WorldWideScience

Sample records for hydrophilic insoluble polymers

  1. Use of Hydrophilic Insoluble Polymers in the Restoration of Metal-Contaminated Soils

    OpenAIRE

    Guiwei Qu; Amarilis de Varennes

    2009-01-01

    To develop cost-effective techniques that contribute to phytostabilization of severely metal-contaminated soils is a necessary task in environmental research. Hydrophilic insoluble polymers have been used for some time in diapers and other hygienic products and to increase the water-holding capacity of coarse-textured soils. These polymers contain groups, such as carboxyl groups, that are capable of forming bonds with metallic cations, thereby decreasing their bioavailability in soils. The us...

  2. Use of Hydrophilic Insoluble Polymers in the Restoration of Metal-Contaminated Soils

    Directory of Open Access Journals (Sweden)

    Guiwei Qu

    2009-01-01

    Full Text Available To develop cost-effective techniques that contribute to phytostabilization of severely metal-contaminated soils is a necessary task in environmental research. Hydrophilic insoluble polymers have been used for some time in diapers and other hygienic products and to increase the water-holding capacity of coarse-textured soils. These polymers contain groups, such as carboxyl groups, that are capable of forming bonds with metallic cations, thereby decreasing their bioavailability in soils. The use of polyacrylate polymers as soil amendments to restore metal-contaminated soils has been investigated in the Technical University of Lisbon since the late nineties. Plant growth and plant nutrients concentrations, extractable levels of metals in soil, and soil enzyme activities were used to monitor the improvement in soil quality following the application of these polymers. In contaminated soils, hydrophilic insoluble polymers can create microcosms that are rich in water and nutrients (counterions but only contain small concentrations of toxic elements; the conditions of these microenvironments are favorable to roots and microorganisms. In this paper we described the most relevant information available about this topic.

  3. Hydrophilic Polymer-associated Ischemic Enterocolitis.

    Science.gov (United States)

    Chavez, Jesus A; Chen, Wei; Frankel, Wendy L; Arnold, Christina A

    2017-02-01

    Hydrophilic polymer coating of medical devices serves to lubricate the device and prevent device-related complications. The coating can be mechanically disrupted and result in downstream injury via presumed thromboembolism. This process has been reported in the brain, heart, lung, and skin, and has been replicated through animal studies and in vitro histologic processing of the polymer coating. We report the first description of hydrophilic polymer-associated ischemic enterocolitis in a series of 7 specimens (small bowel=2, colon=4, aortic thrombus=1) from 3 patients. We report a 4% incidence among all patients with an ischemic bowel resection between April 29, 2014 and August 8, 2016. All patients developed bowel ischemia within 1 day of aortic repair, and all bowel resection specimens showed polymers, mainly in the submucosal vessels in areas of extensive ischemia. The polymers appeared as basophilic, intravascular, serpiginous structures. In a patient who developed acute paralysis after the aortic repair, identical polymers were identified in the aortic thrombus and the ischemic bowel segment. We demonstrate that the polymers display an altered morphology over time and with various graft types, and that the degrading polymers are associated with a foreign body giant cell reaction. Special stains can aid in diagnosis, with the polymers turquoise on a colloidal iron stain, pink on von Kossa and mucicarmine stains, and pale blue on trichrome. Clinical follow-up was available up to 115 weeks: 1 patient died, and 2 are alive and well. In summary, we report a new diagnostic entity to be considered in the differential diagnosis of iatrogenic ischemic injuries in the gastrointestinal tract. Awareness of this entity is important to elucidate the cause of ischemia and to prevent misdiagnosis of the polymers and their associated giant cell reaction as a parasitic infection, granulomatous vasculitis, sarcoidosis, and idiopathic inflammatory bowel disease.

  4. Materials comprising polydienes and hydrophilic polymers and related methods

    Science.gov (United States)

    Mays, Jimmy W [Knoxville, TN; Deng, Suxiang [Knoxville, TN; Mauritz, Kenneth A [Hattiesburg, MS; Hassan, Mohammad K [Hattiesburg, MS; Gido, Samuel P [Hadley, MA

    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. An oral controlled release system for ambroxol hydrochloride containing a wax and a water insoluble polymer.

    Science.gov (United States)

    Chi, Na; Guo, Ju Hong; Zhang, Yu; Zhang, Wei; Tang, Xing

    2010-01-01

    This study was carried out to develop and optimize oral sustained-release formulations for Ambroxol hydrochloride matrix pellets using a combination of wax and water-insoluble polymer, glyceryl behenate (Compritol 888 ATO) and Ethylcellulose (EC(7 FP)). It involved three factors: the content of Compritol 888 ATO (X(1)), EC(7 FP) (X(2)), and the matrix formation methods (X(3)), as independent variables. The drug release percentages at 1, 2 and 4 h were the target responses and were restricted to 15-45% (Y(1)), 45-80% (Y(2)) and 80-100% (Y(3)), respectively. The final blend formulation prepared by extrusion spheronization, was achieved with 27.00% (w/w) Ambroxol hydrochloride, 48.70% (w/w) Compritol 888 ATO, and 24.30% (w/w) EC(7 Fp) with 40 degrees C for 12 h. Comparing the single matrix materials consisting of just the wax or water-insoluble in the complex matrix system containing wax and water-insoluble polymer, the release of the drug can be far more retarded, when the formulations have undergone the process of heat treatment. Furthermore, the combination of the two polymers, with flexible matrix formation methods, will offer a very promising way of producing matrix pellets instead of coated controlled-release pellets to meet various demands of drug release.

  6. Use of hydrophilic polymers from disposable diapers to restore metal contaminated soils

    OpenAIRE

    Varennes, A.

    2010-01-01

    RAMIRAN International Conference Hydrophilic polymers swell to form gels that contain many times their dry weight in water. They are marketed as ‘superabsorbent polymers’, with different trade names, for incorporation into soils and substrates. YunKai et al. (2002) reviewed the effects of these polymers on agricultural soils and crops. Another use of hydrophilic polymers is in disposable diapers and similar products. A layer of polyacrylate polymer is located between cellulose fib...

  7. Role of hydrophilicity and length of diblock arms for determining star polymer physical properties.

    Science.gov (United States)

    Felberg, Lisa E; Brookes, David H; Head-Gordon, Teresa; Rice, Julia E; Swope, William C

    2015-01-22

    We present a molecular simulation study of star polymers consisting of 16 diblock copolymer arms bound to a small adamantane core by varying both arm length and the outer hydrophilic block when attached to the same hydrophobic block of poly-δ-valerolactone. Here we consider two biocompatible star polymers in which the hydrophilic block is composed of polyethylene glycol (PEG) or polymethyloxazoline (POXA) in addition to a polycarbonate-based polymer with a pendant hydrophilic group (PC1). We find that the different hydrophilic blocks of the star polymers show qualitatively different trends in their interactions with aqueous solvent, orientational time correlation functions, and orientational correlation between pairs of monomers of their polymeric arms in solution, in which we find that the PEG polymers are more thermosensitive compared with the POXA and PC1 star polymers over the physiological temperature range we have investigated.

  8. A NOVEL HYDROPHILIC POLYMER MEMBRANE FOR THE DEHYDRATION OF ORGANIC SOLVENTS

    Science.gov (United States)

    Novel hydrophilic polymer membranes based on polyallylamine ydrochloride- polyvinylalcohol are developed. The high selectivity and flux characteristics of these membranes for the dehydration of organic solvents are evaluated using pervaporation technology and are found to be ver...

  9. Study of Hydrophobic and Ionizable Hydrophilic Copolymers at Polymer/Solid and Polymer/Liquid Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Perahia, Dvora

    2011-11-01

    Joint experimental-computational efforts were set to characterize the interfacial effects on the structure and dynamics of polymers consisting of highly rigid hydrophilic-ionizable and hydrophobic sub-units within one polymeric chain casted into thin films of several molecular dimensions. Focusing on the ultra thin film region we separate out the interfacial effects from bulk characteristics. Specifically, the study sought to: identify the parameters that control the formation of a stable polymer-solid interface. The study consists of two components, experimental investigations and computational efforts. The experimental component was designed to derive empirical trends that can be used to correlate the set of coupled polymer molecular parameters with the interfacial characteristics of these polymers, and their response to presence of solvents. The computational study was designed to provide molecular insight into the ensemble averages provided by the experimental efforts on multiple length scales from molecular dimensions, to the nanometer lengths to a macroscopic understanding of solvent interactions with structured polymers. With the ultimate goal of correlating molecular parameters to structure, dynamics and properties of ionic polymers, the first stage of the research began with the study of two systems, one which allowed tailoring the flexibility of the backbone without the presence of ionic groups, but with a potential to sulfonate groups at a later stage, and a polymer whose backbone is rigid and the density of the ionic group can be varied. The combined experimental and computational studies significantly extended the understanding of polymers at interfaces from model systems to polydispersed copolymers with blocks of varying nature and complexity. This new insight directly affects the design of polymers for sustainable energy applications from batteries and fuel cells to solar energy.

  10. Comparison of drug release and mechanical properties of tramadol-hydrochloride matrix tablets prepared with selected hydrophilic polymers

    Directory of Open Access Journals (Sweden)

    Nikolić Nenad D.

    2015-01-01

    Full Text Available This study investigates using of high molecular weight hydrophilic polymers, hypromellose and hydroxypropylcellulose, for the preparation of sustained release matrix tablets containing high dose, highly soluble drug, tramadol HCl. Proportion of polymer, type of insoluble filler, proportion of tramadol HCl, amount of drug in the tablet and compression pressure were recognized as critical formulation and process parameters and their influence on drug release and tablet mechanical properties was evaluated. Tensile strength was used as indicator of mechanical properties of the tablets. Experiments were performed with utilization of compaction simulator as a device which simulates compaction profiles of large scale rotary tablet presses. In formulations with both polymers proportion of tramadol HCl was the most critical formulation parameter wherein increasing of the tramadol HCl proportion increased its release rate in early stages of drug release. Regarding the tablet mechanical characteristics, the influence of the filler type has the most pronounced effect in formulations with both polymers. Higher tensile strengths were obtained with Avicel PH 102 as filler in formulations with both HPMC and HPC. [Projekat Ministarstva nauke Republike Srbije, br. TR 34007

  11. Rheological evaluation of silicon/carbopol hydrophilic gel systems as a vehicle for delivery of water insoluble drugs.

    Science.gov (United States)

    Bonacucina, Giulia; Cespi, Marco; Misici-Falzi, Monica; Palmieri, Giovanni F

    2008-01-01

    The present study analyzed the thickening properties of Carbopol 974 and 971 in a 50:50 mixture of water/Silsense A-21, a new cationic silicon miscible in any proportion with water. Samples were prepared by simply dispersing different Carbopol amounts (0.5-4%) at room temperature or at 70 degrees C without neutralizing. Temperature sweep and time sweep analysis did not reveal significant structural changes at increasing temperature in the samples prepared following the first procedure. On the other hand systems obtained at 70 degrees C possessed higher elastic character particularly at polymer concentration higher than 2% (w/v). Analysis of the G' and G'' vs frequency curves by using different fitting equations (linear fitting, power law) gave information about the viscoelastic properties of the systems. The fitting of the frequency spectra and the calculation of the relaxation times from the master curves outlined the structural differences within the samples prepared with the two different procedures, confirming stronger gel-like behaviour for the samples prepared by the heating procedure. High preparation temperature promoted the polymer-solvent interactions, aiding the solvation of Carbopol. Heating facilitated polymer-solvent and polymer-polymer interaction, giving rise to a better organised structure typical of gel-like systems. Furthermore this preparation method provided good stability properties as shown by the stress sweeps tests performed during the three months of storage. The interpretation of the rheological results was supported by statistical analysis. A design methodology (screening and optimisation) was also applied in order evaluate the influence on dynamic rheological moduli of several parameters (polymer type and concentration, preparation method, temperature of the tests). This last method showed the relevance of the interaction of two main factors: polymer concentration and preparation procedure. Thus, statistical analysis confirmed that

  12. Mitigation of water repellency in burned soils applying hydrophillic polymers

    Science.gov (United States)

    Neris, Jonay; de la Torre, Sara; Vidal-Vazquez, Eva; Lado, Marcos

    2017-04-01

    In this study, the effect of fire on water repellency was analyzed in soils from different parent materials, as well as the suitability of anionic polyacrylamide (PAM) to reduce water repellency in these soils. Samples were collected in four different sites where wildfires took place: two in the Canary Islands, with soils developed on volcanic materials, and two in Galicia (NW Spain), with soils developed on plutonic rocks. In Galicia, two soil samples were collected in each site, one in the burnt area and one in an adjacent unburnt area. In the Canary Islands, four samples were collected from each site, three inside the burnt area where the soils were affected by different fire intensities, and one in an unburnt adjacent area. Samples were air-dried and sieved by a 2-mm mesh sieve. Water repellency was measured using the Water Drop Penetration Time test. An amount of 10 g of soil was placed in a tray. Five drops of deionized water were place on the soil surface with a pipette, and the time for each drop to fully penetrate into the soil was recorded. PAM solution was applied to the burnt soils simulating a field application rate of 1gm-2. The polymer used was Superfloc A-110 (Kemira Water Solutions BV, Holland) with 1x107 Da molecular weigth and 15% hydrolysis. PAM was sprayed on the soil surface as solution with a concentration 0.2 g/L. After the application, the samples were dried and the WDPT test was performed. Three replicates for each treatment and soil were used, and the treatments included: dry soil, dry soil after a wetting treatment, dry PAM-treated soil. The results showed that water repellency was modified by fire differently in the various soils. In hydrophilic soils and soils with low water repellency, water repellency was increased after the action of fire. In soils with noticeable initial water repellency, this was reduced or eliminated after the fire. Wetting repellent soils caused a decrease in water repellency most probably because of the spatial

  13. Release Behaviour of Propranolol HCl from Hydrophilic Matrix Tablets Containing Psyllium Powder in Combination with Hydrophilic Polymers

    OpenAIRE

    Siahi-Shadbad, Mohammad R.; Asare-Addo, Kofi; Azizian, Kakali; Hassanzadeh, Davoud; Nokhodchi, Ali

    2011-01-01

    The objective of this study was to investigate the release behaviour of propranolol hydrochloride from psyllium matrices in the presence hydrophilic polymers. The dissolution test was carried out at pH 1.2 and pH 6.8. Binary mixtures of psyllium and hydroxypropyl methylcellulose (HPMC) used showed that an increase in the percentage of HPMC in the binary mixtures caused a significant decrease in the release rate of propranolol. Psyllium–alginate matrices produced lower drug release as compared...

  14. Ultralow Friction with Hydrophilic Polymer Brushes in Water as Segregated from Silicone Matrix

    DEFF Research Database (Denmark)

    Røn, Troels; Javakhishvili, Irakli; Hvilsted, Søren

    2015-01-01

    - tion coefficients ( μ ) are 0.001–0.05 for soft contacts depending on substrate, load, counter surface, pH, and salinity. Between the two types of hydrophilic polymer chains, PAA shows far superior lubricity compared to PEG, which is rationalized by the larger reduction of total free energy......, as the hydrophilic polymer brushes are generated from an internal source of the material, excellent grafting stability and restoring capabilities are revealed even under harsh tribostress. The film can easily be applied to elastomers, metals, and ceramic substrates by spin- or drip-coating. Obtained sliding fric...

  15. Release behaviour of propranolol HCl from hydrophilic matrix tablets containing psyllium powder in combination with hydrophilic polymers.

    Science.gov (United States)

    Siahi-Shadbad, Mohammad R; Asare-Addo, Kofi; Azizian, Kakali; Hassanzadeh, Davoud; Nokhodchi, Ali

    2011-12-01

    The objective of this study was to investigate the release behaviour of propranolol hydrochloride from psyllium matrices in the presence hydrophilic polymers. The dissolution test was carried out at pH 1.2 and pH 6.8. Binary mixtures of psyllium and hydroxypropyl methylcellulose (HPMC) used showed that an increase in the percentage of HPMC in the binary mixtures caused a significant decrease in the release rate of propranolol. Psyllium-alginate matrices produced lower drug release as compared to when the alginate was the matrix former alone. When sodium carboxy methyl cellulose (NaCMC) was incorporated into the psyllium, the results showed that matrices containing the ratio of psyllium-NaCMC in the 1:1 ratio are able to slow down the drug release significantly as compared to matrices made from only psyllium or NaCMC as retardant agent suggesting that there could be a synergistic effect between psyllium and NaCMC. The double-layered tablets showed that the psyllium and HPMC in the outer shell of an inner formulation of psyllium alone had the greatest effect of protecting the inner core and thus producing the lowest drug release (DE = 38%, MDT = 93 min). A significant decrease in the value of n in Q = kt(n) from 0.70 to 0.51 as the psyllium content was increased from 50 to 150 mg suggests that the presence of psyllium in HPMC matrices affected the release mechanism. Psyllium powder had the ability in the combination with other hydrophilic polymers to produce controlled release profiles. Care and consideration should as such be taken when formulating hydrophilic matrices in different combinations.

  16. Comparison of the performances of four hydrophilic polymers as supports for lipase immobilisation

    OpenAIRE

    Toscano, Lydia; Montero, Gisela; Stoytcheva, Margarita; Cervantes, Lourdes; Gochev, Velizar

    2014-01-01

    Four hydrophilic polymers in the form of beads ? chitosan, alginate, alginate/polyvinyl alcohol (PVA), and chitosan-coated alginate ? were used as supports for lipase immobilisation. Hydrogel beads were characterised by bead-size-distribution estimation, surface morphology studies, and polymer interactions assessment. Matrix performances ? loading efficiency, immobilisation yield, enzyme activity, and stability retention ? were evaluated and compared. Although the loading efficiency of the ch...

  17. Photochemical coating of Kapton® with hydrophilic polymers for the improvement of neural implants.

    Science.gov (United States)

    Hadler, Christoph; Wissel, Kirsten; Brandes, Gudrun; Dempwolf, Wibke; Reuter, Günter; Lenarz, Thomas; Menzel, Henning

    2017-06-01

    The polyimide Kapton® was coated photochemically with hydrophilic polymers to prevent undesirable cell growth on the polyimide surface. The polymer coatings were generated using photochemically reactive polymers synthesized by a simple and modular strategy. Suitable polymers or previously synthesized copolymer precursors were functionalized with photoactive arylazide groups by a polymer analogous amide coupling reaction with 4-azidobenzoic acid. A photoactive chitosan derivative (chitosan-Az) and photochemically reactive copolymers containing DMAA, DEAA or MTA as primary monomers were synthesized using this method. The amount of arylazide groups in the polymers was adjusted to approximately 5%, 10% and 20%. As coating on Kapton® all polymers effect a significantly reduced water contact angle (WCA) and consequently a rise of the surface hydrophilicity compared to the untreated Kapton®. The presence of the polymer coatings was also proven by ATR-IR spectroscopy. Coatings with chitosan-Az and the DEAA copolymer cause a distinct inhibition of the growth of fibroblasts. In the case of the DMAA copolymer even a strong anti-adhesive behavior towards fibroblasts was verified. Biocompatibility of the polymer coatings was proven which enables their utilization in biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Influence of hydrophilic polymers on functional properties and wound healing efficacy of hydrocolloid based wound dressings.

    Science.gov (United States)

    Jin, Sung Giu; Yousaf, Abid Mehmood; Kim, Kyeong Soo; Kim, Dong Wuk; Kim, Dong Shik; Kim, Jin Ki; Yong, Chul Soon; Youn, Yu Seok; Kim, Jong Oh; Choi, Han-Gon

    2016-03-30

    The purpose of this study was to investigate the influence of different hydrophilic polymers on the swelling, bioadhesion and mechanical strength of hydrocolloid wound dressings (HCDs) in order to provide an appropriate composition for a hydrocolloid wound dressing system. In this study, the HCDs were prepared with styrene-isoprene-styrene copolymer (SIS) and polyisobutylene (PIB) as the base using a hot melting method. Additionally, numerous SIS/PIB-based HCDs were prepared with six hydrophilic polymers, and their wound dressing properties were assessed. Finally, the wound healing efficacy of the selected formulations was compared to a commercial wound dressing. The swelling ratio, bioadhesive force and mechanical strengths of HCDs were increased in the order of sodium alginate>sodium CMC=poloxamer=HPMC>PVA=PVP, sodium alginate>sodium CMC=poloxamer>PVA>HPMC=PVP and sodium alginate≥PVA>PVP=HPMC=sodium CMC>poloxamer, respectively. Among the hydrophilic polymers tested, sodium alginate most enhanced the swelling capacity, bioadhesive force and mechanical strengths. Thus, the hydrophilic polymers played great role in the swelling, bioadhesion and mechanical strength of SIS/PIB-based HCDs. The HCD formulation composed of PIB, SIS, liquid paraffin and sodium alginate at the weight ratio of 20/25/12/43 gave better wound dressing properties and more excellent wound healing efficacy than the commercial wound dressing. Therefore, the novel HCD formulation could be a promising hydrocolloid system for wound dressings. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Influence of Different Polymer Types on the Overall Release Mechanism in Hydrophilic Matrix Tablets

    Directory of Open Access Journals (Sweden)

    Bengt Wittgren

    2009-07-01

    Full Text Available The effect of three different types of polymer chain structures on the polymer release from hydrophilic matrix tablets was investigated by comparing a synthetic semi-crystalline linear polymer (PEO, a branched amorphous polysaccharide (dextran and an amorphous substituted cellulose derivative (HPMC. The polymer release rates for tablets containing mixtures of high and low molecular weight grades in different ratios were determined by using a modified USP II method and a SEC-RI chromatography system. The results showed that independent of polymer type: (i plots of the release versus time had similar shapes, (ii the release of long and short polymer chains was equal and no fractionation occurred during the release and (iii the release rate could be related to the average intrinsic viscosity of the polymer mixtures. This confirms the hypothesis that the release rate can be related to a constant viscosity on the surface of the hydrophilic matrix tablet and that it is valid for all the investigated polymers.

  20. The effect of polymer properties on direct compression and drug release from water-insoluble controlled release matrix tablets.

    Science.gov (United States)

    Grund, Julia; Koerber, Martin; Walther, Mathias; Bodmeier, Roland

    2014-07-20

    The objective of this study was to identify and evaluate key polymer properties affecting direct compression and drug release from water-insoluble matrices. Commonly used polymers, such as Kollidon(®) SR, Eudragit(®) RS and ethyl cellulose, were characterized, formulated into tablets and compared with regard to their properties in dry and wet state. A similar site percolation threshold of 65% v/v was found for all polymers in dry state. Key parameters influencing polymer compactibility were the surface properties and the glass transition temperature (T(g)), affecting polymer elasticity and particle size-dependent binding. The important properties observed in dry state also governed matrix characteristics and therefore drug release in wet state. A low T(g) (Kollidon(®) SRpolymer (ethyl cellulose). However, release retardation was observed in the same order as matrix integrity (Eudragit(®) RSpolymer need to be considered in polymer design and formulation of controlled-release matrix systems. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Hydrophilic polymer-coated microcatheter-guide wire system for superselective angiographic procedures

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Hisashi; Hiraki, Yoshiyuki; Nishimoto, Hidetou; Miyazono, Nobuaki; Satake, Mitsuo; Shinohara, Shinji

    1988-06-01

    A hydrophilic polymer-coated microcatheter-guide wire device has been newly developed for superselective angiography and interventional procedures. The injection rate of this microcatheter was estimated at 2.0 ml/sec. on the maximum pressure of 300 psi when used a non-ionic low osmolar contrast medium, Iopamidol 300. In two of three cases this catheter could make easy insertion into the peripheral branches of the right hepatic artery which were approximately 1 mm in vascular diameter.

  2. A prospective randomized study of hydrophilic polymer-coated polyurethane versus polyethylene stents in distal malignant biliary obstruction

    NARCIS (Netherlands)

    van Berkel, A. M.; Bruno, M. J.; Bergman, J. J. G. H. M.; van Deventer, S. J.; Tytgat, G. N. J.; Huibregtse, K.

    2003-01-01

    Background and Study Aims: Hydrophilic polymer-coated polyurethane (HPCP) stents have a low friction coefficient and a hydrophilic layer, which may reduce biofilm formation and increase the period of stent patency. We compared the patency rates with this new stent with the standard Amsterdam-type

  3. Phase behavior, rheological and mechanical properties of hydrophilic polymer dispersions.

    Science.gov (United States)

    Bhattarai, Sushila; Bunt, Craig; Rathbone, Michael; Alany, Raid G

    2011-06-01

    Liquid polymeric systems that can undergo phase change (sol to gel) upon administration into the teat canal of cow's mammary gland can serve as a physical barrier to invading pathogens and can also serve as a reservoir for controlled release of therapeutic agents. The aim of the study was to investigate the phase behavior, rheological and mechanical properties of selected in situ gelling systems. Six in situ gelling polymer formulations were identified using phase behavior studies. Rheological studies revealed pseudoplastic flow with thixotropy. All six formulations showed significantly different viscosity, pseudoplasticity and thixotropy values except for CMC1 and HPMC2 which where statistically similar. The gel strength was dependent on the solvent system used and amount of water in the system. These in situ gelling systems have the potential to serve as a platform for development of intramammary formulations intended for administration into the teat canal of the cow's mammary gland. They can serve as a physical barrier or a matrix for controlled drug release.

  4. Fast formation of hydrophilic and reactive polymer micropatterns by photocatalytic lithography method

    Science.gov (United States)

    Chang, Chi-Jung; Wang, Chih-Feng; Chen, Jem-Kun; Hsieh, Chih-Chiao; Chen, Po-An

    2013-12-01

    An approach is developed for the fast formation of a hydrophilic pattern on superhydrophobic substrates with good contrast due to the large wettability contrast between superhydrophobic and superhydrophilic areas. It can be used for forming a polymer pattern with reactive functional groups. TiO2 nanoparticles were grafted with long alkyl chains and then coated on substrates to produce superhydrophobic films. Photocatalytic degradation of the grafted alkyl chains was effected with UV light irradiation and resulted in transition from superhydrophobicity to superhydrophilicity. After UV light irradiation through a mask for 30 s, dyes or polymers were adsorbed on the photoinduced superhydrophilic areas to make micropatterns. The photoinduced superhydrophilic switching properties can be tuned by changing the alkyl chain length. The ninhydrin assay was adapted to identify free amino groups of polymers on the patterned area. Polymer patterns with free amino groups can be achieved.

  5. Fast formation of hydrophilic and reactive polymer micropatterns by photocatalytic lithography method

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chi-Jung, E-mail: changcj@fcu.edu.tw [Department of Chemical Engineering, Feng Chia University, 100, Wenhwa Road, Seatwen, Taichung 407, Taiwan (China); Wang, Chih-Feng [Department of Materials Science and Engineering, I-Shou University, 1, Syuecheng Road, Dashu District, Kaohsiung 840, Taiwan (China); Chen, Jem-Kun [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Road, Taipei 106, Taiwan (China); Hsieh, Chih-Chiao; Chen, Po-An [Department of Chemical Engineering, Feng Chia University, 100, Wenhwa Road, Seatwen, Taichung 407, Taiwan (China)

    2013-12-01

    An approach is developed for the fast formation of a hydrophilic pattern on superhydrophobic substrates with good contrast due to the large wettability contrast between superhydrophobic and superhydrophilic areas. It can be used for forming a polymer pattern with reactive functional groups. TiO{sub 2} nanoparticles were grafted with long alkyl chains and then coated on substrates to produce superhydrophobic films. Photocatalytic degradation of the grafted alkyl chains was effected with UV light irradiation and resulted in transition from superhydrophobicity to superhydrophilicity. After UV light irradiation through a mask for 30 s, dyes or polymers were adsorbed on the photoinduced superhydrophilic areas to make micropatterns. The photoinduced superhydrophilic switching properties can be tuned by changing the alkyl chain length. The ninhydrin assay was adapted to identify free amino groups of polymers on the patterned area. Polymer patterns with free amino groups can be achieved.

  6. Fast and Simple Preparation of Patterned Surfaces with Hydrophilic Polymer Brushes by Micromolding in Capillaries.

    Science.gov (United States)

    Vonhören, Benjamin; Langer, Marcel; Abt, Doris; Barner-Kowollik, Christopher; Ravoo, Bart Jan

    2015-12-22

    Micropatterns of hydrophilic polymer brushes were prepared by micromolding in capillaries (MIMIC). The polymers are covalently bound to the surfaces by a rapid hetero Diels-Alder reaction, constituting the first example of polymers grafted to surfaces in a defined pattern by MIMIC. The polymers [poly(acrylic acid), poly(hydroxyethyl acrylate), and poly(tetraethylene glycol acrylate) ranging in molecular weight from 1500 to 6000 g mol(-1)] were prepared with narrow dispersities via the reversible addition-fragmentation chain transfer (RAFT) process using a highly electron deficient RAFT agent that can react with surface-anchored dienes such as cyclopentadiene. We demonstrate that the anchoring method is facile to perform and highly suitable for preparing patterned surfaces that are passivated against biological impact in well-defined areas.

  7. Formulation of gastroretentive floating drug delivery system using hydrophilic polymers and its in vitro characterization

    Directory of Open Access Journals (Sweden)

    Venkata Srikanth Meka

    2014-04-01

    Full Text Available The aim of the present research is to formulate and evaluate the gastroretentive floating drug delivery system of antihypertensive drug, propranolol HCl. Gastroretentive floating tablets (GRFT were prepared by using a synthetic hydrophilic polymer polyethylene oxide of different grades such as PEO WSR N-12 K and PEO 18 NF as release retarding polymers and calcium carbonate as gas generating agent. The GRFT were compressed by direct compression strategy and the tablets were evaluated for physico-chemical properties, in vitro buoyancy, swelling studies, in vitro dissolution studies and release mechanism studies. From the dissolution and buoyancy studies, F 9 was selected as an optimized formulation. The optimized formulation followed zero order rate kinetics with non-Fickian diffusion mechanism. The optimized formulation was characterised with FTIR studies and observed no interaction between the drug and the polymers.

  8. Embedding of Hollow Polymer Microspheres with Hydrophilic Shell in Nafion Matrix as Proton and Water Micro-Reservoir

    Directory of Open Access Journals (Sweden)

    Zhaolin Liu

    2012-08-01

    Full Text Available Assimilating hydrophilic hollow polymer spheres (HPS into Nafion matrix by a loading of 0.5 wt % led to a restructured hydrophilic channel, composed of the pendant sulfonic acid groups (–SO3H and the imbedded hydrophilic hollow spheres. The tiny hydrophilic hollow chamber was critical to retaining moisture and facilitating proton transfer in the composite membranes. To obtain such a tiny cavity structure, the synthesis included selective generation of a hydrophilic polymer shell on silica microsphere template and the subsequent removal of the template by etching. The hydrophilic HPS (100–200 nm possessed two different spherical shells, the styrenic network with pendant sulfonic acid groups and with methacrylic acid groups, respectively. By behaving as microreservoirs of water, the hydrophilic HPS promoted the Grotthus mechanism and, hence, enhanced proton transport efficiency through the inter-sphere path. In addition, the HPS with the –SO3H borne shell played a more effective role than those with the –CO2H borne shell in augmenting proton transport, in particular under low humidity or at medium temperatures. Single H2-PEMFC test at 70 °C using dry H2/O2 further verified the impactful role of hydrophilic HPS in sustaining higher proton flux as compared to pristine Nafion membrane.

  9. Determination of gelation doses of gamma-irradiated hydrophilic polymers by different methods

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Fatma; Tekin, Niket; Erkan, Sevin; Gueven, Olgun (Hacettepe Univ., Ankara (Turkey). Dept. of Chemistry)

    1994-04-01

    Poly(acrylic acid) and poly(vinyl pyrrolidone) are hydrophilic polymers. Poly(acrylic acid) is a polyelectrolyte which ionizes in water to produce an electrically conducting medium. In this study, it has been shown that the gelation dose of poly(acrylic acid) can be determined by conductimetric and titrimetric methods with NaOH and measuring pH of aqueous solution of [gamma]-irradiated polymer. In order to develop new, simpler and rapid methods for the determination of gelation dose of PVP, its complexation with gallic acid in dilute aqueous solution has been used. The complex formation between gallic acid and irradiated PVP in aqueous solutions is followed by UV-vis spectroscopy. The reliability of the dose value found, 120 kGy for poly(acrylic acid) and 140 kGy for poly(vinyl pyrrolidone), are also verified by viscometric and solubility measurements. (author).

  10. Polypeptoids from N -Substituted Glycine N -Carboxyanhydrides: Hydrophilic, Hydrophobic, and Amphiphilic Polymers with Poisson Distribution

    KAUST Repository

    Fetsch, Corinna

    2011-09-13

    Preparation of defined and functional polymers has been one of the hottest topics in polymer science and drug delivery in the recent decade. Also, research on (bio)degradable polymers gains more and more interest, in particular at the interface of these two disciplines. However, in the majority of cases, combination of definition, functionality and degradability, is problematic. Here we present the preparation and characterization (MALDI-ToF MS, NMR, GPC) of nonionic hydrophilic, hydrophobic, and amphiphilic N-substituted polyglycines (polypeptoids), which are expected to be main-chain degradable and are able to disperse a hydrophobic model compound in aqueous media. Polymerization kinetics suggest that the polymerization is well controlled with strictly linear pseudo first-order kinetic plots to high monomer consumption. Moreover, molar mass distributions of products are Poisson-type and molar mass can be controlled by the monomer to initiator ratio. The presented polymer platform is nonionic, backbone degradable, and synthetically highly flexible and may therefore be valuable for a broad range of applications, in particular as a biomaterial. © 2011 American Chemical Society.

  11. Thermochemical Properties of Hydrophilic Polymers from Cashew and Khaya Exudates and Their Implications on Drug Delivery

    Directory of Open Access Journals (Sweden)

    Emmanuel O. Olorunsola

    2016-01-01

    Full Text Available Characterization of a polymer is essential for determining its suitability for a particular purpose. Thermochemical properties of cashew gum (CSG extracted from exudates of Anacardium occidentale L. and khaya gum (KYG extracted from exudates of Khaya senegalensis were determined and compared with those of acacia gum BP (ACG. The polymers were subjected to different thermal and chemical analyses. Exudates of CSG contained higher amount of hydrophilic polymer. The pH of 2% w/v gum dispersions was in the order KYG < CSG < ACG. Calcium was the predominant ion in CSG while potassium was predominant in KYG. The FTIR spectra of CSG and KYG were similar and slightly different from that of ACG. Acacia and khaya gums exhibited the same thermal behaviour which is different from that of CSG. X-ray diffraction revealed that the three gums are the same type of polymer, the major difference being the concentration of metal ions. This work suggests the application of cashew gum for formulation of basic and oxidizable drugs while using khaya gum for acidic drugs.

  12. Hydrophilic surface modification of polymer vascular prostheses and metal endoluminal stents

    Science.gov (United States)

    Amery, Drew Powell

    1997-12-01

    Large diameter vascular replacements of GORE-TEXsp°ler or Dacronsp°ler are frequently used to replace damaged arteries. Poor long term patency of small diameter grafts, 6 millimeters or less, is attributed to platelet adhesion and the inability to regenerate a blood contacting surface of vascular endothelium. Metal endoluminal stents are vascular prostheses used to keep arterial lumens open following angioplasty. Complications for these implants include short term thrombogenicity and long term restenosis. This study was directed to the synthesis and characterization of more biocompatible surfaces for these devices. Gamma radiation induced-graft polymerization and radio frequency plasma activation was investigated to surface modify polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), expanded polytetrafluoroethylene (ePTFE), and 316 stainless steel. To mimic natural biocompatible tissue surfacesl a series of hydrophilic polymers were grafted onto PMMA, PET, and ePTFE. Hydrophilic graft polymers were derived from N-vinyl pyrrolidone (NVP), potassium sulfopropylacrylate (KSPA), and dimethylacrylamide, and were grafted copolymerized with several bioactive compounds in a two step modification process. Complex graft surfaces containing fibronectin (Fn), laminin (Lm), type IV collagen (IV), heparin sulfate (Hp), albumin (Alb), and a synthetic fibronectin like protein polymer (RGD) were prepared. For surface modification of endoluminal stents of 316 stainless and tantalum, a combination of RF plasma activation combined with gamma radiation induced grafting was studied. Plasma deposition of hydrophobic poly(hexane) primer layers with water plasma oxidation were examined for initial metal surface activation. Surfaces were characterized by gravimetric analysis, contact angle goniometry, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Auger depth proGling, optical microscopy (OM), and low voltage scanning electron

  13. Inhibition of pulmonary surfactant adsorption by serum and the mechanisms of reversal by hydrophilic polymers: theory

    DEFF Research Database (Denmark)

    Zasadzinski, Joseph A; Alig, T F; Alonso, Coralie

    2005-01-01

    A theory based on the Smolukowski analysis of colloid stability shows that the presence of charged, surface-active serum proteins at the alveolar air-liquid interface can severely reduce or eliminate the adsorption of lung surfactant from the subphase to the interface, consistent with the observa......A theory based on the Smolukowski analysis of colloid stability shows that the presence of charged, surface-active serum proteins at the alveolar air-liquid interface can severely reduce or eliminate the adsorption of lung surfactant from the subphase to the interface, consistent...... with the observations reported in the companion article (pages 1769-1779). Adding nonadsorbing, hydrophilic polymers to the subphase provides a depletion attraction between the surfactant aggregates and the interface, which can overcome the steric and electrostatic resistance to adsorption induced by serum...... in the alveolar fluids, can enhance adsorption in the presence of serum to eliminate inactivation. Udgivelsesdato: 2005-Sep...

  14. Protein Stability during Hot Melt Extrusion: The Effect of Extrusion Temperature, Hydrophilicity of Polymers and Sugar Glass Pre-stabilization

    OpenAIRE

    Teekamp, Naomi; Olinga, Peter; Frijlink, Henderik W.; Hinrichs, Wouter

    2015-01-01

    Purpose Biodegradable polymers have been widely investigated for controlled release formulations for protein delivery. However, the processing stability of proteins remains a major challenge. The aim of this research is to assess the influence of the hot melt extrusion process on the activity of a model protein by varying extrusion temperature, hydrophilicity of polymer and pre-stabilization of proteins with sugar glass technology. Methods The thermolabile model protein alkaline phosphatase (...

  15. Surface morphological modification of crosslinked hydrophilic co-polymers by nanosecond pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Primo, Gastón A.; Alvarez Igarzabal, Cecilia I. [IMBIV (CONICET), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba X5000HUA (Argentina); Pino, Gustavo A.; Ferrero, Juan C. [INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, and Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Córdoba X5000IUS (Argentina); Rossa, Maximiliano, E-mail: mrossa@fcq.unc.edu.ar [INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, and Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Córdoba X5000IUS (Argentina)

    2016-04-30

    Graphical abstract: - Highlights: • Laser-induced surface modification of crosslinked hydrophilic co-polymers by ns pulses. • Formation of ablation craters observed under most of the single-pulse experimental conditions. • UV laser foaming of dried hydrogel samples resulting from single- and multiple-pulse experiments. • Threshold values of the incident laser fluence reported for the observed surface modifications. • Lower threshold fluences for acrylate-based, compared to acrylamide-based hydrogels. - Abstract: This work reports an investigation of the surface modifications induced by irradiation with nanosecond laser pulses of ultraviolet and visible wavelengths on crosslinked hydrophilic co-polymeric materials, which have been functionalized with 1-vinylimidazole as a co-monomer. A comparison is made between hydrogels differing in the base co-monomer (N,N-dimethylaminoethyl methacrylate and N-[3-(dimethylamino)propyl] methacrylamide) and in hydration state (both swollen and dried states). Formation of craters is the dominant morphological change observed by ablation in the visible at 532 nm, whereas additional, less aggressive surface modifications, chiefly microfoams and roughness, are developed in the ultraviolet at 266 nm. At both irradiation wavelengths, threshold values of the incident laser fluence for the observation of the various surface modifications are determined under single-pulse laser irradiation conditions. It is shown that multiple-pulse irradiation at 266 nm with a limited number of laser shots can be used alternatively for generating a regular microfoam layer at the surface of dried hydrogels based on N,N-dimethylaminoethyl methacrylate. The observations are rationalized on the basis of currently accepted mechanisms for laser-induced polymer surface modification, with a significant contribution of the laser foaming mechanism. Prospective applications of the laser-foamed hydrogel matrices in biomolecule immobilization are suggested.

  16. Volume effect of non-polar solvent towards the synthesis of hydrophilic polymer nanoparticles prepares via inverse miniemulsion polymerization

    Science.gov (United States)

    Kamaruddin, Nur Nasyita; Kassim, Syara; Harun, Noor Aniza

    2017-09-01

    Polymeric nanoparticles have drawn tremendous attention to researchers and have utilized in diverse fields especially in biomedical applications. Nevertheless, question has raised about the safety and hydrophilicity of the nanoparticles to be utilized in medical and biological applications. One promising solution to this problem is to develop biodegradable polymeric nanoparticles with improve hydrophilicity. This study is focusing to develop safer and "greener" polymeric nanoparticles via inverse miniemulsion polymerization techniques, a robust and convenient method to produce water-soluble polymer nanoparticles. Acrylamide (Am), acrylic acid (AA) and methacrylic acid (MAA) monomers have chosen, as they are biocompatible, non-toxic and ecological. The effect of different volumes of cyclohexane towards the formation of polymer nanoparticles, particle size, particle size distribution and morphology of polymer nanoparticles are investigated. The formation and morphology of polymer nanoparticles are determined using FTIR and SEM respectively. The mean diameters of the polymer nanoparticles were in a range of 80 - 250 nm and with broad particle size distributions as determined by dynamic light scattering (DLS). Hydrophilic polyacrylamide (pAm), poly(acrylic acid) (pAA) and poly(methacrylic acid) (pMAA) nanoparticles were successfully achieved by inverse miniemulsion polymerization and have potentiality to be further utilized in the fabrication of hybrid polymer composite nanoparticles especially in biological and medical applications.

  17. On the stability of the polymer brushes formed by adsorption of ionomer complexes on hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Brzozowska, A.M.; Spruijt, E.; Keizer, de A.; Cohen Stuart, M.A.; Norde, W.

    2011-01-01

    We have studied the effect of normal forces and shear forces on the stability and functionality of a polymer brush layer formed upon adsorption of polymeric micelles on hydrophilic and hydrophobic surfaces. The micelles consist of oppositely charged polyelectrolyte blocks (poly(acrylic acid) and

  18. On the stability of the polymer brushes formed by adsorption of Ionomer Complexes on hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Brzozowska, A. M.; Spruijt, E.; de Keizer, A.; Stuart, M. A. Cohen; Norde, W.

    2011-01-01

    We have studied the effect of normal forces and shear forces on the stability and functionality of a polymer brush layer formed upon adsorption of polymeric micelles on hydrophilic and hydrophobic surfaces. The micelles consist of oppositely charged polyelectrolyte blocks (poly(acrylic acid) and

  19. Root desiccation and drought stress responses of bareroot Quercus rubra seedlings treated with a hydrophilic polymer root dip

    Science.gov (United States)

    Kent G. Apostol; Douglass F. Jacobs; R. Kasten Dumroese

    2009-01-01

    Root hydrogel, a hydrophilic polymer, has been used to improve transplanting success of bareroot conifer seedlings through effects on water holding capacity. We examined mechanisms by which Terra-sorb Fine Hydrogel reduces damage that occurs when roots of 1-year old, dormant northern red oak (Quercus rubra L.) were subjected to shortterm (1, 3, and 5...

  20. Application of water-insoluble polymers to orally disintegrating tablets treated by high-pressure carbon dioxide gas.

    Science.gov (United States)

    Ito, Yoshitaka; Maeda, Atsushi; Kondo, Hiromu; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2016-09-10

    The phase transition of pharmaceutical excipients that can be induced by humidifying or heating is well-known to increase the hardness of orally disintegrating tablets (ODTs). However, these conditions are not applicable to drug substances that are chemically unstable against such stressors. Here, we describe a system which enhances the hardness of tablets containing water-insoluble polymers by using high-pressure carbon dioxide (CO2). On screening of 26 polymeric excipients, aminoalkyl methacrylate copolymer E (AMCE) markedly increased tablet hardness (+155N) when maintained in a high-pressure CO2 environment. ODTs containing 10% AMCE were prepared and treatment with 4.0MPa CO2 gas at 25°C for 10min increased the hardness to +30N, whose level corresponded to heating at 70°C for 720min. In addition, we confirmed the effects of CO2 pressure, temperature, treatment time, and AMCE content on the physical properties of ODTs. Optimal pressure of CO2 gas was considered to be approximately 3.5MPa for an AMCE formula, as excessive pressure delayed the disintegration of ODTs. Combination of high-pressure CO2 gas and AMCE is a prospective approach for increasing the tablet hardness for ODTs, and can be conducted without additional heat or moisture stress using a simple apparatus. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Effect of surfactant species and electrophoretic medium composition on the electrophoretic behavior of neutral and water-insoluble linear synthetic polymers in nonaqueous capillary zone electrophoresis.

    Science.gov (United States)

    Fukai, Nao; Kitagawa, Shinya; Ohtani, Hajime

    2017-07-01

    We have recently demonstrated the separation of neutral and water-insoluble linear synthetic polymers in nonaqueous capillary zone electrophoresis (NACZE) using a cationic surfactant of cetyltrimethylammonium chloride (CTAC). In this study, eight ionic surfactants were investigated for the separation of four synthetic polymers (polystyrene, polymethylmethacrylates, polybutadiene, and polycarbonate); only three surfactants (CTAC, dimethyldioctadecylammonium bromide, and sodium dodecylsulfate) caused their separation. The order of the interaction between the polymers and the surfactants depended on both the surfactant species and the composition of the electrophoretic medium. Their investigation revealed that the separation is majorly affected by the hydrophobic interactions between the polymers and the ionic surfactants. In addition, the electrophoretic behavior of polycarbonate suggested that electrostatic interaction also affects the selectivity of the polymers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Hydrophilic Conjugated Polymers with Large Bandgaps and Deep-Lying HOMO Levels as an Efficient Cathode Interlayer in Inverted Polymer Solar Cells.

    Science.gov (United States)

    Kan, Yuanyuan; Zhu, Yongxiang; Liu, Zhulin; Zhang, Lianjie; Chen, Junwu; Cao, Yong

    2015-08-01

    Two hydrophilic conjugated polymers, PmP-NOH and PmP36F-NOH, with polar diethanol-amine on the side chains and main chain structures of poly(meta-phenylene) and poly(meta-phenylene-alt-3,6-fluorene), respectively, are successfully synthesized. The films of PmP-NOH and PmP36F-NOH show absorption edges at 340 and 343 nm, respectively. The calculated optical bandgaps of the two polymers are 3.65 and 3.62 eV, respectively, the largest ones so far reported for hydrophilic conjugated polymers. PmP-NOH and PmP36F-NOH also possess deep-lying highest occupied molecular orbital levels of -6.19 and -6.15 eV, respectively. Inserting PmP-NOH and PmP36F-NOH as a cathode interlayer in inverted polymer solar cells with a PTB7/PC71 BM blend as the active layer, high power conversion efficiencies of 8.58% and 8.33%, respectively, are achieved, demonstrating that the two hydrophilic polymers are excellent interlayers for efficient inverted polymer solar cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Kinetic Modelling of Drug Release from Pentoxifylline Matrix Tablets based on Hydrophilic, Lipophilic and Inert Polymers

    Directory of Open Access Journals (Sweden)

    Mircia Eleonora

    2015-12-01

    Full Text Available Pentoxifylline is a xanthine derivative used in the treatment of peripheral vascular disease, which because of its pharmacokinetic and pharmacologic profile is an ideal candidate for the development of extended release formulations. The aim of this study is to present a kinetic analysis of the pentoxifylline release from different extended release tablets formulations, using mechanistic and empirical kinetic models. A number of 28 formulations were prepared and analysed; the analysed formulations differed in the nature of the matrix forming polymers (hydrophilic, lipophilic, inert and in their concentrations. Measurements were conducted in comparison with the reference product Trental 400 mg (Aventis Pharma. The conditions for the dissolution study were according to official regulations of USP 36: apparatus no. 2, dissolution medium water, volume of dissolution medium is 1,000 mL, rotation speed is 50 rpm, spectrophotometric assay at 274 nm. Six mathematical models, five mechanistic (0 orders, 1st-order release, Higuchi, Hopfenberg, Hixson-Crowell and one empirical (Peppas, were fitted to pentoxifylline dissolution profile from each pharmaceutical formulation. The representative model describing the kinetics of pentoxifylline release was the 1st-order release, and its characteristic parameters were calculated and analysed.

  4. Collaboration between HPMC and NaCMC in order to Reach the Polymer Critical Point in Theophylline Hydrophilic Matrices

    Directory of Open Access Journals (Sweden)

    L. Contreras

    2012-01-01

    Full Text Available Percolation theory has been applied in order to study the existence of critical points as well as the possibility to find a “combined percolation threshold” for ternary hydrophilic matrices prepared with HPMC, NaCMC, and theophylline. For this purpose, different batches of ternary as well as binary hydrophilic matrices have been prepared. Critical points have been found for binary hydrophilic matrices between 21.5 and 31.3% (v/v of HPMC and between 39 and 54% (v/v of NaCMC, respectively. In a previous work carried out with the same polymers but a much more soluble drug (KCl, it was demonstrated the existence of a partial collaboration between the polymers in order to establish the gel layer. In this work, it has been observed for the first time the need of a minimum concentration of one of the matrix-forming polymer (between 10 and 20% v/v, approximately for establishing an effective collaboration.

  5. Collaboration between HPMC and NaCMC in order to Reach the Polymer Critical Point in Theophylline Hydrophilic Matrices

    Science.gov (United States)

    Contreras, L.; Melgoza, L. M.; Aguilar-de-Leyva, A.; Caraballo, I.

    2012-01-01

    Percolation theory has been applied in order to study the existence of critical points as well as the possibility to find a “combined percolation threshold” for ternary hydrophilic matrices prepared with HPMC, NaCMC, and theophylline. For this purpose, different batches of ternary as well as binary hydrophilic matrices have been prepared. Critical points have been found for binary hydrophilic matrices between 21.5 and 31.3% (v/v) of HPMC and between 39 and 54% (v/v) of NaCMC, respectively. In a previous work carried out with the same polymers but a much more soluble drug (KCl), it was demonstrated the existence of a partial collaboration between the polymers in order to establish the gel layer. In this work, it has been observed for the first time the need of a minimum concentration of one of the matrix-forming polymer (between 10 and 20% v/v, approximately) for establishing an effective collaboration. PMID:22919292

  6. Aptamer functionalized hydrophilic polymer monolith with gold nanoparticles modification for the sensitive detection of human α-thrombin.

    Science.gov (United States)

    Chen, Yuanbo; Deng, Nan; Wu, Ci; Liang, Yu; Jiang, Bo; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-07-01

    Low abundant proteins of body fluids participate nearly all physiological processes and indicate various kinds of diseases. The development of specific enrichment techniques is the key to identify and quantify the low abundant proteins. Herein, a novel kind of aptamer functionalized hydrophilic polymer monolith was developed for the specific enrichment and detection of human α-thrombin from the human plasma. Human α-thrombin aptamer, with thiol group modified at the 5' terminal, was immobilized on the gold nanoparticles (AuNPs) modified poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate) monolithic column, with the binding capacity of 277.1μmol/L. Due to the hydrophilic poly(ethylene glycol) diacrylate) as the cross-linking monomer, the detection recovery of the aptamer-functionalized hydrophilic polymer monolithic column could reach to 92.6±5.2% (n=3) and the dynamic range could reach 0.5-300ng/μL (S/N>10) with on-line UV detection. Meanwhile, the column could run over 100 times, because the poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate) stability structure and the AuNPs improved the stability of the matrix material. Furthermore, this column could even capture the target α-thrombin, which was spiked in 1000 folds of original human plasma. All these results demonstrated the great potential of the prepared aptamer functionalized hydrophilic polymer monolith for the recognition of the trace proteins in the biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Improved human bioavailability of vemurafenib, a practically insoluble drug, using an amorphous polymer-stabilized solid dispersion prepared by a solvent-controlled coprecipitation process.

    Science.gov (United States)

    Shah, Navnit; Iyer, Raman M; Mair, Hans-Juergen; Choi, Duk Soon; Tian, Hung; Diodone, Ralph; Fähnrich, Karsten; Pabst-Ravot, Anni; Tang, Kin; Scheubel, Emmanuel; Grippo, Joseph F; Moreira, Sebastian A; Go, Zenaida; Mouskountakis, James; Louie, Theresa; Ibrahim, Prabha N; Sandhu, Harpreet; Rubia, Linda; Chokshi, Hitesh; Singhal, Dharmendra; Malick, Waseem

    2013-03-01

    The present work deals with improving the solubility of vemurafenib, a practically insoluble drug, by converting it into an amorphous-solid dispersion using a solvent-controlled precipitation process. The dispersion containing vemurafenib and hypromellose acetate succinate (HPMCAS), an enteric polymer, is termed microprecipitated bulk powder (MBP), in which the drug is uniformly dispersed within the polymeric substrate. HPMCAS was found to be the most suitable polymer for vemurafenib MBP, among a series of enteric polymers based on superior physical stability and drug-release characteristics of the MBP. The MBP provided a greater rate and extent of dissolution than crystalline drug, reaching an apparent drug concentration of 28-35 µg/mL, almost 30-fold higher than solubility of crystalline drug at 1 µg/mL. The supersaturation was also maintained for more than 4 h. Upon exposure to high temperature and humidity, the MBP was destabilized, resulting in crystallization and lower dissolution rate. The control of moisture and temperature is essential to maintain the stability of the MBP. In a relative human bioavailability study, vemurafenib MBP provided a four- to fivefold increase in exposure compared with crystalline drug. Improving solubility with an amorphous-solid dispersion is a viable strategy for the development of practically insoluble compounds. Copyright © 2012 Wiley Periodicals, Inc.

  8. Use of hydrophilic polymers from diapers to aid the establishment of Spergularia purpurea in a mine soil.

    Science.gov (United States)

    Qu, G; de Varennes, A

    2010-06-15

    We used hydrophilic polymers from diapers to aid the establishment of an indigenous plant (Spergularia purpurea (Persoon) G. Don fil.) in a soil from a pyrite mine. Lysimeters were filled with the mine soil with no amendment (control), with a polyacrylate polymer, with a polymer removed from diapers, and with shredded diapers. The establishment of a plant cover was faster in soil amended with polymer from diapers, and 85 days after sowing the soil was completely covered in all treatments except control. The concentrations of trace elements in plant shoots decreased in amended soil. The activities of soil acid phosphatase, beta-glucosidase, protease and cellulase were greatest in soil amended with the polyacrylate polymer or with polymer removed from diapers, while the application of shredded diapers leads to values that were in general intermediate between these treatments and unamended control. Basal- and substrate-induced respirations, and dehydrogenase were greatest in soil amended with polymers, but the presence of a plastic film and fibrous materials from shredded diapers prevented any improvement in these parameters compared with unamended soil. In the second experiment, we evaluated the risk of downward movement of polymers in columns of a sandy soil. Polymer from diapers, with or without Cu, was placed at a 10 cm-depth. Five leaching cycles with artificial rain took place and leachates were analyzed for organic matter and Cu. At the end of the experiment, the soil columns were sliced and each layer was analyzed separately. Some repacking of soil and polymer particles took place, but there was no indication that polymers moved to any great depth in soil columns. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Cell wall polysaccharides of Chinese Wolfberry (Lycium barbarum) : Part 1. Characterisation of soluble and insoluble polymer fractions

    NARCIS (Netherlands)

    Redgwell, Robert J.; Curti, Delphine; Wang, Juankuan; Dobruchowska, Justyna M.; Gerwig, Gerrit J.; Kamerling, Johannis P.; Bucheli, Peter

    2011-01-01

    Water-soluble polysaccharides (WSP) and insoluble cell wall material (CWM) were isolated from Wolfberry fruit (Lycium barbarum). WSP were fractionated by treatment with a quaternary ammonium salt and anion-exchange chromatography. Pectic polysaccharides were major components but a glucan, xylan and

  10. Surface Hydrophilicity of Poly(l-Lactide Acid Polymer Film Changes the Human Adult Adipose Stem Cell Architecture

    Directory of Open Access Journals (Sweden)

    Chiara Argentati

    2018-02-01

    Full Text Available Current knowledge indicates that the molecular cross-talk between stem cells and biomaterials guides the stem cells’ fate within a tissue engineering system. In this work, we have explored the effects of the interaction between the poly(l-lactide acid (PLLA polymer film and human adult adipose stem cells (hASCs, focusing on the events correlating the materials’ surface characteristics and the cells’ plasma membrane. hASCs were seeded on films of pristine PLLA polymer and on a PLLA surface modified by the radiofrequency plasma method under oxygen flow (PLLA+O2. Comparative experiments were performed using human bone-marrow mesenchymal stem cells (hBM-MSCs and human umbilical matrix stem cells (hUCMSCs. After treatment with oxygen-plasma, the surface of PLLA films became hydrophilic, whereas the bulk properties were not affected. hASCs cultured on pristine PLLA polymer films acquired a spheroid conformation. On the contrary, hASCs seeded on PLLA+O2 film surface maintained the fibroblast-like morphology typically observed on tissue culture polystyrene. This suggests that the surface hydrophilicity is involved in the acquisition of the spheroid conformation. Noteworthy, the oxygen treatment had no effects on hBM-MSC and hUCMSC cultures and both stem cells maintained the same shape observed on PLLA films. This different behavior suggests that the biomaterial-interaction is stem cell specific.

  11. On the stability of the polymer brushes formed by adsorption of ionomer complexes on hydrophilic and hydrophobic surfaces.

    Science.gov (United States)

    Brzozowska, A M; Spruijt, E; de Keizer, A; Cohen Stuart, M A; Norde, W

    2011-01-15

    We have studied the effect of normal forces and shear forces on the stability and functionality of a polymer brush layer formed upon adsorption of polymeric micelles on hydrophilic and hydrophobic surfaces. The micelles consist of oppositely charged polyelectrolyte blocks (poly(acrylic acid) and poly(N-methyl 2-vinyl pyridinium iodide), and a neutral block (poly(vinyl alcohol)) or neutral grafts (poly(ethylene oxide)). The strength of the attachment of the micellar layers to various substrates was evaluated with Atomic Force Microscopy. Flow cell experiments allowed for the evaluation of long-term stability of coatings in lateral flow. Fixed angle optical reflectometry was used to quantify protein (BSA) adsorption on the micellar layers after their exposure to flow. The results show that adsorbed micellar layers are relatively weakly attached to hydrophobic surfaces and much stronger to hydrophilic surfaces, which has a significant impact on their stability. Adsorbed layers maintain their ability to suppress protein adsorption on hydrophilic surfaces but not on hydrophobic surfaces. Due to the relatively weak attachment to hydrophobic surfaces the structure of adsorbed layers may easily be disrupted by lateral forces, such that the complex coacervate-brush structure no longer exists. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Hydrophilic Hollow Molecularly Imprinted Polymer Microparticles with Photo- and Thermoresponsive Template Binding and Release Properties in Aqueous Media.

    Science.gov (United States)

    Li, Chenxi; Ma, Yue; Niu, Hui; Zhang, Huiqi

    2015-12-16

    A facile, general, and efficient approach to prepare hydrophilic hollow molecularly imprinted polymer (MIP) microparticles with photo- and thermoresponsive template binding and release behaviors in aqueous media is described, which includes the preparation of uniform "living" silica submicrospheres bearing surface atom transfer radical polymerization (ATRP)-initiating groups (i.e., alkyl halide groups) via a one-pot sol-gel method, their subsequent grafting of azobenzene (azo)-containing MIP shell and poly(N-isopropylacrylamide)-block-poly(2-hydroxyethyl methacrylate) (PNIPAAm-b-PHEMA) brushes via successive surface-initiated ATRP, and final removal of the silica core. The successful synthesis of such hydrophilic hollow MIP microparticles was confirmed with SEM, FT-IR, water dispersion stability, and static contact angle studies. They proved to show apparently higher template binding capacities than the corresponding solid ones and obvious photo- and thermoresponsive template binding properties in aqueous solutions. Moreover, their pronounced light- and temperature-controlled template release in aqueous media was also demonstrated. In particular, the introduction of PNIPAAm-b-PHEMA brushes onto hollow MIP microparticles imparted them with high surface hydrophilicity both below and above the lower critical solution temperature of PNIPAAm, which paves the way for their applications in such areas as controlled drug/chemical delivery and smart bioanalysis.

  13. Surface modification of imprinted polymer microspheres with ultrathin hydrophilic shells to improve selective recognition of glutathione in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Song, Renyuan, E-mail: songrenyuan0726@163.com; Hu, Xiaoling; Guan, Ping; Li, Ji; Du, Chunbao; Qian, Liwei; Wang, Chaoli

    2016-03-01

    A universal, effective approach addressing the classical limitations of hydrophobic molecularly imprinted polymer (MIP) microspheres was described. Two water-compatible MIP microspheres with ultrathin hydrophilic shells were synthesized by controllable surface-graft polymerization using a charged monomer (methacrylic acid) and uncharged monomer (N-isopropylacrylamide) as the hydrophilic functional monomers for the recognition of glutathione in the aqueous medium. The morphological and chemical characteristics of the as-prepared water-compatible MIP microspheres were investigated by scanning electron microscopy, Fourier transform infrared spectroscopy and contact angle measurements. Their selective recognition properties were investigated by static binding tests and compared with those of the ungrafted MIP microspheres. The results of this study showed that the both as-prepared water-compatible MIP microspheres effectively decreased non-specific binding and enhanced the imprinting factor significantly, and the water-compatible MIP microspheres prepared using N-isopropylacrylamide as monomer exhibited a more remarkable recognition property. In addition, the thickness of surface-grafted hydrophilic layer was well controlled by adjusting the irradiation time to obtain the excellent recognition property. Finally, the applicability of the as-prepared water-compatible MIP microspheres as solid-phase extraction materials was investigated by competitive binding tests using a mixture of glutathione and its analogs. - Highlights: • Ultrathin hydrophilic shell was synthesized by controllable SIP approach. • Low nonspecific binding, high imprinting factor and selectivity were achieved. • Value of imprinting factor was controlled by adjusting irradiation time. • Selective solid-phase extraction of glutathione from a mixed solution of peptides.

  14. Surface hydrophilic modification with a sugar moiety for a uniform-sized polymer molecularly imprinted for phenobarbital in serum.

    Science.gov (United States)

    Hua, Kuichang; Zhang, Lei; Zhang, Zhenhui; Guo, Yong; Guo, Tianying

    2011-08-01

    A uniform-sized polymer molecularly imprinted for phenobarbital, which is surface modified by a sugar moiety, has been prepared through a two-step swelling polymerization method using polystyrene beads as seeds, phenobarbital as the template, 4-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as a cross-linker and 2-O-meth-acryloyloxyethoxyl-(2,3,4,6- tetra-O-acetyl-β-d-galactopyranosyl)-(1-4)-2,3,6-tri-O-acetyl-β-d-glucopyranoside as a surface-modifying glycomonomer, respectively. After deprotecting the glycopolymer, a surface sugar moiety-modified, hydrophilic, molecularly imprinted polymer for phenobarbital (glyco-MIP) was obtained. The resulting polymer beads were packed into a stainless steel column to evaluate their chromatographic characteristics by high-performance liquid chromatography (HPLC). Good selectivity for phenobarbital was obtained with the glyco-MIP compared to the unmodified molecularly imprinted polymer, which revealed that the recognition sites of phenobarbital were unchanged with sugar moiety surface modification. Furthermore, bovine serum albumin was almost completely recovered from the glyco-MIP column, which indicates that the glyco-MIP materials can be used to separate and analyze drugs in complex samples, such as biological samples. The results of pretreatment with and analysis of phenobarbital in serum suggest that this material can be used to analyze phenobarbital in serum through a pretreatment and reverse-phase HPLC analysis process. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. Restricted access molecularly imprinted polymers obtained by bovine serum albumin and/or hydrophilic monomers' external layers: a comparison related to physical and chemical properties.

    Science.gov (United States)

    Santos, Mariane Gonçalves; Moraes, Gabriel de Oliveira Isac; Nakamura, Maurício Gustavo; dos Santos-Neto, Álvaro José; Figueiredo, Eduardo Costa

    2015-11-21

    Molecularly imprinting polymers (MIPs) can be modified with external layers in order to obtain restricted access molecularly imprinted polymers (RAMIPs) able to exclude macromolecules and retain low weight compounds. These modifications have been frequently achieved using hydrophilic monomers, chemically bound on the MIP surface. Recently, our group proposed a new biocompatible RAMIP based on the formation of a bovine serum albumin coating on the surface of MIP particles. This material has been used to extract drugs directly from untreated human plasma samples, but its physicochemical evaluation has not been carried out yet, mainly in comparison with RAMIPs obtained by hydrophilic monomers. Thus, we proposed in this paper a comparative study involving the surface composition, microscopic aspect, selectivity, binding kinetics, adsorption and macromolecule elimination ability of these different materials. We concluded that the synthesis procedure influences the size and shape of particles and that hydrophilic co-monomer addition as well as coating with BSA do not alter the chemical recognition ability of the material. The difference between imprinted and non-imprinted polymers' adsorption was evident (suggesting that imprinted polymers have a better capacity to bind the template than the non-imprinted ones). The Langmuir model presents the best fit to describe the materials' adsorption profile. The polymer covered with hydrophilic monomers presented the best adsorption for the template in an aqueous medium, probably due to a hydrophilic layer on its surface. We also concluded that an association of the hydrophilic monomers with the bovine serum albumin coating is important to obtain materials with higher capacity of macromolecule exclusion.

  16. Dispersing hydrophilic nanoparticles in hydrophobic polymers: HDPE/ZnO nanocomposites by a novel template-based approach

    Directory of Open Access Journals (Sweden)

    G. Filippone

    2014-05-01

    Full Text Available The efficiency of a novel template-based approach for the dispersion of hydrophilic nanoparticles within hydrophobic polymer matrices is investigated. The procedure envisages the permeation of a well dispersed nanoparticle suspension inside a micro-porous matrix, obtained through selective extraction of a sacrificial phase from a finely interpenetrated co-continuous polymer blend. Specifically, a blend of high density polyethylene (HDPE and polyethylene oxide (PEO at 50/50 wt% is prepared by melt mixing. The addition of small amounts of organo-clay promotes the necessary refinement of the blend morphology. Once removed the PEO, the micro-porous HDPE matrix is dipped in a colloidal suspension of zinc oxide nanoparticles which exhibits low interfacial tension with HDPE. A system prepared by traditional melt mixing is used as reference. Melt- and solid-state viscoelastic measurements reveal a good quality of the filler dispersion despite the uneven distribution on micro-scale. The latter can be capitalized to minimize the filler content to attain a certain improvement of the material properties or to design nano-structured polymer composites.

  17. Designing Solvent Exchange-Induced In Situ Forming Gel from Aqueous Insoluble Polymers as Matrix Base for Periodontitis Treatment.

    Science.gov (United States)

    Srichan, Tharatree; Phaechamud, Thawatchai

    2017-01-01

    An in situ forming gel is a dosage form which is promised for site-specific therapy such as periodontal pocket of periodontitis treatment. Ethylcellulose, bleached shellac, and Eudragit RS were applied in this study as a polymeric matrix for in situ forming gel employing N-methyl pyrrolidone (NMP) as solvent. Solutions comprising ethylcellulose, bleached shellac, and Eudragit RS in NMP were evaluated for viscosity, rheology, and rate of water penetration. Ease of administration by injection was determined as the force required to expel polymeric solutions through a needle using texture analyzer. In vitro gel formation and in vitro gel degradation were conducted after injection into phosphate buffer solution pH 6.8. Ethylcellulose, bleached shellac, and Eudragit RS could form the in situ gel, in vitro. Gel viscosity and pH value depended on percentage amount of the polymer, whereas the water diffusion at early period likely relied on types of polymer. Furthermore, the solutions containing higher polymer concentration exhibited the lower degree of degradation. All the preparations were acceptable as injectable dosage forms because the applied force was lower than 50 N. All of them inhibited Staphylococcus aureus, Escherichia coli, Candida albicans, Streptococcus mutans, and Porphyrommonas gingivalis growth owing to antimicrobial activity of NMP which exhibited a potential use for periodontitis treatment. Moreover, the developed systems presented as the solvent exchange induced in situ forming gel and showed capability to be incorporated with the suitable antimicrobial active compounds for periodontitis treatment which should be further studied.

  18. Soluble vs. insoluble fiber

    Science.gov (United States)

    Insoluble vs. soluble fiber; Fiber - soluble vs. insoluble ... There are 2 different types of fiber -- soluble and insoluble. Both are important for health, digestion, and preventing diseases. Soluble fiber attracts water and turns to gel during digestion. This slows ...

  19. Functionalization of a Hydrophilic Commercial Membrane Using Inorganic-Organic Polymers Coatings for Membrane Distillation

    Directory of Open Access Journals (Sweden)

    Lies Eykens

    2017-06-01

    Full Text Available Membrane distillation is a thermal separation technique using a microporous hydrophobic membrane. One of the concerns with respect to the industrialization of the technique is the development of novel membranes. In this paper, a commercially available hydrophilic polyethersulfone membrane with a suitable structure for membrane distillation was modified using available hydrophobic coatings using ORMOCER® technology to obtain a hydrophobic membrane that can be applied in membrane distillation. The surface modification was performed using a selection of different components, concentrations, and application methods. The resulting membranes can have two hydrophobic surfaces or a hydrophobic and hydrophilic surface depending on the application method. An extensive characterization procedure confirmed the suitability of the coating technique and the obtained membranes for membrane distillation. The surface contact angle of water could be increased from 27° up to 110°, and fluxes comparable to membranes commonly used for membrane distillation were achieved under similar process conditions. A 100 h test demonstrated the stability of the coating and the importance of using sufficiently stable base membranes.

  20. Asymmetric electrostatic and hydrophobic-hydrophilic interaction forces between mica surfaces and silicone polymer thin films.

    Science.gov (United States)

    Donaldson, Stephen H; Das, Saurabh; Gebbie, Matthew A; Rapp, Michael; Jones, Louis C; Roiter, Yuri; Koenig, Peter H; Gizaw, Yonas; Israelachvili, Jacob N

    2013-11-26

    We have synthesized model hydrophobic silicone thin films on gold surfaces by a two-step covalent grafting procedure. An amino-functionalized gold surface reacts with monoepoxy-terminated polydimethylsiloxane (PDMS) via a click reaction, resulting in a covalently attached nanoscale thin film of PDMS, and the click chemistry synthesis route provides great selectivity, reproducibility, and stability in the resulting model hydrophobic silicone thin films. The asymmetric interaction forces between the PDMS thin films and mica surfaces were measured with the surface forces apparatus in aqueous sodium chloride solutions. At an acidic pH of 3, attractive interactions are measured, resulting in instabilities during both approach (jump-in) and separation (jump-out from adhesive contact). Quantitative analysis of the results indicates that the Derjaguin-Landau-Verwey-Overbeek theory alone, i.e., the combination of electrostatic repulsion and van der Waals attraction, cannot fully describe the measured forces and that the additional measured adhesion is likely due to hydrophobic interactions. The surface interactions are highly pH-dependent, and a basic pH of 10 results in fully repulsive interactions at all distances, due to repulsive electrostatic and steric-hydration interactions, indicating that the PDMS is negatively charged at high pH. We describe an interaction potential with a parameter, known as the Hydra parameter, that can account for the extra attraction (low pH) due to hydrophobicity as well as the extra repulsion (high pH) due to hydrophilic (steric-hydration) interactions. The interaction potential is general and provides a quantitative measure of interfacial hydrophobicity/hydrophilicity for any set of interacting surfaces in aqueous solution.

  1. Tuning of polymeric nanoparticles by coassembly of thermoresponsive polymers and a double hydrophilic thermoresponsive block copolymer

    Czech Academy of Sciences Publication Activity Database

    Zhang, Q.; Voorhaar, L.; Filippov, Sergey K.; Yesil, B. F.; Hoogenboom, R.

    2016-01-01

    Roč. 120, č. 20 (2016), s. 4635-4643 ISSN 1520-6106 R&D Projects: GA ČR(CZ) GC15-10527J Institutional support: RVO:61389013 Keywords : nanoparticles * thermoresponsive polymers * self-assembly Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.177, year: 2016

  2. Efficient one-pot synthesis of hydrophilic and fluorescent molecularly imprinted polymer nanoparticles for direct drug quantification in real biological samples.

    Science.gov (United States)

    Niu, Hui; Yang, Yaqiong; Zhang, Huiqi

    2015-12-15

    Efficient one-pot synthesis of hydrophilic and fluorescent molecularly imprinted polymer (MIP) nanoparticles and their application as optical chemosensor for direct drug quantification in real, undiluted biological samples are described. The general principle was demonstrated by preparing tetracycline (Tc, a broad-spectrum antibiotic)-imprinted fluorescent polymer nanoparticles bearing hydrophilic polymer brushes via poly(2-hydroxyethyl methacrylate) (PHEMA) macromolecular chain transfer agent-mediated reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization in the presence of a fluorescent monomer. The introduction of hydrophilic PHEMA brushes and fluorescence labeling onto/into the MIP nanoparticles proved to not only significantly improve their surface hydrophilicity and lead to their obvious specific binding and high selectivity toward Tc in the undiluted bovine serum, but also impart them with strong fluorescent properties. In particular, significant fluorescence quenching was observed upon their binding with Tc in such complex biological milieu, which makes these Tc-MIP nanoparticles useful optical chemosensor with a detection limit of 0.26 μM. Furthermore, such advanced functional MIP nanoparticles-based chemosensor was also successfully utilized for the direct, sensitive, and accurate determination of Tc in another biological medium (i.e., the undiluted pig serum) with average recoveries ranging from 98% to 102%, even in the presence of several interfering drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Soil quality indicators response to application of hydrophilic polymers to a soil from a sulfide mine.

    Science.gov (United States)

    de Varennes, A; Qu, G; Cordovil, C; Gonçalves, P

    2011-09-15

    In soils impacted by mining activities a vegetal cover is required to protect the site from the erosive forces of water and wind. The success of this objective depends on plant establishment and canopy closure. Polyacryalate polymers aid the growth of crops and indigenous plants in soils from sulfide mines. Soil characteristics change as a consequence of polymer application, but indicators that pinpoint these changes have not been identified yet. Our objectives were to (1) identify the sensitive indicators of changes in soil quality following polymer application, (2) relate these with assessment based on plant growth and soil cover. A mine soil was left unamended or received a characterized polyacrylate, a polyacrylate removed from diapers, or shredded diapers. Biomass of Spergularia purpurea was measured and proportion of soil cover evaluated. Soil enzymes, microbial activity, and respiration were analyzed. Availability of potentially toxic trace elements was estimated by their concentration in shoots. Factor analysis identified three factors that accounted for 94% of the variation in parameters, and the scores separated the four treatments. The indicators with greatest communality were correlated with plant growth and soil cover. The best soil quality indicators were As and Zn in shoots, protease, β-glucosidase, and fructose-induced respiration. It seems that the most important indicators to be used to assess the restoration of sulfide mine soils are those related with bioavailability of trace elements and soil enzymatic activities. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Fluorescent graphene oxide via polymer grafting: an efficient nanocarrier for both hydrophilic and hydrophobic drugs.

    Science.gov (United States)

    Kundu, Aniruddha; Nandi, Sudipta; Das, Pradip; Nandi, Arun K

    2015-02-18

    Functionalized graphene-based drug delivery vehicles have conquered a significant position because functionalization improves its biocompatibility and stability in cell medium, leaving sufficient graphitic basal plane for drug loading through π-π stacking. In this study, poly(N-isopropylacrylamide) (PNIPAM) is covalently grafted from the surface of graphene oxide (GO) via a facile, eco-friendly and an easy procedure of free radical polymerization (FRP) using ammonium persulfate initiator. Various spectroscopic and microscopic studies confirm the successful grafting of PNIPAM from GO surface. PNIPAM-grafted GO (GPNM) exhibits enhanced thermal stability, improved dispersibility both in aqueous and cell medium, and better biocompatibility and cell viability compared to GO. Interestingly, GPNM displays an exciting fluorescence property in aqueous medium, which is a hike of intensity at 36 °C due to the lower critical solution temperature (LCST) of PNIPAM chains (32 °C). Moreover both hydrophilic (doxorubicin (DOX)) and hydrophobic (indomethacin (IMC)) drugs loaded on the surface of GPNM hybrid exhibits its efficacy as an efficient carrier for both types of drugs. Cellular uptakes of free DOX and DOX-loaded GPNM (GPNM-DOX) are evidenced both from optical and fluorescence imaging of live cells, and the efficiency of drug is significantly improved in the loaded system. The release of DOX from GPNM-DOX was achieved at pH 4, relevant to the environment of cancer cells. The pH-triggered release of hydrophobic drug was also studied using UV-vis spectroscopy via alginate encapsulation, showing a great enhancement at pH = 7.4. The IMC is also found to be released by human serum albumin using dialysis technique. The GPNM nanomaterial shows the property of simultaneous loading of DOX and IMC as well as pH-triggered simultaneous release of both of the drugs.

  5. Charged hydrophilic polymer brushes and their relevance for understanding marine biofouling.

    Science.gov (United States)

    Yandi, Wetra; Mieszkin, Sophie; di Fino, Alessio; Martin-Tanchereau, Pierre; Callow, Maureen E; Callow, James A; Tyson, Lyndsey; Clare, Anthony S; Ederth, Thomas

    2016-07-01

    The resistance of charged polymers to biofouling was investigated by subjecting cationic (PDMAEMA), anionic (PSPMA), neutral (PHEMA-co-PEG10MA), and zwitterionic (PSBMA) brushes to assays testing protein adsorption; attachment of the marine bacterium Cobetia marina; settlement and adhesion strength of zoospores of the green alga Ulva linza; settlement of barnacle (Balanus amphitrite and B. improvisus) cypris larvae; and field immersion tests. Several results go beyond the expected dependence on direct electrostatic attraction; PSPMA showed good resistance towards attachment of C. marina, low settlement and adhesion of U. linza zoospores, and significantly lower biofouling than on PHEMA-co-PEG10MA or PSBMA after a field test for one week. PDMAEMA showed potential as a contact-active anti-algal coating due to its capacity to damage attached spores. However, after field testing for eight weeks, there were no significant differences in biofouling coverage among the surfaces. While charged polymers are unsuitable as antifouling coatings in the natural environment, they provide valuable insights into fouling processes, and are relevant for studies due to charging of nominally neutral surfaces.

  6. Inactivation of pulmonary surfactant due to serum-inhibited adsorption and reversal by hydrophilic polymers: experimental

    DEFF Research Database (Denmark)

    Taeusch, H William; de la Serna, Jorge Bernardino; Perez-Gil, Jesus

    2005-01-01

    increases in pi did not occur when surfactants were applied to subphases containing serum. Components of serum are surface active and adsorb reversibly to the interface increasing pi up to a concentration-dependent saturation value, pi(max). When surfactants were applied to subphases containing serum......The rate of change of surface pressure, pi, in a Langmuir trough following the deposition of surfactant suspensions on subphases containing serum, with or without polymers, is used to model a likely cause of surfactant inactivation in vivo: inhibition of surfactant adsorption due to competitive...... adsorption of surface active serum proteins. Aqueous suspensions of native porcine surfactant, organic extracts of native surfactant, and the clinical surfactants Curosurf, Infasurf, and Survanta spread on buffered subphases increase the surface pressure, pi, to approximately 40 mN/m within 2 min...

  7. Effect of different polymers and their combinations on the release of metoclopramide HCl from sustained-release hydrophilic matrix tablets.

    Science.gov (United States)

    Savaşer, Ayhan; Taş, Çetin; Bayrak, Ziya; Özkan, Cansel Köse; Özkan, Yalçın

    2013-01-01

    Metoclopramide HCl (MTC) is commonly used for the management of gastrointestinal disorders. It has a short biological half-life and is usually administered four times daily to maintain effective concentrations throughout the day. The aim of this study is to develop sustained-release hydrophilic matrix tablet formulations of drug to achieve reproducible and predictable release rates, extended duration of activity, decreased toxicity, reduction of required dose, optimized therapy, and improved patient compliance. Hydroxypropylmethyl cellulose (HPMC), carboxymethylcellulose sodium (NaCMC), chitosan and Carbopol 981 were incorporated in the matrix system separately or in combinations as release controlling factor by direct compression technique. Compatibility among the formulation components was assessed by DSC and FTIR analysis. MTC release from matrix was evaluated by using the US Pharmacopeia dissolution apparatus II. All formulations met the criteria of pharmacopeial requirements. Dissolution studies show that polymer type and concentration are important parameters on drug release. Chitosan, carbopol and NaCMC formulations exhibited pH-dependent drug release profile whereas HPMC did not. All the formulations containing 1:1 ratio of HPMC and chitosan exhibited desired drug release showing that all active substance releases progressively in a period of whole dissolution time and therefore it can be regarded as worthy of consideration for the manufacture of sustained-release MTC product.

  8. Rapid Hydrophilization of Model Polyurethane/Urea (PURPEG Polymer Scaffolds Using Oxygen Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Rok Zaplotnik

    2016-04-01

    Full Text Available Polyurethane/urea copolymers based on poly(ethylene glycol (PURPEG were exposed to weakly ionized, highly reactive low-pressure oxygen plasma to improve their sorption kinetics. The plasma was sustained with an inductively coupled radiofrequency generator operating at various power levels in either E-mode (up to the forward power of 300 W or H-mode (above 500 W. The treatments that used H-mode caused nearly instant thermal degradation of the polymer samples. The density of the charged particles in E-mode was on the order of 1016 m−3, which prevented material destruction upon plasma treatment, but the density of neutral O-atoms in the ground state was on the order of 1021 m−3. The evolution of plasma characteristics during sample treatment in E-mode was determined by optical emission spectroscopy; surface modifications were determined by water adsorption kinetics and X-ray photoelectron spectroscopy; and etching intensity was determined by residual gas analysis. The results showed moderate surface functionalization with hydroxyl and carboxyl/ester groups, weak etching at a rate of several nm/s, rather slow activation down to a water contact angle of 30° and an ability to rapidly absorb water.

  9. Use of hydrophilic and hydrophobic polymers for the development of controlled release tizanidine matrix tablets

    Directory of Open Access Journals (Sweden)

    Tariq Ali

    2014-12-01

    Full Text Available The aim of the present study was to develop tizanidine controlled release matrix. Formulations were designed using central composite method with the help of design expert version 7.0 software. Avicel pH 101 in the range of 14-50% was used as a filler, while HPMC K4M and K100M in the range of 25-55%, Ethylcellulose 10 ST and 10FP in the range of 15 - 45% and Kollidon SR in the range of 25-60% were used as controlled release agents in designing different formulations. Various physical parameters including powder flow for blends and weight variation, thickness, hardness, friability, disintegration time and in-vitro release were tested for tablets. Assay of tablets were also performed as specified in USP 35 NF 32. Physical parameters of both powder blend and compressed tablets such as compressibility index, angle of repose, weight variation, thickness, hardness, friability, disintegration time and assay were evaluated and found to be satisfactory for formulations K4M2, K4M3, K4M9, K100M2, K100M3, K100M9, E10FP2, E10FP9, KSR2, KSR3 & KSR9. In vitro dissolution study was conducted in 900 ml of 0.1N HCl, phosphate buffer pH 4.5 and 6.8 medium using USP Apparatus II. In vitro release profiles indicated that formulations prepared with Ethocel 10 standard were unable to control the release of drug while formulations K4M2, K100M9, E10FP2 & KSR2 having polymer content ranging from 40-55% showed a controlled drug release pattern in the above mentioned medium. Zero-order drug release kinetics was observed for formulations K4M2, K100M9, E10FP2 & KSR2. Similarity test (f2 results for K4M2, E10FP2 & KSR2 were found to be comparable with reference formulation K100M9. Response Surface plots were also prepared for evaluating the effect of independent variable on the responses. Stability study was performed as per ICH guidelines and the calculated shelf life was 24-30 months for formulation K4M2, K100M9 and E10FP2.

  10. One-pot synthesis of quantum dot-labeled hydrophilic molecularly imprinted polymer nanoparticles for direct optosensing of folic acid in real, undiluted biological samples.

    Science.gov (United States)

    Yang, Yaqiong; Wang, Zhengzheng; Niu, Hui; Zhang, Huiqi

    2016-12-15

    A facile and efficient one-pot approach for the synthesis of quantum dot (QD)-labeled hydrophilic molecularly imprinted polymer (MIP) nanoparticles for direct optosensing of folic acid (FA) in the undiluted bovine and porcine serums is described. Hydrophilic macromolecular chain transfer agent-mediated reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization was used to implement the molecular imprinting of FA in the presence of CdTe quantum dots (QDs). The resulting FA-imprinted polymer nanoparticles with surface-grafted hydrophilic poly(glyceryl monomethacrylate) brushes and QDs labeling not only showed outstanding specific molecular recognition toward FA in biological samples, but also exhibited good photostability, rapid binding kinetics, and obvious template binding-induced fluorescence quenching. These characteristics make them a useful fluorescent chemosensor for directly and selectively optosensing FA in the undiluted bovine and porcine serums, with its limit of detection being 0.025μM and average recoveries ranging from 98% to 102%, even in the presence of several interfering compounds. This advanced fluorescent MIP chemosensor is highly promising for rapid quantification of FA in such applications as clinical diagnostics and food analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. The expression of a xylanase targeted to ER-protein bodies provides a simple strategy to produce active insoluble enzyme polymers in tobacco plants.

    Directory of Open Access Journals (Sweden)

    Immaculada Llop-Tous

    Full Text Available BACKGROUND: Xylanases deserve particular attention due to their potential application in the feed, pulp bleaching and paper industries. We have developed here an efficient system for the production of an active xylanase in tobacco plants fused to a proline-rich domain (Zera of the maize storage protein γ-zein. Zera is a self-assembling domain able to form protein aggregates in vivo packed in newly formed endoplasmic reticulum-derived organelles known as protein bodies (PBs. METHODOLOGY/PRINCIPAL FINDINGS: Tobacco leaves were transiently transformed with a binary vector containing the Zera-xylanase coding region, which was optimized for plant expression, under the control of the 35S CaMV promoter. The fusion protein was efficiently expressed and stored in dense PBs, resulting in yields of up to 9% of total protein. Zera-xylanase was post-translationally modified with high-mannose-type glycans. Xylanase fused to Zera was biologically active not only when solubilized from PBs but also in its insoluble form. The resistance of insoluble Zera-xylanase to trypsin digestion demonstrated that the correct folding of xylanase in PBs was not impaired by Zera oligomerization. The activity of insoluble Zera-xylanase was enhanced when substrate accessibility was facilitated by physical treatments such as ultrasound. Moreover, we found that the thermostability of the enzyme was improved when Zera was fused to the C-terminus of xylanase. CONCLUSION/SIGNIFICANCE: In the present work we have successfully produced an active insoluble aggregate of xylanase fused to Zera in plants. Zera-xylanase chimeric protein accumulates within ER-derived protein bodies as active aggregates that can easily be recovered by a simple density-based downstream process. The production of insoluble active Zera-xylanase protein in tobacco outlines the potential of Zera as a fusion partner for producing enzymes of biotechnological relevance. Zera-PBs could thus become efficient and low

  12. Water vapor exchange system using a hydrophilic microporous layer coated gas diffusion layer to enhance performance of polymer electrolyte fuel cells without cathode humidification

    Science.gov (United States)

    Kitahara, Tatsumi; Nakajima, Hironori; Morishita, Masashi

    2012-09-01

    Polymer electrolyte fuel cells (PEFCs) generally have external humidifiers to supply humidified hydrogen and oxidant gases, which prevents dehydration of the membrane. If a PEFC could be operated without humidification, then external humidifiers could be removed, which would result in a simplified PEFC system with increased total efficiency and reduced cost. A water vapor exchange system installed in the PEFC was developed to enhance the performance without cathode humidification. A gas diffusion layer (GDL) coated with a hydrophobic microporous layer (MPL) was used at the active reaction area. A GDL coated with a hydrophilic MPL consisting of polyvinyl alcohol (PVA) and carbon black was used at the cathode water vapor exchange area to promote water transport from the cathode outlet wet gas to the anode inlet dry gas. This is effective for reducing the IR overpotential, which enhances the PEFC performance. Appropriate enhancement of hydrophilicity by increasing the PVA content in the MPL to 20 mass% is effective to increase water transport from the cathode to anode. At the anode water exchange area, a GDL without the hydrophilic MPL is effective to promote water transport from the water exchange area to the active reaction area, which enhances the PEFC performance.

  13. High Temperature, Low Relative Humidity, Polymer-type Membranes Based on Disulfonated Poly(arylene ether) Block and Random Copolymers Optionally Incorporating Protonic Conducting Layered Water insoluble Zirconium Fillers

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, James E.; Baird, Donald G.

    2010-06-03

    Our research group has been engaged in the past few years in the synthesis of biphenol based partially disulfonated poly(arylene ether sulfone) random copolymers as potential PEMs. This series of polymers are named as BPSH-xx, where BP stands for biphenol, S stands for sulfonated, H stands for acidified and xx represents the degree of disulfonation. All of these sulfonated copolymers phase separate to form nano scale hydrophilic and hydrophobic morphological domains. The hydrophilic phase containing the sulfonic acid moieties causes the copolymer to absorb water. Water confined in hydrophilic pores in concert with the sulfonic acid groups serve the critical function of proton (ion) conduction and water transport in these systems. Both Nafion and BPSH show high proton conductivity at fully hydrated conditions. However proton transport is especially limited at low hydration level for the BPSH random copolymer. It has been observed that the diffusion coefficients of both water and protons change with the water content of the pore. This change in proton and water transport mechanisms with hydration level has been attributed to the solvation of the acid groups and the amount of bound and bulk-like water within a pore. At low hydration levels most of the water is tightly associated with sulfonic groups and has a low diffusion coefficient. This tends to encourage isolated domain morphology. Thus, although there may be significant concentrations of protons, the transport is limited by the discontinuous morphological structure. Hence the challenge lies in how to modify the chemistry of the polymers to obtain significant protonic conductivity at low hydration levels. This may be possible if one can alter the chemical structure to synthesize nanophase separated ion containing block copolymers. Unlike the BPSH copolymers, where the sulfonic acid groups are randomly distributed along the chain, the multiblock copolymers will feature an ordered sequence of hydrophilic and

  14. Formulation and evaluation of carvedilol melt-in-mouth tablet using mucoadhesive polymer and PEG-6-stearate as hydrophilic waxy binder.

    Science.gov (United States)

    Dangi, Amish Ashvinkumar; Zalodiya, Prakash Bhikhabhai

    2012-10-01

    The demand for melt-in-mouth tablets (MMTs) has been rapidly growing during the last decade, especially for the elderly and children who have swallowing difficulties, to avoid first-pass metabolism and quick drug entry into the systemic circulation. In this work, a new approach has been tried to prepare MMTs using a hydrophilic waxy binder [polyethylene glycol (PEG)-6-stearate]. Carvedilol MMTs were prepared by direct compression method using different mucoadhesive polymers such as hydroxypropyl methylcellulose (HPMC), chitosan, and sodium carboxymethyl cellulose (Na-CMC) at various concentrations (range: 0.5-5%) to reduce the flushing action of saliva and to increase mucosal absorption. All the formulations were evaluated for various physiochemical parameters, and the formulations containing the maximum amount of polymer (F4, F7, and F10) were selected for further stability study. The deaggregation time of the tablets was found to be rapid, and the dissolution test revealed that carvedilol was dissolved from the formulation within the compendia limits. This data confirmed that the polymer concentration (0.5-5%) was within acceptable limits. It was also concluded that avicel PH101, pearlitol SD 200, and croscarmellose sodium (CCS) were the appropriate excipients and formulated in the right proportion. As a result, mouth dissolving administration of carvedilol formulated with appropriate excipients and especially with chitosan seems a promising alternative to traditional routes.

  15. Tissue coverage of a hydrophilic polymer-coated zotarolimus-eluting stent vs. a fluoropolymer-coated everolimus-eluting stent at 13-month follow-up: An optical coherence tomography substudy from the RESOLUTE All Comers trial

    NARCIS (Netherlands)

    J.L. Gutiérrez-Chico; R.J.M. van Geuns (Robert Jan); E.S. Regar (Eveline); W.J. van der Giessen (Wim); H. Kelbæk (Henning); K. Saunamäki (Kari); J. Escaned (Javier); N. Gonzalo (Nieves); C. di Mario (Carlo); F. Borgia (Francesco); E. Nüesch (Eveline); H.M. Garcia-Garcia (Hector); S. Silber (Sigmund); S.W. Windecker (Stephan); P.W.J.C. Serruys (Patrick)

    2011-01-01

    textabstractAim s To compare the tissue coverage of a hydrophilic polymer-coated zotarolimus-eluting stent (ZES) vs. a fluoropolymer-coated everolimus-eluting stent (EES) at 13 months, using optical coherence tomography (OCT) in an 'all-comers population of patients, in order to clarify the

  16. Tissue coverage of a hydrophilic polymer-coated zotarolimus-eluting stent vs. a fluoropolymer-coated everolimus-eluting stent at 13-month follow-up: an optical coherence tomography substudy from the RESOLUTE All Comers trial

    DEFF Research Database (Denmark)

    Gutiérrez-Chico, Juan Luis; van Geuns, Robert Jan; Regar, Evelyn

    2011-01-01

    To compare the tissue coverage of a hydrophilic polymer-coated zotarolimus-eluting stent (ZES) vs. a fluoropolymer-coated everolimus-eluting stent (EES) at 13 months, using optical coherence tomography (OCT) in an 'all-comers' population of patients, in order to clarify the mechanism of eventual ...

  17. Size exclusion chromatography of synthetic polymers and biopolymers on common reversed phase and hydrophilic interaction chromatography columns.

    Science.gov (United States)

    Caltabiano, Anna M; Foley, Joe P; Barth, Howard G

    2016-03-11

    This work describes the applicability of common reversed phase and HILIC columns for size exclusion chromatography of synthetic and natural polymers. Depending on the nature of the solute and column stationary phase, a "non-retention" condition must be created with the aid of the mobile phase to achieve a unique size-based separation in isocratic mode. The various bonded phases show remarkable differences in size separations that are controlled by mobile phase conditions. Polymer-mobile phase and column-mobile phase solvation interactions determine polymer hydrodynamic volume (or solute bulkiness) and polymer-column steric interaction. Solvation interactions in turn depend on polymer, mobile phase and stationary phase polarities. Column-mobile phase solvation interactions determine the structural order of the bonded ligands that can vary from ordered (extended, aligned away from the silica substrate) to disordered (folded, pointing toward the silica substrate). Chain order increases with increased solvent penetration into the bonded phase. Increased chain order reduces pore volume, and therefore decreases the size-separation efficiency of a column. Conversely, decreased chain order increases pore volume and therefore increases the size-separation efficiency. The thermodynamic quality of the mobile phase also plays a significant role in the separation of polymers. "Poor" solvents can significantly reduce the hydrodynamic diameter of a solute and thus change their retention behavior. Medium polarity stationary phases, such as fluoro-phenyl and cyano, exhibit a unique retention behavior. With an appropriate polarity mobile phase, polar and non-polar synthetic polymers of the same molecular masses can be eluted at the same retention volumes. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Hydrophilic nanoporous materials

    DEFF Research Database (Denmark)

    2010-01-01

    The present application discloses a method for preparing and rendering hydrophilic a nanoporous material of a polymer matrix which has a porosity of 0.1-90 percent (v/v), such that the ratio between the final water absorption (percent (w/w)) and the porosity (percent (v/v)) is at least 0.05, the ......The present application discloses a method for preparing and rendering hydrophilic a nanoporous material of a polymer matrix which has a porosity of 0.1-90 percent (v/v), such that the ratio between the final water absorption (percent (w/w)) and the porosity (percent (v/v)) is at least 0.......05, the method comprising the steps of: (a) preparing a precursor material comprising at least one polymeric component and having a first phase and a second phase; (b) removal of at least a part of the first phase of the precursor material prepared in step (a) so as to leave behind a nanoporous material...... of the polymer matrix; (c) irradiating at least a part of said nanoporous material with light of a wave length of in the range of 250-400 nm (or 200-700 nm) in the presence of oxygen and/or ozone. Corresponding hydrophilic nanoporous materials are also disclosed. L...

  19. Surface modification of poly(ethylene terephthalate) angioplasty balloons with a hydrophilic poly(acrylamide-co-ethylene glycol) interpenetrating polymer network coating.

    Science.gov (United States)

    Park, S; Bearinger, J P; Lautenschlager, E P; Castner, D G; Healy, K E

    2000-09-01

    An interpenetrating polymer network (IPN) of poly(acrylamide-co-ethylene glycol) (p(AAm-co-EG)) hydrogel was covalently grafted to polyethylene terephthalate (PET) angioplasty balloons to increase surface hydrophilicity and improve lubricity. A 2-step graft polymerization protocol was followed to first polymerize and cross-link acrylamide onto the substrate with a photosensitizer and/or oxygen plasma pretreatment. The effects of varying photo-initiation and plasma exposure times were investigated separately and conjunctively using water contact angles to obtain optimal coating deposition parameters. A poly(ethylene glycol) network was then grafted by swelling the preexisting polyacrylamide network to allow inter-diffusion of the monomer and cross-linker, which were then polymerized by photo-initiation. When the photo-initiation time was long enough to reach near gelation, pretreatment of PET with oxygen plasma did not offer significant benefit. X-ray photoelectron spectroscopy confirmed the presence of both polymer layers, and composition depth profiles supported the assessment that an interpenetrating network was formed. Tensile testing and application of Weibull statistics on unmodified and modified films indicated that the surface modification approach did not significantly alter the mechanical integrity of the material. These findings indicate that a p(AAm-co-EG) coating can be effectively deposited on PET surfaces without compromising the structural integrity of the substrate. Copyright 2000 John Wiley & Sons, Inc.

  20. Protein Stability during Hot Melt Extrusion: The Effect of Extrusion Temperature, Hydrophilicity of Polymers and Sugar Glass Pre-stabilization

    NARCIS (Netherlands)

    Teekamp, Naomi; Olinga, Peter; Frijlink, Henderik W.; Hinrichs, Wouter

    2015-01-01

    Purpose Biodegradable polymers have been widely investigated for controlled release formulations for protein delivery. However, the processing stability of proteins remains a major challenge. The aim of this research is to assess the influence of the hot melt extrusion process on the activity of a

  1. Protein Stability during Hot Melt Extrusion : The Effect of Extrusion Temperature, Hydrophilicity of Polymers and Sugar Glass Pre-stabilization

    NARCIS (Netherlands)

    Teekamp, Naomi; Olinga, Peter; Hinrichs, Wouter; Frijlink, Henderik W.

    2015-01-01

    Purpose Biodegradable polymers have been widely investigated for controlled release formulations for protein delivery. However, the processing stability of proteins remains a major challenge. The aim of this research is to assess the influence of the hot melt extrusion process on the activity of a

  2. Enhancing water retention and low-humidity proton conductivity of sulfonated poly(ether ether ketone) composite membrane enabled by the polymer-microcapsules with controllable hydrophilicity-hydrophobicity

    Science.gov (United States)

    He, Guangwei; Li, Yifan; Li, Zongyu; Nie, Lingli; Wu, Hong; Yang, Xinlin; Zhao, Yuning; Jiang, Zhongyi

    2014-02-01

    Four kinds of polymer microcapsules (PMCs) with different hydrophilicity-hydrophobicity are synthesized via distillation-precipitation polymerization (polymer microcapsules form by self-crosslinking of monomers/crosslinkers in this process) and incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare composite membranes. To improve the water retention of the PMCs, the hydrophilicity-hydrophobicity of the PMCs is manipulated by regulating the proportion of hydrophilic ethylene glycol dimethacrylate (EGDMA) and hydrophobic divinylbenzene (DVB) crosslinkers in the synthesis formula. The hydrophilicity of the PMCs decreases with increasing the content of polyDVB in the PMCs. The four kinds of PMCs exhibit different water retention properties. The PMCs with appropriate hydrophilic/hydrophobic balance (EGDMA: DVB = 1:1) possess the best water retention properties. Incorporation of PMCs into SPEEK matrix enhances the water-retention properties, and consequently increases proton conductivity to 0.0132 S cm-1 under 20% relative humidity, about thirteen times higher than that of the SPEEK control membrane. Moreover, the incorporation of PMCs reduces the activation energy for proton conduction and the methanol permeability of the membranes. This study may be helpful to rational design of excellent water-retention materials.

  3. Investigation of the interactions of enteric and hydrophilic polymers to enhance dissolution of griseofulvin following hot melt extrusion processing.

    Science.gov (United States)

    Bennett, Ryan C; Keen, Justin M; Bi, Yunxia Vivian; Porter, Stuart; Dürig, Thomas; McGinity, James W

    2015-07-01

    This study focuses on the application of hot melt extrusion (HME) to produce solid dispersions containing griseofulvin (GF) and investigates the in-vitro dissolution performance of HME powders and resulting tablet compositions containing HME-processed dispersions. Binary, ternary and quaternary dispersions containing GF, enteric polymer (Eudragit L100-55 or AQOAT-LF) and/or vinyl pyrrolidone-based polymer (Plasdone K-12 povidone or S-630 copovidone) were processed by HME. Two plasticizers, triethyl citrate (TEC) and acetyl tributyl citrate (ATBC), were incorporated to aid in melt processing and to modify release of GF in neutral media following a pH-change in dissolution. Products were characterized for GF recovery, degrees of compositional amorphous character, intermolecular interactions and non-sink dissolution performance. Binary dispersions exhibited lower maximum observed concentration values and magnitudes of supersaturated GF in neutral media dissolution in comparison with the ternary dispersions. The quaternary HME products, 1 : 2 : 1 : 0.6 GF : L100-55 : S-630 : ATBC and GF : AQOAT-LF : K-12 : ATBC, were determined as the most optimal concentration-enhancing compositions due to increased hydrogen bonding of enteric functional groups with carbonyl/acetate groups of vinyl pyrrolidone-based polymers, reduced compositional crystallinity and presence of incorporated hydrophobic plasticizer. HME products containing combinations of concentration-enhancing polymers can supersaturate and sustain GF dissolution to greater magnitudes in neutral media following the pH-transition and be compressed into immediate-release tablets exhibiting similar dissolution profiles. © 2015 Royal Pharmaceutical Society.

  4. Effect of Plasma Gas Flow Direction on Hydrophilicity of Polymer by Small Zone Cold Plasma Treatment and Hydrophobic Plasma Treatment

    OpenAIRE

    Sheng-Hsiang Hsu; Ko-Shao Chen; Hong-Ru Lin; Shu-Ju Chang; Tzu-Piao Tang

    2009-01-01

    Plasma treatment is the most popular surface modification process of polymers. A small cold plasma zone treatment is an important modification technique in modern industry. In this study, the effect of gas flow direction on plasma treatment was investigated. In order to decrease the plasma zone area, we added a separate cylinder to surround the upper electrode. The separate cylinder is effective in limiting the plasma discharge area, and we could find a light and dark area in the vacuum chamb...

  5. From the Solution Processing of Hydrophilic Molecules to Polymer-Phthalocyanine Hybrid Materials for Ammonia Sensing in High Humidity Atmospheres

    Science.gov (United States)

    Gaudillat, Pierre; Jurin, Florian; Lakard, Boris; Buron, Cédric; Suisse, Jean-Moïse; Bouvet, Marcel

    2014-01-01

    We have prepared different hybrid polymer-phthalocyanine materials by solution processing, starting from two sulfonated phthalocyanines, s-CoPc and CuTsPc, and polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), poly(acrylic acid-co-acrylamide) (PAA-AM), poly(diallyldimethylammonium chloride) (PDDA) and polyaniline (PANI) as polymers. We also studied the response to ammonia (NH3) of resistors prepared from these sensing materials. The solvent casted films, prepared from s-CoPc and PVP, PEG and PAA-AM, were highly insulating and very sensitive to the relative humidity (RH) variation. The incorporation of s-CoPc in PDDA by means of layer-by-layer (LBL) technique allowed to stabilize the film, but was too insulating to be interesting. We also prepared PANI-CuTsPc hybrid films by LBL technique. It allowed a regular deposition as evidenced by the linear increase of the absorbance at 688 nm as a function of the number of bilayers. The sensitivity to ammonia (NH3) of PANi-CuTsPc resistors was very high compared to that of individual materials, giving up to 80% of current decrease when exposed to 30 ppm NH3. Contrarily to what happens with neutral polymers, in PANI, CuTsPc was stabilized by strong electrostatic interactions, leading to a stable response to NH3, whatever the relative humidity in the range 10%–70%. Thus, the synergy of PANI with ionic macrocycles used as counteranions combined with their simple aqueous solution processing opens the way to the development of new gas sensors capable of operating in real world conditions. PMID:25061841

  6. Development of amorphous dispersions of artemether with hydrophilic polymers via spray drying: Physicochemical and in silico studies

    Directory of Open Access Journals (Sweden)

    Jaywant N. Pawar

    2016-06-01

    Full Text Available Artemether (ARM is a poorly water soluble and poorly permeable drug effective against acute and severe falciparum malaria, hence there is a strong need to improve its solubility. The objective of the study was to enhance the solubility and dissolution rate of ARM by preparation of solid dispersions using spray-drying technique. Solid dispersions of ARM were prepared with Soluplus, Kollidon VA 64, HPMC and Eudragit EPO at weight ratios of 1:1, 1:2, 1:3 using spray drying technology, and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC, and X-ray powder diffraction (XRD to identify the physicochemical interaction between drug and carrier, as well as effect on dissolution. The prepared solid dispersion of ARM with polymers showed reduced crystallinity as compared to neat ARM, which was confirmed by DSC and XRD. Drug/polymer interactions were studied in-silico by docking and molecular dynamics which indicated formation of van der Waals type of interactions of ARM with the polymers. Based on solubility studies, the optimum drug/Soluplus ratio was found to be 1:3. The dissolution studies of formulation SD3 showed highest drug release up to 82% compared to neat ARM giving only 20% at 60 minutes. The spray-dried products were free of crystalline ARM; possessed higher dissolution rates, and were stable over a period according to ICH guidelines. These findings suggest that an amorphous solid dispersion of ARM could be a viable option for enhancing the dissolution rate of ARM.

  7. Gas diffusion layers coated with a microporous layer containing hydrophilic carbon nanotubes for performance enhancement of polymer electrolyte fuel cells under both low and high humidity conditions

    Science.gov (United States)

    Kitahara, Tatsumi; Nakajima, Hironori; Okamura, Kosuke

    2015-06-01

    Gas diffusion layers (GDLs) coated with a hydrophobic microporous layer (MPL) composed of carbon black and polytetrafluoroethylene (PTFE) have been commonly used to improve the water management characteristics of polymer electrolyte fuel cells (PEFCs). However, the hydrophobic MPL coated GDL designed to prevent dehydration of the membrane under low humidity conditions is generally inferior at reducing flooding under high humidity conditions. It is therefore important to develop a robust MPL coated GDL that can enhance the PEFC performance regardless of the humidity conditions. In the present study, a GDL coated with an MPL containing hydrophilic carbon nanotubes (CNTs) was developed. The less hydrophobic pores incorporating CNTs are effective at conserving the membrane humidity under low humidity conditions. The MPL with CNTs is also effective at expelling excess water from the catalyst layer while maintaining oxygen flow pathways from the GDL substrate, allowing the mean flow pore diameter to be decreased to 2 μm without reducing the ability of the MPL to prevent flooding under high humidity conditions. An MPL coated GDL with a CNT content of 4 mass% exhibits significantly higher performance under both low and high humidity conditions than a hydrophobic MPL coated GDL.

  8. The effective synthesis of Insoluble sulfur using electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daejin; Yu, Kookhyun [Dongguk Univ., Seoul (Korea, Republic of)

    2013-07-01

    Vulcanization is process that formed crosslinking by Insoluble sulfur between linear structure of rubber polymer. Recently, Synthesis of Insoluble sulfur is used Thermal polymerization using about 250 {approx} 300 .deg. C and extraction process is used carbon disulfide(CS2) for separation between soluble sulfur and insoluble sulfur. But this process isn't environmental, economical and safety. This research was focus on developing of insoluble sulfur synthesis process using electron beam. This new process is using under the 140 .deg. C. Because of that, explosion risk is decrease, environmental and economical factor is increased. The sulfur can be melt by increase temperature or made solution using carbon disulfide. And electron beam is irradiated melting sulfur or sulfur solution. After irradiation, The high purity insoluble sulfur can be obtained by separation with carbon disulfide.

  9. Formulation of a modified release metformin. HCl matrix tablet: influence of some hydrophilic polymers on release rate and in-vitro evaluation

    Directory of Open Access Journals (Sweden)

    John Rojas

    2011-09-01

    Full Text Available Metformin hydrochloride is an antidiabetic agent which improves glucose tolerance in patients with type 2 diabetes and reduces basal plasma levels of glucose. In this study, a simplex centroid experimental design with 69 runs was used to select the best combination of some hydrophilic polymers that rendered a 24 h in-vitro release profile of metformin.HCl. The Korsmeyer-Peppas model was used to model the dissolution profiles since it presented the best fit to the experimental data. Further, a cubic model predicted the best formulation of metformin.HCl containing polyvinyl pyrrolidone, ethyl cellulose, hydroxypropyl methyl cellulose, carrageenan, sodium alginate, and gum arabic at 6.26, 68.7, 6.26, 6.26, 6.26 and 6.26 % levels, respectively. The validation runs confirmed the accuracy of the cubic model with six components for predicting the best set of components which rendered a once-a-day modified release hydrophilic matrix tablet in compliance with the USP specifications.O cloridrato de metformina é um agente antidiabético que melhora a tolerância à glicose em pacientes com diabetes tipo 2 e reduz os níveis plasmáticos basais de glicose. Neste estudo, um projeto experimental do tipo "centróide simplex" com 69 tomadas foi usado para selecionar a melhor combinação de alguns polímeros hidrofílicos que gerou um perfil de liberação da metformina.HCl de 24 horas. O modelo Korsmeyer-Peppas foi usado para modelar os perfis de dissolução, uma vez que apresentou os melhores ajustes aos dados experimentais. Além disso, um modelo cúbico previu a melhor formulação de metformina.HCl sendo aquela contendo polivinilpirrolidona, etilcelulose, hidroxipropilmetil celulose, carragena, alginato de sódio e goma arábica nos níveis 6.26, 68.7, 6.26, 6.26, 6.26 e 6.26 %, respectivamente. As corridas de validação confirmaram a precisão do modelo cúbico com os seis componentes para prever o melhor conjunto de componentes que originou uma

  10. Hollow porous ionic liquids composite polymers based solid phase extraction coupled online with high performance liquid chromatography for selective analysis of hydrophilic hydroxybenzoic acids from complex samples.

    Science.gov (United States)

    Dai, Xingping; Wang, Dongsheng; Li, Hui; Chen, Yanyi; Gong, Zhicheng; Xiang, Haiyan; Shi, Shuyun; Chen, Xiaoqing

    2017-02-10

    Polar and hydrophilic properties of hydroxybenzoic acids usually made them coelute with interferences in high performance liquid chromatography (HPLC) analysis. Then selective analysis of them was necessary. Herein, hollow porous ionic liquids composite polymers (PILs) based solid phase extraction (SPE) was firstly fabricated and coupled online with HPLC for selective analysis of hydroxybenzoic acids from complex matrices. Hollow porous PILs were firstly synthesized using Mobil Composition of Matter No. 48 (MCM-48) spheres as sacrificial support, 1-vinyl-3-methylimidazolium chloride (VMIM(+)Cl(-)) as monomer, and ethylene glycol dimethacrylate (EGDMA) as cross-linker. Various parameters affecting synthesis, adsorption and desorption behaviors were investigated and optimized. Steady-state adsorption studies showed the resulting hollow porous PILs exhibited high adsorption capacity, fast adsorption kinetics, and excellent specific adsorption. Subsequently, the application of online SPE system was studied by selective analysis of protocatechuic acid (PCA), 4-hydroxybenzoic acid (4-HBA), and vanillic acid (VA) from Pollen Typha angustifolia. The obtained limit of detection (LOD) varied from 0.002 to 0.01μg/mL, the linear range (0.05-5.0μg/mL) was wide with correlation coefficient (R) from 0.9982 to 0.9994, and the average recoveries at three spiking levels ranged from 82.7 to 102.4%, with column-to-column relative standard deviation (RSD) below 8.1%. The proposed online method showed good accuracy, precision, specificity and convenience, which opened up a universal and efficient route for selective analysis of hydroxybenzoic acids from complex samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Soluble and insoluble fiber (image)

    Science.gov (United States)

    ... stool. There are two types of dietary fiber, soluble and insoluble. Soluble fiber retains water and turns to gel during ... and nutrient absorption from the stomach and intestine. Soluble fiber is found in foods such as oat ...

  12. Poly(ethylene glycol)-grafted cyclic acetals based polymer networks with non-water-swellable, biodegradable and surface hydrophilic properties

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Ruixue, E-mail: qdruinyan@hotmail.com [Complex and Intelligent Research Center, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai (China); Zhang, Nan; Wu, Wentao [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Wang, Kemin, E-mail: kemin-wang@hotmail.com [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China)

    2016-05-01

    Cyclic acetals based biomaterial without acidic products during hydrolytic degradation is a promising candidate for tissue engineering applications; however, low hydrophilicity is still one limitation for its biomedical application. In this work, we aim to achieve non-water-swellable cyclic acetal networks with improved hydrophilicity and surface wettability by copolymerization of cyclic acetal units based monomer, 5-ethyl-5-(hydroxymethyl)-β,β-dimethyl-1, 3-dioxane-2-ethanol diacrylate (EHD) and methoxy poly(ethylene glycol) monoacrylate (mPEGA) under UV irradiation, to avoid swelling of conventional hydrogels which could limit their applicability in particular of the mechanical properties and geometry integrity. Various EHD/mPEGA networks were fabricated with different concentrations of mPEGA from 0 to 30%, and the results showed photopolymerization behavior, mechanical property and thermal stability could not be significantly affected by addition of mPEGA, while the surface hydrophilicity was dramatically improved with the increase of mPEGA and could achieve a water contact angle of 37° with 30% mPEGA concentration. The obtained EHD/mPEGA network had comparative degradation rate to the PECA hydrogels reported previously, and MTT assay indicated it was biocompatible to L929 cells. - Highlights: • Cyclic acetals contained EHD/mPEGA networks were fabricated by photopolymerization. • It can be degraded under simulated physiological condition without acidic products. • Surface hydrophilicity was increased without swelling in water.

  13. Poly(ethylene glycol)-grafted cyclic acetals based polymer networks with non-water-swellable, biodegradable and surface hydrophilic properties.

    Science.gov (United States)

    Yin, Ruixue; Zhang, Nan; Wu, Wentao; Wang, Kemin

    2016-05-01

    Cyclic acetals based biomaterial without acidic products during hydrolytic degradation is a promising candidate for tissue engineering applications; however, low hydrophilicity is still one limitation for its biomedical application. In this work, we aim to achieve non-water-swellable cyclic acetal networks with improved hydrophilicity and surface wettability by copolymerization of cyclic acetal units based monomer, 5-ethyl-5-(hydroxymethyl)-β,β-dimethyl-1, 3-dioxane-2-ethanol diacrylate (EHD) and methoxy poly(ethylene glycol) monoacrylate (mPEGA) under UV irradiation, to avoid swelling of conventional hydrogels which could limit their applicability in particular of the mechanical properties and geometry integrity. Various EHD/mPEGA networks were fabricated with different concentrations of mPEGA from 0 to 30%, and the results showed photopolymerization behavior, mechanical property and thermal stability could not be significantly affected by addition of mPEGA, while the surface hydrophilicity was dramatically improved with the increase of mPEGA and could achieve a water contact angle of 37° with 30% mPEGA concentration. The obtained EHD/mPEGA network had comparative degradation rate to the PECA hydrogels reported previously, and MTT assay indicated it was biocompatible to L929 cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Boronate affinity monolith with a gold nanoparticle-modified hydrophilic polymer as a matrix for the highly specific capture of glycoproteins.

    Science.gov (United States)

    Wu, Ci; Liang, Yu; Zhao, Qun; Qu, Yanyan; Zhang, Shen; Wu, Qi; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2014-07-07

    As low abundance is the great obstacle for glycoprotein analysis, the development of materials with high efficiency and selectivity for glycoprotein enrichment is a prerequisite in glycoproteome research. Herein, we report a new kind of hydrophilic boronate affinity monolith by attaching 4-mercaptophenylboronic acid (MPBA) with 2-mercaptoethylamine (MPA) on the gold nanoparticle-modified poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate)) monolith for glycoprotein enrichment. With poly(ethylene glycol) diacrylate as the cross-linker and the further modification of gold nanoparticles, the matrix has advantages of good hydrophilicity and enhanced surface area, which are beneficial to improve the enrichment selectivity and efficiency for glycoproteins. The attachment of MPBA and MPA provide intramolecular BN coordination, which could further enhance the specificity of glycoprotein capture. Such a boronate affinity monolith was applied to enrich horseradish peroxidase (HRP) from the mixture of HRP and bovine serum albumin (BSA), and high selectivity was obtained even at a mass ratio of 1:1000. In addition, the binding capacity of ovalbumin on such monolith reached 390 μg g(-1) . Furthermore, the average recovery of HRP on the prepared affinity monoliths was (84.8±1.9) %, obtained in three times enrichment with the same column. Finally, the boronate affinity monolith was successfully applied for the human-plasma glycoproteome analysis. As a result, 160 glycoproteins were credibly identified from 9 μg of human plasma, demonstrating the great potential of such a monolith for large-scale glycoproteome research. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Water-insoluble Silk Films with Silk I Structure

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Q.; Hu, X; Wang, X; Kluge, J; Lu, S; Cebe, P; Kaplan, D

    2010-01-01

    Water-insoluble regenerated silk materials are normally produced by increasing the {beta}-sheet content (silk II). In the present study water-insoluble silk films were prepared by controlling the very slow drying of Bombyx mori silk solutions, resulting in the formation of stable films with a predominant silk I instead of silk II structure. Wide angle X-ray scattering indicated that the silk films stabilized by slow drying were mainly composed of silk I rather than silk II, while water- and methanol-annealed silk films had a higher silk II content. The silk films prepared by slow drying had a globule-like structure at the core surrounded by nano-filaments. The core region was composed of silk I and silk II, surrounded by hydrophilic nano-filaments containing random turns and {alpha}-helix secondary structures. The insoluble silk films prepared by slow drying had unique thermal, mechanical and degradative properties. Differential scanning calorimetry results revealed that silk I crystals had stable thermal properties up to 250 C, without crystallization above the T{sub g}, but degraded at lower temperatures than silk II structure. Compared with water- and methanol-annealed films the films prepared by slow drying had better mechanical ductility and were more rapidly enzymatically degraded, reflecting the differences in secondary structure achieved via differences in post processing of the cast silk films. Importantly, the silk I structure, a key intermediate secondary structure for the formation of mechanically robust natural silk fibers, was successfully generated by the present approach of very slow drying, mimicking the natural process. The results also point to a new mode of generating new types of silk biomaterials with enhanced mechanical properties and increased degradation rates, while maintaining water insolubility, along with a low {beta}-sheet content.

  16. Double emulsions for the compatibilization of hydrophilic nanocellulose with non-polar polymers and validation in the synthesis of composite fibers.

    Science.gov (United States)

    Carrillo, Carlos A; Nypelö, Tiina; Rojas, Orlando J

    2016-03-14

    A route for the compatibilization of aqueous dispersions of cellulose nanofibrils (CNFs) with a non-polar polymer matrix is proposed to overcome a major challenge in CNF-based material synthesis. Non-ionic surfactants were used in CNF aqueous dispersions equilibrated with an organic phase (for demonstration, a polystyrene solution, PS, was used). Stable water-in-oil-in-water (W/O/W) double emulsions were produced as a result of the compromise between composition and formulation variables. Most remarkably, the proposed route for CNF integration with hydrophobic polymers removed the need for drying or solvent-exchange of the CNF aqueous dispersion prior to processing. The rheological behavior of the double emulsions showed strong shear thinning behavior and facilitated CNF-PS co-mixing in solid nanofibers upon electrospinning. The morphology and thermal properties of the resultant nanofibers revealed that CNFs were efficiently integrated in the hydrophobic matrix which was consistent with the high interfacial area of the precursor double emulsion. In addition, the morphology and quality of the composite nanofibers can be controlled by the conductivity (ionic strength) of the CNF dispersion. Overall, double emulsion systems are proposed as a novel, efficient and scalable platform for CNF co-processing with non-polar systems and they open up the possibility for the redispersion of CNFs after removal of the organic phase.

  17. Hydrophilic Carotenoids: Recent Progress

    Directory of Open Access Journals (Sweden)

    Attila Agócs

    2012-04-01

    Full Text Available Carotenoids are substantially hydrophobic antioxidants. Hydrophobicity is this context is rather a disadvantage, because their utilization in medicine as antioxidants or in food chemistry as colorants would require some water dispersibility for their effective uptake or use in many other ways. In the past 15 years several attempts were made to synthetize partially hydrophilic carotenoids. This review compiles the recently synthetized hydrophilic carotenoid derivatives.

  18. Improving drug loading of mucosal solvent cast films using a combination of hydrophilic polymers with amoxicillin and paracetamol as model drugs.

    Science.gov (United States)

    Boateng, Joshua; Mani, Justine; Kianfar, Farnoosh

    2013-01-01

    Solvent cast mucosal films with improved drug loading have been developed by combining carboxymethyl cellulose (CMC), sodium alginate (SA), and carrageenan (CAR) using paracetamol and amoxicillin as model drugs and glycerol (GLY) as plasticizer. Films were characterized using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), folding resilience, swelling capacity, mucoadhesivity, and drug dissolution studies. SA, CMC, and GLY (5 : 3 : 6) films showed maximum amoxicillin loading of 26.3% whilst CAR, CMC, and GLY (1 : 2 : 3) films had a maximum paracetamol loading of 40%. XRPD analysis showed different physical forms of the drugs depending on the amount loaded. Films containing 29.4% paracetamol and 26.3% amoxicillin showed molecular dispersion of the drugs while excess paracetamol was observed on the film surface when the maximum 40% was loaded. Work of adhesion was similar for blank films with slightly higher cohesiveness for CAR and CMC based films, but the differences were significant between paracetamol and amoxicillin containing films. The stickiness and cohesiveness for drug loaded films were generally similar with no significant differences. The maximum percentage cumulative drug release was 84.65% and 70.59% for paracetamol and amoxicillin, respectively, with anomalous case two transport mechanism involving both drug diffusion and polymer erosion.

  19. Improving Drug Loading of Mucosal Solvent Cast Films Using a Combination of Hydrophilic Polymers with Amoxicillin and Paracetamol as Model Drugs

    Directory of Open Access Journals (Sweden)

    Joshua Boateng

    2013-01-01

    Full Text Available Solvent cast mucosal films with improved drug loading have been developed by combining carboxymethyl cellulose (CMC, sodium alginate (SA, and carrageenan (CAR using paracetamol and amoxicillin as model drugs and glycerol (GLY as plasticizer. Films were characterized using X-ray powder diffraction (XRPD, scanning electron microscopy (SEM, folding resilience, swelling capacity, mucoadhesivity, and drug dissolution studies. SA, CMC, and GLY (5 : 3 : 6 films showed maximum amoxicillin loading of 26.3% whilst CAR, CMC, and GLY (1 : 2 : 3 films had a maximum paracetamol loading of 40%. XRPD analysis showed different physical forms of the drugs depending on the amount loaded. Films containing 29.4% paracetamol and 26.3% amoxicillin showed molecular dispersion of the drugs while excess paracetamol was observed on the film surface when the maximum 40% was loaded. Work of adhesion was similar for blank films with slightly higher cohesiveness for CAR and CMC based films, but the differences were significant between paracetamol and amoxicillin containing films. The stickiness and cohesiveness for drug loaded films were generally similar with no significant differences. The maximum percentage cumulative drug release was 84.65% and 70.59% for paracetamol and amoxicillin, respectively, with anomalous case two transport mechanism involving both drug diffusion and polymer erosion.

  20. Modification and Applications of Hydrophilic Polypropylene Membrane

    Science.gov (United States)

    Ariono, Danu; Kusuma Wardani, Anita

    2017-07-01

    Polypropylene (PP) is one of the most important polymers for microporous membrane due to its high void volume, well-controlled porosity, high thermal and chemical stability, and low cost. However, the hydrophobicity of PP becomes a limitation to broaden its applications. Furthermore, membrane fouling occurs more seriously on hydrophobic membranes than hydrophilic ones. To solve this problem, surface modifications have been developed to enhance PP membrane hydrophilicity without changing its bulk properties. Graft polymerization and plasma treatment are the most popular techniques for surface hydrophilization. Some studies showed that highly hydrophilic PP membranes with water contact angle less than 20° could be obtained by plasma treatment and graft polymerization. Furthermore, during plasma treatment, polar groups were formed on the PP membrane surface thus increased water uptake. To bring brief explanation on various research trends for PP modification, this paper provides a review of surface hydrophilization of microporous PP membrane, including plasma treatment and graft polymerization. The effects of surface modification on PP membrane performance such as porosity, water contact angle, and water flux are also discussed. In addition, the applications of modified PP membrane are presented as well.

  1. Parameterization of cloud droplet formation for global and regional models: including adsorption activation from insoluble CCN

    Directory of Open Access Journals (Sweden)

    P. Kumar

    2009-04-01

    Full Text Available Dust and black carbon aerosol have long been known to exert potentially important and diverse impacts on cloud droplet formation. Most studies to date focus on the soluble fraction of these particles, and overlook interactions of the insoluble fraction with water vapor (even if known to be hydrophilic. To address this gap, we developed a new parameterization that considers cloud droplet formation within an ascending air parcel containing insoluble (but wettable particles externally mixed with aerosol containing an appreciable soluble fraction. Activation of particles with a soluble fraction is described through well-established Köhler theory, while the activation of hydrophilic insoluble particles is treated by "adsorption-activation" theory. In the latter, water vapor is adsorbed onto insoluble particles, the activity of which is described by a multilayer Frenkel-Halsey-Hill (FHH adsorption isotherm modified to account for particle curvature. We further develop FHH activation theory to i find combinations of the adsorption parameters AFHH, BFHH which yield atmospherically-relevant behavior, and, ii express activation properties (critical supersaturation that follow a simple power law with respect to dry particle diameter.

    The new parameterization is tested by comparing the parameterized cloud droplet number concentration against predictions with a detailed numerical cloud model, considering a wide range of particle populations, cloud updraft conditions, water vapor condensation coefficient and FHH adsorption isotherm characteristics. The agreement between parameterization and parcel model is excellent, with an average error of 10% and R2~0.98. A preliminary sensitivity study suggests that the sublinear response of droplet number to Köhler particle concentration is not as strong for FHH particles.

  2. Oral floating extended release stavudine hydrophilic matrix tablets ...

    African Journals Online (AJOL)

    Formulation of extended-release (ER) d4T improves patient compliance and minimizes dose related side effects. This study, therefore, aims at formulating once-a-day floating d4T ER hydrophilic matrix tablets using hydroxypropyl methylcellulose (HPMC) as a release-modifying polymer. NaHCO3 and microcrystalline ...

  3. Polymeric Nanosuspensions for Enhanced Dissolution of Water Insoluble Drugs

    Directory of Open Access Journals (Sweden)

    Roya Yadollahi

    2013-01-01

    Full Text Available The aim of the present research is to formulate and evaluate polymeric nanosuspensions containing three model water insoluble drugs, nifedipine (NIF, carbamazepine (CBZ, and ibuprofen (IBU with various physicochemical properties. The nanosuspensions were prepared from hydroxypropyl methylcellulose (HPMC and polyvinylpyrrolidone (PVP by a cosolvent technique with polyethylene glycol (PEG-300 and water as the cosolvents. Physicochemical and morphological characteristics of the nanosuspensions (particle size, polydispersity index, and crystallinity have been correlated with the drug release behaviour. The effects of polymer, drug ratio on the physical, morphological, and dissolution characteristics of the drugs are reported. Drug release is significantly enhanced from the nanosuspensions; for example, the maximum NIF, IBU, and CBZ concentrations after 8-hour dissolution are increased approximately 37, 2, and 1.2 times, respectively, in comparison with the pure powdered drugs. Based on this solubilization enhancement performance, the nanosuspensions have potential for increasing the orally dosed bioavailability of NIF, IBU, and CBZ.

  4. Alzheimer's disease: insolubility of partially purified paired helical filaments in sodium dodecyl sulfate and urea.

    Science.gov (United States)

    Selkoe, D J; Ihara, Y; Salazar, F J

    1982-03-05

    A method is described for the partial purification of the paired helical filaments that accumulate progressively in human neurons in Alzheimer's disease (senile dementia). Paired helical filaments have unusual solubility characteristics, including insolubility in sodium dodecyl sulfate, urea, reducing agent, and guanidine, which prevent analysis of their molecular composition by gel electrophoresis. The paired helical filaments appear to contain covalent bonds other than disulfide, which cross-link individual filaments into a rigid intracellular polymer. Thus, paired helical filaments appear to represent an example in neurons of an insoluble cross-linked protein. Covalently cross-linked protein polymers occur in lens senile cataracts and in terminally differentiated skin keratinocytes, suggesting that there may be a common mechanism for remodeling some structural proteins during cell aging.

  5. Insoluble-Bound Phenolics in Food.

    Science.gov (United States)

    Shahidi, Fereidoon; Yeo, Ju-Dong

    2016-09-11

    This contribution provides a review of the topic of insoluble-bound phenolics, especially their localization, synthesis, transfer and formation in plant cells, as well as their metabolism in the human digestive system and corresponding bioactivities. In addition, their release from the food matrix during food processing and extraction methods are discussed. The synthesis of phenolics takes place mainly at the endoplasmic reticulum and they are then transferred to each organ through transport proteins such as the ATP-binding cassette (ABC) and multidrug and toxic compound extrusion (MATE) transporter at the organ's compartment membrane or via transport vesicles such as cytoplasmic and Golgi vesicles, leading to the formation of soluble and insoluble-bound phenolics at the vacuole and cell wall matrix, respectively. This part has not been adequately discussed in the food science literature, especially regarding the synthesis site and their transfer at the cellular level, thus this contribution provides valuable information to the involved scientists. The bound phenolics cannot be absorbed at the small intestine as the soluble phenolics do (5%-10%), thus passing into the large intestine and undergoing fermentation by a number of microorganisms, partially released from cell wall matrix of foods. Bound phenolics such as phenolic acids and flavonoids display strong bioactivities such as anticancer, anti-inflammation and cardiovascular disease ameliorating effects. They can be extracted by several methods such as acid, alkali and enzymatic hydrolysis to quantify their contents in foods. In addition, they can also be released from the cell wall matrix during food processing procedures such as fermentation, germination, roasting, extrusion cooking and boiling. This review provides critical information for better understanding the insoluble-bound phenolics in food and fills an existing gap in the literature.

  6. Challenges in measuring insoluble dietary fiber.

    Science.gov (United States)

    Mertens, D R

    2003-12-01

    Objectives of this review are to define criteria for evaluating insoluble dietary fiber (IDF) methods, discuss their relevance in meeting the nutritional needs of ruminants and herbivores, describe problems with empirical IDF methods, and assess their relative merits. The challenge for the researcher, nutritionist, and analyst is to select fiber methods that are relevant and reproducible. Without relevance, there is no reason to measure IDF, and without reproducibility, there is no value in doing so. Insoluble dietary fiber is a complex matrix of chemical components, and there are no primary standards that can be used to establish the validity of methods. Thus, the definition of fiber is crucial in determining method relevance. For ruminants and nonruminant herbivores, the appropriate physiological definition for selecting IDF methods may be as follows: the organic fraction of the diet that is indigestible or slowly digesting and occupies space in the gastrointestinal tract. Crude fiber does not match this definition, and its use should be abandoned. Acid detergent fiber does not measure all IDF but is useful when included with other dietary fiber methods to describe some feeds. Several current methods, including amylase-treated neutral detergent fiber (aNDF) and enzymatic-gravimetric methods, are relevant for measuring IDF. In a collaborative study, aNDF obtained a standard deviation of reproducibility (SD(R)) of 1.3%. Enzymatic-gravimetric methods of measuring IDF have been evaluated using too few feed materials to make statistically valid conclusions, but the SD(R)f IDF, for the few feeds evaluated, were similar to aNDF (0.9 to 2.4%). The enzymatic-chemical method of measuring IDF as the sum of insoluble nonstarch polysaccharides and lignin agrees with NDF, but the SDR of neutral sugar analysis using acid hydrolysis and chromatography is greater (3.2%) than other dietary fiber methods. Empirical methods--such as those used to measure IDF, although based on

  7. Neutral hydrophilic cathode catalyst binders for microbial fuel cells

    KAUST Repository

    Saito, Tomonori

    2011-01-01

    Improving oxygen reduction in microbial fuel cell (MFC) cathodes requires a better understanding of the effects of the catalyst binder chemistry and properties on performance. A series of polystyrene-b-poly(ethylene oxide) (PS-b-PEO) polymers with systematically varying hydrophilicity were designed to determine the effect of the hydrophilic character of the binder on cathode performance. Increasing the hydrophilicity of the PS-b-PEO binders enhanced the electrochemical response of the cathode and MFC power density by ∼15%, compared to the hydrophobic PS-OH binder. Increased cathode performance was likely a result of greater water uptake by the hydrophilic binder, which would increase the accessible surface area for oxygen reduction. Based on these results and due to the high cost of PS-b-PEO, the performance of an inexpensive hydrophilic neutral polymer, poly(bisphenol A-co-epichlorohydrin) (BAEH), was examined in MFCs and compared to a hydrophilic sulfonated binder (Nafion). MFCs with BAEH-based cathodes with two different Pt loadings initially (after 2 cycles) had lower MFC performance (1360 and 630 mW m-2 for 0.5 and 0.05 mg Pt cm-2) than Nafion cathodes (1980 and 1080 mW m -2 for 0.5 and 0.05 mg Pt cm-2). However, after long-term operation (22 cycles, 40 days), power production of each cell was similar (∼1200 and 700-800 mW m-2 for 0.5 and 0.05 mg Pt cm-2) likely due to cathode biofouling that could not be completely reversed through physical cleaning. While binder chemistry could improve initial electrochemical cathode performance, binder materials had less impact on overall long-term MFC performance. This observation suggests that long-term operation of MFCs will require better methods to avoid cathode biofouling. © 2011 The Royal Society of Chemistry.

  8. Diffusion of insoluble carbon in zirconium oxides

    CERN Document Server

    Vykhodets, V B; Koester, U; Kondrat'ev, V V; Kesarev, A G; Hulsen, C; Kurennykh, T E

    2011-01-01

    The diffusion coefficient of insoluble carbon in zirconium oxides has been obtained for the temperature range of 900-1000A degrees C. There are no published data on the diffusion of insoluble impurities; these data are of current interest for the diffusion theory and nuclear technologies. Tracer atoms 13C have been introduced into oxides by means of ion implantation and the kinetics of their emission from the samples in the process of annealing in air has been analyzed. The measurements have been performed using the methods of nuclear microanalysis and X-ray photoelectron spectroscopy. The diffusion activation energy is 2.7 eV and the carbon diffusion coefficient is about six orders of magnitude smaller than that for oxygen self-diffusion in the same systems. This result indicates the strong anomaly of the diffusion properties of carbon in oxides. As a result, zirconium oxides cannot be used in some nuclear technologies, in particular, as a material of sources for accelerators of short-lived carbon isotopes.

  9. Photo-grafting polymerization, microstructure and hydrophilicity of spun-blown polypropylene nonwoven fabrics

    Science.gov (United States)

    Zhu, X.; Shi, X.; Pan, Z.; Fang, Y.; Wu, Y.

    2017-10-01

    The non-polarity and poor hygroscopicity of polypropylene (PP) impede its wide application. The polar monomers, glycidyl methacrylate (GMA), hydroxyethyl methacrylate (HEMA) and methacrylamido propyl trimethyl ammonium chloride (MAPTAC) were grafted onto the spun-blown polypropylene nonwoven fabric (SMS) under ultraviolet irradiation, and the subsequent functionalization of the grafted fabrics was implemented as well. The results show that both the monomer and the polymer of HEMA are hydrophilic and are grafted uniformly onto the fabric surface as well as into the melt-blown layer with the hydrophilicity being enhanced slightly, whereas the hydrophilic monomer yet the hydrophobic polymer of MAPTAC prefer to be grafted onto the melt-blown fibre with the wicking effect. Both the monomer and the polymer of GMA are hydrophobic and are favourably grafted into the meltblown layer with no hydrophilicity being improved. The grafting diminishes the fibre crystallinity and melting temperature, especially significant for the graftings of hydrophobic polymers, PGMA and PMAPTAC. All the grafting reduces the water flux of the grafted fabrics no matter what the grafting polymers are hydrophilicity or hydrophobicity not.

  10. Variation in emulsion stabilization behavior of hybrid silicone polymers with change in molecular structure: Phase diagram study.

    Science.gov (United States)

    Mehta, Somil C; Somasundaran, P; Kulkarni, Ravi

    2009-05-15

    Silicone oils are widely used in cosmetics and personal care applications to improve softness and condition skin and hair. Being insoluble in water and most hydrocarbons, a common mode of delivering them is in the form of emulsions. Currently most applications use polyoxyethylene (non-ionic) modified siloxanes as emulsifiers to stabilize silicone oil emulsions. However, ionically grafted silicone polymers have not received much attention. Ionic silicones have significantly different properties than the non-ionic counterpart. Thus considerable potential exists to formulate emulsions of silicones with different water/silicone oil ratios for novel applications. In order to understand the mechanisms underlying the effects of hydrophilic modifications on the ability of hybrid silicone polymers to stabilize various emulsions, this article focuses on the phase diagram studies for silicone emulsions. The emulsifying ability of functional silicones was seen to depend on a number of factors including hydrophilicity of the polymer, nature of the functional groups, the extent of modification, and the method of emulsification. It was observed that the region of stable emulsion in a phase diagram expanded with increase in shear rate. At a given shear rate, the region of stable emulsion and the nature of emulsion (water-in-oil or oil-in-water) was observed to depend on hydrophilic-hydrophobic balance of the hybrid silicone emulsifier. At a fixed amount of modification, the non-ionically modified silicone stabilized an oil-in-water emulsion, whereas the ionic silicones stabilized inverse water-in-oil emulsions. This was attributed to the greater hydrophilicity of the polyoxyethylene modified silicones than the ionic counterparts. In general, it is postulated that with progressive increase in hydrophilicity of hybrid silicone emulsifiers, their tendency to stabilize water-in-oil emulsion decreases with corresponding increase in oil-in-water emulsion. Further, this behavior is

  11. Hydrophilic-Core Microcapsules and Their Formation

    Science.gov (United States)

    Calle, Luz M. (Inventor); Li, Wenyan (Inventor); Buhrow, Jerry W. (Inventor); Jolley, Scott T. (Inventor)

    2016-01-01

    Hydrophilic-core microcapsules and methods of their formation are provided. A hydrophilic-core microcapsule may include a shell that encapsulates water with the core substance dissolved or dispersed therein. The hydrophilic-core microcapsules may be formed from an emulsion having hydrophilic-phase droplets dispersed in a hydrophobic phase, with shell-forming compound contained in the hydrophilic phase or the hydrophobic phase and the core substance contained in the hydrophilic phase. The shells of the microcapsules may be capable of being broken down in response to being contacted by an alkali, e.g., produced during corrosion, contacting the shell.

  12. Method of making a membrane having hydrophilic and hydrophobic surfaces for adhering cells or antibodies by using atomic oxygen or hydroxyl radicals

    Science.gov (United States)

    Koontz, Steven L. (Inventor); Spaulding, Glenn F. (Inventor)

    1994-01-01

    A portion of an organic polymer article such as a membrane is made hydrophilic by exposing a hydrophobic surface of the article to a depth of about 50 to about 5000 angstroms to atomic oxygen or hydroxyl radicals at a temperature below 100C., preferably below 40 C, to form a hydrophilic uniform surface layer of hydrophilic hydroxyl groups. The atomic oxygen and hydroxyl radicals are generated by a flowing afterglow microwave discharge, and the surface is outside of a plasma produced by the discharge. A membrane having both hydrophilic and hydrophobic surfaces can be used in an immunoassay by adhering antibodies to the hydrophobic surface. In another embodiment, the membrane is used in cell culturing where cells adhere to the hydrophilic surface. Prior to adhering cells, the hydrophilic surface may be grafted with a compatibilizing compound. A plurality of hydrophilic regions bounded by adjacent hydrophobic regions can be produced such that a maximum of one cell per each hydrophilic region adheres.

  13. 21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Insoluble glucose isomerase enzyme preparations... enzyme preparations. (a) Insoluble glucose isomerase enzyme preparations are used in the production of... additional requirements for enzyme preparations in the Food Chemicals Codex, 3d Ed. (1981), p. 107, which is...

  14. Process for recovering deashing solvent from insoluble coal products

    Energy Technology Data Exchange (ETDEWEB)

    Rado, T.A.

    1982-02-02

    A process for effecting deashing solvent recovery from insoluble coal products and preparing a slurry of the insoluble products. An elevated temperature and pressure stream comprising insoluble coal products and deashing solvent is admixed with a makeup liquid to dilute the stream. The diluted stream is reduced in pressure and introduced into a first treatment vessel containing sufficient slurry to provide a hydrostatic pressure to prevent boiling of the diluted stream upon entry therein. The solvent then is permitted to flash and cool the remainder of the slurry. A portion of the cooled slurry is recycled to provide the makeup liquid and a second portion is introduced into a second treatment vessel to permit diffusion of solvent infused into the insoluble coal products in the slurry. The slurry of insoluble coal products in the second vessel then is introduced into a thickener to concentrate the slurry and provide a feed suitable for a gasifier.

  15. Hydrophilic structures for condensation management in appliances

    Science.gov (United States)

    Kuehl, Steven John; Vonderhaar, John J.; Wu, Guolian; Wu, Mianxue

    2016-02-02

    An appliance that includes a cabinet having an exterior surface; a refrigeration compartment located within the cabinet; and a hydrophilic structure disposed on the exterior surface. The hydrophilic structure is configured to spread condensation. The appliance further includes a wicking structure located in proximity to the hydrophilic structure, and the wicking structure is configured to receive the condensation.

  16. Exploring the effect of hydrophilic and hydrophobic structure of grafted polymeric micelles on drug loading.

    Science.gov (United States)

    Shi, Chenjun; Sun, Yujiao; Wu, Haiyang; Zhu, Chengyun; Wei, Guoguang; Li, Jinfeng; Chan, Tenglan; Ouyang, Defang; Mao, Shirui

    2016-10-15

    The objective of this paper is to explore the effect of hydrophilic and hydrophobic structure of grafted polymeric micelles on drug loading, and elucidate whether drug-polymer compatibility, as predicted by Hansen solubility parameters (HSPs), can be used as a tool for drug-polymer pairs screening and guide the design of grafted polymeric micelles. HSPs of 27 drugs and three grafted copolymers were calculated according to group contribution method. The drug-polymer compatibilities were evaluated using the approaches of Flory-Huggins interaction parameters (χFH) and polarity difference (△Xp). Two models, model A and B, were put forward for drug-polymer compatibility prediction. In model A, hydrophilic/hydrophobic part as a whole was regarded as one segment. And, in model B, hydrophilic and hydrophobic segments were evaluated individually. First of all, using chitosan (CS)-grafted-glyceryl monooeate (GMO) based micelle as an example, the suitability of model A and model B for predicating drug-polymer compatibility was evaluated theoretically. Thereafter, corresponding experiments were carried out to check the validity of the theoretical prediction. It was demonstrated that Model B, which evaluates drug compatibility with both hydrophilic and hydrophobic segments of the copolymer, is more reliable for drug-polymer compatibility prediction. Moreover, the approach of model B allows for the selection of a defined grafted polymer with for a specific drug and vice versa. Thus, drug compatibility evaluation via HSPs with both hydrophilic and hydrophobic segments is a suitable tool for the rational design of grafted polymeric micelles. The molecular dynamics (MD) simulation study provided further support to the established model and experimental results. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Surface hydrophilicity of PLGA fibers governs in vitro mineralization and osteogenic differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Minnah; Arora, Aditya; Katti, Dhirendra S., E-mail: dsk@iitk.ac.in

    2014-12-01

    Interfacial properties of biomaterials play an important role in governing their interaction with biological microenvironments. This work investigates the role of surface hydrophilicity of electrospun poly(lactide-co-glycolide) (PLGA) fibers in determining their biological response. For this, PLGA is blended with varying amounts of Pluronic®F-108 and electrospun to fabricate microfibers with varying surface hydrophilicity. The results of mineralization study in simulated body fluid (SBF) demonstrate a significant enhancement in mineralization with an increase in surface hydrophilicity. While presence of serum proteins in SBF reduces absolute mineral content, mineralization continues to be higher on samples with higher surface hydrophilicity. The results from in vitro cell culture studies demonstrate a marked improvement in mesenchymal stem cell —adhesion, elongation, proliferation, infiltration, osteogenic differentiation and matrix mineralization on hydrophilized fibers. Therefore, hydrophilized PLGA fibers are advantageous both in terms of mineralization and elicitation of favorable cell response. Since most of the polymeric materials being used in orthopedics are hydrophobic in nature, the results from this study have strong implications in the future design of interfaces of such hydrophobic materials. In addition, the work proposes a facile method for the modification of electrospun fibers of hydrophobic polymers by blending with a poloxamer for improved bone tissue regeneration. - Highlights: • Surface hydrophilicity of PLGA modulated by blending with Pluronic F-108. • Hydrophilized fibers support better in vitro mineralization. • Mineralization trends retained in the presence of adsorbed serum proteins. • Hydrophilized fibers promote better cell adhesion and proliferation. • Hydrophilized fibers also enable better osteogenic differentiation.

  18. Preparation and Characterization of Hydrophilically Modified PVDF Membranes by a Novel Nonsolvent Thermally Induced Phase Separation Method

    Science.gov (United States)

    Hu, Ningen; Xiao, Tonghu; Cai, Xinhai; Ding, Lining; Fu, Yuhua; Yang, Xing

    2016-01-01

    In this study, a nonsolvent thermally-induced phase separation (NTIPS) method was first proposed to fabricate hydrophilically-modified poly(vinylidene fluoride) (PVDF) membranes to overcome the drawbacks of conventional thermally-induced phase separation (TIPS) and nonsolvent-induced phase separation (NIPS) methods. Hydrophilically-modified PVDF membranes were successfully prepared by blending in hydrophilic polymer polyvinyl alcohol (PVA) at 140 °C. A series of PVDF/PVA blend membranes was prepared at different total polymer concentrations and blend ratios. The morphological analysis via SEM indicated that the formation mechanism of these hydrophilically-modified membranes was a combined NIPS and TIPS process. As the total polymer concentration increased, the tensile strength of the membranes increased; meanwhile, the membrane pore size, porosity and water flux decreased. With the PVDF/PVA blend ratio increased from 10:0 to 8:2, the membrane pore size and water flux increased. The dynamic water contact angle of these membranes showed that the hydrophilic properties of PVDF/PVA blend membranes were prominently improved. The higher hydrophilicity of the membranes resulted in reduced membrane resistance and, hence, higher permeability. The total resistance Rt of the modified PVDF membranes decreased significantly as the hydrophilicity increased. The irreversible fouling related to pore blocking and adsorption fouling onto the membrane surface was minimal, indicating good antifouling properties. PMID:27869711

  19. Nanostructure of polymer monolayer and polyelectrolyte brush at air/water interface by X-ray and neutron reflectometry

    CERN Document Server

    Matsuoka, H; Matsumoto, K

    2003-01-01

    The nanostructure of amphiphilic diblock copolymer monolayer on water was directly investigated by in situ X-ray and neutron reflectivity techniques. The diblock copolymer consists of polysilacyclobutane, which is very flexible, as a hydrophobic block and polymethacrylic acid, an anionic polymer, as a hydrophilic block. The polymers with shorter hydrophilic segment formed a very smooth and uniform monolayer with hydrophobic layer on water and dense hydrophilic layer under the water. But the longer hydrophilic segment polymer formed three-layered monolayer with polyelectrolyte brush in addition to hydrophobic and dense hydrophilic layers. The dense hydrophilic layer is thought to be formed to avoid a contact between hydrophobic polymer layer and water. Its role is something like a 'carpet'. An additional interesting information is that the thickness of the 'carpet layer' is almost 15A, independent the surface pressure and hydrophilic polymer length. Highly quantitative information was obtained about the nanost...

  20. High Molecular Weight Polymers in the New Chemicals Program

    Science.gov (United States)

    There are three categories or types of High Molecular Weight (HMW, 10,000 daltons) polymers typically reviewed by the New Chemicals Program: Soluble, insoluble, and water absorbing. Each of the three types are treated differently.

  1. Encapsulation systems for the delivery of hydrophilic nutraceuticals: Food application.

    Science.gov (United States)

    Aditya, N P; Espinosa, Yadira Gonzalez; Norton, Ian T

    2017-07-01

    Increased health risk associated with the sedentary life style is forcing the food manufacturers to look for food products with specific or general health benefits e.g. beverages enriched with nutraceuticals like catechin, curcumin rutin. Compounds like polyphenols, flavonoids, vitamins are the good choice of bioactive compounds that can be used to fortify the food products to enhance their functionality. However due to low stability and bioavailability of these bioactives (both hydrophobic and hydrophilic) within the heterogeneous food microstructure and in the Gastro Intestinal Tract (GIT), it becomes extremely difficult to pass on the real health benefits to the consumers. Recent developments in the application of nano-delivery systems for food product development is proving to be a game changer which has raised the expectations of the researchers, food manufacturers and consumers regarding possibility of enhancing the functionality of bioactives within the fortified food products. In this direction, nano/micro delivery systems using lipids, surfactants and other materials (carbohydrates, polymers, complexes, protein) have been fabricated to stabilize and enhance the biological activity of the bioactive compounds. In the present review, current status of the various delivery systems that are used for the delivery of hydrophilic bioactives and future prospects for using other delivery systems that have been not completely explored for the delivery of hydrophilic bioactives e.g. niosomes; bilosomes, cubosomes are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Rapid, simple, and cost-effective treatments to achieve long-term hydrophilic PDMS surfaces

    Science.gov (United States)

    Hemmilä, Samu; Cauich-Rodríguez, Juan V.; Kreutzer, Joose; Kallio, Pasi

    2012-10-01

    This paper describes rapid, simple, and cost-effective treatments for producing biocompatible and long-term hydrophilic polydimethylsiloxane (PDMS) surfaces identified in an experimental study investigating 39 treatments in all. The wetting of the surfaces was monitored during six months. Changes in surface morphology and chemical composition were also analyzed. Some of the treatments are presented here for the first time, while for earlier presented treatments the selection of investigated parameters was wider and the observation period for the surface wetting longer. The PDMS surfaces were modified by surface activation, physisorption, and synthesis of both “grafting to” and “grafting from” polymer brushes. In surface activation, the PDMS sample was exposed to oxygen plasma, with several combinations of exposure time and RF power. In the physisorption and synthesis of polymer brushes, three commercially available and biocompatible chemicals were used: 2-hydroxyethyl methacrylate (HEMA), polyethylene glycol (PEG), and polyvinylpyrrolidone (PVP). Thirty-three of the 39 treatments rendered the PDMS hydrophilic, and in 12 cases the hydrophilicity lasted at least six months. Seven of these long-term hydrophilic coatings supported a contact angle of 30° or less. Three of the long-lasting hydrophilic coatings required only minutes to prepare.

  3. Cell adhesion pattern created by OSTE polymers.

    Science.gov (United States)

    Liu, Wenjia; Li, Yiyang; Ding, Xianting

    2017-04-24

    Engineering surfaces with functional polymers is a crucial issue in the field of micro/nanofabrication and cell-material interface studies. For many applications of surface patterning, it does not need cells to attach on the whole surface. Herein, we introduce a novel polymer fabrication protocol of off-stoichiometry thiol-ene (OSTE) polymers to create heterogeneity on the surface by utilizing 3D printing and soft-lithography. By choosing two OSTE polymers with different functional groups, we create a pattern where only parts of the surface can facilitate cell adhesion. We also study the hydrophilic property of OSTE polymers by mixing poly(ethylene glycol) (PEG) directly with pre-polymers and plasma treatments afterwards. Moreover, we investigate the effect of functional groups' excess ratio and hydrophilic property on the cell adhesion ability of OSTE polymers. The results show that the cell adhesion ability of OSTE materials can be tuned within a wide range by the coupling effect of functional groups' excess ratio and hydrophilic property. Meanwhile, by mixing PEG with pre-polymers and undergoing oxygen plasma treatment afterward can significantly improve the hydrophilic property of OSTE polymers.

  4. Solution Behavior of Responsive Cationic Polymers

    OpenAIRE

    Karjalainen, Erno

    2015-01-01

    This thesis combines anion responsive polymeric ionic liquids (PILs) with thermoresponsive polymers. The polymers have been synthesized with controlled radical polymerization methods. A water-insoluble PIL was used as a macro-chain transfer agent in synthesis of block copolymers with poly(N-isopropyl acrylamide) (PNIPAm). PNIPAm chains of various lengths were grown to the same PIL-block. These polymers show a lower cirical solution temperature (LCST) type behavior, typical to PNIPAm. The...

  5. Hydrophilic quantum dots stability against an external low-strength electric field

    Energy Technology Data Exchange (ETDEWEB)

    Goftman, Valentina V., E-mail: Valentina.Goftman@UGent.be [Department of General and Inorganic Chemistry, Chemistry Institute, Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent (Belgium); Pankratov, Vladislav A.; Markin, Alexey V. [Department of General and Inorganic Chemistry, Chemistry Institute, Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Ginste, Dries Vande [IBCN/Electromagnetics Group, Department of Information Technology, Ghent University/iMinds, Sint-Pietersnieuwstraat 41, 9000 B-Gent (Belgium); De Saeger, Sarah [Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent (Belgium); Goryacheva, Irina Yu. [Department of General and Inorganic Chemistry, Chemistry Institute, Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation)

    2016-02-15

    Graphical abstract: - Highlights: • Silica-coated and polymer-covered hydrophilic quantum dots are synthesized and characterized. • Impact of low-strength electric field is compared for both hydrophilic shells. • Silica shell protects the quantum dots fluorescent core when being subjected to a low-strength electric field. - Abstract: Since the stability of nanobiolabels plays a key role in their application, we thoroughly investigated how an external, low-strength electric field impacts on the fluorescent properties of hydrophilic quantum dots (QDs). Two fundamentally different approaches were applied to make the QDs water-soluble, i.e. ligand exchange (namely silica covering) and encapsulation with an amphiphilic polymer. It is shown that, even under a low-strength electric field, the polymer-coated QDs could lose 90% of their brightness because of the weak interaction between the QD's surface and the polymeric molecule. Silica-covered QDs, on the contrary, stay bright and stable owing to the covalently attached dense silica shell. These findings, which are clearly explained and illustrated in the present paper, are of critical importance in the context of hydrophilic QDs’ bioapplication.

  6. Selection and production of insoluble xylan hydrolyzing enzyme by ...

    African Journals Online (AJOL)

    Forty-two strains of Thermomyces lanuginosus isolated from various sources in Thailand were divide into 4 groups based on the soluble xylan hydrolyzing (SXH) and insoluble xylan hydrolyzing (IXH) enzyme activities in the supernatant obtained from 5-day culture at 50°C in the liquid medium using corncob as substrate.

  7. Enzymatic lignocellulose hydrolysis: Improved cellulase productivity by insoluble solids recycling

    DEFF Research Database (Denmark)

    Weiss, Noah Daniel; Börjesson, Johan; Pedersen, Lars Saaby

    2013-01-01

    To take advantage of this effect, the amount of solids recycled should be maximized, based on a given processes ability to deal with higher solids concentrations and volumes. Recycling of enzymes by recycling the insoluble solids fraction was thus shown to be an effective method to decrease enzyme...

  8. TOOL FOR MONITORING HYDROPHILIC CONTAMINANTS ...

    Science.gov (United States)

    Global emissions of persistent bioconcentratable organic chemicals have resulted in a wide range of adverse ecological effects. Consequently, industry was led to develop less persistent, more water soluble, polar or hydrophilic organic compounds (HpOCs), which generally have low bioconcentration factors. However, evidence is growing that the large fluxes of these seemingly more environmentally friendly compounds (e.g., pesticides, prescription and non-prescription drugs, personal care and common consumer products, industrial and domestic-use chemicals and their degradation products) into aquatic systems on a world-wide basis may be responsible for incidents of acute toxicity and sub-lethal chronic abnormalities. These adverse effects include altered behavior, neurotoxicity, and severely impaired reproduction. Furthermore, the presence of these HpOCs likely plays a major role in the endocrine disrupting effects of complex mixtures of chemicals present in aquatic environments. In regard to physiological effects, pharmaceuticals are of particular concern because they are designed to elicit diverse pharmacological responses at very low doses. Unfortunately, the effects of this class of HpOCs on non-target, aquatic organisms are largely unknown. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are

  9. Hydrophilic-oleophobic stimuli-responsive materials and surfaces

    Science.gov (United States)

    Howarter, John A.

    Due to their high surface energy, hydrophilic surfaces are susceptible to contamination which is difficult to remove and often ruins the surface. Hydrophilic-oleophobic coatings have a diverse engineering potential including applications as self-cleaning surfaces, extended life anti-fog coatings, and environmental remediation in the selective filtration of oil-in-water mixtures. A successful design model for hydrophilic-oleophobic behavior has been developed using perfluorinated surfactants covalently bound to a surface. Within this design model, a variety of materials have been explored which the surfactants are covalently bound to a substrate; similarly, the surfactants may also be incorporated as a monomer into bulk copolymers. Surfactant based surfaces exhibited simultaneous hydrophilicity, necessary for anti-fogging, and oleophobicity, necessary for contamination resistance. The combination of these features rendered the surface as self-cleaning. Surfactant based brushes, composed of polyethylene glycol and perfluorinated constituents were grafted on to silica surfaces. The relationship between brush density and stimuli-responsiveness was determined by varying grafting conditions. The resultant surfaces were characterized with respect to chemical composition, brush thickness, and wetting behavior of water and hexadecane. Optimized surfaces exhibited stimuli-responsive behavior such that the surfaces will be wetted by water but not by oil. Surfactants were incorporated into random copolymers to create self-cleaning polymers which could be easily coated on to surfaces post-synthesis. Acrylic acid, methyl methacrylate, and hydroxyethyl methacrylate were used as comonomers; feed ratio was varied to establish compositional limits of stimuli-responsive behavior. Polymer composition dictated coating durability and self-cleaning performance as determined by water and hexadecane contact angle. The ability of select coatings to mitigate fogging was assessed in two

  10. Microencapsulation of a hydrophilic model molecule through vibration nozzle and emulsion phase inversion technologies.

    Science.gov (United States)

    Dorati, Rossella; Genta, Ida; Modena, Tiziana; Conti, Bice

    2013-01-01

    The goal of the present work was to evaluate and discuss vibration nozzle microencapsulation (VNM) technology combined to lyophilization, for the microencapsulation of a hydrophilic model molecule into a hydrophilic polymer. Fluorescein-loaded alginate microparticles prepared by VNM and emulsion phase inversion microencapsulation (EPIM) were lyophilized. Morphology, particle size distribution, lyophilized microspheres stability upon rehydration, drug loading and in vitro release were evaluated. Well-formed microspheres were obtained by the VNM technique, with higher yields of production (93.3-100%) and smaller particle size (d50138.10-158.00) than the EPIM microspheres. Rehydration upon lyophilization occurred in 30 min maintaining microsphere physical integrity. Fluorescein release was always faster from the microspheres obtained by VNM (364 h) than from those obtained by EPIM (504 h). The results suggest that VNM is a simple, easy to be scaled-up process suitable for the microencapsulation hydrophilic drugs.

  11. Polymer Conformation under Confinement

    Directory of Open Access Journals (Sweden)

    Stavros Bollas

    2017-02-01

    Full Text Available The conformation of polymer chains under confinement is investigated in intercalated polymer/layered silicate nanocomposites. Hydrophilic poly(ethylene oxide/sodium montmorillonite, PEO/Na+-MMT, hybrids were prepared utilizing melt intercalation with compositions where the polymer chains are mostly within the ~1 nm galleries of the inorganic material. The polymer chains are completely amorphous in all compositions even at temperatures where the bulk polymer is highly crystalline. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR is utilized to investigate the conformation of the polymer chains over a broad range of temperatures from below to much higher than the bulk polymer melting temperature. A systematic increase of the gauche conformation relatively to the trans is found with decreasing polymer content both for the C–C and the C–O bonds that exist along the PEO backbone indicating that the severe confinement and the proximity to the inorganic surfaces results in a more disordered state of the polymer.

  12. Design and Application of Nanogel-Based Polymer Networks

    Science.gov (United States)

    Dailing, Eric Alan

    Crosslinked polymer networks have wide application in biomaterials, from soft hydrogel scaffolds for cell culture and tissue engineering to glassy, high modulus dental restoratives. Composite materials formed with nanogels as a means for tuning network structure on the nanoscale have been reported, but no investigation into nanogels as the primary network component has been explored to this point. This thesis was dedicated to studying network formation from the direct polymerization of nanogels and investigating applications for these unique materials. Covalently crosslinked polymer networks were synthesized from polymerizable nanogels without the use of reactive small monomers or oligomers. Network properties were controlled by the chemical and physical properties of the nanogel, allowing for materials to be designed from nanostructured macromolecular precursors. Nanogels were synthesized from a thermally initiated solution free radical polymerization of a monomethacrylate, a dimethacrylate, and a thiol-based chain transfer agent. Monomers with a range of hydrophilic and hydrophobic character were copolymerized, and polymerizable groups were introduced through an alcohol-isocyanate click reaction. Nanogels were dispersible in water up to 75 wt%, including nanogels that contained a relatively high fraction of a conventionally water-insoluble component. Nanogels with molecular weights that ranged from 10's to 100's of kDa and hydrodynamic radii between 4 and 10 nm were obtained. Macroscopic crosslinked polymer networks were synthesized from the photopolymerization of methacrylate-functionalized nanogels in inert solvent, which was typically water. The nanogel composition and internal branching density affected both covalent and non-covalent interparticle interactions, which dictated the final mechanical properties of the networks. Nanogels with progressively disparate hydrophilic and hydrophobic character were synthesized to explore the potential for creating

  13. Soybean lecithin: acetone insoluble residue fractionation and their volatile components

    Directory of Open Access Journals (Sweden)

    Aly, Saadia M.

    2002-09-01

    Full Text Available The acetone insoluble residue was isolated from soybean lecithin. This residue was solvent fractionated resulted in four fractions, namely, acetic acid soluble, acetic acid insoluble, benzene phase and benzene insoluble phase. Concerning phospholipid constitution of these four fractions, it was found that the first fraction contains PC, PE and PI in percentages of 56.0, 21.6 and 19.0 respectively. The 2nd fraction makes 39 % PC and 60 % CER, besides some traces of PE and PI. The benzene phase is mainly all PC with some traces of PE. The last fraction is 80.6 % CER and 20 % PC. The fatty acid composition of these four fractions besides soluble in acetone, crude and degummed soybean oil and total phospholipids was recorded. Generally, it was found that the major saturated and unsaturated fatty acids were palmitic and linoleic. Volatile components of these samples except acetic acid insoluble were reported. Fourty nine compounds were separated. Thirty two components including aliphatic aldehydes, ketones, alcohols, esters and acids were identified. Aldehydes and ketones showed a changed through the seven samples. They increased by degumming.4,5-Dimethylelisoxazole had a strong lecithin like flavour, so it can be used as an indicator for the degumming process.2-Pentylfuran showed a significant decrease by degumming. Other compounds, such as esters and alcohols had no distinguish effect on the volatile products through process.El residuo insoluble en acetona fue aislado de la lecitina de soja. Este residuo fue fraccionado por solventes en cuatro fracciones: soluble en ácido acético, insoluble en ácido acético, fase benceno y fase insoluble en benceno. Concerniente a la constitución de los fosfolípidos de estas cuatro fracciones, se encontró que la primera fracción contiene PC, PE y PI en porcentajes del 56.0, 21.6 y 19.0 respectivamente. La segunda fracción tuvo 39 % PC y 60 % CER, junto a algunas trazas de PE y PI. La fase benceno est

  14. Relaciones agua-solutos-matriz insoluble en algunos sistemas alimentarios.

    OpenAIRE

    Chenoll Cuadros, Maria De La Creu

    2011-01-01

    Una gran parte de los alimentos estructurados pueden considerarse, de forma simplificada, constituidos por tres componentes: una matriz insoluble (que puede ser, por ejemplo, proteica, o compuesta por carbohidratos), agua y una serie de sólidos solubles (añadidos o no). Las relaciones de estos componentes entre sí, sus interacciones, y el modo en que varían durante determinados procesos industriales son factores que condicionan sus propiedades, tales como nutricionales y de calidad sensorial ...

  15. Enzymatic lignocellulose hydrolysis: Improved cellulase productivity by insoluble solids recycling

    Directory of Open Access Journals (Sweden)

    Weiss Noah

    2013-01-01

    Full Text Available Abstract Background It is necessary to develop efficient methods to produce renewable fuels from lignocellulosic biomass. One of the main challenges to the industrialization of lignocellulose conversion processes is the large amount of cellulase enzymes used for the hydrolysis of cellulose. One method for decreasing the amount of enzyme used is to recycle the enzymes. In this study, the recycle of enzymes associated with the insoluble solid fraction after the enzymatic hydrolysis of cellulose was investigated for pretreated corn stover under a variety of recycling conditions. Results It was found that a significant amount of cellulase activity could be recovered by recycling the insoluble biomass fraction, and the enzyme dosage could be decreased by 30% to achieve the same glucose yields under the most favorable conditions. Enzyme productivity (g glucose produced/g enzyme applied increased between 30 and 50% by the recycling, depending on the reaction conditions. While increasing the amount of solids recycled increased process performance, the methods applicability was limited by its positive correlation with increasing total solids concentrations, reaction volumes, and lignin content of the insoluble residue. However, increasing amounts of lignin rich residue during the recycle did not negatively impact glucose yields. Conclusions To take advantage of this effect, the amount of solids recycled should be maximized, based on a given processes ability to deal with higher solids concentrations and volumes. Recycling of enzymes by recycling the insoluble solids fraction was thus shown to be an effective method to decrease enzyme usage, and research should be continued for its industrial application.

  16. Hydrophilic surface modification of acrylate-based biomaterials.

    Science.gov (United States)

    Arnal-Pastor, M; Comín-Cebrián, S; Martínez-Ramos, C; Monleón Pradas, M; Vallés-Lluch, A

    2016-04-01

    Acrylic polymers have proved to be excellent with regard to cell adhesion, colonization and survival, in vitro and in vivo. Highly ordered and regular pore structures thereof can be produced with the help of polyamide templates, which are removed with nitric acid. This treatment converts a fraction of the ethyl acrylate side groups into acrylic acid, turning poly(ethyl acrylate) scaffolds into a more hydrophilic and pH-sensitive substrate, while its good biological performance remains intact. To quantify the extent of such a modification, and be able to characterize the degree of hydrophilicity of poly(ethyl acrylate), poly(ethyl acrylate) was treated with acid for different times (four, nine and 17 days), and compared with poly(acrylic acid) and a 90/10%wt. EA/AAc copolymer (P(EA-co-AAc)). The biological performance was also assessed for samples immersed in acid up to four days and the copolymer, and it was found that the incorporation of acidic units on the material surface was not prejudicial for cells. This surface modification of 3D porous hydrophobic scaffolds makes easier the wetting with culture medium and aqueous solutions in general, and thus represents an advantage in the manageability of the scaffolds. © The Author(s) 2016.

  17. Switchable Hydrophobic-Hydrophilic Surfaces

    CERN Document Server

    Bunker, B C; Huber, D L; Kent, M S; Kushmerick, J G; Lopez, G P; Manginell, R P; Méndez, S E; Yim, H

    2002-01-01

    Tethered films of poly n-isopropylacrylamide (PNIPAM) films have been developed as materials that can be used to switch the chemistry of a surface in response to thermal activation. In water, PNIPAM exhibits a thermally-activated phase transition that is accompanied by significant changes in polymer volume, water contact angle, and protein adsorption characteristics. New synthesis routes have been developed to prepare PNIPAM films via in-situ polymerization on self-assembled monolayers. Swelling transitions in tethered films have been characterized using a wide range of techniques including surface plasmon resonance, attenuated total reflectance infrared spectroscopy, interfacial force microscopy, neutron reflectivity, and theoretical modeling. PNIPAM films have been deployed in integrated microfluidic systems. Switchable PNIPAM films have been investigated for a range of fluidic applications including fluid pumping via surface energy switching and switchable protein traps for pre-concentrating and separating...

  18. Transmission of Soluble and Insoluble α-Synuclein to Mice

    Science.gov (United States)

    Jones, Daryl R.; Delenclos, Marion; Baine, AnnMarie T.; DeTure, Michael; Murray, Melissa E.; Dickson, Dennis W.; McLean, Pamela J.

    2015-01-01

    The neurodegenerative synucleinopathies, which include Parkinson disease, multiple system atrophy, and Lewy body disease, are characterized by the presence of abundant neuronal inclusions called Lewy bodies and Lewy neurites. These disorders remain incurable and a greater understanding of the pathologic processes is needed for effective treatment strategies to be developed. Recent data suggest that pathogenic misfolding of the presynaptic protein, α-synuclein (α-syn), and subsequent aggregation and accumulation is fundamental to the disease process. It is hypothesized that the misfolded isoform is able to induce misfolding of normal endogenous α-syn, much like what occurs in the prion diseases. Recent work highlighting the seeding effect of pathogenic α-syn has largely focused on the detergent-insoluble species of the protein. In this study we performed intracerebral inoculations of the sarkosyl-insoluble or sarkosyl-soluble fractions of human Lewy body disease brain homogenate and show that both fractions induce CNS pathology in mice at 4 months post-injection. Disease-associated deposits accumulated both near and distal to the site of the injection suggesting a cell-to-cell spread via recruitment of α-syn. These results provide further insight into the prion-like mechanisms of α-syn and suggest that disease-associated α-syn is not homogenous within a single patient but might exist in both soluble and insoluble isoforms. PMID:26574670

  19. Selective extraction and determination of chlorogenic acid in fruit juices using hydrophilic magnetic imprinted nanoparticles.

    Science.gov (United States)

    Hao, Yi; Gao, Ruixia; Liu, Dechun; He, Gaiyan; Tang, Yuhai; Guo, Zengjun

    2016-06-01

    In this paper, the novel hydrophilic magnetic molecularly imprinted nanoparticles were developed for selective separation and determination of chlorogenic acid in aqueous fruit juices. The polymers were prepared by using amino-functionalized magnetic nanoparticles as carriers, branched polyethyleneimine as functional monomer, and chlorogenic acid as template molecule. Branched polyethyleneimine with abundant active amino groups could react with template sufficiently, and its unique dendritic structure may amplify the number of the imprinted cavities. Meanwhile, it would improve the hydrophilicity of imprinted materials for attaining high extraction efficiency. The resulted polymers exhibit fast kinetics, high adsorption capacity, and favorable selectivity. In addition, the obtained nanoparticles were used as solid-phase extraction sorbents for selective isolation and determination of chlorogenic acid in peach, apple, and grape juices (0.92, 4.21, and 0.75 μg mL(-1), respectively). Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Mesoscopic simulations of hydrophilic cross-linked polycarbonate polyurethane networks: structure and morphology.

    Science.gov (United States)

    Iype, E; Esteves, A C C; de With, G

    2016-06-14

    Polyurethane (PU) cross-linked networks are frequently used in biomedical and marine applications, e.g., as hydrophilic polymer coatings with antifouling or low-friction properties and have been reported to exhibit characteristic phase separation between soft and hard segments. Understanding this phase-separation behavior is critical to design novel hydrophilic polymer coatings. However, most of the studies on the structure and morphology of cross-linked coatings are experimental, which only assess the phase separation via indirect methods. Herein we present a mesoscopic simulation study of the network characteristics of model hydrophilic polymer networks, consisting of PU with and without methyl-polyethylene glycol (mPEG) dangling chains. The systems are analyzed using a number of tools, such as the radial distribution function, the cross-link point density distribution and the Voronoi volume distribution (of the cross-linking points). The combined results show that the cross-linked networks without dangling chains are rather homogeneous but contain a small amount of clustering of cross-linker molecules. A clear phase separation is observed when introducing the dangling chains. In spite of that, the amount of cross-linker molecules connected to dangling chains only, i.e., not connected to the main network, is relatively small, leading to about 3 wt% extractables. Thus, these cross-linked polymers consist of a phase-separated, yet highly connected network. This study provides valuable guidelines towards new self-healing hydrophilic coatings based on the molecular design of cross-linked networks in direct contact with water or aqueous fluids, e.g., as anti-fouling self-repairing coatings for marine applications.

  1. Interactions between a polystyrene particle and hydrophilic and hydrophobic surfaces in aqueous solutions.

    Science.gov (United States)

    Thormann, Esben; Simonsen, Adam C; Hansen, Per L; Mouritsen, Ole G

    2008-07-15

    The interaction between a colloidal polystyrene particle mounted on an AFM cantilever and a hydrophilic and a hydrophobic surface in aqueous solution is investigated. Despite the apparent simplicity of these two types of systems a variety of different types of interactions are observed. The system containing the polystyrene particle and a hydrophilic surface shows DLVO-like interactions characteristic of forces between charged surfaces. However, when the surface is hydrophobized the interaction changes dramatically and shows evidence of a bridging air bubble being formed between the particle and the surface. For both sets of systems, plateaus of constant force in the force curves are obtained when the particle is retracted from the surface after being in contact. These events are interpreted as a number of individual polystyrene molecules that are bridging the polystyrene particle and the surface. The plateaus of constant force are expected for pulling a hydrophobic polymer in a bad (hydrophilic) solvent. The plateau heights are found to be of uniform spacing and independent of the type of surface, which suggests a model by which collapsed polymers are extended into the aqueous medium. This model is supported by a full stretching curve showing also the backbone elasticity and a stretching curve obtained in pentanol, where the plateau changes to a nonlinear force response, which is typical for a polymer in a good or neutral solvent. We suggest that these polymer bridges are important in particular for the interaction between polystyrene and the hydrophilic surface, where they to some extent counteract the long-range electrostatic repulsion.

  2. Hydrophilic excipients modulate the time lag of time-controlled disintegrating press-coated tablets

    OpenAIRE

    Lin, Shan-Yang; Li, Mei-Jane; Lin, Kung-Hsu

    2004-01-01

    An oral press-coated tablet was developed by means of direct compression to achieve the time-controlled disintegrating or rupturing function with a distinct predetermined lag time. This press-coated tablet containing sodium diclofenac in the inner core was formulated with an outer shell by different weight ratios of hydrophobic polymer of micronized ethylcellulose (EC) powder and hydrophilic excipients such as spray-dried lactose (SDL) or hydroxypropyl methylcellulose (HPMC). The effect of th...

  3. 21 CFR 201.319 - Water-soluble gums, hydrophilic gums, and hydrophilic mucilloids (including, but not limited to...

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Water-soluble gums, hydrophilic gums, and... Specific Labeling Requirements for Specific Drug Products § 201.319 Water-soluble gums, hydrophilic gums... been associated with the ingestion of water-soluble gums, hydrophilic gums, and hydrophilic mucilloids...

  4. Direct Photopatterning of Electrochromic Polymers

    DEFF Research Database (Denmark)

    Jensen, Jacob; Dyer, Aubrey L.; Shen, D. Eric

    2013-01-01

    Propylenedioxythiophene (ProDOT) polymers are synthesized using an oxidative polymerization route that results in methacrylate substituted poly(ProDOTs) having a Mn of 10–20 kDa wherein the methacrylate functionality constitutes from 6 to 60% of the total monomer units. Solutions of these polymers...... show excellent film forming abilities, with thin films prepared using both spray‐casting and spin‐coating. These polymers are demonstrated to crosslink upon UV irradiation at 350 nm, in the presence of an appropriate photoinitiator, to render the films insoluble to common organic solvents....... Electrochemical, spectroelectrochemical, and colorimetric analyses of the crosslinked polymer films are performed to establish that they retain the same electrochromic qualities as the parent polymers with no detriment to the observed properties. To demonstrate applicability for multi‐film processing...

  5. Nanostructured polymer membranes for proton conduction

    Science.gov (United States)

    Balsara, Nitash Pervez; Park, Moon Jeong

    2013-06-18

    Polymers having an improved ability to entrain water are characterized, in some embodiments, by unusual humidity-induced phase transitions. The described polymers (e.g., hydrophilically functionalized block copolymers) have a disordered state and one or more ordered states (e.g., a lamellar state, a gyroid state, etc.). In one aspect, the polymers are capable of undergoing a disorder-to-order transition while the polymer is exposed to an increasing temperature at a constant relative humidity. In some aspects the polymer includes a plurality of portions, wherein a first portion forms proton-conductive channels within the membrane and wherein the channels have a width of less than about 6 nm. The described polymers are capable of entraining and preserving water at high temperature and low humidity. Surprisingly, in some embodiments, the polymers are capable of entraining greater amounts of water with the increase of temperature. The polymers can be used in Polymer Electrolyte Membranes in fuel cells.

  6. Physiological function of insoluble dietary fiber prepared from exploded oak wood (Quercus mongolica).

    Science.gov (United States)

    Yang, Jae-Kyung; Choi, Myung-Suk; Kim, Chang-Joon; Shin, Yong-Seung; Han, Dae-Yong; Han, Sang-Woo; Lim, Bu-Kug; Lee, Jong-Yoon; Rhee, Soon-Jae; Kim, Eun-Hee; Kim, Gon-Sup

    2006-01-01

    This study investigated the production of insoluble dietary fiber using exploded and chemically treated oak wood (Quercus mongolica) and the physiological functions of prepared insoluble dietary fiber in laboratory animals. To produce high quality insoluble dietary fiber, the steam explosion treatment was performed at 25 kgf/cm2 pressure for 6 minutes. In the chemical analysis of insoluble dietary fiber, exploded oak wood was pretreated by 1% sodium hydroxide solution. The insoluble dietary fiber contained 7.6% residual lignin and 61.7% of alpha-cellulose. In order to compare the physiological functions of prepared insoluble dietary fiber with those of commercial insoluble dietary fiber, Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal diet and five high cholesterol diets, containing 1% cholesterol. The high cholesterol diet groups were classified as the fiber-free diet (FF group), 5% commercial alpha-cellulose diet group (5C group), 10% commercial alpha-cellulose group (10C group), 5% insoluble dietary fiber group (5M group) and 10% insoluble dietary fiber group (10M group). Food intake, weight gain and food efficiency ratio in high cholesterol groups were significantly higher than those of the normal group, but there were no significant differences among the high cholesterol diet groups. In addition, there were no significant differences in the weights of liver, kidney and small intestine in insoluble dietary fiber-supplemented groups. Cecum weights in all insoluble dietary fiber groups were significantly higher than those of the FF group. There were no significant differences in the activities of the glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) among the insoluble dietary fiber-supplemented groups. In conclusion, the prepared insoluble dietary fiber and the commercially available insoluble fiber showed the same physiological effects. Moreover, the preparation method for the insoluble dietary

  7. Hot-melt extruded filaments based on pharmaceutical grade polymers for 3D printing by fused deposition modeling.

    Science.gov (United States)

    Melocchi, Alice; Parietti, Federico; Maroni, Alessandra; Foppoli, Anastasia; Gazzaniga, Andrea; Zema, Lucia

    2016-07-25

    Fused deposition modeling (FDM) is a 3D printing technique based on the deposition of successive layers of thermoplastic materials following their softening/melting. Such a technique holds huge potential for the manufacturing of pharmaceutical products and is currently under extensive investigation. Challenges in this field are mainly related to the paucity of adequate filaments composed of pharmaceutical grade materials, which are needed for feeding the FDM equipment. Accordingly, a number of polymers of common use in pharmaceutical formulation were evaluated as starting materials for fabrication via hot melt extrusion of filaments suitable for FDM processes. By using a twin-screw extruder, filaments based on insoluble (ethylcellulose, Eudragit(®) RL), promptly soluble (polyethylene oxide, Kollicoat(®) IR), enteric soluble (Eudragit(®) L, hydroxypropyl methylcellulose acetate succinate) and swellable/erodible (hydrophilic cellulose derivatives, polyvinyl alcohol, Soluplus(®)) polymers were successfully produced, and the possibility of employing them for printing 600μm thick disks was demonstrated. The behavior of disks as barriers when in contact with aqueous fluids was shown consistent with the functional application of the relevant polymeric components. The produced filaments were thus considered potentially suitable for printing capsules and coating layers for immediate or modified release, and, when loaded with active ingredients, any type of dosage forms. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Spatially resolved spectroscopic differentiation of hydrophilic and hydrophobic domains on individual insulin amyloid fibrils

    DEFF Research Database (Denmark)

    Deckert-Gaudig, Tanja; Kurouski, Dmitry; Hedegaard, Martin A B

    2016-01-01

    on the identification of the secondary structure via the amide III band and the differentiation of hydrophobic and hydrophilic domains on the surface. In addition multivariate data analysis, specifically the N-FINDR procedure, was employed to generate structure-specific maps. The ability of TERS to localize specific......The formation of insoluble β-sheet-rich protein structures known as amyloid fibrils is associated with numerous neurodegenerative diseases, such as Alzheimer's and Parkinson's disease. A detailed understanding of the molecular structure of the fibril surface is of interest as the first contact...... with the physiological environment in vivo and plays a decisive role in biological activity and associated toxicity. Recent studies reveal that the inherent sensitivity and specificity of tip-enhanced Raman scattering (TERS) renders this technique a compelling method for fibril surface analysis at the single...

  9. Oscillatory thermocapillary instability in liquid layer with insoluble surfactant

    Science.gov (United States)

    Allias, Razihan; Nasir, Mohd. Agos Salim; Kechil, Seripah Awang

    2017-11-01

    Oscillatory convective flow is undesirable because it can produce bubbles, striation and dendrites in the manufactured products. The ability to control the complex convective flow patterns is important in technological processes and fundamental science. One of the factors that can alter the dynamics of the surface tension of thin fluid film is the surface-active agents. In this work, the influence of the insoluble surface-active agents on thermocapillary convective instability in a liquid layer for non-deformable free surface is examined. Uniform temperature and uniform heat flux for the temperature condition at the bottom surface are considered. The linear stability analysis is used to assess the effects of elasticity number, Lewis number, Prandtl number and Biot number on the onset of oscillatory convection. The existence of insoluble surfactant stabilizes the fluid layer system. The system is more stable in the case of uniform temperature. The presence of surfactant and temperature setting at the bottom boundary can suppress the onset of oscillatory instability.

  10. Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces

    Science.gov (United States)

    Dussinger, Peter M.; Lindemuth, James E.

    1997-01-01

    The principal objective of this Phase 2 SBIR program was to develop and demonstrate a practically insoluble coating for nickel-based superalloys for Stirling engine heat pipe applications. Specific technical objectives of the program were: (1) Determine the solubility corrosion rates for Nickel 200, Inconel 718, and Udimet 72OLI in a simulated Stirling engine heat pipe environment, (2) Develop coating processes and techniques for capillary groove and screen wick structures, (3) Evaluate the durability and solubility corrosion rates for capillary groove and screen wick structures coated with an insoluble coating in cylindrical heat pipes operating under Stirling engine conditions, and (4) Design and fabricate a coated full-scale, partial segment of the current Stirling engine heat pipe for the Stirling Space Power Convertor program. The work effort successfully demonstrated a two-step nickel aluminide coating process for groove wick structures and interior wall surfaces in contact with liquid metals; demonstrated a one-step nickel aluminide coating process for nickel screen wick structures; and developed and demonstrated a two-step aluminum-to-nickel aluminide coating process for nickel screen wick structures. In addition, the full-scale, partial segment was fabricated and the interior surfaces and wick structures were coated. The heat pipe was charged with sodium, processed, and scheduled to be life tested for up to ten years as a Phase 3 effort.

  11. Synthesis of Hydrophilic and Amphiphilic Acryl Sucrose Monomers and Their Copolymerisation with Styrene, Methylmethacrylate and α- and β-Pinenes

    Directory of Open Access Journals (Sweden)

    Maria Teresa Barros

    2010-04-01

    Full Text Available Herein, we report the synthesis of monomethacryloyl sucrose esters, and their successful free radical homo- and co-polymerisation with styrene, methylmethacrylate, α- and β-pinene. The chemical, physical, structural and surface chemical properties of these polymers, containing a hydrophobic olefin backbone and hydrophilic sugar moieties as side chains, have been investigated. Biodegradation tests of the copolymer samples by a microbial fungal culture (Aspergillus niger method showed good biodegradability. The chemical structure and surface chemistry of the synthesized homo- and co-polymers demonstrate their potential technological relevance as amphiphilic and biodegradable polymers.

  12. Hydrophobic-hydrophilic forces in protein folding.

    Science.gov (United States)

    Durell, Stewart R; Ben-Naim, Arieh

    2017-08-01

    The process of protein folding is obviously driven by forces exerted on the atoms of the amino-acid chain. These forces arise from interactions with other parts of the protein itself (direct forces), as well as from interactions with the solvent (solvent-induced forces). We present a statistical-mechanical formalism that describes both these direct and indirect, solvent-induced thermodynamic forces on groups of the protein. We focus on 2 kinds of protein groups, commonly referred to as hydrophobic and hydrophilic. Analysis of this result leads to the conclusion that the forces on hydrophilic groups are in general stronger than on hydrophobic groups. This is then tested and verified by a series of molecular dynamics simulations, examining both hydrophobic alkanes of different sizes and hydrophilic moieties represented by polar-neutral hydroxyl groups. The magnitude of the force on assemblies of hydrophilic groups is dependent on their relative orientation: with 2 to 4 times larger forces on groups that are able to form one or more direct hydrogen bonds. © 2017 Wiley Periodicals, Inc.

  13. Hydrophilic fluorescent nanogel thermometer for intracellular thermometry.

    Science.gov (United States)

    Gota, Chie; Okabe, Kohki; Funatsu, Takashi; Harada, Yoshie; Uchiyama, Seiichi

    2009-03-04

    The first methodology to measure intracellular temperature is described. A highly hydrophilic fluorescent nanogel thermometer developed for this purpose stays in the cytoplasm and emits stronger fluorescence at a higher temperature. Thus, intracellular temperature variations associated with biological processes can be monitored by this novel thermometer with a temperature resolution of better than 0.5 degrees C.

  14. Conjugated Polymer Nanoparticles for Bioimaging

    Directory of Open Access Journals (Sweden)

    Yasmine Braeken

    2017-12-01

    Full Text Available During the last decade, conjugated polymers have emerged as an interesting class of fluorescence imaging probes since they generally show high fluorescence brightness, high photostability, fast emission rates, non-blinking behavior and low cytotoxicity. The main concern related to most conjugated polymers is their lack of hydrophilicity and thereby poor bio-availability. This can, however, be overcome by the formulation of conjugated polymer nanoparticles in aqueous medium. This review provides an overview of the different techniques employed for the preparation of conjugated polymer nanoparticles, together with methods to improve their photoluminescence quantum yields. For selective targeting of specific cells, dedicated surface functionalization protocols have been developed, using different functional groups for ligand immobilization. Finally, conjugated polymer nanoparticles have recently also been employed for theranostic applications, wherein the particles are simultaneously used as fluorescent probes and carriers for anti-tumor drugs.

  15. Effects of resin hydrophilicity on water sorption and changes in modulus of elasticity.

    Science.gov (United States)

    Ito, Shuichi; Hashimoto, Masanori; Wadgaonkar, Bakul; Svizero, Nadia; Carvalho, Ricardo M; Yiu, Cynthia; Rueggeberg, Frederick A; Foulger, Stephen; Saito, Takashi; Nishitani, Yoshihiro; Yoshiyama, Masahiro; Tay, Franklin R; Pashley, David H

    2005-11-01

    As acidic monomers of self-etching adhesives are incorporated into dental adhesives at high concentrations, the adhesive becomes more hydrophilic. Water sorption by polymers causes plasticization and lowers mechanical properties. The purpose of this study was to compare the water sorption and modulus of elasticity (E) of five experimental neat resins (EX) of increasing hydrophilicity, as ranked by their Hoy's solubility parameters and five commercial resins. After measuring the initial modulus of all resin disks by biaxial flexure, half the specimens were stored in hexadecane and the rest were stored in water. Repeated measurements of stiffness were made for 3 days. Water sorption and solubility measurements were made in a parallel experiment. None of the specimens stored in oil showed any significant decrease in modulus. All resins stored in water exhibited a time-dependent decrease in modulus that was proportional to their degree of water sorption. Water sorption of EX was proportional to Hoy's solubility parameter for polar forces (delta(p)) with increasing polarity resulting in higher sorption. The least hydrophilic resin absorbed 0.55 wt% water and showed a 15% decrease in modulus after 3 days. The most hydrophilic experimental resin absorbed 12.8 wt% water and showed a 73% modulus decrease during the same period. The commercial resins absorbed between 5% and 12% water that was associated with a 19-42% reduction in modulus over 3 days.

  16. Radius ratio rule for surface hydrophilization of polydimethyl siloxane and silica nanoparticle composite

    Energy Technology Data Exchange (ETDEWEB)

    Toutam, Vijaykumar, E-mail: toutamvk@nplindia.org [Quantum Phenomena and Applications Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Jain, Puneet; Sharma, Rina [Quantum Phenomena and Applications Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Bathula, Sivaiah; Dhar, Ajay [Material Physics and Engineering Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India)

    2015-09-15

    Graphical abstract: - Highlights: • Binary hard sphere silica nanoparticle system based PDMS composite. • Enhanced hydrophilization and retainability of the composite. • Restriction of uncured PDMS from diffusion. • Increased Debye length of electrostatic double layer, measured by F-D Spectroscopy. - Abstract: Polydimethyl siloxane (PDMS) and Silica (SiO{sub 2}) nanoparticle composite blocks of three different batches (CB1–CB3) made by varying the size of SiO{sub 2} nanoparticles (NP), are studied for the degree of hydrophilization and retainability after oxidation by contact angle measurements (CA) and force distance spectroscopy (FDS) using Atomic Force Microscope (AFM). While CA measurements have shown high hydrophilization and retainability for CB3, F-D spectroscopy has reiterated the observation and has shown long range interactive forces and high Debye length of the electrostatic double layer formed. These results are in agreement with the radius ratio rule of binary sphere system for high density packing in the composite and thereby for strong hydrophilization and retainability due to reinforcement and restricted diffusion of uncured polymer.

  17. Applications of redox polymers in biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Boguslavsky, L. (Moltech Corporation, Stony Brook, NY (United States)); Hale, P.D. (Moltech Corporation, Stony Brook, NY (United States)); Geng Lin (Moltech Corporation, Stony Brook, NY (United States)); Skotheim, T.A. (Moltech Corporation, Stony Brook, NY (United States)); Lee Hongsui (Dept. of Applied Science, Brookhaven National Lab., Upton, NY (United States))

    1993-03-01

    Polymers containing covalently attached redox molecules can be highly effective electron transfer mediators for flavin adenine dinucleotide redox centers of many oxidases. Highly flexible siloxane and ethylene oxide polymers containing covalently attached ferrocene molecules are shown to be capable of mediating electron transfer between enzymes and an electrode. The construction and response of bienzyme cholesterol biosensor, acetylcholine and glucose biosensor are described and discussed. Our data showed that the flexibility, hydrophilicity of the polymer, the density of redox centers in the polymer matrices and the self-exchange reaction rate of the redox molecules control the efficiency of the electron transfer mediation. (orig.)

  18. Morphological Study of Insoluble Organic Matter Residues from Primitive

    Science.gov (United States)

    Changela, H. G.; Stroud, R. M.; Peeters, Z.; Nittler, L. R.; Alexander, C. M. O'D.; DeGregorio, B. T.; Cody, G. D.

    2012-01-01

    Insoluble organic matter (IOM) constitutes a major proportion, 70-99%, of the total organic carbon found in primitive chondrites [1, 2]. One characteristic morphological component of IOM is nanoglobules [3, 4]. Some nanoglobules exhibit large N-15 and D enrichments relative to solar values, indicating that they likely originated in the ISM or the outskirts of the protoplanetary disk [3]. A recent study of samples from the Tagish Lake meteorite with varying levels of hydrothermal alteration suggest that nanoglobule abundance decreases with increasing hydrothermal alteration [5]. The aim of this study is to further document the morphologies of IOM from a range of primitive chondrites in order to determine any correlation of morphology with petrographic grade and chondrite class that could constrain the formation and/or alteration mechanisms.

  19. Mechanically stable insoluble titanium-lead anodes for sulfate electrolytes

    Directory of Open Access Journals (Sweden)

    Chmiola J.

    2003-01-01

    Full Text Available Different formulations of a new material to be used as an insoluble anode for copper electrowinning, a Ti-Pb composite, were investigated for both mechanical and electrochemical properties. Mechanical and metallographic characteristic tests, as well as short-term deposition tests were used to study the effect of the Ti/Pb ratio on anode performance. Yield strength and elastic modulus, obtained through tensile testing, significantly exceed that of lead. Metallographic procedures were used to assess the uniformity of lead distribution in the material, as well as porosity, which would be decreased below 1 % for most of the compositions under study. Short-term deposition tests were used to determine power consumption, deposit quality current efficiency and weight loss characteristics of the new anode material. The material with only 30 vol.% lead shows approximately the same electrochemical performance as a pure lead anode, but has much higher mechanical properties which prevent warping and extend the lifetime of the anode.

  20. Solvent vapor annealing of an insoluble molecular semiconductor

    KAUST Repository

    Amassian, Aram

    2010-01-01

    Solvent vapor annealing has been proposed as a low-cost, highly versatile, and room-temperature alternative to thermal annealing of organic semiconductors and devices. In this article, we investigate the solvent vapor annealing process of a model insoluble molecular semiconductor thin film - pentacene on SiO 2 exposed to acetone vapor - using a combination of optical reflectance and two-dimensional grazing incidence X-ray diffraction measurements performed in situ, during processing. These measurements provide valuable and new insight into the solvent vapor annealing process; they demonstrate that solvent molecules interact mainly with the surface of the film to induce a solid-solid transition without noticeable swelling, dissolving or melting of the molecular material. © 2010 The Royal Society of Chemistry.

  1. Secreted expression of Leuconostoc mesenteroides glucansucrase in Lactococcus lactis for the production of insoluble glucans.

    Science.gov (United States)

    Skory, Christopher D; Côté, Gregory L

    2015-12-01

    We expressed a glucansucrase, DsrI, from Leuconostoc mesenteroides that catalyzes formation of water-insoluble glucans from sucrose using a nisin-controlled gene expression system in Lactococcus lactis. These polymers have potential for production of biodegradable gels, fibers, and films. We optimized production of DsrI using several different background vectors, signal peptides, strains, induction conditions, and bioreactor parameters to increase extracellular accumulation. Optimal production of the enzyme utilized a high-copy plasmid, pMSP3535H3, which contains a nisin immunity gene, L. lactis LM0230, and bioreactors maintained at pH 6.0 to stabilize the enzyme. We were able to significantly improve growth using the lactic acid inhibitor heme and by continuous removal of lactic acid with anion exchange resins, but enzyme production was less than the controls. The recombinant enzyme under optimized conditions accumulated in the culture medium to approximately 380 mg/L, which was over 150-fold higher compared to the native L. mesenteroides strain. Methods are also included for purification of DsrI utilizing the glucan-binding domain of the enzyme.

  2. Insoluble glycogen, a metabolizable internal adsorbent, decreases the lethality of endotoxin shock in rats

    Directory of Open Access Journals (Sweden)

    S. Sipka

    1997-01-01

    Full Text Available Insoluble glycogen is an enzymatically modified form of naturally occurring soluble glycogen with a great adsorbing capacity. It can be metabolized by phagocytes to glucose. In this study we used insoluble glycogen intravenously in the experimental endotoxin shock of rats. Wistar male rats were sensitized to endotoxin by Pb acetate. The survival of rats were compared in groups of animals endotoxin shock treated and non-treated with insoluble glycogen. Furthermore, we have determined in vitro the binding capacity of insoluble glycogen for endotoxin, tumour necrosis factor alpha, interleukin-1 and secretable phospholipase A2. Use of 10 mg/kg dose of insoluble glycogen could completely prevent the lethality of shock induced by LD50 quantity of endotoxin in rats. All animals treated survived. Insoluble glycogen is a form of ‘metabolizable internal adsorbents’. It can potentially be used for treatment of septic shock.

  3. 21 CFR 886.5925 - Soft (hydrophilic) contact lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Soft (hydrophilic) contact lens. 886.5925 Section 886.5925 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5925 Soft (hydrophilic) contact lens. (a) Identification. A soft (hydrophilic)...

  4. 21 CFR 878.4018 - Hydrophilic wound dressing.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4018 Hydrophilic wound dressing. (a) Identification. A hydrophilic wound dressing is a sterile or non-sterile device intended to cover... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydrophilic wound dressing. 878.4018 Section 878...

  5. Competitive protein adsorption to polymer surface from human serum

    DEFF Research Database (Denmark)

    Holmberg, Maria; Jensen, Karin Bagger Stibius; Larsen, Niels Bent

    2008-01-01

    Surface modification by "soft" plasma polymerisation to obtain a hydrophilic and non-fouling polymer surface has been validated using radioactive labelling. Adsorption to unmodified and modified polymer surfaces, from both single protein and human serum solutions, has been investigated. By using...

  6. Condensing Heat Exchanger with Hydrophilic Antimicrobial Coating

    Science.gov (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor)

    2014-01-01

    A multi-layer antimicrobial hydrophilic coating is applied to a substrate of anodized aluminum, although other materials may form the substrate. A silver layer is sputtered onto a thoroughly clean anodized surface of the aluminum to about 400 nm thickness. A layer of crosslinked, silicon-based macromolecular structure about 10 nm thickness overlies the silver layer, and the outermost surface of the layer of crosslinked, silicon-based macromolecular structure is hydroxide terminated to produce a hydrophilic surface with a water drop contact angle of less than 10.degree.. The coated substrate may be one of multiple fins in a condensing heat exchanger for use in the microgravity of space, which has narrow channels defined between angled fins such that the surface tension of condensed water moves water by capillary flow to a central location where it is pumped to storage. The antimicrobial coating prevents obstruction of the capillary passages.

  7. Fate of SDS-insoluble glutenin polymers from semolina to dry pasta.

    Science.gov (United States)

    Joubert, Marianne; Lullien-Pellerin, Valérie; Morel, Marie-Hélène

    2018-02-01

    Pasta cooking quality is well known to be related to semolina protein content and composition, however impact of the unextractable polymeric protein content (%UPP) remains disputed. In this work different semolina samples, of variable protein contents (10.5-14.2%) and %UPP (20.2-46.3%) are studied. The changes in %UPP induced by the successive pasta processing steps (mixing, extrusion, drying) but also those occurring during resting periods at 35°C, applied in-between them, were investigated. Effect of a resting period was moderate after mixing, but pronounced after extrusion. Resting of extruded pasta at 35°C significantly increased %UPP, which can even grow beyond that of the semolina. No relationship was found between pasta viscoelastic index (VI) and semolina %UPP or protein content. However, cooked pasta VI was found related to the calculated %UPP of rested fresh pasta. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Highly Sensitive and Selective Gas Sensor Using Hydrophilic and Hydrophobic Graphenes

    Science.gov (United States)

    Some, Surajit; Xu, Yang; Kim, Youngmin; Yoon, Yeoheung; Qin, Hongyi; Kulkarni, Atul; Kim, Taesung; Lee, Hyoyoung

    2013-06-01

    New hydrophilic 2D graphene oxide (GO) nanosheets with various oxygen functional groups were employed to maintain high sensitivity in highly unfavorable environments (extremely high humidity, strong acidic or basic). Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time. The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors. The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor.

  9. Effects of Toasting Time on Digestive Hydrolysis of Soluble and Insoluble 00-Rapeseed Meal Proteins.

    Science.gov (United States)

    Salazar-Villanea, Sergio; Bruininx, Erik M A M; Gruppen, Harry; Carré, Patrick; Quinsac, Alain; van der Poel, Antonius F B

    2017-01-01

    Thermal damage to proteins can reduce their nutritional value. The effects of toasting time on the kinetics of hydrolysis, the resulting molecular weight distribution of 00-rapeseed meal (RSM) and the soluble and insoluble protein fractions separated from the RSM were studied. Hydrolysis was performed with pancreatic proteases to represent in vitro protein digestibility. Increasing the toasting time of RSM linearly decreased the rate of protein hydrolysis of RSM and the insoluble protein fractions. The extent of hydrolysis was, on average, 44% higher for the insoluble compared with the soluble protein fraction. In contrast, the rate of protein hydrolysis of the soluble protein fraction was 3-9-fold higher than that of the insoluble protein fraction. The rate of hydrolysis of the insoluble protein fraction linearly decreased by more than 60% when comparing the untoasted to the 120 min toasted RSM. Increasing the toasting time elicited the formation of Maillard reaction products (furosine, N(ε)-carboxymethyl-lysine and N(ε)-carboxyethyl-lysine) and disulfide bonds in the insoluble protein fraction, which is proposed to explain the reduction in the hydrolysis rate of this fraction. Overall, longer toasting times increased the size of the peptides resulting after hydrolysis of the RSM and the insoluble protein fraction. The hydrolysis kinetics of the soluble and insoluble protein fractions and the proportion of soluble:insoluble proteins in the RSM explain the reduction in the rate of protein hydrolysis observed in the RSM with increasing toasting time.

  10. Hydrophilic PEO-PDMS for microfluidic applications

    Science.gov (United States)

    Yao, Mingjin; Fang, Ji

    2012-02-01

    Polydimethylsiloxane (PDMS) is a popularly used nontoxic and biocompatible material in microfluidic systems, which is relatively cheap and does not break easily like glass. The simple fabrication, optical transparency and elastomeric property make PDMS a handy material to work with. In order to develop different applications of PDMS in microfluidics and bioengineering, it is necessary to modify the PDMS surface nature to improve wetting characteristics, and to have a better control in nonspecific binding of proteins and cells, as well as to increase adhesion. At the moment, the hydrophilic surface modification performance of PDMS is known to recover its hydrophobicity shortly after oxidation modification, which is not stable in the long term (Owen and Smith 1994 J. Adhes. Sci. Technol. 8 1063-75). This paper presents a long-term stable hydrophilic surface modification processing of PDMS. The poly(dimethylsiloxane-ethylene oxide polymeric) (PDMS-b-PEO) is used in this project as a surfactant additive to be added into the PDMS base and the curing agent mixture during polymerization and to create hydrophilic PEO-PDMS. The contact angle can be controlled at 21.5-80.9° with the different mixing ratios and the hydrophilicity will remain stable for two months and then slightly varied later. We also investigate the bonding conditions of the modified PDMS to a silicon wafer and a glass wafer. To demonstrate its applications, we designed a device which consists of microchannels on a silicon wafer, and PEO-PDMS is utilized as a cover sheet. The capillary function was investigated under the different contact angles of PED-PDMS and with different aspect ratios of microchannels. All of the processes and testing data are presented in detail. This easy and cost-effective modified PDMS with a good bonding property can be widely used in the capillary device and systems, and microfluidic devices for fluid flow control of the microchannels in biological, chemical, medical

  11. Polymer Design and Processing for Liquid-Core waveguides

    DEFF Research Database (Denmark)

    Sagar, Kaushal Shashikant

    precursor material. Upon attaining thermodynamically stable gyroid phase segregation, nanoporosity is induced by chemically removing PDMS, the so-called sacrificial block. The isotropic nanoporosity in the polymer is utilized in fabricating a novel type of waveguides for opto-fluidic applications, which we...... call solid-liquid core waveguides, shortly SLCW. The high refractive index core of a SLCW consists of nanoporous polymer (solid) rendered hydrophilic and filled with water (liquid), while the low refractive index cladding consists of air-filled hydrophobic nanoporous polymer. Under conditions of total...... internal reflection, light is confined within the solid-liquid core. Controlled regions of the originally hydrophobic nanoporous 1,2-PB are rendered hydrophilic by photochemical modification of the polymer in the presence of photolithographic masks. In contact with water the hydrophilic regions...

  12. Thermally stable and chemically resistant polymer membranes : aromatic polyoxadiazoles and polytriazoles

    OpenAIRE

    Gebben, Bert

    1988-01-01

    This thesis concerns the preparation of membranes from thermally stable and chemically resistant polymers. Two polymer families from the category of heterocyclic and aromatic polymers have been selected for investigation, the polyoxadiazoles and the polytriazoles, respectively. A major problem concerning these types of polymers is their bad processability due to their insolubility and infusibility. For the polyoxadiazoles this problem is circumvented by using a two-step preparation process th...

  13. Elevated Performance of Thin Film Nanocomposite Membranes Enabled by Modified Hydrophilic MOFs for Nanofiltration.

    Science.gov (United States)

    Zhu, Junyong; Qin, Lijuan; Uliana, Adam; Hou, Jingwei; Wang, Jing; Zhang, Yatao; Li, Xin; Yuan, Shushan; Li, Jian; Tian, Miaomiao; Lin, Jiuyang; Van der Bruggen, Bart

    2017-01-18

    Metal-organic frameworks (MOFs) are studied for the design of advanced nanocomposite membranes, primarily due to their ultrahigh surface area, regular and highly tunable pore structures, and favorable polymer affinity. However, the development of engineered MOF-based membranes for water treatment lags behind. Here, thin-film nanocomposite (TFN) membranes containing poly(sodium 4-styrenesulfonate) (PSS) modified ZIF-8 (mZIF) in a polyamide (PA) layer were constructed via a facile interfacial polymerization (IP) method. The modified hydrophilic mZIF nanoparticles were evenly dispersed into an aqueous solution comprising piperazine (PIP) monomers, followed by polymerizing with trimesoyl chloride (TMC) to form a composite PA film. FT-IR spectroscopy and XPS analyses confirm the presence of mZIF nanoparticles on the top layer of the membranes. SEM and AFM images evince a retiform morphology of the TFN-mZIF membrane surface, which is intimately linked to the hydrophilicity and adsorption capacity of mZIF nanoparticles. Furthermore, the effect of different ZIF-8 loadings on the overall membrane performance was studied. Introducing the hydrophilizing mZIF nanoparticles not only furnishes the PA layer with a better surface hydrophilicity and more negative charge but also more than doubles the original water permeability, while maintaining a high retention of Na2SO4. The ultrahigh retentions of reactive dyes (e.g., reactive black 5 and reactive blue 2, >99.0%) for mZIF-functionalized PA membranes ensure their superior nanofiltration performance. This facile, cost-effective strategy will provide a useful guideline to integrate with other modified hydrophilic MOFs to design nanofiltration for water treatment.

  14. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    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.

  15. Soluble and insoluble signals sculpt osteogenesis in angiogenesis

    Science.gov (United States)

    Ripamonti, Ugo

    2010-01-01

    The basic tissue engineering paradigm is tissue induction and morphogenesis by combinatorial molecular protocols whereby soluble molecular signals are combined with insoluble signals or substrata. The insoluble signal acts as a three-dimensional scaffold for the initiation of de novo tissue induction and morphogenesis. The osteogenic soluble molecular signals of the transforming growth factor-β (TGF-β) supergene family, the bone morphogenetic/osteogenic proteins (BMPs/OPs) and, uniquely in the non-human primate Papio ursinus (P. ursinus), the three mammalian TGF-β isoforms induce bone formation as a recapitulation of embryonic development. In this paper, I discuss the pleiotropic activity of the BMPs/OPs in the non-human primate P. ursinus, the induction of bone by transitional uroepithelium, and the apparent redundancy of molecular signals initiating bone formation by induction including the three mammalian TGF-β isoforms. Amongst all mammals tested so far, the three mammalian TGF-β isoforms induce endochondral bone formation in the non-human primate P. ursinus only. Bone tissue engineering starts by erecting scaffolds of biomimetic biomaterial matrices that mimic the supramolecular assembly of the extracellular matrix of bone. The molecular scaffolding lies at the hearth of all tissue engineering strategies including the induction of bone formation. The novel concept of tissue engineering is the generation of newly formed bone by the implantation of “smart” intelligent biomimetic matrices that per se initiate the ripple-like cascade of bone differentiation by induction without exogenously applied BMPs/OPs of the TGF-β supergene family. A comprehensive digital iconographic material presents the modified tissue engineering paradigm whereby the induction of bone formation is initiated by intelligent smart biomimetic matrices that per se initiate the induction of bone formation without the exogenous application of the soluble osteogenic molecular signals

  16. Insoluble coatings for Stirling engine heat pipe condenser surfaces

    Science.gov (United States)

    Dussinger, Peter M.

    1993-09-01

    The work done by Thermacore, Inc., Lancaster, Pennsylvania, for the Phase 1, 1992 SBIR National Aeronautics and Space Administration Contract, 'Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces' is described. The work was performed between January 1992 and July 1992. Stirling heat engines are being developed for electrical power generation use on manned and unmanned earth orbital and planetary missions. Dish Stirling solar systems and nuclear reactor Stirling systems are two of the most promising applications of the Stirling engine electrical power generation technology. The sources of thermal energy used to drive the Stirling engine typically are non-uniform in temperature and heat flux. Liquid metal heat pipe receivers are used as thermal transformers and isothermalizers to deliver the thermal energy at a uniform high temperature to the heat input section of the Stirling engine. The use of a heat pipe receiver greatly enhances system efficiency and potential life span. One issue that is raised during the design phase of heat pipe receivers is the potential solubility corrosion of the Stirling engine heat input section by the liquid metal working fluid. This Phase 1 effort initiated a program to evaluate and demonstrate coatings, applied to nickel based Stirling engine heater head materials, that are practically 'insoluble' in sodium, potassium, and NaK. This program initiated a study of nickel aluminide as a coating and developed and demonstrated a heat pipe test vehicle that can be used to test candidate materials and coatings. Nickel 200 and nickel aluminide coated Nickel 200 were tested for 1000 hours at 800 C at a condensation heat flux of 25 W/sq cm. Subsequent analyses of the samples showed no visible sign of solubility corrosion of either coated or uncoated samples. The analysis technique, photomicrographs at 200X, has a resolution of better than 2.5 microns (.0001 in). The results indicate that the heat pipe environment is not directly

  17. Stabilizing Co-continuous Morphologies in Polymer Blends with Particles

    Science.gov (United States)

    Asoo, B. Y.; Fredrickson, G. H.; Kramer, E. J.

    2001-03-01

    Recent discoveries in polymer processing by CSP Technologies have led to the production of molded polymer parts that possess a significant capacity for moisture absorption. The materials are manufactured by melt compounding three components: a majority hydrophobic polymer (e.g. a polyolefin), a minority hydrophilic polymer (e.g. polyethylene glycol), and a particle (e.g. a zeolite) with significant affinity and capacity for moisture. During melt compounding, interconnected channels of the hydrophilic polymer are formed that encapsulate chains of particles. The channels are macroscopically percolating, as evidenced by the high moisture uptake of the sample. Confocal fluorescence microscopy is a powerful tool to study the transport and diffusion of a fluorescent dye through the hydrophilic channels as a function of time and particle loading. Our study focuses on the critical particle loading needed for percolation as function of particle type, particle aspect ratio, and relative proportions of hydrophobic and hydrophilic polymers. The results of this study are expected to expand the applications base of this fascinating three-component polymer processing technology.

  18. EDTA-insoluble, calcium-binding proteoglycan in bovine bone

    Science.gov (United States)

    Hashimoto, Y.; Lester, G. E.; Caterson, B.; Yamauchi, M.

    1995-01-01

    A calcium ion precipitable, trypsin-generated proteoglycan fragment has been isolated from the demineralized, EDTA-insoluble matrices of bone. The demineralized matrix was completely digested with trypsin, increasing concentrations of CaCl2 were added to the supernatant, and the resulting precipitates were analyzed. The amount of precipitate gradually increased with higher concentrations of calcium and was reversibly solubilized by EDTA. After molecular sieve and anion exchange chromatography, a proteoglycan-containing peak was obtained. Immunochemical analysis showed that this peak contained chondroitin 4-sulfate and possibly keratan sulfate. Amino acid analysis showed that this proteoglycan contained high amounts of aspartic acid/asparagine (Asx), serine (Ser), glutamic acid/glutamine (Glx), proline (Pro), and glycine (Gly); however, it contained little leucine (Leu) which suggests that it is not a member of the leucine-rich small proteoglycan family. In addition, significant amounts of phosphoserine (P-Ser) and hydroxyproline (Hyp) were identified in hydrolysates of this fraction. A single band (M(r) 59 kDa) was obtained on SDS-PAGE that stained with Stains-all but not with Coomassie Brilliant Blue R-250. If bone powder was trypsinized prior to demineralization, this proteoglycan-containing fraction was not liberated. Collectively, these results indicate that a proteoglycan occurs in the demineralized matrix that is precipitated with CaCl2 and is closely associated with both mineral and collagen matrices. Such a molecule might facilitate the structural network for the induction of mineralization in bone.

  19. Toward an experimental synthesis of the chondritic insoluble organic matter

    Science.gov (United States)

    Biron, Kasia; Derenne, Sylvie; Robert, FrançOis; Rouzaud, Jean-NoëL.

    2015-08-01

    Based on the statistical model proposed for the molecular structure of the insoluble organic matter (IOM) isolated from the Murchison meteorite, it was recently proposed that, in the solar T-Tauri disk regions where (photo)dissociation of gaseous molecules takes place, aromatics result from the cyclization/aromatization of short aliphatics. This hypothesis is tested in this study, with n-alkanes being submitted to high-frequency discharge at low pressure. The contamination issue was eliminated using deuterated precursor. IOM was formed and studied using solid-state nuclear magnetic resonance, pyrolysis coupled to gas chromatography and mass spectrometry, RuO4 oxidation, and high-resolution transmission electron microscopy. It exhibits numerous similarities at the molecular level with the hydrocarbon backbone of the natural IOM, reinforcing the idea that the initial precursors of the IOM were originally chains in the gas. Moreover, a fine comparison between the chemical structure of several meteorite IOM suggests either that (i) the meteorite IOMs share a common precursor standing for the synthetic IOM or that (ii) the slight differences between the meteorite IOMs reflect differences in their environment at the time of their formation i.e., related to plasma temperature that, in turn, dictates the dissociation-recombination rates of organic fragments.

  20. Conversion and Extraction of Insoluble Organic Materials in Meteorites

    Science.gov (United States)

    Locke, Darren R.; Burton, Aaron S.; Niles, Paul B.

    2016-01-01

    We endeavor to develop and implement methods in our laboratory to convert and extract insoluble organic materials (IOM) from low car-bon bearing meteorites (such as ordinary chondrites) and Precambrian terrestrial rocks for the purpose of determining IOM structure and prebiotic chemistries preserved in these types of samples. The general scheme of converting and extracting IOM in samples is summarized in Figure 1. First, powdered samples are solvent extracted in a micro-Soxhlet apparatus multiple times using solvents ranging from non-polar to polar (hexane - non-polar, dichloromethane - non-polar to polar, methanol - polar protic, and acetonitrile - polar aprotic). Second, solid residue from solvent extractions is processed using strong acids, hydrochloric and hydrofluoric, to dissolve minerals and isolate IOM. Third, the isolated IOM is subjected to both thermal (pyrolysis) and chemical (oxidation) degradation to release compounds from the macromolecular material. Finally, products from oxidation and pyrolysis are analyzed by gas chromatography - mass spectrometry (GCMS). We are working toward an integrated method and analysis scheme that will allow us to determine prebiotic chemistries in ordinary chondrites and Precambrian terrestrial rocks. Powerful techniques that we are including are stepwise, flash, and gradual pyrolysis and ruthenium tetroxide oxidation. More details of the integrated scheme will be presented.

  1. EDTA-insoluble, calcium-binding proteoglycan in bovine bone.

    Science.gov (United States)

    Hashimoto, Y; Lester, G E; Caterson, B; Yamauchi, M

    1995-05-01

    A calcium ion precipitable, trypsin-generated proteoglycan fragment has been isolated from the demineralized, EDTA-insoluble matrices of bone. The demineralized matrix was completely digested with trypsin, increasing concentrations of CaCl2 were added to the supernatant, and the resulting precipitates were analyzed. The amount of precipitate gradually increased with higher concentrations of calcium and was reversibly solubilized by EDTA. After molecular sieve and anion exchange chromatography, a proteoglycan-containing peak was obtained. Immunochemical analysis showed that this peak contained chondroitin 4-sulfate and possibly keratan sulfate. Amino acid analysis showed that this proteoglycan contained high amounts of aspartic acid/asparagine (Asx), serine (Ser), glutamic acid/glutamine (Glx), proline (Pro), and glycine (Gly); however, it contained little leucine (Leu) which suggests that it is not a member of the leucine-rich small proteoglycan family. In addition, significant amounts of phosphoserine (P-Ser) and hydroxyproline (Hyp) were identified in hydrolysates of this fraction. A single band (M(r) 59 kDa) was obtained on SDS-PAGE that stained with Stains-all but not with Coomassie Brilliant Blue R-250. If bone powder was trypsinized prior to demineralization, this proteoglycan-containing fraction was not liberated. Collectively, these results indicate that a proteoglycan occurs in the demineralized matrix that is precipitated with CaCl2 and is closely associated with both mineral and collagen matrices. Such a molecule might facilitate the structural network for the induction of mineralization in bone.

  2. Calcium digestibility studies utilizing acid-insoluble ash measurements.

    Science.gov (United States)

    Cheng, T K; Coon, C N

    1990-12-01

    Laying hens were individually fed diets providing daily calcium intakes ranging from 2.0 to 4.5 g from two sources of limestone. Silica (washed sand) was added to the diets as filler for hens with less than 4.5 g of daily calcium intake. The calcium digestibility data were obtained both by the total collection (TC) method and b y using acid-insoluble ash (AIA) as an indicator. Source effect was not significant (P greater than .7) within each method tested, and data were pooled for analysis. The calcium digestibility values obtained by the TC method for hens with intake of 2.0, 2.5, 3.0, 3.5, 4.0, and 4.5 g daily were 59.16, 57.31, 54.29, 50.99, 44.63, and 41.76%, respectively. The AIA method consistently yielded higher digestibility values: 73.0, 65.36, 61.78, 54.19, 45.76, and 42.0%. The differences in calcium digestibility values between the two methods were linearly related to the levels of silica consumption (P less than .05).

  3. Determination of insoluble, soluble, and total dietary fiber (CODEX definition) by enzymatic-gravimetric method and liquid chromatography: collaborative study.

    Science.gov (United States)

    McCleary, Barry V; DeVries, Jonathan W; Rader, Jeanne I; Cohen, Gerald; Prosky, Leon; Mugford, David C; Okuma, Kazuhiro

    2012-01-01

    A method for the determination of insoluble (IDF), soluble (SDF), and total dietary fiber (TDF), as defined by the CODEX Alimentarius, was validated in foods. Based upon the principles of AOAC Official Methods 985.29, 991.43, 2001.03, and 2002.02, the method quantitates water-insoluble and water-soluble dietary fiber. This method extends the capabilities of the previously adopted AOAC Official Method 2009.01, Total Dietary Fiber in Foods, Enzymatic-Gravimetric-Liquid Chromatographic Method, applicable to plant material, foods, and food ingredients consistent with CODEX Definition 2009, including naturally occurring, isolated, modified, and synthetic polymers meeting that definition. The method was evaluated through an AOAC/AACC collaborative study. Twenty-two laboratories participated, with 19 laboratories returning valid assay data for 16 test portions (eight blind duplicates) consisting of samples with a range of traditional dietary fiber, resistant starch, and nondigestible oligosaccharides. The dietary fiber content of the eight test pairs ranged from 10.45 to 29.90%. Digestion of samples under the conditions of AOAC 2002.02 followed by the isolation, fractionation, and gravimetric procedures of AOAC 985.29 (and its extensions 991.42 and 993.19) and 991.43 results in quantitation of IDF and soluble dietary fiber that precipitates (SDFP). The filtrate from the quantitation of water-alcohol-insoluble dietary fiber is concentrated, deionized, concentrated again, and analyzed by LC to determine the SDF that remains soluble (SDFS), i.e., all dietary fiber polymers of degree of polymerization = 3 and higher, consisting primarily, but not exclusively, of oligosaccharides. SDF is calculated as the sum of SDFP and SDFS. TDF is calculated as the sum of IDF and SDF. The within-laboratory variability, repeatability SD (Sr), for IDF ranged from 0.13 to 0.71, and the between-laboratory variability, reproducibility SD (SR), for IDF ranged from 0.42 to 2.24. The within

  4. Thermoresponsive Polymers for Nuclear Medicine: Which Polymer Is the Best?

    Science.gov (United States)

    Sedláček, Ondřej; Černoch, Peter; Kučka, Jan; Konefal, Rafał; Štěpánek, Petr; Vetrík, Miroslav; Lodge, Timothy P; Hrubý, Martin

    2016-06-21

    Thermoresponsive polymers showing cloud point temperatures (CPT) in aqueous solutions are very promising for the construction of various systems in biomedical field. In many of these applications these polymers get in contact with ionizing radiation, e.g., if they are used as carriers for radiopharmaceuticals or during radiation sterilization. Despite this fact, radiosensitivity of these polymers is largely overlooked to date. In this work, we describe the effect of electron beam ionizing radiation on the physicochemical and phase separation properties of selected thermoresponsive polymers with CPT between room and body temperature. Stability of the polymers to radiation (doses 0-20 kGy) in aqueous solutions increased in the order poly(N-vinylcaprolactam) (PVCL, the least stable) ≪ poly[N-(2,2-difluoroethyl)acrylamide] (DFP) radiation (1 kGy), which are highly relevant to the storage of polymer radiotherapeutics and sterilization of biomedical systems, cause significant increase in molecular weight due to cross-linking (except for POX, where this effect is weak). In the case of PVCL irradiated with low doses, the increase in molecular weight induced an increase in the CPT of the polymer. For PNIPAM and DFP, there is strong chain hydrophilization leading to an increase in CPT. From this perspective, POX is the most suitable polymer for the construction of delivery systems that experience exposure to radiation, while PVCL is the least suitable and PNIPAM and DFP are suitable only for low radiation demands.

  5. Coating solid dispersions on microneedles via a molten dip coating method: development and in vitro evaluation for transdermal delivery of a water insoluble drug

    Science.gov (United States)

    Ma, Yunzhe; Gill, Harvinder S.

    2014-01-01

    This study demonstrates for the first time the ability to coat solid dispersions on microneedles as a means to deliver water-insoluble drugs through the skin. Polyethylene glycol (PEG) was selected as the hydrophilic matrix, and lidocaine base was selected as the model hydrophobic drug to create the solid dispersion. First, thermal characterization and viscosity measurements of the PEG-lidocaine mixture at different mass fractions were performed. The results show that lidocaine can remain stable at temperatures up to ~130 °C, and that viscosity of the PEG-lidocaine molten solution increases as the mass fraction of lidocaine decreases. Differential scanning calorimetry demonstrated that at lidocaine mass fraction less than or equal to 50%, lidocaine is well dispersed in the PEG-lidocaine mixture. Uniform coatings were obtained on microneedle surfaces. In vitro dissolution studies in porcine skin showed that microneedles coated with PEG-lidocaine dispersions resulted in significantly higher delivery of lidocaine in just 3 min compared to 1 h topical application of 0.15 g EMLA®, a commercial lidocaine-prilocaine cream. In conclusion, the molten coating process we introduce here offers a practical approach to coat water-insoluble drugs on microneedles for transdermal delivery. PMID:25213295

  6. Porous polymer networks: synthesis, porosity, and applications in gas storage/separation

    NARCIS (Netherlands)

    Lu, W.; Yuan, D.; Zhao, D.; Schilling, C.I.; Plietzsch, O.; Muller, T.; Bräse, S.; Guenther, J.; Blümel, J.; Krishna, R.; Li, Z.; Zhou, H.C.

    2010-01-01

    Three porous polymer networks (PPNs) have been synthesized by the homocoupling of tetrahedral monomers. Like other hyper-cross-linked polymer networks, these materials are insoluble in conventional solvents and exhibit high thermal and chemical stability. Their porosity was confirmed by N2 sorption

  7. Photocrosslinking of ferroelectric polymers and its application in three-dimensional memory arrays

    NARCIS (Netherlands)

    van Breemen, A. J. J. M.; van der Putten, J. B. P. H.; Cai, R.; Reimann, K.; Marsman, A. W.; Willard, N.; de Leeuw, D. M.; Gelinck, G. H.

    2011-01-01

    An I-line photolithography process for ferroelectric polymers is developed. It is based on photocrosslinking using a bisazide photoinitiator. Patterned layers were realized down to 1-2 mu m resolution. Crosslinking yields a close-to-insoluble ferroelectric polymer network that counter intuitively

  8. Study of polymer dispersed liquid crystal film based on amphiphilic polymer matrix

    OpenAIRE

    Ahmad, Farzana; Jamil, Muhammad; Jeon, Young Jae

    2014-01-01

    Polymer dispersed liquid crystal (PDLC) films’ morphologies and electro-optical properties have been mostly investigated on the method of polymerization, rate of reaction, the relative amount, characteristic, and temperature of the LC/monomer mixtures; in chorus with the molecular associations existing among the LC, monomer molecules and with the glass. In this effort the molecular associations of polymer matrix having hydrophilic and hydrophobic characteristics are considered with the LC. He...

  9. Capillary instability on a hydrophilic stripe

    Science.gov (United States)

    Speth, Raymond L.; Lauga, Eric

    2009-07-01

    A recent experiment showed that cylindrical segments of water filling a hydrophilic stripe on an otherwise hydrophobic surface display a capillary instability when their volume is increased beyond the critical volume at which their apparent contact angle on the surface reaches 90° (Gau et al 1999 Science 283 46-9). Surprisingly, the fluid segments did not break up into droplets—as would be expected for a classical Rayleigh-Plateau instability—but instead displayed a long-wavelength instability where all excess fluid gathered in a single bulge along each stripe. We consider here the dynamics of the flow instability associated with this setup. We perform a linear stability analysis of the capillary flow problem in the inviscid limit. We first confirm previous work showing that all cylindrical segments are linearly unstable if (and only if) their apparent contact angle is larger than 90°. We then demonstrate that the most unstable wavenumber for the surface perturbation decreases to zero as the apparent contact angle of the fluid on the surface approaches 90°, allowing us to re-interpret the creation of bulges in the experiment as a zero-wavenumber capillary instability. A variation of the stability calculation is also considered for the case of a hydrophilic stripe located on a wedge-like geometry.

  10. Capillary instability on a hydrophilic stripe

    Energy Technology Data Exchange (ETDEWEB)

    Speth, Raymond L [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Lauga, Eric [Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0411 (United States)], E-mail: elauga@ucsd.edu

    2009-07-15

    A recent experiment showed that cylindrical segments of water filling a hydrophilic stripe on an otherwise hydrophobic surface display a capillary instability when their volume is increased beyond the critical volume at which their apparent contact angle on the surface reaches 90 deg. (Gau et al 1999 Science 283 46-9). Surprisingly, the fluid segments did not break up into droplets-as would be expected for a classical Rayleigh-Plateau instability-but instead displayed a long-wavelength instability where all excess fluid gathered in a single bulge along each stripe. We consider here the dynamics of the flow instability associated with this setup. We perform a linear stability analysis of the capillary flow problem in the inviscid limit. We first confirm previous work showing that all cylindrical segments are linearly unstable if (and only if) their apparent contact angle is larger than 90 deg. We then demonstrate that the most unstable wavenumber for the surface perturbation decreases to zero as the apparent contact angle of the fluid on the surface approaches 90 deg, allowing us to re-interpret the creation of bulges in the experiment as a zero-wavenumber capillary instability. A variation of the stability calculation is also considered for the case of a hydrophilic stripe located on a wedge-like geometry.

  11. Insoluble nonstarch polysaccharides in diets for weaned piglets.

    Science.gov (United States)

    Gerritsen, R; van der Aar, P; Molist, F

    2012-12-01

    To examine the effect of inclusion insoluble nonstarch polysaccharides (iNSP) in weaned diets on postweaning piglet performance, intestinal activity, and microbial composition 2 experiments were designed. In Exp. 1, 180 piglets were weaned at 28 d of age and divided over 3 treatments: positive control (PC; highly digestible protein), negative control (NC; standard cereal-based diet), and an experimental diet {iNSP; standard + 15% iNSP [wheat straw and oat (Avena sativa) hull]}. Diets were fed during 14 d after weaning. The ADFI, ADG, and G:F were determined. The inclusion of iNSP increased (P weaning and increased the ADG (P = 0.008) during days 0 to 7 after weaning compared with the NC diet. In Exp. 2, 36 piglets were fed the same diets as in Exp. 1. On days 5 and 14 after weaning, 18 piglets were euthanized to determine enzyme activity, intestinal morphology, and microbial population in the ileum and colon and organ weight. The iNSP diet reduced the concentration of Escherichia coli bacteria in the ileum (P = 0.021) and in the colon (P = 0.002) digesta and tended to increase (P = 0.060) the amylase activity. The iNSP diet stimulated the physical adaptation of the gastrointestinal tract because stomach weight as percentage of BW was heavier (P = 0.004) than for the NC diet. In conclusion, the consumption of diets with higher iNSP content in the early weaning period affects the microbial colonization without reducing enzyme activity or animal performance compared with a standard weaned pig diet.

  12. Unusual Transformation from a Solvent-Stabilized 1D Coordination Polymer to a Metal-Organic Framework (MOF)-Like Cross-Linked 3D Coordination Polymer.

    Science.gov (United States)

    Lee, Seung-Chul; Choi, Eun-Young; Lee, Sang-Beom; Kim, Sang-Wook; Kwon, O-Pil

    2015-10-26

    An unusual 1D-to-3D transformation of a coordination polymer based on organic linkers containing highly polar push-pull π-conjugated side chains is reported. The coordination polymers are synthesized from zinc nitrate and an organic linker, namely, 2,5-bis{4-[1-(4-nitrophenyl)pyrrolidin-2-yl]butoxy}terephthalic acid, which possesses highly polar (4-nitrophenyl)pyrrolidine groups, with high dipole moments of about 7 D. The coordination polymers exhibit an unusual transformation from a soluble, solvent-stabilized 1D coordination polymer into an insoluble, metal-organic framework (MOF)-like 3D coordination polymer. The coordination polymer exhibits good film-forming ability, and the MOF-like films are insoluble in conventional organic solvents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. In vitro evaluation of iris chafe protection afforded by hydrophilic surface modification of polymethylmethacrylate intraocular lenses.

    Science.gov (United States)

    Hofmeister, F M; Yalon, M S; Iida, S; Goldberg, M D

    1988-09-01

    An in vitro iris chafe test was developed to evaluate possible differences in abrasive interaction of various intraocular lens (IOL) materials with the posterior surface of the iris. The materials that were compared in initial tests with rabbit irides were high molecular weight polymethylmethacrylate (PMMA), the primary IOL material in current use, and surface-modified PMMA, which had a permanent, chemically bound, hydrophilic, polymer surface. Scanning electron microscopy, light microscopy, and examination of histological sections were used to assess tissue damage. A "window defect" type of abrasive damage was observed by light microscopy for PMMA lenses and is very similar in appearance to that seen for iris abrasion by human implants when viewed in vivo in slitlamp examinations. Results for both pigmented and albino rabbit irides indicate a reduction in abrasive insult to the external iris basement membrane and underlying pigment epithelium by the hydrophilic surface modification of PMMA. These results are consistent with our observation of a major reduction in corneal endothelium damage on contact with the hydrophilic surface-modified PMMA as compared with PMMA itself. This in vitro iris abrasion test, therefore, appears to be a useful technique for future evaluation of IOL surface properties.

  14. Comparison of the Fouling Release Properties of Hydrophobic Fluorinated and Hydrophilic PEGylated Block Copolymer Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan,S.; Wang, N.; Ober, C.; Finlay, J.; Callow, M.; Callow, J.; Hexemer, A.; Sohn, K.; Kramer, E.; Fischer, D.

    2006-01-01

    To understand the role of surface wettability in adhesion of cells, the attachment of two different marine algae was studied on hydrophobic and hydrophilic polymer surfaces. Adhesion of cells of the diatom Navicula and sporelings (young plants) of the green macroalga Ulva to an underwater surface is mainly by interactions between the surface and the adhesive exopolymers, which the cells secrete upon settlement and during subsequent colonization and growth. Two types of block copolymers, one with poly(ethylene glycol) side-chains and the other with liquid crystalline, fluorinated side-chains, were used to prepare the hydrophilic and hydrophobic surfaces, respectively. The formation of a liquid crystalline smectic phase in the latter inhibited molecular reorganization at the surface, which is generally an issue when a highly hydrophobic surface is in contact with water. The adhesion strength was assessed by the fraction of settled cells (Navicula) or biomass (Ulva) that detached from the surface in a water flow channel with a wall shear stress of 53 Pa. The two species exhibited opposite adhesion behavior on the same sets of surfaces. While Navicula cells released more easily from hydrophilic surfaces, Ulva sporelings showed higher removal from hydrophobic surfaces. This highlights the importance of differences in cell-surface interactions in determining the strength of adhesion of cells to substrates.

  15. 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 highe...... 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....

  16. Soluble antioxidant compounds regenerate the antioxidants bound to insoluble parts of foods.

    Science.gov (United States)

    Çelik, Ecem Evrim; Gökmen, Vural; Fogliano, Vincenzo

    2013-10-30

    This study aimed to investigate the regeneration potential of antioxidant capacity of an insoluble food matrix. Investigations were performed in vitro with several food matrices rich in dietary fiber (DF) and bound antioxidants. After removal of the soluble fraction, the antioxidant capacity (AC) of the insoluble fraction was measured by the QUENCHER procedure using ABTS(•+) or DPPH(•) radicals. After measurement, the insoluble residue was washed out to remove the excess of radicals and treated with pure antioxidant solution or antioxidant-rich beverage to regenerate depleted antioxidants on the fiber. Results revealed that the antioxidant capacity of compounds chemically bound to the insoluble moiety could be reconstituted in the presence of other hydrogen-donating substances in the liquid phase. Regeneration efficiency was found to range between 21.5 and 154.3% depending on the type of insoluble food matrix and regeneration agent. Among the food matrices studied, cereal products were found to have slightly higher regeneration efficiency, whereas antioxidant-rich beverages were more effective than pure antioxidants as regeneration agents. Taking wheat bran as reference insoluble material, the regeneration abilities of beverages were in the following order: green tea > espresso coffee > black tea > instant coffee > orange juice > red wine. These results highlighted the possible physiological relevance of antioxidants bound to the insoluble food material in the gastrointestinal tract. During the digestion process they could react with the free radicals and at the same time they can be regenerated by other soluble antioxidant compounds present in the meal.

  17. π-Conjugate Fluorophore-Tagged and Enzyme-Responsive l-Amino Acid Polymer Nanocarrier and Their Color-Tunable Intracellular FRET Probe in Cancer Cells.

    Science.gov (United States)

    Saxena, Sonashree; Jayakannan, Manickam

    2017-08-14

    The present investigation accounts one of the first example of enzyme-responsive and π-conjugate-tagged l-amino acid amphiphilic polymer and their fluorescence resonance energy transfer (FRET) probes for color-tunable intracellular bioimaging in cancer cells. Melt polymerizable oligo-phenylenevinylene (OPV) π-conjugated diol was tailor-made and subjected to thermo-selective melt transesterification reaction with multifunctional l-aspartic acid monomer to yield OPV-tagged amphiphilic luminescent polyesters. These amphiphilic polyesters self-assembled through strong aromatic π-π stacking and hydrophilic/hydrophobic noncovalent forces into FRET donor and encapsulated water insoluble Nile Red (NR) fluorophore as a FRET acceptor. Detail photophysical studies revealed that both the OPV and NR were confined within Förster distance in the polymer nanocontainer and the nanodomains provided appropriate geometry for efficient excitation energy transfer from OPV to NR. Cytotoxicity studies in breast cancer (MCF 7), cervical cancer (HeLa) and normal (Wild-type MEF) cell lines revealed that both the nascent luminescent OPV nanoparticles and OPV-NR FRET probes were nontoxic to cells up to 100 μg/mL. Confocal microscope images confirmed the efficient transportation of polymer and FRET probes across the cell membranes and their preferable accumulation in the cytoplasm of the cells. Lysosomal tracker assisted live cell imaging provided direct evidence for the localization of the polymer nanoparticles at the lysosomal compartments in the cytoplasm. In vitro enzyme-responsive studies revealed that the aliphatic polyester backbone in the polymer nanoparticles was readily biodegradable by lysosomal enzymes like esterase, chymotrypsin, trypsin, and also redox GSH species in the cytoplasm. Selective photoexcitation in confocal microscope exhibited bright OPV blue-luminescence and strong red-emission from NR followed by the excitation energy transfer and occurrence of FRET process at

  18. Hydroxylamine hydrochloride-acetic acid-soluble and -insoluble fractions of pelagic sediment: Readsorption revisited

    Science.gov (United States)

    Piper, D.Z.; Wandless, G.A.

    1992-01-01

    The extraction of the rare earth elements (REE) from deep-ocean pelagic sediment, using hydroxylamine hydrochloride-acetic acid, leads to the separation of approximately 70% of the bulk REE content into the soluble fraction and 30% into the insoluble fraction. The REE pattern of the soluble fraction, i.e., the content of REE normalized to average shale on an element-by-element basis and plotted against atomic number, resembles the pattern for seawater, whereas the pattern, as well as the absolute concentrations, in the insoluble fraction resembles the North American shale composite. These results preclude significant readsorption of the REE by the insoluble phases during the leaching procedure.

  19. Permanent hydrophilic modification of polypropylene and poly(vinyl alcohol) films by vacuum ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Belmonte, Guilherme Kretzmann [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Charles, German [Centro de Química Aplicada (CEQUIMAP), Facultad de Ciencias Químicas, Unversidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba 5000 (Argentina); Strumia, Miriam Cristina [Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, IPQA-Conicet, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba 5000 (Argentina); Weibel, Daniel Eduardo, E-mail: danielw@iq.ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil)

    2016-09-30

    Highlights: • Polypropylene and Poly(vinyl alcohol) were surface modified by vacuum ultraviolet (VUV) irradiation. • The hydrophilicity of the treated films was permanent and resisted aging for several months. • Grafting of styrene monomer was only observed in the VUV irradiated regions. • The obtained results showed the potential in the use of VUV treatment for surface modification and processing of polymers which lack chromophores in the UV region. - Abstract: Polypropylene (PP) and Poly(vinyl alcohol) (PVA) both synthetics polymers but one of them biodegradable, were surface modified by vacuum ultraviolet (VUV) irradiation. After VUV irradiation in an inert nitrogen atmosphere, the films were exposed to oxygen gas. The treated films were characterized by water contact angle measurements (WCA), optical profilometry, FTIR-ATR, XPS, UPS and NEXAFS techniques. PP and PVA VUV-treated films reached superhydrophilic conditions (WCAs <10°) in about 30 min of irradiation under our experimental conditions. It was observed that when the WCAs reached about 35–40° the hydrophilicity was permanent in both polymers. These results contrasted with typical plasma treatments were a rapid hydrophobic recovery with aging time is usually observed. UPS and XPS data showed the presence of new functionalities on the PP and PVA surfaces that were assigned to COO, C=O, C−O and C=C functional groups. Finally, grafting of styrene (ST) as a typical monomer was tested on PP films. It was confirmed that only in the VUV irradiated region an efficient grafting of ST or polymerized ST was found. Outside the irradiated regions no ST grafted was observed. Our results showed the potential use of VUV treatment for surface modification and processing of polymers which lack chromophores in the UV region.

  20. Controlling the hydrophilicity and contact resistance of fuel cell bipolar plate surfaces using layered nanoparticle assembly

    Science.gov (United States)

    Wang, Feng

    Hybrid nanostructured coatings exhibiting the combined properties of electrical conductivity and surface hydrophilicity were obtained by using Layer-by-Layer (LBL) assembly of cationic polymer, silica nanospheres, and carbon nanoplatelets. This work demonstrates that by controlling the nanoparticle zeta (zeta) potential through the suspension parameters (pH, organic solvent type and amount, and ionic content) as well as the assembly sequence, the nanostructure and composition of the coatings may be adjusted to optimize the desired properties. Two types of silica nanospheres were evaluated as the hydrophilic component: X-TecRTM 3408 from Nano-X Corporation, with a diameter of about 20 nm, and polishing silica from Electron Microscopy Supply, with diameter of about 65 nm. Graphite nanoplatelets with a thickness of 5~10nm (Aquadag RTM E from Acheson Industries) were used as electrically conductive filler. A cationic copolymer of acrylamide and a quaternary ammonium salt (SuperflocRTM C442 from Cytec Corporation) was used as the binder for the negatively charged nanoparticles. Coatings were applied to gold-coated stainless steel substrates presently used a bipolar plate material for proton exchange membrane (PEM) fuel cells. Coating thickness was found to vary nearly linearly with the number of polymer-nanoparticle layers deposited while a monotonic increase in coating contact resistance was observed for all heterogeneous and pure silica coatings. Thickness increased if the difference in the oppositely charged zeta potentials of the adsorbing components was enhanced through alcohol addition. Interestingly, an opposite effect was observed if the zeta potential difference was increased through pH variation. This previously undocumented difference in adsorption behavior is herein related to changes to the surface chemical heterogeneity of the nanoparticles. Coating contact resistance and surface wettability were found to have a more subtle dependence on the assembly

  1. Design and Fabrication of a Hybrid Superhydrophobic-Hydrophilic Surface That Exhibits Stable Dropwise Condensation.

    Science.gov (United States)

    Mondal, Bikash; Mac Giolla Eain, Marc; Xu, QianFeng; Egan, Vanessa M; Punch, Jeff; Lyons, Alan M

    2015-10-28

    Condensation of water vapor is an essential process in power generation, water collection, and thermal management. Dropwise condensation, where condensed droplets are removed from the surface before coalescing into a film, has been shown to increase the heat transfer efficiency and water collection ability of many surfaces. Numerous efforts have been made to create surfaces which can promote dropwise condensation, including superhydrophobic surfaces on which water droplets are highly mobile. However, the challenge with using such surfaces in condensing environments is that hydrophobic coatings can degrade and/or water droplets on superhydrophobic surfaces transition from the mobile Cassie to the wetted Wenzel state over time and condensation shifts to a less-effective filmwise mechanism. To meet the need for a heat-transfer surface that can maintain stable dropwise condensation, we designed and fabricated a hybrid superhydrophobic-hydrophilic surface. An array of hydrophilic needles, thermally connected to a heat sink, was forced through a robust superhydrophobic polymer film. Condensation occurs preferentially on the needle surface due to differences in wettability and temperature. As the droplet grows, the liquid drop on the needle remains in the Cassie state and does not wet the underlying superhydrophobic surface. The water collection rate on this surface was studied using different surface tilt angles, needle array pitch values, and needle heights. Water condensation rates on the hybrid surface were shown to be 4 times greater than for a planar copper surface and twice as large for silanized silicon or superhydrophobic surfaces without hydrophilic features. A convection-conduction heat transfer model was developed; predicted water condensation rates were in good agreement with experimental observations. This type of hybrid superhydrophobic-hydrophilic surface with a larger array of needles is low-cost, robust, and scalable and so could be used for heat

  2. [The hydrophilicity and cell affinity of polylactic acid containg bionic function group of phosphorylcholine].

    Science.gov (United States)

    Luo, Juan; Wang, Lijian; Chen, Yuanwei; Luo, Xianglin; Chen, Nianchao; Wan, Changxiu; Zhang, Xiaohua

    2008-12-01

    A series of novel biodegradable and bionic functional polymers, PLLA-PC-PLLA, were synthesized using L-lactide ring-opening polymerization by L-a-Glycerophosphorylcholine (PC) from nature source. The hydrophilicity of the polymers was investigated. The results made known that, as PC group was brought into the backbone of PLLA, PLLA-PC-PLLA gained much better hydrophilicity than did PLLA, and polar phosphatidylcholines probably transferred to the sample surface in aqueous environment. The relative growth ratios of ECV304 cells to the lixivium of all PLLA-PC-PLLA were higher than 84% in 5 d culture. The cells adhesion of ECV304 on the films of PLLA-PC-PLLA lagged as compared to that on PLLA, but they could proliferate and cover the films in total. The difference between PLLA-PC-PLLA and PLLA was due to the existence of PC group. Thus, PLLA-PC-PLLA, the same as PLLA, are not cytotoxic, and ECV304 can attach and proliferate on them. PLLA-PC-PLLA have potential applications in the fields of tissue engineering and drug delivery system.

  3. Hydrophilic monolayer formation of adsorbed cationic starch and cationic hydroxyethyl cellulose derivatives on polyester surfaces.

    Science.gov (United States)

    Roos, Peter; Westling, Asa; Chronakis, Ioannis S

    2004-11-01

    Cationic starch, cationic cellulose derivatives, and hydrophobically modified cationic cellulose were physically adsorbed from aqueous solution onto oppositely charged hydrophobic polyester (poly(ethylene terephthalate)) fabric and nonwoven, and this resulted in hydrophilic surface properties. Surface coverage of the polysaccharides occurred primarily by strong electrostatic interactions, and the surface characteristics were evaluated by measuring the time required for a water droplet to be absorbed into the polyester material as well as by electron spectroscopy for chemical analysis (ESCA). From a comparison of the adsorption characteristics we assess the polysaccharide-dependent and substrate-dependent adsorption behavior and discuss the similarities and differences in the hydrophilic properties and wettability observed. In particular, the temperature of the cationic polysaccharide solutions in which the substrate was immersed, the configuration of the polymer in solution, and the presence of hydrophobic substituents on the cationic moiety have a considerable effect on the polysaccharide affinity and its adsorption on the surface, irrespective of the substrate type (fabric or nonwoven). We also evaluate the relative contribution of the polyelectrolyte molecular weight, concentration in solution, and degree of charge density along the polymer chain which determine the range of interactions and alter surface hydroplilicity dependent on the type of substrate.

  4. Flocculating and dewatering performance of hydrophobic and hydrophilic solids using a thermal-sensitive copolymer.

    Science.gov (United States)

    Li, Shulei; Liao, Yinfei; Li, Guosheng; Li, Zhen; Cao, Yijun

    2017-07-01

    Thermal-sensitive polymers have been tested on settling, compacting or dewatering of clays or oil sand tailings. However, not much attention has been paid to explore the effect of temperature on flocculating performance using thermal-sensitive polymers. In this study, poly(NIPAM-co-DMAPMA) was synthesized and employed to investigate the flocculating and re-flocculating performance of hydrophilic and hydrophobic particles at two specific temperatures; meanwhile settling and dewatering behaviors were also investigated. The results demonstrated that good flocculating performances were achieved at both room temperature (∼23 °C) and lower critical solution temperature (45 °C). Furthermore, larger flocs were formed at 45 °C as the copolymer was added. Floc strength and re-flocculating ability of the flocs were also intensified prominently at 45 °C. Additionally, settling and dewatering rates of suspensions were improved, and the moisture of filtered cakes was reduced when suspensions were at 45 °C. The phenomena could be justified by the phase transition of the copolymer from hydrophilicity to hydrophobicity as the temperature increased. There were much stronger adhesion forces between particles and higher adsorption amount of the copolymer onto solid surfaces at 45 °C. Therefore, the copolymer may be promising in solid-liquid separation to improve the floc size, floc strength, and settling and dewatering rate to achieve much lower moisture filtered cake.

  5. Hydrophilic crosslinked-polymeric surface capable of effective suppression of protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Kamon, Yuri; Inoue, Naoko; Mihara, Erika; Kitayama, Yukiya; Ooya, Tooru; Takeuchi, Toshifumi, E-mail: takeuchi@gold.kobe-u.ac.jp

    2016-08-15

    Highlights: • Three hydrophilic crosslinked polymers were examined for protein adsorption. • All polymers showed low nonspecific adsorption of negatively charged proteins. • Poly(MMPC) showed the lowest adsorption for positively charged proteins. • Poly(MMPC) is able to reduce nonspecific adsorption of a wide range of proteins. - Abstract: We investigated the nonspecific adsorption of proteins towards three hydrophilic crosslinked-polymeric thin layers prepared by surface-initiated atom transfer radical polymerization using N,N′-methylenebisacrylamide, 2-(methacryloyloxy)ethyl-[N-(2-methacryloyloxy)ethyl]phosphorylcholine (MMPC), or 6,6′-diacryloyl-trehalose crosslinkers. Protein binding experiments were performed by surface plasmon resonance with six proteins of different pI values including α-lactalbumin, bovine serum albumin (BSA), myoglobin, ribonuclease A, cytochrome C, and lysozyme in buffer solution at pH 7.4. All of the obtained crosslinked-polymeric thin layers showed low nonspecific adsorption of negatively charged proteins at pH 7.4 such as α-lactalbumin, BSA, and myoglobin. Nonspecific adsorption of positively charged proteins including ribonuclease A, cytochrome C, and lysozyme was the lowest for poly(MMPC). These results suggest poly(MMPC) can effectively reduce nonspecific adsorption of a wide range of proteins that are negatively or positively charged at pH 7.4. MMPC is a promising crosslinker for a wide range of polymeric materials requiring low nonspecific protein binding.

  6. Hydrophilic excipients modulate the time lag of time-controlled disintegrating press-coated tablets.

    Science.gov (United States)

    Lin, Shan-Yang; Li, Mei-Jane; Lin, Kung-Hsu

    2004-08-16

    An oral press-coated tablet was developed by means of direct compression to achieve the time-controlled disintegrating or rupturing function with a distinct predetermined lag time. This press-coated tablet containing sodium diclofenac in the inner core was formulated with an outer shell by different weight ratios of hydrophobic polymer of micronized ethylcellulose (EC) powder and hydrophilic excipients such as spray-dried lactose (SDL) or hydroxypropyl methylcellulose (HPMC). The effect of the formulation of an outer shell comprising both hydrophobic polymer and hydrophilic excipients on the time lag of drug release was investigated. The release profile of the press-coated tablet exhibited a time period without drug release (time lag) followed by a rapid and complete release phase, in which the outer shell ruptured or broke into 2 halves. The lag phase was markedly dependent on the weight ratios of EC/SDL or EC/HPMC in the outer shell. Different time lags of the press-coated tablets from 1.0 to 16.3 hours could be modulated by changing the type and amount of the excipients. A semilogarithmic plot of the time lag of the tablet against the weight ratios of EC/SDL or EC/HPMC in the outer shell demonstrated a good linear relationship, with r = 0.976 and r = 0.982, respectively. The predetermined time lag prior to the drug release from a press-coated tablet prepared by using a micronized EC as a retarding coating shell can be adequately scheduled with the addition of hydrophilic excipients according to the time or site requirements.

  7. Decreasing Particle Size of Paclitaxel Using Polymer in Fractional Precipitation Process

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Jae; Kim, Jin-Hyun [Kongju National University, Cheonan (Korea, Republic of)

    2016-04-15

    In this study, we have for the first time applied fractional precipitation with hydrophilic polymer in order to decrease the particle size of the anticancer agent paclitaxel from plant cell cultures. When compared with the case where no hydrophilic polymer was employed, the addition of hydrophilic polymer in fractional precipitation resulted in a decrease in the size of the paclitaxel precipitate. Among the polymers used, HPMC 2910 was the most effective for inhibition of precipitate growth. A polymer concentration of 0.2% (w/v) obtained the smallest particle size. The particle size was reduced by -35% compared to control. In addition, the precipitate size was inversely correlated with the absolute value of the zeta potential.

  8. Biodegradable Polymers

    OpenAIRE

    Isabelle Vroman; Lan Tighzert

    2013-01-01

    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. ...

  9. Involvement of detergent-insoluble complexes in the intracellular transport of intestinal brush border enzymes

    DEFF Research Database (Denmark)

    Danielsen, E M

    1995-01-01

    A number of transmembrane digestive enzymes of the porcine small intestinal brush border membrane were found to be partially Triton X-100-insoluble at 0 degree C and colocalized in gradient centrifugation experiments with the GPI-anchored alkaline phosphatase in low-density, detergent......%), and lactase-phlorizin hydrolase (EC 3.2.1.23-62) was essentially fully soluble in detergent. In radioactively labeled, mucosal explants, the newly synthesized brush border enzymes began to associate with detergent-insoluble complexes while still in their transient, high mannose-glycosylated form......, and their insolubility increased to that of the steady-state level soon after they achieved their mature, complex glycosylation, i.e., after passage through the Golgi complex. Detergent-insoluble complexes isolated by density gradient centrifugation were highly enriched in brush border enzymes, and the enrichment...

  10. Recent applications of hydrophilic interaction liquid chromatography in pharmaceutical analysis.

    Science.gov (United States)

    Zhang, Qian; Yang, Feng-Qing; Ge, Liya; Hu, Yuan-Jia; Xia, Zhi-Ning

    2017-01-01

    Hydrophilic interaction liquid chromatography, an alternative liquid chromatography mode, is of particular interest in separating hydrophilic and polar ionic compounds. Compared with traditional liquid chromatography techniques, hydrophilic interaction liquid chromatography offers specific advantages mainly including: (1) relatively green and water-soluble mobile phase composition, which enhances the solubility of hydrophilic and polar ionic compounds; (2) no need for ion-pairing reagents and high content of organic solvent, which benefits mass spectrometry detection; (3) high orthogonality to reverse-phase liquid chromatography, well adapted to two-dimensional liquid chromatography for complicated samples. Therefore, hydrophilic interaction liquid chromatography has been rapidly developed in many areas over the past decades. This review summarizes the recent progress (from 2012 to July 2016) of hydrophilic interaction liquid chromatography in pharmaceutical analysis, with the focus on detecting chemical drugs in various matrices, charactering active compounds of natural products and assessing biotherapeutics through typical structure unit. Moreover, the retention mechanism and behavior of analytes in hydrophilic interaction liquid chromatography as well as some novel hydrophilic interaction liquid chromatography columns used for pharmaceutical analysis are also described. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Effects of Toasting Time on Digestive Hydrolysis of Soluble and Insoluble 00-Rapeseed Meal Proteins

    OpenAIRE

    Salazar-Villanea, Sergio; Bruininx, Erik M.A.M.; Gruppen, Harry; Carré, Patrick; Quinsac, Alain; Poel, de, K.R.

    2017-01-01

    Thermal damage to proteins can reduce their nutritional value. The effects of toasting time on the kinetics of hydrolysis, the resulting molecular weight distribution of 00-rapeseed meal (RSM) and the soluble and insoluble protein fractions separated from the RSM were studied. Hydrolysis was performed with pancreatic proteases to represent in vitro protein digestibility. Increasing the toasting time of RSM linearly decreased the rate of protein hydrolysis of RSM and the insoluble protein frac...

  12. Assembly of citrate gold nanoparticles on hydrophilic monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Vikholm-Lundin, Inger, E-mail: inger.vikholm-lundin@uta.fi [University of Tampere, BioMediTech, Tampere (Finland); Fimlab Laboratories Ltd., Tampere (Finland); Rosqvist, Emil; Ihalainen, Petri [Abo Akademi University, Center for Functional Materials, Laboratory of Physical Chemistry (Finland); Munter, Tony [VTT Technical Research Centre of Finland, Process Chemistry end Environmental Engineering, Tampere (Finland); Honkimaa, Anni [University of Tampere, Department of Virology, School of Medicine, Tampere (Finland); Marjomäki, Varpu [University of Jyväskylä, Department of Biological and Environmental Science, Nanoscience Center, Jyväskylä (Finland); Albers, Willem M. [BioNavis Oy Ltd., Ylöjärvi, Tampere (Finland); Peltonen, Jouko [Abo Akademi University, Center for Functional Materials, Laboratory of Physical Chemistry (Finland)

    2016-08-15

    Highlights: • The self-assembled layers were all hydrophilic with Lipa-pTHMMAA exhibiting close to full wetting. • The polyacrylamide layers smoothen the gold surface to a higher extent than the polyethylene glycol and lipoic acid terminated with an amino group. • SPR resonance curves shift to higher angles and become increasingly damped when large nanoparticles assembled on the surface. • Topographical images confirmed that the highest number of particles were assembled on the polyethylene glycol monolayer. • By increasing the interaction time more particles could be assembled on the surface. - Abstract: Self-assembled monolayers (SAMs) as model surfaces were linked onto planar gold films thorough lipoic acid or disulfide groups. The molecules used were polyethylene glycol (EG-S-S), N-[tris-(hydroxymethyl)methyl]acrylamide polymers with and without lipoic acid (Lipa-pTHMMAA and pTHMMAA) and a lipoic acid triazine derivative (Lipa-MF). All the layers, but Lipa-MF with a primary amino group were hydroxyl terminated. The layers were characterized by contact angle measurements and atomic force microscopy, AFM. Citrate stabilized nanoparticles, AuNPs in water and phosphate buffer were allowed to assemble on the layers for 10 min and the binding was followed in real-time with surface plasmon resonance, SPR. The SPR resonance curves were observed to shift to higher angles and become increasingly damped, while also the peaks strongly broaden when large nanoparticles assembled on the surface. Both the angular shift and the damping of the curve was largest for nanoparticles assembling on the EG-S-S monolayer. High amounts of particles were also assembled on the pTHMMAA layer without the lipoic acid group, but the damping of the curve was considerably lower with a more even distribution of the particles. Topographical images confirmed that the highest number of particles were assembled on the polyethylene glycol monolayer. By increasing the interaction time more

  13. Real-time analysis of insoluble particles in glacial ice using single-particle mass spectrometry

    Science.gov (United States)

    Osman, Matthew; Zawadowicz, Maria A.; Das, Sarah B.; Cziczo, Daniel J.

    2017-11-01

    Insoluble aerosol particles trapped in glacial ice provide insight into past climates, but analysis requires information on climatically relevant particle properties, such as size, abundance, and internal mixing. We present a new analytical method using a time-of-flight single-particle mass spectrometer (SPMS) to determine the composition and size of insoluble particles in glacial ice over an aerodynamic size range of ˜ 0.2-3.0 µm diameter. Using samples from two Greenland ice cores, we developed a procedure to nebulize insoluble particles suspended in melted ice, evaporate condensed liquid from those particles, and transport them to the SPMS for analysis. We further determined size-dependent extraction and instrument transmission efficiencies to investigate the feasibility of determining particle-class-specific mass concentrations. We find SPMS can be used to provide constraints on the aerodynamic size, composition, and relative abundance of most insoluble particulate classes in ice core samples. We describe the importance of post-aqueous processing to particles, a process which occurs due to nebulization of aerosols from an aqueous suspension of originally soluble and insoluble aerosol components. This study represents an initial attempt to use SPMS as an emerging technique for the study of insoluble particulates in ice cores.

  14. An Insoluble Titanium-Lead Anode for Sulfate Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Ferdman, Alla

    2005-05-11

    The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead composite material were investigated. The material containing 20-30 vol.% of lead had optimal combination of mechanical and electrochemical properties. Optimal process parameters to manufacture the anodes were identified. Prototypes having optimized composition and structure were produced for testing in operating conditions of copper electrowinning and EMD production. Bench-scale, mini-pilot scale and pilot scale tests were performed. The test anodes were of both a plate design and a flow-through cylindrical design. The cylindrical anodes were composed of cylinders containing titanium inner rods and fitting over titanium-lead bushings. The cylindrical design allows the electrolyte to flow through the anode, which enhances diffusion of the electrolyte reactants. The cylindrical anodes demonstrate higher mass transport capabilities and increased electrical efficiency compared to the plate anodes. Copper electrowinning represents the primary target market for the titanium-lead anode. A full-size cylindrical anode performance in copper electrowinning conditions was monitored over a year. The test anode to cathode voltage was stable in the 1.8 to 2.0 volt range. Copper cathode morphology was very smooth and uniform. There was no

  15. Polymers of intrinsic microporosity (PIMs): organic materials for membrane separations, heterogeneous catalysis and hydrogen storage.

    Science.gov (United States)

    McKeown, Neil B; Budd, Peter M

    2006-08-01

    This tutorial review describes recent research directed towards the synthesis of polymer-based organic microporous materials termed Polymers of Intrinsic Microporosity (PIMs). PIMs can be prepared either as insoluble networks or soluble polymers with both types giving solids that exhibit analogous behaviour to that of conventional microporous materials such as activated carbons. Soluble PIMs may be processed into thin films for use as highly selective gas separation membranes. Preliminary results also demonstrate the potential of PIMs for heterogeneous catalysis and hydrogen storage.

  16. Potential contact and intraocular lenses based on hydrophilic/hydrophobic sulfonated syndiotactic polystyrene membranes

    Directory of Open Access Journals (Sweden)

    Simona Zuppolini

    2017-10-01

    Full Text Available Crystalline films of syndiotactic polystyrene (s-PS, a commercially available thermoplastic polymer, having a highly hydrophilic amorphous phase, were achieved by using a mild solid-state sulfonation procedure. Despite the used mild process conditions, an easy and uniform sulfonation of the phenyl rings of the amorphous phase is obtained. The crystallinity of the polymer was not affect by the sulfonation degree (S, at least at S less than 20%, and the obtained polymer films show the nanoporous crystalline form of s-PS. As widely reported in literature, the nanoporous nature of the polymer crystalline phase gives to these materials the ability to absorb and release organic molecules of appropriate size and polarity. This property, coupled to transparency, makes these materials potentially useful intraocular lens (IOLs and contact lens applications. Sulfonation procedure and sulfonated film samples characterization by using wide-angle X-ray diffraction (WAXD, Fourier-transform infrared (FTIR and ultraviolet-visible (UV-vis spectroscopy techniques and water sorption tests were reported. Furthermore, the biocompatibility study demonstrated no cytotoxicity and appropriate cell interaction properties for the specific applications.

  17. Opacification of hydrophilic MemoryLens U940A intraocular lenses: analysis of 2 explanted lenses.

    Science.gov (United States)

    Mattová, Jana; Bohácová, Eulália; Murgasová, Zuzana; Kadlec, Róbert; Forgác, Frantisek; Klobusická, Erika; Durcanský, Dusan

    2004-09-01

    To determine the rate of opacification of hydrophilic MemoryLens U940A intraocular lenses (IOLs) (Mentor Ophthalmics, Inc.) in the given cohort and perform a histopathological and spectrophotometer analysis of 2 explanted opacified IOLs. Ophthalmology Department, Faculty Hospital, Nitra, Slovakia. This retrospective study comprised 182 patients (205 eyes) who had implantation of a MemoryLens U940A IOL from June 1997 to June 2000. The patients were examined using a slitlamp to detect the presence of IOL opacification. In 4 cases, the lenses were explanted because of significant opacification and patient-reported problems; 2 lenses were provided for further analysis. One unused reference MemoryLens U940A IOL was also evaluated. All IOL were stained with von Kossa to determine the presence of calcium in the opacification. To confirm the components presence of an ultraviolet (UV) absorber, the IOLs were examined with an Avatar 330 Fourier transfer infrared (IR) spectroscope and a UV visible spectrophotometer (Philips). The IR spectrums for the IOL were identified using an IR spectrum atlas. The opacified IOLs, reference IOL, and the IOL packaging were further examined to determine the presence of silicone. Various amounts of opacification were found on the MemoryLens U940A IOL in 30 eyes (30 patients) (14.63%). Two explanted IOLs were positive for von Kossa staining, proving the presence of calcium deposits; the reference lens staining was negative. Spectrophotometry showed that the reference IOL and opacified IOLs were of the same polymer. The presence of the UV absorber on the benzophenone base was seen in the reference lens but not the opacified IOLs. In contrast, an increased concentration of low-molecular-weight components generated during the degradation of the polymer was present in the opacified lenses. The white cover pf the IOL is of polydimethyl siloxane, a silicone rubber. However, no silicone rubber was present in any examined lens, perhaps because the

  18. New insight into icing and de-icing properties of hydrophobic and hydrophilic structured surfaces based on core-shell particles.

    Science.gov (United States)

    Chanda, Jagannath; Ionov, Leonid; Kirillova, Alina; Synytska, Alla

    2015-12-21

    Icing is an important problem, which often leads to emergency situations in northern countries. The reduction of icing requires a detailed understanding of this process. In this work, we report on a systematic investigation of the effects of geometry and chemical properties of surfaces on the formation of an ice layer, its properties, and thawing. We compare in detail icing and ice thawing on flat and rough hydrophilic and hydrophobic surfaces. We also show advantages and disadvantages of the surfaces of each kind. We demonstrate that water condenses in a liquid form, leading to the formation of a thin continuous water layer on a hydrophilic surface. Meanwhile, separated rounded water droplets are formed on hydrophobic surfaces. As a result of slower heat exchange, the freezing of rounded water droplets on a hydrophobic surface occurs later than the freezing of the continuous water layer on a hydrophilic one. Moreover, growth of ice on hydrophobic surfaces is slower than on the hydrophilic ones, because ice grows due to the condensation of water vapor on already formed ice crystals, and not due to the condensation on the polymer surface. Rough hydrophobic surfaces also demonstrate a very low ice adhesion value, which is because of the reduced contact area with ice. The main disadvantage of hydrophobic and superhydrophobic surfaces is the pinning of water droplets on them after thawing. Flat hydrophilic poly(ethylene glycol)-modified surfaces also exhibit very low ice adhesion, which is due to the very low freezing point of the water-poly(ethylene glycol) mixtures. Water easily leaves from flat hydrophilic poly(ethylene glycol)-modified surfaces, and they quickly become dry. However, the ice growth rate on poly(ethylene glycol)-modified hydrophilic surfaces is the highest. These results indicate that neither purely (super)hydrophobic polymeric surfaces, nor "antifreeze" hydrophilic ones provide an ideal solution to the problem of icing.

  19. Dissolution and solid-state characterization of poorly water-soluble drugs in the presence of a hydrophilic carrier.

    Science.gov (United States)

    Talukder, Rahmat; Reed, Chase; Dürig, Thomas; Hussain, Muhammad

    2011-12-01

    The aim of this study was to investigate the effects of a hydrophilic carrier on the solid-state and dissolution characteristics of poorly water-soluble drugs. Three poorly water-soluble drugs, ibuprofen, carbamazepine, and nifedipine, were studied in combination with hydroxypropyl cellulose (HPC), a low molecular weight hydrophilic polymer, without the use of solvent. A 1:1 drug-polymer ratio was used to evaluate the percent drug release, crystallinity, and wettability. A drug-polymer ratio of 1:4 was also used in co-grinding process to evaluate the effect of polymer levels on drug release. Dissolution studies were carried out in deionized water. Mean dissolution time (MDT) was calculated, and statistical analysis of MDTs was done following a single factor one-way analysis of variance. The dissolution rate of the drugs was enhanced by several folds by the simple process of co-grinding with HPC. X-ray diffraction studies were done to investigate the effects of physical and co-ground mix with HPC on the crystallinity of the drugs, which indicated a partial loss in crystallinity upon grinding. Differential scanning calorimetry studies were performed in order to identify possible solid-state interactions between the respective drugs and HPC. Wettability of the drugs by a 0.5% aqueous HPC solution was compared with that of water and n-hexane using the "Washburn method." Increased wetting and hydrophilization of the drugs by HPC, enlarged surface area due to particle size reduction, and a decrease in the degree of crystallinity were identified as the likely contributors to dissolution rate enhancement.

  20. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    The synthesis of polymer nanocomposites is an integral aspect of polymer nanotechnology. By inserting the nano- metric inorganic compounds, the properties of polymers improve and hence this has a lot of applications depending upon the inorganic material present in the polymers. Sol- vent casting is one of the easiest ...

  1. 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.

  2. 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

  3. Nanobubbles at Hydrophilic Particle-Water Interfaces.

    Science.gov (United States)

    Pan, Gang; He, Guangzhi; Zhang, Meiyi; Zhou, Qin; Tyliszczak, Tolek; Tai, Renzhong; Guo, Jinghua; Bi, Lei; Wang, Lei; Zhang, Honggang

    2016-11-01

    The puzzling persistence of nanobubbles breaks Laplace's law for bubbles, which is of great interest for promising applications in surface processing, H 2 and CO 2 storage, water treatment, and drug delivery. So far, nanobubbles have mostly been reported on hydrophobic planar substrates with atomic flatness. It remains a challenge to quantify nanobubbles on rough and irregular surfaces because of the lack of a characterization technique that can detect both the nanobubble morphology and chemical composition inside individual nanobubble-like objects. Here, by using synchrotron-based scanning transmission soft X-ray microscopy (STXM) with nanometer resolution, we discern nanoscopic gas bubbles of >25 nm with direct in situ proof of O 2 inside the nanobubbles at a hydrophilic particle-water interface under ambient conditions. We find a stable cloud of O 2 nanobubbles at the diatomite particle-water interface hours after oxygen aeration and temperature variation. The in situ technique may be useful for many surface nanobubble-related studies such as material preparation and property manipulation, phase equilibrium, nucleation kinetics, and relationships with chemical composition within the confined nanoscale space. The oxygen nanobubble clouds may be important in modifying particle-water interfaces and offering breakthrough technologies for oxygen delivery in sediment and/or deep water environments.

  4. Fate and Transport of Hydrophobic and Hydrophilic ...

    Science.gov (United States)

    Cyanobacteria (also known as “blue-green algae”) are microscopic organisms that are found in most bodies of water, which can multiply to form harmful algal blooms (HABs) under favorable conditions (i.e., rich nutrients, strong sunlight, and high temperature). Many genera of cyanobacteria are known to produce cyanotoxins such as microcystins (MCs), cylindrospermopsin (CYN), saxitoxins, and anatoxin-a. HABs have been a major health and environmental issue in Europe, Asia as well as the United States. Cyanoxtoxins in water can be partitioned into two categories (i.e., intracellular and extracellular toxins). In most cases, cyanotoxins exist intracellularly in the cytoplasm of cyanobacteria. However, when the cells die or lyse, as well as in response to stressors in the environment, intracellular toxins may be released into the water, becoming extracellular cyanotoxins. According to literature, 95% of MCs are intracellular, but only 50% of CYN is typically intracellular under typical conditions.Cyanotoxins are relatively stable under a variety of water quality conditions and can be persistent in aquatic environments. Conventional drinking water treatment plants (DWTPs), which typically utilize coagulation/flocculation/sedimentation (C/F/S) and sand filtration (SF) have been considered as safe barriers for cyanobacteria and associated intracellular toxins. However, these conventional drinking water treatment processes are ineffective in removing hydrophilic disso

  5. Surface Modification of PDMS and Plastics with Zwitterionic Polymers.

    Science.gov (United States)

    Tanaka, Mutsuo; Kurosawa, Shigeru

    2017-07-01

    Surface modification of PDMS, polycarbonate, and acrylic resin was examined using various methacryl polymers bearing sulfobetaine, phosphoryl choline, and oligoethylene glycol units. We have found that zwitterionic polymers are adsorbed on the PDMS surface treated with plasma. The surface of PDMS is stable to keep high hydrophilicity after a month of the modification. On the other hand, one of sulfobetaine polymers showed distinguished adsorption behavior in the case of polycarbonate surface treated with plasma. Suppression effect for nonspecific adsorption of BSA was evaluated using polycarbonate and acrylic resin modified with the polymers. The modified surfaces showed suppression effect for nonspecific adsorption of BSA compared with the surface only treated with plasma.

  6. Effect of three pluronic polymers on the transport of an organic cation across a POPG bilayer studied by Second Harmonic spectroscopy

    Science.gov (United States)

    Kintali, S. R.; Varshney, G. K.; Das, K.

    2017-09-01

    Pluronic polymer induced transport of an organic cation across a negatively charged POPG membrane bilayer were studied using interfacial selective Second Harmonic (SH) spectroscopic technique. The length of either hydrophilic (poly-ethylene oxide) or hydrophobic (poly-propylene oxide) unit in the polymer was varied to investigate their effect on membrane transport. Membrane transport was observed to depend critically on the length of the hydrophobic segment present in the polymer. Membrane transport studies using polymers which were either 'incorporated' or 'incubated' with the lipid bilayer suggested that bilayer packing plays a critical role in the insertion of polymers having a long hydrophilic chain.

  7. Study on the structure of pitch-polymer compositions by fluorescence microscope.

    Science.gov (United States)

    Makomaski, Grzegorz

    In this work, the results of studies on the evaluation of colloidal structure of coal-tar pitch compositions with selected waste polymers by fluorescence microscope. For pitch-polymer compositions containing 10-50 wt% waste polymer, softening point, coking value and content of components insoluble in toluene and quinoline were carried out. The results indicate that pitch-polymer compositions can be treated as microheterogeneous systems, colloidal and biphase, generally exhibiting uniform dispersion of particles composed of polymer macromolecules and probably of α components of coal-tar pitch.

  8. Chemical modification of poly(vinyl alcohol): evaluation of hydrophilic/lipophilic balance; Poli(alcool vinilico) modificado com cadeias hidrocarbonicas: avaliacao do balanco hidrofilo/lipofilo

    Energy Technology Data Exchange (ETDEWEB)

    Aranha, Isabele B.; Lucas, Elizabete F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas Eloisa B. Mano]. E-mail: elucas@ima.ufrj.br

    2001-12-01

    Poly(vinyl alcohol) terpolymers have been obtained by reaction of partially hydrolized poly(vinyl alcohol) with different acid chlorides. The objective is the preparation of polymers with slight differences in their hydrophilic/lipophilic balance and in the interfacial activities of their solutions. The chemical modifications were characterized by means of {sup 1}H NMR and the polymer properties were evaluated in terms of changes in solubility and surface tension. By chemical modification, polymers with low percentage of hydrophobic group were obtained. The water-soluble polymers obtained did not have the surface tension of their solutions altered. The solubility of the modified polymers decreased markedly, even with low contents of hydrophobic groups. (author)

  9. Cell-Culture Reactor Having a Porous Organic Polymer Membrane

    Science.gov (United States)

    Koontz, Steven L. (Inventor)

    2000-01-01

    A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclosed. The substrate may be subsequently optionally grated with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphory1choline groups, platelet adhesion preventing polymers, albumin adhesion promoters, and the like. The compatibilized substrate may also have a living cell layer adhered thereto. The atomic oxygen is preferably produced by a flowing afterglow microwave discharge, wherein the substrate resides in a sidearm out of the plasma. Also, methods for culturing cells for various purposes using the various membranes are disclosed as well. Also disclosed are porous organic polymers having a distributed pore chemistry (DPC) comprising hydrophilic and hydrophobic regions, and a method for making the DPC by exposing the polymer to atomic oxygen wherein the rate of hydrophilization is greater than the rate of mass loss.

  10. Self-restoring polymer brushes under tribological stress and the biomedical applications

    DEFF Research Database (Denmark)

    Røn, Troels; Javakhishvili, Irakli; Hvilsted, Søren

    2016-01-01

    ”, the hydrophilic polymer chains of amphiphilic diblock copolymers dispersed within a poly(dimethylsiloxane) (PDMS) network are selectively segregated upon exposure to aqueous solution. This allows formation of extremely stable brush-like polymer layers. Tribological application of inverted grafting-to approach......For biological and mechanical systems involving moving parts, surface slipperiness is often a critical attribute for their optimal functions. Surface grafting with hydrophilic polymers is a powerful means to render materials slippery in aqueous environment. In “inverted grafting-to approach...

  11. Production and cytotoxicity of extracellular insoluble and droplets of soluble melanin by Streptomyces lusitanus DMZ-3.

    Science.gov (United States)

    Madhusudhan, D N; Mazhari, Bi Bi Zainab; Dastager, Syed G; Agsar, Dayanand

    2014-01-01

    A Streptomyces lusitanus DMZ-3 strain with potential to synthesize both insoluble and soluble melanins was detected. Melanins are quite distinguished based on their solubility for varied biotechnological applications. The present investigation reveals the enhanced production of insoluble and soluble melanins in tyrosine medium by a single culture. Streptomyces lusitanus DMZ-3 was characterized by 16S rRNA gene analysis. An enhanced production of 5.29 g/L insoluble melanin was achieved in a submerged bioprocess following response surface methodology. Combined interactive effect of temperature (50°C), pH (8.5), tyrosine (2.0 g/L), and beef extract (0.5 g/L) were found to be critical variables for enhanced production in central composite design analysis. An optimized indigenous slant culture system was an innovative approach for the successful production (264 mg/L) of pure soluble melanin from the droplets formed on the surface of the culture. Both insoluble and soluble melanins were confirmed and characterized by Chemical, reactions, UV, FTIR, and TLC analysis. First time, cytotoxic study of melanin using brine shrimps was reported. Maximum cytotoxic activity of soluble melanin was Lc50-0.40 µg/mL and insoluble melanin was Lc50-0.80 µg/mL.

  12. Production and Cytotoxicity of Extracellular Insoluble and Droplets of Soluble Melanin by Streptomyces lusitanus DMZ-3

    Directory of Open Access Journals (Sweden)

    D. N. Madhusudhan

    2014-01-01

    Full Text Available A Streptomyces lusitanus DMZ-3 strain with potential to synthesize both insoluble and soluble melanins was detected. Melanins are quite distinguished based on their solubility for varied biotechnological applications. The present investigation reveals the enhanced production of insoluble and soluble melanins in tyrosine medium by a single culture. Streptomyces lusitanus DMZ-3 was characterized by 16S rRNA gene analysis. An enhanced production of 5.29 g/L insoluble melanin was achieved in a submerged bioprocess following response surface methodology. Combined interactive effect of temperature (50°C, pH (8.5, tyrosine (2.0 g/L, and beef extract (0.5 g/L were found to be critical variables for enhanced production in central composite design analysis. An optimized indigenous slant culture system was an innovative approach for the successful production (264 mg/L of pure soluble melanin from the droplets formed on the surface of the culture. Both insoluble and soluble melanins were confirmed and characterized by Chemical, reactions, UV, FTIR, and TLC analysis. First time, cytotoxic study of melanin using brine shrimps was reported. Maximum cytotoxic activity of soluble melanin was Lc50-0.40 µg/mL and insoluble melanin was Lc50-0.80 µg/mL.

  13. Mass transfer mechanism in hydrophilic interaction chromatography.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2013-08-09

    The mass transfer mechanism in HILIC was investigated in depth. The reduced heights equivalent to a theoretical plate (HETP) of five low molecular weigh compounds with retention factors of -0.05 (slight exclusion from the surface due to the presence of a water-rich layer in which naphthalene is insoluble) to 3.64 were measured at room temperature for a 4.6mm×100mm column packed with 3.5μm 140Å XBridge HILIC particles in a wide range of flow velocities. The mobile phase was a buffered acetonitrile-water mixture (92.5/7.5, v/v). Using a physically reliable model of effective diffusion in binary composite media (Torquato's model), the longitudinal diffusion and solid-liquid mass transfer resistance reduced HETP terms were measured. The reduced short-range eddy dispersion HETP was taken from the literature data. The long-range reduced HETP was directly measured from the subtraction of these HETP terms to the overall HETP measured from moment analysis. In contrast to RPLC, the plots of the reduced HETP versus the reduced velocity depend weakly on the retention factor, due to the constant, low intra-particle diffusivity observed in HILIC. So, the reduced longitudinal diffusion HETP is smaller and the reduced solid-liquid mass transfer resistance HETP is larger in HILIC than in RPLC. Whereas border effects can be concealed in RPLC for retained analytes due to fast radial equilibration across the column diameter, a residual long-range eddy dispersion term persists in 4.6mm I.D. HILIC columns, even at very slow flow rates. Experiments show that the minor differences in the long-range eddy dispersion term between analytes having different retention factors is directly correlated to the reciprocal of their bulk diffusion coefficient. The performance of HILIC columns packed with fine particles is then more sensitive to the inlet sample distribution and to the outlet sample collection than RPLC columns due to the relatively poor radial mixing controlled by lateral diffusion

  14. Production of insoluble dextran using cell-bound dextransucrase of Leuconostoc mesenteroides NRRL B-523.

    Science.gov (United States)

    Padmanabhan, Prabhu Arcot; Kim, Dong-Shik

    2002-09-27

    Water-insoluble, cell-free dextran biosynthesis from Leuconostoc mesenteroides NRRL B-523 has been examined. Cell-bound dextransucrase is used to produce cell-free dextran in a sucrose-rich acetate buffer medium. A comparison between the soluble and insoluble dextrans is made for various sucrose concentrations, and 15% sucrose gave the highest amount of cell-free dextran for a given time. L. mesenteroides B-523 produces more insoluble dextran than soluble dextran. The near cell-free synthesis was validated in a batch reactor, by monitoring the cell growth which is a small (10(6)-10(7) CFU/mL) and constant value throughout the synthesis.

  15. Safety of hydrophilic guidewires used for side-branch protection during stenting and proximal optimization technique in coronary bifurcation lesions

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Arka [Division of Cardiology, University of Alabama-Birmingham (United States); Brott, Brigitta C. [Division of Cardiology, University of Alabama-Birmingham (United States); Department of Biomedical Engineering, University of Alabama-Birmingham (United States); Foley, Robin [Department of Material Science and Engineering, University of Alabama-Birmingham (United States); Alli, Oluseun; Sasse, Mark; Ahmed, Mustafa; Al Solaiman, Firas; Reddy, Gautam; Ather, Sameer [Division of Cardiology, University of Alabama-Birmingham (United States); Leesar, Massoud A., E-mail: mleesar@uab.edu [Division of Cardiology, University of Alabama-Birmingham (United States)

    2016-10-15

    Background and propose: In coronary bifurcation lesions (CBL), hydrophilic guidewires used for side-branch (SB) protection can be withdrawn from underneath the stent easier than other wires. However, the safety of which has not been investigated. Methods/materials: We performed scanning electron microscopic (SEM) examination of hydrophilic wires – the Whisper and Runthrough wires – used for SB protection during stenting and proximal optimization technique (POT) in 30 patients with CBL. The distal 15 cm of the wire was examined every 1 mm by SEM and 4500 segments were analyzed to investigate for wire fracture, polymer shearing (PS), and its correlations with post-stenting creatine kinase (CK)-MB release. Results: SEM examination showed no evidence for wire fracture. The total area of PS and the largest defect on the wire were significantly larger with the Whisper wire versus the Runthrough wire (0.15 ± 0.04 mm{sup 2} vs. 0.026 ± 0.01 mm{sup 2} and 0.04 ± 0.05 mm{sup 2} vs. 0.01 ± 0.01 mm{sup 2}; P < 0.05, respectively). The total length of PS and the longest defect on the wire were significantly longer with the Whisper wire vs. the Runthrough wire (12.1 ± 14.5 mm vs. 2.7 ± 3.0 mm and 2.9 ± 4.2 mm vs. 1.0 ± 1.2 mm; P < 0.05, respectively), but there were weak correlations between the extents of PS with CK-MB release. Conclusions: Hydrophilic guidewires may be safely used for SB protection during stenting and POT in CBLs. The extent of PS was significantly greater with the Whisper wire than with the Runthrough wire, but its correlation with post-stenting CK-MB release was weak. - Highlights: • There was no wire fracture by jailing hydrophilic wires. • There was no wire entrapment by jailing hydrophilic wires. • There were weak correlations between polymer shearing and creatine kinase-MB levels. • The impact of polymer shearing on myocardial infraction warrants future studies.

  16. 3D Printing PDMS Elastomer in a Hydrophilic Support Bath via Freeform Reversible Embedding.

    Science.gov (United States)

    Hinton, Thomas J; Hudson, Andrew; Pusch, Kira; Lee, Andrew; Feinberg, Adam W

    2016-10-10

    Polydimethylsiloxane (PDMS) elastomer is used in a wide range of biomaterial applications including microfluidics, cell culture substrates, flexible electronics, and medical devices. However, it has proved challenging to 3D print PDMS in complex structures due to its low elastic modulus and need for support during the printing process. Here we demonstrate the 3D printing of hydrophobic PDMS prepolymer resins within a hydrophilic Carbopol gel support via freeform reversible embedding (FRE). In the FRE printing process, the Carbopol support acts as a Bingham plastic that yields and fluidizes when the syringe tip of the 3D printer moves through it, but acts as a solid for the PDMS extruded within it. This, in combination with the immiscibility of hydrophobic PDMS in the hydrophilic Carbopol, confines the PDMS prepolymer within the support for curing times up to 72 h while maintaining dimensional stability. After printing and curing, the Carbopol support gel releases the embedded PDMS prints by using phosphate buffered saline solution to reduce the Carbopol yield stress. As proof-of-concept, we used Sylgard 184 PDMS to 3D print linear and helical filaments via continuous extrusion and cylindrical and helical tubes via layer-by-layer fabrication. Importantly, we show that the 3D printed tubes were manifold and perfusable. The results demonstrate that hydrophobic polymers with low viscosity and long cure times can be 3D printed using a hydrophilic support, expanding the range of biomaterials that can be used in additive manufacturing. Further, by implementing the technology using low cost open-source hardware and software tools, the FRE printing technique can be rapidly implemented for research applications.

  17. Interaction mechanism between hydrophobic and hydrophilic surfaces: using polystyrene and mica as a model system.

    Science.gov (United States)

    Faghihnejad, Ali; Zeng, Hongbo

    2013-10-08

    The interactions between hydrophobic and hydrophilic molecules, particles, or surfaces occur in many biological phenomena and industrial processes. In this work, polystyrene (PS) and mica were chosen as a model system to investigate the interaction mechanism between hydrophilic and hydrophobic surfaces. Using a surface forces apparatus (SFA) coupled with a top-view optical microscope, interaction forces between PS and mica surfaces were directly probed in five different electrolyte solutions (i.e., NaCl, CaCl2, NaOH, HCl, and CH3COOH) of various concentrations. Long-range repulsion was observed in low electrolyte concentration (e.g., 0.001 M) which was mainly due to the presence of microscopic and submicroscopic bubbles on PS surface. A modified Derjaguin-Landau-Verwey-Overbeek (DLVO) theory well fits the interaction forces by taking into account the effect of bubbles on PS surface. The range of the repulsion was dramatically reduced in 1.0 M solutions of NaCl, CaCl2, and NaOH but did not significantly change in 1.0 M HCl and CH3COOH, which was due to ion specificity effect on the formation and stability of bubbles on PS surface. The range of repulsion was also significantly reduced to hydrophobic attraction of the untreated PS-PS system to pure repulsion between untreated PS and treated PS, demonstrating the important role of surface hydrophobicity on the formation and stability of bubbles on substrates. Our results indicate that DLVO forces dominate the interaction between hydrophilic surface (i.e., mica) and hydrophobic polymer (i.e., PS), while the types of electrolytes (ion specificity), electrolyte concentration, degassing, and surface hydrophobicity can significantly affect the formation and stability of bubbles on the interacting surfaces, thus affecting the range and magnitude of the interaction forces.

  18. The Properties of HPMC:PEO Extended Release Hydrophilic Matrices and their Response to Ionic Environments.

    Science.gov (United States)

    Hu, Anran; Chen, Chen; Mantle, Michael D; Wolf, Bettina; Gladden, Lynn F; Rajabi-Siahboomi, Ali; Missaghi, Shahrzad; Mason, Laura; Melia, Colin D

    2017-05-01

    Investigate the extended release behaviour of compacts containing mixtures of hydrophilic HPMC and PEO in hydrating media of differing ionic strengths. The extended release behaviour of various HPMC:PEO compacts was investigated using dissolution testing, confocal microscopy and magnetic resonance imaging, with respect to polymer ratio and ionic strength of the hydrating media. Increasing HPMC content gave longer extended release times, but a greater sensitivity to high ionic dissolution environments. Increasing PEO content reduced this sensitivity. The addition of PEO to a predominantly HPMC matrix reduced release rate sensitivity to high ionic environments. Confocal microscopy of early gel layer development showed the two polymers appeared to contribute independently to gel layer structure whilst together forming a coherent and effective diffusion barrier. There was some evidence that poorly swollen HPMC particles added a tortuosity barrier to the gel layer in high ionic strength environments, resulting in prolonged extended release. MRI provides unique, non-invasive spatially resolved information from within the HPMC:PEO compacts that furthers our understanding of USP 1 and USP 4 dissolution data. Confocal microscopy and MRI data show that combinations of HPMC and PEO have advantageous extended release properties, in comparison with matrices containing a single polymer.

  19. Block ionomer micellar nanoparticles from double hydrophilic copolymers, classifications and promises for delivery of cancer chemotherapeutics.

    Science.gov (United States)

    Abolmaali, S S; Tamaddon, A M; Salmanpour, M; Mohammadi, S; Dinarvand, R

    2017-06-15

    A class of double hydrophilic copolymers comprising ionic and nonionic water-soluble blocks, which are also called block ionomers, represent an interesting type of polymer assembly forming stable, homogeneous core-corona dispersions. They exhibit the solution behavior of normal polyelectrolytes, whereas assembly into micelle, vesicle or disk morphology happens by an external stimulus (pH, temperature or ionic strength) or complex formation with metal ions, ionic surfactants, polyelectrolytes, etc. Temperature, pH, redox or salt sensitivity affords a unique opportunity to control the triggered release of payloads accommodated through electrostatic interaction, coordination or chemical conjugation. Moreover, the non-ionic block provides the surface passivation, prolongation of the blood circulation and tumor accumulation, supporting targeted delivery of chemotherapeutic agents based on pathophysiology of tumor microenvironment. Potentiation of antitumor activity, sensitization of the resistant tumors, increased tolerated dose and translation into clinical practice are among their most intriguing characteristics. Their high functionality has been suggested for co-delivery of multiple agents for reversal of chemo-resistance as well as simultaneous therapy and diagnostics. Nevertheless, some stability concerns may be raised due to the polymer disassembly beyond a critical concentration of pH, salt and polyion concentration that can be modulated by introducing crosslinks between the polymer chains (Nano-networks). Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Effect of Anionic Polymers on Drug Loading and Release from ...

    African Journals Online (AJOL)

    or sodium alginate as anionic polymers for the delivery of clindamycin phosphate as a model hydrophilic cationic ... Controlled drug delivery, enhanced bioavailability of entrapped drugs [5], and/or improved tissue distribution, good tolerability, and drug targeting have been ... certain types of bacterial infections, including.

  1. Surface Deposition and Phase Behavior of Oppositely Charged Polyion–Surfactant Ion Complexes. Delivery of Silicone Oil Emulsions to Hydrophobic and Hydrophilic Surfaces

    Science.gov (United States)

    2011-01-01

    The adsorption from mixed polyelectrolyte–surfactant solutions at hydrophobized silica surfaces was investigated by in situ null-ellipsometry, and compared to similar measurements for hydrophilic silica surfaces. Three synthetic cationic copolymers of varying hydrophobicity and one cationic hydroxyethyl cellulose were compared in mixtures with the anionic surfactant sodium dodecylsulfate (SDS) in the absence or presence of a dilute silicone oil emulsion. The adsorption behavior was mapped while stepwise increasing the concentration of SDS to a polyelectrolyte solution of constant concentration. The effect on the deposition of dilution of the bulk solution in contact with the surface was also investigated by gradual replacement of the bulk solution with 1 mM aqueous NaCl. An adsorbed layer remained after complete exchange of the polyelectrolyte/surfactant solution for aqueous NaCl. In most cases, there was a codeposition of silicone oil droplets, if such droplets were present in the formulation before dilution. The overall features of the deposition were similar at hydrophobic and hydrophilic surfaces, but there were also notable differences. SDS molecules adsorbed selectively at the hydrophobized silica surface, but not at the hydrophilic silica, which influenced the coadsorption of the cationic polymers. The largest amount of deposited material after dilution was found for hydrophilic silica and for the least-hydrophobic cationic polymers. For the least-hydrophobic polyions, no significant codeposition of silicone oil was detected at hydrophobized silica after dilution if the initial SDS concentration was high. PMID:21667982

  2. Liposomes as vehicles for water insoluble platinum-based potential drug

    DEFF Research Database (Denmark)

    Kaluđerović, Goran N; Dietrich, Andrea; Kommera, Harish

    2012-01-01

    Formulation of liposome delivery system loaded with water insoluble 2-(4-(tetrahydro-2H-pyran-2-yloxy)-undecyl)-propane-1,3-diamminedichloroplatinum(II), LipoTHP-C11 was carried out. The particle size distributions were determined by dynamic light scattering and asymmetrical flow field-flow fract......Formulation of liposome delivery system loaded with water insoluble 2-(4-(tetrahydro-2H-pyran-2-yloxy)-undecyl)-propane-1,3-diamminedichloroplatinum(II), LipoTHP-C11 was carried out. The particle size distributions were determined by dynamic light scattering and asymmetrical flow field...

  3. Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

    Directory of Open Access Journals (Sweden)

    Chern Chiet Eng

    2013-01-01

    Full Text Available The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA/Polycaprolactone (PCL blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD, Fourier Transform Infrared Spectroscopy (FTIR, Thermogravimetric Analysis (TGA, Dynamic Mechanical Analysis (DMA, Scanning Electron Microscopy (SEM, and Transmission Electron Microscopy (TEM. FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

  4. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

    Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

    The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer

  5. Swollen-dry-layer model for the pervaporation of ethanol-water solution through hydrophilic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Ito, A.; Watanabe, K.; Feng, Y. [Niigata Univ. (Japan)

    1995-09-01

    A swollen-dry-layer model is presented for the pervaporation of ethanol-water solution through hydrophilic polymer membranes: poly(vinyl alcohol) and carboxymethyl cellulose. Independent measurements were conducted of the sorption equilibrium, the hydraulic permeation rates through the swollen membranes, and the permeabilities of ethanol and water vapors. The hydraulic permeabilities were estimated from the mutual diffusion coefficients of solution in the swollen membrane. Sorption behavior and hydraulic permeabilities showed a dependence on feed concentration. Vapor permeabilities of water and ethanol through dry membranes differ by a factor of about 20. Comparisons between the experimental data from the pervaporation run and the results calculated from the model were made. The model offers a quantitative explanation for the dependency of selectivity and flux on feed concentration. The model explained that the flux dependency caused by a change in the swollen-dry-layer ratio, and that the selectivity is governed by vapor permeabilities through the dry layer.

  6. Production of gliadin-poly(ethyl cyanoacrylate) nanoparticles for hydrophilic coating

    Science.gov (United States)

    Kim, Sanghoon; Kim, Yeon Seok

    2014-02-01

    Cyanoacrylate nanoparticles have been usually prepared by anionic polymerization initiated by hydroxyl ions derived from dissociation of water. In the current research, amine groups on the surface of gliadin aggregates were utilized as initiator for the polymerization of ethyl cyanoacrylate (ECA). Gliadin, a protein found in the endosperms of wheat ( Triticum aestivum L.), is not soluble in water, but dissolves in aqueous ethanol in the form of aggregates. As a result of the reaction with ECA monomers, gliadin molecules are chemically bound to poly(ethyl cyanoacrylate) (PECA) chains. The nanoparticles thus produced are made up of block copolymers that are consisted of hydrophilic moiety (gliadin) and hydrophobic moiety (PECA). The suspension containing these nanoparticles showed an excellent coating capability on the surface of hydrophobic materials such as glass or plastics. A simple spray coating changed the wetting property of the material instantly and dramatically. Since both protein and poly(alkyl cyanoacrylate) are degradable polymers, the developed nanoparticles are degradable.

  7. Morphology-controlled growth of perylene derivative induced by double-hydrophilic block copolymers

    Directory of Open Access Journals (Sweden)

    Minghua Huang

    2016-01-01

    Full Text Available Controlled growth of technically relevant perylene derivative 3, 4, 9, 10-perylenetetracarboxylic acid potassium salt (PTCAPS, with tuneable morpologies, has been successfully realized by a recrystallization method using a double-hydrophilic block copolymer poly (ethylene glycol-block poly (ethyleneimine (PEG-b-PEI as the structure directing agent. The {001} faces of PTCAPS are most polar and adsorb the oppositively charged polymer additive PEG-b-PEI well by electrostatic attraction. By simply adjusting the PEG-b-PEI concentration, systematic morphogenesis of PTCAPS from plates to microparticles composed of various plates splaying outwards could be realized. Furthermore, the variation of pH value of the recrystallization solution could induce the change of the interaction strength between PEG-b-PEI additive and PTCAPS and thus modify the morphology of PTCAPS from microparticles composed of various plates to ultralong microbelts.

  8. Synthesis of Thermo-Responsive Polymer via Radical (Co)polymerization of N,N-Dimethyl-α-(hydroxymethyl)acrylamide with N,N-Diethylacrylamide

    National Research Council Canada - National Science Library

    Kohsaka, Yasuhiro; Tanimoto, Yoshiaki

    2016-01-01

    .... In this article, we report the first example of radical polymerization of α-functionalized N,N-disubstituted acrylamide affording thermo-responsive hydrophilic polymers. N,N-dimethyl-α-(hydroxymethyl)acrylamide (DMαHAA) was (co...

  9. Considerations in binding diblock copolymers on hydrophilic alginate beads for providing an immunoprotective membrane

    Science.gov (United States)

    Spasojevic, Milica; Bhujbal, Swapnil; Paredes, Genaro; de Haan, Bart J; Schouten, Arend J; de Vos, Paul

    2014-01-01

    Alginate-based microcapsules are being proposed for treatment of many types of diseases. A major obstacle however in the successes is that these capsules are having large lab-to-lab variations. To make the process more reproducible, we propose to cover the surface of alginate capsules with diblock polymers that can form polymer brushes. In the present study, we describe the stepwise considerations for successful application of diblock copolymer of polyethylene glycol (PEG) and poly-l-lysine (PLL) on the surface of alginate beads. Special procedures had to be designed as alginate beads are hydrophilic and most protocols are designed for hydrophobic biomaterials. The successful attachment of diblock copolymer and the presence of PEG blocks on the surface of the capsules were studied by fluorescence microscopy. Longer time periods, that is, 30–60 min, are required to achieve saturation of the surface. The block lengths influenced the strength of the capsules. Shorter PLL blocks resulted in less stable capsules. Adequate permeability of the capsules was achieved with poly(ethylene glycol)-block-poly(l-lysine hydrochloride) (PEG454-b-PLL100) diblock copolymers. The capsules were a barrier for immunoglobulin G. The PEG454-b-PLL100 capsules have similar mechanical properties as PLL capsules. Minor immune activation of nuclear factor κB in THP-1 monocytes was observed with both PLL and PEG454-b-PLL100 capsules prepared from purified alginate. Our results show that we can successfully apply block copolymers on the surface of hydrophilic alginate beads without interfering with the physicochemical properties. PMID:23853069

  10. Neutral hydrophilic coatings for capillary electrophoresis prepared by controlled radical polymerization.

    Science.gov (United States)

    Navarro, Fabián H; Gómez, Jorge E; Espinal, José H; Sandoval, Junior E

    2016-12-15

    In the present study, porous silica particles as well as impervious fused-silica wafers and capillary tubes were modified with hydrophilic polymers (hydroxylated polyacrylamides and polyacrylates), using a surface-confined grafting procedure based on atom transfer radical polymerization (ATRP) which was also surface-initiated from α-bromoisobutyryl groups. Initiator immobilization was achieved by hydrosilylation of allyl alcohol on hydride silica followed by esterification of the resulting propanol-bonded surface with α-bromoisobutyryl bromide. Elemental analysis, IR and NMR spectroscopies on silica micro-particles, atomic force microscopy, ellipsometry and profilometry on fused-silica wafers, as well as CE on fused-silica tubes were used to characterize the chemically modified silica substrate at different stages. We studied the effect of monomer concentration as well as cross-linker on the ability of the polymer film to reduce electroosmosis and to prevent protein adsorption (i. e., its non-fouling capabilities) and found that the former was rather insensitive to both parameters. Surface deactivation towards adsorption was somewhat more susceptible to monomer concentration and appeared also to be favored by a low concentration of the cross-linker. The results show that hydrophilic polyacrylamide and polyacrylate coatings of controlled thickness can be prepared by ATRP under very mild polymerization conditions (aqueous solvent, room temperature and short reaction times) and that the coated capillary tubes exhibit high efficiencies for protein separations (0.3-0.6 million theoretical plates per meter) as well as long-term hydrolytic stability under the inherently harsh conditions of capillary isoelectric focusing. Additionally, there was no adsorption of lysozyme on the coated surface as indicated by a complete recovery of the basic enzyme. Furthermore, since polymerization is confined to the inner capillary surface, simple precautions (e.g., solution filtration

  11. Fruiting bodies of Hericium erinaceus (Bull. Pers. – a new source of water-insoluble (1→3-α-d-glucan

    Directory of Open Access Journals (Sweden)

    Adrian Wiater

    2016-09-01

    Full Text Available A water-insoluble polysaccharide (WIP was isolated from the fruiting bodies of Hericium erinaceus HE01 by an alkaline solution with the yield of 5%. Structural and compositional analyses by total acid hydrolysis, methylation analysis, FT-IR, FT-Raman, and 1H NMR spectroscopy as well as other instrumental techniques showed predominantly glucose linked by α-glycosidic bonds and small amounts of mannose, xylose, rhamnose, galactose, and ribose. The methylation analysis showed that (1→3-linked Glcp is the major constituent (70.8% of the polymer, while the 3,4 substituted d-Glcp represents the main branching residue of the glucan. The presence of (1→3-α-d-glucan in the hyphae of H. erinaceus was additionally confirmed by the use of specific fluorophore-labeled antibodies.

  12. A kinetic model for heterogeneous condensation of vapor on an insoluble spherical particle.

    Science.gov (United States)

    Luo, Xisheng; Fan, Yu; Qin, Fenghua; Gui, Huaqiao; Liu, Jianguo

    2014-01-14

    A kinetic model is developed to describe the heterogeneous condensation of vapor on an insoluble spherical particle. This new model considers two mechanisms of cluster growth: direct addition of water molecules from the vapor and surface diffusion of adsorbed water molecules on the particle. The effect of line tension is also included in the model. For the first time, the exact expression of evaporation coefficient is derived for heterogeneous condensation of vapor on an insoluble spherical particle by using the detailed balance. The obtained expression of evaporation coefficient is proved to be also correct in the homogeneous condensation and the heterogeneous condensation on a planar solid surface. The contributions of the two mechanisms to heterogeneous condensation including the effect of line tension are evaluated and analysed. It is found that the cluster growth via surface diffusion of adsorbed water molecules on the particle is more important than the direct addition from the vapor. As an example of our model applications, the growth rate of the cap shaped droplet on the insoluble spherical particle is derived. Our evaluation shows that the growth rate of droplet in heterogeneous condensation is larger than that in homogeneous condensation. These results indicate that an explicit kinetic model is benefit to the study of heterogeneous condensation on an insoluble spherical particle.

  13. Resolubilization of Protein from Water-Insoluble Phlorotannin-Protein Complexes upon Acidification

    NARCIS (Netherlands)

    Vissers, Anne M.; Blok, Annelies E.; Westphal, Adrie H.; Hendriks, Wouter H.; Gruppen, Harry; Vincken, Jean Paul

    2017-01-01

    Marine phlorotannins (PhT) from Laminaria digitata might protect feed proteins from ruminal digestion by formation of insoluble non-covalent tannin-protein complexes at rumen pH (6-7). Formation and disintegration of PhT-protein complexes was studied with β-casein (random coil) and bovine serum

  14. INSOLUBLE HYDROPHOBIN COMPLEXES IN THE WALLS OF SCHIZOPHYLLUM-COMMUNE AND OTHER FILAMENTOUS FUNGI

    NARCIS (Netherlands)

    DEVRIES, OMH; FEKKES, MP; WOSTEN, HAB; WESSELS, JGH

    Two closely related cysteine-rich hydrophobic proteins, Sc3p and Sc4p, of the basidiomycete Schizophyllum commune are developmentally regulated and associated with the walls of aerial hyphae and fruit-body hyphae. They are present in the walls as hot-SDS-insoluble complexes which can be extracted

  15. Soluble Antioxidant Compounds Regenerate the Antioxidants Bound to Insoluble Parts of Foods

    NARCIS (Netherlands)

    Celik, E.E.; Gökmen, V.; Fogliano, V.

    2013-01-01

    This study aimed to investigate the regeneration potential of antioxidant capacity of an insoluble food matrix. Investigations were performed in vitro with several food matrices rich in dietary fiber (DF) and bound antioxidants. After removal of the soluble fraction, the antioxidant capacity (AC) of

  16. Effects of Toasting Time on Digestive Hydrolysis of Soluble and Insoluble 00-Rapeseed Meal Proteins

    NARCIS (Netherlands)

    Salazar-Villanea, Sergio; Bruininx, Erik M.A.M.; Gruppen, Harry; Carré, Patrick; Quinsac, Alain; Poel, van der Thomas

    2017-01-01

    Thermal damage to proteins can reduce their nutritional value. The effects of toasting time on the kinetics of hydrolysis, the resulting molecular weight distribution of 00-rapeseed meal (RSM) and the soluble and insoluble protein fractions separated from the RSM were studied. Hydrolysis was

  17. the role of soluble and insoluble fibers during fermentation of Chicory root pulp

    NARCIS (Netherlands)

    Ramasamy, U.

    2014-01-01

     

    This thesis was aimed at understanding the in vitro fermentability of soluble and insoluble fibers in chicory root pulp (CRP). First, CRP and ensiled chicory root pulp (ECRP) were characterized for cell wall polysaccharides (CWPs). Both CRP and ECRP were rich

  18. Supramolecular Polymers

    Science.gov (United States)

    Stupp, S. I.; Keser, M.; Huggins, K. E.; Tew, G.; Li, L. S.; Whitaker, C.

    1997-03-01

    An interesting target in polymer science is to find pathways to highly regular supramolecular units with dimensions similar to those of high molar mass linear or hyperbranched polymers. These units lack a polymeric backbone but could serve as precursors to shape invariant covalent polymers analogous to folded proteins. We are pursuing access to these polymers with designed molecules programmed to assemble into nanostructures of regular shape and dimension. We have discovered systems of miniaturized triblock copolymers that yield supramolecular polymers. These supramolecular polymers are shaped as mushroom nanostructures, and form materials with interesting surface and optical properties. Molecular modeling indicates that a balance of aggregation and hard core repulsive forces among structural units may be responsible for the formation of these supramolecular polymers.

  19. Study of polymer dispersed liquid crystal film based on amphiphilic polymer matrix

    Directory of Open Access Journals (Sweden)

    Farzana Ahmad

    2017-05-01

    Full Text Available Polymer dispersed liquid crystal (PDLC films’ morphologies and electro-optical properties have been mostly investigated on the method of polymerization, rate of reaction, the relative amount, characteristic, and temperature of the LC/monomer mixtures; in chorus with the molecular associations existing among the LC, monomer molecules and with the glass. In this effort the molecular associations of polymer matrix having hydrophilic and hydrophobic characteristics are considered with the LC. Here the hydrophilic/hydrophobic interactions of material are deduced equally accountable for change in the morphology, electro-optical properties and phase separation of PDLC films. For such investigations the spectroscopic techniques such as Fourier transform infrared (FTIR spectroscopy, polarized optical microscopy (POM and phase transition temperatures have been implemented which appreciably elucidate the subsequent studies.

  20. Platform Approach to Produce Polymer Nanoparticles with Modular Functionality from Amphiphilic Block Copolymer Stabilizers

    Science.gov (United States)

    2014-04-01

    block weight percentages for all BCPs are in the range of 75 to 85 wt%. Furthermore, the calculated hydrophilic-lipophilic balance ( HLB ) for each...polymer resides in the range of 14‒16. HLB values greater than 12 are predicted to stabilize oil-in-water emulsions.21 Table 1. Synthesized BCPs...light scattering DMF dimethylformamide DMSO dimethyl sulfoxide EO ethylene oxide FTIR HLB Fourier transform infrared spectroscopy hydrophilic

  1. Novel Hydrogels from Telechelic Polymers

    Science.gov (United States)

    Taribagil, Rajiv R.

    The last two decades have seen telechelic polymers support an increasing number of applications as stabilizers and flow modifiers in fields as varied as pharmaceutics, paints and oil recovery. Mainly consisting of a long hydrophilic block end-capped with hydrophobic blocks, these polymers form gels at modest concentrations, comprising hydrophobic junctions with hydrophilic blocks bridging these junctions. This thesis examines two different types of telechelic polymer hydrogels: concentrated dispersions of telechelic triblock copolymers and dilute solutions of wormlike micelles cross-linked by hydrophobically end-capped polymers. Aqueous gels of telechelic poly(ethylene oxide) (PEO)-based triblock polymers, with homo and hetero combinations of 1,2-polybutadiene (PB) and poly(perfluoropropylene oxide) (PFPO) as hydrophobic end-blocks, were investigated using a combination of cryogenic scanning electron microscopy and small-angle neutron scattering. The PB-b-PEO-b-PB copolymers formed networks of spherical micelles at all concentrations as expected, albeit with significant spatial heterogeneity that diminished with increasing concentration. The PFPO-b-PEO-b-PFPO copolymers also formed networks by aggregation of the end-blocks, but the PFPO blocks tended to adopt disk-like or even sheet-like structures. This is attributed to the extremely high interfacial tension of PFPO with water and is consistent with the "super-strong" segregation regime behavior. The heterotelechelic PB-b-PEO- b-PFPO terpolymers adopted a quite different structure, namely an intricate bicontinuous open-cell foam, with cells on the order of 500 nm in size and cell walls composed of PFPO disks embedded in PB sheets. These various network structures illustrate the potential of using end-block chemistry to manipulate both the morphology and the physical properties of polymer gels. Dilute aqueous solutions containing 1 wt% cetyltrimethylammonium tosylate, a surfactant well recognized to form wormlike

  2. Biochemical Composition and Assembly of Biosilica-associated Insoluble Organic Matrices from the Diatom Thalassiosira pseudonana*

    Science.gov (United States)

    Kotzsch, Alexander; Pawolski, Damian; Milentyev, Alexander; Shevchenko, Anna; Scheffel, André; Poulsen, Nicole; Shevchenko, Andrej; Kröger, Nils

    2016-01-01

    The nano- and micropatterned biosilica cell walls of diatoms are remarkable examples of biological morphogenesis and possess highly interesting material properties. Only recently has it been demonstrated that biosilica-associated organic structures with specific nanopatterns (termed insoluble organic matrices) are general components of diatom biosilica. The model diatom Thalassiosira pseudonana contains three types of insoluble organic matrices: chitin meshworks, organic microrings, and organic microplates, the latter being described in the present study for the first time. To date, little is known about the molecular composition, intracellular assembly, and biological functions of organic matrices. Here we have performed structural and functional analyses of the organic microrings and organic microplates from T. pseudonana. Proteomics analysis yielded seven proteins of unknown function (termed SiMat proteins) together with five known silica biomineralization proteins (four cingulins and one silaffin). The location of SiMat1-GFP in the insoluble organic microrings and the similarity of tyrosine- and lysine-rich functional domains identifies this protein as a new member of the cingulin protein family. Mass spectrometric analysis indicates that most of the lysine residues of cingulins and the other insoluble organic matrix proteins are post-translationally modified by short polyamine groups, which are known to enhance the silica formation activity of proteins. Studies with recombinant cingulins (rCinY2 and rCinW2) demonstrate that acidic conditions (pH 5.5) trigger the assembly of mixed cingulin aggregates that have silica formation activity. Our results suggest an important role for cingulins in the biogenesis of organic microrings and support the hypothesis that this type of insoluble organic matrix functions in biosilica morphogenesis. PMID:26710847

  3. Biochemical Composition and Assembly of Biosilica-associated Insoluble Organic Matrices from the Diatom Thalassiosira pseudonana.

    Science.gov (United States)

    Kotzsch, Alexander; Pawolski, Damian; Milentyev, Alexander; Shevchenko, Anna; Scheffel, André; Poulsen, Nicole; Shevchenko, Andrej; Kröger, Nils

    2016-03-04

    The nano- and micropatterned biosilica cell walls of diatoms are remarkable examples of biological morphogenesis and possess highly interesting material properties. Only recently has it been demonstrated that biosilica-associated organic structures with specific nanopatterns (termed insoluble organic matrices) are general components of diatom biosilica. The model diatom Thalassiosira pseudonana contains three types of insoluble organic matrices: chitin meshworks, organic microrings, and organic microplates, the latter being described in the present study for the first time. To date, little is known about the molecular composition, intracellular assembly, and biological functions of organic matrices. Here we have performed structural and functional analyses of the organic microrings and organic microplates from T. pseudonana. Proteomics analysis yielded seven proteins of unknown function (termed SiMat proteins) together with five known silica biomineralization proteins (four cingulins and one silaffin). The location of SiMat1-GFP in the insoluble organic microrings and the similarity of tyrosine- and lysine-rich functional domains identifies this protein as a new member of the cingulin protein family. Mass spectrometric analysis indicates that most of the lysine residues of cingulins and the other insoluble organic matrix proteins are post-translationally modified by short polyamine groups, which are known to enhance the silica formation activity of proteins. Studies with recombinant cingulins (rCinY2 and rCinW2) demonstrate that acidic conditions (pH 5.5) trigger the assembly of mixed cingulin aggregates that have silica formation activity. Our results suggest an important role for cingulins in the biogenesis of organic microrings and support the hypothesis that this type of insoluble organic matrix functions in biosilica morphogenesis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Surface modification of commercial seawater reverse osmosis membranes by grafting of hydrophilic monomer blended with carboxylated multiwalled carbon nanotubes

    Science.gov (United States)

    Vatanpour, Vahid; Zoqi, Naser

    2017-02-01

    In this study, modification of commercial seawater reverse osmosis membranes was carried out with simultaneous use of surface grafting and nanoparticle incorporation. Membrane grafting with a hydrophilic acrylic acid monomer and thermal initiator was used to increase membrane surface hydrophilicity. The used nanomaterial was carboxylated multiwalled carbon nanotubes (MWCNTs), which were dispersed in the grafting solution and deposited on membrane surface to reduce fouling by creating polymer brushes and hydrodynamic resistance. Effectiveness of the grafting process (formation of graft layer on membrane surface) was proved by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses. Increase of membrane surface hydrophilicity was approved with contact angle test. First, the grafting was performed on the membrane surfaces with different monomer concentrations, various contact times and several membrane curing times (three variables for optimization). The modified membranes were tested by a cross-flow setup using saline solution for permeability and rejection tests, and bovine serum albumin (BSA) solution for fouling test. The results showed that the modified membranes with 0.75 M of monomer, 3 min contact time and 80 min curing time in an oven at 50 °C presented the highest flux and lowest rejection decline related to the commercial reverse osmosis membrane. In the next step, the optimum grafting condition was selected and the nanotubes with different weight percentages were dispersed in the acrylic acid monomer solution. The membrane containing 0.25 wt% COOH-MWCNTs showed the highest fouling resistance.

  5. Solubilization of poorly water-soluble compounds using amphiphilic phospholipid polymers with different molecular architectures.

    Science.gov (United States)

    Mu, Mingwei; Konno, Tomohiro; Inoue, Yuuki; Ishihara, Kazuhiko

    2017-10-01

    To achieve stable and effective solubilization of poorly water-soluble bioactive compounds, water-soluble and amphiphilic polymers composed of hydrophilic 2-methacryloyloxyethyl phosphorylcholine (MPC) units and hydrophobic n-butyl methacrylate (BMA) units were prepared. MPC polymers having different molecular architectures, such as random-type monomer unit sequences and block-type sequences, formed polymer aggregates when they were dissolved in aqueous media. The structure of the random-type polymer aggregate was loose and flexible. On the other hand, the block-type polymer formed polymeric micelles, which were composed of very stable hydrophobic poly(BMA) cores and hydrophilic poly(MPC) shells. The solubilization of a poorly water-soluble bioactive compound, paclitaxel (PTX), in the polymer aggregates was observed, however, solubilizing efficiency and stability were strongly depended on the polymer architecture; in other words, PTX stayed in the poly(BMA) core of the polymer micelle formed by the block-type polymer even when plasma protein was present in the aqueous medium. On the other hand, when the random-type polymer was used, PTX was transferred from the polymer aggregate to the protein. We conclude that water-soluble and amphiphilic MPC polymers are good candidates as solubilizers for poorly water-soluble bioactive compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Novel polymer coatings based on plasma polymerized 2-methoxyethyl acrylate

    DEFF Research Database (Denmark)

    Wu, Zhenning; Jiang, Juan; Benter, Maike

    2008-01-01

    plasma system[4]. The system named SoftPlasma™ is equipped with unique three-phase pulsed AC voltage. Low energy plasma polymerization has almost no thermal load for sensitive polymer materials[5]. Plasma polymerized coatings are highly cross-linked, pin-hole free and provide hydrophilic or hydrophobic...... synthesized by Atom Transfer Radical Polymerization (ATRP)[3]. This enabled a surface segregation of the more hydrophilic block to the polymer/air interface and enrichment of the surface with PMEA. Here we present another way to modify a surface with this material - plasma polymerization in a low energy...... properties[4-6]. We have exploited these possibilities and prepared plasma polymerized 2-methoxyethyl acrylate (PPMEA) coatings on various polymer substrates. The PPMEA coatings were optimized using various plasma polymerization conditions and characterized by X-ray photoelectron spectroscopy...

  7. Hydrophilization of graphite using plasma above/in a solution

    Science.gov (United States)

    Hoshino, Shuhei; Kawahara, Kazuma; Takeuchi, Nozomi

    2018-01-01

    A hydrophilization method for graphite is required for applications such as conductive ink. In typical chemical oxidation methods for graphite have the problems of producing many defects in graphite and a large environmental impact. In recent years, the plasma treatment has attracted attention because of the high quality of the treated samples and the low environmental impact. In this study, we proposed an above-solution plasma treatment with a high contact probability of graphite and plasma since graphite accumulates on the solution surface due to its hydrophobicity, which we compared with a so-called solution plasma treatment. Graphite was hydrophilized via reactions with OH radicals generated by the plasma. It was confirmed that hydroxyl and carboxyl groups were modified to the graphite and the dispersibility was improved. The above-solution plasma achieved more energy-efficient hydrophilization than the solution plasma and it was possible to enhance the dispersibility by increasing the plasma–solution contact area.

  8. Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

    Directory of Open Access Journals (Sweden)

    Ladan Espandar

    2011-01-01

    Full Text Available Ladan Espandar1, Shameema Sikder2, Majid Moshirfar31Department of Ophthalmology, Tulane University, New Orleans, LA, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA; 3John A Moran Eye Center, University of Utah, Salt Lake City, UT, USAAbstract: Intraocular lens development is driven by higher patient expectations for ideal visual outcomes. The recently US Food and Drug Administration-approved Softec HD™ lens is an aspheric, hydrophilic acrylic intraocular lens (IOL. The hydrophilic design of the lens is optimized to address dysphotopsia while maintaining biocompatibility, optical clarity, resistance to damage, and resistance to biocontamination. Aspheric lenses decrease postoperative spherical aberration. The addition of the Softec lens provides clinicians with another option for IOL placement; however, randomized comparative studies of this lens to others already on the market remain to be completed.Keywords: hydrophilic acrylic intraocular lens, Softec HD intraocular lens, aspheric intraocular lens, IOL

  9. Viscous hydrophilic injection matrices for serial crystallography.

    Science.gov (United States)

    Kovácsová, Gabriela; Grünbein, Marie Luise; Kloos, Marco; Barends, Thomas R M; Schlesinger, Ramona; Heberle, Joachim; Kabsch, Wolfgang; Shoeman, Robert L; Doak, R Bruce; Schlichting, Ilme

    2017-07-01

    Serial (femtosecond) crystallography at synchrotron and X-ray free-electron laser (XFEL) sources distributes the absorbed radiation dose over all crystals used for data collection and therefore allows measurement of radiation damage prone systems, including the use of microcrystals for room-temperature measurements. Serial crystallography relies on fast and efficient exchange of crystals upon X-ray exposure, which can be achieved using a variety of methods, including various injection techniques. The latter vary significantly in their flow rates - gas dynamic virtual nozzle based injectors provide very thin fast-flowing jets, whereas high-viscosity extrusion injectors produce much thicker streams with flow rates two to three orders of magnitude lower. High-viscosity extrusion results in much lower sample consumption, as its sample delivery speed is commensurate both with typical XFEL repetition rates and with data acquisition rates at synchrotron sources. An obvious viscous injection medium is lipidic cubic phase (LCP) as it is used for in meso membrane protein crystallization. However, LCP has limited compatibility with many crystallization conditions. While a few other viscous media have been described in the literature, there is an ongoing need to identify additional injection media for crystal embedding. Critical attributes are reliable injection properties and a broad chemical compatibility to accommodate samples as heterogeneous and sensitive as protein crystals. Here, the use of two novel hydro-gels as viscous injection matrices is described, namely sodium carb-oxy-methyl cellulose and the thermo-reversible block polymer Pluronic F-127. Both are compatible with various crystallization conditions and yield acceptable X-ray background. The stability and velocity of the extruded stream were also analysed and the dependence of the stream velocity on the flow rate was measured. In contrast with previously characterized injection media, both new matrices afford

  10. Viscous hydrophilic injection matrices for serial crystallography

    Directory of Open Access Journals (Sweden)

    Gabriela Kovácsová

    2017-07-01

    Full Text Available Serial (femtosecond crystallography at synchrotron and X-ray free-electron laser (XFEL sources distributes the absorbed radiation dose over all crystals used for data collection and therefore allows measurement of radiation damage prone systems, including the use of microcrystals for room-temperature measurements. Serial crystallography relies on fast and efficient exchange of crystals upon X-ray exposure, which can be achieved using a variety of methods, including various injection techniques. The latter vary significantly in their flow rates – gas dynamic virtual nozzle based injectors provide very thin fast-flowing jets, whereas high-viscosity extrusion injectors produce much thicker streams with flow rates two to three orders of magnitude lower. High-viscosity extrusion results in much lower sample consumption, as its sample delivery speed is commensurate both with typical XFEL repetition rates and with data acquisition rates at synchrotron sources. An obvious viscous injection medium is lipidic cubic phase (LCP as it is used for in meso membrane protein crystallization. However, LCP has limited compatibility with many crystallization conditions. While a few other viscous media have been described in the literature, there is an ongoing need to identify additional injection media for crystal embedding. Critical attributes are reliable injection properties and a broad chemical compatibility to accommodate samples as heterogeneous and sensitive as protein crystals. Here, the use of two novel hydrogels as viscous injection matrices is described, namely sodium carboxymethyl cellulose and the thermo-reversible block polymer Pluronic F-127. Both are compatible with various crystallization conditions and yield acceptable X-ray background. The stability and velocity of the extruded stream were also analysed and the dependence of the stream velocity on the flow rate was measured. In contrast with previously characterized injection media, both new

  11. Normally Oriented Adhesion versus Friction Forces in Bacterial Adhesion to Polymer-Brush Functionalized Surfaces Under Fluid Flow

    NARCIS (Netherlands)

    Swartjes, Jan J. T. M.; Veeregowda, Deepak H.; van der Mei, Henny C.; Busscher, Henk J.; Sharma, Prashant K.

    2014-01-01

    Bacterial adhesion is problematic in many diverse applications. Coatings of hydrophilic polymer chains in a brush configuration reduce bacterial adhesion by orders of magnitude, but not to zero. Here, the mechanism by which polymer-brush functionalized surfaces reduce bacterial adhesion from a

  12. Fabrication of Polymer Solar Cells Using Aqueous Processing for All Layers Including the Metal Back Electrode

    DEFF Research Database (Denmark)

    Søndergaard, Roar; Helgesen, Martin; Jørgensen, Mikkel

    2011-01-01

    The challenges of printing all layers in polymer solar cells from aqueous solution are met by design of inks for the electron-, hole-, active-, and metallic back electrode-layers. The conversion of each layer to an insoluble state after printing enables multilayer formation from the same solvent...

  13. Surface modification of commercial seawater reverse osmosis membranes by grafting of hydrophilic monomer blended with carboxylated multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Vatanpour, Vahid, E-mail: vahidvatanpour@khu.ac.ir; Zoqi, Naser

    2017-02-28

    Highlights: • A commercial PA RO membrane was modified by grafting of hydrophilic acrylic acid. • COOH-MWCNTs were mixed in grafting layer to increase permeability and antifouling. • However, more increase of CNTs caused in reduction of flux of the membranes. • Effect of acrylic acid amount, contact time and curing time was optimized. - Abstract: In this study, modification of commercial seawater reverse osmosis membranes was carried out with simultaneous use of surface grafting and nanoparticle incorporation. Membrane grafting with a hydrophilic acrylic acid monomer and thermal initiator was used to increase membrane surface hydrophilicity. The used nanomaterial was carboxylated multiwalled carbon nanotubes (MWCNTs), which were dispersed in the grafting solution and deposited on membrane surface to reduce fouling by creating polymer brushes and hydrodynamic resistance. Effectiveness of the grafting process (formation of graft layer on membrane surface) was proved by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses. Increase of membrane surface hydrophilicity was approved with contact angle test. First, the grafting was performed on the membrane surfaces with different monomer concentrations, various contact times and several membrane curing times (three variables for optimization). The modified membranes were tested by a cross-flow setup using saline solution for permeability and rejection tests, and bovine serum albumin (BSA) solution for fouling test. The results showed that the modified membranes with 0.75 M of monomer, 3 min contact time and 80 min curing time in an oven at 50 °C presented the highest flux and lowest rejection decline related to the commercial reverse osmosis membrane. In the next step, the optimum grafting condition was selected and the nanotubes with different weight percentages were dispersed in the acrylic acid monomer solution. The membrane containing 0.25 wt% COOH-MWCNTs showed the

  14. Microporous polymer films and methods of their production

    Science.gov (United States)

    Aubert, James H.

    1995-01-01

    A process for producing thin microporous polymeric films for a variety of uses. The process utilizes a dense gas (liquified gas or supercritical fluid) selected to combine with a solvent-containing polymeric film so that the solvent is dissolved in the dense gas, the polymer is substantially insoluble in the dense gas, and two phases are formed. A microporous film is obtained by removal of a dense gas-solvent phase.

  15. Dynamic encapsulation of hydrophilic nisin in hydrophobic poly (lactic acid) particles with controlled morphology by a single emulsion process.

    Science.gov (United States)

    Ji, Shaowen; Lu, Jue; Liu, Zhiguo; Srivastava, Devesh; Song, Anna; Liu, Yan; Lee, Ilsoon

    2014-06-01

    Hydrophilic nisin-loaded hydrophobic poly (lactic acid) (PLA) particles with controlled size and shape were successfully produced utilizing a one-step single emulsification method. Preliminary shear stress and temperature tests showed that there was no significant loss in the nisin inhibition activity during this process. PLA/nisin composite particles were prepared into solid nanocomposite spheres (50-200 nm) or hollow microcomposite spheres (1-5 μm) under the operative conditions developed in our previous study, in which the hydrophilic nisin in the aqueous phase solution could be entrapped in the hydrophobic polymer in the emulsification process generating either single or multiple emulsions. The incorporation of nisin in PLA had little effect on key processing conditions, which allows the dynamic control of the morphology and property of resulting particles. Microscopic and surface analyses suggested that nisin was dispersed uniformly inside the polymer matrix and adsorbed on the particle surface. The encapsulation amount and efficiency were enhanced with the increase in nisin loading in the aqueous solution. Unique reversible control of particle size and shape by this process was successfully applied in the nisin encapsulation. Alternating temperature in the repeating emulsification steps improved the encapsulation efficiency while generated particles in desired size and shape. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Hydrophilic thermoplastic polyurethanes for the manufacturing of highly dosed oral sustained release matrices via hot melt extrusion and injection molding.

    Science.gov (United States)

    Verstraete, G; Van Renterghem, J; Van Bockstal, P J; Kasmi, S; De Geest, B G; De Beer, T; Remon, J P; Vervaet, C

    2016-06-15

    Hydrophilic aliphatic thermoplastic polyurethane (Tecophilic™ grades) matrices for high drug loaded oral sustained release dosage forms were formulated via hot melt extrusion/injection molding (HME/IM). Drugs with different aqueous solubility (diprophylline, theophylline and acetaminophen) were processed and their influence on the release kinetics was investigated. Moreover, the effect of Tecophilic™ grade, HME/IM process temperature, extrusion speed, drug load, injection pressure and post-injection pressure on in vitro release kinetics was evaluated for all model drugs. (1)H NMR spectroscopy indicated that all grades have different soft segment/hard segment ratios, allowing different water uptake capacities and thus different release kinetics. Processing temperature of the different Tecophilic™ grades was successfully predicted by using SEC and rheology. Tecophilic™ grades SP60D60, SP93A100 and TG2000 had a lower processing temperature than other grades and were further evaluated for the production of IM tablets. During HME/IM drug loads up to 70% (w/w) were achieved. In addition, Raman mapping and (M)DSC results confirmed the homogenous distribution of mainly crystalline API in all polymer matrices. Besides, hydrophilic TPU based formulations allowed complete and sustained release kinetics without using release modifiers. As release kinetics were mainly affected by drug load and the length of the PEO soft segment, this polymer platform offers a versatile formulation strategy to adjust the release rate of drugs with different aqueous solubility. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. A Facile Strategy for Catalyst Separation and Recycling Suitable for ATRP of Hydrophilic Monomers Using a Macroligand.

    Science.gov (United States)

    Jiang, Xiaowu; Wu, Jian; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2016-01-01

    How to simply and efficiently separate and recycle catalyst has still been a constraint for the wide application of atom transfer radical polymerization (ATRP), especially for the polymerization systems with hydrophilic monomers because the polar functional groups may coordinate with transition metal salts, resulting in abundant catalyst residual in the resultant water-soluble polymers. In order to overcome this problem, a latent-biphasic system is developed, which can be successfully used for ATRP catalyst separation and recycling in situ for various kinds of hydrophilic monomers for the first time, such as poly(ethylene glycol) monomethyl ether methacrylate (PEGMA), 2-hydroxyethyl methacrylate (HEMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), N,N-dimethyl acrylamide (DMA), and N-isopropylacrylamide (NIPAM). Herein, random copolymer of octadecyl acrylate (OA), MA-Ln (2-(bis(pyridin-2-ylmethyl)amino)ethyl acrylate), and POA-ran-P(MA-Ln) is designed as the macroligand, and heptane/ethanol is selected as the biphasic solvent. Copper(II) bromide (CuBr2 ) is employed as the catalyst, PEG-bound 2-bromo-2-methylpropanoate (PEG350 -Br) as the water-soluble ATRP initiator and 2,2'-azobis(isobutyronitrile) (AIBN) as the azo-initiator to establish an ICAR (initiators for continuous activator regeneration) ATRP system. Importantly, well-defined water-soluble polymers are obtained even though the recyclable catalyst is used for sixth times. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Solid state interaction of raloxifene HCl with different hydrophilic carriers during co-grinding and its effect on dissolution rate.

    Science.gov (United States)

    Garg, Anuj; Singh, S; Rao, V U; Bindu, K; Balasubramaniam, J

    2009-04-01

    This study investigated the effects of different classes of hydrophilic carriers (poly vinyl pyrrolidones [PVPs] [Plasdone K-25 and Plasdone S-630], cellulosic polymers [hydroxypropyl methyl cellulose and hydroxy propyl cellulose], and Sodium Alginate) on the solid state and dissolution rate of Raloxifene hydrochloride (R-HCl). Solid state characterizations of co-ground mixtures and physical mixtures in 1:1 and 1:2 ratios of drug to polymer were performed by employing laser diffractometer for particle size and differential scanning calorimetry (DSC) for solid state interactions. The results of particle size studies showed that only co-grinding with PVPs was more effective in the reduction of particle size than the milling of drug alone. DSC study indicated that the crystalline nature of the drug was reduced after co-grinding with PVPs when compared with their corresponding physical mixtures. The hydrophilic carriers other than PVPs did not reduce the crystalline nature of the drug significantly. X-ray diffraction and scanning electron microscopy were carried out for selected batches to confirm DSC results. Significant enhancement in dissolution rate and extent was observed with co-ground mixtures of drug and PVPs. Plasdone S-630 was found to be a better carrier for R-HCl in terms of achieving improvement in dissolution. In vitro dissolution data can be described by Hixson-Crowell model, indicating the drug release mechanism predominated by erosion.

  19. Polymer Electrolytes

    Science.gov (United States)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  20. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  1. 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.

  2. A study on the release mechanism of drugs from hydrophilic partially coated perforated matrices.

    Science.gov (United States)

    Sangalli, Maria Edvige; Maroni, Alessandra; Zema, Lucia; Cerea, Matteo; Conte, Ubaldo; Gazzaniga, Andrea

    2003-09-01

    Partially coated perforated systems (PCPS) based on low-viscosity hydroxypropyl methylcellulose (HPMC) as the polymeric material were formerly designed, prepared and evaluated in terms of in vitro behaviour. These systems proved to afford the pursued linear release with model drugs (metoprolol tartrate and benfluorex) of different solubility. To the aim of exploring the mechanisms concurring in the definition of zero-order kinetics, studies of drug release, polymer dissolution and medium penetration were performed on PCPS and constant release area systems (CRAS). According to the obtained results, PCPS release kinetics has to be mainly attributed to the progressive outward erosion of the core and to the related variation of the release area. The special geometry of the system, in fact, involves a gradual increase in the release surface, which allows the diffusional path lengthening to be offset. By properly selecting the shape and dimensions of the device as well as the physico-chemical characteristics of the hydrophilic polymer, the advantage of a zero-order release kinetics with programmable rate can be achieved.

  3. Gas Bubbles Stabilized by Janus Particles with Varying Hydrophilic-Hydrophobic Surface Characteristics.

    Science.gov (United States)

    Fujii, Syuji; Yokoyama, Yuichi; Nakayama, Saori; Ito, Masanori; Yusa, Shin-Ichi; Nakamura, Yoshinobu

    2018-01-23

    Micrometer-sized polymer-grafted gold-silica (Au-SiO2) Janus particles were fabricated by vacuum evaporation followed by polymer grafting. The Janus particle diameter, diameter distribution, morphology, surface chemistry, and water wettability were characterized by optical microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and contact angle measurements. The optical microscopy results showed that the polystyrene (PS)-grafted Au-SiO2 Janus particles exhibited monolayer adsorption at the air-water interface and could stabilize bubbles, preventing their coalescence for more than 1 month. The hydrophobic PS-grafted Au and hydrophilic SiO2 surfaces were exposed to the air and water phases, respectively. Bare Au-SiO2 and poly(2-(perfluorobutyl)ethyl methacrylate) (PPFBEM)-grafted Au-SiO2 Janus particles could also stabilize bubbles for up to 2 weeks. By contrast, bare silica particles did not stabilize bubbles and were dispersed in water. The bubbles that formed in the PS-grafted Janus particle system were more stable than those formed in the bare Au-SiO2 Janus particles, PPFBEM-grafted Au-SiO2 Janus particles, and SiO2 particle systems because of the high adsorption energy of the PS-grafted particles at the air-water interface.

  4. Neutral hydrophilic coatings for capillary electrophoresis prepared by controlled radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Fabián H.; Gómez, Jorge E.; Espinal, José H.; Sandoval, Junior E., E-mail: junior.sandoval@correounivalle.edu.co

    2016-12-15

    In the present study, porous silica particles as well as impervious fused-silica wafers and capillary tubes were modified with hydrophilic polymers (hydroxylated polyacrylamides and polyacrylates), using a surface-confined grafting procedure based on atom transfer radical polymerization (ATRP) which was also surface-initiated from α-bromoisobutyryl groups. Initiator immobilization was achieved by hydrosilylation of allyl alcohol on hydride silica followed by esterification of the resulting propanol-bonded surface with α-bromoisobutyryl bromide. Elemental analysis, IR and NMR spectroscopies on silica micro-particles, atomic force microscopy, ellipsometry and profilometry on fused-silica wafers, as well as CE on fused-silica tubes were used to characterize the chemically modified silica substrate at different stages. We studied the effect of monomer concentration as well as cross-linker on the ability of the polymer film to reduce electroosmosis and to prevent protein adsorption (i. e., its non-fouling capabilities) and found that the former was rather insensitive to both parameters. Surface deactivation towards adsorption was somewhat more susceptible to monomer concentration and appeared also to be favored by a low concentration of the cross-linker. The results show that hydrophilic polyacrylamide and polyacrylate coatings of controlled thickness can be prepared by ATRP under very mild polymerization conditions (aqueous solvent, room temperature and short reaction times) and that the coated capillary tubes exhibit high efficiencies for protein separations (0.3–0.6 million theoretical plates per meter) as well as long-term hydrolytic stability under the inherently harsh conditions of capillary isoelectric focusing. Additionally, there was no adsorption of lysozyme on the coated surface as indicated by a complete recovery of the basic enzyme. Furthermore, since polymerization is confined to the inner capillary surface, simple precautions (e.g., solution

  5. The influence of evaporation on long-wavelength instabilities in liquid layer with insoluble surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Mikishev, Alexander [Department of Physics, Sam Houston State University, Huntsville, TX 77341 (United States); A Nepomnyashchy, Alexander, E-mail: amik@shsu.edu, E-mail: nepom@technion.ac.il [Department of Mathematics, Technion—Israel Institute of Technology, Haifa 32000 (Israel)

    2014-08-01

    We investigate the long-wavelength Marangoni instability in an evaporating horizontal liquid layer with insoluble surfactant absorbed on the free deformable surface. The insoluble surfactant hinders the evaporation of the liquid into a vapor. The mass flux depends on the difference between the actual surface temperature and the equilibrium one. Different kinetics limited regimes of evaporation are considered. Density, viscosity, and thermal conductivity of the vapor are smaller than those of the liquid, and a one-sided model is applied. The layer is subjected to a heat flux at its bottom. We assume a small heat transfer coefficient at the interface. The linear stability analysis of this system for different values of kinetic resistance parameter is performed. Instability thresholds are determined and critical Marangoni numbers for monotonic, as well as for oscillatory mode, are found. (paper)

  6. Kinetic model for microbial uptake of insoluble solid-state substrate.

    Science.gov (United States)

    Huang, S Y; Chou, M S

    1990-03-15

    A kinetic model for anaerobic digestion of insoluble solid-state substrates was developed. Rate equations for cell growth and substrate consumption were derived based on the assumption that the microorganisms assimilate the substrate mainly at the point of contact where they grow. The model emphasizes effects of substrate particle size, organic loading, and cell concentration on the rates of cell growth and substrate utilization. Batch digestion of a stearic acid emulsion with a mean particle size of 2.0 microm and a biological sludge was conducted at 30 and 37 degrees C to verify the proposed model. Agreement between the experimental and calculated results indicated the validity of the model for describing the microbial degradation of insoluble solid-state substrates. Further examination of the model revealed that with low cell substrate affinity or at low cell concentration, it coincided with a Michaelis-Menten type kinetics in which the effect of particle size was taken into consideration.

  7. An amperometric enzyme biosensor for real-time measurements of cellobiohydrolase activity on insoluble cellulose

    DEFF Research Database (Denmark)

    Cruys-Bagger, Nicolaj; Guilin, Ren; Tatsumi, Hirosuke

    2012-01-01

    An amperometric enzyme biosensor for continuous detection of cellobiose has been implemented as an enzyme assay for cellulases. We show that the initial kinetics for cellobiohydrolase I, Cel7A from Trichoderma reesei, acting on different types of cellulose substrates, semi-crystalline and amorphous......) and this provided experimental access to the transient kinetics of cellobiohydrolases acting on insoluble cellulose. The response from the CDH-biosensor during enzymatic hydrolysis was corrected for the specificity of PcCDH for the β-anomer of cello-oligosaccharides and the approach were validated against HPLC....... It is suggested that quantitative, real-time data on pure insoluble cellulose substrates will be useful in attempts to probe the molecular mechanism underlying enzymatic hydrolysis of cellulose...

  8. Removal of metals and water-insoluble materials from desalter emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, S.K.; Mosby, J.F.; Treadman, J.E. II.

    1993-06-15

    A process for removing metals and insoluble materials from crude oil is described comprising the steps of: blending crude oil with water and desalting chemicals; charging the oil blend to a desalting chamber and passing it through an electrical field whereby agglomeration of suspended insoluble materials occurs and layers of clean oil, brine and oil-brine interface emulsion are formed; withdrawing the oil and brine; measuring the volume of the emulsion layer; withdrawing a portion of the emulsion layer; blending the withdrawn emulsion with up to 2 volumes of aromatic-rich hydrocarbon containing at least 20% aromatics by volume; maintaining the blend at a temperature of 100 to 300 F and a positive pressure; and subjecting the blend to a force of at least about 500 g, whereby oil free of at least 90% of suspended particulates and water results.

  9. Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells.

    Science.gov (United States)

    Nalluri, Sandeep M; Krishnan, G Rajesh; Cheah, Calvin; Arzumand, Ayesha; Yuan, Yuan; Richardson, Caley A; Yang, Shuying; Sarkar, Debanjan

    2015-09-01

    Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell-matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell-cell and cell-matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell-matrix interaction, and cell-cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Adsorption of trypsin on hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Koutsopoulos, Sotirios; Patzsch, Katja; Bosker, Wouter T. E.; Norde, Willem

    2007-01-01

    The adsorption of trypsin onto polystyrene and silica surfaces was investigated by reflectometry, spectroscopic methods, and atomic force microscopy (AFM). The affinity of trypsin for the hydrophobic polystyrene surface was higher than that for the hydrophilic silica surface, but steady-state

  11. Self-generation of colligative properties at hydrophilic surfaces

    OpenAIRE

    Chaplin, Martin

    2012-01-01

    The generally accepted view of osmotic pressure is that it is a colligative property, along with freezing point depression, boiling point elevation and vapour pressure lowering. These properties ideally depend on the concentration of dissolved solute molecules. Osmotic pressure, however, is also generated, without any solute, at hydrophilic surfaces. Here is presented a rationale and explanation for this phenomenon.

  12. 21 CFR 872.3300 - Hydrophilic resin coating for dentures.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydrophilic resin coating for dentures. 872.3300 Section 872.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... into the patient's mouth to improve denture retention and comfort. (b) Classification. Class II. ...

  13. Development of breathable hydrophobic/hydrophilic functional textiles

    NARCIS (Netherlands)

    Agrawal, P. (Pramod); Brink, G.J. (Ger)

    2013-01-01

    The proposed bi-functional protective structure intended to have hydrophilic interior towards the skin surface and hydrophobic exterior for protection, ensuring fast transfer of moisture between body and external environment. The sandwich structure is prepared using 100% wool jersey and varieties of

  14. Hydroglyphics: Demonstration of Selective Wetting on Hydrophilic and Hydrophobic Surfaces

    Science.gov (United States)

    Kim, Philseok; Alvarenga, Jack; Aizenberg, Joanna; Sleeper, Raymond S.

    2013-01-01

    A visual demonstration of the difference between hydrophilic and hydrophobic surfaces has been developed. It involves placing a shadow mask on an optically clear hydrophobic plastic dish, corona treating the surface with a modified Tesla coil, removing the shadow mask, and visualizing the otherwise invisible message or pattern by applying water,…

  15. Autoactivation of blood factor XII at hydrophilic and hydrophobic surfaces.

    Science.gov (United States)

    Zhuo, Rui; Siedlecki, Christopher A; Vogler, Erwin A

    2006-08-01

    Contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution is shown not to be specific for anionic hydrophilic procoagulants as proposed by the accepted biochemistry of surface activation. Rather, FXII activation in the presence of plasma proteins leads to an apparent specificity for hydrophilic surfaces that is actually due to a relative diminution of the FXII-->FXIIa reaction at hydrophobic surfaces. FXII activation in neat-buffer solution was effectively instantaneous upon contact with either hydrophilic (fully water-wettable clean glass) or hydrophobic (poorly water-wettable silanized glass) procoagulant particles, with greater FXIIa yield obtained by activation with hydrophobic procoagulants. In sharp contrast, both activation rate and yield was found to be significantly attenuated at hydrophobic surfaces in the presence of plasma proteins. Putative FXIIa produced by surface activation with both hydrophilic and hydrophobic procoagulants was shown to hydrolyze blood factor XI (FXI) to the activated form FXIa (FXIFXIIa-->FXIa) that causes FXI-deficient plasma to rapidly coagulate.

  16. Aggregation of amyloidogenic peptides near hydrophobic and hydrophilic surfaces.

    Science.gov (United States)

    Brovchenko, Ivan; Singh, Gurpreet; Winter, Roland

    2009-07-21

    The general effect of surface hydrophobicity/hydrophilicity on the aggregation of peptides is studied by simulations of oversaturated aqueous solutions of hydrophobic and hydrophilic amyloidogenic peptides. Peptide aggregation was studied in bulk solution, in solutions confined between hydrophobic boundaries (smooth planar paraffin-like surfaces and liquid-vapor interfaces) and in solutions confined between hydrophilic surfaces (smooth planar silica-like surfaces). Aggregation of hydrophobic peptides strongly enhances due to the confinement between hydrophobic surfaces with all peptides adsorbed at the boundaries and aligned predominantly parallel to them. In the other three cases considered, the peptides are repelled from the walls and do not reveal orientational ordering with respect to the surface. The degree of peptide aggregation in these cases is only slightly affected by the confinement (it is enhanced for hydrophobic peptides and decreased for hydrophilic peptides). Our results show that even a single environmental factor such as water-mediated peptide-surface interaction has a drastic effect on the degree and character of peptide aggregation. A wide diversity of possible scenarios can be expected when specific peptide-surface interactions are additionally taken into account.

  17. Bacterial adhesion to surface hydrophilic and hydrophobic contact lenses

    NARCIS (Netherlands)

    Bruinsma, GM; van der Mei, HC; Busscher, HJ

    2001-01-01

    The aim of this paper was to determine the adhesion of two physico-chemically characterized bacterial strains to a surface hydrophilic (CL A, water contact angle 57 degrees) and hydrophobic (CL B, water contact angle 106 degrees) hydrogel contact lens (CL) with and without an adsorbed tear film in a

  18. Presence of insoluble Tau following rotenone exposure ameliorates basic pathways associated with neurodegeneration

    Directory of Open Access Journals (Sweden)

    Rodrigo S. Chaves

    2016-12-01

    Full Text Available Protein aggregation is an important feature of neurodegenerative disorders. In Alzheimer's disease (AD protein aggregates are composed of hyperphosphorylated Tau and amyloid beta peptide (Aβ. Despite the involvement and identification of the molecular composition of these aggregates, their role in AD pathophysiology is not fully understood. However, depositions of these insoluble aggregates are typically reported as pathogenic and toxic for cell homeostasis. New evidences suggest that the deposition of these aggregates is a protective mechanism that preserves cell from toxic insults associated with the early stages of neurodegenerative diseases. To better understand the biological role of the protein aggregation with regard its effects in cellular homeostasis, the present study investigated the role of insoluble Tau and Tau aggregates on crucial cellular parameters such as redox homeostasis, proteasome activity and autophagy in hippocampal cell cultures and hippocampus of aged Lewis rats using a rotenone-induced aggregation model. Neurons were exposed to rotenone in different concentrations and exposure times aiming to determine the interval required for Tau aggregation. Our experimental design allowed us to demonstrate that rotenone exposure induces Tau hyperphosphorylation and aggregation in a concentration and time-dependent manner. Oxidative stress triggered by rotenone exposure was observed with the absence of Tau aggregates and was reduced or absent when Tau aggregates were present. This reduction of oxidative stress along with the presence of insoluble Tau was independent of alterations in antioxidant enzymes activities or cell death. In addition, rotenone induced oxidative stress was mainly associated with decrease in proteasome activity and autophagy flux. Conversely, when insoluble Tau appeared, autophagy turns to be overactivated while proteasome activity remained low. Our studies significantly advance the understanding that Tau

  19. A new method for the analysis of soluble and insoluble oxalate in pulp and paper matrices

    CSIR Research Space (South Africa)

    Sithole, Bruce

    2013-11-01

    Full Text Available Engineering Keywords: Oxalate, ion chromatography, methanesulphonic acid, calcium oxalate URL: http://mc.manuscriptcentral.com/lwct Email: John.Kadla@ubc.ca Journal of Wood Chemistry and Technology For Peer Review Only A new method for the analysis... the effectiveness of various strategies to control oxalate scale deposition. KEYWORDS Oxalate, soluble, insoluble, methanesulphonic acid, ion chromatography, pulp and paper Page 1 of 33 URL: http://mc.manuscriptcentral.com/lwct Email: John...

  20. Branched polymers on branched polymers

    OpenAIRE

    Durhuus, Bergfinnur; Jonsson, Thordur

    1996-01-01

    We study an ensemble of branched polymers which are embedded on other branched polymers. This is a toy model which allows us to study explicitly the reaction of a statistical system on an underlying geometrical structure, a problem of interest in the study of the interaction of matter and quantized gravity. We find a phase transition at which the embedded polymers begin to cover the basis polymers. At the phase transition point the susceptibility exponent $\\gamma$ takes the value 3/4 and the ...

  1. Effect of homogenization and ultrasonication on the physical properties of insoluble wheat bran fibres

    Science.gov (United States)

    Hu, Ran; Zhang, Min; Adhikari, Benu; Liu, Yaping

    2015-10-01

    Wheat bran is rich in dietary fibre and its annual output is abundant, but underutilized. Insoluble dietary fibre often influences food quality negatively; therefore, how to improve the physical and chemical properties of insoluble dietary fibre of wheat bran for post processing is a challenge. Insoluble dietary fibre was obtained from wheat bran and micronized using high-pressure homogenization, high-intensity sonication, and a combination of these two methods. The high-pressure homogenization and high-pressure homogenization+high-intensity sonication treatments significantly (pproperties by high-intensity sonication alone was marginal. In most cases, the high-pressure homogenization process was as good as the high-pressure homogenization+high-intensity sonication process in improving the above-mentioned properties; hence, the contribution of high-`intensity sonication in the high-pressure homogenization+high-intensity sonication process was minimal. The best results show that the minimum particle size of wheat bran can reach 9 μm, and the solubility, swelling, water-holding, oil-holding, cation exchange capacities change significantly.

  2. Improvement of thermostability and activity of Trichoderma reesei endo-xylanase Xyn III on insoluble substrates.

    Science.gov (United States)

    Matsuzawa, Tomohiko; Kaneko, Satoshi; Yaoi, Katsuro

    2016-09-01

    Trichoderma reesei Xyn III, an endo-β-1,4-xylanase belonging to glycoside hydrolase family 10 (GH10), is vital for the saccharification of xylans in plant biomass. However, its enzymatic thermostability and hydrolytic activity on insoluble substrates are low. To overcome these difficulties, the thermostability of Xyn III was improved using random mutagenesis and directed evolution, and its hydrolytic activity on insoluble substrates was improved by creating a chimeric protein. In the screening of thermostable Xyn III mutants from a random mutagenesis library, we identified two amino acid residues, Gln286 and Asn340, which are important for the thermostability of Xyn III. The Xyn III Gln286Ala/Asn340Tyr mutant showed xylanase activity even after heat treatment at 60 °C for 30 min or 50 °C for 96 h, indicating a dramatic enhancement in thermostability. In addition, we found that the addition of a xylan-binding domain (XBD) to the C-terminal of Xyn III improved its hydrolytic activity on insoluble xylan.

  3. Insoluble drug delivery strategies: review of recent advances and business prospects

    Directory of Open Access Journals (Sweden)

    Sandeep Kalepu

    2015-09-01

    Full Text Available The emerging trends in the combinatorial chemistry and drug design have led to the development of drug candidates with greater lipophilicity, high molecular weight and poor water solubility. Majority of the failures in new drug development have been attributed to poor water solubility of the drug. Issues associated with poor solubility can lead to low bioavailability resulting in suboptimal drug delivery. About 40% of drugs with market approval and nearly 90% of molecules in the discovery pipeline are poorly water-soluble. With the advent of various insoluble drug delivery technologies, the challenge to formulate poorly water soluble drugs could be achieved. Numerous drugs associated with poor solubility and low bioavailabilities have been formulated into successful drug products. Several marketed drugs were reformulated to improve efficacy, safety and patient compliance. In order to gain marketing exclusivity and patent protection for such products, revitalization of poorly soluble drugs using insoluble drug delivery technologies have been successfully adopted by many pharmaceutical companies. This review covers the recent advances in the field of insoluble drug delivery and business prospects.

  4. Insoluble drug delivery strategies: review of recent advances and business prospects.

    Science.gov (United States)

    Kalepu, Sandeep; Nekkanti, Vijaykumar

    2015-09-01

    The emerging trends in the combinatorial chemistry and drug design have led to the development of drug candidates with greater lipophilicity, high molecular weight and poor water solubility. Majority of the failures in new drug development have been attributed to poor water solubility of the drug. Issues associated with poor solubility can lead to low bioavailability resulting in suboptimal drug delivery. About 40% of drugs with market approval and nearly 90% of molecules in the discovery pipeline are poorly water-soluble. With the advent of various insoluble drug delivery technologies, the challenge to formulate poorly water soluble drugs could be achieved. Numerous drugs associated with poor solubility and low bioavailabilities have been formulated into successful drug products. Several marketed drugs were reformulated to improve efficacy, safety and patient compliance. In order to gain marketing exclusivity and patent protection for such products, revitalization of poorly soluble drugs using insoluble drug delivery technologies have been successfully adopted by many pharmaceutical companies. This review covers the recent advances in the field of insoluble drug delivery and business prospects.

  5. Conducting Polymers

    Indian Academy of Sciences (India)

    potential of the monomer would be less than that of the dimer, which would in turn be less than that of the polymer. Hence, the polymer generated by this oxidative .... glucose and galactose biosensors based on a silicon chip employing polypyrrole have in fact been developed by several companies. These types of sensors ...

  6. Conducting Polymers

    Indian Academy of Sciences (India)

    polymer backbone), exhibit semiconducting behavior. The discovery of dopingl led to a further dramatic increase in the conductivity of such conjugated polymers to values as ..... CERF's Comments on Modem Science. • If it's incomprehensible, it's mathematics. • If it doesn't make sense, it's either economics or psychology.

  7. 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…

  8. Characterization of insoluble macromolecular Sn(II) complex and its application to the [sup 99m]Tc labeling of human serum albumin-bearing mercapto groups

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, M.; Terahara, T.; Ikeda, R. (Kumamoto Univ. (Japan). Faculty of Pharmaceutical Sciences) (and others)

    1994-01-01

    A chelating ion exchange resin containing aminophosphonic acid groups was used as a polymer matrix for the preparation of an insoluble macromolecular Sn(II)(R-Sn) complex. Sn(II), which strongly bound to the surface of the polymer matrix by chelation, retained the ability to reduce [sup 99m]Tc in the R-Sn complex. Human serum albumin-bearing-mercapto groups (HMA) was labeled with [sup 99m]Tc at Ph 2-3 using the R-Sn complex or SnCl[sub 2] as reducing agent. The [sup 99m]Tc-HMA labeled with the R-Sn complex resulted in a higher sustained level of radioactivity in the blood of mice than the [sup 99m]Tc-HMA labeled with SnCl[sub 2]. These results suggest that the use of the R-Sn complex minimized Sn(II) contamination of the [sup 99m]Tc labeling solution and can be used effectively as a reducing agent for [sup 99m]Tc labeling of proteins containing sulfhydryl groups. (author).

  9. Mesoscopic Simulations of the Phase Behavior of Aqueous EO 19 PO 29 EO 19 Solutions Confined and Sheared by Hydrophobic and Hydrophilic Surfaces

    KAUST Repository

    Liu, Hongyi

    2012-01-25

    The MesoDyn method is used to investigate associative structures in aqueous solution of a nonionic triblock copolymer consisting of poly(propylene oxide) capped on both ends with poly(ethylene oxide) chains. The effect of adsorbing (hydrophobic) and nonadsorbing (hydrophilic) solid surfaces in contact with aqueous solutions of the polymer is elucidated. The macromolecules form self-assembled structures in solution. Confinement under shear forces is investigated in terms of interfacial behavior and association. The formation of micelles under confinement between hydrophilic surfaces occurs faster than in bulk aqueous solution while layered structures assemble when the polymers are confined between hydrophobic surfaces. Micelles are deformed under shear rates of 1 μs -1 and eventually break to form persistent, adsorbed layered structures. As a result, surface damage under frictional forces is prevented. Overall, this study indicates that aqueous triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (Pluronics, EO mPO nEO m) act as a boundary lubricant for hydrophobic surfaces but not for hydrophilic ones. © 2011 American Chemical Society.

  10. Ultrasound scattering from silica fume clusters: in-line shear flow dynamics of hydrophilic or partially hydrophobic silica fume fillers in melts of non-polar polymeric systems

    Science.gov (United States)

    Haïder, Leïla; Tatibouët, Jacques; Ferry, Laurent

    2008-02-01

    Shear flow dynamics of fractal aggregates are investigated by ultrasound scattering to study shear induced disruption processes of hydrophilic polydisperse silica fume fillers in melts of non-polar polymeric systems (polypropylene). A rheo-acoustical model in the low frequency scattering regime only involving structural parameters is proposed. Flow-dependent changes of the ultrasound scattering power per unit of volume from hydrophilic silica fume aggregates during extrusion are analyzed in the frame of the proposed rheo-acoustical model. In a second part, equilibrium structures of polymer coated silica fume fillers are investigated to elucidate the coupled intra- and inter-filler interactions. Surface chemistry of silica fume fillers was modified by grafting amphiphilic molecules with the same hydrophobic tail (long alkyl chains) and various hydrophilic polar heads (amine, carboxylic acid or hydroxyl groups) to obtain a range of hydrophobic fumed silica units. The effects of the surface layer of tethered chains and the extent of the coating level in a non-polar liquid dispersion are analyzed within the framework of the mismatch in chemical nature or solubility parameters between grafted chains and continuous polymer phase. Lastly, the ability of the ultrasound scattering technique to give a quantitative estimate of the critical disaggregation shear stress mainly representative of the particle surface adhesive energy in relation to filler surface modification is shown.

  11. Environmentally benign electroless nickel plating using supercritical carbon-dioxide on hydrophilically modified acrylonitrile-butadiene-styrene

    Science.gov (United States)

    Tengsuwan, Siwach; Ohshima, Masahiro

    2014-08-01

    Electroless Ni-P plating using supercritical carbon dioxide (scCO2) in conjunction with copolymer-based hydrophilic modification was applied to an acrylonitrile-butadiene-styrene (ABS) substrate. The surface of ABS substrate was hydrophilically modified by blending with a multi-block copolymer, poly(ether-ester-amide)s (PEEA), in injection molding process. The substrate was then impregnated with Pd(II)-hexafluoroacetylacetonate, Pd(hfa)2, using scCO2, followed by the electroless plating reaction. ABS/PEEA substrates with different PEEA to ABS blend ratios and different volume ratios of butadiene to the styrene-acrylonitrile copolymer (SAN) matrix were prepared to investigate how the dispersed PEEA and butadiene domains affected the blend morphology and the adhesive strength of the plating metal-to-polymer contact. Increasing the PEEA copolymer to ABS blend ratio increased the mass transfer rate of the plating solution in the ABS substrate. Consequently, the metal-polymer composite layer became thicker, which increased the adhesive strength of the metal-to-polymer contact because of the anchoring effect. The butadiene domains appeared to attract the Pd catalyst precursor, and thus, the proportion of butadiene in the ABS matrix also affected the adhesive strength of the contact between the metal layer and the substrate. The ABS substrate was successfully plated with a Ni-P metal layer with an average adhesive strength of 9.1 ± 0.5 N cm-1 by choosing appropriate ABS/PEEA blend ratios and a Pd(hfa)2 concentration.

  12. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  13. Characterization of hydrophilic-rich phase mimic in dentin adhesive and computer-aided molecular design of water compatible visible light initiators

    Science.gov (United States)

    Abedin, Farhana

    photosensitizers specifically for the hydrophilic-rich phase of dental adhesives. It was observed that the degree of conversion of the hydrophilic-rich mimics is dominated by the photo-initiator concentration and not the cross-linker. A secondary rate maxima was observed in the case of hydrophilic-rich phase mimics which was associated with the formation of microgels during polymerization. A polymerization mechanism involving polymerization- and solvent-induced phase separation was proposed for the hydrophilic-rich mimics. The hydrophilic dental resins were sensitive to light intensity, i.e. at low light intensities the degree of conversion of the hydrophilic resin was reduced substantially in the presence of camphorquinone/ethyl 4-(dimethylamino)benzoate as photo-initiators, whereas a substantial degree of conversion was observed for the hydrophobic resin even at these lower light intensities. The addition of iodonium salt in the hydrophilic resin significantly improved the degree of conversion of the hydrophilic resin at low light intensities. These studies also showed that the iodonium salt could lead to enhanced cyclization and shorter polymer chain lengths within the hydrophilic-rich phase. For the physically separated hydrophilic-rich phase specimens, it was observed that in the presence of the conventional photo-initiator system (camphorquinone/ethyl 4-(dimethylamino)benzoate), there was no polymerization, mostly due to the insufficient partition concentrations of the photo-initiator components within this phase. The addition of iodoinum salt in this case significantly improved the degree of conversion but it was still significantly lower. These studies indicated that the overall polymerization efficiency of the hydrophilic-rich phase was lower than the hydrophobic-rich phase. The lower polymerization efficiency of the hydrophilic-rich phase led to a phase that lacks integrity; the hydrophilic-rich phase could be infiltrated by oral fluids and cariogenic bacteria. The

  14. Accumulation of solvent-soluble and solvent-insoluble antioxidant phenolics in edible bean sprouts: implication of germination

    OpenAIRE

    Ren-You Gan; Wing-Yee Lui; Ming-Fu Wang; Zhong-Quan Sui

    2016-01-01

    Background: Edible bean sprouts are popular fresh vegetables widely recognized for their nutritional quality. However, while their antioxidant capacity and phenolic composition in both solvent-soluble and solvent-insoluble extracts has not been systematically evaluated. Methods: The antioxidant capacity and phenolic composition in both solvent-soluble and solvent-insoluble fractions of 12 cultivars of edible bean sprouts were evaluated, and relationships of antioxidant cap...

  15. Amyloid precursor protein, although partially detergent-insoluble in mouse cerebral cortex, behaves as an atypical lipid raft protein.

    OpenAIRE

    Parkin, E T; Turner, A J; Hooper, N M

    1999-01-01

    Lipid rafts are regions of the plasma membrane that are enriched in cholesterol, glycosphingolipids and acylated proteins, and which have been proposed as sites for the proteolytic processing of the Alzheimer's amyloid precursor protein (APP). Lipid rafts can be isolated on the basis of their insolubility in Triton X-100 at 4 degrees C, with the resulting low-density, detergent-insoluble glycolipid-enriched fraction (DIG) being isolated by flotation through a sucrose density gradient. The det...

  16. Photovoltaic Performance of Polymers Based on Dithienylthienopyrazines Bearing Thermocleavable Benzoate Esters

    DEFF Research Database (Denmark)

    Petersen, Martin Helgesen; Krebs, Frederik C

    2010-01-01

    are in the range of 1.17−1.37 eV. The polymers were explored as donor materials in bulk heterojunction solar cells together with PCBM as the acceptor material where they were shown to exhibit a photoresponse in the full absorption range up to 900 nm and power conversion efficiencies of up to 1.21% under 1 sun......, and a second weight loss above 400 °C, corresponding to loss of CO2 and decomposition. Upon thermocleavage the power conversion efficiency decreased for all the polymers while the polymer films became insoluble which was desired in the context of multilayer film processing. Thermocleavable low......-band-gap materials can potentially offer better light harvesting, better operational stability, and a higher level of permissible processing conditions due to the insolubility of thermocleaved films in all solvents....

  17. Frictional forces between hydrophilic and hydrophobic particle coated nanostructured surfaces

    DEFF Research Database (Denmark)

    Hansson, Petra M; Claesson, Per M.; Swerin, Agne

    2013-01-01

    not in itself provide any information on why the friction coefficient is different for different material combinations. In this study, friction forces between a colloidal probe and nanostructured particle coated surfaces in an aqueous environment exhibiting different roughness length scales were measured...... by utilizing the atomic force microscope (AFM). The chemistry of the surfaces and the probe was varied between hydrophilic silica and hydrophobized silica. For hydrophilic silica surfaces, the friction coefficient was significantly higher for the particle coated surfaces than on the flat reference surface. All...... the particle coated surfaces exhibited similar friction coefficients, from which it may be concluded that the surface geometry, and not the roughness amplitude per se, influenced the measured friction. During measurements with hydrophobic surfaces, strong adhesive forces related to the formation of a bridging...

  18. Stability and selectivity of alkaline proteases in hydrophilic solvents

    DEFF Research Database (Denmark)

    Pedersen, Lars Haastrup; Ritthitham, Sinthuwat; Pleissner, Daniel

    2008-01-01

    Hydrophilic, organic solvents can be used as co-solvents with water to produce one phase systems sustaining optimal mass transfer of substrates and products of mixed polarity in biocatalysed processes. At concentrations below 50 % hydrophilic solvents can even have a stabilising effect on alkaline...... active molecules and carriers, and in synthesis of carbohydrate derivatives with designed functional properties.  When it comes to regio-selectivity of alkaline proateses on carbohydrates both the properties of the particular enzyme and the influence of the solvent is determining for the position...... [10]. This way acylation of a secondary hydroxyl group situated on the glucose moiety of sucrose was obtained. The initial reaction rate of acylation was not effected by the fatty acid chain length of the acyl donor. The half life of the enzyme in de-ioniset water was 4 minutes whereas in 100% DMF...

  19. Pretreatment and Membrane Hydrophilic Modification to Reduce Membrane Fouling

    Directory of Open Access Journals (Sweden)

    Huaqiang Chu

    2013-09-01

    Full Text Available The application of low pressure membranes (microfiltration/ultrafiltration has undergone accelerated development for drinking water production. However, the major obstacle encountered in its popularization is membrane fouling caused by natural organic matter (NOM. This paper firstly summarizes the two factors causing the organic membrane fouling, including molecular weight (MW and hydrophilicity/hydrophobicity of NOM, and then presents a brief introduction of the methods which can prevent membrane fouling such as pretreatment of the feed water (e.g., coagulation, adsorption, and pre-oxidation and membrane hydrophilic modification (e.g., plasma modification, irradiation grafting modification, surface coating modification, blend modification, etc.. Perspectives of further research are also discussed.

  20. Fluctuations of water near extended hydrophobic and hydrophilic surfaces.

    Science.gov (United States)

    Patel, Amish J; Varilly, Patrick; Chandler, David

    2010-02-04

    We use molecular dynamics simulations of the SPC-E model of liquid water to derive probability distributions for water density fluctuations in probe volumes of different shapes and sizes, both in the bulk as well as near hydrophobic and hydrophilic surfaces. Our results are obtained with a biased sampling of coarse-grained densities that is easily combined with molecular dynamics integration algorithms. Our principal result is that the probability for density fluctuations of water near a hydrophobic surface, with or without surface water attractions, is akin to density fluctuations at the water-vapor interface. Specifically, the probability of density depletion near the surface is significantly larger than that in the bulk, and this enhanced probability is responsible for hydrophobic forces of assembly. In contrast, we find that the statistics of water density fluctuations near a model hydrophilic surface are similar to that in the bulk.

  1. Polymer flooding

    Energy Technology Data Exchange (ETDEWEB)

    Littmann, W.

    1988-01-01

    This book covers all aspects of polymer flooding, an enhanced oil recovery method using water soluble polymers to increase the viscosity of flood water, for the displacement of crude oil from porous reservoir rocks. Although this method is becoming increasingly important, there is very little literature available for the engineer wishing to embark on such a project. In the past, polymer flooding was mainly the subject of research. The results of this research are spread over a vast number of single publications, making it difficult for someone who has not kept up-to-date with developments during the last 10-15 years to judge the suitability of polymer flooding to a particular field case. This book tries to fill that gap. An indispensable book for reservoir engineers, production engineers and lab. technicians within the petroleum industry.

  2. Organometallic Polymers.

    Science.gov (United States)

    Carraher, Charles E., Jr.

    1981-01-01

    Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

  3. New hydrophilic HPMA-based polymers for bioreversible shielding of gene delivery vectors

    Czech Academy of Sciences Publication Activity Database

    Laga, Richard; Koňák, Čestmír; Šubr, Vladimír; Ulbrich, Karel

    2009-01-01

    Roč. 210, 13-14 (2009), s. 1138-1148 ISSN 1022-1352 R&D Projects: GA AV ČR KAN200200651; GA ČR GA202/09/2078 Institutional research plan: CEZ:AV0Z40500505 Keywords : N-(2-hydroxypropyl)methacrylamide copolymers * polyelectrolyte complexes * latex nanoparticles Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.570, year: 2009

  4. Coating of nanoparticles bearing amino groups on the surface with hydrophilic HPMA-based polymers

    Czech Academy of Sciences Publication Activity Database

    Laga, Richard; Koňák, Čestmír; Šubr, Vladimír; Ulbrich, Karel

    2007-01-01

    Roč. 285, č. 13 (2007), s. 1509-1514 ISSN 0303-402X Grant - others:FP6-2002-LifeSciHealth European Commission Funded Research,(EU) GIANT 512087 Institutional research plan: CEZ:AV0Z40500505 Source of funding: R - rámcový projekt EK Keywords : polyelectrolyte complex * latex * nanoparticle Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.620, year: 2007

  5. Osmotic-driven mass transport of water: impact on the adhesiveness of hydrophilic polymers.

    Science.gov (United States)

    Borde, Annika; Bergstrand, Anna; Gunnarsson, Cecilia; Larsson, Anette

    2010-01-15

    Adhesion is an important property for the functionality of many medical devices. One reason for the development of adhesive forces is dehydration caused by mass transport of water. Osmotic pressure is one main driving force for mass transport and the correlation between osmotic pressure and adhesive force has not been studied yet, which was the aim of the present study. A model system was used where a Carbopol tablet was lowered onto a 1% (w/w) agarose gel. The force required to detach the tablet (adhesive force) and the weight gain of the tablet (as a measure of transported water) were determined. Sodium chloride and mannitol were added to the agarose gel to decrease the osmotic pressure difference between the agarose gel and the partially hydrated Carbopol tablet. This resulted in a decrease of both mass transport and adhesive force. In addition, experiments with restricted water transport within the agarose gel were performed by preparing gels with different agarose concentrations. An increase of the agarose concentration resulted in decreased water transport and higher adhesive forces. Hence, the results confirmed our hypothesis that osmotic-driven mass transport and restricted mass transport of water correlate very well with the adhesive force.

  6. Low-Temperature Polymer Bonding Using Surface Hydrophilic Treatment for Chemical/Bio Microchips

    OpenAIRE

    Shinohara, Hidetoshi; Mizuno, Jun; Shoji, Shuichi

    2010-01-01

    This research was supported by the Grant-in-Aid for Specially Promoted Research "Establishment of Electrochemical Device Engineering", and the Waseda University Global COE Program "International Research and Education Center for Ambient SoC" sponsored by MEXT, Japan.

  7. Preparation and characterization of dopamine-decorated hydrophilic carbon black

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Lijun; Lu Yonglai [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing 100029 (China); Wang Yiqing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029 (China); Zhang Liqun [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing 100029 (China); Wang Wencai, E-mail: wangw@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029 (China)

    2012-05-01

    Inspired by the bio-adhesive proteins secreted by mussels for attachment to almost all wet substrates, a facile method involving oxidative polymerization of dopamine was proposed to prepare highly hydrophilic carbon black (CB) particles. A self-assembled polydopamine (PDA) ad-layer was formed via the oxidative polymerization of dopamine on the surface of CB simply by dipping the CB into an alkaline dopamine solution and mildly stirring at room temperature. The process is simple, controllable, and environment-friendly. The surface composition and structure of the CB were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The surface morphology of the CB was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the PDA ad-layer was successfully deposited on the CB surfaces. The PDA-functionalized CB (CB-PDA) gave a stable colloidal dispersion in water. Contact angle measurement results indicated that the hydrophilicity of CB was significantly improved after dopamine modification. TGA results confirmed that the modified CB maintained good heat resistance. The method provided a facile route to prepare hydrophilic CB having terminal hydroxyl groups.

  8. Anionic and cationic Hofmeister effects on hydrophobic and hydrophilic surfaces.

    Science.gov (United States)

    Schwierz, Nadine; Horinek, Dominik; Netz, Roland R

    2013-02-26

    Using a two-step modeling approach, we address the full spectrum of direct, reversed, and altered ionic sequences as the charge of the ion, the charge of the surface, and the surface polarity are varied. From solvent-explicit molecular dynamics simulations, we extract single-ion surface interaction potentials for halide and alkali ions at hydrophilic and hydrophobic surfaces. These are used within Poisson-Boltzmann theory to calculate ion density and electrostatic potential distributions at mixed polar/unpolar surfaces for varying surface charge. The resulting interfacial tension increments agree quantitatively with experimental data and capture the Hofmeister series, especially the anomaly of lithium, which is difficult to obtain using continuum theory. Phase diagrams that feature different Hofmeister series as a function of surface charge, salt concentration, and surface polarity are constructed from the long-range force between two surfaces interacting across electrolyte solutions. Large anions such as iodide have a high hydrophobic surface affinity and increase the effective charge magnitude on negatively charged unpolar surfaces. Large cations such as cesium also have a large hydrophobic surface affinity and thereby compensate an external negative charge surface charge most efficiently, which explains the well-known asymmetry between cations and anions. On the hydrophilic surface, the size-dependence of the ion surface affinity is reversed, explaining the Hofmeister series reversal when comparing hydrophobic with hydrophilic surfaces.

  9. Distributed Pore Chemistry in Porous Organic Polymers in Tissue Culture Flasks

    Science.gov (United States)

    Koontz, Steven L. (Inventor)

    1999-01-01

    A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclose. The substrate may be subsequently optionally grated with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphorylcholine groups, platelet adhesion preventing polymers, albumin adhesion promoters, and the like. The compatibilized substrate may also have a living cell layer adhered thereto. The atomic oxygen is preferably produced by a flowing afterglow microwave discharge, wherein the substrate resides in a sidearm out of the plasma. Also, methods for culturing cells for various purposes using the various membranes are disclosed as well. Also disclosed are porous organic polymers having a distributed pore chemistry (DPC) comprising hydrophilic and hydrophobic regions, and a method for making the DPC by exposing the polymer to atomic oxygen wherein the rate of hydrophilization is greater than the rate of mass loss.

  10. Environmental monitoring study of linear alkylbenzene sulfonates and insoluble soap in Spanish sewage sludge samples.

    Science.gov (United States)

    Cantarero, Samuel; Zafra-Gómez, Alberto; Ballesteros, Oscar; Navalón, Alberto; Reis, Marco S; Saraiva, Pedro M; Vílchez, José L

    2011-01-01

    In this work we present a monitoring study of linear alkylbenzene sulfonates (LAS) and insoluble soap performed on Spanish sewage sludge samples. This work focuses on finding statistical relations between LAS concentrations and insoluble soap in sewage sludge samples and variables related to wastewater treatment plants such as water hardness, population and treatment type. It is worth to mention that 38 samples, collected from different Spanish regions, were studied. The statistical tool we used was Principal Component Analysis (PC), in order to reduce the number of response variables. The analysis of variance (ANOVA) test and a non-parametric test such as the Kruskal-Wallis test were also studied through the estimation of the p-value (probability of obtaining a test statistic at least as extreme as the one that was actually observed, assuming that the null hypothesis is true) in order to study possible relations between the concentration of both analytes and the rest of variables. We also compared LAS and insoluble soap behaviors. In addition, the results obtained for LAS (mean value) were compared with the limit value proposed by the future Directive entitled "Working Document on Sludge". According to the results, the mean obtained for soap and LAS was 26.49 g kg(-1) and 6.15 g kg(-1) respectively. It is worth noting that LAS mean was significantly higher than the limit value (2.6 g kg(-1)). In addition, LAS and soap concentrations depend largely on water hardness. However, only LAS concentration depends on treatment type.

  11. Dietary total and insoluble fiber intakes are inversely associated with prostate cancer risk.

    Science.gov (United States)

    Deschasaux, Mélanie; Pouchieu, Camille; His, Mathilde; Hercberg, Serge; Latino-Martel, Paule; Touvier, Mathilde

    2014-04-01

    Although experimental data suggest a potentially protective involvement of dietary fiber in prostate carcinogenesis, very few prospective studies have investigated the relation between dietary fiber intake and prostate cancer risk, and those have had inconsistent results. Our objective was to study the association between dietary fiber intake (overall, insoluble, soluble, and from different sources, such as cereals, vegetables, fruits, and legumes) and prostate cancer risk. Stratifications by excess weight status, insulin-like growth factors, and amount of alcohol intake were also considered. This prospective analysis included 3313 men from the Supplémentation en Vitamines et Minéraux Antioxydants (SU.VI.MAX) cohort who completed at least 3 24-h dietary records. One hundred thirty-nine incident prostate cancers were diagnosed between 1994 and 2007 (median follow-up of 12.6 y). Associations between quartiles of energy-adjusted dietary fiber intake and prostate cancer risk were characterized by multivariate Cox proportional hazards models. Prostate cancer risk was inversely associated with total dietary fiber intake (HR of quartile 4 vs. quartile 1 = 0.47; 95% CI: 0.27, 0.81; P = 0.001), insoluble (HR = 0.46; 95% CI: 0.27, 0.78; P = 0.001), and legume (HR = 0.55; 95% CI: 0.32, 0.95; P = 0.04) fiber intakes. In contrast, we found no association between prostate cancer risk and soluble (P = 0.1), cereal (P = 0.7), vegetable (P = 0.9), and fruit (P = 0.4) fiber intakes. In conclusion, dietary fiber intake (total, insoluble, and from legumes but not soluble or from cereals, vegetables, and fruits) was inversely associated with prostate cancer risk, consistent with mechanistic data.

  12. In Situ Crystallization of the Insoluble Anhydrite AII Phase in Graphene Pockets.

    Science.gov (United States)

    Lehnert, Tibor; Kinyanjui, Michael K; Ladenburger, Anita; Rommel, Dimitri; Wörle, Katharina; Börrnert, Felix; Leopold, Kerstin; Kaiser, Ute

    2017-08-22

    Single-distilled water encapsulated in graphene pockets has been studied by aberration-corrected high-resolution transmission electron microscopy and electron energy loss spectroscopy at an acceleration voltage of 80 kV. Inside the graphene pockets, crystallization and in situ crystal growth are reported and identified as the insoluble AII phase of CaSO4 (anhydrite) in a quasi-two-dimensional system. Its formation condition is discussed with respect to the possible temperature and van der Waals pressure between the graphene sheets.

  13. Morphological control of inter-penetrating polymer networks

    Science.gov (United States)

    Hansen, Marion

    1989-01-01

    Synthetic organic polymer chemistry has been successful in producing composition of matter with thermal oxidation stability and progressively higher glass transition temperatures. In part, this was done by increasing the steric-hindrance of moieties in the chain of a macromolecule. The resulting polymers are usually quite insoluble and produce molten polymers of very high viscosities. These types of polymers are not easily processed into graphite fiber prepregs by melt or solution impregnation methods. Hence, a technological need exists to produce new knowledge of how to produce polymer-fiber composites from this class of polymers. The concept of freeze drying amic-acid prepolymers with reactive thermoplastic was proposed as a research topic for the ASEE/NASA Summer Faculty Program of 1989 as a means of producing polymer-fiber composites. This process scheme has the thermodynamic attribute that the magnitude of phase separation due to differences in solubility of two organic constituents in solution will be greatly reduced by removing a solvent not by evaporation but by sublimation. Progress to date on evaluating this polymer processing concept is briefly outlined.

  14. The glycogen of Galdieria sulphuraria as alternative to starch for the production of slowly digestible and resistant glucose polymers

    NARCIS (Netherlands)

    Martinez-Garcia, Marta; Kormpa, Akrivi; van der Maarel, Marc J. E. C.

    2017-01-01

    Highly branched glucose polymers produced from starch are applied in various products, such as peritoneal dialysis solutions and sports drinks. Due to its insoluble, granular nature, the use of native starch as substrate requires an energy consuming pre-treatment to achieve solubilization at the

  15. Micellar Structures of Hydrophilic/Lipophilic and Hydrophilic/Fluorophilic Poly(2-oxazoline) Diblock Copolymers in Water

    DEFF Research Database (Denmark)

    Ivanova, Ruzha; Komenda, Thomas; Bonné, Tune B.

    2008-01-01

    Amphiphilic poly(2-alkyl-2-oxazoline) diblock copolymers of 2-methyl-2-oxazoline (MOx) building the hydrophilic block and either 2-nonyl-2-oxazoline (NOx) for the hydrophobic or 2-(1H,1H',2H,2H'-perfluorohexyl)-2-oxazoline (FOx) for the fluorophilic block were synthesized by sequential living cat......, as observed by SANS and TEM. In water, the micelles with fluorophilic and lipophilic cores do not mix, but coexist....

  16. Use of Atomic Oxygen for Increased Water Contact Angles of Various Polymers for Biomedical Applications

    Science.gov (United States)

    deGroh, Kim; Berger, Lauren; Roberts, Lily

    2009-01-01

    The purpose of this study was to determine the effect of atomic oxygen (AO) exposure on the hydrophilicity of nine different polymers for biomedical applications. Atomic oxygen treatment can alter the chemistry and morphology of polymer surfaces, which may increase the adhesion and spreading of cells on Petri dishes and enhance implant growth. Therefore, nine different polymers were exposed to atomic oxygen and water-contact angle, or hydrophilicity, was measured after exposure. To determine whether hydrophilicity remains static after initial atomic oxygen exposure, or changes with higher fluence exposures, the contact angles between the polymer and water droplet placed on the polymer s surface were measured versus AO fluence. The polymers were exposed to atomic oxygen in a 100-W, 13.56-MHz radio frequency (RF) plasma asher, and the treatment was found to significantly alter the hydrophilicity of non-fluorinated polymers. Pristine samples were compared with samples that had been exposed to AO at various fluence levels. Minimum and maximum fluences for the ashing trials were set based on the effective AO erosion of a Kapton witness coupon in the asher. The time intervals for ashing were determined by finding the logarithmic values of the minimum and maximum fluences. The difference of these two values was divided by the desired number of intervals (ideally 10). The initial desired fluence was then multiplied by this result (2.37), as was each subsequent desired fluence. The flux in the asher was determined to be approximately 3.0 x 10(exp 15) atoms/sq cm/sec, and each polymer was exposed to a maximum fluence of 5.16 x 10(exp 20) atoms/sq cm.

  17. Effect of Different Polymer Concentration on Drug Release Rate and Physicochemical Properties of Mucoadhesive Gastroretentive Tablets

    OpenAIRE

    Agarwal, Shweta; Murthy, R. S. R.

    2015-01-01

    Mucoadhesive tablets have emerged as potential candidates for gastroretentive drug delivery providing controlled release along with prolonged gastric residence time. Gastroretentive mucoadhesive tablets could result in increased bioavailability due to prolonged gastric residence time. A hydrophilic matrix system was developed as mucoadhesion is achievable on appropriate wetting and swelling of the polymers used. The polymers were so chosen so as to provide a balance between swelling, mucoadhe...

  18. Partial hydrophilic modification of biaxially oriented polypropylene film by an atmospheric pressure plasma jet with the allylamine monomer

    Science.gov (United States)

    Chen, W. X.; Yu, J. S.; Hu, W.; Chen, G. L.

    2016-11-01

    In this paper, the partial modification of the biaxially oriented polypropylene (BOPP) film for potential biological and packaging applications was achieved via hydrophilic modification using atmospheric pressure plasma jet (APPJ). In the APPJ system, the allylamine (ALA) monomer was polymerized on the BOPP surface by either the Ar/O2 or the He/O2 plasma. The results showed that plasmatic modification created many micro/nano sized holes on the BOPP film, which increased the surface roughness dramatically and the increased roughness enhanced the combining intensity between the BOPP film and the ALA polymer. However, such a plasmatic modification increased the water vapor permeability. The FTIR and XPS characterizations showed that the amine groups were grafted onto the BOPP film, and the contact angle of the BOPP film decreases from 98.5° to 8°. Compared with the BOPP films treated by the Ar or He plasma, the barrier property of the modified BOPP film increased significantly when the ALA polymer was incorporated. The bio-affinity/toxicity of ALA polymer was illustrated by the attachment of the cultured SMMC-7721 hepatoma cells on the modified BOPP film. The significant enhancement in the cell density indicated that modified BOPP film was highly bio-compatible and non-toxic, especially treated with the Ar/O2/ALA plasma.

  19. Comparative characteristics of the insoluble part of organic matter of sediments

    Energy Technology Data Exchange (ETDEWEB)

    Kuprin, P.N.; Sorokin, V.M.

    1980-01-01

    Comparative characteristics are presented for the composition of the insoluble part of organic matter (IOM) of sediments of offshore basins from different climate zones. The IOM of the Holocene sediments of the White Sea is characterized by a significant admixture which has a terrestrial (plant) origin. The IOM of the Holocene sediments of the Sidra gulf of the Mediterranean Sea, having a clearly planktonogenic origin is distinguished by significant acidity. The IOM of the middle Wurm deposits record admixture of compounds inherent to terrestrial vegetation. A similar composition of IOM can be associated partially with increase in the role of the terrigenous organic chemistry during the interglacial thawing, and partially with oxidation of the original organic matter. The insoluble part of concentrated and scattered differences in the organic matter of deep-sea Holocene sediments and late Miocene deposits of the Black Sea is characterized by sapropel composition and was formed through phytoplanktons. In this case greater degree of transformation of the IOM from the C /SUB org/ -enriched late Miocene deposits is found as compared to the IOM of the sapropel-like Holocene sediments.

  20. Total, Soluble and Insoluble Oxalate Contents of Ripe Green and Golden Kiwifruit

    Directory of Open Access Journals (Sweden)

    Hà Vũ Hồng Nguyễn

    2013-03-01

    Full Text Available Three bulk samples of two different cultivars of kiwifruit, green (Actinidia deliciosa L. and golden (Actinidia chinensis L. were bought ripe, ready to eat from a local market. The aim of the study was to determine the oxalate composition of each of the three fractions of kiwifruit, namely skin, pulp and seeds. The pulp consisted of 90.4% of the edible portion of the two cultivars while the skin and seeds made up a mean of 8.0% and 1.6% respectively. Total oxalate was extracted with 2.0 M HCL at 21 °C for 15 min and soluble oxalates extracted at 21 °C in water for 15 min from each fraction. The total and soluble oxalate compositions of each fraction were determined using ion exchange HPLC chromatography. The pulp of golden kiwifruit contained lower amounts of total oxalates (15.7 vs. 19.3 mg/100 g FW and higher amounts of soluble oxalates (8.5 vs. 7.6 mg/100 g FW when compared to the green cultivar. The skin of the green cultivar contained lower levels of insoluble oxalates (36.9 vs. 43.6 mg/100 g FW, while the seeds of the green cultivar contained higher levels of insoluble oxalates 106.7 vs. 84.7 mg/100 g FW.

  1. Nano and microparticle engineering of water insoluble drugs using a novel spray-drying process.

    Science.gov (United States)

    Schafroth, Nina; Arpagaus, Cordin; Jadhav, Umesh Y; Makne, Sushil; Douroumis, Dennis

    2012-02-01

    In the current study nano and microparticle engineering of water insoluble drugs was conducted using a novel piezoelectric spray-drying approach. Cyclosporin A (CyA) and dexamethasone (DEX) were encapsulated in biodegradable poly(D,L-lactide-co-glycolide) (PLGA) grades of different molecular weights. Spray-drying studies carried out with the Nano Spray Dryer B-90 employed with piezoelectric driven actuator. The processing parameters including inlet temperature, spray mesh diameter, sample flow rate, spray rate, applied pressure and sample concentration were examined in order to optimize the particle size and the obtained yield. The process parameters and the solute concentration showed a profound effect on the particle engineering and the obtained product yield. The produced powder presented consistent and reproducible spherical particles with narrow particle size distribution. Cyclosporin was found to be molecularly dispersed while dexamethasone was in crystalline state within the PLGA nanoparticles. Further evaluation revealed excellent drug loading, encapsulation efficiency and production yield. In vitro studies demonstrated sustained release patterns for the active substances. This novel spray-drying process proved to be efficient for nano and microparticle engineering of water insoluble active substances. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Characterisation of detergent-insoluble membranes in pollen tubes of Nicotiana tabacum (L.

    Directory of Open Access Journals (Sweden)

    Alessandra Moscatelli

    2015-02-01

    Full Text Available Pollen tubes are the vehicle for sperm cell delivery to the embryo sac during fertilisation of Angiosperms. They provide an intriguing model for unravelling mechanisms of growing to extremes. The asymmetric distribution of lipids and proteins in the pollen tube plasma membrane modulates ion fluxes and actin dynamics and is maintained by a delicate equilibrium between exocytosis and endocytosis. The structural constraints regulating polarised secretion and asymmetric protein distribution on the plasma membrane are mostly unknown. To address this problem, we investigated whether ordered membrane microdomains, namely membrane rafts, might contribute to sperm cell delivery. Detergent insoluble membranes, rich in sterols and sphingolipids, were isolated from tobacco pollen tubes. MALDI TOF/MS analysis revealed that actin, prohibitins and proteins involved in methylation reactions and in phosphoinositide pattern regulation are specifically present in pollen tube detergent insoluble membranes. Tubulins, voltage-dependent anion channels and proteins involved in membrane trafficking and signalling were also present. This paper reports the first evidence of membrane rafts in Angiosperm pollen tubes, opening new perspectives on the coordination of signal transduction, cytoskeleton dynamics and polarised secretion.

  3. [Soluble and insoluble dietary fiber in cereals and legumes cultivated in Chile].

    Science.gov (United States)

    Pak, N; Ayala, C; Vera, G; Pennacchiotti, I; Araya, H

    1990-03-01

    Insoluble, soluble and total dietary fiber (DF) were determined in 35 varieties of certified whole seeds (without processing) of cereals (rice, oat, rye, and wheat) and legumes (pea, cowpea, beans, chikpea, lentil and lupine). The enzymatic method of Asp, Johansson and Siljestrom was used, with modifications in relation to time of incubation with alpha amylase, filtration system and volumes of the filtrates. Results were expressed as g/100 g dry weight. Total DF for cereals showed a range from 10.1 (wheat var. Chasqui) to 22.2 (rice var Quella). Rye, var. Tetra Baer and oats var. Pony Baer presented the highest soluble fiber content (3.3 and 3.9, respectively). In legumes, total DF fluctuated between 12.7 (pea, var. yellow) and 36.6 (lupine, var. Multolupa). Bean, var. Pinto INIA and lupine var. Multolupa presented the highest soluble fiber values (5.8 for both). Based on the results of this research work, it might be concluded that great variation exists in regard to the amount of total soluble and insoluble DF in cereals and legumes, a fact which impedes generalization as to its content in each food item.

  4. Biological applications of hydrophilic C60 derivatives (hC60s)- a structural perspective.

    Science.gov (United States)

    Zhu, Xiaolei; Sollogoub, Matthieu; Zhang, Yongmin

    2016-06-10

    Reactive oxygen species (ROS) generation and radical scavenging are dual properties of hydrophilic C60 derivatives (hC60s). hC60s eliminate radicals in dark, while they produce reactive oxygen species (ROS) in the presence of irradiation and oxygen. Compared to the pristine C60 suspension, the aqueous solution of hC60s is easier to handle in vivo. hC60s are diverse and could be placed into two general categories: covalently modified C60 derivatives and pristine C60 solubilized non-covalently by macromolecules. In order to present in detail, the above categories are broken down into 8 parts: C60(OH)n, C60 with carboxylic acid, C60 with quaternary ammonium salts, C60 with peptide, C60 containing sugar, C60 modified covalently or non-covalently solubilized by cyclodextrins (CDs), pristine C60 delivered by liposomes, functionalized C60-polymer and pristine C60 solubilized by polymer. Each hC60 shows the propensity to be ROS producer or radical scavenger. This preference is dependent on hC60s structures. For example, major application of C60(OH)n is radical scavenger, while pristine C60/γ-CD complex usually serves as ROS producer. In addition, the electron acceptability and innate hydrophobic surface confer hC60s with O2 uptake inhibition, HIV inhibition and membrane permeability. In this review, we summarize the preparation methods and biological applications of hC60s according to the structures. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Enhanced stability of low fouling zwitterionic polymer brushes in seawater with diblock architecture

    NARCIS (Netherlands)

    Quintana, R.; Gosa, M.; Janczewski, D.; Kutnyanszky, E.; Vancso, Gyula J.

    2013-01-01

    The successful implementation of zwitterionic polymeric brushes as antifouling materials for marine applications is conditioned by the stability of the polymer chain and the brush-anchoring segment in seawater. Here we demonstrate that robust, antifouling, hydrophilic polysulfobetaine-based brushes

  6. Electrically actuatable doped polymer flakes and electrically addressable optical devices using suspensions of doped polymer flakes in a fluid host

    Science.gov (United States)

    Trajkovska-Petkoska, Anka; Jacobs, Stephen D.; Marshall, Kenneth L.; Kosc, Tanya Z.

    2010-05-11

    Doped electrically actuatable (electrically addressable or switchable) polymer flakes have enhanced and controllable electric field induced motion by virtue of doping a polymer material that functions as the base flake matrix with either a distribution of insoluble dopant particles or a dopant material that is completely soluble in the base flake matrix. The base flake matrix may be a polymer liquid crystal material, and the dopants generally have higher dielectric permittivity and/or conductivity than the electrically actuatable polymer base flake matrix. The dopant distribution within the base flake matrix may be either homogeneous or non-homogeneous. In the latter case, the non-homogeneous distribution of dopant provides a dielectric permittivity and/or conductivity gradient within the body of the flakes. The dopant can also be a carbon-containing material (either soluble or insoluble in the base flake matrix) that absorbs light so as to reduce the unpolarized scattered light component reflected from the flakes, thereby enhancing the effective intensity of circularly polarized light reflected from the flakes when the flakes are oriented into a light reflecting state. Electro-optic devices contain these doped flakes suspended in a host fluid can be addressed with an applied electric field, thus controlling the orientation of the flakes between a bright reflecting state and a non-reflecting dark state.

  7. Antimocrobial Polymer

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, William F. (Utica, OH); Huang, Zhi-Heng (Walnut Creek, CA); Wright, Stacy C. (Columbus, GA)

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  8. Biocompatible, Biodegradable, and Electroactive Polyurethane-Urea Elastomers with Tunable Hydrophilicity for Skeletal Muscle Tissue Engineering.

    Science.gov (United States)

    Chen, Jing; Dong, Ruonan; Ge, Juan; Guo, Baolin; Ma, Peter X

    2015-12-30

    It remains a challenge to develop electroactive and elastic biomaterials to mimic the elasticity of soft tissue and to regulate the cell behavior during tissue regeneration. We designed and synthesized a series of novel electroactive and biodegradable polyurethane-urea (PUU) copolymers with elastomeric property by combining the properties of polyurethanes and conducting polymers. The electroactive PUU copolymers were synthesized from amine capped aniline trimer (ACAT), dimethylol propionic acid (DMPA), polylactide, and hexamethylene diisocyanate. The electroactivity of the PUU copolymers were studied by UV-vis spectroscopy and cyclic voltammetry. Elasticity and Young's modulus were tailored by the polylactide segment length and ACAT content. Hydrophilicity of the copolymer films was tuned by changing DMPA content and doping of the copolymer. Cytotoxicity of the PUU copolymers was evaluated by mouse C2C12 myoblast cells. The myogenic differentiation of C2C12 myoblasts on copolymer films was also studied by analyzing the morphology of myotubes and relative gene expression during myogenic differentiation. The chemical structure, thermal properties, surface morphology, and processability of the PUU copolymers were characterized by NMR, FT-IR, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and solubility testing, respectively. Those biodegradable electroactive elastic PUU copolymers are promising materials for repair of soft tissues such as skeletal muscle, cardiac muscle, and nerve.

  9. Development of medicated foams that combine incompatible hydrophilic and lipophilic drugs for psoriasis treatment.

    Science.gov (United States)

    Mirtič, Janja; Papathanasiou, Foteini; Temova Rakuša, Žane; GosencaMatjaž, Mirjam; Roškar, Robert; Kristl, Julijana

    2017-05-30

    The focus was on the development of medicated foam for incorporation of two incompatible active agents for psoriasis treatment; i.e., lipophilic cholecalciferol, and hydrophilic salicylic acid. Emphasis was given to formulation of a propellant-free foam, with sufficient foaming properties, physical and chemical stability, and low irritancy potential to maintain relevance for later translation into clinical practice. Various excipients and concentrations were examined to achieve suitable foam stability parameters, viscoelasticity, and bubble-size, which relate to foamability and spreadability. The major positive impact on these properties was through a combination of surfactants, and by inclusion of a viscosity-modifying polymer. Incorporation of the incompatible drugs was then examined, noting the instability of cholecalciferol in an acidic environment, with the design aim to separate the drug distributions among the different foam phases. Cholecalciferol was stabilized in the emulsion-based foam, with at least a 30-fold lower degradation rate constant compared to its aqueous solution. The composition of the emulsion-based foam itself protected cholecalciferol from degradation, as well as the addition of the radical-scavenging antioxidant tocopheryl acetate to the oil phase. With the patient in mind, the irritancy potential was also examined, which was below the set limit that defines a non-irritant dermal product. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Flexible and stretchable microbial fuel cells with modified conductive and hydrophilic textile.

    Science.gov (United States)

    Pang, Sumiao; Gao, Yang; Choi, Seokheun

    2018-02-15

    We built a flexible, stretchable microbial fuel cell (MFC) by laminating two functional components: a bioanode textile with a conductive and hydrophilic polymer coating and a solid-state cathode textile loaded with silver oxide. The textile MFC used Pseudomonas aeruginosa PAO1 as a biocatalyst to generate the maximum power and current density of 1.0µW/cm 2 and 6.3µA/cm 2 , respectively, which are comparable with or even higher than other flexible MFCs such as paper-based devices (~ a few µW/cm 2 ). Additionally, the textile MFC generated consistent power even with repeated 70 cycles of 50% stretching. A simple batch fabrication method simultaneously produced 20 individual 2cm × 2cm devices by using brushing, spraying, ironing, and computerized sewing, a process that will revolutionize the mass production of textile MFCs. This achievement is scientifically meaningful because developing textile MFCs requires integration of both electronic and fluidic components into the textile three-dimensionally. This flexible and stretchable energy harvesting device is expected to be easily integrated with the next generation stretchable electronics for realizing low-power, stand-alone, self-sustainable systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Synthesis and characterization of biodegradable aliphatic copolyesters with hydrophilic soft segments

    Directory of Open Access Journals (Sweden)

    JASNA DJONLAGIC

    2004-12-01

    Full Text Available In this study, the synthesis, structure and physical properties of two series of segmented poly(ester-ethers based on poly(butylene succinate and two different types of polyethers were investigated. The poly(ester-ethers were synthesized by transesterification reaction of dimethyl succinate, 1,4-butanediol and poly(ethylene oxide (PEO, Mn = 1000 g/mol in the first series, and poly(tetramethylene oxide (PTMO, Mn = 1000 g/mol in the second. The mass fraction of soft segments was varied between 10 and 50 mass. %. The effect of the introduction of two different polyether soft segments on the structure, thermal and rheological properties were investigated. The composition of the poly(ester-ethers, determined from their 1H-NMR spectra, showed that incorporation of soft polyether segments was successfully performed by the transesterification reaction in bulk. The molecular weight was estimated from solution viscosity measurements and complex dynamic viscosities. The thermal properties investigated by DSC indicated that the presence of soft segments lowers the melting and crystallization temperature of the hard phase, as well as the degree of crystallinity. Dynamical mechanical analysis was used to investigate the influence of composition on the rheological behavior of the segmented poly(ester-ethers. The results obtained from an enzymatic degradation test performed on some of the synthesized polymers showed that the biodegradability is enhanced with increasing hydrophilicity.

  12. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  13. Optofluidic Applications of Diblock Copolymer Derived Nanoporous Polymers

    DEFF Research Database (Denmark)

    Gopalakrishnan, Nimi

    and have refractive index around 1.33 i.e. close to water, the earth’s most abundant liquid. The objective of this Ph.D study is to design and develop a liquid core waveguide platform from nanoporous polymer materials rendering refractive indices below 1.33, and to investigate the optical waveguiding...... in these devices. Nanoporous materials with refractive index below 1.33 are obtained from self assembling polymers called block copolymers by selectively etching one of the polymer blocks from the self assembly. The effective index of the porous material is a weighted average of the refractive indices...... of the polymer and air in the self assembly. Using UV-assisted surface modification, the hydrophobic nanoporous materials are selectively made hydrophilic. On infiltration with water, the pores in the UV exposed region are filled, thereby increasing the effective index in these regions by a value of n=0...

  14. Applications of biopolymers and synthetic polymers blends: literature review

    Directory of Open Access Journals (Sweden)

    Lady Joana Rodríguez Sepúlveda

    2016-08-01

    Full Text Available Biopolymers are biodegradable commonly, fragile, hydrophilic and have low thermal resistance, which has limited its commercial application. In contrast, synthetic polymers or derived from non-renewable resources generally lower cost and limited or minimal biodegradability, have good mechanical and thermal characteristics. The blend of biopolymers and synthetic polymers provides materials with properties and reasonable costs for certain applications. This article is a literature review on the main applications recently reported for the most important blends of biopolymers and biodegradable synthetic polymers. The literature search was performed with the "Tree of Science" tool and narratively. The results showed that mixtures of aliphatic and polysaccharide polymers are the most used in engineering applications biological tissues, control drug delivery and packaging industry.

  15. Protein and bacterial interactions with nanostructured polymer coatings.

    Science.gov (United States)

    Juvonen, Helka; Oja, Terhi; Määttänen, Anni; Sarfraz, Jawad; Rosqvist, Emil; Riihimäki, Tiina A; Toivakka, Martti; Kulomaa, Markku; Vuorela, Pia; Fallarero, Adyary; Peltonen, Jouko; Ihalainen, Petri

    2015-12-01

    Adsorption of proteins and adhesion of bacteria to a surface is affected by chemical and physical interactions. In this study, polymer coatings and their ability to adsorb avidin and Staphylococcus aureus were investigated. The surface chemistry and topography of the polymer coatings was modified by changing the weight ratio of the hydrophobic polystyrene (PS) and the hydrophilic acrylonitrile butadiene styrene (ABS) components in the polymer blend. Avidin adsorbed less to the ABS phase compared with the PS phase. The side-on orientation of avidin on the ABS surface, however, resulted in a higher specific binding of biotinylated bovine serum albumin. Steric effects and hydrophobic protein-surface interactions decreased the activity of avidin on the PS phase. The increased hydrophobicity and roughness of the polymer coatings enhanced the adhesion of S. aureus. The avidin-coated latex surface with 55% relative surface coverage of the PS phase showed anti-microbial behavior. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Structure and dynamics of water inside hydrophobic and hydrophilic nanotubes

    Science.gov (United States)

    Köhler, Mateus Henrique; Bordin, José Rafael; da Silva, Leandro B.; Barbosa, Marcia C.

    2018-01-01

    We have used Molecular Dynamics simulations to investigate the structure and dynamics of TIP4P/2005 water confined inside nanotubes. The nanotubes have distinct sizes and were built with hydrophilic or hydrophobic sites, and we compare the water behavior inside each nanotube. Our results shows that the structure and dynamics are strongly influenced by polarity inside narrow nanotubes, where water layers were observed, and the influence is negligible for wider nanotubes, where the water has a bulk-like density profile. As well, we show that water at low density can have a smaller diffusion inside nanotubes than water at higher densities. This result is a consequence of water diffusion anomaly.

  17. Analysis of moniliformin in maize plants using hydrophilic interaction chromatography

    DEFF Research Database (Denmark)

    Sørensen, Jens Laurids; Nielsen, Kristian Fog; Thrane, Ulf

    2007-01-01

    A novel HPLC method was developed for detection of the Fusarium mycotoxin, moniliformin in whole maize plants. The method is based on hydrophilic interaction chromatography (HILIC) on a ZIC zwitterion column combined with diode array detection and negative electrospray mass spectrometry (ESI...... is comparable to current methods used. Limit of detection and quantification using ESI−-MS detection was 1 and 12 ng/g, respectively. Screening of maize samples infected with the moniliformin producing fungi F. avenaceum, F. tricinctum, or F. subglutinans detected moniliformin levels of 1–12 ng/g in 15 of 28...

  18. Corrigendum: Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

    Directory of Open Access Journals (Sweden)

    Espandar L

    2011-02-01

    Full Text Available Espandar L, Sikder S, Moshirfar M. Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision. Clin Ophthalmol. 2011;5:65–70.There was an error in the reported optic size of Lenstec’s Softec HD intraocular lens, which was reported to be 5.5 mm in Espandar et al’s work, but is 5.75 mm.Please see the specifications on Lenstec’s Web site for further details (see http://www.lenstec.com/lenstec/hd_specs.html.Read the original article

  19. Polymer physics

    CERN Document Server

    Gedde, Ulf W

    1999-01-01

    This book is the result of my teaching efforts during the last ten years at the Royal Institute of Technology. The purpose is to present the subject of polymer physics for undergraduate and graduate students, to focus the fundamental aspects of the subject and to show the link between experiments and theory. The intention is not to present a compilation of the currently available literature on the subject. Very few reference citations have thus been made. Each chapter has essentially the same structure: starling with an introduction, continuing with the actual subject, summarizing the chapter in 30D-500 words, and finally presenting problems and a list of relevant references for the reader. The solutions to the problems presented in Chapters 1-12 are given in Chapter 13. The theme of the book is essentially polymer science, with the exclusion of that part dealing directly with chemical reactions. The fundamentals in polymer science, including some basic polymer chemistry, are presented as an introduction in t...

  20. Conducting Polymers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Conducting Polymers - From a Laboratory Curiosity to the Market Place. S Ramakrishnan. Volume 16 Issue 12 December 2011 pp 1254-1265. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. Polymer Microneedles

    NARCIS (Netherlands)

    Yeshurun, Yehoshua; Hefetz, Meir; Berenschot, Johan W.; de Boer, Meint J.; Altpeter, Dominique; Boom, Garrit; Boom, G.

    2003-01-01

    A method for producing microneedles. The method including disposing a first layer of a radiation sensitive polymer on to a working surface and selectively irradiating the first layer such that the first layer has at least one irradiated region and at least one non-irradiated region. The method also

  2. Insoluble Fiber in Young Barley Leaf Suppresses the Increment of Postprandial Blood Glucose Level by Increasing the Digesta Viscosity

    Directory of Open Access Journals (Sweden)

    Akira Takano

    2013-01-01

    Full Text Available Barley (Hordeum vulgare L. is a well-known cereal plant. Young barley leaf is consumed as a popular green-colored drink, which is named “Aojiru” in Japan. We examined the effects of barley leaf powder (BLP and insoluble fibers derived from BLP on postprandial blood glucose in rats and healthy Japanese volunteers. BLP and insoluble fibers derived from BLP suppressed the increment of postprandial blood glucose levels in rats (, and increased the viscosity of their digesta. The insoluble fibers present in BLP might play a role in controlling blood glucose level by increasing digesta viscosity. In human, BLP suppressed the increment of postprandial blood glucose level only in those which exhibited higher blood glucose levels after meals (. BLP might suppress the increment of postprandial blood glucose level by increasing digesta viscosity in both of rats and humans who require blood glucose monitoring.

  3. Thiolated polymers: evaluation of their potential as dermoadhesive excipients.

    Science.gov (United States)

    Grießinger, Julia Anita; Bonengel, Sonja; Partenhauser, Alexandra; Ijaz, Muhammad; Bernkop-Schnürch, Andreas

    2017-02-01

    The objective of this study was to evaluate and compare four different thiolated polymers regarding their dermoadhesive potential. Therefore, three hydrophilic polymers (poly(acrylic acid), Carbopol 971 and carboxymethylcellulose) and a lipophilic polymer (silicone oil) were chosen to generate thiolated polymers followed by characterization. The total work of adhesion (TWA) and the maximum detachment force (MDF) of formulations containing modified and unmodified polymers were investigated on skin obtained from pig ears using a tensile sandwich technique. The synthesis of thiolated polymers provided 564 µmol, 1079 µmol, 482 µmol and 217 µmol thiol groups per gram poly(acrylic acid), Carbopol 971, carboxymethylcellulose and silicone oil, respectively. Hydrogels containing poly(acrylic acid)-cysteine, Carbopol 971-cysteine, and carboxymethylcellulose-cysteamine exhibited a 6-fold, 25-fold and 9-fold prolonged adhesion on porcine skin than the hydrogel formulations prepared from the corresponding unmodified polymers, respectively. Furthermore, thiolation of silicone oil with thioglycolic acid led to a 5-fold improvement in adhesion compared to the unmodified silicone oil. A comparison between the four thiolated polymer formulations showed a clear correlation between the amount of coupled thiol groups and the TWA. According to these results thiomers might also be useful excipients to provide a prolonged dermal resistance time of various formulations.

  4. Thermally stable water insoluble azo-azomethine dyes: synthesis, characterization and solvatochromic properties.

    Science.gov (United States)

    Khanmohammadi, Hamid; Rezaeian, Khatereh

    2012-11-01

    Six new water insoluble azo-azomethine dyes have been synthesized via condensation reaction of α,α'-bis(o-aminophenylthio)-1,2-xylene with substituted azo-coupled salicylaldehyde. The condensation reaction provides the expected bis-iminated azo-azomethine dyes in good yields, ranging from 59% to 90%. The dyes have been characterized by IR, UV-Vis and (1)H NMR spectroscopic methods as well as elemental analysis. The thermal behavior of the prepared dyes has been determined using thermogravimetry technique. Furthermore, the effect of various organic solvents with different polarities on the UV-Vis spectra of the dyes has been also studied. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Proteomic analysis of water insoluble proteins from normal and cataractous human lenses.

    Science.gov (United States)

    Harrington, V; Srivastava, O P; Kirk, M

    2007-09-14

    The purpose of the study was to compare and analyze the composition of crystallin species that exist in the water insoluble-urea soluble (WI-US) and water insoluble-urea insoluble (WI-UI) protein fractions of a human cataractous lens and an age-matched normal lens. The water soluble (WS) and water insoluble (WI) protein fractions from a 68-year-old normal lens and a 61-year-old cataractous lens were isolated, and the WI proteins were further solubilized in urea to separate WI-US and WI-UI protein fractions. The WI-US and WI-UI protein fractions from normal and cataractous lenses were individually analyzed by two-dimensional (2D) gel electrophoresis. The protein spots were excised from 2D gels, digested with trypsin, and analyzed by the matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) method. The tryptic peptides from individual spots were further analyzed by the electrospray tandem mass spectrometry (ES-MS/MS) method to determine their amino acid sequences. The comparative 2D gel electrophoretic analyses of WI-US proteins of normal and cataractous lenses showed that the majority of species in a normal lens (68 years old) and a cataractous lens (61 years old) had M(r) between 20 to 30 kDa. The ES-MS/MS analyses showed that the individual WI-US protein spots from normal and cataractous lenses contained mostly either alphaA- or alphaB-crystallin with beta-crystallins, or alpha- and beta-crystallins with filensin as well as vimentin. Similar sequence analyses of tryptic fragments of 2D gel spots of WI-UI proteins revealed that the normal lens showed either individual alphaA- and alphaB-crystallins, a mixture of betaA3/A1-, betaB1-, and betaB2-crystallins and filensin, betaA4-, betaB1-, betaB2-, betaS-crystallins and filensin, or alphaA-, alphaB1-, filensin, and vimentin or alphaB-, betaA3-, betaA4-, betaB1-, betaB2-, and betaS-crystallins. In contrast, the WI-UI proteins from a cataractous lens showed three intact crystallins (alphaB-, gamma

  6. Origin of initial burst in activity for Trichoderma reesei endo-glucanases hydrolyzing insoluble cellulose

    DEFF Research Database (Denmark)

    Murphy, Leigh; Cruys-Bagger, Nicolaj; Baumann, Martin J.

    2012-01-01

    The kinetics of cellulose hydrolysis have longbeen described by an initial fast hydrolysis rate, tapering rapidly off, leading to a process that takes days rather than hours to complete. This behavior has been mainly attributed to the action of cellobiohydrolases and often linked to the processive...... mechanism of this exo-acting group of enzymes. The initial kinetics of endo-glucanases (EGs) is far less investigated, partly due to a limited availability of quantitative assay technologies.Wehave used isothermal calorimetry to monitor the early time course of the hydrolysis of insoluble cellulose...... of the mechanisms underlying the initial kinetics, and it is suggested that the slowdown is linked to transient inactivation of enzyme on the cellulose surface. We propose, therefore, that the frequency of structures on the substrate surface that cause transient inactivation determine the extent of the burst phase....

  7. Polymer surface modification by plasmas and photons

    Science.gov (United States)

    Chan, C.-M.; Ko, T.-M.; Hiraoka, H.

    1996-05-01

    Polymers have been applied successfully in fields such as adhesion, biomaterials, protective coatings, friction and wear, composites, microelectronic devices, and thin-film technology. In general, special surface properties with regard to chemical composition, hydrophilicity, roughness, crystallinity, conductivity, lubricity, and cross-linking density are required for the success of these applications. Polymers very often do not possess the surface properties needed for these applications. However, they have excellent bulk physical and chemical properties, are inexpensive, and are easy to process. For these reasons, surface modification techniques which can transform these inexpensive materials into highly valuable finished products have become an important part of the plastics and many other industries. In recent years, many advances have been made in developing surface treatments to alter the chemical and physical properties of polymer surfaces without affecting bulk properties. Common surface modification techniques include treatments by flame, corona, plasmas, photons, electron beams, ion beams, X-rays, and γ-rays. Plasma treatment is probably the most versatile surface treatment technique. Different types of gases such as argon, oxygen, nitrogen, fluorine, carbon dioxide, and water can produce the unique surface properties required by various applications. For example, oxygen-plasma treatment can increase the surface energy of polymers, whereas fluorine-plasma treatment can decrease the surface energy and improve the chemical inertness. Cross-linking at a polymer surface can be introduced by an inert-gas plasma. Modification by plasma treatment is usually confined to the top several hundred ångströms and does not affect the bulk properties. The main disadvantage of this technique is that it requires a vacuum system, which increases the cost of operation. Thin polymer films with unique chemical and physical properties are produced by plasma polymerization

  8. Forces between hydrophilic surfaces adsorbed with apolipoprotein AII alpha helices.

    Science.gov (United States)

    Ramos, S; Campos-Terán, J; Mas-Oliva, J; Nylander, Tommy; Castillo, R

    2008-08-19

    To provide better understanding of how a protein secondary structure affects protein-protein and protein-surface interactions, forces between amphiphilic alpha-helical proteins (human apolipoprotein AII) adsorbed on a hydrophilic surface (mica) were measured using an interferometric surface force apparatus (SFA). Forces between surfaces with adsorbed layers of this protein are mainly composed of electrostatic double layer forces at large surface distances and of steric repulsive forces at small distances. We suggest that the amphiphilicity of the alpha-helix structure facilitates the formation of protein multilayers next to the mica surfaces. We found that protein-surface interaction is stronger than protein-protein interaction, probably due to the high negative charge density of the mica surface and the high positive charge of the protein at our experimental conditions. Ellipsometry was used to follow the adsorption kinetics of this protein on hydrophilic silica, and we observed that the adsorption rate is not only controlled by diffusion, but rather by the protein-surface interaction. Our results for dimeric apolipoprotein AII are similar to those we have reported for the monomeric apolipoprotein CI, which has a similar secondary structure but a different peptide sequence and net charge. Therefore, the observed force curves seem to be a consequence of the particular features of the amphiphilic alpha-helices.

  9. Review of hydrophilic PP membrane for organic waste removal

    Science.gov (United States)

    Ariono, Danu; Wardani, Anita Kusuma

    2017-05-01

    The acceleration of industrialization in developing countries has given an impact of environmental pollution rapidly, such as contamination of groundwater with organic waste. To solve this problem, some membrane techniques have been performed to remove organic waste from water, such as membrane contactors, membrane bioreactors, and supported liquid membranes. Polypropylene (PP) membrane is one of the promising candidates for these membrane processes due to its chemical stability, low cost, good mechanical resistance, and being easily available. However, different processes require membranes with different surface properties. Hydrophobic PP membranes with excellent chemical stability can be directly used in membrane contactors, in which the organic phase wets the porous membrane and slightly excessive pressure applied to the other phase. On the other hand, hydrophilization of PP membrane is necessary for some other processes, such as for fouling reduction on membrane bioreactors due to organic matters deposition. The aim of this paper is to give a brief overview of removal of organic waste by PP membrane. Moreover, the effects of PP surface hydrophilization on antifouling properties are also discussed.

  10. Stability of triglyceride liquid films on hydrophilic and hydrophobic glasses.

    Science.gov (United States)

    Vazquez, Rosa; Nogueira, Rui; Orfão, Marta; Mata, José Luís; Saramago, Benilde

    2006-07-01

    Wetting and dewetting of solid surfaces by oily fluids were investigated in terms of the stability of the liquid film formed between an air bubble and the solid surface. With the objective of understanding how molecules with low polarity but relatively complex molecular structure behave at the solid/liquid interface, three liquid triglycerides with different chain length and saturation were chosen, namely, tributyrin, tricaprylin, and triolein. Tributyrin and tricaprylin exist in milkfat while triolein is present in vegetable oils. The stability of the liquid films may be inferred from the shape of the disjoining pressure isotherms, which represent the dependence of the disjoining pressure on the film thickness. Disjoining pressure isotherms for films of the three triglycerides on hydrophilic and hydrophobic glasses were obtained using a recently developed apparatus, based on the interferometric technique. The experimental curves are compared with the theoretical predictions of London-Hamaker. The deviations between theory and experiment are interpreted in terms of a structural component of the disjoining pressure. All triglycerides form metastable films on both hydrophilic and hydrophobic glasses which means that for disjoining pressures higher than a critical value, pi(c), a wetting transition occurs and the film ruptures. The mechanisms for film rupture are discussed and a correlation between film stability and the apolar (Lifshitz-van der Waals) and the polar components of the spreading coefficient is proposed.

  11. Controlled effect of ultrasonic cavitation on hydrophobic/hydrophilic surfaces.

    Science.gov (United States)

    Belova, Valentina; Gorin, Dmitry A; Shchukin, Dmitry G; Möhwald, Helmuth

    2011-02-01

    Controlling cavitation at the solid surface is of increasing interest, as it plays a major role in many physical and chemical processes related to the modification of solid surfaces and formation of multicomponent nanoparticles. Here, we show a selective control of ultrasonic cavitation on metal surfaces with different hydrophobicity. By applying a microcontact printing technique we successfully formed hydrophobic/hydrophilic alternating well-defined microstructures on aluminium surfaces. Fabrication of patterned surfaces provides the unique opportunity to verify a model of heterogeneous nucleation of cavitation bubbles near the solid/water interface by varying the wettability of the surface, temperature and ultrasonic power. At the initial stage of sonication (up to 30 min), microjets and shock waves resulting from the collapsing bubbles preferably impact the hydrophobic surface, whereas the hydrophilic areas of the patterned Al remain unchanged. Longer sonication periods affect both surfaces. These findings confirm the expectation that higher contact angle causes a lower energy barrier, thus cavitation dominates at the hydrophobic surfaces. Experimental results are in good agreement with expectations from nucleation theory. This paper illustrates a new approach to ultrasound induced modification of solid surfaces resulting in the formation of foam-structured metal surfaces.

  12. Thermal boundary conductance of hydrophilic and hydrophobic ionic liquids

    Science.gov (United States)

    Oyake, Takafumi; Sakata, Masanori; Yada, Susumu; Shiomi, Junichiro

    2015-03-01

    A solid/liquid interface plays a critical role for understanding mechanisms of biological and physical science. Moreover, carrier density of the surface is dramatically enhanced by electric double layer with ionic liquid, salt in the liquid state. Here, we have measured the thermal boundary conductance (TBC) across an interface of gold thin film and ionic liquid by using time-domain thermoreflectance technique. Following the prior researches, we have identified the TBC of two interfaces. One is gold and hydrophilic ionic liquid, N,N-Diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate (DEME-BF4), which is a hydrophilic ionic liquid, and the other is N,N-Diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (DEME-TFSI), which is a hydrophobic ionic liquid. We found that the TBC between gold and DEME-TFIS (19 MWm-2K-1) is surprisingly lower than the interface between gold and DEME-BF4 (45 MWm-2K-1). With these data, the importance of the wetting angle and ion concentration for the thermal transport at the solid/ionic liquid interface is discussed. Part of this work is financially supported by Japan Society for the Promotion of Science (JSPS) and Japan Science and Technology Agency. The author is financially supported by JSPS Fellowship.

  13. Randomised clinical trial: mixed soluble/insoluble fibre vs. psyllium for chronic constipation.

    Science.gov (United States)

    Erdogan, A; Rao, S S C; Thiruvaiyaru, D; Lee, Y Y; Coss Adame, E; Valestin, J; O'Banion, M

    2016-07-01

    Fibre supplements are useful, but whether a plum-derived mixed fibre that contains both soluble and insoluble fibre improves constipation is unknown. To investigate the efficacy and tolerability of mixed soluble/insoluble fibre vs. psyllium in a randomized double-blind controlled trial. Constipated patients (Rome III) received mixed fibre or psyllium, 5 g b.d., for 4 weeks. Daily symptoms and stool habit were assessed using stool diary. Subjects with ≥1 complete spontaneous bowel movement/week above baseline for ≥2/4 weeks were considered responders. Secondary outcome measures included stool consistency, bowel satisfaction, straining, gas, bloating, taste, dissolvability and quality of life (QoL). Seventy-two subjects (mixed fibre = 40; psyllium = 32) were enrolled and two from psyllium group withdrew. The mean complete spontaneous bowel movement/week increased with both mixed fibre (P psyllium (P = 0.0002) without group difference. There were 30 (75%) responders with mixed fibre and 24 (75%) with psyllium (P = 0.9). Stool consistency increased (P = 0.04), straining (P = 0.006) and bloating scores decreased (P = 0.02) without group differences. Significantly more patients reported improvement in flatulence (53% vs. 25%, P = 0.01) and felt that mixed fibre dissolved better (P = 0.02) compared to psyllium. QoL improved (P = 0.0125) with both treatments without group differences. Mixed fibre and psyllium were equally efficacious in improving constipation and QoL. Mixed fibre was more effective in relieving flatulence, bloating and dissolved better. Mixed fibre is effective and well tolerated. © 2016 John Wiley & Sons Ltd.

  14. Activation of Transient Receptor Potential Ankyrin-1 by Insoluble Particulate Material and Association with Asthma.

    Science.gov (United States)

    Deering-Rice, Cassandra E; Shapiro, Darien; Romero, Erin G; Stockmann, Chris; Bevans, Tatjana S; Phan, Quang M; Stone, Bryan L; Fassl, Bernhard; Nkoy, Flory; Uchida, Derek A; Ward, Robert M; Veranth, John M; Reilly, Christopher A

    2015-12-01

    Inhaled irritants activate transient receptor potential ankyrin-1 (TRPA1), resulting in cough, bronchoconstriction, and inflammation/edema. TRPA1 is also implicated in the pathogenesis of asthma. Our hypothesis was that particulate materials activate TRPA1 via a mechanism distinct from chemical agonists and that, in a cohort of children with asthma living in a location prone to high levels of air pollution, expression of uniquely sensitive forms of TRPA1 may correlate with reduced asthma control. Variant forms of TRPA1 were constructed by mutating residues in known functional elements and corresponding to single-nucleotide polymorphisms in functional domains. TRPA1 activity was studied in transfected HEK-293 cells using allyl-isothiocynate, a model soluble electrophilic agonist; 3,5-ditert butylphenol, a soluble nonelectrophilic agonist and a component of diesel exhaust particles; and insoluble coal fly ash (CFA) particles. The N-terminal variants R3C and R58T exhibited greater, but not additive, activity with all three agonists. The ankyrin repeat domain-4 single nucleotide polymorphisms E179K and K186N exhibited decreased response to CFA. The predicted N-linked glycosylation site residues N747A and N753A exhibited decreased responses to CFA, which were not attributable to differences in cellular localization. The pore-loop residue R919Q was comparable to wild-type, whereas N954T was inactive to soluble agonists but not CFA. These data identify roles for ankyrin domain-4, cell surface N-linked glycans, and selected pore-loop domain residues in the activation of TRPA1 by insoluble particles. Furthermore, the R3C and R58T polymorphisms correlated with reduced asthma control for some children, which suggest that TRPA1 activity may modulate asthma, particularly among individuals living in locations prone to high levels of air pollution.

  15. Molecular and isotope constraints on the formation of the insoluble organic matter of carbonaceous meteorites

    Science.gov (United States)

    Derenne, Sylvie; Robert, François

    2017-04-01

    The origin of the insoluble organic matter (IOM) of the carbonaceous meteorites remains an unsolved issue despite major achievements in the knowledge of its chemical structure. The latter led us to propose a model for its molecular structure. Based on the relationship between the aromatic moieties of the macromolecular structure and their aliphatic linkages, it was recently suggested that, its synthesis has taken place in the gas phase of the disk surrounding the Sun in its early T-Tauri phase and that organic radicals have played a central role in this organo-synthesis. To test experimentally this pathway, we submitted short hydrocarbons (methane, pentane, octane) to a microwave plasma discharge so as to produce in situ CHx radicals. The black organic residue deposited contained both soluble and insoluble OM. The comparison at the molecular level between the thus synthesized IOM and that of meteorite led to strong similarities thus supporting the proposed pathway for its organo-synthesis. Moreover, in the meteorite IOM, systematic deuterium enrichment relative to the protosolar value is observed at the bulk sample scale and micrometer-sized grains exhibit dramatic enrichments in deuterium interpreted as a heritage of the interstellar medium or resulting from ion-molecule reactions taking place in the diffuse part of the solar disk. In the aforementioned synthesized IOM, NanoSIMS analyses revealed large variations at a sub-micrometric spatial resolution. They likely reflect the differences in the D/H ratios of the CHx radicals whose polymerization is at the origin of the IOM. These isotopic heterogeneities are commensurable with those observed in meteorite IOM. As a consequence, the appearance of organic radicals in the ionized regions of the T-Tauri solar disk may have triggered the formation of organic compounds. This laboratory synthesis thus shed a new light on the formation conditions and pathways of the IOM of carbonaceous chondrites.

  16. Protective value of immune responses developed in goats vaccinated with insoluble proteins from Sarcoptes Scabiei

    Directory of Open Access Journals (Sweden)

    Simson Tarigan

    2005-06-01

    Full Text Available Vaccines developed from certain membrane proteins lining the lumen of arthropod’s gut have been demonstrated effective in the control of some arthropod ectoparasites. A similar approach could also be applied to Sarcoptes scabiei since this parasite also ingests its host immunoglobulins. To evaluate immune protection of the membrane proteins, insoluble mite proteins were fractionated by successive treatment in the solutions of 1.14 M NaCl, 2% SB 3-14 Zwitterion detergent, 6 M urea, 6 M guanidine-HCl and 5% SDS. Five groups of goats (6 or 7 goats per group were immunised respectively with the protein fractions. Vaccination was performed 6 times, each with a dosage of 250 μg proteins, and 3 week intervals between vaccination. Group 6 (7 goats received PBS and adjuvant only, and served as an unvaccinated control. One week after the last vaccination, all goats were challenged with 2000 live mites on the auricles. The development of lesions were examined at 1 day, 2 days, and then every week from week 1 to 8. All animals were bled and weighed every week, and at the end of the experiment, skin scrapings were collected to determine the mite burden. Antibody responses induced by vaccination and challenge were examined by ELISA and Western blotting. This experiment showed that vaccination with the insoluble-protein fractions resulted in the development of high level of specific antibodies but the responses did not have any protective value. The severity of lesions and mite burden in the vaccinated animals were not different from those in the unvaccinated control.

  17. Solid intercalation to produce polymer/clay nanocomposites

    Science.gov (United States)

    Carreyette, Shuaijin Chen

    A review of recent literature and current knowledge relating to the development in polymer/clay nanocomposites has been presented. A novel method, solid intercalation, to produce polymer/clay nanocomposites is described based on two polymers, polyethylene oxide and polystyrene with two clays, hydrophilic clay G105 and organoclay 1.28. The clays used in the solid intercalation are selected based on the nanostructure, microstructure and thermal stability results. The polymers are selected based on their potential applications. The structures of the resultant materials are analysed and the possible mechanisms of the solid intercalation in different polymer/clay systems are presented. The experiment results show that the organoclay is more promising in obtaining a good dispersion and expansion of the clay layers in polymer matrices, especially at high clay loading. Hydrophilic clay can be well dispersed and expanded in the polyethylene oxide/clay system for clay contents below 10 wt%. A comparison between solid intercalation and solution synthesis is made for the polyethylene oxide/clay system. The structure diagrams for the corresponding method are illustrated. The nanocomposites produced by solid intercalation are composed of isolated polymer and intercalated/exfoliated polymer/clay structures, while those produced by solution synthesis are mainly composed of intercalated structures. Studies of the processing conditions of solid intercalation of the PEO/G105 clay system were carried out. The results show that the moisture level is critical in producing the composites by solid intercalation. There are two possible mechanisms for producing the composites - the melt and flow of the polymer into the clay galleries or the formation of the polymer solution and flow into the clay galleries. The results also show that high pressure and temperature improve the melt and flow of the polymer in solid intercalation which encourages more intercalation to take place. The mechanical

  18. Improvement of the surface hydrophilic properties of naproxen particles with addition of hydroxypropylmethyl cellulose and sodium dodecyl sulphate: In vitro and in vivo studies.

    Science.gov (United States)

    García-Herrero, Víctor; Torrado, Carlos; García-Rodríguez, Juan José; López-Sánchez, Alicia; Torrado, Susana; Torrado-Santiago, Santiago

    2017-08-30

    In this study, a new surface-modified naproxen was developed to enhance brain concentration in acute migraine treatment. Fast-dissolving naproxen granules were made by mixing hydroxypropylmethylcellulose (HPMC) sodium dodecyl sulphate (SDS) and sodium croscarmellose with micronized naproxen particles. The aim of this study was to evaluate the effect of adding proportions of SDS to the HPMC film caused changes in the polymer chains of the HPMC, producing a new hydrophilic HPMC-SDS structure. These formulations with different HPMC/SDS ratios were characterised using electron microscopy (SEM), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). SDS 10% (w/w) produced a highly hydrophilic HPMC-SDS structure on the surface of the naproxen microparticles. The fast dissolution granules (SF-10%) showed a significant improvement in the dissolution rate of naproxen. Pharmacokinetic studies were conducted with mice, showing an improvement of Cmax (1.38 and 1.41-fold) and AUC0-2h (30% and 10% higher) for plasma and brain samples compared to the reference naproxen suspension. The faster Tmax ratio for SF-10% may be related to increased hydration in the gastrointestinal environment, enabling the drug to permeate the gastrointestinal hydration layer more easily due to the presence of the hydrophilic HPMC-SDS structure in the formulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Comparison of the fouling release properties of hydrophobic fluorinated and hydrophilic PEGylated block copolymer surfaces: attachment strength of the diatom Navicula and the green alga Ulva.

    Science.gov (United States)

    Krishnan, Sitaraman; Wang, Nick; Ober, Christopher K; Finlay, John A; Callow, Maureen E; Callow, James A; Hexemer, Alexander; Sohn, Karen E; Kramer, Edward J; Fischer, Daniel A

    2006-05-01

    To understand the role of surface wettability in adhesion of cells, the attachment of two different marine algae was studied on hydrophobic and hydrophilic polymer surfaces. Adhesion of cells of the diatom Navicula and sporelings (young plants) of the green macroalga Ulva to an underwater surface is mainly by interactions between the surface and the adhesive exopolymers, which the cells secrete upon settlement and during subsequent colonization and growth. Two types of block copolymers, one with poly(ethylene glycol) side-chains and the other with liquid crystalline, fluorinated side-chains, were used to prepare the hydrophilic and hydrophobic surfaces, respectively. The formation of a liquid crystalline smectic phase in the latter inhibited molecular reorganization at the surface, which is generally an issue when a highly hydrophobic surface is in contact with water. The adhesion strength was assessed by the fraction of settled cells (Navicula) or biomass (Ulva) that detached from the surface in a water flow channel with a wall shear stress of 53 Pa. The two species exhibited opposite adhesion behavior on the same sets of surfaces. While Navicula cells released more easily from hydrophilic surfaces, Ulva sporelings showed higher removal from hydrophobic surfaces. This highlights the importance of differences in cell-surface interactions in determining the strength of adhesion of cells to substrates.

  20. Rheological, mucoadhesive and release properties of Carbopol gels in hydrophilic cosolvents.

    Science.gov (United States)

    Bonacucina, Giulia; Martelli, Sante; Palmieri, Giovanni F

    2004-09-10

    Carbopol is one of the most common thickening agent for water phases. It is used after neutralisation and its rheological properties in the aqueous medium are well known. The aim of this work was to investigate the gelation properties of Carbopol 971 e 974 polymeric systems in water-miscible cosolvents such as glycerine and PEG 400. Since in these cosolvents, carboxypolymethylene precipitates after neutralisation with a base, then the attention was pointed out of the gelation properties of the different systems at increasing temperature, in order to obtain Carbopols gels avoiding neutralisation and, at the same time, making possible the dissolution in these gels of insoluble or poorly soluble water drugs. Rheological properties of PEG 400 and glycerine samples were compared with similar systems in water by performing oscillatory analyses and measuring the main rheological parameters, G', G" and delta. The results obtained showed that Carbopol 971 and 974 in PEG 400 gave rise after heating to gels that show a satisfactory rheological behaviour. The elastic modulus is greater than the viscous one showing a remarkable elastic character of these samples and the performed frequency sweeps show a typical spectrum of a "gel-like" structure. Being Carbopols well-known mucoadhesive polymers, gels adhesive properties were studied using the ex vivo method. Then, the possible cutaneous irritation were also tested using the in vivo method (Draize test). No signs of cutaneous irritation and good mucoadhesive properties were obtained for the PEG 400 and water gels of Carbopol 974 prepared by heating. After rheological and mucoadhesive properties were set, paracetamol as a model drug was then inserted in the composition of the gels and the release characteristics were defined. Dissolution tests pointed out the greater release control properties of PEG 400-Carbopol 971 samples. These studies showed PEG 400-Carbopol systems as a first-rate alternative to traditional water gels.

  1. Forecasting of the content of the insoluble residue in clay layers of productive beds of the Verkhnekamskoe salt deposit

    Directory of Open Access Journals (Sweden)

    E. O. Bayandina

    2015-03-01

    Full Text Available Using data from the exploration drilling at the mines BKPRU-2 and BKPRU-3 of JSC Uralkali, the relationship equations between the content of insoluble residue in the productive sylvinite beds and thick interbedded clay layers at their top referred to as «korjʼs» are worked out. Knowledge of composition and thickness of clay layers is very important for rockfall protection during mining work. The results of analysis of drilling data are often not reliable because of the losses of clay material in the extracted core. The resulting equations are recommended for forecastingof insoluble residue in «korjʼs» of those beds.

  2. Enzymatic Xylose Release from Pretreated Corn Bran Arabinoxylan: Differential Effects of Deacetylation and Deferuloylation on Insoluble and Soluble Substrate Fractions

    DEFF Research Database (Denmark)

    Agger, Jane; Viksø-Nielsen, Ander; Meyer, Anne S.

    2010-01-01

    In the present work enzymatic hydrolysis of arabinoxylan from pretreated corn bran (190 °C, 10 min) was evaluated by measuring the release of xylose and arabinose after treatment with a designed minimal mixture of monocomponent enzymes consisting of α-l-arabinofuranosidases, an endoxylanase......, and a β-xylosidase. The pretreatment divided the corn bran material 50:50 into soluble and insoluble fractions having A:X ratios of 0.66 and 0.40, respectively. Addition of acetyl xylan esterase to the monocomponent enzyme mixture almost doubled the xylose release from the insoluble substrate fraction...

  3. Behavior of insoluble particles during parabolic flight solidification processing of Fe-C-Si and Fe-C-V alloys

    Science.gov (United States)

    Stefanescu, D. M.; Fiske, M. R.; Curreri, P. A.

    1986-01-01

    In a high-g rapid solidification environment, Fe-base alloy insoluble particles at the solidification interface may be pushed ahead of the interface or may be trapped in the solid, depending on the correlation of various interface energies, the solidification rates, and the Stokes force; particle agglomeration due to buoyancy-driven convection further complicates the problem. Attention is presently given to results obtained for directionally solidified Fe-C-Si and Fe-C-V alloys during parabolic low-g flight and ground experiments. In these systems, graphite and vanadium carbide can be considered to be the insoluble particles.

  4. Insoluble Fiber in Young Barley Leaf Suppresses the Increment of Postprandial Blood Glucose Level by Increasing the Digesta Viscosity

    OpenAIRE

    Takano, Akira; Kamiya, Tomoyasu; Tomozawa, Hiroshi; Ueno, Shiori; Tsubata, Masahito; Ikeguchi, Motoya; Takagaki, Kinya; Okushima, Ayaka; Miyata, Yu; Tamaru, Shizuka; Tanaka, Kazunari; Takahashi, Toru

    2013-01-01

    Barley (Hordeum vulgare L.) is a well-known cereal plant. Young barley leaf is consumed as a popular green-colored drink, which is named ?Aojiru? in Japan. We examined the effects of barley leaf powder (BLP) and insoluble fibers derived from BLP on postprandial blood glucose in rats and healthy Japanese volunteers. BLP and insoluble fibers derived from BLP suppressed the increment of postprandial blood glucose levels in rats (P < 0.01), and increased the viscosity of their digesta. The insolu...

  5. Nanoparticle and Gelation Stabilized Functional Composites of an Ionic Salt in a Hydrophobic Polymer Matrix

    Science.gov (United States)

    Kanyas, Selin; Aydın, Derya; Kizilel, Riza; Demirel, A. Levent; Kizilel, Seda

    2014-01-01

    Polymer composites consisted of small hydrophilic pockets homogeneously dispersed in a hydrophobic polymer matrix are important in many applications where controlled release of the functional agent from the hydrophilic phase is needed. As an example, a release of biomolecules or drugs from therapeutic formulations or release of salt in anti-icing application can be mentioned. Here, we report a method for preparation of such a composite material consisted of small KCOOH salt pockets distributed in the styrene-butadiene-styrene (SBS) polymer matrix and demonstrate its effectiveness in anti-icing coatings. The mixtures of the aqueous KCOOH and SBS-cyclohexane solutions were firstly stabilized by adding silica nanoparticles to the emulsions and, even more, by gelation of the aqueous phase by agarose. The emulsions were observed in optical microscope to check its stability in time and characterized by rheological measurements. The dry composite materials were obtained via casting the emulsions onto the glass substrates and evaporations of the organic solvent. Composite polymer films were characterized by water contact angle (WCA) measurements. The release of KCOOH salt into water and the freezing delay experiments of water droplets on dry composite films demonstrated their anti-icing properties. It has been concluded that hydrophobic and thermoplastic SBS polymer allows incorporation of the hydrophilic pockets/phases through our technique that opens the possibility for controlled delivering of anti-icing agents from the composite. PMID:24516593

  6. Nanoparticle and gelation stabilized functional composites of an ionic salt in a hydrophobic polymer matrix.

    Directory of Open Access Journals (Sweden)

    Selin Kanyas

    Full Text Available Polymer composites consisted of small hydrophilic pockets homogeneously dispersed in a hydrophobic polymer matrix are important in many applications where controlled release of the functional agent from the hydrophilic phase is needed. As an example, a release of biomolecules or drugs from therapeutic formulations or release of salt in anti-icing application can be mentioned. Here, we report a method for preparation of such a composite material consisted of small KCOOH salt pockets distributed in the styrene-butadiene-styrene (SBS polymer matrix and demonstrate its effectiveness in anti-icing coatings. The mixtures of the aqueous KCOOH and SBS-cyclohexane solutions were firstly stabilized by adding silica nanoparticles to the emulsions and, even more, by gelation of the aqueous phase by agarose. The emulsions were observed in optical microscope to check its stability in time and characterized by rheological measurements. The dry composite materials were obtained via casting the emulsions onto the glass substrates and evaporations of the organic solvent. Composite polymer films were characterized by water contact angle (WCA measurements. The release of KCOOH salt into water and the freezing delay experiments of water droplets on dry composite films demonstrated their anti-icing properties. It has been concluded that hydrophobic and thermoplastic SBS polymer allows incorporation of the hydrophilic pockets/phases through our technique that opens the possibility for controlled delivering of anti-icing agents from the composite.

  7. Incorporation of Polymers into Calcined Clays as Improved Thermal Insulating Materials for Construction

    Directory of Open Access Journals (Sweden)

    Serina Ng

    2017-01-01

    Full Text Available Calcined clay is a Type Q supplementary cementing material according to EN197-1:2000. It possesses lower thermal conductivity than cement. To further improve its thermal insulation property, polymer-calcined clay complexes (PCCs were produced in a one-pot synthesis. Two contrasting polymers, polystyrene (PS and polyethylene glycol (PEG, were employed. The hydrophilicity of the polymers influenced the thermal conductivity of PCC. Hydrophilic PEG entrapped more water molecules on clay layers than the hydrophobic PS, making PEG-PCC more thermally conducting than PS-PCC. Contaminants in calcined clays played a role in affecting the overall thermal conductivity. PCC can improve thermal insulation properties for future construction applications.

  8. Phthalocyanine polymers

    Science.gov (United States)

    Achar, B. N.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1985-01-01

    A method of forming 4,4',4'',4''' -tetraamino phthalocyanines involves reducing 4,4',4'',4''' -tetranitro phthalocyanines, polymerizing the metal tetraamino phthalocyanines with a tetracarboxylic dianhydride (preferably aromatic) or copolymerizing with a tetracarboxylic dianhydride and a diamine (preferably also aromatic) to produce amic acids which are then dehydrocyclized to imides. Thermally and oxidatively stable polymers result which form tough, flexible films, varnishes, adhesives, and fibers.

  9. Polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Naik, Sanjeev

    2017-08-22

    The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.

  10. Water interaction with hydrophobic and hydrophilic soot particles.

    Science.gov (United States)

    Popovicheva, Olga; Persiantseva, Natalia M; Shonija, Natalia K; DeMott, Paul; Koehler, Kirsten; Petters, Markus; Kreidenweis, Sonia; Tishkova, Victoria; Demirdjian, Benjamin; Suzanne, Jean

    2008-05-07

    The interaction of water with laboratory soots possessing a range of properties relevant for atmospheric studies is examined by two complementary methods: gravimetrical measurement of water uptake coupled with chemical composition and porosity analysis and HTDMA (humidified tandem differential mobility analyzer) inference of water uptake accompanied by separate TEM (transmission electron microscopy) analysis of single particles. The first method clarifies the mechanism of water uptake for bulk soot and allows the classification of soot with respect to its hygroscopicity. The second method highlights the dependence of the soot aerosol growth factor on relative humidity (RH) for quasi-monodisperse particles. Hydrophobic and hydrophilic soot are qualitatively defined by their water uptake and surface polarity: laboratory soot particles are thus classified from very hydrophobic to very hydrophilic. Thermal soot particles produced from natural gas combustion are classified as hydrophobic with a surface of low polarity since water is found to cover only half of the surface. Graphitized thermal soot particles are proposed for comparison as extremely hydrophobic and of very low surface polarity. Soot particles produced from laboratory flame of TC1 aviation kerosene are less hydrophobic, with their entire surface being available for statistical monolayer water coverage at RH approximately 10%. Porosity measurements suggest that, initially, much of this surface water resides within micropores. Consequently, the growth factor increase of these particles to 1.07 at RH > 80% is attributed to irreversible swelling that accompanies water uptake. Hysteresis of adsorption/desorption cycles strongly supports this conclusion. In contrast, aircraft engine soot, produced from burning TC1 kerosene in a gas turbine engine combustor, has an extremely hydrophilic surface of high polarity. Due to the presence of water soluble organic and inorganic material it can be covered by many water

  11. High Performance Thin-film Composite Membranes with Mesh-Reinforced Hydrophilic Sulfonated Polyphenylenesulfone (sPPSU) Substrates for Osmotically Driven Processes

    KAUST Repository

    Han, Gang

    2015-12-17

    We have for the first time combined the strength of hydrophilic sulfonated material and thin woven open-mesh via a continuous casting process to fabricate mesh-reinforced ultrafiltration (UF) membrane substrates with desirable structure and morphology for the development of high-performance thin-film composite (TFC) osmosis membranes. A new sulfonated polyphenylenesulfone (sPPSU) polymer with super-hydrophilic nature is used as the substrate material, while a hydrophilic polyester (PET) open-mesh with a small thickness of 45 μm and an open area of 44.5% is employed as the reinforcing fabric during membrane casting. The newly developed sPPSU-TFC membranes not only exhibit a fully sponge-like cross-section morphology, but also possess excellent water permeability (A=3.4–3.7 L m−2 h−1 bar−1) and selectivity toward NaCl (B=0.10–0.23 L m−2 h−1). Due to the hydrophilic nature and low membrane thickness of 53–67 μm, the PET-woven reinforced sPPSU substrates have remarkably small structural parameters (S) of less than 300 μm. The sPPSU-TFC membranes thereby display impressive water fluxes (Jw) of 69.3–76.5 L m−2 h−1 and 38.7–47.0 L m−2 h−1 against a deionized water feed using 2 M NaCl as the draw solution under pressure retarded osmosis (PRO) and forward osmosis (FO) modes, respectively. This performance surpasses the state-of-the-art commercially available FO membranes. The sPPSU-TFC membranes also show exciting performance for synthetic seawater (3.5 wt% NaCl) desalination and water reclamation from real municipal wastewater. The newly developed PET-woven sPPSU-TFC membranes may have great potential to become a new generation membrane for osmotically driven processes.

  12. Why do proteins aggregate? “Intrinsically insoluble proteins” and “dark mediators” revealed by studies on “insoluble proteins” solubilized in pure water [v1; ref status: indexed, http://f1000r.es/z0

    Directory of Open Access Journals (Sweden)

    Jianxing Song

    2013-03-01

    Full Text Available In 2008, I reviewed and proposed a model for our discovery in 2005 that unrefoldable and insoluble proteins could in fact be solubilized in unsalted water. Since then, this discovery has offered us and other groups a powerful tool to characterize insoluble proteins, and we have further addressed several fundamental and disease-relevant issues associated with this discovery. Here I review these results, which are conceptualized into several novel scenarios. 1 Unlike 'misfolded proteins', which still retain the capacity to fold into well-defined structures but are misled to 'off-pathway' aggregation, unrefoldable and insoluble proteins completely lack this ability and will unavoidably aggregate in vivo with ~150 mM ions, thus designated as 'intrinsically insoluble proteins (IIPs' here. IIPs may largely account for the 'wastefully synthesized' DRiPs identified in human cells. 2 The fact that IIPs including membrane proteins are all soluble in unsalted water, but get aggregated upon being exposed to ions, logically suggests that ions existing in the background play a central role in mediating protein aggregation, thus acting as 'dark mediators'. Our study with 14 salts confirms that IIPs lack the capacity to fold into any well-defined structures. We uncover that salts modulate protein dynamics and anions bind proteins with high selectivity and affinity, which is surprisingly masked by pre-existing ions. Accordingly, I modified my previous model. 3 Insoluble proteins interact with lipids to different degrees. Remarkably, an ALS-causing P56S mutation transforms the β-sandwich MSP domain into a helical integral membrane protein. Consequently, the number of membrane-interacting proteins might be much larger than currently recognized. To attack biological membranes may represent a common mechanism by which aggregated proteins initiate human diseases. 4 Our discovery also implies a solution to the 'chicken-and-egg paradox' for the origin of primitive

  13. Enzymatic synthesis of a 6-sialyl lactose analogue using a pH-responsive water-soluble polymer support.

    Science.gov (United States)

    Wang, Wenjun; Li, Lei; Jin, Chen; Niu, Yujie; Li, Sen; Ma, Ji; Li, Linfeng; Liu, Yu; Cai, Li; Zhao, Wei; Wang, Peng George

    2011-09-01

    The Letter describes a strategy for the enzymatic synthesis of glycans based on a pH-responsive water-soluble polymer. In neutral condition, the polymer is water-soluble and convenient for in-solution enzymatic synthesis, whereas in acidic condition (pH lower than 4.0), the polymer disconnects with the product and becomes insoluble, which can be easily removed. A 6-Sialyl lactose analogue was synthesized as a model reaction using this approach. Copyright © 2011. Published by Elsevier Ltd.

  14. The effect of contact angles and capillary dimensions on the burst frequency of super hydrophilic and hydrophilic centrifugal microfluidic platforms, a CFD study.

    Directory of Open Access Journals (Sweden)

    Amin Kazemzadeh

    Full Text Available This paper employs the volume of fluid (VOF method to numerically investigate the effect of the width, height, and contact angles on burst frequencies of super hydrophilic and hydrophilic capillary valves in centrifugal microfluidic systems. Existing experimental results in the literature have been used to validate the implementation of the numerical method. The performance of capillary valves in the rectangular and the circular microfluidic structures on super hydrophilic centrifugal microfluidic platforms is studied. The numerical results are also compared with the existing theoretical models and the differences are discussed. Our experimental and computed results show a minimum burst frequency occurring at square capillaries and this result is useful for designing and developing more sophisticated networks of capillary valves. It also predicts that in super hydrophilic microfluidics, the fluid leaks consistently from the capillary valve at low pressures which can disrupt the biomedical procedures in centrifugal microfluidic platforms.

  15. The effect of contact angles and capillary dimensions on the burst frequency of super hydrophilic and hydrophilic centrifugal microfluidic platforms, a CFD study.

    Science.gov (United States)

    Kazemzadeh, Amin; Ganesan, Poo; Ibrahim, Fatimah; He, Shuisheng; Madou, Marc J

    2013-01-01

    This paper employs the volume of fluid (VOF) method to numerically investigate the effect of the width, height, and contact angles on burst frequencies of super hydrophilic and hydrophilic capillary valves in centrifugal microfluidic systems. Existing experimental results in the literature have been used to validate the implementation of the numerical method. The performance of capillary valves in the rectangular and the circular microfluidic structures on super hydrophilic centrifugal microfluidic platforms is studied. The numerical results are also compared with the existing theoretical models and the differences are discussed. Our experimental and computed results show a minimum burst frequency occurring at square capillaries and this result is useful for designing and developing more sophisticated networks of capillary valves. It also predicts that in super hydrophilic microfluidics, the fluid leaks consistently from the capillary valve at low pressures which can disrupt the biomedical procedures in centrifugal microfluidic platforms.

  16. Transforming plastic surfaces with electrophilic backbones from hydrophobic to hydrophilic.

    Science.gov (United States)

    Kim, Samuel; Bowen, Raffick A R; Zare, Richard N

    2015-01-28

    We demonstrate a simple nonaqueous reaction scheme for transforming the surface of plastics from hydrophobic to hydrophilic. The chemical modification is achieved by base-catalyzed trans-esterification with polyols. It is permanent, does not release contaminants, and causes no optical or mechanical distortion of the plastic. We present contact angle measurements to show successful modification of several types of plastics including poly(ethylene terephthalate) (PET) and polycarbonate (PC). Its applicability to blood analysis is explored using chemically modified PET blood collection tubes and found to be quite satisfactory. We expect this approach will reduce the cost of manufacturing plastic devices with optimized wettability and can be generalized to other types of plastic materials having an electrophilic linkage as its backbone.

  17. Hydrophilic and size-controlled graphene nanopores for protein detection

    Science.gov (United States)

    Goyal, Gaurav; Bok Lee, Yong; Darvish, Armin; Ahn, Chi Won; Kim, Min Jun

    2016-12-01

    This paper describes a general approach for transferring clean single-layer graphene onto silicon nitride nanopore devices and the use of the electron beam of a transmission electron microscope (TEM) to drill size-controlled nanopores in freely suspended graphene. Besides nanopore drilling, we also used the TEM to heal and completely close the unwanted secondary holes formed by electron beam damage during the drilling process. We demonstrate electron beam assisted shrinking of irregularly shaped 40-60 nm pores down to 2 nm, exhibiting an exquisite control of graphene nanopore diameter. Our fabrication workflow also rendered graphene nanopores hydrophilic, allowing easy wetting and use of the pores for studying protein translocation and protein-protein interaction with a high signal to noise ratio.

  18. Enrichment of deuterium oxide at hydrophilic interfaces in aqueous solutions.

    Science.gov (United States)

    Stålgren, Johan J R; Boschkova, Katrin; Ericsson, Jan-Christer; Frank, Curtis W; Knoll, Wolfgang; Satija, Sushil; Toney, Michael F

    2007-11-20

    The structure of water at aqueous interfaces is of the utmost importance in biology, chemistry, and geology. We use neutron reflectivity and quartz crystal microbalance to probe an interface between hydrophilic quartz and bulk liquid solutions of H2O/D2O mixtures. We find that near the interface the neutron scattering length density is larger than in the bulk solution and there is an excess adsorbed mass. We interpret this as showing that there is a region adjacent to the quartz that is enriched in D2O and extends 5-10 nm into the solution. This suggests caution when interpreting results where D2O is substituted for H2O in aqueous interfacial chemistry.

  19. Separation of carbohydrates using hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Fu, Qing; Liang, Tu; Li, Zhenyu; Xu, Xiaoyong; Ke, Yanxiong; Jin, Yu; Liang, Xinmiao

    2013-09-20

    A strategy was developed to rapidly evaluate chromatographic properties of hydrophilic interaction chromatography (HILIC) columns for separating carbohydrates. Seven HILIC columns (Silica, Diol, TSK Amide-80, XAmide, Click Maltose, Click β-CD, and Click TE-Cys columns) were evaluated by using three monosaccharide and seven disaccharides as probes. The influence of column temperature on the peak shape and tautomerization of carbohydrates, as well as column selectivity were investigated. The influence of surface charge property on the retention was also studied by using glucose, glucuronic acid, and glucosamine, which indicated that buffer salt concentration and pH value in mobile phase was necessary to control the ionic interactions between ionic carbohydrates and HILIC columns. According to evaluation results, the XAmide column was selected as an example to establish experimental schemes for separation of complex mixtures of oligosaccharide. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. [Chemical characteristics and insoluble particulates' surface morphology of a snowfall process in the southeastern suburb of Urumqi].

    Science.gov (United States)

    Lu, Hui; Wei, Wen-Shou; Cui, Cai-Xia; He, Qing; Wang, Yao

    2014-04-01

    In order to understand the composition and potential pollution of metal elements in precipitation in the southeastern suburb of Urumqi on February 21 to 23, 2012, soluble elements were determined by inductively coupled plasma mass spectrometry (ICP-MS); in addition, energy spectrum and morphological analysis were made for insoluble particulates. The results showed that the content of toxic heavy metals in snowfall was a little high; and the enrichment factors of Se, As and Cd were 124.65, 57.69 and 36.70, respectively, showing a typical coal pollution characteristic. The back trajectory cluster analysis suggested that the coal fly ash of snowfall mainly induced by air masses originated from the coal-fire power plant in the Southwestern sampling site. Morphology analyses conducted under an scan electron microscope demonstrated fly ash coming from coal burning process and irregular mineral are in the majority of insoluble particulates in snowfall, soot aggregates were compact, when the soot was wetted (the hygroscopic behaviour), and the morphology changed further. Insoluble particulates of the southeastern suburb of Urumqi were coal fly ash and insoluble soil minerals.

  1. Hydroxyl radical production by a heterogeneous Fenton reaction supported in insoluble tannin from bark of Pinus radiata.

    Science.gov (United States)

    Romero, Romina; Contreras, David; Segura, Cristina; Schwederski, Brigitte; Kaim, Wolfgang

    2017-03-01

    Fenton reactions driven by dihydroxybenzenes (DHBs) have been used for pollutant removal via advanced oxidation processes (AOPs), but such systems have the disadvantage of DHB release into the aqueous phase. In this work, insoluble tannins from bark can be used to drive Fenton reactions and as a heterogeneous support. This avoids the release of DHBs into the aqueous phase and can be used for AOPs. The production of ·OH was investigated using a spin-trapping electron paramagnetic resonance technique (5-dimethyl-1-pyrroline-N-oxide/·OH) in the first minute of the reaction and a high-performance liquid chromatography-fluorescence technique (coumarin/7-hydroxycoumarin) for 20 min. The ·OH yield achieved using insoluble tannins from Pinus radiata bark was higher than that achieved using catechin to drive the Fenton reaction. The Fenton-like system driven by insoluble tannins achieved 92.6 ± 0.3 % degradation of atrazine in 30 min. The degradation kinetics of atrazine was linearly correlated with ·OH production. The increased reactivity in ·OH production and insolubility of the ligand are promising for the development of a new technique for degradation of pollutants in wastewater using heterogeneous Fenton systems.

  2. Custom fabrication of biomass containment devices using 3-D printing enables bacterial growth analyses with complex insoluble substrates.

    Science.gov (United States)

    Nelson, Cassandra E; Beri, Nina R; Gardner, Jeffrey G

    2016-11-01

    Physiological studies of recalcitrant polysaccharide degradation are challenging for several reasons, one of which is the difficulty in obtaining a reproducibly accurate real-time measurement of bacterial growth using insoluble substrates. Current methods suffer from several problems including (i) high background noise due to the insoluble material interspersed with cells, (ii) high consumable and reagent cost and (iii) significant time delay between sampling and data acquisition. A customizable substrate and cell separation device would provide an option to study bacterial growth using optical density measurements. To test this hypothesis we used 3-D printing to create biomass containment devices that allow interaction between insoluble substrates and microbial cells but do not interfere with spectrophotometer measurements. Evaluation of materials available for 3-D printing indicated that UV-cured acrylic plastic was the best material, being superior to nylon or stainless steel when examined for heat tolerance, reactivity, and ability to be sterilized. Cost analysis of the 3-D printed devices indicated they are a competitive way to quantitate bacterial growth compared to viable cell counting or protein measurements, and experimental conditions were scalable over a 100-fold range. The presence of the devices did not alter growth phenotypes when using either soluble substrates or insoluble substrates. We applied biomass containment to characterize growth of Cellvibrio japonicus on authentic lignocellulose (non-pretreated corn stover), and found physiological evidence that xylan is a significant nutritional source despite an abundance of cellulose present. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. A novel strategy to produce highly stable and transparent aqueous 'nanosolutions' of water-insoluble drug molecules

    Science.gov (United States)

    Wang, Jie-Xin; Zhang, Zhi-Bing; Le, Yuan; Zhao, Hong; Chen, Jian-Feng

    2011-07-01

    A surprisingly large proportion of new drug candidates emerging from drug discovery programmes are water-insoluble and, as a result, have poor oral bioavailability. To overcome insolubility, the drug particles are usually dispersed in a medium during product formation, but large particles that are formed may affect product performance and safety. Many techniques have been used to produce nanodispersions—dispersions with nanometre-scale dimensions—that have properties similar to solutions. However, making nanodispersions requires complex processing, and it is difficult to achieve stability over long periods. In this paper, we report a generic method for preparing drug nanoparticles with a combination of antisolvent precipitation in the presence of water-soluble matrices and spray-drying. The spray-dried powder composites (solid dispersion) are microspherical, highly stable and thus form transparent nanodispersions or so-called 'nanosolutions' of water-insoluble drug when simply added to water. Aqueous nanodispersions of silybin (a kind of water-insoluble drug for liver protection) with an average size of 25 nm produced with this approach display a 10 times faster dissolution rate than that of raw drug. This has great potential to offer a novel solution for innovative drugs of the future.

  4. Iron(III) chelating resins. VI. Stability constants of iron(III)-ligand complexes on insoluble polymeric matrices

    NARCIS (Netherlands)

    Feng, M.H.; Feng, Minhua; van der Does, L.; Bantjes, A.; Bantjes, Adriaan

    1995-01-01

    A method is presented for the determination of stability constants of iron(III)-ligand complexes on insoluble polymeric matrices based on a competition chelation reaction for iron(III) of the resin with a soluble chelator. Stability constants (K') were calculated for iron(III)-ligand complexes on

  5. Structural and physico-chemical properties of insoluble rice bran fiber: effect of acid–base induced modifications

    Science.gov (United States)

    The structural modifications of insoluble rice bran fiber (IRBF) by sequential regimes of sulphuric acid (H2SO4) and their effects on the physicochemical attributes were studied. The increment of H2SO4 concentration resulted in decreased water holding capacity that ultimately enhanced the oil bindin...

  6. Staphylococcus epidermidis adhesion on hydrophobic and hydrophilic textured biomaterial surfaces.

    Science.gov (United States)

    Xu, Li-Chong; Siedlecki, Christopher A

    2014-06-01

    It is of great interest to use nano- or micro-structured surfaces to inhibit microbial adhesion and biofilm formation and thereby to prevent biomaterial-associated infection, without modification of the surface chemistry or bulk properties of the materials and without use of the drugs. Our previous study showed that a submicron textured polyurethane surface can inhibit staphylococcal bacterial adhesion and biofilm formation. To further understand the effect of the geometry of textures on bacterial adhesion as well as the underlying mechanism, in this study, submicron and micron textured polyurethane surfaces featuring ordered arrays of pillars were fabricated and modified to have different wettabilities. All the textured surfaces were originally hydrophobic and showed significant reductions in Staphylococcus epidermidis RP62A adhesion in phosphate buffered saline or 25% platelet poor plasma solutions under shear, as compared to smooth surfaces. After being subjected to an air glow discharge plasma treatment, all polyurethane surfaces were modified to hydrophilic, and reductions in bacterial adhesion on surfaces were subsequently found to be dependent on the size of the patterns. The submicron patterned surfaces reduced bacterial adhesion, while the micron patterned surfaces led to increased bacterial adhesion. The extracellular polymeric substances (EPS) from the S. epidermidis cell surfaces were extracted and purified, and were coated on a glass colloidal surface so that the adhesion force and separation energy in interactions of the EPS and the surface could be measured by colloidal probe atomic force microscopy. These results were consistent with the bacterial adhesion observations. Overall, the data suggest that the increased surface hydrophobicity and the decreased availability of the contact area contributes to a reduction in bacterial adhesion to the hydrophobic textured surfaces, while the availability of the contact area is the primary determinant factor

  7. Effect of hydrophilic defects on water transport in MFI zeolites.

    Science.gov (United States)

    Humplik, Thomas; Raj, Rishi; Maroo, Shalabh C; Laoui, Tahar; Wang, Evelyn N

    2014-06-10

    The subnanometer pore structure of zeolites and other microporous materials has been proposed to act as a molecular sieve for various water separation technologies. However, due to the increased interaction between the solid and water in these nanoconfined spaces, it is unclear which type of interface, be it hydrophilic or hydrophobic, offers an advantageous medium for enhancing transport properties. In this work, we probe the role of hydrophilic defects on the transport of water inside the microporous hydrophobic MFI zeolite pore structure via combined sorption and high-pressure infiltration experiments. While the inclusion of defects was observed to increase the amount of water within the zeolite pore network by up to 7 times at the saturation pressure, the diffusivity of this infiltrated water was lowered by up to 2 orders of magnitude in comparison to that of water within the nearly defect-free hydrophobic MFI zeolite. Subsequently, the permeability of water within the more defective MFI zeolite was an order of magnitude lower than that of the nearly defect-free zeolite. The results from these experiments suggest that the intrinsic hydrophobic pore structure of MFI zeolites can facilitate faster water transport due to the decreased attraction between the water and the defect-free surface. While the strong attraction of water to the defects allows for water to infiltrate the porous network at lower pressures, the results suggest that this strong attraction decreases the mobility of the infiltrated water. The insights gained from this study can be utilized to improve the design of future membranes for water desalination and other separation techniques.

  8. Wetting behavior on hybrid surfaces with hydrophobic and hydrophilic properties

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Chun-Wei [Dept. of Mechanical Engineering, Texas A and M University, College Station, TX 77843 (United States); Alvarado, Jorge L., E-mail: Alvarado@entc.tamu.edu [Dept. of Engineering Technology and Industrial Distribution, Texas A and M University, College Station, TX 77843 (United States); Marsh, Charles P. [ERDC – Construction Engineering Research Laboratory, 2902 Newmark Dr., Champaign, IL 61826 (United States); Dept. of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801 (United States); Jones, Barclay G. [Dept. of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801 (United States); Collins, Michael K. [ERDC – Construction Engineering Research Laboratory, 2902 Newmark Dr., Champaign, IL 61826 (United States); Dept. of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801 (United States)

    2014-01-30

    Hybrid surfaces consisting of a micropillar array of hydrophobic and hydrophilic sites were designed and fabricated to understand the effects of their unique surface morphology and chemistry on droplet condensation. Droplet impingement experiments have revealed that hybrid surfaces exhibit high contact angles, which is characteristic of purely hydrophobic surfaces. However, little is known about the wetting behavior of droplets that nucleate and grow on hybrid surfaces during condensation. In fact, condensed droplets display a distinct wetting behavior during the droplet growth phase which cannot be reproduced by simply impinging droplets on hybrid surfaces. In this study, hybrid surfaces with three different spacing ratios were subjected to condensation tests using an environmental scanning electron microscopy (ESEM) and a condensation cell under ambient conditions. For hybrid surfaces with spacing ratio below 2, droplets were observed to form on top and sides of the micropillars, where they grew, coalesced with adjacent droplets, and shed after reaching a given size. After shedding, the top surface remained partially dry, which allowed for immediate droplet growth. For hybrid surfaces with spacing ratio equal to 2, a different wetting behavior was observed, where droplets basically coalesced and formed a thin liquid film which was ultimately driven into the valleys of the microstructure. The liquid shedding process led to the renucleation of droplets primarily on top of the dry hydrophilic sites. To better understand the nature of droplet wetting on hybrid surfaces, a surface energy-based model was developed to predict the transition between the two observed wetting behaviors at different spacing ratios. The experimental and analytical results indicate that micropillar spacing ratio is the key factor for promoting different wetting behavior of condensed droplets on hybrid surfaces.

  9. Overview of insoluble radioactive cesium particles emitted from the Fukushima Dai-ichi Nuclear Power Station

    Science.gov (United States)

    Satou, Yukihiko

    2017-04-01

    In the early stage of the Fukushima Dai-ichi Nuclear Power Station (F1NPS) accident, number of spot type contamination has been observed in computed autoradiography (Kashimura 2013, Shibata 2013, Satou 2014). It's means presence of radioactive particles, however, insoluble cesium particle was overlooked because cesium, which is dominant radioactive element in the accident, becomes ionized in the environment. Adachi et al. (2013) showed presence of cesium (Cs)-bearing particles within air dust sample collected at Tsukuba, 170 km south from the Fukushima site, in midnight of 14 to morning of 15 March 2011. These particles were micrometer order small particles and Cs was could be detectable as element using an energy dispersive X-ray spectroscopy (EDX). However, other radioactive elements such as Co-60, Ru-103 and uranium, which were dominant element of radioactive particles delivered from Chernobyl accident, could not detected. Abe et al. (2014) employed a synchrotron radiation (SR)-micro(μ)-X-ray analysis to the Cs-bearing particles, and they were concluded that (1) contained elements derived from nuclear fission processes and from nuclear reactor and fuel materials; (2) were amorphous; (3) were highly oxidized; and (4) consisted of glassy spherules formed from a molten mixture of nuclear fuel and reactor material. In addition, Satou et al. (2016) and Yamaguchi et al. (2016) disclosed that silicate is main component of Cs-bearing particles. Satou et al. (2015) discovered two types of radioactive particles from soil samples collected in the vicinity of the F1NPS. These particles were remained in the natural environment more than four years, silicate is main component in common of each group particles. Group A particles were very similar to Cs-bearing particles reported by Adachi et al. except particle shape. On the other hand, group B is big particles found in north area from the F1NPS, and the strongest particles contained 20 kBq of Cs-137 within a particle

  10. Synthesis of three-dimensional porous hyper-crosslinked polymers via thiol–yne reaction

    Directory of Open Access Journals (Sweden)

    Mathias Lang

    2016-11-01

    Full Text Available Herein we report the syntheses of two porous hyper-crosslinked polymers (HCPs via thiol–yne reaction with rigid tetrahedral and pseudo-octahedral core structures. Sorption measurements with nitrogen gas at 77 K revealed BET-surface areas up to 650 m²/g. Those networks also showed a high thermal stability as well as insolubility in common organic solvents.

  11. Solar water disinfection by singlet oxygen photogenerated with polymer-supported Ru(II) sensitizers

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Hernandez, M. Emilia; Manjon, Francisco; Garcia-Fresnadillo, David; Orellana, Guillermo [Laboratory of Applied Photochemistry, Department of Organic Chemistry, Faculty of Chemistry, Universidad Complutense de Madrid, 28040 Madrid (Spain)

    2006-10-15

    Using Escherichia coli and Enterococcus faecalis as model microorganisms, water disinfection has been demonstrated with singlet molecular oxygen (a reactive oxygen species) photogenerated by polymer-supported Ru(II) sensitizers and solar light. Both laboratory and sunlight tests were performed. The Ru(II) polypyridyl complex and its insoluble support have been optimized to provide maximum efficiency of singlet oxygen production and contact with the microorganism. (author)

  12. Hydrophobically Associating Polymers As Rheology Modifiers Polymères hydrophobiquement associatifs comme modificateurs de rhéologie

    Directory of Open Access Journals (Sweden)

    Aubry T.

    2006-12-01

    Full Text Available Hydrophobically associating water-soluble polymers are essentially hydrophilic polymer chains containing a small number of strongly hydrophobic groups, distributed or located at some priviledged sites on the chains. In aqueous media, hydrophobic units tend to associate in order to minimize their exposure to water, leading to reversible intra- and intermolecular hydrophobic junction networks, at even very low polymer concentrations. Such temporary networks influence strongly the linear and nonlinear rheological properties of the solutions and make such polymers candidates as rheology modifiers in aqueous-based formulations such as drilling fluids. In this paper, we present the main rheological characteristics of hydrophobically associating water-soluble polymers, the influence of the presence of a surfactant on their rheological properties and the rheology of solutions containing a mixture of associating and non-associating water-soluble polymers. Les polymères hydrophobiquement associatifs solubles dans l'eau sont essentiellement des chaînes de polymères hydrophiles contenant un petit nombre de groupements fortement hydrophobes répartis ou situés sur certains sites privilégiés des chaînes. En milieux aqueux, les unités hydrophobes tendent à s'associer de manière à réduire leur exposition à l'eau, conduisant à des réticulations de jonctions hydrophobes intra et intermoléculaires réversibles, même à de très faibles concentrations en polymères. De tels réseaux temporaires influencent fortement les propriétés rhéologiques linéaires et non linéaires des solutions et font de tels polymères des candidats comme modificateurs de rhéologie dans des formulations à base d'eau telles que les fluides de forage. Dans cet article, nous étudions les principales propriétés rhéologiques de polymères hydrophobiquement associatifs solubles dans l'eau, l'influence de la présence d'un agent tensio-actif sur leurs propriétés rh

  13. A Path to Soluble Molecularly Imprinted Polymers

    Science.gov (United States)

    Verma, Abhilasha; Murray, George M.

    2011-01-01

    Molecular imprinting is a technique for making a selective binding site for a specific chemical. The technique involves building a polymeric scaffold of molecular complements containing the target molecule. Subsequent removal of the target leaves a cavity with a structural “memory” of the target. Molecularly imprinted polymers (MIPs) can be employed as selective adsorbents of specific molecules or molecular functional groups. In addition, sensors for specific molecules can be made using optical transduction through lumiphores residing in the imprinted site. We have found that the use of metal ions as chromophores can improve selectivity due to selective complex formation. The combination of molecular imprinting and spectroscopic selectivity can result in sensors that are highly sensitive and nearly immune to interferences. A weakness of conventional MIPs with regard to processing is the insolubility of crosslinked polymers. Traditional MIPs are prepared either as monoliths and ground into powders or are prepared in situ on a support. This limits the applicability of MIPs by imposing tedious or difficult processes for their inclusion in devices. The size of the particles hinders diffusion and slows response. These weaknesses could be avoided if a means were found to prepare individual macromolecules with crosslinked binding sites with soluble linear polymeric arms. This process has been made possible by controlled free radical polymerization techniques that can form pseudo-living polymers. Modern techniques of controlled free radical polymerization allow the preparation of block copolymers with potentially crosslinkable substituents in specific locations. The inclusion of crosslinkable mers proximate to the binding complex in the core of a star polymer allows the formation of molecularly imprinted macromolecules that are soluble and processable. Due to the much shorter distance for diffusion, the polymers exhibit rapid responses. This paper reviews the methods

  14. 21 CFR 886.5928 - Soft (hydrophilic) contact lens care products.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Soft (hydrophilic) contact lens care products. 886.5928 Section 886.5928 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5928 Soft (hydrophilic) contact lens care products. (a)...

  15. Nano-biphasic ionic liquid systems composed of hydrophobic phosphonium salts and a hydrophilic ammonium salt.

    Science.gov (United States)

    Taguchi, Satomi; Ichikawa, Takahiro; Kato, Takashi; Ohno, Hiroyuki

    2012-05-28

    A combination of a phosphonium-type-zwitterions-lithium bis(trifluoromethanesulfonyl)imide complex and a hydrophilic ammonium salt provides a nanosegregated liquid-crystalline matrix consisting of hydrophilic ionic liquid (IL) domains and hydrophobic IL domains. This journal is © The Royal Society of Chemistry 2012

  16. Soft/hard Coupled Amphiphilic Polymer Nanospheres for Water Lubrication.

    Science.gov (United States)

    Li, Zhaoxia; Ma, Shuanhong; Zhang, Ga; Wang, Daoai; Zhou, Feng

    2018-02-22

    Amphiphilic polymer nanospheres of poly (3-Sulfopropyl methacrylate potassium salt -co-styrene) [P(SPMA-co-St)] were prepared by a simple soap-free emulsion polymerization method and used as efficient water lubrication additive to enhance the anti-wear behaviors of Ti6Al4V alloy. The monodisperse and flexible P(SPMA-co-St) bi-component copolymer nanospheres were synthesized with a controllable manner by adjusting the mass fraction ratio of the monomers, with the hydrophobic polystyrene (PSt) as the hard and skeletal carrier component, and the hydrophilic PSPMA with hydration layer structure as the soft lubrication layer in the course of friction. The influences of the monomers concentration, the copolymer nanospheres additive content, the load and the frequency of the friction conditions on their tribological properties were studied in detail, and a probable anti-wear mechanism of the soft/hard coupled copolymer nanospheres under water lubrication was also proposed. The results show that compared with pure PSt the P(SPMA-co-St) polymer nanospheres exhibited better anti-wear property as additive for water lubrication, and the friction coefficient and the wear volume were first decrease and then increase with the increase of the SPMA content, indicating the hydrophilic SPMA has a significant effect on lubrication properties owing to its hydration performance. Furthermore, with the increase of polymer nanospheres concentration, the friction coefficient and wear amount also decreased to a stable and low value at the saturation concentration of 1 w%. The flexible polymer nanospheres with hydrophilic and soft SPMA shell and rigid PS core exhibited good friction-reduction and anti-wear performance as lubrication additive, indicating promising and potential applications in water lubrication and biological lubrication.

  17. Evaluation of a silicon oxynitride hydrophilic interaction liquid chromatography column in saccharide and glycoside separations.

    Science.gov (United States)

    Wan, Huihui; Sheng, Qianying; Zhong, Hongmin; Guo, Xiujie; Fu, Qing; Liu, Yanfang; Xue, Xingya; Liang, Xinmiao

    2015-05-01

    The retention characteristics of a silicon oxynitride stationary phase for carbohydrate separation were studied in hydrophilic interaction chromatography mode. Four saccharides including mono-, di-, and trisaccharides were employed to investigate the effects of water content and buffer concentration in the mobile phase on hydrophilic interaction liquid chromatography retention. For the tested saccharides, the silicon oxynitride column demonstrated excellent performance in terms of separation efficiency, hydrophilicity, and interesting separation selectivity for carbohydrates compared to the bare silica stationary phase. Finally, the silicon oxynitride hydrophilic interaction liquid chromatography column was employed in the separation of complex samples of fructooligosaccharides, saponins, and steviol glycoside from natural products. The resulting chromatograms demonstrated good separation efficiency and longer retention compared with silica, which further confirmed the advantages and potential application of silicon oxynitride stationary phase for hydrophilic interaction liquid chromatography separation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Total, insoluble and soluble dietary fiber contents of selected Kuwaiti composite dishes.

    Science.gov (United States)

    Al-Amiri, H A; Al-Hamad, N M; Al-Awadhi, F A; Al-Foudari, M Y; Al-Otaibi, J A; Binheji, A H

    2011-03-01

    Total dietary fiber (TDF), insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) contents of 37 composite dishes commonly consumed in the State of Kuwait were determined by the AOAC enzymatic-gravimetric method of Prosky et al. Levels (g/100 g) of SDF ranged over 0.3-0.5 in fish-based dishes, 0.3-2.6 in meat-based dishes, 0.1-1.4 in rice dishes, 3.2-4.6 in vegetable dishes, 0.3-0.7 in soup dishes, 0 in dairy dishes, 0.7-0.8 in sandwiches, and 0.1-5.0 in sweet dishes. IDF levels ranged over 1.1-1.8 in fish-based, 0.9-3.2 in meat-based, 0.6-2.7 in rice, 2.1-4.0 in vegetables, 0.6-3.4 in soup, 0 in dairy, 0.2-0.3 in sandwiches, and 0.2-11.6 in sweets. TDF values ranged over 1.4-2.3 in fish-based, 1.2-3.7 in meat-based, 0.3-4.1 in rice, 3.2-4.6 in vegetables, 0.9-3.8 in soup, 0 in dairy, 0.7-0.8 in sandwiches and 0.3-15.4 in sweets. This work attempts to provide new data on TDF, IDF and SDF of selected commonly consumed Kuwaiti composite dishes.

  19. Source attribution of insoluble light-absorbing particles in seasonal snow across northern China

    Directory of Open Access Journals (Sweden)

    R. Zhang

    2013-06-01

    Full Text Available Seasonal snow samples obtained at 46 sites in 6 provinces of China in January and February 2010 were analyzed for a suite of chemical species and these data are combined with previously determined concentrations of insoluble light-absorbing particles (ILAP, including all particles that absorb light in the 650–700 nm wavelength interval. The ILAP, together with 14 other analytes, are used as input to a positive matrix factorization (PMF receptor model to explore the sources of ILAP in the snow. The PMF analysis for ILAP sources is augmented with backward trajectory cluster analysis and the geographic locations of major source areas for the three source types. The two analyses are consistent and indicate that three factors/sources were responsible for the measured light absorption of snow: a soil dust source, an industrial pollution source, and a biomass and / or biofuel burning source. Soil dust was the main source of the ILAP, accounting for ~53% of ILAP on average.

  20. Improving the controlled release of water-insoluble emodin from amino-functionalized mesoporous silica

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yunqiang; Wang Chunfeng [Shandong Provincial Key Laboratory of Fine Chemicals, School of Chemistry, Shandong Polytechnic University, Jinan 250353, Shandong (China); Zhou Guowei, E-mail: guoweizhou@hotmail.com [Shandong Provincial Key Laboratory of Fine Chemicals, School of Chemistry, Shandong Polytechnic University, Jinan 250353, Shandong (China); Wu Yue; Chen Jing [Shandong Provincial Key Laboratory of Fine Chemicals, School of Chemistry, Shandong Polytechnic University, Jinan 250353, Shandong (China)

    2012-06-15

    Several types of amino-functionalized mesoporous silica, including F5-SBA-15, F10-SBA-15, and F15-SBA-15 were prepared through co-condensation of tetraethoxysilane (TEOS) and (3-aminopropyl)triethoxysilane (APTES) in varying molar ratios (5 mol%, 10 mol%, and 15 mol%) via a hydrothermal process. The materials obtained were characterized by means of small-angle X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, N{sub 2} adsorption-desorption, Fourier transformed infrared spectra, and X-ray photoelectron spectroscopy. Increasing APTES molar ratios decreased the degree of orderliness of the functionalized mesoporous silica. Pure and amino-functionalized SBA-15 samples were employed as supports for the controlled release of water-insoluble drug emodin. Loading experiments showed that drug loading capacities mainly depended on the surface areas and pore diameters of the carriers. Controlled release profiles of emodin-loaded samples were studied in phosphate buffered saline (PBS, pH 7.4), and results indicated that the emodin release rate could be controlled by surface amino-functionalized carriers. Emodin loaded on functionalized mesoporous supports exhibited a lower release rate than that of loaded on pure SBA-15, emodin loaded on F10-SBA-15 showed the smallest release amount (71.74 wt%) after stirring in PBS for 60 h. Findings suggest that functionalized mesoporous SBA-15 is a promising carrier for achieving prolonged release time periods.

  1. Water-Insoluble Photosensitizer Nanocolloids Stabilized by Supramolecular Interfacial Assembly towards Photodynamic Therapy

    Science.gov (United States)

    Liu, Yamei; Ma, Kai; Jiao, Tifeng; Xing, Ruirui; Shen, Guizhi; Yan, Xuehai

    2017-02-01

    Nanoengineering of hydrophobic photosensitizers (PSs) is a promising approach for improved tumor delivery and enhanced photodynamic therapy (PDT) efficiency. A variety of delivery carriers have been developed for tumor delivery of PSs through the enhanced permeation and retention (EPR) effect. However, a high-performance PS delivery system with minimum use of carrier materials with excellent biocompatibility is highly appreciated. In this work, we utilized the spatiotemporal interfacial adhesion and assembly of supramolecular coordination to achieve the nanoengineering of water-insoluble photosensitizer Chlorin e6 (Ce6). The hydrophobic Ce6 nanoparticles are well stabilized in a aqueous medium by the interfacially-assembled film due to the coordination polymerization of tannic acid (TA) and ferric iron (Fe(III)). The resulting Ce6@TA-Fe(III) complex nanoparticles (referenced as Ce6@TA-Fe(III) NPs) significantly improves the drug loading content (~65%) and have an average size of 60 nm. The Ce6@TA-Fe(III) NPs are almost non-emissive as the aggregated states, but they can light up after intracellular internalization, which thus realizes low dark toxicity and excellent phototoxicity under laser irradiation. The Ce6@TA-Fe(III) NPs prolong blood circulation, promote tumor-selective accumulation of PSs, and enhanced antitumor efficacy in comparison to the free-carrier Ce6 in vivo evaluation.

  2. Hitchhiking vesicular transport routes to the vacuole: Amyloid recruitment to the Insoluble Protein Deposit (IPOD).

    Science.gov (United States)

    Kumar, Rajesh; Neuser, Nicole; Tyedmers, Jens

    2017-03-04

    Sequestration of aggregates into specialized deposition sites occurs in many species across all kingdoms of life ranging from bacteria to mammals and is commonly believed to have a cytoprotective function. Yeast cells possess at least 3 different spatially separated deposition sites, one of which is termed "Insoluble Protein Deposit (IPOD)" and harbors amyloid aggregates. We have recently discovered that recruitment of amyloid aggregates to the IPOD uses an actin cable based recruitment machinery that also involves vesicular transport. 1 Here we discuss how different proteins known to be involved in vesicular transport processes to the vacuole might act to guide amyloid aggregates to the IPOD. These factors include the Myosin V motor protein Myo2 involved in transporting vacuolar vesicles along actin cables, the transmembrane protein Atg9 involved in the recruitment of large precursor hydrolase complexes to the vacuole, the phosphatidylinositol/ phosphatidylcholine (PI/PC) transfer protein Sec 14 and the SNARE chaperone Sec 18. Furthermore, we present new data suggesting that the yeast dynamin homolog Vps1 is also crucial for faithful delivery of the amyloid model protein PrD-GFP to the IPOD. This is in agreement with a previously identified role for Vps1 in recruitment of heat-denatured aggregates to a perivacuolar deposition site. 2.

  3. Coalescence of droplets laden with insoluble surfactant on a preset liquid film.

    Science.gov (United States)

    Li, Chunxi; Lin, Yuxi; Zhang, Ran; Ye, Xuemin

    2018-01-31

    A model for the evolution of two droplets laden with insoluble surfactant coalescing on a preset film is established according to the lubrication theory, and the coalescence processes are simulated. The role of the surfactant and its inherent mechanism are investigated, the effects of the Marangoni number, the preset liquid film thickness and the initial spacing between the two droplets on the coalescence are examined. The results show that the droplets encounter each other, gradually overlap, and finally coalesce into a "new" droplet. The Marangoni effect is beneficial to the convergence of the two inner leading fronts of the droplets in the early stage, but it hinders the accumulation of the droplets and subsequent coalescence. Increasing the Marangoni number promotes not only the aforementioned inhibition, but also the convergence of the two leading fronts towards the center, which speeds up the coalescence of the surfactant. Moreover, the diffusion of the surfactant towards the outsides of the droplets is accelerated; hence, its distribution along the droplet surface is more uniform after the coalescence. The droplets and the surfactant undertake a longer "journey" to achieve coalescence when their initial spacing is increased; increasing the preset film thickness shortens the time of coalescence required.

  4. Novel surface-active ionic liquids used as solubilizers for water-insoluble pesticides.

    Science.gov (United States)

    Fan, Tengfei; Chen, Chong; Fan, Tingting; Liu, Fengmao; Peng, Qingrong

    2015-10-30

    Three surface active ionic liquids (ILs) containing organic anions but no halides were used as solubilizers for water insoluble pesticides and as well as alternates for similar ILs with halide anions, which have been increasingly popular in the agricultural practice. The solubilities of five pesticides (fluazifop-P, clethodim, pyrethrin, fosthiazate, and prochloraz) in three aqueous micellar systems, each containing 1-octyl-3-methylimidazolium--tartrate ([OMIM][Tart]), 1-octyl-3-methylimidazolium-l-proline ([OMIM][Prol]), 1-octyl-3-methylimidazolium-l-lactate ([OMIM][lact]), respectively, were measured. The solubilities of all five pesticides were found to increase with the increasing concentrations of ILs solubilzers The enhancements in solubilities were related to surface activities of these SAILs, as indicated in the results of the measurements of their corresponding critical aggregation concentration (CAC), lowest surface tension (γcac), maximum surface excess concentration (Γmax) and minimum area per molecule (Amin) of aqueous solutions of ILs. When comparing with similar ILs with halides as counter anions, we found that these ILs with organic counterions are at least comparable, often more effective solubilizers for all of the five very different pesticides we tested. We conclude that these novel SAILs with organic counterions would serve as at least similarly effective and more environmentally-friendly solubilizers over the more traditional ones with halides. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Rheological and structural characterization of agar/whey proteins insoluble complexes.

    Science.gov (United States)

    Rocha, Cristina M R; Souza, Hiléia K S; Magalhães, Natália F; Andrade, Cristina T; Gonçalves, Maria Pilar

    2014-09-22

    Complex coacervation between whey proteins and carboxylated or highly sulphated polysaccharides has been widely studied. The aim of this work was to characterise a slightly sulphated polysaccharide (agar) and whey protein insoluble complexes in terms of yield, composition and physicochemical properties as well as to study their rheological behaviour for better understanding their structure. Unlike other sulphated polysaccharides, complexation of agar and whey protein at pH 3 in the absence of a buffering agent resulted in a coacervate that was a gel at 20°C with rheological properties and structure similar to those of simple agar gels, reinforced by proteins electrostatically aggregated to the agar network. The behaviour towards heat treatment was similar to that of agar alone, with a high thermal hysteresis and almost full reversibility. In the presence of citrate buffer, the result was a "flocculated solid", with low water content (75-81%), whose properties were governed by protein behaviour. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. NMR characterization of lignins isolated from fruit and vegetable insoluble dietary fiber.

    Science.gov (United States)

    Bunzel, Mirko; Ralph, John

    2006-10-18

    Compositional information for lignins in food is rare and concentrated on cereal grains and brans. As lignins are suspected to have important health roles in the dietary fiber complex, the confusing current information derived from nonspecific lignin determination methods needs to be augmented by diagnostic structural studies. For this study, lignin fractions were isolated from kiwi, pear, rhubarb, and, for comparison, wheat bran insoluble dietary fiber. Clean pear and kiwi lignin isolates allowed for substantive structural profiling, but it is suggested that the significance of lignin in wheat has been overestimated by reliance on nonspecific analytical methods. Volume integration of NMR contours in two-dimensional (13)C-(1)H correlation spectra shows that pear and wheat lignins have comparable guaiacyl and syringyl contributions and that kiwi lignins are particularly guaiacyl-rich (approximately 94% guaiacyl) and suggest that rhubarb lignins, which could not be isolated from contaminating materials, are as syringyl-rich (approximately 96% syringyl) as lignins from any known natural or transgenic fiber source. Typical lignin structures, including those newly NMR-validated (glycerols, spirodienones, and dibenzodioxocins), and resinols implicated as possible mammalian lignan precursors in the gut are demonstrated via their NMR correlation spectra in the fruit and vegetable samples. A novel putative benzodioxane structure appears to be associated with the kiwi lignin. It is concluded that the fruits and vegetables examined contain authentic lignins and that the detailed structural analysis exposes limitations of currently accepted analytical methods.

  7. Tunable Optical Polymer Systems

    National Research Council Canada - National Science Library

    Jenekhe, S. A; Bard, Allen J; Chen, S. H; Hammond, P. T; Rothberg, L. J

    2004-01-01

    .... The synthesis and properties of new electrochromic polymers are described. Electrochromic devices incorporating conjugated polymers have been fabricated and found to be durable past 100,000 cycles...

  8. Fully biodegradable self-rolled polymer tubes: a candidate for tissue engineering scaffolds.

    Science.gov (United States)

    Zakharchenko, Svetlana; Sperling, Evgeni; Ionov, Leonid

    2011-06-13

    We report an approach for the fabrication of fully biodegradable self-rolled tubes based on patterned polysuccinimide/polycaprolactone bilayers. These polymers are biocompatible, biodegradable, produced industrially, and are already approved for biomedical purposes. Both polycaprolactone and polysuccinimide are hydrophobic and intrinsically water-insoluble. Polysuccinimide, however, hydrolyzes in physiological buffer environment yielding water-swellable polyaspartic acid that causes the rolling of the polymer bilayer and formation of tubes. We demonstrate the possibility to encapsulate yeast cells using self-rolled tubes.

  9. Synthesis of Donor-Acceptor Conjugated Polymers by "CLICK" Polymerization for OPV applications

    DEFF Research Database (Denmark)

    Brandt, Rasmus Guldbæk; Yu, Donghong

    The intent of this study was to utilize the Copper(I)-catalyzed Azide Alkyne Cycloaddition (CuAAC) as a polymerization technique (“Click” Polymerization) for synthesizing novel π-conjugated low band gap polymers for organic photovoltaic applications (OPV). The chosen approach was to synthesize...... an alternating electron donating (donor, D) and electron withdrawing (acceptor, A) co-polymer. The chosen monomers were well known units, and the novelty lies in using the monomer units with the click methodology. An insoluble alternating copolymer consisting of 2,7-diazido-9,9-dioctyl-9Hflourene and 1...

  10. Polymer Directed Self-Assembly of pH-Responsive Antioxidant Nanoparticles

    OpenAIRE

    Tang, Christina; Amin, Devang; Messersmith, Phillip B.; Anthony, John E.; Prud’homme, Robert K.

    2015-01-01

    We have developed pH-responsive, multifunctional nanoparticles based on encapsulation of an antioxidant, tannic acid (TA), using Flash NanoPrecipitation, a polymer directed self-assembly method. Formation of insoluble coordination complexes of tannic acid and iron during mixing drives nanoparticle assembly. Tuning the core material to polymer ratio, the size of the nanoparticles can be readily tuned between 50 and 265 nm. The resulting nanoparticle is pH-responsive, i.e. stable at pH 7.4 and ...

  11. From Commodity Polymers to Functional Polymers

    OpenAIRE

    Tao Xiang,; Ling-Ren Wang; Lang Ma; Zhi-Yuan Han; Rui Wang; Chong Cheng; Yi Xia; Hui Qin; Chang-Sheng Zhao

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outs...

  12. Develop Hydrophilic Conductive Coating Technology with High Oxidation Resistance for Non-Flow-Through PEM Fuel Cells and Electrolyzers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ElectroChem proposes to develop oxidation resistant, electrically conductive, hydrophilic coatings in PEM fuel cells and in PEM electrolyzers. The use of hydrophilic...

  13. A Self-Switchable Polymer Reactor for Controlled Catalytic Chemistry Processes with a Hyperbranched Structure

    Directory of Open Access Journals (Sweden)

    Rong Luo

    2018-02-01

    Full Text Available A self-switchable polymer reactor with a hyperbranched structure for controlled catalytic chemistry processes is reported. This polymer reactor was made of silver nanoparticles and a polymer carrier consisting of hyperbranched polyethylenimine and hydroxyethyl acrylate that behaved as thermally switchable domains. Below the transfer temperature, relatively strong catalytic reactivity was demonstrated due to the leading role of hydrophilic groups in the switchable domains, which opened access to the substrate for the packaged silver nanoparticles. In contrast, it showed weak catalysis at relatively high temperatures, reducing from the significantly increased hydrophobicity in the switchable domains. In this way, the polymer reactor displays controllable, tunable, catalytic activity based on this approach. This novel design opens up the opportunity to develop intelligent polymer reactors for controlled catalytic processes.

  14. Vacuna fenol-insoluble contra la brucelosis humana: evaluacion del poder inmunogenico en cobayos Phenol insoluble extract vaccine for the prevention of brucellosis in humans: evaluation in guinea pigs

    Directory of Open Access Journals (Sweden)

    J. Bolpe

    1991-02-01

    Full Text Available Se examinó una vacuna diseñada para inmunizar al hombre, preparada con extracto de fenol insoluble, para determinar si protegía a cobayos contra el desafío con la cepa virulenta B. abortus 2308. Se incluyeron en el experimento las vacunas vivas atenuadas B. abortus cepa 19 y B. melitensis Rev. 1, para comparar los resultados. Se vacunaron 93 animales en cada grupo, que fueron subdivididos en subgrupos de 31 y se los desafió con 10(4, 10³ y 10² unidades formadoras de colonias de la cepa B. abortus 2308 virulenta. El análisis global de los resultados demostró una protección del 11.9% en animales vacunados con el extracto de fenol insoluble, 65% en los vacunados con B. abortus cepa 19 y 95% en el grupo que recibió vacuna B. melitensis Rev. 1.A phenol insoluble extract vaccine proposed to immunize men against brucellosis was tested for its ability in protecting guinea pigs against challenge with virulent Brucella abortus strain 2308. Living attenuated Brucella abortus strain 19 and B. melitensis Rev. 1 were included in the experiment for comparison. Ninety three animals were vaccinated in each group and subdivided in subgroups of 31 for challenge with 10(4,10³ and 10² colony forming units of virulent B. abortus 2308. A global analysis of the results showed protection of 11.9%, 65% and 95% in animals vaccinated with phenol insoluble extract, strain 19 and Rev. 1, respectively.

  15. Effect of insoluble calcium concentration on endogenous syneresis rate in rennet-coagulated bovine milk.

    Science.gov (United States)

    Choi, J; Horne, D S; Lucey, J A

    2015-09-01

    0.96) with the loss tangent values of gels (indicating greater mobility), probably due to the loss of insoluble calcium phosphate crosslinking within micelles, which was significantly negatively correlated (r≥0.81) with the rate constant for endogenous syneresis. In the EDTA trial, with an increase in the EDTA concentration no maximum was observed in the rate constants related to proteolysis of κ-casein hairs or crosslinking of these activated sites. The rate constant for endogenous syneresis decreased at higher EDTA levels. The different rheological/modeling behavior in the EDTA trials was likely due to the very significant inhibition of rennet gelation induced by the use of EDTA, which also resulted in extremely long reaction times. Our modified Carlson model fit our experimental pH trial data very well, which indicates that the rennet gel system has the potential to synerese from the start; indeed this ability is an innate property of the casein micelle. Endogenous syneresis was enhanced by the loss of insoluble calcium phosphate crosslinking within casein micelles as this increased bond mobility within rennet gels. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Enhanced catalytic activity and inhibited biofouling of cathode in microbial fuel cells through controlling hydrophilic property

    Science.gov (United States)

    Li, Da; Liu, Jia; Wang, Haiman; Qu, Youpeng; Zhang, Jie; Feng, Yujie

    2016-11-01

    The hydrophilicity of activated carbon cathode directly determines the distribution of three-phase interfaces where oxygen reduction occurs. In this study, activated carbon cathodes are fabricated by using hydrophobic polytetrafluoroethylene (PTFE) and amphiphilic LA132 at various weight ratio to investigate the effect of hydrophilic property on cathode performance. Contact angle tests confirm the positive impact of LA132 content on hydrophilicity. Cathode with 67 wt% LA132 content shows the highest electrochemical activity as exchange current density increases by 71% and charge transfer resistance declines by 44.6% compared to that of PTFE cathode, probably due to the extended reaction interfaces by optimal hydrophilicity of cathode so that oxygen reduction is facilitated. As a result, the highest power density of 1171 ± 71 mW m-2 is obtained which is 14% higher than PTFE cathode. In addition to the hydrophilicity, this cathode had more negative charged surface of catalyst layer, therefore the protein content of cathodic biofilm decreased by 47.5%, indicating the effective bacterial inhibition when 67 wt% LA132 is used. This study shows that the catalytic activity of cathode is improved by controlling proper hydrophilicity of cathode, and that biofilm can be reduced by increasing hydrophilicity and lowering the surface potential.

  17. Effect of low doses of 14 MeV neutrons on polymers.

    Science.gov (United States)

    Rivaton, Agnès; Arnold, Jack; Dos Santos, Morgane; Bussière, Pierre-Olivier; Taviot-Gueho, Christine

    2010-11-01

    The structural modifications of polymers irradiated with 14 MeV neutrons were studied. Two elastomers, a polypropylene-type polymer and poly(ethylene oxide) were exposed to low doses of fast neutrons in the range of 0.3-14 Gy. The radiation damages were observed at the molecular scale by infrared spectroscopy. The morphological changes were investigated by steric exclusion chromatography, insoluble fraction measurements, differential scanning calorimetry and X-ray diffraction. It was found that neutrons provoked oxidation processes accompanied by modifications in the polymer architecture, including chain scissions, crosslinking reactions and changes in the crystallinity. Moreover, the conventional antioxidants were shown to be inefficient in inhibiting the aging of the polymers. These results also suggest that the radiation damages could be used successfully for dosimetry applications using an easily implementable protocol.

  18. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    Science.gov (United States)

    Zhai, Peng; Chen, X B; Schreyer, David J

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Retention Behavior of Inorganic Anions in Hydrophilic Interaction Chromatography.

    Science.gov (United States)

    Takayama, Nobuyuki; Lim, Lee Wah; Takeuchi, Toyohide

    2017-01-01

    The retention behavior of inorganic anions was studied in hydrophilic interaction chromatography (HILIC). In this study, five kinds of HILIC stationary phases (amino, imidazole, amide, pyridine and zwitterionic) were investigated. It was found that only amino and imidazole columns exhibited the separation of inorganic anions under HILIC conditions. The retention mechanism was further investigated under both columns. A reversed elution order of inorganic anions was observed under the HILIC condition compared with those observed under the ion-exchange chromatography mode (IEC). The effect of salt species and their concentration in the eluent were investigated under constant acetonitrile (ACN) content. Sodium chloride and sodium perchlorate were chosen as the salt, and the salt (sodium perchlorate) concentration was varied from 10 to 40 mM to confirm the effect of the electrostatic interaction. The slope values of the plots of the log retention factor (k) versus the log eluent concentration were calculated to be between -0.43 and -0.45 for the amino column, while those obtained on the imidazole column were between -0.68 and -0.73. Various concentrations of ACN were also examined with 20 mM sodium perchlorate, and the typical HILIC retention behavior was observed on both amino and imidazole columns. Due to the obtained results, it is considered that the separation of inorganic anions under the HILIC condition was achieved by both electrostatic interaction and partition.

  20. Superstable Ultrathin Water Film Confined in a Hydrophilized Carbon Nanotube.

    Science.gov (United States)

    Tomo, Yoko; Askounis, Alexandros; Ikuta, Tatsuya; Takata, Yasuyuki; Sefiane, Khellil; Takahashi, Koji

    2018-02-13

    Fluids confined in a nanoscale space behave differently than in the bulk due to strong interactions between fluid molecules and solid atoms. Here, we observed water confined inside "open" hydrophilized carbon nanotubes (CNT), with diameter of tens of nanometers, using transmission electron microscopy (TEM). A 1-7 nm water film adhering to most of the inner wall surface was observed and remained stable in the high vacuum (order of 10 -5 Pa) of the TEM. The superstability of this film was attributed to a combination of curvature, nanoroughness, and confinement resulting in a lower vapor pressure for water and hence inhibiting its vaporization. Occasional, suspended ultrathin water film with thickness of 3-20 nm were found and remained stable inside the CNT. This film thickness is 1 order of magnitude smaller than the critical film thickness (about 40 nm) reported by the Derjaguin-Landau-Verwey-Overbeek theory and previous experimental investigations. The stability of the suspended ultrathin water film is attributed to the additional molecular interactions due to the extended water meniscus, which balances the rest of the disjoining pressures.

  1. Thin shell vesicles composed of hydrophilic plate-like nanoparticles

    Science.gov (United States)

    Subramaniam, Anand; Wan, Jiandi; Gopinath, Arvind; Stone, Howard

    2011-03-01

    Nanopowders of graphene oxide, montmorillonite and laponite spontaneously delaminate into ultrathin nanoscopic plates when dispersed in water. These plates, which are typically ~ 1 nm thick and microns in lateral dimension, have found many uses as precursors to graphene, ceramics, layer-by-layer structures, and as structural modifiers of nanocomposites. Here we show that mechanical forces due to shear in a narrow gap can assemble hydrophilic plate-like particles on air bubbles, forming stable nanoplated armored bubbles. Translucent inorganic vesicles (vesicles defined here as closed thin-shelled structures with the same liquid inside and outside) of these particles are produced when the nanoplated armored bubbles are exposed to common water-miscible organic liquids and surfactants. These inorganic vesicles are mechanically robust, have walls that are about six nanometres thick, and are perforated with pores of submicron dimensions. We characterize the phenomenon and find that a wetting transition at the scale of the nanoparticles is the primary mechanism of formation. The discovery of these novel inorganic structures raises a wealth of questions of fundamental interest in materials and surface science.

  2. Some considerations about the hydrophilic-lipophilic balance system.

    Science.gov (United States)

    Pasquali, Ricardo C; Taurozzi, Melina P; Bregni, Carlos

    2008-05-22

    The methods and results obtained by Griffin et al. in the determination of the hydrophilic-lipophilic balance (HLB) values of non-ionic surfactants and of required HLB values of oil mixtures are reviewed in the present work. HLB values published by Griffin were compared with those obtained by calculations from theoretic chemical formulas. Griffin HLB values of polyoxyethylene alkyl ethers, polyoxyethylene monoesters and propylene glycol monoesters coincide with those obtained from such theoretical chemical formulations. These results demonstrate that, for these surfactants, Griffin did not experimentally obtain their HLB values, but instead calculated them from theoretic formulae. For the calculation of the HLB values of glycerol monostearate, sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters, Griffin's assumptions were possibly based upon the mean saponification values of the ester and the acid of the fatty acid. It is concluded that the HLB values of non-ionic surfactants were not rigorously defined. Moreover, Griffin could not demonstrate the validity of the assumption that individual required HLB values can be added up to obtain the overall required HLB value of an oil mixture. The HLB and required HLB values published by Griffin should only be taken as approximate guidelines.

  3. PLGA/alginate composite microspheres for hydrophilic protein delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Peng [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Chen, X.B. [Department of Mechanical Engineering, University of Saskatchewan, S7N5A9 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Schreyer, David J., E-mail: david.schreyer@usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada)

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility.

  4. Shear bond strength of hydrophilic adhesive systems to enamel.

    Science.gov (United States)

    Hara, A T; Amaral, C M; Pimenta, L A; Sinhoreti, M A

    1999-08-01

    To compare the enamel shear bond strength of four hydrophilic adhesive systems: one multiple-bottle (Scotchbond Multi-Purpose Plus), two one-bottle (Stae, Single Bond) and one self-etching (Etch & Prime). 120 bovine incisor teeth were obtained, embedded in polyester resin, polished to 600 grit to form standardized enamel surfaces, and randomly assigned to four groups (n = 30). Each adhesive system was used on enamel according to the manufacturer's instructions, and resin-based composite (Z100) cylinders with 3 mm diameter and 5 mm height were bonded. Specimens were stored in humid environment for 1 week, and bond strength was determined using a universal testing machine, at a crosshead speed of 0.5 mm/minute. The mean shear bond strength values (MPa +/- SD) were: Single Bond: 24.28 +/- 5.27 (a); Scotchbond Multi-Purpose Plus: 21.18 +/- 4.35 (ab); Stae: 19.56 +/- 4.71 (b); Etch & Prime 3.0: 15.13 +/- 4.92 (c). ANOVA revealed significant difference in means (P bottle systems.

  5. Hydrophilic actinide complexation studied by solvent extraction radiotracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Rydberg, J. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Chemistry and Radiochemistry Consultant Group, Vaestra Froelunda (Sweden)

    1996-10-01

    Actinide migration in the ground water is enhanced by the formation of water soluble complexes. It is essential to the risk analysis of a wet repository to know the concentration of central atoms and the ligands in the ground water, and the stability of complexes formed between them. Because the chemical behavior at trace concentrations often differ from that at macro concentrations, it is important to know the chemical behavior of actinides at trace concentrations in ground water. One method used for such investigations is the solvent extraction radiotracer (SXRT) technique. This report describes the SXRT technique in some detail. A particular reason for this analysis is the claim that complex formation constants obtained by SXRT are less reliable than results obtained by other techniques. It is true that several difficulties are encountered in the application of SXRT technique to actinide solution, such as redox instability, hydrophilic complexation by side reactions and sorption, but it is also shown that a careful application of the SXRT technique yields results as reliable as by any other technique. The report contains a literature survey on solvent extraction studies of actinide complexes formed in aqueous solutions, particularly by using the organic reagent thenoyltrifluoroacetone (TTA) dissolved in benzene or chloroform. Hydrolysis constants obtained by solvent extraction are listed as well as all actinide complexes studied by SX with inorganic and organic ligands. 116 refs, 11 tabs.

  6. RANDOMIZED CLINICAL TRIAL: SOLUBLE/INSOLUBLE FIBER OR PSYLLIUM FOR CHRONIC CONSTIPATION

    Science.gov (United States)

    Erdogan, Askin; Rao, Satish; Thiruvaiyaru, Dharma; Lee, Yeong Yeh; Adame, Enrique Coss; Valestin, Jessica; O’Banion, Meagan

    2016-01-01

    SUMMARY Background Fiber supplements are useful, but whether a plum-derived mixed fiber that contains both soluble and insoluble fiber improves constipation is unknown. Aim We investigated the efficacy and tolerability of mixed fiber versus psyllium in a randomized double blind controlled trial. Methods Constipated patients (Rome III) received mixed fiber or psyllium, 5g bid, for 4 weeks. Daily symptoms and stool habit were assessed using stool diary. Subjects with ≥1 complete spontaneous bowel movement (CSBM)/week above baseline for ≥ 2/4 weeks were considered responders. Secondary outcome measures included stool consistency, bowel satisfaction, straining, gas, bloating, taste, dissolvability and Quality of Life (QOL). Results 72 subjects (MF=40; psyllium=32) were enrolled and 2 from psyllium group withdrew. The mean CSBM/week increased with both mixed fiber (ppsyllium (p=0.0002) without group difference. There were 30 (75%) responders with mixed fiber and 24 (75%) with psyllium (p=0.9). Stool consistency increased (p=0.04), straining (p=0.006), and bloating scores decreased (p=0.02) without group differences. Significantly more patients reported improvement in flatulence (53% vs. 25%, p=0.01) and felt that mixed fiber dissolved better (p=0.02) compared to psyllium. QOL improved (p=0.0125) with both treatments without group differences. Conclusions Mixed fiber and psyllium were equally efficacious in improving constipation and QOL. Mixed fiber was more effective in relieving flatulence, bloating and dissolved better. Mixed fiber is effective and well tolerated. Clinical Trial No: NCT01288508 PMID:27125883

  7. Physicochemical and Functional Properties of Insoluble Dietary Fiber Isolated from Bambara Groundnut (Vigna subterranea [L.] Verdc.).

    Science.gov (United States)

    Diedericks, Claudine F; Jideani, Victoria A

    2015-09-01

    Bambara groundnut (BGN) is a widely cultivated legume with a rich nutritional profile, yet despite its many benefits it still remains underutilized. To highlight its potential value, 4 BGN varieties-brown, red, black eye, and brown eye were subjected to sequential enzymatic treatments followed by centrifugation to obtain the insoluble dietary fiber (IDF) fraction. The IDFs were vacuum-dried and evaluated for color, hydration properties, fat absorption, polyphenolic compounds, neutral sugars, and uronic acids. An optimized white bread formulation was also determined using brown BGN-IDF in an optimal (IV) mixture design. Three mixture components constrained at lower and upper limits (water: 57% to 60%, yeast: 2.3% to 5.3%, and BGN-IDF: 7% to 10%) were evaluated for their effects on responses of specific loaf volume, gumminess, chewiness, and resilience of the loaves. All BGN-IDFs differed significantly (P ≤ 0.05) across all color parameters. Polyphenols were significantly (P ≤ 0.05) highest in red and brown BGN-IDFs. Arabinose/galactose (31.04% to 37.12%), xylose (16.53% to 27.30%), and mannose (14.48% to 22.24%) were the major sugars identified. Swelling capacity was significantly (P ≤ 0.05) highest for brown eye BGN-IDF (7.72 ± 0.49 mL/g). Water retention capacity ranged from 1.63 to 2.01 g water/g dry weight. Fat absorption for red BGN-IDF differed significantly (P ≤ 0.05). Furthermore, the best optimal white bread formulation enriched with brown BGN-IDF was established with numerical optimization at 59.5% water, 4.3% yeast, and 8.5% BGN-IDF. Overall positive physicochemical and functional properties were observed for BGN-IDFs, and it was shown that an optimal white bread enriched with BGN-IDF could be produced. © 2015 Institute of Food Technologists®

  8. Purification and biochemical characterization of insoluble acid invertase (INAC-INV) from pea seedlings.

    Science.gov (United States)

    Kim, Donggiun; Lee, Gunsup; Chang, Man; Park, Jongbum; Chung, Youngjae; Lee, Sukchan; Lee, Taek-Kyun

    2011-10-26

    Invertase (EC 3.2.1.26) catalyzes the hydrolysis of sucrose into D-glucose and D-fructose. Insoluble acid invertase (INAC-INV) was purified from pea (Pisum sativum L.) by sequential procedures entailing ammonium sulfate precipitation, ion exchange chromatography, absorption chromatography, reactive green-19 affinity chromatography, and gel filtration. The purified INAC-INV had a pH optimum of 4.0 and a temperature optimum of 45 °C. The effects of various concentrations of Tris-HCl, HgCl(2), and CuSO(4) on the activities of the purified invertase were examined. INAC-INV was not affected by Tris-HCl and HgCl(2). INAC-INV activity was inhibited by 6.2 mM CuSO(4) up to 50%. The enzymes display typical hyperbolic saturation kinetics for sucrose hydrolysis. The K(m) and V(max) values of INAC-INV were determined to be 4.41 mM and 8.41 U (mg protein)(-1) min(-1), respectively. INAC-INV is a true member of the β-fructofuranosidases, which can react with sucrose and raffinose as substrates. SDS-PAGE and immunoblotting were used to determine the molecular mass of INAC-INV to be 69 kDa. The isoelectric point of INAC-INV was estimated to be about pH 8.0. Taken together, INAC-INV is a pea seedling invertase with a stable and optimum activity at lower acid pH and at higher temperature than other invertases.

  9. Glass ceramics containment matrix for insoluble residues coming from spent fuel reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Pinet, O., E-mail: olivier.pinet@cea.fr; Boën, R.

    2014-04-01

    Spent fuel reprocessing by hydrometallurgical process generates insoluble residues waste streams called fines solution. Considering their radioactivity, fines solution could be considered as Intermediate Level Waste. This waste stream is usually mixed with fission products stream before vitrification. Thus fines are incorporated in glass matrix designed for High Level Waste. The withdrawal of fines from high level glass could decrease the volume of high level waste after conditioning. It could also decrease the reaction time between high level waste and additives to obtain a homogeneous melt and then increase the vitrification process capacity. Separated conditioning of fines in glass matrices has been tested. The fines content targeted value is 16 wt%. To achieve this objective, two types of glass ceramic formulations have been tested. 700 g of the two selected glass ceramics have been prepared using simulated fines. Additives used were ground glass. Melting is achieved at 1100 °C. According to the type of glass ceramic, reducing or oxidizing conditions have been performed during melting. Due to their composition and the melting redox conditions, different phases have been observed. These crystalline phases are typically RuO{sub 2}, metallic Ru, metallic Pd, MoO{sub 2} and CaMoO{sub 4}. In view of melting these matrices in an in can process the corrosiveness of one of the most oxidizing borosilicate glass ceramic formulation has been tested. This one has been remelted at 1100 °C in inconel 601 pot for 3 days. The oxygen fugacity measurement performed in the remelted glass leads to an oxidizing value, indicating that no significant reaction occurred between the inconel pot and the glass melt had occurred.

  10. The synthesis and application involving regulation of the insoluble drug release from mesoporous silica nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia, E-mail: ydlijia@163.com [School of Pharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016 (China); Wang, Yan, E-mail: wangyan6505@163.com [School of Pharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016 (China); Zheng, Xin, E-mail: 33682150@qq.com [School of Pharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016 (China); Zhang, Ying, E-mail: yzhang7704@sina.com [College of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016 (China); Sun, Changshan, E-mail: freescs@163.com [School of Pharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016 (China); Gao, Yikun, E-mail: 174913818@qq.com [School of Medical Devices, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016 (China); Jiang, Tongying, E-mail: jiangtongyingsy@163.com [School of Pharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016 (China); Wang, Siling, E-mail: silingwang@syphu.edu.cn [School of Pharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016 (China)

    2015-03-01

    Highlights: • Mesoporous silica nanotubes (SNT) were synthesized by using CNT as hard template, and the formation of the SNT shows that CTAB played a significant effect on the coating process. • The tube mesoporous silica materials which were seldom reported were applied in the drug delivery system to improve the loading amount and the drug dissolution. • The release rate could be controlled by the gelatin layer on the silica surface and the mechanism was illustrated. - Abstract: Mesoporous silica nanotubes (SNT) were synthesized using hard template carbon nanotubes (CNT) with the aid of cetyltrimethyl ammonium bromide (CTAB) in a method, which was simple and inexpensive. Scanning electron microscopy, transmission electron microscopy and specific surface area analysis were employed to characterize the morphology and structure of SNT, and the formation mechanism of SNT was also examined by Fourier transform infrared spectroscopy. There are few published reports of the mesoporous SNT with large specific surface area applied in the drug delivery systems to improve the amount of drug loading. In addition, the structure of SNT allows investigators to control the drug particle size in the pore channels and significantly increase the drug dissolution rate. The insoluble drug, cilostazol, was chosen as a model drug to be loaded into SNT and we developed a simple and efficient method for regulating the drug release by using a gelatin coating with different thicknesses around the SNT. The release rate was adjusted by the amount of gelatin surrounding the SNT, with an increased barrier leading to a reduction in the release rate. A model developed on the basis of the Weibull modulus was established to fit the release results.

  11. The effect of water on the mechanical properties of soluble and insoluble ceramic cements.

    Science.gov (United States)

    Koh, Ilsoo; López, Alejandro; Pinar, Ana B; Helgason, Benedikt; Ferguson, Stephen J

    2015-11-01

    Ceramic cements are good candidates for the stabilization of fractured bone due to their potential ease of application and biological advantages. New formulations of ceramic cements have been tested for their mechanical properties, including strength, stiffness, toughness and durability. The changes in the mechanical properties of a soluble cement (calcium sulfate) upon water-saturation (saturation) was reported in our previous study, highlighting the need to test ceramic cements using saturated samples. It is not clear if the changes in the mechanical properties of ceramic cements are exclusive to soluble cements. Therefore the aim of the present study was to observe the changes in the mechanical properties of soluble and insoluble ceramic cements upon saturation. A cement with high solubility (calcium sulfate dihydrate, CSD) and a cement with low solubility (dicalcium phosphate dihydrate, DCPD) were tested. Three-point bending tests were performed on four different groups of: saturated CSD, non-saturated CSD, saturated DCPD, and non-saturated DCPD samples. X-ray diffraction analysis and scanning electron microscopy were also performed on a sample from each group. Flexural strength, effective flexural modulus and flexural strain at maximum stress, lattice volume, and crystal sizes and shape were compared, independently, between saturated and non-saturated groups of CSD and DCPD. Although material dissolution did not occur in all cases, all calculated mechanical properties decreased significantly in both CSD and DCPD upon saturation. The results indicate that the reductions in the mechanical properties of saturated ceramic cements are not dependent on the solubility of a ceramic cement. The outcome raised the importance of testing any implantable ceramic cements in saturated condition to estimate its in vivo mechanical properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. From Commodity Polymers to Functional Polymers

    Science.gov (United States)

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications. PMID:24710333

  13. Interactions between solid surfaces mediated by polyethylene oxide polymers: effect of polymer concentration.

    Science.gov (United States)

    Wei, Xiaoling; Gong, Xiangjun; Ngai, To

    2013-09-03

    Using total internal reflection microscopy (TIRM), we have systematically measured the interactions between a microsphere and a flat hydrophilic surface in the presence of polyethylene oxide (PEO) polymer solution. Our results reveal that PEO significantly mediates the interaction forces between the two surfaces. At low polymer concentration, the interactions between two surfaces in the presence of PEO are mainly dominated by repulsive forces, originating from diffuse layer overlap. At intermediate polymer concentration, a long-range and weak attraction sets in. This force is likely attributed to the depletion attraction due to the presence of free PEO chains in bulk solution; however, a simple hard-sphere AO model fails to precisely describe the attraction. At high polymer concentration where PEO chains overlap, the attraction disappears, and levitation of the microsphere probe is detected. We argue that at this overlapping region, the correlation length of PEO chains is much smaller than the size of single PEO molecule, leading to weakening and disappearing of the depletion attraction. Finally, at very high concentration, oscillatory structural force is obviously found, indicating the significant structural ordering of the PEO chains under confinement.

  14. INTERFACIAL SELF-ASSEMBLY OF A SCHIZOPHYLLUM-COMMUNE HYDROPHOBIN INTO AN INSOLUBLE AMPHIPATHIC PROTEIN MEMBRANE DEPENDS ON SURFACE HYDROPHOBICITY

    NARCIS (Netherlands)

    WOSTEN, HAB; RUARDY, TG; VANDERMEI, HC; BUSSCHER, HJ; WESSELS, JGH

    1995-01-01

    Hydrophobins are small secreted fungal proteins rich in hydrophobic amino acids with a characteristic hydropathy pattern and conserved location of eight cysteine residues. It was previously shown that purified SC3p hydrophobin of Schizophyllum commune self-assembles at hydrophilic/hydrophobic

  15. Blends of hydrophobic and swelling agents in the swelling layer in the preparation of delayed-release pellets of a hydrophilic drug with low MW: Physicochemical characterizations and in-vivo evaluations

    Directory of Open Access Journals (Sweden)

    Chang You

    2014-08-01

    Full Text Available In this study, a hydrophobic material, ethylcellulose, which was used as its aqueous suspension Surelease®, was combined with a swelling agent as the swelling layer to prepare delayed-release pellets for Danshensu, which is a hydrophilic drug with low MW. A rupturable, delayed-release pellet consists of a drug core, a swelling layer containing a swelling agent (cross-linked sodium carboxymethyl cellulose with a hydrophobic agent (Surelease®, and a controlled layer composed by an insoluble, water-permeable polymeric coating (aqueous ethylcellulose dispersions was developed in a fluidised bed. Results showed that blending Surelease® into the swelling layer could effectively extend the release of Danshensu from the pellets, which may be attributed to the slowed swelling rate by reduction of water penetration and improvement of mechanical integrity of the swelling layer. Drug in the delayed pellets showed sustained release in beagle dogs after oral administration with comparable in-vivo exposure to the uncoated drug pellets. In conclusion, blends of hydrophobic and swelling agents in the swelling layer in double-membrane pellets could achieve a delayed drug-release profile in vitro, as well as delayed and sustained absorption in vivo for highly soluble, low-MW drug. The present study highlighted the potential use of a delayed-release system for other hydrophilic, low-MW drugs to meet the formulation requirements for chronopharmacological diseases.

  16. Design of freeze-dried Soluplus/polyvinyl alcohol-based film for the oral delivery of an insoluble drug for the pediatric use.

    Science.gov (United States)

    Shamma, Rehab; Elkasabgy, Nermeen

    2016-01-01

    Spironolactone (SL) is a poorly water-soluble drug. Being poorly soluble affects its dissolution rate which in turn affects its oral bioavailability. This work aimed to prepare freeze-dried SL-Soluplus/polyvinyl alcohol (PVA) oral thin film in an attempt to enhance the drug solubility on one hand and at the same time prepare a solid dosage form convenient for the pediatric use. SL-Soluplus/PVA films were prepared using polyethylene glycol 400 (PEG 400) as a plasticizer applying the solvent-casting technique. The prepared films were evaluated for their thickness, tensile strength, and in vitro dissolution studies. Box-Behnken design (17 runs) was applied to optimize the effects of the formulation variables on the film properties. The optimized film formulation was freeze-dried after casting so as to enhance the drug dissolution. Moreover, the optimized freeze-dried film was re-characterized in vitro and evaluated in vivo in human volunteers to investigate its palatability and satisfaction. The results showed that the optimized formulation composed of 10% polymer concentration containing Soluplus:PVA (0.33:0.66) and plasticized with 30% PEG 400 possessed the highest desirability value (0.836). Freeze-drying of the optimized formulation succeeded to improve SL in vitro dissolution due to the preparation of a more porous film compared to the non-freeze-dried one. In vivo evaluation of the optimized freeze-dried film showed high satisfaction among the participating volunteers concerning the ease of administration and sensation thereafter, where all the film specimens dissolved without the need for water and no film residues remained in the mouth following film dissolution. In conclusion, freeze-dried Soluplus®/PVA-based oral thin film proved to be a successful carrier for the oral delivery of insoluble drugs like SL for pediatrics.

  17. Effect of Grinding Methods on Structural, Physicochemical, and Functional Properties of Insoluble Dietary Fiber from Orange Peel

    Directory of Open Access Journals (Sweden)

    Yanlong Liu

    2016-01-01

    Full Text Available This study evaluated the effect of grinding methods (regular laboratory milling, ultra centrifugal rotor milling, and ball milling on structural, physicochemical, and functional properties of insoluble dietary fiber (IDF fraction from orange peel. The results demonstrated that both ultra centrifugal milling and ball milling could effectively decrease average particle size of IDF fraction (81.40 μm and 19.63 μm, resp.. The matrix structure of IDF fraction was destroyed but FTIR structure had no major change after grinding. As particle size decreased, the bulk density and lightness of IDF fraction increased and a redistribution of fiber components from insoluble to soluble fractions was observed. Furthermore, ball milled IDF fraction exhibited significantly higher capacity to retard glucose diffusion and inhibit α-amylase activity (35.09%. This work would give useful insight into effect of grinding methods on properties and functions of orange peel IDF in food industry.

  18. Data for discriminating dead/live bacteria in homogenous cell suspensions and the effect of insoluble substrates on turbidimetric measurements

    Directory of Open Access Journals (Sweden)

    Kwabena O. Duedu

    2017-06-01

    Full Text Available Estimation of bacterial growth by rapid traditional methods such as spectrophometric measurements at 600 nm (OD600 is not applicable for cultures containing insoluble particles in the growth media. Colony counts are the only suitable alternative but these are laborious and not high-throughput. The data presented in this article is related to the research article entitled “Two-colour fluorescence fluorimetric analysis for direct quantification of bacteria and its application in monitoring bacterial growth in cellulose degradation systems” (Duedu and French, 2017 [1]. This data article presents original primary data describing the discrimination of dead/live bacteria in homogenous cell suspensions and how the presence of insoluble substrates affect the turbidity of the suspensions.

  19. The Effects of Phosphate Solubilizing Rhizobacteria on Soybean (Glycine max. L. Plants Grown under Insoluble Phosphate Fertilization

    Directory of Open Access Journals (Sweden)

    Vladimir Rotaru

    2016-11-01

    Full Text Available The aim of this study was to assess the comparative efficacy of two phosphorus solubilizing rhizobacteria namely Burkholderia cepacia B36 and Enterobacter radicincitans D5/23T combined with insoluble phosphates in soybean (Glycine max. L.. Inoculated plants were grown in sand culture under controlled greenhouse conditions. All the inoculated treatments showed better plant growth and nutrient uptake when compared to uninoculated control. The inoculation with B. cepacia performed better than with E. radicincitans. Phosphorus concentrations in shoots and roots did not change significantly at the early stage of plant growth. However, the bacterial inoculation had better stimulatory effect on phosphorus uptake by soybean fertilized with insoluble phosphates, in particular in treatment with combined application of both bacteria strains.

  20. Thin film of Poly(acrylic acid-co-allyl acrylate as a Sacrificial Protective Layer for Hydrophilic Self Cleaning Glass

    Directory of Open Access Journals (Sweden)

    Jānis Lejnieks

    2010-05-01

    Full Text Available Poly(acrylic acid-co-allyl acrylate statistical copolymers were synthesized in a controlled manner in two steps: first tert.butyl acrylate and allyl acrylate were polymerized via atom transfer radical polymerization (ATRP and afterwords the tert.butyl protective groups were removed via hydrolysis. Samples of self cleaning glass (SCG were coated with thin films of poly(acrylic acid-co-allyl acrylate and cross-linked afterwards by UV irradiation (in the presence of a photoinitiator and an accelerator. Solution cast thin films were transparent and homogeneous before and after UV cross-linking. The irradiated samples were found to be hydrophilic (Θ < 20° and water insoluble. The coating prevented the spontaneous hydrophobization of the SCG by residual silicon exhaled from the sealing material. The TiO2 photocatalyst that covers the glass surface was found to strip the protective coating. The rate of the photooxidation process was measured by IR spectroscopy. The real field performance of the protective coating was also tested.

  1. Polymer and Membrane Design for Low Temperature Catalytic Reactions

    KAUST Repository

    Villalobos, Luis Francisco

    2016-02-29

    Catalytically active asymmetric membranes have been developed with high loadings of palladium nanoparticles located solely in the membrane\\'s ultrathin skin layer. The manufacturing of these membranes requires polymers with functional groups, which can form insoluble complexes with palladium ions. Three polymers have been synthesized for this purpose and a complexation/nonsolvent induced phase separation followed by a palladium reduction step is carried out to prepare such membranes. Parameters to optimize the skin layer thickness and porosity, the palladium loading in this layer, and the palladium nanoparticles size are determined. The catalytic activity of the membranes is verified with the reduction of a nitro-compound and with a liquid phase Suzuki-Miyaura coupling reaction. Very low reaction times are observed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. pH-switchable bacteria detection using zwitterionic fluorescent polymer.

    Science.gov (United States)

    Khoerunnisa; Mazrad, Zihnil A I; In, Insik; Park, Sung Young

    2017-04-15

    A zwitterionic fluorescent polymer with high sensitivity to pH changes was constructed for the detection and imaging of both gram-positive and gram-negative pathogenic bacteria. A detection probe using the zwitterionic fluorescent polymer was synthesized with single boron dipyrromethane (BODIPY) as a hydrophobic dye and bromoethane as a cationic group for bacteria binding with conjugated poly(sulfobetaine methacrylate) (BOD/BE-PSM). The zwitterionic fluorescent polymer bound to bacteria through ionic complexes between anionic groups on the bacterial surface and cationic BOD/BE-PSM groups after 1h incubation. This finding demonstrated that the fluorescence on/off system operated via changes in the hydrophilic and hydrophobic nature of the zwitterionic fluorescent polymer, depending on the pH (6.0, 7.4, or 9.0), at a fixed 1mg/mL polymer concentration. The system showed good stability with a limit of detection of 1mg/mL. Quenching caused by interactions with the hydrophobic BODIPY dye was also observed, enabling bacteria detection, as shown by fluorescence spectroscopy and confocal microscopy images. Our results indicated that the zwitterionic fluorescent polymer could be used to detect bacteria over a wide range of pH values. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Thermocleavable pi-Conjugated polymers. Synthesis and photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Helgesen, M.

    2009-10-15

    Polymer solar cells (plastic solar cells) have seen remarkable improvements in recent years where power conversion efficiencies of up to 6% have been reported for small area devices. However in terms of stability polymer solar cells degrade during illumination and in the dark leading to operational lifetimes that are generally very poor. There has been a recent interest in the operational stability of devices and more importantly on the understanding of why devices and materials break down. This has lead to the discovery of a new class of materials that enable exceptionally long device lifetimes (>20000 hours). This Ph.D. thesis describes the synthesis, characterization and photovoltaic applications of these novel polymer materials. A key feature of these materials is that solubilizing thermocleavable alkyl ester side chains are introduced on the polymer backbone. The side chains make the polymer soluble in organic solvents and allow film formation via solution processing. Subsequently they can be removed by heating in a post-processing step forming a harder insoluble material with enhanced stability. These new thermocleavable materials can potentially offer higher chromophore density, higher level processing and improved stability in a solar cell device. Methods are developed for the incorporation of alkoxy chains and thermocleavable ester groups on the benzothiadiazole and the thiophene units in an attempt to evolve the PDTBT system to a more advanced level. The synthesis and photovoltaic applications of the PDTTP and PDTBT systems is described. (author)

  4. β -Cyclodextrin polymer binding to DNA: Modulating the physicochemical parameters

    Science.gov (United States)

    Rocha, J. C. B.; Silva, E. F.; Oliveira, M. F.; Sousa, F. B.; Teixeira, A. V. N. C.; Rocha, M. S.

    2017-05-01

    Cyclodextrins and cyclodextrins-modified molecules have interesting and appealing properties due to their capacity to host components that are normally insoluble or poorly soluble in water. In this work, we investigate the interaction of a β -cyclodextrin polymer (poly-β -CD) with λ -DNA. The polymers are obtained by the reaction of β -CD with epichlorohydrin in alkaline conditions. We have used optical tweezers to characterize the changes of the mechanical properties of DNA molecules by increasing the concentration of poly-β -CD in the sample. The physical chemistry of the interaction is then deduced from these measurements by using a recently developed quenched-disorder statistical model. It is shown that the contour length of the DNA does not change in the whole range of poly-β -CD concentration (binding modes corresponding to the clustering of ˜2.6 and ˜14 polymer molecules along the DNA double helix, depending on the polymer concentration. Comparing these results with the ones obtained for monomeric β -CD, it was observed that the concentration of CD that alters the DNA persistence length is considerably smaller when in the polymeric form. Also, the binding constant of the polymer-DNA interaction is three orders of magnitude higher than the one found for native (monomeric) β -CD. These results show that the polymerization of the β -CD strongly increases its binding affinity to the DNA molecule. This property can be wisely used to modulate the binding of cyclodextrins to the DNA double helix.

  5. The Effects of Phosphate Solubilizing Rhizobacteria on Soybean (Glycine max. L.) Plants Grown under Insoluble Phosphate Fertilization

    OpenAIRE

    Vladimir Rotaru

    2016-01-01

    The aim of this study was to assess the comparative efficacy of two phosphorus solubilizing rhizobacteria namely Burkholderia cepacia B36 and Enterobacter radicincitans D5/23T combined with insoluble phosphates in soybean (Glycine max. L.). Inoculated plants were grown in sand culture under controlled greenhouse conditions. All the inoculated treatments showed better plant growth and nutrient uptake when compared to uninoculated control. The inoculation with B. cepacia performed better than w...

  6. Isolation and characterization of the Streptococcus mutans gtfC gene, coding for synthesis of both soluble and insoluble glucans.

    OpenAIRE

    Hanada, N; Kuramitsu, H K

    1988-01-01

    The intact gtfC gene from Streptococcus mutans GS-5 was isolated in Escherichia coli in plasmid vector pUC18. The glucosyltransferase activity expressed by the gene synthesized both low-molecular-weight water-soluble glucan and insoluble glucan in a primer-independent manner. Purification of the enzyme by procedures that minimize proteolytic digestion yielded a purified preparation with a molecular weight of 140,000. Insertional inactivation of the gtfC gene with a streptococcal erythromycin ...

  7. Increasing potassium (K release from K-containing minerals in the presence of insoluble phosphate by bacteria

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Sarikhani

    2016-03-01

    Full Text Available Introduction: Phosphorus and potassium are major essential macronutrients for biological growth and development. Application of soil microorganisms is one approach to enhance crop growth. Some bacteria are efficient in releasing K and solubilizing P from mineral sources but their behavior was not studied more in presence together. Materials and methods: In this study the ability of seven bacterial strains, including Pseudomonas putida P13, P. putida Tabriz, P. fluorescens Tabriz, P. fluorescens Chao, Pantoea agglomerans P5, Azotobacter sp. and Bacillus megaterium JK3 to release mineral K from muscovite and biotite with application of insoluble (Ca3(PO42 or soluble (Na2HPO4 P-sources was investigated. Nutrient Broth was used to prepare an overnight culture of bacteria to inoculate in Aleksandrov medium, which was used to study the dissolution of silicate minerals. It should be mentioned that Aleksandrov medium was used to determine the amount of released P from tricalcium phosphate (TCP while muscovite was added to the medium as a sole source of potassium. Concentration of P was determined spectrophotometrically by ammonium-vanadate-molybdate method and K was determined by flame photometry. Results: The insoluble P-source led to a significantly increased released K into assay medium (66%, and the net release of K from the biotite was significantly enhanced. Among bacterial strains, the highest mean of released K was observed with P. putida P13 which released more K (27% than the control. The amounts of released K from micas in the presence of insoluble and soluble phosphate by P. putida P13 were 8.25 and 4.87 mg/g, respectively. Discussion and conclusion: Application of insoluble phosphate could increase K release from mica minerals. The enhanced releasing of mineral K might be attributed to the release of organic acids from the bacteria, a mechanism which plays a pivotal role in solubilizing phosphate from inorganic source of phosphate.

  8. Water structuring and collagen adsorption at hydrophilic and hydrophobic silicon surfaces.

    Science.gov (United States)

    Cole, Daniel J; Payne, Mike C; Ciacchi, Lucio Colombi

    2009-12-28

    The adsorption of a collagen fragment on both a hydrophobic, hydrogen-terminated and a hydrophilic, natively oxidised Si surface is investigated using all-atom molecular dynamics. While favourable direct protein-surface interactions via localised contact points characterise adhesion to the hydrophilic surface, evenly spread surface/molecule contacts and stabilisation of the helical structure occurs upon adsorption on the hydrophobic surface. In the latter case, we find that adhesion is accompanied by a mutual fit between the hydrophilic/hydrophobic pattern within the protein and the layered water structure at the solid/liquid interface, which may provide an additional driving force to the classic hydrophobic effect.

  9. Flocculation of flotation tailings using thermosensitive polymers

    Directory of Open Access Journals (Sweden)

    Bogacz Wojciech

    2017-09-01

    Full Text Available The key feature of thermosensitive polymers is the reversible transition between the hydrophilic and hydrophopic forms depending on the temperature. Although the main research efforts are focused on their application in different kinds of drug delivery systems, this phenomenon also allows one to precisely control the stability of solid-liquid dispersions. In this paper research on the application of poly(N-isopropylacrylamide copolymers in processing of minerals is presented. In the experiments tailings from flotation plant of one of the coal mines of Jastrzębska Spółka Węglowa S.A. (Poland were used. A laser particle sizer Fritsch Analysette 22 was used in order to determine the Particle Size Distribution (PSD. It was proved that there are some substantial issues associated with the application of thermosensitive polymers in industrial practice which may exclude them from the common application. High salinity of suspension altered the value of Lower Critical Solution Temperature (LCST. Moreover, the co-polymers used in research proved to be efficient flocculating agents without any temperature rise. Finally, the dosage needed to achieve steric stabilization of suspension was greatly beyond economic justification.

  10. Microparticles prepared from sulfenamide-based polymers

    Science.gov (United States)

    D’Mello, Sheetal R.; Yoo, Jun; Bowden, Ned B.; Salem, Aliasger K.

    2015-01-01

    Polysulfenamides (PSN), with a SN linkage (RSNR2) along the polymer backbone, are a new class of biodegradable and biocompatible polymers. These polymers were unknown prior to 2012 when their synthesis and medicinally relevant properties were reported. The aim of this study was to develop microparticles as a controlled drug delivery system using polysulfenamide as the matrix material. The microparticles were prepared by a water-in-oil-in-water double emulsion solvent evaporation method. For producing drug-loaded particles, FITC-dextran was used as a model hydrophilic compound. At the optimal formulation conditions, the external morphology of the PSN microparticles was examined by scanning electron microscopy to show the formation of smooth-surfaced spherical particles with low polydispersity. The microparticles had a net negative surface charge (−23 mV) as analyzed by the zetasizer. The drug encapsulation efficiency of the particles and the drug loading were found to be dependent on the drug molecular weight, amount of FITC-dextran used in fabricating FITC-dextran loaded microparticles, concentration of PSN and surfactant, and volume of the internal and external water phases. FITC-dextran was found to be distributed throughout the PSN microparticles and was released in an initial burst followed by more continuous release over time. Confocal laser scanning microscopy was used to qualitatively observe the cellular uptake of PSN microparticles and indicated localization of the particles in both the cytoplasm and the nucleus. PMID:23862723

  11. Hydration-Induced Phase Separation in Amphiphilic Polymer Matrices and its Influence on Voclosporin Release

    Energy Technology Data Exchange (ETDEWEB)

    Khan, I. John [The State Univ. of New Jersey, Piscataway, NJ (United States); Murthy, N. Sanjeeva [The State Univ. of New Jersey, Piscataway, NJ (United States); Kohn, Joachim [The State Univ. of New Jersey, Piscataway, NJ (United States)

    2015-10-30

    Voclosporin is a highly potent, new cyclosporine -- a derivative that is currently in Phase 3 clinical trials in the USA as a potential treatment for inflammatory diseases of the eye. Voclosporin represents a number of very sparingly soluble drugs that are difficult to administer. It was selected as a model drug that is dispersed within amphiphilic polymer matrices, and investigated the changing morphology of the matrices using neutron and x-ray scattering during voclosporin release and polymer resorption. The hydrophobic segments of the amphiphilic polymer chain are comprised of desaminotyrosyl-tyrosine ethyl ester (DTE) and desaminotyrosyl-tyrosine (DT), and the hydrophilic component is poly(ethylene glycol) (PEG). Water uptake in these matrices resulted in the phase separation of hydrophobic and hydrophilic domains that are a few hundred Angstroms apart. These water-driven morphological changes influenced the release profile of voclosporin and facilitated a burst-free release from the polymer. No such morphological reorganization was observed in poly(lactide-co-glycolide) (PLGA), which exhibits an extended lag period, followed by a burst-like release of voclosporin when the polymer was degraded. An understanding of the effect of polymer composition on the hydration behavior is central to understanding and controlling the phase behavior and resorption characteristics of the matrix for achieving long-term controlled release of hydrophobic drugs such as voclosporin.

  12. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  13. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  14. Accumulation of solvent-soluble and solvent-insoluble antioxidant phenolics in edible bean sprouts: implication of germination

    Directory of Open Access Journals (Sweden)

    Ren-You Gan

    2016-08-01

    Full Text Available Background: Edible bean sprouts are popular fresh vegetables widely recognized for their nutritional quality. However, while their antioxidant capacity and phenolic composition in both solvent-soluble and solvent-insoluble extracts has not been systematically evaluated. Methods: The antioxidant capacity and phenolic composition in both solvent-soluble and solvent-insoluble fractions of 12 cultivars of edible bean sprouts were evaluated, and relationships of antioxidant capacity and total phenolic content were also analyzed. Results: Sprouts demonstrated a wide range of antioxidant capacity and total phenolic content, with lower but substantial antioxidant capacity and total phenolic content in the solvent-insoluble fractions. Highest levels were found in the green mung bean sprout. Phenolic compounds, such as catechin, ellagic acid, ferulic acid, gallic acid and p-coumaric acid were widely detected in these sprouts. Additionally, a positive correlation was discovered between antioxidant capacity and total phenolic content in these edible bean sprouts. Conclusions: Germination generally resulted in the accumulation of antioxidant phenolics in the most edible bean sprouts. Edible bean sprouts with high antioxidant phenolics can be valuable natural sources of dietary antioxidants for the prevention of oxidative stress-related chronic diseases.

  15. Numerical modeling of the transport to an intravascular bubble in a tube with a soluble/insoluble surfactant.

    Science.gov (United States)

    Ayyaswamy, Portonovo S; Zhang, Jie; Eckmann, David M

    2006-09-01

    Using a newly developed algorithm in conjunction with the front tracking scheme, we have evaluated the transport associated with a deformable bubble moving in a tube in the presence of a soluble or an insoluble surfactant. Such evaluations are useful to the understanding of gas embolism--a common syndrome for decompression sickness. Decompression sickness may be encountered in performing extravehicular activity during space exploration. The numerical evaluations indicate that as the location of the adsorptive interface gets closer to the vessel wall, the surfactant amount on the wall gets depleted. The implication is that the process by which a bubble occluding a vessel dislodges may depend both on the strength of the diffusivity of the surfactant and the adsorption process. More detailed study is needed to clarify this observation. The numerical results evaluated include Marangoni flow, which causes a bubble to propel out of its initial static location, and bubble motion in Poiseuille flow. The presence of a soluble/insoluble surfactant slows down the bubble motion. For identical surface concentrations of the surfactant, the effect of the presence of a soluble surfactant is more severe on the retardation of the bubble motion than that of an insoluble surfactant.

  16. Determination of insoluble soap in agricultural soil and sewage sludge samples by liquid chromatography with ultraviolet detection.

    Science.gov (United States)

    Cantarero, Samuel; Zafra-Gómez, Alberto; Ballesteros, Oscar; Navalón, Alberto; Vílchez, José L; Crovetto, Guillermo; Verge, Coral; de Ferrer, Juan A

    2010-11-01

    We have developed a new analytical procedure for determining insoluble Ca and Mg fatty acid salts (soaps) in agricultural soil and sewage sludge samples. The number of analytical methodologies that focus in the determination of insoluble soap salts in different environmental compartments is very limited. In this work, we propose a methodology that involves a sample clean-up step with petroleum ether to remove soluble salts and a conversion of Ca and Mg insoluble salts into soluble potassium salts using tripotassium ethylenediaminetetraacetate salt and potassium carbonate, followed by the extraction of analytes from the samples using microwave-assisted extraction with methanol. An improved esterification procedure using 2,4-dibromoacetophenone before the liquid chromatography with ultraviolet detection analysis also has been developed. The absence of matrix effect was demonstrated with two fatty acid Ca salts that are not commercial and are never detected in natural samples (C₁₃:₀ and C₁₇:₀). Therefore, it was possible to evaluate the matrix effect because both standards have similar environmental behavior (adsorption and precipitation) to commercial soaps (C₁₀:₀) to C₁₈:₀). We also studied the effect of the different variables on the clean-up, the conversion of Ca soap, and the extraction and derivatization procedures. The quantification limits found ranged from 0.4 to 0.8 mg/kg. The proposed method was satisfactorily applied for the development of a study on soap behavior in agricultural soil and sewage sludge samples. © 2010 SETAC.

  17. Blockade of the formation of insoluble ubiquitinated protein aggregates by EGCG3"Me in the alloxan-induced diabetic kidney.

    Directory of Open Access Journals (Sweden)

    Shuxian Cai

    Full Text Available BACKGROUND: Renal accumulation of reactive carbonyl compounds (RCCs has been linked to the progression of diabetic nephropathy. We previously demonstrated that carbonyl stress induces the formation of amino-carbonyl cross-links and sharply increases the content of β-sheet-rich structures, which is the seed of insoluble aggregates formation, and tea catechin (--epigallocatechin 3-gallate (EGCG can reverse this process in vitro and in vivo. In this study, methylated derivative (--epigallocatechin-3-O-(3-O-methyl-gallate (EGCG3"Me was hypothesized to neutralize carbonyl stress mediating the formation of insoluble ubiquitinated protein (IUP aggregates, and reduce the early development of diabetic nephropathy. METHODS AND RESULTS: Diabetes was induced in mice by intraperitoneally injecting alloxan monohydrate (200 mg/kg/d twice and administering EGCG3"Me by gavage for 15 d. Reagent case and western blot results showed that, in diabetic kidneys, the carbonyl proteins in the serum increased; and in insoluble protein fraction, 4-hydroxynonenal-modified proteins, IUP aggregates and p62 accumulated; FT-IR study demonstrated that the lipid content, anti-parallel β-sheet structure and aggregates increased. EGCG3"Me treatment could effectively reverse this process, even better than the negative control treatment. CONCLUSIONS: EGCG3"Me exhibiting anti-β-sheet-rich IUP aggregate properties, maybe represents a new strategy to impede the progression of diabetic nephropathy and other diabetic complications.

  18. Effects of insoluble and soluble dietary fiber on glycemic control in dogs with naturally occurring insulin-dependent diabetes mellitus.

    Science.gov (United States)

    Kimmel, S E; Michel, K E; Hess, R S; Ward, C R

    2000-04-01

    To evaluate the effects of diets differing in type and quantity of fiber on glycemic control in dogs with naturally occurring insulin-dependent diabetes mellitus. Prospective randomized crossover controlled trial. 7 dogs with well-regulated naturally occurring insulin-dependent diabetes mellitus. Dogs were fed 1 of 3 diets for 1 month each in 1 of 6 randomized diet sequences. Diets included a low-fiber diet (LF) and 2 high-fiber diets; 1 contained only insoluble fiber (HIF), and 1 contained soluble fiber in addition to insoluble fiber (HSF). Caloric intake was unchanged throughout the study. Glycemic control was assessed after each feeding trial by measuring serum fructosamine concentration and performing 5 serial measurements of blood glucose concentration every 2 hours after the morning feeding and insulin injection. Significant differences were not detected in body weight, required insulin dosage, or albumin concentration among dogs fed the HIF, HSF, and LF diets. Mean and maximum blood glucose concentrations and area under the blood glucose curve were significantly lower in dogs fed the HIF diet, compared with values in the same dogs fed the HSF or LF diet. Fructosamine concentration was significantly lower in dogs fed the HIF or HSF diet, compared with values in the same dogs fed the LF diet. In dogs with naturally occurring insulin-dependent diabetes mellitus, a dry, high insoluble-fiber diet may aid in glycemic control.

  19. Effect of extrusion processing on the soluble and insoluble fiber, and phytic acid contents of cereal brans.

    Science.gov (United States)

    Gualberto, D G; Bergman, C J; Kazemzadeh, M; Weber, C W

    1997-01-01

    The health benefits associated with dietary fiber have resulted in it now being used in virtually all food product categories, including many products which are manufactured using extrusion processing. The objective of the present study was to determine if extrusion processing affected phytic acid, and soluble and insoluble fiber contents. The effect of screw speeds of 50, 70, and 100% of maximum rotations per minute (% MRPM) on these components was investigated. A BI-EX Model DNDG-62/20D co-rotating intermeshing self-cleaning twin-screw extruder, manufactured by Bühlerag, CH-9240, Uzwil, Switzerland, was used to process wheat, oat and rice brans. It was found that extrusion did not affect the insoluble fiber content of wheat bran; however, a decrease in this component was observed in rice and oat brans. The effect on rice bran insoluble fiber was greatest at screw speeds of 50 and 70% MRPM. This occurred in oat bran at 50% MRPM. Soluble fiber content increased in all brans after extrusion, except ER100. For oat and rice bran soluble fibers, the greatest increase occurred at 50 and 70% MRPM, while for wheat bran this occurred at 70 and 100% MRPM. Extrusion did not affect the phytate content of the cereal brans.

  20. Decrease of insoluble glucan formation in Streptococcus mutans by co-cultivation with Enterococcus faecium T7 and glucanase addition.

    Science.gov (United States)

    Yu, Shin-Hye; Kwak, So-Hyung; Nguyen, Thi Thanh Hanh; Seo, Ye-Seul; Song, Chaeri; Mok, Il Kyoon; Kim, Doman

    2018-02-01

    To develop preventive canine oral health bio-materials consisting of probiotics and glucanase to reduce insoluble glucan and volatile sulfur compound formation. Co-cultivation of Enterococcus faecium T7 with Streptococcus mutans at inoculation ratio of 3:1 (v/v) resulted in 25% reduction in the growth of Streptococcus mutans. Amounts of soluble and insoluble glucans produced by S. mutans were decreased to 70 and 55%, respectively. Insoluble glucan was decreased from 0.6 µg/ml in S. mutans culture to 0.03 µg/ml in S. mutans co-cultivated with E. faecium T7 in the presence of Lipomyces starkeyi glucanase. Volatile sulfur compound, a main component of halitosis produced by Fusobacteria nucleatum, was decreased by co-cultivating F. nucleatum with E. faecium. E. faecium and glucanase can be combined as potentially active ingredients of oral care products for pets by reducing plaque-forming bacteria growth and their by-products that cause cavity and periodontal disease.

  1. Theoretical and computer simulation insights into stimuli-responsive polymer systems

    Science.gov (United States)

    Kisselev, Alexei M.

    The phase behavior of temperature-responsive polymers with tunable lower critical solution temperatures (LCST) and light-responsive polymers was explored using statistical mechanics and molecular dynamics (MD) simulations. The LCST in water of (ethylene oxide)/ethylene copolymers is tailored by their chemical composition, specifically by the balance of hydrophilic to hydrophobic groups in the polymer. For the first time, the general formalism of the lattice-fluid with hydrogen-bonding (LFHB) theory has been successfully applied to a water-polymer system, a type of system known to be particularly difficult from the modeling perspective. This theory, modified here to account for multiple types of hydrogen bonds, has been shown to be effective when making theoretical predictions as justified by comparison with experimental results. It has been shown that a successful implementation of the LFHB theory is contingent upon an effective numerical implementation, and a numerical algorithm has been developed that specifically targets the computational complexities associated with this model. The series of (ethylene oxide)/ethylene copolymers were studied further with the modified Flory-Huggins with hydrogen bonding (FHHB) approach. A comparative study of LFHB and FHHB theories was undertaken and their relative advantages and drawbacks were revealed. Both theoretical models were shown to be successful in describing the phase behavior of these systems, and the model parameters were found to be transferable between different homologous copolymer series. Expanding beyond temperature-responsive polymer solutions, systems that can potentially find applications in antifouling, drug delivery, and surfaces with switchable tackiness, we subsequently focused on a light-responsive polymer film systems that have applications in photolithography. Similarly to the temperatureresponsive solutions above, for photolithography light-responsive materials exposure to UV radiation triggers the

  2. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

  3. Early osseointegration to hydrophilic and hydrophobic implant surfaces in humans.

    Science.gov (United States)

    Lang, Niklaus P; Salvi, Giovanni E; Huynh-Ba, Guy; Ivanovski, Saso; Donos, Nikolaos; Bosshardt, Dieter D

    2011-04-01

    To evaluate the rate and degree of osseointegration at chemically modified moderately rough, hydrophilic (SLActive) and moderately rough, hydrophobic (SLA) implant surfaces during early phases of healing in a human model. The devices used for this study of early healing were 4 mm long and 2.8 mm in diameter and had either an SLActive chemically modified or a moderately rough SLA surface configuration. These devices were surgically installed into the retro-molar area of 49 human volunteers and retrieved after 7, 14, 28 and 42 days of submerged healing. A 5.2-mm-long specially designed trephine with a 4.9 mm inside diameter, allowing the circumferential sampling of 1 mm tissue together with the device was applied. Histologic ground sections were prepared and histometric analyses of the tissue components (i.e. old bone, new bone, bone debris and soft tissue) in contact with the device surfaces were performed. All device sites healed uneventfully. All device surfaces were partially coated with bone debris. A significant fraction of this bone matrix coating became increasingly covered with newly formed bone. The process of new bone formation started already during the first week in the trabecular regions and increased gradually up to 42 days. The percentage of direct contact between newly formed bone and the device (bone-to-implant contact) after 2 and 4 weeks was more pronounced adjacent to the SLActive than to the SLA surface (14.8% vs. 12.2% and 48.3% vs. 32.4%, respectively), but after 42 days, these differences were no longer evident (61.6% vs. 61.5%). While healing showed similar characteristics with bone resorptive and appositional events for both SLActive and SLA surfaces between 7 and 42 days, the degree of osseointegration after 2 and 4 weeks was superior for the SLActive compared with the SLA surface. © 2011 John Wiley & Sons A/S.

  4. EVALUATION OF SOLID PHASE MICROEXTRACTION FOR THE ANALYSIS OF HYDROPHILIC COMPOUNDS

    Science.gov (United States)

    Two commercially available solid phase microextractions (SPME) fibers, polyacrylate and carboxem/polydimethylsiloxane (PDMS), were evaluated for their ability to extract hydrophilic compounds from drinking water. Conditions, such as desorption time, desorption temperature, sample...

  5. Oxidized potato starch based thermoplastic films : Effect of combination of hydrophilic and amphiphilic plasticizers

    NARCIS (Netherlands)

    Niazi, Muhammad Bilal Khan; Broekhuis, Antonius A.

    Different combinations of hydrophilic (glycerol and water) and amphiphilic (isoleucine) plasticizers were studied in the production of thermoplastic starch (TPS) powders and films from oxidized potato starch. All powder samples had an irregular and shrivelled morphology. In all mixtures containing

  6. Hydrophilic Mineral Coating of Membrane Substrate for Reducing Internal Concentration Polarization (ICP) in Forward Osmosis.

    Science.gov (United States)

    Liu, Qing; Li, Jingguo; Zhou, Zhengzhong; Xie, Jianping; Lee, Jim Yang

    2016-01-22

    Internal concentration polarization (ICP) is a major issue in forward osmosis (FO) as it can significantly reduce the water flux in FO operations. It is known that a hydrophilic substrate and a smaller membrane structure parameter (S) are effective against ICP. This paper reports the development of a thin film composite (TFC) FO membrane with a hydrophilic mineral (CaCO3)-coated polyethersulfone (PES)-based substrate. The CaCO3 coating was applied continuously and uniformly on the membrane pore surfaces throughout the TFC substrate. Due to the intrinsic hydrophilicity of the CaCO3 coating, the substrate hydrophilicity was significantly increased and the membrane S parameter was reduced to as low as the current best of cellulose-based membranes but without the mechanical fragility of the latter. As a result, the ICP of the TFC-FO membrane could be significantly reduced to yield a remarkable increase in water flux without the loss of membrane selectivity.

  7. Dual hydrophilic and salt responsive schizophrenic block copolymers – synthesis and study of self-assembly

    NARCIS (Netherlands)

    Vasantha, Vivek Arjunan; Jana, Satyasankar; Lee, Serina Siew Chen; Lim, Chin-Sing; Teo, Serena Lay Ming; Parthiban, Anbanandam; Vancso, Gyula J.

    2015-01-01

    A new class of dual hydrophilic diblock copolymers (BCPs) possessing poly(ethylene glycol) (PEG) and zwitterionic polysulfabetaine (PSB) was synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. These BCPs formed schizophrenic micelles undergoing core–shell

  8. Utilizing ion-pairing hydrophilic interaction chromatography solid phase extraction for efficient glycopeptide enrichment in glycoproteomics

    DEFF Research Database (Denmark)

    Mysling, Simon; Palmisano, Giuseppe; Højrup, Peter

    2010-01-01

    Glycopeptide enrichment is a prerequisite to enable structural characterization of protein glycosylation in glycoproteomics. Here we present an improved method for glycopeptide enrichment based on zwitter-ionic hydrophilic interaction chromatography solid phase extraction (ZIC-HILIC SPE...

  9. Amsacrine analog-loaded solid lipid nanoparticle to resolve insolubility for injection delivery: characterization and pharmacokinetics

    Directory of Open Access Journals (Sweden)

    Fang YP

    2016-03-01

    in vivo pharmacokinetics study showed that amsacrine analog was rapidly distributed from the central compartment to the tissue compartments after intravenous delivery of amsacrine analog-loaded SLN. The biodistribution behavior demonstrated that amsacrine analog mainly accumulated in the lungs. Noninvasion in vivo imaging system images also confirmed that the drug distribution was predominantly localized in the lungs when IR-780-loaded SLN was used. Keywords: amsacrine analog, solid lipid nanoparticle, pharmacokinetics, biodistribution, water insolubility

  10. Process for converting sodium nitrate-containing, caustic liquid radioactive wastes to solid insoluble products

    Science.gov (United States)

    Barney, Gary S.; Brownell, Lloyd E.

    1977-01-01

    A method for converting sodium nitrate-containing, caustic, radioactive wastes to a solid, relatively insoluble, thermally stable form is provided and comprises the steps of reacting powdered aluminum silicate clay, e.g., kaolin, bentonite, dickite, halloysite, pyrophyllite, etc., with the sodium nitrate-containing radioactive wastes which have a caustic concentration of about 3 to 7 M at a temperature of 30.degree. C to 100.degree. C to thereby entrap the dissolved radioactive salts in the aluminosilicate matrix. In one embodiment the sodium nitrate-containing, caustic, radioactive liquid waste, such as neutralized Purex-type waste, or salts or oxide produced by evaporation or calcination of these liquid wastes (e.g., anhydrous salt cake) is converted at a temperature within the range of 30.degree. C to 100.degree. C to the solid mineral form-cancrinite having an approximate chemical formula 2(NaAlSiO.sub.4) .sup.. xSalt.sup.. y H.sub.2 O with x = 0.52 and y = 0.68 when the entrapped salt is NaNO.sub.3. In another embodiment the sodium nitrate-containing, caustic, radioactive liquid is reacted with the powdered aluminum silicate clay at a temperature within the range of 30.degree. C to 100.degree. C, the resulting reaction product is air dried eitheras loose powder or molded shapes (e.g., bricks) and then fired at a temperature of at least 600.degree. C to form the solid mineral form-nepheline which has the approximate chemical formula of NaAlSiO.sub.4. The leach rate of the entrapped radioactive salts with distilled water is reduced essentially to that of the aluminosilicate lattice which is very low, e.g., in the range of 10.sup.-.sup.2 to 10.sup.-.sup.4 g/cm.sup.2 -- day for cancrinite and 10.sup.-.sup.3 to 10.sup.-.sup.5 g/cm.sup.2 -- day for nepheline.

  11. Damage-free polymer surface modification employing inward-type plasma

    Science.gov (United States)

    Kanou, Ryo; Suga, Hiroshi; Utsumi, Hideyuki; Takahashi, Satoshi; Shirayama, Yuya; Watanabe, Norimichi; Petit, Stèphane; Shimizu, Tetsuo

    2017-08-01

    Inward-type plasmas, which spread upstream against the gas flow in the capillary tube where the gas is discharged, can react with samples placed near the entrance of such a capillary tube. In this study, surface modification of polymer surfaces is conducted using inward plasma. The modification is also done by conventional microplasma jet, and the modified surfaces with two plasma techniques are characterized by contact angle measurement, X-ray photoemission spectroscopy (XPS), and atomic force microscopy (AFM). Although inward-plasma-treated surfaces are less hydrophilic than conventional plasma-treated ones, they are still sufficiently hydrophilic for surface coatings. In addition, it turns out that the polymer surfaces irradiated with the inward plasma yield much smoother surfaces than those treated with the conventional plasma jet. Thus, the inward plasma treatment is a viable technique when the surface flatness is crucial, such as for the surface coating of plastic lenses.

  12. Interpolymer reactions of nonionic polymers with polyacrylic acid in aqueous solutions

    Directory of Open Access Journals (Sweden)

    E. Shaikhutdinov

    2012-03-01

    Full Text Available Results of fundamental investigations in the intermacromolecular reactions and interpolymer complexes to be performed by authors with co-workes within last 20 years have been intergrated and summarized in the present review. The raw of fundamental regularities in the effect of factors of different nature (pH, ionic strength, temperature, hydrophilic-hydrophobic balance of macrochain, etc. on the complexation of nonionic polymers with polycarboxylic acids in aqueous solutions has been revealed. Critical pH upon complexation (pHcrit. has been used for evaluation of the complexing ability of the polymers. It was shown tha tdepending on pHcrit. all systems can be divided into 2 groups, namely, weak complexing and strongly complexing. The existence of two critical pH upon complexation responsible for formation typical interpolymer complexes and hydrophilic associations has been demonstrated by the method of luminescence spectroscopy.

  13. Neutral, Charged and Stratified Polar Monoliths for Hydrophilic Interaction Capillary Electrochromatography

    OpenAIRE

    Gunasena, Dilani N.; El Rassi, Ziad

    2013-01-01

    Novel polar monoliths were introduced for hydrophilic interaction capillary electrochromatography (HI-CEC). In one case, a neutral polar monolith resulted from the in situ polymerization of glyceryl methacrylate (GMM) and pentaerythritol triacrylate (PETA) in a ternary porogenic solvent. GMM and PETA possess hydroxyl functional groups, which impart the monolith with hydrophilic interaction sites. This monolith is designated as hydroxy monolith. Although the hydroxy monolith is neutral and voi...

  14. Enhanced Permeation of a Hydrophobic Fluid through Particles with Hydrophobic and Hydrophilic Patterned Surfaces

    OpenAIRE

    Renliang Zhang; Yousheng Xu; Binghai Wen; Nan Sheng; Haiping Fang

    2014-01-01

    The wetting properties of solid surfaces are significant in oil/gas and liquid displacement processes. It is difficult for hydrophobic fluids to permeate channels filled with hydrophilic particles and an aqueous phase, and this is thought to be the primary cause of low yields in low permeability reservoir operations. Using three-dimensional lattice Boltzmann simulations, we show that particles with hydrophobic and hydrophilic patterned surfaces can greatly improve hydrophobic fluid permeation...

  15. Water-thinnable polymers for durable coatings for different materials

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, Piotr, E-mail: piotr.jankowski@ichp.pl; Kijowska, Dorota, E-mail: piotr.jankowski@ichp.pl [Industrial Chemistry Research Institute, Department of Polyesters, Epoxides and Polyurethanes, 8 Rydygiera Str., 01-793 Warszawa (Poland)

    2014-05-15

    The methods of obtaining water-thinnable polymers - water-thinnable unsaturated polyester resins (WTUPR) - by polycondensation were elaborate and optimized. As hydrophilic monomers different types of sulfonate monomers were used. The monomers, with sulfonate groups and other reactive groups, were obtained by sulfonation of organic compounds with satisfactory yield. All products were analyzed by {sup 1}H NMR and {sup 13}C NMR spectra. WTUPR were used as polymeric binders for coatings applications. Coatings with relatively high pendulum hardness, good properties and durability, useful for practical applications, were obtained. Typical existing equipment for the production of unsaturated polyester resins can be applied for the industrial preparation of WTUPR.

  16. Proton-Conducting Polymer Membrane Consisting of Cross-Linked Poly(2-hydroxyethyl methacrylate) with Nafion® for Fuel Cell Application.

    Science.gov (United States)

    Kim, Hee Jin; Talukdar, Krishan; Kabir, M D Lutful; Choi, Sang-June

    2018-08-01

    To increase the water retention and proton-conducting ability of Nafion®, we prepared a cross-linked polymer consisting of poly(2-hydroxyethyl methacrylate) (pHEMA) and Nafion®. pHEMA was chosen as a cross-linking polymer because it produces a water-insoluble but water-swellable polymer. Although it is hydrophobic, its water-swellable characteristic means that water will not be excluded from the polymer. Introduction of pHEMA into Nafion® prevents polymer solubility and provides structural stability and rigidity, which should in turn reduce the methanol permeability. Moreover, convenient permeability of pHEMA to cations makes it a good candidate for a hydrocarbon proton-conducting polymer tuned with Nafion®.

  17. Improvement in soil and sorghum health following the application of polyacrylate polymers to a Cd-contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Guiwei, Q. [Department of Agricultural and Environmental Chemistry, Instituto Superior de Agronomia, Technical University of Lisbon (TULisbon), Tapada da Ajuda, 1349-017 Lisboa (Portugal); Soil and Environmental College, Shenyang Agricultural University, 110161 Shenyang, Liaoning Province (China); Varennes, A. de, E-mail: adevarennes@isa.utl.pt [Department of Agricultural and Environmental Chemistry, Instituto Superior de Agronomia, Technical University of Lisbon (TULisbon), Tapada da Ajuda, 1349-017 Lisboa (Portugal); Martins, L.L.; Mourato, M.P.; Cardoso, A.I. [Department of Agricultural and Environmental Chemistry, Instituto Superior de Agronomia, Technical University of Lisbon (TULisbon), Tapada da Ajuda, 1349-017 Lisboa (Portugal); Mota, A.M. [Department of Chemical Engineering, Instituto Superior Tecnico, Technical University of Lisbon (TULisbon), Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Pinto, A.P. [Instituto de Ciencias Agrarias Mediterranicas (ICAM), University of Evora, R. Romao Ramalho no. 59, 7000 Evora (Portugal); Goncalves, M.L. [Department of Chemical Engineering, Instituto Superior Tecnico, Technical University of Lisbon (TULisbon), Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2010-01-15

    Contamination of soils with cadmium (Cd) is a serious global issue due to its high mobility and toxicity. We investigated the application of insoluble polyacrylate polymers to improve soil and plant health. Sorghum was grown in a Cd-contaminated sandy soil. Polyacrylate polymers at 0.2% (w/w) were added to half of the soil. Control soil without plants was also included in the experiment. Growth of sorghum was stimulated in the polymer-amended soil. The concentration of Cd in the shoots, and the activities of catalase and ascorbate peroxidase decreased in plants from polymer-amended soil compared with unamended control. The amount of CaCl{sub 2}-extractable Cd in the polymer-amended soil was 55% of that in the unamended soil. The Cd extracted in sorghum shoots was 0.19 mg per plant grown on soil without polymer and 0.41 mg per plant grown on polymer-amended soil. The total amount of Cd removed from each pot corresponded to 1.5 and more than 6% of soil CaCl{sub 2}-extractable Cd in unamended and polymer-amended soil, respectively. The activities of soil acid phosphatase, {beta}-glucosidase, urease, protease and cellulase were greatest in polymer-amended soil with sorghum. In conclusion, the application of polyacrylate polymers to reduce the bioavailable Cd pool seems a promising method to enhance productivity and health of plants grown on Cd-contaminated soils.

  18. Preparation and characterization of methacrylate-based monolith for capillary hydrophilic interaction chromatography.

    Science.gov (United States)

    Chen, Ming-Luan; Li, Li-Man; Yuan, Bi-Feng; Ma, Qiao; Feng, Yu-Qi

    2012-03-23

    In current study, poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EDMA) monolith was successfully prepared for capillary hydrophilic liquid chromatography (cHILIC). The polymerization was optimized by changing the ratio of MAA to EDMA, the type and amount of porogen. The characterization indicated that "hydrophilic" monolithic column possessed homogeneous column bed, good permeability and narrow pore size distribution. Under HILIC mode, the "hydrophilic" monolith prepared with PEG and DMSO showed stronger hydrophilicity than the "hydrophobic" monolith prepared with dodecanol and toluene. Finally, the "hydrophilic" monolith was applied in the separation of tryptic digests of bovine serum albumin (BSA) with cHILIC-ESI-qTOF-MS system. Our results revealed that 49 peptides were identified with 50% sequence coverage under HILIC mode, which was much better than the peptides identified using particulate-packed commercial column with RPLC-ESI-qTOF-MS system or "hydrophobic" monolith with cHILIC-ESI-qTOF-MS system. Taken together, the "hydrophilic" monolithic column prepared in current study, demonstrated the excellent chromatographic performance on the separation of complex samples, which offers the potential application of the monolith on proteomics study. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Drug-Polymer Electrostatic Complexes as New Structuring Agents for the Formation of Drug-Loaded Ordered Mesoporous Silica.

    Science.gov (United States)

    Molina, Emilie; Warnant, Jérôme; Mathonnat, Mélody; Bathfield, Maël; In, Martin; Laurencin, Danielle; Jérôme, Christine; Lacroix-Desmazes, Patrick; Marcotte, Nathalie; Gérardin, Corine

    2015-12-01

    Using aminoglycoside antibiotics as drug models, it was shown that electrostatic complexes between hydrophilic drugs and oppositely charged double-hydrophilic block copolymers can form ordered mesophases. This phase behavior was evidenced by using poly(acrylic acid)-block-poly(ethylene oxide) block copolymers in the presence of silica precursors, and this allowed preparing drug-loaded mesoporous silica directly from the drug-polymer complexes. The novel synthetic strategy of the hybrid materials is highly efficient, avoiding waste and multistep processes; it also ensures optimal drug loading and provides pH-dependence of the drug release from the materials.

  20. PLGA implants: How Poloxamer/PEO addition slows down or accelerates polymer degradation and drug release.

    Science.gov (United States)

    Hamoudi-Ben Yelles, M C; Tran Tan, V; Danede, F; Willart, J F; Siepmann, J

    2017-05-10

    The aim of this study was to evaluate the impact of the addition of small amounts of hydrophilic polymers (Poloxamer 188 and PEO 200kDa) to PLGA-based implants loaded with prilocaine. Special emphasis was placed on the importance of the type of preparation technique: direct compression of milled drug-polymer powder blends versus compression of drug loaded microparticles (prepared by spray-drying). The implants were thoroughly characterized before and upon exposure to phosphate buffer pH7.4, e.g. using optical and scanning electron microscopy, X-ray diffraction, DSC and GPC. Interestingly, the addition of Poloxamer/PEO to the PLGA implants had opposite effects on the resulting drug release kinetics, depending on the type of preparation method: in the case of implants prepared by compression of milled drug-polymer powder blends, drug release was accelerated, whereas it was slowed down when the implants were prepared by compression of drug loaded PLGA microparticles. These phenomena could be explained by the swelling/disintegration behavior of the implants upon exposure to the release medium. Systems consisting of compressed microparticles remained intact and autocatalytic effects were of major importance. The presence of a hydrophilic polymer facilitated water penetration into these devices, slowing down PLGA degradation and drug release. In contrast, implants consisting of compressed drug-polymer powder blends rapidly (at least partially) disintegrated and autocatalysis was much less important. In these cases, the addition of a hydrophilic polymer facilitated ester bond cleavage, leading to accelerated PLGA degradation and drug release. Copyright © 2017 Elsevier B.V. All rights reserved.