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Sample records for aqueous biphasic systems

  1. Metal separations using aqueous biphasic partitioning systems

    International Nuclear Information System (INIS)

    Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation

  2. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

    Science.gov (United States)

    Passos, Helena; Luís, Andreia; Coutinho, João A. P.; Freire, Mara G.

    2016-02-01

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  3. Selection of Xenobiotic-Degrading Microorganisms in a Biphasic Aqueous-Organic System

    OpenAIRE

    Ascon-Cabrera, Miguel; Lebeault, Jean-Michel

    1993-01-01

    Microbial selection on mixtures of chlorinated and nonchlorinated compounds that are poorly soluble in water and/or toxic to growing microbial cells was examined in both biphasic aqueous-organic and monophasic aqueous systems. A biphasic system in which silicone oil was used as the organic phase permitted the acceleration of acclimation, leading to rapid selection and to an increase in xenobiotic compound degradation. In contrast, acclimation, selection, and degradation were very slow in the ...

  4. Extraction of Biomolecules Using Phosphonium-Based Ionic Liquids + K3PO4 Aqueous Biphasic Systems

    OpenAIRE

    Louros, Cláudia L. S.; Cláudio, Ana Filipa M.; Neves, Catarina M. S. S.; Freire, Mara G.; Marrucho, Isabel M.; Jérôme Pauly; Coutinho, João A. P.

    2010-01-01

    Aqueous biphasic systems (ABS) provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs) to form ABS with aqueous K3PO4 solutions was evaluated for the first time. Ternary phase diagrams, and respective tie-lines and tie-lines length, formed by distinct phosphonium-based ILs, water, and K3PO4 at 298 K, we...

  5. Ionic liquid-salt based aqueous biphasic system separation of 109Cd from silver target

    International Nuclear Information System (INIS)

    The Aqueous Biphasic Systems (ABS) is becoming more important from green chemistry point of view replacing conventional liquid-liquid extraction system. The most of the aqueous biphasic systems reported in the literature are based on Polyethylene glycol (PEG) with different salts. Although ABS based on water soluble room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium Chloride ((bmim)CI) and concentrated solutions of kosmotropic salt K2HPO4 was reported in 2007 but the efficiency of this system for metal partitioning has been rarely explored. We report for the first time separation of no-carrier-added (NCA) 109Cd from the α-particle irradiated Ag target using this ABS

  6. Phase diagrams of ionic liquids-based aqueous biphasic systems as a platform for extraction processes

    International Nuclear Information System (INIS)

    Highlights: • Novel ABS based in ionic liquids were determined as a platform for distinct extraction processes. • The effect of pH, IL cation core, alkyl side chain length, IL anion nature, and salt nature on the ABS formation was investigated. • The ability to form ABS increases with the pH and alkyl chain length for all systems studied. • The ILs cation core and anion nature effect on the ABS formation is dominated by the IL (hydrophobic/hydrophilic) nature. • The effect of the different salts depends of the ionic liquid nature and salt valency. - Abstract: In the past few years, ionic liquid-based aqueous biphasic systems have become the subject of considerable interest as a promising technique for the extraction and purification of several macro/biomolecules. Aiming at developing guidelines for more benign and efficient extraction processes, phase diagrams for aqueous biphasic systems composed of ionic liquids and inorganic/organic salts are here reported. Several combinations of ionic liquid families (imidazolium, pyridinium, phosphonium, quaternary ammonium and cholinium) and salts [potassium phosphate buffer (KH2PO4/K2HPO4 at pH 7), potassium citrate buffer (C6H5K3O7/C6H8O7 at pH 5, 6, 7 and 8) and potassium carbonate (K2CO3 at pH ∼13)] were evaluated to highlight the influence of the ionic liquid structure (cation core, anion and alkyl chain length), the pH and the salt nature on the formation of aqueous biphasic systems. The binodal curves and respective tie-lines reported for these systems were experimentally determined at (298 ± 1) K. In general, the ability to promote the aqueous biphasic systems formation increases with the pH and alkyl chain length. While the influence of the cation core and anion nature of the ionic liquids on their ability to form aqueous biphasic systems closely correlates with ionic liquids capacity to be hydrated by water, the effect of the different salts depends of the ionic liquid nature and salt valency

  7. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    Energy Technology Data Exchange (ETDEWEB)

    K. Osseo-Asare; X. Zeng

    2002-01-01

    The objective of this research project is to develop an aqueous biphase extraction process for the treatment of fine coals. Aqueous biphase extraction is an advanced separation technology that relies on the ability of an aqueous system consisting of a water-soluble polymer and another component, e.g., another polymer, an inorganic salt, or a nonionic surfactant, to separate into two immiscible aqueous phases. The principle behind the partition of solid particles in aqueous biphase systems is the physicochemical interaction between the solid surface and the surrounding liquid solution. In order to remove sulfur and mineral matter from fine coal with aqueous biphasic extraction, it is necessary to know the partitioning behavior of coal, as well as the inorganic mineral components. Therefore, in this research emphasis was placed on the partitioning behavior of fine coal particles as well as model fine inorganic particles in aqueous biphase systems.

  8. Extraction of Biomolecules Using Phosphonium-Based Ionic Liquids + K3PO4 Aqueous Biphasic Systems

    Directory of Open Access Journals (Sweden)

    Cláudia L. S. Louros

    2010-04-01

    Full Text Available Aqueous biphasic systems (ABS provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs to form ABS with aqueous K3PO4 solutions was evaluated for the first time. Ternary phase diagrams, and respective tie-lines and tie-lines length, formed by distinct phosphonium-based ILs, water, and K3PO4 at 298 K, were measured and are reported. The studied phosphonium-based ILs have shown to be more effective in promoting ABS compared to the imidazolium-based counterparts with similar anions. Moreover, the extractive capability of such systems was assessed for distinct biomolecules (including amino acids, food colourants and alkaloids. Densities and viscosities of both aqueous phases, at the mass fraction compositions used for the biomolecules extraction, were also determined. The evaluated IL-based ABS have been shown to be prospective extraction media, particularly for hydrophobic biomolecules, with several advantages over conventional polymer-inorganic salt ABS.

  9. Poly(ionic liquid)s as phase splitting promoters in aqueous biphasic systems.

    Science.gov (United States)

    João, Karen G; Tomé, Liliana C; Isik, Mehmet; Mecerreyes, David; Marrucho, Isabel M

    2015-11-01

    Aqueous biphasic systems (ABSs) provide a sustainable and efficient alternative to conventional liquid-liquid extraction techniques with volatile organic solvents, and can be used for the extraction, recovery, and purification of diverse solutes. In this work, and for the first time, ABSs composed of poly(ionic liquid)s (PILs) and inorganic salts were measured at 25 °C and atmospheric pressure. New PILs having pyrrolidinium polycations combined with different counter-anions, namely acetate [Ac](-), trifluoroacetate [TFAc](-), hexanoate [Hex](-), adipate [Adi](-), and citrate [Cit](-) were synthesized, by a simple and environmentally-friendly procedure, and characterized. The effect of the PIL features, namely molecular weight and anionic character, and other experimental variables, such as temperature, on the phase splitting ability was researched. The aptitude of the studied ABS to be implemented as separation technologies was also evaluated through the use of a model biomolecule, tryptophan. PMID:26421939

  10. Modulating the Solubilities of Ionic Liquid Components in Aqueous-Ionic Liquid Biphasic Systems: A Q-NMR Investigation.

    Science.gov (United States)

    Atanassova, Maria; Mazan, Valérie; Billard, Isabelle

    2015-06-01

    Aqueous-ionic liquid (A-IL) biphasic systems have been examined in terms of deuterated water, acid, and IL cation and anion mutual solubilities in the upper (water-rich, in mole fraction) and lower phase of aqueous/IL biphasic systems at ambient temperature. The biphasic mixtures were composed of deuterated acids of various concentrations (mainly DCl, DNO(3), and DClO(4) from 10(-2) to 10(-4)  M) and five ionic liquids of the imidazolium family with a hydrophobic anion (CF(3)SO(2))(2) N(-), that is, [C1 Cn im][Tf(2)N], (n=2, 4, 6, 8 and 10). The analytical techniques applied were (1) H NMR, (19) F NMR, Karl-Fischer titration, pH potentiometry for IL cations and anions, and water and acid determination. The effects of the ionic strength (μ=0.1 M NaCl and NaNO(3) as well as μ=0.1 M, 0.2 M and 0.4 M NaClO(4), according to the investigated acid), the nature of the IL cation, and the nature of the mineral acid on the solubilities of the (D(2)O, D(+), Tf(2)N(-), C1 Cn im(+)) entities in the lower or upper phases were determined. The addition of sodium perchlorate was found to enhance the Tf(2)N(-) solubility while inhibiting the solubility of the ionic liquid cation. Differences in IL cation and anion solubilities of up to 42 mM were evidenced. The consequences for the characterization of the aqueous biphasic system, the solvent extraction process of the metal ions, and the ecological impact of the ILs are discussed. PMID:25787248

  11. Ionic liquids based aqueous biphasic systems: Effect of the alkyl chains in the cation versus in the anion

    International Nuclear Information System (INIS)

    Highlights: • Alkyl-3-methylimidazolium alkylsulfonate ILs for implemention of aqueous biphasic systems. • Study of the effect of alkyl chain length and position on ILs hydrophobicity. • Evaluation of ILs extractive power on L-tryptophan aqueous solutions. • The alkyl chain in the anion contributes more to the hydrophobicity of the IL. • Less hydrophobic ILs have the better extraction coefficients for L-tryptophan. -- Abstract: The use of alkyl-3-methylimidazolium alkylsulfonate ionic liquids for implementing aqueous biphasic systems is studied in this work for the first time. The ability of high charge density inorganic salts, such as K3PO4, to promote phase segregation in aqueous solutions containing the ionic liquids 1,3-dimethylimidazolium methylsulfonate ([C1mim][C1SO3]), 1-ethyl-3-methylimidazolium hexylsulfonate ([C2mim][C6SO3]), 1-ethyl-3-methylimidazolium butylsulfonate ([C2mim][C4SO3]), 1-butyl-3-methylimidazolium methylsulfonate ([C4mim][C1SO3]), 1-butyl-3-methylimidazolium ethylsulfonate ([C4mim][C2SO3]), 1-pentyl-3-methylimidazolium methylsulfonate ([C5mim][C1SO3]), 1-hexyl-3-methylimidazolium methylsulfonate ([C6mim][C1SO3]) and 1-hexyl-3-methylimidazolium ethylsulfonate ([C6mim][C2SO3]) was experimentally determined at 298.15 K and atmospheric pressure. In general, the hydrophobicity of the ionic liquids studied is affected by the increase of the alkyl chain length. However, the position of the alkyl chain, whether in the cation or in the anion affects in a different way the lipophilic effect of the ionic liquid. Two ionic liquids with the same number of carbon atoms, the one with a longer chain in the anion is the more hydrophobic. Furthermore, four ionic liquids were chosen to extract the aminoacid L-tryptophan from aqueous solutions. The chain lengths of the anion or cation were fixed and the partition coefficients compared. The extractions, carried out at 298.15 K, showed the good extractive power of these ionic liquids and also that

  12. Partition of lead in a milk-pectin aqueous biphasic system with complexing agents

    International Nuclear Information System (INIS)

    Aqueous two-phase systems allow partition of metal ions in nondenaturing conditions. From the fresh skim bovine milk spiked with 212Pb and agitated with 4% water solution of apple pectin (degree of esterification - 70%), less than 2.3% is recovered to the pectin phase and in the case of pasteurized milk less than 3.0%. Complexation with chelate forming agents was studied. Aminoacids as glycine, alanine and histidine do not exert influence on the yield, but the recovery in the pectin phase was 22% for cysteine, and 80% in the case of EdtacalTM (calcium salt of ethylenediaminetetraacetic acid). The retention of lead in milk phase is extraordinarily high as compared to strontium and corresponds to the behavior of trivalent ions. (author)

  13. Actinide recovery using aqueous biphasic extraction: Initial developmental studies

    International Nuclear Information System (INIS)

    Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less

  14. Actinide recovery using aqueous biphasic extraction: Initial developmental studies

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, D.J.; Mensah-Biney, R.; Mertz, C.J.; Rollins, A.N.

    1992-08-01

    Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less.

  15. Extraction, Preconcentration and Isolation of Flavonoids from Apocynum venetum L. Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with an Aqueous Biphasic System

    OpenAIRE

    Zhijian Tan; Yongjian Yi; Hongying Wang; Wanlai Zhou; Chaoyun Wang

    2016-01-01

    Background: Ionic liquids (ILs) are considered as green solvents, and widely applied for the extraction of various compounds. Methods: The present research focuses on the extraction of flavonoids from Apocynum venetum L. leaves by ultrasound-assisted extraction (UAE). Several major influencing factors were optimized. Then, an aqueous biphasic system (ABS) was applied for further isolation of flavonoids. Results: The flavonoids were mainly distributed in the top phase, while impurities were ex...

  16. Carbon nanohybrids used as catalysts and emulsifiers for reactions in biphasic aqueous/organic systems

    Institute of Scientific and Technical Information of China (English)

    Daniel E. Resasco

    2014-01-01

    This mini-review summarizes some novel aspects of reactions conducted in aqueous/organic emul-sions stabilized by carbon nanohybrids functionalized with catalytic species. Carbon nanohybrids represent a family of solid catalysts that not only can stabilize water-oil emulsions in the same fash-ion as Pickering emulsions, but also catalyze reactions at the liquid/liquid interface. Several exam-ples are discussed in this mini-review. They include (a) aldol condensation-hydrodeoxygenation tandem reactions catalyzed by basic (MgO) and metal (Pd) catalysts, respectively; (b) Fischer-Tropsch synthesis catalyzed by carbon-nanotube-supported Ru;and (c) emulsion polymerization of styrene for the production of conductive polymer composites. Conducting these reactions in emul-sion generates important advantages, such as increased liquid/liquid interfacial area that conse-quently means faster mass transfer rates of molecules between the two phases, effective separation of products from the reaction mixture by differences in the water-oil solubility, and significant changes in product selectivity that can be adjusted by modifying the emulsion characteristics.

  17. Partition of lead in milk-pectin aqueous biphasic system with complexation agents

    International Nuclear Information System (INIS)

    In present work, decontamination of raw cow milk from lead was investigated using the 'membraneless dialysis'. The 4% w/w solutions of apple pectin, degree of esterification 70%, containing various complexing agents were used for experiments at the initial volume ration pectin : milk = 3:7 which changed to 8:2 at equilibration. Radioactive indicator 212Pb was prepared from 228Th emanator. After dissolution in Jennes-Koops buffer with 10-5 M Pb2+ carrier, milk was spiked with the indicator for 100 minutes. Distribution equilibrium of water and lead was achieved after next 100 minutes but yield of lead extraction into pectin phase was less then 2.3% in the case of raw milk, and less then 3.0% in the case of pasteurized milk. Due to denaturation of raw milk, there are strongly limited possibilities to influence the radionuclide partition in the systems. Various non-toxic complexation agents (glycine, alanine, histidine, cysteine, Edtacal) were applied to improve extraction of lead to pectin phase. Glycine and histidine have not influence on lead extraction yields but there was observed an increased yield, 3,8% for alanine and even 25% for 0.002 M cysteine. As the most interesting appeared application of Edtacal, calcium salt of ethylenediaminetetraacetic acid, EDTA by which the recovery of lead with with pectin phase reached about 80% at concentration of EDTA in initial pectin phase 0.001 M. The retention of Pb2+ cation in milk phase is extraordinary high as compared with strontium and corresponds to behavior of trivalent ions what is attributed to specific interactions with thiol groups of milk components

  18. Search for a new greener technology for separation of NCA 97Ru from bulk Nb: ionic liquid based aqueous biphasic system

    International Nuclear Information System (INIS)

    Ionic-liquid (IL) based aqueous biphasic system was developed for the separation of no-carrier-added (NCA) 97Ru from bulk niobium target for the first time as greener separation technology. Room temperature ionic liquid, 1-butyl-3-methylimidazolium Chloride ((Bmim)Cl) against K2HPO4 as salt rich phase was employed to construct this IL-ABS system. In the typical experimental condition, 50 % NCA 97Ru was extracted into the ionic liquid phase without any contamination of Nb, with a separation factor of 5.3x103. (author)

  19. Solvent extraction studies on Th(IV) and U(VI) using polyethylene glycol (PEG) based aqueous biphasic system (ABS) with 18-crown-6

    International Nuclear Information System (INIS)

    Extraction of Th(IV) and U(VI) using PEG-2000/(NH4)2SO4 (40% w/w of each) aqueous biphasic system (ABS) with 18-crown-6 (18-C-6) as the extractant was studied at four fixed temperatures in the range 288 to 318 K. The species extracted were identified to be [Th . (18-C-6)](SO4)2 and [UO2 . (18-C-6)]SO4 by the slope ratio method. The equilibrium constant (K) was evaluated for the extraction reactions. The thermodynamic parameters evaluated by the temperature coefficient method at 298 K showed that the reaction is favoured by decrease in enthalpy and counteracted by decrease in entropy. The large decrease in the enthalpy values was attributed to direct bonding of crown ether to the central metal atom (i.e. the formation of inner sphere complex). (orig.)

  20. Liquid-Phase Synthesis of Ba2V2O7 Phosphor Powders and Films Using Immiscible Biphasic Organic-Aqueous Systems.

    Science.gov (United States)

    Takahashi, Mami; Hagiwara, Manabu; Fujihara, Shinobu

    2016-08-15

    A liquid-phase synthesis of inorganic phosphor materials at a moderate temperature was proposed by using immiscible liquid-liquid biphasic systems. A self-activated Ba2V2O7 phosphor was actually synthesized from vanadium alkoxide dissolved in an organic solution and barium acetate in an aqueous solution. A mild hydrolysis reaction of the alkoxide started at the organic-inorganic interface, and an intermediate compound, Ba(VO3)2·H2O, was initially formed. Ba2V2O7 powders were then obtained by the conversion from Ba(VO3)2·H2O promoted in the aqueous solution. Ba2V2O7 films were obtained on surface-modified silica glass substrates through the similar chemical reactions. Factors such as the surface state of substrates, the kind of organic solvents, and the volume of aqueous solutions were examined to improve the film deposition behavior. The resultant Ba2V2O7 materials showed broad-band visible photoluminescence upon irradiation with ultraviolet light based on the charge transfer transition in the VO4(3-) units existing as dimers. PMID:27472450

  1. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    Energy Technology Data Exchange (ETDEWEB)

    K. Osseo-Asare; X. Zeng

    2001-06-30

    Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. The partitioning behaviors of hematite in the dextran (Dex)/Triton X-100 (TX100) and polyethylene glycol (PEG)/dextran systems were investigated and the effects of some ionic surfactants on solid partition were studied. In both biphase systems, the particles stayed in the bottom dextran-rich phase under all pH conditions. This behavior is attributable to the fact that the hydrophilic oxide particles prefer the more hydrophilic bottom phase. Also, the strong favorable interaction between dextran and ferric oxide facilitates the dispersion of the solids in the polysaccharide-rich phase. In the Dex/TX100 system, addition of sodium dodecylsulfate (SDS) or potassium oleate had no effect on the solid partition; on the other hand, addition of dodecyltrimethylammonium bromide (DTAB) transferred the particles to the top phase or interface at high pH values. In the PEG/Dex system, the preferred location of hematite remained the bottom phase in the presence of either SDS or DTAB. The effects of anionic surfactants on the partition behavior are attributable to the fact that they are not able to replace the strongly adsorbed polysaccharide layer on the ferric oxide surface. The results with the cationic surfactant are due to electrostatic interaction between the cationic surfactant and the charged surface of the solid particles. The difference in solids partitioning in the two systems is the result of the different distribution of DTAB in these systems. In the Dex/TX100 system, DTAB prefers the top surfactant-rich phase, while it concentrates in the bottom phase in the PEG/dextran system.

  2. Biphasic catalysis in water/carbon dioxide micellar systems

    Science.gov (United States)

    Jacobson, Gunilla B.; Tumas, William; Johnston, Keith P.

    2002-01-01

    A process is provided for catalyzing an organic reaction to form a reaction product by placing reactants and a catalyst for the organic reaction, the catalyst of a metal complex and at least one ligand soluble within one of the phases of said aqueous biphasic system, within an aqueous biphasic system including a water phase, a dense phase fluid, and a surfactant adapted for forming an emulsion or microemulsion within the aqueous biphasic system, the reactants soluble within one of the phases of the aqueous biphasic system and convertible in the presence of the catalyst to a product having low solubility in the phase in which the catalyst is soluble; and, maintaining the aqueous biphasic system under pressures, at temperatures, and for a period of time sufficient for the organic reaction to occur and form the reaction product and to maintain sufficient density on the dense phase fluid, the reaction product characterized as having low solubility in the phase in which the catalyst is soluble.

  3. Alternative (Potentially Green) Separations Media: Aqueous Biphasic and Related Systems Extending the Frontier Final Report For Period September 1, 2002 January 31, 2007

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Robin D

    2007-06-25

    Through the current DoE-BES funding, we have extended our fundamental understanding of the critical phase separation of aqueous polymer solutions at the molecular level, and have developed a similar understanding of their application as novel solvent systems. Our principal aims included mode of delivery of the aqueous biphasic system (ABS) solvent system and the application of this system to problems of reactive extraction. In the former case we have developed novel solid phase analogues, in the form of cross-linked polyethylene glycol hydrogels, and in the latter case we have examined the role that ABS might play in reaction engineering, with a view to greener, simpler, and safer processes. We have also developed a new salt/salt ABS and have extended our understanding of this system as well. The major outcomes are as follows: (1) Through the use of variable temperature phase diagrams, coupled with differential scanning calorimetry (DSC) measurements of the phases, a better understanding of the thermodynamics of phase formation was obtained. Evidence to the existence and role of an upper critical solution temperature (UCST) or lower critical solution temperature (LCST) (or both) in these systems was gained. With variable temperature solute partitioning, thermodynamic parameters were calculated, and inter-system comparisons were made. Through the use of Abraham's linear solvation energy regression (LSER) the solvent-solute properties of liquid/liquid ABS were examined. We have shown that ABS are indeed very tunable and LSERs have been used as a tool to compare these systems to traditional organic/water and other liquid/liquid systems. (2) We have successfully shown the development of novel reaction media for chemical synthesis and reaction; Aqueous Biphasic Reactive Extraction (ABRE). As a proof of concept, we have shown the synthesis of adipic acid from cyclohexene in an ABS, which represents an important development in the exploitation of this technology

  4. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    Energy Technology Data Exchange (ETDEWEB)

    K. Osseo-Asare

    2000-06-02

    Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. The partitioning behavior of fly ash in the PEG-2000 Na{sub 2}SO{sub 4}/H{sub 2}O system was studied and the solid in each fraction was characterized by CHN analysis (carbon content), X-ray diffraction (XRD; crystal component), and inductively coupled plasma spectrophotometry (ICP; elemental composition in the ash). In the pH range from 2 to 5, the particles separated into two different layers, i.e., the polymer-rich (top) and salt-rich (bottom) layers. However, above pH 5, the particles in the polymer-rich phase split into two zones. The percent carbon content of the solids in the upper zone ({approximately}80 wt%) was higher than that in the parent sample (63.2 wt%), while the lower zone in the polymer-rich phase had the same percent ash content as the original sample. The particles in the salt-rich phase were mainly composed of ash (with < 4 wt% carbon content). However, when the solid concentration in the whole system increased from 1 wt% to 2 wt%, this 3-fraction phenomenon only occurred above pH 10. XRD results showed that the main crystal components in the ash included quartz, hematite, and mullite. The ICP results showed that Si, Al, and Fe were the major elements in the fly ash, with minor elements of Na, K, Ca, Mg, and Ba. The composition of the ash in the lower zone of the polymer-rich phase remained almost the same as that in the parent fly ash. The largest amount of product ({approximately}60% yield) with the highest carbon content ({approximately}80 wt% C) was obtained in the range pH 6-9. Based on the experimental results obtained, a flowsheet is proposed for the beneficiation of high-carbon fly ash with the aqueous biphase extraction process.

  5. Speciation of native cations and added radionuclides in raw bovine milk. I. membraneless dialysis in aqueous biphasic systems

    International Nuclear Information System (INIS)

    Partition of native sodium, potassium, magnesium, calcium and radioisotopes of cesium, strontium and europium was investigated in the aqueous liquid-liquid systems formed after agitation of fresh pasteurized skim bovine milk with 4% w/w water solution of pectin of various degree of esterification (60-93%). The partition of the ions in the 'membraneless dialysis' was described by Donnan equilibria and ion-exchange in the macro-and microheterogenous systems and, within uncertainty of results, does not depend on the degree of esterification. Strong negative non-ideality of Sr and Eu in milk phase is attributed to binding with proteins, casein particles in particular, and complexation with low molecular ligands. Separation factor α = D(Sr)/D(Ca) is 0.70 ±0.06, in favor of strontium concentration in pectin phase. While>96% of cesium is diffusible to pectin phase, only 43-56% (depending on physico-chemical model of dialysis) of strontium behaves in that way, and in original milk phase the percent of strontium cationic from may be as low as 13%. (author). 24 refs., 8 figs., 4 tabs

  6. ABEC trademark resins: From aqueous biphasic novelties to selective aqueous biphasic extraction chromatographic resins for metal ions

    International Nuclear Information System (INIS)

    We have recently been allowed patents on the use of polyethylene glycol-grafted resins for chaotropic metal ion separations based on the concepts of aqueous biphasic extraction. The concept and realization of the technology was developed by collaborative research between university and national laboratories. Commercialization of the technology was accomplished by licensing the technology to a specialty separations company itself started based on the foundation of technology transfer. This tripartite interaction was facilitated by the joint interest and membership of all involved parties in the Industrial ampersand Engineering Chemistry Division. This presentation will highlight the research which led to the adaptation of aqueous biphasic partitioning to ABEC trademark resins for metal ion separations. The role of the I ampersand EC Division and its Separation Science ampersand Technology Subdivision in facilitating such technology transfer will also be discussed

  7. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    Energy Technology Data Exchange (ETDEWEB)

    K. Osseo-Asare; X. Zeng

    2001-06-30

    Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. The partitioning behaviors of silica in the polyethylene glycol (PEG)/dextran (Dex) and dextran/Triton X-100 (TX100) systems have been investigated, and the effects of sodium dodecylsulfate (SDS) and dodecyltrimethylammonium bromide (DTAB) on solid partition have been studied. In both biphase systems, silica particles stayed in the top PEG-rich phase at low pH. With increase in pH, the particles moved from the top phase to the interface, then to the bottom phase. At very high pH, the solids preferred the top phase again. These trends are attributable to variations in the polymer/solid and nonionic surfactant/solid interactions. Addition of ionic surfactants into these two systems introduces a weakly charged environment, since ionic surfactants concentrate into one phase, either the top phase or the bottom phase. Therefore, coulombic forces also play a key role in the partition of silica particles because electrostatic attractive or repulsive forces are produced between the solid surface and the ionic-surfactant-concentrated phase. For the PEG/dextran system in the presence of SDS, SiO{sub 2} preferred the bottom dextran-rich phase above its pH{sub PZC}. However, addition of DTAB moved the oxide particles from the top phase to the interface, and then to the bottom phase, with increase in pH. These different behaviors are attributable to the fact that SDS and DTAB concentrated into the opposite phase of the PEG/dextran system. On the other hand, in the dextran/Triton X-100 system, both ionic surfactants concentrated in the top surfactant-rich phase and formed mixed micelles with TX100. Therefore, addition of the anionic surfactant, SDS, moved the silica particles from top phase to the

  8. A method for separating water soluble organics from a process stream by aqueous biphasic extraction

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, David J.; Mego, William A.

    1997-12-01

    The present invention relates to a method for separating water-miscible organic species from a process stream by aqueous biphasic extraction. In particular, the method includes extracting the organic species into a polymer-rich phase of an aqueous biphase system in which the process stream comprises the salt-rich phase, and, next, separating the polymer from the extracted organic species by contacting the loaded, polymer-rich phase with a water-immiscible organic phase. Alternatively, the polymer can be separated from the extracted organic species by raising the temperature of the loaded, polymer-rich phase above the cloud point, such that the polymer and the water-soluble organic species separate into two distinct aqueous phases. In either case, a substantially salt-free, concentrated aqueous solution containing the organic species is recovered.

  9. Extraction, Preconcentration and Isolation of Flavonoids from Apocynum venetum L. Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with an Aqueous Biphasic System

    Directory of Open Access Journals (Sweden)

    Zhijian Tan

    2016-03-01

    Full Text Available Background: Ionic liquids (ILs are considered as green solvents, and widely applied for the extraction of various compounds. Methods: The present research focuses on the extraction of flavonoids from Apocynum venetum L. leaves by ultrasound-assisted extraction (UAE. Several major influencing factors were optimized. Then, an aqueous biphasic system (ABS was applied for further isolation of flavonoids. Results: The flavonoids were mainly distributed in the top phase, while impurities were extracted to the bottom phase. The parameters influencing the extraction, namely type and concentration of salt, temperature, and pH, were studied in detail. Under optimized conditions (72.43% IL extract, 28.57% (NH42SO4, 25 °C temperature, pH 4.5, the preconcentration factor and extraction efficiency were found to be 3.78% and 93.35%, respectively. Conclusions: This simple and efficient methodology is expected to see great use in the extraction and isolation of pharmaceutically active components from medicinal plant resources.

  10. Application of PEG based aqueous biphasic systems in extraction and separation of no-carrier-added {sup 183}Re from bulk tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, B.; Lahiri, S. [Saha Institute of Nuclear Physics, Kolkata (India); Tomar, B.S. [Bhabha Atomic Research Centre, Mumbai (India). Radioanalytical Chemistry Div.

    2013-03-01

    No-carrier-added (nca) rhenium isotopes ({sup 182,182m,183}Re) were produced by irradiation with 30 MeV alpha particles on natural tantalum target. The short-lived {sup 182,182m}Re were allowed to decay and long-lived nca {sup 183}Re was separated from bulk tantalum matrix by aqueous biphasic system (ABS) using 2 M solutions of nine different salts, namely, Na{sub 2}SO{sub 4}, Na2SO{sub 3}, NaHSO{sub 3}, Na{sub 2}S{sub 2}O{sub 3}, Na{sub 2}HPO{sub 4}, Na{sub 2}CO{sub 3}, Na-citrate, Na-tartrate, and (NH{sub 4}){sub 2}SO{sub 4} as salt rich phases against 50% (w/w) PEG-4000 as polymer rich phase at room temperature. The influence of temperature and thermodynamic parameters {Delta} H and {Delta} S were obtained for the partition of {sup 183}Re and tantalum in these systems. Nca {sup 183}Re was extracted in high amount in polymer rich phases irrespective of the salt rich phases. Bulk tantalum showed tendency to remain in salt rich phases. ABSs with PEG-4000 polymer rich phase in combination with Na{sub 2}SO{sub 4}, Na{sub 2}SO{sub 3}, NaHSO{sub 3}, Na{sub 2}HPO{sub 4}, Na{sub 2}CO{sub 3}, Na-citrate and Na-tartrate as salt rich phases at basic pH and at ambient temperature (27 C) offered single-step separation between nca {sup 183}Re and bulk Ta. When Na{sub 2}S{sub 2}O{sub 3} and (NH{sub 4}){sub 2}SO{sub 4} were used as salt rich phase, slight extraction of bulk tantalum was observed in PEG-4000 rich phase. The dynamic dissociation constant of {sup 183}Re-PEG-4000 complex was measured by dialysis of the PEG-rich phase against de-ionised water. The k{sub dissociation} value was found as low as 0.0185 min{sup -1}. Therefore, it is possible to have pure {sup 183}Re in de-ionized water immediately after the dialysis. (orig.)

  11. A Framework for the Modelling of Biphasic Reacting Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Sin, Gürkan; O’Connell, John P.;

    2014-01-01

    Biphasic reacting systems have a broad application range from organic reactions in pharmaceutical and agro-bio industries to CO 2 capture. However, mathematical modelling of biphasic reacting systems is a formidable challenge due to many phenomena underlying the process such as chemical equilibrium......, biphasic equilibrium, reaction kinetics, and transport/mixing. In this study, a framework for modelling biphasic reacting systems is proposed to fa cilitate the model development in support of model-based process design-analysis. This framework is successfully applied to describe two biphasic reaction...

  12. Aqueous biphasic extraction of uranium and thorium from contaminated soils. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, D.J.; Gartelmann, J.; Henriksen, J.L.; Krause, T.R.; Deepak; Vojta, Y.; Thuillet, E.; Mertz, C.J.

    1995-07-01

    The aqueous biphasic extraction (ABE) process for soil decontamination involves the selective partitioning of solutes and fine particulates between two immiscible aqueous phases. The biphase system is generated by the appropriate combination of a water-soluble polymer (e.g., polyethlene glycol) with an inorganic salt (e.g., sodium carbonate). Selective partitioning results in 99 to 99.5% of the soil being recovered in the cleaned-soil fraction, while only 0.5 to 1% is recovered in the contaminant concentrate. The ABE process is best suited to the recovery of ultrafine, refractory material from the silt and clay fractions of soils. During continuous countercurrent extraction tests with soil samples from the Fernald Environmental Management Project site (Fernald, OH), particulate thorium was extracted and concentrated between 6- and 16-fold, while the uranium concentration was reduced from about 500 mg/kg to about 77 mg/kg. Carbonate leaching alone was able to reduce the uranium concentration only to 146 mg/kg. Preliminary estimates for treatment costs are approximately $160 per ton of dry soil. A detailed flowsheet of the ABE process is provided.

  13. Aqueous biphasic extraction of uranium and thorium from contaminated soils. Final report

    International Nuclear Information System (INIS)

    The aqueous biphasic extraction (ABE) process for soil decontamination involves the selective partitioning of solutes and fine particulates between two immiscible aqueous phases. The biphase system is generated by the appropriate combination of a water-soluble polymer (e.g., polyethlene glycol) with an inorganic salt (e.g., sodium carbonate). Selective partitioning results in 99 to 99.5% of the soil being recovered in the cleaned-soil fraction, while only 0.5 to 1% is recovered in the contaminant concentrate. The ABE process is best suited to the recovery of ultrafine, refractory material from the silt and clay fractions of soils. During continuous countercurrent extraction tests with soil samples from the Fernald Environmental Management Project site (Fernald, OH), particulate thorium was extracted and concentrated between 6- and 16-fold, while the uranium concentration was reduced from about 500 mg/kg to about 77 mg/kg. Carbonate leaching alone was able to reduce the uranium concentration only to 146 mg/kg. Preliminary estimates for treatment costs are approximately $160 per ton of dry soil. A detailed flowsheet of the ABE process is provided

  14. Thermodynamics of extraction of plutonium(IV) and americium(III) in polyethylene glycol (PEG) and (NH4)2SO4 based aqueous biphasic system (ABS) using 18-crown-6

    International Nuclear Information System (INIS)

    Extraction of plutonium(IV) and americium(III) using PEG-2000/(NH4)2SO4 (40% w/w of each) aqueous biphasic system (ABS) with 18-crown-6 (18-C-6) was studied at four different temperatures in the range of 288 to 318 K. The species extracted are identified to be [Pu.2(18-C-6)](SO4)2 and [Am.2(18-C-6)](SO4)1.5 for Pu(IV) and Am(III), respectively, by the slope ratio method. The thermodynamic parameters evaluated at 298 K by the temperature coefficient approach show that the reaction is favoured by decrease of enthalpy and counteracted by decrease in entropy in the case of Pu(IV) as well as Am(III). The large decrease in the enthalpy observed indicates that there is direct bonding of crown ether to the central metal atom i.e. the formation of inner sphere complex for both Pu(IV) and Am(III) and is similar to that reported previously for Pu(VI). The order of equilibrium constant K and ΔG value is Pu(IV) > Pu(VI) > Am(III) and this is in accordance with the axial charge experienced by the incoming ligand. (orig.)

  15. Biphasic Catalytic(Hydroformylation of 1-Dodecene in Micellar System with Cationic Gemini Surfactants

    Institute of Scientific and Technical Information of China (English)

    Min LI; Bin XU; Hua CHEN; Hong Jie ZHENG; Xue Yuan HUANG; Yao Zhong LI; Xian Jun LI

    2004-01-01

    The promotion effect of cationic gemini surfactants for the hydroformylation of 1-dodecene in the organic/aqueous biphasic catalytic system is reported. The hydroformylation reaction in the presence of gemini surfactant occurred with higher turnover frequency and higher selectivity for linear aldehyde than using conventional monomeric surfactant CTAB.

  16. Biphasic responses in multi-site phosphorylation systems

    OpenAIRE

    Suwanmajo, Thapanar; Krishnan, J.

    2013-01-01

    Multi-site phosphorylation systems are repeatedly encountered in cellular biology and multi-site modification is a basic building block of post-translational modification. In this paper, we demonstrate how distributive multi-site modification mechanisms by a single kinase/phosphatase pair can lead to biphasic/partial biphasic dose–response characteristics for the maximally phosphorylated substrate at steady state. We use simulations and analysis to uncover a hidden competing effect which is r...

  17. Aqueous biphasic systems with ionic liquids

    OpenAIRE

    Neves, Catarina Maia Seco Seiça

    2009-01-01

    O objectivo principal deste trabalho é estudar o equilíbrio de fases de líquidos iónicos em sistemas aquosos bifásicos. Para isso foram estudadas as solubilidades mútuas entre água e líquidos iónicos hidrofóbicos, e foi criado um modelo que descreve esta propriedade. Além disso, foram realizados e estudados sistemas aquosos bifásicos com líquidos iónicos hidrofílicos e o sal inorgânico K3PO4. Os líquidos iónicos são sais compostos por iões grandes que não formam uma rede cristalina b...

  18. Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

    Science.gov (United States)

    Ng, Choong Hey; Yang, Kun-Lin

    2016-01-01

    Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp. PMID:26672465

  19. Steroid biotransformations in biphasic systems with Yarrowia lipolytica expressing human liver cytochrome P450 genes

    Directory of Open Access Journals (Sweden)

    Braun Andreas

    2012-08-01

    Full Text Available Abstract Background Yarrowia lipolytica efficiently metabolizes and assimilates hydrophobic compounds such as n-alkanes and fatty acids. Efficient substrate uptake is enabled by naturally secreted emulsifiers and a modified cell surface hydrophobicity and protrusions formed by this yeast. We were examining the potential of recombinant Y. lipolytica as a biocatalyst for the oxidation of hardly soluble hydrophobic steroids. Furthermore, two-liquid biphasic culture systems were evaluated to increase substrate availability. While cells, together with water soluble nutrients, are maintained in the aqueous phase, substrates and most of the products are contained in a second water-immiscible organic solvent phase. Results For the first time we have co-expressed the human cytochromes P450 2D6 and 3A4 genes in Y. lipolytica together with human cytochrome P450 reductase (hCPR or Y. lipolytica cytochrome P450 reductase (YlCPR. These whole-cell biocatalysts were used for the conversion of poorly soluble steroids in biphasic systems. Employing a biphasic system with the organic solvent and Y. lipolytica carbon source ethyl oleate for the whole-cell bioconversion of progesterone, the initial specific hydroxylation rate in a 1.5 L stirred tank bioreactor was further increased 2-fold. Furthermore, the product formation was significantly prolonged as compared to the aqueous system. Co-expression of the human CPR gene led to a 4-10-fold higher specific activity, compared to the co-overexpression of the native Y. lipolytica CPR gene. Multicopy transformants showed a 50-70-fold increase of activity as compared to single copy strains. Conclusions Alkane-assimilating yeast Y. lipolytica, coupled with the described expression strategies, demonstrated its high potential for biotransformations of hydrophobic substrates in two-liquid biphasic systems. Especially organic solvents which can be efficiently taken up and/or metabolized by the cell might enable more

  20. Recoverable and recyclable water-soluble sulphonated salicylaldimine Rh(I) complexes for 1-octene hydroformylation in aqueous biphasic media.

    Science.gov (United States)

    Matsinha, Leah C; Mapolie, Selwyn F; Smith, Gregory S

    2015-01-21

    A series of water-soluble Rh(i) mononuclear complexes of general formula: [Rh(sulphsal-X-R)(COD)] [sulphsal = sulphonated salicylaldimine, COD = cyclooctadiene; where R = H, Cl, CH3 and X = H, (t)Bu] have been synthesized. All the compounds were characterised using various spectroscopic and analytical techniques such as nuclear magnetic resonance spectroscopy, infrared spectroscopy, single crystal X-ray diffraction (for complex ) and mass spectrometry. All the compounds display excellent water-solubility at room temperature and were tested as catalyst precursors in the aqueous biphasic hydroformylation of 1-octene. The catalysts could be easily recovered by phase separation and were used up to 5 times without any significant loss in activity and 1-octene conversion. Very high yields of the expected aldehydes were obtained without addition of any phase transfer agents, co-solvents or hydrophobic ligands. Excellent aldehyde chemoselectivity is observed for all the catalysts but this varied each time the catalysts were recycled, with the formation of a small amount of internal olefins. ICP-OES and mercury poisoning experiments show that a combination of homogeneous catalysis and catalysis mediated by nanoparticles is taking place in these systems. PMID:25415263

  1. Superabsorbent biphasic system based on poly(lactic acid) and poly(acrylic acid)

    Science.gov (United States)

    Sartore, Luciana; Pandini, Stefano; Baldi, Francesco; Bignotti, Fabio

    2016-05-01

    In this research work, biocomposites based on crosslinked particles of poly(acrylic acid), commonly used as superabsorbent polymer (SAP), and poly-L-lactic acid (PLLA) were developed to elucidate the role of the filler (i.e., polymeric crosslinked particles) on the overall physico-mechanical behavior and to obtain superabsorbent thermoplastic products. Samples prepared by melt-blending of components in different ratios showed a biphasic system with a regular distribution of particles, with diameter ranging from 5 to 10 μm, within the PLLA polymeric matrix. The polymeric biphasic system, coded PLASA i.e. superabsorbent poly(lactic acid), showed excellent swelling properties, demonstrating that cross-linked particles retain their superabsorbent ability, as in their free counterparts, even if distributed in a thermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidence enhanced thermal stability in comparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles which induce regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from PLLA matrix generating very high porosity. These new open-pore PLLA foams, produced in absence of organic solvents and chemical foaming agents, with good physico-mechanical properties appear very promising for several applications, for instance in tissue engineering for scaffold production.

  2. Aqueous biphasic treatment of some nitrocompounds with hydrogen in the presence of a biogenerated Pd-polysaccharide.

    Science.gov (United States)

    Paganelli, Stefano; Tassini, Riccardo; La Sorella, Giorgio; Piccolo, Oreste; Baldi, Franco; Rathod, Vikas D

    2015-03-25

    A strain of Klebsiella oxytoca BAS-10, known to produce a specific exopolysaccharide (EPS), when grown aerobically in static mode in the presence of Pd(NO3)2, generated the species Pd-EPS that was used as catalyst precursor in the aqueous biphasic treatment of some nitrocompounds with hydrogen. Nitrobenzene was hydrogenated to aniline with almost quantitative yields and the catalyst, embedded in the aqueous phase, was used with success and with near the same efficiency in three recycling experiments. In the case of 1-iodo-4-nitrobenzene only nitrobenzene was obtained while the unsaturated nitro compound β-methyl-β-nitrostyrene afforded both the corresponding oxime and the saturated nitro derivative. PMID:25655572

  3. Biphasic gastroretentive drug delivery system of acyclovir: formulation and in vitro evaluation

    OpenAIRE

    Bandari, Suresh; Yamsani, Madhusudan R.

    2010-01-01

    A biphasic gastroretentive drug delivery system of acyclovir consisted of loading dose tablet and floating multiple matrix tablets was prepared by direct compression process. The delivery system was designed by hydroxy propyl methyl cellulose as retardant polymer with an effervescent component to get the desired buoyant and sustained release characteristics. All formulations compile within the limits. The FTIR studies did not show any evidence of an interaction between acyclovir a...

  4. Enhanced dibenzothiophene biodesulfurization by immobilized cells of Brevibacterium lutescens in n-octane-water biphasic system.

    Science.gov (United States)

    Dai, Yong; Shao, Rong; Qi, Gang; Ding, Bin-Bin

    2014-11-01

    In this study, it was the first report that the Brevibacterium lutescens CCZU12-1 was employed as a sulfur removing bacteria. Using dibenzothiophene (DBT) as the sole sulfur source, B. lutescens could selectively degrade DBT into 2-hydroxybiphenyl (2-HBP) via the "4S" pathway. In the basal salt medium (BSM) supplemented with 0.25 mM DBT and 0.5 g/L Tween-80, high desulfurization rate (100 %) was obtained by growth cells after 60 h. Furthermore, the n-octane-water (10:90, v/v) biphasic system was built for the biodesulfurization by resting cells. Moreover, a combination of magnetic nano Fe3O4 particles with calcium alginate immobilization was used for enhancing biodesulfurization. In this n-octane-water biphasic system, immobilized B. lutescens cells could be reused for not less than four times. Therefore, B. lutescens CCZU12-1 shows high potential in the biodesulfurization. PMID:25173674

  5. Dehydration of xylose to furfural over niobium phosphate catalyst in biphasic solvent system

    Institute of Scientific and Technical Information of China (English)

    Boonrat; Pholjaroen; Ning; Li; Zhiqiang; Wang; Aiqin; Wang; Tao; Zhang

    2013-01-01

    Phosphoric acid treated niobic acid(NbP)was used for the dehydration of xylose to furfural in biphasic solvent system,which was found to exhibit the best performance among the tested catalysts.The excellent performance of NbP could be explained by the better synergistic cooperation between Bro¨nsted and Lewis acid sites.Moreover,NbP showed good stability and no obvious deactivation or leaching of Nb could be observed after six continuous recycles.

  6. Fully Supramolecular Polyrotaxanes as Biphase Drug Delivery Systems

    OpenAIRE

    2014-01-01

    Pseudopolyrotaxanes (PPR) consisting of α-cyclodextrin rings and polyethylene glycol axes with end thymine groups have been synthesized and characterized successfully. Fluorescein (Fl) as a model drug was conjugated to the hydroxyl functional groups of cyclodextrin rings of PPR via ester bonds and PPR-Fl as the primary drug delivery system was obtained. Finally PPR-Fl was capped by hydrogen bonds between end thymine groups and a suitable complementary molecule such as polycitric acid, citric ...

  7. Mars Aqueous Processing System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mars Aqueous Processing System (MAPS) is an innovative method to produce useful building materials from Martian regolith. Acids and bases produced from the regolith...

  8. Mars Aqueous Processing System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mars Aqueous Processing System (MAPS) is a novel technology for recovering oxygen, iron, and other constituents from lunar and Mars soils. The closed-loop...

  9. Glucose dehydration to 5-hydroxymethylfurfural in a biphasic system over solid acid foams.

    Science.gov (United States)

    Ordomsky, Vitaly V; van der Schaaf, John; Schouten, Jaap C; Nijhuis, T Alexander

    2013-09-01

    A solid acid foam-structured catalyst based on a binderless zirconium phosphate (ZrPO) coating on aluminum foam was prepared. The catalyst layer was obtained by performing a multiple washcoating procedure of ZrPO slurry on the anodized aluminum foam. The effect of the pretreatment of ZrPO, the concentration of the slurry, and the amount of coating on the properties of the foam was studied. The catalytic properties of the prepared foams have been evaluated in the dehydration of glucose to 5-hydroxymethylfurfural (HMF) in a biphasic reactor. The catalytic behavior of ZrPO foam-based catalysts was studied in a rotating foam reactor and compared with that of bulk ZrPO. The effect of a silylation procedure on the selectivity of the process was shown over bulk and foam catalysts. This treatment resulted in a higher selectivity due to the deactivation of unselective Lewis acid sites. Addition of methylisobutylketone leads to extraction of HMF from the aqueous phase and stabilization of the selectivity to HMF over bulk ZrPO. A more intensive contact of the foam with the aqueous and organic phases leads to an increase in the selectivity and resistance to deactivation of the foam in comparison with a bulk catalyst. PMID:23616489

  10. Electrochemical assessment of water|ionic liquid biphasic systems towards cesium extraction from nuclear waste

    OpenAIRE

    Stockmann, T. Jane; Zhang, Jing; Montgomery, Anne-Marie; Ding, Zhifeng

    2014-01-01

    A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P66614(+)) and tetrakis(pentafluorophenyl) borate anion (TB) was employed within a water| P66614TB (w|P66614TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. Cs-137 is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is th...

  11. A Novel Ionic Liquid/water Biphasic System for the Preparation of Oximes

    Institute of Scientific and Technical Information of China (English)

    Hui Mou LUO; Yi Qun LI; Wen Jie ZHENG

    2005-01-01

    A variety of carbonyl compounds can be converted into oximes efficiently and conveniently in a novel ionic liquid/water bi-phasic system in the presence of sodium bicarbonate at ambient temperature. The ionic liquid 1-butyl-3-methyl imidazolium hexafluorophosphate [bmim]PF6 is immiscible with water or diethyl ether and can be easily recycled for reuse without noticeable droping in activity after separation of the products. The protocol is rapid, the yields are excellent, the method is simple and the ionic liquid can be reused.

  12. Efficient One-Pot Synthesis of 5-Chloromethylfurfural (CMF from Carbohydrates in Mild Biphasic Systems

    Directory of Open Access Journals (Sweden)

    Dimitris S. Argyropoulos

    2013-07-01

    Full Text Available 5-Halomethylfurfurals can be considered as platform chemicals of high reactivity making them useful for the preparation of a variety of important compounds. In this study, a one-pot route for the conversion of carbohydrates into 5-chloromethylfurfural (CMF in a simple and efficient (HCl-H3PO4/CHCl3 biphasic system has been investigated. Monosaccharides such as D-fructose, D-glucose and sorbose, disaccharides such as sucrose and cellobiose and polysaccharides such as cellulose were successfully converted into CMF in satisfactory yields under mild conditions. Our data shows that when using D-fructose the optimum yield of CMF was about 47%. This understanding allowed us to extent our work to biomaterials, such as wood powder and wood pulps with yields of CMF obtained being comparable to those seen with some of the enumerated mono and disaccharides. Overall, the proposed (HCl-H3PO4/CHCl3 optimized biphasic system provides a simple, mild, and cost-effective means to prepare CMF from renewable resources.

  13. Micrometer-scale mixing with Pickering emulsions: biphasic reactions without stirring.

    Science.gov (United States)

    Zhang, Wenjuan; Fu, Luman; Yang, Hengquan

    2014-02-01

    A general strategy that avoids stirring for organic/aqueous reactions involving solid catalysts is reported. The strategy involves converting a conventional biphasic system into a Pickering emulsion phase with micrometer-scale droplets ensuring good mixing. In test reactions, nitrotoluene reduction and epoxidation of allylic alcohols, the reaction efficiency is comparable to conventional stirrer-driven biphasic catalysis reaction systems. Short diffusion distances, arising from the compartmentalization of densely packed droplets, play an important role in boosting the reaction efficiency. PMID:24376132

  14. Electrochemical assessment of water|ionic liquid biphasic systems towards cesium extraction from nuclear waste

    International Nuclear Information System (INIS)

    Highlights: • Electroanalytical chemistry was employed to assess cesium ion extraction in biphasic systems. • Water|ionic liquid systems are much more efficient than traditional water|organic ones. • The metal ion to ligand stoichiometry and overall complexation constant were determined. • The stoichiometry was confirmed by mass spectrometry. • The ligand CMPO used in TRUEX processes was found to be effective for the FIT. - Abstract: A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P66614+) and tetrakis(pentafluorophenyl)borate anion (TB−) was employed within a water|P66614TB (w|P66614TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. 137Cs is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is therefore of considerable importance. The extraction was facilitated by the ligand octyl(phenyl)-N,N′-diisobutylcarbamoylphosphine oxide (CMPO) used in TRans-Uranium EXtraction processes and investigated through well established liquid|liquid electrochemistry. This study gave access to the metal ion to ligand (1:n) stoichiometry and overall complexation constant, β, of the interfacial complexation reaction which were determined to be 1:3 and 1.6 × 1011 at the w|P66614TB interface while the study at w|o elicited an n equal to 1 with β equal to 86.5. Through a straightforward relationship, these complexation constant values were converted to distribution coefficients, δα, with the ligand concentrations studied for comparison to other studies present in the literature; the w|o and w|IL systems gave δα of 2 and 8.2 × 107, respectively, indicating a higher overall extraction efficiency for the latter. For the w|o system, the metal ion-ligand stoichiometries were confirmed through isotopic distribution analysis of mass spectra obtained by

  15. Electrochemical assessment of water|ionic liquid biphasic systems towards cesium extraction from nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Stockmann, T. Jane [Laboratoire d’Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, Lausanne CH-1015 (Switzerland); Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7 (Canada); Zhang, Jing; Montgomery, Anne-Marie [Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7 (Canada); Ding, Zhifeng, E-mail: zfding@uwo.ca [Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7 (Canada)

    2014-04-01

    Highlights: • Electroanalytical chemistry was employed to assess cesium ion extraction in biphasic systems. • Water|ionic liquid systems are much more efficient than traditional water|organic ones. • The metal ion to ligand stoichiometry and overall complexation constant were determined. • The stoichiometry was confirmed by mass spectrometry. • The ligand CMPO used in TRUEX processes was found to be effective for the FIT. Abstract: A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P66614⁺) and tetrakis(pentafluorophenyl)borate anion (TB⁻) was employed within a water|P66614TB (w|P66614TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. ¹³⁷Cs is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is therefore of considerable importance. The extraction was facilitated by the ligand octyl(phenyl)-N,N'-diisobutylcarbamoylphosphine oxide (CMPO) used in TRans-Uranium EXtraction processes and investigated through well established liquid|liquid electrochemistry. This study gave access to the metal ion to ligand (1:n) stoichiometry and overall complexation constant, β, of the interfacial complexation reaction which were determined to be 1:3 and 1.6 × 10¹¹ at the w|P66614TB interface while the study at w|o elicited an n equal to 1 with β equal to 86.5. Through a straightforward relationship, these complexation constant values were converted to distribution coefficients, δα, with the ligand concentrations studied for comparison to other studies present in the literature; the w|o and w|IL systems gave δα of 2 and 8.2 × 10⁷, respectively, indicating a higher overall extraction efficiency for the latter. For the w|o system, the metal ion-ligand stoichiometries were

  16. Mass transfer studies in miniature Rotating Disc Contactor (RDC) with 30% TBP/nitric acid biphasic system

    International Nuclear Information System (INIS)

    The rotating disc contactor is the widely used liquid-liquid extraction equipment for its high throughput and efficiency. In this work mass transfer performance of the miniature RDC column for the 30% TBP/nitric acid biphasic system was studied in terms of the operating variables such as rotor speed and flow rate of the aqueous and organic phase. The RDC column used in the experiments was shown. The column shell is made up of thick glass having diameter of 10.5 cm and height 100 cm. The rotor diameter is 5.3 cm and stator opening diameter is 6.3 cm. Totally 25 number of rotor discs were welded in the rotating shaft. This shaft was aligned in such a way that each rotor was placed in the centre of the compartment formed in between the two stator rings. The experiments were carried out to study the effect of rotor speed and superficial velocity of the dispersed and continuous phase on mass transfer efficiency. The organic solvent was made as the continuous phase and O/A ratio was set as 4 in both the continuous to dispersed phase(c-d) and dispersed to continuous phase (d-c) mass transfer experiments. The Number of Transfer Units (NTU) was estimated based on the solvent phase. The graphical representation of NTU was shown. The NTU value was observed as 4 and 3 respectively for extraction and stripping at the combined through put of 60 L/h and the rotor speed of 1000 rpm. This corresponds to the Height of Transfer Unit (HTU) value of 15 cm and 20 cm respectively for d-c and c-d mass transfer. The estimated overall mass transfer coefficient was increasing with rotor speed and superficial velocity of the liquid phases. The overall mass transfer coefficient also increases with increase in hold up

  17. Irradiation of Oil / Water Biphasic Systems: the Importance of Interfacial Surface Area on the Production of Hydrogen and Other Deleterious Products

    International Nuclear Information System (INIS)

    -water interfacial surface area, control of headspace gas composition, and removal of sample aliquots. Results highlight the importance of interfacial surface area in affecting the radiolytic degradation of the studied hydrocarbons. In particular, experiments having higher oil-water interfacial surface areas generate greater quantities of oil degradation products as compared with lower surface area samples. As expected, one notable result from these irradiations was the formation of significant quantities of hydrogen, which was found to be dependent on the interfacial surface area. Presented here is a review of the radiolytic degradation of insoluble organic material in aqueous systems, a summary of experimental results focusing on biphasic systems and a description of a strategy to mitigate the effects of insoluble organic material ingress and to aid in developing station-appropriate responses. (authors)

  18. Modeling Diffusion Interaction in the bi-Phase Systems with Using Different Types of the Effective Kinetic Coefficients

    Directory of Open Access Journals (Sweden)

    L.I. Gladka

    2012-10-01

    Full Text Available The analysis of basic and combined models for calculation of effective kinetic coefficients required to describe diffusion processes in two-phase heterogeneous environments is conducted. For a transition zone that grows between two interacting diffusion phases was built a new model of effective medium. In this model the effective kinetic coefficient depends on the kinetic coefficients in each of the phases, volumetric particle phases and additional free parameter, which generally characterizes the type of structure of a bi-phase zone. It is shown that the combined model is constructed to describe the percolation behavior of effective medium. The phenomenological approach describes the formation and development of bi-phase zones in ternary systems which including streams through both phases and the analysis of the impact of the model on the resulting effective medium diffusion zone.

  19. Biotransformation of indole to indigo by the whole cells of phenol hydroxylase engineered strain in biphasic systems.

    Science.gov (United States)

    Shi, Shengnan; Ma, Fang; Sun, Tieheng; Li, Ang; Zhou, Jiti; Qu, Yuanyuan

    2013-02-01

    Biotransformation of indole to indigo in liquid-liquid biphasic systems was performed in Escherichia coli cells expressing phenol hydroxylase. It was suggested that indole could inhibit the cell growth even at low concentration of 0.1 g/L. The critical Log P for strain PH_(IND) was about 5.0. Three different solvents, i.e., decane, dodecane, and dioctyl phthalate, were selected as organic phase in biphasic media. The results showed that dodecane gave the highest yield of indigo (176.4 mg/L), which was more than that of single phase (90.5 mg/L). The optimal conditions for biotransformation evaluated by response surface methodology were as follows: 540.26 mg/L of indole concentration, 42.27 % of organic phase ratio, and 200 r/min of stirrer speed; under these conditions, the maximal production of indigo was 243.51 mg/L. This study proved that the potential application of strain PH_(IND) in the biotransformation of indole to indigo using liquid-liquid biphasic systems. PMID:23306892

  20. Electrochemical assessment of water|ionic liquid biphasic systems towards cesium extraction from nuclear waste.

    Science.gov (United States)

    Stockmann, T Jane; Zhang, Jing; Montgomery, Anne-Marie; Ding, Zhifeng

    2014-04-22

    A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P66614(+)) and tetrakis(pentafluorophenyl)borate anion (TB(-)) was employed within a water|P66614TB (w|P66614TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. (137)Cs is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is therefore of considerable importance. The extraction was facilitated by the ligand octyl(phenyl)-N,N'-diisobutylcarbamoylphosphine oxide (CMPO) used in TRans-Uranium EXtraction processes and investigated through well established liquid|liquid electrochemistry. This study gave access to the metal ion to ligand (1:n) stoichiometry and overall complexation constant, β, of the interfacial complexation reaction which were determined to be 1:3 and 1.6×10(11) at the w|P66614TB interface while the study at w|o elicited an n equal to 1 with β equal to 86.5. Through a straightforward relationship, these complexation constant values were converted to distribution coefficients, δ(α), with the ligand concentrations studied for comparison to other studies present in the literature; the w|o and w|IL systems gave δ(α) of 2 and 8.2×10(7), respectively, indicating a higher overall extraction efficiency for the latter. For the w|o system, the metal ion-ligand stoichiometries were confirmed through isotopic distribution analysis of mass spectra obtained by the direct injection of an emulsified water-organic solvent mixture into an electron spray ionization mass spectrometer. PMID:24703212

  1. Production of levulinic acid, furfural, and gamma valerolactone from C.sub.5 and C.sub.6 carbohydrates in mono- and biphasic systems using gamma-valerolactone as a solvent

    Energy Technology Data Exchange (ETDEWEB)

    Dumesic, James A.; Alonso, David Martin; Gurbuz, Elif I.; Wettstein, Stephanie G.

    2013-03-19

    A method to make levulinic acid (LA), furfural, or gamma-valerolactone (GVL). React cellulose (and/or other C.sub.6 carbohydrates) or xylose (and/or other C.sub.5 carbohydrates) or combinations thereof in a monophasic reaction medium comprising GVL and an acid; or (ii) a biphasic reaction system comprising an organic layer comprising GVL, and a substantially immiscible aqueous layer. At least a portion of the cellulose (and/or other C.sub.6 carbohydrates), if present, is converted to LA and at least a portion of the xylose (and/or other C.sub.5 carbohydrates), if present, is converted into furfural.

  2. Validation of a closed bi-phasic extraction system and of the pancake probe as instruments to radiopharmaceutical quality control procedures

    International Nuclear Information System (INIS)

    Aim: Quality control of radiopharmaceuticals is not a common practice in Nuclear Medicine Services in Brazil. One frequent limitation is that the well counter, used to radioactivity measurement of chromatographic strips, is not available in most services. On the other hand, it's mandatory that all services have a pancake probe to control contaminations. The purpose of this study was to evaluate the accuracy of the quality control (QC) of technetium-99m labeled radiopharmaceuticals using a pancake probe, including chromatography of 99mTc-MDP, 99mTc-DMSA, 99mTc-DMSA-V, 99mTc-Pyp, 99mTc-ECD, 99mTc-Dextran, 99mTc-colloid. Also, we had available a solvent extraction methods using a multi-use closed bi-phasic system to 99mTc-ECD and 99mTc-MIBI, to replace the classical single-use open bi-phasic system. Material and Methods: Classical chromatographic well counter reading and solvent extraction radiochemical controls were used as standards. To variant radiation reading method, pancake probe was covered with a lead disk 3 mm thick, with a 40x10 mm slit; the activity on chromatographic strips (80x10 mm) was read over the slit. The multi-use closed bi-phasic system was done closing the extremities of a 5 or 10 mL glass pipette using flame in the point side, and rubber septa in the other side. The pipette was filled with 2.5 or 3 mL, both organic solvent and aqueous NaCl 0.9 %; then two or three drops of the sample were applied and the tube shook during 30 seconds. Two minutes after, the activity was measured over each phase using the pancake detector. The same solvent mixture was used 3 times, with 48 h interval to allow radioactivity decay. Results: Radiochemical purity determined by the classical or the modified procedures showed Pearson's correlation of 0.973 (n=17) to chromatography; 0.993 to ECD (n=14) extraction and 0.919 to MIBI (n=21) extraction. Conclusion: Our findings suggest that the pancake can be used as a detection instrument in 99mTc-radiopharmaceuticals QC

  3. SOME NOVEL LIQUID PARTITIONING SYSTEMS: WATER-IONIC LIQUIDS AND AQUEOUS BIPHASIC SYSTEMS. (R828257)

    Science.gov (United States)

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

  4. Aqueous systems and geothermal energy

    International Nuclear Information System (INIS)

    Significant unpublished results reported include: osmotic coefficients of KCl solutions vs. molality at 109 to 2010C; cadmium ion diffusivities in CaCl2 hydrous melts; a x-ray diffraction study of the uranyl complex in water; solubility of amorphous silica in aqueous NaNO3 solutions at 100 to 3000C; and corrosion of carbon steel by geothermal brine

  5. Phase equilibrium in systems with ionic liquids: An example for the downstream process of the Biphasic Acid Scavenging utilizing Ionic Liquids (BASIL) process. Part I: Experimental data

    International Nuclear Information System (INIS)

    Highlights: ► Phase equilibrium for a downstream process in sustainable chemical technology. ► Biphasic Acid Scavenging Utilizing Ionic Liquids (BASIL) Process. ► SLE, LLE, and SLLE of (NaCl + water + 1-propanol + 1-MIM) and its ternary subsystems. ► Experimental phase equilibrium data at temperatures between 298 K and 333 K. - Abstract: Experimental results are presented for the (liquid + liquid), (solid + liquid) and (solid + liquid + liquid) equilibria occurring in the downstream process of a typical example for the Biphasic Acid Scavenging Utilizing Ionic Liquids (BASIL)-processes. In a BASIL process an organic base is used to catalyze a chemical reaction and, at the same time, to scavenge an acid that is an undesired side product of that reaction. The particular example of a BASIL process treated here is the reaction of 1-butanol and acetylchloride to butylacetate and hydrochloric acid, where the acid is scavenged by the organic base 1-methyl imidazole (1-MIM) resulting in the ionic liquid 1-methyl imidazolium chloride. The reaction results in a two-phase system as butylacetate and the ionic liquid reveal a large liquid–liquid miscibility gap. The organic base has to be recovered. This is commonly achieved by treating the ionic liquid–rich liquid phase with an aqueous solution of sodium hydroxide (i.e., converting the ionic liquid to the organic base) and extracting the organic base by an appropriate organic solvent (e.g., 1-propanol). The work presented here deals in experimental work with the (liquid + liquid), (solid + liquid) and (solid + liquid + liquid) phase equilibria that are encountered in such extraction processes. Experimental results are reported for temperatures between about 298 K and 333 K: for the solubility of NaCl in several solvents (1-propanol, 1-MIM), (water + 1-MIM), (1-propanol + 1-MIM), (water + 1-propanol), and (water + 1-propanol + 1-MIM) and for the (liquid + liquid) equilibrium as well as for the (solid + liquid

  6. Photoreduction of CO2 Using [Ru(bpy)2(CO)L]n+ Catalysts in Biphasic Solution/Supercritical CO2 Systems

    OpenAIRE

    Voyame, Patrick; Toghill, Kathryn E.; Méndez, Manuel A.; Girault, Hubert H.

    2013-01-01

    The photosensitized reduction of carbon dioxide by the molecular catalyst [Ru(bpy)2(CO)L] is studied in a biphasic liquid-condensed gas system. Increasing pressure is shown to enhance the initial production rate and turnover number of the catalyst before deactivation of the system, especially for formation of carbon monoxide.

  7. Microbial side-chain cleavage of phytosterols by mycobacteria in vegetable oil/aqueous two-phase system.

    Science.gov (United States)

    Xu, Yang-Guang; Guan, Yi-Xin; Wang, Hai-Qing; Yao, Shan-Jing

    2014-09-01

    Microbial side-chain cleavage of natural sterols to 4-androstene-3,17-dione (AD) and 1,4-androstadiene-3,17-dione (ADD) by Mycobacteria has received much attention in pharmaceutical industry, while low yield of the reaction owing to the strong hydrophobicity of sterols is a tough problem to be solved urgently. Eight kinds of vegetable oils, i.e., sunflower, peanut, corn, olive, linseed, walnut, grape seed, and rice oil, were used to construct oil/aqueous biphasic systems in the biotransformation of phytosterols by Mycobacterium sp. MB 3683 cells. The results indicated that vegetable oils are suitable for phytosterol biotransformation. Specially, the yield of AD carried out in sunflower biphasic system (phase ratio of 1:9, oil to aqueous) was greatly increased to 84.8 % with 10 g/L feeding concentration after 120-h transformation at 30 °C and 200 rpm. Distribution coefficients of AD in different oil/aqueous systems were also determined. Because vegetable oils are of low cost and because of their eco-friendly characters, there is a great potential for the application of oil/aqueous two-phase systems in bacteria whole cell biocatalysis. PMID:25082765

  8. Aqueous biphasic system based on cholinium ionic liquids: extraction of biologically active phenolic acids

    OpenAIRE

    Branco, Sónia Isabel Pereira

    2014-01-01

    Phenolic acids are aromatic secondary plant metabolites, widely spread throughout the plant kingdom. Due to their biological and pharmacological properties, they have been playing an important role in phytotherapy and consequently techniques for their separation and purification are in need. This thesis aims at exploring new sustainable separation processes based on ionic liquids (ILs) in the extraction of biologically active phenolic acids. For that purpose, three phenolic acids with simi...

  9. Study of the applicability of non-conventional aqueous two-phase systems in counter-current and centrifugal partition chromatography.

    Science.gov (United States)

    Bezold, Franziska; Goll, Johannes; Minceva, Mirjana

    2015-04-01

    Aqueous two-phase systems composed of imidazolium-based ionic liquids and phosphate salts were evaluated for their applicability in liquid-liquid chromatography. The influence of the nature of ionic liquid anion and cation on the partitioning of bovine serum albumin, lysozyme and myoglobin was investigated. A mixture of K2HPO4 and KH2PO4 in a ratio of 1.82:1 wt/wt was used in all of the tested biphasic systems to adjust the pH to a range of 7-8. The results show that more hydrophobic cations decrease the partition coefficients of the proteins in the biphasic systems and outweigh the effect of the anion on the distribution of the macromolecules. Viscosities and densities of the biphasic systems were in a suitable range for liquid-liquid chromatography. Even though the partition coefficients were too high for a conventional batch operation mode, these aqueous two-phase systems show favorable properties for protein capturing in liquid-liquid chromatographic columns. Additionally, the possible application of ionic liquids as modifiers in polyethylene glycol (PEG)-based aqueous two-phase systems was investigated. It could be demonstrated that ionic liquids alter the partition coefficients of the proteins. PMID:25736304

  10. Magnetite Oxidation in Aqueous Systems

    OpenAIRE

    Templeton, John Andrew

    2008-01-01

    Magnetite, an iron oxide, is a possible candidate for in situ remediation of contaminated groundwater systems due to its oxidation/reduction potential for reduction of contaminants such as carbon tetrachloride. Little characterization and analysis has been done to describe the kinetics of magnetite transformation during oxidation. This work focuses on monitoring the concentrations of magnetite and one of its oxidation transformation products, maghemite, by the use of UV-Vis-NIR spectroscopy...

  11. Hydroformylation in fluorous biphasic media

    OpenAIRE

    Mathison, Clare R.

    2007-01-01

    The hydroformylation of oct-1-ene is investigated under fluorous biphasic conditions, utilising the facile catalyst recovery that is provided by the temperature dependent miscibility of the perfluorinated solvent with normal organic solvents. High conversions and selectivities have been obtained in the batch process and the system is now described under continuous-flow conditions in a custom built reactor. The continuous-flow reactor was successfully run for 46 hours, with conversions to...

  12. Surface chemistry and catalytic properties of VOX/Ti-MCM-41 catalysts for dibenzothiophene oxidation in a biphasic system

    Science.gov (United States)

    González, J.; Chen, L. F.; Wang, J. A.; Manríquez, Ma.; Limas, R.; Schachat, P.; Navarrete, J.; Contreras, J. L.

    2016-08-01

    A series of vanadium oxide supported on Ti-MCM-41 catalysts was synthesized via the incipient impregnation method by varying the vanadia loading from 5 wt% to 10, 15, 20 and 25 wt%. These catalysts were characterized by a variety of advanced techniques for investigating their crystalline structure, textural properties, and surface chemistry information including surface acidity, reducibility, vanadium oxidation states, and morphological features. The catalytic activities of the catalysts were evaluated in a biphasic reaction system for oxidative desulfurization (ODS) of a model diesel containing 300 ppm of dibenzothiophene (DBT) where acetonitrile was used as extraction solvent and H2O2 as oxidant. ODS activity was found to be proportional to the V5+/(V4+ + V5+) values of the catalysts, indicating that the surface vanadium pentoxide (V2O5) was the active phase. Reaction temperature would influence significantly the ODS efficiency; high temperature, i.e., 80 °C, would lead to low ODS reaction due to the partial decomposition of oxidant. All the catalysts contained both Lewis and Brønsted acid sites but the former was predominant. The catalysts with low vanadia loading (5 or 10 wt%V2O5) had many Lewis acid sites and could strongly adsorb DBT molecule via the electron donation/acceptance action which resulted in an inhibition for the reaction of DBT with the surface peroxometallic species. The catalyst with high vanadia loading (25wt%V2O5/Ti-MCM-41) showed the highest catalytic activity and could remove 99.9% of DBT at 60 °C within 60 min.

  13. Use of Saccharomyces cerevisiae yeasts in the chemo selective bioreduction of (1E,4E)-1,5-bis(4-methoxyphenyl)-1,4-pentadien-3-one in biphasic system

    International Nuclear Information System (INIS)

    This work describes the chemoselective bioreduction of (1E,4E)-1,5-bis(4-methoxyphenyl)- 1,4-pentadien-3-one (1) mediated by baker’s yeast (BY, Saccharomyces cerevisiae cells) in an aqueous/organic solvent biphasic system. The biotransformation of this compound was chemoselective and formed only the corresponding saturated ketone 1,5-bis(4-methoxyphenyl)- 3-pentanone (2). The influence of various factors which may alter the bioreduction of 1, such as the type and percentage of co-solvents, use of six different S. cerevisiae yeast samples (four commercial and two industrial), variations in the substrate and yeast concentrations, temperature, pH and volume of aqueous and organic phases, was investigated. The best reaction conditions were 66.7 g L−1 of Fleischmann BY, 8.3 × 10−3 mol L−1 of substrate, pH 6.5 at 35 deg C in the presence of 2.5% (v/v) of N,N-dimethyl sulfoxide (DMSO) as an additive and a Vaq/Vorg ratio of 70/30. Under these conditions, the product 2 was recovered in conversions of 82% in 5 h reaction. (author)

  14. Use of Saccharomyces cerevisiae yeasts in the chemo selective bioreduction of (1E,4E)-1,5-bis(4-methoxyphenyl)-1,4-pentadien-3-one in biphasic system

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Cesar A.; Silva, Vanessa D.; Nascimento, Maria da G., E-mail: maria.nascimento@ufsc.br [Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis-SC (Brazil); Stambuk, Boris U. [Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis-SC (Brazil)

    2013-07-15

    This work describes the chemoselective bioreduction of (1E,4E)-1,5-bis(4-methoxyphenyl)- 1,4-pentadien-3-one (1) mediated by baker's yeast (BY, Saccharomyces cerevisiae cells) in an aqueous/organic solvent biphasic system. The biotransformation of this compound was chemoselective and formed only the corresponding saturated ketone 1,5-bis(4-methoxyphenyl)- 3-pentanone (2). The influence of various factors which may alter the bioreduction of 1, such as the type and percentage of co-solvents, use of six different S. cerevisiae yeast samples (four commercial and two industrial), variations in the substrate and yeast concentrations, temperature, pH and volume of aqueous and organic phases, was investigated. The best reaction conditions were 66.7 g L{sup -1} of Fleischmann BY, 8.3 Multiplication-Sign 10{sup -3} mol L{sup -1} of substrate, pH 6.5 at 35 deg C in the presence of 2.5% (v/v) of N,N-dimethyl sulfoxide (DMSO) as an additive and a V{sub aq}/V{sub org} ratio of 70/30. Under these conditions, the product 2 was recovered in conversions of 82% in 5 h reaction. (author)

  15. A Fluorous Biphasic Solvent Extraction System for Lanthanides with a Fluorophilic β-Diketone Type Extractant.

    Science.gov (United States)

    Nakamura, Etsuko; Hiruta, Yuki; Watanabe, Takafumi; Iwasawa, Naoko; Citterio, Daniel; Suzuki, Koji

    2015-01-01

    The properties of a fluorous solvent extraction system for trivalent lanthanide metal ions are reported. A fluorinated extractant, 4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluoro-1-(2-thienyl)-1,3-nonanedione, and HFE-7200 (C4F9OC2H5) as the extraction solvent were chosen. With this fluorous extractant/solvent combination, higher extraction ratios and separation factors compared to a conventional organic solvent system (thenoyltrifluoroacetone in CHCl3) were achieved for 5 heavy lanthanide ions (Lu, Yb, Tm, Er and Ho). On the other hand, light lanthanide ions (Nd, Pr, Ce and La) are hardly extracted, therefore enabling the mutual separation of light lanthanides from middle or heavy lanthanide ions. PMID:26353959

  16. OPTIMIZATION OF PRODUCTION OF 5-HYDROXYMETHYLFURFURAL FROM GLUCOSE IN A WATER: ACETONE BIPHASIC SYSTEM

    Directory of Open Access Journals (Sweden)

    A. D. M. Mendonça

    2015-06-01

    Full Text Available Abstract5-Hydroxymethylfurfural (HMF is considered to be an important building block for biorefineries and has a high potential for the production of chemicals and fuels. Production of HMF from glucose was studied using phosphoric acid as catalyst, in a water:acetone system with volume ratio of 1:2 and NaCl. An experimental design was applied to examine the influence of temperature, time and concentration of catalyst on the HMF yield. HMF yields of more than 50 % were obtained when using 200 ºC, 8.4 min and 0.8% of catalyst. The temperature is the main factor influencing the HMF yield.

  17. DEVELOPMENT OF BIPHASIC PULSATILE RELEASE MINI-TABLETS SYSTEM OF POORLY WATER SOLUBLE CARVEDILOL PHOSPHATE

    Directory of Open Access Journals (Sweden)

    D. K. Singh

    2015-05-01

    Full Text Available Objective: Carvedilol Phosphate is indicated for the treatment of mild-to-severe chronic heart failure of ischemic or cardiomyopathic origin. The ultimate goal of pulsatile release mini-tablets to deliver a drug to the specific site and then to maintain the desired plasma drug concentration at particular site in chronotherapeutic manner. Among solids, multiparticulate delivery have its own advantages. Pulsatile drug delivery system provides better therapy with many of the actives. Rupturable pulsatile mini-tablet consists of a drug core; swelling layer of a super disintegrant; an insoluble, water-permeable polymeric and enteric coating. Upon water access, the swellable layer expands, resulting in the rupturing of outer membrane followed by drug release. There were no drug release ob served in acid phase. The active pharmaceutical ingredient selected was Carvedilol Phosphate, in core mini-tablets. The second layer composed of swelling excipient, had crospovidone, Croscarmellose sodium and sodium starch glycolate. Third and the outer most layer was based on ethyl cellulose and enteric polymer. The release after lag time was fast and complete, when crospovidone was used as a swelling agent. In contrast, a sustained release was achieved after the lag time, when croscarmellose sodium and sodium starch glycolate were used as swelling agents. Fast release would be preferable in the present case. Optimal level of crospovidone to achieve a fast and complete release of Carvedilol phosphate was 30%. Outer membrane, formed using ethyl cellulose was suitable enough to rupture sufficiently ensuring fast drug release in upper portion of small intestine. It was possible to design multiparticulate of carvedilol phosphate having a suitable release profile.

  18. Advanced Aqueous Separation Systems for Actinide Partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Ken [Washington State Univ., Pullman, WA (United States); Martin, Leigh [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lumetta, Gregg [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-02

    One of the most challenging aspects of advanced processing of used nuclear fuel is the separation of transplutonium actinides from fission product lanthanides. This separation is essential if actinide transmutation options are to be pursued in advanced fuel cycles, as lanthanides compete with actinides for neutrons in both thermal and fast reactors, thus limiting efficiency. The separation is difficult because the chemistry of Am3+ and Cm3+ is nearly identical to that of the trivalent lanthanides (Ln3+). The prior literature teaches that two approaches offer the greatest probability of devising a successful group separation process based on aqueous processes: 1) the application of complexing agents containing ligand donor atoms that are softer than oxygen (N, S, Cl-) or 2) changing the oxidation state of Am to the IV, V, or VI state to increase the essential differences between Am and lanthanide chemistry (an approach utilized in the PUREX process to selectively remove Pu4+ and UO22+ from fission products). The latter approach offers the additional benefit of enabling a separation of Am from Cm, as Cm(III) is resistant to oxidation and so can easily be made to follow the lanthanides. The fundamental limitations of these approaches are that 1) the soft(er) donor atoms that interact more strongly with actinide cations than lanthanides form substantially weaker bonds than oxygen atoms, thus necessitating modification of extraction conditions for adequate phase transfer efficiency, 2) soft donor reagents have been seen to suffer slow phase transfer kinetics and hydro-/radiolytic stability limitations and 3) the upper oxidation states of Am are all moderately strong oxidants, hence of only transient stability in media representative of conventional aqueous separations systems. There are examples in the literature of both approaches having been described. However, it is not clear at present that any extant process is sufficiently robust for application at the scale

  19. Biphasic mini-reactor for characterization of biocatalyst performance

    OpenAIRE

    Van Den Wittenboer, Anne; Schmidt, Thomas; Müller, Pia; Ansorge-Schumacher, Marion Bettina; Greiner, Lasse

    2009-01-01

    Abstract Biphasic reaction media are extending the scope of technical biocatalysis. Thorough investigation of the factors affecting catalyst performance under these conditions is of key importance for the successful implementation of catalytic processes. Here, we present a reactor setup suitable for comprehensive systematic characterization and optimization of biocatalyzed reactions in biphasic systems with distinct phases. It is distinguished by small volumes allowing reproducible...

  20. Oscillatory Motion of a Bi-Phasic Slug in a Teflon Reactor

    Science.gov (United States)

    Abolhasani, Milad; Jensen, Klavs

    2015-11-01

    Bi-phasic physical/chemical processes require transfer of solute/reagent molecules across the interface. Continuous multi-phase flow approaches (using gas as the continuous phase), usually fail in providing sufficient interfacial area for transfer of molecules between the aqueous and organic phases. In continuous segmented flow platforms (with a fluorinated polymer-based reactor), the higher surface tension of the aqueous phase compared to the organic phase of a bi-phasic slug, in combination with the low surface energy of the reactor wall result in a more facile motion of the aqueous phase. Thus, upon applying a pressure gradient across the bi-phasic slug, the aqueous phase of the slug moves through the organic phase and leads the bi-phasic slug, thereby limiting the available interfacial area for the bi-phasic mass transfer only to the semi-spherical interface between the two phases. Disrupting the quasi-equilibrium state of the bi-phasic slug through reversing the pressure gradient across the bi-phasic slug causes the aqueous phase to move back through the organic phase. In this work, we experimentally investigate the dynamics of periodic alteration of the pressure gradient across a bi-phasic slug, and characterize the resulting enhanced interfacial area on the bi-phasic mass transfer rate. We demonstrate the enhanced mass transfer rate of the oscillatory flow strategy compared to the continuous multi-phase approach using bi-phasic Pd catalyzed carbon-carbon and carbon-nitrogen cross coupling reactions. NSERC Postdoctoral Fellowship, Novartis Center for Continuous Manufacturing.

  1. Extraction of plutonium(VI) in polyethylene glycol (PEG) based aqueous biphasic system (ABS) using 18-crown-6

    International Nuclear Information System (INIS)

    Extraction of plutonyl ion was studied using PEG-2000/(NH4)2SO4 (40% w/w of each) ABS with 18-C-6 as the extractant. The species extracted was found to be (PuO2.18-C-6)SO4. The thermodynamic parameters evaluated showed the reaction to be stabilized by lowering of enthalpy and opposed by decrease in entropy. The large decrease in the enthalpy indicates that crown ether is most likely directly bonded to central metal atom (i.e. inner sphere complex) and not through hydrogen bonding. The effect of quenching during counting and sulphate complexing not considered previously are also discussed. (author). 4 refs., 2 figs

  2. Radiation protection of vitamins in aqueous systems

    International Nuclear Information System (INIS)

    A study of the radiation induced decomposition of the B-group vitamins has been carried out in aqueous media at room temperature as well as in rigid matrices at low temperature. The detailed results on the effect of glucose and oxygen as protective additives at the different temperatures are presented in the case of Thiamine (Vitamin B1). Comparative data are given on the extent of decomposition of this and other vitamins of the B-group at room temperature and at 193 K. The importance of these results in connection with the radiation sterilization of pharmaceutical preparations is indicated. (author)

  3. Electrostatic interactions and aqueous two-phase separation modes of aqueous mixed oppositely charged surfactants system.

    Science.gov (United States)

    Hao, Li-Sheng; Gui, Yuan-Xiang; Chen, Yan-Mei; He, Shao-Qing; Nan, Yan-Qing; You, Yi-Lan

    2012-08-30

    Electrostatic interactions play an important role in setting the aqueous two-phase separation behaviors of mixtures of oppositely charged surfactants. The aqueous mixture of cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfonate (AS) is actually a five-component system, comprised of CTAB, AS, complex salt (cetyltrimethylammonium dodecylsulfonate, abbreviated as CTA(+)AS(-)), NaBr, and water. In the three-dimensional pyramid phase diagram, the aqueous two-phase region with excess AS or with excess CTAB extends successively from the region very near to the NaBr-H2O line through the CTAB-AS-H2O conventional mixing plane to the CTA(+)AS(-)-AS-H2O side plane or to the CTA(+)AS(-)-CTAB-H2O side plane, respectively. Large or small molar ratios between the counterions and their corresponding surfactant ions for oppositely charged surfactants located in the NaBr side or the CTA(+)AS(-) side of the pyramid imply strong or weak electrostatic screening. Electrostatic screening of counterions alters the electrostatic attractions between the oppositely charged head groups or the electrostatic repulsions between the like-charged head groups in excess, and the electrostatic free energy of aggregation thus affects the aqueous two-phase separation modes. Composition analysis, rheological property investigation, and TEM images suggest that there are two kinds of aqueous two-phase systems (ATPSs). On the basis of these experimental results and Kaler's cell model, two kinds of phase separation modes were proposed. Experimental results also indicate that all of the top phases are surfactant-rich, and all of the bottom phases are surfactant-poor; the density difference between the top phase and the bottom phase in one ATPS is very small; the interfacial tension (σ) of the ATPS is ultralow. PMID:22856887

  4. Protons and Hydroxide Ions in Aqueous Systems.

    Science.gov (United States)

    Agmon, Noam; Bakker, Huib J; Campen, R Kramer; Henchman, Richard H; Pohl, Peter; Roke, Sylvie; Thämer, Martin; Hassanali, Ali

    2016-07-13

    Understanding the structure and dynamics of water's constituent ions, proton and hydroxide, has been a subject of numerous experimental and theoretical studies over the last century. Besides their obvious importance in acid-base chemistry, these ions play an important role in numerous applications ranging from enzyme catalysis to environmental chemistry. Despite a long history of research, many fundamental issues regarding their properties continue to be an active area of research. Here, we provide a review of the experimental and theoretical advances made in the last several decades in understanding the structure, dynamics, and transport of the proton and hydroxide ions in different aqueous environments, ranging from water clusters to the bulk liquid and its interfaces with hydrophobic surfaces. The propensity of these ions to accumulate at hydrophobic surfaces has been a subject of intense debate, and we highlight the open issues and challenges in this area. Biological applications reviewed include proton transport along the hydration layer of various membranes and through channel proteins, problems that are at the core of cellular bioenergetics. PMID:27314430

  5. Isotope effect of potassium in an aqueous/amalgam system

    International Nuclear Information System (INIS)

    The isotope fractionation of potassium in an aqueous (KOH)/amalgam system has been studied. Two types of isotope effects with opposite isotope enrichment directions were observed in the electrolysis of potassium from the aqueous into the amalgam phase under constant electrolytic potentials. It was found that the first isotope effect causing the light isotope enriched in the amalgam is related to the kinetic process of the mass transfer through the aqueous/amalgam interface, while the second one leading to the enrichment of the heavy isotope in the amalgam phase is produced by the isotope-exchange equilibrium. The temperature dependence of the equilibrium isotope effect was also investigated using single-stage and multi-stage techniques. It was observed that the equilibrium isotope effect increases as the temperature increases in the range of 293-371 K. An empirical equation was used to fit the variations of the isotope effects with temperature for potassium together with the other alkaline and alkaline earth metals studied in the same system. The origin of the equilibrium isotope fractionation in the electron-exchange system was discussed. Furthermore, the mass dependence of the separation coefficients of the alkaline and alkaline earth metals observed in aqueous/amalgam and ion-exchange systems were compared. At 293 K the equilibrium isotope separation coefficient for the 39K/41K isotopes in the amalgam system was determined as (5.6 ± 0.6).10-3. (author)

  6. CONTROLLING THE AQUEOUS MISCIBILITY OF IONIC LIQUIDS: A NOVEL AQUEOUS BIPHASIC SYSTEM FROM WATER-MISCIBLE IONIC LIQUID AND A WATER-STRUCTURING SALT. (R828257)

    Science.gov (United States)

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

  7. Sonolytic and Silent Polymerization of Methacrlyic Acid Butyl Ester Catalyzed by a New Onium Salt with bis-Active Sites in a Biphasic System — A Comparative Investigation

    Directory of Open Access Journals (Sweden)

    Perumberkandgai A. Vivekanand

    2013-02-01

    Full Text Available Currently, ingenious new analytical and process experimental techniques which are environmentally benign techniques, viz., ultrasound irradiation, have become immensely popular in promoting various reactions. In this work, a novel soluble multi-site phase transfer catalyst (PTC viz., 1,4-bis-(propylmethyleneammounium chloridebenzene (BPMACB was synthesized and its catalytic efficiency was assessed by observing the kinetics of sonolytic polymerization of methacrylic acid butyl ester (MABE using potassium persulphate (PPS as an initiator. The ultrasound–multi-site phase transfer catalysis (US-MPTC-assisted polymerization reaction was compared with the silent (non-ultrasonic polymerization reaction. The effects of the catalyst and various reaction parameters on the catalytic performance were in detail investigated by following the kinetics of polymerization of MABE in an ethyl acetate-water biphasic system. From the detailed kinetic investigation we propose a plausible mechanism. Further the kinetic results demonstrate clearly that ultrasound-assisted phase-transfer catalysis significantly increased the reaction rate when compared to silent reactions. Notably, this environmentally benign and cost-effective process has great potential to be applied in various polymer industries.

  8. Fluorous Biphase System of C9F18 and Its Use in Esterification%全氟壬烯氟两相体系及其在酯化反应中的应用

    Institute of Scientific and Technical Information of China (English)

    史鸿鑫; 项菊萍; 武宏科

    2007-01-01

    Some apolar organic solvents is miscible with perfluorous nonene to form fluorous biphase systems.Perfluorous nonene could be used as a green solvent in equimolar esterification of carboxylic acids with alcohols without removal of water or ester formed. Perfluorous nonene made the esterification equilibrium to move right and the yields of esterification to enhance in different degrees as compared with that in the absence of perfiuorous nonene. After esterification perfluorous nonene is easy to be recovered and recycled.

  9. Obtaining of ceramics biphasic dense and porous

    International Nuclear Information System (INIS)

    Among the bioceramic hydroxyapatite (HAP) and beta-tricalcium phosphate (beta-TCP) are materials commonly used in biomedical field. Their combined properties result in a material with absorbable and at the same time with bioactive surface. Called biphasic ceramics such materials respond more quickly when exposed to physiological environment. In this work, powders of HAP/beta-TCP were obtained by chemical precipitation. After obtaining the post-phase was added at a ratio of 0, 15% and 30w% aqueous solutions of corn starch in order to obtain porous bodies. After mixing the resulting solutions were dried, resigned in tablet form and sintered at 1300 deg C. The initial powder was characterized by X-ray diffraction with Rietveld refinement to quantify the phases present. Bodies-of-evidence has been characterized by calculating the bulk density, X-ray diffraction (XRD), scanning electron microscopy and diametral compression. (author)

  10. Acute Biphasic Effects of Ayahuasca.

    Science.gov (United States)

    Schenberg, Eduardo Ekman; Alexandre, João Felipe Morel; Filev, Renato; Cravo, Andre Mascioli; Sato, João Ricardo; Muthukumaraswamy, Suresh D; Yonamine, Maurício; Waguespack, Marian; Lomnicka, Izabela; Barker, Steven A; da Silveira, Dartiu Xavier

    2015-01-01

    Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca's chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered. PMID:26421727

  11. Acute Biphasic Effects of Ayahuasca.

    Directory of Open Access Journals (Sweden)

    Eduardo Ekman Schenberg

    Full Text Available Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca's chemical compounds, mostly N,N-dimethyltryptamine (DMT, harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.

  12. DESIGN OF ROBOTIC COLONIZER CONTROL SYSTEM FOR AQUEOUS ENVIRONMENT

    OpenAIRE

    C Venkatesh; C.CHANDRA SEKHAR

    2013-01-01

    Now a days there is a huge interest on underwater communication systems for various applications in order to explore aqueous environments. Intelligent robots and cooperative multi- agent robotic systems can be very efficient tools to speed up search and research operations in remote areas. Robots are also useful to do jobs inareas and in situations that are hazardous for human, they can go anywhere that is not reachable my humans and can go into gaps and move trough small holes that are impos...

  13. Advanced Aqueous Separation Systems for Actinide Partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Kenneth L.; Clark, Sue; Meier, G Patrick; Alexandratos, Spiro; Paine, Robert; Hancock, Robert; Ensor, Dale

    2012-03-21

    One of the most challenging aspects of advanced processing of spent nuclear fuel is the need to isolate transuranium elements from fission product lanthanides. This project expanded the scope of earlier investigations of americium (Am) partitioning from the lanthanides with the synthesis of new separations materials and a centralized focus on radiochemical characterization of the separation systems that could be developed based on these new materials. The primary objective of this program was to explore alternative materials for actinide separations and to link the design of new reagents for actinide separations to characterizations based on actinide chemistry. In the predominant trivalent oxidation state, the chemistry of lanthanides overlaps substantially with that of the trivalent actinides and their mutual separation is quite challenging.

  14. Design and evaluation of a specific, bi-phase extended release system based on differently coated mini-tablets.

    Science.gov (United States)

    Aleksovski, Aleksandar; Luštrik, Matevž; Šibanc, Rok; Dreu, Rok

    2015-07-30

    Mini-tablets are gaining great attention as systems capable of being formulated into multiple unit systems providing a specific drug release pattern. Within the presented research a combined, multiple-unit system, based on different coated matrix mini-tablets, has been developed in order to achieve 24-h specific sigmoid extended release of the model drug paliperidone. The mini-tablets were based on different amounts of polyvinyl acetate/polyvinyl pyrolidone mixture as the matrix former, providing extended release, and two different types of pH-dependent, acrylic polymer coatings, providing delay in release onset, and thus achieving the required specific sigmoid release pattern imposed by the original drug on the market. The selected formulation proved to be consistent with pharmacopoeial requirements. It was also in vitro similar (f2) to the original drug and the theoretical linear release profile, as well as robust and reproducible regarding in vitro release in different fasted gastro-intestinal conditions. This is proof of concept that 24-h, specific, and almost linear release profile of drugs with high solubility can be achieved by employing technology of coated matrix mini-tablets. PMID:25845632

  15. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

    KAUST Repository

    Akbulut, Ozge

    2012-08-08

    This paper demonstrates the use of aqueous multiphase systems (MuPSs) as media for rate-zonal centrifugation to separate nanoparticles of different shapes and sizes. The properties of MuPSs do not change with time or during centrifugation; this stability facilitates sample collection after separation. A three-phase system demonstrates the separation of the reaction products (nanorods, nanospheres, and large particles) of a synthesis of gold nanorods, and enriches the nanorods from 48 to 99% in less than ten minutes using a benchtop centrifuge. © 2012 American Chemical Society.

  16. Biphasic Catalysis with Disaccharide Phosphorylases: Chemoenzymatic Synthesis of alpha-D-Glucosides Using Sucrose Phosphorylase

    Czech Academy of Sciences Publication Activity Database

    De Winter, K.; Desmet, T.; Devlamynck, T.; Van Renterghem, L.; Verhaeghe, T.; Pelantová, Helena; Křen, Vladimír; Soetaert, W.

    2014-01-01

    Roč. 18, č. 6 (2014), s. 781-787. ISSN 1083-6160 R&D Projects: GA MŠk(CZ) 7E11011 Institutional support: RVO:61388971 Keywords : biphasic systems * pyrogallol * biphasic catalysis Subject RIV: CE - Biochemistry Impact factor: 2.528, year: 2014

  17. Partitioning of glycomacropeptide in aqueous two-phase systems

    OpenAIRE

    Silva, C. A. S.; Coimbra, Jane Sélia dos Reis; Rojas, Edwin Elard Garcia; Teixeira, J. A.

    2009-01-01

    The partition behavior of glycomacropeptide (GMP) was determined in polyethylene glycol (PEG) and sodium citrate aqueous two-phase systems (ATPS). It was found that the partitioning of GMP depends on PEG molar mass, tie line length, pH, NaCl concentration and temperature. The obtained data indicates that GMP is preferentially partitioned into the PEG phase without addition of NaCl at pH 8.0. Larger tie line lengths and higher temperatures favor GMP partition to the PEG phase. Furt...

  18. Analysis of Direct Samples of Early Solar System Aqueous Fluids

    Science.gov (United States)

    Zolensky, Michael E.; Bodnar, R J.; Fedele, L.; Yurimoto,H.; Itoh, S.; Fries, M.; Steele, A.

    2012-01-01

    Over the past three decades we have become increasingly aware of the fundamental importance of water, and aqueous alteration, on primitive solar-system bodies. Some carbonaceous and ordinary chondrites have been altered by interactions with liquid water within the first 10 million years after formation of their parent asteroids. Millimeter to centimeter-sized aggregates of purple halite containing aqueous fluid inclusions were found in the matrix of two freshly-fallen brecciated H chondrite falls, Monahans (1998, hereafter simply "Monahans") (H5) and Zag (H3-6) (Zolensky et al., 1999; Whitby et al., 2000; Bogard et al., 2001) In order to understand origin and evolution of the aqueous fluids inside these inclusions we much measure the actual fluid composition, and also learn the O and H isotopic composition of the water. It has taken a decade for laboratory analytical techniques to catch up to these particular nanomole-sized aqueous samples. We have recently been successful in (1) measuring the isotopic composition of H and O in the water in a few fluid inclusions from the Zag and Monahans halite, (2) mineralogical characterization of the solid mineral phases associated with the aqueous fluids within the halite, and (3) the first minor element analyses of the fluid itself. A Cameca ims-1270 equipped with a cryo-sample-stage of Hokkaido University was specially prepared for the O and H isotopic measurements. The cryo-sample-stage (Techno. I. S. Corp.) was cooled down to c.a. -190 C using liquid nitrogen at which the aqueous fluid in inclusions was frozen. We excavated the salt crystal surfaces to expose the frozen fluids using a 15 keV Cs+ beam and measured negative secondary ions. The secondary ions from deep craters of approximately 10 m in depth emitted stably but the intensities changed gradually during measurement cycles because of shifting states of charge compensation, resulting in rather poor reproducibility of multiple measurements of standard fluid

  19. DOE workshop: Sedimentary systems, aqueous and organic geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    A DOE workshop on sedimentary systems, aqueous and organic geochemistry was held July 15-16, 1993 at Lawrence Berkeley Laboratory. Papers were organized into several sections: Fundamental Properties, containing papers on the thermodynamics of brines, minerals and aqueous electrolyte solutions; Geochemical Transport, covering 3-D imaging of drill core samples, hydrothermal geochemistry, chemical interactions in hydrocarbon reservoirs, fluid flow model application, among others; Rock-Water Interactions, with presentations on stable isotope systematics of fluid/rock interaction, fluid flow and petotectonic evolution, grain boundary transport, sulfur incorporation, tracers in geologic reservoirs, geothermal controls on oil-reservoir evolution, and mineral hydrolysis kinetics; Organic Geochemistry covered new methods for constraining time of hydrocarbon migration, kinetic models of petroleum formation, mudstones in burial diagenesis, compound-specific carbon isotope analysis of petroleums, stability of natural gas, sulfur in sedimentary organic matter, organic geochemistry of deep ocean sediments, direct speciation of metal by optical spectroscopies; and lastly, Sedimentary Systems, covering sequence stratigraphy, seismic reflectors and diagenetic changes in carbonates, geochemistry and origin of regional dolomites, and evidence of large comet or asteroid impacts at extinction boundaries.

  20. Photolysis of difloxacin and sarafloxacin in aqueous systems.

    Science.gov (United States)

    Prabhakaran, Deivasigamani; Sukul, Premasis; Lamshöft, Marc; Maheswari, Mohan Akhila; Zühlke, Sebastian; Spiteller, Michael

    2009-10-01

    The photodegradation of two fluoroquinolone veterinary antibiotics, difloxacin (DIF) and sarafloxacin (SARA) has been explored for the first time in aqueous systems. The study was performed to evaluate the influence of pH, inorganics, humic substances, and other additives. The drugs followed first-order degradation kinetics in matrix free aqueous medium with a rate constant 'k' value of 0.82 and 0.26 h(-1) for DIF and SARA, respectively. Studies performed at various pH revealed that the photolysis rates dropped sharply at pH >7 for DIF, while SARA dissipated faster with increasing pH. Humic substances acted as light barriers by attenuating the light intensity, to retard the drug degradation process. However, rapid drug dissipation was observed in the presence of additives like acetone, hydrogen peroxide, and phosphates, while inorganics such as fluoride, nitrate, and sulfate did not influence the drug photodegradation. Studies on the photolysis of DIF and SARA in river water revealed that both the drugs degraded rapidly under conditions that were relevant to natural systems, following direct photolysis mechanism. It was observed that SARA was the primary photoproduct of DIF and showed relatively a higher persistence than DIF. The findings were also substantiated by the quantum yield (Phi(c)) calculations. The analytical measurements were carried out with LC-MS/MS. PMID:19751946

  1. DOE workshop: Sedimentary systems, aqueous and organic geochemistry

    International Nuclear Information System (INIS)

    A DOE workshop on sedimentary systems, aqueous and organic geochemistry was held July 15-16, 1993 at Lawrence Berkeley Laboratory. Papers were organized into several sections: Fundamental Properties, containing papers on the thermodynamics of brines, minerals and aqueous electrolyte solutions; Geochemical Transport, covering 3-D imaging of drill core samples, hydrothermal geochemistry, chemical interactions in hydrocarbon reservoirs, fluid flow model application, among others; Rock-Water Interactions, with presentations on stable isotope systematics of fluid/rock interaction, fluid flow and petotectonic evolution, grain boundary transport, sulfur incorporation, tracers in geologic reservoirs, geothermal controls on oil-reservoir evolution, and mineral hydrolysis kinetics; Organic Geochemistry covered new methods for constraining time of hydrocarbon migration, kinetic models of petroleum formation, mudstones in burial diagenesis, compound-specific carbon isotope analysis of petroleums, stability of natural gas, sulfur in sedimentary organic matter, organic geochemistry of deep ocean sediments, direct speciation of metal by optical spectroscopies; and lastly, Sedimentary Systems, covering sequence stratigraphy, seismic reflectors and diagenetic changes in carbonates, geochemistry and origin of regional dolomites, and evidence of large comet or asteroid impacts at extinction boundaries

  2. Aqueous two-phase system based on natural quaternary ammonium compounds for the extraction of proteins.

    Science.gov (United States)

    Zeng, Chao-Xi; Xin, Rui-Pu; Qi, Sui-Jian; Yang, Bo; Wang, Yong-Hua

    2016-02-01

    Aqueous two-phase systems, based on the use of natural quaternary ammonium compounds, were developed to establish a benign biotechnological route for efficient protein separation. In this study, aqueous two-phase systems of two natural resources betaine and choline with polyethyleneglycol (PEG400/600) or inorganic salts (K2 HPO4 /K3 PO4 ) were formed. It was shown that in the K2 HPO4 -containing aqueous two-phase system, hydrophobic interactions were an important driving force of protein partitioning, while protein size played a vital role in aqueous two-phase systems that contained polyethylene glycol. An extraction efficiency of more than 90% for bovine serum albumin in the betaine/K2 HPO4 aqueous two-phase system can be obtained, and this betaine-based aqueous two-phase system provided a gentle and stable environment for the protein. In addition, after investigation of the cluster phenomenon in the betaine/K2 HPO4 aqueous two-phase systems, it was suggested that this phenomenon also played a significant role for protein extraction in this system. The development of aqueous two-phase systems based on natural quaternary ammonium compounds not only provided an effective and greener method of aqueous two-phase system to meet the requirements of green chemistry but also may help to solve the mystery of the compartmentalization of biomolecules in cells. PMID:26447826

  3. Partition of proteins in aqueous two-phase systems based on Cashew-nut tree gum and poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    Leonie Asfora Sarubbo

    2004-09-01

    Full Text Available The partitioning of two proteins, bovine serum albumin (BSA and trypsin was studied in an aqueous poly(ethylene glycol(PEG- Cashew-nut tree gum system. The phase diagram was provided for Cashew-nut tree gum and PEG molecular weight of 1500 at two different temperatures. The influence of several parameters including concentrations of polymers, pH, salt addition and temperature on the partitioning of these proteins were investigated.. The results of this research demonstrated the importance of the protein characteristics for partitioning in aqueous biphasic system.A partição de duas proteínas, albumina de soro bovino (BSA e tripsina foi estudada no sistema bifásico aquoso Polietileno glicol(PEG - Goma do cajueiro. O diagrama de fases foi estabelecido para a Goma do Cajueiro e para PEG de peso molecular 1500 em duas diferentes temperaturas. A influência de vários parâmetros na partição destas proteínas, incluindo concentração dos polímeros, pH, adição de sal e temperatura foi investigada. Os resultados desta pesquisa demonstraram a importância das características da proteína na partição em sistemas bifásicos aquosos.

  4. Adsorption of phenol from aqueous systems onto spent oil shale

    Energy Technology Data Exchange (ETDEWEB)

    Darwish, N.A.; Halhouli, K.A.; Al-Dhoon, N.M. [Jordan Univ. of Science and Technology, Irbid (Jordan)

    1996-03-01

    To evaluate its ability to remove phenol from aqueous solution, Jordanian {open_quotes}spent{close_quotes} oil shale, an abundant natural resource, has been used in an experimental adsorption study. Equilibrium of the system has been determined at three temperatures: 30, 40, and 55{degrees}C. The resulting experimental equilibrium isotherms are well represented by Frendlich, Langmuir, and Redlich-Peterson isotherms. The relevant parameters for these isotherms, as regressed from the experimental equilibrium data, are presented. Effects of solution pH (in the range of 3-11), in addition to effects of three inorganic salts (Kl, KCl, and NaCl), on the equilibrium isotherms were also investigated. The effects of pH in the presence of KI and NaCl were also investigated for a possible interaction between salts and solution pH. The initial concentration of phenol in the aqueous system studied ranges from 10 to 200 ppm. Experimental results show that while an acidic solution has no effect on the adsorption capacity of spent oil shale to phenol, a highly basic solution reduces its adsorbability. No sound effect was observed for the inorganic salts studied on the adsorption of phenol on spent oil shale. The experimental results show that there is no interaction between the pH of solution and the presence of salts. In spite of its ability to remove phenol, spent oil shale showed a very low equilibrium capacity (of an order of magnitude of 1 mg/g). Should the adsorption capacity of the shale be improved (by different treatment processes, such as grafting, surface conditioning), results of this study will find a direct practical implication in serving as {open_quotes}raw{close_quotes} reference data for comparison purposes.

  5. Radiation-Engineered Functional Nanoparticles in Aqueous Systems.

    Science.gov (United States)

    Dispenza, Clelia; Grimaldi, Natascia; Sabatino, Maria Antonietta; Soroka, Inna L; Jonsson, Mats

    2015-05-01

    Controlled synthesis of nanoscalar and nanostructured materials enables the development of novel functional materials with fine-tuned optical, mechanical, electronic, magnetic, conductive and catalytic properties that are of use in numerous applications. These materials have also found their potential use in medicine as vehicles for drug delivery, in diagnostics or in combinations thereof. In principle, nanoparticles can be divided into two broad categories, organic and inorganic nanoparticles. For both types of nanoparticles there are numerous possible synthetic routes. Considering the large difference in nature of these materials and the elementary reactions involved in the synthetic routes, most manufacturing techniques are complex and only suitable for one type of particle. Interestingly, radiation chemistry, i.e., the use of ionizing radiation from radioisotopes and accelerators to induce nanomaterials or chemical changes in materials, has proven to be a versatile tool for controlled manufacturing of both organic and inorganic nanoparticles. The advantages of using radiation chemistry for this purpose are many, such as low energy consumption, minimal use of potentially harmful chemicals and simple production schemes. For medical applications one more advantage is that the material can be sterile as manufactured. Radiation-induced synthesis can be carried out in aqueous systems, which minimizes the use of organic solvents and the need for separation and purification of the final product. The radiation chemistry of water is well known, as are the various ways of fine-tuning the reactivity of the system towards a desired target by adding different solutes. This, in combination with the controllable and adjustable irradiation process parameters, makes the technique superior to most other chemical methods. In this review, we discuss the fundamentals of radiation chemistry and radiation-induced synthesis of nanoparticles in aqueous solutions. The impact of dose and

  6. DESIGN OF ROBOTIC COLONIZER CONTROL SYSTEM FOR AQUEOUS ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    C.VENKATESH

    2013-05-01

    Full Text Available Now a days there is a huge interest on underwater communication systems for various applications in order to explore aqueous environments. Intelligent robots and cooperative multi- agent robotic systems can be very efficient tools to speed up search and research operations in remote areas. Robots are also useful to do jobs inareas and in situations that are hazardous for human, they can go anywhere that is not reachable my humans and can go into gaps and move trough small holes that are impossible for humans and even trained dogs. in this paper, a wireless underwater mobile robot system is designed in order to study the behavior of artemia group. anew idea has been presented for underwater mobile robot system which is consists of two parts, first is the underwater mechanical robot and the second is ZigBee wireless based mobile robot which controls and moves the first part. by this system different patterns motion control (linear, circular, zigzag, etc. has been performed and proved the ability to control group of robot by controlling the group of artemia and monitoring the underwater mobile robot control with the help of water proof RF wireless camera and also explore the details present around the mobile robot

  7. Monodisperse PEGylated spheres: an aqueous colloidal model system.

    Science.gov (United States)

    Ulama, Jeanette; Zackrisson Oskolkova, Malin; Bergenholtz, Johan

    2014-03-01

    Fluorinated core-shell spheres have been synthesized using a novel semibatch emulsion polymerization protocol employing slow feeding of the initiator. The synthesis results in aqueous dispersions of highly monodisperse spheres bearing a well-defined poly(ethylene glycol) graft (PEGylation). Measurements are consistent with the synthesis achieving a high grafting density that moreover consists of a single PEG layer with the polymer significantly elongated beyond its radius of gyration in bulk. The fluorination of the core of the particles confers a low index of refraction such that the particles can be refractive index matched in water through addition of relatively small amounts of a cosolvent, which enables the use of optical and laser-based methods for studies of concentrated systems. The systems exhibit an extreme stability in NaCl solutions, but attractions among particles can be introduced by addition of other salts, in which case aggregation is shown to be reversible. The PEGylated sphere dispersions are expected to be ideally suited as model systems for studies of the effect of PEG-mediated interactions on, for instance, structure, dynamics, phase behavior, and rheology. PMID:24533774

  8. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT; ULTRASONIC AQUEOUS CLEANING SYSTEMS, SMART SONIC CORPORATION, SMART SONIC

    Science.gov (United States)

    This report is a product of the U.S. EPA's Environmental Technoloy Verification (ETV) Program and is focused on the Smart Sonics Ultrasonic Aqueous Cleaning Systems. The verification is based on three main objectives. (1) The Smart Sonic Aqueous Cleaning Systems, Model 2000 and...

  9. Reticulation of Aqueous Polyurethane Systems Controlled by DSC Method

    Directory of Open Access Journals (Sweden)

    Jakov Stamenkovic

    2006-06-01

    Full Text Available The DSC method has been employed to monitor the kinetics of reticulation ofaqueous polyurethane systems without catalysts, and with the commercial catalyst of zirconium(CAT®XC-6212 and the highly selective manganese catalyst, the complex Mn(III-diacetylacetonemaleinate (MAM. Among the polyol components, the acrylic emulsions wereused for reticulation in this research, and as suitable reticulation agents the water emulsiblealiphatic polyisocyanates based on hexamethylendoisocyanate with the different contents ofNCO-groups were employed. On the basis of DSC analysis, applying the methods of Kissinger,Freeman-Carroll and Crane-Ellerstein the pseudo kinetic parameters of the reticulation reactionof aqueous systems were determined. The temperature of the examination ranged from 50oC to450oC with the heat rate of 0.5oC/min. The reduction of the activation energy and the increaseof the standard deviation indicate the catalytic action of the selective catalysts of zirconium andmanganese. The impact of the catalysts on the reduction of the activation energy is thestrongest when using the catalysts of manganese and applying all the three afore-said methods.The least aberrations among the stated methods in defining the kinetic parameters wereobtained by using the manganese catalyst.

  10. Novel incoherent scheme for photonic generation of biphase modulated UWB signals

    DEFF Research Database (Denmark)

    Yu, Xianbin; Gibbon, Timothy Braidwood; Zibar, Darko;

    2009-01-01

    A novel incoherent scheme for generation of direct-sequence binary biphase modulated ultrawideband (UWB) signals is proposed and experimentally demonstrated. There is no requirement for pulse shaper (optical filter) in our proposed system.......A novel incoherent scheme for generation of direct-sequence binary biphase modulated ultrawideband (UWB) signals is proposed and experimentally demonstrated. There is no requirement for pulse shaper (optical filter) in our proposed system....

  11. Aqueous Two Phase System Assisted Self-Assembled PLGA Microparticles

    Science.gov (United States)

    Yeredla, Nitish; Kojima, Taisuke; Yang, Yi; Takayama, Shuichi; Kanapathipillai, Mathumai

    2016-06-01

    Here, we produce poly(lactide-co-glycolide) (PLGA) based microparticles with varying morphologies, and temperature responsive properties utilizing a Pluronic F127/dextran aqueous two-phase system (ATPS) assisted self-assembly. The PLGA polymer, when emulsified in Pluronic F127/dextran ATPS, forms unique microparticle structures due to ATPS guided-self assembly. Depending on the PLGA concentration, the particles either formed a core-shell or a composite microparticle structure. The microparticles facilitate the simultaneous incorporation of both hydrophobic and hydrophilic molecules, due to their amphiphilic macromolecule composition. Further, due to the lower critical solution temperature (LCST) properties of Pluronic F127, the particles exhibit temperature responsiveness. The ATPS based microparticle formation demonstrated in this study, serves as a novel platform for PLGA/polymer based tunable micro/nano particle and polymersome development. The unique properties may be useful in applications such as theranostics, synthesis of complex structure particles, bioreaction/mineralization at the two-phase interface, and bioseparations.

  12. Primitive Liquid Water of the Solar System in an Aqueous Altered Carbonaceous Chondrite

    Science.gov (United States)

    Tsuchiyama, A.; Miyake, A.; Kitayama, A.; Matsuno, J.; Takeuchi, A.; Uesugi, K.; Suzuki, Y.; Nakano, T.; Zolensky, M. E.

    2016-01-01

    Non-destructive 3D observations of the aqueous altered CM chondrite Sutter's Mill using scanning imaging x-ray microscopy (SIXM) showed that some of calcite and enstatite grains contain two-phase inclusion, which is most probably composed of liquid water and bubbles. This water should be primitive water responsible for aqueous alteration in an asteroid in the early solar system.

  13. Two-phase aqueous micellar systems: an alternative method for protein purification

    Directory of Open Access Journals (Sweden)

    Rangel-Yagui C. O.

    2004-01-01

    Full Text Available Two-phase aqueous micellar systems can be exploited in separation science for the extraction/purification of desired biomolecules. This article reviews recent experimental and theoretical work by Blankschtein and co-workers on the use of two-phase aqueous micellar systems for the separation of hydrophilic proteins. The experimental partitioning behavior of the enzyme glucose-6-phosphate dehydrogenase (G6PD in two-phase aqueous micellar systems is also reviewed and new results are presented. Specifically, we discuss very recent work on the purification of G6PD using: i a two-phase aqueous micellar system composed of the nonionic surfactant n-decyl tetra(ethylene oxide (C10E4, and (ii a two-phase aqueous mixed micellar system composed of C10E4 and the cationic surfactant decyltrimethylammonium bromide (C10TAB. Our results indicate that the two-phase aqueous mixed (C10E4/C10TAB micellar system can improve significantly the partitioning behavior of G6PD relative to that observed in the two-phase aqueous C10E4 micellar system.

  14. Biphasic calcium phosphate in periapical surgery

    OpenAIRE

    Suneelkumar, Chinni; Datta, Krithika; Manali R Srinivasan; Kumar, Sampath T

    2008-01-01

    Calcium phosphate ceramics like hydroxyapatite and β -tricalcium phosphate (β -TCP) possess mineral composition that closely resembles that of the bone. They can be good bone substitutes due to their excellent biocompatibility. Biphasic calcium phosphate is a bone substitute which is a mixture of hydroxyapatite and β -tricalcium phosphate in fixed ratios. Studies have demonstrated the osteoconductive potential of this composition. This paper highlights the clinical use of biphasic calcium pho...

  15. 水/离子液体[BMIM]PF6两相体系中全细胞催化生成单葡萄糖醛酸基甘草次酸%Biosynthesis of glycyrrhetic acid 3-O-mono-β-D-glucuronide by whole cell in ionic liquid/water biphasic system

    Institute of Scientific and Technical Information of China (English)

    陈金燕; 邹树平; 何冬梅; 杨晓刚; 李春

    2011-01-01

    研究了水/离子液体两相体系中重组毕赤酵母Pichia pastoris GS115(r-PGUS-P)全细胞转化甘草酸(GL)生成单葡萄糖醛酸基甘草次酸(GAMG)的反应.确定最适反应体系为离子液体[BMIM] PF6/水(2∶8,体积比),最适缓冲液pH、反应温度、底物浓度和细胞加入量分别为5.4、45℃、6.O mmol·L-1和8.0g·L-1.在此条件下反应58 h,产物GAMG得率和化学键选择性分别为69.6%和67.2%,与纯水相反应体系相比,分别提高了12.4%和12.61%.离子液体循环使用7次后,回收利用率为93.47%.产物GAMG和副产物甘草次酸(GA)在此两相体系中得到有效分离,为后续产物分离带来便利.%Glycyrrhizin (GL), the biologically active compounds of liquorice, can be hydrolysed to glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG) by whole cells containing β-D-glucuronidase. GAMG is widely used in the pharmaceutical and food industries due to its stronger physiological functions, higher biological activity, more favorable sweetness, and lower caloric value as compared with GL. The recombinant Pichia pastoris (r-PGUS-P) designated in this work expressing β-D-glucuronidase, was used as a whole-cell biocatalyst catalyzing GL to GAMG in non-aqueous solvents systems. The results showed that r-PGUS-P gave the highest yield of GAMG in l-butyl-3-methylimidazolium hexafluorophosphate ( [BMIM] PF6 )/water (2 ∶ 8, vol) biphasic system. The optimal conditions of this reaction were determined as follows; optimum pH, substrate concentration, temperature and cell content were 5. 4, 6. 0 mmol · L-1, 45°C, and 8. 0 g · L-1, respectively. Under these optimized conditions, 69.6% yield of GAMG and 67. 2% of the chemical bond selectivity was achieved after 58 h reaction time, increase by 12. 4% and 12. 61%, respectively against aqueous phase. Simultaneously, the ionic liquid [BMIM]PF6 also remained at higher recovery percentage of about 93.47% during repeated use for 7 reaction cycles. Especially

  16. Thermodynamics of extraction of Plutonium(VI) in polyEthylene glycol (PEG) based aqueous biphasic system (ABS) using 18-crown-6 and 15-crown-5

    International Nuclear Information System (INIS)

    Extraction of plutonyl ion was studied using PEG-2000/(NH4)2SO4 (40% w/w of each) ABS with 18-crown-6 (18-C-6) as well as 15-crown-5 (15-C-5) as the extractants. The distribution follows the order 18-C-6>15-C-5 in accordance with their basicities of 0.40 and 0.29, respectively. The species extracted were identified to be (PuO2.18-C-6/15-C-5)SO4 by the usual slope ratio method. The thermodynamic parameters evaluated by temperature coefficient method showed that the reaction is favoured by lowering of enthalpy and counteracted by decrease in entropy. The large decrease in the enthalpy values (-20.4±1.8 kJ mol-1 and - 13.2±1.0 kJ mol-1 for 18-C-6 and 15-C-5, respectively) can be explained due to direct bonding of crown ether to the central metal atom (i.e. inner sphere complex) and not through hydrogen bonding as suggested previously by other workers. (orig.)

  17. Determination of the distribution constants of aromatic compounds and steroids in biphasic micellar phosphonium ionic liquid/aqueous buffer systems by capillary electrokinetic chromatography

    Czech Academy of Sciences Publication Activity Database

    Lokajová, Jana; Railila, A.; King, A. W. T.; Wiedmer, S. K.

    2013-01-01

    Roč. 1308, Sep 20 (2013), s. 144-151. ISSN 0021-9673 R&D Projects: GA TA ČR TA02010760 Institutional support: RVO:61388963 Keywords : critical micelle concentration * electrokinetic chromatography * distribution constant * PeakMaster * phosphonium ionic liquid Subject RIV: CC - Organic Chemistry Impact factor: 4.258, year: 2013

  18. 1,2,4-Triazine-picolinamide functionalized, nona-dentate chelates for the segregation of lanthanides(III) and actinides(III) in biphasic systems

    International Nuclear Information System (INIS)

    A novel family of nona-dentate ligands based on the (5,6-diphenyl-1,2,4-triazin-3-yl)-picolinamide donor moiety has been synthesized from simple starting materials in high yield and purity. This group of ligands is an addition to the neutral nona-dentate group but the first to incorporate 1,2,4-triazine. Their ability to extract a select group of lanthanides from acidic aqueous solution has been correlated to their ability to meet the ideal trigonal tri-capped prismatic geometry that is seen by lanthanides and actinides in aqueous solution. The rate of metallation was determined using UV/VIS spectroscopy with pseudo first order conditions and showed similar behaviour to literature examples. Theoretical calculations were used to probe the bonding structure with lanthanides and actinides to predict the potential Ln/An segregating ability of the new ligands. (authors)

  19. A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

    OpenAIRE

    Andrew Bogdan; D. Tyler McQuade

    2009-01-01

    We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leavi...

  20. Phase behaviour of tertiary recovery sulfonates - petroleum fractions - aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Ghoniem, S.A.; Darwish, T.A.; Salamah, A.O.

    1988-02-01

    The phase behaviour of tertiary recovery sulfonates having commercial names TRS-10, TRS-16 and TRS-40 with aqueous phase and light petroleum fractions (non polar kerosene and gasoline) was studied at 20, 40 and 60/sup 0/C. The adopted pseudo components of the ternary diagram are hydrocarbon, surfactant and aqueous phase. The aqueous phase was composed of bidistilled water in addition to different proportions of pure alcohols and sodium chloride. The tested alcohols included methanol, ethanol, iso-propanol, n-butanol and n-pentanol. Thus, the best alcohol type and concentration in addition to optimum salinity, which correspond to maximum single phase region, were established for each surfactant at the various tested temperatures. It was shown that higher the affinity of the tested surfactant for hydrocarbon phase, the greater is the solubility of the corresponding optimum co-surfactant in water. The variation of optimum alcohol concentration with temperature, the effect of salt on the single phase region and the effect of hydrocarbon phase on the observed phenomena were discussed and found to agree with the previously established theories.

  1. Water/Oil Biphasic Hydroformylation of Higher Olefins over a TPPTS-Rh/SiO2 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Hejun Zhu; Yunjie Ding; Fu Yang; Li Yan; Jianmin Xiong; Hongmei Yin; Liwu Lin

    2004-01-01

    A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous highsurface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene.

  2. Inhibition Effect of Mace Extract Microemulsion on Vitamin C Photooxidation in Aqueous Systems

    Directory of Open Access Journals (Sweden)

    Hasbullah Hasbullah

    2014-01-01

    Full Text Available Photooxidation in food systems cause nutritional losses and produces undesirable flavor, toxic and color compounds, which make foods less acceptable or unacceptable to consumers. The objective of this research was to know the effectiveness of mace extract microemulsion to inhibit vitamin C photooxidation in aqueous systems. Aqueous food systems used are both beverage model system and apple juice beverage, where in each system enriched by 100 ppm vitamin C as substrate and 20 ppm erytrosin as photosensitiser. It is about one percent and two percent of microemulsion that contain mace extract of 0, 500 and 750 ppm were added into each of aqueous food system. Inhibition effect of mace extract microemulsion toward vitamin C photooxidation based on the rate of vitamin C degradation in aqueous food systems that illuminated by fluorescent light with 2000 lux intensity within eight hours. The result indicated the mace extract microemulsion has anti-photooxidation activity and ability to inhibit vitamin C photooxidation in aqueous systems.

  3. Radiation formation of colloidal silver particles in aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Cuba, Vaclav [CTU in Prague, Faculty of Nuclear Sciences and Physical Engineering, Brehova 7, 115 19 Prague 1 (Czech Republic)], E-mail: vaclav.cuba@fjfi.cvut.cz; Nemec, Mojmir; Gbur, Tomas; John, Jan; Pospisil, Milan; Mucka, Viliam [CTU in Prague, Faculty of Nuclear Sciences and Physical Engineering, Brehova 7, 115 19 Prague 1 (Czech Republic)

    2010-04-15

    This paper reports on the formation of silver nanoparticles initiated by gamma and UV radiation in various aqueous solutions. Inorganic precursors were used for radiation and/or photochemical reduction of Ag{sup +} ions to a metallic form. The influence of various parameters on the nucleation and formation of colloid particles was studied. Attention was also focused on the composition of the irradiated solution. Aliphatic alcohols were used as scavengers of OH radicals and other oxidizing species. The influence of the stabilizers on the formation and stability of the nanoparticles was studied.

  4. Biphasic Effects of α-Asarone on Immobility in the Tail Suspension Test: Evidence for the Involvement of the Noradrenergic and Serotonergic Systems in Its Antidepressant-Like Activity

    Science.gov (United States)

    Chellian, Ranjithkumar; Pandy, Vijayapandi; Mohamed, Zahurin

    2016-01-01

    Alpha (α)-asarone is one of the main psychoactive compounds, present in Acorus species. Evidence suggests that the α-asarone possess an antidepressant-like activity in mice. However, the exact dose-dependent effect of α-asarone and mechanism(s) involved in the antidepressant-like activity are not clear. The present study aimed to investigate the dose-dependent effect of α-asarone and the underlining mechanism(s) involved in the antidepressant-like activity of α-asarone in the mouse model of tail suspension test (TST). In this study, the acute effect of α-asarone per se at different doses (10–100 mg/kg, i.p.) on immobility in the TST was studied. Additionally, the possible mechanism(s) involved in the antidepressant-like effect of α-asarone was studied using its interaction with noradrenergic and serotonergic neuromodulators in the TST. The present results reveal that the acute treatment of α-asarone elicited biphasic responses on immobility such that the duration of the immobility time is significantly reduced at lower doses (15 and 20 mg/kg, i.p.) but increased at higher doses (50 and 100 mg/kg, i.p.) in the TST. Besides, α-asarone at higher doses (50 and 100 mg/kg, i.p.) significantly decreased the spontaneous locomotor activity. Moreover, pretreatment of mice with noradrenergic neuromodulators such as AMPT (100 mg/kg, i.p., a catecholamine synthesis inhibitor), prazosin (1 mg/kg, i.p., an α1-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α2-adrenoceptor antagonist) and with serotonergic neuromodulators such as PCPA (100 mg/kg, i.p., once daily for four consecutive days, a serotonin synthesis inhibitor,) and WAY100635 (0.1 mg/kg, s.c., a selective 5-HT1A receptor antagonist) significantly reversed the anti-immobility effect of α-asarone (20 mg/kg, i.p.). Taken together, our results suggest that the acute treatment with α-asarone elicited biphasic actions in the TST in which antidepressant-like effect was seen at relatively lower doses (15

  5. A stable liquid–liquid extraction system for clavulanic acid using polymer-based aqueous two-phase systems

    OpenAIRE

    Pereira, Jorge F. B.; Santos, Valéria Carvalho; Johansson, Hans-Olof; J. A. Teixeira; Pessoa Júnior, Adalberto

    2012-01-01

    The partitioning of Clavulanic Acid (CA) in a novel inexpensive and stable aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The aqueous two-phase systems are formed by mixing both polymers with a salt (NaCl or Na2SO4) and an aqueous solution of CA. The stability of CA on the presence of both polymers was investigated and it was observed that these polymers do not degrade the biomolecule. The effect of PEG-molecular ...

  6. Current Development in the Heterogenization of Homogeneous Catalysis——Fluorous Biphase System%均相催化多相化新进展——氟两相体系

    Institute of Scientific and Technical Information of China (English)

    鲁福身; 晁建平; 杨春育

    2001-01-01

    The FBS (fluorous biphase system) makes homogeneous catalysis and heterogeneous separation possible and easy to separate the catalysts dissolved in PFC (perfluorocarbons). Current developments in the chemistry of FBS and fluorous syntheses, including fluorous soluble ligands, catalysts and reagents are summarized. Numerous applications of FBS in hydroformylation, hydroboration and other organic reactions are also discussed.%氟两相体系实现了均相催化多相化,可以方便地分离溶解在PFC中的催化剂。本文综述了氟两相体系及氟合成领域,包括氟溶配体、催化剂和反应物等方面的最新进展。对氟两相体系在烯烃的氢甲酰化反应、硼氢化反应以及其它有机反应中的广泛应用作了讨论。

  7. Correlations for the partition behavior of proteins in aqueous two-phase systems

    DEFF Research Database (Denmark)

    Schmidt, A.S.; Andrews, B.A.; Asenjo, J.A.

    1996-01-01

    The effect of protein concentration in partitioning in PEG/ salt aqueous two-phase systems has been investigated. PEG 4000/phosphate systems in the presence of 0% w/w and 8.8% w/w NaCl have been evaluated using amyloglucosidase, subtilisin, and trypsin inhibitor. Also, a PEG 4000/phosphate system...

  8. Mineralogic controls on aqueous neptunium(V) concentrations in silicate systems

    International Nuclear Information System (INIS)

    The presence of radioactive neptunium in commercially spent nuclear fuel is problematic due to its mobility in environmental systems upon oxidation to the pentavalent state. As uranium is the major component of spent fuel, incorporation of neptunium into resulting U(VI) mineral phases would potentially influence its release into environmental systems. Alternatively, aqueous neptunium concentrations may be buffered by solid phase Np2O5. In this study, we investigate both of these controls on aqueous neptunium(V) concentrations. We synthesize two uranyl silicates, soddyite, (UO2)2SiO4·2H2O, and boltwoodite, (K, Na)(UO2)(SiO3OH)·1.5H2O, each in the presence of two concentrations of aqueous Np(V). Electron microscopy and electron diffraction analyses of the synthesized phases show that while significant neptunyl incorporation occurred into soddyite, the Np(V) in the boltwoodite systems largely precipitated as a secondary phase, Np2O5(s). The release of Np(V) from each system into aqueous solution was measured for several days, until steady-state concentrations were achieved. Using existing solubility constants (Ksp) for pure soddyite and boltwoodite, we compared predicted equilibrium aqueous U(VI) concentrations with the U(VI) concentrations released in the solubility experiments. Our experiments reveal that Np(V) incorporation into soddyite increases the concentration of aqueous U in equilibrium with the solid phase, perhaps via the formation of a metastable phase. In the mixed boltwoodite – Np2O5(s) system, the measured aqueous U(VI) activities are consistent with those predicted to be in equilibrium with boltwoodite under the experimental conditions, a result that is consistent with our conclusion that little Np(V) incorporation occurred into the boltwoodite. In the boltwoodite systems, the measured Np concentrations are likely controlled by the presence of Np2O5 nanoparticles, suggesting an additional potential mobility vector for Np in geologic systems. Our

  9. Monitoring corrosion and chemistry phenomena in supercritical aqueous systems

    International Nuclear Information System (INIS)

    The in situ monitoring of the chemistry and electrochemistry of aqueous heat transport fluids in thermal (nuclear and fossil) power plants is now considered essential if adequate assessment and close control of corrosion and mass transfer phenomena are to be achieved. Because of the elevated temperatures and pressures involved. new sensor technologies are required that are able to measure key parameters under plant operating conditions for extended periods of time. In this paper, the authors outline a research and development program that is designed to develop practical sensors for use in thermal power plants. The current emphasis is on sensors for measuring corrosion potential, pH, the concentrations of oxygen and hydrogen, and the electrochemical noise generated by corrosion processes at temperatures ranging from ∼250 C to 500 C. The program is currently at the laboratory stage, but testing of prototype sensors in a coal-fired supercritical power plant in Spain will begin shortly

  10. Extraction Equilibrium of Acrylic Acid by Aqueous Two-Phase Systems Using Hydrophilic Ionic Liquids

    International Nuclear Information System (INIS)

    As an effective method for extraction of acrylic acid, aqueous two-phase systems based on morpholinium ionic liquids were used in this study. Effects of the alkyl chain length of cation in morpholinium ionic liquids on phase diagram and extraction efficiencies were investigated. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of morpholinium ionic liquids to aqueous K2HPO4 solutions. It can be found that the ability of morpholinium ionic liquids for phase separation followed the order [HMMor][Br]>[OMMor][Br]>[BMMor][Br]>[EMMor][Br]. There was little difference between binodal curves of imidazolium ionic liquids and those of morpholinium ionic liquids. 50-90% of the extraction efficiency was observed for acrylic acid by aqueous two phase extraction of acrylic acid with morpholinium ionic liquids. It can be concluded that morpholinium ionic liquids/K2HPO4 were effective for aqueous two phases extraction of acrylic acid comparing to imidazolium ionic liquids/K2HPO4 systems because of their lower cost

  11. A new kinetic biphasic approach applied to biodiesel process intensification

    Energy Technology Data Exchange (ETDEWEB)

    Russo, V.; Tesser, R.; Di Serio, M.; Santacesaria, E. [Naples Univ. (Italy). Dept. of Chemistry

    2012-07-01

    Many different papers have been published on the kinetics of the transesterification of vegetable oil with methanol, in the presence of alkaline catalysts to produce biodiesel. All the proposed approaches are based on the assumption of a pseudo-monophasic system. The consequence of these approaches is that some experimental aspects cannot be described. For the reaction performed in batch conditions, for example, the monophasic approach is not able to reproduce the different plateau obtained by using different amount of catalyst or the induction time observed at low stirring rates. Moreover, it has been observed by operating in continuous reactors that micromixing has a dramatic effect on the reaction rate. At this purpose, we have recently observed that is possible to obtain a complete conversion to biodiesel in less than 10 seconds of reaction time. This observation is confirmed also by other authors using different types of reactors like: static mixers, micro-reactors, oscillatory flow reactors, cavitational reactors, microwave reactors or centrifugal contactors. In this work we will show that a recently proposed biphasic kinetic approach is able to describe all the aspects before mentioned that cannot be described by the monophasic kinetic model. In particular, we will show that the biphasic kinetic model can describe both the induction time observed in the batch reactors, at low stirring rate, and the very high conversions obtainable in a micro-channel reactor. The adopted biphasic kinetic model is based on a reliable reaction mechanism that will be validated by the experimental evidences reported in this work. (orig.)

  12. Biphasic synovial sarcoma of oral cavity

    International Nuclear Information System (INIS)

    Synovial sarcoma is a mesenchymal spindle cell tumour, which is unrelated to synovium and shows variable epithelial differentiation. Typically, synovial sarcoma arises in the soft tissues of the extremities but cases in the head and neck region are less common and oral cavity involvement is extremely rare. A 17-year-old girl presented with a gradually increasing swelling on the right cheek for 2 years, which on biopsy, revealed a biphasic tumour comprising fascicles of spindle shaped cells with gland formation by epithelial cells and scattered masts cells. Histological diagnosis of biphasic synovial sarcoma was confirmed on immunohistochemistry by strong positivity for EMA, S-100 and CD-99 in both epithelial as well as spindle cell areas. (author)

  13. Primary biphasic synovial sarcoma of the orbit.

    OpenAIRE

    Ratnatunga, N.; Goodlad, J. R.; Sankarakumaran, N.; Seimon, R.; Nagendran, S.; Fletcher, C D

    1992-01-01

    Synovial sarcoma is one of the most common soft tissue malignancies of adolescents and young adults. Despite its name, it is no longer thought to be histogenetically derived from the synovium. What seems to be the first case of synovial sarcoma to arise in the orbit presented in a 21 year old woman as a slowly enlarging subconjunctival mass. Although this tumour was typically biphasic, the monophasic spindle cell variant arising at this site could easily be confused with less aggressive orbit...

  14. Geomorphic and Aqueous Chemistry of a Portion of the Upper Rio Tinto System, Spain

    Science.gov (United States)

    Osburn, M. R.; Fernandez-Remolar, D. C.; Arvidson, R. E.; Morris, R. V.; Ming, D.; Prieto-Ballesteros, O.; Amils, R.; Stein, T. C.; Heil-Chapdelaine, V.; Friedlander, L. R.; Herndon, B.; Marlow, J.; Rosenberg, S.; Scherpker, K.; Steiner, A.

    2007-01-01

    Observations from the two Mars rovers, Spirit and Opportunity, combined with discoveries of extensive hydrated sulfate deposits from OMEGA and CRISM show that aqueous deposition and alteration involving acidic systems and sulfate deposition has been a key contributor to the martian geologic record. Rio Tinto, Spain, provides a process model for formation of sulfates on Mars by evaporation of acidic waters within shallow fluvial pools, particularly during dry seasons. We present results from a detailed investigation of an upper portion of the Rio Tinto, focusing on geomorphology, clastic sediment transport, and acidic aqueous processes. We also lay out lessons-learned for under-standing sulfate formation and alteration on Mars.

  15. Facile catalyst separation without water: Fluorous biphase hydroformylation of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, I.T.; Rabai, J. [Exxon Research and Engineering Co., Annandale, NJ (United States)

    1994-10-07

    A novel concept for performing stoichiometric and catalytic chemical transformations has been developed that is based on the limited miscibility of partially or fully fluorinated compounds with nonfluorinated compounds. A fluorous biphase system (FBS) consists of a fluorous phase containing a dissolved reagent or catalyst and another phase, which could be any common organic or nonorganic solvent with limited or no solubility in the fluorous phase. The fluorous phase is defined as the fluorocarbon (mostly perfluorinated alkanes, ethers, and tertiary amines)-rich phase of a biphase system. An FBS compatible reagent or catalyst contains enough fluorous moieties that it will be soluble only or preferentially in the fluorous phase. The most effective fluorous moieties are linear or branched perfuoralkyl chains with high carbon number; they may also contain heteroatoms. The chemical transformation may occur either in the fluorous phase or at the interface of the two phases. The application of FBS has been demonstrated for the extraction of rhodium from toluene and for the hydroformylation of olefins. The ability to separate a catalyst or a reagent from the products completely at mild conditions could lead to industrial application of homogeneous catalysts or reagents and to the development of more environmentally benign processes.

  16. Separation of aqueous two-phase polymer systems in microgravity

    Science.gov (United States)

    Vanalstine, J. M.; Harris, J. M.; Synder, S.; Curreri, P. A.; Bamberger, S. B.; Brooks, D. E.

    1984-01-01

    Phase separation of polymer systems in microgravity is studied in aircraft flights to prepare shuttle experiments. Short duration (20 sec) experiments demonstrate that phase separation proceeds rapidly in low gravity despite appreciable phase viscosities and low liquid interfacial tensions (i.e., 50 cP, 10 micro N/m). Ostwald ripening does not appear to be a satisfactory model for the phase separation mechanism. Polymer coated surfaces are evaluated as a means to localize phases separated in low gravity. Contact angle measurements demonstrate that covalently coupling dextran or PEG to glass drastically alters the 1-g wall wetting behavior of the phases in dextran-PEG two phase systems.

  17. Ionic Liquid-salt Aqueous Two-phase System, a Novel System for the Extraction of Abused Drugs

    Institute of Scientific and Technical Information of China (English)

    She Hong LI; Chi Yang HE; Hu Wei LIU; Ke An LI; Feng LIU

    2005-01-01

    A 1-butyl-3-methylimidazolium chloride-salt aqueous two-phase system was studied on extraction of abused drugs. The effects of sorts of salts, temperature, concentration of salt and drugs on system were investigated systematically. A satisfactory extraction efficiency of 93%was obtained for papaverine while that of morphine was 65%. The extraction mechanism was primarily discussed.

  18. Study of the anti-inflammatory effects of low-dose radiation. The contribution of biphasic regulation of the antioxidative system in endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Large, Martin; Hehlgans, Stephanie; Reichert, Sebastian; Roedel, Claus; Roedel, Franz [Goethe University Frankfurt, Department of Radiotherapy and Oncology, Frankfurt am Main (Germany); Gaipl, Udo S. [University Hospital Erlangen, Department of Radiation Oncology, Erlangen (Germany); Fournier, Claudia [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Darmstadt (Germany); Weiss, Christian [Goethe University Frankfurt, Department of Radiotherapy and Oncology, Frankfurt am Main (Germany); Klinikum Darmstadt, Institute for Radiooncology and Radiotherapy, Darmstadt (Germany)

    2015-09-15

    We examined (a) the expression of the antioxidative factor glutathione peroxidase (GPx) and the transcription factor nuclear factor E2-related factor 2 (Nrf2) following low-dose X-irradiation in endothelial cells (ECs) and (b) the impact of reactive oxygen species (ROS) and Nrf2 on functional properties of ECs to gain further knowledge about the anti-inflammatory mode of action of low doses of ionizing radiation. EA.hy926 ECs and primary human dermal microvascular ECs (HMVEC) were stimulated by tumor necrosis factor-α (TNF-α, 20 ng/ml) 4 h before irradiation with single doses ranging from 0.3 to 3 Gy. The expression and activity of GPx and Nrf2 were analyzed by flow cytometry, colorimetric assays, and real-time PCR. The impact of ROS and Nrf2 on peripheral blood mononuclear cell (PBMC) adhesion was assayed in the presence of the ROS scavenger N-acetyl-L-cysteine (NAC) and Nrf2 activator AI-1. Following a low-dose exposure, we observed in EA.hy926 EC and HMVECs a discontinuous expression and enzymatic activity of GPx concomitant with a lowered expression and DNA binding activity of Nrf2 that was most pronounced at a dose of 0.5 Gy. Scavenging of ROS by NAC and activation of Nrf2 by AI-1 significantly diminished a lowered adhesion of PBMC to EC at a dose of 0.5 Gy. Low-dose irradiation resulted in a nonlinear expression and activity of major compounds of the antioxidative system that might contribute to anti-inflammatory effects in stimulated ECs. (orig.) [German] Ziel der Studie war die Untersuchung der Expression des antioxidativen Enzyms Glutathionperoxidase (GPx) und des Transkriptionsfaktors ''nuclear factor E2-related factor 2'' (Nrf2) in Endothelzellen nach niedrigdosierter Roentgenbestrahlung. Des Weiteren wurde der Einfluss von reaktiven Sauerstoffmetaboliten (ROS) und von Nrf2 auf funktionelle Eigenschaften von Endothelzellen analysiert, um weitere Erkenntnisse ueber die antientzuendliche Wirkung von niedrigdosierten Roentgenstrahlen

  19. Study of the anti-inflammatory effects of low-dose radiation. The contribution of biphasic regulation of the antioxidative system in endothelial cells

    International Nuclear Information System (INIS)

    We examined (a) the expression of the antioxidative factor glutathione peroxidase (GPx) and the transcription factor nuclear factor E2-related factor 2 (Nrf2) following low-dose X-irradiation in endothelial cells (ECs) and (b) the impact of reactive oxygen species (ROS) and Nrf2 on functional properties of ECs to gain further knowledge about the anti-inflammatory mode of action of low doses of ionizing radiation. EA.hy926 ECs and primary human dermal microvascular ECs (HMVEC) were stimulated by tumor necrosis factor-α (TNF-α, 20 ng/ml) 4 h before irradiation with single doses ranging from 0.3 to 3 Gy. The expression and activity of GPx and Nrf2 were analyzed by flow cytometry, colorimetric assays, and real-time PCR. The impact of ROS and Nrf2 on peripheral blood mononuclear cell (PBMC) adhesion was assayed in the presence of the ROS scavenger N-acetyl-L-cysteine (NAC) and Nrf2 activator AI-1. Following a low-dose exposure, we observed in EA.hy926 EC and HMVECs a discontinuous expression and enzymatic activity of GPx concomitant with a lowered expression and DNA binding activity of Nrf2 that was most pronounced at a dose of 0.5 Gy. Scavenging of ROS by NAC and activation of Nrf2 by AI-1 significantly diminished a lowered adhesion of PBMC to EC at a dose of 0.5 Gy. Low-dose irradiation resulted in a nonlinear expression and activity of major compounds of the antioxidative system that might contribute to anti-inflammatory effects in stimulated ECs. (orig.)

  20. Ion mixing, hydration, and transport in aqueous ionic systems

    International Nuclear Information System (INIS)

    The enhancement effect on the ion mobility of fluoride (and that of chloride) in a polycationic system, as the chloride content increases, is shown to also exist in other more simple ionic systems with cations such as the cesium ion and an organic ammonium ion. As the chloride content increases, in addition to the finding that there is more unbound water associated with the cation, we also observe that the average lifetime of a hydrogen bond decreases. This change to the hydrogen bonds is correlated to significant changes to both the structural and dynamical properties of water. The more disordered water structure and faster water dynamics are hypothesized to be also responsible for the enhanced ion mobilities. Furthermore, when either the chloride content or hydration level is changed, the self-diffusion constant of each co-ion changes by almost the same factor, implying the existence of a single universal transport mechanism that determines ion mobilities

  1. Development of ketoprofen delivery systems based on aqueous polyurethane dispersions

    OpenAIRE

    Leite, E; Fernandes, I; Ayres, E.; Barreiro, M.F.; Silva-Cunha, A.

    2013-01-01

    Ketoprofen (2-(3-benzoylphenyl) propionic acid) is a non-steroidal anti-inflammatory drug (NSAID) used to treat a wide range of acute and chronic inflammatory diseases, e.g., rheumatoid arthritis, osteoarthritis and ankylosing spondylitis. Its prolonged oral administration is associated with several gastrointestinal reactions such as irritation and ulceration. In this context, ketoprofen is a good candidate for controlled release administration systems. This work aims to test the suitabili...

  2. Binary Nucleation in Aqueous Electrolyte Systems. Sodium Chloride

    Czech Academy of Sciences Publication Activity Database

    Němec, Tomáš; Maršík, František

    Gdansk: IFFM Publishers, 2005 - (Mikielewicz, J.; Butrymowicz, D.; Trela, M.; Cieslinski, J.), s. 395-400 ISBN 83-88237-90-X. [HEAT 2005 : International Conference on Transport Phenomena in Multiphase Systems. Gdansk (PL), 26.06.2005-30.06.2005] R&D Projects: GA ČR(CZ) GA101/05/2536 Institutional research plan: CEZ:AV0Z20760514 Keywords : binary nucleation * sodium chloride * water Subject RIV: BJ - Thermodynamics

  3. Dissolution state of cellulose in aqueous systems. 2. Acidic solvents.

    Science.gov (United States)

    Alves, Luis; Medronho, Bruno; Antunes, Filipe E; Topgaard, Daniel; Lindman, Björn

    2016-10-20

    Cellulose is insoluble in water but can be dissolved in strong acidic or alkaline conditions. How well dissolved cellulose is in solution and how it organizes are key questions often neglected in literature. The typical low pH required for dissolving cellulose in acidic solvents limits the use of typical characterization techniques. In this respect, Polarization Transfer Solid State NMR (PT ssNMR) emerges as a reliable alternative. In this work, combining PT ssNMR, microscopic techniques and X-ray diffraction, a set of different acidic systems (phosphoric acid/water, sulfuric acid/glycerol and zinc chloride/water) is investigated. The studied solvent systems are capable to efficiently dissolve cellulose, although degradation occurs to some extent. PT ssNMR is capable to identify the liquid and solid fractions of cellulose, the degradation products and it is also sensitive to gelation. The materials regenerated from the acidic dopes were found to be highly sensitive to the solvent system and to the presence of amphiphilic additives in solution. PMID:27474617

  4. Rapid RNA Exchange in Aqueous Two-Phase System and Coacervate Droplets

    OpenAIRE

    Jia, Tony Z.; Hentrich, Christian; SZOSTAK, JACK W.

    2014-01-01

    Compartmentalization in a prebiotic setting is an important aspect of early cell formation and is crucial for the development of an artificial protocell system that effectively couples genotype and phenotype. Aqueous two-phase systems (ATPSs) and complex coacervates are phase separation phenomena that lead to the selective partitioning of biomolecules and have recently been proposed as membrane-free protocell models. We show in this study through fluorescence recovery after photobleaching (FR...

  5. Temperature dependence of microwave absorption phenomena in single and biphase soft magnetic microwires

    Czech Academy of Sciences Publication Activity Database

    El Kammouni, R.; Vázquez, M.; Lezama, L.; Kurlyandskaya, G.; Kraus, Luděk

    2014-01-01

    Roč. 368, Nov (2014), 126-132. ISSN 0304-8853 Institutional support: RVO:68378271 Keywords : magnetic microwire * ferromagnetic resonance * microwave absorption * biphase magnetic system Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.970, year: 2014

  6. Critical issues in the use of metals and alloys in sulphur-containing aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, D.D.

    1992-12-31

    Sulphur-containing aqueous fluids are amongst the most corrosive environments experienced in industrial and natural systems. The high corrosivity is due principally to the wide range of oxidation states that sulphur may exist in within the thermodynamic stability domain of water, as well as to the high lability of many sulphur species, such as the polythionic acids and polysulfides. Additionally, sulphur, along with arsenic, antimony, and mercury, effectively promotes the entry of hydrogen into metal and alloy matrices, thereby leading to hydrogen damage and hydrogen embrittlement. In this paper, the chemistry of sulphur species in aqueous solutions and of the various iron sulphides is reviewed with emphasis on illustrating the diverse nature of metal/sulphur interactions. Finally, we identify a number of critical issues that need to be resolved to greatly improve our understanding of the chemistry of sulphur-containing systems and to improve our ability to predict the form and extent of corrosion in geochemical and geoenergy systems.

  7. Critical issues in the use of metals and alloys in sulphur-containing aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, D.D.

    1992-01-01

    Sulphur-containing aqueous fluids are amongst the most corrosive environments experienced in industrial and natural systems. The high corrosivity is due principally to the wide range of oxidation states that sulphur may exist in within the thermodynamic stability domain of water, as well as to the high lability of many sulphur species, such as the polythionic acids and polysulfides. Additionally, sulphur, along with arsenic, antimony, and mercury, effectively promotes the entry of hydrogen into metal and alloy matrices, thereby leading to hydrogen damage and hydrogen embrittlement. In this paper, the chemistry of sulphur species in aqueous solutions and of the various iron sulphides is reviewed with emphasis on illustrating the diverse nature of metal/sulphur interactions. Finally, we identify a number of critical issues that need to be resolved to greatly improve our understanding of the chemistry of sulphur-containing systems and to improve our ability to predict the form and extent of corrosion in geochemical and geoenergy systems.

  8. Synthesis and characterization of magnesium substituted biphasic mixtures of controlled hydroxyapatite/β-tricalcium phosphate ratios

    International Nuclear Information System (INIS)

    The present paper investigates the preparation of magnesium (Mg) substituted biphasic mixtures of different hydroxyapatite (HAP)/β-tricalcium phosphate (β-TCP) ratios through aqueous precipitation method. The concentrations of added magnesium (Mg) were varied with the calcium in order to obtain constant (Ca+Mg)/P ratios of 1.67 ranging from 1.62+0.05, 1.58+0.09 and 1.54+0.13, respectively. The as prepared powders were calcined at different temperatures to study the phase behaviour and thermal stability. The powders were characterized by the following analytical techniques: TG-DTA, X-ray diffraction and FT-IR. The results have shown that substitution of Mg in the calcium-deficient apatites resulted in the formation of biphasic mixtures of different HAP/β-TCP ratios after heating above 700 deg. C. The ratios of the formation of phase mixtures were dependent on the calcium deficiency in the apatites with the higher deficiency having the strongest impact on the increased formation of β-TCP and the substituted Mg was found to stabilize the β-TCP phase. - Graphical abstract: Role of Mg in the behaviour of calcium-deficient apatites during calcination to form biphasic mixtures

  9. Radiation Effects of Hydroxypropyl Methylcellulose Phthalate in Aqueous System

    International Nuclear Information System (INIS)

    Natural polymers and their derivatives were regarded as radiation degradation type polymer for a long time. However, since the successful crosslinking of CMC in so call paste-like status, quite a few natural polymer derivatives were found to be capable of crosslinking via irradiation. Hydroxypropyl methylcellulose phthalate (HPMCP) is water-insoluble cellulose ether with phthalate substitution and is widely used in the pharmaceutical industry due to its resistance to hydrolysis. It was found to be radiation-crosslinkable in basic solution and some organic solvents, but the gelation dose (Dg) was rather high (ca. 50 kGy). In this study, effects of two crosslinkers, i.e. methyl N, N-bis-acrylamide (bis) and ethyleneglycol dimethacrylate (EGDMA), on the accelerating of radiation crosslinking of HPMCP was studied. Intrinsic viscosities of HPMCP solution with various concentrations (10-20%) irradiated at different dose were determined to find the critical concentration for crosslinking of HPMCP and to understand the behavior of HPMCP solution before gel formation. Ion-specific swelling behavior of HPMCP hydrogel in various kinds of salt solutions was investigated to elucidate the interactions between different ion species and HPMCP. The results showed that (1) bis was apparently effective for accelerating the crosslinking of HPMCP; intrinsic viscosities of 20% HPMCP was found to be increased with increasing absorbed dose and vice versa for 10% HPMCP, implying that in paste-like status HPMCP followed crosslinking mechanism even before the formation of hydrogel; ion-specific swelling of HPMCP hydrogel without ion-exchange treatment was in good accordance with normal polyelectrolyte hydrogel except in high concentration KF solution. These results will be valuable for the processing and designing of HPMCP-based controlled release system

  10. Aqueous Transport Code Revisions Using Geographic Information Systems

    International Nuclear Information System (INIS)

    STREAM II, developed at the Savannah River Site (SRS) for execution on a personal computer, is an emergency response code that predicts downstream pollutant concentrations for releases from the SRS area to the Savannah River for emergency response management decision making. The STREAM II code consists of pre-processor, calculation, and post-processor modules. The pre-processor module provides a graphical user interface (GUI) for inputting the initial release data. The GUI passes the user specified data to the calculation module that calculates the pollutant concentrations at downstream locations and the transport times. The calculation module of the STREAM II adopts the transport module of the WASP5 code. WASP5 is a US Environmental Protection Agency water quality analysis program that simulates pollutant transport and fate through surface water using a finite difference method to solve the transport equation. The calculated downstream pollutant concentrations and travel times a re passed to the post-processor for display on the computer screen in graphical and tabular forms. To minimize the user's effort in the emergency situation, the required input parameters are limited to the time and date of release, type of release, location of release, amount and duration of release, and the calculation units. The user, however, could only select one of the seventeen predetermined locations. Hence, STREAM II could not be used for situations in which release locations differ from the seventeen predetermined locations. To eliminate this limitation, STREAM II has been revised to allow users to select the release location anywhere along the specified SRS main streams or the Savannah River by mouse-selection from a map displayed on the computer monitor. The required modifications to STREAM II using geographic information systems (GIS) software is discussed in this paper

  11. Selective separation of protein and saccharides by ionic liquids aqueous two-phase systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the present work,it was found that aqueous solution of a hydrophilic ionic liquid (IL),1-butyl-3-methylimidazolium dicyanamide ([C4mim][N(CN)2]),could be separated into an aqueous two-phase system (ATPS) by inorganic salts such as K2HPO4 and K3PO4.The top phase is IL-rich,while the bottom phase is phosphate-rich.It was shown that 82.7%-100% bovine serum albumin (BSA) could be enriched into the top phase and almost quantitative saccharides (arabinose,glucose,sucrose,raffinose or dextran) were preferentially extracted into the bottom phase in a single-step extraction by [C4mim][N(CN)2] + K2HPO4 ATPS.The extraction efficiency of BSA from the aqueous saccharide solutions was influenced by the molecular structure of saccharides.The conductivity,dynamic light scattering (DLS) and transmission electron microscopy (TEM) were combined to investigate the microstructure of the IL-rich top phase and the possible mechanism for the selective separation.It is suggested that the formation of the IL aggregate and the IL aggregate-BSA complex plays a significant role in the separation of BSA from aqueous saccharide solutions.This is the first example for the selective separation by ILs-based ATPSs.It is expected that these findings would have potential applications in bio-analysis,separation,and IL recycle.

  12. Integrated extraction and purification of soy isoflavones by using aqueous micellar systems.

    Science.gov (United States)

    Cordisco, Estefanía; Haidar, Carla N; Coscueta, Ezequiel R; Nerli, Bibiana B; Malpiedi, Luciana P

    2016-12-15

    In this work, an integration of solid-liquid and liquid-liquid extractions by using aqueous micellar two-phase systems was evaluated as potential tool to purify soy isoflavones. Additionally, the proposed methodology aimed to preserve the protein content of the processed soy flour. The extractive assays were performed in AMTPS formed by Triton X-114 and sodium tartrate. In order to optimize the purification process, temperature and time were evaluated as independent variables. Under optimal working conditions, i.e. 100min and 33°C of incubation, IF were purified with a recovery percentage of 93 and a purification factor of almost 10. More importantly, the obtained sample presented an aglycone proportion superior to the reported by other methodologies. These results open perspectives to the use of aqueous micellar two-phase systems as an integrative methodology to extract, concentrate and purify isoflavones. PMID:27451211

  13. POTENSI MIKROEMULSI β-KAROTEN DALAM MENGHAMBAT FOTOOKSIDASI VITAMIN C SISTEM AQUEOUS [The Potential Inhibition of Β-Carotene Microemulsion on Vitamin C Photooxidation in Aqueous Systems

    Directory of Open Access Journals (Sweden)

    Setyaningrum Ariviani1*

    2011-06-01

    Full Text Available Photooxidation in food system causes nutritional losses and produces undesirable flavor, toxic and color compounds, which make foods unacceptable to consumers. The objective of this research was to determine β–carotene microemulsion inhibitory effect on vitamin C photooxidation in aqueous food model. Into aqueous food models containing vitamin C (450 ppm for model 1; 300 ppm for model 2 2% microemulsion or β–carotene microemulsion and erythrosine as photosensitizer, were added. The final β–carotene content in aqueous food model was equal to 0.6 or 12 ppm. The result indicated that microemulsion have ability to inhibit vitamin C photodegradation under light but did not show the ability under dark condition. The inhibitory effectiveness of both 6 and 12 ppm β-carotene microemulsion on vitamin C photodegradation were insignificant. The 6 ppm β-carotene microemulsion was proven to effectively inhibit vitamin C photooxidation in aqueous food model better than that of empty microemulsion or free β-carotene. The vitamin C photodegradation rate on model system 1 and 2 were 9.5 ± 2.48 and 6.4 ± 1.58 mg.L-1. hour-1 (β-carotene microemulsion; -14.8 ± 1.69 and -9.5 ± 1.23 mg.L-1. hour -1 (empty microemulsion; -16.0 ± 1.64 and -10.3 ± 0.46 mg.L-1. hour -1 (freeβ-carotene, respectively.

  14. Intermolecular interactions and 3D structure in cellulose-NaOH-urea aqueous system.

    Science.gov (United States)

    Jiang, Zhiwei; Fang, Yan; Xiang, Junfeng; Ma, Yanping; Lu, Ang; Kang, Hongliang; Huang, Yong; Guo, Hongxia; Liu, Ruigang; Zhang, Lina

    2014-08-28

    The dissolution of cellulose in NaOH/urea aqueous solution at low temperature is a key finding in cellulose science and technology. In this paper, (15)N and (23)Na NMR experiments were carried out to clarify the intermolecular interactions in cellulose/NaOH/urea aqueous solution. It was found that there are direct interactions between OH(-) anions and amino groups of urea through hydrogen bonds and no direct interaction between urea and cellulose. Moreover, Na(+) ions can interact with both cellulose and urea in an aqueous system. These interactions lead to the formation of cellulose-NaOH-urea-H2O inclusion complexes (ICs). (23)Na relaxation results confirmed that the formation of urea-OH(-) clusters can effectively enhance the stability of Na(+) ions that attracted to cellulose chains. Low temperature can enhance the hydrogen bonding interaction between OH(-) ions and urea and improve the binding ability of the NaOH/urea/H2O clusters that attached to cellulose chains. Cryo-TEM observation confirmed the formation of cellulose-NaOH-urea-H2O ICs, which is in extended conformation with mean diameter of about 3.6 nm and mean length of about 300 nm. Possible 3D structure of the ICs was proposed by the M06-2X/6-31+G(d) theoretical calculation, revealing the O3H···O5 intramolecular hydrogen bonds could remain in the ICs. This work clarified the interactions in cellulose/NaOH/urea aqueous solution and the 3D structure of the cellulose chain in dilute cellulose/NaOH/urea aqueous solution. PMID:25111839

  15. Partitioning Behavior of Papain in Ionic Liquids-Based Aqueous Two-Phase Systems

    OpenAIRE

    Zhiwen Bai; Yanhong Chao; Meiling Zhang; Changri Han; Wenshuai Zhu; Yonghui Chang; Huaming Li; Yang Sun

    2013-01-01

    This paper attempts to study and optimize the affinity partitioning conditions of papain in an aqueous two-phase system (ATPS). The effect of the amount of ionic liquids (ILs), the concentration of K2HPO4, temperature, pH, and the volume of papain solution were discussed concretely. The optimum conditions were determined as ionic liquid was 1.4 g and K2HPO4 was 1.4 g, the extraction efficiency of papain co...

  16. Ruthenium on rutile catalyst, catalytic system, and method for aqueous phase hydrogenations

    Science.gov (United States)

    Elliot, Douglas C.; Werpy, Todd A.; Wang, Yong; Frye, Jr., John G.

    2001-01-01

    An essentially nickel- and rhenium-free catalyst is described comprising ruthenium on a titania support where the titania is greater than 75% rutile. A catalytic system containing a nickel-free catalyst comprising ruthenium on a titania support where the titania is greater than 75% rutile, and a method using this catalyst in the hydrogenation of an organic compound in the aqueous phase is also described.

  17. Microbiologically induced corrosion of aluminum alloys in fuel-oil/aqueous system.

    Science.gov (United States)

    Yang, S S; Lin, J Y; Lin, Y T

    1998-09-01

    To investigate the microbiologically induced corrosion of aluminum alloys in fuel-oil/aqueous system, aluminum alloys A356, AA 5052, AA 5083 and AA 6061 were chosen as the test alloys and Cladosporium and several fuel-oil contaminated microbes isolated in Taiwan were used as test organisms. Aluminum alloy AA 5083 in fuel-oil/aqueous system was the most susceptible material for microbial corrosion, then followed by aluminum alloys AA 5052 and A356, and AA 6061 was more resistant to microbial aggression. Mixed culture had high capability of corrosion, then followed by Penicillium sp. AM-F5, Fusarium sp. AM-F1, Pseudomonas aeruginosa AM-B5, Ps. fluorescens AM-B9, C. resinae ATCC 22712, Penicillium sp. AM-F2, Candida sp. AM-Y1 and Ps. aeruginosa AM-B11. From energy dispersive spectrometer analysis, aluminum and magnesium contents decreased in the corrosion area, while chlorine and sulfur contents increased. The major organic acid produced in fuel-oil/aqueous system was acetic acid, and the total organic acids content had a positive correlation with the degree of microbial corrosion. PMID:10496152

  18. Constructed wetland treatment systems for the remediation of metal- bearing aqueous discharges. Final report

    International Nuclear Information System (INIS)

    Electric utility activities, such as coal mining, processing, and combustion, often produce aqueous (wastewater) discharges containing metals. Chemical treatment of these discharges to achieve compliance with National Pollution Discharge Elimination System (NPDES) requirements can be costly. Constructed wetland treatment systems offer an inexpensive, natural, low-maintenance, and potentially long-term solution for the treatment of aqueous discharges without chemical additives. At the present time, several electric utilities are using constructed wetland treatment systems to achieve NPDES compliance. Constructed wetland treatment systems take advantage of natural biogeochemical processes to treat utility wastewaters, thus meeting NPDES compliance levels in an environmentally effective manner. This report provides information on the natural science, wastewater treatment, and regulatory/jurisdictional aspects of constructed wetland treatment systems used within the electric utility industry. Included is data from a number of electric utility constructed wetland treatment sites. The principal advantages of using constructed wetland systems to treat wastewater are the low overall cost compared to more conventional chemical treatment methods, the simplicity of operation, and the capacity to provide long-term resource recovery. For example, using a lined constructed wetland treatment system with high retention efficiency for heavy metals provides the option of resource recovery at some future date from a discrete volume of wetland material. Contaminants that can be removed with high efficiency in a number of constructed wetland treatment systems include heavy metals, toxic organics, suspended solids, and nutrients. This report discusses the treatability of specific contaminants as well as metal uptake and translocation processes in constructed wetlands

  19. Cytotoxicity of aqueous extracts of Rosmarinus officinalis L. (Labiatae) in plant test system.

    Science.gov (United States)

    Cardoso, G H S; Dantas, E B S; Sousa, F R C; Peron, A P

    2014-11-01

    This study investigated the cytotoxic activity of Rosmarinus officinalis L. (rosemary) aqueous extract on the cell cycle of Allium cepa. To this end, crude aqueous leaf extracts at four concentrations, 0.02, 0.04, 0.06 and 0.08 mg/mL, were tested on A. cepa meristematic root cells, at exposure times of 24 and 48 h. Slides were prepared by the crushing technique, and cells analyzed throughout the cell cycle, totaling 5,000 for each control group and concentration. The four concentrations tested, including the lowest and considered ideal for use, at all exposure times, showed a significant antiproliferative effect on the cell cycle of this test system and presented a high number of cells in prophase. Our results evidenced the cytotoxicity of rosemary extracts, under the studied conditions. PMID:25627599

  20. Overcoming Phase-Transfer Limitations in the Conversion of Lipophilic Oleo Compounds in Aqueous Media-A Thermomorphic Approach.

    Science.gov (United States)

    Gaide, Tom; Dreimann, Jens M; Behr, Arno; Vorholt, Andreas J

    2016-02-01

    A new process concept has been developed for recycling transition-metal catalysts in the synthesis of moderately polar products via aqueous thermomorphic multicomponent solvent systems. This work focuses on the use of "green" solvents (1-butanol and water) in the hydroformylation of the bio-based substrate methyl 10-undecenoate. Following the successful development of a biphasic reaction system on the laboratory scale, the reaction was transferred to a continuously operated miniplant to demonstrate the robustness of this innovative recycling concept for homogenous catalysts. PMID:26822502

  1. Single and Tertiary System Dye Removal from Aqueous Solution Using Bottom Ash: Kinetic and Isotherm Studies

    Directory of Open Access Journals (Sweden)

    R. Gandhimathi

    2012-01-01

    Full Text Available This paper investigates the ability of Bottom ash to adsorb three cationic dyes from aqueous solution in single and tertiary systems. Crystal Violet (CV, Methylene Blue (MB and Malachite Green (MG were used as cationic dye models. The surface characteristics of Bottom ash were investigated using Fourier Transform Infrared (FTIR. Pseudo second order model was fitted better than Pseudo First order model for all system of MG, MB and CV. From the isotherm study, the adsorption capacity increased in the order of MB< MGsystem. It may be concluded that the adsorption capacity of Bottom ash decreases in tertiary system as compared to single system. Langmuir and Freundlich isotherm models were fitted for all system of dyes. Freundlich isotherm model found to be the best fit for all systems.

  2. A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

    Directory of Open Access Journals (Sweden)

    Andrew Bogdan

    2009-04-01

    Full Text Available We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leaving the organic product separate from the aqueous by-products. Furthermore, the microreactor oxidized a wide range of alcohols and remained active in excess of 100 trials without showing any loss of catalytic activity.

  3. Isotope Fractionation of chlorine in Aqueous System: One Study on Anion-Exchange Chromatography.

    Science.gov (United States)

    Musashi, M.; Oi, T.; Eggenkamp, H.; Van Cappellen, P.

    2001-05-01

    Stable chlorine isotopes such as 37Cl and 35Cl have been paid attention as useful tool identifying the source, and monitoring the transport process and natural fate of chlorinated organic pollutants in air and groundwater. However, it is not established yet whether any isotope effects accompany biodegradation or reductive dehalogenation of the pollutants (Clark and Fritz, 1997). Here we first present an experimental determination of isotope fractionation factor of chlorine in aqueous system by using anion-exchange chromatographic technique. Into the Cl-free anion exchange resin (Muromac, OH- form) packed in a 30 cm long pyrex glass column and controlled temperature at 25 oC, hydrochloric solution was fed with controlling the flow rate constant. Effluent from the column was recovered by an automatic fraction collector and prepared for Cl isotope analysis. The Cl isotope ratio (δ 37Cl vs. SMOC) was measured by IR-MS at the Utrecht University with precision of 0.06 per-mil. Magnitude of the factor obtained was 1.00035 at 25 oC. The result indicates that the lighter isotope (35Cl) was preferably fractionated into the resin phase, while the heavier one (37Cl) was enriched into the aqueous phase. This trend suggests that molecular structure of hydrolysis with Cl in aqueous phase may be more stable than that of Cl ionically bonding with the resin. This result may offer physico-chemical insights into behavior and fate of the pollutants.

  4. Biphasic synovial sarcoma in mandibular region

    Directory of Open Access Journals (Sweden)

    Vijay Wadhwan

    2011-01-01

    Full Text Available The term synovioma was coined by Smith in 1927, and later in 1936 Knox suggested the name synovial sarcoma. It occurs primarily in the paraarticular regions, usually in close association with tendon sheaths, bursae, and joint capsules. On rare occasions it may be seen in areas without any apparent relationship to synovial structures as in parapharyngeal region or the abdominal cavity. The first description of synovial sarcoma in the head and neck region was by Pack and Ariel in 1950. The majority of these tumors seem to take origin from paravertebral connective tissue spaces and manifest as solitary retropharyngeal or parapharyngeal masses near the carotid bifurcation. Synovial sarcoma has been reported in soft palate, tongue, maxillofacial region, angle of mandible, sternoclavicular region, scapular region, and the esophagus. We report a case of 28-year-old male patient with synovial sarcoma in mandibular region with biphasic pattern.

  5. Thermo-responsive properties driven by hydrogen bonding in aqueous cationic gemini surfactant systems.

    Science.gov (United States)

    Wei, Xi-Lian; Han, Chuan-Hong; Geng, Pei-Pei; Chen, Xiao-Xiao; Guo, Yan; Liu, Jie; Sun, De-Zhi; Zhang, Jun-Hong; Yu, Meng-Jiao

    2016-02-01

    A series of unexpected thermo-responsive phenomena were discovered in an aqueous solution of the cationic gemini surfactant, 2-hydroxypropyl-1,3-bis(alkyldimethylammonium chloride) (n-3(OH)-n(2Cl), n = 14, 16), in the presence of an inorganic salt. The viscosity change trend for the 14-3(OH)-14(2Cl) system was investigated in the 20-40 °C temperature range. As the temperature increased, the viscosity of the solution first decreased to a minimum point corresponding to 27 °C, and then increased until a maximum was reached, after which the viscosity decreased again. In the 16-3(OH)-16(2Cl) system, the gelling temperature (T(gel)) and viscosity changes upon heating were similar to those in the 14-3(OH)-14(2Cl) system above 27 °C. The reversible conversion of elastic hydrogel to wormlike micelles in the aqueous solution of the 16-3(OH)-16(2Cl) system in the presence of an inorganic salt was observed at relatively low temperatures. Various techniques were used to study and verify the phase-transition processes in these systems, including rheological measurements, cryogenic transmission electron microscopy (cryo-TEM), electric conductivity, and differential scanning calorimetry. The abovementioned phenomena were explained by the formation and destruction of intermolecular hydrogen bonds, and the transition mechanisms of the aggregates were analyzed accordingly. PMID:26659081

  6. Operation and Performance of a Biphase Turbine Power Plant at the Cerro Prieto Geothermal Field (Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Lance G. [Douglas Energy Company, Placentia, CA (United States)

    2000-09-01

    % after implementations of this method in March 2000. However, failures of instrumentation and control system components led to additional plant down time and damage to the bearings and seals. The enthalpy and pressure of well 103 declined substantially from the inception of the project. When the project was started the wellhead pressure and enthalpy were 760 psig and 882 Btu/lb respectively. At the time the plant was placed in standby the corresponding values were only 525 psig and 658 Btu/lb. This reduced the available plant power to only 400 kWe making the project economically unfeasible. However, replacement of the existing rotor with the Dual Pressure Rotor and replacement of the bearings and seals will enable the existing Biphase turbine to produce 1190 kWe at the present well conditions without the backpressure steam turbine. Operation with the present staff can then be sustained by selling power under the existing Agreement with CFE. Implementation of this option is recommended with operation of the facility to continue as a demonstration plant. Biphase turbine theory, design and performance are reported herein. The construction of the Biphase turbine and power plant and operational experience are detailed. Improvements in the Biphase turbine are indicated and analyzed. The impact of Biphase techonology on geothermal power production is discussed and recommendations made.

  7. Rapid RNA Exchange in Aqueous Two-Phase System and Coacervate Droplets

    Science.gov (United States)

    Jia, Tony Z.; Hentrich, Christian; Szostak, Jack W.

    2014-02-01

    Compartmentalization in a prebiotic setting is an important aspect of early cell formation and is crucial for the development of an artificial protocell system that effectively couples genotype and phenotype. Aqueous two-phase systems (ATPSs) and complex coacervates are phase separation phenomena that lead to the selective partitioning of biomolecules and have recently been proposed as membrane-free protocell models. We show in this study through fluorescence recovery after photobleaching (FRAP) microscopy that despite the ability of such systems to effectively concentrate RNA, there is a high rate of RNA exchange between phases in dextran/polyethylene glycol ATPS and ATP/poly-L-lysine coacervate droplets. In contrast to fatty acid vesicles, these systems would not allow effective segregation and consequent evolution of RNA, thus rendering these systems ineffective as model protocells.

  8. Comparison of capacitive behavior of activated carbons with different pore structures in aqueous and nonaqueous systems

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shao-yun; LI Xin-hai; WANG Zhi-xing; GUO Hua-jun; PENG Wen-jie

    2008-01-01

    The pore structures of two activated carbons from sawdust with KOH activation and coconut-shell with steam activation for supercapacitor were analyzed by N2 adsorption method. The electrochemical properties of both activated carbons in 6mol/L KOH solution and 1mol/L Et4NPF4/PC were compared, and the effect of pore structure on the capacitance was investigated by cyclic voltammetry, AC impedance and charge-discharge measurements. The results indicate that the capacitance mainly depends on effective surface area, but the power property mainly depends on mesoporosity. At low specific current (1A/g), the maximum specific capacitances of 276.3F/g in aqueous system and 123.9F/g in nonaqueous system can be obtained from sawdust activated carbon with a larger surface area of 1808m2/g, but at a high specific current, the specific capacitance of coconut-shell activated carbon with a higher mesoporosity of 75.1% is more excellent. Activated carbon by KOH activation is fitter for aqueous system and that by steam activation is fitter for nonaqueous system.

  9. Optimization of Biosorptive Removal of Dye from Aqueous System by Cone Shell of Calabrian Pine

    OpenAIRE

    Fatih Deniz

    2014-01-01

    The biosorption performance of raw cone shell of Calabrian pine for C.I. Basic Red 46 as a model azo dye from aqueous system was optimized using Taguchi experimental design methodology. L9 (33) orthogonal array was used to optimize the dye biosorption by the pine cone shell. The selected factors and their levels were biosorbent particle size, dye concentration, and contact time. The predicted dye biosorption capacity for the pine cone shell from Taguchi design was obtained as 71.770 mg g−1 un...

  10. Comparison of colorimetric methods for the quantification of model proteins in aqueous two-phase systems.

    Science.gov (United States)

    Glyk, Anna; Heinisch, Sandra L; Scheper, Thomas; Beutel, Sascha

    2015-05-15

    In the current study, the quantification of different model proteins in the presence of typical aqueous two-phase system components was investigated by using the Bradford and bicinchoninic acid (BCA) assays. Each phase-forming component above 1 and 5 wt% had considerable effects on the protein quantification in both assays, respectively, resulting in diminished protein recoveries/absorption values by increasing poly(ethylene glycol) (PEG)/salt concentration and PEG molecular weight. Therefore, a convenient dilution of both components (up to 1 and 5 wt%) before protein quantification is recommended in both assays, respectively, where the BCA assay is favored in comparison with the Bradford assay. PMID:25684109

  11. Purification and In Situ Immobilization of Papain with Aqueous Two-Phase System

    OpenAIRE

    Li, Mingliang; Su, Erzheng; You, Pengyong; Gong, Xiangyu; Sun, Ming; Xu, Diansheng; Wei, Dongzhi

    2010-01-01

    Papain was purified from spray-dried Carica papaya latex using aqueous two-phase system (ATPS). Then it was recovered from PEG phase by in situ immobilization or preparing cross-linked enzyme aggregates (CLEAs). The Plackett-Burman design and the central composite design (CCD) together with the response surface methodology (RSM) were used to optimize the APTS processes. The highly purified papain (96–100%) was achieved under the optimized conditions: 40% (w/w) 15 mg/ml enzyme solution, 14.33–...

  12. The interaction between oxytetracycline and divalent metal ions in aqueous and mixed solvent systems.

    Science.gov (United States)

    Tongaree, S; Flanagan, D R; Poust, R I

    1999-01-01

    The effects of pH, mixed solvent systems, and divalent metal ions on oxytetracycline (OTC) solubility and the interactions between OTC and metal ions in aqueous and mixed solvent systems were investigated. OTC solubility profiles were obtained for pH 4-9. The cosolvents studied were glycerin, propylene glycol, PEG 400, and 2-pyrrolidone with the following metal ions: magnesium, calcium, and zinc. OTC and its interactions with these metal ions were evaluated by solubility, NMR, circular dichroism (CD), and electron diffraction (ED) methods. At pH 5.6, no complexation occurred with these metal ions, but OTC zwitterion formed aggregates in aqueous solutions as shown by NMR spectra. The hydration of the metal ions was observed to affect OTC aggregation, with Mg+2 causing the greatest OTC aggregation. At pH 7.5, OTC aggregation and metal-OTC complexation were observed in solutions with Ca+2 and Mg+2. Zinc ion was found to decrease OTC solubility because of zincate formation, which caused anionic OTC to precipitate. Electron diffraction revealed a relationship between OTC and metal-OTC complex crystallinity and solubility behavior. The zinc-OTC complex exhibited the highest crystallinity and lowest solubility at pH 8.0. Various cosolvents generally enhanced OTC solubility, with 2-pyrrolidone having the best solubility power. In OTC-metal-2-pyrrolidone and OTC-Zn(+2)-PEG 400 systems, circular dichroism provided evidence for the formation of soluble ternary complexes. PMID:10578513

  13. Bifunctional polyacrylonitrile fiber-mediated conversion of sucrose to 5-hydroxymethylfurfural in mixed-aqueous systems.

    Science.gov (United States)

    Shi, Xian-Lei; Zhang, Min; Lin, Huikun; Tao, Minli; Li, Yongdan; Zhang, Wenqin

    2015-03-01

    A highly efficient catalytic system composed of a bifunctional polyacrylonitrile fiber (PANF-PA[BnBr]) and a metal chloride was employed to produce 5-hydroxymethylfurfural (HMF) from sucrose in mixed-aqueous systems. The promoter of PANF-PA[BnBr] incorporates protonic acid groups that promote the hydrolysis of the glycosidic bond to convert sucrose into glucose and fructose, and then catalyzes fructose dehydration to HMF, while the ammonium moiety may promote synergetically with the metal chloride the isomerization of glucose to fructose and transfer HMF from the aqueous to the organic phase. The detailed characterization by elemental analysis, FTIR spectroscopy, and SEM confirmed the rangeability of the fiber promoter during the modification and utilization processes. Excellent results in terms of high yield (72.8%) of HMF, superior recyclability (6 cycles) of the process, and effective scale-up and simple separation procedures of the catalytic system were obtained. Moreover, the prominent features (high strength, good flexibility, etc.) of the fibers are very attractive for fix-bed reactor. PMID:25573698

  14. On-chip aqueous two-phase system (ATPS) formation, consequential self-mixing, and their influence on drop-to-drop aqueous two-phase extraction kinetics

    Science.gov (United States)

    Wijethunga, Pavithra A. L.; Moon, Hyejin

    2015-09-01

    Aqueous two-phase systems (ATPSs) allow an advantageous aqueous two-phase extraction process (ATPE), a special type of liquid-liquid extraction. Compared with conventional liquid-liquid extraction using aqueous/organic extraction media, ATPE is known to provide relatively easy mass transfer and a gentle environment for biological separation applications. Considering the recent interest in microscale ATPE, we aimed to study (i) the potential of preparing ATPS droplets on a digital microfluidic device, and (ii) the influence of the fluidic dynamics created during the formation of ATPS, with the goal of enhancing on-chip ATPE process. On-chip ATPS formation was evaluated by preparing a series of ATPSs on electrowetting on dielectric digital microfluidic chips and comparing their characteristics with the same ATPSs prepared at macroscale using conventional procedures. An enhanced on-chip drop-to-drop ATPE process was achieved by incorporating a self-mixing condition created during ATPSformation. Results indicate a successful on-chip ATPS preparation as well as enhanced extraction performance by self-mixing in the absence of forced mixing. Findings of this research suggest an alternative, simple, yet adequate technique to provide mixing for on-chip applications, such as sample preparation in portable microfluidics, for which it is unfavorable to implement complicated mixing sequences or complex device geometries.

  15. Effect of bentonite on radiation induced dissolution of UO{sub 2} in an aqueous system

    Energy Technology Data Exchange (ETDEWEB)

    Barreiro Fidalgo, Alexandre, E-mail: alebf@kth.se; Sundin, Sara, E-mail: saramara@kth.se; Jonsson, Mats, E-mail: matsj@kth.se

    2014-04-01

    In order to elucidate the impact of bentonite on the process of radiation induced oxidative dissolution of UO{sub 2} in an aqueous system, the dissolution of U(VI) and consumption of H{sub 2}O{sub 2} over time has been studied. In addition, γ-irradiation experiments were performed to study a more relevant and complex system, serving as a comparison with the previously stated system. In both cases, the experiments revealed that the presence of bentonite in water could either delay or prevent in part the release of uranium to the environment. The cause is mainly attributed to the scavenging of radiolytic oxidants rather than to the adsorption of uranium onto bentonite.

  16. Radiation-chemical behavior of uranium and plutonium in heterogeneous MeO2-aqueous solution systems

    International Nuclear Information System (INIS)

    The paper studies radiation-chemical behavior of U and Pu in heterogeneous UO2-aqueous mellitate systems and the PuO2-groundwater systems, respectively. It is found that U(IV) passes into the aqueous phase in the irradiated system and oxidizes further to U(VI) while Pu(IV) solubilizes both in irradiated and unirradiated groundwater and then goes to Pu(V) and Pu(III). The latter processes is more powerful in irradiated solutions. The radiation-chemical behavior of U and Pu in the systems under study is interpreted on the strength of spectrophotometric characteristics of irradiated and unirradiated solutions. (author)

  17. Oxidation and mobilization of metallic antimony in aqueous systems with simulated groundwater

    Science.gov (United States)

    Ilgen, A. G.; Majs, F.; Barker, A. J.; Douglas, T. A.; Trainor, T. P.

    2014-05-01

    Antimony (Sb) is a contaminant of concern that can be present in elevated concentrations in shooting range soils due to mobilization from spent lead/antimony bullets. Antimony in shooting range soils has been observed as either metallic Sb(0) or as Sb(V) immobilized by iron (hydr)oxides. The absence of Sb(III) in soils is indicative of rapid Sb(III) oxidation to Sb(V) under surface soil conditions. However, the major controls on antimony oxidation and mobility are poorly understood. To better understand these controls we performed multiple batch experiments under oxic conditions to quantify the oxidation and dissolution of antimony in systems where Sb(0) is oxidized to Sb(III) and further to Sb(V). We also tested how variations in the aqueous matrix composition and the presence of metallic lead (Pb) affect the dissolution, solid phase speciation, and oxidation of antimony. We monitored changes in the aqueous antimony speciation using liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS). To test which solid phases form as a result of Sb(0) oxidation, and therefore potentially limit the mobility of antimony in our studied systems, we characterized the partially oxidized Sb(0) powders by means of extended X-ray absorption fine structure (EXAFS) spectroscopy and powder X-ray diffraction (XRD).

  18. Molar heat capacities of some aqueous (2-amino-2-hydroxymethyl-1,3-propanediol + glycol) systems

    International Nuclear Information System (INIS)

    Highlights: ► The molar heat capacities for several aqueous (2-amino-2-hydroxymethyl-1,3-propanediol + glycol) systems were measured. ► The glycols considered were ethylene glycols and propylene glycols. ► The temperature studied was (30 to 70) °C. ► The measured data were reported as functions of temperature and composition. ► The measured data were represented satisfactorily by the applied correlations. - Abstract: A new set of molar heat capacity data for aqueous {2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) + glycol} at (30 to 80) °C and different concentrations (4% to 16% by weight TRIS or 56% to 44% by weight water, in a fixed amount of glycol – 40% by weight) were gathered via reliable measurement method and are presented in this report. The glycols considered were diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (T4EG), propylene glycol (PG), dipropylene glycol (DPG), and tripropylene glycol (TPG). The 198 data points gathered fit the equation, Cp = Cp,a + B1m + B2m2 + B3m3, where Cp and Cp,a are the molar heat capacities of the (TRIS + glycol + water) and (water + glycol) systems, respectively, Bi the temperature-dependent parameters, and m the mole TRIS per kilogram (glycol + water). The overall average absolute deviation (AAD) of the experimental data from the corresponding values calculated from the correlation equation was 0.07%.

  19. Phase Separation Behavior and System Properties of Aqueous Two-Phase Systems with Polyethylene Glycol and Different Salts: Experiment and Correlation

    OpenAIRE

    Haihua Yuan; Yang Liu; Wanqian Wei; Yongjie Zhao

    2015-01-01

    The phase separation behaviors of PEG1000/sodium citrate, PEG4000/sodium citrate, PEG1000/ammonium sulfate, and PEG4000/ammonium sulfate aqueous two-phase systems were investigated, respectively. There are two distinct situations for the phase separation rate in the investigated aqueous two-phase systems: one state is top-continuous phase with slow phase separation rate and strong bottom-continuous phase with fast phase separation rate and weak volume ratio dependence. The system properties s...

  20. Biphasic Janus particles with nanoscale anisotropy

    Science.gov (United States)

    Roh, Kyung-Ho; Martin, David C.; Lahann, Joerg

    2005-10-01

    Advances in the field of nanotechnology have fuelled the vision of future devices spawned from tiny functional components that are able to assemble according to a master blueprint. In this concept, the controlled distribution of matter or `patchiness' is important for creating anisotropic building blocks and introduces an extra design parameter - beyond size and shape. Although the reliable and efficient fabrication of building blocks with controllable material distributions will be of interest for many applications in research and technology, their synthesis has been addressed only in a few specialized cases. Here we show the design and synthesis of polymer-based particles with two distinct phases. The biphasic geometry of these Janus particles is induced by the simultaneous electrohydrodynamic jetting of parallel polymer solutions under the influence of an electrical field. The individual phases can be independently loaded with biomolecules or selectively modified with model ligands, as confirmed by confocal microscopy and transmission electron microscopy. The fact that the spatial distribution of matter can be controlled at such small length scales will provide access to unknown anisotropic materials. This type of nanocolloid may enable the design of multicomponent carriers for drug delivery, molecular imaging or guided self-assembly.

  1. Selective separation and enrichment of proteins in aqueous two-phase extraction system

    Institute of Scientific and Technical Information of China (English)

    Feng Qu; Hao Qin; Min Dong; Dong Xu Zhao; Xin Ying Zhao; Jing Hua Zhang

    2009-01-01

    A simple aqueous two-phase extraction system(ATPS)of PEG/phosphate was proposed for selective separation and enrichment of proteins.The combination of ATPE with HPLC was applied to identify the partition of proteins in two phases.Five proteins (bovine serum albumin,Cytochrome C,lysozyme,myoglobin,and trypsin)were used as model proteins to study the effect of phosphate concentration and pH on proteins partition.The PEG/phosphate system was firstly applied to real human saliva and plasma samples,some proteins showed obviously different partition in two phases.The primary results manifest the selective separation and enrichment of proteins in ATPS provided the potential for high abundance proteins depletion in proteomics.

  2. Dynamics of macroscopic fluctuations in aqueous systems according to Rayleigh scattering data

    Science.gov (United States)

    Belovolova, L. V.; Glushkov, M. V.; Timashev, S. F.

    2015-09-01

    The general question of the existence of macrofluctuations of physical characteristics of aqueous systems are discussed. Using the example of analyzing fluctuations in the Rayleigh scattering of natural untreated water, along with catholyte and anolyte obtained in its electrochemical treatment, the possibility of obtaining of quantitative information on the states and dynamics of changes in such systems is shown. Data on the parameters of oscillations in the Rayleigh light scattering of water catholyte and anolyte immediately after electrolysis, and one and two days after its completion, are presented. Calculations are performed using the general phenomenological approach to analyzing chaotic signals (flicker-noise spectroscopy). Quantitative characteristics that reveal substantial differences in the dynamics of macrofluctuations that develop in the catholyte and anolyte of the studied water are presented.

  3. Pseudo-biphasic extraction and liquid membrane transport of ionic solutes using micelle-based processes

    International Nuclear Information System (INIS)

    Different aspects between micellar extraction and solvent extraction were discussed. One way of using micellar systems to perform metal ion extraction consists in solubilizing lipophilic complexing agents in the hydrophobic core of the micelles, similarly to their solubilization in the organic phase in classical biphasic extraction. Metal ions dissolved in the continuous phase will be complexed or not, depending on their affinity for the micelle-solubilized extractant, the microscopic micelle/water interface playing a part analogous to the macroscopic organic/water interface in biphasic extraction. The yields of extraction (after ultrafiltration of the micellar pseudo-phase) when parameters such as the extractant/metal ratio or the extractant hydrophobicity are changed, show similar trends as those reported in the case of solvent extraction, but only diluted solutions can be treated that way. 14 refs

  4. Design and In Vitro Evaluation of a New Nano-Microparticulate System for Enhanced Aqueous-Phase Solubility of Curcumin

    Directory of Open Access Journals (Sweden)

    Diana Guzman-Villanueva

    2013-01-01

    Full Text Available Curcumin, a yellow polyphenol derived from the turmeric Curcuma longa, has been associated with a diverse therapeutic potential including anti-inflammatory, antioxidant, antiviral, and anticancer properties. However, the poor aqueous solubility and low bioavailability of curcumin have limited its potential when administrated orally. In this study, curcumin was encapsulated in a series of novel nano-microparticulate systems developed to improve its aqueous solubility and stability. The nano-microparticulate systems are based entirely on biocompatible, biodegradable, and edible polymers including chitosan, alginate, and carrageenan. The particles were synthesized via ionotropic gelation. Encapsulating the curcumin into the hydrogel nanoparticles yielded a homogenous curcumin dispersion in aqueous solution compared to the free form of curcumin. Also, the in vitro release profile showed up to 95% release of curcumin from the developed nano-microparticulate systems after 9 hours in PBS at pH 7.4 when freeze-dried particles were used.

  5. Influence factors for the oxidation of pyrite by oxygen and birnessite in aqueous systems.

    Science.gov (United States)

    Qiu, Guohong; Luo, Yao; Chen, Cheng; Lv, Qiang; Tan, Wenfeng; Liu, Fan; Liu, Chengshuai

    2016-07-01

    The oxidation of exposed pyrite causes acid mine drainage, soil acidification, and the release of toxic metal ions. As the important abiotic oxidants in supergene environments, oxygen and manganese oxides participate in the oxidation of pyrite. In this work, the oxidation processes of natural pyrite by oxygen and birnessite were studied in simulated systems, and the influence of pH, Fe(II) and Cr(III) on the intermediates and redox rate was investigated. SO4(2-) and elemental S were formed as the major and minor products, respectively, during the oxidation processes. Ferric (hydr) oxides including Fe(OH)3 and goethite were formed with low degree of crystallinity. Low pH and long-term reaction facilitated the formation of goethite and ferric hydroxide, respectively. The rate of pyrite oxidation by birnessite was enhanced in the presence of air (oxygen), and Fe(II) ions played a key role in the redox process. The addition of Fe(II) ions to the reaction system significantly enhanced the oxidation rate of pyrite; however, the presence of Cr(III) ions remarkably decreased the pyrite oxidation rate in aqueous systems. The introduction of Fe(II) ions to form a Fe(III)/Fe(II) redox couple facilitated the electron transfer and accelerated the oxidation rate of pyrite. The present work suggests that isolation from air and decreasing the concentration of Fe(II) ions in aqueous solutions might be effective strategies to reduce the oxidation rate of pyrite in mining soils. PMID:27372130

  6. Electrochemiluminescence of terbium (III)-two fluoroquinolones-sodium sulfite system in aqueous solution

    Science.gov (United States)

    Chen, Shi-lv; Ding, Fen; Liu, Yu; Zhao, Hui-chun

    2006-05-01

    The electrochemiluminescence (ECL) of Tb 3+-enoxacin-Na 2SO 3 system (ENX system) and Tb 3+-ofloxacin-Na 2SO 3 system (OFLX system) in aqueous solution is reported. ECL is generated by the oxidation of Na 2SO 3, which is enhanced by Tb 3+-fluoroquinolone (FQ) complex. The ECL intensity peak versus potential corresponds to oxidation of Na 2SO 3, and the ECL emission spectra (the peaks are at 490, 545, 585 and 620 nm) match the characteristic emission spectrum of Tb 3+, indicating that the emission is from the excited state of Tb 3+. The mechanism of ECL is proposed and the difference of ECL intensity between ENX system and OFLX system is explained. Conditions for ECL emission were optimized. The linear range of ECL intensity versus concentrations of pharmaceuticals is 2.0 × 10 -10-8.0 × 10 -7 mol l -1 for ENX and 6.0 × 10 -10-6.0 × 10 -7 mol l -1 for OFLX, respectively. A theoretical limit of detection is 5.4 × 10 -11 mol l -1 for ENX and 1.6 × 10 -10 mol l -1 for OFLX, respectively. The ECL was satisfactorily applied to the determination of the two FQs in dosage form and urine sample.

  7. Stoichiometric implications of a biphasic life cycle.

    Science.gov (United States)

    Tiegs, Scott D; Berven, Keith A; Carmack, Douglas J; Capps, Krista A

    2016-03-01

    Animals mediate flows of elements and energy in ecosystems through processes such as nutrient sequestration in body tissues, and mineralization through excretion. For taxa with biphasic life cycles, the dramatic shifts in anatomy and physiology that occur during ontogeny are expected to be accompanied by changes in body and excreta stoichiometry, but remain little-explored, especially in vertebrates. Here we tested stoichiometric hypotheses related to the bodies and excreta of the wood frog (Lithobates sylvaticus) across life stages and during larval development. Per-capita rates of nitrogen (N) and phosphorus (P) excretion varied widely during larval ontogeny, followed unimodal patterns, and peaked midway through development (Taylor-Kollros stages XV and XII, respectively). Larval mass did not increase steadily during development but peaked at stage XVII and declined until the termination of the experiment at stage XXII. Mass-specific N and P excretion rates of the larvae decreased exponentially during development. When coupled with population-biomass estimates, population-level excretion rates were greatest at stages VIII-X. Percent carbon (C), N, and C:N of body tissue showed weak trends across major life stages; body P and C:P, however, increased sixfold during development from egg to adult. Our results demonstrate that intraspecific ontogenic changes in nutrient contents of excretion and body tissues can be significant, and that N and P are not always excreted proportionally throughout life cycles. These results highlight the dynamic roles that species play in ecosystems, and how the morphological and physiological changes that accompany ontogeny can influence ecosystem-level processes. PMID:26589522

  8. Characterization of adsorption of aqueous arsenite and arsenate onto charred dolomite in microcolumn systems.

    Science.gov (United States)

    Salameh, Yousef; Al-Muhtaseb, Ala'a H; Mousa, Hasan; Walker, Gavin M; Ahmad, Mohammad N M

    2014-01-01

    In this work, the removal of arsenite, As(III), and arsenate, As(V), from aqueous solutions onto thermally processed dolomite (charred dolomite) via microcolumn was evaluated. The effects of mass of adsorbent (0.5-2 g), initial arsenic concentration (50-2000 ppb) and particle size (dolomite in a microcolumn were investigated. It was found that the adsorption of As(V) and As(III) onto charred dolomite exhibited a characteristic 'S' shape. The adsorption capacity increased as the initial arsenic concentration increased. A slow decrease in the column adsorption capacity was noted as the particle size increased from>0.335 to 0.710-2.00 mm. For the binary system, the experimental data show that the adsorption of As(V) and As(III) was independent of both ions in solution. The experimental data obtained from the adsorption process were successfully correlated with the Thomas Model and Bed Depth Service Time Model. PMID:25244130

  9. Removal of uranium from drinking water and other aqueous systems using modified powdered activated carbon

    International Nuclear Information System (INIS)

    A simple, rapid and eco friendly method for removal of high concentration of Uranium (U) from ground water (>2500 ppb), Mine water(>1000 ppb) and other aqueous systems has been developed based on laboratory trials using 10 litres of mine water and ground water. The removal of uranium was greater than 95% with a contact time of 10 minutes with modified powdered activated carbon (MPAC) at the natural pH of water. The concentration of Uranium left behind in drinking water after MPAC treatment (if necessary twice) was less than 15 ppb and is below WHO/AERB permissible limits. The methodology is so simple that it could be applied at remote villages to produce uranium free drinking water at the natural pH of water

  10. Table 5.1. Exchange current densities and rate constants in aqueous systems

    Science.gov (United States)

    Holze, R.

    This document is part of Volume 9 `Electrochemistry', Subvolume A, of Landolt-Börnstein - Group IV `Physical Chemistry'. This document lists the exchange current densities and the electrode reaction rate constants of the following metallic electrodes in aqueous systems for various electrolyte reactions: silver (Ag), aluminium (Al), gold (Au), bismuth (Bi), carbon (C), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), iron (Fe), gallium (Ga), mercury (Hg), indium (In), iridium (Ir), potassium (K), lithium (Li), molybdenum (Mo), natrium (Na), niobium (Nb), nickel (Ni), lead (Pb), palladium (Pd), platinum (Pt), rubidium (Rb), rhodium (Rh), ruthenium (Ru), antimony (Sb), tin (Sn), tantalum (Ta), titanium (Ti), thallium (Tl), vanadium (V), tungsten (W), zinc (Zn). For each electrolyte reaction the electrolyte solution, the educt, product and concentration are specified along with the temperature of determination of the given values.

  11. Protein partitioning in poly(ethylene glycol)/sodium polyacrylate aqueous two-phase systems.

    Science.gov (United States)

    Johansson, Hans-Olof; Magaldi, Flavio Musa; Feitosa, Eloi; Pessoa, Adalberto

    2008-01-18

    The partition of hemoglobin, lysozyme and glucose-6-phosphate dehydrogenase (G6PDH) in a novel inexpensive aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The effect of NaCl and Na(2)SO(4), pH and PEG molecular size on the partitioning has been studied. At high pH (above 9), hemoglobin partitions strongly to the PEG-phase. Although some precipitation of hemoglobin occurs, high recovery values are obtained particularly for lysozyme and G6PDH. The partitioning forces are dominated by the hydrophobic and electrochemical (salt) effects, since the positively charged lysozyme and negatively charged G6PDH partitions to the non-charged PEG and the strongly negatively charged polyacrylate enriched phase, respectively. PMID:18078945

  12. A green deep eutectic solvent-based aqueous two-phase system for protein extracting

    International Nuclear Information System (INIS)

    Highlights: • A strategy for the protein purification with a deep eutectic solvent(DES)-based aqueous two-phase system. • Choline chloride-glycerin DES was selected as the extraction solvent. • Bovine serum albumin and trypsin were used as the analytes. • Aggregation phenomenon was detected in the mechanism research. - Abstract: As a new type of green solvent, deep eutectic solvent (DES) has been applied for the extraction of proteins with an aqueous two-phase system (ATPS) in this work. Four kinds of choline chloride (ChCl)-based DESs were synthesized to extract bovine serum albumin (BSA), and ChCl-glycerol was selected as the suitable extraction solvent. Single factor experiments have been done to investigate the effects of the extraction process, including the amount of DES, the concentration of salt, the mass of protein, the shaking time, the temperature and PH value. Experimental results show 98.16% of the BSA could be extracted into the DES-rich phase in a single-step extraction under the optimized conditions. A high extraction efficiency of 94.36% was achieved, while the conditions were applied to the extraction of trypsin (Try). Precision, repeatability and stability experiments were studied and the relative standard deviations (RSD) of the extraction efficiency were 0.4246% (n = 3), 1.6057% (n = 3) and 1.6132% (n = 3), respectively. Conformation of BSA was not changed during the extraction process according to the investigation of UV–vis spectra, FT-IR spectra and CD spectra of BSA. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to explore the mechanism of the extraction. It turned out that the formation of DES–protein aggregates play a significant role in the separation process. All the results suggest that ChCl-based DES-ATPS are supposed to have the potential to provide new possibilities in the separation of proteins

  13. A green deep eutectic solvent-based aqueous two-phase system for protein extracting

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Kaijia; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Huang, Yanhua; Li, Na; Wen, Qian

    2015-03-15

    Highlights: • A strategy for the protein purification with a deep eutectic solvent(DES)-based aqueous two-phase system. • Choline chloride-glycerin DES was selected as the extraction solvent. • Bovine serum albumin and trypsin were used as the analytes. • Aggregation phenomenon was detected in the mechanism research. - Abstract: As a new type of green solvent, deep eutectic solvent (DES) has been applied for the extraction of proteins with an aqueous two-phase system (ATPS) in this work. Four kinds of choline chloride (ChCl)-based DESs were synthesized to extract bovine serum albumin (BSA), and ChCl-glycerol was selected as the suitable extraction solvent. Single factor experiments have been done to investigate the effects of the extraction process, including the amount of DES, the concentration of salt, the mass of protein, the shaking time, the temperature and PH value. Experimental results show 98.16% of the BSA could be extracted into the DES-rich phase in a single-step extraction under the optimized conditions. A high extraction efficiency of 94.36% was achieved, while the conditions were applied to the extraction of trypsin (Try). Precision, repeatability and stability experiments were studied and the relative standard deviations (RSD) of the extraction efficiency were 0.4246% (n = 3), 1.6057% (n = 3) and 1.6132% (n = 3), respectively. Conformation of BSA was not changed during the extraction process according to the investigation of UV–vis spectra, FT-IR spectra and CD spectra of BSA. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to explore the mechanism of the extraction. It turned out that the formation of DES–protein aggregates play a significant role in the separation process. All the results suggest that ChCl-based DES-ATPS are supposed to have the potential to provide new possibilities in the separation of proteins.

  14. The effect of sulphates on partitioning of pectinases in aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    Antov Mirjana G.

    2004-01-01

    Full Text Available The effect of various sulphate salts on the partitioning of endo-pectinase and exo-pectinase in aqueous two-phase systems, composed of polyethylene glycol and dextran, was studied. Presence of ammonium sulphate and sodium sulphate at concentration 15 mmol/l in the system polyethylene glycol 4000/crude dextran, at tie-line length 7.44%, increased partition coefficient of endo-pectinase 1.25 and 1.2 fold, respectively. Ammonium sulphate at 15 mmol/l and sodium sulphate at 5 mmol/l enhanced partition coefficient for exo-pectinase for about 60% in comparison to the system without salts. Addition of magnesium and sodium sulphate to a final concentration of 0.3 mmol/l in the system containing polyethylene glycol 6000/dextran 500 000, at tie-line length 6.26%, increased the partition coefficient of endo activity for 95% and 32%, respectively. Both salts at the same concentration increased partition coefficient of exo activity 1.5 and 3 times, respectively, in comparison to the system without salts.

  15. Electrocatalytic oxidation of alcohols and diols in a biphasic medium using CeIV methanesulfonate as mediator

    International Nuclear Information System (INIS)

    Some alcohols and diols were oxidized electro-catalytically in a biphasic system using cerium methanesulphonate as mediator. A mixture of methanesulphonic acid solution and benzene was used and aldehydes, ketones and diacids were some of the principal products obtained with yield varying from 27 to 98%. In several cases selectivity was obtained. (author)

  16. Perfluorinated quaternary ammonium salts of polyoxometalate anions: Fluorous biphasic oxidation catalysis with and without fluorous solvents

    Energy Technology Data Exchange (ETDEWEB)

    Maayan, Galia; Fish, Richard H.; Neumann, Ronny

    2003-05-28

    Perfluorinated quaternary ammonium cations, [CF{sub 3}(CF{sub 2}){sub 7}(CH{sub 2}){sub 3}]{sub 3}CH{sub 3}N{sup +} (RFN{sup +}), were synthesized and used as counter cations for the [WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW{sub 9}O{sub 34}){sub 2}]{sup 12-} (M = Mn(II), Zn(II)), polyoxometalate. The (RFN{sup +}){sub 12}[WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW9O{sub 34}){sub 2}] compounds were fluorous biphasic catalysts for alcohol and alkenol oxidation, and alkene epoxidation with aqueous hydrogen peroxide. Reaction protocols with or without a fluorous solvent were tested. The catalytic activity and selectivity was affected both by the hydrophobicity of the solvent and the substrate.

  17. Obtaining of ceramics biphasic dense and porous; Obtencao de ceramicas bifasicas densas e porosas

    Energy Technology Data Exchange (ETDEWEB)

    Pallone, E.M.J.A.; Rigo, E.C.S., E-mail: eliria@usp.b [Universidade de Sao Paulo (FZEA/USP), Pirassununga, SP (Brazil). Dept. de Ciencias Basicas; Silva, K.L. [Universidade Estadual de Campinas (FEM/UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica; Rezende, M.E. [Universidade Sao Francisco, Itatiba, SP (Brazil); Fraga, A.F. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Marques, R.F.C. [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil)

    2010-07-01

    Among the bioceramic hydroxyapatite (HAP) and beta-tricalcium phosphate (beta-TCP) are materials commonly used in biomedical field. Their combined properties result in a material with absorbable and at the same time with bioactive surface. Called biphasic ceramics such materials respond more quickly when exposed to physiological environment. In this work, powders of HAP/beta-TCP were obtained by chemical precipitation. After obtaining the post-phase was added at a ratio of 0, 15% and 30w% aqueous solutions of corn starch in order to obtain porous bodies. After mixing the resulting solutions were dried, resigned in tablet form and sintered at 1300 deg C. The initial powder was characterized by X-ray diffraction with Rietveld refinement to quantify the phases present. Bodies-of-evidence has been characterized by calculating the bulk density, X-ray diffraction (XRD), scanning electron microscopy and diametral compression. (author)

  18. Combine Studies Pertaining to the Solubility of Neptunium in Oxidizing Aqueous Systems

    International Nuclear Information System (INIS)

    The report combines two separate studies dealing with different aspects of the behavior of neptunium in oxidizing aqueous systems. The goal of both studies is to obtain a better understanding of what would control the concentration of neptunium in oxidizing groundwaters upon release from a geologic high-level waste repository. 237Np has a very long half-life, and consequently tends to appear as a component of concern in long-term dose calculations. Part A examines the formation of NpO2 [Np(IV) oxide] from aqueous Np(V) under oxidizing conditions, using elevated temperature as a means of accelerating putative slow kinetics. According to thermodynamic data, NpO2 should be the stable Np solid, even though Np is generally thought to be mainly some form of Np(V) under oxidizing conditions. The first observed precipitation of this solid from aqueous solution under any conditions is reported. This result suggests, but does not prove, that long-term very slow formation of NpO2 might be an important long-term control on neptunium migration. Even at 200oC, the kinetics can be sluggish on typical experimental time scales. Though not reported in Part A, a similar situation may exist for Pu, and NpO2 and PuO2 may potentially form solid solutions. Under reducing conditions, UO2 might join in. Part B examines the interaction of Np(V) with the uranium mineral schoepite. Is neptunium incorporated into the crystal structure as a solid-solution component, or does it just sorb onto the mineral surface? The results presented here suggest that it basically just sorbs onto the surface, which would be a less effective process in limiting neptunium migration. This is not a surprising result, as schoepite is a relatively simple solid of U(VI). There is no obvious means to compensate for the charge difference between U(VI) and Np(V) without introducing unfavorable energetics. However, the results reported here do not rule out a possible substitution of Np(VI) in schoepite or other U

  19. Effects of organic solvents on the partitioning of enzymes in aqueous two-phase systems.

    Science.gov (United States)

    Johansson, G; Kopperschläger, G

    1987-02-13

    Organic solvents (ethylene glycol, glycerol, dimethyl sulphoxide, dimethylformamide, dioxane, methanol and propanol-2, as well as sucrose and urea) have been included in aqueous two-phase (liquid-liquid) systems comprised of water, dextran and poly(ethylene glycol). The concentration of the organic solvent was in most cases 20% (w/w). The influence of these solvents on the phase-forming properties, the volume ratio, the freezing point and the partitioning of a polymer-bound ligand, Procion Red HE-3B poly(ethylene glycol), has been studied. The partition coefficients for alkaline phosphatase decrease with ethylene glycol, glycerol, sucrose and urea (factors of 0.25-0.5), but increase with the other substances (factors of 1.2-1.6). The temperature effects on the partitioning of alkaline phosphatase from calf intestine as well as of phosphofructokinase from yeast in systems containing ethylene glycol have been studied and compared with partitioning in standard systems, not containing solvents. The possible uses of the above systems for partitioning studies of enzymes are discussed. PMID:2951391

  20. Rapid synthesis of zeolitic imidazolate framework-8 (ZIF-8) nanocrystals in an aqueous system

    KAUST Repository

    Pan, Yichang

    2011-01-01

    We report here the first example of ZIF materials synthesized in aqueous solution. The synthesis was performed at room temperature and typically took several minutes compared to hours and days in non-aqueous conditions. The obtained product were ZIF-8 nanocrystals having size of ∼85 nm and showed excellent thermal, hydrothermal and solvothermal stabilities. © 2011 The Royal Society of Chemistry.

  1. Heterogeneous equilibria in the Mm(BUO5)m · nH2O-aqueous HCl system

    International Nuclear Information System (INIS)

    Solubility of crystal uranoborate of alkali and alkaline-earth metals of the composition Mm(BUO5)m · nH2O (Mm = Li-Cs, Mg-Ba) in HCl aqueous solutions 10-4-10-1 M at 25 deg C was studied. Relying on the experimental data obtained, a quantitative model of the aqueous system was suggested and physicochemical description of the uranoborates state in solutions was given. Using the method of equilibrium thermodynamics, the standard thermodynamic functions of the compounds studied were ascertained

  2. Approach to the extreme safety in a nuclear fuel reprocessing system in mild aqueous solutions

    International Nuclear Information System (INIS)

    The purpose of the experiment is to establish a new nuclear fuel reprocessing system, which is aimed to achieve the extreme safety. In order to avoid any potential danger of explosion, all processes are made by the precipitation method at room temperature. The system consists of the following processes: 1. crystallization of uranyl nitrate from a dissolved fuel solution by cooling the solution; 2. complex formation of UO22+ and Pu4+ with carbonate ion by the addition of Na2CO3-NaHCO3 solution adjusting pH to 9, followed by the separation of a precipitate containing the major fission products by the centrifugation method; 3. separation of Cs as a precipitate of cesium tetraphenylborate; 4. recovery of U and Pu as precipitates of hydroxo compounds from the alkaline solution by the addition of NaOH solution ; 5. separation of Sr from the precipitate in process 2; 6. recovery of NaHCO3 from the NaOH solution by bubbling CO2 gas. As a result, 99.95% of the U was recovered with the least amount of fission products. Pu are expected to be recovered in the same way as U. In conclusion, the present reprocessing system enables us to recover U and Pu in high ratios from spent nuclear fuel by means of a simple precipitation method, to separate hazardous Cs and Sr from high-level waste, and to exclude any potential danger owing to chemical processes under mild aqueous conditions. (author)

  3. Investigation of radioprotective effects of aqueous extract of sauseurea obyallata on immune system of mice

    International Nuclear Information System (INIS)

    Objective: To investigate the radioprotective effects of test compound on immune system of mice from radiation injury. Methods: Immunologic function and general state of mice were shown by swimming experiment with the weighing of spleen, thymus and computing their indexs, hemolysin mensurate experiment and PHA stimulated lymphocyte transformation experiment. All mice were irradiated with 6 Gy and received the test compound by gavage for 14 days, 7 days before irradiation and 7 days after irradiation. All the indicators were measured according to established methods. The data went through Statistical analysis by spss11.5. Results: Irradiation has obvious influence on the immune function and systemic state of mice. In swimming experiment, mice in the treatment group swim longer than the model group, but is of no significant difference. The thymus indexes are higher in treatment groups than in model group, especially the HD group, compared with model group, the differences are obvious (P<0.05). There is no obvious difference between treatment groups and model group with OD value in hemolysin mensurate experiment. Conclusions: Aqueous Extract of Sauseurea Obyallata may have radioprotective effects on immune system of mice, which deserves further exploration in the compound preparing, analysis of Chemical Compositions and the dose and mode and the treatment duration of the compound. (authors)

  4. Nucleation and capture of condensible airborne contaminants in an aqueous scrubbing system

    International Nuclear Information System (INIS)

    The fate of condensible contaminants in an aqueous scrubbing system was evaluated. Knowledge of the behavior of volatile fission product compounds is important in evaluating the effectiveness of emergency air cleaning systems proposed for use in containment systems of breeder reactor plants. When a high temperature air stream passes through a spray quench chamber, very large cooling rates occur in the drop boundary layers. These large cooling rates cause large supersaturations in airborne concentrations of condensible contaminants, and one predicts that most condensation would take place through homogeneous nucleation. The very small particles formed would agglomerate, and attach to sodium aerosol particles which would be present. In the study the overall removal efficiency of volatile fission product species (typified by NaI, SeO2, and Sb2O3) in an air cleaning train (quench chamber, venturi scrubber, and fibrous bed) was theoretically evaluated. The overall removal efficiency of condensible materials was found to be lower than that for sodium compound aerosols because the freshly condensed particles would be smaller in size. For a base case, a removal efficiency of 99.97 percent was predicted for condensible materials. The fibrous bed scrubber exhibited superior particle removal characteristics for small particles compared to the quench chamber and venturi scrubber. Its removal efficiency exceeded 97 percent for even the most penetrating particle size (about 0.4 micron aerodynamic diameter). Therefore, all condensible fission products would be removed with efficiencies exceeding 97 percent

  5. Progress on the biphase turbine at Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Cerini, D.; Hays, L.; Studhalter, W. [Douglas Energy Company, Placentia, CA (United States)

    1997-12-31

    The status of a Biphase turbine power plant being installed at the Cerro Prieto geothermal field is presented. The major modules for the power plant are completed except for a back pressure steam turbine. The power plant will be started in April 1997 with the Biphase turbine alone followed by the addition of the steam turbine module two months later. The current power plant performance level is 2780 kWe due to a decline in the well. An increase in power output to 4060 kWe by adding the flow from another well is planned. The addition of five Biphase power plants with a total power output of 21.2 megawatts is described.

  6. RECOVERY OF CARBOXYLIC ACIDS FROM AQUEOUS SOLUTIONS BY LIQUID-LIQUID EXTRACTION WITH A TRIISOOCTYLAMINE DILUENT SYSTEM

    Directory of Open Access Journals (Sweden)

    G. Malmary

    2001-12-01

    Full Text Available Tertiary alkylamines in solution with organic diluents are attractive extractants for the recovery of carboxylic acids from dilute aqueous phases. The aim of this study was to investigate the mechanism for extraction of organic acids from water by a long-chain aliphatic tertiary amine. In order to attain this objective, we studied the liquid-liquid equilibria between the triisooctylamine + 1-octanol + n-heptane system as solvent and an aqueous solution of an individual carboxylic acid such as citric, lactic and malic acids. The experiments showed that the partition coefficient for a particular organic acid depends on the kind of solute, notably when the acid concentration in the aqueous phase is low. A mathematical model, where both chemical association and physical distribution are taken into consideration, is proposed. The model suggests that the various complexes obtained between amine and organic acids contribute to the distribution of the solute between the coexisting phases in equilibrium.

  7. Momentum, Heat, and Neutral Mass Transport in Convective Atmospheric Pressure Plasma-Liquid Systems and Implications for Aqueous Targets

    CERN Document Server

    Lindsay, Alexander; Slikboer, Elmar; Shannon, Steven; Graves, David

    2015-01-01

    There is a growing interest in the study of plasma-liquid interactions with application to biomedicine, chemical disinfection, agriculture, and other fields. This work models the momentum, heat, and neutral species mass transfer between gas and aqueous phases in the context of a streamer discharge; the qualitative conclusions are generally applicable to plasma-liquid systems. The problem domain is discretized using the finite element method. The most interesting and relevant model result for application purposes is the steep gradients in reactive species at the interface. At the center of where the reactive gas stream impinges on the water surface, the aqueous concentrations of OH and ONOOH decrease by roughly 9 and 4 orders of magnitude respectively within 50 $\\mu$m of the interface. Recognizing the limited penetration of reactive plasma species into the aqueous phase is critical to discussions about the therapeutic mechanisms for direct plasma treatment of biological solutions. Other interesting results fro...

  8. Poly(3-hydroxybutyrate) and Eudragit E microparticles: a release system to enhance the aqueous solubility of felodipine and simvastatin

    International Nuclear Information System (INIS)

    Poor water-soluble drugs are a problem for the development of oral solid dosage forms, since it has great potential for low bioavailability. Thus, release systems that promote the increase of aqueous solubility of these drugs are advantageous. This study aimed to evaluate the feasibility of incorporation of felodipine and simvastatin in polymeric microparticles, to improve the aqueous solubility of the drugs. Microparticles of poly(3-hydroxybutyrate) [PHB] and Eudragit E was prepared by emulsion - solvent evaporation technique and characterized as to morphology and encapsulation efficiency of the drugs. Particles with spherical shapes and high levels of drug encapsulated were obtained. There was a significant increase in aqueous solubility of felodipine and simvastatin after its incorporation into the polymeric microparticles. X-ray diffraction analysis showed the conversion of both drugs to amorphous form, which may have contributed to increased the solubility. (author)

  9. Rate-limiting step analysis of the microbial desulfurization of dibenzothiophene in a model oil system

    OpenAIRE

    Abin-Fuentes, Andres; Leung, James C.; Mohamed, Magdy El-Said; Wang, Daniel IC; Prather, Kristala LJ

    2013-01-01

    A mechanistic analysis of the various mass transport and kinetic steps in the microbial desulfurization of dibenzothiophene (DBT) by Rhodococcus erythropolis IGTS8 in a model biphasic (oil–water), small-scale system was performed. The biocatalyst was distributed into three populations, free cells in the aqueous phase, cell aggregates and oil–adhered cells, and the fraction of cells in each population was measured. The power input per volume (P/V) and the impeller tip speed (v[subscript tip]) ...

  10. Case Report: Multifocal biphasic squamoid alveolar renal cell carcinoma

    Science.gov (United States)

    Lopez, Jose Ignacio

    2016-01-01

    A multifocal biphasic squamoid alveolar renal cell carcinoma in a 68-year-old man is reported. Four different peripheral tumor nodules were identified on gross examination. A fifth central tumor corresponded to a conventional clear cell renal cell carcinoma. Biphasic squamoid alveolar renal cell carcinoma is a rare tumor that has been very recently characterized as a distinct histotype within the spectrum of papillary renal cell carcinoma. Immunostaining with cyclin D1 seems to be specific of this tumor subtype. This is the first reported case with multifocal presentation. PMID:27158455

  11. Partition of Chiral pharmaceutical intermediate R(-)-Mandelic Acid in Aqueous Two-Phase System of Poly(ethylene glycol)-Ammonium Sulfate

    Institute of Scientific and Technical Information of China (English)

    Xu Xiaoping; Li Zhongqin; Chen Jiebo; Huang Xinghua

    2004-01-01

    An aqueous two-phase system of poly (ethylene glycol)-ammonium sulfate was employed to separate R (-)-mandelic acid.The result showed that R (-)-mandelic acid has priority to partition in PEG-rich top phase. This indicated that aqueous two-phase is a very suitable system for separation of R(-)-mandelic acid.

  12. Membraneless dialysis of strontium in aqueous liquid-liquid milk-pectin system

    International Nuclear Information System (INIS)

    Binding of added strontium by milk proteins under native conditions was investigated using pectin of various degrees of esterification. The partition of strontium, as well as cesium and europium, in aqueous two-phase milk-pectin system, is discussed in terms of 'membraneless dialysis' and described by Donnan equilibria, and compared with the distribution between cation exchanger and milk, artificial milk serum, or pectin solutions. When going from pectin with a degree of esterification D.E. = 93.2 to 61.4, the distribution of strontium decreases for about 40% in favor of pectin phase and this was explained by a relatively lower degree of dissociation of free carboxyle groups of pectin. The low-molecular fraction of added strontium in milk was assessed from Dowex 50*8 sorption data to be 31%, and that of cesium and europium 58% and 40%, respectively. However, distribution ratio of strontium and europium in milk/pectin system is much higher than it would correspond to the ion exchanger adsorption data. (author) 16 refs.; 2 tabs

  13. Partition of volatile compounds in pea globulin-maltodextrin aqueous two-phase system.

    Science.gov (United States)

    Nguyen, Thanh Dat; Lafarge, Céline; Murat, Chloé; Mession, Jean-Luc; Cayot, Nathalie; Saurel, Rémi

    2014-12-01

    This study is based on the assumption that the off-flavour of pea proteins might be decreased using the retention of volatile compounds by a mixture with another biopolymer. The partition of volatile compounds in an aqueous system containing pea protein and maltodextrins was followed under thermodynamic incompatibility conditions. Firstly, the phase diagram of the system was established. Then, the partition of aroma compounds between the phase rich in protein and the phase rich in maltodextrin was measured by SPME-GC-MS. There was a transfer of volatile compounds during phase separation. Variations of pH were also used to vary the retention of volatile compounds by proteins. The concentration of volatile compounds in protein solution at pH 2.4 was higher than at pH 7.2. It was possible to increase the transfer of volatile compounds from the phase rich in protein to the phase rich in maltodextrin using the effect of pH on protein denaturation. PMID:24996351

  14. Hydrate phase equilibria of CO2+N2+aqueous solution of THF, TBAB or TBAF system

    DEFF Research Database (Denmark)

    Sfaxi, Imen Ben Attouche; Durand, Isabelle; Lugo, Rafael;

    2014-01-01

    We report hydrate dissociation conditions of CO2 (15 and 30mol%)+N2 (85 and 70mol%) in the presence of aqueous solutions of THF, TBAB or TBAF. The concentrations of TBAB and TBAF in the aqueous solutions are 5wt% and 9wt% while THF concentration in aqueous solution is 3mol%. Two different...... experimental techniques including isochoric pressure search method and a DSC method are used to measure the hydrate dissociation conditions. A comparison is finally made with the literature data. It is expected that this study provides better understanding of hydrate phase equilibria associated with CO2...... capture. © 2014 Elsevier Ltd....

  15. The phase transport and reactions of γ-irradiated aqueous-ionic liquids

    International Nuclear Information System (INIS)

    A novel technology based on the transfer of chemical species across water/ionic liquid interfaces via specific complexation reactions is currently being considered for the separation and sequestration of metal ion contaminants from radioactive waste effluents in the nuclear fuel cycle. An ideal solvent for these applications should have a high intrinsic selectivity for a targeted metal or group of metals (e.g., trans-Pu actinides, lanthanides, or other fission products), an efficient switching mechanism (between complexation and decomplexation), and a high immiscibility with aqueous solutions. These characteristics must be maintained in the chemical, radiation, and mass transport environments present during the separation process. Ionic liquids (ILs) have an almost negligible vapour pressure and high thermal stability. Their ability to dissolve a wide range of substrate molecules and potential to be highly resilient in radiation fields make ILs particularly promising media. The separation efficiency of the biphasic system will depend on many parameters, including the aqueous oxidation state of the targeted metal ion, and the thermodynamics and kinetics of interfacial transport and metal-ligand complex formation at the water/IL interface or in the IL phase. The most uncertain and unstudied area for these applications is the effect of ionizing radiation on the stability and separation efficiency of the biphasic system. The present study investigates the effect of γ-radiation on gas/IL and water/IL interfacial stability and mass transfer with trihexyltetradecylphosphonium bis(trifluoromethyl-sulfonyl)imide, a phosphonium-based IL. The IL, in contact with either gas or water, was irradiated at a dose rate of 6.4 kGy·h-1. Gas-phase samples were analyzed by gas chromatography-mass spectrometry (GC-MS) and the changes in the IL and aqueous phases were monitored by conductivity measurements and Raman spectroscopy. In this paper we discuss these observations and their

  16. Cytogenotoxicity of Cymbopogon citratus (DC) Stapf (lemon grass) aqueous extracts in vegetal test systems

    OpenAIRE

    Saulo M. Sousa; Pâmela S. Silva; Lyderson F. Viccini

    2010-01-01

    The lemon grass, Cymbopogon citratus (DC) Stapf, is an important species of Poaceae family commonly used in the folk medicine in many countries. The aim of this study was to investigate the cytotoxic and genotoxic effects of aqueous extracts from C. citratus leaves on Lactuca sativa (lettuce) root tip meristem cells by cytogenetic studies that have never been done before for lemon grass extracts. For this, lettuce seeds were treated for 72h with different concentrations of lemon grass aqueous...

  17. Aqueous Two-phase Systems with Ultrasonic Extraction Used for Extracting Phenolic Compounds from Inonotus obliquus

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Yan-xia; LIU; Yu-bing; LIU; Feng; ZHENG; Wei-fa

    2013-01-01

    Objective To optimize the extracting technology of assessing the maximum yield of phenolic compounds (PC) from Inonotus obliquus by single factor experiments and orthogonal array design methods through aqueous two-phase systems combined with ultrasonic extraction. Methods The range of the independent variables, namely levels of acetone and ammonium sulfate, and ultrasonic time were identified by a first set of single factor experiments. The actual values of the independent variables coded at four levels and three factors were selected based on the results of the single factor experiments. Subsequently, the levels of acetone and ammonium sulfate, and ultrasonic time were optimized using the orthogonal array method. Results The optimum conditions for the extraction of PC were found to use 7.0 mL acetone, 5.5 mg ammonium sulfate, with ultrasonic time for 5 min. Under these optimized conditions, the experimental maximum yield of PC was 37.8 mg/g, much higher than that of the traditional ultrasonic extraction (UE, 29.0 mg/g). And the PC obtained by this method had stronger anti-oxidative activities than those by traditional UE method. Conclusion These results indicate the suitability of the models developed and the success in optimizing the extraction conditions. This is an economical and efficient method for extracting polyphenols from I. obliquus.

  18. Aqueous Two-phase Systems with Ultrasonic Extraction Used for Extracting Phenolic Compounds from Inonotus obliquus

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yan-xia; LIU Yu-bing; LIU Feng; ZHENG Wei-fa

    2013-01-01

    Objective To optimize the extracting technology of assessing the maximum yield of phenolic compounds (PC)from Inonotus obliquus by single factor experiments and orthogonal array design methods through aqueous two-phase systems combined with ultrasonic extraction.Methods The range of the independent variables,namely levels of acetone and ammonium sulfate,and ultrasonic time were identified by a first set of single factor experiments.The actual values of the independent variables coded at four levels and three factors were selected based on the results of the single factor experiments.Subsequently,the levels of acetone and ammonium sulfate,and ultrasonic time were optimized using the orthogonal array method.Results The optimum conditions for the extraction of PC were found to use 7.0 mL acetone,5.5 mg ammonium sulfate,with ultrasonic time for 5 min.Under these optimized conditions,the experimental maximum yield of PC was 37.8 mg/g,much higher than that of the traditional ultrasonic extraction (UE,29.0 mg/g).And the PC obtained by this method had stronger anti-oxidative activities than those by traditional UE method.Conclusion These results indicate the suitability of the models developed and the success in optimizing the extraction conditions.This is an economical and efficient method for extracting polyphenols from Ⅰ.obliquus.

  19. Wash Solution Bath Life Extension for the Space Shuttle Rocket Motor Aqueous Cleaning System

    Science.gov (United States)

    Saunders, Chad; Evans, Kurt; Sagers, Neil

    1999-01-01

    A spray-in-air aqueous cleaning system, which replaced 1,1,1 trichloroethane (TCA) vapor degreasing, is used for critical cleaning of Space Shuttle Redesigned Solid Rocket Motor (RSRM) metal parts. Small-scale testing demonstrated that the alkaline-based wash solution possesses adequate soil loading and cleaning properties. However, full-scale testing exhibited unexpected depletion of some primary components of the wash solution. Specifically, there was a significant decrease in the concentration of sodium metasilicate which forced change-out of the wash solution after eight days. Extension of wash solution bath life was necessary to ease the burden of frequent change-out on manufacturing. A laboratory study supports a depletion mechanism that is initiated by the hydrolysis of sodium tripolyphosphate (STPP) lowering the pH of the solution. The decrease in pH causes polymerization and subsequent precipitation of sodium metasilicate (SM). Further investigation showed that maintaining the pH was the key to preventing the precipitation of the sodium metasilicate. Implementation to the full scale operation demonstrated that periodic additions of potassium hydroxide (KOH) extended the useful bath life to more than four months.

  20. Multi-equilibrium system based on sertraline and β-cyclodextrin supramolecular complex in aqueous solution.

    Science.gov (United States)

    Passos, Joel J; De Sousa, Frederico B; Lula, Ivana S; Barreto, Elison A; Lopes, Juliana Fedoce; De Almeida, Wagner B; Sinisterra, Rubén D

    2011-12-12

    Sertraline (SRT) is a widely used antidepressant whose poor solubility in water limits its oral applicability. Thus, the aim of this work was the evaluation of a multi-equilibrium system based on β-cyclodextrin (βCD) and SRT. The inclusion compounds (ICs) were investigated by infrared spectroscopy, isothermal titration calorimetry (ITC) and (1)H and 2D ROESY nuclear magnetic resonance experiments. SRT solubility was predicted in vitro in water and biomimetic fluids. The SRT in presence of βCD at 1:1 and 1:2 molar ratios was more soluble than free SRT in all biomimetics media investigated. The FTIR-HATR showed that βCD νC-O-C stretching band was reduced in presence of SRT, suggesting the interactions between them. Additionally, titration process and Job's plot provided information on the ICs stoichiometry and evidenced the multi-equilibrium coexistence in aqueous solution. According to the ITC, SRT:βCD interaction process was spontaneous and exothermic with a high affinity binding constant (K=14,726 M(-1)). Additionally, the stoichiometry coefficient (n) was 1.63, which was comparable to that found by FITR-HATR. The (1)H and 2D ROESY verified multiple SRT sites included into the host cavity. Theoretical calculations depicted the relative energy of different proposed ICs structures, in which the 1:2 IC was the most stable. PMID:21963467

  1. Partitioning in aqueous two-phase systems: Analysis of strengths, weaknesses, opportunities and threats.

    Science.gov (United States)

    Soares, Ruben R G; Azevedo, Ana M; Van Alstine, James M; Aires-Barros, M Raquel

    2015-08-01

    For half a century aqueous two-phase systems (ATPSs) have been applied for the extraction and purification of biomolecules. In spite of their simplicity, selectivity, and relatively low cost they have not been significantly employed for industrial scale bioprocessing. Recently their ability to be readily scaled and interface easily in single-use, flexible biomanufacturing has led to industrial re-evaluation of ATPSs. The purpose of this review is to perform a SWOT analysis that includes a discussion of: (i) strengths of ATPS partitioning as an effective and simple platform for biomolecule purification; (ii) weaknesses of ATPS partitioning in regard to intrinsic problems and possible solutions; (iii) opportunities related to biotechnological challenges that ATPS partitioning may solve; and (iv) threats related to alternative techniques that may compete with ATPS in performance, economic benefits, scale up and reliability. This approach provides insight into the current status of ATPS as a bioprocessing technique and it can be concluded that most of the perceived weakness towards industrial implementation have now been largely overcome, thus paving the way for opportunities in fermentation feed clarification, integration in multi-stage operations and in single-step purification processes. PMID:26213222

  2. Optimization of Biosorptive Removal of Dye from Aqueous System by Cone Shell of Calabrian Pine

    Directory of Open Access Journals (Sweden)

    Fatih Deniz

    2014-01-01

    Full Text Available The biosorption performance of raw cone shell of Calabrian pine for C.I. Basic Red 46 as a model azo dye from aqueous system was optimized using Taguchi experimental design methodology. L9 (33 orthogonal array was used to optimize the dye biosorption by the pine cone shell. The selected factors and their levels were biosorbent particle size, dye concentration, and contact time. The predicted dye biosorption capacity for the pine cone shell from Taguchi design was obtained as 71.770 mg g−1 under optimized biosorption conditions. This experimental design provided reasonable predictive performance of dye biosorption by the biosorbent (R2: 0.9961. Langmuir model fitted better to the biosorption equilibrium data than Freundlich model. This displayed the monolayer coverage of dye molecules on the biosorbent surface. Dubinin-Radushkevich model and the standard Gibbs free energy change proposed physical biosorption for predominant mechanism. The logistic function presented the best fit to the data of biosorption kinetics. The kinetic parameters reflecting biosorption performance were also evaluated. The optimization study revealed that the pine cone shell can be an effective and economically feasible biosorbent for the removal of dye.

  3. Sustainable AC/AC hybrid electrochemical capacitors in aqueous electrolyte approaching the performance of organic systems

    Science.gov (United States)

    Abbas, Qamar; Babuchowska, Paulina; Frąckowiak, Elżbieta; Béguin, François

    2016-09-01

    A high energy hybrid AC/AC electrochemical capacitor has been realized in aqueous Li2SO4+KI electrolyte mixture. Owing to the redox processes associated with the 2I-/I2 system, the positive electrode operates in narrow potential range and displays high capacity. During prolonged potentiostatic floating at 1.6 V, the hybrid cell demonstrates remarkably stable capacitance and resistance. Analyses by temperature programmed desorption after floating at 1.6 V proved that oxidation of the positive AC electrode is prevented by the use of Li2SO4+KI, which enables the maximum potential of this electrode to be shifted below the water oxidation potential. When charged at 0.2 A g-1 up to U = 1.6 V, the hybrid cell displays a high capacitance of 75 F g-1 (300 F g-1 per mass of one electrode) compared to 47 F g-1 (188 F g-1 per mass of one electrode) for a symmetric cell in Li2SO4. At 0.2 A g-1 up to 1.6 V, the hybrid capacitor in Li2SO4+KI displays an energy density of 26 Wh kg-1 which approaches the energy density of 30.9 Wh kg-1 measured when the same carbon is implemented in a capacitor using TEABF4/ACN electrolyte and charged up to 2.5 V.

  4. Environmental fate of spinosad. 1. Dissipation and degradation in aqueous systems.

    Science.gov (United States)

    Cleveland, Cheryl B; Bormett, Gary A; Saunders, Donald G; Powers, Fred L; McGibbon, Alec S; Reeves, Graham L; Rutherford, Laura; Balcer, Jesse L

    2002-05-22

    Spinosad is a bacterially derived insect control agent consisting of two active compounds, spinosyns A and D. The objective of this paper is to describe the environmental fate of spinosad in aquatic systems. To this end, several studies performed to meet regulatory requirements are used to study the fate and degradation in individual environmental media. Specifically, investigations of abiotic (hydrolysis and photolysis) and biotic (aerobic and anaerobic aquatic) processes are described. Understanding developed from the laboratory-based studies has been tested and augmented by an outdoor microcosm study. Understanding of aquatic fate is a building block for a complete environmental safety assessment of spinosad products (Cleveland, C. B.; Mayes, M. A.; Cryer, S. A. Pest Manag. Sci. 2001, 58, 70-84). From individual investigations, the following understanding of dissipation emerges: (1) Aqueous photolysis of spinosad is rapid (observed half-lives of spinosyn aglycon degradates. (3) Hydrolytic degradation involves loss of the forosamine sugar and water and reduction on the macrolide ring to a double bond at the 16,17-position. PMID:12009994

  5. Process boundaries of irreversible scCO2 -assisted phase separation in biphasic whole-cell biocatalysis.

    Science.gov (United States)

    Brandenbusch, Christoph; Glonke, Sebastian; Collins, Jonathan; Hoffrogge, Raimund; Grunwald, Klaudia; Bühler, Bruno; Schmid, Andreas; Sadowski, Gabriele

    2015-11-01

    The formation of stable emulsions in biphasic biotransformations catalyzed by microbial cells turned out to be a major hurdle for industrial implementation. Recently, a cost-effective and efficient downstream processing approach, using supercritical carbon dioxide (scCO2 ) for both irreversible emulsion destabilization (enabling complete phase separation within minutes of emulsion treatment) and product purification via extraction has been proposed by Brandenbusch et al. (2010). One of the key factors for a further development and scale-up of the approach is the understanding of the mechanism underlying scCO2 -assisted phase separation. A systematic approach was applied within this work to investigate the various factors influencing phase separation during scCO2 treatment (that is pressure, exposure of the cells to CO2 , and changes of cell surface properties). It was shown that cell toxification and cell disrupture are not responsible for emulsion destabilization. Proteins from the aqueous phase partially adsorb to cells present at the aqueous-organic interface, causing hydrophobic cell surface characteristics, and thus contribute to emulsion stabilization. By investigating the change in cell-surface hydrophobicity of these cells during CO2 treatment, it was found that a combination of catastrophic phase inversion and desorption of proteins from the cell surface is responsible for irreversible scCO2 mediated phase separation. These findings are essential for the definition of process windows for scCO2 -assisted phase separation in biphasic whole-cell biocatalysis. PMID:26012371

  6. Intrinsically Stretchable Biphasic (Solid–Liquid) Thin Metal Films

    OpenAIRE

    Hirsch, Arthur Edouard; Michaud, Hadrien Olivier; Gerratt, Aaron Powers; Mulatier, Séverine; Lacour, Stéphanie

    2016-01-01

    Stretchable biphasic conductors are formed by physical vapor deposition of gallium onto an alloying metal film. The properties of the photolithography-compatible thin metal films are highlighted by low sheet resistance (0.5 Ω sq−1) and large stretchability (400%). This novel approach to deposit and pattern liquid metals enables extremely robust, multilayer and soft circuits, sensors, and actuators.

  7. Intrinsically Stretchable Biphasic (Solid-Liquid) Thin Metal Films.

    Science.gov (United States)

    Hirsch, Arthur; Michaud, Hadrien O; Gerratt, Aaron P; de Mulatier, Séverine; Lacour, Stéphanie P

    2016-06-01

    Stretchable biphasic conductors are formed by physical vapor deposition of gallium onto an alloying metal film. The properties of the photolithography-compatible thin metal films are highlighted by low sheet resistance (0.5 Ω sq(-1) ) and large stretchability (400%). This novel approach to deposit and pattern liquid metals enables extremely robust, multilayer and soft circuits, sensors, and actuators. PMID:26923313

  8. Production of vanillin from isoeugenol by microbial conversion in aqueous biphasic system%两相体系中微生物法转化异丁香酚生成香草醛的研究

    Institute of Scientific and Technical Information of China (English)

    赵丽青; 何军邀; 孙志浩; 郑璞

    2005-01-01

    从土壤中筛选获得一株能耐受高浓度异丁香酚并高效转化生成香草醛的纺锤芽孢杆菌Bacillus fusiformis菌株CGMCC1347,研究了微生物细胞在异丁香酚-水两相体系中转化异丁香酚制备香草醛的过程.在异丁香酚体积分数60%,初始pH 4.0,温度37 ℃,转速180 r/min的条件下,转化72 h,湿细胞质量浓度达60 g/L时,香草醛质量浓度高达46.10 g/L.

  9. Effect of cationic surfactant structure on the condensation reaction in aqueous-organic biphasic catalytic system%水/有机两相体系中苯甲醛与苯乙酮缩合反应的研究

    Institute of Scientific and Technical Information of China (English)

    林棋; 郭秋燕; 林韬伟

    2009-01-01

    合成了3种季铵盐型阳离子表面活性荆(C16H33)2N(CH3)2Br(双十六烷基二甲基溴化铵),C16H33,NC33H45(CH3)2Br(二十二烷基十六烷基二甲基溴化铵),C16H33NC12H25(CH3)2Br(十六烷基十二烷基二甲基溴化铵),并考察了其对水/有机两相体系中苯甲醛与苯乙酮Aldol缩合反应性能的影响.结果显示,含有两条疏水长链的阳离子表面活性剂对水/有机两相体系中苯甲醛与苯乙酮Aldol缩合反应具有明显的加速作用,其催化活性明显高于其它类型的表面活性剂;结果还显示,阳离子表面活性剂分子中疏水碳链的数目增加、疏水碳链的增长均有利于Aldol缩合反应.

  10. Use of polyethylene glycol (PEG) based aqueous biphasic system (ABS) for the extraction of Pu(IV), Pu(VI) and Am(III) with 18-crown-6. A thermodynamic study

    International Nuclear Information System (INIS)

    Extraction of Pu(IV), Pu(VI) and Am(III) using PEG-2000/ (NH4)2SO4 (40% w/w of each) ABS with 18-crown-6 (18-C-6) as the extractant was studied at four fixed temperatures in the range 288 to 318 K. The distribution ratios follow the order: Pu(VI) > Pu(IV) > Am(III). The species extracted were identified to be [Pu x 2(18-C-6)](SO4)2, [PuO2 x (18-C-6)]SO4 and [Am x 2(18-C-6)](SO4)1.5 for Pu(IV), Pu(VI) and Am(III), respectively. The equilibrium constants (K) evaluated for the extraction reactions follow the order, KPu(IV) > KPu(VI) > KAm(III) as expected in accordance with the axial charge experienced by the incoming ligand (18-C-6). The thermodynamic parameters evaluated at 298 K showed the reaction to be stabilized by the decrease in enthalpy and counteracted by the decrease in entropy in all the three cases. The large decrease in the enthalpy observed in all the cases showed that there is direct bonding of crown ether to the central metal atom (i.e., the formation of inner sphere complex). (author)

  11. Biphasic survival analysis of trypanotolerance QTL in mice.

    Science.gov (United States)

    Koudandé, O D; Thomson, P C; Bovenhuis, H; Iraqi, F; Gibson, J P; van Arendonk, J A M

    2008-04-01

    A marker-assisted introgression (MAI) experiment was conducted to transfer trypanotolerance quantitative trait loci (QTL) from a donor mouse strain, C57BL/6, into a recipient mouse strain, A/J. The objective was to assess the effect of three previously identified chromosomal regions on mouse chromosomes 1 (MMU1), 5 (MMU5) and 17 (MMU17) in different genetic backgrounds on the survival pattern following infection with Trypanosoma congolense. An exploratory data analysis revealed a biphasic pattern of time to death, with highly distinct early and late mortality phases. In this paper, we present survival analysis methods that account for the biphasic mortality pattern and results of reanalyzing the data from the MAI experiment. The analysis with a Weibull mixture model confirmed the biphasic pattern of time to death. Mortality phase, an unobserved variable, appears to be an important factor influencing survival time and is modeled as a binary outcome variable using logistic regression analysis. Accounting for this biphasic pattern in the analysis reveals that a previously observed sex effect on average survival is rather an effect on proportion of mice in the two mortality phases. The C57BL/6 (donor) QTL alleles on MMU1 and MMU17 act dominantly in the late mortality phase while the A/J (recipient) QTL allele on MMU17 acts dominantly in the early mortality phase. From this study, we found clear evidence for a biphasic survival pattern and provided models for its analysis. These models can also be used when studying defense mechanisms against other pathogens. Finally, these approaches provide further information on the nature of gene actions. PMID:18253157

  12. Study of an aqueous lithium chloride desiccant system Part II: Desiccant regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Fumo, Nelson [Universidad Nacional Experimental del Tachira, San Cristobal (Venezuela); Goswami, Yogi [University of Florida, Gainesville (United States)

    2000-07-01

    Desiccant systems have been proposed as alternative to handle the latent load in vapor compression air conditioning for energy saving. The air dehumidification occurs because of the difference in vapor pressure which let the moisture diffuse from the air to the liquid desiccant. The diffused moisture cause a dilution of the desiccant which must be regenerated to return it to the original conditions. This paper presents the results from a study of the performance of a packed tower regenerator for an aqueous lithium chloride desiccant dehumidification system. The rate of water evaporation, as well as the effectiveness of the regeneration process were assessed under the effects of variables such as air and desiccant flow rates, air temperature and humidity, and desiccant temperature and concentration. A variation of the oeberg and Goswami mathematical model was used to predict the experimental findings given satisfactory results. [Spanish] Se han propuesto sistemas desecantes para hacerse cargo de la carga latente en acondicionamiento de aire por compresion de vapor para el ahorro de energia. La deshumidificacion del aire ocurre en razon de la diferencia de presion de vapor que deja la humedad difusa del aire en el desecante liquido. La humedad difusa del aire origina una dilucion del desecante el cual debe de ser regenerado para regresarlo a sus condiciones originales. Este documento presenta los resultados de un estudio sobre el comportamiento de un regenerador de torre empacada para un sistema de deshumidificacion de solucion desecante de cloruro de litio. El regimen de evaporacion de agua, asi como tambien la efectividad del proceso de regeneracion que se evaluo bajo los efectos de variables tales como los regimenes de flujo de aire y de desecante, temperatura del aire y humedad, y temperatura y concentracion del desecante. Una variacion del modelo matematico de Oberg y Goswami se uso para predecir los resultados experimentales que dieron resultados satisfactorios.

  13. Study of an aqueous lithium chloride desiccant system Part I: Air dehumidification

    Energy Technology Data Exchange (ETDEWEB)

    Fumo, Nelson [Universidad Nacional Experimental del Tachira, San Cristobal (Venezuela); Goswami, Yogi [University of Florida, Gainesville (United States)

    2000-07-01

    Desiccant systems have been proposed as energy saving alternative to vapor compression air conditioning for handling the latent load. Use of liquid desiccants offers several design and performance advantages over solid desiccants, especially when solar energy is used for regeneration. For liquid-gas contact, packed towers with low pressure drop have offered good heat and mass transfer characteristics for compact designs. This paper presents the results from a study of the performance of a packed tower absorber for an aqueous lithium chloride desiccant dehumidification system. The rate of dehumidification, as well as the effectiveness of the dehumidification process were assessed under the effects of variables such as air and desiccant flow rates, air temperature and humidity, and desiccant temperature and concentration. A variation of the oeberg and Goswami mathematical model was used to predict the experimental findings given satisfactory results. [Spanish] Se han propuesto sistemas de desecacion como una alternativa de ahorro de energia para el acondicionamiento de aire mediante la compresion de vapor para manejar la carga latente. El uso de desecantes liquidos ofrece varias ventajas de diseno y de rendimiento sobre los desecantes solidos, especialmente cuando la energia solar se usa para la regeneracion. Para el contacto liquido-gas han dado buenas caracteristicas de transferencia de masa para disenos compactos las torres empacadas con baja caida de presion. Este documento presenta los resultados de un estudio del comportamiento de un absorbedor de torre empacada para una solucion acuosa de desecante de cloruro de litio como sistema de deshumidificacion. El regimen de deshumidificacion asi como tambien la eficiencia del proceso de deshumidificacion se evaluo bajo los efectos de variables tales como regimenes de flujo de aire y de desecante, temperatura del aire y humedad, y concentracion y temperatura del desecante. Se uso una variante de modelo matematico de

  14. Extraction of amylase from fermentation broth in poly (Ethylene Glycol salt aqueous two-phase system

    Directory of Open Access Journals (Sweden)

    Raquel Pedrosa Bezerra

    2006-07-01

    Full Text Available Studies were carried out on the partition of amylase from Bacillus subtilis in a minimal medium at 37 ºC and 110 rpm. Enzyme recovery was carried out in aqueous two-phase system PEG-Phosphate salt were carried out. The best purification factor (5.4 was obtained in system PEG 1000 (16.7% w/w with potassium phosphate (14.8% w/w, at pH 6.0, resulting in a recovery of 45.2% activity enzymatic in the salt-rich phase.Enzimas amilolíticas têm sido amplamente investigadas com a finalidade de melhorar os processos industriais para a degradação do amido. Foi determinado que a extração da enzima em sistema bifásico aquosos é um método aplicável para separação e purificação de biomoléculas em misturas. Vários sistemas compostos de soluções aquosas de polietilenoglicol e fosfato foram avaliados. Estudos de produção em meio mínimo suplementado, à 37ºC, com uma velocidade de agitação de 110rpm e recuperação da amilase a partir do Bacillus subtilis em sistema bifásico aquoso PEG-fosfato foram avaliados. O melhor fator de purificação (5.4 foi obtido no sistema PEG 1000 (16.7% w/w com fosfato de potássio (14.8% w/w, a pH 6.0, resultando na recuperação da atividade enzimática de 45.2% na fase rica em sal.

  15. Theoretical Studies of Aqueous Systems above 25 deg C. 2. The Iron - Water System

    International Nuclear Information System (INIS)

    A theoretical study of the iron-water system at elevated temperatures is reported. Values for the equilibrium constants for the principle reactions in the system up to 374 deg C, obtained by a method described previously, are given and equilibrium diagrams are presented that illustrate the results for 50, 150, 250 and 350 deg C. The results indicate that, among other things, the most important metal-bearing ions in the iron-water system at elevated temperatures are Fe(OH)2+, Fe(OH)+ and HFeO2- The conditions for the stability of solid iron oxides are also examined. Finally, some limitations of the thermodynamic approach to corrosion problems are discussed briefly

  16. System for absolute measurement of electrolytic conductivity in aqueous solutions based on van der Pauw's theory

    International Nuclear Information System (INIS)

    Based on an innovative application of van der Pauw's theory, a system was developed for the absolute measurement of electrolytic conductivity in aqueous solutions. An electrolytic conductivity meter was designed that uses a four-electrode system with an axial–radial two-dimensional adjustment structure coupled to an ac voltage excitation source and signal collecting circuit. The measurement accuracy, resolution and repeatability of the measurement system were examined through a series of experiments. Moreover, the measurement system and a high-precision electrolytic conductivity meter were compared using some actual water samples. (paper)

  17. Radiation-induced reduction of metal ions in aqueous solution systems and its application

    International Nuclear Information System (INIS)

    Introduction: Promotion of chemical reactions by adding oxide particles to aqueous solution under the irradiation of ionizing radiations has been paid attention especially from the practical viewpoint, so that hydrogen production and decomposition of toxic organic compounds studied. On the other hand, redox of metal ions has not been studied very much since successive reactions after the redox become complicated due to equilibrium between reactant and product, and to transformation of dissolved species by varying pH and coexisting ions... In the present study, reduction behavior of metal ions in aqueous solution systems irradiated by r-ray and electron beam was measured, the reduced amount was compared with that by water radiolysis, and then the promotion of reduction by adding oxide particles was found out quantitatively. Experimental: Samples were prepared by dissolving metal salts (Ce(IV), Cr(VI), Pt(IV),...) in 0.4 mol/L sulfuric acid or 0.1 mol/l sodium perchlorate solution and then by adding 1-10 wt% oxide particles such as TiO2, Al2O3 or SiO2 to the solution. The irradiation of sample was made without stirring the particles in the solution mainly by using 60Co γ-ray source (dose rate: 1-30 kGy/h) at Takasaki Research Institute, JAEA; the absorbed dose of sample was estimated by using dosimeters of dichromate solution and/or CTA film. Just after irradiated, the sample was passed through a membrane filter to be separated into solution and solid components; absorption spectrum of metal ions in the solution was observed, and the reduced amount determined from difference in the absorbance before and after the irradiation. Results and discussion: Figure 1 shows absorption spectra of Ce(IV) ion in 0.4 mol/L H2SO4 solution under the γ-ray irradiation as typical results. Fig.1(a) illustrates that the reduction was observed in the solution without the oxide particles as stoichiometry in the one-electron reduction by water radiolysis has been used as a dosimeter, and

  18. An easily operated apparatus to register the amount of the aqueous solution absorbed by a plant root system

    Directory of Open Access Journals (Sweden)

    Jerzy Czerski

    2015-05-01

    Full Text Available An easily operated apparatus was constructed (figs. 1,2 allowing to register the amount of the aqueous solution absorbed by a planet root system. The device allows for simultaneous registering of the solution absorption by two plants. The recording of a definite volume of the absorbed solution can be controlled within wide limits. Experiments (figs. 3,4 confirmed the efficiency of the apparatus.

  19. Purification of C-phycocyanin from Spirulina platensis in aqueous two-phase systems using an experimental design

    OpenAIRE

    Francine Silva Antelo; Jorge Alberto Vieira Costa; Susana Juliano Kalil

    2015-01-01

    C-phycocyanin from Spirulina platensis was purified in aqueous two-phase systems (ATPS) of polyethylene glycol (PEG)/potassium phosphate, varying the molar mass of the PEG. Results using a full factorial design showed that an increase in the concentration of salt and decrease in the concentration of PEG caused an increment in the purification factor for all the ATPS studied. Optimization of the conditions of the purification was studied using a central composite rotatable design for each mola...

  20. Aqueous two-phase micellar systems in an oscillatory flow micro-reactor: Study of perspectives and experimental performance

    OpenAIRE

    A. M. LOPES; Silva, Daniel Pereira da; A.A. Vicente; Pessoa Júnior, Adalberto; Teixeira, J. A.

    2011-01-01

    Aqueous two-phase micellar systems (ATPMS) are micellar surfactant solutions with physical properties that make them very efficient for the extraction/concentration of biological products. In this work the main proposal that has been discussed is the possible applicability and importance of a novel oscillatory flow micro-reactor (micro-OFR) envisaged for parallel screening and/or development of industrial bioprocesses in ATPMS. Based on the technology of oscillatory flow mixing (OFM), this ba...

  1. Synthesis and NMR characterization of SAPO-35 from non-aqueous systems using hexamethyleneimine template

    International Nuclear Information System (INIS)

    SAPO-35 was synthesized using hexamethyleneimine template in non-aqueous systems. X-ray diffraction and scanning electron micrograph analysis shows the synthesized sample is pure and well crystalline. Presence of four stages (1.6%, 0.8%, 7.8% and 8.4%) of weight loss is observed by TG/DTA analysis. FT-IR analysis in the framework region shows the presence of tetrahedral T-O-T vibrations is similar to the other known aluminophosphate molecular sieves. FT-IR spectrum in the -OH region shows stretching vibrations at 3631, 3604 and 3580 cm-1 can be assigned to OH groups in bigger cages near S6R, in bigger cages near D6R and those actually confined inside the D6R, respectively. The spectra for the as-synthesized sample show a single symmetrical 27Al MAS NMR line at δ = 36.26 indicating the presence of a single tetrahedral aluminium species. Where as 29Si and 31P MAS NMR shows the presence of two peaks in both at (-89.9 and -95.15 ppm) and (-34.01 and -40.45 ppm) due to the Si substitution of P present in two different locations in double 6 ring (D6R) and in single 6 ring (S6R). 27Al 3Q-MAS NMR shows two peaks for environmentally different tetrahedral aluminium atoms. This is the first time we are showing such a fact which is not observable using ordinary MAS NMR

  2. Chromatography of 49 metal ions on stannic antimonate papers in dimethylsulfoxide: nitric acid systems and aqueous nitric acid systems

    International Nuclear Information System (INIS)

    Chromatographic separations of 49 metal ions on stannic antimonate papers have been performed using mixed solvent systems containing DMSO. Aqueous HNO3 systems have also been used. The utility of the papers has been demonstrated by achieving various difficult separations. Some of the important separations (R/sub f/ values given in parentheses) are: Cs+(0.20)-K+(0.30) and Sm3+(0.00)-Pr3+(0.72) in pure DMSO; Nb5+(0.14)-VO2+(0.95) in DMSO-6M HNO3 (1:1); Ti4+(0.00)-VO2(0.97) in DMSO-0.5M HNO3 (1:1); and Ba2+(0.06)-K+(0.52)-Sr2+(0.95), Ba2+(0.04)-Cs+(0.41)-Mg2+(0.93), and Ca2+(0.10)-Sr2+(0.94) in DMSO-0.1M HNO3 (1:1). The time of development in each case is two hours. A discussion is presented on the dependence of Ri, log R/sub f/, and R/sub M/ on pH of the solvent to understand the mechanism of the movement of metal ions on papers impregnated with inorganic materials. (U.S.)

  3. Structures and interactions in aqueous solutions and gels of thermoresponsive polymer systems

    Czech Academy of Sciences Publication Activity Database

    Spěváček, Jiří

    Dharwad: Karnatak University, Department of Chemistry, 2015. s. 25. [International Conference on Direct Digital Manufacturing and Polymers - ICDDMAP 2015. 28.10.2015-31.10.2015, Dharwad] R&D Projects: GA ČR(CZ) GA15-13853S Institutional support: RVO:61389013 Keywords : thermoresponsive polymers * aqueous solution * hydrogel Subject RIV: CD - Macromolecular Chemistry

  4. Exploiting donor-acceptor interactions in aqueous dynamic combinatorial libraries : exploratory studies of simple systems

    NARCIS (Netherlands)

    Au-Yeung, Ho Yu; Cougnon, Fabien B. L.; Otto, Sijbren; Pantos, G. Dan; Sanders, Jeremy K. M.; Pantoş, G. Dan

    2010-01-01

    The behaviour of aqueous dynamic combinatorial libraries (DCLs) containing either electron-rich donor building blocks based on dioxynaphthalene (DN), or electron-deficient acceptor building blocks based on naphthalenediimide (NDI) are described. The influence of concentration and ionic strength on l

  5. Novel aqueous chitosan-based dispersions as efficient drug delivery systems for topical use. Rheological, textural and release studies.

    Science.gov (United States)

    Lucero, M J; Ferris, C; Sánchez-Gutiérrez, C A; Jiménez-Castellanos, M R; de-Paz, M-V

    2016-10-20

    The use of a novel cross-linked thiolated chitosan (CTS) was investigated as the main component of aqueous dispersions (at 1% and 3% w/v) for topical drug delivery systems. The nonionic theophiline (Th) and the cationic diltiazem(.)HCl (Dt) (at 0.5% w/v concentration) were used as model drugs. All aqueous dispersions behaved as viscoelastic fluids. The CTS 1% dispersions showed predominance of viscous component and low viscosity. However, in the CTS 3% dispersions, both the elastic component and high viscosities prevailed. So, texture parameters improved from CTS 1% to 3% dispersions and CTS 3%-Dt showed greater cohesion and adhesion than CTS 3%-Th, but always below CTS alone. All dispersions showed a Fickian diffusion mechanism. Despite release profiles of both drugs almost fully overlapped at 1% CTS, diffusion coefficients confirmed Dt released faster than Th at 3% CTS. The rheological behavior and the chemical nature of the drugs explained these results. PMID:27474615

  6. Evaluation of Two Biosorbents in the Removal of Metal Ions in Aqueous Using a Pilot Scale Fixed-bed System

    Directory of Open Access Journals (Sweden)

    Andre Gadelha Oliveira

    2014-05-01

    Full Text Available The aim of the present work was to investigate the adsorption of toxic metal ions copper, nickel and zinc from aqueous solutions using low cost natural biomass (sugar cane bagasse and green coconut fiber in pilot scale fixed-bed system. The Hydraulic retention time (HRT was 229 minutes and the lowest adsorbent usage rate (AUR found was 0.10 g.L-1 for copper using green coconut fibers. The highest values of adsorption capacities founded were 1.417 and 2.772 mg.g-1 of Cu(II ions for sugarcane bagasse and green coconut fibers, respectively. The results showed that both sugarcane bagasse and green coconut fiber presented potential in the removal of metal ions copper, nickel and zinc ions from aqueous solution and the possible use in wastewater treatment station.

  7. Intervertebral Disc Tissue Engineering with Natural Extracellular Matrix-Derived Biphasic Composite Scaffolds.

    Directory of Open Access Journals (Sweden)

    Baoshan Xu

    Full Text Available Tissue engineering has provided an alternative therapeutic possibility for degenerative disc diseases. However, we lack an ideal scaffold for IVD tissue engineering. The goal of this study is to fabricate a novel biomimetic biphasic scaffold for IVD tissue engineering and evaluate the feasibility of developing tissue-engineered IVD in vitro and in vivo. In present study we developed a novel integrated biphasic IVD scaffold using a simple freeze-drying and cross-linking technique of pig bone matrix gelatin (BMG for the outer annulus fibrosus (AF phase and pig acellular cartilage ECM (ACECM for the inner nucleus pulposus (NP phase. Histology and SEM results indicated no residual cells remaining in the scaffold that featured an interconnected porous microstructure (pore size of AF and NP phase 401.4 ± 13.1 μm and 231.6 ± 57.2 μm, respectively. PKH26-labeled AF and NP cells were seeded into the scaffold and cultured in vitro. SEM confirmed that seeded cells could anchor onto the scaffold. Live/dead staining showed that live cells (green fluorescence were distributed in the scaffold, with no dead cells (red fluorescence being found. The cell-scaffold constructs were implanted subcutaneously into nude mice and cultured for 6 weeks in vivo. IVD-like tissue formed in nude mice as confirmed by histology. Cells in hybrid constructs originated from PKH26-labeled cells, as confirmed by in vivo fluorescence imaging system. In conclusion, the study demonstrates the feasibility of developing a tissue-engineered IVD in vivo with a BMG- and ACECM-derived integrated AF-NP biphasic scaffold. As well, PKH26 fluorescent labeling with in vivo fluorescent imaging can be used to track cells and analyse cell--scaffold constructs in vivo.

  8. Biphasic positive airway pressure ventilation (PeV+) in children

    OpenAIRE

    Jaarsma, Anneke S; Knoester, Hennie; van Rooyen, Frank; Bos, Albert P.

    2001-01-01

    Background: Biphasic positive airway pressure (BIPAP) (also known as PeV+) is a mode of ventilation with cycling variations between two continuous positive airway pressure levels. In adults this mode of ventilation is effective and is being accepted with a decrease in need for sedatives because of the ability to breathe spontaneously during the entire breathing cycle. We studied the use of BIPAP in infants and children. Methods: We randomized 18 patients with respiratory failure for ventilati...

  9. Internally consistent thermodynamic data for aqueous species in the system Na-K-Al-Si-O-H-Cl

    Science.gov (United States)

    Miron, George D.; Wagner, Thomas; Kulik, Dmitrii A.; Heinrich, Christoph A.

    2016-08-01

    A large amount of critically evaluated experimental data on mineral solubility, covering the entire Na-K-Al-Si-O-H-Cl system over wide ranges in temperature and pressure, was used to simultaneously refine the standard state Gibbs energies of aqueous ions and complexes in the framework of the revised Helgeson-Kirkham-Flowers equation of state. The thermodynamic properties of the solubility-controlling minerals were adopted from the internally consistent dataset of Holland and Powell (2002; Thermocalc dataset ds55). The global optimization of Gibbs energies of aqueous species, performed with the GEMSFITS code (Miron et al., 2015), was set up in such a way that the association equilibria for ion pairs and complexes, independently derived from conductance and potentiometric data, are always maintained. This was achieved by introducing reaction constraints into the parameter optimization that adjust Gibbs energies of complexes by their respective Gibbs energy effects of reaction, whenever the Gibbs energies of reactant species (ions) are changed. The optimized thermodynamic dataset is reported with confidence intervals for all parameters evaluated by Monte Carlo trial calculations. The new thermodynamic dataset is shown to reproduce all available fluid-mineral phase equilibria and mineral solubility data with good accuracy and precision over wide ranges in temperature (25-800 °C), pressure (1 bar to 5 kbar) and composition (salt concentrations up to 5 molal). The global data optimization process adopted in this study can be readily repeated any time when extensions to new chemical elements and species are needed, when new experimental data become available, or when a different aqueous activity model or equation of state should be used. This work serves as a proof of concept that our optimization strategy is feasible and successful in generating a thermodynamic dataset reproducing all fluid-mineral and aqueous speciation equilibria in the Na-K-Al-Si-O-H-Cl system within

  10. Characterization and biocompatibility of fluoridated biphasic calcium phosphate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Z.L. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Yu, H.Y. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)], E-mail: yhyang6812@tfol.com; Zeng, Q. [Institute for Nanobiomedical Technology and Membrane Biology, Sichuan University, Chengdu 610041 (China); He, H.W. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)

    2008-11-15

    Biphasic calcium phosphate ceramics (BCP) has been widely used in tooth and bone implants due to its excellent biocompatibility. Incorporation of fluorine ions in BCP has drawn much attention because of the beneficial role played by the fluorine ions in bone and tooth growth. The aim of this study was to obtain fluoridated biphasic calcium phosphate (FBCP) by immersing BCP into saturated ZnF{sub 2} solution with F{sup -} concentration of 3500 mg/l at different times. The phase and incorporation of fluoride into BCP were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The biomineralization and influence of FBCP on osteoblastic behavior were evaluated and compared with that of biphasic calcium phosphate (BCP). The results exhibited that the phase evolution of the BCP was affected by the fluoride incorporation and the FBCP significantly improved the differentiation and proliferation of osteoblasts. These findings suggest that the FBCP would be very useful as a bone reconstructive material.

  11. Kinetics of carbonate dissolution in CO2-saturated aqueous system at reservoir conditions

    Science.gov (United States)

    Peng, Cheng; Crawshaw, John P.; Maitland, Geoffrey; Trusler, J. P. Martin

    2014-05-01

    In recent years, carbon capture and storage (CCS) has emerged as a key technology for limiting anthropogenic CO2 emissions while allowing the continued utilisation of fossil fuels. The most promising geological storage sites are deep saline aquifers because the capacity, integrity and injection economics are most favourable, and the environmental impact can be minimal. Many rock-fluid chemical reactions are known to occur both during and after CO2 injection in saline aquifers. The importance of rock-fluid reactions in the (CO2 + H2O) system can be understood in terms of their impact on the integrity and stability of both the formation rocks and cap rocks. The chemical interactions between CO2-acidified brines and the reservoir minerals can influence the porosity and permeability of the formations, resulting in changes in the transport processes occurring during CO2 storage. Since carbonate minerals are abundant in sedimentary rocks, one of the requirements to safely implement CO2 storage in saline aquifers is to characterise the reactivity of carbonate minerals in aqueous solutions at reservoir conditions. In this work, we reported measurements of the intrinsic rate of carbonate dissolution in CO2-saturated water under high-temperature high-pressure reservoir conditions extending up to 373 K and 14 MPa. The rate of carbonate dissolution in CO2-free HCl(aq) was also measured at ambient pressure at temperatures up to 353 K. Various pure minerals and reservoir rocks were investigated in this study, including single-crystals of calcite and magnesite, and samples of dolomite, chalks and sandstones. A specially-designed batch reactor system, implementing the rotating disc technique, was used to obtain the intrinsic reaction rate at the solid/liquid interface, free of mass transfer effects. The effective area and mineralogy of the exposed surface was determined by a combination of surface characterisation techniques including XRD, SEM, EDX and optical microscopy. The

  12. Design and development of single stage purification of papain using Ionic Liquid based aqueous two phase extraction system and its Partition coefficient studies

    OpenAIRE

    Senthilkumar Rathnasamy; R.Kumaresan2

    2013-01-01

    As an emerging trend in bioseparation, aqueous two phase extractions based on phosponium ionic liquid have been utilized in this work to extract papain from Carica papaya fruit latex and the same wascompared with conventional aqueous two phase extraction system. Factors affecting the partition coefficient of papain such as ionic liquid concentration, pH of the extraction system and temperature have been investigated. The optimization studies show that ionic liquid concentrations and pH are ma...

  13. Investigation of heterogenous equilibria in uranoborate MII(BUO5)2·nH2O - aqueous solution system (MII=Mn, Co, Ni, Zn)

    International Nuclear Information System (INIS)

    State of uranoborates of MII(BUO5)2·nH2O (MII=Mn, Co, Ni, Zn) series in aqueous solutions of inorganic acid at 25 Deg C is investigated. Using experimental data on uranoborate solubility in hydrochloric acid a quantitative model of the system uranoborate - aqueous solution is proposed. The model is used for forecasting of states of heterogenous systems in different conditions and for calculation of standard thermodynamic functions of uranoborates

  14. Biphasic products of dicalcium phosphate-rich cement with injectability and nondispersibility

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Chia-Ling [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, Feng Chia University, Taichung, 407, Taiwan (China); Dental Medical Devices and Materials Research Center, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Chen, Jian-Chih [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Department of Orthopaedics, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Hung, Chun-Cheng; Wang, Jen-Chyan [Dental Medical Devices and Materials Research Center, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Tien, Yin-Chun [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Department of Orthopaedics, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, Feng Chia University, Taichung, 407, Taiwan (China)

    2014-06-01

    In this study, a calcium phosphate cement was developed using tetracalcium phosphate and surface-modified dicalcium phosphate anhydrous (DCPA). This developed injectable bone graft substitute can be molded to the shape of the bone cavity and set in situ through the piping system that has an adequate mechanical strength, non-dispersibility, and biocompatibility. The materials were based on the modified DCPA compositions of calcium phosphate cement (CPC), where the phase ratio of the surface-modified DCPA is higher than that of the conventional CPC for forming dicalcium phosphate (DCP)-rich cement. The composition and morphology of several calcium phosphate cement specimens during setting were analyzed via X-ray diffractometry and transmission electron microscopy coupled with an energy dispersive spectroscopy system. The compressive strength of DCP-rich CPCs was greater than 30 MPa after 24 h of immersion in vitro. The reaction of the CPCs produced steady final biphasic products of DCPs with apatite. The composites of calcium phosphate cements derived from tetracalcium phosphate mixed with surface-modified DCPA exhibited excellent mechanical properties, injectability, and interlocking forces between particles, and they also featured nondispersive behavior when immersed in a physiological solution. - Highlights: • Bone cement precursor with nanocrystals is characterized. • DCP-rich CPCs with nanocrystals exhibited biphasic product phases. • Nanocrystals in cement significantly affected the interlocking ability. • Nanocrystals in cement exhibited higher strength and anti-dispersion. • DCP-rich CPCs increase the potential of bioresorption after reaction.

  15. Biphasic products of dicalcium phosphate-rich cement with injectability and nondispersibility

    International Nuclear Information System (INIS)

    In this study, a calcium phosphate cement was developed using tetracalcium phosphate and surface-modified dicalcium phosphate anhydrous (DCPA). This developed injectable bone graft substitute can be molded to the shape of the bone cavity and set in situ through the piping system that has an adequate mechanical strength, non-dispersibility, and biocompatibility. The materials were based on the modified DCPA compositions of calcium phosphate cement (CPC), where the phase ratio of the surface-modified DCPA is higher than that of the conventional CPC for forming dicalcium phosphate (DCP)-rich cement. The composition and morphology of several calcium phosphate cement specimens during setting were analyzed via X-ray diffractometry and transmission electron microscopy coupled with an energy dispersive spectroscopy system. The compressive strength of DCP-rich CPCs was greater than 30 MPa after 24 h of immersion in vitro. The reaction of the CPCs produced steady final biphasic products of DCPs with apatite. The composites of calcium phosphate cements derived from tetracalcium phosphate mixed with surface-modified DCPA exhibited excellent mechanical properties, injectability, and interlocking forces between particles, and they also featured nondispersive behavior when immersed in a physiological solution. - Highlights: • Bone cement precursor with nanocrystals is characterized. • DCP-rich CPCs with nanocrystals exhibited biphasic product phases. • Nanocrystals in cement significantly affected the interlocking ability. • Nanocrystals in cement exhibited higher strength and anti-dispersion. • DCP-rich CPCs increase the potential of bioresorption after reaction

  16. Modeling of aqueous and organic phase speciation for solvent extraction systems

    International Nuclear Information System (INIS)

    The TRUEX (TRansUranic EXtraction) solvent extraction process has the ability to remove, separate, and recover transuranic (TRU) elements from acidic nuclear waste solutions. A computer model of the TRUEX process is currently being developed for use in flowsheet design and process optimization. The correlations that are to be used in the model for generating extraction distribution ratios are based on chemical mass action principles and require calculation of aqueous and organic phase speciation. Aqueous phase activity coefficients are calculated using methods available in the literature, while the organic phase species are treated in terms of ideal associated solution theory. This approach is demonstrated for the extraction of HNO3, HTcO4, and americium nitrate by n-octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO)---the primary metal extractant in the TRUEX solvent. 23 refs., 5 figs

  17. Theoretical Studies of Aqueous Systems above 25 deg C. 1. Fundamental Concepts for Equilibrium Diagrams and some General Features of the Water System

    International Nuclear Information System (INIS)

    The illustration of thermodynamic data on aqueous systems is discussed and diagrams are described that are useful for bringing together the large numbers of data that are relevant to technological problems such as corrosion, mass-transport and deposition. Two kinds of logarithmic equilibrium diagram are particularly useful, namely, diagrams depicting the variation with pH or pe of the concentrations of ionic species relative to that of a chosen reference ion and diagrams depicting the fields of conditions of pH and pe in which the various species in any given system predominate or are stable. Such diagrams clearly and concisely illustrate the data and greatly simplify the comparison of the states of a system at different temperatures. Estimates of the equilibrium constants for the redox and the acid-base dissociation of water up to 375 C are reported and some general features of aqueous systems at elevated temperatures are discussed

  18. The decomposition yields and reactivity of metal tetrasulfophthalocyanines in aqueous-alcohol system

    International Nuclear Information System (INIS)

    The effect of gamma radiation on metal (Rh, Mn, Co, Ni and Cu) tetrasulfophthalocyanines in aqueous and water:methanol solutions have been studied. The determined yields of the complex decomposition (measured on the basis of absorption decays) decrease with the increase of the dose and depend on the composition of the matrix. The rate constants of radical scavenging have been determined applying the competition method with p-nitrosodimethylaniline

  19. Temperature-induced phase transition in aqueous solutions and gels of multicomponent polymer systems

    Czech Academy of Sciences Publication Activity Database

    Spěváček, Jiří; Konefal, Rafal; Dybal, Jiří

    Kolkata : Indian Association for the Cultivation of Science, 2016. s. 48-49. [International IUPAC Conference on Polymer -Solvent Complexes and Intercalates /11./ - POLYSOLVAT-11. 27.01.2016-30.01.2016, Kolkata] R&D Projects: GA ČR(CZ) GA15-13853S Institutional support: RVO:61389013 Keywords : temperature-induced phase transition * aqueous solution * hydrogel Subject RIV: CD - Macromolecular Chemistry

  20. Aqueous two-phase systems: an efficient, environmentally safe and economically viable method for purification of natural dye carmine.

    Science.gov (United States)

    Mageste, Aparecida Barbosa; de Lemos, Leandro Rodrigues; Ferreira, Guilherme Max Dias; da Silva, Maria do Carmo Hespanhol; da Silva, Luis Henrique Mendes; Bonomo, Renata Cristina Ferreira; Minim, Luis Antonio

    2009-11-01

    Partition of the natural dye carmine has been studied in aqueous two-phase systems prepared by mixing aqueous solutions of polymer or copolymer with aqueous salt solutions (Na(2)SO(4) and Li(2)SO(4)). The carmine dye partition coefficient was investigated as a function of system pH, polymer molar mass, hydrophobicity, system tie-line length and nature of the electrolyte. It has been observed that the carmine partition coefficient is highly dependent on the electrolyte nature and pH of the system, reaching values as high as 300, indicating the high potential of the two-phase extraction with ATPS in the purification of carmine dye. The partition relative order was Li(2)SO(4)"Na(2)SO(4). Carmine molecules were concentrated in the polymer-rich phase, indicating an enthalpic specific interaction between carmine and the pseudopolycation, which is formed by cation adsorption along the macromolecule chain. When the enthalpic carmine-pseudopolycation interaction decreases, entropic forces dominate the natural dye-transfer process, and the carmine partitioning coefficient decreases. The optimization of the extraction process was obtained by a central composite face-centered (CCF) design. The CCF design was used to evaluate the influence of Li(2)SO(4) and PEO 1500 concentration and of the pH on the partition coefficient of carmine. The conditions that maximize the partition of carmine into the top phase were determined to be high concentrations of PEO and Li(2)SO(4) and low pH values within the ranges studied. PMID:19800067

  1. Partition of synaptic membranes in aqueous two-phase systems at subzero temperatures by using anti-freeze solvent.

    Science.gov (United States)

    Johansson, G; Joelsson, M; Olde, B

    1990-11-16

    The freezing point of aqueous two-phase (liquid-liquid) systems containing water, dextran and poly(ethylene glycol) has been lowered by including glycerol. Biological membranes, obtained by fragmentation of a crude synaptosomal preparation from calf brain cortex, have been included in the two-phase systems. The effects of temperature and the concentration of glycerol on the partition of the membranes within the systems have been investigated. Considerable stabilisation of the membranes was noticed when they were partitioned at -10 degrees C compared with 0 degrees C. The influences of glycerol, ethylene glycol, N,N-dimethylformamide and tetrahydrofuran on the phase-forming properties of the systems and on enzyme activities are also presented. Possible use of the above systems for studies and separation of biological membranes are discussed. PMID:2245213

  2. Investigation of heterogeneous equilibria in the system uranosilicate MHSiUO6·nH2O - aqueous solvent (M=Li, Na, K)

    International Nuclear Information System (INIS)

    State of mineral-like compounds of MHSiUO6·nH2O (M=Li, Na, K) composition in aqueous solutions at 298 K is investigated. Taking experimental data on solubility as a basis quantitative model of the system crystalline uranosilicate - aqueous solution is proposed. This model could be a basis for calculation of Gibbs formation functions and solubility product. Gibbs formation functions of silicic acid and other ionic-molecular forms of existence of Si(IV) in solution are calculated. Using the proposed model solubility of uranosilicates in aqueous solutions (in the region, which are not investigated experimentally) is forecasted

  3. Biphasic electrical currents stimulation promotes both proliferation and differentiation of fetal neural stem cells.

    Directory of Open Access Journals (Sweden)

    Keun-A Chang

    Full Text Available The use of non-chemical methods to differentiate stem cells has attracted researchers from multiple disciplines, including the engineering and the biomedical fields. No doubt, growth factor based methods are still the most dominant of achieving some level of proliferation and differentiation control--however, chemical based methods are still limited by the quality, source, and amount of the utilized reagents. Well-defined non-chemical methods to differentiate stem cells allow stem cell scientists to control stem cell biology by precisely administering the pre-defined parameters, whether they are structural cues, substrate stiffness, or in the form of current flow. We have developed a culture system that allows normal stem cell growth and the option of applying continuous and defined levels of electric current to alter the cell biology of growing cells. This biphasic current stimulator chip employing ITO electrodes generates both positive and negative currents in the same culture chamber without affecting surface chemistry. We found that biphasic electrical currents (BECs significantly increased the proliferation of fetal neural stem cells (NSCs. Furthermore, BECs also promoted the differentiation of fetal NSCs into neuronal cells, as assessed using immunocytochemistry. Our results clearly show that BECs promote both the proliferation and neuronal differentiation of fetal NSCs. It may apply to the development of strategies that employ NSCs in the treatment of various neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases.

  4. Online Epileptic Seizure Prediction Using Wavelet-Based Bi-Phase Correlation of Electrical Signals Tomography.

    Science.gov (United States)

    Vahabi, Zahra; Amirfattahi, Rasoul; Shayegh, Farzaneh; Ghassemi, Fahimeh

    2015-09-01

    Considerable efforts have been made in order to predict seizures. Among these methods, the ones that quantify synchronization between brain areas, are the most important methods. However, to date, a practically acceptable result has not been reported. In this paper, we use a synchronization measurement method that is derived according to the ability of bi-spectrum in determining the nonlinear properties of a system. In this method, first, temporal variation of the bi-spectrum of different channels of electro cardiography (ECoG) signals are obtained via an extended wavelet-based time-frequency analysis method; then, to compare different channels, the bi-phase correlation measure is introduced. Since, in this way, the temporal variation of the amount of nonlinear coupling between brain regions, which have not been considered yet, are taken into account, results are more reliable than the conventional phase-synchronization measures. It is shown that, for 21 patients of FSPEEG database, bi-phase correlation can discriminate the pre-ictal and ictal states, with very low false positive rates (FPRs) (average: 0.078/h) and high sensitivity (100%). However, the proposed seizure predictor still cannot significantly overcome the random predictor for all patients. PMID:26126613

  5. Control of phase composition in hydroxyapatite/tetracalcium phosphate biphasic thin coatings for biomedical applications

    OpenAIRE

    Kim, H.; CAMATA, R. P.; Vohra, Y. K.; LACEFIELD, W. R.

    2005-01-01

    Biphasic calcium phosphates comprising well-controlled mixtures of nonresorbable hydroxyapatite and other resorbable calcium phosphate phases often exhibit a combination of enhanced bioactivity and mechanical stability that is difficult to achieve in single-phase materials. This makes these biphasic bioceramics promising substrate materials for applications in bone tissue regeneration and repair. In this paper we report the synthesis of highly crystalline, biphasic coatings of hydroxyapatite/...

  6. Liquid-Liquid Equilibria of Aqueous Two-phase Systems Containing Polyethylene Glycol 4000 and Two Different Salts of Ammonium

    Directory of Open Access Journals (Sweden)

    G. Khayati

    2011-02-01

    Full Text Available The aim of this study was to survey on phase diagrams and Liquid-Liquid Equilibrium (LLE data of the aqueous PEG4000 - (NH42HPO4 and PEG4000 - (NH42SO4 systems experimentally at 298.15 K. The salting-out effect was also discussed on the basis of the Gibbs free energy of hydration of ions. The experimental binodal data were satisfactorily correlated with the Merchuk equation. Tie line compositions were correlated using the Othmer-Tobias and Bancroft equations, and the parameters have also reported. Good agreement was obtained with the experimental data with the model equations.

  7. Thermodynamic modelling of phase equilibrium for water + poly(Ethylene glycol + salt aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    R.A.G. Sé

    2002-04-01

    Full Text Available The NRTL (nonrandom, two-liquid model, expressed in mass fraction instead of mole fraction, was used to correlate liquid-liquid equilibria for aqueous two-phase polymer-salt solutions. New interaction energy parameters for this model were determined using reported data on the water + poly(ethylene glycol + salt systems, with different molecular masses for PEG and the salts potassium phosphate, sodium sulfate, sodium carbonate and magnesium sulfate. The correlation of liquid-liquid equilibrium is quite satisfactory.

  8. Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts

    OpenAIRE

    Adalberto Pessoa Junior; Hans-Olof Johansson; Eloi Feitosa

    2011-01-01

    Aqueous two-phase systems consisting of polyethylene glycol (PEG), sodium polyacrylate (NaPAA), and a salt have been studied. The effects of the polymer size, salt type (NaCl, Na2SO4, sodium adipate and sodium azelate) and salt concentrations on the position of the binodal curve were investigated. The investigated PEG molecules had a molar mass of 2,000 to 8,000 g/mol, while that of NaPAA was 8,000 g/mol. Experimental phase diagrams, and tie lines and calculated phase diagrams, based on Flory...

  9. Recent Results of the Investigation of a Microfluidic Sampling Chip and Sampling System for Hot Cell Aqueous Processing Streams

    Energy Technology Data Exchange (ETDEWEB)

    Julia Tripp; Jack Law; Tara Smith

    2013-10-01

    A Fuel Cycle Research and Development project has investigated an innovative sampling method that could evolve into the next generation sampling and analysis system for metallic elements present in aqueous processing streams. Initially sampling technologies were evaluated and microfluidics sampling chip technology was selected and tested. A conceptual design for a fully automated microcapillary-based system was completed and a robotic automated sampling system was fabricated. The mechanical and sampling operation of the completed sampling system was investigated. In addition, the production of a less expensive, mass produced sampling chip was investigated to avoid chip reuse thus increasing sampling reproducibility/accuracy. The microfluidic-based robotic sampling system’s mechanical elements were tested to ensure analytical reproducibility and the optimum robotic handling of microfluidic sampling chips.

  10. Early solar system aqueous activity - Sr isotope evidence from the Orgueil CI meteorite

    Science.gov (United States)

    Macdougall, J. D.; Lugmair, G. W.; Kerridge, J. F.

    1984-01-01

    The Sr isotopic composition and Rb-87/Sr-86 ratio have been measured in carbonates and sulfate separated from the Orgueil meteorite in order to determine the time when liquid water may have acted on the parent body. Both of the studied phases probably precipitated from aqueous solution. The results show that carbonate deposition occurred contemporaneously with parent body formation or shortly after it, probably within 100 Myr. On the other hand, at least some of the calcium sulfate seems to have been formed recently.

  11. Potential of Rice Husk and Rice Husk Ash for Phenol Removal in Aqueous Systems

    OpenAIRE

    A.H Mahvi; Maleki, A.; A. Eslami

    2004-01-01

    The potential of rice husk and rice husk ash for phenol adsorption from aqueous solution was studied. Batch kinetics and isotherm studies were carried out under varying experimental conditions of contact time, phenol concentration, adsorbent dose and pH. Adsorption equilibrium of rice husk and rice husk ash was reached within 6 hours for phenolic concentration 150-500 μg/L and 3 hours for phenol concentration 500-1300 μg/L, respectively. Kinetics of adsorption obeyed a first-order rate equa...

  12. Immobilization of lipase on sepabeads and its application in pentyl octanoate synthesis in a low aqueous system

    Directory of Open Access Journals (Sweden)

    Knežević-Jugović Zorica D.

    2008-01-01

    Full Text Available The object of the study was to investigate the process conditions relevant for the pentyl octanoate production with the lipase from Candida rugosa immobilized on Sepabeads EC-EP carrier. This is an epoxide-containing commercial polymethacrylic carrier with suitable characteristics for enzyme immobilization. The immobilized lipase suitable for pentyl octanoate synthesis has been prepared by a direct lipase binding to polymers via their epoxide groups. The enzymatic activity was determined by both hydrolysis of olive oil in an aqueous system and esterification of n-pentanol with octanoic acid in a low aqueous system. The influence of several important reaction parameters such as temperature, initial water content, initial substrate molar ratio, enzyme loading and time of adding of molecular sieves in the system is carefully analyzed by means of an experimental design. Production of the ester was optimized and an ester production response equation was obtained, making it possible to predict ester yields from known values of the five main factors. Almost complete conversion (>99% of the substrate to ester could be realized, using lipase loading as low as 37 mg/g dry support and in a relatively short time (24 h at 45ºC, when high initial substrate molar ratio of 2.2 is used.

  13. Biphasic dissolution method for quality control and assurance of drugs containing active substances in the form of weak acid salts.

    Science.gov (United States)

    Franc, Aleš; Muselłk, Jan; Goněc, Roman; Vetchý, David

    2016-03-01

    Substances in the form of weak acid salts have been found to be problematic for dissolution testing. Their absorption can start only after they are turned into the form of an acid following the gastric passage although they were administered in the form of a salt. Due to poor solubility, they cannot be tested in acidic gastric environment for a biased dissolution profile. The biphasic dissolution method is promising for overcoming this obstacle. Tablets with warfarin clathrate sodium salt in two concentrations and two different particle size distributions were tested as a suitable model for finding the medium and process conditions of dissolution. The dissolution method based on the use of the upper organic layer (1-octanol) and the lower aqueous layer 0.1 mol L-1 HCl) was found suitable and discriminatory for tablets containing active substances in the form of salts of weak acids. The method also reflects physical differences in the quality of used substances. PMID:26959550

  14. Molecular dynamics simulations on aqueous two-phase systems - Single PEG-molecules in solution

    Directory of Open Access Journals (Sweden)

    Oelmeier Stefan A

    2012-08-01

    Full Text Available Abstract Background Molecular Dynamics (MD simulations are a promising tool to generate molecular understanding of processes related to the purification of proteins. Polyethylene glycols (PEG of various length are commonly used in the production and purification of proteins. The molecular mechanisms behind PEG driven precipitation, aqueous two-phase formation or the effects of PEGylation are however still poorly understood. Results In this paper, we ran MD simulations of single PEG molecules of variable length in explicitly simulated water. The resulting structures are in good agreement with experimentally determined 3D structures of PEG. The increase in surface hydrophobicity of PEG of longer chain length could be explained on an atomic scale. PEG-water interactions as well as aqueous two-phase formation in the presence of PO4 were found to be correlated to PEG surface hydrophobicity. Conclusions We were able to show that the taken MD simulation approach is capable of generating both structural data as well as molecule descriptors in agreement with experimental data. Thus, we are confident of having a good in silico representation of PEG.

  15. Central nervous system activity of an aqueous acetonic extract of Ficus carica L. in mice

    Directory of Open Access Journals (Sweden)

    Mittal M Bhanushali

    2014-01-01

    Full Text Available Background: Ficus carica Linn. is reported to possess variety of activities, but its potential in CNS disorders is still to be explored. Objective: The present study was carried out to evaluate the CNS depressant activity of aqueous acetonic extract of Ficus carica Linn on different models in mice. Materials and Methods: The aerial parts of the plant Ficus carica L. were extracted with aqueous acetone and the solvent was removed by rotary vacuum evaporator under reduced pressure. A crude extract was given orally and its effects were tested on ketamine-induced sleeping time, muscle-coordination, anxiety (elevated-plus maze and Staircase test, convulsions [maximal electroshock (MES and pentylenetetrazole (PTZ-induced seizures], and nociception. In addition, we determined the levels of neurotransmitters, norepinephrine (NE and 5-hydroxytryptamine (5-HT. Results: Results from the experimental models tested showed: (1 a delay on onset and prolongation of sleep of ketamine-induced sleeping time; (2 significant muscle relaxant activity; (3 a significant attenuation in the anxiety-response (4 a delay in the onset of seizures and reduction in duration of seizures and mortality induced by MES and PTZ; (5 a reduction in the licking time in nociception test and (6 increased levels of NE and 5-HT. Conclusion: This suggests that Ficus carica L. exerts its CNS depressive effect by modulating the neurotransmitters NE and 5-HT in the brain.

  16. Biphasic synovial sarcoma in the cervical spine: Case report

    OpenAIRE

    Foreman Stephen M; Stahl Michael J

    2011-01-01

    Abstract Synovial sarcoma is a rare malignant neoplasm of soft tissue that typically arising near large joints of the upper and lower extremities in young adult males. Only 3% of these neoplasms have been found to arise in the head and neck region. To our knowledge, there are limited reports in the literature of this neoplasm in the cervical spine. A case of biphasic synovial sarcoma of the cervical spine is reviewed. A 29 year-old male presented with pain on the left side of the cervical spi...

  17. Macrophage and osteoblast responses to biphasic calcium phosphate microparticles.

    Science.gov (United States)

    Fellah, Borhane Hakim; Delorme, Bruno; Sohier, Jérôme; Magne, David; Hardouin, Pierre; Layrolle, Pierre

    2010-06-15

    The aim of this work was to investigate in vitro the biological events leading to ectopic bone formation in contact with microporous biphasic calcium phosphate (BCP) ceramics. After implantation, microparticles may arise from their degradation and induce an inflammatory response involving macrophages. The secretion of pro-inflammatory cytokines may affect the differentiation of osteoblasts. Mouse macrophage-like (J774) and osteoblast-like (MC3T3-E1) cells were cultured in the presence of BCP microparticles of different sizes (response initiated by BCP microparticles may have both detrimental and beneficial effects on osteogenesis. PMID:20014296

  18. The biphasic response of rat vesical smooth muscle to ATP.

    OpenAIRE

    Bolego, C; Pinna, C.; Abbracchio, M. P.; Cattabeni, F.; Puglisi, L.

    1995-01-01

    1. Adenosine-5'-triphosphate (ATP) is known to exert a variety of biological effects via the activation of either ionotropic P2x- or G-protein coupled P2Y-purinoceptor subtypes. In this study the effects induced by ATP and ATP analogues on rat bladder strips were characterized at resting tone and in carbachol-prestimulated tissues. 2. ATP exerted a clear concentration-dependent biphasic response, which was maximal at 1 mM concentration and was characterized by an immediate and transient contr...

  19. Effects of organic acids, amino acids and ethanol on the radio-degradation of patulin in an aqueous model system

    International Nuclear Information System (INIS)

    The effects of organic acids, amino acids, and ethanol on the radio-degradation of patulin by gamma irradiation in an aqueous model system were investigated. The patulin, dissolved in distilled water at a concentration of 50 ppm, was practically degraded by the gamma irradiation at the dose of 1.0 kGy, while 33% of the patulin remained in apple juice. In the aqueous model system, the radio-degradation of patulin was partially inhibited by the addition of organic acids, amino acids, and ethanol. The proportions of remaining patulin after irradiation with the dose of 1.0 kGy in the 1% solution of malic acid, citric acid, lactic acid, acetic acid, ascorbic acid, and ethanol were 31.4%, 2.3%, 31.2%, 6.1%, 50.8%, and 12.5%, respectively. During 30 days of storage, the remaining patulin was reduced gradually in the solution of ascorbic acid and malic acid compared to being stable in other samples. The amino acids, serine, threonine, and histidine, inhibited the radio-degradation of patulin. In conclusion, it was suggested that 1 kGy of gamma irradiation (recommended radiation doses for radicidation and/or quarantine in fruits) is effective for the reduction of patulin, but the nutritional elements should be considered because the radio-degradation effects are environment dependent

  20. Mixed system of ionic liquid and non-ionic surfactants in aqueous media: Surface and thermodynamic properties

    International Nuclear Information System (INIS)

    Highlights: • Interaction of ionic liquid and ethylene oxide based non-ionic surfactants in aqueous media. • Evaluation of various surface properties and thermodynamic parameters. • Micellar growth ensues from exothermic to endothermic with increase in temperature. • Micelle formation is enthalpy driven at low temperature and entropy driven at higher temperature. • The micellization power and adsorption proficiency decreased at high IL concentrations. - Abstract: The mixed system of ionic liquid (IL) tetraethyl ammonium tetrafluoroborate [TEA(BF4)] and numerous ethylene oxide based non-ionic surfactants in aqueous media were studied using surface tension, viscosity and dynamic light scattering (DLS) measurements. Various surface properties like critical micelle concentration (cmc), maximum surface excess concentration (Γmax), minimum surface area per surfactant molecule (Amin), surface tension at the cmc (γcmc), adsorption efficiency (pC20), and effectiveness of surface tension reduction (πcmc) as well as thermodynamic parameters of micellization have been determined. DLS and viscosity measurements revealed that the micellar growth was attributed to the bridged solvophilicity of the POE chain in surfactants at elevated temperatures. In most of the cases, the progression ensues from exothermic to endothermic with increase in temperature of the mixed system. Thermodynamic parameter indicates that the micelle formation process is enthalpy driven at low temperature and entropy driven at higher temperature

  1. Effects of organic acids, amino acids and ethanol on the radio-degradation of patulin in an aqueous model system

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyejeong [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Chonbuk, Jeongeup 580-185 (Korea, Republic of); Department of Food Science and Technology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Lim, Sangyong [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Chonbuk, Jeongeup 580-185 (Korea, Republic of); Jo, Cheorun [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Chung, Jinwoo [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Chonbuk, Jeongeup 580-185 (Korea, Republic of); Kim, Soohyun [Glycomics Team, Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of); Kwon, Joong-Ho [Department of Food Science and Technology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Dongho [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Chonbuk, Jeongeup 580-185 (Korea, Republic of)], E-mail: fungikim@kaeri.re.kr

    2008-06-15

    The effects of organic acids, amino acids, and ethanol on the radio-degradation of patulin by gamma irradiation in an aqueous model system were investigated. The patulin, dissolved in distilled water at a concentration of 50 ppm, was practically degraded by the gamma irradiation at the dose of 1.0 kGy, while 33% of the patulin remained in apple juice. In the aqueous model system, the radio-degradation of patulin was partially inhibited by the addition of organic acids, amino acids, and ethanol. The proportions of remaining patulin after irradiation with the dose of 1.0 kGy in the 1% solution of malic acid, citric acid, lactic acid, acetic acid, ascorbic acid, and ethanol were 31.4%, 2.3%, 31.2%, 6.1%, 50.8%, and 12.5%, respectively. During 30 days of storage, the remaining patulin was reduced gradually in the solution of ascorbic acid and malic acid compared to being stable in other samples. The amino acids, serine, threonine, and histidine, inhibited the radio-degradation of patulin. In conclusion, it was suggested that 1 kGy of gamma irradiation (recommended radiation doses for radicidation and/or quarantine in fruits) is effective for the reduction of patulin, but the nutritional elements should be considered because the radio-degradation effects are environment dependent.

  2. Chelate-Modified Fenton Reaction for the Degradation of Trichloroethylene in Aqueous and Two-Phase Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Scott [Univ of KY, dept of chemical and materials engineering; lynch, Andrew [Univ of KY, dept of chemical and materials engineering; Bachas, Leonidas [Univ of KY, Dept of Chemistry; hampson, Steve [Univ of KY Center for Applied Energy Research - KY Research Consortium of Energy and Environment; Ormsbee, Lindelle [Univ of KY Center for Applied Energy Research - KY Research Consortium of Energy and Environment; Bhattacharyya, Dibakar [Univ of KY, dept of chemical and materials engineering

    2008-06-01

    The Standard Fenton reaction has been used for In-Situ Chemical Oxidation (ISCO) of toxic organics in groundwater. However, it requires low pH operating conditions, and thus has limitations for in situ applications. In addition, hydroxyl radicals are rapidly consumed by hydroxyl scavengers found in the subsurface. These problems are alleviated through the chelate-modified Fenton (hydroxyl radical) reaction, which includes the addition of nontoxic chelate (L) such as citrate or gluconic acid. This chelate allows the reaction to take place at bear neutral pH and control hydrogen peroxide consumption by binding to Fe(II), forming an FeL complex. The chelate also binds to Fe(III), preventing its precipitation as ferric hydroxide and thus prevents problems associated with injection well plugging. The rate of TCE dechlorination in chelate-modified Fenton systems is a function of pH, H2O2 concentration, and FE:L ratio. The primary objective of this research is to model and apply this process to the destruction of trichloroethylene (TCE) present in both the aqueous and organic (in the form of droplets) phases. Experimentation proved the chelate-modified Fenton reaction effectively dechlorinates TCE in both the aqueous and organic phases at near-neutral pH. Other focuses of this work include determining the effect of [L]:[Fe] ratios on H2O2 and TCE degradation as well as reusability of the FE citrate solution under repeated H2O2 injections. Generalized models were developed to predict the concentration of TCE in the aqueous phase and TCE droplet radius as a function of time using established hydroxyl radial kinetics and mass transfer relationships.

  3. Perchlorate production by ozone oxidation of chloride in aqueous and dry systems

    International Nuclear Information System (INIS)

    Overwhelming evidence now exists that perchlorate is produced through natural processes and can be ubiquitously found at environmentally relevant concentrations in arid and semi-arid locations. A number of potential production mechanisms have been hypothesized and ClO4- production by ozone oxidation of surface bound Cl- was demonstrated. However, no information concerning the impact of concentration, final reaction products distribution, impact of reaction phase, or oxidation of important oxychlorine intermediates has been reported. Using IC-MS-MS analysis and replicate oxidation experiments, we show that exposing aqueous solutions or Cl- coated sand or glass surfaces to O3 (0.96%) generated ClO4- with molar yields of 0.007 and 0.01% for aqueous Cl- solutions and 0.025 and 0.42% for Cl- coated sand and glass, respectively. Aqueous solutions of Cl- produced less ClO4- than Cl- coated sand or glass as well as a higher ratio of ClO3- to ClO4-. Reduction of the initial Cl- mass resulted in substantially higher molar yields of ClO4- and ClO3-. In addition, alkaline absorbers that captured gaseous products contained substantial quantities of Cl-, ClO3-, and ClO4-. Solutions of possible oxychlorine intermediates (OCl- and ClO3-) exposed to O3 produced only scant amounts of ClO4- while a ClO2- solution exposed to O3 produced substantial molar yields of ClO4- (4% molar yield). Scanning electron microscopy coupled with energy energy-dispersive X-ray analysis demonstrated a significant loss of Cl- and an increase in oxygen on the Cl- coated silica sand exposed to O3. While the experimental conditions are not reflective of natural conditions this work clearly demonstrates the relative potential of Cl- precursors in perchlorate production and the likely importance of dry aerosol oxidation over solution phase reactions. It also suggests that ClO2- may be a key intermediate while ClO3- and OCl- are unlikely to play a significant role

  4. Natural gas hydrate formation and inhibition in gas/crude oil/aqueous systems

    DEFF Research Database (Denmark)

    Daraboina, Nagu; Pachitsas, Stylianos; von Solms, Nicolas

    2015-01-01

    Gas hydrate formation in multi phase mixtures containing an aqueous phase (with dissolved salts), reservoir fluid (crude oil) and natural gas phase was investigated by using a standard rocking cell (RC-5) apparatus. The hydrate formation temperature was reduced in the presence of crude oils...... in comparison with that in pure water. This observed hydrate inhibition potential shows significant variation depending on the type of crude oil. The influence of crude oil composition (saturates, aromatics, resins and asphaltenes) on this behavior was probably due to the existence of a combination of different...... inhibition mechanisms and potentially a competition among inhibition-promotion mechanisms. Moreover, the hydrate formation time has been determined at different water cuts in each crude oil and it was found that the inhibition capability increases with an increase in the oil content. The effect...

  5. Photodegradation of 2,4-Dichlorophenol in Aqueous Systems under Simulated and Natural Sunlight

    Directory of Open Access Journals (Sweden)

    Dorota Gryglik

    2016-01-01

    Full Text Available The work presents results of studies on 2,4-dichlorophenol (2,4-DCP degradation in aqueous solutions using photochemically initiated processes by simulated and natural sunlight. A number of possible substrate photodegradation routes were investigated, by both direct photolysis and photosensitized oxidation process. The major role of singlet oxygen in 2,4-DCP photodegradation was proved. Rose Bengal and derivatives of porphine and phthalocyanine were used as sensitizers. The influences of various process parameters on the reaction rate were investigated. On the basis of experimental data reaction rate constants of 2,4-DCP photosensitized oxidation were determined. The possibility of using natural sunlight to degrade 2,4-DCP in water in the middle latitudes was stated. The acute toxicity bioassay was conducted with the marine bacterium Vibrio fischeri as a bioluminescent indicator. The obtained results encourage further research on this process.

  6. Secondary Confinement of Water Observed in Eutectic Melting of Aqueous Salt Systems in Nanopores.

    Science.gov (United States)

    Meissner, Jens; Prause, Albert; Findenegg, Gerhard H

    2016-05-19

    Freezing and melting of aqueous solutions of alkali halides confined in the cylindrical nanopores of MCM-41 and SBA-15 silica was probed by differential scanning calorimetry (DSC). We find that the confinement-induced shift of the eutectic temperature in the pores can be significantly greater than the shift of the melting temperature of pure water. Greatest shifts of the eutectic temperature are found for salts that crystallize as oligohydrates at the eutectic point. This behavior is explained by the larger fraction of pore volume occupied by salt hydrates as compared to anhydrous salts, on the assumption that precipitated salt constitutes an additional confinement for ice/water in the pores. A model based on this secondary confinement effect gives a good representation of the experimental data. Salt-specific secondary confinement may play a role in a variety of fields, from salt-impregnated advanced adsorbents and catalysts to the thermal weathering of building materials. PMID:27124392

  7. Synthesis and study of a fluorous and photoreductible copper(II) complex with surfactant properties : application to click chemistry in biphasic perfluorocarbon-water and hydrocarbon-water systems

    OpenAIRE

    Jochyms, Quentin

    2015-01-01

    The aim of this thesis was to develop a new metallosurfactant for the catalysis between an alkyne and an azide. The goal of such a system was to keep separated the reactants and the catalyst in two different phases to facilitate the purification of the reaction mixture. The first step was to synthetized the complex [Cu(TF6)(3-benzoylbenzoate)2]. Then it was shown that this complex, insoluble in water and DIPE-water. This complex is also photoreductible to form a copper(I) complex. Finally, it...

  8. Biphasic synovial sarcoma in the cervical spine: Case report

    Directory of Open Access Journals (Sweden)

    Foreman Stephen M

    2011-05-01

    Full Text Available Abstract Synovial sarcoma is a rare malignant neoplasm of soft tissue that typically arising near large joints of the upper and lower extremities in young adult males. Only 3% of these neoplasms have been found to arise in the head and neck region. To our knowledge, there are limited reports in the literature of this neoplasm in the cervical spine. A case of biphasic synovial sarcoma of the cervical spine is reviewed. A 29 year-old male presented with pain on the left side of the cervical spine. Physical examination revealed a global loss of cervical motion and large, palpable mass in the left paravertebral area. The long-delayed Magnetic Resonance (MR scan revealed a soft tissue mass measuring 8.3 centimeters (cm × 5.7 cm that was surgically removed. A malignant biphasic synovial sarcoma was diagnosed on pathologic examination. The clinical and imaging findings of an atypically located synovial sarcoma are reviewed. This case report emphasizes the consequences of a limited differential diagnosis, prolonged treatment and the failure to perform timely diagnostic imaging in the presence of a paraspinal mass.

  9. Biphasic cardiovascular and respiratory effects induced by β-citronellol.

    Science.gov (United States)

    Ribeiro-Filho, Helder Veras; de Souza Silva, Camila Meirelles; de Siqueira, Rodrigo JoséBezerra; Lahlou, Saad; Dos Santos, Armênio Aguiar; Magalhães, Pedro Jorge Caldas

    2016-03-15

    β-Citronellol is a monoterpene found in the essential oil of various plants with antihypertensive properties. In fact, β-citronellol possesses hypotensive actions due to its vasodilator abilities. Here we aimed to show that β-citronellol recruits airway sensory neural circuitry to evoke cardiorespiratory effects. In anesthetized rats, intravenous injection of β-citronellol caused biphasic hypotension, bradycardia and apnea. Bilateral vagotomy, perivagal capsaicin treatment or injection into the left ventricle abolished first rapid phase (named P1) but not delayed phase P2 of the β-citronellol effects. P1 persisted after pretreatment with capsazepine, ondansetron, HC-030031 or suramin. Suramin abolished P2 of apnea. In awake rats, β-citronellol induced biphasic hypotension and bradycardia being P1 abolished by methylatropine. In vitro, β-citronellol inhibited spontaneous or electrically-evoked contractions of rat isolated right or left atrium, respectively, and fully relaxed sustained contractions of phenylephrine in mesenteric artery rings. In conclusion, chemosensitive pulmonary vagal afferent fibers appear to mediate the cardiovascular and respiratory effects of β-citronellol. The transduction mechanism in P1 seems not to involve the activation of transient receptor potential vanilloid subtype 1 (TRPV1), transient receptor potential ankyrin subtype 1 (TRPA1), purinergic (P2X) or 5-HT3 receptors located on airways sensory nerves. P2 of hypotension and bradycardia seems resulting from a cardioinhibitory and vasodilatory effect of β-citronellol and the apnea from a purinergic signaling. PMID:26872991

  10. Cell-material interactions on biphasic polyurethane matrix.

    Science.gov (United States)

    Dicesare, Patrick; Fox, Wade M; Hill, Michael J; Krishnan, G Rajesh; Yang, Shuying; Sarkar, Debanjan

    2013-08-01

    Cell-matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell-matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

  11. Aqueous salt blanket tritium systems for the TITAN-II reversed-field pinch fusion reactor design

    International Nuclear Information System (INIS)

    TITAN is a high-power-density reversed-field pinch reactor design. The TITAN-II concept is based on an aqueous lithium salt blanket immersed in a loop-in-pool design to provide a high level of passive safety. The blanket uses 50 Ci/kg water in the primary heat transport circuit, and 0.4 Ci/kg in the cold water pool. The main coolant stream is treated by a 5-stage Vapor Phase Catalytic Exchange process, followed by Cryogenic Distillation. Water Distillation is used to process the cold pool. The design uses proven technologies (although on a ten times larger scale), and takes advantage of features of light water tritium recovery. Tritium losses are controlled to 50 Ci/d by leak-tight design, tritium release trapping by the cold pool, lower pressure in the primary system relative to the steam system, and air driers

  12. Investigation on the extraction of strontium ions from aqueous phase using crown ether-ionic liquid systems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The extraction of strontium ions using DCH18C6 as the extractant and various ionic liquids(ILs) as solvents has been investigated.The distribution ratio of Sr2+ can reach as high as 103 under certain conditions,much larger than that in DCH18C6/n-octanol system.The extraction capacity depends greatly on the structure of ionic liquids.In Ils-based extraction systems,the extraction efficiency of strontium ions is reduced by increasing the concentration of nitric acid and can also be influenced directly by the presence of Na+ and K+ in the aqueous phase.It is confirmed that the extraction proceeds mainly via a cation-exchange mechanism.

  13. Calculation of the molecular exchanging energy of binary surfactants system on the surface monolayer of aqueous solution

    Institute of Scientific and Technical Information of China (English)

    WANG ZhengWu; YI XiZhang

    2007-01-01

    By using the binary anionic/cationic surfactants system CH3(CH2)nOSO-3/CH3(CH2)nN+(CH3)3 as an example, the molecular exchanging energy (ε) of adsorption on the surface monolayer of aqueous solution has been studied. εcan be obtained with two methods. One is from the relationship between εand the molecule interaction parameter (β). This relationship is founded by considering that the adsorption of mixed surfactants on the surface monolayer of solution satisfies the dimensional crystal model condition under which β can be obtained by testing the surface tension of solution. The other is directly from the molecular structure of surfactants with the Lennard-Jones formula. The results for the studied system show that these two methods coincide well.

  14. Calculation of the molecular exchanging energy of binary surfactants system on the surface monolayer of aqueous solution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    By using the binary anionic/cationic surfactants system CH3(CH2)nOSO3/CH3(CH2)nN+(CH3)3 as an ex-ample, the molecular exchanging energy (ε) of adsorption on the surface monolayer of aqueous solu-tion has been studied. ε can be obtained with two methods. One is from the relationship between ε and the molecule interaction parameter (β). This relationship is founded by considering that the adsorption of mixed surfactants on the surface monolayer of solution satisfies the dimensional crystal model condition under which β can be obtained by testing the surface tension of solution. The other is directly from the molecular structure of surfactants with the Lennard-Jones formula. The results for the studied system show that these two methods coincide well.

  15. Radiation-Induced Grafting for the Synthesis of Adsorbents for Phosphate and Chromate Removal from Aqueous Systems

    International Nuclear Information System (INIS)

    Nonwoven fabrics made of PE coated PP fibres were irradiated by accelerated electrons in inert atmospheres for grafting of two different monomers, glycidyl methacrylate and dimethylaminoethyl methacrylate. Grafting conditions were optimized by a systematic investigation of the effects of absorbed dose, monomer concentration, grafting reaction temperature and duration. 150% grafted copolymers were later modified by protonation and quaternization of poly(dimethylaminoethyl methacrylate) chains and by Cu(II) loading of dipyridyl amine modified poly(glycidyl methacrylate) graft chains. The PE/PP based adsorbents thus prepared were used for their suitability of removing phosphate and chromate ions from aqueous systems. Adsorption/removal studies were carried out in both batch and continuous flow type systems. The selectivity of adsorption of phosphate ions in the presence of other competing anions were also checked showing the enhanced selectivity for phosphate ions. (author)

  16. Direct extraction of genomic DNA from maize with aqueous ionic liquid buffer systems for applications in genetically modified organisms analysis.

    Science.gov (United States)

    Gonzalez García, Eric; Ressmann, Anna K; Gaertner, Peter; Zirbs, Ronald; Mach, Robert L; Krska, Rudolf; Bica, Katharina; Brunner, Kurt

    2014-12-01

    To date, the extraction of genomic DNA is considered a bottleneck in the process of genetically modified organisms (GMOs) detection. Conventional DNA isolation methods are associated with long extraction times and multiple pipetting and centrifugation steps, which makes the entire procedure not only tedious and complicated but also prone to sample cross-contamination. In recent times, ionic liquids have emerged as innovative solvents for biomass processing, due to their outstanding properties for dissolution of biomass and biopolymers. In this study, a novel, easily applicable, and time-efficient method for the direct extraction of genomic DNA from biomass based on aqueous-ionic liquid solutions was developed. The straightforward protocol relies on extraction of maize in a 10 % solution of ionic liquids in aqueous phosphate buffer for 5 min at room temperature, followed by a denaturation step at 95 °C for 10 min and a simple filtration to remove residual biopolymers. A set of 22 ionic liquids was tested in a buffer system and 1-ethyl-3-methylimidazolium dimethylphosphate, as well as the environmentally benign choline formate, were identified as ideal candidates. With this strategy, the quality of the genomic DNA extracted was significantly improved and the extraction protocol was notably simplified compared with a well-established method. PMID:25381609

  17. Purification of Active Myrosinase from Plants by Aqueous Two-Phase Counter-Current Chromatography

    Science.gov (United States)

    Wade, Kristina L.; Ito, Yoichiro; Ramarathnam, Aarthi; Holtzclaw, W. David; Fahey, Jed W.

    2014-01-01

    Introduction Myrosinase (thioglucoside glucohydrolase; E.C. 3.2.1.147), is a plant enzyme of increasing interest and importance to the biomedical community. Myrosinase catalyses the formation of isothiocyanates such as sulforaphane (frombroccoli) and 4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate (from moringa), which are potent inducers of the cytoprotective phase-2 response in humans, by hydrolysis of their abundant glucosinolate (β-thioglucoside N-hydroxysulphate) precursors. Objective To develop an aqueous two-phase counter-current chromatography (CCC) system for the rapid, three-step purification of catalytically active myrosinase. Methods A high-concentration potassium phosphate and polyethylene glycol biphasic aqueous two-phase system (ATPS) is used with a newly developed CCC configuration that utilises spiral-wound, flat-twisted tubing (with an ovoid cross-section). Results Making the initial crude plant extract directly in the ATPS and injecting only the lower phase permitted highly selective partitioning of the myrosinase complex before a short chromatography on a spiral disk CCC. Optimum phase retention and separation of myrosinase from other plant proteins afforded a 60-fold purification. Conclusion Catalytically active myrosinase is purified from 3-day broccoli sprouts, 7-day daikon sprouts, mustard seeds and the leaves of field-grown moringa trees, in a CCC system that is predictably scalable. PMID:25130502

  18. SOLUPLOT, Eh-pH Diagram, aO2-pH Diagram Plots for Aqueous Chemical Systems

    International Nuclear Information System (INIS)

    1 - Description of problem or function: SOLUPLOT is a program designed to calculate and plot complex potential - pH diagrams and log oxygen activity - pH diagrams for aqueous chemical systems, considering speciation of ligands, from free energy and thermodynamic activity data. These diagrams, commonly referred to as Eh-pH and aO2-pH diagrams, respectively, define areas of predominance in Eh-pH diagrams or aO2-pH space for chemical species of a chemical system at equilibrium. Over an area of predominance, one predominant species is at greater activity than the other species of the system considered. The diagram axes, pH (a measure of hydrogen ion activity) and either Eh or log aO2 (measures of the tendency toward either oxidation or reduction), are parameters commonly applied in describing the chemistry of aqueous systems. 2 - Method of solution: SOLUPLOT calculates a diagram involving the speciation of ligands in three general steps. First the speciation of a pH-dependent ligand system, if specified in the input data, is calculated. Since this system is solely pH-dependent, areas of predominance are defined by constant pH lines which divide the diagram vertically into a number of rectangular subsections. Secondly the program calculates the speciation of an Eh-pH- dependent ligand system, if so specified in the input data. This speciation may be represented by vertical, horizontal, and sloping bounds. The initial diagram is now effectively divided into a number of sub-diagrams, each representing the intersection of the area of predominance of one Eh-pH-dependent ligand species. Finally the program takes each sub-diagram separately and calculates the speciation of the main system. Within each sub-diagram the program actually calculates two speciations, one among all the species in the main system (the solid-aqueous diagram), and one among only the aqueous species (the aqueous species diagram). The main system within a sub-diagram includes main system species, all non

  19. Design of functional guanidinium ionic liquid aqueous two-phase systems for the efficient purification of protein

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been synthesized. • Functional guanidinium ionic liquid aqueous two-phase systems have been first designed for the purification of protein. • Mechanisms and performances of the process were researched. • Simple, green, safety and presents better purified ability than ordinary process. • A potential efficient platform for protein purification and related studies. - Abstract: A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been devised and synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids (ILs) were confirmed by 1H nuclear magnetic resonance (1H NMR) and 13C nuclear magnetic resonance (13C NMR) and the production yields were all above 90%. Functional guanidinium ionic liquid aqueous two-phase systems (FGIL-ATPSs) have been first designed with these functional guanidinium ILs and phosphate solution for the purification of protein. After phase separation, proteins had transferred into the IL-rich phase and the concentrations of proteins were determined by measuring the absorbance at 278 nm using an ultra violet visible (UV–vis) spectrophotometer. The advantages of FGIL-ATPSs were compared with ordinary ionic liquid aqueous two-phase systems (IL-ATPSs). The proposed FGIL-ATPS has been applied to purify lysozyme, trypsin, ovalbumin and bovine serum albumin. Single factor experiments were used to research the effects of the process, such as the amount of ionic liquid (IL), the concentration of salt solution, temperature and the amount of protein. The purification efficiency reaches to 97.05%. The secondary structure of protein during the experimental process was observed upon investigation using UV–vis spectrophotometer, Fourier-transform infrared spectroscopy (FT

  20. Design of functional guanidinium ionic liquid aqueous two-phase systems for the efficient purification of protein

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xueqin; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Zeng, Qun; Chen, Jing; Huang, Yanhua; Xu, Kaijia

    2014-03-01

    Graphical abstract: - Highlights: • A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been synthesized. • Functional guanidinium ionic liquid aqueous two-phase systems have been first designed for the purification of protein. • Mechanisms and performances of the process were researched. • Simple, green, safety and presents better purified ability than ordinary process. • A potential efficient platform for protein purification and related studies. - Abstract: A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been devised and synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids (ILs) were confirmed by {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) and 13C nuclear magnetic resonance (13C NMR) and the production yields were all above 90%. Functional guanidinium ionic liquid aqueous two-phase systems (FGIL-ATPSs) have been first designed with these functional guanidinium ILs and phosphate solution for the purification of protein. After phase separation, proteins had transferred into the IL-rich phase and the concentrations of proteins were determined by measuring the absorbance at 278 nm using an ultra violet visible (UV–vis) spectrophotometer. The advantages of FGIL-ATPSs were compared with ordinary ionic liquid aqueous two-phase systems (IL-ATPSs). The proposed FGIL-ATPS has been applied to purify lysozyme, trypsin, ovalbumin and bovine serum albumin. Single factor experiments were used to research the effects of the process, such as the amount of ionic liquid (IL), the concentration of salt solution, temperature and the amount of protein. The purification efficiency reaches to 97.05%. The secondary structure of protein during the experimental process was observed upon investigation using UV–vis spectrophotometer, Fourier-transform infrared

  1. Development of a continuous flow hydride generation laser-induced breakdown spectroscopic system: Determination of tin in aqueous environments

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Semira [Izmir Institute of Technology, Faculty of Science, Chemistry Department, 35430 Izmir (Turkey); Yalcin, Serife, E-mail: serifeyalcin@iyte.edu.t [Izmir Institute of Technology, Faculty of Science, Chemistry Department, 35430 Izmir (Turkey)

    2010-08-15

    The design, construction and optimization studies of a continuous flow hydride generation laser-induced breakdown spectroscopic system, HG-LIBS, for the determination of tin in aqueous environments is presented. Optimization of the Laser Induced Breakdown Spectroscopy (LIBS) signal with respect to carrier gas flow rate, analyte, acid (HCl) and reductant (NaBH{sub 4}) concentrations and flow rates was performed by using spectral emission intensity from the neutral Sn(I) line at 284.0 nm under atmospheric pressures. With flow rates of 5.0 mL/min for NaBH{sub 4} and 2.5 mL/min for HCl, optimum NaBH{sub 4} and HCl concentrations were determined as 2.0% (w/v) and 1.0% (v/v), respectively. The hydride generation efficiency of the system was tested for tin hydride, stannane (SnH{sub 4}), by inductively coupled plasma mass spectrometer (ICP-MS). It was found that higher than 99% of the analyte was released into the gaseous phase. Upon optimization, the minimum detectable Sn concentration was found as 0.3 mg/L in water samples. That corresponds to more than two orders of increase in sensitivity compared to methods that employ common sample introduction techniques in liquids analysis by LIBS. Over 90% recoveries were obtained from spiking experiments with river, tap and drinking water samples. Results illustrate potential use of the continuous flow HG-LIBS system for monitoring of Sn concentrations in aqueous environments.

  2. Bullous variant of familial biphasic lichen amyloidosis: A unique combination of three rare presentations

    Directory of Open Access Journals (Sweden)

    Vijayalaxmi Veerabasappa Suranagi

    2015-01-01

    Full Text Available A 55-year-old man presented with multiple, itchy papules and macules on the trunk and extremities. Histopathologic examination of biopsy specimens taken from three different lesions showed a subepidermal blister with amyloid deposits in the dermal papillae. No systemic disease or involvement of other organs was detected. The clinical and histological findings were compatible with a bullous variant of lichen amyloidosis (LA. Primary cutaneous localized amyloidosis usually presents with papular, macular or nodular lesions. Bullous lesions associated with LA are very rare. Furthermore, patient had seven other members in the family with similar lesions, which is also a rare occurrence. We report a case with a rare combination of biphasic, bullous variant of familial LA.

  3. Cadmium Removal from Aqueous Systems Using Opuntia albicarpa L. Scheinvar as Biosorbent

    Directory of Open Access Journals (Sweden)

    Rosa Icela Beltrán-Hernández

    2015-01-01

    Full Text Available The aim of this research was to investigate the use of a natural adsorbent like nopal (Opuntia albicarpa L. Scheinvar for removing cadmium from aqueous solutions with low concentrations of this metal. Two treatments were applied to the cladodes: a dehydration to get dehydrated nopal (DHN and heating up to 90°C to obtain a thermally treated nopal (TN. After examining the effect of various pH values (2–7, the capacity of each biosorbent was examined in batch sorption tests at different dosages (0, 500, 1000, 1500, 2000, and 3000 mg L−1. The results indicated that adsorption of cadmium to biomass of DHN and TN was highly dependent on pH and biosorbent dosage. The best removal of cadmium (53.3%, corresponding to qe of 0.155 mg g−1 was obtained at pH 4.0 by using the TN sorbent. Infrared and Raman spectra confirmed that cadmium removal occurred via adsorption to –OH functional groups.

  4. Cadmium Removal from Aqueous Systems Using Opuntia albicarpa L. Scheinvar as Biosorbent

    Science.gov (United States)

    Beltrán-Hernández, Rosa Icela; Juárez-Santillán, Luis Felipe; Martínez-Ugalde, Ivan; Coronel-Olivares, Claudia; Lucho-Constantino, Carlos Alexander

    2015-01-01

    The aim of this research was to investigate the use of a natural adsorbent like nopal (Opuntia albicarpa L. Scheinvar) for removing cadmium from aqueous solutions with low concentrations of this metal. Two treatments were applied to the cladodes: a dehydration to get dehydrated nopal (DHN) and heating up to 90°C to obtain a thermally treated nopal (TN). After examining the effect of various pH values (2–7), the capacity of each biosorbent was examined in batch sorption tests at different dosages (0, 500, 1000, 1500, 2000, and 3000 mg L−1). The results indicated that adsorption of cadmium to biomass of DHN and TN was highly dependent on pH and biosorbent dosage. The best removal of cadmium (53.3%, corresponding to qe of 0.155 mg g−1) was obtained at pH 4.0 by using the TN sorbent. Infrared and Raman spectra confirmed that cadmium removal occurred via adsorption to –OH functional groups. PMID:26783531

  5. Radiation formation of Al-Ni bimetallic nanoparticles in aqueous system

    International Nuclear Information System (INIS)

    This work concerns the study of Al-Ni bimetallic nanoparticles synthesized by gamma-radiolysis of aqueous solution containing aluminium chloride hexahydrate, nickel chloride hexahydrate, polyvinyl alcohol for capping colloidal nanoparticles, and isopropanol as radical scavenger. While the Al/Ni molar ratio is kept constant, size of the nanoparticles can be well controlled by varying the radiation dose. The products were characterized by UV-vis spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD). Observations of UV-vis absorption spectra and TEM images showed that as the radiation dose increases from 50 to 100 kGy the particle size decreases and the number particles distribution increases. It may be explained due to the competition between nucleation and aggregation processes in the formation of metallic nanoparticles under irradiation. The EDX and XRD analysis confirmed directly the formation of Al-Ni bimetallic nanoparticles in form of alloy nanoparticles. (author)

  6. Cadmium Removal from Aqueous Systems Using Opuntia albicarpa L. Scheinvar as Biosorbent.

    Science.gov (United States)

    Beltrán-Hernández, Rosa Icela; Vázquez-Rodríguez, Gabriela Alejandra; Juárez-Santillán, Luis Felipe; Martínez-Ugalde, Ivan; Coronel-Olivares, Claudia; Lucho-Constantino, Carlos Alexander

    2015-01-01

    The aim of this research was to investigate the use of a natural adsorbent like nopal (Opuntia albicarpa L. Scheinvar) for removing cadmium from aqueous solutions with low concentrations of this metal. Two treatments were applied to the cladodes: a dehydration to get dehydrated nopal (DHN) and heating up to 90°C to obtain a thermally treated nopal (TN). After examining the effect of various pH values (2-7), the capacity of each biosorbent was examined in batch sorption tests at different dosages (0, 500, 1000, 1500, 2000, and 3000 mg L(-1)). The results indicated that adsorption of cadmium to biomass of DHN and TN was highly dependent on pH and biosorbent dosage. The best removal of cadmium (53.3%, corresponding to q e of 0.155 mg g(-1)) was obtained at pH 4.0 by using the TN sorbent. Infrared and Raman spectra confirmed that cadmium removal occurred via adsorption to -OH functional groups. PMID:26783531

  7. Smoothed particle hydrodynamics: Applications to migration of radionuclides in confined aqueous systems

    Science.gov (United States)

    Mayoral-Villa, Estela; Alvarado-Rodríguez, Carlos E.; Klapp, Jaime; Gómez-Gesteira, Moncho; Di G. Sigalotti, Leonardo

    2016-04-01

    A smoothed particle hydrodynamics (SPH) model is presented for simulating the decay chain transport of radionuclides in confined aqueous solutions. The SPH formulation is based on the open-source parallel code DualSPHysics extended to solve the advective-diffusion equation for the evolution of the concentration field coupled to the fluid-dynamic equations, including the effects of radioactive decay of the tracer contaminants. The performance of the method is demonstrated for environmental engineering problems dealing with the transport of contaminants in still and flowing water. The results from a series of benchmark test calculations are described in two- and three-space dimensions, where the advection, diffusion, and radioactive decay modes are tested separately and in combined form. The accuracy of the present SPH transport model is shown by direct comparison with the analytical solutions and results from other SPH approaches. For a given problem, convergence of the SPH solution is seen to increase with decreasing particle size and spacing.

  8. Melanoidin Removal Mechanism in An Aqueous Adsorption System: An Equilibrium, Kinetic and Thermodynamic Study.

    Science.gov (United States)

    Nunes, Diego L; Oliveira, Leandro S; Franca, Adriana S

    2015-01-01

    Melanoidins are colored products that can be found in food and drinks, formed by Maillard reactions. Sometimes these compounds are considered undesirable in certain food products, because they impart a brownish color and must be removed. An overview of recent patents related to melanoidin removal indicates that it can be performed by chemical/biological degradation or by adsorption processes. Therefore, in the present study, the adsorption mechanism for synthetic melanoidin removal from aqueous solutions was studied using different Raphanus sativus press-cake sorbents, with the precursor material being carbonized in a microwave oven, either with direct heating or after a chemical activation process with phosphoric acid, nitric acid or potassium hydroxide. Physical and chemical modifications were evaluated by FTIR, pHPZC, thermogravimetry and BET. The adsorption kinetics was better described by a pseudo-second order model for all activated carbons (ACs). Evaluation of the diffusion process showed dependence on the initial melanoidin concentration due to the wide range of sizes of the adsorbed molecules. The equilibrium data were best fitted by the Langmuir model for the acid-treated AC and by the Freundlich model for the base-treated and non-chemically treated ACs. Melanoidin adsorption was characterized as a spontaneous, favorable and endothermic process involving hydrogen bonds and π-π interactions between the adsorbents surfaces and the adsorbed molecules. PMID:26013772

  9. Radiation Chemistry of Aqueous Solutions Related to Nuclear Reactor Systems and Spent Fuel Management

    International Nuclear Information System (INIS)

    In this thesis the rate constants for a number of radical reactions in aqueous solution have been studied in a wide temperature range. The reactions of H with H2O2, OH and HO2 and the reactions of HO2 with OH, Fe2+ and Cu2+ have been studied. For each reaction rate constants have been determined as a function of temperature using the technique of high temperature, high pressure (HTP) pulse radiolysis. The rate constants were obtained by fitting a kinetic computer model to the experimental data. From an Arrhenius plot the activation energy of each reaction was determined. The data determined in this way are important for modeling of radiolysis in nuclear light water reactors. A previously developed model for calculation of the effect of water radiolysis products on oxidation and dissolution of spent nuclear fuel has been improved. In the new model, called TraRaMo, simultaneous transport by diffusion and chemical reactions induced by radiolysis can be modeled. The model is a compartment model. After a radiolysis calculation in each compartment, diffusion of the species are allowed to take place before a new radiolysis calculation in the next time step. Three different types of radiation can be simulated simultaneously

  10. Study of the dose response of the system ferrous ammonium sulfate–sucrose–xylenol orange in acid aqueous solution

    International Nuclear Information System (INIS)

    An aqueous solution of ammonium ferrous sulfate–sucrose–xylenol orange in sulfuric acid (FSX) is proposed as a dosimetric system for the processes of gamma irradiation in a range between 0.3 and 6 Gy. This system is based on the indirect oxidation of ferrous ion by an organic compound (sucrose) to ferric ion and on the formation of a color complex of Fe3+ in an acidic medium with xylenol orange (a dye). After gamma radiation, an observable change occurs in the color of the system. Irradiation was executed at three different temperatures (13 °C, 22 °C, and 40 °C). A spectrometric readout method at 585 nm was employed to evaluate the system's dose response. In all of the cases analyzed, the responses had a linear behavior, and a slight effect of irradiation temperature was observed. Post-irradiation response was also evaluated and showed the stability of the solutions 24 h after the irradiation. The results obtained suggest that FSX might be used as a dosimeter for low doses of gamma irradiation because it provides a stable signal, good reproducibility, and an accessible technique for analysis. - Highlights: • The system ferrous-sucrose-xylenol is reproducibility with less than 5% error. • The dosimeter has low cost and easy readout using UV-vis spectrometry, and the response is stable for several days. • The system proposed is suitable for low irradiation doses

  11. Metal-free aqueous redox capacitor via proton rocking-chair system in an organic-based couple.

    Science.gov (United States)

    Tomai, Takaaki; Mitani, Satoshi; Komatsu, Daiki; Kawaguchi, Yuji; Honma, Itaru

    2014-01-01

    Safe and inexpensive energy storage devices with long cycle lifetimes and high power and energy densities are mandatory for the development of electrical power grids that connect with renewable energy sources. In this study, we demonstrated metal-free aqueous redox capacitors using couples comprising low-molecular-weight organic compounds. In addition to the electric double layer formation, proton insertion/extraction reactions between a couple consisting of inexpensive quinones/hydroquinones contributed to the energy storage. This energy storage mechanism, in which protons are shuttled back and forth between two electrodes upon charge and discharge, can be regarded as a proton rocking-chair system. The fabricated capacitor showed a large capacity (>20 Wh/kg), even in the applied potential range between 0-1 V, and high power capability (>5 A/g). The support of the organic compounds in nanoporous carbon facilitated the efficient use of the organic compounds with a lifetime of thousands of cycles. PMID:24395117

  12. Differential partition of virulent Aeromonas salmonicida and attenuated derivatives possessing specific cell surface alterations in polymer aqueous-phase systems

    Science.gov (United States)

    Van Alstine, J. M.; Trust, T. J.; Brooks, D. E.

    1986-01-01

    Two-polymer aqueous-phase systems in which partitioning of biological matter between the phases occurs according to surface properties such as hydrophobicity, charge, and lipid composition are used to compare the surface properties of strains of the fish pathogen Aeromonas salmonicida. The differential ability of strains to produce a surface protein array crucial to their virulence, the A layer, and to produce smooth lipopolysaccharide is found to be important in the partitioning behavior of Aeromonas salmonicida. The presence of the A layer is shown to decrease the surface hydrophilicity of the pathogen, and to increase specifically its surface affinity for fatty acid esters of polyethylene glycol. The method has application to the analysis of surface properties crucial to bacterial virulence, and to the selection of strains and mutants with specific surface characteristics.

  13. Distribution and speciation of cesium, strontium, and europium in the aqueous two-phase system milk-pectin

    International Nuclear Information System (INIS)

    Partition of radionuclides in aqueous liquid-liquid systems allows speciation of bioinorganic forms under nondenaturing conditions. From the fresh pasteurized skim bovine milk spiked with respective radionuclides and agitated with 4% w/w water solution of apple pectin, about 80% of cesium, 22% of strontium and less than 1.5% of europium is recovered with the pectin, phase at an initial milk - pectin volume ratio of 7:3. This recovery fraction is proportional to the abundance of radionuclides in milk serum. No protein bound fraction of strontium extractable by Aerosol OT in isooctane was obtained. More than 3-fold preconcentration of strontium and europium radionuclides in milk is achieved after 10-15 min membraneless osmosis with pectin phase. (author) 26 refs.; 6 tabs

  14. Development of a fluidized bed system for adsorption of phenol from aqueous solutions with commercial macroporous resins

    Directory of Open Access Journals (Sweden)

    R. A. Corrêa

    2007-03-01

    Full Text Available This work is related to removal of phenol from wastewaters by adsorption onto polymeric resins, a current alternative to activated carbon. A closed circuit, bench-scale liquid fluidized bed system was developed for this purpose. Phenol aqueous solutions with initial concentrations in the range of 0.084 to 0.451 kg/m³ were used to fluidize small permeable capsules of stainless steel screen containing a commercial resin at 308 K. Experiments were carried out using a fluidizing velocity 20% above that of the minimum fluidization of the capsules. Typically, 30 passages of the liquid volume circulating through the bed were required to reach a quasi-equilibrium concentration of phenol in the treated effluent. A simple batch adsorption model using the Freundlich isotherm successfully predicted final phenol concentrations. Suspended solids, often present in residual waters and a common cause of fixed bed clogging, were simulated with wood sawdust.

  15. Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol/Sodium Polyacrylate/Salts

    Directory of Open Access Journals (Sweden)

    Adalberto Pessoa Junior

    2011-03-01

    Full Text Available Aqueous two-phase systems consisting of polyethylene glycol (PEG, sodium polyacrylate (NaPAA, and a salt have been studied. The effects of the polymer size, salt type (NaCl, Na2SO4, sodium adipate and sodium azelate and salt concentrations on the position of the binodal curve were investigated. The investigated PEG molecules had a molar mass of 2,000 to 8,000 g/mol, while that of NaPAA was 8,000 g/mol. Experimental phase diagrams, and tie lines and calculated phase diagrams, based on Flory-Huggins theory of polymer solutions are presented. Due to strong enthalpic and entropic balancing forces, the hydrophobicity of the added salt has a strong influence on the position of the binodal, which could be reproduced by model calculations.

  16. Comb polymer architecture and particle size effects on the behavior of biphasic nanoparticle inks for direct-write assembly

    Science.gov (United States)

    Yoshikawa, Jun

    Biphasic nanoparticle mixtures composed of attractive and repulsive colloidal species enable the direct-write assembly of 3D structures with much finer features than those produced by pure colloidal gels. These mixtures rely on the use of comb polymer dispersants to render one particle population stable, while the other population is attractive. In this thesis, we systematically investigate the effects of comb polymer architecture and particle size ratio on the behavior of biphasic nanoparticle inks with the overarching aim of further advancing the direct-write assembly of 3D colloidal structures. We first investigated the effects of both pure polyelectrolytes, poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA), and comb polymer dispersants composed of a PMAA backbone with methoxy-poly(ethylene oxide) (mPEO) teeth of varying molecular weights on the stability of barium titanate (BaTiO 3) suspensions. While each dispersant imparts stability to BaTiO 3 nanoparticles at low ionic strength (nanoparticle suspensions are studied. Shear elastic modulus, shear yield stress, and compressive yield stress are measured for mixtures of varying total volume fraction, attractive-to-repulsive volume fraction, and particle size ratio between attractive and repulsive species. Our observations indicate that the repulsive particles hinder the formation of the attractive gel network. The time required for shear elastic modulus to approach a steady-state value increases with the fraction of repulsive species. Furthermore, this behavior becomes more significant with increasing the repulsive particle size. Additionally, we find that biphasic suspensions composed of both identical and different mean particle sizes exhibit larger φ-scaling exponents for compressive yield stress than shear yield stress, indicating that such systems become more resistant to compression with increasing φ. This observation suggests that the biphasic suspensions flowing through fine nozzles are more

  17. Extraction of penicillin G by aqueous two-phase system of [Bmim]BF4/NaH2PO4

    Institute of Scientific and Technical Information of China (English)

    LIU Qingfen; HU Xuesheng; WANG Yuhong; YANG Ping; XIA Hansong; YU Jiang; LIU Huizhou

    2005-01-01

    A novel approach for the extraction of penicillin G by aqueous two-phase system comprised of hydrophilic ionic liquid [Bmim]BF4 (1-butyl-3- methylimidazolium tetrafluoroborate) and NaH2PO4 is reported. The effects of some important parameters involving the concentration of NaH2PO4, the concentration of penicillin G, the amount of [Bmim]BF4 on the formation of aqueous two-phase system and the extraction yield of penicillin were investigated. The primary result shows that the ATPS can take advantage of penicillin concentrated in upper phase at higher pH value for penicillin extraction from its aqueous solution without emulsification.

  18. Effects of the Optimised pH and Molar Ratio on Struvite Precipitation in Aqueous System

    Directory of Open Access Journals (Sweden)

    Edahwati Luluk

    2016-01-01

    Full Text Available Struvite (MgNH4PO4.6H2O is one of phosphate minerals, commonly forms into aqueous solutions. It can be precipitated as mineral deposits for optimization of phosphate recovery based on the pH optimum, molar ratio and temperature levels. This paper presents results of a study on the struvite precipitation under the influence of pH variation, at optimized molar ratio and temperature, which were calculated from an experimental design methodology. Based on the methodology, a laboratory prepared struvite, made by mixing solutions to NH4OH, MgCl2 and H3PO4 for a molar ratio of 1: 2: 1 in a 500 mL volume of batch stirred crystallizer at room temperature. The crystallization was done at 200 rpm and the pH variation was adjusted to 8, 9 and 10 with KOH for a time of 70 minutes. The resulting crystals were filtered and dried at room temperature for 48 h and subsequently stored for further analysis. Material characterisasion of the crystals was conducted using XRPD Rietveld method of mineralogical composition. SEM equipped by EDX was employed for investigation of morphology and elemental composition of the crystals obtained. During the experiment, struvite crystals were firstly nucleated and subsequently developed at major value. The increase in pH is assumed to convert some of the struvite phase into struvite (K and minor sylvite (KCl. It demonstrates that Visual MINTEQ can be employed to estimate the mineral formation out the synthetic solutions.

  19. Effects of Water Hardness on Textile Detergency Performance in Aqueous Cleaning Systems.

    Science.gov (United States)

    Gotoh, Keiko; Horibe, Kaori; Mei, Yang; Tsujisaka, Toshiyuki

    2016-01-01

    The effects of water hardness on textile detergency in aqueous solutions were systematically investigated using four surfactants: sodium oleate (OLNa), linear dodecylbenzene sulfonate (LAS), sodium dodecyl sulfate (AS), and polyoxyethylene (10) dodecyl ether (AE). Water hardness was adjusted according to the standard procedure described in IEC 60734:2012. As expected, by adding hardness salts the surface tension of the OLNa solution increased. Surprisingly, the addition of hardness salts lowers the surface tension for the LAS and AS solutions. In the case of the AE solution, hardness salt did not affect the surface tension. A decrease in transmittance and foamability after adding hardness salts was observed for every anionic surfactant solution, indicating that anionic surfactants can combine with divalent ions to form insoluble precipitates. Detergency experiments were performed using cotton plain-woven and towel fabrics soiled with a carbon black and oleic acid mixture. One piece each of untreated and soiled fabric were stacked and placed horizontally in detergent solution with or without hardness salts. As a mechanical action of soil removal, the shaking of 190 spm was applied. Soil removal and redeposition due to washing were evaluated from changes in values of the Kubelka-Munk function for both fabrics. With increasing water hardness, soil removal decreased and redeposition increased. In order of decreasing detergency, the surfactants were as follows: LAS > OLNa ≈ AS > AE. The results indicate that precipitates, formed by reaction of LAS or AS with hardness salts, are strongly adsorbed on the water surface because of their hydrophobicity, but they have no detergency power. The field emission scanning electron microscopic observation and X-ray photoelectron spectroscopic analysis showed that Ca(LAS)2 precipitation clung to fiber surfaces, and remained on the surfaces after washing. Significant changes in the cotton fabric due to washing were observed in

  20. Biomonitoring and assessment of monomethylmercury exposure in aqueous systems using the DGT technique

    Energy Technology Data Exchange (ETDEWEB)

    Clarisse, O., E-mail: olivier.clarisse@umoncton.ca [Trent University, Chemistry Department, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada); Universite de Moncton, Departement de Chimie et de Biochimie, Moncton, New Brunswick E1A 3E9 (Canada); Lotufo, G.R. [Environmental Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS 39180-6199 (United States); Hintelmann, H. [Trent University, Chemistry Department, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada); Best, E.P.H. [Environmental Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS 39180-6199 (United States); U.S. Environmental Protection Agency, National Risk Management Research Laboratory, 26 West Martin Luther King Boulevard, Cincinnati, OH 45268 (United States)

    2012-02-01

    A series of laboratory experiments was conducted under realistic environmental conditions to test the ability of the Diffusive Gradient in Thin film (DGT) technique to mimic monomethylmercury (MMHg) bioaccumulation by a clam (Macoma balthica, Baltic clam). Using isotope enriched MMHg as tracers, bioavailability was determined by comparing the rate of MMHg uptake by novel DGT devices and sentinel organism over time. Experiments were conducted under varying conditions of salinity and MMHg speciation. Depending on MMHg level and speciation in the dissolved phase, MMHg uptake rates by the sentinel organism varied greatly from 0.4 to 2.4 L g{sup -1} d{sup -1}. Reproducibilities of MMHg uptakes by DGT and clams were estimated at 7 and 38%, respectively. A significant linear relationship (log basis) between MMHg accumulation by DGT and clams was observed (r{sup 2} = 0.89). The study demonstrates that DGT results reasonably predict MMHg uptake by clams from the aqueous phase and provide the basis for application of the DGT device as a surrogate for sentinel organism for monitoring bioavailable MMHg. - Highlights: Black-Right-Pointing-Pointer We investigate the potential of DGT devices to act as surrogates for sentinel organism. Black-Right-Pointing-Pointer We compare monomethylmercury accumulation in DGT devices and in clams from the dissolved phase. Black-Right-Pointing-Pointer We examine the effects of salinity and MMHg speciation on MMHg accumulation by DGT and clams. Black-Right-Pointing-Pointer For all laboratory experiments, a strong overall correlation between MMHg accumulations in clams and DGTs is observed.

  1. Biphasic 201thallium scintgraphy after dipyridamole in mitral valve diseases

    International Nuclear Information System (INIS)

    The results of biphasic 201thallium scintigraphy after dipyridamole i.v. could neither prove nor exclude the presence of small focal lesions in the myocardium of 17 patients with mitral valve diseases. The frequent finding of a decrease in activity in the anterolateral myocardium is probably due to a relative increase in activity in the region of the inferior wall with superimposed areas of the papillary muscle and right ventricular myocardium. If the right ventricle is visualized in stress- or redistribution images, an increase in mean pulmonary artery pressure can be accepted. According to Cohen's criteria, a grade 2 or 3 virtually proves the existence of pulmonary hypertension, a grade 1 makes this finding rather probable. The possibility of pulmonary hypertension can not be excluded if the right ventricular myocardium is not visualized. (orig.)

  2. Bioplastique: a new biphasic polymer for minimally invasive injection implantation.

    Science.gov (United States)

    Ersek, R A; Beisang, A A

    1992-01-01

    The search for prosthetic materials that are biocompatible, nontoxic, and permanent led the authors to develop a micronized, inert, biphasic polymer particle for permanent soft tissue augmentation which neither migrates nor is absorbed by the body. Placed in a bioexcretable gel carrier, these textured microparticles are easily implanted using a specially designed blunt-tipped cannula with local anesthesia on an outpatient basis. Research using this implant material, Bioplastique (Bioplasty, St. Paul, MN), in rabbits has shown that when the textured particle size is maintained within a critical range, neither particle migration nor storage disease occurs. The gel carrier is rapidly phagocytized and replaced by fibrin matrix within a few days. Host collagen then gradually forms a fibrotic capsule around each textured particle, making use of the naturally occurring foreign body reaction to create a stable inplant. After being followed for over two years, Bioplastique has proven to be useful in many clinical applications with few complications. PMID:1734632

  3. Biphasic presence of fibrocytes in a porcine hypertrophic scar model.

    Science.gov (United States)

    Travis, Taryn E; Mino, Matthew J; Moffatt, Lauren T; Mauskar, Neil A; Prindeze, Nicholas J; Ghassemi, Pejhman; Ramella-Roman, Jessica C; Jordan, Marion H; Shupp, Jeffrey W

    2015-01-01

    The duroc pig has been described as a promising animal model for use in the study of human wound healing and scar formation. However, little is known about the presence and chronology of the fibrocyte cell population in the healing process of these animals. Wounds known to form scar were created on red duroc swine (3" x 3") with a dermatome to a total depth of either 0.06 inches or 0.09 inches. These wounds were allowed to heal completely and biopsies were done at scheduled time points during the healing process. Biopsies were formalin fixed and paraffin embedded for immunohistochemical analysis. Porcine reactive antibodies to CD-45 and procollagen-1 and a human reactive antibody to LSP-1 were used to detect the presence of fibrocytes in immunohistochemistry, an immunocytochemistry. Initial immunohistochemical studies showed evidence of a biphasic presence of fibrocytes. Pigs with 0.06 inches deep wounds showed positive staining for CD-45 and LSP-1 within highly cellular areas at days 2 and 4 after wounding. Additional animals with 0.09 inches deep wounds showed positive staining within similar areas at days 56, 70, and 113 after wounding. There was no immunohistochemical evidence of fibrocytes in skin biopsies taken at days 14, 28, or 42. Procollagen-1 staining was diffused in all samples. Cultured cells were stained for CD-45, LSP-1, and procollagen-1 by immunocytochemistry. These data confirm that fibrocytes are indeed present in this porcine model. We conclude that these cells are present after initial wounding and later during scar formation and remodeling. We believe that this is an evidence of a biphasic presence of fibrocytes, first as an acute response to skin wounding followed by later involvement in the remodeling process, prompted by continued inflammation in a deep partial thickness wound. PMID:25051518

  4. Experimental determination and thermodynamic modeling of phase equilibrium and protein partitioning in aqueous two-phase systems containing biodegradable salts

    International Nuclear Information System (INIS)

    Highlights: ► Binodal data of systems (water + polyethyleneglycol + sodium) succinate are reported. ► Pitzer model describes the phase equilibrium of systems formed by polyethyleneglycol and biodegradable salts satisfactorily. ► This simple thermodynamic framework was able to predict the partitioning behaviour of model proteins acceptably well. - Abstract: Phase diagrams of sustainable aqueous two-phase systems (ATPSs) formed by polyethyleneglycols (PEGs) of different average molar masses (4000, 6000, and 8000) and sodium succinate are reported in this work. Partition coefficients (Kps) of seven model proteins: bovine serum albumin, catalase, beta-lactoglobulin, alpha-amylase, lysozyme, pepsin, urease and trypsin were experimentally determined in these systems and in ATPSs formed by the former PEGs and other biodegradable sodium salts: citrate and tartrate. An extension of Pitzer model comprising long and short-range term contributions to the excess Gibbs free energy was used to describe the (liquid + liquid) equilibrium. Comparison between experimental and calculated tie line data showed mean deviations always lower than 3%, thus indicating a good correlation. The partition coefficients were modeled by using the same thermodynamic approach. Predicted and experimental partition coefficients correlated quite successfully. Mean deviations were found to be lower than the experimental uncertainty for most of the assayed proteins.

  5. Countercurrent Chromatographic Separation of Lipophilic Ascorbic Acid Derivatives and Extract from Kadsura Coccinea Using Hydrophobic Organic-Aqueous Two-Phase Solvent Systems

    OpenAIRE

    Shinomiya, Kazufusa; Li, Heran; Kitanaka, Susumu; Ito, Yoichiro

    2009-01-01

    Countercurrent chromatographic (CCC) separation of lipophilic ascorbic acid derivatives and the crude extract from Kadsura Coccinea was performed using the type-J multilayer coil planet centrifuge with a hydrophobic organic-aqueous two-phase solvent system composed of n-hexane/ethyl acetate/ethanol/aqueous 0.1% trifluoroacetic acid at the volume ratio of (5 : 5 : 6 : 2). The lipophilic ascorbic acid derivatives were separated in the order of L-ascrobyl 2,6-dibutyrate, L-ascorbyl 6-palmitate a...

  6. The Effect of pH Difference Between Two Phases on the Partition of Lysozyme in Aqueous Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the investigation of effect of KSCN on the partitioning of lysozyme in PEG2000/ammonium sulfate aqueous two-phase system, it was found that the KSCN could alter the pH difference between the two phases, and thus affect the partition of lysozyme. The relationship between partition coefficients of lysozyme and pH differences between two phases was discussed.

  7. Enteric coating of ibuprofen tablets (200 mg using an aqueous dispersion system

    Directory of Open Access Journals (Sweden)

    Rabia Bushra

    2010-03-01

    Full Text Available Ibuprofen is a propionic acid derivative that belongs to the class NSAIDs. Major adverse reactions associated with Ibuprofen are related to GIT and include peptic and mucosal ulcers, dyspepsia, severe gastric pain and bleeding, that results in excessive treatment failure. The goal of this study was to develop enteric coated ibuprofen tablets in order to avoid gastric mucosal irritation, diffusion of drug across mucosal lining and to let active ingredient be absorbed easily in small intestine. The formulation was developed and manufactured through the direct compression process, the simplest, easiest and most economical method of manufacturing. Enteric coating was done using an Opadry white subcoating and an aqueous coating dispersion of Acryl-Eze. Enteric coated formulation was subjected to disintegration and dissolution tests by placing in 0.1 M hydrochloric acid for 2 h and then 1 h in phosphate buffer with a pH of 6.8. About 0.04% of drug was released in the acidic phase and 99.05% in the basic medium. These results reflect that ibuprofen can be successfully enteric coated in order to prevent its release in the stomach and facilitate rapid release of the drug in the duodenum, due to the presence of superdisintegrant. Formulating this enteric coated tablets could increase patient compliance by decreasing adverse drug reactions (ADR S associated with Ibuprofen therapy.Ibuprofeno é um derivado do ácido propiônico, que pertence à classe dos fármacos não-esteróides (AINES. As principais reações adversas associadas com o ibuprofeno se referem àquelas do trato gastrintestinal (TGI, como úlceras pépticas e da mucosa, dispepsia, dor gástrica grave e sangramento, que resultam em muitas falhas de tratamento. O objetivo do estudo foi desenvolver comprimidos revestidos de ibuprofeno que impeçam a irritação da mucosa gástrica, difusão do fármaco através da mucosa e permitam, facilmente, a absorção do princípio ativo do intestino

  8. Capillary electrophoresis of some free fatty acids using partially aqueous electrolyte systems and indirect UV detection. Application to the analysis of oleic and linoleic acids in peanut breeding lines

    Science.gov (United States)

    This study has shown for the first time the suitability of CE with a partially aqueous electrolyte system for the analysis of free fatty acids (FFA's) in small portions of single peanut seeds. The partially aqueous electrolyte system consisted of 40 mM Tris, 2.5 mM adenosine-5'-monophosphate (AMP) ...

  9. Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

    Directory of Open Access Journals (Sweden)

    B. D. Castro

    2005-09-01

    Full Text Available Liquid-liquid extraction using aqueous two-phase systems is a highly efficient technique for separation and purification of biomolecules due to the mild properties of both liquid phases. Reliable data on the phase behavior of these systems are essential for the design and operation of new separation processes; several authors reported phase diagrams for polymer-polymer systems, but data on polymer-salt systems are still relatively scarce. In this work, experimental liquid-liquid equilibrium data on water + polyethylene glycol 8000 + magnesium sulfate and water + polyethylene glycol 8000 + sodium sulfate aqueous two-phase systems were obtained at 35°C. Both equilibrium phases were analyzed by lyophilization and ashing. Experimental results were correlated with a mass-fraction-based NRTL activity coefficient model. New interaction parameters were estimated with the Simplex method. The mean deviations between the experimental and calculated compositions in both equilibrium phases is about 2%.

  10. Degradation of Acid Orange 7 in aqueous solution by dioxygen activation in a pyrite/H₂O/O₂ system.

    Science.gov (United States)

    Hao, Feifei; Guo, Weilin; Lin, Xin; Leng, Yanqiu; Wang, Anqi; Yue, Xinxin; Yan, Liangguo

    2014-05-01

    Increasing attention has been paid to pyrite due to its ability to generate hydroxyl radicals in air-saturated solutions. In this study, the mineral pyrite was studied as a catalyst to activate molecular oxygen to degrade Acid Orange 7 (AO7) in aqueous solution. A complete set of control experiments were conducted to optimize the reaction conditions, including the dosage of pyrite, the AO7 concentration, as well as the initial pH value. The role of reactive oxygen species (ROS) generated by pyrite in the process was elucidated by free radical quenching reactions. Furthermore, the concentrations of Fe(II) and total Fe formed were also measured. The mechanism for the production of ROS in the pyrite/H2O/O2 system was that H2O2 was formed by hydrogen ion and superoxide anion (O2(·-)) which was produced by the reaction of pyrite activating O2 and then reacted with Fe(II) dissolved from pyrite to produce (·)OH through Fenton reaction. The findings suggest that pyrite/H2O/O2 system is potentially practical in pollution treatment. Moreover, the results provide a new insight into the understanding of the mechanism for degradation of organic pollutants by pyrite. PMID:24510532

  11. Purification of C-phycocyanin from Spirulina platensis in aqueous two-phase systems using an experimental design

    Directory of Open Access Journals (Sweden)

    Francine Silva Antelo

    2015-02-01

    Full Text Available C-phycocyanin from Spirulina platensis was purified in aqueous two-phase systems (ATPS of polyethylene glycol (PEG/potassium phosphate, varying the molar mass of the PEG. Results using a full factorial design showed that an increase in the concentration of salt and decrease in the concentration of PEG caused an increment in the purification factor for all the ATPS studied. Optimization of the conditions of the purification was studied using a central composite rotatable design for each molar mass of PEG. The ATPS composed of 7% (w/w PEG 1500 or 4% (w/w PEG 8000 (g/gmol and 23 or 22.5% (w/w of phosphate resulted a purification factor of 1.6-fold for C-phycocyanin, with total and 57% recovery, respectively. Process conditions were optimized for the purification factor for the system with PEG 1500. The ATPS with 4% (w/w PEG 4000 or 4% (w/w PEG 6000 and 21% (w/w phosphate resulted purification factors of 2.1 and 2.2-fold, recovering 100% and 73.5%, respectively of C-phycocyanin in the top phase.

  12. Partitioning of L-methionine in aqueous two-phase systems containing poly(propylene glycol) and sodium phosphate salts

    Energy Technology Data Exchange (ETDEWEB)

    Salabat, Alireza, E-mail: a-salabat@araku.ac.ir [Chemistry Department, Arak University, P.O. Box 38156-879, Arak (Iran, Islamic Republic of); Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj, Kurdistan 66135 (Iran, Islamic Republic of); Moghadam, Somayeh Tiani [Chemistry Department, Arak University, P.O. Box 38156-879, Arak (Iran, Islamic Republic of); Jamehbozorg, Bahman [Department of Chemistry, University of Kurdistan, Sanandaj, Kurdistan 66135 (Iran, Islamic Republic of)

    2011-10-15

    Highlights: > Thermodynamics parameters for partitioning of L-methionine in ATPS. > Investigation of different effects on partition coefficient of the amino acid. > Propose the best condition for L-methionine partitioning. - Abstract: The partitioning behavior of L-methionine has been studied in aqueous two-phase systems of (poly(propylene glycol) + sodium phosphate salts + H{sub 2}O) at different temperatures. The salts used were sodium di-hydrogen phosphate (NaH{sub 2}PO{sub 4}), di-sodium hydrogen phosphate (Na{sub 2}HPO{sub 4}) and tri-sodium phosphate (Na{sub 3}PO{sub 4}). The effects of tie line length, salt type, and temperature on the partition coefficient of this amino acid have been studied. In addition, thermodynamic parameters ({Delta}H{sup o}, {Delta}S{sup o} and {Delta}G{sup o}) as a function of temperature were calculated. The results showed that increasing tie line length led to decreasing of the partition coefficient. We also showed that the partition coefficients of the amino acid in the systems containing Na{sub 3}PO{sub 4} are greater than the other two salts. Moreover, it is verified that increasing temperature led to decreasing the partition coefficient. The experimental partition coefficient data are correlated using a modified virial-type model.

  13. An Effective Novel ReactionSystem For The Photo-Degradation of Aqueous Organic Pollutants

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A novel reaction system consisted of a supported TiO2 film electrode, a Ru-Ti oxide film electrode and air (oxygen) electrode is reported. The air (oxygen) electrode can provide H2O2 continuously for homogeneous photochemical oxidation reaction on the spot. In this reactor, degradation reaction of aniline occur from interface of TiO2 film to ail solution which is irradiated by ultraviolet ray. The degradation rate of aniline was characterized by measuring the change of chemical oxygen demand (COD) in solution under different conditions. It was found that the degradation rate of aniline in the novel system increased apparently as compared with single heterogeneous photocatalysis and homogeneous photochemistry system. It can be explained in terms of combining acts of heterogeneous photocatalysis and homogeneous photochemistry.

  14. Aqueous systems of ethanolamine hydrochlorides and of chlorides of cerium, terbium, dysprosium, erbium

    International Nuclear Information System (INIS)

    The isothermal method of cross sections has been used to study the solubility at 25 and 50 deg C in ternary water-salt systems consisting of cerium chloride and mono-(1), di-(2) and triethanolamine (3) hydrochlorides as well as diethanolamine hydrochloride and terbium, dysprosium and erbium chlorides. Solubility isotherms testify to the formation in the system (1) of a congruently dissolved compound of the CeCl3x2(C2H4OHNN2HCl)x2H2O composition. Individual peculiarities of a new solid phase are proved by the DTA method by means of derivatograph ODL-106, while the composition is confirmed by chemical analysis. The rest of the systems - are of simple eutonic type

  15. Large-scale tests of aqueous scrubber systems for LMFBR vented containment

    International Nuclear Information System (INIS)

    Six large-scale air cleaning tests performed in the Containment Systems Test Facility (CSTF) are described. The test conditions simulated those postulated for hypothetical accidents in an LMFBR involving containment venting to control hydrogen concentration and containment overpressure. Sodium aerosols were generated by continously spraying sodium into air and adding steam and/or carbon dioxide to create the desired Na2O2, Na2CO3 or NaOH aerosol. Two air cleaning systems were tested: (a) spray quench chamber, educator venturi scrubber and high efficiency fibrous scrubber in series; and (b) the same except with the spray quench chamber eliminated. The gas flow rates ranged up to 0.8 m3/s (1700 acfm) at temperatures to 3130C (6000F). Quantities of aerosol removed from the gas stream ranged up to 700 kg per test. The systems performed very satisfactorily with overall aerosol mass removal efficiencies exceeding 99.9% in each test

  16. Characterization of aqueous two phase systems by combining lab-on-a-chip technology with robotic liquid handling stations.

    Science.gov (United States)

    Amrhein, Sven; Schwab, Marie-Luise; Hoffmann, Marc; Hubbuch, Jürgen

    2014-11-01

    Over the last decade, the use of design of experiment approaches in combination with fully automated high throughput (HTP) compatible screenings supported by robotic liquid handling stations (LHS), adequate fast analytics and data processing has been developed in the biopharmaceutical industry into a strategy of high throughput process development (HTPD) resulting in lower experimental effort, sample reduction and an overall higher degree of process optimization. Apart from HTP technologies, lab-on-a-chip technology has experienced an enormous growth in the last years and allows further reduction of sample consumption. A combination of LHS and lab-on-a-chip technology is highly desirable and realized in the present work to characterize aqueous two phase systems with respect to tie lines. In particular, a new high throughput compatible approach for the characterization of aqueous two phase systems regarding tie lines by exploiting differences in phase densities is presented. Densities were measured by a standalone micro fluidic liquid density sensor, which was integrated into a liquid handling station by means of a developed generic Tip2World interface. This combination of liquid handling stations and lab-on-a-chip technology enables fast, fully automated, and highly accurate density measurements. The presented approach was used to determine the phase diagram of ATPSs composed of potassium phosphate (pH 7) and polyethylene glycol (PEG) with a molecular weight of 300, 400, 600 and 1000 Da respectively in the presence and in the absence of 3% (w/w) sodium chloride. Considering the whole ATPS characterization process, two complete ATPSs could be characterized within 24h, including four runs per ATPS for binodal curve determination (less than 45 min/run), and tie line determination (less than 45 min/run for ATPS preparation and 8h for density determination), which can be performed fully automated over night without requiring man power. The presented methodology provides

  17. Experimental and theoretical approach to cationic drug-anionic gemini surfactant systems in aqueous medium.

    Science.gov (United States)

    Noori, Sahar; Naqvi, Andleeb Z; Ansari, Wajid H; Kabir-ud-Din

    2014-03-01

    Herein the results of surface tension measurements on the mixed systems of an amphiphilic drug amitriptyline hydrochloride (AMT) and three anionic bisphosphodiester gemini surfactants having different hydrophobic tails (8, 10, and 12 carbon) are presented. The experimental and ideal critical micelle concentration (cmc and cmcid) values suggest synergism in mixed systems of AMT and 8-2-8/10-2-10 and attractive interaction in AMT-12-2-12 systems. Other parameters evaluated from the data also suggest mixed micellization among the components with almost 50% contribution of surfactants (micellar mole fraction, X1(m), close to 0.5). The X1 values evaluated from Rubingh's model (X1(m)) and Motomura's model (X1(M)) as well as X1(id) values increase with increasing content of surfactants in solution. Adsorption behavior too indicates that the mixed monolayers experience attractive interaction (β(σ)) which vary in the order: AMT-12-2-12gemini is most compatible in this system. PMID:24333555

  18. Solubility in aqueous system of potassium sulfate, cadmium sulfate at 50 deg C

    International Nuclear Information System (INIS)

    Solubility in system potassium sulfate-cadmium sulfate-water at 50 deg C is studied using isothermal method. Crystallization limits of K2SO4, CdSO4x8/3H2O double salt 2K2SO4x2CdSO4x3H2O at 50 deg C are determined

  19. Controlled and reversible induction of differentiation and activation of adult human hepatocytes by a biphasic culture technique

    Institute of Scientific and Technical Information of China (English)

    Marcus K.H. Auth; Wolf-Otto Bechstein; Roman A. Blaheta; Kim A. Boost; Kerstin Leckel; Wolf-Dietrich Beecken; Tobias Engl; Dietger Jonas; Elsie Oppermann; Philip Hilgard; Bernd H. Markus

    2005-01-01

    AIM: Clinical application of human hepatocytes (HC) is hampered by the progressive loss of growth and differentiation in vitro. The object of the study was to evaluate the effect of a biphasic culture technique on expression and activation of growth factor receptors and differentiation of human adult HC.METHODS: Isolated HC were sequentially cultured in a hormone enriched differentiation medium (DM) containing nicotinamide, insulin, transferrin, selenium, and dexamethasone or activation medium (AM) containing hepatocyte growth factor (HGF), epidermal growth factor (EGF), andgranulocyte-macrophage colony-stimulating factor (GMCSF). Expression, distribution and activation of the HC receptors (MET and EGFR) and the pattern of characteristic cytokeratin (CK) filaments were measured by fluorometry, confocal microscopy and Western blotting.RESULTS: In the biphasic culture system, HC underwent repeated cycles of activation (characterized by expression and activation of growth factor receptors) and re-differentiation (illustrated by distribution of typical filaments CK-18 but low or absent expression of CK-19). In AM increased expression of MET and EGFR was associated with receptor translocation into the cytoplasm and induction of atypical CK-19. In DM low expression of MET and EGFR was localized on the cell membrane and CK-19 was reduced. Receptor phosphorylation required embedding of HC in collagen type Ⅰ gel.CONCLUSION: Control and reversible modulation of growth factor receptor activation of mature human HC can be accomplishedin vitro, when defined signals from the extracellular matrix and sequential growth stimuli are provided. The biphasic technique helps overcome dedifferentiation, which occurs during continuous stimulation by means of growth factors.

  20. Surface tension and rheology of aqueous dispersed systems containing a new hydrophobically modified polymer and surfactants.

    Science.gov (United States)

    Claro, Carmen; Muñoz, José; de la Fuente, Julia; Jiménez-Castellanos, María Rosa; Lucero, María Jesús

    2008-01-22

    This article reports data supporting that the hydroxypropyl cellulose-methyl methacrylate (HCMMA) hydrophobically modified polymer studied is surface-active at the air-water interface due to its amphiphilic nature. Surface tension measurements of diluted solutions point to the formation of a complex between this copolymer and a polyoxyethylene nonylphenyl ether non-ionic surfactant of high HLB. Conversely, no indications of specific interactions were found either with a polyoxyethylene nonylphenyl ether non-ionic surfactant of intermediate HLB or with an anionic surfactant such as sodium dodecyl sulfate (SDS). The physical stability of such dispersions depended on the surfactant used. The HCMMA/SDS systems studied showed phase separation shortly after preparation, while the dispersions with the non-ionic surfactant of higher HLB exhibited at least short-term stability and Newtonian behaviour. Foam-like dispersions of HCMMA-surfactant systems with intermediate HLB presented long-term stability, underlying the important role of hydrophobic interactions in these systems. One of the latter dispersions and the corresponding continuous phase were rheologically characterised by small amplitude oscillatory shear and flow curve experiments and exhibited a high Newtonian viscosity up to a critical shear stress followed by a shear thinning as well as weak-gel viscoelastic properties. The results obtained support that (a) the continuous phase presents a complex microstructure, which required the use of a serrated sensor system to avoid the occurrence of wall depletion phenomena, (b) it controls the rheology of the whole dispersion and (c) the latter showed both physical stability and rheological properties suitable for applications as controlled release systems in pharmacy or cosmetics. PMID:17693044

  1. Biphasic influence of dexamethasone exposure on embryonic vertebrate skeleton development

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Xin; Chen, Jian-long; Ma, Zheng-lai; Zhang, Zhao-long; Lv, Shun; Mai, Dong-mei; Liu, Jia-jia [Department of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Medicine, Jinan University, Guangzhou 510632 (China); Chuai, Manli [Division of Cell and Developmental Biology, University of Dundee, Dundee DD1 5EH (United Kingdom); Lee, Kenneth Ka Ho; Wan, Chao [Stem Cell and Regeneration Thematic Research Programme, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin (Hong Kong); Yang, Xuesong, E-mail: yang_xuesong@126.com [Department of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Medicine, Jinan University, Guangzhou 510632 (China); Institute of Fetal-Preterm Labor Medicine, Jinan University, Guangzhou 510632 (China)

    2014-11-15

    increased in mesenchymal cell mass treated by low concentration of Dex. Mmp-13 expression was obviously up-regulated by Dex in both mesenchymal cells and primary chondrocyte cultures. And Col10a1 expression was also increased by Dex exposure in chondrocyte. In summary, we have revealed that different concentrations of Dex exposure during early gestation could exert a biphasic effect on vertebrate skeletal development. - Highlights: • Chick embryos occurred shortening of the long bone following Dex exposure. • Dex suppressed chondrocytes proliferation and promoted apoptosis. • Dex exposure decreased ALP production and up-regulated Runx-2 and Mmp-13. • Dex exhibited biphasic effects on chondrogenic proliferation and nodule formation. • The hypertrophy and ossification were accelerated by Dex both in vivo and in vitro.

  2. Biphasic influence of dexamethasone exposure on embryonic vertebrate skeleton development

    International Nuclear Information System (INIS)

    mesenchymal cell mass treated by low concentration of Dex. Mmp-13 expression was obviously up-regulated by Dex in both mesenchymal cells and primary chondrocyte cultures. And Col10a1 expression was also increased by Dex exposure in chondrocyte. In summary, we have revealed that different concentrations of Dex exposure during early gestation could exert a biphasic effect on vertebrate skeletal development. - Highlights: • Chick embryos occurred shortening of the long bone following Dex exposure. • Dex suppressed chondrocytes proliferation and promoted apoptosis. • Dex exposure decreased ALP production and up-regulated Runx-2 and Mmp-13. • Dex exhibited biphasic effects on chondrogenic proliferation and nodule formation. • The hypertrophy and ossification were accelerated by Dex both in vivo and in vitro

  3. Extraction of natural red colorants from the fermented broth of Penicillium purpurogenum using aqueous two-phase polymer systems.

    Science.gov (United States)

    Santos-Ebinuma, Valéria Carvalho; Lopes, André Moreni; Pessoa, Adalberto; Teixeira, Maria Francisca Simas

    2015-01-01

    Safety concerns related to the increasing and widespread application of synthetic coloring agents have increased the demand for natural colorants. Fungi have been employed in the production of novel and safer colorants. In order to obtain the colorants from fermented broth, suitable extraction systems must be developed. Aqueous two-phase polymer systems (ATPPS) offer a favorable chemical environment and provide a promising alternative for extracting and solubilizing these molecules. The aim of this study was to investigate the partitioning of red colorants from the fermented broth of Penicillium purpurogenum using an ATPPS composed of poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA). Red colorants partitioned preferentially to the top (PEG-rich phase). In systems composed of PEG 6,000 g/mol/NaPA 8,000 g/mol, optimum colorant partition coefficient (KC ) was obtained in the presence of NaCl 0.1 M (KC  = 10.30) while the PEG 10,000 g/mol/NaPA 8,000 g/mol system in the presence of Na2 SO4 0.5 M showed the highest KC (14.78). For both polymers, the mass balance (%MB) and yield in the PEG phase (%ηTOP ) were close to 100 and 79%, respectively. The protein selectivity in all conditions evaluated ranged from 2.0-3.0, which shows a suitable separation of the red colorants and proteins present in the fermented broth. The results suggest that the partitioning of the red colorants is dependent on both the PEG molecular size and salt type. Furthermore, the results obtained support the potential application of ATPPS as the first step of a purification process to recover colorants from fermented broth of microorganisms. PMID:26097197

  4. Fluid sample collection and distribution system. [qualitative analysis of aqueous samples from several points

    Science.gov (United States)

    Brooks, R. L. (Inventor)

    1979-01-01

    A multipoint fluid sample collection and distribution system is provided wherein the sample inputs are made through one or more of a number of sampling valves to a progressive cavity pump which is not susceptible to damage by large unfiltered particles. The pump output is through a filter unit that can provide a filtered multipoint sample. An unfiltered multipoint sample is also provided. An effluent sample can be taken and applied to a second progressive cavity pump for pumping to a filter unit that can provide one or more filtered effluent samples. The second pump can also provide an unfiltered effluent sample. Means are provided to periodically back flush each filter unit without shutting off the whole system.

  5. Cell separation in immunoaffinity partition in aqueous polymer two-phase systems

    Science.gov (United States)

    Karr, Laurel J.; Van Alstine, James M.; Snyder, Robert S.; Shafer, Steven G.; Harris, J. Milton

    1989-01-01

    Two methods for immunoaffinity partitioning are described. One technique involves the covalent coupling of poly (ethylene glycol) (PEG) to immunoglobulin G antibody preparations. In the second method PEG-modified Protein A is used to complex with cells and unmodified antibody. The effects of PEG molecular weight, the degree of modification, and varying phase system composition on antibody activity and its affinity for the upper phase are studied. It is observed that both methods resulted in effective cell separation.

  6. Antioxidant potential of aqueous extract of some food grain powder in meat model system

    OpenAIRE

    Yogesh, K.; Jha, S. N.; Ahmad, Tanbir

    2012-01-01

    In-vitro antioxidant activity of some food grains [sprouted mung bean (Vigna radiata), mung bean, sprouted chana (Cicer arietinum), chana, corn (Zea mays), methi (Trigonella foenum-graecum) and rajma (Phaseolus vulgaris)] powder extracts (FGE) was estimated by DPPH free radical scavenging activity (SA) method. Total phenolics and reducing power were also estimated in these extracts. The antioxidant potential of these extracts was also estimated in a meat model system. Total phenolics in FGE r...

  7. Chemical analysis of multicomponent aqueous solutions using a system of nonselective sensor and artificial neural networks

    International Nuclear Information System (INIS)

    With the aim of creating a multisensor system for determining heavy-metal cations (Cu2+, Pb2+, Cd2+, and Zn2+) and inorganic anions (Cl-, F-, and SO42-), measurements in mixed solutions were carried out with the use of an array of sensors based on chalcogenide glass electrodes, and the possibility of using various methods of mathematical processing of the resulting intricate signals was studied. Three methods of data processing were used: multilinear regression, partial least squares, and artificial neural networks. It was found that the multisensor system proposed were suitable for determining all of the analytes with an accuracy of 1-10%. Because the responses of sensors in solutions of complex composition deviated from linearity, the lowest determination errors were obtained with the use of an artificial neural network. As to the method of data securing (nonselective response of a sensor array) and processing (artificial neural network), the multisensor system developed may be considered a prototype of a device of the electronic tongue type

  8. Oscillatory three-phase flow reactor for studies of bi-phasic catalytic reactions.

    Science.gov (United States)

    Abolhasani, Milad; Bruno, Nicholas C; Jensen, Klavs F

    2015-05-28

    A multi-phase flow strategy, based on oscillatory motion of a bi-phasic slug within a fluorinated ethylene propylene (FEP) tubular reactor, under inert atmosphere, is designed and developed to address mixing and mass transfer limitations associated with continuous slug flow chemistry platforms for studies of bi-phasic catalytic reactions. The technique is exemplified with C-C and C-N Pd catalyzed coupling reactions. PMID:25876959

  9. A simulation study of the reaction of human heart to biphasic electrical shocks

    OpenAIRE

    Seemann Gunnar; Popp lulia M; Dössel Olaf

    2004-01-01

    Abstract Background This article presents a study, which examines the effects of biphasic electrical shocks on human ventricular tissue. The effects of this type of shock are not yet fully understood. Animal experiments showed the superiority of biphasic shocks over monophasic ones in defibrillation. A mathematical computer simulation can increase the knowledge of human heart behavior. Methods The research presented in this article was done with different models representing a three-dimension...

  10. Oscillatory three-phase flow reactor for studies of bi-phasic catalytic reactions

    OpenAIRE

    Abolhasani, Milad; Bruno, Nicholas C.; Jensen, Klavs F.

    2015-01-01

    A multi-phase flow strategy, based on oscillatory motion of a bi-phasic slug within a fluorinated ethylene propylene (FEP) tubular reactor, under inert atmosphere, is designed and developed to address mixing and mass transfer limitations associated with continuous slug flow chemistry platforms for studies of bi-phasic catalytic reactions. The technique is exemplified with C–C and C–N Pd catalyzed coupling reactions.

  11. Laser heating of aqueous samples on a micro-optical-electro-mechanical system

    Science.gov (United States)

    Beer, Neil Reginald; Kennedy, Ian

    2013-02-05

    A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channel wherein the carrier fluid is not appreciably heated by the laser beam.

  12. Preparation, spectrometric analysis and determination of the electrochemical transport characteristics of uranium (IV) in aqueous systems

    International Nuclear Information System (INIS)

    A process for the quantitative development of uranium-(IV) solutions in nitric and perchloric acid media was developed. After appropriate concentration setting of the solutions, the conductivity of the uranium (IV) in the dependence on concentration were analysed. The conversion of the measuring results on the standard system water was done by means of a conductivity theory; this allows a comparison with the conductivity data of other ions. The conductivity calculated, at an ion strength I tending to zero, provided the suitable data for the ion mobility and the transference number. (orig./PW)

  13. R7T7 glass alteration mechanism in an aqueous closed system: understanding and modelling the long term alteration kinetic

    International Nuclear Information System (INIS)

    The long term alteration rate of the French R7T7 nuclear glass has been investigated since many years because it will define the overall resistance of the radionuclide containment matrix. Recent studies have shown that the final rate remains constant or is slightly decreasing with time. It never reaches zero. Though this residual rate is very low, only 5 nm per year at 50 C, it would be the dominant alteration phenomenon in a geological repository. Two mechanisms are suggested for explaining such behaviour: diffusion in solution of elements from glass through an amorphous altered layer and precipitation of neo-formed phases. The diffusion processes are in agreement with a solid state diffusion mechanism and can lead to secondary phase precipitation due to solution concentration increases. Observed phases are mainly phyllosilicates and zeolites, in specific conditions. Phyllosilicates are expected to maintain the residual kinetic rate whereas alteration resumption could be observed in presence of zeolites at very high pH or temperature (10.5 at 90 C or temperature above 150 C). Both diffusion and neo-formed phase precipitation have been investigated in order to better understand their impact on the residual alteration rate and have then been modelled by a calculation code, coupling chemistry and transport, in order to be able to better anticipate the long term behaviour of the glass R7T7 in an aqueous closed system. (author)

  14. Separation of porcine parvovirus from bovine serum albumin using PEG-salt aqueous two-phase system.

    Science.gov (United States)

    Vijayaragavan, K Saagar; Zahid, Amna; Young, Jonathan W; Heldt, Caryn L

    2014-09-15

    Vaccine production faces a challenge in adopting conventional downstream processing steps that can efficiently purify large viral particles. Some major issues that plague vaccine purification are purity, potency, and quality. The industry currently considers 30% as an acceptable virus recovery for a vaccine purification process, including all downstream processes, whereas antibody recovery from CHO cell culture is generally around 80-85%. A platform technology with an improved virus recovery would revolutionize vaccine production. In a quest to fulfill this goal, we have been exploring aqueous two-phase systems (ATPSs) as an optional mechanism to purify virus. ATPS has been unable to gain wide implementation mainly due to loss of virus infectivity, co-purification of proteins, and difficulty of polymer recycling. Non-enveloped viruses are chemically resistant enough to withstand the high polymer and salt concentrations that are required for effective ATPS separations. We used infectious porcine parvovirus (PPV), a non-enveloped, DNA virus as a model virus to test and develop an ATPS separation method. We successfully tackled two of the three main disadvantages of ATPS previously stated; we achieved a high infectious yield of 64% in a PEG-citrate ATPS process while separating out the main contaminate protein, bovine serum albumin (BSA). The most dominant forces in the separation were biomolecule charge, virus surface hydrophobicity, and the ATPS surface tension. Highly hydrophobic viruses are likely to benefit from the discovered ATPS for high-purity vaccine production and ease of implementation. PMID:25086421

  15. Modeling Pb (II) adsorption from aqueous solution by ostrich bone ash using adaptive neural-based fuzzy inference system.

    Science.gov (United States)

    Amiri, Mohammad J; Abedi-Koupai, Jahangir; Eslamian, Sayed S; Mousavi, Sayed F; Hasheminejad, Hasti

    2013-01-01

    To evaluate the performance of Adaptive Neural-Based Fuzzy Inference System (ANFIS) model in estimating the efficiency of Pb (II) ions removal from aqueous solution by ostrich bone ash, a batch experiment was conducted. Five operational parameters including adsorbent dosage (C(s)), initial concentration of Pb (II) ions (C(o)), initial pH, temperature (T) and contact time (t) were taken as the input data and the adsorption efficiency (AE) of bone ash as the output. Based on the 31 different structures, 5 ANFIS models were tested against the measured adsorption efficiency to assess the accuracy of each model. The results showed that ANFIS5, which used all input parameters, was the most accurate (RMSE = 2.65 and R(2) = 0.95) and ANFIS1, which used only the contact time input, was the worst (RMSE = 14.56 and R(2) = 0.46). In ranking the models, ANFIS4, ANFIS3 and ANFIS2 ranked second, third and fourth, respectively. The sensitivity analysis revealed that the estimated AE is more sensitive to the contact time, followed by pH, initial concentration of Pb (II) ions, adsorbent dosage, and temperature. The results showed that all ANFIS models overestimated the AE. In general, this study confirmed the capabilities of ANFIS model as an effective tool for estimation of AE. PMID:23383640

  16. Use of metal complexation in non-aqueous capillary electrophoresis systems for the separation and improved detection of tetracyclines.

    Science.gov (United States)

    Tjørnelund, J; Hansen, S H

    1997-08-29

    Metal complexation in non-aqueous capillary electrophoresis systems was evaluated for the separation and improved detection of tetracycline antibiotics using laser-induced fluorescence detection. It was found that three factors were important for the choice of complexing agent: (i) it should be soluble in the organic solvent used for the separation, (ii) it should have a sufficient fast complexing rate so as not to invalidate the electrophoretic separation and, (iii) it should give a large increase in the fluorescence intensity. Mg2+ ions were found to be the most suitable ions for the separation of the tetracyclines as the acetate salt of magnesium is very soluble in organic solvents and only a relatively low current was generated during electrophoresis making it possible to use high concentrations of the complexing metal ion. Metal complexation strongly intensified the fluorescence of tetracyclines and all organic solvents investigated further intensified the fluorescence, e.g. dimethylformamide improved the fluorescence of the oxytetracycline metal complex by a factor of 34 compared to water. However, magnesium acetate was not sufficiently soluble in dimethylformamide and therefore N-methylformamide, improving the fluorescence intensity by only a factor of 9, was used. It was demonstrated that the method can be used for the detection of tetracyclines at the ppb level in milk and plasma. PMID:9335125

  17. Development of green betaine-based deep eutectic solvent aqueous two-phase system for the extraction of protein.

    Science.gov (United States)

    Li, Na; Wang, Yuzhi; Xu, Kaijia; Huang, Yanhua; Wen, Qian; Ding, Xueqin

    2016-05-15

    Six kinds of new type of green betaine-based deep eutectic solvents (DESs) have been synthesized. Deep eutectic solvent aqueous two-phase systems (DES-ATPS) were established and successfully applied in the extraction of protein. Betaine-urea (Be-U) was selected as the suitable extractant. Single factor experiments were carried out to determine the optimum conditions of the extraction process, such as the salt concentration, the mass of DES, the separation time, the amount of protein, the temperature and the pH value. The extraction efficiency could achieve to 99.82% under the optimum conditions. Mixed sample and practical sample analysis were discussed. The back extraction experiment was implemented and the back extraction efficiency could reach to 32.66%. The precision experiment, repeatability experiment and stability experiment were investigated. UV-vis, FT-IR and circular dichroism (CD) spectra confirmed that the conformation of protein was not changed during the process of extraction. The mechanisms of extraction were researched by dynamic light scattering (DLS), the measurement of the conductivity and transmission electron microscopy (TEM). DES-protein aggregates and embraces phenomenon play considerable roles in the separation process. All of these results indicated that betaine-based DES-ATPS may provide a potential substitute new method for the separation of proteins. PMID:26992491

  18. Chemical relevance of the copper(II)— L-carnosine system in aqueous solution: A thermodynamic and spectrophotometric study

    Science.gov (United States)

    Daniele, Pier G.; Prenesti, Enrico; Zelano, Vincenzo; Ostacoli, Giorgio

    1993-08-01

    The copper(II)— L-carnosine (L -) system has been re-investigated in aqueous solution, at I = 0.1 mol dm -1, different temperatures (5⩽ t⩽45°C) and with metal to ligand ratios ranging from 3:1 to 1:3. Both potentiometry and visible spectrophotometry were employed. From an overall consideration of all experiments, [CuLH] 2+, [CuL] +, [CuLH -1]°, [Cu 2L 2H -2]° and [Cu 2LH -1] 2+ were recognized as the species which provide the best interpretation of experimental data. The complex formation constants, determined at different temperatures, allowed us to obtain reliable values of Δ H° and good estimates of Δ C° p. From visible spectrophotometric measurements, carried out at different pH and metal to ligand ratios, it was possible to calculate the electronic spectrum of each complex formed in solution. A structure is also proposed for each species, on the basis of thermodynamic and spectral results.

  19. Adsorption of La(III) in aqueous systems by N-(2-hydroxyethyl) salicylaldimine-functionalized mesoporous silica

    Energy Technology Data Exchange (ETDEWEB)

    Tadjarodi, Azadeh, E-mail: tajarodi@iust.ac.ir; Jalalat, Vahideh; Zare-Dorabei, Rouholah

    2015-01-15

    Highlights: • HESI-SBA-15 as a new adsorbent was synthesized for the first time. • This adsorbent was selective for lanthanum ion removal in presence of other ions. • The factors that affected adsorption of La(III) in aqueous solution were studied. • La{sup 3+} uptake process was according to pseudo-second-order kinetic model. - Abstract: In this work, a novel modified SBA-15 with covalently bonded N-(2-hydroxyethyl) salicylaldimine Schiff base as a ligand (HESI-SBA-15) was successfully synthesized, characterized and used as a selective absorbent for lanthanum ions removal from water systems. The structure and physicochemical properties were identified by elemental analysis, X-ray diffraction, nitrogen adsorption–desorption, thermogravimetric analysis and FTIR spectroscopy, scanning electron microscopy, BET surface area and BJH pore size. These techniques have confirmed that the Schiff base ligand was successfully grafted on the SBA-15 surface and ordered arrangement of the silica support was preserved under functionalization. The effect of pH, adsorbent dose, contact time, ionic strength and initial metal ions concentration were studied by using a batch method. This new adsorbent showed high adsorption capacity and selectivity for lanthanum in the presence of other ions. The adsorption process was exactly according to the pseudo-second-order kinetic model. The adsorbent showed a good reusability after four cycles recovery.

  20. Biphasic flow: structure and upscaling, consequences on macroscopic transport properties

    CERN Document Server

    Toussaint, Renaud; Méheust, Yves; Løvoll, Grunde; Jankov, Mihailo; Schäfer, Gerhard; Schmittbuhl, Jean

    2012-01-01

    In disordered porous media, two-phase flow of immiscible fluids (biphasic flow) is organized in patterns that sometimes exhibit fractal geometries over a range of length scales, depending on the capillary, gravitational and viscous forces at play. These forces, as well as the boundary conditions, also determine whether the flow leads to the appearance of fingering pathways, i.e., unstable flow, or not. We present here a short review of these aspects, focusing on drainage and summarizing when these flows are expected to be stable or not, what fractal dimensions can be expected, and in which range of scales. We base our review on experimental studies performed in two-dimensional Hele-Shaw cells, or addressing three dimensional porous media by use of several imaging techniques. We first present configurations in which solely capillary forces and gravity play a role. Next, we review configurations in which capillarity and viscosity are the main forces at play. Eventually, we examine how the microscopic geometry o...

  1. Biphasic oxidation of oxy-hemoglobin in bloodstains.

    Directory of Open Access Journals (Sweden)

    Rolf H Bremmer

    Full Text Available BACKGROUND: In forensic science, age determination of bloodstains can be crucial in reconstructing crimes. Upon exiting the body, bloodstains transit from bright red to dark brown, which is attributed to oxidation of oxy-hemoglobin (HbO(2 to met-hemoglobin (met-Hb and hemichrome (HC. The fractions of HbO(2, met-Hb and HC in a bloodstain can be used for age determination of bloodstains. In this study, we further analyze the conversion of HbO(2 to met-Hb and HC, and determine the effect of temperature and humidity on the conversion rates. METHODOLOGY: The fractions of HbO(2, met-Hb and HC in a bloodstain, as determined by quantitative analysis of optical reflectance spectra (450-800 nm, were measured as function of age, temperature and humidity. Additionally, Optical Coherence Tomography around 1300 nm was used to confirm quantitative spectral analysis approach. CONCLUSIONS: The oxidation rate of HbO(2 in bloodstains is biphasic. At first, the oxidation of HbO(2 is rapid, but slows down after a few hours. These oxidation rates are strongly temperature dependent. However, the oxidation of HbO(2 seems to be independent of humidity, whereas the transition of met-Hb into HC strongly depends on humidity. Knowledge of these decay rates is indispensable for translating laboratory results into forensic practice, and to enable bloodstain age determination on the crime scene.

  2. Biphasic Effect of Rifampicin on Bilirubin- A Case Report.

    Science.gov (United States)

    Gopi, Manigandan; Seshadri, Mandalam Subramanian

    2016-04-01

    Drug induced hepatitis is a major problem which a physician encounters in his clinical practice. In view of increasing incidence of tuberculosis in our country a large number of infected individuals are started on Antituberculous (ATT) drugs and rifampicin is invariably part of the regimen. One of the major adverse effects of ATT drugs is drug- induced hepatitis which is characterized by elevation of liver enzymes and bilirubin. Hepatotoxicity is usually idiosyncratic or dose-dependent. Rifampicin causes transient elevation of transaminases in 10-20 percent of individuals and this does not warrant dose adjustments of the drug. Rarely rifampicin can lead to severe hepatitis with hyperbilirubinaemia and marked elevations of SGOT and SGPT and in some patients this can be fatal. The exact mechanism of Rifampicin induced hepatotoxicity is not known but it is postulated to be due to idiosyncratic reaction to rifampicin metabolites which may be directly toxic or induce an immunologically mediated liver injury. Rarely rifampicin may cause hyperbilirubinaemia without enzyme elevation. Here we report a patient with bilateral pulmonary tuberculosis who developed transient severe indirect hyperbilirubinaemia on rifampicin. On review of relevant literature we find that rifampicin can have a biphasic effect on bilirubin, an initial increase in indirect bilirubin and later normalization of bilirubin. We have reported this case because of its rarity in clinical practice. PMID:27190870

  3. Interaction in aqueous systems containing indium trichloride, hydrogen sulfide and hydrochloric acid

    International Nuclear Information System (INIS)

    On the basis of experimental data on α-In2S3 solubility in hydrochloric solutions the standard value of the Gibbs formation energy of crystal In2S3 (-351.96±5.87 kJ/mol) was refined. The value of solubility product (SP) of crystal indium (3) sulfide, lg SP In2S3 = -75.6 (μ = 0, t = 25 deg C), was obtained. By the methods of physicochemical computer simulation equilibrium composition of the system InCl3-HCl-H2S-H2O at 25, 50, 75 deg C, hydrogen sulfide partial pressure from 103 to 105 Pa, hydrochloric acid concentration 0.01-0.5 mol/lg H2O was determined. Indium phase diagrams in hydrochloric solutions were plotted

  4. Influence of saline solution on hydration behavior of β-dicalcium silicate in comparison with biphasic calcium phosphate/hydroxyapatite bio-ceramics

    International Nuclear Information System (INIS)

    The influence of using saline solution as mixing and curing liquid on some characteristics of β-dicalcium silicate (β-C2S) and biphasic compound tri-calcium phosphate/hydroxyapatite (TCP/HAp) bio-ceramics was investigated. β-C2S (27–30 nm) was prepared by solid state reaction at 1450 °C, while biphasic compound TCP/HAp (7–15 nm) was synthesized from an aqueous solution of Ca(NO3)2·4H2O and (NH4)2HPO4·12H2O by chemical precipitation method. Setting times, compressive strength, pH values, X-ray diffraction analysis, infrared spectroscopy, scanning electron microscopy (SEM) were investigated. The evaluation of cytotoxicity of both calcium silicate and biphasic compounds to human gingival fibroblasts was carried out. The use of saline solution as mixing and immersing liquid shortened the setting time for the two bio-cements. TCP/HAp did not show any mechanical strength but β-C2S showed good strength values. Both synthesized compounds showed a moderate cytotoxicity and both materials were effective in a no significant way. - Highlights: • The dissolution and hydration of β-C2S and TCP/HAp in distilled water and saline solution were studied. • TCP/HAp did not show mechanical strength, while β-C2S showed good mechanical strength. • The use of saline solution did enhances the dissolution & hydration rate. • An increase in pH values was detected when using saline solution. • Both materials showed a moderate cytotoxicity in no significant way

  5. Influence of saline solution on hydration behavior of β-dicalcium silicate in comparison with biphasic calcium phosphate/hydroxyapatite bio-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Radwan, M.M., E-mail: mmahmoudradwan@yahoo.com [Ceramics Dept, National Research Centre, Cairo (Egypt); Abd El-Hamid, H.K. [Ceramics Dept, National Research Centre, Cairo (Egypt); Mohamed, A.F. [The Holding Company for Production of Vaccines, Sera and Drugs (EGYVAC) (Egypt)

    2015-12-01

    The influence of using saline solution as mixing and curing liquid on some characteristics of β-dicalcium silicate (β-C{sub 2}S) and biphasic compound tri-calcium phosphate/hydroxyapatite (TCP/HAp) bio-ceramics was investigated. β-C{sub 2}S (27–30 nm) was prepared by solid state reaction at 1450 °C, while biphasic compound TCP/HAp (7–15 nm) was synthesized from an aqueous solution of Ca(NO{sub 3}){sub 2}·4H{sub 2}O and (NH{sub 4}){sub 2}HPO{sub 4}·12H{sub 2}O by chemical precipitation method. Setting times, compressive strength, pH values, X-ray diffraction analysis, infrared spectroscopy, scanning electron microscopy (SEM) were investigated. The evaluation of cytotoxicity of both calcium silicate and biphasic compounds to human gingival fibroblasts was carried out. The use of saline solution as mixing and immersing liquid shortened the setting time for the two bio-cements. TCP/HAp did not show any mechanical strength but β-C{sub 2}S showed good strength values. Both synthesized compounds showed a moderate cytotoxicity and both materials were effective in a no significant way. - Highlights: • The dissolution and hydration of β-C{sub 2}S and TCP/HAp in distilled water and saline solution were studied. • TCP/HAp did not show mechanical strength, while β-C{sub 2}S showed good mechanical strength. • The use of saline solution did enhances the dissolution & hydration rate. • An increase in pH values was detected when using saline solution. • Both materials showed a moderate cytotoxicity in no significant way.

  6. Phytoremediation of chlorpyrifos in aqueous system by riverine macrophyte, Acorus calamus: toxicity and removal rate.

    Science.gov (United States)

    Wang, Qinghai; Li, Cui; Zheng, Ruilun; Que, Xiaoe

    2016-08-01

    The potential of Acorus calamus to remove chlorpyrifos from water was assessed under laboratory conditions. Toxic effects of the insecticide in A. calamus were evaluated using pulse-amplitude modulated chlorophyll fluorescence techniques as well. At exposure concentrations above 8 mg L(-1), A. calamus showed obvious phytotoxic symptom with significant reduction in quantum efficiency of PSII (ΦPSII) and photochemical quenching coefficient (qP) in 20-day test; the inhibition of maximal quantum efficiency of PSII (Fv/Fm) was accompanied by a significant rise in initial chlorophyll fluorescence (Fo) within 15-day exposures. Fv/Fm and Fo recover to the normal level after 20-day exposure. The reduced removal rate to chlorpyrifos was observed with increase of initial chlorpyrifos concentrations. At application levels of 1, 2, and 4 mg L(-1), the disappearance rate of chlorpyrifos in the hydroponic system with plants was significantly greater than that without plants during the 20-day test periods. Chlorpyrifos was taken up from medium and transferred to above ground tissues by the plant and significant amounts of chlorpyrifos accumulated in plant tissues. The result indicated that A. calamus can promote the disappearance of chlorpyrifos from water and may be used for phytoremediation of water contaminated with a relatively low concentration of chlorpyrifos insecticide (<4 mg L(-1)). PMID:27154841

  7. DNA hosted and aligned in aqueous interstitia of a lamellar liquid crystal – a membrane–biomacromolecule interaction model system

    KAUST Repository

    Carlsson, Nils

    2013-01-01

    We report that DNA molecules can be intercalated and macroscopically oriented in the aqueous interstitia of a lyotropic lamellar liquid crystal. Using UV-vis linear dichroism and fluorescence spectroscopy we show that double-stranded oligonucleotides (25 base pairs) in the water-octanoate-decanol system remain base-paired in the B conformation and are confined in two dimensions, with the helix axis preferentially parallel to the lipid bilayer surfaces but free to rotate within this plane. The degree of helix confinement and the corresponding 2-D orientation can be improved by decreasing the thickness of the water interstitia via the fraction of water in the ternary mixture. Not surprisingly, the corresponding single-stranded oligonucleotides are not aligned, with their persistence length being short in comparison to the lamellar interstitium thickness. We propose this as a model system for studying interactions of DNA-ligand complexes near a lipid bilayer membrane which we demonstrate by using dye probes that are either covalently attached to one end of the oligonucleotide or reversibly bound by intercalation between the base pairs. Three cationic dyes, all strongly bound by intercalation to DNA when free in solution, are found to not bind to DNA but to prefer the membrane surface. The covalently attached Cy5 also binds to the bilayer while Cy3 tends to end-stack to the oligonucleotide duplex. The orientation of Cy5 parallel to the membrane indicates that electrostatic surface binding predominates over insertion into the hydrophobic interior of the membrane. Anionic and zwitterionic dyes (FAM and ROX) are found to remain randomly oriented in the water between the lipid bilayer surfaces. © The Royal Society of Chemistry.

  8. Partitioning and purification of extracellular β-1,3-1,4-glucanase in aqueous two-phase systems

    Institute of Scientific and Technical Information of China (English)

    HE Guo-qing; ZHANG Xiu-yan; TANG Xing-jun; CHEN Qi-he; RUAN Hui

    2005-01-01

    The partition behaviors of β-1,3-1,4-glucanase, α-amylase and neutral proteases from clarified and whole fermentation broths of Bacillus subtilis ZJF-1A5 were investigated. An aqueous two-phase system (polyethylene glycol (PEG)/MgSO4)was examined with regard to the effects of PEG molecular weight (MW) and concentration, MgSO4 concentration, pH and NaCl concentration on enzyme partition and extraction. The MW and concentration of PEG were found to have significant effects on enzyme partition and extraction with low MW PEG showing the greatest benefit in the partition and extraction of β-glucanase with the PEG/MgSO4 system. MgSO4 concentration influenced the partition and extraction of β-glucanase significantly. pH had little effect on β-glucanase or proteases partition but affected α-amylase partition when pH was over 7.0. The addition of NaCl had little effect on the partition behavior of β-glucanase but had very significant effects on the partitioning of α-amylase and on the neutral proteases. The partition behaviors of β-glucanase, α-amylase and proteases in whole broth were also investigated and results were similar to those obtained with clarified fermentation broth. A two-step process for purifying β-glucanase was developed, which achieved β-glucanase recovery of 65.3% and specific activity of 14027 U/mg, 6.6 times improvement over the whole broth.

  9. Analytical capabilities of laboratory, benchtop and handheld X-ray fluorescence systems for detection of metals in aqueous samples pre-concentrated with solid-phase extraction disks

    Energy Technology Data Exchange (ETDEWEB)

    Margui, E., E-mail: eva.margui@udg.edu [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); Hidalgo, M. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); Queralt, I. [Laboratory of X-ray Analytical Applications, Institute of Earth Sciences ' Jaume Almera' , CSIC, Sole Sabaris s/n, 08028 Barcelona (Spain); Van Meel, K. [Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2640 Antwerp (Belgium); Fontas, C. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain)

    2012-01-15

    We aimed to achieve improved instrumental sensitivity and detection limits for the analysis of several elements (Cu, Ni, Zn, Pb and Cd) in aqueous samples with energy dispersive X-ray fluorescence spectrometry (EDXRF). The metals were pre-concentrated from aqueous solutions using commercially available organic-based solid-phase extraction (SPE) disks functionalized with iminodiacetate groups. These thin-layer organic materials provide an ideal support for XRF analysis. The elements were collected on the SPE extraction disks using a simple filtration procedure (starting with 1 L of aqueous sample) that allows direct XRF measurements to be performed in the field (in situ). We evaluated the analytical possibilities and drawbacks of using this pre-concentration procedure in combination with the following XRF configurations: a handheld unit, a benchtop EDXRF system and a high-energy polarized-beam EDXRF instrument (HE-P-EDXRF). Using the HE-P-EDXRF system, the detection limits for all metals were more than one order of magnitude lower than those attained using handheld and benchtop EDXRF instrumentation. For the detection of metal concentrations higher than {approx} 20 {mu}g/L, however, handheld or benchtop systems remain a very good option due to their extreme simplicity of operation and low-cost, compact design. We demonstrate the application of these methodologies, using the three equipment systems, to the analysis of trace concentrations of metals in different types of aqueous samples, including tap water and waste water. - Highlights: Black-Right-Pointing-Pointer Use of solid-phase extraction disks for pre-concentration of Cu, Ni, Zn, Pb and Cd. Black-Right-Pointing-Pointer Combination of this pre-concentration procedure with different XRF systems. Black-Right-Pointing-Pointer Successful application to trace metal determination in tap and waste water samples. Black-Right-Pointing-Pointer Direct measurements in the field are possible if a handheld unit is used.

  10. A Novel Aqueous Two Phase System Composed of Surfactant and Xylitol for the Purification of Lipase from Pumpkin (Cucurbita moschata Seeds and Recycling of Phase Components

    Directory of Open Access Journals (Sweden)

    Mehrnoush Amid

    2015-06-01

    Full Text Available Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was investigated. Moreover, the effect of system pH and crude load on the degree of purification and yield of the purified lipase were studied. The results indicated that the lipase was partitioned into the top surfactant rich phase while the impurities partitioned into the bottom xylitol-rich phase using an aqueous two phase system composed of 24% (w/w Triton X-100 and 20% (w/w xylitol, at 56.2% of tie line length (TLL, (TTL is one of the important parameters in this study and it is determined from a bimodal curve in which the tie-line connects two nodes on the bimodal, that represent concentration of phase components in the top and bottom phases and a crude load of 25% (w/w at pH 8.0. Recovery and recycling of components was also measured in each successive step process. The enzyme was successfully recovered by the proposed method with a high purification factor of 16.4 and yield of 97.4% while over 97% of the phase components were also recovered and recycled. This study demonstrated that the proposed novel aqueous two phase system method is more efficient and economical than the traditional aqueous two phase system method for the purification and recovery of the valuable enzyme lipase.

  11. A Novel Aqueous Two Phase System Composed of Surfactant and Xylitol for the Purification of Lipase from Pumpkin (Cucurbita moschata) Seeds and Recycling of Phase Components.

    Science.gov (United States)

    Amid, Mehrnoush; Manap, Mohd Yazid; Hussin, Muhaini; Mustafa, Shuhaimi

    2015-01-01

    Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was investigated. Moreover, the effect of system pH and crude load on the degree of purification and yield of the purified lipase were studied. The results indicated that the lipase was partitioned into the top surfactant rich phase while the impurities partitioned into the bottom xylitol-rich phase using an aqueous two phase system composed of 24% (w/w) Triton X-100 and 20% (w/w) xylitol, at 56.2% of tie line length (TLL), (TTL is one of the important parameters in this study and it is determined from a bimodal curve in which the tie-line connects two nodes on the bimodal, that represent concentration of phase components in the top and bottom phases) and a crude load of 25% (w/w) at pH 8.0. Recovery and recycling of components was also measured in each successive step process. The enzyme was successfully recovered by the proposed method with a high purification factor of 16.4 and yield of 97.4% while over 97% of the phase components were also recovered and recycled. This study demonstrated that the proposed novel aqueous two phase system method is more efficient and economical than the traditional aqueous two phase system method for the purification and recovery of the valuable enzyme lipase. PMID:26091076

  12. pH recycling aqueous two-phase systems applied in extraction of Maitake β-Glucan and mechanism analysis using low-field nuclear magnetic resonance.

    Science.gov (United States)

    Hou, Huiyun; Cao, Xuejun

    2015-07-31

    In this paper, a recycling aqueous two-phase systems (ATPS) based on two pH-response copolymers PADB and PMDM were used in purification of β-Glucan from Grifola frondosa. The main parameters, such as polymer concentration, type and concentration of salt, extraction temperature and pH, were investigated to optimize partition conditions. The results demonstrated that β-Glucan was extracted into PADB-rich phase, while impurities were extracted into PMDM-rich phase. In this 2.5% PADB/2.5% PMDM ATPS, 7.489 partition coefficient and 96.92% extraction recovery for β-Glucan were obtained in the presence of 30mmol/L KBr, at pH 8.20, 30°C. The phase-forming copolymers could be recycled by adjusting pH, with recoveries of over 96.0%. Furthermore, the partition mechanism of Maitake β-Glucan in PADB/PMDM aqueous two-phase systems was studied. Fourier transform infrared spectra, ForteBio Octet system and low-field nuclear magnetic resonance (LF-NMR) were introduced for elucidating the partition mechanism of β-Glucan. Especially, LF-NMR was firstly used in the mechanism analysis in partition of aqueous two-phase systems. The change of transverse relaxation time (T2) in ATPS could reflect the interaction between polymers and β-Glucan. PMID:26094138

  13. Design and development of single stage purification of papain using Ionic Liquid based aqueous two phase extraction system and its Partition coefficient studies

    Directory of Open Access Journals (Sweden)

    Senthilkumar Rathnasamy

    2013-04-01

    Full Text Available As an emerging trend in bioseparation, aqueous two phase extractions based on phosponium ionic liquid have been utilized in this work to extract papain from Carica papaya fruit latex and the same wascompared with conventional aqueous two phase extraction system. Factors affecting the partition coefficient of papain such as ionic liquid concentration, pH of the extraction system and temperature have been investigated. The optimization studies show that ionic liquid concentrations and pH are majorly influencing the phaseformations and papain partitioning. It reveals the importance of electrostatic and hydrophobic interactions in the papain partitioning. Purification studies performed on Gel Filtration Chromatography shows that 96% of the papain enzyme could be extracted with the phosponium based ionic liquid in a single stage extraction. The final fraction containing papain enzyme was confirmed by SDS Page analysis.

  14. Simultaneous separation/enrichment and detection of trace ciprofloxacin and lomefloxacin in food samples using thermosensitive smart polymers aqueous two-phase flotation system combined with HPLC.

    Science.gov (United States)

    Lu, Yang; Chen, Bo; Yu, Miao; Han, Juan; Wang, Yun; Tan, Zhenjiang; Yan, Yongsheng

    2016-11-01

    Smart polymer aqueous two phase flotation system (SPATPF) is a new separation and enrichment technology that integrated the advantages of the three technologies, i.e., aqueous two phase system, smart polymer and flotation sublation. Ethylene oxide and propylene oxide copolymer (EOPO)-(NH4)2SO4 SPATPF is a pretreatment technique, and it is coupled with high-performance liquid chromatography to analyze the trace ciprofloxacin and lomefloxacin in real food samples. The optimized conditions of experiment were determined in the multi-factor experiment by using response surface methodology. The flotation efficiency of lomefloxacin and ciprofloxacin was 94.50% and 98.23% under the optimized conditions. The recycling experimentsshowed that the smart polymer EOPO could use repeatedly, which will reduce the cost in the future application. PMID:27211613

  15. Design and evaluation of lornoxicam bilayered tablets for biphasic release

    Directory of Open Access Journals (Sweden)

    Songa Ambedkar Sunil

    2012-12-01

    Full Text Available The objective of the present investigation was to develop bilayered tablets of lornoxicam to achieve biphasic release pattern. A bilayered tablet, consisting of an immediate and controlled release layer, was prepared by direct compression technique. The controlled release effect was achieved by using various hydrophilic natural, semi synthetic and synthetic controlled release polymers such as xanthan gum, hydroxypropyl methylcellulose (HPMC and polyethylene oxide (PEO to modulate the release of the drug. The in vitro drug release profiles showed the biphasic release behavior in which the immediate release (IR layer containing the lornoxicam was released within 15 minutes, whereas the controlled release (CR layer controlled the drug release for up to 24 h. All the bilayered tablets formulated have followed the zero order release with non-Fickian diffusion controlled release mechanism after the initial burst release. FTIR studies revealed that there was no interaction between the drug and polymers used in the study. Statistical analysis (ANOVA showed no significant difference in the cumulative amount of drug release after 15 min, but significant difference (p O objetivo do presente trabalho foi desenvolver comprimidos bicamada de lornoxicam para atingir padrão de liberação bifásica. Preparou-se, por compressão direta, comprimido bicamada, consistindo de uma camada de liberação imediata e uma de liberação controlada. A liberação controlada foi obtida pelo uso de vários polímeros naturais hidrofílicos, semi-sintéticos e sintéticos, tais como goma xantana, hidroxipropilmetil celulose (HPMC e óxido de polietileno (PEO para modular a liberação do fármaco. Os perfis de liberação in vitro mostraram comportamento bifásico em que a camada de liberação imediata (IR contendo lornoxicam foi liberada em 15 minutos, enquanto a camada de liberação controlada (CR liberou o fármaco em mais de 24 horas, Todos os comprimidos bicamada

  16. Removal of xylenol orange from its aqueous solution using SDS self-microemulsifying systems: optimization by Box-Behnken statistical design.

    Science.gov (United States)

    Shakeel, Faiyaz; Haq, Nazrul; Alanazi, Fars K; Alsarra, Ibrahim A

    2014-04-01

    The aim of present study was to develop and evaluate sodium dodecyl sulfate (SDS) self-microemulsifying systems (SMES) for the removal of an anionic dye xylenol orange (XO) from its bulk aqueous media via liquid-liquid adsorption. The composition of SDS SMES was optimized by Box-Behnken statistical design for the maximum removal of XO from its aqueous solution. Various SDS formulations were prepared by spontaneous emulsification method and characterized for thermodynamic stability, self-microemulsification efficiency, droplet size, and viscosity. Adsorption studies were conducted at 8, 16, and 24 h by mixing small amounts of SDS formulations with relatively large amounts of bulk aqueous solution of XO. Droplet size and viscosity of SDS formulations were significantly influenced by oil phase concentration (triacetin), while surfactant concentration had little impact on droplet size and viscosity. However, the percentage of removal of XO was influenced by triacetin concentration, surfactant concentration, and adsorption time. Based on lowest droplet size (35.97 nm), lowest viscosity (29.62 cp), and highest percentage of removal efficiency (89.77 %), formulation F14, containing 2 % w/w of triacetin and 40 % w/w of surfactant mixture (20 % w/w of SDS and 20 % w/w of polyethylene glycol 400), was selected as an optimized formulation for the removal of XO from its bulk aqueous media after 16 h. These results indicated that SDS SMES could be suitable alternates of solid-liquid adsorption for the removal of toxic dyes such as XO from its aqueous solution through liquid-liquid adsorption. PMID:24390112

  17. Effects of aqueous extract of Hibiscus sabdariffa on the renin-angiotensin-aldosterone system of Nigerians with mild to moderate essential hypertension: A comparative study with lisinopril

    OpenAIRE

    Daniel Chukwu Nwachukwu; Eddy Ikemefuna Aneke; Leonard Fidelis Obika; Nkiru Zuada Nwachukwu

    2015-01-01

    Objectives: The present study investigated the effects of aqueous extract of Hibiscus sabdariffa (HS) on the three basic components of renin-angiotensin-aldosterone system: Plasma renin, serum angiotensin-converting enzyme (ACE), and plasma aldosterone (PA) in mild to moderate essential hypertensive Nigerians and compared with that of lisinopril, an ACE inhibitor. Materials and Methods: A double-blind controlled randomized clinical study was used. Seventy-eight newly diagnosed but untreate...

  18. A Novel Aqueous Two Phase System Composed of Surfactant and Xylitol for the Purification of Lipase from Pumpkin (Cucurbita moschata) Seeds and Recycling of Phase Components

    OpenAIRE

    Mehrnoush Amid; Mohd Yazid Manap; Muhaini Hussin; Shuhaimi Mustafa

    2015-01-01

    Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was invest...

  19. Extended UNIQUAC model for correlation and prediction of vapour-liquid-solid equilibria in aqueous salt systems containing non-electrolytes

    DEFF Research Database (Denmark)

    Iliuta, Maria C.; Thomsen, Kaj; Rasmussen, Peter

    2000-01-01

    The Extended UNIQUAC model has previously been used to describe the excess Gibbs energy for aqueous electrolyte mixtures. It is an electrolyte model formed by combining the original UNIQUAC model, the Debye-Huckel law and the Soave-Redlich-Kwong equation of state. In this work the model is extended...... the phase behaviour of methanol-water-three salts systems is illustrated. (C) 2000 Elsevier Science Ltd. All rights reserved....

  20. Structure and bonding nature of [PbCl]+ adsorption on the kaolinite(0 0 1) surface in aqueous system

    International Nuclear Information System (INIS)

    Highlights: • Adsorption of [PbCl]+ on the kaolinite(0 0 1) surface was first investigated by DFT. • A water environment was considered for species of [PbCl]+ and adsorption complex. • Binding energy was calculated based on the deprotonation of surface −OH group. • Complex structure, preferred adsorption position and adsorption type were solved. • Antibonding state filling was found involved in the Pb−O (or Cl) interaction. - Abstract: Adsorption of [PbCl]+ on the basal hydroxylated (0 0 1) surface of kaolinite in aqueous system was investigated by the plane-wave pseudopotential density functional theory calculations. Structures of the adsorption complexes including the coordination geometry and effective coordination number on the two different types of surface sites were examined, with the Pb−O (or Cl) bonding mechanism explored. [PbCl]+ prefers to bind with the hydroxylated kaolinite(0 0 1) surface in monodentate way on the site of Ou in “upright” hydroxyl. Complexation of [PbCl]+ in bidentate way on Ou−Ol (oxygen of “lying” hydroxyl) site of single Al center is also probable. All adsorption complexes feature coordination number of 3–5 within the hemidirected geometry. Charge transfer occurs with ligating atoms of oxygen denoting some electrons to Pb(II) and Cl. Upon the partial density of states (PDOS) projections and Mulliken bond populations, both bonding and antibonding state filling are involved in the Pb−O (or Cl) interaction. Pb 6p interacting with the antibonding combination of Pb 6s and O 2p states is the dominant orbital contribution of Pb(II) with surface oxygen, while the bonding Pb 6s−Cl 3p state filling is primarily responsible for the Pb−Cl interaction

  1. Neptunium oxide precipitation kinetics in aqueous systems at elevated temperatures. Part I: Colloidal, temperature, inert atmosphere, and ionic strength measurements

    International Nuclear Information System (INIS)

    We evaluate the proposed NpO2+(aq)-NpO2(cr) reduction-precipitation system at elevated temperatures to obtain primary information on the effects of temperature, ionic strength, O2 and CO2. Experiments conducted on unfiltered solutions at 10-4 M NpO2+(aq), neutral pH, and 200 C indicated that solution colloids strongly affect precipitation kinetics. Subsequent experiments on filtered solutions at 200, 212, and 225 C showed consistent and distinctive temperature-dependent behavior at reaction times (le) 800 hours. At longer times, the 200 C experiments showed unexpected dissolution of neptunium solids, but experiments at 212 C and 225 C demonstrated quasi steady-state neptunium concentrations of 3 x 10-6 M and 6 x 10-6 M, respectively. Solids from a representative experiment analyzed by X-ray diffraction were consistent with NpO2(cr). A 200 C experiment with a NaCl concentration of 0.05 M showed a dramatic increase in the rate of neptunium loss. A 200 C experiment in an argon atmosphere resulted in nearly complete loss of aqueous neptunium. Previously proposed NpO2+(aq)-NpO2(cr) reduction-precipitation mechanisms in the literature specified a 1:1 ratio of neptunium loss and H+ production in solution over time. However, all experiments demonstrated ratios of approximately 0.4 to 0.5. Carbonate equilibria can account for only about 40% of this discrepancy, leaving an unexpected deficit in H+ production that suggests that additional chemical processes are occurring.

  2. Flow of Aqueous Humor

    Science.gov (United States)

    ... Facebook Twitter Google Plus Email Print this page Flow of Aqueous Humor Most, but not all, forms ... aqueous humor) produced by the eye's ciliary body flows out freely (follow blue arrow). Aqueous humor flows ...

  3. Experimental validation of a new biphasic model of the contact mechanics of the porcine hip.

    Science.gov (United States)

    Li, Junyan; Wang, Qianqian; Jin, Zhongmin; Williams, Sophie; Fisher, John; Wilcox, Ruth K

    2014-05-30

    Hip models that incorporate the biphasic behaviour of articular cartilage can improve understanding of the joint function, pathology of joint degeneration and effect of potential interventions. The aim of this study was to develop a specimen-specific biphasic finite element model of a porcine acetabulum incorporating a biphasic representation of the articular cartilage and to validate the model predictions against direct experimental measurements of the contact area in the same specimen. Additionally, the effect of using a different tension-compression behaviour for the solid phase of the articular cartilage was investigated. The model represented different radial clearances and load magnitudes. The comparison of the finite element predictions and the experimental measurement showed good agreement in the location, size and shape of the contact area, and a similar trend in the relationship between contact area and load was observed. There was, however, a deviation of over 30% in the magnitude of the contact area, which might be due to experimental limitations or to simplifications in the material constitutive relationships used. In comparison with the isotropic solid phase model, the tension-compression solid phase model had better agreement with the experimental observations. The findings provide some confidence that the new biphasic methodology for modelling the cartilage is able to predict the contact mechanics of the hip joint. The validation provides a foundation for future subject-specific studies of the human hip using a biphasic cartilage model. PMID:24878736

  4. Purification of a fibrinolytic protease from Mucor subtilissimus UCP 1262 by aqueous two-phase systems (PEG/sulfate).

    Science.gov (United States)

    Nascimento, Thiago Pajeú; Sales, Amanda Emmanuelle; Porto, Camila Souza; Brandão, Romero Marcos Pedrosa; de Campos-Takaki, Galba Maria; Teixeira, José Antônio Couto; Porto, Tatiana Souza; Porto, Ana Lúcia Figueiredo; Converti, Attilio

    2016-07-01

    A fibrinolytic protease from M. subtilissimus UCP 1262 was recovered and partially purified by polyethylene glycol (PEG)/sodium sulfate aqueous two-phase systems (ATPS). The simultaneous influence of PEG molar mass, PEG concentration and sulfate concentration on the enzyme recovery was first investigated using a 2(3) full factorial design, and the Response Surface Methodology used to identify the optimum conditions for enzyme extraction by ATPS. Once the best PEG molar mass for the process had been selected (6000g/mol), a two-factor central composite rotary design was applied to better evaluate the effects of the other two independent variables. The fibrinolytic enzyme was shown to preferentially partition to the bottom phase with a partition coefficient (K) ranging from 0.2 to 0.7. The best results in terms of enzyme purification were obtained with the system formed by 30.0% (w/w) PEG 6000g/mol and 13.2% (w/w) sodium sulfate, which ensured a purification factor of 10.0, K of 0.2 and activity yield of 102.0%. SDS-PAGE and fibrin zymography showed that the purified protease has a molecular mass of 97kDa and an apparent isoelectric point of 5.4. When submitted to assays with different substrates and inhibitors, it showed selectivity for succinyl-l-ala-ala-pro-l-phenylalanine-p-nitroanilide and was almost completely inhibited by phenylmethylsulfonyl fluoride, behaving as a chymotrypsin-like protease. At the optimum temperature of 37°C, the enzyme residual activity was 94 and 68% of the initial one after 120 and 150min of incubation, respectively. This study demonstrated that M. subtilissimus protease has potent fibrinolytic activity compared with similar enzymes produced by solid-state fermentation, therefore it may be used as an agent for the prevention and therapy of thrombosis. Furthermore, it appears to have the advantages of low cost production and simple purification. PMID:27183214

  5. Henry’s constant of carbon dioxide-aqueous deep eutectic solvent (choline chloride/ethylene glycol, choline chloride/glycerol, choline chloride/malonic acid) systems

    International Nuclear Information System (INIS)

    Highlights: • A new set of Henry’s constant for the system carbon dioxide-aqueous deep eutectic solvents were measured. • The DESs used were: ethaline, glyceline, and maline. • The measured data were reported as functions of temperature and composition. • The measured data were represented satisfactorily by the applied correlations. -- Abstract: In this study, we present a new set of Henry’s constant data for the system carbon dioxide-aqueous deep eutectic solvent (DES) (20 to 80 wt% DES) at T = (303.15, 308.15, and 313.15) K. The DESs used were choline chloride-based: ethaline (choline chloride/ethylene glycol), glyceline (choline chloride/glycerol), and maline (choline chloride/malonic acid). A differential Henry’s coefficient model was used to describe the behaviour of Henry’s constant, and correlate it with temperature and concentration of DES in the aqueous DES solution. The correlation was found satisfactory such that the proposed model can be used in engineering calculations with reasonable accuracy

  6. A biphasic epigenetic switch controls immunoevasion, virulence and niche adaptation in non-typeable Haemophilus influenzae.

    Science.gov (United States)

    Atack, John M; Srikhanta, Yogitha N; Fox, Kate L; Jurcisek, Joseph A; Brockman, Kenneth L; Clark, Tyson A; Boitano, Matthew; Power, Peter M; Jen, Freda E-C; McEwan, Alastair G; Grimmond, Sean M; Smith, Arnold L; Barenkamp, Stephen J; Korlach, Jonas; Bakaletz, Lauren O; Jennings, Michael P

    2015-01-01

    Non-typeable Haemophilus influenzae contains an N(6)-adenine DNA-methyltransferase (ModA) that is subject to phase-variable expression (random ON/OFF switching). Five modA alleles, modA2, modA4, modA5, modA9 and modA10, account for over two-thirds of clinical otitis media isolates surveyed. Here, we use single molecule, real-time (SMRT) methylome analysis to identify the DNA-recognition motifs for all five of these modA alleles. Phase variation of these alleles regulates multiple proteins including vaccine candidates, and key virulence phenotypes such as antibiotic resistance (modA2, modA5, modA10), biofilm formation (modA2) and immunoevasion (modA4). Analyses of a modA2 strain in the chinchilla model of otitis media show a clear selection for ON switching of modA2 in the middle ear. Our results indicate that a biphasic epigenetic switch can control bacterial virulence, immunoevasion and niche adaptation in an animal model system. PMID:26215614

  7. Self-assembling multidomain peptides tailor biological responses through biphasic release.

    Science.gov (United States)

    Kumar, Vivek A; Taylor, Nichole L; Shi, Siyu; Wickremasinghe, Navindee C; D'Souza, Rena N; Hartgerink, Jeffrey D

    2015-06-01

    Delivery of small molecules and drugs to tissues is a mainstay of several tissue engineering strategies. Next generation treatments focused on localized drug delivery offer a more effective means in dealing with refractory healing when compared to systemic approaches. Here we describe a novel multidomain peptide hydrogel that capitalizes on synthetic peptide chemistry, supramolecular self-assembly and cytokine delivery to tailor biological responses. This material is biomimetic, shows shear stress recovery and offers a nanofibrous matrix that sequesters cytokines. The biphasic pattern of cytokine release results in the spatio-temporal activation of THP-1 monocytes and macrophages. Furthermore, macrophage-material interactions are promoted without generation of a proinflammatory environment. Subcutaneous implantation of injectable scaffolds showed a marked increase in macrophage infiltration and polarization dictated by cytokine loading as early as 3 days, with complete scaffold resorption by day 14. Macrophage interaction and response to the peptide composite facilitated the (i) recruitment of monocytes/macrophages, (ii) sustained residence of immune cells until degradation, and (iii) promotion of a pro-resolution M2 environment. Our results suggest the potential use of this injectable cytokine loaded hydrogel scaffold in a variety of tissue engineering applications. PMID:25818414

  8. Predictive score for early diagnosis of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD).

    Science.gov (United States)

    Tada, Hiroko; Takanashi, Jun-ichi; Okuno, Hideo; Kubota, Masaya; Yamagata, Takanori; Kawano, Gou; Shiihara, Takashi; Hamano, Shin-ichiro; Hirose, Shinichi; Hayashi, Takuya; Osaka, Hitoshi; Mizuguchi, Masashi

    2015-11-15

    Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) at onset manifests an early seizure (ES) usually lasting more than 30 min. Following ES, some patients exhibit almost clear consciousness with no neurological symptoms, and no MRI abnormality for a few days, which may lead to an initial misdiagnosis of prolonged febrile seizures (PFS). To allow an early diagnosis of AESD, we retrospectively analyzed clinical manifestations, laboratory data, and radiologic and EEG findings in patients with AESD (n=62) having ES of over 30 min, and ones with PFS (n=54), using logistic regression analyses. Multivariate logistic regression analysis revealed that an age below 1.5 years and a Glasgow Coma Scale score of 14 or less than 14 (Japan Coma Scale score of 1 or higher) were high risk factors of developing AESD. We proposed an AESD prediction score system consisting of consciousness level, age, duration of convulsions, enforcement of mechanical intubation, and aspartate aminotransferase, blood glucose and creatinine levels (full score: 9), the mean scores in AESD and PFS being 5.9 and 1.8, which were significantly different (psystem for differentiating patients with AESD and PFS around the time of ES (score of 4 or more than 4 suggesting AESD), which may contribute to early therapeutic intervention and an improved neurologic outcome. PMID:26333951

  9. Measurement and COrrelation on Viscosity and Apparent Molar Volume of Ternary System for L—ascorbic Acid in Aqueous D—Glucose and Sucrose Solutions

    Institute of Scientific and Technical Information of China (English)

    赵长伟; 马沛生

    2003-01-01

    Visosities and densities at ,several temperatures from 293.15 K to 313.15K are reported for L-ascorbic acid in aqueous glucose and sucrose solutions at different concentrations.The parameters of density,Viscosity coefficient B and partial molar volume are calculated by regression.The experimental results show that densities and viscositis decrease as temperature increases at the same solute and solvent (glucose and sucrose aueous solution)concentrations,and increase with concentration of glucose and sucrose at the same solute concentration and temperature,B increases with concentration of glucose and sucrose and temaperature,L-ascorbic acid is sturcture-breaker or structure-making for the glucose and sucrose aqueous solutions ,Furthermore,the solute-solvent interactions in ternary systems of water-glucose-electrolyte and water-sucrose-electrolyte are discussed.

  10. Three dimensional biphasic calcium phosphate nanocomposites for load bearing bioactive bone grafts.

    Science.gov (United States)

    Garai, Subhadra; Sinha, Arvind

    2016-02-01

    Mimicking matrix mediated bio-mineralization process, three dimensional blocks of biphasic calcium phosphate (BCP, hydroxyapatite (HA) and β-tricalcium phosphate (TCP)) nanocomposites, having three different stoichiometries have been synthesized for possible application as load bearing synthetic bone graft or scaffolds. Biphasic blocks with three weight ratios of 20:80, 25:75 and 30:70 of HA and TCP respectively have been synthesized. Detailed structural and chemical characterization of the samples revealed a strong dependence of porosity and mechanical properties on the stoichiometry of biphasic blocks. Effect of physiological medium on the microstructure and mechanical properties of the three different blocks has also been studied. Bioactivity of the BCP block, exhibiting highest compressive strength in air as well as in physiological medium, has been evaluated through adhesion, proliferation and differentiation of mesenchymal stem cells using different markers. PMID:26652386

  11. Bi-phasic Simulation of Metal Injection Moulding:Constitutive Determinations

    Institute of Scientific and Technical Information of China (English)

    Liu Baosheng(柳葆生); Barriere Thierry; Gelin Jean-Claude

    2003-01-01

    To predict the segregation effect in metal injection moulding (MIM) injection, a bi-phasic model based on mixture theory is adopted in simulation. An explicit algorithm is developed and realized by the authors, which conducts the simulation to be a cost-effective tool in MIM technology. In case of the bi-phasic simulation, the viscosity behaviours are necessary to be determined for the flows of each phase while only the viscosity of mixture is measurable by tests. It is a crucial problem for application of the bi-phasic simulation of MIM injection. A reasonable method is hence analysed and proposed to determine the viscosity behaviours of each phase. Even though this method may be furthermore modified in the future, it results in the practical simulation of segregation effects with reasonable parameters. The simulation results are compared with the measurements on injected specimens.

  12. A Structurally and Functionally Biomimetic Biphasic Scaffold for Intervertebral Disc Tissue Engineering.

    Directory of Open Access Journals (Sweden)

    Andrew Tsz Hang Choy

    Full Text Available Tissue engineering offers high hopes for the treatment of intervertebral disc (IVD degeneration. Whereas scaffolds of the disc nucleus and annulus have been extensively studied, a truly biomimetic and mechanically functional biphasic scaffold using naturally occurring extracellular matrix is yet to be developed. Here, a biphasic scaffold was fabricated with collagen and glycosaminoglycans (GAGs, two of the most abundant extracellular matrix components in the IVD. Following fabrication, the scaffold was characterized and benchmarked against native disc. The biphasic scaffold was composed of a collagen-GAG co-precipitate making up the nucleus pulposus-like core, and this was encapsulated in multiple lamellae of photochemically crosslinked collagen membranes comprising the annulus fibrosus-like lamellae. On mechanical testing, the height of our engineered disc recovered by ~82-89% in an annulus-independent manner, when compared with the 99% recovery exhibited by native disc. The annulus-independent nature of disc height recovery suggests that the fluid replacement function of the engineered nucleus pulposus core might mimic this hitherto unique feature of native disc. Biphasic scaffolds comprised of 10 annulus fibrosus-like lamellae had the best overall mechanical performance among the various designs owing to their similarity to native disc in most aspects, including elastic compliance during creep and recovery, and viscous compliance during recovery. However, the dynamic mechanical performance (including dynamic stiffness and damping factor of all the biphasic scaffolds was similar to that of the native discs. This study contributes to the rationalized design and development of a biomimetic and mechanically viable biphasic scaffold for IVD tissue engineering.

  13. (Liquid + liquid) equilibrium of the ternary aqueous system containing poly ethylene glycol dimethyl ether 2000 and tri-potassium citrate at different temperatures

    International Nuclear Information System (INIS)

    Highlights: ► LLE of (poly ethylene glycol dimethyl ether + tri potassium citrate + H2O) was studied. ► The effect of temperature on the binodals and tie-lines were investigated. ► Binodal data were correlated with two empirical equations. ► Tie-lines were fitted to several models including extended NRTL and modified NRTL. ► The entropy is driving force for aqueous two-phase formation. - Abstract: (Liquid + liquid) equilibria (LLE) of the {poly ethylene glycol di-methyl ether 2000 (PEGDME2000) + tri-potassium citrate + H2O} system have been determined experimentally at T = (298.15, 303.15, 308.15, and 318.15) K. The effect of temperature on the binodals and tie-lines for the investigated aqueous two-phase system (ATPS) has also been studied. In this work, the three fitting parameters of the Merchuk equation and an empirical equation that we proposed in our previous work were obtained with the temperature dependence expressed in the linear form with (T − T0) K as a variable. Furthermore, the Othmer–Tobias and Bancroft, a temperature dependent Setschenow-type equation and osmotic virial model, the segment-based local composition models (the extended NRTL and the modified NRTL) were used for the correlation and prediction of the liquid–liquid phase behavior of the system studied. In addition, the effect of the polymers PEGDME2000 and poly ethylene glycol 2000 on the phase forming ability were studied. Also, the free energies of cloud points for this system were calculated from which it was concluded that the increase of the entropy is driving force for formation of studied aqueous two-phase system.

  14. Volume fraction prediction in biphasic flow using nuclear technique and artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Cesar M.; Brandao, Luis E.B., E-mail: otero@ien.gov.br, E-mail: brandao@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The volume fraction is one of the most important parameters used to characterize air-liquid two-phase flows. It is a physical value to determine other parameters, such as the phase's densities and to determine the flow rate of each phase. These parameters are important to predict the flow pattern and to determine a mathematical model for the system. To study, for example, heat transfer and pressure drop. This work presents a methodology for volume fractions prediction in water-gas stratified flow regime using the nuclear technique and artificial intelligence. The volume fractions calculate in biphasic flow systems is complex and the analysis by means of analytical equations becomes very difficult. The approach is based on gamma-ray pulse height distributions pattern recognition by means of the artificial neural network. The detection system uses appropriate broad beam geometry, comprised of a ({sup 137}Cs) energy gamma-ray source and a NaI(Tl) scintillation detector in order measure transmitted beam whose the counts rates are influenced by the phases composition. These distributions are directly used by the network without any parameterization of the measured signal. The ideal and static theoretical models for stratified regime have been developed using MCNP-X code, which was used to provide training, test and validation data for the network. The detector also was modeled with this code and the results were compared to experimental photopeak efficiency measurements of radiation sources. The proposed network could obtain with satisfactory prediction of the volume fraction in water-gas system, demonstrating to be a promising approach for this purpose. (author)

  15. Volume fraction prediction in biphasic flow using nuclear technique and artificial neural network

    International Nuclear Information System (INIS)

    The volume fraction is one of the most important parameters used to characterize air-liquid two-phase flows. It is a physical value to determine other parameters, such as the phase's densities and to determine the flow rate of each phase. These parameters are important to predict the flow pattern and to determine a mathematical model for the system. To study, for example, heat transfer and pressure drop. This work presents a methodology for volume fractions prediction in water-gas stratified flow regime using the nuclear technique and artificial intelligence. The volume fractions calculate in biphasic flow systems is complex and the analysis by means of analytical equations becomes very difficult. The approach is based on gamma-ray pulse height distributions pattern recognition by means of the artificial neural network. The detection system uses appropriate broad beam geometry, comprised of a (137Cs) energy gamma-ray source and a NaI(Tl) scintillation detector in order measure transmitted beam whose the counts rates are influenced by the phases composition. These distributions are directly used by the network without any parameterization of the measured signal. The ideal and static theoretical models for stratified regime have been developed using MCNP-X code, which was used to provide training, test and validation data for the network. The detector also was modeled with this code and the results were compared to experimental photopeak efficiency measurements of radiation sources. The proposed network could obtain with satisfactory prediction of the volume fraction in water-gas system, demonstrating to be a promising approach for this purpose. (author)

  16. Phase equilibrium measurements for semi-clathrate hydrates of the (CO2 + N2 + tetra-n-butylammonium bromide) aqueous solution system

    International Nuclear Information System (INIS)

    Highlights: ► Semi-clathrate hydrate phase equilibrium for CO2+N2+TBAB aqueous solutions. ► Measurements for temperatures from 277.1 K to 293.2 K and pressures up to 16.21 MPa. ► TBAB has a promotion effect on semi-clathrate hydrate formation. - Abstract: The application of semi-clathrate hydrate formation technology for gas separation purposes has gained much attention in recent years. Consequently, there is a demand for experimental data for relevant semi-clathrate hydrate phase equilibria. In this work, semi-clathrate hydrate dissociation conditions for the system comprising mixtures of {CO2 (0.151/0.399 mole fraction) + N2 (0.849/0.601 mole fraction) + 0.05, 0.15, and 0.30 mass fraction tetra-n-butylammonium bromide (TBAB)} aqueous solutions have been measured and are reported. An experimental apparatus which was designed and built in-house was used for the measurements using the isochoric pressure-search method. The range of conditions for the measurements was from 277.1 K to 293.2 K for temperature and pressures up to 16.21 MPa. The phase equilibrium data measured demonstrate the high hydrate promotion effects of TBAB aqueous solutions.

  17. Is there an Optimal Shape of the Defibrillation Shock: Constant Current vs. Pulsed Biphasic Waveforms

    OpenAIRE

    Ivan Dotsinsky; Tsvetan Mudrov; Vessela Krasteva; Jecho Kostov

    2013-01-01

    Three waveforms for transthoracic defibrillation are assessed and compared: the Pulsed Biphasic Waveform (PBW), the Rectilinear Biphasic Waveform (RBW), and the "lossless" constant current (LLCC) pulses. Two indices are introduced: 1) kf = W/W0 - the ratio between the delivered energy W and the energy W0 of a rectangular pulse with the same duration and electric charge; 2) ηC = W/WC0 - the level of utilizing the initially loaded capacitor energy WC0. The envisioned comparative study shows tha...

  18. The standard biphasic-contrast examination of the stomach and duodenum

    International Nuclear Information System (INIS)

    A standard examination has been developed, called biphasic, because it combines the advantages of positive-contrast and double-contrast techniques. The theoretical background and technique of this examination are described and the basic interpretation of double-contrast studies stated. General remarks on the results and on the complementary role of radiological examination and endoscopy are included. A quantitative study of standard biphasic-contrast examinations in patients over a period of 3 years is presented. Finally a radiological atlas of common lesions of the stomach and duodenum is given. (C.F.)

  19. The biphasic virulence activities of gingipains: activation and inactivation of host proteins.

    Science.gov (United States)

    Imamura, Takahisa; Travis, James; Potempa, Jan

    2003-12-01

    Gingipains are trypsin-like cysteine proteinases produced by Porphyromonas gingivalis, a major causative bacterium of adult periodontitis. Rgps (HRgpA and RgpB) and Kgp are specific for -Arg-Xaa- and -Lys-Xaa- peptide bonds, respectively. HRgpA and Kgp are non-covalent complexes containing separate catalytic and adhesion/hemagglutinin domains, while RgpB has only a catalytic domain with a primary structure essentially identical to that of the cata-lytic subunit of HRgpA. The multiple virulence activities of gingipains are reviewed in view of the biphasic mechanisms: activation and inactivation of host proteins. Rgps enhanced vascular permeability through prekallikrein activation or direct bradykinin release in combination with Kgp. This Rgp action is potentially associated with gingival edema and crevicular fluid production. Rgps activate the blood coagulation system, leading to progression of inflammation and consequent alveolar bone loss in the periodontitis site. Rgps also activate protease-activated receptors and induce platelet aggregation, which, together with the coagulation-inducing activity, may explain an emerging link between periodontitis and cardiovascular disease. Kgp is the most potent fibrinogen/fibrin degrading enzyme of the three gingipains in human plasma, being involved in the bleeding tendency at the diseased gingiva. Gingipains stimulate expression of matrix metalloproteinases (MMPs) in fibroblasts and activate secreted latent MMPs that can destroy periodontal tissues. Gingipains degrade cytokines, components of the complement system and several receptors, including macrophage CD14, T cell CD4 and CD8, thus perturbing the host-defense systems and thereby facilitating sustained colonization of P. gingivalis. Gingipains are potent virulence factors of P. gingivalis, and in many regards their pathogenic activities constitute new mechanisms of bacterial virulence. PMID:14683429

  20. Surface modification of porous polycaprolactone/biphasic calcium phosphate scaffolds for bone regeneration in rat calvaria defect.

    Science.gov (United States)

    Kim, Ji-Hyun; Linh, Nguyen T B; Min, Young K; Lee, Byong-Taek

    2014-10-01

    In this study, polycaprolactone scaffolds fabricated by a salt-leaching process were loaded with biphasic calcium phosphate successfully to improve the osteoconductivity in bone regeneration. The surface of polycaprolactone/biphasic calcium phosphate scaffolds was aminolyzed by 1,6-hexamethylenediamine to introduce amino groups onto the surface, which was verified qualitatively by ninhyrin staining. Collagen was further immobilized on the aminolyzed porous polycaprolactone via N-ethyl-N'-(3-dimethylaminopropy) carbodiimide hydrochloride/hydroxy-2,5-dioxopyrolidine-3-sulfonic acid sodium cross-linking. The pore size of polycaprolactone/biphasic calcium phosphate-collagen scaffolds was 200-300 µm, which was suitable for bone in-growth. The X-ray photoelectron spectroscopy confirmed the coupling of collagen immobilized on the surface of polycaprolactone/biphasic calcium phosphate. In vitro results demonstrated that the spreading and viability of MC3T3-E1 cells were remarkably improved in the polycaprolactone/biphasic calcium phosphate-collagen scaffolds. The in vivo study was carried out by implanting the porous polycaprolactone, polycaprolactone/biphasic calcium phosphate, and polycaprolactone/biphasic calcium phosphate-collagen to the skulls of rats. Although the addition of biphasic calcium phosphate particles in the polycaprolactone scaffolds does not have a strong effect on the new bone formation, the immobilization of collagen on the polycaprolactone/biphasic calcium phosphate scaffolds significantly improved the bone regeneration even though the implantation time was short, 6 weeks. The present results provide more evidence that functionalizing polycaprolactone with biphasic calcium phosphate and collagen may be a feasible way to improve the osteoconduction in bone regeneration. PMID:24939961

  1. Aqueous deposition of calcium phosphates and silicate substituted calcium phosphates on magnesium alloys

    International Nuclear Information System (INIS)

    Attempts were made to deposit homogeneous films of calcium phosphates (CaPs) on two magnesium alloy systems, AZ31 and Mg–4Y, through an aqueous phosphating bath method. The deposition of silicate substituted CaPs by this aqueous method was also explored as silicate substitution is believed to increase the bioactivity of CaPs. The effect of doped and undoped coatings on the in vitro degradation and bioactivity of both alloy systems was studied. FTIR and EDX confirmed the deposition of Ca, P, and Si on both alloys and the coatings appeared to consist primarily biphasic mixtures of hydroxyapatite and β-TCP. These largely inhomogeneous coatings, as observed by SEM, were not shown to have any significant effect on maintaining the physiological pH of the culture medium in comparison to the uncoated samples, as the pH remained approximately in the 8.4–8.7 range. Interestingly, despite similar pH profiles between the coated and uncoated samples, CaP coatings affected the degradation of both alloys. These doped and undoped calcium phosphate coatings were observed to decrease the degradation of AZ31 whereas they increased the degradation of Mg–4Y. In vitro studies on cell attachment using MC3T3-E1 mouse osteoblasts showed that between the uncoated alloys, Mg–4Y appeared to be the more biocompatible of the two. Silicate substituted CaP coatings were observed to increase the cell attachment on AZ31 compared to bare and undoped CaPs coated samples, but did not have as great of an effect on increasing cell attachment on Mg–4Y.

  2. Direct 3D powder printing of biphasic calcium phosphate scaffolds for substitution of complex bone defects

    International Nuclear Information System (INIS)

    The 3D printing technique based on cement powders is an excellent method for the fabrication of individual and complex bone substitutes even in the case of large defects. The outstanding bone remodeling capacity of biphasic calcium phosphates (BCPs) containing hydroxyapatite (HA) as well as tricalcium phosphate (TCP) in varying ratios makes the adaption of powder systems resulting in BCP materials to this fabrication technique a desirable aim. This study presents the synthesis and characterization of a novel powder system for the 3D printing process, intended for the production of complexly shaped BCP scaffolds by a hydraulic setting reaction of calcium carbonate and TCP with phosphoric acid. The HA/TCP ratio in the specimens could be tailored by the calcium/phosphate ratio of the starting powder. The scaffolds could be fabricated with a dimensional accuracy of >96.5% and a minimal macro pore size of 300 µm. Independent of the phase composition the printed specimens showed a microporosity of approximately 68%, while the compressive strength strongly depended on the chemical composition and increased with rising TCP content in the scaffolds to a maximum of 1.81 MPa. Post-treatment of the scaffolds with a polylactic-co-glycolic acid-solution enhanced the mechanical properties by a factor of 8. In vitro studies showed that all BCP scaffolds were cytocompatible and enhanced the cell viability as well as the cell proliferation, as compared with pure TCP. Cell proliferation is even better on BCP when compared to HA and cell viability is in a similar range on these materials. (paper)

  3. Bio-Impedance Characterization Technique with Implantable Neural Stimulator Using Biphasic Current Stimulus

    Science.gov (United States)

    Lo, Yi-Kai; Chang, Chih-Wei; Liu, Wentai

    2016-01-01

    Knowledge of the bio-impedance and its equivalent circuit model at the electrode-electrolyte/tissue interface is important in the application of functional electrical stimulation. Impedance can be used as a merit to evaluate the proximity between electrodes and targeted tissues. Understanding the equivalent circuit parameters of the electrode can further be leveraged to set a safe boundary for stimulus parameters in order not to exceed the water window of electrodes. In this paper, we present an impedance characterization technique and implement a proof-of-concept system using an implantable neural stimulator and an off-the-shelf microcontroller. The proposed technique yields the parameters of the equivalent circuit of an electrode through large signal analysis by injecting a single low-intensity biphasic current stimulus with deliberately inserted inter-pulse delay and by acquiring the transient electrode voltage at three well-specified timings. Using low-intensity stimulus allows the derivation of electrode double layer capacitance since capacitive charge-injection dominates when electrode overpotential is small. Insertion of the inter-pulse delay creates a controlled discharge time to estimate the Faradic resistance. The proposed method has been validated by measuring the impedance of a) an emulated Randles cells made of discrete circuit components and b) a custom-made platinum electrode array in-vitro, and comparing estimated parameters with the results derived from an impedance analyzer. The proposed technique can be integrated into implantable or commercial neural stimulator system at low extra power consumption, low extra-hardware cost, and light computation. PMID:25569999

  4. Liquid-liquid equilibrium and partitioning features of bovine trypsin in Ucon 50 HB5100 /sodium citrate aqueous two phase systems

    OpenAIRE

    Tubío, Gisela; Venâncio, Armando; J. A. Teixeira; Nerli, Bibiana B.; Picó, Guillermo A.

    2008-01-01

    The phase diagrams of Ucon 50-HB-5100, a non-ionic random copolymer of ethylene oxide and propylene oxide (EOPO) and sodium citrate aqueous two-phase systems were determined at different pHs (5.20 and 8.20) and temperatures (5, 20 and 40º C). The binodal curves were determined by refractive index and enzymatic assay of the solution and described using a four-parameter sigmoidal equation, the reliability of the measured tie line compositions was ascertained by correlation equations...

  5. PREPARATION AND CHARACTERIZATION OF SOLID SELF MICROEMULSIFYING DRUG DELIVERY SYSTEM BY ADSORBENT TECHNIQUE TO IMPROVE DISSOLUTION PROFILE OF POORLY AQUEOUS SOLUBLE DRUG RAMIPRIL

    OpenAIRE

    Shelke Nagsen; Pancholi Shyam Sundar; Bandivadekar Mithun Mohanrao

    2011-01-01

    The main purpose of this work is to prepare solid self-microemulsifying drug delivery system (S-SMEDDS) to improve drug dissolution profile of poorly aqueous soluble drug. Optimized formulation of SMEDDS consists of Ramipril (RAM) (10 mg), Tween 80 (160mg), Cremophor EL (640mg) and Capmul MCM (CAP) as oil (200mg). SMEDDS was adsorbed at various SMEDDS: adsorbent ratio i.e. 3:1, 1:1, 1:3 on the solid carrier Aerosil 200. Powder flow properties and drug content were evaluated of the resulting f...

  6. Non-Aqueous Capillary Electrophoresis

    Science.gov (United States)

    Szumski, Michał; Buszewski, Bogusław

    Non-aqueous capillary electrophoresis and capillary electrochromatography are special variants of these techniques. Here, organic solvents or their mixtures with or without dissolved electrolytes are used as separation buffer or mobile phase, respectively. The most important features of non-aqueous systems are: better solubility of more hydrophobic ionic substances (many natural products) than in water, much less current and Joule heating allows for using highly concentrated buffers and/or larger capillary internal diameters, polar interactions are enhanced in organic solvents which is often highly advantageous in chiral separation systems. This chapter presents most frequently used solvents, their properties, as well as shows pH* scale which is often used in non-aqueous systems.

  7. Effect of biphase on dielectric properties of Bi-doped lead strontium titanate thin films

    International Nuclear Information System (INIS)

    Pb0.4Sr0.6TiO3 (PST) thin films doped with various concentration of Bi were prepared by a sol-gel method. The phase status, surface morphology and dielectric properties of these thin films were measured by X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance analyzer, respectively. Results showed that the thin films with the maximum dielectric constant and minimum dielectric loss were obtained for x=0.15. For x2Ti2O7 biphase were obtained. The thin films with pure Bi2Ti2O7 pyrochlore phase were obtained for x=0.67. The biphase thin films had high tunability and high figure of merit (FOM). The FOM of PST/Bi2Ti2O7 biphase thin film was about 6 times higher than that thin films formed with pure perovskite phase or pure pyrochlore phase. - Graphical abstract: The Bi-doped Pb0.4Sr0.6TiO3 (PST) thin films prepared by the sol-gel method showed a PST/Bi2Ti2O7 biphase structure for 0.2< x<0.4, and had the low dielectric capacitance and dielectric loss. Display Omitted

  8. Triple-channel microreactor for biphasic gas–liquid reactions: Photosensitized oxygenations

    Directory of Open Access Journals (Sweden)

    Ram Awatar Maurya

    2011-08-01

    Full Text Available A triple-channel microreactor fabricated by means of a soft-lithography technique was devised for efficient biphasic gas–liquid reactions. The excellent performance of the microreactor was demonstrated by carrying out photosensitized oxygenations of α-terpinene, citronellol, and allyl alcohols.

  9. Triple-channel microreactor for biphasic gas–liquid reactions: Photosensitized oxygenations

    OpenAIRE

    Ram Awatar Maurya; Chan Pil Park; Dong-Pyo Kim

    2011-01-01

    A triple-channel microreactor fabricated by means of a soft-lithography technique was devised for efficient biphasic gas–liquid reactions. The excellent performance of the microreactor was demonstrated by carrying out photosensitized oxygenations of α-terpinene, citronellol, and allyl alcohols.

  10. A New Type of Biphasic Calcium Phosphate Cement as a Gentamicin Carrier for Osteomyelitis

    Directory of Open Access Journals (Sweden)

    Wen-Yu Su

    2013-01-01

    Full Text Available Osteomyelitis therapy is a long-term and inconvenient procedure for a patient. Antibiotic-loaded bone cements are both a complementary and alternative treatment option to intravenous antibiotic therapy for the treatment of osteomyelitis. In the current study, the biphasic calcium phosphate cement (CPC, called α-TCP/HAP (α-tricalcium phosphate/hydroxyapatite biphasic cement, was prepared as an antibiotics carrier for osteomyelitis. The developed biphasic cement with a microstructure of α-TCP surrounding the HAP has a fast setting time which will fulfill the clinical demand. The X-ray diffraction and Fourier transform infrared spectrometry analyses showed the final phase to be HAP, the basic bone mineral, after setting for a period of time. Scanning electron microscopy revealed a porous structure with particle sizes of a few micrometers. The addition of gentamicin in α-TCP/HAP would delay the transition of α-TCP but would not change the final-phase HAP. The gentamicin-loaded α-TCP/HAP supplies high doses of the antibiotic during the initial 24 hours when they are soaked in phosphate buffer solution (PBS. Thereafter, a slower drug release is produced, supplying minimum inhibitory concentration until the end of the experiment (30 days. Studies of growth inhibition of Staphylococcus aureus and Pseudomonas aeruginosa in culture indicated that gentamicin released after 30 days from α-TCP/HAP biphasic cement retained antibacterial activity.

  11. Phase Behaviors in Bi-phase Simulation of Powder Segregation in Metal Injection Molding

    Institute of Scientific and Technical Information of China (English)

    Liu Baosheng; Fan Xiaoxin; Cheng Zhiqiang

    2006-01-01

    Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding (MIM). The prediction of segregation in MIM requires a bi-phase flow model to describe distinctly the flows of metallic powder and polymer binder. Viscous behaviors for the flows of each phase should hence be determined. The coefficient of interaction between the flows of two phases should also be evaluated. However, only viscosity of the mixed feedstock is measurable by capillary tests. Wall sticking is supposed in the traditional model for capillary tests, while the wall slip is important to be taken into account in MIM injection. Objective of the present paper is to introduce the slip effect in bi-phase simulation, and search the suitable way to determine the viscous behaviors for each phase with the consideration of wall slip in capillary tests. Analytical and numerical methods were proposed to realize such a specific purpose. The proposed method is based on the mass conservation between the capillary flows in mono-phase model for the mixed feedstock and in bi-phase model for the flows of two phases. Examples of the bi-phase simulation in MIM were realized with the software developed by research team. The results show evident segregation, which is valuable for improving the mould designs.

  12. Calculation of the valence electron structures of alloying cementite and its biphase interface

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The valence electron structures of alloying cementite θ-(Fe, M)3C and ε-(Fe, M)3C andthose of the biphase interfaces between them and α-Fe are calculated with Yu's empirical electrontheory of solid and molecules. The calculation results accord with the actual behavior of alloys.

  13. IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 3. Heavy Lanthanides (Gd–Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Mioduski, Tomasz [Institute of Nuclear Chemistry and Technology, 03195 Warszawa (Poland); Gumiński, Cezary, E-mail: cegie@chem.uw.edu.pl [Department of Chemistry, University of Warsaw, 02093 Warszawa (Poland); Zeng, Dewen, E-mail: dewen-zeng@hotmail.com [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

    2015-06-15

    This is the third part of the volume devoted to solubility data for the rare earth metal (REM) fluorides in water and in aqueous ternary and multicomponent systems. It covers experimental results of trivalent fluorides of Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu (so-called heavy lanthanides), since no quantitative data on solubilities of TbF{sub 4} and YbF{sub 2} (the most stable compounds at these valencies) are available. The related literature has been covered through the end of 2014. Compilations of all available papers with the solubility data are introduced for each REM fluoride with a corresponding critical evaluation. Every such assessment contains a collection of all solubility results in aqueous solution, a selection of suggested solubility data, a solubility equation, and a brief discussion of the multicomponent systems. Only simple fluorides (no complexes or double salts) are treated as the input substances in this report. General features of the systems, such as nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, solution pH, mixed solvent medium on the solubility, quality of the solubility results, and the solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

  14. Stereocomplex Film Using Triblock Copolymers of Polylactide and Poly(ethylene glycol) Retain Paxlitaxel on Substrates by an Aqueous Inkjet System.

    Science.gov (United States)

    Ajiro, Hiroharu; Kuroda, Ayaka; Kan, Kai; Akashi, Mitsuru

    2015-09-29

    The stereocomplex formation of poly(L,L-lactide) (PLLA) and poly(D,D-lactide) (PDLA) using an inkjet system was expanded to the amphiphilic copolymers, using poly(ethylene glycol) (PEG) as a hydrophilic polymer. The diblock copolymers, which are composed of PEG and PLLA (MPEG-co-PLLA) and PEG and PDLA (MPEG-co-PDLA), were employed for thin-film preparation using an aqueous inkjet system. The solvent and temperature conditions were optimized for the stereocomplex formation between MPEG-co-PLLA and MPEG-co- PDLA. As a result, the stereocomplex was adequately formed in acetonitrile/water (1:1, v/v) at 40 °C. The aqueous conditions improved the stereocomplex film preparation, which have suffered from clogging when using the organic solvents in previous work. The triblock copolymers, PLLA-co-PEG-co-PLLA and PDLA-co-PEG-co-PDLA, were employed for square patterning with the inkjet system, which produced thin films. The amphiphilic polymer film was able to retain hydrophobic compounds inside. The present result contributed to the rapid film preparation by inkjet, retaining drugs with difficult solubility in water, such as paclitaxel within the films. PMID:26343286

  15. PVDF-ErGO-GRC electrode: A single setup electrochemical system for separation, pre-concentration and detection of lead ions in complex aqueous samples.

    Science.gov (United States)

    Hamsawahini, Kunashegaran; Sathishkumar, Palanivel; Ahamad, Rahmalan; Yusoff, Abdull Rahim Mohd

    2016-02-01

    An effective electrode was developed based on electromembrane extraction (EME) and square wave voltammetry (SWV) for simultaneous separation, pre-concentration and determination of lead (II) (Pb(II)) ions in complex aqueous samples. Electrochemically reduced graphene oxide-graphite reinforced carbon (ErGO-GRC) was utilized in conjunction with the SWV. Pb(II) ions were extracted from an aqueous sample solution into an acidic acceptor phase (1M HCl) in the lumen of the polyvinylidene fluoride (PVDF) membrane bag by the application of voltage of maximum 6 V across the supported liquid membrane (SLM), consisting of organic solvent and di-(2-ethylhexyl)phosphoric acid (D2EHPA). The parameters affecting the EME were optimized for Pb(II) ions. The optimum EME conditions were found to be 20% D2EHPA in 1-octanol impregnated in the wall of PVDF membrane (PVDF17) as the SLM, extraction time of 20 min, pH of sample solution of 8 and a voltage of 5 V. The PVDF-ErGO-GRC electrode system attained enrichment factors of 40 times and 80% of extraction with relative standard deviations (n=5) of 8.3%. Good linearity ranging from 0.25 to 2 nM with coefficients correlation of 0.999 was obtained. The Pb(II) ions detection limit of PVDF-ErGO-GRC electrode was found to be 0.09 nM. The newly developed single setup electrochemical system was applied to complex aqueous samples such as tap, river and sea water to evaluate the feasibility of the method for applications. PMID:26653429

  16. Microbial degradation of the pharmaceutical ibuprofen and the herbicide 2,4-D in water and soil — Use and limits of data obtained from aqueous systems for predicting their fate in soil

    International Nuclear Information System (INIS)

    The persistence of chemicals is a key parameter for their environmental risk assessment. Extrapolating their biodegradability potential in aqueous systems to soil systems would improve the environmental impact assessment. This study compares the fate of 14/13C-labelled 2,4-D (2,4-dichlorophenoxyacetic acid) and ibuprofen in OECD tests 301 (ready biodegradability in aqueous systems) and 307 (soil). 85% of 2,4-D and 68% of ibuprofen were mineralised in aqueous systems, indicating ready biodegradability, but only 57% and 45% in soil. Parent compounds and metabolites decreased to < 2% of the spiked amounts in both systems. In soil, 36% of 2,4-D and 30% of ibuprofen were bound in non-extractable residues (NER). NER formation in the abiotic controls was half as high as in the biotic treatments. However, mineralisation, biodegradation and abiotic residue formation are competing processes. Assuming the same extent of abiotic NER formation in abiotic and biotic systems may therefore overestimate the abiotic contribution in the biotic systems. Mineralisation was described by a logistic model for the aquatic systems and by a two-pool first order degradation model for the soil systems. This agrees with the different abundance of microorganisms in the two systems, but precludes direct comparison of the fitted parameters. Nevertheless, the maximum mineralisable amounts determined by the models were similar in both systems, although the maximum mineralisation rate was about 3.5 times higher in the aqueous systems than in the soil system for both compounds; these parameters may thus be extrapolated from aqueous to soil systems. However, the maximum mineralisable amount is calculated by extrapolation to infinite times and includes intermediately formed biomass derived from the labelled carbon. The amount of labelled carbon within microbial biomass residues is higher in the soil system, resulting in lower degradation rates. Further evaluation of these relationships requires

  17. Microbial degradation of the pharmaceutical ibuprofen and the herbicide 2,4-D in water and soil — Use and limits of data obtained from aqueous systems for predicting their fate in soil

    Energy Technology Data Exchange (ETDEWEB)

    Girardi, Cristobal, E-mail: cristobal.girardi-lavin@ufz.de [UFZ — Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); Nowak, Karolina M. [UFZ — Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); Carranza-Diaz, Otoniel [UFZ — Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); UFZ — Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstraße 15, 04318 Leipzig (Germany); Lewkow, Benjamín [UFZ — Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); Miltner, Anja, E-mail: anja.miltner@ufz.de [UFZ — Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); Gehre, Matthias [UFZ — Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstraße 15, 04318 Leipzig (Germany); Schäffer, Andreas [Department of Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Kästner, Matthias [UFZ — Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany)

    2013-02-01

    The persistence of chemicals is a key parameter for their environmental risk assessment. Extrapolating their biodegradability potential in aqueous systems to soil systems would improve the environmental impact assessment. This study compares the fate of {sup 14/13}C-labelled 2,4-D (2,4-dichlorophenoxyacetic acid) and ibuprofen in OECD tests 301 (ready biodegradability in aqueous systems) and 307 (soil). 85% of 2,4-D and 68% of ibuprofen were mineralised in aqueous systems, indicating ready biodegradability, but only 57% and 45% in soil. Parent compounds and metabolites decreased to < 2% of the spiked amounts in both systems. In soil, 36% of 2,4-D and 30% of ibuprofen were bound in non-extractable residues (NER). NER formation in the abiotic controls was half as high as in the biotic treatments. However, mineralisation, biodegradation and abiotic residue formation are competing processes. Assuming the same extent of abiotic NER formation in abiotic and biotic systems may therefore overestimate the abiotic contribution in the biotic systems. Mineralisation was described by a logistic model for the aquatic systems and by a two-pool first order degradation model for the soil systems. This agrees with the different abundance of microorganisms in the two systems, but precludes direct comparison of the fitted parameters. Nevertheless, the maximum mineralisable amounts determined by the models were similar in both systems, although the maximum mineralisation rate was about 3.5 times higher in the aqueous systems than in the soil system for both compounds; these parameters may thus be extrapolated from aqueous to soil systems. However, the maximum mineralisable amount is calculated by extrapolation to infinite times and includes intermediately formed biomass derived from the labelled carbon. The amount of labelled carbon within microbial biomass residues is higher in the soil system, resulting in lower degradation rates. Further evaluation of these relationships requires

  18. Corrosion inhibition behavior of propyl phosphonic acid–Zn2+ system for carbon steel in aqueous solution

    International Nuclear Information System (INIS)

    The effectiveness of propyl phosphonic acid (PPA) as a corrosion inhibitor in association with a bivalent cation like Zn2+ has been studied. An eco-friendly inhibitor in controlling corrosion of carbon steel in neutral aqueous medium in the absence and presence of Zn2+ has been evaluated by gravimetric method. Impedance studies of the metal/solution interface indicated that the surface film is highly protective against the corrosion of carbon steel in the aqueous environment. Potentiodynamic polarization studies showed that the inhibitor is a mixed inhibitor. X-ray photoelectron spectroscopic analysis (XPS) of the protective film exhibited the presence of the elements viz., iron, phosphorus, oxygen, carbon and zinc. The chemical shifts in the binding energies of these elements inferred that the surface film is composed of oxides/hydroxides of iron(III), Zn(OH)2 and [Fe(II)/(III)–Zn(II)–PPA] complex. Further, the surface analysis techniques viz., FT-IR, AFM and SEM studies confirm the formation of an adsorbed protective film on the carbon steel surface. Based on all these results, a plausible mechanism of corrosion inhibition is proposed.

  19. IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 1. Introduction, Be and Mg

    Science.gov (United States)

    De Visscher, Alex; Vanderdeelen, Jan; Königsberger, Erich; Churagulov, Bulat R.; Ichikuni, Masami; Tsurumi, Makoto

    2012-03-01

    The alkaline earth carbonates are an important class of minerals. This volume compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1, the present paper, outlines the procedure adopted in this volume in detail, and presents the beryllium and magnesium carbonates. For the minerals magnesite (MgCO3), nesquehonite (MgCO3.3H2O), and lansfordite (MgCO3.5H2O), a critical evaluation is presented based on curve fits to empirical and/or thermodynamic models. Useful side products of the compilation and evaluation of the data outlined in the introduction are new relationships for the Henry constant of CO2 with Sechenov parameters, and for various equilibria in the aqueous phase including the dissociation constants of CO2(aq) and the stability constant of the ion pair MCO30(aq) (M = alkaline earth metal). Thermodynamic data of the alkaline earth carbonates consistent with two thermodynamic model variants are proposed. The model variant that describes the Mg2+-HCO3- ion interaction with Pitzer parameters was more consistent with the solubility data and with other thermodynamic data than the model variant that described the interaction with a stability constant.

  20. Organic aqueous tunable solvents (OATS): a vehicle for coupling reactions and separations.

    Science.gov (United States)

    Pollet, Pamela; Hart, Ryan J; Eckert, Charles A; Liotta, Charles L

    2010-09-21

    In laboratory-based chemical synthesis, the choice of the solvent and the means of product purification are rarely determined by cost or environmental impact considerations. When a reaction is scaled up for industrial applications, however, these choices are critical: the separation of product from the solvent, starting materials, and byproduct usually constitutes 60-80% of the overall cost of a process. In response, researchers have developed solvents and solvent-handling methods to optimize both the reaction and the subsequent separation steps on the manufacturing scale. These include "switchable" solvents, which are designed so that their physical properties can be changed abruptly, as well as "tunable" solvents, wherein the solvent's properties change continuously through the application of an external stimulus. In this Account, we describe the organic aqueous tunable solvent (OATS) system, examining two instructive and successful areas of application of OATS as well as its clear potential for further refinement. OATS systems address the limitations of biphasic processes by optimizing reactions and separations simultaneously. The reaction is performed homogeneously in a miscible aqueous-organic solvent mixture, such as water-tetrahydrofuran (THF). The efficient product separation is conducted heterogeneously by the simple addition of modest pressures of CO(2) (50-60 bar) to the system. Under these conditions, the water-THF phase splits into two relatively immiscible phases: the organic THF phase contains the hydrophobic product, and the aqueous phase contains the hydrophilic catalyst. We take advantage of the unique properties of OATS to develop environmentally benign and cost-competitive processes relevant in industrial applications. Specifically, we describe the use of OATS for optimizing the reaction, separation, design, and recycling of (i) Rh-catalyzed hydroformylation of olefins such as 1-octene and (ii) enzyme-catalyzed hydrolysis of 2-phenylacetate. We

  1. In situ patterning of organic molecules in aqueous solutions using an inverted electron-beam lithography system

    Science.gov (United States)

    Miyazako, Hiroki; Ishihara, Kazuhiko; Mabuchi, Kunihiko; Hoshino, Takayuki

    2016-06-01

    A method for in situ controlling the detachment and deposition of organic molecules such as sugars and biocompatible polymers in aqueous solutions by electron-beam (EB) scan is proposed and evaluated. It was demonstrated that EB irradiation could detach 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers from a silicon nitride membrane. Moreover, organic molecules such as cationic polymers and sugars could be deposited on the membrane by EB irradiation. Spatial distributions of scattered electrons were numerically simulated, and acceleration voltage dependences of the detachment and deposition phenomena were experimentally measured. The simulations and experimental results suggest that the detachment of MPC polymers is mainly due to electrical effects of primary electrons, and that the deposition of organic molecules is mainly due to chemical reactions induced by primary electrons. In view of these findings, the proposed method can be applied to in situ and nanoscale patterning such as the fabrication of cell scaffolds.

  2. Radiation sterilization of vitamins - studies on the radiolysis and radiation protection of vitamins in aqueous systems and the solid state

    International Nuclear Information System (INIS)

    Radiation sterilization of pharmaceutical products may cause their radiation degradation and loss in their potency. Radiation degradation may even give rise to new products whose effects on the organisms could be different from the parent substances. Extent of radiolytic decomposition of vitamins thiamine, nicotinamide, riboflavine and pyridoxine was studied under controlled conditions so that either only the hydrated electrons (esub(aq)) or only hydrogen atom (H) and hydroxyl radical react with these molecules. Experiments were also conducted in which scavengers for these species were added to reduce radiolytic degradation of the vitamins. It was found that irradiation of vitamins in the frozen aqueous state and with addition of glucose reduces radiolytic degradation and their irradiation in dry solid state causes no detectable damage. The last finding indicates that the best method for radiation sterilization of vitamin preparations may be to irradiate the components in the dry solid state and then compound them together. (M.G.B.)

  3. Compact optical cell system for vacuum ultraviolet absorption and circular dichroism spectroscopy and its application to aqueous solution sample.

    Science.gov (United States)

    Tanaka, Masahito; Yagi-Watanabe, Kazutoshi; Kaneko, Fusae; Nakagawa, Kazumichi

    2008-09-01

    We have designed a compact optical cell for studying the absorption and circular dichroism (CD) of a solution sample in the vacuum ultraviolet (VUV) region using a temperature control unit. The cell size was 34 mm in diameter and 14 mm in length. Such compactness was obtained by coating the VUV scintillator onto the outside of the back window. Because this scintillator converts the transmitted VUV light to visible light, the outside of this cell is operated under atmospheric pressure. The temperature of the sample solution was maintained in the range of 5 degrees C to 80 degrees C using a temperature control unit with a Peltier thermoelectric element. Changes in the sample temperature were observed by monitoring the absorption intensity of water. Through the study of VUV-CD spectra of ammonium camphor-10-sulfonate aqueous solutions and the transmitted spectrum of an empty cell, it was concluded that this cell unit has sufficient performance for use in VUV spectroscopy. PMID:18473342

  4. Transformation of Vesicles in Aqueous Two-Phase System of an Anionic Gemini Surfactant and a Cationic Conventional Surfactant Mixture

    Institute of Scientific and Technical Information of China (English)

    JIANG Rong; HUANG Yi-Xiong; ZHAO Jian-Xi; HUANG Chang-Cang

    2008-01-01

    Transformation of vesicles formed in DTAB/C11-p-PhCNa aqueous surfactant two-phase (ASTP) was observed by the transmission electron microscopy (TEM). The trans-conformation of the gemini surfactant in the aggregates was considered to be the important factor for constructing the multi-lamellar structure of the vesicle wall. The cation-π interaction between the quaternary ammonium cation and the aromatic ring in the spacer was determined by the UV-Vis spectrum analysis, which, as well as the general electrostatic attraction and hydrophobic force, contributes to the stability of the multi-lamellar structure. The concentrations of the surface-active ions were measured for understanding the mechanism of vesicle transformation. The results show that isoelectric mixing of the two components benefits the growth of vesicles both in size and wall thickness.

  5. Accumulation of zirconium phosphate by a Serratia sp.: a benign system for the removal of radionuclides from aqueous flows.

    Science.gov (United States)

    Mennan, Claire; Paterson-Beedle, Marion; Macaskie, Lynne E

    2010-10-01

    Metal phosphate deposited enzymatically on Serratia sp. has been used successfully for the removal of radionuclides from aqueous flows. Previous studies using biogenic hydrogen uranyl phosphate (HUP) on Serratia sp. biofilm showed removal of 100% of (90)Sr, (137)Cs, and (60)Co via their intercalation into biogenic HUP crystals. Zirconium phosphates (ZrP) offer a potential non-toxic and non-radioactive alternative to HUP for water decontamination. A method was developed for biomanufacturing ZrP. Biogenic ZrP removed ca. 100% of Sr(2+) and Co(2+) (0.5 mM) from solutions to a molar ratio at saturation of ca. 1:0.6 for both Zr:Sr and Zr:Co. The potential for drinking water decontamination via bio-ZrP is discussed with respect to bio-HUP and also other commercially available materials. PMID:20495949

  6. Studies of Several Systems with Air Electrode Electro-Synthesizing H2O2 on the Spot for Degrading Aniline in Aqueous

    Institute of Scientific and Technical Information of China (English)

    Cao Xiao-yu; Cai Nai-cai; Wang Yu-ling; Xie Ling-ling

    2003-01-01

    A gas diffusion electrode (air electrode) with a high current efficiency of electro-synthesizing H2O2 using O2 in air was prepared. The several systems with air electrode as cathode of electro-synthesizing H2 O2 on the reaction spot for degrading aniline in aqueous--electro-Fenton system, photo-excitation electro-H2 O2 system and photo-electro-Fenton system, were developed. The rates of decomposition of H2 O2 and mineralization of aniline were experimentally measured respectively under different conditions, and the results indicated there has an excellent parallel relation between decomposition rate of H2 O2 and mineralization rate of aniline. Especially, photo-electro-Fenton system, where H2 O2 is decomposed the fastest, is the best system of oxidizing and degrading organic toxicants. Compared photo-electro-Fenton system with photo-Fenton system, important role is revealed in the interface of air electrode. In this paper, the mineralization mechanism of aniline in the photo-electro-Fenton system was also discussed.

  7. Studies of Several Systems with Air Electrode Electro-Synthesizing H2O2 on the Spot for Degrading Aniline in Aqueous

    Institute of Scientific and Technical Information of China (English)

    Cao; Xiao-yu; Cai; Nai-cai; 等

    2003-01-01

    A gas diffusion electrode (air electrode) with a high current efficiency of electro-synthesizing H2O2 using O2 in air was prepared. The several systems with air electrode as cathode of electro-synthesizing H2O2 on the reaction spot for degrading aniline in aqueous--electro-Fenton system, photo-excitation electro-H2O2 system and photo-electro-Fenton system, were developed. The rates of decomposition of H2O2 and mineralization of aniline were experimentally measured respectively under different conditions, and the results indicated there has an excellent parallel relation between decomposition rate of H2O2 and mineralization rate of aniline. Especially, photo-electro-Fenton system, where H2O2 is decomposed the fastest, is the best system of oxidizing and degrading organic toxicants. Compared photo-electro-Fenton system with photo-Fenton system, important role is revealed in the interface of air electrode. In this paper, the mineralization mechanism of aniline in the photo-electro-Fenton system was also discussed.

  8. Interfacial Thermodynamics of Coexisting Aqueous Polymer Solutions

    NARCIS (Netherlands)

    Vis, M.

    2015-01-01

    Phase separation is commonly observed when two different polymers are present in aqueous solution, forming aqueous two-phase systems which typically consist for 90% of water. It is demonstrated that the presence of charge on one of the polymers results in an electric potential difference between the

  9. Equilibrium and kinetic studies for the biosorption system of copper(II) ion from aqueous solution using Tectona grandis L.f. leaves powder

    International Nuclear Information System (INIS)

    The biosorption of copper(II) ions from aqueous solution by Tectona grandis L.f. was studied in a batch adsorption system as a function of pH, metal ion concentration, adsorbent concentration and adsorbent size. The biosorption capacities and rates of copper(II) ions onto T. grandis L.f. were evaluated. The Langmuir, Freundlich, Redlich-Peterson and Temkin adsorption models were applied to describe the isotherms and isotherm constants. Biosorption isothermal data could be well interpreted by the Langmuir model with maximum adsorption capacity of 15.43 mg/g of copper(II) ion on T. grandis L.f. leaves powder. The kinetic experimental data properly correlated with the second-order kinetic model. Various thermodynamic parameters such as ΔGo, ΔHo, and ΔSo were calculated indicating that this system was a spontaneous and exothermic process

  10. AQUEOUS ROOT EXTRACT OF THE ANTIMALARIAL HERBAL CRYPTOLEPIS SANGUINOLENTA (LINDL. SCHLTR DELAYS THE DEVELOPMENT OF PHYSICAL LANDMARKS AND SENSORIMOTOR SYSTEMS IN MICE

    Directory of Open Access Journals (Sweden)

    K.B. Mensah and C. Ansah*

    2013-04-01

    Full Text Available ABSTRACT: We demonstrated previously that the aqueous root extract of Cryptolepis sanguinolenta (cryptolepis, with cryptolepine as the major constituent adversely affect reproduction and foetal development in mice. However, very little is known on the effect of prenatal exposure of cryptolepis on the post-natal life of surviving animals. Using murine models, we report here, the effects of prenatal exposure to cryptolepis on the growth and development of physical landmarks and sensorimotor systems. Prenatal cryptolepis (62.5, 100, 500 mg/kg; p.o treatment of pregnant mice from gestation day 6 - 19 significantly caused a delay in eye opening and development of reflexes such as righting, mid-air righting, auditory startle and pinna reflex. Prenatal cryptolepis treatment also inhibited intrauterine growth but not post-natal growth. This study shows that prenatal cryptolepis treatment provokes functional toxicity by delaying the development of physical landmarks and sensorimotor systems in mice.

  11. Studies of Redox Equilibria at Elevated Temperatures 2. An Automatic Divided-Function Autoclave and Cell with Flowing Liquid Junction for Electrochemical Measurements on Aqueous Systems

    International Nuclear Information System (INIS)

    An apparatus is described that has been developed for electrochemical studies of aqueous systems at temperatures above 100 deg C. It consists essentially of an electrically heated experimental cell enclosed by a separate pressure-vessel the walls of which are kept cool. This construction eliminates or reduces the problems of sealing electrical connections and of the corrosion of the pressure vessel, that commonly arise with conventional, externally-heated autoclaves. Pressure is applied to the cell by means of compressed air, diaphragm valves at the electrolyte outlet automatically maintaining the pressure in the cell about 1 atm lower than that in the pressure vessel. Two independent streams of electrolyte can be pumped into the experimental cell a special form of which has been developed in which may be formed a galvanic cell with a continuously regenerated flowing-liquid junction. In this form the apparatus enables experiments with, for example, one molal chloride solutions with pH 1-10, at temperatures up to about 250 deg C and under pressures up to about 40 atm. The apparatus has been tested in experiments in which classical measurements of the conductance of some aqueous electrolytes have been repeated. Good agreement with the earlier results has been obtained

  12. PREPARATION AND CHARACTERIZATION OF SOLID SELF MICROEMULSIFYING DRUG DELIVERY SYSTEM BY ADSORBENT TECHNIQUE TO IMPROVE DISSOLUTION PROFILE OF POORLY AQUEOUS SOLUBLE DRUG RAMIPRIL

    Directory of Open Access Journals (Sweden)

    Shelke Nagsen

    2011-06-01

    Full Text Available The main purpose of this work is to prepare solid self-microemulsifying drug delivery system (S-SMEDDS to improve drug dissolution profile of poorly aqueous soluble drug. Optimized formulation of SMEDDS consists of Ramipril (RAM (10 mg, Tween 80 (160mg, Cremophor EL (640mg and Capmul MCM (CAP as oil (200mg. SMEDDS was adsorbed at various SMEDDS: adsorbent ratio i.e. 3:1, 1:1, 1:3 on the solid carrier Aerosil 200. Powder flow properties and drug content were evaluated of the resulting formulations. The S-SMEDDS which showed maximum drug content in formulation & good flow properties were further evaluated & characterized for globule size, reconstitution properties, DSC, SEM & in-vitro dissolution profile. Converting liquid SMEDDS formulation to solid SMEDDS formulation is easy by adsorption on solid carrier technique. Formulation to Aerosil 200 ratio of 1:1 showed passable flow properties and high drug content. Also the reconstitution properties of the S-SMEDDS were not much altered. DSC study revealed that the drug was in solubilised form. SEM photographs showed that the formed particle were smooth and not much aggregation. Dissolution profile for Ramipril from S-SMEDDS was significantly higher than the conventional capsule. After three month stability study S-SMEDDS did not show any drug precipitation as well as phase separation. Our studies suggest that solid SMEDDS could be used as an effective oral solid dosage form to improve the dissolution profile of poorly aqueous soluble drug.

  13. Influence of pH, inorganic anions, and dissolved organic matter on the photolysis of antimicrobial triclocarban in aqueous systems under simulated sunlight irradiation.

    Science.gov (United States)

    Ding, Shi-Ling; Wang, Xi-Kui; Jiang, Wen-Qiang; Zhao, Ru-Song; Shen, Ting-Ting; Wang, Chen; Wang, Xia

    2015-04-01

    The photolysis of the antimicrobial triclocarban (TCC) in aqueous systems under simulated sunlight irradiation was studied. The effects of several abiotic parameters, including solution pH, initial TCC concentration, presence of natural organic matter, and most common inorganic anions in surface waters, were investigated. The results show that the photolysis of TCC followed pseudo-first-order kinetics. The TCC photolysis rate constant increased with increasing solution pH and decreasing the initial TCC concentration. Compared with the TCC photolysis in pure water, the presence of aqueous bicarbonate, nitrate, humic acids, and its sodium salt decreased the TCC photolysis rate, but fulvic acid increased the TCC photolysis rate. The electron spin resonance and reactive oxygen species scavenging experiments indicated that TCC may undergo two different types of phototransformation reactions: direct photolysis and energy transfer to generate (1)O2. The main degradation products were tentatively identified by gas chromatography interfaced with mass spectrometry (GC-MS), and a possible degradation pathway was also proposed. PMID:25354431

  14. Process for recovering pertechnetate ions from an aqueous solution also containing other ions

    Science.gov (United States)

    Rogers, R.; Horwitz, E.P.; Bond, A.H.

    1997-02-18

    A solid/liquid process for the separation and recovery of TcO{sub 4}{sup {minus}1} ions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups; whereas the aqueous solution from which the TcO{sub 4}{sup {minus}1} ions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt. A solid/liquid phase admixture of separation particles containing bound TcO{sub 4}{sup {minus}1} ions in such an aqueous solution that is free from MoO{sub 4}{sup {minus}2} ions is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture. 15 figs.

  15. Biphasic Insulin Aspart 30/70: Pharmacokinetics and Pharmacodynamics Compared With Once-Daily Biphasic Human Insulin and Basal-Bolus Therapy

    Science.gov (United States)

    Heise, Tim; Heinemann, Lutz; Hövelmann, Ulrike; Brauns, Bianca; Nosek, Leszek; Haahr, Hanne L.; Olsen, Klaus J.

    2009-01-01

    OBJECTIVE Pharmacological profiles of biphasic insulin aspart 30/70 (BIAsp 30) once daily (OD), twice daily (b.i.d.), and three times daily (t.i.d.) were compared with other insulin regimens in two crossover glucose clamp studies of insulin-treated type 2 diabetic patients. RESEARCH DESIGNS AND METHODS Study 1 consisted of BIAsp 30 OD, b.i.d., and t.i.d. versus biphasic human insulin 30/70 (BHI 30), OD (n = 24). Study 2 examined BIAsp 30 t.i.d. versus basal-bolus therapy (insulin glargine OD plus insulin glulisine t.i.d.) (n = 24). Pharmacokinetics/pharmacodynamics (PK/PD) were investigated over 24 h. RESULTS Study 1: PK and PD were markedly different between BIAsp 30 OD and BHI 30 OD: the maximum insulin concentration and glucose infusion rate (GIR) were higher for BIAsp 30; time to maximum metabolism was 1.7 h sooner for BIAsp 30. Study 2: both regimens showed three distinct prandial-related GIR peaks. GIR 24-h area under the curve for BIAsp t.i.d. was higher than for basal-bolus therapy: 2,585.2 vs. 2,289.2 mg/kg. CONCLUSIONS BIAsp had pharmacological advantages over BHI. BIAsp t.i.d. had a similar PD profile to basal-bolus therapy. PMID:19487640

  16. Efficacy and safety of biphasic insulin aspart and biphasic insulin lispro mix in patients with type 2 diabetes: A review of the literature.

    Science.gov (United States)

    Kumar, Ajay

    2016-01-01

    Type 2 diabetes (T2D) represents an escalating burden worldwide, particularly in China and India. Compared with Caucasians, Asian people with diabetes have lower body mass index, increased visceral adiposity, and postprandial glucose (PPG)/insulin resistance. Since postprandial hyperglycemia contributes significantly to total glycemic burden and is associated with heightened cardiovascular risk, targeting PPG early in T2D is paramount. Premixed insulin regimens are widely used in Asia due to their convenience and effectiveness. Data from randomized controlled trials and observational studies comparing efficacy and safety of biphasic insulin aspart 30 (BIAsp 30) with biphasic insulin lispro mix (LM 25/50) and versus other insulin therapies or oral antidiabetic drugs (OADs) in T2D demonstrated that BIAsp 30 and LM 25/50 were associated with similar or greater improvements in glycemic control versus comparator regimens, such as basal-bolus insulin, in insulin-naÏve, and prior insulin users. Studies directly comparing BIAsp 30 and LM 25 provided conflicting glycemic control results. Safety data generally showed increased hypoglycemia and weight gain with premixed insulins versus basal-bolus insulin or OADs. However, large observational trials documented improvements in glycated hemoglobin, PPG, and hypoglycemia with BIAsp 30 in multi-ethnic patient populations. In summary, this literature review demonstrates that premixed insulin regimens are an appropriate and effective treatment choice in T2D. PMID:27186543

  17. Efficacy and safety of biphasic insulin aspart and biphasic insulin lispro mix in patients with type 2 diabetes: A review of the literature

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2016-01-01

    Full Text Available Type 2 diabetes (T2D represents an escalating burden worldwide, particularly in China and India. Compared with Caucasians, Asian people with diabetes have lower body mass index, increased visceral adiposity, and postprandial glucose (PPG/insulin resistance. Since postprandial hyperglycemia contributes significantly to total glycemic burden and is associated with heightened cardiovascular risk, targeting PPG early in T2D is paramount. Premixed insulin regimens are widely used in Asia due to their convenience and effectiveness. Data from randomized controlled trials and observational studies comparing efficacy and safety of biphasic insulin aspart 30 (BIAsp 30 with biphasic insulin lispro mix (LM 25/50 and versus other insulin therapies or oral antidiabetic drugs (OADs in T2D demonstrated that BIAsp 30 and LM 25/50 were associated with similar or greater improvements in glycemic control versus comparator regimens, such as basal–bolus insulin, in insulin-naÏve, and prior insulin users. Studies directly comparing BIAsp 30 and LM 25 provided conflicting glycemic control results. Safety data generally showed increased hypoglycemia and weight gain with premixed insulins versus basal–bolus insulin or OADs. However, large observational trials documented improvements in glycated hemoglobin, PPG, and hypoglycemia with BIAsp 30 in multi-ethnic patient populations. In summary, this literature review demonstrates that premixed insulin regimens are an appropriate and effective treatment choice in T2D.

  18. Case Report: Multifocal biphasic squamoid alveolar renal cell carcinoma [version 1; referees: 2 approved, 1 approved with reservations

    OpenAIRE

    Jose Ignacio Lopez

    2016-01-01

    A multifocal biphasic squamoid alveolar renal cell carcinoma in a 68-year-old man is reported. Four different peripheral tumor nodules were identified on gross examination. A fifth central tumor corresponded to a conventional clear cell renal cell carcinoma. Biphasic squamoid alveolar renal cell carcinoma is a rare tumor that has been very recently characterized as a distinct histotype within the spectrum of papillary renal cell carcinoma. Immunostaining with cyclin D1 seems to be specific of...

  19. A biphasic finite element study on the role of the articular cartilage superficial zone in confined compression

    OpenAIRE

    Guo, Hongqiang; Maher, Suzanne A; Torzilli, Peter A.

    2014-01-01

    The aim of this study was to investigate the role of the superficial zone on the mechanical behavior of articular cartilage. Confined compression of articular cartilage was modeled using a biphasic finite element analysis to calculate the one-dimensional deformation of the extracellular matrix (ECM) and movement of the interstitial fluid through the ECM and articular surface. The articular cartilage was modeled as an inhomogeneous, nonlinear hyperelastic biphasic material with depth and strai...

  20. Production of dry Lactobacillus rhamnosus GG preparations by spray drying and lyophilization in aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    Katarzyna Leja

    2009-12-01

    Full Text Available Background. Drying is the oldest method of food preservation. It works by removing water from the food, which prevents the growth of microorganisms and decay. Moreover, spray or freeze drying is also used for the preservation of probiotic cultures. The aim of this study was to compare a survival rate of probiotic bacteria Lactobacillus rhamnosus during spray and freeze drying in ATPS. These results were also compared with survival rate of cells dried under the same conditions but suspended only in skim milk, 6% solution of PVP or 6% solution of dextran. Material and methods. The bacteria Lactobacillus rhamnosus GGwere suspended and spray or freeze dried in various types of aqueous two-phase emulsions: PVP/dextran, PEG4000/dextran and PEG8000/dextran. These emulsions consisted of different types of polymers and had varying ratio of polymers in dispersed (dextran and dispersing (PEG and PVP phases. Results. The research demonstrated that survival rate of bacteria directly after drying depended mainly on protective reagent, rather than on drying method. After 30-day-storage of the dried bacteria cell specimens, the highest survival rate was noted in case of freeze dried cells in milk. In case of spray drying the highest cell survival rate was observed when emulsion PVP3.6%/dextran2.4% was used as a drying medium. Conclusions. Finally, it has been found that cell survival rate was not strongly influenced by the storage temperature of the powder but it depended on the drying medium.  

  1. Phytoremediation potential of Myriophyllum aquaticum and Pistia stratiotes to modify antibiotic growth promoters, tetracycline, and oxytetracycline, in aqueous wastewater systems.

    Science.gov (United States)

    Gujarathi, Ninad P; Haney, Bryan J; Linden, James C

    2005-01-01

    Antibiotics are frequently used in the United States as feed efficiency promoters and medicines for livestock that is destined for human consumption. These antibiotics are released into the environment through the runoff and wastewater streams from animal feedlots and land applications of manure. The exposure of microorganisms to these antibiotics has reportedly resulted in the development of resistant species of microorganisms, which in turn can lead to human health hazards. Phytoremediation of these antibiotics can be a useful tool for countering this problem. Aquatic plants, Myriophyllum aquaticum (parrot feather) and Pistia stratiotes (water lettuce), were used for studying phytoremediation of tetracycline (TC) and oxytetracycline (OTC) from aqueous media. TC and OTC are two of the most commonly used tetracyclines in veterinary medicine. M. aquaticum and P. stratiotes gave high antibiotic modification rates of both antibiotics. Kinetic analyses dismiss direct enzyme catalysis; the modification rates decreased with increasing OTC concentrations. Sterile, cell-free root exudates (filtered through 0.2 microm membranes) from both species also exhibited comparable antibiotic modification rates. The involvement of root-secreted metabolites in antibiotic modification is suggested. The changes in the UV absorbance spectra of OTC during treatment with the root exudates confirmed the modification. PMID:16128442

  2. Removal of naphthalene from aqueous systems by poly(divinylbenzene) and poly(methyl methacrylate-divinylbenzene) resins.

    Science.gov (United States)

    da Silva, Carla M F; Rocha, Quéren da C; Rocha, Paulo Cristiano S; Louvisse, Ana Maria T; Lucas, Elizabete F

    2015-07-01

    Treatment of the oily wastewater from crude oil extraction is a growing challenge due to rising concern for the environment. Polyaromatic hydrocarbons (PAHs) deserve special attention because of their high toxicity. There is a need to develop processes able to minimize the discharge of these compounds and analytic techniques to monitor the levels of PAHs in aqueous media. In this study poly(methyl methacrylate-divinylbenzene) (MMA-DVB) and poly(divinylbenzene) (DVB) were assessed with respect to their capacity to retain naphthalene (NAF) in continuous flow and batch processes (adsorption equilibrium and kinetics). The analytic techniques applied were gas chromatography and spectrofluorimetry, which was adapted for quantification of NAF. The batch adsorption studies showed that DVB is more efficient in adsorption than MMA-DVB, and the Freundlich model and pseudo-second-order model better fitted the equilibrium data and adsorption kinetics, respectively. The elution results showed that both resins are highly efficient in removing NAF, with DVB outperforming MMA-DVB. However, MMA is cheaper raw material, making MMA-DVB more competitive for treatment of oily wastewater. The resins were regenerated by eluting about 7.2 and 2.5 L of methanol:water (70:30 v/v), respectively for DVB and MMA-DVB. Regarding to the useful life after regeneration, the resins presented a reduction about 30%, relating to zero concentration of NAF. PMID:25910974

  3. Role of Citrate Ions in the Phosphonate-based Inhibitor System for Mild Steel in Aqueous Chloride Media

    Directory of Open Access Journals (Sweden)

    G. Gunasekaran

    2005-01-01

    Full Text Available The corrosion inhibition efficiency of phosphonic acid and its derivatives for the inhibition of corrosion of mild steel in neutral chloride media is decided by its ability to form protectivefilm over the surface. In this context, the effect of addition of metal cations and certain organic compounds, such as citrate in conjugation with phosphonic acid to impart synergistic corrosion inhibition has been explored. The experiments were carried out using various concentrations of trisodium citrate and zinc ions in an aqueous solution of 2-carboxyethyl phosphonic acid (2CEPA at 25 ppm. The corrosion characteristics have been determined using electrochemical impedance spectroscopy together with determination of corrosion rate by weight-loss method. It has been observed that a combination of inhibitive ions, namely citrate, ZCEPA, and zinc ions at 25 ppm gives 96 per cent inhibition efficiency and this corrosion inhibition is due to the formation of a protective film. By increasing the concentration of citrate beyond 25 ppm, the corrosion inhibition efficiency decreases. This paper discusses the role of citrate and zinc ions in imparting added corrosion inhibition ability using 2CEPA on the basis of experimental results.

  4. Ultra-rapid growth of biphasic nanowires in micro- and hypergravity.

    Science.gov (United States)

    Veith, Michael; Lee, Juseok; Schmid, Herbert; Aktas, Cenk

    2013-04-01

    Aluminium/aluminium oxide wires form under microgravity, earth conditions, and hypergravity in different forms. While under 0.04 G the biphasic wires are predominantly linear, they form bundles of wires of high curvature at 1 G and 1.8 G. The absence (0.04 G) and presence (1 G, 1.8 G) of gradients are reflected by the agglomeration and growth direction of the nanowires. PMID:23239577

  5. Biphasic parapharyngeal synovial sarcoma: a cytologic and immunocytologic report of a case

    OpenAIRE

    Mohammadianpanah Mohammad; Daneshbod Yahya; Negahban Shahrzad; Daneshbod Khosrow; Ashraf Mohammad; Khademi Bijan; Kaviani Massud

    2006-01-01

    Abstract Background Synovial sarcoma is a rare soft tissue sarcoma in the head and neck region and parapharyngeal space. There is no previous cytologic report of synovial sarcoma of parapharynx. The cytologic and immunocytochemical findings of a parapharyngeal biphasic synovial sarcoma together with diagnostic pitfalls are described. Case report A 21-year-old girl presented with a 6-month history of progressive right arm pain, neck mass and upper aerodigestive tract obstruction. On physical e...

  6. Primary pulmonary sarcoma with morphologic features of biphasic synovial sarcoma: a case report.

    OpenAIRE

    Yoon, G. S.; Park, S Y; Kang, G. H.; Kim, O. J.

    1998-01-01

    We report an unusual primary case of pulmonary sarcoma that developed in the lung of a 36-year-old woman. The tumor had histologic, immunologic and ultrastructural features identical to those of biphasic synovial sarcoma of the soft tissue. It consisted of an intimate admixture of cytokeratin and epithelial membrane antigen(EMA)-positive neoplastic epithelial cells and vimentin-positive fibroblast-like spindle cells with areas of hyalinization. The patient had a lobectomy and showed no eviden...

  7. Changes in biphasic electrode impedance with protein adsorption and cell growth

    OpenAIRE

    Newbold, Carrie; Richardson, Rachael; Millard, Rodney; Huang, Christie; Milojevic, Dusan; Shepherd, Robert; Cowan, Robert

    2010-01-01

    This study was undertaken to assess the contribution of protein adsorption and cell growth to increases in electrode impedance that occur immediately following implantation of cochlear implant electrodes and other neural stimulation devices. An in vitro model of the electrode-tissue interface was used. Radiolabelled albumin in phosphate buffered saline was added to planar gold electrodes and electrode impedance measured using a charge-balanced biphasic current pulse. The polarisation impedanc...

  8. Localized biphasic type malignant mesothelioma arising in the peritoneum: Report of a case

    OpenAIRE

    Kohno, Mikihiro; Maruyama, Riichiroh; Kitagawa, Dai; Sugimachi, Keishi; Kinjo, Mitsuru; Higashi, Hidefumi

    2014-01-01

    This report describes a rare case of localized malignant biphasic (mixed epithelioid and sarcomatoid) mesothelioma arising in the peritoneum. A 69-year-old male with a history of asbestos exposure, complaining of a painful mass in the left chest wall, was found via computed tomography (CT) to have a tumor in the left peritoneum. The resected tumor was histologically and immunohistochemically consistent with a malignant mesothelioma with mixed epithelioid and sarcomatoid type and no distant me...

  9. A biphase shift keying (BPSK), direct sequence, spread spectrum modem for Petite Amateur Navy Satellite (PANSAT).

    OpenAIRE

    Fritz, Thomas M.

    1992-01-01

    Approved for public release; distribution is unlimited The development of a bi-phase shift keying (BPSK), direct sequence, spread spectrum modem is conducted for the purpose of creating a prototype design to be implemented in the Petite Amateur Navy Satellite (PANSAT). The design discussion includes the hardware used in the functional realization of a working design. The design itself encompasses selection of components and demonstrates (through circuit diagrams and waveform...

  10. A simulation study of the reaction of human heart to biphasic electrical shocks

    Directory of Open Access Journals (Sweden)

    Seemann Gunnar

    2004-06-01

    Full Text Available Abstract Background This article presents a study, which examines the effects of biphasic electrical shocks on human ventricular tissue. The effects of this type of shock are not yet fully understood. Animal experiments showed the superiority of biphasic shocks over monophasic ones in defibrillation. A mathematical computer simulation can increase the knowledge of human heart behavior. Methods The research presented in this article was done with different models representing a three-dimensional wedge of ventricular myocardium. The electrophysiology was described with Priebe-Beuckelmann model. The realistic fiber twist, which is specific to human myocardium was included. Planar electrodes were placed at the ends of the longest side of the virtual cardiac wedge, in a bath medium. They were sources of electrical shocks, which varied in magnitude from 0.1 to 5 V. In a second arrangement ring electrodes were placed directly on myocardium for getting a better view on secondary electrical sources. The electrical reaction of the tissue was generated with a bidomain model. Results The reaction of the tissue to the electrical shock was specific to the initial imposed characteristics. Depolarization appeared in the first 5 ms in different locations. A further study of the cardiac tissue behavior revealed, which features influence the response of the considered muscle. It was shown that the time needed by the tissue to be totally depolarized is much shorter when a biphasic shock is applied. Each simulation ended only after complete repolarization was achieved. This created the possibility of gathering information from all states corresponding to one cycle of the cardiac rhythm. Conclusions The differences between the reaction of the homogeneous tissue and a tissue, which contains cleavage planes, reveals important aspects of superiority of biphasic pulses. ...

  11. Development of bioprocesses based in biphasic media involving the yeast Yarrowia lipolytica

    OpenAIRE

    Gomes, N.; Gonçalves, C; Lopes, M.; Aguedo, Mario; Teixeira, J. A.; M. Mota; Belo, I.

    2008-01-01

    Yarrowia lipolytica has been intensively used in our research group to develop different bioprocesses based in the ability of this yeast to use hydrophobic substrates. Work has been focused in the optimization of the production of y-decalactone and lipase, and to degrade and detoxify olive oil wastewater producing simultaneously high-value compounds, such as enzymes. Studies of the oxygen mass transfer phenomenon in biphasic media was also conducted and applied to select the mo...

  12. Biodiesel production from crude jatropha oil catalyzed by immobilized lipase/acyltransferase from Candida parapsilosis in aqueous medium.

    Science.gov (United States)

    Rodrigues, Joana; Perrier, Véronique; Lecomte, Jérôme; Dubreucq, Eric; Ferreira-Dias, Suzana

    2016-10-01

    The lipase/acyltransferase from Candida parapsilosis (CpLIP2) immobilized on two synthetic resins (Accurel MP 1000 and Lewatit VP OC 1600) was used as catalyst for the production of biodiesel (fatty acid methyl esters, FAME) by transesterification of jatropha oil with methanol, in a lipid/aqueous system. The oil was dispersed in a buffer solution (pH 6.5) containing methanol in excess (2M in the biphasic system; molar ratio methanol/acyl chains 2:1). Transesterification was carried out at 30°C, under magnetic stirring, using 10% (w/w) of immobilized enzyme in relation to oil. The maximum FAME yields were attained after 8h reaction time: 80.5% and 93.8%, when CpLIP2 immobilized on Accurel MP 1000 or on Lewatit VP OC 1600 were used, respectively. CpLIP2 on both Accurel MP 1000 and Lewatit VP OC 1600 showed high operational stability along 5 consecutive 8h batches. PMID:27474957

  13. Modeling and design of reacting systems with phase transfer catalysis

    DEFF Research Database (Denmark)

    Piccolo, Chiara; Hodges, George; Piccione, Patrick M.;

    2011-01-01

    systems. A model-based strategy for the selection of the best organic solvent/catalyst that improves the reaction operation is highlighted for the reacting system: benzyl chloride (A) and sodium bromide (B) reacting through tetrabutylammonium bromide (PTC).......Issues related to the design of biphasic (liquid) catalytic reaction operations are discussed. A chemical system involving the reaction of an organic-phase soluble reactant (A) with an aqueous-phase soluble reactant (B) in the presence of phase transfer catalyst (PTC) is modeled and based on it......, some of the design issues related to improved reaction operation are analyzed. Since the solubility of the different forms of the PTC in the organic solvent affects ultimately the catalyst partition coefficients, therefore, the organic solvent plays an important role in the design of PTC-based reacting...

  14. Radiation yields of phenol derivatives in nitrobenzene-water systems

    International Nuclear Information System (INIS)

    Radiolysis of nitrobenzene was studied in two-phase systems with water, sulfuric acid and nitric acid solutions. In kinetic regime of radiolysis the two-phase additivity rule was applied to calculate partial radiation yields of p-nitrophenol, m-nitrophenol, p-nitrosophenol, 2,4-dinitrophenol, 2,5-dinitrophenol, o-nitroaniline and o-, m-, p-aminophenols in the systems of various volume ratios. Nitrobenzene phase was found to be several times more reactive than the aqueous one in respect of the phenols and aniline derivatives formation. In the absence of agitation the yields depend strongly on the thickness of the phases irradiated, as it ensues from the diffusion regime theory of radiolysis in biphasic systems, which was illustrated. (author)

  15. Synchronized oscillations of dimers in biphasic charged fd-virus suspensions

    Science.gov (United States)

    Kang, K.; Piao, S. H.; Choi, H. J.

    2016-08-01

    Micron-sized colloidal spheres that are dispersed in an isotropic-nematic biphasic host suspension of charged rods (fd-virus particles) are shown to spontaneously form dimers, which exhibit a synchronized oscillatory motion. Dimer formation is not observed in the monophase of isotropic and nematic suspensions. The synchronized oscillations of dimers are connected to the inhomogeneous state of the host suspension of charged rods (fd viruses) where nematic domains are in coexistence with isotropic regions. The synchronization of oscillations occurs in bulk states, in the absence of an external field. With a low field strength of an applied electric field, the synchronization is rather reduced, but it recovers again when the field is turned off. In this Rapid Communication, we report this observation as an example of the strange attractor, occurring in the mixture of PS (polystyrene) dimers in an isotropic-nematic coexistence biphasic fd-virus network. Furthermore, we highlight that the synchronization of PS-dimer oscillations is the result of a global bifurcation diagram, driven by a delicate balance between the short-attractive "twisted" interaction of PS dimers and long-ranged electrostatic repulsive interactions of charged fd rods. The interest is then in the local enhancement of "twist-nematic" elasticity in reorientation of the dimer oscillations. An analysis of image-time correlations is provided with the data movies and Fourier transforms of averaged orientations for the synchronized oscillations of dimers in the biphasic I -N coexistence concentration of charged fd-virus suspensions.

  16. Two-photon-excited fluorescence resonance energy transfer in an aqueous system of CdTe quantum dots and Rhodamine B

    International Nuclear Information System (INIS)

    Two-photon excited fluorescence resonance energy transfer (FRET) between CdTe quantum dots with different emission peaks and Rhodamine B in aqueous solution are investigated both experimentally and theoretically. The photoluminescence and lifetime are measured using a time-resolved fluorescence test system. The two-photon excited FRET efficiency is found to increase as the degree of spectral overlap of the emission spectrum of CdTe and the absorption spectrum of Rhodamine B increases, which is due to the increase of Forster radius of the sample. Moreover, FRET efficiency increases when the ratio of acceptor/donor concentration increases. The two-photon excited FRET efficiency was found to reach 40%

  17. Calculation of liquid-liquid equilibrium of aqueous two-phase systems using a chemical-theory-based excess Gibbs energy model

    Directory of Open Access Journals (Sweden)

    Pessôa Filho P. A.

    2004-01-01

    Full Text Available Mixtures containing compounds that undergo hydrogen bonding show large deviations from ideal behavior. These deviations can be accounted for through chemical theory, according to which the formation of a hydrogen bond can be treated as a chemical reaction. This chemical equilibrium needs to be taken into account when applying stability criteria and carrying out phase equilibrium calculations. In this work, we illustrate the application of the stability criteria to establish the conditions under which a liquid-phase split may occur and the subsequent calculation of liquid-liquid equilibrium using a chemical-theory-modified Flory-Huggins equation to describe the non ideality of aqueous two-phase systems composed of poly(ethylene glycol and dextran. The model was found to be able to correlate ternary liquid-liquid diagrams reasonably well by simple adjustment of the polymer-polymer binary interaction parameter.

  18. Thin-layer chromatography of 49 metal ions on stannic antimonate in aqueous and mixed solvent systems containing dimethylsulfoxide: quantitative separation of uranium from numerous metal ions

    International Nuclear Information System (INIS)

    Thin-layer chromatography of 40 metal ions in 31 aqueous and mixed solvent systems has been performed on stannic antimonate ion-exchange material. Dimethylsulfoxide has been utilized to resolve such binary mixtures as La3+ and Ce3+ from Pr3+, Nd3+, and Sm3+; VO2+ from Ti4+, Nb5+, and Ta5+; Ga3+ from In3+, Tl+, and Y3+; Fe3+ from VO2+; and Mg2+ from Al3+. Quantitative separation of 200 to 800 μg U from its binary mixtures and from the synthetic mixtures containing Mg2+, Bi3+, Fe3+, Th4+, Ce4+, Cr3+, Zr4+, Hf4+, Ti4+ Mn2+, Cu2+, Ce3+, In3+, Y3+, Ca2+, Co2+, Tl+, Nb5+, and Ag+ has been obtained

  19. Phase transfer of platinum nanoparticles from aqueous to organic solutions using fatty amine molecules

    Indian Academy of Sciences (India)

    Ashavani Kumar; Hrushikesh M Joshi; Anandrao B Mandale; Rajendra Srivastava; Suguna D Adyanthaya; Renu Pasricha; Murali Sastry

    2004-08-01

    In this report we demonstrate a simple process based on amine chemistry for the phase transfer of platinum nanoparticles from an aqueous to an organic solution. The phase transfer was accomplished by vigorous shaking of a biphasic mixture of platinum nanoparticles synthesised in an aqueous medium and octadecylamine (ODA) in hexane. During shaking of the biphasic mixture, the aqueous platinum nanoparticles complex via either coordination bond formation or weak covalent interaction with the ODA molecules present in the organic phase. This process renders the nanoparticles sufficiently hydrophobic and dispersible in the organic phase. The ODA-stabilised platinum nanoparticles could be separated out from hexane in the form of a powder that is readily redispersible in weakly polar and nonpolar organic solvents. The ODA-capped platinum nanoparticles show high catalytic activity in hydrogenation reactions and this is demonstrated in the efficient conversion of styrene to ethyl benzene. The nature of binding of the ODA molecules to the platinum nanoparticles surface was characterised by thermogravimetry, transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR).

  20. EFFECT OF ALCOHOL ON AQUEOUS TWO-PHASE SYSTEM PROPERTIES OF SDS/CTAB/H2O/Na2SO4 SYSTEM%醇对正负离子表面活性剂双水相性质的影响

    Institute of Scientific and Technical Information of China (English)

    滕弘霓; 王利

    2004-01-01

    The effect of alcohol on the aqueous two-phase system properties of SDS/CTAB/H2O/Na2SO4 system was studied by the pseudo ternary phase diagram. The electrostatic forces (both attraction and repulsion) between cationic surfactant and anionic surfactant decreased because of the interaction of alcohol hydroxyl group and surfactant polar group. As a result, the phase area width of aqueous two-phase system increased. Long chain alcohol (more than five carbonatoms), which was in high concentration in the SDS/CTAB/H2O/Na2SO4) system, caused the anionic aqueous two-phase system area to vanish and the cationic aqueous two-phase system area to become wider. The CTAB rich phase turned from top phase to bottom phase.

  1. Recent results of the investigation of a micro-fluidic sampling chip and sampling system for hot cell aqueous processing streams

    International Nuclear Information System (INIS)

    A Fuel Cycle Research and Development project has investigated an innovative sampling method that could evolve into the next generation sampling and analysis system for metallic elements present in aqueous processing streams. Initially sampling technologies were evaluated and micro-fluidic sampling chip technology was selected and tested. A conceptual design for a fully automated microcapillary-based system was completed and a robotic automated sampling system was fabricated. The mechanical and sampling operation of the completed sampling system was investigated. Different sampling volumes have been tested. It appears that the 10 μl volume has produced data that had much smaller relative standard deviations than the 2 μl volume. In addition, the production of a less expensive, mass produced sampling chip was investigated to avoid chip reuse thus increasing sampling reproducibility/accuracy. The micro-fluidic-based robotic sampling system's mechanical elements were tested to ensure analytical reproducibility and the optimum robotic handling of micro-fluidic sampling chips. (authors)

  2. A microdevice assisted approach for the preparation, characterization and selection of continuous aqueous two-phase systems: from micro to bench-scale.

    Science.gov (United States)

    Vázquez-Villegas, Patricia; Ouellet, Eric; González, Claudia; Ruiz-Ruiz, Federico; Rito-Palomares, Marco; Haynes, Charles A; Aguilar, Oscar

    2016-07-01

    Aqueous two-phase systems (ATPS) have emerged as an alternative strategy for the recovery and purification of a wide variety of biological products. Typical process development requires a large screening of experimental conditions towards industrial adoption where continuous processes are preferred. In this work, it was proved that under certain flow conditions, ATPS could be formed continuously inside a microchannel, starting from stocks of phase components. Staggered herringbone chaotic micromixers included within the device sequentially and rapidly prepare two-phase systems across an entire range of useful phase compositions. Two-phase diagrams (binodal curves) were easily plotted using the cloud-point method for systems of different components and compared with previously reported curves for each system, proving that phase formation inside the device correlated with the previously reported diagrams. A proof of concept for sample partitioning in such a microdevice was performed with two different experimental models: BSA and red blood cells. Finally, the microdevice was employed to obtain information about the recovery and partition coefficient of invertase from a real complex mixture of proteins (yeast extract) to design a process for the recovery of the enzyme selecting a suitable system and composition to perform the process at bench-scale. PMID:27302418

  3. Phase separation of biphasic mixture of active Janus colloids

    Science.gov (United States)

    Yan, Jing; Han, Ming; Luijten, Erik; Granick, Steve

    2014-03-01

    Recently there is a surge of interest in the phase behavior of active matter in which building blocks display self-propelling motion. Although much has been known from theory and simulation, experimental examples are very rare. Specifically, the epitomic problem of a binary mixture of active matter defies any experiment or theory so far. Here we present an experimental realization of binary mixture of particles, which only acquires activity when they collisionally interact with the opposite kind. We used a system in which the only difference in the two particles is the phase in their cyclic motion, precluding any artifact due to difference in interparticle potential. We observe phenomena strikingly similar to spinodal decomposition of molecular system, in addition to new features due to the nonequilibrium nature of the system. We derived a general, effective Flory-Huggins theory for spinodal decomposition of bicomponent active system, and rationalized the 1/3 power law growth of the domain size in regions where thermodynamic analogy is valid. The system also presents a plethora of nonequilibrium phenomena such as critical fluctuation, lane formation, and dynamic absorbing state in different parameter space.

  4. Surface tensions of multi-component mixed inorganic/organic aqueous systems of atmospheric significance: measurements, model predictions and importance for cloud activation predictions

    Directory of Open Access Journals (Sweden)

    D. O. Topping

    2006-11-01

    Full Text Available In order to predict the physical properties of aerosol particles, it is necessary to adequately capture the behaviour of the ubiquitous complex organic components. One of the key properties which may affect this behaviour is the contribution of the organic components to the surface tension of aqueous particles in the moist atmosphere. Whilst the qualitative effect of organic compounds on solution surface tensions has been widely reported, our quantitative understanding on mixed organic and mixed inorganic/organic systems is limited.  Furthermore, it is unclear whether models that exist in the literature can reproduce the surface tension variability for binary and higher order multi-component organic and mixed inorganic/organic systems of atmospheric significance. The current study aims to resolve both issues to some extent. Surface tensions of single and multiple solute aqueous solutions were measured and compared with predictions from a number of model treatments. On comparison with binary organic systems, two predictive models found in the literature provided a range of values resulting from sensitivity to calculations of pure component surface tensions.  Results indicate that a fitted model can capture the variability of the measured data very well, producing the lowest average percentage deviation for all compounds studied.  The performance of the other models varies with compound and choice of model parameters. The behaviour of ternary mixed inorganic/organic systems was unreliably captured by using a predictive scheme and this was composition dependent. For more "realistic" higher order systems, entirely predictive schemes performed poorly. It was found that use of the binary data in a relatively simple mixing rule, or modification of an existing thermodynamic model with parameters derived from binary data, was able to accurately capture the surface tension variation with concentration. Thus, it would appear that in order to model

  5. (Liquid + liquid) and (liquid + solid) equilibrium of aqueous two-phase systems containing poly ethylene glycol di-methyl ether 2000 and di-sodium hydrogen phosphate

    International Nuclear Information System (INIS)

    (Liquid + liquid) equilibrium (LLE) for the {poly ethylene glycol di-methyl ether 2000 (PEGDME2000) + Na2HPO4 + H2O} system have been determined experimentally at T = (298.15, 308.15, 313.15, and 318.15) K. The effects of temperature on the binodals and tie-lines for the investigated aqueous two-phase system (ATPS) have been studied. An empirical non-linear expression developed by Merchuk was used for reproducing the experimental binodal data. In this work, the three fitting parameters of the Merchuk equation were obtained with the temperature dependence expressed in the linear form with (T - T0) K as a variable. Furthermore, the modified local composition segment-based NRTL and Wilson models and also osmotic virial equation were used to describe the LLE data of the studied system. Also, the effects of the type of salt on LLE are discussed. In addition, the effects of end groups of the polymers PEGDME2000 and poly ethylene glycol 2000 on phase forming ability were studied. The complete phase diagram for the poly ethylene {glycol di-methyl ether 2000 (PEGDME2000) + Na2HPO4 + H2O} system has also been determined at T = 298.15 K.

  6. Direct Purification of Pectinase from Mango (Mangifera Indica Cv. Chokanan Peel Using a PEG/Salt-Based Aqueous Two Phase System

    Directory of Open Access Journals (Sweden)

    Abdul Manap Mohd Yazid

    2011-10-01

    Full Text Available An Aqueous Two-Phase System (ATPS was employed for the first time for the separation and purification of pectinase from mango (Mangifera Indica Cv. Chokanan peel. The effects of different parameters such as molecular weight of the polymer (polyethylene glycol, 2,000–10,000, potassium phosphate composition (12–20%, w/w, system pH (6–9, and addition of different concentrations of neutral salts (0–8%, w/w on partition behavior of pectinase were investigated. The partition coefficient of the enzyme was decreased by increasing the PEG molecular weight. Additionally, the phase composition showed a significant effect on purification factor and yield of the enzyme. Optimum conditions for purification of pectinase from mango peel were achieved in a 14% PEG 4000-14% potassium phosphate system using 3% (w/w NaCl addition at pH 7.0. Based on this system, the purification factor of pectinase was increased to 13.2 with a high yield of (97.6%. Thus, this study proves that ATPS can be an inexpensive and effective method for partitioning of pectinase from mango peel.

  7. EQ3/6, a software package for geochemical modeling of aqueous systems: Package overview and installation guide (Version 7.0)

    Energy Technology Data Exchange (ETDEWEB)

    Wolery, T.J.

    1992-09-14

    EQ3/6 is a software package for geochemical modeling of aqueous systems. This report describes version 7.0. The major components of the package include: EQ3NR, a speciation-solubility code; EQ6, a reaction path code which models water/rock interaction or fluid mixing in either a pure reaction progress mode or a time mode; EQPT, a data file preprocessor, EQLIB, a supporting software library; and five supporting thermodynamic data files. The software deals with the concepts of thermodynamic equilibrium, thermodynamic disequilibrium, and reaction kinetics. The five supporting data files contain both standard state and activity coefficient-related data. Three support the use of the Davies or B-dot equations for the activity coefficients; the other two support the use of Pitzer`s equations. The temperature range of the thermodynamic data on the data files varies from 25{degree}C only to 0--300{degree}C. EQPT takes a formatted data file (a data0 file) and writes an unformatted near-equivalent called a datal file, which is actually the form read by EQ3NR and EQ6. EQ3NR is useful for analyzing groundwater chemistry data, calculating solubility limits, and determining whether certain reactions are in states of partial equilibrium or disequilibrium. It is also required to initialize an EQ6 calculation. EQ6 models the consequences of reacting an aqueous solution with a set of reactants which react irreversibly. It can also model fluid mixing and the consequences of changes in temperature. This code operates both in a pure reaction progress frame and in a time frame.

  8. EQ3/6, a software package for geochemical modeling of aqueous systems: Package overview and installation guide (Version 7.0)

    International Nuclear Information System (INIS)

    EQ3/6 is a software package for geochemical modeling of aqueous systems. This report describes version 7.0. The major components of the package include: EQ3NR, a speciation-solubility code; EQ6, a reaction path code which models water/rock interaction or fluid mixing in either a pure reaction progress mode or a time mode; EQPT, a data file preprocessor, EQLIB, a supporting software library; and five supporting thermodynamic data files. The software deals with the concepts of thermodynamic equilibrium, thermodynamic disequilibrium, and reaction kinetics. The five supporting data files contain both standard state and activity coefficient-related data. Three support the use of the Davies or B equations for the activity coefficients; the other two support the use of Pitzer's equations. The temperature range of the thermodynamic data on the data files varies from 25 degree C only to 0--300 degree C. EQPT takes a formatted data file (a data0 file) and writes an unformatted near-equivalent called a datal file, which is actually the form read by EQ3NR and EQ6. EQ3NR is useful for analyzing groundwater chemistry data, calculating solubility limits, and determining whether certain reactions are in states of partial equilibrium or disequilibrium. It is also required to initialize an EQ6 calculation. EQ6 models the consequences of reacting an aqueous solution with a set of reactants which react irreversibly. It can also model fluid mixing and the consequences of changes in temperature. This code operates both in a pure reaction progress frame and in a time frame

  9. Velocity dependence of biphasic flow structuration: steady-state and oscillating flow effects

    Science.gov (United States)

    Tore Tallakstad, Ken; Jankov, Mihailo; Løvoll, Grunde; Toussaint, Renaud; Jørgen Mâløy, Knut; Grude Flekkøy, Eirik; Schmittbuhl, Jean; Schäfer, Gerhard; Méheust, Yves; Arendt Knudsen, Henning

    2010-05-01

    We study various types of biphasic flows in quasi-two-dimensional transparent porous models. These flows imply a viscous wetting fluid, and a lowly viscous one. The models are transparent, allowing the displacement process and structure to be monitored in space and time. Three different aspects will be presented: 1. In stationary biphasic flows, we study the relationship between the macroscopic pressure drop (related to relative permeability) and the average flow rate, and how this arises from the cluster size distribution of the lowly viscous fluid [1]. 2. In drainage situations, we study how the geometry of the invader can be explained, and how it gives rise to apparent dynamic capillary effects. We show how these can be explained by viscous effects on evolving geometries of invading fluid [2]. 3. We study the impact of oscillating pressure fields superimposed to a background flow over the flow regimes patterns [3]. Steady-State Two-Phase Flow in Porous Media: Statistics and Transport Properties. First, in stationary flow with a control of the flux of both fluids, we show how the pressure drop depends on the flow rate. We will show that the dynamics is dominated by the interplay between a viscous pressure field from the wetting fluid and bubble transport of a less viscous, nonwetting phase. In contrast with more studied displacement front systems, steady-state flow is in equilibrium, statistically speaking. The corresponding theoretical simplicity allows us to explain a data collapse in the cluster size distribution of lowly viscous fluid in the system, as well as the relation |?P|∞√Ca--. This allows to explain so called relative permeability effects by the morphological changes of the cluster size distribution. Influence of viscous fingering on dynamic saturation-pressure curves in porous media. Next, we study drainage in such models, and investigate the relationship between the pressure field and the morphology of the invading fluid. This allows to model

  10. Extraction of Dengue 2 Plasmid DNA Vaccine (pD2) from Cell Lysates by Aqueous Two-Phase Systems

    OpenAIRE

    Keila Aparecida Moreira; Adilson Castro Chaves; Ernesto Torres Marques; Duarte Miguel Ferreira Prazeres; Walter Mendes de Azevedo; Ana Lucia Figueiredo Porto; Jose Luiz de Lima Filho

    2007-01-01

    This research describes the partitioning in PEG/phosphate systems of the plasmid pD2, a dengue 2 plasmid DNA vaccine, present in a clarified E. coli alkaline lysate. Factors that affect the partition as PEG molecular weight, plasmid concentration and the lysate volume loaded in the system were investigated. Results showed that partition behavior of plasmid DNA depends on the system molecular weight, a considerable amount of protein of the cell lysate was accumulated in the interphase of the s...

  11. Regulation of biphasic drug release behavior by graphene oxide in polyvinyl pyrrolidone/poly(ε-caprolactone) core/sheath nanofiber mats.

    Science.gov (United States)

    Yu, Hui; Yang, Peng; Jia, Yongtang; Zhang, Yumei; Ye, Qiuying; Zeng, Simin

    2016-10-01

    One of the key issues for drug delivery systems is to develop a drug carrier with a time-programmed, biphasic release behavior. Using vancomycin hydrochloride (VAN) as a model drug, polyvinyl pyrrolidone (PVP) blended with graphene oxide (GO) sheets as the core matrix, and poly(ε-caprolactone) (PCL) as the sheath polymer, core/sheath PVP/PCL nanofiber mats were fabricated via a coaxial electrospinning process. We hypothesized that the addition of GO sheets would lead to their molecular interactions with VAN molecules, thereby adjusting the VAN release behavior. Field emission scanning electron microscopy and transmission electron microscopy of the fiber mats revealed their nanofibrous structure and clear core/sheath boundary. Raman analysis demonstrated the presence of GO sheets in the PVP/PCL nanofiber mats. Fourier transform infrared spectroscopy indicated the formation of hydrogen bonds between GO sheets and VAN molecules. In vitro studies showed that the PVP/PCL nanofiber mats were biocompatible, despite the addition of GO sheets, and exhibited typical biphasic drug release profiles, which were tailored by adjusting the content of GO sheets. Furthermore, an antimicrobial test showed different antimicrobial activities of the medicated nanofiber mats, depending on the GO content. Collectively, the results of the present study provide a simple approach to obtaining time-programmed drug release profiles. PMID:27259160

  12. Physicochemical characterization of novel aqueous two-phase system: gemini surfactant 12-2-12/NaBr/H2O.

    Science.gov (United States)

    Yue, Ling; He, Zimeng; Zhu, Yunfeng; Shang, Yazhuo; Liu, Honglai

    2015-04-01

    A novel aqueous two-phase system (ATPS) only containing Gemini surfactant ethanediyl-1,2-bis(dodecyldimethylammonium bromide) and an inorganic salt sodium bromide was designed, and the physicochemical properties of the ATPS were investigated systematically. The results have shown that the coexisting two phases, one surfactant-rich and the other salt-rich, are stable and the phase behavior, volume ratio, and extraction efficiency of ATPS are strongly influenced by contents of surfactant and salt. The novel ATPS here investigated have potential application in partitioning and analysis of biomaterials. Compared with other complicated surfactant-based ATPS, the surfactant concentration for the formation of ATPS is much lower, which implies that the studied system is potentially more economical for purification and separation of biomaterials. Meanwhile, the surfactant can be recycled by altering salt concentration in ATPS. Lyotropic liquid crystal was found in the bottom phase besides micelles under different conditions. The salting-out effect may be the driving force of ATPS formation for the studied "living polymer"/salt system. However, the coexistence of micelles with different microstructures is the necessary condition of phase separation. The current studies not only present a new ATPS for partitioning and analysis of biomaterials but also have a great significance on rational use of Gemini surfactants. PMID:25649445

  13. EQ6, a computer program for reaction path modeling of aqueous geochemical systems: Theoretical manual, user's guide, and related documentation (Version 7.0)

    International Nuclear Information System (INIS)

    EQ6 is a FORTRAN computer program in the EQ3/6 software package (Wolery, 1979). It calculates reaction paths (chemical evolution) in reacting water-rock and water-rock-waste systems. Speciation in aqueous solution is an integral part of these calculations. EQ6 computes models of titration processes (including fluid mixing), irreversible reaction in closed systems, irreversible reaction in some simple kinds of open systems, and heating or cooling processes, as well as solve ''single-point'' thermodynamic equilibrium problems. A reaction path calculation normally involves a sequence of thermodynamic equilibrium calculations. Chemical evolution is driven by a set of irreversible reactions (i.e., reactions out of equilibrium) and/or changes in temperature and/or pressure. These irreversible reactions usually represent the dissolution or precipitation of minerals or other solids. The code computes the appearance and disappearance of phases in solubility equilibrium with the water. It finds the identities of these phases automatically. The user may specify which potential phases are allowed to form and which are not. There is an option to fix the fugacities of specified gas species, simulating contact with a large external reservoir. Rate laws for irreversible reactions may be either relative rates or actual rates. If any actual rates are used, the calculation has a time frame. Several forms for actual rate laws are programmed into the code. EQ6 is presently able to model both mineral dissolution and growth kinetics

  14. Aqueous two-phase system cold-set gelation using natural and recombinant probiotic lactic acid bacteria as a gelling agent.

    Science.gov (United States)

    Léonard, Lucie; Husson, Florence; Langella, Philippe; Châtel, Jean-Marc; Saurel, Rémi

    2016-05-01

    The present study aimed to entrap probiotic lactic acid bacteria (LAB) in a sodium alginate and sodium caseinate aqueous two-phase gel system. The natural acidifying properties of two therapeutic probiotic LAB were exploited to liberate calcium ions progressively from calcium carbonate (CaCO3), which caused the gelation of the co-existing phases. Bi-biopolymeric matrix gelation of GDL/CaCO3 or LAB/CaCO3 was monitored by dynamic rheological measurements, and the final gels were characterized by frequency dependence measurements and confocal laser scanning microscopy. Weak to strong gels were formed with an elastic modulus G' from 10 to 1.000Pa, respectively. After cold-set gelation of our system, confocal laser scanning microscopy showed spherical protein microdomains trapped within a calcium alginate network. LAB cells were stained to study their partition in the self-gelling matrices. Our LAB strains showed two different behaviors, which may relate to the exopolysaccharide production: (i) Lactobacillus plantarum CNRZ1997 cells were found mainly in continuous alginate networks, whereas (ii) Lactococcus lactis cells were localized in protein microdomains. This alginate-caseinate phase-separated system that was self-gelled by LAB cells may be an innovative approach for immobilizing and protecting LAB cells. PMID:26874119

  15. Effect of ph value of aqueous phase on interphase tension of organic acids in the system of tri-n-butyl phosphate

    International Nuclear Information System (INIS)

    The dependence of interphase tension of extractant, usually applied for extraction reprocessing of NPP spent fuel (30% solution of tri-n-butylphosphate in n-dodecane), containing carbonic and dialkylphosphoric acids with a long alkyl chain, on the value of hydrogen index of pH of equilibrium aqueous phase is studied. The data obtained are compared with similar dependences, characteristic of extractant, which does not contain organic acid additions, as well as of extractant irradiated by 60Co γ-source with doses 108 and 432 kGy. It is shown that in irradiated organic solutions, except compounds belonging to the class of dialkylphosphoric acids, at least two more classes of organic derivatives of acid character are present, which differ in the constants of acid dissociation and result in the decrease of interphase tension in the system. Compounds belonging to the class of dialkylphosphoric acids are to a less degree responsible for the decrease in interphase tension in the system than weaker, for instance carbonic, acids. The method can be used for the indentification of different classes of aniongenic surfactants in radiation-affected extraction systems

  16. EQ6, a computer program for reaction path modeling of aqueous geochemical systems: Theoretical manual, user`s guide, and related documentation (Version 7.0); Part 4

    Energy Technology Data Exchange (ETDEWEB)

    Wolery, T.J.; Daveler, S.A.

    1992-10-09

    EQ6 is a FORTRAN computer program in the EQ3/6 software package (Wolery, 1979). It calculates reaction paths (chemical evolution) in reacting water-rock and water-rock-waste systems. Speciation in aqueous solution is an integral part of these calculations. EQ6 computes models of titration processes (including fluid mixing), irreversible reaction in closed systems, irreversible reaction in some simple kinds of open systems, and heating or cooling processes, as well as solve ``single-point`` thermodynamic equilibrium problems. A reaction path calculation normally involves a sequence of thermodynamic equilibrium calculations. Chemical evolution is driven by a set of irreversible reactions (i.e., reactions out of equilibrium) and/or changes in temperature and/or pressure. These irreversible reactions usually represent the dissolution or precipitation of minerals or other solids. The code computes the appearance and disappearance of phases in solubility equilibrium with the water. It finds the identities of these phases automatically. The user may specify which potential phases are allowed to form and which are not. There is an option to fix the fugacities of specified gas species, simulating contact with a large external reservoir. Rate laws for irreversible reactions may be either relative rates or actual rates. If any actual rates are used, the calculation has a time frame. Several forms for actual rate laws are programmed into the code. EQ6 is presently able to model both mineral dissolution and growth kinetics.

  17. Heterogeneous Bunsen reaction : Analysis and experimental study of chemical absorption of sulfur dioxide and dissolution of iodine into aqueous reacting system

    International Nuclear Information System (INIS)

    Bunsen reaction is one of the three main reaction steps of Iodine-Sulphur (I-S) thermochemical water splitting process for production of hydrogen, utilizing nuclear heat. This complex multiphase-multispecies reaction has to be carried out optimally for harnessing the potential of I-S process for large scale production of hydrogen. Apart from strong influence of operating conditions, contacting scheme, reactor type and size have severe bearing on issues like overall process efficiency, product purity, separation, conversion etc. In this study sulphur dioxide (gas) and iodine (solid) are reacted in aqueous solution (liquid) with gas sparging and mechanical agitation at room temperature. Experimental results of this reacting ternary system are analyzed in terms of film theory of mass transfer. Chemical absorption of sulphur dioxide and enhanced dissolution of iodine solid into Bunsen reacting system are interpreted to deduce crucial engineering information like controlling resistance, regime, enhancement factor etc, which will help in selection of suitable contacting scheme and design of multiphase absorber-reactor for large-scale production of hydrogen. Behavior of this fluid-fluid-solid absorber - reactor can be construed kinetically as 'Fast psuedo first order reaction system'. (author)

  18. A new aqueous activity model for geothermal brines in the system Na-K-Ca-Mg-H-Cl-SO4-H2O from 25 to 300 degrees C

    DEFF Research Database (Denmark)

    Hingerl, Ferdinand F.; Wagner, Thomas; Kulik, Dmitrii A.;

    2014-01-01

    A revised formulation (named REUNIQUAC) of the Extended Universal QUAsiChemical (EUNIQUAC) activity model has been developed, which fits excess thermodynamic properties of binary and selected aqueous ternary electrolyte solutions in the system Na-K-Ca-Mg-H-Cl-SO4-H2O over temperatures from 298 to...

  19. The salting-out effect and phase separation in aqueous solutions of tri-sodium citrate and 1-butyl-3-methylimidazolium bromide

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat, E-mail: rsadeghi@uok.ac.i [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Golabiazar, Roonak [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Shekaari, Hemayat [Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of)

    2010-04-15

    The aim of this work is to obtain further evidence about the salting-out effect produced by the addition of tri-sodium citrate to aqueous solutions of water miscible ionic liquid 1-butyl-3-methylimidazolium bromide ([C{sub 4}mim][Br]) by evaluating the effect of tri-sodium citrate on the thermodynamic properties of aqueous solutions of this ionic liquid. Experimental measurements of density and sound velocity at different temperatures ranging from (288.15 to 308.15) K, the refractive index at 308.15 K and the liquid-liquid phase diagram at different temperatures ranging from (288.15 to 338.15) K for aqueous solutions containing 1-butyl-3-methylimidazolium bromide ([C{sub 4}mim][Br]) and tri-sodium citrate (Na{sub 3}Cit) are taken. The apparent molar volume of transfer of [C{sub 4}mim][Br] from water to aqueous solutions of Na{sub 3}Cit have positive values and it increases by increasing salt molality. Although at high IL molality, the apparent molar isentropic compressibility shows similar behaviour with that of the apparent molar volume. However at low concentrations of IL, the apparent molar isentropic compressibility of transfer of [C{sub 4}mim][Br] from water to aqueous solutions of Na{sub 3}Cit have negative values. The effects of temperature and the addition of Na{sub 3}Cit and [C{sub 4}mim][Br] on the liquid-liquid phase diagram of the investigated system have been studied. It was found that an increase in temperature caused the expansion of the one-phase region. The presence of Na{sub 3}Cit triggers a salting-out effect, leading to significant upward shifts of the liquid-liquid de-mixing temperatures of the system. The effect of temperature on the phase-forming ability in the system investigated has been studied based on a salting-out coefficient obtained from fitting the binodal values to a Setschenow-type equation for each temperature. Based on cloud point values, the energetics of the clouding process have been estimated and it was found that both of

  20. The salting-out effect and phase separation in aqueous solutions of tri-sodium citrate and 1-butyl-3-methylimidazolium bromide

    International Nuclear Information System (INIS)

    The aim of this work is to obtain further evidence about the salting-out effect produced by the addition of tri-sodium citrate to aqueous solutions of water miscible ionic liquid 1-butyl-3-methylimidazolium bromide ([C4mim][Br]) by evaluating the effect of tri-sodium citrate on the thermodynamic properties of aqueous solutions of this ionic liquid. Experimental measurements of density and sound velocity at different temperatures ranging from (288.15 to 308.15) K, the refractive index at 308.15 K and the liquid-liquid phase diagram at different temperatures ranging from (288.15 to 338.15) K for aqueous solutions containing 1-butyl-3-methylimidazolium bromide ([C4mim][Br]) and tri-sodium citrate (Na3Cit) are taken. The apparent molar volume of transfer of [C4mim][Br] from water to aqueous solutions of Na3Cit have positive values and it increases by increasing salt molality. Although at high IL molality, the apparent molar isentropic compressibility shows similar behaviour with that of the apparent molar volume. However at low concentrations of IL, the apparent molar isentropic compressibility of transfer of [C4mim][Br] from water to aqueous solutions of Na3Cit have negative values. The effects of temperature and the addition of Na3Cit and [C4mim][Br] on the liquid-liquid phase diagram of the investigated system have been studied. It was found that an increase in temperature caused the expansion of the one-phase region. The presence of Na3Cit triggers a salting-out effect, leading to significant upward shifts of the liquid-liquid de-mixing temperatures of the system. The effect of temperature on the phase-forming ability in the system investigated has been studied based on a salting-out coefficient obtained from fitting the binodal values to a Setschenow-type equation for each temperature. Based on cloud point values, the energetics of the clouding process have been estimated and it was found that both of entropy and enthalpy are the driving forces for biphasic

  1. A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions.

    Science.gov (United States)

    Brack, Paul; Dann, Sandie; Wijayantha, K G Upul; Adcock, Paul; Foster, Simon

    2016-01-01

    There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) hydrogen fuel cells. Researchers seeking to develop such systems require a method of measuring the generated hydrogen. Herein, we describe a simple, low-cost, and robust method to measure the hydrogen generated from the reaction of solids with aqueous solutions. The reactions are conducted in a conventional one-necked round-bottomed flask placed in a temperature controlled water bath. The hydrogen generated from the reaction in the flask is channeled through tubing into a water-filled inverted measuring cylinder. The water displaced from the measuring cylinder by the incoming gas is diverted into a beaker on a balance. The balance is connected to a computer, and the change in the mass reading of the balance over time is recorded using data collection and spreadsheet software programs. The data can then be approximately corrected for water vapor using the method described herein, and parameters such as the total hydrogen yield, the hydrogen generation rate, and the induction period can also be deduced. The size of the measuring cylinder and the resolution of the balance can be changed to adapt the setup to different hydrogen volumes and flow rates. PMID:27584581

  2. Analytical possibilities of different X-ray fluorescence systems for determination of trace elements in aqueous samples pre-concentrated with carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Marguí, E., E-mail: eva.margui@udg.edu [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); Zawisza, B.; Skorek, R. [Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice (Poland); Theato, T. [SPECTRO Analytical Instruments GmbH, Boschstr. 10, 47533 Kleve (Germany); Queralt, I. [Laboratory of X-Ray Analytical Applications, Institute of Earth Sciences Jaume Almera, CSIC, Solé Sabarís s/n, 08028 Barcelona (Spain); Hidalgo, M. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); Sitko, R. [Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice (Poland)

    2013-10-01

    This study was aimed to achieve improved instrumental sensitivity and detection limits for multielement determination of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Se, Pb and Cd in liquid samples by using different X-ray fluorescence (XRF) configurations (a benchtop energy-dispersive X-ray fluorescence spectrometer, a benchtop polarised energy-dispersive X-ray fluorescence spectrometer and a wavelength-dispersive X-ray fluorescence spectrometer). The preconcentration of metals from liquid solutions consisted on a solid-phase extraction using carbon nanotubes (CNTs) as solid sorbents. After the extraction step, the aqueous sample was filtered and CNTs with the absorbed elements were collected onto a filter paper which was directly analyzed by XRF. The calculated detection limits in all cases were in the low ng mL{sup −1} range. Nevertheless, results obtained indicate the benefits, in terms of sensitivity, of using polarized X-ray sources using different secondary targets in comparison to conventional XRF systems, above all if Cd determination is required. The developed methodologies, using the aforementioned equipments, have been applied for multielement determination in water samples from an industrial area of Poland. - Highlights: • Use of carbon nanotubes for preconcentration of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Se, Pb and Cd • Combination of this preconcentration procedure with different XRF systems • Benefit of using polarized X-ray sources for trace element determination.

  3. Polymeric Amorphous Solid Dispersions: A Review of Amorphization, Crystallization, Stabilization, Solid-State Characterization, and Aqueous Solubilization of Biopharmaceutical Classification System Class II Drugs.

    Science.gov (United States)

    Baghel, Shrawan; Cathcart, Helen; O'Reilly, Niall J

    2016-09-01

    Poor water solubility of many drugs has emerged as one of the major challenges in the pharmaceutical world. Polymer-based amorphous solid dispersions have been considered as the major advancement in overcoming limited aqueous solubility and oral absorption issues. The principle drawback of this approach is that they can lack necessary stability and revert to the crystalline form on storage. Significant upfront development is, therefore, required to generate stable amorphous formulations. A thorough understanding of the processes occurring at a molecular level is imperative for the rational design of amorphous solid dispersion products. This review attempts to address the critical molecular and thermodynamic aspects governing the physicochemical properties of such systems. A brief introduction to Biopharmaceutical Classification System, solid dispersions, glass transition, and solubility advantage of amorphous drugs is provided. The objective of this review is to weigh the current understanding of solid dispersion chemistry and to critically review the theoretical, technical, and molecular aspects of solid dispersions (amorphization and crystallization) and potential advantage of polymers (stabilization and solubilization) as inert, hydrophilic, pharmaceutical carrier matrices. In addition, different preformulation tools for the rational selection of polymers, state-of-the-art techniques for preparation and characterization of polymeric amorphous solid dispersions, and drug supersaturation in gastric media are also discussed. PMID:26886314

  4. Extraction protease expressed by Penicillium fellutanum from the Brazilian savanna using poly(ethylene glycol)/sodium polyacrylate/NaCl aqueous two-phase system.

    Science.gov (United States)

    Barros, Kleber V G; Souza, Paula M; Cardoso, Samuel L; Borges, Leonardo L; Filho, Edivaldo X F; Junior, Adalberto P; Magalhães, Pérola O

    2015-01-01

    The partitioning of protease expressed by Penicillium fellutanum from the Brazilian savanna in a novel inexpensive and stable aqueous two-phase system (ATPS) composed of poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) was studied in this work using factorial design. The ATPS is formed by mixing both polymers with a salt (NaCl) and fermented broth of P. fellutanum. The effects of molar mass (2,000, 4,000, and 6,000 g ⋅ mol(-1)) and concentration (6, 8, and 10 wt%) of PEG and that of NaPA concentration (6, 8, and 10 wt%) on protease partitioning (K) at 25 °C were studied. A two-level factorial design (2(3)) was implemented. The effect of Na2 SO4 concentration (5, 10, and 15 wt%) on the reextraction of the enzyme was also analyzed. The partition coefficient K ranged from 77.51 to 1.21, indicating the versatility of the method. The reextraction was achieved with the addition of 5% Na2 SO4 , allowing the partitioning of the protease to the upper phase, whereas total proteins were directed to the bottom phase. The results of partitioning using the PEG/NaPA/NaCl system and that of the subsequent reextraction with Na2 SO4 suggest that this method can be used to purify proteases from fermented broth of P. fellutanum. PMID:25546578

  5. The use of microelectrodes for the In-situ monitoring of the chemistry of aqueous coolants in heat-transport systems of nuclear reactors

    International Nuclear Information System (INIS)

    In contrast to conventional amperometric electrodes, amperometric microelectrodes exhibit certain unique characteristics that make them well suited as sensors in the dilute aqueous electrolytes. The heat-transport systems (HTSs) of thermal power plants employ such electrolytes as coolants at elevated temperatures and pressures. Thus, amperometric microelectrodes are in principle well suited for the in-situ monitoring of HTS coolant chemistry. This report describes the experimental evaluation of a platinum microdisc electrode for one such application. The results of these experiments demonstrate that microelectrodes can be used to monitor the concentration of dissolved oxygen in simulated HTS coolants at 150 degrees C in the concentration range of 10-1000 ppb. Measurements of open-circuit potential, commonly referred to as ECP, are currently being made from platinum electrodes installed in the HTSs of a number of nuclear reactors. The availability of platinum microelectrodes capable of functioning under HTS conditions offers the prospect of replacing the conventional electrodes with microelectrodes. Such a strategy would allow the use of a variety of more advanced electrochemical techniques that involve the polarization of the electrode from its open-circuit potential through the external application of potential. Thus, the utility of electrochemical monitors could be significantly enhanced for minimal additional expense while maintaining probe and system reliability. (author)

  6. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride–Molecular Ni Catalyst System

    Science.gov (United States)

    2016-01-01

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride (NCNCNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The NCNCNx–NiP system showed an activity of 763 μmol (g CNx)−1 h–1 toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h–1, and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of NCNCNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited NCNCNx in the presence of an organic substrate can accumulate ultralong-lived “trapped electrons”, which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel. PMID:27337491

  7. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride-Molecular Ni Catalyst System.

    Science.gov (United States)

    Kasap, Hatice; Caputo, Christine A; Martindale, Benjamin C M; Godin, Robert; Lau, Vincent Wing-Hei; Lotsch, Bettina V; Durrant, James R; Reisner, Erwin

    2016-07-27

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride ((NCN)CNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The (NCN)CNx-NiP system showed an activity of 763 μmol (g CNx)(-1) h(-1) toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h(-1), and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of (NCN)CNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited (NCN)CNx in the presence of an organic substrate can accumulate ultralong-lived "trapped electrons", which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel. PMID:27337491

  8. Prediction of liquid-liquid equilibria for polyethylene glycol based aqueous two-phase system by ASOG and UNIFAC method

    Directory of Open Access Journals (Sweden)

    M. Perumalsamy

    2009-03-01

    Full Text Available Liquid-Liquid equilibrium data were obtained for the polyethylene glycol2000(PEG2000-sodium citrate-water system at 298.15, 308.15 and 318.15 K. The effect of temperature on binodal and tie line data was studied and published in a previous article (Murugesan and Perumalsamy, 2005. The interaction parameters of ASOG and UNIFAC models were estimated using the LLE data of PEG2000-sodium citrate-water system and are used to predict the LLE data for PEG6000-sodium citrate-water system at 298.15, 308.15 and 318.15 K (literature data. The predicted LLE data by both ASOG and UNIFAC models showed good agreement with the experimental and literature data.

  9. Biphasic modulation of Wnt signaling supports efficient foregut endoderm formation from human pluripotent stem cells.

    Science.gov (United States)

    Hoepfner, Jeannine; Kleinsorge, Mandy; Papp, Oliver; Ackermann, Mania; Alfken, Susanne; Rinas, Ursula; Solodenko, Wladimir; Kirschning, Andreas; Sgodda, Malte; Cantz, Tobias

    2016-05-01

    Pluripotent stem cells (embryonic stem cells and induced pluripotent stem cells) are of great promise in regenerative medicine, including molecular studies of disease mechanisms, if the affected cell type can be authentically generated during in vitro differentiation. Most existing protocols aim to mimic embryonic development steps by the supplementation of specific cytokines and small molecules, but the involved signaling pathways need further exploration. In this study, we investigated enhanced initial activation of Wnt signaling for definitive endoderm formation and subsequent rapid shutdown of Wnt signaling for proper foregut endoderm specification using 3 μM CHIR99021 and 0.5 μg/mL of secreted frizzled-related protein 5 (sFRP-5) for biphasic modulation of the Wnt pathway. The definitive endoderm and foregut endoderm differentiation capabilities of Wnt pathway-modulated cells were determined based on the expression levels of the endodermal transcription factors SOX17 and FOXA2 and those of the transcription activator GATA4 and the α-fetoprotein (AFP) gene, respectively. Furthermore, the resulting biphasic Wnt pathway modulation was investigated at the protein level by analyzing phosphorylation of glycogen synthase kinase 3 beta (GSK3β) and β-catenin. Finally, Wnt target gene expression was determined using an improved lentiviral reporter construct that enabled robust T-cell transcription factor 4 (TCF4)/lymphoid enhancer-binding factor 1 (LEF1)-mediated luciferase expression in differentiating pluripotent stem cells. In conclusion, we demonstrated robust, homogeneous, and efficient derivation of foregut endodermal cells by inducing a biphasic modulation of the Wnt signaling pathway. PMID:26861571

  10. Modeling of 1-1-electrolyte solubility processes in ternary aqueous-organic systems using Chen's theory

    International Nuclear Information System (INIS)

    A model for the calculation of MCl electrolyte salting-out process (M = Na - Cs) in water-organic media is suggested on the basis of the Chen model for aquerous solutions of electrolytes and the Izmailov continual approximation. For the calculations made for unstudied systems the values of couple interaction parameters, obtained by the optimization of coefficients of the given electrolyte activity in water and coefficient B by the results of calculation of the given electrolyte solubility in one of the known systems, are required

  11. A Galerkin least-square stabilisation technique for hyperelastic biphasic soft tissue

    CERN Document Server

    Vignollet, Julien; Kaczmarczyk, Lukasz

    2011-01-01

    An hyperelastic biphasic model is presented. For slow-draining problems (permeability less than 1\\times10-2 mm4 N-1 s-1), numerical instabilities in the form of non-physical oscillations in the pressure field are observed in 3D problems using tetrahedral Taylor-Hood finite elements. As an alternative to considerable mesh refinement, a Galerkin least-square stabilization framework is proposed. This technique drastically reduces the pressure discrepancies and prevents these oscillations from propagating towards the centre of the medium. The performance and robustness of this technique are demonstrated on a 3D numerical example.

  12. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip–Cleft Palate

    Science.gov (United States)

    George, Lovya; Jain, Sunil K.

    2015-01-01

    Preterm infants (PIs) often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure. PMID:26495158

  13. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip–Cleft Palate

    Directory of Open Access Journals (Sweden)

    Lovya George

    2015-10-01

    Full Text Available Preterm infants (PIs often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure.

  14. Interaction between hydroxypropyl methylcellulose and biphasic calcium phosphate after steam sterilisation: capillary gas chromatography studies.

    OpenAIRE

    Bourges, Xavier; Schmitt, Michel; Amouriq, Yves; Daculsi, Guy; Legeay, Gilbert; Pierre WEISS

    2001-01-01

    The purpose of this study was to check the chemical stability of an injectable bone substitute (IBS) composed of a 50/50 w/w mixture of a 2.92% hydroxypropyl methylcellulose (HPMC) solution in deionised water containing biphasic calcium phosphate (BCP) granules (60% hydroxyapatite/40% β-tricalcium phosphate w/w). After separation of the organic and mineral phases, capillary gas chromatography (GC) was used to study the possible modification of HPMC due to the contact with BCP granules followi...

  15. Biphasic Dose Response in Low Level Light Therapy – An Update

    OpenAIRE

    Huang, Ying-Ying; Sharma, Sulbha K.; Carroll, James; Hamblin, Michael R.

    2011-01-01

    Low-level laser (light) therapy (LLLT) has been known since 1967 but still remains controversial due to incomplete understanding of the basic mechanisms and the selection of inappropriate dosimetric parameters that led to negative studies. The biphasic dose-response or Arndt-Schulz curve in LLLT has been shown both in vitro studies and in animal experiments. This review will provide an update to our previous (Huang et al. 2009) coverage of this topic. In vitro mediators of LLLT such as adenos...

  16. Activated microglia in acute encephalopathy with biphasic seizures and late reduced diffusion.

    Science.gov (United States)

    Fujita, Yuji; Takanashi, Jun-Ichi; Takei, Haruka; Ota, Setsuo; Fujii, Katsunori; Sakuma, Hiroshi; Hayashi, Masaharu

    2016-07-15

    Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype of infectious pediatric encephalopathy in Japan. The exact pathogenesis of and the best therapeutic strategy for AESD are uncertain. We firstly performed a brain biopsy in a 2-year-old boy with AESD associated with RS viral infection, which revealed activated ameoboid microglia accumulation around degenerated neuron, and astrogliosis in the affected cortex. Glutamate released from activated microglia may play an important role in the pathogenesis of AESD, which is compatible with the previous report of magnetic resonance spectroscopy showing elevated glutamate. PMID:27288783

  17. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip-Cleft Palate.

    Science.gov (United States)

    George, Lovya; Jain, Sunil K

    2015-10-01

    Preterm infants (PIs) often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure. PMID:26495158

  18. Development and evaluation of TUMS medium, a novel biphasic culture medium for isolation of Brucella spp. from patients

    Directory of Open Access Journals (Sweden)

    MJ Hejazi

    2009-11-01

    Full Text Available Background and objectives: There are limitations in time and technique for isolation of Brucella from patients. We developed a new Brucella culture medium and evaluated its efficiency compared to BACTEC blood culture system and serology."nMaterials and Methods: A bi-phasic medium containing Urea agar and Brain Heart Infusion was formulated. Appearance of clear red color in liquid phase was the basis of positivity for Brucella. The new medium which is designated as TUMS medium (TUMS refers to Tehran University of Medical Sciences and BACTEC blood culture vials were inoculated with different concentrations of 20 Brucella strains. The blood samples from 58 suspected patients were tested by both media and serology (Wright and Coombs. Any growth was sub-cultured and suspected colonies were identified by standard methods."nResults: The TUMS medium detected more positive samples (100% than BACTEC (85% when the organism was suspended at lower concentration (10 CFU. Of 58 blood cultures, 47 (81% samples tested on TUMS medium (incubation period =4.2 days and 39 (67.2 % samples tested on BACTEC (incubation period =3.3 days were found positive."nConclusion: The TUMS medium was superior to others in detecting the organism from patients with clinical signs or who took medications for >1year. The TUMS medium is easy to prepare and use in endemic areas where resources are limited.

  19. Surface tensions of multi-component mixed inorganic/organic aqueous systems of atmospheric significance: measurements, model predictions and importance for cloud activation predictions

    Directory of Open Access Journals (Sweden)

    D. O. Topping

    2007-01-01

    Full Text Available In order to predict the physical properties of aerosol particles, it is necessary to adequately capture the behaviour of the ubiquitous complex organic components. One of the key properties which may affect this behaviour is the contribution of the organic components to the surface tension of aqueous particles in the moist atmosphere. Whilst the qualitative effect of organic compounds on solution surface tensions has been widely reported, our quantitative understanding on mixed organic and mixed inorganic/organic systems is limited. Furthermore, it is unclear whether models that exist in the literature can reproduce the surface tension variability for binary and higher order multi-component organic and mixed inorganic/organic systems of atmospheric significance. The current study aims to resolve both issues to some extent. Surface tensions of single and multiple solute aqueous solutions were measured and compared with predictions from a number of model treatments. On comparison with binary organic systems, two predictive models found in the literature provided a range of values resulting from sensitivity to calculations of pure component surface tensions. Results indicate that a fitted model can capture the variability of the measured data very well, producing the lowest average percentage deviation for all compounds studied. The performance of the other models varies with compound and choice of model parameters. The behaviour of ternary mixed inorganic/organic systems was unreliably captured by using a predictive scheme and this was dependent on the composition of the solutes present. For more atmospherically representative higher order systems, entirely predictive schemes performed poorly. It was found that use of the binary data in a relatively simple mixing rule, or modification of an existing thermodynamic model with parameters derived from binary data, was able to accurately capture the surface tension variation with concentration. Thus

  20. Multiphase surfactant-assisted reaction-separation system in a microchannel reactor

    Institute of Scientific and Technical Information of China (English)

    Salah ALJBOUR; Tomohiko TAGAWA; Mohammad MATOUQ; Hiroshi YAMADA

    2009-01-01

    The Lewis acid-catalyzed addition of tri-methylsilyl cyanide to p-chlorobenzaldehyde in a micro-channel reactor was investigated. The microchannel was integrated to promote both reaction and separation of the biphase system. FeF3 and Cu(triflate)2 were used as water-stable Lewis acid catalysts. Sodium dodecyl sulfate was incorporated in the organic-aqueous system to enhance the reactivity and to manipulate the multiphase flow inside the microchannel. It was found that the dynamics and the kinetics of the multiphase reaction were affected by the new micellar system. Parallel multiphase flow inside the microchannel was obtained, allowing for continuous and acceptable phase separation. Enhanced selectivity was achieved by operating at lower conversion values.