WorldWideScience

Sample records for high aqueous solubility

  1. Aqueous solubility, dispersibility and toxicity of biodiesels

    Energy Technology Data Exchange (ETDEWEB)

    Hollebone, B.P.; Fieldhouse, B.; Lumley, T.C.; Landriault, M. [Environment Canada, Ottawa, ON (Canada). ; Doe, K.; Jackman, P. [Environment Canada, Moncton, NB (Canada). Toxicology Laboratory, Environmental Science Centre

    2007-07-01

    The renewed interest in the use of biological fuels can be attributed to that fact that feedstocks for fatty-acid ester biodiesels are renewable and can be reclaimed from waste. Although there are significant benefits to using biodiesels, their increased use leaves potential for accidental release to the environment. Therefore, their environmental behaviours and impacts must be evaluated along with the risk associated with their use. Biodiesel fuels may be made from soy oil, canola oil, reclaimed restaurant grease, fish oil and animal fat. The toxicological fate of biofuel depends on the variability of its chemical composition. This study provided an initial assessment of the aqueous fate and effects of biodiesel from a broad range of commonly available feedstocks and their blends with petroleum diesels. The study focused primarily on the fate and impact of these fuels in fresh-water. The use of chemical dispersion as a countermeasure for saltwater was also investigated. The exposure of aquatic ecosystems to biodiesels and petroleum diesel occurs via the transfer of material from the non-aqueous phase liquid (NAPL) into the aqueous phase, as both soluble and dispersed components. The aqueous solubilities of the fuels were determined from the equilibrium water-accommodated fraction concentrations. The acute toxicities of many biodiesels were reported for 3 test species used by Environment Canada for toxicological evaluation, namely rainbow trout, the water flea and a luminescent bacterium. This study also evaluated the natural potential for dispersion of the fuels in the water column in both low and high-energy wave conditions. Chemical dispersion as a potential countermeasure for biodiesel spills was also evaluated using solubility testing, acute toxicity testing, and dispersibility testing. It was shown that biodiesels have much different fates and impacts from petroleum diesels. The compounds partitioning into the water column are also very different for each

  2. Aqueous solubility prediction: do crystal lattice interactions help?

    Science.gov (United States)

    Salahinejad, Maryam; Le, Tu C; Winkler, David A

    2013-07-01

    Aqueous solubility is a very important physical property of small molecule drugs and drug candidates but also one of the most difficult to predict accurately. Aqueous solubility plays a major role in drug delivery and pharmacokinetics. It is believed that crystal lattice interactions are important in solubility and that including them in solubility models should improve the accuracy of the models. We used calculated values for lattice energy and sublimation enthalpy of organic molecules as descriptors to determine whether these would improve the accuracy of the aqueous solubility models. Multiple linear regression employing an expectation maximization algorithm and a sparse prior (MLREM) method and a nonlinear Bayesian regularized artificial neural network with a Laplacian prior (BRANNLP) were used to derive optimal predictive models of aqueous solubility of a large and highly diverse data set of 4558 organic compounds over a normal ambient temperature range of 20-30 °C (293-303 K). A randomly selected test set and compounds from a solubility challenge were used to estimate the predictive ability of the models. The BRANNLP method showed the best statistical results with squared correlation coefficients of 0.90 and standard errors of 0.645-0.665 log(S) for training and test sets. Surprisingly, including descriptors that captured crystal lattice interactions did not significantly improve the quality of these aqueous solubility models.

  3. Computational Analysis of Aqueous Drug Solubility – Influence of the Solid State

    OpenAIRE

    Wassvik, Carola

    2006-01-01

    Aqueous solubility is a key parameter influencing the bioavailability of drugs and drug candidates. In this thesis computational models for the prediction of aqueous drug solubility were explored. High quality experimental solubility data for drugs were generated using a standardised protocol and models were developed using multivariate data analysis tools and calculated molecular descriptors. In addition, structural features associated with either solid-state limited or solvation limited sol...

  4. Solubility of hydrogen sulfide in aqueous solutions of N-methyldiethanolamine at high pressures

    DEFF Research Database (Denmark)

    Sadegh, Negar; Thomsen, Kaj; Solbraa, Even

    2015-01-01

    A static-analytic method was used to measure the H2S solubility in 50 wt% MDEA and in presence of methane as a makeup gas. The solubility was measured at 7000 kPa total pressure, and at 50 and 70 degrees C, for H2S partial pressures from 31 to 974 kPa. Measurements were also performed at 1500 kPa...... to be dominated by the non-ideality of the gas, and it could be predicted by the pressure effect on the fugacity coefficient of H2S in the gas phase. The experimental data from this work are compared and shown to be consistent with earlier published data.......A static-analytic method was used to measure the H2S solubility in 50 wt% MDEA and in presence of methane as a makeup gas. The solubility was measured at 7000 kPa total pressure, and at 50 and 70 degrees C, for H2S partial pressures from 31 to 974 kPa. Measurements were also performed at 1500 k...

  5. Aqueous solubilities of phenol derivatives by conductivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Achard, C.; Jaoui, M.; Schwing, M.; Rogalski, M. [Univ. de Metz (France). Lab. de Thermodynamique et d`Analyse Chimique

    1996-05-01

    The aqueous solubilities of five chlorophenols and three nitrophenols were measured by conductimetry at temperatures between 15 and 48C. The solubilities of 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol, 2-nitrophenol, 4-nitrophenol, and 2,4-dinitrophenol were studied. Automatic conductivity measurements allow the determination of the solute concentration and, hence, the determination of the solubility. Emulsion formation can also be followed. Results obtained are in good agreement with literature values.

  6. Chemiluminescent nitrogen detection (CLND) to measure kinetic aqueous solubility.

    Science.gov (United States)

    Kestranek, Aimee; Chervenak, Andrew; Longenberger, Justin; Placko, Steven

    2013-01-01

    Solubility is the dose-limiting property for in vitro studies, and therefore is a critical physicochemical property to measure in drug discovery. Solubility data can be used to guide lead optimization, troubleshoot erratic bioassay results, and identify potential downstream liabilities such as insufficient solubility for bioassays or oral bioavailability. Typically, early in vitro studies are performed using library compounds prepared as dimethylsulfoxide (DMSO) stock solutions, resulting in in vitro test solutions containing DMSO at low concentration (<5% v/v). Since DMSO can affect the apparent solubility, it is desirable to obtain solubility data under conditions mimicking the in vitro study. Kinetic solubility (from DMSO stock solutions) is often preferred over thermodynamic solubility (from dry powder) in early drug discovery. The protocols in this article describe a general procedure for assessing kinetic aqueous solubility of early drug discovery compounds using a miniaturized shake flask method with chemiluminescent nitrogen detection (CLND).

  7. Thermodynamics of Highly Supersaturated Aqueous Solutions of Poorly Water-Soluble Drugs-Impact of a Second Drug on the Solution Phase Behavior and Implications for Combination Products.

    Science.gov (United States)

    Trasi, Niraj S; Taylor, Lynne S

    2015-08-01

    There is increasing interest in formulating combination products that contain two or more drugs. Furthermore, it is also common for different drug products to be taken simultaneously. This raises the possibility of interactions between different drugs that may impact formulation performance. For poorly water-soluble compounds, the supersaturation behavior may be a critical factor in determining the extent of oral absorption. The goal of the current study was to evaluate the maximum achievable supersaturation for several poorly water-soluble compounds alone, and in combination. Model compounds included ritonavir, lopinavir, paclitaxel, felodipine, and diclofenac. The "amorphous solubility" for the pure drugs was determined using different techniques and the change in this solubility was then measured in the presence of differing amounts of a second drug. The results showed that "amorphous solubility" of each component in aqueous solution is substantially decreased by the second component, as long as the two drugs are miscible in the amorphous state. A simple thermodynamic model could be used to predict the changes in solubility as a function of composition. This information is of great value when developing co-amorphous or other supersaturating formulations and should contribute to a broader understanding of drug-drug physicochemical interactions in in vitro assays as well as in the gastrointestinal tract.

  8. Prediction of the Aqueous Solubilities of Polychlorinated Biphenyls

    Institute of Scientific and Technical Information of China (English)

    Shu Shen LIU; Shi Hai CUI; Lian Sheng WANG

    2004-01-01

    Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the aqueous solubilities of polychlorinated biphenyls(PCBs)were predicted. A three-variable regression equation with correlation coefficient of 0.9739 and the root mean square errors of 0.26 was developed. The descriptors included in the equation represent three interactions between three pairs of atomic types,I.e.,atom-C=and>C=,-C=and-Cl,and-Cland-Cl.It has been proved that the aqueous solubilities of 137 PCB congeners can be accurately predicted as long as there are more than 65 calibration compounds.

  9. Solubility of carbon dioxide in aqueous piperazine solutions

    NARCIS (Netherlands)

    Derks, P. W. J.; Dijkstra, H. B. S.; Hogendoorn, J. A.; Versteeg, G. F.

    2005-01-01

    In the present work, new experimental data are presented on the solubility of carbon dioxide in aqueous piperazine solutions, for concentrations of 0.2 and 0.6 molar piperazine and temperatures of 25, 40, and 70°C respectively. The present data, and other data available in the literature, were

  10. Solubility of carbon dioxide in aqueous piperazine solutions

    NARCIS (Netherlands)

    Derks, P. W. J.; Dijkstra, H. B. S.; Hogendoorn, J. A.; Versteeg, G. F.

    2005-01-01

    In the present work, new experimental data are presented on the solubility of carbon dioxide in aqueous piperazine solutions, for concentrations of 0.2 and 0.6 molar piperazine and temperatures of 25, 40, and 70°C respectively. The present data, and other data available in the literature, were corr

  11. Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter ...

    African Journals Online (AJOL)

    Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof. ... off-gas of the high-temperature processes, which are cleaned by means of venturi scrubbers or bag filter dust (BFD) systems. ... Article Metrics.

  12. Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate

    Science.gov (United States)

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

    2016-01-01

    Purpose The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate. Methods Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP) and Labrafil® M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion. Results All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1:4:0.5 resulted in a particle size of amorphous state. It demonstrated the highest solubility (32.51±2.41 μg/mL), an excellent dissolution (~85% in 10 minutes), and an oral bioavailability ~2.5-fold better than that of the free drug. It showed similar oral bioavailability compared to the conventional solid dispersion. Conclusion Electrosprayed nanospherules, which provide improved solubility and bioavailability, are promising drug delivery tools for oral administration of poorly water-soluble fenofibrate. PMID:26834471

  13. Solubility of drugs in aqueous polymeric solution: effect of ovalbumin on microencapsulation process.

    Science.gov (United States)

    Aziz, Hesham Abdul; Tan, Yvonne Tze Fung; Peh, Kok Khiang

    2012-03-01

    Microencapsulation of water-soluble drugs using coacervation-phase separation method is very challenging, as these drugs partitioned into the aqueous polymeric solution, resulting in poor drug entrapment. For evaluating the effect of ovalbumin on the microencapsulation of drugs with different solubility, pseudoephedrine HCl, verapamil HCl, propranolol HCl, paracetamol, and curcuminoid were used. In addition, drug mixtures comprising of paracetamol and pseudoephedrine HCl were also studied. The morphology, encapsulation efficiency, particle size, and in vitro release profile were investigated. The results showed that the solubility of the drug determined the ratio of ovalbumin to be used for successful microencapsulation. The optimum ratios of drug, ovalbumin, and gelatin for water-soluble (pseudoephedrine HCl, verapamil HCl, and propranolol HCl), sparingly water-soluble (paracetamol), and water-insoluble (curcuminoid) drugs were found to be 1:1:2, 2:3:5, and 1:3:4. As for the drug mixture, the optimum ratio of drug, ovalbumin, and gelatin was 2:3:5. Encapsulated particles prepared at the optimum ratios showed high yield, drug loading, entrapment efficiency, and sustained release profiles. The solubility of drug affected the particle size of the encapsulated particle. Highly soluble drugs resulted in smaller particle size. In conclusion, addition of ovalbumin circumvented the partitioning effect, leading to the successful microencapsulation of water-soluble drugs.

  14. Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate

    Directory of Open Access Journals (Sweden)

    Yousaf AM

    2016-01-01

    Full Text Available Abid Mehmood Yousaf,1,2 Omer Mustapha,1 Dong Wuk Kim,1 Dong Shik Kim,1 Kyeong Soo Kim,1 Sung Giu Jin,1 Chul Soon Yong,3 Yu Seok Youn,4 Yu-Kyoung Oh,5 Jong Oh Kim,3 Han-Gon Choi1 1College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi, South Korea; 2Faculty of Pharmacy, University of Central Punjab, Johar, Lahore, Pakistan; 3College of Pharmacy, Yeungnam University, Gyongsan, North Gyeongsang, 4School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi, 5College of Pharmacy, Seoul National University, Seoul, South Korea Purpose: The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate.Methods: Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP and Labrafil® M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion.Results: All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1

  15. Water-soluble polymers for recovery of metal ions from aqueous streams

    Science.gov (United States)

    Smith, Barbara F.; Robison, Thomas W.

    1998-01-01

    A process of selectively separating a target metal contained in an aqueous solution by contacting the aqueous solution containing a target metal with an aqueous solution including a water-soluble polymer capable of binding with the target metal for sufficient time whereby a water-soluble polymer-target metal complex is formed, and, separating the solution including the water-soluble polymer-target metal complex from the solution is disclosed.

  16. Highly aqueous soluble CaF2:Ce/Tb nanocrystals: effect of surface functionalization on structural, optical band gap, and photoluminescence properties.

    Science.gov (United States)

    Ansari, Anees A; Parchur, Abdul K; Kumar, Brijesh; Rai, S B

    2016-12-01

    metal complex decomposition rout shows high dispersibility in aqueous solvents with enhanced photoluminescence. The epitaxial growth of inert CaF2 shell and further amorphous silica, respectively, enhanced their optical and luminescence properties, which is highly usable for luminescent biolabeling, and optical bioprobe etc.

  17. Density, Viscosity, Solubility, and Diffusivity of N2O in Aqueous Amino Acid Salt Solutions

    NARCIS (Netherlands)

    Kumar, P. Senthil; Hogendoorn, J.A.; Feron, P.H.M.; Versteeg, G.F.

    2001-01-01

    Solubility and diffusivity of N2O in aqueous solutions of potassium taurate are reported over a wide range of concentration and temperature. Also, the solubility of N2O in aqueous potassium glycinate solution is reported at 295 K. The ion specific constants are reported for taurate and glycinate ani

  18. Effect of biosurfactants on the aqueous solubility of PCE and TCE.

    Science.gov (United States)

    Albino, John D; Nambi, Indumathi M

    2009-12-01

    The effect of biosurfactants on the solubility of tetrachloroethylene (PCE) and trichloroethylene (TCE) was studied in batch experiments pertaining to their use for solubilization and mobilization of such contaminants in surfactant enhanced aquifer remediation. Biosurfactants, rhamnolipid and surfactin used in solubility studies were synthesized in our laboratory by Pseudomonas aeruginosa (MTCC 2297) and Bacillus subtilis (MTCC 2423), respectively. The efficiency of the biosurfactants in solubilizing the chlorinated solvents was compared to that of synthetic surfactants. The Weight Solubilization Ratio (WSR) values for solubilization of PCE and TCE by biosurfactants were very high compared to the values obtained for synthetic surfactants. Surfactin proved to be a better surfactant over rhamnolipid. The WSR of surfactin on solubilization of PCE and TCE were 3.83 and 12.5, respectively, whereas the values obtained for rhamnolipid were 2.06 and 8.36. The solubility of the chlorinated solvents by biosurfactants was considerably affected by the changes in pH. The aqueous solubility of PCE and TCE increased tremendously with decrease in pH. The solubility of biosurfactants was observed to decrease with the pH, favoring partitioning of surfactants into the chlorinated solvents in significant amounts at lower pH. The excessive accumulation of biosurfactants at the interface facilitated interfacial tension reductions resulting in higher solubility of the chlorinated solvents at pH less than 7.

  19. Soluble, Exfoliated Two-Dimensional Nanosheets as Excellent Aqueous Lubricants.

    Science.gov (United States)

    Zhang, Wenling; Cao, Yanlin; Tian, Pengyi; Guo, Fei; Tian, Yu; Zheng, Wen; Ji, Xuqiang; Liu, Jingquan

    2016-11-30

    Dispersion in water of two-dimensional (2D) nanosheets is conducive to their practical applications in fundamental science communities due to their abundance, low cost, and ecofriendliness. However, it is difficult to achieve stable aqueous 2D material suspensions because of the intrinsic hydrophobic properties of the layered materials. Here, we report an effective and economic way of producing various 2D nanosheets (h-BN, MoS2, MoSe2, WS2, and graphene) as aqueous dispersions using carbon quantum dots (CQDs) as exfoliation agents and stabilizers. The dispersion was prepared through a liquid phase exfoliation. The as-synthesized stable 2D nanosheets based dispersions were characterized by UV-vis, HRTEM, AFM, Raman, XPS, and XRD. The solutions based on CQD decorated 2D nanosheets were utilized as aqueous lubricants, which realized a friction coefficient as low as 0.02 and even achieved a superlubricity under certain working conditions. The excellent lubricating properties were attributed to the synergetic effects of the 2D nanosheets and CQDs, such as good dispersion stability and easy-sliding interlayer structure. This work thus proposes a novel strategy for the design and preparation of high-performance water based green lubricants.

  20. Aqueous solubility of a simple (single-carbon) organic molecule as a function of its size & dipole moment.

    Science.gov (United States)

    Al-Malah, Kamal I

    2011-05-01

    The aqueous solubility of a single-carbon organic molecule as a function of its size & dipole moment was investigated. The molecular dipole moment was chosen to represent the polar character of a poly-atomic molecule. It is hypothesized here that at a given pH, temperature, and pressure, the solubility of a single-carbon organic molecule in water will be a function of its polar character; namely, dipole moment and of its molecular size. Different forms of the solubility function were tested; it was found that the solubility model, given by Eq. 1, which is based on the polar character and the molecular volume, adequately described the aqueous solubility of single-carbon organic moieties. The aqueous solubility of single-carbon organic solutes exhibits maximum at the condition of high polar character (large dipole moment) and low molecular volume. The general trend of the solubility of single-carbon organic solutes, based on the proposed model (Eq. 1) could be explained in terms of the trade-off between the driving force (degree of polar character of the solute) for solubilization versus the resistance to be solubilized as a result of the entropic effects which increase with increasing molecular volume of the organic moiety.

  1. Solubility of Carbon Dioxide and Hydrogen Sulfide in Aqueous N-Methyldiethanolamine Solutions

    OpenAIRE

    Huttenhuis, P. J. G.; Agrawal, N.J.; Versteeg, G. F.

    2009-01-01

    In this work, 72 new experimental solubility data points for H(2)S and CO(2) mixtures in aqueous N-methyldiethanol amine (MDEA) solutions at different methane partial pressures (up to 69 bara) are presented. They are correlated using an electrolyte equation of state (E-EOS) thermodynamic model. This model has already been used to estimate the CO(2) solubility in aqueous MDEA (Huttenhuis et al. Fluid Phase Equilib. 2008, 264, 99-112) and the H(2)S solubility in aqueous MDEA (Huttenhuis et al. ...

  2. Aqueous coating dispersion (pseudolatex) of zein improves formulation of sustained-release tablets containing very water-soluble drug.

    Science.gov (United States)

    Li, X N; Guo, H X; Heinamaki, J

    2010-05-01

    Zein is an alcohol soluble protein of corn origin that exhibits hydrophobic properties. Pseudolatexes are colloidal dispersions containing spherical solid or semisolid particles less than 1 microm in diameter and can be prepared from any existing thermoplastic water-insoluble polymer. The novel plasticized film-coating pseudolatex of zein was studied in formulation of sustained-release tablets containing very water-soluble drug. Film formation of plasticized aqueous dispersion was compared with film forming properties of plasticized organic solvent system (ethanol) of zein. The water vapor permeability (WVP), water uptake and erosion, and moisture sorption were evaluated with free films. The tablets containing metoprolol tartrate as a model drug were used in pan-coating experiments. Aqueous film coatings plasticized with PEG 400 exhibited very low water uptake. No significant difference in WVP, moisture sorption and erosion were found between aqueous films and organic solvent-based films of zein plasticized with PEG 400. The atomic force microscopy (AFM) images on microstructure of films showed that colloidal particle size of zein in the aqueous films was smaller than that observed in the solvent-based films. In addition, the aqueous-based films were more compact and smoother than the respective solvent-based films. The aqueous zein-coated tablets containing very water-soluble drug (metoprolol tartrate) exhibited clear sustained-release dissolution profiles in vitro, while the respective solvent-based film-coated tablets showed much faster drug release. Furthermore, aqueous zein-coated tablets had lower water absorption at high humidity conditions. In conclusion, the plasticized aqueous dispersion (pseudolatex) of zein can be used for moisture resistant film coating of sustained-release tablets containing very water-soluble drug.

  3. The solubility of toluene in aqueous salt solutions.

    Science.gov (United States)

    Poulson, S; Harrington, R; Drever, J

    1999-03-01

    The solubility of toluene has been measured in distilled water, and in various inorganic salt solutions. Values of the Setschenow constant, K(S), which quantify toluene solubility versus salt concentration, have been determined for each salt. Values of K(S) are compared to the activity of water for the salt solutions. Data from this study, consistent with earlier data, suggests that the effects of salts upon toluene solubility are non-additive. This contrasts the additive behavior of inorganic salts upon the solubility of nonpolar organic compounds, such as benzene and naphthalene, reported in the literature. Specific interaction between slightly polar toluene and ions in solution is suggested as a possible explanation for the non-additive effect of salts on the solubility of toluene.

  4. Study on Mixed Solvency Concept in Formulation Development of Aqueous Injection of Poorly Water Soluble Drug

    Directory of Open Access Journals (Sweden)

    Shailendra Singh Solanki

    2013-01-01

    Full Text Available In the present investigation, mixed-solvency approach has been applied for the enhancement of aqueous solubility of a poorly water- soluble drug, zaltoprofen (selected as a model drug, by making blends (keeping total concentrations 40% w/v, constant of selected water-soluble substances from among the hydrotropes (urea, sodium benzoate, sodium citrate, nicotinamide; water-soluble solids (PEG-4000, PEG-6000; and co-solvents (propylene glycol, glycerine, PEG-200, PEG-400, PEG-600. Aqueous solubility of drug in case of selected blends (12 blends ranged from 9.091 ± 0.011 mg/ml–43.055 ± 0.14 mg/ml (as compared to the solubility in distilled water 0.072 ± 0.012 mg/ml. The enhancement in the solubility of drug in a mixed solvent containing 10% sodium citrate, 5% sodium benzoate and 25 % S cosolvent (25% S cosolvent contains PEG200, PEG 400, PEG600, Glycerine and Propylene glycol was more than 600 fold. This proved a synergistic enhancement in solubility of a poorly water-soluble drug due to mixed cosolvent effect. Each solubilized product was characterized by ultraviolet and infrared techniques. Various properties of solution such as pH, viscosity, specific gravity and surface tension were studied. The developed formulation was studied for physical and chemical stability. This mixed solvency shall prove definitely a boon for pharmaceutical industries for the development of dosage form of poorly water soluble drugs.

  5. Low aqueous solubility of 11-cis-retinal limits the rate of pigment formation and dark adaptation in salamander rods.

    Science.gov (United States)

    Frederiksen, Rikard; Boyer, Nicholas P; Nickle, Benjamin; Chakrabarti, Kalyan S; Koutalos, Yiannis; Crouch, Rosalie K; Oprian, Daniel; Cornwall, M Carter

    2012-06-01

    We report experiments designed to test the hypothesis that the aqueous solubility of 11-cis-retinoids plays a significant role in the rate of visual pigment regeneration. Therefore, we have compared the aqueous solubility and the partition coefficients in photoreceptor membranes of native 11-cis-retinal and an analogue retinoid, 11-cis 4-OH retinal, which has a significantly higher solubility in aqueous medium. We have then correlated these parameters with the rates of pigment regeneration and sensitivity recovery that are observed when bleached intact salamander rod photoreceptors are treated with physiological solutions containing these retinoids. We report the following results: (a) 11-cis 4-OH retinal is more soluble in aqueous buffer than 11-cis-retinal. (b) Both 11-cis-retinal and 11-cis 4-OH retinal have extremely high partition coefficients in photoreceptor membranes, though the partition coefficient of 11-cis-retinal is roughly 50-fold greater than that of 11-cis 4-OH retinal. (c) Intact bleached isolated rods treated with solutions containing equimolar amounts of 11-cis-retinal or 11-cis 4-OH retinal form functional visual pigments that promote full recovery of dark current, sensitivity, and response kinetics. However, rods treated with 11-cis 4-OH retinal regenerated on average fivefold faster than rods treated with 11-cis-retinal. (d) Pigment regeneration from recombinant and wild-type opsin in solution is slower when treated with 11-cis 4-OH retinal than with 11-cis-retinal. Based on these observations, we propose a model in which aqueous solubility of cis-retinoids within the photoreceptor cytosol can place a limit on the rate of visual pigment regeneration in vertebrate photoreceptors. We conclude that the cytosolic gap between the plasma membrane and the disk membranes presents a bottleneck for retinoid flux that results in slowed pigment regeneration and dark adaptation in rod photoreceptors.

  6. Organic Redox Species in Aqueous Flow Batteries: Redox Potentials, Chemical Stability and Solubility

    Science.gov (United States)

    Wedege, Kristina; Dražević, Emil; Konya, Denes; Bentien, Anders

    2016-12-01

    Organic molecules are currently investigated as redox species for aqueous low-cost redox flow batteries (RFBs). The envisioned features of using organic redox species are low cost and increased flexibility with respect to tailoring redox potential and solubility from molecular engineering of side groups on the organic redox-active species. In this paper 33, mainly quinone-based, compounds are studied experimentially in terms of pH dependent redox potential, solubility and stability, combined with single cell battery RFB tests on selected redox pairs. Data shows that both the solubility and redox potential are determined by the position of the side groups and only to a small extent by the number of side groups. Additionally, the chemical stability and possible degradation mechanisms leading to capacity loss over time are discussed. The main challenge for the development of all-organic RFBs is to identify a redox pair for the positive side with sufficiently high stability and redox potential that enables battery cell potentials above 1 V.

  7. Solubility behavior and prediction for antihelmintics at several temperatures in aqueous and nonaqueous mixtures.

    Science.gov (United States)

    Bustamante, Pilar; Muela, Susana; Escalera, Begoña; Peña, Angeles

    2010-05-01

    A model based on solubility parameters is proposed to predict the solubility curves of antihelmintic drugs at several temperatures, including aqueous and non-aqueous mixtures. The solubility of the drugs was measured in ethanol-water and ethanol-ethyl acetate mixtures at 15-35 degrees C (mebendazole) and at 25 degrees C (thiabendazole and metronidazole). The solid phases were analyzed by differential scanning calorimerty. The polymorphic form A of mebendazole was also characterized from infrared spectroscopy. Markedly different solubility profile shapes were obtained against the solubility parameter of the mixtures: two symmetrical peaks (metronidazole), two maxima of different height (mebendazole) and a single peak (thiabendazole). The solubility parameter of the drugs was related to the co-solvent action of both mixtures and to the solubility peaks. The single equation proposed was able to predict solubility profiles of different shape, including both mixtures and all temperatures, providing reasonable physical meaning for the regression coefficients. The model was successfully tested for its predictive capability using a limited number of experimental data. More than 100 solubilities were predicted at several temperatures using 20 data point for each drug.

  8. Water-soluble diphosphadiazacyclooctanes as ligands for aqueous organometallic catalysis

    KAUST Repository

    Boulanger, Jérôme

    2012-12-01

    Two new water-soluble diphosphacyclooctanes been synthesized and characterized by NMR and surface tension measurements. Both phosphanes proved to coordinate rhodium in a very selective way as well-defined bidentates were obtained. When used in Rh-catalyzed hydroformylation of terminal alkenes, both ligands positively impacted the reaction chemoselectivity. © 2012 Elsevier B.V.

  9. PAH toxicity at aqueous solubility in the fish embryo test with Danio rerio using passive dosing

    DEFF Research Database (Denmark)

    Fernqvist, Margit; Mayer, Philipp; Smith, Kilian

    2014-01-01

    As part of the risk assessment process within REACh, prior to manufacturing and distribution of chemical substances their (eco)toxicological impacts have to be investigated. The fish embryo toxicity test (FET) with the zebrafish Danio rerio has gained a high significance as an in vitro alternative...... to animal testing in (eco)toxicology. However, for hydrophobic organic chemicals it remains a technical challenge to ensure constant freely dissolved concentration at the maximum exposure level during such biotests. Passive dosing with PDMS silicone was thus applied to control the freely dissolved...... further data to support the close relationship between the chemical activity and the toxicity of hydrophobic organic compounds. Passive dosing from PDMS silicone enabled reliable toxicity testing of (highly) hydrophobic substances at aqueous solubility, providing a practical way to control toxicity...

  10. Investigations on the 4-Quinolone-3-carboxylic Acid Motif. 7. Synthesis and Pharmacological Evaluation of 4-Quinolone-3-carboxamides and 4-Hydroxy-2-quinolone-3-carboxamides as High Affinity Cannabinoid Receptor 2 (CB2R) Ligands with Improved Aqueous Solubility.

    Science.gov (United States)

    Mugnaini, Claudia; Brizzi, Antonella; Ligresti, Alessia; Allarà, Marco; Lamponi, Stefania; Vacondio, Federica; Silva, Claudia; Mor, Marco; Di Marzo, Vincenzo; Corelli, Federico

    2016-02-11

    4-Quinolone-3-carboxamide derivatives have long been recognized as potent and selective cannabinoid type-2 receptor (CB2R) ligands. With the aim to improve their physicochemical properties, basically aqueous solubility, two different approaches were followed, entailing the substitution of the alkyl chain with a basic replacement or scaffold modification to 4-hydroxy-2-quinolone structure. According to the first approach, compound 6d was obtained, showing slightly reduced receptor affinity (K(i) = 60 nM) compared to the lead compound 4 (0.8 nM) but greatly enhanced solubility (400-3400 times depending on the pH of the medium). On the other hand, shifting from 4-quinolone to 4-hydroxy-2-quinolone structure enabled the discovery of a novel class of CB2R ligands, such as 7b and 7c, characterized by K(i) 1300. At pH 7.4, compound 7c resulted by 100-fold more soluble than 4.

  11. One-pot synthesis and control of aqueous soluble and organic soluble carbon dots from a designable waterborne polyurethane emulsion

    Science.gov (United States)

    Gu, Jiangjiang; Hu, Donghua; Huang, Jin; Huang, Xin; Zhang, Qiuhong; Jia, Xudong; Xi, Kai

    2016-02-01

    Carbon dots (CDs) have a wide range of applications and have drawn great interest in the recent decade. The fabrication and control of CDs with different solubilities are still urgent problems for their practical use. In this paper, aqueous soluble and organic soluble CDs (ACDs, OCDs) were produced by one-pot hydrothermal treatment of a designable waterborne polyurethane (WPU) emulsion. The difference in the solubility and fluorescence of these two kinds of CDs was attributed to the various functional groups on the surface, which were derived from the different segment fragments formed by hydrothermal treatment of a block polymer. It was found that the yields of the ACDs and OCDs could be regulated by means of selecting different soft segments in WPU. The more hydrophobic soft segments could result in an increase of the OCDs and a decrease of the ACDs. While the soft segments were hydrophilic or hydrolysable under hydrothermal conditions, only ACDs were obtained. The ACDs had good fluorescence and showed low cytotoxicity for use in multicolour bio-imaging. The OCDs processed good solubility in a wide range of organic solvents and were suitable for preparing fluorescent composite films with polymers.Carbon dots (CDs) have a wide range of applications and have drawn great interest in the recent decade. The fabrication and control of CDs with different solubilities are still urgent problems for their practical use. In this paper, aqueous soluble and organic soluble CDs (ACDs, OCDs) were produced by one-pot hydrothermal treatment of a designable waterborne polyurethane (WPU) emulsion. The difference in the solubility and fluorescence of these two kinds of CDs was attributed to the various functional groups on the surface, which were derived from the different segment fragments formed by hydrothermal treatment of a block polymer. It was found that the yields of the ACDs and OCDs could be regulated by means of selecting different soft segments in WPU. The more

  12. The solubility of hydrogen sulfide in aqueous N-methyldiethanolamine solutions

    OpenAIRE

    Huttenhuis, P. J. G.; Agrawal, N.J.; Versteeg, G. F.

    2008-01-01

    In this work the electrolyte equation of state as developed previously for the system MDEA-H2O-CO2-CH4 was further developed for the system MDEA-H2O-H2S-CH4. With this thermodynamic equilibrium model the total solubility of hydrogen sulfide and the speciation in aqueous solutions of N-methyldiethanolamine can be described quantitatively. The model results were compared to experimental H2S solubility data in aqueous MDEA in absence and presence of methane respectively. The application of equat...

  13. Solubility of diazepam and prazepam in aqueous non-ionic surfactants.

    Science.gov (United States)

    Moro, M E; Velazquez, M M; Cachaza, J M; Rodriguez, L J

    1986-04-01

    The solubility of diazepam and prazepam in aqueous polyoxyethylen-10-dodecanol, polyoxyethylen-23-dodecanol and polyoxyethylen-20-hexadecanol, has been determined at 25.0 degrees C. Diazepam seems to achieve a higher micellar penetration than prazepam, in spite of an expected smaller hydrophobic character. Thermodynamic interpretation of the micellar solutions is carried out using the regular solutions approach. A surfactant-independent relation between solubilities of both drugs has been derived.

  14. The amorphous solid dispersion of the poorly soluble ABT-102 forms nano/microparticulate structures in aqueous medium: impact on solubility

    Directory of Open Access Journals (Sweden)

    Frank KJ

    2012-11-01

    Full Text Available Kerstin J Frank,1,3 Ulrich Westedt,2 Karin M Rosenblatt,2 Peter Hölig,2 Jörg Rosenberg,2 Markus Mägerlein,2 Gert Fricker,3 Martin Brandl11Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark; 2Abbott GmbH and Co. KG, Ludwigshafen, Germany; 3Department of Pharmaceutical Technology, University of Heidelberg, Heidelberg, GermanyAbstract: Amorphous solid dispersions (ASDs are a promising formulation approach for poorly soluble active pharmaceutical ingredients (APIs, because they ideally enhance both dissolution rate and solubility. However, the mechanism behind this is not understood in detail. In the present study, we investigated the supramolecular and the nano/microparticulate structures that emerge spontaneously upon dispersion of an ASD in aqueous medium and elucidated their influence on solubility. The ASD, prepared by hot melt extrusion, contained the poorly soluble ABT-102 (solubility in buffer, 0.05 µg/mL, a hydrophilic polymer, and three surfactants. The apparent solubility of ABT-102 from the ASD-formulation was enhanced up to 200 times in comparison to crystalline ABT-102. At the same time, the molecular solubility, as assessed by inverse equilibrium dialysis, was enhanced two times. Asymmetrical flow field-flow fractionation in combination with a multiangle light-scattering detector, an ultraviolet detector, and a refractometer enabled us to separate and identify the various supramolecular assemblies that were present in the aqueous dispersions of the API-free ASD (placebo and of binary/ternary blends of the ingredients. Thus, the supramolecular assemblies with a molar mass between 20,000 and 90,000 could be assigned to the polyvinylpyrrolidone/vinyl acetate 64, while two other kinds of assemblies were assigned to different surfactant assemblies (micelles. The amount of ABT-102 remaining associated with each of the assemblies upon fractionation was quantified offline with high

  15. Buckminsterfullerene's (C60) octanol-water partition coefficient (Kow) and aqueous solubility.

    Science.gov (United States)

    Jafvert, Chad T; Kulkarni, Pradnya P

    2008-08-15

    To assess the risk and fate of fullerene C60 in the environment, its water solubility and partition coefficients in various systems are useful. In this study, the log Kow of C60 was measured to be 6.67, and the toluene-water partition coefficient was measured at log Ktw = 8.44. From these values and the respective solubilities of C60 in water-saturated octanol and water-saturated toluene, C60's aqueous solubility was calculated at 7.96 ng/L(1.11 x 10(-11) M) for the organic solvent-saturated aqueous phase. Additionally, the solubility of C60 was measured in mixtures of ethanol-water and tetrahydrofuran-water and modeled with Wohl's equation to confirm the accuracy of the calculated solubility value. Results of a generator column experiment strongly support the hypothesis that clusters form at aqueous concentrations below or near this calculated solubility. The Kow value is compared to those of other hydrophobic organic compounds, and bioconcentration factors for C60 were estimated on the basis of Kow.

  16. Solubility Behaviour of Cellulose in a Sodium Hydrate/Urea/Thiourea Aqueous Solvent

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shuai; CHENG Feng-wei; LI Fa-xue; YU Jian-yong; GU Li-xia

    2008-01-01

    Cellulose pulps were directly dissolved in a green solvent of sodium hydrate/urea/thiourea/water with different composition for the purpose to prepare new regenerated cellulose fibers or films. The results showed that the highest solubility of cellulose in the solvent with the composition of 8/8/6.5/77.5. The results revealed that the pulp feeding sequence, stirring rate, pre-treatment of pulp and pulp size affected the cellulose concentration in the green solvent. Accordingly, the more effective dissolution method was proposed in order to get higher concentration of cellulose. Furthermore, the properties of solution prepared by different kinds of pulps in the solvent were investigated by ARES rheometer. Rheological analyses indicated that all cellulose aqueous solutions in their high concentration were pseudoplastic fluids and sensitive to temperature and tended to transform to gel when temperature increased.

  17. PAH toxicity at aqueous solubility in the fish embryo test with Danio rerio using passive dosing

    DEFF Research Database (Denmark)

    Seiler, Thomas-Benjamin; Best, Nina; Fernqvist, Margit Møller

    2014-01-01

    to animal testing in (eco)toxicology. However, for hydrophobic organic chemicals it remains a technical challenge to ensure constant freely dissolved concentration at the maximum exposure level during such biotests. Passive dosing with PDMS silicone was thus applied to control the freely dissolved...... further data to support the close relationship between the chemical activity and the toxicity of hydrophobic organic compounds. Passive dosing from PDMS silicone enabled reliable toxicity testing of (highly) hydrophobic substances at aqueous solubility, providing a practical way to control toxicity...... without direct contact to the silicone surface showed similar mortalities as those exposed with direct contact to the silicone. Silicone oil overlaying the water phase as a novel passive dosing phase had no observable effects on the development of the fish embryos until hatching. This study provides...

  18. A model for estimating CO2 solubility in aqueous alkanolamines

    DEFF Research Database (Denmark)

    Gabrielsen, Jostein; Michelsen, Michael Locht; Stenby, Erling Halfdan

    2005-01-01

    Partial pressures of carbon dioxide (CO2) over aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), and N-methyldiethanolamine (MDEA) have been correlated using a simple approach where only one chemical equilibrium reaction is taken into account and assuming ideal gas and ideal liquid...... properties. The approach combines the Henry's law constant and the chemical reaction equilibrium constant for the formation of carbamate for primary and secondary alkanolamines (MEA, DEA) or bicarbonate for tertiary alkanolamines(MDEA), resulting in an explicit expression for calculating the partial pressure...

  19. A novel method for determining the solubility of small molecules in aqueous media and polymer solvent systems using solution calorimetry.

    Science.gov (United States)

    Fadda, Hala M; Chen, Xin; Aburub, Aktham; Mishra, Dinesh; Pinal, Rodolfo

    2014-07-01

    To explore the application of solution calorimetry for measuring drug solubility in experimentally challenging situations while providing additional information on the physical properties of the solute material. A semi-adiabatic solution calorimeter was used to measure the heat of dissolution of prednisolone and chlorpropamide in aqueous solvents and of griseofulvin and ritonavir in viscous solutions containing polyvinylpyrrolidone and N-ethylpyrrolidone. Dissolution end point was clearly ascertained when heat generation stopped. The heat of solution was a linear function of dissolved mass for all drugs (calorimetry offers a reliable method for measuring drug solubility in organic and aqueous solvents. The approach is complementary to the traditional shake-flask method, providing information on the solid properties of the solute. For highly viscous solutions, the calorimetric approach is advantageous.

  20. Asymmetric Transfer Hydrogenation of Prochiral Ketones in Aqueous Media with New Water-Soluble Chiral Vicinal Diamine as Ligand

    Institute of Scientific and Technical Information of China (English)

    ZHU Jin; MA Ya-Ping; LIU Hui; CHEN Li; CUI Xin; DENG Jin-Gen

    2003-01-01

    @@ As a consequence of the increasing demand for atom economy and environmental friendly methods, the water soluble ligands and their metal complexes are of great interest in catalytic synthesis because of simpler product sepa ration and the possibility of recycling. [1] Unique reactivity and selectivity are often observed in aqueous reactions. [2]Recently, we have developed a new water-soluble chiral vicinal diamine and synthesized its mono-N-tosylated derivative for the first time. The application of its mono-N-tosylated derivative in catalytic asymmetric transfer hydrogenation of prochiral ketones was examined in aqueous media. High activity (up to > 99 % conv. ) and good enatioselectivity ( up to 98% ee ) were achieved for most of prochiral aromatic ketones in organic solvent free system. [3

  1. Solubility of carbon dioxide and hydrogen sulfide in aqueous N-methyldiethanolamine solutions

    Energy Technology Data Exchange (ETDEWEB)

    Huttenhuis, P.J.G.; Agrawal, N.J.; Versteeg, G.F. [Procede Group BV, Enschede (Netherlands)

    2009-04-15

    In this work, 72 new experimental solubility data points for H{sub 2}S and CO{sub 2} mixtures in aqueous N-methyldiethanol amine (MDEA) solutions at different methane partial pressures (up to 69 bara) are presented. They are correlated using an electrolyte equation of state (E-EOS) thermodynamic model. This model has already been used to estimate the CO{sub 2} solubility in aqueous MDEA (Huttenhuis et al. Fluid Phase Equilib. 2008, 264, 99-112) and the H{sub 2}S solubility in aqueous MDEA (Huttenhuis et al. Int. J. Oil, Gas Coal Technol. 2008, 1, 399-424). Here, the model is further extended to predict the behavior of CO{sub 2} and H{sub 2}S when they are present simultaneously in aqueous MDEA. The application of an equation of state is a new development for this type of system, i.e., of acid-gas-amine systems. The molecular interactions are described by Schwarzentruber et al.'s modification of the Redlich-Kwong-Soave equation of state, with terms added to account for ionic interactions in the liquid phase. The model is used to describe acid-gas solubility data for the CO{sub 2}-H{sub 2}S-MDEA-H{sub 2}O system reported in the open literature and experimental data reported here for the CO{sub 2}-H{sub 2}S-MDEA-H{sub 2}O-CH{sub 4} system.

  2. The solubility of hydrogen sulfide in aqueous N-methyldiethanolamine solutions

    NARCIS (Netherlands)

    Huttenhuis, P.J.G.; Agrawal, N.J.; Versteeg, G.F.

    2008-01-01

    In this work the electrolyte equation of state as developed previously for the system MDEA-H2O-CO2-CH4 was further developed for the system MDEA-H2O-H2S-CH4. With this thermodynamic equilibrium model the total solubility of hydrogen sulfide and the speciation in aqueous solutions of N-methyldiethano

  3. Solubility of Carbon Dioxide and Hydrogen Sulfide in Aqueous N-Methyldiethanolamine Solutions

    NARCIS (Netherlands)

    Huttenhuis, P. J. G.; Agrawal, N. J.; Versteeg, G. F.

    2009-01-01

    In this work, 72 new experimental solubility data points for H(2)S and CO(2) mixtures in aqueous N-methyldiethanol amine (MDEA) solutions at different methane partial pressures (up to 69 bara) are presented. They are correlated using an electrolyte equation of state (E-EOS) thermodynamic model. This

  4. Activity-Based Approach for Teaching Aqueous Solubility, Energy, and Entropy

    Science.gov (United States)

    Eisen, Laura; Marano, Nadia; Glazier, Samantha

    2014-01-01

    We describe an activity-based approach for teaching aqueous solubility to introductory chemistry students that provides a more balanced presentation of the roles of energy and entropy in dissolution than is found in most general chemistry textbooks. In the first few activities, students observe that polar substances dissolve in water, whereas…

  5. Solubility of N2O in and density, viscosity, and surface tension of aqueous piperazine solutions

    NARCIS (Netherlands)

    Derks, P. W.; Hogendoorn, K. J.; Versteeg, G. F.

    2005-01-01

    The physical solubility of N2O in and the density and viscosity of aqueous piperazine solutions have been measured over a temperature range of (293.15 to 323.15) K for piperazine concentrations ranging from about (0.6 to 1.8) kmol·mr-3. Furthermore, the present study contains experimental surface

  6. Solubility of N2O in and density, viscosity, and surface tension of aqueous piperazine solutions

    NARCIS (Netherlands)

    Derks, P. W.; Hogendoorn, K. J.; Versteeg, G. F.

    2005-01-01

    The physical solubility of N2O in and the density and viscosity of aqueous piperazine solutions have been measured over a temperature range of (293.15 to 323.15) K for piperazine concentrations ranging from about (0.6 to 1.8) kmol·mr-3. Furthermore, the present study contains experimental surface t

  7. The solubility of ethane, propane, and carbon dioxide in aqueous solutions of sodium cumene sulfonate.

    Science.gov (United States)

    King, A D

    2004-05-01

    Measurements have been made to determine the solubilities of ethane, C2H6, propane, C3H8, and carbon dioxide, CO2, in aqueous solutions of sodium cumene sulfonate (NaCS) at 25 degrees C. The solubilities measured for each gas satisfy Henry's law at all concentrations of NaCS. The solubilities of C2H6 and C3H8 exhibit quite similar behavior with respect to added NaCS. The solubilities of these two gases are very low in pure water and are found to be nearly independent of NaCS concentration over a concentration range of 0-0.4 mol NaCS/kg H2O. At intermediate concentrations of NaCS, the solubilities of C2H6 and C3H8 exhibit a gradual increase with added NaCS concentrations ranging from 0.4 to 2.0 mol NaCS/kg H2O. At NaCS concentrations greater than 2.0 mol NaCS/kg H2O, the solubilities of these two gases increase with added NaCS in an approximately linear manner, with the solubility of C3H8 increasing more rapidly than that for C2H6 (by a factor of approximately 2.5). CO2 is much more soluble in pure water than the hydrocarbon gases and exhibits markedly different behavior with respect to added NaCS. The solubility of CO2 decreases with added NaCS over a concentration range of 0-0.9 mol NaCS/kg H2O, passes through a minimum at a concentration of approximately 1.0 mol NaCS/kg H2O, and then increases with added NaCS at higher NaCS concentrations in a manner similar to that observed with C2H6 and C3H8. The trends in solubility observed for these three gases dissolved in aqueous solutions of NaCS resemble those found previously with aqueous solutions of ordinary surfactants. The solubility data measured for these three gases can be interpreted surprisingly well in terms of the mass-action model for micellization, in which salting-out effects due to monomer salt ions suppress gas solubility at low NaCS concentrations and gas solubilization by small micelles of NaCS acts to enhance gas solubility at the higher NaCS concentrations.

  8. Prediction of pH-dependent aqueous solubility of Histone Deacetylase (HDAC) inhibitors

    DEFF Research Database (Denmark)

    Kouskoumvekaki, Irene; Hansen, Niclas Tue; Bjorkling, F.

    2008-01-01

    Recently we developed a model for prediction of pH-dependent aqueous solubility of drugs and drug like molecules. In the present work, the model was applied on a series of novel Histone Deacetylases (HDAC) inhibitors discovered at TopoTarget. The applicability of our model was evaluated on the se......Recently we developed a model for prediction of pH-dependent aqueous solubility of drugs and drug like molecules. In the present work, the model was applied on a series of novel Histone Deacetylases (HDAC) inhibitors discovered at TopoTarget. The applicability of our model was evaluated...... can develop models that are more accurate in predicting differences in the solubility of structurally very similar compounds than models that have been trained on structurally unbiased, diverse data sets. Such 'tailor-made' models have the potential to become trustworthy enough to replace time...

  9. 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.

  10. Thermodynamic model for the solubility of BaSeO4(cr) in the aqueous Ba2+-SeO42--Na+-H+-OH--H2O system: Extending to high selenate concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Dhanpat; Felmy, Andrew R.; Moore, Dean A.; Kitamura, Akira; Yoshikawa, Hideki; Doi, Reisuke; Yoshida, Yasushi

    2014-09-15

    The solubility of Ba(SeO4, SO4) precipitates was determined as a function of the BaSeO4 mole fractions, ranging from 0.0015 to 0.3830, and time with an equilibration period extending to as long as 302 days. Equilibrium/steady state conditions in this system are reached in ≤ 65 days. Pitzer’s ion interaction model was used to calculate solid and aqueous phase activity coefficients. Thermodynamic analyses showed that the data do not satisfy Gibbs-Duhem equation, thereby demonstrating that a single-solid solution phase does not control both the selenate and sulfate concentrations. Our extensive data with log10 [Ba]) ranging from -3.6 to -5.9 mol.kg-1, log10 [SeO4]) ranging from -3.6 to -5.2 mol.kg-1, and log10 [SO4] ranging from -4.0 to -5.3 mol.kg-1 can be explained with the formation of an ideal BaSeO4 solid solution phase that controls the selenium concentrations and a slightly disordered/less-crystalline BaSO4(s) (log10 K0sp = -9.5 instead of -10.05 for barite) that controls the sulfate concentrations. In these experiments the BaSO4 component of the solid solution phase never reaches thermodynamic equilibrium with the aqueous phase. Thermodynamic interpretations of the data show that both the ideal BaSeO4 solid solution phase and less-crystalline BaSO4(s) phase are in equilibrium with each other in the entire range of BaSeO4 mole fractions investigated in this study.

  11. How does beta-cyclodextrin affect oxygen solubility in aqueous solutions of sodium perfluoroheptanoate?

    Science.gov (United States)

    Dias, A M A; Andrade-Dias, C; Lima, S; Coutinho, J A P; Teixeira-Dias, J J C; Marrucho, I M

    2006-11-15

    The solubility of oxygen in aqueous solutions of sodium perfluoroheptanoate (NaPFHept) at different concentrations was measured at 310.15 K with an apparatus based on the saturation method. The effect of adding beta-cyclodextrin (betaCD) on the solubility of oxygen was also studied. Conductimetry measurements showed that the presence of betaCD in aqueous solutions of NaPFHept increases its critical micellar concentration (CMC). In the presence of betaCD (15 mM), the characteristic minimum of oxygen solubility observed at the CMC is shifted from 83 to 114 mM, and the curvature at the minimum is reduced to 64% of the value in the absence of betaCD. Chemical shift changes for the H5 protons of betaCD, recorded as functions of the initial concentration of NaPFHept, point to the formation of a relatively strong 1:1 inclusion in betaCD of the perfluoroheptanoate anion. Hence, it is suggest that the effect of adding betaCD on the solubility of oxygen cannot be accounted for only by the perfluoroheptanoate anion inclusion in betaCD, but has to be ascribed to the direct influence of this inclusion complex on disrupting the aggregation process reducing the increase of oxygen solubility after the CMC value.

  12. High throughput UV method for the estimation of thermodynamic solubility and the determination of the solubility in biorelevant media.

    Science.gov (United States)

    Bard, Bruno; Martel, Sophie; Carrupt, Pierre-Alain

    2008-03-03

    The growing interest for high quality solubility data in the early stages of drug discovery suggested a detailed optimization of experimental conditions for a 96-well HTS UV method in order to obtain solubility values close to thermodynamic solubility measured by shake-flask method. Results have shown that solubility data obtained by the HTS approach were highly dependent on shaking intensity and incubation times due to the formation of supersaturated solutions resulting from the dilution of DMSO stock solutions in aqueous buffer. Thus, careful experimental set-up was developed to improve the quality and the reproducibility of the HTS method. Moreover, the early qualitative prediction of bioavailability and absorption of orally administered drugs require more and more biorelevant solubility values in drug discovery programs. Thus, the optimized HTS method was also adapted to measure solubility directly in FaSSIF and FeSSIF media. The versatile HTS UV approach presented in this paper provides a unique and reliable way to determine solubility in various experimental conditions.

  13. An experimental study of the solubility and speciation of niobium in fluoride-bearing aqueous solutions at elevated temperature

    Science.gov (United States)

    Timofeev, A.; Migdisov, Art. A.; Williams-Jones, A. E.

    2015-06-01

    The solubility of Nb2O5 and the speciation of niobium in HF-bearing aqueous solutions have been determined at temperatures of 150, 200, and 250 °C and saturated water pressure. At a pH of ∼2 and at low HF concentration, niobium is transported primarily as the species Nb(OH)4+ and at high HF concentration, as the species NbF2(OH)3°. Equilibrium constants for the formation of Nb(OH)4+ range from -11.23 ± 0.26 to -10.86 ± 0.24 and for the formation of NbF2(OH)3° from -3.84 ± 0.20 to -5.08 ± 0.42, at 150 and 250 °C. The results of this study show that the solubility of Nb2O5 (solid) in aqueous fluids increases with increasing HF concentration, but is not strongly affected by temperature. The influence of pH is variable; at low pH and HF concentration, a decrease in pH increases the solubility of Nb2O5 (solid). At higher pH, the reverse may be true. Modeling of the transport and deposition of niobium suggests that simple mixing with a brine is not an effective method for removing niobium from solution. By contrast, interaction of an acidic fluid with carbonate rock results in a rapid reduction in the capacity of the fluid to mobilize niobium.

  14. Solubility Measurements and Modeling of Zinc, Lead and Iron Sulfides at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Carolina Figueroa Murcia, Diana; Fosbøl, Philip Loldrup; Thomsen, Kaj

    Solubility measurements of sulfides in aqueous solutions are necessary to understand the behaviour of these scaling minerals in geothermal and oil reservoirs. The low solubility levels of Zinc Sulfide (ZnS), Lead Sulfide (PbS) and Iron Sulfide (FeS) make the solubility measurements a challenging...... task. Consequently existing data are rare and scattered. The aim of this work is to develop a reliable experimental procedure and to measure solubility of sulfides at high temperature and pressures. Additionally the experimental data are used for estimation of the solid-liquid equilibrium using...... oxygen atmosphere to avoid the risk of oxidation of sulfide minerals. The solution is kept in an equilibrium cell at constant temperature and pressure with continuous stirring. The concentration of Zn2+, Pb2+, Fe2+ and S2- are measured using Inductively Coupled Plasma Optical Emission spectrometry (ICP...

  15. Facile Size-controllable Aqueous Synthesis of Water Soluble CdTe/Cd(OH)2 Core/Shell Nanoparticles with Tunable Optical Property, High Quantum Yield and Good Stability

    Institute of Scientific and Technical Information of China (English)

    CAI,Zhao-Xia; CHEN,Ying-Jun; YAN,Xiu-Ping

    2008-01-01

    A facile procedure was developed to prepare size-tunable and water soluble CdTe/Cd(OH)2 core/shell nanopar-ticles with high quantum yields and good stability using inexpensive inorganic precursors (CdCl2 and elemental Te). The emission colors of the prepared CdTe/Cd(OH)2 core/shell nanoparticles can be readily tuned from cyan to salmon pink by varying incubation time to control the growth of the Cd(OH)2 shell onto the CdTe nanoparticles. The CdTe/Cd(OH)2 core/shell nanoparticles were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, X-ray powder diffraction spectrometry, photoluminescence and UV-Vis spec-trometry. The good water-soluble nature of the CdTe/Cd(OH)2 core/shell nanoparticles offers great potentiality for their bio-labeling application. This approach is simple, mild and readily scaled up, affording a simple way for synthesis of size-tunable inorganic metal hydroxide capped core/shell nanoparticles.

  16. Comparison of reversible and nonreversible aqueous-soluble lipidized conjugates of salmon calcitonin.

    Science.gov (United States)

    Cheng, Weiqiang; Lim, Lee-Yong

    2008-01-01

    Reversible aqueous lipidization (REAL) at the interdisulfide bond has been shown to improve the deliverability of some peptide drugs. Recently, we developed a nonreversible aqueous lipidization method targeted at the interdisulfide bond of salmon calcitonin (sCT). The resultant derivative had comparable hypocalcemic activity to sCT after subcutaneous injection in rats, despite possessing significantly different biophysical properties. The purpose of this study was to conduct a comparative evaluation of the biophysical properties of the reversible aqueous-soluble lipidized sCT (REAL-sCT) and its corresponding nonreversible aqueous-soluble compound (Mal-sCT) with a view to correlate these properties to the bioactivities of the peptides. REAL-sCT and Mal-sCT were successfully synthesized, purified and identified. Both conjugates showed comparable retention times in a C-18 HPLC column, as well as robust helical structures and aggregation behavior in water, although REAL-sCT was shown by dynamic light scattering experiments to form larger aggregates than Mal-sCT in water. The larger particle size of REAL-sCT correlated with its stronger resistance to degradation by intestinal enzymes. Unlike Mal-sCT, REAL-sCT was rapidly converted to sCT in liver juice; however, the regenerated sCT appeared to degrade at a slower rate than unmodified sCT in the liver juice. Compared with sCT, REAL-sCT after subcutaneous injection as an aqueous solution at a dose of 0.15 mg/kg produced a prolonged hypocalcemic activity that lasted at least 24 h in the rat. Using a novel LC-MS/MS method that was developed for this study, we were able to show concomitant increases in REAL-sCT and sCT plasma concentrations with time, the latter prevailing at 10% the molar concentration of the former. In contrast, sCT was not present in the plasma following the subcutaneous injection of Mal-sCT, although a comparable hypocalcemic activity with shorter duration was observed. Oral administration of REAL

  17. Modeling phase distribution of water-soluble organics in aqueous solutions using surface tension data

    Science.gov (United States)

    Cline, B.; Hiatt, J.; Aumann, E.; Cabrera, J.; Tabazadeh, A.

    2006-12-01

    A good fraction (greater than 30 percent) of submicron particle mass in the atmosphere is often composed of water-soluble organic carbon. Identifiable, water-miscible organics, such as, known sugars, small alcohols, small diacids, etc. comprise only a small fraction of the water-soluble mass (about 1-2 percent). Most of the water-soluble mass is often composed of unidentifiable, humic-like materials, which are commonly refereed to as HULIS. Humic substances are known to form colloids in aqueous solutions at very low aqueous concentrations. Thus, it is likely for HULIS to also be colloid-forming in aqueous solutions. Here, we present surface tension measurements of water-miscible and colloid-forming organics, using methanol and sodium laurate as analogs, respectively. By relating the change in surface tension to chemical potential of the solution, we determine a relationship between surface tension and the surface excess of solute; that is, the number of molecules of solute adsorbed at the surface. Assuming surface acts as a monolayer, we model the adsorption with a Langmuir isotherm to extract the surface excess as a function of solute mole fraction. This relationship allows us to calculate the solute's distribution between bulk and surface phases for methanol, and in bulk, surface and colloid phases for sodium laurate. A colloid of sodium laurate contains approximately 100 laurate anions in a spherical cluster. We present adsorption constants for methanol and sodium laurate (derived from our surface tension data), critical micelle concentration for sodium laurate (derived from our surface tension data), and all the other thermocehmical constants (obtained from the literature) required to constrain a model for determining phase partitioning of organics in aqueous solutions.

  18. Enhancing the aqueous solubility and dissolution of olanzapine using freeze-drying

    Directory of Open Access Journals (Sweden)

    Mudit Dixit

    2011-12-01

    Full Text Available The aim of the present study was to develop an olanzapine freeze-dried tablet (FDT. The solubility and dissolution rate of poorly water-soluble olanzapine was improved by preparing a freeze-dried tablet of olanzapine using the freeze-drying technique . The FDT was prepared by dispersing the drug in an aqueous solution of highly water-soluble carrier materials consisting of gelatin, glycine, and sorbitol. The mixture was poured in to the pockets of blister packs and then was subjected to freezing and lyophilisation. The FDT was characterised by DSC, XRD and SEM and was evaluated for saturation solubility and dissolution. The samples were stored in a stability chamber to investigate their physical stability. Results obtained by DSC and X-ray were analysed and showed the crystalline state of olanzapine in FDT transformation to the amorphous state during the formation of FDT. Scanning electron microscope (SEM results suggest reduction in olanzapine particle size. The solubility of olanzapine from the FDT was observed to be nearly four and a half times greater than the pure drug. Results obtained from dissolution studies showed that olanzapine FDT significantly improved the dissolution rate of the drug compared with the physical mixture (PM and the pure drug. More than 90% of olanzapine in FDT dissolved within 5 minutes, compared to only 19.78% of olanzapine pure drug dissolved over the course of 60 minutes. In a stability test, the release profile of the FDT was unchanged, as compared to the freshly prepared FDT after 90 days of storing.O objetivo do presente estudo foi desenvolver comprimidos liofilizados de olanzapina (FDT. A solubilidade e a taxa de dissolução da olanzapina, fracamente solúvel em água, foram melhoradas com a preparação de comprimidos liofilizados de olanzapina usando a técnica de liofilização. O FDT foi preparado por dispersão do fármaco em solução aquosa de materiais altamente solúveis em água, como gelatina

  19. Solubility of NaCl and KCl in aqueous HCl from 20 to 85°C

    Science.gov (United States)

    Potter, Robert W.; Clynne, Michael A.

    1980-01-01

    The solubilities of NaCl and KCl in aqueous HCl solutions were determined from 20 to 85°C at concentrations ranging from 0 to 20 g of HCl/100 g of solution. Equations are given that describe the solubilities over the range of conditions studied. For NaCl and KCl respectively measured solubilities show an average deviation from these equations of ??0.10 and ??0.08 g/100 g of saturated solution.

  20. Simulations of mean ionic activity coefficients and solubilities in aqueous electrolyte solutions

    Science.gov (United States)

    Panagiotopoulos, Athanassios

    Aqueous electrolyte solutions play an important role in industrial, geochemical and biological applications. The mean ionic activity coefficients quantify the deviation of salt chemical potential from ideal solution behavior; experimental measurements are available for many salts over broad ranges of concentration and temperature, but there have been practically no prior simulation results, because if sampling difficulties for explicit-solvent electrolyte solutions. We have developed a new approach for determination of activity coefficients of aqueous electrolytes. Common fixed-point-charge models for water and ions are unable to reproduce simultaneously activity coefficients and solubilities. Polarizable models perform better, but still predict an incorrect temperature dependence of these properties. Work supported by the U.S. Department of Energy, Office of Basic Energy Science.

  1. Solubility of NaCl in aqueous electrolyte solutions from 10 to 100°C

    Science.gov (United States)

    Clynne, M.A.; Potter, R.W.; Haas, J.L.

    1981-01-01

    The solubilities of NaCl in aqueous KCl, MgCl2, CaCl2, and mixed CaCl2-KCl solutions have been determined from 10 to 100??C. The data were fit to an equation, and the equation was used to calculate values of the change in solubility of NaCl, ???[NaCl]/???T. These values are required for calculations of the rate of migration of fluids in a thermal gradient in rock salt. The data obtained here indicate that the values of ???[NaCl]/???T are 36-73% greater for solutions containing divalent ions than for the NaCl-H2O system.

  2. Conjugation of curcumin onto hyaluronic acid enhances its aqueous solubility and stability.

    Science.gov (United States)

    Manju, S; Sreenivasan, K

    2011-07-01

    Polymer-drug conjugates have gained much attention largely to circumvent lower drug solubility and to enhance drug stability. Curcumin is widely known for its medicinal properties including its anticancer efficacy. One of the serious drawbacks of curcumin is its poor water solubility which leads to reduced bioavailability. With a view to address these issues, we synthesized hyaluronic acid-curcumin (HA-Cur) conjugate. The drug conjugate was characterized using FT-IR, NMR, Dynamic light scattering and TEM techniques. The conjugates, interestingly found to assembles as micelles in aqueous phase. The formation of micelles seems to improve the stability of the drug in physiological pH. We also assessed cytotoxicity of the conjugate using L929 fibroblast cells and quantified by MTT assay. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Solubility and stability of zeolites in aqueous solution: 2. Calcic clinoptilolite and mordenite

    Energy Technology Data Exchange (ETDEWEB)

    Benning, L.G.; Wilkin, R.T.; Barnes, H.L.

    2000-04-01

    The solubilities of Ca-exchanged clinoptilolite (Cpt-Ca) and Ca-exchanged mordenite (Mor-Ca) have been measured in aqueous solutions between 25 and 275 C and at saturated water vapor pressures. Natural zeolites were cation exchanged to close to Ca end-member composition (90% for Cpt-Ca, and 98% for Mor-Ca). The controlling dissolution reactions are reversible as shown by equilibrium constants calculated for approach from under- and supersaturation. The log K{sub sp} for Cpt-Ca increases from {minus}26.9 at 25 C to a maximum of {minus}16.9 at 275 C, whereas for Mor-Ca the equilibrium constant varies from {minus}25.3 at 25 C to {minus}17.7 at 265 C. The solubilities for both zeolites increase with increasing temperature showing a positive enthalpy for the dissolution reaction. At lower temperatures Cpt-Ca is slightly more soluble than Mor-Ca, which agrees with natural observations where mordenite and clinoptilolite commonly occur together spatially but mordenite is in general the higher-temperature phase. A comparison with other exchanged clinoptilolites indicates that Cpt-Ca is more stable than the Na, K, and Mg varieties. The results demonstrate that the exchanged cation has a large effect on the solubility behavior, and that divalently exchanged varieties are less soluble than monovalent varieties. From the solubility constants, the standard Gibbs free energies of formation for hydrous Cpt-Ca and Mor-Ca at 25 C and 1 bar were determined to be {minus}6,387 {+-} 5 kJ/mol and {minus}6,275 {+-} 7 kJ/mol, respectively. However, compared to the hydration states and the aluminosilicate structure, the effect of the cation on the Gibbs free energies of formation is small.

  4. Improving the aqueous solubility of triclosan by solubilization, complexation, and in situ salt formation.

    Science.gov (United States)

    Grove, Christine; Liebenberg, Wilna; du Preez, Jan L; Yang, Wenzhan; de Villiers, Melgardt M

    2003-01-01

    Triclosan, an antimicrobial, although widely incorporated into many skin care products, toothpastes, and liquid soaps, presents formulation difficulties because it is practically insoluble in water. The objective of this study was to improve the aqueous solubility of triclosan through solubilization, complexation, and salt formation. The solubility of triclosan in distilled water and in phosphate buffers (pH 7.4) was determined at 30 degrees C. The order of solubilizing performance of the solubilizers was: N-methylglucamine> or =L-arginine>sodium lauryl sulfate>beta-cyclodextrin> or =hydroxypropyl-beta-cyclodextrin>ethanolamine>sodium benzoate>sodium methyl 4-hydroxybenzoate>triethanolamine> or =diethanolamine. These solubilizers increased the solubility of triclosan from 80- to 6000-fold. Micellar solubilization and the formation of either salts or complexes are postulated as possible mechanisms for the increase in the solubility of triclosan by the surfactant sodium lauryl sulphate, the cyclic sugar derivatives beta-cyclodextrin and 2-hydropropyl-beta-cyclodextrin, the amino acid L-arginine, and the amino sugar alcohol N-methylglucamine. Furthermore, although the bacteriostatic efficacy of triclosan was significantly increased when solubilized with N-methylglucamine, L-arginine, and ethanolamine, increased solubilization did not increase the effectiveness of triclosan for all solubilizers tested.

  5. Zinc(II) oxide solubility and phase behavior in aqueous sodium phosphate solutions at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ziemniak, S.E.; Jones, M.E.; Combs, K.E.S.

    1990-02-01

    A platinum-lined, flowing autoclave facility is used to investigate the solubility/phase behavior of zinc(II) oxide in aqueous sodium phosphate solutions at temperatures between 290 and 560 K. ZnO solubilities are observed to increase continuously with temperature and phosphate concentration. At higher phosphate concentrations, a solid phase transformation to NaZnPO{sub 4} is observed. NaZnPO{sub 4} solubilities are retrograde with temperature. The measured solubility behavior is examined via a Zn(II) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reaction equilibria are obtained from a least-squares analysis of the data. The existence of two new zinc(II) ion complexes is reported for the first time: Zn(OH){sub 2}(HPO{sub 4}){sup 2{minus}} and Zn(OH){sub 3}(H{sub 2}PO{sub 4}){sup 2{minus}}. A summary of thermochemical properties for species in the systems ZnO-H{sub 2}O and ZnO-Na{sub 2}O-P{sub 2}O{sub 5}-H{sub 2}O is also provided. 21 refs., 10 figs., 7 tabs.

  6. Solubility and stability of zeolites in aqueous solution. 1: Analcime, Na-, and K-clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Wilkin, R.T.; Barnes, H.L. [Pennsylvania State Univ., University Park, PA (United States). Ore Deposits Research Section

    1998-07-01

    The solubilities of analcime and clinoptilolite were determined in dilute, weakly alkaline, aqueous solutions below 300 C and at vapor-saturated pressures. Analcimes used in this study were from Mont St. Hilaire, Quebec (an{sub 1}, Si/Al = 2.02) and Wikieup, Arizona (an{sub 2}, Si/Al = 2.55); clinoptilolite samples were from Castle Creek, Idaho (Si/Al = 4.50). The effects of alkali content (Na,K) on clinoptilolite solubility were determined by using cation-exchanged varieties of the Castle Creek material. The logarithm of the equilibrium constants of the solubility-controlling reactions were fit to the function: log K = A + BT + C/T + D log T. At 25 C, log K values for the Mont St. Hilaire analcime, Wikieup analcime, Na-clinoptilolite, and K-clinoptilolite are {minus}16.1, -15.0, -26.5, and {minus}28.1, respectively. These data were combined with the thermodynamic properties of the aqueous species Si(OH){sub 4}, Al(OH){sub 4}{sup {minus}}, Na{sup +}, K{sup +}, and liquid water to determine standard Gibbs free energies of formation as a function of temperature. Values of {Delta}G{sub f}{sup 0} at 25 C and 1 bar for the Mont St. Hilaire analcime and Wikieup analcime are {minus}3,089.2 and {minus}3,044.4 kJ/mol, respectively. The {Delta}G{sub f}{sup 0} values for hydrous Na-clinoptilolite and K-clinoptilolite, respectively, are {minus}6,267.9 and {minus}6,107.4 kJ/mol at 25 C and 1 bar. The solubility data reported here, and results obtained from previous calorimetric studies, indicate that the aluminosilicate frameworks of analcime and clinoptilolite are stabilized by an increase in Al content.

  7. O2 solubility in aqueous media determined by a kinetic method.

    Science.gov (United States)

    Reynafarje, B; Costa, L E; Lehninger, A L

    1985-03-01

    A kinetic method for the determination of O2 solubility in air-saturated aqueous solutions of widely varying composition and temperature is described. It is based on the precise molar stoichiometry between the rates of uptake of H+ and O2, measured with response-matched electrodes, in the reaction NADH + H+ + 1/2O2----NAD+ + H2O, catalyzed by an NADH oxidase preparation. To the initially anaerobic test system, which contains an excess of NADH and NADH oxidase in a buffered medium, an aliquot of the O2-containing solution to be tested is added and the rates of both O2 uptake and H+ uptake are recorded; the H+ electrode is calibrated against standard HCl. From these data the amount of O2 in the aliquot is calculated. Some representative values for O2 solubility at 25 degrees C and 760 mm in air-saturated systems are (i) distilled H2O, 516 nmol O/ml, (ii) 0.15 M KCl, 480 nmol O/ml, and (iii) 0.25 M sucrose, 458 nmol O/ml. Data and equations are also given for the solubility of O2 at 760 mm in air-saturated and lightly buffered 0.15 M KCl and 0.25 M sucrose over the range 5 to 40 degrees C. In the method described the rates of O2 and H+ uptake are precisely linear and stoichiometric when NADH is present in large excess over O2. However, when O2 is in excess and small additions of 340-nm-standardized NADH are made, as in earlier methods based on NADH oxidation, the endpoint is approached very gradually and tends to overestimate O2 solubility, owing to (i) the higher Km for NADH than for O2, (ii) the relatively slow response of the Clark O2 electrode, and (iii) the incomplete oxidation of NADH in the presence of 340-nm-absorbing inhibitory substances.

  8. Aqueous solubilities, vapor pressures, and 1-octanol-water partition coefficients for C9-C14 linear alkylbenzenes

    Science.gov (United States)

    Sherblom, P.M.; Gschwend, P.M.; Eganhouse, R.P.

    1992-01-01

    Measurements and estimates of aqueous solubilities, 1-octanol-water partition coefficients (Kow), and vapor pressures were made for 29 linear alkylbenzenes having alkyl chain lengths of 9-14 carbons. The ranges of values observed were vapor pressures from 0.002 to 0.418 Pa, log Kow, from 6.83 to 9.95, and aqueous solubilities from 4 to 38 nmol??L-1. Measured values exhibited a relationship to both the alkyl chain length and the position of phenyl substitution on the alkyl chain. Measurement of the aqueous concentrations resulting from equilibration of a mixture of alkylbenzenes yielded higher than expected values, indicating cosolute or other interactive effects caused enhanced aqueous concentrations of these compounds. ?? 1992 American Chemical Society.

  9. Aqueous-phase exfoliation of graphite in the presence of polyvinylpyrrolidone for the production of water-soluble graphenes

    Science.gov (United States)

    Bourlinos, Athanasios B.; Georgakilas, Vasilios; Zboril, Radek; Steriotis, Theodore A.; Stubos, Athanasios K.; Trapalis, Christos

    2009-12-01

    Treatment of crystalline graphite fine powder with an aqueous solution of the harmless and versatile substance polyvinylpyrrolidone under sonication results in water-soluble, polymer-protected graphene single layers without oxidation or destruction of the sp 2 character of the carbon core. The liquid-phase extraction of graphene monolayers was evidenced by TEM and AFM techniques, while their graphitic character was checked with Raman spectroscopy. Besides PVP, the water-soluble biopolymers albumin and sodic carboxymethylcellulose were also employed successfully in the aqueous-phase exfoliation of graphite, thereby supporting the generic character of the present method using a variety of suitable polymeric extractants.

  10. Impact of Polymer Conformation on the Crystal Growth Inhibition of a Poorly Water-Soluble Drug in Aqueous Solution

    OpenAIRE

    Schram, Caitlin J.; Beaudoin, Stephen P.; Taylor, Lynne S.

    2014-01-01

    Poor aqueous solubility is a major hindrance to oral delivery of many emerging drugs. Supersaturated drug solutions can improve passive absorption across the gastrointestinal tract membrane as long as crystallization can be inhibited, enhancing the delivery of such poorly soluble therapeutics. Polymers can inhibit crystallization and prolong supersaturation; therefore, it is desirable to understand the attributes which render a polymer effective. In this study, the conformation of a polymer a...

  11. Correlation of the solubility of several aromatics and terpenes in aqueous hydroxypropyl-beta-cyclodextrin with steric and hydrophobicity parameters.

    Science.gov (United States)

    Demian, B A

    2000-10-06

    The solubility isotherms of nineteen aromatics and terpenes in aqueous hydroxypropyl-beta-cyclodextrin were determined to be straight lines. This is explained by the host-guest complexation which is characteristic for the whole class of cyclodextrins and derivatives. The slopes of the solubility isotherms correlate with Sterimol L and log P(ow) as descriptors of the steric fit and hydrophobicity match, in accord with the qualitative representation of the phenomenon.

  12. A study of vehicles for dosing rodent whole embryo culture with non aqueous soluble compounds.

    Science.gov (United States)

    Augustine-Rauch, Karen A; Zhang, Qin; Kleinman, Mark; Lawton, Richard; Welsh, Michael J

    2004-05-01

    In rodent whole embryo culture (WEC), finding vehicles for non-aqueous-soluble compounds has been problematic due to developmental toxicity associated with many solvents. The purpose of this study was to identify alternative vehicles for insoluble compounds. In WEC, we evaluated carrier solutions containing bovine serum albumin (BSA) and glycerol as well as the solvents, formamide, dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and ethanol, for relative teratogenicity and delivery of the insoluble teratogen, all-trans retinoic acid (RA). At a concentration of glycerol carrier solutions were not teratogenic, although both inhibited robust formation of yolk sac vasculature. Both solutions delivered RA to the cultured rat embryos at higher doses. In summary, all four solvents/solutions may have utility as vehicles dependent upon the chemical properties of the compound to be solubilized.

  13. Solubility and reactivity of peroxyacetyl nitrate (PAN) in dilute aqueous salt solutions and in sulphuric acid

    Science.gov (United States)

    Frenzel, A.; Kutsuna, S.; Takeuchi, K.; Ibusuki, T.

    The loss rates of PAN in several dilute aqueous salt solutions (NaBr, Na 2SO 3, KI, NaNO 2, FeCl 3, and FeSO 4) and in sulphuric acid were measured at 279 K with a simple bubbler experiment. They are little different from that in pure water. For 5 M sulphuric acid hydrolysis and solubility were determined in the temperature range of 243-293 K. The hydrolysis rate kh=3.2×10 -4 s -1 at 293 K is close to that in water. The observed temperature dependence of the Henry's Law constant H=10- 6.6±0.6exp((4780±420)/T) M atm -1 leads to enthalpy and entropy of solvation Δ Hsolv=-39.7±3.5 kJ mol -1 and Δ Ssolv=-126±11 J mol -1 K -1, respectively.

  14. Effect of soluble polysaccharides addition on rheological properties and microstructure of chitin nanocrystal aqueous dispersions.

    Science.gov (United States)

    Tzoumaki, Maria V; Moschakis, Thomas; Biliaderis, Costas G

    2013-06-05

    Mixtures of chitin nanocrystal aqueous dispersions (at pH 3.0) with soluble polysaccharides of varying molecular features were examined rheologically and microscopically, under different conditions of biopolymer concentration, ionic strength, pH and temperature. The addition of non-adsorbing polysaccharides (guar gum, locust bean gum and xanthan) as well as oppositely charged (κ-carrageenan) to a chitin nanocrystal dispersion, resulted in a network formation and the gel strength increased with the chitin nanocrystal concentration. In contrast, the chitin nanocrystal - chitosan or - pullulan mixed dispersions did not show any network formation (tanδ>1) at the concentration range examined. An increase in ionic strength and pH also resulted in an enhanced elasticity of the chitin nanocrystal-guar gum dispersions. Furthermore, an increase in the elastic modulus, which was irreversible upon cooling, was observed upon heating the chitin nanocrystal-polysaccharide mixed dispersions.

  15. An explanation of dispersion states of single-walled carbon nanotubes in solvents and aqueous surfactant solutions using solubility parameters.

    Science.gov (United States)

    Ham, Hyeong Taek; Choi, Yeong Suk; Chung, In Jae

    2005-06-01

    Dispersions of single-walled carbon nanotubes in various solvents and aqueous surfactant emulsions were investigated to correlate the degree of dispersion state with Hansen solubility parameters (deltat2=deltad2+deltap2+deltah2). It was found that the nanotubes were dispersed or suspended very well in the solvents with certain dispersive component (deltad) values. They were precipitated in the solvents with high polar component (deltap) values or hydrogen-bonding component (deltah) values. The solvents in the dispersed group occupied a certain region in a 3-dimensional space of three components. The surfactants with a lipophilic group equal to and longer than decyl, containing 9 methylene groups and 1 methyl group, contributed to the dispersion of nanotubes in water. The surfactants in the dispersed group had a lower limit in the dispersive component (deltad) of the Hansen parameter.

  16. Estimating the physicochemical properties of polyhalogenated aromatic and aliphatic compounds using UPPER: part 2. Aqueous solubility, octanol solubility and octanol-water partition coefficient.

    Science.gov (United States)

    Admire, Brittany; Lian, Bo; Yalkowsky, Samuel H

    2015-01-01

    The UPPER (Unified Physicochemical Property Estimation Relationships) model uses additive and non-additive parameters to estimate 20 biologically relevant properties of organic compounds. The model has been validated by Lian and Yalkowsky (2014) on a data set of 700 hydrocarbons. Recently, Admire et al. (2014) expanded the model to predict the boiling and melting points of 1288 polyhalogenated benzenes, biphenyls, dibenzo-p-dioxins, diphenyl ethers, anisoles and alkanes. In this work, 19 new group descriptors are determined and used to predict the aqueous solubilities, octanol solubilities and the octanol-water coefficients.

  17. Water sorption and solubility of dental composites and identification of monomers released in an aqueous environment.

    Science.gov (United States)

    Ortengren, U; Wellendorf, H; Karlsson, S; Ruyter, I E

    2001-12-01

    Water sorption and solubility of six proprietary composite resin materials were assessed, and monomers eluted from the organic matrix during water storage identified. Water sorption and solubility tests were carried out with the following storage times: 4 h, 24 h and 7, 60 and 180 days. After storage, water sorption and solubility were determined. Eluted monomers were analysed by high performance liquid chromatography (HPLC). Correlation between the retention time of the registered peak and the reference peak was observed, and UV-spectra confirmed the identity. The results showed an increase in water sorption until equilibrium for all materials with one exception. The solubility behaviour of the composite resin materials tested revealed variations, with both mass decrease and increase. The resin composition influences the water sorption and solubility behaviour of composite resin materials. The HPLC analysis of eluted components revealed that triethyleneglycol dimethacrylate (TEGDMA) was the main monomer released. Maximal monomer concentration in the eluate was observed after 7 days. During the test period, quantifiable quantities of urethanedimethacrylate (UEDMA) monomer were observed, whereas 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane (Bis-GMA) was only found in detectable quantities. No detectable quantities of bisphenol-A were observed during the test period.

  18. Solubility of vanadium from manganese vanadates in aqueous solutions of soda ash

    Science.gov (United States)

    Khalezov, B. D.; Krasheninin, A. G.; Vatolin, N. A.; Ovchinnikova, L. A.

    2016-05-01

    It is shown that, in the course of developing the technology of pure vanadium pentoxide preparation from manganic vanadium-containing metallurgical slags, their oxidative roasting and cinder formation without alkaline additives are accompanied by the decomposition of spinelides with the formation of manganese meta- and pyrovanadates. Concentrated aqueous solutions of soda ash with an Na2CO3 concentration of 120-150 g/dm3 are accepted as a selective leaching reagent for vanadium from a cinder. Manganese metaand pyrovanadates are synthesized, and the procedure of their preparation is presented. The solubility of vanadium from manganese vanadates in aqueous solutions of soda ash at C_{Na_2 CO_3 } = 150 g/dm^3 is studied at 20-95°C for pyrovanadate and at 85-95°C for metavanadate. It is shown that vanadium should be leached from converter manganic slags roasted without alkaline metal additives at a leaching solution temperature higher than 95°C. There is a possibility to increase the vanadium content in a leaching solution to 60-80 g/dm3. The results obtained are used in the development of the technology of vanadium leaching.

  19. Unexpectedly Enhanced Solubility of Aromatic Amino Acids and Peptides in an Aqueous Solution of Divalent Transition-Metal Cations

    Science.gov (United States)

    Shi, Guosheng; Dang, Yaru; Pan, Tingting; Liu, Xing; Liu, Hui; Li, Shaoxian; Zhang, Lijuan; Zhao, Hongwei; Li, Shaoping; Han, Jiaguang; Tai, Renzhong; Zhu, Yiming; Li, Jichen; Ji, Qing; Mole, R. A.; Yu, Dehong; Fang, Haiping

    2016-12-01

    We experimentally observed considerable solubility of tryptophan (Trp) in a CuCl2 aqueous solution, which could reach 2-5 times the solubility of Trp in pure water. Theoretical studies show that the strong cation-π interaction between Cu2 + and the aromatic ring in Trp modifies the electronic distribution of the aromatic ring to enhance significantly the water affinity of Trp. Similar solubility enhancement has also been observed for other divalent transition-metal cations (e.g., Zn2 + and Ni2 + ), another aromatic amino acid (phenylalanine), and three aromatic peptides (Trp-Phe, Phe-Phe, and Trp-Ala-Phe).

  20. Prediction of aqueous solubility, vapor pressure and critical micelle concentration for aquatic partitioning of perfluorinated chemicals.

    Science.gov (United States)

    Bhhatarai, Barun; Gramatica, Paola

    2011-10-01

    The majority of perfluorinated chemicals (PFCs) are of increasing risk to biota and environment due to their physicochemical stability, wide transport in the environment and difficulty in biodegradation. It is necessary to identify and prioritize these harmful PFCs and to characterize their physicochemical properties that govern the solubility, distribution and fate of these chemicals in an aquatic ecosystem. Therefore, available experimental data (10-35 compounds) of three important properties: aqueous solubility (AqS), vapor pressure (VP) and critical micelle concentration (CMC) on per- and polyfluorinated compounds were collected for quantitative structure-property relationship (QSPR) modeling. Simple and robust models based on theoretical molecular descriptors were developed and externally validated for predictivity. Model predictions on selected PFCs were compared with available experimental data and other published in silico predictions. The structural applicability domains (AD) of the models were verified on a bigger data set of 221 compounds. The predicted properties of the chemicals that are within the AD, are reliable, and they help to reduce the wide data gap that exists. Moreover, the predictions of AqS, VP, and CMC of most common PFCs were evaluated to understand the aquatic partitioning and to derive a relation with the available experimental data of bioconcentration factor (BCF).

  1. Molecular simulation study on Hofmeister cations and the aqueous solubility of benzene.

    Science.gov (United States)

    Ganguly, Pritam; Hajari, Timir; van der Vegt, Nico F A

    2014-05-22

    We study the ion-specific salting-out process of benzene in aqueous alkali chloride solutions using Kirkwood-Buff (KB) theory of solutions and molecular dynamics simulations with different empirical force field models for the ions and benzene. Despite inaccuracies in the force fields, the simulations indicate that the decrease of the Setchenow salting-out coefficient for the series NaCl > KCl > RbCl > CsCl is determined by direct benzene-cation correlations, with the larger cations showing weak interactions with benzene. Although ion-specific aqueous solubilities of benzene may be affected by indirect ion-ion, ion-water, and water-water correlations, too, these correlations are found to be unimportant, with little to no effect on the Setchenow salting-out coefficients of the various salts. We further considered LiCl, which is experimentally known to be a weaker salting-out agent than NaCl and KCl and, therefore, ranks at an unusual position within the Hofmeister cation series. The simulations indicate that hydrated Li(+) ions can take part of the benzene hydration shell while the other cations are repelled by it. This causes weaker Li(+) exclusion around the solute and a resulting, weaker salting-out propensity of LiCl compared to that of the other salts. Removing benzene-water and benzene-salt electrostatic interactions in the simulations does not affect this mechanism, which may therefore also explain the smaller effect of LiCl, as compared to that of NaCl or KCl, on aqueous solvation and hydrophobic interaction of nonpolar molecules.

  2. Relation between the solubility of proteins in aqueous solutions and the second virial coefficient of the solution

    NARCIS (Netherlands)

    Haas, C; Drenth, J; Wilson, WW

    1999-01-01

    Tn recent publications it was pointed out that there is a correlation between the observed values of the solubility of proteins in aqueous solutions and the second virial coefficient of the solution. In this paper we give a theoretical explanation of this relation. The derived theoretical expression

  3. Relation between the solubility of proteins in aqueous solutions and the second virial coefficient of the solution

    NARCIS (Netherlands)

    Haas, C; Drenth, J; Wilson, WW

    1999-01-01

    Tn recent publications it was pointed out that there is a correlation between the observed values of the solubility of proteins in aqueous solutions and the second virial coefficient of the solution. In this paper we give a theoretical explanation of this relation. The derived theoretical expression

  4. Estimation of octanol/water partition coefficient and aqueous solubility of environmental chemicals using molecular fingerprints and machine learning methods

    Science.gov (United States)

    Octanol/water partition coefficient (logP) and aqueous solubility (logS) are two important parameters in pharmacology and toxicology studies, and experimental measurements are usually time-consuming and expensive. In the present research, novel methods are presented for the estim...

  5. Estimation of octanol/water partition coefficient and aqueous solubility of environmental chemicals using molecular fingerprints and machine learning methods

    Science.gov (United States)

    Octanol/water partition coefficient (logP) and aqueous solubility (logS) are two important parameters in pharmacology and toxicology studies, and experimental measurements are usually time-consuming and expensive. In the present research, novel methods are presented for the estim...

  6. Aqueous Solubility and Degradation Kinetics of the Phytochemical Anticancer Thymoquinone; Probing the Effects of Solvents, pH and Light

    Directory of Open Access Journals (Sweden)

    Jumah Masoud M. Salmani

    2014-05-01

    Full Text Available Thymoquinone (TQ is a potent anticancer phytochemical with confirmed in vitro efficacy. Its clinical use has not yet established, and very few reports have documented its formulation. There also are no reports about the aqueous solubility and stability of this valuable drug, despite their direct correlation with the in vivo efficacy. In the current research, we have established and validated a stability-indicating HPLC method for the detection of TQ and its degradation products under different conditions. We then investigated the solubility and stability profiles of TQ in aqueous solutions. The stability study was aimed to determine the effect of pH, solvent type and light on the degradation process of TQ, along with the investigation of the kinetics of this degradation. The solubility of TQ varied in different aqueous solvents, and might be compromised due to stability issues. However, these findings confirm that the aqueous solubility is not the major obstacle for the drug formulations mainly due to the considerable water solubility (>500 μg/mL that may be enough to exert pharmacologic effects if administered via parenteral route. Stability study results showed a very low stability profile of TQ in all the aqueous solutions with rapid degradation that varied with solvent type. The study of the degradation kinetics showed a significant effect of pH on the degradation process. The process followed first order kinetics at more acidic and alkaline pH values, and second order kinetics at pH 5–7.4, regardless of the solvent type. The results also expressed that light has a greater impact on the stability of TQ as a shorter period of exposure led to severe degradation, independent of the solution pH and solvent type. Our results also addressed some discrepancies in previously published researches regarding the formulation and quantification of TQ with suggested solutions. Overall, the current study concludes that TQ is unstable in aqueous

  7. Aqueous solubility data for pressurized hot water extraction for solid heterocyclic analogs of anthracene, phenanthrene and fluorene.

    Science.gov (United States)

    Karásek, Pavel; Planeta, Josef; Roth, Michal

    2007-01-26

    We report the aqueous solubilities of phenanthrene and several solid three-ring aromatic heterocycles (phenanthridine, acridine, phenazine, thianthrene, phenothiazine, phenoxathiin, phenoxazine, carbazole, dibenzofuran, dibenzothiophene, and 4,6-dimethyldibenzothiophene) at temperatures ranging from 313K to the solute melting point and at a pressure of 5MPa. The data were measured by dynamic saturation method using an in-house-assembled apparatus for pressurized hot water extraction (PHWE). The solute from a known mass of the saturated aqueous solution was transferred to an organic solvent (hexane or toluene), and the organic phase was analyzed by GC/MS. In any of the solutes, the GC/MS records did not indicate any noticeable decomposition within the temperature range of the measurements. The resultant solubilities were converted to activity coefficients of the individual solutes in saturated aqueous solutions, and the results are discussed in terms of temperature and type/number of heteroatoms.

  8. 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.

  9. Lyotropic, liquid crystalline nanostructures of aqueous dilutions of SMEDDS revealed by small-angle X-ray scattering: impact on solubility and drug release.

    Science.gov (United States)

    Goddeeris, Caroline; Goderis, Bart; Van den Mooter, Guy

    2010-05-12

    The present study was conducted to characterise the liquid crystalline phases that occur upon diluting a SMEDDS and to elucidate the role of these phases on drug solubilisation and release. Small-angle X-ray scattering (SAXS) was used to probe the structures in aqueous dilutions of 3 SMEDDS consisting of propylene glycol mono- and dicaprylate and mono- and dicaprate (PGDCDC) and d-alpha-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000), polysorbate 80 (P80) or polyoxyl 40 hydrogenated castor oil (P40HC). The scattering patterns revealed the formation of either a random periodic or a lamellar phase when 10% (w/w) water was added. All formulations exhibited lamellar structures at 20% (w/w) aqueous dilution, of which the layer-to-layer distance increased upon further addition of water. At 40% (w/w) water, a hexagonal or lamellar phase was formed, depending on the geometry of the surfactant. Temperature did not alter the phases formed. Incorporation of the drug UC 781 only slightly enlarged the characteristic dimensions of the liquid crystalline phases. Drug solubility decreased upon aqueous dilution, although 10% (w/w) dilutions of PGDCDC-P80 SMEDDS and PGDCDC-TPGS 1000 SMEDDS revealed a highly increased solubility as compared to the pure formulations. Drug release data revealed that UC 781 release could not be linked to the solubilisation capacity of the SMEDDS, but could be associated with the solubility of UC 781 in the phases formed at water concentrations above 10% (w/w).

  10. Aqueous solubility of calcium citrate and interconversion between the tetrahydrate and the hexahydrate as a balance between endothermic dissolution and exothermic complex formation

    DEFF Research Database (Denmark)

    Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Aqueous solubility of calcium citrate tetrahydrate was found to decrease with increasing temperature, while solubility of hexahydrate increased with a transition temperature at 51.6 °C. Excess citrate increased calcium citrate solubility but decreased the calcium ion activity of the saturated sol...

  11. Solubility and Bioavailability Enhancement of Poorly Aqueous Soluble Atorvastatin: In Vitro, Ex Vivo, and In Vivo Studies

    Directory of Open Access Journals (Sweden)

    Madhuri S. Rodde

    2014-01-01

    Full Text Available The objective of this investigation was to improve the solubility of the poorly water soluble drug atorvastatin (ATR, using solid dispersion (SD techniques, with Neem Gum (NG as a hydrophilic carrier. The effects of the polymer concentration and method of preparation on the solubility and dissolution rate were studied. The results showed that the solubility of ATR increases with increasing NG concentration. However, dissolution rate of ATR from its SD was dependent on the method used to prepare SD. An in vitro drug release study revealed that the solvent evaporation technique is a more convenient and effective method of preparing SD than kneading method. The SD was characterized using DSC, SEM, and XRD study. An in vivo study was performed in which the 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG CoA reductase inhibition activity was measured. A significant reduction in HMG CoA reductase activity was observed with SD of ATR compared with the plain drug. An ex vivo absorption study was carried out using modified apparatus developed in our laboratory. The in vitro drug release and in vivo and ex vivo studies clearly demonstrated the potential of hydrophilic NG in enhancing the solubility, dissolution rate, and bioavailability of ATR.

  12. Thermodynamic model for the solubility of BaSeO{sub 4}(cr) in the aqueous Ba{sup 2+}-SeO{sub 4}{sup 2-}-Na{sup +}-H{sup +}-OH{sup -}-H{sub 2}O system. Extending to high selenate concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Dhanpat [Rai Enviro-Chem, LLC, Yachats, OR (United States); Felmy, Andrew R. [Pacific Northwest National Laboratory, Richland, WA (United States); Kitamura, Akira; Yoshikawa, Hideki; Doi, Reisuke; Yoshida, Yasushi [Japan Atomic Energy Agency, Tokai-mura (Japan); Moore, Dean A.

    2014-11-01

    The aqueous solubility of BaSeO{sub 4}(cr) was studied at 23 ± 2 C as a function of Na{sub 2}SeO{sub 4} concentrations (0.0001 to 4.1 mol kg{sup -1}) and equilibration periods (3 to 596 d). The equilibrium, approached from both the under- and over-saturation directions, in this system was reached rather rapidly (≤ 3d). The SIT and Pitzer's ion-interaction models were used to interpret these data and the predictions based on both of these models agreed closely with the experimental data. Thermodynamic analyses of the data show that BaSeO{sub 4}(cr) is the solubility-controlling phase for Na{sub 2}SeO{sub 4} concentrations < 0.59 mol kg{sup -1}. The log{sub 10}K{sup 0} value for the BaSeO{sub 4}(cr) solubility product (BaSeO{sub 4}(cr) ↔ Ba{sup 2+} + SeO{sub 4}{sup 2-}) calculated by the SIT and Pitzer models were very similar (-7.32 ± 0.07 with Pitzer and -7.25 ± 0.11 with SIT). Although the BaSeO{sub 4}(cr) solubility product and Ba concentrations as a function of Na{sub 2}SeO{sub 4} concentrations predicted by both the SIT and Pitzer models are similar, the models required different sets of fitting parameters. For examples, (1) interpretations using the SIT model required the inclusion of Ba(SeO{sub 4}){sub 2}{sup 2-} species with log{sub 10}K{sup 0} = 3.44 ± 0.12 for the reaction (Ba{sup 2+} + 2SeO{sub 4}{sup 2-} ↔ Ba(SeO{sub 4}){sub 2}{sup 2-}), whereas these species are not needed for Pitzer model, and (2) at Na{sub 2}SeO{sub 4} concentrations > 0.59 mol kg{sup -1} it was also possible to calculate the value for log{sub 10}K{sup 0} for the solubility product of a proposed double salt (Na{sub 2}Ba(SeO{sub 4}){sub 2}(s) ↔ 2Na{sup +} + Ba{sup 2+} + 2SeO{sub 4}{sup 2-}) which for the SIT model is -(8.70 ± 0.29) whereas for the Pitzer model it is -(9.19 ± 0.19). The ion-interaction/ion-association parameters hitherto unavailable for both the SIT and Pitzer models required to fit these extensive data extending to as high ionic strengths as 12.3 mol

  13. Small-Molecule Inhibitors of Cytokine-Mediated STAT1 Signal Transduction In ß-Cells With Improved Aqueous Solubility

    DEFF Research Database (Denmark)

    Scully, Stephen Shane; Tang, Alicia J; Lundh, Morten;

    2013-01-01

    We previously reported the discovery of BRD0476 (1), a small molecule generated by diversity-oriented synthesis that suppresses cytokine-induced ß-cell apoptosis. Herein, we report the synthesis and biological evaluation of 1 and analogs with improved aqueous solubility. By replacing naphthyl wit...... with quinoline moieties, we prepared active analogs with up to a 1400-fold increase in solubility from 1. In addition, we demonstrated that compound 1 and analogs inhibit STAT1 signal transduction induced by IFN-¿....

  14. Effects of aqueous-soluble organic compounds on the removal of selected radionuclides from high-level waste part I: Distribution of Sr, Cs, and Tc onto 18 absorbers from an irradiated, organic-containing leachate simulant for Hanford Tank 101-SY

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F. [Sandia National Labs., Albuquerque, NM (United States); Svitra, Z.V.; Bowen, S.M. [Los Alamos National Lab., NM (United States)

    1995-01-01

    Many of the radioactive waste storage tanks at U.S. Department of Energy facilities contain organic compounds that have been degraded by radiolysis and chemical reactions. In this investigation, we measured the effect of some aqueous-soluble organic compounds on the sorption of strontium, cesium, and technetium onto 18 absorbers that offer high sorption of strontium from organic-free solutions. For our test solution we used a leachate from a simulated slurry for Hanford Tank 101-SY that initially contained ethylenediaminetetraacetic acid (EDTA) and then was gamma-irradiated to 34 Mrads. We measured distribution coefficients (Kds) for each element/absorber combination for dynamic contact periods of 30 min, 2 h, and 6 h to obtain information about sorption kinetics. To facilitate comparisons, we include Kd values for these same element/absorber combinations from three organic-free simulant solutions. The Kd values for strontium sorption from the simulant that contained the degraded organics usually decreased by large factors, whereas the Kd values for cesium and technetium sorption were relatively unaffected.

  15. EQ3NR, a computer program for geochemical aqueous speciation-solubility calculations: Theoretical manual, user`s guide, and related documentation (Version 7.0); Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Wolery, T.J.

    1992-09-14

    EQ3NR is an aqueous solution speciation-solubility modeling code. It is part of the EQ3/6 software package for geochemical modeling. It computes the thermodynamic state of an aqueous solution by determining the distribution of chemical species, including simple ions, ion pairs, and complexes, using standard state thermodynamic data and various equations which describe the thermodynamic activity coefficients of these species. The input to the code describes the aqueous solution in terms of analytical data, including total (analytical) concentrations of dissolved components and such other parameters as the pH, pHCl, Eh, pe, and oxygen fugacity. The input may also include a desired electrical balancing adjustment and various constraints which impose equilibrium with special pure minerals, solid solution end-member components (of specified mole fractions), and gases (of specified fugacities). The code evaluates the degree of disequilibrium in terms of the saturation index (SI = 1og Q/K) and the thermodynamic affinity (A = {minus}2.303 RT log Q/K) for various reactions, such as mineral dissolution or oxidation-reduction in the aqueous solution itself. Individual values of Eh, pe, oxygen fugacity, and Ah (redox affinity) are computed for aqueous redox couples. Equilibrium fugacities are computed for gas species. The code is highly flexible in dealing with various parameters as either model inputs or outputs. The user can specify modification or substitution of equilibrium constants at run time by using options on the input file.

  16. Improving aqueous solubility and antitumor effects by nanosized gambogic acid-mPEG2000 micelles

    Directory of Open Access Journals (Sweden)

    Cai LL

    2013-12-01

    Full Text Available Lulu Cai,1,* Neng Qiu,2,* Mingli Xiang,3,* Rongsheng Tong,1 Junfeng Yan,1 Lin He,1 Jianyou Shi,1 Tao Chen,4 Jiaolin Wen,3 Wenwen Wang,3 Lijuan Chen31Department of Pharmacy, Sichuan Academy of Medical Science and Sichuan Provincial People's Hospital, 2College of Materials and Chemistry and Chemical Engineering, Chengdu University of Technology, 3State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, People's Republic of China; 4Faculty of Pharmacy, University of Montreal, Montreal, QC, Canada *These authors contributed equally to this paperAbstract: The clinical application of gambogic acid, a natural component with promising antitumor activity, is limited due to its extremely poor aqueous solubility, short half-life in blood, and severe systemic toxicity. To solve these problems, an amphiphilic polymer-drug conjugate was prepared by attachment of low molecular weight (ie, 2 kDa methoxy poly(ethylene glycol methyl ether (mPEG to gambogic acid (GA-mPEG2000 through an ester linkage and characterized by 1H nuclear magnetic resonance. The GA-mPEG2000 conjugates self-assembled to form nanosized micelles, with mean diameters of less than 50 nm, and a very narrow particle size distribution. The properties of the GA-mPEG2000 micelles, including morphology, stability, molecular modeling, and drug release profile, were evaluated. MTT (3-(4,5-dimethylthiazol-2-yl-2,5 diphenyl tetrazolium bromide tests demonstrated that the GA-mPEG2000 micelle formulation had obvious cytotoxicity to tumor cells and human umbilical vein endothelial cells. Further, GA-mPEG2000 micelles were effective in inhibiting tumor growth and prolonged survival in subcutaneous B16-F10 and C26 tumor models. Our findings suggest that GA-mPEG2000 micelles may have promising applications in tumor therapy.Keywords: gambogic acid, poly(ethylene glycol-drug conjugate, micelle, antitumor, toxicity

  17. Application of TLSER method in predicting the aqueous solubility and n-octanol/water partition coefficient of PCBs, PCDDs and PCDFs

    Institute of Scientific and Technical Information of China (English)

    HUANG Jun; YU Gang; ZHANG Zu-lin; WANG Yi-lei; ZHU Wei-hua; WU Guo-shi

    2004-01-01

    The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and noctanol/water partition coefficient of three groups of environmentally important chemicals-polychlorinated biphenyls( PCBs), polychlorinated dibenzodioxins and dibenzofurans( PCDDs and PCDFs). For each compound, five quantum parameters were calculated using AMI semiempirical molecular orbital methods and used as structure descriptors: average molecular polarizability(α), energy of the lowest unoccupied molecular orbit( ELUMO ), energy of the highest occupied molecular orbit( EHOMO ), the most positive charge on a hydrogen atom ( q + ), and the most negative atomic partial charge( q_ ) in the solute molecule. Then standard independent variables in TLSER equation was extracted and two series of quantitative equations between these quantum parameters and aqueous solubility and n-octanol/water partition coefficient were obtained by stepwise multiple linear regression(MLR) method. The developed equations have both quite high accuracy and explicit meanings. And the cross-validation test illustrated the good predictive power and stability of the established models.The results showed that TLSER could be used as a promising approach in the estimation of partition and solubility properties ofmacromolecular chemicals, such as persistent organic pollutants.

  18. Molecular simulation of aqueous electrolyte solubility. 2. Osmotic ensemble Monte Carlo methodology for free energy and solubility calculations and application to NaCl.

    Science.gov (United States)

    Moučka, Filip; Lísal, Martin; Škvor, Jiří; Jirsák, Jan; Nezbeda, Ivo; Smith, William R

    2011-06-23

    We present a new and computationally efficient methodology using osmotic ensemble Monte Carlo (OEMC) simulation to calculate chemical potential-concentration curves and the solubility of aqueous electrolytes. The method avoids calculations for the solid phase, incorporating readily available data from thermochemical tables that are based on well-defined reference states. It performs simulations of the aqueous solution at a fixed number of water molecules, pressure, temperature, and specified overall electrolyte chemical potential. Insertion/deletion of ions to/from the system is implemented using fractional ions, which are coupled to the system via a coupling parameter λ that varies between 0 (no interaction between the fractional ions and the other particles in the system) and 1 (full interaction between the fractional ions and the other particles of the system). Transitions between λ-states are accepted with a probability following from the osmotic ensemble partition function. Biasing weights associated with the λ-states are used in order to efficiently realize transitions between them; these are determined by means of the Wang-Landau method. We also propose a novel scaling procedure for λ, which can be used for both nonpolarizable and polarizable models of aqueous electrolyte systems. The approach is readily extended to involve other solvents, multiple electrolytes, and species complexation reactions. The method is illustrated for NaCl, using SPC/E water and several force field models for NaCl from the literature, and the results are compared with experiment at ambient conditions. Good agreement is obtained for the chemical potential-concentration curve and the solubility prediction is reasonable. Future improvements to the predictions will require improved force field models.

  19. Temperature-dependent spectroscopic evidences of curcumin in aqueous medium: a mechanistic study of its solubility and stability.

    Science.gov (United States)

    Jagannathan, Ramya; Abraham, Priya Mary; Poddar, Pankaj

    2012-12-20

    In curcumin, keto-enol-enolate equilibrium of the heptadiene-dione moiety determines its physiochemical and antioxidant properties. However, its poor solubility in water at neutral pH and room temperature decreases its bioavailability. Potential therapeutic applications have triggered an interest in manipulating the solubility of curcumin in water as its stability and solubility in water remains poorly understood. Here, the mechanism behind its solubility at various temperatures and the influence of interplay of temperature, intramolecular H-bonding, and intermolecular forces is reported, which leads to aggregation-disaggregation at various temperatures. Remarkable change is observed in temperature-dependent electronic transition behavior of curcumin, however, the absorption spectra after cooling and heating cycles remain unchanged, hinting much better thermal stability of curcumin in water than previously thought. This study indicates that it is perhaps the breaking of intramolecular hydrogen bonding which leads to exposure of polar groups and hence responsible for the dissolution of curcumin at higher temperature. The formation of intermolecular aggregates might be responsible behind a better room temperature stability of the molecules after cooling its aqueous suspension from 90 to 25 °C. These curcumin solubility studies have great application in biological research with reference to bioavailability and to understand target oriented mode of action of curcumin.

  20. Removal of chromium from aqueous solution by complexation-ultrafiltration using a water-soluble macroligand.

    Science.gov (United States)

    Aliane, A; Bounatiro, N; Cherif, A T; Akretche, D E

    2001-06-01

    A process for purifying waste waters containing heavy and toxic metal such as chromium has been studied. A batch complexation-ultrafiltration process was used to concentrate and recover chromium from sulphate solution. As the chromium ions are too small to be retained by the filter, they are first complexed with a water-soluble macroligand (polyethylene-imine). Factors affecting the rejection rate and permeate flux such as pH, concentration ligand, chloride and sulphate concentration, membrane pore size, applied pressure and extraction factor were investigated. Best operating conditions can be obtained in order to achieve high levels of removal (> 95%). Then, decomplexation is obtained so that metal can be separated from macroligand by a second ultrafiltration plant to reuse the macroligand.

  1. Dependence of the solubility of atmospheric oxygen in weakly alkaline aqueous solutions on surfactant concentration

    Science.gov (United States)

    Chistyakova, G. V.; Koksharov, S. A.; Vladimirova, T. V.

    2012-11-01

    The solubility of atmospheric oxygen in solutions of surfactants of different natures at 293 K and pH 8 is determined by gas chromatography. It is found that additives of nonionic surfactants decrease the oxygen content in the solution in the premicellar region and increase its solubility in the micellar region. It is shown that, for anionic surfactants, a decrease in the solubility of O2 is observed over the entire concentration range.

  2. Development of a Design Tool for Planning Aqueous Amendment Injection Systems Soluble Substrate Design Tool

    Science.gov (United States)

    2012-06-01

    injection with water to distribute the soluble substrate throughout the treatment zone. Once injected, the soluble substrate is fermented molecular...hydrogen (H2) and acetate by common subsurface microorganisms. This H2 and acetate are then used as electron donors for anaerobic biodegradation of the... fermentable organic substrate is diluted with water and distributed throughout the target treatment zone. The soluble substrate is fermented to molecular

  3. Facile synthesis of a water-soluble fluorescence sensor for Al3 + in aqueous solution and on paper substrate

    Science.gov (United States)

    Liu, Tianqi; Wan, Xuejuan; Dong, Yunsheng; Li, Weibin; Wu, Lisi; Pei, Hang; Yao, Youwei

    2017-02-01

    In this study, a facile water-soluble fluorescence sensor 2-((2-hydroxybenzylidene)-amino)-2-(hydroxymethyl)propane-1,3-diol (ST) was synthesized via one-step reaction, and its fluorescence sensing performance for Al3 + both in aqueous solution and on paper substrate was evaluated. The results showed that ST exhibited an specific fluorescence "turn-on" response to Al3 + over other cations in aqueous solution as well as on the test paper. The limit of detection was found to be 3.2 × 10- 7 M, which revealed that the obtained Schiff-base based fluorescence chemosensor ST possessed a great potential for the rapid, quantitative and qualitative detection of Al3 +.

  4. A water-soluble sulfonate-BODIPY based fluorescent probe for selective detection of HOCl/OCl⁻ in aqueous media.

    Science.gov (United States)

    Kim, Jiyoung; Kim, Youngmi

    2014-06-21

    A new, water-soluble BODIPY dye 1, bearing sulfonate groups at the 2- and 6-positions was found to be a sensitive and selective fluorescent probe for the detection of HOCl/OCl(-) in aqueous buffer solution. The probe, which displays extremely weak fluorescence owing to efficient singlet excited state quenching by photoinduced electron transfer (PeT) from an electron-rich catechol group at a meso-position, responds to HOCl/OCl(-) through a dramatic enhancement of its fluorescence intensity.

  5. Review of methods and measurements of selected hydrophobic organic contaminant aqueous solubilities, vapor pressures, and air-water partition coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Bamford, H.A.; Baker, J.E.; Poster, D.L.

    1998-03-01

    Aqueous solubilities, vapor pressures, and Henry`s law constants for a wide range of organic contaminants of environmental interest are presented. Specifically, a discussion of methods used to measure these physical constants and resulting measurements are provided in an effort to examine the scope of physical constants reported in the scientific literature. Physical constants reviewed include those for 40 PAHs, 14 chlorinated aliphatics, 149 PCBs, 12 chlorinated benzenes, 16 dioxins, 63 furans, and 29 agrochemicals (a total of 323 compounds) and overall a total of 1,605 values are listed.

  6. Carbon dioxide solubility in aqueous solutions of sodium chloride at geological conditions: Experimental results at 323.15, 373.15, and 423.15 K and 150 bar and modeling up to 573.15 K and 2000 bar

    Science.gov (United States)

    Zhao, Haining; Fedkin, Mark V.; Dilmore, Robert M.; Lvov, Serguei N.

    2015-01-01

    A new experimental system was designed to measure the solubility of CO2 at pressures and temperatures (150 bar, 323.15-423.15 K) relevant to geologic CO2 sequestration. At 150 bar, new CO2 solubility data in the aqueous phase were obtained at 323.15, 373.15, and 423.15 K from 0 to 6 mol kg-1 NaCl(aq) for the CO2-NaCl-H2O system. A γ - φ (activity coefficient - fugacity coefficient) type thermodynamic model is presented for the calculation of both the solubility of CO2 in the aqueous phase and the solubility of H2O in the CO2-rich phase for the CO2-NaCl-H2O system. Validation of the model calculations against literature data and other models (MZLL2013, AD2010, SP2010, DS2006, and OLI) show that the proposed model is capable of predicting the solubility of CO2 in the aqueous phase for the CO2-H2O and CO2-NaCl-H2O systems with a high degree of accuracy (AAD @gmail.com.

  7. Prediction of pH-dependent aqueous solubility of druglike molecules

    DEFF Research Database (Denmark)

    Hansen, Niclas Tue; Kouskoumvekaki, Irene; Jørgensen, Flemming Steen

    2012-01-01

    that have been trained on a druglike PHYSPROP subset of 4548 compounds. For the prediction of acid/base dissociation coefficients, the commercial tool Marvin has been used, following validation on a data set of 467 molecules from the PHYSPROP database. The best performing network for intrinsic solubility......, giving a mean RMSE of 0.79 log S-units. Finally, the combined model has been applied on profiling the solubility space at low pH of five large vendor libraries....

  8. Densities and solubilities of Glycylglycine and Glycyl-L-Alanine in Aqueous Electrolyte Solutions

    DEFF Research Database (Denmark)

    Breil, Martin Peter; Mollerup, Jørgen; Rudolph, E. Susanne J.

    2004-01-01

    is 1.74 and 4.78 mol/kg of water, respectively. The solubility of glycylglycine in salt solutions of NaCl, Na2SO4, and (NH4)(2)SO4 show a moderate salting-in effect. The solubility of glycyl-L-alanine show a minor or no salting-in effect at low salt concentrations and a moderate salting-out effect...

  9. Investigation and comparison of performance of effervescent and standard pneumatic atomizer intended for soluble aqueous coating.

    Science.gov (United States)

    Nielsen, Anne Flachs; Poul, Bertelsen; Kristensen, Henning Gjelstrup; Kristensen, Jakob; Hovgaard, Lars

    2006-01-01

    Effervescent atomizers belong to the group of internal mixing atomizers. The effervescent approach might be a potential alternative to traditional atomization techniques, e.g., for applications where low atomization air consumption is advantageous In this paper, performance of one proposed design of the effervescent atomizer is investigated and compared to that of a standard pneumatic atomizer. The purpose of the comparison is to evaluate the actual potential of the specific effervescent atomizer in pharmaceutical relevant aqueous coating applications. Aqueous solutions of Hypromellose 5 as well as Povidone K-90F were characterized in terms of rheological properties and surface tension. Solutions were atomized by means of a standard Schlick pneumatic atomizer as well as a customized inside-out type effervescent atomizer. Spray droplet size distributions were recorded by a Spraytec instrument. Increased shear viscosity in the range 24-836 mPa.s had a modest effect on spray mean diameters for pneumatic sprays of the Newtonian solutions of Hypromellose 5. In contrast, mean droplet diameters increased by a factor of 3-5 in pneumatic sprays of Povidone K-90F solutions 11-175 mPa.s in viscosity, where non-Newtonian behavior was observed. Further, sprays of all solutions of Povidone K-90F have considerably larger mean droplet size. The effervescent atomizer atomized low viscosity solutions of Povidone K-90F more efficiently than Hypromellose 5 solutions of corresponding shear viscosity. However, atomization of high viscosity Povidone K-90F results in a coarser spray than that of the corresponding Hypromellose 5 solution. Viscosity, visco-elasticity, and surface tension of solutions all seem to affect atomization efficiency. The pneumatic atomizer was not sensitive to changes in airflow above 8.4 kg/h and liquid flow only had a considerable effect at suboptimal air flows. In its current design the effervescent atomizer improved efficiency throughout the investigated range

  10. Biomolecule-assisted synthesis of highly stable dispersions of water-soluble copper nanoparticles.

    Science.gov (United States)

    Xiong, Jing; Wu, Xue-dong; Xue, Qun-ji

    2013-01-15

    Water-soluble and highly stable dispersions of copper nanoparticles were obtained using a biomolecule-assisted synthetic method. Dopamine was utilized as both reducing and capping agent in aqueous medium. The successful formation of DA-stabilized copper particles was demonstrated by ultraviolet-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), Zeta potential measurement, and Fourier transform infrared spectroscopy (FT-IR). The mechanism of dopamine on the effective reduction and excellent stability of copper nanoparticles was also discussed. This facile biomolecule-assisted technique may provide a useful tool to synthesize other nanoparticles that have potential application in biotechnology.

  11. High solubility of SO2: evidence in an intensive fog event measured in the NCP region, China

    Directory of Open Access Journals (Sweden)

    X. Tie

    2011-01-01

    Full Text Available A field experiment was conducted in a heavy SO2 pollution area located in north China plain (NCP. During the experiment, SO2 and other air pollutants, liquid water content (LWC of fog droplets, and basic meteorological parameters were measured. During the experiment, an intensive fog event occurred between 5 and 8 November 2009. During the fog period, the concentrations of SO2 showed a strong variability, and the variability was closely correlated to the appearances of fogs and LWC. For example, the averaged concentration of SO2 during the non-fog period was about 25 ppbv. By contrast, during the fog period, the concentration of SO2 reduced to about 4–7 ppbv. The large reduction of SO2 suggests that a majority of SO2 (about 70–80% had been converted from gas-phase to aqueous-phase, showing a high solubility of SO2. However, according to the value of Henry Law constant, the solubility of SO2 is modest, which cannot explain the measured large reduction of SO2. This study highlights that the aqueous reactions of SO2 in the droplets of fogs play important roles to enhance the solubility of SO2. To account for the effect of aqueous reactions on the solubility of SO2, an "effective" Henry Law constant of SO2 is proposed in this study. The study shows that without considering aqueous reactions of SO2 in fog droplets, the estimate of the partitioning of SO2 in droplets is significantly lower than the measured values. By contrast, when the "effective" Henry Law constant is applied in the calculation, the calculated SO2 concentrations are significantly improved, showing that the aqueous reactions of SO2 play important roles in controlling the solubility of SO2, and should be considered in model calculations.

  12. Aqueous solubilities of five N-(diethylaminothiocarbonyl)benzimido derivatives at T = 298.15 K.

    Science.gov (United States)

    Schröder, Bernd; Martins, Mónia A R; Coutinho, João A P; Pinho, Simão P

    2016-10-01

    N-(diethylaminothiocarbonyl)benzimido derivatives are polar multifunctional substances. A set of these compounds was synthesised by successive substitution on the enamine side, resulting in similar substances with different polarities, providing a set of model compounds with respect to the study of substituent effects on physico-chemical properties. Experimental aqueous solubility data, at T = 298.15 K, of N-(diethylaminothiocarbonyl)benzamidine, PhCNH2NCSNEt2 (1),N-(diethylaminothiocarbonyl)-N'-phenylbenzamidine, PhCNHPhNCSNEt2 (2), N-(diethylaminothiocarbonyl)-N'-monoethylbenzamidine, PhCNHEtNCSNEt2 (3), N-(diethylaminothiocarbonyl)-N',N'-diethylbenzamidine, PhCNEt2NCSNEt2 (4), and N-(diethylaminothiocarbonyl)benzimido ethylester, PhCOEtNCSNEt2 (5) were measured at T = 298.15 K. The obtained data are supplemented by COSMO-RS aqueous solubility predictions as well as other environmentally important partition coefficients. This information is shown in a two-dimensional chemical space diagram, providing indications about the compartment into which the bulk of the compounds is likely to concentrate. The expected quality of COSMO-RS predictions for this type of screening exercise is illustrated on a set of pesticides with established thermophysical property data.

  13. Equilibrium solubility of CO{sub 2} in aqueous solutions of 1-amino-2-propanol as function of concentration, temperature, and pressure

    Energy Technology Data Exchange (ETDEWEB)

    Rebolledo-Morales, Miguel Angel; Rebolledo-Libreros, Maria Esther [Instituto Mexicano del Petroleo, Direccion de Investigacion y Posgrado, Programa de Ingenieria Molecular, Area de Investigacion de Termofisica, Eje Central Lazaro Cardenas Norte 152, 07730 Mexico, D.F. (Mexico); Trejo, Arturo, E-mail: atrejo@imp.m [Instituto Mexicano del Petroleo, Direccion de Investigacion y Posgrado, Programa de Ingenieria Molecular, Area de Investigacion de Termofisica, Eje Central Lazaro Cardenas Norte 152, 07730 Mexico, D.F. (Mexico)

    2011-05-15

    Research highlights: Gas solubility of CO{sub 2} in aqueous solutions of 1-amino-2-propanol was measured. Solubility increases as pressure and concentration of 1-amino-2-propanol increase. The Kent-Eisenberg model was used to correlate all the experimental results. Aqueous solutions of MIPA are an excellent alternative to use in gas purification. - Abstract: Using a dynamic method with recirculation of the vapour phase, experimental values for the gas solubility of carbon dioxide in aqueous solutions of 1-amino-2-propanol (MIPA) were measured at T = (313.15 and 393.15) K, over the pressure range of (0.2 to 2436.4) kPa. The concentrations of the studied aqueous MIPA solutions were (0.20, 0.30, 0.40, and 0.50) mass fraction. The results of gas solubility are given as the partial pressure of CO{sub 2}, p{sub CO{sub 2}}, against its mole ratio, {alpha}{sub CO{sub 2}} (mol CO{sub 2} {center_dot} mol{sup -1} MIPA), and its mole fraction, x{sub CO{sub 2}}. It is observed that the solubility of CO{sub 2} increases as the concentration of MIPA in solution increases, at a given temperature throughout the pressure range considered; also the solubility values increase, under constant temperature, as the pressure increases in the studied concentration range of MIPA. The physicochemical model of Kent and Eisenberg was used to correlate simultaneously all the experimental results of the solubility of CO{sub 2} in the studied aqueous solutions of MIPA. The model correlates satisfactorily the experimental results. The deviation for pressure was 96.9 kPa using 62 experimental solubility points. The solubility results of carbon dioxide presented in this work are compared with those reported in the literature for aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), and N-methyldiethanolamine (MDEA) and it is possible to conclude that the aqueous solutions of MIPA are an excellent alternative to use in gas purification processes, since the

  14. Assessment of the combined approach of N-alkylation and salt formation to enhance aqueous solubility of tertiary amines using bupivacaine as a model drug

    DEFF Research Database (Denmark)

    Nielsen, Anders Bach; Frydenvang, Karla Andrea; Liljefors, Tommy;

    2005-01-01

    Quaternary prodrug types of poorly water-soluble tertiary amines have been shown to exhibit significantly enhanced solubilities as compared to the parent amine. In the present study the combined effect of N-alkylation and salt formation to enhance aqueous solubility of tertiary amines have been...... tertiary amine (up to a factor of 3200 at pH 8). A moderate reduction in solubility with increasing length of the alkyl chain was observed for the iodide salts of the N-alkylated bupivacaine derivatives. In case of the N-methyl-bupivacaine derivative variation of the counterion had a significant impact...

  15. Solubilities of Toluene, Benzene and TCE in High-Biomass Systems

    Energy Technology Data Exchange (ETDEWEB)

    Barton, John W. [Battelle Eastern Science & Technology Center; Vodraska, Christopher D [ORNL; Flanary, Sandie A. [Oak Ridge National Laboratory (ORNL); Davison, Brian H [ORNL

    2008-01-01

    We report measurements of solubility limits for benzene, toluene, and TCE in systems that contain varying levels of biomass up to 0.13 g/mL. The solubility limit increased from 20 to 48 mM when biomass (in the form of yeast) was added to aqueous batch systems containing benzene. The toluene solubility limit increased from 4.9 to greater than 20 mM. For TCE, the solubility increased from 8 mM to more than 1000 mM. Solubility for TCE was most heavily impacted by biomass levels, changing by two orders of magnitude.

  16. Solubilities ,Densities and Refractive Indices of Rubidium Chloride or Cesium Chloride in Ethanol Aqueous Solutions at Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    ZHAO,Wen-Xia; HU,Man-Cheng; JIANG,Yu-Cheng; LI,Shu-Ni

    2007-01-01

    The data of solubilities.densities and refractive indices of rubidium chloride or cesium chloride in the system C2H5OH-H2O were measured by using a simple accurate analytical method at different temperatures,with mass fractions of ethanol in the range of O to 1.0.In all cases,the presence of ethanol significantly reduced the solubility of rubidium chloride and cesium chloride in aqueous solution.The solubilities of the saturated solutions were fitted via polynomial equations as a function of the mass fraction of ethanol.The CsCl-C2H5OH-H2O temary system appeared in two liquid phases:alcoholic phase and water phase.when the mass fractions of ethanol were in the range of 10.37% to 49.59%at 35℃.Density and refractive index were also determined for the same ternary systems with varied unsaturated salt concentrations.Values for both experiment and theory were correlated with the salt concentrations and proportions of alcohol in the solutions.The equations proposed could also account for the saturated solutions.

  17. Thermodynamic Model for Solubility of TcO2•xH2O in Aqueous Oxalate System

    Energy Technology Data Exchange (ETDEWEB)

    Hess, Nancy J.; Qafoku, Odeta; Xia, Yuanxian; Moore, Dean A.; Felmy, Andrew R.

    2008-11-01

    The solubility of hydrous technetium (IV) oxide (TcO2•xH2O) was studied across a broad range of pH values extending from 1.5 to 10 and in oxalate concentrations from dilute (10-6 m) to complete saturation with respect to sodium bioxalate at lower pH values and to saturation with respect to sodium oxalate at higher pH values. The solubility was measured at very long equilibriation times (i.e. as long a 1000+ days). The thermodynamic modeling results show that the dominant species in solution must have at least one more hydroxyl moiety present in the complex (e.g. TcO(OH)Ox- versus TcOOx(aq)) than proposed by previous investigators. The inclusion of the single previously unidentified species TcO(OH)Ox- in our aqueous thermodynamic model explains a wider range of observed solubility data for TcO2•xH2O in the presence of oxalate and over a broad range of pH values. Inclusion of this species is also supported by the recently proposed thermodynamic data for the TcO(OH)+ hydrolysis species which shows an enhanced stability for this species at pH values as low as one.

  18. Method for separating water soluble organics from a process stream by aqueous biphasic extraction

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, D.J.; Mego, W.A.

    1999-09-07

    A method for separating water-miscible organic species from a process stream by aqueous biphasic extraction is provided. An aqueous biphase system is generated by contacting a process stream comprised of water, salt, and organic species with an aqueous polymer solution. The organic species transfer from the salt-rich phase to the polymer-rich phase, and the phases are separated. Next, the polymer is recovered from the loaded polymer phase by selectively extracting the polymer into an organic phase at an elevated temperature, while the organic species remain in a substantially salt-free aqueous solution. Alternatively, the polymer is recovered from the loaded polymer by a temperature induced phase separation (cloud point extraction), whereby the polymer and the organic species separate into two distinct solutions. The method for separating water-miscible organic species is applicable to the treatment of industrial wastewater streams, including the extraction and recovery of complexed metal ions from salt solutions, organic contaminants from mineral processing streams, and colorants from spent dye baths.

  19. Method for separating water soluble organics from a process stream by aqueous biphasic extraction

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, David J. (Naperville, IL); Mego, William A. (Naperville, IL)

    1999-01-01

    A method for separating water-miscible organic species from a process stream by aqueous biphasic extraction is provided. An aqueous biphase system is generated by contacting a process stream comprised of water, salt, and organic species with an aqueous polymer solution. The organic species transfer from the salt-rich phase to the polymer-rich phase, and the phases are separated. Next, the polymer is recovered from the loaded polymer phase by selectively extracting the polymer into an organic phase at an elevated temperature, while the organic species remain in a substantially salt-free aqueous solution. Alternatively, the polymer is recovered from the loaded polymer by a temperature induced phase separation (cloud point extraction), whereby the polymer and the organic species separate into two distinct solutions. The method for separating water-miscible organic species is applicable to the treatment of industrial wastewater streams, including the extraction and recovery of complexed metal ions from salt solutions, organic contaminants from mineral processing streams, and colorants from spent dye baths.

  20. The solubility of carbon dioxide in aqueous N-methyldiethanolamine solutions

    NARCIS (Netherlands)

    Huttenhuis, P. J. G.; Agrawal, N. J.; Solbraa, E.; Versteeg, G. F.

    2008-01-01

    In this study the electrolyte equation of state as proposed by Solbraa [E. Solbraa, Equilibrium and non-equilibrium thermodynamics of natural gas processing, Ph.D. thesis Norwegian University of Science and Technology, 2002] was systematically studied and improved to describe the solubility of carbo

  1. On the use of differential solubility in aqueous ethanol solutions to narrow the DP range of food-grade starch hydrolysis products.

    Science.gov (United States)

    Balto, Amy S; Lapis, Trina J; Silver, Rachel K; Ferreira, Andrew J; Beaudry, Christopher M; Lim, Juyun; Penner, Michael H

    2016-04-15

    Considerable research is focused on understanding the functionality of starch hydrolysis products (SHP) consisting of glucose, maltose, maltooligosaccharides (MOS), and maltopolysaccharides (MPS). A confounding factor in this research is the high molecular dispersity of commercially available SHP. The study presented herein characterizes a flexible fractionation approach for lowering the dispersity of such products. This was accomplished by fractionating a corn syrup solids (CSS) preparation based on the differential solubility of its component saccharides in aqueous-ethanol solutions. Products obtained from selected fractionations were characterized with respect to degree of polymerization (DP; liquid chromatography), dextrose equivalency (reducing sugar assays), and prevalence of branching (NMR). Glucose and maltose were preferentially removed from CSS using high (⩾90%) ethanol extractants. Preparations with relatively narrow ranges of MOS, lower DP MPS, and higher DP MPS were obtained through repetitive 70%-ethanol extractions. Linear, as opposed to branched, MOS and MPS were preferentially extracted under all conditions tested.

  2. What Is the Mechanism Behind Increased Permeation Rate of a Poorly Soluble Drug from Aqueous Dispersions of an Amorphous Solid Dispersion?

    DEFF Research Database (Denmark)

    Frank, K. J.; Westedt, U.; Rosenblatt, K. M.

    2014-01-01

    Our aim was to explore the influence of micelles and microparticles emerging in aqueous dispersions of amorphous solid dispersions (ASDs) on molecular/apparent solubility and Caco-2 permeation. The ASD, prepared by hot-melt extrusion, contained the poorly soluble model drug ABT-102, a hydrophilic...... polymer, and three surfactants. Aqueous dispersions of the ASD were investigated at two concentrations, one above and one close to the critical micelle concentration of the surfactants blend in the extrudate. Micelles were detected at the higher concentration and no micelles at the lower concentration...

  3. Solubility and solubilizing capabilities of aqueous solutions of Extractum Taraxaci e radix cum herba aqu. siccum in light of selected values of general Hildebrand-Scatchard-Fedors theory of solubility

    Directory of Open Access Journals (Sweden)

    Marczyński Zbigniew

    2016-12-01

    Full Text Available Introduction: The general Hildebrand-Scatchard theory of solubility supplemented by Fedors’ solubility parameter −δ12$- \\delta ^{{1 \\over 2}} $ was used to estimate the real solubility by −log x2 (log of the mole fraction of phytochemicals contained in Ext. Taraxaci e radix cum herba aqu. siccum. Surface activity of aqueous solution of extracts was determined and quantified – solubilizing capabilities of solutions of cexp. ≥cmc in relation to cholesterol particle size of Ø=1.00 mm, as well as of ketoprofen were defined.

  4. Six global and local QSPR models of aqueous solubility at pH = 7.4 based on structural similarity and physicochemical descriptors.

    Science.gov (United States)

    Raevsky, O A; Grigorev, V Y; Polianczyk, D E; Raevskaja, O E; Dearden, J C

    2017-08-01

    Aqueous solubility at pH = 7.4 is a very important property for medicinal chemists because this is the pH value of physiological media. The present work describes the application of three different methods (support vector machine (SVM), random forest (RF) and multiple linear regression (MLR)) and three local quantitative structure-property relationship (QSPR) models (regression corrected by nearest neighbours (RCNN), arithmetic mean property (AMP) and local regression property (LoReP)) to construct stable QSPRs with clear mechanistic interpretation. Our data set contained experimental values of aqueous solubility at pH = 7.4 of 387 chemicals (349 in the training set and 38 in the test set including 16 own measurements). The initial descriptor pool contained 210 physicochemical descriptors, calculated from the HYBOT, DRAGON, SYBYL and VolSurf+ programs. Six QSPRs with good statistics based on fundamentals of aqueous solubility and optimization of descriptor space were obtained. Those models have an RMSE close to experimental error (0.70), and are amenable to physical interpretation. The QSPR models developed in this study may be useful for medicinal chemists. Global MLR, RF and SVM models may be valuable for consideration of common factors that influence solubility. The RCNN, AMP and LoReP local models may be helpful for the optimization of aqueous solubility in small sets of related chemicals.

  5. Boronic acid-containing aminopyridine- and aminopyrimidinecarboxamide CXCR1/2 antagonists: Optimization of aqueous solubility and oral bioavailability.

    Science.gov (United States)

    Schuler, Aaron D; Engles, Courtney A; Maeda, Dean Y; Quinn, Mark T; Kirpotina, Liliya N; Wicomb, Winston N; Mason, S Nicholas; Auten, Richard L; Zebala, John A

    2015-09-15

    The chemokine receptors CXCR1 and CXCR2 are important pharmaceutical targets due to their key roles in inflammatory diseases and cancer progression. We have previously identified 2-[5-(4-fluoro-phenylcarbamoyl)-pyridin-2-ylsulfanylmethyl]-phenylboronic acid (SX-517) and 6-(2-boronic acid-5-trifluoromethoxy-benzylsulfanyl)-N-(4-fluoro-phenyl)-nicotinamide (SX-576) as potent non-competitive boronic acid-containing CXCR1/2 antagonists. Herein we report the synthesis and evaluation of aminopyridine and aminopyrimidine analogs of SX-517 and SX-576, identifying (2-{(benzyl)[(5-boronic acid-2-pyridyl)methyl]amino}-5-pyrimidinyl)(4-fluorophenylamino)formaldehyde as a potent chemokine antagonist with improved aqueous solubility and oral bioavailability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Synthesis of a highly water-soluble acacetin prodrug for treating experimental atrial fibrillation in beagle dogs.

    Science.gov (United States)

    Liu, Hui; Wang, Ya-Jing; Yang, Lei; Zhou, Mei; Jin, Man-Wen; Xiao, Guo-Sheng; Wang, Yan; Sun, Hai-Ying; Li, Gui-Rong

    2016-05-10

    We previously reported that duodenal administration of the natural flavone acacetin can effectively prevent the induction of experimental atrial fibrillation (AF) in canines; however, it may not be used intravenously to terminate AF due to its poor water-solubility. The present study was to design a water-soluble prodrug of acacetin and investigate its anti-AF effect in beagle dogs. Acacetin prodrug was synthesized by a three-step procedure. Aqueous solubility, bioconversion and anti-AF efficacy of acacetin prodrug were determined with different methodologies. Our results demonstrated that the synthesized phosphate sodium salt of acacetin prodrug had a remarkable increase of aqueous solubility in H2O and clinically acceptable solution (5% glucose or 0.9% NaCl). The acacetin prodrug was effectively converted into acacetin in ex vivo rat plasma and liver microsome, and in vivo beagle dogs. Intravenous infusion of acacetin prodrug (3, 6 and 12 mg/kg) terminated experimental AF without increasing ECG QTc interval in beagle dogs. The intravenous LD50 of acacetin prodrug was 721 mg/kg in mice. Our preclinical study indicates that the synthesized acacetin prodrug is highly water-soluble and safe; it effectively terminates experimental AF in beagle dogs and therefore may be a promising drug candidate for clinical trial to treat patients with acute AF.

  7. Chemical Potentials, Activity Coefficients, and Solubility in Aqueous NaCl Solutions: Prediction by Polarizable Force Fields.

    Science.gov (United States)

    Moučka, Filip; Nezbeda, Ivo; Smith, William R

    2015-04-14

    We describe a computationally efficient molecular simulation methodology for calculating the concentration dependence of the chemical potentials of both solute and solvent in aqueous electrolyte solutions, based on simulations of the salt chemical potential alone. We use our approach to study the predictions for aqueous NaCl solutions at ambient conditions of these properties by the recently developed polarizable force fields (FFs) AH/BK3 of Kiss and Baranyai (J. Chem. Phys. 2013, 138, 204507) and AH/SWM4-DP of Lamoureux and Roux (J. Phys. Chem. B 2006, 110, 3308 - 3322) and by the nonpolarizable JC FF of Joung and Cheatham tailored to SPC/E water (J. Phys. Chem. B 2008, 112, 9020 - 9041). We also consider their predictions of the concentration dependence of the electrolyte activity coefficient, the crystalline solid chemical potential, the electrolyte solubility, and the solution specific volume. We first highlight the disagreement in the literature concerning calculations of solubility by means of molecular simulation in the case of the JC FF and provide strong evidence of the correctness of our methodology based on recent independently obtained results for this important test case. We then compare the predictions of the three FFs with each other and with experiment and draw conclusions concerning their relative merits, with particular emphasis on the salt chemical potential and activity coefficient vs concentration curves and their derivatives. The latter curves have only previously been available from Kirkwood-Buff integrals, which require approximate numerical integrations over system pair correlation functions at each concentration. Unlike the case of the other FFs, the AH/BK3 curves are nearly parallel to the corresponding experimental curves at moderate and higher concentrations. This leads to an excellent prediction of the water chemical potential via the Gibbs-Duhem equation and enables the activity coefficient curve to be brought into excellent agreement

  8. High charge carrier mobility and efficient charge separation in highly soluble perylenetetracarboxyl-diimides

    NARCIS (Netherlands)

    Günbaş, D.D.; Xue, C.; Patwardhan,S.; Fravventura, M.C.; Zhang, H.; Jager, W.F.; Sudhölter, E.J.R.; Laurens D. A.; Siebbeles, L.D.A.; Savenije, T.J.; Jin, S.; Grozema, F.C.

    2014-01-01

    In this communication we report on the synthesis and charge mobility of highly soluble perylenebisimid derivatives.We show that introduction of alkylester side chains results in compounds combining a high solubility with charge mobilities up to 0.22 cm2 V_1 s_1. These materials are therefore interes

  9. Impact of polymer conformation on the crystal growth inhibition of a poorly water-soluble drug in aqueous solution.

    Science.gov (United States)

    Schram, Caitlin J; Beaudoin, Stephen P; Taylor, Lynne S

    2015-01-01

    Poor aqueous solubility is a major hindrance to oral delivery of many emerging drugs. Supersaturated drug solutions can improve passive absorption across the gastrointestinal tract membrane as long as crystallization can be inhibited, enhancing the delivery of such poorly soluble therapeutics. Polymers can inhibit crystallization and prolong supersaturation; therefore, it is desirable to understand the attributes which render a polymer effective. In this study, the conformation of a polymer adsorbed to a crystal surface and its impact on crystal growth inhibition were investigated. The crystal growth rate of a poorly soluble pharmaceutical compound, felodipine, was measured in the presence of hydroxypropyl methylcellulose acetate succinate (HPMCAS) at two different pH conditions: pH 3 and pH 6.8. HPMCAS was found to be a less effective growth rate inhibitor at pH 3, below its pKa. It was expected that the ionization state of HPMCAS would most likely influence its conformation at the solid-liquid interface. Further investigation with atomic force microscopy (AFM) revealed significant differences in the conformation of HPMCAS adsorbed to felodipine at the two pH conditions. At pH 3, HPMCAS formed coiled globules on the surface, whereas at pH 6.8, HPMCAS adsorbed more uniformly. Thus, it appeared that the reduced effectiveness of HPMCAS at pH 3 was directly related to its conformation. The globule formation leaves many felodipine growth sites open and available for growth units to attach, rendering the polymer less effective as a growth rate inhibitor.

  10. Ternary system of dihydroartemisinin with hydroxypropyl-β-cyclodextrin and lecithin: simultaneous enhancement of drug solubility and stability in aqueous solutions.

    Science.gov (United States)

    Wang, Dan; Li, Haiyan; Gu, Jingkai; Guo, Tao; Yang, Shuo; Guo, Zhen; Zhang, Xueju; Zhu, Weifeng; Zhang, Jiwen

    2013-09-01

    The purpose of this study was to simultaneously improve the solubility and stability of dihydroartemisinin (DHA) in aqueous solutions by a ternary cyclodextrin system comprised of DHA, hydroxypropyl-β-cyclodextrin (HP-β-CD) and a third auxiliary substance. Solubility and phase solubility studies were carried out to evaluate the solubilizing efficiency of HP-β-CD in association with various auxiliary substances. Then, the solid binary (DHA-HP-β-CD or DHA-lecithin) and ternary systems were prepared and characterized by Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC) and power X-ray diffraction (PXRD). The effect of the ternary system on the solubility, dissolution and stability of DHA in aqueous solutions was also investigated. As a result, the soybean lecithin was found to be the most promising third component in terms of solubility enhancement. For the solid characterization, the disappearance of the drug crystallinity indicated the formation of new solid phases, implicating the formation of the ternary system. The dissolution rate of the solid ternary system was much faster than that of the drug alone and binary systems. Importantly, compared with binary systems, the ternary system showed a significant improvement in the stability of DHA in Hank's balanced salt solutions (pH 7.4). The solubility and stability of DHA in aqueous solutions were simultaneously enhanced by the ternary system, which might be attributed to the possible formation of a ternary complex. For the ternary interactions, results of molecular docking studies further indicated that the lecithin covered the top of the wide rim of HP-β-CD and surrounded around the peroxide bridging of DHA, providing the possibility for the ternary complex formation. In summary, the ternary system prepared in our study, with simultaneous enhancement of DHA solubility and stability in aqueous solutions, might have an important pharmaceutical potential in the development of a better

  11. Controlled poorly soluble drug release from solid self-microemulsifying formulations with high viscosity hydroxypropylmethylcellulose.

    Science.gov (United States)

    Yi, Tao; Wan, Jiangling; Xu, Huibi; Yang, Xiangliang

    2008-08-07

    The objective of this work was the development of a controlled release system based on self-microemulsifying mixture aimed for oral delivery of poorly water-soluble drugs. HPMC-based particle formulations were prepared by spray drying containing a model drug (nimodipine) of low water solubility and hydroxypropylmethylcellulose (HPMC) of high viscosity. One type of formulations contained nimodipine mixed with HPMC and the other type of formulations contained HPMC and nimodipine dissolved in a self-microemulsifying system (SMES) consisting of ethyl oleate, Cremophor RH 40 and Labrasol. Based on investigation by transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray powder diffraction, differences were found in the particle structure between both types of formulations. In vitro release was performed and characterized by the power law. Nimodipine release from both types of formulations showed a controlled release profile and the two power law parameters, n and K, correlated to the viscosity of HPMC. The parameters were also influenced by the presence of SMES. For the controlled release solid SMES, oil droplets containing dissolved nimodipine diffused out of HPMC matrices following exposure to aqueous media. Thus, it is possible to control the in vitro release of poorly soluble drugs from solid oral dosage forms containing SMES.

  12. Thermodynamic origin of the solubility profile of drugs showing one or two maxima against the polarity of aqueous and nonaqueous mixtures: niflumic acid and caffeine.

    Science.gov (United States)

    Bustamante, Pilar; Navarro, J; Romero, S; Escalera, B

    2002-03-01

    The purpose of this work was to investigate the origin of the different solubility profiles of drugs against the polarity of solvent mixtures with a common cosolvent. Niflumic acid and caffeine where chosen as model drugs. The solubilities were measured at five or six temperatures in aqueous (ethanol-water) and nonaqueous (ethyl acetate-ethanol) mixtures. The enthalpies of solution were obtained at the harmonic mean of the experimental temperature. Solid phase changes were analyzed using differential scanning calorimetry and thermomicroscopy. A single solubility maximum was obtained for niflumic acid against the solubility parameter of both mixtures that is not related to solid phase changes. In contrast, caffeine displays two maxima and anhydrous-hydrate transition occurs at the solubility peak in the amphiprotic mixture. The apparent enthalpies of solution of both drugs show endothermic maxima against solvent composition that are related to hydrophobic hydration. A general explanation for the cosolvent action in aqueous mixtures is proposed. The dominant mechanism shifts from entropy to enthalpy at a certain cosolvent ratio dependent on the hydrophobicity and the solubility parameter of the drug. Niflumic acid and caffeine show enthalpy-entropy compensation in ethanol-water, and this relationship is demonstrated for the first time in nonaqueous mixtures. The results support that enthalpy-entropy compensation is a general effect for the solubility of drugs in solvent mixtures. The shape of the solubility curves is correlated with the compensation plots. The solubility peaks separate different enthalpy-entropy relationships that also differentiate the solubility behavior of the hydrate and the anhydrous forms of caffeine. Copyright 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association.

  13. Solubility study of nickel ferrite in boric acid using a flow-through autoclave system under high temperature and high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Joon; Choi, Ke Chon; Ha, Yeong Keong [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-04-15

    The solubility of nickel ferrite in an aqueous solution of boric acid was studied by varying the pH at the temperatures ranging from 25 .deg. C to 320 .deg. C. A flow-through autoclave system was specially designed and fabricated to measure the solubility of Fe in hydrothermal solutions under high temperature and pressure. The performance of this flow-through system was directly compared with the conventional static state technique using a batch-type autoclave system. The stability of fluid velocity for the flow-through autoclave system was verified prior to the solubility measurement. The influence of chemical additives, such as boric acid and H2, on the solubility of nickel ferrite was also evaluated.

  14. Study of Bovine Serum Albumin Solubility in Aqueous Solutions by Intrinsic Viscosity Measurements

    Directory of Open Access Journals (Sweden)

    Martin Alberto Masuelli

    2013-01-01

    Full Text Available The behavior of bovine serum albumin (BSA in water is scarcely studied, and the thermodynamic properties arising from the experimental measurements have not been reported. Intrinsic viscosity measurements are very useful in assessing the interaction between the solute and solvent. This work discussed in a simple determination of the enthalpy of BSA in aqueous solution when the concentration ranges from 0.2 to 36.71% wt. and the temperature from 35 to 40°C. The relationship between the concentration and intrinsic viscosity is determined according to the method of Huggins. The temperature increase reduces the ratio between inherent viscosity and concentration (ηi/c. This is reflected in the Van't Hoff curve. Furthermore, this work proposes hydrodynamic cohesion value as an indicator of the degree of affinity of protein with water and thermodynamic implications in conformational changes.

  15. Aqueous solubility and Daphnia magna chronic toxicity of di(2-ethylhexyl) adipate.

    Science.gov (United States)

    Robillard, K A; Dufresne, D L; Gorsuch, J W; Stubblefield, W A; Staples, C A; Parkerton, T F

    2008-06-01

    A water solubility of 5.5 (+/-0.22) microg/L for di(2-ethylhexyl) adipate (DEHA) was measured using the slow-stir method. This value is consistent with computer estimations and over two orders of magnitude lower than that previously determined using the shake-flask method. We performed a 21-day chronic Daphnia magna limit test at an average exposure of 4.4 microg/L in laboratory diluent water to avoid insoluble test material and avoid physical entrapment. One hundred percent of the DEHA-treated organisms survived compared to 90% survival in both the controls and solvent controls. Mean neonate reproduction was 152, 137, and 148 and mean dry weight per surviving female was 0.804, 0.779, and 0.742 mg in the DEHA treatment, control, and solvent control, respectively. No adverse effects were observed.

  16. Chemistry of Secondary Metabolites (Production, Properties, Biological Activity, etc.: Solubility Study of the Interaction between Pamam G-3 Dendrimer and 5 Fluorouracil in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    B. PALECZ

    2014-06-01

    Full Text Available Poly(amidoamine dendrimers (PAMAM are polymeric macromolecules that can find their use as carriers of small ligand molecules such as cosmetics and drugs. 5- Fluorouracil is a potent oncological drug, whose usage is limited because of its relatively high toxicity.The surface and internal layer groups in PAMAM dendrimer belonging to the third (G3 generation create an open-type structure, which facilitate small ligand molecules to bind with them.The formation equilibrium of PAMAM G3 dendrimer complex with an oncologic drug such as 5 fluorouracil (FU in water at room temperature was examined. Using the results of the drug solubility in dendrimer solutions, the maximal number of drug molecules in the dendrimer-drug complex was evaluated. Solubility results show that PAMAM G3 dendrimer can transfer tens 5 fluorouracil molecules in aqueous solution.This research work was funded from the Polish budget appropriations for science in the years 2013-2015, project number IP2012 022372.

  17. SYNTHESIS AND CHARACTERIZATION OF HIGHLY SOLUBLE AROMATIC POLYIMIDES

    Institute of Scientific and Technical Information of China (English)

    Xiao-hua Huang; Wei Huang; Yong-feng Zhou; De-yue Yan

    2011-01-01

    Two highly soluble aromatic polyimides were synthesized successfully from a diamine with two tert-butyl groups (MBTBA) and dianhydrides with a thioether or sulfone moiety (DTDA and DSDA). Both of them showed excellent solubility in common solvents such as chloroform, tetrahydrofuran and dioxane at the room temperature. The numberaverage molecular weight was 6.0 × 104 and 8.3 × 104 according to gel permeation chromatography relative to a polystyrene standard, and the polydispersity index was 1.80 and 1.82 respectively. The glass-transition temperatures of them were 286℃and 314℃ (or 315℃ and 358℃) respectively, as measured by differential scanning calorimetry (or dynamic mechanical analysis). The 5% weight loss temperature of both was near 490℃ in N2 by thermogravimetric analysis. These results indicated that the tert-butyl pendent groups reduced the interactions among polymer chains and the thioether or sulfone moiety was flexible which may improve their solubility in conventional organic solvents without the loss of thermal stability.Transparent and flexible films of the two polyimides were obtained via solution casting. The MBTBA-DTDA membrane had higher storage moduli than those of the MBTBA-DSDA membrane.

  18. Predicting the Potentials, Solubilities and Stabilities of Metal-Acetylacetonates for Non-Aqueous Redox Flow Batteries Using Density Functional Theory Calculations.

    Energy Technology Data Exchange (ETDEWEB)

    Kucharyson, J. F.; Cheng, L.; Tung, S. O.; Curtiss, L. A.; Thompson, L. T.

    2017-07-14

    New active materials are needed to improve the performance and reduce the cost of non-aqueous redox flow batteries (RFBs) for grid-scale energy storage applications. Efforts to develop better performing materials, which have largely been empirical, would benefit from a better understanding of relationships between structural, electronic and RFB-relevant functional properties. This paper focuses on metal-acetylacetonates, a class of metal coordination complexes that has shown promise for use in RFBs, and describes correlations between their experimentally measured standard potentials, solubilities, and stabilities (cycle lifes), and selected chemical, structural and electronic properties determined from Density Functional Theory (DFT) calculations. The training set consisted of 16 complexes including 5 different metals and 11 different substituents on the acetylacetonate ligand. Standard potentials for those compounds were calculated and are in good agreement with experimentally measured results. A predictive equation based on the solvation energies and dipole moments, two easily computed properties, reasonably modeled the experimentally determined solubilities. Importantly, we were able to identify a descriptor for the stability of acetylacetonates. The experimentally determined stability, quantified as the cycle life to a given degree of degradation, correlated with the percentage of the highest occupied (HOMO) or lowest unoccupied molecular orbital (LUMO) on the metal of the complex. This percentage is influenced by the degree of ligand innocence (irreducibility), and complexes with the most innocent ligands yielded the most stable redox reactions. To this end, VO(acetylacetonate)(2) and Fe(acetylacetonate)(3), with nearly 80% of the HOMO and LUMO on the metal, possessed the most stable oxidation and reduction half-reactions, respectively. The structure-function relationships and correlations presented in this paper could be used to predict new, highly soluble

  19. Photoprotection of vitamins in skimmed milk by an aqueous soluble lycopene-gum Arabic microcapsule.

    Science.gov (United States)

    Montenegro, Mariana A; Nunes, Itaciara L; Mercadante, Adriana Z; Borsarelli, Claudio D

    2007-01-24

    Riboflavin (Rf)-mediated photosensitized degradation of vitamins A and D3 in skimmed milk under illumination with a white fluorescence lamp was studied by using the HPLC technique. The photosensitized degradation of both vitamins followed first-order kinetics, and the temperature effect on the observed photodegradation rate constant allowed the determination of the activation energy Ea as being 4 and 16 kcal/mol for vitamins A and D3, respectively. The addition of lycopene microencapsulated by spray-drying with a gum arabic-sucrose (8:2) mixture (MIC) produced a reduction of ca. 45% in the photosensitized degradation rate of both vitamins. Front-face fluorescence experiments showed the same photoprotection factor in the degradation of Rf itself, indicating that the photodegradation mechanism involved Rf-mediated reactive species, such as the excited triplet state of Rf, 3Rf*, and/or singlet molecular oxygen, 1O2. The interaction of both 3Rf* and 1O2 with MIC was evaluated in aqueous solutions by using laser-induced time-resolved absorption or emission spectroscopy, and the contribution of an inner-filter effect in the presence of MIC in skimmed milk was evaluated by diffuse reflectance spectroscopy. The main operating mechanism of photoprotection is due to the deactivation of 3Rf* by the proteic component of gum arabic; thus, gum arabic based microcapsules could be used to improve the photostability of milk during its storage and/or processing under light.

  20. Implementation of equilibrium aqueous speciation and solubility (EQ3 type) calculations into Cantera for electrolyte solutions.

    Energy Technology Data Exchange (ETDEWEB)

    Moffat, Harry K.; Jove-Colon, Carlos F.

    2009-06-01

    In this report, we summarize our work on developing a production level capability for modeling brine thermodynamic properties using the open-source code Cantera. This implementation into Cantera allows for the application of chemical thermodynamics to describe the interactions between a solid and an electrolyte solution at chemical equilibrium. The formulations to evaluate the thermodynamic properties of electrolytes are based on Pitzer's model to calculate molality-based activity coefficients using a real equation-of-state (EoS) for water. In addition, the thermodynamic properties of solutes at elevated temperature and pressures are computed using the revised Helgeson-Kirkham-Flowers (HKF) EoS for ionic and neutral aqueous species. The thermodynamic data parameters for the Pitzer formulation and HKF EoS are from the thermodynamic database compilation developed for the Yucca Mountain Project (YMP) used with the computer code EQ3/6. We describe the adopted equations and their implementation within Cantera and also provide several validated examples relevant to the calculations of extensive properties of electrolyte solutions.

  1. Use of an aqueous soluble tetrazolium/formazan assay for cell growth assays in culture.

    Science.gov (United States)

    Cory, A H; Owen, T C; Barltrop, J A; Cory, J G

    1991-07-01

    A new tetrazolium analog of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) was evaluated as a substitute for MTT in the microculture screening assay for in vitro cell growth. This new tetrazolium compound, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium, inner salt (MTS), in the presence of phenazine methosulfate (PMS), gave a water-soluble formazan product that had an absorbance maximum at 490-500 nm in phosphate-buffered saline. The amount of colored product formed was proportional to the number of cells and the time of incubation of the cells with MTS/PMS. MTS/PMS was reactive in all the cell lines tested which included mouse leukemia L1210 cells, mouse Ehrlich tumor cells, mouse 3T3 fibroblasts, and human colon tumor cells (HT-29). HT-29 and 3T3 fibroblasts reduced MTS/PMS more efficiently than they reduced MTT. Comparable to the amount of product formed from MTT, MTS/PMS gave excellent product formation. The IC50 value for pyrazoloimidazole obtained using MTS/PMS was 200 microM; for 5-fluoro-2'-deoxyuridine, the IC50 value was 0.9 nM. These values compared very favorably with the IC50 values obtained by direct cell counts. Further, the same IC50 values were obtained when the absorbances of the formazan product in the 96-well plates were determined after different times of incubation.

  2. Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

    Science.gov (United States)

    Rizzi, Vito; Matera, Sergio; Semeraro, Paola; Fini, Paola

    2016-01-01

    Summary Since several years the inclusion of organic compounds (guests) within the hydrophobic cavity (host) of cyclodextrins (CDs) has been the subject of many investigations. Interestingly, the formation of inclusion complexes could affect the properties of the guest molecules and, for example, the influence of the delivery system can be a method to improve/change the photochemical behavior of the guest. In particular, very recent studies have shown the protective role of CDs preventing the degradation of the encapsulated guest. Starting from this consideration, in this work, only the structure and complexation mode of the inclusion complexes involving 4-thiothymidine (S4TdR, a known photosensitizer) and five CDs, namely 2-hydroxypropyl-α-cyclodextrin (2-HP-α-CD), 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (2-HP-γ-CD), heptakis-(2,6-di-O-methyl)-β-cyclodextrin (DIMEB CD) and heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB CD) were investigated by different spectroscopic techniques (UV–vis, FTIR–ATR, 1H NMR) and cyclic voltammetry analysis (CV). This work is necessary for a prospective research on the photoreactivity of S4TdR in aqueous environment and in the presence of CDs to prevent its degradation under irradiation. UV–vis, FTIR–ATR and CV measurements suggested the formation of supramolecular structures involving the employed CDs and mainly the pyrimidine ring of S4TdR. 1H NMR analyses confirmed such indication, unveiling the presence of inclusion complexes. The strongest and deepest interactions were suggested when TRIMEB and DIMEB CDs were studied. The S4TdR affinity towards CDs was also evaluated by using the Benesi–Hildebrand (B–H) equation at 25 °C employing CV and 1H NMR methods. The stoichiometry of the interaction was also inferred and it appears to be 1:1 for all examined CDs. PMID:27340447

  3. Use of an aqueous soluble tetrazolium/formazan assay to measure viability and proliferation of lymphokine-dependent cell lines.

    Science.gov (United States)

    Buttke, T M; McCubrey, J A; Owen, T C

    1993-01-04

    A new tetrazolium compound, MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt), has recently been described which in the presence of phenazine methosulfate (PMS) is reduced by living cells to yield a formazan product that can be assayed colorimetrically. An important advantage of MTS/PMS over other tetrazolium dyes (e.g., MTT) is the aqueous solubility of the reduced formazan product which eliminates the need for detergent solubilization or organic solvent extraction steps. Its advantages over XTT/PMS, another tetrazolium which yields a water-soluble formazan product, include the absorbance range of color produced (515-580 nm as opposed to 450 nm), the rapidity of color development, and the storage stability of the MTS/PMS reagent solution. In the present study, MTS/PMS was used to assay viability and proliferation of the IL-2-dependent HT-2 and CTLL-2 cell lines and the IL-3-dependent FDC-P1 and FL5.12 cell lines. With each cell line, the amount of formazan product was time-dependent and proportional to the number of viable cells. Furthermore, with both HT-2 and CTLL-2 cells it was found that cultures could be simultaneously labeled with MTS/PMS and [3H]thymidine, with relatively little effect of the dye on uptake of the latter. This feature was further capitalized upon in studies with FDC-P1 cells, in which the co-addition of MTS/PMS and [3H]thymidine was used to distinguish between cell viability and proliferation.

  4. High-temperature and high-pressure water solubility in ethylbenzene to 200°C and 1 kbar and the acetic acid effect

    Science.gov (United States)

    Guillaume, Damien; Tkachenko, Sergey; Dubessy, Jean; Pironon, Jacques

    2001-10-01

    Water solubility in hydrocarbon systems is of great interest for deep oil fields. A new autoclave has been designed to measure phase equilibria in water-hydrocarbon systems up to 400°C and 1.5 kbar. It has been applied for the measurement of water solubility in ethylbenzene with or without acetic acid to 200°C and 1 kbar in the two-phase field. Water solubility was measured by the Karl Fisher method. The acetic acid concentration was measured by FT-IR microspectroscopy. Both the experimental procedure and analytical techniques were validated by showing the consistency of our data with those of Heidman et al. (;High-temperature mutual solubilities of hydrocarbons and water,; AIChE J.31, 376-384, 1995) along the liquid-liquid-vapor curve. At constant pressure, the solubility of water in ethylbenzene increases significantly with temperature. On the other hand, at constant temperature, the solubility of water is constant to 1 kbar at 100°C, and decreases slightly with pressure at 150 and 200°C. Data were regressed by the Krichevsky-Kasarnovsky equation to obtain estimates of the Henry's law constant and estimates of the molar volume of water at infinite dilution. Acetic acid increases the solubility of water in ethylbenzene and fractionates preferentially into the aqueous phase.

  5. Solubility and Surface Adsorption Characteristics of Metal Oxides to High Temperature

    Energy Technology Data Exchange (ETDEWEB)

    D.J. Wesolowski; M.L. Machesky; S.E. Ziemniak; C. Xiao; D.A. Palmer; L.M. Anovitz; P. Benezeth

    2001-05-04

    The interaction of high temperature aqueous solutions with mineral surfaces plays a key role in many aspects of fossil, geothermal and nuclear energy production. This is an area of study in which the subsurface geochemical processes that determine brine composition, porosity and permeability changes, reservoir integrity, and fluid flow rates overlap with the industrial processes associated with corrosion of metal parts and deposition of solids in pipes and on heat exchanger surfaces. The sorption of ions on mineral surfaces is also of great interest in both the subsurface and ''above ground'' regimes of power production, playing a key role in subsurface migration of contaminants (nuclear waste disposal, geothermal brine re-injection, etc.) and in plant operations (corrosion mitigation, migration of radioactive metals from reactor core to heat exchanger, etc.). In this paper, results of the solubility and surface chemistry of metal oxides relevant to both regimes are summarized.

  6. Synthetic Enantiopure Carbohydrate Polymers that are Highly Soluble in Water and Noncytotoxic.

    Science.gov (United States)

    Dane, Eric L; Chin, Stacy L; Grinstaff, Mark W

    2013-10-15

    The first synthesis of poly-amido-saccharides (PASs) from a galactose(gal)-derived β-lactam sugar monomer is reported. The polymers are prepared using a controlled anionic ring-opening polymerization and characterized by NMR, optical rotation, IR, and GPC. Galactose-derived PASs display high solubility in aqueous solutions and are noncytotoxic to HepG2, CHO, and HeLa cell lines. To evaluate whether gal-derived PASs are recognized by the gal-specific lectin present on human hepatocytes, cellular uptake of rhodamine-labeled polymers is assessed using flow cytometry and fluorescence microscopy. Based on these results, the polymers are taken into cells via endocytosis that is not dependent on the gal-specific receptor on hepatocytes. Neutral, hydrophilic polymers, such as gal-derived PASs, are desirable materials for a range of biomedical applications, such as drug delivery, surface passivation, and hydrogel formation.

  7. A Highly Efifcient and Selective Water-Soluble Bimetallic Catalyst for Hydrogenation of Chloronitrobenzene to Chloroaniline

    Institute of Scientific and Technical Information of China (English)

    Zhou Yafen; Yang Wenjuan; Zhou Limei; Wang Manman; Ma Xiaoyan

    2015-01-01

    Selective hydrogenation of chloronitrobenzene (CNB) to chloroaniline (CAN) catalyzed by water-soluble Ru/Pt bimetallic catalyst in an aqueous-organic biphasic system was studied. It was found that the catalytic activity increased ob-viously due to the addition of platinum. Ru/Pt bimetallic catalysts exhibited a strong synergistic effect when the molar ratio of Pt was in the range of 5%—80%. Under the mild conditions including a temperature of 25℃, a hydrogen pressure of 1.0 MPa and a Pt molar ratio of 20%, the conversion of p-chloronitrobenzene (p-CNB) reached 99.9%, with the selectivity to p-chloroaniline (p-CAN) equating to 99.4%. The Ru/Pt catalyst also showed high activity and selectivity for the hydrogena-tion of other chloro-and dichloro-nitrobenzenes with different substituted positions. In addition, the catalyst can be recycled ifve times without signiifcant loss of activity.

  8. What is the mechanism behind increased permeation rate of a poorly soluble drug from aqueous dispersions of an amorphous solid dispersion?

    Science.gov (United States)

    Frank, Kerstin J; Westedt, Ulrich; Rosenblatt, Karin M; Hölig, Peter; Rosenberg, Jörg; Mägerlein, Markus; Fricker, Gert; Brandl, Martin

    2014-06-01

    Our aim was to explore the influence of micelles and microparticles emerging in aqueous dispersions of amorphous solid dispersions (ASDs) on molecular/apparent solubility and Caco-2 permeation. The ASD, prepared by hot-melt extrusion, contained the poorly soluble model drug ABT-102, a hydrophilic polymer, and three surfactants. Aqueous dispersions of the ASD were investigated at two concentrations, one above and one close to the critical micelle concentration of the surfactants blend in the extrudate. Micelles were detected at the higher concentration and no micelles at the lower concentration. Apparent solubility of ABT-102 was 20-fold higher in concentrated than in diluted dispersions, because of micelles. In contrast, Caco-2 permeation of ABT-102 was independent of the ASD concentration, but three times faster than that of crystalline suspensions. Molecular solubility of ABT-102 (equilibrium dialysis) was also independent of the ASD concentration, but by a factor 2 higher than crystalline ABT-102. The total amount of ABT-102 accumulated in the acceptor during Caco-2 experiments exceeded the initial amount of molecularly dissolved drug in the donor. This may indicate that dissolution of amorphous microparticles present in aqueous dispersions induces lasting supersaturation maintaining enhanced permeation. The hypothesis is supported by a slower drug permeation when the microparticles were removed.

  9. Effect of the cation and the anion of an electrolyte on the solubility of DL-aminobutyric acid in aqueous solutions: measurement and modelling.

    Science.gov (United States)

    Soto, A; Arce, A; K Khoshkbarchi, M; Vera, J H

    1998-07-13

    The solubilities at 298.2 K of dl-aminobutyric acid in aqueous solutions of NaCl, KCl, NaNO(3) and KNO(3) were measured. The solubility of DL-aminobutyric acid was found to be influenced by the concentration and by the nature of both the cation and the anion of the electrolyte. Comparison of the results obtained in this study and those for other amino acids reported in the literature, indicates that the structure of the hydrocarbon backbone of an amino acid plays an important role in the interactions of an amino acid with an electrolyte. A thermodynamic model has been used to correlate the solubilities of DL-aminobutyric acid in aqueous electrolyte solutions. The activity coefficients of the amino acid in the electrolyte solutions, were represented by a model proposed by Khoshkbarchi and Vera [M.K. Khoshkbarchi, J.H. Vera, AIChE J. 42 (1996) 2354; M.K. Khoshkbarchi, J.H. Vera, Ind. Eng. Chem. Res. 35 (1996) 4755]. This model, which considers a combination of both long- and short-range interactions, contains only two adjustable parameters. All other parameters are available in the literature. The model can accurately correlate the solubility of dl-aminobutyric acid in aqueous solutions of electrolytes.

  10. Cesium cobaltdicarbollide-solubility, precipitation, and reactivity in basic aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, D.J.; Fanning, J.C.; Hugg, L.A.; Smith, W.A.; Terrell, A.S.; Yasinsac, L.; Todd, L.J.; Jasper, S.A. Jr.

    1994-12-31

    The title compound, Cs{sup +}[Co((3)-1,2-C{sub 2}B{sub 9}H{sub 11}){sub 2}]{sup {minus}}(CsCDC), was precipitated with a NaCDC solution from solutions containing CsCl. The reaction was followed by measuring loss of light intensity as the precipitate formed. The [Cs{sup +}] and [CDC{sup {minus}}] at the point of precipitation were estimated and approximate values of the K{sub sp} for CsCDC determined at room temperature: 8 {times} 10{sup {minus}6} (water), 7 {times} 10{sup {minus}6} (1 M NaOH), and 2 {times} 10{sup {minus}6} (5M NaCl/0.1 M KOH/1.0 M NaOH). In some cases, NaCDC precipitated from solution when added to the latter salt solution. For the medium, 5 M NaNO{sub 3}/0.1 M KOH/1.0 M NaOH a four-fold excess of NaCDC was added to a 10mM Cs{sup +} solution at 40{degrees}C and the [CDC{sup {minus}}] measured spectrophotometrically. Only CsCDC precipitated, and a K{sub sp} of 3.9 {times} 10{sup {minus}6} was determined. The solubilities of CsCDC were measured in NaNO{sub 3} and NaCl solutions at 30{sub C} as a function of the Na salt concentration. Reaction of the CDC{sup {minus}} with OH{sup {minus}} slowly produces B(OH{sub 4}{sup {minus}}, H{sub 2}, and CoO(OH). Reaction of 22 {mu}M CsCDC with 1M NaOH has a first order rate constant at 56{degrees}C of 8.8 {times} 10{sup {minus}7} s{sup {minus}1}, while that for 14 mM NaCDC is 7.2 {times} 10{sup {minus}7} s {sup {minus}1}. Activation energy for the reaction is 110 kJ.

  11. An experimental study of the solubility and speciation of tantalum in fluoride-bearing aqueous solutions at elevated temperature

    Science.gov (United States)

    Timofeev, A.; Migdisov, Art. A.; Williams-Jones, A. E.

    2017-01-01

    The solubility of Ta2O5 (solid) and the speciation of tantalum in HF-bearing aqueous solutions have been determined at temperatures of 100-250 °C and vapour-saturated water pressure. Tantalum is transported as the species Ta(OH)50 at low HF concentration and pH ∼1-3. At higher HF concentration, tantalum mobility is controlled by the species TaF3(OH)3- and TaF50; the presence of TaF50 is only evident at ⩽150 °C. Equilibrium constants range from -17.4 ± 0.45 to -16.4 ± 0.12 for the formation of Ta(OH)50 from crystalline Ta2O5 and from -8.24 ± 0.64 to -8.55 ± 0.68 for the formation of TaF3(OH)3- at 100 and 250 °C, respectively. For TaF50, they were determined to be 0.13 at 100 °C and -0.35 at 150 °C. In many respects, the behaviour of tantalum in acidic fluoride-bearing solutions is similar to that of niobium. The solubility of Ta2O5 (solid) is not dependent on HF concentration in fluoride-poor fluids, but rises rapidly at higher HF concentration. However, at the conditions of our experiments, namely a pH of ∼2, temperature up to 250 °C, and a wide range of HF concentrations, Ta2O5 (solid) solubility is almost invariably lower than that of Nb2O5 (solid). Modelling of Nb and Ta leaching confirmed the preferential mobility of niobium under most conditions expected in natural fluoride-rich hydrothermal systems. This modelling also demonstrated that both niobium and tantalum are rapidly deposited upon removal of fluoride from an acidic brine. As a result of hydrothermal alteration, the Nb/Ta ratios of secondary minerals may increase relative to those of the primary mineral, or remain largely unaffected, depending on the pH of the fluid.

  12. Deep architectures and deep learning in chemoinformatics: the prediction of aqueous solubility for drug-like molecules.

    Science.gov (United States)

    Lusci, Alessandro; Pollastri, Gianluca; Baldi, Pierre

    2013-07-22

    Shallow machine learning methods have been applied to chemoinformatics problems with some success. As more data becomes available and more complex problems are tackled, deep machine learning methods may also become useful. Here, we present a brief overview of deep learning methods and show in particular how recursive neural network approaches can be applied to the problem of predicting molecular properties. However, molecules are typically described by undirected cyclic graphs, while recursive approaches typically use directed acyclic graphs. Thus, we develop methods to address this discrepancy, essentially by considering an ensemble of recursive neural networks associated with all possible vertex-centered acyclic orientations of the molecular graph. One advantage of this approach is that it relies only minimally on the identification of suitable molecular descriptors because suitable representations are learned automatically from the data. Several variants of this approach are applied to the problem of predicting aqueous solubility and tested on four benchmark data sets. Experimental results show that the performance of the deep learning methods matches or exceeds the performance of other state-of-the-art methods according to several evaluation metrics and expose the fundamental limitations arising from training sets that are too small or too noisy. A Web-based predictor, AquaSol, is available online through the ChemDB portal ( cdb.ics.uci.edu ) together with additional material.

  13. Enhanced aqueous solubility of polycyclic aromatic hydrocarbons by green diester-linked cationic gemini surfactants and their binary solutions

    Science.gov (United States)

    Panda, Manorama; Fatma, Nazish; Kabir-ud-Din

    2016-07-01

    Three homologues of a novel biodegradable diester-linked cationic gemini surfactant series, CmH2m+1 (CH3)2N+(CH2COOCH2)2N+(CH3)2CmH2m+1.2Cl- (m-E2-m; m = 12, 14, 16), were used for investigation of the solubilization of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, anthracene and pyrene in single as well as binary surfactant solutions. Physicochemical parameters of the pure/mixed systems were derived by conductivity and surface tension measurements. Dissolution capacity of the equimolar binary surfactant solutions towards the PAHs was studied from the molar solubilization ratio (MSR), micelle-water partition coefficient (Km) and free energy of solubilization (ΔGs0) of the solubilizates. Influence of hydrophobic chain length of the dimeric surfactants on solubilization was characterized. Aqueous solubility of the PAHs was enhanced linearly with concentration of the surfactant in all the pure and mixed gemini-gemini surfactant systems.

  14. Improving aqueous solubility and antitumor effects by nanosized gambogic acid-mPEG₂₀₀₀ micelles.

    Science.gov (United States)

    Cai, Lulu; Qiu, Neng; Xiang, Mingli; Tong, Rongsheng; Yan, Junfeng; He, Lin; Shi, Jianyou; Chen, Tao; Wen, Jiaolin; Wang, Wenwen; Chen, Lijuan

    2014-01-01

    The clinical application of gambogic acid, a natural component with promising antitumor activity, is limited due to its extremely poor aqueous solubility, short half-life in blood, and severe systemic toxicity. To solve these problems, an amphiphilic polymer-drug conjugate was prepared by attachment of low molecular weight (ie, 2 kDa) methoxy poly(ethylene glycol) methyl ether (mPEG) to gambogic acid (GA-mPEG₂₀₀₀) through an ester linkage and characterized by (1)H nuclear magnetic resonance. The GA-mPEG₂₀₀₀ conjugates self-assembled to form nanosized micelles, with mean diameters of less than 50 nm, and a very narrow particle size distribution. The properties of the GA-mPEG₂₀₀₀ micelles, including morphology, stability, molecular modeling, and drug release profile, were evaluated. MTT (3-(4,5-dimethylthiazo l-2-yl)-2,5 diphenyl tetrazolium bromide) tests demonstrated that the GA-mPEG₂₀₀₀ micelle formulation had obvious cytotoxicity to tumor cells and human umbilical vein endothelial cells. Further, GA-mPEG₂₀₀₀ micelles were effective in inhibiting tumor growth and prolonged survival in subcutaneous B16-F10 and C26 tumor models. Our findings suggest that GA-mPEG₂₀₀₀ micelles may have promising applications in tumor therapy.

  15. Cloud droplet activation: solubility revisited

    Directory of Open Access Journals (Sweden)

    L. T. Padró

    2007-02-01

    Full Text Available Soluble compounds present in atmospheric aerosol facilitate their transformation into cloud droplets by depressing the equilibrium vapor pressure required for activation. Their impact depends on the amount of dissolved substance in the aerosol aqueous phase, which in turn is controlled by its solubility. This study explores the impact of particle curvature on solubility, expressed in terms of a Kelvin enhancement. The augmented solubility, termed "Curvature Enhanced Solubility" (CES, is then introduced into Köhler theory for assessment of its impact on CCN activity for several organic compounds with a wide range of aqueous solubility. The interfacial energy between solute and aqueous phase required for quantification of CES is determined from existing correlations based on bulk solubility, and concurrent measurements of contact angle and surface tension. A number of important findings arise from this study: i CES can substantially increase solubility and impact CCN activity but only if the aerosol is initially wet, ii CES can stabilize highly supersaturated solutions, and provide a mechanism for retention of an aerosol aqueous phase even at very low relative humidity (RH, and, iii trace amounts of surfactant impurities can magnify the impact of CES.

  16. A thermodynamic model for calculating methane solubility, density and gas phase composition of methane-bearing aqueous fluids from 273 to 523 K and from 1 to 2000 bar

    Science.gov (United States)

    Duan, Zhenhao; Mao, Shide

    2006-07-01

    A thermodynamic model is presented to calculate methane solubility, liquid phase density and gas phase composition of the H 2O-CH 4 and H 2O-CH 4-NaCl systems from 273 to 523 K (possibly up to 573 K), from 1 to 2000 bar and from 0 to 6 mol kg -1 of NaCl with experimental accuracy. By a more strict theoretical approach and using updated experimental data, this model made substantial improvements over previous models: (1) the accuracy of methane solubility in pure water in the temperature range between 273 and 283 K is increased from about 10% to about 5%, but confirms the accuracy of the Duan model [Duan Z., Moller N., Weare J.H., 1992a. Prediction of methane solubilities in natural waters to high ionic strength from 0 to 250 °C and from 0 to 1600 bar. Geochim. Cosmochim. Acta56, 1451-1460] above 283 K up to 2000 bar; (2) the accuracy of methane solubility in the NaCl aqueous solutions is increased from >12% to about 6% on average from 273 K and 1 bar to 523 K and 2000 bar; (3) this model is able to calculate water content in the gas phase and liquid phase density, which cannot be calculated by previous models; and (4) it covers a wider range of temperature and pressure space. With a simple approach, this model is extended to predict CH 4 solubility in other aqueous salt solutions containing Na +, K +, Mg 2+, Ca 2+, Cl - and SO42-, such as seawater and geothermal brines, with excellent accuracy. This model is also able to calculate homogenization pressure of fluid inclusions (CH 4-H 2O-NaCl) and CH 4 solubility in water at gas-liquid-hydrate phase equilibrium. A computer code is developed for this model and can be downloaded from the website: www.geochem-model.org/programs.htm.

  17. Solubility of toluene, benzene and TCE in high-microbial concentration systems.

    Science.gov (United States)

    Barton, John W; Vodraska, Chris D; Flanary, Sandie A; Davison, Brian H

    2008-12-01

    We report measurements of solubility limits for benzene, toluene, and TCE in systems that contain varying levels of biomass up to 0.13 g mL(-1) for TCE and 0.25 g mL(-1) for benzene and toluene. The solubility limit increased from 21 to 48 mM when biomass (in the form of yeast) was added to aqueous batch systems containing benzene. The toluene solubility limit increased from 4.9 to greater than 20mM. For TCE, the solubility increased from 8mM to more than 1000 mM. Solubility for TCE (trichloroethylene) was most heavily impacted by biomass levels, changing by two orders of magnitude as the microbial concentrations approach those in biofilms.

  18. Aqueous Solubility of Piperazine and 2-Amino-2-methyl-1-propanol plus Their Mixtures Using an Improved Freezing-Point Depression Method

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Neerup, Randi; Waseem Arshad, Muhammad

    2011-01-01

    In this work the solid–liquid equilibrium (SLE) and freezing-point depression (FPD) in the electrolytic binary aqueous systems piperazine (PZ, CAS No. 110-85-0) and aqueous 2-amino-2-methyl-1-propanol (AMP, CAS No. 124-68-5) were measured. The FPD and solubility were also determined in the ternary...... AMP–PZ–H2O system. A method was developed by which solubility can be determined at higher temperatures using the FPD setup. A total of 86 data points are listed in the full concentration range from (−35 to 90) °C. The solid phases piperazine hexahydrate (PZ·6H2O), piperazine hemihydrate (PZ·1/2H2O...

  19. Prediction and application in QSPR of aqueous solubility of sulfur-containing aromatic esters using GA-based MLR with quantum descriptors.

    Science.gov (United States)

    Yin, Chunsheng; Liu, Xinhui; Guo, Weimin; Lin, Teng; Wang, Xiaodong; Wang, Liansheng

    2002-07-01

    Quantitative structure-property relationships (QSPR) were developed using a genetic algorithm (GA)-based variable-selection approach with quantum chemical descriptors derived from AM1-based calculations (MOPAC7.0). With the QSPR models, the aqueous solubility of 71 aromatic sulfur-containing carboxylates, including phenylthio, and phenylsulfonyl carboxylates were efficiently estimated and predicted. Using GA-based multivariate linear regression (MLR) with cross-validation procedure, the most important descriptors were selected from a pool of 28 quantum chemical semi-empirical descriptors, including steric and electronic types, to build QSPR models. The molecular descriptors included molecular surface (SA), charges on carboxyl group (Q(oc)), the magnitude of the difference between E(HOMO) of the solute and ELUMO of water, divided by 100 (E(B)), which were main factors affecting the aqueous solubility of the compounds of interest. The resulted coefficients R and R2 of 0.9571 and 0.9161 and the prediction residual error sum of squares (PRESS) of 13.1768, revealed that it was accurate and reliable for the model to predict the aqueous solubility of the investigated organic compounds. If two outliers were omitted from the dataset, the resulted coefficients R = 0.9619, R2 = 0.9253, and PRESS = 10.3875 were significantly improved. Compared with stepwise regression analysis, the results obtained in this work were better and more reasonable. The best QSPR model were obtained by GA-based MLR. Reasonable mechanisms for aqueous solubility of the sulfur-containing carboxylates were investigated and interpreted.

  20. Prediction of aqueous solubility of drug-like molecules using a novel algorithm for automatic adjustment of relative importance of descriptors implemented in counter-propagation artificial neural networks.

    Science.gov (United States)

    Erić, Slavica; Kalinić, Marko; Popović, Aleksandar; Zloh, Mire; Kuzmanovski, Igor

    2012-11-01

    In this work, we present a novel approach for the development of models for prediction of aqueous solubility, based on the implementation of an algorithm for the automatic adjustment of descriptor's relative importance (AARI) in counter-propagation artificial neural networks (CPANN). Using this approach, the interpretability of the models based on artificial neural networks, which are traditionally considered as "black box" models, was significantly improved. For the development of the model, a data set consisting of 374 diverse drug-like molecules, divided into training (n=280) and test (n=94) sets using self-organizing maps, was used. Heuristic method was applied in preselecting a small number of the most significant descriptors to serve as inputs for CPANN training. The performances of the final model based on 7 descriptors for prediction of solubility were satisfactory for both training (RMSEP(train)=0.668) and test set (RMSEP(test)=0.679). The model was found to be a highly interpretable in terms of solubility, as well as rationalizing structural features that could have an impact on the solubility of the compounds investigated. Therefore, the proposed approach can significantly enhance model usability by giving guidance for structural modifications of compounds with the aim of improving solubility in the early phase of drug discovery.

  1. Thermodynamics of association of water soluble fullerene derivatives [C ₆₀ (OH)n, n = 0, 2, 4, 8 and 12] in aqueous media

    Indian Academy of Sciences (India)

    SONANKI KESHRI; B L TEMBE

    2017-09-01

    The thermodynamics of association of fullerene [C₆₀] and water-soluble fullerene derivatives, i.e., fullerols [C ₆₀ (OH)n, n = 0, 2, 4, 8 and 12] in aqueous solutions have been studied using molecular dynamics simulations. The potentials of mean force (PMFs) bring out the tendency of aggregation of these nanostructuresin water. The extent of hydroxylation seems to have a minor effect on the depth of the contact minima (the first minimum in the PMFs). The positions of the subsequent minima and maxima in the PMFs change with the size of the solute molecules. Higher stability of the contact state of highly hydroxylated fullerols is due to the van der Waals interactions whereas intermolecular solute-solvent hydrogen bonding nearly flattens the PMFs beyond the 2nd minima for higher fullerols. The solvent contributions to the PMFs for all the solute particles studied here are positive. Entropic and enthalpic contributions to the association of solute molecules are calculated in the isothermal-isobaric (NPT) ensemble. We find that the contact pair formation is governed by entropy with the enthalpic contributions being highly unfavorable, whereas the solvent assisted and solvent separated configurations show entropy-enthalpy compensation.

  2. Isolation of methylene dianiline and aqueous-soluble biodegradation products from polycarbonate-polyurethanes.

    Science.gov (United States)

    Tang, Y W; Labow, R S; Santerre, J P

    2003-08-01

    Polycarbonate-polyurethanes (PCNUs) have provided the medical device industry with practical alternatives to oxidation-sensitive polyether-urethanes (PEUs). To date, many studies have focused on PCNUs synthesized with 4,4'-methylene diphenyl-diisocyanate (MDI). The relative hydrolytic stability of this class of polyurethanes is actually quite surprising given the inherent hydrolytic potential of the aliphatic carbonate group. Yet, there has been little information reporting on the rationale for the material's demonstrated hydrolytic stability. Recent work has shown that PCNU materials have a strong sensitivity towards hydrolysis when changes are made to their hard segment content and/or chemistry. However, knowledge is specifically lacking in regards of the identification of cleavage sites and the specific nature of the biodegradation products. Using high-performance liquid chromatography, radiolabel tracers and mass spectrometry, the current study provides insight into the distribution of biodegradation products from the enzyme-catalyzed hydrolysis of five different PCNUs. The hydrolytic sensitivity of the materials is shown to be related to the distribution of products, which itself is a direct consequence of unique micro-structures formed within the different materials. While an MDI-based polymer was shown to be the most hydrolytically stable material, it was the only PCNU that produced its diamine analog, in this case 4,4'-methylene dianiline (MDA), as a degradation product. Given the concern over aromatic diamine toxicity, this finding is important and highlights the fact that relative biostability is a distinct issue from that of degradation product toxicity, and that both must be considered separately when assessing the impact of biodegradation on biomaterial in vivo compatibility.

  3. Non-monotonic course of protein solubility in aqueous polymer-salt solutions can be modeled using the sol-mxDLVO model.

    Science.gov (United States)

    Herhut, Marcel; Brandenbusch, Christoph; Sadowski, Gabriele

    2016-02-01

    Protein purification is often performed using cost-intensive chromatographic steps. To discover economic alternatives (e.g., crystallization), knowledge on protein solubility as a function of temperature, pH, and additives in solution as well as their concentration is required. State-of-the-art models for predicting protein solubility almost exclusively consider aqueous salt systems, whereas "salting-in" and "salting-out" effects induced by the presence of an additional polymer are not considered. Thus, we developed the sol-mxDLVO model. Using this newly developed model, protein solubility in the presence of one salt and one polymer, especially the non-monotonic course of protein solubility, could be predicted. Systems considered included salts (NaCl, Na-p-Ts, (NH(4))(2) SO(4)) and the polymer polyethylene glycol (MW: 2000 g/mol, 12000 g/mol) and proteins lysozyme from chicken egg white (pH 4 to 5.5) and D-xylose ketol-isomerase (pH 7) at 298.15 K. The results show that by using the sol-mxDLVO model, protein solubility in polymer-salt solutions can be modeled in good agreement with the experimental data for both proteins considered. The sol-mxDLVO model can describe the non-monotonic course of protein solubility as a function of polymer concentration and salt concentration, previously not covered by state-of-the-art models.

  4. Aqueous Geochemistry at High Pressures and High Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Bass, Jay D. [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2015-05-21

    This project is aimed at experimental characterization of the sound velocities, equations of state (EOS), and derived physical and chemical properties of aqueous solutions and carbon dioxide at extreme pressure and temperature conditions relevant to processes occurring in the interior of the Earth. Chemical transport, phase changes (including melting), fluid-solid reactions, and formation of magmatic liquids at convergent plat boundaries are a key motivation for this project. Research in this area has long been limited by the extreme experimental challenges and lack of data under the appropriate pressure-temperature (P-T) conditions. The vast majority of studies of aqueous geochemistry relevant to terrestrial problems of fluid-rock interactions have been conducted at 0.3 GPa or less, and the widely used Helgeson-Kirkham-Flowers equation of state for aqueous species is applicable only at ~ < 0.5 GPa. These limits are unfortunate because fluid flow and reactions plays a central role in many deeper environments. Recent efforts including our own, have resulted in new experimental techniques that now make it possible to investigate properties of homogeneous and heterogeneous equilibria involving aqueous species and minerals over a much broader range of pressure and temperature appropriate for deep crustal and upper mantle processes involving water-rich fluids. We carried out 1) Brillouin scattering measurements of the equations of state and molar volume of water and carbon dioxide to over 10 GPa and 870K using precise resistance heating of samples under pressure in the diamond anvil cell, and 2) the phase diagrams of the water and CO2, and 3) Exploring new experimental approaches, including CO2 laser heating of samples in a diamond cell, to measurements of sound velocities, EOS, and phase relations by Brillouin scattering to far greater pressures and temperatures.

  5. High mobility epitaxial graphene devices via aqueous-ozone processing

    Science.gov (United States)

    Yager, Tom; Webb, Matthew J.; Grennberg, Helena; Yakimova, Rositsa; Lara-Avila, Samuel; Kubatkin, Sergey

    2015-02-01

    We find that monolayer epitaxial graphene devices exposed to aggressive aqueous-ozone processing and annealing became cleaner from post-fabrication organic resist residuals and, significantly, maintain their high carrier mobility. Additionally, we observe a decrease in carrier density from inherent strong n-type doping to extremely low p-type doping after processing. This transition is explained to be a consequence of the cleaning effect of aqueous-ozone processing and annealing, since the observed removal of resist residuals from SiC/G enables the exposure of the bare graphene to dopants present in ambient conditions. The resulting combination of charge neutrality, high mobility, large area clean surfaces, and susceptibility to environmental species suggest this processed graphene system as an ideal candidate for gas sensing applications.

  6. Variability of SO2 in an intensive fog in North China Plain: Evidence of high solubility of SO2

    Institute of Scientific and Technical Information of China (English)

    Qiang Zhang; Xuexi Tie; Weili Lin; Junji Cao; Jiannong Quan; Liang Ran; Wanyun Xu

    2013-01-01

    A field experiment was conducted in an intensive fog event between November 5 and November 8,2009,in a heavily SO2-polluted area in North China Plain (NCP),to measure SO2 and other air pollutants,liquid water content (LWC) of fog droplets,and other basic meteorological parameters.During the fog period,the concentrations of SO2 showed large variability,which was closely related to the LWC in the fogdroplets.The averaged concentration of SO2 during non-fog periods was about 25 ppbv,while during the fog period,it rapidly reduced to about 4-7 ppbv.Such large reduction of SO2 suggested that a majority of SO2 (about 70%-80%) had reverted from gas to aqueous phase on account of the high solubility of SO2 in water in the fog droplets.However,the calculated gas to aqueous phase conversion was largely underestimated by merely using the Henry's Law constant of SO2,thus suggesting that aqueous reaction of SO2 in fog droplets might play some important role in enhancing the solubility of SO2.To simplify the phenomenon,an "effective solubility coefficient" is proposed in this study.This variability of SO2 measurement during the extensive fog event provides direct evidence of oxidation of SO2 in fog droplets,thus providing important implications for better understanding of the acidity in clouds,precipitation,and fogs in NCP,now a central environmental focus in China due to its rapid economic development.

  7. The Solubility of 242PuO2 in the Presence of Aqueous Fe(II): The Impact of Precipitate Preparation

    Energy Technology Data Exchange (ETDEWEB)

    Felmy, Andrew R.; Moore, Dean A.; Buck, Edgar C.; Conradson, Steven D.; Kukkadapu, Ravi K.; Sweet, Lucas E.; Abrecht, David G.; Ilton, Eugene S.

    2014-01-28

    The solubility of different forms of precipitated 242PuO2(am) were examined in solutions containing aqueous Fe(II) over a range of pH values. The first series of 242PuO2(am) suspensions were prepared from a 242Pu(IV) stock that had been treated with thenoyltrifluoroacetone (TTA) to remove the 241Am originating from the decay of 241Pu. These 242PuO2(am) suspensions showed much higher solubilities at the same pH value and Fe(II) concentration than previous studies using 239PuO2(am). X ray absorption fine structure (XAFS) spectroscopy of the precipitates showed a substantially reduced Pu-Pu backscatter over that previously observed in 242PuO2(am) precipitates, indicating that the 242PuO2(am) precipitates purified using TTA lacked the long range order previously found in 239PuO2(am) precipitates. The Pu(IV) stock solution was subsequently repurified using an ion exchange resin and an additional series of 242PuO2(am) precipitates prepared. These suspensions showed higher redox potentials and total aqueous Pu concentrations than the TTA purified stock solution. The higher redox potential and aqueous Pu concentrations were in general agreement with previous studies on 242PuO2(am) precipitates, presumably due to the removal of possible organic compounds originally present in the TTA purified stock. 242PuO2(am) suspensions prepared with both stock solutions showed almost identical solubilities in Fe(II) containing solutions even though the initial aqueous Pu concentrations before the addition of Fe(II) were orders of magnitude different. By examining the solubility of 242PuO2(am) prepared from both stocks in this way we have essentially approached equilibrium from both the undersaturated and oversaturated

  8. The solubility of {sup 242}PuO{sub 2} in the presence of aqueous Fe(II). The impact of precipitate preparation

    Energy Technology Data Exchange (ETDEWEB)

    Felmy, Andrew R.; Moore, Dean A.; Buck, Edgar; Kukkadapu, Ravi; Sweet, Lucas; Abrecht, David; Ilton, Eugene S. [Pacific Northwest National Laboratory, Richland, WA (United States); Conrados, Steven D. [Los Alamos National Laboratory, Los Alamos, NM (United States)

    2014-07-01

    The solubility of different forms of precipitated {sup 242}PuO{sub 2}(am) were examined in solutions containing aqueous Fe(II) over a range of pH values. The first series of {sup 242}PuO{sub 2}(am) suspensions were prepared from a {sup 242}Pu(IV) stock that had been treated with thenoyltrifluoroacetone (TTA) to remove the {sup 241}Am originating from the decay of {sup 241}Pu. These {sup 242}PuO{sub 2}(am) suspensions showed much higher solubilities at the same pH value and Fe(II) concentration than previous studies using {sup 239}PuO{sub 2}(am). X-ray absorption fine structure (XAFS) spectroscopy of the precipitates showed a substantially reduced Pu-Pu backscatter over that previously observed in {sup 239}PuO{sub 2}(am) precipitates, indicating that the {sup 242}PuO{sub 2}(am) precipitates purified using TTA lacked the long range order previously found in{sup 239}PuO{sub 2}(am) precipitates. The Pu(IV) stock solution was subsequently re-purified using an ion exchange resin and an additional series of {sup 242}PuO{sub 2}(am) precipitates prepared. These suspensions showed higher redox potentials and total aqueous Pu concentrations than the TTA purified stock solution. The higher redox potential and aqueous Pu concentrations were in general agreement with previous studies on {sup 242}PuO{sub 2}(am) precipitates, presumably due to the removal of possible organic compounds originally present in the TTA purified stock. {sup 242}PuO{sub 2}(am) suspensions prepared with both stock solutions showed almost identical solubilities in Fe(II) containing solutions even though the initial aqueous Pu concentrations before the addition of Fe(II) were orders of magnitude different. By examining the solubility of {sup 242}PuO{sub 2}(am) prepared from both stocks in this way we have essentially approached equilibrium from both the undersaturated and oversaturated conditions. The final aqueous Pu concentrations are predictable using a chemical equilibrium model which includes the

  9. Observation of Aqueous Cm(III)/Eu(III) and UO22+ Nanoparticulates at Concentrations Approaching Solubility Limit by Laser-Induced Fluorescence Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zheming; Felmy, Andrew R.; Xia, Yuanxian; Buck, Edgar C.

    2006-07-20

    Eu(III), Cm(III) and the uranyl ion display intense fluorescence spectra in the visible range and the spectroscopic characteristics are dependent on the composition and structure of the individual metal complexes. In this work, we demonstrate the application of laser-induced time-resolved fluorescence spectroscopy in identification of nanoparticles of (1) Eu(III) and Cm(III) in basic solutions (pH > 10) in the presence of organic chelates including EDTA, HEDTA, NTA and oxalate and (2) sodium uranyl phosphate after equilibration with synthetic sodium uranyl phosphate suspensions. Fluorescence spectral and SEM results indicate that Eu(III) and Cm(III) can exist as colloidal nanoparticles in filtered 0.1 M NaOH solutions. Such nanoparticles, which display largely red-shifted fluorescence spectra as compared with the aqueous complexes and unusually short fluorescence lifetimes, contribute to the measured concentrations of Eu(III)/Cm(III) in the aqueous solutions. Similarly, uranyl spectroscopic signatures indicate that the determination of the solubility of uranium phosphate minerals is prone to the presence of uranyl phosphate nanoparticles. Due to the presence of such nanoparticles, the common solubility measurements may only indicate an upper limit of the ''true'' solubility.

  10. Observation of aqueous Cm(III)/Eu(III) and UO{sub 2} {sup 2+} nanoparticulates at concentrations approaching solubility limit by laser-induced fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zheming [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)]. E-mail: Zheming.wang@pnl.gov; Felmy, Andrew R. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Xia Yuanxian [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Buck, Edgar C. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2006-07-20

    Eu(III), Cm(III) and the uranyl ion display intense fluorescence spectra in the visible range and the spectroscopic characteristics are dependent on the composition and structure of the individual metal complexes. In this work, we demonstrate the application of laser-induced time-resolved fluorescence spectroscopy in identification of nanoparticles of (i) Eu(III) and Cm(III) in basic solutions (pH > 10) in the presence of organic chelates including EDTA, HEDTA, NTA and oxalate and (ii) sodium uranyl phosphate after equilibration with synthetic sodium uranyl phosphate suspensions. Fluorescence spectral and SEM results indicate that Eu(III) and Cm(III) can exist as colloidal nanoparticles in filtered 0.1 M NaOH solutions. Such nanoparticles, which display largely red-shifted fluorescence spectra as compared with the aqueous complexes and unusually short fluorescence lifetimes, contribute to the measured concentrations of Eu(III)/Cm(III) in the aqueous solutions. Similarly, uranyl spectroscopic signatures indicate that the determination of the solubility of uranium phosphate minerals is prone to the presence of uranyl phosphate nanoparticles. Due to the presence of such nanoparticles, the common solubility measurements may only indicate an upper limit of the 'true' solubility.

  11. Green synthesis of highly concentrated aqueous colloidal solutions of large starch-stabilised silver nanoplatelets.

    Science.gov (United States)

    Cheng, Fei; Betts, Jonathan W; Kelly, Stephen M; Hector, Andrew L

    2015-01-01

    A simple, environmentally friendly and cost-effective method has been developed to prepare a range of aqueous silver colloidal solutions, using ascorbic acid as a reducing agent, water-soluble starch as a combined crystallising, stabilising and solubilising agent, and water as the solvent. The diameter of silver nanoplatelets increases with higher concentrations of AgNO3 and starch. The silver nanoparticles are also more uniform in shape the greater the diameter of the nanoparticles. Colloidal solutions with a very high concentration of large, flat, hexagonal silver nanoplatelets (~230 nm in breadth) have been used to deposit and fix an antibacterial coating of these large starch-stabilised silver nanoplates on commercial cotton fibres, using a simple dip-coating process using water as the solvent, in order to study the dependence of the antibacterial properties of these nanoplatelets on their size.

  12. Bupivacaine salts of diflunisal and other aromatic hydroxycarboxylic acids: aqueous solubility and release characteristics from solutions and suspensions using a rotating dialysis cell model.

    Science.gov (United States)

    Østergaard, Jesper; Larsen, Susan W; Parshad, Henrik; Larsen, Claus

    2005-11-01

    In the search for poorly soluble bupivacaine salts potentially enabling prolonged postoperative pain relief after local joint administration in the form of suspensions the solubility of bupivacaine salts of diflunisal and other aromatic hydroxycarboxylic acids were investigated together with the release characteristics of selected 1:1 salts from solutions and suspensions using a rotating dialysis cell model. The poorest soluble bupivacaine salts were obtained from the aromatic ortho-hydroxycarboxylic acids diflunisal, 5-iodosalicylic acid, and salicylic acid (aqueous solubilities: 0.6-1.9 mM at 37 degrees C). Diffusant appearance rates in the acceptor phase upon instillation of solutions of various salts in the donor cell applied to first-order kinetics. Calculated permeability coefficients for bupivacaine and the counterions diflunisal, 5-iodosalicylic acid, and mandelic acid were found to be correlated with the molecular size of the diffusants. Release experiments at physiological pH involving suspensions of the bupivacaine-diflunisal salt revealed that at each sampling point the diflunisal concentration exceeded that of bupivacaine in the acceptor phase. However, after an initial lag period, a steady state situation was attained resulting in equal and constant fluxes of the two diffusants controlled by the permeability coefficients in combination with the solubility product of the salt. Due to the fact that the saturation solubility of the bupivacaine-salicylic acid salt in water exceeded that of bupivacaine at pH 7.4, suspensions of the latter salt were unable to provide simultaneous release of the cationic and anionic species at pH 7.4. The release profiles were characterised by a rapid release of salicylate accompanied by a much slower appearance of bupivacaine in the acceptor phase caused by precipitation of bupivacaine base from the solution upon dissolution of the salt in the donor cell.

  13. Modeling of CO2 Solubility in Aqueous Potassium Lysinate Solutions at Post-Combustion CO2 Capture Conditions

    Science.gov (United States)

    Bian, Y.; Shen, S.

    2017-05-01

    Aqueous potassium lysinate (LysK) has been proposed as an alternative to aqueous alkanolamines for CO2 capture due to fast kinetics and large absorption capacity. However, thermodynamic modeling for aqueous LysK system has not been available yet. In this work, a modified Kent-Eisenberg model with correlated equilibrium constants was developed to interpret the vapor-liquid equilibrium (VLE) data at postcombustion capture conditions. The predictions from the developed model are in good agreement with the experimental results with AAD within 19 %.

  14. Thermodynamic modeling of acidic gas solubility in aqueous solutions of MEA, MDEA and MEA-MDEA blends

    DEFF Research Database (Denmark)

    Vrachnos, Ath.; Kontogeorgis, Georgios; Voutsas, EC

    2006-01-01

    The thermodynamic framework that was developed in a previous work [Vrachnos et al. Ind. Eng. Chem. Res. 2004, 43, 2798] for the description of chemical and vapor-liquid equilibria of carbon dioxide, hydrogen sulfide, and their mixtures in aqueous methyldiethanolamine (MDEA) solutions is revised...... and extended in this study to the absorption of carbon dioxide into aqueous monoethanolamine (MEA) solutions and aqueous MDEA-MEA blends. The results of the model are compared with experimental data taken from the literature. Very satisfactory predictions of acidic gas vapor-liquid equilibrium over MDEA, MEA...

  15. Preparation of detergent-lipase complexes utilizing water-soluble amphiphiles in single aqueous phase and catalysis of transesterifications in homogeneous organic solvents.

    Science.gov (United States)

    Mine, Y; Fukunaga, K; Maruoka, N; Nakao, K; Sugimura, Y

    2000-01-01

    A novel method of preparing detergent-enzyme complexes that can be employed in organic media was developed utilizing newly synthesized water-soluble nonionic gemini-type detergents, N,N-bis(3-D-gluconamidopropyl)-3-(dialkyl-L-glutamatecarbonyl)propanamides (BIG2CnCA: n = 10,12,14,16,18) and N,N-bis(3-D-lactonamidopropyl)-3-(dialkyl-L-glutamatecarbonyl)propanamides (BIL2CnCA: n = 16,18), and nonionic twin-headed detergents, N,N-bis(3-D-gluconamidopropyl)alkanamides (BIG1Cn: n = 12,14,16,18,delta9). This method simply entails mixing a selected enzyme with an appropriate detergent in an aqueous solution followed by lyophilization, and it offers the advantages of enhanced enzymatic activity in organic solvents and eliminates both enzyme loss and the necessity for an organic solvent in the preparation stage. Using various modified lipases originating from Aspergillus niger (Lipase A), Candida rugosa (Lipase C), Pseudomonas cepacia (Lipase P), and porcine pancreas (PPL), prepared using the novel method and detergents, including conventional synthesized nonionic detergents such as dialkyl N-D-glucona-L-glutamates (2CnGE: n = 12,18delta9) and octanoyl-N-methylglucamide (MEGA-8), enantioselective transesterifications of 6-methyl-5-hepten-2-ol (sulcatol) and 2,2-dimethyl-1,3-dioxolane-4-methanol (solketal) with a vinyl or isopropenyl carboxylate were carried out in an organic solvent. The modified lipase activity was influenced by both the lipases and the structure of the detergents. The value for the hydrophile-lipophile balance (HLB) of the detergent provided a means of correlating the structure and the obtained modified lipase activity. For detergents of the same class with a HLB value of approximately 9 and 12, the highest activity was obtained for Lipase A and Lipase P, and Lipase C and PPL, respectively. Among detergents of the same HLB value tested, the gemini-type detergents possessing the most bulky head and tail were most effective as a modifier for lipases of all

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

    Science.gov (United States)

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

    2015-07-06

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

  17. Use of the theory of Lifshitz-Slyosov-Wagner for the evaluation of the aqueous solubility of dodecane

    CERN Document Server

    Espinoza, Loredana; Rivas, Issarly; Urbina-Villalba, German

    2016-01-01

    The solubility of dodecane was determined using the theory of Lifshitz-Slyosov-Wagner for the Ostwald ripening phenomenon. For this purpose, a set of dodecane in water nanoemulsions stabilized with sodium dodecylsulfate was prepared. The average cubic radius of the dispersions was followed as a function of time for volume fractions between 0.001 and 0.00001. The correct solubility (5.5 x 10-9 m3/m3) was only reproduced by the most dilute system.

  18. Photodecomposition of hydrogen peroxide in highly saline aqueous medium

    Directory of Open Access Journals (Sweden)

    A. J. Luna

    2006-09-01

    Full Text Available The photodecomposition of hydrogen peroxide was performed in highly saline aqueous medium (60 g.L-1 of NaCl. The Fe3+/H2O2/NaCl/UV system was tested at temperatures from 20 to 50 ºC, while the intervals of concentration of Fe3+ and H2O2 were 1 to 2.5 mM and 230 to 630 mM, respectively. It is known from the literature that chloride is an inhibitor of the oxidation of organic compound in aqueous medium, but this effect has not been observed to be expressive for hydrogen peroxide. Despite this result, experiments were conducted in presence of high concentration of salt (60 g.L-1, emulating the agrochemical process condition. The series of measurements has been evaluated and correlated. Thermal and photochemical dependencies were described satisfactorily by a simplified kinetic model. The apparent activation energy was estimated to be 27.6 kJ.mol-1.

  19. Antimony(III) complexing with O-bearing organic ligands in aqueous solution: An X-ray absorption fine structure spectroscopy and solubility study

    Science.gov (United States)

    Tella, Marie; Pokrovski, Gleb S.

    2009-01-01

    The stability and structure of aqueous complexes formed by trivalent antimony (Sb III) with carboxylic acids (acetic, adipic, malonic, lactic, oxalic, tartaric, and citric acid), phenols (catechol), and amino acids (glycine) having O- and N-functional groups (carboxyl, alcoholic hydroxyl, phenolic hydroxyl and amine) typical of natural organic matter, were determined at 20 and 60 °C from solubility and X-ray absorption fine structure (XAFS) spectroscopy measurements. In organic-free aqueous solutions and in the presence of acetic, adipic, malonic acids and glycine, both spectroscopic and solubility data are consistent with the dominant formation of Sb III hydroxide species, Sb(OH)3-nn+,Sb(OH)30andSb(OH)4-, at strongly acid, acid-to-neutral and basic pH, respectively, demonstrating negligible complexing with mono-functional organic ligands (acetic) or those having non adjacent carboxylic groups (adipic, malonic). In contrast, in the presence of poly-functional carboxylic and hydroxy-carboxylic acids and catechol, Sb III forms stable 1:1 and 1:2 complexes with the studied organic ligands over a wide pH range typical of natural waters (3 cycle. Stability constants for these species, generated from Sb 2O 3 (rhomb.) solubility experiments, were used to model Sb complexing with natural humic acids possessing the same functional groups as those investigated in this study. Our predictions show that in an aqueous solution of pH between 2 and 10, containing 1 μg/L of Sb and 5 mg/L of dissolved organic carbon (DOC), up to 35% of total dissolved Sb binds to aqueous organic matter via carboxylic and hydroxy-carboxylic groups. This amount of complexed Sb for typical natural DOC concentrations is in agreement with that estimated from dialysis experiments performed with commercial humic acid in our work and those available in the literature for a range of standardized IHSS humic acids. Our results imply that a significant part of Sb is likely to be bound with humic acids via

  20. High-Resolution Electrospray Ionization Mass Spectrometry Analysis of Water- Soluble Organic Aerosols Collected with a Particle into Liquid Sampler

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, Adam P.; Nizkorodov, Serguei; Laskin, Julia; Laskin, Alexander

    2010-10-01

    This work demonstrates the utility of a particle-into-liquid sampler (PILS) a technique traditionally used for identification of inorganic ions present in ambient or laboratory aerosols for the analysis of water soluble organic aerosol (OA) using high resolution electrospray ionization mass spectrometry (HR ESI-MS). Secondary organic aerosol (SOA) was produced from 0.5 ppm mixing ratios of limonene and ozone in a 5 m3 Teflon chamber. SOA was collected simultaneously using a traditional filter sampler and a PILS. The filter samples were later extracted with either water or acetonitrile, while the aqueous PILS samples were analyzed directly. In terms of peak intensities, types of detectable compounds, average O:C ratios, and organic mass to organic carbon ratios, the resulting high resolution mass spectra were essentially identical for the PILS and filter based samples. SOA compounds extracted from both filter/acetonitrile extraction and PILS/water extraction accounted for >95% of the total ion current in ESI mass spectra. This similarity was attributed to high solubility of limonene SOA in water. In contrast, significant differences in detected ions and peak abundances were observed for pine needle biomass burning organic aerosol (BBOA) collected with PILS and filter sampling. The water soluble fraction of BBOA is considerably smaller than for SOA, and a number of unique peaks were detectable only by the filter/acetonitrile method. The combination of PILS collection with HR-ESI-MS analysis offers a new approach for molecular analysis of the water-soluble organic fraction in biogenic SOA, aged photochemical smog, and BBOA.

  1. Modified water solubility of milk protein concentrate powders through the application of static high pressure treatment.

    Science.gov (United States)

    Udabage, Punsandani; Puvanenthiran, Amirtha; Yoo, Jin Ah; Versteeg, Cornelis; Augustin, Mary Ann

    2012-02-01

    The effects of high pressure (HP) treatment (100-400 MPa at 10-60 °C) on the solubility of milk protein concentrate (MPC) powders were tested. The solubility, measured at 20 °C, of fresh MPC powders made with no HP treatment was 66%. It decreased by 10% when stored for 6 weeks at ambient temperature (~20 °C) and continued to decrease to less than 50% of its initial solubility after 12 months of storage. Of the combinations of pressure and heat used, a pressure of 200 MPa at 40 °C applied to the concentrate before spray drying was found to be the most beneficial for improved solubility of MPC powders. This combination of pressure/heat improved the initial cold water solubility to 85%. The solubility was maintained at this level after 6 weeks storage at ambient temperature and 85% of the initial solubility was preserved after 12 months. The improved solubility of MPC powders on manufacture and on storage are attributed to an altered surface composition arising from an increased concentration of non-micellar casein in the milk due to HP treatment prior to drying. The improved solubility of high protein powders (95% protein) made from blends of sodium caseinate and whey protein isolate compared with MPC powders (~85% protein) made from ultrafiltered/diafiltered milk confirmed the detrimental role of micellar casein on solubility. The results suggest that increasing the non-micellar casein content by HP treatment of milk or use of blends of sodium caseinate and whey proteins are strategies that may be used to obtain high protein milk powders with enhanced solubility.

  2. HIGH PRESSURE PHASE EQUILIBRIUM: PREDICTION OF ESSENTIAL OIL SOLUBILITY

    Directory of Open Access Journals (Sweden)

    Lúcio CARDOZO-FILHO

    1997-12-01

    Full Text Available This work describes a method to predict the solubility of essential oils in supercritical carbon dioxide. The method is based on the formulation proposed in 1979 by Asselineau, Bogdanic and Vidal. The Peng-Robinson and Soave-Redlich-Kwong cubic equations of state were used with the van der Waals mixing rules with two interaction parameters. Method validation was accomplished calculating orange essential oil solubility in pressurized carbon dioxide. The solubility of orange essential oil in carbon dioxide calculated at 308.15 K for pressures of 50 to 70 bar varied from 1.7± 0.1 to 3.6± 0.1 mg/g. For same the range of conditions, experimental solubility varied from 1.7± 0.1 to 3.6± 0.1 mg/g. Predicted values were not very sensitive to initial oil composition.Este trabalho descreve uma metodologia para o cálculo da solubilidade de óleos essenciais em dióxido de carbono a altas pressões baseada na formulação proposta em 1979 por Asselineau, Bogdanic e Vidal. Foram utilizadas as equações cúbicas de estado de Peng-Robinson e Soave-Redlich-Kwong com regras de mistura de van der Waals com dois parâmetros de interação. O cálculo da solubilidade do óleo essencial de laranja em dióxido de carbono pressurizado foi usado para validação do método. A solubilidade calculada a 308,15 K para pressões entre 50 e 70 bar variou entre 1,5 e 4,1 mg/g. Valores experimentais para as mesmas condições variam entre 1,7± 0.1 a 3,6± 0.1 mg/g. Os valores preditos não são muito sensíveis à composição inicial do óleo essencial.

  3. Cell Model of In-cloud Scavenging of Highly Soluble Gases

    CERN Document Server

    Baklanov, Alexander; Fominykh, Andrew; Krasovitov, Boris

    2012-01-01

    We investigate mass transfer during absorption of highly soluble gases such as HNO_{3}, H_{2}O_{2} by stagnant cloud droplets in the presence of inert admixtures. Thermophysical properties of the gases and liquids are assumed to be constant. Diffusion interactions between droplets, caused by the overlap of depleted of soluble gas regions around the neighboring droplets, are taken into account in the approximation of a cellular model of a gas-droplet suspension whereby a suspension is viewed as a periodic structure consisting of the identical spherical cells with periodic boundary conditions at the cell boundary. Using this model we determined temporal and spatial dependencies of the concentration of the soluble trace gas in a gaseous phase and in a droplet and calculated the dependence of the scavenging coefficient on time. It is shown that scavenging of highly soluble gases by cloud droplets leads to essential decrease of soluble trace gas concentration in the interstitial air. We found that scavenging coeff...

  4. Modeling of glycine solubility in aqueous HCl-MgCl2 system and its application in phase transition of glycine by changing media and supersaturation

    Science.gov (United States)

    Ansari, Ziaul Haque; Zeng, Yan; Zhang, Yan; Demopoulos, George P.; Li, Zhibao

    2017-06-01

    The solubility of glycine in HCl and HCl-MgCl2 solutions was measured from 283.15 to 343.15 K and found to increase with temperature and increase linearly with the concentration of HCl. The MSE model integrated in the OLI platform was modified by regressing the experimental and literature solubility data through the adjustment of the middle-range interaction parameters. After parameterization, the model can accurately calculate the solubility with the average absolute deviation lower than 3.5% and thus be able to predict supersaturation of glycine. Crystallization of different polymorphs of glycine in water, HCl, NaOH, MgCl2, and HCl-MgCl2 aqueous solutions was performed. The effects of medium, temperature, supersaturation, and time on the crystallization were investigated. It was found that only in the HCl solution the formation of single α-glycine phase was achieved under all the investigated temperature and holding time. α-glycine or its mixture with γ-glycine or C4H18N2O4·HCl was produced in systems other than HCl solution depending on the conditions.

  5. Deep cavitand receptors with pH-independent water solubility.

    Science.gov (United States)

    Lledó, Agustí; Rebek, Julius

    2010-12-07

    Pendant oligoethyleneglycol groups confer water solubility to a cavitand over a wide pH range. The kinetic stability of the host-guest complexes reveals an effective stabilization through hydrogen bonding even in the highly competitive aqueous environment.

  6. Photoyellowing inhibition of bleached high yield pulps using novel water-soluble UV screens.

    Science.gov (United States)

    Argyropoulos, D S; Halevy, P; Peng, P

    2000-02-01

    To address the deficiencies of benzophenone UV screens for preventing brightness reversion in high yield mechanical papers, we synthesized a new series of such materials with enhanced water solubility and compatibility with the lignocellulosic substrate. A series of 2,4-dihydroxybenzophenones (DHB) were synthesized containing various Mannich bases at the C3 position of one of its rings. They possess the UV-screening ability of o-hydroxylbenzophenones, and they also contain tertiary nitrogen atoms that may function as radical scavengers. Aqueous solutions of the hydrochloride salt of 3-(dimethylaminomethylene)-2,4-dihydroxylbenzophenone (1), when applied on bleached chemithermomechanical pulp (CTMP) sheets, were significantly more efficient in preventing photoyellowing than the original DHB applied on the sheets from ethanol-water solutions. This confirmed our original hypothesis that increasing the compatibility of the UV screen with the lignocellulosic matrix would increase its efficiency in preventing photoyellowing. Compound 1, however, was found to be somewhat more effective than its hydrochloride salt toward preventing photoyellowing. This was attributed to the synergistic action of the free tertiary aminic center attached on the molecule with its UV-screening ability. To comprehend further the various parameters that influence the photoyellowing inhibition performance of these compounds and DHB with bleached CTMP pulp fibers, a series of handsheets were prepared at different pH. The interactions of the protonated compound 1 with pulp fibers were then evaluated by studying their kinetics of absorption and desorption to and from the fiber matrix. This part of our study found that the adsorption of protonated Mannich derivatives of DHB onto pulp is most likely governed by a cation-exchange mechanism involving the cationic amine group with the sulfonic and carboxylic acid groups located on the surface of the fibers. The pH the paper sheet was made from was also

  7. Chemical analysis of simulated high level waste glasses to support stage III sulfate solubility modeling

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-17

    The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms within the DOE complex. These wastes can contain relatively high concentrations of sulfate, which has low solubility in borosilicate glass. This is a significant issue for low-activity waste (LAW) glass and is projected to have a major impact on the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Sulfate solubility has also been a limiting factor for recent high level waste (HLW) sludge processed at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). The low solubility of sulfate in glass, along with melter and off-gas corrosion constraints, dictate that the waste be blended with lower sulfate concentration waste sources or washed to remove sulfate prior to vitrification. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerate mission completion.The objective of the current scope being pursued by SHU is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DWPF and WTP, allowing for enhanced waste loadings and waste throughput at these facilities. A series of targeted glass compositions was selected to resolve data gaps in the model and is identified as Stage III. SHU fabricated these glasses and sent samples to SRNL for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for the Stage III, simulated HLW glasses fabricated by SHU in support of the sulfate solubility model development.

  8. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery.

    Science.gov (United States)

    Li, Bin; Nie, Zimin; Vijayakumar, M; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

    2015-02-24

    Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25 Wh l(-1)). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167 Wh l(-1) is demonstrated with a near-neutral 5.0 M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from -20 to 50 °C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications.

  9. An Aqueous Redox-Flow Battery with High Capacity and Power: The TEMPTMA/MV System.

    Science.gov (United States)

    Janoschka, Tobias; Martin, Norbert; Hager, Martin D; Schubert, Ulrich S

    2016-11-07

    Redox-flow batteries (RFB) can easily store large amounts of electric energy and thereby mitigate the fluctuating output of renewable power plants. They are widely discussed as energy-storage solutions for wind and solar farms to improve the stability of the electrical grid. Most common RFB concepts are based on strongly acidic metal-salt solutions or poorly performing organics. Herein we present a battery which employs the highly soluble N,N,N-2,2,6,6-heptamethylpiperidinyl oxy-4-ammonium chloride (TEMPTMA) and the viologen derivative N,N'-dimethyl-4,4-bipyridinium dichloride (MV) in a simple and safe aqueous solution as redox-active materials. The resulting battery using these electrolyte solutions has capacities of 54 Ah L(-1) , giving a total energy density of 38 Wh L(-1) at a cell voltage of 1.4 V. With peak current densities of up to 200 mA cm(-2) the TEMPTMA/MV system is a suitable candidate for compact high-capacity and high-power applications.

  10. How to design a good photoresist solvent package using solubility parameters and high-throughput research

    Science.gov (United States)

    Tate, Michael P.; Cutler, Charlotte; Sakillaris, Mike; Kaufman, Michael; Estelle, Thomas; Mohler, Carol; Tucker, Chris; Thackeray, Jim

    2014-03-01

    Understanding fundamental properties of photoresists and how interactions between photoresist components affect performance targets are crucial to the continued success of photoresists. More specifically, polymer solubility is critical to the overall performance capability of the photoresist formulation. While several theories describe polymer solvent solubility, the most common industrially applied method is Hansen's solubility parameters. Hansen's method, based on regular solution theory, describes a solute's ability to dissolve in a solvent or solvent blend using four physical properties determined experimentally through regression of solubility data in many known solvents. The four physical parameters are dispersion, polarity, hydrogen bonding, and radius of interaction. Using these parameters a relative cohesive energy difference (RED), which describes a polymer's likelihood to dissolve in a given solvent blend, may be calculated. Leveraging a high throughput workflow to prepare and analyze the thousands of samples necessary to calculate the Hansen's solubility parameters from many different methacrylate-based polymers, we compare the physical descriptors to reveal a large range of polarities and hydrogen bonding. Further, we find that Hansen's model correctly predicts the soluble/insoluble state of 3-component solvent blends where the dispersion, polar, hydrogen-bonding, and radius of interaction values were determined through regression of experimental values. These modeling capabilities have allowed for optimization of the photoresist solubility from initial blending through application providing valuable insights into the nature of photoresist.

  11. Comment on ;Hydromagnesite solubility product and growth kinetics in aqueous solution from 25 to 75 °C; by Gautier, Q., Benezeth, P., Mavromatis, V., and Schott, J.

    Science.gov (United States)

    Xiong, Yongliang

    2017-09-01

    Gautier et al. (2014) recently published their determination of hydromagnesite solubility constant and hydromagnesite growth kinetics. Although their raw data appear to be of high quality, there is an oversight in their calculations of the hydromagnesite solubility constants given the solution compositions in their experiments. The oversight lies in the fact that they did not consider the constraint of simultaneous equilibrium with brucite. This oversight causes their newly calculated equilibrium constant for hydromagnesite to be discordant with the literature values (Königsberger et al., 1992; Xiong, 2011).

  12. Liquid chromatographic determination of urea in water-soluble urea-formaldehyde fertilizer products and in aqueous urea solutions: collaborative study.

    Science.gov (United States)

    Hojjatie, Michael M; Abrams, Dean E; Parham, Thomas M; Balthrop, J; Beine, R; Dickinson, V; Hartshorn, J; Herald, S; Latimer, G; Padmore, J; Pleasants, S; Riter, K; Roser, R; Schmunck, G; Sensmeier, R; Smith, V; Taylor, L; Volgas, G

    2004-01-01

    Water soluble urea-formaldehyde (UF) fertilizers, manufactured by complex reaction of urea and formaldehyde, typically contain varying amounts of unreacted urea. A liquid chromatography method for the analysis of urea in these products, and in aqueous urea solutions, was collaboratively studied. An amine chromatography column was used to separate the unreacted urea from numerous UF reaction products present in these liquid fertilizers. Unreacted urea was determined by using external urea standards with UV detection at 195 nm. The standards and test samples were prepared in the mobile phase of 85% (v/v) acetonitrile in water. Ten laboratories analyzed 5 different UF-based commercial products containing unreacted urea in the range of 6 to 17% by weight, and 5 different concentrations of urea in water equivalent to commercial products of that nature. The aqueous urea solutions contained 2-20% urea (w/w). The range of s(R) values for the 5 UF-based commercial fertilizers was 0.49-1.02 and the %RSD(R) was 1.94-6.14. The s(R) range for the 5 urea solutions was 0.10 to 0.79 and the %RSD(R) range was 2.54 to 4.88. The average recovery of urea from the aqueous urea solutions was 96-103%. Therefore, this method is capable of monitoring urea nitrogen manufacturers' label claims and total nitrogen claims in those cases where urea is the sole source of plant food nitrogen. Based on the collaborative study data, the authors recommend this method be approved for AOAC Official First Action status.

  13. Behavior of Aqueous Electrolytes in Steam Cycles - The Final Report on the Solubility and Volatility of copper(I) and Copper(II) Oxides

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, Donald [ORNL; Benezeth, Pascale [Laboratoire des Mecanismes et Transferts en Geologie, Toulouse, France; Simonson, J Michael {Mike} [ORNL

    2004-05-01

    Measurements were completed on the solubility of cupric and cuprous oxides in liquid water and steam at controlled pH conditions from 25 to 400 C (77 to 752 F). The results of this study have been combined with those reported from this laboratory in two previous EPRI reports to provide a complete description of the solubility of these oxides and the speciation of copper dissolved in liquid water and steam as a function of oxidation state, temperature, pH, and in the case of steam, pressure. These constitute the first set of reliable data for cuprous oxide solubility over this range of conditions. For the more intensively studied CuO case, agreement was found between our results and those of previous studies of its solubility in steam, whereas only partial agreement was evident for its solubility in liquid water. For both oxides this disagreement often amounted to orders of magnitude. The solubility of cuprous oxide is somewhat lower than that of CuO at ambient conditions, except as very high pH. However, by 350 C (662 F), Cu{sub 2}O is the more soluble phase. At 100 C (212 F) and above, the logarithm of the solubility of both phases decreases linearly with increasing pH to a minimum value then sharply increases linearly with pH. In other words, above 100 C the solubility of both oxides become highly pH dependent. In fact at constant pH during startup, very high copper concentrations can be reached in the boiler water, more than an order of magnitude above those at ambient or operating temperatures. The enhancing effect of added ammonia on the solubility of both oxides is most significant at low temperatures and is much greater for cuprous oxide. Consequently, the mobility of copper is affected significantly under AVT startup conditions. The oxidation of copper metal and presumably cuprous oxide by addition of air-saturated makeup water can lead to much higher copper concentrations than equilibrium with cupric oxide would allow, but the presence of both copper metal

  14. High shear treatment of concentrates and drying conditions influence the solubility of milk protein concentrate powders.

    Science.gov (United States)

    Augustin, Mary Ann; Sanguansri, Peerasak; Williams, Roderick; Andrews, Helen

    2012-11-01

    The solubility of milk protein concentrate (MPC) powders was influenced by the method used for preparing the concentrate, drying conditions, and the type of dryer used. Increasing total solids of the ultrafiltered concentrates (23% total solids, TS) by diafiltration to 25% TS or evaporation to 31% TS decreased the solubility of MPC powders (80-83% protein, w/w dry basis), with ultrafiltration followed by evaporation to higher total solids having the greater detrimental effect on solubility. High shear treatment (homogenisation at 350/100 bar, microfluidisation at 800 bar or ultrasonication at 24 kHz, 600 watts) of ultrafiltered and diafiltered milk protein concentrates prior to spray drying increased the nitrogen solubility of MPC powders (82% protein, w/w dry basis). Of the treatments applied, microfluidisation was the most effective for increasing nitrogen solubility of MPC powders after manufacture and during storage. Manufacture of MPC powders (91% protein, w/w dry basis) prepared on two different pilot-scale dryers (single stage or two stage) from milk protein concentrates (20% TS) resulted in powders with different nitrogen solubility and an altered response to the effects of microfluidisation. Microfluidisation (400, 800 and 1200 bar) of the concentrate prior to drying resulted in increased long term solubility of MPC powders that were prepared on a single stage dryer but not those produced on a two stage spray dryer. This work demonstrates that microfluidisation can be used as a physical intervention for improving MPC powder solubility. Interactions between the method of preparation and treatment of concentrate prior to drying, the drying conditions and dryer type all influence MPC solubility characteristics.

  15. Aqueous soluble tetrazolium/formazan MTS as an indicator of NADH- and NADPH-dependent dehydrogenase activity.

    Science.gov (United States)

    Dunigan, D D; Waters, S B; Owen, T C

    1995-10-01

    Recently a new tetrazolium was described for the use of monitoring cell viability in culture. This tetrazolium, commonly referred to as MTS [3-(4,5-dimethylthiazol-2-yl)- 5-(3-carboxymethonyphenol)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt], has the unusual property that it can be reduced to a water-soluble formazan. beta-Nicotinamide adenine dinucleotide/reduced (NADH) and beta-nicotinamide adenine dinucleotide phosphate/reduced (NADPH) are examples of physiologically important reducing agents. In cell-free studies, MTS was reduce to the soluble formazan in the presence of NADH and NADPH, and reaction were compared to those with dithiothreitol (DTT) or 2-mercaptoethanol (2-ME). The efficiency of these reactions was enhanced 1000-fold by the presence of phenazine methosulfate. Selectivity in the electron transfer from NADPH was slightly greater than NADH, and NADPH or NADH was much greater than the thiols DTT or 2-ME. Generation of either NADH or NADPH in solution by malate dehydrogenase or isocitrate dehydrogenase, respectively, was monitored by the MTS reduction reaction. The rate of formazan formation was comparable to the formation of NADH or NADPH. This system represents a useful tool for evaluating reaction kinetics in solutions of NAD- or NADP-dependent dehydrogenase enzymes, and these reactions can be performed in typical biological buffers containing reducing agents without significant interference to the MTS/formazan system.

  16. PLUTONIUM SOLUBILITY IN HIGH-LEVEL WASTE ALKALI BOROSILICATE GLASS

    Energy Technology Data Exchange (ETDEWEB)

    Marra, J.; Crawford, C.; Fox, K.; Bibler, N.

    2011-01-04

    The solubility of plutonium in a Sludge Batch 6 (SB6) reference glass and the effect of incorporation of Pu in the glass on specific glass properties were evaluated. A Pu loading of 1 wt % in glass was studied. Prior to actual plutonium glass testing, surrogate testing (using Hf as a surrogate for Pu) was conducted to evaluate the homogeneity of significant quantities of Hf (Pu) in the glass, determine the most appropriate methods to evaluate homogeneity for Pu glass testing, and to evaluate the impact of Hf loading in the glass on select glass properties. Surrogate testing was conducted using Hf to represent between 0 and 1 wt % Pu in glass on an equivalent molar basis. A Pu loading of 1 wt % in glass translated to {approx}18 kg Pu per Defense Waste Processing Facility (DWPF) canister, or about 10X the current allowed limit per the Waste Acceptance Product Specifications (2500 g/m{sup 3} of glass or about 1700 g/canister) and about 30X the current allowable concentration based on the fissile material concentration limit referenced in the Yucca Mountain Project License Application (897 g/m{sup 3}3 of glass or about 600 g Pu/canister). Based on historical process throughput data, this level was considered to represent a reasonable upper bound for Pu loading based on the ability to provide Pu containing feed to the DWPF. The task elements included evaluating the distribution of Pu in the glass (e.g. homogeneity), evaluating crystallization within the glass, evaluating select glass properties (with surrogates), and evaluating durability using the Product Consistency Test -- Method A (PCT-A). The behavior of Pu in the melter was evaluated using paper studies and corresponding analyses of DWPF melter pour samples.The results of the testing indicated that at 1 wt % Pu in the glass, the Pu was homogeneously distributed and did not result in any formation of plutonium-containing crystalline phases as long as the glass was prepared under 'well-mixed' conditions

  17. Chemical synthesis and characterization of highly soluble conducting polyaniline in the mixtures of common solvents

    Directory of Open Access Journals (Sweden)

    Zeghioud Hichem

    2015-01-01

    Full Text Available This work presents the synthesis and characterization of soluble and conducting polyaniline PANI-PIA according to chemical polymerization route. This polymerization pathway leads to the formation of poly(itaconic acid doped polyaniline salts, which are highly soluble in a number of mixtures between organic common polar solvents and water, the solubility reaches 4 mg mL-1. The effect of synthesis parameters such as doping level on the conductivity and the study of solubility and other properties of the resulting PANI salts were also undertaken. The maximum of conductivity was found equal to 2.48×10-4 S cm-1 for fully protonated PANI-EB. In addition, various characterizations of the synthesized materials were also done with the help of viscosity measurements, UV-vis spectroscopy, XRD, FTIR and finally TGA for the thermal properties behaviour.

  18. Synthesis of highly luminescent Mn:ZnSe/ZnS nanocrystals in aqueous media.

    Science.gov (United States)

    Fang, Zheng; Wu, Ping; Zhong, Xinhua; Yang, Yong-Ji

    2010-07-30

    High-quality water-dispersible Mn(2+)-doped ZnSe core/ZnS shell (Mn:ZnSe/ZnS) nanocrystals have been synthesized directly in aqueous media. Overcoating a high bandgap ZnS shell around the Mn:ZnSe cores can bring forward an efficient energy transfer from the ZnSe host nanocrystals to the dopant Mn. The quantum yields of the dopant Mn photoluminescence in the as-prepared water-soluble Mn:ZnSe/ZnS core/shell nanocrystals can be up to 35 +/- 5%. The optical features and structure of the obtained Mn:ZnSe/ZnS core/shell nanocrystals have been characterized by UV-vis, PL spectroscopy, TEM, XRD and ICP elementary analysis. The influences of various experimental variables, including the Mn concentration, the Se/Zn molar ratio as well as the kind and amount of capping ligand used in the core production and shell deposition process, on the luminescent properties of the obtained Mn:ZnSe/ZnS nanocrystals have been systematically investigated.

  19. Aqueous-Phase Catalytic Chemical Reduction of p-Nitrophenol Employing Soluble Gold Nanoparticles with Different Shapes

    Directory of Open Access Journals (Sweden)

    Francyelle Moura de Oliveira

    2016-12-01

    Full Text Available Gold nanoparticles with different shapes were prepared and used as catalysts in the reduction of p-nitrophenol (PNP in the aqueous phase and in the presence of sodium borohydride (NaBH4. Parameters such as the reaction temperature, substrate/NaBH4 molar ratio, and substrate/gold molar ratio were tested and evaluated. In this paper, we compare the catalytic reactivities of gold nanorods (AuNRs and gold nanospheres (AuNSs, both synthesized by the seed-mediated method in the presence of cetyltrimethyl ammonium bromide (CTAB. Physical-chemical parameters such as the apparent rate constant (kapp and activation energy (Ea of the reactions were obtained for both systems. We observed that the catalytic system based on AuNRs is the most active. These colloidal dispersions were investigated and fully characterized by ultraviolet-visible absorption spectroscopy (UV–Vis and transmission electron microscopy (TEM.

  20. Solubility of Malladrite Na2SiF6 and K2SiF6 in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Skafi M.

    2013-09-01

    Full Text Available The water activities of binary solutions Na2SiF6-H2O and K2SiF6-H2O are measured from dilution to saturation using the hygrometric method at temperature 353 K. From these experimental data, the activity coefficients of solute were calculated using parameters of ionic interaction model. These coefficients are used to predict the solubility products of the K°sp, the free energy ΔG°diss of dissolution and also the characterization of the precipitated phases to saturation of the system containing Na2SiF6 or K2SiF6. The analyzed of solid phase obtained from saturated solution is made by Xray- diffraction.

  1. Recovery and characterization of Balanites aegyptiaca Del. kernel proteins. Effect of defatting, air classification, wet sieving and aqueous ethanol treatment on solubility, digestibility, amino acid composition and sapogenin content.

    Science.gov (United States)

    Mohamed, A M; Wolf, W; Spiess, W E

    2000-02-01

    In order to find alternative protein sources in African regions where protein deficiency in nutrition is prevailing, solubility, in-vitro digestibility, amino acid composition and chemical score of Balanites aegyptiaca Del. kernel proteins were investigated as a function of different processing steps including defatting, air classification, wet sieving and aqueous ethanol treatment. Air classification delivered a fine fraction of 58.1% of the total protein. Applying a wet sieving process, a protein concentrate of 72.9% protein content was achieved but the recovery was very low (35.6%). However, in case of isoelectric precipitation followed by aqueous ethanol treatment both protein content (78.2%) and recovery (53.7%) were high. Data concerning the chemical score revealed, that lysine content of the defatted kernel flour amounted to 74.2% of the recommended FAO/WHO standard level. In-vitro protein digestibility was found to be higher than of legume proteins. The digestible protein of the full fat flour, defatted flour, air classified and wet sieved fine fractions and protein concentrate were 91.9, 93.7, 82.0, 86.4 and 94.2%, respectively. The sapogenin content per 100 g protein of the investigated protein preparations was significantly lower (46% to 62%) than of the initial material (oilcake).

  2. Highly potent soluble amyloid-β seeds in human Alzheimer brain but not cerebrospinal fluid

    Science.gov (United States)

    Kaeser, Stephan A.; Maia, Luis F.; Portelius, Erik; Pinotsi, Dorothea; Kaminski, Clemens F.; Winkler, David T.; Maetzler, Walter; Keyvani, Kathy; Spitzer, Philipp; Wiltfang, Jens; Kaminski Schierle, Gabriele S.; Zetterberg, Henrik; Staufenbiel, Matthias; Jucker, Mathias

    2017-01-01

    The soluble fraction of brain samples from patients with Alzheimer’s disease contains highly biologically active amyloid-β seeds. In this study, we sought to assess the potency of soluble amyloid-β seeds derived from the brain and cerebrospinal fluid. Soluble Alzheimer’s disease brain extracts were serially diluted and then injected into the hippocampus of young, APP transgenic mice. Eight months later, seeded amyloid-β deposition was evident even when the hippocampus received subattomole amounts of brain-derived amyloid-β. In contrast, cerebrospinal fluid from patients with Alzheimer’s disease, which contained more than 10-fold higher levels of amyloid-β peptide than the most concentrated soluble brain extracts, did not induce detectable seeding activity in vivo. Similarly, cerebrospinal fluid from aged APP-transgenic donor mice failed to induce cerebral amyloid-β deposition. In comparison to the soluble brain fraction, cerebrospinal fluid largely lacked N-terminally truncated amyloid-β species and exhibited smaller amyloid-β-positive particles, features that may contribute to the lack of in vivo seeding by cerebrospinal fluid. Interestingly, the same cerebrospinal fluid showed at least some seeding activity in an in vitro assay. The present results indicate that the biological seeding activity of soluble amyloid-β species is orders of magnitude greater in brain extracts than in the cerebrospinal fluid. PMID:25212850

  3. Preparation of water-soluble graphene nanoplatelets and highly conductive films

    KAUST Repository

    Xu, Xuezhu

    2017-08-11

    This paper tackles the challenge of preparation stable, highly concentrated aqueous graphene dispersions. Despite tremendous recent interest, there has been limited success in developing a method that ensures the total dispersion of non-oxidized, defect-free graphene nanosheets in water. This study successfully demonstrates that few-layer graphene nanoplatelets (GNPs) can form highly concentrated aqueous colloidal solutions after they have been pretreated in a low-concentration inorganic sodium-hypochlorite and sodium-bromide salted aqueous solvent. This method retains the graphitic structure as evidenced by nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Vacuum-filtrated freestanding films demonstrate an electrical conductivity as high as 3000 S m−1. This dispersion technique is believed to be applicable not only for GNPs, but also for dispersing other types of graphitic materials, including fullerenes, single/double/multi-walled carbon nanotubes, graphene nanoribbons and etc.

  4. Dynamics of a photochromic spiropyran under aqueous conditions

    Directory of Open Access Journals (Sweden)

    Heckel A.

    2013-03-01

    Full Text Available The dynamics of a water soluble spiropyran is investigated by means of femtosecond transient absorption spectroscopy in the visible and infrared spectral range revealing an ultrafast reversible switching behavior under aqueous conditions with a high fatigue resistance.

  5. Hematite solubility in NaCl- and CaSiO3-bearing aqueous fluids at 10 kbar and 800 C

    Science.gov (United States)

    Wykes, J. L.; Manning, C. E.

    2005-12-01

    A distinguishing characteristic of arc-related magmas is their high oxidation state, manifest as elevated Fe3+/Fe(total) relative to OIB and MORB. However, there is no consensus on the process and agents responsible for arc-magma oxidation. The subducting slab represents an obvious source of oxidized material, particularly lithologies rich in ferric iron-bearing minerals and sulfates produced through seawater interaction. Fe3+ and SO4}2- represent the most readily available agents for mantle-wedge oxidation. Hydrous fluids and brines equilibrated with these oxidized portions of the slab may be effective oxidizing agents. To assess this possibility, we measured the solubility of hematite in NaCl-H2O fluids at 10 kbar and 800°C. Experiments were conducted in a piston-cylinder apparatus with graphite-NaCl furnace assemblies. Solubility was determined by weight loss of either sintered reagent-grade hematite pellets or rounded specular hematite fragments (1 wt% TiO2). The ultra-fine grained reagent hematite tended to recrystallize during experiments; however, in some cases the final pellets were quite friable, leading to material loss during weighing. These experiments were discounted because their weight changes were spurious. Two methods were employed to control fO2. Either a sealed Mn2O3-filled Pt capsule was run inside the fluid filled outer capsule, buffering at the Mn2O3-Mn3O4 equilibrium, or the outer capsule was packed in MnO2 powder inside the graphite heater assembly, acting as a H2 sink. External MnO2 resulted in some recrystallization of the Pt capsules. However, hematite solubility was identical for both methods, suggesting both techniques control fO2 to a similar degree. The solubility of hematite in H2O-NaCl fluids was measured from 0-72 wt% NaCl. Hematite solubility in pure H2O was 5.5×10-4 molal total Fe, with a detection limit of 8.3×10-5. With increasing NaCl conentration, hematite solubility increased from ~0.001 molal total Fe at 13 wt% NaCl to

  6. Water-Soluble Fluorescent CdTe/ZnSe Core/Shell Quantum Dot: Aqueous Phase Synthesis and Cytotoxicity Assays.

    Science.gov (United States)

    Li, Yansheng; Wang, Wenqian; Zhao, Dan; Chen, Peng; Du, Hongwu; Wen, Yongqiang; Zhang, Xueji

    2015-06-01

    In this manuscript, we demonstrate a novel, facile and environmentally friendly method to directly obtain CdTe/ZnSe core/shell QDs in the aqueous phase based on the method of epitaxial growth of ZnSe shells on CdTe cores. The ZnSe shell and the capping reagent glutathione of the CdTe/ZnSe core/shell QDs greatly increased the biocompatibility and stability of the original CdTe cores. The optical property of the as-prepared CZ QDs could be controlled by precisely adjusting the size of CdTe cores, which showed broad emission spectra from 530 to 688 nm. The crystalline structure of the CZ QDs was extensively characterized by XRD, TEM and HRTEM, etc. Furthermore, since there were several functional groups on glutathione molecules, the QDs could be potentially used for connecting other functional small molecules, biomolecules or nanoparticles. Such QDs have bright future perspectives in the development biological and nanomedical fields.

  7. Temperature-dependent photoluminescence of highly luminescent water-soluble CdTe quantum dots

    Institute of Scientific and Technical Information of China (English)

    Ji Wei Liu; Yu Zhang; Cun Wang Ge; Yong Long Jin; Sun Ling Hu; Ning Gu

    2009-01-01

    Highly luminescent water-soluble CdTe quantum dots (QDs) have been synthesized with an electrogenerated precursor. The obtained CdTe QDs can possess good crystallizability, high quantum yield (QY) and favorable stability. Furthermore, a detection system is designed firstly for the investigation of the temperature-dependent PL of the QDs.

  8. A family of E. coli expression vectors for laboratory scale and high throughput soluble protein production

    Directory of Open Access Journals (Sweden)

    Bottomley Stephen P

    2006-03-01

    Full Text Available Abstract Background In the past few years, both automated and manual high-throughput protein expression and purification has become an accessible means to rapidly screen and produce soluble proteins for structural and functional studies. However, many of the commercial vectors encoding different solubility tags require different cloning and purification steps for each vector, considerably slowing down expression screening. We have developed a set of E. coli expression vectors with different solubility tags that allow for parallel cloning from a single PCR product and can be purified using the same protocol. Results The set of E. coli expression vectors, encode for either a hexa-histidine tag or the three most commonly used solubility tags (GST, MBP, NusA and all with an N-terminal hexa-histidine sequence. The result is two-fold: the His-tag facilitates purification by immobilised metal affinity chromatography, whilst the fusion domains act primarily as solubility aids during expression, in addition to providing an optional purification step. We have also incorporated a TEV recognition sequence following the solubility tag domain, which allows for highly specific cleavage (using TEV protease of the fusion protein to yield native protein. These vectors are also designed for ligation-independent cloning and they possess a high-level expressing T7 promoter, which is suitable for auto-induction. To validate our vector system, we have cloned four different genes and also one gene into all four vectors and used small-scale expression and purification techniques. We demonstrate that the vectors are capable of high levels of expression and that efficient screening of new proteins can be readily achieved at the laboratory level. Conclusion The result is a set of four rationally designed vectors, which can be used for streamlined cloning, expression and purification of target proteins in the laboratory and have the potential for being adaptable to a high

  9. Soluble, High Molecular Weight Polysilsesquioxanes with Carboxylate Functionalities

    Energy Technology Data Exchange (ETDEWEB)

    RAHIMIAN,KAMYAR; LOY,DOUGLAS A.; WHEELER,DAVID R.

    2000-07-14

    Trialkoxysilyl-containing monomers of the type (RO){sub 3}Si(CH{sub 2}){sub 3}C(O)OtBu (R = Me, Et) were prepared by hydrosilation of the corresponding vinylic tert-butyl esters CH{sub 3}CHCH{sub 2}C(O)OtBu. Acid- or base-catalyzed polymerization of the monomers leads to very high molecular weight polymers with relatively narrow polydispersities. The polymerization results in complete condensation of the alkoxy groups while the tert-butyl ester functionality remains fully intact. Partial or full deprotection of the tert-butyl group can easily be achieved to yield the corresponding carboxylic acid polymers. The ester and carboxylic acid functionalities of these new materials allow for their potential use in a variety of applications such as scavenging of heavy metals.

  10. Highly water soluble nanoparticles as a draw solute in forward osmosis for the treatment of radioactive liquid waste

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Heeman; Choi, Hye Min; Jang, Sungchan; Seo, Bumkyoung; Lee, Kune Woo; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    . In this study, we introduced highly water-soluble hyperbranched caroboxylated polyglycerol-coated magnetic nanoparticles (CPG-MNPs). It is known that the highly branched, globular architecture of PG significantly increase solubility compared to linear polymer and they are eco-friendly. The CPG-MNPs showed no aggregate of particles in water even after placing external magnet, and exhibited a high water flux in FO process. The CPG-MNPs are, therefore, potentially useful as a draw solute in FO processes. The operation of nuclear pressurized water reactors (PWRs) results in numerous radioactive waste streams which vary in radioactivity content. Most PWR stations have experienced leakages of boric acid into liquid radioactive waste systems. These wastes contain about 0.3∼0.8 wt% of boric acid. It is known that reverse osmosis (RO) membrane can eliminate boron at high pH and boron of 40∼90% can be removed by RO membrane in pH condition. RO uses hydraulic pressure to oppose, and exceed, the osmotic pressure of an aqueous feed solution containing boric acid. Forward osmosis (FO), a low energy technique based on membrane technologies, has recently garnered attention for its utility in wastewater treatment and desalination applications. In the FO process, water flows across a semi-permeable membrane from a solution with a low osmotic pressure (the feed solution) to a solution with a high osmotic pressure (the draw solution). The driving force in FO processes is provided by the osmotic gradient between the two solutions. Low energy costs and low degrees of membrane fouling are two of the advantages conveyed by FO processes over other processes, such as reverse osmosis processes that rely on a hydraulic pressure driving force. However, the challenges of FO still lie in the fabrication of eligible FO membranes and the readily separable draw solutes of high osmotic pressures. Superparamagnetic Fe3O4 nanoparticles can be separated from water by an external magnet field

  11. The effect of lipid and aqueous solubilities on flux of nicotinic acid esters from water through silicone membrane.

    Science.gov (United States)

    Synovec, Jennifer; Wasdo, Scott C; Sloan, Kenneth B

    2013-09-01

    The maximum fluxes (J(M)) of nicotinic acid esters (NAE) across silicone membranes from water (J(MPAQ)) have been measured to determine how well they correlate with J(M) of NAE across human skin from water in vitro (J(MHAQ)) and in vivo (J(MHAQ1)) and with J(M) of NAE across hairless mouse skin from water (J(MMAQ)). The NAE were all commercially available. Solubilities in water (S(AQ)), isopropyl myristate (S(IPM)) and octanol (S(OCT)) were obtained from literature sources. J(MPAQ) were measured at saturation for all the esters except the methyl ester. In that case, flux was measured at a concentration (C) less than saturation (J(PAQ)) and converted to J(MPAQ) = (J(PAQ))(S(AQ)/C(AQ)). J(MPAQ) values predicted from the previously reported coefficients to the parameters in the Roberts-Sloan (RS) equation (PRE J(MPAQ)) were substantially lower than the experimental J(MPAQ) values (EXP J(MPAQ)) values obtained here. The EXP J(MPAQ) were incorporated into the previous J(MPAQ) database and new coefficients were obtained: x = -1.837; y = 0.742; z = 0.00435; r² = 0.86. Correlation of J(MPAQ) values with J(MHAQ), J(MHAQ1), and J(MMAQ) values show the same trend as the J(MPAQ) values. The inclusion of the NAE n = 6 data into the previous n = 32 database for the permeation of the prodrugs through a silicone membrane from water (J(MPAQ)) greatly improved the fit of the n = 38 database to the RS equation: r² = 0.86 vs r² = 0.77. The correlation between log J(MHAQ) and log J(MPAQ) gave r² = 0.98. This suggests that J(MPAQ) values are good predictors of J(MHAQ) values.

  12. Solubility of guaifenesin in the presence of common pharmaceutical additives.

    Science.gov (United States)

    Mani, Narasimhan; Jun, H W; Beach, J Warren; Nerurkar, Jayanti

    2003-01-01

    The aqueous solubility of guaifenesin, a highly water-soluble drug, in the presence of salts, sugars, and cosolvents was determined at 25 degrees C and 40 degrees C. The solubility of drug at both temperatures was reduced with increasing concentrations of salts and sugars. The extent of reduction in drug solubility was dependent on the type of salts and sugars used. The salting-out coefficient of additives was calculated by plotting log-linear solubility profiles of the drug against the concentrations of the additives. The solubility of guaifenesin, a neutral compound, was found to be higher at lower pH values, which could be due to hydrogen-bonding effects. At 25 degrees C, glycerin, PEG 300, and propylene glycol increased the solubility of drug at low solvent concentrations while the solubility was reduced at high concentrations. At 40 degrees C, the solubility of drug was reduced at all concentrations of cosolvents. The thermodynamic events accompanying the solubility process were discussed to explain the solubility phenomena observed in the presence of additives. The reduced aqueous solubility of guaifenesin in the presence of additives greatly improved the entrapment of drug into controlled-release wax microspheres.

  13. Cell Model of In-cloud Scavenging of Highly Soluble Gases

    Science.gov (United States)

    Baklanov, A.; Elperin, T.; Fominykh, A.; Krasovitov, B.

    2012-04-01

    Transport of soluble gases in clouds is an integral part of the atmospheric transport of gases and is important for understanding the global distribution pattern of soluble trace gases. In the present study we investigated mass transfer during absorption of highly soluble gases such as hydrogen peroxide H2O2 and nitric acid HNO3 by stagnant cloud droplets in the presence of inert admixtures. Diffusion interactions between droplets, caused by the overlap of depleted of soluble gas regions around the neighboring droplets, are taken into account in the approximation of a cellular model of a gas-droplet suspension whereby a suspension is viewed as a periodic structure consisting of the identical spherical cells with periodic boundary conditions at the cell boundary. Using this model we determined temporal and spatial dependencies of the concentration of the soluble trace gas in a gaseous phase and in a droplet and calculated the dependence of the scavenging coefficient on time. It is shown that scavenging of highly soluble gases by cloud droplets leads to essential decrease of soluble trace gas concentration in the interstitial air. We found that scavenging coefficient for gas absorption by cloud droplets remains constant and sharply decreases only at the final stage of absorption. This assertion implies the exponential time decay of the average concentration of the soluble trace gas in the gaseous phase and can be used for the parameterization of gas scavenging by cloud droplets in the atmospheric transport modeling. In the calculations we employed gamma size distribution of cloud droplets. It was shown that despite of the comparable values of Henry's law constants for the hydrogen peroxide and the nitric acid, the nitric acid is scavenged more effectively by cloud than the hydrogen peroxide due to a major affect of the dissociation reaction on nitric acid scavenging. We obtained also the analytical expressions for the "equilibrium values" of concentration of the

  14. Microscopic views of drug solubility

    OpenAIRE

    Bondesson, Laban

    2006-01-01

    The development of computational models for predicting drug solubility has increased drastically during the last decades. Nevertheless these models still have diffculties to estimate the aqueous solubility as accurate as desired. In this thesis di erent aspects that are known to have a large impact on the aqueous solubility of a molecule have been studied in detail using various theoretical methods with intension to provide microscopic view on drug solubility. The rst aspect studied is the hy...

  15. Prediction of oxygen solubility in pure water and brines up to high temperatures and pressures

    Science.gov (United States)

    GENG, Ming; DUAN, Zhenhao

    2010-10-01

    A thermodynamic model is presented to calculate the oxygen solubility in pure water (273-600 K, 0-200 bar) and natural brines containing Na +, K +, Ca 2+, Mg 2+, Cl -, SO 42-, over a wide range of temperature, pressure and ionic strength with or close to experimental accuracy. This model is based on an accurate equation of state to calculate vapor phase chemical potential and a specific particle interaction model for liquid phase chemical potential. With this approach, the model can not only reproduce the existing experimental data, but also extrapolate beyond the data range from simple aqueous salt system to complicated brine systems including seawater. Compared with previous models, this model covers much wider temperature and pressure space in variable composition brine systems. A program for this model can be downloaded from the website: http://www.geochem-model.org.

  16. A comparative QSPR study on aqueous solubility of polycyclic aromatic hydrocarbons by GA-SVM, GA-RBFNN and GA-PLS

    Institute of Scientific and Technical Information of China (English)

    Jun QI; Jia WEI; Changhong SUN; Tao PAN

    2011-01-01

    A novel method to develop quantitative structure-property relationship(QSPR)models of organic contaminants was proposed based on genetic algorithm (GA)and support vector machine(SVM).GA was used to perform the variable selection and SVM was used to construct QSPR models.In this study,GA-SVM was applied to develop the QSPR model for aqueous solubility (Sw,mol·L-1)of polycyclic aromatic hydrocarbons (PAHs).The R2(0.98)of the model developed by GASVM indicated a good predictive precision for 1g Sw values of PAHs.According to leave-one-out(LOO)cross validation,the results of GA-SVM were compared with those of genetic algorithm-radial based function neural network(GA-RBFNN)and genetic algorithm-partial leastsquares(GA-PLS)regression.The comparisons showed that the cross validation correlation coefficient(Q2LOO =0.92)and root mean square error of LOO cross validation (RMSELoo =0.49)of GA-SVM were the highest and lowest,respectively,which illustrated that GA-SVM was more suitable to develop QSPR model for the lg Sw values of PAHs than GA-RBFNN and GA-PLS.

  17. Comparison of high performance liquid chromatography and enzymatic analysis of soluble carbohydrates in loblolly pine

    Science.gov (United States)

    Patricia L. Faulkner; Michele M. Schoeneberger; Kim H. Ludovici

    1993-01-01

    Foliar tissue was collected from a field study designed to test impacts of atmospheric pollutants on loblolIy pine (Pinus taeda L.) seedlings. Standard enzymatic (ENZ) and high performance liquid chromatography (HPLC) methods were used to analyze the tissue for soluble sugars. A comparison of the methods revealed no significant diffennces in accuracy...

  18. Synthesis and Optoelectronic Properties of Nanometer-Sized and Highly Soluble Homocoupled Oligodiacetylenes

    NARCIS (Netherlands)

    Pilzak, G.S.; Baggerman, J.; Lagen, van B.; Posthumus, M.A.; Sudhölter, E.J.R.; Zuilhof, H.

    2009-01-01

    Color and shape of oligodiacetylenes: We synthesized a series of highly soluble homocoupled oligodiacetylenes (HODAs). The color of these oligomers is dependent on the molecular length and aggregation state (see picture). The optical properties of these materials were studied by using both

  19. Highly water-soluble multi-walled carbon nanotubes amine-functionalized by supercritical water oxidation.

    Science.gov (United States)

    Chun, Kyoung-Yong; Moon, In-Kyu; Han, Joo-Hee; Do, Seung-Hoe; Lee, Jin-Seo; Jeon, Seong-Yun

    2013-11-07

    Multi-walled carbon nanotubes (MWNTs) have been amine-functionalized by eco-friendly supercritical water oxidation. The facilely functionalized MWNTs have high solubility (~84 mg L(-1)) in water and 78% transmittance at 30-fold dilution. The Tyndall effect is also shown for several liquids.

  20. Soluble epoxide hydrolase in the generation and maintenance of high blood pressure in spontaneously hypertensive rats

    NARCIS (Netherlands)

    Koeners, Maarten P.; Wesseling, Sebastiaan; Ulu, Arzu; Lopez Sepulveda, Rocio; Morisseau, Christophe; Braam, Branko; Hammock, Bruce D.; Joles, Jaap A.

    2011-01-01

    Koeners MP, Wesseling S, Ulu A, Sepulveda RL, Morisseau C, Braam B, Hammock BD, Joles JA. Soluble epoxide hydrolase in the generation and maintenance of high blood pressure in spontaneously hypertensive rats. Am J Physiol Endocrinol Metab 300: E691-E698, 2011. First published January 25, 2011; doi:

  1. High performance aqueous supercapacitor based on highly nitrogen-doped carbon nanospheres with unimodal mesoporosity

    Science.gov (United States)

    Sun, Fei; Gao, Jihui; Pi, Xinxin; Wang, Lijie; Yang, Yuqi; Qu, Zhibin; Wu, Shaohua

    2017-01-01

    Herein, we report a high performance aqueous supercapacitor which is made of highly nitrogen-doped carbon nanospheres (NRMCs) with unimodal mesoporosity. An aerosol-assisted spraying process is employed to obtain the nano-sized NRMC particles possessing large surface areas, high pore volumes and ultra-high N doping levels (14.51%-20.55%). Evaluated as supercapacitor electrode, the optimized NRMC exhibits excellent performance for aqueous electrical double layer capacitors with high material-level specific capacitance (432 F g-1 at 1 A g-1), excellent rate performance (205 F g-1 at a high current density of 100 A g-1) and high cycling stability. The constructed symmetric supercapacitor delivers high energy densities of 9.2 Wh kg-1 and 4 Wh kg-1 at power densities of 0.11 kW kg-1 and 23.24 kW kg-1, respectively. Moreover, the effect of N specie distribution on the rate performance is also demonstrated, which highlights the important role of tuning the N doping patterns on enhancing the supercapacitive performances of carbon materials.

  2. High expression level of soluble SARS spike protein mediated by adenovirus in HEK293 cells

    Institute of Scientific and Technical Information of China (English)

    Fei Zhong; Zhen-Yu Zhong; Shuang Liang; Xiu-Jin Li

    2006-01-01

    AIM: To develop a highly efficacious method for preparation of soluble SARS S-protein using adenovirus vector to meet the requirement for S-protein investigation.METHODS: The human adenovirus vector was used to express the soluble S-protein (corresponding to 1~1190 amino acids) fused with Myc/His tag using codon-optimized gene construct in HEK239 cells. The recombinant adenovirus bearing S-protein gene was generated by ligation method. The expressed S-protein with Myc/His tag was purified from culture medium with Ni-NTA agarose beads followed by dialysis. The S-protein was detected by Western blot and its biologic activity was analyzed by binding to Vero cells.RESULTS: Under the conditions of infection dose (MOI of 50) and expression time (48 h), the high-level expression of S-protein was obtained. The expression level was determined to be approximately 75 μg/106cells after purification. Purified soluble S-protein was readily detected by Western blot with anti-Myc antibody and showed the ability to bind to surface of Vero cells,demonstrating that the soluble S-protein could remain the biologic activity in the native molecule.CONCLUSION: The high-level expression of S-protein in HEK293 cells mediated by adenovirus can be achieved under the optimized expression conditions. The proteins possess the biologic activity, which lays a foundation for further investigation of S-protein biological function.

  3. Solubility of TcO2•xH2O(am) in the Presence of Gluconate in Aqueous Solution

    Energy Technology Data Exchange (ETDEWEB)

    Hess, Nancy J.; Xia, Yuanxian; Felmy, Andrew R.

    2006-09-15

    The solubility of TcO2•xH2O(am) in the presence of 0.01 M gluconate was measured over a wide range of hydroxide concentrations from pH = 3.5 to 5 M NaOH and as a function of gluconate concentration from 0.01 M to 0.5 M at a fixed hydroxide concentration of pH = 10.5. The presence of gluconate increased the solubility of TcO2•xH2O(am) by approximately two orders of magnitude over most of the pH range compared to the solubility of TcO2•xH2O(s) when no complexant is present. At extremely high hydroxide concentrations, above 3M NaOH, the Tc-gluconate solution species appears to polymerize and then precipitate as a white solid. At a fixed pH of 10.5, increasing the gluconate concentration by two orders of magnitude resulted in only a modest increase in measured Tc concentration. These initial results suggest the Tc-gluconate species may form polymerized species under basic conditions.

  4. Soluble iron dust export in the high altitude Saharan Air Layer

    Science.gov (United States)

    Ravelo-Pérez, L. M.; Rodríguez, S.; Galindo, L.; García, M. I.; Alastuey, A.; López-Solano, J.

    2016-05-01

    Every summer huge amounts of desert dust particles are exported from the hyperarid subtropical Sahara to the North Atlantic the so-called Saharan Air Layer (SAL), a dry, warm and dust-laden corridor that expands from the North African coast (1-5 km.a.s.l.) to the Americas above the marine boundary layer. Because of the potential impact of the dust deposited on the ocean on marine biogeochemistry and climate, we studied the Fe solubility (in seawater) of atmospheric aerosols samples directly collected in the SAL off the North African coast, i.e. the fresh aerosols recently exported from the Sahara in the SAL. The aerosol sampling was performed at ˜2400 m.a.s.l. in Izaña observatory in Tenerife island. In the total aerosols, we found low Fe concentrations and high fractional Fe solubility (FFS ˜2%) in the North Atlantic free troposphere airflows and high Fe concentrations and low FFS (˜0.7%) within the SAL; the resulting FFS versus total dust (or total Fe) plot shows a hyperbolic trend attributed to the conservative mixing of 'fine combustion aerosols' and 'lithogenic mineral dust'. We then focused on the soluble Fe in the SAL. Our results indicate that ˜70% of soluble Fe is associated with the dissolution of submicron dust particles, probably involving Fe-bearing clays. We found a FFS of submicron dust (˜6%) higher than that typically observed in submicron particles of soil dust samples (pollutants mixed with dust. Previous studies had focused on dust processing and changes of Fe solubility during the trans-Atlantic transport of dust in the SAL. We found that submicron dust exported off the coast of North Africa may have already experienced acid processing over the Sahara, i.e. before dust export to the Atlantic. Export of soluble submicron Fe dust and deposition of coarse and depleted in soluble Fe dust particles during the trans-Atlantic transport may account for the observed variability in dust, soluble Fe and FFS.

  5. Hydrodistillation-adsorption method for the isolation of water-soluble, non-soluble and high volatile compounds from plant materials.

    Science.gov (United States)

    Mastelić, J; Jerković, I; Blazević, I; Radonić, A; Krstulović, L

    2008-08-15

    Proposed method of hydrodistillation-adsorption (HDA) on activated carbon and hydrodistillation (HD) with solvent trap were compared for the isolation of water-soluble, non-soluble and high volatile compounds, such as acids, monoterpenes, isothiocyanates and others from carob (Certonia siliqua L.), rosemary (Rosmarinus officinalis L.) and rocket (Eruca sativa L.). Isolated volatiles were analyzed by GC and GC/MS. The main advantages of HDA method over ubiquitous HD method were higher yields of volatile compounds and their simultaneous separation in three fractions that enabled more detail analyses. This method is particularly suitable for the isolation and analysis of the plant volatiles with high amounts of water-soluble compounds. In distinction from previously published adsorption of remaining volatile compounds from distillation water on activated carbon, this method offers simultaneous hydrodistillation and adsorption in the same apparatus.

  6. Synthesis of Soluble Host Materials for Highly Efficient Red Phosphorescent Organic Light-Emitting Diodes.

    Science.gov (United States)

    Suh, Min Chul; Park, So-Ra; Cho, Ye Ram; Shin, Dong Heon; Kang, Pil-Gu; Ahn, Dong A; Kim, Hyung Suk; Kim, Chul-Bae

    2016-07-20

    New soluble host materials with benzocarbazole and triphenyltriazine moieties, 11-[3-(4,6-diphenyl-[1,3,5]triazin-2-yl)-phenyl]-11H-benzo[a]carbazole and 11-[3'-(4,6-diphenyl-[1,3,5]triazin-2-yl)-biphenyl-4-yl]-11H-benzo[a]carbazole, were synthesized for highly efficient red phosphorescent organic light-emitting diodes (PHOLED). Hole-transporting benzocarbazole moiety and electron transporting triphenyltriazine moiety, which are severely twisted each other enhance the solubility of those materials in common organic solvent. The improved solubility from this molecular design could be due to a reduced π-π stacking interaction, which gives a very uniform film morphology after spin coating of those materials. As a result, we obtained highly efficient soluble PHOLEDs combined with an evaporated blue common layer structure. The resultant red PHOLED exhibited the maximum current efficiency as well as external quantum efficiency values up to 23.7 cd/A and 19.0%.

  7. Multifunctional Fe3O4 nanoparticles for highly sensitive detection and removal of Al(iii) in aqueous solution

    Science.gov (United States)

    Zhi, Lihua; Liu, Jian; Wang, Yuan; Zhang, Wei; Wang, Baodui; Xu, Zhuguo; Yang, Zhengyin; Huo, Xing; Li, Guangming

    2013-01-01

    Fe3O4 nanoparticles (NPs) decorated with rhodamine 6G Schiff base, which exhibit high selectivity and sensitivity toward Al3+ over other common metal ions in aqueous media under a physiological pH window via a 1 : 1 binding mode, have been synthesized and characterized. The resulting conjugate 1c renders the rhodamine 6G Schiff base unit more water soluble, and the detection limit reaches 0.3 ppb in water. Moreover, 1c can detect Al3+ in a wide pH span (5.0-11.0) and enrich/remove excess Al3+ in water via an external magnetic field, which indicates that it has more potential and further practical applications for biology and toxicology. Furthermore, 1c provides good fluorescent imaging of Al3+ in living cells.Fe3O4 nanoparticles (NPs) decorated with rhodamine 6G Schiff base, which exhibit high selectivity and sensitivity toward Al3+ over other common metal ions in aqueous media under a physiological pH window via a 1 : 1 binding mode, have been synthesized and characterized. The resulting conjugate 1c renders the rhodamine 6G Schiff base unit more water soluble, and the detection limit reaches 0.3 ppb in water. Moreover, 1c can detect Al3+ in a wide pH span (5.0-11.0) and enrich/remove excess Al3+ in water via an external magnetic field, which indicates that it has more potential and further practical applications for biology and toxicology. Furthermore, 1c provides good fluorescent imaging of Al3+ in living cells. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33200k

  8. [Influence of dissolved gases on highly diluted aqueous media].

    Science.gov (United States)

    Belovolova, L V; Glushkov, M V; Vinogradov, E A

    2014-01-01

    In the experiments on redox potential measurement for a series of identical samples of purified and presettled water it was found that the response to ultraviolet irradiation varies appreciably within a few days after treatment, including stepwise changes. In a few hours after exposure, leading to a higher content of reactive oxygen species as compared with the equilibrium values, long-term changes including variations in redox potential and optical system parameters are recorded in water and diluted aqueous media. We propose a heuristic organization model of the water-gas system with an increased content of reactive oxygen species.

  9. Thermodynamic data for the speciation and solubility of Pd, Pb, Sn, Sb, Nb and Bi in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Lothenbach, B.; Ochs, M. [BMG Engineering Ltd., Zuerich-Schlieren (Switzerland); Wanner, H.; Yui, Mikazu

    1999-01-01

    This report provides thermodynamic data for predicting concentrations of palladium, lead, tin, antimony, niobium and bismuth in geologic environments, and contributes to an integration of the JNC chemical thermodynamic database, JNC-TDB (previously PNC-TDB), for the performance analysis of geological isolation system of high-level radioactive wastes. Besides treating hydrolysis in detail, this report focuses on the formation of complexes or compounds with chloride, fluoride, carbonate, nitrate, sulfate and phosphate. Other important inorganic ligands (sulfide for lead and antimony, ammonia for palladium) are also included. In this study, the specific ion interaction theory (SIT) approach is used to extrapolate thermodynamic constants to zero ionic strength at 25degC. (author)

  10. Pretreatment of Dried Distiller Grains with Solubles by Soaking in Aqueous Ammonia and Subsequent Enzymatic/Dilute Acid Hydrolysis to Produce Fermentable Sugars.

    Science.gov (United States)

    Nghiem, Nhuan P; Montanti, Justin; Kim, Tae Hyun

    2016-05-01

    Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15 % w/w NH4OH solution at a solid/liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied at two temperatures (40 and 60 °C) and four reaction times (6, 12, 24, and 48 h). Highest glucose yield of 91 % theoretical was obtained for the DDGS pretreated at 60 °C and 24 h. The solubilized hemicellulose in the liquid fraction was further hydrolyzed with dilute H2SO4 to generate fermentable monomeric sugars. The conditions of acid hydrolysis included 1 and 4 wt% acid, 60 and 120 °C, and 0.5 and 1 h. Highest yields of xylose and arabinose were obtained at 4 wt% acid, 120 °C, and 1 h. The fermentability of the hydrolysate obtained by enzymatic hydrolysis of the SAA-pretreated DDGS was demonstrated in ethanol fermentation by Saccharomyces cerevisiae. The fermentability of the hydrolysate obtained by consecutive enzymatic and dilute acid hydrolysis was demonstrated using a succinic acid-producing microorganism, strain Escherichia coli AFP184. Under the fermentation conditions, complete utilization of glucose and arabinose was observed, whereas only 47 % of xylose was used. The succinic acid yield was 0.60 g/g total sugar consumed.

  11. 一种星形水溶性聚合物的合成%Preparation and characterization of star-shaped aqueous soluble polymer

    Institute of Scientific and Technical Information of China (English)

    郑清云; 谢万知

    2014-01-01

    以羟基功能化的聚酯为引发剂,引发对二氧环己酮的开环聚合制备以聚酯为核、聚对二氧环己酮为臂的星形聚合物。星形聚合物经溴化后,引发聚乙二醇甲基丙烯酸酯的原子转移自由基聚合(ATRP)合成以聚对二氧环己酮-b-聚甲基丙烯酸聚乙二醇酯为臂的星形聚合物,并经红外测试表明聚合物已成功合成。这种星形聚合物含有聚对二氧环己酮和聚甲基丙烯酸聚乙二醇酯,是一种水溶性聚合物。%Hydroxyl Functional polyester initiators initiated the ring-opening polymerization of PDO and the star-shaped polymer with PDO arms using polyester as nuclear was produced. The bromide of star-shaped polymer, initiated the atom transfer radical polymerization(ATRP) of polyethylene glycol methacrylate and the star-shaped polymer containing the arms of ppdo-b-poly methacrylic acid polyethylene glycolester was synthesized, and the characterization of polymer structure was investigated by infrared spectroscopy and the results showed that the polymer has been successfully synthesized. The star-shaped polymer is one of aqueous soluble polymer for PPDO and PEG.

  12. Quantification of surface area and intrinsic mass transfer coefficient for ultrasound-assisted dissolution process of a sparingly soluble solid dispersed in aqueous solutions.

    Science.gov (United States)

    Durbha, Krishna Sandilya; Aravamudan, Kannan

    2012-05-01

    The efficacy of power ultrasound of 20 kHz in enhancing the volumetric mass transfer coefficient was investigated in this study. Breakage and dissolution of sparingly soluble benzoic acid dispersed in either water or 24% aqueous glycerol was monitored as a function of time and ultrasound power input. Particle size measurements were carried out at intermediate times during the experiment to estimate the mean particle size and surface area. Linear combination of lognormal distributions was found to fit the experimental particle size distribution data. The De Brouckere mean diameters (d(43)) obtained from the particle size distributions decreased with increase in the ultrasonic power level. Empirical correlations were developed for the evolution of surface area as a function of ultrasonic energy input per unit mass. The effect of ultrasound on the intrinsic mass transfer coefficient (k(c)) could be decoupled from the volumetric mass transfer coefficient (k(c)a) as the surface area was also estimated. Different approaches involving either constant or variable intrinsic mass transfer coefficients were employed when carrying out the delineation. Mass transfer rates were enhanced due to both higher ultrasound induced intrinsic convective mass transfer coefficient and additional surface area created from particle breakage. To delineate the effects of particle breakage from solid dissolution, experiments were also carried out under non-mass transfer conditions by pre-saturating the solvents with benzoic acid. Both the solid-liquid systems examined in the present study attained saturation concentration when the ultrasonic energy input per unit mass was approximately 60 kJ/kg, irrespective of the ultrasonic power level setting.

  13. High-conjugation-efficiency aqueous CdSe quantum dots.

    Science.gov (United States)

    Au, Giang H T; Shih, Wan Y; Shih, Wei-Heng

    2013-11-12

    Quantum dots (QDs) are photoluminescent nanoparticles that can be directly or indirectly coupled with a receptor such as an antibody to specifically image a target biomolecule such as an antigen. Recent studies have shown that QDs can be directly made at room temperature and in an aqueous environment (AQDs) with 3-mercaptopropionic acid (MPA) as the capping ligand without solvent and ligand exchange typically required by QDs made by the organic solvent routes (OQDs). In this study, we have synthesized CdSe AQDs and compared their conjugation efficiency and imaging efficacy with commercial carboxylated OQDs in HT29 colon cancer cells using a primary antibody-biotinylated secondary antibody-streptavidin (SA) sandwich. We showed that the best imaging condition for AQDs occurred when one AQD was bound with 3 ± 0.3 SA with a nominal SA/AQD ratio of 4 corresponding to an SA conjugation efficiency of 75 ± 7.5%. In comparison, for commercial CdSe-ZnS OQDs to achieve 2.7 ± 0.4 bound SAs per OQD for comparable imaging efficacy a nominal SA/OQD ratio of 80 was needed corresponding to an SA conjugation efficiency of 3.4 ± 0.5% for CdSe-ZnS OQDs. The more than 10 times better SA conjugation efficiency of the CdSe AQDs as compared to that of the CdSe-ZnS OQDs was attributed to more capping molecules on the AQD surface as a result of the direct aqueous synthesis. More capping molecules on the AQD surface also allowed the SA-AQD conjugate to be stable in cell culture medium for more than three days without losing their staining capability in a flowing cell culture medium. In contrast, SA-OQD conjugates aggregated in cell culture medium and in phosphate buffer saline solution over time.

  14. SOLVENT EFFECTS ON THE HYDRATION OF CYCLOHEXENE CATALYZED BY A STRONG ACID ION-EXCHANGE RESIN .1. SOLUBILITY OF CYCLOHEXENE IN AQUEOUS SULFOLANE MIXTURES

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    1992-01-01

    The solubility of cyclohexene in different water-sulfolane mixtures was measured between 313 and 413 K. The results demonstrate a sharp increase of the solubility of cyclohexene with increasing percentages of sulfolane in the solvent mixture. Without sulfolane the increase of the solubility with tem

  15. Highly sensitive visual detection of copper (II) using water-soluble azide-functionalized gold nanoparticles and silver enhancement.

    Science.gov (United States)

    Zhang, Zhen; Li, Wenqing; Zhao, Qiuling; Cheng, Ming; Xu, Li; Fang, Xiaohong

    2014-09-15

    A high-sensitive method for the visual detection of copper ions in aqueous solution is developed. The method is based on copper ion-catalyzed 'click' reaction between the water-soluble azide-functionalized gold nanoparticles (AuNPs) and alkyne-modified glass slide. The PEG linker was employed as a stabilizing component along with the terminal azide group to keep the AuNPs stably dispersed in water without the assistance of any organic solvent. In the presence of copper ions, the AuNPs are 'clicked' on the slide, and the darkness of the AuNPs in the sample spot is promoted by silver enhancement process. Only a tiny amount of sample (10 μl) is needed with the detectable concentration down to 62 pM by the commonly used flatbed scanner, which is 2-3 orders of magnitude lower than those in previous reports. The selectivity relative to other potentially interfering ions and the applicability in real samples, human serum and tap water, have also been evaluated. Our method has a good potential in point-of-use applications and environment surveys. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Design and synthesis of highly luminescent near-infrared-emitting water-soluble CdTe/CdSe/ZnS core/shell/shell quantum dots.

    Science.gov (United States)

    Zhang, Wenjin; Chen, Guanjiao; Wang, Jian; Ye, Bang-Ce; Zhong, Xinhua

    2009-10-19

    Applications of water-dispersible near-infrared (NIR)-emitting quantum dots (QDs) have been hampered by their instability and low photoluminescence (PL) efficiencies. In this paper, water-soluble highly luminescent NIR-emitting QDs were developed through constructing CdTe/CdSe/ZnS core/shell/shell nanostructure. The CdTe/CdSe type-II structure yields the QDs with NIR emission. By varying the size of CdTe cores and the thickness of the CdSe shell, the emission wavelength of the obtained nanostructure can span from 540 to 825 nm. In addition, the passivation of the ZnS shell with a substantially wide bandgap confines the excitons within the CdTe/CdSe interface and isolates them from the solution environment and consequently improves the stability of the nanostructure, especially in aqueous media. An effective shell-coating route was developed for the preparation of CdTe/CdSe core/shell nanostructures by selecting capping reagents with a strong coordinating capacity and adopting a low temperature for shell deposition. An additional ZnS shell was deposited around the outer layer of CdTe/CdSe QDs to form the core/shell/shell nanostructure through the decomposition of single molecular precursor zinc diethyldithiocarbamate in the crude CdTe/CdSe reaction solution. The water solubilization of the initially oil-soluble CdTe/CdSe/ZnS QDs was achieved through ligand replacement by 3-mercaptopropionic acid. The as-prepared water-soluble CdTe/CdSe/ZnS QDs possess PL quantum yields as high as 84% in aqueous media, which is one of the best results for the luminescent semiconductor nanocrystals.

  17. Decreased plasma soluble erythropoietin receptor in high-altitude excessive erythrocytosis and Chronic Mountain Sickness

    OpenAIRE

    Villafuerte, Francisco C.; Macarlupú, José Luis; Anza-Ramírez, Cecilia; Corrales-Melgar, Daniela; Vizcardo-Galindo, Gustavo; Corante, Noemí; León-Velarde, Fabiola

    2014-01-01

    Excessive erythrocytosis (EE) is the hallmark of chronic mountain sickness (CMS), a prevalent syndrome in high-altitude Andean populations. Although hypoxemia represents its underlying stimulus, why some individuals develop EE despite having altitude-normal blood erythropoietin (Epo) concentration is still unclear. A soluble form of the Epo receptor (sEpoR) has been identified in human blood and competes directly for Epo with its membrane counterpart (mEpoR). Thus, reduced levels of circulati...

  18. Application of a PEG precipitation method for solubility screening: a tool for developing high protein concentration formulations.

    Science.gov (United States)

    Li, Li; Kantor, Angela; Warne, Nicholas

    2013-08-01

    Previous publications demonstrated that the extrapolated solubility by polyethylene glycol (PEG) precipitation method (Middaugh et al., J Biol Chem 1979; 254:367-370; Juckes, Biochim Biophys Acta 1971; 229:535-546; Foster et al., Biochim Biophys Acta 1973; 317:505; Mahadevan and Hall, AIChE J 1990; 36:1517-1528; Stevenson and Hageman, Pharm Res 1995; 12:1671-1676) has a strong correlation to experimentally measured solubility of proteins. Here, we explored the utility of extrapolated solubility as a method to compare multiple protein drug candidates when nonideality of a highly soluble protein prohibits accurate quantitative solubility prediction. To achieve high efficiency and reduce the amount of protein required, the method is miniaturized to microwell plate format for high-throughput screening application. In this simplified version of the method, comparative solubility of proteins can be obtained without the need of concentration measurement of the supernatant following the precipitation step in the conventional method. The monoclonal antibodies with the lowest apparent solubilities determined by this method are the most difficult to be concentrated, indicating a good correlation between the prediction and empirical observations. This study also shows that the PEG precipitation method gives results for opalescence prediction that favorably compares to experimentally determined opalescence levels at high concentration. This approach may be useful in detecting proteins with potential solubility and opalescence problems prior to the time-consuming and expensive development process of high concentration formulation. © 2013 The Protein Society.

  19. SYNTHESES OF THE SOLUBLE, HIGH MOLECULAR WEIGHT AND LADDERLIKE POLYPHENYLSILSESQUIOXANE AND COPOLYMETHYLPHENYLSILSESQUIOXANES BY PREAMMINOLYSIS METHOD

    Institute of Scientific and Technical Information of China (English)

    XIE Zusho; DAI Daorong; ZHANG Rongben

    1991-01-01

    Soluble, high molecular weight (MW) and ladderlike polyphenylsilsesquioxane ( LPPSQ ) and its copolymers, ladderlike random and block copolymethylphenylsilsesquioxanes( LR-PMPSQ and LB -PMPSQ )have been prepared by preamminolysis, hydrolysis and polycondensation reactions. The preparation method can be carried out easily at the temperature below 95℃ with high yield of 95%,instead of the conventional way by using high-boiling solvent and any reaction activator or by precipitation with methanol. Three kinds of ladderlike polymers have been characterized. The MW's of the polymers reached to 106 without noticeable gelling. The scheme for synthetic route has been proposed.

  20. C-106 High-Level Waste Solids: Washing/Leaching and Solubility Versus Temperature Studies

    Energy Technology Data Exchange (ETDEWEB)

    GJ Lumetta; DJ Bates; PK Berry; JP Bramson; LP Darnell; OT Farmer III; LR Greenwood; FV Hoopes; RC Lettau; GF Piepel; CZ Soderquist; MJ Steele; RT Steele; MW Urie; JJ Wagner

    2000-01-26

    This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing and caustic leaching on the composition of the Hanford tank C-106 high-level waste (HLW) solids. The objective of this work was to determine the composition of the C-106 solids remaining after washing with 0.01M NaOH or leaching with 3M NaOH. Another objective of this test was to determine the solubility of various C-106 components as a function of temperature. The work was conducted according to test plan BNFL-TP-29953-8,Rev. 0, Determination of the Solubility of HLW Sludge Solids. The test went according to plan, with only minor deviations from the test plan. The deviations from the test plan are discussed in the experimental section.

  1. The application of water-soluble ruthenium catalysts for the hydrogenation of the dichloromethane soluble fraction of fast pyrolysis oil and related model compounds in a two phase aqueous-organic system

    NARCIS (Netherlands)

    Mahfud, F.H.; Bussemaker, S.; Kooi, B.J.; ten Brink, Gert; Heeres, H.J.

    2007-01-01

    The hydrogenation of a dichloromethane soluble fraction of flash pyrolysis oil (bio-oil, BO), obtained by treatment of BO with a water–dichloromethane solvent mixture, was investigated using a water-soluble homogeneous ruthenium catalyst (RuCl3·3H2O/tris(m-sulfonatophenyl)phosphine, TPPTS). The

  2. Pure Phase Solubility Limits: LANL

    Energy Technology Data Exchange (ETDEWEB)

    C. Stockman

    2001-01-26

    The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO{sub 2} partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility

  3. Prediction and correlation of high-pressure gas solubility in polymers with simplified PC-SAFT

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2005-01-01

    Using simplified PC-SAFT we have modeled gas solubilities at high temperatures and pressures for the gases methane and carbon dioxide in each of the three polymers high-density polyethylene (HDPE), nylon polyamide-11 (PA-11), and poly(vinylidene fluoride) (PVDF). In general the results...... are satisfactory, using in most cases a single, temperature-independent value of the binary interaction parameter. In the cases of methane in HDPE and PVDF, a temperature-dependent binary interaction parameter was required. New pure component polymer parameters for PA-11 and PVDF were obtained using a recently...

  4. High-throughput method for optimum solubility screening for homogeneity and crystallization of proteins

    Science.gov (United States)

    Kim, Sung-Hou [Moraga, CA; Kim, Rosalind [Moraga, CA; Jancarik, Jamila [Walnut Creek, CA

    2012-01-31

    An optimum solubility screen in which a panel of buffers and many additives are provided in order to obtain the most homogeneous and monodisperse protein condition for protein crystallization. The present methods are useful for proteins that aggregate and cannot be concentrated prior to setting up crystallization screens. A high-throughput method using the hanging-drop method and vapor diffusion equilibrium and a panel of twenty-four buffers is further provided. Using the present methods, 14 poorly behaving proteins have been screened, resulting in 11 of the proteins having highly improved dynamic light scattering results allowing concentration of the proteins, and 9 were crystallized.

  5. Hydrate-melt electrolytes for high-energy-density aqueous batteries

    Science.gov (United States)

    Yamada, Yuki; Usui, Kenji; Sodeyama, Keitaro; Ko, Seongjae; Tateyama, Yoshitaka; Yamada, Atsuo

    2016-10-01

    Aqueous Li-ion batteries are attracting increasing attention because they are potentially low in cost, safe and environmentally friendly. However, their low energy density (commercial Li4Ti5O12 negative electrode with a low reaction potential (1.55 V versus Li+/Li) and a high capacity (175 mAh g-1). The resultant aqueous Li-ion batteries with high energy density (>130 Wh kg-1) and high voltage (˜2.3-3.1 V) represent significant progress towards performance comparable to that of commercial non-aqueous batteries (with energy densities of ˜150-400 Wh kg-1 and voltages of ˜2.4-3.8 V).

  6. Optimizing conditions for production of high levels of soluble recombinant human growth hormone using Taguchi method.

    Science.gov (United States)

    Savari, Marzieh; Zarkesh Esfahani, Sayyed Hamid; Edalati, Masoud; Biria, Davoud

    2015-10-01

    Human growth hormone (hGH) is synthesized and stored by somatotroph cells of the anterior pituitary gland and can effect on body metabolism. This protein can be used to treat hGH deficiency, Prader-Willi syndrome and Turner syndrome. The limitations in current technology for soluble recombinant protein production, such as inclusion body formation, decrease its usage for therapeutic purposes. To achieve high levels of soluble form of recombinant human growth hormone (rhGH) we used suitable host strain, appropriate induction temperature, induction time and culture media composition. For this purpose, 32 experiments were designed using Taguchi method and the levels of produced proteins in all 32 experiments were evaluated primarily by ELISA and dot blotting and finally the purified rhGH protein products assessed by SDS-PAGE and Western blotting techniques. Our results indicate that media, bacterial strains, temperature and induction time have significant effects on the production of rhGH. The low cultivation temperature of 25°C, TB media (with 3% ethanol and 0.6M glycerol), Origami strain and a 10-h induction time increased the solubility of human growth hormone.

  7. Prediction and experimental determination of the solubility of exotic scales at high temperatures - Zinc sulfide

    DEFF Research Database (Denmark)

    Carolina Figueroa Murcia, Diana; Fosbøl, Philip Loldrup; Thomsen, Kaj

    2016-01-01

    The presence of "exotic" scale such as Zinc Sulfide (ZnS), Lead Sulfide (PbS) and Iron Sulfide (FeS) in HP/HT reservoirs has been identified. "Exotic" scale materials come as a new challenge in HP/HT reservoirs. This has led to the development of more advanced tools to predict their behavior...... at extreme conditions. The aim of this work is to include ZnS into the group of scale materials that can be modeled with the Extended UNIQUAC model. Solubility data for ZnS are scarce in the open literature. In order to improve the available data, we study the experimental behavior of ZnS solubility at high...... temperatures. The determination of the solubility of ZnS is carried out at temperatures up to 250°C. Zinc sulfide (99.99%) and ultra-pure water are placed in a vial in a reduced oxygen atmosphere. The sample is placed in a controlled bath and stirred until equilibrium is attained. The suspension is filtered...

  8. The search for reliable aqueous solubility (Sw) and octanol-water partition coefficient (Kow) data for hydrophobic organic compounds; DDT and DDE as a case study

    Science.gov (United States)

    Pontolillo, James; Eganhouse, R.P.

    2001-01-01

    The accurate determination of an organic contaminant?s physico-chemical properties is essential for predicting its environmental impact and fate. Approximately 700 publications (1944?2001) were reviewed and all known aqueous solubilities (Sw) and octanol-water partition coefficients (Kow) for the organochlorine pesticide, DDT, and its persistent metabolite, DDE were compiled and examined. Two problems are evident with the available database: 1) egregious errors in reporting data and references, and 2) poor data quality and/or inadequate documentation of procedures. The published literature (particularly the collative literature such as compilation articles and handbooks) is characterized by a preponderance of unnecessary data duplication. Numerous data and citation errors are also present in the literature. The percentage of original Sw and Kow data in compilations has decreased with time, and in the most recent publications (1994?97) it composes only 6?26 percent of the reported data. The variability of original DDT/DDE Sw and Kow data spans 2?4 orders of magnitude, and there is little indication that the uncertainty in these properties has declined over the last 5 decades. A criteria-based evaluation of DDT/DDE Sw and Kow data sources shows that 95?100 percent of the database literature is of poor or unevaluatable quality. The accuracy and reliability of the vast majority of the data are unknown due to inadequate documentation of the methods of determination used by the authors. [For example, estimates of precision have been reported for only 20 percent of experimental Sw data and 10 percent of experimental Kow data.] Computational methods for estimating these parameters have been increasingly substituted for direct or indirect experimental determination despite the fact that the data used for model development and validation may be of unknown reliability. Because of the prevalence of errors, the lack of methodological documentation, and unsatisfactory data

  9. Analysis of comparison between the theoretical and experimental solubilities of the ThO{sub 2} and CeO{sub 2} in different aqueous media; Analisis de comparacion entre las solubilidades experimentales y teoricas del ThO{sub 2} y CeO{sub 2} en diferentes medios acuosos

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, N.; Cobos, J.; Iglesias, E.; Palomo, C.; Nieto, J.; Cobo, J. M.; Serrano, L.; Duran, S.; Quinones, J.

    2012-07-01

    The present work shows the effect of the complexity of the surrounding aqueous medium that will surround the nuclear fuel stored in the solubility of the and Ce. In the case of Th, this influence is clearly accused, and the difference between the experimental and the theoretical solubility of parent company pure phase, is due to the formation of actinide-hidroxo-carbonate complex.

  10. Structure-Guided Redesign Increases the Propensity of HIV Env To Generate Highly Stable Soluble Trimers

    Science.gov (United States)

    Guenaga, Javier; Dubrovskaya, Viktoriya; de Val, Natalia; Sharma, Shailendra K.; Carrette, Barbara; Ward, Andrew B.

    2015-01-01

    ABSTRACT Due to high viral diversity, an effective HIV-1 vaccine will likely require Envs derived from multiple subtypes to generate broadly neutralizing antibodies (bNAbs). Soluble Env mimics, like the native flexibly linked (NFL) and SOSIP trimers, derived from the subtype A BG505 Env, form homogeneous, stable native-like trimers. However, other Env sequences, such as JRFL and 16055 from subtypes B and C, do so to a lesser degree. The high-resolution BG505 SOSIP crystal structures permit the identification and redesign of Env elements involved in trimer stability. Here, we identified structure trimer-derived (TD) residues that increased the propensity of the subtype B JRFL and subtype C 16055 Env sequences to form well-ordered, homogenous, and highly stable soluble trimers. The generation of these spike mimics no longer required antibody-based selection, positive or negative. Using the redesigned subtype B and C trimer representatives as respective foundations, we further stabilized the NFL TD trimers by engineering an intraprotomer disulfide linkage in the prebridging sheet, I201C-A433C (CC), that locks the gp120 in the receptor nontriggered state. We demonstrated that this disulfide pair prevented CD4 induced-conformational rearrangements in NFL trimers derived from the prototypic subtype A, B, and C representatives. Coupling the TD-based design with the engineered disulfide linkage, CC, increased the propensity of Env to form soluble highly stable spike mimics that are resistant to CD4-induced changes. These advances will allow testing of the hypothesis that such stabilized immunogens will more efficiently elicit neutralizing antibodies in small-animal models and primates. IMPORTANCE HIV-1 displays unprecedented global diversity circulating in the human population. Since the envelope glycoprotein (Env) is the target of neutralizing antibodies, Env-based vaccine candidates that address such diversity are needed. Soluble well-ordered Env mimics, typified by NFL

  11. Cultivation Methods for Tomato (Lycopersicon esculentum Mill.) with High Soluble Solids Content Using the Vertically Split Root System

    National Research Council Canada - National Science Library

    HAYASHI, Hiroyuki; TOYOFUKU, Kyoko; TAGUCHI, Takiko; OGAWA, Atsushi

    2014-01-01

    For the cultivation of tomatoes with high soluble solids content, the root system was split vertically and irrigation to the upper part of the root system was stopped to create split vertically (SR treatment...

  12. Effect of Bombay high crude oil and its water-soluble fraction on growth and metabolism of diatom Thalassiosira sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Parab, S.R.; Pandit, R.A.; Kadam, A.N.; Indap, M.M.

    Effect of Bombay high crude oil (BHC) and its water-soluble fraction (WSF) on growth and metabolism of the phytoplankton, Thalassiosira sp. was assessed. The study revealed the signs of acute toxicity at higher concentrations of crude oil (0...

  13. Efficient Route to Highly Water-Soluble Aromatic Cyclic Hydroxamic Acid Ligands

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, Michael; Raymond, Kenneth N.

    2008-02-06

    2-Hydroxyisoquinolin-1-one (1,2-HOIQO) is a new member of the important class of aromatic cyclic hydroxamic acid ligands which are widely used in metal sequestering applications and metal chelating therapy. The first general approach for the introduction of substituents at the aromatic ring of the chelating moiety is presented. As a useful derivative, the highly water-soluble sulfonic acid has been synthesized by an efficient route that allows general access to 1,2-HOQIO 3-carboxlic acid amides, which are the most relevant for applications.

  14. Up-Conversion Luminescence of a High Soluble Zinc Phthalocyanine-Epoxy Derivative

    Institute of Scientific and Technical Information of China (English)

    沈悦; 夏义本; 陈精纬; 顾峰; 焦凤华; 张建成

    2004-01-01

    Synthesis and photoelectric properties of a high soluble zinc phthalocyanine-epoxy derivative are investigated.The derivative can be solubilized in convenient solvents, such as CH3OH, CH3CH2OH and H2O. The fluorescence and UV-visible analyses indicate that the ZnPc-epoxy derivative still maintains the plane structure which comes from Zn(4,4',4",4″′-ta)Pc and the derivative has obvious up-conversion luminescence in room temperature. The up-conversion luminescence can be explained by the selection rule depending on the two-photon absorption.

  15. Aqueous synthesis of high bright Ag{sub 2}Se−ZnSe quantum dots with tunable near-infrared emission

    Energy Technology Data Exchange (ETDEWEB)

    Che, Dongchen; Ding, Di [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201602 (China); Wang, Hongzhi, E-mail: wanghz@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201602 (China); Zhang, Qinghong [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201602 (China); Li, Yaogang, E-mail: yaogang_li@dhu.edu.cn [Engineering Research Center of Advanced Glass Manufacturing Technology, Ministry of Education, Donghua University, Shanghai 201602 (China)

    2016-09-05

    Efficient aqueous synthetic methods for near-infrared quantum dots as bioimaging agents are urgently required. In this work, a simple and fast synthesis of highly luminescent, near-infrared Ag{sub 2}Se quantum dots (QDs) in aqueous media is reported. The method avoids high temperature, pressure and organic solvents to directly generate water-dispersible Ag{sub 2}Se QDs. The photoluminescence emission of Ag{sub 2}Se QDs ranges from 835 to 940 nm by different Ag:Se molar ratio. Using the ZnSe as a shell, the quantum yield reaches up to 42%. The Ag{sub 2}Se−ZnSe QDs with high quantum yield, near-infrared and low cytotoxic could be used as good cell labels, showing great potential applications in bio-imaging. - Highlights: • Ag{sub 2}Se−ZnSe nanocrystals are prepared directly in aqueous media at low temperature. • Ag{sub 2}Se−ZnSe nanocrystals show excellent water solubility and colloidal stability. • Ag{sub 2}Se nanocrystals exhibit tunable near-infrared emission with ultrasmall size. • Ag{sub 2}Se−ZnSe nanocrystals show high quantum yield with low cytotoxicity. • Ag{sub 2}Se−ZnSe nanocrystals are stable over a month at room temperature in the air.

  16. Organic acids as cloud condensation nuclei: Laboratory studies of highly soluble and insoluble species

    Directory of Open Access Journals (Sweden)

    P. Pradeep Kumar

    2003-01-01

    Full Text Available The ability of sub-micron-sized organic acid particles to act as cloud condensation nuclei (CCN has been examined at room temperature using a newly constructed continuous-flow, thermal-gradient diffusion chamber (TGDC. The organic acids studied were: oxalic, malonic, glutaric, oleic and stearic. The CCN properties of the highly soluble acids - oxalic, malonic and glutaric - match very closely Köhler theory predictions which assume full dissolution of the dry particle and a surface tension of the growing droplet equal to that of water. In particular, for supersaturations between 0.3 and 0.6, agreement between the dry particle diameter which gives 50% activation and that calculated from Köhler theory is to within 3nm on average. In the course of the experiments, considerable instability of glutaric acid particles was observed as a function of time and there is evidence that they fragment to some degree to smaller particles. Stearic acid and oleic acid, which are both highly insoluble in water, did not activate at supersaturations of 0.6% with dry diameters up to 140nm. Finally, to validate the performance of the TGDC, we present results for the activation of ammonium sulfate particles that demonstrate good agreement with Köhler theory if solution non-ideality is considered. Our findings support earlier studies in the literature that showed highly soluble organics to be CCN active but insoluble species to be largely inactive.

  17. "Switchable water": aqueous solutions of switchable ionic strength.

    Science.gov (United States)

    Mercer, Sean M; Jessop, Philip G

    2010-04-26

    "Salting out" is a standard method for separating water-soluble organic compounds from water. In this method, adding a large amount of salt to the aqueous solution forces the organic compound out of the aqueous phase. However, the method can not be considered sustainable because it creates highly salty water. A greener alternative would be a method that allows reversible salting out. Herein, we describe aqueous solutions of switchable ionic strength. Aqueous solutions of a diamine in water have essentially zero ionic strength but are converted by CO(2) into solutions of high ionic strength. The change is reversible. Application to the reversible salting out of THF from water is described.

  18. Recognition of caffeine in aqueous solutions

    NARCIS (Netherlands)

    Fiammengo, R.; Crego Calama, Mercedes; Timmerman, P.; Reinhoudt, David

    2003-01-01

    Binding of caffeine in aqueous solutions has been achieved for the first time by using water-soluble, tetracationic peptide-porphyrin conjugates Zn-1 as the receptor molecules. The association constant for caffeine with receptor Zn-1 is in some cases as high as 6000 M-1, only 5-6 times lower than

  19. CdS quantum dots as fluorescence probes for the sensitive and selective detection of highly reactive HSe- ions in aqueous solution.

    Science.gov (United States)

    Wu, Chuan-Liu; Zhao, Yi-Bing

    2007-06-01

    Water-soluble cadmium sulfide (CdS) quantum dots (QDs) capped by mercaptoacetic acid were synthesized by aqueous-phase arrested precipitation, and characterized by transmission electron microscopy, spectrofluorometry, and UV-Vis spectrophotometry. The prepared luminescent water-soluble CdS QDs were evaluated as fluorescence probes for the detection of highly reactive hydrogen selenide ions (HSe(-) ions). The quenching of the fluorescence emission of CdS QDs with the addition of HSe(-) ions is due to the elimination of the S(2-) vacancies which are luminescence centers. Quantitative analysis based on chemical interaction between HSe(-) ions and the surface of CdS QDs is very simple, easy to develop, and has demonstrated very high sensitivity and selectivity features. The effect of foreign ions (common anions and biologically relevant cations) on the fluorescence of the CdS QDs was examined to evaluate the selectivity. Only Cu(2+) and S(2-) ions exhibit significant effects on the fluorescence of CdS QDs. With the developed method, we are able to determine the concentration of HSe(-) ions in the range from 0.10 to 4.80 micromol L(-1), and the limit of detection is 0.087 micromol L(-1). The proposed method was successfully applied to monitor the obtained HSe(-) ions from the reaction of glutathione with selenite. To the best of our knowledge, this is the first report on fluorescence analysis of HSe(-) ions in aqueous solution.

  20. Non-aqueous electrolyte for high voltage rechargeable magnesium batteries

    Science.gov (United States)

    Doe, Robert Ellis; Lane, George Hamilton; Jilek, Robert E; Hwang, Jaehee

    2015-02-10

    An electrolyte for use in electrochemical cells is provided. The properties of the electrolyte include high conductivity, high Coulombic efficiency, and an electrochemical window that can exceed 3.5 V vs. Mg/Mg.sup.+2. The use of the electrolyte promotes the electrochemical deposition and dissolution of Mg without the use of any Grignard reagents, other organometallic materials, tetraphenyl borate, or tetrachloroaluminate derived anions. Other Mg-containing electrolyte systems that are expected to be suitable for use in secondary batteries are also described.

  1. Radiation grafting of various water-soluble monomers on ultra-high molecular weight polyethylene powder:. Part I. Grafting conditions and grafting yield

    Science.gov (United States)

    Aydinli, Bahattin; Tinçer, Teoman

    2001-02-01

    Monomers of some water-soluble polymers; acrylic acid, methacrylic acid, acrylamide, N, N -dimethyl acrylamide and 1-vinyl-2 pyrrolidone, were grafted on ultra-high molecular weight polyethylene (UHMWPE) powders by a direct grafting method in an aqueous medium in air. Inhibition of homopolymerisation was achieved by adding various concentrations of Fe 2+ or Cu 2+ ions. It was found that the degree of grafting increases linearly with dose till a gelation state is reached, and varies between 40 and 12% depending on the monomer. Four million molecular weight UHMWPE gave a higher per cent grafting than a 6 million counterpart for the monomers used, with the exception of acrylic acid monomer grafting.

  2. Radiation grafting of various water-soluble monomers on ultra-high molecular weight polyethylene powder: Part I. Grafting conditions and grafting yield

    Energy Technology Data Exchange (ETDEWEB)

    Aydinli, Bahattin; Tincer, Teoman E-mail: teotin@metu.edu.tr

    2001-02-01

    Monomers of some water-soluble polymers; acrylic acid, methacrylic acid, acrylamide, N, N-dimethyl acrylamide and 1-vinyl-2 pyrrolidone, were grafted on ultra-high molecular weight polyethylene (UHMWPE) powders by a direct grafting method in an aqueous medium in air. Inhibition of homopolymerisation was achieved by adding various concentrations of Fe{sup 2+} or Cu{sup 2+} ions. It was found that the degree of grafting increases linearly with dose till a gelation state is reached, and varies between 40 and 12% depending on the monomer. Four million molecular weight UHMWPE gave a higher per cent grafting than a 6 million counterpart for the monomers used, with the exception of acrylic acid monomer grafting. (author)

  3. High-performance aqueous asymmetric electrochemical capacitor based on graphene oxide/cobalt(II)-tetrapyrazinoporphyrazine hybrids

    CSIR Research Space (South Africa)

    Lekitima, JN

    2013-01-01

    Full Text Available equivalent series resistance clearly indicate that this new material has great potential for the development of low-cost and ‘green’ aqueous AECs that operate at high energy and power densities. Interestingly, the energy density of the GO/CoTPyzPz//GOCB based...

  4. Aqueous-core PEG-coated PLA nanocapsules for an efficient entrapment of water soluble anticancer drugs and a smart therapeutic response.

    Science.gov (United States)

    Cosco, Donato; Paolino, Donatella; De Angelis, Francesco; Cilurzo, Felisa; Celia, Christian; Di Marzio, Luisa; Russo, Diego; Tsapis, Nicolas; Fattal, Elias; Fresta, Massimo

    2015-01-01

    Novel PEGylated PLA nanocapsules (PEG-AcPLA nanocapsules), loading high percentage of water soluble drugs have been formulated by using multiple emulsion technique without using conventional stabilizers. In particular, sodium deoxycholate hydrate has been used to obtain nanocapsules having a mean diameter of about 200 nm and a polydispersity index of ∼ 0.1. Gemcitabine hydrochloride (GEM) was used as a model of hydrophilic drug. GEM-loaded PEG-AcPLA nanocapsules demonstrated a high encapsulation efficacy and the drug-release followed a zero-order kinetic. MTT-assay evidenced an increased antitumor effect of GEM-loaded PEG-AcPLA nanocapsules compared to the free drug on different cancer cell lines and confocal laser scanning microscopy showed a significant improvement of cell interaction at 6h of incubation. In vivo anticancer activity of GEM-loaded PEG-AcPLA nanocapsules using two xenograft murine models of human solid tumors further supported the efficacy of this nano-drug, thus providing preliminary results about the potential clinical application of this innovative nanotherapeutic.

  5. In Vivo Biodistribution and Toxicity of Highly Soluble PEG-Coated Boron Nitride in Mice

    Science.gov (United States)

    Liu, Bo; Qi, Wei; Tian, Longlong; Li, Zhan; Miao, Guoying; An, Wenzhen; Liu, Dan; Lin, Jing; Zhang, Xiaoyong; Wu, Wangsuo

    2015-12-01

    The boron nitride (BN) nanoparticles, as the structural analogues of graphene, are the potential biomedicine materials because of the excellent biocompatibility, but their solubility and biosafety are the biggest obstacle for the clinic application. Here, we first synthesized the highly soluble BN nanoparticles coated by PEG (BN-PEG) with smaller size (~10 nm), then studied their biodistribution in vivo through radioisotope (Tc99mO4 -) labeling, and the results showed that BN-PEG nanoparticles mainly accumulated in the liver, lung, and spleen with the less uptake by the brain. Moreover, the pathological changes induced by BN-PEG could be significantly observed in the sections of the liver, lung, spleen, and heart, which can be also supported by the test of biochemical indexes in serum. More importantly, we first observed the biodistribution of BN-PEG in the heart tissues with high toxicity, which would give a warning about the cardiovascular disease, and provide some opportunities for the drug delivery and treatment.

  6. Influence of polymethacrylates and compritol on release profile of a highly water soluble drug metformin hydrochloride

    Directory of Open Access Journals (Sweden)

    Sunita Dahiya

    2015-01-01

    Full Text Available Aims: The present investigation studied effect of polymethacrylates Eudragit RSPO, Eudragit RLPO and compritol 888 ATO on release profile of highly water soluble drug metformin hydrochloride (MET. Materials and Methods: The solid dispersions were prepared using drug:polymer ratios 1:1 and 1:5 by coevaporation and coprecipitation techniques. Solid dispersions were characterized by infrared Spectroscopy (IR, differential scanning calorimetry (DSC, X-ray diffractometry (XRD as well as content uniformity, in vitro dissolution studies in 0.1 N HCl pH 1.2, phosphate buffer pH 6.8. Results and Discussion: Results of the studies suggested that there were progressive disappearance or changes of prominent peaks in IR, X-ray diffraction and thermotropic drug signals in coevaporates and coprecipitates with increased amount of polymers. Moreover, the in vitro release of highly water soluble MET could be extended at higher drug:polymer ratios. Conclusion: It was summarized that Eudragit RLPO had greater capacity of drug release than Eudragit RSPO and Comproitol 888 and its coevaporates in 1:5 drug:polymer ratio (F11 displayed extended drug release with comparatively higher dissolution rates (92.15 % drug release at 12 hour following near Zero order kinetics (r² =0.9822.

  7. An aqueous thermodynamic model for the Pb 2+-Na +-K +-Ca 2+-Mg 2+-H +-Cl --SO 42--H 2O system to high concentration: application to WIPP brines

    Science.gov (United States)

    Felmy, Andrew R.; Onishi, Lisa M.; Foster, Nancy S.; Rustad, James R.; Rai, Dhanpat; Mason, Marvin J.

    2000-11-01

    The development of an aqueous thermodynamic model for the Pb 2+-Na +-K +-Ca 2+-Mg 2+-Cl --SO 42--H 2O system is presented, which is valid to high ionic strengths at 25°C. The model is based on the equations of Pitzer and has been parameterized from existing solubility, osmotic, electromotive force (emf), and spectroscopic data. To accurately represent the aqueous thermodynamics of Pb 2+ in concentrated chloride containing solutions required the inclusion of four Pb chloride species (i.e., PbCl +, PbCl 2(aq), PbCl 3-, and PbCl 42-) along with the necessary Pitzer ion interaction parameters for these species with the major electrolyte ions. The reliability of the final equilibrium model is tested against experimental solubility data on PbCl 2(c) and PbSO 4(c) in high ionic strength Waste Isolation Pilot Plant (WIPP) brines obtained as part of this study. On an overall basis the model accurately predicted the aqueous speciation, based on comparisons with our UV-Vis spectroscopy measurements, as well as the observed solubility. The model also proved satisfactory in predicting the observed solid phase assemblages, with the possible exception of those found in solutions high in KCl.

  8. Self-double-emulsifying drug delivery system (SDEDDS): a new way for oral delivery of drugs with high solubility and low permeability.

    Science.gov (United States)

    Qi, Xiaole; Wang, Lishuang; Zhu, Jiabi; Hu, Zhenyi; Zhang, Jie

    2011-05-16

    Water-in-oil-in-water (w/o/w) double emulsions are potential for enhancing oral bioavailability of drugs with high solubility and low permeability, but their industrial application is limited due to the instability. Herein, we developed a novel formulation, self-double-emulsifying drug delivery systems (SDEDDS) by formulating mixtures of hydrophilic surfactants and water-in-oil (w/o) emulsions, which were easier to be stable through formulations optimization. SDEDDS can spontaneously emulsify to water-in-oil-in-water (w/o/w) double emulsions in the mixed aqueous gastrointestinal environment, with drugs encapsulated in the internal water phase of the double emulsions. We employed SDEDDS to improve the oral absorption of pidotimod, a peptide-like drug with high solubility and low permeability. The optimized pidotimod-SDEDDS were found to be stable up to 6 months under 25°C. Plasma concentration-time profiles from pharmacokinetic studies in rats dosed with SDEDDS showed 2.56-fold (p<0.05) increased absorption of pidotimod, compared to the pidotimod solution. Histopathologic studies confirmed that SDEDDS exerted absorption promoting effect without serious local damages. These studies demonstrate that SDEDDS may be a promising strategy for peroral delivery of peptide and peptidomimetic drugs.

  9. Highly sensitive and selective detection of phosphate using novel highly photoluminescent water-soluble Mn-doped ZnTe/ZnSe quantum dots.

    Science.gov (United States)

    Song, Yu; Li, Yang; Liu, Yunling; Su, Xingguang; Ma, Qiang

    2015-11-01

    Herein, the facile method with high selectivity for phosphate ion (Pi) sensing using novel Type-II core/shell Mn: ZnTe/ZnSe quantum dots (QDs) was reported. This was the first time that Mn: ZnTe/ZnSe QDs with highlighted optical properties were used for sensing. The water-soluble Mn: ZnTe/ZnSe QDs with a high quantum yield of 7% were synthesized by aqueous synthetic method. Compared with traditional ZnSe QDs or Mn: ZnSe QDs, the smaller effective band gap, longer wavelength and lower ionization potential (high valence band edge) for effective hole localization made Type-II core/shell Mn: ZnTe/ZnSe QDs to be stable and had high photoluminescence (PL). Only Mg(2+) was found to be able to enhance Mn: ZnTe/ZnSe QDs PL selectively. The mechanism of fluorescence enhancement was attributed to the passivated surface nonradiative relaxation centers of Mn: ZnTe/ZnSe QDs. In the presence of Pi anion, the PL intensity got quenched due to the aggregation species of QDs via electrostatic attraction between Pi and Mg(2+) on the surface of Mn: ZnTe/ZnSe QDs. Therefore, the quenching effect can be used to detect Pi selectively. The PL was observed to be linearly proportional to the Pi analyte concentration in the range from 0.67 to 50.0 μmol/L, with a detection limit of 0.2μ mol/L (S/N=3). The novel "on-off" fluorescence nanosensor for Pi detection was sensitive and convenient in the real analysis application. The reported analytical method of Mn: ZnTe/ZnSe QDs is highly sensitive and selective, which can corroborate the extension of its usages in chemo/ biosensing and bioimaging. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Catalysis with Soluble Hybrids of Highly Branched Macromolecules with Palladium Nanoparticles in a Continuously Operated Membrane Reactor

    OpenAIRE

    2003-01-01

    The continuous recovery and recycling of soluble metal nanoparticles by means of ultrafiltration is described, employing hybrids of palladium nanoparticles with highly branched amphiphilic polyglycerol as a catalyst for cyclohexene hydrogenation as a model reaction. In a continuously operated membrane reactor a productivity of 29000 TO over 30 exchanged reactor volumes was observed for nanoparticles of 2.2 nm size, with a maximum rate of 1200 TO h-1. Catalysis by soluble metal complexes can b...

  11. High-resolution patterning electronic polymers using dopant induced solubility control (Presentation Recording)

    Science.gov (United States)

    Moule, Adam J.; Jacobs, Ian E.; Li, Jun; Burg, Stephanie L.; Bilsky, David J.; Rotondo, Brandon T.; Stroeve, Pieter

    2015-08-01

    Organic electronics promise to provide flexible, large-area circuitry such as photovoltaics, displays, and light emitting diodes that can be fabricated inexpensively from solutions. A major obstacle to this vision is that most conjugated organic materials are miscible, making solution-based fabrication of multilayer or micro- to nanoscale patterned films problematic. Here we demonstrate that the solubility of prototypical conductive polymer poly(3-hexylthiophene) (P3HT) can be reversibly "switched off" using high electron affinity molecular dopants, then later recovered with light or a suitable dedoping solution. Using this technique, we are able to stack mutually soluble materials and laterally pattern polymer films using evaporation of dopants through a shadow mask or with light, achieving sub-micrometer, optically limited feature sizes. After forming these structures, the films can be dedoped without disrupting the patterned features; dedoped films have identical optical characteristics, charge carrier mobilities, and NMR spectra as as-cast P3HT films. This method greatly simplifies solution-based device fabrication, is easily adaptable to current manufacturing workflows, and is potentially generalizable to other classes of materials.

  12. 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.

  13. Highly water-soluble platinum(II) complexes as GLUT substrates for targeted therapy: improved anticancer efficacy and transporter-mediated cytotoxic properties.

    Science.gov (United States)

    Liu, Pengxing; Lu, Yanhui; Gao, Xiangqian; Liu, Ran; Zhang-Negrerie, Daisy; Shi, Ying; Wang, Yiqiang; Wang, Songqing; Gao, Qingzhi

    2013-03-25

    Glucose-conjugated malonato-platinum(II) complexes are designed and synthesized to target tumor-specific active transporters, namely, glucose transporters (GLUTs); the complexes exhibit much higher aqueous solubility by 150 times, improved potency in cytotoxicities by 10 times, and increased therapeutic index by over 30 fold compared to the newest generation of clinical drugs oxaliplatin.

  14. Designing a highly active soluble PQQ-glucose dehydrogenase for efficient glucose biosensors and biofuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Durand, Fabien [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France); Stines-Chaumeil, Claire [Universite de Bordeaux, CNRS, Institut de Biochimie et de Genetique Cellulaires, 1 rue Camille Saint Saens, 33077 Bordeaux Cedex (France); Flexer, Victoria [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France); Andre, Isabelle [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); CNRS, UMR5504, F-31400 Toulouse (France); INRA, UMR 792 Ingenierie des Systemes Biologiques et des Procedes, F-31400 Toulouse (France); Mano, Nicolas, E-mail: mano@crpp-bordeaux.cnrs.fr [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France)

    2010-11-26

    Research highlights: {yields} A new mutant of PQQ-GDH designed for glucose biosensors application. {yields} First mutant of PQQ-GDH with higher activity for D-glucose than the Wild type. {yields} Position N428 is a key point to increase the enzyme activity. {yields} Molecular modeling shows that the N428 C mutant displays a better interaction for PQQ than the WT. -- Abstract: We report for the first time a soluble PQQ-glucose dehydrogenase that is twice more active than the wild type for glucose oxidation and was obtained by combining site directed mutagenesis, modelling and steady-state kinetics. The observed enhancement is attributed to a better interaction between the cofactor and the enzyme leading to a better electron transfer. Electrochemical experiments also demonstrate the superiority of the new mutant for glucose oxidation and make it a promising enzyme for the development of high-performance glucose biosensors and biofuel cells.

  15. A highly soluble matrix metalloproteinase-9 inhibitor for potential treatment of dry eye syndrome.

    Science.gov (United States)

    Mori, Mattia; De Lorenzo, Emanuele; Torre, Eugenio; Fragai, Marco; Nativi, Cristina; Luchinat, Claudio; Arcangeli, Annarosa

    2012-11-01

    Dry eye syndrome (DES) or keratoconjunctivitis sicca is an eye disease caused by the chronic lack of lubrication and moisture of the eye. The pathogenesis of DES involves the over-expression and over-activity of corneal Matrix Metalloproteinase 9 (MMP-9). We propose herein a new, non-symptomatic approach for the treatment of DES based on the inhibition of MMP-9 by a new highly soluble molecule, designed as PES_103 that has been shown to inhibit MMP-9 both in vitro and in vivo. The efficacy of PES_103 in vivo and the potential benefits of this treatment in restoring tear production were studied in this work using an animal model of reduced lacrimation. PES_103 did not show any significant corneal toxicity. © 2012 The Authors Basic & Clinical Pharmacology & Toxicology © 2012 Nordic Pharmacological Society.

  16. A novel strategy to produce highly stable and transparent aqueous 'nanosolutions' of water-insoluble drug molecules

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jiexin; Zhang Zhibing; Le Yuan; Chen Jianfeng [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Zhao Hong, E-mail: chenjf@mail.buct.edu.cn [Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-07-29

    A surprisingly large proportion of new drug candidates emerging from drug discovery programmes are water-insoluble and, as a result, have poor oral bioavailability. To overcome insolubility, the drug particles are usually dispersed in a medium during product formation, but large particles that are formed may affect product performance and safety. Many techniques have been used to produce nanodispersions-dispersions with nanometre-scale dimensions-that have properties similar to solutions. However, making nanodispersions requires complex processing, and it is difficult to achieve stability over long periods. In this paper, we report a generic method for preparing drug nanoparticles with a combination of antisolvent precipitation in the presence of water-soluble matrices and spray-drying. The spray-dried powder composites (solid dispersion) are microspherical, highly stable and thus form transparent nanodispersions or so-called 'nanosolutions' of water-insoluble drug when simply added to water. Aqueous nanodispersions of silybin (a kind of water-insoluble drug for liver protection) with an average size of 25 nm produced with this approach display a 10 times faster dissolution rate than that of raw drug. This has great potential to offer a novel solution for innovative drugs of the future.

  17. Aqueous solubility study of salts of benzylamine derivatives and p-substituted benzoic acid derivatives using X-ray crystallographic analysis

    DEFF Research Database (Denmark)

    Parshad, Henrik; Frydenvang, Karla Andrea; Liljefors, Tommy

    2004-01-01

    than those reported for the corresponding salts of benzylamine (I). Thermal analysis indicated that the increased solubility was caused by reduced crystal lattice energy, which was most likely due to the reduced number of strong hydrogen bonds of the salt of (II) and (III). X-ray crystallographic...... analysis of p-hydroxybenzoic acid salt of (I), (II) and (III) suggested that the reduced number of hydrogen bonds caused the apparent higher solubility. Further analyses of seven salts of (I) were performed. It was not possible to identify any relationship between the number of hydrogen bonds...

  18. Prediction of oral absorption of cinnarizine--a highly supersaturating poorly soluble weak base with borderline permeability.

    Science.gov (United States)

    Berlin, Mark; Przyklenk, Karl-Heinz; Richtberg, Annette; Baumann, Wolfgang; Dressman, Jennifer B

    2014-11-01

    Two important driving forces for oral absorption of active pharmaceutical ingredients are drug dissolution and permeability in the gastrointestinal tract. Poorly soluble weak bases typically exhibit high solubility under fasted gastric conditions. However, the solubility of such drugs usually decreases drastically in the fasted small intestine, constraining drug absorption. Since there is a discrepancy in solubility between the fasted state stomach and intestine, it is crucial to examine the influence of dissolution, supersaturation and precipitation on the oral absorption of poorly soluble weak bases during and after fasted state gastric emptying. Cinnarizine is a poorly soluble weak base with borderline permeability, exhibiting supersaturation and precipitation under simulated fasted state gastric emptying conditions. Interestingly, supersaturation and precipitation of cinnarizine under fed state conditions is not expected to occur, since the drug shows good solubility in fed state biorelevant media and exhibits a positive food effect in pharmacokinetic studies. The present work is aimed at investigating the dissolution, supersaturation and precipitation behavior of marketed cinnarizine tablets under fasted and fed state conditions using biorelevant dissolution and transfer methods. In order to predict the in vivo performance of these cinnarizine formulations, the in vitro results were then coupled with different physiologically based pharmacokinetic (PBPK) models, which considered either only dissolution or a combination of dissolution, supersaturation and precipitation kinetics. The results of the in silico predictions were then compared with in vivo observations. The study revealed that under fasting conditions, plasma profiles could be accurately predicted only when supersaturation and precipitation as well as dissolution were taken into account. It was concluded that for poorly soluble weak bases with moderate permeability, supersaturation and precipitation

  19. Cloud condensation nuclei activation of limited solubility organic aerosol

    Science.gov (United States)

    Huff Hartz, Kara E.; Tischuk, Joshua E.; Chan, Man Nin; Chan, Chak K.; Donahue, Neil M.; Pandis, Spyros N.

    The cloud condensation nuclei (CCN) activation of 19 organic species with water solubilities ( Csat) ranging from 10 -4 to 10 2 g solute 100 g -1 H 2O was measured. The organic particles were generated by nebulization of an aqueous or an alcohol solution. Use of alcohols as solvents enables the measurement of low solubility, non-volatile organic CCN activity and reduces the likelihood of residual water in the aerosol. The activation diameter of organic species with very low solubility in water ( Csat<0.3 g 100 g -1 H 2O) is in agreement with Köhler theory using the bulk solubility (limited solubility case) of the organic in water. Many species, including 2-acetylbenzoic acid, aspartic acid, azelaic acid, glutamic acid, homophthalic acid, phthalic acid, cis-pinonic acid, and salicylic acid are highly CCN active in spite of their low solubility (0.3 g 100 g -1 H 2O< Csat<1 g 100 g -1 H 2O), and activate almost as if completely water soluble. The CCN activity of most species is reduced, if the particles are produced using non-aqueous solvents. The existence of the particles in a metastable state at low RH can explain the observed enhancement in CCN activity beyond the levels suggested by their solubility.

  20. Synthesis and characterization of highly flexible thermoplastic films from cyanoethylated corn distillers dried grains with solubles.

    Science.gov (United States)

    Hu, Chunyan; Reddy, Narendra; Yan, Kelu; Yang, Yiqi

    2011-03-09

    Corn distillers dried grains with solubles (DDGS) can be made into highly flexible thermoplastic films without the need for plasticizers. DDGS is an abundantly available coproduct of ethanol production that is inexpensive ($80-130/ton) compared to most of the polymers used for thermoplastic applications. In this research, oil-and-zein-free DDGS was cyanoethylated using acrylonitrile, and cyanoethylation conditions were optimized to obtain high percent weight gain of up to 42%. Cyanoethylated DDGS was characterized using (1)H NMR, FTIR, DSC, and TGA. Cyanoethylated DDGS was compression molded into thermoplastic films, and the tensile properties of the films were studied. It was found that DDGS films with elongation as high as 38% and strength of 14 MPa could be obtained without the use of any plasticizers. Alternatively, films with strength as high as 651 MPa but with relatively low elongation (2.5%) were obtained by varying the extent of cyanoethylation. This research showed that cyanoethylation could be a viable approach to develop biothermoplastics from biopolymers for applications such as packing films, extrudates, and resins for composites.

  1. Properties and solubility of chrome in iron alumina phosphate glasses containing high level nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Huang, W. [School of Materials Science and Engineering, Tongji Univ., Shanghai, SH (China); Day, D.E.; Ray, C.S.; Kim, C.W.; Reis, S.T.D. [Univ. of Missouri-Rolla (United States). Graduate Center for Materials Research

    2004-10-01

    Chemical durability, glass formation tendency, and other properties of iron alumina phosphate glasses containing 70 wt% of a simulated high level nuclear waste (HLW), doped with different amounts of Cr{sub 2}O{sub 3}, have been investigated. All of the iron alumina phosphate glasses had an outstanding chemical durability as measured by their small dissolution rate (1 . 10{sup -9} g/(cm{sup 2} . min)) in deionized water at 90 C for 128 d, their low normalized mass release as determined by the product consistency test (PCT) and a barely measurable corrosion rate of <0.1 g/(m{sup 2} . d) after 7 d at 200 C by the vapor hydration test (VHT). The solubility limit for Cr{sub 2}O{sub 3} in the iron phosphate melts was estimated at 4.1 wt%, but all of the as-annealed melts contained a few percent of crystalline Cr{sub 2}O{sub 3} that had no apparent effect on the chemical durability. The chemical durability was unchanged after deliberate crystallization, 48 h at 650 C. These iron phosphate waste forms, with a waste loading of at least 70 wt%, can be readily melted in commercial refractory crucibles at 1250 C for 2 to 4 h, are resistant to crystallization, meet all current US Department of Energy requirements for chemical durability, and have a solubility limit for Cr{sub 2}O{sub 3} which is at least three times larger than that for borosilicate glasses. (orig.)

  2. Aqueous Processing for Printed Organic Electronics: Conjugated Polymers with Multistage Cleavable Side Chains.

    Science.gov (United States)

    Schmatz, Brian; Yuan, Zhibo; Lang, Augustus W; Hernandez, Jeff L; Reichmanis, Elsa; Reynolds, John R

    2017-09-27

    The ability to process conjugated polymers via aqueous solution is highly advantageous for reducing the costs and environmental hazards of large scale roll-to-roll processing of organic electronics. However, maintaining competitive electronic properties while achieving aqueous solubility is difficult for several reasons: (1) Materials with polar functional groups that provide aqueous solubility can be difficult to purify and characterize, (2) many traditional coupling and polymerization reactions cannot be performed in aqueous solution, and (3) ionic groups, though useful for obtaining aqueous solubility, can lead to a loss of solid-state order, as well as a screening of any applied bias. As an alternative, we report a multistage cleavable side chain method that combines desirable aqueous processing attributes without sacrificing semiconducting capabilities. Through the attachment of cleavable side chains, conjugated polymers have for the first time been synthesized, characterized, and purified in organic solvents, converted to a water-soluble form for aqueous processing, and brought through a final treatment to cleave the polymer side chains and leave behind the desired electronic material as a solvent-resistant film. Specifically, we demonstrate an organic soluble polythiophene that is converted to an aqueous soluble polyelectrolyte via hydrolysis. After blade coating from an aqueous solution, UV irradiation is used to cleave the polymer's side chains, resulting in a solvent-resistant, electroactive polymer thin film. In application, this process results in aqueous printed materials with utility for solid-state charge transport in organic field effect transistors (OFETs), along with red to colorless electrochromism in ionic media for color changing displays, demonstrating its potential as a universal method for aqueous printing in organic electronics.

  3. High pressure nanoelectrospray ionization mass spectrometry for analysis of aqueous solutions.

    Science.gov (United States)

    Rahman, Md Matiur; Mandal, Mridul Kanti; Hiraoka, Kenzo; Chen, Lee Chuin

    2013-11-07

    Nanoelectrospray ionization (nanoESI) with a very fine emitter and nanoliter solution flow rate is known to be suitable for aqueous solutions. However, under atmospheric pressure, its stability with aqueous solutions is not always guaranteed particularly in the negative ion mode where corona and arc discharge tend to occur more easily. Electrical discharge can be quenched to a certain extent by adding electron scavenging gases like SF6 or CO2 to the ion source. The onset potential that is required to induce the discharge also increases with an increase of gas pressure. Recently, we have reported on a series of high pressure electrospray ion sources that were stable in both positive and negative ion modes using air or N2 as the working gas. In this paper, we compare the performance of nanoelectrospray under atmospheric pressure and super-atmospheric pressure for the analysis of samples in aqueous solution. The comparative study was performed using the same ion source chamber that could be pressurized up to 6 bar. The pressure in the first pumping stage of the mass spectrometer was kept constant when the ion source pressure was changed by using an additional pump with variable pumping speed. High pressure nanoESI optimized at 2-3 bar demonstrated a 3-5 times improvement in ion signal intensity compared to atmospheric pressure nanoESI, and the signal stability was significantly improved particularly in the negative mode.

  4. A soluble form of the high affinity IgE receptor, Fc-epsilon-RI, circulates in human serum.

    Directory of Open Access Journals (Sweden)

    Eleonora Dehlink

    Full Text Available Soluble IgE receptors are potential in vivo modulators of IgE-mediated immune responses and are thus important for our basic understanding of allergic responses. We here characterize a novel soluble version of the IgE-binding alpha-chain of Fc-epsilon-RI (sFcεRI, the high affinity receptor for IgE. sFcεRI immunoprecipitates as a protein of ∼40 kDa and contains an intact IgE-binding site. In human serum, sFcεRI is found as a soluble free IgE receptor as well as a complex with IgE. Using a newly established ELISA, we show that serum sFcεRI levels correlate with serum IgE in patients with elevated IgE. We also show that serum of individuals with normal IgE levels can be found to contain high levels of sFcεRI. After IgE-antigen-mediated crosslinking of surface FcεRI, we detect sFcεRI in the exosome-depleted, soluble fraction of cell culture supernatants. We further show that sFcεRI can block binding of IgE to FcεRI expressed at the cell surface. In summary, we here describe the alpha-chain of FcεRI as a circulating soluble IgE receptor isoform in human serum.

  5. Highly Soluble Monoamino-Substituted Perylene Tetracarboxylic Dianhydrides: Synthesis, Optical and Electrochemical Properties

    Directory of Open Access Journals (Sweden)

    Kew-Yu Chen

    2014-12-01

    Full Text Available Three dialkylamino-substituted perylene tetracarboxylic dianhydrides with different n-alkyl chain lengths (n = 6, 12 or 18, 1a–1c, were synthesized under mild conditions in high yields and were characterized by 1H NMR, 13C NMR and high resolution mass spectroscopy. Their optical and electrochemical properties were measured using UV-Vis and emission spectroscopic techniques, as well as cyclic voltammetry (CV. This is the first time that the structures and the properties of monoamino-substituted perylene tetracarboxylic dianhydrides have been reported. These molecules show a deep green color in both solution and the solid state and are soluble in most organic solvents. They all show a unique charge transfer emission in the near-infrared region, and the associated peaks exhibit solvatochromism. The dipole moments of the compounds have been estimated using the Lippert-Mataga equation, and upon excitation, they show slightly larger dipole moment changes than those of corresponding perylene diimides, 2a–2c. Additionally, Compounds 1a–1c undergo two quasi-reversible one-electron oxidations and two quasi-reversible one-electron reductions in dichloromethane at modest potentials. Complementary density functional theory calculations performed on these chromophores are reported in order to gain more insight into their molecular structures and optical properties.

  6. Demonstration of sulfur solubility determinations in high waste loading, low-activity waste glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-04-25

    A method recommended by Pacific Northwest National Laboratory (PNNL) for sulfate solubility determinations in simulated low-activity waste glasses was demonstrated using three compositions from a recent Hanford high waste loading glass study. Sodium and sulfate concentrations in the glasses increased after each re-melting step. Visual observations of the glasses during the re-melting process reflected the changes in composition. The measured compositions showed that the glasses met the targeted values. The amount of SO3 retained in the glasses after washing was relatively high, ranging from 1.6 to 2.6 weight percent (wt %). Measured SnO2 concentrations were notably low in all of the study glasses. The composition of the wash solutions should be measured in future work to determine whether SnO2 is present with the excess sulfate washed from the glass. Increases in batch size and the amount of sodium sulfate added did not have a measureable impact on the amount of sulfate retained in the glass, although this was tested for only a single glass composition. A batch size of 250 g and a sodium sulfate addition targeting 7 wt %, as recommended by PNNL, will be used in future experiments.

  7. Highly Water-Soluble Magnetic Nanoparticles as Novel Draw Solutes in Forward Osmosis for Water Reuse

    KAUST Repository

    Ling, Ming Ming

    2010-06-16

    Highly hydrophilic magnetic nanoparticles have been molecularly designed. For the first time, the application of highly water-soluble magnetic nanoparticles as novel draw solutes in forward osmosis (FO) was systematically investigated. Magnetic nanoparticles functionalized by various groups were synthesized to explore the correlation between the surface chemistry of magnetic nanoparticles and the achieved osmolality. We verified that magnetic nanoparticles capped with polyacrylic acid can yield the highest driving force and subsequently highest water flux among others. The used magnetic nanoparticles can be captured by the magnetic field and recycled back into the stream as draw solutes in the FO process. In addition, magnetic nanoparticles of different diameters were also synthesized to study the effect of particles size on FO performance. We demonstrate that the engineering of surface hydrophilicity and magnetic nanoparticle size is crucial in the application of nanoparticles as draw solutes in FO. It is believed that magnetic nanoparticles will soon be extensively used in this area. © 2010 American Chemical Society.

  8. Borate glasses with high lanthanide oxids solubility for the cold crucible induction melter(CCIM) applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M.; Heo, J. [POSTECH, Pohang (Korea, Republic of)

    2016-05-15

    Pyro-processing is being investigated to reuse radioactive uranium and trans-uranium elements from the spent fuels. Previous researches regarding waste forms for rare-earth oxides waste generated from pyro-processing reported low elemental release (< 10{sup 4} g/m2) of RE ions at the product consistency test (PCT). Current work reports the continuing effort on the enhancement of the waste loading and process-ability using cold crucible induction melter(CCIM). Borate glasses are well-known for their low melting temperatures with high rare-earth oxide solubility compared to silicate glasses. Borate glasses were investigated as potential waste forms with high waste loading for immobilization of lanthanide ion wastes produced by pyro-processing. Process-ability of them was investigated by characterizing several important processing parameters for cold crucible induction melter (CCIM) process. Borate glasses containing 0 - 20 mol% Nd{sub 2}O{sub 3} were fabricated by melting the starting powders at 1300 .deg. C for 30 min with maximum loading of 56.8 wt % (22 mol %). The released concentration of Nd were < 0.1 ppm. Crystallization did not appear at the temperature below 800 .deg. C. Viscosity and electric conductivity of these glasses meet requirements to apply to CCIM.

  9. Equilibrium Total Pressure and CO2 Solubility in Binary and Ternary Aqueous Solutions of 2-(Diethylamino)ethanol (DEEA) and 3-(Methylamino)propylamine (MAPA)

    DEFF Research Database (Denmark)

    Waseem Arshad, Muhammad; Svendsen, Hallvard Fjøsne; Fosbøl, Philip Loldrup

    2014-01-01

    available calorimeter used as an equilibrium cell. The examined systems were the binary aqueous solutions of 5 M DEEA, 2 M MAPA, and 1 M MAPA and the ternary aqueous mixtures of 5 M DEEA + 2 M MAPA (5D2M) and 5 M DEEA + 1 M MAPA (5D1M), which gave liquid–liquid phase split upon CO2 absorption. The total......Equilibrium total pressures were measured and equilibrium CO2 partial pressures were calculated from the measured total pressure data in binary and ternary aqueous solutions of 2-(diethylamino)ethanol (DEEA) and 3-(methylamino)propylamine (MAPA). The measurements were carried out in a commercially...... pressures were measured and the CO2 partial pressures were calculated as a function of CO2 loading at three different temperatures 40 °C, 80 °C, and 120 °C. All experiments were reproduced with good repeatability. The measurements were carried out for 30 mass % MEA solutions to validate the experimental...

  10. Electrochemical deposition of coatings of highly entropic alloys from non-aqueous solutions

    Directory of Open Access Journals (Sweden)

    Jeníček V.

    2016-03-01

    Full Text Available The paper deals with electrochemical deposition of coatings of highly entropic alloys. These relatively new materials have been recently intensively studied. The paper describes the first results of electrochemical coating with highly entropic alloys by deposition from non-aqueous solutions. An electrochemical device was designed and coatings were deposited. The coatings were characterised with electronic microscopy scanning, atomic absorption spectrometry and X-ray diffraction methods and the combination of methods of thermic analysis of differential scanning calorimetry and thermogravimetry.

  11. High voltage rechargeable magnesium batteries having a non-aqueous electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Doe, Robert Ellis; Lane, George Hamilton; Jilek, Robert E.; Hwang, Jaehee

    2016-03-22

    A rechargable magnesium battery having an non-aqueous electrolyte is provided. The properties of the electrolyte include high conductivity, high Coulombic efficiency, and an electrochemical window that can exceed 3.5 V vs. Mg/Mg.sup.+2. The use of the electrolyte promotes the electrochemical deposition and dissolution of Mg without the use of any Grignard reagents, other organometallic materials, tetraphenyl borate, or tetrachloroaluminate derived anions. Other Mg-containing electrolyte systems that are expected to be suitable for use in secondary batteries are also described.

  12. Preparation of monodisperse aqueous microspheres containing high concentration of l-ascorbic acid by microchannel emulsification.

    Science.gov (United States)

    Khalid, Nauman; Kobayashi, Isao; Neves, Marcos A; Uemura, Kunihiko; Nakajima, Mitsutoshi; Nabetani, Hiroshi

    2015-01-01

    Monodisperse aqueous microspheres containing high concentrations of l-ascorbic acid with different concentrations of sodium alginate (Na-ALG) and magnesium sulfate (MgSO4) were prepared by using microchannel emulsification (MCE). The continuous phase was water-saturated decane containing a 5% (w/w) hydrophobic emulsifier. The flow rate of the continuous phase was maintained at 10 mL h(-1), whereas the pressure applied to the disperse phase was varied between 3 and 25 kPa. The disperse phase optimized for successfully generating aqueous microspheres included 2% (w/w) Na-ALG and 1% (w/w) MgSO4. At a higher MgSO4 concentration, the generated microspheres resulted in coalescence and subsequent bursting. At a lower MgSO4 concentration, unstable and polydisperse microspheres were obtained. The aqueous microspheres generated from the MCs under optimized conditions had a mean particle diameter (dav) of 14-16 µm and a coefficient of variation (CV) of less than 8% at the disperse phase pressures of 5-15 kPa.

  13. Determination of mitomycin C in human aqueous humor and serum by high-performance liquid chromatography.

    Science.gov (United States)

    Li, W Y; Seah, S K; Koda, R T

    1993-09-08

    Mitomycin C (MMC) is used in the treatment of disseminated adenocarcinoma of the stomach and pancreas and is used in ophthalmology as adjunctive therapy in trabeculectomy. Since only small volumes of aqueous humor are available for analysis, a sensitive method requiring limited sample preparation was developed. An internal standard, 4-aminoacetophenone, was added to aqueous humor specimens, and the solution was directly injected into the high-performance liquid chromatographic (HPLC) column. The use of a short 50-mm C18 reversed-phase column gave adequate resolution of peaks with improved sensitivity. The method was applicable for determination of MMC in serum, although solid-phase extraction for sample clean-up was required prior to injection into the HPLC column, and analytical columns of 150-250 mm were necessary for adequate resolution of peaks. The method has been validated and is linear from 6.25 to 50 ng/ml in aqueous humor and from 10 to 500 ng/ml in serum.

  14. Decreased plasma soluble erythropoietin receptor in high-altitude excessive erythrocytosis and Chronic Mountain Sickness.

    Science.gov (United States)

    Villafuerte, Francisco C; Macarlupú, José Luis; Anza-Ramírez, Cecilia; Corrales-Melgar, Daniela; Vizcardo-Galindo, Gustavo; Corante, Noemí; León-Velarde, Fabiola

    2014-12-01

    Excessive erythrocytosis (EE) is the hallmark of chronic mountain sickness (CMS), a prevalent syndrome in high-altitude Andean populations. Although hypoxemia represents its underlying stimulus, why some individuals develop EE despite having altitude-normal blood erythropoietin (Epo) concentration is still unclear. A soluble form of the Epo receptor (sEpoR) has been identified in human blood and competes directly for Epo with its membrane counterpart (mEpoR). Thus, reduced levels of circulating sEpoR could lead to higher Epo availability and ultimately to EE. We characterized the relationship between Epo and sEpoR, with hematocrit and hemoglobin concentration in healthy highlanders and CMS patients at 4,340 m in Cerro de Pasco, Peru. Our results show that EE patients show decreased plasma sEpoR levels and can be subdivided into two subgroups of normal and high plasma Epo concentration for the altitude of residence, with hemoglobin concentration rising exponentially with an increasing Epo-to-sEpoR ratio (Epo/sEpoR). Also, we showed that the latter varies as an inverse exponential function of arterial pulse O2 saturation. Our findings suggests that EE is strongly associated with higher Epo/sEpoR values, leading to elevated plasma Epo availability to bind mEpoR, and thereby a stronger stimulus for augmented erythropoiesis. Differences in the altitude normal and high Epo CMS patients with a progressively higher Epo/sEpoR supports the hypothesis of the existence of two genetically different subgroups suffering from EE and possibly different degrees of adaptation to chronic high-altitude hypoxia.

  15. IUPAC-NIST Solubility Data Series. 90. Hydroxybenzoic Acid Derivatives in Binary, Ternary, and Multicomponent Systems. Part I. Hydroxybenzoic Acids, Hydroxybenzoates, and Hydroxybenzoic Acid Salts in Water and Aqueous Systems

    Science.gov (United States)

    Goto, Rensuke; Fukuda, Hiroshi; Königsberger, Erich; Königsberger, Lan-Chi

    2011-03-01

    The solubility data for well-defined binary, ternary, and multicomponent systems of solid-liquid type are reviewed. One component, which is 2-, 3-, and 4-hydroxybenzoic acids, 4-hydroxybenzoate alkyl esters (parabens), or hydroxybenzoic acid salts, is in the solid state at room temperature and another component is liquid water, meaning that all of the systems are aqueous solutions. The ternary or multicomponent systems include organic substances of various classes (hydrocarbons of several structural types, halogenated hydrocarbons, alcohols, acids, ethers, esters, amides, and surfactants) or inorganic substances. Systems reported in the primary literature from 1898 through 2000 are compiled. For seven systems, sufficient binary data for hydroxybenzoic acids or parabens in water are available to allow critical evaluation. Almost all data are expressed as mass and mole fractions as well as the originally reported units, while some data are expressed as molar concentration.

  16. Analysis of SSLP and Soluble Protein Contents in Leaves of Mutants Induced by High Pressure in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    HE Xiu-ying; XU Shi-ping; LIAO Yao-ping; MAO Xing-xue; WENG Ke-nan; CHEN Zhao-ming; CHEN Yue-han; XIAO Wan-sheng

    2004-01-01

    Rice variety Yuexiangzhan and its mutants induced by high pressure were studied using microsatellite markers and soluble protein content analyses. Eleven of the 88 microsatellite primer pairs showed evident polymorphisms repeatedly, and the polymorphic frequencies were 3.4-11.3% between the mutants and Yuexiangzhan. The polymorphic markers were randomly located on chromosomes. The more similar the plant types of the mutants like their original variety, the less polymorphic loci were detected. In addition, there was variation in the soluble protein contents among the leaves of mutants,and the contents were significantly lower than those of the original variety.

  17. Direct measurement of gas solubility and diffusivity in poly(vinylidene fluoride) with a high-pressure microbalance

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Zecchin, Nicoletta; Rubin, Adam

    2005-01-01

    We present solubility and diffusion data for the gases methane and carbon dioxide in the polymer poly(vinylidene fluoride). The polymer was cut from extruded piping intended for use in offshore oil and gas applications. Measurements were carried out using a purpose-built high-pressure microbalance....... These properties were determined in the temperature range 80-120degreesC and in the pressure range 50-150bar for methane and 20-40bar for carbon dioxide. In general, good agreement was obtained for similar measurements reported in the literature. Solubility follows a Henry's law (linear) dependence with pressure...

  18. Highly soluble benzo[ghi]perylenetriimide derivatives: stable and air-insensitive electron acceptors for artificial photosynthesis

    NARCIS (Netherlands)

    Chen, H.C.; Hsu, C.P.; Reek, J.N.H.; Williams, R.M.; Brouwer, A.M.

    2015-01-01

    A series of new benzo[ghi]perylenetriimide (BPTI) derivatives has been synthesized and characterized. These remarkably soluble BPTI derivatives show strong optical absorption in the range of =300-500nm and have a high triplet-state energy of 1.67eV. A cyanophenyl substituent renders BPTI such a stro

  19. Soluble urokinase plasminogen activator receptor is a marker of dysmetabolism in HIV-infected patients receiving highly active antiretroviral therapy

    DEFF Research Database (Denmark)

    Andersen, Ove; Eugen-Olsen, Jesper; Kofoed, Kristian;

    2008-01-01

    Circulating soluble urokinase plasminogen activator receptor (suPAR) reflects the immune and pro-inflammatory status of the HIV-infected patient. Highly active antiretroviral therapy (HAART) suppresses suPAR. Independent of the immune response to HAART, suPAR remains elevated in some HIV-infected...

  20. Solubility controls on aluminum in drinking water at relatively low and high pH.

    Science.gov (United States)

    Kvech, Steve; Edwards, Marc

    2002-10-01

    Potential control of soluble aluminum in drinking water by formation of solids other than Al(OH)3 was examined. At pHs below 6.0, Al(+3) solids containing sulfate, silica or potassium are thermodynamically favored versus amorphous Al(OH)3; however, in this work no evidence could be obtained that solids other than Al(OH)3 would form in practice. At pHs above 9, aluminum and magnesium were discovered to form complex solid phases of approximate composition AlMg2(OH)7, AlMg2SiO2(OH)7 or Al(SiO2)2(OH)3 dependent on circumstance. Formation of these solids provide a mechanistic explanation for enhancements to precipitative softening obtained in practice by dosing Al(+3) salts; that is, improved flocculation/settling and removal of silica from water that interferes with calcium precipitation. The solids also maintain residual aluminum below regulatory guidelines at high pH > 9.5.

  1. Chlorine solubility in evolved alkaline magmas

    Directory of Open Access Journals (Sweden)

    M. R. Carroll

    2005-06-01

    Full Text Available Experimental studies of Cl solubility in trachytic to phonolitic melts provide insights into the capacity of alkaline magmas to transport Cl from depth to the earth?s surface and atmosphere, and information on Cl solubility variations with pressure, temperature and melt or fluid composition is crucial for understanding the reasons for variations in Cl emissions at active volcanoes. This paper provides a brief review of Cl solubility experiments conducted on a range of trachytic to phonolitic melt compositions. Depending on the experimental conditions the melts studied were in equilibrium with either a Cl-bearing aqueous fluid or a subcritical assemblage of low- Cl aqueous fluid + Cl-rich brine. The nature of the fluid phase(s was identified by examination of fluid inclusions present in run product glasses and the fluid bulk composition was calculated by mass balance. Chlorine concentrations in the glass increase with increasing Cl molality in the fluid phase until a plateau in Cl concentration is reached when melt coexists with aqueous fluid + brine. With fluids of similar Cl molality, higher Cl concentrations are observed in peralkaline phonolitic melts compared with peraluminous phonolitic melts; overall the Cl concentrations observed in phonolitic and trachytic melts are approximately twice those found in calcalkaline rhyolitic melts under similar conditions. The observed negative pressure dependence of Cl solubility implies that Cl contents of melts may actually increase during magma decompression if the magma coexists with aqueous fluid and Cl-rich brine (assuming melt-vapor equilibrium is maintained. The high Cl contents (approaching 1 wt% Cl observed in some melts/glasses from the Vesuvius and Campi Flegrei areas suggest saturation with a Cl-rich brine prior to eruption.

  2. Supercooling of aqueous dimethylsulfoxide solution at normal and high pressures: Evidence for the coexistence of phase-separated aqueous dimethylsulfoxide solutions of different water structures.

    Science.gov (United States)

    Kanno, H; Kajiwara, K; Miyata, K

    2010-05-21

    Supercooling behavior of aqueous dimethylsulfoxide (DMSO) solution was investigated as a function of DMSO concentration and at high pressures. A linear relationship was observed for T(H) (homogeneous ice nucleation temperature) and T(m) (melting temperature) for the supercooling of aqueous DMSO solution at normal pressure. Analysis of the DTA (differential thermal analysis) traces for homogeneous ice crystallization in the bottom region of the T(H) curve for a DMSO solution of R=20 (R: moles of water/moles of DMSO) at high pressures supported the contention that the second critical point (SCP) of liquid water should exist at P(c2)= approximately 200 MPa and at T(c2)temperature of SCP). The presence of two T(H) peaks for DMSO solutions (R=15, 12, and 10) suggests that phase separation occurs in aqueous DMSO solution (Rtemperatures (different liquid water structures [LDL-like and HDL-like structures (LDL: low-density liquid water, HDL: high-density liquid water)] in the pressure range of 120-230 MPa.

  3. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate

    Science.gov (United States)

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-08-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices.

  4. Highly Sensitive Fluorometric Hg2+ Biosensor with a Mercury(Ⅱ)-Specific Oligonucleotide (MSO) Probe and Water-Soluble Graphene Oxide (WSGO)

    Institute of Scientific and Technical Information of China (English)

    Liu Xingfen; Miao Likun; Jiang Xu; Ma Yanwen; Fan Quli; Huang Wei

    2011-01-01

    A highly sensitive and selective, "turn-on" and simple Hg2+ biosensor is reported by using water-soluble gra-phene oxide (WSGO) and dye-labeled mercury(Ⅱ)-specific oligonucleotide (MSO) probe. The probe is rich of thymine (T) and can readily form the stem-loop structure which consists of the T-Hg2+-T configuration. In the ab-sence of Hg2+, the probe exists as a random coil conformation which can be readily adsorbed on the surface of WSGO by strong noncovalent binding of bases, as a result, the fluorescence of the dye labeled on the terminus of the MSO is strongly quenched by the efficient electron/energy transfer from the dye to WSGO. Upon addition of Hg2+, the formation of the T-Hg2+-T structure releases the MSO from the surface of WSGO, resulting in a restora-tion of the fluorescence of dye-labeled MSO probe. Based on this observation, a highly sensitive and selective Hg2+ sensor is developed, which can work with "turn-on" mode in aqueous solutions at room temperature. By using the fluorometric method, the limit of detection for Hg2+ can reach picomolar range (187 pmol·L-1), and it is demonstrated that the biosensor is highly selective and only minimally perturbed by a wide range of non-specific metal ions.

  5. Solid Phase Speciation and Solubility of Vanadium in Highly Weathered Soils.

    Science.gov (United States)

    Wisawapipat, Worachart; Kretzschmar, Ruben

    2017-08-01

    Vanadium (V) is increasingly recognized both as a medical trace element with essential biological functions and as a potentially toxic environmental pollutant, yet the current knowledge on V speciation in soils is limited. Here, we investigated the chemical speciation and extractability of V in highly weathered tropical soils, which are often rich in V compared to soils of temperate climatic regions. Vanadium K-edge X-ray absorption near edge structure (XANES) spectra of soil samples, along with a range of reference compounds differing in V-oxidation state and coordination chemistry, revealed the predominance of V(4+/5+) in a primarily octahedral or tetrahedral coordination. The soil spectra were best fitted with linear combinations of reference spectra of V(4+) in the structure of kaolinite, V(5+) adsorbed to kaolinite, and other V(5+)-sorbed solids. Vanadate adsorbed to goethite, ferrihydrite, gibbsite, and/or Fe(III)-natural organic matter complexes and V(4+) in the structure of goethite may be present, but cannot unequivocally be distinguished from each other by XANES spectroscopy. Sequential and single chemical extractions provided complementary information on the solubility of V under various conditions. The most labile V fractions, interpreted as weakly and strongly adsorbed V(5+), are the most relevant to V mobility and bioavailability in the environment, and accounted for only ∼2% of total soil V. Our results demonstrate that kaolinite and Fe oxides can effectively sequester V in highly weathered soils by mechanisms of adsorption and structural incorporation and are relevant to other Fe-oxide-rich environments under acidic and oxic conditions.

  6. Modeling solubility and acid-base properties of some amino acids in aqueous NaCl and (CH3)4NCl aqueous solutions at different ionic strengths and temperatures.

    Science.gov (United States)

    Bretti, Clemente; Giuffrè, Ottavia; Lando, Gabriele; Sammartano, Silvio

    2016-01-01

    New potentiometric experiments have been performed in NaCl and in (CH3)4NCl media, to determine the protonation constants, the protonation enthalpy changes and the solubility of six natural α-amino acids, namely Glycine (Gly), Alanine (Ala), Valine (Val), Leucine (Leu), Serine (Ser) and Phenylalanine (Phe). The aim of the work is the rationalization of the protonation thermodynamics (log [Formula: see text], solubility and [Formula: see text]) in NaCl, determining recommended, tentative or provisional values in selected experimental conditions and to report, for the first time, data in a weak interacting medium, as (CH3)4NCl. Literature data analysis was performed selecting the most reliable values, analyzed together with new data here reported. Significant trends and similarities were observed in the behavior of the six amino acids, and in some cases it was possible to determine common parameters for the ionic strength and temperature dependence. In general, the first protonation step, relative to the amino group, is significantly exothermic (average value is [Formula: see text] = -44.5 ± 0.4 kJ mol(-1) at infinite dilution and T = 298.15 K), and the second, relative to the carboxylate group, is fairly close to zero ([Formula: see text] = -2.5 ± 1.6, same conditions). In both cases, the main contribution to the proton binding reaction is mainly entropic in nature. For phenylalanine and leucine, solubility measurements at different concentrations of supporting electrolyte allowed to determine total and specific solubility values, then used to obtain the Setschenow and the activity coefficients of all the species involved in the protonation equilibria. The values of the first protonation constant in (CH3)4NCl are lower than the corresponding values in NaCl, due to the weak interaction between the deprotonated amino group and (CH3)4N(+). In this light, differences between the protonation functions in NaCl and (CH3)4NCl were used for the quantification

  7. Intergranular stress corrosion cracking of welded ferritic stainless steels in high temperature aqueous environments

    Energy Technology Data Exchange (ETDEWEB)

    Fukuzuka, Toshio; Shimogori, Kazutoshi; Fujiwara, Kazuo; Tomari, Haruo (Kobe Steel Ltd. (Japan). Central Research and Development Lab.); Kanda, Masao

    1982-07-01

    In considering the application of ferritic stainless steels to heat exchanger tubing materials for moisture separator-reheaters in LWRs, the effects of environmental conditions (temperature, chloride, dissolved oxygen, pH), thermal history, and steel composition (content of C, N, Cr and Ti) on the Inter-Granular Stress Corrosion Cracking (IGSCC) in high temperature aqueous environments, were studied. The IGSCC was proved to depend on steel composition and thermal history rather than environment. From these results, a steel was designed to prevent IGSCC of the welding HAZ for 18Cr and 13Cr steels.

  8. Development of highly luminescent and cytocompatible near-IR-emitting aqueous Ag2S quantum dots

    OpenAIRE

    Hocaoğlu, İbrahim; Sennaroğlu, Alphan ; Acar, Funda Havva Yağcı; Çizmeciyan, M. Natali; Erdem, Rengin ; Özen, Can ; Kurt, Adnan

    2012-01-01

    Colloidally stable and highly luminescent near-IR emitting Ag2S quantum dots (NIRQDs) were prepared by a very simple aqueous method using 2-mercaptopropionic acid (2MPA) as a coating. Emission of Ag2S-2MPA NIRQDs can be tuned between 780 and 950 nm. These NIRQDs have photoluminescence quantum yields (PLQY) around 7–39% and exhibit excellent cytocompatibility even at 600 mg mL 1 in NIH/3T3 cells. With such improved properties, Ag2S-2MPA NIRQDs have a great potential in practical...

  9. Synthesis of Highly Emissive CdSe Quantum Dots by Aqueous Precipitation Method

    OpenAIRE

    Bing Gao; Chao Shen; Shuanglong Yuan; Yunxia Yang; Guorong Chen

    2013-01-01

    CdSe quantum dots (QDs) with high quantum yield (QY) up to 76.57% are synthesized using the aqueous precipitation method. With the control of SeSO32- concentration in Se precursor, the nucleation speed and concentration of CdSe QDs are increased. The mass of obtained Cd2+ and Se2+ in nanocrystal is measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). XRD and HRTEM are used to identify the crystal phase and morphology of the products which are pure CdSe crystals in th...

  10. CHEMICAL ANALYSIS OF SIMULATED HIGH LEVEL WASTE GLASSES TO SUPPORT SULFATE SOLUBILITY MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Marra, J.

    2014-08-14

    The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms both within the DOE complex and to some extent at U.K. sites. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerated cleanup missions. Much of the previous work on improving sulfate retention in waste glasses has been done on an empirical basis, making it difficult to apply the findings to future waste compositions despite the large number of glass systems studied. A more fundamental, rather than empirical, model of sulfate solubility in glass, under development at Sheffield Hallam University (SHU), could provide a solution to the issues of sulfate solubility. The model uses the normalized cation field strength index as a function of glass composition to predict sulfate capacity, and has shown early success for some glass systems. The objective of the current scope is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DOE waste vitrification efforts, allowing for enhanced waste loadings and waste throughput. A series of targeted glass compositions was selected to resolve data gaps in the current model. SHU fabricated these glasses and sent samples to the Savannah River National Laboratory (SRNL) for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for simulated waste glasses fabricated SHU in support of sulfate solubility model development. A review of the measured compositions revealed that there are issues with the B{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} concentrations

  11. SITE-94. Radionuclide solubilities for SITE-94

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, R.; Apted, M. [QuantiSci, Denver, CO (United States)

    1996-12-01

    In this report, solubility constraints are evaluated on radioelement source-term concentrations supporting the SITE-94 performance assessment. Solubility models are based on heterogeneous-equilibrium, mass- and charge-balance constraints incorporated into the EQ3/6 geochemical software package, which is used to calculate the aqueous speciation behavior and solubilities of U, Th, Pu, Np, Am, Ni, Ra, Se, Sn, Sr, Tc and Zr in site groundwaters and near-field solutions. The chemical evolution of the near field is approximated using EQ3/6 in terms of limiting conditions at equilibrium, or steady state, in three closed systems representing fully saturated bentonite, Fe{sup o} corrosion products of the canister, and spent fuel. The calculations consider both low-temperature (15 deg C) and high-temperature (80 deg C) conditions in the near field, and the existence of either reducing or strongly oxidizing conditions in each of the bentonite, canister, and spent-fuel barriers. Heterogeneities in site characteristics are evaluated through consideration of a range of initial groundwaters and their interactions with engineered barriers. Aqueous speciation models for many radioelements are constrained by thermodynamic data that are estimated with varying degrees of accuracy. An important question, however, is how accurate do these models need to be for purposes of estimating source-term concentrations? For example, it is unrealistic to expect a high degree of accuracy in speciation models if such models predict solubilities that are below the analytical detection limit for a given radioelement. From a practical standpoint, such models are irrelevant if calculated solubilities cannot be tested by direct comparison to experimental data. In the absence of models that are both accurate and relevant for conditions of interest, the detection limit could define a pragmatic upper limit on radioelement solubility 56 refs, 25 tabs, 10 figs

  12. Effects of PVP K30 on Aqueous Solubility and Dissolution Properties of Daidzein%PVP K30 对葛根黄豆苷元溶解度和溶出的影响

    Institute of Scientific and Technical Information of China (English)

    郭圣荣; 郭丽

    2004-01-01

    Aim To study effects of PVP K30 on the aqueous solubility and dissolution properties of daidzein.Methods To measure the aqueous solubility and dissolution rates of daidzein in three different states (within solid dispersions, physical mixtures and as a pure drug) and investigate drug-polymer interactions in the solid state using X-ray powder diffraction and fourier-transform infrared spectroscopy.Results The negative values of the Gibbs free energy and enthalpy of transfer explained the spontaneous transfer of daidzein from phosphate buffer solution (PBS) to a solution of PVP in PBS.X-ray powder diffraction patterns showed that the drug was in the amorphous state (ratio of the drug ∶ PVP<1∶5) when dispersed in PVP K30.The infrared spectra indicated there exist interactions between the OH of daidzein and the C=O of PVP K30.Conclusion the dispersion of daidzein in PVP K30 considerably enhances the solubility and dissolution rate.%目的研究PVP K30 对葛根黄豆苷元水溶解性和溶出性质的影响.方法测量葛根黄豆苷元及其固体分散体、物理混合物的水溶解度和溶出速度,并用X-射线衍射、IR表征药物与PVP在固态条件下的相互作用.结果 Gibbs自由能和转移焓均小于零,表明葛根黄豆苷元从磷酸盐缓冲溶液中转移到PVP的磷酸盐缓冲溶液中是一自发的过程;X-射线衍射结果表明葛根黄豆苷元在PVP固体分散体(药物∶PVP < 1∶5)中以无定形形式存在; IR结果表明葛根黄豆苷元的羟基与PVP分子中的C=O之间存在相互作用.结论葛根黄豆苷元的PVP分散体可大大提高药物溶解度和溶出速度.

  13. Electrodeposition of Sm–Co film with high Sm content from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Long, Xiong-fei; Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn; Li, Xin-hua; Xia, Qing-lin; Zhang, Jin-fang

    2013-12-02

    Sm–Co films with high Sm content were electrodeposited by potentiostat technique from the aqueous solution containing glycine as a complexing agent. The Cyclic Voltammetry measurements showed that the glycine plays a crucial role in the electrodeposition of Sm–Co films. The forming of stable complex [Co{sup II}Sm{sup III}(Gly{sup −}){sub 2}(HGly{sup ±})]{sup 3+} facilitated the codeposition of Sm with Co at relatively low potential, which made it possible to fabricate the Sm–Co films with high Sm content. The Sm–Co film with 43 at.% Sm had been obtained. X-ray diffraction showed that the as-deposited Sm–Co films were amorphous. After annealing at 600 °C for 2 h in Ar atmosphere, the films became crystalline and the permanent Sm{sub 2}Co{sub 17} phase was formed, which significantly enhanced the coercivity of the films. - Highlights: • The Sm–Co film with high Sm content is electrodeposited from aqueous solutions. • The addition of glycine facilitates the codeposition of Sm with Co at relatively low potential. • The Sm{sub 2}Co{sub 17} phase is formed in the annealed Sm–Co film.

  14. Highly Oriented ZnO Rod Arrays on Si Substrates from Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    LIU Changsong; LI Zhiwen; ZHANG Qifeng

    2008-01-01

    Ordered zinc oxide (ZnO) rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers(SAMs). In the very early growth stage, the oriented ZnO crystals had already grown, which appeared to be themain reason why ZnO nanorods showed very high orientation. The un-dense and un-uniform SAMs provided a surface that was heterogeneous to ZnO nucleation. Consequently, highly oriented ZnO rods were selectively grown on the "coin-like" SAM-uncovered regions. The route developed here can provide some helpful information to control the nucleation and orientation of ZnO in aqueous solution. Also, the site-selective growth mechanisms can indicate a clue to grow patterned highly oriented ZnO nanorod arrays by the organic template.

  15. Solubility of natural gases in water under high pressure; Solubilite des gaz naturels dans l`eau a pression elevee

    Energy Technology Data Exchange (ETDEWEB)

    Dhima, A.

    1998-10-08

    Under high pressure (up to 1200 bar) and high temperature (up to 200 deg C) petroleum reservoir conditions the hydrocarbon-water mutual solubilities may become important. Under such conditions, the prediction of hydrocarbon water solubilities is a challenge for petroleum engineers. Indeed, very few studies have been done ar pressures higher that 700 bars. New solubility data for methane, ethane, n-butane, CO{sub 2} and their mixtures in pure water were obtained at 344.25 K and from 2.5 to 100 MPa. The results agree very well with those of the literature in the case of pure hydrocarbons in water, but differ for the hydrocarbon mixtures. A rigorous thermodynamic analysis allows the elaboration of a model that combines a cubic equation of state (Peng-Robinson with k{sub ij} given in literature) with the Henry`s law approach. The (P,T) functional form of Henry`s constant is given by the Krichevsky-Kasarnovsky equation which involves two important parameters: partial molar volume at infinite dilution and Henry`s constant at the vapour pressure of water. For a given solute both parameters are only functions of temperature. A critical selection of binary solubility data for a large number of solutes has been used as a basis for a new correlation for calculating both this partial molar volume and the corresponding Henry`s constants as a function of temperature. (author) 169 refs.

  16. The effects of the aqueous extract and residue of Matcha on the antioxidant status and lipid and glucose levels in mice fed a high-fat diet.

    Science.gov (United States)

    Xu, Ping; Ying, Le; Hong, Gaojie; Wang, Yuefei

    2016-01-01

    Matcha is a kind of powdered green tea produced by grinding with a stone mill. In the present study, the preventive effects of the aqueous extract (water-soluble) and residue (water-insoluble) of Matcha on the antioxidant status and lipid and glucose levels in mice fed a high-fat diet were investigated. Mice were fed seven different experimental diets for 4 weeks: a normal diet control (NC), a high-fat diet (HF), a high-fat diet with 0.025% Matcha (MLD), a high-fat diet with 0.05% Matcha (MMD), a high-fat diet with 0.075% Matcha (MHD), a high-fat diet with 0.05% Matcha aqueous extracts (ME), and a high-fat diet with 0.05% Matcha residues (MR). It was found that serum total cholesterol (TC) and triglyceride (TG) levels of the MHD group were significantly decreased compared to those of the HF group. Furthermore, in the MHD group, the level of high-density lipoprotein-cholesterol (HDL-C) was elevated, on the contrary the level of low-density lipoprotein-cholesterol (LDL-C) was suppressed. Moreover, Matcha could significantly lower the blood glucose levels, and improve the superoxide dismutase (SOD) activity and malondialdehyde (MAD) contents both in serum and liver; besides, the serum GSH-Px activity indicated that the oxidative stress caused by HF could be reversed by administration of Matcha. These findings suggest that Matcha has beneficial effects through the suppression of the blood glucose (BG) accumulation and promotion of the lipid metabolism and antioxidant activities. Moreover, the water-insoluble part of Matcha is suggested to play an important role in the suppression of diet-induced high levels of lipid and glucose.

  17. High serum soluble α-Klotho levels in patients with autosomal dominant polycystic kidney disease.

    Science.gov (United States)

    Sari, Funda; Inci, Ayca; Dolu, Suleyman; Ellidag, Hamit Yasar; Cetinkaya, Ramazan; Ersoy, Fettah Fevzi

    2017-02-01

    This study aims to determine fibroblast growth factor-23 and soluble α-Klotho levels in patients with autosomal dominant polycystic kidney disease. A total of 76 patients with autosomal dominant polycystic kidney disease and 32 healthy volunteers were included in the study. Serum fibroblast growth factor-23 and soluble α-Klotho levels were measured with ELISA kits. Parathyroid hormone, phosphate, calcium, creatinine, 25-hydroxyvitamin D3 levels, urinary protein to creatinine ratio and estimated glomerular filtration rate were also measured or calculated. Patients with autosomal dominant polycystic kidney disease had significantly higher serum parathyroid hormone (pserum 25-hydroxyvitamin D3 levels (pSerum fibroblast growth factor-23, soluble α-Klotho and 25-hydroxyvitamin D3 levels were similar in all five chronic kidney disease stages of autosomal dominant polycystic kidney disease (p>0.05). Fibroblast growth factor-23 (r=-0.251, p=0.034) and soluble α-Klotho levels (r=-0.251, p=0.034) were found to be negatively correlated with estimated glomerular filtration rate. This study shows increased fibroblast growth factor-23 levels in patients with autosomal dominant polycystic kidney disease which is in harmony with the general trend in patients with chronic kidney disease of other aetiologies, but, unlike them, also a significant increase in serum soluble α-Klotho levels in patients with autosomal dominant polycystic kidney disease suggesting an aberrant production or a decreased clearance of α-Klotho molecule. Considering the unique increases in erythropoietin levels due to erythropoietin production in renal cysts, we assume, patients with autosomal dominant polycystic kidney disease may potentially have different soluble α-Klotho production/clearance characteristics than the patients with other parenchymal renal diseases.

  18. Interfacial nano-biosensing in microfluidic droplets for high-sensitivity detection of low-solubility molecules.

    Science.gov (United States)

    Dou, Maowei; García, José Mireles; Zhan, Sihui; Li, XiuJun

    2016-02-28

    Taking advantage of the properties of the high surface-area-to-volume ratio of microfluidic droplets, we developed an innovative interfacial nanosensing strategy based on aptamer-functionalized graphene oxide nanosensors in microfluidic droplets for the high-sensitivity one-step detection of 17β-estradiol and other low-solubility molecules, with the detection sensitivity improved by about 3 orders of magnitude compared to conventional systems.

  19. C-104 high-level waste solids: Washing/leaching and solubility versus temperature studies

    Energy Technology Data Exchange (ETDEWEB)

    GJ Lumetta; DJ Bates; JP Bramson; LP Darnell; OT Farmer III; SK Fiskum; LR Greenwood; FV Hoopes; CZ Soderquist; MJ Steele; RT Steele; MW Urie; JJ Wagner

    2000-05-17

    This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing and caustic leaching on the composition of the C-104 HLW solids. The objective of this work was to determine the composition of the C-104 solids remaining after washing with 0.01 M NaOH or leaching with 3 M NaOH. Another objective of this test was to determine the solubility of the C-104 solids as a function of temperature. The work was conducted according to test plan BNFL-TP-29953-8, Rev. 0, ``Determination of the Solubility of HLW Sludge Solids.

  20. Highly Potent, Water Soluble Benzimidazole Antagonist for Activated (alpha)4(beta)1 Integrin

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, R D; Andrei, M; Lau, E Y; Lightstone, F C; Liu, R; Lam, K S; Kurth, M J

    2007-08-29

    The cell surface receptor {alpha}{sub 4}{beta}{sub 1} integrin, activated constitutively in lymphoma, can be targeted with the bisaryl urea peptidomimetic antagonist 1 (LLP2A). However, concerns on its preliminary pharmacokinetic (PK) profile provided an impetus to change the pharmacophore from a bisaryl urea to a 2-arylaminobenzimidazole moiety resulting in improved solubility while maintaining picomolar potency [5 (KLCA4); IC{sub 50} = 305 pM]. With exceptional solubility, this finding has potential for improving PK to help diagnose and treat lymphomas.

  1. Thermodynamic modeling of the solubility of CO2 in aqueous alkanolamine solutions using the extended UNIQUAC model Application to monoethanolamine and methyldiethanolamine

    DEFF Research Database (Denmark)

    Faramarzi, Leila; Kontogeorgis, Georgios; Thomsen, Kaj;

    2009-01-01

    -water systems in a wide range of temperature (-20-200 degrees C) were used. The application of the model to a large number of experimental data for representation of total pressure over the absorbent solutions (25-200 degrees C), correlation of the excess enthalpy and freezing point depression of the binary......The extended UNIQUAC model as proposed by Thomsen and Rasmussen [K. Thomsen, P. Rasmussen, Chem. Eng. Sci. 54 (1999) 1787-1802] was applied to the thermodynamic representation of carbon dioxide absorption in aqueous monoethanolamine (MEA) and methyldiethanolamine (MDEA) solutions. All the essential...... parameters of the model are simultaneously regressed to a set of data on the MEA and MDEA systems. Freezing point depression, vapor liquid equilibrium (VLE) and excess enthalpy (H-E) data of the binary systems of MEA-water and MDEA-water, VLE data on the ternary CO2-MEA-water as well as CO2-MDEA...

  2. CORM-EDE1: A Highly Water-Soluble and Nontoxic Manganese-Based photoCORM with a Biogenic Ligand Sphere.

    Science.gov (United States)

    Mede, Ralf; Klein, Moritz; Claus, Ralf A; Krieck, Sven; Quickert, Stefanie; Görls, Helmar; Neugebauer, Ute; Schmitt, Michael; Gessner, Guido; Heinemann, Stefan H; Popp, Jürgen; Bauer, Michael; Westerhausen, Matthias

    2016-01-01

    [Mn(CO)5Br] reacts with cysteamine and 4-amino-thiophenyl with a ratio of 2:3 in refluxing tetrahydrofuran to the complexes of the type [{(OC)3Mn}2(μ-SCH2CH2NH3)3]Br2 (1, CORM-EDE1) and [{(OC)3Mn}2(μ-SC6H4-4-NH3)3]Br2 (2, CORM-EDE2). Compound 2 precipitates during refluxing of the tetrahydrofuran solution as a yellow solid whereas 1 forms a red oil that slowly solidifies. Recrystallization of 2 from water yields the HBr-free complex [{(OC)3Mn}2(μ-S-C6H4-4-NH2)2(μ-SC6H4-4-NH3)] (3). The n-propylthiolate ligand (which is isoelectronic to the bridging thiolate of 1) leads to the formation of the di- and tetranuclear complexes [(OC)4Mn(μ-S-nPr)2]2 and [(OC)3Mn(μ-S-nPr)]4. CORM-EDE1 possesses ideal properties to administer carbon monoxide to biological and medicinal tissues upon irradiation (photoCORM). Isolated crystalline CORM-EDE1 can be handled at ambient and aerobic conditions. This complex is nontoxic, highly soluble in water, and indefinitely stable therein in the absence of air and phosphate buffer. CORM-EDE1 is stable as frozen stock in aqueous solution without any limitations, and these stock solutions maintain their CO release properties. The reducing dithionite does not interact with CORM-EDE1, and therefore, the myoglobin assay represents a valuable tool to study the release kinetics of this photoCORM. After CO liberation, the formation of MnHPO4 in aqueous buffer solution can be verified.

  3. Pure Phase Solubility Limits: LANL

    Energy Technology Data Exchange (ETDEWEB)

    C. Stockman

    2001-01-26

    The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO{sub 2} partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility

  4. Evidence for organic synthesis in high temperature aqueous media - facts and prognosis

    Science.gov (United States)

    Simoneit, Bernd R. T.

    1995-01-01

    Hydrothermal systems are common along the active tectonic areas of the earth. Potential sites being studied for organic matter alteration and possible organic synthesis are spreading ridges, off-axis systems, back-arc activity, hot spots, volcanism, and subduction. Organic matter alteration, primarily reductive and generally from immature organic detritus, occurs in these high temperature and rapid fluid flow hydrothermal regimes. Hot circulating water (temperature range - warm to greater than 400 C) is responsible for these molecular alterations, expulsion and migration. Compounds that are obviously synthesized are minor components because they are generally masked by the pyrolysis products formed from contemporary natural organic precursors. The reactivity of organic compounds in hot water (200-350 C) has been studied in autoclaves, and supercritical water as a medium for chemistry has also been evaluated. This high temperature aqueous organic chemistry and the strong reducing conditions of the natural systems suggest this as an important route to produce organic compounds on the primitive earth. Thus a better understanding of the potential syntheses of organic compounds in hydrothermal systems will require investigations of the chemistry of condensation, autocatalysis, catalysis and hydrolysis reactions in aqueous mineral buffered systems over a range of temperatures from warm to greater than 400 C.

  5. Evidence for organic synthesis in high temperature aqueous media - facts and prognosis

    Science.gov (United States)

    Simoneit, Bernd R. T.

    1995-01-01

    Hydrothermal systems are common along the active tectonic areas of the earth. Potential sites being studied for organic matter alteration and possible organic synthesis are spreading ridges, off-axis systems, back-arc activity, hot spots, volcanism, and subduction. Organic matter alteration, primarily reductive and generally from immature organic detritus, occurs in these high temperature and rapid fluid flow hydrothermal regimes. Hot circulating water (temperature range - warm to greater than 400 C) is responsible for these molecular alterations, expulsion and migration. Compounds that are obviously synthesized are minor components because they are generally masked by the pyrolysis products formed from contemporary natural organic precursors. The reactivity of organic compounds in hot water (200-350 C) has been studied in autoclaves, and supercritical water as a medium for chemistry has also been evaluated. This high temperature aqueous organic chemistry and the strong reducing conditions of the natural systems suggest this as an important route to produce organic compounds on the primitive earth. Thus a better understanding of the potential syntheses of organic compounds in hydrothermal systems will require investigations of the chemistry of condensation, autocatalysis, catalysis and hydrolysis reactions in aqueous mineral buffered systems over a range of temperatures from warm to greater than 400 C.

  6. High-contrast fluorescence sensing of aqueous Cu(I) with triarylpyrazoline probes: dissecting the roles of ligand donor strength and excited state proton transfer.

    Science.gov (United States)

    Morgan, M Thomas; Bagchi, Pritha; Fahrni, Christoph J

    2013-03-07

    Cu(I)-responsive fluorescent probes based on a photoinduced electron transfer (PET) mechanism generally show incomplete fluorescence recovery relative to the intrinsic quantum yield of the fluorescence reporter. Previous studies on probes with an N-aryl thiazacrown Cu(I)-receptor revealed that the recovery is compromised by incomplete Cu(I)-N coordination and resultant ternary complex formation with solvent molecules. Building upon a strategy that successfully increased the fluorescence contrast and quantum yield of Cu(I) probes in methanol, we integrated the arylamine PET donor into the backbone of a hydrophilic thiazacrown ligand with a sulfonated triarylpyrazoline as a water-soluble fluorescence reporter. This approach was not only expected to disfavor ternary complex formation in aqueous solution but also to maximize PET switching through a synergistic Cu(I)-induced conformational change. The resulting water-soluble probe 1 gave a strong 57-fold fluorescence enhancement upon saturation with Cu(I) with high selectivity over other cations, including Cu(II), Hg(II), and Cd(II); however, the recovery quantum yield did not improve over probes with the original N-aryl thiazacrown design. Concluding from detailed photophysical data, including responses to acidification, solvent isotope effects, quantum yields, and time-resolved fluorescence decay profiles, the fluorescence contrast of 1 is compromised by inadequate coordination of Cu(I) to the weakly basic arylamine nitrogen of the PET donor and by fluorescence quenching via two distinct excited state proton transfer pathways operating under neutral and acidic conditions.

  7. Tuning ionic liquids for high gas solubility and reversible gas sorption

    DEFF Research Database (Denmark)

    Huang, Jun; Riisager, Anders; Berg, Rolf W.

    2008-01-01

    a moderate association between gas and liquid, which also could be confirmed by Raman and UV–vis spectroscopy on the gas-saturated (1 bar) ionic liquids. Knowledge of gas solubilities and the reversible gas absorption capacity of ionic liquids are believed to have importance for their possible application...

  8. Elastohydrodynamics of oil-soluble PAGs, high-oleic sunflower oil and their blends

    Science.gov (United States)

    Recent reports indicate that the oxidative stability of vegetable oils can be improved for lubrication purposes by mixing them with oil-soluble polyalkyl glycols (OS-PAG). This inspired a study of other lubrication-related properties of their blends. The viscosity, density, and elastohydrodynamic fi...

  9. Direct measurement of gas solubilities in polymers with a high-pressure microbalance

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Nielsen, Johannes Kristoffer; Hassager, Ole

    2004-01-01

    for methane, for which negative deviations from Henry's law behavior were observed. The diffusion coefficients for each of the gases in the polymer were also measured with the balance, although the uncertainty was greater than for the solubility measurements. (C) 2003 Wiley Periodicals, Inc. J Appl Polyrn Sci...

  10. Influence of the ligand alkyl chain length on the solubility, aqueous speciation, and kinetics of substitution reactions of water-soluble M3S4 (M = Mo, W) clusters bearing hydroxyalkyl diphosphines.

    Science.gov (United States)

    Beltrán, Tomás F; Llusar, Rosa; Sokolov, Maxim; Basallote, Manuel G; Fernández-Trujillo, M Jesús; Pino-Chamorro, Jose Ángel

    2013-08-05

    Water-soluble [M3S4X3(dhbupe)3](+) diphosphino complexes (dhbupe = 1,2-bis(bis(hydroxybutyl)phosphino)ethane), 1(+) (M = Mo, X = Cl) and 2(+) (M = W; X = Br), have been synthesized by extending the procedure used for the preparation of their hydroxypropyl analogues by reaction of the M3S4(PPh3)3X4(solvent)x molecular clusters with the corresponding 1,2-bis(bishydroxyalkyl)diphosphine. The solid state structure of the [M3S4X3(dhbupe)3](+) cation possesses a C3 symmetry with a cuboidal M3S4 unit, and the outer positions are occupied by one halogen and two phosphorus atoms of the diphosphine ligand. At a basic pH, the halide ligands are substituted by hydroxo groups to afford the corresponding [Mo3S4(OH)3(dhbupe)3](+) (1OH(+)) and [W3S4(OH)3(dhbupe)3](+) (2OH(+)) complexes. This behavior is similar to that found in 1,2-bis(bis(hydroxymethyl)phosphino)ethane (dhmpe) complexes and differs from that observed for 1,2-bis(bis(hydroxypropyl)phosphino)ethane (dhprpe) derivatives. In the latter case, an alkylhydroxo group of the functionalized diphosphine replaces the chlorine ligands to afford Mo3S4 complexes in which the deprotonated dhprpe acts in a tridentate fashion. Detailed studies based on stopped-flow, (31)P{(1)H} NMR, and electrospray ionization mass spectrometry techniques have been carried out in order to understand the solution behavior and kinetics of interconversion between the different species formed in solution: 1 and 1OH(+) or 2 and 2OH(+). On the basis of the kinetic results, a mechanism with two parallel reaction pathways involving water and OH(-) attacks is proposed for the formal substitution of halides by hydroxo ligands. On the other hand, reaction of the hydroxo clusters with HX acids occurs with protonation of the OH(-) ligands followed by substitution of coordinated water by X(-).

  11. Highly selective and sensitive fluorescent chemosensor for femtomolar detection of silver ion in aqueous medium

    Directory of Open Access Journals (Sweden)

    Abraham Daniel Arulraj

    2015-12-01

    Full Text Available The chemical sensing for the trace level detection of silver ion in aqueous solution still remains a challenge using simple, rapid, and inexpensive method. We report that thionine can be used as a fluorescent probe for the detection of Ag+ ion. The successive addition of Ag+ ion to the solution containing thionine quenches (turns-off the fluorescence intensity of thionine. Association and quenching constants have been estimated by the Benesi–Hildebrand method and Stern–Volmer plot, respectively. From the plot, the nature of the fluorescence quenching was confirmed as static quenching. An important feature of our chemosensor is high selectivity towards the determination of silver ion in aqueous solution over the other competitive metal ions. The detection limit of the sensor achieved 5 fM for Ag+ ion, which is superior to all previously reported chemosensors. The NMR and FT-IR studies were also carried out to support the complex formation between thionine and Ag+ ion. The practicality of the proposed chemosensor for determination of Ag+ ion was carried in untreated water samples.

  12. Hypolipidemic effects of aqueous extract of Acalypha capitata leaves in rats fed on high cholesterol diet

    Institute of Scientific and Technical Information of China (English)

    Nnodim Johnkennedy; Emejulu Adamma; Nwadike Constance Nnedimma

    2011-01-01

    Objective:To evaluate the hypolipidemic effects of aqueous extract of Acalypha capitata (A. capitata) leaves in rats fed on high cholesterol diet. Methods:Cholesterol diet was administered to Wistar rats at a dose of 40 mg per 0.2 mL 3 times daily for 14 days while the control received distilled water. These animals were treated with extract of A. capitata at doses of 100 and 200 mg/kg. Lipid profiles were observed and compared. Results:Administration of A. capitata caused significant decrease in cholesterol, triglyceride and low density lipoprotein-cholesterol when compared with the control (P<0.05) which was dose dependent. Also, it was observed that high density lipoprotein-cholesterol was significantly increased when compared with the control. Conclusions:This observation suggests that the leaf extract of A. capitata could probably serve as a potential natural product for treatment of hyperlipidaemia.

  13. Soluble urokinase receptor levels in plasma during 5 years of highly active antiretroviral therapy in HIV-1-infected patients

    DEFF Research Database (Denmark)

    Ostrowski, Sisse R; Katzenstein, Terese L; Piironen, Timo;

    2004-01-01

    High blood levels of the soluble urokinase receptor (suPAR) strongly predict increased mortality in human immunodeficiency virus-1 (HIV-1)-infected patients. This study investigated the plasma concentration of suPAR in 29 treatment-naive HIV-1-infected patients during 5 years treatment with highly...... active antiretroviral therapy (HAART). Plasma suPAR decreased after introducing HAART, most pronounced during the first treatment year. The change in plasma suPAR was independent of changes in viral replication and CD4+ cells but it was strongly correlated with plasma levels of the soluble TNF receptor...... is linked to inflammation in untreated as well as HAART-treated HIV-1-infected patients....

  14. High-Yield Synthesis of Silver Nanoparticles by Precipitation in a High-Aqueous Phase Content Reverse Microemulsion

    Directory of Open Access Journals (Sweden)

    Y. D. Sosa

    2010-01-01

    Full Text Available Silver nanoparticles were precipitated at 70°C in a reverse microemulsion containing a high concentration of 0.5 M silver nitrate aqueous solution, toluene as organic phase, and a mixture of surfactants sodium bis (2-ethylhexyl sulfosuccinate/sodium dodecyl sulfate (2/1, w/w. Nanoparticles were characterized by X-ray diffraction, atomic absorption spectroscopy, and high-resolution transmission electron microscopy. In spite of the high-water/surfactant molar ratio and concentration of silver nitrate solution used in this study, characterizations demonstrated that nanoparticles were silver crystals (purity >99% with 8.6–8.8 nm in average diameter and 2.9–4.7 nm in standard deviation. It is proposed that slow dosing rate of aqueous solution of precipitating agent and the small molecular volume of toluene attenuated both particle aggregation and polydispersity widening. Experimental yield of silver nanoparticles obtained in this study was much higher than theoretical yields calculated from available data in the literature on preparation of silver nanoparticles in reverse microemulsions.

  15. High-level expression and purification of soluble bioactive recombinant human heparin-binding epidermal growth factor in Escherichia coli.

    Science.gov (United States)

    Khalili, Mostafa; Soleyman, Mohammad Reza; Baazm, Maryam; Beyer, Cordian

    2015-07-01

    Heparin-binding epidermal growth factor (HB-EGF) is a member of highly conserved superfamily of proteins that has potential mitogenic activity and stimulates differentiation and migration of various cell types. Since HB-EGF has three intra-molecular disulfide bonds, a high expression pattern of active HB-EGF in an E. coli expression system was not successfully established. The aim of this study was to increase production of soluble bioactive recombinant human HB-EGF in E. coli by modifying growth conditions and codon optimization. The open reading frame codons of human HB-EGF were optimized to achieve high level expression in E. coli. The optimized codon was amplified, cloned into plasmid pET-32a, and transformed into E. coli BL21 for further expression. The cultivation parameters (temperature and inducer) were optimized to produce a high yield of soluble HB-EGF. The fusion protein was purified by Nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. Amethylthiazole tetrazolium assay was used to evaluate the bioactivity of the produced recombinant protein. After codon optimization, the codon adaptation index (CAI) was increased from 0.255 in native gene to 0.829 using the optimized sequence. By lowering the temperature to 22°C and the inducer to 0.4 μM, we obtained 35% soluble expression of recombinant and biologically active human HB-EGF. Our data demonstrate that codon optimization increases the yield of HB-EGF in an E. coli expression system. Furthermore, the chosen modifications in cell culturing increase the solubility of recombinant human HB-EGF.

  16. Geothermal-brine modeling - prediction of mineral solubilities in natural waters: the Na-K-Mg-Ca-H-Cl-SO{sub 4}-OH-HCO{sub 3} CO{sub 3}-CO{sub 2}-H{sub 2}O system to high ionic strengths at 25{sup 0}C

    Energy Technology Data Exchange (ETDEWEB)

    Weare, J.H.

    1981-01-01

    The mineral solubility model of Harvie and Weare (1980) is extended to the eight component system, Na-K-Ca-Mg-H-Cl-SO{sub 4}-OH-HCO{sub 3}-CO{sub 3}-CO{sub 2}-H{sub 2}O at 25{sup 0}C to high concentrations. The model is based on the semi-empirical equations of Pitzer (1973) and co-workers for the thermodynamics of aqueous electrolyte solutions. The model is parameterized using many of the available isopiestic, electromotive force, and solubility data available for many of the subsystems. The predictive abilities of the model are demonstrated by comparison to experimental data in systems more complex than those used in parameterization. The essential features of a chemical model for aqueous electrolyte solutions and the relationship between pH and the equilibrium properties of a solution are discussed.

  17. SOLUBILITY OF URANIUM AND PLUTONIUM IN ALKALINE SAVANNAH RIVER SITE HIGH LEVEL WASTE SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    King, W.; Hobbs, D.; Wilmarth, B.; Edwards, T.

    2010-03-10

    Five actual Savannah River Site tank waste samples and three chemically-modified samples were tested to determine solubility limits for uranium and plutonium over a one year time period. Observed final uranium concentrations ranged from 7 mg U/L to 4.5 g U/L. Final plutonium concentrations ranged from 4 {micro}g Pu/L to 12 mg Pu/L. Actinide carbonate complexation is believed to result in the dramatic solubility increases observed for one sample over long time periods. Clarkeite, NaUO{sub 2}(O)OH {center_dot} H{sub 2}O, was found to be the dominant uranium solid phase in equilibrium with the waste supernate in most cases.

  18. Precipitation of neptunium dioxide from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, K E

    1999-12-01

    Tens of thousands of metric tons of highly radioactive, nuclear waste have been generated in the US. Currently, there is no treatment or disposal facility for these wastes. Of the radioactive elements in high-level nuclear waste, neptunium (Np) is of particular concern because it has a long half-life and may potentially be very mobile in groundwaters associated with a proposed underground disposal site at Yucca Mountain, Nevada. Aqueous Np concentrations observed in previous, short-term solubility experiments led to calculated potential doses exceeding proposed long-term regulatory limits. However, thermodynamic data for Np at 25 C showed that these observed aqueous Np concentrations were supersaturated with respect to crystalline NpO{sub 2}. It was hypothesized that NpO{sub 2} is the thermodynamically stable solid phase in aqueous solution, but it is slow to form in an aqueous solution of NpO{sub 2}{sup +} on the time scale of previous experiments. The precipitation of NpO{sub 2} would provide significantly lower aqueous Np concentrations leading to calculated doses below proposed regulatory limits. To test this hypothesis, solubility experiments were performed at elevated temperature to accelerate any slow precipitation kinetics. Ionic NpO{sub 2}{sup +} (aq) was introduced into very dilute aqueous solutions of NaCl with initial pH values ranging from 6 to 10. The reaction vessels were placed in an oven and allowed to react at 200 C until steady-state aqueous Np concentrations were observed. In all cases, aqueous Np concentrations decreased significantly from the initial value of 10{sup {minus}4} M. The solids that formed were analyzed by x-ray powder diffraction, x-ray absorption spectroscopy, and scanning electron microscopy. The solids were determined to be high-purity crystals of NpO{sub 2}. This is the first time that crystalline NpO{sub 2} has been observed to precipitate from NpO{sub 2}{sup +}(aq) in near-neutral aqueous solutions. The results obtained

  19. High-level soluble expression of Serratia marcescens H30 lipase in Escherichia coli.

    Science.gov (United States)

    Su, Erzheng; Xu, Jingjing; Wu, Xiangping

    2015-01-01

    Serratia marcescens lipase (SmL) is an important biocatalyst used to enantioselectively hydrolyze (±)-trans-3-(4-methoxyphynyl) glycidic acid methyl ester. However, the economically justified level recombinant soluble expression of SmL in Escherichia coli has not been established. Thus, fusion genes of lipase from S. marcescens H30 with different fusion tags were constructed and expressed in E. coli. The effects of fusion tags were revealed. A significant increase in recombinant lipase solubility showed that E. coli BL21 (DE3)/pET32a-SmL was a suitable choice for SmL production. To optimize the performance of recombinant SmL production, changes in culture medium compositions and induction conditions were systematically tested. Finally, the recombinant SmL activity and productivity reached approximately 23,000 U/L and 1,278 U/L/H in shake flasks, respectively. This value is the highest SmL activity attained by heterogeneous recombinant expression in E. coli. Lipase activity and productivity reached 19,650 U/L and 1,228 U/L/H, respectively, by scaling up SmL production in a 7.0 L fermenter. The existence of the Trx tag did not influence the chiral selectivity of recombinant SmL. These findings indicate a possibility for soluble and economical SmL expression in E. coli to meet industrial needs.

  20. Absorção de gordura, solubilidade e propriedades espumantes dos extratos hidrossolúveis desidratados de arroz e soja Fat absorption, solubility and whipping properties of dehydrated aqueous extracts of rice-soybean

    Directory of Open Access Journals (Sweden)

    Sin H. WANG

    2000-08-01

    Full Text Available Foram estudadas absorção de gordura (AG, índice de solubilidade em água (ISA e propriedades espumantes dos extratos hidrossolúveis desidratados elaborados com arroz e soja em diferentes proporções (100:0, 90:10, 80:20, 70:30, 60:40 e 50:50, com o objetivo de verificar a possibilidade de uso em produtos alimentícios. Os processos utilizados para a obtenção foram: maceração do arroz e da soja, desintegração, centrifugação, adição de ácido cítrico, fervura e secagem por atomização. Nas determinações, observou-se que houve um aumento na AG, no ISA e na sinérese de espuma, porém uma diminuição na expansão e no volume de espuma com o aumento das proporções de soja.Dehydrated aqueous extracts of rice-soybean at different proportions(100:0, 90:10, 80:20, 70:30, 60:40 e 50:50 were assessed for fat absorption (FA, water solubility index (WSI and whipping properties in order to verify their potential use as food ingredients. Dehydrated aqueous extract was manufactured by soaking, disintegration, centrifugation, addition of citric acid, boiling and spray-drying. The results indicated that increasing soybean proportions from 0 to 50% caused an increase in FA, WSI and foam syneresis, but a decrease in expansion and in volume of foam.

  1. Highly Conductive Graphene and Polyelectrolyte Multilayer Thin Films Produced From Aqueous Suspension.

    Science.gov (United States)

    Stevens, Bart; Guin, Tyler; Sarwar, Owais; John, Alyssa; Paton, Keith R; Coleman, Jonathan N; Grunlan, Jaime C

    2016-09-27

    Rapid, large-scale exfoliation of graphene in water has expanded its potential for use outside niche applications. This work focuses on utilizing aqueous graphene dispersions to form thin films using layer-by-layer processing, which is an effective method to produce large-area coatings from water-based solutions of polyelectrolytes. When layered with polyethyleneimine, graphene flakes stabilized with cholate are shown to be capable of producing films thinner than 100 nm. High surface coverage of graphene flakes results in electrical conductivity up to 5500 S m(-1) . With the relative ease of processing, the safe, cost effective nature of the ingredients, and the scalability of the deposition method, this system should be industrially attractive for producing thin conductive films for a variety of electronic and antistatic applications.

  2. High-Frequency Electron Paramagnetic Resonance Spectroscopy of Nitroxide-Functionalized Nanodiamonds in Aqueous Solution.

    Science.gov (United States)

    Akiel, R D; Stepanov, V; Takahashi, S

    2016-06-21

    Nanodiamond (ND) is an attractive class of nanomaterial for fluorescent labeling, magnetic sensing of biological molecules, and targeted drug delivery. Many of those applications require tethering of target biological molecules on the ND surface. Even though many approaches have been developed to attach macromolecules to the ND surface, it remains challenging to characterize dynamics of tethered molecule. Here, we show high-frequency electron paramagnetic resonance (HF EPR) spectroscopy of nitroxide-functionalized NDs. Nitroxide radical is a commonly used spin label to investigate dynamics of biological molecules. In the investigation, we developed a sample holder to overcome water absorption of HF microwave. Then, we demonstrated HF EPR spectroscopy of nitroxide-functionalized NDs in aqueous solution and showed clear spectral distinction of ND and nitroxide EPR signals. Moreover, through EPR spectral analysis, we investigate dynamics of nitroxide radicals on the ND surface. The demonstration sheds light on the use of HF EPR spectroscopy to investigate biological molecule-functionalized nanoparticles.

  3. Fabrication of silver nanoparticles by highly intense laser irradiation of aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takahiro; Magara, Hideyuki; Herbani, Yuliati; Sato, Shunichi [Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Sendai (Japan)

    2011-09-15

    Silver (Ag) nanoparticles were fabricated by highly intense femtosecond laser irradiation of aqueous solutions of silver nitrate (AgNO{sub 3}) with various concentrations. After irradiation, a broad absorption peak at around 420 nm originating from surface plasmon resonance of Ag nanoparticles was observed in 30 and 300 mM solutions. Transmission electron microscopy revealed that Ag nanoparticles produced in 300 mM AgNO{sub 3} solution had a typical size in the range of 2 to 20 nm and a mean size of 4 nm. The addition of 1.0 x 10{sup -2} wt% polyvinylpyrrolidone as a dispersant to the 300 mM solution caused a narrower particle size distribution as well as a narrower absorption peak width after the laser irradiation. As a result, Ag nanoparticles with a mean particle size of about 2 nm were fabricated. (orig.)

  4. Improving co-amorphous drug formulations by the addition of the highly water soluble amino acid proline

    DEFF Research Database (Denmark)

    Jensen, Katrine Birgitte Tarp; Löbmann, Korbinian; Rades, Thomas;

    2014-01-01

    by combining the model drug, naproxen (NAP), with an amino acid to physically stabilize the co-amorphous system (tryptophan, TRP, or arginine, ARG) and a second highly soluble amino acid (proline, PRO) for an additional improvement of the dissolution rate. Co-amorphous drug-amino acid blends were prepared......Co-amorphous drug amino acid mixtures were previously shown to be a promising approach to create physically stable amorphous systems with the improved dissolution properties of poorly water-soluble drugs. The aim of this work was to expand the co-amorphous drug amino acid mixture approach...... by ball milling and investigated for solid state characteristics, stability and the dissolution rate enhancement of NAP. All co-amorphous mixtures were stable at room temperature and 40 °C for a minimum of 84 days. PRO acted as a stabilizer for the co-amorphous system, including NAP–TRP, through enhancing...

  5. Highly loaded interactive mixtures for dry powder inhalers: prediction of the adhesion capacity using surface energy and solubility parameters.

    Science.gov (United States)

    Wagner, K G; Dowe, U; Zadnik, J

    2005-05-01

    In order to correlate drug adhesion properties of a highly loaded interactive mixture for the use in dry powder inhalers with the surface energy and to establish a link to the solubility parameter, surface free energy was detected for micronized substances (salbutamol sulfate, salbutamol base, theophylline and alpha-lactose monohydrate) using inverse gas chromatography (IGC). Interactive mixtures with coarse crystalline alpha-lactose monohydrate as a carrier were prepared at loading levels from 7.5 to 20% (w/w) and analyzed with respect to their adhesion capacity (CA) using the air jet sieving method. Solubility parameters were taken from literature or calculated. As a result the CA was independent of the drug load and correlated linearly with volume specific surface energy interaction (SEIv) values of the adherents (R2 = 0.98498). A link between SEIv and the size normalized solubility parameter (delta(tot)/d50) was found. Consequently, plotting delta(tot)/d50 versus CA resulted also in a strong linear relationship (R2 = 0.99140). Overall a powerful tool was established to judge and quantify adhesion properties of highly loaded interactive mixtures even for estimates in early preformulation at a time where just the molecular structure of the active ingredient is known.

  6. High-performance magnetic carbon materials in dye removal from aqueous solutions

    Science.gov (United States)

    Gao, Xiaoming; Zhang, Yu; Dai, Yuan; Fu, Feng

    2016-07-01

    To obtain a novel adsorbent with excellent adsorption capacity and convenient magnetic separation property, magnetic activated semi-coke was prepared by KOH activation method and further modified by FeCl3. The surface morphology, physical structure, chemical properties and textural characteristics of unmodified semi-coke, KOH-modified semi-coke and magnetic activated semi-coke were characterized by scanning electron microscopy, X-ray powder diffraction, N2 adsorption-desorption measurement, and electronic differential system. The adsorption characteristics of the magnetic activated semi-coke were explored for the removal of methyl orang (MO), methylene blue (MB), congo red (CR), acid fuchsin (AF), and rhodamine B (RB) from aqueous solution. The effects of adsorption parameters, including adsorbent dosage, pH and contact time, were investigated by comparing the adsorption properties of the magnetic activated semi-coke to RB. The result showed that the magnetic activated semi-coke displayed excellent dispersion, convenient separation and high adsorption capacity. The adsorption experiment data indicated that the pseudosecond order model and the Langmuir model could well explain the adsorption processes of RB on the magnetic activated semi-coke, and the maximum adsorption capacity (qm) was 526.32 mg/g. The values of thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicated that the adsorption process depended on the temperature of the aqueous phase, and it was spontaneous and exothermic in nature. As the addition of the magnetic activated semi-coke, the color of the solution significantly faded. Subsequently, fast aggregation of the magnetic activated semi-coke from their homogeneous dispersion in the presence of an external magnetic field could be happened. So, the magnetic activated semi-coke displayed excellent dispersion, convenient separation and high adsorption capacity.

  7. Highly stable layered double hydroxide colloids: a direct aqueous synthesis route from hybrid polyion complex micelles.

    Science.gov (United States)

    Layrac, Géraldine; Destarac, Mathias; Gérardin, Corine; Tichit, Didier

    2014-08-19

    Aqueous suspensions of highly stable Mg/Al layered double hydroxide (LDH) nanoparticles were obtained via a direct and fully colloidal route using asymmetric poly(acrylic acid)-b-poly(acrylamide) (PAA-b-PAM) double hydrophilic block copolymers (DHBCs) as growth and stabilizing agents. We showed that hybrid polyion complex (HPIC) micelles constituted of almost only Al(3+) were first formed when mixing solutions of Mg(2+) and Al(3+) cations and PAA3000-b-PAM10000 due to the preferential complexation of the trivalent cations. Then mineralization performed by progressive hydroxylation with NaOH transformed the simple DHBC/Al(3+) HPIC micelles into DHBC/aluminum hydroxide colloids, in which Mg(2+) ions were progressively introduced upon further hydroxylation leading to the Mg-Al LDH phase. The whole process of LDH formation occurred then within the confined environment of the aqueous complex colloids. The hydrodynamic diameter of the DHBC/LDH colloids could be controlled: it decreased from 530 nm down to 60 nm when the metal complexing ratio R (R = AA/(Mg + Al)) increased from 0.27 to 1. This was accompanied by a decrease of the average size of individual LDH particles as R increased (for example from 35 nm at R = 0.27 down to 17 nm at R = 0.33), together with a progressive favored intercalation of polyacrylate rather than chloride ions in the interlayer space of the LDH phase. The DHBC/LDH colloids have interesting properties for biomedical applications, that is, high colloidal stability as a function of time, stability in phosphate buffered saline solution, as well as the required size distribution for sterilization by filtration. Therefore, they could be used as colloidal drug delivery systems, especially for hydrosoluble negatively charged drugs.

  8. Improving Co-Amorphous Drug Formulations by the Addition of the Highly Water Soluble Amino Acid, Proline

    Directory of Open Access Journals (Sweden)

    Katrine Tarp Jensen

    2014-07-01

    Full Text Available Co-amorphous drug amino acid mixtures were previously shown to be a promising approach to create physically stable amorphous systems with the improved dissolution properties of poorly water-soluble drugs. The aim of this work was to expand the co-amorphous drug amino acid mixture approach by combining the model drug, naproxen (NAP, with an amino acid to physically stabilize the co-amorphous system (tryptophan, TRP, or arginine, ARG and a second highly soluble amino acid (proline, PRO for an additional improvement of the dissolution rate. Co-amorphous drug-amino acid blends were prepared by ball milling and investigated for solid state characteristics, stability and the dissolution rate enhancement of NAP. All co-amorphous mixtures were stable at room temperature and 40 °C for a minimum of 84 days. PRO acted as a stabilizer for the co-amorphous system, including NAP–TRP, through enhancing the molecular interactions in the form of hydrogen bonds between all three components in the mixture. A salt formation between the acidic drug, NAP, and the basic amino acid, ARG, was found in co-amorphous NAP–ARG. In comparison to crystalline NAP, binary NAP–TRP and NAP–ARG, it could be shown that the highly soluble amino acid, PRO, improved the dissolution rate of NAP from the ternary co-amorphous systems in combination with either TRP or ARG. In conclusion, both the solubility of the amino acid and potential interactions between the molecules are critical parameters to consider in the development of co-amorphous formulations.

  9. Coupling of highly explicit gas and aqueous chemistry mechanisms for use in 3-D

    Science.gov (United States)

    Ginnebaugh, Diana L.; Jacobson, Mark Z.

    2012-12-01

    This study discusses the coupling of a near-explicit gas-phase chemical mechanism with an extensive aqueous-phase mechanism in an accurate chemical solver designed for use in 3-D models. The gas and aqueous mechanisms and the solver used are the Master Chemical Mechanism (MCM 3.1), the Chemical Aqueous Phase Radical Mechanism (CAPRAM 3.0i), and the SMVGEAR II ordinary differential solver, respectively. The MCM has over 13,500 reactions and 4600 species, whereas CAPRAM treats aqueous chemistry among 390 species and 829 reactions (including 51 gas-to-aqueous phase reactions). SMVGEAR II is a sparse-matrix Gear solver that reduces the computation time significantly while maintaining any specified accuracy. MCM has been used previously with SMVGEAR II in 3-D, and computer timings here indicate that coupling MCM with CAPRAM in SMVGEAR II is also practical. Gas- and aqueous-phase species are coupled through time-dependent dissolutional growth and dissociation equations. This method is validated with a smaller mechanism against results from a previous model intercomparison. When the smaller mechanism is compared with the full MCM-CAPRAM mechanism, some concentrations are still similar but others differ due to the greater detail in chemistry. We also expand the mechanism to include gas-aqueous transfer of two acids, glycolic acid and glyoxylic acid, and modify the glyoxal Henry's law constant from recent measurements. The average glyoxal partitioning in the cloud changed from 67% aqueous-phase to 87% aqueous-phase with the modifications. The addition of gas-aqueous transfer reactions increased the average gas-phase percentage of glycolic acid to 19% and of glyoxylic acid to 16%. This full gas-phase and aqueous-phase chemistry module is a potentially useful tool for studying air pollution in a cloud or a fog.

  10. Dibutyl Phosphoric Acid Solubility in High-Acid, Uranium-Bearing Solutions at SRS

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, R.A.

    1998-10-02

    The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are approximately 6 g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with the dibutylphosphate ion (DBP) which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. Prior SRTC tests (WSRC-TR-98-00188) showed that U-DBP solids precipitate at concentrations potentially attainable during the storage of enriched uranium solutions. Furthermore, evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if the DBP concentration in the resulting solution exceeds 110 mg/L at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. As a follow-up to the earlier studies, SRTC studied the solubility limits for solutions containing acid concentrations above 0.5M HNO3. The data obtained in these tests reveals a shift to higher levels of DBP solubility above 0.5M HNO3 for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified a mixture of different molecular structures for the solids created. The analysis distinguished UO2(DBP)2 as the dominant compound present at low acid concentrations. As the acid concentration increases, the crystalline UO2(DBP)2 shows molecular substitutions and an increase in amorphous content. Further analysis by methods not available at SRS will be needed to better identify the specific compounds present. This data indicates that acidification prior to evaporation can be used to increase the margin of safety for the storage of the EUS solutions. Subsequent experimentation evaluated options

  11. Synthesis and properties of novel soluble poly(aryl amine ketone)s as high-performance polymers

    Institute of Scientific and Technical Information of China (English)

    CHANG GuanJun; TANG ShiZhen; LUO Xuan; WANG Qiang; XU Zhe; ZHANG Lin; LIN RunXiong

    2008-01-01

    A series of poly(aryl amine ketone)s have been obtained by the condensation polymerization of differ-ent aromatic dibromides with different primary aromatic diamines via palladium-catalyzed aryl amina-tion reaction. The structures of polymers are characterized by means of FT-IR, 1H NMR spectroscopy, and elemental analysis. The results show an agreement with the proposed structures. DSC and TG measurements show that polymers possess high glass transition temperature (Tg>170"C) and good thermal stability with high decomposition temperatures (To>450℃). These novel polymers also exhibit good mechanical behaviors and good solubility.

  12. Mineral Surface after Reaction with Aqueous Solution at High Temperatures and Pressures

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This work presents new experimental results on surface chemistry of reacting minerals and interface kinetics between mineral and aqueous solutions. These experiments were carried out using a flow reactor (packed bed reactor) of an open system as well as a continuous stirred tank reactor, CSTR. The authors measured reaction rates of such minerals as zeolite, albite and carbonate (rhodochrosite, dolomite) in various solutions, and tested corresponding mineral surface by using SEM, XPS, SIMS, etc. This paper mainly presents the experimental results of zeolite dissolution in water and in low pH solutions at room temperature, and dolomite dissolution at elevated temperatures. The results show that the release rates of Si, Al and Na of zeolite are different in most cases. The incongruent dissolution of zeolite is related to surface chemical modifications. The Na, Al and Si release rates for dissolution of albite and zeolite in water and various solutions were measured as a function of temperature, flow velocity, pH and solution composition in the reaction system. In most cases, dissolutions of both albite and zeolite are incongruent. Dissolution of dolomite is also incongruent in most cases and varied with T, pH, and nature of aqueous solutions. For dolomite dissolution, the release rates of Mg are less than those of Ca at high temperatures as T increases from 25 to 300° C. SIMS study indicates that the contents of Al, Na and Si in the leached layer of zeolite or albite surface, change with the distance from the surface, exhibiting a non-linear behaviour within a thickness range of 1000%. The distributions of Ca, Mg, Mn, H and Cl in the leached surface layer of carbonate have a non-linear behaviour too.

  13. Low Temperature Aqueous Solution-Processed ZnO and Polyethylenimine Ethoxylated Cathode Buffer Bilayer for High Performance Flexible Inverted Organic Solar Cells

    National Research Council Canada - National Science Library

    Hailong You; Junchi Zhang; Zeyulin Zhang; Chunfu Zhang; Zhenhua Lin; Jingjing Chang; Genquan Han; Jincheng Zhang; Gang Lu; Yue Hao

    2017-01-01

    High performance flexible inverted organic solar cells (OSCs) employing the low temperature cathode buffer bilayer combining the aqueous solution-processed ZnO and polyethylenimine ethoxylated (PEIE...

  14. Treatment of Aqueous Solutions

    NARCIS (Netherlands)

    Van Spronsen, J.; Witkamp, G.J.

    2013-01-01

    The invention is directed to a process for the recovery or removal of one or more crystallizable compounds from an aqueous solution containing, apart from the said crystallizable compounds, one or more organic or inorganic scale- forming or scale-inducing materials having a lower solubility in water

  15. Solubilidade de nitrogênio, dispersibilidade de proteína e propriedades emulsificantes dos extratos hidrossolúveis desidratados de arroz e soja Nitrogen solubility, protein dispersibility and emulsifying properties of dehydrated aqueous extracts of rice-soybean

    Directory of Open Access Journals (Sweden)

    Sin H. WANG

    2000-04-01

    Full Text Available Com o objetivo de verificar a possibilidade do uso dos extratos hidrossolúveis desidratados elaborados com arroz e soja em diferentes proporções (100:0, 90:10, 80:20, 70:30, 60:40 e 50:50% em produtos alimentícios, foram estudadas solubilidade e propriedades emulsificantes das misturas. Os processos utilizados para a obtenção foram: maceração do arroz e da soja, desintegração, centrifugação, adição de ácido cítrico, fervura e secagem por atomização. Através das análises, foi verificado que o aumento das proporções de soja (0 a 50% resultou, num aumento do nitrogênio solúvel em água, da atividade emulsificante e da estabilidade de emulsão, bem como numa diminuição do índice de solubilidade de nitrogênio e do índice de dispersibilidade de proteína. Contudo, a proteína dispersível em água aumentou até um máximo na proporção de 10% de soja, além do qual, diminuiu com o aumento das proporções de soja (10 a 50%. Portanto, os extratos hidrossolúveis desidratados das misturas de arroz e soja com 10, 20 e 30% de soja, são recomendados para o uso em produtos cárneos, de confeitaria e de chocolataria, sopas, molhos, cremes e bebidas, enquanto que aqueles com 40 e 50% de soja, são considerados mais adequados para uso como extensores de carne, queijos processados e maioneses.Dehydrated aqueous extracts of rice-soybean at different proportions (100:0, 90:10, 80:20, 70:30, 60:40 and 50:50% were assessed for nitrogen solubility index (NSI, protein dispersibility index (PDI, emulsifying activity (EA and emulsion stability (ES in order to verify their potential use as food ingredients. Dehydrated aqueous extracts was manufactured by soaking, disintegration, centrifugation, addition of citric acid, boiling and spray-drying. The results indicated that increasing soybean proportion from 0 to 50% showed an increase in the soluble nitrogen in water, EA and ES, and a decrease in the NSI and PDI. However, the dispersible

  16. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jun-Ho; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng, E-mail: mcho@korea.ac.kr [Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 136-713 (Korea, Republic of); Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Heejae; Kim, Seongheun [Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of)

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O—D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O—D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O—D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O—D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O—D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O—D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O—D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O—D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O—D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O—D stretch mode is shown to be important and the asymmetric line shapes of the O—D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We

  17. High-Yield Production of Levulinic Acid from Pretreated Cow Dung in Dilute Acid Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Jialei Su

    2017-02-01

    Full Text Available Agricultural waste cow dung was used as feedstock for the production of a high value–added chemical levulinic acid (LA in dilute acid aqueous solutions. A high LA yield of 338.9 g/kg was obtained from the pretreated cow dung, which was much higher than that obtained from the crude cow dung (135 g/kg, mainly attributed to the breakage of the lignin fraction in the lignocellulose structure of the cow dung by potassium hydroxide (KOH pretreatment, and thus enhanced the accessibility of cow dung to the acid sites in the catalytic reaction. Meanwhile, another value-added chemical formic acid could be obtained with a yield of ca. 160 g/kg in the process, implying a total production of ca. 500 g/kg yield for LA and formic acid from the pretreated cow dung with the proposed process. The developed process was shown to be tolerant to high initial substrate loading with a satisfied LA yield. This work provides a promising strategy for the value-increment utilization of liglocellulosic agricultural residues.

  18. Aqueous processing of U-10Mo scrap for high performance research reactor fuel

    Science.gov (United States)

    Youker, Amanda J.; Stepinski, Dominique C.; Maggos, Laura E.; Bakel, Allen J.; Vandegrift, George F.

    2012-08-01

    The Global Threat Reduction Initiative (GTRI) Conversion program, which is part of the US government's National Nuclear Security Administration (NNSA), supports the conversion of civilian use of highly enriched uranium (HEU) to low enriched uranium (LEU) for reactor fuel and targets. The reason for conversion is to eliminate the use of any material that may pose a threat to the United States or other foreign countries. High performance research reactors (HPRRs) cannot make the conversion to a standard LEU fuel because they require a more dense fuel to meet their performance requirements. As a result, a more dense fuel consisting of a monolithic uranium-molybdenum alloy containing 10% (w/w) Mo with Al cladding and a Zr bonding-layer is being considered. Significant losses are expected in the fabrication of this fuel, so a means to recycle the scrap pieces is needed. Argonne National Laboratory has developed an aqueous-processing flowsheet for scrap recovery in the fuel fabrication process for high-density LEU-monolithic fuel based on data found in the literature. Experiments have been performed to investigate dissolution conditions for solutions containing approximately 20 g-U/L and 50 g-U/L with and without Fe(NO3)3. HNO3 and HF concentrations have been optimized for timely dissolution of the fuel scrap and prevention of the formation of the U-Zr2 intermetallic, explosive complex, while meeting the requirements needed for further processing.

  19. The electrochemical fluorination of polymeric materials for high energy density aqueous and non-aqueous battery and fuel cell separators

    Science.gov (United States)

    Liu, C. C.

    1983-01-01

    A computerized system was established and the electrochemical fluorination of trichloroethylene, polyacrylic acid and polyvinyl alcohol in anhydrous hydrogen fluoride was attempted. Both solid substrates as well as membranes were used. Some difficulties were found in handling and analyzing the solid substrates and membranes. Further studies are needed in this area. A microprocessor aided electrochemical fluorination system capable of obtaining highly reproducible experimental results was established.

  20. Stearic acid and high molecular weight PEO as matrix for the highly water soluble metoprolol tartrate in continuous twin-screw melt granulation

    OpenAIRE

    Monteyne, Tinne; Adriaensens, Peter; Brouckaert, Davinia; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-01-01

    Granules with release-sustaining properties were developed by twin screw hot melt granulation (HMG) using a combination of stearic acid (SA) and high molecular weight polyethylene oxide (PEO) as matrix for a highly water soluble model drug, metoprolol tartrate (MPT). Earlier studies demonstrated that mixing molten SA and PEO resulted in hydrogen bond formation between hydroxyl groups of fatty acid molecules and ether groups in PEO chains. These molecular interactions might be beneficial in or...

  1. Flexible asymmetric supercapacitors with high energy and high power density in aqueous electrolytes.

    Science.gov (United States)

    Cheng, Yingwen; Zhang, Hongbo; Lu, Songtao; Varanasi, Chakrapani V; Liu, Jie

    2013-02-07

    Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO(2), activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s(-1) to 500 mV s(-1). Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg(-1)) under high power density (7.8 kW kg(-1)) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required.

  2. Post-treatment-free synthesis of highly mesoporous carbon for high-performance supercapacitor in aqueous electrolytes

    Science.gov (United States)

    Li, Wenqi; Liu, Simin; Pan, Ning; Zeng, Fanjun; Liu, Yingliang; Zheng, Mingtao; Liang, Yeru

    2017-07-01

    Exploring well-defined pore structure with high porosity has been a long-pursued goal for the development of porous carbon as high-performance supercapacitor electrodes. The pursuit of high surface area while maintaining uniform pore size remains a formidable challenge because their current template-directed synthetic processes are quite complex and time consuming. Here, we report herein a facile and post-treatment-free approach for synthesis of carbon materials with simultaneously high surface area and uniform mesopore size. The key to this preparation strategy is utilization of polytetrafluoroethylene that can in-situ generate hydrofluoric acid to etch out the silica templates during carbonization process. This strategy not only reduces synthesis procedure by combining post-silica-removal and carbonization in a single step, but also eliminates the direct usage of hazardous hydrofluoric acid or corrosive sodium hydroxide. The as-synthesized disordered mesoporous carbon presents higher Langmuir surface area (3257 m2 g-1), Brunauer-Emmett-Teller surface area (2302 m2 g-1) and mesopore rate (99.6%) when compared to traditional mesoporous carbon. With combination of high surface area and uniform mesopore size, the mesoporous carbon exhibits attractive capacitive properties in aqueous electrolytes, including large capacitance of 201 F g-1, high energy density of 28.3 Wh kg-1 and excellent cycling stability.

  3. High-performance magnetic carbon materials in dye removal from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Xiaoming, E-mail: dawn1026@163.com; Zhang, Yu; Dai, Yuan; Fu, Feng, E-mail: yadxfufeng@126.com

    2016-07-15

    To obtain a novel adsorbent with excellent adsorption capacity and convenient magnetic separation property, magnetic activated semi-coke was prepared by KOH activation method and further modified by FeCl{sub 3}. The surface morphology, physical structure, chemical properties and textural characteristics of unmodified semi-coke, KOH-modified semi-coke and magnetic activated semi-coke were characterized by scanning electron microscopy, X-ray powder diffraction, N{sub 2} adsorption-desorption measurement, and electronic differential system. The adsorption characteristics of the magnetic activated semi-coke were explored for the removal of methyl orang (MO), methylene blue (MB), congo red (CR), acid fuchsin (AF), and rhodamine B (RB) from aqueous solution. The effects of adsorption parameters, including adsorbent dosage, pH and contact time, were investigated by comparing the adsorption properties of the magnetic activated semi-coke to RB. The result showed that the magnetic activated semi-coke displayed excellent dispersion, convenient separation and high adsorption capacity. The adsorption experiment data indicated that the pseudosecond order model and the Langmuir model could well explain the adsorption processes of RB on the magnetic activated semi-coke, and the maximum adsorption capacity (q{sub m}) was 526.32 mg/g. The values of thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicated that the adsorption process depended on the temperature of the aqueous phase, and it was spontaneous and exothermic in nature. As the addition of the magnetic activated semi-coke, the color of the solution significantly faded. Subsequently, fast aggregation of the magnetic activated semi-coke from their homogeneous dispersion in the presence of an external magnetic field could be happened. So, the magnetic activated semi-coke displayed excellent dispersion, convenient separation and high adsorption capacity. - Graphical abstract: As the addition of the magnetic activated semi

  4. Investigation into the temporal stability of aqueous standard solutions of psilocin and psilocybin using high performance liquid chromatography.

    Science.gov (United States)

    Anastos, N; Barnett, N W; Pfeffer, F M; Lewis, S W

    2006-01-01

    This paper reports an investigation into the temporal stability of aqueous solutions of psilocin and psilocybin reference drug standards over a period of fourteen days. This study was performed using high performance liquid chromatography utilising a (95:5% v/v) methanol: 10 mM ammonium formate, pH 3.5 mobile phase and absorption detection at 269 nm. It was found that the exclusion of light significantly prolonged the useful life of standards, with aqueous solutions of both psilocin and psilocybin being stable over a period of seven days.

  5. Bromfenac ophthalmic solution 0.09 %: human aqueous humor concentration detected by high-performance liquid chromatography.

    Science.gov (United States)

    Macrì, Angelo; Vagge, Aldo; Salis, Annalisa; Fucile, Carmen; Marini, Valeria; Martelli, Antonietta; Giuffrida, Sebastiano; Iester, Michele; Damonte, Gianluca; Mattioli, Francesca

    2017-04-01

    The purpose of this study was to evaluate the aqueous humor concentrations of bromfenac ophthalmic solution 0.09 % in patients undergoing phacoemulsification. Patients requiring cataract extraction received one drop (50 µL) of bromfenac 0.09 % solution in the eye to be operated, before bedtime the day before surgery or the morning of the surgery. The last administration was recorded. At the time of paracentesis, an aqueous humor sample was collected with a 30-gauge needle attached to a TB syringe and was later analyzed by high-performance liquid chromatography for drug concentration. 188 treated volunteers and 48 control, untreated, subjects were included in the study. The mean aqueous concentration of bromfenac in the treated group was 37.60 ± 68.86 and 0 nM (nmol/L) in the control group (p humor up to about 12 h after instillation.

  6. The effect of sulfide dissolved in silicate melts on enhancing the solubility of the Highly Siderophile Elements

    Science.gov (United States)

    O'Neill, H. S.

    2015-12-01

    There are large inconsistencies among experimental studies of Highly Siderophile Element (HSE) partitioning relations between silicates and metal or sulfide phases, which has usually been attributed to "micronuggets", a general term for sub-optical (approximately HSE sulfide-melt/silicate-melt partition coefficients, where results range over several orders of magnitude. Moreover, nearly all the reported results of directly determined sulfide-melt/silicate-melt partition coefficients are considerably lower than values calculated by combining metal/silicate-melt with metal/sulfide-melt partition coefficients. This discrepancy has been attributed to large effects of S dissolved as sulfide in the silicate melts on HSE solubilities. As such large effects are not expected from the thermodynamic modeling of sulfide solubilities in silicate melts, it has been proposed that HSEs dissolve in sulfide-containing silicate melts by forming HSE-S complexes. This idea has been tested by experiments that compare the solubilities of Ir, Re and Ru in a high-TiO2 silicate melt both with and without dissolved sulfide at 1400 to 1600ºC at atmospheric pressure. The high TiO2 suppresses micronuggets. Experiments were analysed by LA-ICP-MS, with detection limits approaching 2 ppb. For Ir, the results show that at fO2 low enough to enable measurable sulfide in the melt, the presence of the sulfide just raises the level of dissolved Ir above detection limits. These results suggest a fairly large influence of the sulfide, but are not quantitative. By contrast, the experiments on Ru and Re clearly show only a modest effect of dissolved sulfide.

  7. Solubilities of CO2 in some glycol ethers under high pressure by experimental determination and correlation☆

    Institute of Scientific and Technical Information of China (English)

    Wei Wang; Zhi Yun; Zhigang Tang; Xia Gui

    2016-01-01

    The binary vapor–liquid equilibrium data of CO2 in diethylene glycol (monomethyl, monoethyl, monobutyl, di-methyl, diethyl, dibutyl) ether were determined from 288.15 to 318.15 K at pressure up to 6 MPa based on the constant-volume method. It was found by contrast that the ether group in solvents can promote the CO2 absorp-tion, but the hydroxyl group will inhibit the CO2 absorption. Furthermore, the solubilities of CO2 showed an up-ward trend with the increasing molecular lengths of absorbents. The experimental data were also correlated with a modified Patel–Teja equation of state (PT EOS) combined with the traditional van der Waals one-fluid mixing rules and the results showed a satisfactory agreement between the model and the experimental data.

  8. Aqueous solution route to high-aspect-ratio zinc oxide nanostructures on indium tin oxide substrates.

    Science.gov (United States)

    Ku, Chen-Hao; Wu, Jih-Jen

    2006-07-06

    High-aspect-ratio ZnO nanowires and nanotubes are formed on indium tin oxide (ITO) substrates using a three-step route at low temperatures. The three steps, including successive ionic layer absorption and reaction (SILAR) deposition of the ZnO seed layer, hydrothermal annealing of the seed layer, and chemical bath deposition (CBD) of the one-dimensional (1D) ZnO nanostructures, are all conducted in aqueous solutions at temperatures below 120 degrees C. Both the hydrothermal annealing of the SILAR seed layer and the low-concentration precursor solution employed in the CBD process are crucial in order to synthesize the uniform and high-aspect-ratio ZnO nanostructures on the ITO substrate. TEM analyses reveal that both the nanowire and the nanotube possess the single-crystal structure and are grown along [001] direction. Room-temperature cathodoluminescence spectrum of the 1D ZnO nanostructures shows a sharp ultraviolet emission at 375 nm and a broad green-band emission.

  9. Ionic liquids modified graphene oxide composites: a high efficient adsorbent for phthalates from aqueous solution

    Science.gov (United States)

    Zhou, Xinguang; Zhang, Yinglu; Huang, Zuteng; Lu, Dingkun; Zhu, Anwei; Shi, Guoyue

    2016-12-01

    In 2015, more than 30% of erasers were found to contain a PAE content that exceeded the 0.1% limit established by the Quality and Technology Supervision Bureau of Jiangsu Province in China. Thus, strengthening the supervision and regulation of the PAE content in foods and supplies, in particular, remains necessary. Graphene oxide (GO) and its composites have drawn great interests as promising adsorbents for polar and nonpolar compounds. However, GO-based adsorbents are typically restricted by the difficult separation after treatment because of the high pressure in filtration and low density in centrifugation. Herein, a series of novel ionic liquids modified graphene oxide composites (GO-ILs) were prepared as adsorbents for phthalates (PAEs) in eraser samples, which overcame the conventional drawbacks. These novel composites have a combination of the high surface area of graphene oxide and the tunability of the ionic liquids. It is expected that the GO-ILs composites can be used as efficient adsorbents for PAEs from aqueous solution. This work also demonstrated a new technique for GO-based materials applied in sample preparation.

  10. Films of chitin, chitosan and cellulose obtained from aqueous suspension treated by irradiation of high intensity ultrasound; Filmes de quitina, quitosana e celullose de sisal obtidos a partir de suspensoes aquosas tratadas com irradiacao de ultrassom de alta intensidade

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Erika V.R.; Mariano, Mario S.; Campana-Filho, Sergio P., E-mail: erikavi@iqsc.usp.br [Universidade de Sao Paulo (IQSC/USP), Instituto de Quimica de Sao Carlos, Sao Carlos, SP (Brazil)

    2011-07-01

    Films of chitin, chitin/chitosan and chitin/sisal cellulose were obtained by casting their aqueous suspensions previously treated with irradiation of high intensity ultrasound. The films were characterized for surface morphology by scanning electron microscopy and it is possible notice that the films containing chitosan are much more homogeneous. The thermal behavior of the films was evaluated by dynamic mechanical thermal analysis, differential scanning calorimetry, and thermogravimetric analysis and revealing similarity in comparison with the thermal behavior of polysaccharide isolated. The tensile strength was determined and the film containing chitosan showed the best result when compared to other films. The crystallinity index of the films analyzed by X-ray diffraction showed that the films are amorphous material. The analysis by infrared spectroscopy showed that treatment of aqueous suspensions of polysaccharides with irradiation of high intensity ultrasound did not change the chemical structure of polymers. The crystallinity index was determined by X-ray diffraction, revealing that the films are amorphous materials. The results of this study indicate the possibility of processing of chitin, chitosan and cellulose, polysaccharides whose solubilities are limited to a few solvent systems, by treating their aqueous suspensions with high intensity ultrasound. (author)

  11. Evaluation and Prediction of Henry’s Law Constants and Aqueous Solubilities for Solvents and Hydrocarbon Fuel Components. Volume 2. Experimental Henry’s Law Data

    Science.gov (United States)

    1987-09-01

    Redlich - Kwong Equation of State," J. Eng. Sci., Vol. 27:1197-1203. 1972. Staverman, A. J., ’.The Entropy of High Polymer Solutions. Generalization of...NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION (If applicable ) Research Triangle Institute HQ AFESC/RDVW 6c...page 61). The techniques were examined.to determine their applicability to environmental systems and their predictive capacity for unmeasured

  12. Size controlled sonochemical synthesis of highly crystalline superparamagnetic Mn–Zn ferrite nanoparticles in aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Mohamed [Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-873 Daegu (Korea, Republic of); Ceramics Department, National Research Centre, El-Bohous Street, 12622 Cairo (Egypt); Torati, Sri Ramulu [Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-873 Daegu (Korea, Republic of); Rao, B. Parvatheeswara [Department of Physics, Andhra University, Visakhapatnam 530003 (India); Abdel-Hamed, M.O. [Physics Department, Faculty of Science, El-Minia University (Egypt); Kim, CheolGi, E-mail: cgkim@dgist.ac.kr [Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-873 Daegu (Korea, Republic of)

    2015-09-25

    Highlights: • Mn–Zn ferrite NPs were synthesized by two different methods are polyol and sonochemical. • The sonochemical method produced NPs with high crystallinity than polyol method. • The ferrite samples synthesized by sonochemical method showed high magnetization values and superparamagnetic properties. • XRD, TEM, EDS, TGA, FTIR, and VSM techniques used to characterize the samples. - Abstract: Monodisperse Mn{sub x}Zn{sub 1−x}Fe{sub 2}O{sub 4} (x = 0.2, 0.5 and 0.8) nanoparticles have been synthesized using two different routes namely sonochemical and polyol methods, and the shape and size along with physiochemical properties of the nanoparticles were compared in detail. In both the routes, the synthesis was performed in a single reaction without the use of any surfactant and deoxygenated conditions. The reaction kinetics and surface adsorption characteristics of nanoparticles were observed by thermogravimetric analysis and Fourier transform infrared spectroscopy measurements. X-ray diffraction patterns confirmed the formation of a pure ferrite phase with cubic spinel structure, and the patterns further clearly indicate that the sonochemical method produces highly crystalline particles without any post calcination reaction, comparing with the polyol process. Transmission electron microscopy results reveal that the nanoparticles synthesized by polyol method are mostly aggregated and spherical in nature whereas the nanoparticles produced by sonochemical method are monodisperse large particles with cubic like shapes. The overall studies demonstrated that the sonochemical method is facile, reliable, rapid and very attractive for the aqueous synthesis of highly crystalline and high magnetic moment (84.5 emu/g) monodisperse superparamagnetic Mn–Zn ferrite nanoparticles which considered as potential materials for various applications.

  13. Prediction of water solubilities for selected PCDDs/PCCDFs with COSMO-RS model

    Energy Technology Data Exchange (ETDEWEB)

    Oleszek-Kudlak, S.; Grabda, M.; Shibata, E.; Nakamura, T. [Inst. of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku Univ., Sendai (Japan); Rosik-Dulewska, C. [Inst. of Environmental Engineering of the Polish Academy of Sciences, Zabrze (Poland)

    2004-09-15

    Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are well identified contaminants ubiquitous in the environment. Of the various parameters that affect the fate and behavior of environmental organic compounds, water solubility is one of the most important. However, when we are studying the aqueous behavior of organic chemicals, we should also take into consideration and evaluate several parameters (temperature, salinity, dissolved organic matter) influencing their solubility. Among the 210 congeners (mono- to octa-chlorinated) of PCDDs and PCDFs, water solubility values are available for a few congeners only. The reported aqueous solubilities of PCDDs and PCDFs are often scattered, despite most of them having been measured by the generator column method, recognized as the most accurate for the determination of the water solubility of hydrophobic organic chemicals. These discrepancies reflect an important problem associated with difficulties in the preparation of the saturated solution and in the analytical measurements, particularly of compounds with a solubility below 1 ppb. In practice, the high cost of the experimental determinations also limits the field of research. In recent years, investigators have developed a number of calculational methods to predict the water solubility of organic chemicals. One of them is the Conductor-like Screening Model for Real Solvents (COSMO-RS) introduced by Klamt et al. This model was successfully used for finding the solubilities of chlorobenzenes (ClBZs) at a wider range of temperatures (from 5 to 60 C) and in a salty environment. In this study, we have applied COSMO-RS to determine the aqueous solubilities of 19 PCDDs/ PCDFs at 25 C. Additionally, we measured the solubilities of 7 PCDDs/PCDFs using the generator column method at 25 C. We used these data and those available from the literature to estimate the accuracy of the COSMO-RS calculations.

  14. Evaluation of chitosan–anionic polymers based tablets for extended-release of highly water-soluble drugs

    Directory of Open Access Journals (Sweden)

    Yang Shao

    2015-02-01

    Full Text Available The objective of this study is to develop chitosan–anionic polymers based extended-release tablets and test the feasibility of using this system for the sustained release of highly water-soluble drugs with high drug loading. Here, the combination of sodium valproate (VPS and valproic acid (VPA were chosen as the model drugs. Anionic polymers studied include xanthan gum (XG, carrageenan (CG, sodium carboxymethyl cellulose (CMC-Na and sodium alginate (SA. The tablets were prepared by wet granulation method. In vitro drug release was carried out under simulated gastrointestinal condition. Drug release mechanism was studied. Compared with single polymers, chitosan–anionic polymers based system caused a further slowdown of drug release rate. Among them, CS–xanthan gum matrix system exhibited the best extended-release behavior and could extend drug release for up to 24 h. Differential scanning calorimetry (DSC and Fourier transform infrared spectroscopy (FTIR studies demonstrated that polyelectrolyte complexes (PECs were formed on the tablet surface, which played an important role on retarding erosion and swelling of the matrix in the later stage. In conclusion, this study demonstrated that it is possible to develop highly water-soluble drugs loaded extended-release tablets using chitosan–anionic polymers based system.

  15. Double-walled microspheres for the sustained release of a highly water soluble drug: characterization and irradiation studies.

    Science.gov (United States)

    Lee, Teng Huar; Wang, Jianjun; Wang, Chi-Hwa

    2002-10-30

    Composite double-walled microspheres with biodegradable poly(L-lactic acid) (PLLA) shells and poly(D,L-lactic-co-glycolic acid) (PLGA) cores were fabricated with highly water-soluble etanidazole entrapped within the core as solid crystals. This paper discusses the characterization, in vitro release and the effects of irradiation on this class of microsphere. Through the variation of polymer mass ratios, predictable shell and core dimensions could be fabricated and used to regulate the release rates. A direct and simple method was devised to determine the composition of the shell and core polymer based on the different solubilities of the polymer pair in ethyl acetate. A distribution theory based on solubility parameter explains why highly hydrophilic etanidazole has the tendency to be distributed consistently to the more hydrophilic polymer. Release profiles for normal double-walled samples have about 80% of drug released over 10 days after the initial time lag, while for irradiated double-walled samples, the sustained release lasted for more than 3 weeks. Although sustained release was short of the desired 6-8 weeks required for therapy, a low initial burst of less than 5% and time lags that can be manipulated, allows for administration of these microspheres together with traditional ones to generate pulsatile or new type of releases. The effects of irradiation were also investigated to determine the suitability of these double-walled microspheres as delivery devices to be used in conjunction with radiotherapy. Typical therapeutic dosage of 50 Gy was found to be too mild to have noticeable effects on the polymer and its release profiles, while, sterilization dosages of 25 kGy, lowered the glass transition temperatures and crystalline melting point, indirectly indicating a decrease in molecular weight. This accelerated degradation of the polymer, hence releasing the drug.

  16. A Flow-Through High-Pressure Electrical Conductance Cell for Determining of Ion Association of Aqueous Electrolyte Solutions at High Temperature and Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, H.; Ho, P.C.; Palmer, D.A.; Wood, R.H.

    1999-09-12

    A flow-through high-pressure electrical conductance cell was designed and constructed to measure limiting molar conductances and ion association constants of dilute aqueous solutions with high precision at high temperatures and pressures. The basic concept of the cell employs the principle developed at the University of Delaware in 1995, but overall targets higher temperatures (to 600 C) and pressures (to 300 MPa). At present the cell has been tested by measuring aqueous NaCl and LiOH solutions (10{sup {minus}3} to 10{sup {minus}5} mol.kg{sup {minus}1}) to 405 C and 33 MPa with good results.

  17. Estimation of Aqueous Solubility (-lgSw) of All Polychlorinated Biphenyl (PCB) Congeners by Density Functional Theory and Position of Cl Substitution (NPCS) Method

    Institute of Scientific and Technical Information of China (English)

    WEI Xiao-Yan; GE Zhi-Gang; WANG Zun-Yao; XU Jiao

    2007-01-01

    Optimization calculations of 209 polychlorinated biphenyls (PCBs) were carried out at the B3LYP/6-31G* level. It was found that there is significant correlation between the Cl substitution position and some structural parameters. Consequently, Cl substitution positions were taken as theoretical descriptors to establish a novel QSPR model for predicting -lgSw of all PCB congeners. The model achieved in this work contains four variables, of which r2 = 0.9527, q2 = 0.9490 and SD = 0.25 with large t values. In addition, the variation inflation factors (VIFs) of variables in this model are all less than 5.0, suggesting high accuracy of the -lgSw predicting model. And the results of cross-validation test and method validation also show that the model exhibits optimum stability and better predictive capability than that from the AM1 method.

  18. Antidiabetic, antioxidant and anti inflammatory properties of water and n-butanol soluble extracts from Saharian Anvillea radiata in high-fat-diet fed mice.

    Science.gov (United States)

    Kandouli, Chouaib; Cassien, Mathieu; Mercier, Anne; Delehedde, Caroline; Ricquebourg, Emilie; Stocker, Pierre; Mekaouche, Mourad; Leulmi, Zineb; Mechakra, Aicha; Thétiot-Laurent, Sophie; Culcasi, Marcel; Pietri, Sylvia

    2017-07-31

    According to Saharian traditional medicine, Anvillea radiata Coss. & Dur. (Asteraceae) has been valued for treating a variety of ailments such as gastro-intestinal, liver and pulmonary diseases, and has gained awareness for its beneficial effect on postprandial hyperglycemia. However, to best of our knowledge, no detailed study of the antidiabetic curative effects of this plant has been conducted yet. To determine the hypoglycemic and antidiabetic effect of dietary supplementation with Anvillea radiata extracts on high-fat-diet (HFD)-induced obesity and insulin resistance in C57BL/6J mice in relation with antioxidant, anti-inflammatory, pancreatic beta-cells and skeletal muscle protection, and digestive enzyme inhibiting properties. Six extracts (water soluble and organic) from aerial parts of the plant were analyzed phytochemically (total phenolic and flavonoid content) and screened for in vitro superoxide (by chemiluminescence) and hydroxyl radical (by electron paramagnetic resonance spin-trapping) scavenging, antioxidant (DPPH, TRAP and ORAC assays), xanthine oxidase, metal chelating, α-amylase and α-glucosidase inhibitory property, and protective effects on copper-induced lipoprotein oxidation. Then selected hydroalcoholic and aqueous extracts were assessed for toxicity in normal human lung fibroblasts and A549 cancer cells using FMCA and MTT assays. Two water-soluble extracts having the best overall properties were assessed for their (i) protective effect at 1-15µg/mL on metabolic activity of rat insulinoma-derived INS-1 cells exposed to hyperglycemic medium, and (ii) acute hypoglycemic effect on 16-weeks HFD-induced diabetic mice. Then diabetic mice were administered HFD supplemented by extracts (up to 150mg/kg/day) for 12 additional weeks using standard diet as control and the antidiabetic drug, metformin (150mg/kg), as positive control. Then the antidiabetic, anti-inflammatory and antioxidant activity of extracts were determined. Of the highly efficient

  19. Reduction of highly concentrated phosphate from aqueous solution using pectin-nanoscale zerovalent iron (PNZVI).

    Science.gov (United States)

    Wang, Hongyu; Zou, Zhuocheng; Xiao, Xuelian; Chen, Dan; Yang, Kai

    2016-01-01

    Pectin-nanoscale zerovalent iron (PNZVI) has been studied as an effective phosphate adsorption material to remove highly concentrated phosphate from aqueous solution. Batch phosphate removal and equilibrium experiments were conducted in order to evaluate the effects of environmental factors such as pH, coexisting anions and ionic strengths on phosphate removal by PNZVI. The scanning electron microscope images of nanoscale zerovalent iron (NZVI) and PNZVI demonstrated that PNZVI exhibited larger specific surface areas than NZVI so that PNZVI had higher phosphate removal efficiency than NZVI. Equilibrium experiments showed that phosphate adsorption by PNZVI was well fitted with the Freundlich and Langmuir models. In addition, the maximum adsorption capacity reached 277.38 mgP/gPNZVI. The ionic strengths and common anions showed no significant effects on the process of phosphate adsorption by PNZVI. The phosphate removal efficiency increased to a peak value with pH increased from 2.0 to 5.0, then decreased with pH further increased from 5.0 to 10.0. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses of PNZVI and P-loaded PNZVI indicated that adsorption, rather than redox reaction, was the dominant mechanism for the removal of phosphate by PNZVI.

  20. Preparation and characterization of aqueous dispersions of high amylose starch and conjugated linoleic acid complex.

    Science.gov (United States)

    Seo, Tae-Rang; Kim, Hee-Young; Lim, Seung-Taik

    2016-11-15

    Crystalline starch-CLA complexes were prepared by blending an alcoholic solution of conjugated linoleic acid (CLA) in an aqueous high-amylose maize starch dispersion. Recovery yield of CLA in the precipitates obtained by centrifuging the dispersion was dependent on reaction conditions such as temperature, time and pH. The CLA recovery reached a maximum when the reaction was performed at 90°C for 6h at neutral pH, with 67.7% of the initial CLA being co-precipitated with starch. The precipitates contained amylose-CLA complex exhibiting a V6I-type crystalline structure under X-ray diffraction analysis and a type II polymorph under DSC analysis. Ultrasonic treatment for the re-dispersed starch-CLA complex in water resulted in the reduction of hydrodynamic diameter of the complex particles to 201.5nm. The dispersion exhibited a zeta potential of -27.0mV and remained stable in an ambient storage without forming precipitates for more than 4weeks. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Synthesis of Highly Emissive CdSe Quantum Dots by Aqueous Precipitation Method

    Directory of Open Access Journals (Sweden)

    Bing Gao

    2013-01-01

    Full Text Available CdSe quantum dots (QDs with high quantum yield (QY up to 76.57% are synthesized using the aqueous precipitation method. With the control of SeSO32- concentration in Se precursor, the nucleation speed and concentration of CdSe QDs are increased. The mass of obtained Cd2+ and Se2+ in nanocrystal is measured by inductively coupled plasma atomic emission spectrometry (ICP-AES. XRD and HRTEM are used to identify the crystal phase and morphology of the products which are pure CdSe crystals in the cubic zinc blende phase and uniformly dispersed in the solution with the size between 2 nm and 2.3 nm. Results demonstrate that the emission wavelength of CdSe QDs is 500 nm~560 nm along with the increased temperature 50°C~90°C and prolonged time 5 min~25 min.

  2. High cycling stability of zinc-anode/conducting polymer rechargeable battery with non-aqueous electrolyte

    Science.gov (United States)

    Guerfi, A.; Trottier, J.; Boyano, I.; De Meatza, I.; Blazquez, J. A.; Brewer, S.; Ryder, K. S.; Vijh, A.; Zaghib, K.

    2014-02-01

    A non-aqueous zinc-polyaniline secondary battery was fabricated with polyaniline Emeraldine base as cathode and zinc metal as anode in an electrolyte consisting of 0.3 M zinc-bis(trifluoromethyl-sulfonyl)imide Zn(TFSI)2 dissolved in propylene carbonate. We observed that the formation of the battery required a prerequisite condition to stabilize the interfaces in order to maintain a stable capacity. The battery suffered from Zn dissolution which induces a competition between concurrent Zn dissolution and plating when the battery is in charge mode, and thus inefficient cycles are obtained. The capacity and coulombic efficiency of the battery depends on the charge-discharge rates. We propose cycling protocols at different rates to determine the steady-state rates of competing reactions. When the cell is cycled at ≥1 C rate, the coulombic efficiency improves. The maximum capacity and energy densities of the battery are 148 mAhg-1 and 127 mWhg-1, respectively for discharge at C/2. The battery was successively charged/discharged at constant current densities (1C rate), and high cycling stability was obtained for more than 1700 cycles at 99.8% efficiency. Zinc dissolution and self discharge of the battery were investigated after 24 h of standby. The investigation showed that the battery experiences a severe self-discharge of 48% per day.

  3. Highly Quantitative Electrochemical Characterization of Non-Aqueous Electrolytes & Solid Electrolyte Interphases

    Energy Technology Data Exchange (ETDEWEB)

    Sergiy V. Sazhin; Kevin L. Gering; Mason K. Harrup; Harry W. Rollins

    2012-10-01

    The methods to measure solid electrolyte interphase (SEI) electrochemical properties and SEI formation capability of non-aqueous electrolyte solutions are not adequately addressed in the literature. And yet, there is a strong demand in new electrolyte generations that promote stabilized SEIs and have an influence to resolve safety, calendar life and other limitations of Li-ion batteries. To fill this gap, in situ electrochemical approach with new descriptive criteria for highly quantitative characterization of SEI and electrolytes is proposed. These criteria are: SEI formation capacity, SEI corrosion rate, SEI maintenance rate, and SEI kinetic stability. These criteria are associated with battery parameters like irreversible capacity, self-discharge, shelf-life, power, etc. Therefore, they are especially useful for electrolyte development and standard fast screening, allowing a skillful approach to narrow down the search for the best electrolyte. The characterization protocol also allows retrieving information on interfacial resistance for SEI layers and the electrochemical window of electrolytes, the other important metrics of characterization. The method validation was done on electrolyte blends containing phosphazenes, developed at Idaho National Laboratory, as 1.2M LiPF6 [80 % EC-MEC (2:8) (v/v) + 20% Phosphazene variety] (v/v), which were targeted for safer electrolyte variations.

  4. A Long-Wavelength Fluorescent Squarylium Cyanine Dye Possessing Boronic Acid for Sensing Monosaccharides and Glycoproteins with High Enhancement in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Hiroyuki Nakazumi

    2012-04-01

    Full Text Available Fluorescence sensing of saccharides and glycoproteins using a boronic acid functionalized squarylium cyanine dye (“SQ-BA” is characterized in terms of synthetic, fluorometric, thermodynamic and kinetic parameters. In our previous work, this newly synthesized dye was successfully applied to the separation and quantification of Gram-positive bacteria by capillary electrophoresis with laser-induced fluorescence detection (CE-LIF; however, the fundamental properties of the dye and its saccharide complexes still required elucidation, as presented in this paper. The dye itself forms nonemissive, soluble aggregates in aqueous solution. With the addition of a monosaccharide, the dye aggregate dissociates to form an emissive monomer accompanied by the formation of a cyclic cis-diol ester with long-wavelength emission (lex = 630 nm, lem = 660 nm. A very large fluorescence enhancement factor of 18× was observed for the sensing dye as a fructose complex at pH 10, yielding a limit of detection of 10 mM fructose. The relative order of fluorescence enhancement of SQ-BA with other monosaccharides was found to be: fructose > ribose > arabinose ≈ galactose > xylose > mannose > rhamnose > fucose ≈ glucose; and apparent affinity constants of 102.80, 102.08 and 100.86 M−1 were determined for fructose, ribose and glucose, respectively. Formation of the emissive complexes occurred within minutes, proving the kinetics of the sugar-dye interactions to be suitable for on-column labeling methods in CE-LIF. Furthermore, the sensing dye was successfully applied to glycoproteins, mucin type I–S and type III, which were detected with high sensitivity in batch aqueous solution as a result of the sugar-selective boronic acid-diol esterification as well as hydrophobic interactions.

  5. Engineering a high-performance, metagenomic-derived novel xylanase with improved soluble protein yield and thermostability.

    Science.gov (United States)

    Qian, Changli; Liu, Ning; Yan, Xing; Wang, Qian; Zhou, Zhihua; Wang, Qianfu

    2015-03-01

    The novel termite gut metagenomic-derived GH11 xylanase gene xyl7 was expressed in Escherichia coli BL21, and the purified XYL7 enzyme exhibited high specific activity (6340U/mg) and broad pH active range of 5.5-10.0. Directed evolution was employed to enhance the thermostability of XYL7; two mutants (XYL7-TC and XYL7-TS) showed a 250-fold increase in half-life at 55°C, with a 10°C increase in optimal temperature compared to that of wild-type XYL7. A truncated enzyme (XYL7-Tr3) acquired by protein engineering showed similar catalytic properties as the wild-type, with a tenfold increase in soluble protein yield by the mutant. The reducing sugar produced by XYL7-TC was about fourfold greater than that produced by their parents when incubated with xylan at 60°C for 4h. The engineered novel xylanase exhibited superior enzymatic performance and showed promise as an excellent candidate for industrial application due to its high specific activity, stability and soluble protein yield.

  6. Vibrational entropy changes the solid solubility of a random alloy at high temperatures

    Science.gov (United States)

    Shulumba, Nina; Hellman, Olle; Raza, Zamaan; Barrirero, Jenifer; Mücklich, Frank; Abrikosov, Igor A.; Odén, Magnus

    2015-03-01

    We have developed a method to accurately and efficiently determine vibrational entropy as a function of temperature and volume for substitutional alloys from first principles. Using Ti1-xAlxN metal alloy as a model system we calculate the isostructural phase diagram by minimization of the free energy, solving the original Gibbs problem of finding its global minimum corresponding to the true equilibrium state of the system. We demonstrate that the vibrational contribution to the free energy has a decisive impact on the calculated phase diagram of Ti1-xAlxN alloy, lowering the maximum temperature for the miscibility gap from 9000 K to 2400 K. The solubility limit of the predicted phase diagram is experimentally verified by local chemical composition measurements of thermally aged Ti50Al50N alloys. DocMASE, SECO Tools AB, SSF RMA 08-0069 and SRL 10-002, VR 2012-4401 and 637-2013-7296, Vinnova M-ERA.net, MC2, (KAW) (Isotopic Control for Ultimate Material Properties).

  7. Management of high level radioactive aqueous effluents in advanced partitioning processes

    Energy Technology Data Exchange (ETDEWEB)

    Pochon, Patrick; Sans, Daniele; Lartigaud, Cathy; Bisel, Isabelle [Commissariat a l' Energie Atomique, Centre de Marcoule, BP 17171, Bagnols sur Ceze, 30207 (France)

    2009-06-15

    The context of this study is the development of management strategies for the high level radioactive aqueous effluents generated by advanced minor actinides partitioning processes. In the present nuclear reprocessing plants, high level liquid wastes are concentrated via successive evaporations, with or without de-nitration, to reach the inlet specifications of the downstream processing steps. In contrast to the PUREX process, effluents from advanced actinides partitioning processes contain large amounts of organic compounds (complexing agents, buffers or reducing reagents), which could disrupt concentration operations. Thus, in parallel with new partitioning process development, the compatibility of usual concentration operations with the high level liquid waste issued from them are investigated, and, if necessary, additional treatments to eliminate remaining organic compounds are reviewed. The behaviour of each reagent and related identified by-products is studied in laboratory-scale devices representative of industrial operating conditions. Final concentrated solutions (actinide or fission solutions) and the resulting distillates (i.e. decontaminated effluents) are checked in terms of compatibility with the downstream specifications. Process implementation and safety aspects are also evaluated. Kinetic and thermodynamic constants are measured. After the collection of these data, the effectiveness of the overall continuous process of the effluent treatment (combination of elementary operations) is evaluated through semi-empirical models which are also able to optimize the conditions for implementation. First results indicate that nitric acid streams containing complexing agents (oxalic acid, HEDTA, DTPA) will be managed by usual concentration processes, while buffered solutions ( containing glycolic, citric or malonic acid) will require additional treatments to lower organic carbon concentration. Oxidation process by hydrogen peroxide at boiling temperature has

  8. Enthalpy of absorption and limit of solubility of CO{sub 2} in aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol, 2-[2-(dimethyl-amino)ethoxy] ethanol, and 3-dimethyl-amino-1-propanol at T = (313.15 and 353.15) K and pressures up to 2 MPa

    Energy Technology Data Exchange (ETDEWEB)

    Rodier, Laurence; Ballerat-Busserolles, Karine [Clermont Universite, Universite Blaise Pascal, Laboratoire de Thermodynamique et Interactions Moleculaires, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6272, Laboratoire de Thermodynamique et Interactions Moleculaires, F-63173 Aubiere (France); Coxam, Jean-Yves, E-mail: j-yves.coxam@univ-bpclermont.f [Clermont Universite, Universite Blaise Pascal, Laboratoire de Thermodynamique et Interactions Moleculaires, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6272, Laboratoire de Thermodynamique et Interactions Moleculaires, F-63173 Aubiere (France)

    2010-06-15

    In order to study the influence of amine structure on absorption of carbon dioxide, enthalpies of solution of CO{sub 2} in 2.50 mol . L{sup -1} aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (THAM), 2-[2-(dimethyl-amino)ethoxy] ethanol (DMAEOE), and 3-dimethyl-amino-1-propanol (DMAP) were measured. The enthalpies of solution are determined as function of gas loading charge (moles of CO{sub 2}/mole of amine), at temperatures (313.15 and 353.15) K, and pressures range from (0.5 to 2) MPa. Measurements were carried out using a flow calorimetric technique. CO{sub 2} solubilities in the aqueous solutions of amine are derived from calorimetric data. Molar volumes of aqueous amine solutions required to handle calorimetric data were determined at 303.15 K using a vibrating tube densimeter. Experimental enthalpies of solution are discussed on the basis of amines alkalinity.

  9. High energy density capacitor using coal tar pitch derived nanoporous carbon/MnO{sub 2} electrodes in aqueous electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Tomko, Timothy [Energy and Mineral Engineering, University Park, PA 16802 (United States); Rajagopalan, Ramakrishnan; Lanagan, Michael [Materials Research Institute, University Park, PA 16802 (United States); Foley, Henry C. [Department of Chemical Engineering, University Park, PA 16802 (United States)

    2011-02-15

    Asymmetric aqueous electrochemical capacitors with energy densities as high as 22 Wh kg{sup -1}, power densities of 11 kW kg{sup -1} and a cell voltage of 2 V were fabricated using cost effective, high surface carbon derived from coal tar pitch and manganese dioxide. The narrow pore size distribution of the activated carbon (mean pore size {proportional_to}0.8 nm) resulted in strong electroadsorption of protons making them suitable for use as negative electrodes. Amorphous manganese dioxide anodes were synthesized by chemical precipitation method with high specific capacitance (300 F g{sup -1}) in aqueous electrolytes containing bivalent cations. The fabricated capacitors demonstrated excellent cyclability with no signs of capacitance fading even after 1000 cycles. (author)

  10. Use of adenylate kinase as a solubility tag for high level expression of T4 DNA ligase in Escherichia coli.

    Science.gov (United States)

    Liu, Xinxin; Huang, Anliang; Luo, Dan; Liu, Haipeng; Han, Huzi; Xu, Yang; Liang, Peng

    2015-05-01

    The discovery of T4 DNA ligase in 1960s was pivotal in the spread of molecular biotechnology. The enzyme has become ubiquitous for recombinant DNA routinely practiced in biomedical research around the globe. Great efforts have been made to express and purify T4 DNA ligase to meet the world demand, yet over-expression of soluble T4 DNA ligase in E. coli has been difficult. Here we explore the use of adenylate kinase to enhance T4 DNA ligase expression and its downstream purification. E.coli adenylate kinase, which can be expressed in active form at high level, was fused to the N-terminus of T4 DNA ligase. The resulting His-tagged AK-T4 DNA ligase fusion protein was greatly over-expressed in E. coli, and readily purified to near homogeneity via two purification steps consisting of Blue Sepharose and Ni-NTA chromatography. The purified AK-T4 DNA ligase not only is fully active for DNA ligation, but also can use ADP in addition to ATP as energy source since adenylate kinase converts ADP to ATP and AMP. Thus adenylate kinase may be used as a solubility tag to facilitate recombinant protein expression as well as their downstream purification.

  11. High-level expression and purification of recombinant human growth hormone produced in soluble form in Escherichia coli.

    Science.gov (United States)

    Levarski, Zdenko; Šoltýsová, Andrea; Krahulec, Ján; Stuchlík, Stanislav; Turňa, Ján

    2014-08-01

    Human growth hormone (hGH) was one of the first recombinant proteins approved for the treatment of human growth disorders. Its small size (191 amino acids), possession of only 2 disulphide bonds and absence of posttranslational modifications make Escherichia coli the host of choice for its production on any scale. In this work, we have utilized an efficient T7 based expression system to produce high levels of soluble thioredoxin-hGH (Trx-hGH) fusion protein. We outline a relatively simple three step purification process employing two immobilized metal-affinity chromatography and one anion-exchange steps and removal of fusion partner by enterokinase cleavage yielding native hGH. The ability of cell populations to produce quantities of up to 1 g/L of the soluble Trx-hGH fusion protein has been tested in flask cultivations as well as in batch and fed-batch bioreactor runs. The sequence and structure of derived hGH were confirmed by mass spectrometry and circular dichroism and its native function, to induce cell proliferation, was confirmed by employing a Nb2 cell line proliferation assay.

  12. Highly luminescent water-soluble quaternary Zn-Ag-In-S quantum dots for tumor cell-targeted imaging.

    Science.gov (United States)

    Deng, Dawei; Cao, Jie; Qu, Lingzhi; Achilefu, Samuel; Gu, Yueqing

    2013-04-14

    Exploring the synthesis and biomedical applications of biocompatible quantum dots (QDs) is currently one of the fastest growing fields of nanotechnology. Hence, in this work, we present a facile approach to produce water-soluble (cadmium-free) quaternary Zn-Ag-In-S (ZAIS) QDs. Their efficient photoluminescence (PL) emissions can be tuned widely in the range of 525-625 nm by controlling the size and composition of the QDs with the PL quantum yields (QYs) of 15-30%. These highly luminescent ZAIS QDs are less toxic due to the absence of highly toxic cadmium, and can be versatilely modified by a DHLA-PEG-based ligand. Importantly, after being modified by tumor cell-specific targeting ligands (e.g., folate and RGD peptide), the PEGylated quaternary QDs show potential applications in tumor cell imaging as a promising alternative for Cd-based QDs.

  13. Soluble Fermentable Dietary Fibre (Pectin Decreases Caloric Intake, Adiposity and Lipidaemia in High-Fat Diet-Induced Obese Rats.

    Directory of Open Access Journals (Sweden)

    Clare L Adam

    Full Text Available Consumption of a high fat diet promotes obesity and poor metabolic health, both of which may be improved by decreasing caloric intake. Satiety-inducing ingredients such as dietary fibre may be beneficial and this study investigates in diet-induced obese (DIO rats the effects of high or low fat diet with or without soluble fermentable fibre (pectin. In two independently replicated experiments, young adult male DIO rats that had been reared on high fat diet (HF; 45% energy from fat were given HF, low fat diet (LF; 10% energy from fat, HF with 10% w/w pectin (HF+P, or LF with 10% w/w pectin (LF+P ad libitum for 4 weeks (n = 8/group/experiment. Food intake, body weight, body composition (by magnetic resonance imaging, plasma hormones, and plasma and liver lipid concentrations were measured. Caloric intake and body weight gain were greatest in HF, lower in LF and HF+P, and lowest in the LF+P group. Body fat mass increased in HF, was maintained in LF, but decreased significantly in LF+P and HF+P groups. Final plasma leptin, insulin, total cholesterol and triglycerides were lower, and plasma satiety hormone PYY concentrations were higher, in LF+P and HF+P than in LF and HF groups, respectively. Total fat and triglyceride concentrations in liver were greatest in HF, lower in LF and HF+P, and lowest in the LF+P group. Therefore, the inclusion of soluble fibre in a high fat (or low fat diet promoted increased satiety and decreased caloric intake, weight gain, adiposity, lipidaemia, leptinaemia and insulinaemia. These data support the potential of fermentable dietary fibre for weight loss and improving metabolic health in obesity.

  14. Soluble Fermentable Dietary Fibre (Pectin) Decreases Caloric Intake, Adiposity and Lipidaemia in High-Fat Diet-Induced Obese Rats

    Science.gov (United States)

    Adam, Clare L.; Thomson, Lynn M.; Williams, Patricia A.; Ross, Alexander W.

    2015-01-01

    Consumption of a high fat diet promotes obesity and poor metabolic health, both of which may be improved by decreasing caloric intake. Satiety-inducing ingredients such as dietary fibre may be beneficial and this study investigates in diet-induced obese (DIO) rats the effects of high or low fat diet with or without soluble fermentable fibre (pectin). In two independently replicated experiments, young adult male DIO rats that had been reared on high fat diet (HF; 45% energy from fat) were given HF, low fat diet (LF; 10% energy from fat), HF with 10% w/w pectin (HF+P), or LF with 10% w/w pectin (LF+P) ad libitum for 4 weeks (n = 8/group/experiment). Food intake, body weight, body composition (by magnetic resonance imaging), plasma hormones, and plasma and liver lipid concentrations were measured. Caloric intake and body weight gain were greatest in HF, lower in LF and HF+P, and lowest in the LF+P group. Body fat mass increased in HF, was maintained in LF, but decreased significantly in LF+P and HF+P groups. Final plasma leptin, insulin, total cholesterol and triglycerides were lower, and plasma satiety hormone PYY concentrations were higher, in LF+P and HF+P than in LF and HF groups, respectively. Total fat and triglyceride concentrations in liver were greatest in HF, lower in LF and HF+P, and lowest in the LF+P group. Therefore, the inclusion of soluble fibre in a high fat (or low fat) diet promoted increased satiety and decreased caloric intake, weight gain, adiposity, lipidaemia, leptinaemia and insulinaemia. These data support the potential of fermentable dietary fibre for weight loss and improving metabolic health in obesity. PMID:26447990

  15. Soluble Fermentable Dietary Fibre (Pectin) Decreases Caloric Intake, Adiposity and Lipidaemia in High-Fat Diet-Induced Obese Rats.

    Science.gov (United States)

    Adam, Clare L; Thomson, Lynn M; Williams, Patricia A; Ross, Alexander W

    2015-01-01

    Consumption of a high fat diet promotes obesity and poor metabolic health, both of which may be improved by decreasing caloric intake. Satiety-inducing ingredients such as dietary fibre may be beneficial and this study investigates in diet-induced obese (DIO) rats the effects of high or low fat diet with or without soluble fermentable fibre (pectin). In two independently replicated experiments, young adult male DIO rats that had been reared on high fat diet (HF; 45% energy from fat) were given HF, low fat diet (LF; 10% energy from fat), HF with 10% w/w pectin (HF+P), or LF with 10% w/w pectin (LF+P) ad libitum for 4 weeks (n = 8/group/experiment). Food intake, body weight, body composition (by magnetic resonance imaging), plasma hormones, and plasma and liver lipid concentrations were measured. Caloric intake and body weight gain were greatest in HF, lower in LF and HF+P, and lowest in the LF+P group. Body fat mass increased in HF, was maintained in LF, but decreased significantly in LF+P and HF+P groups. Final plasma leptin, insulin, total cholesterol and triglycerides were lower, and plasma satiety hormone PYY concentrations were higher, in LF+P and HF+P than in LF and HF groups, respectively. Total fat and triglyceride concentrations in liver were greatest in HF, lower in LF and HF+P, and lowest in the LF+P group. Therefore, the inclusion of soluble fibre in a high fat (or low fat) diet promoted increased satiety and decreased caloric intake, weight gain, adiposity, lipidaemia, leptinaemia and insulinaemia. These data support the potential of fermentable dietary fibre for weight loss and improving metabolic health in obesity.

  16. High-level expression and purification of soluble recombinant FGF21 protein by SUMO fusion in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Huang Yadong

    2010-02-01

    Full Text Available Abstract Background Fibroblast growth factor 21 (FGF21 is a promising drug candidate to combat metabolic diseases. However, high-level expression and purification of recombinant FGF21 (rFGF21 in Escherichia coli (E. coli is difficult because rFGF21 forms inclusion bodies in the bacteria making it difficult to purify and obtain high concentrations of bioactive rFGF21. To overcome this problem, we fused the FGF21 with SUMO (Small ubiquitin-related modifier by polymerase chain reaction (PCR, and expressed the fused gene in E. coli BL21(DE3. Results By inducing with IPTG, SUMO-FGF21 was expressed at a high level. Its concentration reached 30% of total protein, and exceeded 95% of all soluble proteins. The fused protein was purified by DEAE sepharose FF and Ni-NTA affinity chromatography. Once cleaved by the SUMO protease, the purity of rFGF21 by high performance liquid chromatography (HPLC was shown to be higher than 96% with low endotoxin level (in vivo animal experiments showed that rFGF21 produced by using this method, could decrease the concentration of plasma glucose in diabetic rats by streptozotocin (STZ injection. Conclusions This study demonstrated that SUMO, when fused with FGF21, was able to promote its soluble expression of the latter in E. coli, making it more convenient to purify rFGF21 than previously. This may be a better method to produce rFGF21 for pharmaceutical research and development.

  17. Aqueous processing of U-10Mo scrap for high performance research reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Youker, Amanda J., E-mail: youker@anl.gov [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Stepinski, Dominique C.; Maggos, Laura E.; Bakel, Allen J.; Vandegrift, George F. [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer GTRI program supports conversion from HEU to LEU. Black-Right-Pointing-Pointer High performance research reactors require a dense LEU fuel such as U-10Mo foils. Black-Right-Pointing-Pointer Dissolution conditions for U-10Mo foils in acidic media have been optimized. Black-Right-Pointing-Pointer Solvent-extraction processing can be used to recover U lost in fuel fabrication. Black-Right-Pointing-Pointer Flowsheets were developed using Argonne-design contactors but other contactors can be used as well. - Abstract: The Global Threat Reduction Initiative (GTRI) Conversion program, which is part of the US government's National Nuclear Security Administration (NNSA), supports the conversion of civilian use of highly enriched uranium (HEU) to low enriched uranium (LEU) for reactor fuel and targets. The reason for conversion is to eliminate the use of any material that may pose a threat to the United States or other foreign countries. High performance research reactors (HPRRs) cannot make the conversion to a standard LEU fuel because they require a more dense fuel to meet their performance requirements. As a result, a more dense fuel consisting of a monolithic uranium-molybdenum alloy containing 10% (w/w) Mo with Al cladding and a Zr bonding-layer is being considered. Significant losses are expected in the fabrication of this fuel, so a means to recycle the scrap pieces is needed. Argonne National Laboratory has developed an aqueous-processing flowsheet for scrap recovery in the fuel fabrication process for high-density LEU-monolithic fuel based on data found in the literature. Experiments have been performed to investigate dissolution conditions for solutions containing approximately 20 g-U/L and 50 g-U/L with and without Fe(NO{sub 3}){sub 3}. HNO{sub 3} and HF concentrations have been optimized for timely dissolution of the fuel scrap and prevention of the formation of the U-Zr{sub 2} intermetallic, explosive complex, while

  18. Low-Temperature Preparation and Properties of High Activity Anatase TiO2 Aqueous Sols

    Science.gov (United States)

    Liu, Qingju; Na, Wei; Zhu, Zhongqi; Zhang, Jin

    2011-06-01

    Anatase TiO2 aqueous sols were prepared below 70 °C by sol method. The influences of preparing conditions on the crystal structures and stability of the sols were investigated with X-ray diffraction (XRD) and Zeta potential. The photocatalytic activities of the anatase TiO2 aqueous sols were characterized by degradation of methyl orange and methylene blue under ultraviolet light, fluorescent light and sunlight. The sols demonstrate higher photocatalytic activity than that of Degussa P25-TiO2.

  19. A three-layer guar gum matrix tablet for oral controlled delivery of highly soluble metoprolol tartrate.

    Science.gov (United States)

    Krishnaiah, Y S R; Karthikeyan, R S; Satyanarayana, V

    2002-07-25

    The objective of the study is to design oral controlled drug delivery systems for highly water-soluble drugs using guar gum as a carrier in the form of a three-layer matrix tablet. Metoprolol tartrate was chosen as a model drug because of its high water solubility. Matrix tablets containing either 30 (M1), 40 (M2) or 50% (M3) of guar gum were prepared by wet granulation technique using starch paste as a binder. Three-layer matrix tablets of metoprolol tartrate were prepared by compressing on both sides of guar gum matrix tablet granules of metoprolol tartrate M1, M2 or M3 with either 50 (TL1M1, TL1M2 or TL1M3) or 75 mg (TL2M1, TL2M2 or TL2M3) of guar gum granules as release retardant layers. Both the matrix and three-layer matrix tablets were evaluated for hardness, thickness, drug content uniformity, and subjected to in vitro drug release studies. The amount of metoprolol tartrate released from the matrix and three-layer matrix tablets at different time intervals was estimated by using a HPLC method. Matrix tablets of metoprolol tartrate were unable to provide the required drug release rate. However, the three-layer guar gum matrix tablets (TL2M3) provided the required release rate on par with the theoretical release rate for metoprolol tartrate formulations meant for twice daily administration. The three-layer guar gum matrix tablet (TL2M3) showed no change either in physical appearance, drug content or in dissolution pattern after storage at 40 degrees C/75% RH for 6 months. The FT-IR study did not show any possibility of metoprolol tartrate/guar gum interaction with the formulation excipients used in the study. The results indicated that guar gum, in the form of three-layer matrix tablets, is a potential carrier in the design of oral controlled drug delivery systems for highly water-soluble drugs such as metoprolol tartrate.

  20. A novel electrospinning approach to fabricate high strength aqueous silk fibroin nanofibers.

    Science.gov (United States)

    Singh, B N; Panda, N N; Pramanik, K

    2016-06-01

    The present paper describes a rapid method of producing concentrated aqueous regenerated Bombyx mori silk fibroin (RSF) solution by applying mild shearing under forced dehumidified air and generation of electrospun SF nanofibers from concentrated solution with high mechanical strength using free liquid surface electrospinning machine. The shear induced concentrating mechanism favoured the electrospinning process by enhancing the viscosity (>2.43Pas as onset for electrospinning) and decreasing the surface tension of the solution (40.1-37.7mN/m). Shearing reduced the β-turns and random coil molecular conformation and thereby, intensified the β-sheet content from 16.9% to 34% which is the minimum content needed to commence RSF nanofibers formation. Subsequently, electrospun nanofibrous mats were produced from different batches of concentrated SF solutions (15-21wt%). Among the concentrated RSF, 17wt% RSF solution was the most favourable concentration producing electrospun nanofibrous mat having lowest average fiber diameters of 183±55nm and good tensile strength. The mechanical strength of the nanofibrous sheet was further improved by cross-linking with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide (EDC+NHS) which might be due to enhancement of β-sheet content. These nanofibers exhibited 17.57±1.13MPa ultimate tensile strength, 12.48±1.46% tensile strain at break and 37.7% increase in root mean square surface roughness which is favourable feature for cell adhesion and neo-tissue formation.

  1. SANS from Salt-Free Aqueous Solutions of Hydrophilic and Highly Charged Star-Branched Polyelectrolytes

    Directory of Open Access Journals (Sweden)

    François Boué

    2016-06-01

    Full Text Available Scattering functions of sodium sulfonated polystyrene (NaPSS star-branched polyelectrolytes with high sulfonation degrees were measured from their salt-free aqueous solutions, using the Small Angle Neutron Scattering (SANS technique. Whatever the concentration c, they display two maxima. The first, of abscissa q1*, is related to a position order between star cores and scales as q1* ∝ c1/3. The second, of abscissa q2*, is also observed in the scattering function of a semi-dilute solution of NaPSS linear polyelectrolytes. In the dilute regime (c < c*, non-overlapping stars, peak abscissa does not depend on concentration c and is just an intramolecular characteristic associated with the electrostatic repulsion between arms of the same star. In the semi-dilute regime, due to the star interpenetration, the scattering function – through the peak position, reflects repulsion between arms of the same star or of different stars. The c threshold between these distinct c-dependencies of q2* in the dilute and semi-dilute regimes is estimated as c*. Just as simple is the measurement of the geometrical radius R of the star obtained from the q1* value at c* through the relation 2R = 2π/q1*. By considering NaPSS stars of the same functionality with different degrees of polymerization per arm Na, we find R scaling linearly with Na, suggesting an elongated average conformation of the arms. This is in agreement with theoretical predictions and simulations. Meanwhile the value of q2* measured in the dilute regime does not allow any inhomogeneous counterion distribution inside the stars to be revealed.

  2. Antiobesity and Hypoglycaemic Effects of Aqueous Extract of Ibervillea sonorae in Mice Fed a High-Fat Diet with Fructose

    Directory of Open Access Journals (Sweden)

    Fabiola Rivera-Ramírez

    2011-01-01

    Full Text Available Obesity, type II diabetes, and hyperlipidaemia, which frequently coexist and are strongly associated with oxidative stress, increase the risk of cardiovascular disease. An increase in carbohydrate intake, especially of fructose, and a high-fat diet are both factors that contribute to the development of these metabolic disorders. In recent studies carried out in diabetic rats, authors reported that Ibervillea sonorae had hypoglycaemic activity; saponins and monoglycerides present in the plant could be responsible for the effects observed. In the present study, we determined the effects of an aqueous I. sonorae extract on a murine model of obesity and hyperglycaemia, induced by a high-calorie diet, and the relationship of these effects with hepatic oxidation. A high-fat diet over a period of 8 weeks induced weight gain in the mice and increased triglycerides and blood glucose levels. Simultaneous treatment with I. sonorae aqueous extracts, at doses of 100, 200, and 400 mg/kg, decreased triglycerides and glycaemia levels, prevented an increase in body weight in a dose-dependent manner, and decreased hepatic lipid oxidation at a dose of 200 mg/kg. These data suggest that the aqueous extract from I. sonorae root prevents obesity, dyslipidaemia, and hyperglycaemia induced by a hypercaloric diet; however, high doses may induce toxicity.

  3. Antiobesity and Hypoglycaemic Effects of Aqueous Extract of Ibervillea sonorae in Mice Fed a High-Fat Diet with Fructose

    Science.gov (United States)

    Rivera-Ramírez, Fabiola; Escalona-Cardoso, Gerardo N.; Garduño-Siciliano, Leticia; Galaviz-Hernández, Carlos; Paniagua-Castro, Norma

    2011-01-01

    Obesity, type II diabetes, and hyperlipidaemia, which frequently coexist and are strongly associated with oxidative stress, increase the risk of cardiovascular disease. An increase in carbohydrate intake, especially of fructose, and a high-fat diet are both factors that contribute to the development of these metabolic disorders. In recent studies carried out in diabetic rats, authors reported that Ibervillea sonorae had hypoglycaemic activity; saponins and monoglycerides present in the plant could be responsible for the effects observed. In the present study, we determined the effects of an aqueous I. sonorae extract on a murine model of obesity and hyperglycaemia, induced by a high-calorie diet, and the relationship of these effects with hepatic oxidation. A high-fat diet over a period of 8 weeks induced weight gain in the mice and increased triglycerides and blood glucose levels. Simultaneous treatment with I. sonorae aqueous extracts, at doses of 100, 200, and 400 mg/kg, decreased triglycerides and glycaemia levels, prevented an increase in body weight in a dose-dependent manner, and decreased hepatic lipid oxidation at a dose of 200 mg/kg. These data suggest that the aqueous extract from I. sonorae root prevents obesity, dyslipidaemia, and hyperglycaemia induced by a hypercaloric diet; however, high doses may induce toxicity. PMID:22174560

  4. Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage

    OpenAIRE

    Shan, Xiaoqiang; Charles, Daniel S.; Lei, Yinkai; Qiao, Ruimin; Wang, Guofeng; Yang, Wanli; Feygenson, Mikhail; Su, Dong; Teng, Xiaowei

    2016-01-01

    Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost and environmental friendliness. However, their applications have been limited by a narrow potential window (∼1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here we report the formation of layered Mn5O8 pseudocapacitor electrode material with a well-ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable po...

  5. Preparation of pellets containing highly soluble drug by extrusion/spheronisation and coating with Kollicoat® SR 30D

    Directory of Open Access Journals (Sweden)

    Itamar Francisco Andreazza

    2011-04-01

    Full Text Available The aim of this study was to prepare and evaluate the pellets, containing a highly soluble drug (ascorbic acid, by the extrusion-spheronization process and coated with a release controlling polymer. The coating (undertaken in a fluid bed was applied to three batches of the pellets with a dispersion of Kollicoat® SR 30 D, with each batch of pellets receiving a different level of polymer (5.07; 8.26 and 10.35%. The coated pellets were evaluated for sphericity by imaging analysis and comparative dissolution profile with a product commercially available in Brazil. All of the evaluated samples presented adequate physical properties and the dissolution profile of those coated with 5.07% of polymer proved to be similar to that of the commercially available brand name.

  6. Simultaneous production of high-quality water and electrical power from aqueous feedstock’s and waste heat by high-pressure membrane distillation

    NARCIS (Netherlands)

    Kuipers, N.J.M.; Hanemaaijer, J.H.; Brouwer, H.; Medevoort, J. van; Jansen, A.; Altena, F.; Vleuten, P. van der; Bak, H.

    2015-01-01

    A new membrane distillation (MD) concept (MemPower) has been developed for the simultaneous production of high-quality water from various aqueous feedstocks with cogeneration of mechanical power (electricity). Driven by low-grade heat (waste, solar, geothermal, etc.) a pressurized distillate can be

  7. Preparation of water-soluble multi-walled carbon nanotubes by Ce(Ⅳ)-induced redox radical polymerization

    Institute of Scientific and Technical Information of China (English)

    Dong Yang; Xiaohong Zhang; Changchun Wang; Yuechao Tang; Junjun Li; Jianhua Hu

    2009-01-01

    Poly(acrylic acid), poly(N-isopropylacrylamide) and polyacrylamide functionalized MWNTs were prepared by Ce(IV)-induced redox radical polymerization. The reaction can be conducted in aqueous media at room temperature, and the polymer graft ratio increased with the increase of monomer feed ratio. MWNTs anchored with PAA on the surface are pH sensitive and exhibit a reversible assembly-deas-sembly response in aqueous solution, whereas those coated with PNIPAM are thermally sensitive. All the polymer-functionalized MWNTs are highly soluble in water to give robust stable black solutions. Such water-soluble MWNTs are promising for biological and biomedical applications.

  8. Development of a salt drug with improved solubility: Ethionamide nitrate

    Science.gov (United States)

    Diniz, Luan F.; Carvalho, Paulo S.; de Melo, Cristiane C.; Ellena, Javier

    2017-06-01

    To avoid drug resistance, an adequate tuberculosis treatment should include not only a first-line drug but also at least one second-line drug such as, for example, Ethionamide (ETH). However, the dissolution rate and oral absorption of ETH is highly limited by its low aqueous solubility. Considering that a salt is in general more soluble than its parent compound, herein we depicted a new supramolecular modification of ETH, an Ethionamide nitrate salt (ETHNO3). This salt is the first ETH structure that has been crystallized with four independent ionic pairs (ETH+NO3-) in the asymmetric unit. In addition to the structural study, the salt formation was also identified on the FT-IR and FT-Raman spectra. The thermal behavior of ETHNO3 was also investigated here together with its solubility profile in three dissolution media (purified water, pH 4.0 and 7.0).

  9. Phytotoxicity of soluble graphitic nanofibers to model plant species.

    Science.gov (United States)

    Gorka, Danielle E; Jeger, Jonathan Litvak; Zhang, Hongbo; Ma, Yanwen; Colman, Benjamin P; Bernhardt, Emily S; Liu, Jie

    2016-12-01

    Carbon nanomaterials are considered promising for applications in energy storage, catalysis, and electronics. This has motivated study of their potential environmental toxicity. Recently, a novel nanomaterial consisting of graphene oxide wrapped around a carbon nanotube (CNT) core was synthesized. The resulting soluble graphitic nanofibers were found to have superior catalytic properties, which could result in their use in fuel cells. Before this material undergoes widespread use, its environmental toxicity must be determined because of its aqueous solubility. The authors used the plant species Lolium multiflorum, Solanum lycopersicum, and Lactuca sativa to study the toxicity of the soluble graphitic nanofibers, as well as multiwalled carbon nanotubes (MWCNTs) and graphene oxide, all synthesized in-house. Soluble graphitic nanofiber-exposed plant roots and shoots showed decreased growth, with roots showing more toxicity than shoots. Decreased pH of nanomaterial solutions corresponded to insignificantly decreased root growth, suggesting that another mechanism of toxicity must exist. Agglomeration and adsorption of soluble graphitic nanofibers onto the roots likely caused the remaining toxicity because a gray layer could be seen around the surface of the root. Multiwalled carbon nanotubes showed little toxicity over the concentration range tested, whereas graphene oxide showed a unique pattern of high toxicity at both the lowest and highest concentrations tested. Overall, soluble graphitic nanofibers showed moderate toxicity between that of the more toxic graphene oxide and the relatively nontoxic MWCNTs. Environ Toxicol Chem 2016;35:2941-2947. © 2016 SETAC.

  10. Polymer-free nanofibers from vanillin/cyclodextrin inclusion complexes: high thermal stability, enhanced solubility and antioxidant property.

    Science.gov (United States)

    Celebioglu, Asli; Kayaci-Senirmak, Fatma; İpek, Semran; Durgun, Engin; Uyar, Tamer

    2016-07-13

    Vanillin/cyclodextrin inclusion complex nanofibers (vanillin/CD-IC NFs) were successfully obtained from three modified CD types (HPβCD, HPγCD and MβCD) in three different solvent systems (water, DMF and DMAc) via an electrospinning technique without using a carrier polymeric matrix. Vanillin/CD-IC NFs with uniform and bead-free fiber morphology were successfully produced and their free-standing nanofibrous webs were obtained. The polymer-free CD/vanillin-IC-NFs allow us to accomplish a much higher vanillin loading (∼12%, w/w) when compared to electrospun polymeric nanofibers containing CD/vanillin-IC (∼5%, w/w). Vanillin has a volatile nature yet, after electrospinning, a significant amount of vanillin was preserved due to complex formation depending on the CD types. Maximum preservation of vanillin was observed for vanillin/MβCD-IC NFs which is up to ∼85% w/w, besides, a considerable amount of vanillin (∼75% w/w) was also preserved for vanillin/HPβCD-IC NFs and vanillin/HPγCD-IC NFs. Phase solubility studies suggested a 1 : 1 molar complexation tendency between guest vanillin and host CD molecules. Molecular modelling studies and experimental findings revealed that vanillin : CD complexation was strongest for MβCD when compared to HPβCD and HPγCD in vanillin/CD-IC NFs. For vanillin/CD-IC NFs, water solubility and the antioxidant property of vanillin was improved significantly owing to inclusion complexation. In brief, polymer-free vanillin/CD-IC NFs are capable of incorporating a much higher loading of vanillin and effectively preserve volatile vanillin. Hence, encapsulation of volatile active agents such as flavor, fragrance and essential oils in electrospun polymer-free CD-IC NFs may have potential for food related applications by integrating the particularly large surface area of NFs with the non-toxic nature of CD and inclusion complexation benefits, such as high temperature stability, improved water solubility and an enhanced

  11. Directs measurement of high temperature/high pressure solubility of methane and carbon dioxide in polyamide (PA-11) using a high-pressure microbalance

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Rubin, A; Andersen, Simon Ivar

    2005-01-01

    Experiments to determine the Solubility of methane and carbon dioxide in PA-11 have been performed in the temperature range 50-90&DEG; C and the pressure ranges 50-150 bar for methane and 20-40 bar for carbon dioxide. In general, the results agree fairly well with previous experiments for similar...... to more uncertainty than the solubility measurements, the expected (Arrhenius) trends are observed. Agreement with other experimental data using different methods is also good....

  12. A highly selective copper-indium bimetallic electrocatalyst for the electrochemical reduction of aqueous CO2to CO

    KAUST Repository

    Rasul, Shahid

    2014-12-23

    The challenge in the electrochemical reduction of aqueous carbon dioxide is in designing a highly selective, energy-efficient, and non-precious-metal electrocatalyst that minimizes the competitive reduction of proton to form hydrogen during aqueous CO2 conversion. A non-noble metal electrocatalyst based on a copper-indium (Cu-In) alloy that selectively converts CO2 to CO with a low overpotential is reported. The electrochemical deposition of In on rough Cu surfaces led to Cu-In alloy surfaces. DFT calculations showed that the In preferentially located on the edge sites rather than on the corner or flat sites and that the d-electron nature of Cu remained almost intact, but adsorption properties of neighboring Cu was perturbed by the presence of In. This preparation of non-noble metal alloy electrodes for the reduction of CO2 provides guidelines for further improving electrocatalysis.

  13. Spray pattern and droplet size analyses for high-shear viscosity determination of aqueous suspension corticosteroid nasal sprays.

    Science.gov (United States)

    Pennington, Justin; Pandey, Preetanshu; Tat, Henry; Willson, Jennifer; Donovan, Brent

    2008-09-01

    Aqueous suspension corticosteroid nasal sprays exhibit the rheological property of shear thinning, meaning they exhibit a decrease in viscosity upon application of shear. Most rheological methods are limited in the amount of shear that can be applied to samples (approximately 1,000 s(-1)) and thus can only approximate the viscosities at the high-shear conditions of nasal spray devices (approximately 10(5)-10(6) s(-1)). In the current work, spray area and droplet size were shown to demonstrate viscosity dependence. Three Newtonian fluids were used to determine equations to approximate viscosity at the spray nozzle from correlations to spray area and droplet size using a standard 100 microL Pfeiffer nasal spray pump. Several shear-thinning solutions, including four commercial aqueous suspension corticosteroid nasal sprays and three aqueous Avicel (1, 2, and 3%, wt/wt) samples, were analyzed to demonstrate the ability of spray area and droplet size analysis to estimate high-shear viscosities. The calculated viscosity values trend in accordance with the rheometer data along with the ability to distinguish differences between all samples analyzed.

  14. The oxidation and hydriding of zircaloy fuel cladding in high temperature aqueous solutions

    Science.gov (United States)

    Chen, Yingzi

    at the metal/film interface control the rate of film growth when the potential is displaced in the positive direction, whereas the kinetics of dissolution of the barrier layer at the barrier layer/solution interface control the rate of passive film thinning when the potential is stepped in the negative direction. Both the growth rate and dissolution rate of the passive films formed in the hydrogenated solution are lower than that formed in the dehydrogenated solution. In addition, the effects of second phase particles (SPPs) on the electrochemistry of passive zirconium in the hydrogenated, high temperature aqueous solutions are examined by using different heat-treated Zircaloy-4 samples; i.e., as-received, beta-quenched, and alpha-annealed. Optical microscopy with polarized light and scanning electron microscopy (SEM) were used to characterize the microstructure and determine the size and density of the SPPs. The average size of the second phase particles in the Zircaloy-4 samples was in the sequence of beta-quenched electrical path across the passive film, which would explain the effect of the size and the density of the SPPs, and hence heat treatment, on the corrosion properties of passive Zircaloy-4.

  15. Photophysics of silicon phthalocyanines in aqueous media.

    Science.gov (United States)

    Doane, Tennyson L; Chuang, Chi-Hung; Chomas, Andrew; Burda, Clemens

    2013-02-04

    Phthalocyanines have been used as photodynamic therapy (PDT) agents because of their uniquely favorable optical properties and high photostability. They have been shown to be highly successful for the treatment of cancer through efficient singlet-oxygen ((1)O(2)) production. However, due to their hydrophobic properties, the considerations of solubility and cellular location have made understanding their photophysics in vitro and in vivo difficult. Indeed, many quantitative assessments of PDT reagents are undertaken in purely organic solvents, presenting challenges for interpreting observations during practical application in vivo. With steady-state and time-resolved laser spectroscopy, we show that for axial ligated silicon phthalocyanines in aqueous media, both the water:lipophile ratio and the pH have drastic effects on their photophysics, and ultimately dictate their functionality as PDT drugs. We suggest that considering the presented photophysics for PDT drugs in aqueous solutions leads to guidelines for a next generation of even more potent PDT agents.

  16. Maximal release of highly bifidogenic soluble dietary fibers from industrial potato pulp by minimal enzymatic treatment

    DEFF Research Database (Denmark)

    Thomassen, Lise Vestergaard; Vigsnæs, Louise Kristine; Licht, Tine Rask

    2011-01-01

    Potato pulp is a poorly utilized, high-volume co-processing product resulting from industrial potato starch manufacturing. Potato pulp mainly consists of the tuber plant cell wall material and is particularly rich in pectin, notably galactan branched rhamnogalacturonan I type pectin which has...

  17. Highly conjugated water soluble CdSe quantum dots to multiwalled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Gui Zheng Zou

    2009-01-01

    Highly conjugated multiwalled carbon nanotube-quantum dot heterojunctions were synthesized by ethylene carbodiimide coupling procedure. The functional multiwalled carbon nanotube with carboxylic groups on sidewall could react with the amino group of L-cysteine capped CdSe quantum dots and then resulted in nanotube-quantum dot heterojunctions. Scanning electron microscopy was used to characterize the heterojunctions.

  18. High levels of soluble serum hemojuvelin in patients with congenital dyserythropoietic anemia type I

    NARCIS (Netherlands)

    Shalev, H.; Perez-Avraham, G.; Kapelushnik, J.; Levi, I.; Rabinovich, A.; Swinkels, D.W.; Brasse-Lagnel, C.; Tamary, H.

    2013-01-01

    OBJECTIVE: Congenital dyserythropoietic anemia (CDA) is a rare group of red blood cell disorders with ineffective erythropoiesis and secondary hemochromatosis. Inappropriate suppression of hepcidin and high levels of growth differentiation factor 15 (GDF15) have been described in CDA I and II patien

  19. High levels of soluble serum hemojuvelin in patients with congenital dyserythropoietic anemia type I

    NARCIS (Netherlands)

    Shalev, H.; Perez-Avraham, G.; Kapelushnik, J.; Levi, I.; Rabinovich, A.; Swinkels, D.W.; Brasse-Lagnel, C.; Tamary, H.

    2013-01-01

    OBJECTIVE: Congenital dyserythropoietic anemia (CDA) is a rare group of red blood cell disorders with ineffective erythropoiesis and secondary hemochromatosis. Inappropriate suppression of hepcidin and high levels of growth differentiation factor 15 (GDF15) have been described in CDA I and II patien

  20. Utilization of paramagnetic relaxation enhancements for high-resolution NMR structure determination of a soluble loop-rich protein with sparse NOE distance restraints

    Energy Technology Data Exchange (ETDEWEB)

    Furuita, Kyoko; Kataoka, Saori; Sugiki, Toshihiko; Hattori, Yoshikazu; Kobayashi, Naohiro; Ikegami, Takahisa [Osaka University, Institute for Protein Research (Japan); Shiozaki, Kazuhiro [Nara Institute of Science and Technology, Graduate School of Biological Sciences (Japan); Fujiwara, Toshimichi; Kojima, Chojiro, E-mail: kojima@protein.osaka-u.ac.jp [Osaka University, Institute for Protein Research (Japan)

    2015-01-15

    NMR structure determination of soluble proteins depends in large part on distance restraints derived from NOE. In this study, we examined the impact of paramagnetic relaxation enhancement (PRE)-derived distance restraints on protein structure determination. A high-resolution structure of the loop-rich soluble protein Sin1 could not be determined by conventional NOE-based procedures due to an insufficient number of NOE restraints. By using the 867 PRE-derived distance restraints obtained from the NOE-based structure determination procedure, a high-resolution structure of Sin1 could be successfully determined. The convergence and accuracy of the determined structure were improved by increasing the number of PRE-derived distance restraints. This study demonstrates that PRE-derived distance restraints are useful in the determination of a high-resolution structure of a soluble protein when the number of NOE constraints is insufficient.

  1. High performance of solvothermally prepared VO2(B as anode for aqueous rechargeable lithium batteries

    Directory of Open Access Journals (Sweden)

    Milošević Sanja

    2015-01-01

    Full Text Available The VO2 (B was synthesized via a simple solvothermal route at 160oC in ethanol. The initial discharge capacity of VO2 (B anode, in saturated aqueous solution of LiNO3, was 177 mAh g-1 at a current rate of 50 mA g-1. After 50 cycles capacity fade was 4%, but from 20th-50th cycle no capacity drop was observed. The VO2 (B has shown very good cyclability at current rate of even 1000 mA g-1 with initial discharge capacity of 92 mAh g-1. The excellent electrochemical performance of VO2 (B was attributed to the stability of micro-nano structures to repeated intercalation /deintercalation process, very good electronic conductivity as well as the very low charge transfer resistance in the aqueous electrolyte. [Projekat Ministarstva nauke Republike Srbije, br. III45014

  2. Nano-structured textiles as high-performance aqueous cathodes for microbial fuel cells

    KAUST Repository

    Xie, Xing

    2011-01-01

    A carbon nanotube (CNT)-textile-Pt cathode for aqueous-cathode microbial fuel cells (MFCs) was prepared by electrochemically depositing Pt nanoparticles on a CNT-textile. An MFC equipped with a CNT-textile-Pt cathode revealed a 2.14-fold maximum power density with only 19.3% Pt loading, compared to that with a commercial Pt coated carbon cloth cathode. © 2011 The Royal Society of Chemistry.

  3. Soluble NCAM

    DEFF Research Database (Denmark)

    Secher, Thomas

    2008-01-01

    The neural cell adhesion molecule (NCAM) is a membrane-bound glycoprotein involved in homophilic interactions that facilitate cell-cell adhesion. In addition to a number of membrane-bound isoforms, NCAM also exists in several soluble isoforms that have been identified in cerebrospinal fluid, bloo...

  4. Development of a new generation of waste form for entrapment and immobilization of highly volatile and soluble radionuclides.

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Mark Andrew; Bencoe, Denise Nora; Brinker, C. Jeffrey; Murphy, Andrew Wilson; Holt, Kathleen Caroline; Turnham, Rigney; Kruichak, Jessica Nicole; Tellez, Hernesto; Miller, Andy; Xiong, Yongliang; Pohl, Phillip Isabio; Ockwig, Nathan W.; Wang, Yifeng; Gao, Huizhen

    2010-09-01

    The United States is now re-assessing its nuclear waste disposal policy and re-evaluating the option of moving away from the current once-through open fuel cycle to a closed fuel cycle. In a closed fuel cycle, used fuels will be reprocessed and useful components such as uranium or transuranics will be recovered for reuse. During this process, a variety of waste streams will be generated. Immobilizing these waste streams into appropriate waste forms for either interim storage or long-term disposal is technically challenging. Highly volatile or soluble radionuclides such as iodine ({sup 129}I) and technetium ({sup 99}Tc) are particularly problematic, because both have long half-lives and can exist as gaseous or anionic species that are highly soluble and poorly sorbed by natural materials. Under the support of Sandia National Laboratories (SNL) Laboratory-Directed Research & Development (LDRD), we have developed a suite of inorganic nanocomposite materials (SNL-NCP) that can effectively entrap various radionuclides, especially for {sup 129}I and {sup 99}Tc. In particular, these materials have high sorption capabilities for iodine gas. After the sorption of radionuclides, these materials can be directly converted into nanostructured waste forms. This new generation of waste forms incorporates radionuclides as nano-scale inclusions in a host matrix and thus effectively relaxes the constraint of crystal structure on waste loadings. Therefore, the new waste forms have an unprecedented flexibility to accommodate a wide range of radionuclides with high waste loadings and low leaching rates. Specifically, we have developed a general route for synthesizing nanoporous metal oxides from inexpensive inorganic precursors. More than 300 materials have been synthesized and characterized with x-ray diffraction (XRD), BET surface area measurements, and transmission electron microscope (TEM). The sorption capabilities of the synthesized materials have been quantified by using stable

  5. High sensitivity analysis of water-soluble, cyanine dye labeled proteins by high-performance liquid chromatography with fluorescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Qiao Xiaoqiang [CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Wang Li [State Key Laboratory of Fine Chemicals, Dalian University of Technology, 158 Zhongshan Road, Dalian 116012 (China); Ma Junfeng [CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Deng Qiliang; Liang Zhen [CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Zhang Lihua, E-mail: lihuazhang@dicp.ac.cn [CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Peng Xiaojun [State Key Laboratory of Fine Chemicals, Dalian University of Technology, 158 Zhongshan Road, Dalian 116012 (China); Zhang Yukui [CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China)

    2009-04-27

    A water-soluble sulfo-3H-indocyanine dye, the active N-hydroxysuccinimide ester of 3H-Indolium,1-[(4-carboxyphenyl)methyl]-2-[3-[1-[(4-carboxyphenyl)methyl] -1,3-dihydro-3,3-dimethyl-5-sulfo-2H-indol-2-ylidene]-1-propenyl] -3,3-dimethyl-5-sulfo-(9CI) (sb-cy3-NHS), containing two p-carboxybenzyl groups on nitrogen atoms, previously developed by our laboratory, was for the first time used for protein derivatization, followed by HPLC separation and fluorescence detection. With bovine serum albumin (BSA) as a model protein, effects of various experimental conditions, including denaturant concentration, reaction time and temperature, the pH value of buffer, and the molar ratio of fluorescence reagent to protein, on protein derivatization efficiency were systematically investigated. Under the optimal conditions, the limit of detection (LOD) for derivatized BSA was decreased to 12.8 nM, about 100-fold lower than that by UV and fluorescence detection with commercial fluorescein isothiocyanate (FITC) as labeling reagent. For HPLC analysis, an on-column excess fluorescence reagent depletion technique was developed based on the hydrophilicity of sb-cy3-NHS, which could avoid the interference on the analysis of target compounds. In addition, sb-cy3-NHS was applied for the derivatization of a three-protein mixture and egg white proteins. Compared to the results labeled by FITC, more proteins with low concentrations could be labeled by sb-cy3-NHS, resulting in improved detection sensitivity for protein analysis. All these results demonstrated that sb-cy3-NHS might be promising in detecting low abundance proteins, especially in the quantitative analysis of proteins.

  6. Stearic acid and high molecular weight PEO as matrix for the highly water soluble metoprolol tartrate in continuous twin-screw melt granulation.

    Science.gov (United States)

    Monteyne, Tinne; Adriaensens, Peter; Brouckaert, Davinia; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-10-15

    Granules with release-sustaining properties were developed by twin screw hot melt granulation (HMG) using a combination of stearic acid (SA) and high molecular weight polyethylene oxide (PEO) as matrix for a highly water soluble model drug, metoprolol tartrate (MPT). Earlier studies demonstrated that mixing molten SA and PEO resulted in hydrogen bond formation between hydroxyl groups of fatty acid molecules and ether groups in PEO chains. These molecular interactions might be beneficial in order to elevate the sustained release effect of drugs from a SA/PEO matrix. This study aims to investigate the continuous twin screw melt granulation technique to study the impact of a SA/PEO matrix on the dissolution rate of a highly water soluble drug (MPT). Decreasing the SA/PEO ratio improved the release-sustaining properties of the matrix. The solid state of the granules was characterized using differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and near infrared chemical imaging (NIR-CI) in order to understand the dissolution behavior. The results revealed a preferential interaction of the MPT molecules with stearic acid impeding the PEO to form hydrogen bonds with the stearic acid chains. However, this allowed the PEO chains to recrystallize inside the stearic acid matrix after granulation, hence, elevating the release-sustaining characteristics of the formulation.

  7. A Novel Proteomic Analysis of the Modifications Induced by High Hydrostatic Pressure on Hazelnut Water-Soluble Proteins

    Directory of Open Access Journals (Sweden)

    Nuria Prieto

    2014-05-01

    Full Text Available Food allergies to hazelnut represent an important health problem in industrialized countries because of their high prevalence and severity. Food allergenicity can be changed by several processing procedures since food proteins may undergo modifications which could alter immunoreactivity. High-hydrostatic pressure (HHP is an emerging processing technology used to develop novel and high-quality foods. The effect of HHP on allergenicity is currently being investigated through changes in protein structure. Our aim is to evaluate the effect of HHP on the protein profile of hazelnut immunoreactive extracts by comparative proteomic analysis with ProteomeLab PF-2D liquid chromatography and mass spectrometry. This protein fractionation method resolves proteins by isoelectric point and hydrophobicity in the first and second dimension, respectively. Second dimension chromatogram analyses show that some protein peaks present in unpressurized hazelnut must be unsolubilized and are not present in HHP-treated hazelnut extracts. Our results show that HHP treatment at low temperature induced marked changes on hazelnut water-soluble protein profile.

  8. A Novel Proteomic Analysis of the Modifications Induced by High Hydrostatic Pressure on Hazelnut Water-Soluble Proteins

    Science.gov (United States)

    Prieto, Nuria; Burbano, Carmen; Iniesto, Elisa; Rodríguez, Julia; Cabanillas, Beatriz; Crespo, Jesus F.; Pedrosa, Mercedes M.; Muzquiz, Mercedes; del Pozo, Juan Carlos; Linacero, Rosario; Cuadrado, Carmen

    2014-01-01

    Food allergies to hazelnut represent an important health problem in industrialized countries because of their high prevalence and severity. Food allergenicity can be changed by several processing procedures since food proteins may undergo modifications which could alter immunoreactivity. High-hydrostatic pressure (HHP) is an emerging processing technology used to develop novel and high-quality foods. The effect of HHP on allergenicity is currently being investigated through changes in protein structure. Our aim is to evaluate the effect of HHP on the protein profile of hazelnut immunoreactive extracts by comparative proteomic analysis with ProteomeLab PF-2D liquid chromatography and mass spectrometry. This protein fractionation method resolves proteins by isoelectric point and hydrophobicity in the first and second dimension, respectively. Second dimension chromatogram analyses show that some protein peaks present in unpressurized hazelnut must be unsolubilized and are not present in HHP-treated hazelnut extracts. Our results show that HHP treatment at low temperature induced marked changes on hazelnut water-soluble protein profile. PMID:28234319

  9. Amino acids recognition by water-soluble uncharged porphyrin tweezers: Spectroscopic evidences in high optical density solutions

    Energy Technology Data Exchange (ETDEWEB)

    Villari, Valentina, E-mail: villari@me.cnr.it [CNR-IPCF Istituto per i Processi Chimico-Fisici, V.le F. Stagno d' Alcontres 37, I-98158 Messina (Italy); Mineo, Placido, E-mail: gmineo@unict.it [CNR-IPCF Istituto per i Processi Chimico-Fisici, V.le F. Stagno d' Alcontres 37, I-98158 Messina (Italy); Dipartimento di Scienze Chimiche, Universita di Catania, Viale Andrea Doria 6, I-95125 Catania (Italy); Scamporrino, Emilio [Dipartimento di Scienze Chimiche, Universita di Catania, Viale Andrea Doria 6, I-95125 Catania (Italy); Micali, Norberto [CNR-IPCF Istituto per i Processi Chimico-Fisici, V.le F. Stagno d' Alcontres 37, I-98158 Messina (Italy)

    2012-06-19

    Highlights: Black-Right-Pointing-Pointer Molecular recognition properties of metal bis-porphyrins at high concentration. Black-Right-Pointing-Pointer The formation of the complex causes the disruption of the aggregates. Black-Right-Pointing-Pointer High sensitivity for the optical detection of low amount of amino acids. Black-Right-Pointing-Pointer Potential applications as a selective molecular sensor of amino acids. - Abstract: Small angle X-ray measurements on concentrated solutions of Cobalt-bis-porphyrins showed, at all the investigated concentration values, the presence of small aggregates which possess a sphere-like shape with a homogeneous electron density distribution. Such an aggregation, however, is proven not to affect the binding properties of the molecules with amino acids. Indeed, the Cobalt ion of the bis-porphyrins are available for coordinating the nitrogen atom of the amino acid to form a stable complex, as indicated by UV-vis and circular dichroism spectroscopy. The ability of these uncharged water-soluble bis-porphyrins to act as molecular sensors of amino acids in a wide concentration range takes great relevance in biosensing applications for which high concentration might be required.

  10. Coumarin-based 'turn-off' fluorescent chemosensor with high selectivity for Cu2+ in aqueous solution

    Science.gov (United States)

    Xu, Wen-Jun; Qi, De-Qiang; You, Jin-Zong; Hu, Fei-Fei; Bian, Jia-Ying; Yang, Chun-Xia; Huang, Juan

    2015-07-01

    Coumarin-based "turn-off" fluorescent chemosensor, 3-acetoacetyl-7-diethylaminocoumarin (1), has been synthesized and structurally characterized by IR, 1H NMR and X-ray crystal structure analysis. The fluorescence behaviors in the presence of various metal ions were investigated in aqueous media. 1 Exhibits highly selective and sensitive absorbance and fluorescence sensing ability for Cu2+ over other metal ions. Addition of Cu2+ to the aqueous solution of 1 gave rise to obvious absorbance change and fluorescence quenching. Other competing ions, such as Mg2+, Ba2+, Mn2+, Fe3+, Co2+, Ni2+, Zn2+, Pb2+, Cd2+, Hg2+, induced negligible absorbance and fluorescence changes under the same conditions. The job's plot showed that the stoichiometry between 1 and Cu2+ was estimated to be 1:1. The fluorescence intensity varied almost linearly vs. the concentration of Cu2+ (1.0-7.0 μM), and the detection limit of Cu2+ was estimated to be 1.81 nM, indicating that 1 can be used as "turn-off" fluorescent chemosensor to selectively detect Cu2+ in aqueous solution.

  11. Highly stable water-soluble platinum nanoparticles stabilized by hydrophilic N-heterocyclic carbenes.

    Science.gov (United States)

    Baquero, Edwin A; Tricard, Simon; Flores, Juan Carlos; de Jesús, Ernesto; Chaudret, Bruno

    2014-11-24

    Controlling the synthesis of stable metal nanoparticles in water is a current challenge in nanochemistry. The strategy presented herein uses sulfonated N-heterocyclic carbene (NHC) ligands to stabilize platinum nanoparticles (PtNPs) in water, under air, for an indefinite time period. The particles were prepared by thermal decomposition of a preformed molecular Pt complex containing the NHC ligand and were then purified by dialysis and characterized by TEM, high-resolution TEM, and spectroscopic techniques. Solid-state NMR studies showed coordination of the carbene ligands to the nanoparticle surface and allowed the determination of a (13)C-(195)Pt coupling constant for the first time in a nanosystem (940 Hz). Additionally, in one case a novel structure was formed in which platinum(II) NHC complexes form a second coordination sphere around the nanoparticle.

  12. PERMEABILITY, SOLUBILITY AND DIFFUSIVITY OF HYDROGEN ISOTOPES IN STAINLESS STEELS AT HIGH GAS PRESSURES

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, K; Michael Morgan, M

    2005-09-12

    The Defense Waste Processing Facility (DWPF) is about to process High Level Waste (HLW) Sludge Batch 4 (SB4). This sludge batch is high in alumina and nepheline can crystallize readily depending on the glass composition. Large concentrations of crystallized nepheline can have an adverse effect on HLW glass durability. Several studies have been performed to study the potential for nepheline formation in SB4. The Phase 3 Nepheline Formation study of SB4 glasses examined sixteen different glasses made with four different frits. Melt rate experiments were performed by the Process Science and Engineering Section (PS&E) of the Savannah River National Laboratory (SRNL) using the four frits from the Phase 3 work, plus additional high B2O3/high Fe2O3 frits. Preliminary results from these tests showed the potential for significant improvements in melt rate for SB4 glasses using a higher B2O3-containing frit, particularly Frit 503. The main objective of this study was to investigate the durability of SB4 glasses produced with a high B2O3 frit likely to be recommended for SB4 processing. In addition, a range of waste loadings (WLs) was selected to continue to assess the effectiveness of a nepheline discriminator in predicting concentrations of nepheline crystallization that would be sufficient to influence the durability response of the glass. Five glasses were selected for this study, covering a WL range of 30 to 50 wt% in 5 wt% increments. The Frit 503 glasses were batched and melted. Specimens of each glass were heat-treated to simulate cooling along the centerline of a DWPF-type canister (ccc) to gauge the effects of thermal history on product performance. Visual observations on both quenched and ccc glasses were documented. A representative sample from each glass was submitted to the SRNL Process Science Analytical Laboratory (PSAL) for chemical analysis to confirm that the as-fabricated glasses corresponded to the defined target compositions. The Product Consistency Test

  13. THE IMPACT OF TRACE ADDITIVES ON THE APPARENT SOLUBILITY OF HYDROGEN IN HEAVY OIL AND RELATED FEEDSTOCKS AT LOW AND HIGH TEMPERATURES

    Energy Technology Data Exchange (ETDEWEB)

    Jalal Abedi

    2002-09-01

    A systematic investigation was conducted to provide an accurate determination of hydrogen solubility in liquid media in temperatures in the range of 25-250 C and pressures in the range of 0.5-8 MPa. Results were obtained by an indirect gas solubility measurement method. The method was intended for use with high-resolution camera. The hydrogen solubility measurements were indirect and were based on pressure changes at constant temperature and measured volumes. Since the volume of the view cell was fixed the volume available for the vapor phase could be determined by measuring the location of the liquid-vapor interface. The interface was located to within the height of one pixel using high-resolution camera, which added {+-} 0.4 ml to the uncertainty of the vapor volume. Liquid-liquid interface locations were measured with equal precision. The accuracy of the method was illustrated through hydrogen solubility measurements in hexadecane and tetralin, which were in close agreement with the values available in the literature. Hydrogen solubilities in Athabasca bitumen vacuum bottoms (ABVB) were reported over a broad range of temperatures (80-250 C) and pressures (0.5-8 MPa).

  14. Laboratory evidence of organic peroxide and peroxyhemiacetal formation in the aqueous phase and implications for aqueous OH

    OpenAIRE

    Y. B. Lim; B. J. Turpin

    2015-01-01

    Aqueous chemistry in atmospheric waters (e.g., cloud droplets or wet aerosols) is considered a potentially important atmospheric pathway to produce secondary organic aerosol (SOAaq). Water-soluble organic compounds with small carbon numbers (C2–C3) are precursors for SOAaq; products include organic acids, organic sulfates, and high-molecular-weight compounds/oligomers. Fenton reactions and the uptake of gas-phase OH radicals are considered to be the major oxidant sources for...

  15. High-Throughput Excipient Discovery Enables Oral Delivery of Poorly Soluble Pharmaceuticals

    Science.gov (United States)

    2016-01-01

    Polymeric excipients are crucial ingredients in modern pills, increasing the therapeutic bioavailability, safety, stability, and accessibility of lifesaving products to combat diseases in developed and developing countries worldwide. Because many early-pipeline drugs are clinically intractable due to hydrophobicity and crystallinity, new solubilizing excipients can reposition successful and even failed compounds to more effective and inexpensive oral formulations. With assistance from high-throughput controlled polymerization and screening tools, we employed a strategic, molecular evolution approach to systematically modulate designer excipients based on the cyclic imide chemical groups of an important (yet relatively insoluble) drug phenytoin. In these acrylamide- and methacrylate-containing polymers, a synthon approach was employed: one monomer served as a precipitation inhibitor for phenytoin recrystallization, while the comonomer provided hydrophilicity. Systems that maintained drug supersaturation in amorphous solid dispersions were identified with molecular-level understanding of noncovalent interactions using NOESY and DOSY NMR spectroscopy. Poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) (poly(NIPAm-co-DMA)) at 70 mol % NIPAm exhibited the highest drug solubilization, in which phenytoin associated with inhibiting NIPAm units only with lowered diffusivity in solution. In vitro dissolution tests of select spray-dried dispersions corroborated the screening trends between polymer chemical composition and solubilization performance, where the best NIPAm/DMA polymer elevated the mean area-under-the-dissolution-curve by 21 times its crystalline state at 10 wt % drug loading. When administered to rats for pharmacokinetic evaluation, the same leading poly(NIPAm-co-DMA) formulation tripled the oral bioavailability compared to a leading commercial excipient, HPMCAS, and translated to a remarkable 23-fold improvement over crystalline phenytoin. PMID:27800558

  16. Maximal release of highly bifidogenic soluble dietary fibers from industrial potato pulp by minimal enzymatic treatment.

    Science.gov (United States)

    Thomassen, Lise V; Vigsnæs, Louise K; Licht, Tine R; Mikkelsen, Jørn D; Meyer, Anne S

    2011-05-01

    Potato pulp is a poorly utilized, high-volume co-processing product resulting from industrial potato starch manufacturing. Potato pulp mainly consists of the tuber plant cell wall material and is particularly rich in pectin, notably galactan branched rhamnogalacturonan I type pectin which has previously been shown to exhibit promising properties as dietary fiber. The objective of this study was to solubilize dietary fibers from potato pulp by a one-step minimal treatment procedure and evaluate the prebiotic potential of the fibers. Statistically designed experiments were conducted to investigate the influence of enzyme type, dosage, substrate level, incubation time, and temperature on the enzyme catalyzed solubilization to define the optimal minimal enzyme treatment for maximal fiber solubilization. The result was a method that within 1 min released 75% [weight/weight (w/w)] dry matter from 1% (w/w) potato pulp treated with 1.0% (w/w) [enzyme/substrate (E/S)] pectin lyase from Aspergillus nidulans and 1.0% (w/w) E/S polygalacturonase from Aspergillus aculeatus at pH 6.0 and 60 °C. Molecular size fractionation of the solubilized fibers revealed two major fractions: one fraction rich in galacturonic acid of 10-100 kDa indicating mainly homogalacturonan, and a fraction >100 kDa rich in galactose, presumably mainly made up of β-1,4-galactan chains of rhamnogalacturonan I. When fermented in vitro by microbial communities derived from fecal samples from three healthy human volunteers, both of the solubilized fiber fractions were more bifidogenic than fructo-oligosaccharides (FOS). Notably the fibers having molecular masses of >100 kDa selectively increased the densities of Bifidobacterium spp. and Lactobacillus spp. 2-3 times more than FOS.

  17. Colloidal Organolead Halide Perovskite with a High Mn Solubility Limit: A Step Toward Pb-Free Luminescent Quantum Dots.

    Science.gov (United States)

    Arunkumar, Paulraj; Gil, Kyeong Hun; Won, Seob; Unithrattil, Sanjith; Kim, Yoon Hwa; Kim, Ha Jun; Im, Won Bin

    2017-09-07

    Organolead halide perovskites have emerged as a promising optoelectronic material for lighting due to its high quantum yield, color-tunable, and narrow emission. Despite their unique properties, toxicity has intensified the search for ecofriendly alternatives through partial or complete replacement of lead. Herein, we report a room-temperature synthesized Mn(2+)-substituted 3D-organolead perovskite displacing ∼90% of lead, simultaneously retaining its unique excitonic emission, with an additional orange emission of Mn(2+) via energy transfer. A high Mn solubility limit of 90% was attained for the first time in lead halide perovskites, facilitated by the flexible organic cation (CH3NH3)(+) network, preserving the perovskite structure. The emission intensities of the exciton and Mn were influenced by the halide identity that regulates the energy transfer to Mn. Homogeneous emission and electron spin resonance characteristics of Mn(2+) indicate a uniform distribution of Mn. These results suggest that low-toxicity 3D-CH3NH3Pb1-xMnxBr3-(2x+1)Cl2x+1 nanocrystals may be exploited as magnetically doped quantum dots with unique optoelectronic properties.

  18. A continuous and highly effective static mixing process for antisolvent precipitation of nanoparticles of poorly water-soluble drugs.

    Science.gov (United States)

    Dong, Yuancai; Ng, Wai Kiong; Hu, Jun; Shen, Shoucang; Tan, Reginald B H

    2010-02-15

    Rapid and homogeneous mixing of the solvent and antisolvent is critical to achieve submicron drug particles by antisolvent precipitation technique. This work aims to develop a continuous and highly effective static mixing process for antisolvent precipitation of nanoparticles of poorly water-soluble drugs with spironolactone as a model drug. Continuous antisolvent production of drug nanoparticles was carried out with a SMV DN25 static mixer comprising 6-18 mixing elements. The total flow rate ranged from 1.0 to 3.0 L/min while the flow rate ratio of solvent to antisolvent was maintained at 1:9. It is found that only 6 mixing elements were sufficient to precipitate the particles in the submicron range. Increasing the number of elements would further reduce the precipitated particle size. Increasing flow rate from 1.0 to 3.0 L/min did not further reduce the particle size, while higher drug concentrations led to particle size increase. XRD and SEM results demonstrated that the freshly precipitated drug nanoparticles are in the amorphous state, which would, in presence of the mixture of solvent and antisolvent, change to crystalline form in short time. The lyophilized spironolactone nanoparticles with lactose as lyoprotectant possessed good redispersibility and showed 6.6 and 3.3 times faster dissolution rate than that of lyophilized raw drug formulation in 5 and 10 min, respectively. The developed static mixing process exhibits high potential for continuous and large-scale antisolvent precipitation of submicron drug particles.

  19. A polyamide receptor based benzothiazole derivative: highly selective and sensitive fluorescent sensor for Hg{sup 2+} ion in aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Maity, Shubhra Bikash; Bharadwaj, Parimal K., E-mail: pkb@iitk.ac.in

    2015-05-15

    A water soluble benzothiazole derivative having polyamide arms has been designed and synthesized. The sensor selectively detects Hg{sup 2+} ion in aqueous medium in presence of alkali, alkaline earth, first row transition metal and heavy metal ions. The reversible behaviour of the sensor can be achieved in presence of iodide ion. - Highlights: • A benzothiazole derivative having polyamide arms has been designed and synthesized. • It selectively detects Hg{sup 2+} ion in presence of host of monovalent, divalent and trivalent ions in aqueous medium. • It works through a reversible way. • The detection limit for Hg{sup 2+} ion was found to be 7.15×10{sup −7} M.

  20. Hypolipidemic and Antioxidative Effects of Aqueous Enzymatic Extract from Rice Bran in Rats Fed a High-Fat and -Cholesterol Diet

    Directory of Open Access Journals (Sweden)

    Yu-Xin Wang

    2014-09-01

    Full Text Available Purpose: The aqueous enzymatic extract from rice bran (AEERB was rich in protein, γ-oryzanol and tocols. The aim of this study was to investigate the effects of AEERB on the regulation of lipid metabolism and the inhibition of oxidative damage. Methods: The antioxidant activity of AEERB in vitro was measured in terms of radical scavenging capacity, ferric reducing ability power (FRAP and linoleic acid emulsion system-ferric thiocyanate method (FTC. Male Wistar rats were fed with a normal diet and a high-fat and high-cholesterol diet with or without AEERB. After treatment, biochemical assays of serum, liver and feces lipid levels, the antioxidant enzyme activity, malondialdehyde (MDA and protein carbonyl were determined. Result: AEERB is completely soluble in water and rich in hydrophilic and lipophilic functional ingredients. AEERB scavenged DPPH• and ABTS•+ and exhibited antioxidant activity slightly lower than that of ascorbic acid in the linoleic acid system. The administration of AEERB reduced serum lipid levels and the atherogenic index compared with those of the hyperlipidemic diet group (HD. The administration of AEERB significantly lowered liver lipid levels, inhibited hepatic 3-hydroxyl-3-methylglutaryl CoA reductase activity, and efficiently promoted the fecal excretion of total lipids and total cholesterol (TC (p < 0.05. Dietary AEERB enhanced antioxidant status in the serum, liver and brain by increasing the antioxidant enzyme activity of superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GSH-Px and decreasing the content of MDA and protein carbonyl. Conclusions: The results indicated that AEERB might act as a potent hypolipidemic and antioxidant functional food.

  1. Measurement of high carrier mobility in graphene in an aqueous electrolyte environment

    Science.gov (United States)

    Brown, Morgan A.; Crosser, Michael S.; Leyden, Matthew R.; Qi, Yabing; Minot, Ethan D.

    2016-08-01

    Graphene is a promising material for applications in aqueous electrolyte environments. To explore the impact of such environments on graphene's electrical properties, we performed Hall bar measurements on electrolyte-gated graphene. Assuming a Drude model, we find that the room temperature carrier mobility in water-gated, SiO2-supported graphene reaches 7000 cm2/Vs, comparable to the best dry SiO2-supported graphene devices. Our results show that the electrical performance of graphene is robust, even in the presence of dissolved ions that introduce an additional mechanism for Coulomb scattering.

  2. High-pressure infrared spectroscopy of ether- and ester-linked phosphatidylcholine aqueous dispersions.

    OpenAIRE

    Siminovitch, D J; Wong, P T; Mantsch, H H

    1987-01-01

    Infrared spectra of aqueous dispersions of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and its ether-linked analogue, 1,2-dihexadecyl-sn-glycero-3-phosphocholine (DHPC), were measured in a diamond anvil cell at 28 degrees C as a function of pressure up to 20 kbar. Although these two lipids differ only in the linkages to the saturated hydrocarbon chains, significant differences were observed in their barotropic behavior. Most notable were the magnitudes of the pressure-induced correlat...

  3. High-pressure infrared spectroscopy of ether- and ester-linked phosphatidylcholine aqueous dispersions.

    OpenAIRE

    Siminovitch, D. J.; Wong, P T; Mantsch, H. H.

    1987-01-01

    Infrared spectra of aqueous dispersions of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and its ether-linked analogue, 1,2-dihexadecyl-sn-glycero-3-phosphocholine (DHPC), were measured in a diamond anvil cell at 28 degrees C as a function of pressure up to 20 kbar. Although these two lipids differ only in the linkages to the saturated hydrocarbon chains, significant differences were observed in their barotropic behavior. Most notable were the magnitudes of the pressure-induced correlat...

  4. High-energy-density, aqueous, metal-polyiodide redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bin; Nie, Zimin; Wang, Wei; Liu, Jun; Sprenkle, Vincent L.

    2017-08-29

    Improved metal-based redox flow batteries (RFBs) can utilize a metal and a divalent cation of the metal (M.sup.2+) as an active redox couple for a first electrode and electrolyte, respectively, in a first half-cell. For example, the metal can be Zn. The RFBs can also utilize a second electrolyte having I.sup.-, anions of I.sub.x (for x.gtoreq.3), or both in an aqueous solution, wherein the I.sup.- and the anions of I.sub.x (for x.gtoreq.3) compose an active redox couple in a second half-cell.

  5. Soluble T cell receptor Vβ domains engineered for high-affinity binding to staphylococcal or streptococcal superantigens.

    Science.gov (United States)

    Sharma, Preeti; Wang, Ningyan; Kranz, David M

    2014-01-28

    Staphylococcus aureus and group A Streptococcus secrete a collection of toxins called superantigens (SAgs), so-called because they stimulate a large fraction of an individual's T cells. One consequence of this hyperactivity is massive cytokine release leading to severe tissue inflammation and, in some cases, systemic organ failure and death. The molecular basis of action involves the binding of the SAg to both a T cell receptor (TCR) on a T cell and a class II product of the major histocompatibility complex (MHC) on an antigen presenting cell. This cross-linking leads to aggregation of the TCR complex and signaling. A common feature of SAgs is that they bind with relatively low affinity to the variable region (V) of the beta chain of the TCR. Despite this low affinity binding, SAgs are very potent, as each T cell requires only a small fraction of their receptors to be bound in order to trigger cytokine release. To develop high-affinity agents that could neutralize the activity of SAgs, and facilitate the development of detection assays, soluble forms of the Vβ regions have been engineered to affinities that are up to 3 million-fold higher for the SAg. Over the past decade, six different Vβ regions against SAgs from S. aureus (SEA, SEB, SEC3, TSST-1) or S. pyogenes (SpeA and SpeC) have been engineered for high-affinity using yeast display and directed evolution. Here we review the engineering of these high-affinity Vβ proteins, structural features of the six different SAgs and the Vβ proteins, and the specific properties of the engineered Vβ regions that confer high-affinity and specificity for their SAg ligands.

  6. Soluble T Cell Receptor Vβ Domains Engineered for High-Affinity Binding to Staphylococcal or Streptococcal Superantigens

    Directory of Open Access Journals (Sweden)

    Preeti Sharma

    2014-01-01

    Full Text Available Staphylococcus aureus and group A Streptococcus secrete a collection of toxins called superantigens (SAgs, so-called because they stimulate a large fraction of an individual’s T cells. One consequence of this hyperactivity is massive cytokine release leading to severe tissue inflammation and, in some cases, systemic organ failure and death. The molecular basis of action involves the binding of the SAg to both a T cell receptor (TCR on a T cell and a class II product of the major histocompatibility complex (MHC on an antigen presenting cell. This cross-linking leads to aggregation of the TCR complex and signaling. A common feature of SAgs is that they bind with relatively low affinity to the variable region (V of the beta chain of the TCR. Despite this low affinity binding, SAgs are very potent, as each T cell requires only a small fraction of their receptors to be bound in order to trigger cytokine release. To develop high-affinity agents that could neutralize the activity of SAgs, and facilitate the development of detection assays, soluble forms of the Vβ regions have been engineered to affinities that are up to 3 million-fold higher for the SAg. Over the past decade, six different Vβ regions against SAgs from S. aureus (SEA, SEB, SEC3, TSST-1 or S. pyogenes (SpeA and SpeC have been engineered for high-affinity using yeast display and directed evolution. Here we review the engineering of these high-affinity Vβ proteins, structural features of the six different SAgs and the Vβ proteins, and the specific properties of the engineered Vβ regions that confer high-affinity and specificity for their SAg ligands.

  7. High resolution FT-ICR mass spectral analysis of bio-oil and residual water soluble organics produced by hydrothermal liquefaction of the marine microalga Nannochloropsis salina

    Energy Technology Data Exchange (ETDEWEB)

    Sudasinghe, Nilusha; Dungan, Barry; Lammers, Peter; Albrecht, Karl O.; Elliott, Douglas C.; Hallen, Richard T.; Schaub, Tanner

    2014-03-01

    We report a detailed compositional characterization of a bio-crude oil and aqueous by-product from hydrothermal liquefaction of Nannochloropsis salina by direct infusion Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) in both positive- and negative-ionization modes. The FT-ICR MS instrumentation approach facilitates direct assignment of elemental composition to >7000 resolved mass spectral peaks and three-dimensional mass spectral images for individual heteroatom classes highlight compositional diversity of the two samples and provide a baseline description of these materials. Aromatic nitrogen compounds and free fatty acids are predominant species observed in both the bio-oil and aqueous fraction. Residual organic compounds present in the aqueous fraction show distributions that are slightly lower in both molecular ring and/or double bond value and carbon number relative to those found in the bio-oil, albeit with a high degree of commonality between the two compositions.

  8. Effect of 20 % EDTA Aqueous Solution on Defective Tubes (Alloy600) in High Temperature Chemical Cleaning Environments

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyuk Chul [KHNP-CRI, Daejeon (Korea, Republic of)

    2016-04-15

    The transport and deposition of corrosion products in pressurized water nuclear reactor (PWR) steam generators have led to corrosion (SCC, denting etc.) problems. Lancing, mechanical cleaning and chemical cleaning have been used to reduce these problems. The methods of lancing and mechanical cleaning have limitations in removing corrosion products due to the structure of steam generator tubes. But high temperature chemical cleaning (HTCC) with EDTA is the most effective method to remove corrosion products regardless of the structure. However, EDTA in chemical cleaning aqueous solution and chemical cleaning environments affects the integrity of materials used in steam generators. The nuclear power plants have to perform the pre-test (also called as qualification test (QT)) that confirms the effect on the integrity of materials after HTCC. This is one of the series studies that assess the effect, and this study determines the effects of 20 % EDTA aqueous solution on defective tubes in high temperature chemical cleaning environments. The depth and magnitude of defects in steam generator (SG) tubes were measured by eddy current test (ECT) signals. Surface analysis and magnitude of defects were performed by using SEM/EDS. Corrosion rate was assessed by weight loss of specimens. The ECT signals (potential and depth %) of defective tubes increased marginally. But the lengths of defects, oxides on the surface and weights of specimens did not change. The average corrosion rate of standard corrosion specimens was negligible. But the surfaces on specimens showed traces of etching. The depth of etching showed a range on the nanometer. After comprehensive evaluation of all the results, it is concluded that 20 % EDTA aqueous solution in high temperature chemical cleaning environments does not have a negative effect on defective tubes.

  9. Gravimetric analysis of the solubility of methane in high boiling hydrocarbons and petroleum products; Gravimetrische Bestimmung der Loeslichkeit von Methan in hoeher siedenden Kohlenwasserstoffen und Erdoelprodukten

    Energy Technology Data Exchange (ETDEWEB)

    Laux, H.; Rahimian, I. [Institut fuer Erdoel- und Erdgasforschung, Clausthal-Zellerfeld (Germany)

    2001-05-01

    The solubility of methane has a great influence on the colloid stability of crude oils at the conditions of production. Adequate data are needed for the modelling of the beginning of asphaltene precipitation as the result of the destabilization. Because such data are limited in the literature a magnetic suspension balance was used. By means of the magnetic suspension balance the solubility of gases in high boiling products can be determined by the weight difference resulting from the steped pressure reduction. The solubility of methane was investigated in different n-alkanes and squalane as well as a wax, a slack wax, a extract from the solvent raffination and a atmospheric crude oil residue. The aim was to investigate the influence of the molare weight, the structure and the composition of mixture on the solubility of methane. The pressure was varied in the region to 120 bar, the temperature was predominantly 75 C. The influence of the temperature on the solubility of methane was studied in the slack wax and the atmospheric residue. The results and the advantage as well as the disadvantage of the using of the magnetic suspension balance will be discussed. (orig.)

  10. High efficiency aqueous and hybrid lithium-air batteries enabled by Li1.5Al0.5Ge1.5(PO4)3 ceramic anode-protecting membranes

    Science.gov (United States)

    Safanama, Dorsasadat; Adams, Stefan

    2017-02-01

    Due to their extremely high specific energy, rechargeable Li-air batteries could meet the demand for large-scale storage systems to integrate renewable sources into the power grid. Li-air batteries with aqueous catholytes with high solubility of discharge products have a higher potential to reach their slightly lower theoretical limits in practical devices. In this work, we demonstrate aqueous and hybrid Li-air batteries with NASICON-type Li1+xAxGe2-x(PO4)3 ceramic as anode-protecting membrane. The LAGP ceramic pellets with room temperature conductivity >10-4 S cm-1 are synthesized by melt quenching and subsequently annealed based on our optimized heat treatment cycle. Hybrid Li-air batteries are assembled by sandwiching LAGP membranes between Li-anode chamber and catholyte solutions (of various pH values) with CNT/Pt as air-cathode. When the two electron reduction mechanism prevails, overpotentials below 0.2 V are achieved for currents up to 0.07 mA cm-2 leading to energy efficiencies exceeding 98%.

  11. Analysis of SSLP and Soluble Protein Contents in Leaves of Mutants Induced by High Pressure in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    HEXiu-ying; XuShi-ping; LIAoYao-ping; MAOXing-xue; WENGKe-nan; CHENZhao-ming; CHENYue-han; XIAOWan-sheng

    2004-01-01

    Rice variety Yuexiangzhan and its mutants induced by high pressure were studied using microsatellite markers and soluble protein content analyses. Eleven of the 88 microsatellite primer pairs showed evident polymorphisms repeatedly, and the polymorphic frequencies wcrc 3.4-11.3% between the mutants and Yuexiangzhan. The polymorphic markers were randomly located on chromosomes. The more similar the plant types of the mutants like their original variety., the less polymorphic loci were detected. In addition, there was variation in the soluble protein contents among the leaves of mutants, and the contents were significantly lower than those of the original variety.

  12. Calculation of CO2,CH4 and H2S Solubilities in Aquenous Electrolyte Solution at High Prssure and High Temperature

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    This paper reports an investigation into the characterisation of liquid-vapor electrolyte solutions at high pressure and high temperature,A procedure to enable calculations of methane,carbon dioxide and hydrogen sulphide solubilities in brines(0-6m.) for temperature from 25 to 350℃ and for pressures from 1 to 1800 bar is presented.The model is based on Helgeson,Kirkham and Flowers modified equations of state(HKF)and on the semi-empirical interaction model introduced by Pitzer,HKF modified equations of state are used to calculate the reference fugacity of gas species,and the Pitzer ionic interaction model is used to calculate the activity coefficient of dissolved species(i.e.ionic or neutral).The efficiency of the combination of the two models is confirmed by several comparisons with data in the literature.

  13. Low toxic and high soluble camptothecin derivative 2–47 effectively induces apoptosis of tumor cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yao; Zhao, Hong-Ye; Jiang, Du; Wang, Lu-Yao; Xiang, Cen; Wen, Shao-Peng [Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, Sino-French Joint Laboratory of Food Nutrition, Safety and Medicinal Chemistry, Tianjin University of Science and Technology, Tianjin 300457 (China); Fan, Zhen-Chuan [Key Laboratory of Food Nutrition and Safety, Tianjin University of Science & Technology, Ministry of Education, Tianjin, 300457 (China); Obesita & Algaegen LLC, College Station, TX 77845 (United States); Zhang, Yong-Min [Université Pierre et Marie Curie-Paris 6, Institut Parisien de Chimie Moléculaire UMR CNRS 8232, 4 place Jussieu, 75005, Paris (France); Guo, Na [Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, Sino-French Joint Laboratory of Food Nutrition, Safety and Medicinal Chemistry, Tianjin University of Science and Technology, Tianjin 300457 (China); Teng, Yu-Ou, E-mail: tyo201485@tust.edu.cn [Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, Sino-French Joint Laboratory of Food Nutrition, Safety and Medicinal Chemistry, Tianjin University of Science and Technology, Tianjin 300457 (China); Yu, Peng, E-mail: yupeng@tust.edu.cn [Key Laboratory of Industrial Fermentation Microbiology, Tianjin Key Laboratory of Industrial Microbiology, Sino-French Joint Laboratory of Food Nutrition, Safety and Medicinal Chemistry, Tianjin University of Science and Technology, Tianjin 300457 (China)

    2016-04-08

    The cytotoxic activity of camptothecin derivatives is so high that these compounds need to be further modified before their successful application as anti-cancer agents clinically. In this study, we reported the synthesis and biological evaluation of a novel camptothecin derivative called compound 2–47. The changes in structure did not reduce its activity to inhibit DNA topoisomerase I. Compound 2–47 induced apoptosis of many tumor cells including leukemia cells K562, Jurkat, HL-60, breast cancer cell BT-549, colon cancer cell HT-29 and liver cancer cell HepG2 with a half maximal inhibitory concentration (IC{sub 50}) of 2- to 3-fold lower than HCPT as a control. In particular, 2–47 inhibited the proliferation of Jurkat cells with an IC{sub 50} of as low as 40 nM. By making use of Jurkat cell as a model, following treatment of Jurkat cells, compound 2–47 activated caspase-3 and PARP, resulting in a decreased Bcl-2/Bax ratio. These data showed that compound 2–47 induces Jurkat cell death through the mitochondrial apoptotic pathway. In addition, compound 2–47 showed a decreased cytotoxic activity against normal cells and an improved solubility in low-polar solvent. For example, compound 2–47 solutes in CHCl{sub 3} 130-fold higher than HCPT. Taken together, our data demonstrated that camptothecin derivative 2–47 notably inhibits the tumor cell proliferation through mitochondrial-mediated apoptosis in vitro. - Highlights: • Compound 2–47 showed a wide inhibitory effect on the tested tumor cell lines with an IC{sub 50} of 3 times lower than that of HCPT in general. • Compound 2–47 inhibited the proliferation of the human leukemia cell Jurkat at an IC{sub 50} of as low as 40 nM. • As compared to HCPT, compound 2–47 showed much reduced cytotoxicity on normal human cells. • As compared to others, compound 2–47 showed a hundreds-fold higher solubility in non-polar organic solution.

  14. Experimental evidence of bulk chemistry constraint on SiO2 solubility in clinopyroxene at high-pressure conditions

    Science.gov (United States)

    Kawasaki, Toshisuke; Osanai, Yasuhito

    2015-06-01

    We have experimentally confirmed that the solubility of SiO2 in clinopyroxene at ultrahigh-pressure metamorphic conditions is buffered by coesite and kyanite. The present findings were derived from high-pressure experiments on metapelite glass, powdered andesite and eclogite glass under anhydrous conditions. The metapelite glass and powdered andesite were recrystallised in boron nitride capsules at 8 GPa and 1100-1500 °C. The eclogite glass was heated in an AuPd capsule, both ends of which were welded, at 3 GPa and 1000 °C. Clinopyroxene nucleated from metapelite glass, the bulk composition of which is saturated in both SiO2 and Al2SiO5 components plotting within the Jd (Na,K)(Al,Cr)(Si,Ti)2O6-Qtz (Si,Ti)O2-Grt M3(Al,Cr)2(Si,Ti)3O12-Als (Al,Cr)2(Si,Ti)O5 tetrahedron (M = Fe, Mn, Mg, Ni, Zn, Ca), coexists with garnet, coesite and kyanite. The average excess silica content of the clinopyroxene ranges from 23.4 to 35.4 mol%. In contrast, an andesite experiment saturated in SiO2 but undersaturated in Al2SiO5 within the Jd-Qtz-Aug M(Si,Ti)O3-Grt tetrahedron produced clinopyroxene, garnet and coesite but no kyanite. The average excess silica in the clinopyroxene was 9.7-15.5 mol%, which is comparable to previous experimental data. Experiment on the eclogite glass with similar composition to andesite yielded clinopyroxene, garnet and coesite. An average excess silica content in clinopyroxene counts 6.4 mol%, which is much lower than that obtained from the andesite. The SiO2 content of clinopyroxene coexisting with garnet, coesite and kyanite is much higher than that of clinopyroxene coexisting with garnet and coesite without kyanite. Although the temperature dependence is unclear, the SiO2 solubility increases with pressure and Fe/(Fe+Mg). Clinopyroxene forms the solid solution series Jd-Es □0.5M0.5Al(Si,Ti)2O6 and Aug-Es, rather than Jd-Ts MAl2(Si,Ti)O6 and Es-Ts joins. Our experimental data suggest the probable existence of octahedral Si which may accompany the M2

  15. Copper(II) complexes with highly water-soluble L- and D-proline-thiosemicarbazone conjugates as potential inhibitors of Topoisomerase IIα.

    Science.gov (United States)

    Bacher, Felix; Enyedy, Éva A; Nagy, Nóra V; Rockenbauer, Antal; Bognár, Gabriella M; Trondl, Robert; Novak, Maria S; Klapproth, Erik; Kiss, Tamás; Arion, Vladimir B

    2013-08-05

    Two proline-thiosemicarbazone bioconjugates with excellent aqueous solubility, namely, 3-methyl-(S)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [L-Pro-FTSC or (S)-H2L] and 3-methyl-(R)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [D-Pro-FTSC or (R)-H2L], have been synthesized and characterized by elemental analysis, one- and two-dimensional (1)H and (13)C NMR spectroscopy, and electrospray ionization mass spectrometry. The complexation behavior of L-Pro-FTSC with copper(II) in an aqueous solution and in a 30% (w/w) dimethyl sulfoxide/water mixture has been studied via pH potentiometry, UV-vis spectrophotometry, electron paramagnetic resonance, (1)H NMR spectroscopy, and spectrofluorimetry. By the reaction of copper(II) acetate with (S)-H2L and (R)-H2L in water, the complexes [Cu(S,R)-L] and [Cu(R,S)-L] have been synthesized and comprehensively characterized. An X-ray diffraction study of [Cu(S,R)-L] showed the formation of a square-pyramidal complex, with the bioconjugate acting as a pentadentate ligand. Both copper(II) complexes displayed antiproliferative activity in CH1 ovarian carcinoma cells and inhibited Topoisomerase IIα activity in a DNA plasmid relaxation assay.

  16. Processing of high performance composites based on peek by aqueous suspension prepregging

    Directory of Open Access Journals (Sweden)

    Liliana Burakowski Nohara

    2010-06-01

    Full Text Available The use of polyamic acid (PAA precursor as interphase in polymer composites is one of the many applications of polyimides (PIs. In this work, composites based on poly(ether-ether-ketone (PEEK and carbon fibers were prepared using two manufacturing techniques for thermoplastic composites: hot compression molding, and aqueous polymeric suspension prepregging using PIs as interphase. Two PAAs were synthesized and used as interphases: 3,3'-4,4'-benzophenonetetracarboxylic dianhydride/oxydianiline (BTDA/ODA and pyromellitic dianhydride/oxydianiline (PMDA/ODA. The PAA/PI systems were analyzed by differential scanning calorimetry (DSC, thermogravimetry (TGA, Fourier transform infrared spectroscopy (FTIR and nuclear magnetic resonance (NMR. Results from these analyses confirmed the synthesis of these compounds. Aqueous polymeric suspension prepregging was more efficient than hot compression molding when the PMDA/ODA PAA/PI interphase was used; also, the interlaminar shear strength of composites produced using this technique was 14.5% higher than the one produced using hot compression molding.

  17. Flexible Aqueous Lithium-Ion Battery with High Safety and Large Volumetric Energy Density.

    Science.gov (United States)

    Dong, Xiaoli; Chen, Long; Su, Xiuli; Wang, Yonggang; Xia, Yongyao

    2016-06-20

    A flexible and wearable aqueous lithium-ion battery is introduced based on spinel Li1.1 Mn2 O4 cathode and a carbon-coated NASICON-type LiTi2 (PO4 )3 anode (NASICON=sodium-ion super ionic conductor). Energy densities of 63 Wh kg(-1) or 124 mWh cm(-3) and power densities of 3 275 W kg(-1) or 11.1 W cm(-3) can be obtained, which are seven times larger than the largest reported till now. The full cell can keep its capacity without significant loss under different bending states, which shows excellent flexibility. Furthermore, two such flexible cells in series with an operation voltage of 4 V can be compatible with current nonaqueous Li-ion batteries. Therefore, such a flexible cell can potentially be put into practical applications for wearable electronics. In addition, a self-chargeable unit is realized by integrating a single flexible aqueous Li-ion battery with a commercial flexible solar cell, which may facilitate the long-time outdoor operation of flexible and wearable electronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. An Optimised Aqueous Extract of Phenolic Compounds from Bitter Melon with High Antioxidant Capacity

    Directory of Open Access Journals (Sweden)

    Sing Pei Tan

    2014-12-01

    Full Text Available Bitter melon (Momordica charantia L. is a tropical fruit claimed to have medicinal properties associated with its content of phenolic compounds (TPC. The aim of the study was to compare water with several organic solvents (acetone, butanol, methanol and 80% ethanol for its efficiency at extracting the TPC from freeze-dried bitter melon powder. The TPC of the extracts was measured using the Folin-Ciocalteu reagent and their antioxidant capacity (AC was evaluated using three assays. Before optimisation, the TPC and AC of the aqueous extract were 63% and 20% lower, respectively, than for the best organic solvent, 80% ethanol. However, after optimising for temperature (80 °C, time (5 min, water-to-powder ratio (40:1 mL/g, particle size (1 mm and the number of extractions of the same sample (1×, the TPC and the AC of the aqueous extract were equal or higher than for 80% ethanol. Furthermore, less solvent (40 mL water/g and less time (5 min were needed than was used for the 80% ethanol extract (100 mL/g for 1 h. Therefore, this study provides evidence to recommend the use of water as the solvent of choice for the extraction of the phenolic compounds and their associated antioxidant activities from bitter melon.

  19. Studies on the mechanism of efficient extraction of tea components by aqueous ethanol.

    Science.gov (United States)

    Hu, Ci-Jie; Gao, Ying; Liu, Yang; Zheng, Xin-Qiang; Ye, Jian-Hui; Liang, Yue-Rong; Lu, Jian-Liang

    2016-03-01

    Effect of solvent on the extraction yield and its relevant mechanism have been studied in this paper. Compared with extraction by water, catechins and caffeine could be easily extracted from green tea by aqueous ethanol, but hardly at all by absolute ethanol. Results of the vacuum-assisted extraction, solubility determination of EGCG and caffeine, as well as swelling ratio analysis of the infused leaves, indicated that an excellent leaf-matrix-swelling effect and high solubility of tea components might be the key mechanisms for high extraction efficiency by the aqueous ethanol. These mechanisms were further confirmed by the pre-swelling extraction. This is a first report on the mechanism of efficient extraction by aqueous organic solvent. Application of pre-swelling extraction is also discussed.

  20. Biological variation and reference intervals for circulating osteopontin, osteoprotegerin, total soluble receptor activator of nuclear factor kappa B ligand and high-sensitivity C-reactive protein

    DEFF Research Database (Denmark)

    Sennels, H P; Jacobsen, Søren; Jensen, T

    2007-01-01

    Objective. Monitoring inflammatory diseases and osteoclastogenesis with osteopontin (OPN), osteoprotegerin (OPG), total soluble receptor activator of nuclear factor kappa B ligand (total sRANKL) and high-sensitivity C-reactive protein (hsCRP) has recently attracted increased interest. The purpose...

  1. High-level soluble expression of the functional peptide derived from the C-terminal domain of the sea cucumber lysozyme and analysis of its antimicrobial activity

    Directory of Open Access Journals (Sweden)

    Lina Cong

    2014-11-01

    Conclusion: These results indicate that the expressed rSjLys-C is a highly soluble product and has a strong antimicrobial activity. Therefore, gaining a large quantity of biologically active rSjLys-C will be used for further biochemical and structural studies and provide a potential use in aquaculture and medicine.

  2. Solubility design leading to high figure of merit in low-cost Ce-CoSb3 skutterudites

    Science.gov (United States)

    Tang, Yinglu; Hanus, Riley; Chen, Sinn-wen; Snyder, G. Jeffrey

    2015-01-01

    CoSb3-based filled skutterudite has emerged as one of the most viable candidates for thermoelectric applications in automotive industry. However, the scale-up commercialization of such materials is still a challenge due to the scarcity and cost of constituent elements. Here we study Ce, the most earth abundant and low-cost rare earth element as a single-filling element and demonstrate that, by solubility design using a phase diagram approach, the filling fraction limit (FFL) x in CexCo4Sb12 can be increased more than twice the amount reported previously (x=0.09). This ultra-high FFL (x=0.20) enables the optimization of carrier concentration such that no additional filling elements are needed to produce a state of the art n-type skutterudite material with a zT value of 1.3 at 850 K before nano-structuring. The earth abundance and low cost of Ce would potentially facilitate a widespread application of skutterudites. PMID:26189943

  3. Solubility design leading to high figure of merit in low-cost Ce-CoSb3 skutterudites.

    Science.gov (United States)

    Tang, Yinglu; Hanus, Riley; Chen, Sinn-wen; Snyder, G Jeffrey

    2015-07-20

    CoSb3-based filled skutterudite has emerged as one of the most viable candidates for thermoelectric applications in automotive industry. However, the scale-up commercialization of such materials is still a challenge due to the scarcity and cost of constituent elements. Here we study Ce, the most earth abundant and low-cost rare earth element as a single-filling element and demonstrate that, by solubility design using a phase diagram approach, the filling fraction limit (FFL) x in CexCo4Sb12 can be increased more than twice the amount reported previously (x=0.09). This ultra-high FFL (x=0.20) enables the optimization of carrier concentration such that no additional filling elements are needed to produce a state of the art n-type skutterudite material with a zT value of 1.3 at 850 K before nano-structuring. The earth abundance and low cost of Ce would potentially facilitate a widespread application of skutterudites.

  4. VNARs: An Ancient and Unique Repertoire of Molecules That Deliver Small, Soluble, Stable and High Affinity Binders of Proteins

    Directory of Open Access Journals (Sweden)

    Caroline Barelle

    2015-09-01

    Full Text Available At 420 million years, the variable domain of New Antigen Receptors or VNARs are undoubtedly the oldest (and smallest antigen binding single domains identified in the vertebrate kingdom. Their role as an integral part of the adaptive immune system of sharks has been well established and has served to provide a greater understanding of the evolution of humoral immunity; their cellular components and processes as well as the underlying genetic organization and molecular control mechanisms. Intriguingly, unlike the variable domain of the camelid heavy chain antibodies or VHH, VNARs do not conform to all of the characteristic properties of classical antibodies with an ancestral origin that clearly distinguishes them from true immunoglobulin antibodies. However, this uniqueness of their origin only adds to their potential as next generation therapeutic biologics with their structural and functional attributes and commercial freedom all enhancing their profile and current success. In fact their small size, remarkable stability, molecular flexibility and solubility, together with their high affinity and selectivity for target, all reinforce the potential of these domains as drug candidates. The purpose of this review is to provide an overview of the existing basic biology of these unique domains, to highlight the drug-like properties of VNARs and describe current progress in their journey towards the clinic.

  5. Betaglycan has two independent domains required for high affinity TGF-β binding: proteolytic cleavage separates the domains and inactivates the neutralizing activity of the soluble receptor

    Science.gov (United States)

    Mendoza, Valentín; Vilchis-Landeros, M. Magdalena; Mendoza-Hernández, Guillermo; Huang, Tao; Villarreal, Maria M.; Hinck, Andrew P.; López-Casillas, Fernando; Montiel, Jose-Luis

    2009-01-01

    Summary Betaglycan is a co-receptor for members of the TGF-β superfamily. Mutagenesis has identified two ligand binding regions, one at the membrane-distal and the other at the membrane-proximal half of the betaglycan ectodomain. Here we show that partial plasmin digestion of soluble betaglycan produces two proteolysis-resistant fragments of 45 and 55 kDa, consistent with the predicted secondary structure, which indicates an intervening non-structured linker region separating the highly structured N- and C-terminal domains. Amino terminal sequencing indicates that the 45 and 55 kDa fragments correspond, respectively, to the membrane-distal and -proximal regions. Plasmin treatment of membrane betaglycan results in the production of equivalent proteolysis-resistant fragments. The 45 and 55 kDa fragments, as well as their recombinant soluble counterparts, Sol Δ10 and Sol Δ11, bind TGF-β, nonetheless, compared to intact soluble betaglycan, have severely diminished ability to block TGF-β activity. Surface plasmon resonance (SPR) analysis indicates that soluble betaglycan has Kds in the low nanomolar range for the three TGF-β isoforms, while those for Sol Δ10 and Sol Δ11 are 1 – 2 orders of magnitude higher. SPR analysis further shows that the Kds of Sol Δ11 are not changed in the presence of Sol Δ10, indicating that the high affinity of soluble betaglycan is a consequence of tethering of the domains together. Overall, these results, suggest that betaglycan ectodomain exhibits a bi-lobular structure in which each lobule folds independently, binds TGF-β through distinct non-overlapping interfaces, and that linker modification may be an approach to improve soluble betaglycan’s TGF-β neutralizing activity. PMID:19842711

  6. An ambient aqueous synthesis for highly dispersed and active Pd/C catalyst for formic acid electro-oxidation

    Science.gov (United States)

    Cheng, Niancai; Lv, Haifeng; Wang, Wei; Mu, Shichun; Pan, Mu; Marken, Frank

    An experimentally simple process is reported in aqueous solution and under ambient conditions to prepare highly dispersed and active Pd/C catalyst without the use of a stabilizing agent. The [Pd(NH 3) 4] 2+ ion is synthesized with gentle heating in aqueous ammonia solution without formation of Pd(OH) x complex intermediates. The adsorbed [Pd(NH 3) 4] 2+ on the surface of carbon (Vulcan XC-72) is reduced in situ to Pd nanoparticles by NaBH 4. The Pd/C catalyst obtained is characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that highly dispersed Pd/C catalyst with 20 wt.% Pd content and with an average Pd nanoparticle diameter of 4.3-4.7 nm could be obtained. The electrochemical measurements show that the Pd/C catalyst without stabilizer has a higher electro-oxidation activity for formic acid compared to that of a Pd/C catalyst prepared in a traditional high temperature polyol process in ethylene glycol.

  7. Oriented functionalization of natural hollow kapok fiber for highly efficient removal of toxic Hg(II from aqueous solution

    Directory of Open Access Journals (Sweden)

    Feng eWang

    2016-02-01

    Full Text Available Due to hollow and tubular structure, a natural kapok fiber (KF was used as the support and orientation matrix to control the polymerization of ethyleneglycol dimethacrylate (EGDMA and N-vinylimidazole (VIM along its inherent axial surface via a facile in situ rapid polymerization reaction in air atmosphere. The as-formed KF@VIM/EGDMA composite is featured with porous surface and rich N-containing functional groups for potential application as a highly efficient adsorbent for removal of toxic Hg(II from aqueous solution. The variables affecting the adsorption capacity were studied, including monomer ratio, external pH values, contact time, and initial Hg(II concentration. The pseudo-second-order equation and two adsorption isotherms including Langmuir and Freundlich equations were applied to determine the adsorption kinetics and adsorption capacity. The results show that the as-prepared KF@VIM/EGDMA composite has a maximum adsorption capacity of 697 mg/g to Hg(II, while no appreciable adsorption capacity can be found for KF itself. Given its intrinsic large lumen, faster adsorption kinetics (45 min are also expected and observed for KF@VIM/EGDMA. After a simple filtration, this adsorbent can be directly separated from the aqueous solution and then be regenerated for multi-cyclable utilization. During the adsorption process, the chemical complexing represents the main adsorption mechanism. As a naturally renewable KF, such a simple preparation method opens a new avenue to develop highly efficient and economically viable adsorbent for removal of toxic heavy metal from aqueous solution.

  8. Synthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanes

    KAUST Repository

    Kumar, Rajeev Ananda

    2014-03-25

    The polymerization of isobutylene (IB) to yield highly reactive polyisobutylene (HR PIB) with high exo-olefin content using GaCl3 or FeCl3·diisopropyl ether complexes has been previously reported.1 In an effort to further improve polymerization rates and exo-olefin content, we have studied ethylaluminum dichloride (EADC) complexes with diisopropyl ether, 2-chloroethyl ethyl ether (CEEE), and bis(2-chloroethyl) ether (CEE) as catalysts in conjunction with tert-butyl chloride as initiator in hexanes at different temperatures. All three complexes were readily soluble in hexanes. Polymerization, however, was only observed with CEE. At 0 °C polymerization was complete in 5 min at [t-BuCl] = [EADC·CEE] = 10 mM and resulted in PIB with ∼70% exo-olefin content. Studies on complexation using ATR FTIR and 1H NMR spectroscopy revealed that at 1:1 stoichiometry a small amount of EADC remains uncomplexed. By employing an excess of CEE, exo-olefin contents increased up to 90%, while polymerization rates decreased only slightly. With decreasing temperature, polymerization rates decreased while molecular weights as well as exo-olefin contents increased, suggesting that isomerization has a higher activation energy than β-proton abstraction. Density functional theory (DFT) studies on the Lewis acid·ether binding energies indicated a trend consistent with the polymerization results. The polymerization mechanism proposed previously for Lewis acid·ether complexes1 adequately explains all the findings. © 2014 American Chemical Society.

  9. Self-assembly of highly crystalline spherical BiVO 4 in aqueous solutions

    Science.gov (United States)

    Yang, Tao; Xia, Dingguo

    2009-10-01

    Spherical bismuth vanadate particles are self-assembled from aqueous Bi(NO 3) 3 and NH 4VO 3 solutions by adjusting pH and tuning the amount of surfactant sodium dodecyl sulfate (SDS) via facile hydrothermal method. The BiVO 4 samples were characterized by X-ray diffraction (XRD) and the peaks suited well with the pure phase monoclinic scheelite BiVO 4. Field emission scanning electron microscopy (SEM) showed the average size of the spherical particles was 5 μm and the assembling stages in the hydrothermal synthesis process were recorded. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) revealed the nanoparticles were single crystal. FT-IR spectroscopy test results demonstrated there was no SDS left in the samples. The mechanism of the self-assembling has also been proposed.

  10. Superoxide generated by pyrogallol reduces highly water-soluble tetrazolium salt to produce a soluble formazan: a simple assay for measuring superoxide anion radical scavenging activities of biological and abiological samples.

    Science.gov (United States)

    Xu, Chen; Liu, Shu; Liu, Zhiqiang; Song, Fengrui; Liu, Shuying

    2013-09-02

    Superoxide anion radical (O2(˙-)) plays an important role in several human diseases. The xanthine/xanthine oxidase system is frequently utilized to produce O2(˙-). However, false positive results are easily got by using this system. The common spectrophotometric probes for O2(˙-) are nitroblue tetrazolium (NBT) and cytochrome c. Nevertheless, the application of NBT method is limited because of the water-insolubility of NBT formazan and the assay using cytochrome c lacks sensitivity and is not suitable for microplate measurement. We overcome these problems by using 1,2,3-trihydroxybenzene (pyrogallol) as O2(˙-)-generating system and a highly water-soluble tetrazolium salt, 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium sodium salt (WST-1) which can be reduced by superoxide anion radical to a stable water-soluble formazan with a high absorbance at 450 nm. The method is simple, rapid and sensitive. Moreover, it can be adapted to microplate format. In this study, the O2(˙-) scavenging activities of superoxide dismutase (SOD), L-ascorbic acid, N-acetyl-L-cysteine (NAC), albumin from human serum, flavonoids and herbal extracts were assessed by using this method. Meanwhile, the activities of tissue homogenates and serum were determined by using this validated method. This method, applicable to tissue homogenates, serum and herbal extracts, proved to be efficient for measuring O2(˙-) scavenging activities of biological and abiological samples.

  11. Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage

    Science.gov (United States)

    Shan, Xiaoqiang; Charles, Daniel S.; Lei, Yinkai; Qiao, Ruimin; Wang, Guofeng; Yang, Wanli; Feygenson, Mikhail; Su, Dong; Teng, Xiaowei

    2016-11-01

    Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost and environmental friendliness. However, their applications have been limited by a narrow potential window (~1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here we report the formation of layered Mn5O8 pseudocapacitor electrode material with a well-ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable potential window of 3.0 V in an aqueous electrolyte, as well as high energy and power performance, nearly 100% coulombic efficiency and 85% energy efficiency after 25,000 charge-discharge cycles. The interplay between hydroxylated interphase on the surface and the unique bivalence structure of Mn5O8 suppresses the gas evolution reactions, offers a two-electron charge transfer via Mn2+/Mn4+ redox couple, and provides facile pathway for Na-ion transport via intra-/inter-layer defects of Mn5O8.

  12. Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage.

    Science.gov (United States)

    Shan, Xiaoqiang; Charles, Daniel S; Lei, Yinkai; Qiao, Ruimin; Wang, Guofeng; Yang, Wanli; Feygenson, Mikhail; Su, Dong; Teng, Xiaowei

    2016-11-15

    Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost and environmental friendliness. However, their applications have been limited by a narrow potential window (∼1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here we report the formation of layered Mn5O8 pseudocapacitor electrode material with a well-ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable potential window of 3.0 V in an aqueous electrolyte, as well as high energy and power performance, nearly 100% coulombic efficiency and 85% energy efficiency after 25,000 charge-discharge cycles. The interplay between hydroxylated interphase on the surface and the unique bivalence structure of Mn5O8 suppresses the gas evolution reactions, offers a two-electron charge transfer via Mn(2+)/Mn(4+) redox couple, and provides facile pathway for Na-ion transport via intra-/inter-layer defects of Mn5O8.

  13. Soluble vs. insoluble fiber

    Science.gov (United States)

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

  14. n-Type Water/Alcohol-Soluble Naphthalene Diimide-Based Conjugated Polymers for High-Performance Polymer Solar Cells.

    Science.gov (United States)

    Wu, Zhihong; Sun, Chen; Dong, Sheng; Jiang, Xiao-Fang; Wu, Siping; Wu, Hongbin; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2016-02-17

    With the demonstration of small-area, single-junction polymer solar cells (PSCs) with power conversion efficiencies (PCEs) over the 10% performance milestone, the manufacturing of high-performance large-area PSC modules is becoming the most critical issue for commercial applications. However, materials and processes that are optimized for fabricating small-area devices may not be applicable for the production of high-performance large-area PSC modules. One of the challenges is to develop new conductive interfacial materials that can be easily processed with a wide range of thicknesses without significantly affecting the performance of the PSCs. Toward this goal, we report two novel naphthalene diimide-based, self-doped, n-type water/alcohol-soluble conjugated polymers (WSCPs) that can be processed with a broad thickness range of 5 to 100 nm as efficient electron transporting layers (ETLs) for high-performance PSCs. Space charge limited current and electron spin resonance spectroscopy studies confirm that the presence of amine or ammonium bromide groups on the side chains of the WSCP can n-dope PC71BM at the bulk heterojunction (BHJ)/ETL interface, which improves the electron extraction properties at the cathode. In addition, both amino functional groups can induce self-doping to the WSCPs, although by different doping mechanisms, which leads to highly conductive ETLs with reduced ohmic loss for electron transport and extraction. Ultimately, PSCs based on the self-doped WSCP ETLs exhibit significantly improved device performance, yielding PCEs as high as 9.7% and 10.11% for PTB7-Th/PC71BM and PffBT4T-2OD/PC71BM systems, respectively. More importantly, with PffBT4T-2OD/PC71BM BHJ as an active layer, a prominent PCE of over 8% was achieved even when a thick ETL of 100 nm was used. To the best of our knowledge, this is the highest efficiency demonstrated for PSCs with a thick interlayer and light-harvesting layer, which are important criteria for eventually making

  15. Modulation of aqueous precursor solution temperature for the fabrication of high-performance metal oxide thin-film transistors

    Science.gov (United States)

    Lee, Keun Ho; Park, Jee Ho; Yoo, Young Bum; Han, Sun Woong; Jong Lee, Se; Baik, Hong Koo

    2015-08-01

    In this study, we present a simple process for the fabrication of aqueous-solution-processed metal oxide thin-film transistors (TFTs) via the manipulation of precursor solution temperature. Indium oxide TFTs fabricated from a solution of indium nitrate at 4 °C exhibited the highest mobility of 2.73 cm2/(V·s) at an annealing temperature of 200 °C. When the temperature of the metal oxide precursor solution is 4 °C, metal cations within the solution can be fully surrounded by H2O molecules owing to the high dielectric constant of H2O at low temperatures. These metal complexes are advantageous for the conversion of metal oxides via thermally driven hydrolysis and condensation processes due to their high potential energies. The same techniques have been applied successfully with high-order metal oxides including indium zinc oxide, indium gallium oxide, and indium gallium zinc oxide.

  16. A Terbium Metal-Organic Framework for Highly Selective and Sensitive Luminescence Sensing of Hg(2+) Ions in Aqueous Solution.

    Science.gov (United States)

    Xia, Tifeng; Song, Tao; Zhang, Gege; Cui, Yuanjing; Yang, Yu; Wang, Zhiyu; Qian, Guodong

    2016-12-19

    A series of isomorphic lanthanide metal-organic frameworks (MOFs) Ln(TATAB)⋅(DMF)4 (H2 O)(MeOH)0.5 (LnTATAB, Ln=Eu, Tb, Sm, Dy, Gd; H3 TATAB=4,4',4''-s-triazine-1,3,5-triyltri-p-aminobenzoic acid) have been solvothermally synthesized and structurally characterized. Among these MOFs, TbTATAB exhibits good water stability and a high fluorescence quantum yield. Because mercury ions (Hg(2+) ) have a high affinity to nitrogen atoms, and the space between multiple nitrogen atoms from triazine and imino groups is suitable for interacting with Hg(2+) ions, TbTATAB shows highly selective and sensitive detection of Hg(2+) in aqueous solution with a detection limit of 4.4 nm. Furthermore, it was successfully applied to detect Hg(2+) ions in natural water samples. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. CYCLODEXTRIN INCLUSION COMPLEX TO ENHANCE SOLUBILITY OF POORLY WATER SOLUBLE DRUGS: A REVIEW

    Directory of Open Access Journals (Sweden)

    V.B. Chaudhary * 1 and J. K. Patel 2

    2013-01-01

    Full Text Available Low solubility compounds show dissolution rate limited absorption and hence poor absorption, distribution and target organ delivery. Improvement of aqueous solubility in such a case is valuable goal to improve therapeutic efficacy. Complexation with CDs by different methods like physical mixing, melting, kneding, spray drying, freeze drying, co-evaporation has been reported to enhance the solubility, dissolution rate and bioavability of poorly water soluble drugs. The formation of inclusion complex can be confirmed by DSC, FTIR, XRD and SEM study. This review aims to assess the use of cyclodextrines as complexing agents to enhance the solubility of poorly soluble drugs and hence to resolve the many issues associated with developing and commercializing poorly water soluble drugs.

  18. Supersaturation-nucleation behavior of poorly soluble drugs and its impact on the oral absorption of drugs in thermodynamically high-energy forms.

    Science.gov (United States)

    Ozaki, Shunsuke; Minamisono, Takuma; Yamashita, Taro; Kato, Takashi; Kushida, Ikuo

    2012-01-01

    In order to better understand the oral absorption behavior of poorly water-soluble drugs, their supersaturation-nucleation behavior was characterized in fasted state simulated intestinal fluid. The induction time (t(ind)) for nucleation was measured for four model drugs: itraconazole, erlotinib, troglitazone, and PLX4032. Supersaturated solutions were prepared by solvent shift method, and nucleation initiation was monitored by ultraviolet detection. The relationship between t(ind) and degree of supersaturation was analyzed in terms of classical nucleation theory. The defined supersaturation stability proved to be compound specific. Clinical data on oral absorption were investigated for drugs in thermodynamically high-energy forms such as amorphous forms and salts and was compared with in vitro supersaturation-nucleation characteristics. Solubility-limited maximum absorbable dose was proportionate to intestinal effective drug concentrations, which are related to supersaturation stability and thermodynamic solubility. Supersaturation stability was shown to be an important factor in determining the effect of high-energy forms. The characterization of supersaturation-nucleation behavior by the presented method is, therefore, valuable for assessing the potential absorbability of poorly water-soluble drugs. Copyright © 2011 Wiley-Liss, Inc.

  19. Determination of soluble dietary fibre content of Okara treated with high hydrostatic pressure and enzymes: a comparative evaluation of two methods (AOAC and HPLC-ELSD).

    Science.gov (United States)

    Pérez-López, E; Mateos-Aparicio, I; Rupérez, P

    2017-04-01

    Okara is a promising by-product from soybean and a rich source of dietary fibre, chiefly insoluble (IDF). To increase its solubility and functionality, a treatment with high hydrostatic pressure (HHP) assisted by food grade enzymes -Ultraflo(®) L or Viscozyme(®) L- has been performed. To monitor the effectiveness, an analysis of dietary fibre, mainly the soluble fraction (SDF), was accomplished by the AOAC enzymatic-gravimetric method with dialysis followed by both, spectrophotometric methods and High Performance Liquid Chromatography with Evaporative Light Scattering Detector (HPLC-ELSD) analysis of the soluble fraction. A significant increase in SDF (≈1.5-times) to the expense of a decrease in IDF was shown and chromatograms revealed two peaks of 95 and 22 kDa. Thus, treated Okara possessed a more balanced and convenient ratio of soluble to insoluble dietary fibre, which could have health benefits as prebiotic. Inbuilt interferences of the official AOAC's method for dietary fibre were confirmed and the direct HPLC-ELSD approach was about twice more sensitive than spectrophotometric methods. Consequently, the direct HPLC-ELSD analysis of the supernatant is proposed as a cheaper, faster and reliable method. Combined HHP-treatments plus specific enzymes represent a promising alternative for the valorisation and preservation of agrofood by-products.

  20. Oligo(ethylene glycol)-modified β-cyclodextrin-based polyrotaxanes for simultaneously modulating solubility and cellular internalization efficiency.

    Science.gov (United States)

    Tamura, Atsushi; Ohashi, Moe; Yui, Nobuhiko

    We developed stimuli-labile polyrotaxanes (PRXs) composed of β-cyclodextrin (β-CD), Pluronic as an axle polymer, and acid-cleavable N-triphenylmethyl groups as bulky stopper molecules, and found that the PRXs are potent therapeutics for Niemann-Pick type C disease, because the PRX can effectively reduce intracellular cholesterol through the intracellular release of threaded β-CDs. In general, the PRXs need to be chemically modified with hydrophilic functional groups because PRXs are not soluble in aqueous media. Herein, four series of oligo(ethylene glycol)s (OEGs) with different ethylene glycol repeating unit (2 or 3) and chemical structure of OEG terminal (hydroxy or methoxy) were modified onto the threaded β-CDs in PRX. The effects of the structure of OEG on the aqueous solubility, toxicity, and cellular internalization efficiency of OEG-modified PRXs were investigated to optimize the chemical structure of OEG. The hydroxy-terminated OEG-modified PRXs showed excellent solubility in aqueous media and no toxicity, regardless of the number of ethylene glycol repeating units. In the case of the methoxy-terminated OEG-modified PRXs, sufficient solubility in aqueous media and negligible toxicity were observed when the number of ethylene glycol repeating units was 3, while low solubility and toxicity were observed when the ethylene glycol repeating unit was 2. Additionally, cellular uptake levels of methoxy-terminated OEG-modified PRXs in RAW264.7 cells were higher than those of hydroxy-terminated OEG-modified PRXs. Consequently, the chemical structure of the OEG strongly affects the chemical and biological properties of the PRXs, and that a methoxy-terminated OEG with 3 ethylene glycol repeating units is the most preferable modification of PRXs, since the resultant PRX is sufficiently soluble in aqueous media, non-toxic, and possesses high cellular internalization efficiency.

  1. Equilibrium drug solubility measurements in 96-well plates reveal similar drug solubilities in phosphate buffer pH 6.8 and human intestinal fluid.

    Science.gov (United States)

    Heikkilä, Tiina; Karjalainen, Milja; Ojala, Krista; Partola, Kirsi; Lammert, Frank; Augustijns, Patrick; Urtti, Arto; Yliperttula, Marjo; Peltonen, Leena; Hirvonen, Jouni

    2011-02-28

    This study was conducted to develop a high throughput screening (HTS) method for the assessment of equilibrium solubility of drugs. Solid-state compounds were precipitated from methanol in 96-well plates, in order to eliminate the effect of co-solvent. Solubility of twenty model drugs was analyzed in water and aqueous solutions (pH 1.2 and 6.8) in 96-well plates and in shake-flasks (UV detection). The results obtained with the 96-well plate method correlated well (R(2)=0.93) between the shake-flask and 96-well plates over the wide concentration scale of 0.002-169.2mg/ml. Thereafter, the solubility tests in 96-well plates were performed using fasted state human intestinal fluid (HIF) from duodenum of healthy volunteers. The values of solubility were similar in phosphate buffer solution (pH 6.8) and HIF over the solubility range of 10(2)-10(5)μg/ml. The new 96-well plate method is useful for the screening of equilibrium drug solubility during the drug discovery process and it also allows the use of human intestinal fluid in solubility screening.

  2. Chemically amplified resist using self-solubility acceleration effect

    Science.gov (United States)

    Kihara, Naoko; Ushirogouchi, Tohru; Tada, Tsukasa; Naito, Takuya; Saito, Satoshi; Nakase, Makoto

    1994-11-01

    This paper concerns a novel three-component chemically amplified positive tone resist system for EB lithography composed of a novolak resin, an acid generator, and a newly synthesized dissolution inhibitor. To obtain resist materials with high sensitivity and high contrast, the authors synthesized four 1-(3H)-isobenzofuranone derivatives as novel dissolution inhibitors, which contain a tert-butoxycarbonyl (t-Boc) group and a lactone ring. The t-Boc group of these dissolution inhibitors was effectively decomposed by an acid catalyzed thermal reaction. In addition to this decomposition, the lactone ring of the decomposed product was spontaneously cleft in an aqueous base to generate carboxylic acid. Among these synthesized substances, only the t-Boc derivative of o-cresolphthalein, named CP-TBOC, showed an excellent solubility in 1-acetoxy-2-ethoxyethane. The subsequent cleavage in an aqueous developer was investigated by UV-visible spectroscopy.

  3. Soluble Urokinase-Type Plasminogen Activator Receptor Plasma Concentration May Predict Susceptibility to High Altitude Pulmonary Edema

    Science.gov (United States)

    Zügel, Stefanie; Schoeb, Michele; Auinger, Katja; Dehnert, Christoph; Maggiorini, Marco

    2016-01-01

    Introduction. Acute exposure to high altitude induces inflammation. However, the relationship between inflammation and high altitude related illness such as high altitude pulmonary edema (HAPE) and acute mountain sickness (AMS) is poorly understood. We tested if soluble urokinase-type plasminogen activator receptor (suPAR) plasma concentration, a prognostic factor for cardiovascular disease and marker for low grade activation of leukocytes, will predict susceptibility to HAPE and AMS. Methods. 41 healthy mountaineers were examined at sea level (SL, 446 m) and 24 h after rapid ascent to 4559 m (HA). 24/41 subjects had a history of HAPE and were thus considered HAPE-susceptible (HAPE-s). Out of the latter, 10/24 HAPE-s subjects were randomly chosen to suppress the inflammatory cascade with dexamethasone 8 mg bid 24 h prior to ascent. Results. Acute hypoxic exposure led to an acute inflammatory reaction represented by an increase in suPAR (1.9 ± 0.4 at SL versus 2.3 ± 0.5 at HA, p < 0.01), CRP (0.7 ± 0.5 at SL versus 3.6 ± 4.6 at HA, p < 0.01), and IL-6 (0.8 ± 0.4 at SL versus 3.3 ± 4.9 at HA, p < 0.01) in all subjects except those receiving dexamethasone. The ascent associated decrease in PaO2 correlated with the increase in IL-6 (r = 0.46, p < 0.001), but not suPAR (r = 0.27, p = 0.08); the increase in IL-6 was not correlated with suPAR (r = 0.16, p = 0.24). Baseline suPAR plasma concentration was higher in the HAPE-s group (2.0 ± 0.4 versus 1.8 ± 0.4, p = 0.04); no difference was found for CRP and IL-6 and for subjects developing AMS. Conclusion. High altitude exposure leads to an increase in suPAR plasma concentration, with the missing correlation between suPAR and IL-6 suggesting a cytokine independent, leukocyte mediated mechanism of low grade inflammation. The correlation between IL-6 and PaO2 suggests a direct effect of hypoxia, which is not the case for suPAR. However, suPAR plasma concentration measured before hypoxic exposure may predict

  4. Accumulation of soluble sugars in peel at high temperature leads to stay-green ripe banana fruit.

    Science.gov (United States)

    Yang, Xiaotang; Pang, Xuequn; Xu, Lanying; Fang, Ruiqiu; Huang, Xuemei; Guan, Peijian; Lu, Wangjin; Zhang, Zhaoqi

    2009-01-01

    Bananas (Musa acuminata, AAA group) fail to develop a yellow peel and stay green when ripening at temperatures >24 degrees C. The identification of the mechanisms leading to the development of stay-green ripe bananas has practical value and is helpful in revealing pathways involved in the regulation of chlorophyll (Chl) degradation. In the present study, the Chl degradation pathway was characterized and the progress of ripening and senescence was assessed in banana peel at 30 degrees C versus 20 degrees C, by monitoring relevant gene expression and ripening and senescence parameters. A marked reduction in the expression levels of the genes for Chl b reductase, SGR (Stay-green protein), and pheophorbide a oxygenase was detected for the fruit ripening at 30 degrees C, when compared with fruit at 20 degrees C, indicating that Chl degradation was repressed at 30 degrees C at various steps along the Chl catabolic pathway. The repressed Chl degradation was not due to delayed ripening and senescence, since the fruit at 30 degrees C displayed faster onset of various ripening and senescence symptoms, suggesting that the stay-green ripe bananas are of similar phenotype to type C stay-green mutants. Faster accumulation of high levels of fructose and glucose in the peel at 30 degrees C prompted investigation of the roles of soluble sugars in Chl degradation. In vitro incubation of detached pieces of banana peel showed that the pieces of peel stayed green when incubated with 150 mM glucose or fructose, but turned completely yellow in the absence of sugars or with 150 mM mannitol, at either 20 degrees C or 30 degrees C. The results suggest that accumulation of sugars in the peel induced by a temperature of 30 degrees C may be a major factor regulating Chl degradation independently of fruit senescence.

  5. Linking ileal digestible phosphorus and bone mineralization in broiler chickens fed diets supplemented with phytase and highly soluble calcium.

    Science.gov (United States)

    Adeola, O; Walk, C L

    2013-08-01

    The objectives of this study were to determine the ileal digestibility of P in potassium phosphate, phytase-related ileal digestible P release, bone-mineralization-based ileal digestible P equivalency of phytase, and phytase-related efficiency of ileal digestible P utilization for bone mineralization in broiler chickens at 2 dietary concentrations of highly soluble Ca (HSC). Birds were sorted by BW at d 15 posthatch and assigned to 8 cages per diet with 8 birds per cage. Twelve diets were arranged in a 2 × 6 factorial of HSC at 5 or 6 g/kg and P supply treatment at 6 levels consisting of 4 added P levels (P from KH2PO4 added at 0, 0.7, 1.4, or 2.1 g/kg of diet) or 2 added phytase levels (500 or 1,000 phytase units). On d 24 posthatch, ileal digesta were collected for ileal P digestibility (IPD) determination and the left tibia was collected from the 4 heaviest birds in each cage for bone ash determination. Weight gain, G:F, and tibia ash were higher (P phytase linearly increased (P phytase showed a reduction (P phytase intake indicated that 1,000 units of added phytase released 1.701 or 1.561 g of digestible P in diets containing 5 or 6 g of added HSC/kg, respectively. Polynomial regressions of tibia ash on digestible P or phytase intake in diets containing 5 or 6 g of added HSC/kg at 1,000 phytase units gave digestible P equivalency of 1.487 or 1.448 g, respectively. Thus, phytase-related efficiency of ileal digestible P utilization for bone mineralization was 87.4 and 92.8% in diets containing 5 or 6 g of added HSC/kg, respectively.

  6. A highly selective colorimetric and "turn-on" fluorimetric chemosensor for detecting CN- based on unsymmetrical azine derivatives in aqueous media

    Science.gov (United States)

    Sun, You; Hu, Jing-Han; Qi, Jing; Li, Jian-Bin

    2016-10-01

    A novel highly selective chemosensor S1 for cyanide based on unsymmetrical azine derivative was successfully designed and synthesized, which showed both colorimetric and fluorescence turn-on responses for cyanide ions in aqueous. This structurally simple chemosensor could detect CN- anion over other anions in aqueous solution DMSO/H2O (v/v = 3:2) undergo deprotonation reaction. Results showed that the chemosensor S1 exhibited 50 fold enhancement in fluorescence at 530 nm and showed an obvious change in color from colorless to yellow that could be detected by naked eye under the UV-lamp after the addition of CN- in aqueous solution. Moreover, the detection limit on fluorescence response of the sensor to CN- is down to 6.17 × 10- 8 M by titration method. Test strips based on S1 were obtain, which could be used as a convenient and efficient CN- test kit to detect CN- in aqueous solution.

  7. A comparative study on Ca content and distribution in two Gesneriaceae species reveals distinctive mechanisms to cope with high rhizospheric soluble calcium.

    Science.gov (United States)

    Li, Wenlong; Xu, Falun; Chen, Shixuan; Zhang, Zhennan; Zhao, Yan; Jin, Yukuan; Li, Meijing; Zhu, Yan; Liu, Yongxiu; Yang, Yi; Deng, Xin

    2014-01-01

    Excessive Ca is toxic to plants thus significantly affects plant growth and species distribution in Ca-rich karst areas. To understand how plants survive high Ca soil, laboratory experiments were established to compare the physiological responses and internal Ca distribution in organ, tissue, cell, and intracellular levels under different Ca levels for Lysionotus pauciflorus and Boea hygrometrica, two karst habitant Gesneriaceae species in Southwest China. In the controlled condition, L. pauciflorus could survive as high as 200 mM rhizospheric soluble Ca, attributed to a series of physiological responses and preferential storage that limited Ca accumulation in chloroplasts of palisade cells. In contrast, B. hygrometrica could survive only 20 mM rhizospheric soluble Ca, but accumulated a high level of internal Ca in both palisade and spongy cells without disturbance on photosynthetic activity. By phenotype screening of transgenic plants expressing high Ca-inducible genes from B. hygrometrica, the expression of BhDNAJC2 in A. thaliana was found to enhance plant growth and photosynthesis under high soluble Ca stress. BhDNAJC2 encodes a recently reported heat shock protein (HSP) 40 family DnaJ-domain protein. The Ca-resistant phenotype of BhDNAJC2 highlights the important role of chaperone-mediated protein quality control in Ca tolerance in B. hygrometrica. Taken together, our results revealed that distinctive mechanisms were employed in the two Gesneriaceae karst habitants to cope with a high Ca environment.

  8. A comparative study on Ca content and distribution in two Gesneriaceae species reveals distinctive mechanisms to cope with high rhizospheric soluble calcium

    Directory of Open Access Journals (Sweden)

    Wenlong eLi

    2014-11-01

    Full Text Available Excessive Ca is toxic to plants thus significantly affects plant growth and species distribution in Ca-rich karst areas. To understand how plants survive high Ca soil, laboratory experiments were established to compare the physiological responses and internal Ca distribution in organ, tissue, cell and intracellular levels under different Ca levels for Lysionotus pauciflorus and Boea hygrometrica, two karst habitant Gesneriaceae species in Southwest China. In the controlled condition, L. pauciflorus could survive as high as 200 mM rhizospheric soluble Ca, attributed to a series of physiological responses and preferential storage that limited Ca accumulation in chloroplasts of palisade cells. In contrast, B. hygrometrica could survive only 20 mM rhizospheric soluble Ca, but accumulated a high level of internal Ca in both palisade and spongy cells without disturbance on photosynthetic activity. By phenotype screening of transgenic plants expressing high Ca-inducible genes from B. hygrometrica, the expression of BhDNAJC2 in A. thaliana was found to enhance plant growth and photosynthesis under high soluble Ca stress. BhDNAJC2 encodes a recently reported heat shock protein (HSP 40 family DnaJ-domain protein. The Ca-resistant phenotype of BhDNAJC2 highlights the important role of chaperone-mediated protein quality control in Ca tolerance in B. hygrometrica. Taken together, our results revealed that distinctive mechanisms were employed in the two Gesneriaceae karst habitants to cope with a high Ca environment.

  9. Organic/Organic Cathode Bi-Interlayers Based on a Water-Soluble Nonconjugated Polymer and an Alcohol-Soluble Conjugated Polymer for High Efficiency Inverted Polymer Solar Cells.

    Science.gov (United States)

    Cai, Ping; Jia, Hongfu; Chen, Junwu; Cao, Yong

    2015-12-23

    In this work, organic/organic cathode bi-interlayers based on a water-soluble nonconjugated polymer PDMC and an alcohol-soluble conjugated polymer PFN were introduced to modifythe ITO cathode for inverted polymer solar cells (PSCs). PDMC with ultrahigh molecular weight would facilitate to form strong adsorption on the ITO substrate, while PFN could provide both compatibly interfacial contacts with the bottom PDMC interlayer and the upper organic active layer. The PDMC/PFN cathode bi-interlayers could decrease work function of the ITO cathode to 3.8 eV, supplying the most efficient ohmic interfacial contacts for electron collection at the ITO cathode. With a PTB7:PC71BM blend as the active layer, inverted PSCs based on the PDMC/PFN cathode bi-interlayers showed the highest efficiency of 9.01% and the best air stability within 60 days if compared with devices based on a separate PDMC or PFN cathode interlayer. The results suggest that the PDMC/PFN cathode bi-interlayers would play an important role to achieve high efficiency and stable inverted PSCs.

  10. Highly efficient removal of perfluorooctanoic acid from aqueous solution by H2O2-enhanced electrocoagulation-electroflotation technique

    Directory of Open Access Journals (Sweden)

    Bo Yang

    2016-03-01

    Full Text Available Electrocoagulation (EC technique was used to investigate the removal performance of aqueous perfluorooctanoic acid (PFOA with relatively high concentration as simulating the wastewater from organic fluorine industry. A comparison was done with the similar amount of coagulant between EC and chemical coagulation process. PFOA removal obtained was higher with EC process, especially for Fe anode. Several factors were studied to optimize the EC process. At the optimal operating parameters including 37.5 mA/cm2 of current density, initial pH 3.77, and 180 rpm of mixing speed, 93% of PFOA could be removed with 100 mg/L of initial concentration after 90-min electrolysis. Furthermore, the remove efficiency could be obviously improved by H2O2 intermittent addition, which removed more than 99% of PFOA within 40-min EC. It could be attributed to that H2O2 facilitated the oxidative transformation from ferrous to ferric ion. In addition, the adsorptive removal of aqueous PFOA on Fe flocs during EC was also verified by fourier transform infrared spectra.

  11. High accuracy thermal conductivity measurement of aqueous cryoprotective agents and semi-rigid biological tissues using a microfabricated thermal sensor.

    Science.gov (United States)

    Liang, Xin M; Sekar, Praveen K; Zhao, Gang; Zhou, Xiaoming; Shu, Zhiquan; Huang, Zhongping; Ding, Weiping; Zhang, Qingchuan; Gao, Dayong

    2015-05-20

    An improved thermal-needle approach for accurate and fast measurement of thermal conductivity of aqueous and soft biomaterials was developed using microfabricated thermal conductivity sensors. This microscopic measuring device was comprehensively characterized at temperatures from 0 °C to 40 °C. Despite the previous belief, system calibration constant was observed to be highly temperature-dependent. Dynamic thermal conductivity response during cooling (40 °C to -40 °C) was observed using the miniaturized single tip sensor for various concentrations of CPAs, i.e., glycerol, ethylene glycol and dimethyl sulfoxide. Chicken breast, chicken skin, porcine limb, and bovine liver were assayed to investigate the effect of anatomical heterogeneity on thermal conductivity using the arrayed multi-tip sensor at 20 °C. Experimental results revealed distinctive differences in localized thermal conductivity, which suggests the use of approximated or constant property values is expected to bring about results with largely inflated uncertainties when investigating bio-heat transfer mechanisms and/or performing sophisticated thermal modeling with complex biological tissues. Overall, the presented micro thermal sensor with automated data analysis algorithm is a promising approach for direct thermal conductivity measurement of aqueous solutions and soft biomaterials and is of great value to cryopreservation of tissues, hyperthermia or cryogenic, and other thermal-based clinical diagnostics and treatments.

  12. Aqueous and Template-Free Synthesis of Meso-Macroporous Polymers for Highly Selective Capture and Conversion of CO2.

    Science.gov (United States)

    Huang, Kuan; Liu, Fujian; Jiang, Lilong; Dai, Sheng

    2017-09-01

    Meso-macroporous polymers possessing nitrogen functionality were innovatively synthesized via an aqueous and template-free route in this work. Specifically, the polymerization of 1-(4-vinylbenzyl)-1,3,5,7-tetraazaadamantan-1-ium chloride in aqueous solutions under high temperatures induces the decomposition of hexamethylenetetramine unit into ammonia and formaldehyde molecules, followed by the cross-linking of benzene rings via "resol chemistry". During this process, extended meso-macroporous frameworks were constructed, and meanwhile active nitrogen species were incoporated. Taking the advantage of meso-macroporosity and nitrogen functionality, the synthesized polymers offer competitive CO2 capacities (0.37-1.58 mmol/g at 0˚C and 0.15 bar) and extraodinary CO2/N2 selectivities (155-324 at 0 ˚C). Furthermore, after complexed with metal ions, the synthesized polymers show excellent activity for catalyzing the cycloaddition of propylene oxide with CO2 (Yield>98.5%, TOF: 612.9-761.1 h-1). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Earth-like aqueous debris-flow activity on Mars at high orbital obliquity in the last million years.

    Science.gov (United States)

    de Haas, T; Hauber, E; Conway, S J; van Steijn, H; Johnsson, A; Kleinhans, M G

    2015-06-23

    Liquid water is currently extremely rare on Mars, but was more abundant during periods of high obliquity in the last few millions of years. This is testified by the widespread occurrence of mid-latitude gullies: small catchment-fan systems. However, there are no direct estimates of the amount and frequency of liquid water generation during these periods. Here we determine debris-flow size, frequency and associated water volumes in Istok crater, and show that debris flows occurred at Earth-like frequencies during high-obliquity periods in the last million years on Mars. Results further imply that local accumulations of snow/ice within gullies were much more voluminous than currently predicted; melting must have yielded centimetres of liquid water in catchments; and recent aqueous activity in some mid-latitude craters was much more frequent than previously anticipated.

  14. Removal of Pb2+ from aqueous solutions by a high-efficiency resin

    Science.gov (United States)

    Guo, Hao; Ren, Yongzheng; Sun, Xueliang; Xu, Yadi; Li, Xuemei; Zhang, Tiancheng; Kang, Jianxiong; Liu, Dongqi

    2013-10-01

    The removal of Pb2+ from aqueous solution by 732 cation-exchange resin in sodium type (732-CR) has been studied in batch experiments at varying pH (2.0-8.0), Pb2+ concentration (50-200 mg/L), contact time (5-300 min), temperature (288-308 K) and resin dose (0.125-0.75 g/L). The experimental data show that the ion-exchange process was dependent on pH and temperature, the optimal exchange capacity was found at pH 4.0, and higher temperature was beneficial to lead sorption. Kinetic data indicate that the ion-exchange process followed a pseudo-first order model. The equilibrium exchange capacity could be reached at approximately 4 h, and the maximum sorption capacity of Pb2+ at pH 4.0 was 396.8 mg/g resin. The equilibrium data were evaluated with Langmuir and Freundlich model, and were best fitted with Langmuir model. The thermodynamic parameters for removal of Pb2+ indicate that the reaction was spontaneous and endothermic. Additionally, column tests were conducted by using both synthetic solution and effluents from lead battery industry. The regeneration of resin was performed for two sorption-regeneration cycles by 1 M NaOH, and the results show that effective regeneration was achieved by this method.

  15. Inhibition of ice crystallisation in highly viscous aqueous organic acid droplets

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2008-09-01

    Full Text Available Homogeneous nucleation of ice within aqueous solution droplets and their subsequent crystallisation is thought to play a significant role in upper tropospheric ice cloud formation. It is normally assumed that homogeneous nucleation will take place at a threshold supersaturation, irrespective of the identity of the solute, and that rapid growth of ice particles will follow immediately after nucleation. However, it is shown here through laboratory experiments that droplets may not readily freeze in the very cold tropical tropopause layer (TTL, typical temperatures of 186–200 K. In these experiments ice crystal growth in citric acid solution droplets did not occur when ice nucleated below 197±6 K. Citric acid, 2-hydroxypropane-1,2,3-tricarboxyllic acid, is a molecule with similar functionality to oxygenated organic compounds which are ubiquitous in atmospheric aerosol. It is therefore thought to be a sensible proxy for atmospheric organic material. Evidence is presented that suggests citric acid solution droplets become ultra-viscous and form glassy solids under atmospherically relevant conditions. Diffusion of liquid water molecules to ice nuclei is expected to be very slow in ultra-viscous solution droplets and nucleation is negligible in glassy droplets; this most likely provides an explanation for the experimentally observed inhibition of ice crystallisation. The implications of ultra-viscous and glassy solution droplets for ice cloud formation and supersaturations in the TTL are discussed.

  16. Surface precipitation of highly porous hydrotalcite-like film on Al from a zinc aqueous solution.

    Science.gov (United States)

    Gao, Y F; Nagai, M; Masuda, Y; Sato, F; Seo, W S; Koumoto, K

    2006-04-11

    A hydrotalcite-like film has been successfully deposited on an Al-bearing glass substrate based on an interface reaction between an Al layer and a zinc aqueous solution. The film selectively grew on the Al surface but not on the glass surface. The film on Al was composed of layered nanosheets of a hydrotalcite-like compound containing Al and Zn. Comparably, deposits on the plastic surface and precipitates in solution were wurzite-type ZnO with various morphologies depending upon the preparation conditions. At low supersaturation degrees, single crystals and superstructures of Zn-Al hydrotalcite were also obtained. This porous hydrotalcite film has a potential application as catalyst supports, environmental materials, or matrixes for hydrotalcite-based nanocomposite films. Using Al as a reaction interface makes it easy to coat porous hydrotalcites on a series of matrix materials varying in shapes and properties, which is important for achieving practical applications. In addition, the method developed should be widely applicable to other systems for the preparation of porous or oriented hydrotalcite-like thin films by an appropriate combination of divalent/trivalent solution-substrate systems.

  17. Extraction and recovery of 2-butoxyethanol from aqueous phases containing high saline concentration

    Directory of Open Access Journals (Sweden)

    Katherine E. Manz

    2016-09-01

    Full Text Available Ethylene glycol monobutyl ether (EGBE, also known as 2-butoxyethanol (2-BE, has been identified as a contaminant in hydraulic fracturing fluids. In order to determine the presence of 2-BE in hydraulic fracturing chemical additives, a reliable method for recovering 2-BE from aqueous phases by liquid-liquid extraction combined with gas chromatography/mass spectrometry (GC/MS was established. The liquid-liquid extraction method was applied to samples matrices containing various amounts of salt. Using methylene chloride for liquid-liquid extraction in a sample to solvent ratio of 1:3, ≥99% 2-BE recovery may be achieved with less than 5% standard error. The limit of detection was determined to be 0.957 mg L−1 2-BE. Accuracy was determined to be 2.58% and precision was determined using the coefficient of variation, which was 3.5%. The method was used to recover 2-BE in a hydraulic fracturing chemical additive called Revert Flow and to quantify the weight percent of 2-BE in the chemical additive. Weight percent of two additional components of Revert Flow, D-limonene and 1-butoxy-2-propanol, were also determined. We also used the method to determine the abiotic of 2-BE in water, which was 5.55 days. The persistence of 2-BE in hydraulic fracturing fluid was also investigated and determined that 2-BE is more persistent in this environment.

  18. Inhibition of ice crystallisation in highly viscous aqueous organic acid droplets

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2008-05-01

    Full Text Available Homogeneous nucleation of ice within aqueous solution droplets and t