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Sample records for acidity soluble solids

  1. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... corresponding total soluble solids. 51.1178 Section 51.1178 Agriculture Regulations of the Department of... corresponding total soluble solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in relation to corresponding total soluble solids in the fruit is set forth in...

  2. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... corresponding total soluble solids. 51.1178 Section 51.1178 Agriculture Regulations of the Department of... corresponding total soluble solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in relation to corresponding total soluble solids in the fruit is set forth in...

  3. Enhancement of carvedilol solubility by solid dispersion technique using cyclodextrins, water soluble polymers and hydroxyl acid.

    PubMed

    Yuvaraja, K; Khanam, Jasmina

    2014-08-01

    Aim of the present work is to enhance aqueous solubility of carvedilol (CV) by solid dispersion technique using wide variety of carriers such as: β-cyclodextrin (βCD), hydroxypropyl-β-cyclodextrin (HPβCD), tartaric acid (TA), polyvinyl pyrrolidone K-30 (PVP K-30) and poloxamer-407 (PLX-407). Various products of 'CV-solid dispersion' had been studied extensively in various pH conditions to check enhancement of solubility and dissolution characteristics of carvedilol. Any physical change upon interaction between CV and carriers was confirmed by instrumental analysis: XRD, DSC, FTIR and SEM. Negative change of Gibb's free energy and complexation constants (Kc, 75-240M(-1), for cyclodextrins and 1111-20,365M(-1), for PVP K-30 and PLX-407) were the evidence of stable nature of the binding between CV and carriers. 'Solubility enhancement factor' of ionized-CV was found high enough (340 times) with HPβCD in presence of TA. TA increases the binding efficiency of cyclodextrin and changing the pH of microenvironment in dissolution medium. In addition, ionization process was used to increase the apparent intrinsic solubility of drug. In vitro, dissolution time of CV was remarkably reduced in the solid dispersion system compared to that of pure drug. This may be attributed to increased wettability, dispersing ability and transformation of crystalline state of drug to amorphous one.

  4. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... corresponding total soluble solids. 51.1178 Section 51.1178 Agriculture Regulations of the Department of... solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in relation to corresponding total soluble solids in the fruit is set forth in the following Table II...

  5. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... corresponding total soluble solids. 51.1178 Section 51.1178 Agriculture Regulations of the Department of... solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in relation to corresponding total soluble solids in the fruit is set forth in the following Table II...

  6. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... corresponding total soluble solids. 51.1178 Section 51.1178 Agriculture Regulations of the Department of... solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in relation to corresponding total soluble solids in the fruit is set forth in the following Table II...

  7. Stability and solubility enhancement of ellagic acid in cellulose ester solid dispersions.

    PubMed

    Li, Bin; Harich, Kim; Wegiel, Lindsay; Taylor, Lynne S; Edgar, Kevin J

    2013-02-15

    Structurally varied, carboxyl-containing cellulose derivatives were evaluated for their ability to form amorphous solid dispersions (ASD) with ellagic acid (EA), in order to improve the solubility of this high-melting, poorly bioavailable, but highly bioactive natural flavonoid compound. ASDs of EA with carboxymethylcellulose acetate butyrate (CMCAB), cellulose acetate adipate propionate (CAAdP), and hydroxypropylmethylcellulose acetate succinate (HPMCAS) were prepared, and EA dissolution from these ASDs was compared with that from pure crystalline EA and from EA/poly(vinylpyrrolidinone) (PVP) solid dispersions (SD). Polymer/drug mixtures were characterized by powder X-ray diffraction (XRPD), modulated differential scanning calorimetry (MDSC), nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). The XRPD and FT-IR results indicated that EA was amorphous in solid dispersions with EA concentration up to 25 wt%. The stability against crystallization and solution concentrations of EA from these solid dispersions were significantly higher than those observed for physical mixtures and pure crystalline EA. HPMCAS stabilized EA most effectively, among the polymers tested, against both chemical degradation and recrystallization. The relative ability to solubilize EA from ASDs at pH 6.8 was PVP>HPMCAS>CMCAB. EA dissolves from ASD in PVP quickly and completely (maximum 92%) at pH 6.8, but EA is also released from PVP at pH 1.2, and then crystallizes rapidly. Therefore PVP is not a practical candidate for EA ASD. In contrast, the cellulose derivative ASDs show very slow EA release at pH 1.2 (<4%) and faster but still incomplete drug release at pH 6.8 (maximum 35% for HPMCAS SD). The pH-triggered drug release from HPMCAS ASD makes HPMCAS a practical choice for EA solubility enhancement. PMID:23399175

  8. Cryomilling-induced solid dispersion of poor glass forming/poorly water-soluble mefenamic acid with polyvinylpyrrolidone K12.

    PubMed

    Kang, Naewon; Lee, Jangmi; Choi, Ji Na; Mao, Chen; Lee, Eun Hee

    2015-06-01

    The effect of mechanical impact on the polymorphic transformation of mefenamic acid (MFA) and the formation of a solid dispersion of mefenamic acid, a poor glass forming/poorly-water soluble compound, with polyvinylpyrrolidone (PVP) K12 was investigated. The implication of solid dispersion formation on solubility enhancement of MFA, prepared by cryomilling, was investigated. Solid state characterization was conducted using powder X-ray diffraction (PXRD) and Fourier-transform infrared (FTIR) spectroscopy combined with crystal structure analysis. Apparent solubility of the mixtures in pH 7.4 buffer was measured. A calculation to compare the powder patterns and FTIR spectra of solid dispersions with the corresponding physical mixtures was conducted. Solid state characterization showed that (1) MFA I transformed to MFA II when pure MFA I was cryogenically milled (CM); and (2) MFA forms a solid dispersion when MFA was cryogenically milled with PVP K12. FTIR spectral analysis showed that hydrogen bonding facilitated by mechanical impact played a major role in forming solid dispersions. The apparent solubility of MFA was significantly improved by making a solid dispersion with PVP K12 via cryomilling. This study highlights the importance of cryomilling with a good hydrogen bond forming excipient as a technique to prepare solid dispersion, especially when a compound shows a poor glass forming ability and therefore, is not easy to form amorphous forms by conventional method.

  9. Determination of soluble solids content and titratable acidity of intact fruit and juice of Satsuma mandarin using a hand-held NIR instrument in transmittance mode

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Determination of soluble solids content (SSC) and titratable acidity (TA) of intact fruit and juice of Satsuma mandarin was investigated using a hand-held NIR instrument “NIR-Gun” in transmittance mode. The resulting calibration equation measured SSC of intact fruit and juice with a standard error o...

  10. Production of a water-soluble fertilizer containing amino acids by solid-state fermentation of soybean meal and evaluation of its efficacy on the rapeseed growth.

    PubMed

    Wang, Jianlei; Liu, Zhemin; Wang, Yue; Cheng, Wen; Mou, Haijin

    2014-10-10

    Soybean meal is a by-product of soybean oil extraction and contains approximately 44% protein. We performed solid-state fermentation by using Bacillus subtilis strain N-2 to produce a water-soluble fertilizer containing amino acids. Strain N-2 produced a high yield of protease, which transformed the proteins in soybean meal into peptide and free amino acids that were dissolved in the fermentation products. Based on the Plackett-Burman design, the initial pH of the fermentation substrate, number of days of fermentation, and the ratio of liquid to soybean meal exhibited significant effects on the recovery of proteins in the resulting water-soluble solution. According to the predicted results of the central composite design, the highest recovery of soluble proteins (99.072%) was achieved at the optimum conditions. Under these conditions, the resulting solution contained 50.42% small peptides and 7.9% poly-γ-glutamic acid (γ-PGA). The water-soluble fertilizer robustly increased the activity of the rapeseed root system, chlorophyll content, leaf area, shoot dry weight, root length, and root weight at a concentration of 0.25% (w/v). This methodology offers a value-added use of soybean meal.

  11. AW-101 entrained solids - Solubility versus temperature

    SciTech Connect

    GJ Lumetta; RC Lettau; GF Piepel

    2000-03-31

    This report describes the results of a test conducted by Battelle to assess the solubility of the solids entrained in the diluted AW-101 low-activity waste (LAW) sample. BNFL requested Battelle to dilute the AW-1-1 sample using de-ionized water to mimic expected plant operating conditions. BNFL further requested Battelle to assess the solubility of the solids present in the diluted AW-101 sample versus temperature conditions of 30, 40, and 50 C. BNFL requested these tests to assess the composition of the LAW supernatant and solids versus expected plant-operating conditions. The work was conducted according to test plan BNFL-TP-29953-7, Rev. 0, Determination of the Solubility of LAW Entrained Solids. The test went according to plan, with no deviations from the test plan.

  12. Solid inclusion complexes of oleanolic acid with amino-appended β-cyclodextrins (ACDs): Preparation, characterization, water solubility and anticancer activity.

    PubMed

    Ren, Yufeng; Liu, Ying; Yang, Zhikuan; Niu, Raomei; Gao, Kai; Yang, Bo; Liao, Xiali; Zhang, Jihong

    2016-12-01

    Oleanolic acid (OA) is a pentacyclic triterpenoid acid of natural abundance in plants which possesses important biological activities. However, its medicinal applications were severely impeded by the poor water solubility and resultant low bioavailability and potency. In this work, studies on solid inclusion complexes of OA with a series of amino-appended β-cyclodextrins (ACDs) were conducted in order to address this issue. These complexes were prepared by suspension method and were well characterized by NMR, SEM, XRD, TG, DSC and Zeta potential measurement. The 2:1 inclusion mode of ACDs/OA complexes was elucidated by elaborate 2D NMR (ROESY). Besides, water solubility of OA was dramatically promoted by inclusion complexation with ACDs. Moreover, in vitro anticancer activities of OA against human cancer cell lines HepG2, HT29 and HCT116 were significantly enhanced after formation of inclusion complexes, while the apoptotic response results indicated their induction of apoptosis of cancer cells. This could provide a novel approach to development of novel pharmaceutical formulations of OA. PMID:27612690

  13. Nondestructive quantification of the soluble-solids content and the available acidity of apples by Fourier-transform near-infrared spectroscopy

    SciTech Connect

    Ying Yibin; Liu Yande; Tao Yang

    2005-09-01

    This research evaluated the feasibility of using Fourier-transform near-infrared (FT-NIR) spectroscopy to quantify the soluble-solids content (SSC) and the available acidity (VA) in intact apples. Partial least-squares calibration models, obtained from several preprocessing techniques (smoothing, derivative, etc.) in several wave-number ranges were compared. The best models were obtained with the high coefficient determination (r{sup 2}) 0.940 for the SSC and a moderate r{sup 2} of 0.801 for the VA, root-mean-square errors of prediction of 0.272% and 0.053%, and root-mean-square errors of calibration of 0.261% and 0.046%, respectively. The results indicate that the FT-NIR spectroscopy yields good predictions of the SSC and also showed the feasibility of using it to predict the VA of apples.

  14. Production of furfural from xylose, water-insoluble hemicelluloses and water-soluble fraction of corncob via a tin-loaded montmorillonite solid acid catalyst.

    PubMed

    Li, Huiling; Ren, Junli; Zhong, Linjie; Sun, Runcang; Liang, Lei

    2015-01-01

    The conversion of xylose, water-insoluble hemicelluloses (WIH) and water-soluble fraction (WSF) of corncob to furfural was performed using montmorillonite with tin ions (Sn-MMT) containing double acid sites as a solid acid catalyst. The co-existence of Lewis acids and Brønsted acids in Sn-MMT was shown to improve the furfural yield and selectivity. 76.79% furfural yield and 82.45% furfural selectivity were obtained from xylose using Sn-MMT as a catalyst in a biphasic system with 2-s-butylphenol (SBP) as the organic extracting layer and dimethyl sulfoxide (DMSO) as the co-solvent in contact with an aqueous phase saturated with NaCl (SBP/NaCl-DMSO) at 180°C for 30min. Furthermore, Sn-MMT also demonstrated the excellent catalytic performance in the conversion of pentose-rich materials of corncob and 39.56% and 54.15% furfural yields can be directly obtained from WIH and WSF in the SBP/NaCl-DMSO system, respectively.

  15. Production of furfural from xylose, water-insoluble hemicelluloses and water-soluble fraction of corncob via a tin-loaded montmorillonite solid acid catalyst.

    PubMed

    Li, Huiling; Ren, Junli; Zhong, Linjie; Sun, Runcang; Liang, Lei

    2015-01-01

    The conversion of xylose, water-insoluble hemicelluloses (WIH) and water-soluble fraction (WSF) of corncob to furfural was performed using montmorillonite with tin ions (Sn-MMT) containing double acid sites as a solid acid catalyst. The co-existence of Lewis acids and Brønsted acids in Sn-MMT was shown to improve the furfural yield and selectivity. 76.79% furfural yield and 82.45% furfural selectivity were obtained from xylose using Sn-MMT as a catalyst in a biphasic system with 2-s-butylphenol (SBP) as the organic extracting layer and dimethyl sulfoxide (DMSO) as the co-solvent in contact with an aqueous phase saturated with NaCl (SBP/NaCl-DMSO) at 180°C for 30min. Furthermore, Sn-MMT also demonstrated the excellent catalytic performance in the conversion of pentose-rich materials of corncob and 39.56% and 54.15% furfural yields can be directly obtained from WIH and WSF in the SBP/NaCl-DMSO system, respectively. PMID:25461009

  16. Factors affecting ethylene and carbon dioxide concentrations during ripening: Incidence on final dry matter, total soluble solids content and acidity of mango fruit.

    PubMed

    Nordey, Thibault; Léchaudel, Mathieu; Génard, Michel; Joas, Jacques

    2016-06-01

    Ripening of climacteric fruits is associated with pronounced changes in fruit gas composition caused by a concomitant rise in respiration and ethylene production. There is a discrepancy in the literature since some authors reported that changes in fruit gas compositions differ in attached and detached fruits. This study presents for the first time an overview of pre- and post-harvest factors that lead to variations in the climacteric respiration and ethylene production, and attempts to determine their impacts on fruit composition, i.e., dry matter, total soluble solids content and acidity. The impact of growing conditions such as the fruit position in the canopy and the fruit carbon supply; fruit detachment from the tree, including the maturity stage at harvest; and storage conditions after harvest, i.e., relative humidity and temperature were considered as well as changes in fruit skin resistance to gas diffusion during fruit growth and storage. Results showed that fruit gas composition vary with all pre and post-harvest factors studied. Although all mangoes underwent a respiratory climacteric and an autocatalytic ethylene production, whatever pre and post-harvest factors studied, large differences in ethylene production, climacteric respiration and fruit quality were measured. Results suggested that the ripening capacity is not related to the fruit ability to produce great amount of ethylene. In agreement with precedent studies, this work provided several lines of evidence that gas composition of fruit is related to its water balance. Our measurements indicated that skin resistance to gas diffusion increased after the harvest and during storage. It was so suggested that the faster ripening of detached fruit may be explained in part by changes in fruit water balance and skin resistance to gas diffusion caused by fruit detachment. PMID:27085177

  17. Factors affecting ethylene and carbon dioxide concentrations during ripening: Incidence on final dry matter, total soluble solids content and acidity of mango fruit.

    PubMed

    Nordey, Thibault; Léchaudel, Mathieu; Génard, Michel; Joas, Jacques

    2016-06-01

    Ripening of climacteric fruits is associated with pronounced changes in fruit gas composition caused by a concomitant rise in respiration and ethylene production. There is a discrepancy in the literature since some authors reported that changes in fruit gas compositions differ in attached and detached fruits. This study presents for the first time an overview of pre- and post-harvest factors that lead to variations in the climacteric respiration and ethylene production, and attempts to determine their impacts on fruit composition, i.e., dry matter, total soluble solids content and acidity. The impact of growing conditions such as the fruit position in the canopy and the fruit carbon supply; fruit detachment from the tree, including the maturity stage at harvest; and storage conditions after harvest, i.e., relative humidity and temperature were considered as well as changes in fruit skin resistance to gas diffusion during fruit growth and storage. Results showed that fruit gas composition vary with all pre and post-harvest factors studied. Although all mangoes underwent a respiratory climacteric and an autocatalytic ethylene production, whatever pre and post-harvest factors studied, large differences in ethylene production, climacteric respiration and fruit quality were measured. Results suggested that the ripening capacity is not related to the fruit ability to produce great amount of ethylene. In agreement with precedent studies, this work provided several lines of evidence that gas composition of fruit is related to its water balance. Our measurements indicated that skin resistance to gas diffusion increased after the harvest and during storage. It was so suggested that the faster ripening of detached fruit may be explained in part by changes in fruit water balance and skin resistance to gas diffusion caused by fruit detachment.

  18. Acid soluble, pepsin resistant platelet aggregating material

    SciTech Connect

    Schneider, M.D.

    1982-08-31

    Disclosed is an acid soluble, pepsin resistant, platelet aggregating material isolated from equine arterial tissue by extraction with dilute aqueous acid. The method of isolation and use to control bleeding are described. 4 figs.

  19. Acid-Soluble Material of Adenovirus

    PubMed Central

    Boulanger, P. A.; Jaume, F.; Flamencourt, P.; Biserte, G.

    1970-01-01

    Two methods are described for adenovirus capsid disruption and extraction of acid-soluble proteins from the viral core. The acid-soluble material of adenovirus consisted of three major proteins, one of them being selectively extracted after mild disruption of the virus particle. Some chemical properties of these proteins are reported. Images PMID:4986288

  20. Improvement in solubility of poor water-soluble drugs by solid dispersion

    PubMed Central

    Sareen, Swati; Mathew, George; Joseph, Lincy

    2012-01-01

    This article is intended to combine recent literature on solid dispersion technology for solubility enhancement with special emphasis on mechanism responsible for the same by solid dispersion, various preparation methods, and evaluation parameters. Solubility behavior is the most challenging aspect for various new chemical entities as 60% of the new potential products possess solubility problems. This is the biggest reason for new drug molecules not reaching to the market or not reaches to full potential. There are various techniques to enhance the drug solubility such as particle size reduction, nanosuspension, use of surfactants, salt formation, solid dispersion, etc. From this article it may be concluded that solid dispersion is an important approach for improvement of bioavailability of poor water-soluble drugs. PMID:23071955

  1. Ultrasound influence on the solubility of solid dispersions prepared for a poorly soluble drug.

    PubMed

    Pereira, Simone Vieira; Colombo, Fábio Belotti; de Freitas, Luis Alexandre Pedro

    2016-03-01

    Solid dispersions have been successfully used to enhance the solubility of several poorly water soluble drugs. Solid dispersions are produced by melting hydrophilic carriers and mixing in the poorly water soluble drug. Supersaturation is obtained by quickly cooling the mixture until it solidifies, thereby entrapping the drug. The effects of using ultrasound to homogenize the molten carrier and drug mixture were studied. In particular, the increase in drug solubility for the resulting solid dispersions was analyzed. Piroxicam, which has very low water solubility, was used as a model drug. A full factorial design was used to analyze how sonication parameters affected the solubility and in vitro release of the drug. The results show that the use of ultrasound can significantly increase the solubility and dissolution rate of the piroxicam solid dispersion. Pure piroxicam presented a solubility of 13.3 μg/mL. A maximum fourfold increase in solubility, reaching 53.8 μg/mL, was observed for a solid dispersion sonicated at 19 kHz for 10 min and 475 W. The in vitro dissolution rate test showed the sonicated solid dispersion reached a maximum rate of 18%/min, a sixfold increase over the piroxicam rate of 2.9%/min. Further solid state characterization by thermal, X-ray diffraction and Fourier transform infrared analyses also showed that the sonication process, in the described conditions, did not adversely alter the drug or significantly change its polymorphic form. Ultrasound is therefore an interesting technique to homogenize drug/carrier mixtures with the objective of increasing the solubility of drugs with poor water solubility. PMID:26548840

  2. Ultrasound influence on the solubility of solid dispersions prepared for a poorly soluble drug.

    PubMed

    Pereira, Simone Vieira; Colombo, Fábio Belotti; de Freitas, Luis Alexandre Pedro

    2016-03-01

    Solid dispersions have been successfully used to enhance the solubility of several poorly water soluble drugs. Solid dispersions are produced by melting hydrophilic carriers and mixing in the poorly water soluble drug. Supersaturation is obtained by quickly cooling the mixture until it solidifies, thereby entrapping the drug. The effects of using ultrasound to homogenize the molten carrier and drug mixture were studied. In particular, the increase in drug solubility for the resulting solid dispersions was analyzed. Piroxicam, which has very low water solubility, was used as a model drug. A full factorial design was used to analyze how sonication parameters affected the solubility and in vitro release of the drug. The results show that the use of ultrasound can significantly increase the solubility and dissolution rate of the piroxicam solid dispersion. Pure piroxicam presented a solubility of 13.3 μg/mL. A maximum fourfold increase in solubility, reaching 53.8 μg/mL, was observed for a solid dispersion sonicated at 19 kHz for 10 min and 475 W. The in vitro dissolution rate test showed the sonicated solid dispersion reached a maximum rate of 18%/min, a sixfold increase over the piroxicam rate of 2.9%/min. Further solid state characterization by thermal, X-ray diffraction and Fourier transform infrared analyses also showed that the sonication process, in the described conditions, did not adversely alter the drug or significantly change its polymorphic form. Ultrasound is therefore an interesting technique to homogenize drug/carrier mixtures with the objective of increasing the solubility of drugs with poor water solubility.

  3. Transformation of acidic poorly water soluble drugs into ionic liquids.

    PubMed

    Balk, Anja; Wiest, Johannes; Widmer, Toni; Galli, Bruno; Holzgrabe, Ulrike; Meinel, Lorenz

    2015-08-01

    Poor water solubility of active pharmaceutical ingredients (API) is a major challenge in drug development impairing bioavailability and therapeutic benefit. This study is addressing the possibility to tailor pharmaceutical and physical properties of APIs by transforming these into tetrabutylphosphonium (TBP) salts, including the generation of ionic liquids (IL). Therefore, poorly water soluble acidic APIs (Diclofenac, Ibuprofen, Ketoprofen, Naproxen, Sulfadiazine, Sulfamethoxazole, and Tolbutamide) were converted into TBP ILs or low melting salts and compared to the corresponding sodium salts. Free acids and TBP salts were characterized by NMR and IR spectroscopy, DSC and XRPD, DVS and dissolution rate measurements, release profiles, and saturation concentration measurements. TBP salts had lower melting points and glass transition temperatures and dissolution rates were improved up to a factor of 1000 as compared to the corresponding free acid. An increase in dissolution rates was at the expense of increased hygroscopicity. In conclusion, the creation of TBP ionic liquids or solid salts from APIs is a valuable concept addressing dissolution and solubility challenges of poorly water soluble acidic compounds. The data suggested that tailor-made counterions may substantially expand the formulation scientist's armamentarium to meet challenges of poorly water soluble drugs.

  4. Fundamental aspects of solid dispersion technology for poorly soluble drugs

    PubMed Central

    Huang, Yanbin; Dai, Wei-Guo

    2013-01-01

    The solid dispersion has become an established solubilization technology for poorly water soluble drugs. Since a solid dispersion is basically a drug–polymer two-component system, the drug–polymer interaction is the determining factor in its design and performance. In this review, we summarize our current understanding of solid dispersions both in the solid state and in dissolution, emphasizing the fundamental aspects of this important technology. PMID:26579360

  5. Fundamental aspects of solid dispersion technology for poorly soluble drugs.

    PubMed

    Huang, Yanbin; Dai, Wei-Guo

    2014-02-01

    The solid dispersion has become an established solubilization technology for poorly water soluble drugs. Since a solid dispersion is basically a drug-polymer two-component system, the drug-polymer interaction is the determining factor in its design and performance. In this review, we summarize our current understanding of solid dispersions both in the solid state and in dissolution, emphasizing the fundamental aspects of this important technology.

  6. Experimental measurement of solid solutes solubility in nanofluids

    NASA Astrophysics Data System (ADS)

    Fard, Manouchehr Manouchehrian; Beiki, Hossein

    2016-08-01

    The solubility of benzoic and salicylic acids was measured at a temperature range from 293 to 333 K in two types of water based nanofluids employed as the solvent. Silica and γ-alumina nanoparticles with volume concentrations of 0.025, 0.05, 0.1, 0.2 and 0.4 % were dispersed into de-ionized water as the based fluid. The results revealed that the solubility of nanofluid followed the same trend as pure water solubility with increasing temperature. At low temperatures, below 330 K for γ-Al2O3 nanofluids and 323 K for SiO2 nanofluids, nanoparticles had no effect on solubility, but by increasing the temperature, nanofluid solubility decreased. The maximum reduction in the solubility of compounds was observed at the temperature of 333 K and in 0.1 % γ-Alumina nanofluid and 0.025 % Silica nanofluids. Nanofluids solubility decreased up to a critical nanoparticles concentration while increased by increasing nanoparticles concentration further. The maximum reduction of nanofluids solubility at critical concentration was about 12.43 % for salicylic acid and 10.24 % for benzoic acid in 0.025 % SiO2 nanofluid. Nanofluids solubility was found to be strongly dependent on nanoparticles size. Bigger nanoparticles were more effective than smaller ones on nanofluids solubility.

  7. Solubility Enhancement of a Poorly Water Soluble Drug by Forming Solid Dispersions using Mechanochemical Activation

    PubMed Central

    Rojas-Oviedo, I.; Retchkiman-Corona, B.; Quirino-Barreda, C. T.; Cárdenas, J.; Schabes-Retchkiman, P. S.

    2012-01-01

    Mechanochemical activation is a practical cogrinding operation used to obtain a solid dispersion of a poorly water soluble drug through changes in the solid state molecular aggregation of drug-carrier mixtures and the formation of noncovalent interactions (hydrogen bonds) between two crystalline solids such as a soluble carrier, lactose, and a poorly soluble drug, indomethacin, in order to improve its solubility and dissolution rate. Samples of indomethacin and a physical mixture with a weight ratio of 1:1 of indomethacin and lactose were ground using a high speed vibrating ball mill. Particle size was determined by electron microscopy, the reduction of crystallinity was determined by calorimetry and transmission electron microscopy, infrared spectroscopy was used to find evidence of any interactions between the drug and the carrier and the determination of apparent solubility allowed for the corroboration of changes in solubility. Before grinding, scanning electron microscopy showed the drug and lactose to have an average particle size of around 50 and 30 μm, respectively. After high speed grinding, indomethacin and the mixture had a reduced average particle size of around 5 and 2 μm, respectively, showing a morphological change. The ground mixture produced a solid dispersion that had a loss of crystallinity that reached 81% after 30 min of grinding while the drug solubility of indomethacin within the solid dispersion increased by 2.76 fold as compared to the pure drug. Drug activation due to hydrogen bonds between the carboxylic group of the drug and the hydroxyl group of lactose as well as the decrease in crystallinity of the solid dispersion and the reduction of the particle size led to a better water solubility of indomethacin. PMID:23798775

  8. Solubility Enhancement of a Poorly Water Soluble Drug by Forming Solid Dispersions using Mechanochemical Activation.

    PubMed

    Rojas-Oviedo, I; Retchkiman-Corona, B; Quirino-Barreda, C T; Cárdenas, J; Schabes-Retchkiman, P S

    2012-11-01

    Mechanochemical activation is a practical cogrinding operation used to obtain a solid dispersion of a poorly water soluble drug through changes in the solid state molecular aggregation of drug-carrier mixtures and the formation of noncovalent interactions (hydrogen bonds) between two crystalline solids such as a soluble carrier, lactose, and a poorly soluble drug, indomethacin, in order to improve its solubility and dissolution rate. Samples of indomethacin and a physical mixture with a weight ratio of 1:1 of indomethacin and lactose were ground using a high speed vibrating ball mill. Particle size was determined by electron microscopy, the reduction of crystallinity was determined by calorimetry and transmission electron microscopy, infrared spectroscopy was used to find evidence of any interactions between the drug and the carrier and the determination of apparent solubility allowed for the corroboration of changes in solubility. Before grinding, scanning electron microscopy showed the drug and lactose to have an average particle size of around 50 and 30 μm, respectively. After high speed grinding, indomethacin and the mixture had a reduced average particle size of around 5 and 2 μm, respectively, showing a morphological change. The ground mixture produced a solid dispersion that had a loss of crystallinity that reached 81% after 30 min of grinding while the drug solubility of indomethacin within the solid dispersion increased by 2.76 fold as compared to the pure drug. Drug activation due to hydrogen bonds between the carboxylic group of the drug and the hydroxyl group of lactose as well as the decrease in crystallinity of the solid dispersion and the reduction of the particle size led to a better water solubility of indomethacin.

  9. Solubility of Sulfur Dioxide in Sulfuric Acid

    NASA Technical Reports Server (NTRS)

    Chang, K. K.; Compton, L. E.; Lawson, D. D.

    1982-01-01

    The solubility of sulfur dioxide in 50% (wt./wt.) sulfuric acid was evaluated by regular solution theory, and the results verified by experimental measurements in the temperature range of 25 C to 70 C at pressures of 60 to 200 PSIA. The percent (wt./wt.) of sulfur dioxide in 50% (wt./wt.) sulfuric acid is given by the equation %SO2 = 2.2350 + 0.0903P - 0.00026P 10 to the 2nd power with P in PSIA.

  10. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R. A.

    2012-03-12

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of Gd at 10

  11. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R.

    2012-02-22

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. For 6 M HNO{sub 3}, 10.5 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2 g/L and 0.25 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}.

  12. Joint solubility of samarium and dysprosium in solid magnesium

    NASA Astrophysics Data System (ADS)

    Rokhlin, L. L.; Dobatkina, T. V.; Lukyanova, E. A.; Korolkova, I. G.; Tarytina, I. E.

    2016-03-01

    The phase compositions of solid Mg-Sm-Dy alloys corresponding to the magnesium-corner region of the phase diagram are studied by optical and scanning electron microscopy, electrical resistivity measurements, and electron microprobe analysis. The obtained results allowed us to determine the joint solubility of samarium and dysprosium in solid magnesium at 500, 400, and 300°C; it decreases with decreasing temperature. The magnesium solid solution is found to be in equilibrium only with the Mg41Sm5 and Mg24Dy5 compounds, which are in equilibrium with the magnesium solid solution in the binary Mg-Sm and Mg-Dy systems.

  13. Solubility and thermodynamic properties of oxygen in solid molybdenum

    NASA Technical Reports Server (NTRS)

    Srivastava, S. C.; Seigle, L. L.

    1974-01-01

    A formula is obtained for the solubility of oxygen in solid Mo, determined in the range from 1400 to 1900 C by equilibrating rods of zone-refined Mo with mixtures of Mo and MoO2 powders. Using the known value of the free energy of formation of MoO2, a formula is obtained for the chemical potential of oxygen in the dilute solid solution. The heat of solution of oxygen in solid Mo and the excess entropy for the interstitial solid solution are also determined, assuming that the oxygen atoms reside in the octahedral interstices of bcc Mo.

  14. Effects of solids content, settling temperature, and liquor source on tall oil solubilities

    SciTech Connect

    Rousseau, R.W.; Kassebi, A.; Zinkel, D.F.

    1984-01-01

    Tall oil soap solubility in black liquors obtained from cooking pine and sweet gum, and in mixture of these liquors, was studied. As expected, solids content had a significant effect on the amount of soap remaining in settled liquors obtained from pine. Concentrating these liquors to about 30% solids reduced the soap concentration to approximately 0.8% of solids. Increasing the temperature at which the liquors were settled also increased residual tall oil soap content. Although mass balance calculations on mixtures of black liquors obtained from pine and gum show that the percentage recovery (solids basis) varies little with the inclusion of 12 to 50% hardwood black liquor, absolute recovery is increased with increased proportions of hardwood liquor. This is the result of decreased soap solubility with increased proportions of hardwood liquor. No discernable effect was observed on the proportion and composition of the acids and neutrals of the dissolved tall oil with respect to the solids content of the liquors.

  15. In vitro Dissolution Studies on Solid Dispersions of Mefenamic Acid

    PubMed Central

    Rao, K. R. S. Sambasiva; Nagabhushanam, M V; Chowdary, K. P. R.

    2011-01-01

    Solid dispersions of mefanamic acid with a water-soluble polymer polyvinyl pyrrolidine and a super disintegrant, primojel were prepared by common solvent and solvent evaporation methods employing methanol as the solvent. The dissolution rate and dissolution efficiency of the prepared solid dispersions were evaluated in comparison to the corresponding pure drug. Solid dispersions of mefenamic acid showed a marked enhancement in dissolution rate and dissolution efficiency. At 1:4 ratio of mefenamic acid-primojel a 2.61 fold increase in the dissolution rate of mefenamic acid was observed with solid dispersion. The solid dispersions in combined carriers gave much higher rates of dissolution than super disintegrants alone. Mefanamic acid-primojel-polyvinyl pyrrolidine (1:3.2:0.8) solid dispersion gave a 4.11 fold increase in the dissolution rate of mefenamic acid. Super disintegrants alone or in combination with polyvinyl pyrrolidine could be used to enhance the dissolution rate of mefenamic acid. PMID:22303074

  16. Water-soluble characteristics of chlorine in char derived from municipal solid wastes.

    PubMed

    Hwang, I H; Matsuto, T; Tanaka, N

    2006-01-01

    Chlorine in char derived from municipal solid waste (MSW) was characterized and quantified based on its water solubility: easily water-soluble, hardly water-soluble, and non-water-soluble chlorine. For that, a four-cycle process of water-washing, heating or carbonation were carried out. In order to confirm the characteristics of non-water-soluble chlorine, additional thermal treatment and an alkali-acid washing process were applied to washed char. It was found that a large particle size of char (0.5-1.0 mm) significantly contributed to the amount of non-water-soluble chlorine. Pulverization and HNO3-HF digestion were performed to identify a factor to interfere chlorine release from char with a large particle size. Pulverization was proven ineffective for release of non-water-soluble chlorine, whereas approximately 32% of non-water-soluble chlorine was extracted by HNO3-HF digestion. Therefore, the presence of non-water-soluble chlorine is likely to originate from its chemical property rather than simply from its physical one.

  17. Deliquescence: Hygroscopicity of Water-Soluble Crystalline Solids.

    PubMed

    Tereshchenko, Anatoly G

    2015-11-01

    A thermodynamic approach to the description of hygroscopic properties of crystal-soluble solids is introduced. Isotherms of water vapor sorption by a pure substance and the products with a heterogeneous or homogeneous impurity are compared. Solubility diagrams of substances in water are used to evaluate the influence of impurities on the hygroscopic properties of the products. Evidence demonstrates that water vapor sorption by a chemical product below the hygroscopic point of a basic component is determined by heterogeneous impurities. The introduction of the term "a hygroscopically pure substance" removes inconsistencies between the experimental results related to water vapor sorption and abstract theorems. The paper discusses relevant publications, concerning hygroscopicity of soluble substances, where the impurities are ignored resulting in procedural and theoretical errors.

  18. Solubilization of poorly water-soluble drugs using solid dispersions.

    PubMed

    Tran, Thao T-D; Tran, Phuong H-L; Khanh, Tran N; Van, Toi V; Lee, Beom-Jin

    2013-08-01

    Many new drugs have been discovered in pharmaceutical industry and exposed their surprised potential therapeutic effects. Unfortunately, these drugs possess low absorption and bioavailability since their solubility limitation in water. Solid dispersion (SD) is the current technique gaining so many attractions from scientists due to its effect on improving solubility and dissolution rate of poorly water-soluble drugs. A number of patents including the most recent inventions have been undertaken in this review to address various respects of this strategy in solubilization of poorly watersoluble drugs including type of carriers, preparation methods and view of technologies used to detect SD properties and mechanisms with the aim to accomplish a SD not only effective on enhanced bioavailability but also overcome difficulties associated with stability and production. Future prospects are as well discussed with an only hope that many developments and researches in this field will be successfully reached and contributed to commercial use for treatment as much as possible.

  19. Influences of heating temperature, pH, and soluble solids on the decimal reduction times of acid-adapted and non-adapted Escherichia coli O157:H7 (HCIPH 96055) in a defined liquid heating medium.

    PubMed

    Gabriel, Alonzo A

    2012-11-01

    The study characterized the influences of various combinations of process and product parameters namely, heating temperature (53, 55, 57.5, 60, 62 °C), pH (2.0, 3.0, 4.5, 6.0, 7.0), and soluble solids (SS) (1.4, 15, 35, 55, 69°Brix) on the thermal inactivation of non-adapted and acid-adapted E. coli O157:H7 (HCIPH 96055) in a defined liquid heating medium (LHM). Acid adaptation was conducted by propagating cells in a gradually acidifying nutrient broth medium, supplemented with 1% glucose. The D values of non-adapted cells ranged from 1.43 s (0.02 min) to 304.89 s (5.08 min). Acid-adapted cells had D values that ranged from 1.33 s (0.02 min) to 2628.57 s (43.81 min). Adaptation did not always result in more resistant cells as indicated by the Log (D(adapted)/D(non-adapted)) values calculated in all combinations tested, with values ranging from -1.10 to 1.40. The linear effects of temperature and pH, and the joint effects of pH and SS significantly influenced the thermal resistance of non-adapted cells. Only the linear and quadratic effects of both pH and SS significantly influenced the D values of acid-adapted cells. Generally, the D values of acid-adapted cells decreased at SS greater than 55 °Brix, suggesting the possible cancelation of thermal cross protection by acid habituation at such SS levels. The relatively wide ranges of LHM pH and SS values tested in the study allowed for better examination of the effects of these factors on the thermal death of the pathogen. The results established in this work may be used in the evaluation, control and improvement of safety of juice products; and of other liquid foods with physicochemical properties that fall within the ranges tested in this work. PMID:23141645

  20. Solubility of xenon in amino-acid solutions. II. Nine less-soluble amino acids

    NASA Astrophysics Data System (ADS)

    Kennan, Richard P.; Himm, Jeffrey F.; Pollack, Gerald L.

    1988-05-01

    Ostwald solubility (L) of xenon gas, as the radioisotope 133Xe, has been measured as a function of solute concentration, at 25.0 °C, in aqueous solutions of nine amino acids. The amino-acid concentrations investigated covered much of their solubility ranges in water, viz., asparagine monohydrate (0-0.19 M), cysteine (0-1.16 M), glutamine (0-0.22 M), histidine (0-0.26 M), isoleucine (0-0.19 M), methionine (0-0.22 M), serine (0-0.38 M), threonine (0-1.4 M), and valine (0-0.34 M). We have previously reported solubility results for aqueous solutions of six other, generally more soluble, amino acids (alanine, arginine, glycine, hydroxyproline, lysine, and proline), of sucrose and sodium chloride. In general, L decreases approximately linearly with increasing solute concentration in these solutions. If we postulate that the observed decreases in gas solubility are due to hydration, the results under some assumptions can be used to calculate hydration numbers (H), i.e., the number of H2O molecules associated with each amino-acid solute molecule. The average values of hydration number (H¯) obtained at 25.0 °C are 15.3±1.5 for asparagine, 6.8±0.3 for cysteine, 11.5±1.1 for glutamine, 7.3±0.7 for histidine, 5.9±0.4 for isoleucine, 10.6±0.8 for methionine, 11.2±1.3 for serine, 7.7± 1.0 for threonine, and 6.6±0.6 for valine. We have also measured the temperature dependence of solubility L(T) from 5-40 °C for arginine, glycine, and proline, and obtained hydration numbers H¯(T) in this range. Between 25-40 °C, arginine has an H¯ near zero. This may be evidence for an attractive interaction between xenon and arginine molecules in aqueous solution.

  1. Solid Lipid Nanoparticles of a Water Soluble Drug, Ciprofloxacin Hydrochloride

    PubMed Central

    Shah, M.; Agrawal, Y. K.; Garala, K.; Ramkishan, A.

    2012-01-01

    The aim of this study was to understand and investigate the relationship between experimental factors and their responses in the preparation of ciprofloxacin hydrochloride based solid lipid nanoparticles. A quadratic relationship was studied by developing central composite rotatable design. Amount of lipid and drug, stirring speed and stirring time were selected as experimental factors while particle size, zeta potential and drug entrapment were used as responses. Prior to the experimental design, a qualitative prescreening study was performed to check the effect of various solid lipids and their combinations. Results showed that changing the amount of lipid, stirring speed and stirring time had a noticeable influence on the entrapment efficiencies and particle size of the prepared solid lipid nanoparticles. The particle size of a solid lipid nanoparticle was in the range of 159-246 nm and drug encapsulation efficiencies were marginally improved by choosing a binary mixture of physically incompatible solid lipids. Release of ciprofloxacin hydrochloride from solid lipid nanoparticle was considerably slow, and it shows Higuchi matrix model as the best fitted model. Study of solid lipid nanoparticle suggested that the lipid based carrier system could potentially be exploited as a delivery system with improved drug entrapment efficiency and controlled drug release for water soluble actives. PMID:23716872

  2. Solid acids for green chemistry.

    PubMed

    Clark, James H

    2002-09-01

    Solid acids and especially those based on micelle-templated silicas and other mesoporous high surface area support materials are beginning to play a significant role in the greening of fine and specialty chemicals manufacturing processes. A wide range of important organic reactions can be efficiently catalyzed by these materials, which can be designed to provide different types of acidity as well as high degrees of reaction selectivity. The solid acids generally have high turnover numbers and can be easily separated from the organic components. The combination of this chemistry with innovative reaction engineering offers exciting opportunities for innovative green chemical manufacturing in the future. PMID:12234209

  3. Solid state stability and solubility of triethylenetetramine dihydrochloride.

    PubMed

    Henriet, Théo; Gana, Inès; Ghaddar, Carine; Barrio, Maria; Cartigny, Yohann; Yagoubi, Najet; Do, Bernard; Tamarit, Josep-Lluis; Rietveld, Ivo B

    2016-09-10

    The API triethylenetetramine dihydrochloride used as an alternative treatment of Wilson's disease is sensitive to water and it exhibits polymorphism. As this may become an issue for the drug formulation, the physical stability has been studied by differential scanning calorimetry, high-pressure thermal analysis, dynamic vapor sorption, and X-ray diffraction as a function of temperature. In addition, high-pressure liquid chromatography and mass spectrometry have been used to study the purity and chemical stability of the API. A pressure-temperature phase diagram of the pure compound has been constructed and it can be concluded that form II is monotropic in relation to form I, which is the only stable solid. The solubilities of the different solid forms have been determined with the help of a temperature - composition phase diagram. The API is very soluble, at 20° C about 10% of the saturated solution with respect to the dihydrate consists of API and the solubility of the pure form I is twice as high. Moreover, it has been shown that at 20°C, a relative humidity above 40% induces the formation of the dihydrate and at 70% a saturated solution appears. At higher temperatures, the formation of the dihydrate appears at lower relative humidity values. A clear link has been established between the API's chemical stability, its physical stability and the relative humidity in the air. Humidity levels above 40% are detrimental to the quality of the API. PMID:27377012

  4. Solid acids as fuel cell electrolytes.

    PubMed

    Haile, S M; Boysen, D A; Chisholm, C R; Merle, R B

    2001-04-19

    Fuel cells are attractive alternatives to combustion engines for electrical power generation because of their very high efficiencies and low pollution levels. Polymer electrolyte membrane fuel cells are generally considered to be the most viable approach for mobile applications. However, these membranes require humid operating conditions, which limit the temperature of operation to less than 100 degrees C; they are also permeable to methanol and hydrogen, which lowers fuel efficiency. Solid, inorganic, acid compounds (or simply, solid acids) such as CsHSO4 and Rb3H(SeO4)2 have been widely studied because of their high proton conductivities and phase-transition behaviour. For fuel-cell applications they offer the advantages of anhydrous proton transport and high-temperature stability (up to 250 degrees C). Until now, however, solid acids have not been considered viable fuel-cell electrolyte alternatives owing to their solubility in water and extreme ductility at raised temperatures (above approximately 125 degrees C). Here we show that a cell made of a CsHSO4 electrolyte membrane (about 1.5 mm thick) operating at 150-160 degrees C in a H2/O2 configuration exhibits promising electrochemical performances: open circuit voltages of 1.11 V and current densities of 44 mA cm-2 at short circuit. Moreover, the solid-acid properties were not affected by exposure to humid atmospheres. Although these initial results show promise for applications, the use of solid acids in fuel cells will require the development of fabrication techniques to reduce electrolyte thickness, and an assessment of possible sulphur reduction following prolonged exposure to hydrogen.

  5. The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.

    PubMed

    Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien

    2015-01-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15 mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20 mg/l) was broader than that of acid-soluble chitosan (4-8 mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water. PMID:25362971

  6. Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

    NASA Technical Reports Server (NTRS)

    Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

    1990-01-01

    The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

  7. Site specific solubility improvement using solid dispersions of HPMC-AS/HPC SSL--mixtures.

    PubMed

    Zecevic, Damir Elmar; Meier, Robin; Daniels, Rolf; Wagner, Karl-Gerhard

    2014-07-01

    Many upcoming drug candidates are pH-dependent poorly soluble weak bases in the pH range of the gastrointestinal tract. This often leads to a high in vivo variability and bioavailability issues. Aiming to overcome these limitations, the design of solid dispersions for site specific dissolution improvement or maintenance of a potent supersaturation over the entire gastro-intestinal pH-range, is proposed to assure a reliable drug therapy. Solid dispersions containing different ratios of Dipyridamole (DPD) or Griseofulvin (GRI) and the enteric polymer hydroxypropylmethylcellulose-acetate succinate (HPMC-AS) and the water soluble low-viscosity hydroxypropylcellulose (HPC-SSL) were prepared by hot melt extrusion (HME). The solid dispersions were evaluated for their solid state, dissolution characteristics applying a three pH-step dissolution method following an acidic to neutral pH transition and stability. The use of HPMC-AS in binary mixtures with DPD and GRI facilitated increased solubility and supersaturation at pH-controlled release of the preserved amorphous state of the dispersed drug, which even inverted the pH-dependent solubility profile of the weakly basic model drug (Dipyridamole). I.e. a potent site specific delivery system was created. With ternary solid dispersions of API, HPMC-AS and HPC-SSL, tailored release profiles with superior supersaturation over the applied pH-range could be obtained. At the same time, binary and ternary mixtures showed favorable stability properties at a temperature difference between glass transition temperature and the applied storage temperature of down to 16°C.

  8. Improvement in Aqueous Solubility of Retinoic Acid Receptor (RAR) Agonists by Bending the Molecular Structure.

    PubMed

    Hiramatsu, Michiaki; Ichikawa, Yuki; Tomoshige, Shusuke; Makishima, Makoto; Muranaka, Atsuya; Uchiyama, Masanobu; Yamaguchi, Takao; Hashimoto, Yuichi; Ishikawa, Minoru

    2016-08-01

    Aqueous solubility is a key requirement for many functional molecules, e. g., drug candidates. Decrease of the partition coefficient (log P) by chemical modification, i.e., introduction of hydrophilic group(s) into molecules, is a classical strategy for improving aqueous solubility. We have been investigating alternative strategies for improving the aqueous solubility of pharmaceutical compounds by disrupting intermolecular interactions. Here, we show that introducing a bend into the molecular structure of retinoic acid receptor (RAR) agonists by changing the substitution pattern from para to meta or ortho dramatically enhances aqueous solubility by up to 890-fold. We found that meta analogs exhibit similar hydrophobicity to the parent para compound, and have lower melting points, supporting the idea that the increase of aqueous solubility was due to decreased intermolecular interactions in the solid state as a result of the structural changes.

  9. Improvement in Aqueous Solubility of Retinoic Acid Receptor (RAR) Agonists by Bending the Molecular Structure.

    PubMed

    Hiramatsu, Michiaki; Ichikawa, Yuki; Tomoshige, Shusuke; Makishima, Makoto; Muranaka, Atsuya; Uchiyama, Masanobu; Yamaguchi, Takao; Hashimoto, Yuichi; Ishikawa, Minoru

    2016-08-01

    Aqueous solubility is a key requirement for many functional molecules, e. g., drug candidates. Decrease of the partition coefficient (log P) by chemical modification, i.e., introduction of hydrophilic group(s) into molecules, is a classical strategy for improving aqueous solubility. We have been investigating alternative strategies for improving the aqueous solubility of pharmaceutical compounds by disrupting intermolecular interactions. Here, we show that introducing a bend into the molecular structure of retinoic acid receptor (RAR) agonists by changing the substitution pattern from para to meta or ortho dramatically enhances aqueous solubility by up to 890-fold. We found that meta analogs exhibit similar hydrophobicity to the parent para compound, and have lower melting points, supporting the idea that the increase of aqueous solubility was due to decreased intermolecular interactions in the solid state as a result of the structural changes. PMID:27378357

  10. Water and acid soluble trace metals in atmospheric particles

    NASA Technical Reports Server (NTRS)

    Lindberg, S. E.; Harriss, R. C.

    1983-01-01

    Continental aerosols are collected above a deciduous forest in eastern Tennessee and subjected to selective extractions to determine the water-soluble and acid-leachable concentrations of Cd, Mn, Pb, and Zn. The combined contributions of these metals to the total aerosol mass is 0.5 percent, with approximately 70 percent of this attributable to Pb alone. A substantial fraction (approximately 50 percent or more) of the acid-leachable metals is soluble in distilled water. In general, this water-soluble fraction increases with decreasing particle size and with increasing frequency of atmospheric water vapor saturation during the sampling period. The pattern of relative solubilities (Zn being greater than Mn, which is approximately equal to Cd, which is greater than Pb) is found to be similar to the general order of the thermodynamic solubilities of the most probable salts of these elements in continental aerosols with mixed fossil fuel and soil sources.

  11. Total soluble solids from banana: evaluation and optimization of extraction parameters.

    PubMed

    Carvalho, Giovani B M; Silva, Daniel P; Santos, Júlio C; Izário Filho, Hélcio J; Vicente, António A; Teixeira, José A; Felipe, Maria das Graças A; Almeida e Silva, João B

    2009-05-01

    Banana, an important component in the diet of the global population, is one of the most consumed fruits in the world. This fruit is also very favorable to industry processes (e.g., fermented beverages) due to its rich content on soluble solids and minerals, with low acidity. The main objective of this work was to evaluate the influence of factors such as banana weight and extraction time during a hot aqueous extraction process on the total soluble solids content of banana. The extract is to be used by the food and beverage industries. The experiments were performed with 105 mL of water, considering the moisture of the ripe banana (65%). Total sugar concentrations were obtained in a beer analyzer and the result expressed in degrees Plato (degrees P, which is the weight of the extract or the sugar equivalent in 100 g solution at 20 degrees C), aiming at facilitating the use of these results by the beverage industries. After previous studies of characterization of the fruit and of ripening performance, a 2(2) full-factorial star design was carried out, and a model was developed to describe the behavior of the dependent variable (total soluble solids) as a function of the factors (banana weight and extraction time), indicating as optimum conditions for extraction 38.5 g of banana at 39.7 min.

  12. Total soluble solids from banana: evaluation and optimization of extraction parameters.

    PubMed

    Carvalho, Giovani B M; Silva, Daniel P; Santos, Júlio C; Izário Filho, Hélcio J; Vicente, António A; Teixeira, José A; Felipe, Maria das Graças A; Almeida e Silva, João B

    2009-05-01

    Banana, an important component in the diet of the global population, is one of the most consumed fruits in the world. This fruit is also very favorable to industry processes (e.g., fermented beverages) due to its rich content on soluble solids and minerals, with low acidity. The main objective of this work was to evaluate the influence of factors such as banana weight and extraction time during a hot aqueous extraction process on the total soluble solids content of banana. The extract is to be used by the food and beverage industries. The experiments were performed with 105 mL of water, considering the moisture of the ripe banana (65%). Total sugar concentrations were obtained in a beer analyzer and the result expressed in degrees Plato (degrees P, which is the weight of the extract or the sugar equivalent in 100 g solution at 20 degrees C), aiming at facilitating the use of these results by the beverage industries. After previous studies of characterization of the fruit and of ripening performance, a 2(2) full-factorial star design was carried out, and a model was developed to describe the behavior of the dependent variable (total soluble solids) as a function of the factors (banana weight and extraction time), indicating as optimum conditions for extraction 38.5 g of banana at 39.7 min. PMID:19082923

  13. Low acid producing solid propellants

    NASA Technical Reports Server (NTRS)

    Bennett, Robert R.

    1995-01-01

    The potential environmental effects of the exhaust products of conventional rocket propellants have been assessed by various groups. Areas of concern have included stratospheric ozone, acid rain, toxicity, air quality and global warming. Some of the studies which have been performed on this subject have concluded that while the impacts of rocket use are extremely small, there are propellant development options which have the potential to reduce those impacts even further. This paper discusses the various solid propellant options which have been proposed as being more environmentally benign than current systems by reducing HCI emissions. These options include acid neutralized, acid scavenged, and nonchlorine propellants. An assessment of the acid reducing potential and the viability of each of these options is made, based on current information. Such an assessment is needed in order to judge whether the potential improvements justify the expenditures of developing the new propellant systems.

  14. LITERATURE REVIEW OF BORIC ACID SOLUBILITY DATA

    SciTech Connect

    Crapse, K.; Kyser, E.

    2011-09-22

    A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system replaces the current dilute nitric acid strip solution with 0.01 M boric acid. This literature study is performed to determine if there is a potential for boric acid to crystallize in the lines with emphasis on the transfer lines to the Defense Waste Processing Facility. This report focuses on the aqueous phase chemistry of boric acid under conditions relevant to MCU and SWPF. Operating and transfer conditions examined for the purpose of this review include temperatures between 13 C (McLeskey, 2008) and 45 C (Fondeur, 2007) and concentrations from 0 to 3M in nitric acid as well as exposure of small amounts of entrained boric acid in the organic phase to the sodium hydroxide caustic wash stream. Experiments were also conducted to observe any chemical reactions and off-gas generation that could occur when 0.01 M boric acid solution mixes with 3 M nitric acid solution and vice versa. Based on the low concentration (0.01M) of boric acid in the MCU/SWPF strip acid and the moderate operating temperatures (13 C to 45 C), it is unlikely that crystallization of boric acid will occur in the acid strip solution under process or transfer conditions. Mixing experiments of boric and nitric acid show no measurable gas generation (< 1 cc of gas per liter of solution) under similar process conditions.

  15. Leaching behavior and solubility -- Controlling solid phases of heavy metals in municipal solid waste incinerator ash

    SciTech Connect

    Johnson, C.A.; Ziegler, F.; Kersten, M.; Moor, H.C.

    1996-12-31

    This paper highlights the uses and limitations of thermodynamic calculations in the planning of leach tests in the laboratory or for research in the field. Heavy metal solubility has been studied in leachate from Landfill Lostorf, AG, Switzerland. Also, the influence of pH on the solubility of Cu, Pb, Cd and Zn has been determined in the laboratory. The results have been compared with the maximum allowable heavy metal concentrations in equilibrium with the appropriate (hydr)oxides and carbonates. Copper is supersaturated with respect to Cu(OH){sub 2} in both laboratory and field studies. Complexation with organic ligands is a probable explanation for this observation. Both Zn and Pb are undersaturated with respect to pure (hydr)oxides and carbonates, though agreement between calculations and measurements are close enough, that PbCO{sub 3} could be controlling the solubility in the laboratory experiments. The markedly lower concentrations of Pb in the field in comparison with the laboratory data could be explained by the affinity for Pb to bind to solids and the higher solid:solution ratio in field conditions. The solubility of Cd could be controlled by the formation of CdCO{sub 3}. The relatively high concentrations of Mo in the landfill leachate could be limited by the precipitation of CaMoO{sub 4}.

  16. Solubility of HCL in sulfuric acid at stratospheric temperatures

    NASA Technical Reports Server (NTRS)

    Williams, Leah R.; Golden, David M.

    1993-01-01

    The solubility of HCl in sulfuric acid was measured using a Knudsen cell technique. Effective Henry's law constants are reported for sulfuric acid concentrations between 50 and 60 weight percent and for temperatures between 220 and 230 K. The measured values indicate that very little HCl will be dissolved in the stratospheric sulfate aerosol particles.

  17. Solubility and Reaction Rates of Aluminum Solid Phases Under Hydrothermal Conditions

    SciTech Connect

    Benezeth, P.; Palmer, D.A.; Wesolowski, D.

    1999-11-14

    Experimental studies involving equilibrium solubility and dissolution/precipitation rates were initiated on boehmite (AIOOH) using a hydrogen-electrode concentration cell (HECC). This cell provides continuous, accurate in situ pH measurements of solid/solution mixtures to 295 C with provision for either removing solution samples for analysis of the metal content, or adding either of two titrants. This cell has been recently used to measure the solubility of minerals such as brucite; boehmite, zincite, arid magnetite. The ability to perturb pH, isothermally by addition of acidic or basic titrant opens the door for studies of the kinetics of dissolution/precipitation, even for relatively fast reactions. By monitoring the change in pH, with time, detailed kinetic information can be obtained without the need for sampling.

  18. The removal of kaolinite suspensions by acid-soluble and water-soluble chitosans.

    PubMed

    Chung, Ying-Chien; Wu, Li-Chun; Chen, Chih-Yu

    2013-01-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This research compared the coagulant performance of acid-soluble chitosan with water-soluble chitosan and with coagulant mixtures of chitosan and aluminium sulfate (alum). We also assessed the coagulant performance of chitosan and poly-aluminium chloride (PAC) to remove kaolinite from turbid water. In addition, we evaluated their respective coagulation efficiencies under different coagulant concentrations, degrees of turbidity (NTU) and pH levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants in order to illustrate major factors affecting kaolinite coagulation. The optimal concentrations of acid- versus water- soluble chitosan required to remove kaolinite from a 300 NTU suspension were 4.0 and 10.0 mg/l, respectively-with individual efficiencies of 79.3 and 92.4%, in that order. Optimum concentrations ofwater-soluble chitosan demonstrated a broader range than that of acid-soluble chitosan. In addition, it is of note that chitosan/alum and chitosan/PAC water-soluble coagulant mixtures demonstrated much wider ranges of optimal concentrations for turbidity reduction than either alum or PAC alone. Moreover, our water-soluble chitosan coagulant mixtures produced denser floc with elevated settling velocities that favour cost savings relevant to both installation and operational expenses. Based on our observations of these noteworthy performances, we confidently propose that a coagulant mixture with a 1:1 mass ratio of chitosan and alum presents a remarkably more cost-effective alternative to the use of chitosan alone in water treatment systems. PMID:23530342

  19. The expanded Hansen approach to solubility parameters. Paracetamol and citric acid in individual solvents.

    PubMed

    Barra, J; Lescure, F; Doelker, E; Bustamante, P

    1997-07-01

    In this study two solubility-parameter models have been compared using as dependent variables the logarithm of the mole fraction solubility, lnX2e, and ln(alpha)/U (originally used in the extended Hansen method), where alpha is the activity coefficient and U is a function of the molar volume of the solute and the volume fraction of the solvent. The results show for the first time the proton-donor and -acceptor hydrogen-bonding capacities of paracetamol, as measured by the acidic and basic partial-solubility parameters. The influence of solvents on the differential scanning calorimetry (DSC) pattern of the solid phases was also studied in relation to the solubility models tested. Citric acid was chosen as a test substance because of its high acidity and its proton donor capacity to form hydrogen bonds with basic solvents. The partial acidic and basic solubility parameters obtained from multiple regression were consistent with this property, validating the model chosen. The results show that the more direct lnX2e variable was more suitable for fitting both models, and the four-parameter model seemed better for describing the interactions between solvent and solute. PMID:9255705

  20. Formation of water-soluble metal cyanide complexes from solid minerals by Pseudomonas plecoglossicida.

    PubMed

    Faramarzi, Mohammad A; Brandl, Helmut

    2006-06-01

    A few Pseudomonas species are able to form hydrocyanic acid (HCN), particularly when grown under glycine-rich conditions. In the presence of metals, cyanide can form water-soluble metal complexes of high chemical stability. We studied the possibility to mobilize metals as cyanide complexes from solid minerals using HCN-forming microorganisms. Pseudomonas plecoglossicida was cultivated in the presence of copper- and nickel-containing solid minerals. On powdered elemental nickel, fast HCN generation within the first 12 h of incubation was observed and water-soluble tetracyanaonickelate was formed. Cuprite, tenorite, chrysocolla, malachite, bornite, turquoise, millerite, pentlandite as well as shredded electronic scrap was also subjected to a biological treatment. Maximum concentrations of cyanide-complexed copper corresponded to a solubilization of 42% and 27% when P. plecoglossicida was grown in the presence of cuprite or tenorite, respectively. Crystal system, metal oxidation state and mineral hydrophobicity might have a significant influence on metal mobilization. However, it was not possible to allocate metal mobilization to a single mineral property. Cyanide-complexed gold was detected during growth on manually cut circuit boards. Maximum dicyanoaurate concentration corresponded to a 68.5% dissolution of the total gold added. These findings represent a novel type of microbial mobilization of nickel and copper from solid minerals based on the ability of certain microbes to form HCN.

  1. Formation of water-soluble metal cyanide complexes from solid minerals by Pseudomonas plecoglossicida.

    PubMed

    Faramarzi, Mohammad A; Brandl, Helmut

    2006-06-01

    A few Pseudomonas species are able to form hydrocyanic acid (HCN), particularly when grown under glycine-rich conditions. In the presence of metals, cyanide can form water-soluble metal complexes of high chemical stability. We studied the possibility to mobilize metals as cyanide complexes from solid minerals using HCN-forming microorganisms. Pseudomonas plecoglossicida was cultivated in the presence of copper- and nickel-containing solid minerals. On powdered elemental nickel, fast HCN generation within the first 12 h of incubation was observed and water-soluble tetracyanaonickelate was formed. Cuprite, tenorite, chrysocolla, malachite, bornite, turquoise, millerite, pentlandite as well as shredded electronic scrap was also subjected to a biological treatment. Maximum concentrations of cyanide-complexed copper corresponded to a solubilization of 42% and 27% when P. plecoglossicida was grown in the presence of cuprite or tenorite, respectively. Crystal system, metal oxidation state and mineral hydrophobicity might have a significant influence on metal mobilization. However, it was not possible to allocate metal mobilization to a single mineral property. Cyanide-complexed gold was detected during growth on manually cut circuit boards. Maximum dicyanoaurate concentration corresponded to a 68.5% dissolution of the total gold added. These findings represent a novel type of microbial mobilization of nickel and copper from solid minerals based on the ability of certain microbes to form HCN. PMID:16684101

  2. Water-enhanced solubility of carboxylic acids in organic solvents and its application to extraction processes

    SciTech Connect

    Starr, J.N. ); King, C.J. )

    1992-11-01

    This paper reports on solubilities of carboxylic acids in certain organic solvents which increase sharply as the concentration of water in the solvent increases. This phenomenon leads to a method of regeneration for solvent-extraction processes whereby coextracted water is selectively removed from the extract, such as by stripping, thereby precipitating the acid. The removal of a minor constituent to cause precipitation reduces energy consumption, in contrast with bulk removal of solvent. Solubilities of fumaric acid were measured in a number of organic solvents, with varying amounts of water in the organic phase. Cyclohexanone and methylcyclohexanone were chosen as solvents for which detailed solid-liquid and liquid-liquid equilibria were measured for adipic, fumaric, and succinic acids in the presence of varying concentrations of water, at both 25 and 45[degrees]C. Batch precipitation experiments were performed to demonstrate the processing concept and determine the relative volatility of water to solvent in the presence of carbon.

  3. Experimental evaluation of solid solubility of lanthanide and transuranium nitrides into ZrN matrix

    NASA Astrophysics Data System (ADS)

    Takano, Masahide

    2013-09-01

    The solid solution formation between ZrN and some selected lanthanide/transuranium (TRU) nitrides was examined by powder metallurgy of the nitride mixtures and simultaneous carbothermic nitridation of the oxide mixtures. The solid solubility into ZrN was determined by powder X-ray diffraction measurements as a function of relative lattice parameter difference (RLPD). The upper limit of RLPD value for the complete solid solubility was evaluated to be 8.6-8.9% in the temperature range of 1773-1973 K from the results of powder metallurgy. The solid solubility into ZrN decreases sharply in the greater RLPD value range. The solid solubility into ZrN in the products of carbothermic nitridation was lower, according to the influence of dissolved carbon impurity. The TRU composition limits for (Zr,TRU)N single-phase solid solution formation were simulated for the basis of fuel design works.

  4. Solubility of solid solutes in HFA-134a with a correlation to physico-chemical properties.

    PubMed

    Hoye, Julie A; Gupta, Abhishek; Myrdal, Paul B

    2008-01-01

    The reformulation of pressurized metered dose inhalers with HFAs from CFCs has given rise to many solubility challenges. Compounds and excipients previously used in CFCs were observed to have significantly different solubility values in HFA-134a. In this investigation, the solubility values of 36 solid organic solutes in HFA-134a were determined. The set of compounds display diverse physico-chemical properties and yielded solubility values that ranged over 4 orders of magnitude. The experimental solubilities were compared to calculated values obtained from ideal solubility theory as well as from regular solution theory. While the theoretical models did not offer absolute solubility estimations, a clear correlation with the ideal solubility (melting point) was noted. Further consideration utilizing multiple linear regression models afforded correlations based on molecular properties. Regression models, containing melting point and log P (or molar volume) resulted in promising correlations having average absolute errors of 0.43 log units, or a factor of 2.69.

  5. The relationship between dissolved humic acids and soluble iron in estuaries

    NASA Technical Reports Server (NTRS)

    Fox, L. E.

    1984-01-01

    Dissolved humic acid and soluble iron appear to be chemically unassociated in estuaries despite their coincident removal. This conclusion is supported by differences in the aggregation kinetics of soluble iron and dissolved humic acid, the inability of extracted humic acid to stabilize laboratory preparations of ferric hydroxide, and decreasing ratios of humic acid carbon to soluble iron along the axes of some estuaries.

  6. Precipitation diagrams and solubility of uric acid dihydrate

    NASA Astrophysics Data System (ADS)

    Babić-Ivančić, V.; Füredi-Milhofer, H.; Brown, W. E.; Gregory, T. M.

    1987-07-01

    The solubility of uric acid dihydrate (UA·2H 2O) and the precipitation of UA·2H 2O and anhydrous uric acid (UA) from solutions containing sodium hydroxide and hydrochloric acid have been investigated. For the solubility studies, crystals of pure UA·2H 2O were prepared and equilibrated with water and with solutions of HCl or NaOH for 60 min or 20 h, respectively. The equilibrium pH (pH = 2-6.25) and uric acid concentration were determined. For the precipitation experiments, commercial UA was dissolved in NaOH in a 1:1.1 molar ratio and UA·2H 2O and/or UA were precipitated with hydrochloric acid. The precipitates and/or supernatants were examined 24 h after sample preparation. The results are represented in the form of tables, precipitation diagrams and "chemical potential" diagrams. Solubility measurements with 60 min equilibration times yielded the solubility products of UA·2H 2O, K sp(298 K) = (0.926 ± 0.025) × 10 -9mol2dm-6 and K sp(310 K) = (2.25 ± 0.05) × 10 -9mol2dm-6 and the first dissociation constants of uric acid, K 1(298 K) = (2.45 ± 0.07) × 10 -6moldm-3 and K 1(310 K) = (3.63 ± 0.08) × 10 -6moldm-3. Precipitation diagrams show that under the given experimental conditions, at 298 K, UA·2H 2O is stable for 24 h while at 310 K this was true only for precipitates formed from solutions of high supersaturations. At lower supersaturations, mixtures of UA·2H 2O and UA formed. Consequently, while the Ksp value determined from precipitation data obtained at 298 K (K sp = 1.04 × 10 -9mol2dm-6) was consistent with the respective solubility product, the 310 K precipitation boundary yielded an ion activity product, AP, the value of which fulfills the conditions Ksp(UA) < AP < Ksp (UA·2H 2O). Similar ion activity products were obtained from solubility measurements in pure water at 20 h equilibration time.

  7. C-104 high-level waste solids: Washing/leaching and solubility versus temperature studies

    SciTech Connect

    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.

  8. Solubility and dissolution enhancement of etoricoxib by solid dispersion technique using sugar carriers.

    PubMed

    Das, Abhisekh; Nayak, Amit Kumar; Mohanty, Biswaranjan; Panda, Satyabrata

    2011-01-01

    The aim of the present study was to improve solubility and dissolution of the poorly aqueous soluble drug, etoricoxib by solvent evaporation technique using various sugar carriers, such as lactose, sucrose, and mannitol. Etoricoxib solid dispersions and their respective physical mixtures using lactose, sucrose, and mannitol were prepared in different ratios by solvent evaporation technique. The percent yield, drug content, saturation solubility, and in vitro dissolution of etoricoxib solid dispersions and physical mixtures were analyzed. Etoricoxib solid dispersions were characterized by FTIR spectroscopy, XRD, and DSC analysis. The FTIR spectroscopic analysis revealed the possibility of intermolecular hydrogen bonding in various solid dispersions. The XRD and DSC studies indicated the transformation of crystalline etoricoxib (in pure drug) to amorphous etoricoxib (in solid dispersions) by the solid dispersion technology. Both the aqueous solubility and dissolution of etoricoxib were observed in all etoricoxib solid dispersions as compared with pure etoricoxib and their physical mixtures. The in vitro dissolution studies exhibited improved dissolution in case of solid dispersion using lactose than the solid dispersions using both sucrose and mannitol. The in vitro dissolution of etoricoxib from these solid dispersions followed Hixson-Crowell model. PMID:22389861

  9. Solubility Database

    National Institute of Standards and Technology Data Gateway

    SRD 106 IUPAC-NIST Solubility Database (Web, free access)   These solubilities are compiled from 18 volumes (Click here for List) of the International Union for Pure and Applied Chemistry(IUPAC)-NIST Solubility Data Series. The database includes liquid-liquid, solid-liquid, and gas-liquid systems. Typical solvents and solutes include water, seawater, heavy water, inorganic compounds, and a variety of organic compounds such as hydrocarbons, halogenated hydrocarbons, alcohols, acids, esters and nitrogen compounds. There are over 67,500 solubility measurements and over 1800 references.

  10. Predicting the solid solubility limit in high-entropy alloys using the molecular orbital approach

    NASA Astrophysics Data System (ADS)

    Sheikh, Saad; Klement, Uta; Guo, Sheng

    2015-11-01

    High-entropy alloys (HEAs) are currently at the research frontier of metallic materials. Understanding the solid solubility limit in HEAs, such a highly concentrated multicomponent alloy system, is scientifically intriguing. It is also technically important to achieve desirable mechanical properties by controlling the formation of topologically or geometrically closed packed phases. Previous approaches to describe the solid solubilities in HEAs could not accurately locate the solubility limit and have to utilize at least two parameters. Here, we propose to use a single parameter, the average energy of d-orbital levels, Md, to predict the solid solubility limit in HEAs. It is found that Md can satisfactorily describe the solid solubilities in fcc structured HEAs containing 3 d transition metals, and also in bcc structured HEAs. This finding will greatly simplify the alloys design and lends more flexibility to control the mechanical properties of HEAs. When 4 d transition metals are alloyed, Md alone cannot describe the solid solubility limit in fcc structured HEAs, due to the large increase of the bond strength that can be gauged by the bond order, Bo. The potential opportunities and challenges with applying the molecular orbital approach to HEAs are discussed.

  11. Solubility relationships of aluminium and iron minerals associated with acid mine drainage

    SciTech Connect

    Sullivan, P.J.; Yelton, J.L. ); Reddy, K.J. )

    1988-06-01

    The ability to properly manage the oxidation of pyritic minerals and associated acid mine drainage is dependent upon understanding the chemistry of the disposal environment. One accepted disposal method is placing pyritic-containing materials in the groundwater environment. The objective of this study was to examine solubility relationships of Al and Fe minerals associated with pyritic waste disposed in a low leaching aerobic saturated environment. Two eastern oil shales were used in this oxidizing equilibration study, a New Albany Shale (unweathered, 4.6 percent pyrite), and a Chattanooga Shale (weathered, 1.5 percent pyrite). Oil shale samples were equilibrated with distilled-deionized water from 1 to 180 d with a 1:1 solid-to-solution ratio. The suspensions were filtered and the clear filtrates were analyzed for total cations and anions. Ion activities were calculated from total concentrations. Below pH 6.0, depending upon SO{sub 4}{sup 2{minus}} activity, Al{sup 3+} solubility was controlled by AlOHSO{sub 4} (solid phase) for both shales. The results of this study indicate that below pH 6.0, Al{sup 3+} and Fe{sup 3+} solubilities, are limited by basic Al and Fe sulfate solid phases (AlOHSO{sub 4(s)} and FeHSO{sub 4(s)}). The results from this study further indicate that the acidity in oil shale waters is produced from the hydrolysis of Al{sup 3+} and Fe{sup 3+} activities in solution. These results indicate a fundamental change in the stoichiometric equations used to predict acidity from iron sulfide oxidation. The results of this study also indicate that water quality predictions associated with acid mine drainage can be based on fundamental thermodynamic relationships. As a result, waste management decisions can be based on waste-specific/site test methods.

  12. Proton conducting membrane using a solid acid

    NASA Technical Reports Server (NTRS)

    Chisholm, Calum (Inventor); Narayanan, Sekharipuram R. (Inventor); Boysen, Dane (Inventor); Haile, Sossina M. (Inventor)

    2002-01-01

    A solid acid material is used as a proton conducting membrane in an electrochemical device. The solid acid material can be one of a plurality of different kinds of materials. A binder can be added, and that binder can be either a nonconducting or a conducting binder. Nonconducting binders can be, for example, a polymer or a glass. A conducting binder enables the device to be both proton conducting and electron conducting. The solid acid material has the general form M.sub.a H.sub.b (XO.sub.t).sub.c.

  13. Physical stability of solid dispersions with respect to thermodynamic solubility of tadalafil in PVP-VA.

    PubMed

    Wlodarski, K; Sawicki, W; Kozyra, A; Tajber, L

    2015-10-01

    The aim of this paper was to evaluate physical stability of solid dispersions in respect to the drug, tadalafil (Td), in vinylpyrrolidone and vinyl acetate block copolymer (PVP-VA). Nine solid dispersions of Td in PVP-VA (Td/PVP-VA) varied in terms of quantitative composition (1:9-9:1, w/w) were successfully produced by spray-drying. Their amorphous nature, supersaturated character and molecular level of mixing (a solid solution structure) were subsequently confirmed using DSC, PXRD, SEM and calculation of Hansen total solubility parameters. Due to thermal degradation of both components before the melting point of Td (302.3°C), an approach based on the drug crystallization from the supersaturated solid dispersion was selected to calculate the solubility of Td in the polymer. Annealing of the Td/PVP-VA solid dispersion (1:1, w/w) at selected temperatures above its Tg resulted in different stable solid dispersions. According to the Gordon-Taylor equation their new Tgs gave the information about the quantitative composition which corresponded to the thermodynamic solubility of Td in PVP-VA at given temperatures of annealing. The obtained relationship was fitted to the exponential function, with the calculated solubility of Td of 20.5% at 25°C. This value was in accordance with the results of hot stage polarizing light microscopy as well as stability tests carried out at 80°C and 0% RH, in which Td solid dispersions containing 10-20% of the drug were the only systems that did not crystallize within two months. A thermal analysis protocol utilizing a fast heating rate was shown to generate Td solubility data complementing the solid dispersion method. The Flory-Huggins model applied for the Td/PVP-VA system yielded the solubility value of 0.1% at 25°C, showing the lack of applicability in this case.

  14. Solid Solubilities of Pu, U, Gd and Hf in Candidate Ceramic Nuclear Wasteforms

    SciTech Connect

    Vance, Eric R.; Carter, M. L.; Lumpkin, G. R.; Day, R. A.; Begg, B. D.

    2001-04-02

    This goal of this research project was to determine the solid solubility of Pu, U, Gd, and Hf in candidate ceramics for immobilization of high-level nuclear waste. The experimental approach was to saturate each phase by adding more than the solid solubility limit of the given cation, using a nominated substitution scheme, and then analyzing the candidate phase that formed to evaluate the solid solubility limit under firing conditions. Confirmation that the solid solution limit had been reached insofar as other phases rich in the cation of interest was also required. The candidate phases were monazite, titanite, zirconolite, perovskite, apatite, pyrochlore, and brannerite. The valences of Pu and U were typically deduced from the firing atmosphere, and charge balancing in the candidate phase composition as evaluated from electron microscopy, although in some cases it was measured directly by x-ray absorption and diffuse reflectance spectroscopies (for U). Tetravalent Pu and U have restricted (< 0.1 formula units) solid solubility in apatite, titanite, and perovskite. Trivalent Pu has a larger solubility in apatite and perovskite than Pu4+. U3+ appears to be a credible species in reduced perovskite with a solubility of {approximately} 0.25 f.u. as opposed to {approximately} 0.05 f.u. for U4+. Pu4+ is a viable species in monazite and is promoted at lower firing temperatures ({approximately} 800 C) in an air atmosphere. Hf solubility is restricted in apatite, monazite (< 0.1 f.u.), but is {approximately} 0.2 and 0.5 f.u. in brannerite and titanite, respectively. Gd solubility is extended in all phases except for titanite ({approximately} 0.3 f.u.). U5+ was identified by DRS observations of absorption bands in the visible/near infrared photon energy ranges in brannerite and zirconolite, and U4+ in zirconolite was similarly identified.

  15. Proton conducting membrane using a solid acid

    NASA Technical Reports Server (NTRS)

    Haile, Sossina M. (Inventor); Chisholm, Calum (Inventor); Boysen, Dane A. (Inventor); Narayanan, Sekharipuram R. (Inventor)

    2006-01-01

    A solid acid material is used as a proton conducting membrane in an electrochemical device. The solid acid material can be one of a plurality of different kinds of materials. A binder can be added, and that binder can be either a nonconducting or a conducting binder. Nonconducting binders can be, for example, a polymer or a glass. A conducting binder enables the device to be both proton conducting and electron conducting.

  16. A physiological and genetic approach to the improvement of tomato (Lycopersicon esculentum Mill. ) fruit soluble solids

    SciTech Connect

    Damon, S.E.

    1989-01-01

    Physiological processes and the genetic basis determining soluble solids content (SSC) of processing tomato fruit were addressed. Analysis of ({sup 3}H)-(fructosyl)-sucrose translocation in tomato indicates that phloem unloading in the fruit occurs, at least in part, to the apoplast. Apoplastic sucrose, glucose and fructose concentrations were estimated as 1 to 7, 12 to 49 and 8 to 63 millimolar, respectively in tomato fruit pericarp. Short-term uptake of ({sup 14}C)sucrose, -glucose and -fructose in tomato pericarp discs showes first order kinetics over the physiologically relevant concentration range. The uptake of ({sup 14}C)-(glycosyl)-1{prime}fluorosucrose was identical to the rate of ({sup 14}C) sucrose uptake suggesting sucrose may be taken up directly without prior extracellular hydrolysis. Short-term uptake of all three sugars was insensitive to 10 micromolar carbonyl cyanide m-chlorophenylhydrazone and to 10 micromolar p-chloromercuribenzene sulfonic acid. However, long-term accumulation of glucose was sensitive to carbonyl cyanide m-chlorophenylhydrazone. Sugar uptake across the plasmamembrane does not appear to be energy dependent, suggesting that sugar accumulation in the tomato is driven by subsequent intracellular metabolism and/or active uptake at the tonoplast. Fourteen genomic DNA probes and ten restriction endonucleases were used to identify restriction fragment length polymorphisms (RFLPs) useful in the linkage analysis of quantitative trait loci controlling the expression of SSC in a segregating F{sub 2} population from a cross between L. esculentum (UC204B) and L. cheesmanii f. minor, a wild species with high fruit soluble solids. RFLPs were detected between the DNAs of the two tomato species with all 14 probes.

  17. Design of biodegradable nanoparticles: a novel approach to encapsulating poorly soluble phytochemical ellagic acid

    NASA Astrophysics Data System (ADS)

    Bala, I.; Bhardwaj, V.; Hariharan, S.; Sitterberg, J.; Bakowsky, U.; Kumar, M. N. V. Ravi

    2005-12-01

    Nanosizing of poorly water soluble drugs or incorporating them into nanoparticles to increase their solubility and thereby the bioavailability has become a favoured approach today. This work describes a novel method for encapsulating poorly water soluble phytochemical ellagic acid that is also sparingly soluble/insoluble in routine solvents used to prepare nanoparticles.

  18. Superprotonic solid acids: Structure, properties, and applications

    NASA Astrophysics Data System (ADS)

    Boysen, Dane Andrew

    In this work, the structure and properties of superprotonic MH nXO4-type solid acids (where M = monovalent cation, X = S, Se, P, As, and n = 1, 2) have been investigated and, for the first time, applied in fuel cell devices. Several MH nXO4-type solid acids are known to undergo a "superprotonic" solid-state phase transition upon heating, in which the proton conductivity increases by several orders of magnitude and takes on values of ˜10 -2O-1cm-1. The presence of superprotonic conductivity in fully hydrogen bonded solid acids, such as CsH2PO4, has long been disputed. In these investigations, through the use of pressure, the unequivocal identification of superprotonic behavior in both RbH2PO4 and CsH2PO 4 has been demonstrated, whereas for chemically analogous compounds with smaller cations, such as KH2PO4 and NaH2PO 4, superprotonic conductivity was notably absent. Such observations have led to the adoption of radius ratio rules, in an attempt to identify a critical ion size effect on the presence of superprotonic conductivity in solid acids. It has been found that, while ionic size does play a prominent role in the presence of superprotonic behavior in solid acids, equally important are the effects of ionic and hydrogen bonding. Next, the properties of superprotonic phase transition have been investigated from a thermodynamic standpoint. With contributions from this work, a formulation has been developed that accounts for the entropy resulting from both the disordering of both hydrogen bonds and oxy-anion librations in the superprotonic phase of solid acids. This formulation, fundamentally derived from Linus Pauling's entropy rules for ice, accurately accounts for the change in entropy through a superprotonic phase transition. Lastly, the first proof-of-priniciple fuel cells based upon solid acid electrolytes have been demonstrated. Initial results based upon a sulfate electrolyte, CsHSO4, demonstrated the viability of solid acids, but poor chemical stability

  19. Comparison of a miniaturized shake-flask solubility method with automated potentiometric acid/base titrations and calculated solubilities.

    PubMed

    Glomme, A; März, J; Dressman, J B

    2005-01-01

    Solubility is one of the most important parameters for lead selection and optimization during drug discovery. Its determination should therefore take place as early as possible in the process. Because of the large numbers of compounds involved and the very low amounts of each compound available in the early development stage, it is highly desirable to measure the solubility with as little compound as possible and to be able to improve the throughput of the methods used. In this work, a miniaturized shake-flask method was developed and the solubility results were compared with those measured by semiautomated potentiometric acid/base titrations and computational methods for 21 poorly soluble compounds with solubilities mostly in the range 0.03-30 microg/mL. The potentiometric method is very economical (approximately 100 microg of a poorly soluble compound is needed) and is able to create a pH/solubility profile with one single determination, but is limited to ionizable compounds. The miniaturized shake-flask method can be used for all compounds and a wide variety of media. Its precision and throughput proved superior to the potentiometric method for very poorly soluble compounds. Up to 20 compounds a week can be studied with one set-up. Calculated solubility data seem to be sufficient for a first estimate of the solubility, but they cannot currently be used as a substitute for experimental measurements at key decision points in the development process.

  20. Wet spinning of solid polyamic acid fibers

    NASA Technical Reports Server (NTRS)

    Dorogy, William E., Jr. (Inventor); St.clair, Anne K. (Inventor)

    1991-01-01

    The invention is a process for the production of solid aromatic polyamic acid and polyimide fibers from a wet gel or coagulation bath wet gel using N,N-dimethylacetamide (DMAc) solutions of the polyamic acid derived from aromatic dianhydrides such as 3,3',4,4' benzophenonetetra carboxylic dianhydride (BTDA) and aromatic diamines such as 4,4'-oxydianiline (4,4'-ODA). By utilizing the relationship among coagulation medium and concentration, resin inherent viscosity, resin percent solids, filament diameter, and fiber void content, it is possible to make improved polyamic acid fibers. Solid polyimide fibers, obtained by the thermal cyclization of the polyamic acid precursor, have increased tensile properties compared to fibers containing macropores from the same resin system.

  1. Enhancement of solubility and dissolution of cilostazol by solid dispersion technique.

    PubMed

    Park, Jun-Hyung; Choi, Hoo-Kyun

    2015-07-01

    Cilostazol is practically insoluble in water and thus results in poor bioavailability. Only a few approaches have been reported for improving the bioavailability of cilostazol. Solid dispersion technique via solvent evaporation method was applied to improve the solubility and dissolution of cilostazol. Various polymers, mixture of polymer and surfactant, and mixture of polymers were screened as a carrier for the solid dispersion. Solubility of cilostazol was improved significantly when Eudragit(®) L100 was used as a carrier. However, addition of surfactant to Eudragit(®) L100 decreased the solubility slightly. Whereas, the mixture of Eudragit(®) L100 and Eudragit(®) S100 as a carrier system further increased the solubility. Based on the highest solubility obtained among the carriers screened, 1:1 ratio of Eudragit(®) L100 and Eudragit(®) S100 was selected as a carrier, and drug to carrier ratio was optimized to 1:5. Differential scanning calorimetry and X-ray diffraction studies showed that the characteristic peak of cilostazol disappeared in the solid dispersion, indicating that cilostazol existed in amorphous form in this formulation. Spray drying method was superior to vacuum drying method in terms of dissolution rate. Meanwhile, it was observed that the disintegration rate and the concentration of polymer had some effect on the crystallization of cilostazol in dissolution medium. Tablet formulation containing spray dried solid dispersion showed significant improvement in dissolution as compared to the commercial tablet.

  2. Comparative study on solid self-nanoemulsifying drug delivery and solid dispersion system for enhanced solubility and bioavailability of ezetimibe

    PubMed Central

    Rashid, Rehmana; Kim, Dong Wuk; Yousaf, Abid Mehmood; Mustapha, Omer; Din, Fakhar ud; Park, Jong Hyuck; Yong, Chul Soon; Oh, Yu-Kyoung; Youn, Yu Seok; Kim, Jong Oh; Choi, Han-Gon

    2015-01-01

    Background The objective of this study was to compare the physicochemical characteristics, solubility, dissolution, and oral bioavailability of an ezetimibe-loaded solid self-nanoemulsifying drug delivery system (SNEDDS), surface modified solid dispersion (SMSD), and solvent evaporated solid dispersion (SESD) to identify the best drug delivery system with the highest oral bioavailability. Methods For the liquid SNEDDS formulation, Capryol 90, Cremophor EL, and Tween 80 were selected as the oil, surfactant, and cosurfactant, respectively. The nanoemulsion-forming region was sketched using a pseudoternary phase diagram on the basis of reduced emulsion size. The optimized liquid SNEDDS was converted to solid SNEDDS by spray drying with silicon dioxide. Furthermore, SMSDs were prepared using the spray drying technique with various amounts of hydroxypropylcellulose and Tween 80, optimized on the basis of their drug solubility. The SESD formulation was prepared with the same composition of optimized SMSD. The aqueous solubility, dissolution, physicochemical properties, and pharmacokinetics of all of the formulations were investigated and compared with the drug powder. Results The drug existed in the crystalline form in SMSD, but was changed into an amorphous form in SNEDDS and SESD, giving particle sizes of approximately 24, 6, and 11 µm, respectively. All of these formulations significantly improved the aqueous solubility and dissolution in the order of solid SNEDDS ≥ SESD > SMSD, and showed a total higher plasma concentration than did the drug powder. Moreover, SESD gave a higher area under the drug concentration time curve from zero to infinity than did SNEDDS and SMSD, even if they were not significantly different, suggesting more improved oral bioavailability. Conclusion Among the various formulations tested in this study, the SESD system would be strongly recommended as a drug delivery system for the oral administration of ezetimibe with poor water solubility

  3. Benzoic acid 2-hydroxylase, a soluble oxygenase from tobacco, catalyzes salicylic acid biosynthesis

    SciTech Connect

    Leon, J.; Shulaev, V.; Yalpani, N.

    1995-10-24

    Benzoic acid 2-hydroxylase (BA2H) catalyzes the biosynthesis of salicylic acid from benzoic acid. The enzyme has been partially purified and characterized as a soluble protein of 160 kDa. High-efficiency in vivo labeling of salicyclic acid with {sup 18}O{sub 2} suggested that BA2H is an oxygenase that specifically hydroxylates the ortho position of benzoic acid. The enzyme was strongly induced by either tobacco mosaic virus inoculation of benzoic acid infiltration of tobacco leaves and it was inhibited by CO and other inhibitors of cytochrome P450 hydroxylases. The BA2H activity was immunodepleted by antibodies raised against SU2, a soluble cytochrome P450 from Streptomyces griseolus. The anti-SU2 antibodies immunoprecipitated a radiolabeled polypeptide of around 160 kDa from the soluble protein extracts of L-[{sup 35}S]-methionine-fed tobacco leaves. Purified BA2H showed CO-difference spectra with a maximum at 457 nm. These data suggest that BA2H belongs to a novel class of soluble, high molecular weight cytochrome P450 enzymes. 21 refs., 6 figs., 1 tab.

  4. Soluble phosphate fertilizer production using acid effluent from metallurgical industry.

    PubMed

    Mattiello, Edson M; Resende Filho, Itamar D P; Barreto, Matheus S; Soares, Aline R; Silva, Ivo R da; Vergütz, Leonardus; Melo, Leônidas C A; Soares, Emanuelle M B

    2016-01-15

    Preventive and effective waste management requires cleaner production strategies and technologies for recycling and reuse. Metallurgical industries produce a great amount of acid effluent that must be discarded in a responsible manner, protecting the environment. The focus of this study was to examine the use of this effluent to increase reactivity of some phosphate rocks, thus enabling soluble phosphate fertilizer production. The effluent was diluted in deionized water with the following concentrations 0; 12.5; 25; 50; 75% (v v(-1)), which were added to four natural phosphate rocks: Araxá, Patos, Bayovar and Catalão and then left to react for 1 h and 24 h. There was an increase in water (PW), neutral ammonium citrate (PNAC) and citric acid (PCA) soluble phosphorus fractions. Such increases were dependent of rock type while the reaction time had no significant effect (p < 0.05) on the chemical and mineralogical phosphate characteristics. Phosphate fertilizers with low toxic metal concentrations and a high level of micronutrients were produced compared to the original natural rocks. The minimum amount of total P2O5, PNAC and PW, required for national legislation for phosphate partially acidulated fertilizer, were met when using Catalão and the effluent at the concentration of 55% (v v(-1)). Fertilizer similar to partially acidulated phosphate was obtained when Bayovar with effluent at 37.5% (v v(-1)) was used. Even though fertilizers obtained from Araxá and Patos did not contain the minimum levels of total P2O5 required by legislation, they can be used as a nutrient source and for acid effluent recycling and reuse. PMID:26496844

  5. Soluble phosphate fertilizer production using acid effluent from metallurgical industry.

    PubMed

    Mattiello, Edson M; Resende Filho, Itamar D P; Barreto, Matheus S; Soares, Aline R; Silva, Ivo R da; Vergütz, Leonardus; Melo, Leônidas C A; Soares, Emanuelle M B

    2016-01-15

    Preventive and effective waste management requires cleaner production strategies and technologies for recycling and reuse. Metallurgical industries produce a great amount of acid effluent that must be discarded in a responsible manner, protecting the environment. The focus of this study was to examine the use of this effluent to increase reactivity of some phosphate rocks, thus enabling soluble phosphate fertilizer production. The effluent was diluted in deionized water with the following concentrations 0; 12.5; 25; 50; 75% (v v(-1)), which were added to four natural phosphate rocks: Araxá, Patos, Bayovar and Catalão and then left to react for 1 h and 24 h. There was an increase in water (PW), neutral ammonium citrate (PNAC) and citric acid (PCA) soluble phosphorus fractions. Such increases were dependent of rock type while the reaction time had no significant effect (p < 0.05) on the chemical and mineralogical phosphate characteristics. Phosphate fertilizers with low toxic metal concentrations and a high level of micronutrients were produced compared to the original natural rocks. The minimum amount of total P2O5, PNAC and PW, required for national legislation for phosphate partially acidulated fertilizer, were met when using Catalão and the effluent at the concentration of 55% (v v(-1)). Fertilizer similar to partially acidulated phosphate was obtained when Bayovar with effluent at 37.5% (v v(-1)) was used. Even though fertilizers obtained from Araxá and Patos did not contain the minimum levels of total P2O5 required by legislation, they can be used as a nutrient source and for acid effluent recycling and reuse.

  6. Water-enhanced solubility of carboxylic acids in organic solvents and its applications to extraction processes

    SciTech Connect

    Starr, J.N.; King, C.J.

    1991-11-01

    The solubilities of carboxylic acids in certain organic solvents increase remarkably with an increasing amount of water in the organic phase. This phenomenon leads to a novel extract regeneration process in which the co-extracted water is selectively removed from an extract, and the carboxylic acid precipitates. This approach is potentially advantageous compared to other regeneration processes because it removes a minor component of the extract in order to achieve a large recovery of acid from the extract. Carboxylic acids of interest include adipic acid, fumaric acid, and succinic acid because of their low to moderate solubilities in organic solvents. Solvents were screened for an increase in acid solubility with increased water concentration in the organic phase. Most Lewis-base solvents were found to exhibit this increased solubility phenomena. Solvents that have a carbonyl functional group showed a very large increase in acid solubility. 71 refs., 52 figs., 38 tabs.

  7. Spreadsheet Techniques for Evaluating the Solubility of Sparingly Soluble Salts of Weak Acids

    NASA Astrophysics Data System (ADS)

    Guinón, José L.; García-Antón, José; Pérez-Herranz, Valentín

    1999-08-01

    A spreadsheet of Microsoft Excel for determining the solubility of sparingly soluble salts is described. The chart and worksheet are shown simultaneously on the screen. The worksheet can be used for any salt by merely changing the data for the solubility product constant and ionization constants. Practical examples of calculations are given and discussed.

  8. Surfactant-free solid dispersion of fat-soluble flavour in an amorphous sugar matrix.

    PubMed

    Satoh, Tomo; Hidaka, Fumihiro; Miyake, Kento; Yoshiyama, Natsuki; Takeda, Koji; Matsuura, Tsutashi; Imanaka, Hiroyuki; Ishida, Naoyuki; Imamura, Koreyoshi

    2016-04-15

    A solid dispersion technique to homogeneously disperse hydrophobic ingredients in a water-soluble solid without using surfactant was examined as follows: first, freeze-dried amorphous sugar was dissolved in an organic medium that contained a soluble model hydrophobic component. Second, the mixed solution of sugar and the model hydrophobic component was vacuum dried into a solid (solid dispersion). Methanol and six fat-soluble flavours, including cinnamaldehyde, were used as organic media and model hydrophobic components. The retention of flavours in the solid dispersion during drying and storage under vacuum was evaluated. The amorphised disaccharides dissolved in methanol up to 100mg/mL, even temporarily (20s to 10 days) and could be solidified without any evidence of crystallisation and segregation from flavour. The solid dispersion, prepared using α-maltose usually showed 65-95% flavour retention during drying (and storage for cinnamaldehyde), whereas ⩾ 50% of the flavour was lost when the flavour was O/W emulsified with a surfactant and then freeze-dried with sugar.

  9. Surfactant-free solid dispersion of fat-soluble flavour in an amorphous sugar matrix.

    PubMed

    Satoh, Tomo; Hidaka, Fumihiro; Miyake, Kento; Yoshiyama, Natsuki; Takeda, Koji; Matsuura, Tsutashi; Imanaka, Hiroyuki; Ishida, Naoyuki; Imamura, Koreyoshi

    2016-04-15

    A solid dispersion technique to homogeneously disperse hydrophobic ingredients in a water-soluble solid without using surfactant was examined as follows: first, freeze-dried amorphous sugar was dissolved in an organic medium that contained a soluble model hydrophobic component. Second, the mixed solution of sugar and the model hydrophobic component was vacuum dried into a solid (solid dispersion). Methanol and six fat-soluble flavours, including cinnamaldehyde, were used as organic media and model hydrophobic components. The retention of flavours in the solid dispersion during drying and storage under vacuum was evaluated. The amorphised disaccharides dissolved in methanol up to 100mg/mL, even temporarily (20s to 10 days) and could be solidified without any evidence of crystallisation and segregation from flavour. The solid dispersion, prepared using α-maltose usually showed 65-95% flavour retention during drying (and storage for cinnamaldehyde), whereas ⩾ 50% of the flavour was lost when the flavour was O/W emulsified with a surfactant and then freeze-dried with sugar. PMID:26675850

  10. Improvement of solubility and dissolution rate of poorly water-soluble salicylic acid by a spray-drying technique.

    PubMed

    Kawashima, Y; Saito, M; Takenaka, H

    1975-01-01

    Spray drying techniques have been applied to improve the solubility and dissolution rate of poorly water-soluble salicylic acid. Spray drying of the acid dispersed in acacia solutions resulted in as much as a 50% improvement in the solubility of the product. Solubility improvement was closely related not only to the concentration of acacia but also the amount of amorphous material in the spray-dried products. The heat of solution was inversely related to these parameters. The dissolution rate of spray-dried product was almost instantaneous being about 60 times faster than that of the original powder. A great improvement in the wettability of the spray-dried material seemed to be mainly responsible for the increase of dissolution rate.

  11. Effects of ground corn particle size on ethanol yield and thin stillage soluble solids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of ground corn particle size on ethanol yield and soluble solids in thin stillage were evaluated using a 2-L laboratory dry-grind procedure. The procedure was optimized for grinding, liquefaction, saccharification, and fermentation parameters. The optimized procedure was reproducible wi...

  12. Le Chatelier's Principle: The Effect of Temperature on the Solubility of Solids in Liquids.

    ERIC Educational Resources Information Center

    Brice, L. K.

    1983-01-01

    Provides a rigorous but straightforward thermodynamic treatment of the temperature dependence of the solubility of solids in liquids that is suitable for presentation to undergraduates, suggesting how to approach the qualitative aspects of the subject for freshmen. Considers unsolvated/solvated solutes and Le Chatelier's principle. (JN)

  13. Uptake of Hypobromous Acid (HOBr) by Aqueous Sulfuric Acid Solutions: Low-Temperature Solubility and Reaction

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Michelsen, Rebecca R.; Ashbourn, Samatha F. M.; Rammer, Thomas A.; Golden, David M.

    2005-01-01

    Hypobromous acid (HOBr) is a key species linking inorganic bromine to the chlorine and odd hydrogen chemical families. We have measured the solubility of HOBr in 45 - 70 wt% sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosol composition. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, with an effective Henry's law coefficient, H* = 10(exp 4) - 10(exp 7) mol/L/atm. H* is inversely dependent on temperature, with Delta H = -46.2 kJ/mol and Delta S = -106.2 J/mol/K for 55 - 70 wt% H2SO4 solutions. Our study includes temperatures which overlap both previous measurements of HOBr solubility. For uptake into aqueous 45 wt% H2SO4, the solubility can be described by log H* = 3665/T - 10.63. For 55 - 70 wt% H2SO4, log H* = 2412/T - 5.55. At temperatures colder than approx. 213 K, the solubility of HOBr in 45 wt% H2SO4 is noticeably larger than in 70 wt% H2SO4. The solubility of HOBr is comparable to that of HBr, indicating that upper tropospheric and lower stratospheric aerosols should contain equilibrium concentrations of HOBr which equal or exceed those of HBr. Our measurements indicate chemical reaction of HOBr upon uptake into aqueous sulfuric acid in the presence of other brominated gases followed by evolution of gaseous products including Br2O and Br2, particularly at 70 wt% H2SO4.

  14. Porous Silica-Supported Solid Lipid Particles for Enhanced Solubilization of Poorly Soluble Drugs.

    PubMed

    Yasmin, Rokhsana; Rao, Shasha; Bremmell, Kristen E; Prestidge, Clive A

    2016-07-01

    Low dissolution of drugs in the intestinal fluid can limit their effectiveness in oral therapies. Here, a novel porous silica-supported solid lipid system was developed to optimize the oral delivery of drugs with limited aqueous solubility. Using lovastatin (LOV) as the model poorly water-soluble drug, two porous silica-supported solid lipid systems (SSL-A and SSL-S) were fabricated from solid lipid (glyceryl monostearate, GMS) and nanoporous silica particles Aerosil 380 (silica-A) and Syloid 244FP (silica-S) via immersion/solvent evaporation. SSL particles demonstrated significantly higher rate and extent of lipolysis in comparison with the pure solid lipid, depending on the lipid loading levels and the morphology. The highest lipid digestion was observed when silica-S was loaded with 34% (w/w) solid lipid, and differential scanning calorimeter (DSC) analysis confirmed the encapsulation of up to 2% (w/w) non-crystalline LOV in this optimal SSL-S formulation. Drug dissolution under non-digesting intestinal conditions revealed a three- to sixfold increase in dissolution efficiencies when compared to the unformulated drug and a LOV-lipid suspension. Furthermore, the SSL-S provided superior drug solubilization under simulated intestinal digesting condition in comparison with the drug-lipid suspension and drug-loaded silica. Therefore, solid lipid and nanoporous silica provides a synergistic effect on optimizing the solubilization of poorly water-soluble compound and the solid lipid-based porous carrier system provides a promising delivery approach to overcome the oral delivery challenges of poorly water-soluble drugs.

  15. Porous Silica-Supported Solid Lipid Particles for Enhanced Solubilization of Poorly Soluble Drugs.

    PubMed

    Yasmin, Rokhsana; Rao, Shasha; Bremmell, Kristen E; Prestidge, Clive A

    2016-07-01

    Low dissolution of drugs in the intestinal fluid can limit their effectiveness in oral therapies. Here, a novel porous silica-supported solid lipid system was developed to optimize the oral delivery of drugs with limited aqueous solubility. Using lovastatin (LOV) as the model poorly water-soluble drug, two porous silica-supported solid lipid systems (SSL-A and SSL-S) were fabricated from solid lipid (glyceryl monostearate, GMS) and nanoporous silica particles Aerosil 380 (silica-A) and Syloid 244FP (silica-S) via immersion/solvent evaporation. SSL particles demonstrated significantly higher rate and extent of lipolysis in comparison with the pure solid lipid, depending on the lipid loading levels and the morphology. The highest lipid digestion was observed when silica-S was loaded with 34% (w/w) solid lipid, and differential scanning calorimeter (DSC) analysis confirmed the encapsulation of up to 2% (w/w) non-crystalline LOV in this optimal SSL-S formulation. Drug dissolution under non-digesting intestinal conditions revealed a three- to sixfold increase in dissolution efficiencies when compared to the unformulated drug and a LOV-lipid suspension. Furthermore, the SSL-S provided superior drug solubilization under simulated intestinal digesting condition in comparison with the drug-lipid suspension and drug-loaded silica. Therefore, solid lipid and nanoporous silica provides a synergistic effect on optimizing the solubilization of poorly water-soluble compound and the solid lipid-based porous carrier system provides a promising delivery approach to overcome the oral delivery challenges of poorly water-soluble drugs. PMID:27048207

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

    SciTech Connect

    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.

  17. The effects of acid treatment and calcium ions on the solubility of concanavalin A

    NASA Technical Reports Server (NTRS)

    Cacioppo, Elizabeth; Pusey, Marc L.

    1992-01-01

    The effects of acid treatment (which removes Mn and Ca ions) and Ca(2+) ions on the solubility of jack-bean-meal concanavalin A were investigated using two techniques: the sitting drop technique and the microcolumn technique. It was found that the solubility of concanavalin A varied with the protein preparation procedures and with measurement techniques. Addition of Ca(2+) resulted in greatly lowered solubilities compared with the acid treated protein. The sitting drop solubilities for the recalcified protein agreed better with those reported by Mikol and Giege (1989) than with solubilities determined from column data.

  18. Crystallization of solid-state materials via decomplexation of soluble complexes

    SciTech Connect

    Doxsee, K.M.

    1998-10-01

    A variety of compounds which are at best sparingly soluble in aqueous media may be readily brought into solution through the formation of soluble coordination complexes. Modification of experimental conditions through, e.g., dilution or slow removal of the complexing agent, leads to supersaturation and, consequently, crystallization of the original solid-state phase. This technique of decomplexation crystallization, both of simple inorganic coordination complexes and of complexes with macrocyclic organic chelating agents, offers the opportunity both to effect the recrystallization of sparingly soluble species and to modify their crystal morphology. Similarly, precursors for solid-state materials may be solubilized in nonaqueous solvents through the formation of soluble complexes and then allowed to undergo reaction crystallization, allowing the examination of both solvent effects and chelation effects on the morphology and phase of the resulting solid-state materials. These effects are often dramatic, and such complexation-mediated crystallization approaches offer promise for the facile preparation of metastable phases from simple precursors under ambient conditions.

  19. A solid form of ambazone with lactic acid

    NASA Astrophysics Data System (ADS)

    Borodi, Gh.; Muresan-Pop, M.; Kacsó, I.; Bratu, I.

    2012-02-01

    In recent years, much research has been carried out on the preparation of pharmaceutical solid forms due to their improved physical-chemical parameters such as solubility, dissolution rate of the drug, chemical stability, melting point and hygroscopic parameter. The aim of this study was to obtain and to investigate the structural properties of the ambazone (AMB) with lactic acid (LA) solid form. The solid form was obtained starting from the mixture of ambazone with lactic acid (1:1), by grinding method at constant temperature. The obtained compound was investigated via X-ray powder diffraction (PXRD), thermal analysis (DSC, TG-DTA) and infrared (FTIR) spectroscopy. The difference between the patterns of AMB•LA and of the starting compounds evidenced a new compound. Using X-ray powder diffraction method, by indexing procedure the unit cell and the lattice parameters were determined. Thermal and FTIR measurements on the pure compounds and on the (1:1) ground mixture of AMB with LA confirm the new salt form formation.

  20. Small acid soluble proteins for rapid spore identification.

    SciTech Connect

    Branda, Steven S.; Lane, Todd W.; VanderNoot, Victoria A.; Jokerst, Amanda S.

    2006-12-01

    This one year LDRD addressed the problem of rapid characterization of bacterial spores such as those from the genus Bacillus, the group that contains pathogenic spores such as B. anthracis. In this effort we addressed the feasibility of using a proteomics based approach to spore characterization using a subset of conserved spore proteins known as the small acid soluble proteins or SASPs. We proposed developing techniques that built on our previous expertise in microseparations to rapidly characterize or identify spores. An alternative SASP extraction method was developed that was amenable to both the subsequent fluorescent labeling required for laser-induced fluorescence detection and the low ionic strength requirements for isoelectric focusing. For the microseparations, both capillary isoelectric focusing and chip gel electrophoresis were employed. A variety of methods were evaluated to improve the molecular weight resolution for the SASPs, which are in a molecular weight range that is not well resolved by the current methods. Isoelectric focusing was optimized and employed to resolve the SASPs using UV absorbance detection. Proteomic signatures of native wild type Bacillus spores and clones genetically engineered to produce altered SASP patterns were assessed by slab gel electrophoresis, capillary isoelectric focusing with absorbance detection as well as microchip based gel electrophoresis employing sensitive laser-induced fluorescence detection.

  1. A method for rapid liquid-solid phase solubility measurements using the protein lysozyme

    NASA Technical Reports Server (NTRS)

    Pusey, Marc L.; Gernert, Kim

    1988-01-01

    Using hen's egg white lysozyme crystals as the test material, a simple system was developed for rapidly and unambiguously determining solubilities in (aqueous) solutions. The system is based upon a maximization of the solid surface area available for solute transfer to or from the solution, and a minimization of both the solution volume which must be equilibrated and the distance over which diffusive solute exchange occurs. This technique is further enhanced by using duplicate test systems which differ only in that one approaches equilibrium from an oversaturated solution, while the other from an undersaturated solution. Thus, the resulting data pair brackets the solubility value. In practical terms, the data points are found to usually be within 3 percent of each other, and individual solubility data points may usually be made at this resolution within 8-24 h depending upon the temperature change made since the previous determination.

  2. Investigation of the solubility enhancement mechanism of rebaudioside D using a solid dispersion technique with potassium sorbate as a carrier.

    PubMed

    Pang, Shintaro; Ma, Changchu; Zhang, Naijie; He, Lili

    2015-05-01

    Rebaudioside (Reb) D is a high intensity, natural sweetener that shows great potential for substituting sugar in sweetened beverages. However, Reb D is poorly water soluble, and thus, a solid dispersion technique was recently established to enhance its solubility. The purpose of this study was to elucidate the solubility enhancement mechanism of this solid dispersion material by employing Scanning Electron Microscopy (SEM), Raman spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR) and X-ray Diffraction (XRD). Potassium sorbate (KS) was chosen as the carrier and two different concentration ratios were investigated as solid dispersions (SD) and as physical mixtures (PM). Our data demonstrated the possible mechanism for enhancing solubility through solid dispersion through increased surface area/volume ratio and hydrogen bonding between Reb D and KS. The interaction between the two components were also related to the different concentration ratios, therefore an optimisation of the ratio is important to produce a soluble and stable complex. PMID:25529720

  3. Improvement of solubility and dissolution properties of clotrimazole by solid dispersions and inclusion complexes.

    PubMed

    Balata, Gehan; Mahdi, M; Bakera, Rania Abu

    2011-09-01

    Solid dispersions of a slightly water-soluble drug, clotrimazole, were prepared in different weight ratios using polyethyleneglycol 4000 and different molecular weight polyvinyl pyrrolidones as carriers. Moreover, binary and ternary β-cyclodextrin complexes were prepared in different molar ratios. Both solid dispersions and β-cyclodextrin complexes were prepared by solvent evaporation technique. A phase solubility method was used to evaluate the effect of the tested carriers on the aqueous solubility of clotrimazole. The dissolution of all the preparations was tested using the USP paddle method. The selected solid dispersions and inclusion complexes were characterized by differential scanning calorimetry and X-ray powder diffractometry studies, and results clarified the role of the tested carriers in decreasing the crystallinity of clotrimazole and complexing abilities. Based on physical characters and in vitro drug release pattern, polyvinylpyrrolidone solid dispersions (1:1 weight ratio) and ternary cyclodextrin complexes (clotrimazole-β-cyclodextrin complexes with either polymer, 1:1 molar ratio) were selected as ideal batches for suppositories. Suppocire AM/50 mg carbopol 940, was chosen as a suppository base and the suppositories were prepared by molding technique. The prepared suppositories were characterized for weight variation, softening time and drug content. All these properties were found to be ideal. The in vitro drug release pattern was determined in citrate buffer (pH 4.5) containing 1% sodium lauryl sulfate. The in vitro release of clotrimazole from its solid dispersions and inclusion complexes incorporated suppositories was markedly improved when compared to the intact drug incorporated suppositories. Polyvinyl pyrrolidone solid dispersions incorporated suppositories were found to possess excellent antifungal activity. PMID:22923864

  4. Fast Measurement of Soluble Solid Content in Mango Based on Visible and Infrared Spectroscopy Technique

    NASA Astrophysics Data System (ADS)

    Yu, Jiajia; He, Yong

    Mango is a kind of popular tropical fruit, and the soluble solid content is an important in this study visible and short-wave near-infrared spectroscopy (VIS/SWNIR) technique was applied. For sake of investigating the feasibility of using VIS/SWNIR spectroscopy to measure the soluble solid content in mango, and validating the performance of selected sensitive bands, for the calibration set was formed by 135 mango samples, while the remaining 45 mango samples for the prediction set. The combination of partial least squares and backpropagation artificial neural networks (PLS-BP) was used to calculate the prediction model based on raw spectrum data. Based on PLS-BP, the determination coefficient for prediction (Rp) was 0.757 and root mean square and the process is simple and easy to operate. Compared with the Partial least squares (PLS) result, the performance of PLS-BP is better.

  5. Extraction of soluble substances from organic solid municipal waste to increase methane production.

    PubMed

    Campuzano, Rosalinda; González-Martínez, Simón

    2015-02-01

    This work deals with the analysis of the methane production from Mexico City's urban organic wastes after separating soluble from suspended substances. Water was used to extract soluble substances under three different water to waste ratios and after three extraction procedures. Methane production was measured at 35 °C during 21 days using a commercial methane potential testing device. Results indicate that volatile solids extraction increases with dilution rate to a maximum of 40% at 20 °C and to 43% at 93 °C. The extracts methane production increases with the dilution rate as a result of enhanced dissolved solids extraction. The combined (extract and bagasse) methane production reached, in 6 days, 66% of the total methane produced in 21 days. The highest methane production rates were measured during the first six days.

  6. Improving Co-Amorphous Drug Formulations by the Addition of the Highly Water Soluble Amino Acid, Proline

    PubMed Central

    Jensen, Katrine Tarp; Löbmann, Korbinian; Rades, Thomas; Grohganz, Holger

    2014-01-01

    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. PMID:25025400

  7. A review of experimental methods for solid solubility determination in cryogenic systems

    NASA Astrophysics Data System (ADS)

    De Stefani, V.; Baba-Ahmed, A.; Richon, D.

    2004-09-01

    Over the past years, there have been a number of serious explosions in air industry, which have resulted in workers injuries and fatalities. At the same time, there has been an increase in the use of air separation products for industrial activities. The quality of air entering an air separation plant is of crucial importance for its safe and reliable operation and the interest in the solubility data of solids in cryogenic liquid solvents is closely connected to the problem of impurities accumulation in the process plant and storage tanks. Such accumulations, especially in liquid oxygen, may cause fouling and blockage in heat exchangers and pipelines and they may eventually cause serious explosions. For this reason the air contaminants composition in liquid oxygen must be determined with great precision. This paper aims at reviewing experimental methods for determining the solubility of solid compounds that may be present in the cryogenic liquefaction processing of air distillation. A review of the literature data on solubility of solids in liquid oxygen and nitrogen is included as well. Emphasis is given to the difficulties in setting-up measuring apparatuses working at extreme conditions, i.e. low compositions and low temperatures.

  8. Determination of soluble solids content in apple products by terahertz time-domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Hao, Guohui; Liu, Jianjun; Hong, Zhi

    2011-08-01

    Soluble solids content is an important index for fruit quality. One of the traditional methods in determining soluble solids content of fruits is refractometry which measures the refractive index in visible or near infrared. Here we reported the use of terahertz time-domain transmission spectroscopy (THz-TDTS) technique for the determination of soluble solids content in apple products. Not only the refractive index, but also the absorption coefficient is used in regression model. In method one, sucrose solutions were for the calibration set , root mean square of validation set (RMSEP) was 0.168% for absorption coefficient model, 0.741% for refractive index model. In method two, apple products were for the calibration set, RMSEP was 0.143% for absorption coefficient model, 0.648% for refractive index model. Less absolute error of 0.2% between predicted and refractometer value has been both obtained from two methods with absorption coefficient model. This result proved the THz-TDS technique is quite potential for nondestructive detection on food quality.

  9. A Green Analytical Method Using Ultrasound in Sample Preparation for the Flow Injection Determination of Iron, Manganese, and Zinc in Soluble Solid Samples by Flame Atomic Absorption Spectrometry

    PubMed Central

    Yebra, M. Carmen

    2012-01-01

    A simple and rapid analytical method was developed for the determination of iron, manganese, and zinc in soluble solid samples. The method is based on continuous ultrasonic water dissolution of the sample (5–30 mg) at room temperature followed by flow injection flame atomic absorption spectrometric determination. A good precision of the whole procedure (1.2–4.6%) and a sample throughput of ca. 25 samples h–1 were obtained. The proposed green analytical method has been successfully applied for the determination of iron, manganese, and zinc in soluble solid food samples (soluble cocoa and soluble coffee) and pharmaceutical preparations (multivitamin tablets). The ranges of concentrations found were 21.4–25.61 μg g−1 for iron, 5.74–18.30 μg g−1 for manganese, and 33.27–57.90 μg g−1 for zinc in soluble solid food samples and 3.75–9.90 μg g−1 for iron, 0.47–5.05 μg g−1 for manganese, and 1.55–15.12 μg g−1 for zinc in multivitamin tablets. The accuracy of the proposed method was established by a comparison with the conventional wet acid digestion method using a paired t-test, indicating the absence of systematic errors. PMID:22567553

  10. A green analytical method using ultrasound in sample preparation for the flow injection determination of iron, manganese, and zinc in soluble solid samples by flame atomic absorption spectrometry.

    PubMed

    Yebra, M Carmen

    2012-01-01

    A simple and rapid analytical method was developed for the determination of iron, manganese, and zinc in soluble solid samples. The method is based on continuous ultrasonic water dissolution of the sample (5-30 mg) at room temperature followed by flow injection flame atomic absorption spectrometric determination. A good precision of the whole procedure (1.2-4.6%) and a sample throughput of ca. 25 samples h(-1) were obtained. The proposed green analytical method has been successfully applied for the determination of iron, manganese, and zinc in soluble solid food samples (soluble cocoa and soluble coffee) and pharmaceutical preparations (multivitamin tablets). The ranges of concentrations found were 21.4-25.61 μg g(-1) for iron, 5.74-18.30 μg g(-1) for manganese, and 33.27-57.90 μg g(-1) for zinc in soluble solid food samples and 3.75-9.90 μg g(-1) for iron, 0.47-5.05 μg g(-1) for manganese, and 1.55-15.12 μg g(-1) for zinc in multivitamin tablets. The accuracy of the proposed method was established by a comparison with the conventional wet acid digestion method using a paired t-test, indicating the absence of systematic errors. PMID:22567553

  11. Salt and cocrystals of sildenafil with dicarboxylic acids: solubility and pharmacokinetic advantage of the glutarate salt.

    PubMed

    Sanphui, Palash; Tothadi, Srinu; Ganguly, Somnath; Desiraju, Gautam R

    2013-12-01

    Sildenafil is a drug used to treat erectile dysfunction and pulmonary arterial hypertension. Because of poor aqueous solubility of the drug, the citrate salt, with improved solubility and pharmacokinetics, has been marketed. However, the citrate salt requires an hour to reach its peak plasma concentration. Thus, to improve solubility and bioavailability characteristics, cocrystals and salts of the drug have been prepared by treating aliphatic dicarboxylic acids with sildenafil; the N-methylated piperazine of the drug molecule interacts with the carboxyl group of the acid to form a heterosynthon. Salts are formed with oxalic and fumaric acid; salt monoanions are formed with succinic and glutaric acid. Sildenafil forms cocrystals with longer chain dicarboxylic acids such as adipic, pimelic, suberic, and sebacic acids. Auxiliary stabilization via C-H···O interactions is also present in these cocrystals and salts. Solubility experiments of sildenafil cocrystal/salts were carried out in 0.1N HCl aqueous medium and compared with the solubility of the citrate salt. The glutarate salt and pimelic acid cocrystal dissolve faster than the citrate salt in a two hour dissolution experiment. The glutarate salt exhibits improved solubility (3.2-fold) compared to the citrate salt in water. Solubilities of the binary salts follow an inverse correlation with their melting points, while the solubilities of the cocrystals follow solubilities of the coformer. Pharmacokinetic studies on rats showed that the glutarate salt exhibits doubled plasma AUC values in a single dose within an hour compared to the citrate salt. The high solubility of glutaric acid, in part originating from the strained conformation of the molecule and its high permeability, may be the reason for higher plasma levels of the drug.

  12. Improving the solubility and bioavailability of dihydroartemisinin by solid dispersions and inclusion complexes.

    PubMed

    Ansari, Muhammad Tayyab; Batty, Kevin T; Iqbal, Ijaz; Sunderland, Vivian Bruce

    2011-05-01

    Dihydroartemisinin (DHA) is a poorly water-soluble drug that displays low bioavailability after oral administration. Attempts have been made to improve the solubility of DHA. Yet, no information is available concerning improved bioavailability. This study aimed to improve the water solubility of DHA by two systems: solid dispersions with polyvinylpyrrolidone (PVPK30, PVPK25, PVPK15) and inclusion complexes with hydroxypropyl-β-cyclodextrin (HPβCD), as well as improving the bioavailability of both systems. The phase transition of DHA with hydrophilic polymers was evaluated by X-ray diffraction (XRD) and differential scanning calorimetery (DSC). DHA became amorphous in DHA-HPβCD complexes and showed more amorphous behavior in XRD analyses with rise in molecular weight of PVP. Melting onset temperature of DHA decreased, while DSC thermograms revealed the peak area and enhanced enthalpy change (DH) in solid dispersions as well as inclusion complexes. DHA solubility was enhanced 84-fold in DHA-HPβCD complexes and 50-times in DHA-PVPK30. The improved solubility using the four polymers was in the following order: HPβCD > PVPK30 > PVPK25 > PVPK15. Values of area under curve (AUC) and half life (t(1/2)) of DHA-PVPK30 were highest followed by DHA-HPβCD, DHA-PVPK15 and DHA-PVPK25. V(d)/f of DHA-PVPK30 was 7-fold. DHA-HPβCD, DHA-PVPK15 and DHA-PVPK25 showed significantly different pharmacokinetic parameters compared with DHA solutions. The 95% confidence interval was meaningful in AUC and t(1/2). Pharmacokinetic parameters revealed that all four-test preparations were significantly more bioavailable than DHA alone.

  13. Water-soluble nitric-oxide-releasing acetylsalicylic acid (ASA) prodrugs.

    PubMed

    Rolando, Barbara; Lazzarato, Loretta; Donnola, Monica; Marini, Elisabetta; Joseph, Sony; Morini, Giuseppina; Pozzoli, Cristina; Fruttero, Roberta; Gasco, Alberto

    2013-07-01

    A series of water-soluble (benzoyloxy)methyl esters of acetylsalicylic acid (ASA), commonly known as aspirin, are described. The new derivatives each have alkyl chains containing a nitric oxide (NO)-releasing nitrooxy group and a solubilizing moiety bonded to the benzoyl ring. The compounds were synthesized and evaluated as ASA prodrugs. After conversion to the appropriate salt, most of the derivatives are solid at room temperature and all possess good water solubility. They are quite stable in acid solution (pH 1) and less stable at physiological pH. In human serum, these compounds are immediately metabolized by esterases, producing a mixture of ASA, salicylic acid (SA), and of the related NO-donor benzoic acids, along with other minor products. Due to ASA release, the prodrugs are capable of inhibiting collagen-induced platelet aggregation of human platelet-rich plasma. Simple NO-donor benzoic acids 3-hydroxy-4-(3-nitrooxypropoxy)benzoic acid (28) and 3-(morpholin-4-ylmethyl)-4-[3-(nitrooxy)propoxy]benzoic acid (48) were also studied as representative models of the whole class of benzoic acids formed following metabolism of the prodrugs in serum. These simplified derivatives did not trigger antiaggregatory activity when tested at 300 μM. Only 28 displays quite potent NO-dependent vasodilatatory action. Further in vivo evaluation of two selected prodrugs, {[2-(acetyloxy)benzoyl]oxy}methyl-3-[(3-[aminopropanoyl)oxy]-4-[3-(nitrooxy)propoxy]benzoate⋅HCl (38) and {[2-(acetyloxy)benzoyl]oxy}methyl 3-(morpholin-4-ylmethyl)-4-[3-(nitrooxy)propoxy]benzoate oxalate (49), revealed that their anti-inflammatory activities are similar to that of ASA when tested in the carrageenan-induced paw edema assay in rats. The gastrotoxicity of the two prodrugs was also determined to be lower than that of ASA in a lesion model in rats. Taken together, these results indicated that these NO-donor ASA prodrugs warrant further investigation for clinical application.

  14. Solubility of small-chain carboxylic acids in supercritical carbon dioxide

    DOE PAGES

    Sparks, Darrell L.; Estevez, L. Antonio; Hernandez, Rafael; McEwen, Jason; French, Todd

    2010-07-08

    The solubility of heptanoic acid and octanoic acid in supercritical carbon dioxide has been determined at temperatures of (313.15, 323.15, and 333.15) K over a pressure range of (8.5 to 30.0) MPa, depending upon the solute. The solubility of heptanoic acid ranged from a solute concentration of (0.08 ± 0.03) kg • m-3 (T = 323.15 K, p = 8.5 MPa) to (147 ± 0.2) kg • m-3 (T = 323.15 K, p = 20.0 MPa). The lowest octanoic acid solubility obtained was a solute concentration of (0.40 ± 0.1) kg • m-3 (T = 333.15 K, p = 10.0more » MPa), while the highest solute concentration was (151 ± 2) kg • m-3 (T = 333.15 K, p = 26.7 MPa). In addition, solubility experiments were performed for nonanoic acid in supercritical carbon dioxide at 323.15 K and pressures of (10.0 to 30.0) MPa to add to the solubility data previously published by the authors. In general, carboxylic acid solubility increased with increasing solvent density. The results also showed that the solubility of the solutes decreased with increasing molar mass at constant supercritical-fluid density. Additionally, the efficacy of Chrastil's equation and other density-based models was evaluated for each fatty acid.« less

  15. Solubility of small-chain carboxylic acids in supercritical carbon dioxide

    SciTech Connect

    Sparks, Darrell L.; Estevez, L. Antonio; Hernandez, Rafael; McEwen, Jason; French, Todd

    2010-07-08

    The solubility of heptanoic acid and octanoic acid in supercritical carbon dioxide has been determined at temperatures of (313.15, 323.15, and 333.15) K over a pressure range of (8.5 to 30.0) MPa, depending upon the solute. The solubility of heptanoic acid ranged from a solute concentration of (0.08 ± 0.03) kg • m-3 (T = 323.15 K, p = 8.5 MPa) to (147 ± 0.2) kg • m-3 (T = 323.15 K, p = 20.0 MPa). The lowest octanoic acid solubility obtained was a solute concentration of (0.40 ± 0.1) kg • m-3 (T = 333.15 K, p = 10.0 MPa), while the highest solute concentration was (151 ± 2) kg • m-3 (T = 333.15 K, p = 26.7 MPa). In addition, solubility experiments were performed for nonanoic acid in supercritical carbon dioxide at 323.15 K and pressures of (10.0 to 30.0) MPa to add to the solubility data previously published by the authors. In general, carboxylic acid solubility increased with increasing solvent density. The results also showed that the solubility of the solutes decreased with increasing molar mass at constant supercritical-fluid density. Additionally, the efficacy of Chrastil's equation and other density-based models was evaluated for each fatty acid.

  16. Preparation and solid-state characterization of ball milled saquinavir mesylate for solubility enhancement.

    PubMed

    Branham, Michael Lee; Moyo, Thomas; Govender, Thirumala

    2012-01-01

    Saquinavir is an anti-retroviral drug with very low oral bioavailability (e.g. 0.7-4.0%) due to its affinity toward efflux transporters (P-gp) and metabolic enzymes (CYP3A4). The aim of this study was to characterize the effects of high-energy ball milling on saquinavir solid-state characteristics and aqueous solubility for the design of effective buccal drug delivery systems. The solubility of saquinavir mesylate was evaluated in simulated saliva before and after milling for 1, 3, 15, 30, 50, and 60 h. To elucidate changes in crystallinity and long-range structure in the drug, analyses of the milled powders were performed using XRD, ATR-IR, DSC/TGA, BET surface area, EDX and SEM. In addition, the effects of milling time on saquinavir solubility were statistically correlated using repeated measures ANOVA. Results of this study indicate that the milling of saquinavir mesylate produces nanoporous particles with unique surface structures, thermal properties, and increased aqueous solubility. Optimal milling time occurred at 3h and corresponded to a 9-fold solubility enhancement in simulated saliva. Thermal analysis revealed only a slight decrease in melting point (T(m)) from 242 °C to 236 °C after 60 h milling. XRD diffractograms indicate a gradual crystalline-to-amorphous transition with some residual crystallinity remaining after 60 h milling time. Unstable polymorphic structures appeared between 15 and 30 h which were converted to more stable isomorphs at 60 h. Aggregate formation also seems to occur after 15 h but no metal contamination of the drug was observed during the milling process as determined by EDX analysis. In conclusion, high-energy ball milling may be a method of choice for improving the solubility of saquinavir and facilitating novel drug formulations design.

  17. Interconnection between the protein solubility and amino acid and dipeptide compositions.

    PubMed

    Niu, Xiaohui; Li, Nana; Chen, Dinyan; Wang, Zengzhen

    2013-01-01

    Obtaining soluble proteins in sufficient concentrations helps increase the overall success rate in various experimental studies. Protein solubility is an individual trait ultimately determined by its primary protein sequence. Exploring the interconnection between the protein solubility and the compositions of protein sequence is instrumental for setting priorities on targets in large scale proteomics projects. In this paper, amino acid composition (20 dimensions) and the dipeptide composition (400 dimensions) were extracted to form the total candidate feature pool (420 dimensions), and each feature was selected into the feature vectors one by one, which were sorted by the absolute value of the correlation coefficient. Finally, we evaluated and recorded the 420 results of Support Vector Machine (SVM) as the prediction engine. According to the results of SVM, the first 208 features were chosen from the 420 dimensions, which were considered as the efficient ones. By analyzing the composition of the former 208 features, we found that the protein solubility was significantly influenced by the occurrence frequencies of the acidic amino acids, basic amino acids, non-polar hydrophobic amino acids and the two polar neutral amino acids(C, Q) in the protein sequences. Additionally, we detected that the dipeptides composed by the acidic amino acids (D, E) and basic amino acids (K, R and H), especially the dipeptide composed by the acidic amino acids (D, E), had strong interconnection with the protein solubility.

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

    PubMed

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

    2008-08-01

    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.

  19. Revealing facts behind spray dried solid dispersion technology used for solubility enhancement

    PubMed Central

    Patel, Bhavesh B.; Patel, Jayvadan K.; Chakraborty, Subhashis; Shukla, Dali

    2013-01-01

    Poor solubility and bioavailability of an existing or newly synthesized drug always pose challenge in the development of efficient pharmaceutical formulation. Numerous technologies can be used to improve the solubility and among them amorphous solid dispersion based spray drying technology can be successfully useful for development of product from lab scale to commercial scale with a wide range of powder characteristics. Current review deals with the importance of spray drying technology in drug delivery, basically for solubility and bioavailability enhancement. Role of additives, selection of polymer, effect of process and formulation parameters, scale up optimization, and IVIVC have been covered to gain the interest of readers about the technology. Design of experiment (DoE) to optimize the spray drying process has been covered in the review. A lot more research work is required to evaluate spray drying as a technology for screening the right polymer for solid dispersion, especially to overcome the issue related to drug re-crystallization and to achieve a stable product both in vitro and in vivo. Based on the recent FDA recommendation, the need of the hour is also to adopt Quality by Design approach in the manufacturing process to carefully optimize the spray drying technology for its smooth transfer from lab scale to commercial scale. PMID:27134535

  20. Manganese ore tailing: optimization of acid leaching conditions and recovery of soluble manganese.

    PubMed

    Santos, Olívia de Souza Heleno; Carvalho, Cornélio de Freitas; Silva, Gilmare Antônia da; Santos, Cláudio Gouvêa Dos

    2015-01-01

    Manganese recovery from industrial ore processing waste by means of leaching with sulfuric acid was the objective of this study. Experimental conditions were optimized by multivariate experimental design approaches. In order to study the factors affecting leaching, a screening step was used involving a full factorial design with central point for three variables in two levels (2(3)). The three variables studied were leaching time, concentration of sulfuric acid and sample amount. The three factors screened were shown to be relevant and therefore a Doehlert design was applied to determine the best working conditions for leaching and to build the response surface. By applying the best leaching conditions, the concentrations of 12.80 and 13.64 %w/w of manganese for the global sample and for the fraction -44 + 37 μm, respectively, were found. Microbeads of chitosan were tested for removal of leachate acidity and recovering of soluble manganese. Manganese recovery from the leachate was 95.4%. Upon drying the leachate, a solid containing mostly manganese sulfate was obtained, showing that the proposed optimized method is efficient for manganese recovery from ore tailings.

  1. Solid solubility, phase transitions, thermal expansion, and compressibility in Sc1-xAlxF3

    NASA Astrophysics Data System (ADS)

    Morelock, Cody R.; Gallington, Leighanne C.; Wilkinson, Angus P.

    2015-02-01

    With the goal of thermal expansion control, the synthesis and properties of Sc1-xAlxF3 were investigated. The solubility limit of AlF3 in ScF3 at ~1340 K is ~50%. Solid solutions (x≤0.50) were characterized by synchrotron powder diffraction at ambient pressure between 100 and 900 K and at pressures <0.414 GPa while heating from 298 to 523 K. A phase transition from cubic to rhombohedral is observed. The transition temperature increases smoothly with Al3+ content, approaching 500 K at the solid solubility limit, and also upon compression at fixed Al3+ content. The slope of the pressure-temperature phase boundary is ~0.5 K MPa-1, which is steep relative to that for most symmetry-lowering phase transitions in perovskites. The volume coefficient of thermal expansion (CTE) for the rhombohedral phase is strongly positive, but the cubic-phase CTE varies from negative (x<0.15) to near-zero (x=0.15) to positive (x>0.20) between ~600 and 800 K. The cubic solid solutions elastically stiffen on heating, while Al3+ substitution causes softening at a given temperature.

  2. Calculation of resonance Raman excitation profiles for soluble and solid trans-polyacetylene

    NASA Astrophysics Data System (ADS)

    Maisuradze, Gia G.; Bowmaker, Graham A.; Cooney, Ralph P.

    1998-05-01

    On the basis of previously developed theory, a quantitative analysis of the experimental data for sliced RREPs of soluble and solid trans-PA is undertaken. The effect of inhomogeneous environmental broadening of RREPs of a solute molecule due to the solvent-molecule interactions and of molecules in the solid due to differences in chain lengths is investigated. The role of the diagonal and non-diagonal terms of the scattering matrix is discussed. The method is applied to the analysis of experimental data of Cataliotti et al. for soluble trans-PA (R.S. Cataliotti, G. Paliani, G. Dellepiane, S. Fuso, S. Destri, L. Piseri, R. Tubino, J. Chem. Phys. 82 (1985) 2223) and of Lauchlan et al. for solid trans-PA (L. Lauchlan, S.P. Chen, S. Etemad, M. Kletter, A.J. Heeger, A.G. MacDiarmid, Phys. Rev. B 27 (1983) 2301). In both cases the major contribution to the broadening of the RREPs comes from an inhomogeneous distribution of the electronic energies.

  3. Near Infrared Spectral Linearisation in Quantifying Soluble Solids Content of Intact Carambola

    PubMed Central

    Omar, Ahmad Fairuz; MatJafri, Mohd Zubir

    2013-01-01

    This study presents a novel application of near infrared (NIR) spectral linearisation for measuring the soluble solids content (SSC) of carambola fruits. NIR spectra were measured using reflectance and interactance methods. In this study, only the interactance measurement technique successfully generated a reliable measurement result with a coefficient of determination of (R2) = 0.724 and a root mean square error of prediction for (RMSEP) = 0.461° Brix. The results from this technique produced a highly accurate and stable prediction model compared with multiple linear regression techniques. PMID:23584118

  4. Near infrared spectral linearisation in quantifying soluble solids content of intact carambola.

    PubMed

    Omar, Ahmad Fairuz; MatJafri, Mohd Zubir

    2013-04-12

    This study presents a novel application of near infrared (NIR) spectral linearisation for measuring the soluble solids content (SSC) of carambola fruits. NIR spectra were measured using reflectance and interactance methods. In this study, only the interactance measurement technique successfully generated a reliable measurement result with a coefficient of determination of (R2) = 0.724 and a root mean square error of prediction for (RMSEP) = 0.461° Brix. The results from this technique produced a highly accurate and stable prediction model compared with multiple linear regression techniques.

  5. Near infrared spectral linearisation in quantifying soluble solids content of intact carambola.

    PubMed

    Omar, Ahmad Fairuz; MatJafri, Mohd Zubir

    2013-01-01

    This study presents a novel application of near infrared (NIR) spectral linearisation for measuring the soluble solids content (SSC) of carambola fruits. NIR spectra were measured using reflectance and interactance methods. In this study, only the interactance measurement technique successfully generated a reliable measurement result with a coefficient of determination of (R2) = 0.724 and a root mean square error of prediction for (RMSEP) = 0.461° Brix. The results from this technique produced a highly accurate and stable prediction model compared with multiple linear regression techniques. PMID:23584118

  6. Preparation and investigation of mefenamic acid - polyethylene glycol - sucrose ester solid dispersions.

    PubMed

    Fülöp, Ibolya; Gyéresi, Árpád; Kiss, Lóránd; Deli, Mária A; Croitoru, Mircea Dumitru; Szabó-Révész, Piroska; Aigner, Zoltán

    2015-12-01

    Mefenamic acid (MA) is a widely used non-steroidal antiinflammatory (NSAID) drug. The adverse effects typical of NSAIDs are also present in the case of MA, partly due to its low water solubility. The aim of this study was to increase the water solubility of MA in order to influence its absorption and bioavailability. Solid dispersions of MA were prepared by the melting method using polyethylene glycol 6000 and different types (laurate, D-1216; palmitate, P-1670; stearate, S-1670) and amounts of sucrose esters as carriers. The X-ray diffraction results show that MA crystals were not present in the products. Dissolution tests carried out in artificial intestinal juice showed that the product containing 10 % D-1216 increased water solubility about 3 times. The apparent permeability coefficient of MA across human Caco-2 intestinal epithelial cell layers was high and, despite the difference in solubility, there was no further increase in drug penetration in the presence of the applied additives.

  7. Thermodynamic Solubility Profile of Carbamazepine-Cinnamic Acid Cocrystal at Different pH.

    PubMed

    Keramatnia, Fatemeh; Shayanfar, Ali; Jouyban, Abolghasem

    2015-08-01

    Pharmaceutical cocrystal formation is a direct way to dramatically influence physicochemical properties of drug substances, especially their solubility and dissolution rate. Because of their instability in the solution, thermodynamic solubility of cocrystals could not be determined in the common way like other compounds; therefore, the thermodynamic solubility is calculated through concentration of their components in the eutectic point. The objective of this study is to investigate the effect of an ionizable coformer in cocrystal with a nonionizable drug at different pH. Carbamazepine (CBZ), a nonionizable drug with cinnamic acid (CIN), which is an acidic coformer, was selected to prepare CBZ-CIN cocrystal and its thermodynamic solubility was studied in pH range 2-7. Instead of HPLC that is a costly and time-consuming method, a chemometric-based approach, net analyte signal standard addition method, was selected for simultaneous determination of CBZ and CIN in solution. The result showed that, as pH increases, CIN ionization leads to change in CBZ-CIN cocrystal solubility and stability in solution. In addition, the results of this study indicated that there is no significant difference between intrinsic solubility of CBZ and cocrystal despite the higher ideal solubility of cocrystal. This verifies that ideal solubility is not good parameter to predict cocrystal solubility.

  8. Structure-property relationships in halogenbenzoic acids: Thermodynamics of sublimation, fusion, vaporization and solubility.

    PubMed

    Zherikova, Kseniya V; Svetlov, Aleksey A; Kuratieva, Natalia V; Verevkin, Sergey P

    2016-10-01

    Temperature dependences of vapor pressures for 2-, 3-, and 4-bromobenzoic acid, as well as for five isomeric bromo-methylbenzoic acids were studied by the transpiration method. Melting temperatures and enthalpies of fusion for all isomeric bromo-methylbenzoic acids and 4-bromobenzoic acid were measured with a DSC. The molar enthalpies of sublimation and vaporization were derived. These data together with results available in the literature were collected and checked for internal consistency using a group-additivity procedure and results from X-ray structural diffraction studies. Specific (hydrogen bonding) interactions in the liquid and in the crystal phase of halogenbenzoic acids were quantified based on experimental values of vaporization and sublimation enthalpies. Structure-property correlations of solubilities of halogenobenzoic acids with sublimation pressures and sublimation enthalpies were developed and solubilities of bromo-benzoic acids were estimated. These new results resolve much of the ambiguity in the available thermochemical and solubility data on bromobenzoic acids. The approach based on structure property correlations can be applied for the assessment of water solubility of sparingly soluble drugs. PMID:27424058

  9. Thermodynamics and solubility of (UxNp1-x) O2(am) solid solution in the carbonate system

    SciTech Connect

    Rai, Dhanpat; Hess, Nancy J.; Yui, Mikazu; Felmy, Andrew R.; Moore, D. A.

    2004-12-31

    SUMMARY-The formation of a solid solution can significantly affect the solubility of a minor component. The objectives of this study were to determine the nature of U(IV) and Np(IV) solid solutions and their thermodynamic properties. For this purpose...

  10. Efficient synthesis of readily water-soluble sulfonic Acid carbamates.

    PubMed

    Idzik, Krzysztof R; Nödler, Karsten; Licha, Tobias

    2015-04-16

    A series of various readily water-soluble carbamates were synthesized with good yields. These compounds are useful chemical tracers for assessing the cooling progress in a georeservoir during geothermal power plant operation. Acylation of primary amines was carried out as well as using a solution of sodium bicarbonate and without the presence of salt. Products were characterized by 1H-NMR and 13C-NMR. Purity was confirmed through elemental analysis.

  11. Water solubility enhancement of some organic pollutants and pesticides by dissolved humic and fulvic acids

    USGS Publications Warehouse

    Chiou, C.T.; Malcolm, R.L.; Brinton, T.I.; Kile, D.E.

    1986-01-01

    Water solubility enhancements by dissolved humic and fulvic acids from soil and aquatic origins and by synthetic organic polymers have been determined for selected organic pollutants and pesticides (p,p???-DDT, 2,4,5,2???,5???-PCB, 2,4,4???-PCB, 1,2,3-trichlorobenzene, and lindane). Significant solubility enhancements of relatively water-insoluble solutes by dissolved organic matter (DOM) of soil and aquatic origins may be described in terms of a partition-like interaction of the the solutes with the microscopic organic environment of the high-molecular-weight DOM species; the apparent solute solubilities increase linearly with DOM concentration and show no competitive effect between solutes. With a given DOM sample, the solute partition coefficient (Kdom) increases with a decrease of solute solubility (Sw) or with an increase of the solute's octanol-water partition coefficient (Kow). The Kdom values of solutes with soil-derived humic acid are approximately 4 times greater than with soil fulvic acid and 5-7 times greater than with aquatic humic and fulvic acids. The effectiveness of DOM in enhancing solute solubility appears to be largely controlled by the DOM molecular size and polarity. The relative inability of high-molecular-weight poly(acrylic acids) to enhance solute solubility is attributed to their high polarities and extended chain structures that do not permit the formation of a sizable intramolecular nonpolar environment.

  12. Supercritical carbon dioxide-soluble ligands for extracting actinide metal ions from porous solids (EMSP Project Number 64965)

    SciTech Connect

    Dietz, M. L.; Barrans, Jr., R. E.; Herlinger, A. W.; Brennecke, J. F.

    2000-04-24

    The objective of this project is to develop novel, substituted diphosphonic acid ligands that can be used for supercritical carbon dioxide extraction (SCDE) of actinide ions from solid wastes. Specifically, selected diphosphonic acids, which are known to form extremely stable complexes with actinides in aqueous and organic solution, are to be rendered carbon dioxide-soluble by the introduction of appropriate alkyl- or silicon-containing substituents. The metal complexation chemistry of these new ligands in SC-CO{sub 2} will then be investigated and techniques for their use in actinide extraction from porous solids developed. This report summarizes the work performed during the first 1.3 years of a 3-year program. Because the planned studies of metal complexation and the development of techniques for actinide removal from solids are dependent on the availability of suitable ligands, efforts to date have focused primarily on the synthesis of selected alkyl- or silicon-containing diphosphonic acids. The authors' principal targets have been derivatives in which the silicon-containing groups either serve as the ester function or are attached to the anchor carbon of the diphosphonic acid. Because methylenediphosphonic acid (MDPA) is commercially available and because its esterification with simple alcohols to yield symmetrical diesters is well-established, their initial studies have focused on this ligand and its reactions with silyl alcohols. Success has been achieved in the reaction of MDPA and its ethylene, propylene, and butylene analogs with 3-(trimethylsilyl)-1-propanol. Using a procedure similar to that previously employed for the synthesis of C-8 dialkylmethylenediphosphonic acids, this series of alkylenediphosphonic acids has been esterified in good yield (ca. 60%) to the symmetrically-substituted diesters. Vapor phase osmometric and cryoscopic studies of these compounds in toluene and 1-decanol, respectively, indicate that their aggregation properties closely

  13. Solid Phospholipid Dispersions for Oral Delivery of Poorly Soluble Drugs: Investigation Into Celecoxib Incorporation and Solubility-In Vitro Permeability Enhancement.

    PubMed

    Fong, Sophia Yui Kau; Martins, Susana M; Brandl, Martin; Bauer-Brandl, Annette

    2016-03-01

    Celecoxib (CXB) is a Biopharmaceutical Classification System class II drug in which its oral bioavailability is limited by poor aqueous solubility. Although a range of formulations aiming to increase the solubility of CXB have been developed, it is not completely understood, whether (1) an increase in CXB solubility leads to a subsequent increase in permeability across intestinal barrier and (2) the presence of bile salts affects the solubility and permeability behavior of CXB formulations. By formulating CXB solid phospholipid (PL) dispersions with various PL-to-drug ratios using freeze drying, the present study illustrated that the enhancement of CXB solubility was not proportionally translated into enhanced permeability; both parameters were highly dependent on the PL-to-drug ratios as well as the dispersion media (i.e., the presence of 3-mM sodium taurocholate). This study highlights the importance of evaluating both, solubility and permeability, and the use of biorelevant medium for testing the candidate-enabling performance of liposomal formulations. Mechanisms at molecular level that may explain the effect of PL formulations on the permeability of CXB are also discussed. PMID:26886329

  14. Crosslinked hydrogels—a promising class of insoluble solid molecular dispersion carriers for enhancing the delivery of poorly soluble drugs

    PubMed Central

    Sun, Dajun D.; Lee, Ping I.

    2014-01-01

    Water-insoluble materials containing amorphous solid dispersions (ASD) are an emerging category of drug carriers which can effectively improve dissolution kinetics and kinetic solubility of poorly soluble drugs. ASDs based on water-insoluble crosslinked hydrogels have unique features in contrast to those based on conventional water-soluble and water-insoluble carriers. For example, solid molecular dispersions of poorly soluble drugs in poly(2-hydroxyethyl methacrylate) (PHEMA) can maintain a high level of supersaturation over a prolonged period of time via a feedback-controlled diffusion mechanism thus avoiding the initial surge of supersaturation followed by a sharp decline in drug concentration typically encountered with ASDs based on water-soluble polymers. The creation of both immediate- and controlled-release ASD dosage forms is also achievable with the PHEMA based hydrogels. So far, ASD systems based on glassy PHEMA have been shown to be very effective in retarding precipitation of amorphous drugs in the solid state to achieve a robust physical stability. This review summarizes recent research efforts in investigating the potential of developing crosslinked PHEMA hydrogels as a promising alternative to conventional water-soluble ASD carriers, and a related finding that the rate of supersaturation generation does affect the kinetic solubility profiles implications to hydrogel based ASDs. PMID:26579361

  15. Solid-state actinide acid phosphites from phosphorous acid melts

    NASA Astrophysics Data System (ADS)

    Oh, George N.; Burns, Peter C.

    2014-07-01

    The reaction of UO3 and H3PO3 at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH2(CH3)2)[UO2(HPO2OH)(HPO3)]. This compound crystallizes in space group P21/n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO2OH)4 (An=U, Th) and of the mixed acid phosphite-phosphite U(HPO3)(HPO2OH)2(H2O)·2(H2O). α- and β-An(HPO2OH)4 crystallize in space groups C2/c and P21/n, respectively, and comprise a three-dimensional network of An4+ cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO3)(HPO2OH)2(H2O)2·(H2O) crystallizes in a layered structure in space group Pbca that is composed of An4+ cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized.

  16. Synthesis and solubility of Pb-Ca and P-As hydroxylapatite solid solutions

    NASA Astrophysics Data System (ADS)

    Puzio, Bartosz; Młynarska, Maria; Motyka, Joanna; Oknińska, Joanna; Mandelt, Agnieszka; Chlebowska, Patrycja; Kwaśniak-Kominek, Monika; Manecki, Maciej

    2016-04-01

    The objective of the study are three solid solution series: - HPY hydroxylpyromorphite Pb5(PO4)3OH - HAP hydroxylapatite Ca5(PO4)3OH - HAP hydroxylapatite Ca5(PO4)3OH - JBM johnbaumite Ca5(AsO4)3OH - JBM johnbaumite Ca5(AsO4)3OH - HMI hydroxylmimetite Pb5(AsO4)3OH The phases were synthesized from aqueous solutions at high pH (over 8) at ambient temperature by dropwise mixing of chemical reagents: Pb(NO3)2, Ca(NO3)2.4H2O, (NH4)H2PO4, and Na2AsHO4.7H2O. The products of all syntheses are crystalline, monomineral fine powders (crystal size less than 1 μm). Their chemical composition is close to theoretical. Systematic shift of XRD peaks and FTIR or Raman bands is observed within the solid solution series. Dissolution experiments were run at 5oC, 25oC, 45oC, and 65oC. An aliquot of 0.5g of each phase was dissolved in 250 mL of 0.05M NH4NO3 (pH between 3 and 5) for about 3 months. In all cases dissolution resulted in increase of pH by about 1. The systems were considered in equilibrium when three consecutive samplings (ca. two weeks apart) resulted in similar concentrations (within 3 standard deviations). The dissolution of all phases in question is incongruent. The amount of precipitating secondary phases was too small for identification. The results of HPY - HAP dissolution experiments are inconclusive due to strongly incongruent dissolution. This is partially in contrary to recent report by Zhu et al. (2015). Systematic increase of solubility is observed in HAP - JBM series. Also, the solubility of these phases increases with the increase of temperature. This is more pronounced for HAP than for JBM. Systematic increase of solubility is also observed in HMI - JBM series. This work is partially funded by AGH research grant no 11.11.140.319 and partially by Polish NCN grant No 2014/01/M/ST10/00355. Zhu,Y., Zhu, Z., Zhao, X., Liang, Y., Huang, Y., 2015. Characterization, dissolution, and solubility of lead hydroxypyromorphite Pb5(PO4)3OH at 25-45oC. Journal of Chemistry

  17. Multicomponent complex formation between vinpocetine, cyclodextrins, tartaric acid and water-soluble polymers monitored by NMR and solubility studies.

    PubMed

    Ribeiro, Laura; Carvalho, Rui A; Ferreira, Domingos C; Veiga, Francisco J B

    2005-01-01

    This work deals with multicomponent complex formation of vinpocetine (VP) with beta-cyclodextrin (betaCD), sulfobutyl ether beta-cyclodextrin (SBEbetaCD) and tartaric acid (TA), in the presence or absence of water-soluble polymers, in aqueous solution. Complexation was monitored by phase-solubility and proton nuclear magnetic resonance ((1)H NMR) studies. TA demonstrated a synergistic effect on VP solubility, and in the complexation efficiency of betaCD and SBEbetaCD. Additionally, water-soluble polymers increased even more the complexation efficiency of the CDs that was reflected by a 2.1-2.5 increase on K(C) values for VP-CD-TA-polymer multicomponent complexes. SBEbetaCD was more effective in VP solubilization, as K(C) values of VP-SBEbetaCD-TA multicomponent complexes were notably higher than in corresponding betaCD complexes. The large chemical shift displacements from protons located in the interior of the hydrophobic CD cavities (i.e., H-3 and H-5) coupled with significant chemical shift displacements of VP aromatic protons suggested that this moiety was included in the cavity of both betaCD and SBEbetaCD. Two-dimensional rotating frame nuclear Overhauser effect spectroscopy (ROESY) experiments were carried out in order to obtain information about the multicomponent complex geometry in solution. Inspection of ROESY spectra allowed the establishment of spatial proximities between all aromatic protons of VP and the internal protons of the CDs, confirming that the aromatic moiety of VP is included in CD cavities being deeply inserted in SBEbetaCD multicomponent complexes, since additional interactions with the sulfobutyl side chains were evidenced.

  18. Carbon-based strong solid acid for cornstarch hydrolysis

    SciTech Connect

    Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

    2015-10-15

    Highly sulfonated carbonaceous spheres with diameter of 100–500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO{sub 3}H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO{sub 3}H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst. - Highlights: • Carbon solid acid was successfully prepared by one-step hydrothermal carbonization. • The acrylic acid as monomer was effectively reduce the diameter size of particle. • The solid acid catalyst show good catalytic performance of starch hydrolysis. • The solid acid catalyst is not significantly deteriorated after repeated use.

  19. Experimental determination and prediction of (solid+liquid) phase equilibria for binary mixtures of heavy alkanes and fatty acids

    NASA Astrophysics Data System (ADS)

    Benziane, Mokhtar; Khimeche, Kamel; Dahmani, Abdellah; Nezar, Sawsen; Trache, Djalal

    2012-06-01

    Solid-liquid equilibria for three binary mixtures, n-Eicosane (1) + Lauric acid (2), n-Tetracosane (1) + Stearic acid (2), and n-Octacosane (1) + Palmitic acid (2), were measured using a differential scanning calorimeter. Simple eutectic behaviour was observed for these systems. The experimental results were correlated by means of the modified UNIFAC (Larsen and Gmehling versions), UNIQUAC and ideal models. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.26 to 3.15 K and depend on the particular model used. The best solubility correlation was obtained with the UNIQUAC model.

  20. Removal of acidic or basic α-amino acids in water by poorly water soluble scandium complexes.

    PubMed

    Hayashi, Nobuyuki; Jin, Shigeki; Ujihara, Tomomi

    2012-11-01

    To recognize α-amino acids with highly polar side chains in water, poorly water soluble scandium complexes with both Lewis acidic and basic portions were synthesized as artificial receptors. A suspension of some of these receptor molecules in an α-amino acid solution could remove acidic and basic α-amino acids from the solution. The compound most efficient at preferentially removing basic α-amino acids (arginine, histidine, and lysine) was the receptor with 7,7'-[1,3-phenylenebis(carbonylimino)]bis(2-naphthalenesulfonate) as the ligand. The neutral α-amino acids were barely removed by these receptors. Removal experiments using a mixed amino acid solution generally gave results similar to those obtained using solutions containing a single amino acid. The results demonstrated that the scandium complex receptors were useful for binding acidic and basic α-amino acids. PMID:23050492

  1. Removal of acidic or basic α-amino acids in water by poorly water soluble scandium complexes.

    PubMed

    Hayashi, Nobuyuki; Jin, Shigeki; Ujihara, Tomomi

    2012-11-01

    To recognize α-amino acids with highly polar side chains in water, poorly water soluble scandium complexes with both Lewis acidic and basic portions were synthesized as artificial receptors. A suspension of some of these receptor molecules in an α-amino acid solution could remove acidic and basic α-amino acids from the solution. The compound most efficient at preferentially removing basic α-amino acids (arginine, histidine, and lysine) was the receptor with 7,7'-[1,3-phenylenebis(carbonylimino)]bis(2-naphthalenesulfonate) as the ligand. The neutral α-amino acids were barely removed by these receptors. Removal experiments using a mixed amino acid solution generally gave results similar to those obtained using solutions containing a single amino acid. The results demonstrated that the scandium complex receptors were useful for binding acidic and basic α-amino acids.

  2. Solubility and phase separation of benzocaine and salicylic acid in 1,4-dioxane-water mixtures at several temperatures.

    PubMed

    Peña, M Angeles; Bustamante, Pilar; Escalera, Begoña; Reíllo, Aurora; Bosque-Sendra, Juan Manuel

    2004-11-15

    The solubilities of benzocaine and salicylic acid were determined in water-dioxane mixtures at several temperatures (5-40 degrees C for benzocaine and 10-40 degrees C for salicylic acid). The solubility curves as a function of dioxane ratio showed a maximum at 90% dioxane at all temperatures. Above 25 degrees C, the homogeneous mixture splits into two liquid immiscible phases. For benzocaine, the initial dioxane concentration range at which phase separation takes place increased with temperature (50-60% at 25 degrees C, 50-70% at 30-35 degrees C and 40-70% at 40 degrees C). For salicylic acid, the dioxane concentration required for phase separation (40-60% dioxane) did not change with temperature. Phase separation was not related to solid phase changes (polymorphism or solvates). The phase composition and drug extraction at the drug-rich phase were determined. The apparent enthalpies of the solution process were a nonlinear function of the dioxane ratio for both drugs. The apparent enthalpy of solution of benzocaine was larger than that expected at the upper limit of phase separation (70% dioxane), whereas for salicylic acid the apparent enthalpy of solution decreased abruptly at the region corresponding to phase separation (40-70% dioxane). Both drugs showed a nonlinear pattern of enthalpy-entropy compensation.

  3. Carbon-based strong solid acid for cornstarch hydrolysis

    NASA Astrophysics Data System (ADS)

    Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

    2015-10-01

    Highly sulfonated carbonaceous spheres with diameter of 100-500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO3H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO3H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst.

  4. 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

    NASA Astrophysics Data System (ADS)

    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.

  5. Physicochemical properties of tadalafil solid dispersions - Impact of polymer on the apparent solubility and dissolution rate of tadalafil.

    PubMed

    Wlodarski, K; Sawicki, W; Haber, K; Knapik, J; Wojnarowska, Z; Paluch, M; Lepek, P; Hawelek, L; Tajber, L

    2015-08-01

    To improve solubility of tadalafil (Td), a poorly soluble drug substance (3μg/ml) belonging to the II class of the Biopharmaceutical Classification System, its six different solid dispersions (1:1, w/w) in the following polymers: HPMC, MC, PVP, PVP-VA, Kollicoat IR and Soluplus were successfully produced by freeze-drying. Scanning electron microscopy showed a morphological structure of solid dispersions typical of lyophilisates. Apparent solubility and intrinsic dissolution rate studies revealed the greatest, a 16-fold, increase in drug solubility (50μg/ml) and a significant, 20-fold, dissolution rate enhancement for the Td/PVP-VA solid dispersion in comparison with crystalline Td. However, the longest duration of the supersaturation state in water (27μg/ml) over 24h was observed for the Td solid dispersion in HPMC. The improved dissolution of Td from Td/PVP-VA was confirmed in the standard dissolution test of capsules filled with solid dispersions. Powder X-ray diffraction and thermal analysis showed the amorphous nature of these binary systems and indicated the existence of dispersion at the molecular level and its supersaturated character, respectively. Nevertheless, as evidenced by film casting, the greatest ability to dissolve Td in polymer was determined for PVP-VA. The crystallization tendency of Td dispersed in Kollicoat IR could be explained by the low Tg (113°C) of the solid dispersion and the highest difference in Hansen solubility parameters (6.8MPa(0.5)) between Td and the polymer, although this relationship was not satisfied for the partially crystalline dispersion in PVP. Similarly, no correlation was found between the strength of hydrogen bonds investigated using infrared spectroscopy and the physical stability of solid dispersions or the level of supersaturation in aqueous solution.

  6. Fatty acid and water-soluble polymer-based controlled release drug delivery system.

    PubMed

    Desai, Divyakant; Kothari, Sanjeev; Chen, Wei; Wang, Jennifer; Huang, Ming; Sharma, Laxmikant

    2011-05-01

    Sustained release capsule formulations based on three components, drug, water-soluble polymer, and water-insoluble fatty acid, were developed. Theophylline, acetaminophen, and glipizide, representing a wide spectrum of aqueous solubility, were used as model drugs. Povidone and hydroxypropyl cellulose were selected as water-soluble polymers. Stearic acid and lauric acid were selected as water-insoluble fatty acids. Fatty acid, polymer, and drug mixture was filled into size #0 gelatin capsules and heated for 2 h at 50 °C. The drug particles were trapped into molten fatty acid and released at a controlled rate through pores created by the water-soluble polymer when capsules were exposed to an aqueous dissolution medium. Manipulation of the formulation components enabled release rates of glipizide and theophylline capsules to be similar to commercial Glucotrol XL tablets and Theo-24 capsules, respectively. The capsules also exhibited satisfactory dissolution stability after exposure to 30 °C/60% relative humidity (RH) in open Petri dishes and to 40 °C/75% RH in closed high-density polyethylene bottles. A computational fluid dynamic-based model was developed to quantitatively describe the drug transport in the capsule matrix and the drug release process. The simulation results showed a diffusion-controlled release mechanism from these capsules.

  7. Molecular simulation of aqueous electrolyte solubility. 3. Alkali-halide salts and their mixtures in water and in hydrochloric acid.

    PubMed

    Moučka, Filip; Lísal, Martin; Smith, William R

    2012-05-10

    We extend the osmotic ensemble Monte Carlo (OEMC) molecular simulation method (Moučka et al. J. Phys Chem. B 2011, 115, 7849-7861) for directly calculating the aqueous solubility of electrolytes and for calculating their chemical potentials as functions of concentration to cases involving electrolyte hydrates and mixed electrolytes, including invariant points involving simultaneous precipitation of several solutes. The method utilizes a particular semigrand canonical ensemble, which performs simulations of the solution at a fixed number of solvent molecules, pressure, temperature, and specified overall electrolyte chemical potential. It avoids calculations for the solid phase, incorporating available solid chemical potential data from thermochemical tables, which are based on well-defined reference states, or from other sources. We apply the method to a range of alkali halides in water and to selected examples involving LiCl monohydrate, mixed electrolyte solutions involving water and hydrochloric acid, and invariant points in these solvents. The method uses several existing force-field models from the literature, and the results are compared with experiment. The calculated results agree qualitatively well with the experimental trends and are of reasonable accuracy. The accuracy of the calculated solubility is highly dependent on the solid chemical potential value and also on the force-field model used. Our results indicate that pairwise additive effective force-field models developed for the solution phase are unlikely to also be good models for the corresponding crystalline solid. We find that, in our OEMC simulations, each ionic force-field model is characterized by a limiting value of the total solution chemical potential and a corresponding aqueous concentration. For higher values of the imposed chemical potential, the solid phase in the simulation grows in size without limit.

  8. Solid-state actinide acid phosphites from phosphorous acid melts

    SciTech Connect

    Oh, George N.; Burns, Peter C.

    2014-07-01

    The reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})]. This compound crystallizes in space group P2{sub 1}/n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO{sub 2}OH){sub 4} (An=U, Th) and of the mixed acid phosphite–phosphite U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O)·2(H{sub 2}O). α- and β-An(HPO{sub 2}OH){sub 4} crystallize in space groups C2/c and P2{sub 1}/n, respectively, and comprise a three-dimensional network of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O){sub 2}·(H{sub 2}O) crystallizes in a layered structure in space group Pbca that is composed of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized. - Graphical abstract: Reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with DMF produces crystals of (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})] with a layered structure. Reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup and further solution-state reactions result in the crystallization of the actinide acid phosphites An(HPO{sub 2}OH){sub 4} (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite

  9. Immobilization of soluble protein complexes in MAS solid-state NMR: Sedimentation versus viscosity.

    PubMed

    Sarkar, Riddhiman; Mainz, Andi; Busi, Baptiste; Barbet-Massin, Emeline; Kranz, Maximilian; Hofmann, Thomas; Reif, Bernd

    2016-01-01

    In recent years, MAS solid-state NMR has emerged as a technique for the investigation of soluble protein complexes. It was found that high molecular weight complexes do not need to be crystallized in order to obtain an immobilized sample for solid-state NMR investigations. Sedimentation induced by sample rotation impairs rotational diffusion of proteins and enables efficient dipolar coupling based cross polarization transfers. In addition, viscosity contributes to the immobilization of the molecules in the sample. Natural Deep Eutectic Solvents (NADES) have very high viscosities, and can replace water in living organisms. We observe a considerable amount of cross polarization transfers for NADES solvents, even though their molecular weight is too low to yield significant sedimentation. We discuss how viscosity and sedimentation both affect the quality of the obtained experimental spectra. The FROSTY/sedNMR approach holds the potential to study large protein complexes, which are otherwise not amenable for a structural characterization using NMR. We show that using this method, backbone assignments of the symmetric proteasome activator complex (1.1MDa), and high quality correlation spectra of non-symmetric protein complexes such as the prokaryotic ribosome 50S large subunit binding to trigger factor (1.4MDa) are obtained. PMID:27017576

  10. The biological significance of soluble interleukin-2 receptors in solid tumors.

    PubMed

    Lissoni, P; Barni, S; Rovelli, F; Viviani, S; Maestroni, G J; Conti, A; Tancini, G

    1990-01-01

    In an attempt to further understand the biological significance of soluble IL-2 receptors (sIL-2R) in solid tumors, we have evaluated 160 cancer patients (breast: 40; lung: 66; colon: 18; stomach: 22; uterine cervix: 14) and 58 healthy subjects, as controls. Serum mean levels of sIL-2R, measured with an enzyme immunoassay, were significantly higher in cancer patients than in controls. Metastatic cancer patients showed significantly higher values than the non-metastatic ones; this difference was significant in all tumor histotypes, except small cell lung carcinoma. Moreover, in 15 patients in whom sIL-2R were evaluated either before or after radical surgery, a significant surgery-induced increase in sIL-R mean values was seen. Finally, the chemotherapy-induced rise in sIL-2R appeared to be associated with a lack of clinical response. These results seem to suggest that sIL-2R may be a marker of host biological response in patients with solid tumors, the significance of which needs further investigation.

  11. Immobilization of soluble protein complexes in MAS solid-state NMR: Sedimentation versus viscosity.

    PubMed

    Sarkar, Riddhiman; Mainz, Andi; Busi, Baptiste; Barbet-Massin, Emeline; Kranz, Maximilian; Hofmann, Thomas; Reif, Bernd

    2016-01-01

    In recent years, MAS solid-state NMR has emerged as a technique for the investigation of soluble protein complexes. It was found that high molecular weight complexes do not need to be crystallized in order to obtain an immobilized sample for solid-state NMR investigations. Sedimentation induced by sample rotation impairs rotational diffusion of proteins and enables efficient dipolar coupling based cross polarization transfers. In addition, viscosity contributes to the immobilization of the molecules in the sample. Natural Deep Eutectic Solvents (NADES) have very high viscosities, and can replace water in living organisms. We observe a considerable amount of cross polarization transfers for NADES solvents, even though their molecular weight is too low to yield significant sedimentation. We discuss how viscosity and sedimentation both affect the quality of the obtained experimental spectra. The FROSTY/sedNMR approach holds the potential to study large protein complexes, which are otherwise not amenable for a structural characterization using NMR. We show that using this method, backbone assignments of the symmetric proteasome activator complex (1.1MDa), and high quality correlation spectra of non-symmetric protein complexes such as the prokaryotic ribosome 50S large subunit binding to trigger factor (1.4MDa) are obtained.

  12. Solubility of HOBr in Acidic Solution and Implications for Liberation of Halogens Via Aerosol Processing

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Michelsen, R. R.; Rammer, T. A.; Ashbourn, S. F. M.

    2004-01-01

    Halogen species are known to catalytically destroy ozone in several regions of the atmosphere. In addition to direct catalytic losses, bromine compounds can indirectly enhance ozone loss through coupling to other radical families. Hypobromous acid (HOBr) is a key species in the linkage of BrOx to ClOx and HOx. The aqueous- phase coupling reaction HOBr + HCI (right arrow) BrCl + H2O may provide a pathway for chlorine activation on sulfate aerosols at temperatures warmer than those required for polar stratospheric cloud formation. We have measured t h e solubility of HOBr in 45 - 70 wt% sulfuric acid solutions. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, H* = 10(exp 4) - 10(exp 7) mol dm(exp -3) atm(exp -1). The expected inverse dependence of H* on temperature was observed, but only a weak dependence on acidity was found. The solubility of HOBr is comparable to that of HBr, indicating that equilibrium concentrations of HOBr could equal or exceed those of HBr in upper tropospheric and lower stratospheric aerosols. Despite the high solubility of HOBr, aerosol volumes are not large enough to sequester a significant fraction of inorganic bromine from the gas phase. Our measurements of HOBr uptake in aqueous sulfuric acid in the presence of other brominated gases show the evolution of gaseous products including Br2O and Br2.

  13. Solubility calculations of branched and linear amino acids using lattice cluster theory

    NASA Astrophysics Data System (ADS)

    Fischlschweiger, Michael; Enders, Sabine; Zeiner, Tim

    2014-09-01

    In this work, the activity coefficients and the solubility of amino acids in water were calculated using the lattice cluster theory (LCT) combined with the extended chemical association lattice model allowing self-association as well as cross-association. This permits the study of the influence of the amino acids structure on the thermodynamic properties for the first time. By the used model, the activity coefficient and solubilities of the investigated fourteen amino acids (glycine, alanine, γ-aminobutyric acid, dl-valine, dl-threonine, dl-methionine, l-leucine, l-glutamic acid, l-proline, hydroxyproline, histidine, l-arginine, α-amino valeric acid) could be described in good accordance with experimental data. In the case of different α-amino acids, but different hydrocarbon chains, the same interaction energy parameter can be used within the LCT. All studied amino acids could be modelled using the same parameter for the description of the amino acid association properties. The formed cross-associates contain more amino acids than expressed by the overall mole fraction of the solution. Moreover, the composition of the cross-associates depends on temperature, where the amount of amino acids increases with increasing temperature.

  14. Foliar reflective film and water deficit increase anthocyanin to soluble solids ratio during berry ripening in Merlot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated temperature can decrease the ratio of anthocyanins to soluble solids in red-skinned berries and warming trends in grape production regions have raised concern about color to alcohol balance in wines produced from fruit with altered ratios. In this study, we tested the effectiveness of a fol...

  15. Mefenamic acid taste-masked oral disintegrating tablets with enhanced solubility via molecular interaction produced by hot melt extrusion technology

    PubMed Central

    Alshehri, Sultan M.; Park, Jun-Bom; Alsulays, Bader B.; Tiwari, Roshan V.; Almutairy, Bjad; Alshetaili, Abdullah S.; Morott, Joseph; Shah, Sejal; Kulkarni, Vijay; Majumdar, Soumyajit; Martin, Scott T.; Mishra, Sanjay; Wang, Lijia; Repka, Michael A.

    2015-01-01

    The objective of this study was to enhance the solubility as well as to mask the intensely bitter taste of the poorly soluble drug, Mefenamic acid (MA). The taste masking and solubility of the drug was improved by using Eudragit® E PO in different ratios via hot melt extrusion (HME), solid dispersion technology. Differential scanning calorimetry (DSC) studies demonstrated that MA and E PO were completely miscible up to 40% drug loads. Powder X-ray diffraction analysis indicated that MA was converted to its amorphous phase in all of the formulations. Additionally, FT-IR analysis indicated hydrogen bonding between the drug and the carrier up to 25% of drug loading. SEM images indicated aggregation of MA at over 30% of drug loading. Based on the FT-IR, SEM and dissolution results for the extrudates, two optimized formulations (20% and 25% drug loads) were selected to formulate the orally disintegrating tablets (ODTs). ODTs were successfully prepared with excellent friability and rapid disintegration time in addition to having the desired taste-masking effect. All of the extruded formulations and the ODTs were found to be physically and chemically stable over a period of 6 months at 40°C/75% RH and 12 months at 25°C/60% RH, respectively. PMID:25914727

  16. Acid-soluble magnesia cement; New applications in completion and workover operations

    SciTech Connect

    Sweatman, R.E.; Scoggins, W.C. )

    1990-11-01

    Acid-soluble magnesia cement (MC) was used in production zones to plug perforations temporarily to reduce brine losses during completion and workover operations. This has resulted in substantial savings for operators. The cement has also been used to reduce potential formation damage. This paper describes some of the characteristics of the cement, field applications, and results.

  17. Phenolic acids and antioxidant capacity of distillers dried grains with solubles (DDGS) as compared with corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three sets of ground corn and the corresponding distillers dried grains with solubles (DDGS) were collected from three commercial plants and analyzed for individual phenolic acids by high performance liquid chromatography coupled with diode array and/or mass spectrometry and for antioxidant capacity...

  18. Phenolic acids and antioxidant activity of distillers dried grains with solubles (DDGS) as compared with corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sample sets of ground corn and the corresponding distillers dried grains with solubles (DDGS) were collected from three commercial plants in Iowa. Phenolic acids were analyzed by high performance liquid chromatography coupled with diode array and/or mass spectrometry. The antioxidant activity was ...

  19. Determination of water-soluble forms of oxalic and formic acids in soils by ion chromatography

    NASA Astrophysics Data System (ADS)

    Karicheva, E.; Guseva, N.; Kambalina, M.

    2016-03-01

    Carboxylic acids (CA) play an important role in the chemical composition origin of soils and migration of elements. The content of these acids and their salts is one of the important characteristics for agrochemical, ecological, ameliorative and hygienic assessment of soils. The aim of the article is to determine water-soluble forms of same carboxylic acids — (oxalic and formic acids) in soils by ion chromatography with gradient elution. For the separation and determination of water-soluble carboxylic acids we used reagent-free gradient elution ion-exchange chromatography ICS-2000 (Dionex, USA), the model solutions of oxalate and formate ions, and leachates from soils of the Kola Peninsula. The optimal gradient program was established for separation and detection of oxalate and formate ions in water solutions by ion chromatography. A stability indicating method was developed for the simultaneous determination of water-soluble organic acids in soils. The method has shown high detection limits such as 0.03 mg/L for oxalate ion and 0.02 mg/L for formate ion. High signal reproducibility was achieved in wide range of intensities which correspond to the following ion concentrations: from 0.04 mg/g to 10 mg/L (formate), from 0.1 mg/g to 25 mg/L (oxalate). The concentration of formate and oxalate ions in soil samples is from 0.04 to 0.9 mg/L and 0.45 to 17 mg/L respectively.

  20. Influence of manufacturing factors on physical stability and solubility of solid dispersions containing a low glass transition temperature drug.

    PubMed

    Sakurai, Atsushi; Sako, Kazuhiro; Maitani, Yoshie

    2012-01-01

    In this study, we investigated the effect of manufacturing factors such as particle size, water content and manufacturing method on the physical stability and solubility of solid dispersion formulations of a low-glass-transition-temperature (T(g)) drug. Solid dispersions were prepared from polyvinylpyrrolidone (PVP) and hydroxypropylmethylcellulose (HPMC) by hot melt extrusion or spray drying. Water content of solid dispersions prepared by hot melt extrusion determined by dynamic moisture sorption measurement was increased drastically with relative humidity below a certain level of particle size. The blends with a lower water content (0.8%) prepared by hot melt extrusion during storage were more stable than those with a higher water content (3.5%) prepared by spray drying, which caused rapid recrystallization. Physical stability in the hot melt blends may be attributed to reduced molecular mobility due to a higher T(g). Dissolution study revealed that solid dispersions prepared by hot melt extrusion with the smallest particle size showed decreased solubility, attributed to reduced wetting properties (surface energy), which is not predictable by the Noyes-Whitney equation. Taken together, these results indicate that the control of particle size concerned in water content or wetting properties is critical to ensuring the physical stability or enhancing solubility of low-T(g) drugs. Further, hot melt extrusion, which can reduce water content, is a suitable manufacturing method for solid dispersions of low-T(g) drugs. PMID:23124559

  1. Influence of manufacturing factors on physical stability and solubility of solid dispersions containing a low glass transition temperature drug.

    PubMed

    Sakurai, Atsushi; Sako, Kazuhiro; Maitani, Yoshie

    2012-01-01

    In this study, we investigated the effect of manufacturing factors such as particle size, water content and manufacturing method on the physical stability and solubility of solid dispersion formulations of a low-glass-transition-temperature (T(g)) drug. Solid dispersions were prepared from polyvinylpyrrolidone (PVP) and hydroxypropylmethylcellulose (HPMC) by hot melt extrusion or spray drying. Water content of solid dispersions prepared by hot melt extrusion determined by dynamic moisture sorption measurement was increased drastically with relative humidity below a certain level of particle size. The blends with a lower water content (0.8%) prepared by hot melt extrusion during storage were more stable than those with a higher water content (3.5%) prepared by spray drying, which caused rapid recrystallization. Physical stability in the hot melt blends may be attributed to reduced molecular mobility due to a higher T(g). Dissolution study revealed that solid dispersions prepared by hot melt extrusion with the smallest particle size showed decreased solubility, attributed to reduced wetting properties (surface energy), which is not predictable by the Noyes-Whitney equation. Taken together, these results indicate that the control of particle size concerned in water content or wetting properties is critical to ensuring the physical stability or enhancing solubility of low-T(g) drugs. Further, hot melt extrusion, which can reduce water content, is a suitable manufacturing method for solid dispersions of low-T(g) drugs.

  2. Influence of the physiological stage and the content of soluble solids on the anthocyanin extractability of Vitis vinifera L. cv. Tempranillo grapes.

    PubMed

    Hernández-Hierro, José Miguel; Quijada-Morín, Natalia; Rivas-Gonzalo, Julián C; Escribano-Bailón, M Teresa

    2012-06-30

    The influence and the extent of the anthocyanin extractability from grape skins at different physiological stages and different soluble solids contents within each stage were investigated. For this purpose three different physiological stages (pre-harvest, harvest and over-ripening) and three soluble solids contents (22, 24 and 26°Brix) within each stage were taken into account using Vitis vinifera L. cv. Tempranillo. This study revealed the influence of physiological stages and soluble solids contents on the amounts of anthocyanins. The most important factor was the physiological stage although the soluble solid contents effect was also relevant, especially for anthocyanins monoglucosides. The highest contents in anthocyanins were found at pre-harvest, following by harvest and finally at over-ripening. Within each physiological stage, the relative abundance of acylated derivatives was influenced by the soluble solids contents. The percentages of acylated anthocyanins tend to decrease as the soluble solids contents. Differences in the anthocyanin extractabilities were highly influenced by the physiological stages and in a lesser extent by the soluble solids contents. The lowest extraction percentages were obtained in pre-harvest samples whatever soluble solids contents. Over-ripening samples present the lowest contents of anthocyanins but these compounds are easily released from tissues to the hydroalcoholic solution providing the highest extraction percentages. Generally, non-acylated anthocyanins were better extracted than the acylated anthocyanins.

  3. Amino acids as co-amorphous stabilizers for poorly water soluble drugs--Part 1: preparation, stability and dissolution enhancement.

    PubMed

    Löbmann, Korbinian; Grohganz, Holger; Laitinen, Riikka; Strachan, Clare; Rades, Thomas

    2013-11-01

    Poor aqueous solubility of an active pharmaceutical ingredient (API) is one of the most pressing problems in pharmaceutical research and development because up to 90% of new API candidates under development are poorly water soluble. These drugs usually have a low and variable oral bioavailability, and therefore an unsatisfactory therapeutic effect. One of the most promising approaches to increase dissolution rate and solubility of these drugs is the conversion of a crystalline form of the drug into its respective amorphous form, usually by incorporation into hydrophilic polymers, forming glass solutions. However, this strategy only led to a small number of marketed products usually because of inadequate physical stability of the drug (crystallization). In this study, we investigated a fundamentally different approach to stabilize the amorphous form of drugs, namely the use of amino acids as small molecular weight excipients that form specific molecular interactions with the drug resulting in co-amorphous forms. The two poorly water soluble drugs carbamazepine and indomethacin were combined with amino acids from the binding sites of the biological receptors of these drugs. Mixtures of drug and the amino acids arginine, phenylalanine, tryptophan and tyrosine were prepared by vibrational ball milling. Solid-state characterization with X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) revealed that the various blends could be prepared as homogeneous, single phase co-amorphous formulations indicated by the appearance of an amorphous halo in the XRPD diffractograms and a single glass transition temperature (Tg) in the DSC measurements. In addition, the Tgs of the co-amorphous mixtures were significantly increased over those of the individual drugs. The drugs remained chemically stable during the milling process and the co-amorphous formulations were generally physically stable over at least 6 months at 40 °C under dry conditions. The

  4. Field and Laboratory Studies of Reactions between Atmospheric Water Soluble Organic Acids and Inorganic Particles

    SciTech Connect

    Wang, Bingbing; Kelly, Stephen T.; Sellon, Rachel E.; Shilling, John E.; Tivanski, Alexei V.; Moffet, Ryan C.; Gilles, Mary K.; Laskin, Alexander

    2013-06-25

    Atmospheric inorganic particles undergo complex heterogeneous reactions that change their physicochemical properties. Depletion of chloride in sea salt particles was reported in previous field studies and was attributed to the acid displacement of chlorides with inorganic acids, such as nitric and sulfuric acids [1-2]. Recently, we showed that NaCl can react with water soluble organic acids (WSOA) and release gaseous hydrochloric acid (HCl) resulting in formation of organic salts [3]. A similar mechanism is also applicable to mixed WSOA/nitrate particles where multi-phase reactions are driven by the volatility of nitric acid. Furthermore, secondary organic material, which is a complex mixture of carboxylic acids, exhibits the same reactivity towards chlorides and nitrates. Here, we present a systematic study of reactions between atmospheric relevant WSOA, SOM, and inorganic salts including NaCl, NaNO3, and Ca(NO3)2 using complementary micro-spectroscopy analysis.

  5. Neural network and principal component regression in non-destructive soluble solids content assessment: a comparison*

    PubMed Central

    Chia, Kim-seng; Abdul Rahim, Herlina; Abdul Rahim, Ruzairi

    2012-01-01

    Visible and near infrared spectroscopy is a non-destructive, green, and rapid technology that can be utilized to estimate the components of interest without conditioning it, as compared with classical analytical methods. The objective of this paper is to compare the performance of artificial neural network (ANN) (a nonlinear model) and principal component regression (PCR) (a linear model) based on visible and shortwave near infrared (VIS-SWNIR) (400–1000 nm) spectra in the non-destructive soluble solids content measurement of an apple. First, we used multiplicative scattering correction to pre-process the spectral data. Second, PCR was applied to estimate the optimal number of input variables. Third, the input variables with an optimal amount were used as the inputs of both multiple linear regression and ANN models. The initial weights and the number of hidden neurons were adjusted to optimize the performance of ANN. Findings suggest that the predictive performance of ANN with two hidden neurons outperforms that of PCR. PMID:22302428

  6. Aqueous extraction kinetics of soluble solids, phenolics and flavonoids from sage (Salvia fruticosa Miller) leaves.

    PubMed

    Torun, Mehmet; Dincer, Cuneyt; Topuz, Ayhan; Sahin-Nadeem, Hilal; Ozdemir, Feramuz

    2015-05-01

    In the present study, aqueous extraction kinetics of total soluble solids (TSS), total phenolic content (TPC) and total flavonoid content (TFC) from Salvia fruticosa leaves were investigated throughout 150 min. of extraction period against temperature (60-80 °C), particle size (2-8 mm) and loading percentage (1-4 %). The extract yielded 25 g/100 g TSS which contained 30 g/100 g TPC and 25 g/100 g TFC. The extraction data in time course fit with reversible first order kinetic model. All tested variables showed significant effect on the estimated kinetic parameters except equilibrium concentration. Increasing the extraction temperature resulted high extraction rate constants and equilibrium concentrations of the tested variables notably above 70 °C. By using the Arrhenius relationship, activation energy of the TSS, TPC and TFC were determined as 46.11 ± 5.61, 36.80 ± 3.12 and 33.52 ± 2.23 kj/mol, respectively. By decreasing the particle size, the extraction rate constants and diffusion coefficients exponentially increased whereas equilibrium concentrations did not change significantly. The equilibrium concentrations of the tested parameters showed linear behavior with increasing the loading percentage of the sage, however; the change in extraction rates did not show linear behavior due to submerging effect of 4 % loading.

  7. Nondestructive evaluation of soluble solid content in strawberry by near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Guo, Zhiming; Huang, Wenqian; Chen, Liping; Wang, Xiu; Peng, Yankun

    This paper indicates the feasibility to use near infrared (NIR) spectroscopy combined with synergy interval partial least squares (siPLS) algorithms as a rapid nondestructive method to estimate the soluble solid content (SSC) in strawberry. Spectral preprocessing methods were optimized selected by cross-validation in the model calibration. Partial least squares (PLS) algorithm was conducted on the calibration of regression model. The performance of the final model was back-evaluated according to root mean square error of calibration (RMSEC) and correlation coefficient (R2 c) in calibration set, and tested by mean square error of prediction (RMSEP) and correlation coefficient (R2 p) in prediction set. The optimal siPLS model was obtained with after first derivation spectra preprocessing. The measurement results of best model were achieved as follow: RMSEC = 0.2259, R2 c = 0.9590 in the calibration set; and RMSEP = 0.2892, R2 p = 0.9390 in the prediction set. This work demonstrated that NIR spectroscopy and siPLS with efficient spectral preprocessing is a useful tool for nondestructively evaluation SSC in strawberry.

  8. [Prediction the Soluble Solid Content in Sugarcanes by Using Near Infrared Hyperspectral Imaging System].

    PubMed

    Gao, Jun-feng; Zhang, Chu; Xie, Chuan-qi; Zhu, Feng-le; Guo, Zhen-hao; He, Yong

    2015-08-01

    In order to explore the feasibility of prediction soluble solid contents (SSC) in sugarcane stalks by using near infrared hyperspectral imaging techniques, two hundred and forty sugarcane stalks which come from three different varieties were studied. After obtaining the raw hyperspectral images of sugarcane stalks, the spectral information and textural features were discussed respectively. The prediction models were established by using partial least squares regression (PLSR), principal components regression (PCR) and least squares support vector machines (LS-SVM) algorithms. Besides, three different selected wavelengths algorithms such as successive projection (SPA) algorithms, intervals partial least squares (iPLS) algorithms and uninformation variables elimination (UVE) algorithm were analyzed after building partial least squares regression model. The results indicate that partial least squares regression model based on spectral features can be an steady model to predict SSC and the correlation coefficient (R2) of calibration sets and prediction sets are 0.879, 0.843. The root mean square errors of calibration sets and prediction sets are 0.644, 0.742 respectively. The obtained 105 wavelengths which were selected by UVE algorithm are effective spectral features. The R2 results of calibration sets and prediction sets of its PLSR model are 0.860, 0.813. The root mean square errors of calibration sets and prediction sets are 0.693, 0.810 respectively PMID:26672284

  9. Interactions in the solid state. II: Interaction of sodium bicarbonate with substituted benzoic acids in the presence of moisture.

    PubMed

    Wright, J L; Carstensen, J T

    1986-06-01

    The interaction of an organic acid with sodium bicarbonate in water produces an effervescent reaction. The reaction products are carbon dioxide, water, and the sodium salt of the acid. The kinetic rate-determining step for this reaction is the dehydration of carbonic acid. The solid-solid interaction with known amounts of moisture was followed by quantitatively determining carbon dioxide evolution as a function of time. The aqueous solubilities, diffusion coefficients, dissociation constants, and solid-solid interaction rates of six different substituted benzoic acids were determined. Using a model based on diffusion of the organic acid through the aqueous layer coupled with chemical reaction, predicted rates and levels of carbon dioxide production were compared with experimental results. Included in the model were the effects of the reaction products on the solution properties of the reactants. It was found that high concentrations of substituted sodium benzoate were generated very quickly and affected the solubility of the reactants, diffusion coefficient of the acid, and the carbonic acid dehydration rate constant. Moisture content was found to have a profound influence on the interaction rate. Water provides a medium for diffusion of the reacting species as well as the reaction solvent. PMID:3016234

  10. Interactions in the solid state. II: Interaction of sodium bicarbonate with substituted benzoic acids in the presence of moisture

    SciTech Connect

    Wright, J.L.; Carstensen, J.T.

    1986-06-01

    The interaction of an organic acid with sodium bicarbonate in water produces an effervescent reaction. The reaction products are carbon dioxide, water, and the sodium salt of the acid. The kinetic rate-determining step for this reaction is the dehydration of carbonic acid. The solid-solid interaction with known amounts of moisture was followed by quantitatively determining carbon dioxide evolution as a function of time. The aqueous solubilities, diffusion coefficients, dissociation constants, and solid-solid interaction rates of six different substituted benzoic acids were determined. Using a model based on diffusion of the organic acid through the aqueous layer coupled with chemical reaction, predicted rates and levels of carbon dioxide production were compared with experimental results. Included in the model were the effects of the reaction products on the solution properties of the reactants. It was found that high concentrations of substituted sodium benzoate were generated very quickly and affected the solubility of the reactants, diffusion coefficient of the acid, and the carbonic acid dehydration rate constant. Moisture content was found to have a profound influence on the interaction rate. Water provides a medium for diffusion of the reacting species as well as the reaction solvent.

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

    USGS Publications Warehouse

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

    1992-01-01

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

  12. Acidic Properties and Structure-Activity Correlations of Solid Acid Catalysts Revealed by Solid-State NMR Spectroscopy.

    PubMed

    Zheng, Anmin; Li, Shenhui; Liu, Shang-Bin; Deng, Feng

    2016-04-19

    Solid acid materials with tunable structural and acidic properties are promising heterogeneous catalysts for manipulating and/or emulating the activity and selectivity of industrially important catalytic reactions. On the other hand, the performances of acid-catalyzed reactions are mostly dictated by the acidic features, namely, type (Brønsted vs Lewis acidity), amount, strength, and local environment of acid sites. The latter is relevant to their location (intra- vs extracrystalline), and possible confinement and Brønsted-Lewis acid synergy effects that may strongly affect the host-guest interactions, reaction mechanism, and shape selectivity of the catalytic system. This account aims to highlight some important applications of state-of-the-art solid-state NMR (SSNMR) techniques for exploring the structural and acidic properties of solid acid catalysts as well as their catalytic performances and relevant reaction pathway invoked. In addition, density functional theory (DFT) calculations may be exploited in conjunction with experimental SSNMR studies to verify the structure-activity correlations of the catalytic system at a microscopic scale. We describe in this Account the developments and applications of advanced ex situ and/or in situ SSNMR techniques, such as two-dimensional (2D) double-quantum magic-angle spinning (DQ MAS) homonuclear correlation spectroscopy for structural investigation of solid acids as well as study of their acidic properties. Moreover, the energies and electronic structures of the catalysts and detailed catalytic reaction processes, including the identification of reaction species, elucidation of reaction mechanism, and verification of structure-activity correlations, made available by DFT theoretical calculations were also discussed. Relevant discussions will focus primarily on results obtained from our laboratories in the past decade, including (i) quantitative and qualitative acidity characterization utilizing assorted probe molecules

  13. Solubility of methanol in low-temperature aqueous sulfuric acid and implications for atmospheric particle composition

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    Using traditional Knudsen cell techniques, we find well-behaved Henry's law uptake of methanol in aqueous 45 - 70 wt% H2SO4 solutions at temperatures between 197 and 231 K. Solubility of methanol increases with decreasing temperature and increasing acidity, with an effective Henry's law coefficient ranging from 10(exp 5) - 10(exp 8) M/atm. Equilibrium uptake of methanol into sulfuric acid aerosol particles in the upper troposphere and lower stratosphere will not appreciably alter gas-phase concentrations of methanol. The observed room temperature reaction between methanol and sulfuric acid is too slow to provide a sink for gaseous methanol at the temperatures of the upper troposphere and lower stratosphere. It is also too slow to produce sufficient quantities of soluble reaction products to explain the large amount of unidentified organic material seen in particles of the upper troposphere.

  14. Interaction between Tea Polyphenols and Bile Acid Inhibits Micellar Cholesterol Solubility.

    PubMed

    Ogawa, Kazuki; Hirose, Sayumi; Nagaoka, Satoshi; Yanase, Emiko

    2016-01-13

    The molecular mechanism by which tea polyphenols decrease the micellar solubility of cholesterol is not completely clear. To clarify this mechanism, this study investigated the interaction between tea polyphenols (catechins and oolongtheanins) and cholesterol micelles. A nuclear magnetic resonance (NMR) study was performed on a micellar solution containing taurocholic acid and epigallocatechin gallate (EGCg), and high-performance liquid chromatography (HPLC) analysis was carried out on the precipitate and the supernatant that formed when EGCg was added to a cholesterol-micelle solution. The data indicated a regiospecific interaction of EGCg with taurocholic acid. Therefore, the ability of EGCg to lower the solubility of phosphatidylcholine (PC) and cholesterol in micellar solutions can be attributed to their elimination from the micelles due to interaction between taurocholic acids and EGCg.

  15. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    NASA Astrophysics Data System (ADS)

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad

    2015-09-01

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD).

  16. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    SciTech Connect

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad

    2015-09-25

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD)

  17. Interaction between Tea Polyphenols and Bile Acid Inhibits Micellar Cholesterol Solubility.

    PubMed

    Ogawa, Kazuki; Hirose, Sayumi; Nagaoka, Satoshi; Yanase, Emiko

    2016-01-13

    The molecular mechanism by which tea polyphenols decrease the micellar solubility of cholesterol is not completely clear. To clarify this mechanism, this study investigated the interaction between tea polyphenols (catechins and oolongtheanins) and cholesterol micelles. A nuclear magnetic resonance (NMR) study was performed on a micellar solution containing taurocholic acid and epigallocatechin gallate (EGCg), and high-performance liquid chromatography (HPLC) analysis was carried out on the precipitate and the supernatant that formed when EGCg was added to a cholesterol-micelle solution. The data indicated a regiospecific interaction of EGCg with taurocholic acid. Therefore, the ability of EGCg to lower the solubility of phosphatidylcholine (PC) and cholesterol in micellar solutions can be attributed to their elimination from the micelles due to interaction between taurocholic acids and EGCg. PMID:26651358

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

    SciTech Connect

    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.

  19. Solid/liquid phase diagram of the ammonium sulfate/succinic acid/water system.

    PubMed

    Pearson, Christian S; Beyer, Keith D

    2015-05-14

    We have studied the low-temperature phase diagram and water activities of the ammonium sulfate/succinic acid/water system using differential scanning calorimetry and infrared spectroscopy of thin films. Using the results from our experiments, we have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/succinic acid phase boundary as well as the ternary eutectic composition and temperature. We also compared our results to the predictions of the extended AIM aerosol thermodynamics model (E-AIM) and found good agreement for the ice melting points in the ice primary phase field of this system; however, differences were found with respect to succinic acid solubility temperatures. We also compared the results of this study with those of previous studies that we have published on ammonium sulfate/dicarboxylic acid/water systems. PMID:25431860

  20. Design, optimization and evaluation of glipizide solid self-nanoemulsifying drug delivery for enhanced solubility and dissolution.

    PubMed

    Dash, Rajendra Narayan; Mohammed, Habibuddin; Humaira, Touseef; Ramesh, Devi

    2015-10-01

    A solid self-nanoemulsifying drug-delivery system (solid SNEDDS) has been explored to improve the solubility and dissolution profile of glipizide. SNEDDS preconcentrate was systematically optimized using a circumscribed central composite design by varying Captex 355 (Oil), Solutol HS15 (Surfactant) and Imwitor 988 (Co-surfactant). The optimized SNEDDS preconcentrate consisted of Captex 355 (30% w/w), Solutol HS15 (45% w/w) and Imwitor 988 (25% w/w). The saturation solubility (SS) of glipizide in optimized SNEDDS preconcentrate was found to be 45.12 ± 1.36 mg/ml, indicating an improvement (1367 times) of glipizide solubility as compared to its aqueous solubility (0.033 ± 0.0021 mg/ml). At 90% SS, glipizide was loaded to the optimized SNEDDS. In-vitro dilution of liquid SNEDDS resulted in a nanoemulsion with a mean droplet size of 29.4 nm. TEM studies of diluted liquid SNEDDS confirmed the uniform shape and size of the globules. The liquid SNEDDS was adsorbed onto calcium carbonate and talc to form solid SNEDDS. PXRD, DSC, and SEM results indicated that, the presence of glipizide as an amorphous and as a molecular dispersion state within solid SNEDDS. Glipizide dissolution improved significantly (p < 0.001) from the solid SNEDDS (∼100% in 15 min) as compared to the pure drug (18.37%) and commercial product (65.82) respectively. PMID:26594119

  1. Design, optimization and evaluation of glipizide solid self-nanoemulsifying drug delivery for enhanced solubility and dissolution

    PubMed Central

    Dash, Rajendra Narayan; Mohammed, Habibuddin; Humaira, Touseef; Ramesh, Devi

    2015-01-01

    A solid self-nanoemulsifying drug-delivery system (solid SNEDDS) has been explored to improve the solubility and dissolution profile of glipizide. SNEDDS preconcentrate was systematically optimized using a circumscribed central composite design by varying Captex 355 (Oil), Solutol HS15 (Surfactant) and Imwitor 988 (Co-surfactant). The optimized SNEDDS preconcentrate consisted of Captex 355 (30% w/w), Solutol HS15 (45% w/w) and Imwitor 988 (25% w/w). The saturation solubility (SS) of glipizide in optimized SNEDDS preconcentrate was found to be 45.12 ± 1.36 mg/ml, indicating an improvement (1367 times) of glipizide solubility as compared to its aqueous solubility (0.033 ± 0.0021 mg/ml). At 90% SS, glipizide was loaded to the optimized SNEDDS. In-vitro dilution of liquid SNEDDS resulted in a nanoemulsion with a mean droplet size of 29.4 nm. TEM studies of diluted liquid SNEDDS confirmed the uniform shape and size of the globules. The liquid SNEDDS was adsorbed onto calcium carbonate and talc to form solid SNEDDS. PXRD, DSC, and SEM results indicated that, the presence of glipizide as an amorphous and as a molecular dispersion state within solid SNEDDS. Glipizide dissolution improved significantly (p < 0.001) from the solid SNEDDS (∼100% in 15 min) as compared to the pure drug (18.37%) and commercial product (65.82) respectively. PMID:26594119

  2. Solubility of the Sodium and Ammonium Salts of Oxalic Acid in Water with Ammonium Sulfate.

    PubMed

    Buttke, Lukas G; Schueller, Justin R; Pearson, Christian S; Beyer, Keith D

    2016-08-18

    The solubility of the sodium and ammonium salts of oxalic acid in water with ammonium sulfate present has been studied using differential scanning calorimetry, X-ray crystallography, and infrared spectroscopy. The crystals that form from aqueous mixtures of ammonium sulfate/sodium hydrogen oxalate were determined to be sodium hydrogen oxalate monohydrate under low ammonium sulfate conditions and ammonium hydrogen oxalate hemihydrate under high ammonium sulfate conditions. Crystals from aqueous mixtures of ammonium sulfate/sodium oxalate were determined to be ammonium oxalate monohydrate under moderate to high ammonium sulfate concentrations and sodium oxalate under low ammonium sulfate concentrations. It was also found that ammonium sulfate enhances the solubility of the sodium oxalate salts (salting in effect) and decreases the solubility of the ammonium oxalate salts (salting out effect). In addition, a partial phase diagram for the ammonium hydrogen oxalate/water system was determined.

  3. Solubility of the Sodium and Ammonium Salts of Oxalic Acid in Water with Ammonium Sulfate.

    PubMed

    Buttke, Lukas G; Schueller, Justin R; Pearson, Christian S; Beyer, Keith D

    2016-08-18

    The solubility of the sodium and ammonium salts of oxalic acid in water with ammonium sulfate present has been studied using differential scanning calorimetry, X-ray crystallography, and infrared spectroscopy. The crystals that form from aqueous mixtures of ammonium sulfate/sodium hydrogen oxalate were determined to be sodium hydrogen oxalate monohydrate under low ammonium sulfate conditions and ammonium hydrogen oxalate hemihydrate under high ammonium sulfate conditions. Crystals from aqueous mixtures of ammonium sulfate/sodium oxalate were determined to be ammonium oxalate monohydrate under moderate to high ammonium sulfate concentrations and sodium oxalate under low ammonium sulfate concentrations. It was also found that ammonium sulfate enhances the solubility of the sodium oxalate salts (salting in effect) and decreases the solubility of the ammonium oxalate salts (salting out effect). In addition, a partial phase diagram for the ammonium hydrogen oxalate/water system was determined. PMID:27482644

  4. Characterization of a soluble phosphatidic acid phosphatase in bitter melon (Momordica charantia).

    PubMed

    Cao, Heping; Sethumadhavan, Kandan; Grimm, Casey C; Ullah, Abul H J

    2014-01-01

    Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initial step towards understanding the biochemical mechanism of fatty acid accumulation in bitter melon seeds, this study focused on a soluble phosphatidic acid phosphatase (PAP, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) that hydrolyzes the phosphomonoester bond in phosphatidate yielding diacylglycerol and P(i). PAPs are typically categorized into two subfamilies: Mg(2+)-dependent soluble PAP and Mg(2+)-independent membrane-associated PAP. We report here the partial purification and characterization of an Mg(2+)-independent PAP activity from developing cotyledons of bitter melon. PAP protein was partially purified by successive centrifugation and UNOsphere Q and S columns from the soluble extract. PAP activity was optimized at pH 6.5 and 53-60 °C and unaffected by up to 0.3 mM MgCl2. The K(m) and Vmax values for dioleoyl-phosphatidic acid were 595.4 µM and 104.9 ηkat/mg of protein, respectively. PAP activity was inhibited by NaF, Na(3)VO(4), Triton X-100, FeSO4 and CuSO4, but stimulated by MnSO4, ZnSO4 and Co(NO3)2. In-gel activity assay and mass spectrometry showed that PAP activity was copurified with a number of other proteins. This study suggests that PAP protein is probably associated with other proteins in bitter melon seeds and that a new class of PAP exists as a soluble and Mg(2+)-independent enzyme in plants. PMID:25203006

  5. Solubility of ammonium acid urate nephroliths from bottlenose dolphins (Tursiops truncatus).

    PubMed

    Argade, Sulabha; Smith, Cynthia R; Shaw, Timothy; Zupkas, Paul; Schmitt, Todd L; Venn-Watson, Stephanie; Sur, Roger L

    2013-12-01

    Nephrolithiasis has been identified in managed populations of bottlenose dolphins (Tursiops truncatus); most of these nephroliths are composed of 100% ammonium acid urate (AAU). Several therapies are being investigated to treat and prevent nephrolithiasis in dolphins including the alkalization of urine for dissolution of nephroliths. This study evaluates the solubility of AAU nephroliths in a phosphate buffer, pH range 6.0-8.0, and in a carbonate-bicarbonate buffer, pH range 9.0-10.8. AAU nephroliths were obtained from six dolphins and solubility studies were conducted using reverse-phase high performance liquid chromatography with ultraviolet detection at 290 nm. AAU nephroliths were much more soluble in a carbonate-bicarbonate buffer, pH range 9.0-10.8 compared to phosphate buffer pH range 6.0-8.0. In the pH range 6.0-8.0, the solubility was 45% lower in potassium phosphate buffer compared to sodium phosphate buffer. When citrate was used along with phosphate in the same pH range, the solubility was improved by 13%. At pH 7 and pH 8, 150 mM ionic strength buffer was optimum for dissolution. In summary, adjustment of urinary pH alone does not appear to be a useful way to treat AAU stones in bottlenose dolphins. Better understanding of the pathophysiology of AAU nephrolithiasis in dolphins is needed to optimize kidney stone prevention and treatment. PMID:24450043

  6. Hygroscopic properties of internally mixed particles composed of NaCl and water-soluble organic acids.

    PubMed

    Ghorai, Suman; Wang, Bingbing; Tivanski, Alexei; Laskin, Alexander

    2014-02-18

    Atmospheric aging of naturally emitted marine aerosol often leads to formation of internally mixed particles composed of sea salts and water-soluble organic compounds of anthropogenic origin. Mixing of sea salt and organic components has profound effects on the evolving chemical composition and hygroscopic properties of the resulted particles, which are poorly understood. Here, we have studied chemical composition and hygroscopic properties of laboratory generated NaCl particles mixed with malonic acid (MA) and glutaric acid (GA) at different molar ratios using micro-FTIR spectroscopy, atomic force microscopy, and X-ray elemental microanalysis. Hygroscopic properties of internally mixed NaCl and organic acid particles were distinctly different from pure components and varied significantly with the type and amount of organic compound present. Experimental results were in a good agreement with the AIM modeling calculations of gas/liquid/solid partitioning in studied systems. X-ray elemental microanalysis of particles showed that Cl/Na ratio decreased with increasing organic acid component in the particles with MA yielding lower ratios relative to GA. We attribute the depletion of chloride to the formation of sodium malonate and sodium glutarate salts resulted by HCl evaporation from dehydrating particles. PMID:24437520

  7. Hygroscopic Properties of Internally Mixed Particles Composed of NaCl and Water-Soluble Organic Acids

    SciTech Connect

    Ghorai, Suman; Wang, Bingbing; Tivanski, Alexei V.; Laskin, Alexander

    2014-02-18

    Atmospheric aging of naturally emitted marine aerosol often leads to formation of internally mixed particles composed of sea salts and water soluble organic compounds of anthropogenic origin. Mixing of sea salt and organic components has profound effects on the evolving chemical composition and hygroscopic properties of the resulted particles, which are poorly understood. Here, we have studied chemical composition and hygroscopic properties of laboratory generated NaCl particles mixed with malonic acid (MA) and glutaric acid (GA) at different molar ratios using micro-FTIR spectroscopy and X-ray elemental microanalysis.Hygroscopic properties of inte rnally mixed NaCl and organic acid particles were distinctly different from pure components and varied significantly with the type and amount of organic compound present. Experimental results were in a good agreement with the AIM modeling calculations of gas/liquid/solid partitioning in studied systems. X-ray elemental microanalysis of particles showed that Cl/Na ratio decreased with increasing organic acid component in the particles with MA yielding lower ratios relative to GA. We attribute the depletion of chloride to the formation of Na-malonate and Na-glutarate salts resulted by HCl evaporation from dehydrating particles.

  8. Modified mass action law-based model to correlate the solubility of solids and liquids in entrained supercritical carbon dioxide.

    PubMed

    González, J C; Vieytes, M R; Botana, A M; Vieites, J M; Botana, L M

    2001-02-23

    The solubility of solids and liquids in supercritical CO2 with added entrainers was modeled with a modified version of the equation of Chrastil to include the effect of entrainers. By considering the formation of the solute-entrainer-solvent complexes an equation is obtained which predicts an exponential increase of solubility with fluid density and/or entrainer concentration. The correlating model was tested by non-linear regression through a computerized iterative process for several systems where an entrainer was present. Four experimental parameters are easily regressed from experimental data, hence the corresponding properties of components such as chemical potentials or critical parameters are not needed. Instead of its simplicity, this thermodynamical model provided a good correlation of the solubility enhancement in the presence of entrainer effect. PMID:11263564

  9. Acid properties of solid acid catalysts characterized by solid-state 31P NMR of adsorbed phosphorous probe molecules.

    PubMed

    Zheng, Anmin; Huang, Shing-Jong; Liu, Shang-Bin; Deng, Feng

    2011-09-01

    A brief review is presented on acidity characterization of solid acid catalysts by means of solid-state phosphor-31 magic-angle-spinning nuclear magnetic resonance ((31)P MAS NMR) spectroscopy using phosphor-containing molecules as probes. It is emphasized that such a simple approach using (31)P MAS NMR of adsorbed phosphorous probe molecules, namely trimethylphosphine (TMP) and trialkylphosphine oxides (R(3)PO), represents a unique technique in providing detailed qualitative and quantitative features, viz. type, strength, distribution, and concentration of acid sites in solid acid catalysts. In particular, it will be shown that when applied with a proper choice of probe molecules with varied sizes and results obtained from elemental analysis, the amounts and locations (intracrystalline vs. extracrystalline) of different types (Brønsted vs. Lewis) of acid sites may be determined. In addition, by incorporating the NMR results with that obtained from theoretical density functional theory (DFT) calculations, correlations between the (31)P chemical shifts (δ(31)P) and acidic strengths of Brønsted and Lewis acid sites may also be derived, facilitating a suitable acidity scale for solid acid catalysts.

  10. Effect of magnesium carbonate on the solubility, dissolution and oral bioavailability of fenofibric acid powder as an alkalising solubilizer.

    PubMed

    Kim, Kyeong Soo; Kim, Jeong Hyun; Jin, Sung Giu; Kim, Dong Wuk; Kim, Dong Shik; Kim, Jong Oh; Yong, Chul Soon; Cho, Kwan Hyung; Li, Dong Xun; Woo, Jong Soo; Choi, Han-Gon

    2016-04-01

    To investigate the possibility of developing a novel oral pharmaceutical product using fenofibric acid instead of choline fenofibrate, the powder properties, solubility, dissolution and pharmacokinetics in rats of fenofibrate, choline fenofibrate and fenofibric acid were compared. Furthermore, the effect of magnesium carbonate, an alkalising agent on the solubility, dissolution and oral bioavailability of fenofibric acid was assessed, a mixture of fenofibric acid and magnesium carbonate being prepared by simple blending at a weight ratio of 2/1. The three fenofibrate derivatives showed different particle sizes and melting points with similar crystalline shape. Fenofibric acid had a significantly higher aqueous solubility and dissolution than fenofibrate, but significantly lower solubility and dissolution than choline fenofibrate. However, the fenofibric acid/magnesium carbonate mixture greatly improved the solubility and dissolution of fenofibric acid with an enhancement to levels similar with those for choline fenofibrate. Fenofibric acid gave lower plasma concentrations, AUC and Cmax values compared to choline fenofibrate in rats. However, the mixture resulted in plasma concentrations, AUC and Cmax values levels not significantly different from those for choline fenofibrate. Specifically, magnesium carbonate increased the aqueous solubility, dissolution and bioavailability of fenofibric acid by about 7.5-, 4- and 1.6-fold, respectively. Thus, the mixture of fenofibric acid and magnesium carbonate at the weight ratio of 2/1 might be a candidate for an oral pharmaceutical product with improved oral bioavailability. PMID:26992922

  11. Major Source of Error in QSPR Prediction of Intrinsic Thermodynamic Solubility of Drugs: Solid vs Nonsolid State Contributions?

    PubMed

    Abramov, Yuriy A

    2015-06-01

    The main purpose of this study is to define the major limiting factor in the accuracy of the quantitative structure-property relationship (QSPR) models of the thermodynamic intrinsic aqueous solubility of the drug-like compounds. For doing this, the thermodynamic intrinsic aqueous solubility property was suggested to be indirectly "measured" from the contributions of solid state, ΔGfus, and nonsolid state, ΔGmix, properties, which are estimated by the corresponding QSPR models. The QSPR models of ΔGfus and ΔGmix properties were built based on a set of drug-like compounds with available accurate measurements of fusion and thermodynamic solubility properties. For consistency ΔGfus and ΔGmix models were developed using similar algorithms and descriptor sets, and validated against the similar test compounds. Analysis of the relative performances of these two QSPR models clearly demonstrates that it is the solid state contribution which is the limiting factor in the accuracy and predictive power of the QSPR models of the thermodynamic intrinsic solubility. The performed analysis outlines a necessity of development of new descriptor sets for an accurate description of the long-range order (periodicity) phenomenon in the crystalline state. The proposed approach to the analysis of limitations and suggestions for improvement of QSPR-type models may be generalized to other applications in the pharmaceutical industry.

  12. A soluble acid invertase is directed to the vacuole by a signal anchor mechanism.

    PubMed

    Rae, Anne L; Casu, Rosanne E; Perroux, Jai M; Jackson, Mark A; Grof, Christopher P L

    2011-06-15

    Enzyme activities in the vacuole have an important impact on the net concentration of sucrose. In sugarcane (Saccharum hybrid), immunolabelling demonstrated that a soluble acid invertase (β-fructofuranosidase; EC 3.2.1.26) is present in the vacuole of storage parenchyma cells during sucrose accumulation. Examination of sequences from sugarcane, barley and rice showed that the N-terminus of the invertase sequence contains a signal anchor and a tyrosine motif, characteristic of single-pass membrane proteins destined for lysosomal compartments. The N-terminal peptide from the barley invertase was shown to be capable of directing the green fluorescent protein to the vacuole in sugarcane cells. The results suggest that soluble acid invertase is sorted to the vacuole in a membrane-bound form.

  13. Solubilities of stearic acid, stearyl alcohol, and arachidyl alcohol in supercritical carbon dioxide at 35[degree]C

    SciTech Connect

    Iwai, Yoshio; Koga, Yoshio; Maruyama, Hironori; Arai, Yasuhiko . Dept. of Chemical Engineering)

    1993-10-01

    The solubilities of stearic acid (octadecanoic acid), stearyl alcohol (1-octadecanol), and arachidyl alcohol (1-eicosanol) in supercritical carbon dioxide were measured by using a flow-type apparatus at 35 C up to 23.7 MPa. The solubilities of those substances and other fatty acids and higher alcohols in supercritical carbon dioxide at 35 C were correlated by a solution model based on the regular solution model coupled with the Flory-Huggins theory.

  14. Sialic Acid Is Required for Neuronal Inhibition by Soluble MAG but not for Membrane Bound MAG

    PubMed Central

    Al-Bashir, Najat; Mellado, Wilfredo; Filbin, Marie T.

    2016-01-01

    Myelin-Associated Glycoprotein (MAG), a major inhibitor of axonal growth, is a member of the immunoglobulin (Ig) super-family. Importantly, MAG (also known as Siglec-4) is a member of the Siglec family of proteins (sialic acid-binding, immunoglobulin-like lectins), MAG binds to complex gangliosides, specifically GD1a and/or GT1b. Therefore, it has been proposed as neuronal receptors for MAG inhibitory effect of axonal growth. Previously, we showed that MAG binds sialic acid through domain 1 at Arg118 and is able to inhibit axonal growth through domain 5. We developed a neurite outgrowth (NOG) assay, in which both wild type MAG and mutated MAG (MAG Arg118) are expressed on cells. In addition we also developed a soluble form NOG in which we utilized soluble MAG-Fc and mutated MAG (Arg118-Fc). Only MAG-Fc is able to inhibit NOG, but not mutated MAG (Arg118)-Fc that has been mutated at its sialic acid binding site. However, both forms of membrane bound MAG- and MAG (Arg118)- expressing cells still inhibit NOG. Here, we review various results from different groups regarding MAG’s inhibition of axonal growth. Also, we propose a model in which the sialic acid binding is not necessary for the inhibition induced by the membrane form of MAG, but it is necessary for the soluble form of MAG. This finding highlights the importance of understanding the different mechanisms by which MAG inhibits NOG in both the soluble fragmented form and the membrane-bound form in myelin debris following CNS damage. PMID:27065798

  15. Non-destructive determination of soluble solids in chufa by FT-near infrared (FT-NIR) spectroscopy

    NASA Astrophysics Data System (ADS)

    Ma, Guang; Ying, Yibin; Lu, Huishan; Fu, Xiaping; Yu, Haiyan; Liu, Yande

    2005-11-01

    The near infrared (NIR) method based on fibre-optic FT-NIR spectrometer was tested to determine soluble solids content (SSC) non-destructively in chufa (Eleocharis tuberose schult). A total of 240 chufas (120 of cv. 'Jinhua' and 120 of cv. 'Yongkang') sampled from eight positions in the different fields to increase variation in soluble solids content, were measured after 2-days storage and the measurements randomly assigned to a calibration data set and a prediction data set. Thus the calibration set and the prediction set represented exactly the same distribution. The calibration data set was used to select the wavelengths best correlated with Brix and different regression methods (partial least squares (PLS) regression and multiple linear regression (MLR)) that was applied to calculate the Brix value in the prediction data set. The most significant r (0.9056) was found with the first derivative of log (1/R) (where R reflectance), yielding standard error of calibration (SEC)=0.545 Brix, standard error of prediction (SEP)=0.632 Brix. Analysis of different methods performed on the actual and the predicted Brix showed PLS is better than MLR. This NIR method seems reliable for determining soluble solids contents of chufa non-destructively, and could prove useful for it.

  16. Identification of a soluble diacylglycerol kinase required for lipoteichoic acid production in Bacillus subtilis.

    PubMed

    Jerga, Agoston; Lu, Ying-Jie; Schujman, Gustavo E; de Mendoza, Diego; Rock, Charles O

    2007-07-27

    Diacylglycerol kinases (DagKs) are key enzymes in lipid metabolism that function to reintroduce diacylglycerol formed from the hydrolysis of phospholipids into the biosynthetic pathway. Bacillus subtilis is a prototypical Gram-positive bacterium with a lipoteichoic acid structure containing repeating units of sn-glycerol-1-P groups derived from phosphatidylglycerol head groups. The B. subtilis homolog of the prokaryotic DagK gene family (dgkA; Pfam01219) was not a DagK but rather was an undecaprenol kinase. The three members of the soluble DagK protein family (Pfam00781) in B. subtilis were tested by complementation of an E. coli dgkA mutant, and only the essential yerQ gene possessed DagK activity. This gene was dubbed dgkB, and the soluble protein product was purified, and its DagK activity was verified in vitro. Conditional inactivation of dgkB led to the accumulation of diacylglycerol and the cessation of lipoteichoic acid formation in B. subtilis. This study identifies a soluble protein encoded by the dgkB (yerQ) gene as an essential kinase in the diacylglycerol cycle that drives lipoteichoic acid production.

  17. Adaption of kinetics to solid electrolyte interphase layer formation and application to electrolyte-soluble reaction products

    NASA Astrophysics Data System (ADS)

    Gourdin, Gerald; Zheng, Dong; Qu, Deyang

    2015-12-01

    During the electrochemical lithiation of a carbon electrode, carbonate-based electrolytes react with the electrode surface and undergo reductive decomposition to form a solid electrolyte interphase (SEI) layer that passivates the surface of the carbon electrode. In addition, reduction of the electrolyte also results in the generation of electrolyte-soluble products. Structural similarities between the soluble and insoluble products provide an opportunity to examine the formation kinetics of the SEI layer through an analysis of the kinetic behavior of the soluble products. In this work, the electrolyte-soluble products generated by reductive decomposition of a baseline electrolyte were analyzed at different stages and at different hold times during the initial lithiation of an amorphous carbon electrode. A statistical regression analysis of that data was used to produce a representative lithiation experiment from which was calculated the potential-dependent formation rates for the soluble decomposition products. The predicted formation rate data was fitted using an adapted rate equation that accounts for the effect of the SEI layer to obtain estimated formation rate constants and redox potentials.

  18. Automated protein hydrolysis delivering sample to a solid acid catalyst for amino acid analysis.

    PubMed

    Masuda, Akiko; Dohmae, Naoshi

    2010-11-01

    In this study, we developed an automatic protein hydrolysis system using strong cation-exchange resins as solid acid catalysts. Examining several kinds of inorganic solid acids and cation-exchange resins, we found that a few cation-exchange resins worked as acid catalysts for protein hydrolysis when heated in the presence of water. The most efficient resin yielded amounts of amino acids that were over 70% of those recovered after conventional hydrolysis with hydrochloric acid and resulted in amino acid compositions matching the theoretical values. The solid-acid hydrolysis was automated by packing the resin into columns, combining the columns with a high-performance liquid chromatography system, and heating them. The amino acids that constitute a protein can thereby be determined, minimizing contamination from the environment.

  19. Development and characterization of solid dispersion-microsphere controlled release system for poorly water-soluble drug.

    PubMed

    Malipeddi, Venkata Ramana; Dua, Kamal; Awasthi, Rajendra

    2016-10-01

    The present study aimed to improve solubility and prolong the release duration of a poorly soluble drug using a combination of two different types of formulations (solid dispersion and microspheres). The solid dispersions were prepared by fusion method using urea and mannitol as hydrophilic carriers. Microspheres were prepared by solvent evaporation method using Eudragit L-100 (EL100) and Eudragit RS PO (ERS) as rate-controlling polymers. Flurbiprofen (FBP)-urea (1:2) solid dispersion and microspheres of FBP-EL-100-ERS (1:0.25:0.75) were used for the development of controlled release formulation by mixing them in different proportions. The FBP-containing formulations were evaluated for percentage yield, drug content, morphology, in vitro release, and in vivo anti-inflammatory activity. The best selected formulation was further evaluated for the controlled and improved effects. SEM photomicrograph confirmed the spherical shape of microspheres and with particle size in the range of 73.5-85.4 μm. In vitro release of FBP from controlled release formulations indicated that the formulation containing solid dispersion:microspheres (1:0.5) yielded prolonged effect up to 10 h. The release kinetics followed zero-order, and the mechanism of drug release was found to be diffusion rate controlled. This formulation had shown better inhibition of edema of rat paw up to 16 h and identified as a suitable product for controlled delivery of FBP. In conclusion, the concept of using a binary mixture of solid dispersion and microspheres can be used for other drugs that exhibit a poor solubility in stomach pH and a faster release in intestinal pH.

  20. Development and characterization of solid dispersion-microsphere controlled release system for poorly water-soluble drug.

    PubMed

    Malipeddi, Venkata Ramana; Dua, Kamal; Awasthi, Rajendra

    2016-10-01

    The present study aimed to improve solubility and prolong the release duration of a poorly soluble drug using a combination of two different types of formulations (solid dispersion and microspheres). The solid dispersions were prepared by fusion method using urea and mannitol as hydrophilic carriers. Microspheres were prepared by solvent evaporation method using Eudragit L-100 (EL100) and Eudragit RS PO (ERS) as rate-controlling polymers. Flurbiprofen (FBP)-urea (1:2) solid dispersion and microspheres of FBP-EL-100-ERS (1:0.25:0.75) were used for the development of controlled release formulation by mixing them in different proportions. The FBP-containing formulations were evaluated for percentage yield, drug content, morphology, in vitro release, and in vivo anti-inflammatory activity. The best selected formulation was further evaluated for the controlled and improved effects. SEM photomicrograph confirmed the spherical shape of microspheres and with particle size in the range of 73.5-85.4 μm. In vitro release of FBP from controlled release formulations indicated that the formulation containing solid dispersion:microspheres (1:0.5) yielded prolonged effect up to 10 h. The release kinetics followed zero-order, and the mechanism of drug release was found to be diffusion rate controlled. This formulation had shown better inhibition of edema of rat paw up to 16 h and identified as a suitable product for controlled delivery of FBP. In conclusion, the concept of using a binary mixture of solid dispersion and microspheres can be used for other drugs that exhibit a poor solubility in stomach pH and a faster release in intestinal pH. PMID:27343081

  1. Molecular interaction studies of amorphous solid dispersions of the antimelanoma agent betulinic acid.

    PubMed

    Yu, Meiki; Ocando, Joseph E; Trombetta, Louis; Chatterjee, Parnali

    2015-04-01

    Betulinic acid (BA), a novel natural product with antimelanoma activity, has poor aqueous solubility (<0.1 μg/mL) and therefore exhibits poor bioavailability. The purpose of this study was to explore the feasibility of preparing BA solid dispersions (BA-SDs) with hydrophilic polymers to enhance the aqueous solubility of BA. Melt-quenched solid dispersions (MQ-SDs) of BA were prepared at various ratios with the hydrophilic polymers including Soluplus, HPMCAS-HF, Kollidon VA64, Kollidon K90, and Eudragit RLPO. BA was found to be miscible in all polymers at a 1:4 (w/w) ratio by modulated differential scanning calorimetry (MDSC). BA/Soluplus MQ-SD exhibited the highest solubility in simulated body fluids followed by BA/Kollidon VA64 MQ-SD. The MQ-SDs of BA/Soluplus, BA/HPMCAS-HF, and BA/Kollidon VA64 were found to be amorphous as indicated by X-ray powder diffraction (XRPD) studies. Fourier transform infra-red (FT-IR) studies indicated molecular interactions between BA and Soluplus. Our preliminary screening of polymers indicates that Soluplus and Kollidon VA64 exhibit the greatest potential to form BA-SDs. PMID:25331193

  2. Molecular interaction studies of amorphous solid dispersions of the antimelanoma agent betulinic acid.

    PubMed

    Yu, Meiki; Ocando, Joseph E; Trombetta, Louis; Chatterjee, Parnali

    2015-04-01

    Betulinic acid (BA), a novel natural product with antimelanoma activity, has poor aqueous solubility (<0.1 μg/mL) and therefore exhibits poor bioavailability. The purpose of this study was to explore the feasibility of preparing BA solid dispersions (BA-SDs) with hydrophilic polymers to enhance the aqueous solubility of BA. Melt-quenched solid dispersions (MQ-SDs) of BA were prepared at various ratios with the hydrophilic polymers including Soluplus, HPMCAS-HF, Kollidon VA64, Kollidon K90, and Eudragit RLPO. BA was found to be miscible in all polymers at a 1:4 (w/w) ratio by modulated differential scanning calorimetry (MDSC). BA/Soluplus MQ-SD exhibited the highest solubility in simulated body fluids followed by BA/Kollidon VA64 MQ-SD. The MQ-SDs of BA/Soluplus, BA/HPMCAS-HF, and BA/Kollidon VA64 were found to be amorphous as indicated by X-ray powder diffraction (XRPD) studies. Fourier transform infra-red (FT-IR) studies indicated molecular interactions between BA and Soluplus. Our preliminary screening of polymers indicates that Soluplus and Kollidon VA64 exhibit the greatest potential to form BA-SDs.

  3. Cellular fatty acid and soluble protein composition of Actinobacillus actinomycetemcomitans and related organisms.

    PubMed Central

    Calhoon, D A; Mayberry, W R; Slots, J

    1981-01-01

    The cellular fatty acid and protein content of twenty-five representative strains of Actinobacillus actinomycetecomitans isolated from juvenile and adult periodontitis patients was compared to that of 15 reference strains of oral and nonoral Actinobacillus species and Haemophilus aphrophilus. Trimethylsilyl derivatives of the fatty acid methyl esters were analyzed by gas-liquid chromatography. The predominant fatty acids of all 40 strains examined were 14:0, 3-OH 14:0, 16 delta, and 16:0. Actinobacillus seminis (ATCC 15768) was unlike the other strains examined because of a greater amount of 14:0 detected. The soluble protein analysis using polyacrylamide gel electrophoresis revealed that A. actinomycetemcomitans, H. aphrophilus, and nonoral Actinobacillus species possessed distinct protein profiles attesting to the validity of separating these organisms into different species. Established biotypes of A. actinomycetemcomitans could not be differentiated on the basis of fatty acid or protein profiles. PMID:7287893

  4. Solubility of calcium salts of unconjugated and conjugated natural bile acids.

    PubMed

    Gu, J J; Hofmann, A F; Ton-Nu, H T; Schteingart, C D; Mysels, K J

    1992-05-01

    The approximate solubility products of the calcium salts of ten unconjugated bile acids and several taurine conjugated bile acids were determined. The formation of micelles, gels, and/or precipitates in relation to Ca2+,Na+, and bile salt concentration was summarized by "phase maps." Because the ratio of Ca2+ to bile salt in the precipitates was ca. 1:2, and the activity of Ca2+ but not that of bile salt (BA-) could be measured, the ion product of aCa2+ [BA-]2 was calculated. The ion product (= Ksp) ranged over nine orders of magnitude and the solubility thus ranged over three orders of magnitude; its value depended on the number and orientation of the hydroxyl groups in the bile acid. Ion products (in units of 10(-9) mol/l)3 were as follows: cholic (3 alpha OH,7 alpha OH,12 alpha OH) 640; ursocholic (3 alpha OH,7 beta OH,12 alpha OH) 2300; hyocholic (3 alpha OH,6 alpha OH,7 alpha OH) 11; ursodeoxycholic (3 alpha OH,7 beta OH) 91; chenodeoxycholic (3 alpha OH,7 alpha OH) 10; deoxycholic (3 alpha OH,12 alpha OH) 1.5; 12-epideoxycholic (lagodeoxycholic, 3 alpha OH,12 beta OH) 2.2; hyodeoxycholic (3 alpha OH,6 alpha OH) 0.7; and lithocholic (3 alpha OH) 0.00005. The critical micellization temperature of the sodium salt of murideoxycholic acid (3 alpha OH,6 beta OH) was greater than 100 degrees C, and its Ca2+ salt was likely to be very insoluble. Taurine conjugates were much more soluble than their corresponding unconjugated derivatives: chenodeoxycholyltaurine, 384; deoxycholyltaurine, 117; and cholyltaurine, greater than 10,000. Calcium salts of unconjugated bile acids precipitated rapidly in contrast to those of glycine conjugates which were metastable for months. Thus, hepatic conjugation of bile acids with taurine or glycine not only enhances solubility at acidic pH, but also at Ca2+ ion concentrations present in bile and intestinal content.

  5. Solid Acid Fuel Cell Stack for APU Applications

    SciTech Connect

    Duong, Hau H.

    2011-04-15

    Solid acid fuel cell technology affords the opportunity to operate at the 200-300 degree centigrade regime that would allow for more fuel flexibility, compared to polymer electrode membrane fuel cell, while avoiding the relatively more expensive and complex system components required by solid oxide fuel cell. This project addresses many factors such as MEA size scalability, fuel robustness, stability, etc., that are essential for successful commercialization of the technology.

  6. Reactions Between Water Soluble Organic Acids and Nitrates in Atmospheric Aerosols: Recycling of Nitric Acid and Formation of Organic Salts

    SciTech Connect

    Wang, Bingbing; Laskin, Alexander

    2014-03-25

    Atmospheric particles often include a complex mixture of nitrate and secondary organic materials accumulated within the same individual particles. Nitrate as an important inorganic component can be chemically formed in the atmosphere. For instance, formation of sodium nitrate (NaNO3) and calcium nitrate Ca(NO3)2 when nitrogen oxide and nitric acid (HNO3) species react with sea salt and calcite, respectively. Organic acids contribute a significant fraction of photochemically formed secondary organics that can condense on the preexisting nitrate-containing particles. Here, we present a systematic microanalysis study on chemical composition of laboratory generated particles composed of water soluble organic acids and nitrates (i.e. NaNO3 and Ca(NO3)2) investigated using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and Fourier transform infrared micro-spectroscopy (micro-FTIR). The results show that water-soluble organic acids can react with nitrates releasing gaseous HNO3 during dehydration process. These reactions are attributed to acid displacement of nitrate with weak organic acids driven by the evaporation of HNO3 into gas phase due to its relatively high volatility. The reactions result in significant nitrate depletion and formation of organic salts in mixed organic acids/nitrate particles that in turn may affect their physical and chemical properties relevant to atmospheric environment and climate. Airborne nitrate concentrations are estimated by thermodynamic calculations corresponding to various nitrate depletions in selected organic acids of atmospheric relevance. The results indicate a potential mechanism of HNO3 recycling, which may further affect concentrations of gas- and aerosol-phase species in the atmosphere and the heterogeneous reaction chemistry between them.

  7. Quench-Condensed Microalloyed Particles: a Microscopic View of Solid Solubility and Metastability

    NASA Astrophysics Data System (ADS)

    Lamberti, Vincent Edward

    Solid solubility and metastability in noble-metal and iron-silver alloys have been studied from the perspective of microalloyed particles. Samples were obtained through a novel, gram-scale technique that consisted of cocondensation of two elemental metal vapors with a large excess of inert gas on the reaction surface of a rotating cryostat at 77 K. This technique permitted greater control of both particle size and composition than conventional gas aggregation methods. The chemical and physical characteristics of the microalloys have been elaborated through chemical analysis, x-ray diffraction, electron microscopy, temperature-programmed mass spectrometry, EXAFS, XPS and Moessbauer spectroscopy. Electron microscopy indicated the microstructures of copper-gold and copper-silver microalloys prepared in sulfur hexafluoride to consist of discrete collections of crystallites suspended in amorphous "baths". The average dimensions of the crystallites were <100 A, while the aggregates spanned hundreds of nanometers. The microstructures of both systems were metastable. The EXAFS of a copper-silver microalloy showed it to be stiffer, as well as more disordered, than a homometallic copper product. The EXAFS also showed no detectable Cu-Ag contacts, but suggested the existence (through a "missing-atom" effect) of a large number of disordered copper sites. Moessbauer spectra of an iron -silver microalloy prepared in xenon revealed the presence of a superparamagnetic alloy phase characterized by a blocking temperature of approximately 45 K. Cocondensations of iron vapor with excess sulfur hexafluoride produced ultrafine (dimensions ~ 100 A), amorphous particles that were decorated with a -CF_{2^-} polymer. The formation of the polymer was attributed to reaction of the iron with the matrix and adventitious organic compounds--that is, to activation of S-F and C-H bonds. Matrix isolation experiments indicated that, although inert in their ground-state configuration, photoexcited (4p

  8. Solubility and Reaction Rates of Aluminum Solid Phases Under Geothermal Conditions

    SciTech Connect

    Benezeth, P.; Palmer, D.A.; Wesolowski, D.J.; Anovitz, L.M.

    2000-05-28

    Experimental studies involving equilibrium solubility and dissolution/precipitation rates were initiated on aluminum hydroxide phases prevalent under geothermal reservoir conditions. A large capacity, hydrogen-electrode concentration cell (HECC) was constructed specifically for this purpose.

  9. Chemical constituents: water-soluble vitamins, free amino acids and sugar profile from Ganoderma adspersum.

    PubMed

    Kıvrak, İbrahim

    2015-01-01

    Ganoderma adspersum presents a rigid fruiting body owing to chitin content and having a small quantity of water or moisture. The utility of bioactive constituent of the mushroom can only be available by extraction for human usage. In this study, carbohydrate, water-soluble vitamin compositions and amino acid contents were determined in G. adspersum mushroom. The composition in individual sugars was determined by HPLC-RID, mannitol (13.04 g/100 g) and trehalose (10.27 g/100 g) being the most abundant sugars. The examination of water-soluble vitamins and free amino acid composition was determined by UPLC-ESI-MS/MS. Essential amino acid constituted 67.79% of total amino acid, which is well worth the attention with regard to researchers and consumers. In addition, G. adspersum, which is also significantly rich in B group vitamins and vitamin C, can provide a wide range of notable applications in the pharmaceutics, cosmetics, food and dietary supplement industries. G. adspersum revealed its value for pharmacy and nutrition fields.

  10. Phosphorylated Mesoporous Carbon as a Solid Acid Catalyst

    SciTech Connect

    Dai, Sheng; Mayes, Richard T; Fulvio, Pasquale F; Ma, Zhen

    2011-01-01

    Mesoporous carbon catalyst supports are attractive due to their wide chemical stability while potentially increasing masstransport through and providing a path for larger molecules to access catalytic sites. Herein we report the synthesis of a 10 phosphorylated mesoporous carbon solid-acid catalyst characterized by NH3-TPD and isopropanol dehydration.

  11. Immobilization of high concentrations of soluble Mn(II) from electrolytic manganese solid waste using inorganic chemicals.

    PubMed

    Du, Bing; Hou, Deyin; Duan, Ning; Zhou, Changbo; Wang, Jun; Dan, Zhigang

    2015-05-01

    Electrolytic manganese solid waste (EMSW) is a by-product of electrolytic manganese production and generally contains a high concentration of soluble Mn(II) (2000-3000 mg/L). Millions of tons of EMSW are stored in China, and the environmental pollution caused by manganese in this waste product is concerning. Unfortunately, little attention has been paid to the immobilization of manganese from industrial solid waste because manganese is absent from toxicological identification standards, and there is a lack of relevant quality standards in China. The objectives of this study were to immobilize soluble Mn(II) using chemical reagents, to analyze the immobilization mechanism, and to identify the most economical reagents. We investigated the immobilization degrees of soluble Mn(II) achieved by the reagents quicklime (CaO), carbonates (NaHCO₃ and Na₂CO₃), phosphates (Na₃PO₄, Na₂HPO₄, NH₄H₂PO₄, and Ca₁₀(PO₄)₆(OH)₂), and caustic magnesia (MgO) both individually and in combination. Our results showed that the use of 9% CaO+ 5% NaHCO₃, 9% CaO+ 5% Na₃PO₄, 10% MgO alone, or with 1-5% NaHCO₃ or 1-5% Na₂CO₃ can reduce the amount of Mn(II) leached to 100 mg/kg when the eluate pH was in the range of 6-9. The most economical reagent treatments were determined using K-means cluster analysis. Analysis of the immobilization mechanism showed that CaO + NaHCO₃ may be favorable for immobilizing soluble Mn(II) as precipitation and oxidation products because the addition of NaHCO₃ releases OH(-) and buffers the system. PMID:25728200

  12. Immobilization of high concentrations of soluble Mn(II) from electrolytic manganese solid waste using inorganic chemicals.

    PubMed

    Du, Bing; Hou, Deyin; Duan, Ning; Zhou, Changbo; Wang, Jun; Dan, Zhigang

    2015-05-01

    Electrolytic manganese solid waste (EMSW) is a by-product of electrolytic manganese production and generally contains a high concentration of soluble Mn(II) (2000-3000 mg/L). Millions of tons of EMSW are stored in China, and the environmental pollution caused by manganese in this waste product is concerning. Unfortunately, little attention has been paid to the immobilization of manganese from industrial solid waste because manganese is absent from toxicological identification standards, and there is a lack of relevant quality standards in China. The objectives of this study were to immobilize soluble Mn(II) using chemical reagents, to analyze the immobilization mechanism, and to identify the most economical reagents. We investigated the immobilization degrees of soluble Mn(II) achieved by the reagents quicklime (CaO), carbonates (NaHCO₃ and Na₂CO₃), phosphates (Na₃PO₄, Na₂HPO₄, NH₄H₂PO₄, and Ca₁₀(PO₄)₆(OH)₂), and caustic magnesia (MgO) both individually and in combination. Our results showed that the use of 9% CaO+ 5% NaHCO₃, 9% CaO+ 5% Na₃PO₄, 10% MgO alone, or with 1-5% NaHCO₃ or 1-5% Na₂CO₃ can reduce the amount of Mn(II) leached to 100 mg/kg when the eluate pH was in the range of 6-9. The most economical reagent treatments were determined using K-means cluster analysis. Analysis of the immobilization mechanism showed that CaO + NaHCO₃ may be favorable for immobilizing soluble Mn(II) as precipitation and oxidation products because the addition of NaHCO₃ releases OH(-) and buffers the system.

  13. [The effect of terephthalic acid and film made from polyterephthalic acid esters on water soluble vitamins].

    PubMed

    Steiner, I

    1990-12-01

    Terephthalic acid is used for the production of polyterephthalic acid esters for foils that are applied for cooking, roasting, and baking; it is able to migrate as a monomer into foodstuffs. The effect of sodium terephthalate on vitamins such as thiamin, riboflavin, pyridoxine, and ascorbic acid at different conditions (variation of time and temperature); effects of a foil made of polyterephthalic acid esters was also tested. Thiamin and riboflavin are stabilized by sodium terephthalate while pyridoxine is decomposed faster, especially at higher temperatures. The tests of thiamin and riboflavin in the foils show similar results, whereas the losses of pyridoxine were not so high compared with the tests where sodium terephthalate had been added. Ascorbic acid is protected, too, by sodium terephthalate, except with long heating periods at a temperature of 220 degrees C.

  14. Soluble species in the Arctic summer troposphere - acidic gases, aerosols, and precipitation

    SciTech Connect

    Talbot, R.W.; Vijgen, A.S.; Harriss, R.C. Old Dominion Univ., Norfolk, VA )

    1992-10-01

    The large-scale spatial distribution from 0.15-to 6 km altitude in the North American Arctic troposphere of several soluble acidic gases and major aerosol species during the summertime is reported. The distribution is found to be compositionally consistent on a large spatial scale. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases while acidic sulfate aerosols dominate the particulate phase. There appears to be a surface source of NH3 over the pack ice which may originate from decay of dead marine organisms on the ice surface, evolution from surface ocean waters in open ice leads, or release from rotting sea ice. At low altitude over the pack ice this NH34 appears to partially neutralize aerosol acidity. Over sub-Arctic tundra in southeastern Alaska, inputs of marine biogenic sulfur from the Bering Sea appear to be an important source of boundary layer aerosol SO4(2-). The rainwater acidity over the tundra is typical of remote regions. 61 refs.

  15. Soluble species in the Arctic summer troposphere - Acidic gases, aerosols, and precipitation

    NASA Technical Reports Server (NTRS)

    Talbot, R. W.; Vijgen, A. S.; Harriss, R. C.

    1992-01-01

    The large-scale spatial distribution from 0.15-to 6 km altitude in the North American Arctic troposphere of several soluble acidic gases and major aerosol species during the summertime is reported. The distribution is found to be compositionally consistent on a large spatial scale. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases while acidic sulfate aerosols dominate the particulate phase. There appears to be a surface source of NH3 over the pack ice which may originate from decay of dead marine organisms on the ice surface, evolution from surface ocean waters in open ice leads, or release from rotting sea ice. At low altitude over the pack ice this NH34 appears to partially neutralize aerosol acidity. Over sub-Arctic tundra in southeastern Alaska, inputs of marine biogenic sulfur from the Bering Sea appear to be an important source of boundary layer aerosol SO4(2-). The rainwater acidity over the tundra is typical of remote regions.

  16. Wetting Kinetics: an Alternative Approach Towards Understanding the Enhanced Dissolution Rate for Amorphous Solid Dispersion of a Poorly Soluble Drug.

    PubMed

    Verma, Sanjay; Rudraraju, Varma S

    2015-10-01

    Developing amorphous solid dispersions of water-insoluble molecules using polymeric materials is a well-defined approach to improve the dissolution rate and bioavailability. While the selected polymer plays a vital role in stabilizing the amorphous solid dispersion physically, it is equally important to improve the dissolution profile by inhibiting crystallization from the supersaturated solution generated by dissolution of the amorphous material. Furthermore, understanding the mechanism of dissolution rate enhancement is of vital importance. In this work, wetting kinetics was taken up as an alternative approach for understanding the enhanced dissolution rate for amorphous solid dispersion of a poorly soluble drug. While cilostazol (CIL) was selected as the model drug, povidone (PVP), copovidone, and hypromellose (HPMC) were the polymers of choice. The concentrations against time profiles were evaluated for the supersaturated solutions of CIL in the presence and absence of the selected polymers. The degree of supersaturation increased significantly with increase in polymer content within the solid dispersion. While povidone was found to maintain the highest level of supersaturation for the greatest length of time both in dissolution and solution crystallization experiments, copovidone and hypromellose were found to be the less effective as crystallization inhibitor. The ability of polymers to generate and maintain supersaturated drug solutions was assessed by dissolution studies. The wetting kinetics was compared against the solid dispersion composition to establish a correlation with enhanced dissolution rate.

  17. Effects of alkaline pretreatments and acid extraction conditions on the acid-soluble collagen from grass carp (Ctenopharyngodon idella) skin.

    PubMed

    Liu, Dasong; Wei, Guanmian; Li, Tiancheng; Hu, Jinhua; Lu, Naiyan; Regenstein, Joe M; Zhou, Peng

    2015-04-01

    This study investigated the effects of alkaline pretreatments and acid extraction conditions on the production of acid-soluble collagen (ASC) from grass carp skin. For alkaline pretreatment, 0.05 and 0.1M NaOH removed non-collagenous proteins without significant loss of ASC at 4, 10, 15 and 20 °C; while 0.2 and 0.5M NaOH caused significant loss of ASC, and 0.5M NaOH caused structural modification of ASC at 15 and 20 °C. For acid extraction at 4, 10, 15 and 20 °C, ASC was partly extracted by 0.1 and 0.2M acetic acid, while 0.5 and 1.0M acetic acid resulted in almost complete extraction. The processing conditions involving 0.05-0.1M NaOH for pretreatment, 0.5M acetic acid for extraction and 4-20 °C for both pretreatment and extraction, produced ASC with the structural integrity being well maintained and hence were recommended to prepare ASC from grass carp skin in practical application.

  18. CARDIAC INJURY FROM LONG TERM EPISODIC EXPOSURE TO PARTICULATE MATTER (PM): SOLUBLE COMPONENTS OR SOLID PARTICLES?

    EPA Science Inventory

    Long-term exposure to PM has been associated with cardiac injury in rats. The purpose of this study was to investigate if cardiac injury was due to soluble metals (i.e., zinc), insoluble PM, or pulmonary injury/inflammation. Male Wistar Kyoto rats (n=8) were exposed intratracheal...

  19. Manufacturing of solid dispersions of poorly water soluble drugs by spray drying: formulation and process considerations.

    PubMed

    Paudel, Amrit; Worku, Zelalem Ayenew; Meeus, Joke; Guns, Sandra; Van den Mooter, Guy

    2013-08-30

    Spray drying is an efficient technology for solid dispersion manufacturing since it allows extreme rapid solvent evaporation leading to fast transformation of an API-carrier solution to solid API-carrier particles. Solvent evaporation kinetics certainly contribute to formation of amorphous solid dispersions, but also other factors like the interplay between the API, carrier and solvent, the solution state of the API, formulation parameters (e.g. feed concentration or solvent type) and process parameters (e.g. drying gas flow rate or solution spray rate) will influence the final physical structure of the obtained solid dispersion particles. This review presents an overview of the interplay between manufacturing process, formulation parameters, physical structure, and performance of the solid dispersions with respect to stability and drug release characteristics.

  20. Stearic acid and high molecular weight PEO as matrix for the highly water soluble metoprolol tartrate in continuous twin-screw melt granulation.

    PubMed

    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.

  1. Stearic acid and high molecular weight PEO as matrix for the highly water soluble metoprolol tartrate in continuous twin-screw melt granulation.

    PubMed

    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. PMID:27452420

  2. Effect of diffusion layer pH and solubility on the dissolution rate of pharmaceutical acids and their sodium salts. II: Salicylic acid, theophylline, and benzoic acid.

    PubMed

    Serajuddin, A T; Jarowski, C I

    1985-02-01

    The pH-solubility profiles of salicylic acid and theophylline, as determined by the addition of HCl or NaOH to their aqueous suspensions, were identical with those of their sodium salts except during phase transitions from acid to salt or vice versa. Supersaturated solutions were formed during phase transitions. Unlike the solubility profiles, the pH-intrinsic dissolution rate profiles of an acid and its salt differed greatly. Good conformity with the Noyes-Whitney equation was demonstrated when the solubility values under pH conditions as the diffusion layer thickness, h, approaches zero (Cs,h = 0) were used rather than solubilities under pH conditions of the bulk media (Cs). The pH when h approaches zero (pHh = 0) was estimated by equilibration of a dissolution medium with an excess of material. Good correlation was shown between the pHh = 0 values of benzoic acid estimated according to this method and the pHh = 0 values reported in the literature. The intrinsic dissolution rate constant, the ratio of the diffusion coefficient to the diffusion layer thickness (D/h), may be assumed constant when comparing the dissolution rates of salicylic acid, theophylline and sodium theophylline. On the other hand, D/h decreased significantly during dissolution of sodium salicylate due to a large increase in Cs,h = 0 and the consequent increase in viscosity in the diffusion layer. A simple method of predicting the dissolution rate of an acid or a salt at different pH values has been developed.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. The Solubility of Xenon in Simple Organic Solvents and in Aqueous Amino Acid Solutions.

    NASA Astrophysics Data System (ADS)

    Himm, Jeffrey Frank

    We have measured the Ostwald solubility (L) of ('133)Xe in a variety of liquids, including normal alkanes, normal alkanols, and aqueous solutions of amino acids, NaCl, and sucrose. For the alkanes and alkanols, measurements were made in the temperature range from 10-50(DEGREES)C. Values of L were found to decrease with increasing temperature, and also with increasing chain length, for both series of solvents. Thermodynamic properties of solution (enthalpy and entropy of solution) are calculated using both mole fraction and number density scales. Results are interpreted using Uhlig's model of the solvation process. Measurements of L in aqueous amino acid solutions were made at 25(DEGREES)C. Concentrations of amino acids in solution varied from near saturation for each of the amino acids studied to pure water. In all solutions, except those with NaCl, L decreases linearly with increasing solution molarity. Hydration numbers (H), the mean number of water molecules associated with each solute molecule, were determined for each amino acid, for NaCl, and for sucrose. Values of H obtained ranged from near zero (arginine, H = 0.2 (+OR-) 0.5) to about 16 (NaCl, H = 16.25 (+OR-) 0.3).

  5. Spectrophotometric determination of uric acid and some redeterminations of its solubility

    USGS Publications Warehouse

    Norton, D.R.; Plunkett, M.A.; Richards, F.A.

    1954-01-01

    The present study was initiated in order to develop a rapid and accurate method for the determination of uric acid in fresh, brackish, and sea water. It was found that the spectrophotometric determination of uric acid based upon its reaction with arsenophosphotungstic acid reagent in the presence of cyanide ion meets this objective. The absorbancy of the blue complex was measured at 890 m??. Slight variations from Beer's law were generally found. The results show the effects of pH, reaction time, concentration of reagents, and temperature upon color development and precipitate formation. Disodium dihydrogen ethylenediamine tetraacetate (Versene) was used as a buffering and complexirig agent. The results are significant in that they give the absorption spectrum of the blue complex and the effects of variables upon its absorbancy. Studies were made with the method to determine the stability of reagents and standard solutions and to determine the rate of bacterial decomposition of uric acid. Measurements of the solubility of uric acid are reported.

  6. Regulation of water-soluble phenolic acid biosynthesis in Salvia miltiorrhiza Bunge.

    PubMed

    Ma, Pengda; Liu, Jingling; Zhang, Chenlu; Liang, Zongsuo

    2013-07-01

    Salvia miltiorrhiza Bunge (Lamiaceae) root, generally called Danshen, is an important herb in Chinese medicine widely used for treatment of various diseases. Phenolic acids in S. miltiorrhiza, as important effective compounds, have become a new research focus in plant secondary metabolism in recent years. This review summarizes the recent advances in the regulation of water-soluble phenolic acid biosynthesis in S. miltiorrhiza via regulators at molecular level, such as the phenylalanine ammonia-lyase gene (PAL), cinnamic acid 4-hydroxylase gene (C4H), 4-coumarate-CoA ligase gene (4CL), tyrosine aminotransferase gene (TAT), 4-hydroxyphenylpyruvate reductase gene (HPPR), 4-hydroxyphenylpyruvated dioxygenase gene (HPPD), hydroxycinnamoyl-CoA:hydroxyphenyllactate hydroxycinnamoyl transferase-like gene (RAS-like), and v-myb avian myeloblastosis viral oncogene homolog 4 gene (MYB4), and production of anthocyanin pigmentation 1 gene (AtPAP1), and via regulators at cell level, such as methyl jasmonate, salicylic acid, abscisic acid, polyamines, metal ions, hydrogen peroxide (H₂O₂), ultraviolet-B radiation, and yeast elicitor.

  7. Effects of excess pantothenic acid administration on the other water-soluble vitamin metabolisms in rats.

    PubMed

    Shibata, Katsumi; Takahashi, Chisato; Fukuwatari, Tsutomu; Sasaki, Ryuzo

    2005-12-01

    To acquire the data concerning the tolerable upper intake level which prevents health problems from an excessive intake of pantothenic acid, an animal experiment was done. Rats of the Wistar strain (male, 3 wk old) were fed on a diet which contains 0%, 0.0016% (control group), 1%, or 3% calcium pantothenate for 29 d. The amount of weight increase, the food intake, and the organ weights were measured, as well as the pantothenic acid contents in urine, the liver and blood. Moreover, to learn the influence of excessive pantothenic acid on other water-soluble vitamin metabolism, thiamin, riboflavin, a vitamin B6 catabolite, the niacin catabolites, and ascorbic acid in urine were measured. As for the 3% addition group, enlargement of the testis, diarrhea, and hair damage were observed, and the amount of weight increase and the food intake were less than those of the control group. However, abnormality was not seen in the 1% addition group. The amount of pantothenic acid in urine, the liver, and blood showed a high correlation with intake level of pantothenic acid. It was only for 4-pyridoxic acid, a vitamin B6 catabolite, in urine that a remarkable difference was observed against the control group. Moreover, the (2-Py+4-Py)/MNA excretion ratio for these metabolites of the nicotinamide also indicated a low value in the 3% pantothenic acid group. As for the calcium pantothenate, it was found that the 3% level in the diet was the lowest-observed-adverse-effect-level (LOAEL) and the 1% level was the no-observed-adverse-effect-level (NOAEL). PMID:16521696

  8. Solubility-pH profiles of some acidic, basic and amphoteric drugs.

    PubMed

    Shoghi, Elham; Fuguet, Elisabet; Bosch, Elisabeth; Ràfols, Clara

    2013-01-23

    The solubility vs. pH profiles of five ionizable drugs of different nature (a monoprotic acid, a monoprotic base, a diprotic base and two amphoteric compounds showing a zwitterionic species each one) have been determined through two different methodologies: the classical shake-flask (S-F) and the potentiometric Cheqsol methods using in both instances the appropriate Henderson-Hasselbalch (H-H) or derived relationships. The results obtained independently from both approaches are consistent. A critical revision about the influence of the electrolyte used as buffering agent in the S-F method on the obtained solubility values is also performed. Thus, some deviations of the experimental points with respect the H-H profiles can be attributed to specific interactions between the buffering electrolyte and the drug due to the hydrotrophic character of citric and lactic acids. In other cases, the observed deviations are independent of the buffers used since they are caused by the formation of new species such as drug aggregates (cefadroxil) or the precipitation of a salt from a cationic species of the analyzed compound (quetiapine).

  9. Artemether-Soluplus Hot-Melt Extrudate Solid Dispersion Systems for Solubility and Dissolution Rate Enhancement with Amorphous State Characteristics

    PubMed Central

    Fule, Ritesh A.; Meer, Tarique S.; Sav, Ajay R.; Amin, Purnima D.

    2013-01-01

    This work studied artemether (ARTM) solid dispersion (SD) formulation using mixture of polymer excipient Soluplus, PEG 400, Lutrol F127, and Lutrol F68 melts at temperatures lower than the melting point of ARTM using a laboratory-size, single-screw rotating batch extruder. The effects of three surfactants PEG 400, Lutrol F127, and Lutrol F68 and parameters like mixing temperature, screw rotating speed, and residence time were systematically studied. SEM, XRD, and FT-IR were employed to investigate the evolution of ARTM's dissolution into the molten excipient. Differential scanning calorimetry (DSC) was used to quantitatively study the melting enthalpy evolution of the drug. The results showed that the dissolution rate increased with increasing the ratio of polymer and surfactant to that of drug. It was concluded that the dissolution of the drug in the polymer melt is a convective diffusion process and that laminar distributive mixing can significantly enhance the dissolution rate. The aqueous solubility and dissolution rate of prepared solid dispersion were significantly enhanced. In vitro antimalarial studies revealed marked improvement in IC50 values. Thus hot-melt extrusion (HME) is a promising technology for improving solubility and dissolution profile of ARTM. PMID:26555968

  10. Characterization and physical stability of tolfenamic acid-PVP K30 solid dispersions.

    PubMed

    Thybo, Pia; Kristensen, Jakob; Hovgaard, Lars

    2007-01-01

    Obtaining a stable formulation with high bioavailability of a poorly water-soluble drug often presents a challenge to the formulation scientist. Transformation of the drug into its more soluble high-energy amorphous form is one method used for improving the dissolution rate of such compounds. The present study uses the spray-drying technique for preparation of solid dispersions (SDs) of tolfenamic acid (TA) and polyvinylpyrrolidone K-30 (PVP). The SDs and TA in the form of a spray-dried powder were initially characterized and compared with a physical mixture and starting materials. Stability of the SDs was monitored over 12 weeks at 25 degrees C and 60% RH. XRPD studies revealed changes in solid state during the formation of the SDs and indicated the presence of TA in the amorphous state. FTIR, together with TGA, suggested molecular interactions (hydrogen-bonding) in the SDs. Dissolution studies proved an increase in the dissolution rate of TA from all SDs. The SDs with higher content of PVP retained TA in the amorphous state throughout the stability study. However, SDs with lower content showed recrystallization of TA after 1 week. Thus, this study reveals the possibility of preparing stable SDs of amorphous TA in PVP with improved dissolution rate.

  11. Mineral species control of aluminum solubility in sulfate-rich acidic waters

    NASA Astrophysics Data System (ADS)

    Jones, Adele M.; Collins, Richard N.; Waite, T. David

    2011-02-01

    The identification of the mineral species controlling the solubility of Al in acidic waters rich in sulfate has presented researchers with several challenges. One of the particular challenges is that the mineral species may be amorphous by X-ray diffraction. The difficulty in discerning between adsorbed or structural sulfate is a further complication. Numerous studies have employed theoretical calculations to determine the Al mineral species forming in acid sulfate soil environments. The vast majority of these studies indicate the formation of a mineral species matching the stoichiometry of jurbanite, Al(OH)SO 4·5H 2O. Much debate, however, exists as to the reality of jurbanite forming in natural environments, particularly in view of its apparent rare occurrence. In this work the use of Al, S and O K-edge XANES spectroscopy, in combination with elemental composition analyses of groundwater precipitates and a theoretical analysis of soluble Al concentrations ranging from pH 3.5 to 7, were employed to determine the mineral species controlling the solubility of Al draining from acid sulfate soils into Blacks Drain in north-eastern New South Wales, Australia. The results indicate that a mixture of amorphous Al hydroxide (Al(OH) 3) and basaluminite (Al 4(SO 4)(OH) 10·5H 2O) was forming. The use of XANES spectroscopy is particularly useful as it provides insight into the nature of the bond between sulfate and Al, and confirms the presence of basaluminite. This counters the possibility that an Al hydroxide species, with appreciable amounts of adsorbed sulfate, is forming within these groundwaters. Below approximately pH 4.5, prior to precipitation of this amorphous Al(OH) 3/basaluminite mixture, our studies indicate that the Al 3+ activity of these acidic sulfate-rich waters is limited by the availability of dissolved Al from exchangeable and amorphous/poorly crystalline mineral species within adjacent soils. Further evidence suggests the Al 3+ activity below pH 4.5 is

  12. Development and characterisation of sustained release solid dispersion oral tablets containing the poorly water soluble drug disulfiram.

    PubMed

    Shergill, Mandip; Patel, Mina; Khan, Siraj; Bashir, Ayesha; McConville, Christopher

    2016-01-30

    Administration of drugs via the oral route is the most common and preferred route due to its ease of administration, cost-effectiveness and flexibility in design. However, if the drug being administered has limited aqueous solubility it can result in poor bioavailability. Furthermore, the low pH of the stomach as well as enzymatic activity can result in drugs delivered via the oral route being rapidly metabolised and degraded. Here we demonstrate the development and characterisation of sustained release solid dispersion oral tablets, containing the poorly water-soluble drug disulfiram (DSF). The tablets, which are manufactured from two different polymers (Kolliphor(®) P 188 and P 237) specifically designed for the manufacture of solid dispersions and two different polymers (Kollidon(®) SR and HPMC) specifically designed to provide sustained release, can enhance the solubility of DSF, sustain its release, while protecting it from degradation in simulated gastric fluid (SGF). The paper demonstrates that when using the hot melt method at 80°C the DSF loading capacity of the Kolliphor(®) P 188 and P 237 polymers is approximately 43 and 46% respectively, with the DSF completely in an amorphous state. The addition of 80% Kollidon(®) SR to the formulation completely protected the DSF in SGF for up to 70 min with 16% degradation after 120 min, while 75% degradation occurred after 120 min with the addition of 80% HPMC. The release rate of DSF can be manipulated by both the loading and type of sustained release polymer used, with HPMC providing for a much faster release rate compared to Kollidon(®) SR.

  13. Development and characterisation of sustained release solid dispersion oral tablets containing the poorly water soluble drug disulfiram.

    PubMed

    Shergill, Mandip; Patel, Mina; Khan, Siraj; Bashir, Ayesha; McConville, Christopher

    2016-01-30

    Administration of drugs via the oral route is the most common and preferred route due to its ease of administration, cost-effectiveness and flexibility in design. However, if the drug being administered has limited aqueous solubility it can result in poor bioavailability. Furthermore, the low pH of the stomach as well as enzymatic activity can result in drugs delivered via the oral route being rapidly metabolised and degraded. Here we demonstrate the development and characterisation of sustained release solid dispersion oral tablets, containing the poorly water-soluble drug disulfiram (DSF). The tablets, which are manufactured from two different polymers (Kolliphor(®) P 188 and P 237) specifically designed for the manufacture of solid dispersions and two different polymers (Kollidon(®) SR and HPMC) specifically designed to provide sustained release, can enhance the solubility of DSF, sustain its release, while protecting it from degradation in simulated gastric fluid (SGF). The paper demonstrates that when using the hot melt method at 80°C the DSF loading capacity of the Kolliphor(®) P 188 and P 237 polymers is approximately 43 and 46% respectively, with the DSF completely in an amorphous state. The addition of 80% Kollidon(®) SR to the formulation completely protected the DSF in SGF for up to 70 min with 16% degradation after 120 min, while 75% degradation occurred after 120 min with the addition of 80% HPMC. The release rate of DSF can be manipulated by both the loading and type of sustained release polymer used, with HPMC providing for a much faster release rate compared to Kollidon(®) SR. PMID:26608620

  14. Solid-state characterization and solubility of a genistein-caffeine cocrystal

    NASA Astrophysics Data System (ADS)

    Sowa, Michał; Ślepokura, Katarzyna; Matczak-Jon, Ewa

    2014-11-01

    Combination of genistein and caffeine leads to a 1:1 cocrystalline phase, which was identified by means of a solvent-drop grinding experiment and isolated afterwards in a solution-evaporation approach. Obtained cocrystal was characterized by X-ray single-crystal and powder diffraction as well as investigated in terms of thermal stability and Hirshfeld surfaces. A scale-up procedure was provided by slurry technique, enabling solubility determination. Neutral forms of both compounds cocrystallize in a common P21/c space group of the monoclinic crystal system. Analysis of packing and interactions in the crystal lattice reveals formation of molecular layers, formed by O-H⋯O, O-H⋯N and C-H⋯O-type contacts between genistein and caffeine molecules, whereas stabilization of the three-dimensional crystal lattice is provided by π⋯π interactions. Dissolution studies in a 50:50 v/v ethanol-water medium revealed that the maximum solubility of the cocrystalline phase reached 0.861 mg/mL after 8 h, revealing some degree of enhancement as compared to parent genistein, maximum solubility of which was also reached after 8 h and equalled 0.588 mg/mL.

  15. Solid phase sequencing of double-stranded nucleic acids

    DOEpatents

    Fu, Dong-Jing; Cantor, Charles R.; Koster, Hubert; Smith, Cassandra L.

    2002-01-01

    This invention relates to methods for detecting and sequencing of target double-stranded nucleic acid sequences, to nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probe comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Nucleic acids whose sequences can be determined include nucleic acids in biological samples such as patient biopsies and environmental samples. Probes may be fixed to a solid support such as a hybridization chip to facilitate automated determination of molecular weights and identification of the target sequence.

  16. Water Soluble Usnic Acid-Polyacrylamide Complexes with Enhanced Antimicrobial Activity against Staphylococcus epidermidis

    PubMed Central

    Francolini, Iolanda; Taresco, Vincenzo; Crisante, Fernanda; Martinelli, Andrea; D’Ilario, Lucio; Piozzi, Antonella

    2013-01-01

    Usnic acid, a potent antimicrobial and anticancer agent, poorly soluble in water, was complexed to novel antimicrobial polyacrylamides by establishment of strong acidic-base interactions. Thermal and spectroscopic analysis evidenced a molecular dispersion of the drug in the polymers and a complete drug/polymer miscibility for all the tested compositions. The polymer/drug complexes promptly dissolved in water and possessed a greater antimicrobial activity against Staphylococcus epidermidis than both the free drug and the polymer alone. The best results were obtained with the complex based on the lowest molecular weight polymer and containing a low drug content. Such a complex showed a larger inhibition zone of bacterial growth and a lower minimum inhibitory concentration (MIC) with respect to usnic acid alone. This improved killing effect is presumably due to the reduced size of the complexes that allows an efficient cellular uptake of the antimicrobial complexes. The killing effect extent seems to be not significantly dependent on usnic acid content in the samples. PMID:23549269

  17. Conversion of biomass into 5-hydroxymethylfurfural using solid acid catalyst.

    PubMed

    Yang, Fengli; Liu, Qishun; Bai, Xuefang; Du, Yuguang

    2011-02-01

    5-Hydroxymethylfurfural (HMF) was produced from monosaccharide (fructose and glucose), polysaccharide (inulin) and the Jerusalem artichoke juice by a simple one-pot reaction including hydrolysis and dehydration using solid acid under mild condition. Hydrated niobium pentoxide (Nb(2)O(5)·nH(2)O(2)) after pretreatment showed high catalytic activities for dehydration of mono- and polysaccharide to HMF at 433 K in water-2-butanol (2:3 v/v) biphasic system, giving high HMF yield of 89% and 54% from fructose and inulin, respectively. The HMF yield was up to 74% and 65% when inulin and Jerusalem artichoke juice were hydrolyzed by exoinulinase. The solid acid made the process environment-friendly and energy-efficient to convert carbohydrates into bio-fuels and platform chemicals. PMID:21036606

  18. [Effects of exogenous nitric oxide, salicylic acid and hydrogen peroxide on free amino acid and soluble protein contents in tobacco leaves].

    PubMed

    Wei, Xiao-Hong; Wang, Li-Min; Long, Rui-Jun; Wang, Gen-Xuan

    2006-04-01

    The work focused on the effects of signal molecules of nitric oxide (NO), salicylic acid (SA) and hydrogen peroxide (H(2)O(2)) on compounds of nitric metabolites of free amino acid, soluble protein and proline in tobacco. The results indicated that NO, SA and H(2)O(2) were able to regulate the proline, free amino acid and soluble protein content in tobacco. Lower concentration of NO and H(2)O(2) raised the level of proline; while higher concentration of NO and H(2)O(2) lowered the proline, free amino acid content in tobacco. The above three signal molecules also showed similar effects on proline, free amino acid and soluble protein content in tobacco.

  19. Plant-available and water-soluble phosphorus in soils amended with separated manure solids.

    PubMed

    Gasser, M-O; Chantigny, M H; Angers, D A; Bittman, S; Buckley, K E; Rochette, P; Massé, D

    2012-01-01

    Physical, chemical, or biological treatment of animal liquid manure generally produces a dry-matter rich fraction (DMF) that contains most of the initial phosphorus (P). Our objective was to assess the solubility and plant availability of P from various DMFs as a function of soil P status. Eight different DMFs were obtained from liquid swine (LSM) and dairy cattle (LDC) manures treated by natural decantation, anaerobic digestion, chemical flocculation, composting, or mechanical separation. The DMFs were compared with mineral P fertilizer in a pot experiment with oat ( L.) grown in four soils with varied P-fixing capacities and P saturation levels. The DMFs were added at a rate of 50 mg P kg soil and incubated 14 d before seeding. Soil water-extractable P (P) at all water:soil extraction ratios (2:1, 20:1, and 200:1) was slightly higher when DMFs were derived from LDC rather than LSM. Soil P at the 2:1 ratio was lower with anaerobically digested LSM. At the 2:1 extraction ratio, DMF P was less soluble than mineral P as P saturation in soils increased. In soils with a lower P-fixing capacity, DMF P appeared less water soluble than mineral P under 20:1 and 200:1 extraction ratios. After 72 d of plant growth, DMFs produced yields comparable to mineral P fertilizer. Although the plant availability of P from DMFs was comparable to mineral P fertilizer, P from DMFs could be less vulnerable to leaching or runoff losses in soils with a high P saturation level or low P-fixing capacity.

  20. A chemical test of the principle of critical point universality: The solubility of nickel (II) oxide in isobutyric acid + water near the consolute point

    NASA Astrophysics Data System (ADS)

    Hu, Baichuan; Baird, James K.; Richey, Randi D.; Reddy, Ramana G.

    2011-04-01

    A mixture of isobutyric acid + water has an upper consolute point at 38.8 mass % isobutyric acid and temperature near 26 °C. Nickel (II) oxide dissolves in this mixture by reacting with the acid to produce water and nickel isobutyrate. The solubility of nickel (II) oxide in isobutyric acid + water has been measured as a function of temperature at compositions, 25, 38.8, and 60 mass % isobutyric acid. For values of the temperature, T, which were at least 2 K in excess of the liquid-liquid phase transition temperature, the measured values of the solubility, s, lie on a straight line when plotted in van't Hoff form with ln s versus 1/T. The slope, (∂ln s/∂(1/T)), of the line is negative indicating that the dissolution reaction is endothermic. When the temperature was within 2 K of the phase transition temperature, however, (∂ln s/∂(1/T)) diverged toward negative infinity. The principle of critical point universality predicts that when excess solid nickel (II) oxide is in dissolution equilibrium with liquid isobutyric acid + water, (∂ln s/∂(1/T)) should diverge upon approaching the consolute point along the critical isopleth at 38.8 mass % isobutyric acid. As determined by the sign of the enthalpy of solution, the sign of this divergence is expected to be negative. Not only do our experiments confirm these predictions, but they also show that identical behavior can be observed at both 25 and 60 mass % isobustyric acid, compositions which lie substantially to either side of the critical composition.

  1. Structural diversity of solid dispersions of acetylsalicylic acid as seen by solid-state NMR.

    PubMed

    Policianova, Olivia; Brus, Jiri; Hruby, Martin; Urbanova, Martina; Zhigunov, Alexander; Kredatusova, Jana; Kobera, Libor

    2014-02-01

    Solid dispersions of active pharmaceutical ingredients are of increasing interest due to their versatile use. In the present study polyvinylpyrrolidone (PVP), poly[N-(2-hydroxypropyl)-metacrylamide] (pHPMA), poly(2-ethyl-2-oxazoline) (PEOx), and polyethylene glycol (PEG), each in three Mw, were used to demonstrate structural diversity of solid dispersions. Acetylsalicylic acid (ASA) was used as a model drug. Four distinct types of the solid dispersions of ASA were created using a freeze-drying method: (i) crystalline solid dispersions containing nanocrystalline ASA in a crystalline PEG matrix; (ii) amorphous glass suspensions with large ASA crystallites embedded in amorphous pHPMA; (iii) solid solutions with molecularly dispersed ASA in rigid amorphous PVP; and (iv) nanoheterogeneous solid solutions/suspensions containing nanosized ASA clusters dispersed in a semiflexible matrix of PEOx. The obtained structural data confirmed that the type of solid dispersion can be primarily controlled by the chemical constitutions of the applied polymers, while the molecular weight of the polymers had no detectable impact. The molecular structure of the prepared dispersions was characterized using solid-state NMR, wide-angle X-ray scattering (WAXS), and differential scanning calorimetry (DSC). By applying various (1)H-(13)C and (1)H-(1)H correlation experiments combined with T1((1)H) and T1ρ((1)H) relaxation data, the extent of the molecular mixing was determined over a wide range of distances, from intimate intermolecular contacts (0.1-0.5 nm) up to the phase-separated nanodomains reaching ca. 500 nm. Hydrogen-bond interactions between ASA and polymers were probed by the analysis of (13)C and (15)N CP/MAS NMR spectra combined with the measurements of (1)H-(15)N dipolar profiles. Overall potentialities and limitations of individual experimental techniques were thoroughly evaluated.

  2. Phenobarbital induction of a soluble cytochrome P-450-dependent fatty acid monooxygenase in Bacillus megaterium.

    PubMed

    Narhi, L O; Fulco, A J

    1982-03-10

    A soluble, cytochrome P-450-dependent fatty acid hydroxylase-epoxidase isolated from Bacillus megaterium ATCC 14581 can be induced about 28-fold by the addition of phenobarbital (8 mM) to the growth medium. Phenobarbital is not a substrate for the enzyme nor does it activate the monooxygenase in the cell-free system. The level of the P-450-dependent monooxygenase activity in cultures harvested during the early stationary phase of growth increased linearly with phenobarbital concentration up to its solubility limit (8 mM) at 35 degrees C. The time course of induction during culture growth in the presence of 4 mM phenobarbital showed an interesting dichotomy. The specific content of cytochrome P-450 increased until the early stationary phase of growth and then leveled off. P-450-dependent monooxygenase activity, however, continued to increase rapidly to midstationary phase and then decreased just as rapidly after this time. At maximum specific activity, a turnover number of about 2,450 was obtained for palmitoleate hydroxylation-epoxidation by the cytochrome P-450 system. PMID:6801029

  3. Isolation and characterization of acid-soluble collagen from the scales of marine fishes from Japan and Vietnam.

    PubMed

    Minh Thuy, Le Thi; Okazaki, Emiko; Osako, Kazufumi

    2014-04-15

    Acid-soluble collagen (ASC) was successfully extracted from the scales of lizard fish (Saurida spp.) and horse mackerel (Trachurus japonicus) from Japan and Vietnam and grey mullet (Mugil cephalis), flying fish (Cypselurus melanurus) and yellowback seabream (Dentex tumifrons) from Japan. ASC yields were about 0.43-1.5% (on a dry weight basis), depending on the species. The SDS-PAGE profile showed that the ASCs were type I collagens, and consisted of two different α chains, α1 and α2, as well as a β component. ASC of horse mackerel from Vietnam contained a higher imino acid level than that from Japan. ASC denaturation temperature (Td) ranged from 26 to 29 °C, depending on fish species and imino acid content (p<0.01). Maximal solubility of individual collagens was observed at pHs 1-3. Collagen solubility decreased sharply at NaCl concentrations >0.4M, regardless of fish type.

  4. Isolation and characterization of acid-soluble collagen from the scales of marine fishes from Japan and Vietnam.

    PubMed

    Minh Thuy, Le Thi; Okazaki, Emiko; Osako, Kazufumi

    2014-04-15

    Acid-soluble collagen (ASC) was successfully extracted from the scales of lizard fish (Saurida spp.) and horse mackerel (Trachurus japonicus) from Japan and Vietnam and grey mullet (Mugil cephalis), flying fish (Cypselurus melanurus) and yellowback seabream (Dentex tumifrons) from Japan. ASC yields were about 0.43-1.5% (on a dry weight basis), depending on the species. The SDS-PAGE profile showed that the ASCs were type I collagens, and consisted of two different α chains, α1 and α2, as well as a β component. ASC of horse mackerel from Vietnam contained a higher imino acid level than that from Japan. ASC denaturation temperature (Td) ranged from 26 to 29 °C, depending on fish species and imino acid content (p<0.01). Maximal solubility of individual collagens was observed at pHs 1-3. Collagen solubility decreased sharply at NaCl concentrations >0.4M, regardless of fish type. PMID:24295705

  5. Recovery of soluble chloride salts from the wastewater generated during the washing process of municipal solid wastes incineration fly ash.

    PubMed

    Tang, Hailong; Erzat, Aris; Liu, Yangsheng

    2014-01-01

    Water washing is widely used as the pretreatment method to treat municipal solid waste incineration fly ash, which facilitates the further solidification/stabilization treatment or resource recovery of the fly ash. The wastewater generated during the washing process is a kind of hydrosaline solution, usually containing high concentrations of alkali chlorides and sulphates, which cause serious pollution to environment. However, these salts can be recycled as resources instead of discharge. This paper explored an effective and practical recovery method to separate sodium chloride, potassium chloride, and calcium chloride salts individually from the hydrosaline water. In laboratory experiments, a simulating hydrosaline solution was prepared according to composition of the waste washing water. First, in the three-step evaporation-crystallization process, pure sodium chloride and solid mixture of sodium and potassium chlorides were obtained separately, and the remaining solution contained potassium and calcium chlorides (solution A). And then, the solid mixture was fully dissolved into water (solution B obtained). Finally, ethanol was added into solutions A and B to change the solubility of sodium, potassium, and calcium chlorides within the mixed solvent of water and ethanol. During the ethanol-adding precipitation process, each salt was separated individually, and the purity of the raw production in laboratory experiments reached about 90%. The ethanol can be recycled by distillation and reused as the solvent. Therefore, this technology may bring both environmental and economic benefits.

  6. Recovery of soluble chloride salts from the wastewater generated during the washing process of municipal solid wastes incineration fly ash.

    PubMed

    Tang, Hailong; Erzat, Aris; Liu, Yangsheng

    2014-01-01

    Water washing is widely used as the pretreatment method to treat municipal solid waste incineration fly ash, which facilitates the further solidification/stabilization treatment or resource recovery of the fly ash. The wastewater generated during the washing process is a kind of hydrosaline solution, usually containing high concentrations of alkali chlorides and sulphates, which cause serious pollution to environment. However, these salts can be recycled as resources instead of discharge. This paper explored an effective and practical recovery method to separate sodium chloride, potassium chloride, and calcium chloride salts individually from the hydrosaline water. In laboratory experiments, a simulating hydrosaline solution was prepared according to composition of the waste washing water. First, in the three-step evaporation-crystallization process, pure sodium chloride and solid mixture of sodium and potassium chlorides were obtained separately, and the remaining solution contained potassium and calcium chlorides (solution A). And then, the solid mixture was fully dissolved into water (solution B obtained). Finally, ethanol was added into solutions A and B to change the solubility of sodium, potassium, and calcium chlorides within the mixed solvent of water and ethanol. During the ethanol-adding precipitation process, each salt was separated individually, and the purity of the raw production in laboratory experiments reached about 90%. The ethanol can be recycled by distillation and reused as the solvent. Therefore, this technology may bring both environmental and economic benefits. PMID:25176491

  7. Modulation of microenvironmental pH and utilization of alkalizers in crystalline solid dispersion for enhanced solubility and stability of clarithromicin.

    PubMed

    Park, Jun-Bom; Park, Young-Joon; Kang, Chin-Yang; Lee, Beom-Jin

    2015-01-01

    Clarithromycin (CAM) is known to be poorly water-soluble and acid-labile drug. Various alkalizers such as MgO, Na2CO3, Na2HPO4 and NaHCO3 were utilized to modulate the microenvironmental pH (pHM) and to improve the low stability and solubility of CAM in a crystalline-solid dispersion system (CSD). Polyvinylpyrrolidone (PVP K-30) and hydroxypropylmethylcellulose (HPMC) 4000-based CSDs containing alkalizers were prepared by cosolvent precipitation followed by evaporation process. The dried-CSDs mixed with microcrystalline cellulose, 2% croscarmellose sodium, and 1% magnesium stearate was then directly compressed into tablet. A dissolution test was carried out in 900 mL of pH 5.0 buffer solutions at 37 °C with a 50 rpm paddle speed. pHM, surface morphology, and structural behaviors were investigated. The dissolution rates of CAM in CSD containing alkalizers were improved. The drug in CSD remained crystalline as observed by differential scanning calorimetry and powder X-ray diffraction. Scanning electron microscopy revealed nearly identical images regardless of the sorts and amounts of carriers. PVP-based CSD tablet without alkalizer showed greater drug release, while HPMC-based CSD tablet without alkalizer retarded drug release due to its greater swelling capability. However, when the alkalizers were added in CSD tablet, the drug release was sharply increased. NaHCO3 induced the most rapid drug release while MgO retarded drug dissolution. Alkalizers in CSD also could maintain the pHM of the tablet above pH 5 under acidic conditions. The use of pH modifiers in CSDs could provide a useful method to improve the dissolution rate and stability of CAM via modulation of pHM without changing drug crystallinity.

  8. Pharmacokinetics of salicylic acid following administration of aspirin tablets and three different forms of soluble aspirin in normal subjects.

    PubMed

    Gatti, G; Barzaghi, N; Attardo Parrinello, G; Vitiello, B; Perucca, E

    1989-01-01

    The pharmacokinetic profile of an innovative formulation of soluble aspirin (l-ornithine acetylsalicylate, ldB 1003) was compared with that of conventional tablets and two other soluble dosage forms (d, l-lysine acetylsalicylate and a buffered effervescent formulation of acetylsalicylic acid) after administration of single oral doses in six normal volunteers. All soluble forms showed a rapid absorption profile, peak plasma salicylic acid levels being attained after about 30 min on average and without statistically significant differences among the solutions tested. As compared to the soluble formulations, acetylsalicylic acid given as tablets resulted in slower absorption, with peak plasma salicylic acid levels being reached more than 1 h after dosing. Despite these differences in time course of plasma level profiles, the extent of absorption was similar for all formulations. Apart from the potential advantages in terms of improved gastric tolerability, the increased rate of absorption of aspirin solutions is therapeutically useful whenever a rapid onset of action is required. In this respect, the kinetic pattern of the innovative formulation compares favourably with that of other available soluble dosage forms.

  9. Pharmacokinetics of salicylic acid following administration of aspirin tablets and three different forms of soluble aspirin in normal subjects.

    PubMed

    Gatti, G; Barzaghi, N; Attardo Parrinello, G; Vitiello, B; Perucca, E

    1989-01-01

    The pharmacokinetic profile of an innovative formulation of soluble aspirin (l-ornithine acetylsalicylate, ldB 1003) was compared with that of conventional tablets and two other soluble dosage forms (d, l-lysine acetylsalicylate and a buffered effervescent formulation of acetylsalicylic acid) after administration of single oral doses in six normal volunteers. All soluble forms showed a rapid absorption profile, peak plasma salicylic acid levels being attained after about 30 min on average and without statistically significant differences among the solutions tested. As compared to the soluble formulations, acetylsalicylic acid given as tablets resulted in slower absorption, with peak plasma salicylic acid levels being reached more than 1 h after dosing. Despite these differences in time course of plasma level profiles, the extent of absorption was similar for all formulations. Apart from the potential advantages in terms of improved gastric tolerability, the increased rate of absorption of aspirin solutions is therapeutically useful whenever a rapid onset of action is required. In this respect, the kinetic pattern of the innovative formulation compares favourably with that of other available soluble dosage forms. PMID:2517497

  10. The entry of HCl through soluble surfactants on sulfuric acid: effects of chain branching.

    PubMed

    Burden, Daniel K; Johnson, Alexis M; Krier, James M; Nathanson, Gilbert M

    2014-07-17

    Gas-liquid scattering experiments are used to determine how a soluble, branched surfactant (2-ethylbutanol) controls the entry of gaseous HCl molecules into 60 and 68 wt % D2SO4 at 213 K. Short-chain alcohols spontaneously segregate to the surfaces of these sulfuric acid solutions, which are representative of aerosol droplets in the lower stratosphere. We find that 2-ethylbutanol enhances HCl entry at low surface coverages, most likely because it provides extra interfacial OH groups that aid HCl dissociation. This enhancement disappears at higher coverages as the alkyl chains crowd each other and block access to the acid. The branched alcohol impedes HCl entry more effectively than its unbranched isomer 1-hexanol, implying that the larger 2-ethybutanol footprint on the surface blocks more HCl molecules from reaching the alcohol-acid interface. This behavior contrasts sharply with gas transport through long-chain monolayers, where branching introduces gaps that allow more facile passage. The experiments suggest that short-chain surfactants with extended footprints may impede transport more effectively than their unbranched isomers. PMID:24620717

  11. PEGylated bile acids for use in drug delivery systems: enhanced solubility and bioavailability of itraconazole.

    PubMed

    Le Dévédec, Frantz; Strandman, Satu; Hildgen, Patrice; Leclair, Grégoire; Zhu, X X

    2013-08-01

    Itraconazole is a drug of choice for the treatment of severe fungal infections and parasitic diseases, but its use is limited by its low water solubility and varying bioavailability. New self-emulsifying drug delivery systems (SEDDS) based on PEGylated bile acids (BA-PEGs) were designed and prepared, where the number and length of PEG arms were varied to optimize the loading of itraconazole in the final drug formulation. The use of both BA-PEGs and oleic acid improved the solubilization and absorption of the drug, which was in a glassy state in the SEDDS prepared with the melting method. High loading efficiencies of itraconazole (up to 20%) and stable liquid formulations were obtained at neutral pH, and full dispersion of itraconazole was reached in 2 h in simulated intestinal fluid (pH 6.8). Aqueous emulsions consisting of spherical micelles with mean hydrodynamic diameters (Dh) of ca. 75-220 nm, as verified by transmission electron microscopy and dynamic light scattering, are expected to improve the intestinal absorption of the drug. The new SEDDS showed good cytocompatibility by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays of BA-PEGs with Caco-2 and RAW 264.2 cells, and a low degree of hemolysis of human erythrocytes. The SEDDS based on PEGylated bile acids provide a controlled release system with significant improvement of the bioavailability of itraconazole in rats, as demonstrated by the pharmacokinetic studies.

  12. Supercritical Carbon Dioxide-Soluble Ligands for Extracting Actinide Metal Ions from Porous Solids

    SciTech Connect

    Dietz, Mark L.; Barrans Jr., Richard E.; Herlinger, Albert; Brennecke, Joan F.

    1999-06-01

    The focus of the effort during the project period from 9/16/98 to 6/15/99 has been on the synthesis, aggregation, and coordination chemistry of silyl-containing diphosphonic acids that potentially could be useful as solvent extraction reagents in supercritical CO2. A homologous series of alkylenediphosphonic acids was esterified with 3-(trimethylsilyl)-1- propanol to the symmetrically-substituted diesters. The silicon-containing alcohol 3- (trimethylsilyl)-1-propanol was chosen for esterification of the diphosphonic acids because it contains both a silyl group and a trimethylene linker. Separating the trimethylsilyl from the organo-functional group by three carbon atoms is optimal for achieving chemical stability and synthetic accessibility. The synthesis of these compounds utilizes methodology that relies on dicyclohexylcarbodiimide as the esterification reagent to activate the acid.

  13. Determination of acidity constants of sparingly soluble drugs in aqueous solution by the internal standard capillary electrophoresis method.

    PubMed

    Cabot, Joan Marc; Fuguet, Elisabet; Rosés, Martí

    2014-12-01

    A set of 33 drugs with different solubilities, ranging from soluble to very insoluble, has been chosen in order to evaluate the performance of the internal standard CE method to determine acidity constants of compounds with limited solubility. The set of drugs tested in this work has been chosen as a function of their intrinsic solubility. For the most insoluble compounds, several analytical conditions to overcome the insolubility in aqueous buffers have been tested. This paper assesses the compound solubility limits for the IS-CE method in aqueous pKa determinations, and also compares the determined pKa s with the results from the literature data obtained by other methods. It is proved that IS-CE method determines acidity constants of sparingly soluble drugs in aqueous media (compounds with logS down to around -6), whereas other reference methods require the use of aqueous-organic solvent buffers and extrapolation procedures to obtain the aqueous pKa for the same compounds.

  14. Improved bioavailability and antiasthmatic efficacy of poorly soluble curcumin-solid dispersion granules obtained using fluid bed granulation.

    PubMed

    Jang, Dong-Jin; Kim, Sung Tae; Lee, Kooyeon; Oh, Euichaul

    2014-01-01

    The intestinal absorption and antiasthmatic efficacy of poorly water-soluble curcumin (CUR), which has low solubility and permeability, was increased by fabricating solid dispersion granules (SDGs). The SDG containing CUR (SDG-CUR) was prepared by dispersing CUR in excess Cremophor RH40 as a solubilizer and Ryoto sugar ester L-1695 as an absorption enhancer using fluid bed granulation. We evaluated the physicochemical properties such as crystallinity and dissolution, pharmacokinetics, and antiasthmatic efficacy of SDG-CUR. Our results showed that CUR was molecularly dispersed, and the dissolution of SDG-CUR was significantly higher than that of native CUR. In addition, the blood concentration of SDG-CUR in rats was much higher than that of native CUR. Compared to CUR, SDG-CUR showed a 9.1- and 13.1-fold increase in area under the plasma concentration-time curve (AUC) and maximum plasma concentration (Cmax), respectively. Further, SDG-CUR effectively alleviated airway hyperresponsiveness and levels of T-helper 2 cytokines (interleukin-4, interleukin-5, and interleukin-13) in a murine model of asthma. In conclusion, our results suggest that the SDGs could be considered as a potential oral formulation to enhance the absorption and efficacy of CUR.

  15. Solubility prediction of salicylic acid in water-ethanol-propylene glycol mixtures using the Jouyban-Acree model.

    PubMed

    Jouyban, A; Chew, N Y K; Chan, H K; Khoubnasabjafari, M; Acree, W E

    2006-04-01

    To show the applicability of a solution model, i.e. the Jouyban-Acree model, for predicting the solubility of a solute in ternary solvent systems based on model constants computed using solubility data of the solute in binary solvent systems, the solubility of salicylic acid in water-ethanol, water-propylene glycol, ethanol-propylene glycol mixtures was determined. A minimum number of three data points from each binary system was used to calculate the binary interaction parameters of the model. Then the solubility in other binary solvent compositions and also in a number of ternary solvents was predicted, and the mean percentage deviation (MPD) was calculated as an accuracy criterion. The overall MPD (+/-SD) was 7.3 (+/-7.3)% and those of a similar predictive model was 15.7 (+/-11.5)%. The mean difference between the proposed and a previous model was statistically significant (paired t-test, p < 0.004).

  16. Solid Lipid Nanoparticles Loaded with Retinoic Acid and Lauric Acid as an Alternative for Topical Treatment of Acne Vulgaris.

    PubMed

    Silva, Elton Luiz; Carneiro, Guilherme; De Araújo, Lidiane Advíncula; Trindade, Mariana de Jesus Vaz; Yoshida, Maria Irene; Oréfice, Rodrigo Lambert; Farias, Luis de Macêdo; De Carvalho, Maria Auxiliadora Roque; Dos Santos, Simone Gonçalves; Goulart, Gisele Assis Castro; Alves, Ricardo José; Ferreira, Lucas Antônio Miranda

    2015-01-01

    Topical therapy is the first choice for the treatment of mild to moderate acne and all-trans retinoic acid is one of the most used drugs. The combination of retinoids and antimicrobials is an innovative approach for acne therapy. Recently, lauric acid, a saturated fatty acid, has shown strong antimicrobial activity against Propionibacterium acnes. However, topical application of retinoic acid is followed by high incidence of side-effects, including erythema and irritation. Solid lipid nanoparticles represent an alternative to overcome these side-effects. This work aims to develop solid lipid nanoparticles loaded with retinoic acid and lauric acid and evaluate their antibacterial activity. The influence of lipophilic stearylamine on the characteristics of solid lipid nanoparticles was investigated. Solid lipid nanoparticles were characterized for size, zeta potential, encapsulation efficiency, differential scanning calorimetry and X-ray diffraction. The in vitro inhibitory activity of retinoic acid-lauric acid-loaded solid lipid nanoparticles was evaluated against Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis. High encapsulation efficiency was obtained at initial time (94 ± 7% and 100 ± 4% for retinoic acid and lauric acid, respectively) and it was demonstrated that lauric acid-loaded-solid lipid nanoparticles provided the incorporation of retinoic acid. However, the presence of stearylamine is necessary to ensure stability of encapsulation. Moreover, retinoic acid-lauric acid-loaded solid lipid nanoparticles showed growth inhibitory activity against Staphylococcus epidermidis, Propionibacterium acnes and Staphylococcus aureus, representing an interesting alternative for the topical therapy of acne vulgaris. PMID:26328443

  17. Neopentane and solid acids: direct hydron exchange before cracking.

    PubMed

    Walspurger, Stéphane; Sun, Yinyong; Souna Sido, Abdelkarim Sani; Sommer, Jean

    2006-09-21

    The hydrogen/deuterium exchange reaction of 2,2-dimethylpropane (neopentane) over D(2)O-exchanged zeolites (MOR, FAU, BEA, MFI) using a batch recirculation reactor was studied by means of gas chromatography coupled with mass spectrometer. In the temperature range 473-573 K, H/D exchange proceeds without side reaction such as cracking at short contact times. Indeed the C-H bond has appeared favorably involved in the activation of neopentane compared to the less accessible C-C bond. The transition state allowing hydron exchange is most likely a carbonium species (pentacoordinated carbon) as in the case of the H/D exchange between methane and solid acid. The activation energies of the H/D exchange between neopentane and zeolites are the same for all zeolites indicating a common carbonium ion type transition state. On the basis of previous results in the case of the exchange between methane and liquid superacids, the deuterium exchange rates in neopentane were tentatively related to the acidity of the solids. However the order of activity MOR > MFI > BEA > FAU seems to be related to the size of the pores, which may suggest the involvement of a confinement effect in the zeolites cavities. Moreover we found that H/D exchange takes also place between neopentane and deuterated sulfated zirconia (SZ) emphasizing its strong acidity.

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

    PubMed

    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.

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

    PubMed Central

    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 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-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. PMID:24403830

  20. Authentication of dried distilled grain with solubles (DDGS) by fatty acid and volatile profiling

    PubMed Central

    Tres, Alba; Heenan, Samuel P.; van Ruth, Saskia

    2014-01-01

    Demand for ethanol substituted fuels from the utilisation of cereal based biofuel has resulted in an over production of dried distillers grains with solubles (DDGS) that are now readily available on the animal feed market. With this rapid emerging availability comes potential variability in the nutritional value of DDGS and possible risks of feed contaminants. Subsequently, the authentication and traceability of alternative animal feed sources is of high priority. In this study and as part of the EU research project “Quality and Safety of Feeds and Food for Europe (QSAFFE FP7-KBBE-2010-4) an attempt was made to classify the geographical origin of cereal grains used in the production of DDGS material. DDGS material of wheat and corn origin were obtained from Europe, China, and the USA. Fatty acid profiles and volatile fingerprints were assessed by gas chromatography flame ionisation (GC-FID) and rapid proton transfer reaction mass spectrometry (PTR-MS) respectively. Chemometric analysis of fatty acid profiles and volatile fingerprints allowed for promising classifications of cereals used in DDGS material by geographical and botanical origin and enabled visual representation of the data. This objective analytical approach could be adapted for routine verification of cereal grains used in the production of DDGS material. PMID:25368433

  1. Formation and catalytic activity of high molecular weight soluble polymers produced by heating amino acids in a modified sea medium

    NASA Astrophysics Data System (ADS)

    Okihana, Hiroyuki

    1982-06-01

    Eighteen protein amino acids with milk casein composition were heated in a modified sea medium. Marigranules were formed in the precipitates and soluble polymers were formed in the supernatant. Time course of the reaction (ultraviolet spectra, the concentration of metal ions, and the concentration of amino acids in the supernatant) were measured. The time course of the formation of the soluble polymers was also studied by Bio-Gel P-2 column. High molecular weight soluble polymers (HMWSP) were separated from low molecular weight ones by dialysis. It was shown that these polymers catalyzed the dehydrogenation of NADH. These polymers also catalyzed the coupled reaction between dehydrogenation of NADH and reduction of resazurin. This coupled reaction was accelerated by the light.

  2. [Determination of Soluble Solid Content in Strawberry Using Hyperspectral Imaging Combined with Feature Extraction Methods].

    PubMed

    Ding, Xi-bin; Zhang, Chu; Liu, Fei; Song, Xing-lin; Kong, Wen-wen; He, Yong

    2015-04-01

    Hyperspectral imaging combined with feature extraction methods were applied to determine soluble sugar content (SSC) in mature and scatheless strawberry. Hyperspectral images of 154 strawberries covering the spectral range of 874-1,734 nm were captured and the spectral data were extracted from the hyperspectral images, and the spectra of 941~1,612 nm were preprocessed by moving average (MA). Nineteen samples were defined as outliers by the residual method, and the remaining 135 samples were divided into the calibration set (n = 90) and the prediction set (n = 45). Successive projections algorithm (SPA), genetic algorithm partial least squares (GAPLS) combined with SPA, weighted regression coefficient (Bw) and competitive adaptive reweighted sampling (CARS) were applied to select 14, 17, 24 and 25 effective wavelengths, respectively. Principal component analysis (PCA) and wavelet transform (WT) were applied to extract feature information with 20 and 58 features, respectively. PLS models were built based on the full spectra, the effective wavelengths and the features, respectively. All PLS models obtained good results. PLS models using full-spectra and features extracted by WT obtained the best results with correlation coefficient of calibration (r(c)) and correlation coefficient of prediction (r(p)) over 0.9. The overall results indicated that hyperspectral imaging combined with feature extraction methods could be used for detection of SSC in strawberry. PMID:26197594

  3. Vibrational entropy changes the solid solubility of a random alloy at high temperatures

    NASA Astrophysics Data System (ADS)

    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).

  4. Solid solubility and photoluminescence of Y3Al5O12:Ce3= prepared by using (Y1-xCex)2O3 as precursor

    NASA Astrophysics Data System (ADS)

    Liu, Si-Jia; Peng, Tong-Jiang; Song, Zhen; Bian, Liu; Song, Gong-Bao; Liu, Quan-Lin

    2014-04-01

    Trivalent cerium-doped yttrium aluminum garnet (YAG:Ce3=) phosphors are synthesized by solid-state reaction method through using (Y1-xCex)2O3 solid solutions as precursors. Solid solubility limits of Ce3= replacing Y3= in Y2O3 and YAG are determined to be 40% and 7.5%, respectively, based on the relationship between the lattice parameter and chemical composition. Using (Y1-xCex)2O3 as precursors we synthesize YAG:Ce3= single phase at 1450 °C and N2 atmosphere. However, under the same conditions using CeO2 there exists a second phase YAlO3 as impurity. The photoluminescence intensity of YAG:Ce3= increases monotonically with the increase of Ce concentration until it reaches a maximum at solid solubility limits of Ce3= in YAG.

  5. The participation of soluble factors in the omega-oxidation of fatty acids in the liver of the sheep

    SciTech Connect

    Hare, W.R.; Wahle, K.W. )

    1991-02-01

    The removal of soluble components from an ovine hepatic microsomal preparation decreased the omega-hydroxylation of dodecanoic and hexadecanoic acids. The results suggest that one or more soluble components play a role in the microsomal omega-hydroxylation of fatty acids. The possible roles in the reaction of catalase (known to stimulate the microsomal desaturations of fatty acids and alkylglycerols) and superoxide dismutase were investigated. The addition of these enzymes to the complete (but not the washed) microsomal preparation stimulated both the initial omega-hydroxylation reaction and the subsequent dehydrogenation reactions of the omega-oxidation pathway. The similarity of the effects of catalase and superoxide dismutase and stimulation of two different steps of the omega-oxidation pathway suggest that these agents are acting indirectly by removing active oxygen species rather than directly on the enzymes of microsomal fatty acid omega-hydroxylation.

  6. Enhancement of Solubility of Lamotrigine by Solid Dispersion and Development of Orally Disintegrating Tablets Using 32 Full Factorial Design

    PubMed Central

    Singh, Jatinderpal; Garg, Rajeev; Gupta, Ghanshyam Das

    2015-01-01

    Present investigation deals with the preparation and evaluation of orally disintegrating tablets (ODTs) of lamotrigine using β-cyclodextrin and PVP-K30 as polymers for the preparation of solid dispersion which help in enhancement of aqueous solubility of this BCS CLASS-II drug and sodium starch glycolate (SSG) and crospovidone as a superdisintegrating agent, to reduce disintegration time. The ODTs were prepared by direct compression method. Nine formulations were developed with different ratios of superdisintegrating agents. All the formulations were evaluated for disintegration time, weight variation, hardness, friability, drug content uniformity, wetting time, and in vitro drug release study. In vitro drug release study was performed using United States Pharmacopoeia (USP) type 2 dissolution test apparatus employing paddle stirrer at 50 rpm using 900 mL of 0.1 N HCl maintained at 37°C ± 0.5°C as the dissolution medium. On the basis of evaluation parameters formulations were prepared using β-CD 1 : 1 solid dispersion. Then 32 full factorial design was applied using SSG and crospovidone in different ratios suggested by using design expert 8.0.7.1 and optimized formulation was prepared using amount of SSG and crospovidone as suggested by the software. The optimized formulation prepared had disintegrating time of 15 s, wetting time of 24 s, and % friability of 0.55. PMID:26634173

  7. Solid dispersion of quercetin in cellulose derivative matrices influences both solubility and stability.

    PubMed

    Li, Bin; Konecke, Stephanie; Harich, Kim; Wegiel, Lindsay; Taylor, Lynne S; Edgar, Kevin J

    2013-02-15

    Amorphous solid dispersions (ASD) of quercetin (Que) in cellulose derivative matrices, carboxymethylcellulose acetate butyrate (CMCAB), hydroxypropylmethylcellulose acetate succinate (HPMCAS), and cellulose acetate adipate propionate (CAAdP) were prepared with the goal of identifying an ASD that effectively increased Que aqueous solution concentration. Crystalline quercetin and Que/poly(vinylpyrrolidinone) (PVP) ASD were evaluated for comparison. Powder X-ray diffraction (XRPD) and differential scanning calorimetry (DSC) were used to examine the crystallinity of ASDs, physical mixtures (PM) and quercetin. ASDs were amorphous up to 50 wt% Que. Que stability against crystallization and solution concentrations from these ASDs were significantly higher than those observed for physical mixtures and crystalline Que. PVP stabilizes against both Que degradation and recrystallization; in contrast, these carboxylated cellulose derivatives inhibit recrystallization but release Que slowly. PVP ASDs afforded fast and complete drug release, while ASDs using these three cellulose derivatives provide slow, incomplete, pH-triggered drug release. PMID:23399255

  8. Improving solubility, stability, and cellular uptake of resveratrol by nanoencapsulation with chitosan and γ-poly (glutamic acid).

    PubMed

    Jeon, Young Ok; Lee, Ji-Soo; Lee, Hyeon Gyu

    2016-11-01

    Resveratrol (RES), a polyphenolic compound found in grape skins, is a potent antioxidant with broad health benefits. However, its utilization in food has been limited by its poor water solubility, instability, and low bioavailability. The purpose of this study is to improve the solubility, stability, and cellular uptake of RES by nanoencapsulation using chitosan (CS) and γ-poly (glutamic acid) (γ-PGA). The size of nanoparticles significantly decreases with a decrease in the CS/γ-PGA ratio (p<0.05). The nanoparticle size with CS/γ-PGA ratio of 5 was 100-150nm. The entrapment efficiency and UV-light protection effect significantly increases (p<0.05), with an increase in the CS and γ-PGA concentration. The solubility of RES increases 3.2 and 4.2 times before and after lyophilization by nanoencapsulation, respectively. Compared with non-nanoencapsulated RES, the nanoencapsulated RES tends to maintain its solubility and antioxidant activity during storage. CS/γ-PGA nanoencapsulation was able to significantly enhance the transport of RES across a Caco-2 cell monolayer (p<0.05). The highest cellular uptake was found for nanoparticles prepared with 0.5mg/mL CS and 0.1mg/mL γ-PGA, which showed the highest solubility and antioxidant activity during storage. Therefore, CS/γ-PGA nanoencapsulation is found to be a potentially valuable technique for improving the solubility, stability, and cellular uptake of RES. PMID:27518454

  9. Quantifying solubility enhancement due to particle size reduction and crystal habit modification: case study of acetyl salicylic acid.

    PubMed

    Hammond, Robert B; Pencheva, Klimentina; Roberts, Kevin J; Auffret, Tony

    2007-08-01

    The poor solubility of potential drug molecules is a significant problem in the design of pharmaceutical formulations. It is well known, however, that the solubility of crystalline materials is enhanced when the particle size is reduced to submicron levels and this factor can be expected to enhance drug product bioavailability. Direct estimation of solubility enhancement, as calculated via the Gibbs-Thompson relationship, demands reasonably accurate values for the particle/solution interfacial tension and, in particular, its anisotropy with respect to the crystal product's habit and morphology. In this article, an improved, more molecule-centered, approach is presented towards the calculation of solubility enhancement factors in which molecular modeling techniques are applied, and the effects associated with both crystal habit modification and solvent choice are examined. A case study for facetted, acetyl salicylic acid (aspirin) crystals in equilibrium with saturated aqueous ethanol solution reveals that their solubility will be enhanced in the range (7-58%) for a crystal size of 0.02 microm, with significantly higher enhancement for crystal morphologies in which the hydrophobic crystal faces are more predominant than the hydrophilic faces and for solvents in which the solubility is smaller.

  10. Solid state radiolysis of amino acids in an astrochemical perspective

    NASA Astrophysics Data System (ADS)

    Cataldo, Franco; Angelini, Giancarlo; Iglesias-Groth, Susana; Manchado, Arturo

    2011-01-01

    The aliphatic amino acids L-alanine and L-leucine and the aromatic amino acids L-phenylalanine, L-tyrosine and L-tryptophan were irradiated in the solid state to a dose of 3.2 MGy. The degree of decomposition was measured by differential scanning calorimetry (DSC). Furthermore the degree of radioracemization was measured by optical rotatory dispersion (ORD) spectroscopy. From the DSC measurement a radiolysis rate constant k and the half life T1/2 for each amino acid have been determined and extrapolated to a dose of 14 MGy, which corresponds to the expected total dose delivered by the decay of radionuclides to the organic molecules present in comets and asteroids in 4.6×109 years, the age of the Solar System. It is shown that all the amino acids studied can survive a radiation dose of 14 MGy although they are reduced to 1/4-1/5 of their original value they had at the beginning of the history of the Solar System. Consequently, the amount of alanine or leucine found today in the meteorites known as carbonaceous chondrites is just 1/4-1/5 of the amount originally present at the epoch of the formation of the Solar System 4.6×109 years ago. Among the amino acids studied, tyrosine shows the highest radiation resistance while tryptophan does not combine its relatively high radiation resistance with an elevated level of radioracemization resistance. Apart from the exception of tryptophan, it is shown that the radiolysis rate constants k of all the amino acids studied are in reasonable agreement with the radioracemization rate constant krac.

  11. Measurement of moisture, soluble solids, and sucrose content and mechanical properties in sugar beet using portable visible and near-infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Visible and near-infrared spectroscopy, coupled with partial least squares regression, was used to predict the moisture, soluble solids and sucrose content and mechanical properties of sugar beet. Interactance spectra were acquired from both intact and sliced beets, using two portable spectrometers ...

  12. Design, synthesis, structure, and dehydrogenation reactivity of a water-soluble o-iodoxybenzoic acid derivative bearing a trimethylammonium group.

    PubMed

    Cui, Li-Qian; Dong, Zhi-Lei; Liu, Kai; Zhang, Chi

    2011-12-16

    5-Trimethylammonio-1,3-dioxo-1,3-dihydro-1λ(5)-benzo[d][1,2]iodoxol-1-ol anion (AIBX 1a), an o-iodoxybenzoic acid (IBX) derivative having the trimethylammonium moiety on its phenyl ring, possesses very good solubility in water and distinct oxidative properties from IBX, which is demonstrated in the oxidation of various β-keto esters to the corresponding dehydrogenated products using water as cosolvent. The regeneration of AIBX 1a can be easily realized from the reaction mixture due to its good water solubility. PMID:22082110

  13. Design, synthesis, structure, and dehydrogenation reactivity of a water-soluble o-iodoxybenzoic acid derivative bearing a trimethylammonium group.

    PubMed

    Cui, Li-Qian; Dong, Zhi-Lei; Liu, Kai; Zhang, Chi

    2011-12-16

    5-Trimethylammonio-1,3-dioxo-1,3-dihydro-1λ(5)-benzo[d][1,2]iodoxol-1-ol anion (AIBX 1a), an o-iodoxybenzoic acid (IBX) derivative having the trimethylammonium moiety on its phenyl ring, possesses very good solubility in water and distinct oxidative properties from IBX, which is demonstrated in the oxidation of various β-keto esters to the corresponding dehydrogenated products using water as cosolvent. The regeneration of AIBX 1a can be easily realized from the reaction mixture due to its good water solubility.

  14. Relative effectiveness of various anions on the solubility of acidic Hypoderma lineatum collagenase at pH 7.2.

    PubMed Central

    Carbonnaux, C.; Ries-Kautt, M.; Ducruix, A.

    1995-01-01

    The effects of various anions on decreasing the solubility of acidic Hypoderma lineatum collagenase at pH 7.2 and 18 degrees C were qualitatively defined by replacing the crystallizing agent of known crystallization conditions by various ammonium salts. The solubility curves measured in the presence of the sulfate, phosphate, citrate, and chloride ammonium salts gave the following ranking of anions: HPO4(2-)/H2PO4- > SO4(2-) > citrate 3-/citrate2- >> Cl-. This order is in agreement with the Hofmeister series. In a previous study on the solubility at pH 4.5 of lysozyme, a basic protein, the effectiveness of anions in decreasing the solubility was found to be in the reverse order. This suggests that the effectiveness of anions in the crystallization of proteins is dependent on the net charge of the protein, i.e., depending on whether a basic protein is crystallized at acidic pH or an acidic protein at basic pH. PMID:8535249

  15. Influence of acid-soluble proteins from bivalve Siliqua radiata ligaments on calcium carbonate crystal growth

    NASA Astrophysics Data System (ADS)

    Huang, Zeng-Qiong; Zhang, Gang-Sheng

    2016-08-01

    In vitro biomimetic synthesis of calcium carbonate (CaCO3) in the presence of shell proteins is a heavily researched topic in biomineralization. However, little is known regarding the function of bivalve ligament proteins in the growth of CaCO3 crystals. In this study, using fibrous protein K58 from Siliqua radiata ligaments or coverslips as substrates, we report the results of our study of CaCO3 precipitation in the presence or absence of acid-soluble proteins (ASP) from inner ligament layers. ASP can disturb the controlling function of K58 or a coverslip on the crystalline phase, resulting in the formation of aragonite, calcite, and vaterite. In addition, we identified the following four primary components from ASP by mass spectroscopy: alkaline phosphatase (ALP), ABC transporter, keratin type II cytoskeletal 1 (KRT 1), and phosphate ABC transporter, phosphate-binding protein (PstS). Further analysis revealed that the first three proteins and especially ALP, which is important in bone mineralisation, could affect the polymorphism and morphology of CaCO3 crystals by trapping calcium ions in their domains. Our results indicate that ALP may play an important role in the formation of aragonite in S. radiata ligaments. This paper may facilitate our understanding of the biomineralization process.

  16. Adsorption and condensation of amino acids and nucleotides with soluble mineral salts

    NASA Technical Reports Server (NTRS)

    Orenberg, J.; Lahav, N.

    1986-01-01

    The directed synthesis of biopolymers in an abiotic environment is presumably a cyclic sequence of steps which may be realized in a fluctuating environment such as a prebiotic pond undergoing wetting-drying cycles. Soluble mineral salts have been proposed as an essential component of this fluctuating environment. The following sequence may be considered as a most primitive mechanism of information transfer in a fluctuating environment: (1) adsorption of a biomolecule onto a soluable mineral salt surface to act as an adsorbed template; (2) specific adsorption of biomonomers onto the adsorbed template; (3) condensation of the adsorbed biomonomers; and (4) desorption of the elongated oligomer. In this investigation, the salts selected for study were CaSO4.2H2O(gypsum), SrSO4, and several other metal sulfates and chlorides. Adsorption of the monomeric species, gly, 5'AMP 5'GMP, and 5'CMP was investigated. The adsorbed template biopolymers used were Poly-A, Poly-G, Poly-C, and Poly-U. The results of studies involving these experimental participants, the first two steps of the proposed primitive information transfer mechanism, and condensation of amino acids to form oligomers in a fluctuating environment are to be reported.

  17. Acid-Soluble Nucleotides of Pinto Bean Leaves at Different Stages of Development 1

    PubMed Central

    Weinstein, L. H.; McCune, D. C.; Mancini, Jill F.; van Leuken, P.

    1969-01-01

    Acid-soluble nucleotides of unifoliate leaves of Pinto bean plants (Phaseolus vulgaris L.) were determined at young, mature, and senescent stages of development. At least 25 components could be distinguished on the basis of inorganic phosphorus determinations and 37 or more fractions on the basis of 32P labeling, with adenosine di- and triphosphates accounting for 60% of the total moles of nucleotide. The total nucleotide P and inorganic P, on a fresh weight basis, decreased about 44% between each stage of leaf development, but decrements in the levels of individual nucleotides varied from this over-all pattern. Minor changes in the relative abundance of the individual nucleotides accompanied aging although the percentage of purine-containing nucleotides decreased with age. Total 32P activity per leaf in the nucleotide pool increased about 3-fold between the young and mature leaves and decreased slightly as leaves became senescent. In general, the specific activities of the nucleotides increased with increased age and adenosine-, guanosine-, uridine-, and cytidine triphosphates and adenosine diphosphate accounted for approximately 90% of the total activity. The changes in the relative sizes and energy status of the nucleotide pools were not so obvious as the changes in other metabolites that have been reported to accompany aging in leaf tissue. PMID:16657232

  18. Replica exchange molecular dynamics simulations of an α/β-type small acid soluble protein (SASP).

    PubMed

    Ojeda-May, P; Pu, Jingzhi

    2013-12-31

    Small acid soluble proteins (SASPs) of α/β-type play a major role in the resistance of spore DNAs to external assaults. It has been found that α/β-type SASP exhibits intrinsic disorder on isolation, but it acquires a defined native state upon binding to DNA. This disorder to order transition is not yet understood. Other questions related to the role of the thermodynamics and structure of the individual protein in the complex formation remain elusive. Characterization of the unbound state of α/β-type SASP in experiments could be a challenging problem because of the heterogeneous nature of the ensemble. Here, computer simulations can help gain more insights into the unbound state of α/β-type SASP. In the present work, by using replica exchange molecular dynamics (REMD), we simulated an α/β-type SASP on isolation with an implicit solvent. We found that α/β-type SASP undergoes a continuous phase transition with a small free energy barrier, a common feature of intrinsically disordered proteins (IDPs). Additionally, we detected the presence of residual α-helical structures at local level and a high degree of plasticity in the chain which can contribute to the fast disorder to order transition by reducing the fly-casting mechanism.

  19. [Effects of simulated acid rain and its acidified soil on soluble sugar and nitrogen contents of wheat seedlings].

    PubMed

    Tong, Guanhe; Liang, Huiling

    2005-08-01

    The study showed that the cation release of simulated rain caused soil acidification and base ions release. With the decrease of simulated acid rain pH from 5.6 to 2.5, the acid rain-leached soil pH decreased from 6.06 to 3.41, and its total amount of exchange base ions decreased from 56.5 to 41.1 mmol x kg(-1). Spraying simulated acid rain on the shoots of wheat seedlings planted on such acidified soils caused a rapid decrease in the soluble sugar and nitrogen contents of wheat seedlings, and reduced some of their physiological activities. The effect of spraying simulated acid rain on the soluble sugar, nitrogen, and chlorophyll contents and photosynthetic rate of wheat stems and leaves was larger than that of acidified soil, while the effect of the latter on the soluble sugar and nitrogen contents and the physiological activity of NR and GOGAT in root system of wheat seedlings was larger than that of the former. The intensive acid rain of pH < or = 3.0 and the corresponding acidified soil had an obvious harm to the growth and physiological activity of wheat seedlings.

  20. [Effects of simulated acid rain and its acidified soil on soluble sugar and nitrogen contents of wheat seedlings].

    PubMed

    Tong, Guanhe; Liang, Huiling

    2005-08-01

    The study showed that the cation release of simulated rain caused soil acidification and base ions release. With the decrease of simulated acid rain pH from 5.6 to 2.5, the acid rain-leached soil pH decreased from 6.06 to 3.41, and its total amount of exchange base ions decreased from 56.5 to 41.1 mmol x kg(-1). Spraying simulated acid rain on the shoots of wheat seedlings planted on such acidified soils caused a rapid decrease in the soluble sugar and nitrogen contents of wheat seedlings, and reduced some of their physiological activities. The effect of spraying simulated acid rain on the soluble sugar, nitrogen, and chlorophyll contents and photosynthetic rate of wheat stems and leaves was larger than that of acidified soil, while the effect of the latter on the soluble sugar and nitrogen contents and the physiological activity of NR and GOGAT in root system of wheat seedlings was larger than that of the former. The intensive acid rain of pH < or = 3.0 and the corresponding acidified soil had an obvious harm to the growth and physiological activity of wheat seedlings. PMID:16262064

  1. Preparation and In Vitro/In Vivo Characterization of Porous Sublingual Tablets Containing Ternary Kneaded Solid System of Vinpocetine with β-Cyclodextrin and Hydroxy Acid

    PubMed Central

    Aburahma, Mona H.; El-Laithy, Hanan M.; Hamza, Yassin El-Said

    2010-01-01

    The demand for sublingual tablets has been growing during the previous decades especially for drugs with extensive hepatic first-pass metabolism. Vinpocetine, a widely used neurotropic agent, has low oral bioavailability due to its poor aqueous solubility and marked first-pass metabolism. Accordingly, the aim of this work was to develop tablets for the sublingual delivery of vinpocetine. Initially, the feasibility of improving vinpocetine’s poor aqueous solubility by preparing kneaded solid systems of the drug with β-Cyclodextrin and hydroxy acids (citric acid and tartaric acid) was assessed. The solid system with improved solubility and dissolution properties was incorporated into porous tablets that rapidly disintegrate permitting fast release of vinpocetine into the sublingual cavity. The pores were induced into these tablets by directly compressing the tablets’ excipients with a sublimable material, either camphor or menthol, which was eventually sublimated leaving pores. The obtained results demonstrated that the tablets prepared using camphor attained sufficient mechanical strength for practical use together with rapid disintegration and dissolution. In vivo absorption study performed in rabbits indicated that the sublingual administration of the proposed porous tablets containing vinpocetine solid system with β-Cyclodextrin and tartaric acid could be useful for therapeutic application. PMID:21179352

  2. Enhancement of the water solubility of organic pollutants such as pyrene and atrazine by dissolved humic and fulvic acids

    SciTech Connect

    Patterson, H.H.; MacDonald, B.; Fang, F.

    1995-12-31

    Many factors determine the fate and transport of an organic pollutant in the environment but water solubility is certainly one of the most important. Among the environmental factors that alter the solubility of a molecule are naturally occurring humic and fulvic acids. We have hypothesized that the humic/fulvic acids from different sources within a watershed have different binding affinities for pollutants such as pyrene and atrazine. This could lead to different rates of transport or bioavailability within the watershed. Humic/fulvic acids were isolated from a stream, adjacent wetland and nearby wooded upland sites. A fluorescence quenching method was developed to quantify the binding coefficient of the pollutants with the dissolved organic carbon. From these results a model was constructed to determine the sites with the greatest potential to modify pollutant contamination in the environment.

  3. A review on synthesis and characterization of solid acid materials for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Mohammad, Norsyahida; Mohamad, Abu Bakar; Kadhum, Abdul Amir H.; Loh, Kee Shyuan

    2016-08-01

    Solid acids emerged as an electrolyte material for application in fuel cells due to their high protonic conductivity and stability at high temperatures between 100 °C and 250 °C. This paper gives an overview of the different solid acid materials and their properties, such as high protonic conductivity and thermal stability, in relation to phase transitions and mechanisms of proton transport. Various solid acid synthesis methods including aqueous and dry mixing, electrospinning, sol-gel, impregnation and thin-film casting will be discussed, and the impact of synthesis methods on the properties of solid acids will be highlighted. The properties of solid acids synthesized as either single crystals and or polycrystalline powders were identified via X-ray diffraction, nuclear magnetic resonance, thermal analyses, optical microscopy and infrared spectroscopy. A selection of electrolyte-electrode assembly methods and the performance of solid acid fuel cell prototypes are also reviewed.

  4. J-aggregation of a water-soluble tetracationic porphyrin in mixed LB films with a calix[8]arene carboxylic acid derivative.

    PubMed

    Miguel, Gustavo de; Pérez-Morales, Marta; Martín-Romero, María T; Muñoz, Eulogia; Richardson, Tim H; Camacho, Luis

    2007-03-27

    The molecular organization of a mixed film, containing a water-soluble tetracationic porphyrin (TMPyP) and a p-tert-butyl calix[8]arene octacarboxylic acid derivative (C8A), at the air-water interface and on a solid support (LB film), has been investigated. Although the TMPyP aggregation was not detected at the air-water interface, TMPyP J-aggregates have been found in the LB films (Y-type). Unlike tetraanionic porphyrins, for example TSPP, the TMPyP J-aggregates are not induced by a zwitterion formation. The TMPyP J-aggregation is a result of a "double comb" configuration, where porphyrins from opposite layers are interwoven in a linear infinite J-aggregate. Our results confirm that TMPyP molecules tend to self-aggregate strongly, provided the electrostatic repulsions of their peripheral groups are cancelled by the anionic groups of the C8A matrix.

  5. Soluble epoxide hydrolase contamination of specific catalase preparations inhibits epoxyeicosatrienoic acid vasodilation of rat renal arterioles.

    PubMed

    Gauthier, Kathryn M; Olson, Lauren; Harder, Adam; Isbell, Marilyn; Imig, John D; Gutterman, David D; Falck, J R; Campbell, William B

    2011-10-01

    Cytochrome P-450 metabolites of arachidonic acid, the epoxyeicosatrienoic acids (EETs) and hydrogen peroxide (H(2)O(2)), are important signaling molecules in the kidney. In renal arteries, EETs cause vasodilation whereas H(2)O(2) causes vasoconstriction. To determine the physiological contribution of H(2)O(2), catalase is used to inactivate H(2)O(2). However, the consequence of catalase action on EET vascular activity has not been determined. In rat renal afferent arterioles, 14,15-EET caused concentration-related dilations that were inhibited by Sigma bovine liver (SBL) catalase (1,000 U/ml) but not Calbiochem bovine liver (CBL) catalase (1,000 U/ml). SBL catalase inhibition was reversed by the soluble epoxide hydrolase (sEH) inhibitor tAUCB (1 μM). In 14,15-EET incubations, SBL catalase caused a concentration-related increase in a polar metabolite. Using mass spectrometry, the metabolite was identified as 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), the inactive sEH metabolite. 14,15-EET hydrolysis was not altered by the catalase inhibitor 3-amino-1,2,4-triazole (3-ATZ; 10-50 mM), but was abolished by the sEH inhibitor BIRD-0826 (1-10 μM). SBL catalase EET hydrolysis showed a regioisomer preference with greatest hydrolysis of 14,15-EET followed by 11,12-, 8,9- and 5,6-EET (V(max) = 0.54 ± 0.07, 0.23 ± 0.06, 0.18 ± 0.01 and 0.08 ± 0.02 ng DHET·U catalase(-1)·min(-1), respectively). Of five different catalase preparations assayed, EET hydrolysis was observed with two Sigma liver catalases. These preparations had low specific catalase activity and positive sEH expression. Mass spectrometric analysis of the SBL catalase identified peptide fragments matching bovine sEH. Collectively, these data indicate that catalase does not affect EET-mediated dilation of renal arterioles. However, some commercial catalase preparations are contaminated with sEH, and these contaminated preparations diminish the biological activity of H(2)O(2) and EETs.

  6. Soluble epoxide hydrolase contamination of specific catalase preparations inhibits epoxyeicosatrienoic acid vasodilation of rat renal arterioles.

    PubMed

    Gauthier, Kathryn M; Olson, Lauren; Harder, Adam; Isbell, Marilyn; Imig, John D; Gutterman, David D; Falck, J R; Campbell, William B

    2011-10-01

    Cytochrome P-450 metabolites of arachidonic acid, the epoxyeicosatrienoic acids (EETs) and hydrogen peroxide (H(2)O(2)), are important signaling molecules in the kidney. In renal arteries, EETs cause vasodilation whereas H(2)O(2) causes vasoconstriction. To determine the physiological contribution of H(2)O(2), catalase is used to inactivate H(2)O(2). However, the consequence of catalase action on EET vascular activity has not been determined. In rat renal afferent arterioles, 14,15-EET caused concentration-related dilations that were inhibited by Sigma bovine liver (SBL) catalase (1,000 U/ml) but not Calbiochem bovine liver (CBL) catalase (1,000 U/ml). SBL catalase inhibition was reversed by the soluble epoxide hydrolase (sEH) inhibitor tAUCB (1 μM). In 14,15-EET incubations, SBL catalase caused a concentration-related increase in a polar metabolite. Using mass spectrometry, the metabolite was identified as 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), the inactive sEH metabolite. 14,15-EET hydrolysis was not altered by the catalase inhibitor 3-amino-1,2,4-triazole (3-ATZ; 10-50 mM), but was abolished by the sEH inhibitor BIRD-0826 (1-10 μM). SBL catalase EET hydrolysis showed a regioisomer preference with greatest hydrolysis of 14,15-EET followed by 11,12-, 8,9- and 5,6-EET (V(max) = 0.54 ± 0.07, 0.23 ± 0.06, 0.18 ± 0.01 and 0.08 ± 0.02 ng DHET·U catalase(-1)·min(-1), respectively). Of five different catalase preparations assayed, EET hydrolysis was observed with two Sigma liver catalases. These preparations had low specific catalase activity and positive sEH expression. Mass spectrometric analysis of the SBL catalase identified peptide fragments matching bovine sEH. Collectively, these data indicate that catalase does not affect EET-mediated dilation of renal arterioles. However, some commercial catalase preparations are contaminated with sEH, and these contaminated preparations diminish the biological activity of H(2)O(2) and EETs. PMID:21753077

  7. Malate plays a crucial role in starch metabolism, ripening, and soluble solid content of tomato fruit and affects postharvest softening.

    PubMed

    Centeno, Danilo C; Osorio, Sonia; Nunes-Nesi, Adriano; Bertolo, Ana L F; Carneiro, Raphael T; Araújo, Wagner L; Steinhauser, Marie-Caroline; Michalska, Justyna; Rohrmann, Johannes; Geigenberger, Peter; Oliver, Sandra N; Stitt, Mark; Carrari, Fernando; Rose, Jocelyn K C; Fernie, Alisdair R

    2011-01-01

    Despite the fact that the organic acid content of a fruit is regarded as one of its most commercially important quality traits when assessed by the consumer, relatively little is known concerning the physiological importance of organic acid metabolism for the fruit itself. Here, we evaluate the effect of modifying malate metabolism in a fruit-specific manner, by reduction of the activities of either mitochondrial malate dehydrogenase or fumarase, via targeted antisense approaches in tomato (Solanum lycopersicum). While these genetic perturbations had relatively little effect on the total fruit yield, they had dramatic consequences for fruit metabolism, as well as unanticipated changes in postharvest shelf life and susceptibility to bacterial infection. Detailed characterization suggested that the rate of ripening was essentially unaltered but that lines containing higher malate were characterized by lower levels of transitory starch and a lower soluble sugars content at harvest, whereas those with lower malate contained higher levels of these carbohydrates. Analysis of the activation state of ADP-glucose pyrophosphorylase revealed that it correlated with the accumulation of transitory starch. Taken together with the altered activation state of the plastidial malate dehydrogenase and the modified pigment biosynthesis of the transgenic lines, these results suggest that the phenotypes are due to an altered cellular redox status. The combined data reveal the importance of malate metabolism in tomato fruit metabolism and development and confirm the importance of transitory starch in the determination of agronomic yield in this species.

  8. Purified membrane and soluble folate binding proteins from cultured KB cells have similar amino acid compositions and molecular weights but differ in fatty acid acylation.

    PubMed Central

    Luhrs, C A; Pitiranggon, P; da Costa, M; Rothenberg, S P; Slomiany, B L; Brink, L; Tous, G I; Stein, S

    1987-01-01

    A membrane-associated folate binding protein (FBP) and a soluble FBP, which is released into the culture medium, have been purified from human KB cells using affinity chromatography. By NaDodSO4/PAGE, both proteins have an apparent Mr of approximately 42,000. However, in the presence of Triton X-100, the soluble FBP eluted from a Sephadex G-150 column with an apparent Mr of approximately 40,000 (similar to NaDodSO4/PAGE) but the membrane-associated FBP eluted with an apparent Mr of approximately 160,000, indicating that this species contains a hydrophobic domain that interacts with the detergent micelles. The amino acid compositions of both forms of FBP were similar, especially with respect to the apolar amino acids. In addition, the 18 amino acids at the amino termini of both proteins were identical. The membrane FBP, following delipidation with chloroform/methanol, contained 7.1 mol of fatty acid per mol of protein, of which 4.7 mol was amide-linked and 2.4 mol was ester-linked. The soluble FBP contained only 0.05 mol of fatty acid per mol of protein. These studies indicate that the membrane FBP of KB cells contains covalently bound fatty acids that may serve to anchor the protein in the cell membrane. Images PMID:3476960

  9. Purified membrane and soluble folate binding proteins from cultured KB cells have similar amino acid compositions and molecular weights but differ in fatty acid acylation

    SciTech Connect

    Luhrs, C.A.; Pitiranggon, P.; Costa, M.D.; Rothenberg, S.P.; Slomiany, B.L.; Brink, L.; Tous, G.I.; Stein, S.

    1987-09-01

    A membrane-associated folate binding protein (FBP) and a soluble FBP, which is released into the culture medium, have been purified from human KB cells using affinity chromatography. By NaDodSO/sub 4/PAGE, both proteins have an apparent M/sub r/ of approx. 42,000. However, in the presence of Triton X-100, the soluble FBP eluted from a Sephadex G-150 column with an apparent M/sub r/ of approx. 40,000 (similar to NaDodSO/sub 4/PAGE) but the membrane-associated FBP eluted with an apparent M/sub r/ of approx. = 160,000, indicating that this species contains a hydrophobic domain that interacts with the detergent micelles. The amino acid compositions of both forms of FBP were similar, especially with respect to the apolar amino acids. In addition, the 18 amino acids at the amino termini of both proteins were identical. The membrane FBP, following delipidation with chloroformmethanol, contained 7.1 mol of fatty acid per mol of protein, of which 4.7 mol was amide-linked and 2.4 mol was ester-linked. The soluble FBP contained only 0.05 mol of fatty acid per mol of protein. These studies indicate that the membrane FBP of KB cells contains covalently bound fatty acids that may serve to anchor the protein in the cell membrane.

  10. Removal and recovery of furfural, 5-hydroxymethylfurfural, and acetic acid from aqueous solutions using a soluble polyelectrolyte.

    PubMed

    Carter, Brian; Gilcrease, Patrick C; Menkhaus, Todd J

    2011-09-01

    In the cellulosic ethanol process, furfural, 5-hydroxymethylfurfural (HMF), and acetic acid are formed during the high temperature acidic pretreatment step needed to convert biomass into fermentable sugars. These compounds can inhibit cellulase enzymes and fermentation organisms at relatively low concentrations (≥ 1 g/L). Effective removal of these inhibitory compounds would allow the use of more severe pretreatment conditions to improve sugar yields and lead to more efficient fermentations; if recovered and purified, they could also be sold as valuable by-products. This study investigated the separation of aldhehydes (furfural and HMF) and organic acid (acetic acid) inhibitory compounds from simple aqueous solutions by using polyethyleneimene (PEI), a soluble cationic polyelectrolyte. PEI added to simple solutions of each inhibitor at a ratio of 1 mol of functional group to 1 mol inhibitor removed up to 89.1, 58.6, and 81.5 wt% of acetic acid, HMF, and furfural, respectively. Furfural and HMF were recovered after removal by washing the polyelectrolyte/inhibitor complex with dilute sulfuric acid solution. Recoveries up to 81.0 and 97.0 wt% were achieved for furfural and HMF, respectively. The interaction between PEI and acetic acid was easily disrupted by the addition of chloride ions, sulfate ions, or hydroxide ions. The use of soluble polymers for the removal and recovery of inhibitory compounds from biomass slurries is a promising approach to enhance the efficiency and economics of an envisioned biorefinery.

  11. Prevention of Acid Mine Drainage Through Complexation of Ferric Iron by Soluble Microbial Growth Products

    NASA Astrophysics Data System (ADS)

    Pandey, S.; Yacob, T. W.; Silverstein, J.; Rajaram, H.; Minchow, K.; Basta, J.

    2011-12-01

    Acid mine drainage (AMD) is a widespread environmental problem with deleterious impacts on water quality in streams and watersheds. AMD is generated largely by the oxidation of metal sulfides (i.e. pyrite) by ferric iron. This abiotic reaction is catalyzed by conversion of ferrous to ferric iron by iron and sulfur oxidizing microorganisms. Biostimulation is currently being investigated as an attempt to inhibit the oxidation of pyrite and growth of iron oxidizing bacteria through addition of organic carbon. This may stimulate growth of indigenous communities of acidophilic heterotrophic bacteria to compete for oxygen. The goal of this research is to investigate a secondary mechanism associated with carbon addition: complexation of free Fe(III) by soluble microbial growth products (SMPs) produced by microorganisms growing in waste rock. Exploratory research at the laboratory scale examined the effect of soluble microbial products (SMPs) on the kinetics of oxidation of pure pyrite during shaker flask experiments. The results confirmed a decrease in the rate of pyrite oxidation that was dependent upon the concentration of SMPs in solution. We are using these data to verify results from a pyrite oxidation model that accounts for SMPs. This reactor model involves differential-algebraic equations incorporating total component mass balances and mass action laws for equilibrium reactions. Species concentrations determined in each time step are applied to abiotic pyrite oxidation rate expressions from the literature to determine the evolution of total component concentrations. The model was embedded in a parameter estimation algorithm to determine the reactive surface area of pyrite in an abiotic control experiment, yielding an optimized value of 0.0037 m2. The optimized model exhibited similar behavior to the experiment for this case; the root mean squared of residuals for Fe(III) was calculated to be 7.58 x 10-4 M, which is several orders of magnitude less than the actual

  12. Spectroscopic Studies of Polymer Structure in the Solid State and Water Soluble Complexes

    NASA Astrophysics Data System (ADS)

    Cha, Hyukjin

    The chemical changes before and after sulfonation of poly(ether ether ketone) (PEEK) were studied by using x-ray photoelectron spectroscopy (XPS). The inelastic mean free path (IMFP) of the photoelectrons was also measured by controlling the overlayer film thickness. The measured IMFP values for the C 1s, O 1s, S 2p and Si 2p photoelectrons were 30 +/- 3 A, 28 +/- 2 A, 34 +/- 2 Aand 35 +/- 3 A, respectively. Based on angle-resolved x-ray photoelectron spectroscopy (ARXPS) experiments, the concentration profiles and the diffusion constant D for interdiffusion of SPEEK into PEEK film could be determined. The measured diffusion coefficients varied from 3 times 10^{-15} rm cm ^2/sec (@ 583 K) to 6 times 10^{-18} (@ 443 K) cm ^2/sec. The activation energy derived from the measured diffusion coefficients was 22.8 kcal/mol. In addition, the molecular level conformational changes of poly(ether ether ketone) (PEEK) with temperature were studied by using fluorescence spectroscopy. In order to identify the origins of PEEK fluorescence, a model compound for PEEK was synthesized and characterized by UV-visible spectroscopy and fluorescence spectroscopy. The characteristic emission bands at 434 nm and 490 nm were monitored in order to understand local conformational changes of the polymer chain during the thermal treatment process. The changes in relative intensity ratio rm(I_{490}/I _{434}) were compared with differential scanning calorimeter and X-ray scattering data, and were explained in view of molecular morphology. In order to understand polymer complexation in solution, three different systems were studied. First, molecular binding between poly(acrylic acid) (PAA) and europium chloride hexahydrate rm(EuCl_3 6H_2O) and their chain conformations during the complexation process in aqueous solution was studied using fluorescence and IR spectroscopy. Second, complexation of poly(vinyl alcohol sulfate) (KPVS) with papain was investigated with fluorescence and UV absorption

  13. Starch saccharification by carbon-based solid acid catalyst

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Daizo; Hara, Michikazu

    2010-06-01

    The hydrolysis of cornstarch using a highly active solid acid catalyst, a carbon material bearing SO 3H, COOH and OH groups, was investigated at 353-393 K through an analysis of variance (ANOVA) and an artificial neural network (ANN). ANOVA revealed that reaction temperature and time are significant parameters for the catalytic hydrolysis of starch. The ANN model indicated that the reaction efficiency reaches a maximum at an optimal condition (water, 0.8-1.0 mL; starch, 0.3-0.4 g; catalyst, 0.3 g; reaction temperature, 373 K; reaction time, 3 h). The relationship between the reaction and these parameters is discussed on the basis of the reaction mechanism.

  14. Water soluble complex of palmitic acid in media for cultivation of leprosy-derived psychrophilic mycobacteria from Mycobacterium leprae infected tissues.

    PubMed

    Kátó, L; Szejtli, J; Szente, L

    1993-01-01

    Palmitic acid and palmitates were transformed into water soluble complexes with crystalline heptakis-2,6-di-0-methyl-beta-cyclodextrin. This formulation was incorporated into liquid and solid chemically well-defined media. The fatty acid served as C and energy source, ammonium thioglycolate as the sole source of N with the SH group as further source of energy. Minute amount of dimethyl-sulfoxide added was used for its known effect on cell membrane permeability. The media were inoculated with host grown Mycobacterium leprae cells isolated from human, armadillo and Nu mice foot pad lepromata. No growth occurred in the liquid medium at 22 or 32 degrees C, but cultures and subcultures of acid fast rods were grown at 10 degrees C. Bacilli in the cultures were solid, strongly acid fast rods, growing in clumps like globi. Growth on the semisolid media was visible as smooth round colonies, of white to ivory in colour, slowly expanding flatly at the periphery of the colony on the agar surface. Colonies developed within 2-3 weeks and reached maximum size at 50-80 days depending on the size of inoculum. Subcultures grow faster and more abundantly with adaptation to the media. No growth was seen without the water soluble complexes of palmitic acid or palmitates in the media. The free fatty acid or its salts had an equal growth supporting effect. Identical psychrophilic cultures were obtained from 7 out of 9 armadillo, 12 out of 12 Nu mice and 1 out of 2 human lepromata. None of the cultures grow on Loewenstein, Dubos or 7H9 media at 10 degrees C, 20 degrees C or 32 degrees C, respectively. The tested 4th to 7th subcultures of the strains were strongly positive for phenolic glycolipid-1. Heat killed suspensions of up to 7th subcultures gave negative late skin reaction in all of 16 LL cases. In 19 I, B and T cases the late skin reactions were all similar to that obtained with authentic human lepromin.

  15. Inter-relationships between solubilities, distribution coefficients and melting points of some substituted benzoic and phenylacetic acids.

    PubMed

    Armstrong, N A; James, K C; Wong, C K

    1979-09-01

    Ten 4-hydroxy and 4-alkoxy benzoic and phenylalkanoic acids have been investigated. Solubilities in aqueous buffer at pH 1.2 were determined, together with distribution coefficients between the buffer and either octanol or isopropyl myristate. When plotted against the total number of carbon atoms in the side chains, log octanol/water distribution coefficients gave two parallel straight lines, one for the substituted benzoic acids, and the other for the substituted phenylalkanoic acids. The slopes approximated to 0.5, the generally accepted value for methylene. Similar plots could be obtained with isopropyl myristate, provided the hydroxy acid results were ignored, and also when log aqueous solubilities were plotted against carbon number, although there was considerable scatter. The differences between the distribution coefficient results were explained in terms of solute-solvent interactions, and the scatter attributed to variations in the heats of fusion of the solutes. Yalkowsky's equation (1977), linking aqueous solubilities and melting points with distribution coefficients, was applied to the results, and found to be of limited predictive value. PMID:41067

  16. [Characteristic wavelengths selection of soluble solids content of pear based on NIR spectral and LS-SVM].

    PubMed

    Fan, Shu-xiang; Huang, Wen-qian; Li, Jiang-bo; Zhao, Chun-jiang; Zhang, Bao-hua

    2014-08-01

    To improve the precision and robustness of the NIR model of the soluble solid content (SSC) on pear. The total number of 160 pears was for the calibration (n=120) and prediction (n=40). Different spectral pretreatment methods, including standard normal variate (SNV) and multiplicative scatter correction (MSC) were used before further analysis. A combination of genetic algorithm (GA) and successive projections algorithm (SPA) was proposed to select most effective wavelengths after uninformative variable elimination (UVE) from original spectra, SNV pretreated spectra and MSC pretreated spectra respectively. The selected variables were used as the inputs of least squares-support vector machine (LS-SVM) model to build models for de- termining the SSC of pear. The results indicated that LS-SVM model built using SNVE-UVE-GA-SPA on 30 characteristic wavelengths selected from full-spectrum which had 3112 wavelengths achieved the optimal performance. The correlation coefficient (Rp) and root mean square error of prediction (RMSEP) for prediction sets were 0.956, 0.271 for SSC. The model is reliable and the predicted result is effective. The method can meet the requirement of quick measuring SSC of pear and might be important for the development of portable instruments and online monitoring.

  17. Acute and Chronic Toxicity of Soluble Fractions of Industrial Solid Wastes on Daphnia magna and Vibrio fischeri

    PubMed Central

    Flohr, Letícia; de Castilhos Júnior, Armando Borges; Matias, William Gerson

    2012-01-01

    Industrial wastes may produce leachates that can contaminate the aquatic ecosystem. Toxicity testing in acute and chronic levels is essential to assess environmental risks from the soluble fractions of these wastes, since only chemical analysis may not be adequate to classify the hazard of an industrial waste. In this study, ten samples of solid wastes from textile, metal-mechanic, and pulp and paper industries were analyzed by acute and chronic toxicity tests with Daphnia magna and Vibrio fischeri. A metal-mechanic waste (sample MM3) induced the highest toxicity level to Daphnia magna(CE50,48 h = 2.21%). A textile waste induced the highest toxicity level to Vibrio fischeri (sample TX2, CE50,30 min = 12.08%). All samples of pulp and paper wastes, and a textile waste (sample TX2) induced chronic effects on reproduction, length, and longevity of Daphnia magna. These results could serve as an alert about the environmental risks of an inadequate waste classification method. PMID:22619632

  18. Effect of guava (Psidium guajava Linn.) leaf soluble solids on glucose metabolism in type 2 diabetic rats.

    PubMed

    Shen, Szu-Chuan; Cheng, Fang-Chi; Wu, Ning-Jung

    2008-11-01

    This study investigated the effect of aqueous and ethanol soluble solid extracts of guava (Psidium guajava Linn.) leaves on hypoglycemia and glucose metabolism in type 2 diabetic rats. Low-dose streptozotocin (STZ) and nicotinamide were injected into Sprague-Dawley (SD) rats to induce type 2 diabetes. Acute and long-term feeding tests were carried out, and an oral glucose tolerance test (OGTT) to follow the changes in plasma glucose and insulin levels was performed to evaluate the antihyperglycemic effect of guava leaf extracts in diabetic rats.The results of acute and long-term feeding tests showed a significant reduction in the blood sugar level in diabetic rats fed with either the aqueous or ethanol extract of guava leaves (p < 0.05). Long-term administration of guava leaf extracts increased the plasma insulin level and glucose utilization in diabetic rats. The results also indicated that the activities of hepatic hexokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase in diabetic rats fed with aqueous extracts were higher than in the normal diabetic group (p < 0.05). On the other hand, diabetic rats treated with the ethanol extract raised the activities of hepatic hexokinase and glucose-6-phosphate dehydrogenase (p < 0.05) only. The experiments provided evidence to support the antihyperglycemic effect of guava leaf extract and the health function of guava leaves against type 2 diabetes.

  19. Hyperspectral Imaging Coupled with Random Frog and Calibration Models for Assessment of Total Soluble Solids in Mulberries

    PubMed Central

    Zhao, Yan-Ru; Yu, Ke-Qiang; He, Yong

    2015-01-01

    Chemometrics methods coupled with hyperspectral imaging technology in visible and near infrared (Vis/NIR) region (380–1030 nm) were introduced to assess total soluble solids (TSS) in mulberries. Hyperspectral images of 310 mulberries were acquired by hyperspectral reflectance imaging system (512 bands) and their corresponding TSS contents were measured by a Brix meter. Random frog (RF) method was used to select important wavelengths from the full wavelengths. TSS values in mulberry fruits were predicted by partial least squares regression (PLSR) and least-square support vector machine (LS-SVM) models based on full wavelengths and the selected important wavelengths. The optimal PLSR model with 23 important wavelengths was employed to visualise the spatial distribution of TSS in tested samples, and TSS concentrations in mulberries were revealed through the TSS spatial distribution. The results declared that hyperspectral imaging is promising for determining the spatial distribution of TSS content in mulberry fruits, which provides a reference for detecting the internal quality of fruits. PMID:26451273

  20. Application FT-NIR in rapid estimation of soluble solids content of intact kiwifruits by reflectance mode

    NASA Astrophysics Data System (ADS)

    Ying, Yibin; Lu, Huishan; Fu, Xiaping; Liu, Yande; Xu, Huirong; Yu, Haiyan

    2005-11-01

    Nondestructive method of measuring soluble solids content (SSC) of kiwifruit was developed by Fourier transform near infrared (FT-NIR) reflectance and fiber optics. Also, the models describing the relationship between SSC and the NIR spectra of the fruit were developed and evaluated. To develop the models several different NIR reflectance spectra were acquired for each fruit from a commercial supermarket. Different spectra correction algorithms (standard normal variate (SNV), multiplicative signal correction (MSC)) were used in this work. The relationship between laboratory SSC and FT-NIR spectra of kiwifruits were analyzed via principle component regression (PCR) and partial least squares (PLS) regression method using TQ 6.2.1 quantitative software (Thermo Nicolet Co., USA). Models based on the different spectral ranges were compared in this research. The first derivative and second derivative were applied to all measured spectra to reduce the effects of sample size, light scattering, noise of instrument, etc. Different baseline correction methods were applied to improve the spectral data quality. Among them the second derivative method after baseline correction produced best noise removing capability and to obtain optimal calibration models. Total 480 NIR spectra were acquired from 120 kiwifruits and 90 samples were used to develop the calibration model, the rest samples were used to validate the model. Developed PLS model, which describes the relationship between SSC and NIR spectra, could predict SSC of 84 unknown samples with correlation coefficient of 0.9828 and SEP of 0.679 Brix.

  1. Characterization of acid-and pepsin-soluble collagens from spines and skulls of skipjack tuna (Katsuwonus pelamis).

    PubMed

    Yu, Di; Chi, Chang-Feng; Wang, Bin; Ding, Guo-Fang; Li, Zhong-Rui

    2014-09-01

    Acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from the spine (ASC-SP and PSC-SP) and skull (ASC-SK and PSC-SK) of the skipjack tuna, Katsuwonus pelamis, were successfully isolated and characterized. The yields of ASC-SP, PSC-SP, ASC-SK and PSC-SK were (2.47 ± 0.39)%, (5.62 ± 0.82)%, (3.57 ± 0.40)%, and (6.71 ± 0.81)%, respectively, on the basis of dry weight. The four collagens contained Gly (330.2-339.1 residues/1 000 residues) as the major amino acid, and their imino acid contents were between 168.8 and 178.2 residues/1 000 residues. Amino acid composition, SDS-PAGE, and FTIR investigations confirmed that ASC-SP and ASC-SK were mainly composed of type I collagen, and had higher contents of high-molecular weight cross-links than those of PSC-SK and PSC-SP. The FTIR investigation also certified all the collagens had triple helical structure. The denaturation temperatures of ASC-SK, PSC-SK, ASC-SP, and PSC-SP were 17.8, 16.6, 17.6, and 16.5 °C, respectively. All isolated collagens were soluble at acidic pH (1-5) and lost their solubilities when the NaCl concentration was above 2% (W/V). The isolated collagens from the spines and skulls of skipjack tuna could serve as an alternative source of collagens for further application in food, cosmetic, biomedical, and pharmaceutical industries.

  2. Solubility and partial molar volumes of naphthalene, phenanthrene, benzoic acid, and 2-methoxynaphthalene in supercritical carbon dioxide

    SciTech Connect

    Goenenc, Z.S.; Akman, U. |; Sunol, A.K.

    1995-07-01

    The effect of temperature, pressure, and supercritical fluid density on the retention and solubility in the mobile phase of solutes in supercritical fluid chromatography was investigated. New retention data for naphthalene, phenanthrene, benzoic acid, and 2-methoxynaphthalene were obtained as a function of pressure at different temperatures. Most of the data were taken near the critical region of the fluid phase where the anomalities such as enhanced solubility/selectivity and retrogate behavior are expected. These data were then used to compare two different approaches for modeling the pressure dependence of solute retention on the column. In these approaches, mobile-phase partial molar volumes of the solutes were determined either from bulk solubility data or from infinite-dilution fugacity coefficients. In both approaches, an integrated expression for the change of retention with pressure was utilized to explicitly reveal the nature of interactions between the stationary phase and the solute. The approach that utilizes the infinite-dilution fugacity coefficient predicts the pressure dependence of solute retention more accurately, especially for solutes that are substantially soluble in the mobile phase near the critical point of the mobile phase. Relationships between the pressure and temperature dependence of the solute solubility in the mobile phase and the retention of solutes on the column were also investigated.

  3. Understanding Particle Formation: Solubility of Free Fatty Acids as Polysorbate 20 Degradation Byproducts in Therapeutic Monoclonal Antibody Formulations.

    PubMed

    Doshi, Nidhi; Demeule, Barthélemy; Yadav, Sandeep

    2015-11-01

    The purpose of this work was to determine the aqueous solubilities at 2-8 °C of the major free fatty acids (FFAs) formed by polysorbate 20 (PS20) degradation and identify possible ways to predict, delay, or mitigate subsequent particle formation in monoclonal antibody (mAb) formulations. The FFA solubility limits at 2-8 °C were determined by titrating known amounts of FFA in monoclonal antibody formulations and identifying the FFA concentration leading to visible and subvisible particle formation. The solubility limits of lauric, myristic, and palmitic acids at 2-8 °C were 17 ± 1 μg/mL, 3 ± 1 μg/mL, and 1.5 ± 0.5 μg/mL in a formulation containing 0.04% (w/v) PS20 at pH 5.4 and >22 μg/mL, 3 ± 1 μg/mL, and 0.75 ± 0.25 μg/mL in a formulation containing 0.02% (w/v) PS20 at pH 6.0. For the first time, a 3D correlation between FFA solubility, PS20 concentration, and pH has been reported providing a rational approach for the formulator to balance these with regard to potential particle formation. The results suggest that the lower solubilities of the longer chain FFAs, generated from degradation of the stearate, palmitate, and myristate fraction of PS20, is the primary cause of seeding and subsequent FFA precipitation rather than the most abundant lauric acid. PMID:26419285

  4. J-aggregate formation of a water-soluble porphyrin in acidic aqueous media

    NASA Astrophysics Data System (ADS)

    Ohno, Osamu; Kaizu, Youkoh; Kobayashi, Hiroshi

    1993-09-01

    J aggregate of a water-soluble porphyrin, 5,10,15,20-tetra(4-sulfophenyl)porphyrin (H2TPPS44-), formed in acidified aqueous solutions, exhibits sharp and intense absorption bands at 491 and 707 nm. These characteristic transitions, J bands, are of linear oscillators polarized in the long axis of rodlike aggregate. The molecules in the aggregate stack so as to lift the degeneracy of the porphyrin planar oscillator excited states. Measurements of flow-induced linear dichroism, circular dichroism, magnetic circular dichroism, as well as polarized fluorescence excitation spectra provide evidence not only of linear oscillator character of the intense J band at 491 nm, but also of presence of another diffuse absorption band around at 420 nm polarized in the short axis of the aggregate, which is the counterpart of the 491 nm band of porphyrin Soret origin. Extrinsic circular dichroism is induced upon addition of L-tartaric acid or by mechanical swirling flow in the period of aggregate growth. Resonance Raman spectrum of the aggregate is rather similar to that of the monomeric diacid except the polarization. The observed shifts of Raman peaks to lower frequency are ascribed to a deformation of porphyrin moiety and/or hydrophobic interaction between component molecules in the aggregate. The sharp and intense J bands polarized in the long axis of aggregate cannot be well described without taking into account the participation of interporphyrin charge resonance excited states, whereas the broadbands polarized in the short axis are exclusively ascribed to exciton resonance excited states. The porphyrin J band is characterized as sustaining an exchange narrowing by fast migration of excitation over the whole system of chromophores in a linear array of the porphyrin planar oscillators in slipped face-to-face stacking.

  5. Restoration of Brain Acid Soluble Protein 1 Inhibits Proliferation and Migration of Thyroid Cancer Cells

    PubMed Central

    Guo, Run-Sheng; Yu, Yue; Chen, Jun; Chen, Yue-Yu; Shen, Na; Qiu, Ming

    2016-01-01

    Background: Brain acid soluble protein 1 (BASP1) is identified as a novel potential tumor suppressor in several cancers. However, its role in thyroid cancer has not been investigated yet. In the present study, the antitumor activities of BASP1 against the growth and migration of thyroid cancer cells were evaluated. Methods: BASP1 expression in thyroid cancer tissues and normal tissues were examined by immunohistochemical staining and the association between its expression and prognosis was analyzed. pcDNA-BASP1 carrying full length of BASP1 cDNA was constructed to restore the expression of BASP1 in thyroid cancer cell lines (BHT-101 and KMH-2). The cell proliferation in vitro and in vivo was evaluated by WST-1 assay and xenograft tumor models, respectively. Cell cycle distribution after transfection was analyzed using flow cytometry. Cell apoptosis after transfection was examined by annexin V/propidium iodide assay. The migration was examined using transwell assay. Results: BASP1 expression was abundant in normal tissues while it is significantly decreased in cancer tissues (P = 0.000). pcDNA-BASP1 restored the expression of BASP1 and significantly inhibited the growth of BHT-101 and KMH-2 cells as well as xenograft tumors in nude mice (P = 0.000). pcDNA-BASP1 induced G1 arrest and apoptosis in BHT-101 and KMH-2 cells. In addition, pcDNA-BASP1 significantly inhibited the cell migration. Conclusions: Downregulation of BASP1 expression may play a role in the tumorigenesis of thyroid cancer. Restoration of BASP1 expression exerted extensive antitumor activities against growth and migration of thyroid cancer cells, which suggested that BASP1 gene might act as a potential therapeutic agent for the treatment of thyroid cancer. PMID:27270539

  6. Facile synthesis of highly efficient and recyclable magnetic solid acid from biomass waste.

    PubMed

    Liu, Wu-Jun; Tian, Ke; Jiang, Hong; Yu, Han-Qing

    2013-01-01

    In this work, sawdust, a biomass waste, is converted into a magnetic porous carbonaceous (MPC) solid acid catalyst by an integrated fast pyrolysis-sulfonation process. The resultant magnetic solid acid has a porous structure with high surface area of 296.4 m(2) g(-1), which can be attributed to the catalytic effect of Fe. The catalytic activity and recyclability of the solid acid catalyst are evaluated during three typical acid-catalyzed reactions: esterification, dehydration, and hydrolysis. The favorable catalytic performance in all three reactions is attributed to the acid's high strength with 2.57 mmol g(-1) of total acid sites. Moreover, the solid acid can be reused five times without a noticeable decrease in catalytic activity, indicating the stability of the porous carbon (PC)-sulfonic acid group structure. The findings in the present work offer effective alternatives for environmentally friendly utilization of abundant biomass waste. PMID:23939253

  7. Facile synthesis of highly efficient and recyclable magnetic solid acid from biomass waste

    NASA Astrophysics Data System (ADS)

    Liu, Wu-Jun; Tian, Ke; Jiang, Hong; Yu, Han-Qing

    2013-08-01

    In this work, sawdust, a biomass waste, is converted into a magnetic porous carbonaceous (MPC) solid acid catalyst by an integrated fast pyrolysis-sulfonation process. The resultant magnetic solid acid has a porous structure with high surface area of 296.4 m2 g-1, which can be attributed to the catalytic effect of Fe. The catalytic activity and recyclability of the solid acid catalyst are evaluated during three typical acid-catalyzed reactions: esterification, dehydration, and hydrolysis. The favorable catalytic performance in all three reactions is attributed to the acid's high strength with 2.57 mmol g-1 of total acid sites. Moreover, the solid acid can be reused five times without a noticeable decrease in catalytic activity, indicating the stability of the porous carbon (PC)-sulfonic acid group structure. The findings in the present work offer effective alternatives for environmentally friendly utilization of abundant biomass waste.

  8. Facile synthesis of highly efficient and recyclable magnetic solid acid from biomass waste

    PubMed Central

    Liu, Wu-Jun; Tian, Ke; Jiang, Hong; Yu, Han-Qing

    2013-01-01

    In this work, sawdust, a biomass waste, is converted into a magnetic porous carbonaceous (MPC) solid acid catalyst by an integrated fast pyrolysis–sulfonation process. The resultant magnetic solid acid has a porous structure with high surface area of 296.4 m2 g−1, which can be attributed to the catalytic effect of Fe. The catalytic activity and recyclability of the solid acid catalyst are evaluated during three typical acid-catalyzed reactions: esterification, dehydration, and hydrolysis. The favorable catalytic performance in all three reactions is attributed to the acid's high strength with 2.57 mmol g−1 of total acid sites. Moreover, the solid acid can be reused five times without a noticeable decrease in catalytic activity, indicating the stability of the porous carbon (PC)–sulfonic acid group structure. The findings in the present work offer effective alternatives for environmentally friendly utilization of abundant biomass waste. PMID:23939253

  9. Solubility of carbon dioxide in acetone and propionic acid at temperatures between 298 K and 333 K

    SciTech Connect

    Adrian, T.; Maurer, G.

    1997-07-01

    The solubility of carbon dioxide in organic solvents acetone and propionic acid has been measured with an analytical method. The composition and the density of the liquid phase in the binary vapor-liquid equilibrium have been investigated at (313 and 333) K (for the system carbon dioxide + acetone) and at (298, 313, and 333) K (for the system carbon dioxide + propionic acid) at pressures up the binary critical pressure. The experimental results for the phase equilibrium have been correlated with the Peng-Robinson EOS applying several mixing rules.

  10. Lactic acid fermentation stimulated iron absorption by Caco-2 cells is associated with increased soluble iron content in carrot juice.

    PubMed

    Bergqvist, Sharon W; Andlid, Thomas; Sandberg, Ann-Sofie

    2006-10-01

    An in vitro digestion/Caco-2 cell model was applied to explore the impact of lactic acid (LA) fermentation by Lactobacillus pentosus FSC1 and Leuconostoc mesenteroides FSC2 on the Fe bioavailability of carrot juice. The redox state of Fe in fermented carrot juice was also assessed as a crucial factor for absorption. LA fermentation was shown to improve mineral solubility to different extents at simulated physiological conditions: Mn (2-fold); Fe (1.5-1.7-fold); Zn (1.2-fold); Cu (1-fold). Soluble Fe2+ was increased about 16-fold by LA fermentation, and about one third of the Fe2+ remained soluble after in vitro digestion (about 4-5-fold higher than in fresh juice). Data on cell-line studies showed a 4-fold increase in the efficiency of Fe uptake, but not in transepithelial transfer by Caco2 cells, as a result of fermentation. The increases in Fe2+ level and the efficiency of cellular Fe uptake were strain-dependent. To sum up the effect on both Fe solubility and cellular uptake efficiency, the amount of cellularly absorbed Fe from Ln. mesenteroides FSC2-fermented juice was about 20 % higher than that from L. pentosus FSC1-fermented juice (22.7 v. 19.2 microg/l juice per mg protein). To conclude, LA fermentation enhanced Fe absorption by Caco-2 cells from carrot juice because of increases in not only Fe solubility after digestion, but also the efficiency of cellular Fe uptake. The fermentation-improved efficiency of Fe uptake was possibly due to the increased level of soluble Fe2+ rather than a being a strain-specific event.

  11. Production of Jatropha biodiesel fuel over sulfonic acid-based solid acids.

    PubMed

    Chen, Shih-Yuan; Lao-Ubol, Supranee; Mochizuki, Takehisa; Abe, Yohko; Toba, Makoto; Yoshimura, Yuji

    2014-04-01

    Sulfonic acid-functionalized platelet SBA-15 mesoporous silica with an acid capacity of 2.44mmol H(+) g-cat(-1) (shortly termed 15SA-SBA-15-p) was one-pot synthesized by co-condensation method. When applied as solid acid catalyst in synthesis of Jatropha biodiesel fuel (BDF), the 15SA-SBA-15-p catalyst showed higher activity and resistances to water and free fatty acid (FFA) than commercial sulfonic resins of Amberlyst-15 and SAC-13. For the continuous Jatropha BDF production, a steady 75-78wt% of fatty acid methyl ester (FAME) content was obtained over 15SA-SBA-15-p catalyst at 150°C for 75h, whereas the Amberlyst-15 and SAC-13 catalysts were quickly deactivated due to the decomposition of thermally unstable framework and serious leaching of sulfonic acids. More importantly, the quality, stability and cold flow characteristic of Jatropha BDF synthesized by 15SA-SBA-15-p catalyst were better than those synthesized by Amberlyst-15 and SAC-13 catalysts, making the blending with petro-diesel an easy task.

  12. [Determination of soluble solids content in Nanfeng Mandarin by Vis/NIR spectroscopy and UVE-ICA-LS-SVM].

    PubMed

    Sun, Tong; Xu, Wen-Li; Hu, Tian; Liu, Mu-Hua

    2013-12-01

    The objective of the present research was to assess soluble solids content (SSC) of Nanfeng mandarin by visible/near infrared (Vis/NIR) spectroscopy combined with new variable selection method, simplify prediction model and improve the performance of prediction model for SSC of Nanfeng mandarin. A total of 300 Nanfeng mandarin samples were used, the numbers of Nanfeng mandarin samples in calibration, validation and prediction sets were 150, 75 and 75, respectively. Vis/NIR spectra of Nanfeng mandarin samples were acquired by a QualitySpec spectrometer in the wavelength range of 350-1000 nm. Uninformative variables elimination (UVE) was used to eliminate wavelength variables that had few information of SSC, then independent component analysis (ICA) was used to extract independent components (ICs) from spectra that eliminated uninformative wavelength variables. At last, least squares support vector machine (LS-SVM) was used to develop calibration models for SSC of Nanfeng mandarin using extracted ICs, and 75 prediction samples that had not been used for model development were used to evaluate the performance of SSC model of Nanfeng mandarin. The results indicate t hat Vis/NIR spectroscopy combinedwith UVE-ICA-LS-SVM is suitable for assessing SSC o f Nanfeng mandarin, and t he precision o f prediction ishigh. UVE--ICA is an effective method to eliminate uninformative wavelength variables, extract important spectral information, simplify prediction model and improve the performance of prediction model. The SSC model developed by UVE-ICA-LS-SVM is superior to that developed by PLS, PCA-LS-SVM or ICA-LS-SVM, and the coefficient of determination and root mean square error in calibration, validation and prediction sets were 0.978, 0.230%, 0.965, 0.301% and 0.967, 0.292%, respectively.

  13. Ultraviolet-visible transmittance techniques for rapid analysis of sugar content and soluble solids content of fresh navel orange juices

    NASA Astrophysics Data System (ADS)

    Liu, Yande; Ouyang, Aiguo; Luo, Ji; Ying, Yibin

    2005-11-01

    Sugar content (SC) and soluble solids content (SSC) are very important factors of navel orange internal quality and can be measured non-invasively by ultraviolet-visible spectroscopy techniques. The feasibility and methods of ultraviolet-visible spectroscopic techniques for rapid quantifying SC and SSC of navel orange fresh juices was investigated by its spectral transmittance. A total 55 juice samples were used to develop the calibration and prediction models. Different spectra correction algorithms (constant, multiplicative signal correction (MSC) and standard normal variate (SNV) were compared in our work. Three different kinds of mathematical spectra treatments (original, first derivative and second derivative) of spectra in the range of 200-800 nm and two kinds of reference standards were also investigated. Three kinds of models including partial least square regression (PLSR), stepwise multiple linear regression (SMLR) and principle component regression (PCR) were evaluated for the determination of SC and SSC in navel orange juice. Calibration models based on the different spectral ranges were also compared. Performance of different models was assessed in terms of root mean square errors of prediction (RMSEP) and correlation coefficient (r) of prediction set of samples. The correlation coefficients of calibration models for SC and SSC were 0.965 and 0.961, the correlation coefficients of prediction models for SC and SSC were 0.857 and 0.888, and the corresponding RMSEP were 0.562 and 0.492 respectively. The results show that ultraviolet-visible transmittance technique is a feasible method for non-invasive estimation of fruit juice SC and SSC.

  14. Proton play in the formation of low molecular weight chitosan (LWCS) by hydrolyzing chitosan with a carbon based solid acid.

    PubMed

    Krishnan, R Akhil; Deshmukh, Pranjal; Agarwal, Siddharth; Purohit, Poorvi; Dhoble, Deepa; Waske, Prashant; Khandekar, Dileep; Jain, Ratnesh; Dandekar, Prajakta

    2016-10-20

    Low molecular weight chitosan (LWCS) constitute a special class of value added chemicals that are primarily obtained from crustacean shells, which are the main water pollutants from crabs and shrimp processing centers. Unlike chitin and chitosan, LWCS possess improved solubility in water and aqueous solutions, making them widely applicable in numerous fields ranging from drug delivery to waste water treatment. Among the methods employed for their production, chemical breakdown by strong liquid acids has yielded good success. However, this method is met with severe concerns arising from the harsh nature of liquid acids, which may corrode the reactors for commercial synthesis, and their limited reusability. The physical methods like ultrasound and microwave are energy intensive in nature, while the enzymatic methods are expensive and offers limited scope for reuse. We have attempted to overcome these problems by employing carbon based solid acid (CSA) for hydrolyzing chitosan to LWCS. CSA can be easily produced using activated carbon, a cost-effective and easily available raw material. Reactions were carried out between chitosan and CSA in a hydrothermal glass reactor and the products, separated by cold centrifugation, were purified and dried. The dried products were characterized for their molecular weight and solubility. Results indicated more than ten-fold decrease in the molecular weight of chitosan and the product exhibited water solubility. The CSA could be used upto four times, without regeneration, to give a consistent quality product. The aqueous solution of resulting LWCS exhibited a pH of 6.03±0.11, as against the acidic pH range of solutions of commercially available LWCS, indicating its suitability for biomedical applications. Our investigation facilitates a 'green approach' that may be employed for commercial production of value added chemicals from waste products of marine industry. PMID:27474584

  15. Soluble CD44 inhibits melanoma tumor growth by blocking cell surface CD44 binding to hyaluronic acid.

    PubMed

    Ahrens, T; Sleeman, J P; Schempp, C M; Howells, N; Hofmann, M; Ponta, H; Herrlich, P; Simon, J C

    2001-06-01

    Proteolytic cleavage of the extracellular domain of CD44 from the surface of cells has been observed recently in different cell types. In cell culture supernatants of human melanoma cell lines a 70 kDa soluble CD44 protein (solCD44) was detected at concentrations of 250-300 ng/ml. Protease inhibitor studies revealed that serine proteases and metalloproteases are involved in the cleavage of CD44 from the surface of melanoma cells. To analyse a possible function of soluble CD44 a human malignant melanoma cell line was stably transfected with cDNAs encoding either wild type soluble CD44s or mutated forms with defective HA binding properties (CD44sR41A and CD44sR150A/R154A). Soluble CD44s almost completely inhibited hyaluronic acid binding by melanoma cells, whereas soluble CD44 mutated in the HA binding domain had no effect. When cultivated on hyaluronic acid, melanoma cell proliferation was induced by 30% for both the parental and the control transfected cells. This increase in proliferation was blocked completely in solCD44s-secreting transfectants, whereas solCD44sR41A and solCD44sR150A/R154A-secreting cells again showed hyaluronic acid-induced cell proliferation. These cell lines were subcutaneously injected into MF1 nu/nu mice to compare their growth as tumors in vivo. Compared to tumors derived from parental and control transfected cells, we observed a dramatic reduction of primary tumor growth with solCD44s expressing MM cells. Transfectants expressing solCD44s mutated in the HA binding domain in contrast developed fast-growing primary tumors. These results provide strong evidence that direct solCD44 interactions with hyaluronic acid interfere competitively with processes induced by hyaluronic acid binding to surface CD44. Autocrine, or drug-induced secretion of solCD44 by human melanoma cells may thus exert potent antitumoral effects in vivo. PMID:11423990

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

    PubMed

    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.

  17. Atmospheric transport of mineral dust from the Indo-Gangetic Plain: Temporal variability, acid processing, and iron solubility

    NASA Astrophysics Data System (ADS)

    Srinivas, Bikkina; Sarin, M. M.; Rengarajan, R.

    2014-08-01

    transport of chemical constituents from the Indo-Gangetic Plain (IGP) to the Bay of Bengal is a conspicuous seasonal feature that occurs during the late NE-monsoon (December-March). With this perspective, aerosol composition and abundance of mineral dust have been studied during November 2009 to March 2010 from a sampling site (Kharagpur: 22.3°N, 87.3°E) in the IGP, representing the atmospheric outflow to the Bay of Bengal. The chemical composition of PM2.5 suggests the dominance of nss-SO42- (6.9-24.3 µg m-3); whereas the abundance of mineral dust varied from 3 to 18 µg m-3. The concentration of aerosol iron (FeTot) and its fractional solubility (Fews % = Fews/FeTot *100, where Fews is the water-soluble fraction of FeTot) varied from 60 to 1144 ng m-3 and from 6.7 to 26.5%, respectively. A striking similarity in the temporal variability of total inorganic acidity (TIA = NO3- + nss-SO42-) and Fews (%) provides evidence for acid processing of mineral dust (alluvium) during atmospheric transport from the IGP. The contribution of TIA to water-soluble inorganic species [(nss-SO42- + NO3-)/ΣWSIS], mass ratios of Ca/Al and Fe/Al, and abundance of dust (%) and Fews (%) in the IGP-outflow are similar to the aerosol composition over the Bay of Bengal. With the rapid increase in anthropogenic activities over south and south-east Asia, the enhanced fractional solubility of aerosol iron (attributed to acid processing of mineral dust) has implications to further increase in the air-sea deposition of Fe to the Ocean surface.

  18. Thermochemical comparison of Argonne premium coal samples with model solid acids

    SciTech Connect

    Arnett, E.M.; Hutchinson, B.J.; Gumkowski, M.; Liu, Q.

    1988-01-01

    This presentation is a summary of results acquired over the last five years using the heats of interaction of a series of bases with various solid acids as a means for classifying them. A sulfonic acid resin provides a solid model for Broensted acidity. Silica is a model solid for hydrogen bonding interactions and several grades of graphitized carbon black are an excellent model for van der Waals/dispersion force interactions. Heats of interaction of the series of bases with several types of Argonne premium coals compared with those for the model solids and serve as a means for coal classification.

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

    PubMed

    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. PMID:26797927

  20. Consequences of acid strength for isomerization and elimination catalysis on solid acids.

    PubMed

    Macht, Josef; Carr, Robert T; Iglesia, Enrique

    2009-05-13

    We address here the manner in which acid catalysis senses the strength of solid acids. Acid strengths for Keggin polyoxometalate (POM) clusters and zeolites, chosen because of their accurately known structures, are described rigorously by their deprotonation energies (DPE). Mechanistic interpretations of the measured dynamics of alkane isomerization and alkanol dehydration are used to obtain rate and equilibrium constants and energies for intermediates and transition states and to relate them to acid strength. n-Hexane isomerization rates were limited by isomerization of alkoxide intermediates on bifunctional metal-acid mixtures designed to maintain alkane-alkene equilibrium. Isomerization rate constants were normalized by the number of accessible protons, measured by titration with 2,6-di-tert-butylpyridine during catalysis. Equilibrium constants for alkoxides formed by protonation of n-hexene increased slightly with deprotonation energies (DPE), while isomerization rate constants decreased and activation barriers increased with increasing DPE, as also shown for alkanol dehydration reactions. These trends are consistent with thermochemical analyses of the transition states involved in isomerization and elimination steps. For all reactions, barriers increased by less than the concomitant increase in DPE upon changes in composition, because electrostatic stabilization of ion-pairs at the relevant transition states becomes more effective for weaker acids, as a result of their higher charge density at the anionic conjugate base. Alkoxide isomerization barriers were more sensitive to DPE than for elimination from H-bonded alkanols, the step that limits 2-butanol and 1-butanol dehydration rates; the latter two reactions showed similar DPE sensitivities, despite significant differences in their rates and activation barriers, indicating that slower reactions are not necessarily more sensitive to acid strength, but instead reflect the involvement of more unstable organic

  1. Water-soluble organic carbon, dicarboxylic acids, ketoacids, and α-dicarbonyls in the tropical Indian aerosols

    NASA Astrophysics Data System (ADS)

    Pavuluri, Chandra Mouli; Kawamura, Kimitaka; Swaminathan, T.

    2010-06-01

    Tropical aerosol (PM10) samples (n = 49) collected from southeast coast of India were studied for water-soluble dicarboxylic acids (C2-C12), ketocarboxylic acids (C2-C9), and α-dicarbonyls (glyoxal and methylglyoxal), together with analyses of total carbon (TC) and water-soluble organic carbon (WSOC). Their distributions were characterized by a predominance of oxalic acid followed by terephthalic (t-Ph), malonic, and succinic acids. Total concentrations of diacids (227-1030 ng m-3), ketoacids (16-105 ng m-3), and dicarbonyls (4-23 ng m-3) are comparative to those from other Asian megacities such as Tokyo and Hong Kong. t-Ph acid was found as the second most abundant diacid in the Chennai aerosols. This feature has not been reported previously in atmospheric aerosols. t-Ph acid is most likely derived from the field burning of plastics. Water-soluble diacids were found to contribute 0.4%-3% of TC and 4%-11% of WSOC. Based on molecular distributions and backward air mass trajectories, we found that diacids and related compounds in coastal South Indian aerosols are influenced by South Asian and Indian Ocean monsoons. Organic aerosols are also suggested to be significantly transported long distances from North India and the Middle East in early winter and from Southeast Asia in late winter, but some originate from photochemical reactions over the Bay of Bengal. In contrast, the Arabian Sea, Indian Ocean, and South Indian continent are suggested as major source regions in summer. We also found daytime maxima of most diacids, except for C9 and t-Ph acids, which showed nighttime maxima in summer. Emissions from marine and terrestrial plants, combined with land/sea breezes and in situ photochemical oxidation, are suggested especially in summer as an important factor that controls the composition of water-soluble organic aerosols over the southeast coast of India. Regional emissions from anthropogenic sources are also important in megacity Chennai, but their influence is

  2. A novel osmotic pump-based controlled delivery system consisting of pH-modulated solid dispersion for poorly soluble drug flurbiprofen: in vitro and in vivo evaluation.

    PubMed

    Li, Shujuan; Wang, Xiaoyu; Wang, Yingying; Zhao, Qianqian; Zhang, Lina; Yang, Xinggang; Liu, Dandan; Pan, Weisan

    2015-01-01

    In this study, a novel controlled release osmotic pump capsule consisting of pH-modulated solid dispersion for poorly soluble drug flurbiprofen (FP) was developed to improve the solubility and oral bioavailability of FP and to minimize the fluctuation of plasma concentration. The pH-modulated solid dispersion containing FP, Kollidon® 12 PF and Na2CO3 at a weight ratio of 1/4.5/0.02 was prepared using the solvent evaporation method. The osmotic pump capsule was assembled by semi-permeable capsule shell of cellulose acetate (CA) prepared by the perfusion method. Then, the solid dispersion, penetration enhancer, and suspending agents were tableted and filled into the capsule. Central composite design-response surface methodology was used to evaluate the influence of factors on the responses. A second-order polynomial model and a multiple linear model were fitted to correlation coefficient of drug release profile and ultimate cumulative release in 12 h, respectively. The actual response values were in good accordance with the predicted ones. The optimized formulation showed a complete drug delivery and zero-order release rate. Beagle dogs were used to be conducted in the pharmacokinetic study. The in vivo study indicated that the relative bioavailability of the novel osmotic pump system was 133.99% compared with the commercial preparation. The novel controlled delivery system with combination of pH-modulated solid dispersion and osmotic pump system is not only a promising strategy to improve the solubility and oral bioavailability of poorly soluble ionizable drugs but also an effective way to reduce dosing frequency and minimize the plasma fluctuation.

  3. Amino acids as co-amorphous stabilizers for poorly water-soluble drugs--Part 2: molecular interactions.

    PubMed

    Löbmann, Korbinian; Laitinen, Riikka; Strachan, Clare; Rades, Thomas; Grohganz, Holger

    2013-11-01

    The formation of co-amorphous drug-drug mixtures has proved to be a powerful approach to stabilize the amorphous form and at the same time increase the dissolution of poorly water-soluble drugs. Molecular interactions in these co-amorphous formulations can play a crucial role in stabilization and dissolution enhancement. In this regard, Fourier-transform infrared spectroscopy (FTIR) is a valuable tool to analyze the molecular near range order of the compounds in the co-amorphous mixtures. In this study, several co-amorphous drugs--low molecular weight excipient blends--have been analyzed with FTIR spectroscopy. Molecular interactions of the drugs carbamazepine and indomethacin with the amino acids arginine, phenylalanine, and tryptophan were investigated. The amino acids were chosen from the biological target site of both drugs and prepared as co-amorphous formulations together with the drugs by vibrational ball milling. A detailed analysis of the FTIR spectra of these formulations revealed specific peak shifts in the vibrational modes of functional groups of drug and amino acid, as long as one amino acid from the biological target site was present in the blends. These peak shifts indicate that the drugs formed specific molecular interactions (hydrogen bonding and π-π interactions) with the amino acids. In the drug-amino acid mixtures that contained amino acids which were not present at the biological target site, no such interactions were identified. This study shows the potential of amino acids as small molecular weight excipients in co-amorphous formulations to stabilize the amorphous form of a poorly water-soluble drug through strong and specific molecular interactions with the drug.

  4. Apparent ileal amino acid digestibility of reduced-oil distillers dried grains with solubles fed to broilers from 23 to 31 days of age.

    PubMed

    Dozier, W A; Perryman, K R; Hess, J B

    2015-03-01

    An experiment was conducted using male Ross×Ross 708 broiler chicks to determine the effect of oil extraction from corn distillers dried grains with solubles on apparent ileal amino acid digestibility from 23 to 31 d of age. On an as-fed basis, ether extract concentrations were determined as 5.4% (L-distillers dried grains with solubles), 7.9% (M-distillers dried grains with solubles), and 10.5% (H-distillers dried grains with solubles) for the 3 experimental distillers dried grains with solubles sources. Prior to experimentation, each sample (H-distillers dried grains with solubles (control), M-distillers dried grains with solubles and L-distillers dried grains with solubles) was analyzed on an as-fed basis for crude protein (29.2, 27.6, and 27.9%), starch (4.4, 5.2, and 6.1%), neutral detergent fiber (29.5, 33.2, and 29.9%), and total dietary fiber (31.4, 36.6, and 33.6 %). Four hundred and thirty-two male chicks (12 birds per cage; 0.04 m2 per bird) were randomly assigned to 36 battery grower cages. Broilers were fed one of 3 semi-purified diets, which were comprised of 76% L-distillers dried grains with solubles, M- distillers dried grains with solubles, or H-distillers dried grains with solubles as the sole amino acid source from 23 to 31 d of age. Apparent ileal amino acid digestibility coefficients were negatively affected (P<0.05) by oil extraction for Met (0.722, 0.788, and 0.791), Lys (0.504, 0.510, and 0.552), Thr (0.563, 0.566, and 0.612), Trp (0.708, 0.733, and 0.767), and Arg (0.762, 0.776, and 0.799) for L-distillers dried grains with solubles, M-distillers dried grains with solubles, and H-distillers dried grains with solubles, respectively. Conversely, no differences in apparent amino acid coefficients were reported for Ile, Leu, and Val. These results indicated that L-distillers dried grains with solubles had lower apparent amino acid digestibility coefficients for Met, Lys, Thr, Trp, and Arg compared with H-distillers dried grains with

  5. Seasonal and longitudinal distributions of atmospheric water-soluble dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls over the North Pacific

    NASA Astrophysics Data System (ADS)

    Bikkina, Srinivas; Kawamura, Kimitaka; Imanishi, Katsuya; Boreddy, S. K. R.; Nojiri, Yukihiro

    2015-05-01

    In order to assess the seasonal variability of atmospheric abundances of dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls over the North Pacific and Sea of Japan, aerosol samples were collected along the longitudinal transacts during six cruises between Canada and Japan. The back trajectory analyses indicate that aerosol samples collected in winter and spring are influenced by the East Asian outflow, whereas summer and fall samples are associated with the pristine maritime air masses. Molecular distributions of water-soluble organics in winter and spring samples show the predominance of oxalic acid (C2) followed by succinic (C4) and malonic acids (C3). In contrast, summer and fall marine aerosols are characterized by the predominance of C3 over C4. Concentrations of dicarboxylic acids were higher over the Sea of Japan than the North Pacific. With a lack of continental outflow, higher concentrations during early summer are ascribed to atmospheric oxidation of organic precursors associated with high biological activity in the North Pacific. This interpretation is further supported by the high abundances of azelaic acid, which is a photochemical oxidation product of biogenic unsaturated fatty acids, over the Bering Sea in early summer when surface waters are characterized by high biological productivity. We found higher ratios of oxalic acid to pyruvic and glyoxylic acids (C2/Pyr and C2/ωC2) and glyoxal and methylglyoxal (C2/Gly and C2/MeGly) in summer and fall than in winter and spring, suggesting a production of C2 from the aqueous-phase oxidation of oceanic isoprene. In this study, dicarboxylic acids account for 0.7-38% of water-soluble organic carbon.

  6. Effect of CMC Molecular Weight on Acid-Induced Gelation of Heated WPI-CMC Soluble Complex.

    PubMed

    Huan, Yan; Zhang, Sha; Vardhanabhuti, Bongkosh

    2016-02-01

    Acid-induced gelation properties of heated whey protein isolate (WPI) and carboxymethylcellulose (CMC) soluble complex were investigated as a function of CMC molecular weight (270, 680, and 750 kDa) and concentrations (0% to 0.125%). Heated WPI-CMC soluble complex with 6% protein was made by heating biopolymers together at pH 7.0 and 85 °C for 30 min and diluted to 5% protein before acid-induced gelation. Acid-induced gel formed from heated WPI-CMC complexes exhibited increased hardness and decreased water holding capacity with increasing CMC concentrations but gel strength decreased at higher CMC content. The highest gel strength was observed with CMC 750 k at 0.05%. Gels with low CMC concentration showed homogenous microstructure which was independent of CMC molecular weight, while increasing CMC concentration led to microphase separation with higher CMC molecular weight showing more extensive phase separation. When heated WPI-CMC complexes were prepared at 9% protein the acid gels showed improved gel hardness and water holding capacity, which was supported by the more interconnected protein network with less porosity when compared to complexes heated at 6% protein. It is concluded that protein concentration and biopolymer ratio during complex formation are the major factors affecting gel properties while the effect of CMC molecular weight was less significant.

  7. Strategies to improve the solubility and stability of stilbene antioxidants: a comparative study between cyclodextrins and bile acids.

    PubMed

    Silva, Filomena; Figueiras, Ana; Gallardo, Eugenia; Nerín, Cristina; Domingues, Fernanda C

    2014-02-15

    Aiming at the development of an active food packaging, the goal of this study was to increase stilbenes (resveratrol (RV), pterostilbene (PT) and pinosylvin (PS)) aqueous solubility and stability using hydropropyl-cyclodextrins (HP-CDs) and bile salts. To evaluate stilbene concentration, an HPLC-DAD method was validated. Stilbene solubility was improved by the formation of inclusion complexes and micellar systems with higher solubility values obtained for the inclusion complexes with cyclodextrins. Inclusion complexes revealed a 1:1 stoichiometry for RV and PT and a 1:2 for PS. Solid state characterisation was carried out using X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry. (1)H NMR studies were also performed to characterise the prepared complexes. Photostability studies revealed that CDs were able to increase stilbene photostability at 4 °C. This work showed that stable stilbene solutions can be achieved using hydroxypropyl-CDs, contributing for their incorporation in several materials for the food and pharmaceutical industries.

  8. [Study on solid dispersion of precipitated calcium carbonate-based oleanolic acid].

    PubMed

    Yan, Hong-mei; Zhang, Zhen-hai; Jia, Xiao-bin; Jiang, Yan-rong; Sun, E

    2015-05-01

    Oleanolic acid-precipitated calcium carbonate solid dispersion was prepared by using solvent evaporation method. The microscopic structure and physicochemical properties of solid dispersion were analyzed using differential scanning calorimetry and scanning electron microscopy (SEM). And its in vitro release also was investigated. The properties of the precipitated calcium carbonate was studied which was as a carrier of oleanolic acid solid dispersion. Differential scanning calorimetry analysis suggested that oleanolic acid may be present in solid dispersion as amorphous substance. The in vitro release determination results of oleanolic acid-precipitated calcium carbonate (1: 5) solid dispersion showed accumulated dissolution rate of.oleanolic acid was up to 90% at 45 min. Accelerating experiment showed that content and in vitro dissolution of oleanolic acid solid dispersion did not change after storing over 6 months. The results indicated that in vitro dissolution of oleanolic acid was improved greatly by the solid dispersion with precipitated calcium carbonate as a carrier. The solid dispersion is a stabilizing system which has actual applied value.

  9. Acid-base site detection and mapping on solid surfaces by Kelvin force microscopy (KFM).

    PubMed

    Gouveia, Rubia F; Bernardes, Juliana S; Ducati, Telma R D; Galembeck, Fernando

    2012-12-01

    Electrostatic potential at the surface of acidic or basic solids changes under higher relative humidity (RH), as determined by using Kelvin force microscopy (KFM). The potential on acid surfaces becomes more negative as the water vapor pressure increases, while it becomes more positive on basic solids. These results verify the following hypothesis: OH(-) or H(+) ions associated with atmospheric water ion clusters are selectively adsorbed on solid surfaces, depending on the respective Brønsted acid or base character. Therefore, Kelvin microscopy, under variable humidity, is a rigorous but convenient alternative to determine the acid-base character of solid surfaces, with a great advantage: it uses only one amphoteric and simple reagent to determine both the acid and base sites. Moreover, this technique provides information on the spatial distribution of acid-base sites, which is currently inaccessible to any other method.

  10. Crystallization of a salt of a weak organic acid and base: solubility relations, supersaturation control and polymorphic behavior.

    PubMed

    Jones, H P; Davey, R J; Cox, B G

    2005-03-24

    Control of crystallization processes for organic salts is of importance to the pharmaceutical industry as many active pharmaceutical materials are marketed as salts. In this study, a method for estimating the solubility product of a salt of a weak acid and weak base from measured pH-solubility data is described for the first time. This allows calculation of the supersaturation of solutions at known pH. Ethylenediammonium 3,5-dinitrobenzoate is a polymorphic organic salt. A detailed study of the effects of pH, supersaturation, and temperature of crystallization on the physical properties of this salt shows that the desired polymorph may be produced by appropriate selection of the pH and supersaturation of crystallization. Crystal morphology is also controlled by these crystallization conditions.

  11. High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

    SciTech Connect

    Shi, Wei; Han, Shijiao; Huang, Wei; Yu, Junsheng

    2015-01-26

    High mobility organic field-effect transistors (OFETs) by inserting water-soluble deoxyribonucleic acid (DNA) buffer layer between electrodes and pentacene film through spray coating process were fabricated. Compared with the OFETs incorporated with DNA in the conventional organic solvents of ethanol and methanol: water mixture, the water-soluble DNA based OFET exhibited an over four folds enhancement of field-effect mobility from 0.035 to 0.153 cm{sup 2}/Vs. By characterizing the surface morphology and the crystalline structure of pentacene active layer through atomic force microscope and X-ray diffraction, it was found that the adoption of water solvent in DNA solution, which played a key role in enhancing the field-effect mobility, was ascribed to both the elimination of the irreversible organic solvent-induced bulk-like phase transition of pentacene film and the diminution of a majority of charge trapping at interfaces in OFETs.

  12. Polymorphism in sulfadimidine/4-aminosalicylic acid cocrystals: solid-state characterization and physicochemical properties.

    PubMed

    Grossjohann, Christine; Serrano, Dolores R; Paluch, Krzysztof J; O'Connell, Peter; Vella-Zarb, Liana; Manesiotis, Panagiotis; Mccabe, Thomas; Tajber, Lidia; Corrigan, Owen I; Healy, Anne Marie

    2015-04-01

    Polymorphism of crystalline drugs is a common phenomenon. However, the number of reported polymorphic cocrystals is very limited. In this work, the synthesis and solid-state characterization of a polymorphic cocrystal composed of sulfadimidine (SD) and 4-aminosalicylic acid (4-ASA) is reported for the first time. By liquid-assisted milling, the SD:4-ASA 1:1 form I cocrystal, the structure of which has been previously reported, was formed. By spray drying, a new polymorphic form (form II) of the SD:4-ASA 1:1 cocrystal was discovered which could also be obtained by solvent evaporation from ethanol and acetone. Structure determination of the form II cocrystal was calculated using high-resolution X-ray powder diffraction. The solubility of the SD:4-ASA 1:1 cocrystal was dependent on the pH and predicted by a model established for a two amphoteric component cocrystal. The form I cocrystal was found to be thermodynamically more stable in aqueous solution than form II, which showed transformation to form I. Dissolution studies revealed that the dissolution rate of SD from both cocrystals was enhanced when compared with a physical equimolar mixture and pure SD. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:1385-1398, 2015.

  13. Fatty acid, cholesterol and fat-soluble vitamin composition of wild and captive freshwater crayfish (Astacus leptodactylus).

    PubMed

    Harlioglu, A Gül; Aydin, S; Yilmaz, O

    2012-02-01

    The proximate analysis (dry matter, protein, fat and ash), cholesterol, fatty acid and fat-soluble vitamin compositions of the tail muscle of wild caught and captive crayfish (Astacus leptodactylus) were investigated. Captive crayfish contained higher moisture and fat content than wild crayfish. In contrast, wild crayfish contained a higher level of crude protein, ash and n-3 polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) than captive crayfish. Arachidonic acid (C20:4 n-6) was the major n-6 PUFA in wild A. leptodactylus, and linoleic acid (C18:2 n-6) was the major n-6 PUFA in captive A. leptodactylus. The percentages of total saturated fatty acids (SFA), PUFA, and n-3/n-6 ratio were higher in wild crayfish and total monounsaturated fatty acids (MUFA) were lower. Although differences existed between wild and captive crayfish in vitamins A (p < 0.001), δ-Tocopherol (p < 0.001), α-Tocopherol acetate (p < 0.05), no differences were found in vitamins D(2), D(3), α- Tocopherol and K (p > 0.05). The differences may be originated from the diet provided to captive crayfish. Since wild A. leptodactylus contained higher n-3/n-6 ratio than captive A. leptodactylus, crayfish farms can potentially produce a better quality of crayfish meat by increasing the PUFA n-3 (especially DHA and EPA) in the diets of A. leptodactylus.

  14. Acidity characterization of heterogeneous catalysts by solid-state NMR spectroscopy using probe molecules.

    PubMed

    Zheng, Anmin; Liu, Shang-Bin; Deng, Feng

    2013-01-01

    Characterization of the surface acidic properties of solid acid catalysts is a key issue in heterogeneous catalysis. Important acid features of solid acids, such as their type (Brønsted vs. Lewis acid), distribution and accessibility (internal vs. external sites), concentration (amount), and strength of acid sites are crucial factors dictating their reactivity and selectivity. This short review provides information on different solid-state NMR techniques used for acidity characterization of solid acid catalysts. In particular, different approaches using probe molecules containing a specific nucleus of interest, such as pyridine-d5, 2-(13)C-acetone, trimethylphosphine, and trimethylphosphine oxide, are compared. Incorporation of valuable information (such as the adsorption structure, deprotonation energy, and NMR parameters) from density functional theory (DFT) calculations can yield explicit correlations between the chemical shift of adsorbed probe molecules and the intrinsic acid strength of solid acids. Methods that combine experimental NMR data with DFT calculations can therefore provide both qualitative and quantitative information on acid sites.

  15. Acid-base properties of water-soluble organic matter of forest soils, studied by the pK-spectroscopy method.

    PubMed

    Shamrikova, E V; Ryazanov, M A; Vanchikova, E V

    2006-11-01

    Using the potentiometric titration and pK spectroscopy method, acid-base properties of water-soluble organic matter of forest soils have been studied. Five acidic classes composed of different substances with pK(a) values around 3.6; 4.8; 6.7; 8.7 and 9.7 have been identified. Testing the properties of soluble soil fraction, it is to be taken into account that when it is isolated from non-soluble soil matter, some water-soluble substances remain in soil and do not pass into the solution. Most firmly adsorbed in soil are water-soluble components with pK(a) 9.6-9.8.

  16. Effect of Different Inclusion Level of Condensed Distillers Solubles Ratios and Oil Content on Amino Acid Digestibility of Corn Distillers Dried Grains with Solubles in Growing Pigs

    PubMed Central

    Li, P.; Xu, X.; Zhang, Q.; Liu, J. D.; Li, Q. Y.; Zhang, S.; Ma, X. K.; Piao, X. S.

    2015-01-01

    The purpose of this experiment was to determine and compare the digestibility of crude protein (CP) and amino acids (AA) in full-oil (no oil extracted) and de-oiled (oil extracted) corn distillers dried grains with solubles (DDGS) with different condensed distillers solubles (CDS) ratios. Six barrows (29.6±2.3 kg) fitted with ileal T-cannula were allotted into a 6×6 Latin square design. Each period was comprised of a 5-d adaption period followed by a 2-d collection of ileal digesta. The five test diets contained 62% DDGS as the sole source of AA. A nitrogen-free diet was used to measure the basal endogenous losses of CP and AA. Chromic oxide (0.3%) was used as an index in each diet. The results showed that CP and AA were very similar in 5 DDGS, but the standardized ileal digestibility (SID) of lysine (from 56.16% to 71.15%) and tryptophan (from 54.90% to 68.38%) had the lowest values and largest variation within the essential AA, which suggests reduced availability of AA and different levels of Maillard reactions in the five DDGS. The apparent ileal digestibility and SID of CP and most of AA in full-oil DDGS (sources 1 and 2) were greater (p<0.05) than de-oiled DDGS (sources 3, 4, and 5). Comparing the AA SID in the 5 DDGS, full-oil with low CDS ratio DDGS (source 1) had non-significantly higher values (p >0.05) than full-oil with high CDS ratio DDGS (source 2); however, the SID of most AA of de-oiled with low CDS ratios DDGS (source 3) were non-significantly lower (p>0.05) than de-oiled with high CDS ratio DDGS (source 4); and the de-oiled DDGS with middle CDS ratio (source 5) but with different drying processing had the lowest SID AA values. In conclusion, de-oiled DDGS had lower SID of CP and AA than full-oil DDGS; a higher CDS ratio tended to decrease the SID of AA in full-oil DDGS but not in de-oiled DDGS; and compared with CDS ratio, processing, especially drying, may have more of an effect on AA digestibility of DDGS. PMID:25557681

  17. Water-soluble dicarboxylic acids and ω-oxocarboxylic acids in size-segregated aerosols over northern Japan during spring: sources and formation processes

    NASA Astrophysics Data System (ADS)

    Deshmukh, Dhananjay Kumar; Kawamura, Kimitaka; Kobayashi, Minoru; Gowda, Divyavani

    2016-04-01

    Seven sets (AF01-AF07) of size-segregated aerosol (12-sizes) samples were collected using a Micro-Orifice Uniform Deposit Impactor (MOUDI) in Sapporo, Japan during the spring of 2001 to understand the sources and atmospheric processes of water-soluble organic aerosols in the outflow region of Asian dusts. The samples were analyzed for dicarboxylic acids (C2-C12) and ω-oxocarboxylic acids as well as inorganic ions. The molecular distribution of diacids showed the predominance of oxalic acid (C2) followed by malonic and succinic acids whereas ω-oxoacids showed the predominance of glyoxylic acid (ωC2) in size-segregated aerosols. SO42- and NH4+ are enriched in submicron mode whereas NO3- and Ca2+ are in supermicron mode. Most of diacids and ω-oxoacids are enriched in supermicron mode in the samples (AF01-AF03) influenced by the long-range transport of mineral dusts whereas enhanced presence in submicron mode was observed in other sample sets. The strong correlations of C2 with Ca2+ (r = 0.95-0.99) and NO3- (r = 0.96-0.98) in supermicron mode in the samples AF01-AF03 suggest the adsorption or production of C2 diacid via heterogeneous reaction on the surface of mineral dust during long-range atmospheric transport. The preferential enrichment of diacids and ω-oxoacids in mineral dust has important implications for the solubility and cloud nucleation properties of the dominant fraction of water-soluble organic aerosols. This study demonstrates that biofuel and biomass burning and mineral dust originated in East Asia are two major factors to control the size distribution of diacids and related compounds over northern Japan.

  18. Synthesis, characterization, solubility and stability studies of hydrate cocrystal of antitubercular Isoniazid with antioxidant and anti-bacterial Protocatechuic acid

    NASA Astrophysics Data System (ADS)

    Mashhadi, Syed Muddassir Ali; Yunus, Uzma; Bhatti, Moazzam Hussain; Ahmed, Imtiaz; Tahir, Muhammad Nawaz

    2016-08-01

    Isoniazid is an important component used in "triple therapy" to combat tuberculosis. It has reduced Tabletting formulations stability. Anti-oxidants are obligatory to counter oxidative stress, pulmonary inflammation, and free radical burst from macrophages caused in tuberculosis and other diseases. In the present study a hydrate cocrystal of Isoniazid with anti-oxidant and anti-inflammatory and anti-bacterial Protocatechuic acid (3,4-dihydroxybenzoic acid) in 1:1 is reported. This Cocrystal may have improved tabletting stability and anti-oxidant properties. Cocrystal structure analysis confirmed the existence of pyridine-carboxylic acid synthon in the Cocrystal. Other synthons of different graph sets involving Nsbnd H···O and Osbnd H···N bonds are formed between hydrazide group of isoniazid and coformer. Solubility studies revealed that cocrystal is less soluble as compared to isoniazid in buffer at pH 7.4 at 22 °C while stability studies at 80 °C for 24 h period disclosed the fact that cocrystal has higher stability than that of isoniazid.

  19. The Changes in Color, Soluble Sugars, Organic Acids, Anthocyanins and Aroma Components in "Starkrimson" during the Ripening Period in China.

    PubMed

    Liu, Yulian; Chen, Nianlai; Ma, Zonghuan; Che, Fei; Mao, Juan; Chen, Baihong

    2016-01-01

    "Starkrimson" is a traditional apple cultivar that was developed a long time ago and was widely cultivated in the arid region of the northern Wei River of China. However, little information regarding the quality characteristics of "Starkrimson" fruit has been reported in this area. To elucidate these characteristics, the color, soluble sugars, organic acids, anthocyanins and aroma components were measured during the ripening period through the use of high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). The results indicated that the changes in anthocyanin contents took place later than the changes in the Commission International Eclairage (CIE) parameters. Meanwhile, cyanidin 3-galactoside (cy3-gal), fructose, sucrose, glucose and malic acid were the primary organic compounds, and 1-butanol-2-methyl-acetate, 2-hexenal and 1-hexanol were the most abundant aroma components in the skin. Furthermore, rapidly changing soluble sugars and organic acid synchronization took place in the early ripening period, while rapidly changing aroma components occurred later, on the basis of fresh weight. This result suggested that the production of aroma components might be a useful index of apple maturity. PMID:27338331

  20. A comparison of water solubility enhancements of organic solutes by aquatic humic materials and commercial humic acids

    USGS Publications Warehouse

    Chlou, C.T.; Kile, D.E.; Brinton, T.I.; Malcolm, R.L.; Leenheer, J.A.; MacCarthy, P.

    1987-01-01

    Water solubility enhancements of 1,1-bis(p-chloro-phenyl)-2,2,2-trichloroethane (p,p???-DDT), 2,4,5,2???,5???-pentachlorobiphenyl (2,4,5,2???,5???-PCB), and 2,4,4???-tri-chlorobiphenyl (2,4,4???-PCB) by dissolved organic matter have been studied with the following samples: (1) acidic water samples from the Suwannee River, Georgia, and the Sopchoppy River, Florida; (2) a humic extract of a nearly neutral pH water from the Calcasieu River, Louisiana; (3) commercial humic acids from the Aldrich Chemical Co. and Fluka-Tridom Chemical Corp. The calculated partition coefficients on a dissolved organic carbon basis (Kdoc) for organic solutes with water samples and aquatic humic extracts from this and earlier studies indicate that the enhancement effect varies with the molecular composition of the aquatic humic materials. The Kdoc values with water and aquatic humic samples are, however, far less than the observed Kdoc values obtained with the two commercial samples, by factors of about 4-20. In view of this finding, one should be cautious in interpreting the effects of the dissolved organic matter on solubility enhancement of organic solutes on the basis of the use of commercial humic acids.

  1. Molecular weight distribution of soluble fiber fractions and short chain fatty acids in ileal digesta of growing pigs.

    PubMed

    Ivarsson, E; Andersson, R; Lindberg, J E

    2012-12-01

    The effect of dietary fiber source on molecular weight (MW) distribution of soluble fiber fractions and short chain fatty acids (SCFA) in ileal digesta of 7 post valve T-cecum (PVTC) cannulated growing pigs was studied. Pigs were fed semisynthetic diets with sugar beet (Beta vulgaris) pulp (SBP) or chicory (Cichorium intybus) forage (CFO) as fiber sources of which the soluble nonstarch polysaccharide (NSP) fraction originated mainly from pectin. Three MW intervals were selected-large MW (MWL): 10,000,000 to 1,000,000 g/mol, medium MW (MWM): 1,000,000 to 200,000 g/mol, and small MW (MWS): 200,000 to 10,000 g/mol-and the relative distribution (% of total) of molecules in each interval was calculated. The MWM fraction was higher (P < 0.05) in ileal digesta of pigs fed diet SBP and the MWS fraction was higher (P < 0.05) in ileal digesta of pigs fed diet CFO. The mole/100 mole of propionic acid (HPr) was higher (P < 0.010) in pigs fed diet SBP whereas pigs fed diet CFO had higher (P < 0.010) mole/100 mole of acetic acid (HAc). The proportion of the MWL and MWM fractions in ileal digesta were negatively correlated to HAc (r = -0.52, P = 0.05, and r = -0.62, P = 0.02, respectively). The proportion of MWM in ileal digesta was positively correlated to HPr (r = 0.83; P = 0.001) whereas MWS and HPr were negatively correlated (r = -0.76; P = 0.002). In conclusion, the bacterial degradation of the soluble NSP fraction is selective and MW distribution may explain differences in SCFA production.

  2. The determination of solubility and diffusion coefficient for solids in liquids by an inverse measurement technique using cylinders of amorphous glucose as a model compound

    NASA Astrophysics Data System (ADS)

    Hu, Chengyao; Huang, Pei

    2011-05-01

    The importance of sugar and sugar-containing materials is well recognized nowadays, owing to their application in industrial processes, particularly in the food, pharmaceutical and cosmetic industries. Because of the large numbers of those compounds involved and the relatively small number of solubility and/or diffusion coefficient data for each compound available, it is highly desirable to measure the solubility and/or diffusion coefficient as efficiently as possible and to be able to improve the accuracy of the methods used. In this work, a new technique was developed for the measurement of the diffusion coefficient of a stationary solid solute in a stagnant solvent which simultaneously measures solubility based on an inverse measurement problem algorithm with the real-time dissolved amount profile as a function of time. This study differs from established techniques in both the experimental method and the data analysis. The experimental method was developed in which the dissolved amount of solid solute in quiescent solvent was investigated using a continuous weighing technique. In the data analysis, the hybrid genetic algorithm is used to minimize an objective function containing a calculated and a measured dissolved amount with time. This is measured on a cylindrical sample of amorphous glucose in methanol or ethanol. The calculated dissolved amount, that is a function of the unknown physical properties of the solid solute in the solvent, is calculated by the solution of the two-dimensional nonlinear inverse natural convection problem. The estimated values of the solubility of amorphous glucose in methanol and ethanol at 293 K were respectively 32.1 g/100 g methanol and 1.48 g/100 g ethanol, in agreement with the literature values, and support the validity of the simultaneously measured diffusion coefficient. These results show the efficiency and the stability of the developed technique to simultaneously estimate the solubility and diffusion coefficient. Also

  3. Solubility and crystallographic facet tailoring of (GaN)(1-x)(ZnO)(x) pseudobinary solid-solution nanostructures as promising photocatalysts.

    PubMed

    Li, Jing; Liu, Baodan; Yang, Wenjin; Cho, Yujin; Zhang, Xinglai; Dierre, Benjamin; Sekiguchi, Takashi; Wu, Aimin; Jiang, Xin

    2016-02-14

    (GaN)1-x(ZnO)x solid-solution nanostructures with superior crystallinity, large surface areas and visible light absorption have been regarded as promising photocatalysts for overall water splitting to produce H2. In this work, we report the preparation of (GaN)1-x(ZnO)x solid-solution nanorods with a high ZnO solubility up to 95% via a two-step synthetic route, which starts from a sol-gel reaction and follows with a nitridation process. Moreover, we clearly demonstrated that the crystallographic facets of (GaN)1-x(ZnO)x solid-solution nanorods can be finely tailored from non-polar {10̄10} to semipolar {10̄11} and then finally to mixed {10̄1} and polar {000̄1} by carefully controlling the growth temperature and nitridation time. Correspondingly, the ZnO content in the GaN lattice can be achieved in the range of ∼25%-95%. Room-temperature cathodoluminescence (CL) measurements on the three types of (GaN)1-x(ZnO)x solid-solution nanorods indicate that the minimum band-gap of 2.46 eV of the solid-solution nanorods is achieved under a ZnO solubility of 25%. The efficiency and versatility of our strategy in the band-gap and facet engineering of (GaN)1-x(ZnO)x solid-solution nanorods will enhance their promising photocatalytic utilizations like an overall water splitting for H2 production under visible-light irradiation.

  4. Esterification of pseudoephedrine hydrochloride by citric acid in a solid dose pharmaceutical preparation.

    PubMed

    Goel, Alok; Zhao, Zhicheng; Sørensen, Dan; Zhou, Jay; Zhang, Fa

    2016-09-10

    Esterification of pseudoephedrine hydrochloride (PSE) by citric acid was observed in a solid dose pharmaceutical preparation at room temperature and accelerated stability condition (40°C/75% relative humidity). The esterification of PSE with citric acid was confirmed by a solid-state binary reaction in the presence of minor level of water at elevated temperature to generate three isomeric esters. The structures of the pseudoephedrine citric acid esters were elucidated using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy (NMR). Occurrence of esterification in solid state, instead of amidation which is generally more favorable than esterification, is likely due to remaining HCl salt form of solid pseudoephedrine hydrochloride to protect its amino group from amidation with citric acid. In contrast, the esterification was not observed from solution reaction between PSE and citric acid.

  5. Esterification of pseudoephedrine hydrochloride by citric acid in a solid dose pharmaceutical preparation.

    PubMed

    Goel, Alok; Zhao, Zhicheng; Sørensen, Dan; Zhou, Jay; Zhang, Fa

    2016-09-10

    Esterification of pseudoephedrine hydrochloride (PSE) by citric acid was observed in a solid dose pharmaceutical preparation at room temperature and accelerated stability condition (40°C/75% relative humidity). The esterification of PSE with citric acid was confirmed by a solid-state binary reaction in the presence of minor level of water at elevated temperature to generate three isomeric esters. The structures of the pseudoephedrine citric acid esters were elucidated using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy (NMR). Occurrence of esterification in solid state, instead of amidation which is generally more favorable than esterification, is likely due to remaining HCl salt form of solid pseudoephedrine hydrochloride to protect its amino group from amidation with citric acid. In contrast, the esterification was not observed from solution reaction between PSE and citric acid. PMID:27474946

  6. Intermediates to ethylene glycol: carbonylation of formaldehyde catalyzed by Nafion solid perfluorosulfonic acid resin

    SciTech Connect

    Hendriksen, D.E.

    1983-01-01

    Details of a series of reactions for the production of ethylene glycol using a catalyst of Nafion solid perfluorosulfonic acid resin was detailed. The reactions included the carbonylation of formaldehyde and esterification and then hydrogenation of the product of the carbonylation, glycolic acid. Other preparations included in the work included methyl glycolate, acetylglycolic acid, methyl acetylglycolate, and methyl methoxyacetate.

  7. Preparation and characterisation of Kolliphor® P 188 and P 237 solid dispersion oral tablets containing the poorly water soluble drug disulfiram.

    PubMed

    Ramadhani, Nisrina; Shabir, Mehwish; McConville, Christopher

    2014-11-20

    The oral route of administration is the most common and preferred route of drug delivery due to its ease of administration, cost-effectiveness and flexibility in design. However, limited aqueous solubility of the active pharmaceutical ingredient can result in poor bioavailability, which is a major issue for the pharmaceutical industry. Increasing numbers of new drugs are falling into class II of the Biopharmaceutical Classification System (BCS), where they have a low solubility and high tissue permeability, meaning that bioavailability is solubility dependent. Here we demonstrate the development and characterisation of solid dispersion oral tablets, containing the poorly water-soluble drug disulfiram, prepared using both the hot melt and solvent evaporation methods and manufactured from two different polymers, Kolliphor(®) P 188 and P 237, specifically designed for the manufacture of solid dispersions. This paper demonstrates that the disulfiram solid dispersions tablets have an enhanced release rate of disulfiram compared to the control tablets. The Kolliphor(®) P 188 polymer control tablets released approximately 48.8% of their disulfiram content over 8h, with the solvent evaporated tablets releasing approximately 65.8%, while the 60 and 80 °C hot melt tablets released approximately 73.2 and 100% of their disulfiram content respectively. A similar trend was seen with Kolliphor(®) P 237 as the control tablets released approximately 50.5% of their disulfiram content over 8h, while the solvent evaporated tablets released approximately 79.5% and the 60 and 80 °C hot melt tablets released 100.2 and 100.3% respectively. Depending on what method and polymer is used to manufacture the solid dispersions the disulfiram is either maintained completely or partially in its amorphous state and it is this which enhances its solubility and release rate from the tablets. The disulfiram in the Kolliphor(®) P 188 solvent evaporated and 60 °C hot melt tablets retained 50

  8. Solid solubility of rare earth elements (Nd, Eu, Tb) in In2-xSnxO3 - effect on electrical conductivity and optical properties.

    PubMed

    Sunde, T O L; Lindgren, M; Mason, T O; Einarsrud, M-A; Grande, T

    2014-07-01

    Wide band-gap semiconductors doped with luminescent rare earth elements (REEs) have attracted recent interest due to their unique optical properties. Here we report on the synthesis of the transparent conducting oxides (TCOs) indium oxide and indium tin oxide (ITO) doped with neodymium, europium and terbium. The solid solubility in the systems was investigated and isothermal phase diagrams at 1400 °C were proposed. The solubility of the REEs in In2O3 is mainly determined by the size of the rare earth dopant, while in ITO the solid solubility was reduced due to a strong tendency of the tin and REE co-dopants to form a pyrochlore phase. The effect of the REE-doping on the conductivity of the host was determined and optical activity of the REE dopants were investigated in selected host materials. The conductivity of sintered materials of REE-doped In2O3 was significantly reduced, even at small doping concentrations, due to a decrease in carrier mobility. The same decrease in mobility was not observed in thin films of the material processed at lower temperatures. Strong emissions at around 611 nm were observed for Eu-doped In2O3, demonstrating the possibility of obtaining photoluminescence in a TCO host, while no emissions was observed for Nd- and Tb-doping. PMID:24832103

  9. Unexpected solvent impact in the crystallinity of praziquantel/poly(vinylpyrrolidone) formulations. A solubility, DSC and solid-state NMR study.

    PubMed

    Costa, Emanuel D; Priotti, Josefina; Orlandi, Silvina; Leonardi, Darío; Lamas, María C; Nunes, Teresa G; Diogo, Hermínio P; Salomon, Claudio J; Ferreira, M João

    2016-09-25

    The saturation solubility of PVP:PZQ physical mixtures (PMs) and solid dispersions (SDs) prepared from ethanol (E/E) or ethanol/water (E/W) by the solvent evaporation method at 1:1, 2:1 and 3:1 ratio (w/w) was determined. The presence of PVP improves the solubility of PZQ (0.31±0.01mg/mL). A maximum of 1.29±0.03mg/mL of PZQ in solution was achieved for the 3:1 SD (E/E). The amount of PZQ in solution depends on the amount of polymer and on the preparation method. Solid-state NMR (ssNMR) and DSC were used to understand this behavior. Results show that PMs are a mixture of crystalline PZQ with the polymer, while SDs show different degrees of drug amorphization depending on the solvent used. For E/W SDs, PZQ exists in amorphous and crystalline states, with no clear correlation between the amount of crystalline PZQ and the amount of PVP. For E/E SDs, formulations with a higher percentage of PZQ are amorphous with the components miscible in domains larger than 3nm ((1)H ssNMR relaxation measurements). Albeit its higher saturation solubility, the 3:1 E/E PVP:PZQ sample has a significant crystalline content, probably due to the water introduced by the polymer. High PVP content and small crystal size account for this result.

  10. Synthesis of silver nanocubes with controlled size using water-soluble poly(amic acid) salt as the intermediate via a novel ion-exchange self-assembly technique.

    PubMed

    Qi, Shengli; Shen, Xiangyue; Lin, Zhiwei; Tian, GuoFeng; Wu, Dezhen; Jin, Riguang

    2013-12-21

    Here, we report for the first time on the successful fabrication of monodispersed silver nanocubes with regular shape and controlled size in the solid phase via a novel ion-exchange self-assembly technique by using water-soluble poly(amic acid) salt as the intermediate and silver nitrate as the metal precursor. By simply altering the annealing times at high temperature, the size of the silver nanocubes could be finely tuned in the range of 90-160 nm in the present case. Further attempts with different metal salts show that the present method is also feasible for other metal species and might be universal.

  11. Acid-base components of solid surfaces and the triboelectric series

    NASA Astrophysics Data System (ADS)

    Clint, J. H.; Dunstan, T. S.

    2001-05-01

    Contact electrification between solids is often explained qualitatively in terms of the relative positions of the materials in the triboelectric series. It is shown that the series can be put on a quantitative basis by analysing data for the wetting, by suitable probe liquids, of individual solid surfaces. In one approach to solid surface energies the polar fraction can be split into contributions from Lewis acid (electron-acceptor) and base (electron-donor) components. Using data for solid surface energy components in the literature it is shown that there is a good correlation between the electron-donor surface tension parameter and the position of the solid in the triboelectric series.

  12. Comparison between liquid and solid acids catalysts on reducing sugars conversion from furfural residues via pretreatments.

    PubMed

    Lin, Keying; Ma, Baojun; Sun, Yuan; Liu, Wanyi

    2014-09-01

    Liquid sulphuric acid is adopted and compared with carbon-based sulfonated solid acids (coal tar-based and active carbon-based) for furfural residues conversion into reducing sugars. The optimum hydrolysis conditions of liquid acid are at 4% of sulphuric acid, 25:1 of liquid and solid ratio, 175°C of reaction temperature and 120 min of reaction time. The reducing sugar yields are reached over 60% on liquid acid via NaOH/H2O2, NaOH/microwave and NaOH/ultrasonic pretreatments, whereas only over 30% on solid acids. The TOFs (turnover number frequency) via NaOH/H2O2 pretreatments are 0.093, 0.020 and 0.023 h(-1) for liquid sulphuric acid, coal tar-based and active carbon-based solid acids catalysts, respectively. Considering the efficiency, cost and environment factors, the liquid and solid acids have their own advantages of potential commercial application values.

  13. Synthesis of silver nanocubes with controlled size using water-soluble poly(amic acid) salt as the intermediate via a novel ion-exchange self-assembly technique

    NASA Astrophysics Data System (ADS)

    Qi, Shengli; Shen, Xiangyue; Lin, Zhiwei; Tian, Guofeng; Wu, Dezhen; Jin, Riguang

    2013-11-01

    Here, we report for the first time on the successful fabrication of monodispersed silver nanocubes with regular shape and controlled size in the solid phase via a novel ion-exchange self-assembly technique by using water-soluble poly(amic acid) salt as the intermediate and silver nitrate as the metal precursor. By simply altering the annealing times at high temperature, the size of the silver nanocubes could be finely tuned in the range of 90-160 nm in the present case. Further attempts with different metal salts show that the present method is also feasible for other metal species and might be universal.Here, we report for the first time on the successful fabrication of monodispersed silver nanocubes with regular shape and controlled size in the solid phase via a novel ion-exchange self-assembly technique by using water-soluble poly(amic acid) salt as the intermediate and silver nitrate as the metal precursor. By simply altering the annealing times at high temperature, the size of the silver nanocubes could be finely tuned in the range of 90-160 nm in the present case. Further attempts with different metal salts show that the present method is also feasible for other metal species and might be universal. Electronic supplementary information (ESI) available: SEM images for the CuO, NiO and Co3O4 nanocubes prepared by the ion-exchange self-assembly technique by using CuCl2, NiSO4 and Co(NO3)2 as the metal precursors and PMDA/ODA-based water-soluble poly(amic acid) salt as the intermediate (Fig. S1-S3) TGA, DSC and DMTA analyses for the pure poly(amic acid) salt and that loaded with 1 mol% silver(i) (Fig. S4-S6). See DOI: 10.1039/c3nr03212d

  14. Monitoring acidic and basic molecular contamination in leading edge lithography and metrology applications: quantitative comparison of solid state and impinger-based sampling methods

    NASA Astrophysics Data System (ADS)

    Riddle Vogt, Sarah; Landoni, Cristian

    2010-03-01

    Assessing molecular contamination (MC) at part-per-billion (ppbV) or part-per-trillion volume (pptV) levels in cleanroom air and purge gas lines is essential to protect lithography and metrology tools optics and components. Current lithography and metrology tool manufacturer's specifications require testing of some contaminants down to single digit pptV levels. Ideally this analysis would be performed with an on-line analyzer (capable of providing almost instant results): the best analyzers currently available are only capable of providing 100 pptV detection. Liquid impinger sampling has been the dominant sample collection method for sub ppbV acidic and basic MC analysis. Impinger sampling suffers from some inherent problems that can dramatically reduce the collection efficiency such as analyte solubility and evaporative losses. An innovative solid-state trapping technology has been recently developed by SAES Pure Gas along with the CollectTorr sampling system. NIST traceable gas phase standards have been used to compare the collection efficiency of the traditional impinger technology to that of the solid state trapping method. Results varied greatly for the different acid gases with sulfur dioxide showing comparable collection efficiencies while hydrofluoric acid and hydrochloric acid showed much lower recoveries in the impingers than the solid-state traps. Ammonia collection efficiencies were slightly higher for the solid state traps and were improved in the impingers when an acidified solution was used as the collection media. The use of solid-state traps, besides being much simpler from both the handling and logistical stand point, eliminates the analyte solubility and evaporation problems frequently seen with the impinger sampling.

  15. Micro-scale prediction method for API-solubility in polymeric matrices and process model for forming amorphous solid dispersion by hot-melt extrusion.

    PubMed

    Bochmann, Esther S; Neumann, Dirk; Gryczke, Andreas; Wagner, Karl G

    2016-10-01

    A new predictive micro-scale solubility and process model for amorphous solid dispersions (ASDs) by hot-melt extrusion (HME) is presented. It is based on DSC measurements consisting of an annealing step and a subsequent analysis of the glass transition temperature (Tg). The application of a complex mathematical model (BCKV-equation) to describe the dependency of Tg on the active pharmaceutical ingredient (API)/polymer ratio, enables the prediction of API solubility at ambient conditions (25°C). Furthermore, estimation of the minimal processing temperature for forming ASDs during HME trials could be defined and was additionally confirmed by X-ray powder diffraction data. The suitability of the DSC method was confirmed with melt rheological trials (small amplitude oscillatory system). As an example, ball milled physical mixtures of dipyridamole, indomethacin, itraconazole and nifedipine in poly(vinylpyrrolidone-co-vinylacetate) (copovidone) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®) were used.

  16. Application of melt extrusion in the development of a physically and chemically stable high-energy amorphous solid dispersion of a poorly water-soluble drug.

    PubMed

    Lakshman, Jay P; Cao, Yu; Kowalski, James; Serajuddin, Abu T M

    2008-01-01

    Formulation of active pharmaceutical ingredients (API) in high-energy amorphous forms is a common strategy to enhance solubility, dissolution rate and, consequently, oral bioavailability of poorly water-soluble drugs. Amorphous APIs are, however, susceptible to recrystallization and, therefore, there is a need to physically stabilize them as solid dispersions in polymeric carriers. Hot melt extrusion has in recent years gained wide acceptance as a method of choice for the preparation of solid dispersions. There is a potential that the API, the polymer or both may degrade if excessively high temperature is needed in the melt extrusion process, especially when the melting point of the API is high. This report details a novel method where the API was first converted to an amorphous form by solvent evaporation and then melt-extruded with a suitable polymer at a drug load of at least 20% w/w. By this means, melt extrusion could be performed much below the melting temperature of the drug substance. Since the glass transition temperature of the amorphous drug was lower than that of the polymer used, the drug substance itself served as the plasticizer for the polymer. The addition of surfactants in the matrix enhanced dispersion and subsequent dissolution of the drug in aqueous media. The amorphous melt extrusion formulations showed higher bioavailability than formulations containing the crystalline API. There was no conversion of amorphous solid to its crystalline form during accelerated stability testing of dosage forms.

  17. Replacement of liquid H{sub 2}SO{sub 4} and HF with solid acid catalysts: A study of mixed metal phosphates as solid acid catalysts

    SciTech Connect

    Jackson, N.B.; Nenoff, T.M.; Thoma, S.G.; Kohler, S.D.

    1997-10-01

    The primary purpose of this LDRD was to identify and optimize materials as solid acid catalysts for the replacement of environmentally hazardous liquid acids such as H{sub 2}SO{sub 4} and HF which are used as catalysts in both the petroleum and chemical industries. Liquid acids have significant safety, environmental and engineering difficulties associated with their use in process chemistry. Special equipment/materials need to be used with liquid acids. Hydrofluoric acid poses unique safety problems due to it insipid attack on skin and tissue as well as its tendency to plume and travel long distances as a plume when it is released in the atmosphere. Therefore, any time a solid acid catalyst can be used to replace a liquid acid in a processes step, significant environmental, safety, and financial gains can be realized. The majority of work in this LDRD was performed on novel mixed metal phosphates which are a new solid acid catalyst material. Primarily the model reaction, 2-methyl-2-pentene isomerization, was used to determine acidity. These materials were tested for their activity, their deactivation and their stability. In addition, some of the phosphate materials were synthesized using templates in order to try to form a three dimensional network material from these phosphates. The amorphous sulfated zirconium-titanium phosphates were more acidic, as measured by olefin isomerization, than sulfated zirconia. However, they showed some of the same failings as sulfated zirconia in that they deactivated quickly and lost sulfur in a reducing atmosphere. Certain of the mixed metal phosphates, particularly tantalum-containing phosphates, showed strong acidity compared to sulfated zirconia as measured by olefin isomerization reaction.

  18. Defensive strategies in Geranium sylvaticum. Part 1: organ-specific distribution of water-soluble tannins, flavonoids and phenolic acids.

    PubMed

    Tuominen, Anu; Toivonen, Eija; Mutikainen, Pia; Salminen, Juha-Pekka

    2013-11-01

    A combination of high-resolution mass spectrometry and modern HPLC column technology, assisted by diode array detection, was used for accurate characterization of water-soluble polyphenolic compounds in the pistils, stamens, petals, sepals, stems, leaves, roots and seeds of Geranium sylvaticum. The organs contained a large variety of polyphenols, five types of tannins (ellagitannins, proanthocyanidins, gallotannins, galloyl glucoses and galloyl quinic acids) as well as flavonoids and simple phenolic acids. In all, 59 compounds were identified. Geraniin and other ellagitannins dominated in all the green photosynthetic organs. The other organs seem to produce distinctive polyphenol groups: pistils accumulated gallotannins; petals acetylglucose derivatives of galloylglucoses; stamens kaempferol glycosides, and seeds and roots accumulated proanthocyanidins. The intra-plant distribution of the different polyphenol groups may reflect the different functions and importance of various types of tannins as the defensive chemicals against herbivory.

  19. Protection from hypertension in mice by the Mediterranean diet is mediated by nitro fatty acid inhibition of soluble epoxide hydrolase

    PubMed Central

    Charles, Rebecca L.; Rudyk, Olena; Prysyazhna, Oleksandra; Kamynina, Alisa; Yang, Jun; Morisseau, Christophe; Hammock, Bruce D.; Freeman, Bruce A.; Eaton, Philip

    2014-01-01

    Soluble epoxide hydrolase (sEH) is inhibited by electrophilic lipids by their adduction to Cys521 proximal to its catalytic center. This inhibition prevents hydrolysis of the enzymes’ epoxyeicosatrienoic acid (EET) substrates, so they accumulate inducing vasodilation to lower blood pressure (BP). We generated a Cys521Ser sEH redox-dead knockin (KI) mouse model that was resistant to this mode of inhibition. The electrophilic lipid 10-nitro-oleic acid (NO2-OA) inhibited hydrolase activity and also lowered BP in an angiotensin II-induced hypertension model in wild-type (WT) but not KI mice. Furthermore, EET/dihydroxy-epoxyeicosatrienoic acid isomer ratios were elevated in plasma from WT but not KI mice following NO2-OA treatment, consistent with the redox-dead mutant being resistant to inhibition by lipid electrophiles. sEH was inhibited in WT mice fed linoleic acid and nitrite, key constituents of the Mediterranean diet that elevates electrophilic nitro fatty acid levels, whereas KIs were unaffected. These observations reveal that lipid electrophiles such as NO2-OA mediate antihypertensive signaling actions by inhibiting sEH and suggest a mechanism accounting for protection from hypertension afforded by the Mediterranean diet. PMID:24843165

  20. In vitro oxidation of indoleacetic acid by soluble auxin-oxidases and peroxidases from maize roots. [Zea mays L

    SciTech Connect

    Beffa, R.; Martin, H.V.; Pilet, P.E. )

    1990-10-01

    Soluble auxin-oxidases were extracted from Zea mays L. cv LG11 apical root segments and partially separated from peroxidases (EC 1.11.1.7) by size-exclusion chromatography. Auxin-oxidases were resolved into one main peak corresponding to a molecular mass of 32.5 kilodaltons and a minor peak at 54.5 kilodaltons. Peroxidases were separated into at least four peaks, with molecular masses from 32.5 to 78 kilodaltons. In vitro activity of indoleacetic acid-oxidases was dependent on the presence of MnCl{sub 2} and p-coumaric acid. Compound(s) present in the crude extract and several synthetic auxin transport inhibitors (including 2,3,5-triiodobenzoic acid and N-1-naphthylphthalamic acid) inhibited auxin-oxidase activity, but had no effect on peroxidases. The products resulting from the in vitro enzymatic oxidation of ({sup 3}H)indoleacetic acid were separated by HPLC and the major metabolite was found to cochromatograph with indol-3yl-methanol.

  1. Microencapsulation of linoleic acid with low- and high-molecular-weight components of soluble soybean polysaccharide and its oxidation process.

    PubMed

    Fang, Xu; Watanabe, Yoshiyuki; Adachi, Shuji; Matsumura, Yasuki; Mori, Tomohiko; Maeda, Hirokazu; Nakamura, Akihiro; Matsuno, Ryuichi

    2003-09-01

    Soluble soybean polysaccharide (SSPS) was fractionated into its low- (LMW) and high-molecular-weight (HMW) components to test their antioxidative and emulsifying properties. Linoleic acid was emulsified with an aqueous solution of SSPS, HMW, a mixture of LMW or HMW with maltodextrin, or maltodextrin alone. The emulsions prepared with SSPS, HWM and the mixture of HMW with maltodextrin were stable. These emulsions were spay-dried to produce microcapsules. The encapsulated linoleic acid was oxidized at 37 degrees C and at various levels of relative humidity. Linoleic acid encapsulated with the mixture of LMW with maltodextrin or HMW was stable to oxidation, and this stability increased as the weight fraction of LMW in the mixture was increased. The LMW components also had high DPPH-radical scavenging activity. These results indicate that LMW played an important role in suppressing or retarding the oxidation of linoleic acid encapsulated with SSPS. The oxidative stability of linoleic acid encapsulated with a mixture of the LMW and HMW components was high at low and high relative humidity, but not at intermediate levels of relative humidity.

  2. Interaction of water-soluble amino acid Schiff base complexes with bovine serum albumin: Fluorescence and circular dichroism studies

    NASA Astrophysics Data System (ADS)

    Gharagozlou, Mehrnaz; Boghaei, Davar M.

    2008-12-01

    Fluorescence spectroscopy in combination with circular dichroism (CD) spectroscopy were used to investigate the interaction of water-soluble amino acid Schiff base complexes, [Zn(L 1,2)(phen)] where phen is 1,10-phenanthroline and H 2L 1,2 is amino acid Schiff base ligands, with bovine serum albumin (BSA) under the physiological conditions in phosphate buffer solution adjusted to pH 7.0. The quenching mechanism of fluorescence was suggested as static quenching according to the Stern-Volmer equation. Quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between amino acid Schiff base complexes and BSA. The thermodynamic parameters Δ G, Δ H and Δ S at different temperatures (298, 310 and 318 K) were calculated. The results indicate that the hydrophobic and hydrogen bonding interactions play a major role in [Zn(L 1)(phen)]-BSA association, whereas hydrophobic and electrostatic interactions participate a main role in [Zn(L 2)(phen)]-BSA binding process. Binding studies concerning the number of binding sites and apparent binding constant Kb were performed by fluorescence quenching method. The distance R between the donor (BSA) and acceptor (amino acid Schiff base complexes) has been obtained utilizing fluorescence resonant energy transfer (FRET). Furthermore, CD spectra were used to investigate the structural changes of the BSA molecule with the addition of amino acid Schiff base complexes. The results indicate that the interaction of amino acid Schiff base complexes with BSA leads to changes in the secondary structure of the protein. Fractional contents of the secondary structure of BSA ( fα, fβ, fturn and frandom) were calculated with and without amino acid Schiff base complexes utilizing circular dichroism spectroscopy. Our results clarified that amino acid Schiff base complexes could bind to BSA and be effectively transported and eliminated in the body, which could be a useful guideline for further drug

  3. Utilization of Condensed Distillers Solubles as Nutrient Supplement for Production of Nisin and Lactic Acid from Whey

    NASA Astrophysics Data System (ADS)

    Liu, Chuanbin; Hu, Bo; Chen, Shulin; Glass, Richard W.

    The major challenge associated with the rapid growth of the ethanol industry is the usage of the coproducts, i.e., condensed distillers solubles (CDS) and distillers dried grains, which are currently sold as animal feed supplements. As the growth of the livestock industries remains flat, alternative usage of these coproducts is urgently needed. CDS is obtained after the removal of ethanol by distillation from the yeast fermentation of a grain or a grain mixture by condensing the thin stillage fraction to semisolid. In this work, CDS was first characterized and yeast biomass was proven to be the major component of CDS. CDS contained 7.50% crude protein but with only 42% of that protein being water soluble. Then, CDS was applied as a nutrient supplement for simultaneous production of nisin and lactic acid by Lactococcus lactis subsp. lactis (ATCC 11454). Although CDS was able to support bacteria growth and nisin production, a strong inhibition was observed when CDS was overdosed. This may be caused by the existence of the major ethanol fermentation byproducts, especially lactate and acetate, in CDS. In the final step, the CDS based medium composition for nisin and lactic acid production was optimized using response surface methodology.

  4. Influence of certain essential oils on carcinogen-metabolizing enzymes and acid-soluble sulfhydryls in mouse liver.

    PubMed

    Banerjee, S; Sharma, R; Kale, R K; Rao, A R

    1994-01-01

    The influence of essential oils from naturally occurring plant dietary items such as cardamom, celery seed, cumin seed, coriander, ginger, nutmeg, and zanthoxylum on the activities of hepatic carcinogen-metabolizing enzymes (cytochrome P450, aryl hydrocarbon hydroxylase, and glutathione S-transferase) and acid-soluble sulfhydryl level was investigated in Swiss albino mice. Each oil was fed by gavage at 10 microliters/day for 14 days, and then the animals were sacrificed and their hepatic enzyme activities and sulfhydryl levels were evaluated. Only nutmeg and zanthoxylum oils induced cytochrome P450 level significantly (p < 0.05), whereas cardamom oil caused a significant reduction in its activity (p < 0.05). Furthermore, aryl hydrocarbon hydroxylase activity was significantly elevated only by treatment with ginger oil (p < 0.01), whereas nutmeg oil caused a significant reduction in its activity (p < 0.01). The remaining oils did not significantly alter the level of cytochrome P450 and aryl hydrocarbon hydroxylase activity. Glutathione S-transferase activity was significantly elevated in all experimental groups (p < 0.1-p < 0.001) compared with controls. The acid-soluble sulfhydryl was significantly elevated only by the essential oils of cardamom (p < 0.05), nutmeg (p < 0.05), and zanthoxylum (p < 0.01). Our observations suggest that intake of essential oils affects the host enzymes associated with activation and detoxication of xenobiotic compounds, including chemical carcinogens and mutagens. PMID:8072879

  5. Rational design of translational pausing without altering the amino acid sequence dramatically promotes soluble protein expression: a strategic demonstration.

    PubMed

    Chen, Wei; Jin, Jingjie; Gu, Wei; Wei, Bo; Lei, Yun; Xiong, Sheng; Zhang, Gong

    2014-11-10

    The production of many pharmaceutical and industrial proteins in prokaryotic hosts is hindered by the insolubility of industrial expression products resulting from misfolding. Even with a correct primary sequence, an improper translation elongation rate in a heterologous expression system is an important cause of misfolding. In silico analysis revealed that most of the endogenous Escherichia coli genes display translational pausing sites that promote correct folding, and almost 1/5 genes have pausing sites at the 3'-termini of their coding sequence. Therefore, we established a novel strategy to efficiently promote the expression of soluble and active proteins without altering the amino acid sequence or expression conditions. This strategy uses the rational design of translational pausing based on structural information solely through synonymous substitutions, i.e. no change on the amino acids sequence. We demonstrated this strategy on a promising antiviral candidate, Cyanovirin-N (CVN), which could not be efficiently expressed in any previously reported system. By introducing silent mutations, we increased the soluble expression level in E. coli by 2000-fold without altering the CVN protein sequence, and the specific activity was slightly higher for the optimized CVN than for the wild-type variant. This strategy introduces new possibilities for the production of bioactive recombinant proteins.

  6. Encapsulation of ployunsaturated fatty acid esters with solid lipid particles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyunsaturated fatty acids (PUFA) such as a-linolenic acid (ALA) and docosahexaenoic acid (DHA) are known to improve cardiovascular and nervous system health. These compounds are increasingly used in food and animal feed formulations. However, the high degree of unsaturation in these structures can...

  7. High abundances of water-soluble dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the mountaintop aerosols over the North China Plain during wheat burning season

    NASA Astrophysics Data System (ADS)

    Kawamura, K.; Tachibana, E.; Okuzawa, K.; Aggarwal, S. G.; Kanaya, Y.; Wang, Z. F.

    2013-08-01

    Aerosol (TSP) samples were collected at the summit of Mount Tai (elevation: 1534 m a.s.l., 36.25° N, 117.10° E) located in the North China Plain using a high-volume air sampler and pre-combusted quartz filters. Sampling was conducted on day/night or 3 h basis in the period from 29 May to 28 June 2006 during the field burning of wheat straw residue and the post-burning season. The filter samples were analyzed for low-molecular-weight dicarboxylic acids, ketoacids and α-dicarbonyls using capillary gas chromatography (GC) and GC-MS employing water extraction and butyl ester derivatization. Molecular distributions of dicarboxylic acids (C2-C11, 220-6070 ng m-3) were characterized by a predominance of oxalic (C2) acid (105-3920 ng m-3) followed by succinic (C4) or malonic (C3) acid. Unsaturated aliphatic diacids, including maleic (M), isomaleic (iM) and fumaric (F) acids, were also detected together with aromatic diacids (phthalic, isophthalic and terephthalic acids). ω-oxocarboxylic acids (C2-C9, 24-610 ng m-3) were detected as the second most abundant compound class with the predominance of glyoxylic acid (11-360 ng m-3), followed by α-ketoacid (pyruvic acid, 3-140 ng m-3) and α-dicarbonyls (glyoxal, 1-230 ng m-3 and methylglyoxal, 2-120 ng m-3). We found that these levels (>6000 ng m-3 for diacids) are several times higher than those reported in Chinese megacities at ground levels. The concentrations of diacids increased from late May to early June, showing a maximum on 7 June, and then significantly decreased during the period 8-11 June, when the wind direction shifted from southerly to northerly. Similar temporal trends were found for ketocarboxylic acids and α-dicarbonyls as well as total carbon (TC) and water-soluble organic carbon (WSOC). The temporal variations of water-soluble organics were interpreted by the direct emission from the field burning of agricultural wastes (wheat straw) in the North China Plain and the subsequent photochemical oxidation of

  8. A Mini-Review on Solid Acid Catalysts for Esterification Reactions

    NASA Astrophysics Data System (ADS)

    Sirsam, Rajkumar; Hansora, Dharmesh; Usmani, Ghayas A.

    2016-04-01

    This paper presents an overview of research pertaining to solid acid catalysts for esterification reactions. Prominence has been given to the literatures that have been appeared during the last two decades. A variety of reactions catalyzed by solid acid catalysts have been tabulated according to their broad classification; industrially important reactions have been outlined. Examples, where the use of various solid acid catalysts have led to an improvement in the selectivity of the desired products, have also been discussed. Various catalyzed esterification reactions using different approaches and previous kinetic studies have been reviewed. Types, preparation and synthesis of various solid acid catalysts have been reviewed and discussed. Suggestions have been summarized for their implementation in future work.

  9. The effect of low solubility organic acids on the hygroscopicity of sodium halide aerosols

    NASA Astrophysics Data System (ADS)

    Miñambres, L.; Méndez, E.; Sánchez, M. N.; Castaño, F.; Basterretxea, F. J.

    2014-10-01

    In order to accurately assess the influence of fatty acids on the hygroscopic and other physicochemical properties of sea salt aerosols, hexanoic, octanoic or lauric acid together with sodium halide salts (NaCl, NaBr and NaI) have been chosen to be investigated in this study. The hygroscopic properties of sodium halide sub-micrometre particles covered with organic acids have been examined by Fourier-transform infrared spectroscopy in an aerosol flow cell. Covered particles were generated by flowing atomized sodium halide particles (either dry or aqueous) through a heated oven containing the gaseous acid. The obtained results indicate that gaseous organic acids easily nucleate onto dry and aqueous sodium halide particles. On the other hand, scanning electron microscopy (SEM) images indicate that lauric acid coating on NaCl particles makes them to aggregate in small clusters. The hygroscopic behaviour of covered sodium halide particles in deliquescence mode shows different features with the exchange of the halide ion, whereas the organic surfactant has little effect in NaBr particles, NaCl and NaI covered particles experience appreciable shifts in their deliquescence relative humidities, with different trends observed for each of the acids studied. In efflorescence mode, the overall effect of the organic covering is to retard the loss of water in the particles. It has been observed that the presence of gaseous water in heterogeneously nucleated particles tends to displace the cover of hexanoic acid to energetically stabilize the system.

  10. Characterization of a soluble phosphatidic acid phosphatase in bitter melon (Momordica charantia)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initia...

  11. Influence of cold stress on contents of soluble sugars, vitamin C and free amino acids including gamma-aminobutyric acid (GABA) in spinach (Spinacia oleracea).

    PubMed

    Yoon, Young-Eun; Kuppusamy, Saranya; Cho, Kye Man; Kim, Pil Joo; Kwack, Yong-Bum; Lee, Yong Bok

    2017-01-15

    The contents of soluble sugars (sucrose, fructose, glucose, maltose and raffinose), vitamin C and free amino acids (34 compounds, essential and non-essential) were quantified in open-field and greenhouse-grown spinaches in response to cold stress using liquid chromatography. In general, greenhouse cultivation produced nutritionally high value spinach in a shorter growing period, where the soluble sugars, vitamin C and total amino acids concentrations, including essential were in larger amounts compared to those grown in open-field scenarios. Further, low temperature exposure of spinach during a shorter growth period resulted in the production of spinach with high sucrose, ascorbate, proline, gamma-aminobutyric acid, valine and leucine content, and these constitute the most important energy/nutrient sources. In conclusion, cultivation of spinach in greenhouse at a low temperature (4-7°C) and exposure for a shorter period (7-21days) before harvest is recommended. This strategy will produce a high quality product that people can eat. PMID:27542466

  12. Influence of cold stress on contents of soluble sugars, vitamin C and free amino acids including gamma-aminobutyric acid (GABA) in spinach (Spinacia oleracea).

    PubMed

    Yoon, Young-Eun; Kuppusamy, Saranya; Cho, Kye Man; Kim, Pil Joo; Kwack, Yong-Bum; Lee, Yong Bok

    2017-01-15

    The contents of soluble sugars (sucrose, fructose, glucose, maltose and raffinose), vitamin C and free amino acids (34 compounds, essential and non-essential) were quantified in open-field and greenhouse-grown spinaches in response to cold stress using liquid chromatography. In general, greenhouse cultivation produced nutritionally high value spinach in a shorter growing period, where the soluble sugars, vitamin C and total amino acids concentrations, including essential were in larger amounts compared to those grown in open-field scenarios. Further, low temperature exposure of spinach during a shorter growth period resulted in the production of spinach with high sucrose, ascorbate, proline, gamma-aminobutyric acid, valine and leucine content, and these constitute the most important energy/nutrient sources. In conclusion, cultivation of spinach in greenhouse at a low temperature (4-7°C) and exposure for a shorter period (7-21days) before harvest is recommended. This strategy will produce a high quality product that people can eat.

  13. Solid solubility, phase transitions, thermal expansion, and compressibility in Sc{sub 1−x}Al{sub x}F{sub 3}

    SciTech Connect

    Morelock, Cody R.; Gallington, Leighanne C.; Wilkinson, Angus P.

    2015-02-15

    With the goal of thermal expansion control, the synthesis and properties of Sc{sub 1−x}Al{sub x}F{sub 3} were investigated. The solubility limit of AlF{sub 3} in ScF{sub 3} at ∼1340 K is ∼50%. Solid solutions (x≤0.50) were characterized by synchrotron powder diffraction at ambient pressure between 100 and 900 K and at pressures <0.414 GPa while heating from 298 to 523 K. A phase transition from cubic to rhombohedral is observed. The transition temperature increases smoothly with Al{sup 3+} content, approaching 500 K at the solid solubility limit, and also upon compression at fixed Al{sup 3+} content. The slope of the pressure–temperature phase boundary is ∼0.5 K MPa{sup −1}, which is steep relative to that for most symmetry-lowering phase transitions in perovskites. The volume coefficient of thermal expansion (CTE) for the rhombohedral phase is strongly positive, but the cubic-phase CTE varies from negative (x<0.15) to near-zero (x=0.15) to positive (x>0.20) between ∼600 and 800 K. The cubic solid solutions elastically stiffen on heating, while Al{sup 3+} substitution causes softening at a given temperature. - Graphical abstract: The cubic-phase coefficient of thermal expansion for Sc{sub 1−x}Al{sub x}F{sub 3}(solubility limit ∼50% at ∼1340 K) becomes more positive with increased Al{sup 3+} substitution, but the average isothermal bulk modulus decreases (elastic softening). - Highlights: • The solubility limit of AlF{sub 3} in ScF{sub 3} at ∼1340 K is ∼50%. • The phase transition temperature of Sc{sub 1−x}Al{sub x}F{sub 3} increases smoothly with x. • The cubic-phase volume CTE varies from negative to positive with increasing x. • The cubic solid solutions elastically stiffen on heating. • Al{sup 3+} substitution causes softening at a given temperature.

  14. Solvent-Free Polymerization of L-Aspartic Acid in the Presence of D-Sorbitol to Obtain Water Soluble or Network Copolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    L-aspartic acid was thermally polymerized in the presence of D-sorbitol with the goal of synthesizing new, higher molecular weight water soluble and absorbent copolymers. No reaction occurred when aspartic acid alone was heated at 170 or 200 degrees C. In contrast, heating sorbitol and aspartic ac...

  15. Soluble and cell wall-bound phenolic acids and ferulic acid dehydrodimers in rye flour and five bread model systems: insight into mechanisms of improved availability

    PubMed Central

    Dynkowska, Wioletta M; Cyran, Malgorzata R; Ceglińska, Alicja

    2015-01-01

    Background The bread-making process influences bread components, including phenolics that significantly contribute to its antioxidant properties. Five bread model systems made from different rye cultivars were investigated to compare their impact on concentration of ethanol-soluble (free and ester-bound) and insoluble phenolics. Results Breads produced by a straight dough method without acid addition (A) and three-stage sourdough method with 12 h native starter preparation (C) exhibited the highest, genotype-dependent concentrations of free phenolic acids. Dough acidification by direct acid addition (method B) or by gradual production during prolonged starter fermentation (24 and 48 h, for methods D and E) considerably decreased their level. However, breads B were enriched in soluble ester-bound fraction. Both direct methods, despite substantial differences in dough pH, caused a similar increase in the amount of insoluble ester-bound fraction. The contents of phenolic fractions in rye bread were positively related to activity level of feruloyl esterase and negatively to those of arabinoxylan-hydrolysing enzymes in wholemeal flour. Conclusion The solubility of rye bread phenolics may be enhanced by application of a suitable bread-making procedure with respect to rye cultivar, as the mechanisms of this process are also governed by a response of an individual genotype with specific biochemical profile. © 2014 Plant Breeding and Acclimatization Institute, National Research Institute. © 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25410263

  16. High abundances of water-soluble dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the mountain aerosols over the North China Plain during wheat burning season

    NASA Astrophysics Data System (ADS)

    Kawamura, K.; Tachibana, E.; Okuzawa, K.; Aggarwal, S. G.; Kanaya, Y.; Wang, Z. F.

    2013-02-01

    Aerosol (TSP) samples were collected at the summit of Mount Tai (elevation: 1534 m a.s.l., 36.25° N; 117.10° E) located in the North China Plain using a high-volume air sampler and pre-combusted quartz filters. Sampling was conducted on day/night or 3 h basis in the period from 29 May to 28 June 2006 during the field burning of wheat straw residue and the post-burning season. The filter samples were analyzed for low molecular weight dicarboxylic acids, ketoacids and α-dicarbonyls using capillary gas chromatography (GC) and GC-MS employing water extraction and butyl ester derivatization. Dicarboxylic acids (C2-C11, 220-6070 ng m-3) were characterized by a predominance of oxalic (C2) acid (105-3920 ng m-3) followed by succinic (C4) or malonic (C3) acid. Unsaturated aliphatic diacids, including maleic (M), isomaleic (iM) and fumaric (F) acid, were also detected together with aromatic diacids (phthalic, iso-phthalic and tere-phthalic acids). ω-Oxocarboxylic acids (C2-C9, 24-610 ng m-3) were detected as the second most abundant compound class with the predominance of glyoxylic acid (11-360 ng m-3), followed by α-ketoacid (pyruvic acid, 3-140 ng m-3) and α-dicarbonyls (glyoxal, 1-230 ng m-3 and methylglyoxal, 2-120 ng m-3). We found that these levels (> 6000 ng m-3 for diacids) are several times higher than those reported in Chinese megacities at ground levels. The concentrations of diacids increased from late May to early June showing a maximum on 7 June and then significantly decreased during 8-11 June when the wind direction shifted from northeasterly to northerly. Similar temporal trends were found for ketocarboxylic acids and α-dicarbonyls as well as total carbon (TC) and water-soluble organic carbon (WSOC). The temporal variations of water-soluble organics were interpreted by the direct emission from the field burning products of agricultural wastes (wheat straw) in the North China Plain and the subsequent photochemical oxidation of volatile and semi

  17. Conversion of solid dispersion prepared by acid-base interaction into free-flowing and tabletable powder by using Neusilin® US2.

    PubMed

    Shah, Ankita; Serajuddin, Abu T M

    2015-04-30

    A novel method of greatly increasing solubility and dissolution rate of a model basic drug, haloperidol, by interacting it with water-soluble weak organic acids in aqueous media was previously reported in the literature. Amorphous solid dispersion (SD) was formed when solutions containing haloperidol and various acids were dried. However, the SDs were semisolid, viscous and sticky, especially when the drug load was high, and could not be processed into tablets. The drug release from SD was also incomplete since the viscous material did not readily mix with aqueous media. In the present study, a mesoporous metalosilicate, Neusilin(®) US2, was incorporated in SDs prepared by using malic, tartaric and citric acids. The silicate constituted 40% w/w of the total solid mass. The addition of silicate converted SDs into powders, which were then characterized for flow properties, bulk and tap density, and tabletability. Their physical properties were found to be acceptable for the development of tablets. DSC and powder XRD showed that haloperidol and acids converted completely to amorphous forms, and they did not show any sign of crystallization during accelerated stability study at 40°C/75% RH and 25°C/60% RH for 9 months. Complete drug release under gastrointestinal pH conditions could be obtained from tablets prepared. PMID:25724137

  18. Conversion of solid dispersion prepared by acid-base interaction into free-flowing and tabletable powder by using Neusilin® US2.

    PubMed

    Shah, Ankita; Serajuddin, Abu T M

    2015-04-30

    A novel method of greatly increasing solubility and dissolution rate of a model basic drug, haloperidol, by interacting it with water-soluble weak organic acids in aqueous media was previously reported in the literature. Amorphous solid dispersion (SD) was formed when solutions containing haloperidol and various acids were dried. However, the SDs were semisolid, viscous and sticky, especially when the drug load was high, and could not be processed into tablets. The drug release from SD was also incomplete since the viscous material did not readily mix with aqueous media. In the present study, a mesoporous metalosilicate, Neusilin(®) US2, was incorporated in SDs prepared by using malic, tartaric and citric acids. The silicate constituted 40% w/w of the total solid mass. The addition of silicate converted SDs into powders, which were then characterized for flow properties, bulk and tap density, and tabletability. Their physical properties were found to be acceptable for the development of tablets. DSC and powder XRD showed that haloperidol and acids converted completely to amorphous forms, and they did not show any sign of crystallization during accelerated stability study at 40°C/75% RH and 25°C/60% RH for 9 months. Complete drug release under gastrointestinal pH conditions could be obtained from tablets prepared.

  19. Aircraft observations of water-soluble dicarboxylic acids in the aerosols over China

    NASA Astrophysics Data System (ADS)

    Zhang, Yan-Lin; Kawamura, Kimitaka; Qing Fu, Ping; Boreddy, Suresh K. R.; Watanabe, Tomomi; Hatakeyama, Shiro; Takami, Akinori; Wang, Wei

    2016-05-01

    Vertical profiles of dicarboxylic acids, related organic compounds and secondary organic aerosol (SOA) tracer compounds in particle phase have not yet been simultaneously explored in East Asia, although there is growing evidence that aqueous-phase oxidation of volatile organic compounds may be responsible for the elevated organic aerosols (OA) in the troposphere. Here, we found consistently good correlation of oxalic acid, the most abundant individual organic compounds in aerosols globally, with its precursors as well as biogenic-derived SOA compounds in Chinese tropospheric aerosols by aircraft measurements. Anthropogenically derived dicarboxylic acids (i.e., C5 and C6 diacids) at high altitudes were 4-20 times higher than those from surface measurements and even occasionally dominant over oxalic acid at altitudes higher than 2 km, which is in contrast to the predominance of oxalic acid previously reported globally including the tropospheric and surface aerosols. This indicates an enhancement of tropospheric SOA formation from anthropogenic precursors. Furthermore, oxalic acid-to-sulfate ratio maximized at altitudes of ˜ 2 km, explaining aqueous-phase SOA production that was supported by good correlations with predicted liquid water content, organic carbon and biogenic SOA tracers. These results demonstrate that elevated oxalic acid and related SOA compounds from both the anthropogenic and biogenic sources may substantially contribute to tropospheric OA burden over polluted regions of China, implying aerosol-associated climate effects and intercontinental transport.

  20. Pretreatment of dried distillers grains with solubles by soaking in aqueous ammonia and subsequent enzymatic/dilute acid hydrolysis to produce fermentable sugars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Formation of water-soluble dicarboxylic acids, oxoacids and a-dicarbonyls by ozone oxidation of isoprene

    NASA Astrophysics Data System (ADS)

    Kawamura, K.; Tachibana, E.; Sakamoto, Y.; Hirokawa, J.

    2014-12-01

    Water-soluble dicarboxylic acids such as oxalic acid (C2) are the dominant organic compound class in atmospheric aerosols. They can act as cloud condensation nuclei and affect on the Earth climate. Diacids can be primary emitted from fossil fuel combustion and biomass burning and secondarily produced by photochemical oxidations of biogenic and anthropogenic hydrocarbons. However, their sources and formation processes are still not well understood. Recently model and observation studies suggested the importance of isoprene as a precursor of oxalic acid. Isoprene is the most abundant BVOC emitted from terrestrial plants and can serve as important precursors of diacids. We conducted a laboratory oxidation of isoprene (2.0 ppm) with ozone (4.3 ppm) in a Teflon bag for 10 to 480 min. The formed particles were collected with quartz fiber filters and analyzed for diacids, oxoacids and a-dicarbonyls employing water extraction and butyl ester derivatization and using GC and GC/MS techniques. Here, we report the analytical results to better understand the formation process of diacids and related compounds from isoprene. We detected homologous series of saturated diacids (C2-C6), unsaturated diacids (maleic and methylmaleic acids), w-oxocarboxylic acids (C2-C9), pyruvic acid, glyoxal and methylglyoxal. We found that oxalic acid (3000-9700 ngm-3) is the most abundant diacid followed by succinic (C4) or malonic (C3) acid. Their concentrations increased with reaction time showing a maximum in 4 hours. Interestingly, C3/C4 ratios increased with time. The second most abundant species after oxalic acid was generally methylglyoxal (3600-9600 ngm-3), except for the 30 min. sample where methylglyoxal was more abundant than oxalic acid. Glyoxylic acid (wC2) was found as the most abundant oxoacid (1600-3800 ngm-3) followed by wC3 and wC4. Although the concentrations of diacids and related compounds are 1-2 orders magnitude higher than those reported in ambient aerosols, this study

  2. Defensive strategies in Geranium sylvaticum, Part 2: Roles of water-soluble tannins, flavonoids and phenolic acids against natural enemies.

    PubMed

    Tuominen, Anu

    2013-11-01

    Geranium sylvaticum is a common herbaceous plant in Fennoscandia, which has a unique phenolic composition. Ellagitannins, proanthocyanidins, galloylglucoses, gallotannins, galloyl quinic acids and flavonoids possess variable distribution in its different organs. These phenolic compounds are thought to have an important role in plant-herbivore interactions. The aim of this study was to quantify these different water-soluble phenolic compounds and measure the biological activity of the eight organs of G. sylvaticum. Compounds were characterized and quantified using HPLC-DAD/MS, in addition, total proanthocyanidins were determined by BuOH-HCl assay and total phenolics by the Folin-Ciocalteau method. Two in vitro biological activity measurements were used: the prooxidant activity was measured by the browning assay and antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Organ extracts were fractionated using column chromatography on Sephadex LH-20 and the activities of fractions was similarly measured to evaluate which polyphenol groups contributed the most to the biological activity of each organ. The data on the activity of fractions were examined by multivariate data analysis. The water-soluble extracts of leaves and pistils, which contained over 30% of the dry weight as ellagitannins, showed the highest pro-oxidant activity among the organ extracts. Fraction analysis revealed that flavonoids and galloyl quinic acids also exhibited high pro-oxidant activity. In contrast, the most antioxidant active organ extracts were those of the main roots and hairy roots that contained high amounts of proanthocyanidins in addition to ellagitannins. Analysis of the fractions showed that especially ellagitannins and galloyl quinic acids have high antioxidant activity. We conclude that G. sylvaticum allocates a significant amount of tannins in those plant parts that are important to the fitness of the plant and susceptible to natural enemies, i

  3. Novel in situ self-assembly nanoparticles for formulating a poorly water-soluble drug in oral solid granules, improving stability, palatability, and bioavailability

    PubMed Central

    Guo, Shujie; Pham, Kevin; Li, Diana; Penzak, Scott R; Dong, Xiaowei

    2016-01-01

    Purpose The purpose of this study was to develop a novel lipid-based nanotechnology to formulate poorly water-soluble drugs in oral solid granules to improve stability, palatability, and bioavailability. Materials and methods In one method, we prepared ritonavir (RTV) nanoparticles (NPs) by a microemulsion-precursor method and then converted the RTV NPs to solid granules by wet granulation to produce RTV NP-containing granules. In the other innovative method, we did not use water in the formulation preparation, and discovered novel in situ self-assembly nanoparticles (ISNPs). We prepared RTV ISNP granules that did not initially contain NPs, but spontaneously produced RTV ISNPs when the granules were introduced to water with gentle agitation. We fully characterized these RTV nanoformulations. We also used rats to test the bioavailability of RTV ISNP granules. Finally, an Astree electronic tongue was used to assess the taste of the RTV ISNP granules. Results RTV NP-containing granules only had about 1% drug loading of RTV in the solid granules. In contrast, RTV ISNP granules achieved over 16% drug loading and were stable at room temperature over 24 weeks. RTV ISNPs had particle size between 160 nm and 300 nm with narrow size distribution. RTV ISNPs were stable in simulated gastric fluid for 2 hours and in simulated intestinal fluid for another 6 hours. The data from the electronic tongue showed that the RTV ISNP granules were similar in taste to blank ISNP granules, but were much different from RTV solution. RTV ISNP granules increased RTV bioavailability over 2.5-fold compared to RTV solution. Conclusion We successfully discovered and developed novel ISNPs to manufacture RTV ISNP granules that were reconstitutable, stable, and palatable, and improved RTV bioavailability. The novel ISNP nanotechnology is a platform to manufacture oral solid dosage forms for poorly water-soluble drugs, especially for pediatric formulation development. PMID:27103803

  4. Sodium alginate as a potential carrier in solid dispersion formulations to enhance dissolution rate and apparent water solubility of BCS II drugs.

    PubMed

    Borba, Paola Aline Amarante; Pinotti, Marihá; de Campos, Carlos Eduardo Maduro; Pezzini, Bianca Ramos; Stulzer, Hellen Karine

    2016-02-10

    The solid dispersion technique is the most effective method for improving the dissolution rate of poorly water-soluble drugs, however it depends on a suitable carrier selection. The work explored the use of the biopolymer sodium alginate (SA) as a potential carrier in solid dispersions (SD). The data demonstrated that SA was able to improve the biopharmaceutical properties of the BCS II drug telmisartan (TEL) of low solubility even using relative small drug:polymer ratio. A solid state grinding process was used to prepare the solid dispersions (SD) during 45 min. The SD were prepared in different proportions of drug and carrier of 1:1, 1:3, 1:5, 1:7 and 1:9 (mass/mass). DSC, XRPD, FTIR and Raman confirmed the presence of molecular interactions between TEL and the carrier. FTIR supports the presence of hydrogen bonds between TEL and the carrier. SD_1:5, SD_1:7 and SD_1:9 enhanced the dissolution rate of the drug releasing more than 80% of the drug in just 30 min (83%, 84% and 87%). The the t-test results demonstrated equal dissolution efficiency values for SD_1:7 and Micardis(®), however the similarity (f2) and difference (f1) fit factors showed that the SD and Micardis(®) are statistically different. The physical stability studies demonstrated that SD using sodium alginate as a carrier remained unchanged during the period of 90 days at room temperature, showing that the sodium alginate acts as a good anti plasticizer agent, preventing the drug recrystallization. PMID:26686139

  5. Sodium alginate as a potential carrier in solid dispersion formulations to enhance dissolution rate and apparent water solubility of BCS II drugs.

    PubMed

    Borba, Paola Aline Amarante; Pinotti, Marihá; de Campos, Carlos Eduardo Maduro; Pezzini, Bianca Ramos; Stulzer, Hellen Karine

    2016-02-10

    The solid dispersion technique is the most effective method for improving the dissolution rate of poorly water-soluble drugs, however it depends on a suitable carrier selection. The work explored the use of the biopolymer sodium alginate (SA) as a potential carrier in solid dispersions (SD). The data demonstrated that SA was able to improve the biopharmaceutical properties of the BCS II drug telmisartan (TEL) of low solubility even using relative small drug:polymer ratio. A solid state grinding process was used to prepare the solid dispersions (SD) during 45 min. The SD were prepared in different proportions of drug and carrier of 1:1, 1:3, 1:5, 1:7 and 1:9 (mass/mass). DSC, XRPD, FTIR and Raman confirmed the presence of molecular interactions between TEL and the carrier. FTIR supports the presence of hydrogen bonds between TEL and the carrier. SD_1:5, SD_1:7 and SD_1:9 enhanced the dissolution rate of the drug releasing more than 80% of the drug in just 30 min (83%, 84% and 87%). The the t-test results demonstrated equal dissolution efficiency values for SD_1:7 and Micardis(®), however the similarity (f2) and difference (f1) fit factors showed that the SD and Micardis(®) are statistically different. The physical stability studies demonstrated that SD using sodium alginate as a carrier remained unchanged during the period of 90 days at room temperature, showing that the sodium alginate acts as a good anti plasticizer agent, preventing the drug recrystallization.

  6. Solubility and equilibrium vapor pressures of HC1 dissolved in polar stratospheric cloud materials - Ice and the trihydrate of nitric acid

    NASA Technical Reports Server (NTRS)

    Hanson, David; Mauersberger, Konrad

    1988-01-01

    Measurements of the pressure-solubility behavior of HC1 in water ice and in the nitric acid trihydrate (NAT) crystal at 200 K are reported. It was found that HC1 is about 20 times more soluble in NAT than in ice for stratospheric conditions. A relation between HC1 pressure and substrate composition based on the Gibbs-Duhem equation is developed. This relation, along with other thermodynamic data, can be used to obtain the HC1 pressure-solubility behavior at different temperatures. Implications of these results for the south polar ozone hole are discussed.

  7. Release of a Poorly Soluble Drug from Hydrophobically Modified Poly (Acrylic Acid) in Simulated Intestinal Fluids

    PubMed Central

    Knöös, Patrik

    2015-01-01

    A large part of new pharmaceutical substances are characterized by a poor solubility and high hydrophobicity, which might lead to a difference in drug adsorption between fasted and fed patients. We have previously evaluated the release of hydrophobic drugs from tablets based on Pemulen TR2 and showed that the release can be manipulated by adding surfactants. Here we further evaluate the possibility to use Pemulen TR2 in controlled release tablet formulations containing a poorly soluble substance, griseofulvin. The release is evaluated in simulated intestinal media that model the fasted state (FaSSIF medium) or fed state (FeSSIF). The rheology of polymer gels is studied in separate experiments, in order to gain more information on possible interactions. The release of griseofulvin in tablets without surfactant varied greatly and the slowest release were observed in FeSSIF. Addition of SDS to the tablets eliminated the differences and all tablets showed a slow linear release, which is of obvious relevance for robust drug delivery. Comparing the data from the release studies and the rheology experiment showed that the effects on the release from the different media could to a large extent be rationalised as a consequence of the interactions between the polymer and the surfactants in the media. The study shows that Pemulen TR2 is a candidate for controlled release formulations in which addition of surfactant provides a way to eliminate food effects on the release profile. However, the formulation used needs to be designed to give a faster release rate than the tablets currently investigated. PMID:26473964

  8. Redox-controlled changes in cadmium solubility and solid-phase speciation in a paddy soil as affected by reducible sulfate and copper.

    PubMed

    Fulda, Beate; Voegelin, Andreas; Kretzschmar, Ruben

    2013-11-19

    The solubility of Cd in contaminated paddy soils controls Cd uptake by rice, which is an important food safety issue. We investigated the solution and solid-phase dynamics of Cd in a paddy soil spiked with ∼20 mg kg(-1) Cd during 40 days of soil reduction followed by 28 days of soil reoxidation as a function of the amounts of sulfate available for microbial reduction and of Cu that competes with Cd for precipitation with biogenic sulfide. At an excess of sulfate over (Cd + Cu), dissolved Cd decreased during sulfate reduction and Cd was transformed into a poorly soluble phase identified as Cd-sulfide using Cd K-edge X-ray absorption spectroscopy (XAS). The extent of Cd-sulfide precipitation decreased with decreasing sulfate and increasing Cu contents, even if sulfate exceeded Cd. When both Cu and Cd exceeded sulfate, dissolved and mobilizable Cd remained elevated after 40 days of soil reduction. During soil reoxidation, Cd-sulfide was readily transformed back into more soluble species. Our data suggest that Cd-sulfide formation in flooded paddy soil may be limited when the amounts of Cd and other chalcophile metals significantly exceed reducible sulfate Therefore, in multimetal contaminated paddy soils with low sulfate contents, Cd may remain labile during soil flooding, which enhances the risk for Cd transfer into rice. PMID:24171446

  9. Clay Minerals as Solid Acids and Their Catalytic Properties.

    ERIC Educational Resources Information Center

    Helsen, J.

    1982-01-01

    Discusses catalytic properties of clays, attributed to acidity of the clay surface. The formation of carbonium ions on montmorillonite is used as a demonstration of the presence of surface acidity, the enhanced dissociation of water molecules when polarized by cations, and the way the surface can interact with organic substances. (Author/JN)

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

    PubMed

    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.

  11. J-aggregation of a water-soluble tetracationic porphyrin in mixed LB films with a calix[8]arene carboxylic acid derivative.

    PubMed

    Miguel, Gustavo de; Pérez-Morales, Marta; Martín-Romero, María T; Muñoz, Eulogia; Richardson, Tim H; Camacho, Luis

    2007-03-27

    The molecular organization of a mixed film, containing a water-soluble tetracationic porphyrin (TMPyP) and a p-tert-butyl calix[8]arene octacarboxylic acid derivative (C8A), at the air-water interface and on a solid support (LB film), has been investigated. Although the TMPyP aggregation was not detected at the air-water interface, TMPyP J-aggregates have been found in the LB films (Y-type). Unlike tetraanionic porphyrins, for example TSPP, the TMPyP J-aggregates are not induced by a zwitterion formation. The TMPyP J-aggregation is a result of a "double comb" configuration, where porphyrins from opposite layers are interwoven in a linear infinite J-aggregate. Our results confirm that TMPyP molecules tend to self-aggregate strongly, provided the electrostatic repulsions of their peripheral groups are cancelled by the anionic groups of the C8A matrix. PMID:17315895

  12. Modeling solubility, acid-base properties and activity coefficients of amoxicillin, ampicillin and (+)6-aminopenicillanic acid, in NaCl(aq) at different ionic strengths and temperatures.

    PubMed

    Crea, Francesco; Cucinotta, Daniela; De Stefano, Concetta; Milea, Demetrio; Sammartano, Silvio; Vianelli, Giuseppina

    2012-11-20

    The total solubility of three penicillin derivatives was determined, in pure water and NaCl aqueous solutions at different salt concentrations (from ∼0.15 to 1.0 mol L(-1) for ampicillin and amoxicillin, and from ∼0.05 to 2.0 mol L(-1) for (+)6-aminopenicillanic acid), using the shake-flask method for generating the saturated solutions, followed by potentiometric analysis. The knowledge of the pH of solubilization and of the protonation constants determined in the same experimental conditions, allowed us to calculate, by means of the mass balance equations, the solubility of the neutral species at different ionic strength values, to model its dependence on the salt concentration and to determine the corresponding values at infinite dilution. The salting parameter and the activity coefficients of the neutral species were calculated by the Setschenow equation. The protonation constants of ampicillin and amoxicillin, determined at different temperatures (from T=288.15 to 318.15K), from potentiometric and spectrophotometric measurements, were used to calculate, by means of the Van't Hoff equation, the temperature coefficients at different ionic strength values and the corresponding protonation entropies. The protonation enthalpies of the (+)6-aminopenicillanic acid were determined by isoperibol calorimetric titrations at T=298.15K and up to I=2.0 mol L(-1). The dependence of the protonation constants on ionic strength was modeled by means of the Debye-Hückel and SIT (Specific ion Interaction Theory) approaches, and the specific interaction parameters of the ionic species were determined. The hydrolysis of the β-lactam ring was studied by spectrophotometric and H NMR investigations as a function of pH, ionic strength and time. Potentiometric measurements carried out on the hydrolyzed (+)6-aminopenicillanic acid allowed us to highlight that the opened and the closed β-lactam forms of the (+)6-aminopenicillanic acid have quite different acid-base properties. An

  13. Boronic acid as an efficient anchor group for surface modification of solid polyvinyl alcohol.

    PubMed

    Nishiyabu, Ryuhei; Shimizu, Ai

    2016-07-28

    We report the use of boronic acid as an anchor group for surface modification of solid polyvinyl alcohol (PVA); the surfaces of PVA microparticles, films, and nanofibers were chemically modified with boronic acid-appended fluorescent dyes through boronate esterification using a simple soaking technique in a short time under ambient conditions. PMID:27311634

  14. Effects of marine n-3 fatty acids on circulating levels of soluble adhesion molecules in patients with chronic heart failure.

    PubMed

    Eschen, O; Christensen, J H; LA Rovere, M T; Romano, P; Sala, P; Schmidt, E B

    2010-01-01

    Inflammatory markers as circulating soluble cellular adhesion molecules (sCAMs) and high sensitive C-reactive protein (hsCRP) are elevated in patients with chronic heart failure (CHF), and may constitute an increased risk of adverse outcome. Marine n-3 polyunsaturated fatty acids ( n-3 PUFA) may have anti-inflammatory effect and reduce levels of sCAMs (soluble intercellular adhesion molecule-1 (sICAM-1), vascular adhesion molecule-1 (sVCAM-1), P-selectin) and hsCRP. In a randomized, controlled trial, 138 patients with NYHA class II-III CHF were allocated to receive a daily supplement of 0.9 g of n-3 PUFA or olive oil for 24 weeks. After supplementation, no significant changes occurred in sCAMs or hsCRP after adjusting for possible confounders. However, a significant reduction was observed in sP-selectin in patients receiving n-3 PUFA, but this result was only of borderline significance in a between-group analysis. In conclusion, a daily supplement with 0.9 g of n-3 PUFA does not significantly affect plasma levels of sCAMs or hs-CRP in patients with CHF. n-3 PUFA may reduce sP-selectin, indicating a possible effect on platelet (and endothelial) activation. The results also indicate that the low dose of n-3 PUFA used in many intervention trials does not have deleterious effects on sCAMs or hsCRP.

  15. Cotton wool-like poly(lactic acid)/vaterite composite scaffolds releasing soluble silica for bone tissue engineering.

    PubMed

    Obata, Akiko; Ozasa, Hiroki; Kasuga, Toshihiro; Jones, Julian R

    2013-07-01

    Cotton wool-like poly(L-lactic acid) and siloxane-doped vaterite (SiV) composite scaffolds were prepared with a modified electrospinning system for bone tissue engineering applications. The effects of changing the SiV content in the materials from 10 to 30 wt% on elasticity and the ability to release calcium ions and soluble silica were evaluated. The elasticity of the cotton wool-like composites was almost the same as that of the PLLA from the results of compressibility and recovery tests. The materials released calcium ions for more than 56 days and soluble silica for 28-56 days in a tris buffer solution (pH 7.4). Mouse osteoblast-like cells (MC3T3-E1 cells) were cultured on/in the cotton wool-like materials or the fibremats out of the same composite materials as that used for the cotton wool-like materials. The cells penetrated into and proliferated inside the cotton wool-like materials, although they mainly adhered on the fibremat surface.

  16. Preparation and physicochemical properties of soluble dietary fiber from orange peel assisted by steam explosion and dilute acid soaking.

    PubMed

    Wang, Lei; Xu, Honggao; Yuan, Fang; Fan, Rui; Gao, Yanxiang

    2015-10-15

    The coupled pretreatment of orange peel with steam explosion (SE) and sulfuric-acid soaking (SAS) was investigated to enhance the yield and improve the functionality of soluble dietary fiber (SDF). When orange peel was pretreated by SE at 0.8MPa for 7 min, combined with 0.8% SAS, the content of SDF was increased from 8.04% to 33.74% in comparison to the control and SDF prepared with SE-SAS showed the high water solubility, water-holding capacity, oil-holding capacity, swelling capacity, emulsifying activity, emulsion stability and foam stability. SDF from orange peel treated by SE-SAS exhibited significantly (p < 0.05) higher binding capacity for three toxic cations (Pb, As and Cu) and smaller molecular weight (Mw = 174 kDa). Furthermore, differential scanning calorimetry (DSC) measurement showed that SDF from orange peel treated by SE-SAS had a higher peak temperature (170.7 ± 0.4 °C) than that of the untreated sample (163.4 ± 0.3 °C). Scanning electron micrograph (SEM) images demonstrated that the surface of SDF from orange peel treated by SE-SAS was rough and collapsed. It can be concluded that SDF from orange peel treated by SE-SAS has the higher potential to be applied as a functional ingredient in food products.

  17. Preparation and physicochemical properties of soluble dietary fiber from orange peel assisted by steam explosion and dilute acid soaking.

    PubMed

    Wang, Lei; Xu, Honggao; Yuan, Fang; Fan, Rui; Gao, Yanxiang

    2015-10-15

    The coupled pretreatment of orange peel with steam explosion (SE) and sulfuric-acid soaking (SAS) was investigated to enhance the yield and improve the functionality of soluble dietary fiber (SDF). When orange peel was pretreated by SE at 0.8MPa for 7 min, combined with 0.8% SAS, the content of SDF was increased from 8.04% to 33.74% in comparison to the control and SDF prepared with SE-SAS showed the high water solubility, water-holding capacity, oil-holding capacity, swelling capacity, emulsifying activity, emulsion stability and foam stability. SDF from orange peel treated by SE-SAS exhibited significantly (p < 0.05) higher binding capacity for three toxic cations (Pb, As and Cu) and smaller molecular weight (Mw = 174 kDa). Furthermore, differential scanning calorimetry (DSC) measurement showed that SDF from orange peel treated by SE-SAS had a higher peak temperature (170.7 ± 0.4 °C) than that of the untreated sample (163.4 ± 0.3 °C). Scanning electron micrograph (SEM) images demonstrated that the surface of SDF from orange peel treated by SE-SAS was rough and collapsed. It can be concluded that SDF from orange peel treated by SE-SAS has the higher potential to be applied as a functional ingredient in food products. PMID:25952845

  18. SOLUBLE HEPATIC δ-AMINOLEVULINIC ACID SYNTHETASE: END-PRODUCT INHIBITION OF THE PARTIALLY PURIFIED ENZYME*

    PubMed Central

    Scholnick, Perry L.; Hammaker, Lydia E.; Marver, Harvey S.

    1969-01-01

    The present study confirms the existence of hepatic δ-aminolevulinic acid synthetase in the cytosol of the liver, suggests that this enzyme may be in transit to the mitochondria, and defines some of the characteristics of the partially purified enzyme. The substrate and cofactor requirements are similar to those of mitochondrial δ-aminolevulinic acid synthetase. Heme strongly inhibits the partially purified enzyme. A number of proteins that bind heme block this inhibition, which explains previous failures to demonstrate heme inhibition in crude systems. End-product inhibition of δ-aminolevulinic acid synthetase in the mitochondria may play an important role in the regulation of heme biosynthesis in eukaryotic cells. PMID:5257968

  19. Water-Soluble Poly(p-aryleneethynylene)s: A Sensor Array Discriminates Aromatic Carboxylic Acids.

    PubMed

    Han, Jinsong; Wang, Benhua; Bender, Markus; Seehafer, Kai; Bunz, Uwe H F

    2016-08-10

    A chemical tongue consisting of 11 elements (four poly(p-aryleneethynylene)s (PAE) at pH 7 and pH 13, and seven electrostatic complexes formed from oppositely charged poly(p-aryleneethynylene)s at pH 7) discriminate 21 benzoic and phenylacetic acid derivatives in aqueous solution. The mechanism of discrimination is the fluorescence modulation of the PAEs, leading to quenching or fluorescence turn-on. The PAEs alone at both pH values and the tongue, consisting of the complexes only, discriminate the 21 acids with 92% (PAEs at pH 7), 95% (PAEs at pH 13), and 99% (complexes at pH 7) reliability after linear discriminant analysis (LDA). A sensor field with all 14 elements, according to LDA, discriminates all of the 21 acids with 100% accuracy. PMID:27415439

  20. Unexpected solvent impact in the crystallinity of praziquantel/poly(vinylpyrrolidone) formulations. A solubility, DSC and solid-state NMR study.

    PubMed

    Costa, Emanuel D; Priotti, Josefina; Orlandi, Silvina; Leonardi, Darío; Lamas, María C; Nunes, Teresa G; Diogo, Hermínio P; Salomon, Claudio J; Ferreira, M João

    2016-09-25

    The saturation solubility of PVP:PZQ physical mixtures (PMs) and solid dispersions (SDs) prepared from ethanol (E/E) or ethanol/water (E/W) by the solvent evaporation method at 1:1, 2:1 and 3:1 ratio (w/w) was determined. The presence of PVP improves the solubility of PZQ (0.31±0.01mg/mL). A maximum of 1.29±0.03mg/mL of PZQ in solution was achieved for the 3:1 SD (E/E). The amount of PZQ in solution depends on the amount of polymer and on the preparation method. Solid-state NMR (ssNMR) and DSC were used to understand this behavior. Results show that PMs are a mixture of crystalline PZQ with the polymer, while SDs show different degrees of drug amorphization depending on the solvent used. For E/W SDs, PZQ exists in amorphous and crystalline states, with no clear correlation between the amount of crystalline PZQ and the amount of PVP. For E/E SDs, formulations with a higher percentage of PZQ are amorphous with the components miscible in domains larger than 3nm ((1)H ssNMR relaxation measurements). Albeit its higher saturation solubility, the 3:1 E/E PVP:PZQ sample has a significant crystalline content, probably due to the water introduced by the polymer. High PVP content and small crystal size account for this result. PMID:27506511

  1. Fermentation of municipal primary sludge: effect of SRT and solids concentration on volatile fatty acid production.

    PubMed

    Bouzas, A; Gabaldón, C; Marzal, P; Penya-Roja, J M; Seco, A

    2002-08-01

    Laboratory bench-scale experiments were conducted to investigate the performance of primary sludge fermentation for volatile fatty acids production. Primary sludges from two major wastewater treatment plants located in Valencia (Pinedo and Carraixet) were used. Experiments were performed at solids retention times between 4 and 10 days, and total volatile solids concentrations between 0.6% and 2.8%. Operation at two temperatures (20 degrees C and 30 degrees C) was also checked. Results indicated the importance of feed sludge characteristics on volatile fatty acids yields, being approximately double for the Carraixet wastewater treatment plant sludge than for the Pinedo plant. In both cases, higher volatile fatty acids yields were observed at higher total volatile solids concentrations. Solids retention times above 6 days scarcely improve volatile fatty acids yields, while experiments conducted at 4 days of solids retention times show an important decrease in volatile fatty acids yields. On raising temperature an increase in volatile fatty acids yields was observed, mainly due to an improvement in the hydrolysis of particulate organic matter.

  2. Activation of Carbonyl-Containing Molecules with Solid Lewis Acids in Aqueous Media

    SciTech Connect

    Román-Leshkov, Yuriy; Davis, Mark E.

    2011-09-28

    Current interest in reacting carbonyl-containing molecules in aqueous media is primarily due to the growing emphasis on conversion of biomass to fuels and chemicals. Recently, solid Lewis acids have been shown to perform catalytic reactions with carbonyl-containing molecules such as sugars in aqueous media. Here, catalysis mediated by Lewis acids is briefly discussed, Lewis acid solids that perform catalysis in aqueous media are then described, and the review is concluded with a few comments on the outlook for the future.

  3. The role of small acid-soluble proteins (SASPs) in protection of spores of Clostridium botulinum against nitrous acid.

    PubMed

    Meaney, Carolyn A; Cartman, Stephen T; McClure, Peter J; Minton, Nigel P

    2016-01-01

    Mutant strains of Clostridium botulinum ATCC 3502 were generated using the ClosTron in four genes (CBO1789, CBO1790, CBO3048, CBO3145) identified as encoding α/β-type SASP homologues. The spores of mutant strains in which CBO1789 or CBO1790 was inactivated demonstrated a significant increase in sensitivity to the damaging agent nitrous acid (P<0.01), a phenotype that was partially restored to wild-type in complementation studies. In contrast to nitrous acid, the spores of the CBO1789 and CBO1790 mutants showed no change in their resistance to formaldehyde and hydrogen peroxide (P>0.05), two other chemicals commonly used as components of disinfection regimes. These data indicate that the SASPs CBO1789 or CBO1790 play a significant role in resistance to nitrous acid, but not in resistance to formaldehyde or hydrogen peroxide.

  4. The role of small acid-soluble proteins (SASPs) in protection of spores of Clostridium botulinum against nitrous acid.

    PubMed

    Meaney, Carolyn A; Cartman, Stephen T; McClure, Peter J; Minton, Nigel P

    2016-01-01

    Mutant strains of Clostridium botulinum ATCC 3502 were generated using the ClosTron in four genes (CBO1789, CBO1790, CBO3048, CBO3145) identified as encoding α/β-type SASP homologues. The spores of mutant strains in which CBO1789 or CBO1790 was inactivated demonstrated a significant increase in sensitivity to the damaging agent nitrous acid (P<0.01), a phenotype that was partially restored to wild-type in complementation studies. In contrast to nitrous acid, the spores of the CBO1789 and CBO1790 mutants showed no change in their resistance to formaldehyde and hydrogen peroxide (P>0.05), two other chemicals commonly used as components of disinfection regimes. These data indicate that the SASPs CBO1789 or CBO1790 play a significant role in resistance to nitrous acid, but not in resistance to formaldehyde or hydrogen peroxide. PMID:26386202

  5. Soluble species in the Arctic summer troposphere: Acidic gases, aerosols, and precipitation

    NASA Astrophysics Data System (ADS)

    Talbot, R. W.; Vijgen, A. S.; Harriss, R. C.

    1992-10-01

    We report here the distribution of selected acidic gases and aerosol species in the North American Arctic and sub-Arctic summer troposphere. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases and acidic sulfate aerosols dominating the particulate phase. Our data show that the acidic gas and aerosol composition is uniform on a large spatial scale. There appears to be a surface source of NH4+ over the Arctic Ocean pack ice which may reflect release of NH3 from decay of dead marine organisms on the ice surface near ice leads, release from rotting sea ice, or an upward flux from surface ocean waters in open ice leads. This NH3 appears to partially neutralize aerosol acidity in the boundary layer. Over sub-Arctic tundra in southwestern Alaska inputs of marine biogenic sulfur from the nearby Bering Sea appear to be an important source of boundary layer aerosol SO42-. While there were only minor effects on aerosol chemistry over the tundra from sea salt, the rainwater chemistry showed influence from marine aerosols which were apparently incorporated into air masses during frontal passages moving inland from the Bering Sea. The rainwater acidity over the tundra (pH 4.69) is typical of remote regions. The principal acidity components are H2SO4 and carboxylic acids, especially HCOOH. The carboxylic acids appear to have a strong continental biogenic source, but hydrocarbons of marine origin and emissions from forest fires may also be important. The wet deposition fluxes of NO3--N and SO42--S over sub-Arctic tundra during July-August 1988 were 2.1 and 2.4 mmol m-2 yr-1. Wet deposition of NO3- was nearly 3 times higher than the average NOy deposition flux, which is believed to represent primarily dry deposition of HNO3 (Bakwin et al., this issue). Our measurements indicate that the mid-troposphere in the Arctic is generally contaminated with low levels of anthropogenic pollutants even in summer when direct atmospheric coupling

  6. Phytase activity of lactic acid bacteria and their impact on the solubility of minerals from wholemeal wheat bread.

    PubMed

    Cizeikiene, Dalia; Juodeikiene, Grazina; Bartkiene, Elena; Damasius, Jonas; Paskevicius, Algimantas

    2015-01-01

    The objective of this study was to determinate phytase activity of bacteriocins producing lactic acid bacteria previously isolated from spontaneous rye sourdough. The results show that the highest extracellular phytase activity produces Pediococcus pentosaceus KTU05-8 and KTU05-9 strains with a volumetric phytase activity of 32 and 54 U/ml, respectively, under conditions similar to leavening of bread dough (pH 5.5 and 30 °C). In vitro studies in simulated gastrointestinal tract media pH provide that bioproducts prepared with P. pentosaceus strains used in wholemeal wheat bread preparation increase solubility of iron, zinc, manganese, calcium and phosphorus average 30%. Therefore, P. pentosaceus KTU05-9 and KTU05-8 strains could be recommended to use as a starter for sourdough preparation for increasing of mineral bioavailability from wholemeal wheat bread.

  7. Histidine-functionalized water-soluble nanoparticles for biomimetic nucleophilic/general-base catalysis under acidic conditions.

    PubMed

    Chadha, Geetika; Zhao, Yan

    2013-10-21

    Cross-linking the micelles of 4-dodecyloxybenzyltripropargylammonium bromide by 1,4-diazidobutane-2,3-diol in the presence of azide-functionalized imidazole derivatives yielded surface-cross-linked micelles (SCMs) with imidazole groups on the surface. The resulting water-soluble nanoparticles were found, by fluorescence spectroscopy, to contain hydrophobic binding sites. The imidazole groups promoted the photo-deprotonation of 2-naphthol at pH 6 and catalyzed the hydrolysis of p-nitrophenylacetate (PNPA) in aqueous solution at pH ≥ 4. Although the overall hydrolysis rate slowed down with decreasing solution pH, the catalytic effect of the imidazole became stronger because the reactions catalyzed by unfunctionalized SCMs slowed down much more. The unusual ability of the imidazole–SCMs to catalyze the hydrolysis of PNPA under acidic conditions was attributed to the local hydrophobicity and the positive nature of the SCMs.

  8. Phytase activity of lactic acid bacteria and their impact on the solubility of minerals from wholemeal wheat bread.

    PubMed

    Cizeikiene, Dalia; Juodeikiene, Grazina; Bartkiene, Elena; Damasius, Jonas; Paskevicius, Algimantas

    2015-01-01

    The objective of this study was to determinate phytase activity of bacteriocins producing lactic acid bacteria previously isolated from spontaneous rye sourdough. The results show that the highest extracellular phytase activity produces Pediococcus pentosaceus KTU05-8 and KTU05-9 strains with a volumetric phytase activity of 32 and 54 U/ml, respectively, under conditions similar to leavening of bread dough (pH 5.5 and 30 °C). In vitro studies in simulated gastrointestinal tract media pH provide that bioproducts prepared with P. pentosaceus strains used in wholemeal wheat bread preparation increase solubility of iron, zinc, manganese, calcium and phosphorus average 30%. Therefore, P. pentosaceus KTU05-9 and KTU05-8 strains could be recommended to use as a starter for sourdough preparation for increasing of mineral bioavailability from wholemeal wheat bread. PMID:26397032

  9. Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid

    NASA Astrophysics Data System (ADS)

    Ehn, M.; Petäjä, T.; Aufmhoff, H.; Aalto, P.; Hämeri, K.; Arnold, F.; Laaksonen, A.; Kulmala, M.

    2006-10-01

    Freshly formed atmospheric aerosol particles are neither large enough to efficiently scatter incoming solar radiation nor able to act as cloud condensation nuclei. As the particles grow larger, their hygroscopicity determines the limiting size after which they are important in both of the aforementioned processes. The condensing species resulting in growth alter the hygroscopicity of the particles. We have measured hygroscopic growth of aerosol particles present in a boreal forest, along with the very hygroscopic atmospheric trace gas sulfuric acid. The focus was on days with new particle formation by nucleation. The measured hygroscopic growth factors (GF) correlated positively with gaseous phase sulfuric acid concentrations. This correlation had a strong size dependency; the smaller the particle, the more condensing sulfuric acid is bound to alter the GF due to initially smaller mass. In addition, water uptake of nucleation mode particles was monitored during new particle formation events and followed during their growth to Aitken mode sizes. As the modal diameter increased, the solubility of the particles decreased. This indicated that initially more hygroscopic particles transformed into less hygroscopic or even hydrophobic particles. A similar behavior was seen also during days with no particle formation, with GF decreasing during the evenings and increasing during early morning. This can be tentatively explained by day- and nighttime differences in the hygroscopicity of condensable vapors.

  10. Fatty acids and fat-soluble vitamins in ewe's milk predicted by near infrared reflectance spectroscopy. Determination of seasonality.

    PubMed

    Revilla, I; Escuredo, O; González-Martín, M I; Palacios, C

    2017-01-01

    The aim of the present work was to determine the fatty acid and fat-soluble vitamin composition and the season of ewe's milk production using NIR spectroscopy. 219 ewe's milk samples from different breeds and feeding regimes were taken each month over one year. Fatty acids were analyzed by gas chromatography, and retinol and α-, and γ-tocopherol by liquid chromatography. The results showed that the quantification was more accurate for the milk dried on paper, except for vitamins. Calibration statistical descriptors on milk dried on paper were good for capric, lauric, myristic, palmitoleic, stearic and oleic acids, and acceptable for caprilic, undecanoic, 9c, 11tCLA, ΣCLA, PUFA, ω3, ω6, retinol and α-tocopherol. The equations for the discrimination of seasonality was obtained using the partial least squares discriminant analysis (PLSDA) algorithm. 93% of winter samples and 89% of summer samples were correctly classified using the NIR spectra of milk dried on paper. PMID:27507500

  11. Prevention of bovine mastitis by a postmilking teat disinfectant containing chlorous acid and chlorine dioxide in a soluble polymer gel.

    PubMed

    Oliver, S P; King, S H; Torre, P M; Shull, E P; Dowlen, H H; Lewis, M J; Sordillo, L M

    1989-11-01

    A natural exposure study was conducted in a herd of 150 lactating dairy cows for 18 mo to determine the effectiveness of chlorous acid and chlorine dioxide in a soluble polymer gel as a postmilking teat disinfectant for the prevention of bovine mastitis. Right quarters of cows were dipped in the experimental teat dip after milking machine removal. Left quarters were not dipped and served as within-cow negative controls. The experimental teat dip reduced Staphylococcus aureus infections 67.4%, Streptococcus dysgalactiae infections 63.8%, and Streptococcus uberis infections 27.8%. Overall efficacy of the chlorous acid and chlorine dioxide teat dip against major mastitis pathogens was 52.2%. The experimental teat dip reduced Corynebacterium bovis infections and coagulase-negative staphylococcal infections also by 45.8 and 38.7%, respectively. Overall efficacy against minor mastitis pathogens was 43.4%. Under conditions of this trial, the experimental teat dip containing chlorous acid and chlorine dioxide was effective in preventing new intramammary infections against a variety of mastitis pathogens. PMID:2625499

  12. MOF-Derived Tungstated Zirconia as Strong Solid Acids toward High Catalytic Performance for Acetalization.

    PubMed

    Wang, Peng; Feng, Jian; Zhao, Yupei; Wang, Shaobin; Liu, Jian

    2016-09-14

    A strong solid acid, tungstated zirconia (WZ), has been prepared first using tungstate immobilized UiO-66 as precursors through a "double-solvent" impregnation method under mild calcination temperature. With moderate W contents, the as-synthesized WZ catalysts possess a high density of acid sites, and the proper heat treatment also has facilely led to a bunch of oligomeric tungsten clusters on stabilized tetragonal ZrO2. The resultant solid acids show an improved catalytic performance toward the benzaldehyde's acetalization in comparison with traditional zirconium hydroxide-prepared WZ. Notably, due to large surface area and additionally introduced strong acid sites, the MOF-derived WZ catalysts afforded conversion up to 86.0%. The facile method endows the WZ catalysts with superior catalytic activities and excellent recyclability, thus opening a new avenue for preparation of metal oxide-based solid superacids and superbases. PMID:27557351

  13. Solid-state NMR Study Reveals Collagen I Structural Modifications of Amino Acid Side Chains upon Fibrillogenesis*

    PubMed Central

    De Sa Peixoto, Paulo; Laurent, Guillaume; Azaïs, Thierry; Mosser, Gervaise

    2013-01-01

    In vivo, collagen I, the major structural protein in human body, is found assembled into fibrils. In the present work, we study a high concentrated collagen sample in its soluble, fibrillar, and denatured states using one and two dimensional {1H}-13C solid-state NMR spectroscopy. We interpret 13C chemical shift variations in terms of dihedral angle conformation changes. Our data show that fibrillogenesis increases the side chain and backbone structural complexity. Nevertheless, only three to five rotameric equilibria are found for each amino acid residue, indicating a relatively low structural heterogeneity of collagen upon fibrillogenesis. Using side chain statistical data, we calculate equilibrium constants for a great number of amino acid residues. Moreover, based on a 13C quantitative spectrum, we estimate the percentage of residues implicated in each equilibrium. Our data indicate that fibril formation greatly affects hydroxyproline and proline prolyl pucker ring conformation. Finally, we discuss the implication of these structural data and propose a model in which the attractive force of fibrillogenesis comes from a structural reorganization of 10 to 15% of the amino acids. These results allow us to further understand the self-assembling process and fibrillar structure of collagen. PMID:23341452

  14. Dual strategies to improve oral bioavailability of oleanolic acid: Enhancing water-solubility, permeability and inhibiting cytochrome P450 isozymes.

    PubMed

    Jiang, Qikun; Yang, Xiaoxu; Du, Ping; Zhang, Huifen; Zhang, Tianhong

    2016-02-01

    Oleanolic acid (OA) is a typical BCS IV drug with low water-solubility and poor permeability, metabolized by cytochrome P450 (CYP) isozymes in the intestinal tract, such as CYP3A. These are the reasons for the low oral bioavailability of OA which have restricted its wide application. In this study, a solidified phospholipid complex (OPCH) composed of OA-phospholipid complex (OPC) and hydroxyapatite (HA) was prepared by simple solvent evaporation. OPC was used to improve the liposolubility of OA, and HA was used to improve the flowability of OPC. Ketoconazole (KCZ, inhibitor of CYP3A) was co-administrated with OPCH to inhibit the metabolism of OA by CYP3A in the intestine. DSC, PXRD, SEM and IR analysis confirmed the formation of OPC and OPCH. Compared with the water-solubility and n-octanol solubility of OA, that of OPCH was increased nearly 15.3-fold and 3.19-fold, respectively. An in vitro dissolution study showed that the cumulative dissolution rate of OPCH was nearly 2.23-fold and 4.57-fold higher than that of OA and OPC at 2h. Single-pass intestinal perfusion studies showed that the absorption of OA from OPCH was increased nearly 1.6-2.6-fold compared with that of pure OA and this was mainly due to the improved permeability and was further increased by OPCH with KCZ 1.2-2.4-fold compared with that of OPCH because KCZ inhibited metabolism of OA by CYP3A. A pharmacokinetic study of OPCH in rats following co-administration of KCZ was investigated. The Cmax was increased markedly from 59.5 to 78.7 and 131.3ng/mL in case of OA alone, OPCH alone and OPCH with KCZ. In parallel with the Cmax, the AUC0-24h was increased from 259.6 to 306.6 and 707.7ngh/mL, respectively. All the results obtained demonstrated that formulation of OPCH and co-administration of KCZ significantly improved the bioavailability of OA by increasing the solubility and permeability in combination with inhibiting the metabolism of OA.

  15. Polydopamine-coated magnetic molecularly imprinted polymer for the selective solid-phase extraction of cinnamic acid, ferulic acid and caffeic acid from radix scrophulariae sample.

    PubMed

    Yin, Yuli; Yan, Liang; Zhang, Zhaohui; Wang, Jing; Luo, Ningjing

    2016-04-01

    We describe novel cinnamic acid polydopamine-coated magnetic imprinted polymers for the simultaneous selective extraction of cinnamic acid, ferulic acid and caffeic acid from radix scrophulariae sample. The novel magnetic imprinted polymers were synthesized by surface imprinting polymerization using magnetic multi-walled carbon nanotubes as the support material, cinnamic acid as the template and dopamine as the functional monomer. The magnetic imprinted polymers were characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The results revealed that the magnetic imprinted polymers had outstanding magnetic properties, high adsorption capacity, selectivity and fast kinetic binding toward cinnamic acid, ferulic acid and caffeic acid. Coupled with high-performance liquid chromatography, the extraction conditions of the magnetic imprinted polymers as a magnetic solid-phase extraction sorbent were investigated in detail. The proposed imprinted magnetic solid phase extraction procedure has been used for the purification and enrichment of cinnamic acid, ferulic acid and caffeic acid successfully from radix scrophulariae extraction sample with recoveries of 92.4-115.0% for cinnamic acid, 89.4-103.0% for ferulic acid and 86.6-96.0% for caffeic acid.

  16. What Variables Affect Solubility?

    ERIC Educational Resources Information Center

    Baker, William P.; Leyva, Kathryn

    2003-01-01

    Helps middle school students understand the concept of solubility through hands-on experience with a variety of liquids and solids. As they explore factors that affect solubility and saturation, students gain content mastery and an understanding of the inquiry process. Also enables teachers to authentically assess student performance on several…

  17. Influence of solid-state acidity on the decomposition of sucrose in amorphous systems. I.

    PubMed

    Alkhamis, Khouloud A

    2008-10-01

    It was of interest to develop a method for solid-state acidity measurements using pH indicators and to correlate this method to the degradation rate of sucrose. Amorphous samples containing lactose 100mg/ml, sucrose 10mg/ml, citrate buffer (1-50mM) and sodium chloride (to adjust the ionic strength) were prepared by freeze-drying. The lyophiles were characterized using powder X-ray diffraction, differential scanning calorimetry and Karl Fischer titremetry. The solid-state acidity of all lyophiles was measured using diffuse reflectance spectroscopy and suitable indicators (thymol blue or bromophenol blue). The prepared lyophiles were subjected to a temperature of 60 degrees C and were analyzed for degradation using the Trinder kit. The results obtained from this study have shown that the solid-state acidity depends mainly on the molar ratio of the salt and the acid used in buffer preparation and not on the initial pH of the solution. The degradation of sucrose in the lyophiles is extremely sensitive to the solid-state acidity and the ionic strength. Reasonable correlation was obtained between the Hammett acidity function and sucrose degradation rate. The use of cosolvents (in the calibration plots) can provide good correlations with the rate of an acid-catalyzed reaction, sucrose inversion, in amorphous lyophiles. PMID:18647642

  18. Redox potentials and kinetics of the Ce 3+/Ce 4+ redox reaction and solubility of cerium sulfates in sulfuric acid solutions

    NASA Astrophysics Data System (ADS)

    Paulenova, A.; Creager, S. E.; Navratil, J. D.; Wei, Y.

    Experimental work was performed with the aim of evaluating the Ce 4+/Ce 3+ redox couple in sulfuric acid electrolyte for use in redox flow battery (RFB) technology. The solubility of cerium sulfates in 0.1-4.0 M sulfuric acid at 20-60 °C was studied. A synergistic effect of both sulfuric acid concentration and temperature on the solubility of cerous sulfate was observed. The solubility of cerous sulfate significantly decreased with rising concentration of sulfuric acid and rising temperature, while the solubility of ceric sulfate goes through a significant maximum at 40 °C. Redox potentials and the kinetics of the cerous/ceric redox reaction were also studied under the same temperature-concentration conditions. The redox potentials were measured using the combined redox electrode (Pt-Ag/AgCl) in equimolar Ce 4+/Ce 3+ solutions (i.e.[Ce 3+]=[Ce 4+]) in sulfuric acid electrolyte. The Ce 3+/Ce 4+ redox potentials significantly decrease (i.e. shift to more negative values) with rising sulfuric acid concentration; a small maximum is observed at 40 °C. Cyclic voltammetric experiments confirmed slow electrochemical kinetics of the Ce 3+/Ce 4+ redox reaction on carbon glassy electrodes (CGEs) in sulfuric acid solutions. The observed dependencies of solubilities, the redox potentials and the kinetics of Ce 3+/Ce 4+ redox reaction on sulfuric acid concentration are thought to be the result of inequivalent complexation of the two redox species by sulfate anions: the ceric ion is much more strongly bound to sulfate than is the cerous ion. The best temperature-concentration conditions for the RFB electrolytes appear to be 40 °C and 1 M sulfuric acid, where the relatively good solubility of both cerium species, the maximum of redox potentials, and the more or less satisfying stability of CGE s were found. Even so, the relatively low solubility of cerium salts in sulfuric acid media and slow redox kinetics of the Ce 3+/Ce 4+ redox reaction at carbon indicate that the Ce 3+/Ce

  19. n-hydrocarbons conversions over metal-modified solid acid catalysts

    NASA Astrophysics Data System (ADS)

    Zarubica, A.; Ranđelović, M.; Momčilović, M.; Radulović, N.; Putanov, P.

    2013-12-01

    The quality of a straight-run fuel oil can be improved if saturated n-hydrocarbons of low octane number are converted to their branched counterparts. Poor reactivity of traditional catalysts in isomerization reactions imposed the need for the development of new catalysts among which noble metal promoted acid catalysts, liquid and/or solid acid catalysts take a prominent place. Sulfated zirconia and metal promoted sulfated zirconia exhibit high activity for the isomerization of light alkanes at low temperatures. The present paper highlights the original results which indicate that the modification of sulfated zirconia by incorporation of metals (platinum and rhenium) significantly affects catalytic performances in n-hydrocarbon conversion reactions. Favourable activity/selectivity of the promoted sulfated zirconia depends on the crystal phase composition, critical crystallites sizes, platinum dispersion, total acidity and type of acidity. Attention is also paid to the recently developed solid acid catalysts used in other conversion reactions of hydrocarbons.

  20. Thermodynamics of aragonite-strontianite solid solutions: Results from stoichiometric solubility at 25 and 76°C

    USGS Publications Warehouse

    Plummer, L.N.; Busenberg, E.

    1987-01-01

    Neither equilibrium nor stoichiometric saturation is observed at 76°C during laboratory recrystallization of strontianite-aragonite solid solutions even after apparent 100 percent conversion to a narrow secondary composition and demonstration of a nearly constant composition system for periods of 300 hours.

  1. Effect of initial total solids concentration on volatile fatty acid production from food waste during anaerobic acidification.

    PubMed

    Wang, Quan; Jiang, Jianguo; Zhang, Yujing; Li, Kaimin

    2015-01-01

    The effect of initial total solids (TS) concentration on volatile fatty acid (VFAs) production from food waste under mesophilic conditions (35 °C) was determined. VFAs concentration and composition, biogas production, soluble chemical oxygen demand concentration, TS and volatile solids (VS) reduction, and ammonia nitrogen [Formula: see text] release were investigated. The VFAs concentrations were 26.10, 39.68, 59.58, and 62.64 g COD/L at TS contents of 40, 70, 100, and 130 g/L, respectively. While the VFAs' yields ranged from 0.467 to 0.799 g COD/g VSfed, decreased as initial TS increased. The percentage of propionate was not affected by TS concentration, accounting for 30.19-34.86% of the total VFAs, while a higher percentage of butyrate and lower percentage of acetate was achieved at a higher TS concentration. Biogas included mainly hydrogen and carbon dioxide and the maximum hydrogen yield of 148.9 ml/g VSfed was obtained at 130 g TS/L. [Formula: see text] concentration, TS and VS reductions increased as initial TS increased. Considering the above variables, we conclude that initial TS of 100 g/L shall be the most appropriate to VFAs production.

  2. Extended utility of molten-salt chemistry: unprecedented synthesis of a water-soluble salt-inclusion solid comprised of high-nuclearity vanadium oxide clusters.

    PubMed

    Queen, Wendy L; West, J Palmer; Hudson, Joan; Hwu, Shiou-Jyh

    2011-11-01

    Polyoxometallates (POMs) are desirable in materials applications ranging from uses as catalysts in selective oxidation reactions to molecular-like building blocks for the preparation of new extended solids. With the use of an unprecedented approach involving high temperature, molten salt methods, a fascinating series of salt-inclusion solids (SISs) that contain high nuclearity POMs has been isolated for the first time. Cs(11)Na(3)(V(15)O(36))Cl(6) (1) was synthesized using the eutectic NaCl/CsCl flux (mp 493 °C) which serves as a reactive solvent in crystal growth and allows for the SIS formation. Its framework can be viewed as an "ionic" lattice composed of alternately packed counterions of Cl-centered [V(15)O(36)Cl](9-) clusters (V15; S = 11/2) and multinuclear [Cs(9)Na(3)Cl(5)](7+) cations. In light of the structural analysis, 1 was proven to be soluble in water giving rise to a dark green solution that is similar in color to single crystals of the title compound. Infrared spectroscopy of the solid formed from fast evaporation of the solution supports the presence of dissolved V15 clusters. Also noteworthy is the magnetization of 1 at 2 K, which reveals an s-shaped plot resembling that of superparamagnetic materials.

  3. Incorporation of Mg and Ca into nanostructured Fe2O3 improves Fe solubility in dilute acid and sensory characteristics in foods.

    PubMed

    Hilty, Florentine M; Knijnenburg, Jesper T N; Teleki, Alexandra; Krumeich, Frank; Hurrell, Richard F; Pratsinis, Sotiris E; Zimmermann, Michael B

    2011-01-01

    Iron deficiency is one of the most common micronutrient deficiencies worldwide. Food fortification can be an effective and sustainable strategy to reduce Fe deficiency but selection of iron fortificants remains a challenge. Water-soluble compounds, for example, FeSO(4), usually demonstrate high bioavailability but they often cause unacceptable sensory changes in foods. On the other hand, poorly acid-soluble Fe compounds, for example FePO(4), may cause fewer adverse sensory changes in foods but are usually not well bioavailable since they need to be dissolved in the stomach prior to absorption. The solubility and the bioavailability of poorly acid-soluble Fe compounds can be improved by decreasing their primary particle size and thereby increasing their specific surface area. Here, Fe oxide-based nanostructured compounds with added Mg or Ca were produced by scalable flame aerosol technology. The compounds were characterized by nitrogen adsorption, X-ray diffraction, transmission electron microscopy, and Fe solubility in dilute acid. Sensory properties of the Fe-based compounds were tested in 2 highly reactive, polyphenol-rich food matrices: chocolate milk and fruit yoghurt. The Fe solubility of nanostructured Fe(2)O(3) doped with Mg or Ca was higher than that of pure Fe(2)O(3). Since good solubility in dilute acid was obtained despite the inhomogeneity of the powders, inexpensive precursors, for example Fe- and Ca-nitrates, can be used for their manufacture. Adding Mg or Ca lightened powder color, while sensory changes when added to foods were less pronounced than for FeSO(4). The combination of high Fe solubility and low reactivity in foods makes these flame-made nanostructured compounds promising for food fortification. Practical Application: The nanostructured iron-containing compounds presented here may prove useful for iron fortification of certain foods; they are highly soluble in dilute acid and likely to be well absorbed in the gut but cause less severe

  4. Water-soluble complexes of star-shaped poly(acrylic acid) with quaternized poly(4-vinylpyridine).

    PubMed

    Pergushov, Dmitry V; Babin, Ivan A; Plamper, Felix A; Zezin, Alexander B; Müller, Axel H E

    2008-06-01

    The interaction of star-shaped poly(acrylic acid) having various numbers of arms (5, 8, and 21) and a strong cationic polyelectrolyte, viz., poly( N-ethyl-4-vinylpyridinium bromide), was examined at pH 7 by means of turbidimetry and dynamic light scattering. Mixing aqueous solutions of the oppositely charged polymeric components was found to result in phase separation only if their base-molar ratio Z = [N+]/[COO (-) + COOH] exceeds a certain critical value ZM ( ZM < 1); this threshold value is determined by the number of arms of the star-shaped polyelectrolyte and the ionic strength of the surrounding solution. At Z < ZM, the homogeneous aqueous mixtures of the oppositely charged polymeric components contain two types of complex species clearly differing in their sizes, with the fractions of these species appearing to depend distinctly on the number of arms of the star-shaped poly(acrylic acid), the base-molar ratio of the oppositely charged polymeric components in their mixtures, and the ionic strength of the surrounding solution. The small complex species (major fraction) are assumed to represent the particles of the water-soluble interpolyelectrolyte complex whereas the large complex species (minor fraction) are considered to be complex aggregates.

  5. The Use of Functional Nucleic Acids in Solid-Phase Fluorimetric Assays

    NASA Astrophysics Data System (ADS)

    Rupcich, Nicholas; Nutiu, Razvan; Shen, Yutu; Li, Yingfu; Brennan, John D.

    The past 15 years have seen a revolution in the area of functional nucleic acid (FNA) research since the demonstration that single-stranded RNA and DNA species can be used for both ligand binding and catalysis. An emerging area of application for such species is in the development of solid-phase fluorimetric assays for biosensing, proteomics, and drug screening purposes. In this chapter, the methods for immobilization of functional nucleic acids are briefly reviewed, with emphasis on emerging technologies such as sol-gel encapsulation. Methods for generating fluorescence signals from aptamers and nucleic acid enzymes are then described, and the use of such species in solid-phase fluorimetric assays is then discussed. Unique features of sol-gel based materials for the development of solid-phase assays are highlighted, and some emerging applications of immobilized FNA species are discussed.

  6. Release of Water Soluble Drugs from Dynamically Swelling POLY(2-HYDROXYETHYL Methacrylate - CO - Methacrylic Acid) Hydrogels.

    NASA Astrophysics Data System (ADS)

    Kou, Jim Hwai-Cher

    In this study, ionizable copolymers of HEMA and methacrylic acid (MA) are investigated for their potential use in developing pH dependent oral delivery systems. Because of the MA units, these gels swell extensively at high pH. Since solute diffusion in the hydrophilic polymers depends highly on the water content of the matrix, it is anticipated that the release rate will be modulated by this pH induced swelling. From a practical point of view, the advantage of the present system is that one can minimize drug loss in the stomach and achieve a programmed release in intestine. This approach is expected to improve delivery of acid labile drugs or drugs that cause severe gastrointestinal side effects. This work mainly focuses on the basic understanding of the mechanism involved in drug release from the poly(HEMA -co- MA) gels, especially under dynamic swelling conditions. Equilibrium swelling is first characterized since water content is the major determinant of transport properties in these gels. Phenylpropanolamine (PPA) is chosen as the model drug for the release study and its diffusion characteristics in the gel matrix determined. The data obtained show that the PPA diffusivity follows the free volume theory of Yasuda, which explains the accelerating effect of swelling on drug release. A mathematical model based on a diffusion mechanism has been developed to describe PPA release from the swelling gels. Based on this model, several significant conclusions can be drawn. First, the release rate can be modulated by the aspect ratio of the cylindrical geometry, and this has a practical implication in dosage form design. Second, the release rate can be lowered quite considerably if the dimensional increase due to swelling is significant. Consequently, it is the balance between the drug diffusivity increase and the gel dimensional growth that determines the release rate from the swelling matrix. Third, quasi-steady release kinetics, which are characteristic of swelling

  7. Solubilities and Glass Formation in Aqueous Solutions of the Sodium Salts of Malonic Acid With and Without Ammonium Sulfate.

    PubMed

    Kissinger, Jared A; Buttke, Lukas G; Vinokur, Anastasiya I; Guzei, Ilia A; Beyer, Keith D

    2016-06-01

    The solubility of sodium hydrogen malonate and sodium malonate in water both with and without ammonium sulfate present has been studied using differential scanning calorimetry and infrared spectroscopy. The crystals that form from sodium hydrogen malonate/water solutions were determined to be sodium hydrogen malonate monohydrate by single-crystal X-ray diffractometry. The crystals formed in sodium malonate/water solutions were determined to be sodium malonate monohydrate, a compound whose structure had not been previously known. When ammonium sulfate is added to these respective aqueous systems, the precipitation solids contain sodium sulfate decahydrate under low to moderate ammonium concentrations and lecontite (NaNH4SO4·2H2O) under high ammonium concentrations, which can be found under dry atmospheric conditions. Thus, it appears the presence of malonate and hydrogen malonate ions does not significantly affect the precipitation of inorganic salts in these systems. The glass transition temperatures of all solutions were also determined, and it was observed that the addition of ammonium sulfate slightly lowers the glass transition temperature in these solutions.

  8. Rational Design of a Colorimetric pH Sensor from a Soluble Retinoic Acid Chaperone

    PubMed Central

    Berbasova, Tetyana; Nosrati, Meisam; Vasileiou, Chrysoula; Wang, Wenjing; Lee, Kin Sing Stephen; Yapici, Ipek; Geiger, James H.; Borhan, Babak

    2014-01-01

    Reengineering of cellular retinoic acid binding protein II (CRABPII) to be capable of binding retinal as a protonated Schiff base is described. Through rational alterations of the binding pocket, electrostatic perturbations of the embedded retinylidene chromophore that favor delocalization of the iminium charge lead to exquisite control in the regulation of chromophoric absorption properties, spanning the visible spectrum (474–640 nm). The pKa of the retinylidene protonated Schiff base was modulated from 2.4 to 8.1, giving rise to a set of proteins of varying colors and pH sensitivities. These proteins were used to demonstrate a concentration-independent, ratiometric pH sensor. PMID:24059243

  9. Rational design of a colorimetric pH sensor from a soluble retinoic acid chaperone.

    PubMed

    Berbasova, Tetyana; Nosrati, Meisam; Vasileiou, Chrysoula; Wang, Wenjing; Lee, Kin Sing Stephen; Yapici, Ipek; Geiger, James H; Borhan, Babak

    2013-10-30

    Reengineering of cellular retinoic acid binding protein II (CRABPII) to be capable of binding retinal as a protonated Schiff base is described. Through rational alterations of the binding pocket, electrostatic perturbations of the embedded retinylidene chromophore that favor delocalization of the iminium charge lead to exquisite control in the regulation of chromophoric absorption properties, spanning the visible spectrum (474-640 nm). The pKa of the retinylidene protonated Schiff base was modulated from 2.4 to 8.1, giving rise to a set of proteins of varying colors and pH sensitivities. These proteins were used to demonstrate a concentration-independent, ratiometric pH sensor. PMID:24059243

  10. Chemical modeling of acid-base properties of soluble biopolymers derived from municipal waste treatment materials.

    PubMed

    Tabasso, Silvia; Berto, Silvia; Rosato, Roberta; Marinos, Janeth Alicia Tafur; Ginepro, Marco; Zelano, Vincenzo; Daniele, Pier Giuseppe; Montoneri, Enzo

    2015-02-04

    This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials.

  11. DNA detection using water-soluble conjugated polymers and peptide nucleic acid probes

    NASA Astrophysics Data System (ADS)

    Gaylord, Brent S.; Heeger, Alan J.; Bazan, Guillermo C.

    2002-08-01

    The light-harvesting properties of cationic conjugated polymers are used to sensitize the emission of a dye on a specific peptide nucleic acid (PNA) sequence for the purpose of homogeneous, "real-time" DNA detection. Signal transduction is controlled by hybridization of the neutral PNA probe and the negative DNA target. Electrostatic interactions bring the hybrid complex and cationic polymer within distances required for Förster energy transfer. Conjugated polymer excitation provides fluorescein emission >25 times higher than that obtained by exciting the dye, allowing detection of target DNA at concentrations of 10 pM with a standard fluorometer. A simple and highly sensitive assay with optical amplification that uses the improved hybridization behavior of PNA/DNA complexes is thus demonstrated.

  12. Bench-Scale and Pilot-Scale Treatment Technologies for the Removal of Total Dissolved Solids from Coal Mine Water: A Review

    EPA Science Inventory

    Coal mine water (CMW) is typically treated to remove suspended solids, acidity, and soluble metals, but high concentrations of total dissolved solids (TDS) have been reported to impact the environment at several CMW discharge points. Consequently, various states have establishe...

  13. Glycyrrhetinic acid-poly(ethylene glycol)-glycyrrhetinic acid tri-block conjugates based self-assembled micelles for hepatic targeted delivery of poorly water soluble drug.

    PubMed

    Wu, Fengbo; Xu, Ting; Liu, Chi; Chen, Can; Song, Xiangrong; Zheng, Yu; He, Gu

    2013-01-01

    The triblock 18β-glycyrrhetinic acid-poly(ethylene glycol)18β-glycyrrhetinic acid conjugates (GA-PEG-GA) based self-assembled micelles were synthesized and characterized by FTIR, NMR, transmission electron microscopy, and particle size analysis. The GA-PEG-GA conjugates having the critical micelle concentration of 6 × 10(-5) M were used to form nanosized micelles, with mean diameters of 159.21 ± 2.2 nm, and then paclitaxel (PTX) was incorporated into GA-PEG-GA micelles by self-assembly method. The physicochemical properties of the PTX loaded GA-PEG-GA micelles were evaluated including in vitro cellular uptake, cytotoxicity, drug release profile, and in vivo tissue distribution. The results demonstrate that the GA-PEG-GA micelles had low cytotoxicity and good ability of selectively delivering drug to hepatic cells in vitro and in vivo by the targeting moiety glycyrrhetinic acid. In conclusion, the GA-PEG-GA conjugates have potential medical applications for targeted delivery of poor soluble drug delivery.

  14. Preparation and characterization of biomass carbon-based solid acid catalyst for the esterification of oleic acid with methanol.

    PubMed

    Liu, Tiantian; Li, Zhilong; Li, Wei; Shi, Congjiao; Wang, Yun

    2013-04-01

    A solid acid catalyst, prepared by sulfonating carbonized corn straw, was proved to be an efficient and environmental benign catalyst for the esterification of oleic acid and methanol. Various synthetic parameters, such as carbonization temperature and time were systematically examined. It was found that the catalyst exhibited the highest acid density of 2.64 mmol/g by NaOH titration. A quantitative yield (98%) of ester was achieved, using the most active sulfonated catalyst at 333 K with a 7 wt.% catalyst/oleic acid ratio for 4h, at a 7:1 M ratio of methanol/oleic acid, while the commercial available Amberlyst-15 only gave 85% yield under the same reaction condition.

  15. [Preparation of two poor water soluble drugs - nanoporous ZnO solid dispersions and the mechanism of drug dissolution improvement].

    PubMed

    Gao, Bei; Sun, Chang-shan; Zhi, Zhuang-zhi; Wang, Yan; Chang, Di; Wang, Si-ling; Jiang, Tong-ying

    2011-11-01

    Nanoporous ZnO was used as a carrier to prepare drug solid dispersion, the mechanism of which to improve the drug dissolution was also studied. Nanoporous ZnO, obtained through chemical deposition method, was used as a carrier to prepare indomethacin and cilostazol solid dispersions by melt-quenching method, separately. The results of scanning electron microscope, surface area analyzer, fourier transform infra-red spectroscopy, differential scanning calorimeter and X-ray diffraction showed that drugs were implanted into nanopores of ZnO by physical adsorption effect and highly dispersed into nanopores of ZnO in amorphous form, moreover, these nanopores strongly inhibited amorphous recrystallization in the condition of 45 degrees C and 75% RH. In addition, the results of the dissolution tested in vitro exhibited that the accumulated dissolutions of indomethacin and cilostazol solid dispersions achieved about 90% within 5 min and approximately 80% within 30 min. It was indicated in this study that the mechanism of drug dissolution improvement was associated with the effects of nanoporous ZnO carrier on increasing drug dispersion, controlling drug in nanopores as amorphous form and inhibiting amorphous recrystallization. PMID:22260037

  16. Dissolution-enhancing mechanism of alkalizers in poloxamer-based solid dispersions and physical mixtures containing poorly water-soluble valsartan.

    PubMed

    Ha, Nam Sung; Tran, Thao Truong-Dinh; Tran, Phuong Ha-Lien; Park, Jun-Bom; Lee, Beom-Jin

    2011-01-01

    The purpose of this study was to investigate the effects of alkalizers in dissolution rate and crystal structure of valsartan (VAL) in Poloxamer 407 (POX)-based solid dispersions (SD). VAL, a poorly-water soluble drug was selected as a model drug because of its low solubility at low pH. The POX-based SDs containing alkalizers (Na₂CO₃, MgO, meglumine and arginine) were prepared by melting method. The dissolution tests were performed using the United States Pharmacopeia (USP) paddle II method in enzyme-free simulated gastric fluid (pH 1.2) for 2 h. Microenvironmental pH (pH(M)) was examined potentiometrically by using a surface pH electrode. Dissolution rate of SD incorporating Na₂CO₃ was drastically increased. The differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) data indicated that crystalline structure of VAL in SD was transformed to amorphous form by the addition of alkalizers but could not explain the differences in the dissolution rates. The molecular interaction between VAL and Na₂CO₃ was observed in the Fourier transform infrared spectroscopy (FT-IR) spectra by the shift of C=O band from 1732 to 1719 cm⁻¹ and the disappearance of carbonyl group at 1598 cm⁻¹. Furthermore, Na₂CO₃ efficiently modulated pH(M) by providing a favorable microenvironment for drug dissolution. A combination of SD method and use of alkalizer is a promising approach to modulate release rate of poorly water-soluble and ionizable drug with an aid of changes of drug crystallinity, molecular interaction and pH(M).

  17. Single Benzene Green Fluorophore: Solid-State Emissive, Water-Soluble, and Solvent- and pH-Independent Fluorescence with Large Stokes Shifts.

    PubMed

    Beppu, Teruo; Tomiguchi, Kosuke; Masuhara, Akito; Pu, Yong-Jin; Katagiri, Hiroshi

    2015-06-15

    Benzene is the simplest aromatic hydrocarbon with a six-membered ring. It is one of the most basic structural units for the construction of π conjugated systems, which are widely used as fluorescent dyes and other luminescent materials for imaging applications and displays because of their enhanced spectroscopic signal. Presented herein is 2,5-bis(methylsulfonyl)-1,4-diaminobenzene as a novel architecture for green fluorophores, established based on an effective push-pull system supported by intramolecular hydrogen bonding. This compound demonstrates high fluorescence emission and photostability and is solid-state emissive, water-soluble, and solvent- and pH-independent with quantum yields of Φ=0.67 and Stokes shift of 140 nm (in water). This architecture is a significant departure from conventional extended π-conjugated systems based on a flat and rigid molecular design and provides a minimum requirement for green fluorophores comprising a single benzene ring.

  18. Highly water-soluble monoboronic acid probes that show optical sensitivity to glucose based on 4-sulfo-1,8-naphthalic anhydride.

    PubMed

    Cao, Zhi; Nandhikonda, Premchendar; Heagy, Michael D

    2009-05-01

    Two highly water-soluble monoboronic acid probes that display the more desirable off-on fluorescence response were synthesized based on 4-sulfo-1,8-naphthalic anhydride and a remarkable sensitivity for glucose rather than fructose and galactose was also observed.

  19. Species specific identification of spore-producing microbes using the gene sequence of small acid-soluble spore coat proteins for amplification based diagnostics

    SciTech Connect

    McKinney, Nancy

    2002-01-01

    PCR (polymerase chain reaction) primers for the detection of certain Bacillus species, such as Bacillus anthracis. The primers specifically amplify only DNA found in the target species and can distinguish closely related species. Species-specific PCR primers for Bacillus anthracis, Bacillus globigii and Clostridium perfringens are disclosed. The primers are directed to unique sequences within sasp (small acid soluble protein) genes.

  20. HOBr in sulfuric acid solutions: Solubility and reaction with HCl as a function of temperature and concentration

    SciTech Connect

    Waschewsky, G.C.G.; Abbatt, J.P.D.

    1999-07-08

    Although the total atmospheric loading of inorganic bromine is relatively low, not exceeding a few tens of parts per trillion, there has been considerable interest in recent years in the heterogeneous interactions which brominated species undergo in the atmosphere. A detailed study of the interaction of HOBr and HCl in cold sulfuric acid solutions has been performed using a coated-wall flow tube coupled to an electron-impact mass spectrometer. The liquid-phase bimolecular rate constants, measured over a temperature range from 213 to 238 K and in solutions from 59.7 to 70.1 wt % composition, show a strong positive dependence on both acid composition and temperature. The solubility of HOBr has also been measured in these solutions by analyzing its time-dependent uptake. Henry`s Law constants (H) determined from the measured values of HD{sup 1/2} and the liquid-phase diffusion coefficient (D) are independent of acid composition over the above range of solution compositions. The values of H demonstrate a clear Clausius-Clapeyron temperature dependence, with a heat of solution of {minus}9 {+-} 1 kcal/mol. When the atmospheric importance of these data is assessed, two conclusions are reached. In the stratosphere, under aerosol conditions observed soon after the Mt. Pinatubo volcano eruption, the rates of HCl activation via the HOBr/HCl heterogeneous reaction are comparable with the rate of activation via gas-phase reaction with OH at relatively warm temperatures (205--220 K), where other HCl-activating heterogeneous reactions occur slowly. In the high Arctic boundary layer, it is possible that significant HCl activation could occur when elevated levels of photochemically active bromine are present.

  1. [Near-infrared spectra combining with CARS and SPA algorithms to screen the variables and samples for quantitatively determining the soluble solids content in strawberry].

    PubMed

    Li, Jiang-bo; Guo, Zhi-ming; Huang, Wen-qian; Zhang, Bao-hua; Zhao, Chun-jiang

    2015-02-01

    In using spectroscopy to quantitatively or qualitatively analyze the quality of fruit, how to obtain a simple and effective correction model is very critical for the application and maintenance of the developed model. Strawberry as the research object, this research mainly focused on selecting the key variables and characteristic samples for quantitatively determining the soluble solids content. Competitive adaptive reweighted sampling (CARS) algorithm was firstly proposed to select the spectra variables. Then, Samples of correction set were selected by successive projections algorithm (SPA), and 98 characteristic samples were obtained. Next, based on the selected variables and characteristic samples, the second variable selection was performed by using SPA method. 25 key variables were obtained. In order to verify the performance of the proposed CARS algorithm, variable selection algorithms including Monte Carlo-uninformative variable elimination (MC-UVE) and SPA were used as the comparison algorithms. Results showed that CARS algorithm could eliminate uninformative variables and remove the collinearity information at the same time. Similarly, in order to assess the performance of the proposed SPA algorithm for selecting the characteristic samples, SPA algorithm was compared with classical Kennard-Stone algorithm Results showed that SPA algorithm could be used for selection of the characteristic samples in the calibration set. Finally, PLS and MLR model for quantitatively predicting the SSC (soluble solids content) in the strawberry were proposed based on the variables/samples subset (25/98), respectively. Results show that models built by using the 0.59% and 65.33% information of original variables and samples could obtain better performance than using the ones obtained by using all information of the original variables and samples. MLR model was the best with R(pre)2 = 0.9097, RMSEP=0.3484 and RPD = 3.3278.

  2. Solid-State Forms of β-Resorcylic Acid: How Exhaustive Should a Polymorph Screen Be?

    PubMed Central

    2010-01-01

    A combined experimental and computational study was undertaken to establish the solid-state forms of β-resorcylic acid (2,4-dihydroxybenzoic acid). The experimental search resulted in nine crystalline forms: two concomitantly crystallizing polymorphs, five novel solvates (with acetic acid, dimethyl sulfoxide, 1,4-dioxane, and two with N,N-dimethyl formamide), in addition to the known hemihydrate and a new monohydrate. Form II°, the thermodynamically stable polymorph at room temperature, was found to be the dominant crystallization product. A new, enantiotropically related polymorph (form I) was obtained by desolvation of certain solvates, sublimation experiments, and via a thermally induced solid−solid transformation of form II° above 150 °C. To establish their structural features, interconversions, and relative stability, all solid-state forms were characterized with thermal, spectroscopic, X-ray crystallographic methods, and moisture-sorption analysis. The hemihydrate is very stable, while the five solvates and the monohydrate are rather unstable phases that occur as crystallization intermediates. Complementary computational work confirmed that the two experimentally observed β-resorcylic acid forms I and II° are the most probable polymorphs and supported the experimental evidence for form I being disordered in the p-OH proton position. These consistent outcomes suggest that the most practically important features of β-resorcylic acid crystallization under ambient conditions have been established; however, it appears impractical to guarantee that no additional metastable solid-state form could be found. PMID:21218174

  3. The effects of conjugated linoleic acid on growth performance, carcass traits, meat quality, antioxidant capacity, and fatty acid composition of broilers fed corn dried distillers grains with solubles.

    PubMed

    Jiang, Wen; Nie, Shaoping; Qu, Zhe; Bi, Chongpeng; Shan, Anshan

    2014-05-01

    This study investigated the effects of dietary supplementation with conjugated linoleic acid (CLA) on the growth performance, carcass traits, meat quality, antioxidant capacity, and fatty acid composition of broilers fed corn dried distillers grains with solubles (DDGS). Four hundred eighty 1-d-old broilers were randomly assigned to 4 groups, consisting of 6 replicates with 20 broilers each. Broilers were allocated 1 of 4 diets and fed for 49 d in a 2 × 2 factorial design. The dietary treatments consisted of 2 levels of DDGS (0 or 15%) and 2 levels of CLA (0 or 1%). The results of growth performance analyses showed that dietary supplementation with 1% CLA, 15% DDGS, or both in broilers had no significant effects on ADG, ADFI, and feed/gain (P > 0.05). Dietary supplementation with 15% DDGS did not significantly affect meat color values, drip loss percentage, pH value at 15 min, crude fat content, or shear force value (P > 0.05). Diets supplemented with 15% DDGS decreased the proportions of saturated fatty acids (P < 0.05) and monounsaturated fatty acids but increased the proportion of polyunsaturated fatty acids of the thigh meat (P < 0.05). Diets supplemented with 1% CLA significantly decreased the abdominal fat percentage (P < 0.05). Supplementation with 1% CLA increased the crude fat content and decreased the color (b*) value and shear force value of the breast meat (P < 0.05). Diets supplemented with 1% CLA increased the total superoxide dismutase activity of the serum, breast meat, and liver, and decreased the malondialdehyde content of the serum and breast meat (P < 0.05). Supplementation with 1% CLA decreased the proportion of monounsaturated fatty acids and increased the proportion of saturated fatty acids (P < 0.05). Accumulation of CLA in the thigh meat was significantly increased (P < 0.05) with increasing CLA level in the diet. In conclusion, dietary supplementation with 1% CLA had positive effects on meat quality, antioxidant capacity, and fatty acid

  4. Chemical Modeling of Acid-Base Properties of Soluble Biopolymers Derived from Municipal Waste Treatment Materials

    PubMed Central

    Tabasso, Silvia; Berto, Silvia; Rosato, Roberta; Tafur Marinos, Janeth Alicia; Ginepro, Marco; Zelano, Vincenzo; Daniele, Pier Giuseppe; Montoneri, Enzo

    2015-01-01

    This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials. PMID:25658795

  5. Chemical modeling of acid-base properties of soluble biopolymers derived from municipal waste treatment materials.

    PubMed

    Tabasso, Silvia; Berto, Silvia; Rosato, Roberta; Marinos, Janeth Alicia Tafur; Ginepro, Marco; Zelano, Vincenzo; Daniele, Pier Giuseppe; Montoneri, Enzo

    2015-01-01

    This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials. PMID:25658795

  6. Effervescence Assisted Fusion Technique to Enhance the Solubility of Drugs.

    PubMed

    Alam, Mohd Aftab; Al-Jenoobi, Fahad I; Al-Mohizea, Abdullah M; Ali, Raisuddin

    2015-12-01

    The solubility of five poorly soluble drugs was enhanced by using an effervescence assisted solid dispersion (EASD) technique. EASDs were prepared by using modified fusion method. Drug and hydrophilic carrier were melted, and in this molten mixture, effervescence was generated by adding effervescence couple comprising organic acid (citric acid) and carbonic base (sodium bicarbonate). Solubility of drug powders, solid dispersions, and EASDs was determined at 25°C using shake flask method. Atorvastatin calcium, cefuroxime axetil, clotrimazole, ketoconazole, and metronidazole benzoate were estimated using a spectrophotometer at 246, 280, 260, 230, and 232 nm (λ max), respectively. Solubility of atorvastatin calcium (from 100 to 345 μg/ml), cefuroxime axetil (from 441 to 1948 μg/ml), clotrimazole (from 63 to 677 μg/ml), ketoconazole (from 16 to 500 μg/ml), and metronidazole benzoate (from 112 to 208 μg/ml) in EASDs was enhanced by 3.45-, 4.4-, 10.7-, 31.2-, and 1.8-fold, respectively. Scanning electron micrographs of drug powder, solid dispersion, and EASDs were compared. Scanning electron micrographs of EASDs showed a uniform distribution of drug particles in the carrier matrix. Morphology (size and shape) of cefuroxime axetil particles was altered in solid dispersion as well as in EASD. EASDs showed better solubility enhancement than conventional solid dispersions. The present technique is better suitable for drugs having a low melting point or melt without charring. Effervescence assisted fusion technique of preparing solid dispersions can be employed for enhancing solubility, dissolution, and bioavailability of poorly soluble drugs.

  7. Role of solid acid catalysts in bio diesel production.

    PubMed

    Shivayogimath, C B; Sunita, G; Manoj Kumar, B

    2009-07-01

    Biodiesel is gaining importance as an alternate source of attractive fuel because of depleting fossil fuel resources. It is produced by trans-esterification, in which oil or fat reacts with a monohydric alcohol in presence of a catalyst. In the present work, trans-esterification of sunflower oil with methanol is carried out by using zirconia supported isopoly and heteropoly tungstates (HPAs) as catalysts. Effects of reaction parameters, such as catalyst types and its concentration, molar ratio of sunflower oil to methanol, reaction temperature and time, have been optimized to get higher conversion of sunflower oil and the product distribution of fatty acid methyl esters (FAME) in the trans-esterfication reaction.

  8. Formation routes of interstellar glycine involving carboxylic acids: possible favoritism between gas and solid phase.

    PubMed

    Pilling, Sergio; Baptista, Leonardo; Boechat-Roberty, Heloisa M; Andrade, Diana P P

    2011-11-01

    Despite the extensive search for glycine (NH₂CH₂COOH) and other amino acids in molecular clouds associated with star-forming regions, only upper limits have been derived from radio observations. Nevertheless, two of glycine's precursors, formic acid and acetic acid, have been abundantly detected. Although both precursors may lead to glycine formation, the efficiency of reaction depends on their abundance and survival in the presence of a radiation field. These facts could promote some favoritism in the reaction pathways in the gas phase and solid phase (ice). Glycine and these two simplest carboxylic acids are found in many meteorites. Recently, glycine was also observed in cometary samples returned by the Stardust space probe. The goal of this work was to perform theoretical calculations for several interstellar reactions involving the simplest carboxylic acids as well as the carboxyl radical (COOH) in both gas and solid (ice) phase to understand which reactions could be the most favorable to produce glycine in interstellar regions fully illuminated by soft X-rays and UV, such as star-forming regions. The calculations were performed at four different levels for the gas phase (B3LYP/6-31G*, B3LYP/6-31++G**, MP2/6-31G*, and MP2/6-31++G**) and at MP2/6-31++G** level for the solid phase (ice). The current two-body reactions (thermochemical calculation) were combined with previous experimental data on the photodissociation of carboxylic acids to promote possible favoritism for glycine formation in the scenario involving formic and acetic acid in both gas and solid phase. Given that formic acid is destroyed more in the gas phase by soft X-rays than acetic acid is, we suggest that in the gas phase the most favorable reactions are acetic acid with NH or NH₂OH. Another possible reaction involves NH₂CH₂ and COOH, one of the most-produced radicals from the photodissociation of acetic acid. In the solid phase, we suggest that the reactions of formic acid with NH

  9. A new synthetic methodology for the preparation of biocompatible and organo-soluble barbituric- and thiobarbituric acid based chitosan derivatives for biomedical applications.

    PubMed

    Shahzad, Sohail; Shahzadi, Lubna; Mahmood, Nasir; Siddiqi, Saadat Anwar; Rauf, Abdul; Manzoor, Faisal; Chaudhry, Aqif Anwar; Rehman, Ihtesham Ur; Yar, Muhammad

    2016-09-01

    Chitosan's poor solubility especially in organic solvents limits its use with other organo-soluble polymers; however such combinations are highly required to tailor their properties for specific biomedical applications. This paper describes the development of a new synthetic methodology for the synthesis of organo-soluble chitosan derivatives. These derivatives were synthesized from chitosan (CS), triethyl orthoformate and barbituric or thiobarbituric acid in the presence of 2-butannol. The chemical interactions and new functional motifs in the synthesized CS derivatives were evaluated by FTIR, DSC/TGA, UV/VIS, XRD and (1)H NMR spectroscopy. A cytotoxicity investigation for these materials was performed by cell culture method using VERO cell line and all the synthesized derivatives were found to be non-toxic. The solubility analysis showed that these derivatives were readily soluble in organic solvents including DMSO and DMF. Their potential to use with organo-soluble commercially available polymers was exploited by electrospinning; the synthesized derivatives in combination with polycaprolactone delivered nanofibrous membranes.

  10. Economic impact of total solids loading on enzymatic hydrolysis of dilute acid pretreated corn stover.

    PubMed

    Humbird, David; Mohagheghi, Ali; Dowe, Nancy; Schell, Daniel J

    2010-01-01

    In process integration studies of the biomass-to-ethanol conversion process, it is necessary to understand how cellulose conversion yields vary as a function of solids and enzyme loading and other key operating variables. The impact of solids loading on enzymatic cellulose hydrolysis of dilute acid pretreated corn stover slurry was determined using an experimental response surface design methodology. From the experimental work, an empirical correlation was obtained that expresses monomeric glucose yield from enzymatic cellulose hydrolysis as a function of solids loading, enzyme loading, and temperature. This correlation was used in a technoeconomic model to study the impact of solids loading on ethanol production economics. The empirical correlation was used to provide a more realistic assessment of process cost by accounting for changes in cellulose conversion yields at different solids and enzyme loadings as well as enzyme cost. As long as enzymatic cellulose conversion drops off at higher total solids loading (due to end-product inhibition or other factors), there is an optimum value for the total solids loading that minimizes the ethanol production cost. The optimum total solids loading shifts to higher values as enzyme cost decreases.

  11. New solid acids in the triple-layer Dion-Jacobson layered perovskite family

    SciTech Connect

    Geselbracht, Margret J.; White, Helen K.; Blaine, Jeanette M.; Diaz, Miranda J.; Hubbs, Jennifer L.; Adelstein, Nicole; Kurzman, Joshua A.

    2011-03-15

    Research highlights: {yields} New triple-layer Dion-Jacobson layered perovskite solid solutions synthesized. {yields} New series of Ta-doped layered perovskite solid acids, HCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10}. {yields} New series of Sr-doped layered perovskite solid acids, HCa{sub 2-x}Sr{sub x}Nb{sub 3}O{sub 10}. {yields} Layered perovskites with highest Ta content are weaker solid acids than HCa{sub 2}Nb{sub 3}O{sub 10}. -- Abstract: Dion-Jacobson type layered perovskites such as A'Ca{sub 2}Nb{sub 3}O{sub 10} (A' = K, Rb, H) have continued to be of great interest due to their compositional variability, rich interlayer chemistry, and wide range of physical properties. In this study, we investigated the range and effects of substitutional doping of Ta{sup 5+} for Nb{sup 5+} and of Sr{sup 2+} for Ca{sup 2+} in A'Ca{sub 2}Nb{sub 3}O{sub 10}. We have prepared and characterized three new solid solutions: KCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10}, RbCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10}, and RbCa{sub 2-x}Sr{sub x}Nb{sub 3}O{sub 10}. These materials all readily undergo proton exchange to form two new series of hydrated solid acid phases, which in most cases can be dehydrated to form stable HCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10} and HCa{sub 2-x}Sr{sub x}Nb{sub 3}O{sub 10} compounds. Intercalation studies with n-hexylamine and pyridine were carried out to gauge the relative Bronsted acidities across the HCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10} series, and we determined that materials with the highest tantalum contents are weaker acids than the parent compound HCa{sub 2}Nb{sub 3}O{sub 10}. Preliminary intercalation studies with pyridine for the HCa{sub 2-x}Sr{sub x}Nb{sub 3}O{sub 10}.yH{sub 2}O solid acids, however, showed no significant difference in acidity with varying strontium content.

  12. Sulfonated mesoporous silica-carbon composites and their use as solid acid catalysts

    NASA Astrophysics Data System (ADS)

    Valle-Vigón, Patricia; Sevilla, Marta; Fuertes, Antonio B.

    2012-11-01

    The synthesis of highly functionalized porous silica-carbon composites made up of sulfonic groups attached to a carbon layer coating the pores of three types of mesostructured silica (i.e. SBA-15, KIT-6 and mesocellular silica) is presented. The synthesis procedure involves the following steps: (a) removal of the surfactant, (b) impregnation of the silica pores with a carbon precursor, (c) carbonization and (d) sulfonation. The resulting silica-carbon composites contain ˜30 wt % of carbonaceous matter with a high density of acidic groups attached to the deposited carbon (i.e.sbnd SO3H, sbnd COOH and sbnd OH). The structural characteristics of the parent silica are retained in the composite materials, which exhibit a high surface area, a large pore volume and a well-ordered porosity made up uniform mesopores. The high density of the sulfonic groups in combination with the mesoporous structure of the composites ensures that a large number of active sites are easily accessible to reactants. These sulfonated silica-carbon composites behave as eco-friendly, active, selective, water tolerant and recyclable solid acids. In this study we demonstrate the usefulness of these composites as solid acid catalysts for the esterification of maleic anhydride, succinic acid and oleic acid with ethanol. These composites exhibit a superior intrinsic catalytic activity to other commercial solid acids such as Amberlyst-15.

  13. Solid solubility in 1:13 phase of doping element for La(Fe,Si)13 alloys

    NASA Astrophysics Data System (ADS)

    Zong, S. T.; Wang, C. L.; Long, Y.; Fu, B.; Shi, J. M.; Han, J.; Zhao, Y. Y.

    2016-05-01

    The influences of Ni, Cr and Nb as substitution elements for Fe were investigated. The change in microstructure and the magnetic properties have been discussed in detail. Substitution elements Ni, Cr and Nb not only have limited solubility in NaZn13-type (1:13) phase, but also hinder the peritectoid reaction. Ni element mainly enters into La-rich phase while Cr element mainly concentrates in α-Fe phase, which both have detriment effect on the peritectoid reaction, leading to a large residual of impurity phases after annealing and a decrease of magnetic entropy change. Besides, Ni and Cr participated in peritectoid reaction by entering parent phases but slightly entering 1:13 phase, which would cause the disappearance of first order magnetic phase transition. A new phase (Fe,Si)2Nb was found when Nb element substitutes Fe in La(Fe,Si)13, suggesting that Nb does not participate in peritectoid reaction and only exists in (Fe,Si)2Nb phase after annealing. The alloy with Nb substitution maintains the first order magnetic phase transition character.

  14. Correlation of biological value of feed phosphates with their solubility in water, dilute hydrogen chloride, dilute citric acid, and neutral ammonium citrate.

    PubMed

    Sullivan, T W; Douglas, J H; Gonzalez, N J; Bond, P L

    1992-12-01

    Relative biological values (BV) of 36 feed phosphates were determined with female turkeys in bioassays of 21-day duration using three response criteria: weight gain, tibia ash percentage, and gain:feed ratio. Calcium phosphate, dibasic dihydrate (United States Pharmacopeia) was the reference standard. Nine mono-dicalcium phosphates (M-DCP, 21.0% phosphorus), 13 di-monocalcium phosphates (D-MCP, 18.5% phosphorus), and 14 defluorinated phosphates (DFP, 18.0% phosphorus) were evaluated. The average relative BV for M-DCP, D-MCP, and DFP samples were 97.6, 94.6, and 90.8%, respectively. Solubility of phosphates was determined by four recognized methods. The solvents were water, .4% HCl, 2.0% citric acid (CA), and neutral ammonium citrate (NAC). Water solubility of M-DCP samples was greater (67.5%) than that of D-MCP (38.8%) and DFP (8.9%) samples. Correlation of water solubility of phosphates to their relative BV was quite low, and water solubility was a poor indicator of BV. When .4% HCl was the solvent, correlation coefficients (r) were .55, .33, and .72 for M-DCP, D-MCP, and DFP, respectively. Based on these results and prediction equations, .4% HCl solubility would be inappropriate for estimating BV of M-DCP and D-MCP samples. Solubility of feed phosphates (mainly D-MCP and DFP) in 2.0% CA or NAC was positively correlated with BV; the r values were .87 to .95. Both of these solubility tests provided a good index of BV. However, it would seem inappropriate and risky to replace bioassays totally with these tests. Feed phosphate users could perform either the 2.0% CA or NAC solubility test easily as a screen for BV along with other quality control procedures (i.e., phosphorus, calcium, sodium, and fluoride determinations).

  15. Directed evolution and structural analysis of N-carbamoyl-D-amino acid amidohydrolase provide insights into recombinant protein solubility in Escherichia coli

    SciTech Connect

    Jiang, Shimin; Li, Chunhong; Zhang, Weiwen; Cai, Yuanheng; Yang, Yunlin; Yang, Sheng; Jiang, Weihong

    2007-03-15

    One of the greatest bottlenecks in producing recombinant proteins in Escherichia coli is that over-expressed target proteins are mostly present in an insoluble form without any biological activity. N-carbamoyl-D-amino-acid amidohydrolase (DCase) is an important enzyme involved in semi-synthesis of β-lactam antibiotics in industry. In this study, in order to determine the amino acid sites responsible for solubility in DCase, error-prone PCR and DNA shuffling techniques are applied to randomly mutate its encoding sequence, followed by an efficient screening based on structural complementation. Several mutants of DCase with reduced aggregation are isolated. Solubility tests of these mutants and several other mutants generated by site-directed mutagenesis indicate that three amino acid residues of DCase (A18, Y30 and K34) are related to the protein solubility in DCase. In silico structural modeling analyses further suggest that hydrophilicity and/or negative charge at these three residues may be responsible for the increased solubility of DCase proteins in E. coli. Based on the information, multiple engineering designated mutants were constructed by site-directed mutagenesis; among them, a triple mutant A18T/Y30N/K34E (named as DCase-M3) can be over-expressed in E. coli with up to 80% of DCase-M3 protein as soluble. DCase-M3 is purified to homogeneity and a comparative analysis with WT DCase demonstrates that DCase-M3 enzyme is similar to the native DCase in terms of its kinetic and thermodynamic properties. The study provides new insights on recombinant protein solubility in E. coli.

  16. Continuous Isosorbide Production From Sorbitol Using Solid Acid Catalysis

    SciTech Connect

    Williamson, R.; Holladay,J.; Jaffe, M.; Brunelle, D.

    2006-09-29

    This is a final report for a project funded by the US Department of Agriculture and managed by the US Department of Energy. The Iowa Corn Promotion Board was the principal contracting entity for the grant. The Iowa Corn Promotion Board subcontracted with General Electric, Pacific Northwest National Lab and New Jersey Institute of Technology to conduct research in this project. The Iowa Corn Promotion Board and General Electric provided cost share for the project. The purpose of this diverse collaboration was to integrate both the conversion and the polymer applications into one project and increase the likelihood of success. This project has led to additional collaborations among other polymer companies. The goals of the project were to develop a renewable route to isosorbide for commercialization that is economically competitive with all existing production technologies and to develop new applications for isosorbide in various products such as polymers and materials. Under this program a novel process for the production of isosorbide was developed and evaluated. The novel process converts corn based sorbitol into isosorbide using a solid catalyst with integrated water removal and product recovery. In addition the work under this program has identified several novel products based on isosorbide chemistries. These market applications include: epoxy resins, UV stabilizers, plasticizers and polyesters. These market applications have commercial interest within the current polymer industry. This report contains an overview summary of the accomplishments. Six inventions and four patent applications have been written as a result of this project. Additional data will be published in the patent applications. The data developed at New Jersey Institute of Technology was presented at two technical conferences held in June of 2006. Several companies have made inquiries about using this material in their products.

  17. Alkene Isomerization Using a Solid Acid as Activator and Support for a Homogeneous Catalyst

    ERIC Educational Resources Information Center

    Seen, Andrew J.

    2004-01-01

    An upper-level undergraduate experiment that, in addition to introducing students to catalysis using an air sensitive transition-metal complex, introduces the use of a solid acid as an activator and support for the catalyst is developed. The increased stability acquired in the course of the process affords the opportunity to characterize the…

  18. Synthesis, crystal growth, solubility, structural, optical, dielectric and microhardness studies of Benzotriazole-4-hydroxybenzoic acid single crystals

    NASA Astrophysics Data System (ADS)

    Silambarasan, A.; Krishna Kumar, M.; Thirunavukkarasu, A.; Mohan Kumar, R.; Umarani, P. R.

    2015-06-01

    Organic Benzotriazole-4-hydroxybenzoic acid (BHBA), a novel second-order nonlinear optical single crystal was grown by solution growth method. The solubility and nucleation studies were performed for BHBA crystal at different temperatures 30, 35, 40 45 and 50 °C. Single crystal X-ray diffraction study reveals that the BHBA belongs to Pna21 space group of orthorhombic crystal system. The crystal perfection of BHBA was examined from powder and high resolution X-ray diffraction analysis. UV-visible and photoluminescence spectra were recorded to study its transmittance and excitation, emission behaviors respectively. Kurtz powder second harmonic generation test reveals that, the frequency conversion efficiency of BHBA is 3.7 times higher than that of potassium dihydrogen phosphate (KDP) crystal. The dielectric constant and dielectric loss values were estimated for BHBA crystal at various temperatures and frequencies. The mechanical property of BHBA crystal was studied on (110), (010) and (012) planes by using Vicker's microhardness test. The chemical etching study was performed on (012) facet of BHBA crystal to analyze its growth feature.

  19. Water-soluble N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride as a nucleic acids vector for cell transfection.

    PubMed

    Faizuloev, Evgeny; Marova, Anna; Nikonova, Alexandra; Volkova, Irina; Gorshkova, Marina; Izumrudov, Vladimir

    2012-08-01

    To endow the cationic polysaccharides with solubility in the whole pH-range without loss of functionality of the amino groups, different chitosan samples were treated with glycidyltrimethylammonium chloride. Each modified unit of the exhaustively alkylated quaternized chitosan (QCht) contained both quaternary and secondary amino groups. The intercalated dye displacement assay and ζ-potential measurements implied stability of QCht polyplexes at physiological conditions and protonation of the secondary amino groups in slightly acidic media which is favorable for transfection according to proton sponge mechanism. The cytotoxicity and transfection efficacy increased with the chain lengthening. Nevertheless, the longest chains of QCht, 250 kDa were less toxic than PEI for COS-1 cells and revealed comparable and even significantly higher transfection activity of siRNA and plasmid DNA, respectively. Thus, highly polymerized QCht (250 kDa) provided the highest level of the plasmid DNA transfection being 5 and 80 times more active than QCht (100 kDa) and QCht (50 kDa), respectively, and 4-fold more effective than PEI, 25 kDa. The established influence of QCht molecular weight on toxicity and transfection efficacy allows elaborating polysaccharide vectors that possess rational balance of these characteristics. PMID:24750918

  20. Effect of the duration of prefeeding on amino acid digestibility of wheat distillers dried grains with solubles in broiler chicken.

    PubMed

    Kluth, H; Rodehutscord, M

    2010-04-01

    The objective of this study was to determine the effect of the duration of prefeeding on prececal amino acid (AA) digestibility of wheat distillers dried grains with solubles (DDGS) in broilers. The experimental diets with DDGS at levels of 0, 10, and 20% were offered ad libitum for 7, 5, and 3 d, starting on 14, 16, and 18 d of age. Titanium dioxide was used as an indigestible marker. Six pens of 10 birds were allocated to each treatment. Digesta was sampled on a pen basis from the distal two-thirds of the intestine section between Meckel's diverticulum and 2 cm anterior to the ileo-ceca-colonic junction. Ingested and digested amounts of AA were determined for each pen. Digestibility of AA in the diets was not significantly affected by the duration of prefeeding but was significantly reduced by inclusion of DDGS. Digestibility of AA in DDGS was determined by using a linear regression approach. The digestibility of AA in DDGS ranged from 76% (Arg, 5 d of feeding) to 33% (Asp, 3 d of feeding). There was no significant effect of prefeeding time on AA digestibility of DDGS. Lysine digestibility of DDGS was 72%. The mean digestibility of the AA Arg, Cys, Ile, Leu, Lys, Met, Phe, Thr, and Val of DDGS across the 3 prefeeding times was 66%. This study gave evidence that 3 d of prefeeding a diet is sufficient in studying prececal AA digestibility in broilers when low-digestible feeds are used. PMID:20308399

  1. Acid-Soluble Internal Capsules for Closed-Face Cassette Elemental Sampling and Analysis of Workplace Air

    PubMed Central

    Harper, Martin; Ashley, Kevin

    2013-01-01

    Airborne particles that are collected using closed-face filter cassettes (CFCs), which are used widely in the sampling of workplace aerosols, can deposit in places other than on the filter and thereby may not be included in the ensuing analysis. A technique for ensuring that internal non-filter deposits are included in the analysis is to collect airborne particles within an acid-soluble internal capsule that, following sampling, can be dissolved along with the filter for subsequent elemental analysis. An interlaboratory study (ILS) was carried out to evaluate the use of cellulosic CFC capsule inserts for their suitability in the determination of trace elements in airborne samples. The ILS was performed in accordance with an applicable ASTM International standard practice, ASTM E691, which describes statistical procedures for investigating interlaboratory precision. Performance evaluation materials consisted of prototype cellulose acetate capsules attached to mixed-cellulose ester filters. Batches of capsules were dosed with Pb-containing materials (standard aqueous solutions, and certified reference material soil and paint). Also, aerosol samples containing nine target analyte elements (As, Cd, Co, Cr, Cu, Fe, Pb, Mn, and Ni) were generated using a multiport sampler; various concentrations and sampling times were employed to yield samples fortified at desired loading levels. Triplicates of spiked capsules at three different loadings were conveyed to each volunteer laboratory; loading levels were unknown to the participants. The laboratories were asked to prepare the samples by acid dissolution and to analyze aliquots of extracted samples by atomic spectrometry in accordance with applicable ASTM International Standards. Participants were asked to report their results in units of μg of each target element per sample. For the elements investigated, interlaboratory precision and recovery estimates from the participating laboratories demonstrated the utility of the

  2. Distribution of soluble and microsomal epoxide hydrolase in the mouse brain and its contribution to cerebral epoxyeicosatrienoic acid metabolism.

    PubMed

    Marowsky, A; Burgener, J; Falck, J R; Fritschy, J-M; Arand, M

    2009-10-01

    Epoxide hydrolases comprise a family of enzymes important in detoxification and conversion of lipid signaling molecules, namely epoxyeicosatrienoic acids (EETs), to their supposedly less active form, dihydroxyeicosatrienoic acids (DHETs). EETs control cerebral blood flow, exert analgesic, anti-inflammatory and angiogenic effects and protect against ischemia. Although the role of soluble epoxide hydrolase (sEH) in EET metabolism is well established, knowledge on its detailed distribution in rodent brain is rather limited. Here, we analyzed the expression pattern of sEH and of another important member of the EH family, microsomal epoxide hydrolase (mEH), in mouse brain by immunohistochemistry. To investigate the functional relevance of these enzymes in brain, we explored their individual contribution to EET metabolism in acutely isolated brain cells from respective EH -/- mice and wild type littermates by mass spectrometry. We find sEH immunoreactivity almost exclusively in astrocytes throughout the brain, except in the central amygdala, where neurons are also positive for sEH. mEH immunoreactivity is abundant in brain vascular cells (endothelial and smooth muscle cells) and in choroid plexus epithelial cells. In addition, mEH immunoreactivity is present in specific neuronal populations of the hippocampus, striatum, amygdala, and cerebellum, as well as in a fraction of astrocytes. In freshly isolated cells from hippocampus, where both enzymes are expressed, sEH mediates the bulk of EET metabolism. Yet we observe a significant contribution of mEH, pointing to a novel role of this enzyme in the regulation of physiological processes. Furthermore, our findings indicate the presence of additional, hitherto unknown cerebral epoxide hydrolases. Taken together, cerebral EET metabolism is driven by several epoxide hydrolases, a fact important in view of the present targeting of sEH as a potential therapeutic target. Our findings suggest that these different enzymes have

  3. Monodispersed Hollow SO3H-Functionalized Carbon/Silica as Efficient Solid Acid Catalyst for Esterification of Oleic Acid.

    PubMed

    Wang, Yang; Wang, Ding; Tan, Minghui; Jiang, Bo; Zheng, Jingtang; Tsubaki, Noritatsu; Wu, Mingbo

    2015-12-01

    SO3H-functionalized monodispersed hollow carbon/silica spheres (HS/C-SO3H) with primary mesopores were prepared with polystyrene as a template and p-toluenesulfonic acid (TsOH) as a carbon precursor and -SO3H source simultaneously. The physical and chemical properties of HS/C-SO3H were characterized by N2 adsorption, TEM, SEM, XPS, XRD, Raman spectrum, NH3-TPD, element analysis and acid-base titration techniques. As a solid acid catalyst, HS/C-SO3H shows excellent performance in the esterification of oleic acid with methanol, which is a crucial reaction in biodiesel production. The well-defined hollow architecture and enhanced active sites accessibility of HS/C-SO3H guarantee the highest catalytic performance compared with the catalysts prepared by activation of TsOH deposited on the ordered mesoporous silicas SBA-15 and MCM-41. At the optimized conditions, high conversion (96.9%) was achieved and no distinct activity drop was observed after 5 recycles. This synthesis strategy will provide a highly effective solid acid catalyst for green chemical processes.

  4. Monodispersed Hollow SO3H-Functionalized Carbon/Silica as Efficient Solid Acid Catalyst for Esterification of Oleic Acid.

    PubMed

    Wang, Yang; Wang, Ding; Tan, Minghui; Jiang, Bo; Zheng, Jingtang; Tsubaki, Noritatsu; Wu, Mingbo

    2015-12-01

    SO3H-functionalized monodispersed hollow carbon/silica spheres (HS/C-SO3H) with primary mesopores were prepared with polystyrene as a template and p-toluenesulfonic acid (TsOH) as a carbon precursor and -SO3H source simultaneously. The physical and chemical properties of HS/C-SO3H were characterized by N2 adsorption, TEM, SEM, XPS, XRD, Raman spectrum, NH3-TPD, element analysis and acid-base titration techniques. As a solid acid catalyst, HS/C-SO3H shows excellent performance in the esterification of oleic acid with methanol, which is a crucial reaction in biodiesel production. The well-defined hollow architecture and enhanced active sites accessibility of HS/C-SO3H guarantee the highest catalytic performance compared with the catalysts prepared by activation of TsOH deposited on the ordered mesoporous silicas SBA-15 and MCM-41. At the optimized conditions, high conversion (96.9%) was achieved and no distinct activity drop was observed after 5 recycles. This synthesis strategy will provide a highly effective solid acid catalyst for green chemical processes. PMID:26588826

  5. Solid-State 17O NMR Study of Benzoic Acid Adsorption On Metal Oxide Surfaces

    SciTech Connect

    Hagaman, Edward {Ed} W; Chen, Banghao; Jiao, Jian; Parsons, Williams

    2012-01-01

    Solid-state 17O NMR spectra of 17O-labeled benzoic and anisic acids are reported and benzoic acid is used to probe the surface of metal oxides. Complexes formed when benzoic acid is dry-mixed with mesoporous silica, and nonporous titania and alumina are characterized. Chemical reactions with silica are not observed. The nature of benzoic acid on silica is a function of the water content of the oxide. The acid disperses in the pores of the silica if the silica is in equilibrium with ambient laboratory humidity. The acid displays high mobility as evidenced by a liquid-like, Lorentzian resonance. Excess benzoic acid remains as the crystalline hydrogen-bonded dimer. Benzoic acid reacts with titania and alumina surfaces in equilibrium with laboratory air to form the corresponding titanium and aluminum benzoates. In both materials the oxygen of the 17O-labeled acid is bound to the metal, showing the reaction proceeds by bond formation between oxygen deficient metal sites and the oxygen of the carboxylic acid. 27Al MAS NMR confirms this mechanism for the reaction on alumina. Dry mixing of benzoic acid with alumina rapidly quenches pentacoordinate aluminum sites, excellent evidence that these sites are confined to the surface of the alumina particles.

  6. Supported zirconium sulfate on carbon nanotubes as water-tolerant solid acid catalyst

    SciTech Connect

    Juan, Joon Ching; Jiang Yajie; Meng Xiujuan; Cao Weiliang; Yarmo, Mohd Ambar; Zhang Jingchang . E-mail: zhangjc1@mail.buct.edu.cn

    2007-07-03

    A new solid acid of zirconium sulfate (CZ) was successfully supported on carbon nanotube (CNT) for esterification reaction. Preparation conditions of the supported CZ have been investigated, to obtain highest catalytic activity for esterification reaction. XRD, TEM, BET, X-ray photoelectron spectra (XPS) and in situ FTIR analysis has also been carried out to understand the characteristics of the catalyst. In the esterification of acrylic acid with n-octanol, the supported CZ exhibited high catalytic activity and stability. The catalytic activity was nearly unchanged during four times of reuse. XRD and TEM analysis indicated that CZ was finely dispersed on CNT. XPS analysis shows that the CZ species was preserved and the chemical environment of the CZ has changed after loaded on CNT. This finding show that CNT as CZ support is an efficient water-tolerant solid acid.

  7. Solid supported in situ derivatization extraction of acidic degradation products of nerve agents from aqueous samples.

    PubMed

    Chinthakindi, Sridhar; Purohit, Ajay; Singh, Varoon; Tak, Vijay; Dubey, D K; Pardasani, Deepak

    2014-09-12

    This study deals with the solid supported in situ derivatization extraction of acidic degradation products of nerve agents present in aqueous samples. Target analytes were alkyl alkylphosphonic acids and alkylphosphonic acids, which are important environmental signatures of nerve agents. The method involved tert-butyldimethylchlorosilane mediated in situ silylation of analytes on commercially available diatomaceous solid phase extraction cartridges. Various parameters such as derivatizing reagent, its concentration, reaction time, temperature and eluting solvent were optimized. Recoveries of the analytes were determined by GC-MS which ranged from 60% to 86%. The limits of detection (LOD) and limit of quantification (LOQ) with selected analytes were achieved down to 78 and 213ngmL(-1) respectively, in selected ion monitoring mode. The successful applicability of method was also demonstrated on samples of biological origin such as plasma and to the samples received in 34th official proficiency test conducted by the Organization for Prohibition the of Chemical Weapons. PMID:25103280

  8. Solubility of Organic Compounds

    ERIC Educational Resources Information Center

    James, K. C.

    1972-01-01

    Outlines factors to be considered in choosing suitable solvents for non-electrolytes and salts of weak acids and bases. Describes how, in some simple situation, the degree of solubility can be estimated. (Author/DF)

  9. Extent and mechanism of solvation and partitioning of isomers of substituted benzoic acids: a thermodynamic study in the solid state and in solution.

    PubMed

    Perlovich, German L; Volkova, Tatyana V; Manin, Alex N; Bauer-Brandl, Annette

    2008-09-01

    Temperature dependency of saturated vapour pressure and thermochemical characteristics of fusion processes for 2-, 3- and 4-methoxybenzoic acids (anisic acids) were measured and thermodynamic functions of sublimation, fusion, and evaporation calculated. A new approach to split specific and nonspecific energetic terms in the crystal lattice was developed. For methoxybenzoic acid isomers as well as for a number of analogous molecules, a parameter describing molecular packing density by the ratio of free volume of the molecules in the crystal lattice and van der Waals molecular volume is defined. Its relationship to Gibbs energy of sublimation and to the respective melting points was analysed. Temperature dependencies of solubility in buffers with pH 2.0 and 7.4, n-octanol and n-hexane were measured. The thermodynamic functions of solubility, solvation and transfer processes were deduced. Concentration dependence of partition coefficients for the outlined isomers was measured. Specific and nonspecific solvation terms were distinguished using the transfer from the 'inert' n-hexane to the other solvents. Comparison analysis of specific and nonspecific interactions in the solid state and in solution was carried out. A diagram enabling analysis of the mechanism of the partitioning process was applied. It was found that position of substituents essentially affects the mechanism of partitioning in buffer pH 2.0, however, at pH 7.4, the mechanism is independent of the position of the substituent. PMID:18200548

  10. Direct production of biodiesel from high-acid value Jatropha oil with solid acid catalyst derived from lignin

    PubMed Central

    2011-01-01

    Background Solid acid catalyst was prepared from Kraft lignin by chemical activation with phosphoric acid, pyrolysis and sulfuric acid. This catalyst had high acid density as characterized by scanning electron microscope (SEM), energy-dispersive x-ray spectrometry (EDX) and Brunauer, Emmett, and Teller (BET) method analyses. It was further used to catalyze the esterification of oleic acid and one-step conversion of non-pretreated Jatropha oil to biodiesel. The effects of catalyst loading, reaction temperature and oil-to-methanol molar ratio, on the catalytic activity of the esterification were investigated. Results The highest catalytic activity was achieved with a 96.1% esterification rate, and the catalyst can be reused three times with little deactivation under optimized conditions. Biodiesel production from Jatropha oil was studied under such conditions. It was found that 96.3% biodiesel yield from non-pretreated Jatropha oil with high-acid value (12.7 mg KOH/g) could be achieved. Conclusions The catalyst can be easily separated for reuse. This single-step process could be a potential route for biodiesel production from high-acid value oil by simplifying the procedure and reducing costs. PMID:22145867

  11. Citric and gluconic acid production from fig by Aspergillus niger using solid-state fermentation.

    PubMed

    Roukas, T

    2000-12-01

    The production of citric and gluconic acids from fig by Aspergillus niger ATCC 10577 in solid-state fermentation was investigated. The maximal citric and gluconic acids concentration (64 and 490 g/kg dry figs, respectively), citric acid yield (8%), and gluconic acid yield (63%) were obtained at a moisture level of 75%, initial pH 7.0, temperature 30 degrees C, and fermentation time in 15 days. However, the highest biomass dry weight (40 g/kg wet substrate) and sugar utilization (90%) were obtained in cultures grown at 35 degrees C. The addition of 6% (w/w) methanol into substrate increased the concentration of citric and gluconic acid from 64 and 490 to 96 and 685 g/kg dry fig, respectively.

  12. A solid acid esterification catalyst which reduces waste and increases yields

    SciTech Connect

    Lundquist, E.G.

    1993-12-31

    Recent research on polymeric catalysts has led to the development of a new solid acid esterification catalyst which is highly active for the esterification of fatty acids and maleic anhydride at elevated temperatures. The use of this catalyst eliminates the need for a final neutralization step which is required when using traditional homogenous acid (H{sub 2}SO{sub 4} and HCl) catalysts. This neutralization step generates large amounts of waste salts and hurts efficiency since unconsumed organic acid reactants are also neutralized. In the high temperature esterification reactions studied here, the production of dialkyl ether by-products from the acid catalyzed self-condensation of alcohol is also greatly reduced allowing for both high activity and selectivity.

  13. Effect of Periodic Water Addition on Citric Acid Production in Solid State Fermentation

    NASA Astrophysics Data System (ADS)

    Utpat, Shraddha S.; Kinnige, Pallavi T.; Dhamole, Pradip B.

    2013-09-01

    Water addition is one of the methods used to control the moisture loss in solid state fermentation (SSF). However, none of the studies report the timing of water addition and amount of water to be added in SSF. Therefore, this work was undertaken with an objective to evaluate the performance of periodic water addition on citric acid production in SSF. Experiments were conducted at different moistures (50-80 %) and temperatures (30-40 °C) to simulate the conditions in a fermenter. Citric acid production by Aspergillus niger (ATCC 9029) using sugarcane baggase was chosen as a model system. Based on the moisture profile, citric acid and sugar data, a strategy was designed for periodic addition of water. Water addition at 48, 96, 144 and 192 h enhanced the citric acid production by 62 % whereas water addition at 72, 120, and 168 h increased the citric acid production by just 17 %.

  14. Solid acid-catalyzed depolymerization of barley straw driven by ball milling.

    PubMed

    Schneider, Laura; Haverinen, Jasmiina; Jaakkola, Mari; Lassi, Ulla

    2016-04-01

    This study describes a time and energy saving, solvent-free procedure for the conversion of lignocellulosic barley straw into reducing sugars by mechanocatalytical pretreatment. The catalytic conversion efficiency of several solid acids was tested which revealed oxalic acid dihydrate as a potential catalyst with high conversion rate. Samples were mechanically treated by ball milling and subsequently hydrolyzed at different temperatures. The parameters of the mechanical treatment were optimized in order to obtain sufficient amount of total reducing sugar (TRS) which was determined following the DNS assay. Additionally, capillary electrophoresis (CE) and Fourier transform infrared spectrometry (FT-IR) were carried out. Under optimal conditions TRS 42% was released using oxalic acid dihydrate as a catalyst. This study revealed that the acid strength plays an important role in the depolymerization of barley straw and in addition, showed, that the oxalic acid-catalyzed reaction generates low level of the degradation product 5-hydroxymethylfurfural (HMF). PMID:26859328

  15. Proton transfer reactions between nitric acid and acetone, hydroxyacetone, acetaldehyde and benzaldehyde in the solid phase.

    PubMed

    Lasne, Jérôme; Laffon, Carine; Parent, Philippe

    2012-12-01

    The heterogeneous and homogeneous reactions of acetone, hydroxyacetone, acetaldehyde and benzaldehyde with solid nitric acid (HNO(3)) films have been studied with Reflection-Absorption Infrared Spectroscopy (RAIRS) under Ultra-High Vacuum (UHV) conditions in the 90-170 K temperature range. In the bulk or at the surface of the films, nitric acid transfers its proton to the carbonyl function of the organic molecules, producing protonated acetone-H(+), hydroxyacetone-H(+), acetaldehyde-H(+) and benzaldehyde-H(+), and nitrate anions NO(3)(-), a reaction not observed when nitric acid is previously hydrated [J. Lasne, C. Laffon and Ph. Parent, Phys. Chem. Chem. Phys., 2012, 14, 697]. This provides a molecular-scale description of the carbonyl protonation reaction in an acid medium, the first step of the acid-catalyzed condensation of carbonyl compounds, fuelling the growth of secondary organic aerosols (SOA) in the atmosphere.

  16. Development of micro-fibrous solid dispersions of poorly water-soluble drugs in sucrose using temperature-controlled centrifugal spinning

    PubMed Central

    Marano, Stefania; Barker, Susan Anne; Raimi-Abraham, Bahijja Tolulope; Missaghi, Shahrzad; Rajabi-Siahboomi, Ali; Craig, Duncan Q.M.

    2016-01-01

    Solid dispersion technology represents a successful approach to addressing the bioavailability issues caused by the low aqueous solubility of many Biopharmaceutics Classification System (BCS) Class II drugs. In this study, the use of high-yield manufacture of fiber-based dispersion is explored as an alternative approach to monolith production methods. A temperature-controlled solvent-free centrifugal spinning process was used to produce sucrose-based microfibers containing the poorly water-soluble drugs olanzapine and piroxicam (both BCS Class II); these were successfully incorporated into the microfibers and the basic characteristics of fiber diameter, glassy behavior, drug loading capacity and drug–sucrose interaction assessment were measured. Scanning electron microscopy revealed that bead-free drug-loaded microfibers with homogenous morphology and diameter in the range of a few micrometers were prepared using our process. Differential scanning calorimetric and X-ray diffraction analyses showed that both drug and carrier were present in the amorphous state in the microfibers, although in the case of piroxicam-loaded microfibers, the presence of small amounts of crystalline drug was observed under polarized light microscopy and in Fourier transform infrared spectra. Drug dissolution performance was evaluated under both sink and non-sink conditions and was found to be significantly enhanced compared to the corresponding crystalline physical mixtures and pure drugs, with evidence of supersaturation behavior noted under non-sink conditions. This study has demonstrated that microfiber-based dispersions may be manufactured by the centrifugal spinning process and may possess characteristics that are favorable for the enhanced dissolution and oral absorption of drugs. PMID:27012901

  17. Development of micro-fibrous solid dispersions of poorly water-soluble drugs in sucrose using temperature-controlled centrifugal spinning.

    PubMed

    Marano, Stefania; Barker, Susan Anne; Raimi-Abraham, Bahijja Tolulope; Missaghi, Shahrzad; Rajabi-Siahboomi, Ali; Craig, Duncan Q M

    2016-06-01

    Solid dispersion technology represents a successful approach to addressing the bioavailability issues caused by the low aqueous solubility of many Biopharmaceutics Classification System (BCS) Class II drugs. In this study, the use of high-yield manufacture of fiber-based dispersion is explored as an alternative approach to monolith production methods. A temperature-controlled solvent-free centrifugal spinning process was used to produce sucrose-based microfibers containing the poorly water-soluble drugs olanzapine and piroxicam (both BCS Class II); these were successfully incorporated into the microfibers and the basic characteristics of fiber diameter, glassy behavior, drug loading capacity and drug-sucrose interaction assessment were measured. Scanning electron microscopy revealed that bead-free drug-loaded microfibers with homogenous morphology and diameter in the range of a few micrometers were prepared using our process. Differential scanning calorimetric and X-ray diffraction analyses showed that both drug and carrier were present in the amorphous state in the microfibers, although in the case of piroxicam-loaded microfibers, the presence of small amounts of crystalline drug was observed under polarized light microscopy and in Fourier transform infrared spectra. Drug dissolution performance was evaluated under both sink and non-sink conditions and was found to be significantly enhanced compared to the corresponding crystalline physical mixtures and pure drugs, with evidence of supersaturation behavior noted under non-sink conditions. This study has demonstrated that microfiber-based dispersions may be manufactured by the centrifugal spinning process and may possess characteristics that are favorable for the enhanced dissolution and oral absorption of drugs. PMID:27012901

  18. Development of micro-fibrous solid dispersions of poorly water-soluble drugs in sucrose using temperature-controlled centrifugal spinning.

    PubMed

    Marano, Stefania; Barker, Susan Anne; Raimi-Abraham, Bahijja Tolulope; Missaghi, Shahrzad; Rajabi-Siahboomi, Ali; Craig, Duncan Q M

    2016-06-01

    Solid dispersion technology represents a successful approach to addressing the bioavailability issues caused by the low aqueous solubility of many Biopharmaceutics Classification System (BCS) Class II drugs. In this study, the use of high-yield manufacture of fiber-based dispersion is explored as an alternative approach to monolith production methods. A temperature-controlled solvent-free centrifugal spinning process was used to produce sucrose-based microfibers containing the poorly water-soluble drugs olanzapine and piroxicam (both BCS Class II); these were successfully incorporated into the microfibers and the basic characteristics of fiber diameter, glassy behavior, drug loading capacity and drug-sucrose interaction assessment were measured. Scanning electron microscopy revealed that bead-free drug-loaded microfibers with homogenous morphology and diameter in the range of a few micrometers were prepared using our process. Differential scanning calorimetric and X-ray diffraction analyses showed that both drug and carrier were present in the amorphous state in the microfibers, although in the case of piroxicam-loaded microfibers, the presence of small amounts of crystalline drug was observed under polarized light microscopy and in Fourier transform infrared spectra. Drug dissolution performance was evaluated under both sink and non-sink conditions and was found to be significantly enhanced compared to the corresponding crystalline physical mixtures and pure drugs, with evidence of supersaturation behavior noted under non-sink conditions. This study has demonstrated that microfiber-based dispersions may be manufactured by the centrifugal spinning process and may possess characteristics that are favorable for the enhanced dissolution and oral absorption of drugs.

  19. Radionuclide Leaching from Residual Solids Remaining after Acid Dissolution of Composite K East Canister Sludge

    SciTech Connect

    Delegard, C.H.; Rinehart, D.E.; Soderquist, C.Z.; Fadeff, S.K.

    1999-04-02

    Laboratory tests were performed to examine mixed nitric/hydrofluoric acid leach treatments for decontaminating dissolver residual solids (KECDVSR24H-2) produced during a 20- to 24-hr dissolution of a composite K East (KE) Basin canister sludge in 95 C 6 M nitric acid (HNO{sub 3}). The scope of this testing has been described in Section 4.5 of ''Testing Strategy to Support the Development of K Basin Sludge Treatment Process'' (Flament 1998). Radionuclides sorbed or associated with the residual solids generated in the K Basin sludge treatment process can restrict disposal of this solid to the Environmental Restoration Disposal Facility (ERDF). The starting dissolver residual solid for this testing, KECDVSR24H-2, contains radionuclides at concentrations which exceed the ERDF Waste Acceptance Criteria for TRU by about a factor of 70, for {sup 239}Pu by a factor of 200, and for {sup 241}Am by a factor of 50. The solids also exceed the ERDF criterion for {sup 137}Cs by a factor of 2 and uranium by a factor of 5. Therefore, the radionuclides of greatest interest in this leaching study are first {sup 239}Pu and {sup 241}Am (both components of TRU) and then uranium and {sup 137}Cs.

  20. Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition.

    PubMed

    Nakayama, Hirokazu; Hayashi, Aki

    2014-01-01

    The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids. PMID:25080007

  1. Hydrothermal preparation and characterization of novel corncob-derived solid acid catalysts.

    PubMed

    Ma, Huan; Li, Jiabao; Liu, Weiwei; Cheng, Beijiu; Cao, Xiaoyan; Mao, Jingdong; Zhu, Suwen

    2014-06-11

    Novel corncob-derived solid acid catalysts were successfully synthesized for the first time by the hydrothermal method. The influences of different preparation conditions were investigated, and the structure-function relationships of the resulting catalysts were also discussed on the basis of the analysis of structure and composition. In comparison to conventional solid acid catalysts, the corncob-derived catalyst synthesized under optimized conditions exhibited higher catalytic activity in esterification reactions, yielding nearly 90% methyl oleate in only 2 h. The catalyst retained satisfactory catalytic activity for esterification, even after 8 reaction cycles. Solid-state magic angle spinning (MAS) (13)C nuclear magnetic resonance (NMR) investigations further indicated that the catalyst was composed of polycyclic aromatic carbon sheets bearing -SO3H, -COOH, and -OH groups in adequate amounts and with proper proportions, contributing to its excellent catalytic activity. This work provides a green method to synthesize solid acid catalysts from biomass wastes and may contribute to a holistic approach for biomass conversion. PMID:24820344

  2. Effects of soluble and insoluble fractions from bilberries, black currants, and raspberries on short-chain fatty acid formation, anthocyanin excretion, and cholesterol in rats.

    PubMed

    Jakobsdottir, Greta; Nilsson, Ulf; Blanco, Narda; Sterner, Olov; Nyman, Margareta

    2014-05-14

    Dietary fiber and flavonoids, important components in berries, are suggested to improve metabolic health. This study investigates whether soluble and insoluble fractions isolated from bilberry, black currant, and raspberry affect the formation of short-chain fatty acids (SCFAs), uptake and excretion of flavonoids, and levels of cholesterol differently. Cecal SCFA pools were higher in rats fed the soluble than the insoluble fractions (525 vs 166 μmol, P < 0.001), whereas higher concentrations of butyric acid were found in the distal colon and serum of rats fed the insoluble fractions (5 vs 3 μmol/g and 58 vs 29 μmol/L, respectively, P < 0.001). The soluble bilberry fraction gave lower amounts of liver cholesterol (56 mg) than the other berry fractions (87 ± 5 mg), formed the highest amount of SCFAs (746 vs 266 ± 21 μmol), and contributed the highest intake of anthocyanins. Cyanidin-3-glucoside monoglucuronide was detected in the urine of all groups, whereas anthocyanins were found only in groups fed soluble black currant and raspberry.

  3. Dissolution kinetics of a three-component solid II: benzoic acid, salicylic acid, and salicylamide.

    PubMed

    Parrott, E L; Simpson, M; Flanagan, D R

    1983-07-01

    The dissolution rates of each component in compressed spheres consisting of three components were measured under sink conditions. The observed dissolution rates of benzoic acid, salicylic acid, and salicylamide compare favorably to the predicted dissolution rates according to a previously presented kinetic model.

  4. Solid-Phase Spectrophotometric Analysis of 1-Naphthol Using Silica Functionalized with m-Diazophenylarsonic Acid

    NASA Astrophysics Data System (ADS)

    Zaitseva, Nataliya; Alekseev, Sergei; Zaitsev, Vladimir; Raks, Viktoria

    2016-03-01

    The m-aminophenylarsonic acid (m-APAA) was immobilized onto the silica gel surface with covalently grafted quaternary ammonium groups via ion exchange. The diazotization of ion-bonded m-APAA resulted in a new solid-phase spectrophotometric reagent for detection of 1-naphtol in environmental water samples. The procedure of solid-phase spectrophotometric analysis is characterized by 20 μg L-1 limit of detection (LOD) of 1-naphtol, up to 2000 concentration factor, and insensitivity to the presence of natural water components as well as to 30-fold excess of phenol, resorcinol, and catechol.

  5. Synthesis, chemical and enzymatic hydrolysis, and aqueous solubility of amino acid ester prodrugs of 3-carboranyl thymidine analogs for boron neutron capture therapy of brain tumors.

    PubMed

    Hasabelnaby, Sherifa; Goudah, Ayman; Agarwal, Hitesh K; abd Alla, Mosaad S M; Tjarks, Werner

    2012-09-01

    Various water-soluble L-valine-, L-glutamate-, and glycine ester prodrugs of two 3-Carboranyl Thymidine Analogs (3-CTAs), designated N5 and N5-2OH, were synthesized for Boron Neutron Capture Therapy (BNCT) of brain tumors since the water solubilities of the parental compounds proved to be insufficient in preclinical studies. The amino acid ester prodrugs were prepared and stored as hydrochloride salts. The water solubilities of these amino acid ester prodrugs, evaluated in phosphate buffered saline (PBS) at pH 5, pH 6 and pH 7.4, improved 48-6600 times compared with parental N5 and N5-2OH. The stability of the amino acid ester prodrugs was evaluated in PBS at pH 7.4, Bovine serum, and Bovine cerebrospinal fluid (CSF). The rate of the hydrolysis in all three incubation media depended primarily on the amino acid promoiety and, to a lesser extend, on the site of esterification at the deoxyribose portion of the 3-CTAs. In general, 3'-amino acid ester prodrugs were less sensitive to chemical and enzymatic hydrolysis than 5'-amino acid ester prodrugs and the stabilities of the latter decreased in the following order: 5'-valine > 5'-glutamate > 5'-glycine. The rate of the hydrolysis of the 5'-amino acid ester prodrugs in Bovine CSF was overall higher than in PBS and somewhat lower than in Bovine serum. Overall, 5'-glutamate ester prodrug of N5 and the 5'-glycine ester prodrugs of N5 and N5-2OH appeared to be the most promising candidates for preclinical BNCT studies. PMID:22889558

  6. The properties of solid Zn(II)-amino acid complexes in the form of suspensions.

    PubMed

    Dolińska, B

    2001-10-01

    An investigation was made into the experimental conditions for the formation of poorly soluble complexes of the divalent Zinc(II) combined with the following selected amino acids: tyrosine, tryptophan, cysteine, histidine, and alanine, in the form of suspensions for parenteral administration. The number of Zn(II)-binding sites in the amino acid (n) as well as the amino acid affinity to Zn(II) (Ka), were determined. Cysteine was found to have the highest number of Zn(II)-binding sites--3, whereas alanine the lowest--1. In the conditions described herein, Zn(II) amino acid complexes of diverse stability (durability) were obtained. The analysis of the kinetics of the binding revealed that the most stable complexes were those formed by Zn(II) in combination with tryptophan (Ka = 405.78 microM(-1) +/- 12.17), and with tyrosine (Ka = 343.88 microM +/- 22.35); whereas the least stable complexes were those formed by Zn(II) in combination with histidine (Ka = 29.90 microM +/- 4.78), and with alanine (Ka = 13.0 microM(-1) +/- 1.04). Cysteine formed complexes of intermediate stability (Ka = 168.53 microM(-1) +/- 12.36). The stability ofthe Zn(II) amino acid complexes obtained was conditioned by both the molecular weight (P = 0.033) of the amino acid and its isoelectric point (P < 0.001). PMID:11718265

  7. Catalytic hydrothermal pretreatment of corncob into xylose and furfural via solid acid catalyst.

    PubMed

    Li, Huiling; Deng, Aojie; Ren, Junli; Liu, Changyu; Lu, Qi; Zhong, Linjie; Peng, Feng; Sun, Runcang

    2014-04-01

    Selectively catalytic hydrothermal pretreatment of corncob into xylose and furfural has been developed in this work using solid acid catalyst (SO4(2-)/TiO2-ZrO2/La(3+)). The effects of corncob-to-water ratio, reaction temperature and residence time on the performance of catalytic hydrothermal pretreatment were investigated. Results showed that the solid residues contained mainly lignin and cellulose, which was indicative of the efficient removal of hemicelluloses from corncob by hydrothermal method. The prepared catalyst with high thermal stability and strong acid sites originated from the acid functional groups was confirmed to contribute to the hydrolysis of polysaccharides into monosaccharides followed by dehydration into furfural. Highest furfural yield (6.18 g/100g) could be obtained at 180°C for 120 min with 6.80 g/100g xylose yield when the corncob/water ratio of was 10:100. Therefore, selectively catalytic hydrothermal pretreatment of lignocellulosic biomass into important platform chemicals by solid acids is considered to be a potential treatment for biodiesel and chemical production.

  8. Short communication: Effect of conjugated linoleic acid on concentrations of fat-soluble vitamins in milk of lactating ewes.

    PubMed

    Zeitz, J O; Most, E; Eder, K

    2015-10-01

    Conjugated linoleic acids (CLA) are well known as milk fat-reducing feed supplements in diets for lactating ruminants. However, their effects on milk concentrations of fat-soluble vitamins are unknown. This study was performed to investigate the hypothesis that CLA affect the concentrations of retinol and tocopherol in ewe milk. For that purpose, group-housed Merino ewes (101 ± 13.7 kg) nursing twin lambs and fed with a hay:concentrate diet were supplemented with either 45 g of a rumen-protected CLA supplement containing 3.4 g of cis-9,trans-11-CLA and 3.4 g of trans-10,cis-12-CLA (CLA group, n=11) or with 45 g of a hydrogenated vegetable fat (control group, n=12) per ewe per day during the first 6 wk of lactation. Feed intake was recorded daily (concentrate) or weekly (hay) per group. Milk spot samples were collected at the beginning of the experiment (5 ± 2.4 d postpartum) and then weekly after lambs had been separated for 2 h from their mothers. The milk fat content was determined and feed and milk were analyzed for concentrations of α-, γ-, and δ-tocopherol and for retinol by HPLC. Dietary intake of tocopherol and retinol was similar in both groups. Feeding CLA decreased milk fat concentration by 23% on average, and during the first 3 wk of the study milk tocopherol concentration tended to be increased by feeding CLA (+17%), but retinol concentrations were not influenced. When related to milk fat, CLA feeding significantly increased both milk tocopherol (+40%) and retinol (+32%) and these effects were evident during the whole experimental period corresponding to the first half of lactation.

  9. Field measurement of acid gases and soluble anions in atmospheric particulate matter using a parallel plate wet denuder and an alternating filter-based automated analysis system.

    PubMed

    Boring, C Bradley; Al-Horr, Rida; Genfa, Zhang; Dasgupta, Pumendu K; Martin, Michael W; Smith, William F

    2002-03-15

    We present a new fully automated instrument for the measurement of acid gases and soluble anionic constituents of atmospheric particulate matter. The instrument operates in two independent parallel channels. In one channel, a wet denuder collects soluble acid gases; these are analyzed by anion chromatography (IC). In a second channel, a cyclone removes large particles and the aerosol stream is then processed by another wet denuder to remove potentially interfering gases. The particles are then collected by one of two glass fiber filters which are alternately sampled, washed, and dried. The washings are preconcentrated and analyzed by IC. Detection limits of low to subnanogram per cubic meter concentrations of most gaseous and particulate constituents can be readily attained. The instrument has been extensively field-tested; some field data are presented. Results of attempts to decipher the total anionic constitution of urban ambient aerosol by IC-MS analysis are also presented.

  10. Solid-state 17O NMR of pharmaceutical compounds: salicylic acid and aspirin.

    PubMed

    Kong, Xianqi; Shan, Melissa; Terskikh, Victor; Hung, Ivan; Gan, Zhehong; Wu, Gang

    2013-08-22

    We report solid-state NMR characterization of the (17)O quadrupole coupling (QC) and chemical shift (CS) tensors in five site-specifically (17)O-labeled samples of salicylic acid and o-acetylsalicylic acid (Aspirin). High-quality (17)O NMR spectra were obtained for these important pharmaceutical compounds under both static and magic angle spinning (MAS) conditions at two magnetic fields, 14.0 and 21.1 T. A total of 14 (17)O QC and CS tensors were experimentally determined for the seven oxygen sites in salicylic acid and Aspirin. Although both salicylic acid and Aspirin form hydrogen bonded cyclic dimers in the solid state, we found that the potential curves for the concerted double proton transfer in these two compounds are significantly different. In particular, while the double-well potential curve in Aspirin is nearly symmetrical, it is highly asymmetrical in salicylic acid. This difference results in quite different temperature dependencies in (17)O MAS spectra of the two compounds. A careful analysis of variable-temperature (17)O MAS NMR spectra of Aspirin allowed us to obtain the energy asymmetry (ΔE) of the double-well potential, ΔE = 3.0 ± 0.5 kJ/mol. We were also able to determine a lower limit of ΔE for salicylic acid, ΔE > 10 kJ/mol. These asymmetrical features in potential energy curves were confirmed by plane-wave DFT computations, which yielded ΔE = 3.7 and 17.8 kJ/mol for Aspirin and salicylic acid, respectively. To complement the solid-state (17)O NMR data, we also obtained solid-state (1)H and (13)C NMR spectra for salicylic acid and Aspirin. Using experimental NMR parameters obtained for all magnetic nuclei present in salicylic acid and Aspirin, we found that plane-wave DFT computations can produce highly accurate NMR parameters in well-defined crystalline organic compounds.

  11. Solid Polymer Electrolytes Based on Functionalized Tannic Acids from Natural Resources for All-Solid-State Lithium-Ion Batteries.

    PubMed

    Shim, Jimin; Bae, Ki Yoon; Kim, Hee Joong; Lee, Jin Hong; Kim, Dong-Gyun; Yoon, Woo Young; Lee, Jong-Chan

    2015-12-21

    Solid polymer electrolytes (SPEs) for all-solid-state lithium-ion batteries are prepared by simple one-pot polymerization induced by ultraviolet (UV) light using poly(ethylene glycol) methyl ether methacrylate (PEGMA) as an ion-conducting monomeric unit and tannic acid (TA)-based crosslinking agent and plasticizer. The crosslinking agent and plasticizer based on natural resources are obtained from the reaction of TA with glycidyl methacrylate and glycidyl poly(ethylene glycol), respectively. Dimensionally stable free-standing SPE having a large ionic conductivity of 5.6×10(-4)  Scm(-1) at room temperature can be obtained by the polymerization of PEGMA into P(PEGMA) with a very small amount (0.1 wt %) of the crosslinking agent and 2.0 wt % of the plasticizer. The ionic conductivity value of SPE with a crosslinked structure is one order of magnitude larger than that of linear P(PEGMA) in the waxy state.

  12. Conversion of carbohydrate biomass to γ-valerolactone by using water-soluble and reusable iridium complexes in acidic aq