Minimizing target interference in PK immunoassays: new approaches for low-pH-sample treatment.

PubMed

Partridge, Michael A; Pham, John; Dziadiv, Olena; Luong, Onson; Rafique, Ashique; Sumner, Giane; Torri, Albert

2013-08-01

Quantitating total levels of monoclonal antibody (mAb) biotherapeutics in serum using ELISA may be hindered by soluble targets. We developed two low-pH-sample-pretreatment techniques to minimize target interference. The first procedure involves sample pretreatment at pH <3.0 before neutralization and analysis in a target capture ELISA. Careful monitoring of acidification time is required to minimize potential impact on mAb detection. The second approach involves sample dilution into mild acid (pH ∼4.5) before transferring to an anti-human capture-antibody-coated plate without neutralization. Analysis of target-drug and drug-capture antibody interactions at pH 4.5 indicated that the capture antibody binds to the drug, while the drug and the target were dissociated. Using these procedures, total biotherapeutic levels were accurately measured when soluble target was >30-fold molar excess. These techniques provide alternatives for quantitating mAb biotherapeutics in the presence of a target when standard acid-dissociation procedures are ineffective.

Canine intestinal contents vs. simulated media for the assessment of solubility of two weak bases in the human small intestinal contents.

PubMed

Kalantzi, Lida; Persson, Eva; Polentarutti, Britta; Abrahamsson, Bertil; Goumas, Konstantinos; Dressman, Jennifer B; Reppas, Christos

2006-06-01

This study was conducted to assess the relative usefulness of canine intestinal contents and simulated media in the prediction of solubility of two weak bases (dipyridamole and ketoconazole) in fasted and fed human intestinal aspirates that were collected under conditions simulating those in bioavailability/bioequivalence studies. After administration of 250 mL of water or 500 mL of Ensure plus [both containing 10 mg/mL polyethylene glycol (PEG) 4000 as nonabsorbable marker], intestinal aspirates were collected from the fourth part of the duodenum of 12 healthy adults and from the mid-jejunum of four Labradors. Pooled samples were analyzed for PEG, pH, buffer capacity, osmolality, surface tension, pepsin, total carbohydrates, total protein content, bile salts, phospholipids, and neutral lipids. The shake-flask method was used to measure the solubility of dipyridamole and ketoconazole in pooled human and canine intestinal contents and in fasted-state-simulating intestinal fluid (FaSSIF) and fed-state-simulating intestinal fluid (FeSSIF) containing various bile salts and pH-buffering agents. For both compounds, solubility in canine contents may be predictive of human intralumenal solubility in the fasting state but not in the fed state. The poor agreement of results in canine and human aspirates can be attributed to the higher bile salt content in canine bile. Solubility in FaSSIF containing a mixture of bile salts from crude bile predicted satisfactorily the intralumenal solubility of both drugs in the fasted state in humans. Solubility in FeSSIF, regardless of the identity of bile salts or of the buffering species, deviated from intralumenal values in the fed human aspirates by up to 40%. This was attributed to the lack of lipolytic products in FeSSIF, the higher bile salt content of FeSSIF, and the lower pH of FeSSIF. FaSSIF containing a mixture of bile salts from crude bile, and FeSSIF containing lipolytic products and, perhaps, having lower bile salt content but slightly higher pH, should be more useful than canine intestinal aspirates for predicting intralumenal solubilities in humans.

Effect of soil organic matter on antimony bioavailability after the remediation process.

PubMed

Nakamaru, Yasuo Mitsui; Martín Peinado, Francisco José

2017-09-01

We evaluated the long-term (18 year) and short-term (4 weeks) changes of Sb in contaminated soil with SOM increase under remediation process. In the Aznalcóllar mine accident (1998) contaminated area, the remediation measurement implemented the Guadiamar Green Corridor, where residual pollution is still detected. Soils of the re-vegetated area (O2) with high pH and high SOM content, moderately re-vegetated area (O1) and unvegetated area (C) were sampled. Soil pH, CEC, SOM amount and soil Sb forms were evaluated. Soil Sb was measured as total, soluble, exchangeable, EDTA extractable, acid oxalate extractable, and pyro-phosphate extractable fractions. Further, the short-term effect of artificial organic matter addition was also evaluated with incubation study by adding compost to the sampled soil from C, O1 and O2 areas. After 4 weeks of incubation, soil chemical properties and Sb forms were evaluated. In re-vegetated area (O2), soil total Sb was two times lower than in unvegetated area (C); however, soluble, exchangeable, and EDTA extractable Sb were 2-8 times higher. The mobile/bioavailable Sb increase was also observed after 4 weeks of incubation with the addition of compost. Soluble, exchangeable, and EDTA extractable Sb was increased 2-4 times by compost addition. By the linear regression analysis, the significantly related factors for soluble, exchangeable, and EDTA extractable Sb values were pH, CEC, and SOM, respectively. Soluble Sb increase was mainly related to pH rise. Exchangeable Sb should be bound by SOM-metal complex and increased with CEC. EDTA extractable fraction should be increased with increase of SOM as SOM-Fe associated Sb complex. From these results, it was shown that increase of SOM under natural conditions or application of organic amendment under remediation process should increase availability of Sb to plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

pH Shifting alters solubility characteristics and thermal stability of soy protein isolate and its globulin fractions in different pH, salt concentration, and temperature conditions.

PubMed

Jiang, Jiang; Xiong, Youling L; Chen, Jie

2010-07-14

Soy protein isolate (SPI), beta-conglycinin (7S), and glycinin (11S) were subjected to pH-shifting treatments, that is, unfolding at pH 1.5 or 12.0 followed by refolding at pH 7.0, to induce molten globule structures. Treated samples were analyzed for protein solubility, thermal stability, and aggregation in 0, 0.1, and 0.6 M NaCl solutions at pH 2.0-8.0. The pH(12) shifting resulted in drastic increases (up to 2.5-fold) in SPI solubility in the pH 6.0-7.0 range, especially at 0 M NaCl. The pH(1.5) shifting had a generally lesser effect on solubility. 11S exhibited a solubility pattern similar to that of SPI, but the solubility of 7S was unaffected by pH shifting except at 0.6 M NaCl. The pH shifting, notably at pH 12.0, produced soluble, disulfide-linked polymers from 11S and reduced (P < 0.05) its enthalpy but not its temperature of denaturation. Soy proteins structurally altered by pH shifting had a reduced sensitivity to thermal aggregation.

Metastable and equilibrium phase diagrams of unconjugated bilirubin IXα as functions of pH in model bile systems: Implications for pigment gallstone formation.

PubMed

Berman, Marvin D; Carey, Martin C

2015-01-01

Metastable and equilibrium phase diagrams for unconjugated bilirubin IXα (UCB) in bile are yet to be determined for understanding the physical chemistry of pigment gallstone formation. Also, UCB is a molecule of considerable biomedical importance because it is a potent antioxidant and an inhibitor of atherogenesis. We employed principally a titrimetric approach to obtain metastable and equilibrium UCB solubilities in model bile systems composed of taurine-conjugated bile salts, egg yolk lecithin (mixed long-chain phosphatidylcholines), and cholesterol as functions of total lipid concentration, biliary pH values, and CaCl2 plus NaCl concentrations. Metastable and equilibrium precipitation pH values were obtained, and average pKa values of the two carboxyl groups of UCB were calculated. Added lecithin and increased temperature decreased UCB solubility markedly, whereas increases in bile salt concentrations and molar levels of urea augmented solubility. A wide range of NaCl and cholesterol concentrations resulted in no specific effects, whereas added CaCl2 produced large decreases in UCB solubilities at alkaline pH values only. UV-visible absorption spectra were consistent with both hydrophobic and hydrophilic interactions between UCB and bile salts that were strongly influenced by pH. Reliable literature values for UCB compositions of native gallbladder biles revealed that biles from hemolytic mice and humans with black pigment gallstones are markedly supersaturated with UCB and exhibit more acidic pH values, whereas biles from nonstone control animals and patients with cholesterol gallstone are unsaturated with UCB. Copyright © 2015 the American Physiological Society.

Metastable and equilibrium phase diagrams of unconjugated bilirubin IXα as functions of pH in model bile systems: Implications for pigment gallstone formation

PubMed Central

Berman, Marvin D.

2014-01-01

Metastable and equilibrium phase diagrams for unconjugated bilirubin IXα (UCB) in bile are yet to be determined for understanding the physical chemistry of pigment gallstone formation. Also, UCB is a molecule of considerable biomedical importance because it is a potent antioxidant and an inhibitor of atherogenesis. We employed principally a titrimetric approach to obtain metastable and equilibrium UCB solubilities in model bile systems composed of taurine-conjugated bile salts, egg yolk lecithin (mixed long-chain phosphatidylcholines), and cholesterol as functions of total lipid concentration, biliary pH values, and CaCl2 plus NaCl concentrations. Metastable and equilibrium precipitation pH values were obtained, and average pKa values of the two carboxyl groups of UCB were calculated. Added lecithin and increased temperature decreased UCB solubility markedly, whereas increases in bile salt concentrations and molar levels of urea augmented solubility. A wide range of NaCl and cholesterol concentrations resulted in no specific effects, whereas added CaCl2 produced large decreases in UCB solubilities at alkaline pH values only. UV-visible absorption spectra were consistent with both hydrophobic and hydrophilic interactions between UCB and bile salts that were strongly influenced by pH. Reliable literature values for UCB compositions of native gallbladder biles revealed that biles from hemolytic mice and humans with black pigment gallstones are markedly supersaturated with UCB and exhibit more acidic pH values, whereas biles from nonstone control animals and patients with cholesterol gallstone are unsaturated with UCB. PMID:25359538

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szcześ, Aleksandra, E-mail: aszczes@poczta.umcs.lublin.pl; Czemierska, Magdalena; Jarosz-Wilkołazka, Anna

Extracellular polymeric substance (EPS) extracted from Rhodococcus opacus bacterial strain was used as a matrix for calcium carbonate precipitation using the vapour diffusion method. The total exopolymer and water-soluble exopolymer fraction of different concentrations were spread on the mica surface by the spin-coating method. The obtained layers were characterized using the atomic force microscopy measurement and XPS analysis. The effects of polymer concentration, initial pH of calcium chloride solution and precipitation time on the obtained crystals properties were investigated. Raman spectroscopy and scanning electron microscopy were used to characterize the precipitated minerals. It was found that the type of precipitatedmore » CaCO{sub 3} polymorph and the crystal size depend on the kind of EPS fraction. The obtained results indicates that the water soluble fraction favours vaterite dissolution and calcite growth, whereas the total EPS stabilizes vaterite and this effect is stronger at basic pH. It seems to be due to different contents of the functional group of EPS fractions. - Highlights: • CaCO{sub 3} crystal size and polymorph can be controlled by EPS substance obtained from R. opacus. • The water soluble fraction favours vaterite dissolution and calcite growth. • The total EPS stabilizes vaterite. • This effect is stronger at basic pH.« less

Tetragonal Chicken Egg White Lysozyme Solubility in Sodium Chloride Solutions

NASA Technical Reports Server (NTRS)

Forsythe, Elizabeth L.; Judge, Russell A.; Pusey, Marc L.

1998-01-01

The solubility of chicken egg white lysozyme, crystallized in the tetragonal form was measured in sodium chloride solutions from 1.6 to 30.7 C, using a miniature column solubility apparatus. Sodium chloride solution concentrations ranged from 1 to 7% (w/v). The solutions were buffered with 0.1 M sodium acetate buffer with the solubility being measured at pH values in 0.2 pH unit increments in the range pH 4.0 to 5.4, with data also included at pH 4.5. Lysozyme solubility was found to increase with increases in temperature and decreasing salt concentration. Solution pH has a varied and unpredictable effect on solubility.

The Application of Active Paper Incorporated with Oleoresin of Cinnamon Leaf (Cinnamomum burmanii) Distillation Residues on Maintaining Dragon Fruits (Hylocereus costaricensis) Quality during Storage

NASA Astrophysics Data System (ADS)

Aziz, M. S. H.; Manuhara, G. J.; Utami, R.; Khasanah, L. U.

2018-03-01

The purpose of this study was to determine the effect of active paper placement methods on super red dragon fruits quality during storage at ambient temperature. The active papers were incorporated with oleoresin of cinnamon leaf distillation residues. Various active paper placement methods were applied such as wrapping, placed on the cardboard wall, placed cardboard pad, and scrap of paper on the sidelines. Weight loss, peel color, surface and flesh hardness, total titratable acid, soluble solid total, pH flesh fruit, and total plate count (TPC) of super red dragon fruits samples were investigated during 9 days storage. The result shows that active paper placement methods significantly affected the weight loss, surface firmness and color peel change of super red dragon fruits samples. However, active paper placement methods insignificantly affected the titrable acid total, soluble solid total, pH, flesh firmness and microbial spoilage of super red dragon fruits samples. The best method to maintain the super red dragon fruits quality was wrapping method.

Vertical nutrient and trace element migration in cambisoils after application of residues from anaerobic digestion of pig manure

NASA Astrophysics Data System (ADS)

Sager, Manfred; Unterfrauner, Hans

2013-04-01

Cambisols sampled in alpine pastures were packed into soil columns in order to monitor downward migration of nutrient and trace elements, applied within the residue from anaerobic digestion of a pig manure. 2 rain events per week were simulated. The manure added substantial amounts of K, ammonium, Na, Ca, P, S, Cl, B, Zn and Cu to the soil, whereas Mg, Mn, Ni, Cr, Pb, Cd and V were at the same level. In the eluates, total elemental composition as well as nitrate and ammonium were monitored. Addition of soluble Fe (at 1000 mg/l as FeCl3) decreased the release of soluble sulphate, but had no significant effect on the release of Fe and P. During subsequent rain events, exchangeable K remained enriched in the topsoil, wheras total sulfur moved to deeper layers. After 8 weeks, the columns were dismantled and analyzed for quasi-total and mobile fractions. Both in topsoils and subsoils, manure addition finally increased soil pH in case of low P soils, but decreased soil pH in case of high pH soils. Effects of manure applications on groundwater formation processes will be discussed.

Enzyme-resistant dextrins from potato starch for potential application in the beverage industry.

PubMed

Jochym, Kamila Kapusniak; Nebesny, Ewa

2017-09-15

The objective of this study was to produce soluble enzyme-resistant dextrins by microwave heating of potato starch acidified with small amounts of hydrochloric and citric acids and to characterize their properties. Twenty five samples were initially made and their solubility was determined. Three samples with the highest water solubility were selected for physico-chemical (dextrose equivalent, molecular weight distribution, pasting characteristics, retrogradation tendency), total dietary fiber (TDF) analysis, and stability tests. TDF content averaged 25%. Enzyme-resistant dextrins practically did not paste, even at 20% samples concentration, and were characterized by low retrogradation tendency. The stability of the samples, expressed as a percentage increase of initial and final reducing sugar content, at low pH and during heating at low pH averaged 10% and 15% of the initial value, respectively. The results indicate that microwave heating could be an effective and efficient method of producing highly-soluble, low-viscous, and enzyme-resistant potato starch dextrins. Copyright © 2017 Elsevier Ltd. All rights reserved.

The solubility of the tetragonal form of hen egg white lysozyme from pH 4.0 to 5.4

NASA Technical Reports Server (NTRS)

Cacioppo, Elizabeth; Pusey, Marc L.

1991-01-01

Hen egg white lysozyme solubilities in the presence of the tetragonal crystal form have been determined. Conditions investigated cover the pH range 4.0 to 5.4, varying from 2.0 to 7.0 percent NaCl concentrations and from 4 to 25 C. In all instances, the solubilities were found to increase with temperature and decrease with increasing salt concentration. The effects of pH were more complex, showing a decreasing solubility with increasing pH at low salt concentration and an increasing solubility with increasing pH at high salt concentration.

Evolution of some physicochemical and antioxidant properties of black garlic whole bulbs and peeled cloves.

PubMed

Toledano-Medina, M Angeles; Pérez-Aparicio, Jesús; Moreno-Rojas, Rafael; Merinas-Amo, Tania

2016-05-15

Black garlic was processed at three different temperatures of heat treatment (72°, 75° and 78°C) and close to 90% of relative humidity. Two types of material source were used: whole bulbs and peeled cloves. Total soluble solids content (°Brix), pH, water activity (aw), browning intensive (L value), total polyphenol content, antioxidant capacity and total polyphenol index of the raw and heated garlic were determined. This study showed the changes occurring in the physicochemical and antioxidant properties of the garlic during the heat-treatment evolution. The soluble solids content (°Brix) in garlic increased gradually and the pH decreased in whole bulbs and peeled garlics. The polyphenol content measured by the Folin-Ciocalteu method showed a significant increase during the heat-treatment in all the cases. Also, the antioxidant capacity measured by the ABTS radical increased significantly during the heat-treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of starters on chemical, biochemical, and sensory changes in Turkish White-brined cheese during ripening.

PubMed

Hayaloglu, A A; Guven, M; Fox, P F; McSweeney, P L H

2005-10-01

Turkish White-brined cheese was manufactured using Lactococcus strains (Lactococcus lactis ssp. lactis NCDO763 plus L. lactis ssp. cremoris SK11 and L. lactis ssp. lactis UC317 plus L. lactis ssp. cremoris HP) or without a starter culture, and ripened for 90 d. It was found that the use of starters significantly influenced the physical, chemical, biochemical, and sensory properties of the cheeses. Chemical composition, pH, and sensory properties of cheeses made with starter were not affected by the different starter bacteria. The levels of soluble nitrogen fractions and urea-PAGE of the pH 4.6-insoluble fractions were found to be significantly different at various stages of ripening. Urea-PAGE patterns of the pH 4.6-insoluble fractions of the cheeses showed that considerable degradation of alpha(s1)-casein occurred and that beta-casein was more resistant to hydrolysis. The use of a starter culture significantly influenced the levels of 12% trichloroacetic acid-soluble nitrogen, 5% phosphotungstic acid-soluble nitrogen, free amino acids, total free fatty acids, and the peptide profiles (reverse phase-HPLC) of 70% (vol/vol) ethanol-soluble and insoluble fractions of the pH 4.6-soluble fraction of the cheeses. The levels of peptides in the cheeses increased during the ripening period. Principal component and hierarchical cluster analyses of electrophoretic and chromatographic results indicated that the cheeses were significantly different in terms of their peptide profiles and they were grouped based on the use and type of starter and stage of ripening. Levels of free amino acid in the cheeses differed; Leu, Glu, Phe, Lys, and Val were the most abundant amino acids. Nitrogen fractions, total free amino acids, total free fatty acids, and the levels of peptides resolved by reverse phase-HPLC increased during ripening. No significant differences were found between the sensory properties of cheeses made using a starter, but the cheese made without starter received lower scores than the cheeses made using a starter. It was found that the cheese made with strains NCDO763 plus SK11 had the best quality during ripening. It was concluded that the use of different starter bacteria caused significant differences in the quality of the cheese, and that each starter culture contributed to proteolysis to a different degree.

pH-Dependent Solubility and Dissolution Behavior of Carvedilol--Case Example of a Weakly Basic BCS Class II Drug.

PubMed

Hamed, Rania; Awadallah, Areeg; Sunoqrot, Suhair; Tarawneh, Ola; Nazzal, Sami; AlBaraghthi, Tamadur; Al Sayyad, Jihan; Abbas, Aiman

2016-04-01

The objective of this study was to investigate the pH-dependent solubility and dissolution of weakly basic Biopharmaceutical Classification Systems (BCS) class II drugs, characterized by low solubility and high permeability, using carvedilol, a weak base with a pK a value of 7.8, as a model drug. A series of solubility and in vitro dissolution studies was carried out using media that simulate the gastric and intestinal fluids and cover the physiological pH range of the GI from 1.2 to 7.8. The effect of ionic strength, buffer capacity, and buffer species of the dissolution media on the solubility and dissolution behavior of carvedilol was also investigated. The study revealed that carvedilol exhibited a typical weak base pH-dependent solubility profile with a high solubility at low pH (545.1-2591.4 μg/mL within the pH range 1.2-5.0) and low solubility at high pH (5.8-51.9 μg/mL within the pH range 6.5-7.8). The dissolution behavior of carvedilol was consistent with the solubility results, where carvedilol release was complete (95.8-98.2% released within 60 min) in media simulating the gastric fluid (pH 1.2-5.0) and relatively low (15.9-86.2% released within 240 min) in media simulating the intestinal fluid (pH 6.5-7.8). It was found that the buffer species of the dissolution media may influence the solubility and consequently the percentage of carvedilol released by forming carvedilol salts of varying solubilities. Carvedilol solubility and dissolution decreased with increasing ionic strength, while lowering the buffer capacity resulted in a decrease in carvedilol solubility and dissolution rate.

Synergistic enhancement in the co-gelation of salt-soluble pea proteins and whey proteins.

PubMed

Wong, Douglas; Vasanthan, Thava; Ozimek, Lech

2013-12-15

This paper investigated the enhancement of thermal gelation properties when salt-soluble pea proteins were co-gelated with whey proteins in NaCl solutions, using different blend ratios, total protein concentrations, pH, and salt concentrations. Results showed that the thermal co-gelation of pea/whey proteins blended in ratio of 2:8 in NaCl solutions showed synergistic enhancement in storage modulus, gel hardness, paste viscosity and minimum gelation concentrations. The highest synergistic enhancement was observed at pH 6.0 as compared with pH 4.0 and 8.0, and at the lower total protein concentration of 10% as compared with 16% and 22% (w/v), as well as in lower NaCl concentrations of 0.5% and 1.0% as compared with 1.5%, 2.0%, 2.5%, and 3.0% (w/v). The least gelation concentrations were also lower in the different pea/whey protein blend ratios than in pure pea or whey proteins, when dissolved in 1.0% or 2.5% (w/v) NaCl aqueous solutions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Whey-grape juice drink processed by supercritical carbon dioxide technology: Physicochemical characteristics, bioactive compounds and volatile profile.

PubMed

Amaral, Gabriela V; Silva, Eric Keven; Cavalcanti, Rodrigo N; Martins, Carolina P C; Andrade, Luiz Guilherme Z S; Moraes, Jeremias; Alvarenga, Verônica O; Guimarães, Jonas T; Esmerino, Erick A; Freitas, Mônica Q; Silva, Márcia C; Raices, Renata S L; Sant' Ana, Anderson S; Meireles, M Angela A; Cruz, Adriano G

2018-01-15

The effect of supercritical carbon dioxide technology (SCCD, 14, 16, and 18MPa at 35±2°C for 10min) on whey-grape juice drink characteristics was investigated. Physicochemical characterization (pH, titratable acidity, total soluble solids), bioactive compounds (phenolic compounds, anthocyanin, DPPH and ACE activity) and the volatile compounds were performed. Absence of differences were found among treatments for pH, titratable acidity, soluble solids, total anthocyanin and DPPH activity (p-value>0.05). A direct relationship between SCCD pressure and ACE inhibitory activity was observed, with 34.63, 38.75, and 44.31% (14, 16, and 18MPa, respectively). Regards the volatile compounds, it was noted few differences except by the presence of ketones. The findings confirm the SCCD processing as a potential promising technology to the conventional thermal treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biochemical changes in some deciduous tree species around Talcher thermal power station, Odisha, India.

PubMed

Nayak, Rekha; Biswal, Debasis; Sett, Rupnarayan

2013-05-01

The present study was conducted to evaluate biochemical traits in leaves to assess the air pollution impact on plants caused by thermal power plant emissions. Ten species of deciduous trees were selected from study sites in different seasons. pH, chlorophyll, phenols, total soluble sugar content and proline content in fresh leaf was analyzed. The leaf wash pH content reveals moderately acidic (4.5-5.0) to highly acidic (3.5-4.5) range. Significant differences (p < 0.01) were observed in chlorophyll content according to the seasons and sites. Maximum reduction in chlorophyll was noticed at 2.5 km and 5.0 km west from the power plant. Greater reduction in chloropohyll 'b' than chlorophyll 'a' was noticed. An increase in total soluble sugars and phenols was observed at sites closer to thermal power plant in comparison to control. Highest concentration of total phenols was found in summer season in Dalbergia sissoo (1.52%), Butea monosperma (1.12%), Mangifera indica (1.2%), Tectona grandis (1.26%) and Acacia leucophloea (1.16%) at 2.5 km north from the source. Highest concentration of soluble sugar was found in Dalbergia sissoo (7.75%) during winter season. There was about 10-20 fold increase in proline content of leaves in comparison to the control.

Soluble organic carbon and pH of organic amendments affect metal mobility and chemical speciation in mine soils.

PubMed

Pérez-Esteban, Javier; Escolástico, Consuelo; Masaguer, Alberto; Vargas, Carmen; Moliner, Ana

2014-05-01

We evaluated the effects of pH and soluble organic carbon affected by organic amendments on metal mobility to find out the optimal conditions for their application in the stabilization of metals in mine soils. Soil samples (pH 5.5-6.2) were mixed with 0, 30 and 60 th a(-1) of sheep-horse manure (pH 9.4) and pine bark compost (pH 5.7). A single-step extraction procedure was performed using 0.005 M CaCl2 adjusted to pH 4.0-7.0 and metal speciation in soil solution was simulated using NICA-Donnan model. Sheep-horse manure reduced exchangeable metal concentrations (up to 71% Cu, 75% Zn) due to its high pH and degree of maturity, whereas pine bark increased them (32% Cu, 33% Zn). However, at increasing dose and hence pH, sheep-horse manure increased soluble Cu because of higher soluble organic carbon, whereas soluble Cu and organic carbon increased at increasing dose and correspondingly decreasing pH in pine bark and non-amended treatments. Near the native pH of these soils (at pH 5.8-6.3), with small doses of amendments, there was minimum soluble Cu and organic carbon. Pine bark also increased Zn solubility, whereas sheep-horse manure reduced it as soluble Zn always decreased with increasing pH. Sheep-horse manure also reduced the proportion of free metals in soil solution (from 41% to 4% Cu, from 97% to 94% Zn), which are considered to be more bioavailable than organic species. Sheep-horse manure amendment could be efficiently used for the stabilization of metals with low risk of leaching to groundwater at low doses and at relatively low pH, such as the native pH of mine soils. Copyright © 2013 Elsevier Ltd. All rights reserved.

Distribution of Cd, Pb, Zn and Cu and their chemical speciations in soils from a peri-smelter area in northeast China

NASA Astrophysics Data System (ADS)

Du, Ping; Xue, Nandong; Liu, Li; Li, Fasheng

2008-07-01

An exploratory study on soil contamination of heavy metals was carried out surrounding Huludao zinc smelter in Liaoning province, China. The distribution of total heavy metals and their chemical speciations were investigated. The correlations between heavy metal speciations and soil pH values in corresponding sites were also analyzed. In general, Cd, Zn, Pb, Cu and As presented a significant contamination in the area near the smelter, comparied with Environmental Quality Standards for Soils in China. The geoaccumulation index showed the degree of contamination: Cd > Zn > Pb > Cu > As. There was no obvious pollution of Cr and Ni in the studied area. The speciation analysis showed that the dominant fraction of Cd and Zn was the acid soluble fraction, and the second was the residual fraction. Pb was mostly associated with the residual fraction, which constituted more than 50% of total concentration in all samples. Cu in residual fraction accounted for a high percentage (40-80%) of total concentration, and the proportion of Cu in the oxidizable fraction is higher than that of other metals. The distribution pattern of Pb and Zn was obviously affected by soil pH. It seemed that Pb and Zn content in acid solution fraction increased with increasing soil pH values, while Cd content in acid soluble fraction accounted for more proportion in neutral and alkaline groups than acidic one. The fraction distribution patterns of Cu in three pH groups were very similar and independent of soil pH values. And the residual fraction of Cu took a predominant part (50%) of the total content.

The "high solubility" definition of the current FDA Guidance on Biopharmaceutical Classification System may be too strict for acidic drugs.

PubMed

Yazdanian, Mehran; Briggs, Katherine; Jankovsky, Corinne; Hawi, Amale

2004-02-01

The purpose of this study was to assess if the definition of high solubility as proposed in the FDA Guidance on Biopharmaceutical Classification System (BCS) is too strict for highly permeable acidic drugs. The solubility and permeability values of 20 (18 acidic and 2 non-acidic) nonsteroidal anti-inflammatory drugs (NSAID) were determined. The NSAIDs were grouped into three different sets having acetic acid, propionic acid, or other acidic moieties such as fenamate, oxicam, and salicylate. Two nonacidic NSAIDs (celecoxib and rofecoxib) were also included for comparison purposes. Equilibrium solubility values were determined at pH 1.2, 5.0, 7.4, and in biorelevant media simulating fed intestinal fluid at pH 5.0. For a select number of acids, we also measured solubility values in media simulating gastric and fasted intestinal fluids. Permeability classification was established relative to that of reference drugs in the Caco-2 cell permeability model. Permeability coefficients for all drugs were measured at concentrations corresponding to the lowest and highest marketed dose strengths dissolved in 250 ml volume, and their potential interaction with cellular efflux pumps was investigated. All NSAIDs with different acidic functional groups were classified as highly permeable based on their Caco-2 cell permeability. Only ketorolac appeared to have a potential for interaction with cellular efflux pumps. Solubility classification was based on comparison of equilibrium solubility at pH 1.2, 5.0. and 7.4 relative to marketed dose strengths in 250 ml. The pKa values for the acidic NSAIDs studied were between 3.5 and 5.1. and, as expected, their solubility increased dramatically at pH 7.4 compared to pH 1.2. Only three NSAIDs, ketorolac, ketoprofen. and acetyl salicylic acid, meet the current criteria for high solubility over the entire pH range. However, with the exception of ibuprofen, oxaprozin, and mefenamic acid, the remaining compounds can be classified as Class I drugs (high solubility-high permeability) relative to solubility at pH 7.4. The use of bio-relevant media simulating gastric and intestinal milieu for solubility measurements or increasing the dose volume to 500 ml did not provide for a better boundary for solubility classification. Based on the current definition of solubility, 15 of the 18 acidic NSAIDs in this study will be classified as Class II compounds as the solubility criteria applies to the entire pH range of 1.2 to 7.4, although the low solubility criteria does not hold true over the entire pH range. Whence, of the 18 acidic drugs, 15 can be classified as Class I based on the pH 7.4 solubility alone. This finding is intriguing because these drugs exhibit Class I behavior as their absorption does not seem to be dissolution or solubility limited. It could then be argued that for acidic drugs, the boundaries for solubility are too restrictive. Solubility at pH > 5 (pH in duodenum) may be more appropriate because most compounds are mainly absorbed in the intestinal region. Consideration for an intermediate solubility classification for highly permeable ionizable compounds that reflects physiological conditions seems warranted.

Water soluble folate-chitosan nanogels crosslinked by genipin.

PubMed

Pujana, Maite Arteche; Pérez-Álvarez, Leyre; Iturbe, L Carlos Cesteros; Katime, Issa

2014-01-30

Folate-chitosan conjugates were prepared by a concurrent functionalization and crosslinking reaction with the natural crosslinker genipin. Genipin molecule was employed simultaneously as crosslinker agent and spacer molecule in order to allow the functionalization with folic acid for active tumor targeting. The reaction was carried out in reverse microemulsion which provided colloidal size and monodisperse particle size distribution. The water solubility of the obtained folate-genipin-chitosan nanogels was studied as function of the pH of the medium and all nanoparticles were totally dispersible at physiological pH. The enzymatic degradability of the nanogels in a lysozyme solution was evaluated at acidic and physiological pH. QELS analyses of the swelling behavior of the nanogels with the pH did not show a clear pH-sensitivity. However, the study on the loading and release capacity of 5-fluorouracil revealed an interesting pH-responsive behavior of the nanogels that makes them promising as nanodevices for targeted anticancer drug delivery. Copyright © 2013 Elsevier Ltd. All rights reserved.

THE EFFECT OF FLUORIDE ON LEAD SOLUBILITY

EPA Science Inventory

Difficulties in predicting and controlling lead corrosion are encountered by hundreds of water systems across the country. Inorganic carbonate, sulfate, silicate, orthophosphate, pH, total organic carbon, temperature and the type/amount of chlorine residual are all known factors ...

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 weakened due to the dispersion caused by dynamic land/sea breeze on the coast.

Effect of digestion temperature and pH on treatment efficiency and evolution of volatile fatty acids during thermophilic aerobic digestion of model high strength agricultural waste.

PubMed

Ugwuanyi, J Obeta; Harvey, L M; McNeil, B

2005-04-01

Thermophilic aerobic digestion (TAD) of a model agricultural waste, potato peel slurry, at soluble chemical oxygen demand (COD) load equivalent to approximately 8.0 gl(-1), was carried out under batch conditions at 0.5 vvm aeration rate. Digestions were carried out at temperatures of 45, 50, 55, 60 and 65 degrees C (or left unregulated) without pH control to study the effect of digestion temperatures on TAD. The effects of digestion pH on the process were studied at pH 6.0, 7.0, 8.0, 9.0 and 9.5 (and in unregulated control) all at 55 degrees C. Except for digestion at 65 degrees C, which was inoculated extraneously using culture of Bacillus strearothermophilus all reactions were carried out using the populations indigenous to the waste. During digestion at different temperatures, the removal of soluble COD increased with temperature to reach a peak at 60 degrees C before declining slightly, removal of soluble solid (SS) followed similar pattern and reached peak at 65 degrees C being the highest temperature studied, while the degradation of TSS and TS (TSS + TS) decreased with an increase in temperature. Digestion at pH 7.0 was more efficient than at other pH values. Acetate was the predominant volatile fatty acid (VFA) in all the reactions and accounted for up to 90% of the total. Digestion at 60 degrees C led to the greatest accumulation of acetate, and this coincided with the period of highest oxygen uptake, and rapid consumption of soluble carbohydrate. Iso-valerate was also produced at all pH values. Digestion at 55 degrees C and also at pH 7.0 led to rapid and efficient processes with least accumulation of VFA and should be of interest in full-scale processes whenever it is practicable to regulate the digestion pH and temperature. The result of digestion at unregulated pH indicates that gradual adaptation may be used to achieve efficient treatment at elevated pH values. This would be of interest in full-scale processes where it is not practicable to tightly regulate digestion pH, and where the waste is produced at a pH value much higher than neutral.

New recommendations for measuring collagen solubility.

PubMed

Latorre, María E; Lifschitz, Adrian L; Purslow, Peter P

2016-08-01

The heat-solubility of intramuscular collagen is usually conducted in 1/4 Ringer's solution at pH7.4, despite this ionic strength and pH being inappropriate for post-rigor meat. The current work studied the percentage of soluble collagen and hydrothermal isometric tension characteristics of perimysial strips on bovine semitendinosus muscles in either 1/4 Ringer's solution, distilled water, PBS, or a solution of the same salt concentration as 1/4 Ringer's but at pH5.6. Values of % soluble collagen were lower at pH7.4 than 5.6. Increasing ionic strength reduced % soluble collagen. The maximum perimysial isometric tension was independent of the bathing medium, but the percent relaxation was higher at pH7.4 than at pH5.6, and increased with ionic strength of the media. It is recommended that future measurements of collagen solubility and tests on connective tissue components of post-rigor meat should be carried out in a solution of concentrations NaCl and KCl equivalent to those in 1/4 Ringer's, but at pH5.6, a pH relevant to post-rigor meat. Copyright © 2016 Elsevier Ltd. All rights reserved.

Expression and Characterization of Acidothermus celluloyticus E1 Endoglucanase in Transgenic Duckweed Lemna minor 8627

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Y.; Cheng, J. J.; Himmel, M. E.

2007-01-01

Endoglucanase E1 from Acidothermus cellulolyticus was expressed cytosolically under control of the cauliflower mosaic virus 35S promoter in transgenic duckweed, Lemna minor 8627 without any obvious observable phenotypic effects on morphology or rate of growth. The recombinant enzyme co-migrated with the purified catalytic domain fraction of the native E1 protein on western blot analysis, revealing that the cellulose-binding domain was cleaved near or in the linker region. The duckweed-expressed enzyme was biologically active and the expression level was up to 0.24% of total soluble protein. The endoglucanase activity with carboxymethylcellulose averaged 0.2 units mg protein{sup -1} extracted from fresh duckweed.more » The optimal temperature and pH for E1 enzyme activity were about 80 C and pH 5, respectively. While extraction with HEPES (N-[2-hydroxyethyl]piperazine-N{prime}-[2-ethanesulfonic acid]) buffer (pH 8) resulted in the highest recovery of total soluble proteins and E1 enzyme, extraction with citrate buffer (pH 4.8) at 65 C enriched relative amounts of E1 enzyme in the extract. This study demonstrates that duckweed may offer new options for the expression of cellulolytic enzymes in transgenic plants.« less

Solubility and dissolution improvement of ketoprofen by emulsification ionic gelation

NASA Astrophysics Data System (ADS)

Rachmaniar, Revika; Tristiyanti, Deby; Hamdani, Syarif; Afifah

2018-02-01

Ketoprofen or [2-(3-benzoylphenyl) propionic acid] is non-steroidal anti-inflammatory (NSAID) and an analgesic which has high permeability and low solubility. The purpose of this work was to improve the solubility and dissolution of poorly water-soluble ketoprofen prepared by emulsification ionic gelation method and utilizing polymer (chitosan) and cross linker (tripolyphosphate, TPP) for particles formulation. The results show that increasing pH value of TPP, higher solubility and dissolution of as-prepared ketoprofen-chitosan was obtained. The solubility in water of ketoprofen-chitosan with pH 6 for TPP increased 2.71-fold compared to untreated ketoprofen. While the dissolution of ketoprofen-chitosan with pH 6 of TPP in simulated gastric fluid without enzyme (0.1 N HCl), pH 4.5 buffer and simulated intestinal fluid without enzyme (phosphate buffer pH 6.8) was increased 1.9-fold, 1.6-fold and 1.2-fold compared to untreated ketoprofen for dissolution time of 30 minutes, respectively. It could be concluded that chitosan and TPP in the emulsification ionic gelation method for ketoprofen preparation effectively increases solubility and dissolution of poorly water-soluble ketoprofen.

Effect of fermentation and sterilization on anthocyanins in blueberry.

PubMed

Nie, Qixing; Feng, Lei; Hu, Jielun; Wang, Sunan; Chen, Haihong; Huang, Xiaojun; Nie, Shaoping; Xiong, Tao; Xie, Mingyong

2017-03-01

Blueberry products have various health benefits due to their high content of dietary anthocyanins. The aim of this study was to investigate the impact of fermentation and sterilization on total anthocyanin content, composition and some quality attributes of blueberry puree. The blueberry puree used here was fermented for 40 h at 37 °C by Lactobacillus after sterilization. The method of ultra-performance liquid chromatography-mass spectrometry was optimized for the rapid analysis of anthocyanins. Quality attributes including pH, color, total soluble solids and viscosity were measured. A total of 21 anthocyanins and five anthocyanidins were quantified by ultra-performance liquid chromatography. Fermented blueberry had reduced total anthocyanin content (29%) and levels of individual anthocyanins compared with fresh blueberry. Total anthocyanin content was decreased 46% by sterilization, and different degradation behavior of individual anthocyanin was appeared between fermented and sterilized-fermented blueberry puree. Fermentation and sterilization decreased the total soluble solids and pH and changed color parameters, while minimally influencing viscosity. The loss of total anthocyanin content by fermentation was related to the unstable structure of blueberry anthocyanins. Anthocyanins are sensitive to temperature (>80 °C), and degradation of anthocyanins by sterilization in blueberry should be considered in the fermentation procedure. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Dissolution and solubility behavior of fenofibrate in sodium lauryl sulfate solutions.

PubMed

Granero, Gladys E; Ramachandran, Chandrasekharan; Amidon, Gordon L

2005-10-01

The solubility of fenofibrate in pH 6.8 McIlvaine buffers containing varying concentrations of sodium lauryl sulfate was determined. The dissolution behavior of fenofibrate was also examined in the same solutions with rotating disk experiments. It was observed that the enhancement in intrinsic dissolution rate was approximately 500-fold and the enhancement in solubility was approximately 2000-fold in a pH 6.8 buffer containing 2% (w/v) sodium lauryl sulfate compared to that in buffer alone. The micellar solubilization equilibrium coefficient (k*) was estimated from the solubility data and found to be 30884+/-213 L/mol. The diffusivity for the free solute, 7.15x10(-6) cm2/s, was calculated using Schroeder's additive molal volume estimates and Hayduk-Laurie correlation. The diffusivity of the drug-loaded micelle, estimated from the experimental solubility and dissolution data and the calculated value for free solute diffusivity, was 0.86x10(-6) cm2/s. Thus, the much lower enhancement in dissolution of fenofibrate compared to its enhancement in solubility in surfactant solutions appears to be consistent with the contribution to the total transport due to enhanced micellar solubilization as well as a large decrease (approximately 8-fold) in the diffusivity of the drug-loaded micelle.

Effect of aeration rate and waste load on evolution of volatile fatty acids and waste stabilization during thermophilic aerobic digestion of a model high strength agricultural waste.

PubMed

Ugwuanyi, J Obeta; Harvey, L M; McNeil, B

2005-04-01

Thermophilic aerobic digestion (TAD) is a relatively new, dynamic and versatile low technology for the economic processing of high strength waste slurries. Waste so treated may be safely disposed of or reused. In this work a model high strength agricultural waste, potato peel, was subjected to TAD to study the effects of oxygen supply at 0.1, 0.25, 0.5 and 1.0 vvm (volume air per volume slurry per minute) under batch conditions at 55 degrees C for 156 h on the process. Process pH was controlled at 7.0 or left unregulated. Effects of waste load, as soluble chemical oxygen demand (COD), on TAD were studied at 4.0, 8.0, 12.0 and 16.0 gl(-1) (soluble COD) at pH 7.0, 0.5 vvm and 55 degrees C. Efficiency of treatment, as degradation of total solids, total suspended solids and soluble solid, as well as soluble COD significantly increased with aeration rate, while acetate production increased as the aeration rate decreased or waste load increased, signifying deterioration in treatment. Negligible acetate, and no other acids were produced at 1.0 vvm. Production of propionate and other acids increased after acetate concentration had started to decrease and, during unregulated reactions coincided with the drop in the pH of the slurry. Acetate production was more closely associated with periods of oxygen limitation than were other acids. Reduction in oxygen availability led to deterioration in treatment efficiency as did increase in waste load. These variables may be manipulated to control treated waste quality.

Calcium phosphates recovery from digester supernatant by fast precipitation and recrystallization

NASA Astrophysics Data System (ADS)

Vasenko, Liubov; Qu, Haiyan

2018-01-01

Conditional solubility of dicalcium phosphate dihydrate (DCPD) and hydroxyapatite (HAp) in digester supernatant was determined as a function of pH and was compared to its conditional solubility in distilled water. Conditional solubility of both substances in digester supernatant at pH >5-6 was higher than their conditional solubility in pure water due to the presence of impurities, and this influence is more significant for HAp. Amorphous CaP was precipitated through a fast precipitation process from digester supernatant with initial total phosphate concentration 0.008 mol/L and 0.015 mol/L and Ca/P ratios 2 and 5. The amorphous CaP can be subsequently recrystallized into crystalline CaP. Obtained amorphous products have Ca/P ratio > 1, which allow performing the recrystallization process without further Ca dosing into the system. Batch recrystallization of the amorphous products resulted in crystallization of HAp, DCPD or their mixture depending on the conditions of the process. Maximum achieved P-recovery was 69.5%. The increase of phosphate concentration and the addition of seeding decreased the yield of the process but promoted crystallization of DCPD. The increase of Ca/P ratio had a positive effect on the total P-recovery. Compared with the direct batch crystallization of CaP from digester supernatant, the two-step process with fast precipitation and recrystallization significantly improved the color of the obtained products.

Acceptability and solubility of iron and zinc contents of modified Moringa oleifera sauces consumed in the Far-north region of Cameroon.

PubMed

Mawouma, Saliou; Ponka, Roger; Mbofung, Carl Moses

2017-03-01

Consumption of Moringa oleifera leaves is a local and inexpensive solution to iron and zinc deficiencies in the Far-north region of Cameroon. However, traditional household's cooking techniques result in sauces with high pH levels and low leaves incorporation rates that compromise the bioavailability of iron and zinc. The aim of our study was to investigate the effect of modifying a standard Moringa sauce on consumer acceptability and the solubility of iron and zinc, which is an indicator of their bioavailability. Lime juice or tamarind pulp was added to a standard recipe in order to reduce the pH by about one unit, and Moringa leaf powder was incorporated in each acidulated sauce at three levels (1, 2, and 4 g/100 g of sauce). All the formulations were evaluated for their acceptability by 30 housewives using a five-point hedonic scale. The pH was measured by a digital electronic pH-meter. Moisture and ash were determined by AOAC methods. Total iron and zinc contents were determined by atomic absorption spectrophotometry, and soluble iron and zinc by HCl-extractability. The lime juice-acidulated sauce and the tamarind pulp-acidulated sauce enriched with 1 g of Moringa leaf powder were the most acceptable formulations with scores of 3.4 and 3.6, respectively. Their chemical analysis showed a reduced pH (6.4 and 6.1, respectively), compared to the Control (7.2). Lime juice-acidulated sauce improved iron and zinc solubility from 42.19 to 66.38% and 54.03 to 82.03%, respectively. Tamarind pulp-acidulated sauce enriched with 1 g of Moringa leaf powder showed a decrease in iron solubility from 42.19 to 38.26% and an increase in zinc solubility from 54.03 to 72.86%. These results confirm the beneficial effect of lime juice in improving iron and zinc bioavailability.

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.

How cocrystals of weakly basic drugs and acidic coformers might modulate solubility and stability.

PubMed

Kuminek, G; Rodríguez-Hornedo, N; Siedler, S; Rocha, H V A; Cuffini, S L; Cardoso, S G

2016-04-30

Cocrystals of a weakly basic drug (nevirapine) with acidic coformers are shown to alter the solubility dependence on pH, and to exhibit a pHmax above which a less soluble cocrystal becomes more soluble than the drug. The cocrystal solubility advantage can be dialed up or down by solution pH.

Predicting the solubility and lability of Zn, Cd, and Pb in soils from a minespoil-contaminated catchment by stable isotopic exchange

NASA Astrophysics Data System (ADS)

Marzouk, E. R.; Chenery, S. R.; Young, S. D.

2013-12-01

The Rookhope catchment of Weardale, England, has a diverse legacy of contaminated soils due to extensive lead mining activity over four centuries. We measured the isotopically exchangeable content of Pb, Cd and Zn (E-values) in a large representative subset of the catchment soils (n = 246) using stable isotope dilution. All three metals displayed a wide range of %E-values (c. 1-100%) but relative lability followed the sequence Cd > Pb > Zn. A refinement of the stable isotope dilution approach also enabled detection of non-reactive metal contained within suspended sub-micron (<0.22 μm) colloidal particles (SCP-metal). For most soils, the presence of non-labile SCP-metal caused only minor over-estimation of E-values (<2%) but the effect was greater for soils with particularly large humus or carbonate contents. Approximately 80%, 53% and 66% of the variability in Zn, Cd and Pb %E-values (respectively) could be explained by pH, loss on ignition and total metal content. E-values were affected by the presence of ore minerals at high metal contents leading to an inconsistent trend in the relationship between %E-value and soil metal concentration. Metal solubility, in the soil suspensions used to measure E-values, was predicted using the WHAM geochemical speciation model (versions VI and VII). The use of total and isotopically exchangeable metal as alternative input variables was compared; the latter provided significantly better predictions of solubility, especially in the case of Zn. Lead solubility was less well predicted by either version of WHAM, with over-prediction at low pH and under-prediction at high soil pH values. Quantify the isotopically exchangeable fractions of Zn, Cd and Pb (E-values), and assess their local and regional variability, using multi-element stable isotope dilution, in a diverse range of soil ecosystems within the catchment of an old Pb/Zn mining area. Assess the controlling influences of soil properties on metal lability and develop predictive algorithms for metal lability in the contaminated catchment based on simple soil properties (such as pH, organic matter (LOI), and total metal content). Examine the incidence of non-isotopically-exchangeable metal held within suspended colloidal particles (SCP-metal) in filtered soil solutions (<0.22 μm) by comparing E-values from isotopic abundance in solutions equilibrated with soil and in a resin phase equilibrated with the separated solution. Assess the ability of a geochemical speciation model, WHAM(VII), to predict metal solubility using isotopically exchangeable metal as an input variable.

Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof

DOE PAGES

Du Preez, S. P.; Beukes, J. P.; Van Dalen, W. P. J.; ...

2017-04-21

The production of ferrochrome (FeCr) is a reducing process. However, it is impossible to completely exclude oxygen from all of the high-temperature production process steps, which may lead to unintentional formation of small amounts of Cr(VI). The majority of Cr(VI) is associated with particles found in the off-gas of the high-temperature processes, which are cleaned by means of venturi scrubbers or bag filter dust (BFD) systems. BFD contains the highest concentration of Cr(VI) of all FeCr wastes. In this study, the solubility of Cr(VI) present in BFD was determined by evaluating four different BFD samples. The results indicate that themore » currently applied Cr(VI) treatment strategies of the FeCr producer (with process water pH ≤ 9) only effectively extract and treat the water-soluble Cr(VI) compounds, which merely represented approximately 31% of the total Cr(VI) present in the BFD samples evaluated. Extended extraction time, within the afore-mentioned pH range, proved futile in extracting sparingly-soluble and water-insoluble Cr(VI) species, which represented approximately 34% and 35% of the total Cr(VI), respectively. Due to the deficiencies of the current treatment strategies, it is highly likely that sparingly water-soluble Cr(VI) compounds will leach from waste storage facilities (e.g. slimes dams) over time. Therefore, it is critical that improved Cr(VI) treatment strategies be formulated, which should be an important future perspective for FeCr producers and researchers alike.« less

How cocrystals of weakly basic drugs and acidic coformers might modulate solubility and stability

PubMed Central

Kuminek, G.; Rodríguez-Hornedo, N.; Siedler, S.; Rocha, H. V. A.; Cuffini, S. L.; Cardoso, S. G.

2016-01-01

Cocrystals of a weakly basic drug (nevirapine) with acidic coformers are shown to alter the solubility dependence on pH, and to exhibit a pHmax above which a less soluble cocrystal becomes more soluble than the drug. The cocrystal solubility advantage can be dialed up or down by solution pH. PMID:27042997

Hydrothermal ore-forming processes in the light of studies in rock- buffered systems: II. Some general geologic applications

USGS Publications Warehouse

Hemley, J.J.; Hunt, J.P.

1992-01-01

The experimental metal solubilities for rock-buffered hydrothermal systems provide important insights into the acquisition, transport, and deposition of metals in real hydrothermal systems that produced base metal ore deposits. Water-rock reactions that determine pH, together with total chloride and changes in temperature and fluid pressure, play significant roles in controlling the solubility of metals and determining where metals are fixed to form ore deposits. Deposition of metals in hydrothermal systems occurs where changes such as cooling, pH increase due to rock alteration, boiling, or fluid mixing cause the aqueous metal concentration to exceed saturation. Metal zoning results from deposition occurring at successive saturation surfaces. Zoning is not a reflection simply of relative solubility but of the manner of intersection of transport concentration paths with those surfaces. Saturation surfaces will tend to migrate outward and inward in prograde and retrograde time, respectively, controlled by either temperature or chemical variables. -from Authors

[Dissolved aluminum and organic carbon in soil solution under six tree stands in Lushan forest ecosystems].

PubMed

Wang, Lianfeng; Pan, Genxing; Shi, Shengli; Zhang, Lehua; Huang, Mingxing

2003-10-01

Different depths of soils under 6 tree stands in Lushan Botany Garden were sampled and water-digested at room temperature. The dissolved aluminum and organic carbon were then determined by colorimetry, using 8-hydroxylquilin and TOC Analyzer, respectively. The results indicated that even derived from a naturally identical soil type, the test soils exhibited a diverse solution chemistry, regarding with the Al speciation. The soil solutions under Japanese cedar, giant arborvitae and tea had lower pH values and higher contents of soluble aluminum than those under Giant dogwood, azalea and bamboo. Under giant arborvitae, the lowest pH and the highest content of total soluble aluminum and monomeric aluminum were found in soil solution. There was a significant correlation between soluble aluminum and DOC, which tended to depress the accumulation of toxic monomeric aluminum. The 6 tree stands could be grouped into 2 categories of solution chemistry, according to aluminum mobilization.

Physicochemical properties of valsartan and the effect of ethyl alcohol, propylene glycol and pH on its solubility.

PubMed

Mbah, C J

2005-11-01

The aqueous solubility and partition coefficient of valsartan were determined at room temperature. The effect of ethyl alcohol, propylene glycol and pH on its solubility was also investigated. It was found that both solvents increased the solubility of the drug in water. The solubilizing power of ethyl alcohol was found to be higher than that of propylene glycol. Valsartan solubility was also observed to increase at high pH values and its lipophilicity wasdemonstrated by the high positive value of the logarithm of partition coefficient.

Dissolution-modulating mechanism of pH modifiers in solid dispersion containing weakly acidic or basic drugs with poor water solubility.

PubMed

Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh; Lee, Kyoung-Ho; Kim, Dong-Jin; Lee, Beom-Jin

2010-05-01

Although the solid dispersion method has been known to increase the dissolution rate of poorly water-soluble drugs by dispersing them in hydrophilic carriers, one obstacle of the solid dispersion method is its limited solubilization capacity, especially for pH-dependent soluble drugs. pH-modified solid dispersion, in which pH modifiers are incorporated, may be a useful method for increasing the dissolution rate of weakly acidic or basic drugs. Sufficient research, including the most recent reports, was undertaken in this review. How could the inclusion of the pH the pH modifiers in the solid dispersion system change drug structural behaviors, molecular interactions, microenvironmental pH, and/or release rate of pH modifiers, relating with the enhanced dissolution of weakly acidic or weakly basic drugs with poor water solubility? These questions have been investigated to determine the dissolution-modulating mechanism of pH modifiers in solid dispersion containing weakly acidic or basic drugs. It is believed that step-by-step mechanistic approaches could provide the ultimate solution for solubilizing several poorly water-soluble drugs with pH-dependent solubility from a solid dispersion system, as well as provide ideas for developing future dosage systems.

In vitro Solubility of Copper(II) Sulfate and Dicopper Chloride Trihydroxide for Pigs.

PubMed

Park, C S; Kim, B G

2016-11-01

This study was conducted to determine the solubility of copper (Cu) in two sources of copper(II) sulfate (CuSO 4 ) including monohydrate and pentahydrate and three sources of dicopper chloride trihydroxide (dCCTH) including α-form (dCCTH-α), β-form (dCCTH-β), and a mixture of α- and β-form (dCCTH-αβ) at different pH and a 3-step in vitro digestion assay for pigs. In Exp. 1, Cu sources were incubated in water-based buffers at pH 2.0, 3.0, 4.8, and 6.8 for 4 h using a shaking incubator at 39°C. The CuSO 4 sources were completely dissolved within 15 min except at pH 6.8. The solubility of Cu in dCCTH-α was greater (p<0.05) than dCCTH-β but was not different from dCCTH-αβ during 3-h incubation at pH 2.0 and during 2-h incubation at pH 3.0. At pH 4.8, there were no significant differences in solubility of Cu in dCCTH sources. Copper in dCCTH sources were non-soluble at pH 6.8. In Exp. 2, the solubility of Cu was determined during the 3-step in vitro digestion assay for pigs. All sources of Cu were completely dissolved in step 1 which simulated digestion in the stomach. In Exp. 3, the solubility of Cu in experimental diets including a control diet and diets containing 250 mg/kg of additional Cu from five Cu sources was determined during the in vitro digestion assay. The solubility of Cu in diets containing additional Cu sources were greater (p<0.05) than the control diet in step 1. In conclusion, the solubility of Cu was influenced by pH of digesta but was not different among sources based on the in vitro digestion assay.

In vitro Solubility of Copper(II) Sulfate and Dicopper Chloride Trihydroxide for Pigs

PubMed Central

Park, C. S.; Kim, B. G.

2016-01-01

This study was conducted to determine the solubility of copper (Cu) in two sources of copper(II) sulfate (CuSO4) including monohydrate and pentahydrate and three sources of dicopper chloride trihydroxide (dCCTH) including α-form (dCCTH-α), β-form (dCCTH-β), and a mixture of α- and β-form (dCCTH-αβ) at different pH and a 3-step in vitro digestion assay for pigs. In Exp. 1, Cu sources were incubated in water-based buffers at pH 2.0, 3.0, 4.8, and 6.8 for 4 h using a shaking incubator at 39°C. The CuSO4 sources were completely dissolved within 15 min except at pH 6.8. The solubility of Cu in dCCTH-α was greater (p<0.05) than dCCTH-β but was not different from dCCTH-αβ during 3-h incubation at pH 2.0 and during 2-h incubation at pH 3.0. At pH 4.8, there were no significant differences in solubility of Cu in dCCTH sources. Copper in dCCTH sources were non-soluble at pH 6.8. In Exp. 2, the solubility of Cu was determined during the 3-step in vitro digestion assay for pigs. All sources of Cu were completely dissolved in step 1 which simulated digestion in the stomach. In Exp. 3, the solubility of Cu in experimental diets including a control diet and diets containing 250 mg/kg of additional Cu from five Cu sources was determined during the in vitro digestion assay. The solubility of Cu in diets containing additional Cu sources were greater (p<0.05) than the control diet in step 1. In conclusion, the solubility of Cu was influenced by pH of digesta but was not different among sources based on the in vitro digestion assay. PMID:27456425

Adaptation to rhizosphere acidification is a necessary prerequisite for wheat (Triticum aestivum L.) seedling resistance to ammonium stress.

PubMed

Wang, Feng; Gao, Jingwen; Tian, Zhongwei; Liu, Yang; Abid, Muhammad; Jiang, Dong; Cao, Weixing; Dai, Tingbo

2016-11-01

Because soil acidification accompanies ammonium (NH 4 + ) stress, the tolerance of higher plants to ammonium is associated with their adaptation to root medium acidification. However, the underlying mechanisms of this adaptation have not been fully elucidated. The objective of this study was thus to elucidate the effect of rhizosphere pH on NH 4 + tolerance in different winter wheat cultivars (Triticum aestivum L.). Hydroponic experiments were carried out on two wheat cultivars: AK58 (an NH 4 + -sensitive cultivar) and XM25 (an NH 4 + -tolerant cultivar). Four pH levels resembling acidified (4.0, 5.0, 6.0 and 7.0) were tested and 5 mM NH 4 + nitrogen (AN) was used as a stress treatment, with 5 mM nitrate nitrogen used as a control. The addition of AN led to a severe reduction in biomass and an increase in free NH 4 + , amino acids, and the activities of glutamine synthetase (GS) and glutamate dehydrogenase (GDH) in the shoots and roots of the two wheat cultivars. Further decreases in growth medium pH led to further increases in free NH 4 + , but decreases in total amino acids and the activities of GS and NADH-dependent glutamate synthase (NADH-GDH). However, there was less of an increase in free NH 4 + and less of a reduction in the activities of GS and NADH-GDH in the cultivar XM25 compared with AK58. In addition, total soluble sugar content and the root-to-shoot soluble sugar ratio were also decreased by AN treatment, except in the shoots of XM25. Decreasing pH resulted in lower root-to-shoot soluble sugar ratios with greater reductions in the AK58 cultivar. These results indicate that wheat growth was inhibited significantly by the addition of NH 4 + combined with low pH. Low medium pH reduced the capacity for nitrogen assimilation and interrupted carbohydrate transport between the shoot and root. The NH 4 + -tolerant cultivar XM25 was better adapted to low rhizosphere pH due to its increased capacity for assimilating NH 4 + efficiently and thereby avoiding toxic levels of intracellular NH 4 + at low medium pH. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Precipitation and Solubility of Calcium Hydrogenurate Hexahydrate

PubMed Central

Babić-Ivančić, V.; Füredi-Milhofer, H.; Brničević, N.; Marković, M.

1992-01-01

Solid phases formed in the quaternary system: uric acid—calcium hydroxide —hydrochloric acid—water aged for 2 months at 310 K were studied to determine conditions for calcium hydrogenurate hexahydrate, Ca(C5H3N4O)2 · 6H2O precipitation. The precipitates were identified by chemical and thermogravimetric analyses, x-ray powder diffraction, infrared spectroscopy, light microscopy, and scanning electron microscopy. In the precipitation diagram the concentration region in which calcium hydrogenurate hexahydrate precipitated as a single solid phase was established. The solubility of calcium hydrogenurate hexahydrate was investigated in the pH range from 6.2 to 10.1 at different temperatures. The total soluble and ionic concentration of calcium (atomic absorption spectroscopy and Ca-selective electrode), total urate concentration (spectrophotometry), and pH were determined in equilibrated solutions. The data are presented in the form of tables and chemical potential diagrams. By using these data the thermodynamic solubility products of calcium hydrogenurate hexahydrate, Ks = a(Ca2+) · a2(C5H3N4O3−), were determined: pKs=10.12±0.07at288K,pKs=9.81±0.09at298K,pKs=9.28±0.04at310K,andpKs=9.01±0.03at318K.The formation of calcium hydrogenurate hexahydrate crystals in urinary tract of patients with pathologically high concentrations of calcium and urates (hypercalciuria and hyperuricosiuria) is possible. PMID:28053438

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du Preez, S. P.; Beukes, J. P.; Van Dalen, W. P. J.

The production of ferrochrome (FeCr) is a reducing process. However, it is impossible to completely exclude oxygen from all of the high-temperature production process steps, which may lead to unintentional formation of small amounts of Cr(VI). The majority of Cr(VI) is associated with particles found in the off-gas of the high-temperature processes, which are cleaned by means of venturi scrubbers or bag filter dust (BFD) systems. BFD contains the highest concentration of Cr(VI) of all FeCr wastes. In this study, the solubility of Cr(VI) present in BFD was determined by evaluating four different BFD samples. The results indicate that themore » currently applied Cr(VI) treatment strategies of the FeCr producer (with process water pH ≤ 9) only effectively extract and treat the water-soluble Cr(VI) compounds, which merely represented approximately 31% of the total Cr(VI) present in the BFD samples evaluated. Extended extraction time, within the afore-mentioned pH range, proved futile in extracting sparingly-soluble and water-insoluble Cr(VI) species, which represented approximately 34% and 35% of the total Cr(VI), respectively. Due to the deficiencies of the current treatment strategies, it is highly likely that sparingly water-soluble Cr(VI) compounds will leach from waste storage facilities (e.g. slimes dams) over time. Therefore, it is critical that improved Cr(VI) treatment strategies be formulated, which should be an important future perspective for FeCr producers and researchers alike.« less

Marination and Physicochemical Characteristics of Vacuum-aged Duck Breast Meat.

PubMed

Khan, Muhammad Issa; Lee, Hyun Jung; Kim, Hyun-Joo; Young, Hae In; Lee, Haelim; Jo, Cheorun

2016-11-01

We investigated marinade absorption and physicochemical characteristics of vacuum-aged duck breasts that were halved and individually vacuum-packed for chiller aging at 4°C for 14 d. One half was marinated for 0, 7, or 14 d, while the second half was used as a control. Marinade absorption, cooking loss, cooking yield, texture profile, pH, color, protein solubility, and thiobarbituric acid reactive substances (TBARS) values were evaluated, and protein sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed. Marinade absorption and pH did not vary significantly after 14 d of aging. Marination increased the pH, color (a* and b*) values, and cooking yield and reduced cooking loss. TBARS values significantly increased with aging time, but were significantly reduced by marination. Myofibril and total protein solubility increased with aging and marination, while SDS-PAGE showed protein degradation. Hence, aging and marination can be used simultaneously to improve physicochemical quality and cooking yield of vacuum-aged duck breast.

Assessment of solubilization characteristics of different surfactants for carvedilol phosphate as a function of pH.

PubMed

Chakraborty, Subhashis; Shukla, Dali; Jain, Achint; Mishra, Brahmeshwar; Singh, Sanjay

2009-07-15

The effect of surfactants on the solubility of a new phosphate salt of carvedilol was investigated at different biorelevent pH to evaluate their solubilization capacity. Solutions of different classes of surfactants viz., anionic-sodium dodecyl sulfate (SDS) and sodium taurocholate (STC), cationic-cetyltrimethylammonium bromide (CTAB) and non-ionic-Tween 80 (T80) were prepared in the concentration range of 5-35 mmol dm(-3) in buffer solutions of pH 1.2, 3.0, 4.5, 5.8, 6.8 and 7.2. The solubility data were used to calculate the solubilization characteristics viz. molar solubilization capacity, water micelle partition coefficient, free energy of solubilization and binding constant. Solubility enhancement in basic pH was in following order: CTAB>T80>SDS>STC. CTAB and T80 showed remarkable solubility enhancement in acidic pH as well. Among the anionic surfactants, solubility in acidic medium was retarded except at pH 1.2 in case of SDS. Cationic and non-ionic surfactants were found to be suitable for enhancing the solubility of CP which can be employed for maintaining the in vitro sink condition in the basic dissolution medium. While anionic surfactants showed solubility retardant behavior which may be exploited in increasing the drug entrapment efficiency of a colloidal drug delivery system formulated by emulsification technique.

Impact of pH and Total Soluble Solids on Enzyme Inactivation Kinetics during High Pressure Processing of Mango (Mangifera indica) Pulp.

PubMed

Kaushik, Neelima; Nadella, Tejaswi; Rao, P Srinivasa

2015-11-01

This study was undertaken with an aim to enhance the enzyme inactivation during high pressure processing (HPP) with pH and total soluble solids (TSS) as additional hurdles. Impact of mango pulp pH (3.5, 4.0, 4.5) and TSS (15, 20, 25 °Brix) variations on the inactivation of pectin methylesterase (PME), polyphenol oxidase (PPO), and peroxidase (POD) enzymes were studied during HPP at 400 to 600 MPa pressure (P), 40 to 70 °C temperature (T), and 6- to 20-min pressure-hold time (t). The enzyme inactivation (%) was modeled using second order polynomial equations with a good fit that revealed that all the enzymes were significantly affected by HPP. Response surface and contour models predicted the kinetic behavior of mango pulp enzymes adequately as indicated by the small error between predicted and experimental data. The predicted kinetics indicated that for a fixed P and T, higher pulse pressure effect and increased isobaric inactivation rates were possible at lower levels of pH and TSS. In contrast, at a fixed pH or TSS level, an increase in P or T led to enhanced inactivation rates, irrespective of the type of enzyme. PPO and POD were found to have similar barosensitivity, whereas PME was found to be most resistant to HPP. Furthermore, simultaneous variation in pH and TSS levels of mango pulp resulted in higher enzyme inactivation at lower pH and TSS during HPP, where the effect of pH was found to be predominant than TSS within the experimental domain. Exploration of additional hurdles such as pH, TSS, and temperature for enzyme inactivation during high pressure processing of fruits is useful from industrial point of view, as these parameters play key role in preservation process design. © 2015 Institute of Food Technologists®

Effect of Ginger Extract and Citric Acid on the Tenderness of Duck Breast Muscles

PubMed Central

2015-01-01

The objective of this study was to examine the effect of ginger extract (GE) combined with citric acid on the tenderness of duck breast muscles. Total six marinades were prepared with the combination of citric acid (0 and 0.3 M citric acid) and GE (0, 15, and 30%). Each marinade was sprayed on the surface of duck breasts (15 mL/100 g), and the samples were marinated for 72 h at 4℃. The pH and proteolytic activity of marinades were determined. After 72 h of marination, Warner Bratzler shear force (WBSF), myofibrillar fragmentation index (MFI), pH, cooking loss, moisture content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and protein solubility were evaluated. There was no significant (p>0.05) difference in moisture content or cooking loss among all samples. However, GE marination resulted in a significant (p<0.05) decrease in WBSF but a significant (p<0.05) increase in pH and MFI. In addition, total protein and myofibrillar protein solubility of GE-marinated duck breast muscles in both WOC (without citric acid) and WC (with citric acid) conditions were significantly (p<0.05) increased compared to non-GE-marinated duck breast muscles. SDS-PAGE showed an increase of protein degradation (MHC and actin) in WC condition compared to WOC condition. There was a marked actin reduction in GE-treated samples in WC. The tenderization effect of GE combined with citric acid may be attributed to various mechanisms such as increased MFI and myofibrillar protein solubility. PMID:26877631

Determining total phenolic content and total antioxidant capacity of loquat cultivars grown in Hatay.

PubMed

Polat, A Aytekin; Calişkan, Oğuzhan; Serçe, Sedat; Saraçoğlu, Onur; Kaya, Cemal; Ozgen, Mustafa

2010-01-01

Several fruit characteristics of five loquat (Eriobotrya japonica (Thunb.) Lindl.) cultivars/selections grown in Dörtyol, Hatay, Turkey were investigated in 2008. The cultivars/selections included 'Baduna 5', Güzelyurt 1, 'Hafif Cukurgöbek', 'Ottaviani,' and Type 1. The characteristics evaluated included fruit weight, width, length, seed number and weight, flesh/seed ratio, total soluble solids (TSS), pH, acidity, total phenolic (TP) content, and total antioxidant capacity (TAC), determined by the ferric reducing antioxidant power (FRAP) assay. The analyses were conducted by three replicates, with 30 fruits in each replicate. The results indicated that there were significant differences among the cultivars, for all the traits tested. For example, 'Hafif Cukurgöbek' and 'Ottaviani' had smaller fruits than others, although 'Hafif Cukurgöbek' had heavier seeds. The flesh/seed ratio was the highest in Type 1, while 'Hafif Cukurgöbek' had the highest pH and high soluble solids. 'Baduna 5' and 'Hafif Cukurgöbek' had the highest acidity. The TP ranged from 129 ('Baduna 5') to 578 ('Hafif Cukurgöbek') mg gallic acid equivalent (GAE)/kg fresh fruit (fw). 'Hafif Cukurgöbek' also had the highest FRAP mean (12.1 mmol Trolox Equivalent (TE)/kg fw). The results suggest that loquat cultivars have a variable range of TP content and a relatively high total antioxidant capacity, which is crucial for human health.

[Super sweet corn hybrids adaptability for industrial processing. I freezing].

PubMed

Alfonzo, Braunnier; Camacho, Candelario; Ortiz de Bertorelli, Ligia; De Venanzi, Frank

2002-09-01

With the purpose of evaluating adaptability to the freezing process of super sweet corn sh2 hybrids Krispy King, Victor and 324, 100 cobs of each type were frozen at -18 degrees C. After 120 days of storage, their chemical, microbiological and sensorial characteristics were compared with a sweet corn su. Industrial quality of the process of freezing and length and number of rows in cobs were also determined. Results revealed yields above 60% in frozen corns. Length and number of rows in cobs were acceptable. Most of the chemical characteristics of super sweet hybrids were not different from the sweet corn assayed at the 5% significance level. Moisture content and soluble solids of hybrid Victor, as well as total sugars of hybrid 324 were statistically different. All sh2 corns had higher pH values. During freezing, soluble solids concentration, sugars and acids decreased whereas pH increased. Frozen cobs exhibited acceptable microbiological rank, with low activities of mesophiles and total coliforms, absence of psychrophiles and fecal coliforms, and an appreciable amount of molds. In conclusion, sh2 hybrids adapted with no problems to the freezing process, they had lower contents of soluble solids and higher contents of total sugars, which almost doubled the amount of su corn; flavor, texture, sweetness and appearance of kernels were also better. Hybrid Victor was preferred by the evaluating panel and had an outstanding performance due to its yield and sensorial characteristics.

Measured solubilities and speciations from oversaturation experiments of neptunium, plutonium, and americium in UE-25p No. 1 well water from the Yucca Mountain region: Milestone report 3329-WBS1.2.3.4.1.3.1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nitsche, H.; Roberts, K.; Prussin, T.

1994-04-01

Solubility and speciation are important in understanding aqueous radionuclide transport through the geosphere. They define the source term for transport retardation processes such as sorption and colloid formation. Solubility and speciation data are useful in verifying the validity of geochemical codes that are a part of predictive transport models. Results are presented from solubility and speciation experiments of {sup 237}NpO{sub 2}{sup +}, {sup 239}Pu{sup 4+}, and {sup 241}Am{sup 3+}/Nd{sup 3+} in a modified UE-25p No. 1 groundwater (from the Yucca Mountain region, Nevada, which is being investigated as a potential high-level nuclear waste disposal site) at two different temperatures (25{degree}more » and 60{degree}C) and three pH values (6.0, 7.0, 8.5). The solubility-controlling steady-state solids were identified and the speciation and/or oxidation states present in the supernatant solutions were determined. The neptunium solubility decreased with increasing temperature and pH. Plutonium concentrations significantly decreased with increasing temperature at pH 6 and 7. The concentration at pH 8.5 hardly decreased at all with increasing temperature. At both temperatures the concentrations were highest at pH 8.5, lowest at pH 7, and in between at pH 6. For the americium/neodymium solutions, the solubility decreased significantly with increasing temperature and increased somewhat with increasing pH.« less

Gypsum addition to soils contaminated by red mud: implications for aluminium, arsenic, molybdenum and vanadium solubility.

PubMed

Lehoux, Alizée P; Lockwood, Cindy L; Mayes, William M; Stewart, Douglas I; Mortimer, Robert J G; Gruiz, Katalin; Burke, Ian T

2013-10-01

Red mud is highly alkaline (pH 13), saline and can contain elevated concentrations of several potentially toxic elements (e.g. Al, As, Mo and V). Release of up to 1 million m(3) of bauxite residue (red mud) suspension from the Ajka repository, western Hungary, caused large-scale contamination of downstream rivers and floodplains. There is now concern about the potential leaching of toxic metal(loid)s from the red mud as some have enhanced solubility at high pH. This study investigated the impact of red mud addition to three different Hungarian soils with respect to trace element solubility and soil geochemistry. The effectiveness of gypsum amendment for the rehabilitation of red mud-contaminated soils was also examined. Red mud addition to soils caused a pH increase, proportional to red mud addition, of up to 4 pH units (e.g. pH 7 → 11). Increasing red mud addition also led to significant increases in salinity, dissolved organic carbon and aqueous trace element concentrations. However, the response was highly soil specific and one of the soils tested buffered pH to around pH 8.5 even with the highest red mud loading tested (33 % w/w); experiments using this soil also had much lower aqueous Al, As and V concentrations. Gypsum addition to soil/red mud mixtures, even at relatively low concentrations (1 % w/w), was sufficient to buffer experimental pH to 7.5-8.5. This effect was attributed to the reaction of Ca(2+) supplied by the gypsum with OH(-) and carbonate from the red mud to precipitate calcite. The lowered pH enhanced trace element sorption and largely inhibited the release of Al, As and V. Mo concentrations, however, were largely unaffected by gypsum induced pH buffering due to the greater solubility of Mo (as molybdate) at circumneutral pH. Gypsum addition also leads to significantly higher porewater salinities, and column experiments demonstrated that this increase in total dissolved solids persisted even after 25 pore volume replacements. Gypsum addition could therefore provide a cheaper alternative to recovery (dig and dump) for the treatment of red mud-affected soils. The observed inhibition of trace metal release within red mud-affected soils was relatively insensitive to either the percentage of red mud or gypsum present, making the treatment easy to apply. However, there is risk that over-application of gypsum could lead to detrimental long-term increases in soil salinity.

Radionuclide solubility and speciation studies for the Yucca Mountain site characterization project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nitsche, H.; Roberts, K.; Prussin, T.

1992-12-01

Yucca Mountain, Nevada, USA, is being investigated for its suitability as a potential site for a geologic nuclear waste repository. As part of the site characterization studies, actinide solubilities and speciations were studied at pH 6, 7, and 8.5 at 25{degrees}C in two different groundwaters from the vicinity of Yucca Mountain. The groundwaters differ substantially in total dissolved carbonate concentration, and to a lesser extent in ionic strength. In the waters with higher carbonate content, the solubilities of neptunium(V) decreased, whereas those americium(III) increased at 25{degrees}KC and decreased at 60{degrees}C. The solids formed were sodium neptunium carbonates and americium hydroxycarbonates.more » Plutonium solubilities did not significantly change with changing water composition because the solubility-controlling solids were mostly amorphous Pu(IV) polymers that contained only small amounts of carbonate.« less

Radionuclide solubility and speciation studies for the Yucca Mountain site characterization project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nitsche, H.; Roberts, K.; Prussin, T.

1993-12-31

Yucca Mountain, Nevada, U.S.A., is being investigated for its suitability as a potential site for a geologic nuclear waste repository. As part of the site characterization studies, actinide solubilities and speciations were studied at pH 6, 7, and 8.5 at 25{degrees} and 60{degrees}C in two different groundwaters from the vicinity of Yucca Mountain. The groundwaters differ substantially in total dissolved carbonate concentration, and to a lesser extent in ionic strength. In the waters with higher carbonate content, the solubilities of neptunium(V) decreased, whereas those of americium (III) increased at 25{degrees}C and decreased at 60{degrees}C. The solids formed were sodium neptuniummore » carbonates and americium hydroxycarbonates. Plutonium solubilities did not significantly change with changing water composition because the solubility-controlling solids were mostly amorphous Pu(IV) polymers that contained only small amounts of carbonate.« less

Marble wastes and pig slurry improve the environmental and plant-relevant properties of mine tailings.

PubMed

Kabas, S; Faz, A; Acosta, J A; Arocena, J M; Zornoza, R; Martínez-Martínez, S; Carmona, D M

2014-02-01

Poor soil fertility is often the biggest challenge to the establishment of vegetation in mine wastes deposits. We conducted field trials in the El Gorguel and El Lirio sites in SE Spain, two representative tailing ponds of similar properties except for pH, to understand the environmental and plant-relevant benefits of marble waste (MW) and pig slurry (PS) applications to mine tailings. Low pH (5.4) tailings (El Lirio) exhibit reduction of up to fourfold in bio-availability of metals as shown by the DTPA-Zn, Pb, water-soluble Zn, Pb and up to 3× for water-soluble Cd. Tailings in El Gorguel have high pH (7.4) and did not exhibit significant trends in the reductions of water-extractable Zn, Pb, Cd and Cu. Improvements to the edaphic (plant-relevant) properties of tailings after the amendments are not as sensitive to pH compared to the environmental characteristics. The two sites had increases in aggregate stability, organic matter (total N and organic C) although total N is higher in the El Gorguel (up to 212 μg N kg(-1)) than the El Lirio (up to 26 μg N kg(-1)). However, cation exchange capacities are similar in both sites at 15.2 cmol(+) kg(-1). We conclude that the characteristics, especially pH, of tailing materials significantly influence the fate of metals but not improvements to plant-relevant properties such as cation exchange capacity and aggregate stability 1 year after the application of MW and PS amendments.

pH-dependent solubility of indomethacin-saccharin and carbamazepine-saccharin cocrystals in aqueous media.

PubMed

Alhalaweh, Amjad; Roy, Lilly; Rodríguez-Hornedo, Naír; Velaga, Sitaram P

2012-09-04

Cocrystals constitute an important class of pharmaceutical solids for their remarkable ability to modulate solubility and pH dependence of water insoluble drugs. Here we show how cocrystals of indomethacin-saccharin (IND-SAC) and carbamazepine-saccharin (CBZ-SAC) enhance solubility and impart a pH-sensitivity different from that of the drugs. IND-SAC exhibited solubilities 13 to 65 times higher than IND at pH values of 1 to 3, whereas CBZ-SAC exhibited a 2 to 10 times higher solubility than CBZ dihydrate. Cocrystal solubility dependence on pH predicted from mathematical models using cocrystal K(sp), and cocrystal component K(a) values, was in excellent agreement with experimental measurements. The cocrystal solubility increase relative to drug was predicted to reach a limiting value for a cocrystal with two acidic components. This limiting value is determined by the ionization constants of cocrystal components. Eutectic constants are shown to be meaningful indicators of cocrystal solubility and its pH dependence. The two contributions to solubility, cocrystal lattice and solvation, were evaluated by thermal and solubility determinations. The results show that solvation is the main barrier for the aqueous solubility of these drugs and their cocrystals, which are orders of magnitude higher than their lattice barriers. Cocrystal increase in solubility is thus a result of decreasing the solvation barrier compared to that of the drug. This work demonstrates the favorable properties of cocrystals and strategies that facilitate their meaningful characterization.

Influence of Boiling Duration of GCSB-5 on Index Compound Content and Antioxidative and Anti-inflammatory Activity.

PubMed

Lee, In-Hee; Chung, Hwa-Jin; Shin, Joon-Shik; Ha, In-Hyuk; Kim, Me-Riong; Koh, Wonil; Lee, Jinho

2017-01-01

GCSB-5, an herbal drug composition with an anti-inflammatory effect, is prepared by boiling, which is the most common herbal extraction method in traditional Korean medicine. Several parameters are involved in the process, i.e., extractant type, herb-to-extractant ratio, extraction temperature and pressure, and total boiling time. The aim of this study was to examine the influence of boiling time on index compound amount and the antioxidative and anti-inflammatory activities of GCSB-5. Different samples of GCSB-5 were obtained by decocting for 30, 60, 90, 120, 150, and 240 min. Each sample was tested for hydrogen ion concentration (pH), total soluble solid content (TSSC), marker compound profiles, and antioxidative and anti-inflammatory activity. pH was found to decrease while TSSC increased with extended decoction. Marker compound contents for GCSB-5 (acanthoside D for Acanthopanax sessiliflorus Seem, 20-hydroxyecdysone for Achyranthes japonica Nakai, and pinoresinol diglucoside for Eucommia ulmoides Oliver) remained relatively constant regardless of the length of boiling. Total D-glucose amount increased with longer boiling. The antioxidative and anti-inflammatory potentials of GCSB-5 were not substantially affected by decoction duration. Biological characteristics and marker compound content of GCSB-5 were not altered significantly in prolonged boiling. Longer boiling duration of GCSB-5 did not increase yield in a time-dependent manner, but yields of 210 and 240 min samples were significantly higherHydrogen ion concentration of GCSB-5 samples decreased while total soluble solid content and D-glucose concentration levels increased with boiling durationAlthough concentrations of some index compounds increased with extended boiling duration of GCSB-5, increase was small and not in a direct proportional relationshipAntioxidative and anti-inflammatory properties of GCSB-5 were not substantially affected by decoction duration. Abbreviations used: CAM: Complementary and alternative medicine; KIOM: Korea Institute of Oriental Medicine; KMD: Korean medicine doctor; TSSC: Total soluble solid content; pH: Hydrogen ion concentration; HPLC: High-performance liquid chromatography; NO: Nitric oxide; NO 2 : Nitric dioxide; LPS: Lipopolysaccharide; DMSO: Dimethyl sulfoxide.

Effect of pH on dissociation of casein micelles in yak skim milk.

PubMed

Yang, M; Zhang, G D; Yang, J T; Sun, D; Wen, P C; Zhang, W B

2018-04-01

The dissociation of yak casein (CN) micelles was evaluated by scanning electron microscopy, particle size, fluorescence properties, and soluble mineral and CN molecule content at pH 4.6 to 8.2. The results showed that the size of CN micelles remained constant with decreasing pH from 8.2 to 5.8 but sharply increased at pH ≤5.4. Casein micelles began to aggregate at pH 5.4, and the serum magnesium, potassium, iron, zinc, copper, and manganese levels had their minimum values at this pH level. During acidification, colloidal calcium phosphate dramatically disassociated from yak CN micelles, but the soluble CN monomer content decreased slightly. During alkalization, the soluble calcium and phosphorus content decreased below pH 6.8 but increased with pH increases from 6.8 to 8.2. However, the soluble CN content increased markedly during alkalization. The emission wavelength of 8-anilino-1-naphthalenesulfonic acid sodium salt fluorescence decreased during both acidification and alkalization from pH 6.6, whereas the opposite was found for intrinsic fluorescence. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Measurement of Soluble and Total Hexavalent Chromium in the Ambient Airborne Particles in New Jersey

PubMed Central

Huang, Lihui; Yu, Chang Ho; Hopke, Philip K.; Lioy, Paul J.; Buckley, Brian T.; Shin, Jin Young; Fan, Zhihua (Tina)

2015-01-01

Hexavalent chromium (Cr(VI)) in ambient airborne particulate matter (PM) is a known pulmonary carcinogen and may have both soluble and insoluble forms. The sum of the two forms is defined as total Cr(VI). Currently, there were no methods suitable for large-scale monitoring of total Cr(VI) in ambient PM. This study developed a method to measure total Cr(VI) in ambient PM. This method includes PM collection using a Teflon filter, microwave extraction with 3% Na2CO3-2% NaOH at 95°C for 60 minutes, and Cr(VI) analysis by 1,5-diphenylcarbazide colorimetry at 540 nm. The recoveries of total Cr(VI) were 119.5 ± 10.4% and 106.3 ± 16.7% for the Cr(VI)-certified reference materials, SQC 012 and SRM 2700, respectively. Total Cr(VI) in the reference urban PM (NIST 1648a) was 26.0 ± 3.1 mg/kg (%CV = 11.9%) determined by this method. The method detection limit was 0.33 ng/m3. This method and the one previously developed to measure ambient Cr(VI), which is soluble in pH ~9.0 aqueous solution, were applied to measure Cr(VI) in ambient PM10 collected from three urban areas and one suburban area in New Jersey. The total Cr(VI) concentrations were 1.05–1.41 ng/m3 in the winter and 0.99–1.56 ng/m3 in the summer. The soluble Cr(VI) concentrations were 0.03–0.19 ng/m3 in the winter and 0.12–0.37 ng/m3 in the summer. The summer mean ratios of soluble to total Cr(VI) were 14.3–43.7%, significantly higher than 4.2–14.4% in the winter. The winter concentrations of soluble and total Cr(VI) in the suburban area were significantly lower than in the three urban areas. The results suggested that formation of Cr(VI) via atmospheric chemistry may contribute to the higher soluble Cr(VI) concentrations in the summer. PMID:26120324

Transport and solubility of Hetero-disperse dry deposition particulate matter subject to urban source area rainfall-runoff processes

NASA Astrophysics Data System (ADS)

Ying, G.; Sansalone, J.

2010-03-01

SummaryWith respect to hydrologic processes, the impervious pavement interface significantly alters relationships between rainfall and runoff. Commensurate with alteration of hydrologic processes the pavement also facilitates transport and solubility of dry deposition particulate matter (PM) in runoff. This study examines dry depositional flux rates, granulometric modification by runoff transport, as well as generation of total dissolved solids (TDS), alkalinity and conductivity in source area runoff resulting from PM solubility. PM is collected from a paved source area transportation corridor (I-10) in Baton Rouge, Louisiana encompassing 17 dry deposition and 8 runoff events. The mass-based granulometric particle size distribution (PSD) is measured and modeled through a cumulative gamma function, while PM surface area distributions across the PSD follow a log-normal distribution. Dry deposition flux rates are modeled as separate first-order exponential functions of previous dry hours (PDH) for PM and suspended, settleable and sediment fractions. When trans-located from dry deposition into runoff, PSDs are modified, with a d50m decreasing from 331 to 14 μm after transport and 60 min of settling. Solubility experiments as a function of pH, contact time and particle size using source area rainfall generate constitutive models to reproduce pH, alkalinity, TDS and alkalinity for historical events. Equilibrium pH, alkalinity and TDS are strongly influenced by particle size and contact times. The constitutive leaching models are combined with measured PSDs from a series of rainfall-runoff events to demonstrate that the model results replicate alkalinity and TDS in runoff from the subject watershed. Results illustrate the granulometry of dry deposition PM, modification of PSDs along the drainage pathway, and the role of PM solubility for generation of TDS, alkalinity and conductivity in urban source area rainfall-runoff.

Solubility and chemistry of materials encountered by beryllium mine and ore extraction workers: relation to risk.

PubMed

Deubner, David C; Sabey, Philip; Huang, Wenjie; Fernandez, Diego; Rudd, Abigail; Johnson, William P; Storrs, Jason; Larson, Rod

2011-10-01

Beryllium mine and ore extraction mill workers have low rates of beryllium sensitization and chronic beryllium disease relative to the level of beryllium exposure. The objective was to relate these rates to the solubility and composition of the mine and mill materials. Medical surveillance and exposure data were summarized. Dissolution of BeO, ore materials and beryllium hydroxide, Be(OH)(2) was measured in synthetic lung fluid. The ore materials were more soluble than BeO at pH 7.2 and similar at pH 4.5. Be(OH)(2) was more soluble than BeO at both pH. Aluminum dissolved along with beryllium from ore materials. Higher solubility of beryllium ore materials and Be(OH)(2) at pH 7.2 might shorten particle longevity in the lung. The aluminum content of the ore materials might inhibit the cellular immune response to beryllium.

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. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

pH-Dependent Liquid-Liquid Phase Separation of Highly Supersaturated Solutions of Weakly Basic Drugs.

PubMed

Indulkar, Anura S; Box, Karl J; Taylor, Robert; Ruiz, Rebeca; Taylor, Lynne S

2015-07-06

Supersaturated solutions of poorly aqueous soluble drugs can be formed both in vivo and in vitro. For example, increases in pH during gastrointestinal transit can decrease the aqueous solubility of weakly basic drugs resulting in supersaturation, in particular when exiting the acidic stomach environment. Recently, it has been observed that highly supersaturated solutions of drugs with low aqueous solubility can undergo liquid-liquid phase separation (LLPS) prior to crystallization, forming a turbid solution such that the concentration of the drug in the continuous solution phase corresponds to the amorphous solubility while the colloidal phase is composed of a disordered drug-rich phase. Although it is well established that the equilibrium solubility of crystalline weakly basic drugs follows the Henderson-Hasselbalch relationship, the impact of pH on the LLPS phenomenon or the amorphous solubility has not been explored. In this work, the LLPS concentration of three weakly basic compounds-clotrimazole, nicardipine, and atazanavir-was determined as a function of pH using three different methods and was compared to the predicted amorphous solubility, which was calculated from the pH-dependent crystalline solubility and by estimating the free energy difference between the amorphous and crystalline forms. It was observed that, similar to crystalline solubility, the experimental amorphous solubility at any pH follows the Henderson-Hasselbalch relation and can be predicted if the amorphous solubility of the free base is known. Excellent agreement between the LLPS concentration and the predicted amorphous solubility was observed. Dissolution studies of amorphous drugs showed that the solution concentration can reach the corresponding LLPS concentration at that pH. Solid-state analysis of the precipitated material confirmed the amorphous nature. This work provides insight into the pH-dependent precipitation behavior of poorly water-soluble compounds and provides a fundamental basis with which to understand the performance of supersaturating dosage forms.

Effect of heavy metals on pH buffering capacity and solubility of Ca, Mg, K, and P in non-spiked and heavy metal-spiked soils.

PubMed

Najafi, Sarvenaz; Jalali, Mohsen

2016-06-01

In many parts of the world, soil acidification and heavy metal contamination has become a serious concern due to the adverse effects on chemical properties of soil and crop yield. The aim of this study was to investigate the effect of pH (in the range of 1 to 3 units above and below the native pH of soils) on calcium (Ca), magnesium (Mg), potassium (K), and phosphorus (P) solubility in non-spiked and heavy metal-spiked soil samples. Spiked samples were prepared by cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) as chloride salts and incubating soils for 40 days. The pH buffering capacity (pHBC) of each sample was determined by plotting the amount of H(+) or OH(-) added (mmol kg(-1)) versus the related pH value. The pHBC of soils ranged from 47.1 to 1302.5 mmol kg(-1) for non-spiked samples and from 45.0 to 1187.4 mmol kg(-1) for spiked soil samples. The pHBC values were higher in soil 2 (non-spiked and spiked) which had higher calcium carbonate content. The results indicated the presence of heavy metals in soils generally decreased the solution pH and pHBC values in spiked samples. In general, solubility of Ca, Mg, and K decreased with increasing equilibrium pH of non-spiked and spiked soil samples. In the case of P, increasing the pH to about 7, decreased the solubility in all soils but further increase of pH from 7, enhanced P solubility. The solubility trends and values for Ca, Mg, and K did not differed significantly in non-spiked and spiked samples. But in the case of P, a reduction in solubility was observed in heavy metal-spiked soils. The information obtained in this study can be useful to make better estimation of the effects of soil pollutants on anion and cation solubility from agricultural and environmental viewpoints.

Core-shell nanofibers of curcumin/cyclodextrin inclusion complex and polylactic acid: Enhanced water solubility and slow release of curcumin.

PubMed

Aytac, Zeynep; Uyar, Tamer

2017-02-25

Core-shell nanofibers were designed via electrospinning using inclusion complex (IC) of model hydrophobic drug (curcumin, CUR) with cyclodextrin (CD) in the core and polymer (polylactic acid, PLA) in the shell (cCUR/HPβCD-IC-sPLA-NF). CD-IC of CUR and HPβCD was formed at 1:2 molar ratio. The successful formation of core-shell nanofibers was revealed by TEM and CLSM images. cCUR/HPβCD-IC-sPLA-NF released CUR slowly but much more in total than PLA-CUR-NF at pH 1 and pH 7.4 due to the restriction of CUR in the core of nanofibers and solubility improvement shown in phase solubility diagram, respectively. Improved antioxidant activity of cCUR/HPβCD-IC-sPLA-NF in methanol:water (1:1) is related with the solubility enhancement achieved in water based system. The slow reaction of cCUR/HPβCD-IC-sPLA-NF in methanol is associated with the shell inhibiting the quick release of CUR. On the other hand, cCUR/HPβCD-IC-sPLA-NF exhibited slightly higher rate of antioxidant activity than PLA-CUR-NF in methanol:water (1:1) owing to the enhanced solubility. To conclude, slow release of CUR was achieved by core-shell nanofiber structure and inclusion complexation of CUR with HPβCD provides high solubility. Briefly, electrospinning of core-shell nanofibers with CD-IC core could offer slow release of drugs as well as solubility enhancement for hydrophobic drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Indomethacin-Kollidon VA64 Extrudates: A Mechanistic Study of pH-Dependent Controlled Release.

PubMed

Tres, Francesco; Treacher, Kevin; Booth, Jonathan; Hughes, Leslie P; Wren, Stephen A C; Aylott, Jonathan W; Burley, Jonathan C

2016-03-07

Because of its weakly acidic nature (pKa of 4.5), indomethacin presents an aqueous solubility that significantly increases when changing from acidic to neutral/alkaline pH (1.5 μg/mL at pH 1.2 and 105.2 μg/mL at pH 7.4). We have therefore investigated the impact of the dissolution medium pH on the dissolution performance of indomethacin:Kollidon VA64 extrudates. The impact of the drug loading on the dissolution properties of these systems was also examined (5%, 15%, 30%, 50%, 70%, and 90% drug loading). Time-resolved Raman spectroscopy along with in-line UV-vis spectrophotometry was employed to directly relate changes in dissolution behavior to physicochemical changes that occur to the extrudate during the test. The dissolution tests were performed in pH 2 HCl (to mimic the stomach conditions), and this was then switched during the experiment to pH 6.8 phosphate buffer (to simulate the poststomach conditions). The rotating disc dissolution rate test was also used to simultaneously measure the dissolution rate of both the drug and the polymer. We found that in pH 2 HCl buffer, for the 15% or higher drug-loaded extrudates, Kollidon VA64 preferentially dissolves from the exterior of the compact leaving an amorphous drug-rich hydrophobic shell, which, similarly to an enteric coating, inhibits the drug release. The in situ formation of an enteric coating has been previously hypothesized, and this has been the first time that is directly observed in a pH-variable dissolution test. The dissolution medium switch to pH 6.8 phosphate buffer, due to the large increase of the aqueous solubility of indomethacin at this pH, leads to rapid dissolution of the material forming the coating and therefore total drug release. In contrast, the 5% extrudate is fully hydrated and quickly dissolves at low pH pointing to a dissolution performance dependent on highly water-soluble Kollidon VA64.

Proteomic comparison of two fractions derived from the transsynaptic scaffold.

PubMed

Phillips, Greg R; Florens, Laurence; Tanaka, Hidekazu; Khaing, Zin Z; Fidler, Lazar; Yates, John R; Colman, David R

2005-09-15

A fraction derived from presynaptic specializations (presynaptic particle fraction; PPF) can be separated from postsynaptic densities (PSD) by adjusting the pH of Triton X-100 (TX-100) extraction of isolated transsynaptic scaffolds. Solubilization of the PPF corresponds to disruption of the presynaptic specialization. We show that the PPF is insoluble to repeated TX-100 extraction at pH 6.0 but becomes soluble in detergent at pH 8.0. By immunolocalization, we find that the major proteins of the PPF, clathrin and dynamin, are concentrated in the presynaptic compartment. By using multidimensional protein identification technology, we compared the protein compositions of the PPF and the PSD fraction. We identified a total of 341 proteins, 50 of which were uniquely found in the PPF, 231 in the PSD fraction, and 60 in both fractions. Comparison of the two fractions revealed a relatively low proportion of actin and associated proteins and a high proportion of vesicle or intracellular compartment proteins in the PPF. We conclude that the PPF consists of presynaptic proteins not connected to the actin-based synaptic framework; its insolubility in pH 6 and solubility in pH 8 buffered detergent suggests that clathrin might be an anchorage scaffold for many proteins in the PPF. (c) 2005 Wiley-Liss, Inc.

In vitro dynamic solubility test: influence of various parameters.

PubMed Central

Thélohan, S; de Meringo, A

1994-01-01

This article discusses the dissolution of mineral fibers in simulated physiological fluids (SPF), and the parameters that affect the solubility measurement in a dynamic test where an SPF runs through a cell containing fibers (Scholze and Conradt test). Solutions simulate either the extracellular fluid (pH 7.6) or the intracellular fluid (pH 4.5). The fibers have various chemical compositions and are either continuously drawn or processed as wool. The fiber solubility is determined by the amount of SiO2 (and occasionally other ions) released in the solution. Results are stated as percentage of the initial silica content released or as dissolution rate v in nm/day. The reproducibility of the test is higher with the less soluble fibers (10% solubility), than with highly soluble fibers (20% solubility). The influence of test parameters, including SPF, test duration, and surface area/volume (SA/V), has been studied. The pH and the inorganic buffer salts have a major influence: industrial glasswool composition is soluble at pH 7.6 but not at pH 4.5. The opposite is true for rock- (basalt) wool composition. For slightly soluble fibers, the dissolution rate v remains constant with time, whereas for highly soluble fibers, the dissolution rate decreases rapidly. The dissolution rates believed to occur are v1, initial dissolution rate, and v2, dissolution rate of the residual fibers. The SA of fibers varies with the mass of the fibers tested, or with the fiber diameter at equal mass. Volume, V, is the chosen flow rate. An increase in the SA/V ratio leads to a decrease in the dissolution rate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7882964

In vitro dynamic solubility test: influence of various parameters.

PubMed

Thélohan, S; de Meringo, A

1994-10-01

This article discusses the dissolution of mineral fibers in simulated physiological fluids (SPF), and the parameters that affect the solubility measurement in a dynamic test where an SPF runs through a cell containing fibers (Scholze and Conradt test). Solutions simulate either the extracellular fluid (pH 7.6) or the intracellular fluid (pH 4.5). The fibers have various chemical compositions and are either continuously drawn or processed as wool. The fiber solubility is determined by the amount of SiO2 (and occasionally other ions) released in the solution. Results are stated as percentage of the initial silica content released or as dissolution rate v in nm/day. The reproducibility of the test is higher with the less soluble fibers (10% solubility), than with highly soluble fibers (20% solubility). The influence of test parameters, including SPF, test duration, and surface area/volume (SA/V), has been studied. The pH and the inorganic buffer salts have a major influence: industrial glasswool composition is soluble at pH 7.6 but not at pH 4.5. The opposite is true for rock- (basalt) wool composition. For slightly soluble fibers, the dissolution rate v remains constant with time, whereas for highly soluble fibers, the dissolution rate decreases rapidly. The dissolution rates believed to occur are v1, initial dissolution rate, and v2, dissolution rate of the residual fibers. The SA of fibers varies with the mass of the fibers tested, or with the fiber diameter at equal mass. Volume, V, is the chosen flow rate. An increase in the SA/V ratio leads to a decrease in the dissolution rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of temperature and pH on the solubility of caseins: environmental influences on the dissociation of α(S)- and β-casein.

PubMed

Post, A E; Arnold, B; Weiss, J; Hinrichs, J

2012-04-01

Selective precipitation is a common method for the isolation of β-casein, using the different calcium sensitivities of the individual caseins and the selective solubility of β-casein at a low temperature. In previous studies, it has been indicated that the β-casein yield depends on the physicochemical characteristics of the casein raw material used for fractionation. The objective of this study was to evaluate and compare the solubility of α(S)- and β-casein in solutions of micellar casein, sodium caseinate, and calcium caseinate as a function of pH and temperature. Additionally, the solubility of isolated α(S)- and β-casein fractions in demineralized water, ultrafiltration permeate, and a calcium-depleted milk salt solution was investigated depending on the pH and temperature. Furthermore, micellar casein, sodium caseinate, and calcium caseinate were subjected to a calcium chloride-precipitation process to determine the solubility of α(S)- and β-casein in calcium chloride precipitate, which is produced during selective precipitation, as a function of temperature and pH. Generally, the temperature had only a marginal influence on the α(S)-casein solubility compared with the β-casein solubility, whereas the solubility was shown to be strongly influenced by the pH. Our results suggest that the yield of β-casein obtained during isolation by means of selective precipitation may be a result of the solubility characteristics of α(S)- and β-casein in calcium chloride precipitate. Manufacturers may consider a simple solubility experiment before the β-casein isolation process by means of selective precipitation to predict β-casein yield. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Osmotic pellet system comprising osmotic core and in-process amorphized drug in polymer-surfactant layer for controlled delivery of poorly water-soluble drug.

PubMed

Saindane, Nilesh; Vavia, Pradeep

2012-09-01

The aim of the present investigation was to develop controlled porosity osmotic system for poorly water-soluble drug based on drug in polymer-surfactant layer technology. A poorly water-soluble drug, glipizide (GZ), was selected as the model drug. The technology involved core of the pellets containing osmotic agent coated with drug dispersed in polymer and surfactant layer, finally coated with release-retardant layer with pore former. The optimized drug-layer-coated pellets were evaluated for solubility of GZ at different pH conditions and characterized for amorphous nature of the drug by differential scanning calorimetry and X-ray powder diffractometry. The optimized release-retardant layer pellets were evaluated for in vitro drug release at different pH, hydrodynamic, and osmolality conditions. The optimized drug layer showed improvement in solubility (10 times in pH 1.2, 11 times in pH 4.5, and 21 times in pH 6.8), whereas pellets coated with cellulose acetate (15.0%, w/w, weight gain) with pore former triethyl citrate (10.0%, w/w, of polymer) demonstrated zero-order drug release for 24 h at different pH conditions; moreover, retardation of drug release was observed with increment of osmolality. This system could be a platform technology for controlled delivery of poorly water-soluble drugs. Copyright © 2012 Wiley Periodicals, Inc.

Understanding the Differences Between Cocrystal and Salt Aqueous Solubilities.

PubMed

Cavanagh, Katie L; Maheshwari, Chinmay; Rodríguez-Hornedo, Naír

2018-01-01

This work challenges the popular notion that pharmaceutical salts are more soluble than cocrystals. There are cocrystals that are more soluble than salt forms of a drug and vice-versa. It all depends on the interplay between the chemistry of both the solid and solution phases. Aqueous solubility, pH max , and supersaturation index (SA = S CC /S D or S salt /S D ) of cocrystals and salts of a basic drug, lamotrigine (LTG), were determined, and mathematical models that predict the influence of cocrystal/salt K sp and K a were derived. K sp and SA followed the order LTG-nicotinamide cocrystal (18) > LTG-HCl salt (12) > LTG-saccharin salt (5) > LTG-methylparaben cocrystal (1) > LTG-phenobarbital cocrystal (0.2). The values in parenthesis represent SA under nonionizing conditions. Cocrystal/salt solubility and thermodynamic stability are determined by pH and will drastically change with a single unit change in pH. pH max values ranged from 5.0 (saccharin salt) to 6.4 (methylparaben cocrystal) to 9.0 (phenobarbital cocrystal). Cocrystal/salt pH max dependence on pK sp and pK a shows that cocrystals and salts exhibit different behavior. Solubility and pH max are as important as supersaturation index in assessing the stability and risks associated with conversions of supersaturating forms. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

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

PubMed

Albino, John D; Nambi, Indumathi M

2009-12-01

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

Solubility of water in lunar basalt at low pH2O

NASA Astrophysics Data System (ADS)

Newcombe, M. E.; Brett, A.; Beckett, J. R.; Baker, M. B.; Newman, S.; Guan, Y.; Eiler, J. M.; Stolper, E. M.

2017-03-01

We report the solubility of water in Apollo 15 basaltic "Yellow Glass" and an iron-free basaltic analog composition at 1 atm and 1350 °C. We equilibrated melts in a 1-atm furnace with flowing H2/CO2 gas mixtures that spanned ∼8 orders of magnitude in fO2 (from three orders of magnitude more reducing than the iron-wüstite buffer, IW-3.0, to IW+4.8) and ∼4 orders of magnitude in pH2/pH2O (from 0.003 to 24). Based on Fourier transform infrared spectroscopy (FTIR), our quenched experimental glasses contain 69-425 ppm total water (by weight). Our results demonstrate that under the conditions of our experiments: (1) hydroxyl is the only H-bearing species detected by FTIR; (2) the solubility of water is proportional to the square root of pH2O in the furnace atmosphere and is independent of fO2 and pH2/pH2O; (3) the solubility of water is very similar in both melt compositions; (4) the concentration of H2 in our iron-free experiments is <∼4 ppm, even at oxygen fugacities as low as IW-2.3 and pH2/pH2O as high as 11; (5) Secondary ion mass spectrometry (SIMS) analyses of water in iron-rich glasses equilibrated under variable fO2 conditions may be strongly influenced by matrix effects, even when the concentration of water in the glasses is low; and (6) Our results can be used to constrain the entrapment pressure of lunar melt inclusions and the partial pressures of water and molecular hydrogen in the carrier gas of the lunar pyroclastic glass beads. We find that the most water-rich melt inclusion of Hauri et al. (2011) would be in equilibrium with a vapor with pH2O ∼ 3 bar and pH2 ∼ 8 bar. We constrain the partial pressures of water and molecular hydrogen in the carrier gas of the lunar pyroclastic glass beads to be 0.0005 bar and 0.0011 bar respectively. We calculate that batch degassing of lunar magmas containing initial volatile contents of 1200 ppm H2O (dissolved primarily as hydroxyl) and 4-64 ppm C would produce enough vapor to reach the critical vapor volume fraction thought to be required for magma fragmentation (∼65-75 vol.%) at a total pressure of ∼5 bar (corresponding to a depth beneath the lunar surface of ∼120 m). At a fragmentation pressure of ∼5 bar, the calculated vapor composition is dominated by H2, supporting the hypothesis that H2, rather than CO, was the primary propellant of the lunar fire fountain eruptions. The results of our batch degassing model suggest that initial melt compositions with >∼200 ppm C would be required for the vapor composition to be dominated by CO rather than H2 at 65-75% vesicularity.

Sorption processes affecting arsenic solubility in oxidized surface sediments from Tulare Lake Bed, California

USGS Publications Warehouse

Gao, S.; Goldberg, S.; Herbel, M.J.; Chalmers, A.T.; Fujii, R.; Tanji, K.K.

2006-01-01

Elevated concentrations of arsenic (As) in shallow groundwater in Tulare Basin pose an environmental risk because of the carcinogenic properties of As and the potential for its migration to deep aquifers that could serve as a future drinking water source. Adsorption and desorption are hypothesized to be the major processes controlling As solubility in oxidized surface sediments where arsenate [As(V)] is dominant. This study examined the relationship between sorption processes and arsenic solubility in shallow sediments from the dry Tulare Lake bed by determining sorption isotherms, pH effect on solubility, and desorption-readsorption behavior (hysteresis), and by using a surface complexation model to describe sorption. The sediments showed a high capacity to adsorb As(V). Estimates of the maximum adsorption capacity were 92 mg As kg- 1 at pH 7.5 and 70 mg As kg- 1 at pH 8.5 obtained using the Langmuir adsorption isotherm. Soluble arsenic [> 97% As(V)] did not increase dramatically until above pH 10. In the native pH range (7.5-8.5), soluble As concentrations were close to the lowest, indicating that As was strongly retained on the sediment. A surface complexation model, the constant capacitance model, was able to provide a simultaneous fit to both adsorption isotherms (pH 7.5 and 8.5) and the adsorption envelope (pH effect on soluble As), although the data ranges are one order of magnitude different. A hysteresis phenomenon between As adsorbed on the sediment and As in solution phase was observed in the desorption-readsorption processes and differs from conventional hysteresis observed in adsorption-desorption processes. The cause is most likely due to modification of adsorbent surfaces in sediment samples upon extensive extractions (or desorption). The significance of the hysteresis phenomenon in affecting As solubility and mobility may be better understood by further microscopic studies of As interaction mechanisms with sediments subjected to extensive leaching in natural environments. ?? 2006 Elsevier B.V. All rights reserved.

Atmospheric Processing of Volcanic Glass: Effects on Iron Solubility and Redox Speciation.

PubMed

Maters, Elena C; Delmelle, Pierre; Bonneville, Steeve

2016-05-17

Volcanic ash from explosive eruptions can provide iron (Fe) to oceanic regions where this micronutrient limits primary production. Controls on the soluble Fe fraction in ash remain poorly understood but Fe solubility is likely influenced during atmospheric transport by condensation-evaporation cycles which induce large pH fluctuations. Using glass powder as surrogate for ash, we experimentally simulate its atmospheric processing via cycles of pH 2 and 5 exposure. Glass fractional Fe solubility (maximum 0.4%) is governed by the pH 2 exposure duration rather than by the pH fluctuations, however; pH 5 exposure induces precipitation of Fe-bearing nanoparticles which (re)dissolve at pH 2. Glass leaching/dissolution release Fe(II) and Fe(III) which are differentially affected by changes in pH; the average dissolved Fe(II)/Fetot ratio is ∼0.09 at pH 2 versus ∼0.18 at pH 5. Iron release at pH 2 from glass with a relatively high bulk Fe(II)/Fetot ratio (0.5), limited aqueous Fe(II) oxidation at pH 5, and possibly glass-mediated aqueous Fe(III) reduction may render atmospherically processed ash a significant source of Fe(II) for phytoplankton. By providing new insight into the form(s) of Fe associated with ash as wet aerosol versus cloud droplet, we improve knowledge of atmospheric controls on volcanogenic Fe delivery to the ocean.

Improved sludge dewaterability and hydrolysis performance after pretreatment with Fenton's reagent.

PubMed

Yuan, Hongying; Yang, Yuping; Yuan, Jian; Wang, Yanning; Song, Yameng; Lu, Jingfang; Song, Jianyang

2018-01-01

The dewaterability of excess sludge significantly improved upon pretreatment with Fenton's reagent in this study. After 0.9 g/L of Fe 2+ and 5.0 g/L of H 2 O 2 were added to the sludge, and reacted for 2 h at pH = 4, the specific resistance to filtration (SRF) of the excess sludge decreased from an initial value of 29.74 × 10 12 m/kg to 6.49 × 10 12 m/kg. The factors that affected this improvement in sludge dewaterability as evaluated by SRF reduction showed the following order: H 2 O 2 > pH > Fe 2+ > reaction time. Furthermore, the hydrolysis performance of the sludge under the optimal reaction conditions was investigated. The results indicated that the concentration of soluble chemical oxygen demand in the supernatant increased almost 14 times compared to raw sludge, and the contents of soluble protein and soluble polysaccharide were more than 8 and 17 times higher, respectively, than for the untreated situation. However, the amounts of ammonia nitrogen (NH 4 + -N) and phosphate (PO 4 3- -P) released from the sludge showed different trends: NH 4 + -N increased by 200%, while PO 4 3- -P decreased by 82%. The production of volatile fatty acids (VFAs) from the treated sludge showed that total VFAs increased by 66%, and iso-butylacetic acid was the dominant product among the total VFAs.

Fraction of a dose absorbed estimation for structurally diverse low solubility compounds.

PubMed

Sugano, Kiyohiko

2011-02-28

The purpose of the present study was to investigate the prediction accuracy of the fully mechanistic gastrointestinal unified theoretical (GUT) framework for in vivo oral absorption of low solubility drugs. Solubility in biorelevant media, molecular weight, logP(oct), pK(a), Caco-2 permeability, dose and particle size were used as the input parameters. To neglect the effect of the low stomach pH on dissolution of a drug, the fraction of a dose absorbed (Fa%) of undissociable and free acids were used. In addition, Fa% of free base drugs with the high pH stomach was also included to increase the number of model drugs. In total twenty nine structurally diverse compounds were used as the model drugs. Fa% data at several doses and particle sizes in humans and dogs were collated from the literature (total 110 Fa% data). In approximately 80% cases, the prediction error was within 2 fold, suggesting that the GUT framework has practical predictability for drug discovery, but not for drug development. The GUT framework appropriately captured the dose and particle size dependency of Fa% as the particle drifting effect was taken into account. It should be noted that the present validation results cannot be applied for salt form cases and other special formulations such as solid dispersions and emulsion formulations. Copyright © 2010 Elsevier B.V. All rights reserved.

Strategies to overcome pH-dependent solubility of weakly basic drugs by using different types of alginates.

PubMed

Gutsche, S; Krause, M; Kranz, H

2008-12-01

Weakly basic drugs demonstrate higher solubility at lower pH, thus often leading to faster drug release at lower pH. The objective of this study was to achieve pH-independent release of weakly basic drugs from extended release formulations based on the naturally occurring polymer sodium alginate. Three approaches to overcome the pH-dependent solubility of the weakly basic model drug verapamil hydrochloride were investigated. First, matrix tablets were prepared by direct compression of drug substance with different types of sodium alginate only. Second, pH-modifiers were added to the drug/alginate matrix systems. Third, press-coated tablets consisting of an inner pH-modifier tablet core and an outer drug/sodium alginate coat were prepared. pH-Independent drug release was achieved from matrix tablets consisting of selected alginates and drug substance only. Alginates are better soluble at higher pH. Therefore, they are able to compensate the poor solubility of weakly basic drugs at higher pH as the matrix of the tablets dissolves faster. This approach was successful when using alginates that demonstrated fast hydration and erosion at higher pH. The approach failed for alginates with less-pronounced erosion at higher pH. The addition of fumaric acid to drug/alginate-based matrix systems decreased the microenvironmental pH within the tablets thus increasing the solubility of the weakly basic drug at higher pH. Therefore, pH-independent drug release was achieved irrespective of the type of alginate used. Drug release from press-coated tablets did not provide any further advantages as compound release remained pH-dependent.

Influence of indian mustard (Brassica juncea) on rhizosphere soil solution chemistry in long-term contaminated soils: a rhizobox study.

PubMed

Kim, Kwon-Rae; Owens, Gary; Kwon, Soon-lk

2010-01-01

This study investigated the influence of Indian mustard (Brassica juncea) root exudation on soil solution properties (pH, dissolved organic carbon (DOC), metal solubility) in the rhizosphere using a rhizobox. Measurement was conducted following the cultivation of Indian mustard in the rhizobox filled four different types of heavy metal contaminated soils (two alkaline soils and two acidic soils). The growth of Indian mustard resulted in a significant increase (by 0.6 pH units) in rhizosphere soil solution pH of acidic soils and only a slight increase (< 0.1 pH units) in alkaline soils. Furthermore, the DOC concentration increased by 17-156 mg/L in the rhizosphere regardless of soil type and the extent of contamination, demonstrating the exudation of DOC from root. Ion chromatographic determination showed a marked increase in the total dissolved organic acids (OAs) in rhizosphere. While root exudates were observed in all soils, the amount of DOC and OAs in soil solution varied considerably amongst different soils, resulting in significant changes to soil solution metals in the rhizosphere. For example, the soil solution Cd, Cu, Pb, and Zn concentrations increased in the rhizosphere of alkaline soils compared to bulk soil following plant cultivation. In contrast, the soluble concentrations of Cd, Pb, and Zn in acidic soils decreased in rhizosphere soil when compared to bulk soils. Besides the influence of pH and DOC on metal solubility, the increase of heavy metal concentration having high stability constant such as Cu and Pb resulted in a release of Cd and Zn from solid phase to liquid phase.

[Determination of equilibrium solubility and n-octanol/water partition coefficient of pulchinenosiden D by HPLC].

PubMed

Rao, Xiao-Yong; Yin, Shan; Zhang, Guo-Song; Luo, Xiao-Jian; Jian, Hui; Feng, Yu-Lin; Yang, Shi-Lin

2014-05-01

To determine the equilibrium solubility of pulchinenosiden D in different solvents and its n-octanol/water partition coefficients. Combining shaking flask method and high performance liquid chromatography (HPLC) to detect the n-octanol/water partition coefficients of pulchinenosiden D, the equilibrium solubility of pulchinenosiden D in six organic solvents and different pH buffer solution were determined by HPLC analysis. n-Octanol/water partition coefficients of pulchinenosiden D in different pH were greater than zero, the equilibrium solubility of pulchinenosiden D was increased with increase the pH of the buffer solution. The maximum equilibrium solubility of pulchinenosiden D was 255.89 g x L(-1) in methanol, and minimum equilibrium solubility of pulchinenosiden D was 0.20 g x L(-1) in acetonitrile. Under gastrointestinal physiological conditions, pulchinenosiden D exists in molecular state and it has good absorption but poor water-solubility, so increasing the dissolution rate of pulchinenosiden D may enhance its bioavailability.

Influence of pH, particle size and crystal form on dissolution behaviour of engineered nanomaterials.

PubMed

Avramescu, M-L; Rasmussen, P E; Chénier, M; Gardner, H D

2017-01-01

Solubility is a critical component of physicochemical characterisation of engineered nanomaterials (ENMs) and an important parameter in their risk assessments. Standard testing methodologies are needed to estimate the dissolution behaviour and biodurability (half-life) of ENMs in biological fluids. The effect of pH, particle size and crystal form on dissolution behaviour of zinc metal, ZnO and TiO 2 was investigated using a simple 2 h solubility assay at body temperature (37 °C) and two pH conditions (1.5 and 7) to approximately frame the pH range found in human body fluids. Time series dissolution experiments were then conducted to determine rate constants and half-lives. Dissolution characteristics of investigated ENMs were compared with those of their bulk analogues for both pH conditions. Two crystal forms of TiO 2 were considered: anatase and rutile. For all compounds studied, and at both pH conditions, the short solubility assays and the time series experiments consistently showed that biodurability of the bulk analogues was equal to or greater than biodurability of the corresponding nanomaterials. The results showed that particle size and crystal form of inorganic ENMs were important properties that influenced dissolution behaviour and biodurability. All ENMs and bulk analogues displayed significantly higher solubility at low pH than at neutral pH. In the context of classification and read-across approaches, the pH of the dissolution medium was the key parameter. The main implication is that pH and temperature should be specified in solubility testing when evaluating ENM dissolution in human body fluids, even for preliminary (tier 1) screening.

pH Effects on solubility, zeta potential, and correlation between antibacterial activity and molecular weight of chitosan.

PubMed

Chang, Shun-Hsien; Lin, Hong-Ting Victor; Wu, Guan-James; Tsai, Guo Jane

2015-12-10

Six chitosans with molecular weights (MWs) of 300, 156, 72.1, 29.2, 7.1, and 3.3 kDa were prepared by cellulase degradation of chitosan (300 kDa) and ultrafiltration techniques. We examined the correlation between activity against Escherichia coli and Staphylococcus aureus and chitosan MW, and provided the underlying explanation. In acidic pH conditions, the chitosan activity increased with increasing MW, irrespective of the temperature and bacteria tested. However, at neutral pH, chitosan activity increased as the MW decreased, and little activity was observed for chitosans with MW >29.2 kDa. At pH 5.0 and 6.0, chitosans exhibited good water solubility and zeta potential (ZP) decreased with the MW, whereas the solubility and ZP of the chitosans decreased with increasing MW at pH 7.0. Particularly, low solubility and negative ZP values were determined for chitosans with MW >29.2 kDa, which may explain the loss of their antibacterial activity at pH 7.0. Copyright © 2015 Elsevier Ltd. All rights reserved.

Vertical Migration Potential of Metal Contaminants at Small Arms Firing Ranges, Camp Edwards Military Reservation, Massachusetts.

DTIC Science & Technology

1998-03-01

halloysite on lead concentration in solution 57 Figure 41. Solubility of lead carbonate as a function of pH for a total activity aH2C03...Effects of adsorption by halloysite (a clay) on lead concentration in solution. Contours are equilibrium lead concentrations at different clay

Evaluation of three pumpkin species: correlation with physicochemical, antioxidant properties and classification using SPME-GC-MS and E-nose methods.

PubMed

Zhou, Chun-Li; Mi, Li; Hu, Xue-Yan; Zhu, Bi-Hua

2017-09-01

To ascertain the most discriminant variables for three pumpkin species principal component analysis (PCA) was performed. Twenty-four parameters (pH, conductivity, sucrose, glucose, total soluble solids, L* , a* , b* , individual weight, edible rate, firmness, citric acid, fumaric acid, l-ascorbic acid, malic acid, PPO activity, POD activity, total flavonoids, vitamin E, total phenolics, DPPH, FRAP, β-carotene, and aroma) were considered. The studied pumpkin species were Cucurbita maxima , Cucurbita moschata , and Cucurbita pepo . Three pumpkin species were classified by PCA based on aroma, physicochemical and antioxidant properties because the sum of PC1 and PC2 were both greater than 85% (85.06 and 93.64% respectively). Results were validated by the PCA and showed that PPO activity, total flavonoid, sucrose, glucose, TSS, a* , pH, malic acid, vitamin E, DPPH, FRAP and β-carotene, and aroma are highly useful parameters to classify pumpkin species.

Expression of nattokinase in Escherichia coli and renaturation of its inclusion body.

PubMed

Ni, He; Guo, Peng-Cheng; Jiang, Wei-Ling; Fan, Xiao-Min; Luo, Xiang-Yu; Li, Hai-Hang

2016-08-10

Nattokinase is an important fibrinolytic enzyme with therapeutic applications for cardiovascular diseases. The full-length and mature nattokinase genes were cloned from Bacillus subtilis var. natto and expressed in pQE30 vector in Escherichia coli. The full-length gene expressed low nattokinase activity in the intracellular soluble and the medium fractions. The mature gene expressed low soluble nattokinase activity and large amount insoluble protein in inclusion bodies without enzyme activity. Large amount of refolding solutions (RSs) at different pH values were screening and RS-10 and RS-11 at pH 9 were selected to refold nattokinase inclusion bodies. The recombinant cells were lysed with 0.1mg/mL lysozyme and ultrasonic treatment. After centrifugation, the pellete was washed twice with 20mM Tris-HCl buffer (pH 7.5) containing 1% Triton X-100 to purify the inclusion bodies. The inclusion bodies were dissolved in water at pH 12.0 and refolded with RS-10. The refolded proteins showed 42.8IU/mg and 79.3IU/mg fibrinolytic activity by the traditional dilution method (20-fold dilution into RS-10) and the directly mixing the protein solution with equal volume RS-10, respectively, compared to the 52.0IU/mg of total water-soluble proteins from B. subtilis var. natto. This work demonstrated that the inclusion body of recombinant nattokinase expressed in E. coli could be simply refolded to the natural enzyme activity level by directly mixing the protein solution with equal volume refolding solution. Copyright © 2016 Elsevier B.V. All rights reserved.

The preparation and evaluation of salt forms of linogliride with reduced solubilities as candidates for extended release.

PubMed

Chrzanowski, Frank A; Ahmad, Kaleem

2017-03-01

Salts of linogliride with reduced solubilities were prepared and evaluated as potential candidates for extended-release oral dosage forms. A once-daily dose of 300-800 mg was intended. Seven acids were selected: p-acetamidobenzoic, benzoic, p-hydroxybenzoic, 3-hydroxy-2-naphthoic, 1-napsylic, pamoic, and p-toluenesulfonic acids but only four salts were able to be prepared in suitable quantities for evaluation: linogliride pamoate, p-hydroxybenzoate, 3-hydroxy-2-naphthoate, and 1-napsylate. The pH-solubility profiles of the four new salts, free base, and fumarate salt were compared over the pH 1.43-8.3 range and the intrinsic dissolution rates of the four new salts and the free base were determined at pH 1.43, 4.4, and 7.5. The range of the pH-solubility profile and intrinsic dissolution rates of the p-hydroxybenzoate salt were less than the free base and fumarate and higher than the other three new salts. The pH-solubilities and intrinsic dissolution rates of the 1-napsylate salt were pH-independent. The solubilities and intrinsic dissolution rates of the pamoate and 3-hydroxy-2-naphthoate were higher at pH 1.4-3.4 than at higher pH. At pH 4.4 and higher, the solubilities were essentially the same, in the 1-2 mg/mL range. The intrinsic dissolution rates were also very low and not very different. Dissolution studies with capsules containing 800 mg doses of the pamoate, 1-napsylate, free base, and fumarate performed in a dissolution medium of pH beginning at 2.2 and ending at 6.8 demonstrated that the pamoate and 1-napsylate salt forms dissolved slower and could be useful as extended-release forms.

Effects of rice bran fiber on heat-induced gel prepared with pork salt-soluble meat proteins in model system.

PubMed

Choi, Yun-Sang; Choi, Ji-Hun; Han, Doo-Jeong; Kim, Hack-Youn; Lee, Mi-Ai; Kim, Hyun-Wook; Jeong, Jong-Youn; Kim, Cheon-Jei

2011-05-01

The technological effects of rice bran fiber on pork salt-soluble meat proteins in a model system were investigated. Rice bran fiber at levels of 0% (control), 0.1%, 0.5%, 1%, and 2% was added at the same time as salt-soluble meat protein to maintain similar moisture levels in all samples. Samples with increasing amounts of added rice bran fiber had higher pH, yellowness, sarcoplasmic and total protein solubilities. The moisture content, myofibrillar protein solubility and water holding capacity were the highest in the treatments containing with 1% rice bran fiber. However, the lightness and redness, textural properties decreased with increasing rice bran fiber levels. SDS gel electrophoresis did not reveal any changes in proteins regardless different rice bran fiber levels. The apparent viscosity indicated that improvements in water holding capacity and decreased texture due to added rice bran fiber. Copyright © 2010 The American Meat Science Association. All rights reserved.

Solubility and crystallization of xylose isomerase from Streptomyces rubiginosus

NASA Astrophysics Data System (ADS)

Vuolanto, Antti; Uotila, Sinikka; Leisola, Matti; Visuri, Kalevi

2003-10-01

We have studied the crystallization and crystal solubility of xylose isomerase (XI) from Streptomyces rubiginosus. In this paper, we show a rational approach for developing a large-scale crystallization process for XI. Firstly, we measured the crystal solubility in salt solutions with respect to salt concentration, temperature and pH. In ammonium sulfate the solubility of XI decreased logarithmically when increasing the salt concentration. Surprisingly, the XI crystals had a solubility minimum at low concentration of magnesium sulfate. The solubility of XI in 0.17 M magnesium sulfate was less than 0.5 g l -1. The solubility of XI increased logarithmically when increasing the temperature. We also found a solubility minimum around pH 7. This is far from the isoelectric point of XI (pH 3.95). Secondly, based on the solubility study, we developed a large-scale crystallization process for XI. In a simple and economical cooling crystallization of XI from 0.17 M magnesium sulfate solution, the recovery of crystalline active enzyme was over 95%. Moreover, we developed a process for production of uniform crystals and produced homogenous crystals with average crystal sizes between 12 and 360 μm.

Effect of increasing the colloidal calcium phosphate of milk on the texture and microstructure of yogurt.

PubMed

Ozcan, T; Horne, D; Lucey, J A

2011-11-01

The effect of increasing the colloidal calcium phosphate (CCP) content on the physical, rheological, and microstructural properties of yogurt was investigated. The CCP content of heated (85°C for 30 min) milk was increased by increasing the pH by the addition of alkali (NaOH). Alkalized milk was dialyzed against pasteurized skim milk at approximately 4°C for 72 h to attempt to restore the original pH and soluble Ca content. By adjustment of the milk to pH values 7.45, 8.84, 10.06, and 10.73, the CCP content was increased to approximately 107, 116, 123, and 128%, respectively, relative to the concentration in heated milk. During fermentation of milk, the storage modulus (G') and loss tangent values of yogurts were measured using dynamic oscillatory rheology. Large deformation rheological properties were also measured. The microstructure of yogurt was observed using fluorescence microscopy, and whey separation was determined. Acid-base titration was used to evaluate changes in the CCP content in milk. Total Ca and casein-bound Ca increased with an increase in the pH value of alkalization. During acidification, elevated buffering occurred in milk between pH values 6.7 to 5.2 with an increase in the pH of alkalization. When acidified milk was titrated with alkali, elevated buffering occurred in milk between pH values 5.6 to 6.4 with an increase in the pH of alkalization. The high residual pH of milk after dialysis could be responsible for the decreased contents of soluble Ca in these milks. The pH of gelation was higher in all dialyzed samples compared with the heated control milk, and the gelation pH was higher with an increase in CCP content. The sample with highest CCP content (128%) exhibited gelation at very high pH (6.3), which could be due to alkali-induced CN micellar disruption. The G' values at pH 4.6 were similar in gels with CCP levels up to 116%; at higher CCP levels, the G' values at pH 4.6 greatly decreased. Loss tangent values at pH 5.1 were similar in all samples except in gels with a CCP level of 128%. For dialyzed milk, the whey separation levels were similar in gels made from milk with up to 107% CCP but increased at higher CCP levels. Microstructure of yogurt gels made from milk with 100 to 107% CCP was similar but very large clusters were observed in gels made from milk with higher CCP levels. By dialyzing heated milk against pasteurized milk, we may have retained some heat-induced Ca phosphate on micelles that normally dissolves on cooling because, during dialysis, pasteurized milk provided soluble Ca ions to the heated milk system. Yogurt texture was significantly affected by increasing the casein-bound Ca (and total Ca) content of milk as well as by the alkalization procedure involved in that approach. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

How gastric lipase, an interfacial enzyme with a Ser-His-Asp catalytic triad, acts optimally at acidic pH.

PubMed

Chahinian, Henri; Snabe, Torben; Attias, Coralie; Fojan, Peter; Petersen, Steffen B; Carrière, Frédéric

2006-01-24

Gastric lipase is active under acidic conditions and shows optimum activity on insoluble triglycerides at pH 4. The present results show that gastric lipase also acts in solution on vinyl butyrate, with an optimum activity above pH 7, which suggests that gastric lipase is able to hydrolyze ester bonds via the classical mechanism of serine hydrolases. These results support previous structural studies in which the catalytic triad of gastric lipase was reported to show no specific features. The optimum activity of gastric lipase shifted toward lower pH values, however, when the vinyl butyrate concentration was greater than the solubility limit. Experiments performed with long-chain triglycerides showed that gastric lipase binds optimally to the oil-water interface at low pH values. To study the effects of the pH on the adsorption step independently from substrate hydrolysis, gastric lipase adsorption on solid hydrophobic surfaces was monitored by total internal reflection fluorescence (TIRF), as well as using a quartz crystal microbalance. Both techniques showed a pH-dependent reversible gastric lipase adsorption process, which was optimum at pH 5 (Kd = 6.5 nM). Lipase adsorption and desorption constants (ka = 147,860 M(-1) s(-1) and kd = 139 x 10(-4) s(-1) at pH 6) were estimated from TIRF experiments. These results indicate that the optimum activity of gastric lipase at acidic pH is only "apparent" and results from the fact that lipase adsorption at lipid-water interfaces is the pH-dependent limiting step in the overall process of insoluble substrate hydrolysis. This specific kinetic feature of interfacial enzymology should be taken into account when studying any soluble enzyme acting on an insoluble substrate.

Temperature, soluble solids and pH effect on Alicyclobacillus acidoterrestris viability in lemon juice concentrate.

PubMed

Maldonado, María C; Belfiore, Carolina; Navarro, Antonio R

2008-02-01

Alicyclobacillus acidoterrestris is a thermoacidophilic, non-pathogenic, spore-forming bacterium detected in spoiled commercial pasteurized fruit juice. Apple, white grape and tomato are particularly susceptible. A. acidoterrestris spores are resistant to lemon juice pasteurization (2 min at 82 degrees C), and they can germinate and grow causing spoilage. This contamination is characterized by a medicinal or disinfectant smell attributed to guaiacol (o-dihydroxybenzene) production and other taint chemicals. The aim of this work was to study the influence of temperature (82, 86, 92 and 95 degrees C), total soluble solids (SS) (6.20, 9.8, 50 and 68 degrees Brix) and pH (2.28, 2.45, 2.80, 3.25, 3.5) on decimal reduction time (D) of the A. acidoterrestris in clarified and non-clarified concentrated lemon juice. Once D-value was determined, the resistance of A. acidoterrestris at the assayed temperatures was confirmed. SS and pH influence spore viability, because spore resistance increases with higher SS (50 degrees Brix 22 min 82 degrees C-68 degrees Brix 28 min 82 degrees C) and pH values (pH 2.28, 17 min-pH 4.00, 22 min). Bacterial growth was lower in clarified lemon juice, 26 min at 82 degrees C, than in non-clarified lemon juice, 51 min at 82 degrees C. Temperature was the parameter that had the greatest influence on the D value.

Production and Quality Evaluation of Pineapple Fruit Wine

NASA Astrophysics Data System (ADS)

Qi, Ningli; Ma, Lina; Li, Liuji; Gong, Xiao; Ye, Jianzhi

2017-12-01

The fermentation process of pineapple fruit wine was studied. The juice was inoculated with 5% (v/v) active yeast and held at 20 °C for 7 days. Total sugar and pH decreased while the alcoholic strength increased with increasing length of fermentation. The fermented fruit wine contains 2.29 g/L total acid, 10.2 % (v/v) alcohol, 5.4 °Brix soluble solids, pH 3.52. Pineapple wine detected 68 kinds of aroma components, including 34 esters, 13 alcohols. The ester material accounted for 52.25% of the main aroma components. The quality and sensory evaluation results indicated that pineapple fruit wine belongs to a kind of low alcohol wine, so it is easy to be accepted by the public.

Characterization of pH-fractionated humic acids with respect to their dissociation behaviour.

PubMed

Klučáková, Martina

2016-04-01

Humic acids were divided into several fractions using buffer solutions as extraction agents with different pH values. Two methods of fractionation were used. The first one was subsequent dissolution of bulk humic acids in buffers adjusted to different pH. The second one was sequential dissolution in buffers with increasing pH values. Experimental data were compared with hypothesis of partial solubility of humic acids in aqueous solutions. Behaviour of humic fractions obtained by sequential dissolution, original bulk sample and residual fractions obtained by subsequent dissolution at pH 10 and 12 agrees with the hypothesis. Results demonstrated that regardless the common mechanism, solubility and dissociation degree of various humic fractions may be very different and can be estimated using parameters of the model based on the proposed mechanism. Presented results suggest that dissolving of solid humic acids in water environment is more complex than conventional solubility behaviour of sparingly soluble solids.

Statistical investigation of simulated fed intestinal media composition on the equilibrium solubility of oral drugs.

PubMed

Zhou, Zhou; Dunn, Claire; Khadra, Ibrahim; Wilson, Clive G; Halbert, Gavin W

2017-03-01

Gastrointestinal fluid is a complex milieu and it is recognised that gut drug solubility is different to that observed in simple aqueous buffers. Simulated gastrointestinal media have been developed covering fasted and fed states to facilitate in vitro prediction of gut solubility and product dissolution. However, the combination of bile salts, phospholipids, fatty acids and proteins in an aqueous buffered system creates multiple phases and drug solubility is therefore a complex interaction between these components, which may create unique environments for each API. The impact on solubility can be assessed through a statistical design of experiment (DoE) approach, to determine the influence and relationships between factors. In this paper DoE has been applied to fed simulated gastrointestinal media consisting of eight components (pH, bile salt, lecithin, sodium oleate, monoglyceride, buffer, salt and pancreatin) using a two level D-optimal design with forty-four duplicate measurements and four centre points. The equilibrium solubility of a range of poorly soluble acidic (indomethacin, ibuprofen, phenytoin, valsartan, zafirlukast), basic (aprepitant, carvedilol, tadalafil, bromocriptine) and neutral (fenofibrate, felodipine, probucol, itraconazole) drugs was investigated. Results indicate that the DoE provides equilibrium solubility values that are comparable to literature results for other simulated fed gastrointestinal media systems or human intestinal fluid samples. For acidic drugs the influence of pH predominates but other significant factors related to oleate and bile salt or interactions between them are present. For basic drugs pH, oleate and bile salt have equal significance along with interactions between pH and oleate and lecithin and oleate. Neutral drugs show diverse effects of the media components particularly with regard to oleate, bile salt, pH and lecithin but the presence of monoglyceride, pancreatin and buffer have significant but smaller effects on solubility. There are fourteen significant interactions between factors mainly related to the surfactant components and pH, indicating that the solubility of neutral drugs in fed simulated media is complex. The results also indicate that the equilibrium solubility of each drug can exhibit individualistic behaviour associated with the drug's chemical structure, physicochemical properties and interaction with media components. The utility of DoE for fed simulated media has been demonstrated providing equilibrium solubility values comparable with similar in vitro systems whilst also providing greater information on the influence of media factors and their interactions. The determination of a drug's gastrointestinal solubility envelope provides useful limits that can potentially be applied to in silico modelling and in vivo experiments. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Effects of Low pH on Photosynthesis, Related Physiological Parameters, and Nutrient Profiles of Citrus

PubMed Central

Long, An; Zhang, Jiang; Yang, Lin-Tong; Ye, Xin; Lai, Ning-Wei; Tan, Ling-Ling; Lin, Dan; Chen, Li-Song

2017-01-01

Seedlings of “Xuegan” (Citrus sinensis) and “Sour pummelo” (Citrus grandis) were irrigated daily with a nutrient solution at a pH of 2.5, 3, 4, 5, or 6 for 9 months. Thereafter, the following responses were investigated: seedling growth; root, stem, and leaf concentrations of nutrient elements; leaf gas exchange, pigment concentration, ribulose-1,5-bisphosphate carboxylase/oxygenase activity and chlorophyll a fluorescence; relative water content, total soluble protein level, H2O2 production and electrolyte leakage in roots and leaves. This was done (a) to determine how low pH affects photosynthesis, related physiological parameters, and mineral nutrient profiles; and (b) to understand the mechanisms by which low pH may cause a decrease in leaf CO2 assimilation. The pH 2.5 greatly inhibited seedling growth, and many physiological parameters were altered only at pH 2.5; pH 3 slightly inhibited seedling growth; pH 4 had almost no influence on seedling growth; and seedling growth and many physiological parameters reached their maximum at pH 5. No seedlings died at any given pH. These results demonstrate that citrus survival is insensitive to low pH. H+-toxicity may directly damage citrus roots, thus affecting the uptake of mineral nutrients and water. H+-toxicity and a decreased uptake of nutrients (i.e., nitrogen, phosphorus, potassium, calcium, and magnesium) and water were likely responsible for the low pH-induced inhibition of growth. Leaf CO2 assimilation was inhibited only at pH 2.5. The combinations of an impaired photosynthetic electron transport chain, increased production of reactive oxygen species, and decreased uptake of nutrients and water might account for the pH 2.5-induced decrease in CO2 assimilation. Mottled bleached leaves only occurred in the pH 2.5-treated C. grandis seedlings. Furthermore, the pH 2.5-induced alterations of leaf CO2 assimilation, water-use efficiency, chlorophylls, polyphasic chlorophyll a fluorescence (OJIP) transients and many fluorescence parameters, root and leaf total soluble proteins, H2O2 production, and electrolyte leakage were all slightly greater in C. grandis than in C. sinensis seedlings. Hence, C. sinensis was slightly more tolerant to low pH than C. grandis. In conclusion, our findings provide novel insight into the causes of low pH-induced inhibition of seedling growth and leaf CO2 assimilation. PMID:28270819

Effects of Low pH on Photosynthesis, Related Physiological Parameters, and Nutrient Profiles of Citrus.

PubMed

Long, An; Zhang, Jiang; Yang, Lin-Tong; Ye, Xin; Lai, Ning-Wei; Tan, Ling-Ling; Lin, Dan; Chen, Li-Song

2017-01-01

Seedlings of "Xuegan" ( Citrus sinensis ) and "Sour pummelo" ( Citrus grandis ) were irrigated daily with a nutrient solution at a pH of 2.5, 3, 4, 5, or 6 for 9 months. Thereafter, the following responses were investigated: seedling growth; root, stem, and leaf concentrations of nutrient elements; leaf gas exchange, pigment concentration, ribulose-1,5-bisphosphate carboxylase/oxygenase activity and chlorophyll a fluorescence; relative water content, total soluble protein level, H 2 O 2 production and electrolyte leakage in roots and leaves. This was done ( a ) to determine how low pH affects photosynthesis, related physiological parameters, and mineral nutrient profiles; and ( b ) to understand the mechanisms by which low pH may cause a decrease in leaf CO 2 assimilation. The pH 2.5 greatly inhibited seedling growth, and many physiological parameters were altered only at pH 2.5; pH 3 slightly inhibited seedling growth; pH 4 had almost no influence on seedling growth; and seedling growth and many physiological parameters reached their maximum at pH 5. No seedlings died at any given pH. These results demonstrate that citrus survival is insensitive to low pH. H + -toxicity may directly damage citrus roots, thus affecting the uptake of mineral nutrients and water. H + -toxicity and a decreased uptake of nutrients (i.e., nitrogen, phosphorus, potassium, calcium, and magnesium) and water were likely responsible for the low pH-induced inhibition of growth. Leaf CO 2 assimilation was inhibited only at pH 2.5. The combinations of an impaired photosynthetic electron transport chain, increased production of reactive oxygen species, and decreased uptake of nutrients and water might account for the pH 2.5-induced decrease in CO 2 assimilation. Mottled bleached leaves only occurred in the pH 2.5-treated C. grandis seedlings. Furthermore, the pH 2.5-induced alterations of leaf CO 2 assimilation, water-use efficiency, chlorophylls, polyphasic chlorophyll a fluorescence (OJIP) transients and many fluorescence parameters, root and leaf total soluble proteins, H 2 O 2 production, and electrolyte leakage were all slightly greater in C. grandis than in C. sinensis seedlings. Hence, C. sinensis was slightly more tolerant to low pH than C. grandis . In conclusion, our findings provide novel insight into the causes of low pH-induced inhibition of seedling growth and leaf CO 2 assimilation.

Welding fumes from stainless steel gas metal arc processes contain multiple manganese chemical species.

PubMed

Keane, Michael; Stone, Samuel; Chen, Bean

2010-05-01

Fumes from a group of gas metal arc welding (GMAW) processes used on stainless steel were generated using three different metal transfer modes and four different shield gases. The objective was to identify and measure manganese (Mn) species in the fumes, and identify processes that are minimal generators of Mn species. The robotic welding system was operated in short-circuit (SC) mode (Ar/CO2 and He/Ar), axial spray (AXS) mode (Ar/O2 and Ar/CO2), and pulsed axial-spray (PAXS) mode (Ar/O2). The fumes were analyzed for Mn by a sequential extraction process followed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis, and by X-ray diffraction (XRD). Total elemental Mn, iron (Fe), chromium (Cr) and nickel (Ni) were separately measured after aqua regia digestion and ICP-AES analysis. Soluble Mn2+, Fe2+, Fe3+, and Ni2+ in a simple biological buffer (phosphate-buffered saline) were determined at pH 7.2 and 5.0 after 2 h incubation at 37 C by ion chromatography. Results indicate that Mn was present in soluble form, acid-soluble form, and acid-soluble form after reduction by hydroxylamine, which represents soluble Mn0 and Mn2+ compounds, other Mn2+ compounds, and (Mn3+ and Mn4+) compounds, respectively. The dominant fraction was the acid-soluble Mn2+ fraction, but results varied with the process and shield gas. Soluble Mn mass percent in the fume ranged from 0.2 to 0.9%, acid-soluble Mn2+ compounds ranged from 2.6 to 9.3%, and acid plus reducing agent-soluble (Mn3+ and Mn4+) compounds ranged from 0.6 to 5.1%. Total Mn composition ranged from 7 to 15%. XRD results showed fumes had a crystalline content of 90-99% Fe3O4, and showed evidence of multiple Mn oxides, but overlaps and weak signals limited identification. Small amounts of the Mn2+ in the fume (<0.01 to ≈ 1% or <0.1 to ≈ 10 microg ml(-1)) and Ni2+ (<0.01 to ≈ 0.2% or <0.1 to ≈ 2 mg ml(-1)) ions were found in biological buffer media, but amounts were highly dependent on pH and the welding process. Mn generation rates for the fractions were tabulated, and the influence of ozone is discussed. The conclusions are that exposures to welding fumes include multiple Mn species, both soluble and insoluble, and that exposures to Mn species vary with specific processes and shield gases.

Trace elements in urban and suburban rainfall, Mersin, Northeastern Mediterranean

NASA Astrophysics Data System (ADS)

Özsoy, Türkan; Örnektekin, Sermin

2009-10-01

Spatial/temporal variabilities of rainwater constituents are examined based on soluble/insoluble trace elements, pH and electrical conductivity measurements in rainfall sampled during December 2003-May 2005 at two urban and two suburban sites in Mersin, an industrialized city of 850,000 inhabitants on the southern coast of Turkey. In the analyses, backward air mass trajectories for rainy days were used in addition to factor analyses, enrichment factors, phase distributions and correlations between trace elements. The pH varied from 4.8 to 8.5 with an average value of 6.2, reflecting a mainly alkaline regime. Mean concentrations of trace elements collected from urban and suburban sites are spatially variable. Based on the overall data, total concentrations of trace elements were ordered as Ca > Na > Fe > Al > Mg > K > Zn > Mn > Sr > Pb > Ni > Cr > Ba > Cu > Co > Cd. Mainly terrigeneous (Ca, Fe, Al) and, to a lesser extent, sea salt particles (Na, Mg) were shown to be the major source of trace elements. Excluding major cations, the solubilities of trace elements were found to be ordered as Sr > Zn > Ba > Mn > Cu > Ni > Cr > Fe > Al, confirming the lower solubility of crustal elements. Cd, Co and Pb were excluded from the above evaluation because of the low numbers of soluble samples allowing quantitative measurements. The solubilities of Al, Fe, Mn and particularly of Ni were found to be considerably lower than those reported for various sites around the world, most likely due to the effect of pH. During the entire sampling period, a total of 28 dust transport episodes associated with 31 red rain events were identified. Extremely high mean concentration ratios of Al (8.2), Fe (14.4) and Mn (13.1) were observed in red rain, compared to normal rain. The degree of this enhancement displayed a decrease from crustal to anthropogenic origin elements and the lowest enhancements were found for anthropogenic origin elements of Zn and Cd (both having a ratio of 1.1). Aerosol dust was found to be the main source of almost all analyzed elements in Mersin precipitation, regardless that they are crustal or anthropic derived elements. The magnitude of crustal source contribution to trace element budget of precipitation was at its highest levels for crustal originated elements, most probably due to much higher scavenging ratios of crustal elements compared to anthropogenic ones.

Studies on jicama juice processing.

PubMed

Juarez, M S; Paredes-Lopez, O

1994-09-01

Juice was extracted from jicama (Pachyrrizus erosus Urban) and clarified using a 10,000 daltons molecular weight cut-off membrane to improve its stability. Ultrafiltered juice was tested for general composition and Hunter color. Ultrafiltration (UF) retentate and UF permeate showed some changes, compared to fresh juice, in total and soluble solids, total sugars, and nitrogen, whereas ash and pH remained constant. Hunter color of juice samples exhibited some variation by UF. Results suggest that UF has potential to produce jicama juice with desirable and stable aroma and flavor.

Effects of pH and Temperature on the Stability of Fumonisins in Maize Products.

PubMed

Bryła, Marcin; Waśkiewicz, Agnieszka; Szymczyk, Krystyna; Jędrzejczak, Renata

2017-03-01

This paper is a study of the stability of fumonisins in dough based on maize flour prepared in a phosphate buffer with a pH of 3.5, 5.5 or 7.5 and baked at a temperature within the range of 100-250 °C. Buffers with various pH values were tested, since it is well-known that pH may significantly influence interactions of fumonisins with other substances. A standard analytical procedure was used to determine the concentration of free fumonisins. Hydrolysis in an alkaline medium was then applied to reveal the hidden forms, while the total fumonisins concentations was determined in another measurement. The total concentration of fumonisins was statistically higher in pH = 3.5 and pH = 5.5 than the concentration of free fumonisins; no similar difference was found at pH = 7.5. The applied phosphate buffer pH 7.5 may enhance solubility of fumonisins, which would increase extraction efficiency of free analytes, thereby decreasing the difference between concentrations of total and free fumonisins. Hydrolysed B₁ fumonisin (HFB₁) and partially hydrolysed B₁ fumonisin (isomers a and b: PHFB 1a and PHFB 1b , respectively) were the main investigated substances. For baking temperatures below 220 °C, fumonisins were slightly more stable for pH = 5.5 than for pH = 3.5 and pH = 7.5. In both of these latter cases, the concentration of partially hydrolysed fumonisins grew initially (up to 200 °C) with an increase in the baking temperature, and then dropped. Similar behaviour was observed for free HFB₁, which may suggest the following fumonisin degradation mechanism: initially, the tricarballylic acid (TCA) groups are removed from the molecules, and next, the HFB₁ molecules disintegrate.

Effects of pH and Temperature on the Stability of Fumonisins in Maize Products

PubMed Central

Bryła, Marcin; Waśkiewicz, Agnieszka; Szymczyk, Krystyna; Jędrzejczak, Renata

2017-01-01

This paper is a study of the stability of fumonisins in dough based on maize flour prepared in a phosphate buffer with a pH of 3.5, 5.5 or 7.5 and baked at a temperature within the range of 100–250 °C. Buffers with various pH values were tested, since it is well-known that pH may significantly influence interactions of fumonisins with other substances. A standard analytical procedure was used to determine the concentration of free fumonisins. Hydrolysis in an alkaline medium was then applied to reveal the hidden forms, while the total fumonisins concentations was determined in another measurement. The total concentration of fumonisins was statistically higher in pH = 3.5 and pH = 5.5 than the concentration of free fumonisins; no similar difference was found at pH = 7.5. The applied phosphate buffer pH 7.5 may enhance solubility of fumonisins, which would increase extraction efficiency of free analytes, thereby decreasing the difference between concentrations of total and free fumonisins. Hydrolysed B1 fumonisin (HFB1) and partially hydrolysed B1 fumonisin (isomers a and b: PHFB1a and PHFB1b, respectively) were the main investigated substances. For baking temperatures below 220 °C, fumonisins were slightly more stable for pH = 5.5 than for pH = 3.5 and pH = 7.5. In both of these latter cases, the concentration of partially hydrolysed fumonisins grew initially (up to 200 °C) with an increase in the baking temperature, and then dropped. Similar behaviour was observed for free HFB1, which may suggest the following fumonisin degradation mechanism: initially, the tricarballylic acid (TCA) groups are removed from the molecules, and next, the HFB1 molecules disintegrate. PMID:28257053

In Situ Bioremediation of Chlorinated Solvents Source Areas with Enhanced Mass Transfer

DTIC Science & Technology

2009-11-01

cells within NAPL Area 3 ................................. 22 Figure 6. Impact of whey injection on pH in the treatment cells...locations following 1% and 10% whey injections. ............................ 39 Figure 12. Total chlorinated ethene concentration contours at select time...points. ................ 40 Figure 13. Relationship between interfacial tension reduction and enhanced solubility of TCE DNAPL as a function of whey

Optimisation of microwave-assisted processing in production of pineapple jam

NASA Astrophysics Data System (ADS)

Ismail, Nur Aisyah Mohd; Abdullah, Norazlin; Muhammad, Norhayati

2017-10-01

Pineapples are available all year round since they are unseasonal fruits. Due to the continuous harvesting of the fruit, the retailers and farmers had to find a solution such as the processing of pineapple into jam, to treat the unsuccessfully sold pineapples. The direct heating of pineapple puree during the production of pineapple jam can cause over degradation of quality of the fresh pineapple. Thus, this study aims to optimise the microwave-assisted processing conditions for producing pineapple jam which could reduce water activity and meets minimum requirement for pH and total soluble solids contents of fruit jam. The power and time of the microwave processing were chosen as the factors, while the water activity, pH and total soluble solids (TSS) content of the pineapple jam were determined as responses to be optimised. The microwave treatment on the pineapple jam was able to give significant effect on the water activity and TSS content of the pineapple jam. The optimum power and time for the microwave processing of pineapple jam is 800 Watt and 8 minutes, respectively. The use of domestic microwave oven for the pineapple jam production results in acceptable pineapple jam same as conventional fruit jam sold in the marketplace.

Extraction, composition, and functional properties of dried alfalfa (Medicago sativa L.) leaf protein.

PubMed

Hojilla-Evangelista, Mila P; Selling, Gordon W; Hatfield, Ronald; Digman, Matthew

2017-02-01

Alfalfa is considered a potential feedstock for biofuels; co-products with value-added uses would enhance process viability. This work evaluated dried alfalfa leaves for protein production and describes the functional properties of the protein. Dried alfalfa leaves contained 260 g kg -1 dry basis (DB) crude protein, with albumins being the major fraction (260 g kg -1 of total protein). Alkali solubilization for 2 h at 50 °C, acid precipitation, dialysis, and freeze-drying produced a protein concentrate (600 g kg -1 DB crude protein). Alfalfa leaf protein concentrate showed moderate solubility (maximum 500 g kg -1 soluble protein from pH 5.5 to 10), excellent emulsifying properties (activity 158-219 m 2  g -1 protein, stability 17-49 min) and minimal loss of solubility during heating at pH ≥ 7.0. It is technically feasible to extract protein with desirable emulsifying and heat stability properties from dried alfalfa leaves; however, the dried form may not be a practical starting material for protein production, given the difficulty of achieving high yields and high-purity protein product. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Estimation of intragastric solubility of drugs: in what medium?

PubMed

Vertzoni, Maria; Pastelli, Eleni; Psachoulias, Dimitris; Kalantzi, Lida; Reppas, Christos

2007-05-01

To measure the solubility of four drugs in human gastric aspirates, canine gastric aspirates (CGF) and simulated gastric fluids in order to propose a medium for estimating intragastric drug solubility relevant to a bioavailability study in the fasted state. Intragastric environment after administration of water to healthy fasted adults and to healthy fasted dogs (this study) was initially characterized. Solubilities were then measured with the shake-flask method in gastric fluid aspirated after the administration of water to healthy fasted adults and to healthy fasted dogs, in various simulated gastric fluids, i.e. SGF(SLS), SGF(Triton), FaSSGF, FaSSGF(NaCl), and in various HCl solutions with pH values ranging from 1.2 to 2.9. In all cases, FaSSGF performed better than canine aspirates, SGF(SLS), SGF(Triton), or FaSSGF(NaCl) in predicting solubility in HGF. However, its superiority over HCl pH 1.6 was not clear. For ketoconazole, dipyridamole, miconazole, and felodipine deviations of solubility data in FaSSGF from solubility data in HGF were non-significant, 34, -39 and 252%, respectively, whereas the corresponding deviations of data in HCl pH 1.6 from data in HGF were non-significant, 24, 70, and 130%, respectively. Combining data in FaSSGF and HCl pH 1.6 is comparatively the most efficient way to get an estimate of drug solubility in the fasting gastric contents during a bioavailability study. However, accurate estimation of intragastric solubility is limited by the changing environment during intragastric residence of solid particles and the degree of simulation of intragastric composition.

Role of the cultivar in choosing Clementine fruits with a high level of health-promoting compounds.

PubMed

Milella, Luigi; Caruso, Marisa; Galgano, Fernanda; Favati, Fabio; Padula, Maria Carmela; Martelli, Giuseppe

2011-05-25

Thirteen cultivars and two hybrids of Clementine fruits (Citrus clementina Hort. Ex. Tan) cultivated in Italy were characterized according to pH, titratable acidity, total soluble solids, total polyphenols, carotenoids, vitamin C, hesperidin, rutin, narirutin and naringin and radical scavenging activity. The presence of rutin in Clementine fruit juice is reported for the first time here. The results indicated that all chemical parameters statistically differentiated each cultivar (P < 0.001). In particular, principal component analysis showed a clear discrimination of five cultivars from all the other varieties based on vitamin C and total polyphenols for the Caffin cultivar, which showed also the highest antioxidant activity; narirutin for the Etna hybrid cultivar; hesperidin, rutin and total soluble solids for the SRA 89 cultivar; and naringin, hesperidin and rutin for the Esbal cultivar. Moreover, the Mandalate hybrid cultivar showed the lowest antioxidant activity as well as vitamin C and total polyphenols content, while titratable acidity and naringin level were the highest. The antioxidant activity assessed in all the fruits was closely correlated with vitamin C and total polyphenols content, rather than with the flavonoid compounds.

Simultaneous production of 2,3-butanediol, ethanol and hydrogen with a Klebsiella sp. strain isolated from sewage sludge.

PubMed

Wu, Ken-Jer; Saratale, Ganesh D; Lo, Yung-Chung; Chen, Wen-Ming; Tseng, Ze-Jing; Chang, Ming-Ching; Tsai, Ben-Ching; Su, Ay; Chang, Jo-Shu

2008-11-01

A Klebsiella sp. HE1 strain isolated from hydrogen-producing sewage sludge was examined for its ability to produce H2 and other valuable soluble metabolites (e.g., ethanol and 2,3-butanediol) from sucrose-based medium. The effect of pH and carbon substrate concentration on the production of soluble and gaseous products was investigated. The major soluble metabolite produced from Klebsiella sp. HE1 was 2,3-butanediol, accounting for over 42-58% of soluble microbial products (SMP) and its production efficiency enhanced after increasing the initial culture pH to 7.3 (without pH control). The HE1 strain also produced ethanol (contributing to 29-42% of total SMP) and a small amount of lactic acid and acetic acid. The gaseous products consisted of H2 (25-36%) and CO2 (64-75%). The optimal cumulative hydrogen production (2.7 l) and hydrogen yield (0.92mol H2 mol sucrose(-1)) were obtained at an initial sucrose concentration of 30g CODl(-1) (i.e., 26.7gl(-1)), which also led to the highest production rate for H2 (3.26mmol h(-1)l(-1)), ethanol (6.75mmol h(-1)l(-1)) and 2,3-butanediol (7.14mmol h(-1)l(-1)). The highest yield for H2, ethanol and 2,3-butanediol was 0.92, 0.81 and 0.59molmol-sucrose(-1), respectively. As for the overall energy production performance, the highest energy generation rate was 27.7kJ h(-1)l(-1) and the best energy yield was 2.45kJmolsucrose(-1), which was obtained at a sucrose concentration of 30 and 20g CODl(-1), respectively.

Determining total phenolic content and total antioxidant capacity of loquat cultivars grown in Hatay

PubMed Central

Polat, A. Aytekin; Çalişkan, Oğuzhan; Serçe, Sedat; Saraçoğlu, Onur; Kaya, Cemal; Özgen, Mustafa

2010-01-01

Several fruit characteristics of five loquat (Eriobotrya japonica (Thunb.) Lindl.) cultivars/selections grown in Dörtyol, Hatay, Turkey were investigated in 2008. The cultivars/selections included ‘Baduna 5’, Güzelyurt 1, ‘Hafif Çukurgöbek’, ‘Ottaviani,’ and Type 1. The characteristics evaluated included fruit weight, width, length, seed number and weight, flesh/seed ratio, total soluble solids (TSS), pH, acidity, total phenolic (TP) content, and total antioxidant capacity (TAC), determined by the ferric reducing antioxidant power (FRAP) assay. The analyses were conducted by three replicates, with 30 fruits in each replicate. The results indicated that there were significant differences among the cultivars, for all the traits tested. For example, ‘Hafif Çukurgöbek’ and ‘Ottaviani’ had smaller fruits than others, although ‘Hafif Çukurgöbek’ had heavier seeds. The flesh/seed ratio was the highest in Type 1, while ‘Hafif Çukurgöbek’ had the highest pH and high soluble solids. ‘Baduna 5’ and ‘Hafif Çukurgöbek’ had the highest acidity. The TP ranged from 129 (‘Baduna 5’) to 578 (‘Hafif Çukurgöbek’) mg gallic acid equivalent (GAE)/kg fresh fruit (fw). ‘Hafif Çukurgöbek’ also had the highest FRAP mean (12.1 mmol Trolox Equivalent (TE)/kg fw). The results suggest that loquat cultivars have a variable range of TP content and a relatively high total antioxidant capacity, which is crucial for human health. PMID:20548929

Automatic pH Control and Soluble and Insoluble Substrate Input for Continuous Culture of Rumen Microorganisms

PubMed Central

Slyter, Leonard L.

1975-01-01

An artifical rumen continuous culture with pH control, automated input of water-soluble and water-insoluble substrates, controlled mixing of contents, and a collection system for gas is described. Images PMID:16350029

Drugs in breast milk.

PubMed

Hervada, A R; Feit, E; Sagraves, R

1978-09-01

The amount of drug excreted into breast milk is dependent upon the lipid solubility of the medication, the mechanism of transport, the degree of ionization, and change in plasma pH. The higher the lipid solubility, the greater the concentration in human milk. The majority of drugs are transported into mammary blood capillaries by passive diffusion. The rest are transported by reverse pinocytosis. Once the drug has entered the epithelial cells of breast tissue, the drug molecules are excreted into the human milk by active transport, passive diffusion, or apocrine secretion. The amount of free (active) drug available for transport depends on the degree of protein binding the plasma pH. Another factor affecting excretion of drugs is the time when breast feeding occurs. In the 1st few days of life, when colostrum is present, water-soluble drugs pass through the breast more easily than afterwards when milk is produced. Then lipid-soluble drugs cross in higher concentrations. The effect on nursing infants is dependent on the amount excreted into the milk, the total amount absorbed by the infant, and the toxicity of the drug. The use of the following drugs in breast feeding mothers is reviewed: anticoagulants, antihypertensives and diuretics, antimicrobials, drugs affecting the central nervous system (alcohol, chloral hydrate, meprobamate, lithium, and aspirin), marijuana, other drugs (antihistamines, atropine, ergot alkaloids, laxatives, nicotine, iodides, propylthiouracil, theophylline), hormones (insulin, thyroxine, and oral contraceptives), and radiopharmaceuticals.

Intermolecular binding of blueberry pectin-rich fractions and anthocyanin.

PubMed

Lin, Z; Fischer, J; Wicker, L

2016-03-01

Pectin was extracted from blueberry powder into three fractions of water soluble (WSF), chelator soluble (CSF) and sodium carbonate soluble (NSF). The fractions were incubated with cyanidin-3-glucoside (C3G), a mixture of five anthocyanidins (cyanidin, pelargonidin, malvidin, petunidin and delphinidin) or blueberry juice at pH 2.0-4.5. Free anthocyanins and bound anthocyanin-pectin mixtures were separated by ultrafiltration. WSF bound the least amount of anthocyanin at all pH values. CSF had stronger anthocyanin binding ability at pH 2.0-3.6, while NSF had stronger anthocyanin binding ability at pH 3.6-4.5. The pectin and anthocyanin binding was lowest at pH 4.5 and higher at pH 2.0-3.6. Nearly doubling C3G pigment content increased bound anthocyanin percentage by 16-23% at pH 3.6, which favored anthocyanin aromatic stacking, compared to 3-9% increase at pH 2.0. Ionic interaction between anthocyanin flavylium cations and free pectic carboxyl groups, and anthocyanin stacking may be two major mechanisms for pectin and anthocyanin binding. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prediction of pH dependent absorption using in vitro, in silico, and in vivo rat models: Early liability assessment during lead optimization.

PubMed

Saxena, Ajay; Shah, Devang; Padmanabhan, Shweta; Gautam, Shashyendra Singh; Chowan, Gajendra Singh; Mandlekar, Sandhya; Desikan, Sridhar

2015-08-30

Weakly basic compounds which have pH dependent solubility are liable to exhibit pH dependent absorption. In some cases, a subtle change in gastric pH can significantly modulate the plasma concentration of the drug and can lead to sub-therapeutic exposure of the drug. Evaluating the risk of pH dependent absorption and potential drug-drug interaction with pH modulators are important aspects of drug discovery and development. In order to assess the risk around the extent of decrease in the systemic exposure of drugs co-administered with pH modulators in the clinic, a pH effect study is carried out, typically in higher species, mostly dog. The major limitation of a higher species pH effect study is the resource and material requirement to assess this risk. Hence, these studies are mostly restricted to promising or advanced leads. In our current work, we have used in vitro aqueous solubility, in silico simulations using GastroPlus™ and an in vivo rat pH effect model to provide a qualitative assessment of the pH dependent absorption liability. Here, we evaluate ketoconazole and atazanavir with different pH dependent solubility profiles and based on in vitro, in silico and in vivo results, a different extent of gastric pH effect on absorption is predicted. The prediction is in alignment with higher species and human pH effect study results. This in vitro, in silico and in vivo (IVISIV) correlation is then extended to assess pH absorption mitigation strategy. The IVISIV predicts pH dependent absorption for BMS-582949 whereas its solubility enhancing prodrug, BMS-751324 is predicted to mitigate this liability. Overall, the material requirement for this assessment is substantially low which makes this approach more practical to screen multiple compounds during lead optimization. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of pH on thermal stability of collagen in the dispersed and aggregated states (Short Communication)

PubMed Central

Russell, Allan E.

1974-01-01

Thermal stabilities of mature insoluble collagen, salt-precipitated fibrils of acid-soluble collagen and acid-soluble collagen in solution were compared as a function of acid pH. Both insoluble and precipitated collagens showed large parallel destabilization with decrease in pH, whereas the intrinsic stability of individual collagen molecules in dilute solution was comparatively unaffected. PMID:4478066

Bioavailability enhancement of a poorly water-soluble drug by solid dispersion in polyethylene glycol-polysorbate 80 mixture.

PubMed

Joshi, Hemant N; Tejwani, Ravindra W; Davidovich, Martha; Sahasrabudhe, Vaishali P; Jemal, Mohammed; Bathala, Mohinder S; Varia, Sailesh A; Serajuddin, Abu T M

2004-01-09

Oral bioavailability of a poorly water-soluble drug was greatly enhanced by using its solid dispersion in a surface-active carrier. The weakly basic drug (pK(a) approximately 5.5) had the highest solubility of 0.1mg/ml at pH 1.5, < 1 microg/ml aqueous solubility between pH 3.5 and 5.5 at 24+/-1 degrees C, and no detectable solubility (< 0.02 microg/ml) at pH greater than 5.5. Two solid dispersion formulations of the drug, one in Gelucire 44/14 and another one in a mixture of polyethylene glycol 3350 (PEG 3350) with polysorbate 80, were prepared by dissolving the drug in the molten carrier (65 degrees C) and filling the melt in hard gelatin capsules. From the two solid dispersion formulations, the PEG 3350-polysorbate 80 was selected for further development. The oral bioavailability of this formulation in dogs was compared with that of a capsule containing micronized drug blended with lactose and microcrystalline cellulose and a liquid solution in a mixture of PEG 400, polysorbate 80 and water. For intravenous administration, a solution in a mixture of propylene glycol, polysorbate 80 and water was used. Absolute oral bioavailability values from the capsule containing micronized drug, the capsule containing solid dispersion and the oral liquid were 1.7+/-1.0%, 35.8+/-5.2% and 59.6+/-21.4%, respectively. Thus, the solid dispersion provided a 21-fold increase in bioavailability of the drug as compared to the capsule containing micronized drug. A capsule formulation containing 25 mg of drug with a total fill weight of 600 mg was subsequently selected for further development. The selected solid dispersion formulation was physically and chemically stable under accelerated storage conditions for at least 6 months. It is hypothesized that polysorbate 80 ensures complete release of drug in a metastable finely dispersed state having a large surface area, which facilitates further solubilization by bile acids in the GI tract and the absorption into the enterocytes. Thus, the bioavailability of this poorly water-soluble drug was greatly enhanced by formulation as a solid dispersion in a surface-active carrier.

Effects of a low severity prescribed fire on water-soluble elements in ash from a cork oak (Quercus suber) forest located in the northeast of the Iberian Peninsula

USGS Publications Warehouse

Pereira, P.; beda, X.; Martin, D.; Mataix-Solera, J.; Guerrero, C.

2011-01-01

Wildfire is the major disturbance in Mediterranean forests. Prescribed fire can be an alternative to reduce the amount of fuel and hence decrease the wildfire risk. However the effects of prescribed fire must be studied, especially on ash properties, because ash is an important nutrient source for ecosystem recovery. The aim of this study is to determine the effects of a low severity prescribed fire on water-soluble elements in ash including pH, electrical conductivity (EC), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), aluminum (Al), manganese (Mn), iron (Fe), zinc (Zn), silica (SiO2) and total sulphur (TS). A prescribed fire was conducted in a cork oak (Quercus suber) (Q.S) forest located in the northeast part of the Iberian Peninsula. Samples were collected from a flat plot of 40??70m mainly composed of Q.S and Quercus robur (Q.R) trees. In order to understand the effects of the prescribed fire on the soluble elements in ash, we conducted our data analysis on three data groups: all samples, only Q.S samples and only Q.R samples. All three sample groups exhibited a significant increase in pH, EC (p<0.001), water-soluble Ca, Mg, Na, SiO2 and TS and a decrease in water-soluble Mn, Fe and Zn. Differences were identified between oak species for water-soluble K, Al and Fe. In Q.S samples we registered a significant increase in the first two elements p<0.001 and p<0.01, respectively, and a non-significant impact in the third, at p<0.05. In Q.R data we identified a non-significant impact on water-soluble K and Al and a significant decrease in water-soluble Fe (p<0.05). These differences are probably due to vegetation characteristics and burn severity. The fire induced a higher variability in the ash soluble elements, especially in Q.S samples, that at some points burned with higher severity. The increase of pH, EC, Ca, Mg, Na and K will improve soil fertility, mainly in the study area where soils are acidic. The application of this low severity prescribed fire will improve soil nutrient status without causing soil degradation and thus is considered to be a good management strategy. ?? 2010 Elsevier Inc.

Effects of a low severity prescribed fire on water-soluble elements in ash from a cork oak (Quercus suber) forest located in the northeast of the Iberian Peninsula.

PubMed

Pereira, Paulo; Ubeda, Xavier; Martin, Deborah; Mataix-Solera, Jorge; Guerrero, César

2011-02-01

Wildfire is the major disturbance in Mediterranean forests. Prescribed fire can be an alternative to reduce the amount of fuel and hence decrease the wildfire risk. However the effects of prescribed fire must be studied, especially on ash properties, because ash is an important nutrient source for ecosystem recovery. The aim of this study is to determine the effects of a low severity prescribed fire on water-soluble elements in ash including pH, electrical conductivity (EC), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), aluminum (Al), manganese (Mn), iron (Fe), zinc (Zn), silica (SiO(2)) and total sulphur (TS). A prescribed fire was conducted in a cork oak (Quercus suber) (Q.S) forest located in the northeast part of the Iberian Peninsula. Samples were collected from a flat plot of 40×70m mainly composed of Q.S and Quercus robur (Q.R) trees. In order to understand the effects of the prescribed fire on the soluble elements in ash, we conducted our data analysis on three data groups: all samples, only Q.S samples and only Q.R samples. All three sample groups exhibited a significant increase in pH, EC (p<0.001), water-soluble Ca, Mg, Na, SiO(2) and TS and a decrease in water-soluble Mn, Fe and Zn. Differences were identified between oak species for water-soluble K, Al and Fe. In Q.S samples we registered a significant increase in the first two elements p<0.001 and p<0.01, respectively, and a non-significant impact in the third, at p<0.05. In Q.R data we identified a non-significant impact on water-soluble K and Al and a significant decrease in water-soluble Fe (p<0.05). These differences are probably due to vegetation characteristics and burn severity. The fire induced a higher variability in the ash soluble elements, especially in Q.S samples, that at some points burned with higher severity. The increase of pH, EC, Ca, Mg, Na and K will improve soil fertility, mainly in the study area where soils are acidic. The application of this low severity prescribed fire will improve soil nutrient status without causing soil degradation and thus is considered to be a good management strategy. Copyright © 2010 Elsevier Inc. All rights reserved.

A recipe for designing water-soluble, beta-sheet-forming peptides.

PubMed Central

Mayo, K. H.; Ilyina, E.; Park, H.

1996-01-01

Based on observations of solubility and folding properties of peptide 33-mers derived from the beta-sheet domains of platelet factor-4 (PF4), interleukin-8 (IL-8), and growth related protein (Gro-alpha), as well as other beta-sheet-forming peptides, general guidelines have been developed to aid in the design of water soluble, self-association-induced beta-sheet-forming peptides. CD, 1H-NMR, and pulsed field gradient NMR self-diffusion measurements have been used to assess the degree of folding and state of aggregation. PF4 peptide forms native-like beta-sheet tetramers and is sparingly soluble above pH 6. IL-8 peptide is insoluble between pH 4.5 and pH 7.5, yet forms stable, native-like beta-sheet dimers at higher pH. Gro-alpha peptide is soluble at all pH values, yet displays no discernable beta-sheet structure even when diffusion data indicate dimer-tetramer aggregation. A recipe used in the de novo design of water-soluble beta-sheet-forming peptides calls for the peptide to contain 40-50% hydrophobic residues, usually aliphatic ones (I, L, V, A, M) (appropriately paired and mostly but not always alternating with polar residues in the sheet sequence), a positively charged (K, R) to negatively charged (E, D) residue ratio between 4/2 and 6/2, and a noncharged polar residue (N, Q, T, S) composition of about 20% or less. Results on four de novo designed, 33-residue peptides are presented supporting this approach. Under near physiologic conditions, all four peptides are soluble, form beta-sheet structures to varying degrees, and self-associate. One peptide folds as a stable, compact beta-sheet tetramer, whereas the others are transient beta-sheet-containing aggregates. PMID:8819163

An analysis on flavonoids, phenolics and organic acids contents in brewed red wines of both non-skin contact and skin contact fermentation techniques of Mao Luang ripe fruits (Antidesma bunius) harvested from Phupan Valley in Northeast Thailand.

PubMed

Samappito, S; Butkhup, L

2008-07-01

The experiment was carried out at the Department of Biotechnology, Faculty of Technology, Mahasarakham University, Northeast Thailand during the 2006. The study aimed to determine amounts of flavonoids, phenolics and organic acids in ripe fruits and brewed red wines of both non-skin contact and skin contact winemaking techniques where Mao Luang ripe fruits of both Fapratan and Sangkrow2 cultivars were used. The experiment was laid in a Completely Randomised Design (CRD) with four replications. The results showed that mean values of primary data of fresh Mao Luang ripe fruits on weight of 100 berries (g) and mean values of juice:solids, pH, total soluble solid (TSS, 0brix), total organic acids (TOA, mg L(-1)), TSS:TOA (%), total flavonoids contents (TFC, mg L(-l)), total phenolic acids (TPA, mg L(-1)), total procyanidins contents (TPC, mg L(-1)) and reducing sugar (g L(-1)) were 65.62, 3.28, 3.51, 16.50, 49.36, 28.10, 397.90, 76.04, 156.21 and 184.32, respectively. Skin contact Mao Luang red wine gave higher amounts of flavonoids, phenolic acids, anthocyanins of procyanidin B1 and procyanidin B2, organic acids than non-skin contact red wine. The differences were highly significant. Furthermore, ethanol (%) and total acidity (g L(-1) citric acid) were much higher for skin contact wine than non-skin contact wine but a reverse was found with total soluble solids (0brix), pH where non-skin contact wine gave higher mean values than skin contact wine.

Seasonal variation of limnological features and trophic state index of two oligotrophic reservoirs of southeast Brazil.

PubMed

Oliveira, S A; Bicudo, C E M

2017-01-01

Limnological features of two reservoirs were studied in dry (August 2013) and rainy (January 2014) periods to evaluate the water quality that supply the city of Guarulhos, southeast Brazil. Water samples were collected in three depths and the following characteristics were measured: alkalinity, dissolved O2, free and total CO2, HCO3, soluble reactive silica, dissolved and total nitrogen and phosphorus, and chlorophyll-a. Water transparency was also measured and temperature, pH and electric conductivity profiles were obtained. Great seasonal and low spatial variability of the water characteristics occurred in the reservoirs. High values of water transparency, free CO2 availability, and low of pH, soluble reactive silica and total and dissolved nutrients values were recorded at the dry period, and different conditions were found at the rainy season. The two reservoirs were characterized by low nutrients, chlorophyll-a and turbidity, and high transparency, these features being typical of oligotrophic systems. The two reservoirs still remain under low anthropogenic impact conditions, and are presently considered reference systems for the SPMR, São Paulo Metropolitan Region. The need for actions that will reduce the input of nutrients from the neighboring cities and the main tributaries of the hydrographic basin is emphasized to maintain the ecological quality of the reservoirs and their reference conditions among the SPRM reservoirs.

Kinetics of ascorbic acid degradation in un-pasteurized Iranian lemon juice during regular storage conditions.

PubMed

Abbasi, A; Niakousari, M

2008-05-15

The aim of this research was to determine shelf life stability of un-pasteurized lemon juice filled in clear or dark green glass bottles. Presence of light, time and temperature affect the ascorbic acid retention in citrus juices. Bottles were stored at room temperature (27 +/- 3 degrees C) and in the refrigerator (3 +/- 1 degrees C). Total soluble solids, total titrable acidity and pH value were measured every three weeks and analysis was carried out on ascorbic acid content by means of titration method in the presence of 2,6-dichlorophenol indophenol. The study was carried out for 12 weeks after which slight changes in color, taste and apparent texture in some samples were observed and ascorbic acid content reduced by 50%. Soluble solids content, pH value and total acidity were 5.5 degrees Brix, 2.73 and 5 g/100 mL, respectively which appeared not to be significantly influenced by storage time or conditions. Ascorbic acid content initially at 38.50 mg/100 mL was sharply reduced to about 22 mg/100 mL within the first three weeks of storage. The final ascorbic acid content of all samples was about 15 mg/100 mL. The deteriorative reaction of ascorbic acid in the juice at all conditions followed a first-order kinetic model with activation energy of 137 cal mol(-1).

Relationships between dry matter content, ensiling, ammonia-nitrogen, and ruminal in vitro starch digestibility in high-moisture corn samples.

PubMed

Ferraretto, L F; Taysom, K; Taysom, D M; Shaver, R D; Hoffman, P C

2014-05-01

The objectives of the study were (1) to determine relationships between high-moisture corn (HMC) dry matter (DM), ammonia-N [% of crude protein (CP)], and soluble CP concentrations, and pH, with 7-h ruminal in vitro starch digestibility (ivStarchD), and (2) to evaluate the effect of ensiling on pH, ammonia-N, soluble CP, and ivStarchD measurements in HMC. A data set comprising 6,131 HMC samples (55 to 80% DM) obtained from a commercial feed analysis laboratory was used for this study. Month of sample submittal was assumed to be associated with length of the ensiling period. Data for month of sample submittal were analyzed using Proc Mixed in SAS (SAS Institute Inc., Cary, NC) with month as a fixed effect. Regressions to determine linear and quadratic relationships between ivStarchD and ammonia-N, soluble CP, pH, and DM content were performed using Proc Mixed. The ivStarchD increased by 9 percentage units from October to August of the following year. Similar results were observed for ammonia-N and soluble CP with increases from 1.8 to 4.6% of CP and 31.3 to 46.4% of CP, respectively, from October to August of the following year. Ammonia-N was positively related to ivStarchD (R(2)=0.61). The DM content of HMC at silo removal was negatively related (R(2)=0.47) to ivStarchD with a decrease of 1.6 percentage units in ivStarchD per 1-percentage-unit increase in DM content. The pH of HMC was negatively related to ammonia-N (R(2)=0.53), soluble CP (R(2)=0.57), and ivStarchD (R(2)=0.51). Combined, ammonia-N, DM, soluble CP, and pH provided a good prediction of ivStarchD (adjusted R(2)=0.70). Increasing pH, ammonia-N, soluble CP, and ivStarchD values indicate that HMC may need up to 10 mo of ensiling to reach maximum starch digestibility. Ammonia-N, DM content, soluble CP concentration, and pH are good indicators of ruminal in vitro starch digestibility for high-moisture corn. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Functional properties of meat by-products and mechanically separated chicken (MSC) in a high-moisture model petfood system.

PubMed

Rivera, J A; Sebranek, J G; Rust, R E

2000-05-01

Contributions to water retention capacity (% WRC) and texture changes were determined for pork by-products (lung lobes, kidneys), chicken viscera (head, feet and viscera) and mechanically separated chicken (MSC) as affected by pH and various salts in a high-moisture model system. The % WRC for meat by-products and MSC was increased by increased pH (4.5-6.8). Pork lungs and MSC had the highest % WRC (p<0.05) among the meat by-products. Meat by-product % WRC was not signifcantly (p>0.05) affected by salt (2%), phosphate (0.3%) or NaOH (0.075%). Chicken viscera had the lowest (p<0.05) mean texture measurements among the meat by-products and MSC. Strong negative correlations (p<0.05) were obtained for texture with total collagen, soluble collagen and high ionic strength soluble (HIS) proteins. These results should be considered for product quality changes when these by-products are used in formulation of high moisture pet food products.

Solubility of lysozyme in polyethylene glycol-electrolyte mixtures: the depletion interaction and ion-specific effects.

PubMed

Boncina, Matjaz; Rescic, Jurij; Vlachy, Vojko

2008-08-01

The solubility of aqueous solutions of lysozyme in the presence of polyethylene glycol and various alkaline salts was studied experimentally. The protein-electrolyte mixture was titrated with polyethylene glycol, and when precipitation of the protein occurred, a strong increase of the absorbance at 340 nm was observed. The solubility data were obtained as a function of experimental variables such as protein and electrolyte concentrations, electrolyte type, degree of polymerization of polyethylene glycol, and pH of the solution; the last defines the net charge of the lysozyme. The results indicate that the solubility of lysozyme decreases with the addition of polyethylene glycol; the solubility is lower for a polyethylene glycol with a higher degree of polymerization. Further, the logarithm of the protein solubility is a linear function of the polyethylene glycol concentration. The process is reversible and the protein remains in its native form. An increase of the electrolyte (NaCl) concentration decreases the solubility of lysozyme in the presence and absence of polyethylene glycol. The effect can be explained by the screening of the charged amino residues of the protein. The solubility experiments were performed at two different pH values (pH = 4.0 and 6.0), where the lysozyme net charge was +11 and +8, respectively. Ion-specific effects were systematically investigated. Anions such as Br(-), Cl(-), F(-), and H(2)PO(4)(-) (all in combination with Na(+)), when acting as counterions to a protein with positive net charge, exhibit a strong effect on the lysozyme solubility. The differences in protein solubility for chloride solutions with different cations Cs(+), K(+), and Na(+) (coions) were much smaller. The results at pH = 4.0 show that anions decrease the lysozyme solubility in the order F(-) < H(2)PO(4)(-) < Cl(-) < Br(-) (the inverse Hofmeister series), whereas cations follow the direct Hofmeister series (Cs(+) < K(+) < Na(+)) in this situation.

Role of Self-Association and Supersaturation in Oral Absorption of a Poorly Soluble Weakly Basic Drug.

PubMed

Narang, Ajit S; Badawy, Sherif; Ye, Qingmei; Patel, Dhaval; Vincent, Maria; Raghavan, Krishnaswamy; Huang, Yande; Yamniuk, Aaron; Vig, Balvinder; Crison, John; Derbin, George; Xu, Yan; Ramirez, Antonio; Galella, Michael; Rinaldi, Frank A

2015-08-01

Precipitation of weakly basic drugs in intestinal fluids can affect oral drug absorption. In this study, the implications of self-association of brivanib alaninate in acidic aqueous solution, leading to supersaturation at basic pH condition, on its solubility and oral absorption were investigated. Self-association of brivanib alaninate was investigated by proton NMR spectroscopy, surface tension measurement, dynamic light scattering, isothermal titration calorimetry, and molecular modeling. Drug solubility was determined in various pH media, and its tendency to supersaturate upon pH shift was investigated in buffered and biorelevant aqueous solutions. Pharmacokinetic modeling of human oral drug absorption was utilized for parameter sensitivity analyses of input variables. Brivanib alaninate exhibited continuous, and pH- and concentration-dependent self-association. This phenomenon resulted in positive deviation of drug solubility at acidic pH and the formation of a stable supersaturated drug solution in pH-shift assays. Consistent with the supersaturation phenomenon observed in vitro, oral absorption simulations necessitated invoking long precipitation time in the intestine to successfully predict in vivo data. Self-association of a weakly basic drug in acidic aqueous solution can increase its oral absorption by supersaturation and precipitation resistance at the intestinal pH. This consideration is important to the selection of parameters for oral absorption simulation.

Effects of pH and Salts on Physical and Mechanical Properties of Pea Starch Films.

PubMed

Choi, W S; Patel, D; Han, J H

2016-07-01

To identify the significant contribution of intermolecular hydrogen bonds of starch molecules to the film structure formation, pH of film-forming solutions was adjusted and also various salts (NaCl, CaCl2 , CaSO4 , and K2 SO4 ) were mixed into the glycerol-plasticized pea starch film. The film made from pH 7 possessed the highest tensile strength-at-break (2 times) and elastic modulus (4 to 15 times) and the lowest elongation-at-break compared with those of the films made from acid and alkali environments. The pH 7 film also has the highest film density and the lowest total soluble matter. At the level of 0.01 to 0.1 M of CaSO4 and 0.1 M of K2 SO4 in a kilogram of starch, the water solubility of the film increased, while chloride salts slightly lowered the solubility. NaCl and CaSO4 reduced water vapor permeability (WVP), while CaCl2 slightly increased WVP at 0.01 and 0.06 M concentrations, and K2 SO4 significantly increased WVP at 0.03 and 0.15 M. Presence of salts increased tensile strength (5 to 14 times than the control films) and elastic modulus (35 to 180 times) of starch film at 0.01 to 0.03 M of CaSO4 and K2 SO4 . Elongation-at-break increased significantly as salt concentration increases to an optimal level. However, when the concentration exceeded above the optimal level, the E of starch films decreased and showed no significant difference from the control film. Overall, the addition of salts modified physical and mechanical properties of pea starch films more than pH adjustment without any salt addition. © 2016 Institute of Food Technologists®

Floating lipid beads for the improvement of bioavailability of poorly soluble basic drugs: in-vitro optimization and in-vivo performance in humans.

PubMed

Abouelatta, Samar M; Aboelwafa, Ahmed A; Khalil, Rawia M; ElGazayerly, Omaima N

2015-01-01

The challenge in developing oral drug delivery systems of poorly soluble basic drugs is primarily due to their pH dependent solubility. Cinnarizine (CNZ), a model for a poorly soluble basic drug, has pH dependent solubility; where it dissolves readily at low pH in the stomach and exhibits a very low solubility at pH values greater than 4. It is also characterized by a short half life of 3-6h, which requires frequent daily administration resulting in poor patient compliance. In an attempt to solve these problems, extended release floating lipid beads were formulated. A 2(4) full factorial design was utilized for optimization of the effects of various independent variables; lipid:drug ratio, % Pluronic F-127, % Sterotex, and Gelucire 43/01:Gelucire 50/13 ratio, on the loading efficiency and release of CNZ from the lipid beads. In-vivo pharmacokinetic study of the optimized CNZ-lipid beads compared to Stugeron® (reference standard) was performed in healthy human volunteers. A promising approach for enhancing the bioavailability of the poorly soluble basic drug, CNZ, utilizing novel and simple floating lipid beads was successfully developed. Zero order release profile of CNZ was achieved for 12h. Mean AUC0-24 and AUC0-∞ of the optimized CNZ-loaded lipid beads were 4.23 and 6.04 times that of Stugeron® tablets respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

Isolation of a latent polyphenol oxidase from loquat fruit (Eriobotrya japonica Lindl.): kinetic characterization and comparison with the active form.

PubMed

Sellés-Marchart, Susana; Casado-Vela, Juan; Bru-Martínez, Roque

2006-02-15

Polyphenol oxidase (PPO) has been extracted from both soluble and particulate fractions of loquat fruit (Eriobotrya japonica Lindl. cv. Algerie). The soluble PPO (20% of total activity) was partially purified 3.3-fold after ammonium sulfate fractionation being in its active state. The particulate PPO fraction (80% of total activity) was purified to homogeneity in a latent form being activable by sodium dodecyl sulfate (SDS). The enzyme was purified 40.0-fold with a total yield of 15.3% after extraction by phase partitioning in Triton X-114 followed by three chromatographic steps. The molecular weight was estimated to be about 59.2 and 61.2 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography, respectively, indicating that latent PPO is a monomer. Latent PPO catalyzed the oxidation of chlorogenic acid (CA) at a rate 50-fold faster than that of 4-tert-butylcatechol (TBC) but the soluble active counterpart only twice. Both PPOs exhibited similar Km values for TBC but Km for CA was 5-fold higher for the latent than for the active soluble PPO. Other kinetic characteristics, including sensitivity to inhibitors, substrate specificity, thermal stability, temperature, and pH profiles, were quite different between both PPOs. These results provide strong evidences that the soluble active and the particulate latent are different forms of PPO in loquat fruit flesh. The results suggest that the major PPO form for the oxidation of CA, leading to enzymatic browning under physiological conditions, is the latent one.

Condition of copper and organic matter in the soil contaminated with metal remediation of humic substances.

NASA Astrophysics Data System (ADS)

Kolchanova, Kseniia; Barsova, Natalia; Motuzova, Galina; Stepanov, Andrey; Karpukhin, Mikhail

2017-04-01

The aim of this study was to investigate the forms of copper and transformation of organic matter in the soil under the influence of humic substances (potassium humate, which was obtained from coal). The object of research was the top layer of soil model field experience. Field experiments were carried out in 10-liter plastic containers.The upper layers were constructed artificially as mixture of loam, sand and peat. Below it was a layer of loam, then gravel and under it we installed lysimeters. The experiment was conducted in 3 settings: 1) control, 2) control + Cu, and 3) control + Cu + potassium humate . Copper was deposited into upper layer at soil column construction as dry powder (CuSO4*5H2O), which is 1000mg per kg. Humic substance was introduced on surface as liquid form. The focus was the state of the copper and organic matter of solid and liquid phase. In the solid phase pH, carbon content, the molecular-mass distributions for the organic matter, total (HNO3 conc.+ H2O2; decomposition in a microwave oven) and acid-soluble (1H HNO3) copper content, sequential extraction of copper (1 M MgCl2, acetate buffer pH 4,8 (AAB), 1% EDTA) were determined. For liquid phase characteristics aqueous extract was obtained and identified therein: pH, total activity and copper content and water-soluble organic matter(WOM) amphiphilic properties. The introduction of copper is accompanied by a decrease in pH in soils from 7 to 6,3. The introduction of the humic substance softens this effect. Introducing humic preparation gives an increase in carbon at 0.5%. HS and copper has no significant effect on the molecular-mass distribution of solid organic matter. Only about 4% introduced copper accounted for the exchangeable form (MgCl2) for the variant only copper contaminated. Copper, mainly precipitated as hydroxides, moved in an AAB extract. And compared with the exchangeable forms its quantity increases by 10 times. Still more copper goes into an extract of EDTA, about half of the total. That is, the introduction of humic substances increases the amount of copper associated with organic matter in complexes with high stability constants. The total amount of copper of the results of extraction is 88-96% of the all total content. Water-soluble copper contains only 0.5% of the total. But the introduction of humic substances increases the amount of water-soluble copper is 3 times. This is due to the increase in the content of the WOM by 2.5-3 times, both due to the hydrophobic and hydrophilic factions of WOM. And this leads to a sharp reduction in the activity of copper in the liquid phase. Dual effect of introducing humic substances was obtained on the results of the work. On the one hand the introduction of humic substances contributes the immobilization of copper by increasing the fraction associated with organic matter in the solid phase. On the other hand the introduction of humic substances contributes the mobilization of copper in the liquid phase due to the increase of WOM.

pH-Dependent solubility and permeability criteria for provisional biopharmaceutics classification (BCS and BDDCS) in early drug discovery.

PubMed

Varma, Manthena V; Gardner, Iain; Steyn, Stefanus J; Nkansah, Paul; Rotter, Charles J; Whitney-Pickett, Carrie; Zhang, Hui; Di, Li; Cram, Michael; Fenner, Katherine S; El-Kattan, Ayman F

2012-05-07

The Biopharmaceutics Classification System (BCS) is a scientific framework that provides a basis for predicting the oral absorption of drugs. These concepts have been extended in the Biopharmaceutics Drug Disposition Classification System (BDDCS) to explain the potential mechanism of drug clearance and understand the effects of uptake and efflux transporters on absorption, distribution, metabolism, and elimination. The objective of present work is to establish criteria for provisional biopharmaceutics classification using pH-dependent passive permeability and aqueous solubility data generated from high throughput screening methodologies in drug discovery settings. The apparent permeability across monolayers of clonal cell line of Madin-Darby canine kidney cells, selected for low endogenous efflux transporter expression, was measured for a set of 105 drugs, with known BCS and BDDCS class. The permeability at apical pH 6.5 for acidic drugs and at pH 7.4 for nonacidic drugs showed a good correlation with the fraction absorbed in human (Fa). Receiver operating characteristic (ROC) curve analysis was utilized to define the permeability class boundary. At permeability ≥ 5 × 10(-6) cm/s, the accuracy of predicting Fa of ≥ 0.90 was 87%. Also, this cutoff showed more than 80% sensitivity and specificity in predicting the literature permeability classes (BCS), and the metabolism classes (BDDCS). The equilibrium solubility of a subset of 49 drugs was measured in pH 1.2 medium, pH 6.5 phosphate buffer, and in FaSSIF medium (pH 6.5). Although dose was not considered, good concordance of the measured solubility with BCS and BDDCS solubility class was achieved, when solubility at pH 1.2 was used for acidic compounds and FaSSIF solubility was used for basic, neutral, and zwitterionic compounds. Using a cutoff of 200 μg/mL, the data set suggested a 93% sensitivity and 86% specificity in predicting both the BCS and BDDCS solubility classes. In conclusion, this study identified pH-dependent permeability and solubility criteria that can be used to assign provisional biopharmaceutics class at early stage of the drug discovery process. Additionally, such a classification system will enable discovery scientists to assess the potential limiting factors to oral absorption, as well as help predict the drug disposition mechanisms and potential drug-drug interactions.

Foaming and emulsifying properties of porcine red cell protein concentrate.

PubMed

Salvador, P; Saguer, E; Parés, D; Carretero, C; Toldrà, M

2010-08-01

This work focuses on studying the effects of pH (7.0 and 4.5) and protein concentration on the foaming and emulsifying properties of fresh (F) and spray-dried (SD) porcine red cell protein (RCP) concentrates in order to evaluate the proper use of this blood protein as a functional food ingredient. Also, protein solubility is measured through the pH range from 3.0 to 8.0. In each case, all concentrates show a high solubility, although this is significantly affected by pH. Spray drying slightly reduces the solubility at mild acid and neutral conditions. The foaming capacity is found to be dependent on pH as well as on the drying treatment. SD-RCP concentrates show better foaming capacity than F-RCP. The minimum protein concentration required to attain the highest foaming capacity is found under acid pH for the spray-dried concentrates. Although F-RCP shows low foam stability at acid and neutral pH, spray drying and protein content enhance the stability of foams. Emulsifying properties show dependence on pH as well as on protein content. Furthermore, spray drying affects the emulsifying properties but in different ways, depending on pH and protein concentration.

Multivariate analysis of sludge disintegration by microwave-hydrogen peroxide pretreatment process.

PubMed

Ya-Wei, Wang; Cheng-Min, Gui; Xiao-Tang, Ni; Mei-Xue, Chen; Yuan-Song, Wei

2015-01-01

Microwave irradiation (with H2O2) has been shown to offer considerable advantages owing to its flexible control, low overall cost, and resulting higher soluble chemical oxygen demand (SCOD); accordingly, the method has been proposed recently as a means of improving sludge disintegration. However, the key factor controlling this sludge pretreatment process, pH, has received insufficient attention to date. To address this, the response surface approach (central composite design) was applied to evaluate the effects of total suspended solids (TSS, 2-20 g/L), pH (4-10), and H2O2 dosage (0-2 w/w) and their interactions on 16 response variables (e.g., SCODreleased, pH, H2O2remaining). The results demonstrated that all three factors affect sludge disintegration significantly, and no pronounced interactions between response variables were observed during disintegration, except for three variables (TCOD, TSSremaining, and H2O2 remaining). Quadratic predictive models were constructed for all 16 response variables (R(2): 0.871-0.991). Taking soluble chemical oxygen demand (SCOD) as an example, the model and coefficients derived above were able to predict the performance of microwave pretreatment (enhanced by H2O2 and pH adjustment) from previously published studies. The predictive models developed were able to optimize the treatment process for multiple disintegration objectives. Copyright © 2014 Elsevier B.V. All rights reserved.

Functional properties of protein from frozen mantle and fin of jumbo squid Dosidicus gigas in function of pH and ionic strength.

PubMed

Rocha-Estrada, J G; Córdova-Murueta, J H; García-Carreño, F L

2010-10-01

Functional properties of protein from mantle and fin of the jumbo squid Dosidicus gigas were explained based on microscopic muscle fiber and protein fractions profiles as observed in SDS-PAGE. Fin has higher content of connective tissue and complex fiber arrangement, and we observed higher hardness of fin gels as expected. Myosin heavy chain (MHC) was found in sarcoplasmic, myofibril and soluble-in-alkali fractions of mantle and only in sarcoplasmic and soluble-in-alkali fractions of fin. An additive effect of salt concentration and pH affected the solubility and foaming properties. Fin and mantle proteins yielded similar results in solubility tests, but significant differences occurred for specific pH and concentrations of salt. Foaming capacity was proportional to solubility; foam stability was also affected by pH and salt concentration. Hardness and fracture strength of fin gels were significantly higher than mantle gels; gels from proteins of both tissues reached the highest level in the folding test. Structural and molecular properties, such as MHC and paramyosin solubility, arrangement of muscle fibers and the content of connective tissue were useful to explain the differences observed in these protein properties. High-strength gels can be formed from squid mantle or fin muscle. Fin displayed similar or better properties than mantle in all tests.

A water-soluble rhodamine B-derived fluorescent probe for pH monitoring and imaging in acidic regions

NASA Astrophysics Data System (ADS)

Cui, Peng; Jiang, Xuekai; Sun, Junyong; Zhang, Qiang; Gao, Feng

2017-06-01

A structurally simple, water-soluble rhodamine-derivatived fluorescent probe, which is responsive to acidic pH, was conveniently synthesized via a one-step condensation reaction of rhodamine B hydrazide and 4-formybenzene-1,3-disulfonate. As a stable and highly sensitive pH sensor, the probe displays an approximately 50-fold fluorescence enhancement over the pH range of 7.16-4.89 as the structure of probe changes from spirocyclic (weak fluorescent) to ring-open (strong fluorescent) with decreasing pH. The synthesized fluorescent probe is applied to the detection of pH changes in vitro and in vivo bioimaging of immortalized gastric cancer cells, with satisfactory results.

Rapid and Accurate Evaluation of the Quality of Commercial Organic Fertilizers Using Near Infrared Spectroscopy

PubMed Central

Wang, Chang; Huang, Chichao; Qian, Jian; Xiao, Jian; Li, Huan; Wen, Yongli; He, Xinhua; Ran, Wei; Shen, Qirong; Yu, Guanghui

2014-01-01

The composting industry has been growing rapidly in China because of a boom in the animal industry. Therefore, a rapid and accurate assessment of the quality of commercial organic fertilizers is of the utmost importance. In this study, a novel technique that combines near infrared (NIR) spectroscopy with partial least squares (PLS) analysis is developed for rapidly and accurately assessing commercial organic fertilizers quality. A total of 104 commercial organic fertilizers were collected from full-scale compost factories in Jiangsu Province, east China. In general, the NIR-PLS technique showed accurate predictions of the total organic matter, water soluble organic nitrogen, pH, and germination index; less accurate results of the moisture, total nitrogen, and electrical conductivity; and the least accurate results for water soluble organic carbon. Our results suggested the combined NIR-PLS technique could be applied as a valuable tool to rapidly and accurately assess the quality of commercial organic fertilizers. PMID:24586313

Rapid and accurate evaluation of the quality of commercial organic fertilizers using near infrared spectroscopy.

PubMed

Wang, Chang; Huang, Chichao; Qian, Jian; Xiao, Jian; Li, Huan; Wen, Yongli; He, Xinhua; Ran, Wei; Shen, Qirong; Yu, Guanghui

2014-01-01

The composting industry has been growing rapidly in China because of a boom in the animal industry. Therefore, a rapid and accurate assessment of the quality of commercial organic fertilizers is of the utmost importance. In this study, a novel technique that combines near infrared (NIR) spectroscopy with partial least squares (PLS) analysis is developed for rapidly and accurately assessing commercial organic fertilizers quality. A total of 104 commercial organic fertilizers were collected from full-scale compost factories in Jiangsu Province, east China. In general, the NIR-PLS technique showed accurate predictions of the total organic matter, water soluble organic nitrogen, pH, and germination index; less accurate results of the moisture, total nitrogen, and electrical conductivity; and the least accurate results for water soluble organic carbon. Our results suggested the combined NIR-PLS technique could be applied as a valuable tool to rapidly and accurately assess the quality of commercial organic fertilizers.

Antioxidant and α-glucosidase inhibitory activities of 40 tropical juices from Malaysia and identification of phenolics from the bioactive fruit juices of Barringtonia racemosa and Phyllanthus acidus.

PubMed

Sulaiman, Shaida Fariza; Ooi, Kheng Leong

2014-10-01

The present study compared pH, total soluble solids, vitamin C, and total phenolic contents, antioxidant activities, and α-glucosidase inhibitory activities of 40 fresh juices. The juice of Baccaurea polyneura showed the highest yield (74.17 ± 1.44%) and total soluble solids (32.83 ± 0.27 °Brix). The highest and lowest pH values were respectively measured from the juices of Dimocarpus longan (6.87 ± 0.01) and Averrhoa bilimbi (1.67 ± 0.67). The juice of Psidium guajava gave the highest total phenolic (857.24 ± 12.65 μg GAE/g sample) and vitamin C contents (590.31 ± 7.44 μg AAE/g sample). The juice of Phyllanthus acidus with moderate contents of total phenolics and vitamin C was found to exhibit the greatest scavenging (613.71 ± 2.59 μg VCEAC/g sample), reducing (2784.89 ± 3.93 μg TEAC/g sample), and α-glucosidase inhibitory activities (95.37 ± 0.15%). The juice of Barringtonia racemosa was ranked second in the activities and total phenolic content. Gallic and ellagic acids, which were quantified as the major phenolics of the respective juices, are suggested to be the main contributors to the antioxidant activities. The α-glucosidase inhibitory activity of the juices could be derived from myricetin and quercetin (that were previously reported as potent α-glucosidase inhibitors) in the hydrolyzed juice extracts. The juice of Syzygium samarangense, which was found to be highest in metal chelating activity (82.28 ± 0.10%), also was found to have these phenolics.

Environmentally safe sewage sludge disposal: the impact of liming on the behaviour of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn.

PubMed

Scancar, J; Milacic, R; Strazar, M; Burica, O; Bukovec, P

2001-02-01

Dewatered sewage sludge containing relatively high total concentrations of Cr (945 micrograms ml-1), Cu (523 micrograms ml-1), Ni (1186 micrograms ml-1) and Zn (2950 micrograms ml-1) was treated with quicklime and sawdust for sludge disinfection and post-stabilisation. The mobility of the heavy metals in the sludge samples was assessed by applying a modified five-step Tessier sequential extraction procedure. Water was added as a first step for estimation of the proportion of the easily soluble metal fractions. To check the precision of the analytical work the concentrations of heavy metals in steps 1-6 of the extraction procedure were summed and compared to the total metal concentrations. The mass balance agreed within +/- 3% for Cd, Cu, Cr, and Zn and within +/- 5% for Ni, Pb, Fe and Mn. Data from the partitioning study indicate that in the lime-treated sludge at a pH of 12 the mobility of Cu and Ni notably increased with the solubilisation of these metals from their organic and/or carbonate and Fe and Mn oxide and hydroxide fractions, respectively. Liming slightly decreased the proportion of other heavy metals in the easily soluble fractions while its impact on the partitioning between other sludge phases was almost insignificant. Due to the increased solubility of Ni and Cu as well as potential Cr oxidation at high pH, liming cannot be recommended for sludge disinfection. Addition of sawdust did not change the heavy metal partitioning.

Proximate composition of Karkadeh (Hibiscus sabdariffa) seeds and some functional properties of seed protein isolate as influenced by pH and NaCl.

PubMed

Salah, E O Mahgoub; Hayat, Z E Elbashir

2009-05-01

Seeds of an inbred line (B-11-90) of Karkadeh (Hibiscus sabdariffa) were investigated for their proximate composition (AOAC methods), nitrogen solubility and protein isolate (Karkadeh seed protein isolates [KSPI]) functional properties (standard methods). The fat and protein contents of the seeds were 22.43% and 32.46%, respectively. Nitrogen solubility was good in both water and 1.0 M NaCl at alkaline pH rather than at acidic pH, with better solubility at higher pH levels in water than in 1.0 M NaCl. The functional properties of the KSPI were as follows: water absorption capacity, 181 ml/100 g; fat absorption capacity, 110 ml/100 g; bulk density, 0.77 g/ml; and apparent viscosity (at 20 degrees C), 13.42 cps. KSPI showed a maximum foaming capacity at pH 12 and 1.6 M NaCl, a maximum emulsification capacity at pH 11 and 1.8 M NaCl, and a weaker foam stability at neutral pH than at acidic or alkaline pH, with a better foam stability at alkaline pH. The foam stability was considerably improved by treatment with 1.6 M NaCl.

Effect of formulation and processing variables on the characteristics of microspheres for water-soluble drugs prepared by w/o/o double emulsion solvent diffusion method.

PubMed

Lee, J; Park, T G; Choi, H

2000-02-25

80% except for acetaminophen, due to its lower solubility in water and higher solubility in corn oil. The release profile of the drug was pH dependent. In acidic medium, the release rate was much slower, however, the drug was released quickly at pH 7.4. Tacrine showed unexpected release profiles, probably due to ionic interaction with polymer matrix and the shell structure and the highest release rate was obtained at pH 2.0. The prepared microspheres had a sponge-like inner structure with or without central hollow core and the surface was dense with no apparent pores.

Theoretical Analysis of Drug Dissolution: I. Solubility and Intrinsic Dissolution Rate.

PubMed

Shekunov, Boris; Montgomery, Eda Ross

2016-09-01

The first-principles approach presented in this work combines surface kinetics and convective diffusion modeling applied to compounds with pH-dependent solubility and in different dissolution media. This analysis is based on experimental data available for approximately 100 compounds of pharmaceutical interest. Overall, there is a linear relationship between the drug solubility and intrinsic dissolution rate expressed through the total kinetic coefficient of dissolution and dimensionless numbers defining the mass transfer regime. The contribution of surface kinetics appears to be significant constituting on average ∼20% resistance to the dissolution flux in the compendial rotating disk apparatus at 100 rpm. The surface kinetics contribution becomes more dominant under conditions of fast laminar or turbulent flows or in cases when the surface kinetic coefficient may decrease as a function of solution composition or pH. Limitations of the well-known convective diffusion equation for rotating disk by Levich are examined using direct computational modeling with simultaneous dissociation and acid-base reactions in which intrinsic dissolution rate is strongly dependent on pH profile and solution ionic strength. It is shown that concept of diffusion boundary layer does not strictly apply for reacting/interacting species and that thin-film diffusion models cannot be used quantitatively in general case. Copyright © 2016. Published by Elsevier Inc.

Thermo-tolerant phosphate-solubilizing microbes for multi-functional biofertilizer preparation.

PubMed

Chang, Cheng-Hsiung; Yang, Shang-Shyng

2009-02-01

In order to prepare the multi-functional biofertilizer, thermo-tolerant phosphate-solubilizing microbes including bacteria, actinomycetes, and fungi were isolated from different compost plants and biofertilizers. Except Streptomycesthermophilus J57 which lacked pectinase, all isolates possessed amylase, CMCase, chitinase, pectinase, protease, lipase, and nitrogenase activities. All isolates could solubilize calcium phosphate and Israel rock phosphate; various isolates could solubilize aluminum phosphate, iron phosphate, and hydroxyapatite. During composting, biofertilizers inoculated with the tested microbes had a significantly higher temperature, ash content, pH, total nitrogen, soluble phosphorus content, and germination rate than non-inoculated biofertilizer; total organic carbon and carbon-to-nitrogen ratio showed the opposite pattern. Adding these microbes can shorten the period of maturity, improve the quality, increase the soluble phosphorus content, and enhance the populations of phosphate-solubilizing and proteolytic microbes in biofertilizers. Therefore, inoculating thermo-tolerant phosphate-solubilizing microbes into agricultural and animal wastes represents a practical strategy for preparing multi-functional biofertilizer.

Influence of gamma radiation on the physicochemical and rheological properties of sterculia gum polysaccharides

NASA Astrophysics Data System (ADS)

Singh, Baljit; Sharma, Vikrant

2013-11-01

Keeping in view the influence of gamma radiation on the physiochemical properties of the polysaccharides and their importance in the food and pharmaceutical industry, in the present study attempt has been made to investigate the effects of absorbed dose on FTIR, XRD, SEMs, absorbance, pH, solubility, water absorption capacity, emulsion stability and rheology of sterculia gum. Increase in solubility and decrease in swellability of gum has been observed on increasing the absorbed dose. The emulsion stability has improved for the gum sample irradiated with total dose of 8.1±0.2 kGy. Apparent viscosity of gum solution first increased with increase in dose from 0 to 8.1±0.2 kGy than decreased with regular trends with further increase in total absorbed dose. Flow behavior of gum solution shifted to Newtonian from non-Newtonian with increasing the dose.

Acid transformation of bauxite residue: Conversion of its alkaline characteristics.

PubMed

Kong, Xiangfeng; Li, Meng; Xue, Shengguo; Hartley, William; Chen, Chengrong; Wu, Chuan; Li, Xiaofei; Li, Yiwei

2017-02-15

Bauxite residue (BR) is a highly alkaline solid hazardous waste produced from bauxite processing for alumina production. Alkaline transformation appears to reduce the environmental risk of bauxite residue disposal areas (BRDAs) whilst potentially providing opportunities for the sustainable reuse and on-going management of BR. Mineral acids, a novel citric acid and a hybrid combination of acid-gypsum treatments were investigated for their potential to reduce residue pH and total alkalinity and transform the alkaline mineral phase. XRD results revealed that with the exception of andradite, the primary alkaline solid phases of cancrinite, grossular and calcite were transformed into discriminative products based on the transformation used. Supernatants separated from BR and transformed bauxite residue (TBR) displayed distinct changes in soluble Na, Ca and Al, and a reduction in pH and total alkalinity. SEM images suggest that mineral acid transformations promote macro-aggregate formation, and the positive promotion of citric acid, confirming the removal or reduction in soluble and exchangeable Na. NEXAFS analysis of Na K-edge revealed that the chemical speciation of Na in TBRs was consistent with BR. Three acid treatments and gypsum combination had no effect on Na speciation, which affects the distribution of Na revealed by sodium STXM imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of binding pH and protein solubility on the dynamic binding capacity in hydrophobic interaction chromatography.

PubMed

Baumann, Pascal; Baumgartner, Kai; Hubbuch, Jürgen

2015-05-29

Hydrophobic interaction chromatography (HIC) is one of the most frequently used purification methods in biopharmaceutical industry. A major drawback of HIC, however, is the rather low dynamic binding capacity (DBC) obtained when compared to e.g. ion exchange chromatography (IEX). The typical purification procedure for HIC includes binding at neutral pH, independently of the proteins nature and isoelectric point. Most approaches to process intensification are based on resin and salt screenings. In this paper a combination of protein solubility data and varying binding pH leads to a clear enhancement of dynamic binding capacity. This is shown for three proteins of acidic, neutral, and alkaline isoelectric points. High-throughput solubility screenings as well as miniaturized and parallelized breakthrough curves on Media Scout RoboColumns (Atoll, Germany) were conducted at pH 3-10 on a fully automated robotic workstation. The screening results show a correlation between the DBC and the operational pH, the protein's isoelectric point and the overall solubility. Also, an inverse relationship of DBC in HIC and the binding kinetics was observed. By changing the operational pH, the DBC could be increased up to 30% compared to the standard purification procedure performed at neutral pH. As structural changes of the protein are reported during HIC processes, the applied samples and the elution fractions were proven not to be irreversibly unfolded. Copyright © 2015 Elsevier B.V. All rights reserved.

The influence of pH on the leaching behaviour of inorganic components from municipal solid waste APC residues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quina, Margarida J.; Bordado, Joao C.M.; Quinta-Ferreira, Rosa M.

2009-09-15

The influence of pH on the leaching behaviour of air pollution control (APC) residues produced in municipal solid waste incineration (MSWI) is addressed in this study. The residue is considered hazardous waste, and in accordance with their chemical properties, the leaching of contaminants into the environment is the main concern. Several leaching tests can be used for research studies or regulatory purposes, where a wide variety of conditions may be tested. Our work deals mainly with the leaching behaviour of toxic heavy metals (Pb, Cd, Zn, Cr, Ni, Cu) and inorganics associated with soluble salts (Na, K, Ca, Cl). Themore » main goal is to obtain an overview of the leachability of APC residues produced in a Portuguese MSWI process. Among the different variables that may have influence on the leaching behaviour, pH of the leachant solution is the most important one, and was evaluated through pH static tests. The acid neutralization capacity (ANC) of the residue was also determined, which is in the range of 6.2-6.8 meq g{sup -1} (for pH = 7) and 10.1-11.6 meq g{sup -1} (for pH = 4). The analysis of the leaching behaviour is particularly important when the leaching is solubility controlled. The amphoteric behaviour of some elements was observed, namely for Pb and Zn, which is characterized through high solubilization at low and high pH and moderate or low solubility at neutral or moderate high pH. The solubility curves for Pb, Cd, Zn, Cr, Ni and Cu as a function of pH were obtained, which are very useful for predicting the leaching behaviour in different scenarios. The solubility of K and Na reveals to be nearly independent of the solution pH and the released amount is mainly availability-controlled. Moreover, the pH static test showed that Cl{sup -} is the most pH-independent species. The APC residue turns out to be a hazardous waste because of the high leaching of lead and chloride. On the other hand, leaching of elements like cadmium, nickel and copper is limited by the high pH of the residue, and as long as the waste keeps its ANC, the risk of mobilization of these elements is low.« less

Effect of rhamnolipid biosurfactant on solubilization of polycyclic aromatic hydrocarbons.

PubMed

Li, Shudong; Pi, Yongrui; Bao, Mutai; Zhang, Cong; Zhao, Dongwei; Li, Yiming; Sun, Peiyan; Lu, Jinren

2015-12-15

Rhamnolipid biosurfactant-producing bacteria, Bacillus Lz-2, was isolated from oil polluted water collected from Dongying Shengli oilfield, China. The factors that influence PAH solubilization such as biosurfactant concentration, pH, ionic strength and temperature were discussed. The results showed that the solubilities of naphthalene, phenanthrene and pyrene increased linearly with the rise of rhamnolipid biosurfactant dose above the biosurfactant critical micelle concentration (CMC). Furthermore, the molar solubilization ratio (MSR) values decreased in the following order: naphthalene>phenanthrene>pyrene. However, the solubility percentage increased and followed the opposite order: pyrene>phenanthrene>naphthalene. The solubilities of PAHs in rhamnolipid biosurfactant solution increased with the rise of pH and ionic strength, and reached the maximum values under the conditions of pH11 and NaCl concentration 8 g · L(-1). The solubility of phenanthrene and pyrene increased with the rise of temperature. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of hydrotalcite-like compounds on the aqueous solubility of some poorly water-soluble drugs.

PubMed

Ambrogi, Valeria; Fardella, Giuseppe; Grandolini, Giuliano; Nocchetti, Morena; Perioli, Luana

2003-07-01

A new approach of improving drug dissolution properties is described. This method exploits the property of a carrier owing to the hydrotalcite-type anionic clays (HTlc). HTlc is an inorganic layered solid that lodges anionic compounds among its layers. As HTlc dissolves at acidic pH values (pH < 4), the anions intercalated among the layers are promptly released in the medium. In this article some nonsteroidal antiinflammatory drugs were chosen as models of poorly water-soluble drugs. They were intercalated in HTlc and solubility measurements in acidic medium were performed. A remarkable improvement of drug solubility was observed especially in the case of indomethacin. Copyright 2003 Wiley-Liss, Inc. and the American Pharmacists Association

Measured solubilities and speciations of neptunium, plutonium, and americium in a typical groundwater (J-13) from the Yucca Mountain region; Milestone report 3010-WBS 1.2.3.4.1.3.1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nitsche, H.; Gatti, R.C.; Standifer, E.M.

1993-07-01

Solubility and speciation data are important in understanding aqueous radionuclide transport through the geosphere. They define the source term for transport retardation processes such as sorption and colloid formation. Solubility and speciation data are useful in verifying the validity of geochemical codes that are part of predictive transport models. Results are presented from solubility and speciation experiments of {sup 237}NpO{sub 2}{sup +}, {sup 239}Pu{sup 4+}, {sup 241}Am{sup 3+}/Nd{sup 3+}, and {sup 243}Am{sup 3+} in J-13 groundwater (from the Yucca Mountain region, Nevada, which is being investigated as a potential high-level nuclear waste disposal site) at three different temperatures (25{degree}, 60{degree},more » and 90{degree}C) and pH values (5.9, 7.0, and 8.5). The solubility-controlling steady-state solids were identified and the speciation and/or oxidation states present in the supernatant solutions were determined. The neptunium solubility decreased with increasing temperature and pH. Plutonium concentrations decreased with increasing temperature and showed no trend with pH. The americium solutions showed no clear solubility trend with increasing temperature and increasing pH.« less

Effects of copper source and concentration on in vitro phytate phosphorus hydrolysis by phytase.

PubMed

Pang, Yanfang; Applegate, Todd J

2006-03-08

Five copper (Cu) sources were studied at pH 2.5, 5.5, and 6.5 to determine how Cu affects phytate phosphorus (PP) hydrolysis by phytase at concentrations up to 500 mg/kg diet (60 min, 40-41 degrees C). Subsequently, Cu solubility with and without sodium phytate was measured. Adding Cu inhibited PP hydrolysis at pH 5.5 and pH 6.5 (P < 0.05). This inhibition was greater with higher concentrations of Cu. Tri-basic copper chloride and copper lysinate inhibited PP hydrolysis much less than copper sulfate pentahydrate, copper chloride, and copper citrate (P < 0.05). A strong negative relationship was observed between PP hydrolysis and soluble Cu at pH 5.5 (r = -0.76, P < 0.0001) and 6.5 (r = -0.54, P < 0.0001). In conclusion, pH, Cu concentration, and source influenced PP hydrolysis by phytase in vitro and were related to the amount of soluble Cu and the formation of insoluble copper-phytin complexes.

Oral Sustained Release of a Hydrophilic Drug Using the Lauryl Sulfate Salt/Complex.

PubMed

Kasashima, Yuuki; Yoshihara, Keiichi; Yasuji, Takehiko; Sako, Kazuhiro; Uchida, Shinya; Namiki, Noriyuki

2016-01-01

The objective of this study was to establish the key factor of the lauryl sulfate (LS) salt/complex for sustained release of a hydrophilic drug at various physiological pH levels. Mirabegron is a hydrophilic drug that exhibits pH-dependent solubility. Sodium lauryl sulfate (SLS) bound to mirabegron in a stoichiometric manner. The formation of the LS salt/complex significantly reduced mirabegron solubility and helped achieve sustained release of mirabegron over a wide range of pH levels. In addition to SLS, other additives containing a sulfate group formed salts/complexes with mirabegron and reduced its solubility at different pH levels. Furthermore, octyl sulfate (OS), myristyl sulfate (MS), and cetyl sulfate (CS) salts/complexes, which contain alkyl chains of different lengths, showed a lower solubility than mirabegron and promoted sustained release of mirabegron. The rank order of solubility and dissolution rate were as follows: OS salt/complex>LS salt/complex>MS salt/complex>CS salt/complex, which corresponded to the rank of alkyl chain lengths. We conclude that the presence of a sulfate group and the length of the alkyl chain are key factors of the LS salt/complex for sustained release of a hydrophilic drug at various physiological pH levels.

The effects of electrical stunning voltage on meat quality, plasma parameters, and protein solubility of broiler breast meat.

PubMed

Huang, J C; Yang, J; Huang, M; Chen, K J; Xu, X L; Zhou, G H

2017-03-01

This study was designed to compare the effects of different stunning voltages of pulsed direct current on meat quality of broilers. For this purpose, plasma parameters, blood loss, carcass damage, and meat water holding capacity, color, shear force, pH, and protein solubility were analyzed. A total of 400 broilers were divided into 5 treatment groups and stunned with 5, 15, 25, 35, and 45 V at 750 Hz and 10 s, respectively. Blood samples were collected immediately after cutting the neck. Pectoralis major muscles were removed from the carcass after chilling and placed on ice. Breast muscle pH and meat color were determined at both 2 and 24 h postmortem. Dripping loss, cooking loss, pressing loss, and cooked breast meat shear values were determined after 24 h postmortem. The 5 V treatment significantly increased (P < 0.05) blood plasma corticosterone and lactate concentration compared with the other groups. The carcass damage of wings, Pectoralis major, and Pectoralis minor was significant in the 5, 35, and 45 V groups. The pH of 2 h postmortem in the 5 and 45 V groups was significantly lower (P < 0.05) than in the 15 and 25 V groups. In the 5 and 45 V groups, the protein solubility and shear force value were significantly lower (P < 0.05) and dripping loss was significantly higher (P < 0.05) than the other groups. © 2016 Poultry Science Association Inc.

Preparation of Essential Oil-Based Microemulsions for Improving the Solubility, pH Stability, Photostability, and Skin Permeation of Quercetin.

PubMed

Lv, Xia; Liu, Tiantian; Ma, Huipeng; Tian, Yan; Li, Lei; Li, Zhen; Gao, Meng; Zhang, Jianbin; Tang, Zeyao

2017-11-01

Quercetin can bring many benefits to skin based on its various bioactivities. However, the therapeutic effect of quercetin is limited due to the poor water solubility, pH instability, light instability, and skin permeation. The aim of the present work was applying essential oil-based microemulsions to improve the solubility, pH stability, photostability, and skin permeation of quercetin for topical application. Peppermint oil (PO-ME), clove oil (CO-ME), and rosemary oil (RMO-ME) were selected as model essential oils. Microemulsions composed of Cremophor EL/1,2-propanediol/essential oils (47:23:30, w/w) were selected as model formulations, based on the pseudo-ternary phase diagram and the characterizations. In the solubility study, the solubility of quercetin was improved dozens of times by microemulsions. Quercetin was found instable under alkaline condition, with 50% degraded in the solution of pH 13. However, PO-ME, CO-ME, and RMO-ME could protect quercetin from the hydroxide ions, with 47, 9, and 12% of quercetin degraded. In the photostability study, the essential oil-based microemulsions showed the capability of protecting quercetin from degradation under UV radiation. Where more than 67% of quercetin was degraded in aqueous solution, while less than 7% of quercetin degraded in microemulsions. At last, the in vitro skin permeation study showed that the essential oil-based microemulsions could enhance the permeation capacity of quercetin by 2.5-3 times compared to the aqueous solution. Hence, the prepared essential oil microemulsions could improve the solubility, pH stability, photostability, and skin permeation of quercetin, which will be beneficial for its topical application.

Thermodynamic description of Tc(iv) solubility and carbonate complexation in alkaline NaHCO3-Na2CO3-NaCl systems.

PubMed

Baumann, A; Yalçıntaş, E; Gaona, X; Polly, R; Dardenne, K; Prüßmann, T; Rothe, J; Altmaier, M; Geckeis, H

2018-03-28

The solubility of 99 Tc(iv) was investigated in dilute to concentrated carbonate solutions (0.01 M ≤ C tot ≤ 1.0 M, with C tot = [HCO 3 - ] + [CO 3 2- ]) under systematic variation of ionic strength (I = 0.3-5.0 M NaHCO 3 -Na 2 CO 3 -NaCl-NaOH) and pH m (-log[H + ] = 8.5-14.5). Strongly reducing conditions (pe + pH m ≈ 2) were set with Sn(ii). Carbonate enhances the solubility of Tc(iv) in alkaline conditions by up to 3.5 log 10 -units compared to carbonate-free systems. Solvent extraction and XANES confirmed that Tc was kept as +IV during the timeframe of the experiments (≤ 650 days). Solid phase characterization performed by XAFS, XRD, SEM-EDS, chemical analysis and TG-DTA confirmed that TcO 2 ·0.6H 2 O(am) controls the solubility of Tc(iv) under the conditions investigated. Slope analysis of the solubility data in combination with solid/aqueous phase characterization and DFT calculations indicate the predominance of the species Tc(OH) 3 CO 3 - at pH m ≤ 11 and C tot ≥ 0.01 M, for which thermodynamic and activity models are derived. Solubility data obtained above pH m ≈ 11 indicates the formation of previously unreported Tc(iv)-carbonate species, possibly Tc(OH) 4 CO 3 2- , although the likely formation of additional complexes prevents deriving a thermodynamic model valid for this pH m -region. This work provides the most comprehensive thermodynamic dataset available for the system Tc 4+ -Na + -Cl - -OH - -HCO 3 - -CO 3 2- -H 2 O(l) valid under a range of conditions relevant for nuclear waste disposal.

Differential sensitivity of oleosins to proteolysis during oil body mobilization in sunflower seedlings.

PubMed

Sadeghipour, Hamid Reza; Bhatla, Satish Chander

2002-10-01

Until now, there has been no conclusive demonstration of any in vivo oleosin degradation at the early stages of oil body mobilization. The present work on sunflower (Helianthus annuus L.) has demonstrated limited oleosin degradation during seed germination. Seedling cotyledon homogenization in Tris-urea buffer, followed by SDS-PAGE, revealed three oleosins (16, 17.5 and 20 kDa). Incubation of oil bodies with total soluble protein from 4-day-old seedlings resulted in oleosin degradation. In vitro and in vivo degradation of the 17.5-kDa oleosin was faster than the other two, indicating its greater susceptibility to proteolysis. Oleosin degradation by the total soluble protein resulted in a transient 14.5-kDa polypeptide, followed by an 11-kDa protease-protected fragment, which appeared post-germinatively and accumulated corresponding to increased rate of lipid mobilization. A 65-kDa protease, active at pH 7.5-9.5, was zymographically detected in the total soluble protein. Its activity increased along with in vivo accumulation of the protease-protected fragment during seed germination and accompanying lipid mobilization. Protease-treated oil bodies were more susceptible to maize lipase action. Differential proteolytic sensitivity of different oleosins in the oil body membranes could be a determinant of oil body longevity during seed germination.

Elevated temperature altered photosynthetic products in wheat seedlings and organic compounds and biological activity in rhizopshere soil under cadmium stress.

PubMed

Jia, Xia; Zhao, YongHua; Wang, WenKe; He, Yunhua

2015-09-23

The objective of this study was to investigate the effects of slightly elevated atmospheric temperature in the spring on photosynthetic products in wheat seedlings and on organic compounds and biological activity in rhizosphere soil under cadmium (Cd) stress. Elevated temperature was associated with increased soluble sugars, reducing sugars, starch, and total sugars, and with decreased amino acids in wheat seedlings under Cd stress. Elevated temperature improved total soluble sugars, free amino acids, soluble phenolic acids, and organic acids in rhizosphere soil under Cd stress. The activity of amylase, phenol oxidase, invertase, β-glucosidase, and l-asparaginase in rhizosphere soil was significantly improved by elevated temperature under Cd stress; while cellulase, neutral phosphatase, and urease activity significantly decreased. Elevated temperature significantly improved bacteria, fungi, actinomycetes, and total microorganisms abundance and fluorescein diacetate activity under Cd stress. In conclusion, slightly elevated atmospheric temperature in the spring improved the carbohydrate levels in wheat seedlings and organic compounds and biological activity in rhizosphere soil under Cd stress in the short term. In addition, elevated atmospheric temperature in the spring stimulated available Cd by affecting pH, DOC, phenolic acids, and organic acids in rhizosphere soil, which resulted in the improvement of the Cd uptake by wheat seedlings.

Elevated temperature altered photosynthetic products in wheat seedlings and organic compounds and biological activity in rhizopshere soil under cadmium stress

PubMed Central

Jia, Xia; Zhao, YongHua; Wang, WenKe; He, Yunhua

2015-01-01

The objective of this study was to investigate the effects of slightly elevated atmospheric temperature in the spring on photosynthetic products in wheat seedlings and on organic compounds and biological activity in rhizosphere soil under cadmium (Cd) stress. Elevated temperature was associated with increased soluble sugars, reducing sugars, starch, and total sugars, and with decreased amino acids in wheat seedlings under Cd stress. Elevated temperature improved total soluble sugars, free amino acids, soluble phenolic acids, and organic acids in rhizosphere soil under Cd stress. The activity of amylase, phenol oxidase, invertase, β-glucosidase, and l-asparaginase in rhizosphere soil was significantly improved by elevated temperature under Cd stress; while cellulase, neutral phosphatase, and urease activity significantly decreased. Elevated temperature significantly improved bacteria, fungi, actinomycetes, and total microorganisms abundance and fluorescein diacetate activity under Cd stress. In conclusion, slightly elevated atmospheric temperature in the spring improved the carbohydrate levels in wheat seedlings and organic compounds and biological activity in rhizosphere soil under Cd stress in the short term. In addition, elevated atmospheric temperature in the spring stimulated available Cd by affecting pH, DOC, phenolic acids, and organic acids in rhizosphere soil, which resulted in the improvement of the Cd uptake by wheat seedlings. PMID:26395070

Elevated temperature altered photosynthetic products in wheat seedlings and organic compounds and biological activity in rhizopshere soil under cadmium stress

NASA Astrophysics Data System (ADS)

Jia, Xia; Zhao, Yonghua; Wang, Wenke; He, Yunhua

2015-09-01

The objective of this study was to investigate the effects of slightly elevated atmospheric temperature in the spring on photosynthetic products in wheat seedlings and on organic compounds and biological activity in rhizosphere soil under cadmium (Cd) stress. Elevated temperature was associated with increased soluble sugars, reducing sugars, starch, and total sugars, and with decreased amino acids in wheat seedlings under Cd stress. Elevated temperature improved total soluble sugars, free amino acids, soluble phenolic acids, and organic acids in rhizosphere soil under Cd stress. The activity of amylase, phenol oxidase, invertase, β-glucosidase, and L-asparaginase in rhizosphere soil was significantly improved by elevated temperature under Cd stress; while cellulase, neutral phosphatase, and urease activity significantly decreased. Elevated temperature significantly improved bacteria, fungi, actinomycetes, and total microorganisms abundance and fluorescein diacetate activity under Cd stress. In conclusion, slightly elevated atmospheric temperature in the spring improved the carbohydrate levels in wheat seedlings and organic compounds and biological activity in rhizosphere soil under Cd stress in the short term. In addition, elevated atmospheric temperature in the spring stimulated available Cd by affecting pH, DOC, phenolic acids, and organic acids in rhizosphere soil, which resulted in the improvement of the Cd uptake by wheat seedlings.

Microenvironmental pH-modification to improve dissolution behavior and oral absorption for drugs with pH-dependent solubility.

PubMed

Taniguchi, Chika; Kawabata, Yohei; Wada, Koichi; Yamada, Shizuo; Onoue, Satomi

2014-04-01

Drug release and oral absorption of drugs with pH-dependent solubility are influenced by the conditions in the gastrointestinal tract. In some cases, poor oral absorption has been observed for these drugs, causing insufficient drug efficacy. The pH-modification of a formulation could be a promising approach to overcome the poor oral absorption of drugs with pH-dependent solubility. The present review aims to summarize the pH-modifier approach and strategic analyses of microenvironmental pH for formulation design and development. We also provide literature- and patent-based examples of the application of pH-modification technology to solid dosage forms. For the pH-modification approach, the microenvironmental pH at the diffusion area can be altered by dissolving pH-modifying excipients in the formulation. The modulation of the microenvironmental pH could improve dissolution behavior of drugs with pH-dependent solubility, possibly leading to better oral absorption. According to this concept, the modulated level of microenvironmental pH and its duration can be key factors for improvement in drug dissolution. The measurement of microenvironmental pH and release of pH-modifier would provide theoretical insight for the selection of an appropriate pH-modifier and optimization of the formulation.

Solubility of drugs in the presence of gelatin: effect of drug lipophilicity and degree of ionization.

PubMed

Kallinteri, P; Antimisiaris, S G

2001-06-19

The solubility of seven drugs (nitrofurantoin, chlorothiazide, phenobarbital, prednisolone, griseofulvin, diazepam and piroxicam) in the absence and presence of gelatin was measured, at three different pH values (3.7, 5.0 and 7.0) at 37 degrees C. Drugs studied had different physicochemical properties (log P, pK(a), aqueous solubility) and their solubility in presence of 0.1 and 0.5% (w/v) hydrolyzed (and in some cases common) gelatin was estimated. Results show that the solubility of all drugs is significantly enhanced, especially in the presence of 0.5% gelatin. This gelatin-induced enhancement in drug solubility is higher in the pH in which acidic drugs are less ionized, especially for the less lipophilic acidic drugs (nitrofurantoin, chlorothiazide). In all cases, drug solubility in presence of gelatin is correlated with their aqueous solubility. Therefore, the established relationships between aqueous and gelatin solubility can be employed to derive an estimate of the drug solubility in presence of gelatin once its aqueous solubility is known. With the exception of piroxicam which is highly ionized and phenobarbital which is relatively soluble, there seems to be a tendency for larger gelatin-induced increases in solubility as drug lipophilicity increases or aqueous solubility decreases.

Influence of Acacia trees on soil nutrient levels in arid lands

NASA Astrophysics Data System (ADS)

De Boever, Maarten; Gabriels, Donald; Ouessar, Mohamed; Cornelis, Wim

2014-05-01

The potential of scattered trees as keystone structures in restoring degraded environments is gaining importance. Scattered trees have strong influence on their abiotic environment, mainly causing changes in microclimate, water budget and soil properties. They often function as 'nursing trees', facilitating the recruitment of other plants. Acacia raddiana is such a keystone species which persists on the edge of the Sahara desert. The study was conducted in a forest-steppe ecosystem in central Tunisia where several reforestation campaigns with Acacia took place. To indentify the impact of those trees on soil nutrients, changes in nutrient levels under scattered trees of three age stages were examined for the upper soil layer (0-10 cm) at five microsites with increasing distance from the trunk. In addition, changes in soil nutrient levels with depth underneath and outside the canopy were determined for the 0-30 cm soil layer. Higher concentrations of organic matter (OM) were found along the gradient from underneath to outside the canopy for large trees compared to medium and small trees, especially at microsites close to the trunk. Levels of soluble K, electrical conductivity (EC), available P, OM, total C and N decreased whereas pH and levels of soluble Mg increased with increasing distance from tree. Levels of soluble Ca and Na remained unchanged along the gradient. At the microsite closest to the trunk a significant decrease in levels of soluble K, EC, OM, available P, total C and N, while a significant increase in pH was found with increasing depth. The concentration of other nutrients remained unchanged or declined not differently underneath compared to outside the canopy with increasing depth. Differences in nutrient levels were largely driven by greater inputs of organic matter under trees. Hence, Acacia trees can affect the productivity and reproduction of understory species with the latter in term an important source of organic matter. This positive feedback mechanism is of crucial importance for soil nutrient conservation and the restoration of degraded arid environments.

Students' mental models on the solubility and solubility product concept

NASA Astrophysics Data System (ADS)

Rahmi, Chusnur; Katmiati, Siti; Wiji, Mulyani, Sri

2017-05-01

This study aims to obtain some information regarding profile of students' mental models on the solubility and solubility product concept. A descriptive qualitative method was the method employed in the study. The participants of the study were students XI grade of a senior high school in Bandung. To collect the data, diagnostic test on mental model-prediction, observation, explanation (TDM-POE) instrument was employed in the study. The results of the study revealed that on the concept of precipitation formation of a reaction, 30% of students were not able to explain the precipitation formation of a reaction either in submicroscopic or symbolic level although the microscopic have been shown; 26% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, but they were not able to explain the interaction of particles that involved in the reaction and to calculate Qsp; 26% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, and determine the particles involved, but they did not have the knowledge about the interactions occured and were uncapable of calculating Qsp; and 18% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, and determine the interactions of the particles involved in the reactions but they were not able to calculate Qsp. On the effect of adding common ions and decreasing pH towards the solubility concept, 96% of students were not able to explain the effect of adding common ions and decreasing pH towards the solubility either in submicroscopic or symbolic level although the microscopic have been shown; while 4% of students were only able to explain the effect of adding common ions towards the solubility based on the chemical equilibrium shifts and predict the effect of decreasing pH towards the solubility. However, they were not able to calculate the solubility before and after adding common ions and explain it up to the submicroscopic level either based on the shift of equilibrium solubility or the comparison of solubility calculation results before and after decreasing pH. Overall, the present study showed that most students obtain incomplete mental model on the solubility and solubility product concept. From the findings, it is recommended for the teachers to improve students' learning activity.

Effects of acid rain on grapevines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forsline, P.L.; Musselman, R.C.; Dee, R.J.

1983-01-01

Mature vineyard-growing Concord grapevines (Vitis labrusca, Bailey) were sprayed with simulated acid rain solutions ranging from pH 2.5 to pH 5.5 both as acute treatments at anthesis and chronically throughout the season in 1980 and 1981. In 1981, eight additional varieties were also treated with simulated acid rain solutions at pH 2.75 and pH 3.25. With Concord in 1981, few foliar lesions on leaves were visible at pH 2.75. In contrast, many leaf lesions with decreased fruit soluble solids in the absence of acid rain leaf lesions at pH>2.5 remains unclear. Acute sprays (pH 2.75) at anthesis reduced pollen germinationmore » in four grape cultivars. However, fruit set was reduced in only one of these. Only the cultivars de Chaunac and Ives had reduced berry soluble solids with chronic weekly sprays at pH 2.75. Reduction in soluble solids was not associated with increased oxidant stipple (ozone injury) in Concord and de Chaunac cultivars, but this association was observed in Ives. There was no evidence that acid rain in combination with ozone increased oxidant stipple as occurs when ozone and SO/sub 2/ are combined. Grape yields were not influenced by acid rain treatments. There was no evidence that acid rain at ambient pH levels had negative effects on grape production or fruit quality.« less

Acidogenic digestion of food waste in a thermophilic leach bed reactor: Effect of pH and leachate recirculation rate on hydrolysis and volatile fatty acid production.

PubMed

Hussain, Abid; Filiatrault, Mélissa; Guiot, Serge R

2017-12-01

The effect of pH control (4, 5, 6, 7) on volatile fatty acids (VFA) production from food waste was investigated in a leach bed reactor (LBR) operated at 50°C. Stabilisation of pH at 7 resulted in hydrolysis yield of 530g soluble chemical oxygen demand (sCOD)/kg total volatile solids (TVS) added and VFA yield of 247gCOD/kg TVS added, which were highest among all pH tested. Butyric acid dominated the VFA mix (49-54%) at pH of 7 and 6, while acetate composed the primary VFA (41-56%) at pH of 4 and 5. A metabolic shift towards lactic acid production was observed at pH of 5. Improving leachate recirculation rate further improved the hydrolysis and degradation efficiency by 10-16% and the acidification yield to 340gCOD/kgTVS added. The butyric acid concentration of 16.8g/L obtained at neutral pH conditions is among the highest reported in literature. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Soil acidification as a confounding factor on metal phytotoxicity in soils spiked with copper-rich mine wastes.

PubMed

Ginocchio, Rosanna; De la Fuente, Luz María; Sánchez, Pablo; Bustamante, Elena; Silva, Yasna; Urrestarazu, Paola; Rodríguez, Patricio H

2009-10-01

Pollution of soil with mine wastes results in both Cu enrichment and soil acidification. This confounding effect may be very important in terms of phytotoxicity, because pH is a key parameter influencing Cu solubility in soil solution. Laboratory toxicity tests were used to assess the effect of acidification by acidic mine wastes on Cu solubility and on root elongation of barley (Hordeum vulgare L.). Three contrasting substrates (two soils and a commercial sand) and two acidic, Cu-rich mine wastes (oxidized tailings [OxT] and smelter dust [SmD]) were selected as experimental materials. Substrates were spiked with a fixed amount of either SmD or OxT, and the pH of experimental mixtures was then modified in the range of 4.0 to 6.0 and 7.0 using PIPES (piperazine-1,4-bis(2-ethanesulfonic acid)), MES (2-(N-morpholino)ethanesulfonic acid), and MOPS (3-(N-Morpholino)-propanesulfonic acid) buffers. Chemical (pore-water Cu and pH) and toxicological (root length of barley plants) parameters were determined for experimental mixtures. Addition of SmD and OxT to substrates resulted in acidification (0.11-1.16 pH units) and high levels of soluble Cu and Zn. Neutralization of experimental mixtures with MES (pH 6.0) and MOPS (pH 7.0) buffers resulted in a marked decrease in soluble Cu and Zn, but the intensity of the effect was substrate-dependent. Adjustment of soil pH above the range normally considered to be toxic to plants (pH in water extract, > 5.5) significantly reduced metal toxicity in barley, but phytotoxicity was not completely eliminated. The present results stress the importance of considering confounding effects on derivation of toxicity thresholds to plants when using laboratory phytotoxicity tests.

Effects of organic solutes on chemical reactions of aluminum

USGS Publications Warehouse

Lind, Carol J.; Hem, John David

1975-01-01

Concentrations of organic matter in the general range of 1-10 milligrams per litre organic carbon are common in natural water, and many naturally occurrin7 organic compounds form aluminum complexes. The aluminum concentrations in near-neutral pH solutions may be 10-100 times higher than the values predicted from solubility data if formation of such organic complexes is ignored. The processes of polymerization of aluminum hydroxide and precipitation of gibbsite are inhibited by the presence of the organic flavone compound quercetin in concentrations as low as 10 x -5.3 mole per litre. Quercetin forms a complex, with a probable molar ratio of 1:2 aluminum to quercetin, that has a formation constant (f12) of about 10 12. A complex with a higher aluminum-quercetin ratio also was observed, but this material tends to evolve into a compound of low solubility that removes aluminum from solution. In the presence of both dissolved aluminum and aqueous silica, low concentrations of quercetin improved the yield of crystallized kaolinite and halloysite. Small amounts of well-shaped kaolinite and halloysite crystals were identified by electron microscopy in solutions with pH's in the range 6.5-8.5 after 155 days aging in one experimer t and 481 days aging in a repeated experiment. The bulk of the precipitated material was amorphous to X-rays, and crystalline material was too small a proportion of the total to give identifiable X-ray diffraction peaks. The precipitates had aluminum-silicon ratios near 1, and their solubility corresponded to that found by Hem, Roberson, Lind, and Polzer (1973) for similar aluminosilicate precipitated in the absence of organic solutes. The improved yield of crystalline material obtained in the presence of quercetin probably is the result of the influence of the organic compound on the aluminum hydroxide polymerization process. Natural water containing color imparted by organic material tends to be higher in aluminum than would be predicted by pH, silica concentrations, and solubility data for inorganic aluminum species.

Comparative study of the functional properties of three legume seed isolates: adzuki, pea and soy bean.

PubMed

Barac, Miroljub B; Pesic, Mirjana B; Stanojevic, Sladjana P; Kostic, Aleksandar Z; Bivolarevic, Vanja

2015-05-01

The aim of this work was to compare functional properties including solubility, emulsifying and foaming properties of native and thermally treated adzuki, soy and pea protein isolates prepared under the same conditions. These functional properties were tested at four pH values: pH 3.0, pH 5.0, pH 7.0 and pH 8.0. The lowest solubility at all pH values were obtained for isolate of adzuki whereas isolates of soybean had the highest values at almost all pHs. Thermal treatment reduced solubility of soy and pea isolates at all pH values, whereas solubility of adzuki isolate was unchanged, except at pH 8. Native isolate of adzuki had the best emulsifying properties at pH 7.0 whereas at the other pH values some of native pea and soybean protein isolates were superior. After thermal treatment, depending on tested pH and selected variety all of three species could be a good emulsifier. Native soy protein isolates formed the most stable foams at all pHs. Thermal treatment significantly improved foaming properties of adzuki isolate, whereas reduced foaming capacity of soy and pea isolates, but could improve foam stability of these isolates at specific pH. Appropriate selection of legume seed as well as variety could have great importance in achievement of desirable functional properties of final products. All three tested species could find specific application in wide range of food products.

Effects of alkali stress on growth, free amino acids and carbohydrates metabolism in Kentucky bluegrass (Poa pratensis).

PubMed

Zhang, Pingping; Fu, Jinmin; Hu, Longxing

2012-10-01

Soil alkalization is one of the most prominent adverse environmental factors limiting plant growth, while alkali stress affects amino acids and carbohydrates metabolism. The objective of this study was conducted to investigate the effects of alkali stress on growth, amino acids and carbohydrates metabolism in Kentucky bluegrass (Poa pratensis). Seventy-day-old plants were subjected to four pH levels: 6.0 (control), 8.0 (low), 9.4 (moderate) and 10.3 (severe) for 7 days. Moderate to severe alkali stress (pH >9.4) caused a significant decline in turf quality and growth rate in Kentucky bluegrass. Soluble protein was unchanged in shoots, but decreased in roots as pH increased. The levels of amino acids was kept at the same level as control level at 4 days after treatment (DAT) in shoots, but greater at 7 DAT, when plants were subjected to severe (pH 10.3) alkali stress. The alkali stressed plants had a greater level of starch, water soluble carbohydrate and sucrose content, but lower level of fructose and glucose. Fructan and total non-structural carbohydrate (TNC) increased at 4 DAT and decreased at 7 DAT for alkali stressed plants. These results suggested that the decrease in fructose and glucose contributed to the growth reduction under alkali stress, while the increase in amino acids, sucrose and storage form of carbohydrate (fructan, starch) could be an adaptative mechanism in Kentucky bluegrass under alkali stress.

Evaluation of chemical parameters in soft mold-ripened cheese during ripening by mid-infrared spectroscopy.

PubMed

Martín-del-Campo, S T; Picque, D; Cosío-Ramírez, R; Corrieu, G

2007-06-01

The suitability of mid-infrared spectroscopy (MIR) to follow the evolution throughout ripening of specific physicochemical parameters in Camembert-type cheeses was evaluated. The infrared spectra were obtained directly from raw cheese samples deposited on an attenuated total reflectance crystal. Significant correlations were observed between physicochemical data, pH, acid-soluble nitrogen, nonprotein nitrogen, ammonia (NH4+), lactose, and lactic acid. Dry matter showed significant correlation only with lactose and nonprotein nitrogen. Principal components analysis factorial maps of physicochemical data showed a ripening evolution in 2 steps, from d 1 to d 7 and from d 8 to d 27, similar to that observed previously from infrared spectral data. Partial least squares regressions made it possible to obtain good prediction models for dry matter, acid-soluble nitrogen, nonprotein nitrogen, lactose, lactic acid, and NH4+ values from spectral data of raw cheese. The values of 3 statistical parameters (coefficient of determination, root mean square error of cross validation, and ratio prediction deviation) are satisfactory. Less precise models were obtained for pH.

Harvest-time prediction of apple physiological indices using fiber optic Fourier transform near-infrared spectrometer

NASA Astrophysics Data System (ADS)

Liu, Yande; Ying, Yibin; Lu, Huishan; Fu, Xiaping

2004-12-01

This work evaluates the feasibility of Fourier transform near infrared (FT-NIR) spectrometry for rapid determining the total soluble solids content and acidity of apple fruit. Intact apple fruit were measured by reflectance FT-NIR in 800-2500 nm range. FT-NIR models were developed based on partial least square (PLS) regression and principal component regress (PCR) with respect to the reflectance and its first derivative, the logarithms of the reflectance reciprocal and its second derivative. The above regression models, related the FT-NIR spectra to soluble solids content (SSC), titratable acidity (TA) and available acidity (pH). The best combination, based on the prediction results, was PLS models with respect to the logarithms of the reflectance reciprocal. Predictions with PLS models resulted standard errors of prediction (SEP) of 0.455, 0.044 and 0.068, and correlation coefficients of 0.968, 0.728 and 0.831 for SSC, TA and pH, respectively. It was concluded that by using the FT-NIR spectrometry measurement system, in the appropriate spectral range, it is possible to nondestructively assess the maturity factors of apple fruit.

[Chemical forms and ecological effect of soil Mn in liver cancer's high incidence area in Zhu-jiang River Delta, China].

PubMed

Dou, Lei; Zhou, Yong-Zhang; Li, Yong; Ma, Jin; An, Yan-Fei; Du, Hai-Yan; Li, Zhan-Qiang

2008-06-01

The samples of surface soil, deep soil, and vegetables were collected from the liver cancer's high- and low incidence areas in Zhujiang River Delta to study the relationships between soil Mn forms and vegetables' Mn enrichment. The results showed that the soil Mn in study area was mainly derived from parent materials, and rarely come from human activities. The average soil Mn content in liver cancer's high incidence area was 577.65 mg x kg(-1), being significantly lower than that of liver cancer's low incidence area (718.04 mg x kg(-1)) and whole country (710 mg x kg(-1)). The Mn forms in high incidence area were mainly of residual Mn and Fe-Mn oxide, and less of water soluble Mn and exchangeable Mn, with the sum of the latter two's distribution coefficients being not higher than 4%. In low incidence area, the distribution pattern of soil Mn forms was similar to that in high incidence area, but the absolute contents of the Mn forms were significantly higher. Soil total Mn and soil pH had significant effects on soil Mn forms. There existed significant positive correlations between soil total Mn and the Mn forms of Fe-Mn bound, humic acid bound, carbonate bound, and residual, and negative correlations between soil pH and soil water soluble and organic bound Mn forms. Among the test five kinds of vegetables, Youmai lettuce and Chinese cabbage in liver cancer' s high incidence area had a significantly lower Mn content than in low incidence area, while the other three had less difference. The Mn enrichment in test vegetables was positively correlated with to the content of soil available Mn (sum of water soluble Mn and exchangeable Mn), but had no correlations with the contents of soil total Mn and other Mn forms.

Bioenergetics and the role of soluble cytochromes C for alkaline adaptation in gram-negative alkaliphilic Pseudomonas.

PubMed

Matsuno, T; Yumoto, I

2015-01-01

Very few studies have been conducted on alkaline adaptation of Gram-negative alkaliphiles. The reversed difference of H(+) concentration across the membrane will make energy production considerably difficult for Gram-negative as well as Gram-positive bacteria. Cells of the alkaliphilic Gram-negative bacterium Pseudomonas alcaliphila AL15-21(T) grown at pH 10 under low-aeration intensity have a soluble cytochrome c content that is 3.6-fold higher than that of the cells grown at pH 7 under high-aeration intensity. Cytochrome c-552 content was higher (64% in all soluble cytochromes c) than those of cytochrome c-554 and cytochrome c-551. In the cytochrome c-552-dificient mutant grown at pH 10 under low-aeration intensity showed a marked decrease in μ max⁡ [h(-1)] (40%) and maximum cell turbidity (25%) relative to those of the wild type. Considering the high electron-retaining abilities of the three soluble cytochromes c, the deteriorations in the growth of the cytochrome c-552-deficient mutant could be caused by the soluble cytochromes c acting as electron storages in the periplasmic space of the bacterium. These electron-retaining cytochromes c may play a role as electron and H(+) condenser, which facilitate terminal oxidation at high pH under air-limited conditions, which is difficult to respire owing to less oxygen and less H(+).

Bioenergetics and the Role of Soluble Cytochromes c for Alkaline Adaptation in Gram-Negative Alkaliphilic Pseudomonas

PubMed Central

Matsuno, T.; Yumoto, I.

2015-01-01

Very few studies have been conducted on alkaline adaptation of Gram-negative alkaliphiles. The reversed difference of H+ concentration across the membrane will make energy production considerably difficult for Gram-negative as well as Gram-positive bacteria. Cells of the alkaliphilic Gram-negative bacterium Pseudomonas alcaliphila AL15-21T grown at pH 10 under low-aeration intensity have a soluble cytochrome c content that is 3.6-fold higher than that of the cells grown at pH 7 under high-aeration intensity. Cytochrome c-552 content was higher (64% in all soluble cytochromes c) than those of cytochrome c-554 and cytochrome c-551. In the cytochrome c-552-dificient mutant grown at pH 10 under low-aeration intensity showed a marked decrease in μ max⁡ [h−1] (40%) and maximum cell turbidity (25%) relative to those of the wild type. Considering the high electron-retaining abilities of the three soluble cytochromes c, the deteriorations in the growth of the cytochrome c-552-deficient mutant could be caused by the soluble cytochromes c acting as electron storages in the periplasmic space of the bacterium. These electron-retaining cytochromes c may play a role as electron and H+ condenser, which facilitate terminal oxidation at high pH under air-limited conditions, which is difficult to respire owing to less oxygen and less H+. PMID:25705691

The effect of net charge on the solubility, activity, and stability of ribonuclease Sa.

PubMed

Shaw, K L; Grimsley, G R; Yakovlev, G I; Makarov, A A; Pace, C N

2001-06-01

The net charge and isoelectric pH (pI) of a protein depend on the content of ionizable groups and their pK values. Ribonuclease Sa (RNase Sa) is an acidic protein with a pI = 3.5 that contains no Lys residues. By replacing Asp and Glu residues on the surface of RNase Sa with Lys residues, we have created a 3K variant (D1K, D17K, E41K) with a pI = 6.4 and a 5K variant (3K + D25K, E74K) with a pI = 10.2. We show that pI values estimated using pK values based on model compound data can be in error by >1 pH unit, and suggest how the estimation can be improved. For RNase Sa and the 3K and 5K variants, the solubility, activity, and stability have been measured as a function of pH. We find that the pH of minimum solubility varies with the pI of the protein, but that the pH of maximum activity and the pH of maximum stability do not.

A modified physiological BCS for prediction of intestinal absorption in drug discovery.

PubMed

Zaki, Noha M; Artursson, Per; Bergström, Christel A S

2010-10-04

In this study, the influence of physiologically relevant media on the compound position in a biopharmaceutical classification system (BCS) which resembled the intestinal absorption was investigated. Both solubility and permeability limited compounds (n = 22) were included to analyze the importance of each of these on the final absorption. Solubility was determined in three different dissolution media, phosphate buffer pH 6.5 (PhB 6.5), fasted state simulated intestinal fluid (FaSSIF), and fed state simulated intestinal fluid (FeSSIF) at 37 °C, and permeability values were determined using the 2/4/A1 cell line. The solubility data and membrane permeability values were used for sorting the compounds into a BCS modified to reflect the fasted and fed state. Three of the seven compounds sorted as BCS II in PhB 6.5 (high permeability, low solubility) changed their position to BCS I when dissolved in FaSSIF and/or FeSSIF (high permeability, high solubility). These were low dosed (20 mg or less) lipophilic molecules displaying solvation limited solubility. In contrast, compounds having solid-state limited solubility had a minor increase in solubility when dissolved in FaSSIF and/or FeSSIF. Although further studies are needed to enable general cutoff values, our study indicates that low dosed BCS Class II compounds which have solubility normally restricted by poor solvation may behave as BCS Class I compounds in vivo. The large series of compounds investigated herein reveals the importance of investigating solubility and dissolution under physiologically relevant conditions in all stages of the drug discovery process to push suitable compounds forward, to select proper formulations, and to reduce the risk of food effects.

Evaluation of Matrix Tablets Based on Eudragit®E100/Carbopol®971P Combinations for Controlled Release and Improved Compaction Properties of Water Soluble Model Drug Paracetamol.

PubMed

Obeidat, Wasfy M; Nokhodchi, Ali; Alkhatib, Hatim

2015-10-01

The purpose of this work was to investigate the influence of Eudragit®E100 polymer in modifying the release rates and compaction properties of water soluble model drug paracetamol from Carbopol®971P NF polymer matrix tablets prepared by direct compression. The effects of the ratio of the two polymers, the total polymeric content, and the tablets mechanical strength on paracetamol release rates were investigated. Dissolution studies were conducted using USP XX Π rotating paddle apparatus at 50 rpm and 37°C at three different stages (pH 1.2, 4.8, and 6.8). Results showed that the polymers combination improved significantly the compaction properties of paracetamol tablets as evident by the higher crushing strengths (8.3 ± 0.4 Kp) compared to polymer-free tablets (3.4 ± 0.2 Kp) at intermediate compression pressure of 490 MPa. When combined with Carbopol®971P NF, Eudragit®E100 was found to be capable of extending paracetamol release for more than 12 h compared to 1 h for polymers-free tablets. The combined polymers were able to control paracetamol release in a pH independent pattern. The f2 (similarity factor) analysis showed that the ratio between the polymers and the total polymer concentration exhibited significant impact on drug release rates. In conclusion, Eudragit®E100 when combined with Carbopol®971P NF was capable of improving the compaction and sustained release properties of paracetamol. Korsmeyer-Peppas model was found to be the most suitable for fitting drug release data. The polymer combinations can potentially be used to control the release rates of highly water soluble drugs.

The dissolution of natural and artificial dusts in glutamic acid

NASA Astrophysics Data System (ADS)

Ling, Zhang; Faqin, Dong; Xiaochun, He

2015-06-01

This article describes the characteristics of natural dusts, industrial dusts, and artificial dusts, such as mineral phases, chemical components, morphological observation and size. Quartz and calcite are the main phases of natural dusts and industrial dusts with high SiO2 and CaO and low K2O and Na2O in the chemical composition. The dissolution and electrochemical action of dusts in glutamic acid liquor at the simulated human body temperature (37 °C) in 32 h was investigated. The potential harm that the dust could lead to in body glutamic acid acidic environment, namely biological activity, is of great importance for revealing the human toxicological mechanism. The changes of pH values and electric conductivity of suspension of those dusts were similar, increased slowly in the first 8 h, and then the pH values increased rapidly. The total amount of dissolved ions of K, Ca, Na, and Mg was 35.4 to 429 mg/kg, particularly Ca was maximal of 20 to 334 mg/kg. The total amount of dissolved ions of Fe, Zn, Mn, Pb, and Ba was 0.18 to 5.59 mg/kg and in Al and Si was 3.0 to 21.7 mg/kg. The relative solubility order of dusts in glutamic acid is wollastonite > serpentine > sepiolite, the cement plant industrial dusts > natural dusts > power plant industrial dusts. The wollastonite and cement plant industrial dusts have the highest solubility, which also have high content of CaO; this shows that there are a poorer corrosion-resisting ability and lower bio-resistibility. Sepiolite and power plant industrial dusts have lowest solubility, which also have high content of SiO2; this shows that there are a higher corrosion-resisting ability and stronger bio-resistibility.

Precipitation of a monoclonal antibody by soluble tungsten.

PubMed

Bee, Jared S; Nelson, Stephanie A; Freund, Erwin; Carpenter, John F; Randolph, Theodore W

2009-09-01

Tungsten microparticles may be introduced into some pre-filled syringes during the creation of the needle hole. In turn, these microcontaminants may interact with protein therapeutics to produce visible particles. We found that soluble tungsten polyanions formed in acidic buffer below pH 6.0 can precipitate a monoclonal antibody within seconds. Soluble tungsten in pH 5.0 buffer at about 3 ppm was enough to cause precipitation of a mAb formulated at 0.02 mg/mL. The secondary structure of the protein was near-native in the collected precipitate. Our observations are consistent with the coagulation of a monoclonal antibody by tungsten polyanions. Tungsten-induced precipitation should only be a concern for proteins formulated below about pH 6.0 since tungsten polyanions are not formed at higher pHs. We speculate that the heterogenous nature of particle contamination within the poorly mixed syringe tip volume could mean that a specification for tungsten contamination based on the entire syringe volume is not appropriate. The potential potency of tungsten metal contamination is highlighted by the small number of particles that would be required to generate soluble tungsten levels needed to coagulate this antibody at pH 5.0.

Precipitation of a Monoclonal Antibody by Soluble Tungsten

PubMed Central

Bee, Jared S.; Nelson, Stephanie A.; Freund, Erwin; Carpenter, John F.; Randolph, Theodore W.

2009-01-01

Tungsten microparticles may be introduced into some pre-filled syringes during the creation of the needle hole. In turn, these microcontaminants may interact with protein therapeutics to produce visible particles. We found that soluble tungsten polyanions formed in acidic buffer below pH 6.0 can precipitate a monoclonal antibody within seconds. Soluble tungsten in pH 5.0 buffer at about 3 ppm was enough to cause precipitation of a mAb formulated at 0.02 mg/mL. The secondary structure of the protein was near-native in the collected precipitate. Our observations are consistent with the coagulation of a monoclonal antibody by tungsten polyanions. Tungsten-induced precipitation should only be a concern for proteins formulated below about pH 6.0 since tungsten polyanions are not formed at higher pHs. We speculate that the heterogenous nature of particle contamination within the poorly mixed syringe tip volume could mean that a specification for tungsten contamination based on the entire syringe volume is not appropriate. The potential potency of tungsten metal contamination is highlighted by the small number of particles that would be required to generate soluble tungsten levels needed to coagulate this antibody at pH 5.0. PMID:19230018

Effect of electrical stunning frequency on meat quality, plasma parameters, and protein solubility of broilers.

PubMed

Huang, J C; Yang, J; Zhang, B H; Huang, M; Chen, K J; Xu, X L; Zhou, G H

2017-08-01

This study was designed to compare the effects of different stunning frequencies of pulsed direct current on meat quality of broilers. This was achieved by investigating plasma parameters, blood loss, carcass damage, meat water-holding capacity, meat color, meat shear value, muscle pH, and protein solubility. A total of 400 broilers was divided into 5 treatment groups and stunned with 500, 600, 700, 800, and 900 Hz at 15 V for 10 seconds. Blood samples were collected immediately after cutting the neck. Pectoralis major muscles were removed from the carcass after chilling and placed in ice. Breast muscle pH and meat color were determined at both 2 and 24 h postmortem. Drip loss, cooking loss, pressing loss, and cooked breast meat-shear values were determined at 24 h postmortem. Treatment at 500 and 900 Hz significantly increased (P < 0.05) blood plasma corticosterone and lactate concentrations compared with the 700 Hz group. The wing damage of carcasses was significantly serious in the 500, 800, and 900 Hz groups. The Pectoralis minor damage of carcesses in the 700 Hz group was significantly lower (P < 0.05) compared to the other stunning groups. The pH at 2 h postmortem in the 500 and 900 Hz groups was significantly lower (P < 0.05) than in other groups. However, the final pH and meat color were not affected by stunning frequency. In the 500 and 900 Hz groups, the protein solubility and shear force values were significantly lower (P < 0.05) and drip loss was significantly higher (P < 0.05) than in the 700 Hz group. This study indicates that the waveform of the pulsed direct current is acceptable for stunning broilers at a stunning frequency of 700 Hz. © 2017 Poultry Science Association Inc.

Effect of pressure on ore mineral solubilities under hydrothermal conditions.

USGS Publications Warehouse

Hemley, J.J.; Cygan, G.L.; d'Angelo, W. M.

1986-01-01

The combined solubilities of Fe, Zn and Pb sulphides were determined at elevated P and T in chloride solutions buffered in pH by a silicate assemblage of quartz monzonite composition plus added muscovite, and buffered in fS2 and fO2 by the assemblage pyrite-pyrrhotite-magnetite. Higher T and higher chloride concentration favour higher metal solubilities, but the P effect is opposite. At 500oC, 0.5 kbar and 1 M total chloride, Fe, Zn, Pb solubilities were 8500, 4300 and 8700 ppm, respectively, whereas at 1 kbar they were 4200, 2400 and 2600 ppm, and at 2 kbar, 1700, 800 and 1200 ppm. The P effect is of considerable importance to problems of ore-mineral transport; the metal could be carried over long distances on a decreasing P gradient so long as the T decreases were sufficient; this condition could be approximated by a near-adiabatic transport cooling path. Such a condition is probably common for hydrothermal processes involving fairly deep-seated sources of heat and mineral components.-L.C.H.

Recovery of soluble proteins from migratory locust (Locusta migratoria) and characterisation of their compositional and techno-functional properties.

PubMed

Purschke, Benedict; Tanzmeister, Helene; Meinlschmidt, Pia; Baumgartner, Sabine; Lauter, Kathrin; Jäger, Henry

2018-04-01

Edible insects emerged as an alternative source of high-quality proteins. Therefore, the effect of an extraction procedure for the recovery of migratory locust (Locusta migratoria) protein concentrate (MLPC) on the compositional characteristics and techno-functional properties was studied. The influence of pH value (2-10) and salt concentration (0, 1 and 3% w/v) on techno-functional properties was evaluated. Proteins were identified and characterized by RP-HPLC, SDS-PAGE and LC-MS/MS. The initial crude protein content of the whole locusts (65.9% on dry base) could be enhanced to 82.3% (MLPC). Solubility profiles of MLPC showed maximum solubility at pH9 (100%). Promising functionality comparable to egg white protein in terms of emulsifying activity at pH5, foamability at pH3 and 3% NaCl, and foam stability at pH9 were found. Consequently, MLPC offers a nutritious protein source with good functional properties at certain conditions, which could be used as food ingredient in a variety of food systems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhanced dissolution and bioavailability of Nateglinide by microenvironmental pH-regulated ternary solid dispersion: in-vitro and in-vivo evaluation.

PubMed

Wairkar, Sarika; Gaud, Ram; Jadhav, Namdeo

2017-09-01

Nateglinide, an Antidiabetic drug (BCS II), shows pH-dependent solubility and variable bioavailability. The purpose of study was to increase dissolution and bioavailability of Nateglinide by development of its microenvironmental pH-regulated ternary solid dispersion (MeSD). MeSD formulation of Nateglinide, poloxamer-188 and Na 2 CO 3 was prepared by melt dispersion in 1 : 2 : 0.2 w/w ratio and further characterised for solubility, In-vitro dissolution, microenvironmental pH, crystallinity/amorphism, physicochemical interactions, bioavailability in Wistar rats. Solubility of Nateglinide was increased notably in MeSD, and its in-vitro dissolution study showed fourfold increase in the dissolution, particularly in 1.2 pH buffer. Prominent reduction in the peak intensity of X-ray powder diffraction (XRPD) and absence of endotherm in DSC thermogram confirmed the amorphism of Nateglinide in MeSD. Attenuated total reflectance Fourier transform infrared spectra revealed the hydrogen bond interactions between Nateglinide and poloxamer-188. In-vivo study indicated that MeSD exhibited fourfold increase in area under curve over Nateglinide. Tmax of MeSD was observed at 0.25 h, which is beneficial for efficient management of postprandial sugar. Instead of mere transformation of the Nateglinide to its amorphous form as evidenced by DSC and XRPD, formation of a soluble carboxylate compound of Nateglinide in MeSD was predominantly responsible for dissolution and bioavailability enhancement. The study demonstrates the utility of MeSD in achieving pH-independent dissolution, reduced T max and enhanced bioavailability of Nateglinide. © 2017 Royal Pharmaceutical Society.

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.

Antibacterial Activity of Emulsified Pomelo (Citrus grandis Osbeck) Peel Oil and Water-Soluble Chitosan on Staphylococcus aureus and Escherichia coli.

PubMed

Chen, Guan-Wen; Lin, Yu-Hsin; Lin, Chia-Hua; Jen, Hsiao-Chin

2018-04-06

This study utilized pomelo steam distillation to isolate pomelo peel essential oil. The constituents were then analyzed through gas chromatography-mass spectrometry (GC-MS), and the antibacterial activity of the essential oil emulsions at different homogenizer speed conditions and concentrations of water-soluble chitosan (degree of acetylation, DA = 54.8%) against S. aureus and E. coli was examined. Analysis of the essential oil composition identified a total of 33 compounds with the main constituent, limonene accounting for 87.5% (940.07 mg/g) of the total. The pomelo peel oil was emulsified through homogenization at 24,000 rpm, resulting in a minimal inhibitory concentration (MIC) for E. coli that was 1.9 times lower than that of the essential oil without homogenization. In addition, a mixture of 0.4% essential oil emulsion and 0.03% water-soluble chitosan had the strongest synergetic antibacterial effect on S. aureus and E. coli at pH 7.4. In comparison with chitosan alone, the MIC value of this mixture was significantly 2.4 and 2.5 times lower. Hence, this study suggests using a mixture of emulsified pomelo peel oil and water-soluble chitosan to develop a novel natural food preservative, and that the processability of food, as well as the economic value of the byproducts of the Taiwan Matou pomelo and chitosan, could be increased.

Functional Properties of Pea (Pisum sativum, L.) Protein Isolates Modified with Chymosin

PubMed Central

Barać, Miroljub; Čabrilo, Slavica; Pešić, Mirjana; Stanojević, Slađana; Pavlićević, Milica; Maćej, Ognjen; Ristić, Nikola

2011-01-01

In this paper, the effects of limited hydrolysis on functional properties, as well as on protein composition of laboratory-prepared pea protein isolates, were investigated. Pea protein isolates were hydrolyzed for either 15, 30 and 60 min with recombined chymosin (Maxiren). The effect of enzymatic action on solubility, emulsifying and foaming properties at different pH values (3.0; 5.0; 7.0 and 8.0) was monitored. Chymosin can be a very useful agent for improvement of functional properties of isolates. Action of this enzyme caused a low degree of hydrolysis (3.9–4.7%), but improved significantly functional properties of pea protein isolates (PPI), especially at lower pH values (3.0–5.0). At these pH values all hydrolysates had better solubility, emulsifying activity and foaming stability, while longer-treated samples (60 min) formed more stable emulsions at higher pH values (7.0, 8.0) than initial isolates. Also, regardless of pH value, all hydrolysates showed improved foaming ability. A moderate positive correlation between solubility and emulsifying activity index (EAI) (0.74) and negative correlation between solubility and foam stability (−0.60) as well as between foam stability (FS) and EAI (−0.77) were observed. Detected enhancement in functional properties was a result of partial hydrolysis of insoluble protein complexes. PMID:22272078

Interactions between soy protein from water-soluble soy extract and polysaccharides in solutions with polydextrose.

PubMed

Spada, Jordana C; Marczak, Ligia D F; Tessaro, Isabel C; Cardozo, Nilo S M

2015-12-10

This study focuses on the investigation of the interactions between polysaccharides (carrageenan and carboxymethylcellulose--CMC) and soy proteins from the water-soluble soy extract. The influence of pH (2-7) and protein-polysaccharide ratio (5:1-40:1) on the interaction between these polyelectrolytes was investigated in aqueous solutions with 10% of polydextrose and without polydextrose. The studied systems were analyzed in terms of pH-solubility profile of protein, ζ-potential, methylene blue-polysaccharide interactions, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and confocal laser scanning microscopy. Although the mixtures of soy extract with both carrageenan and CMC showed dependency on the pH and protein-polysaccharide ratio, they did not present the same behavior. Both polysaccharides modified the pH-solubility profile of the soy protein, shifting the pH range in which the coacervate is formed to a lower pH region with the decrease of the soy extract-polysaccharide ratio. The samples also presented detectable differences regarding to ζ-potential, DSC, FTIR and microscopy analyses. The complex formation was also detected even in a pH range where both biopolymers were net-negatively charged. The changes promoted by the presence of polydextrose were mainly detected by blue-polysaccharide interactions measures and confocal microscopy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Complexation of sodium caseinate with gum tragacanth: Effect of various species and rheology of coacervates.

PubMed

Ghorbani Gorji, Sara; Ghorbani Gorji, Elham; Mohammadifar, Mohammad Amin; Zargaraan, Azizollaah

2014-06-01

We investigated complex coacervation of sodium caseinate/Astragalus rahensis (A.r) as a function of pH with light scattering, spectrophotometry, and viscosity measurements. Interestingly, sodium caseinate/A.r displayed five structural transitions; pH 7.00 to pH ∼5.40: no interaction occurred, pH ∼5.40 to pH ∼4.80: initiation of the formation of primary soluble complexes, pH ∼4.80 to ∼4.30: formation of interpolymer complexes, pH ∼4.30 to ∼4.02: optimum coacervation and pH ∼4.02 to ∼2.50: suppression of coacervation. In addition, rheological properties of sodium caseinate/A.r coacervates were studied at various pH values. A much higher storage modulus (G') than loss modulus (G″) for all sodium caseinate/A.r coacervates suggests the formation of highly interconnected gel-like network structures with mainly elastic behaviour. Moreover, sodium caseinate/A.r coacervates at all pH values exhibited a shear thinning behaviour across the entire shear rate range investigated. Effects of different species of gum tragacanth on the interactions with sodium caseinate have been scarcely studied. Our study showed that systems containing various species (A.r, soluble fraction of A.r and Astragalus gossypinus (A.g)) had different critical pH values and particle sizes during complex coacervation, which could be due to different ratio of soluble to insoluble fractions and uronic acid content of various species. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous in vitro and in vivo evaluation of both trimethoprim and sulfamethoxazole from certain dosage forms.

PubMed

Meshali, M; El-Sabbagh, H; Ghanem, A; Foda, A

1983-06-01

The dissolution rates of trimethoprim (T), and sulphamethoxazole (S), from different brands of tablets and suspensions were studied at pH = 1.1 and 7.2. The bioavailabilities of both drugs in humans were studied by the urine excretion method. The dissolution rates were dependent on the pH of the dissolution medium, the solubilities of the drugs at the pH involved, the dosage form and the brand studied. While the dissolution rates of T from all brands studied were consistent with their pH-dependent solubility, those of S were not. The dissolution rates of S from suspensions were found to be equal at pH = 7.2, but different at pH = 1.1. A correlation existed between the dissolution rate of T at pH = 1.1 from tablets and the excretion rate in humans. With S, however, no such correlation was observed at either pH.

Effect of chelators on functionality of milk protein concentrates obtained by ultrafiltration at a constant pH and temperature.

PubMed

Ramchandran, Lata; Luo, XiaoXia; Vasiljevic, Todor

2017-11-01

Modulating conditions during ultrafiltration of skim milk appears to be a feasible strategy to obtain milk protein concentrates (MPC) with tailored functionalities. Adjustment of pH and process temperature attenuated properties of casein micelle resulting in enhanced emulsification capacity. Additional pre-treatment options such as addition of calcium chelators can further impact on the functionality of MPC by modifying the calcium distribution and casein micelle integrity. The objective of the project was to establish effects of pre-treating skim milk with calcium chelators (EDTA or citrate) in concentrations between 10 to 30 mm prior to UF on the physical properties of the feed, corresponding retentates and dried MPC, including particle size, zeta potential and calcium distribution in skim milk and the corresponding retentates, as well as the physical functionalities such as solubility, heat stability and emulsifying properties. Addition of calcium chelators (EDTA or citrate), at levels 20-30 mm concentrations reduced casein micelle size as well as total, soluble and ionic calcium contents that resulted in MPC with enhanced solubility and heat stability. The emulsion capacity was, however, improved only with EDTA at 10 mm concentration. The enhanced functionality is attributed to the reduced particle size resulting from the removal of calcium from the retentate that could modify micellar casein to an extent sufficient to cause such improvements.

[Stability of anthocyanins in pasteurized juice of blackberry ((Rubus glaucus benth].

PubMed

Moreno-Alvarez, Mario José; Viloria Matos, Alfredo; López, Eliezer; Belén, Douglas

2002-06-01

In this research the chemical stability of total anthocyanins in three pasteurized juices elaborated from 12% of blackberry (Rubus glaucus Benth) pulp, and addition of ascorbic acid (Formulation A: 0.1%, Formulation B: 0.05% and Formulation C: 0.01%), was evaluated by means of absorption visible spectra (400-580 nm). Physicol-chemical characterization (acidity, soluble solids content in degree Brix, pH), and count of mesophilic microorganism, fungi, yeasts, fecal coliforms (PMN/mL) and Escherichia coli, were evaluated. Sensorial parameters (color, smell, flavor) were investigated by means of un-trained panel using a hedonic scale (Fridman, P < 0.05). The study was performed during storage for 9 days. The total anthocyanins were reported as pelargonidin-3-glycoside g/L, and no significant differences were founded among the evaluated in each formulation during storage (P > 0.05). Bactocromic effect due to oxidation as not observed. Acidity (6.0-7.2 mL NaOH 0.079 N), soluble solids content (9.0-9.8 degrees Brix) and pH (3.4) did not show significant differences (P > 0.05). The microbiological evaluation showed minimum values for pasturized products (fungi CFU/mL < 10, yeast CFU/mL < 10, fecal coliforms CFU/mL < 10 and mesophilic microorganism CFU/mL between 120-140 on first day in storage). Sensorial analysis did not show significant differences (Fridman, P > 0.05).

Aging of coprecipitated Cu in alumina: changes in structural location, chemical form, and solubility

NASA Astrophysics Data System (ADS)

Martínez, Carmen Enid; McBride, Murray B.

2000-05-01

The longterm fate of metals in mineral solid phases is not well established, as aging effects can alter metal forms and solubility. We use a model system (Cu coprecipitation with alumina) to examine copper solubility, chemical form, and structural location during longterm aging (up to 2 y), and as a function of Cu concentration, suspension pH, and rate of coprecipitate formation. Electron spin resonance (ESR) spectroscopy and extractability with EDTA were used to determine the chemical form and structural location of Cu in coprecipitates with alumina. Soluble Cu was measured by differential pulse anodic stripping voltammetry (dpasv) and alumina transformation monitored by XRD. Decreased Cu solubility resulted after prolonged aging of the coprecipitates formed at pH 6 and pH 7.5. Longterm aging (up to 2 y at 23°C) induced the transformation of an initially noncrystalline alumina to more ordered products including gibbsite. Results obtained by ESR and EDTA extraction indicate Cu movement towards the surface of the coprecipitate at increased aging time. Copper was initially evenly distributed within the alumina, but segregated at or near the alumina surface forming CuO and/or clusters after longterm reaction (2 y) with alumina.

Acacia gum as modifier of thermal stability, solubility and emulsifying properties of α-lactalbumin.

PubMed

de Oliveira, Fabíola Cristina; Dos Reis Coimbra, Jane Sélia; de Oliveira, Eduardo Basílio; Rodrigues, Marina Quadrio Raposo Branco; Sabioni, Rachel Campos; de Souza, Bartolomeu Warlene Silva; Santos, Igor José Boggione

2015-03-30

Protein-polysaccharide conjugates often display improved techno-functional properties when compared to their individual involved biomolecules. α-Lactalbumin:acacia gum (α-la:AG) conjugates were prepared via Maillard reaction by the dry-heating method. Conjugate formation was confirmed using results of absorbance, o-phthalaldehyde test, sodium dodecyl sulfate-polyacrilamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography. Techno-functional properties (emulsifying characteristics, solubility, and thermal stability) were evaluated for α-la, α-la/AG mixtures and α-la:AG conjugates. Conjugate thermal stability was improved compared to pure α-la treated at the same conditions of conjugate formation. Response surface methodology was used to establish models to predict solubility and emulsifying activity as functions of the salt concentration, pH and reaction time. α-la:AG conjugate solubility is affected in a complex manner by the three factors analyzed. Emulsifying activity index (EAI) of α-la is significantly affected by pH, while the α-la:AG EAI is affected by the three analyzed factors. Both solubility and EAI are maximized with pH 8.0, NaCl concentration of 0.3 mol L(-1) and two days of Maillard reaction. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of quick tests for phosphorus determination in dairy manures.

PubMed

Lugo-Ospina, A; Dao, Thanh H; Van Kessel, J A; Reeves, J B

2005-05-01

Nutrients in animal manure are valuable inputs in agronomic crop production. Rapid and timely information about manure nutrient content are needed to minimize the risks of phosphorus (P) over-application and losses of dissolved P (DP) in runoff from fields treated with manure. We evaluated the suitability of a commercial hand-held reflectometer, a hydrometer, and an electrical conductivity (EC) meter for determining DP and total P (TP) in dairy manures. Bulk samples (n = 107) collected from farms across CT, MD, NY, PA, and VA were highly variable in total solids (TS) concentration, ranging from 11 to 213gL(-1), in suspensions' pH (6.3-9.2), and EC (6.2-53.3 dS m(-1)). Manure DP concentrations measured using the RQFlex reflectometer (RQFlex-DP(s)) were related to molybdate-reactive P (MRP(s)) concentrations as follows: RQFlex-DP(s) = 0.471 x MRP(s) + 1102 (r2 = 0.29). Inclusion of pH and squared-pH terms improved the prediction of manure DP from RQFlex results (r2 = 0.66). Excluding five outlier samples that had pH < or = 6.9 the coefficient of determination (r2) for the MRP(s) and RQFlex-DP(s) relationship was 0.83 for 95% of the samples. Manure TS were related to hydrometer specific gravity readings (r2 = 0.53) that were in turn related to TP (r2 = 0.34), but not to either RQFlex-DP or MRP. Relationships between suspensions' EC and DP or TP were non-significant. Therefore, the RQFlex method is the only viable option for on-site quick estimates of DP that can be made more robust when complemented with TS and pH measurements. The DP quick test can provide near real-time information on soluble manure nutrient content across a wide range of handling and storage conditions on dairy farms and quick estimates of potential soluble P losses in runoff following land applications of manure.

Vesicular perylene dye nanocapsules as supramolecular fluorescent pH sensor systems.

PubMed

Zhang, Xin; Rehm, Stefanie; Safont-Sempere, Marina M; Würthner, Frank

2009-11-01

Water-soluble, self-assembled nanocapsules composed of a functional bilayer membrane and enclosed guest molecules can provide smart (that is, condition responsive) sensors for a variety of purposes. Owing to their outstanding optical and redox properties, perylene bisimide chromophores are interesting building blocks for a functional bilayer membrane in a water environment. Here, we report water-soluble perylene bisimide vesicles loaded with bispyrene-based energy donors in their aqueous interior. These loaded vesicles are stabilized by in situ photopolymerization to give nanocapsules that are stable over the entire aqueous pH range. On the basis of pH-tunable spectral overlap of donors and acceptors, the donor-loaded polymerized vesicles display pH-dependent fluorescence resonance energy transfer from the encapsulated donors to the bilayer dye membrane, providing ultrasensitive pH information on their aqueous environment with fluorescence colour changes covering the whole visible light range. At pH 9.0, quite exceptional white fluorescence could be observed for such water-soluble donor-loaded perylene vesicles.

Solubility of glucose isomerase in ammonium sulphate solutions

NASA Astrophysics Data System (ADS)

Chayen, N.; Akins, J.; Campbell-Smith, S.; Blow, D. M.

1988-07-01

In order to quantify protein crystallization techniques, a method for measuring protein solubility in high salt concentration has been developed. It is based on a sensitive protein concentration assay, using binding to Coomassie blue dye. The protein concentration in a supernatant from which glucose isomerase is crystallising has been studied as a function of time. Equilibrium is established in 3-5 weeks, and the protein concentration remaining in solution is defined as the solubility of the protein. The solubility of glucose isomerase has been determined as a function of ammonium sulphate concentration; its variation with pH in 1.50M ammonium sulphate has also been studied. A remarkable dependence on pH over the range of 5.5 to 6.5 has been observed.

Diblock Terpolymers Are Tunable and pH Responsive Vehicles To Increase Hydrophobic Drug Solubility for Oral Administration.

PubMed

Tale, Swapnil; Purchel, Anatolii A; Dalsin, Molly C; Reineke, Theresa M

2017-11-06

Synthetic polymers offer tunable platforms to create new oral drug delivery vehicles (excipients) to increase solubility, supersaturation maintenance, and bioavailability of poorly aqueous soluble pharmaceutical candidates. Five well-defined diblock terpolymers were synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT) and consist of a first block of either poly(ethylene-alt-propylene) (PEP), poly(N-isopropylacrylamide) (PNIPAm), or poly(N,N-diethylaminoethyl methacrylate) (PDEAEMA) and a second hydrophilic block consisting of a gradient copolymer of N,N-dimethylacrylamide (DMA) and 2-methacrylamidotrehalose (MAT). This family of diblock terpolymers offers hydrophobic, hydrophilic, or H-bonding functionalities to serve as noncovalent sites of drug binding. Drug-polymer spray dried dispersions (SDDs) were created with a model drug, probucol, and characterized by differential scanning calorimetry (DSC). These studies revealed that probucol crystallinity decreased with increasing H-bonding sites available in the polymer. The PNIPAm-b-P(DMA-grad-MAT) systems revealed the best performance at pH 6.5, where immediate probucol release and effective maintenance of 100% supersaturation was found, which is important for facilitating drug solubility in more neutral conditions (intestinal environment). However, the PDEAEMA-b-P(DMA-grad-MAT) system revealed poor probucol dissolution at pH 6.5 and 5.1. Alternatively, at an acidic pH of 3.1, a rapid and high dissolution profile and effective supersaturation maintenance of up to 90% of the drug was found, which could be useful for triggering drug release in acidic environments (stomach). The PEP-b-P(DMA-grad-MAT) system showed poor performance (only ∼20% of drug solubility at pH 6.5), which was attributed to the low solubility of the polymers in the dissolution media. This work demonstrates the utility of diblock terpolymers as a potential new excipient platform to optimize design parameters for triggered release and solubilizing hydrophobic drug candidates for oral delivery.

Effects of dietary tannins on total and extractable nutrients from manure.

PubMed

Halvorson, J J; Kronberg, S L; Hagerman, A E

2017-08-01

The effects of condensed tannins on N dynamics in ruminants have been a topic of research for some time, but much less work has focused on their impacts on other nutrients in manure. A 4 × 4 Latin square trial was used to determine if intake of sericea lespedeza (; SL; a condensed tannin source), at 0, 10, 20, or 40% of the diet (as-fed basis), would affect concentrations of nutrients in manure and patterns of total excretion when offered with alfalfa (; ALF) to sheep. With SL additions, average daily manure production increased linearly ( ≤ 0.01), from 40 to 50% of the diet mass. The concentrations of total C, total N, soluble P, total and soluble Na, total and soluble S, total and soluble Mn, and total and soluble B in feces increased ( ≤ 0.05) while soluble N, total Ca, total and soluble Mg, soluble Zn, total and soluble Fe, total and soluble Cu decreased ( ≤ 0.02). Total P, total and soluble K, soluble Ca, and total Zn were less affected ( > 0.05). Comparing diets containing 0 to 40% SL, average daily outputs of total C, total N, soluble P, soluble K, total and soluble Na, and total Mn increased linearly ( ≤ 0.01) by 42.0, 71.2, 93.3, 45.2, 111, 148, and 52.4 percentage points, respectively. Total K, total and soluble S, soluble Mn, and total and soluble B increased quadratically ( ≤ 0.02) by 26.1, 52.3, 26.7, 147, 100, and 19.5 percentage points, respectively. Conversely, outputs of soluble Zn and total Fe decreased linearly ( ≤ 0.01), by -51.5 and -24.8 percentage points, while total Ca, total and soluble Mg, soluble Fe, and soluble Cu decreased quadratically ( ≤ 0.05) by -15.7, -12.3, -40.0, -89.9, and -60.3 percentage points, respectively. Outputs of soluble N, total P, soluble Ca, total Zn, and total Cu remained unchanged ( ≥ 0.14). Ratios of manure outputs to feed inputs for C, N, K, and B increased ( ≤ 0.02) but those for P and Mg were unchanged ( ≥ 0.10). Ratios of soluble to total manure outputs (S:O) increased ( ≤ 0.01) for P, Ca, Na, Mn; decreased ( ≤ 0.05) for N, S, Mg, Zn, Fe, Cu, and B; and were unaffected by treatment ( ≤ 0.16) for K. Decreasing S:O ratios are consistent with the formation of complexes that adsorb these nutrients to insoluble fiber fractions of manure and could thus affect mineralization rates. This study suggests that dietary tannins, found in forages like SL, can alter the concentrations, total excretion rates and throughput efficiency of nutrients in manure.

Specific ion-protein interactions dictate solubility behavior of a monoclonal antibody at low salt concentrations.

PubMed

Zhang, Le; Zhang, Jifeng

2012-09-04

The perturbation of salt ions on the solubility of a monoclonal antibody was systematically studied at various pHs in Na(2)SO(4), NaNO(3), NaCl, NaF, MgSO(4), Mg(NO(3))(2) and MgCl(2) solutions below 350 mM. At pH 7.1, close to the pI, all of the salts increased the solubility of the antibody, following the order of SO(4)(2-) > NO(3)(-) > Cl(-) > F(-) for anions and Mg(2+) > Na(+) for cations. At pH 5.3 where the antibody had a net positive charge, the anions initially followed the order of SO(4)(2-) > NO(3)(-) > Cl(-) > F(-) for effectiveness in reducing the solubility and then switched to increasing the solubility retaining the same order. Furthermore, the antibody was more soluble in the Mg(2+) salt solutions than in the corresponding Na(+) salt solutions with the same anion. At pH 9.0 where the antibody had a net negative charge, an initial decrease in the protein solubility was observed in the solutions of the Mg(2+) salts and NaF, but not in the rest of the Na(+) salt solutions. Then, the solubility of the antibody was increased by the anions in the order of SO(4)(2-) > NO(3)(-) > Cl(-) > F(-). The above complex behavior is explained based on the ability of both cation and anion from a salt to modulate protein-protein interactions through their specific binding to the protein surface.

Pre-formulation studies of resveratrol

PubMed Central

Robinson, Keila; Mock, Charlotta; Liang, Dong

2015-01-01

Context Resveratrol, a natural compound found in grapes, has potential chemotherapy effects but very low oral bioavailability in humans. Objective To evaluate the solubility, pH stability profile, plasma protein binding (PPB) and stability in plasma for resveratrol. Methods Solubility of resveratrol was measured in 10 common solvents at 25 °C using HPLC. The solution state pH stability of resveratrol was assessed in various United States Pharmacopeia buffers ranging from pH 2 to 10 for 24 h at 37 °C. Samples were analyzed up to 24 h. Human PPB was determined using ultracentrifugation technique. Standard solutions of drug were spiked to blank human plasma to yield final concentrations of 5, 12.5 or 25 µg/mL for determination. Finally, stability of resveratrol in human and rat plasma was also assessed at 37 °C. Aliquots of blank plasma were spiked with a standard drug concentration to yield final plasma concentration of 50 µg/mL. Samples were analyzed for resveratrol concentration up to 96 h. Results Resveratrol has wide solubility ranging from 0.05 mg/mL in water to 374 mg/mL in polyethylene glycol 400 (PEG-400). Resveratrol is relatively stable above pH 6 and has maximum degradation at pH 9. The mean PPB of resveratrol is 98.3%. Resveratrol degrades in human and rat plasma in a first-order process with mean half lives of 54 and 25 h, respectively. Conclusion Resveratrol is more soluble in alcohol and PEG-400 and stable in acidic pH. It binds highly to plasma proteins and degrades slower in human then rat plasma. PMID:25224342

Probing the mechanisms of drug release from amorphous solid dispersions in medium-soluble and medium-insoluble carriers.

PubMed

Sun, Dajun D; Lee, Ping I

2015-08-10

The objective of the current study is to mechanistically differentiate the dissolution and supersaturation behaviors of amorphous drugs from amorphous solid dispersions (ASDs) based on medium-soluble versus medium-insoluble carriers under nonsink dissolution conditions through a direct head-to-head comparison. ASDs of indomethacin (IND) were prepared in several polymers which exhibit different solubility behaviors in acidic (pH1.2) and basic (pH7.4) dissolution media. The selected polymers range from water-soluble (e.g., PVP and Soluplus) and water-insoluble (e.g., ethylcellulose and Eudragit RL PO) to those only soluble in an acidic or basic dissolution medium (e.g., Eudragit E100, Eudragit L100, and HPMCAS). At 20wt.% drug loading, DSC and powder XRD analysis confirmed that the majority of incorporated IND was present in an amorphous state. Our nonsink dissolution results confirm that whether the carrier matrix is medium soluble determines the release mechanism of amorphous drugs from ASD systems which has a direct impact on the rate of supersaturation generation, thus in turn affecting the evolution of supersaturation in amorphous systems. For example, under nonsink dissolution conditions, the release of amorphous IND from medium-soluble carriers is governed by a dissolution-controlled mechanism leading to an initial surge of supersaturation followed by a sharp decline in drug concentration due to rapid nucleation and crystallization. In contrast, the dissolution of IND ASD from medium-insoluble carriers is more gradual as drug release is regulated by a diffusion-controlled mechanism by which drug supersaturation is built up gradually and sustained over an extended period of time without any apparent decline. Since several tested carrier polymers can be switched from soluble to insoluble by simply changing the pH of the dissolution medium, the results obtained here provide unequivocal evidence of the proposed transition of kinetic solubility profiles from the same ASD system induced by changes in the drug release mechanism in dissolution medium of a different pH. Copyright © 2015 Elsevier B.V. All rights reserved.

Improved dissolution and absorption of ketoconazole in the presence of organic acids as pH-modifiers.

PubMed

Adachi, Masashi; Hinatsu, Yuta; Kusamori, Kosuke; Katsumi, Hidemasa; Sakane, Toshiyasu; Nakatani, Manabu; Wada, Koichi; Yamamoto, Akira

2015-08-30

Formulation development of poorly water-soluble compounds can be challenging because of incomplete dissolution that causes low and variable bioavailability. Enhancing compound solubility is important and many techniques have been investigated to that end, but they require specific materials and machinery. This study investigates the incorporation of a pH-modifier as a method to increase compound solubility and uses ketoconazole (KZ), which is weakly basic (pKa: 6.5), as a model compound. Organic acids are effective pH-modifiers and are generally used in pharmaceutical industries. We successfully obtained granules containing variable organic acids (KZ/acid granule) using a high-shear mixer. Dissolution tests of the KZ/acid granule resulted in highly enhanced solubility under non-sink conditions. Adding water-soluble acids, such as citric acid (CA) and tartaric acid, resulted in more than 8-fold higher dissolution at pH 6.0 compared to that of KZ only. The granules containing citric acid (KZ/CA granule) improved the dissolution of KZ after oral administration to rats under low gastric acid conditions, where the bioavailability of the KZ/CA granules at elevated gastric pH was comparable with that of KZ only at gastric acidic pH. The incorporation of organic acids would result in effective therapeutic outcomes independent of gastric pH in patients. In addition, higher bioavailability of KZ was observed after oral administration of KZ/CA granules under gastric acidic pH conditions than that of KZ alone. Thus, CA improved the dissolution and absorption rate of KZ after oral administration. Copyright © 2015 Elsevier B.V. All rights reserved.

The effect of pH on metal accumulation in two Alyssum species.

PubMed

Kukier, Urszula; Peters, Carinne A; Chaney, Rufus L; Angle, J Scott; Roseberg, Richard J

2004-01-01

Nickel phytoextraction using hyperaccumulator plants offers a potential for profit while decontaminating soils. Although soil pH is considered a key factor in metal uptake by crops, little is known about soil pH effects on metal uptake by hyperaccumulator plants. Two Ni and Co hyperaccumulators, Alyssum murale and A. corsicum, were grown in Quarry muck (Terric Haplohemist) and Welland (Typic Epiaquoll) soils contaminated by a Ni refinery in Port Colborne, Ontario, Canada, and in the serpentine Brockman soil (Typic Xerochrepts) from Oregon, USA. Soils were acidified and limed to cover pH from strongly acidic to mildly alkaline. Alyssum grown in both industrially contaminated soils exhibited increased Ni concentration in shoots as soil pH increased despite a decrease in water-soluble soil Ni, opposite to that seen with agricultural crop plants. A small decrease in Alyssum shoot Ni concentration as soil pH increased was observed in the serpentine soil. The highest fraction of total soil Ni was phytoextracted from Quarry muck (6.3%), followed by Welland (4.7%), and Brockman (0.84%). Maximum Ni phytoextraction was achieved at pH 7.3, 7.7, and 6.4 in the Quarry, Welland, and Brockman soils, respectively. Cobalt concentrations in shoots increased with soil pH increase in the Quarry muck, but decreased in the Welland soil. Plants extracted 1.71, 0.83, and 0.05% of the total soil Co from Welland, Quarry, and Brockman, respectively. The differences in uptake pattern of Ni and Co by Alyssum from different soils and pH were probably related to the differences in organic matter and iron contents of the soils.

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

PubMed

Herhut, Marcel; Brandenbusch, Christoph; Sadowski, Gabriele

2016-02-01

Protein purification is often performed using cost-intensive chromatographic steps. To discover economic alternatives (e.g., crystallization), knowledge on protein solubility as a function of temperature, pH, and additives in solution as well as their concentration is required. State-of-the-art models for predicting protein solubility almost exclusively consider aqueous salt systems, whereas "salting-in" and "salting-out" effects induced by the presence of an additional polymer are not considered. Thus, we developed the sol-mxDLVO model. Using this newly developed model, protein solubility in the presence of one salt and one polymer, especially the non-monotonic course of protein solubility, could be predicted. Systems considered included salts (NaCl, Na-p-Ts, (NH(4))(2) SO(4)) and the polymer polyethylene glycol (MW: 2000 g/mol, 12000 g/mol) and proteins lysozyme from chicken egg white (pH 4 to 5.5) and D-xylose ketol-isomerase (pH 7) at 298.15 K. The results show that by using the sol-mxDLVO model, protein solubility in polymer-salt solutions can be modeled in good agreement with the experimental data for both proteins considered. The sol-mxDLVO model can describe the non-monotonic course of protein solubility as a function of polymer concentration and salt concentration, previously not covered by state-of-the-art models. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

pH treatment as an effective tool to select the functional and structural properties of yak milk caseins.

PubMed

Liu, H N; Zhang, C; Zhang, H; Guo, H Y; Wang, P J; Zhu, Y B; Ren, F Z

2013-09-01

Qula is made from yak milk after defatting, acidifying, and drying. Yak milk caseins are purified from Qula by dissolving in alkali solution. The effects of different pH treatments on the functional and structural properties of yak milk caseins were investigated. Over a broad range of pH (from 6.0 to 12.0), functional properties of yak milk caseins, including solubility, emulsifying activities, and thermal characteristics, and the structural properties, including 1-anilino-8-naphthalene-sulfonate fluorescence, turbidity and particle diameter, were evaluated. The results showed that the yak milk casein yield increased as the pH increased from 6.0 to 12.0. The solubility dramatically increased as the pH increased from 6.0 to 8.0, and decreased as the pH increased from 9.0 to 12.0. The changes in emulsifying activity were not significant. Caseins were remarkably heat stable at pH 9.0. The turbidity of the casein solution decreased rapidly as the pH increased from 6.0 to 12.0, and the results suggested that reassembled casein micelles were more compact at low pH than high pH. At pH values higher than 8.0, the yield of yak milk caseins reached more than 80%. The highest solubility was at pH 8.0, the best emulsification was at pH 10.0 and the greatest thermal stability was at pH 9.0. According to the functional characteristics of yak milk caseins, alkali conditions (pH 8.0-10.0) should be selected for optimum production. These results suggested that pH-dependent treatment could be used to modify the properties of yak milk caseins by appropriate selection of the pH level. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

POTENTIAL EFFECTS OF PHOSPHATE PRODUCTS ON LEAD SOLUBILITY IN PLUMBING SYSTEMS

EPA Science Inventory

Lead concentrations in drinking water can be minimized by adjusting the pH and alkalinity. Such lead solubility controls, however, may be offset by other water treatment measures that inadvertently increase lead solubility, e.g., the adding of polyphosphate-containing products. ...

Quality comparison of hydroponic tomatoes (Lycopersicon esculentum) ripened on and off vine

NASA Technical Reports Server (NTRS)

Arias, R.; Lee, T. C.; Specca, D.; Janes, H.

2000-01-01

There is a general belief that the quality of tomatoes ripened on vine is better than tomatoes ripened off the vine, influencing among other parameters, the price of this commodity. We compared the quality of hydroponic tomatoes ripened on and off vine by chemical, physical, and sensory evaluation to find what attributes are affected and to what extent. Lycopene, beta-carotene, total and soluble solids, moisture content, ascorbic acid, acidity, pH, texture, and color were analyzed. Tomatoes ripened on vine had significantly more lycopene, beta-carotene, soluble and total solids, higher a* and lower L*, and were firmer. However, a 100-judge panel rated only the color and overall liking of the vine-ripened tomatoes as more intense than the fruit ripened off vine. Therefore, the chemical and physical differences were mostly not large enough to influence the panelist's perception. The characterization of tomatoes ripened on and off vine may help to guide post-harvest handling and treatment and to improve the quality of tomatoes ripened off vine.

Physicochemical characterization of pure persimmon juice: nutritional quality and food acceptability.

PubMed

González, Eva; Vegara, Salud; Martí, Nuria; Valero, Manuel; Saura, Domingo

2015-03-01

Technological process for production of non-astringent persimmon (Diospyros kaki Thunb. cv. "Rojo Brillante") juice was described. The degree of fruit ripening expressed as color index (CI) varied between 12.37 and 16.33. Persimmon juice was characterized by determining physicochemical quality parameters as yield, total soluble solids (TSS), pH, titratable acidity (TA), organic acids, and main sugars. A thermal treatment of 90 ºC for 10 s was effective in controlling naturally occurring microorganisms for at least 105 d of storage without significantly affecting production of soluble brown pigments (BPs) and 5-hydroxymethyl furfural (5-HMF), total phenolic compounds (TPC), antioxidant capacity and acceptability of juice by panelists. Storage time affected all and each of the above parameters, reducing BPs, TPC and antioxidant capacity but increasing 5-HMF content. Refrigerated storage enhanced the acceptability of the juices. This information may be used by the juice industry as a starting point for production of pure persimmon juices. © 2015 Institute of Food Technologists®

Preformulation considerations for controlled release dosage forms. Part II. Selected candidate support.

PubMed

Chrzanowski, Frank

2008-01-01

Practical examples of preformulation support of the form selected for formulation development are provided using several drug substances (DSs). The examples include determination of the solubilities vs. pH particularly for the range pH 1 to 8 because of its relationship to gastrointestinal (GI) conditions and dissolution method development. The advantages of equilibrium solubility and trial solubility methods are described. The equilibrium method is related to detecting polymorphism and the trial solubility method, to simplifying difficult solubility problems. An example of two polymorphs existing in mixtures of DS is presented in which one of the forms is very unstable. Accelerating stability studies are used in conjunction with HPLC and quantitative X-ray powder diffraction (QXRD) to demonstrate the differences in chemical and polymorphic stabilities. The results from two model excipient compatibility methods are compared to determine which has better predictive accuracy for room temperature stability. A DSC (calorimetric) method and an isothermal stress with quantitative analysis (ISQA) method that simulates wet granulation conditions were compared using a 2 year room temperature sample set as reference. An example of a pH stability profile for understanding stability and extrapolating stability to other environments is provided. The pH-stability of omeprazole and lansoprazole, which are extremely unstable in acidic and even mildly acidic conditions, are related to the formulation of delayed release dosage forms and the resolution of the problem associated with free carboxyl groups from the enteric coating polymers reacting with the DSs. Dissolution method requirements for CR dosage forms are discussed. The applicability of a modified disintegration time (DT) apparatus for supporting CR dosage form development of a pH sensitive DS at a specific pH such as duodenal pH 5.6 is related. This method is applicable for DSs such as peptides, proteins, enzymes and natural products where physical observation can be used in place of a difficult to perform analytical method, saving resources and providing rapid preformulation support.

Improvement of drug loading onto ion exchange resin by cyclodextrin inclusion complex.

PubMed

Samprasit, Wipada; Rojanarata, Theerasak; Akkaramongkolporn, Prasert; Ngawhirunpat, Tanasait; Sila-on, Warisada; Opanasopit, Praneet

2013-11-01

Ion exchange resins have ability to exchange their counter ions for ionized drug in the surrounding medium, yielding "drug resin complex." Cyclodextrin can be applied for enhancement of drug solubility and stability. Cyclodextrin inclusion complex of poorly water-soluble NSAIDs, i.e. meloxicam and piroxicam, was characterized and its novel application for improving drug loading onto an anionic exchange resin, i.e. Dowex® 1×2, was investigated. β-Cyclodextrin (β-CD) and hydroxypropyl β-cyclodextrin (HP-β-CD) were used for the preparation of inclusion complex with drugs in solution state at various pH. The inclusion complex was characterized by phase solubility, continuous variation, spectroscopic and electrochemistry methods. Then, the drug with and without cyclodextrin were equilibrated with resin at 1:1 and 1:2 weight ratio of drug and resin. Solubility of the drugs was found to increase with increasing cyclodextrin concentration and pH. The increased solubility was explained predominantly due to the formation of inclusion complex at low pH and the increased ionization of drug at high pH. According to characterization studies, the inclusion complex was successfully formed with a 1:1 stoichiometry. The presence of cyclodextrin in the loading solution resulted in the improvement of drug loading onto resin. Enhancing drug loading onto ion-exchange resin via the formation of cyclodextrin inclusion complex is usable in the development of ion-exchange based drug delivery systems, which will beneficially reduce the use of harmful acidic or basic and organic chemicals.

Phase diagram of a crystalline protein: Determination of the solubility of concanavalin A by a microquantitation assay

NASA Astrophysics Data System (ADS)

Mikol, Vincent; Giegé, Richard

1989-09-01

A quick and miniature method has been devised for determining protein solubility and used to investigate the equilibrium solubility of concanavalin A from the Jack Bean with its crystals as a function of ammonium sulfate concentration, temperature and pH. The crystals were characterized by X-ray diffraction and their morphologies related to the corresponding solubilities. The protein solution concentration was estimated out of small crystallizing drops using a rapid and sensitive microassay. Measurements of protein quantity were carried out in 96-well microplates in an automatic spectrophotometer. The resulting phase diagram has permitted to analyse the solubility of concanavalin A, to estimate supersaturation and to devise readily new ways of crystal growth of this lectin, namely by pH and temperature variations. Moreover, the approach is proved to be a valuable tool to design crystallization experiments of new molecules and to improve and control protein crystal growth.

Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure: The effect of ammonia inhibition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Zhanguang; Zhou Xuefei; Zhang Yalei, E-mail: zhangyalei2003@163.com

Highlights: Black-Right-Pointing-Pointer Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure. Black-Right-Pointing-Pointer The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was key controlling factor. Black-Right-Pointing-Pointer The threshold of the SCOD/TAN ratio was 2.4 at an influent pH of 8.5-9. - Abstract: The effect of ammonia inhibition was evaluated during the enhanced anaerobic treatment of digested effluent from a 700 m{sup 3} chicken-manure continuous stirred tank reactor (CSTR). A 12.3 L internal circulation (IC) reactor inoculated with an anaerobic granular sludge and operated at 35 {+-} 1 Degree-Sign C was employed for the investigation. With a corresponding organic loading rate of 1.5-3.5more » kg-COD/m{sup 3} d over a hydraulic retention time of 1.5 d, a maximum volumetric biogas production rate of 1.2 m{sup 3}/m{sup 3} d and TCOD (total COD) removal efficiency ranging from 70% to 80% was achieved. However, the continual increase in the influent TAN content led to ammonia inhibition in the methanogenesis system. The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was presented to be the key controlling factor for the anaerobic treatment of semi-digested chicken manure, and further validation through shock loading and ammonia inhibition experiments was conducted. The threshold value of the SCOD/TAN ratio was determined to be 2.4 (corresponding to a TAN of 1250 mg/L) at an influent pH of 8.5-9.« less

Assessment of heat treatment of dairy products by MALDI-TOF-MS.

PubMed

Meltretter, Jasmin; Birlouez-Aragon, Inès; Becker, Cord-Michael; Pischetsrieder, Monika

2009-12-01

The formation of the Amadori product from lactose (protein lactosylation) is a major parameter to evaluate the quality of processed milk. Here, MALDI-TOF-MS was used for the relative quantification of lactose-adducts in heated milk. Milk was heated at a temperature of 70, 80, and 100 degrees C between 0 and 300 min, diluted, and subjected directly to MALDI-TOF-MS. The lactosylation rate of alpha-lactalbumin increased with increasing reaction temperature and time. The results correlated well with established markers for heat treatment of milk (concentration of total soluble protein, soluble alpha-lactalbumin and beta-lactoglobulin at pH 4.6, and fluorescence of advanced Maillard products and soluble tryptophan index; r=0.969-0.997). The method was also applied to examine commercially available dairy products. In severely heated products, protein pre-purification by immobilized metal affinity chromatography improved spectra quality. Relative quantification of protein lactosylation by MALDI-TOF-MS proved to be a very fast and reliable method to monitor early Maillard reaction during milk processing.

Effects of Comprehensive Technologies on the Improvement of Acidified Vineyard Soils

NASA Astrophysics Data System (ADS)

Jiang, Hongguo; Wang, Qiunan; Xu, Feng; Jin, Jun; Wang, Guoyu; Liu, Jianguo

2018-01-01

Soil acidification is an important factor that restricts the yield and quality of fruits. In this study, the comprehensive improving technologies were applied on the vineyards in which the soil pH is below 5.5. The technologies include application of soil conditioner, organic fertilizer and bacterial manure, and growth of green manure and natural grass. The results show that the comprehensive improving technologies can raise the pH of 0-15 cm soil layer by 0.5-0.8 unit and the pH of 15-30 cm soil layer by 0.3-0.6 unit. The soil bulk densities are decreased by 0.77-10.42%. The contents of organic matter, total N, available P and K in the soils are all increased. Therefore, the soil fertilities are improved. The yields of grape fruits are increased by 12.77-14.94%, and the contents of soluble solid in the grapes are raised by 7.01-9.55%, by the comprehensive measure of seaweed liquid silicon plus sheep manure plus growth of green manure. The comprehensive measure of soil conditioner Naduoli No. 1 plus bacterial manure plus natural grass increases the yields of grape by 7.67%, raises the content of soluble solid in the grape by 8.6%. But the effect of the comprehensive measure of unslaked lime plus sheep manure plus growth of green manure is not clear.

Application of Potential Phosphate-Solubilizing Bacteria and Organic Acids on Phosphate Solubilization from Phosphate Rock in Aerobic Rice

PubMed Central

Jusop, Shamshuddin; Naher, Umme Aminun; Othman, Radziah; Razi, Mohd Ismail

2013-01-01

A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB) and organic acids (oxalic & malic) on phosphate (P) solubilization from phosphate rock (PR) and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM), and PSB strain (Bacillus sp.) were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg−1), plant P uptake (0.78 P pot−1), and plant biomass (33.26 mg). Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g−1) compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH. PMID:24288473

Remediation of Cr(VI)-Contaminated Soil Using the Acidified Hydrazine Hydrate.

PubMed

Ma, Yameng; Li, Fangfang; Jiang, Yuling; Yang, Weihua; Lv, Lv; Xue, Haotian; Wang, Yangyang

2016-09-01

Acidified hydrazine hydrate was used to remediate Cr(VI)-contaminated soil. The content of water-soluble Cr(VI) in contaminated soil was 4977.53 mg/kg. The optimal initial pH of hydrazine hydrate solution, soil to solution ratio and molar ratio of Cr(VI) to hydrazine hydrate for remediation of Cr(VI)-contaminated soil were 5.0, 3:1 and 1:3, respectively. Over 99.50 % of water-soluble Cr(VI) in the contaminated soil was reduced at the optimal condition within 30 min. The remediated soil can keep stable within 4 months. Meanwhile the total phosphorus increased from 0.47 to 4.29 g/kg, indicating that using of acidified hydrazine hydrate is an effective method to remediate Cr(VI)-contaminated soil.

Trichomonas vaginalis: identification of soluble and membrane-associated phospholipase A1 and A2 activities with direct and indirect hemolytic effects.

PubMed

Vargas-Villarreal, Javier; Mata-Cárdenas, Benito David; Palacios-Corona, Rebeca; González-Salazar, Francisco; Cortes-Gutierrez, Elva I; Martínez-Rodríguez, Herminia G; Said-Fernández, Salvador

2005-02-01

A direct hemolytic activity, dependent on phospholipase A (PLA) activity, was located in the particulate subcellular fraction (P30) of Trichomonas vaginalis. We identified soluble direct and indirect hemolytic activities in the spent medium and soluble fraction (S30) of T. vaginalis strain GT-13. Spent medium showed the highest specific indirect hemolytic activity (SIHA) at pH 6.0 (91 indirect hemolytic units [HU]/mg/hr). Spent medium and P30, but not S30, showed direct hemolytic activity. PLA activity was protein dose dependent and time dependent. The highest PLA activity was observed at pH 6.0. All trichomonad preparations showed phospholipase A1 (PLA A1) and phospholipase A2 (PLA A2) activities. Indirect and direct hemolytic activity and PLA A1 and PLA A2 diminished at pH 6.0 and 8.0 with increasing concentrations of Rosenthal's inhibitor. The greatest effect was observed with 80 microM at pH 6.0 on the SIHA of S30 (83% reduction) and the lowest at pH 8.0, also on the SIHA of S30 (26% reduction). In conclusion, T. vaginalis contains particulate and soluble acidic, and alkaline direct and indirect hemolytic activities, which are partially dependent on alkaline or acidic PLA A1 and PLA A2 enzymes. These could be responsible for the contact-dependent and -independent hemolytic and cytolytic activities of T. vaginalis.

Studies on the production of alkaline α-amylase from Bacillus subtilis CB-18.

PubMed

Nwokoro, Ogbonnaya; Anthonia, Odiase

2015-01-01

Amylases are among the main enzymes used in food and other industries. They hydrolyse starch molecules into polymers composing glucose units. Amylases have potential applications in a number of industrial processes including foods and pharmaceutical industries. Alkaline α-amylase has the potential of hydrolysing starch under alkaline pH and is useful in the starch and textile industries and as an ingredient of detergents. Amylases are produced from plants, however, microbial production processes have dominated applications in the industries. Optimization of microbial production processes can result in improved enzyme yields. Amylase activity was assayed by incubating the enzyme solution (0.5 ml) with 1% soluble starch (0.5 ml) in 0.1 M Tris/HCl buffer (pH 8.5). After 30 minutes, the reaction was stopped by the addition of 4 mL of 3,5-dinitrosalicylic acid (DNS) reagent then heated for 10 min in boiling water bath and cooled in a refrigerator. Absorbance readings were used to estimate the units of enzyme activity from glucose standard curve. Hydrolysed native starches from cassava, rice, corn, coco yam, maize and potato and soluble starch were adjusted to pH 8.5 prior to incubation with crude enzyme solution. Reducing sugars produced were therefore determined. The effect of pH on enzyme activity of the alkaline α-amylase was determined by using buffer solutions of different pH (potassium phosphate buffer, 6.0-7.0; Tris-HCl buffer 7.5 to 9.0 and carbonate/bicarbonate buffer, pH 9.5-11) for enzyme assay. The pH stability profile of the enzyme was determined by incubating 0.5 ml of α-amylase enzyme in 0.1 M Tris/HCl buffer (pH 8.5) and 0.5 ml of 1% (w/v) soluble starch (Merck) in 0.1 M Tris/HCl buffer (pH 8.5) for 3 h in various buffers. The effect of temperature on enzyme activity was studied by incubating 0.5 mL of the enzyme solution contained in the test tube and 0.5 mL of 1% soluble starch (Merck) solution prepared in 0.1 M Tris/HCl buffer (pH 8.5) for 3 h at various temperatures (25, 30, 35, 40, 45, 50, 55 and 60°C) in a thermo static water bath. The reactions were stopped by adding DNS reagent. The enzyme activity was therefore determined. Thermal stability was studied by incubating 0.5 ml of enzyme solution in 0.1 M Tris/HCl buffer (pH 8.5) and 0.5 ml of 1% (w/v) soluble starch (Merck) in 0.1 M Tris/HCl buffer (pH 8.5) for 3 h at various temperatures (20, 30, 40, 50, 60 and 70°C) for 60 min. The enzyme displayed optimal activity at pH 8.0 at which it produced maximum specific activity of 34.3 units/mg protein. Maximum stability was at pH 8.0 to 9.0. Maximum activity was observed at temperature of 50°C while thermo stability of the enzyme was observed at 40-50°C. The enzyme displayed a wide range of activities on starch and caused the release of 5.86, 4.75, 5.98, 3.44, 3.96, 8.84 mg/mL reducing sugar from cassava, potato, cocoyam, corn, rice and soluble starch respectively. This investigation reports some biochemical characterization of alkaline α-amylase from Bacillus subtilis CB-18. The substrate specificities of this enzyme on various starches suggested that the alkaline α-amylase enzyme had combined activities on raw and soluble starch.

Factors controlling the solubility of trace metals in atmospheric aerosols over the Eastern Mediterranean

NASA Astrophysics Data System (ADS)

Nikolaou, Panagiota; Mihalopoulos, Nikolaos; Kanakidou, Maria

2015-04-01

Atmospheric input of aerosols is recognized, as an important source of nutrients, for the oceans. The chemical interactions between aerosols and varying composition of air masses lead to different coating of their surfaces with sulfate, nitrate and organic compounds, increasing their solubility and their role as a carrier of nutrients and pollutants in ecosystems. Recent works have highlighted that atmospheric inputs of nutrients and trace metals can considerably influence the marine ecosystem functioning at semi-enclosed or enclosed water bodies such as the eastern Mediterranean. The current work aims to determine the sources and the factors controlling the variability of nutrients in the eastern Mediterranean. Special focus has been given on trace elements solubility, considered either as key nutrients for phytoplankton growth such as iron (Fe), phosphorus (P) or inhibitors such as copper (Cu). This has been accomplished by analyzing size segregated aerosol samples collected at the background site of Finokalia in Crete for an entire year. Phosphorus concentrations indicate important increases in air masses influenced both by anthropogenic activities in the northeast European countries and by dust outbreaks. The last is confirmed by the correlation observed between total P and dust concentrations and by the air mass backward trajectories computed by running the NOAA Hysplit Model (Hybrid Single - Particle Langrangian Integrated Trajectory (http://www.arl.noaa.gov/ready/hysplit4.html). Overall 73% of total P has been found to be associated with anthropogenic sources. The solubility of P and Fe has been found to be closely related to the acidity (pH) and dust amount in aerosols. The aerosol pH was predicted using thermodynamic modeling (ISORROPIA-II), meteorological observations (RH, T), and gas/particle observations. More specifically P and Fe solubility appears to be inversely related to the crustal elements levels, while it increases in acidic environment. The significance of our findings for the eastern Mediterranean Sea is thoroughly discussed. This research has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: ARISTEIA - PANOPLY (Pollution Alters Natural Aerosol Composition: implications for Ocean Productivity, cLimate and air qualitY) grant.

Chemical speciation of cadmium: An approach to evaluate plant-available cadmium in Ecuadorian soils under cacao production.

PubMed

Chavez, E; He, Z L; Stoffella, P J; Mylavarapu, R S; Li, Y C; Baligar, V C

2016-05-01

Elevated concentration of cadmium (Cd) in cacao beans has raised serious concerns about the chocolate consumption on human health. Accumulation of Cd in cacao bean in southern Ecuador has been related to soil contamination. In this study, soil fractionation approach was used to identify available Cd pools in the soils and to correlate these Cd pools with bean Cd concentration and soil test indexes. The distribution of soil Cd fractions decreased in the order: oxidizable > acid-soluble > residual > reducible > water-soluble (+exchangeable). Oxidizable and acid-soluble fractions accounted for 59 and 68% of the total recoverable Cd for the 0-5 and 5-15 cm soil depth, respectively. Acid-soluble fraction was closely related to bean-Cd, with correlation coefficients (r) of 0.70 and 0.81 (P < 0.01) for the 0-5 and 5-15 cm soil depth, respectively. Acid-soluble Cd was significantly correlated with 0.01 M HCl- (r = 0.99, P < 0.01) or Mehlich 3- extractable Cd (r = 0.97, P < 0.01). These results indicate that acid-soluble Cd fraction is an important part of available Cd pool. Since approximately 60% of Cd in the cacao-growing soils is related to the acid-soluble fraction and bound to organic matter, remediation of the contaminated soils should consider to the dynamics of soil pH and organic matter content. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chewing activities and particle size of rumen digesta and feces of precision-fed dairy heifers fed different forage levels with increasing levels of distillers grains.

PubMed

Suarez-Mena, F X; Lascano, G J; Heinrichs, A J

2013-08-01

The objective of this study was to determine the effects of 2 differing forage to concentrate ratios (F:C) and various levels of corn dry distillers grain with solubles (DDGS) replacing canola meal in precision-fed dairy heifer rations on chewing behavior, rumen pH and fill, and particle size of rumen contents and feces. A split plot design with F:C as whole plot and DDGS inclusion level as subplot was administered in a 4-period 4 × 4 Latin square. Eight rumen-cannulated Holstein heifers (12.5±0.5 mo of age and 344±15 kg of body weight, respectively) housed in individual stalls were allocated to F:C 50:50 (low forage) or 75:25 [high forage (HF); dry matter basis] and to a sequence of DDGS level (0, 7, 14, and 21%; dry matter basis). Forage was a mix of 50% corn silage and 50% grass hay (dry matter basis). Diets were fed once daily and formulated to provide equal amounts of nutrients and body weight gain. No differences were found for rumen pH between dietary treatments. Time spent eating tended to be longer for HF and was not affected by DDGS inclusion rate. Ruminating time did not differ by F:C, but linearly increased as DDGS increased (422 to 450±21 min/d). Total chewing time tended to be longer for HF and to increase linearly as DDGS increased (553 to 579±33 min/d). Wet rumen digesta weight and volume were greater for HF. Geometric mean particle length of rumen contents was greater for HF 2h prefeeding when analyzed with solubles (particles <0.15 mm). Proportion of rumen solubles decreased as DDGS increased 5h postfeeding. Fecal geometric mean particle length and proportion of particles >1.18 mm increased with increasing levels of DDGS and did not change with F:C. Total chewing time increased by the addition of DDGS and higher F:C. Heifers can compensate for lower physically effective neutral detergent fiber by modifying their chewing behavior. Rumen pH was never at a level that could induce acidosis, and lower eating time at lower F:C was somewhat compensated by time spent ruminating per unit of physically effective neutral detergent fiber intake. Dry distillers grains with solubles, when used in dairy heifer rations as a replacement for canola meal, yielded similar rumen digestion traits. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Fate of 2,4,6-Trinitrotoluene in a Simulated Compost System

DTIC Science & Technology

1994-09-01

to the NaOH solution. The insoluble material remaining after the NaOH fractionation con- tained the humin fraction as well as remaining cellulose ...insoluble) (solb) HUMIN + CELLULOSE MIBK (insoluble) (MIBK) (aqueous) ICELLULOSE HUMIN HUMIC ACID + FULVIC ACID +HCI to pH 1 (insoLuble) (soluble...0.5 N NaOH (insoluble) (soluble) HUMIN+ CELLULOSE • MIBK (insoluble) (MIBK) (aqueous) CELLULOSE HUMIN HUMIC ACID + FULVIC ACID + HUMIN +HCl to pH 1

Transformation of Pb(II) from Cerrusite to Chloropyromorphite in the Presence of Hydroxyapatite under Varying Conditions of pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, J.A.; Zhang, P.

1998-10-14

Cerrusite (PbC03) is soluble under acidic conditions and considered to be a highly bioavailable soil Pb species. In this study, synthetic cerrusite and hydroxyapatite [Ca5(P04)30H] were reacted under constant and dynamic pH conditions with various P/Pb molar ratios in an attempt to evaluate the effect of reaction kinetics on the formation of chloropyromorphite (Pb5(P04)3Cl) and solubilization of Pb. Under constant pH conditions, dissolution rates of both cerrusite and apatite were rapid when pH was low. Complete conversion of Pb from cerrusite to chloropyromorphite occurred within 60 tin at pH 4 and below when the amount of phosphate in the addedmore » apatite was stoichoimetrically equal to that needed to transform all added Pb into chloropyromorphite. The concentration of soluble Pb depended upon the volubility of chloropyromorphite. The dissolution rates of apatite and cerrusite decreased with increasing pH, and the transformation was incomplete at pH 5 and above in the 60 rnin reaction period. The soluble Pb level, therefore, was determined by the volubility of cerrusite. In the dynamic pH system which simulated the gastrointestinal tract (GI tract) system, a complete transformation of Pb from cerrusite to chloropyromorphite was achieved due to the complete dissolution of apatite and cerrusite at the initial low pHs. Chloropyromorphite was the exclusive reaction product in both constant and dynamic pH systems as indicated by XRD analysis. The differences in transformation rate and the control of Pb volubility between the reactions occurring in constant and dynamic pH systems indicate the significance of kinetics in controlling the bioavailability of Pb and the potential for the reaction to occur during ingestion.« less

Product development studies of amino acid conjugate of Aceclofenac.

PubMed

Singh, Ajay Pal; Ramadan, Wafa Mossa; Dahiya, Rajiv; Sarpal, A S; Pathak, Kamla

2009-04-01

The prodrugs designed by classical approach increase lipophilicity of the drug, which decreases the water solubility thus decreasing the concentration gradient, which controls drug absorption. To overcome the limitations of traditional prodrug approach, water soluble prodrugs can be designed by adding selected amino acid to the drug moiety that are the substrates for the enzyme located at the intestinal brush border thus overcoming pharmaceutical problem without compromising bioavailability. ACaa (Amino acid conjugate of Aceclofenac) was synthesized by conjugation with l-phenylalanine by conventional coupling method using N, N-dicyclohexylcarbodiimide and ACaa was characterized by melting point, TLC, photomicrograph, UV, FT-IR, FT-NMR, MS-FAB, XRD and DSC. As a part of product development study ACaa was subjected to studies like In-vivo in albino rats and in-vitro like ACaa reversion to AC (Aceclofenac) in aqueous buffers of pH 1.21, 2.38. 3.10, 6.22 and 7.41, at a constant concentration (0.05M), ionic strength (micro = 0.5) and at a temperature of 37 degrees C +/- 0.5 degrees C, ACaa showed negligible reversion (2.15 %) up to 24 hrs study at acidic pH thus suggesting stability in acidic environment of stomach, the rate of reversion increased as pH of medium increased. pH- partition profile, pH- solubility profile and micromeritic studies were also carried out in comparison to pure drug. The solubility and lipophilicity of ACaa exhibited higher values at all pH range when compared to AC. The micromeritic properties also evaluated in terms of particle shape and size, IQCS and kurtosis. Resulting IQCS value approached zero thus suggesting reducing in the degree of skewness.

Cocrystal solubility product analysis - Dual concentration-pH mass action model not dependent on explicit solubility equations.

PubMed

Avdeef, Alex

2017-12-15

A novel general computational approach is described to address many aspects of cocrystal (CC) solubility product (K sp ) determination of drug substances. The CC analysis program, pDISOL-X, was developed and validated with published model systems of various acid-base combinations of active pharmaceutical ingredients (APIs) and coformers: (i) carbamazepine cocrystal systems with 4-aminobenzoic acid, cinnamic acid, saccharin, and salicylic acid, (ii) for indomethacin with saccharin, (iii) for nevirapine with maleic acid, saccharin, and salicylic acid, and (iv) for gabapentin with 3-hydroxybenzoic acid. In all systems but gabapentin, the coformer is much more soluble than the API. The model systems selected are those with available published dual concentration-pH data, one set for the API and one set for the coformer, generally measured at eutectic points (thermodynamically-stable three phases: solution, cocrystal, and crystalline API or coformer). The carbamazepine-cinnamic acid CC showed a substantial elevation in the API equilibrium concentration above pH5, consistent with the formation of a complex between carbamazepine and cinnamate anion. The analysis of the gabapentin:3-hydroxybenzoic acid 1:1 CC system indicated four zones of solid suspensions: coformer (pH<3.25), coformer and cocrystal eutectic (pH3.25-4.44), cocrystal (pH4.44-5.62), and API (pH>5.62). The general approach allows for testing of many possible equilibrium models, including those comprising drug-coformer complexation. The program calculates the ionic strength at each pH. From this, the equilibrium constants are adjusted for activity effects, based on the Stokes-Robinson hydration theory. The complete speciation analysis of the CC systems may provide useful insights into pH-sensitive dissolution effects that could potentially influence bioavailability. Copyright © 2017 Elsevier B.V. All rights reserved.

An empirical equation with tables of smoothed solubilities of methane in water and aqueous sodium chloride solutions up to 25 weight percent, 360 degrees C, and 138 MPa

USGS Publications Warehouse

Haas, John L.

1978-01-01

The total pressure for the system H2O-CH 4 is given by p(total) = P(H2O,t) + exp10[log x(CH 4) - a - b x(CH4)], where P(H2O,t) is the vapor pressure of H2O liquid at the temperature t (?C) and x(CH 4) is the molal concentration of methane in the solution. The terms a and b are functions of temperature only. Where the total pressure and temperature are known, the concentration of methane, x(CH4), is found by iteration. The concentration of methane in a sodium chloride brine, y(CH4), is estimated using the function log y(CH4) = log x(CH4) - A I, where A is the salting out constant and I is the ionic strength. For sodium chloride solutions, the ionic strength is equal to the molality of the salt. The equations are valid to 360?C, 138 MPa, and 25 weight percent sodium chloride.

Experimental determination of the hydrothermal solubility of ReS2 and the Re–ReO2 buffer assemblage and transport of rhenium under supercritical conditions

PubMed Central

Xiong, Yongliang; Wood, Scott A

2002-01-01

To understand the aqueous species important for transport of rhenium under supercritical conditions, we conducted a series of solubility experiments on the Re–ReO2 buffer assemblage and ReS2. In these experiments, pH was buffered by the K–feldspar–muscovite–quartz assemblage; in sulfur-free systems was buffered by the Re–ReO2 assemblage; and and in sulfur-containing systems were buffered by the magnetite–pyrite–pyrrhotite assemblage. Our experimental studies indicate that the species ReCl40 is dominant at 400°C in slightly acidic to near-neutral, and chloride-rich (total chloride concentrations ranging from 0.5 to 1.0 M) environments, and ReCl3+ may predominate at 500°C in a solution with total chloride concentrations ranging from 0.5 to 1.5 M. The results also demonstrate that the solubility of ReS2 is about two orders of magnitude less than that of ReO2. This finding not only suggests that ReS2 (or a ReS2 component in molybdenite) is the solubility-controlling phase in sulfur-containing, reducing environments but also implies that a mixing process involving an oxidized, rhenium-containing solution and a solution with reduced sulfur is one of the most effective mechanisms for deposition of rhenium. In analogy with Re, TcS2 may be the stable Tc-bearing phase in deep geological repositories of radioactive wastes.

Effect of composition of simulated intestinal media on the solubility of poorly soluble compounds investigated by design of experiments.

PubMed

Madsen, Cecilie Maria; Feng, Kung-I; Leithead, Andrew; Canfield, Nicole; Jørgensen, Søren Astrup; Müllertz, Anette; Rades, Thomas

2018-01-01

The composition of the human intestinal fluids varies both intra- and inter-individually. This will influence the solubility of orally administered drug compounds, and hence, the absorption and efficacy of compounds displaying solubility limited absorption. The purpose of this study was to assess the influence of simulated intestinal fluid (SIF) composition on the solubility of poorly soluble compounds. Using a Design of Experiments (DoE) approach, a set of 24 SIF was defined within the known compositions of human fasted state intestinal fluid. The SIF were composed of phospholipid, bile salt, and different pH, buffer capacities and osmolarities. On a small scale semi-robotic system, the solubility of 6 compounds (aprepitant, carvedilol, felodipine, fenofibrate, probucol, and zafirlukast) was determined in the 24 SIF. Compound specific models, describing key factors influencing the solubility of each compound, were identified. Although all models were different, the level of phospholipid and bile salt, the pH, and the interactions between these, had the biggest influences on solubility overall. Thus, a reduction of the DoE from five to three factors was possible (11-13 media), making DoE solubility studies feasible compared to single SIF solubility studies. Applying this DoE approach will lead to a better understanding of the impact of intestinal fluid composition on the solubility of a given drug compound. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of lime and compost on earthworm (Eisenia fetida) reproduction in copper and arsenic contaminated soils from the Puchuncaví Valley, Chile.

PubMed

Neaman, Alexander; Huerta, Soledad; Sauvé, Sébastien

2012-06-01

The Puchuncaví Valley in central Chile has been exposed to atmospheric depositions from a copper smelter. Nowadays, soils in the surrounding area are acidic and contaminated with Cu and As. The objective of this study was to determine the effectiveness of lime and compost for in situ immobilization of trace elements in the soils of the Puchuncaví Valley by using earthworms as bioindicators of toxicity. The lime and compost treatments significantly increased soil pH and decreased the soluble and exchangeable Zn, exchangeable Cu, and free Cu(2+) activity. However, the compost treatment increased soluble Cu, and soluble and exchangeable As. Lime application had no effect on earthworm reproduction in comparison with the unamended control, whereas the application of compost increased cocoon and juvenile production. There was a spatial variability of soil properties within treatments in the field plots. This allowed the identification of which soil properties were actually having an impact on earthworm reproduction. For both cocoon and juvenile production, soil organic matter (SOM) was a positive factor, i.e., more SOM increased cocoon or juvenile production. The toxicity (negative) factor was total soil As. However, total Cu and total As were well correlated (R(2)=0.80, p<0.001), hence some of the trends could have been masked. In summary, compost treatment was effective in improving the quality of soils of Puchuncaví Valley, increasing earthworm reproduction. Future Chilean legislation on maximum permissible concentrations of trace elements in soils should consider SOM content due to its effect on trace element solubility and bioavailability. Copyright © 2012 Elsevier Inc. All rights reserved.

Total chemical synthesis of human matrix Gla protein

PubMed Central

Hackeng, Tilman M.; Rosing, Jan; Spronk, Henri M.H.; Vermeer, Cees

2001-01-01

Human matrix Gla protein (MGP) is a vitamin K–dependent extracellular matrix protein that binds Ca2+ ions and that is involved in the prevention of vascular calcification. MGP is a 10.6-kD protein (84 amino acids) containing five γ-carboxyglutamic acid (Gla) residues and one disulfide bond. Studies of the mechanism by which MGP prevents calcification of the arterial media are hampered by the low solubility of the protein (<10 μg/mL). Because of solubility problems, processing of a recombinantly expressed MGP-fusion protein chimera to obtain MGP was unsuccessful. Here we describe the total chemical synthesis of MGP by tBoc solid-phase peptide synthesis (SPPS) and native chemical ligation. Peptide Tyr1-Ala53 was synthesized on a derivatized resin yielding a C-terminal thioester group. Peptide Cys54-Lys84 was synthesized on Lys-PAM resin yielding a C-terminal carboxylic acid. Subsequent native chemical ligation of the two peptides resulted in the formation of a native peptide bond between Ala53 and Cys54. Folding of the 1–84-polypeptide chain in 3 M guanidine (pH 8) resulted in a decrease of molecular mass from 10,605 to 10,603 (ESI-MS), representing the loss of two protons because of the formation of the Cys54-Cys60 internal disulfide bond. Like native MGP, synthetic MGP had the same low solubility when brought into aqueous buffer solutions with physiological salt concentrations, confirming its native like structure. However, the solubility of MGP markedly increased in borate buffer at pH 7.4 in the absence of sodium chloride. Ca2+-binding to MGP was confirmed by analytical HPLC, on which the retention time of MGP was reduced in the presence of CaCl2. Circular dichroism studies revealed a sharp increase in α-helicity at 0.2 mM CaCl2 that may explain the Ca2+-dependent shift in high-pressure liquid chromatography (HPLC)-retention time of MGP. In conclusion, facile and efficient chemical synthesis in combination with native chemical ligation yielded MGP preparations that can aid in unraveling the mechanism by which MGP prevents vascular calcification. PMID:11274477

Solubility of Nanocrystalline Cerium Dioxide: Experimental Data and Thermodynamic Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plakhova, Tatiana V.; Romanchuk, Anna Yu.; Yakunin, Sergey N.

For this study, ultrafine 5 nm ceria isotropic nanoparticles were prepared using the rapid chemical precipitation approach from cerium(III) nitrate and ammonium hydroxide aqueous solutions. The as-prepared nanoparticles were shown to contain predominantly Ce(IV) species. The solubility of nanocrystalline CeO 2 at several pH values was determined using ICP-MS and radioactive tracer methods. Phase composition of the ceria samples remained unchanged upon partial dissolution, while the shape of the particles changed dramatically, yielding nanorods under neutral pH conditions. According to X-ray absorption spectroscopy investigation of the supernatant, Ce(III) was the main cerium species in solution at pH < 4. Basedmore » on the results obtained, a reductive dissolution model was used for data interpretation. According to this model, the solubility product for ceria nanoparticles was determined to be log K sp = -59.3 ± 0.3 in 0.01 M NaClO 4. Taken together, our results show that the pH dependence of ceria anti- and pro-oxidant activity can be related to the dissolution of CeO 2 in aqueous media.« less

Solubility of Nanocrystalline Cerium Dioxide: Experimental Data and Thermodynamic Modeling

DOE PAGES

Plakhova, Tatiana V.; Romanchuk, Anna Yu.; Yakunin, Sergey N.; ...

2016-09-12

For this study, ultrafine 5 nm ceria isotropic nanoparticles were prepared using the rapid chemical precipitation approach from cerium(III) nitrate and ammonium hydroxide aqueous solutions. The as-prepared nanoparticles were shown to contain predominantly Ce(IV) species. The solubility of nanocrystalline CeO 2 at several pH values was determined using ICP-MS and radioactive tracer methods. Phase composition of the ceria samples remained unchanged upon partial dissolution, while the shape of the particles changed dramatically, yielding nanorods under neutral pH conditions. According to X-ray absorption spectroscopy investigation of the supernatant, Ce(III) was the main cerium species in solution at pH < 4. Basedmore » on the results obtained, a reductive dissolution model was used for data interpretation. According to this model, the solubility product for ceria nanoparticles was determined to be log K sp = -59.3 ± 0.3 in 0.01 M NaClO 4. Taken together, our results show that the pH dependence of ceria anti- and pro-oxidant activity can be related to the dissolution of CeO 2 in aqueous media.« less

Overexpression, purification, and characterization of SHPTP1, a Src homology 2-containing protein-tyrosine-phosphatase.

PubMed Central

Pei, D; Neel, B G; Walsh, C T

1993-01-01

A protein-tyrosine-phosphatase (PTPase; EC 3.1.3.48) containing two Src homology 2 (SH2) domains, SHPTP1, was previously identified in hematopoietic and epithelial cells. By placing the coding sequence of the PTPase behind a bacteriophage T7 promoter, we have overexpressed both the full-length enzyme and a truncated PTPase domain in Escherichia coli. In each case, the soluble enzyme was expressed at levels of 3-4% of total soluble E. coli protein. The recombinant proteins had molecular weights of 63,000 and 45,000 for the full-length protein and the truncated PTPase domain, respectively, as determined by SDS/PAGE. The recombinant enzymes dephosphorylated p-nitrophenyl phosphate, phosphotyrosine, and phosphotyrosyl peptides but not phosphoserine, phosphothreonine, or phosphoseryl peptides. The enzymes showed a strong dependence on pH and ionic strength for their activity, with pH optima of 5.5 and 6.3 for the full-length enzyme and the catalytic domain, respectively, and an optimal NaCl concentration of 250-300 mM. The recombinant PTPases had high Km values for p-nitrophenyl phosphate and exhibited non-Michaelis-Menten kinetics for phosphotyrosyl peptides. Images PMID:8430079

Acidogenic fermentation of Scenedesmus sp.-AMDD: Comparison of volatile fatty acids yields between mesophilic and thermophilic conditions.

PubMed

Gruhn, Marvin; Frigon, Jean-Claude; Guiot, Serge R

2016-01-01

This study compared the acidogenic fermentation of Scenedesmus sp.-AMDD at laboratory-scale, under mesophilic (35°C) and thermophilic conditions (55°C). Preliminary batch tests were performed to evaluate best conditions for volatile fatty acid (VFA) production from microalgal biomass, with respect to the inoculum, pH and nutrients. The use of bovine manure as inoculum, the operating pH of 4.5 and the addition of a nutrient mix, resulted in a high VFA production of up to 222mgg(-1) total volatile solid (TVS), with a butyrate share of 27%. Both digesters displayed similar hydrolytic activity with 0.38±0.02 and 0.42±0.03 g soluble chemical oxygen demand (COD)g(-1) TVS for the digesters operated at 35 and 55°C, respectively. Mesophilic conditions were more favorable for VFA production, which reached 171±5, compared to 88±12 mg soluble CODg(-1) TVS added under thermophilic conditions (94% more). It was shown that in both digesters, butyrate was the predominant VFA. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

pH of Aerosols in a Polluted Atmosphere: Source Contributions to Highly Acidic Aerosol.

PubMed

Shi, Guoliang; Xu, Jiao; Peng, Xing; Xiao, Zhimei; Chen, Kui; Tian, Yingze; Guan, Xinbei; Feng, Yinchang; Yu, Haofei; Nenes, Athanasios; Russell, Armistead G

2017-04-18

Acidity (pH) plays a key role in the physical and chemical behavior of PM 2.5 . However, understanding of how specific PM sources impact aerosol pH is rarely considered. Performing source apportionment of PM 2.5 allows a unique link of sources pH of aerosol from the polluted city. Hourly water-soluble (WS) ions of PM 2.5 were measured online from December 25th, 2014 to June 19th, 2015 in a northern city in China. Five sources were resolved including secondary nitrate (41%), secondary sulfate (26%), coal combustion (14%), mineral dust (11%), and vehicle exhaust (9%). The influence of source contributions to pH was estimated by ISORROPIA-II. The lowest aerosol pH levels were found at low WS-ion levels and then increased with increasing total ion levels, until high ion levels occur, at which point the aerosol becomes more acidic as both sulfate and nitrate increase. Ammonium levels increased nearly linearly with sulfate and nitrate until approximately 20 μg m -3 , supporting that the ammonium in the aerosol was more limited by thermodynamics than source limitations, and aerosol pH responded more to the contributions of sources such as dust than levels of sulfate. Commonly used pH indicator ratios were not indicative of the pH estimated using the thermodynamic model.

Arsenic removal from As-hyperaccumulator Pteris vittata biomass: Coupling extraction with precipitation.

PubMed

da Silva, Evandro B; de Oliveira, Letuzia M; Wilkie, Ann C; Liu, Yungen; Ma, Lena Q

2018-02-01

Proper disposal of As-hyperaccumulator Pteris vittata biomass (Chinese brake fern) enhances its application in phytoremediation. The goal of this study was to optimize As removal from P. vittata (PV) biomass by testing different particle sizes, extractants, extraction times and solid-to-liquid ratios. PV biomass was extracted using different extractants followed by different Mg-salts to recover soluble As via precipitation. Water-soluble As in PV biomass varied from 6.8% to 61% of total As depending on extraction time, with 99% of As being arsenate (AsV). Extraction with 2.1% HCl, 2.1% H 3 PO 4 , 1 M NaOH and 50% ethanol recovered 81, 78, 47 and 14% of As from PV biomass. A follow-up extraction using HCl recovered 27-32% with ethanol recovering only 5%. Though ethanol showed the lowest extractable As, residual As in the biomass was also the lowest. Among the extractants, 35% ethanol was the best to remove As from PV biomass. Approximately 90% As was removed from PV biomass using particle size <1 mm at solid:liquid ratio 1:50 and pH 6 for 2 h. Adding MgCl 2 at As:Mg ratio of 1:400 with pH 9.5 was effective to precipitate soluble As, resulting in 98% removal. Effective removal of As from PV biomass prior to disposal helps make phytoremediation more feasible. Published by Elsevier Ltd.

Treatment of low-strength soluble wastewater using an anaerobic baffled reactor (ABR).

PubMed

Gopala Krishna, G V T; Kumar, Pramod; Kumar, Pradeep

2009-01-01

Treatment of low-strength soluble wastewater (COD approximately 500 mg/L) was studied using an eight chambered anaerobic baffled reactor (ABR). At pseudo steady-state (PSS), the average total and soluble COD values (COD(T) and COD(S)) at 8h hydraulic retention time (HRT) were found to be around 50 and 40 mg/L, respectively, while at 10h HRT average COD(T) and COD(S) values were of the order of 47 and 37 mg/L, respectively. COD and BOD (3 day, 27 degrees C) removal averaged more than 90%. Effluent conformed to Indian standards laid down for BOD (less than 30 mg/L). Reactor effluent characteristics exhibited very low values of standard deviation indicating excellent reactor stability at PSS in terms of effluent characteristics. Based on mass balance calculations, more than 60% of raw wastewater COD was estimated to be recovered as CH(4) in the gas phase. Compartment-wise profiles indicated that most of the BOD and COD got reduced in the initial compartments only. Sudden drop in pH (7.8-6.7) and formation of volatile fatty acids (VFA) (53-85 mg/L) were observed in the first compartment due to acidogenesis and acetogenesis. The pH increased and VFA concentration decreased longitudinally down the reactor. Residence time distribution (RTD) studies revealed that the flow pattern in the ABR was neither completely plug-flow nor perfectly mixed. Observations from scanning electron micrographs (SEM) suggest that distinct phase separation takes place in an ABR.

Complexation of lead by Bermuda grass root exudates in aqueous media.

PubMed

Thomas, Catherine; Butler, Afrachanna; Larson, Steven; Medina, Victor; Begonia, Maria

2014-01-01

Exudates produced from Bermuda grass roots were collected in deionized water from sterilized Bermuda grass sod at 3-day intervals over a period of 15 days. Exudates were analyzed for total organic carbon, and characterized via Fourier Transform Infrared Spectroscopy. Exudate samples were adjusted to pH values of 4.5, 6.5, and 7.5, amended with lead and quantified for soluble and complexed lead via Inductively Coupled Plasma--Optical Emission Spectrometry. Data obtained from total organic carbon measurements indicated compositional changes in Bermuda grass root exudates as organic carbon concentrations increased over time. Analysis of the infrared spectroscopy data indicated that carboxylic acids and amine functional groups were present in root exudates. Also, the ability of root-exuded compounds to solubilize lead in aqueous media was demonstrated as exudate samples dissolved an average of 60% more lead than deionized water. At pH values 4.5 and 7.5, lead complexation by Bermuda grass root exudates increased with decreasing molecular weight size fractions, while an opposite trend was observed at pH 6.5. Results from this study demonstrated the ability of Bermuda grass root exudates to complex lead in aqueous media.

Preparation and characterization of fast dissolving flurbiprofen and esomeprazole solid dispersion using spray drying technique.

PubMed

Pradhan, Roshan; Tran, Tuan Hiep; Kim, Sung Yub; Woo, Kyu Bong; Choi, Yong Joo; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

2016-04-11

We aimed to develop an immediate-release flurbiprofen (FLU) and esomeprazole (ESO) combination formulation with enhanced gastric aqueous solubility and dissolution rate. Aqueous solubility can be enhanced by formulating solid dispersions (SDs) with a polyvinylpyrrolidone (PVP)-K30 hydrophilic carrier, using spray-drying technique. Aqueous and gastric pH dissolution can be achieved by macro-environmental pH modulation using sodium bicarbonate (NaHCO3) and magnesium hydroxide (Mg(OH)2) as the alkaline buffer. FLU/ESO-loaded SDs (FLU/ESO-SDs) significantly improved aqueous solubility of both drugs, compared to each drug powder. Dissolution studies in gastric pH and water were compared with the microenvironmental pH modulated formulations. The optimized FLU/ESO-SD powder formulation consisted of FLU/ESO/PVP-K30/sodium carbonate (Na2CO3) in a weight ratio 1:0.22:1.5:0.3, filled in the inner capsule. The outer capsule consisted of NaHCO3 and Mg(OH)2, which created the macro-environmental pH modulation. Increased aqueous and gastric pH dissolution of FLU and ESO from the SD was attributed to the alkaline buffer effects and most importantly, to drug transformation from crystalline to amorphous SD powder, clearly revealed by scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction studies. Thus, the combined FLU and ESO SD powder can be effectively delivered as an immediate-release formulation using the macro-environmental pH modulation concept. Copyright © 2016. Published by Elsevier B.V.

Positively Charged Nanostructured Lipid Carriers and Their Effect on the Dissolution of Poorly Soluble Drugs.

PubMed

Choi, Kyeong-Ok; Choe, Jaehyeog; Suh, Seokjin; Ko, Sanghoon

2016-05-20

The objective of this study is to develop suitable formulations to improve the dissolution rate of poorly water soluble drugs. We selected lipid-based formulation as a drug carrier and modified the surface using positively charged chitosan derivative (HTCC) to increase its water solubility and bioavailability. Chitosan and HTCC-coated lipid particles had higher zeta-potential values than uncoated one over the whole pH ranges and improved encapsulation efficiency. In vitro drug release showed that all NLC formulations showed higher in vitro release efficiency than drug particle at pH 7.4. Furthermore, NLC formulation prepared with chitosan or HTCC represented good sustained release property. The results indicate that chitosan and HTCC can be excellent formulating excipients of lipid-based delivery carrier for improving poorly water soluble drug delivery.

Chemical composition and physicochemical properties of Phaeodactylum tricornutum microalgal residual biomass.

PubMed

German-Báez, L J; Valdez-Flores, M A; Félix-Medina, J V; Norzagaray-Valenzuela, C D; Santos-Ballardo, D U; Reyes-Moreno, C; Shelton, L M; Valdez-Ortiz, A

2017-12-01

The production of photosynthetic biofuels using microalgae is a promising strategy to combat the use of non-renewable energy sources. The microalgae residual biomass is a waste by-product of biofuel production; however, it could prove to have utility in the development of sustainable nutraceuticals and functional foods. In this study, a comprehensive characterisation of the under-utilised Phaeodactylum tricornutum microalgae residual biomass is presented. Proximal composition, antioxidant capacity (using three different antioxidant assays; oxygen radical absorbance capacity; radical cation activity, ABTS; and radical scavenging activity, DPPH), and total phenolic content of free and bound polyphenols were determined. Additionally, the physicochemical properties of water activity, pH, water absorption index, water solubility index, and dispersibility were evaluated. Results revealed that P. tricornutum microalgae residual biomass exhibits a relatively high protein and carbohydrate content, with values of 36.67% and 46.78%, respectively; and most carbohydrates were found as total dietary fibre (45.57%), of which insoluble dietary fibre was the most predominant (43.54%). Antioxidant capacity values for total phytochemicals of 106.22, 67.93, 9.54 µM TE g -1 dw were determined by oxygen radical absorbance capacity, ABTS, and DPPH assays, respectively. Total phenolic content was found to be 2.90 mg GAE g -1 dw. Interestingly, antioxidant capacity and total phenolic content were higher in bound than in free phytochemical extracts. The physicochemical analysis showed P. tricornutum microalgae residual biomass to have suitable properties for the generation of a beverage with Aw, pH, water absorption index, water solubility index, and dispersibility values of 0.45, 7.12, 3.40 g gel g -1  dw, 2.5 g solids 100 g -1  dw, and 90%, respectively. Hence, P. tricornutum microalgae residual biomass could be considered a potential source of bioactive compounds suitable for the production of functional food exhibiting antioxidant capacity and high dietary fibre content.

Design Criteria for Process Wastewater Pretreatment Facilities

DTIC Science & Technology

1988-05-01

chamber where soluble trivalent chromium is formed. The trivalent chromium is then precipitated by raising the pH of the wastewater, usually through...lime addition at the mixing chamber outlet, and removed through claritication. The solubility of trivalent chromium is at a minimum near a solution pH... chromium e compounds are two of the dominant trivalent chromium species. -2 :.: -3- -4- 0 ,. -6 - -6- -7- -8 -a 9 - - .o -I1 - \\ ,.,’. -12 - Cro 2 - CrO3

Protease production by fermentation of fish solubles from salmon canning processes.

PubMed

Wah-On, H C; Branion, R M; Strasdine, G A

1980-09-01

Production of protease by fermentation, using Sorangium 495, of a substrate based on condensed fish solubles is demonstrated. The effects of carbohydrate addition, pH, fish solubles concentration, scale-up, agitation, and air flow rate on protease yields are described. While the fish solubles medium alone could give rise to measurable yields of protease, these were, at worst, doubled when 1% glucose was added to the medium. pH 7 was optimal for protease yield. Although the concentration of fish solubles in the basic medium showed no significant effect on cell yield, maximum protease yield was observed at a protein concentration equivalent to 3.85 mg/mL of bovine serum albumin. Protease production rates decreased as medium protein fermentor showed no significant effect on maximum protease yields. The effects of agitator speed and air flow rate on protease yield suggested that the rate of O2 transfer from air to medium could limit the rate of protease production. It was also noted that protease production is not growth associated.

Impact of Soil Composition and Electrochemistry on Corrosion of Rock-cut Slope Nets along Railway Lines in China.

PubMed

Chen, Jiao; Chen, Zhaoqiong; Ai, Yingwei; Xiao, Jingyao; Pan, Dandan; Li, Wei; Huang, Zhiyu; Wang, Yumei

2015-10-09

Taking the slope of Suiyu Railway to study, the research separately studied soil resistivity, soil electrochemistry (corrosion potential, oxidization reduction potential, electric potential gradient and pH), soil anions (total soluble salt, Cl(-), SO4(2-) and ), and soil nutrition (moisture content, organic matter, total nitrogen, alkali-hydrolysable nitrogen, available phosphorus, and available potassium) at different slope levels, and conducted corrosion grade evaluation on artificial soil according to its single index and comprehensive indexes. Compared with other factors, water has the biggest impact on the corrosion of slope protection net, followed by anion content. Total soluble salt has the moderate impact on the corrosion of slope protection net, and stray current has the moderate impact on the corrosion of mid-slope protection net. Comprehensive evaluation on the corrosive degree of soil samples indicates that the corrosion of upper slope is moderate, and the corrosion of mid-slope and lower slope is strong. Organic matter in soil is remarkably relevant to electric potential gradient. Available nitrogen, available potassium and available phosphorus are remarkably relevant to anions. The distribution of soil nutrient is indirectly relevant to slope type.

Impact of Soil Composition and Electrochemistry on Corrosion of Rock-cut Slope Nets along Railway Lines in China

PubMed Central

Chen, Jiao; Chen, Zhaoqiong; Ai, Yingwei; Xiao, Jingyao; Pan, Dandan; Li, Wei; Huang, Zhiyu; Wang, Yumei

2015-01-01

Taking the slope of Suiyu Railway to study, the research separately studied soil resistivity, soil electrochemistry (corrosion potential, oxidization reduction potential, electric potential gradient and pH), soil anions (total soluble salt, Cl−, SO42− and ), and soil nutrition (moisture content, organic matter, total nitrogen, alkali-hydrolysable nitrogen, available phosphorus, and available potassium) at different slope levels, and conducted corrosion grade evaluation on artificial soil according to its single index and comprehensive indexes. Compared with other factors, water has the biggest impact on the corrosion of slope protection net, followed by anion content. Total soluble salt has the moderate impact on the corrosion of slope protection net, and stray current has the moderate impact on the corrosion of mid-slope protection net. Comprehensive evaluation on the corrosive degree of soil samples indicates that the corrosion of upper slope is moderate, and the corrosion of mid-slope and lower slope is strong. Organic matter in soil is remarkably relevant to electric potential gradient. Available nitrogen, available potassium and available phosphorus are remarkably relevant to anions. The distribution of soil nutrient is indirectly relevant to slope type. PMID:26450811

Extending the applicability of pressurized hot water extraction to compounds exhibiting limited water solubility by pH control: curcumin from the turmeric rhizome.

PubMed

Euterpio, Maria Anna; Cavaliere, Chiara; Capriotti, Anna Laura; Crescenzi, Carlo

2011-11-01

Pressurized hot water extraction (PHWE, also known as subcritical water extraction) is commonly considered to be an environmentally friendly extraction technique that could potentially replace traditional methods that use organic solvents. Unfortunately, the applicability of this technique is often limited by the very low water solubility of the target compounds, even at high temperatures. In this paper, the scope for broadening the applicability of PHWE by adjusting the pH of the water used in the extraction is demonstrated in the extraction of curcumin (which exhibits very limited water solubility) from untreated turmeric (Curcuma longa L.) rhizomes. Although poor extraction yields were obtained, even at high temperatures when using degassed water or neutral phosphate buffer as the extraction medium, yields exceeding those obtained by Soxhlet extraction were achieved using highly acidic pH buffers due to curcumin protonation. The influence of the temperature, pH, and buffer concentration on the extraction yield were investigated in detail by means of a series of designed experiments. Optimized conditions for the extraction of curcumin from turmeric by PHWE were estimated at 197 °C using 62 g/L buffer concentration at pH 1.6. The relationships between these variables were subjected to statistical analysis using response surface methodology.

A Novel Water-soluble Ratiometric Fluorescent Probe Based on FRET for Sensing Lysosomal pH.

PubMed

Song, Guang-Jie; Bai, Su-Yun; Luo, Jing; Cao, Xiao-Qun; Zhao, Bao-Xiang

2016-11-01

A new ratiometric fluorescent probe based on Förster resonance energy transfer (FRET) for sensing lysosomal pH has been developed. The probe (RMPM) was composed of imidazo[1,5-α]pyridine quaternary ammonium salt fluorophore as the FRET donor and the rhodamine moiety as the FRET acceptor. It's the first time to report that imidazo[1,5-α]pyridine quaternary ammonium salt acts as the FRET donor. The ratio of fluorescence intensity of the probe at two wavelengths (I 424 /I 581 ) changed significantly and responded linearly toward minor pH changes in the range of 5.4-6.6. It should be noted that it's rare to report that a ratiometric pH probe could detect so weak acidic pH with pKa = 6.31. In addition, probe RMPM exhibited excellent water-solubility, fast-response, all-right selectivity and brilliant reversibility. Moreover, RMPM has been successfully applied to sensing lysosomal pH in HeLa cells and has low cytotoxicity.

Effects of the addition of nanoparticulate calcium carbonate on setting time, dimensional change, compressive strength, solubility and pH of MTA.

PubMed

Bernardi, A; Bortoluzzi, E A; Felippe, W T; Felippe, M C S; Wan, W S; Teixeira, C S

2017-01-01

To evaluate nanoparticulate calcium carbonate (NPCC) using transmission electron microscopy and the effects of NPCC addition to MTA in regard to the setting time, dimensional change, compressive strength, solubility and pH. The experimental groups were G1 (MTA), G2 (MTA with 5% NPCC) and G3 (MTA with 10% NPCC). The tests followed ISO and ADA standards. The specimens in the dimensional change and compressive strength tests were measured immediately after setting, after 24 h and after 30 days. In the solubility test, rings filled with cement were weighed after setting and after 30 days. The pH was measured after 24 h and 30 days. The data were analysed with the ANOVA, Tukey's and Kruskal-Wallis tests (α = 5%). The setting time was reduced (P < 0.05) in samples from G2 and G3 compared to G1. After 24 h, the dimensional change was similar amongst the groups, and after 30 days, G2 was associated with less alteration than G1 and G3. There was a difference in the compressive strength (P < 0.001) after 24 h and 30 days (G1 > G2 > G3). The solubility test revealed a difference amongst the groups when the specimens were hydrated: G2 > G1 > G3 and dehydrated: G3 > G2 > G1. The pH of the groups was similar at 24 h with higher values in each group after 30 days (P < 0.05), and G2 and G3 had similar mean pH values but both were higher than G1. Nanoparticulate calcium carbonate had a cubic morphology with few impurities. The addition of nanoparticulate calcium carbonate to MTA accelerated the setting time, decreased compressive strength and, after 30 days, resulted in lower dimensional change (G2), higher solubility and a higher pH. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Is the full potential of the biopharmaceutics classification system reached?

PubMed

Bergström, Christel A S; Andersson, Sara B E; Fagerberg, Jonas H; Ragnarsson, Gert; Lindahl, Anders

2014-06-16

In this paper we analyse how the biopharmaceutics classification system (BCS) has been used to date. A survey of the literature resulted in a compilation of 242 compounds for which BCS classes were reported. Of these, 183 compounds had been reported to belong to one specific BCS class whereas 59 compounds had been assigned to multiple BCS classes in different papers. Interestingly, a majority of the BCS class 2 compounds had fraction absorbed (FA) values >85%, indicating that they were completely absorbed after oral administration. Solubility was computationally predicted at pH 6.8 for BCS class 2 compounds to explore the impact of the pH of the small intestine, where most of the absorption occurs, on the solubility. In addition, the solubilization capacity of lipid aggregates naturally present in the intestine was studied computationally and experimentally for a subset of 12 compounds. It was found that all acidic compounds with FA>85% were completely dissolved in the pH of the small intestine. Further, lipids at the concentration used in fasted state simulated intestinal fluid (FaSSIF) dissolved the complete dose given of the most lipophilic (logD6.5>3) compounds studied. Overall, biorelevant dissolution media (pure buffer of intestinal pH or FaSSIF) identified that for 20 of the 29 BCS class 2 compounds with FA>85% the complete dose given orally would be dissolved. These results indicate that a more relevant pH restriction for acids and/or dissolution medium with lipids present better forecast solubility-limited absorption in vivo than the presently used BCS solubility criterion. The analysis presented herein further strengthens the discussion on the requirement of more physiologically relevant dissolution media for the in vitro solubility classification performed to reach the full potential of the BCS. Copyright © 2013 Elsevier B.V. All rights reserved.

Nitrifying aerobic granular sludge fermentation for releases of carbon source and phosphorus: The role of fermentation pH.

PubMed

Zou, Jinte; Pan, Jiyang; He, Hangtian; Wu, Shuyun; Xiao, Naidong; Ni, Yongjiong; Li, Jun

2018-07-01

The effect of fermentation pH (uncontrolled, 4 and 10) on the releases of carbon source and phosphorus from nitrifying aerobic granular sludge (N-AGS) was investigated. Meanwhile, metal ion concentration and microbial community characterization were explored during N-AGS fermentation. The results indicated that N-AGS fermentation at pH 10 significantly promoted the releases of soluble chemical oxygen demand (SCOD) and total volatile fatty acids (TVFAs). However, SCOD and TVFA released from N-AGS were inhibited at pH 4. Moreover, acidic condition promoted phosphorus release (mainly apatite) from N-AGS during anaerobic fermentation. Nevertheless, alkaline condition failed to increase phosphorus concentration due to the formation of chemical-phosphate precipitates. Compared with the previously reported flocculent sludge fermentation, N-AGS fermentation released more SCOD and TVFAs, possibly due to the greater extracellular polymeric substances content and some hydrolytic-acidogenic bacteria in N-AGS. Therefore, N-AGS alkaline fermentation facilitated the carbon source recovery, while N-AGS acidic fermentation benefited the phosphorus recovery. Copyright © 2018. Published by Elsevier Ltd.

Optimized conditions for MDCK permeability and turbidimetric solubility studies using compounds representative of BCS classes I-IV.

PubMed

Taub, Mitchell E; Kristensen, Lisbeth; Frokjaer, Sven

2002-05-01

The solubility enhancing effects of various excipients, including their compatibility with in vitro permeability (P(app)) systems, was investigated using drugs representative of Biopharmaceutics Classification System (BCS) classes I-IV. Turbidimetric solubility determination using nephelometry and transport experiments using MDCK Strain I cell monolayers were employed. The highest usable concentration of each excipient [dimethyl sulfoxide (DMSO), ethanol, hydroxypropyl-beta-cyclodextrin (HPCD), and sodium taurocholate] was determined by monitoring apical (AP) to basolateral (BL) [14C]mannitol apparent permeability (P(app)) and the transepithelial electrical resistance (TEER) in transport experiments done at pH 6.0 and 7.4. The excipients were used in conjunction with compounds demonstrating relatively low aqueous solubility (amphotericin B, danazol, mefenamic acid, and phenytoin) in order to obtain a drug concentration >50 microM in the donor compartment. The addition of at least one of the selected excipients enhanced the solubility of the inherently poorly soluble compounds to >50 microM as determined via turbidimetric evaluation at pH 6.0 and 7.4. Ethanol and DMSO were found to be generally disruptive to the MDCK monolayer and were not nearly as useful as HPCD and sodium taurocholate. Sodium taurocholate (5 mM) was compatible with MDCK monolayers under all conditions investigated. Additionally, a novel in vitro system aimed at more accurately simulating in vivo conditions, i.e., a pH gradient (6.0 AP/7.4 BL), sodium taurocholate (5 mM, AP), and bovine serum albumin (0.25%, BL), was shown to generate more reliable P(app) values for compounds that are poorly soluble and/or highly protein bound.

Substitution of wheat dried distillers grains with solubles for barley grain or barley silage in feedlot cattle diets: intake, digestibility, and ruminal fermentation.

PubMed

Li, Y L; McAllister, T A; Beauchemin, K A; He, M L; McKinnon, J J; Yang, W Z

2011-08-01

The objective of this study was to evaluate the effects of substituting wheat dried distillers grains with solubles (DDGS) for barley grain and barley silage on intake, digestibility, and ruminal fermentation in feedlot beef cattle. Eight ruminally cannulated Angus heifers (initial BW 455 ± 10.8 kg) were assigned to a replicated 4 × 4 Latin square design with 4 treatments: control, low (25%), medium (30%), and high (35%) wheat DDGS (DM basis). The diets consisted of barley silage, barley concentrate, and wheat DDGS in ratios of 15:85:0 (CON), 10:65:25 (25DDGS), 5:65:30 (30DDGS), and 0:65:35 (35DDGS; DM basis), respectively. The diets were formulated such that wheat DDGS was substituted for both barley grain and barley silage to evaluate whether wheat DDGS can be fed as a source of both energy (grain) and fiber in feedlot finishing diets. Intakes (kg/d) of DM and OM were not different, whereas those of CP, NDF, ADF, and ether extract (EE) were greater (P < 0.01) and intake of starch was less (P < 0.01) for the 25DDGS compared with the CON diet. The digestibilities of CP, NDF, ADF, and EE in the total digestive tract were greater (P < 0.05) for 25DDGS vs. CON. Ruminal pH and total VFA concentrations were not different (P > 0.15) between 25DDGS and CON diets. Replacing barley silage with increasing amounts of wheat DDGS (i.e., from 25DDGS to 35DDGS) linearly reduced (P < 0.05) intakes of DM and other nutrients without altering (P=0.40) CP intake. In contrast, digestibilities of DM and other nutrients in the total digestive tract linearly increased (P < 0.05) with increasing wheat DDGS except for that of EE. Additionally, with increasing amounts of wheat DDGS, mean ruminal pH tended (P=0.10) to linearly decrease, and ruminal pH status decreased with longer (P=0.04) duration of pH <5.5 and <5.2, and greater (P=0.01) curve area under pH <5.8 and <5.5 without altering (P > 0.19) ruminal VFA and NH(3)-N concentrations. Results indicated that wheat DDGS can be effectively used to replace both barley grain and silage at a moderate amount to meet energy and fiber requirements of finishing cattle. However, when silage content of the diet is low (<10%), wheat DDGS is not an effective fiber source, so replacing forage fiber with wheat DDGS in finishing diets decreases overall ruminal pH status even though the rapidly fermentable starch content of the diet is considerably reduced. © 2011 American Society of Animal Science. All rights reserved.

Composition of Ragusano cheese during aging.

PubMed

Licitra, G; Campo, P; Manenti, M; Portelli, G; Scuderi, S; Carpino, S; Barbano, D M

2000-03-01

Ragusano cheese is a brine-salted pasta filata cheese. Composition changes during 12 mo of aging were determined. Historically, Ragusano cheese has been aged in caves at 14 to 16 degrees C with about 80 to 90% relative humidity. Cheeses (n = 132) included in our study of block-to-block variation were produced by 20 farmhouse cheese makers in the Hyblean plain region of the Province of Ragusa in Sicily. Mean initial cheese block weight was about 14 kg. The freshly formed blocks of cheese before brine salting contained about 45.35% moisture, 25.3% protein, and 25.4% fat, with a pH of 5.25. As result of the brining and aging process, a natural rind forms. After 12 mo of aging, the cheese contained about 33.6% moisture, 29.2% protein, 30.0% fat, and 4.4% salt with a pH of 5.54, but block-to-block variation was large. Both soluble nitrogen content and free fatty acid (FFA) content increased with age. The pH 4.6 acetate buffer and 12% TCA-soluble nitrogen as a percentage of total nitrogen were 16 and 10.7%, respectively, whereas the FFA content was about 643 mg/100 g of cheese at 180 d. Five blocks of cheese were selected at 180 d for a study of variation within block. Composition variation within block was large; the center had higher moisture and lower salt in moisture content than did the outside. Composition variation within blocks favored more proteolysis and softer texture in the center.

Characterization of Proteus vulgaris K80 lipase immobilized on amine-terminated magnetic microparticles.

PubMed

Natalia, Agnes; Kristiani, Lidya; Kim, Hyung Kwoun

2014-10-01

Proteus vulgaris K80 lipase was expressed in Escherichia coli BL21 (DE3) cells and immobilized on amine-terminated magnetic microparticles (Mag-MPs). The immobilization yield and activity retention were 84.15% and 7.87%, respectively. A homology model of lipase K80 was constructed using P. mirabilis lipase as the template. Many lysine residues were located on the protein surface, remote from active sites. The biochemical characteristics of immobilized lipase K80 were compared with the soluble free form of lipase K80. The optimum temperature of K80-Mag-MPs was 60°C, which was 20°C higher than that of the soluble form. K80-Mag-MPs also tended to be more stable than the soluble form at elevated temperatures and a broad range of pH. K80-Mag-MP maintained its stable form at up to 40°C and in a pH range of 5.0- 10.0, whereas soluble K80 maintained its activity up to 35°C and pH 6.0-10.0. K80-Mag-MPs had broader substrate specificity compared with that of soluble K80. K80-Mag-MPs showed about 80% residual relative activity after five recovery trials. These results indicate the potential benefit of K80-Mag-MPs as a biocatalyst in various industries.

In silico and in vitro prediction of gastrointestinal absorption from potential drug eremantholide C.

PubMed

Caldeira, Tamires G; Saúde-Guimarães, Dênia A; Dezani, André B; Serra, Cristina Helena Dos Reis; de Souza, Jacqueline

2017-11-01

Analysis of the biopharmaceutical properties of eremantholide C, sesquiterpene lactone with proven pharmacological activity and low toxicity, is required to evaluate its potential to become a drug. Preliminary analysis of the physicochemical characteristics of eremantholide C was performed in silico. Equilibrium solubility was evaluated using the shake-flask method, at 37.0 °C, 100 rpm during 72 h in biorelevant media. The permeability was analysed using parallel artificial membrane permeability assay, at 37.0 °C, 50 rpm for 5 h. The donor compartment was composed of an eremantholide C solution in intestinal fluid simulated without enzymes, while the acceptor compartment consisted of phosphate buffer. Physicochemical characteristics predicted in silico indicated that eremantholide C has a low solubility and high permeability. In-vitro data of eremantholide C showed low solubility, with values for the dose/solubility ratio (ml): 9448.82, 10 389.61 e 15 000.00 for buffers acetate (pH 4.5), intestinal fluid simulated without enzymes (pH 6.8) and phosphate (pH 7.4), respectively. Also, it showed high permeability, with effective permeability of 30.4 × 10 -6 cm/s, a higher result compared with propranolol hydrochloride (9.23 × 10 -6 cm/s). The high permeability combined with its solubility, pharmacological activity and low toxicity demonstrate the importance of eremantholide C as a potential drug candidate. © 2017 Royal Pharmaceutical Society.

Sequential use of bentonites and solar photocatalysis to treat winery wastewater.

PubMed

Rodríguez, Eva; Márquez, Gracia; Carpintero, Juan Carlos; Beltrán, Fernando J; Alvarez, Pedro

2008-12-24

The sequential use of low-cost adsorbent bentonites and solar photocatalysis to treat winery wastewater has been studied. Three commercial sodium-bentonites (MB-M, MB-G, and MB-P) and one calcium-bentonite (Bengel) were characterized and used in this study. These clay materials were useful to totally remove turbidity (90-100%) and, to a lesser extent, color, polyphenols (PPh), and soluble chemical oxygen demand (CODS) from winery wastewater. Both surface area and cation exchange capacity (CEC) of bentonite had a positive impact on treatment efficiency. The effect of pH on turbidity removal by bentonites was studied in the 3.5-12 pH range. The bentonites were capable of greatly removing turbidity from winery wastewater at pH 3.5-5.5, but removal efficiency decreased with pH increase beyond this range. Settling characteristics (i.e., sludge volume index (SVI) and settling rate) of bentonites were also studied. Best settling properties were observed for bentonite doses around 0.5 g/L. The reuse of bentonite for winery wastewater treatment was found not to be advisable as the turbidity and PPh removal efficiencies decreased with successive uses. The resulting wastewater after bentonite treatment was exposed to solar radiation at oxic conditions in the presence of Fe(III) and Fe(III)/H2O2 catalysts. Significant reductions of COD, total organic carbon (TOC), and PPh were achieved by these solar photocatalytic processes.

Effects of acid rain on grapevines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forsline, P.L.; Musselman, R.C.; Dee, R.J.

1983-01-01

Mature vineyard-growing Concord grapevines were sprayed with simulated acid rain solutions ranging from pH 2.5 to 5.5 both as acute treatments at anthesis and chronically throughout the season in 1980 and 1981. In 1981, 8 additional varieties were also treated with simulated acid rain solutions at pH 2.75 and 3.25. With Concord in 1981, few foliar lesions on leaves were visible at pH 2.75. In contrast, many leaf lesions with decreased fruit soluble solids were observed at pH 2.5 in 1980. The relationship between acid-rain and oxidant stipple, chlorosis, and soluble solids in the absence of acid rain leaf lesionsmore » at pH>2.5 remains unclear. Acute sprays (pH2.75) at anthesis reduced pollen germination in four grape cultivars. However, fruit set was reduced in only one of these. Grape yields were not influenced by acid rain treatments. There was no evidence that acid-rain at ambient pH levels had negative effects on grape production or fruit quality.« less

Solubility behavior and biopharmaceutical classification of novel high-solubility ciprofloxacin and norfloxacin pharmaceutical derivatives.

PubMed

Breda, Susana A; Jimenez-Kairuz, Alvaro F; Manzo, Ruben H; Olivera, María E

2009-04-17

The hydrochlorides of the 1:3 aluminum:norfloxacin and aluminum:ciprofloxacin complexes were characterized according to the Biopharmaceutics Classification System (BCS) premises in comparison with their parent compounds. The pH-solubility profiles of the complexes were experimentally determined at 25 and 37 degrees C in the range of pH 1-8 and compared to that of uncomplexed norfloxacin and ciprofloxacin. Both complexes are clearly more soluble than the antibiotics themselves, even at the lowest solubility pHs. The increase in solubility was ascribed to the species controlling solubility, which were analyzed in the solid phases at equilibrium at selected pHs. Additionally, permeability was set as low, based on data reported in the scientific literature regarding oral bioavailability, intestinal and cell cultures permeabilities and also considering the influence of stoichiometric amounts of aluminum. The complexes fulfill the BCS criterion to be classified as class 3 compounds (high solubility/low permeability). Instead, the active pharmaceutical ingredients (APIs) currently used in solid dosage forms, norfloxacin and ciprofloxacin hydrochloride, proved to be BCS class 4 (low solubility/low permeability). The solubility improvement turns the complexes as potential biowaiver candidates from the scientific point of view and may be a good way for developing more dose-efficient formulations. An immediate release tablet showing very rapid dissolution was obtained. Its dissolution profile was compared to that of the commercial ciprofloxacin hydrochloride tablets allowing to dissolution of the complete dose at a critical pH such as 6.8.

Micro-apparatus for rapid determinations of protein solubilities

NASA Technical Reports Server (NTRS)

Pusey, Marc L.; Munson, Sibyl

1991-01-01

We have developed a column-based micro-technique for rapid determinations of protein solubilities. While retaining a large crystal surface area, the column dead volume has been reduced to equal to or less than 5 micro liters. The technique was tested with tetragonal lysozyme (pH 4.5, 0.1 M acetate, 3.0 percent NaCl, 5-25 C) and column volumes of about 60, 300, and 900 micro liters. Identical solubility data were obtained, indicating that equilibration was obtained even in the smallest columns. In addition, solubility data for Br- and I- salts of lysozyme (pH 4.5, 0.1 M acetate buffer, 0.5 M salt concentrations) were obtained. It appears that the technique can be further miniaturized. The limit in further reducing the crystalline column volume is determined by the minimum solution sample size needed to determine the protein concentration.

Leaching characteristics of selected South African fly ashes: Effect of pH on the release of major and trace species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gitari, W.M.; Fatoba, O.O.; Petrik, L.F.

2009-07-01

Fly ash samples from two South African coal-fired power stations were subjected to different leaching tests under alkaline and acidic conditions in an attempt to assess the effect of pH on the leachability of species from the fly ashes and also assess the potential impact of the fly ashes disposal on groundwater and the receiving environment. To achieve this, German Standard leaching (DIN-S4) and Acid Neutralization Capacity (ANC) tests were employed. Ca, Mg, Na, K and SO{sub 4} were significantly leached into solution under the two leaching conditions with the total amounts in ANC leachates higher than that of DIN-S4.more » This indicates that a large fraction of the soluble salts in unweathered fly ash are easily leached. These species represents the fraction that can be flushed off initially from the surface of ash particles on contacting the ash with water. The amounts of toxic trace elements such as As, Se, Cd, Cr and Pb leached out of the fly ashes when in contact with de-mineralized water (DIN-S4 test) were low and below the Target Water Quality Range (TWQR) of South Africa. This is explained by their low concentrations in the fly ashes and their solubility dependence on the pH of the leaching solution. However the amounts of some minor elements such as B, Mn, Fe, As and Se leached out at lower pH ranging between 10 to 4 (ANC test) were slightly higher than the TWQR, an indication that the pH of the leaching solution plays a significant role on the leaching of species in fly ash. The high concentrations of the toxic elements released from the fly ashes at lower pH gives an indication that the disposal of the fly ash could have adverse effects on the receiving environment if the pH of the solution contacting the ashes is not properly monitored.« less

Effects of gastric pH on oral drug absorption: In vitro assessment using a dissolution/permeation system reflecting the gastric dissolution process.

PubMed

Kataoka, Makoto; Fukahori, Miho; Ikemura, Atsumi; Kubota, Ayaka; Higashino, Haruki; Sakuma, Shinji; Yamashita, Shinji

2016-04-01

The aim of the present study was to evaluate the effects of gastric pH on the oral absorption of poorly water-soluble drugs using an in vitro system. A dissolution/permeation system (D/P system) equipped with a Caco-2 cell monolayer was used as the in vitro system to evaluate oral drug absorption, while a small vessel filled with simulated gastric fluid (SGF) was used to reflect the gastric dissolution phase. After applying drugs in their solid forms to SGF, SGF solution containing a 1/100 clinical dose of each drug was mixed with the apical solution of the D/P system, which was changed to fasted state-simulated intestinal fluid. Dissolved and permeated amounts on applied amount of drugs were then monitored for 2h. Similar experiments were performed using the same drugs, but without the gastric phase. Oral absorption with or without the gastric phase was predicted in humans based on the amount of the drug that permeated in the D/P system, assuming that the system without the gastric phase reflected human absorption with an elevated gastric pH. The dissolved amounts of basic drugs with poor water solubility, namely albendazole, dipyridamole, and ketoconazole, in the apical solution and their permeation across a Caco-2 cell monolayer were significantly enhanced when the gastric dissolution process was reflected due to the physicochemical properties of basic drugs. These amounts resulted in the prediction of higher oral absorption with normal gastric pH than with high gastric pH. On the other hand, when diclofenac sodium, the salt form of an acidic drug, was applied to the D/P system with the gastric phase, its dissolved and permeated amounts were significantly lower than those without the gastric phase. However, the oral absorption of diclofenac was predicted to be complete (96-98%) irrespective of gastric pH because the permeated amounts of diclofenac under both conditions were sufficiently high to achieve complete absorption. These estimations of the effects of gastric pH on the oral absorption of poorly water-soluble drugs were consistent with observations in humans. In conclusion, the D/P system with the gastric phase may be a useful tool for better predicting the oral absorption of poorly water-soluble basic drugs. In addition, the effects of gastric pH on the oral absorption of poorly water-soluble drugs may be evaluated by the D/P system with and without the gastric phase. Copyright © 2016 Elsevier B.V. All rights reserved.

Intrinsic solubility estimation and pH-solubility behavior of cosalane (NSC 658586), an extremely hydrophobic diprotic acid.

PubMed

Venkatesh, S; Li, J; Xu, Y; Vishnuvajjala, R; Anderson, B D

1996-10-01

The selection of cosalane (NSC 658586) by the National Cancer Institute for further development as a potential drug candidate for the treatment of AIDS led to the exploration of the solubility behavior of this extremely hydrophobic drug, which has an intrinsic solubility (S0 approaching 1 ng/ml. This study describes attempts to reliably measure the intrinsic solubility of cosalane and examine its pH-solubility behavior. S0 was estimated by 5 different strategies: (a) direct determination in an aqueous suspension: (b) facilitated dissolution; (c) estimation from the octanol/water partition coefficient and octanol solubility (d) application of an empirical equation based on melting point and partition coefficient; and (e) estimation from the hydrocarbon solubility and functional group contributions for transfer from hydrocarbon to water. S0 estimates using these five methods varied over a 5 x 107-fold range Method (a) yielded the highest values, two-orders of magnitude greater than those obtained by method (b) (facilitated dissolution. 1.4 +/- 0.5 ng/ml). Method (c) gave a value 20-fold higher while that from method (d) was in fair agreement with that from facilitated dissolution. Method (e) yielded a value several orders-of-magnitude lower than other methods. A molecular dynamics simulation suggests that folded conformations not accounted for by group contributions may reduce cosalane's effective hydrophobicity. Ionic equilibria calculations for this weak diprotic acid suggested a 100-fold increase in solubility per pH unit increase. The pH-solubility profile of cosalane at 25 degrees C agreed closely with theory. These studies highlight the difficulty in determining solubility of very poorly soluble compounds and the possible advantage of the facilitated dissolution method. The diprotic nature of cosalane enabled a solubility enhancement of > 107-fold by simple pH adjustment.

A Novel Soluble Peptide with pH-Responsive Membrane Insertion.

PubMed

Nguyen, Vanessa P; Alves, Daiane S; Scott, Haden L; Davis, Forrest L; Barrera, Francisco N

2015-11-03

Several diseases, such as cancer, are characterized by acidification of the extracellular environment. Acidosis can be employed as a target to specifically direct therapies to the diseased tissue. We have used first principles to design an acidity-triggered rational membrane (ATRAM) peptide with high solubility in solution that is able to interact with lipid membranes in a pH-dependent fashion. Biophysical studies show that the ATRAM peptide binds to the surface of lipid membranes at pH 8.0. However, acidification leads to the peptide inserting into the lipid bilayer as a transmembrane α-helix. The insertion of ATRAM into membranes occurs at a moderately acidic pH (with a pK of 6.5), similar to the extracellular pH found in solid tumors. Studies with human cell lines showed a highly efficient pH-dependent membrane targeting, without causing toxicity. Here we show that it is possible to rationally design a soluble peptide that selectively targets cell membranes in acidic environments.

Functional properties of tropical banded cricket (Gryllodes sigillatus) protein hydrolysates.

PubMed

Hall, Felicia G; Jones, Owen G; O'Haire, Marguerite E; Liceaga, Andrea M

2017-06-01

Recently, the benefits of entomophagy have been widely discussed. Due to western cultures' reluctance, entomophagy practices are leaning more towards incorporating insects into food products. In this study, whole crickets (Gryllodes sigillatus) were hydrolyzed with alcalase at 0.5, 1.5, and 3.0% (w/w) for 30, 60, and 90min. Degree of hydrolysis (DH), amino acid composition, solubility, emulsion and foaming properties were evaluated. Hydrolysis produced peptides with 26-52% DH compared to the control containing no enzyme (5% DH). Protein solubility of hydrolysates improved (p<0.05) over a range of pH's, exhibiting >30% soluble protein at pH 3 and 7 and 50-90% at alkaline pH, compared with the control. Emulsion activity index ranged from 7 to 32m 2 /g, while foamability ranged from 100 to 155% for all hydrolysates. These improved functional properties demonstrate the potential to develop cricket protein hydrolysates as a source of functional alternative protein in food ingredient formulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Molecular characterization of whey protein hydrolysate fractions with ferrous chelating and enhanced iron solubility capabilities.

PubMed

O'Loughlin, Ian B; Kelly, Phil M; Murray, Brian A; FitzGerald, Richard J; Brodkorb, Andre

2015-03-18

The ferrous (Fe2+) chelating capabilities of WPI hydrolysate fractions produced via cascade membrane filtration were investigated, specifically 1 kDa permeate (P) and 30 kDa retentate (R) fractions. The 1 kDa-P possessed a Fe2+ chelating capability at 1 g L(-1) equivalent to 84.4 μM EDTA (for 30 kDa-R the value was 8.7 μM EDTA). Fourier transformed infrared (FTIR) spectroscopy was utilized to investigate the structural characteristics of hydrolysates and molecular interactions with Fe2+. Solid-phase extraction was employed to enrich for chelating activity; the most potent chelating fraction was enriched in histidine and lysine. The solubility of ferrous sulfate solutions (10 mM) over a range of pH values was significantly (P<0.05) improved in dispersions of hydrolysate fraction solutions (10 g protein L(-1)). Total iron solubility was improved by 72% in the presence of the 1 kDa-P fraction following simulated gastrointestinal digestion (SGID) compared to control FeSO4·7H2O solutions.

Shelf life determinants and enzyme activities of pearl millet: a comparison of changes in stored flour of hybrids, CMS lines, inbreds and composites.

PubMed

Goyal, Preeti; Chugh, L K

2017-09-01

Shelf life of pearl millet flour is very short because of rapid development of rancidity. This investigation was carried out in view of generating breeding material for development of low rancid pearl millet hybrids/varieties. Flour of twenty-one genotypes; seven hybrids, seven CMS lines, five inbreds and two composites stored in covered aluminium boxes at 37 °C for 30 days along with respective fresh flour was analysed for shelf life indicators/determinants. Crude fat content and fat acidity (FA) of fresh flour of the genotypes varied from 3.8 to 7.2% and 11 to 75 mg KOH/100 g d.m., respectively. FA in stored flour ranged between 180 and 330 mg KOH/100 g d.m. After storage, magnitude of decrease in pH of water extract of flour of the genotypes varied from 0.15 to 0.44. Activity of peroxidase (POX) varied from 378 to 588 units in control flour and irrespective of the genotypes decreased upon storage. Increase in FA (difference between FA of fresh and stored flour) rather total build up of FA was positively associated with crude fat content (r = 0.440*) indicated comparatively more prominent role of lipolytic enzymes. Chemical changes taking place in water soluble fraction of flour were independent of fat content as no correlation was discerned between fat content and decrease in pH. Among the hybrids, HHB 197 had lowest crude fat content (4.7%), lowest total build up FA (212 mg KOH/100 g d.m.), slowest increase in FA (191 mg KOH/100 g d.m.), least decrease in pH (0.31) of water soluble fraction flour during storage and lowest activity of POX in fresh flour (377 units/g d.m). Among all the tested CMS lines, inbreds and composites, HBL 11 showed pattern of quantitative changes in FA, pH and POX activity similar to the hybrid HHB 197 and was identified a promising inbred for developing low-rancid pearl millet variety or hybrid.

Acid-base buffering of soils in transitional and transitional-accumulative positions of undisturbed southern-taiga landscapes

NASA Astrophysics Data System (ADS)

Rusakova, E. S.; Ishkova, I. V.; Tolpeshta, I. I.; Sokolova, T. A.

2012-05-01

The method of continuous potentiometric titration (CPT) of soil water suspensions was used to evaluate the acid-base buffering of samples from the major genetic horizons of podzolic soils on a slope and soddy gley soils on the adjacent floodplain of a rivulet. In the soils of the slope, the buffering to acid upon titration from the pH of the initial titration point (ITP) to pH 3 in all the horizons was 1.5-2.0 times lower than that in the podzolic soils of the leveled interfluve, which could be due to the active leaching of exchangeable bases and oxalate-soluble aluminum and iron compounds with the later soil flows. In the soddy gley soils, the buffering to acid in the mineral horizons was 2-10 times higher than that in the podzolic soils. A direct dependence of the soil buffering to acid on the total content of exchangeable bases and on the content of oxalate-soluble aluminum compounds was found. A direct dependence of the buffering to basic upon titration from the ITP to pH 10 on the contents of the oxalate-soluble aluminum and organic matter was observed in the mineral horizons of all the studied soils. The soil treatment with Tamm's reagent resulted in the decrease of the buffering to acid in the soddy gley soils of the floodplain, as well as in the decrease of the buffering to basic in the soils on the slopes and in the soddy gley soils. It was also found that the redistribution of the mobile aluminum compounds between the eluvial, transitional, and transitional-accumulative positions in the undisturbed southern taiga landscapes leads to significant spatial differentiation of the acid-base buffering of the mineral soil horizons with a considerable increase in the buffer capacity of the soils within the transitional-accumulative terrain positions.

Bioavailability of elemental iron powders to rats is less than bakery-grade ferrous sulfate and predicted by iron solubility and particle surface area.

PubMed

Swain, James H; Newman, Samuel M; Hunt, Janet R

2003-11-01

Foods are fortified with elemental forms of iron to reduce iron deficiency. However, the nutritional efficacy of current, commercially produced elemental iron powders has not been verified. We determined the bioavailability of six commercial elemental iron powders and examined how physicochemistry influences bioavailability. Relative biological value (RBV) of the iron powders was determined using a hemoglobin repletion/slope ratio method, treating iron-deficient rats with repletion diets fortified with graded quantities of iron powders, bakery-grade ferrous sulfate or no added iron. Iron powders were assessed physicochemically by measuring iron solubility in hydrochloric acid at pH 1.0 and 1.7, surface area by nitrogen gas adsorption and surface microstructure by electron microscopy. Bioavailability from the iron powders, based on absolute iron intake, was significantly less than from FeSO4 (100%; P < 0.05) with the following rank order: Carbonyl (64%; Ferronyl, U.S.) > Electrolytic (54%; A-131, U.S.) > Electrolytic (46%; Electrolytic Iron, India) > H-Reduced (42%; AC-325, U.S.) > Reduced (24%; ATOMET 95SP, Canada) > CO-Reduced (21%; RSI-325, Sweden). Solubility testing of the iron powders resulted in different relative rankings and better RBV predictability with increasing time at pH 1.7 (R2 = 0.65 at 150 min). The prediction was improved with less time and lower pH (R2 = 0.82, pH 1.0 at 30 min). Surface area, ranging from 90 to 370 m2/kg, was also highly predictive of RBV (R2 = 0.80). Bioavailability of iron powders is less than bakery-grade ferrous sulfate and varies up to three times among different commercial forms. Solubility at pH 1.0 and surface area were predictive of iron bioavailability in rats.

[Preparation of coated tablets of glycyrrhetic acid-HP-beta-cyclodextrin tablets for colon-specific release].

PubMed

Cui, Qi-Hua; Cui, Jing-Hao; Zhang, Jin-Jin

2008-10-01

To prepare coated tablets of glycyrrhetinic acid and hydroxypropyl-beta-cyclodextrin (GTA-HP-beta-CYD) inclusion complex tablets for colon-specific release. In order to improve the solubility of GTA, the GTA-HP-beta-CYD inclusion complex was prepared by ultrasonic-lyophilization technique and its formation were characterized by X-ray powder diffraction profiles and infrared spectrometry. The effects of inclusion condition on the inclusion efficiency and stability coefficient of inclusion complex were investigated, respectively. After prepared GTA-HP-beta-CYD tablets by powder direct compression, the pH dependant polymer Eudragit III and/or mixed with Eudragit II were used for further coating materials in fluid-bed coater. The influences of coating weight on the GTA release in different pH conditions were evaluated to establish the method for prepering colon specific delivery tablets with pulsed release properties. The formation of inclusion complexes were proved by X-ray powder diffraction profile and phase solubility curve. The effect of pH value of solvent was played critical role on the preparation of GTA- HP-beta-CYD inclusion complex. And the inclusion efficiency of GTA was 9. 3% and the solubility was increased to 54. 6 times at optimized method. The Eudragit III coated GTA- HP-beta-CYD tablets with coating weight 10% and 16% were showed pH dependant colon specific release profiles with slow release rate. The release profile of tablets coated with the mixture of Eudragit II and Eudragit III (1:2) were indicated typical pH dependant colon specific and pulsed release properties while the coating weight was 17%. The preliminary method for preparation of colon specific release tablets containing glycyrrhetinic acid with improved solubility was established for further in vivo therapeutic experiment.

Treatment of meats with ionising radiations. VIII.—pH, water-binding capacity and proteolysis of irradiated raw beef and pork during storage, and the ATP-ase activity of irradiated rabbit muscle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrie, R. A.; Sharp, J. G.; Bendall, J. R.

1961-11-01

The immediate effects of 5-Mrad ionizing radiation on beef and pork longissimus dorsi muscles were an increase in pH, a decrease in water-holding capacity, in increment in gel-volume for a given pH rise, and in soluble protein, and increased resistance to low- and high-speed homogenization. The indications of cross-binding induced by irradiation were supported by studies of isolated myofibrils from rabbit psoas muscle. Irradiation markedly reduced the syneresis (18 deg , mu = 0.04) and the swelling (0 deg , mu = 0.25) induced by ATP and, to a lesser extent, over-all fibrillar ATP-ase activity (the initial fast phase beingmore » depressed more than the slower second phase of the reaction). On storage (at -20 deg +37 deg pH and water-binding capacity increased generally with increase of temperature. Changes in pH occurred earlier with pork and to a greater extent than with beef. In sterile beef longissimus dorsi (irradiated or unirradiated) there was a decrease in soluble protein during storage for 60-90 days at 37- (indicating denaturation) and lncreases in TCA-soluble nitrogen and tyrosine (indicating proteolysis, which was more marked in unirradiated samples). The absence of soluble hydroxyproline and the presence of clearly marked cross- striations indicated that the autolysis must have involved sarcoplasmic and not fibrillar or connective tissue protein.« less

Correlation of second virial coefficient with solubility for proteins in salt solutions.

PubMed

Mehta, Chirag M; White, Edward T; Litster, James D

2012-01-01

In this work, osmotic second virial coefficients (B(22)) were determined and correlated with the measured solubilities for the proteins, α-amylase, ovalbumin, and lysozyme. The B(22) values and solubilities were determined in similar solution conditions using two salts, sodium chloride and ammonium sulfate in an acidic pH range. An overall decrease in the solubility of the proteins (salting out) was observed at high concentrations of ammonium sulfate and sodium chloride solutions. However, for α-amylase, salting-in behavior was also observed in low concentration sodium chloride solutions. In ammonium sulfate solutions, the B(22) are small and close to zero below 2.4 M. As the ammonium sulfate concentrations were further increased, B(22) values decreased for all systems studied. The effect of sodium chloride on B(22) varies with concentration, solution pH, and the type of protein studied. Theoretical models show a reasonable fit to the experimental derived data of B(22) and solubility. B(22) is also directly proportional to the logarithm of the solubility values for individual proteins in salt solutions, so the log-linear empirical models developed in this work can also be used to rapidly predict solubility and B(22) values for given protein-salt systems. Copyright © 2011 American Institute of Chemical Engineers (AIChE).

Biowaiver or Bioequivalence: Ambiguity in Sildenafil Citrate BCS Classification.

PubMed

Miranda, Claudia; Pérez-Rodríguez, Zenia; Hernández-Armengol, Rosario; Quiñones-García, Yaidel; Betancourt-Purón, Tania; Cabrera-Pérez, Miguel Ángel

2018-05-01

The aim of the present study is to contribute to the scientific characterization of sildenafil citrate according to the Biopharmaceutics Classification System, following the World Health Organization (WHO) guidelines for biowaivers. The solubility and intestinal permeability data of sildenafil citrate were collected from literature; however, the experimental solubility studies are inconclusive and its "high permeability" suggests an API in the borderline of BCS Class I and Class II. The pH-solubility profile was determined using the saturation shake-flask method over the pH range of 1.2-6.8 at a temperature of 37 °C in aqueous media. The intestinal permeability was determined in rat by a closed-loop in situ perfusion method (the Doluisio technique). The solubility of sildenafil citrate is pH-dependent and at pH 6.8 the dose/solubility ratio obtained does not meet the WHO criteria for "high solubility." The high permeability values obtained by in situ intestinal perfusion in rat reinforce the published permeability data for sildenafil citrate. The experimental results obtained and the data available in the literature suggest that sildenafil citrate is clearly a Class II of BCS, according to the current biopharmaceutics classification system and WHO guidance.

The effect of sulfate on aluminum concentrations in natural waters: some stability relations in the system Al2O3-SO3-H2O at 298 K

USGS Publications Warehouse

Nordstrom, D. Kirk

1982-01-01

While gibbsite and kaolinite solubilities usually regulate aluminum concentrations in natural waters, the presence of sulfate can dramatically alter these solubilities under acidic conditions, where other, less soluble minerals can control the aqueous geochemistry of aluminum. The likely candidates include alunogen, Al2(SO4)3 ?? 17H2O, alunite, KAl3(SO4)2(OH)6, jurbanite, Al(SO4)(OH) ?? 5H2O, and basaluminite, Al4(SO4)(OH)10 ?? 5H2O. An examination of literature values shows that the log Ksp = -85.4 for alunite and log Ksp = -117.7 for basaluminite. In this report the log Ksp = -7.0 is estimated for alunogen and log Ksp = -17.8 is estimated for jurbanite. The solubility and stability relations among these four minerals and gibbsite are plotted as a function of pH and sulfate activity at 298 K. Alunogen is stable only at pH values too low for any natural waters (<0) and probably only forms as efflorescences from capillary films. Jurbanite is stable from pH < 0 up to the range of 3-5 depending on sulfate activity. Alunite is stable at higher pH values than jurbanite, up to 4-7 depending on sulfate activity. Above these pH limits gibbsite is the most stable phase. Basaluminite, although kinetically favored to precipitate, is metastable for all values of pH and sulfate activity. These equilibrium calculations predict that both sulfate and aluminum can be immobilized in acid waters by the precipitation of aluminum hydroxysulfate minerals. Considerable evidence supports the conclusion that the formation of insoluble aluminum hydroxy-sulfate minerals may be the cause of sulfate retention in soils and sediments, as suggested by Adams and Rawajfih (1977), instead of adsorption. ?? 1982.

Comparison of soil solution speciation and diffusive gradients in thin-films measurement as an indicator of copper bioavailability to plants.

PubMed

Zhao, Fang-Jie; Rooney, Corinne P; Zhang, Hao; McGrath, Steve P

2006-03-01

The toxicity effect concentrations (10% effective concentration [EC10] and 50% effective concentration [EC50]) of total added Cu derived from barley root elongation and tomato growth assays varied widely among 18 European soils. We investigated whether this variation could be explained by the solubility or speciation of Cu in soil solutions or the diffusive gradients in thin-films (DGT) measurement. Solubility and Cu speciation varied greatly among the soils tested. However, the EC10 and EC50 of soil solution Cu or free Cu2+ activity varied even more widely than those based on the total added Cu, indicating that solubility or soil solution speciation alone could not explain intersoil variation in Cu toxicity. Estimated EC10 and EC50 of free Cu2+ activity correlated closely and negatively with soil pH, indicating a protective effect of H+, which is consistent with the biotic ligand model concept. The DGT measurement was found to narrow the intersoil variation in EC50 considerably and to be a better predictor of plant Cu concentrations than either soil solution Cu or free Cu2+ activity. We conclude that plant bioavailability of Cu in soil depends on Cu speciation, interactions with protective ions (particularly H+), and the resupply from the solid phase, and we conclude that the DGT measurement provides a useful indicator of Cu bioavailability in soil.

The effects of corrective surgery on endothelial biomarkers and anthropometric data in children with congenital heart disease.

PubMed

Chung, Hung-Tao; Chang, Yu-Sheng; Liao, Sui-Ling; Lai, Shen-Hao

2017-04-01

Objective To investigate the influence of surgical correction on biomarkers of endothelial dysfunction in children with congenital heart disease and to evaluate anthropometric data. Methods Children with pulmonary hypertension (PH) or Tetralogy of Fallot (TOF) who were scheduled for corrective surgery were enrolled in this prospective study. Age-matched healthy children were included as controls. Demographic, haemodynamic and cardiac ultrasonography data were collected. Blood samples were taken pre-surgery, 24-48 hours post-surgery and again 3-6 months later. Several biomarkers (protein C, soluble platelet selectin [CD62P], soluble endothelium selectin [CD62E], soluble leukocyte selectin [CD62L], plasma von Willebrand Factor [vWF] atrial natriuretic peptide [ANP], brain natriuretic peptide[(BNP] and insulin-like growth factor-1 [IGF-1]) were measured. Results Sixty-three children (32 with PH, 15 with TOF, and 16 controls) were enrolled. No significant differences between the PH and TOF groups were observed in the expression of biomarkers pre- and post-surgery. IGF-1 levels were closely related to anthropometric data, particularly those children with PH. Expression of IGF-1 and weight/height normalized after corrective surgery. Conclusions No significant endothelial dysfunction was observed in children with PH or TOF before or after corrective surgery. Significant retardation of growth, particularly weight, was found before surgery and may be related to IGF-1 suppression.

Solubility and stability of dalcetrapib in vehicles and biological media.

PubMed

Gross, Günter; Tardio, Joseph; Kuhlmann, Olaf

2012-11-01

Dalcetrapib solubility was determined in aqueous and in non-aqueous vehicles and in biorelevant media. In a pure aqueous environment the solubility was low but could be increased by addition of surfactants or complexing agents. This was also reflected in the solubility seen in simulated gastrointestinal (GI) fluids, with almost no solubility in simulated gastric fluid, but reasonable solubilisation in simulated intestinal fluids containing lecithin and bile salt. Additionally, the stability of dalcetrapib was determined in simulated GI fluids with and without pancreatic lipase. In solutions without lipase, dalcetrapib was slowly hydrolysed, but in the presence of lipase the hydrolysis rate was significantly faster depending on pH and enzyme activity. In biological fluids, dissolved dalcetrapib appeared to behave similarly being rapidly hydrolysed in human intestinal fluids with a half-life below 20s with no degradation observed in human gastric fluids at low pH. The results provide supportive evidence that absorption is higher under fed conditions and indicate lipase inhibitors might interfere with oral absorption of dalcetrapib. Copyright © 2012 Elsevier B.V. All rights reserved.

Physicochemical characterization of a new pineapple hybrid (FLHORAN41 Cv.).

PubMed

Brat, Pierre; Hoang, Lan Nguyen Thi; Soler, Alain; Reynes, Max; Brillouet, Jean-Marc

2004-10-06

The physicochemical characteristics (pH, total and soluble solids, and titratable acidity), sugars, organic acids, carotenoids, anthocyanins, volatile compounds, and cell wall polysaccharides of a new pineapple hybrid (FLHORAN41 cultivar) were measured throughout maturation and compared with the Smooth Cayenne cv. At full maturity, the FLHORAN41 cv. has a higher titratable acidity and soluble solids content than the Smooth Cayenne cv. The golden yellow flesh and red-orange to scarlet shell of ripe FLHORAN41 cv. fruits are due to carotenoid and anthocyanin levels that are, respectively, 2.5 and 1.5 times higher than those of the flesh and shell of the ripe Smooth Cayenne cv., respectively. During maturation of the FLHORAN41 cv., there was an increase in all classes of aroma compounds (mainly terpene hydrocarbons and esters), although their relative proportions were similar in both cultivars at full maturity. Cell wall polysaccharides undergo little change during maturation.

Effect of iodine disinfectant source and water quality parameters on soluble iodine speciation

NASA Technical Reports Server (NTRS)

Silverstein, Joann; Hurst, Charles; Barkley, Robert; Dunham, Andrew

1993-01-01

Investigations of iodine species distribution of various aqueous solutions of iodine disinfectants and water from equilibrated suspensions of triodide and pentaiodide resins were done at the University of Colorado for the Center for Space Environmental Health during 1992 and 1993. Direct measurements of three individual iodine species: I(-), I2 and I3(-), were made. In addition three measures of total titratable iodine species were used. It has been found that I2 and I3(-) solutions produce a significant fraction of the non-disinfecting species iodine I(-), ranging from 50 to 80% of added iodine, respectively, at pH values of approximately 5. Correspondingly, I2 solutions produce more than twice the concentration of disinfecting iodine species per mass iodine dose than I3(-) solutions. Both I(-) and I2 species were found in aqeuous extracts of pentaiodide resin, although no soluble species were detected with triiodide resin.

Chemical composition of biomass generated in the guava tree pruning

PubMed Central

Camarena-Tello, Julio César; Rocha-Guzmán, Nuria Elizabeth; Gallegos-Infante, José Alberto; González-Laredo, Rubén Francisco; Pedraza-Bucio, Fabiola Eugenia; López-Albarrán, Pablo; Herrera-Bucio, Rafael; Rutiaga-Quiñones, José Guadalupe

2015-01-01

Psidium guajava L. (Myrtaceae) is a native plant of Central America and is now widely cultivated in many tropical regions of the world for the fruit production. In Mexico, in the guava orchards common practices to control fruit production are: water stress, defoliation and pruning. In this study, we report the chemical composition of the biomass (branches and leaves) generated in the pruning practices. The results ranged as follows: pH (4.98-5.88), soda solubility (39.01-70.49 %), ash (1.87-8.20 %); potassium and calcium were the major inorganic elements in ash. No heavy metals were detected in the studied samples; total solubility (15.21-46.60 %), Runkel lignin (17.77-35.26 %), holocellulose (26.56 -69.49 %), α-cellulose (15.53-35.36 %), hemicelluloses (11.02-34.12 %), tannins in aqueous extracts (3.81-9.06 %), and tannins in ethanolic extracts (3.42-15.24 %). PMID:26417359

Chemical composition of biomass generated in the guava tree pruning.

PubMed

Camarena-Tello, Julio César; Rocha-Guzmán, Nuria Elizabeth; Gallegos-Infante, José Alberto; González-Laredo, Rubén Francisco; Pedraza-Bucio, Fabiola Eugenia; López-Albarrán, Pablo; Herrera-Bucio, Rafael; Rutiaga-Quiñones, José Guadalupe

2015-01-01

Psidium guajava L. (Myrtaceae) is a native plant of Central America and is now widely cultivated in many tropical regions of the world for the fruit production. In Mexico, in the guava orchards common practices to control fruit production are: water stress, defoliation and pruning. In this study, we report the chemical composition of the biomass (branches and leaves) generated in the pruning practices. The results ranged as follows: pH (4.98-5.88), soda solubility (39.01-70.49 %), ash (1.87-8.20 %); potassium and calcium were the major inorganic elements in ash. No heavy metals were detected in the studied samples; total solubility (15.21-46.60 %), Runkel lignin (17.77-35.26 %), holocellulose (26.56 -69.49 %), α-cellulose (15.53-35.36 %), hemicelluloses (11.02-34.12 %), tannins in aqueous extracts (3.81-9.06 %), and tannins in ethanolic extracts (3.42-15.24 %).

Application of Multivariable Analysis and FTIR-ATR Spectroscopy to the Prediction of Properties in Campeche Honey

PubMed Central

Pat, Lucio; Ali, Bassam; Guerrero, Armando; Córdova, Atl V.; Garduza, José P.

2016-01-01

Attenuated total reflectance-Fourier transform infrared spectrometry and chemometrics model was used for determination of physicochemical properties (pH, redox potential, free acidity, electrical conductivity, moisture, total soluble solids (TSS), ash, and HMF) in honey samples. The reference values of 189 honey samples of different botanical origin were determined using Association Official Analytical Chemists, (AOAC), 1990; Codex Alimentarius, 2001, International Honey Commission, 2002, methods. Multivariate calibration models were built using partial least squares (PLS) for the measurands studied. The developed models were validated using cross-validation and external validation; several statistical parameters were obtained to determine the robustness of the calibration models: (PCs) optimum number of components principal, (SECV) standard error of cross-validation, (R 2 cal) coefficient of determination of cross-validation, (SEP) standard error of validation, and (R 2 val) coefficient of determination for external validation and coefficient of variation (CV). The prediction accuracy for pH, redox potential, electrical conductivity, moisture, TSS, and ash was good, while for free acidity and HMF it was poor. The results demonstrate that attenuated total reflectance-Fourier transform infrared spectrometry is a valuable, rapid, and nondestructive tool for the quantification of physicochemical properties of honey. PMID:28070445

Reductive Dissolution of PuO2(am): The Effect of Fe(II) and Hydroquinone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rai, Dhanpat; Gorby, Yuri A.; Fredrickson, Jim K.

2002-06-01

SYNOPIS-Reducing agents commonly present in geologic environments can increase solubility of PuO2(am), which is otherwise very insoluble, by many orders of magnitude through reduction of Pu(IV) to Pu(III). The reduction reactions involving Fe(II) and hydroquinone, hitherto unquantified under environmental pH values, were found to be relatively fast and controlled the extent of PuO2(am) dissolution: a decrease in redox potential (pe + pH) resulted in concomitant increase in PuO2(am) solubility.

Effect of Storage on the Physico-Chemical and Antioxidant Properties of Strawberry and Kiwi Leathers.

PubMed

Concha-Meyer, Anibal A; D'Ignoti, Valeria; Saez, Barbara; Diaz, Ricardo I; Torres, Carolina A

2016-03-01

Strawberry and kiwi leathers were used to develop a new healthy and preservative-free fruit snack for new markets. Fruit puree was dehydrated at 60 °C for 20 h and subjected to accelerated storage. Soluble solids, titratable acidity, pH, water activity (aw ), total phenolic (TP), antioxidant activity (AOA) and capacity (ORAC), and color change (browning index) were measured in leathers, cooked, and fresh purees. An untrained panel was used to evaluate consumer acceptability. Soluble solids of fresh purees were 11.24 to 13.04 °Brix, whereas pH was 3.46 to 3.39. Leathers presented an aw of 0.59 to 0.67, and a moisture content of 21 kg water/100 kg. BI decreased in both leathers over accelerated storage period. TP and AOA were higher (P ≤ 0.05) in strawberry formulations. ORAC decreased 57% in strawberry and 65% in kiwi leathers when compared to fruit puree. TP and AOA increased in strawberries during storage. Strawberry and Kiwi leathers may be a feasible new, natural, high antioxidant, and healthy snack for the Chilean and other world markets, such as Europe, particularly the strawberry leather, which was preferred by untrained panelists. © 2016 Institute of Food Technologists®

Laboratory and in-situ reductions of soluble phosphorus in swine waste slurries.

PubMed

Burns, R T; Moody, L B; Walker, F R; Raman

2001-11-01

Laboratory and field experiments were conducted using magnesium chloride (MgCl2) to force the precipitation of struvite (MgNH4PO4 x 6H2O) and reduce the concentration of soluble phosphorus (SP) in swine waste. In laboratory experiments, reductions of SP of 76% (572 to 135 mg P l(-1)) were observed in raw swine manure after addition of magnesium chloride (MgCl2) at a rate calculated to provide a 1.6:1 molar ratio of magnesium (Mg) to total phosphorus. Adjusting the pH of the treated manure to pH 9.0 with sodium hydroxide (NaOH) increased SP reduction to 91% (572 to 50 mg P l(-1)). X-ray diffraction of the precipitate recovered from swine waste slurry treated only with MgCl2 confirmed the presence ofstruvite. The molar N:P:Mg ratio of the recovered precipitate was 1:1.95:0.24, suggesting that compounds in addition to struvite were formed. In a field experiment conducted in a swine manure holding pond, a 90% reduction in SP concentration was observed in approximately 140,000 l of swine manure slurry treated before land application with 2,000 l MgCl2 (64% solution) at ambient slurry temperatures ranging from 5 to 10 degrees C.

Associations of cadmium, zinc, and lead in soils from a lead and zinc mining area as studied by single and sequential extractions.

PubMed

Anju, M; Banerjee, D K

2011-05-01

An exploratory study of the area surrounding a historical Pb-Zn mining and smelting area in Zawar, India, detected significant contamination of the terrestrial environment by heavy metals. Soils (n=87) were analyzed for pH, EC, total organic matter (TOM), Pb, Zn, Mn, and Cd levels. The statistical analysis indicated that the frequency distribution of the analyzed parameters for these soils was not normal. The median concentrations of metals in surface soils were: Pb 420.21 μ g/g, Zn 870.25 μ g/g, Mn 696.70 μ g/g, and Cd 2.09 μ g/g. Zn concentrations were significantly correlated with Cd (r=0.867), indicating that levels of Cd are dependent on Zn. However, pH, electrical conductivity and total organic matter were not correlated significantly with Cd, Pb, Zn, and Mn. To assess the potential mobility of Cd, Pb, and Zn in soils, single (EDTA) as well as sequential extraction scheme (modified BCR) were applied to representative (n=23) soil samples. The amount of Cd, Pb, and Zn extracted by EDTA and their total concentrations showed linear positive correlation, which are statistically significant (r values for Cd, Pb, and Zn being 0.901, 0.971, and 0.795, respectively, and P values being <0.001). The correlation coefficients indicate a strong relation between EDTA-extractable metal and total metal. These results appear to justify the use of 'total' metal contents as a useful preliminary indicator of areas where the risks of metal excess or deficiency are high. The EDTA extractability was maximum for Cd followed by Pb and Zn in soils from all the locations. As indicated by single extraction, the apparent mobility and potential bioavailability of metals in soils followed the order: Cd ≥ Pb > > Zn. Soil samples were sequentially extracted (modified BCR) so that solid pools of Cd, Zn, and Pb could be partitioned into four operationally defined fractions viz. acid-soluble, reducible, oxidizable, and residual. Cadmium was present appreciably (39.41%) in the acid-soluble fraction and zinc was predominantly associated (32.42%) with residual fraction. Pb (66.86%) and Zn (30.44%) were present mainly in the reducible fraction. Assuming that the mobility and bioavailability are related to solubility of geochemical forms of metals and decrease in the order of extraction, the apparent mobility and potential metal bioavailability for these contaminated soil samples is Cd > Zn > Pb.

Buffer Effects in the Solubility, Nucleation and Growth of Chicken Egg White Lysozyme

NASA Technical Reports Server (NTRS)

Gibson, Ursula J.

1999-01-01

The growth of protein crystals is important for determination of their three-dimensional structure, which relates to their biochemical functions and to the practical goal of designing pharmaceuticals to modify that function. While many proteins have been successfully crystallized by a variety of methods, there is still limited understanding of the process of nucleation and growth of even the simplest proteins. Chicken egg-white lysozyme (CEWL) is readily crystallized under a variety of conditions, and studies underway at MSFC are designed to elucidate the mechanisms by which the crystals nucleate and grow. We have investigated the effect of buffer choice on the solubility, nucleation and growth of CEWL. CEWL was purified by dialysis against a .05M phosphate buffer and chromatographic separation from contaminants in a sepharose column. Solubility studies were made as a function of buffer concentration for phosphate and formate buffers, and the nucleation and growth of crystals at 10 C was studied as a function of pH for oxalate, succinate, formate, butyrate, carbonate, phosphate and acetate buffer solutions. The solubility data support the conclusion that there is a solubility minimum as a function of buffer concentration for amphiphilic molecules, while no minimum is observed for a phosphate buffer. Nucleation is suppressed at pH greater than pKa for all buffers except phosphate. The aspect ratio of the (110) faces is shown to be a function of crystal size, rather than pH.

Preparation and Properties of Nanoparticles of Calcium Phosphates With Various Ca/P Ratios.

PubMed

Sun, Limin; Chow, Laurence C; Frukhtbeyn, Stanislav A; Bonevich, John E

2010-01-01

This study aimed at preparing and studying the properties of nanoparticles of calcium phosphate (nCaP) with Ca/P ratios ranging from 1.0 to 1.67 using a spray-drying technique. Micro-structural analyses suggested that the nCaPs with Ca/P ratios of 1.67 to 1.33 were nano-sized amorphous calcium phosphate (ACP) containing varying amounts of acid phosphate and carbonate. The nCaP with Ca/P ratio of 1 contained only nano-sized low crystalline dicalcium phosphate (DCP). BET measurements of the nCaPs showed specific surface areas of (12 ± 2 to 50 ± 1) m(2)/g, corresponding to estimated equivalent spherical diameters of (38 to 172) nm. However, dynamic light scattering measurements revealed much larger particles of (380 ± 49 to 768 ± 111) nm, owing to agglomeration of the smaller primary nano particles as revealed by Scanning Electron Microscopy (SEM). Thermodynamic solubility measurements showed that the nCaPs with Ca/P ratio of 1.33 - 1.67 all have similar solubility behavior. The materials were more soluble than the crystalline hydroxyapatite (HA) at pH greater than about 4.7, and more soluble than β-tricalcium phosphate (β-TCP), octacalcium phosphate (OCP) and DCP at pH above 5.5. Their solubility approached that of α-tricalcium phosphate (α-TCP) at about pH 7. These nCaPs, which cannot be readily prepared by other currently available methods for nanoparticle preparation, have potential biomedical applications.

Feather hydrolysate from Streptomyces sampsonii GS 1322: A potential low cost soil amendment.

PubMed

Jain, Richa; Jain, Aakanchha; Rawat, Neha; Nair, Meera; Gumashta, Raghvendra

2016-06-01

Process parameters for obtaining hydrolysate from hen feathers, i.e., initial pH (5.0-9.0) and incubation period (1-6 day), were set and studied, using Streptomyces sampsonii GS 1322 in submerged and solid state conditions. Under submerged conditions, complete hydrolysis of feathers was observed on fifth day [initial pH 8.0, 28 ± 2°C, shaking (150 rpm)] with release of soluble protein (2985 μg ml(-1)) and amino acids (2407 μg ml(-1)). Cell free hydrolysate showed hydrolysis of casein (18 mm), gelatin (26 mm), collagen (31 mm), hemoglobin (23 mm) and Tween 80 (35 mm) while 445 U keratinase activity. Total soluble protein reached 5 mg ml(-1) in solid state conditions. During Pot experimentation using barren agriculture soil the effect of feather hydrolysate on wheat crop were recorded. Significant increase (p<0.01) in wheat seed germination was observed in treated soils as compared to untreated. Treatment significantly increased plant height from 30 to 60 days and 30-90 days (p<0.001). Treated soil showed an increase in total microbial count, proteolytic activity, phosphate solubilizing bacteria and ammonifying bacteria, whereas pathogenic fungi load was reduced. S. sampsonii GS 1322 can be used for bio-processing of poultry wastes yielding feather hydrolysate rich in proteins and amino acids for development of low-cost organic amendment to accelerate wheat crop growth in barren agricultural land. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Erosive and cariogenicity potential of pediatric drugs: study of physicochemical parameters

PubMed Central

2013-01-01

Background Pediatric medications may possess a high erosive potential to dental tissues due to the existence of acid components in their formulations. The purpose was to determine the erosive and cariogenic potential of pediatric oral liquid medications through the analysis of their physicochemical properties in vitro. Methods A total of 59 substances were selected from the drug reference list of the National Health Surveillance Agency (ANVISA), which belong to 11 therapeutic classes, as follows: analgesics, non-steroidal anti-inflammatory, corticosteroids, antihistamines, antitussives, bronchodilators, antibacterials, antiparasitics, antiemetics, anticonvulsants and antipsychotics. Measurement of pH was performed by potentiometry, using a digital pH meter. For the Total Titratable Acidity (TTA) chemical assay, a 0.1 N NaOH standard solution was used, which was titrated until drug pH was neutralized. The Total Soluble Solids Contents (TSSC) quantification was carried out by refractometry using Brix scale and the analysis of Total Sugar Content was performed according to Fehling’s method. In addition, it was analyzed the information contained in the drug inserts with regard to the presence of sucrose and type of acid and sweetener added to the formulations. Results All drug classes showed acidic pH, and the lowest mean was found for antipsychotics (2.61 ± 0.08). There was a large variation in the TTA (0.1% - 1.18%) and SST (10.44% - 57.08%) values. High total sugar contents were identified in the antitussives (53.25%) and anticonvulsants (51.75%). As described in the drug inserts, sucrose was added in 47.5% of the formulations, as well as citric acid (39.0%), sodium saccharin (36.4%) and sorbitol (34.8%). Conclusion The drugs analyzed herein showed physicochemical characteristics indicative of a cariogenic and erosive potential on dental tissues. Competent bodies’ strategies should be implemented in order to broaden the knowledge of health professionals, drug manufacturers and general consuming public about the risks from the consumption of medicines potentially harmful to dental tissues. PMID:24325544

Erosive and cariogenicity potential of pediatric drugs: study of physicochemical parameters.

PubMed

Xavier, Alidianne Fábia C; Moura, Eline F F; Azevedo, Waldeneide F; Vieira, Fernando F; Abreu, Mauro H N G; Cavalcanti, Alessandro L

2013-12-10

Pediatric medications may possess a high erosive potential to dental tissues due to the existence of acid components in their formulations. The purpose was to determine the erosive and cariogenic potential of pediatric oral liquid medications through the analysis of their physicochemical properties in vitro. A total of 59 substances were selected from the drug reference list of the National Health Surveillance Agency (ANVISA), which belong to 11 therapeutic classes, as follows: analgesics, non-steroidal anti-inflammatory, corticosteroids, antihistamines, antitussives, bronchodilators, antibacterials, antiparasitics, antiemetics, anticonvulsants and antipsychotics. Measurement of pH was performed by potentiometry, using a digital pH meter. For the Total Titratable Acidity (TTA) chemical assay, a 0.1 N NaOH standard solution was used, which was titrated until drug pH was neutralized. The Total Soluble Solids Contents (TSSC) quantification was carried out by refractometry using Brix scale and the analysis of Total Sugar Content was performed according to Fehling's method. In addition, it was analyzed the information contained in the drug inserts with regard to the presence of sucrose and type of acid and sweetener added to the formulations. All drug classes showed acidic pH, and the lowest mean was found for antipsychotics (2.61 ± 0.08). There was a large variation in the TTA (0.1% - 1.18%) and SST (10.44% - 57.08%) values. High total sugar contents were identified in the antitussives (53.25%) and anticonvulsants (51.75%). As described in the drug inserts, sucrose was added in 47.5% of the formulations, as well as citric acid (39.0%), sodium saccharin (36.4%) and sorbitol (34.8%). The drugs analyzed herein showed physicochemical characteristics indicative of a cariogenic and erosive potential on dental tissues. Competent bodies' strategies should be implemented in order to broaden the knowledge of health professionals, drug manufacturers and general consuming public about the risks from the consumption of medicines potentially harmful to dental tissues.

Isolation, Solubility, and Characterization of D-Mannitol Esters of 4-Methoxybenzeneboronic Acid.

PubMed

Lopalco, Antonio; Marinaro, William A; Day, Victor W; Stella, Valentino J

2017-02-01

The purpose of this study was to determine the aqueous solubility of a model phenyl boronic acid, 4-methoxybenzeneboronic acid, as a function of pH both in the absence and in the presence of varying D-mannitol concentration. Solid isolated D-mannitol esters were characterized by differential scanning calorimetry, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray studies, and the boronic acid-to-D-mannitol ratio was quantified by HPLC. Hydrolysis of the monoester was studied using UV spectral differences between the monoester and the parent boronic acid. Two D-mannitol esters of 4-methoxybenzeneboronic acid were isolated. The triboronate ester was very insoluble whereas a symmetrical monoboronate monohydrate was also less soluble than the parent. Both esters were crystalline. The monoboronate monohydrate was, however, more soluble than the parent at alkaline pH values due to its lower pKa value (6.53) compared to the parent acid (9.41). Hydrolysis of the monoboronate was extremely fast when even small amount of water was added to dry acetonitrile solutions of the ester. The hydrolysis was buffer concentration dependent and apparent pH sensitive with hydrolysis accelerated by acid. Implications affecting the formulation of future boronic acid drugs are discussed. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

A water-soluble and water-coordinated Mn(II) complex: synthesis, characterization and phantom MRI image study.

PubMed

Phukan, Bedika; Patel, Anant B; Mukherjee, Chandan

2015-08-07

Ligand H4bedik was reacted with MnCl2·4H2O at pH ∼ 6.5 to give a highly water-soluble and water-coordinated Mn(ii) complex (). The complex was found to show r1 = 3.11 mM(-1) s(-1) per Mn(ii) at 1.4 T and 6.26 mM(-1) s(-1) per Mn(ii) at 14.1 T at 25 °C, pH = 7.4. In addition to r1, the r2 at 14.1 T was found to be 132.78 mM(-1) s(-1) per Mn(ii) at 25 °C, pH = 7.4.

Monitoring the kinetics of the pH driven transition of the anthrax toxin prepore to the pore by biolayer interferometry and surface plasmon resonance

PubMed Central

Naik, Subhashchandra; Brock, Susan; Akkaladevi, Narahari; Tally, Jon; Mcginn-Straub, Wesley; Zhang, Na; Gao, Phillip; Gogol, E. P.; Pentelute, B. L.; Collier, R. John; Fisher, Mark T.

2013-01-01

Domain 2 of the anthrax protective antigen (PA) prepore heptamer unfolds and refolds during endosome acidification to generate an extended 100 Å beta barrel pore that inserts into the endosomal membrane. The PA pore facilitates the pH dependent unfolding and translocation of bound toxin enzymic components, lethal factor (LF) and/or edema factor (EF), from the endosome into the cytoplasm. We constructed immobilized complexes of the prepore with the PA-binding domain of LF (LFN) to monitor the real-time prepore to pore kinetic transition using surface plasmon resonance (SPR) and bio-layer interferometry (BLI). The kinetics of this transition increased as the solution pH was decreased from pH 7.5 to pH 5.0, mirroring acidification of the endosome. Once transitioned, the LFN-PA pore complex was removed from the BLI biosensor tip and deposited onto EM grids, where the PA pore formation was confirmed by negative stain electron microscopy. When the soluble receptor domain (ANTRX2/CMG2) binds the immobilized PA prepore, the transition to the pore state was observed only after the pH was lowered to early or late endosomal pH conditions (5.5 to 5.0 respectively). Once the pore formed, the soluble receptor readily dissociated from the PA pore. Separate binding experiments with immobilized PA pores and soluble receptor indicate that the receptor has a weakened propensity to bind to the transitioned pore. This immobilized anthrax toxin platform can be used to identify or validate potential antimicrobial lead compounds capable of regulating and/or inhibiting anthrax toxin complex formation or pore transitions. PMID:23964683

pH-adjustment strategy for volatile fatty acid production from high-strength wastewater for biological nutrient removal.

PubMed

Xie, Li; Liu, Hui; Chen, Yin-Guang; Zhou, Qi

2014-01-01

Volatile fatty acid (VFA) production from three types of high-strength organic wastewater (cassava thin stillage, starch wastewater and yellow-wine processing wastewater) were compared. The results showed that cassava thin stillage was the most suitable substrate, based on its high specific VFA production (0.68 g chemical oxygen demand (COD)/g initial soluble chemical oxygen demand (SCOD)) and yield (0.72 g COD/g SCOD) as well as low nutrient content in the substrate and fermented liquid. The acid fermented cassava thin stillage was evaluated and compared with sodium acetate in a sequencing batch reactor system. Total nitrogen removal efficiency was higher with fermented cassava thin stillage than with the sodium acetate. The effects of pH and a pH-adjustment strategy on VFA production and composition were determined using cassava thin stillage. At an initial pH range of 7-11, a relatively high VFA concentration of about 9 g COD/L was obtained. The specific VFA production (g COD/g initial SCOD) increased from 0.27 to 0.47 to 0.67 at pH 8 and from 0.26 to 0.68 to 0.81 at pH 9 (initial pH, interval pH, and constant pH adjustment, respectively). The dominant VFA species changed significantly with the increasing frequency of the pH adjustment. Further studies will examine the metabolic pathways responsible for VFA composition.

Studies on physico-chemical changes during artificial ripening of banana (Musa sp) variety 'Robusta'.

PubMed

Kulkarni, Shyamrao Gururao; Kudachikar, V B; Keshava Prakash, M N

2011-12-01

Banana (Musa sp var 'Robusta') fruits harvested at 75-80% maturity were dip treated with different concentrations of ethrel (250-1,000 ppm) solution for 5 min. Ethrel at 500 ppm induced uniform ripening without impairing taste and flavour of banana. Untreated control banana fruits remained shriveled, green and failed to ripen evenly even after 8 days of storage. Fruits treated with 500 ppm of ethrel ripened well in 6 days at 20 ± 1 °C. Changes in total soluble solids, acidity, total sugars and total carotenoids showed increasing trends up to 6 days during ripening whereas fruit shear force values, pulp pH and total chlorophyll in peel showed decreasing trends. Sensory quality of ethrel treated banana fruits (fully ripe) were excellent with respect to external colour, taste, flavour and overall quality.

A Monomeric Membrane Peptide that Lives in Three Worlds: In Solution, Attached to, and Inserted across Lipid Bilayers

PubMed Central

Reshetnyak, Yana K.; Segala, Michael; Andreev, Oleg A.; Engelman, Donald M.

2007-01-01

The membrane peptide pH (low) insertion peptide (pHLIP) lives in three worlds, being soluble in aqueous solution at pH 7.4, binding to the surface of lipid bilayers, and inserting as a transbilayer helix at low pH. With low pH driving the process, pHLIP can translocate cargo molecules attached to its C-terminus via a disulfide and release them in the cytoplasm of a cell. Here we examine a key aspect of the mechanism, showing that pHLIP is monomeric in each of its three major states: soluble in water near neutral pH (state I), bound to the surface of a membrane near neutral pH (state II), and inserted across the membrane as an α-helix at low pH (state III). The peptide does not induce fusion or membrane leakage. The unique properties of pHLIP made it attractive for the biophysical investigation of membrane protein folding in vitro and for the development of a novel class of delivery peptides for the transport of therapeutic and diagnostic agents to acidic tissue sites associated with various pathological processes in vivo. PMID:17557792

Formulation and Pharmacokinetic Evaluation of Polymeric Dispersions Containing Valsartan.

PubMed

Chella, Naveen; Daravath, Bhaskar; Kumar, Dinesh; Tadikonda, Rama Rao

2016-10-01

Valsartan exhibits poor aqueous solubility and dissolution rate limited absorption. The lower solubility in the upper part of gastrointestinal tract (pH-dependant solubility) where its absorption window exists further contributes to the low oral bioavailability of valsartan. The present work was aimed to improve the in vivo pharmacokinetics of valsartan by preparing amorphous polymeric dispersions using Eudragit E 100 as carrier. Eudragit E 100 is a cationic polymer soluble in gastric fluid up to pH 5.0 and exhibits pH-dependent release. Hence, the dispersions prepared using Eudragit E 100 rapidly dissolves at lower pH presenting drug in molecularly dispersed and soluble form at its absorption site. Polymeric solid dispersions were prepared in different drug-to-carrier ratios. The prepared dispersions were evaluated for drug-carrier interactions, solid-state transitions and drug-release properties with the help of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and in vitro dissolution studies. The optimized formulation containing valsartan was tested in rats for bioavailability and pharmacokinetic parameters and compared with that of valsartan pure drug. The results from FTIR studies indicated no interactions between drug and excipients. DSC studies confirmed reduction in crystallinity of drug. The dissolution studies performed in 0.1 N HCl showed significant improvement (p < 0.05) in the dissolution of valsartan. In vivo pharmacokinetic studies showed 199 % relative bioavailability with significant improvement (p < 0.05) in area under the curve compared to valsartan pure drug. Eudragit E 100 can be used to improve the dissolution of drugs that show low solubility at lower pH and thereby enhancing the bioavailability.

Trivalent chromium solubility and its influence on quantification of hexavalent chromium in ambient particulate matter using EPA method 6800.

PubMed

Huang, Lihui; Yu, Chang Ho; Hopke, Philip K; Shin, Jin Young; Fan, Zhihua

2014-12-01

Measurement of carcinogenic Cr(VI) in ambient PM is challenging due to potential errors associated with conversion between Cr (VI) (a carcinogen) and Cr(III) (an essential nutrient). Cr(III) conversion is a particular concern due to its > 80% atomic abundance in total Cr. US. Environmental Protection Agency (EPA) method 6800 that uses water-soluble isotope spikes can be used to correct the interconversion. However, whether the enriched Cr(III) isotope spikes can adequately mimic the Cr(III) species originally in ambient PM is unknown. This study examined the water solubility of Cr(III) in ambient PM and discussed its influence on Cr(VI) measurement. Ambient PM10 samples were collected on Teflon filters at four sites in New Jersey that may have different Cr emission sources. The samples were ultrasonically extracted with 5 mL DI-H2O (pH 5.7) at room temperature for 40 min, and then analyzed by ion chromatography-inductively coupled plasma mass spectrometry (IC-ICPMS). Cr(III) was below detection limit (0.06 ng/m3) for all samples, suggesting water-soluble Cr(III) species, such as CrCl3, Cr(NO3)3, and amorphous Cr(OH)3, in the ambient PM were negligible. Therefore, the enriched 50Cr(III) isotope spike (in the form of Cr(NO3)3) could not mimic the original ambient Cr(III). Only the conversion of 53Cr(VI) (in the form of K2CrO4) was taken into account when correcting the interconversion. We then used NaHCO3-pretreated MCE filters (prespiked with enriched isotope species) to measure Cr(VI) in the ambient PM10. The samples were ultrasonically extracted at 60 C pH 9 solutions for 40 min followed by IC-ICPMS analysis. Due to the correction of Cr(VI) reduction, the Cr(VI) concentrations determined by EPA method 6800, 0.26 ± 0.16 (summer) and 0.16 ± 0.11(winter) ng/m3 (n = 64), were significantly greater than those by the external standard curve, 0.21 ± 0.17 (summer) and 0.10 ± 0.07 (winter) ng/m3 (n = 56) (p < 0.01, Student's t-test). Our study revealed that appropriate application of EPA method 6800 is important because it only applies to soluble fraction of Cr species in ambient PM. Implications: Accurate measurement of carcinogenic Cr(VI) in ambient PM is challenging due to conversion between Cr(VI) (a human carcinogen) and Cr(III) (a human essential nutrient). The conversion of CR(III) is of particular concern due to its dominant presence in total Cr (>80%). This study examined the water solubility of Cr(III) in ambient PM that was collected at four locations in New Jersey. Then we discussed the influence of Cr(III) solubility on the application of EPA method 6800, which utilizes enriched isotope spikes to correct the interconversion. Our results suggested that appropriate application of EPA method 6800 is important because it only applies to soluble fraction of Cr species.

Expression of characteristics of ammonium nutrition as affected by pH of the root medium

NASA Technical Reports Server (NTRS)

Chaillou, S.; Vessey, J. K.; Morot-Gaudry, J. F.; Raper, C. D. Jr; Henry, L. T.; Boutin, J. P.

1991-01-01

To study the effect of root-zone pH on characteristic responses of NH4+ -fed plants, soybeans (Glycine max inverted question markL. inverted question mark Merr. cv. Ransom) were grown in flowing solution culture for 21 d on four sources of N (1.0 mol m-3 NO3-, 0.67 mol m-3 NO3- plus 0.33 mol m-3 NH4+, 0.33 mol m-3 NO3- plus 0.67 mol m-3 NH4+, and 1.0 mol m-3 NH4+) with nutrient solutions maintained at pH 6.0, 5.5, 5.0, and 4.5. Amino acid concentration increased in plants grown with NH4+ as the sole source of N at all pH levels. Total amino acid concentration in the roots of NH4+ -fed plants was 8 to 10 times higher than in NO3(-)-fed plants, with asparagine accounting for more than 70% of the total in the roots of these plants. The concentration of soluble carbohydrates in the leaves of NH4+ -fed plants was greater than that of NO3(-)-fed plants, but was lower in roots of NH4+ -fed plants, regardless of pH. Starch concentration was only slightly affected by N source or root-zone pH. At all levels of pH tested, organic acid concentration in leaves was much lower when NH4+ was the sole N source than when all or part of the N was supplied as NO3-. Plants grown with mixed NO3- plus NH4+ N sources were generally intermediate between NO3(-)- and NH4+ -fed plants. Thus, changes in tissue composition characteristic of NH4+ nutrition when root-zone pH was maintained at 4.5 and growth was reduced, still occurred when pH was maintained at 5.0 or above, where growth was not affected. The changes were slightly greater at pH 4.5 than at higher pH levels.

Methods development for total organic carbon accountability

NASA Technical Reports Server (NTRS)

Benson, Brian L.; Kilgore, Melvin V., Jr.

1991-01-01

This report describes the efforts completed during the contract period beginning November 1, 1990 and ending April 30, 1991. Samples of product hygiene and potable water from WRT 3A were supplied by NASA/MSFC prior to contract award on July 24, 1990. Humidity condensate samples were supplied on August 3, 1990. During the course of this contract chemical analyses were performed on these samples to qualitatively determine specific components comprising, the measured organic carbon concentration. In addition, these samples and known standard solutions were used to identify and develop methodology useful to future comprehensive characterization of similar samples. Standard analyses including pH, conductivity, and total organic carbon (TOC) were conducted. Colorimetric and enzyme linked assays for total protein, bile acid, B-hydroxybutyric acid, methylene blue active substances (MBAS), urea nitrogen, ammonia, and glucose were also performed. Gas chromatographic procedures for non-volatile fatty acids and EPA priority pollutants were also performed. Liquid chromatography was used to screen for non-volatile, water soluble compounds not amenable to GC techniques. Methods development efforts were initiated to separate and quantitate certain chemical classes not classically analyzed in water and wastewater samples. These included carbohydrates, organic acids, and amino acids. Finally, efforts were initiated to identify useful concentration techniques to enhance detection limits and recovery of non-volatile, water soluble compounds.

Kinetics and Products of Chromium(VI) Reduction by Iron(II/III)-Bearing Clay Minerals.

PubMed

Joe-Wong, Claresta; Brown, Gordon E; Maher, Kate

2017-09-05

Hexavalent chromium is a water-soluble pollutant, the mobility of which can be controlled by reduction of Cr(VI) to less soluble, environmentally benign Cr(III). Iron(II/III)-bearing clay minerals are widespread potential reductants of Cr(VI), but the kinetics and pathways of Cr(VI) reduction by such clay minerals are poorly understood. We reacted aqueous Cr(VI) with two abiotically reduced clay minerals: an Fe-poor montmorillonite and an Fe-rich nontronite. The effects of ionic strength, pH, total Fe content, and the fraction of reduced structural Fe(II) [Fe(II)/Fe(total)] were examined. The last variable had the largest effect on Cr(VI) reduction kinetics: for both clay minerals, the rate constant of Cr(VI) reduction varies by more than 3 orders of magnitude with Fe(II)/Fe(total) and is described by a linear free energy relationship. Under all conditions examined, Cr and Fe K-edge X-ray absorption near-edge structure spectra show that the main Cr-bearing product is a Cr(III)-hydroxide and that Fe remains in the clay structure after reacting with Cr(VI). This study helps to quantify our understanding of the kinetics of Cr(VI) reduction by Fe(II/III)-bearing clay minerals and may improve predictions of Cr(VI) behavior in subsurface environments.

Colforsin-induced vasodilation in chronic hypoxic pulmonary hypertension in rats.

PubMed

Yokochi, Ayumu; Itoh, Hiroo; Maruyama, Junko; Zhang, Erquan; Jiang, Baohua; Mitani, Yoshihide; Hamada, Chikuma; Maruyama, Kazuo

2010-06-01

Colforsin, a water-soluble forskolin derivative, directly activates adenylate cyclase and thereby increases the 3',5'-cyclic adenosine monophosphate (cAMP) level in vascular smooth muscle cells. In this study, we investigated the vasodilatory action of colforsin on structurally remodeled pulmonary arteries from rats with pulmonary hypertension (PH). A total of 32 rats were subjected to hypobaric hypoxia (380 mmHg, 10% oxygen) for 10 days to induce chronic hypoxic PH, while 39 rats were kept in room air. Changes in isometric force were recorded in endothelium-intact (+E) and -denuded (-E) pulmonary arteries from the PH and control (non-PH) rats. Colforsin-induced vasodilation was impaired in both +E and -E arteries from PH rats compared with their respective controls. Endothelial removal did not influence colforsin-induced vasodilation in the arteries from control rats, but attenuated it in arteries from PH rats. The inhibition of nitric oxide (NO) synthase did not influence colforsin-induced vasodilation in +E arteries from controls, but attenuated it in +E arteries from PH rats, shifting its concentration-response curve closer to that of -E arteries from PH rats. Vasodilation induced by 8-bromo-cAMP (a cell-permeable cAMP analog) was also impaired in -E arteries from PH rats, but not in +E arteries from PH rats, compared with their respective controls. cAMP-mediated vasodilatory responses without beta-adrenergic receptor activation are impaired in structurally remodeled pulmonary arteries from PH rats. In these arteries, endothelial cells presumably play a compensatory role against the impaired cAMP-mediated vasodilatory response by releasing NO (and thereby attenuating the impairment). The results suggest that colforsin could be effective in the treatment of PH.

Demonstration of in situ product recovery of butyric acid via CO2 -facilitated pH swings and medium development in two-phase partitioning bioreactors.

PubMed

Peterson, Eric C; Daugulis, Andrew J

2014-03-01

Production of organic acids in solid-liquid two-phase partitioning bioreactors (TPPBs) is challenging, and highly pH-dependent, as cell growth occurs near neutral pH, while acid sorption occurs only at low pH conditions. CO2 sparging was used to achieve acidic pH swings, facilitating undissociated organic acid uptake without generating osmotic stress inherent in traditional acid/base pH control. A modified cultivation medium was formulated to permit greater pH reduction by CO2 sparging (pH 4.8) compared to typical media (pH 5.3), while still possessing adequate nutrients for extensive cell growth. In situ product recovery (ISPR) of butyric acid (pKa = 4.8) produced by Clostridium tyrobutyricum was achieved through intermittent CO2 sparging while recycling reactor contents through a column packed with absorptive polymer Hytrel® 3078. This polymer was selected on the basis of its composition as a polyether copolymer, and the use of solubility parameters for predicting solute polymer affinity, and was found to have a partition coefficient for butyric acid of 3. Total polymeric extraction of 3.2 g butyric acid with no CO2 mediated pH swings was increased to 4.5 g via CO2 -facilitated pH shifting, despite the buffering capacity of butyric acid, which resists pH shifting. This work shows that CO2 -mediated pH swings have an observable positive effect on organic acid extraction, with improvements well over 150% under optimal conditions in early stage fermentation compared to CO2 -free controls, and this technique can be applied other organic acid fermentations to achieve or improve ISPR. © 2013 Wiley Periodicals, Inc.

In vitro degradation of multisubstituted hydroxyapatite and fluorapatite in the physiological condition

NASA Astrophysics Data System (ADS)

Sumathi, Shanmugam; Gopal, Buvaneswari

2015-07-01

Structure of hydroxyapatite (HAP) is more flexible towards ionic substitutions. Properties such as solubility, antimicrobial property can be tailored by substitutions. Substituted hydroxyapatite and fluorapatite of formulae BiNaCa3(PO4)3OH, Bi0.5M0.5Ca4(PO4)3OH (M=K, Ag), Ca10-xCux(PO4)6(OH/F)2 d(x=0.05-0.25) and Bi0.5Na0.5Ca4(PO4)3F were synthesized and characterized by powder XRD, FT-IR, SEM-EDAX and TGA. In vitro solubility of the synthesized compounds was studied in the phosphate buffered medium of pH 7.4 at 37 °C. Based on the release of calcium and phosphorus ion concentration and pH, the solubility of these compounds is discussed. Bismuth and sodium co-substituted hydroxyapatite are found to be more soluble compared with other substituted apatite compounds and unsubstituted hydroxyapatite.

Evaluation of Solubility and Microleakage of Glass Carbomer Sealant.

PubMed

Subramaniam, P; Girish Babu, K L; Jayasurya, S

2015-01-01

This study was carried out to evaluate and compare solubility and microleakage of the newly introduced moisture tolerant glass carbomer sealant. For evaluation of solubility, 20 specimens of glass carbomer and conventional glass ionomer were prepared and immersed in artificial saliva of pH 4 and 6 for seven days. The difference between initial and final weight was calculated. For evaluation of microleakage, glass carbomer was compared with a conventional resin sealant. 20 premolar teeth indicated for orthodontic extraction were collected and divided into two groups and the respective sealants were applied. It was subjected to thermocycling and then kept immersed in methylene blue for 24 hours. Dye penetration was scored. The glass carbomer specimens were less soluble than the conventional glass ionomer at both pH values. There was no significant difference in the microleakage. Being moisture resistant, glass carbomer can be used as an alternative fissure sealant material; especially in young children with partially erupted teeth and where obtaining moisture control is difficult.

Effects of Manufacturing Methods on Dissolution and Absorption of Ketoconazole in the Presence of Organic Acid as a pH Modifier.

PubMed

Adachi, Masashi; Hinatsu, Yuta; Kusamori, Kosuke; Katsumi, Hidemasa; Sakane, Toshiyasu; Nakatani, Manabu; Wada, Koichi; Yamamoto, Akira

2017-05-01

Poorly water-soluble compounds have a potential risk of low and variable bioavailability caused by incomplete dissolution. Incorporation of organic acids as pH modifiers is effective method for solubility enhancement of basic compounds and requires no special technique and equipment. The purpose of this study was to evaluate the effect of manufacturing method on the extent of drug solubility enhancement. We successfully prepared the granules and tablets containing ketoconazole (KZ), which is weakly basic, as a model compound and citric acid as a pH modifier using conventional wet and dry granulations. KZ solubility under non-sink condition was enhanced with supersaturation using both wet and dry granulations. High-shear granulation was the most effective method in terms of KZ dissolution enhancement, because both an intimate contact and strong bonding between KZ and incorporated acid were achieved. KZ dissolved amount from the granules prepared by high-shear granulation was about eight times higher than that from the granules without the acid. The granulation involved to suppress a diffusion of acid dissolved, leading to the effectively maintained supersaturation state. The bioavailability of KZ after oral administration to rats was improved by applying high-shear granulation with citric acid independent of gastrointestinal pH. The granules prepared by high-shear granulation showed the bioavailability about 1.7-fold higher than that of the physical mixture in rats with and without neutralization of stomach. As a result, both the dissolution and absorption rates of KZ after oral administration were enhanced using conventional manufacturing technology.

Multidentate-Protected Colloidal Gold Nanocrystals: pH Control of Cooperative Precipitation and Surface Layer Shedding

PubMed Central

Kairdolf, Brad A.; Nie, Shuming

2011-01-01

Colloidal gold nanocrystals with broad size tunability and unusual pH-sensitive properties have been synthesized by using multidentate polymer ligands. Containing both carboxylic functional groups and sterically hindered aliphatic chains, the multidentate ligands are able to both reduce gold precursors and to stabilize gold nanoclusters during nucleation and growth. The “as-synthesized” nanocrystals are protected by an inner coordinating layer and an outer polymer layer, and are soluble in water and polar solvents. When the solution pH is lowered by just 0.6 units (from pH 4.85 to 4.25), the particles undergo a dramatic cooperative transition from being soluble to insoluble, allowing rapid isolation, purification, and redispersion of the multidentate-protected nanocrystals. A surprise finding is that when a portion of the surface carboxylate groups is neutralized by protonation, the particles irreversibly shed their outer polymer layer and become soluble in nonpolar organic solvents. Further, the multidentate polymer coatings are permeable to small organic molecules, in contrast to tightly packed self-assembled monolayers of alkanethiols on gold. These insights are important towards the design of “smart” imaging and therapeutic nanoparticles that are activated by small pH changes in the tumor interstitial space or endocytic organelles. PMID:21510704

Effect of pH and the role of organic matter in the adsorption of isoproturon on soils.

PubMed

Ertli, Tímea; Marton, Aurél; Földényi, Rita

2004-11-01

Equilibrium measurements were carried out with the herbicide isoproturon on natural adsorbents (brown forest-, chernozem-, sandy soils and quartz) in different buffered media (pH 5, 7, 8 phosphate buffer). Adsorption isotherms were fitted by a multi-step adsorption equation providing numerical information used in the environmental propagation models and risk assessment works. In the adsorption of the slightly polar isoproturon the dissolved organic matter of the soil and the pH play an important role. At molecular level, results are interpreted by taking into consideration the hydrophobic interaction and the formation of hydrogen bonds between the surface and the solute. The observed adsorption behavior indicates that the organic matter content of the soils and its soluble fulvic acid, alkaline soluble humic acid and insoluble humin fractions were considerable different. The chernozem soil containing the highest amount of insoluble organic fraction proved to be a very efficient adsorbent. The brown forest and the sandy soils exhibit rather similar adsorbent properties but at pH 7 the latter containing more fulvic acid adsorbs less isoproturon due to the enhanced solubility of the soil organic matter. In alkaline conditions the negatively charged solute and the surface repel each other and the hydrophobic interactions are also weaker than in neutral media.

Controlled Aggregation and Increased Stability of β-Glucuronidase by Cellulose Binding Domain Fusion

PubMed Central

Kim, Moonjung; Kwon, Kil Koang; Fu, Yaoyao; Kim, Haseong; Lee, Hyewon; Lee, Dae-Hee; Jung, Heungchae; Lee, Seung-Goo

2017-01-01

Cellulose-binding domains (CBDs) are protein domains with cellulose-binding activity, and some act as leaders in the localization of cellulosomal scaffoldin proteins to the hydrophobic surface of crystalline cellulose. In this study, we found that a CBD fusion enhanced and improved soluble β-glucuronidase (GusA) enzyme properties through the formation of an artificially oligomeric state. First, a soluble CBD fused to the C-terminus of GusA (GusA-CBD) was obtained and characterized. Interestingly, the soluble GusA-CBD showed maximum activity at higher temperatures (65°C) and more acidic pH values (pH 6.0) than free GusA did (60°C and pH 7.5). Moreover, the GusA-CBD enzyme showed higher thermal and pH stabilities than the free GusA enzyme did. Additionally, GusA-CBD showed higher enzymatic activity in the presence of methanol than free GusA did. Evaluation of the protease accessibility of both enzymes revealed that GusA-CBD retained 100% of its activity after 1 h incubation in 0.5 mg/ml protease K, while free GusA completely lost its activity. Simple fusion of CBD as a single domain may be useful for tunable enzyme states to improve enzyme stability in industrial applications. PMID:28099480

Improved sugar beet pectin-stabilized emulsions through complexation with sodium caseinate.

PubMed

Li, Xiangyang; Fang, Yapeng; Phillips, Glyn O; Al-Assaf, Saphwan

2013-02-13

The study investigates the complexes formed between sodium caseinate (SC) and sugar beet pectin (SBP) and to harness them to stabilize SBP emulsions. We find that both hydrophobic and electrostatic interactions are involved in the complexation. In SC/SBP mixed solution, soluble SC/SBP complexes first form on acidification and then aggregate into insoluble complexes, which disassociate into soluble polymers upon further decreasing pH. The critical pH's for the formation of soluble and insoluble complexes and disappearance of insoluble complexes are designated as pH(c), pH(φ), and pH(d), respectively. These critical pH values define four regions in the phase diagram of complexation, and SC/SBP emulsions were prepared in these regions. The results show that the stability of SBP-stabilized emulsion is greatly improved at low SC/SBP ratios and acidic pH's. This enhancement can be attributed to an increase in the amount of adsorbed SBP as a result of cooperative adsorption to sodium caseinate. Using a low ratio of SC/SBP ensured that all caseinate molecules are completely covered by adsorbed SBP chains, which eliminates possible instability induced by thermal aggregation of caseinate molecules resulting from stress acceleration at elevated temperatures. A mechanistic model for the behavior is proposed.

Controlled Aggregation and Increased Stability of β-Glucuronidase by Cellulose Binding Domain Fusion.

PubMed

Yeom, Soo-Jin; Han, Gui Hwan; Kim, Moonjung; Kwon, Kil Koang; Fu, Yaoyao; Kim, Haseong; Lee, Hyewon; Lee, Dae-Hee; Jung, Heungchae; Lee, Seung-Goo

2017-01-01

Cellulose-binding domains (CBDs) are protein domains with cellulose-binding activity, and some act as leaders in the localization of cellulosomal scaffoldin proteins to the hydrophobic surface of crystalline cellulose. In this study, we found that a CBD fusion enhanced and improved soluble β-glucuronidase (GusA) enzyme properties through the formation of an artificially oligomeric state. First, a soluble CBD fused to the C-terminus of GusA (GusA-CBD) was obtained and characterized. Interestingly, the soluble GusA-CBD showed maximum activity at higher temperatures (65°C) and more acidic pH values (pH 6.0) than free GusA did (60°C and pH 7.5). Moreover, the GusA-CBD enzyme showed higher thermal and pH stabilities than the free GusA enzyme did. Additionally, GusA-CBD showed higher enzymatic activity in the presence of methanol than free GusA did. Evaluation of the protease accessibility of both enzymes revealed that GusA-CBD retained 100% of its activity after 1 h incubation in 0.5 mg/ml protease K, while free GusA completely lost its activity. Simple fusion of CBD as a single domain may be useful for tunable enzyme states to improve enzyme stability in industrial applications.

Solubility enhancement of BCS Class II drug by solid phospholipid dispersions: Spray drying versus freeze-drying.

PubMed

Fong, Sophia Yui Kau; Ibisogly, Asiye; Bauer-Brandl, Annette

2015-12-30

The poor aqueous solubility of BCS Class II drugs represents a major challenge for oral dosage form development. Using celecoxib (CXB) as model drug, the current study adopted a novel solid phospholipid nanoparticle (SPLN) approach and compared the effect of two commonly used industrial manufacturing methods, spray- and freeze-drying, on the solubility and dissolution enhancement of CXB. CXB was formulated with Phospholipoid E80 (PL) and trehalose at different CXB:PL:trehalose ratios, of which 1:10:16 was the optimal formulation. Spherical amorphous SPLNs with average diameters <1μm were produced by spray-drying; while amorphous 'matrix'-like structures of solid PL dispersion with larger particle sizes were prepared by freeze-drying. Formulations from both methods significantly enhanced the dissolution rates, apparent solubility, and molecularly dissolved concentration of CXB in phosphate buffer (PBS, pH 6.5) and in biorelevant fasted state simulated intestinal fluid (FaSSIF, pH 6.5) (p<0.05). While similar dissolution rates were found, the spray-dried SPLNs had a larger enhancement in apparent solubility (29- to 132-fold) as well as molecular solubility (18-fold) of CXB at equilibrium (p<0.05). The strong capability of the spray-dried SPLNs to attain 'true' supersaturation state makes them a promising approach for bioavailability enhancement of poorly soluble drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of Dephytinization by Fermentation and Hydrothermal Autoclaving Treatments on the Antioxidant Activity, Dietary Fiber, and Phenolic Content of Oat Bran.

PubMed

Özkaya, H; Özkaya, B; Duman, B; Turksoy, S

2017-07-19

Fermentation and hydrothermal methods were tested to reduce the phytic acid (PA) content of oat bran, and the effects of these methods on the dietary fiber (DF) and total phenolic (TP) contents as well as the antioxidant activity (AA) were also investigated. Fermentation with 6% yeast and for 6 h resulted in 88.2% reduction in PA content, while it only resulted in 32.5% reduction in the sample incubated for 6 h without yeast addition. The PA loss in autoclaved oat bran sample (1.5 h, pH 4.0) was 95.2% while it was 41.8% at most in the sample autoclaved without pH adjustment. In both methods, soluble, insoluble, and total DF contents of samples were remarkably higher than the control samples. Also for TP in the oat bran samples, both processes led to 17% and 39% increases, respectively, while AA values were 8% and 15%, respectively. Among all samples, the autoclaving process resulted in the lowest PA and the greatest amount of bioactive compounds.

Morphological and Chemical Studies of the Spores and Parasporal Bodies of Bacillus laterosporus

PubMed Central

Fitz-James, Philip C.; Young, I. Elizabeth

1958-01-01

Spores of Bacillus laterosporus were studied to determine the chemical and morphological nature of their basophilic canoe-shaped parasporal bodies. An unusually high phosphorus content of these spores compared to other Bacillus species appeared to be associated with the parasporal body. Preparations of these "canoes" still attached to the spore coats were indeed high in phosphorus, but also in nitrogen. They were free of lipide-soluble and nucleic acid phosphorus and stained for protein. Some 50 per cent of the total nitrogen, but only 6 to 10 per cent of the total P were liberated by extraction with alkali-thioglycollate (pH 11.5) or alkali alone (pH 12.2–12.5). Proteinaceous material was recovered from these alkaline extracts and electron microscopy indicated that there had been a marked loss of "canoe" substance. Extraction with acid, removed some 80 per cent of the phosphorus associated with the "canoes" as orthophosphate. Chromatographic analyses for amino acids indicated some 14 ninhydrin-positive spots in the canoe-coat preparations whereas the whole spores contained at least 16. PMID:13587561

Changes in Acidity, TSS, and Sugar Content at Different Storage Periods of the Postharvest Mango (Mangifera indica L.) Influenced by Bavistin DF

PubMed Central

Islam, Md. Khairul; Khan, M. Z. H.; Sarkar, M. A. R.; Absar, Nurul; Sarkar, S. K.

2013-01-01

A detailed study was carried out with the postharvest mangoes (namely, the Langra and the Khirshapat) treated with different levels of Bavistin DF (BDF) solution (namely, 250, 500, and 750 ppm) for obtaining results on biochemical changes as well as storability of postharvest mango. The experiment was laid out in randomized complete block design with three replicates. The results of the experiments exhibited that only the single effect of varieties was found to be significant in most of the parameters studied. The Langra enriched a greater quantity of titratable acidity and total soluble solid (TSS) at 3rd day, over the Khirshapat. On the other hand, Khirshapat showed increased pulp pH and TSS at all the storage duration. The results explored that some physicochemical properties, namely, pulp pH, TSS, sugar (total, reducing, and nonreducing), and titratable acidity along with shelf life drastically decreased from untreated mangoes. Bavistin DF with the doses of 750 ppm showed better results in delaying the changes in physicochemical properties and extended shelf life. PMID:26904616

The allergens of Schistosoma mansoni

PubMed Central

Harris, W. G.

1973-01-01

Ten antigen fractions were prepared from adult Schistosoma mansoni by extraction into borate-buffered saline, precipitation at pH 4.6 and separation on Sephadex G-100. The allergic activity of these antigens was assayed by a modified Prausnitz—Kustner type reaction in rats; this test system was found to be sensitive and consistent, allowing differences in allergenicity between antigens to be accurately assessed. Skin-reactivity was detected in both acid-soluble and acid-insoluble fractions. Specific allergenicity was located in peak 3 of a G-100 separation of the acid-soluble fraction and in peaks 1 and 2 of a G-100 separation of the acid-insoluble fraction suggesting that the allergens of S. mansoni were of at least two types: (1) a protein of mol. wt above 150,000 precipitated at pH 4.6, and (2) a protein of mol. wt 20–30,000 remaining in solution at this pH. It is suggested that both these allergens are glycoproteins. Non-specific histamine-releasing agents were found in peak 1 of the G-100 separation of the acid-soluble material. ImagesFIG. 1 PMID:4122335

Enhancement of bismuth antibacterial activity with lipophilic thiol chelators.

PubMed Central

Domenico, P; Salo, R J; Novick, S G; Schoch, P E; Van Horn, K; Cunha, B A

1997-01-01

The antibacterial properties of bismuth are greatly enhanced when bismuth is combined with certain lipophilic thiol compounds. Antibacterial activity was enhanced from 25- to 300-fold by the following seven different thiols, in order of decreasing synergy: 1,3-propanedithiol, dimercaprol (BAL), dithiothreitol, 3-mercapto-2-butanol, beta-mercaptoethanol, 1-monothioglycerol, and mercaptoethylamine. The dithiols produced the greatest synergy with bismuth at optimum bismuth-thiol molar ratios of from 3:1 to 1:1. The monothiols were generally not as synergistic and required molar ratios of from 1:1 to 1:4 for optimum antibacterial activity. The most-active mono- or dithiols were also the most soluble in butanol. The intensity of the yellow formed by bismuth-thiol complexes reflected the degree of chelation and correlated with antibacterial potency at high molar ratios. The bismuth-BAL compound (BisBAL) was active against most bacteria, as assessed by broth dilution, agar diffusion, and agar dilution analyses. Staphylococci (MIC, 5 to 7 microM Bi3+) and Helicobacter pylori (MIC, 2.2 microM) were among the most sensitive bacteria. Gram-negative bacteria were sensitive (MIC, < 17 microM). Enterococci were relatively resistant (MIC, 63 microM Bi3+). The MIC range for anaerobes was 15 to 100 microM Bi3+, except for Clostridium difficile (MIC, 7.5 microM). Bactericidal activity averaged 29% above the MIC. Bactericidal activity increased with increasing pH and/or increasing temperature. Bismuth-thiol solubility, stability, and antibacterial activity depended on pH and the bismuth-thiol molar ratio. BisBAL was stable but ineffective against Escherichia coli at pH 4. Activity and instability (reactivity) increased with increasing alkalinity. BisBAL was acid soluble at a molar ratio of greater than 3:2 and alkaline soluble at a molar ratio of less than 2:3. In conclusion, certain lipophilic thiol compounds enhanced bismuth antibacterial activity against a broad spectrum of bacteria. The activity, solubility, and stability of BisBAL were strongly dependent on the pH, temperature, and molar ratio. Chelation of bismuth with certain thiol agents enhanced the solubility and lipophilicity of this cationic heavy metal, thereby significantly enhancing its potency and versatility as an antibacterial agent. PMID:9257744

Rapid determination of water- and fat-soluble vitamins with microemulsion electrokinetic chromatography.

PubMed

Yin, Changna; Cao, Yuhua; Ding, Shaodong; Wang, Yun

2008-06-06

A rapid, reliable and reproducible method based on microemulsion electrokinetic chromatography (MEEKC) for simultaneous determination of 13 kinds of water- and fat-soluble vitamins has been developed in this work. A novel microemulsion system consisting of 1.2% (w/w) sodium lauryl sulphate (SDS), 21% (v/v) 1-butanol, 18% (v/v) acetonitrile, 0.8% (w/w) n-hexane, 20mM borax buffer (pH 8.7) was applied to improve selectivity and efficiency, as well as shorten analysis time. The composition of microemulsion used as the MEEKC running buffer was investigated thoroughly to obtain stable separation medium, as well as the optimum determination conditions. Acetonitrile as the organic solvent modifier, pH of the running buffer and 1-butanol as the co-surfactant played the most important roles for the separation of the fat-soluble vitamins, water-soluble vitamins and stabilization of system, respectively. The 13 water- and fat-soluble vitamins were baseline separated within 30 min. The system was applied to determine water- and fat-soluble vitamins in commercial multivitamin pharmaceutical formulation, good accuracy and precision were obtained with recoveries between 97% and 105%, relative standard derivations (RSDs) less than 1.8% except vitamin C, and acceptable quantitative results corresponding to label claim.

Analysis of the pH-Dependent Fe(III) Ion Chelating Activity of Anthocyanin Extracted from Black Soybean [Glycine max (L.) Merr.] Coats.

PubMed

Xie, Yanli; Zhu, Xiaolu; Li, Yuan; Wang, Chen

2018-02-07

The Fe(III) chelating activity of anthocyanin extracted from black soybean coats was investigated at pH 3.0, 5.0, 6.5, 7.0, and 7.4 with fluorescence spectroscopy and microscale thermophoresis (MST). Cyanidin-3-glucoside (C3G) was determined to be 98% of the total anthocyanin by high-performance liquid chromatography. The binding affinity (K a ) exhibited significant pH-dependent behavior: K a was 9.7167 × 10 4 , 1.0837 × 10 4 , 1.4284 × 10 4 , 5.4550 × 10 4 , and 3.0269 × 10 4 M -1 at pH 3.0, 5.0, 6.5, 7.0, and 7.4, respectively (p < 0.05). The MST data showed that ΔG < 0 and ΔH < 0, demonstrating that chelation is spontaneous and exothermic. Because both ΔH and ΔS < 0, the chelation involves hydrogen bonds and/or van der Waals forces for pH 3.0, 5.0, and 6.5. Electrostatic interactions contributed to chelation at pH 7.0 and 7.4 with ΔH < 0 and ΔS > 0. With the formation of chelates, C3G improved the solubility of Fe(III) at pH 6.5, 7.0, and 7.4 to enhance the ferric ion bioavailability, except for aggregation observed at pH 5.0.

Decreased solubilization of Pu(IV) polymers by humic acids under anoxic conditions

NASA Astrophysics Data System (ADS)

Xie, Jinchuan; Lin, Jianfeng; Liang, Wei; Li, Mei; Zhou, Xiaohua

2016-11-01

Pu(IV) polymer has a very low solubility (log[Pu(IV)aq]total = -10.4 at pH 7.2 and I = 0). However, some aspects of their environmental fate remain unclear. Humic acids are able to complex with Pu4+ ions and their dissolved species (<10 kD) in the groundwater (neutral to alkaline pH) may cause solubilization of the polymers. Also, humic acids have the native reducing capacity and potentially reduce the polymeric Pu(IV) to Pu(III)aq (log[Pu(III)aq]total = -5.3 at pH 7.2 and I = 0). Solubilization and reduction of the polymers can enhance their mobility in subsurface environments. Nevertheless, humic acids readily coat the surfaces of metal oxides via electrostatic interaction and ligand exchange mechanisms. The humic coatings are expected to prevent both solubilization and reduction of the polymers. Experiments were conducted under anoxic and slightly alkaline (pH 7.2) conditions in order to study whether humic acids have effects on stability of the polymers. The results show that the polymeric Pu(IV) was almost completely transformed into aqueous Pu(IV) in the presence of EDTA ligands. In contrast, the dissolved humic acids did not solubilize the polymers but in fact decreased their solubility by one order of magnitude. The humic coatings were responsible for the decreased solubilization. Such coatings limited the contact between the polymers and EDTA ligands, especially at the relatively high concentrations of humic acids (>0.57 mg/L). Solubilization of the humic-coated polymers was thus inhibited to a significant extent although EDTA, having the great complexation ability, was present in the humic solutions. Reduction of Pu(IV) polymers by the humic acids was also not observed in the absence of EDTA. In the presence of EDTA, the polymers were partially reduced to Pu(III)aq by the humic acids of 0.57 mg/L and the percentage of Pu(III)aq accounted for 51.7% of the total aqueous Pu. This demonstrates that the humic acids were able to reduce the aqueous Pu(IV), instead of the polymeric Pu(IV). Such a demonstration is supported by the very positive redox potential of aqueous Pu(IV)-EDTA complex: Eho ‧ (PuL24-/PuL25-) = 154.3 mV >>Eh (PuO2 (am) /Pu3+) = -182.7 mV calculated at 10-10 mol/L Pu3+ and pH 7.2. At the higher humic concentrations (>0.57 mg/L), the polymers were reduced to a lesser extent because the much denser humic coatings resulted in lower concentrations of the aqueous Pu(IV). Consequently, humic acids make Pu(IV) polymers pretty stable unless the artificial ligands such as EDTA are present in the groundwater.

Decreasing DOC trends in soil solution along the hillslopes at two IM sites in southern Sweden--geochemical modeling of organic matter solubility during acidification recovery.

PubMed

Löfgren, Stefan; Gustafsson, Jon Petter; Bringmark, Lage

2010-12-01

Numerous studies report increased concentrations of dissolved organic carbon (DOC) during the last two decades in boreal lakes and streams in Europe and North America. Recently, a hypothesis was presented on how various spatial and temporal factors affect the DOC dynamics. It was concluded that declining sulphur deposition and thereby increased DOC solubility, is the most important driver for the long-term DOC concentration trends in surface waters. If this recovery hypothesis is correct, the DOC levels should increase both in the soil solution as well as in the surrounding surface waters as soil pH rises and the ionic strength declines due to the reduced input of SO(4)(2-) ions. In this project a geochemical model was set up to calculate the net humic charge and DOC solubility trends in soils during the period 1996-2007 at two integrated monitoring sites in southern Sweden, showing clear signs of acidification recovery. The Stockholm Humic Model was used to investigate whether the observed DOC solubility is related to the humic charge and to examine how pH and ionic strength influence it. Soil water data from recharge and discharge areas, covering both podzols and riparian soils, were used. The model exercise showed that the increased net charge following the pH increase was in many cases counteracted by a decreased ionic strength, which acted to decrease the net charge and hence the DOC solubility. Thus, the recovery from acidification does not necessarily have to generate increasing DOC trends in soil solution. Depending on changes in pH, ionic strength and soil Al pools, the trends might be positive, negative or indifferent. Due to the high hydraulic connectivity with the streams, the explanations to the DOC trends in surface waters should be searched for in discharge areas and peat lands. Copyright © 2010 Elsevier B.V. All rights reserved.

Uptake of Silicon by Sugarcane from Applied Sources May Not Reflect Plant-Available Soil Silicon and Total Silicon Content of Sources.

PubMed

Keeping, Malcolm G

2017-01-01

Soils of the tropics and sub-tropics are typically acid and depleted of soluble sources of silicon (Si) due to weathering and leaching associated with high rainfall and temperatures. Together with intensive cropping, this leads to marginal or deficient plant Si levels in Si-accumulating crops such as rice and sugarcane. Although such deficiencies can be corrected with exogenous application of Si sources, there is controversy over the effectiveness of sources in relation to their total Si content, and their capacity to raise soil and plant Si concentrations. This study tested the hypothesis that the total Si content and provision of plant-available Si from six sources directly affects subsequent plant Si uptake as reflected in leaf Si concentration. Two trials with potted cane plants were established with the following Si sources as treatments: calcium silicate slag, fused magnesium (thermo) phosphate, volcanic rock dust, magnesium silicate, and granular potassium silicate. Silicon sources were applied at rates intended to achieve equivalent elemental soil Si concentrations; controls were untreated or lime-treated. Analyses were conducted to determine soil and leaf elemental concentrations. Among the sources, calcium silicate produced the highest leaf Si concentrations, yet lower plant-available soil Si concentrations than the thermophosphate. The latter, with slightly higher total Si than the slag, produced substantially greater increases in soil Si than all other products, yet did not significantly raise leaf Si above the controls. All other sources did not significantly increase soil or leaf Si concentrations, despite their high Si content. Hence, the total Si content of sources does not necessarily concur with a product's provision of soluble soil Si and subsequent plant uptake. Furthermore, even where soil pH was raised, plant uptake from thermophosphate was well below expectation, possibly due to its limited liming capacity. The ability of the calcium silicate to provide Si while simultaneously and significantly increasing soil pH, and thereby reducing reaction of Si with exchangeable Al 3+ , is proposed as a potential explanation for the greater Si uptake into the shoot from this source.

Uptake of Silicon by Sugarcane from Applied Sources May Not Reflect Plant-Available Soil Silicon and Total Silicon Content of Sources

PubMed Central

Keeping, Malcolm G.

2017-01-01

Soils of the tropics and sub-tropics are typically acid and depleted of soluble sources of silicon (Si) due to weathering and leaching associated with high rainfall and temperatures. Together with intensive cropping, this leads to marginal or deficient plant Si levels in Si-accumulating crops such as rice and sugarcane. Although such deficiencies can be corrected with exogenous application of Si sources, there is controversy over the effectiveness of sources in relation to their total Si content, and their capacity to raise soil and plant Si concentrations. This study tested the hypothesis that the total Si content and provision of plant-available Si from six sources directly affects subsequent plant Si uptake as reflected in leaf Si concentration. Two trials with potted cane plants were established with the following Si sources as treatments: calcium silicate slag, fused magnesium (thermo) phosphate, volcanic rock dust, magnesium silicate, and granular potassium silicate. Silicon sources were applied at rates intended to achieve equivalent elemental soil Si concentrations; controls were untreated or lime-treated. Analyses were conducted to determine soil and leaf elemental concentrations. Among the sources, calcium silicate produced the highest leaf Si concentrations, yet lower plant-available soil Si concentrations than the thermophosphate. The latter, with slightly higher total Si than the slag, produced substantially greater increases in soil Si than all other products, yet did not significantly raise leaf Si above the controls. All other sources did not significantly increase soil or leaf Si concentrations, despite their high Si content. Hence, the total Si content of sources does not necessarily concur with a product's provision of soluble soil Si and subsequent plant uptake. Furthermore, even where soil pH was raised, plant uptake from thermophosphate was well below expectation, possibly due to its limited liming capacity. The ability of the calcium silicate to provide Si while simultaneously and significantly increasing soil pH, and thereby reducing reaction of Si with exchangeable Al3+, is proposed as a potential explanation for the greater Si uptake into the shoot from this source. PMID:28555144

Enzymatic hydrolysis and fermentation of dilute acid pretreated cornstalk to biohydrogen

NASA Astrophysics Data System (ADS)

Pan, C. M.; Fan, Y. T.; Hou, H. W.

2010-03-01

The coupling method of acid pretreatment and enzymatic hydrolysis of cornstalk for hydrogen production was investigated in this study. Experimental results showed that temperature, pH and enzyme loading all had an individual significant influence on soluble sugar yield and Ps. The optimum condition for soluble sugar was close to that for Ps. The maximum hydrogen yield from cornstalk by anaerobic mixed microflora was 209.8 ml/g-TVS on the optimum enzymatic hydrolysis condition which was 52 °C of temperature, pH4.8 and 9.4 IU/g of enzyme loading.

Enhanced water-solubility, antibacterial activity and biocompatibility upon introducing sulfobetaine and quaternary ammonium to chitosan.

PubMed

Chen, Yuxiang; Li, Jianna; Li, Qingqing; Shen, Yuanyuan; Ge, Zaochuan; Zhang, Wenwen; Chen, Shiguo

2016-06-05

Chitosan (CS) has attracted much attention due to its good antibacterial activity and biocompatibility. However, CS is insoluble in neutral and alkaline aqueous solution, limiting its biomedical application to some extent. To circumvent this drawback, we have synthesized a novel N-quaternary ammonium-O-sulfobetaine-chitosan (Q3BCS) by introducing quaternary ammonium compound (QAC) and sulfobetaine, and its water-solubility, antibacterial activity and biocompatibility were evaluated compare to N-quaternary ammonium chitosan and native CS. The results showed that by introducing QAC, antibacterial activities and water-solubilities increase with degrees of substitution. The largest diameter zone of inhibition (DIZ) was improved from 0 (CS) to 15mm (N-Q3CS). And the water solution became completely transparent from pH 6.5 to pH 11; the maximal waters-solubility was improved from almost 0% (CS) to 113% at pH 7 (N-Q3CS). More importantly, by further introducing sulfobetaine, cell survival rate of Q3BCS increased from 30% (N-Q3CS) to 85% at 2000μg/ml, which is even greater than that of native CS. Furthermore, hemolysis of Q3BCS was dropped sharply from 4.07% (N-Q3CS) to 0.06%, while the water-solution and antibacterial activity were further improved significantly. This work proposes an efficient strategy to prepare CS derivatives with enhanced antibacterial activity, biocompatibility and water-solubility. Additionally, these properties can be finely tailored by changing the feed ratio of CS, glycidyl trimethylammonium chloride and NCO-sulfobetaine. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparation and Properties of Nanoparticles of Calcium Phosphates With Various Ca/P Ratios

PubMed Central

Sun, Limin; Chow, Laurence C.; Frukhtbeyn, Stanislav A.; Bonevich, John E.

2010-01-01

This study aimed at preparing and studying the properties of nanoparticles of calcium phosphate (nCaP) with Ca/P ratios ranging from 1.0 to 1.67 using a spray-drying technique. Micro-structural analyses suggested that the nCaPs with Ca/P ratios of 1.67 to 1.33 were nano-sized amorphous calcium phosphate (ACP) containing varying amounts of acid phosphate and carbonate. The nCaP with Ca/P ratio of 1 contained only nano-sized low crystalline dicalcium phosphate (DCP). BET measurements of the nCaPs showed specific surface areas of (12 ± 2 to 50 ± 1) m2/g, corresponding to estimated equivalent spherical diameters of (38 to 172) nm. However, dynamic light scattering measurements revealed much larger particles of (380 ± 49 to 768 ± 111) nm, owing to agglomeration of the smaller primary nano particles as revealed by Scanning Electron Microscopy (SEM). Thermodynamic solubility measurements showed that the nCaPs with Ca/P ratio of 1.33 – 1.67 all have similar solubility behavior. The materials were more soluble than the crystalline hydroxyapatite (HA) at pH greater than about 4.7, and more soluble than β-tricalcium phosphate (β-TCP), octacalcium phosphate (OCP) and DCP at pH above 5.5. Their solubility approached that of α-tricalcium phosphate (α-TCP) at about pH 7. These nCaPs, which cannot be readily prepared by other currently available methods for nanoparticle preparation, have potential biomedical applications. PMID:21037948

Effect of House Cricket (Acheta domesticus) Flour Addition on Physicochemical and Textural Properties of Meat Emulsion Under Various Formulations.

PubMed

Kim, Hyun-Wook; Setyabrata, Derico; Lee, YongJae; Jones, Owen G; Kim, Yuan H Brad

2017-12-01

The objective of this study was to determine the effect of house cricket (Acheta domesticus) flour addition on physicochemical and textural properties of meat emulsion under various formulations. As an initial marker of functionality, protein solubility, water absorption, emulsifying capacity, and gel formation ability of house cricket flour were determined at pH (2 to 10) and NaCl concentrations (0 to 2.10 M). Control emulsion was formulated with 60% lean pork, 20% back fat, and 20% ice. Six treatment emulsions were prepared with replacement of lean pork and/or back fat portions with spray-dried house cricket flour at 5% and 10% levels, based on a total sample weight. The protein solubility of house cricket flour (67 g protein/100 g) was significantly altered depending upon pH (P < 0.0001) and NaCl concentration (P = 0.0421). Similar water absorption capacity, emulsifying capacity, and gel formation ability of house cricket flour were found between 0 and 2.10 M NaCl concentration (P > 0.05). The replacement of lean meat/fat portion with house cricket flour within 10% level could fortify protein and some micronutrients (phosphorus, potassium, and magnesium) in meat emulsion, without negative impacts on cooking yield and textural properties. Our results suggest that house cricket flour can be used as an effective nonmeat functional ingredient to manufacture emulsified meat products. To better utilize house cricket flour as a food ingredient in wide application, understanding its technological properties in various pH, and ionic strength conditions is a pivotal step. Protein solubility of house cricket flour would be considerably affected by the varying pH and NaCl concentrations of applied conventional foods. In the case of meat emulsion, within 10% lean meat and/or fat portions could be successfully substituted with house cricket flour without detectable adverse impacts on technological properties associated with cooking yield and instrumental analysis of texture. Thus, our findings suggest that house cricket flour possess the necessary physical properties to be used as an alternative nonmeat ingredient for incorporation within emulsified meat products, which could be further explored in subsequent sensory-based studies. © 2017 Institute of Food Technologists®.

Coal fly ash as a source of iron in atmospheric dust.

PubMed

Chen, Haihan; Laskin, Alexander; Baltrusaitis, Jonas; Gorski, Christopher A; Scherer, Michelle M; Grassian, Vicki H

2012-02-21

Anthropogenic coal fly ash (FA) aerosol may represent a significant source of bioavailable iron in the open ocean. Few measurements have been made that compare the solubility of atmospheric iron from anthropogenic aerosols and other sources. We report here an investigation of iron dissolution for three FA samples in acidic aqueous solutions and compare the solubilities with that of Arizona test dust (AZTD), a reference material for mineral dust. The effects of pH, simulated cloud processing, and solar radiation on iron solubility have been explored. Similar to previously reported results on mineral dust, iron in aluminosilicate phases provides the predominant component of dissolved iron. Iron solubility of FA is substantially higher than of the crystalline minerals comprising AZTD. Simulated atmospheric processing elevates iron solubility due to significant changes in the morphology of aluminosilicate glass, a dominant material in FA particles. Iron is continuously released into the aqueous solution as FA particles break up into smaller fragments. These results suggest that the assessment of dissolved atmospheric iron deposition fluxes and their effect on the biogeochemistry at the ocean surface should be constrained by the source, environmental pH, iron speciation, and solar radiation.

Self-assembled multilayers and photoluminescence properties of a new water-soluble poly(para-phenylene)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, X.; Li, D.; Luett, M.

1998-07-01

This paper reports the synthesis and characterizations of a new water-soluble poly(paraphenylene) (PPP) and its applications in preparing self-assembled multi-layer films. This new water-soluble conducting polymer was prepared through the sulfonation reaction of poly(p-quarterphenylene-2,2{prime}-dicarboxylic acid). The incorporation of sulfonate groups has dramatically improved PPP's solubility in water at a wide pH range, whereas previous PPP is only slightly soluble in basic solutions. Dilute aqueous solutions of this polymer with acidic, neutral or basic pH emit brilliant blue light while irradiated with UV light. The sulfonated PPP emits from 350 nm to 455 nm with a maximum intensity at 380 nm.more » Self-assembled multilayers of this sulfonated PPP were constructed with a positively charged polymer poly(diallyl dimethyl ammonium chloride) and characterized with various surface analyses. Conductive (RuO{sub 2} and ITO), semiconductive (Si wafer), and non-conductive (SiO{sub 2}) substrates were used in the preparation of self-assembled multilayers. Electrical, optical and structural properties of these novel self-assembled thin films will be discussed.« less

Self-assembled multilayers and photoluminescence properties of a new water-soluble poly(para-phenylene)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, X.; Li, D.Q.; Luett, M.

1998-03-01

This paper reports the synthesis and characterizations of a new water-soluble poly(para-phenylene) (PPP) and its applications in preparing self-assembled multilayer films. This new water-soluble conducting polymer was prepared through the sulfonation reaction of poly(p-quarterphenylene-2,2{prime}-dicarboxylic acid). The incorporation of sulfonate groups has dramatically improved PPP`s solubility in water at a wide pH range, whereas previous PPP is only slightly soluble in basic solutions. Dilute aqueous solutions of this polymer with acidic, neutral or basic pH emit brilliant blue light while irradiated with UV light. The sulfonated PPP emits from 350 nm to 455 nm with a maximum intensity at 380 nm.more » Self-assembled multilayers of this sulfonated PPP were constructed with a positively charged polymer poly(diallyl dimethyl ammonium chloride) and characterized with various surface analyses. Conductive (RuO{sub 2} and ITO), semiconductive (Si wafer), and non-conductive (SiO{sub 2}) substrates were used in the preparation of self-assembled multilayers. Electrical, optical and structural properties of these novel self-assembled thin films will be discussed.« less

[Fast separation and analysis of water-soluble vitamins in spinach by capillary electrophoresis with high voltage].

PubMed

Hu, Xiaoqin; You, Huiyan

2009-11-01

In capillary electrophoresis, 0-40 kV (even higher) voltage can be reached by a connecting double-model high voltage power supply. In the article, water-soluble vitamins, VB1, VB2, VB6, VC, calcium D-pantothenate, D-biotin, nicotinic acid and folic acid in vegetable, were separated by using the high voltage power supply under the condition of electrolyte water solution as running buffer. The separation conditions, such as voltage, the concentration of buffer and pH value etc. , were optimized during the experiments. The results showed that eight water-soluble vitamins could be baseline separated in 2.2 min at 40 kV applied voltage, 25 mmol/L sodium tetraborate buffer solution (pH 8.8). The water-soluble vitamins in spinach were quantified and the results were satisfied. The linear correlation coefficients of the water-soluble vitamins ranged from 0.9981 to 0.9999. The detection limits ranged from 0.2 to 0.3 mg/L. The average recoveries ranged from 88.0% to 100.6% with the relative standard deviations (RSD) range of 1.15%-4.13% for the spinach samples.

Phase diagram of crystallization of Aspergillus niger acid proteinase A, a non-pepsin-type acid proteinase

NASA Astrophysics Data System (ADS)

Kudo, Norio; Ataka, Mitsuo; Sasaki, Hiroshi; Muramatsu, Tomonari; Katsura, Tatsuo; Tanokura, Masaru

1996-10-01

Proteinase A from Aspergillus niger var. macrosporus is a non-pepsin-type acid proteinase with an extremely low isoelectric point (pI 3.3). The protein is crystallized from ammonium sulfate solutions of pH lower than 4. The crystallization is affected by the presence of dimethylsulfoxide (DMSO). We have studied the phase diagram of the crystallization of proteinase A in the absence and presence of DMSO, to clarify crystallization at such an extremely low pH and to study the effects of DMSO. The results indicate that the logarithm of protein solubility is a rectilinear function of ammonium sulfate concentration in both the absence and presence of DMSO. DMSO definitely lowers the solubility at relatively low concentrations of ammonium sulfate, but had little effect on protein solubility at higher concentrations of ammonium sulfate.

Production of Star Fruit Alcoholic Fermented Beverage.

PubMed

Valim, Flávia de Paula; Aguiar-Oliveira, Elizama; Kamimura, Eliana Setsuko; Alves, Vanessa Dias; Maldonado, Rafael Resende

2016-12-01

Star fruit ( Averrhoa carambola ) is a nutritious tropical fruit. The aim of this study was to evaluate the production of a star fruit alcoholic fermented beverage utilizing a lyophilized commercial yeast ( Saccharomyces cerevisiae ). The study was conducted utilizing a 2 3 central composite design and the best conditions for the production were: initial soluble solids between 23.8 and 25 °Brix (g 100 g -1 ), initial pH between 4.8 and 5.0 and initial concentration of yeast between 1.6 and 2.5 g L -1 . These conditions yielded a fermented drink with an alcohol content of 11.15 °GL (L 100 L -1 ), pH of 4.13-4.22, final yeast concentration of 89 g L -1 and fermented yield from 82 to 94 %. The fermented drink also presented low levels of total and volatile acidities.

Chemical composition of polluted mist droplets

NASA Astrophysics Data System (ADS)

Igawa, Manabu; Kamijo, Kosuke; Nanzai, Ben; Matsumoto, Kiyoshi

2017-12-01

Mist events occur frequently worldwide, but the chemical characteristics of the mist droplets has never been investigated because of very low liquid water contents of them. We estimated the concentrations of the mist water, the average concentration of the mist droplets, via the determination of water-soluble components of the coarse aerosol and the observation of the imprints of the droplets on a MgO-coated glass slide. The pH of the mist water was estimated from the equilibrium calculation with the data of the Gran plot of the solution of the dissolved coarse particles, the inorganic ion concentrations of aerosol larger than 10 μm, and the estimated volume of mist water. The mist water was measured as about 1 eq/L total concentration for typical inorganic ions and about pH 4.5 in Yokohama. Such highly concentrated mist droplets may have intense environmental effects.

Desorption of Arsenic from Drinking Water Distribution System Solids

EPA Science Inventory

Given the limited knowledge regarding the soluble release of arsenic from DWDS solids, the objectives of this research were to: 1) investigate the effect of pH on the dissolution/desorption of arsenic from DWDS solids, and 2) examine the effect of orthophosphate on the soluble re...

Nutrient composition, mineral content and the solubility of the proteins of palm weevil, Rhynchophorus phoenicis f. (Coleoptera: Curculionidae)

PubMed Central

Omotoso, O.T.; Adedire, C.O.

2007-01-01

Adult (ADS) and larva stages of palm weevil Rhynchophorus phoenicis were analyzed for their nutritional potentials using proximate and mineral contents as indices. The early larva stage (ELS) contains the highest moisture content of 11.94% while ADS has the least value of 4.79%. The late larva stage (LLS) has the highest protein content of 10.51% while ADS contains 8.43%. Ash content is highest in ELS with a value of 2.37% and lowest in ADS with a value of 1.43%. ELS and LLS have the highest (22.14%) and lowest (17.22%) fibre contents respectively. The values of potassium, magnesium and iron in ELS were (455.00±21.21), (60.69±2.57) and (6.50±3.40) mg/kg while LLS recorded (457.50±10.61), (43.52±1.37) and (6.00±1.10) mg/kg and ADS recorded (372.50±24.75), (53.31±1.88) and (22.90±3.70) mg/kg. Chromium, phosphorus, nickel, calcium, lead, manganese and zinc were also detected. Copper was not detected in any of the samples. In all the developmental stages the protein solubilities were pH dependent with the minimum protein solubilities occurring at acidic pH while the maximum protein solubilities occurred at alkaline pH. PMID:17542059

Revisiting the pH Effect on Orthophosphate Control of Plumbosolvency

EPA Science Inventory

Although solubility models for Pb(II) have largely been successful for giving corrosion control treatment guidance for over 2 decades, very little systematic research has been done to precisely define plumbosolvency responses to changes in pH, carbonate and phosphate concentratio...

Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes

PubMed Central

Ch'ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab.

2014-01-01

In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments. PMID:25032229

Synthesis of Oligosaccharides Derived from Lactulose (OsLu) Using Soluble and Immobilized Aspergillus oryzae β-Galactosidase

PubMed Central

Cardelle-Cobas, Alejandra; Olano, Agustin; Irazoqui, Gabriela; Giacomini, Cecilia; Batista-Viera, Francisco; Corzo, Nieves; Corzo-Martínez, Marta

2016-01-01

β-Galactosidase from Aspergillus oryzae offers a high yield for the synthesis of oligosaccharides derived from lactulose (OsLu) by transgalactosylation. Oligosaccharides with degree of polymerization (DP) ≥ 3 have shown to possess higher in vitro bifidogenic effect than di- and tetrasaccharides. Thus, in this work, an optimization of reaction conditions affecting the specific selectivity of A. oryzae β-galactosidase for synthesis of OsLu has been carried out to enhance OsLu with DP ≥ 3 production. Assays with β-galactosidase immobilized onto a glutaraldehyde–agarose support were also carried out with the aim of making the process cost-effective and industrially viable. Optimal conditions with both soluble and immobilized enzyme for the synthesis of OsLu with DP ≥ 3 were 50 °C, pH 6.5, 450 g/L of lactulose, and 8 U/mL of enzyme, reaching yields of ca. 50% (w/v) of total OsLu and ca. 20% (w/v) of OsLu with DP 3, being 6′-galactosyl-lactulose the major one, after a short reaction time. Selective formation of disaccharides, however, was favored at 60 °C, pH 4.5, 450 g/L of lactulose and 8 U/mL of enzyme. Immobilization increased the enzymatic stability to temperature changes and allowed to reuse the enzyme. We can conclude that the use, under determined optimal conditions, of the A. oryzae β-galactosidase immobilized on a support of glutaraldehyde–agarose constitutes an efficient and cost-effective alternative to the use of soluble β-galactosidases for the synthesis of prebiotic OsLu mixtures. PMID:27014684

Characterization of LY3023414, a Novel PI3K/mTOR Dual Inhibitor Eliciting Transient Target Modulation to Impede Tumor Growth.

PubMed

Smith, Michele C; Mader, Mary M; Cook, James A; Iversen, Philip; Ajamie, Rose; Perkins, Everett; Bloem, Laura; Yip, Yvonne Y; Barda, David A; Waid, Philip P; Zeckner, Douglas J; Young, Debra A; Sanchez-Felix, Manuel; Donoho, Gregory P; Wacheck, Volker

2016-10-01

The PI3K/AKT/mTOR pathway is among the most frequently altered pathways in cancer cell growth and survival. LY3023414 is a complex fused imidazoquinolinone with high solubility across a wide pH range designed to inhibit class I PI3K isoforms and mTOR kinase. Here, we describe the in vitro and in vivo activity of LY3023414. LY3023414 was highly soluble at pH 2-7. In biochemical testing against approximately 266 kinases, LY3023414 potently and selectively inhibited class I PI3K isoforms, mTORC1/2, and DNA-PK at low nanomolar concentrations. In vitro, inhibition of PI3K/AKT/mTOR signaling by LY3023414 caused G 1 cell-cycle arrest and resulted in broad antiproliferative activity in cancer cell panel screens. In vivo, LY3023414 demonstrated high bioavailability and dose-dependent dephosphorylation of PI3K/AKT/mTOR pathway downstream substrates such as AKT, S6K, S6RP, and 4E-BP1 for 4 to 6 hours, reflecting the drug's half-life of 2 hours. Of note, equivalent total daily doses of LY3023414 given either once daily or twice daily inhibited tumor growth to similar extents in multiple xenograft models, indicating that intermittent target inhibition is sufficient for antitumor activity. In combination with standard-of-care drugs, LY3023414 demonstrated additive antitumor activity. The novel, orally bioavailable PI3K/mTOR inhibitor LY3023414 is highly soluble and exhibits potent in vivo efficacy via intermittent target inhibition. It is currently being evaluated in phase I and II trials for the treatment of human malignancies. Mol Cancer Ther; 15(10); 2344-56. ©2016 AACR. ©2016 American Association for Cancer Research.

Effect of hydrolysis enzymatic process of corn using protease crude (Rhizopus oligosporus-C1) to produce corn hydrolisate rich folic acid

NASA Astrophysics Data System (ADS)

Maryati, Yati; Susilowati, Agustine; Melanie, Hakiki; Lotulung, Puspa D.

2017-11-01

Corn hydrolyzate (Zea mays L) as a functional food fortificant derived from natural folic acid has been evaluated through a hydrolysis process using protease enzyme Rhizopus oligosporus strain C1. Enzymatic hydrolysis was carried out on two types of corn; yellow and white pearl variety corn, at concentration of protease enzyme (rough) 0.025; 0.125; and 0.225% (v/w of soluble nixtamal corn protein) with a hydrolysis time of 24 h at 30 °C, and pH 5.0. The results showed that the concentration of protease enzymes can increase the folic acid to the optimum condition, from the beginning to the end of the process time. Folic acid optimization of hydrolysis results in each corn was at the concentration of protease enzyme 0.225% (v/w of soluble nixtamal corn protein) in white corn and yellow corn at 24 hours hydrolysis, with folic acid composition, 283.56 µg/mL and 412.52 µg/mL, 1.07 and 1.04 mg/mL of soluble proteins, proteolytic activity 2.09 and 2.06 U/mL, total solids of 21.74 and 17.85%, total sugars of 0.56 and 2.22 mg/mL, and reducing sugar 91.72 and 48.47 mg/mL. In this condition, the increase of optimum folic acid for white corn was 33.57% and for yellow corn was 71.60% after hydrolysis.

Synergistic and Antagonistic Effects of Salinity and pH on Germination in Switchgrass (Panicum virgatum L.)

PubMed Central

Liu, Yuan; Wang, Quanzhen; Zhang, Yunwei; Cui, Jian; Chen, Guo; Xie, Bao; Wu, Chunhui; Liu, Haitao

2014-01-01

The effects of salt-alkaline mixed stress on switchgrass were investigated by evaluating seed germination and the proline, malondialdehyde (MDA) and soluble sugar contents in three switchgrass (Panicum virgatum L.) cultivars in order to identify which can be successfully produced on marginal lands affected by salt-alkaline mixed stress. The experimental conditions consisted of four levels of salinity (10, 60, 110 and 160 mM) and four pH levels (7.1, 8.3, 9.5 and 10.7). The effects of salt-alkaline mixed stress with equivalent coupling of the salinity and pH level on the switchgrass were explored via model analyses. Switchgrass was capable of germinating and surviving well in all treatments under low-alkaline pH (pH≤8.3), regardless of the salinity. However, seed germination and seedling growth were sharply reduced at higher pH values in conjunction with salinity. The salinity and pH had synergetic effects on the germination percentage, germination index, plumular length and the soluble sugar and proline contents in switchgrass. However, these two factors exhibited antagonistic effects on the radicular length of switchgrass. The combined effects of salinity and pH and the interactions between them should be considered when evaluating the strength of salt-alkaline mixed stress. PMID:24454834

The stability of water- and fat-soluble vitamin in dentifrices according to pH level and storage type.

PubMed

Park, Jung-Eun; Kim, Ki-Eun; Choi, Yong-Jun; Park, Yong-Duk; Kwon, Ha-Jeong

2016-02-01

The purpose of this study is to evaluate the vitamin stabilities in dentifrices by analyzing various vitamins according to the level and storage temperature. The stabilities of water- and fat-soluble vitamins were investigated in buffer solution at different pH values (4, 7, 8, 10 and 11) for 14 days and in dentifrices at different pH (7 and 10) for 5 months at two temperature conditions (room and refrigeration temperature) by analyzing the remaining amounts using HPLC methods. In the buffer solution, the stability of vitamins B1 , B6 and C was increased as the pH values increased. Vitamins E and K showed poor stability at pH 4, and vitamin B3 showed poor stability at pH 11. In dentifrices, the storage temperature highly influenced vitamin stability, especially vitamins C and E, but the stabilities of vitamins B1 and C according to pH values did not correspond to the buffer solution tests. Vitamin B group was relatively stable in dentifrices, but vitamin C completely disappeared after 5 months. Vitamin K showed the least initial preservation rates. Vitamins were not detected in commercial dentifrices for adults and detected amounts were less than the advertised contents in dentifrices for children. Copyright © 2015 John Wiley & Sons, Ltd.

Use of cold microfiltration retentates produced with polymeric membranes for standardization of milks for manufacture of pizza cheese.

PubMed

Govindasamy-Lucey, S; Jaeggi, J J; Johnson, M E; Wang, T; Lucey, J A

2007-10-01

Pizza cheese was manufactured with milk (12.1% total solids, 3.1% casein, 3.1% fat) standardized with microfiltered (MF) and diafiltered retentates. Polymeric, spiral-wound MF membranes were used to process cold (<7 degrees C) skim milk, and diafiltration of MF retentates resulted in at least 36% removal of serum protein on a true protein basis. Cheese milks were obtained by blending the MF retentate (16.4% total solids, 11.0% casein, 0.4% fat) with whole milk (12.1% total solids, 2.4% casein, 3.4% fat). Control cheese was made with part-skim milk (10.9% total solids, 2.4% casein, 2.4% fat). Initial trials with MF standardized milk resulted in cheese with approximately 2 to 3% lower moisture (45%) than control cheese ( approximately 47 to 48%). Cheese-making procedures (cutting conditions) were then altered to obtain a similar moisture content in all cheeses by using a lower setting temperature, increasing the curd size, and lowering the wash water temperature during manufacture of the MF cheeses. Two types of MF standardized cheeses were produced, one with preacidification of milk to pH 6.4 (pH6.4MF) and another made from milk preacidified to pH 6.3 (pH6.3MF). Cheese functionality was assessed by dynamic low-amplitude oscillatory rheology, University of Wisconsin MeltProfiler, and performance on pizza. Nitrogen recoveries were significantly higher in MF standardized cheeses. Fat recoveries were higher in the pH6.3MF cheese than the control or pH6.4MF cheese. Moisture-adjusted cheese yield was significantly higher in the 2 MF-fortified cheeses compared with the control cheese. Maximum loss tangent (LT(max)) values were not significantly different among the 3 cheeses, suggesting that these cheeses had similar meltability. The LT(max) values increased during ripening. The temperature at which the LT(max) was observed was highest in control cheese and was lower in the pH6.3MF cheese than in the pH6.4MF cheese. The temperature of the LT(max) decreased with age for all 3 cheeses. Values of 12% trichloroacetic acid soluble nitrogen levels were similar in all cheeses. Performance on pizza was similar for all cheeses. The use of MF retentates derived with polymeric membranes was successful in increasing cheese yield, and cheese quality was similar in the control and MF standardized cheeses.

An analysis of manganese as an indicator for heavy metal removal in passive treatment using laboratory spent mushroom compost columns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobson, B.A.; Unz, R.F.; Dempsey, B.A.

1999-07-01

The National Pollution Discharge Elimination System (NPDES) dictates removal of manganese in mine drainage to less than 4 mg/1 daily or less than 2 mg/1 on a monthly average. Owing to its high solubility at low and circumneutral pH, removal of manganese is often the most difficult of the NPDES discharge standards. This has lead to the use of Mn(II) as a surrogate for metal removal. However, recent studies concluded that zinc or nickel may be more appropriate indicators for removal of other metals. Previous field studies showed zinc removal to be highly correlated to the removal of copper, cobalt,more » and nickel in a sulfate reducing subsurface loaded wetland, whereas manganese removal was poorly correlated. The objective of this study was to evaluate zinc and manganese retention under sulfate reducing conditions in bench scale columns containing fresh spent mushroom compost. Column effluent data were analyzed using an EPA geochemical computer model (MINTEQ) over the pH range of 6.0 to 6.8. Under these conditions, zinc and manganese displayed distinctly reactivities. Zn(II) was supersaturated with respect to ZnS{sub s} and the Zn(HS){sub 2}{degree} and Zn(HS){sub 3}{sup minus} complexes dominated solubility. Soluble zinc concentrations were inversely correlated to sulfide. Mn(II) remained as soluble Mn{sup +2}. During early column operation at pH > 7, MnCO{sup 3(s)} was supersaturated. Manganese concentrations did not correlate with pH or sulfide. Given these fundamental differences in removal mechanisms between Zn and Mn under sulfate reducing conditions, the use of manganese removal as a surrogate for heavy metal removal in passive treatment of mine drainage seems unjustified.« less

The effect of pH, buffer capacity and ionic strength on quetiapine fumarate release from matrix tablets prepared using two different polymeric blends.

PubMed

Hamed, Rania; AlJanabi, Reem; Sunoqrot, Suhair; Abbas, Aiman

2017-08-01

The objective of this study was to investigate the effect of the different physiological parameters of the gastrointestinal (GI) fluid (pH, buffer capacity, and ionic strength) on the in vitro release of the weakly basic BCS class II drug quetiapine fumarate (QF) from two once-a-day matrix tablet formulations (F1 and F2) developed as potential generic equivalents to Seroquel ® XR. F1 tablets were prepared using blends of high and low viscosity grades of hydroxypropyl methylcellulose (HPMC K4M and K100LV, respectively), while F2 tablets were prepared from HPMC K4M and PEGylated glyceryl behenate (Compritol ® HD5 ATO). The two formulations attained release profiles of QF over 24 h similar to that of Seroquel ® XR using the dissolution medium published by the Food and Drug Administration (FDA). A series of solubility and in vitro dissolution studies was then carried out using media that simulate the gastric and intestinal fluids and cover the physiological pH, buffer capacity and ionic strength range of the GIT. Solubility studies revealed that QF exhibits a typical weak base pH-dependent solubility profile and that the solubility of QF increases with increasing the buffer capacity and ionic strength of the media. The release profiles of QF from F1, F2 and Seroquel ® XR tablets were found to be influenced by the pH, buffer capacity and ionic strength of the dissolution media to varying degrees. Results highlight the importance of studying the physiological variables along the GIT in designing controlled release formulations for more predictive in vitro-in vivo correlations.

Solubility, Stability, Physicochemical Characteristics and In Vitro Ocular Tissue Permeability of Hesperidin: a Natural Bioflavonoid

PubMed Central

Majumdar, Soumyajit; Srirangam, Ramesh

2008-01-01

Purpose Hesperidin holds potential in treating age-related macular degeneration, cataract and diabetic retinopathy. The aim of this study, constituting the first step towards efficient ocular delivery of hesperidin, was to determine its physicochemical properties and in vitro ocular tissue permeability. Methods pH dependent aqueous solubility and stability were investigated following standard protocols. Permeability of hesperidin across excised rabbit cornea, sclera, and sclera plus retinal pigmented epithelium (RPE) was determined using a side-bi-side diffusion apparatus. Results Hesperidin demonstrated poor, pH independent, aqueous solubility. Solubility improved dramatically in the presence of 2-hydroxypropyl-beta-cyclodextrin (HP-β-CD) and the results supported 1:1 complex formation. Solutions were stable in the pH and temperature (25, 40°C) conditions tested, except for samples stored at pH 9. Transcorneal permeability in the apical-basal and basal-apical directions was 1.11±0.86×10−6 and 1.16±0.05×10−6 cm/s, respectively. The scleral tissue was more permeable (10.2±2.1×10−6cm/s). However, permeability across sclera/choroid/RPE in the sclera to retina and retina to sclera direction was 0.82±0.69×10−6, 1.52±0.78×10−6 cm/s, respectively, demonstrating the barrier properties of the RPE. Conclusion Our results suggest that stable ophthalmic solutions of hesperidin can be prepared and that hesperidin can efficiently permeate across the corneal tissue. Further investigation into its penetration into the back-of-the eye ocular tissues is warranted. PMID:18810327

Determination of physicochemical properties and degradation kinetics of triamcinolone acetonide palmitate in vitro.

PubMed

Peng, Cuilian; Liu, Cong; Tang, Xing

2010-12-01

Triamcinolone acetonide palmitate (TAP) is a lipophilic prodrug of triamcinolone acetonide (TAA) to improve the insoluble TAA physicochemical properties for the preparation of emulsions. This investigation has focused on the preformulation study of TAP, including its physicochemical properties and hydrolysis kinetics in vitro. The solubility of TAP in medium-chain triglyceride is about twice greater than that in soybean oil (long-chain triglyceride) (19.17 versus 9.55 mg/g) at 25°C, and in all investigated cases, lecithin (80, 160, and 240 mg/g) as solubilizer provided increased solubility of drugs in medium-chain triglyceride and long-chain triglyceride, whereas the maximum water solubility of TAP was 0.10 μg/mL. The partition coefficient (log P) of TAP was 5.79 irrespective of the pH conditions. The hydrolysis of TAP followed pseudo-first-order kinetics in aqueous solutions, and the stable pH range was from pH 5.0 to 9.0. The in vitro enzymolysis kinetics of TAP in rat plasma and liver homogenate was evaluated by measuring the decrease of TAP as well as the increase of TAA at 37°C for 96 hours. The results demonstrated that the TAP may be hydrolyzed mainly by rat plasma esterase and, to a minor extent, by liver esterase, and the hydrolysis half-life of TAP in 100% rat plasma was 17.53 ± 6.85 hours at pH 7.4. All these results indicated that TAP had successfully obtained higher lipid-soluble property for the preparation of intravenous emulsion and may be an effective prodrug for sustained release of TAA in vivo.

Fine particle water and pH in the Eastern Mediterranean: Sources, variability and implications for nutrients availability

NASA Astrophysics Data System (ADS)

Bougiatioti, Aikaterini; Nikolaou, Panayiota; Stavroulas, Iasonas; Kouvarakis, Giorgos; Nenes, Athanasios; Weber, Rodney; Kanakidou, Maria; Mihalopoulos, Nikolaos

2016-04-01

Atmospheric particles have the ability to absorb significant amounts of water, which greatly impacts on their physical and chemical properties. Direclty linked to aerosol pH and LWC is the bioavailability of nutrients contained within mineral dust, involving pH-dependent catalyzed redox-reaction pathways. Liquid water content (LWC) and pH, even though are important constituents of the aerosol phase, are rarely monitored. Direct measurements of aerosol pH "in situ" are scarce and require considerations owing to the non-conserved nature of the hydronium ion and partial dissociation of inorganic and organic electrolytes in the aerosol. To overcome these challenges, indirect alternatives such as measuring the semi-volatile partitioning of key species sensitive to pH, combined with comprehensive models are used to provide a reasonably accurate estimate of pH that can be carried out with routine measurements. Using concurrent measurements of aerosol chemical composition, tandem light scattering coefficients and the thermodynamic model ISORROPIA-II, LWC mass concentrations associated with the aerosol inorganic and organic components are determined for the remote background site of Finokalia, Crete. The predicted water was subsequently compared to the one measured by the ambient versus dry light scattering coefficients. The sum of Winorg and Worg was highly correlated and in close agreement with the measured LWC (on average within 10%), with slope 0.92 (R2=0.8) for the whole measurement period between August and November 2012 (n=5201 points). As expected, the highest fine aerosol water values are observed during night-time, when RH is at its maximum, resulting in important water uptake. The average concentration of total aerosol water was found to be 2.19±1.75 μg m-3, which according to the dry mass measurements, can contribute on average up to 33% to the total aerosol submicron mass. The average Worg was found to be 0.56±0.37 μg m-3, which constitutes about 28% of the total calculated water. Particle pH is also calculated with the help of ISORROPIA-II, and during the studied period, values varied from 0.5 to 2.8, indicating that the aerosol was highly acidic. pH values were also studied depending on the source/origin of the sampled air masses and biomass burning aerosol was found to exhibit the highest values of PM1 pH and the lowest values in total water mass concentrations. The two natural sources, namely mineral and marine origin, contained the largest amounts of total submicron water and the lowest contribution of organic water, as expected. The low pH values estimated for the studied period in the submicron mode and independently of the air masses' origin could potentially have important implications for nutrient availability, especially for phosphorus solubility, which is the nutrient limiting sea water productivity of the Eastern Mediterranean.

Response of aluminum solubility to elevated nitrification in soil of a red spruce stand in eastern Maine

USGS Publications Warehouse

Lawrence, G.B.; David, M.B.

1997-01-01

Elevated concentrations of soluble Al can impair tree growth and be toxic to aquatic biota, but effects of acidic deposition on Al solubility in forest soils are only partially understood because of complex interactions with H+ and organic matter. We therefore evaluated Al solubility in two red spruce stands in eastern Maine, one of which received dry (NH4)2SO4 at a rate of 1800 equiv ha-1 yr-1 during 19891995. Samples of soil (Spodosol Oa and Bh horizons) and soil solution were collected on five dates from 1992 to 1995. The treatment elevated nitrification, causing an increase in acid input that led to inorganic Al concentrations of greater than 60 ??mol L-1 in both the Oa and Bh horizons. Solubility of Al was also lower in the Bh horizon of the treated stand than in the reference stand, a response related to higher DOC concentrations in the treated stand. Concentrations of CuCl2 and pyrophosphate-extractable Al were higher in the Oa horizon of the treated watershed than the reference stand, a result of accelerated weathering of mineral particles caused by lower solution pH in the treated stand (3.47) than in the reference stand (3.69). Dissolved Al concentrations in these soils are the result of complex mechanisms through which mineral matter, organic matter, and pH interact to control Al solubility; mechanisms that are not incorporated in current Al solubility models.

Effects of soy sauce on physicochemical and textural properties of tumbled chicken breast.

PubMed

Kim, H W; Hwang, K E; Song, D H; Kim, Y J; Lim, Y B; Choi, J H; Choi, Y S; Kim, H Y; Kim, C J

2014-03-01

The objective of this study was to evaluate the effects of soy sauce on the physicochemical and textural properties of tumbled chicken breasts. Chicken breasts marinated with distilled water (Con), 4% NaCl solution, 4% NaCl and lactic acid solution (pH 4.9), and soy sauce solution (4% salt concentration and pH 4.9) were vacuum tumbled at 3°C for 60 min. The chicken breast marinated with soy sauce solution showed lower lightness and higher redness and yellowness due to the color of the soy sauce. The acidic marinades led to a decrease in pH value of tumbled chicken breast. The acidic marinades increased collagen solubility of sample compared with 4% NaCl solution, resulting in decreased shear force. Water-holding capacity, marination and cooking yields, and solubility of myofibrillar proteins were mainly affected by the presence of salt in the marinade, rather than by pH alternation. Our results suggested that soy sauce marination can improve the tenderness of tumbled chicken breast.

Effect of pH on the functional properties of Arthrospira (Spirulina) platensis protein isolate.

PubMed

Benelhadj, Sonda; Gharsallaoui, Adem; Degraeve, Pascal; Attia, Hamadi; Ghorbel, Dorra

2016-03-01

In the present study, a protein isolate extracted from Arthrospira platensis by isoelectric precipitation was evaluated for its functional properties. The maximum nitrogen solubility was 59.6±0.7% (w/w) at pH 10. The A. platensis protein isolate (API) showed relatively high oil (252.7±0.3g oil/100g API) and water (428.8±15.4g of water/100g of API at pH 10) absorption capacities. The protein zeta potential, the emulsifying capacity, the emulsion ageing stability, the emulsion microstructure and the emulsion opacity as well as the foaming capacity and the foam stability were shown to be greatly affected by pH. Especially, emulsifying and foaming capacities were positively correlated to the protein solubility. Moreover, the API was able to form films when sorbitol (30% (w/w)) was used as plasticizer and to form gels when the API concentration exceeded 12% (w/w). Copyright © 2015 Elsevier Ltd. All rights reserved.

Remediation of antimony-rich mine waters: Assessment of antimony removal and shifts in the microbial community of an onsite field-scale bioreactor.

PubMed

Sun, Weimin; Xiao, Enzong; Kalin, Margarete; Krumins, Valdis; Dong, Yiran; Ning, Zengping; Liu, Tong; Sun, Min; Zhao, Yanlong; Wu, Shiliang; Mao, Jianzhong; Xiao, Tangfu

2016-08-01

An on-site field-scale bioreactor for passive treatment of antimony (Sb) contamination was installed downstream of an active Sb mine in Southwest China, and operated for one year (including a six month monitoring period). This bioreactor consisted of five treatment units, including one pre-aerobic cell, two aerobic cells, and two microaerobic cells. With the aerobic cells inoculated with indigenous mine water microflora, the bioreactor removed more than 90% of total soluble Sb and 80% of soluble antimonite (Sb(III)). An increase in pH and decrease of oxidation-reduction potential (Eh) was also observed along the flow direction. High-throughput sequencing of the small subunit ribosomal RNA (SSU rRNA) gene variable (V4) region revealed that taxonomically diverse microbial communities developed in the bioreactor. Metal (loid)-oxidizing bacteria including Ferrovum, Thiomonas, Gallionella, and Leptospirillum, were highly enriched in the bioreactor cells where the highest total Sb and Sb(III) removal occurred. Canonical correspondence analysis (CCA) indicated that a suite of in situ physicochemical parameters including pH and Eh were substantially correlated with the overall microbial communities. Based on an UPGMA (Unweighted Pair Group Method with Arithmetic Mean) tree and PCoA (Principal Coordinates Analysis), the microbial composition of each cell was distinct, indicating these in situ physicochemical parameters had an effect in shaping the indigenous microbial communities. Overall, this study was the first to employ a field-scale bioreactor to treat Sb-rich mine water onsite and, moreover, the findings suggest the feasibility of the bioreactor in removing elevated Sb from mine waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of edible coating with starch and carvacrol in minimally processed pumpkin.

PubMed

Santos, Adriele R; da Silva, Alex F; Amaral, Viviane C S; Ribeiro, Alessandra B; de Abreu Filho, Benicio A; Mikcha, Jane M G

2016-04-01

The present study evaluated the effect of an edible coating of cassava starch and carvacrol in minimally processed pumpkin (MPP). The minimal inhibitory concentration (MIC) of carvacrol against Escherichia coli, Salmonella enterica serotype Typhimurium, Aeromonas hydrophila, and Staphylococcus aureus was determined. The edible coating that contained carvacrol at the MIC and 2 × MIC was applied to MPP, and effects were evaluated with regard to the survival of experimentally inoculated bacteria and autochthonous microflora in MPP. Total titratable acidity, pH, weight loss, and soluble solids over 7 days of storage under refrigeration was also analyzed. MIC of carvacrol was 312 μg/ml. Carvacrol at the MIC reduced the counts of E. coli and S. Typhimurium by approximately 5 log CFU/g. A. hydrophila was reduced by approximately 8 log CFU/g, and S. aureus was reduced by approximately 2 log CFU/g on the seventh day of storage. Carvacrol at the 2 × MIC completely inhibited all isolates on the first day of Storage. coliforms at 35 °C and 45 °C were not detected (< 3 MPN/g) with either treatment on all days of shelf life. The treatment groups exhibited a reduction of approximately 2 log CFU/g in psychrotrophic counts compared with controls on the last day of storage. Yeast and mold were not detected with either treatment over the same period. The addition of carvacrol did not affect total titratable acidity, pH, or soluble solids and improved weight loss. The edible coating of cassava starch with carvacrol may be an interesting approach to improve the safety and microbiological quality of MPP.

Emergence and growth of plant species in coal mine soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Day, A.D.; Mitchell, G.F.; Tucker, T.C.

1979-01-01

Experiments were conducted in the laboratory and greenhouse in Arizona with the following objectives: to evaluate the chemical properties of undisturbed soil, surface-mined coal land (coal mine soil) on the Black Mesa Coal Mine, and Gila loam soil; and to study the emergence of seven plant species in the greenhouse in Gila loam soil and coal mine soil. The pH of coal mine soil (6.2) was lower than the pH of undisturbed soil (7.5) or Gila loam (7.6). The total soluble salts in coal mine soil (3241) and undisturbed soil (4592) were much higher than in Gila loam (378); however,more » coal mine soil was lower in total soluble salts than undisturbed soil. The nitrogen content of coal mine soil was higher than the nitrogen content of undisturbed soil or gila loam. Emergence percentages for seven plant species grown in coal mine soil were similar to emergence percentages for the same species grown in Gila loam. Alfalfa (Medicago sativa L.), barley (Hordeum vulgare L.), and wheat (Triticum aestivum L. em Thell.) had from 84 to 93% emergence in coal mine soil. Indian ricegrass (Oryzopsis hymenoides Roem. and Shult), fourwing saltbush (Atriplex canescens Pursh), yellow sweetclover (Melilotus officinalis Lam.), and winterfat (Euroti lanata Pursh.) emerged <35% in coal mine soil and Gila loam. Plant growth data from forage species grown in the greenhouse indicate that coal mine soil has a lower fertility level than does Gila loam soil. When supplied with optimum soil moisture and plant nutrients, coal mine soil produced approximately the same yields of forage from alfalfa, barley, and wheat as were produced in Gila loam under the same soil-moisture and fertility conditions.« less

Utilization of α-amylase enzyme from Bacillus stearothermophilus RSAII1B for maltodextrin production from sago starch

NASA Astrophysics Data System (ADS)

Arfah, R. A.; Ahmad, A.; Dali, S.; Djide, M. N.; Mahdalia; Arif, A. R.

2018-03-01

The dried sago flour derived from Palopo contains 28.80% amylose and 91.23% total carbohydrate. Based on the data, sago starch has the potential to become an alternative raw material for themaltodextrin production. Maltodextrin is one of the starch derivative products produced by hydrolysis process using the α-amylase enzyme with amaximum DE (dextrose equivalent) value of 20. The use of maltodextrin for food and pharmaceutical industries is increasing because of maltodextrin is widely used as thickener filler, surfactant and sugar substitute in milk powder. The aims of this study are to optimize the addition of enzyme concentration and hydrolysis time of α -amylase enzyme to obtain high quality ofmaltodextrin This study also aimed to characterization the obtained maltodextrin. The first step was isolation and purification α-amylase from the isolate of Bacillus stearothermophilus RSAII1B, followed by determination of the α-amylase concentration (0.05%, 0.07% and 0.09%) in 2.0% starch substrate, and the hydrolysis time ofα-amilase (60, 90, 120, 240 minutes). Maltodextrin characters observed were dextrose equivalent (DE), reducing sugar, moisture content, pH changes, color, solubility, viscosity, and total plate count (TPC). The results showed that the value of DE was 12.31, reducing sugar was 11.4%; water content was 10.92%; pH was 4.85; The color of maltodextrin powder was white bone color; solubility was 153.2 g/L; Viscositywas 210-240 cps, TPCwas 380 cfu/g. Maltodextrins produced from sago starch using the α-amylase enzyme from B.stearothermophillus RSAIIm met the quality requirements of SNI 7599: 2010.

Impacts of post-mortem ageing prior to freezing on technological and oxidative properties of coarse ground lamb sausage in a model system.

PubMed

Choe, Juhui; Kim, Hyun-Wook; Farouk, Mustafa M; Brad Kim, Yuan H

2017-07-01

The objective of this study was to evaluate the effects of ageing time of lamb loins prior to freezing on technological characteristics and oxidation stability of coarse ground lamb loin sausage using in a model system. Lamb loins ( M. longissimus lumborum , n = 25) were aged at -1.5°C for 0, 1, 2, 3, and 8 wk and then frozen for the remaining days (a total of 30 wk). The aged/frozen/thawed lamb loins were ground, and model sausages were formulated with 75% aged/frozen/thawed lamb loin, 25% water, 1.5% sodium chloride (NaCl) and 0.3% sodium tripolyphosphate. The pH and thaw/purge loss of aged/frozen/thawed lamb loins were evaluated, and protein functionality (protein solubility and emulsifying capacity), water-holding capacity and textural properties of model sausages were determined. Cooked model sausages were vacuum-packaged in a plastic bag and displayed under continuous fluorescent natural white light (3°C±1°C). Colour and lipid oxidation of the cooked model sausages were evaluated on 0 and 21 d of display storage. Ageing prior to freezing had no impact on pH and purge/thaw loss of lamb loins and the colour of cooked sausages (p>0.05) made from the loins. Lamb loins aged for at least 3 wk prior to freezing numerically improved total and myofibrillar protein solubilities (p>0.05) and emulsion activity index (p = 0.009) of meat batter, but decreased cooking loss (p = 0.003) and lipid oxidation (p<0.05) of model sausages. This study suggests that post-mortem ageing of raw meat prior to freezing could improve water-holding capacity and lipid oxidative stability of sausage made from the meat.

[Fluorine speciation and its distribution characteristics in selected agricultural soils of North China Plain].

PubMed

Yi, Chun-Yao; Wang, Bing-Guo; Jin, Meng-Gui

2013-08-01

The objectives of this study were to study fluorine speciation and its distribution characteristics in the cultivated soils of wheat-corn fields at the typical areas, the North China Plain. The fluorine contents in cultivated soils and profile soils were measured by consecutive extraction. The results showed that the soil total fluorine (T-F) content at typical areas in the North China Plain ranged from 338.31 mg x kg(-1) to 781.67 mg x kg(-1), with a mean of 430.46 mg x kg(-1). The soil fluorine speciation with the highest content was Residual-Fluorine (Res-F), with a mean of 402.73 mg x kg(-1). The average content of Water soluble Fluorine (Ws-F) was 14.39 mg x kg(-1). The result indicated that the cultivated soil in the study area was at a relatively high fluoride pollution level, which may be harmful to human health and the ecological environment. The contents of Organic Fluorine (Or-F) and Fe/Mn Oxide-Fluorine (Fe/ Mn-F) were also quite high, with a mean of 8.90 mg x kg(-1) and 4.10 mg x kg(-1), respectively. The exchangeable fluorine (Ex-F) only had a very small amount of 0.33 mg x kg(-1). Soil Ws-F was positively correlated with soil pH and CEC, while it was negatively correlated with the percentage of soil clay. The content of soil Fe/Mn-F was positively correlated with soil pH, CEC and the sand grain content percentage, while it was negatively correlated with the clay grain content percentage. The soil pH value had the most significant influence on the water soluble fluorine (Ws-F) and Fe/Mn Oxide-Fluorine (Fe/Mn-F), and the soil CEC had the most significant influence on the soil total fluorine (T-F) and residual-Fluorine (Res-F) by stepwise regression analysis. In the soil profiles, the T-F content appeared as peaks and valleys representing the change of the soil lithology in the vadose zone. The Ws-F in the soil profiles mainly changed in the depth of 0-100 cm near the surface soil and was little influenced by the soil lithology. But it was strongly influenced by the soil pH, and was positively correlated with the soil pH. This study can provide a scientific evidence for soil fluorine pollution, prevention and a theoretical basis for soil fluorine mobility and its influence on ecology and environment.

Hematin crystallization from aqueous and organic solvents

NASA Astrophysics Data System (ADS)

Ketchum, Megan A.; Olafson, Katy N.; Petrova, Elena V.; Rimer, Jeffrey D.; Vekilov, Peter G.

2013-09-01

Hematin crystallization is the main mechanism of detoxification of heme that is released in malaria-infected erythrocytes as a byproduct of the hemoglobin catabolism by the parasite. A controversy exists over whether hematin crystals grow from the aqueous medium of the parasite's digestive vacuole or in the lipid bodies present in the vacuole. To this end, we compare the basic thermodynamic and structural features of hematin crystallization in an aqueous buffer at pH 4.8, as in the digestive vacuole, and in water-saturated octanol that mimics the environment of the lipid nanospheres. We show that in aqueous solutions, hematin aggregation into mesoscopic disordered clusters is insignificant. We determine the solubility of the β-hematin crystals in the pH range 4.8-7.6. We image by atomic force microscopy crystals grown at pH 4.8 and show that their macroscopic and mesoscopic morphology features are incompatible with those reported for biological hemozoin. In contrast, crystals grown in the presence of octanol are very similar to those extracted from parasites. We determine the hematin solubility in water-saturated octanol at three temperatures. These solubilities are four orders of magnitude higher than that at pH 4.8, providing for faster crystallization from organic than from aqueous solvents. These observations further suggest that the lipid bodies play a role in mediating biological hemozoin crystal growth to ensure faster heme detoxification.

Experiments on the Multiphase Chemistry of Isocyanic Acid, HNCO.

NASA Astrophysics Data System (ADS)

Roberts, J. M.; Liu, Y.

2015-12-01

Isocyanic acid, HNCO, has emerged as a potentially important reduced nitrogen compound that is emitted in wildfires, and may have health effect implications. The extent of the health effects depends on the solubility of HNCO in aqueous and non-aqueous solutions and the relative rates of hydrolysis versus carbamylation reactions (for example: HNCO + ROH => H2NC(O)OR). We report here results of studies of HNCO solubility and its reaction in buffered aqueous solutions (pH3), tridecane, and n-octanol at temperatures over the range 5 to 37°C. From these data, the heats of solution and activation energy of hydrolysis are estimated, and a partition coefficient between n-octanol and water at 25°C is greater than 1 for low pH solutions, indicating appreciable portioning to a non-polar phase, but HNCO will be distributed mostly in the aqueous phase at neutral pH. In addition, it was found that the rate of reaction of HNCO with n-octanol was competitive with hydrolysis under physiologically relevant conditions (pH7.4, 37°C), indicating that carbamylation of ROH groups could be significant. Based on these results, research on the carbamylation of other functional groups, and solubility and reaction studies of other isocyanates (e.g. CH3NCO) are warranted. The implications of this multi-phase chemistry for global exposures to wildfire emissions will be discussed.

The taste of soil: chemical investigation of soil, grape and wine in the Sopron wine region (Hungary)

NASA Astrophysics Data System (ADS)

Hofmann, Tomás; Horvàth, Imre; Bidló, András; Hofmann, Eszther

2015-04-01

The taste of soil: chemical investigation of soil, grape and wine in the Sopron wine region (Hungary) The Sopron wine region is one of the most significant and historical wine-producing regions of Hungary. 1800 hectares out of the total area of 4300 hectares of the wine region are used for grape cultivation. Kékfrankos (Blue Frankish) is the most frequent grape variety (60%) nevertheless other varieties are also grown here (including Zweigelt, Merlot, Cabernet Franc, Portugieser and Sauvignon Blanc). In this study preliminary results of the chemical analyses involving soil, grape and wine are presented, which could provide a future basis for a comprehensive terroir research in the wine region. As soil is the premanent home of grapevine, its quality is highly influencing for the growth of the plants and grape berries, and also determines future organoleptic characteristics of the wines. The investigated basic soil parameters included humus content, transition, soil structure, compactness, roots, skeletal percent, color, physical assortment, concretion, soil defects. Laboratory measurements involved the determination of pH, carbonated lime content, humus content, ammonium lactate-acetic acid soluble P and K content, KCl soluble Ca and Mg content, EDTA and DTPA soluble Cu, Fe, Mn and Zn content. Soil samples were also investigated for heavy metal contents using ICP-OES method (Thermo Scientific iCAP 7000 Series). By the use of thermoanalytical measurements (Mettler Toledo TGA/DSC 1 type thermogravimeter, 5°C/min, air atmosphere, 25-1000°C) the mineral composition of the soils was evaluated. Regarding major aroma compounds in grape berries and wine, the concentrations of organic acids (tartaric-, acetic-, succinic-, malic-, lactic acid), methanol, ethanol, glycerine, glucose and fructose were determined by high performance liquid chromatography (Shimadzu LC-20 HPLC equipment with DAD and RID detection). The density, titratable acidity, pH and total extractive content of the wine samples was also determined. With the presentation of the results the possible relationships between individual parameters will be demonstrated. The research is supported by the "Agroclimate-2" (VKSZ_12-1-2013-0034) joint EU-national research project.

Effect of flour processing on the quality characteristics of a soy-based beverage.

PubMed

Arif, Sara; Ahmad, Asif; Masud, Tariq; Khalid, Nauman; Hayat, Imran; Siddique, Farzana; Ali, Muhammad

2012-12-01

Four treatments (roasting, germination, autoclaving and an application of 0.5% EDTA+0.5% sodium hydroxide) were used to reduce the beany flavour of soya beans to produce a soy-based beverage. While germination significantly increased the protein level as compared to the other treatments, the maximum reduction of the beany flavour was achieved by the 0.5% EDTA+0.5% sodium hydroxide application. The soya beans that underwent this treatment were used during the second phase for optimized beverage formulation. During the second phase, a beverage was prepared according to different formulations and analysed for chemical composition and total viable count during a two-month storage period. During storage, the beverage samples exhibited variations in several parameters. The acidity, reducing sugars and total sugars increased, while the ascorbic acid, total soluble solids and pH decreased. Overall, chemical and microbial analyses showed the stability of the product during the storage period.

[Effects of exogenous nitric oxide on physiological characteristics of longan (Dimocarpus longana) seedlings under acid rain stress].

PubMed

Liu, Jian-fu; Wang, Ming-yuan; Yang, Chen; Zhu, Ai-jun

2013-08-01

This paper studied the effects of exogenous nitric oxide donor sodium nitroprusside (SNP) on the chlorophyll content, antioxidant enzyme activities, and osmotic regulation substances of longan (Dimocarpus longana 'Fuyan') seedlings under acid rain (pH 3.0) stress. Under the acid rain stress, the seedling leaf superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and chlorophyll, soluble protein and soluble sugar contents decreased obviously, while the leaf malondialdedyde content had a remarkable increase, suggesting the toxic effect of the acid rain on the seedlings. Exogenous nitric oxide had dual nature on the physiological characteristics of longan seedlings under acid rain stress. Applying 0.1-0.5 mmol x L(-1) of SNP improved the SOD, POD and CAT activities and the chlorophyll, soluble protein and soluble sugar contents significantly, and decreased the malondialdedyde content. Low concentrations SNP reduced the oxidative damage caused by the acid rain stress, and 0.5 mmol x L(-1) of SNP had the best effect. Under the application of 0.5 mmol x L(-1) of SNP, the total chlorophyll, soluble protein, and soluble sugar contents and the SOD, POD and CAT activities increased by 76.0%, 107.0%, 216.1%, 150. 0%, 350.9% and 97.1%, respectively, and the malondialdedyde content decreased by 46.4%. It was suggested that low concentration (0.1-0.5 mmol x L(-1)) SNP could alleviate the toxic effect of acid rain stress on longan seedlings via activating the leaf antioxidant enzyme activities and reducing oxidative stress, while high concentration SNP (1.0 mmol x L(-1)) lowered the mitigation effect.

Fermented inulin hydrolysate by Bifidobacterium breve as cholesterol binder in functional food application

NASA Astrophysics Data System (ADS)

Melanie, Hakiki; Susilowati, Agustine; Maryati, Yati

2017-01-01

Inulin hydrolysate is a result of inulin hydrolysis by inulinase enzyme of Scopulariopsis sp.-CBS1 fungi isolated from dahlia tuber skin in the formation of fructooligosaccharides (FOS) as dietary fiber. Inulin hydrolysate fermented by Bifidobacterium breve has a potential as cholesterol binder in digestive system due to dietary fiber content in inulin. This study was conducted to evaluate the best cholesterol binding capacity by the variation of lactic acid bacteria (LAB) culture concentration of 10%, 20% and 30% (v/v), respectively. Fermentation process were conducted with inulin hydrolysate concentration of 25% (w/v), skim milk 7,5% (w/v) and various LAB culture concentration at 40 °C for 0, 12, 24, 36 and 48 hours. The results showed that the variation of LAB culture concentrations affect the cholesterol binding ability in fermented inulin hydrolysate. The fermentation process with 10% LAB culture concentration at 40°C for 48 hours resulted in the highest cholesterol binding capacity (CBC) of 13,69 mg/g at pH 7and 14,44 mg/g at pH 2 with composition of total acids of 0,787%, soluble dietary fiber of 0,396%, insoluble dietary fiber of 5,47%, total solids of 14,476%, total sugars of 472,484 mg/mL, reducing sugar of 92 mg/mL and total plate count (TPC) of 7,278 log CFU/mL, respectively.

PEROXIDE PROCESS FOR SEPARATION OF RADIOACTIVE MATERIALS

DOEpatents

Seaborg, G.T.; Perlman, I.

1958-09-16

reduced state, from hexavalent uranium. It consists in treating an aqueous solution containing such uranium and plutonium ions with sulfate ions in order to form a soluble uranium sulfate complex and then treating the solution with a soluble thorium compound and a soluble peroxide compound in order to ferm a thorium peroxide carrier precipitate which carries down with it the plutonium peroxide present. During this treatment the pH of the solution must be maintained between 2 and 3.

Reactions of metal ions at surfaces of hydrous iron oxide

USGS Publications Warehouse

Hem, J.D.

1977-01-01

Cu, Ag and Cr concentrations in natural water may be lowered by mild chemical reduction involving ferric hydroxide-ferrous ion redox processes. V and Mo solubilities may be controlled by precipitation of ferrous vanadate or molybdate. Concentrations as low as 10-8.00 or 10-9.00 M are readily attainable for all these metals in oxygen-depleted systems that are relatively rich in Fe. Deposition of manganese oxides such as Mn3O4 can be catalyzed in oxygenated water by coupling to ferrous-ferric redox reactions. Once formed, these oxides may disproportionate, giving Mn4+ oxides. This reaction produces strongly oxidizing conditions at manganese oxide surfaces. The solubility of As is significantly influenced by ferric iron only at low pH. Spinel structures such as chromite or ferrites of Cu, Ni, and Zn, are very stable and if locally developed on ferric hydroxide surfaces could bring about solubilities much below 10-9.00 M for divalent metals near neutral pH. Solubilities calculated from thermodynamic data are shown graphically and compared with observed concentrations in some natural systems. ?? 1977.

Pumpkin (Cucurbita maxima) seed proteins: sequential extraction processing and fraction characterization.

PubMed

Rezig, Leila; Chibani, Farhat; Chouaibi, Moncef; Dalgalarrondo, Michèle; Hessini, Kamel; Guéguen, Jacques; Hamdi, Salem

2013-08-14

Seed proteins extracted from Tunisian pumpkin seeds ( Cucurbita maxima ) were investigated for their solubility properties and sequentially extracted according to the Osborne procedure. The solubility of pumpkin proteins from seed flour was greatly influenced by pH changes and ionic strength, with higher values in the alkaline pH regions. It also depends on the seed defatting solvent. Protein solubility was decreased by using chloroform/methanol (CM) for lipid extraction instead of pentane (P). On the basis of differential solubility fractionation and depending on the defatting method, the alkali extract (AE) was the major fraction (42.1 (P), 22.3% (CM)) compared to the salt extract (8.6 (P), 7.5% (CM)). In salt, alkali, and isopropanol extracts, all essential amino acids with the exceptions of threonine and lysine met the minimum requirements for preschool children (FAO/WHO/UNU). The denaturation temperatures were 96.6 and 93.4 °C for salt and alkali extracts, respectively. Pumpkin protein extracts with unique protein profiles and higher denaturation temperatures could impart novel characteristics when used as food ingredients.

Molecularly designed water soluble, intelligent, nanosize polymeric carriers.

PubMed

Pişkin, Erhan

2004-06-11

Intelligent polymers, also referred as "stimuli-responsive polymers" undergo strong property changes (in shape, surface characteristics, solubility, etc.) when only small changes in their environment (changes in temperature, pH, ionic strength light, electrical and magnetic field, etc.). They have been used in several novel applications, drug delivery systems, tissue engineering scaffolds, bioseparation, biomimetic actuators, etc. The most popular member of these type of polymers is poly(N-isopropylacrylamide) (poly(NIPA)) which exhibits temperature-sensitive character, in which the polymer chains change from water-soluble coils to water-insoluble globules in aqueous solution as temperature increases above the lower critical solution temperature (LCST) of the polymer. Copolymerization of NIPA with acrylic acid (AAc) allows the synthesis of both pH and temperature-responsive copolymers. This paper summarizes some of our related studies in which NIPA and its copolymers were synthesized and used as intelligent carriers in diverse applications.

Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

PubMed Central

Sauerheber, Richard

2013-01-01

The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings. PMID:23840230

Physiologic conditions affect toxicity of ingested industrial fluoride.

PubMed

Sauerheber, Richard

2013-01-01

The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings.

Electroacoustic isoelectric point determinations of bauxite refinery residues: different neutralization techniques and minor mineral effects.

PubMed

Freire, Tiago S S; Clark, Malcolm W; Comarmond, M Josick; Payne, Timothy E; Reichelt-Brushett, Amanda J; Thorogood, Gordon J

2012-08-14

Bauxite refinery residue (BRR) is a highly caustic, iron hydroxide-rich byproduct from alumina production. Some chemical treatments of BRR reduce soluble alkalinity and lower residue pH (to values <10) and generate a modified BRR (MBRR). MBRR has excellent acid neutralizing (ANC) and trace-metal adsorption capacities, making it particularly useful in environmental remediation. However, soluble ANC makes standard acid-base isoelectric point (IEP) determination difficult. Consequently, the IEP of a BRR and five MBRR derivatives (sulfuric acid-, carbon dioxide-, seawater-, a hybrid neutralization, i.e, partial CO(2) neutralization followed by seawater, and an activated-seawater-neutralized MBRR) were determined using electroacoustic techniques. Residues showed three significantly different groups of IEPs (p < 0.05) based around the neutralization used. Where the primary mineral assemblage is effectively unchanged, the IEPs were not significantly different from BRR (pH 6.6-6.9). However, neutralizations generating neoformational minerals (alkalinity precipitation) significantly increased the IEP to pH 8.1, whereas activation (a removal of some primary mineralogy) significantly lowered the IEP to pH 6.2. Moreover, surface charging curves show that surfaces remain in the ±30 mV surface charge instability range, which provides an explanation as to why MBRRs remove trace metals and oxyanions over a broad pH range, often simultaneously. Importantly, this work shows that minor mineral components in complex mineral systems may have a disproportionate effect on the observable bulk IEP. Furthermore, this work shows the appropriateness of electroacoustic techniques in investigating samples with significant soluble mineral components (e.g., ANC).

The solubility of hen egg-white lysozyme

NASA Technical Reports Server (NTRS)

Howard, Sandra B.; Twigg, Pamela J.; Baird, James K.; Meehan, Edward J.

1988-01-01

The equilibrium solubility of chicken egg-white lysozyme in the presence of crystalline solid state was determined as a function of NaCl concentration, pH, and temperature. The solubility curves obtained represent a region of the lysozyme phase diagram. This diagram makes it possible to determine the supersaturation of a given set of conditions or to achieve identical supersaturations by different combinations of parameters. The temperature dependence of the solubility permits the evaluation of Delta-H of crystallization. The data indicate a negative heat of crystallization for the tetragonal crystal form but a positive heat of crystallization for the high-temperature orthorhombic form.

Preparation of dual-stimuli-responsive liposomes using methacrylate-based copolymers with pH and temperature sensitivities for precisely controlled release.

PubMed

Sugimoto, Takumi; Yamazaki, Naoko; Hayashi, Takaaki; Yuba, Eiji; Harada, Atsushi; Kotaka, Aki; Shinde, Chiharu; Kumei, Takayuki; Sumida, Yasushi; Fukushima, Mitsuhiro; Munekata, Yuki; Maruyama, Keiichi; Kono, Kenji

2017-07-01

Dual-signal-sensitive copolymers were synthesized by copolymerization of methoxy diethylene glycol methacrylate, methacrylic acid, and lauroxy tetraethylene glycol methacrylate, which respectively provide temperature sensitivity, pH sensitivity, and anchoring to liposome surfaces. These novel copolymers, with water solubility that differs depending on temperature and pH, are soluble in water under neutral pH and low-temperature conditions, but they become water-insoluble and form aggregates under acidic pH and high-temperature conditions. Liposomes modified with these copolymers exhibited enhanced content release at weakly acidic pH with increasing temperature, although no temperature-dependent content release was observed in neutral conditions. Interaction between the copolymers and the lipid monolayer at the air-water interface revealed that the copolymer chains penetrate more deeply into the monolayer with increasing temperature at acidic pH than at neutral pH, where the penetration of copolymer chains was moderate and temperature-independent at neutral pH. Interaction of the copolymer-modified liposomes with HeLa cells demonstrated that the copolymer-modified liposomes were adsorbed quickly and efficiently onto the cell surface and that they were internalized more gradually than the unmodified liposomes through endocytosis. Furthermore, the copolymer-modified liposomes enhanced the content release in endosomes with increasing temperature, but no such temperature-dependent enhancement of content release was observed for unmodified liposomes. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of sodium lauryl sulfate in dissolution media on dissolution of hard gelatin capsule shells.

PubMed

Zhao, Fang; Malayev, Vyacheslav; Rao, Venkatramana; Hussain, Munir

2004-01-01

Sodium lauryl sulfate (SLS) is a commonly used surfactant in dissolution media for poorly water soluble drugs. However, it has occasionally been observed that SLS negatively impacts the dissolution of drug products formulated in gelatin capsules. This study investigated the effect of SLS on the dissolution of hard gelatin capsule shells. The USP paddle method was used with online UV monitoring at 214 nm (peptide bond). Empty size #0 capsule shells were held to the bottom of the dissolution vessel by magnetic three-prong sinkers. SLS significantly slowed down the dissolution of gelatin shells at pH < 5. Visually, the gelatin shells transformed into some less-soluble precipitate under these conditions. This precipitate was found to contain a higher sulfur content than the gelatin control sample by elemental analysis, indicating that SLS is part of the precipitate. Additionally, the slowdown of capsule shell dissolution was shown to be dependent on the SLS concentration and the ionic strength of the media. SLS interacts with gelatin to form a less-soluble precipitate at pH < 5. The use of SLS in dissolution media at acidic pH should be carefully evaluated for gelatin capsule products.

Silk Spinning in Silkworms and Spiders

PubMed Central

Andersson, Marlene; Johansson, Jan; Rising, Anna

2016-01-01

Spiders and silkworms spin silks that outcompete the toughness of all natural and manmade fibers. Herein, we compare and contrast the spinning of silk in silkworms and spiders, with the aim of identifying features that are important for fiber formation. Although spiders and silkworms are very distantly related, some features of spinning silk seem to be universal. Both spiders and silkworms produce large silk proteins that are highly repetitive and extremely soluble at high pH, likely due to the globular terminal domains that flank an intermediate repetitive region. The silk proteins are produced and stored at a very high concentration in glands, and then transported along a narrowing tube in which they change conformation in response primarily to a pH gradient generated by carbonic anhydrase and proton pumps, as well as to ions and shear forces. The silk proteins thereby convert from random coil and alpha helical soluble conformations to beta sheet fibers. We suggest that factors that need to be optimized for successful production of artificial silk proteins capable of forming tough fibers include protein solubility, pH sensitivity, and preservation of natively folded proteins throughout the purification and initial spinning processes. PMID:27517908

Identification of the solid phase in relation to the solubility of nickel in alluvial soils.

PubMed

Barman, Mandira; Datta, S P; Rattan, R K

2014-09-01

The chemical equillibria between nickel (Ni) ion present in soil solution and solid phases govern the solubility vis-a-vis availability of Ni in soil. Therefore, stability of various Ni containing minerals in relation to pH was studied to identify the probable solid phases, which govern the solubility of Ni in some alluvial soils under intensive cultivation in and around Delhi. Free Ni2+ activity (pNi2+) as estimated by Baker soil test, ranged from 13.1 to 16.2. Highest free Ni2+ activity (pNi2+ = 13.1) was recorded in industrial effluent irrigated soil collected from Sonepat, Haryana. Free Ni2+ activity was 13.6 in soil collected from agricultural lands of Keshopur, receiving irrigation through sewage effluents. Soils receiving irrigation through tube well water showed relatively lower free Ni2+ activity (pNi2+ = 14.6 to 16.2). Ni-ferrite in equilibrium with Fe(OH)3 (amorphous) is likely to control the activity of Ni in two intensively Ni contaminated soil having pH around 8. Free Ni2+ activity is likely to be buffered by exchangeable Ni in soils having neutral pH.

Silk Spinning in Silkworms and Spiders.

PubMed

Andersson, Marlene; Johansson, Jan; Rising, Anna

2016-08-09

Spiders and silkworms spin silks that outcompete the toughness of all natural and manmade fibers. Herein, we compare and contrast the spinning of silk in silkworms and spiders, with the aim of identifying features that are important for fiber formation. Although spiders and silkworms are very distantly related, some features of spinning silk seem to be universal. Both spiders and silkworms produce large silk proteins that are highly repetitive and extremely soluble at high pH, likely due to the globular terminal domains that flank an intermediate repetitive region. The silk proteins are produced and stored at a very high concentration in glands, and then transported along a narrowing tube in which they change conformation in response primarily to a pH gradient generated by carbonic anhydrase and proton pumps, as well as to ions and shear forces. The silk proteins thereby convert from random coil and alpha helical soluble conformations to beta sheet fibers. We suggest that factors that need to be optimized for successful production of artificial silk proteins capable of forming tough fibers include protein solubility, pH sensitivity, and preservation of natively folded proteins throughout the purification and initial spinning processes.

Protein solubilities determined by a rapid technique and modification of that technique to a micro-method

NASA Technical Reports Server (NTRS)

Cacioppo, Elizabeth; Pusey, Marc Lee; Munson, Sibyl

1989-01-01

A simple, rapid method for determination of protein solubilities has been developed which is based upon maximization of the free solution volume to be brought into equilibrium. The tetragonal lysozome solubility diagram has been determined from pH 4.0 to 5.2 (0.1 M sodium acetate), 2-7 percent NaCl, 3-25 C, and portions of the orthorhombic solubility diagram using this technique. Both tetragonal and orthorhombic solubilities were found to increase smoothly with decreasing salt concentration and increasing temperature; no retrograde solubilities were observed. Using column volumes of 75, 300, and 900 microliters, identical tetragonal lysozyme solubility diagrams were obtained. Chymotrypsinogen solubilities have also been determined using this apparatus, being retrograde over the temperature range tested. It is noted that the primary limiting factor in reducing the crystalline volume is the minimum solution sample size needed to accurately quantitate the protein.

Solution-mediated phase transformation of haloperidol mesylate in the presence of sodium lauryl sulfate.

PubMed

Greco, Kristyn; Bogner, Robin

2011-09-01

Forming a salt is a common way to increase the solubility of a poorly soluble compound. However, the solubility enhancement gained by salt formation may be lost due to solution-mediated phase transformation (SMPT) during dissolution. The SMPT of a salt can occur due to a supersaturated solution near the dissolving surface caused by pH or other solution conditions. In addition to changes in pH, surfactants are also known to affect SMPT. In this study, SMPT of a highly soluble salt, haloperidol mesylate, at pH 7 in the presence of a commonly used surfactant, sodium lauryl sulfate (SLS), was investigated. Dissolution experiments were performed using a flow-through dissolution apparatus with solutions containing various concentrations of SLS. Compacts of haloperidol mesylate were observed during dissolution in the flow-through apparatus using a stereomicroscope. Raman microscopy was used to characterize solids. The dissolution of haloperidol mesylate was significantly influenced by the addition of sodium lauryl sulfate. In conditions where SMPT was expected, the addition of SLS at low concentrations (0.1-0.2 mM) reduced the dissolution of haloperidol mesylate. In solutions containing concentrations of SLS above the critical micelle concentration (CMC) (10-15 mM), the dissolution of haloperidol mesylate increased compared to below the CMC. The solids recovered from solubility experiments of haloperidol mesylate indicated that haloperidol free base precipitated at all concentrations of SLS. Above 5 mM of SLS, Raman microscopy suggested a new form, perhaps the estolate salt. The addition of surfactant in solids that undergo solution-mediated phase transformation can add complexity to the dissolution profiles and conversion.

Polypropyleneimine and polyamidoamine dendrimer mediated enhanced solubilization of bortezomib: Comparison and evaluation of mechanistic aspects by thermodynamics and molecular simulations.

PubMed

Chaudhary, Sonam; Gothwal, Avinash; Khan, Iliyas; Srivastava, Shubham; Malik, Ruchi; Gupta, Umesh

2017-03-01

Bortezomib (BTZ) is the first proteasome inhibitor approved by the US-FDA is majorly used for the treatment of newly diagnosed and relapsed multiple myeloma including mantle cell lymphoma. BTZ is hydrophobic in nature and is a major cause for its minimal presence as marketed formulations. The present study reports the design, development and characterization of dendrimer based formulation for the improved solubility and effectivity of bortezomib. The study also equally focuses on the mechanistic elucidation of solubilization by two types of dendrimers i.e. fourth generation of poly (amidoamine) dendrimers (G4-PAMAM-NH 2 ) and fifth generation of poly (propylene) imine dendrimers (G5-PPI-NH 2 ). It was observed that aqueous solubility of BTZ was concentration and pH dependent. At 2mM G5-PPI-NH 2 concentration, the fold increase in bortezomib solubility was 1152.63 times in water, while approximately 3426.69 folds increase in solubility was observed at pH10.0, respectively (p<0.05). The solubility of the drug was increased to a greater extent with G5-PPI-NH 2 dendrimers because it has more hydrophobic interior than G4-PAMAM-NH 2 dendrimers. The release of BTZ from G5-PPI-NH 2 complex was comparatively slower than G4-PAMAM-NH 2 . The thermodynamic treatment of data proved that dendrimer drug complexes were stable at all pH with values of ΔG always negative. The experimental findings were also proven by molecular simulation studies and by calculating RMSD and intermolecular hydrogen bonding through Schrodinger software. It was concluded that PPI dendrimers were able to solubilize the drug more effectively than PAMAM dendrimers through electrostatic interactions. Copyright © 2016 Elsevier B.V. All rights reserved.

Biopharmaceutics classification of puerarin and comparison of perfusion approaches in rats.

PubMed

Li, Hewei; Dong, Ling; Liu, Yang; Wang, Guopeng; Wang, Gang; Qiao, Yanjiang

2014-05-15

The present study was conducted to characterize the biopharmaceutics classification system (BCS) category of puerarin in terms of intrinsic dissolution rate (IDR) and rat intestinal permeability and to investigate the poor intestinal absorption probably related to the drug metabolism in the gut wall of rats. Equilibrium solubility of puerarin was determined in various phosphate buffers and water, and IDR was estimated by measuring the dissolution of a non-disintegrating compact. Intestinal permeability (Peff and Pblood) of puerarin was determined using the technology of in situ single-pass intestinal perfusion (SPIP) and intestinal perfusion with venous sampling (IPVS) in fasted rats. Metabolism of puerarin in intestinal tissue was tested by S9 incubation in vitro. The aqueous solubility of puerarin in phosphate buffers and water was good with a maximum solubility of 7.56 mg/mL at pH 7.4. Obtained IDR values of puerarin were in the range of 0.360-1.088 mg/min/cm(2), with maximum and minimum IDR value of pH 7.4 and pH 4.0, respectively. The Peff was 1.252 × 10(-5)cm/s determined by SPIP and the Pblood was 0.068×10(-5)cm/s by IPVS in jejunum at puerarin 80 μg/mL. The metabolism rate of puerarin determined by the intestinal S9 fraction indicated that the gut wall metabolism of puerarin is one cause of poor absorption. According to the proposed classification of drugs and the results obtained from equilibrium solubility, IDR, Peff and Pblood, it is concluded that puerarin could be categorized IV drug of the BCS based on its low solubility and low intestinal permeability values. Copyright © 2014 Elsevier B.V. All rights reserved.

Tree species affect cation exchange capacity (CEC) and cation binding properties of organic matter in acid forest soils.

PubMed

Gruba, Piotr; Mulder, Jan

2015-04-01

Soil organic matter (SOM) in forest soil is of major importance for cation binding and acid buffering, but its characteristics may differ among soils under different tree species. We investigated acidity, cation exchange properties and Al bonding to SOM in stands of Scots pine, pedunculate oak, Norway spruce, European beech and common hornbeam in southern Poland. The content of total carbon (Ct) was by far the major contributor to total cation exchange capacity (CECt) even in loamy soils and a strong relationship between Ct and CECt was found. The slope of the regression of CECt to Ct increased in the order hornbeam≈oak

Source apportionment of heavy metals and ionic contaminants in rainwater tanks in a subtropical urban area in Australia.

PubMed

Huston, R; Chan, Y C; Chapman, H; Gardner, T; Shaw, G

2012-03-15

Due to prolonged droughts in recent years, the use of rainwater tanks in urban areas has increased in Australia. In order to apportion sources of contribution to heavy metal and ionic contaminants in rainwater tanks in Brisbane, a subtropical urban area in Australia, monthly tank water samples (24 sites, 31 tanks) and concurrent bulk deposition samples (18 sites) were collected during mainly April 2007-March 2008. The samples were analysed for acid-soluble metals, soluble anions, total inorganic carbon and total organic carbon, and characteristics such as total solid and pH. The Positive Matrix Factorisation model, EPA PMF 3.0, was used to apportion sources of contribution to the contaminants. Four source factors were identified for the bulk deposition samples, including 'crustal matter/sea salt', 'car exhausts/road side dust', 'industrial dust' and 'aged sea salt/secondary aerosols'. For the tank water samples, apart from these atmospheric deposition related factors which contributed in total to 65% of the total contaminant concentration on average, another six rainwater collection system related factors were identified, including 'plumbing', 'building material', 'galvanizing', 'roofing', 'steel' and 'lead flashing/paint' (contributing in total to 35% of the total concentration on average). The Australian Drinking Water Guideline for lead was exceeded in 15% of the tank water samples. The collection system related factors, in particular the 'lead flashing/paint' factor, contributed to 79% of the lead in the tank water samples on average. The concentration of lead in tank water was found to vary with various environmental and collection system factors, in particular the presence of lead flashing on the roof. The results also indicated the important role of sludge dynamics inside the tank on the quality of tank water. Copyright © 2011 Elsevier Ltd. All rights reserved.

Solubility of aluminum and silica in Spodic horizons as affected by drying and freezing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simonsson, M.; Berggren, D.; Gustafsson, J.P.

The release of toxic Al{sup 3+} is one of the most serious consequences of anthropogenic soil acidification. Therefore, the mechanisms controlling Al solubility have been a topic of intense research for more than a decade. For convenience, soil samples are often dried before storage and experimental use. However, the literature offers examples of drying that results in changes in pH, solubility of organic matter, and dissolution rates of Al. In this study, the authors examined the solubility of Al and Si in fresh soil and in soil that had been dried or deep-frozen. Five Spodosol B horizon soils were subjectedmore » to batch titrations, where portions of each soil were equilibrated with solutions with varying concentrations of acid or base added. Extractions with acid oxalate and Na pyrophosphate indicated the presence of imogolite-type materials (ITM) in three of the soils. In the other two soils most secondary solid-phase Al was associated with humic substances. Deep-freezing did not significantly change pH nor the concentration of Al or Si as compared with fresh soil. Drying, on the other hand, yielded pH increases of up to 0.3 units at a given addition of acid or base, whereas Al{sup 3+} changed only slightly, implying a higher Al solubility in all of the soils. Furthermore, dissolved silica increased by up to 200% after drying, except in a soil that almost completely lacked oxalate-extractable Si. The authors suggest that drying enhanced the dissolution of ITM by disrupting soil organic matter, thus exposing formerly coated mineral surfaces. In the soil where dissolved Si did not change with drying, it has been demonstrated that Al-humus complexes controlled Al solubility. They suggest that fissures in the organic material caused by drying may have exposed formerly occluded binding sites that had a higher Al saturation than had sites at the surface of humus particles.« less

Heat-Induced Soluble Protein Aggregates from Mixed Pea Globulins and β-Lactoglobulin.

PubMed

Chihi, Mohamed-Lazhar; Mession, Jean-luc; Sok, Nicolas; Saurel, Rémi

2016-04-06

The present work investigates the formation of protein aggregates (85 °C, 60 min incubation) upon heat treatment of β-lactoglobulin (βlg)-pea globulins (Glob) mixtures at pH 7.2 and 5 mM NaCl from laboratory-prepared protein isolates. Various βlg/Glob weight ratios were applied, for a total protein concentration of 2 wt % in admixture. Different analytical methods were used to determine the aggregation behavior of "mixed" aggregates, that is, surface hydrophobicity and also sulfhydryl content, protein interactions by means of SDS-PAGE electrophoresis, and molecule size distribution by DLS and gel filtration. The production of "mixed" thermal aggregates would involve both the formation of new disulfide bonds and noncovalent interactions between the denatured βlg and Glob subunits. The majority of "mixed" soluble aggregates displayed higher molecular weight and smaller diameter than those for Glob heated in isolation. The development of pea-whey protein "mixed" aggregates may help to design new ingredients for the control of innovative food textures.

Thermodynamic origin of instability in hybrid halide perovskites

PubMed Central

Tenuta, E.; Zheng, C.; Rubel, O.

2016-01-01

Degradation of hybrid halide perovskites under the influence of environmental factors impairs future prospects of using these materials as absorbers in solar cells. First principle calculations can be used as a guideline in search of new materials, provided we can rely on their predictive capabilities. We show that the instability of perovskites can be captured using ab initio total energy calculations for reactants and products augmented with additional thermodynamic data to account for finite temperature effects. Calculations suggest that the instability of CH3NH3PbI3 in moist environment is linked to the aqueous solubility of the CH3NH3I salt, thus making other perovskite materials with soluble decomposition products prone to degradation. Properties of NH3OHPbI3, NH3NH2PbI3, PH4PbI3, SbH4PbI3, CsPbBr3, and a new hypothetical SF3PbI3 perovskite are studied in the search for alternative solar cell absorber materials with enhanced chemical stability. PMID:27883032

[Effects of spent mushroom compost on greenhouse cabbage growth under soil salt stress].

PubMed

Wang, Qiu-Ling; Wu, Liang-Huan; Dong, Lan-Xue; Chen, Zai-Ming; Wang, Zhong-Qiang

2011-05-01

A pot experiment was conducted to study the effect of spent mushroom compost (SMC) in alleviating greenhouse soil secondary salinization and cabbage salt stress. With the amendment of SMC, the salinized soil after 60 day cabbage cultivation had a pH value close to 7.0, its organic matter and available phosphorous contents increased significantly, and the increment of total water-soluble salt content reduced, compared with the control. When the amendment amount of SMC was 10 g x kg(-1), the increment of soil water soluble salt content was the least, suggesting that appropriate amendment with SMC could reduce the salt accumulation in greenhouse soil. Amendment with SMC increased the cabbage seed germination rate, plant height, plant fresh mass, chlorophyll SPAD value, and vitamin C content, and decreased the proline content significantly. All the results indicated that SMC could improve the growth environment of greenhouse cabbage, and effectively alleviate the detrimental effect of salt stress.

Effect of high hydrostatic pressure on phenolic compounds, ascorbic acid and antioxidant activity in cashew apple juice

NASA Astrophysics Data System (ADS)

Queiroz, C.; Moreira, C. F. F.; Lavinas, F. C.; Lopes, M. L. M.; Fialho, E.; Valente-Mesquita, V. L.

2010-12-01

The cashew apple is native to Brazil, but there is insufficient information regarding the nutritional properties of this fruit. The objective of this study was to evaluate the impact of high pressure processing (HPP) at room temperature (25 °C) on phenolic compound and ascorbic acid contents and antioxidant capacity of cashew apple juice. This study showed that HPP at 250 or 400 MPa for 3, 5 and 7 min did not change pH, acidity, total soluble solids, ascorbic acid or hydrolysable polyphenol contents. However, juice pressurized for 3 and 5 min showed higher soluble polyphenol contents. Antioxidant capacity, measured by the ferric-reducing antioxidant power method, was not altered by HPP, but when treated at 250 MPa for 3 min, it resulted in an increased value when 2,2-diphenyl-1-picrylhydrazyl was used. These data demonstrate that HPP can be used in the food industry for the generation of products with higher nutritional quality.

Development of β-cyclodextrin-based hydrogel microparticles for solubility enhancement of rosuvastatin: an in vitro and in vivo evaluation

PubMed Central

Sarfraz, Rai Muhammad; Ahmad, Mahmood; Mahmood, Asif; Akram, Muhammad Rouf; Abrar, Asad

2017-01-01

The aim of this study was to enhance the solubility of rosuvastatin (RST) calcium by developing β-cyclodextrin-g-poly(2-acrylamido-2-methylpropane sulfonic acid [AMPS]) hydrogel microparticles through aqueous free-radical polymerization technique. Prepared hydrogel microparticles were characterized for percent entrapment efficiency, solubility studies, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, powder X-ray diffraction, scanning electron microscopy, zeta size and potential, swelling and release studies. Formulations (HS1–HS9) have shown entrapment efficiency between 83.50%±0.30% and 88.50%±0.25%, and optimum release was offered by formulation HS7 at both pH levels, ie, 1.2 (89%) and 7.4 (92%). The majority of microparticles had a particle size of less than 500 µm and zeta potential of −37 mV. Similarly, optimum solubility, ie, 10.66-fold, was determined at pH 6.8 as compared to pure RST calcium, ie, 7.30-fold. In vivo studies on fabricated hydrogel microparticulate system in comparison to pure drug were carried out, and better results regarding pharmacokinetic parameters were seen in the case of hydrogel microparticles. A potential approach for solubility enhancement of RST calcium and other hydrophobic moieties was successfully developed. PMID:29123380

A novel solubility-modulated granules through porosity osmotic pump for controlled carvedilol delivery.

PubMed

Song, Qun-Li; Li, Ping; Li, Yu-Min

2012-01-01

A method for the preparation of porosity osmotic pump granules was obtained by modulating carvedilol solubility with tartaric acid. Controlled porosity of the membrane was accomplished by the use of pore-forming agent in the coating. In this study, carvedilol was chosen as a model drug with an aim to develop a zero-order release system; tartaric acid was used as the solubility promoter; NaCl was used as the osmotic agent; cellulose acetate (CA) was used as the materials of semipermeable membrane; and PEG-400 was used as the pore-forming agent in the semipermeable membrane. The influence of different factors or levels on the in vitro release was studied. In order to simulate the gastrointestinal tract environments, two kinds of pH media (pH 1.5 and 6.8) on drug release were studied in this research, respectively. This porosity osmotic pump was optimized by single factor design experiments, and it was found to deliver carvedilol at a zero-order rate within 12 h and controlled release for 24 h. We drew a conclusion that the solubility-modulated porosity osmotic pump system is simple to prepare and might be used for the preparation of osmotic pump system of other poorly water-soluble drugs with alkaline or acid groups.

Development of novel sibutramine base-loaded solid dispersion with gelatin and HPMC: physicochemical characterization and pharmacokinetics in beagle dogs.

PubMed

Lim, Hyun-Tae; Balakrishnan, Prabagar; Oh, Dong Hoon; Joe, Kwan Hyung; Kim, Young Ran; Hwang, Doo Hyung; Lee, Yong-Bok; Yong, Chul Soon; Choi, Han-Gon

2010-09-15

To develop a novel sibutramine base-loaded solid dispersion with enhanced solubility and bioavailability, various solid dispersions were prepared using a spray drying technique with hydrophilic polymers such as gelatin, HPMC and citric acid. Their solubility, thermal characteristics and crystallinity were investigated. The dissolution and pharmacokinetics of the sibutramine base-loaded solid dispersion were then compared with a sibutramine hydrochloride monohydrate-loaded commercial product (Reductil). The solid dispersions prepared with gelatin gave higher drug solubility than those prepared without gelatin, irrespective of the amount of polymer. The sibutramine base-loaded solid dispersions containing hydrophilic polymer and citric acid showed higher drug solubility compared to sibutramine base and sibutramine hydrochloride monohydrate. Among the formulations tested, the solid dispersion composed of sibutramine base/gelatin/HPMC/citric acid at the weight ratio of 1/0.8/0.2/0.5 gave the highest solubility of 5.03+/-0.24 mg/ml. Our DSC and powder X-ray diffraction results showed that the drug was present in an altered amorphous form in this solid dispersion. The difference factor (f(1)) values between solid dispersion and commercial product were 2.82, 6.65 and 6.31 at pH 1.2, 4.0 and 6.8, respectively. Furthermore, they had the similarity factor (f(2)) value of 65.68, 53.43 and 58.97 at pH 1.2, 4.0 and 6.8, respectively. Our results suggested that the solid dispersion and commercial product produced a similar correlation of dissolution profiles at all pH ranges. The AUC, C(max) and T(max) of the parent drug and metabolite I and II from the solid dispersion were not significantly different from those of the commercial product, suggesting that the solid dispersion might be bioequivalent to the commercial product in beagle dogs. Thus, the sibutramine base-loaded solid dispersion prepared with gelatin, HPMC and citric acid is a promising candidate for improving the solubility and bioavailability of the poorly water-soluble sibutramine base. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

pH-sensitive polymeric nanoparticles to improve oral bioavailability of peptide/protein drugs and poorly water-soluble drugs.

PubMed

Wang, Xue-Qing; Zhang, Qiang

2012-10-01

pH-sensitive polymeric nanoparticles are promising for oral drug delivery, especially for peptide/protein drugs and poorly water-soluble medicines. This review describes current status of pH-sensitive polymeric nanoparticles for oral drug delivery and introduces the mechanisms of drug release from them as well as possible reasons for absorption improvement, with emphasis on our contribution to this field. pH-sensitive polymeric nanoparticles are prepared mainly with polyanions, polycations, their mixtures or cross-linked polymers. The mechanisms of drug release are the result of carriers' dissolution, swelling or both of them at specific pH. The possible reasons for improvement of oral bioavailability include the following: improve drug stability, enhance mucoadhesion, prolong resident time in GI tract, ameliorate intestinal permeability and increase saturation solubility and dissolution rate for poorly water-soluble drugs. As for the advantages of pH-sensitive nanoparticles over conventional nanoparticles, we conclude that (1) most carriers used are enteric-coating materials and their safety has been approved. (2) The rapid dissolution or swelling of carriers at specific pH results in quick drug release and high drug concentration gradient, which is helpful for absorption. (3) At the specific pH carriers dissolve or swell, and the bioadhesion of carriers to mucosa becomes high because nanoparticles turn from solid to gel, which can facilitate drug absorption. Copyright © 2012 Elsevier B.V. All rights reserved.

Soybean glycinin subunits: Characterization of physicochemical and adhesion properties.

PubMed

Mo, Xiaoqun; Zhong, Zhikai; Wang, Donghai; Sun, Xiuzhi

2006-10-04

Soybean proteins have shown great potential for applications as renewable and environmentally friendly adhesives. The objective of this work was to study physicochemical and adhesion properties of soy glycinin subunits. Soybean glycinin was extracted from soybean flour and then fractionated into acidic and basic subunits with an estimated purity of 90 and 85%, respectively. Amino acid composition of glycinin subunits was determined. The high hydrophobic amino acid content is a major contributor to the solubility behavior and water resistance of the basic subunits. Acidic subunits and glycinin had similar solubility profiles, showing more than 80% solubility at pH 2.0-4.0 or 6.5-12.0, whereas basic subunits had considerably lower solubility with the minimum at pH 4.5-8.0. Thermal analysis using a differential scanning calorimeter suggested that basic subunits form new oligomeric structures with higher thermal stability than glycinin but no highly ordered structures present in isolated acidic subunits. The wet strength of basic subunits was 160% more than that of acidic subunits prepared at their respective isoelectric points (pI) and cured at 130 degrees C. Both pH and the curing temperature significantly affected adhesive performance. High-adhesion water resistance was usually observed for adhesives from protein prepared at their pI values and cured at elevated temperatures. Basic subunits are responsible for the water resistance of glycinin and are a good starting material for the development of water-resistant adhesives.

Biochemical characterization of soluble proteins in pecan [Carya illinoinensis (Wangenh.) K. Koch].

PubMed

Venkatachalam, Mahesh; Roux, Kenneth H; Sathe, Shridhar K

2008-09-10

Pecans (cv. Desirable) contained approximately 10% protein on a dry weight basis. The minimum nitrogen solubility (5.9-7.5%) at 0.25-0.75 M trichloroacetic acid represented the nonprotein nitrogen. Among the solvents assessed for protein solubilization, 0.1 M NaOH was the most effective, while borate saline buffer (pH 8.45) was judged to be optimal for protein solubilization. The protein solubility was minimal in the pH range of 3-7 and significantly increased on either side of this pH range. Increasing the NaCl concentration from 0 to 4 M significantly improved ( approximately 8-fold increase) protein solubilization. Following Osborne protein fractionation, the alkali-soluble glutelin fraction (60.1%) accounted for a major portion of pecan proteins followed by globulin (31.5%), prolamin (3.4%), and albumin (1.5%), respectively. The majority of pecan polypeptides were in the molecular mass range of 12-66 kDa and in the pI range of 4.0-8.3. The pecan globulin fraction was characterized by the presence of several glycoprotein polypeptides. Lysine was the first limiting essential amino acid in the defatted flour, globulin, prolamin, and alkaline glutelin fractions. Leucine and tryptophan were the first limiting essential amino acids in albumin and acid glutelin fractions, respectively. Rabbit polyclonal antibodies detected a range of pecan polypeptides in the 12-60 kDa range, of which the globulin fraction contained the most reactive polypeptides.

Chemical interactions of aluminum with aqueous silica at 25 degrees Celsius

USGS Publications Warehouse

Hem, John David; Roberson, C.E.; Lind, Carol J.; Polxer, W.L.

1973-01-01

Solutions containing from 10 -5 to 10 -2 moles per liter of aluminum and dissolved silica in various ratios were aged at pH levels between 4 and 10 at 25?C. A colloidal amorphous product having the composition of halloysite was produced in most solutions. It had a consistent and reversible equilibrium solubility equivalent to a standard free energy of formation of -8974 ? 1.0 kcal per mole for the formula A12Si2O5(OH)4. Some aging times were longer than 4 years, but most solutions gave consistent solubilities after only a few months of aging. Where silica concentrations were below about 10 -4 molar, microcrystalline gibbsite was formed below pH 6.0 and crystalline bayerite above pH 7.0, but only after much longer aging than was required for crystallization in silica-free solutions. Electron micrographs and diffraction patterns of the synthesized material indicate some crystallinity in the aluminosilicate, but no X-ray diffraction patterns could be obtained even in the material aged 4 years. Solubility relationships for solutions containing fluoride as well as silica and aluminum are explainable by using cryolite stabilities determined in previous work. Aluminum contents of 51 samples of water analyzed for other purposes are in reasonable agreement with the assumption of equilibrium with amorphous clay mineral species similar to the material synthesized in this work. Solubility calculations are summarized graphically for solutions of ionic strength of 0.01 and 0.10.

Geochemical conditions and the occurrence of selected trace elements in groundwater basins used for public drinking-water supply, Desert and Basin and Range hydrogeologic provinces, 2006-11: California GAMA Priority Basin Project

USGS Publications Warehouse

Wright, Michael T.; Fram, Miranda S.; Belitz, Kenneth

2015-01-01

Concentrations of strontium, which exists primarily in a cationic form (Sr2+), were not significantly correlated with either groundwater age or pH. Strontium concentrations showed a strong positive correlation with total dissolved solids (TDS). Dissolved constituents, such as Sr, that interact with mineral surfaces through outer-sphere complexation become increasingly soluble with increasing TDS concentrations of groundwater. Boron concentrations also showed a significant positive correlation with TDS, indicating the B may interact to a large degree with mineral surfaces through outer-sphere complexation.

Students’ misconceptions on solubility equilibrium

NASA Astrophysics Data System (ADS)

Setiowati, H.; Utomo, S. B.; Ashadi

2018-05-01

This study investigated the students’ misconceptions of the solubility equilibrium. The participants of the study consisted of 164 students who were in the science class of second year high school. Instrument used is two-tier diagnostic test consisting of 15 items. Responses were marked and coded into four categories: understanding, misconception, understand little without misconception, and not understanding. Semi-structured interviews were carried out with 45 students according to their written responses which reflected different perspectives, to obtain a more elaborated source of data. Data collected from multiple methods were analyzed qualitatively and quantitatively. Based on the data analysis showed that the students misconceptions in all areas in solubility equilibrium. They had more misconceptions such as in the relation of solubility and solubility product, common-ion effect and pH in solubility, and precipitation concept.

Soil organic matter-hydrogen peroxide dynamics in the treatment of contaminated soils and groundwater using catalyzed H2O2 propagations (modified Fenton's reagent).

PubMed

Bissey, Lauren L; Smith, Jeffrey L; Watts, Richard J

2006-07-01

The interactions between catalyzed H(2)O(2) propagations (CHP-i.e. modified Fenton's reagent) and soil organic matter (SOM) during the treatment of contaminated soils and groundwater was studied in a well-characterized surface soil. The fate of two fractions of SOM, particulate organic matter (POM) and nonparticulate organic matter (NPOM), during CHP reactions was evaluated using concentrations of hydrogen peroxide from 0.5 to 3M catalyzed by soluble iron (III), an iron (III)-ethylenediamine tetraacetic acid (EDTA) chelate, or naturally-occurring soil minerals. The destruction of total SOM in CHP systems was directly proportional to the hydrogen peroxide dosage, and was significantly greater at pH 3 than at neutral pH; furthermore, SOM destruction occurred predominantly in the NPOM fraction. At pH 3, SOM did not affect hydrogen peroxide decomposition rates or hydroxyl radical activity in CHP reactions. However, at neutral pH, increasing the mass of SOM decreased the hydrogen peroxide decomposition rate and increased the rate of hydroxyl radical generation in CHP systems. These results show that, while CHP reactions destroy some of the organic carbon pools, SOM does not have a significant effect on the CHP treatment of soils and groundwater.

Serpentinite and the dawn of life

PubMed Central

Sleep, Norman H.; Bird, Dennis K.; Pope, Emily C.

2011-01-01

Submarine hydrothermal vents above serpentinite produce chemical potential gradients of aqueous and ionic hydrogen, thus providing a very attractive venue for the origin of life. This environment was most favourable before Earth's massive CO2 atmosphere was subducted into the mantle, which occurred tens to approximately 100 Myr after the moon-forming impact; thermophile to clement conditions persisted for several million years while atmospheric pCO2 dropped from approximately 25 bar to below 1 bar. The ocean was weakly acid (pH ∼ 6), and a large pH gradient existed for nascent life with pH 9–11 fluids venting from serpentinite on the seafloor. Total CO2 in water was significant so the vent environment was not carbon limited. Biologically important phosphate and Fe(II) were somewhat soluble during this period, which occurred well before the earliest record of preserved surface rocks approximately 3.8 billion years ago (Ga) when photosynthetic life teemed on the Earth and the oceanic pH was the modern value of approximately 8. Serpentinite existed by 3.9 Ga, but older rocks that might retain evidence of its presence have not been found. Earth's sequesters extensive evidence of Archaean and younger subducted biological material, but has yet to be exploited for the Hadean record. PMID:21930576

Quantitative models for predicting adsorption of oxytetracycline, ciprofloxacin and sulfamerazine to swine manures with contrasting properties.

PubMed

Cheng, Dengmiao; Feng, Yao; Liu, Yuanwang; Li, Jinpeng; Xue, Jianming; Li, Zhaojun

2018-09-01

Understanding antibiotic adsorption in livestock manures is crucial to assess the fate and risk of antibiotics in the environment. In this study, three quantitative models developed with swine manure-water distribution coefficients (LgK d ) for oxytetracycline (OTC), ciprofloxacin (CIP) and sulfamerazine (SM1) in swine manures. Physicochemical parameters (n=12) of the swine manure were used as independent variables using partial least-squares (PLSs) analysis. The cumulative cross-validated regression coefficients (Q 2 cum ) values, standard deviations (SDs) and external validation coefficient (Q 2 ext ) ranged from 0.761 to 0.868, 0.027 to 0.064, and 0.743 to 0.827 for the three models; as such, internal and external predictability of the models were strong. The pH, soluble organic carbon (SOC) and nitrogen (SON), and Ca were important explanatory variables for the OTC-Model, pH, SOC, and SON for the CIP-model, and pH, total organic nitrogen (TON), and SOC for the SM1-model. The high VIPs (variable importance in the projections) of pH (1.178-1.396), SOC (0.968-1.034), and SON (0.822 and 0.865) established these physicochemical parameters as likely being dominant (associatively) in affecting transport of antibiotics in swine manures. Copyright © 2018 Elsevier B.V. All rights reserved.

Start-up of a pilot-scale anaerobic fixed film reactor at low temperature treating slaughterhouse wastewater.

PubMed

del Pozo, R; Diez, V; Salazar, G

2002-01-01

A pilot-scale anaerobic fixed film reactor (AFFR) with vertically arranged PVC tubes as biomass carrier, treating poultry slaughterhouse wastewater was started-up in 74 days at temperatures between 20-24 degrees C. The start-up process consisted of a long acclimatization phase followed by a low loaded growth phase, a gradual increase of OLR upto 9.2 kg COD/m3d, and a final maturation phase at moderated loads of 2.7 kg COD/m3d at which total COD removal efficiencies of 57% were achieved. Alkalinity ratio IA:PA was found to be the best control parameter to avoid VFA accumulation. OLR increase based on pH control was not satisfactory because changes in CO2 solubility caused daily by temperature and flow variations led to pH oscillations of 0.2 units. The low wastewater alkalinity, 260 mg/l CaCO3 was insufficient to buffer the pH system, therefore the pH decrease associated with the VFA accumulation was not easily detected and could not be used as a way of OLR control. Organic matter removal took place by accumulation and biodegradation processes. Limitation in the reactor hydrodynamics and particulate fraction hydrolysis was detected at high flow rates.

Short communication: Serum composition of milk subjected to re-equilibration by dialysis at different temperatures, after pH adjustments.

PubMed

Zhao, Zhengtao; Corredig, Milena

2016-04-01

The objective of this work was to investigate the properties of casein micelles after pH adjustment and their re-equilibration to the original pH and serum composition. Re-equilibration was carried out by dialyzing against skim milk at 2 different temperatures (4 or 22 °C). Turbidity, the average radius of the casein micelles, and the composition of the soluble phase were measured at different pH values, ranging between 5.5 and 8. Acidification led to the solubilization of colloidal calcium phosphate and decrease of the average radius of the micelles. With re-equilibration, casein dissociation occurred. In milk with pH values greater than 6.0, the average radius was recovered after re-equilibration. At pH values greater than neutral, an increase of the radius of casein micelles and increased dissociation of the casein were found. After re-equilibration, the radius of micelles and soluble protein in the serum decreased. The results were not affected by the temperature of re-equilibration. The changes to the calcium phosphate equilibrium and the dissociation of the micelles will have important consequences to the functionality of casein micelles. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Physico-chemical and antioxidant properties of four mango (Mangifera indica L.) cultivars in China.

PubMed

Liu, Feng-Xia; Fu, Shu-Fang; Bi, Xiu-Fang; Chen, Fang; Liao, Xiao-Jun; Hu, Xiao-Song; Wu, Ji-Hong

2013-05-01

Four principal mango cultivars (Tainong No.1, Irwin, JinHwang and Keitt) grown in southern China were selected, and their physico-chemical and antioxidant properties were characterized and compared. Of all the four cultivars, Tainong No.1 had highest content of total phenols, ρ-coumaric acid, sinapic acid, quercetin, titratable acidity, citric acid, malic acid, fructose, higher antioxidant activities (DPPH, FRAP) and L(*), lower pH, PPO activity and individual weight. Keitt mangoes showed significantly (p<0.05) higher contents of β-carotene, ρ-hydroxybenzoic acid, sucrose, total sugar, total soluble solid, catechin, succinic acid and higher PPO activity. JinHwang mangoes exhibited significantly (p<0.05) higher individual weight and PPO activity, but had lower content of total phenols, β-carotene and lower antioxidant activity. Principal component analysis (PCA) allowed the four mango cultivars to be differentiated clearly based on all these physico-chemical and antioxidant properties determined in the study. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of pH buffering capacity and sources of dietary sulfur on rumen fermentation, sulfide production, methane production, sulfate reducing bacteria, and total Archaea in in vitro rumen cultures.

PubMed

Wu, Hao; Meng, Qingxiang; Yu, Zhongtang

2015-06-01

The effects of three types of dietary sulfur on in vitro fermentation characteristics, sulfide production, methane production, and microbial populations at two different buffer capacities were examined using in vitro rumen cultures. Addition of dry distilled grain with soluble (DDGS) generally decreased total gas production, degradation of dry matter and neutral detergent fiber, and concentration of total volatile fatty acids, while increasing ammonia concentration. High buffering capacity alleviated these adverse effects on fermentation. Increased sulfur content resulted in decreased methane emission, but total Archaea population was not changed significantly. The population of sulfate reducing bacteria was increased in a sulfur type-dependent manner. These results suggest that types of dietary sulfur and buffering capacity can affect rumen fermentation and sulfide production. Diet buffering capacity, and probably alkalinity, may be increased to alleviate some of the adverse effects associated with feeding DDGS at high levels. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mineralogical study of stream waters and efflorescent salts in Sierra Minera, SE Spain

NASA Astrophysics Data System (ADS)

Pérez-Sirvent, Carmen; Garcia-Lorenzo, Maria luz; Martinez-Sanchez, Maria Jose; Hernandez, Carmen; Hernandez-Cordoba, Manuel

2015-04-01

Trace elements contained in the residues from mining and metallurgical operations are often dispersed by wind and/or water after their disposal. These areas have severe erosion problems caused by water run-off in which soil and mine spoil texture, landscape topography and regional and microclimate play an important role. Water pollution by dissolved metals in mining areas has mainly been associated with the oxidation of sulphide-bearing minerals exposed to weathering conditions, resulting in low quality effluents of acidic pH and containing a high level of dissolved metals. The studied area, Sierra Minera, is close to the mining region of La Unión (Murcia, SE Spain). This area constituted an important mining centre for more than 2500 years, ceasing activity in 1991. The ore deposits of this zone have iron, lead and zinc as the main metal components. Studied area showed a lot of contaminations sources, formed by mining steriles, waste piles and foundry residues. As a consequence of the long period of mining activity, large volumes of wastes were generated during the mineral concentration and smelting processes. Historically, these wastes were dumped into watercourses, filling riverbeds and contaminating their surroundings. 40 sediment samples were collected from the area affected by mining exploitations, and at increasing distances from the contamination sources in 4 zones In addition, 36 surficial water samples were collected after a rain episode The Zn and Fe content was determined by flame atomic absorption spectrometry (FAAS). The Pb and Cd content was determined by electrothermal atomization atomic absorption spectrometry (ETAAS). The As content was measured by atomic fluorescence spectrometry using an automated continuous flow hydride generation spectrometer and Al content was determined by ICP-MS. Mineralogical composition of the samples was made by X Ray Diffraction (XRD) analysis using Cu-Kα radiation with a PW3040 Philips Diffractometer. Zone A: Water sample collected in A5 is strongly influenced by a tailing dump, and showed high trace element contents. In addition, is influenced by the sea water and then showed high bromide, chloride, sodium and magnesium content, together with a basic pH.The DRX results of evaporate water showed that halite, hexahydrite and gypsum are present: halite corroborates the sea influence and gypsum and hexahydrite the importance of soluble sulphates. A9 water showed acid pH and high trace elements content; is influenced by the tailing dump and also by waters from El Beal gully watercourse, transporting materials from Sierra Minera Waters affected by secondary contamination are influenced by mining wastes, the sea water and also are affected by agricultural activities (nitrate content). These waters have been mixed with carbonate materials, present in the zone increasing the pH. Some elements have precipitated, such as Cu and Pb, while Cd, Zn and As are soluble. The DRX analysis in the evaporate if A14 showed that halite and gypsum are present: halite confirms the seawater influence and gypsum the relationship between calcium and sulphates A2 and A6 waters are affected by tertiary contamination and showed basic pH, soluble carbonates and lower trace element content. Only Zn, Cd and Al are present. Zone B: All waters are strongly affected by mining activities and showed: acid pH, high trace element content and high content of soluble sulphates. The evaporate of B8 and B12 showed the presence of soluble sulphates: gypsum, halite, bianchite, paracoquimbite, halotrichite and siderotil in B8; gypsum, bianchite, paracoquimbite and coquimbite in B12; gypsum, hexahydrite, carnalite, bianchite, copiapite and sideroti in B10 and polihalite, gypsum, bianchite, coquimbite and paracoquimbite in B14. All the sampling points collected in Zone C are affected by primary contamination, because there are a lot of tailing dumps and sampling points are located close to them. C1 showed high trace element content because is a reception point of a lot of tailing dumps. Water samples from C3 to C8 also had acid pH and high trace element content, particularly As (remains soluble) and Zn and Cd (high mobility). In addition, they showed high soluble sulphates. C2 water showed neutral pH, soluble carbonate and low trace element content because is influenced by a stabilised tailing dump. However, the As remains soluble. Zone D: All waters collected in this zone showed acid pH and high trace element content, mainly Zn, Cd and As. Some differences were found from the high and the low part: samples located in the lower part (D2-D7) showed higher As content while Zn is higher in the high part (D8-D13) The DRX analysis in evaporates suggest that in D4 copiapite, coquimbite, gypsum, bianchite and ferrohexahydrite are formed and in D11 gypsum, bianchite, halotrichite and siderotil. D1 is affected by secondary contamination, which showed higher pH (still acid) and lower content in soluble salts and trace elements.

pH Neutralization of Aqueous Bio-Oil from Switchgrass Intermediate Pyrolysis Using Process Intensification Devices

DOE PAGES

Park, Lydia Kyoung-Eun; Ren, Shoujie; Yiacoumi, Sotira; ...

2017-07-20

Despite the potential carbon-neutrality of switchgrass bio-oil, its high acidity and diverse chemical composition limit its utilization. The objectives of this research are to investigate pH neutralization of bio-oil by adding various alkali solutions in a batch system and then perform neutralization using process intensification devices, including a static mixer and a centrifugal contactor. The results indicate that sodium hydroxide and potassium hydroxide are more appropriate bases for pH neutralization of bio-oil than calcium hydroxide due to the limited solubility of calcium hydroxide in aqueous bio-oil. Mass and total acid number (TAN) balances were performed for both batch and continuous-flowmore » systems. Upon pH neutralization of bio-oil, the TAN values of the system increased after accounting the addition of alkali solution. A bio-oil heating experiment showed that the heat generated during pH neutralization did not cause a significant increase in the acidity of bio-oil. The formation of phenolic compounds during neutralization was initially suspected of increasing the system’s overall TAN value because some of these compounds (e.g., vanillic acid) act as polyprotic acids and have a stronger influence on the TAN value than monoprotic acids (e.g., acetic acid). The amount of phenolics in separated bio-oil phases, however, did not change significantly after pH neutralization. In conclusion, process intensification devices provided sufficient mixing and separation of the organic and aqueous phases, suggesting a scale-up route for the bio-oil pH neutralization process.« less

pH Neutralization of Aqueous Bio-Oil from Switchgrass Intermediate Pyrolysis Using Process Intensification Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Lydia Kyoung-Eun; Ren, Shoujie; Yiacoumi, Sotira

Despite the potential carbon-neutrality of switchgrass bio-oil, its high acidity and diverse chemical composition limit its utilization. The objectives of this research are to investigate pH neutralization of bio-oil by adding various alkali solutions in a batch system and then perform neutralization using process intensification devices, including a static mixer and a centrifugal contactor. The results indicate that sodium hydroxide and potassium hydroxide are more appropriate bases for pH neutralization of bio-oil than calcium hydroxide due to the limited solubility of calcium hydroxide in aqueous bio-oil. Mass and total acid number (TAN) balances were performed for both batch and continuous-flowmore » systems. Upon pH neutralization of bio-oil, the TAN values of the system increased after accounting the addition of alkali solution. A bio-oil heating experiment showed that the heat generated during pH neutralization did not cause a significant increase in the acidity of bio-oil. The formation of phenolic compounds during neutralization was initially suspected of increasing the system’s overall TAN value because some of these compounds (e.g., vanillic acid) act as polyprotic acids and have a stronger influence on the TAN value than monoprotic acids (e.g., acetic acid). The amount of phenolics in separated bio-oil phases, however, did not change significantly after pH neutralization. In conclusion, process intensification devices provided sufficient mixing and separation of the organic and aqueous phases, suggesting a scale-up route for the bio-oil pH neutralization process.« less

Comparative study of the functional properties of lupin, green pea, fava bean, hemp, and buckwheat flours as affected by pH

PubMed Central

Raikos, Vassilios; Neacsu, Madalina; Russell, Wendy; Duthie, Garry

2014-01-01

The demand for products of high nutritional value from sustainable sources is growing rapidly in the global food market. In this study, the effect of pH on the functional properties of lupin, green pea, fava bean, hemp, and buckwheat flours was investigated and compared with wheat flour. Functional properties included solubility, emulsifying and foaming properties, gelling ability, and water holding capacity (WHC). All flours had minimal solubility at pH 4 and their corresponding values increased with increasing pH. Emulsifying properties were improved at pH 10 for all samples and emulsion stability showed a similar trend. Increasing pH in the range 4–10 enhanced the foaming properties of the flours, particularly buckwheat and hemp. Wheat, green pea, buckwheat, and fava bean were more capable of forming firm gels compared with lupin and hemp, as indicated by least gelling concentrations (LGCs). The ranking of the water binding properties of the different types of flours were lupin>hemp>fava bean>buckwheat>green pea>wheat. Results indicate that underutilized flours from sustainable plant sources could be exploited by the food industry as functional food ingredients or as replacements of wheat flour for various food applications. Depending on the application, flour functionality may be effectively tailored by pH adjustment. PMID:25493199

Nanoparticle titanium dioxide aqueous interfacial energy can be modified to control phase stability, coarsening, and morphology

NASA Astrophysics Data System (ADS)

Finnegan, Michael Patrick

The effect of solution chemistry on the phase stability, coarsening kinetics and morphology of titanium dioxide (TiO2) nanoparticles is investigated in order to attain efficient production pathways to desired nano-structures with optimal properties. To obtain sample, TiO2 was synthesized via hydrolysis of titanium isopropoxide producing an 85% anatase/15% brookite mixture. The titania was hydrothermally heated in an array of temperatures and pH values for various times. There are distinct phase stability fields for nanoscale titania based on pH alone due to slight interface charging behavior differences among the polymorphs. The mixture transforms to rutile below the pH of zero point of charge (ZPC) and remains anatase above the ZPC. This phenomenon is partially reversible. The solution chemistry also dictates the hydrothermal coarsening mechanism of the anatase polymorph. Ostwald ripening (OR) takes place in basic pH where titania solubility is elevated relative to neutral pH where lower solubility prevents rapid OR but allows for coarsening via oriented attachment (OA) of nanoparticles. This OA event can alter the symmetry of anatase causing unexpected and perhaps technically useful morphologies such as straight and curved nanorods during coarsening.

Study of antioxidant properties of a water-soluble Vitamin E derivative-tocopherol monoglucoside (TMG) by differential pulse voltammetry.

PubMed

Korotkova, E I; Avramchik, O A; Kagiya, T V; Karbainov, Y A; Tcherdyntseva, N V

2004-06-17

Study of antioxidant properties of tocopherol monoglucoside (TMG), a water-soluble Vitamin E derivative, by differential pulse voltammetry has been carried out in this work. The pH influence on the antioxidant properties of TMG has been also investigated. It was observed that the antioxidant activity of TMG is greater at 6.90

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.

Particle water and pH in the eastern Mediterranean: source variability and implications for nutrient availability

NASA Astrophysics Data System (ADS)

Bougiatioti, Aikaterini; Nikolaou, Panayiota; Stavroulas, Iasonas; Kouvarakis, Giorgos; Weber, Rodney; Nenes, Athanasios; Kanakidou, Maria; Mihalopoulos, Nikolaos

2016-04-01

Particle water (liquid water content, LWC) and aerosol pH are important parameters of the aerosol phase, affecting heterogeneous chemistry and bioavailability of nutrients that profoundly impact cloud formation, atmospheric composition, and atmospheric fluxes of nutrients to ecosystems. Few measurements of in situ LWC and pH, however, exist in the published literature. Using concurrent measurements of aerosol chemical composition, cloud condensation nuclei activity, and tandem light scattering coefficients, the particle water mass concentrations associated with the aerosol inorganic (Winorg) and organic (Worg) components are determined for measurements conducted at the Finokalia atmospheric observation station in the eastern Mediterranean between June and November 2012. These data are interpreted using the ISORROPIA-II thermodynamic model to predict the pH of aerosols originating from the various sources that influence air quality in the region. On average, closure between predicted aerosol water and that determined by comparison of ambient with dry light scattering coefficients was achieved to within 8 % (slope = 0.92, R2 = 0.8, n = 5201 points). Based on the scattering measurements, a parameterization is also derived, capable of reproducing the hygroscopic growth factor (f(RH)) within 15 % of the measured values. The highest aerosol water concentrations are observed during nighttime, when relative humidity is highest and the collapse of the boundary layer increases the aerosol concentration. A significant diurnal variability is found for Worg with morning and afternoon average mass concentrations being 10-15 times lower than nighttime concentrations, thus rendering Winorg the main form of particle water during daytime. The average value of total aerosol water was 2.19 ± 1.75 µg m-3, contributing on average up to 33 % of the total submicron mass concentration. Average aerosol water associated with organics, Worg, was equal to 0.56 ± 0.37 µg m-3; thus, organics contributed about 27.5 % to the total aerosol water, mostly during early morning, late evening, and nighttime hours.

The aerosol was found to be highly acidic with calculated aerosol pH varying from 0.5 to 2.8 throughout the study period. Biomass burning aerosol presented the highest values of pH in the submicron fraction and the lowest values in total water mass concentration. The low pH values observed in the submicron mode and independently of air mass origin could increase nutrient availability and especially P solubility, which is the nutrient limiting sea water productivity of the eastern Mediterranean.

Particle water and pH in the Eastern Mediterranean: sources variability and implications for nutrients availability

NASA Astrophysics Data System (ADS)

Nikolaou, P.; Bougiatioti, A.; Stavroulas, I.; Kouvarakis, G.; Nenes, A.; Weber, R.; Kanakidou, M.; Mihalopoulos, N.

2015-10-01

Particle water (LWC) and aerosol pH drive the aerosol phase, heterogeneous chemistry and bioavailability of nutrients that profoundly impact cloud formation, atmospheric composition and atmospheric fluxes of nutrients to ecosystems. Few measurements of in-situ LWC and pH however exist in the published literature. Using concurrent measurements of aerosol chemical composition, cloud condensation nuclei activity and tandem light scattering coefficients, the particle water mass concentrations associated with the aerosol inorganic (Winorg) and organic (Worg) components are determined for measurements conducted at the Finokalia atmospheric observation station in the eastern Mediterranean between August and November 2012. These data are interpreted using the ISORROPIA-II thermodynamic model to predict pH of aerosols originating from the various sources that influence air quality in the region. On average, closure between predicted aerosol water and that determined by comparison of ambient with dry light scattering coefficients was achieved to within 8 % (slope = 0.92, R2 = 0.8, n = 5201 points). Based on the scattering measurements a parameterization is also derived, capable of reproducing the hygroscopic growth factor (f(RH)) within 15 % of the measured values. The highest aerosol water concentrations are observed during nighttime, when relative humidity is highest and the collapse of the boundary layer increases the aerosol concentration. A significant diurnal variability is found for Worg with morning and afternoon average mass concentrations being 10-15 times lower than nighttime concentrations, thus rendering Winorg the main form of particle water during daytime. The average value of total aerosol water was 2.19 ± 1.75 μg m-3, contributing on average up to 33 % of the total submicron mass concentration. Average aerosol water associated with organics, Worg, was equal to 0.56 ± 0.37 μg m-3, thus organics contributed about 27.5 % to the total aerosol water, mostly during early morning, late evening and nighttime hours. The aerosol was found to be highly acidic with calculated aerosol pH varying from 0.5 to 2.8 throughout the study period. Biomass burning aerosol presented the highest values of pH in the submicron fraction and the lowest values in total water mass concentration. The low pH values observed in the submicron mode and independently of air masses origin could increase nutrient availability and especially P solubility, which is the nutrient limiting sea water productivity of the eastern Mediterranean.

Effects of rapeseed meal fiber content on phosphorus and calcium digestibility in growing pigs fed diets without or with microbial phytase.

PubMed

Bournazel, M; Lessire, M; Duclos, M J; Magnin, M; Même, N; Peyronnet, C; Recoules, E; Quinsac, A; Labussière, E; Narcy, A

2018-01-01

The optimization of dietary phosphorus (P) and calcium (Ca) supply requires a better understanding of the effect of dietary fiber content of co-products on the digestive utilization of minerals. This study was designed to evaluate the effects of dietary fiber content from 00-rapeseed meal (RSM) on P and Ca digestibility throughout the gastrointestinal tract in growing pigs fed diets without or with microbial phytase. In total, 48 castrated male pigs (initial BW=36.1±0.4 kg) were housed in metabolic crates for 29 days. After an 8-day adaptation period, pigs were allocated to one of the eight treatments. The impact of dietary fiber was modulated by adding whole RSM (wRSM), dehulled RSM (dRSM) or dRSM supplemented with 4.5% or 9.0% rapeseed hulls (dRSMh1 and dRSMh2). Diets contained 0 or 500 phytase unit of microbial phytase per kg. From day 14 to day 23, feces and urine were collected separately to determine apparent total tract digestibility (ATTD) and apparent retention (AR) of P and Ca. At the end of the experiment, femurs and digestive contents were sampled. No effect of variables of interest was observed on growth performance. Microbial phytase increased ATTD and AR of P (P<0.001) but the P equivalency with the wRSM diet was lower than expected. Moreover, stomach inorganic P (iP) solubility was improved by microbial phytase (P<0.001). The ATTD of Ca was not affected by microbial phytase which increased AR of Ca and femur characteristics (P<0.05). Ileal recovery of P was not affected by microbial phytase but cecal recovery was considerably reduced by microbial phytase (P<0.001). The decrease in digesta pH between the distal ileum and cecum (7.6 v. 5.9) enhanced the solubility of iP and may have improved its absorption, as supported by the negative relationship between soluble iP and pH (R 2=0.40, P<0.001 without microbial phytase and R 2=0.24, P=0.026 with microbial phytase). The inclusion of hulls improved the solubility of iP (P<0.05). In conclusion, dehulling does not largely increase nutrient digestibility although dRSM seems to improve the efficacy of microbial phytase in releasing phosphate in the stomach. Moreover, dietary fiber may affect solubilization process in the cecum which potentiates the effect of microbial phytase on P digestibility.

Coupled phase and aqueous species equilibrium of the H 2O-CO 2-NaCl-CaCO 3 system from 0 to 250 °C, 1 to 1000 bar with NaCl concentrations up to saturation of halite

NASA Astrophysics Data System (ADS)

Duan, Zhenhao; Li, Dedong

2008-10-01

A model is developed for the calculation of coupled phase and aqueous species equilibrium in the H 2O-CO 2-NaCl-CaCO 3 system from 0 to 250 °C, 1 to 1000 bar with NaCl concentrations up to saturation of halite. The vapor-liquid-solid (calcite, halite) equilibrium together with the chemical equilibrium of H +, Na +, Ca 2+, CaHCO3+, Ca(OH) +, OH -, Cl -, HCO3-, CO32-, CO 2(aq) and CaCO 3(aq) in the aqueous liquid phase as a function of temperature, pressure, NaCl concentrations, CO 2(aq) concentrations can be calculated, with accuracy close to those of experiments in the stated T- P- m range, hence calcite solubility, CO 2 gas solubility, alkalinity and pH values can be accurately calculated. The merit and advantage of this model is its predictability, the model was generally not constructed by fitting experimental data. One of the focuses of this study is to predict calcite solubility, with accuracy consistent with the works in previous experimental studies. The resulted model reproduces the following: (1) as temperature increases, the calcite solubility decreases. For example, when temperature increases from 273 to 373 K, calcite solubility decreases by about 50%; (2) with the increase of pressure, calcite solubility increases. For example, at 373 K changing pressure from 10 to 500 bar may increase calcite solubility by as much as 30%; (3) dissolved CO 2 can increase calcite solubility substantially; (4) increasing concentration of NaCl up to 2 m will increase calcite solubility, but further increasing NaCl solubility beyond 2 m will decrease its solubility. The functionality of pH value, alkalinity, CO 2 gas solubility, and the concentrations of many aqueous species with temperature, pressure and NaCl (aq) concentrations can be found from the application of this model. Online calculation is made available on www.geochem-model.org/models/h2o_co2_nacl_caco3/calc.php.

Spectroscopic characterization of the coordination chemistry and hydrolysis of gallium(III) in the presence of aquatic organic matter

NASA Astrophysics Data System (ADS)

Hagvall, Kristoffer; Persson, Per; Karlsson, Torbjörn

2014-12-01

Interactions between metals and natural organic matter (NOM) are of great environmental importance and one of the key factors influencing hydrolysis, solubility, and speciation of the metals. However, studying geochemically relevant metals like Al, Fe, and Cu is sometimes associated with analytical problems; for example Fe and Cu are both redox active. Gallium (Ga) is a non-redox active metal that usually occurs at very low concentrations in environmental samples and therefore a wide concentration range of metal(III)-NOM species can be explored by adding Ga(III) to such samples. This makes Ga(III) a good probe and analogue for other metal ions, in particular Al. In addition, due to the increased usage of Ga in society, a better understanding of how Ga interacts with NOM is of importance but such studies are scarce. In this work, Ga(III) interactions with two different organic materials (Suwannee River natural organic matter and Suwannee River fulvic acid) were studied using infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopy in a large experimental range (101-84,076 μg Ga g-1 dry weight; pH 3-8). Our IR spectroscopic results showed that Ga(III) is bonded mainly to carboxylic functional groups and suggested that only a fraction of the total number of carboxylic sites in the samples was actively involved in the bonding. Modeling of the EXAFS data revealed that Ga(III) formed mononuclear chelate complexes with NOM that strongly suppressed the hydrolysis and polymerization of Ga(III). At low Ga(III) concentrations (1675-16,649 μg g-1) organic complexes, consisting of 1-3 chelate ring structures, were the dominating species in the entire pH range while at higher concentrations (67,673-84,076 μg g-1, pH 3.0-7.0) we detected mixtures of mononuclear organic Ga(III) complexes, Ga(III) (hydr)oxide, and free Ga(III) (here defined as the hydrated Ga(III) ion and its soluble hydrolysis products). Moreover, the EXAFS results showed significantly higher contribution from second-shell C atoms (9-11) for the Ga(III)-organic complexes at the lowest concentration (101-125 μg g-1, pH 4.9-5.1), indicating formation of cage-like structures similar to Ga(III)-EDTA. Our combined results showed that Ga(III)-NOM interactions can be of importance for the solubility and speciation of Ga in environmental systems. Furthermore, the similarities between Ga(III) and previous Fe(III) results demonstrate that Ga(III) can be utilized as a probe for metal(III)-NOM interactions over an extended experimental range (e.g., pH and metal concentration) and thereby improve our knowledge about these interactions in general.

Alleviation of environmental risks associated with severely contaminated mine tailings using amendments: Modeling of trace element speciation, solubility, and plant accumulation.

PubMed

Pardo, Tania; Bes, Cleménce; Bernal, Maria Pilar; Clemente, Rafael

2016-11-01

Tailings are considered one of the most relevant sources of contamination associated with mining activities. Phytostabilization of mine spoils may need the application of the adequate combination of amendments to facilitate plant establishment and reduce their environmental impact. Two pot experiments were set up to assess the capability of 2 inorganic materials (calcium carbonate and a red mud derivate, ViroBind TM ), alone or in combination with organic amendments, for the stabilization of highly acidic trace element-contaminated mine tailings using Atriplex halimus. The effects of the treatments on tailings and porewater physico-chemical properties and trace-element accumulation by the plants, as well as the processes governing trace elements speciation and solubility in soil solution and their bioavailability were modeled. The application of the amendments increased tailings pH and decreased (>99%) trace elements solubility in porewater, but also changed the speciation of soluble Cd, Cu, and Pb. All the treatments made A. halimus growth in the tailings possible; organic amendments increased plant biomass and nutritional status, and reduced trace-element accumulation in the plants. Tailings amendments modified trace-element speciation in porewater (favoring the formation of chlorides and/or organo-metallic forms) and their solubility and plant uptake, which were found to be mainly governed by tailing/porewater pH, electrical conductivity, and organic carbon content, as well as soluble/available trace-element concentrations. Environ Toxicol Chem 2016;35:2874-2884. © 2016 SETAC. © 2016 SETAC.

Enhanced water-solubility and antibacterial activity of novel chitosan derivatives modified with quaternary phosphonium salt.

PubMed

Zhu, Dan; Cheng, Honghao; Li, Jianna; Zhang, Wenwen; Shen, Yuanyuan; Chen, Shaojun; Ge, Zaochuan; Chen, Shiguo

2016-04-01

Chitosan (CS) has been widely recognized as an important biomaterial due to its good antimicrobial activity, biocompatibility and biodegradability. However, CS is insoluble in water in neutral and alkaline aqueous solution due to the linear aggregation of chain molecules and the formation of crystallinity. This is one of the key factors that limit its practical applications. Therefore, improving the solubility of CS in neutral and alkaline aqueous solution is a primary research direction for biomedical applications. In this paper, a reactive antibacterial compound (4-(2,5-Dioxo-pyrrolidin-1-yloxycarbonyl)-benzyl)-triphenyl-phosphonium bromide (NHS-QPS) was synthesized for chemical modification of CS, and a series of novel polymeric antimicrobial agents, N-quaternary phosphonium chitosan derivatives (N-QPCSxy, x=1-2,y=1-4) were obtained. The water solubilities and antibacterial activities of N-QPCSxy against Escherichia coli and Staphylococcus aureus were evaluated compare to CS. The water solubility of N-QPCSxy was all better than that of CS at neutral pH aqueous solution, particularly, N-QPCS14 can be soluble in water over the pH range of 3 to 12. The antibacterial activities of CS derivatives were improved by introducing quaternary phosphonium salt, and antibacterial activity of N-QPCSxy increases with degree of substitution. Overall, N-QPCS14 represents a novel antibacterial polymer material with good antibacterial activity, waters solubility and low cytotoxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

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

PubMed

Yuvaraja, K; Khanam, Jasmina

2014-08-05

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Solubility of hydrogen in metals and its effect of pore-formation and embrittlement. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Shahani, H. R.

1984-01-01

The effect of alloying elements on hydrogen solubility were determined by evaluating solubility equations and interaction coefficients. The solubility of dry hydrogen at one atmosphere was investigated in liquid aluminum, Al-Ti, Al-Si, Al-Fe, liquid gold, Au-Cu, and Au-Pd. The design of rapid heating and high pressure casting furnaces used in meta foam experiments is discussed as well as the mechanism of precipitation of pores in melts, and the effect of hydrogen on the shrinkage porosity of Al-Cu and Al-Si alloys. Hydrogen embrittlement in iron base alloys is also examined.

Divalent metals and pH alter raltegravir disposition in vitro.

PubMed

Moss, Darren M; Siccardi, Marco; Murphy, Matthew; Piperakis, Michael M; Khoo, Saye H; Back, David J; Owen, Andrew

2012-06-01

Raltegravir shows marked pharmacokinetic variability in patients, with gastrointestinal pH and divalent-metal binding being potential factors. We investigated raltegravir solubility, lipophilicity, pK(a), and permeativity in vitro to elucidate known interactions with omeprazole, antacids, and food, all of which increase gastric pH. Solubility of raltegravir was determined at pH 1 to 8. Lipophilicity of raltegravir was determined using octanol-water partition. Raltegravir pK(a) was determined using UV spectroscopy. The effects of pH, metal salts, and omeprazole on the cellular permeativity of raltegravir were determined using Caco-2 monolayers. Cellular accumulation studies were used to determine the effect of interplay between pH and ABCB1 transport on raltegravir accumulation. Samples were analyzed using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) or scintillation counting. Raltegravir at 10 mM was partly insoluble at pH 6.6 and below. Raltegravir lipophilicity was pH dependent and was reduced as pH was increased from 5 to 9. The pK(a) of raltegravir was 6.7. Raltegravir cellular permeativity was heavily influenced by changes in extracellular pH, where apical-to-basolateral permeativity was reduced 9-fold (P < 0.05) when apical pH was increased from 5 to 8.5. Raltegravir cellular permeativity was also reduced in the presence of magnesium and calcium. Omeprazole did not alter raltegravir cellular permeativity. Cellular accumulation of raltegravir was increased independently by inhibiting ABCB1 and by lowering extracellular pH from pH 8 to 5. Gastrointestinal pH and polyvalent metals can potentially alter the pharmacokinetic properties of raltegravir, and these data provide an explanation for the variability in raltegravir exposure in patients. The evaluation of how divalent-metal-containing products, such as multivitamins, that do not affect gastric pH alter raltegravir pharmacokinetics in patients is now justified.

Divalent Metals and pH Alter Raltegravir Disposition In Vitro

PubMed Central

Moss, Darren M.; Siccardi, Marco; Murphy, Matthew; Piperakis, Michael M.; Khoo, Saye H.; Back, David J.

2012-01-01

Raltegravir shows marked pharmacokinetic variability in patients, with gastrointestinal pH and divalent-metal binding being potential factors. We investigated raltegravir solubility, lipophilicity, pKa, and permeativity in vitro to elucidate known interactions with omeprazole, antacids, and food, all of which increase gastric pH. Solubility of raltegravir was determined at pH 1 to 8. Lipophilicity of raltegravir was determined using octanol-water partition. Raltegravir pKa was determined using UV spectroscopy. The effects of pH, metal salts, and omeprazole on the cellular permeativity of raltegravir were determined using Caco-2 monolayers. Cellular accumulation studies were used to determine the effect of interplay between pH and ABCB1 transport on raltegravir accumulation. Samples were analyzed using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) or scintillation counting. Raltegravir at 10 mM was partly insoluble at pH 6.6 and below. Raltegravir lipophilicity was pH dependent and was reduced as pH was increased from 5 to 9. The pKa of raltegravir was 6.7. Raltegravir cellular permeativity was heavily influenced by changes in extracellular pH, where apical-to-basolateral permeativity was reduced 9-fold (P < 0.05) when apical pH was increased from 5 to 8.5. Raltegravir cellular permeativity was also reduced in the presence of magnesium and calcium. Omeprazole did not alter raltegravir cellular permeativity. Cellular accumulation of raltegravir was increased independently by inhibiting ABCB1 and by lowering extracellular pH from pH 8 to 5. Gastrointestinal pH and polyvalent metals can potentially alter the pharmacokinetic properties of raltegravir, and these data provide an explanation for the variability in raltegravir exposure in patients. The evaluation of how divalent-metal-containing products, such as multivitamins, that do not affect gastric pH alter raltegravir pharmacokinetics in patients is now justified. PMID:22450971

Serum amyloid A forms stable oligomers that disrupt vesicles at lysosomal pH and contribute to the pathogenesis of reactive amyloidosis

PubMed Central

Gantz, Donald L.; Haupt, Christian; Gursky, Olga

2017-01-01

Serum amyloid A (SAA) is an acute-phase plasma protein that functions in innate immunity and lipid homeostasis. SAA is a protein precursor of reactive AA amyloidosis, the major complication of chronic inflammation and one of the most common human systemic amyloid diseases worldwide. Most circulating SAA is protected from proteolysis and misfolding by binding to plasma high-density lipoproteins. However, unbound soluble SAA is intrinsically disordered and is either rapidly degraded or forms amyloid in a lysosome-initiated process. Although acidic pH promotes amyloid fibril formation by this and many other proteins, the molecular underpinnings are unclear. We used an array of spectroscopic, biochemical, and structural methods to uncover that at pH 3.5–4.5, murine SAA1 forms stable soluble oligomers that are maximally folded at pH 4.3 with ∼35% α-helix and are unusually resistant to proteolysis. In solution, these oligomers neither readily convert into mature fibrils nor bind lipid surfaces via their amphipathic α-helices in a manner typical of apolipoproteins. Rather, these oligomers undergo an α-helix to β-sheet conversion catalyzed by lipid vesicles and disrupt these vesicles, suggesting a membranolytic potential. Our results provide an explanation for the lysosomal origin of AA amyloidosis. They suggest that high structural stability and resistance to proteolysis of SAA oligomers at pH 3.5–4.5 help them escape lysosomal degradation, promote SAA accumulation in lysosomes, and ultimately damage cellular membranes and liberate intracellular amyloid. We posit that these soluble prefibrillar oligomers provide a missing link in our understanding of the development of AA amyloidosis. PMID:28743750

Monitoring the kinetics of the pH-driven transition of the anthrax toxin prepore to the pore by biolayer interferometry and surface plasmon resonance.

PubMed

Naik, Subhashchandra; Brock, Susan; Akkaladevi, Narahari; Tally, Jon; McGinn-Straub, Wesley; Zhang, Na; Gao, Phillip; Gogol, E P; Pentelute, B L; Collier, R John; Fisher, Mark T

2013-09-17

Domain 2 of the anthrax protective antigen (PA) prepore heptamer unfolds and refolds during endosome acidification to generate an extended 100 Å β barrel pore that inserts into the endosomal membrane. The PA pore facilitates the pH-dependent unfolding and translocation of bound toxin enzymic components, lethal factor (LF) and/or edema factor, from the endosome to the cytoplasm. We constructed immobilized complexes of the prepore with the PA-binding domain of LF (LFN) to monitor the real-time prepore to pore kinetic transition using surface plasmon resonance and biolayer interferometry (BLI). The kinetics of this transition increased as the solution pH was decreased from 7.5 to 5.0, mirroring acidification of the endosome. Once it had undergone the transition, the LFN-PA pore complex was removed from the BLI biosensor tip and deposited onto electron microscopy grids, where PA pore formation was confirmed by negative stain electron microscopy. When the soluble receptor domain (ANTRX2/CMG2) binds the immobilized PA prepore, the transition to the pore state was observed only after the pH was lowered to early (pH 5.5) or late (pH 5.0) endosomal pH conditions. Once the pore formed, the soluble receptor readily dissociated from the PA pore. Separate binding experiments with immobilized PA pores and the soluble receptor indicate that the receptor has a weakened propensity to bind to the transitioned pore. This immobilized anthrax toxin platform can be used to identify or validate potential antimicrobial lead compounds capable of regulating and/or inhibiting anthrax toxin complex formation or pore transitions.

Enteric polymers as acidifiers for the pH-independent sustained delivery of a weakly basic drug salt from coated pellets.

PubMed

Körber, Martin; Ciper, Mesut; Hoffart, Valerie; Pearnchob, Nantharat; Walther, Mathias; Macrae, Ross J; Bodmeier, Roland

2011-08-01

Weakly basic drugs and their salts exhibit a decrease in aqueous solubility at higher pH, which can result in pH-dependent or even incomplete release of these drugs from extended release formulations. The objective of this study was to evaluate strategies to set-off the very strong pH-dependent solubility (solubility: 80 mg/ml at pH 2 and 0.02 mg/ml at pH 7.5, factor 4000) of a mesylate salt of weakly basic model drug (pK(a) 6.5), in order to obtain pH-independent extended drug release. Three approaches for pH-independent release were investigated: (1) organic acid addition in the core, (2) enteric polymer addition to the extended release coating and (3) an enteric polymer subcoating below the extended release coating. The layering of aspartic acid onto drug cores as well as the coating of drug cores with an ethylcellulose/Eudragit L (enteric polymer) blend were not effective to avoid the formation of the free base at pH 7.5 and thus failed to significantly improve the completeness of the release compared to standard ethylcellulose/hydroxypropyl cellulose (EC/HPC)-coated drug pellets. Interestingly, the incorporation of an enteric polymer layer underneath the EC/HPC coating decreased the free base formation at pH 7.5 and thus resulted in a more complete release of up to 90% of the drug loading over 18 h. The release enhancing effect was attributed to an extended acidification through the enteric polymer layer. Flexible release patterns with approximately pH-independent characteristics were successfully achieved. Copyright © 2011 Elsevier B.V. All rights reserved.

Total and soluble oxalate content of some Indian spices.

PubMed

Ghosh Das, Sumana; Savage, G P

2012-06-01

Spices, such as cinnamon, cloves, cardamom, garlic, ginger, cumin, coriander and turmeric are used all over the world as flavouring and colouring ingredients in Indian foods. Previous studies have shown that spices contain variable amounts of total oxalates but there are few reports of soluble oxalate contents. In this study, the total, soluble and insoluble oxalate contents of ten different spices commonly used in Indian cuisine were measured. Total oxalate content ranged from 194 (nutmeg) to 4,014 (green cardamom) mg/100 g DM, while the soluble oxalate contents ranged from 41 (nutmeg) to 3,977 (green cardamom) mg/100 g DM. Overall, the percentage of soluble oxalate content of the spices ranged from 4.7 to 99.1% of the total oxalate content which suggests that some spices present no risk to people liable to kidney stone formation, while other spices can supply significant amounts of soluble oxalates and therefore should be used in moderation.

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 analysis of literature solubility, protonation constants, enthalpies and activity coefficients is reported too. Copyright © 2012 Elsevier B.V. All rights reserved.

Bismuth(III) 5-sulfosalicylate complexes: structure, solubility and activity against Helicobacter pylori.

PubMed

Andrews, Philip C; Deacon, Glen B; Ferrero, Richard L; Junk, Peter C; Karrar, Abdulgader; Kumar, Ish; MacLellan, Jonathan G

2009-08-28

Treatment of 5-sulfosalicylic acid (H(3)Ssal) with BiPh(3) results in the formation of the first dianionic carboxylate-sulfonate bismuth complex, [PhBi(HSsal)H(2)O](infinity) 1a, and its ethanol analogue [PhBi(HSsal)EtOH](infinity) 1b (space group P2(1)/c), while Bi(OAc)(3) gives the mixed monoanionic and dianionic complex, {[Bi(HSsal)(H(2)Ssal)(H(2)O)(3)](2) x 2 H(2)O}(infinity) 2 (space group P1). The three complexes are all polymeric in the solid state as determined by single crystal X-ray diffraction, with extended frameworks constructed from dimeric [Bi(HSsal)](2), 1a and 1b, or from [Bi(HSsal)(H(2)Ssal)](2) units, 2. The heteroleptic bismuth complexes 1a and 2 display remarkable aqueous solubility, 10 and 2.5 mg ml(-1) respectively, resulting in a clear solution of pH 1.5. In contrast, 1b is essentially insoluble in aqueous environments. All three complexes show significant activity against the bacterium Helicobacter pylori of <6.25 microg ml(-1).

Solubility of guaifenesin in the presence of common pharmaceutical additives.

PubMed

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

2003-01-01

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

Rainwater analysis by synchrotron radiation-total reflection X-ray fluorescence

NASA Astrophysics Data System (ADS)

López, María L.; Ceppi, Sergio A.; Asar, María L.; Bürgesser, Rodrigo E.; Ávila, Eldo E.

2015-11-01

Total reflection X-ray fluorescence analysis excited with synchrotron radiation was used to quantify the elemental concentration of rainwater in Córdoba, Argentina. Standard solutions with gallium as internal standard were prepared for the calibration curves. Rainwater samples of 5 μl were added to an acrylic reflector, allowed to dry, and analyzed for 200 s measuring time. The elemental concentrations of As, Ca, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, S, Sr, V, and Zn were determined. The electrical conductivity, pH, and elemental concentrations were compared to data previously reported for the soluble fraction of rainwater at different sites. A factor analysis was performed in order to determine the sources that contributed to the elemental concentration in rainwater. Anthropogenic sources were identified as traffic pollution, vehicular emissions, and metallurgical factories. The quality of rainwater was analyzed by comparing the concentrations of all the elements in rainwater samples with the WHO guideline values for drinking water. The results show the need to control the atmospheric emissions in order to preserve the quality of rainwater. SR-TXRF analysis of chemical composition of rainwater in Córdoba represents the very first contribution in the region to the knowledge of the concentration of trace metals in the soluble fraction of rainwater. These data are scarce, especially in the Southern Hemisphere.

Effect of methods of preparation on distribution of heavy metals in different size fractions of municipal solid waste composts.

PubMed

Saha, J K; Panwar, N R; Coumar, M Vassanda

2013-11-01

The present study compares the distribution and nature of heavy metals in composts from 12 cities of India, prepared from different types of processed urban solid wastes, namely mixed wastes (MWC), partially segregated wastes (PSWC), and segregated bio-wastes (BWC). Compost samples were physically fractionated by wet sieving, followed by extraction of heavy metals by dilute HCl and NaOH. Bigger particles (>0.5 mm) constituted the major fraction in all three types of composts and had a relatively lower concentration of organic matter and heavy metals, the effect being more pronounced in MWC and PSWC in which a significant portion of the heavy metals was distributed in finer size fractions. Cd, Ni, Pb, and Zn were extracted to a greater extent by acid than by alkali, the difference being greater in MWC, which contained a higher amount of mineral matter. In contrast, Cu and Cr were extracted to a greater extent by dilute alkali, particularly from BWC containing a higher amount of organic matter. Water-soluble heavy metals were generally related to the water-soluble C or total C content as well as to pH, rather than to their total contents. This study concludes that wet sieving with dilute acid can effectively reduce heavy metal load in MWC and PSWC.

Determining the Solubility Product of Fe(OH)[subscript 3]: An Equilibrium Study with Environmental Significance

ERIC Educational Resources Information Center

Meighan, Michelle; MacNeil, Joseph; Falconer, Renee

2008-01-01

The relationship between pH and the aqueous solubility of heavy metals is explored by considering the environmental impact of acidic mine drainage. Acid mine drainage is an important environmental concern in many areas of the United States. Associated with coal mining in the East and hard rock mining in the West, the acidity originates primarily…

Adsorption of peroxidase on Celite 545 directly from ammonium sulfate fractionated white radish (Raphanus sativus) proteins.

PubMed

Satar, Rukhsana; Husain, Qayyum

2009-03-01

This paper demonstrates the direct immobilization of peroxidase from ammonium sulfate fractionated white radish proteins on an inorganic support, Celite 545. The adsorbed peroxidase was crosslinked by using glutaraldehyde. The activity yield for white radish peroxidase was adsorbed on Celite 545 was 70% and this activity was decreased and remained 60% of the initial activity after crosslinking by glutaraldehyde. The pH and temperature-optima for both soluble and immobilized peroxidase was at pH 5.5 and 40 degrees C. Immobilized peroxidase retained higher stability against heat and water-miscible organic solvents. In the presence of 5.0 mM mercuric chloride, immobilized white radish peroxidase retained 41% of its initial activity while the free enzyme lost 93% activity. Soluble enzyme lost 61% of its initial activity while immobilized peroxidase retained 86% of the original activity when exposed to 0.02 mM sodium azide for 1 h. The K(m) values were 0.056 and 0.07 mM for free and immobilized enzyme, respectively. Immobilized white radish peroxidase exhibited lower V(max) as compared to the soluble enzyme. Immobilized peroxidase preparation showed better storage stability as compared to its soluble counterpart.

[Isolation and purification of recombinant soluble and non-fusion angiogenesis inhibitor Kringle 5 using chromatography].

PubMed

Ma, Lina; Wu, Dan; Bian, Liujiao

2012-08-01

The Kringle 5 domain of plasminogen is one of the most potent angiogenesis inhibitors known to date, which can inhibit cell proliferation and migration efficiently. In the study, on the foundation of successful clone and expression of recombinant soluble and non-fusion angiogenesis inhibitor Kringle 5, a two-step chromatographic method, including the use of SP Sepharose Fast Flow cation exchanger and Sephacryl S-100 HR size exclusion chromatography in sequence, was established to separate and purify angiogenesis inhibitor Kringle 5. On the SP Sepharose Fast Flow column, the buffer A consisted of 50.0 mmol/L acetic acid-sodium acetate (pH 5.2), and the buffer B consisted of buffer A with the addition of 0.5 mol/L sodium chloride (pH 5.2); on Sephacryl S-100 HR column, the elution buffer was 5.0 mmol/L phosphate solution (pH 7.0). Through the two-step chromatographic purification process, the purity of the obtained Kringle 5 was more than 98%. In addition, it was found that the obtained Kringle 5 could inhibit the blood vessel growth of chick embryo chorioallantoic membrane effectively. Finally it is concluded that this method can effectively separate active recombinant soluble and non-fusion angiogenesis inhibitor Kringle 5.

A supersaturating delivery system of silibinin exhibiting high payload achieved by amorphous nano-complexation with chitosan.

PubMed

Nguyen, Minh-Hiep; Yu, Hong; Dong, Bingxue; Hadinoto, Kunn

2016-06-30

The therapeutic potentials of silibinin - a phytochemical isolated from milk thistle plants - have not been fully realized due to its poor oral bioavailability caused by the low aqueous solubility. Existing solubility enhancement strategies of silibinin by nanonization were limited by their low payload. Herein we developed a supersaturating delivery system of silibinin exhibiting a high payload (≈76%) in the form of amorphous silibinin-chitosan nanoparticle complex (or silibinin nanoplex in short) prepared by self-assembly drug-polysaccharide complexation. The effects of (1) pH and (2) charge ratio of chitosan to silibinin on the nanoplex's physical characteristics (i.e. size, zeta potential, and payload) and preparation efficiency (i.e. silibinin utilization, overall yield) were investigated. The formation of nanoplex (≈240nm) was feasible only in a narrow pH range (5.1-5.8) and favored charge ratio below unity. At the optimal condition (pH 5.8 and charge ratio of 0.30), the nanoplex preparation exhibited 87% silibinin utilization rate and 63% yield signifying its high efficiency. The amorphous state and colloidal stabilities of the nanoplex during storage, and prolonged supersaturation generation (3h) at more than 10× of the saturation solubility were successfully demonstrated. Copyright © 2016 Elsevier B.V. All rights reserved.

The influence of non-ionisable excipients on precipitation parameters measured using the CheqSol method.

PubMed

Etherson, Kelly; Halbert, Gavin; Elliott, Moira

2016-09-01

The aim of this study was to determine the influence of non-ionisable excipients hydroxypropyl-β-cyclodextrin (HPβCD) and poloxamers 407 and 188 on the supersaturation and precipitation kinetics of ibuprofen, gliclazide, propranolol and atenolol induced through solution pH shifts using the CheqSol method. The drug's kinetic and intrinsic aqueous solubilities were measured in the presence of increasing excipient concentrations using the CheqSol method. Experimental data rate of change of pH with time was also examined to determine excipient-induced parachute effects and influence on precipitation rates. The measured kinetic and intrinsic solubilities provide a determination of the influence of each excipient on supersaturation index, and the area under the CheqSol curve can measure the parachute capability of excipients. The excipients influence on precipitation kinetics can be measured with novel parameters; for example, the precipitation pH or percentage ionised drug at the precipitation point, which provide further information on the excipient-induced changes in precipitation performance. This method can therefore be employed to measure the influence of non-ionisable excipients on the kinetic solubility behaviour of supersaturated solutions of ionisable drugs and to provide data, which discriminates between excipient systems during precipitation. © 2016 Royal Pharmaceutical Society.

Poly(aspartic acid) with adjustable pH-dependent solubility.

PubMed

Németh, Csaba; Gyarmati, Benjámin; Abdullin, Timur; László, Krisztina; Szilágyi, András

2017-02-01

Poly(aspartic acid) (PASP) derivatives with adjustable pH-dependent solubility were synthesized and characterized to establish the relationship between their structure and solubility in order to predict their applicability as a basic material for enteric coatings. Polysuccinimide, the precursor of PASP, was modified with short chain alkylamines, and the residual succinimide rings were subsequently opened to prepare the corresponding PASP derivatives. Study of the effect of the type and concentration of the side groups on the pH-dependent solubility of PASP showed that solubility can be adjusted by proper selection of the chemical structure. The Henderson-Hasselbalch (HH) and the extended HH equations were used to describe the pH-dependent solubility of the polymers quantitatively. The estimate provided by the HH equation is poor, but an accurate description of the pH-dependent solubility can be found with the extended HH equation. The dissolution rate of a polymer film prepared from a selected PASP derivative was determined by fluorescence marking. The film dissolved rapidly when the pH was increased above its pK a . Cellular viability tests show that PASP derivatives are non-toxic to a human cell line. These polymers are thus of great interest as starting materials for enteric coatings. Poly(amino acid) type biocompatible polymers were synthesized for future use as pharmaceutical film coatings. To this end, we tailored the pH-dependent solubility of poly(aspartic acid) (PASP). It was found that both the solubility and the pK a values of the modified PASP depended strongly on composition. Fluorescent marking was used to characterize the dissolution of a chosen PASP derivative. In acidic media only a negligible amount of the polymer dissolved, but dissolution was very fast and complete at the pH values that prevail in the small intestine. As a consequence, enteric coatings based on such PASP derivatives may be used for drug delivery in the gastrointestinal tract. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 2. Light Lanthanides (Ce-Eu)

NASA Astrophysics Data System (ADS)

Mioduski, Tomasz; Gumiński, Cezary; Zeng, Dewen

2015-03-01

This is the second part of the volume devoted to the evaluation of experimental solubility data for rare earth metal (REM) fluorides in water as well as in aqueous ternary and multicomponent systems. Fluorides of Ce, Pr, Nd, Pm, Sm, and Eu (so-called light lanthanides), as the main solutes, are covered in the present part, which has thorough coverage of the experimental literature through the end of 2012. The experimentally unknown solubility value for PmF3 in water was predicted by an interpolation of the solubility values for NdF3 and SmF3 at 298 K. General features of the systems, such as the nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, pH, mixed solvent medium on the solubility, quality of the solubility results, and solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

Conversion of spent mushroom substrate to biofertilizer using a stress-tolerant phosphate-solubilizing Pichia farinose FL7.

PubMed

Zhu, Hong-Ji; Sun, Li-Fan; Zhang, Yan-Fei; Zhang, Xiao-Li; Qiao, Jian-Jun

2012-05-01

To develop high-efficient biofertilizer, an environmental stress-tolerant phosphate-solubilizing microorganism (PSM) was isolated from agricultural wastes compost, and then applied to spent mushroom substrate (SMS). The isolate FL7 was identified as Pichia farinose with resistance against multiple environmental stresses, including 5-45°C temperature, 3-10 pH range, 0-23% (w/v) NaCl and 0-6M ammonium ion. Under the optimized cultivation condition, 852.8 mg/l total organic acids can be produced and pH can be reduced to 3.8 after 60 h, meanwhile, the soluble phosphate content reached 816.16 mg/l. The P. farinose was used to convert SMS to a phosphate biofertilizer through a semi-solid fermentation (SSF) process. After fermentation of 10 days, cell density can be increased to 5.6 × 10(8)CFU/g in biomass and pH in this medium can be decreased to 4.0. SMS biofertilizer produced by P. farinose significantly improved the growth of soybean in pot experiments, demonstrating a tremendous potential in agricultural application. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of pretreatments on anthocyanin composition, phenolics contents and antioxidant capacities during fermentation of hawthorn (Crataegus pinnatifida) drink.

PubMed

Liu, Suwen; Chang, Xuedong; Liu, Xiufeng; Shen, Zhanwei

2016-12-01

The effect of microwave and heat pretreatment on the content and composition of anthocyanins, phenolics, and the antioxidant capacity of hawthorn drink were studied. Nine anthocyanins were isolated by chromatographic separation from the Zirou hawthorn source and their structure identified using HPLC-DAD-ESI/MS analysis. Heat and microwave pretreatments had a significant impact on the relative contents of hawthorn anthocyanins, such as cyanidin-3-galactoside (82.9% and 76.9%, respectively) and cyanidin-3-glucoside (9.2% and 11.5%, respectively). Pretreatment had no significant effect on pH, total soluble solid or total acid. More anthocyanins remained after heat treatment than after microwaving (0.745mg/100mL), and were 52.4% higher than the control group after storage for 7days. The colour density of the heat treated group was higher than the control group (24.5%) after 12days of fermentation. The main antioxidant capacities of the hawthorn drinks came from total polyphenolics rather than total anthocyanins or total flavonoids. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gluconic acid production and phosphate solubilization by the plant growth-promoting bacterium Azospirillum spp.

NASA Astrophysics Data System (ADS)

Rodriguez, Hilda; Gonzalez, Tania; Goire, Isabel; Bashan, Yoav

2004-11-01

In vitro gluconic acid formation and phosphate solubilization from sparingly soluble phosphorus sources by two strains of the plant growth-promoting bacteria A. brasilense (Cd and 8-I) and one strain of A. lipoferum JA4 were studied. Strains of A. brasilense were capable of producing gluconic acid when grown in sparingly soluble calcium phosphate medium when their usual fructose carbon source is amended with glucose. At the same time, there is a reduction in pH of the medium and release of soluble phosphate. To a greater extent, gluconic acid production and pH reduction were observed for A. lipoferum JA4. For the three strains, clearing halos were detected on solid medium plates with calcium phosphate. This is the first report of in vitro gluconic acid production and direct phosphate solubilization by A. brasilense and the first report of P solubilization by A. lipoferum. This adds to the very broad spectrum of plant growth-promoting abilities of this genus.

Serum albumin forms a lactoferrin-like soluble iron-binding complex in presence of hydrogen carbonate ions.

PubMed

Ueno, Hiroshi M; Urazono, Hiroshi; Kobayashi, Toshiya

2014-02-15

The iron-lactoferrin complex is a common food ingredient because of its iron-solubilizing capability in the presence of hydrogen carbonate ions. However, it is unclear whether the formation of a stable iron-binding complex is limited to lactoferrin. In this study, we investigated the effects of bovine serum albumin (BSA) on iron solubility and iron-catalyzed lipid oxidation in the presence of hydrogen carbonate ions. BSA could solubilize >100-fold molar equivalents of iron at neutral pH, exceeding the specific metal-binding property of BSA. This iron-solubilizing capability of BSA was impaired by thermally denaturing BSA at ≥ 70 °C for 10 min at pH 8.5. The resulting iron-BSA complex inhibited iron-catalyzed oxidation of soybean oil in a water-in-oil emulsion measured using the Rancimat test. Our study is the first to show that BSA, like lactoferrin, forms a soluble iron-binding complex in the presence of hydrogen carbonate ions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microencapsulation by freeze-drying of potassium norbixinate and curcumin with maltodextrin: stability, solubility, and food application.

PubMed

Sousdaleff, Mirian; Baesso, Mauro Luciano; Medina Neto, Antonio; Nogueira, Ana Cláudia; Marcolino, Vanessa Aparecida; Matioli, Graciette

2013-01-30

Stability of potassium norbixinate and curcumin by microencapsulation with maltodextrin DE20 and freeze-drying was evaluated as a function of exposition to light, air, different pH, water solubility, and in food applications. The best results were obtained with microencapsulated potassium norbixinate 1:20, which, when vacuum-packed and in the presence of natural light, showed color retention of 78%, while microencapsulated curcumin 1:20 showed color retention of 71%. Differential scanning calorimetry and thermogravimetry provided an indication of interaction between colorants and maltodextrin. Photoacoustic spectroscopy (PAS) showed that free and microencapsulated colorants exhibited high rates of absorption throughout the measured spectral region. This work evidenced that the freeze-drying process is favorable for microencapsulation of curcumin by maltodextrin, providing improved solubility to the microencapsulated colorant. Both microencapsulated colorants showed relevant results for use in a wide range of pH and food applications. The PAS technique was useful for the evaluation of the stability of free and microencapsulated colorants.

Influence of an americium solid phase on americium concentrations in solutions

NASA Astrophysics Data System (ADS)

Rai, Dhanpat; Strickert, R. G.; Moore, D. A.; Serne, R. J.

1981-11-01

Americium-241 concentrations in solutions contacting contaminated sediments for up to 2 yr were measured as a function of pH. Steady-state concentrations were reached within a few days. The solubility-limited Am concentration was found to decrease approximately 10-fold with one unit increase in pH. The log equilibrium constant for the solubility of Am (soil) solid [Am (soil) + H + ⇌ Am (aq complex)+] was found to be -4.12. The predictions based upon thermodynamic data suggest that Am (aq complex)+ is likely to be Am(OH) 2+. Although the chemical formula of Am (soil) was not determined, it does not appear to be Am(OH) 3(a). Published data on sorption coefficients of Am by different rocks, soils, and minerals were critically evaluated. Final Am solution concentrations calculated from the sorption coefficients of a variety of earth materials with several solutions agreed well with the concentrations predicted from the solubility of Am (soil) solid, indicating that the sorption coefficient data are controlled by Am precipitation.

Interactions between a poorly soluble cationic drug and sodium dodecyl sulfate in dissolution medium and their impact on in vitro dissolution behavior.

PubMed

Huang, Zongyun; Parikh, Shuchi; Fish, William P

2018-01-15

In the pharmaceutical industry, in vitro dissolution testing ofsolid oral dosage forms is a very important tool for drug development and quality control. However, ion-pairing interaction between the ionic drugand surfactants in dissolution medium often occurs, resulting in inconsistent and incomplete drug release. The aim of this study is toevaluate the effects ofsodium dodecyl sulfate (SDS) mediated medium onthe dissolution behaviors of a poorly soluble cationic drug (Drug B). The study was carried out by measuring solubility of Drug B substance and dissolution rate of Drug B product in media containing SDS.Desolubilization of Drug B substance was observed at pH 4.5 in the presence of SDS at concentrations below critical micelle concentration (CMC) which is attributed to the formation of an insoluble di-dodecyl sulfate salt between SDS and Drug B. This ion-pairing effect is less significant with increasing medium pH where Drug B is less ionized and CMC of SDS is lower. In medium at pH 4.5, dissolution of Drug B product was found incomplete with SDS concentration below CMC due to the desolubilization of Drug B substance. In media with SDS level above CMC, the dissolution rate is rather slower with higher inter-vessel variations compared to that obtained in pH 4.5 medium without SDS. The dissolution results demonstrate that the presence of SDS in medium generates unexpected irregular dissolution profiles for Drug B which are attributed to incompatible dissolution medium for this particular drug. Therefore, non-ionic surfactant was selected for Drug B product dissolution method and ion-pairing effect in SDS mediated medium should be evaluated when developing a dissolution method for any poorly soluble cationic drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Solubility of root-canal sealers in water and artificial saliva.

PubMed

Schäfer, E; Zandbiglari, T

2003-10-01

To compare the weight loss of eight different root-canal sealers in water and in artificial saliva with different pH values. For standardized samples (n = 12 per group), ring moulds were filled with epoxy resin (AH 26, AH Plus)-, silicone (RSA RoekoSeal)-, calcium hydroxide (Apexit, Sealapex)-, zinc oxide-eugenol (Aptal-Harz)-, glass-ionomer (Ketac Endo)- and polyketone (Diaket)-based sealers. These samples were immersed in double-distilled water or artificial saliva with different pH values (7.0, 5.7 and 4.5) for 30 s, 1 min, 2 min, 5 min, 10 min, 20 min, 1 h, 2 h, 10 h, 24 h, 48 h, 72 h, 14 days and 28 days. Mean loss of weight was determined and analysed statistically using a one-way anova and Student-Newman-Keuls test for all pairwise comparisons. Most sealers were of low solubility, although Sealapex, Aptal-Harz and Ketac Endo showed a marked weight loss in all liquids. Even after 28 days of storage in water, AH 26, AH Plus, RSA RoekoSeal, and Diaket showed less than 3% weight loss. At exposure times greater than 14 days, Sealapex showed the significantly greatest weight loss of all sealers tested (P < 0.05). Aptal-Harz and Ketac Endo were significantly more soluble in saliva (pH 4.5) than in water (P < 0.05). Under the conditions of the present study, AH Plus showed the least weight loss of all sealers tested, independent of the solubility medium used. Sealapex, Aptal-Harz and Ketac Endo had a marked weight loss in all liquids.

Poly (amidoamine) dendrimer-mediated hybrid formulation for combination therapy of ramipril and hydrochlorothiazide.

PubMed

Singh, Mayank Kumar; Pooja, Deep; Kulhari, Hitesh; Jain, Sanjay Kumar; Sistla, Ramakrishna; Chauhan, Abhay Singh

2017-01-01

We present a dendrimer-based hybrid formulation strategy to explore the potential of poly (amidoamine) PAMAM dendrimers to be used as drug carriers for combination therapy of an anti-hypertensive drug ramipril (RAPL) and a diuretic hydrochlorothiazide (HCTZ). The drug-dendrimer complexes were prepared by phase-equilibration method. The results showed that the solubility of RAPL and HCTZ was dependent on dendrimer concentration and pH of dendrimer solution. The solubility profile of both RAPL and HCTZ dendrimer complexes illustrated a non-linear relationship with dendrimer concentration. At 0.8% (w/v) dendrimer concentration, solubility of RAPL was increased 4.91 folds with amine-terminated while for HCTZ, solubility enhancement was highest (3.72 folds) with carboxy-terminated. The complexes were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance analysis and high performance liquid chromatography. In-vitro drug dissolution performance of pure drugs, individual drug loaded dendrimer formulations and hybrid formulations was studied in USP dissolution medium (pH7.0) and in simulated gastric fluid (pH1.2). Dendrimer mediated formulations showed faster and complete dissolution compared to pure RAPL or HCTZ. Surprisingly, similar pattern of dissolution profile was established with hybrid formulations as compared to individual drug loaded dendrimers. The dendrimer-based hybrid formulations were found to be stable at dark and refrigerated conditions up to 5weeks. Conclusively, the proposed formulation strategy establishes a novel multitasking platform using dendrimer for simultaneous loading and delivery of multiple drugs for pharmaceutical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhancement of Loperamide Dissolution Rate by Liquisolid Compact Technique.

PubMed

Venkateswarlu, Kambham; Preethi, Jami Komala; Chandrasekhar, Kothapalli Bonnoth

2016-09-01

Purpose: The aim of present study was to improve the dissolution rate of poorly soluble drug Loperamide (LPM) by liquisolid compact technique. Methods: Liquisolid compacts of LPM were prepared using Propylene glycol (PG) as a solvent, Avicel pH 102 as carrier, Aerosil as coating material and Sodium Starch Glycolate (SSG) as superdisintegrant. Interactions between the drug and excipients were examined by Fourier Transform Infrared (FTIR) spectroscopy. The dissolution studies for LPM liquisolid formulation, marketed product and pure drug were carried out in pH 1.2 HCl buffer as dissolution media. Results: Results confirmed the absence of chemical interactions between the drug and excipients. From the solubility studies, it was observed the LPM was highly soluble in PG thereby it was selected as a solvent. The dissolution efficiency of LPM at 15 min was increased from 9.99 % for pure drug and 54.57% for marketed product to 86.81% for the tablets prepared by liquisolid compact technique. Stability studies showed no significant change in percent cumulative drug release, hardness, disintegration time, friability and drug content for 3 months. Conclusion: Formulation F2 showed significant increase in dissolution rate compared to the marketed product at pH 1.2 where LPM is largely absorbed. Around 90% of the drug was released from F2 in 30 min compared to the marketed product and it might be due to the increased wetting and surface area of the particles. Hence, the liquisolid compact technique appears to be a promising approach for improving the dissolution rate of poorly soluble drug.

Solid state manipulation of lornoxicam for cocrystals--physicochemical characterization.

PubMed

Nijhawan, Monika; Santhosh, A; Babu, P R Sathesh; Subrahmanyam, C V S

2014-09-01

Lornoxicam is an analgesic and anti-inflammatory drug of choice and belongs to Class II (low solubility) of BCS (Biopharmaceutical Classification System). Thus bioavailabilities problems are predominant. Through crystal engineering approach, a method was developed for obtaining multi-component cocrystals of lornoxicam using pharmaceutically acceptable compounds as guests. Lornoxicam guest-free form was obtained from solution crystallization. Supramolecular synthon approach indicated that lornoxicam was in orthorhombic form. Further presence of intermolecular hydrogen bonding with layered structures was identified. Solvent drop grinding method permitted the formation of cocrystals of lornoxicam with catechol, resorcinol, benzoic acid, hydroxyquinone and 2,4 dihydroxy benzoic acid, all are capable of forming hydrogen bonding. Lornoxicam cocrystals exhibited the difference in melting points and decomposition characteristics. The analysis of infrared (IR) indicated the shifting of characteristic bands of lornoxicam. The XPRD (X-Ray Powder Diffraction) pattern indicated the crystallinity of cocrystals and significant difference in 2θ value of intense peaks. Differential scanning calorimetry spectra of cocrystals denoted the changes in fusion endotherms, which are in agreements with melting points. The pH solubility profile of lornoxicam showed sigmoidal curve, which substantiated the pKa-dependent solubility. Lornoxicam cocrystals also exhibited a similar pH-solubility profile. Thus pairing of lornoxicam and coformers in the solution at high pH media was assumed. The in vitro dissolution studies of cocrystals were conducted at pH 4.0. The rapid rate of dissolution of cocrystals was observed in initial 10 min. The extent of dissolution was enhanced by 20% on account of cocrystallization. The lornoxicam cocrystals were obtained with improved physicochemical characteristics.

Synthesis of Polyamidoamine Dendrimer for Encapsulating Tetramethylscutellarein for Potential Bioactivity Enhancement.

PubMed

Shadrack, Daniel M; Mubofu, Egid B; Nyandoro, Stephen S

2015-11-04

The biomedical potential of flavonoids is normally restricted by their low water solubility. However, little has been reported on their encapsulation into polyamidoamine (PAMAM) dendrimers to improve their biomedical applications. Generation four (G4) PAMAM dendrimer containing ethylenediaminetetraacetic acid core with acrylic acid and ethylenediamine as repeating units was synthesized by divergent approach and used to encapsulate a flavonoid tetramethylscutellarein (TMScu, 1) to study its solubility and in vitro release for potential bioactivity enhancement. The as-synthesized dendrimer and the dendrimer-TMScu complex were characterized by spectroscopic and spectrometric techniques. The encapsulation of 1 into dendrimer was achieved by a co-precipitation method with the encapsulation efficiency of 77.8% ± 0.69% and a loading capacity of 6.2% ± 0.06%. A phase solubility diagram indicated an increased water solubility of 1 as a function of dendrimer concentration at pH 4.0 and 7.2. In vitro release of 1 from its dendrimer complex indicated high percentage release at pH 4.0. The stability study of the TMScu-dendrimer at 0, 27 and 40 °C showed the formulations to be stable when stored in cool and dark conditions compared to those stored in light and warmer temperatures. Overall, PAMAM dendrimer-G4 is capable of encapsulating 1, increasing its solubility and thus could enhance its bioactivity.

Ratio of cyclase activating and cyclase inactive parathormone (CAP/CIP) in dialysis patients: correlations with other markers of bone disease.

PubMed

Grzegorzewska, A E; Młot, M

2004-01-01

We checked correlation of CAP/CIP with osteoprotegrin (OPG), its soluble ligand (OPGL) and routinely measured parameters of bone turnover in patients treated with peritoneal dialysis (PD) and hemodialysis (HD). In 30 patients (22 HD, 8 PD) we determined serum concentrations of intact parathormone (iPTH), CAP, OPG, OPGL, total Ca, inorganic phosphates (Pi), creatinine, urea, total alkaline phosphatase (AP) and blood pH. CIP was calculated by subtraction of CAP from iPTH. Controls (Cs) included 9 healthy persons in whom iPTH, CAP, OPG and OPGL were measured as well as CIP, CAP/CIP and OPGL/OPG were calculated. Differences between HD and PD patients included dialysis duration, OPGL, OPGL/OPG, AP, Pi, Ca and pH. After adjustment to dialysis duration differences in OPGL/OPG, Pi, Ca and pH remained significant. HD patients differed from Cs in terms of iPTH, CAP, CIP, OPGL, OPG and OPGL/OPG. In whole group of patients iPTH, CAP, CIP but not CAP/CIP correlated negatively with OPGL and OPGL/OPG as well as positively with dialysis duration, OPG and AP. Despite more advanced uremic bone disease in longer dialyzed HD patients than in shorter dialyzed PD ones, CAP/CIP is not different neither between these groups nor Cs persons. CAP/CIP does not seem to be more powerful tool in noninvasive diagnosis of bone disease than iPTH or CAP and CIP alone.

Heterogeneous electro-Fenton catalyst for 1-butylpyridinium chloride degradation.

PubMed

Meijide, Jessica; Pazos, Marta; Sanromán, Maria Ángeles

2017-10-15

The application of the electro-Fenton process for organic compound mineralisation has been widely reported over the past years. However, operational problems related to the use of soluble iron salt as a homogeneous catalyst involve the development of novel catalysts that are able to operate in a wide pH range. For this purpose, polyvinyl alcohol-alginate beads, containing goethite as iron, were synthesised and evaluated as heterogeneous electro-Fenton catalyst for 1-butylpyridinium chloride mineralisation. The influence of catalyst dosage and pH solution on ionic liquid degradation was analysed, achieving almost total oxidation after 60 min under optimal conditions (2 g/L catalyst concentration and pH 3). The results showed good catalyst stability and reusability, although its effectiveness decreases slightly after three successive cycles. Furthermore, a plausible mineralisation pathway was proposed based on the oxidation byproducts determined by chromatographic techniques. Finally, the Microtox® test revealed notable detoxification after treatment which demonstrates high catalyst ability for pyridinium-based ionic liquid degradation by the electro-Fenton process.

Impact of extractables from rubber closures on protein stability under heat stress.

PubMed

Richter, Carolin; Lipperheide, Cornelia; Lipke, Uwe; Lamprecht, Alf

2018-06-09

Commercially available, uncoated elastomeric closures were examined in regard to a potential contribution of extracted compounds from the rubber stoppers to protein aggregation under worst-case conditions. All rubber stoppers were confirmed to comply with Ph. Eur. quality requirements. Extraction with 2-propanol under reflux-conditions for 3 h led to closure-specific extraction profiles of the tested samples. One type of rubber stopper exhibited a considerably greater number and higher content of extractables. Four extracted compounds were identified as trialkyl benzene-1, 2, 4-tricarboxylates (trivial name: trimellitates), a substance class which is increasingly established as an alternative to phthalates. A highly concentrated aqueous solution of total extractables from this rubber stopper facilitated the formation of soluble and non-soluble high-molecular aggregates when incubated with model biopharmaceuticals (recombinant human immunoglobulin G (IgG) and recombinant erythropoietin (EPO)) under stress conditions (IgG: 60-64°C for 130 min, EPO: 55°C for 8 days). Furthermore, it was shown that the surfactant concentration (polysorbate 20, 0.1 m/v % vs. 1.0 m/v %) decisively influenced the formation of high-molecular aggregates. In case of EPO, the 10 fold increased concentration of surfactant was sufficient to prevent the aggregate formation completely. This study suggests the necessity of revisiting the current test system of Ph. Eur. monograph 3.2.9 for appropriate rubber stopper quality evaluation. Copyright © 2018. Published by Elsevier B.V.

Determination of hydroxytyrosol and tyrosol by liquid chromatography for the quality control of cosmetic products based on olive extracts.

PubMed

Miralles, Pablo; Chisvert, Alberto; Salvador, Amparo

2015-01-01

An analytical method for the simultaneous determination of hydroxytyrosol and tyrosol in different types of olive extract raw materials and cosmetic cream samples has been developed. The determination was performed by liquid chromatography with UV spectrophotometric detection. Different chromatographic parameters, such as mobile phase pH and composition, oven temperature and different sample preparation variables were studied. The best chromatographic separation was obtained under the following conditions: C18 column set at 35°C and isocratic elution of a mixture ethanol: 1% acetic acid solution at pH 5 (5:95, v/v) as mobile phase pumped at 1 mL min(-1). The detection wavelength was set at 280 nm and the total run time required for the chromatographic analysis was 10 min, except for cosmetic cream samples where 20 min runtime was required (including a cleaning step). The method was satisfactorily applied to 23 samples including solid, water-soluble and fat-soluble olive extracts and cosmetic cream samples containing hydroxytyrosol and tyrosol. Good recoveries (95-107%) and repeatability (1.1-3.6%) were obtained, besides of limits of detection values below the μg mL(-1) level. These good analytical features, as well as its environmentally-friendly characteristics, make the presented method suitable to carry out both the control of the whole manufacture process of raw materials containing the target analytes and the quality control of the finished cosmetic products. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of citric acid on metals mobility in pruning wastes and biosolids compost and metals uptake in Atriplex halimus and Rosmarinus officinalis.

PubMed

Tapia, Y; Eymar, E; Gárate, A; Masaguer, A

2013-05-01

To assess metal mobility in pruning waste and biosolids compost (pH 6.9 and total concentration of metals in milligram per kilogram of Cd 1.9, Cu 132, Fe 8,513, Mn 192, Pb 81, and Zn 313), shrubs species Atriplex halimus and Rosmarinus officinalis were transplanted in this substrate and irrigated with citric acid (4 g L(-1), pH 2.9) and nutrient solution daily for 60 days. Citric acid significantly increased the concentrations of soluble Mn and Fe in the nutrient substrate solution measured by suction probes, while other metals did not vary in concentration (Cu and Zn) or were not observed at detectable levels (Cd and Pb). In plants, citric acid significantly increased the concentrations of Cu (2.7 ± 0.1-3.3 ± 0.1 mg kg(-1)), Fe (49.2 ± 5.2-76.8 ± 6.8 mg kg(-1)), and Mn (7.2 ± 1.1-11.4 ± 0.7 mg kg(-1)) in leaves of R. officinalis, whereas the concentration of only Mn (25.4 ± 0.3-42.2 ± 2.9 mg kg(-1)) was increased in A. halimus. Increasing Fe and Mn solubility by citric acid addition indicates the possibility of using it to improve plant nutrition. The mobility of metals in this substrate was influenced for the concentration of the metal, the degree of humification of organic matter and its high Fe content.

Effects of ionised or chelated water-soluble mineral mixture supplementation on growth performance, nutrient digestibility, blood characteristics, meat quality and intestinal microbiota in broilers.

PubMed

Upadhaya, S D; Lee, B R; Kim, I H

2016-04-01

An experiment was conducted to study the effects of dietary supplementation of water-soluble ionised or chelated mineral mixture on growth performance, nutrient digestibility, blood characteristics, relative organ weight, meat quality and excreta microflora in broilers. A total of 408 Arbor Acres broilers (17 birds in 8 replicate pens) were randomly allocated into one of the following three treatments: (1) Control/basal diet (CON), (2) T1 (basal diet + 0.5% ionised mineral mixture solution, pH 3.0) and (3) T2 (basal diet + 0.5% chelated mineral mixture solution, pH 3.0). The body weight gain was greater and feed conversion ratio was lower in broilers supplemented with ionised or chelated mineral liquid complex compared to CON during the grower and overall phase of the experiment. No significant effect in the concentration of Ca and P in the blood was observed in birds supplemented with ionised or chelated mineral mixture solution. No adverse effects were observed in organ weight and meat quality with ionised or chelated mineral mixture supplementation. Regarding intestinal microbiota counts there was a reduction of Escherichia coli counts in the small intestine in ionised mineral supplemented birds. In the large intestine, E. coli as well as Salmonella populations were reduced in ionised mineral supplemented birds. In conclusion, ionised or chelated minerals have partial positive effects in improving growth performance and reducing pathogenic bacteria load in the gastro-intestinal tract.

Investigation of the tracers for plastic-enriched waste burning aerosols

NASA Astrophysics Data System (ADS)

Kumar, Sudhanshu; Aggarwal, Shankar G.; Gupta, Prabhat K.; Kawamura, Kimitaka

2015-05-01

To better identify the tracers for open-waste burning (OWB) aerosols, we have conducted aerosol sampling at 2 landfill sites, i.e., Okhla and Bhalswa in New Delhi. The metals such as, As, Cd, Sb and Sn, which have been observed almost negligible in remote aerosols, are found abundantly in these OWB aerosol samples (n = 26), i.e., 60 ± 65, 41 ± 53, 537 ± 847 and 1325 ± 1218 ng m-3, respectively. Samples (n = 20) collected at urban locations in New Delhi, i.e., at Employees' State Insurance (ESI) hospital and National Physical Laboratory (NPL) also show high abundances of these metals in the particles. Filter samples are also analyzed for water-soluble dicarboxylic acids (C2-C12) and related compounds (oxocarboxylic acids and α-dicarbonyls). Terephthalic acid (tPh) was found to account for more than 77% of total diacids determined in OWB aerosols. However, such a high abundance of tPh is not observed in aerosols collected at urban sites. Instead, phthalic acid (Ph) was found as the third/fourth most abundant diacid (∼3%) following C2 (>70%) and C4 (>12%) in these waste burning influenced urban aerosols. A possible secondary formation pathway of Ph by photo-degradation of phthalate ester (di-2-ethylhexyl phthalate) in plastic-waste burning aerosol is suggested. Ionic composition of OWB aerosols showed that Cl- is the most abundant ion (40 ± 8% of total ions determined). The correlation studies of the potential metals with the organic tracers of garbage burning, i.e., phthalic, isophthalic and terephthalic acids show that especially Sn can be used as marker for tracing the plastic-enriched waste burning aerosols.

Size-Controlled Dissolution of Organic-Coated Silver Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Rui; Levard, Clément; Marinakos, Stella M.

2012-04-02

The solubility of Ag NPs can affect their toxicity and persistence in the environment. We measured the solubility of organic-coated silver nanoparticles (Ag NPs) having particle diameters ranging from 5 to 80 nm that were synthesized using various methods, and with different organic polymer coatings including poly(vinylpyrrolidone) and gum arabic. The size and morphology of Ag NPs were characterized by transmission electron microscopy (TEM). X-ray absorption fine structure (XAFS) spectroscopy and synchrotron-based total X-ray scattering and pair distribution function (PDF) analysis were used to determine the local structure around Ag and evaluate changes in crystal lattice parameters and structure asmore » a function of NP size. Ag NP solubility dispersed in 1 mM NaHCO{sub 3} at pH 8 was found to be well correlated with particle size based on the distribution of measured TEM sizes as predicted by the modified Kelvin equation. Solubility of Ag NPs was not affected by the synthesis method and coating as much as by their size. Based on the modified Kelvin equation, the surface tension of Ag NPs was found to be {approx}1 J/m{sup 2}, which is expected for bulk fcc (face centered cubic) silver. Analysis of XAFS, X-ray scattering, and PDFs confirm that the lattice parameter, {alpha}, of the fcc crystal structure of Ag NPs did not change with particle size for Ag NPs as small as 6 nm, indicating the absence of lattice strain. These results are consistent with the finding that Ag NP solubility can be estimated based on TEM-derived particle size using the modified Kelvin equation for particles in the size range of 5-40 nm in diameter.« less

Yogurt made from milk heated at different pH values.

PubMed

Ozcan, Tulay; Horne, David S; Lucey, John A

2015-10-01

Milk for yogurt manufacture is subjected to high heat treatment to denature whey proteins. Low milk pH values (≤ 6.5) at heating result in most denatured whey proteins becoming associated with casein micelles, whereas high milk pH values (≥ 7.0) at heating result in the formation of mostly soluble (nonmicellar) denatured whey protein complexes. There are conflicting reports on the relative importance of soluble and casein-bound whey protein aggregates on the properties of acid gels. Prior studies investigating the effect of pH of milk at heating used model gels in which milk was acidified by glucono-δ-lactone; in this study, we prepared yogurt gels using commercial starter cultures. Model acid gels can have very different texture and physical properties from those made by fermentation with starter cultures. In this study, we investigated the effects of different pH values of milk at heating on the rheological, light backscatter, and microstructural properties of yogurt gels. Reconstituted skim milk was adjusted to pH values 6.2, 6.7, and 7.2 and heated at 85°C for 30 min. A portion of the heated milk samples was readjusted back to pH 6.7 after heating. Milks were inoculated with 3% (wt/wt) yogurt starter culture and incubated at 40°C until pH 4.6. Gel formation was monitored using dynamic oscillatory rheology, and parameters measured included the storage modulus (G') and loss tangent (LT) values. Light-backscattering properties, such as the backscatter ratio (R) and the first derivative of light backscatter ratio (R'), were also monitored during fermentation. Fluorescence microscopy was used to observe gel microstructure. The G' values at pH 4.6 were highest in gels made from milk heated at pH 6.7 and lowest in milk heated at pH 6.2, with or without pH adjustment after heating. The G' values at pH 4.6 were lower in samples after adjustment back to pH 6.7 after heating. No maximum in the LT parameter was observed during gelation for yogurts made from milk heated at pH 6.2; a maximum in LT was observed at pH ~4.8 for samples heated at pH 6.7 or 7.2, with or without pH adjustment after heating. Higher R-values were observed with an increase in pH of heating, with or without pH adjustment after heating. The sample heated at pH 6.2 had only one major peak in its R' profile during acidification, whereas samples heated at pH 6.7 and 7.2 had 2 large peaks. The lack of a maximum in LT parameter and the presence of a single peak in the R' profile for the samples heated at pH 6.2 were likely due to the partial solubilization of insoluble calcium phosphate when milk was acidified to this lower pH value. No clear differences were observed in the microstructures of gels between the different treatments. This study indicates that heating milk at the natural pH (~6.7) created an optimum balance of casein-bound and soluble denatured whey proteins, which resulted in yogurt with the highest gel stiffness. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Models analyses for allelopathic effects of chicory at equivalent coupling of nitrogen supply and pH level on F. arundinacea, T. repens and M. sativa.

PubMed

Wang, Quanzhen; Xie, Bao; Wu, Chunhui; Chen, Guo; Wang, Zhengwei; Cui, Jian; Hu, Tianming; Wiatrak, Pawel

2012-01-01

Alllelopathic potential of chicory was investigated by evaluating its effect on seed germination, soluble sugar, malondialdehyde (MDA) and the chlorophyll content of three target plants species (Festuca arundinacea, Trifolium repens and Medicago sativa). The secretion of allelochemicals was regulated by keeping the donor plant (chicory) separate from the three target plant species and using different pH and nitrogen levels. Leachates from donor pots with different pH levels and nitrogen concentrations continuously irrigated the target pots containing the seedlings. The allelopathic effects of the chicory at equivalent coupling of nitrogen supply and pH level on the three target plants species were explored via models analyses. The results suggested a positive effect of nitrogen supply and pH level on allelochemical secretion from chicory plants. The nitrogen supply and pH level were located at a rectangular area defined by 149 to 168 mg/l nitrogen supply combining 4.95 to 7.0 pH value and point located at nitrogen supply 177 mg/l, pH 6.33 when they were in equivalent coupling effects; whereas the inhibitory effects of equivalent coupling nitrogen supply and pH level were located at rectangular area defined by 125 to 131 mg/l nitrogen supply combining 6.71 to 6.88 pH value and two points respectively located at nitrogen supply 180 mg/l with pH 6.38 and nitrogen supply 166 mg/l with pH 7.59. Aqueous extracts of chicory fleshy roots and leaves accompanied by treatment at different sand pH values and nitrogen concentrations influenced germination, seedling growth, soluble sugar, MDA and chlorophyll of F. arundinacea, T. repens and M. sativa. Additionally, we determined the phenolics contents of root and leaf aqueous extracts, which were 0.104% and 0.044% on average, respectively.

Models Analyses for Allelopathic Effects of Chicory at Equivalent Coupling of Nitrogen Supply and pH Level on F. arundinacea, T. repens and M. sativa

PubMed Central

Wang, Quanzhen; Xie, Bao; Wu, Chunhui; Chen, Guo; Wang, Zhengwei; Cui, Jian; Hu, Tianming; Wiatrak, Pawel

2012-01-01

Alllelopathic potential of chicory was investigated by evaluating its effect on seed germination, soluble sugar, malondialdehyde (MDA) and the chlorophyll content of three target plants species (Festuca arundinacea, Trifolium repens and Medicago sativa). The secretion of allelochemicals was regulated by keeping the donor plant (chicory) separate from the three target plant species and using different pH and nitrogen levels. Leachates from donor pots with different pH levels and nitrogen concentrations continuously irrigated the target pots containing the seedlings. The allelopathic effects of the chicory at equivalent coupling of nitrogen supply and pH level on the three target plants species were explored via models analyses. The results suggested a positive effect of nitrogen supply and pH level on allelochemical secretion from chicory plants. The nitrogen supply and pH level were located at a rectangular area defined by 149 to 168 mg/l nitrogen supply combining 4.95 to 7.0 pH value and point located at nitrogen supply 177 mg/l, pH 6.33 when they were in equivalent coupling effects; whereas the inhibitory effects of equivalent coupling nitrogen supply and pH level were located at rectangular area defined by 125 to 131 mg/l nitrogen supply combining 6.71 to 6.88 pH value and two points respectively located at nitrogen supply 180 mg/l with pH 6.38 and nitrogen supply 166 mg/l with pH 7.59. Aqueous extracts of chicory fleshy roots and leaves accompanied by treatment at different sand pH values and nitrogen concentrations influenced germination, seedling growth, soluble sugar, MDA and chlorophyll of F. arundinacea, T. repens and M. sativa. Additionally, we determined the phenolics contents of root and leaf aqueous extracts, which were 0.104% and 0.044% on average, respectively. PMID:22384054

Method to separate lignin-rich solid phase from acidic biomass suspension at an acidic pH

DOEpatents

Yasarla, Kumar Lakshmi Rakesh; Ramarao, Bandaru V; Amidon, Thomas

2017-09-05

A method of separating a lignin-rich solid phase from a solution suspension, by pretreating a lignocellulosic biomass with a pretreatment fluid having remove soluble components, colloidal material and primarily lignin containing particles; separating the pretreated lignocellulosic biomass from the pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles; flocculating the separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles using polyethylene oxide (i.e., PEO) or cationic Poly acrylamide (i.e., CPAM) as a flocculating agent; and filtering the flocculated separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles to remove agglomerates.

Properties of whey protein isolates extruded under acidic and alkaline conditions.

PubMed

Onwulata, C I; Isobe, S; Tomasula, P M; Cooke, P H

2006-01-01

Whey proteins have wide acceptance and use in many products due to their beneficial nutritional properties. To further increase the amount of whey protein isolates (WPI) that may be added to products such as extruded snacks and meats, texturization of WPI is necessary. Texturization changes the folding of globular proteins to improve interaction with other ingredients and create new functional ingredients. In this study, WPI pastes (60% solids) were extruded in a twin-screw extruder at 100 degrees C with 4 pH-adjusted water streams: acidic (pH 2.0 +/- 0.2) and alkaline (pH 12.4 +/- 0.4) streams from 2 N HCl and 2 N NaOH, respectively, and acidic (pH 2.5 +/- 0.2) and alkaline (pH 11.5 +/- 0.4) electrolyzed water streams; these were compared with WPI extruded with deionized water. The effects of water acidity on WPI solubility at pH 7, color, microstructure, Rapid Visco Analyzer pasting properties, and physical structure were determined. Alkaline conditions increased insolubility caused yellowing and increased pasting properties significantly. Acidic conditions increased solubility and decreased WPI pasting properties. Subtle structural changes occurred under acidic conditions, but were more pronounced under alkaline conditions. Overall, alkaline conditions increased denaturation in the extruded WPI resulting in stringy texturized WPI products, which could be used in meat applications.

Effect of pH values on surface modification and solubility of phosphate bioglass-ceramics in the CaO-P 2O 5-Na 2O-SrO-ZnO system

NASA Astrophysics Data System (ADS)

Li, Xudong; Cai, Shu; Zhang, Wenjuang; Xu, Guohua; Zhou, Wei

2009-08-01

The bioactive glass-ceramics in the CaO-P 2O 5-Na 2O-SrO-ZnO system were synthesized by the sol-gel technique, and then chemically treated at different pH values to study the solubility and surface modification. Samples sintered at 650 °C for 4 h consisted of the crystalline phase β-Ca 2P 2O 7 and the glass matrix. After soaking in the solution at pH 1.0, the residual glass matrix on the surface appeared entirely dissolved and no new phase could be detected. Whereas at pH 3.0, web-like layer exhibiting peaks corresponding to CaP 2O 6 was formed and covered the entire surface of the sample. When conducted at pH 10.0, only part of the glass matrix was dissolved and a new phase Ca 4P 6O 19 was precipitated, forming the petaline layer. The chemical treatment can easily change the surface morphologies and phase composition of this bioactive glass-ceramics. The higher level of surface roughness resulting from the new-formed layer would improve the interface bonding and benefit for cell adhesion.

Role of individual histidines in the pH-dependent global stability of human chloride intracellular channel 1.

PubMed

Achilonu, Ikechukwu; Fanucchi, Sylvia; Cross, Megan; Fernandes, Manuel; Dirr, Heini W

2012-02-07

Chloride intracellular channel proteins exist in both a soluble cytosolic form and a membrane-bound form. The mechanism of conversion between the two forms is not properly understood, although one of the contributing factors is believed to be the variation in pH between the cytosol (~7.4) and the membrane (~5.5). We systematically mutated each of the three histidine residues in CLIC1 to an alanine at position 74 and a phenylalanine at positions 185 and 207. We examined the effect of the histidine-mediated pH dependence on the structure and global stability of CLIC1. None of the mutations were found to alter the global structure of the protein. However, the stability of H74A-CLIC1 and H185F-CLIC1, as calculated from the equilibrium unfolding data, is no longer dependent on pH because similar trends are observed at pH 7.0 and 5.5. The crystal structures show that the mutations result in changes in the local hydrogen bond coordination. Because the mutant total free energy change upon unfolding is not different from that of the wild type at pH 7.0, despite the presence of intermediates that are not seen in the wild type, we propose that it may be the stability of the intermediate state rather than the native state that is dependent on pH. On the basis of the lower stability of the intermediate in the H74A and H185F mutants compared to that of the wild type, we conclude that both His74 and His185 are involved in triggering the pH changes to the conformational stability of wild-type CLIC1 via their protonation, which stabilizes the intermediate state.

Simultaneous separation of water- and fat-soluble vitamins in isocratic pressure-assisted capillary electrochromatography using a methacrylate-based monolithic column.

PubMed

Yamada, Hiroki; Kitagawa, Shinya; Ohtani, Hajime

2013-06-01

A method of simultaneous separation of water- and fat-soluble vitamins using pressure-assisted CEC with a methacrylate-based capillary monolithic column was developed. In the proposed method, water-soluble vitamins were mainly separated electrophoretically, while fat soluble-ones were separated chromatographically by the interaction with a methacrylate-based monolith. A mixture of six water-soluble and four fat-soluble vitamins was separated simultaneously within 20 min with an isocratic elution using 1 M formic acid (pH 1.9)/acetonitrile (30:70, v/v) containing 10 mM ammonium formate as a mobile phase. When the method was applied to a commercial multivitamin tablet and a spiked one, the vitamins were successfully analyzed, and no influence of the matrix contained in the tablet was observed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improvement of the solubilization of proteins in two-dimensional electrophoresis with immobilized pH gradients

PubMed Central

Rabilloud, Thierry; Adessi, C.; Giraudel, A.; Lunardi, J.

2007-01-01

Summary We have carried out the separation of sparingly-soluble (membrane and nuclear) proteins by high resolution two-dimensional electrophoresis. IEF with immobilized pH gradients leads to severe quantitative losses of proteins in the resulting 2-D map, although the resolution is usually kept high. We therefore tried to improve the solubility of proteins in this technique, by using denaturing cocktails containing various detergents and chaotropes. Best results were obtained by using a denaturing solution containing urea, thiourea, and detergents (both nonionic and zwitterionic). The usefulness of thiourea-containing denaturing mixtures are shown in this article on several models including microsomal and nuclear proteins and on tubulin, a protein highly prone to aggregation. PMID:9150907

Baclofen Solution for Low-Volume Therapeutic Delivery.

PubMed

Meythaler, Jay M; Peduzzi, Jean D

2017-06-01

Baclofen is a zwitterion molecule where increased ions in the excipient increase the solubility. We developed baclofen in a stable solution similar to cerebrospinal fluid (CSF) without bicarbonate and proteins to improve the solubility of the baclofen and to reduce the potential toxicity to the central nervous system (CNS) and subarachnoid space. The objective is to develop a solution of baclofen wherein baclofen is solubilized in a multivalent physiological ion solution such as artificial cerebrospinal fluid (aCSF) at a concentration from 2 mg/cc to 10 mg/cc. First, to determine the solubility of Baclofen in aCSF, solubility was determined at six different pH levels at 37°C, by the addition of aCSF to a known amount of Baclofen. The final concentrations were confirmed by high performance liquid chromatography (HPLC) analysis. Second, the stability of Baclofen at 4 mg/cc investigated in a test manufacturing batch utilizing standard methods of production of 1500 20 cc vials inverted for 18 months at 25°C at 60% humidity. The stability and purity of the baclofen was verified at 18 months by HPLC analysis. Baclofen was initially soluble between pH of 6-8 above 7 mg/cc but fell back to 6.3-5.8 mg/cc level with time. Baclofen produced in vials with inversion were noted to be stable at 4 mg/cc at 18 months with less than 2% breakdown of the baclofen in solution. Baclofen is much more soluble in artificial CSF than normal saline. The artificial CSF may also be less toxic to the subarachnoid space than saline. © 2016 International Neuromodulation Society.

Fluidized Bed Hot-Melt Granulation as a Tool to Improve Curcuminoid Solubility.

PubMed

Teixeira, Cristiane C C; de Paiva Junior, Elias; de Freitas, Luis Alexandre Pedro

2018-04-01

Curcumin is the main bioactive component of Curcuma longa L. and has recently aroused growing interest from the scientific community. Unfortunately, the medicinal properties attributed to curcuminoids are impaired by their low oral bioavailability or low solubility in aqueous solutions. Many strategies have been studied to improve curcumin solubility; however, the preparation of granules using hydrophilic materials has never been attempted. The aim of this work was to develop curcumin granules by fluidized bed hot-melt granulation using the hydrophilic carrier Gelucire® 50:13. A two-level factorial design was used to verify the influence of Gelucire® 50:13 and lactose contents found in the granules on their size, morphology, bulk and tapped densities, flow, moisture content, and water activity. The granules obtained were also evaluated by differential scanning calorimetry, thermogravimetric analysis, X-ray powder diffraction, and infrared spectrometry. The curcumin solubility and dissolution rates in water were determined by liquid chromatography. The best formulation provides an increase of curcumin solubility of 4642-fold and 3.8-fold compared to the physical mixture. The dissolution tests showed a maximum drug release from granules after 45 min of 70% at pH 1.2 and 80% at pH 5.8 and 7.4, while for non-granulated curcumin, the release was below 20% in all pH. The solid-state characterization and solubility measurement showed good stability of granules over 9 months. The results attest that the fluidized bed hot-melt granulation with hydrophilic binders is an attractive and promising alternative to obtain solid forms of curcumin with enhanced bioavailability.

Comparison of the aggregation of homologous β2-microglobulin variants reveals protein solubility as a key determinant of amyloid formation.

PubMed

Pashley, Clare L; Hewitt, Eric W; Radford, Sheena E

2016-02-13

The mouse and human β2-microglobulin protein orthologs are 70% identical in sequence and share 88% sequence similarity. These proteins are predicted by various algorithms to have similar aggregation and amyloid propensities. However, whilst human β2m (hβ2m) forms amyloid-like fibrils in denaturing conditions (e.g. pH2.5) in the absence of NaCl, mouse β2m (mβ2m) requires the addition of 0.3M NaCl to cause fibrillation. Here, the factors which give rise to this difference in amyloid propensity are investigated. We utilise structural and mutational analyses, fibril growth kinetics and solubility measurements under a range of pH and salt conditions, to determine why these two proteins have different amyloid propensities. The results show that, although other factors influence the fibril growth kinetics, a striking difference in the solubility of the proteins is a key determinant of the different amyloidogenicity of hβ2m and mβ2m. The relationship between protein solubility and lag time of amyloid formation is not captured by current aggregation or amyloid prediction algorithms, indicating a need to better understand the role of solubility on the lag time of amyloid formation. The results demonstrate the key contribution of protein solubility in determining amyloid propensity and lag time of amyloid formation, highlighting how small differences in protein sequence can have dramatic effects on amyloid formation. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Toxicity of the molybdate anion in soil is partially explained by effects of the accompanying cation or by soil pH.

PubMed

Buekers, Jurgen; Mertens, Jelle; Smolders, Erik

2010-06-01

Previous studies have shown that toxicity of cationic trace metals in soil is partially confounded by effects of the accompanying anions. A similar assessment is reported here for toxicity of an oxyanion, i.e., molybdate (MoO(4) (2-)), the soil toxicity of which is relatively unexplored. Solubility and toxicity were compared between the soluble sodium molybdate (Na(2)MoO(4)) and the sparingly soluble molybdenum trioxide (MoO(3)). Confounding effects of salinity were excluded by referencing the Na(2)MoO(4) effect to that of sodium chloride (NaCl). The pH decrease from the acid MoO(3) amendment was equally referenced to a hydrochloric (HCl) treatment or a lime-controlled MoO(3) treatment. The concentrations of molybdenum (Mo) in soil solution or calcium chloride (CaCl(2)) 0.01 M extracts were only marginally affected by either MoO(3) or Na(2)MoO(4) as an Mo source after 10 to 13 days of equilibration. Effects of Mo on soil nitrification were fully confounded by associated changes in salinity or pH. Effects of Mo on growth of wheat seedlings (Triticum aestivum L) were more pronounced than those on nitrification, and toxicity thresholds were unaffected by the form of added Mo. The Mo thresholds for wheat growth were not confounded by pH or salinity at incipient toxicity. It is concluded that oxyanion toxicity might be confounded in relatively insensitive tests for which reference treatments should be included. Copyright 2010 SETAC.

Water selenium speciation and sediment fractionation in a California flow-through wetland system

USGS Publications Warehouse

Gao, S.; Tanii, K.K.; Peters, D.W.; Herbel, M.J.

2000-01-01

A flow-through wetland system was established in the Tulare Lake Drainage District (TLDD) in California to determine if selenium (Se) from saline irrigation drainage can be removed prior to impoundment in evaporation basins to reduce potential toxicity to waterbirds. The objective of this research was to evaluate Se speciation, accumulation, and fractionation in the waters and sediments of the newly developed wetland system. The inlet water was dominated by selenate [Se(VI), 92%], with smaller percentages of selenite [Se(IV), 5%] and organic Se [org-Se(-II), 3%]. For the outflow water, the average percentage of Se(VI) was 72% in November 1997 and 59% in February 1999. This change may be due to an increase in either residence time and/or accumulation of organic detrital matter, which may enhance Se(VI) reduction processes. Selenium accumulation, transformation, and incorporation with the solid phase were all intensified in the surface sediment (<20 cm). The highest total Se concentrations in the sediments were found in the top 5 cm and concentrations dramatically decreased with depth. Elemental Se [Se(0)], as extracted by Na2SO3, was the largest fraction (average of 46%) of the total sediment Se, followed by organic matter-associated Se (OM-Se) extracted by NaOH (average of 34%). Soluble, adsorbed, and carbonate-associated Se, as extracted by KCl, K2HPO4 (pH 8.0), and NaOAc (pH 5.0), were about 3, 10, and 3% of the total sediment Se, respectively. After establishing the wetland for 2 yr, significant Se removal from the flowing water was observed. The major sink mechanisms in the sediment are reduction to Se(0) and immobilization into the organic phase.A flow-through wetland system was established in the Tulare Lake Drainage District (TLDD) in California to determine if selenium (Se) from saline irrigation drainage can be removed prior to impoundment in evaporation basins to reduce potential toxicity to waterbirds. The objective of this research was to evaluate Se speciation, accumulation, and fractionation in the waters and sediments of the newly developed wetland system. The inlet water was dominated by selenate [Se(VI), 92%], with smaller percentages of selenite [Se(IV), 5%] and organic Se [org-Se(-II), 3%]. For the outflow water, the average percentage of Se(VI) was 72% in November 1997 and 59% in February 1999. This change may be due to an increase in either residence time and/or accumulation of organic detrital matter, which may enhance Se(VI) reduction processes. Selenium accumulation, transformation, and incorporation with the solid phase were all intensified in the surface sediment (<20 cm). The highest total Se concentrations in the sediments were found in the top 5 cm and concentrations dramatically decreased with depth. Elemental Se [Se(0)], as extracted by Na2SO3, was the largest fraction (average of 46%) of the total sediment Se, followed by organic matter-associated Se (OM-Se) extracted by NaOH (average of 34%). Soluble, adsorbed, and carbonate-associated Se, as extracted by KCl, K2HPO4 (pH 8.0), and NaOAc (pH 5.0), were about 3, 10, and 3% of the total sediment Se, respectively. After establishing the wetland for 2 yr, significant Se removal from the flowing water was observed. The major sink mechanisms in the sediment are reduction to Se(0) and immobilization into the organic phase.

Use of acidifier and solubilizer in tadalafil solid dispersion to enhance the in vitro dissolution and oral bioavailability in rats.

PubMed

Choi, Jin-Seok; Kwon, Soon-Hyung; Lee, Sang-Eun; Jang, Woo Suk; Byeon, Jong Chan; Jeong, Hyeong Mo; Park, Jeong-Sook

2017-06-30

The purpose of this study is to improve the solubility, in vitro dissolution, and oral bioavailability in rats of tadalafil (TDF) by using SD technique with a weak acid and a copolymer. TDF-SD was prepared via solvent evaporation, coupled with the incorporation of an acidifier and solubilizer. Tartaric acid enhanced the solubility of TDF over 5-fold in DW, and Soluplus ® enhanced the solubility of TDF over 8.7-fold and 19.2-fold compared to that of TDF (pure) in DW and pH 1.2 for 1h, respectively. The optimal formulation of TDF-SD3 was composed of TDF vs Tartaric acid vs Soluplus ® vs Aerosil=1:1:3:3. The in vitro dissolution rate of TDF-SD3 in DW, pH 1.2 and pH 6.8 buffer (51.5%, 53.3%, and 33.2%, respectively) was significantly higher than that of the commercial product (Cialis ® ) powder (16.5%, 15.2%, and 14.8%, respectively). TDF was completely transformed to an amorphous form as shown in SEM, DSC and PXRD data. The stability of TDF-SD3 included drug contents and in vitro dissolution for 1 month were similar to those of Cialis ® , and the amorphous form of TDF-SD3 was well maintained for 6 months. The TDF-SD3 formulation improved the relative bioavailability (BA) and peak plasma concentration (C max ) compared to that of Cialis ® powder after oral administration in rats as 117.3% and 135.7%, respectively. From the results, we found that the acidifier increased the wettability of TDF, and the solubilizer improved solubility through hydrogen bonding with TDF, thereby increasing the solubility, dissolution and oral bioavailability of TDF in TDF-SD3. Copyright © 2017 Elsevier B.V. All rights reserved.

Consumer acceptance of orange juice mixed with water mint leave extract.

PubMed

Ali, Marwa Rashad

2017-10-31

Orange-Mint leaves juice was formulated using different addition percentages of mint leaves extract. The juice was aseptically processed, packed in glass bottles under sterilized environment and sterilized at 70°C for 15 minutes then storage at 5°C for 3 months. The physicochemical, nutritional value, microbiological and sensory characteristics of the juice was evaluated. There is no difference in pH, total soluble solids, ash, and total acidity in all samples moreover, the sample A2, "orange juice with 15% of mint leaves extract" recorded the best values of sensory evaluation, on the other hand, it was recorded lower values of vitamin C and total phenolic compound than sample (C) or (C1) because of increasing in addition% of mint leaves extract to orange juice. The sensory properties of juice samples were not remarkable any changes during storage. The result indicated that the juice was acceptable up to 3 months of storage 5°C. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Rubus fruticosus (blackberry) use as an herbal medicine

PubMed Central

Verma, Rameshwar; Gangrade, Tushar; Punasiya, Rakesh; Ghulaxe, Chetan

2014-01-01

Wild grown European blackberry Rubus fruticosus) plants are widespread in different parts of northern countries and have been extensively used in herbal medicine. The result show that European blackberry plants are used for herbal medicinal purpose such as antimicrobial, anticancer, antidysentery, antidiabetic, antidiarrheal, and also good antioxidant. Blackberry plant (R. fruticosus) contains tannins, gallic acid, villosin, and iron; fruit contains vitamin C, niacin (nicotinic acid), pectin, sugars, and anthocyanins and also contains of berries albumin, citric acid, malic acid, and pectin. Some selected physicochemical characteristics such as berry weight, protein, pH, total acidity, soluble solid, reducing sugar, vitamin C, total antioxidant capacity, antimicrobial screening of fruit, leaves, root, and stem of R. fruticosus, and total anthocyanins of four preselected wild grown European blackberry (R. fruticosus) fruits are investigated. Significant differences on most of the chemical content detect among the medicinal use. The highest protein content (2%), the genotypes with the antioxidant activity of standard butylated hydroxyanisole (BHA) studies 85.07%. Different cultivars grown in same location consistently show differences in antioxidant capacity. PMID:25125882

Evaluation of Antioxidant Compounds and Total Sugar Content in a Nectarine [Prunus persica (L.) Batsch] Progeny

PubMed Central

Abidi, Walid; Jiménez, Sergio; Moreno, María Ángeles; Gogorcena, Yolanda

2011-01-01

Epidemiological studies suggest that consumption of fruit rich in phenolic compounds is associated with health-protective effects due to their antioxidant properties. For these reasons quality evaluation has become an important issue in fruit industry and in breeding programs. Phytochemical traits such as total phenolics, flavonoids, anthocyanins, L-ascorbic acid, sugar content and relative antioxidant capacity (RAC) were analyzed over four years in flesh fruit of an F1 population “Venus” × “Big Top” nectarines. Other traits such as harvesting date, yield, fruit weight, firmness, soluble solids concentration (SSC), pH, titratable acidity (TA) and ripening index (RI) were also determined in the progeny. Results showed high variability among genotypes for all analyzed traits. Total phenolics and flavonoids showed significant positive correlations with RAC implying that both are important antioxidant bioactive compounds in peaches. We found genotypes with enhanced antioxidant capacity and a better performance than progenitors, and in consequence the best marketability. PMID:22072927

Chemical and sensory quality of fresh pomegranate fruits exposed to gamma radiation as quarantine treatment.

PubMed

Shahbaz, Hafiz Muhammad; Ahn, Jae-Jun; Akram, Kashif; Kim, Hyo-Young; Park, Eun-Joo; Kwon, Joong-Ho

2014-02-15

The U.S. Department of Agriculture in February 2012 approved the import of fresh pomegranates subjected to irradiation as a quarantine procedure with a minimum absorbed dose of 0.4kGy against different pests. This study evaluated the application of different gamma-irradiation doses (0.4, 1, and 2kGy) in fresh pomegranate fruits and their effect on the chemical and sensory characteristics. The total soluble solids, titratable acidity, and pH values remained unaffected up to 1kGy treatment. Irradiation caused a significant decrease in the total anthocyanins and phenolic content. A strong positive correlation was observed among the antioxidant activities, total phenolics and anthocyanin contents. In general, a stronger preference was shown by sensory panelists for the juice from irradiated fruits. This study provides research-based information about the application of irradiation as a quarantine disinfestation treatment to enhance the marketing and consumer acceptance of pomegranates. Copyright © 2013 Elsevier Ltd. All rights reserved.