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Deborah D.l. Chung - One of the best experts on this subject based on the ideXlab platform.
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Pore Structure and Permeability of an Alumina Fiber Filter Membrane for Hot Gas Filtration
Journal of Porous Materials, 2002Co-Authors: J. A. Fernando, Deborah D.l. ChungAbstract:The pore structure and permeability of an alumina-fiber-based hot gas filter membrane containing an Acid Phosphate binder were characterized using capillary flow porometry. The smallest pore diameter was 1.24 ± 0.06 μm; the largest pore diameter (bubble point pore diameter) was 23 ± 1 μm. The pore size distribution was narrow, with almost all pores ranging from 2 to 4 μm, and the mean flow pore size 2.6 ± 0.1 μm. The Darcy permeability constant for air through the membrane was (114 ± 6) × 10^−9 cm^2.
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Improving an alumina fiber filter membrane for hot gas filtration using an Acid Phosphate binder
Journal of Materials Science, 2001Co-Authors: J. A. Fernando, Deborah D.l. ChungAbstract:Alumina fiber based filter membranes were prepared using Acid Phosphate (phosphoric Acid plus aluminum hydroxide), colloidal alumina, monoaluminum Phosphate and three types of colloidal silica binders at various binders contents. The filter membranes containing between 5% and 10% by weight of Acid Phosphate binder exhibited the highest flexural strength, compressive strength, work of fracture and elastic modulus in comparison to those containing the other binders at equivalent binder contents, and exhibited the lowest pressure drop in comparison to membranes with other binders and having equivalent flexural and compressive strengths. Microscopy showed that the Acid Phosphate caused the fibers to bond at their junctions only, whereas colloidal alumina or colloidal silica binders caused free binder particles within the fiber network.
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improvement of the temperature resistance of aluminium matrix composites using an Acid Phosphate binder part iii aluminium matrix composites
Journal of Materials Science, 1993Co-Authors: Jeng Maw Chiou, Deborah D.l. ChungAbstract:The use of Phosphate binders instead of the widely used silica binder resulted in improved temperature resistance, increased tensile strength and decreased coefficient of thermal expansion. The effects were largest for the Phosphate binder which contained the largest amount of phosphoric Acid (P/Al atom ratio=24 in the liquid binder). These effects were probably due to the protection of the SiC whiskers by the binder phases (aluminium metaPhosphate or aluminium orthoPhosphate), the binder-SiC reaction product (SiP 2 O 7 ) and the binder-aluminium reaction product (AlP) from further reaction between the SiC and aluminium
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Improvement of the temperature resistance of aluminium-matrix composites using an Acid Phosphate binder
Journal of Materials Science, 1993Co-Authors: Jeng Maw Chiou, Deborah D.l. ChungAbstract:Binders are used in preforms from which metal-matrix composites are fabricated by liquid-metal infiltration. This paper (Part I) reports the preparation and characterization of various binders (by themselves). The characterization was in terms of the composition (by atomic absorption spectrometry and X-ray spectrometry), morphology, phases (by X-ray diffraction) and changes upon heating to 1200 °C (by thermogravimetric analysis and mass spectrometry). The binders studied include silica, Phosphates (prepared from Al (OH)_3 and H_3PO_4) with the P/Al molar ratio ranging from 1–23, sodium silicate and acrylic emulsion. A Phosphate binder was in the form of type B aluminium metaPhosphate (Al(PO_3)_3) at 500 °C when the P/Al atom ratio = 2.2 in the liquid binder, and was in the form of type A aluminium metaPhosphate (Al/(PO_3)_3) when the atom ratio ≥ 5.8 in the liquid binder. Most of the Phosphate binders formed type A aluminium metaPhosphate (Al(PO_3)_3) after heat treatment at 800 °C. The Phosphate binder with P/Al atom ratio = 2.2 in the liquid binder formed cristobalite aluminium orthoPhosphate (AlPO_4), and the Phosphate binder with P/Al atom ratio = 24 in the liquid binder formed a combination of cristobalite aluminium orthoPhosphate (AlPO_4) and metaPhosphate glass after heat treatment at 1200 °C in argon.
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Improvement of the temperature resistance of aluminium-matrix composites using an Acid Phosphate binder
Journal of Materials Science, 1993Co-Authors: Jeng Maw Chiou, Deborah D.l. ChungAbstract:The use of Phosphate binders instead of the widely used silica binder resulted in improved temperature resistance, increased tensile strength and decreased coefficient of thermal expansion. The effects were largest for the Phosphate binder which contained the largest amount of phosphoric Acid (P/Al atom ratio = 24 in the liquid binder). These effects were probably due to the protection of the SiC whiskers by the binder phases (aluminium metaPhosphate or aluminium orthoPhosphate), the binder-SiC reaction product (SiP_2O_7) and the binder-aluminium reaction product (AIP) from further reaction between the SiC and aluminium. The tensile strength of the composite containing the SiC whisker preform made with the Phosphate binder (P/Al atom ratio = 6 or 24 in the liquid binder) was increased after heating at up to 600 °C for 240 h. The silicon Phosphate (SiP_2O_7) acted as an in situ binder and was primarily responsible for increasing the compressive strength of the preform and increasing the temperature resistance of the composite. The carbon fibre composite containing the preform made by using the Phosphate binder (P/Al atom ratio = 24 in the liquid binder) with either water or acetone as the liquid carrier during wet forming of the preform had a higher tensile strength than the carbon fibre composite made by using the silica binder. After composite heat exposure to 600 °C for 14 h, the carbon fibre composite made by using this Phosphate binder with acetone as the liquid carrier during wet forming of the preform showed the best temperature resistance, while the carbon fibre composites made by using this Phosphate binder with water as the carrier showed the second best temperature resistance, and that made by using silica binder was the worst. The reason for the better effect of the Phosphate binder than the silica binder is probably due to the ability of the Phosphate binder and the binder-aluminium reaction product (AIP) to protect the carbon fibres from the undesirable reaction between the carbon fibres and aluminium. The lack of a binder-fibre reaction contributed to making the carbon fibre composites less temperature resistant than the SiC whisker composites. The use of a higher binder concentration is attractive for increasing the temperature resistance of the composites. The binder concentration in the preform can be increased by increasing the binder concentration in the slurry used in the wet forming of the preform.
Laurent Nussaume - One of the best experts on this subject based on the ideXlab platform.
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interplay between jasmonic Acid Phosphate signaling and the regulation of glycerolipid homeostasis in arabidopsis
Plant and Cell Physiology, 2019Co-Authors: Florian Chevalier, Laura Cuyas, Vali Rie Gros, Khawla Seddiki, David Secco, James Whelan, Serge Chiarenza, Maryse A Block, Juliette Jouhet, Laurent NussaumeAbstract:: Jasmonic Acid (JA) biosynthesis and signaling are activated in Arabidopsis cultivated in Phosphate (Pi) deprived conditions. This activation occurs mainly in photosynthetic tissues and is less important in roots. In leaves, the enhanced biosynthesis of JA coincides with membrane glycerolipid remodeling triggered by the lack of Pi. We addressed the possible role of JA on the dynamics and magnitude of glycerolipid remodeling in response to Pi deprivation and resupply. Based on combined analyses of gene expression, JA biosynthesis and glycerolipid remodeling in wild-type Arabidopsis and in the coi1-16 mutant, JA signaling seems important in the determination of the basal levels of phosphatidylcholine, phosphatidic Acid (PA), monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol. JA impact on MGDG steady state level and fluctuations seem contradictory. In the coi1-16 mutant, the steady state level of MGDG is higher, possibly due to a higher level of PA in the mutant, activating MGD1, and to an increased expression of MGD3. These results support a possible impact of JA in limiting the overall content of this lipid. Concerning lipid variations, upon Pi deprivation, JA seems rather associated with a specific MGDG increase. Following Pi resupply, whereas the expression of glycerolipid remodeling genes returns to basal level, JA biosynthesis and signaling genes are still upregulated, likely due to a JA-induced positive feedback remaining active. Distinct impacts on enzymes synthesizing MGDG, that is, downregulating MGD3, possibly activating MGD1 expression and limiting the activation of MGD1 via PA, might allow JA playing a role in a sophisticated fine tuning of galactolipid variations.
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Interplay between Jasmonic Acid, Phosphate Signaling and the Regulation of Glycerolipid Homeostasis in Arabidopsis
Plant and Cell Physiology, 2019Co-Authors: Florian Chevalier, Laura Cuyas, Khawla Seddiki, David Secco, James Whelan, Serge Chiarenza, Juliette Jouhet, Valérie Gros, Maryse Block, Laurent NussaumeAbstract:Jasmonic Acid (JA) biosynthesis and signaling are activated in Arabidopsis cultivated in Phosphate (Pi) deprived conditions. This activation occurs mainly in photosynthetic tissues and is less important in roots. In leaves, the enhanced biosynthesis of JA coincides with membrane glycerolipid remodeling triggered by the lack of Pi. We addressed the possible role of JA on the dynamics and magnitude of glycerolipid remodeling in response to Pi-deprivation and resupply. Based on combined analyses of gene expression, JA biosynthesis and glycerolipid remodeling in wild type Arabidopsis and in the coi1-16 mutant, JA signaling seems important in the determination of the basal levels of phosphatidylcholine (PC), phosphatidic Acid (PA), monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG). JA impact on MGDG steady state level and fluctuations seem contradictory. In the coi1-16 mutant, the steady state level of MGDG is higher, possibly due to a higher level of PA in the mutant, activating MGD1, and to an increased expression of MGD3. These results support a possible impact of JA in limiting the overall content of this lipid. Concerning lipid variations, upon Pi-deprivation, JA seems rather associated with a specific MGDG increase. Following Pi-resupply, whereas the expression of glycerolipid remodeling genes returns to basal level, JA biosynthesis and signaling genes are still upregulated, likely due to a JA-induced positive feedback remaining active. Distinct impacts on enzymes synthesizing MGDG, i.e. downregulating MGD3, possibly activating MGD1 expression and limiting the activation of MGD1 via PA, might allow JA playing a role in a sophisticated fine tuning of galactolipid variations.
P A Distin - One of the best experts on this subject based on the ideXlab platform.
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gallium solvent extraction from Acidic solutions with octyl phenyl Acid Phosphate opap reagents
Hydrometallurgy, 1995Co-Authors: I Mihaylov, P A DistinAbstract:Abstract Solvent extraction of gallium from Acidic solutions using octyl phenyl Acid Phosphate (OPAP) with several different ratios of its components, mono- and di-octyl phenyl phosphoric Acids (HM and HD, respectively), has been studied. The extraction is described by four simultaneous reactions, leading to the formation of four metal-extractant complexes: GaM 3 , GaD 3 , GaM 2 D and GaMD 2 . The proposed reactions explain and allow prediction of distribution coefficients as a function of pH, extractant concentration and composition.
Florian Chevalier - One of the best experts on this subject based on the ideXlab platform.
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interplay between jasmonic Acid Phosphate signaling and the regulation of glycerolipid homeostasis in arabidopsis
Plant and Cell Physiology, 2019Co-Authors: Florian Chevalier, Laura Cuyas, Vali Rie Gros, Khawla Seddiki, David Secco, James Whelan, Serge Chiarenza, Maryse A Block, Juliette Jouhet, Laurent NussaumeAbstract:: Jasmonic Acid (JA) biosynthesis and signaling are activated in Arabidopsis cultivated in Phosphate (Pi) deprived conditions. This activation occurs mainly in photosynthetic tissues and is less important in roots. In leaves, the enhanced biosynthesis of JA coincides with membrane glycerolipid remodeling triggered by the lack of Pi. We addressed the possible role of JA on the dynamics and magnitude of glycerolipid remodeling in response to Pi deprivation and resupply. Based on combined analyses of gene expression, JA biosynthesis and glycerolipid remodeling in wild-type Arabidopsis and in the coi1-16 mutant, JA signaling seems important in the determination of the basal levels of phosphatidylcholine, phosphatidic Acid (PA), monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol. JA impact on MGDG steady state level and fluctuations seem contradictory. In the coi1-16 mutant, the steady state level of MGDG is higher, possibly due to a higher level of PA in the mutant, activating MGD1, and to an increased expression of MGD3. These results support a possible impact of JA in limiting the overall content of this lipid. Concerning lipid variations, upon Pi deprivation, JA seems rather associated with a specific MGDG increase. Following Pi resupply, whereas the expression of glycerolipid remodeling genes returns to basal level, JA biosynthesis and signaling genes are still upregulated, likely due to a JA-induced positive feedback remaining active. Distinct impacts on enzymes synthesizing MGDG, that is, downregulating MGD3, possibly activating MGD1 expression and limiting the activation of MGD1 via PA, might allow JA playing a role in a sophisticated fine tuning of galactolipid variations.
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Interplay between Jasmonic Acid, Phosphate Signaling and the Regulation of Glycerolipid Homeostasis in Arabidopsis
Plant and Cell Physiology, 2019Co-Authors: Florian Chevalier, Laura Cuyas, Khawla Seddiki, David Secco, James Whelan, Serge Chiarenza, Juliette Jouhet, Valérie Gros, Maryse Block, Laurent NussaumeAbstract:Jasmonic Acid (JA) biosynthesis and signaling are activated in Arabidopsis cultivated in Phosphate (Pi) deprived conditions. This activation occurs mainly in photosynthetic tissues and is less important in roots. In leaves, the enhanced biosynthesis of JA coincides with membrane glycerolipid remodeling triggered by the lack of Pi. We addressed the possible role of JA on the dynamics and magnitude of glycerolipid remodeling in response to Pi-deprivation and resupply. Based on combined analyses of gene expression, JA biosynthesis and glycerolipid remodeling in wild type Arabidopsis and in the coi1-16 mutant, JA signaling seems important in the determination of the basal levels of phosphatidylcholine (PC), phosphatidic Acid (PA), monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG). JA impact on MGDG steady state level and fluctuations seem contradictory. In the coi1-16 mutant, the steady state level of MGDG is higher, possibly due to a higher level of PA in the mutant, activating MGD1, and to an increased expression of MGD3. These results support a possible impact of JA in limiting the overall content of this lipid. Concerning lipid variations, upon Pi-deprivation, JA seems rather associated with a specific MGDG increase. Following Pi-resupply, whereas the expression of glycerolipid remodeling genes returns to basal level, JA biosynthesis and signaling genes are still upregulated, likely due to a JA-induced positive feedback remaining active. Distinct impacts on enzymes synthesizing MGDG, i.e. downregulating MGD3, possibly activating MGD1 expression and limiting the activation of MGD1 via PA, might allow JA playing a role in a sophisticated fine tuning of galactolipid variations.
L.a. Damani - One of the best experts on this subject based on the ideXlab platform.
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Triazolines. XXI: Preformulation Degradation Kinetics and Chemical Stability of a Novel Triazoline Anticonvulsant
Journal of Pharmaceutical Sciences, 1992Co-Authors: M.a. Freeke Hamelijnck, Paul J. Stevenson, Pankaja K. Kadaba, L.a. DamaniAbstract:Abstract The effect of pH, temperature, and two buffer species (citric Acid‐Phosphate and bicarbonate‐carbonate) on the stability of 1‐(4‐chlorophenyl)‐5‐(4‐pyridyl)‐Δ 2 ‐1,2,3‐triazoline (ADD17014; 1), a novel triazoline anticonvulsant, was determined by HPLC. One of the main degradation products of 1 at pH 7.0 was isolated by TLC and identified as the aziridine derivative by MS. Investigations were carried out over a range of pH (2.2–10.7) and buffer concentration [ionic strength ( μ ), 0.25–4.18] at 23°C. The degradation followed buffer‐catalyzed, pseudo‐first‐order kinetics and was accelerated by a decrease in pH and an increase in temperature. The activation energy for the degradation in citric Acid‐Phosphate buffer (pH 7.0 and constant ionic strength μ at 0.54) was 12.5 kcal/mol. General Acid catalysis was observed at pH 7.0 in citric Acid‐Phosphate buffer. The salt effect on the degradation obeyed the modified Debye‐Huckel equation well; however, the observed charge product ( Z A Z B ) value (2.69) deviated highly from the theoretical value (1.0), perhaps because of the high μ values (0.25–4.18) of the solutions used. The stability data will be useful in preformulation studies in the development of a stable, oral dosage form of 1.
