The Experts below are selected from a list of 75 Experts worldwide ranked by ideXlab platform
David Julian Mcclements - One of the best experts on this subject based on the ideXlab platform.
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role of Calcium and Calcium binding Agents on the lipase digestibility of emulsified lipids using an in vitro digestion model
Food Hydrocolloids, 2010Co-Authors: Eric A Decker, David Julian McclementsAbstract:Controlling the digestibility of lipids within the gastrointestinal tract is important for developing food and pharmaceutical products. In vitro digestion methods are commonly used to study the influence of formulation composition and microstructure on lipid digestibility. In this paper, we focus on the impact of Calcium and Calcium-binding Agents on the rate of lipid droplet digestion in corn oil-in-water emulsions monitored using a pH-stat method. The rate of fatty acid production increased with increasing Calcium, e.g., the free fatty acids released after 20 min digestion was 95% for 20 mM CaCl2. The ability of Calcium to increase the digestion rate was found for three different emulsifiers used to stabilize the initial lipid droplets: lyso-lecithin, caseinate and β-lactoglobulin. For these three systems, the initial rate of lipid digestion increased in the following order lyso-lecithin > β-lactoglobulin > caseinate at both 0 and 20 mM CaCl2, but the rate was considerably faster at higher Calcium levels for all systems. The addition of EDTA, a Calcium Chelating Agent, to emulsions containing 20 mM CaCl2 caused an appreciable decrease in lipid digestion rate, reducing the amount of free fatty acids produced after 20 min from around 97% to 32% when the EDTA level was increased from 0 to 5 mM. Finally, we examined the impact of two anionic polysaccharides (pectin and alginate) on the rate of lipid digestion in emulsions containing 20 mM CaCl2. High methoxy pectin, which does not bind Calcium strongly, did not have a major effect on the rate of digestion, whereas alginate, which does bind Calcium strongly, depressed the rate considerably. This study has important implications for designing and testing delivery systems that control lipid digestion.
Toshiyuki Hashida - One of the best experts on this subject based on the ideXlab platform.
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novel selective dyeing method for chrysotile asbestos detection in concrete materials
Environmental Science & Technology, 2008Co-Authors: Yoshihiko Oke, Nakamichi Yamasaki, Go Yamamoto, Kazuhiro Sasaki, Naomi Maeta, Hirokazu Fujimaki, Toshiyuki HashidaAbstract:There are a tremendous number of asbestos-containing buildings without any surveys on the presence of asbestos because of the difficulty to detect asbestos in building materials simply and quickly, although a great deal of worldwide effort was put into removing asbestos of which inhalation causes serious diseases. In this study, we newly developed a simple dyeing method to detect chrysotile asbestos, the most commonly used type of asbestos, in asbestos-cement composite materials using magnesium-Chelating organic dyes. As an essential process for selective dyeing of chrysotile asbestos, special pretreatment with a Calcium-Chelating Agent was developed to prevent the dyes from reacting with Calcium, which is the major component of concrete materials. Our developed selective dyeing method was shown to possess sufficient sensitivity for detecting chrysotile asbestos in an amount greater than 0.1 mass% in concrete specimens, and there was an approximately linear relationship between the area fraction of dyed spots and the mass fraction of chrysotile asbestos. Our results may provide a basis for further development of a simple on-site detection method for chrysotile asbestos in building materials and may facilitate the progress of control and removal of asbestos in the environment.
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novel selective dyeing method for chrysotile asbestos detection in concrete materials
Environmental Science & Technology, 2008Co-Authors: Nakamichi Yamasaki, Go Yamamoto, Kazuhiro Sasaki, Naomi Maeta, Hirokazu Fujimaki, Toshiyuki HashidaAbstract:There are a tremendous number of asbestos-containing buildings without any surveys on the presence of asbestos because of the difficulty to detect asbestos in building materials simply and quickly, although a great deal of worldwide effort was put into removing asbestos of which inhalation causes serious diseases. In this study, we newly developed a simple dyeing method to detect chrysotile asbestos, the most commonly used type of asbestos, in asbestos−cement composite materials using magnesium-Chelating organic dyes. As an essential process for selective dyeing of chrysotile asbestos, special pretreatment with a Calcium-Chelating Agent was developed to prevent the dyes from reacting with Calcium, which is the major component of concrete materials. Our developed selective dyeing method was shown to possess sufficient sensitivity for detecting chrysotile asbestos in an amount greater than 0.1 mass% in concrete specimens, and there was an approximately linear relationship between the area fraction of dyed s...
Eric A Decker - One of the best experts on this subject based on the ideXlab platform.
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role of Calcium and Calcium binding Agents on the lipase digestibility of emulsified lipids using an in vitro digestion model
Food Hydrocolloids, 2010Co-Authors: Eric A Decker, David Julian McclementsAbstract:Controlling the digestibility of lipids within the gastrointestinal tract is important for developing food and pharmaceutical products. In vitro digestion methods are commonly used to study the influence of formulation composition and microstructure on lipid digestibility. In this paper, we focus on the impact of Calcium and Calcium-binding Agents on the rate of lipid droplet digestion in corn oil-in-water emulsions monitored using a pH-stat method. The rate of fatty acid production increased with increasing Calcium, e.g., the free fatty acids released after 20 min digestion was 95% for 20 mM CaCl2. The ability of Calcium to increase the digestion rate was found for three different emulsifiers used to stabilize the initial lipid droplets: lyso-lecithin, caseinate and β-lactoglobulin. For these three systems, the initial rate of lipid digestion increased in the following order lyso-lecithin > β-lactoglobulin > caseinate at both 0 and 20 mM CaCl2, but the rate was considerably faster at higher Calcium levels for all systems. The addition of EDTA, a Calcium Chelating Agent, to emulsions containing 20 mM CaCl2 caused an appreciable decrease in lipid digestion rate, reducing the amount of free fatty acids produced after 20 min from around 97% to 32% when the EDTA level was increased from 0 to 5 mM. Finally, we examined the impact of two anionic polysaccharides (pectin and alginate) on the rate of lipid digestion in emulsions containing 20 mM CaCl2. High methoxy pectin, which does not bind Calcium strongly, did not have a major effect on the rate of digestion, whereas alginate, which does bind Calcium strongly, depressed the rate considerably. This study has important implications for designing and testing delivery systems that control lipid digestion.
Thibaud Coradin - One of the best experts on this subject based on the ideXlab platform.
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organically modified porous hydroxyapatites a comparison between alkylphosphonate grafting and citrate chelation
Journal of Solid State Chemistry, 2008Co-Authors: L Elhammari, H Marroun, Abdelaziz Laghzizil, A Saoiabi, Cecile Roux, Jacques Livage, Thibaud CoradinAbstract:Two alternative methods to prepare organically modified porous hydroxyapatites following a 'one pot' approach were compared. The partial substitution of inorganic phosphates by alkylphosphonates leads to mesoporous materials with high specific surface area (>200 m{sup 2} g{sup -1}). The incorporation of the organic moieties within the hydroxyapatite structure is confirmed by Infra-red and solid-state NMR spectroscopy and depends on the nature of the alkyl chain. However, it induces a significant loss of the material crystallinity. In contrast, the introduction of citrate, a Calcium-Chelating Agent, to the precursor solution does not improve the material specific surface area but allows a better control of the hydroxyapatite structure, both in terms of crystallinity and pore size distribution. - Graphical abstract: Evolution of pore size distribution of hydroxyapatite (HAp) after alkylphosphonate grafting (20% TPOH) or citrate addition (c-HAp) demonstrates the formation of organically modified mesoporous materials.
Jan Rydstrom - One of the best experts on this subject based on the ideXlab platform.
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purification of recombinant membrane proteins tagged with calmodulin binding domains by affinity chromatography on calmodulin agarose example of nicotinamide nucleotide transhydrogenase
Nature Protocols, 2007Co-Authors: Nikolay B. Pestov, Jan RydstromAbstract:This protocol describes affinity purification of bacterially expressed, recombinant membrane proteins fused with calmodulin-binding domains. As exemplified by the Escherichia coli nicotinamide nucleotide transhydrogenase, this method allows isolation of the protein fusions in a single chromatography step using elution with the Calcium Chelating Agent EDTA and, unlike purification of His-tagged proteins on nickel chelate, it is not sensitive to the presence of strong reducing Agents (e.g., DTT). Our protocol involves disruption of host bacteria by sonication, sedimentation of membranes by differential centrifugation, solubilization of membrane proteins and affinity chromatography on calmodulin-agarose. To achieve maximum purity and yield, the use of a combination of non-ionic and anionic detergents is suggested. Purification takes two working days, with an overnight wash of the column to increase the purity of the product.