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Anura V. Kurpad - One of the best experts on this subject based on the ideXlab platform.
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the relationship of endogenous plasma concentrations of β hydroxy β Methyl Butyrate hmb to age and total appendicular lean mass in humans
Experimental Gerontology, 2016Co-Authors: Rebecca Kuriyan, Deepa P. Lokesh, Sumithra Selvam, J. Jayakumar, Mamatha G. Philip, Sathyavageeswaran Shreeram, Anura V. KurpadAbstract:The maintenance of muscle mass and muscle strength is important for reducing the risk of chronic diseases. The age- related loss of muscle mass and strength is associated with adverse outcomes of physical disability, frailty and death. β-Hydroxy β-Methyl Butyrate (HMB), a metabolite of leucine, has beneficial effects on muscle mass and strength under various catabolic conditions. The objectives of the present study were to determine if age- related differences existed in endogenous plasma HMB levels, and to assess if HMB levels correlated to total appendicular lean mass and forearm grip strength. Anthropometry, dietary and physical activity assessment, and the estimation of fasting plasma HMB concentrations and handgrip strength were performed on the 305 subjects (children, young adults and older adults). Lean mass, which serves as a surrogate for muscle mass was measured using dual energy X-ray absorptiometry (DEXA). Mean plasma HMB concentrations were significantly lower with increasing age groups, with children having highest mean HMB concentration (p<0.01) followed by young adults and older adults. Female subjects (across all ages) had significantly lower plasma HMB concentrations. A significant positive correlation between HMB concentrations and appendicular lean mass normalized for body weight (%), appendicular lean mass (r=0.37; p<0.001) was observed in the young adults and older adults group. Handgrip strength was positively associated with plasma HMB concentrations in young adults (r=0.58; p<0.01) and the older adults group (r=0.28; p<0.01). The findings of the present study suggest that there is an age- related decline in endogenous HMB concentrations in humans and the HMB concentrations were positively correlated with appendicular lean mass and hand grip strength in young adults and older adults group.
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The relationship of endogenous plasma concentrations of β-Hydroxy β-Methyl Butyrate (HMB) to age and total appendicular lean mass in humans.
Experimental gerontology, 2016Co-Authors: Rebecca Kuriyan, Deepa P. Lokesh, Sumithra Selvam, J. Jayakumar, Mamatha G. Philip, Sathyavageeswaran Shreeram, Anura V. KurpadAbstract:The maintenance of muscle mass and muscle strength is important for reducing the risk of chronic diseases. The age- related loss of muscle mass and strength is associated with adverse outcomes of physical disability, frailty and death. β-Hydroxy β-Methyl Butyrate (HMB), a metabolite of leucine, has beneficial effects on muscle mass and strength under various catabolic conditions. The objectives of the present study were to determine if age- related differences existed in endogenous plasma HMB levels, and to assess if HMB levels correlated to total appendicular lean mass and forearm grip strength. Anthropometry, dietary and physical activity assessment, and the estimation of fasting plasma HMB concentrations and handgrip strength were performed on the 305 subjects (children, young adults and older adults). Lean mass, which serves as a surrogate for muscle mass was measured using dual energy X-ray absorptiometry (DEXA). Mean plasma HMB concentrations were significantly lower with increasing age groups, with children having highest mean HMB concentration (p
Miguel Postigo - One of the best experts on this subject based on the ideXlab platform.
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Vapor−Liquid Equilibrium Data for the Binary Methyl Esters (Butyrate, Pentanoate, and Hexanoate) (1) + Acetonitrile (2) Systems at 93.32 kPa
Journal of Chemical & Engineering Data, 2006Co-Authors: Alberto Camacho, Juan M. Moll, And Salvador Canzonieri, Miguel PostigoAbstract:Isobaric vapor−liquid equilibria were measured for the three binary systems of Methyl Butyrate, Methyl pentanoate, and Methyl hexanoate with propannenitrile at a constant pressure of 93.32 kPa. The measurements were carried out with in small recirculating still. The composition of condensed vapor and liquid phases was calculated indirectly from density measurements made with a vibrating tube densimeter. The thermodynamic consistency of the data was verified with two point-to-point tests. Activity coefficients calculated from experimental data have been correlated by several models and compared with predictions of group-contribution models. These systems exhibit positive deviations from ideality. The Methyl Butyrate + propannenitrile system formed a minimum boiling azeotrope.
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vapor liquid equilibrium data for the binary Methyl esters Butyrate pentanoate and hexanoate 1 acetonitrile 2 systems at 93 32 kpa
Journal of Chemical & Engineering Data, 2006Co-Authors: Alberto Camacho, Juan M. Moll, And Salvador Canzonieri, Miguel PostigoAbstract:Isobaric vapor−liquid equilibria were measured for the three binary systems of Methyl Butyrate, Methyl pentanoate, and Methyl hexanoate with propannenitrile at a constant pressure of 93.32 kPa. The measurements were carried out with in small recirculating still. The composition of condensed vapor and liquid phases was calculated indirectly from density measurements made with a vibrating tube densimeter. The thermodynamic consistency of the data was verified with two point-to-point tests. Activity coefficients calculated from experimental data have been correlated by several models and compared with predictions of group-contribution models. These systems exhibit positive deviations from ideality. The Methyl Butyrate + propannenitrile system formed a minimum boiling azeotrope.
Rebecca Kuriyan - One of the best experts on this subject based on the ideXlab platform.
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the relationship of endogenous plasma concentrations of β hydroxy β Methyl Butyrate hmb to age and total appendicular lean mass in humans
Experimental Gerontology, 2016Co-Authors: Rebecca Kuriyan, Deepa P. Lokesh, Sumithra Selvam, J. Jayakumar, Mamatha G. Philip, Sathyavageeswaran Shreeram, Anura V. KurpadAbstract:The maintenance of muscle mass and muscle strength is important for reducing the risk of chronic diseases. The age- related loss of muscle mass and strength is associated with adverse outcomes of physical disability, frailty and death. β-Hydroxy β-Methyl Butyrate (HMB), a metabolite of leucine, has beneficial effects on muscle mass and strength under various catabolic conditions. The objectives of the present study were to determine if age- related differences existed in endogenous plasma HMB levels, and to assess if HMB levels correlated to total appendicular lean mass and forearm grip strength. Anthropometry, dietary and physical activity assessment, and the estimation of fasting plasma HMB concentrations and handgrip strength were performed on the 305 subjects (children, young adults and older adults). Lean mass, which serves as a surrogate for muscle mass was measured using dual energy X-ray absorptiometry (DEXA). Mean plasma HMB concentrations were significantly lower with increasing age groups, with children having highest mean HMB concentration (p<0.01) followed by young adults and older adults. Female subjects (across all ages) had significantly lower plasma HMB concentrations. A significant positive correlation between HMB concentrations and appendicular lean mass normalized for body weight (%), appendicular lean mass (r=0.37; p<0.001) was observed in the young adults and older adults group. Handgrip strength was positively associated with plasma HMB concentrations in young adults (r=0.58; p<0.01) and the older adults group (r=0.28; p<0.01). The findings of the present study suggest that there is an age- related decline in endogenous HMB concentrations in humans and the HMB concentrations were positively correlated with appendicular lean mass and hand grip strength in young adults and older adults group.
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The relationship of endogenous plasma concentrations of β-Hydroxy β-Methyl Butyrate (HMB) to age and total appendicular lean mass in humans.
Experimental gerontology, 2016Co-Authors: Rebecca Kuriyan, Deepa P. Lokesh, Sumithra Selvam, J. Jayakumar, Mamatha G. Philip, Sathyavageeswaran Shreeram, Anura V. KurpadAbstract:The maintenance of muscle mass and muscle strength is important for reducing the risk of chronic diseases. The age- related loss of muscle mass and strength is associated with adverse outcomes of physical disability, frailty and death. β-Hydroxy β-Methyl Butyrate (HMB), a metabolite of leucine, has beneficial effects on muscle mass and strength under various catabolic conditions. The objectives of the present study were to determine if age- related differences existed in endogenous plasma HMB levels, and to assess if HMB levels correlated to total appendicular lean mass and forearm grip strength. Anthropometry, dietary and physical activity assessment, and the estimation of fasting plasma HMB concentrations and handgrip strength were performed on the 305 subjects (children, young adults and older adults). Lean mass, which serves as a surrogate for muscle mass was measured using dual energy X-ray absorptiometry (DEXA). Mean plasma HMB concentrations were significantly lower with increasing age groups, with children having highest mean HMB concentration (p
Yujun Zhu - One of the best experts on this subject based on the ideXlab platform.
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Transesterification of Tributyrin and Dehydration of Fructose over a Carbon-Based Solid Acid Prepared by Carbonization and Sulfonation of Glucose.
ChemPlusChem, 2015Co-Authors: Chuanxu Wang, Fulong Yuan, Lijing Liu, Xiaoyu Niu, Yujun ZhuAbstract:A series of carbon-based sulfonated solid acid (CS) catalysts can be prepared through a facile method of direct simultaneous carbonization and sulfonation of d-glucose with concentrated sulfuric acid without a hydrothermal process. Temperature is a key factor in obtaining CS catalysts with higher amounts of -SO3 H acid sites. The transesterification of tributyrin with methanol and the dehydration of fructose to 5-hydroxymenthylfurfural (5-HMF) are investigated over the CS catalysts. The CS-150 catalyst, which is the CS catalyst prepared at 150 °C, shows much higher catalytic activity to give a tributyrin conversion of 99.4 %. The yield of Methyl Butyrate is 97.2 % and a remarkably high yield of 5-HMF (93 %) can be obtained efficiently; these yields result from the high acid density of -SO3 H. Good linearity is displayed between the total acid density and yield of Methyl Butyrate/5-HMF. The CS-150 catalyst has high stability and good recyclability for the dehydration of fructose.
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Preparation of KF–La2O2CO3 solid base catalysts and their excellent catalytic activities for transesterification of tributyrin with methanol
Catalysis Science & Technology, 2014Co-Authors: Wen Jiang, Fulong Yuan, Xiaoyu Niu, Yujun ZhuAbstract:A series of 25% KF–La2O2CO3 catalysts (25-KF–LOC-x, x = 673, 723 and 773) were prepared at different calcination temperatures, which were tested as basic catalysts for the transesterification of tributyrin with methanol to produce Methyl Butyrate and characterized by means of XRD, SEM, CO2-TPD, FTIR, XPS and XRF. It was found that the calcination temperature greatly influences the catalytic activity, and its order is 25-KF–LOC-673 < 25-KF–LOC-723 < 25-KF–LOC-773. Especially, the 25-KF–LOC-773 catalyst exhibits a very high activity, and the conversion of tributyrin is nearly 100%, the yield of Methyl Butyrate reaches 94% at 308 K. The activation energy of the 25-KF–LOC-773 catalyst is as low as 55.03 kJ mol−1. The excellent catalytic activity of the 25-KF–LOC-773 catalyst can be attributed to the largest amount of surface hydroxyl among these 25-KF–LOC-x catalysts. The results indicate that the Bronsted base is the main active site at low reaction temperature. The recycling use and stability have been investigated over the 25-KF–LOC-773 catalyst. The results indicate that the 25-KF–LOC-773 catalyst has a high stability after being stored for 90 days. The deactivation of the used 25-KF–LOC-773 catalyst at 308 K is due to the loss of hydroxyl on the surface. However, the conversion of tributyrin can reach 91%, and the yield of Methyl Butyrate also can achieve 64% when the transesterification reaction is performed at 338 K over the second used 25-KF–LOC-773 catalyst. It indicates that the second used 25-KF–LOC-773 catalyst still possesses good catalytic activity at the higher reaction temperature due to the unchanged strong Lewis basic sites provided with surface oxygen anions.
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Activity and stability of solid base KF/La2O3 catalysts for transesterification of tributyrin with methanol
Reaction Kinetics Mechanisms and Catalysis, 2013Co-Authors: Xiaoyu Niu, Fulong Yuan, Chunmei Xing, Wen Jiang, Yongli Dong, Yujun ZhuAbstract:A series of solid base catalysts of 5–20 % KF/La2O3 were prepared via an impregnation method and used in the transesterification of methanol with tributyrin to produce Methyl Butyrate. Under the suitable reaction conditions (catalyst amount of 30 mg; reaction temperature of 338 K; reaction time of 1.5 h; the molar ratio of methanol to tributyrin of 30), the tributyrin conversion of 99.9 % and the Methyl Butyrate selectivity of 98.1 % are obtained over 15 % KF/La2O3 catalyst. Furthermore, the recycling experiment was adopted to investigate the stability of the catalyst, and the surface active site of KF/La2O3 catalyst was also discussed. The X-ray diffraction, CO2-TPD and X-ray fluorescence characterization results indicated that LaOF were generated by the interaction of KF with La2O3, which was good for the transesterification of methanol with tributyrin, and the LaOF may be an effective component to reduce the loss of active site, retaining a certain stability of catalyst.
Alberto Camacho - One of the best experts on this subject based on the ideXlab platform.
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Vapor−Liquid Equilibrium Data for the Binary Methyl Esters (Butyrate, Pentanoate, and Hexanoate) (1) + Acetonitrile (2) Systems at 93.32 kPa
Journal of Chemical & Engineering Data, 2006Co-Authors: Alberto Camacho, Juan M. Moll, And Salvador Canzonieri, Miguel PostigoAbstract:Isobaric vapor−liquid equilibria were measured for the three binary systems of Methyl Butyrate, Methyl pentanoate, and Methyl hexanoate with propannenitrile at a constant pressure of 93.32 kPa. The measurements were carried out with in small recirculating still. The composition of condensed vapor and liquid phases was calculated indirectly from density measurements made with a vibrating tube densimeter. The thermodynamic consistency of the data was verified with two point-to-point tests. Activity coefficients calculated from experimental data have been correlated by several models and compared with predictions of group-contribution models. These systems exhibit positive deviations from ideality. The Methyl Butyrate + propannenitrile system formed a minimum boiling azeotrope.
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vapor liquid equilibrium data for the binary Methyl esters Butyrate pentanoate and hexanoate 1 acetonitrile 2 systems at 93 32 kpa
Journal of Chemical & Engineering Data, 2006Co-Authors: Alberto Camacho, Juan M. Moll, And Salvador Canzonieri, Miguel PostigoAbstract:Isobaric vapor−liquid equilibria were measured for the three binary systems of Methyl Butyrate, Methyl pentanoate, and Methyl hexanoate with propannenitrile at a constant pressure of 93.32 kPa. The measurements were carried out with in small recirculating still. The composition of condensed vapor and liquid phases was calculated indirectly from density measurements made with a vibrating tube densimeter. The thermodynamic consistency of the data was verified with two point-to-point tests. Activity coefficients calculated from experimental data have been correlated by several models and compared with predictions of group-contribution models. These systems exhibit positive deviations from ideality. The Methyl Butyrate + propannenitrile system formed a minimum boiling azeotrope.