Background:Children and adolescents can be distinguished by different typologies(clusters) of physical activity and sedentary behavior.How physical activity and sedentary behaviors change over time within different ty...Background:Children and adolescents can be distinguished by different typologies(clusters) of physical activity and sedentary behavior.How physical activity and sedentary behaviors change over time within different typologies is not known.This study examined longitudinal changes in physical activity and sedentary time among children and adolescents with different baseline typologies of activity-related behavior.Methods:In this longitudinal study(3 annual time points) of children(n=600,age=9.2±0.4 years(mean±SD),50.3% girls) and adolescents(n=1037,age=13.6±1.7 years,48.4% girls),participants were recruited in Spain in 2011-2012.Latent class analyses identified typologies based on self-reported screen,educational,social and relaxing sedentary behaviors,active travel,muscle strengthening activity,and sport at baseline.Within each typology,linear mixed growth models explored longitudinal changes in accelerometer-derived moderate-to-vigorous physical activity and sedentary time,as well as time by class interactions.Results:Three typologies were identified among children( "social screenies",12.8%;"exercisers",61.5%;and "non-sporty active commuters",25.7%) and among adolescents "active screenies",43.5%;"active academics",35.0%;and "non-sporty active commuters",21.5%) at baseline.Sedentary time increased within each typology among children and adolescents,with no significant differences between typologies.No changes in physical activity were found in any typology among children.In adolescents,physical activity declined within all typologies,with "non-sporty active commuters" declining significantly more than "active screenies" over 3 years.Conclusion:These results support the need for interveation to promote physical activity and prevent increases in sedentary time during childhood and adolescence.Adolescents characterized as "non-sporty active commuters" may require specific interventions to maintain their physical activity over time.展开更多
The canola oil industry generates significant waste as canola meal(CM)which has limited scope and applications.This study demonstrates the possibility of valorization of CM as a sustainable natural filler in a biodegr...The canola oil industry generates significant waste as canola meal(CM)which has limited scope and applications.This study demonstrates the possibility of valorization of CM as a sustainable natural filler in a biodegradable polymer composite of Poly(lactic acid)(PLA).Generally,interfacial bonding between natural fibers and the polymer matrix in the composite is weak and non-uniform.One possible solution is to derivatize natural fibre to introduce interfacial bond strength and compatibility with the PLA polymer matrix.Here,CM was succinylated in a reactive extrusion process using succinic anhydride at 30 wt%to get 14%derivatization with 0.02 g of-COOH density per g of CM.The CM or succinylated CM at 5 and 15 wt%was co-extruded with amorphous PLA to get composite fibers.CM-PLA and succinylated CM-PLA biocomposites were foamed using a mild and green microcellular foaming process,with CO_(2) as an impregnating agent without any addition of organic solvents.The properties of the foams were analyzed using differential scanning calorimetry(DSC),Dynamic mechanical thermal analysis(DMTA),shrinkage,and imaging.The addition of CM or succinylated CM as a natural filler did not significantly change the glass transition temperature,melting point,percent crystallization,stiffness,and thermal stability of PLA foams.This suggests succinylation(modification)of CM is not a mandatory step for improving interphase compatibility with the amorphous PLA.The new PLA-CM foams can be a good alternative in the packaging industry replacing the existing petroleum-based polymer foams.展开更多
基金supported by the National Plan for Research, Development and Innovation (RDi) Ministry of Science and Innovation (DEP 2010-21662-C04-00)awarded a "Juan de la Cierva" postdoctoral fellowship (FJCI-2015-25867) from the Spanish Ministry of Economy,Industry,and Competitiveness+1 种基金supported by the Spanish Ministry of Economy and Competitiveness (RTI2018-095284-J-100)the Spanish Ministry of Science and Innovation (RYC2019-027287-I)
文摘Background:Children and adolescents can be distinguished by different typologies(clusters) of physical activity and sedentary behavior.How physical activity and sedentary behaviors change over time within different typologies is not known.This study examined longitudinal changes in physical activity and sedentary time among children and adolescents with different baseline typologies of activity-related behavior.Methods:In this longitudinal study(3 annual time points) of children(n=600,age=9.2±0.4 years(mean±SD),50.3% girls) and adolescents(n=1037,age=13.6±1.7 years,48.4% girls),participants were recruited in Spain in 2011-2012.Latent class analyses identified typologies based on self-reported screen,educational,social and relaxing sedentary behaviors,active travel,muscle strengthening activity,and sport at baseline.Within each typology,linear mixed growth models explored longitudinal changes in accelerometer-derived moderate-to-vigorous physical activity and sedentary time,as well as time by class interactions.Results:Three typologies were identified among children( "social screenies",12.8%;"exercisers",61.5%;and "non-sporty active commuters",25.7%) and among adolescents "active screenies",43.5%;"active academics",35.0%;and "non-sporty active commuters",21.5%) at baseline.Sedentary time increased within each typology among children and adolescents,with no significant differences between typologies.No changes in physical activity were found in any typology among children.In adolescents,physical activity declined within all typologies,with "non-sporty active commuters" declining significantly more than "active screenies" over 3 years.Conclusion:These results support the need for interveation to promote physical activity and prevent increases in sedentary time during childhood and adolescence.Adolescents characterized as "non-sporty active commuters" may require specific interventions to maintain their physical activity over time.
基金supported by the Biopolymer Network Limited(a research collaboration funded by the New Zealand Ministry of Business,Innovation and Employment).
文摘The canola oil industry generates significant waste as canola meal(CM)which has limited scope and applications.This study demonstrates the possibility of valorization of CM as a sustainable natural filler in a biodegradable polymer composite of Poly(lactic acid)(PLA).Generally,interfacial bonding between natural fibers and the polymer matrix in the composite is weak and non-uniform.One possible solution is to derivatize natural fibre to introduce interfacial bond strength and compatibility with the PLA polymer matrix.Here,CM was succinylated in a reactive extrusion process using succinic anhydride at 30 wt%to get 14%derivatization with 0.02 g of-COOH density per g of CM.The CM or succinylated CM at 5 and 15 wt%was co-extruded with amorphous PLA to get composite fibers.CM-PLA and succinylated CM-PLA biocomposites were foamed using a mild and green microcellular foaming process,with CO_(2) as an impregnating agent without any addition of organic solvents.The properties of the foams were analyzed using differential scanning calorimetry(DSC),Dynamic mechanical thermal analysis(DMTA),shrinkage,and imaging.The addition of CM or succinylated CM as a natural filler did not significantly change the glass transition temperature,melting point,percent crystallization,stiffness,and thermal stability of PLA foams.This suggests succinylation(modification)of CM is not a mandatory step for improving interphase compatibility with the amorphous PLA.The new PLA-CM foams can be a good alternative in the packaging industry replacing the existing petroleum-based polymer foams.
