Objective To investigate the changes of left atrial(LA) segmental strains by using threedimension speckle tracking imaging(3D-STI),and to investigate the feasibility of 3D-STI for assessment of LA myocardial strains in healthy adults.Methods A total of 60 healthy subjects were enrolled.Apical fullvolume images were acquired in all subjects and then were analyzed by off-line 3D-STI analysis software.The software divided LA into 16 segments automatically,they were six walls (anterior,anterior-septal,posterior-septal,inferior,anterior-lateral,posterior-lateral) in basal and middle levels,and four walls (anterior,septal,inferior,lateral) in roof level.The peak longitudinal strain (PALS),peak circumferential strain(PACS),peak area strain(PAAS),the time to peak longitudinal strain(TPLS),the time to peak circumferential strain(TPCS) and the time to peak area strain(TPAS) of left atrial by 3D-STI were obtained and compared.Results ①Compared with the four walls in roof level and anterior-lateral,posterior-lateral walls in middle level,PALS of corresponding walls in basal level were significantly increased (P ＜0.05).PALS of posterior-septal,inferior and posterior-lateral walls in middle level were significantly increased than septal,inferior,and lateral walls of roof level (P ＜0.05).PACS and PAAS of all walls in roof level were significantly increased,as compared with that of corresponding walls in middle and basal levels,and the PACS of posterior-septal wall in basal level were lower than that in middle level(P ＜0.05).②There were no significant differences in PALS,PACS,PAAS between different walls within one level(P ＜0.05).③TPLS,TPCS,TPAS of septal wall were significantly lower than that of lateral wall.TPLS of anterior wall,TPCS and TPAS of inferior wall were significantly lower than that of lateral wall(P ＜0.05).Conclusions 3D-STI is a feasible skill to assess LA myocardial strains in healthy subjects.

Poly lactic acid (PLA)/Poly (butyleneadipate-co-terephthalate)(PBAT) and glyceryl triacetate (GTA) blend were prepared by torque rheometer, and the effect of GTA on thermodynamical performance, mechanical properties and microstructure of PLA/PBAT composites were studied using differential scanning calorimeter(DSC), dynamic mechanical analysis(DMA), universal testing machine, impact testing machine and scanning electron microscope(SEM). After adding GTA, Tg values of the two phases gradually became closer, blends cold crystallization temperature and melting temperature decreased. When with 3 phr GTA, the dispersed phase particle size of PLA/PBAT blend decreased. Mechanics performance test showed that the elongation at break and impact strength of the PLA/PBAT blend was greatly increased with 3 phr GTA, and the elongation at break increased 2.6 times, improved from 17.7% to 64.1%.
Acetates ; chemistry ; Calorimetry, Differential Scanning ; Crystallization ; Lactic Acid ; Polyesters ; chemistry ; Polymers ; Temperature

In this review, we presented the industrial status of biomanufactured polyhydroxyalkanoates (PHA), including poly (3-hydroxybutyrate) (PHB), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly (3-hydroxybutyrate-co-4-hydroxybutyrate) (P3/4HB)), and poly (3-hydroxybutyrate-3-hydroxycaproate) (PHBH). A lot of modification studies, aimed at solving problems of poor thermal stability, narrow processing window and other drawbacks of PHA, are discussed. The properties of PHA can be optimized by using proper modification method, in order to expand its applications.
3-Hydroxybutyric Acid ; Biotechnology ; Hydroxybutyrates ; Polyesters ; Polyhydroxyalkanoates ; chemistry

In recent years, bio-based materials are becoming a new dominant industry leading the scientific and technological innovation, and economic development of the world. We reviewed the new development of bio-based materials industry in China, analyzed the entire market of bio-based materials products comprehensively, and also stated the industry status of bio-based chemicals, such as lactic acid, 1,3-propanediol, and succinic acid; biodegradable bio-based polymers, such as co-polyester of diacid and diol, polylactic acid, carbon dioxide based copolymer, polyhydroxyalknoates, polycaprolactone, and thermoplastic bio-based plastics; non-biodegradable bio-based polymers, such as bio-based polyamide, polytrimethylene terephthalate, bio-based polyurethane, and bio-based fibers.
Biomass ; Biotechnology ; China ; Lactic Acid ; Phthalic Acids ; Plastics ; Polyesters ; Polyhydroxyalkanoates ; Polymers ; Propylene Glycols ; Succinic Acid