The stress-strain behavior and copper are studied by the molecular dynamics incipient yield surface of nanoporous single crystal （MD） method. The problem is modeled by a periodic unit cell subject to multi-axial loa...The stress-strain behavior and copper are studied by the molecular dynamics incipient yield surface of nanoporous single crystal （MD） method. The problem is modeled by a periodic unit cell subject to multi-axial loading. The loading induced defect evolution is explored. The incipient yield surfaces are found to be tension-compression asymmetric. For a given void volume fraction, apparent size effects in the yield surface are predicted： the smaller behaves stronger. The evolution pattern of defects （i.e., dislocation and stacking faults） is insensitive to the model size and void volume fraction. However, it is loading path dependent. Squared prismatic dislocation loops dominate the incipient yielding under hydrostatic tension while stacking-faults are the primary defects for hydrostatic compression and uniaxial tension/compression.展开更多
Cellular space-charge polymer film, also called cellular piezoelectret, has very large piezoelectric effect due to their unique microvoid structure. In this article, the cellular piezoelectret film is considered to be...Cellular space-charge polymer film, also called cellular piezoelectret, has very large piezoelectric effect due to their unique microvoid structure. In this article, the cellular piezoelectret film is considered to be a periodic composite material with closed-cell microvoids aligned periodically. Three dimensional finite element modeling is carried out to obtain the effective elastic modulus and piezoelectric coefficients. Sensitivity analysis was presented by modeling the effec- tive electromechanical properties with different individual variable, including material constants and void shape parameters. By assuming a relation between void shape and void volume fraction, the finite element model can simulate quite well the inflation experiments of the voided charged Polypropylene film published in literature. Finally, the finite element model is used to explore the voided charge polymer film with non-uniform distribution of the trapped charges on the internal surface of voids. It was found that the resultant overall piezoelectric coefficients will be more significant if charges are closely gathered in the central area, and sparse in the around area of the internal surface of voids.展开更多
Lipin proteins including Lipin 1–3 act as transcriptional co-activators and phosphatidic acid phosphohydrolase enzymes,which play crucial roles in lipid metabolism.However,little is known about the function of Lipin3...Lipin proteins including Lipin 1–3 act as transcriptional co-activators and phosphatidic acid phosphohydrolase enzymes,which play crucial roles in lipid metabolism.However,little is known about the function of Lipin3 in triglyceride(TG)metabolism.Here,we identified a novel mutation(NM_001301860:p.1835A>T/p.D612V)of Lipin3 in a large family with hypertriglyceridemia(HTG)and obesity through whole-exome sequencing and Sanger sequencing.Functional studies revealed that the novel variant altered the half-life and stability of the Lipin3 protein.Hence,we generated Lipin3 heterozygous knockout(Lipin3-heKO)mice and cultured primary hepatocytes to explore the pathophysiological roles of Lipin3 in TG metabolism.We found that Lipin3-heKO mice exhibited obvious obesity,HTG,and non-alcoholic fatty liver disorder.Mechanistic study demonstrated that the haploinsufficiency of Lipin3 in primary hepatocytes may induce the overexpression and abnormal distribution of Lipin1 in cytosol and nucleoplasm.The increased expression of Lipin1 in cytosol may contribute to TG anabolism,and the decreased Lipin1 in nucleoplasm can reduce PGC1α,further leading to mitochondrial dysfunction and reduced TG catabolism.Our study suggested that Lipin3 was a novel disease-causing gene inducing obesity and HTG.We also established a relationship between Lipin3 and mitochondrial dysfunction.展开更多
基金supported by the National Natural Science Foundation of China (Nos10425210 and 10832002)the National Basic Research Program of China (No2006CB601202)the National High Technology Research and Development Program of China (No2006AA03Z519)
文摘The stress-strain behavior and copper are studied by the molecular dynamics incipient yield surface of nanoporous single crystal （MD） method. The problem is modeled by a periodic unit cell subject to multi-axial loading. The loading induced defect evolution is explored. The incipient yield surfaces are found to be tension-compression asymmetric. For a given void volume fraction, apparent size effects in the yield surface are predicted： the smaller behaves stronger. The evolution pattern of defects （i.e., dislocation and stacking faults） is insensitive to the model size and void volume fraction. However, it is loading path dependent. Squared prismatic dislocation loops dominate the incipient yielding under hydrostatic tension while stacking-faults are the primary defects for hydrostatic compression and uniaxial tension/compression.
基金Department of Transport/Sun GrantUS Department of Agriculture/ Department of Energy+4 种基金Minnesota Legislative-Citizen Commission on Minnesota ResourcesMetropolitan Council Environmental ServicesUniversity of Minnesota MNDrive programsUniversity of Minnesota Center for BiorefiningChina Scholarship Council (CSC) for their financial support for this work
基金Project supported by the National Natural Science Foundation of China (Nos. 11072179 and 11090334)the Shanghai Leading Academic Discipline Project (No. B302)
文摘Cellular space-charge polymer film, also called cellular piezoelectret, has very large piezoelectric effect due to their unique microvoid structure. In this article, the cellular piezoelectret film is considered to be a periodic composite material with closed-cell microvoids aligned periodically. Three dimensional finite element modeling is carried out to obtain the effective elastic modulus and piezoelectric coefficients. Sensitivity analysis was presented by modeling the effec- tive electromechanical properties with different individual variable, including material constants and void shape parameters. By assuming a relation between void shape and void volume fraction, the finite element model can simulate quite well the inflation experiments of the voided charged Polypropylene film published in literature. Finally, the finite element model is used to explore the voided charge polymer film with non-uniform distribution of the trapped charges on the internal surface of voids. It was found that the resultant overall piezoelectric coefficients will be more significant if charges are closely gathered in the central area, and sparse in the around area of the internal surface of voids.
基金supported by the National Natural Science Foundation of China(Nos.82170598,82000427,and 81970403)the Key Research and Development Program of Hunan Province(No.2022sk2034)the Natural Science Foundation of Hunan Province(Nos.2022JJ30058 and 2023JJ20078).
文摘Lipin proteins including Lipin 1–3 act as transcriptional co-activators and phosphatidic acid phosphohydrolase enzymes,which play crucial roles in lipid metabolism.However,little is known about the function of Lipin3 in triglyceride(TG)metabolism.Here,we identified a novel mutation(NM_001301860:p.1835A>T/p.D612V)of Lipin3 in a large family with hypertriglyceridemia(HTG)and obesity through whole-exome sequencing and Sanger sequencing.Functional studies revealed that the novel variant altered the half-life and stability of the Lipin3 protein.Hence,we generated Lipin3 heterozygous knockout(Lipin3-heKO)mice and cultured primary hepatocytes to explore the pathophysiological roles of Lipin3 in TG metabolism.We found that Lipin3-heKO mice exhibited obvious obesity,HTG,and non-alcoholic fatty liver disorder.Mechanistic study demonstrated that the haploinsufficiency of Lipin3 in primary hepatocytes may induce the overexpression and abnormal distribution of Lipin1 in cytosol and nucleoplasm.The increased expression of Lipin1 in cytosol may contribute to TG anabolism,and the decreased Lipin1 in nucleoplasm can reduce PGC1α,further leading to mitochondrial dysfunction and reduced TG catabolism.Our study suggested that Lipin3 was a novel disease-causing gene inducing obesity and HTG.We also established a relationship between Lipin3 and mitochondrial dysfunction.
