A concept of the independent-continuous topological variable is proposed to establish its corresponding smooth model of structural topological optimization. The method can overcome difficulties that are encountered in...A concept of the independent-continuous topological variable is proposed to establish its corresponding smooth model of structural topological optimization. The method can overcome difficulties that are encountered in conventional models and algorithms for the optimization of the structural topology. Its application to truss topological optimization with stress and displacement constraints is satisfactory, with convergence faster than that of sectional optimizations.展开更多
In this paper, we study the extension of isometries between the unit spheresof some Banach spaces E and the spaces C(Ω). We obtain that if the set sm.S_1(E) of all smoothpoints of the unit sphere S_1(E) is dense in S...In this paper, we study the extension of isometries between the unit spheresof some Banach spaces E and the spaces C(Ω). We obtain that if the set sm.S_1(E) of all smoothpoints of the unit sphere S_1(E) is dense in S_1(E), then under some condition, every surjectiveisometry V_0 from S_1(E) onto S_1(C(Ω)) can be extended to be a real linearly isometric map V of Eonto C(Ω). From this result we also obtain some corollaries. This is the first time we study thisproblem on different typical spaces, and the method of proof is also very different too.展开更多
Let E and F be Hilbert spaces with unit spheres S1(E) and S1(F). Suppose that V0 S1(E)→S1(F) is a Lipschitz mapping with Lipschitz constant k=1 such that -V0[S1(E)] V0[S1(E)]. Then V0 can be extended to a real linear...Let E and F be Hilbert spaces with unit spheres S1(E) and S1(F). Suppose that V0 S1(E)→S1(F) is a Lipschitz mapping with Lipschitz constant k=1 such that -V0[S1(E)] V0[S1(E)]. Then V0 can be extended to a real linear isometric mapping V from E into F. In particular, every isometric mapping from S1(E) onto S1(F) can be extended to a real linear isometric mapping from E onto F.展开更多
Vascular smooth muscle cell （VSMC） differentiation and proliferation are two important physiological proc- esses during vascular development. The phenotypic alteration from differentiated to proliferative VSMC contr...Vascular smooth muscle cell （VSMC） differentiation and proliferation are two important physiological proc- esses during vascular development. The phenotypic alteration from differentiated to proliferative VSMC contrib- utes to the development of several major cardiovascular diseases including atherosclerosis, hypertension, resteno- sis after angioplasty or bypass, diabetic vascular complications, and transplantation arteriopathy. Since the VSMC phenotype in these pathological conditions resembles that of developing VSMC during embryonic development, understanding of the molecular mechanisms that control VSMC differentiation will provide fundamental insights into the pathological processes of these cardiovascular diseases. Although VSMC differentiation is usually ac- companied by an irreversible cell cycle exit, VSMC proliferation and differentiation occur concurrently during embryonic development. The molecular mechanisms simultaneously regulating these two processes, however, remain largely unknown. Our recent study demonstrates that cell division cycle 7, a key regulator of cell cycle, promotes both VSMC differentiation and proliferation through different mechanisms during the initial phase of VSMC differentiation. Conversely, Kriappel-like factor 4 appears to be a repressor for both VSMC differentia- tion and proliferation. This review attempts to highlight the novel role of cell division cycle 7 in TGF-β-induced VSMC differentiation and proliferation. The role of K141ppel-like factor 4 in suppressing these two processes will also be discussed.展开更多
This review is part two of three, which will present an update on the classification of gastrointestinal submucosal tumors. Part one treats of the diagnosis and part three of the therapeutic methods regarding gastroin...This review is part two of three, which will present an update on the classification of gastrointestinal submucosal tumors. Part one treats of the diagnosis and part three of the therapeutic methods regarding gastrointestinal submucosal tumors. In the past there has been some confusion as to the classification of gastrointestinal submucosal tumors. Changes in classifications have emerged due to recent advances in mainly immunohistochemistry and electron microscopy. The aim of this paper is to update the reader on the current classification. Literature searches were performed to find information related to classification of gastrointestinal submucosal tumors. Based on these searches the twelve most frequent submucosal tumor types were chosen for description of their classification. The factors that indicate whether tumors are benign or malignant are mainly size and number of mitotic counts. Gastrointestinal stromal tumors are defined mainly by their CD117 positivity. In the future, there should be no more confusion between gastrointestinal stromal tumors and other types of submucosal tumors.展开更多
基金The project supported by State Key Laboratory of Structural Analyses of Industrial Equipment
文摘A concept of the independent-continuous topological variable is proposed to establish its corresponding smooth model of structural topological optimization. The method can overcome difficulties that are encountered in conventional models and algorithms for the optimization of the structural topology. Its application to truss topological optimization with stress and displacement constraints is satisfactory, with convergence faster than that of sectional optimizations.
文摘In this paper, we study the extension of isometries between the unit spheresof some Banach spaces E and the spaces C(Ω). We obtain that if the set sm.S_1(E) of all smoothpoints of the unit sphere S_1(E) is dense in S_1(E), then under some condition, every surjectiveisometry V_0 from S_1(E) onto S_1(C(Ω)) can be extended to be a real linearly isometric map V of Eonto C(Ω). From this result we also obtain some corollaries. This is the first time we study thisproblem on different typical spaces, and the method of proof is also very different too.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 19971046).
文摘Let E and F be Hilbert spaces with unit spheres S1(E) and S1(F). Suppose that V0 S1(E)→S1(F) is a Lipschitz mapping with Lipschitz constant k=1 such that -V0[S1(E)] V0[S1(E)]. Then V0 can be extended to a real linear isometric mapping V from E into F. In particular, every isometric mapping from S1(E) onto S1(F) can be extended to a real linear isometric mapping from E onto F.
基金supported by grants from National Institutes of Health (HL093429 and HL107526 to S.-Y.C.)
文摘Vascular smooth muscle cell （VSMC） differentiation and proliferation are two important physiological proc- esses during vascular development. The phenotypic alteration from differentiated to proliferative VSMC contrib- utes to the development of several major cardiovascular diseases including atherosclerosis, hypertension, resteno- sis after angioplasty or bypass, diabetic vascular complications, and transplantation arteriopathy. Since the VSMC phenotype in these pathological conditions resembles that of developing VSMC during embryonic development, understanding of the molecular mechanisms that control VSMC differentiation will provide fundamental insights into the pathological processes of these cardiovascular diseases. Although VSMC differentiation is usually ac- companied by an irreversible cell cycle exit, VSMC proliferation and differentiation occur concurrently during embryonic development. The molecular mechanisms simultaneously regulating these two processes, however, remain largely unknown. Our recent study demonstrates that cell division cycle 7, a key regulator of cell cycle, promotes both VSMC differentiation and proliferation through different mechanisms during the initial phase of VSMC differentiation. Conversely, Kriappel-like factor 4 appears to be a repressor for both VSMC differentia- tion and proliferation. This review attempts to highlight the novel role of cell division cycle 7 in TGF-β-induced VSMC differentiation and proliferation. The role of K141ppel-like factor 4 in suppressing these two processes will also be discussed.
文摘This review is part two of three, which will present an update on the classification of gastrointestinal submucosal tumors. Part one treats of the diagnosis and part three of the therapeutic methods regarding gastrointestinal submucosal tumors. In the past there has been some confusion as to the classification of gastrointestinal submucosal tumors. Changes in classifications have emerged due to recent advances in mainly immunohistochemistry and electron microscopy. The aim of this paper is to update the reader on the current classification. Literature searches were performed to find information related to classification of gastrointestinal submucosal tumors. Based on these searches the twelve most frequent submucosal tumor types were chosen for description of their classification. The factors that indicate whether tumors are benign or malignant are mainly size and number of mitotic counts. Gastrointestinal stromal tumors are defined mainly by their CD117 positivity. In the future, there should be no more confusion between gastrointestinal stromal tumors and other types of submucosal tumors.
