The effect of involute contact ratio on the torsional vibration behavior ofspur gear-pair is studied analytically through a mass-spring model. The tooth stiffness in model notonly has a relation with time, as many pri...The effect of involute contact ratio on the torsional vibration behavior ofspur gear-pair is studied analytically through a mass-spring model. The tooth stiffness in model notonly has a relation with time, as many prior studies presented, but, more important, with involutecontact ratio (ICR) as well. The ICR embodies its impact on the spur gear's dynamic performancethrough changing the proportion of tooth stiffness when there are n+1 teeth in contact to toothstiffness when there are n teeth in contact. A couple of curves about impact of ICR on the gear'sdynamic performance are presented, and they clearly demonstrate that the model can accuratelydescribe the effects of ICR on dynamic transmission error. Finally, some conclusions useful toreduce vibration and noise of gear-pair are proposed.展开更多
Uterine natural killer(uNK)cells,sharing many characters with peripheral blood natural killer(pNK)cells,are a major uterine lymphocyte population at early gestational stages during normal pregnancy in placental mammal...Uterine natural killer(uNK)cells,sharing many characters with peripheral blood natural killer(pNK)cells,are a major uterine lymphocyte population at early gestational stages during normal pregnancy in placental mammals. The functions of uNK cells include cytokine production and cytotoxcity that are regulated by signals through activating and inhibitory receptors.UNK cells differ from pNK cells however and contribute to the structural changes that accompany the differentiation of the maternal-fetal interface.Immunological mechanisms must provide a balanced environment for uNK cell proliferation,differentiation and activation through intricate signaling pathways.An improved knowledge of mechanisms regulating uNK cells development and the cytokine network at the maternal-fetal interface of mice and humans might be useful to harness the power of these cells for maintenance of pregnancy.Cellular & Molecular Immunology.2005;2(2):123-129.展开更多
Interleukin 12(IL-12)and/or interleukin 18(IL-18)gene ablated mice were applied for the investigation of the tissue expression of interferon γ(IFN-γ).For IL-12^(-/-),IL-18^(-/-),IL-12^(-/-)/18^(-/-) and wt mice,repr...Interleukin 12(IL-12)and/or interleukin 18(IL-18)gene ablated mice were applied for the investigation of the tissue expression of interferon γ(IFN-γ).For IL-12^(-/-),IL-18^(-/-),IL-12^(-/-)/18^(-/-) and wt mice,reproductive performance were recorded and IFN-γ concentrations in heart,lung,liver,spleen,kidney and serum were quantified by ELISA. There were no significant differences of IFN-γ in heart,lung and kidney between 4 strains although control group was higher.It was observed that for IL-12^(-/-) mice,compared with other 3 groups,IFN-γ in liver and spleen were decreased(p<0.05)and reproductive performance appeared to be impaired.Serum IFN-γ level of IL-12^(-/-)/18^(-/-) mice was significantly higher(p<0.05).It was showed that IFN-γ productions under the normal condition were independent upon IL-12 and IL-18,its expressions in various tissues were different,and optimal IFN-γ is necessary for the normal growth and development of mammals.This study is helpful for clinical cytokines therapy.Cellular & Molecular Immunology.2005;2(1):68-72.展开更多
文摘The effect of involute contact ratio on the torsional vibration behavior ofspur gear-pair is studied analytically through a mass-spring model. The tooth stiffness in model notonly has a relation with time, as many prior studies presented, but, more important, with involutecontact ratio (ICR) as well. The ICR embodies its impact on the spur gear's dynamic performancethrough changing the proportion of tooth stiffness when there are n+1 teeth in contact to toothstiffness when there are n teeth in contact. A couple of curves about impact of ICR on the gear'sdynamic performance are presented, and they clearly demonstrate that the model can accuratelydescribe the effects of ICR on dynamic transmission error. Finally, some conclusions useful toreduce vibration and noise of gear-pair are proposed.
文摘Uterine natural killer(uNK)cells,sharing many characters with peripheral blood natural killer(pNK)cells,are a major uterine lymphocyte population at early gestational stages during normal pregnancy in placental mammals. The functions of uNK cells include cytokine production and cytotoxcity that are regulated by signals through activating and inhibitory receptors.UNK cells differ from pNK cells however and contribute to the structural changes that accompany the differentiation of the maternal-fetal interface.Immunological mechanisms must provide a balanced environment for uNK cell proliferation,differentiation and activation through intricate signaling pathways.An improved knowledge of mechanisms regulating uNK cells development and the cytokine network at the maternal-fetal interface of mice and humans might be useful to harness the power of these cells for maintenance of pregnancy.Cellular & Molecular Immunology.2005;2(2):123-129.
文摘Interleukin 12(IL-12)and/or interleukin 18(IL-18)gene ablated mice were applied for the investigation of the tissue expression of interferon γ(IFN-γ).For IL-12^(-/-),IL-18^(-/-),IL-12^(-/-)/18^(-/-) and wt mice,reproductive performance were recorded and IFN-γ concentrations in heart,lung,liver,spleen,kidney and serum were quantified by ELISA. There were no significant differences of IFN-γ in heart,lung and kidney between 4 strains although control group was higher.It was observed that for IL-12^(-/-) mice,compared with other 3 groups,IFN-γ in liver and spleen were decreased(p<0.05)and reproductive performance appeared to be impaired.Serum IFN-γ level of IL-12^(-/-)/18^(-/-) mice was significantly higher(p<0.05).It was showed that IFN-γ productions under the normal condition were independent upon IL-12 and IL-18,its expressions in various tissues were different,and optimal IFN-γ is necessary for the normal growth and development of mammals.This study is helpful for clinical cytokines therapy.Cellular & Molecular Immunology.2005;2(1):68-72.
