-In plant cell culture on large scale,we have studied two types of biore-actors-Airlift reactor and stirred tank reactor-under the same volume and work conditions. It shows that the value of volumetric oxygen transfer...-In plant cell culture on large scale,we have studied two types of biore-actors-Airlift reactor and stirred tank reactor-under the same volume and work conditions. It shows that the value of volumetric oxygen transfer coefficient K1a in airlift is a little higher than that in stirred tank reactor at the aeration rate of 0.1~0.3vvm:the mixing time tm in both of them is small respect to the culture period.The shear stress in stirred tank reactor is higher than that in airlift reactor,but its influence is not negative at all. When the value or the shear stress in medium is low-er than a critical value,it will be favorable to the dispersion of cells and promotes the growth of cells.This result is verified in the experiment we have conducted in the airlift reactor and stirred tank reactor.展开更多
The prominent role Ca^2＋ ion plays as a major small biological messenger is fascinating. There are many physiologically important ions, such as Na^＋, K^＋, H^＋, Cl^-, Ca^2＋, Mg2＋, Fe^3＋, and PO4^3- that particip...The prominent role Ca^2＋ ion plays as a major small biological messenger is fascinating. There are many physiologically important ions, such as Na^＋, K^＋, H^＋, Cl^-, Ca^2＋, Mg2＋, Fe^3＋, and PO4^3- that participate in cell signaling. Among them, monovalent ions primarily contribute to rapid electrical signaling, while multivalent ions generally act as a co-factor for chemical reactions by associating with the host molecule through electrostatic or covalent interactions. Ca^2＋ plays both roles. Its transmembrane influx supports the plateau phase of cardiac action potential and helps set the speed of pacemaker potential.展开更多
文摘-In plant cell culture on large scale,we have studied two types of biore-actors-Airlift reactor and stirred tank reactor-under the same volume and work conditions. It shows that the value of volumetric oxygen transfer coefficient K1a in airlift is a little higher than that in stirred tank reactor at the aeration rate of 0.1~0.3vvm:the mixing time tm in both of them is small respect to the culture period.The shear stress in stirred tank reactor is higher than that in airlift reactor,but its influence is not negative at all. When the value or the shear stress in medium is low-er than a critical value,it will be favorable to the dispersion of cells and promotes the growth of cells.This result is verified in the experiment we have conducted in the airlift reactor and stirred tank reactor.
文摘The prominent role Ca^2＋ ion plays as a major small biological messenger is fascinating. There are many physiologically important ions, such as Na^＋, K^＋, H^＋, Cl^-, Ca^2＋, Mg2＋, Fe^3＋, and PO4^3- that participate in cell signaling. Among them, monovalent ions primarily contribute to rapid electrical signaling, while multivalent ions generally act as a co-factor for chemical reactions by associating with the host molecule through electrostatic or covalent interactions. Ca^2＋ plays both roles. Its transmembrane influx supports the plateau phase of cardiac action potential and helps set the speed of pacemaker potential.
