Ultracentrifugation continuous

When used properly, ultracentrifugation continues to be our major means of determining molecular weight values for humic substances using sedimentation velocity and other techniques. Indeed, centrifugation studies with humic substances have usually centered upon molecular weight measurements. 

Updates to SpinPro continue as new rotors and new techniques are developed or as inadequacies are found. New expert systems techniques, such as the ability to incorporate the principles of a problem domain, rather than just the experience of the expert, should give SpinPro the ability to design procedures for novel problems and to explain its reasoning. The updates insure that SpinPro will be a repository of knowledge about the current state of ultracentrifugation SpinPro s expertise should continue to improve. Furthermore, the expert remains gainfully employed as a final arbitrator on the inclusion or exclusion of any new knowledge. 

Specialty rotors permit ordinary botde centrifuges to achieve some of the results previously considered possible only in ultracentrifuges. A modified zonal rotor, shown in Figure 9, permits collection of sediment using continuous addition of feed and discharge of centrate. 

During the last half century, Japanese encephalitis has been recognized as an important arboviral disease in man in Japan, China, Korea, Thailand, India, Nepal, Sri Lanka, and Vietnam. In 1954, Japanese encephalitis vaccine of the mouse brain type for human use was licensed in Japan. However, there was strong criticism of mouse brain vaccine, which has continued for many years. Therefore, in 1965, the Nippon Institute of Biological Products and the Biken Foundation implemented more advanced purification procedures, such as alcohol precipitation and ultracentrifugation. 

Density gradient ultracentrifugation is used to measure hpoprotein subclasses it is performed in a vertical rotor with measurement of cholesterol continuously in the fractions eluted from the gradient. Mathematical curve resolution derives the component lipoprotein profiles and allows calculation of their cholesterol concentrations. The method can determine concentrations of VLDL, IDL, LDL, Lp(a), and HDL cholesterol. LDL cholesterol subclasses can be expressed separately or combined to give a measurement similar to that provided by the Friedewald equation or beta-quantification. A disadvantage is that the procedure is technically demanding and requires instrumentation not usually available in clinical laboratories. 

Griffith, O.M. (1986). Techniques of Preparative, Zonal and Continuous Flow Ultracentrifugation. Beckman Instruments, Palo Alto, California. 

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