Ultracentrifuge UC

The biophysical experiments of our cooperation partners focus mainly on two different techniques - a rough estimate of aggregation prevention is found by differential ultracentrifugation (UC), but more detailed information about the kinetics and aggregate size comes from fluorescence correlation spectroscopy (FCS) [24]. 

From the great variety of methods for the determination of protein binding three separation methods, equilibrium dialysis (ED), ultrafiltration (UF), and ultracentrifugation (UC) and a non-conventional method with the binding to immobilized proteins has been chosen. The first methods are undoubtedly the most widely used because of their simplicity and general applicability to many different systems. Other methods e.g. size exclusion chromatography, capillary electrophoresis, or spectroscopic methods have been not described. Oravcova et al. (1996) gives a comprehensive review and comparison for these applications. 

The ultracentrifugation (UC) method achieves separation of free and protein bound drugs by centrifugation of the sample in a tube without a membrane. It makes use of the fact that sedimentation of solutes depends upon their molecular weight. The first time Steinberg and Schachmann (1966) demonstrated theoretically and practically the potential of the method. 

Tables III, IV, and V show ultraviolet absorption-based determinations of concentrations after centrifugation (C), ultracentrifugation (UC) and ultrafiltration (UF). The effect of the order of mixing on size of dispersed particles, as evidenced by different responses to the same treatment, is plain in Table III.

Table IV. Ultrafiltration (UF) and ultracentrifugation (UC) tests of surfactant solubility and particle size of surfactant-water systems, which were stirred well and allowed to settle for two days at 25°C.

Fig. 3.13. Plasma protein fractionation by a preparative ultracentrifugation (UC) method (according to Seidel, 1971)...

The significance of the complex sequence of events involved in the formation, transfer, and clearance of plasma lipoprotein CE is demonstrated dramatically by several inborn errors of metabolism. One such error is familial LCAT deficiency [67]. In this disease, as well as in diseases associated with acquired LCAT deficiency, LCAT activity in the plasma is abnormally low, and many hpoprotein and tissue abnormalities are observed. The content of UC and PC is abnormally high, and the molar ratio of UC to PC in the hpoproteins is also high, sometimes reaching a value of nearly 2 1. In association with these abnormahties, most lipoproteins show an abnormally low content of CE. In addition, there are abnormahties in the distribution and/or concentration of apolipoproteins AI, All, B, C, and E disc-shaped HDL and unusually small spherical HDL are seen and multilamehar vesicles containing UC and PC are usually present in the LDL fraction obtained by preparative ultracentrifugation. These abnormahties all seem to depend on the LCAT deficiency they are altered toward normal when patient plasma is incubated with LCAT in vitro. 

In the nanosized Li4Ti50i2 particles, it is expected that Li" ions diffuse and electrons migrate in distances reduced by a factor of 1/1,000 or less as compared with the distances in normal micron-order LLjTi50i2 particles. Further, in the composite, electron paths are effectively formed in the electrode of nanosized LLjTi50i2 particles On the basis of these expectations, the authors synthesized a composite (nc-Li4Ti50i2/CNF) by means of a new method referred to as ultracentrifugal force (UC) method [20]. Specifically, the composite... 

The nc-Li4Ti50i2 negative electrode was developed to have a unique nanostructure that can operate at unusually high current densities. Nanocrystalline s attached onto carbon nanofibers were prepared by a unique technique (UC method) of a mechanochemical sol-gel reaction under ultracentrifugal force field [22], followed by an instantaneous heat treatment under vacuum for very short duration... 

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