Application of nonlinear fitting and selection of the most fitted equation by AIC in stability test of pharmaceutical ingredients

We proposed a method for objectively selecting the most fitted rate equation among candidate rate equations based on chemical kinetics by both nonlinear regression analysis and Akaike's information criterion (AIC), to express the decrease of pharmaceutical ingredient as an appropriate equation. Pseudo-zero, first, and second-order rate equations were prepared as candidates beforehand, and AIC was introduced for selecting the most fitted rate equation among the candidates. We compared the proposed method to the Weibull method that expressed any decrease patterns as a single equation.

We quantified the contents of thiamine nitrate (VB1) and taurine after storage for one, three, and six months under 40°C-75% relative humidity by high-pressure liquid chromatography. Decrease patterns of each sample were most fitted to one of the candidate rate equations, that is, pseudo-zero, first, and second-order rate equations, respectively, and the degree of fit in the most fitted equation was superior to that of the Weibull method, except for the pseudo-first-order rate equation.

Moreover, we confirmed that the proposed method was considerably precise for estimating the stability of pharmaceuticals by comparing estimated residual rates and confidence intervals to experimental data.     

Pen-to-mime: Pen-based interactive control of a human figure

In this paper a pen-based intuitive interface is presented, that controls a virtual human figure interactively. Recent commercial pen devices can detect not only the pen positions but also the pressure and tilt of the pen. We utilize such information to make a human figure perform various types of motions in response to the pen movements manipulated by the user. The figure walks, runs, turns and steps along the trajectory and speed of the pen. The figure also bends, stretches and tilts in response to the tilt of the pen. Moreover, it ducks and jumps in response to the pen pressure. Using our interface, the user controls a virtual human figure intuitively as if he or she were holding a virtual puppet and playing with it.

In addition to the interface design and implementation, this paper describes a motion generation engine to produce various motion based on varying parameters that are given by the pen interface. We take a motion blending approach and construct motion blending modules with a set of small number of motion capture data for each type of motions. Finally, we present the results from user experiments and comparison with a transitional gamepad-based interface.     

Self-assembly of nano-sized arrays on highly oriented thin films of poly(tetrafluoroethylene)

Self-assembly of nano-sized arrays by casting a dilute solution of a guest material on the friction-transferred poly(tetrafluoroethylene) (FT-PTFE) substrate was newly discovered. Long axis of the rod-like structures forming the arrays is aligned perpendicular to the chain direction of FT-PTFE, and accordingly, the arrays are highly anisotropic. This phenomenon was observed for aqueous or organic solutions of polymers or organic materials. Each rod-like structure forming the arrays is composed of small grains. The arrays in question are formed regardless to the crystallinity of the guest materials. The formation mechanism of the nano-sized arrays is still unclear. However, we guess that they are formed as a result of microscopic flow pattern at the edge of the solution film. The arrays in question may be a new type of dissipative structure.     

Comparison of single sample methods for determination of plasma clearance using 99mTc-MAG3

We compared relationship among three single blood sampling methods which have been proposed for determination of plasma clearance with 99mTc-MAG3. Russell's and Bubeck's algorithms were employed for 48 adults (average age: 53 years) and Bubeck's and Piepsz's algorithms were used in 9 children (average age: 5.8 years). Three methods showed very high correlation among them. However, Russell's and Piepsz's methods were about 1.4 times higher than Bubeck's method in calculating plasma clearance of 99mTc-MAG3. The present study indicates that three methods discussed here are useful for the determination of plasma clearance with 99mTc-MAG3. In addition, Bubeck's method may be preferable as a reference for single plasma sampling method because of common application to adults and children.     

Serum concentrations of apolipoproteins in patients with thyroid dysfunction

We measured serum concentrations of apolipoproteins (apo A-I, A-II, B, C-II, C-III and E) in patients with thyroid disease (hyperthyroidism; n = 44, hypothyroidism; n = 15) and in normal subjects (n = 89). We found that apoA-II, B and C-III concentrations revealed significant difference among three groups of the normal (apoA-II; 31.4 +/- 4.9 mg/dl, apoB; 85.8 +/- 16.3 mg/dl, apoCIII; 7.45 +/- 2.99 mg/dl), hyperthyroidism (apoA-II; 29.8 +/- 5.4, apoB; 63.4 +/- 18.9, apoC-III; 6.28 +/- 2.45) and hypothyroidism (apoA-II; 27.5 +/- 5.3, apoB; 108.0 +/- 30.9, apoC-III; 9.43 +/- 2.74). Thyroid hormones showed clear negative correlation to apoB (r = 0.70, p < 0.001). Furthermore, apoC-III was also found to be negatively correlated with thyroid hormone concentrations (r = 0.47, p < 0.001).     

Direct lattice imageing in single crystals of isotatic polystyrene

Lattice lines with 1.1 nm and 0.55 nm spacings were resolved in isotactic polystyrene (i-PS) single crystals using a conventional transmission electron microscope, equipped for low dose imageing. It is suggested that these crystals may be used as a model for the direct imageing of structural defects in polymer crystals.