It is difficult to visualize a complex crystal structure that has many ions or atoms in the unit lattice by using the atom sphere. The Windows95/98/NT application which displays crystal structure using the coordination polyhedron, was developed using the Borland C++ Builder4. Display of complex crystal structures such as silicate or complex oxide can be simplified by using the coordination polyhedron. This application can use the CIF (Crystallographic Information File) offered from ICSD (Inorganic Crystal Structure Database), (CD- ROM edition) as the crystal structure data. The crystal structure can be displayed by the 3D graphics of high quality by VRML file that was saved by this application. It was found that the zeolite has many big cavities when the crystal structure was displayed with coordination polyhedra (Figure 8). It is reported that the crystal structure of Nb2Zr6O17 contains the octahedron, the sevenfold coordinated polyhedron and the square antiprism, and it could be confirmed by this application (Figures 10, 11). Furthermore, the user can visually appreciate crystal structures by the overlapped display mode of a couple of different crystal structures or the display mode of multiple cells.
Tea catechins and related compounds, (-)-Epicatechin gallate and (-)-Epigallocatechin ga
llate, which have a galloyl moiety at the C-3 position (see Figure 1), show higher reactivity of hyd
roxylmethylation than others. We performed theoretical calculations on 5 tea catechins by the semi-e
mpirical molecular orbital method. It is found that introduction of a galloyl moiety makes HOMO
localize at the C-6 and C-8 positions. These variations of orbital energies lead to a high reactivi
ty. It is suggested that the introduction of functional groups that have a large -electron system in
to tea catechins raises the reactivity of hydroxylmethylation.
A quality control system has been developed for the purpose of the improvement of the quality of 1H-NMR spectral databases. The system, SpecQC, compares the data of a compound in the database with the predicted 1H-NMR chemical shifts for the compound using a knowledge base and verifies the quality of the data. The SpecQC system is able to evaluate a large number of data in the database in a batch mode and to divide them into three classes according to quality. It makes it easy to recognize erroneous data and to maintain a high quality database by means of modification.
Six hydrodynamic models of typical linear chemical/pharmaco-kinetics (one containing a zero-order process) were simulated easily and realistically by computer. In particular, the pharmacokinetic simulation of a two-compartment open model with rapid intravenous injection provided many suggestions. The computer simulations were exact, and they could represent flow rate (kinetic velocity) exactly. Furthermore, the simulations could simultaneously show ordinary graphs of the variations in drug amount/concentration versus time. Therefore, they are superior to the actual hydrodynamic models in studying chemical/pharmaco-kinetics.
Multimedia have been thought to be most successful in illustrating concepts, and least successful when applied to the derivation of equations. We have developed interactive animation of hydrogen atomic orbitals using a software called QuickTime Virtual Reality (QTVR). The use of these pictures was shown to increase student interest and participation in the process to understand the mutual relation of the shapes with the mathematical functions of atomic orbitals.