ESTIMATION OF AN INDEX OF HYDROPHOBICITY OF DNA INTERIOR USING 5-METHOXYPSORALEN AS A FLUORESCENT PROBE

The index of hydrophobicity of DNA interior was estimated by measuring fluorescence spectra of psoralen derivatives associated with DNA. The environment around 5-MOP associated with DNA was as hydrophobic (D_k = 34) as methanol, suggesting that the molecules reside at the space between the base-pairs in B-form DNA. This is also true for 8-MOP. Thus, planar and aromatic molecules of 5- and 8-MOP are more stable in the interior of DNA than in aqueous medium due to hydrophobic affinity.     

Study of quantitative evaluation of liver volume and accumulation rate of radioactive agent with single photon emission computed tomography

The quantitative evaluation on measurement of liver volume and the hepatic accumulation rate of the radioactive agent were studied with respect to body constitution, background activity and splenic consumption rate, using single photon emission computed tomography (SPECT). The optical cut-off level for liver volume determination was proved to be reasonable as 35%. The background less than 5% had no influence to their clinical estimation with the error of less than 1.6%. The estimation of liver volume was mostly influenced by the splenic activity. When the splenic activity was increased two times of the hepatic activity, the liver volume was determined as 4.2% larger. Calculated counts by SPECT was well correlated with the hepatic activity. This study proved that SPECT was useful for the quantitative evaluation of the liver volume and the hepatic accumulation rate.     

Tumor cell detection method using complement-mediated cytolytic reaction and imaging sensor system

A novel tumor-detection system consisting of complementmediated cytolytic reaction and an image processing system was developed for the simple and rapid determination of tumor cells. The present system consists of a CCD image sensor, image memory board, personal computer, and microscope. When monoclonal antibody 3C4, which is specific to the guinea pig hepatoma L-10, was added to cell suspension, only L-10 cytolysis occurred. Cytolysis caused a decrease in brightness of the cells observed by phase-contrast microscopy. The phase contrast image of the cells before cytolysis was converted to a digitalized signal and stored in computer memory. After cytolysis, a brightness threshold above that of lysed cells was subtracted from the digitalized signal and compared to the signal stored before reaction. L-10 cells in mixed cell suspension were determined specifically by the system. Measurement time was only 2 sec and overall time, including reaction time, was approximately 30 min. Since this method does not require a cell washing process, automation of the whole system is possible.     

Fast determination of thyroid stimulating hormone in human blood serum without chemical preprocessing by using infrared spectroscopy and least squares support vector machines

The least squares support vector machines (LS-SVM) was used to model infrared spectral data for TSH hormone secreted by thyroid, which regulates the basal metabolic rate. This model was used for direct estimation of the content of TSH in blood serum samples, and the results were comparable with those obtained with the conventional analytical method based on chemoluminescence methodology. Excellent agreement was observed between the conventional method and the newly developed calibration model based in analysis of spectral data with LS-SVM. The latter has clear advantages, because it is fast and requires no reagent once the measurements were done directly in the serum by using a simple mid-infrared spectrometer in the ATR mode. An important advantage observed in this calibration method based on LS-SVM is the remarkable capacity to avoid overfitting in the model-building step, that is, the developed method is highly robust.     

Mesoscopic structure and properties of liquid crystalline mesophase pitch and its transformation into carbon fiber

The history and present state of the art in the chemistry of mesophase pitch, which is an important precursor for carbon fiber and other high-performance industrial carbons, are reviewed relative to their structural properties. The structural concepts in both microscopic and macroscopic views are summarized in terms of the sp(2) carbon hexagonal plane as a basic unit common to graphitic materials, its planar stacking in clusters, and cluster assembly into microdomains and domains, the latter of which reflect the isochromatic unit of optical anisotropy. Such a series of structural units is described in a semiquantitative manner corresponding to the same units of graphitic materials, although the size and stacking height of the hexagonal planes (graphitic sheets) are very different. Mesophase pitch is a liquid crystal material whose basic structural concepts are maintained in the temperature range of 250 to 350 degrees C. The melt flow and thermal properties are related to its micro- and mesoscopic structure. The structure of mesophase-pitch-based carbon fiber of high tensile strength, modulus, and thermal conductivity has been formed through spinning, and has inherited the same structural concepts of mesophase pitch. Stabilization settles the structure in successive heat treatments up to 3000 degrees C. Carbonization and graphitization enable growth of the hexagonal planes and their stacking into units of graphite. Such growth is governed and controlled by the alignment of micro- and mesoscopic structures in the mesophase pitch, which define the derived carbon materials as nanostructural materials. Their properties are controlled by the nanoscopic units that are expected to behave as nanomaterials when appropriately isolated or handled.     

Direct and stepwise intercalation of alkylalcohols intoα-zirconium phosphate

Intercalation of alkylalcohols into -zirconium phosphate was investigated at 25°C and/or under reflux.n-Alcohols having two to five carbons and 2-propanol were taken up at 25°C. These alcohols, andn-hexanol and heptanol, also intercalated under reflux.n-Alcohols having eight to eighteen carbon atoms intercalated when a stepwise method was employed. 2-Butanol and tertiary amylalcohols intercalated under reflux using a butanol intercalate as a starting material. Ethanol-to-butanol intercalates were unstable at room temperature, losing alcohols and changing to -zirconium phosphate. The particle size of the -zirconium phosphate did not affect the intercalation of alcohols.     

Convergent synthesis of polycyclic ethers via the intramolecular allylation of alpha-acetoxy ethers and subsequent ring-closing metathesis

The Lewis acid mediated reaction of alpha-acetoxy ethers 15-22 gave the corresponding cyclized products 23, 25, 27, 29, 31, 32, 34, and 36 in good yields with high stereoselectivities. Those cyclized products were subjected to ring-closing metathesis to afford the polycyclic ethers 38-42, 44, and 45 in good yields. The usefulness of the present methodology was demonstrated by the convergent synthesis of the CDEF ring system of brevetoxin B (1) and the CDEFG ring system of gambierol (2).