Picosecond time-resolved fluorescence spectroscopy of hematoporphyrin derivative

The picosecond time-resolved fluorescence decaysI(t)and spectraI(lambda, t)for hematoporphyrin derivative (HPD) in a phosphate buffer saline aqueous solution at different concentrations (8.4 times 10^{-6}sim 8.4 times 10^{-3}M) are measured by a two-dimensional synchroscan streak camera with a mode-locked CW dye laser, and a new emission band (which we call theY-band) is found at high concentration. It is shown that the fluorescence decays composed of fast and slow components at high concentration are due to theY-band (120 ps lifetime) from head-to-tail aggregates including equilibrium dimer and stable dimer, and the usual band (3.6 ns lifetime) from monomer, respectively, and the latter band is dynamically quenched by the Förster type resonance energy transfer from the monomer to the aggregate. Furthermore, the measurement of static fluorescence spectra from human gastric cancers and the surrounding in vivo after HPD injection shows that a band corresponding to theY-band from the aggregate appears at only the cancerous cells.     

Effect of metal-oxide addition on the sintering of β-calcium orthophosphate

The effect of metal-oxide addition (110 mol %) on the sintering of -calcium orthophosphate (–Ca₃(PO₄)₂) was examined by pressureless sintering at 1070 °C for 5 h. The metal-oxide additives used were as follows: (i) monovalent metal-oxides, Li₂O, Na₂O, and K₂O; (ii) divalent metal-oxides, MgO, CaO, SrO, and BaO; (iii) trivalent metal-oxides, Al₂O₃ and Fe₂O₃; and (iv) tetravalent metal-oxides, SiO₂, TiO₂, and ZrO₂. The relative densities of the sintered –Ca₃(PO₄)₂ compacts were reduced with increasing amounts of monovalent and divalent metal-oxide additions, except for the case of MgO addition when the relative density remained with increasing amount of MgO up to 4 mol %. In the case of trivalent metal-oxide additions, the relative density of sintered –Ca₃(PO₄)₂ compact was reduced with increasing amount of Al₂O₃ addition, whereas it was enhanced with increasing amount of Fe₂O₃ addition and reached 98.7% at 10 mol % Fe₂O₃ addition. In the case of tetravalent metal-oxide additions, relative densities of the sintered –Ca₃(PO₄)₂ compacts were slightly reduced with increasing amounts of SiO₂ and ZrO₂ additions, whereas no appreciable changes in the relative density were observed with increasing amount of TiO₂ addition.     

Densification and microstructural developments during the sintering of aluminium silicon carbide

Densification and microstructural developments during the sintering of aluminum silicon carbide (Al₄SiC₄) were examined. Two types of Al₄SiC₄ powders were prepared by the solid-state reactions between: (i) Al, Si, and C at 1600°C for 10 h (designated as Al₄SiC₄(SSR)), and (ii) chemically-vapour deposited ultrafine Al₄C₃ and SiC powders at 1500°C for 4 h (Al₄SiC₄(CVD/SSR)). The specific surface areas of the Al₄SiC₄(SSR) and Al₄SiC₄(CVD/SSR) powders were 2.7 and 15.5 m² · g^–1, respectively. Relative densities of the pressureless-sintered Al₄SiC₄(SSR) and Al₄SiC₄(CVD/SSR) compacts were as low as 60–70% for firing temperatures between 1700°C and 2000°C. The relative densities of Al₄SiC₄(SSR) and Al₄SiC₄(CVD/SSR) compacts could be enhanced using the hot-pressing technique; the relative density of the Al₄SiC₄(SSR) compact hot-pressed at 1900°C for 3 h was 97.0% whereas that of the Al₄SiC₄(CVD/SSR) compact hot-pressed at 1900°C for 1 h attained 99.0%. The former microstructure was composed of plate-like grains of width 10–30 m and thickness 10 m whilst the latter microstructure was comprised of equiaxed grains with a typical diameter of 10 m. Densification of the Al₄SiC₄(CVD/SSR) compacts appeared to be promoted compared to the Al₄SiC₄(SSR) compact and this was attributed to the higher surface area, reduced agglomeration of the starting primary particles, and more homogeneous chemical composition.     

PC-based probabilistic safety assessment in Japan

The role of PC-based programs is becoming important in the area of PSA. The PC-based program QUEST has been developed to perform level-1 PSA at PNC. This program is an effective tool to examine the effects of the change in the plant design and/or operational procedures. Also, as a part of the full scope PSA activity for the prototype liquid metal fast breeder reactor, a systems analysis code network, which involves some PC-based programs, was developed and has been utilized to perform level-1 PSA with less manpower and more consistency. Further, a living PSA tool is currently being developed for the purpose of maintenance of or improvement in operational safety.     

Dielectrophoretic measurement of bacterial motor characteristics

Two methods of measuring bacterial motor characteristics using AC field effects in a microfabricated electrode system are presented. One is the measurement of the external force-velocity characteristics (F-v) of swimming bacteria. Electrostatic orientation of bacteria parallel to the field lines is used to guide the bacterial locomotion along a line. Dielectrophoresis is used to apply an external force, either forward or backward, to the swimming bacteria, and the velocity of locomotion is measured to obtain the F-v curve. The other approach is to measure torque-speed characteristics (T-w) of the motor. Electrorotation is used to apply external torque to the tethered cells, and by changing the applied torque and measuring the rotation speed, the T-ω curve is obtained. The results show that the motor generates approximately constant torque in the measured range of ω (0-100 Hz), regardless of the direction of rotation     

Fabrication of an expanded core fiber having MFD of 40 μmpreserving outer diameter

A thermally-diffused expanded core (TEC) fiber with the mode field diameter (MFD) of 40 μm has been fabricated by improving the diffusion process using an electric furnace. The outer diameter of any TEC fiber is preserved and the excess loss (normal-TEC-normal) is as low as 0.1 dB     

Experimental and clinical studies on the intraperitoneal administration of cis-diamminedichloroplatinum (II) for peritoneal carcinomatosis caused by gastric cancers

The effectiveness of the intraperitoneal administration of cis-diamminedichloroplatinum (II) (DDP) on peritoneal carcinomatosis caused by gastric cancers was evaluated. Seventeen patients were treated with one of three protocols, consisting of the intraperitoneal injection (ip) of DDP at doses of 70 and 110 mg/m2, with or without sodium thiosulfate (STS) rescue. The area under the curve (AUC) of DDP for sufficient anticancer activities against cultured human cell lines in vitro was estimated at 240 micrograms h/ml, which was equivalent to the AUC gained by 110 mg/m2 ip DDP in the clinical studies. The cytotoxic activity of DDP was reduced by approximately 50% with 100-fold STS in the AUC in the experimental studies. However, this was achieved only in urine, and not in either the peritoneal cavity or in plasma in the clinical studies. Three cases of a partial response against peritoneal carcinomatosis were seen from a total of four evaluable cases treated with 110 mg/m2 DDP, and no renal toxicities were observed in those treated with the STS rescue. The results of this study led us to conclude that high-dose ip DDP treatment combined with the STS rescue would be useful chemotherapy against peritoneal carcinomatosis caused by gastric cancers.     

Prediction of the excess enthalpies of mixing of mixtures using the UNIFAC method

The UNIFAC model, developed for binary systems alkanes with n-alcohols, ketones, esters and ethers, and for ternary n-alcohol—n-alcohol—n-alkane systems, gives satisfactory predictions of excess enthalpies of mixing for the systems studied.