Radiotherapy for carcinoma of the esophagus in aged patients

One hundred fifty-four patients with esophageal carcinoma were treated with either irradiation alone or irradiation combined with surgery at the University of Occupational and Environmental Health Hospital between January 1980 and February 1992. The number of patients 75 years old and older was 25. In patients 74 years old and younger, the overall five-year survival rate by Kaplan-Meier method was 24.5%. The survival rate was best in the patients who were treated by a combination of irradiation and surgery. In patients 75 years old and older, the one-year survival rate was 59%, and the three-year rate was 20%. Aged patients had a tendency to be worse in performance status, and there was no correlation between treatment modality and survival time. We conclude that radiotherapy is useful for treating esophageal cancer in aged patients particularly when maintenance of the quality of life is considered.     

Analysis of XANES for identification of highly dispersed transition metal oxides on supports

XANES of vanadium and niobium oxide on silica or alumina have been analyzed quantitatively by a deconvolution technique. Based on the results for reference compounds, local structures of supported vanadium and niobium species were identified. The composition was estimated from difference spectra for the samples which consisted of two kinds of species.     

Photocatalytic oxidation of alkane at a steady rate over alkali-ion-modified vanadium oxide supported on silica

Photocatalysts were applied to photocatalytic oxidation of propane in a fixed bed flow reactor. Titanium dioxide exhibited fairly high activity but the deep oxidation was predominant. Silica-supported vanadium oxide (VS) favors the partial oxidation to form propanone and variety of aldehydes and the fast deactivation took place accompanied by reduction of vanadium ions. On the other hand, alkali-ion-modified VS exhibited the highest activity and high selectivity to propanone. The activity was stable because vanadates in alkali-ion-modified VS do not change their structure or are not poisoned by water molecules throughout the reaction. The cleavage of C=C double bond to form aldehydes predominantly proceeded in the case of photo-oxidation of 1-butene over VS while in the case of photo-oxidation of Rb-modified VS, the oxidation of secondary carbon atom to form methyl vinyl ketone is favored. Methyl ethyl ketone was produced at a steady rate over Rb-VS in the photo-oxidation of n-butane.     

Newly Developed Thyristor Chopper Equipment for Electric Railcars

In the chopper control system for electric railcars, it is effective to adopt high operational frequency of the chopper for achievement of the following: 1) decrease of higher harmonic current induced in the trolley wire, 2) reduction of weight for reactors and capacitors in the traction circuit, and 3) improvement of control response. Through development of reverse-conducting thyristors with very short turn-off time and a repulsion type two-phase chopper, we finally realized production of a new standard high-frequency chopper equipment with regenerative braking for 1500-V dc railcars. Technical achievements mentioned previously were completely realized as a result of adoption of high frequency, 660 Hz, in the equipment. The newly developed standard high-frequency chopper equipment for 30 cars were delivered to the Chiyoda Line of Teito Rapid Transit Authority in Tokyo, and they have been operated satisfactorily in revenue service since March 1971. This paper also describes: 1) the chopper circuit using fast-switching reverse-conducting thyristors and series saturable reactors, 2) analysis of commutation circuit and methods of suppressing reapplied forward voltage increasing rate (dv/dt) and shortening commutation period, 3) the composition of the traction circuit including the protection system, such as protection for overvoltage at the regenerative braking, and 4) test results on the Chiyoda Line of Teito Rapid Transit Authority.     

Simulation of chain length recognition observed in formation of inclusion complex

We carried out Brownian dynamics simulations to investigate the mechanism of chain length recognition observed in the formation of inclusion complexes (ICs) between cyclodextrins (CDs) and polymer chains. In our simulations, we used rings and chains as models to represent CDs and polymer chains, respectively. We used two types of chains with different lengths to determine which chain was preferred by the rings to form ICs. At low concentration of rings, we observed that almost all the rings formed ICs with the long chains. Chain length recognition could be reproduced in our simulation, and it occurred because of the difference in the inclusion time between the long chains and the short chains in the ICs. On the other hand, at high concentration of rings, the number of rings forming ICs with the long chains increased, and pseudo-polyrotaxanes (PPRXs) were formed. ICs were also formed with the short chains, because the inclusion time for each ring contained in the PPRXs reduced with an increase in the number of rings therein, and then, the dissociated rings formed ICs with the short chains. As a result, chain length recognition was not observed. From these results, we conclude that the difference in the inclusion time between the rings and the chains controls chain length recognition.     

Characterization of a distributed feedback laser withair/semiconductor gratings embedded by the wafer fusion technique

Wafer fusion between patterned or structured wafers is very useful in the construction of new optical materials and/or devices that have submicrometer-order structures inside semiconductors. In order to investigate the feasibility of wafer fusion for this purpose, a distributed feedback (DFB) laser wafer developed which has air/semiconductor gratings that are embedded using the wafer fusion technique. In this paper, the characteristics of the newly developed DFB laser and the coupling coefficient are investigated. Single-longitudinal-mode oscillation at 1.28 μm is achieved under pulsed conditions at room temperature with a low threshold current density of 1.3 kA/cm², and the coupling coefficient is estimated to he approximately 100 cm^-1. In addition, high-power surface emission (over 6 mW) is demonstrated due to the large difference between the refractive index of air and that of InP. These results indicate the feasibility of applying wafer fusion techniques to form submicrometer structures in semiconductors, and several other applications are expected     

Secondary neutral and ionized particle measurements under MeV-energy ion bombardment

We have measured both secondary neutral and ionized particles from an InSb target under 3.0 MeV Si ion bombardment. Measurements of both ions and neutrals have not been carried out so far in the MeV-energy range. The mass spectra and axial emission energy distributions of secondary particles were investigated. Secondary ions were measured with a linear- and a reflective-type time-of-flight technique, whereas secondary neutral particles were photo-ionized by a UV pulsed laser (ArF: 193 nm) and measured with a reflective-type time-of-flight technique. Different results were obtained for neutral particles in comparison with ionized particles. The mean energy of neutral Sb atoms was much lower than that of neutral In atoms, whereas the mean energies of secondary In and Sb ions were nearly equal.     

Detection of enzymatically generated hydrogen peroxide by metal-based fluorescent probe

We developed a metal-based fluorescent probe for H(2)O(2) called MBFh1, which has an iron complex as a reaction site for H(2)O(2) and a 3,7-dihydroxyphenoxazine derivative as the fluorescent reporter unit. The iron complex reacts quickly with H(2)O(2) to form oxidants, and then the oxidants convert the closely appended nonfluorescent 3,7-dihydroxyphenoxazine moiety to resorufin in an intramolecular fashion. The quick response to H(2)O(2) allows us to plot the enzymatic evolution of H(2)O(2). A combination of N-acetyl-3,7-dihydroxyphenoxazine and horseradish peroxidase has been frequently used to detect enzymatically generated H(2)O(2), but this method has interference with phenol derivatives. The use of MBFh1 overcomes this drawback.