A Barium-Titanate-Ceramics Capacitive-Type EEG Electrode

A capacitive-type electrode using barium titanate ceramics is described. This electrode is not affected by the polarization potential. Because its surface is chemically inactive and mechanically strong, its noise voltage is minimum from the beginning of its installation. This device is especially suitable for EEG recording.     

Preoperative evaluation of the limitation of hepatic resection using 99mTc-GSA (galactosyl human serum albumin) scintigraphy

Preoperative evaluation of the operative indication of hepatic resection using the parameters obtained by 99mTc-GSA scintigraphy has been done. In particular, the accurate evaluation of the postoperative hepatic functional reserve essentially depends on these parameters. In the present study, a preoperative evaluation of postoperative hepatic functional reserve using 99mTc-GSA scintigraphy was performed in our operated cases retrospectively. PATIENTS AND METHODS: Thirty-eight patients who underwent hepatic resection were studied on 99mTc-GSA scintigraphy before and after operation. These patients were divided into two groups. Group A; had no postoperative complications (n = 31). Group B; had some postoperative complications (n = 7). Preoperative parameters of 99mTc-GSA liver scintigraphy (HH15, LU15) were calculated from the activities of liver and cardiac ROIs at 5 and 15 minutes after injection. The resection ratio (RR) was obtained by comparing the liver volumes which were calculated from the pre- and postoperative SPECT studies. The resectability indices (Res) were as follows: Res (LU15) = LU15 x (100-RR(%)/100, Res (HH15) = (1/HH15) x (100-RR (%)/100. RESULTS: There were statistically significant differences in the distribution of Res between A and B groups (p = 0.002, Mann-Whitney test). The values of Res, of which half of patients have complication, were 1.10 (Res (HH15)) and 16.4 (Res (LU15)). CONCLUSION: The resectability indices using 99mTc-GSA liver scintigraphy are useful for the preoperative evaluation of the limitation of hepatic resection.     

Three-phase and zero-phase current sensors using hall ICs

Three-phase current sensors are required in power-line distribution systems to monitor currents and protect systems from possible failures. Zero-phase current sensors also are required to detect leakage currents between power lines and the earth, thus preventing accidents such as a fire. This paper describes new three-phase and zero-phase current sensors which are based on a zero method. The sensors consist of Hall ICs, coils, and electronic circuits; no magnetic cores are used. The three-phase current sensor provides measurements of currents from 0.8 A to 720 A with excellent accuracy, while the zero-phase current sensor provides measurements from 90 mA to 20 A. The output signal levels are suitable for microprocessor-based metering and control systems. The sensors are relatively small and lightweight compared to a conventional current transformer (CT). Moreover, they withstand excess currents and do not yield burning or deterioration. They do not require expensive components so they have an advantage in cost compared to an optical-fiber current transformer.     

Clinical pharmacokinetics of carboplatin and MCNU in malignant brain tumor and normal brain tissues

We measured the concentrations of MCNU and CBDCA in the serum, brain tumor and normal brain tissue. Six patients with malignant glioma were treated with intravenous chemotherapy using 80mg/m2 MCNU and 300mg/m2 CBDCA during surgery. After drug administration, specimens of serum, tumor and normal brain tissue were collected every 30 min and then the drug concentration in each sample was measured. The highest MCNU levels in all samples were obtained immediately after administration which followed by gradual decrease. On the contrary, the mean CBDCA levels in the tumor and normal tissue remained almost at a constant level, although serum CBDCA level declined rapidly as MCNU. As expected, MCNU seemed to have advantages in the treatment of brain tumors as it distributed with higher concentration in the tumor tissue than in the serum and normal brain tissue. On the contrary, CBDCA in the tumor tissue did not exceed the concentration in the serum. Nevertheless, it remained longer in the tumor tissue with a constant level, suggesting that CBDCA can achieve an effective area under the concentration versus time curve (AUC) in the brain tumor tissue to kill tumor cells.     

A single p-i-n junction amorphous-silicon solar cell withconversion efficiency of 12.65%

A conversion efficiency of 12.65% was obtained at AM-1.5, 100 mW/cm² for a single p-i-n junction amorphous-Si solar cell of 1.05 cm², with a glass/SnO₂/p-i-n/back-electrode structure. The solar cell had a short-circuit current of 19.13 mA/cm², an open-circuit voltage of 0.885 V, and a fill factor of 74.7%. The reason why the efficiency of the produced solar cell was enhanced by hot-annealing treatment is considered to be due to the reduction of the minute leaks caused by the pinhole treatment and the reduction of the number of pinholes by reverse-bias annealing treatment. It is believed that because of the minute irregularities on the surface of SnO₂, the diffuse light in the solar cell increased the effective optical length in the i layer. Therefore the collection efficiency in the long-wavelength region was enhanced     

The complexity of some decision problems about two-dimensional array grammars

The complexity of several decision problems concerning two-dimensional isometric array grammars (IAG) is studied. Because of the two-dimensional and the “isometric” properties of IAG, many decision problems become very hard to solve even for regular array grammars (RAG), the lowest subclass of IAG in the Chomsky-like hierarchy. In this paper, it is shown that the membership problems for RAGs and for context-free array grammars (CFAG) are both NP-complete. The emptiness problem and the equivalence problem for RAGs are shown to be undecidable.     

Characteristics and behavior of the interfacial wave on the liquid film in a vertically upward air-water two-phase annular flow

The behavior of individual interfacial waves on liquid film in vertically upward air-water annular flows has been visualized, observed and analyzed by a pigment luminance method(PLM) which was calibrated with a fiber-optic liquid film sensor. By means of this technique, we distinguished three different types of interfacial waves, i.e. the ripple wave, the ring wave and the disturbance wave. Furthermore we measured the characteristics of these three different kinds of waves, and in particular those of the disturbance wave: i.e. its propagation velocity, its frequency in passing and the distance between two adjacent waves, and then obtained the dependency of these characteristics on the air and water volumetric fluxes j_g and j_l. These results agreed well with the results obtained by other investigators, using an electric needle contact method. A probable mechanism of the occurrence of the ring and the disturbance waves was posited.