Simple and rapid method for determining nicotinamide adenine dinucleotide synthetase activity by high-performance liquid chromatography

A method is described for the determination of nicotinamide adenine dinucleotide synthetase (NADS) activity in human blood. Using high-performance liquid chromatography (HPLC), the formed NAD is separated from the substrates and the other blood components in less than 13 min. The activity of NADS determined by HPLC is closely correlated with that determined by the conventional spectrophotometric method, which requires two steps of enzyme reaction. The present method is simple and reliable and facilitates the routine analysis of NADS activity.     

A 20-ps Si bipolar IC using advanced super self-aligned processtechnology with collector ion implantation

A super self-aligned process technology, SST-1B, which is an advanced version of the previously proposed SST-1A in high-speed Si bipolar LSIs is discussed. A selectively ion-implanted collector (SIC) process and bird's-beak-free isolation process are utilized. The SIC process is designed to improve shallow base-collector profiles in the intrinsic region. It reduces base width and intrinsic base resistance, and suppresses the base push-out effect (Kirk's effect) in high-current operations. The SIC profile is easily controlled by 150-200 keV phosphorous ion implantation at the base-collector junction. Using these processes, SST-1B has achieved a high cutoff frequency of 21.1 to 25.7 GHz and a fast switching delay of 20.5 ps/G for nonthreshold logic and 34.1 ps/G for emitter-coupled logic. SST-1B has potential applications to 50-ps/G logic LSIs and 10-GHz SSIs. Device simulation indicates that it is possible to achieve a cutoff frequency of 40-50 GHz in a future scaled-down Si bipolar transistor with a 40-nm base and graded collector     

Effects of oxidizing gases on semiconductivity and thermal stability of phthalocyanine thin films

The effects of oxidizing gases (O₂ and NO₂) on the p-type semiconductivity of the phthalocyanines H₂Pc, PbPc, ZnPc, CuPc, AlPcCl, AlPc-O-AlPc and (AlPc) _n films treated in nitrogen at 350 ° C have been examined. The conductance increased in the presence of oxidizing gases. Reversible effects of oxidizing gases on the conductance were observed for PbPc, CuPc and ZnPc, all of which are thermally and/or chemically less stable than the other Pcs. For the latter, the conductance in nitrogen increased permanently after exposure to NO₂. The reversibility of the former may be related to the thermal and chemical stability of neutral and/or oxidized phthalocyanines. The conductivity is described byG =G ₀ exp (E/kT) The activation energy,E, decreased in the presence of oxidizing gases. The pre-exponential factor,G ₀, was lowered by the introduction of NO₂ especially for PbPc, CuPc and ZnPc. It seems that the adsorption of NO₂ is limited to the surface of fine crystals and the increase in the conductance caused by exposure to NO₂ is strongly influenced by the crystallinity of phthalocyanine.     

99Tcm-MAG3: a sensitive indicator for evaluating perfusion and rejection of renal transplants

Radionuclide renography has a role in evaluating perfusion of transplanted kidneys. In the course of rejection, cortical perfusion decreases before urinary excretion changes. Based on the facts that 99Tcm-MAG3 has different pharmacokinetics and shows a higher kidney-to-background count ratio than 99Tcm-DTPA, we postulated that 99Tcm-MAG3 was a sensitive and reproducible agent to measure cortical perfusion of transplanted kidneys. To clarify the feasibility of using 99Tcm-MAG3 to measure the cortical perfusion index (CPI), sequential renography was performed using 99Tcm-DTPA and 99Tcm-MAG3 in 14 patients with stable renal transplants, who had changes in serum creatinine concentration of less than 50% between the two studies. The CPI was calculated with 99Tcm-DTPA and 99Tcm-MAG3 and these were then compared and correlated with concurrent serum creatinine concentration. The CPI with 99Tcm-MAG3 was 1.43 times that with 99Tcm-DTPA in patients with changes in serum creatinine concentration equal to or less than 20%, and regression analysis revealed that the difference in CPI was larger in patients with more severely decreased renal perfusion than in patients with normal or mildly decreased renal perfusion. This preliminary study has indicated that the CPI with 99Tcm-MAG3 is a sensitive index for detecting changes in renal function, and thus is a feasible indicator of cortical perfusion when evaluating the rejection of transplanted kidneys.     

A concentrator module of spherical Si solar cell

Spherical Si solar cell, which is made up of Si spheres with a diameter of approximately 1.0 mm, is expected to be a promising candidate for low consumption of Si feedstock and simple process technology. This paper describes the formation process and the structure of a concentrator module in detail. The concentrator lens was formed by casting with ultraviolet light hardening resin. The concentration ratio was 4.4 times and the pitch between the spheres was 2.0 mm. By this module design, it was possible to realize a consumption of the Si feedstock of about 3.0 g/W. Conversion efficiencies of 11.3% from single-sphere cell, 8.5% from a 23-spheres module and 5.2% from a 105-spheres module under AM1.5, 100 mW/cm² illumination were achieved.     

Lasing band-edge identification for a surface-emitting photonic crystal laser

The possibility of single-mode oscillation over a large cavity area for photonic crystal lasers emitting at the photonic band edge has resulted in much interest in such materials for new forms of solid-state laser. In this paper, we measure the photonic bandstructure in our sample and identify the lasing band edge. By mapping out the bandstructure at the /spl Gamma/-point, we have observed fine structure at the band edge. The experimental results are in good agreement with the theoretically predicted bandstructure. Above threshold, we observe a lasing peak at 965 nm at one of the band edges. The far-field distribution of the laser is measured, showing an annular profile and azimuthal polarization. Calculations on the far-field distribution at the lasing band edge suggest the annular profile is due to an anti-symmetric resonant mode.     

Interfacial phenomena in the liquid copper-calcium ferrite slag system

The surface and interfacial tensions of the copper-calcium ferrite slag system were determined at 1573 K as a function of oxygen and sulfur pressures and CaO content in the slag. The effect of a 2.9 mass pct SiO₂ addition to the calcium ferrite slag was also investigated. The measurements were carried out using the sessile drop technique with a high-temperature X-ray setup. The surface tension of copper was found to be a strong function of oxygen and sulfur partial pressures. The surface tension of the calcium ferrite slag decreased slightly with CaO addition. On the other hand, CaO had a negligible effect on the interfacial tension of the system. Surface tension of the slag and the interfacial tension were influenced by the oxygen partial pressure in the system. Sulfur partial pressure also altered the interfacial tension between the copper and the ferrite slag. Based on the experimental data, filming and flotation coefficients were calculated to predict the entrainment behavior of copper, by bubble attachment in the ferrite slag.     

Effect of molecular weight distribution of mineral oils on their boiling heat transfer behaviour

The range of molecular weight distribution of mineral oils has a significant effect on lubrication because it affects the thermal behaviour of the mineral oils.In view of the fact that boiling heat transfer is one of the most typical problems relevant to thermal phenomena, an investigation of boiling heat transfer from a horizontal platinum wire to mineral oils was carried out using (i) base oils characterized by narrow-range molecular weight distributions and (ii) blended oils characterized by wide-range distributions.The objective of the present study is to clarify the relationship between the range of molecular weight distribution and the boiling heat transfer behaviour of such oils.The results obtained show marked differences between base and blended oils in their boiling heat transfer behaviour, especially with respect to the heat transfer coefficients.An explanation of these differences was attempted in terms of correlation with the results of the present authors' previous investigations of the evaporation and spreading behaviour of droplets of these oils on a horizontal heating surface, both of which showed the essential differences between the base and blended oils in the heat and mass transfer properties.