Time shared lightwave reference frequency distribution forphotonics networks

Time shared lightwave reference frequency distribution is demonstrated using a pulsed lightwave sweep frequency generator, tracking generators, and a linear repeater. The reference lightwave, which contains over 1000 frequencies in 250 MHz steps, is generated using a dynamically gain controlled erbium-doped fiber amplifier and acoust-optical deflector. Continuous lightwave frequencies locked to the distributed time shared reference frequency are generated over a 200 GHz range with an instability of only ±5 MHz. Absolute lightwave frequency from the tracking generator is confirmed by a frequency chain between two hydrogen cyanide gas cell stabilized lightwave sources. The effect of fiber nonlinearity encountered in frequency distribution, a dynamically gain stabilized linear repeater, and system design are also discussed     

Selected ion monitoring gas chromatography/mass spectrometry of 1,2-diacylglyceroltert-butyldimethylsilyl ethers derived from glycerophospholipids

Selected ion monitoring was used in conjunction with gas chromatography/mass spectrometry to analyzetert-butyldimethylsilyl ethers (tert-BDMS) of 1,2-diacyl-sn-glycerols derived from naturally occurring glycerophospholipids, including those ofEscherichia coli, soybean, egg yolks and porcine liver. First, the fatty acid composition of the unknown glycerophospholipid was determined by gasliquid chromatography (GLC) and, based on that, the fatty acids (mostly >0.5 wt%) were selected for monitoring the characteristic fragmentation ions produced from the fatty acid residues of the correspondingtert-BDMS derivatives of 1,2-diacyl-sn-glycerols. Next, thetert-BDMS derivatives were separated by GLC on a 65% methylphenylsilicone gum wall-coated open-tubular (WCOT) column according to the degree of unsaturation and the chain length of the fatty acid residues, and then directly introduced into the ion source of the mass spectrometer. The selected fragmentation ions, [RCO+74]⁺ representative of the fatty acid residues, and [M-57]⁺ indicative of the molecular weight of the derivatives, were monitored simultaneously. It thus became possible to determine the molecular species of thetert-BDMS derivatives by measuring a specific combination of two [RCO+74]⁺ and an [M-57]⁺ ion with the same retention time on the selected ion monitoring (SIM) profile. High background noise caused by volatilization of stationary phase at high temperature was largely overcome by selected ion monitoring. However, the fragmentation ion peaks produced fromtert-BDMS derivatives of highly unsaturated glycerophospholipids showed a distorted SIM profile, which was attributed to interaction between thetert-BDMS derivatives and the methylphenylsilicone phase of the column. Use of a WCOT column with a more polar liquid phase is therefore recommended for the analysis of highly unsaturated molecular species.     

Absence of vagina and hypoplasia of the urethra and ectopia of the ureter

This study evaluated the cost of autologous and homologous blood products. The cost effectiveness of the transfusion therapy was not evaluated. To compare the different products, the cost of one gram of transfused haemoglobin was calculated. Acute normovolaemic haemodilution is the most economical technique. Intraoperative autologous transfusion without washing is the most expensive. All blood products from the autologous techniques, except the latter, were less expensive than homologous red cells.     

Influence of the degree of acetylation of o-cresol resin on its molecular conformation in solution

o-Cresol-formaldehyde resin (OC) and five kinds of acetylated OC (AC-X-OC; X is the degree of acetylation) were prepared. The Θ-temperature for each resin was determined by means of the Shultz-Flory method, and their molecular conformations in both tetrahydrofuran (THF) and Θ-solvent were estimated from the values of the exponents in the Mark–Houwink–Sakurada equations. The effect of the degree of acetylation on the exponent was negligible in THF, but was remarkable in Θ-solvent. In THF, the molecular chains of these resins are relatively extended, because the hydrogen bond between phenolic hydroxyl groups is loosely formed. In Θ-solvent, however, the molecular conformation is compact and the resins are considered to form a pseudo cross-linked network structure through inter- and/or intra-molecular hydrogen bonds. The Mark–Houwink–Sakurada equation for AC-100-OC in 2-ethoxyethanol at 92.0°C was found to be [η]_θ = 0.0773 M?^0.50_n, where [η]₀ is the limiting viscosity number under the Θ-condition, and M?_n is the number-average molecular weight. The unperturbed dimension, (〈r²₀〉/M?_n)^1/2, 〈r²₀〉 being the unperturbed mean square end-to-end distance, for AC-100-OC was found to be 0.659×10^?8 cm g^?1/2 mol^1/2.     

Evaluation of early graft function by hepatic venous hemoglobin oxygen saturation following orthotopic liver transplantation in the rat

This study was designed to evaluate the use of hepatic venous oxygen saturation (Shvo2) as a predictor of early graft function after liver transplantation. We examined the levels of Shvo2 and serum ALT after transplantation using the isogeneic rat orthotopic liver transplant model. Shvo2 levels 2 hr after reperfusion in the 6-hr cold ischemia (nonviable allograft) group were significantly lower than those in the 1-hr and 3-hr cold ischemia (viable allograft) groups. However, there was no significant difference in ALT levels among these groups. These results suggest that decreased hepatic blood flow due to microcirculatory disturbances may occur in the nonviable allograft even in the early phase of reperfusion and may be responsible for ischemic damage to parenchymal cells. Therefore, Shvo2 could provide a simple index of the initial graft status and be useful for a rapid etiological diagnosis of early postoperative graft dysfunction and for estimating the graft outcome after liver transplantation.     

Dental gold alloys with age-hardenability at intraoral temperature

Dental gold alloys with age-hardenability at intraoral temperature were developed. Either 3 or 6 at% Ga, Al, Zn, In, Ni or Pd were added to an equiatomic AuCu alloy and the effect of additives on the low-temperature age-hardenability was examined. Alloys containing Ga, Al or Zn exhibited excellent low-temperature age-hardenability. The hardness of an alloy containing 6 at% Ga or 6 at% Al was doubled in one to ten days by ageing at 37 °C. Pronounced hardening was not demonstrated in an as-cast alloy, but solution treatment for only a few minutes provided enough age-hardenability. The age-hardening rate at low temperature related closely with the melting temperature of the alloy. Experimental gold alloys exhibited electrochemical behaviour similar to that of a commercial Type IV gold alloy. It is therefore concluded that AuCu alloy with added Ga, Al or Zn is expected to have enough age-hardenability and corrosion resistance for clinical use in the oral environment.     

The effect of water quality on pitting corrosion of copper tube in hot soft water

Laboratory reproduction of pitting on copper was attempted in a hot, circulating water loop for the purpose of clarifying the mechanism and establishing countermeasures to the pitting. Type 2 pitting was observed to occur on the internal surface of copper tubes after long-time exposure to Tokyo water, when it was heated to 60°C and residual chlorine of 2～3 mg/l was added. After prolonged loop testing, the electrode potential of copper exceeded the critical value, +150 mV(SCE). The pits were deep and acute, and were covered with greenish blue products, which were identified as basic copper sulfate. Pitting did not occur in water free of residual chlorine even under air-saturated conditions, in which copper retained a low potential value.     

Thermal dehydrochlorination of poly(vinyl chloride). I. Effect of iron oxide on the rate of dehydrochlorination

The thermal degradation of poly(vinyl chloride) (PVC) was studied by following the rates of dehydrochlorination at temperatures between 180°C in pure nitrogen and air flow. Iron oxide accelerates the elimination of hydrogen chloride from PVC. The accelerating effect depends on the concentration of the oxide, and it has a maximum. This work tried to explain these behaviors. A mechanism of dehydrochlorination is suggested for polymer containing iron oxide.     

Boundary-integral equation method for elastodynamic scattering by a compact inhomogeneity

The set of singular integral equations which relates unknown fields on the surface of the scatterer to a time-harmonic incident wave is solved by the boundary element method. The general method of solution is discussed in some detail for scattering by an inclusion. Results are presented for a spherical cavity, and for a soft and a stiff spherical inclusion. Fields on the surface of the scatterer are compared with previous results obtained by different methods. Back-scattered and forward-scattered displacement fields are presented, both as a function of position at fixed frequency, and as a function of frequency at fixed position. The quasi-static approximation is briefly discussed.