Visualization of deuterium flux and grain boundary diffusion in duplex stainless steel and Fe–30 % Ni alloy,using secondary ion mass spectrometry equipped with a Ga focused ion beam

Time of flight secondary ion mass spectrometry (TOF-SIMS) equipped with a high spatial resolution Ga focused ion beam (Ga-FIB) was applied to understand hydrogen diffusion and desorption behavior in duplex stainless steel and Fe–30 % Ni alloys. Deuterium was used as a tracer of hydrogen. Results showed that the secondary ion intensity from body-centered cubic (bcc) and face-centered cubic (fcc) Fe represents the flux of deuterium from the surface and the concentration of deuterium, respectively. The deuterium-depleted zone can be visualized from the interface between bcc and fcc phase to fcc Fe on the surface. Furthermore, direct visualization of the grain boundary diffusion of deuterium is also possible in fcc Fe–30 % Ni alloys, using Ga-FIB-TOF-SIMS.     

Development of medium and small sized reactors: DMS

Nuclear power is expected to become the main source for electric power generation in Japan for the reasons of energy security and prevention of CO₂ emission. In addition, the slowdown of recent electric power demand and the liberalization of the electric power market are accelerating medium and small sized reactor development. (Hida and Ito, 2003) Furthermore, the needs of medium and small sized reactors have become greater in foreign countries where electric grid systems are weak. Under these circumstances, Hitachi has developed DMS's (Double MS: Modular Simplified & Medium Small Reactors) as 400 MWe class LWR's supported by The Japan Atomic Power Company. (Moriya et al., 2003) In addition, DMS's have been designed based on proven technology that requires no large-scale development, and can therefore be introduced in the market in near future.     

Survival and prognostic factors associated with metastatic nonseminomatous testicular and extragonadal germ cell tumors

To assess prognostic factors in patients with metastatic nonseminomatous germ cell tumors, 50 patients with testicular germ cell tumors (TGCT) and 10 patients with extragonadal germ cell tumors (EGGCT) were studied. The clinical staging system for testicular tumors proposed by The Japanese Urological Association and The Japanese Pathological Society was applied. All patients with EGGCT had primary sites in the retroperitoneum. The 3-year survival rates of TGCT and EGGCT were 71.9% and 60.0%, respectively, and there were no differences in patient characteristics. Patients had significantly worse survival rates if the following applied: choriocarcinoma in the primary tumors, serum lactate dehydrogenase level greater than twice the upper limit of normal, liver, brain, or mediastinal metastases, or retroperitoneal tumors greater than 10 cm. It was concluded that the poor-risk group could be defined as those patients having lymph nodal disease only (stage II or III A) with retroperitoneal tumors greater than 10 cm, having pulmonary disease (stage III B) with retroperitoneal tumors greater than 5 cm, or liver, bone or brain metastases (stage III C), and these criteria will predict the prognosis for patients with advanced disease because the good-risk patients (53% of all patients) and poor-risk patients (47%) in this study had 3-year survival rates of 88.7% and 49.7% (p < 0.0001), and complete response rates of 96.9% and 60.7% (p < 0.005), respectively.     

Temperature stability of ultrahigh-speed GaAs JFET ICs

Ultrahigh-speed digital integrated circuits (ICs) implemented with GaAs/int JFETs are confirmed to be reliable in a wide variety of temperatures. Divide-by-256/258 dual-modulus prescaler ICs using source-coupled FET logic (SCFL) circuits that can operate up to 9 GHz have temperature coefficients of operating frequency stability and input power sensitivity of -17.2 MHz/degree and +0.12 dBm/degree between -20 and +100°C, respectively. Direct-coupled FET logic (DCFL) circuits were also confirmed to have very small temperature coefficients. The variations of the maximum operating frequency and the input power sensitivity of the DCFL divide-by-4 divider IC are -1.93 MHz/degree and +0.47 dBm/degree, respectively, between -60 and +100°C. The variation in the threshold voltage of the JFET is -0.88 mV/degree which is very small for the temperature stability of GaAs digital ICs     

Glycosaminoglycan and collagen distribution in the developing human vitreous

BACKGROUND: We determined the distribution of glycosaminoglycans and collagens in the developing human vitreous. METHODS: Eighty human eyes from 5 gestational weeks to 2 postnatal years of age were used. Glycosaminoglycan components were determined by enzyme digestion with hyaluronidase or chondroitinase AC and ABC and immunohistochemistry for chondroitin, chondroitin-4-sulfate, chondroitin-6-sulfate, and dermatan sulfate. Collagen distribution was determined by immunohistochemistry for types I, II, and III collagens. RESULTS: Enzyme digestion showed that throughout development hyaluronic acid is the main glycosaminoglycan in the vitreous and in the extraocular space at 5-7 gestational weeks. Both areas were filled with mesenchymal cells. Immunohistochemistry showed chondroitin-6-sulfate in the vitreous between 6 and 40 gestational weeks, and chondroitin-4-sulfate between 12 and 40 gestational weeks. Hyaluronic acid and chondroitin sulfate appeared in the retina and around the hyaloid vessels at 12-40 weeks. Immunohistochemistry showed type III collagen in the vitreous and around the mesenchymal cells at 5-7 weeks that was replaced by type II collagen after 8 weeks. CONCLUSIONS: Hyaluronic acid is the major glycosaminoglycan in the vitreous throughout development, except for the transient appearance of chondroitin sulfate at 6-40 gestational weeks. Type III is the main collagen in the early developing vitreous that converts to type II collagen at 8 weeks. The primary and secondary vitreous has the same components as these macromolecules. These vitreous glycosamino-glycans and collagens seem to be produced by mesenchymal cells at an early stage and by the retina and hyaloid vessels during middle and late development.     

An accurate HJFET capacitance-voltage model for implementation witha circuit simulator

We present a new accurate HJFET capacitance model to implement with a circuit simulator. This is an analytical model that describes capacitance-voltage (C-V) characteristics over a wide supply voltage range. The model for a capacitance component due to two-dimensional electron gas (2-DEG) conduction is based on gradual channel approximation, and takes into account the gradual capacitance transition near the threshold voltage. It also takes into account the field dependence of the 2-DEG mobility, which is very strong for deep sub-micron devices. The model for parasitic MESFET capacitance is based on the formula for a Schottky diode. Since the model consists of physical parameters, it provides feedback between the fabrication process and circuit design. The simulated results agree well with the measurements     

Polymer waveguide thermooptic switch with low electric powerconsumption at 1.3 μm

A polymer waveguide thermooptic 2×2 switch with low electric power consumption is demonstrated. The switch consists of a Mach-Zehnder interferometer with Cr thin-film heaters. The waveguides are fabricated using acrylic polymers synthesized from deuterated methacrylate and deuterated fluoromethacrylate monomers. The total insertion loss of the switch is 0.6 dB at a wavelength of 1.3 μm, including fiber coupling losses and waveguide losses. The switching power is as low as 4.8 mW, and the rise and fall times are both 9 ms     

10GHz GaAs JFET dual-modulus prescalar IC

A divide-by-256/258 dual-modulus prescalar IC has been successfully fabricated using enhancement-mode GaAs JFETs. The maximum operation frequency of 10.4 GHz is obtained by a 0.5 mu m gate length and buried p-layer JFET technology. The prescalar IC has sufficient operational margin to make it compatible with Si bipolar ECL circuits over a wide frequency range.<>     

Spontaneous shrinkage of lumbosacral lipoma in conjunction with a general decrease in body fat: case report

OBJECTIVE AND IMPORTANCE: We describe a rare case of a lumbosacral lipoma that shrank spontaneously in parallel to a general loss of body fat. Although early prophylactic surgery is generally recommended for lumbosacral lipomas, the observation made in this case may provide an important implication regarding the conservative management of this disorder. CLINICAL PRESENTATION: A 9-year-old male patient with a subcutaneous lipoma at the sacral level was found to have a lumbosacral lipoma in the spinal canal and tethered spinal cord, as revealed by magnetic resonance imaging. The patient showed no neurological or urological deficits, except for a mild pes cavus deformity. INTERVENTION: Follow-up magnetic resonance imaging performed 4 years later revealed a significant decrease in the size of the lumbosacral lipoma. The patient became very thin and showed no neurological deterioration during the follow-up period. The shrinkage of the lipoma was considered to be in association with the general loss of body fat. CONCLUSION: The control of body weight may be an important factor in the conservative management of patients with lumbosacral spinal lipomas.