1330 V, 67 m/spl Omega//spl middot/cm/sup 2/ 4H-SiC(0001) RESURF MOSFET

Design and fabrication of 4H-SiC(0001) lateral MOSFETs with a two-zone reduced surface field structure have been investigated. The dose dependencies of experimental breakdown voltage show good agreement with simulation. Through the optimization of implant dose, high-temperature (1700/spl deg/C) annealing after ion implantation, and reduction of channel length, a breakdown voltage of 1330 V and a low on-resistance of 67 m/spl Omega//spl middot/cm/sup 2/ have been obtained. The figure-of-merit (V/sub B//sup 2//R/sub on/) of the present device reaches 26 MW/cm/sup 2/, being the best performance among lateral MOSFETs reported. The temperature dependence of static characteristics is also presented.     

Allogeneic peripheral blood stem cell transplantation in 30 patients with hematologic disorders

Thirty patients (median age of 32 years; range, 6-61) with hematologic disorders received unmanipulated peripheral blood stem cell transplants from HLA-matched or one-antigen-mismatched related donors following myeloablative therapy for acute lymphoblastic leukemia (7), acute myelogenous leukemia (6), chronic myelogenous leukemia (8), myelodysplastic syndrome (3), or other disorders (6). Granulocyte colony stimulating factor (G-CSF) mobilized peripheral blood stem cells were collected from donors in 1 to 3 aphereses. The apheresis products contained mean counts of 11.3 x 10(8) (range, 3.8-17.2) nucleated cells/kg and 6.7 x 10(6) (range, 1.3-16.7) CD34+ cells/kg. Graft-versus-host-disease (GVHD) prophylaxis consisted of cyclosporin A plus methotrexate, or FK506 plus methotrexate. All patients received G-CSF following their transplant. Although 1 patient died of pneumonia 6 days after transplantation, the others demonstrated rapid engraftment. Median days to recovery to 500/microliter neutrophils and 20,000/microliter platelets were 13 (range, 8-21) and 14 (range, 1-23) days, respectively. The incidence of acute GVHD grade II-IV was 33%; chronic GVHD developed in 57% of the assessable patients. There were no episodes of graft failure or rejection. Nineteen patients (63%) were alive and in complete remission from 147 to 839 days following their transplant (median follow-up of 560 days). Further follow-up study will be required to assess the incidence of chronic GVHD and graft-versus-leukemia (GVL) effects.     

Evaluation of the PyloriTek test for detection of Helicobacter pylori infection in cases with and without eradication therapy

OBJECTIVE: The accuracy of the PyloriTek test (a 1-h rapid urease test) used after eradication therapy of Helicobacter pylori (H. pylori) has not been well clarified. This study was done to evaluate the accuracy of the PyloriTek test results for cases with and without eradication therapy, using culture and histology as gold standard methods, and to establish the suitable timing of the PyloriTek test after eradication treatment. METHODS: One hundred sixty-three patients undergoing upper endoscopy were randomly selected; 100 patients had not received eradication therapy and 63 had. Three biopsy specimens each were obtained from the gastric antrum and the body for examination by PyloriTek, culture, and histology. The absence of H. pylori was established with negative results from both culture and histology. RESULTS: In cases without eradication therapy, PyloriTek, correctly identified 66 of 67 H. pylori-positive cases and 30 of 33 H. pylori-negative cases, yielding 98.5% sensitivity and 90.9% specificity. In cases with eradication therapy, PyloriTek gave correct diagnoses in 10 of 17 H. pylori-positive cases and in 45 of 46 H. pylori-negative cases, for 58.8% sensitivity and 97.8% specificity. However, when PyloriTek was used more than 4 months after the end of eradication therapy, both the sensitivity and the specificity increased to 100%. CONCLUSION: Considering time and cost, the use of PyloriTek alone may be satisfactory for detecting H. pylori infection in cases without eradication therapy. When patients are examined more than 4 months after intervention, the use of PyloriTek alone may be sufficient for correctly diagnosing H. pylori infections.     

Chronic Beryllium disease after exposure to low-beryllium-content copper

A 24-year-old man was admitted to our hospital because of exertional dyspnea and abnormal shadows on chest X-ray film. He worked in a factory, where he was exposed to 1.8% beryllium-copper alloys. His job was to draw out heated beryllium-copper wire to make it more fine. Chest X-ray film and chest CT scan showed left-sided pneumothorax, diffuse fine reticulonodular shadows, and several cysts. Pulmonary-function tests showed a restrictive disorder and a low diffusing capacity. A specimen obtained by open-lung biopsy showed epithelioid cell granuloma and alveolitis, which were compatible with chronic beryllium disease. The beryllium content of the lung tissue was 0.045 microgram/gram. Beryllium lymphocyte transformation tests on blood and on bronchoalveolar lavage fluid were positive. Based on these findings, chronic beryllium disease was diagnosed. After treatment with 1 mg/kg of prednisolone daily, dyspnea disappeared. Then the dose was tapered slowly. In Japan, chronic beryllium disease is extremely rare, and to our knowledge only 22 other cases have been reported.     

Sulfated glycoconjugates demonstrated in combination with high iron diamine thiocarbohydrazide-silver proteinate and silver acetate physical development.

Sulfated glycoconjugates in epithelial cells and mesenchymal cells were investigated after staining with high iron diamine-thiocarbohydrazide-silver proteinate. One purpose of the experiment was to apply a new physical developed to the staining. Instead of silver nitrate, silver lactate or silver bromide, we used silver acetate as an ion donor. This new method allowed physical development under normal lighting conditions, and resulted in the reduction of background staining even after amplification. As the developer did not contain gum arabic, troublesome treatment was not necessary. The time required for staining was very short and the electron density of the final reaction product was high and easily identifiable under the electron microscope. Fixing was not necessary. Very small amounts of reactive substance were detectable after physical development. This developmental procedure has been applied to both the preembedding staining and postembedding staining of sulfated glycoconjugates. The results obtained using this method are presented.     

Chirping characteristic and frequency response of MQW opticalintensity modulator

The spectral linewidth enhancement factor and frequency responses of electro-absorption-type optical-intensity modulators, especially InGaAs/InAlAs MQW modulators, are described. A method of exactly estimating the value of the α factor is presented under the nonlinearity of extinction-ratio characteristics. For measuring the frequency response of modulators, the sideband strength of the modulated output light with an optical spectrum analyzer, is analytically compared with the microwave power of photodiode direct detection with an electrical spectrum analyzer     

Nonlinear dynamics of offshore structures under sea wave and earthquake forces

A study of dynamic response of offshore structures in random seas to inputs of earthquake ground motions is presented. Emphasis is placed on the evaluation of nonlinear hydrodynamic damping effects due to sea waves for the earthquake response. The structure is discretized using the finite element method. Sea waves are represented by Bretschneider’s power spectrum and the Morison equation defines the wave forcing function. Tajimi-Kanai’s power spectrum is used for the horizontal ground acceleration due to earthquakes. The governing equations of motion are obtained by the substructure method. Response analysis is carried out using the frequency-domain random-vibration approach. It is found that the hydrodynamic damping forces are higher in random seas than in still water and sea waves generally reduce the seismic response of offshore structures. Studies on the first passage probabilities of response indicate that small sea waves enhance the reliability of offshore structures against earthquakes forces.     

Possibility of using near infrared spectroscopy for evaluation of bacterial contamination in shredded cabbage

The possibility of near infrared (NIR) spectroscopy to measure the amount of bacterial contamination in shredded cabbage was investigated. NIR measurements in the short wavelength region from 700 to 1100 nm were done using two types of saline solutions: one was used to stomach with the samples as the conventional method and the other was used to wash the outer surface of the sample to examine the possibility of a non‐destructive method. Partial least squares regression (PLS) was used to develop the equations for bacterial amount. Spectra from the stomacher solution and the washing solution produced similar results. Sufficiently accurate results could be obtained with the bias‐corrected standard error of prediction (SEPs) of 0.46 log CFU g^?1 for the stomacher solution and 0.44 log CFU g^?1 for the washing solution. NIR spectroscopy was clarified to be a rapid and non‐destructive method for prediction of bacterial contamination in shredded cabbage.     

Degradation of organic solar cells due to air exposure

We present a study of dark air-exposure degradation of organic solar cells based on photoactive blends of the conjugated polymer, poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) with [6,6]-phenyl C₆₁-butyric acid methyl ester (PCBM). Photovoltaic devices were fabricated on indium tin oxide (ITO) glass with or without a layer of poly (3,4-ethylenedioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS), and were studied without encapsulation. Photovoltaic performance characteristics were measured as a function of time for different ambient conditions (under white light irradiation and in the dark, and under air, dry oxygen and humid nitrogen atmospheres). It was found that a key cause of degradation under air exposure is light independent and results from water adsorption by the hygroscopic PEDOT:PSS layer. Measurements of the charge mobility and hole injection after air exposure showed that the degradation increases the resistance of the PEDOT:PSS/blend layer interface.