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A study on asymmetric integrated optical Y-branches proposes the use of single-mode asymmetric Y-branches using microprisms to enhance their performance as compared to conventional single-mode asymmetric Y-branches. The configuration of the suggested asymmetric Y-branch, 3-dB power divider is presented. Applications of asymmetric Y-branches in integrated optical circuits will be of great interest in the near future. Experimental results are presented.

A useful design rule for the low-index prism structure was obtained by the concept of phase matching. The designed low-index prism bends were observed to have low-loss and large-angle properties similar to high-index prism bends. Field distortion caused by the prism is discussed as well as the influences of prism length, width and index on the propagation loss. A comparison of the field distribution and design rule of the high-and low-index prism bends was performed.

An improved multigrid technique for the quasi-TEM analysis of a microstrip line embedded in an inhomogeneous anisotropic dielectric medium is presented. A general finite-difference form for the inhomogeneous anisotropic medium is derived by the finite-volume discretization of Gauss' theorem. By the analogy between the quasi-TEM and the steady current problems, this general form can be interpreted by Kirchhoff's current law. Then, the electric potential distribution in this complicated dielectric structure can be regarded as that on a resistive network, which makes the formulation easier. The resulting matrix equation for the potential distribution on the finest grid is solved by the improved multigrid iteration, where the coarse-grid operator is derived directly from the finest grid operator by the help of an equivalent resistive network. Three numerical examples show that the convergence rate is hardly dependent of the number of unknowns and the complexity of the dielectric media. Moreover, the numerical results are in good agreement with those by the other method when special cases are considered. Index Terms - Microstrip, multigrid, quasi-TEM.

The use of micro-prisms to improve the design of three-dimensional bends of step-index waveguides is considered. The approach, which applies to both embedded and buried waveguides, includes a micro-prism design rule to address phase mismatch which leads to bending loss. According to a simulation carried out by the finite-difference beam propagation method, the improved bends achieve dramatic gains in their transmission capabilities.

A newly developed large-angle low-loss direction-coupler type power divider has a designed ratio between output waveguides and employs a micro-prism at the bend corner to restrict radiation loss, compensating for phase mismatch due to bending. The semivectorial beam propagation method simulates a 93% normalized transmitted power of the power divider with a bend angle of 10 degrees. Less than 0.953 dB loss is calculated for a symmetric large-angle 3-dB directional coupler with eight microprisms.

A new low-loss abrupt bend structure for optical waveguide utilizes a microprism to compensate for the phase front phase difference after and before the bend corner. The compensation helps align the phase front of the eigenmode properly. Simulations indicate a 95% normalized transmitter power at 10 degrees of bend angle. A phase compensation rule and its corrections help derive the optical parameters of the prism.

This paper studies the transient behaviors of solitary waves in a relativistic plasma with nonisothermal electrons. In particular, the modified Korteweg-de Vries (K-dV) equation is solved numerically with a Gaussian function as the initial condition. In addition, it is found that the time evolution of solitons from the initial profile is quite similar to that of a K-dV equation with the exception that the soliton speeds are faster. It is also found that the relativistic ions and the nonisothermal electrons tend to have a similar effect on the soliton behavior of the wave, with the effect of nonisothermal electrons being more noticeable.

Analyzes the fabrication of the single and multiple aluminum-gallium arsenide quantum-well structures using liquid-phase epitaxy. Details on the experiments; Results of the study; Conclusions.

Presents a study which examined a hysteresis phenomena of metal-tantalum-oxide-silicon-oxide-silicon capacitors due to leakage current through tantalum oxide. Observation on the C-V behavior of the capacitor; Effects of the direct current and alternating current (ac) resistances of tantalum oxide; Importance of the measurement conditions and the effect of the ac resistance of tantalum oxide on the determination of flat-band capacitance.

Compact lithium niobate polarization-independent electrooptic modulators using integration of polarization splitters and mode converters are presented. Experimental results show polarization-dependent loss as low as 0.04 dB can be achieved for devices fabricated on Z-cut substrates with an applied voltage of 26 V. The electrode lengths required for electrooptic modulation are 10 and 6 mm for TE and TM modes, respectively, and the total device length is only 1.6 cm. Moreover, only one diffusion step is required that greatly simplifies the fabrication process. [ABSTRACT FROM PUBLISHER]

A 45-year-old woman complaining of abdominal fullness was referred for endoscopic examination. She was a non-smoker and non-drinker. An endoscopic examination revealed the presence of more than 100 tiny, rounded, elevated, yellowish lesions <0.5 mm in diameter scattered throughout the upper and lower esophagus. Based on the endoscopic examination results, her stomach manifested symptoms of mildly superficial gastritis. Histopathologic examination of the esophagus biopsy specimen revealed that some of the lobules of the cells displayed typical sebaceous differentiation covered by a squamous epithelium. No evidence of inflammatory reaction, hair follicles, or malignancy was found. The patient's blood and serum findings were unremarkable. Our final diagnosis was multiple tiny ectopic sebaceous glands in the esophagus. This is an interesting and rare case of esophageal sebaceous glands distributed throughout the entire esophagus. Because there were no esophageal symptoms or/and eating problems, the patient did not require endoscopic surgery or other treatment. Follow-up examinations were recommended at intervals between 6 months and 1 year. At the 2-year follow-up, an endoscopic examination revealed no change in the size or the number of the tiny ectopic esophageal sebaceous glands. [ABSTRACT FROM AUTHOR]

Background: Several lines of in vitro and in vivo studies have demonstrated that interleukin-18 (IL-18) shows both antiallergic and allergy-promoting activities. But its expression in allergic diseases remains unknown. Methods: Serum IL-18 levels from atopic dermatitis (AD) model mice, NC/Nga and control mice and from patients with AD and healthy volunteers were measured by ELISA. The relationship between IL-18 levels and serum IgE levels or clinical severity was also examined. Results: Serum IL-18 levels from NC/Nga mice were significantly increased compared to those from control mice. The elevation of IL-18 in the sera was observed prior to the onset and during the development of dermatitis in NC/Nga mice. In addition, IL-18 levels in the sera from patients with AD were significantly (p < 0.05) elevated compared to those from healthy volunteers. However, serum IL-18 levels tended to correlate negatively with serum IgE levels in patients with AD and NC/Nga mice. Conclusion: IL-18 is overexpressed in AD.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Polarization splitters with zinc–nickel and gallium indiffusion optical waveguides fabricated on Z-cut lithium niobate substrates are presented. The device fabrication process needs only one diffusion step and, therefore, is greatly simplified. Experimental results show that, at 1.55- \mu \textm wavelength, the extinction ratios for the TE and TM modes are 27.8 and 24.5 dB, respectively. [ABSTRACT FROM PUBLISHER]

Optical waveguides fabricated by nickel indiffusion on lithium niobate are reviewed. In particular, the fabrication process, index change versus concentration, wavelength dispersion, process-dependent polarization, propagation loss, and electro-optic modulation of the nickel indiffusion waveguide are discussed. To improve the confinement of single-ordinary polarization waveguide fabricated by nickel indiffusion, a novel waveguide made by zinc and nickel indiffusion is presented for the first time. Though the measured propagation loss of the waveguide is larger, the measured output power contours are found more symmetric. Moreover, several TE-TM mode splitters using one or more nickel indiffusion waveguides for the complete mode sorting effect are discussed. [ABSTRACT FROM AUTHOR]

The renal resistive index (RI) value of 0.73 has been proposed as the upper limit in normal adult dogs. In humans, changes in RI with age are associated with plasma renin activity. There are relatively few equivalent reference data for dogs. We obtained reference RI data from 22 clinically healthy dogs <4 months of age and 33 healthy dogs between 4 months and 7 years of age. An association between the RI and plasma renin activity was investigated. The mean RI in the older dogs was 0.65 ± 0.05 vs. 0.75 ± 0.05 in dogs <4 months of age. The mean plasma renin activity in the older dogs was 1.18 ± 1.03 vs. 4.23 ± 3.09 ng/ml/h in dogs <4 months of age. There was a weak linear relationship between the RI and plasma renin activity ( r2=0.280, P<0.01) in dogs <4 months of age. Also in these younger dogs, RI was negatively correlated with age ( r2=0.682, P<0.01). The RI was higher in dogs <4 months of age than in older dogs. Therefore, the mean renal RI is slightly higher in young dogs than reported for an older population and interpretation of the RI must include an assessment of patient age. [ABSTRACT FROM AUTHOR]

Optical waveguides fabricated by gamma-ray irradiation on polymer through a gold mask are presented. The gamma-ray induced index change is found almost linearly dependent on the dose of the irradiation. And the measured propagation losses are low enough for practical application. Due to the high penetrability of gamma ray, uniform refractive index change in depth can be easily achieved. Moreover, due to large-area printing, the uniformity of waveguide made by gamma-ray irradiation is much better than that by e-beam direct writing. [ABSTRACT FROM AUTHOR]

The authors present two-dimensional reconstruction of the refractive index profile of an optical waveguide by using differential near-field optical microscopy. Using an inverse algorithm, the refractive index distribution is obtained directly from the measured optical near-field and its derivatives without any assumption of the index profile. The proposed method also takes advantage of subwavelength resolution and low noises in the waveguide region. Two-dimensional index profile reconstruction of a single mode fiber is measured for the demonstration. The measured optical field distribution and refractive index profile agree quite well with the calculated mode and the known index profile. [ABSTRACT FROM AUTHOR]

Optical waveguides based on benzocyclobutene polymer are fabricated by electron-beam direct writing without etching. The propagation losses of waveguide measured at 1.55 μm for both TE and TM polarizations are 0.76 and 0.86 dB/cm, respectively. Moreover, the characteristics of waveguide bends are discussed for comparison. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 208–210, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20254 [ABSTRACT FROM AUTHOR]

Hemagglutinating proteins (HAPs) were purified from Poker-chip Venus (Meretrix lusoria) and Corbicula clam (Corbicula fluminea) using gel-filtration chromatography on a Sephacryl S-300 column. The molecular weights of the HAPs obtained from Poker-chip Venus and Corbicula clam were 358 kDa and 380 kDa, respectively. Purified HAP from Poker-chip Venus yielded two subunits with molecular weights of 26 kDa and 29 kDa. However, only one HAP subunit was purified from Corbicula clam, and its molecular weight was 32 kDa. The two Poker-chip Venus HAPs possessed hemagglutinating ability (HAA) for erythrocytes of some vertebrate animal species, especially tilapia. Moreover, HAA of the HAP purified from Poker-chip Venus was higher than that of the HAP of Corbicula clam. Furthermore, Poker-chip Venus HAPs possessed better HAA at a pH higher than 7.0. When the temperature was at 4°C-10°C or the salinity was less than 0.5‰, the two Poker-chip Venus HAPs possessed better HAA compared with that of Corbicula clam. [ABSTRACT FROM AUTHOR]

A novel variable transverse-electric and transverse-magnetic (TE–TM) mode splitter using nickel diffusion and annealed proton-exchange waveguides for the TE and TM branches of the splitter is presented. Due to the single-polarization property of the annealed proton-exchange waveguide, the measured polarization extinction ratio for the TE mode is higher than that reported. The measured polarization extinction ratio for the TM mode is as good as that reported, yet the fabrication process of single nickel diffusion is much simpler than that of double zinc-and-nickel diffusions. Moreover, the tunabilities of both TE and TM modes are found to be higher than those reported. [ABSTRACT FROM AUTHOR]