Polarization sensitivity of a silica waveguide thermooptic phaseshifter for planar lightwave circuits

A thermooptic (TO) phase shifter, which consists of a thin-film heater loaded on a silica-based single-mode waveguide on a Si substrate, was found to exhibit a sli1h,t polarization dependence of about 3.1% between the TE and TM modes. This dependence, which is caused by anisotropic stress concentration due to local heating, was successfully reduced by forming stress-releasing grooves on either side of the heater     

Mechanochemical synthesis of indium complex oxides (InAO4; A = P, V, Nb, Ta, Sb) and their solid solutions

Indium complex oxides, InAO₄ (A = P, V, Nb, Ta, Sb), were synthesized by milling of the In₂O₃ and A ₂O₅ mixture using planetary ball mill at room temperature. Formation of these compounds was monitored by powder X-ray diffraction (XRD) and was found to be complete with 240 or 480 min. This method has been successfully extended to the synthesis of solid solutions, InP_1−x V _x O₄ and InTa_1−x Nb _x O₄, between these indium complex oxides.     

Microlens arrays for integral imaging system

When designing a system capable of capturing and displaying 3D moving images in real time by the integral imaging (II) method, one challenge is to eliminate pseudoscopic images. To overcome this problem, we propose a simple system with an array of three convex lenses. First, the lateral magnification of the elemental optics and the expansion of an elemental image is described by geometrical optics, confirming that the elemental optics satisfies the conditions under which pseudoscopic images can be avoided. In using the II method, adjacent elemental images must not overlap, a condition also satisfied by the proposed optical system. Next, an experiment carried out to acquire and display 3D images is described. The real-time system we have constructed comprises an elemental optics array with 54 H x 59 V elements, a CCD camera to capture a group of elemental images created by the lens array, and a liquid crystal panel to display these images. The results of the experiment confirm that the system produces orthoscopic images in real time, and thus is effective for real-time application of the II method.     

Depression and the risk of coronary heart disease in the Normative Aging Study

BACKGROUND: Epstein-Barr virus (EBV) infection is common after liver transplantation in children and is associated with the risk of posttransplant lymphoproliferative disorders (PTLD). METHODS: This retrospective study examined the frequency of gastrointestinal (GI) symptoms and the risk of PTLD in pediatric liver recipients who developed symptomatic EBV infection. We reviewed 172 children who received orthotopic liver transplants between March 1988 to December 1994. Twenty-two cases were retransplants. The mean age at transplantation was 3.7 years (range, 0.1-17 years). The immunosuppressive regimens consisted of induction therapy with Minnesota antilymphocyte globulin/antithymocyte globulin/OKT3 in most cases and maintenance therapy with prednisone and either cyclosporine or tacrolimus (FK506). RESULTS: After 1 year of minimum follow-up, 54 of 172 patients had symptomatic EBV infections (confirmed by serology, histology, or whole blood polymerase chain reaction. At the time of infection, 38.5% (21/54) had either diarrhea or GI bleeding or both. PTLD developed in 11 patients (6.4%). The incidence of PTLD was 42.9% (9/21) when GI bleeding or diarrhea was associated with EBV infections, compared with 6.1% (2/33) when EBV infection was not associated with GI symptoms. Seven of 10 (70%) patients with GI bleeding and 2 of 11 (18.2%) with diarrhea developed PTLD. Of seven patients examined by endoscopy for GI bleeding, two had biopsy-proven PTLD of the GI tract, whereas one of two patients examined by endoscopy for diarrhea had biopsy-proven PTLD. DISCUSSION: In summary, a high incidence of PTLD was found in patients who developed GI bleeding or diarrhea associated with EBV infection after pediatric liver transplantation. In these patients, endoscopy and biopsy may lead to early diagnosis of PTLD.     

Polyenylidene thiazolidinedione derivatives with retinoidal activities

Several polyenylidene thiazolidine or 2-thioxo-4-thiazolidinone derivatives were synthesized and their retinoidal activities were examined in terms of the differentiation-inducing ability towards human promyelocytic leukemia HL-60 cells and inhibitory effect on interleukin (IL)-1 alpha-induced IL-6 production in MC3T3-E1 cells. Compounds containing a trimethylcyclohexenyl ring induced HL-60 cell differentiation with weaker activity than retinoic acid (1a) by one or two orders of magnitude. The thiazolidinedione derivatives (2, 5, 7) showed stronger activity than the corresponding 2-thioxo-4-thiazolidinone derivatives (3, 6, 8). The effects of a retinoid antagonist (LE540) and synergists (retinoid X receptor (RXR) agonists, HX600 or HX630) on the activities of thiazolidine derivatives indicate that these compounds elicit their activities through the nuclear retinoic acid receptors (RARs). All the thiazolidines examined also inhibited IL-1 alpha-induced IL-6 production with IC50 values of 10 nM order. The retinoidal activities of the thiazolidines are significant, considering that replacement of the carboxylic acid in retinoid structures with bioisosteric functional groups is generally ineffective, as seen in the structure-activity relationships of retinoidal benzoic acids.     

Duodenum-preserving resection of the pancreatic head for mucinous ductal ectasia without overt carcinoma

BACKGROUND/AIMS: The clinical characteristics of mucinous ductal ectasia (MDE) of the pancreas without overt carcinoma have not been clarified. To clarify MDE and assess the optimal treatment procedure, including the technique of duodenum-preserving resection of the pancreatic head (DpRPH), we studied four patients. METHODOLOGY: Our patients consisted of three men and one woman, with a mean age of 71 years. The patients underwent DpRPH (n=3) or the pylorus-preserving Whipple procedure (PpW) (n=1). Clinicopathological features, postoperative pancreatic function, and technique to preserve duodenal blood flow were studied. RESULTS: All patients had intraductal mucin-hypersecretion and multilocular cysts lined by hyperplastic epithelium. The lesions were located in the uncinate process (n=3) or head-body (n=1) of the pancreas. DpRPH totally removed the lesions in the uncinate process. Of the three patients receiving DpRPH, dusky duodenum and a postoperative duodenal ulcer developed in two whose gastroduodenal arteries (GDA) were divided, but did not develop in one with undivided GDA. Postoperative glucose tolerance test and peptide para-aminobenzoic acid test after DpRPH showed better values than those after PpW. All patients are alive and well 22 to 40 months after surgery. CONCLUSIONS: DpRPH is a new standard for MDE. During DpRPH, preservation of the GDA and the superior portion of the pancreatic head is recommended to maintain an adequate duodenal blood flow.     

Loss Probability for a Finite Buffer Multiplexer with the <Emphasis Type="Italic">M/G/∞</Emphasis> Input Process

This paper studies the impact of long-range-dependent (LRD) traffic on the performance of a network multiplexer. The network multiplexer is characterized by a multiplexing queue with a finite buffer and an M/G/∞ input process. Our analysis expresses the loss probability bounds using a simple relationship between loss probability and buffer full probability. Our analysis also derives an exact expression for the buffer full probability and consequently calculates the loss probability bounds with excellent precision. Through numerical calculations and simulation examples, we show that existing asymptotic analyses lack the precision for calculating the loss probability over realistic ranges of buffer capacity values. We also show that existing asymptotic analyses may significantly overestimate the loss probability and that designing networks using our analysis achieves efficient resource utilization.     

2 × 2 optical waveguide matrix switch using nematic liquid crystal

A 2 × 2 nonblocking optical matrix switch, composed of four elemental switches formed in a slab waveguide, is described. Switching action is based on total internal reflection caused by an electrically controlled change in refractive index of the liquid crystal. Propagation loss was remarkably reduced to 2.3 dB/cm, both by using liquid crystal as a cladding layer and by operating at the 1.31 μm wavelength. The experimental matrix switch exhibited 7.3-7.7 dB insertion loss, -17.3 to -18.2 dB crosstalk, and a 14° switching angle.     

Enzyme electrode based on gold-plated polyester cloth

Summary Glucose oxidase is immobilized on gold-plated polyester cloth by entrapment method and coupled with an electron mediator, ferrocene derivative. Cyclic voltammogram depends on the existence of the substrate glucose and the flavo-enzyme was shown to donate electron(s) to the cloth electrode with mediation of the ferrocene derivative even in the immobilized state. The glucose-concentration dependence of the peak current was linear upto several tens of 35 mM, depending on the concentration of the mediator. Co-immobilization of polymer-anchored electron mediator is also studied.     

Design and fabrication of silica-based integrated-optic 1*128 power splitter

A 1*128 optical power splitter is fabricated by integrating 127 Y-branch waveguide elements on a 3 inch silicon wafer using silica waveguide technology. The average measured excess loss of this splitter is 3.2 dB including fibre-waveguide coupling loss.<>