Design and experimental demonstration of a variable-length optical packet routing system with unified contention resolution

This paper presents theoretical design, network simulation, implementation, and experimental studies of optical packet routing systems supporting variable-length packets. The optical packet switching network exploits unified contention resolution in core routers in three optical domains (wavelength, time, and space) and in edge routers by traffic shaping. The optical router controller and lookup table, implemented in a field-programmable gate array (FPGA), effectively incorporates the contention resolution scheme with pipelined arbitration of asynchronously arriving variable-length packets. In addition, real-time performance monitoring based on the strong correlation between the bit-error rates of the optical label and those of the data payload indicates its application in optical time-to-live detection for loop mitigations. Successful systems integration resulted in experimental demonstration of the all-optical packet switching system with contention resolution for variable-size packets.     

Crystal quality of a 6H-SiC layer grown over macrodefects by liquid-phase epitaxy: a Raman spectroscopic study

Liquid-phase epitaxial (LPE) growth on silicon carbide simultaneously covers macroscale defects, e.g. micropipes, and improves the quality of the crystal. In this study, an epi-layer grown over a macrodefect was evaluated by micro-Raman scattering spectroscopy. Before the growth process, the density of the stacking fault was high and the carrier density spatially inhomogeneous in the vicinity of the macrodefects. On the other hand, after growth, the layer over the macrodefect displayed good quality; the density of the stacking fault was less than that before growth and the homogeneity of the carrier density improved.     

On‐Demand Liquid Transportation Using Bioinspired Omniphobic Lubricated Surfaces Based on Self‐Organized Honeycomb and Pincushion Films

In this work, on‐demand control of liquids is realized by using elastic, patterned omniphobic surfaces. This paves the way for novel microfluidics, as well as liquid harvesting, transportation, and manipulation technologies. Inspired by the lubricating properties of pitcher plants, microstructured 1,2‐polybutadiene honeycomb and pincushion films obtained by self‐organization are fluorinated by the ene‐thiol reaction and infused with fluorinated lubricant to obtain omniphobic liquid‐repellent surfaces. Unlike conventional bioinspired omniphobic surfaces, the liquid repellency of the fabricated surface can be programmed by changing the surface microstructures via patterning of the film. Furthermore, the elasticity of the omniphobic film is suitable for controlling the repellency through external stimuli. The method presented here for the fabrication of lubricant‐infused omniphobic microstructured surfaces is also simple, cost‐effective, and can be scaled for large area fabrication.     

Increasing the speed of microstrip-line-type polymer-dispersed liquid-crystal loaded variable phase shifter

We discuss a method for the production of microwave polymer-dispersed liquid-crystal devices. We also show how to obtain a fine grained uniform fibrous polymer network. We then measure how the microwave-band dielectric properties and response-time characteristics of microstrip-line-type polymer-dispersed liquid-crystal devices vary with polymer concentration, and we measure how their response-time characteristics vary with the thickness of the polymer-dispersed liquid-crystal layer. With a layer thickness of 50 /spl mu/m, an applied voltage of 100 V and a polymer concentration of 7 wt%, we show that the decay time can be reduced to approximately 1/30th that of a plain liquid crystal at the expense of an increase in rise time of approximately 2.5 times and a deterioration of dielectric birefringence of approximately 50%. Finally, we discuss the results obtained with a prototype polymer-dispersed liquid-crystal loaded variable phase shifter in the 15-GHz band. By comparing the variable phase and response time of this phase shifter with basic experimental data obtained by the microwave resonance method, we verified the validity of these values.     

Application of nonlinear regression in the development of a wide range formulation for HCFC-22

An equation of state has been developed for HCFC-22 for temperatures from the triple point (115.73 K) to 550 K, at pressures up to 60 MPa. Based on comparisons between experimental data and calculated properties, the accuracy of the wide-range equation of state is ±0.1% in density, ±0.3% in speed of sound, and ±1.0% in isobaric heat capacity, except in the critical region. Nonlinear fitting techniques were used to fit a liquid equation of state based onP--T, speed of sound, and isobaric heat capacity data. Properties calculated from the liquid equation of state were then used to expand the range of validity of the wide range equation of state for HCFC-22.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Electrochemical properties of V2O5/carbon composite electrodes in aqueous solutions

The reaction mechanism of V₂O₅ xerogel and the electrode properties of V₂O₅/carbon composites in an aqueous electrolyte solution were examined to obtain high-performance electrodes for rechargeable proton batteries. Based on the results of the chemical analysis of the electrode, proton intercalation is suggested to be the dominant reaction mechanism. By using the relationship between the capacity and current density of a thin-film electrode consisting of V₂O₅ xerogel, the diffusion coefficient in the V₂O₅ xerogel was determined to be 8 ± 1 × 10^?11 cm² s^?1. The V₂O₅/carbon composite electrode was prepared by drying a homogeneous dispersion of carbon particles in the V₂O₅ sol. The composite electrodes showed a large capacity of 460 mAh g^?1 at a current density of 1 A g^?1 and maintained a relatively large capacity of 160 mAh g^?1 at 100 A g^?1. These properties were attributed to the homogeneous microstructure of the V₂O₅/carbon composites. The V₂O₅/carbon composite electrodes were thus revealed as high-performance electrodes with large capacities and excellent high-rate capabilities.     

A case of HTLV-I associated polyradiculoneuropathy and cerebral white matter lesions with smouldering type adult T cell leukemia

Chronic myelogenous leukemia (CML) is associated with an acquired karyotypic abnormality, the Philadelphia (Ph) chromosome, in 95% of cases. The Ph chromosome is the product of a balanced translocation that results in a hybrid gene that is considered essential for the pathogenesis of this disease. We have found a complex translocation involving chromosomes 9, 12, and 15 in a 42-year-old Haitian male with the clinical findings of CML. Complex translocations have been shown to result in the masking of the Ph chromosome. We used a mixture of two BCR-specific DNA probes for Southern blot analysis in order to test this hypothesis in our patient. High-molecular weight DNA was digested with the restriction enzymes BglII, BamHI and HindIII. The BglII digestion revealed the presence of two abnormal fragments of 3.9 and 3.0 kb and the BamHI digestion an abnormal 15-kb fragment. These data suggest there is a breakpoint in region 2 of M-bcr. The identification of this breakpoint confirms our hypothesis that a rearrangement involving 22q11 has occurred in the leukemic cells of our patient. A secondary translocation involving chromosomes 12 and 15 has hidden the effects of this translocation. Combined cytogenetic and molecular analysis establishes the karyotype of our patient as 46,XY,t(9;12;15;22)(q34;q12;q21;q11).     

Melatonin treatment for circadian rhythm sleep disorders

We administered 1-3 mg melatonin to 11 patients (eight men, three women, aged 16-46 years) with circadian rhythm sleep disorders; nine with delayed sleep phase syndrome and two with non-24-hour sleep-wake syndrome. Sleep logs were recorded throughout the study periods and actigraph and rectal temperature were monitored during treatment periods. Melatonin was administered 1-2 h before the desirable bedtime for expected phase-shifting, or 0.5-1 h before habitual bedtime for gradual advance expecting an hypnotic effect of the melatonin. Melatonin treatments were successful in 6/11 patients. Timing and dose of melatonin administration, together with its pharmacological properties for circadian rhythm sleep disorders, should be further studied.     

Cloning and characterization of a cDNA encoding a novel heterogeneous nuclear ribonucleoprotein-like protein and its expression in myeloid leukemia cells

Breast cancer is the second leading cause of cancer-related deaths among women in the United States. Approximately 180,000 new cases of breast cancer are diagnosed each year and a quarter of these are fatal. Early detection is a key to survival of these patients. Unfortunately, no definitive markers are available to diagnose breast cancer at early stages. Identification of such early markers, therefore, is an important priority in breast cancer research. In order to identify early markers, we have focussed on understanding the molecular mechanisms that can lead to conversion of the normal mammary epithelial cells into precancerous immortal cells. Over last several years, we have developed in vitro models of human mammary epithelial cell immortalization which have allowed us to invoke the critical roles of the known tumor suppressor pathways in the maintenance of the untransformed state of mammary epithelial cells. These models are now being used to identify novel genes whose expression is important for normal mammary epithelial cell growth and whose altered expression contributes to breast cell transformation. Characterization of the molecular machinery whose alterations result in early preneoplastic transformation should help identify candidate genes for evaluation as potential early diagnostic markers.