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A novel, compact, and tunable lithium niobate (LN) planar waveguide loop structure composed of two Y junction reflectors is proposed for optical and radio frequency signal processing applications. The preliminary device shows a high quality factor of 6.5 x 10(4), due to the low propagation loss of the titanium-diffused LN waveguide. The tunability of the loop by electric field is estimated.

We discuss the generation, detection, and long-haul transmission of single-polarization differential quadrature phase shift keying (DQPSK) signals at a line rate of 53.5 Gbaud to support a net information bit rate of 100 Gb/s. In the laboratory, we demonstrate 10-channel wavelength-division multiplexed (WDM) point-to-point transmission over 2000 km on a 150-GHz WDM grid, and 1200-km optically routed networking including 6 reconfigurable optical add/drop multiplexers (ROADMs) on a 100-GHz grid. We then report transmission over the commercial, 50-GHz spaced long-haul optical transport platform LambdaXtremereg. In a straight-line laboratory testbed, we demonstrate single-channel 700-km transmission, including an intermediate ROADM. On a field-deployed, live traffic bearing Verizon installation between Tampa and Miami, Florida, we achieve 500-km transmission, with no changes to the commercial system hardware or software and with 6 dB system margin. On the same operational system, we finally demonstrate 100-Gb/s DQPSK encoding on a field-programmable gate array (FPGA) and the transmission of real-time video traffic. [ABSTRACT FROM PUBLISHER]

We demonstrate record 25.6-Tb/s transmission over 240 km using 160 WDM channels on a 50-GHz grid in the C+L bands. Each channel contains two polarization-multiplexed 85.4-Gb/s RZ-DQPSK signals, yielding a spectral efficiency of 3.2b/s/Hz in each band. [ABSTRACT FROM PUBLISHER]

We described a novel optical label swapping (OLS) technique for optical packet systems using frequency-shift-keying (FSK) optical labeling. High-speed optical FSK signal can be generated by using an external FSK modulator consisting of four optical phase modulators. The FSK modulator was based on optical single-sideband (SSB) modulation technique, and comprised of traveling-wave electrodes for high-speed frequency switching. We demonstrate 10 Gbps FSK transmission, and simultaneous modulation by FSK and intensity modulation (IM). OLS using double-sideband modulation was also demonstrated, where this technique can be used for a bundled wavelength-domain-multiplexing (WDM) channels without using an array of pumping light sources. [ABSTRACT FROM PUBLISHER]

A monolithically-integrated quad-parallel Mach-Zehnder optical modulator has been fabricated. 3 and 6 dB electro-optical bandwidths of Mach-Zehnder structures embedded in the modulator were evaluated as 22 and 36 GHz, respectively. By using the monolithic optical modulator, a 10 Gbaud 16-level quadrature amplitude modulation (QAM) signal was successfully obtained. [ABSTRACT FROM AUTHOR]

Crosstalk in a balanced bridge interferometric-type optical switch is highly suppressed by using Mach-Zehnder (MZ) structures as intensity trimmers. An imbalance in optical power is caused by deviations from the ideal dividing ratio of directional couplers in the switch, which causes an increase in the crosstalk. This imbalance was compensated for by adjusting the transmittances of the nested MZ structures. A crosstalk of less than 55 dB has been achieved even for alternating voltage signals. It is also shown that the crosstalk reduction is possible for a control voltage signal of more than 10 GHz, which is based on double-sideband suppressed-carrier modulation spectra measurement results. [ABSTRACT FROM PUBLISHER]

The authors propose a tunable delay line using an optical single-side-band modulator, a fiber Bragg grating and an optical fiber loop. The number of times light circulates in the loop can be controlled by the electric signal fed to the modulator. Packets of any lengths can go through the proposed delay line without any collisions, even if the length of the packet is larger than that of the delay loop. [ABSTRACT FROM PUBLISHER]

An optical frequency-shift-keying (FSK) modulator with a pair of Mach-Zehnder structures that can switch optical frequency is developed. The operation is demonstrated at a 10 Gbit/s FSK transmission conducted on a standard singlemode fibre of 60 km, where the FSK signal is demodulated by a fibre Bragg grating. [ABSTRACT FROM AUTHOR]

We propose and demonstrate a reconfigurable multilevel transmitter using a monolithically-integrated quad Mach-Zehnder in-phase/quadrature (QMZ-IQ) modulator with binary driving electronics. Different from previous parallel-integrated quadrature amplitude modulation (QAM) transmitter solutions, only one electrode is required to adjust the relative phase offset among embedded sub-Mach-Zehnder modulators in the proposed IQ superstructure. By feeding different RF driving electronics and operating the integrated modulator as different bias conditions, different advanced multilevel modulation formats, such as QAM and 8-ary phase-shift keying (8-PSK), could be synthesized. In this paper, a 40-Gb/s 16-QAM and a 30-Gb/s 8-PSK are generated using the proposed multilevel transmitter, respectively. Offline digital processing is employed for bit-error rates estimation and constellation reconstruction.

We propose and demonstrate an optical minimum-shift-keying (MSK) transmitter using a single-quad Mach-Zehnder (MZ) in-phase and quadrature modulator, where four sub-Mach-Zehnder modulators are monolithically integrated on a main MZ superstructure. Using the proposed transmitter, a MSK signal at bit rate of B could be successfully generated by orthogonally superposing two low-speed (B/2) carrier-suppressed return-to-zero differential phase-shift-keying streams with a relative time offset, 1/B. MSK signals at bit rate of 20 and 80 Gbits/s were successfully generated using the proposed MSK transmitter. A continuous changed phase trajectory of the obtained MSK was confirmed using a complex spectrum analyzer. The filtering tolerance of the MSK was also characterized using a bandwidth-variable tunable filter.

A 76-year-old woman was admitted to our hospital with cardiac tamponade. Chest computed tomography revealed a large tumor adjacent to the pulmonary artery, the center of which was demonstrated as a high density area without contrast medium. Coronary angiography revealed a large aneurysm consisting of coronary artery fistulas. An afferent vessel connected tangentially to the surface of the aneurysm, so blood flowed around along the inner wall of the aneurysm. A filling defect was demonstrated in the center of the aneurysm that indicated a thrombus. The cause of cardiac tamponade was seemed to be bleeding of the coronary artery fistulas. Coil embolization was performed, but recanalization occurred. Therefore, ligature of the fistulas and aneurismal resection were performed using a cardiopulmonary bypass. A fresh floating thrombus was found in the aneurysm.

We investigated an integrated optical modulator consisting of two Mach-Zehnder interferometers. The modulator can generate optical signals in various types of modulation formats, which have advantages for long-haul transmission, optical labeling, etc. By using a fabricated versatile optical modulator having traveling-wave electrodes designed for high-speed signals, we demonstrated generation of optical 40Gb/s frequency-shift-keying signals, which can be demodulated by an optical filter. 80Gb/s optical differential quadrature-shift-keying modulation was also demonstrated, where 40Gb/s in-phase and quadrature data were, simultaneously, fed to the modulator.

Purpose: The purpose of this study was to offer insight into the revisions needed for promotion of Maternal and Child Health Promotion Plans in the coming years., Methods: The maternal and child health promotion planning process and changes in maternal and child health services were surveyed by questionnaires to all municipalities in Japan., Results: Completed questionnaires were obtained from 2,362 municipalities (response rate: 72.6%) Replies from 2,202 municipalities, which had completed planning by March, 1998, were analyzed. Planning committees were established by 63.9% of municipalities, and working committees were set up in 55.4% of them. Members involved in the working committees were more limited when compared to the planning committees and only 9.3% of the committees had representatives from mothers. 37.5% of working committees held meetings more than 5 times. 56.0% of municipalities conducted hearings or questionnaire surveys of mothers and health personnel for assessment of maternal and child healthcare needs. Most prefectural public health centers provided statistical data for planning assistance. Public health center staff participated as planning members in 38.5% of municipalities, and a training program for the planning sponsored by health centers was utilized by 33.8% of municipalities. Only 18.3% of municipalities received support for explanation of the plans to the mayor and/or executive officers, only 12.1% received support for the management of the planning committees, and only 11.8% received support for needs analysis. Less than half of minicipalities conducted PR activities of the plans and progress management. A higher proportion conducted these activities in larger cities. After the planning process, 72.9% of municipalities started new projects according to the plans. However, 10.1% scrapped one or more projects. Changes in maternal and child healthcare services and promotion of coordination with other related organization were seen more in municipalities with a larger population. There were major differences found between prefectures with regards to the planning process, including the support from public health centers, and the effective use of plan reports, progress management, and changes in maternal and child healthcare services after the formulation of plans.

Objectives: This study evaluated the influence of extra-cardiac accumulation in technetium-99m-tetrofosmin myocardial single photon emission computed tomography (SPECT) imaging., Methods: Technetium-99m-tetrofosmin myocardial SPECT was performed in 247 patients from 1997 to 1999. To evaluate the sensitivity, 42 patients with inferior infarction were selected. To evaluate the specificity, 32 patients with no significant perfusion defect and low pretest likelihood (< 15%) of coronary artery disease and 13 patients with normal coronary angiography were selected. Firstly, the SPECT raw data were evaluated according to the effects of diaphragm and breast, the position and the degree of accumulation of the liver, gall bladder and intestine. Then, the myocardial tracer uptake was scored semiquantitatively from 0 (normal) to 4 (perfusion defect) in the 13 segments of the left ventricle., Results: The specificity was 86.7% and the sensitivity was 92.8%. Perfusion abnormality of the inferior wall was observed in 6 of 45 patients with a low pretest likelihood of coronary artery disease. These 6 patients were classified into the false positive group, and the other 39 patients were classified into the true negative group. The liver position and the liver accumulation on the stress images were significantly higher in the false positive group than in the true negative group (p < 0.001), but only the liver position on the rest images was significantly higher in the false positive group (p < 0.001). By estimating the defect 1 point lower for the high-positioned liver patients, specificity improved from 86.7% to 100% and sensitivity did not change., Conclusions: Inferior perfusion defect on technetium-99m-tetrofosmin myocardial SPECT of high-positioned liver patients needs to be evaluated with special caution.

Simultaneous assessment of stress perfusion and rest function is possible with gated single photon emission computed tomography (SPECT) using stress injected technetium-99m (99mTc) tetrofosmin (TF). The feasibility of dipyridamole stress electrocardiographic gated myocardial SPECT (GSPECT) with TF was examined as an alternative to conventional stress/rest imaging. Fifty-one patients underwent stress GSPECT. 740 MBq of TF was administered 3 min after dipyridamole infusion. GSPECT acquisition was performed one hour after the injection. Additional rest SPECT was performed on another day only in patients with abnormal perfusion on stress images. Perfusion and thickening were analyzed visually on 17 segments of the left ventricle. Percentage of wall thickening (%WT) was also calculated in 17 segments of the polar map. Thirty-two of 51 patients (63%) had normal stress perfusion and normal rest thickening. Nineteen of 51 patients (37%) had abnormal perfusion on stress images. Among 157 abnormal perfusion segments of the 19 patients, 139 segments (89%) had thickening and the rest (11%) had no thickening. %WT was higher in the reversible segments with or without thickening. There was better agreement for the identification of normal segments and the presence of reversibility between stress GSPECT and the conventional stress/rest study in patients without previous myocardial infarction than in those with previous myocardial infarction (89% vs 79%). These results suggest that stress GSPECT may substitute for conventional stress/rest perfusion study in patients without previous myocardial infarction, allowing shorter examination time and lower cost. However, stress GSPECT does not replace the need for rest perfusion study in patients with previous myocardial infarction, because of underestimation of viability, but %WT may eliminate this underestimation.