Leiomyoma of the stomach as a cause of hemorrhage from the upper segment of the gastrointestinal tract

Two cases of female patients operated fo the tumors of the stomach are presented. Result of histologic examination was rather surprising in both cases--leiomyoma.     

Evaluation of intraductal ultrasonography in the diagnosis of pancreatic cancer

An intraductal ultrasound (IDUS) probe which is inserted via the papilla into the main pancreatic duct (MPD) was evaluated in the diagnosis of 20 patients with pancreatic cancer. The examination was successfully performed with the probe in 17 of the patients (85%). Due to its high frequency (30 MHz) the probe only allowed visualization of the ductal wall and the immediate periductal vicinity (up to about 10 mm). In 15 of the 20 patients the tumors were surgically resected and IDUS scanning was also performed in vitro on the resection specimens, the results being compared to those of histopathological examination. Of these 15 patients, 13 were found to have ductal adenocarcinomas and all but one had been unequivocally diagnosed as having such by ultrasonography (US), computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasonography (EUS). IDUS showed an echorich area (corresponding to cancerous canaliculi on histopathological examination), surrounded by an echopoor area (abundant stroma). This pattern was classified as type I. In two patients with intraductal papillary carcinomas in whom a conclusive diagnosis was not established on US, CT, EUS or ERCP, IDUS showed tumorous tissue with an inhomogeneous echopattern outside (type II) or within (type III) the duct. These results show that IDUS offers valuable diagnostic information complementary to ERCP especially in cases of intraductal papillary tumors. Whether the high resolution imaging of the duct and the paraductal tissue can be used to differentiate between the different forms of pancreatic lesions (inflammation, neoplasms) has to be investigated further.     

Impedance boundary method of moments with extended boundaryconditions

An improved impedance boundary method of moments is proposed to accurately and efficiently determine the propagation characteristics of multilayer planar optical waveguides whose refractive index profiles contain large step index changes or a graded-index region combined with step index changes. Extended impedance boundary conditions are used in the impedance boundary method of moments to replace regions in the waveguide structure which have refractive index discontinuities. Two methods for determining the extended boundary conditions include the standard transfer matrix method and a procedure utilizing a cascaded transmission line representation with successive calculation of input impedances. Simulation results show significantly improved convergence rates in the determination of propagation constants     

Radar detection of low-altitude targets in a maritime environment

Results from a unique analytical and experimental effort to assess low-altitude, short-range, radar detection capabilities in an evaporation ducting environment are presented. Within the horizon, the duct may shift the location of the last interference null several kilometers in range, which may cause nondetection at ranges where detection is expected and detection at ranges where detection is not expected. In addition, the evaporation duct may reduce the signal strength at ranges near the last interference peak so that detection of low-altitude, small-size, targets may not be possible until the target is much closer. At ranges near and beyond the horizon, radar signal strength depends both on the surface layer and on the mixed layer. To accurately model propagation in this region, knowledge of both surface layer and upper air meteorology Is required. An empirical model to merge the surface layer with the mixed layer has been developed. Comparisons of measured to calculated detection range indicate that the assumption of a standard atmosphere minimizes the variance of the difference between the detection ranges whereas ranges calculated using the measured surface meteorological conditions and a modified surface layer model minimizes the median of the difference     

Flicker sensitivity as a function of spectral density of external white temporal noise

Foveal flicker sensitivity at 0.5-30 Hz was measured as a function of the spectral density of external, white, purely temporal noise for a sharp-edged 2.5 deg circular spot (mean luminance 3.4 log phot td). Sensitivity at any given temporal frequency was constant at low powers of external noise, but then decreased in inverse proportion to the square root of noise spectral density. Without external noise, sensitivity as function of temporal frequency had the well-known band-pass characteristics peaking at about 10 Hz, as previously documented in a large number of studies. In the presence of strong external noise, however, sensitivity was a monotonically decreasing function of temporal frequency. Our data are well described (goodness of fit 90%) by a model comprising (i) low-pass filtering by retinal cones, (ii) high-pass filtering in the subsequent neural pathways, (iii) adding of the temporal equivalent of internal white spatiotemporal noise, and (iv) detection by a temporal matched filter, the efficiency of which decreases approximately as the power -0.58 of temporal frequency.     

A randomized trial of cisplatin, etoposide and bleomycin (PEB) versus carboplatin, etoposide and bleomycin (CEB) for patients with 'good-risk' metastatic non-seminomatous germ cell tumors

BACKGROUND: Cisplatin-based combination chemotherapy will cure 70% to 80% of patients with metastatic non-seminomatous germ cell tumors but is associated with the possibility of severe neuro-, oto- and nephro-toxicities. Carboplatin, a cisplatin analogue, is an active drug in testicular cancer with a more favourable spectrum of side effects. In a randomized trial, the German Testicular Cancer Study Group compared a combination regimen of carboplatin, etoposide and bleomycin (CEB) to standard cisplatin, etoposide and bleomycin (PEB) chemotherapy for patients with 'minimal-' and moderate-disease' non-seminomatous germ cell tumors, according to the Indiana University classification. PATIENTS AND METHODS: PEB was given for three cycles at standard doses (given days 1-5), and the CEB regimen consisted of carboplatin (target AUC of 5 mg/ml x min) on day 1, etoposide 120 mg/m2 on days 1 to 3 and bleomycin 30 mg on days 1, 8 and 15. Four cycles of CEB were given, with the omission of bleomycin in the fourth cycle. Thus, the cumulative doses of etoposide and bleomycin applied in the two treatment arms were comparable. Fifty-four patients were entered on the trial, 29 were treated with PEB and 25 with CEB chemotherapy. Patients were stratified according to disease extent (minimal versus moderate) and the degree of tumor marker elevation. Thirty-two patients (59%) belonged to the group with minimal disease and low markers. RESULTS: No significant difference in response to chemotherapy was seen between the two arms, with CR rates of 81% for the PEB arm and 76% for CEB treatment. However, more patients treated with CEB (32% versus 13%) have relapsed after therapy, and 4 patients (16%) have died of disease progression after CEP in contrast to 1 (3%) after PEB therapy. The first interim analysis of negative events (relapse, vital tumor at secondary resection, death from disease and therapy-associated death) showed a significantly higher rate after CEB than after PEB therapy, and the trial was terminated early. After a median follow-up of 33 months for all patients, the calculation of negative events is still significantly in favour of PEB-treated patient, particularly since three late relapses > 2 years have been observed in the CEB arm (P = 0.03). CONCLUSION: This randomized trial demonstrates that even with the use of adequate doses of etoposide and full-dose bleomycin, carboplatin cannot altogether replace cisplatin in patients with testicular cancer. Treatment with the PEB regimen remains the standard approach in patients with 'good-risk' non-seminomatous germ cell tumors.     

Fabrication of a heterodyne receiver OEIC with optimized integration process using three MOVPE growth steps only

An optimized integration process is reported requiring only three epitaxial growth steps for the fabrication of an OEIC encompassing a single-mode laser, a waveguide element, and fast photodiodes. The process was applied to the fabrication of a heterodyne receiver including a semi-insulating buried heterostructure (SIBH)-DFB-laser with an output power of 14 mW and a side-mode suppression ratio greater than 40 dB, a 3-dB coupler, and high-speed balanced photodiodes with a bandwidth of 9 GHz. The laser can also be used as a transmitter laser exhibiting a modulation bandwidth of 11 GHz.     

State- and time-dependent routing in the NTT network

The purpose of state- and time-dependent routing (STR) is to achieve high performance despite unpredictable real-time traffic fluctuations, with minimum changes to existing switching software and operations systems. STR uses an appropriate combination of the two kinds of control, centralized and distributed. The article gives an overview of STR and its advanced call-level routing, describes the current STR network and the performance of STR with two examples from the NTT network, and addresses a dimensioning method for STR     

A new approach to the optimization of robust antenna arrayprocessors

The authors present a method for solving a class of optimization problems with nonsmooth constraints. In particular, they apply the method to the design of narrowband minimum-power antenna array processors which are robust in the presence of errors such as array element placement, look direction misalignment, and frequency offset. They first show that the constrained minimum power problem has a unique global minimum provided that the constraint set is nonempty. Then it is shown how the design problem derived directly from considerations of the sensitivity of the antenna array processor to errors can be transformed into a quadratic programming problem with linear inequality constraints which can be solved efficiently by the standard active set strategy. They also present numerical results for two types of nonsmooth constraints developed to provided robustness. These results confirm the effectiveness of the method     

Accurate and efficient computation of dielectric losses inmulti-level, multi-conductor microstrip for CAD applications

An approach to accurate and efficient computation of dielectric losses in complex microstrip structures is proposed. It can be used in lieu of lossy, full-wave solutions to provide accurate and efficient data for the CAD of multilevel, multiconductor MIC and MMIC structures. Results that are as accurate as lossy full-wave techniques over a wide range of frequencies, including the dispersive region, are obtained. In addition to providing accurate results, the method is up to three times faster, depending on the number and type of substrates or superstrates. Results for various multiconductor, multilevel structures that compare well with the lossy, full-wave approach and require significantly less computer time to compute are shown