Successful surgical repair of left atrial dissection after mitral valve replacement

A rare case of left atrial dissection after mitral valve replacement is reported. Low output syndrome developed in the immediate postoperative period. Cardiac catheterization showed marked elevation of the pulmonary wedge pressure, and left ventriculography revealed massive paraprosthetic leakage with left atrial dissection. At the reoperation, the dissecting cavity was successfully closed from inside the left atrium under cardiopulmonary bypass. We consider this complication another variation of an atrioventricular discontinuity after mitral valve replacement.     

Diel rhythms of calling behavior and pheromone production of oriental tobacco budworm moth,Helicoverpa assulta (Lepidoptera: Noctuidae)

Both calling behavior and titer of (Z)-9-hexadecenal (Z9-16: Al), the major sex pheromone component ofHelicoverpa assulta, in pheromone glands showed distinct diel periodicity, and these two were synchronous. Calling was most actively performed and the pheromone titer reached a maximum from 2 to 6 h after lights-off. During photophase, no calling was shown and only a relatively small amount of Z9-16:A1 was detected. However, there was a time lag of a few days between peak calling activity and maximum pheromone titer. The pheromone titer was maximal from age 1 day to age 5 days and thereafter decreased while calling was most actively performed after age 3 days. Titers of three minor components, hexadecenal, (Z)-11-hexadecenal, and (Z)-9-hexadecenyl acetate, showed similar daily fluctuation patterns to that of Z9-16:Al, but relative to the titer of Z9-16:Al, the titer of the two aldehyde components remained relatively constant whereas that ofZ9-16:Ac increased in the late scotophase.     

Wear resistant coating of cemented carbides and high speed steels by chemical vapour deposition

Ti(N, C, O), which has been chosen as a coating material for cutting tool inserts, was prepared on cemented carbides and high speed steels by chemical vapour deposition via a gas mixture of TiCl₄, H₂, N₂, CH₄ and CO₂ under reduced pressure. This coating layer is characterized by fine grain size and freedom from porosity. The coated tool inserts show excellent cutting performance.     

REFLICS: Real-time flow imaging and classification system

An accurate analysis of a large dynamic system like our oceans requires spatially fine and temporally matched data collection methods. Current methods to estimate fish stock size from pelagic (marine) fish egg abundance by using ships to take point samples of fish eggs have large margins of error due to spatial and temporal undersampling. The real-time flow imaging and classification system (REFLICS) enhances fish egg sampling by obtaining continuous, accurate information on fish egg abundance as the ship cruises along in the area of interest. REFLICS images the dynamic flow with a progressive-scan area camera (60 frames/s) and a synchronized strobe in backlighting configuration. Digitization and processing occur on a dual-processor Pentium II PC and a pipeline-based image-processing board. REFLICS uses a segmentation algorithm to locate fish-egg-like objects in the image and then a classifier to determine fish egg, species, and development stage (age). We present an integrated system design of REFLICS and performance results. REFLICS can perform in real time (60 Hz), classify fish eggs with low false negative rates on real data collected from a cruise, and work in harsh conditions aboard ships at sea. REFLICS enables cost-effective, real-time assessment of pelagic fish eggs for research and management. Received: 12 April 2000 / Accepted: 6 July 2000     

Interactive segmentation of the cerebral lobes with fuzzy inference in 3T MR images.

Measurement of volume and surface area of the frontal, parietal, temporal and occipital lobes from magnetic resonance (MR) images shows promise as a method for use in diagnosis of dementia. This article presents a novel computer-aided system for automatically segmenting the cerebral lobes from 3T human brain MR images. Until now, the anatomical definition of cerebral lobes on the cerebral cortex is somewhat vague for use in automatic delineation of boundary lines, and there is no definition of cerebral lobes in the interior of the cerebrum. Therefore, we have developed a new method for defining cerebral lobes on the cerebral cortex and in the interior of the cerebrum. The proposed method determines the boundaries between the lobes by deforming initial surfaces. The initial surfaces are automatically determined based on user-given landmarks. They are smoothed and deformed so that the deforming boundaries run along the hourglass portion of the three-dimensional shape of the cerebrum with fuzzy rule-based active contour and surface models. The cerebrum is divided into the cerebral lobes according to the boundaries determined using this method. The reproducibility of our system with a given subject was assessed by examining the variability of volume and surface area in three healthy subjects, with measurements performed by three beginners and one expert user. The experimental results show that our system segments the cerebral lobes with high reproducibility.     

New Thin-Film Multijunction Thermal Converter Design for Improved High-Frequency Performance

New thin-film planar multifunction thermal converters (PMJTC) were developed to improve the high-frequency ac-dc transfer differences. The heater resistor and thermocouples of these PMJTCs were produced on different substrates: an AIN chip for the heaters and polyimide film for the thermocouples, using simple fabrication processes. The thermocouples were moved from the conventional high-potential heater position, and placed close to the ground electrode of the input circuit. This new configuration upgrades the performance of ac-dc transfer differences above 10 kHz by improving both the electromagnetic coupling between the heater and thermocouples and the output resistance of thermocouples. Using a high thermal conductivity AIN substrate, through which heat is conducted from the heater to the hot junctions of the thermocouples, almost the same sensitivity as that of PMJTCs on silicon is obtained.     

Responsiveness of electric resistance of polymer-grafted carbon black/alumina gel composite against solvent vapor and solute in solution

The carbon black/alumina gel composites were prepared by sol-gel reaction of aluminum isopropoxide in the presence of polymer-grafted carbon black. The electric resistance of the alumina gel composite from polymer-grafted carbon black was very sensitive to vapor of good solvent for grafted polymer on carbon black: the electric resistance of the alumina gel composite suddenly decreased in solvent vapor and returned to initial resistance when it was transferred into dry air. The effect of surface area and particle size of carbon black on the responsiveness was also investigated. In addition, the electric resistance of the alumina gel composite was found to respond to water and methanol in n-hexane and diethyl ether.     

Nanocrystallization of Fe73.5Si13.5B9Nb3Cu1 soft-magnetic alloy from amorphous precursor in a magnetic field

The effect of a magnetic field on the nature of nanocrystallization from a melt-spun Fe_73.5Si_13.5B₉Nb₃Cu₁ amorphous precursor has been studied with the aim of controlling microstructures and magnetic properties. Annealing for magnetic crystallization was carried out at temperatures between the Curie temperature of the amorphous phase (586 K) and that of the crystalline phase (920 K). It was found that the {110} texture component in crystallized α-Fe(Si) phase increased in importance with increasing magnetic-field strength. An X-ray diffraction analysis based on the Shultz method revealed that the magnetic field caused preferential formation of {110}-oriented nuclei. In addition, the applied field enhanced crystallization kinetics, particularly the nucleation rate. No significant difference in grain growth behavior was observed as a result of applying a magnetic field. We therefore conclude that the development of the {110} texture by magnetic crystallization is predominantly attributable to preferential nucleation, rather than preferential growth, of {110}-oriented nuclei. The saturation magnetization of nanocrystallized specimens, evaluated using a vibrating sample magnetometer (VSM), was increased by the application of a magnetic field up to 4T during nanocrystallization.