Use of biplane transesophageal echocardiographic guide in radiofrequency catheter ablation of Wolff-Parkinson-White syndrome with left side Kent bundle

We report 2 patients with Wolff-parkinson-White Syndrome, who underwent radiofrequency (RF) catheter ablation under observation by biplane transesophageal echocardiography. One of the patients had Kent bundle in the lateral wall of the left ventricle, and the tip of the catheter could be easily confirmed with transverse views. Since perforation was observed where the valve was attached to the posterior leaflet of the mitral valve during the 39th administration of RF energy, ablation was discontinued. The other patient had Kent bundle in the posterior septum of the left ventricle. The tip of the catheter could be easily confirmed with sagittal views. Ablation was successful after the 4th administration of RF energy, but particulate contrast echoes appeared from the site of the tip of the electrode which had been used for ablation during the 4th RF delivery. When the delivery of RF energy was discontinued, the contrast echo disappeared, and a thrombus was found at the tip of the removed catheter. TEE in RF catheter ablation was helpful for confirming the site of the tip of the catheter and for early detection of complications.     

Photoelectrochemical properties of SrFeNb oxides having perovskite structure

Photoelectrochemical properties of Sr₂FeNbO₆, Sr_1.9Fe_1.1NbO_6?x and Sr₃FeNb₂O₉ having the perovskite structures were investigated using sintered pellets to determine the energy gap and the flat-band potential and to evaluate the electrochemical stability against the anodic decomposition. The energy gap determined was 1.9 eV for Sr₃FeNb₂O₉ and 2.3 eV for both Sr₂FeNbO₆ and Sr_1.9Fe_1.1NbO_6?x. The flat-band potential of these materials was found to be ca. 0.1 V positive of the reversible hydrogen electrode in measured solutions. The onset potential of anodic photocurrents did not coincide with the flat-band potential, however, being more positive than that and varied with the kind of redox electrolyte chosen. Probable causes for this phenomenon are briefly discussed.     

Detection of an ellipse by use of a recursive least-squares estimator

A method for detecting an ellipse in an image by use of a recursive least-squares estimator is described. This method is based on classifying the behavior of parameters in a quadratic equation estimated by the estimator. The segmentation of an image is executed using a statistical measure called the adjacent separability factor. Noise elimination is performed by the expansion-contraction method and a contour for each region is extracted. Points on the contour are supplied to a recursive least-squares estimator in succession and the parameters in a quadratic equation are estimated recursively. It is possible to decide whether the contour is an ellipse by analyzing the behavior of an estimated parameter. A main feature of this method is the generality and the simplicity of the procedure.     

On the nature of rat hepatic and mouse olfactory sulfotransferases

Seasonal differences in the particle size fractions and mass loadings of household dust deposited on indoor surfaces were examined in four New Jersey homes. Housedust was collected during a 30-day period on non-electrostatic polyethylene sample plates on which a glass slide had been placed. In each home two samples were collected at a height of 1.5 m and two were collected at a height of 0.3 m above the floor. Dust samples were obtained from each home during a summer and winter collection period. Particle size measurement was completed using an adaptation of a Meridian ACAS 570 Interactive Laser Cytometer. Results indicated that the dust mass deposited on household surfaces during the summer was greater than during the winter. The arithmetic mean mass deposition rate for all houses was 0.37 +/- 0.13 microgram/cm2/day during the summer and 0.22 +/- 0.13 microgram/cm2/day during the winter. The total number of particles deposited, however, was greater during the winter than during the summer. The increase in winter time particle number was caused by greater numbers of particles with an equivalent spherical diameter < 2.5 microns. The most probable source of these particles was winter time combustion emissions within the residences and the subsequent particle deposition on household surfaces. The greater mass loadings measured on the low sampling plates during the summer were associated with a greater number of particles with an equivalent spherical diameter > 5 microns. In the winter, however, the particle mass and number loadings were similar at both heights. These results suggested that ventilation of the house during the summer allowed resuspended particles to enter which led to the higher levels of settled dust. Measurement of contaminant levels in housedust for exposure estimation therefore, should account for the seasonal and height differences in dust mass, and collect representative fractions of housedust that are available for human contact. Furthermore, since over 99% of the particles on indoor surfaces were < 50 microns any indirect sampling technique for dermal exposure estimation should have collection efficiencies similar to the hand of particles < 50 microns.     

500-Mb/s nonprecharged data bus for high-speed DRAM's

A nonprecharged data-bus scheme to enhance the intrinsic read data rate of DRAM cores is proposed. Eliminating the precharge cycle of the DRAM data bus can reduce the unit bit time. A differential partial response detection data-bus amplifier is also employed to detect signals on the nonprecharged data bus that are degraded by large intersymbol interference. To enhance the read operation further, column selections are overlapped by interleaved column decoders. To increase the operating margin of the nonprecharged data-bus read, a skew-controlled column-selection pulse generator was developed. An isolated sense-amplifier scheme increases the write data rate of the DRAM core. To verify these schemes, a 4-Mb DRAM was fabricated via 0.24-μm DRAM technology. These schemes realized a 500-Mb/s per data-bus read operation and a 100-Mb/s per data-bus write operation without an area penalty     

gp130 is involved in stretch-induced MAP kinase activation in cardiac myocytes

We have recently reported that mitogen activated protein kinase (MAP kinase) is activated by the stretch of the cultured cardiac myocytes in the angiotensin II deficient state in the angiotensinogen-deficient mice (Atg-/-), suggesting that factors other than the cardiac renin-angiotensin system are involved in the stretch-induced MAP kinase activation. We examined the contribution of cytokines using RX435, an anti-gp130 antibody. Leukemia inhibitory factor, which is one of the cytokines and has the common receptor subunit gp130, activated MAP kinase and the response was completely blocked by pretreatment of the Atg-/- cardiac myocytes with RX435. RX435 pretreatment greatly reduced stretch-induced activation of MAP kinase in Atg-/- cardiac myocytes. Interestingly, the same results were obtained in the cardiac myocytes of control mice. These results suggest that cytokine-gp130 may play a role in the stretch-induced MAP kinase activation independently of Ang II in cardiac myocytes.     

Induction of alternative splicing of HLA-B27 by bacterial invasion

This study introduces an attributional processing approach to study age differences in dispositional attributions. Dispositional attributions made in the context of relationship vignettes were examined among younger and older adults in 2 conditions (immediate and delayed rating conditions). By using a direct assessment of a 2-step process for making dispositional attributions, it was inferred that a spontaneous adjustment stage occurred following an initial characterization stage as a function of age group and content of vignettes. Older adults made lower dispositional ratings if they were given more time to think about the situations than if asked to make an immediate judgment. By contrast, younger adults made higher dispositional ratings if they were given more time to make the judgments. Qualitative analyses of schemas elicited by a subsample of participants for each vignette suggested a relationship between dispositional attributional ratings and content-evoked schemas.     

New GaAs-MMIC process technology using low-temperature depositedSrTiO3 thin film capacitors

The authors have developed a new GaAs-MMIC process technology using low-temperature deposited SrTiO₃ thin film capacitors which were combined with WSi-gate selfaligned FETs. The SrTiO₃ films were successfully deposited at 200°C by the RF magnetron sputtering method without degrading the FET characteristics. By integrating these on-chip SrTiO₃ bypass capacitors onto the GaAs IC, the parasitic inductance from the source to ground interconnection was successfully reduced and an enhanced gain characteristic was obtained for a self-biased amplifier circuit     

Design and implementation of a digital filter for beat-by-beatimpedance cardiography

A digital filter for thoracic impedance cardiography was developed and implemented on a 16-bit personal computer after examining the effect of respiratory movement on the first derivative of the thoracic impedance signal. Four male subjects exercised with a cycle ergometer at 100 and 150 W successively, after resting for 5 min. Thoracic impedance and its first derivative (dZ/dt) were recorded by a standard four-electrode cardiograph. The peak-power spectral densities of the pneumogenic (P_p,c) and the cardiogenic (P_p,c) components of dZ/dt were separated with a simultaneous recording of the ECG and thoracic circumferences. P_pP_c increased with each increment of work rate: 0.12 (0.05-0.19) at rest, 0.67 (0.49-0.97) at 100 W, and 0.97 (0.58-1.52) at 150 W