Detection and Quantitation of Left-to-Right Shunts from Radionuclide Angiocardiography Using the Homomorphic Deconvolution Technique

The homomorphic filtering method is described for the detection and quantitation of left-to-right shunts from radionuclide angiocardiography. First, the method is investigated theoreticatly and numerically using a realistic model with systemic recirculation. It is demonstrated that even in a noisy situation the shunt flow fraction can be relatively well estimated, if only the characteristics of the fiters used are suitable. Second, the method is applied to real data, i.e., the pulmonary time-activity curves from radionucUde anglocardiography. The presence or absence of a left-to-right shunt is determined using the ratio AT/MTT. The pulmonary-to-systemic flow ratios calculated from the areas of the two decomposed curves are compared with those from oximetry at cardiac catheterization. Good agreement between the Qp/Qs ratios calculated by oximetry and radionucUide angiocardiography is obtained.     

Capillary gas-liquid chromatographic separation of oxo and oxo-hydroxy bile acid isomers of theallo and normal series

Capillary gas-liquid chromatographic separation was studied for 60 oxo and oxo-hydroxy bile acids of theallo (5α-H, A/B-trans) and normal (5β-H, A/B-cis) series, which differ from one another in the number, position, and configuration of oxo and hydroxy groups at positions C−3, C−4, C−6, C−7, and/or C−12. Good separation of the isomers was achieved by the use of an aluminum-clad fused-silica capillary column coated with bonded and cross-linked methyl polysiloxane.     

Liver phosphatidylcholine hydroperoxidation provoked by ethionine-containing choline-deficient diet in mice

It is shown that peroxidation of phosphatidylcholine (PC) is enhanced in liver of mice fed a hepatocarcinogenic choline-deficient diet containing 0.1% w/w ethionine. Mice were divided into 4 groups and fed for 3 weeks one of the following diets: choline-supplemented; choline-supplemented containing ethionine; choline-deficient; and choline-deficient containing ethionine. Phosphatidylcholine hydroperoxide (PCOOH) of liver lipids was measured by high performance liquid chromatography using a chemiluminescence detector. Mice fed a choline-deficient diet containing ethionine showed 6-fold higher PCOOH levels than the choline-supplemented control mice: the PCOOH/PC molar ratios of liver lipids were 32.3×10⁻⁵ and 5.6×10⁻⁵, respectively. In addition to this remarkable degree of lipid peroxidation in liver of mice fed the choline-deficient diet containing ethionine, we also observed a significant liver fatty infiltration, a decrease in plasma and liver α-tocopherol, and an increase in liver injury-indicative enzyme activities. Also, marker enzymes for hepatocarcinogenesis, glucose-6-phosphatase and γ-glutamyl transpeptidase were affected. These data suggest that enhanced hydroperoxidation of phosphatidylcholine may participate in hepatocarcinogenesis provoked by choline deficiency in the presence of ethionine.     

Characterization of germanium implanted Si1−xGex layer

Characterization of a Si_1−xGe_x layer formed by high-dose germanium implantation and subsequent solid phase epitaxy is reported. Properties of this layer are obtained from electrical measurements on diodes and transistors fabricated in this layer. Results are compared with those of the silicon control devices. It was observed that the germanium implantation created considerable defects that are difficult to eliminate with annealing. These defects result in boron deactivation in the p-type regions of the devices, giving rise to larger resistance. Optimization of the device structure and fabrication process is discussed.     

A Hybrid Fast Multipole Pseudo-Spectral Time Domain Method

The major computation cost of pseudo-spectral method comes from the evaluation of differentiation matrix multiplication. In the past, uniform or Chebyshev collocation points are used for sampling. The differentiation matrix multiplication was evaluated by fast Fourier transform (FFT) or fast cosine transform (FCT), in order to reduce the computation complexity from O(N²) to O(N log(N)). However, the intrinsic properties of FFT or FCT may cause the wraparound effect and Gibbs phenomenon. Moreover, FFT or FCT is not applicable to other collocation points such as Legendre and Hermite. In order to improve the accuracy and applicability of the pseudo-spectral method, the fast multipole method (FMM) is exploited to substitute the FFT or FCT. By making use of the similarity of the N-body problem and the collocation problem, a new FMM-based pseudo-spectral time domain method is developed in this paper.     

Design of Fully Balanced Analog Systems Based on Ordinary and/or Modified Single-Ended Opamps

The system architectures, which allow a high performance fully balanced (FB) system based on ordinary/modified single-ended opamps to be implemented, are investigated and the basic and general requirements are formulated. Two new methods of an FB analog system design, which contribute towards achieving both a high performance IC system implementation and a great reduction of the design time are presented. It is shown that a single-ended system based on any type of opamp (rail-to-rail, constant g _m , etc.), realized in any technology (CMOS, bipolar, BiCMOS, GaAs), can be easily and effectively converted to its FB counterpart in a very practical way. Using the proposed rules, any FB system implementation with opamps (data converter, modulator, filter, etc.) requires only a single-ended system version design and the drawbacks related to a conventional FB system design are avoided. The principles of the design are pointed out and they are verified by experimental results.     

Fabrication of porous ZnO via electrochemical etching using 10 wt% potassium hydroxide solution

We described the fabrication of porous ZnO using the electrochemical etching method. ZnO thin films deposited by radiofrequency sputtering were etched electrochemically using 10 wt% KOH solution as an etching medium to obtain porous ZnO surface structure. A constant voltage of 15 V was applied to enhance the etching process. The etched samples were then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy to examine their structural and optical properties. XRD spectra showed that by performing the electrochemical etching process, porous ZnO could be obtained without severely deteriorating the crystallinity of the samples. Moreover, SEM characterization revealed that hillock-type porous ZnO was fabricated successfully. In addition, the cross-sectional SEM images revealed that there were only minimal changes in the layer thickness after the ZnO had been etched for various lengths of time. This finding shows the dominance of the vertical etching process. Notably, the intensity of PL spectra increased and the PL excitation peak exhibited a red shift trend as the etching time increased. These observations are due to the increase of the surface to volume ratio of the ZnO surface and the strain relaxation along the dislocation and grain boundary.     

S-parameter based technique for simultaneous switching noiseanalysis in electronic packages

A method based on S-parameters is developed for the analysis of simultaneous switching noise (SSN) in electronic packages. A two-port Z matrix of the package pin/trace, and the coupling between the pins/traces are modeled by analytical equations. SSN is analyzed as a function of the number of switching drivers and switching time. Frequency domain measurements are performed to demonstrate the accuracy of the model. The modeling methodology is applied to both leaded and area array packages     

Negative giant surface potential of vacuum-evaporated tris(7-propyl-8-hydroxyquinolinolato) aluminum(III) [Al(7-Prq)3] film

Negative giant surface potential was realized in a vacuum-evaporated film of tris(7-propyl-8-hydroxyquinolinolato) aluminum(III) [Al(7-Prq)₃]. Electroabsorption response of the film presented an inverted polarity to that of tris(8-hydroxyquinolinolato) aluminum (Alq₃), suggesting opposite noncentrosymmetry of molecular orientation. Asymmetric dice model with molecular geometric effect has been proposed, and propyl substitution at 7 position of the ligands was indicated to affects the molecular posture on the surface to invert the polarity of noncentrosymmetry. Our results opened a new possibility of controlling molecular orientation in a film for device applications.