Diffusion-weighted imaging in prostate cancer

Magnetic Resonance Materials in Physics, Biology and Medicine - Diffusion-weighted imaging (DWI), a key component in multiparametric MRI (mpMRI), is useful for tumor detection and localization in...     

Noise parameter modeling for InP-based pseudomorphic HEMTs[InAlAs-InGaAs]

The effect of electron mobility (μ_n) on noise properties for InP-based pseudomorphic HEMTs has been analyzed based on the impedance field model. The analysis predicts that increasing μ _n improves the minimum noise figure (F_min) and associated gain not only because the unity current gain cut-off frequency increases but also because the source resistance is reduced. The analysis also predicts that increasing μ_n reduces the input noise resistance due to higher transconductance but hardly influences the noise-optimum impedance. Furthermore, it is predicted that the decrease in F_min with increasing μ_n becomes less significant above 11000 cm²/Vs due to larger diffusion noise. Calculated results compare well with the measured scattering and noise parameters for In_xGa_1-xAs(x=0.53, 0.7, and 0.8) channel devices. Similar dependence of noise parameters on μ_n is shown in the theoretical and experimental results     

The long-term course of spike and wave complexes in the waking EEG of chronic schizophrenics

Nineteen chronic schizophrenics (8 males and 11 females) showed at least one spike and wave complex (SpW) in their rested-awake EEGs during long-term neuroleptic treatment. The age at the first appearance of the SpW ranged from 16 to 60 years, and the duration of neuroleptic medication preceding its appearance was from 1 to 35 years. Two types of SpW waveform were discriminated; one was a diffuse high voltage isolated 3.5-4 Hz SpW complex, and the other a diffuse moderate voltage 5-6 Hz SpW burst. In EEG studies repeated over the long-term, the presence of SpW was transient in 11 cases, intermittent in 5 cases, and continuous in 3 cases. Three patients had generalized tonic-clonic clinical seizures; two of their EEGs did not show SpW until after the onset of seizures. All three responded well to adjunctive anticonvulsant therapy. The other 16 patients exhibited SpW but did not have clinical seizures with or without prophylactic use of anticonvulsants. The SpW in the EEG of chronic schizophrenics might be an indicator of predisposition for seizure, but it is not a good predictor of seizure.     

Concentration profile of sodium ion in gas absorption

In this work the absorptions of sulphur dioxide and hydrogen sulphide into jelly containing one of sodium chloride, sodium sulphite and sodium hydroxide aqueous solutions have been carried out. After a certain exposure time, the jelly was cut into slices in which the concentration of sodium ion was measured by a flame spectrometer. The concentration of sodium ion at the gas—jelly interface was considerably higher than that in the bulk except for the H₂SNaCl system. Experimental results are compared with the analytical solution based on the molecular penetration theory in which the molecular diffusivity is replaced by the effective ionic diffusivity, and it is found that both dissociation and reaction effects influence the concentration profile of sodium ion in the liquid phase.     

Gel permeation chromatography using controlled-porosity glass. I. Polyacrylamide–formamide solution

The process of characterizing polyacrylamide and its partially hydrolyzed materials by gel permeation chromatography was examined. The use of controlled-porosity glass and formamide as the stationary phase and the eluent, respectively, resulted in chromatographic behavior in accord with the hydrodynamic volume concept for polyacrylamide fractions. The addition of a salt (KCl) to the eluent was found to retard the elution of the hydrolyzed polyacrylamide.     

Synthesis of Metal Oxide Particles Using Reaction Route from Rare-Earth Metal-EDTA Complexes

Highly dense, spherical yttria (Y₂O₃) and erbia (Er₂O₃) particles were synthesized from their corresponding metal-ethylenediaminetetraacetic (EDTA) complexes. The EDTA·Y·H and EDTA·Er·H complexes were prepared in powdered form. These complexes were used as the staring materials for synthesis of the Y₂O₃ and Er₂O₃ particles. The particles were synthesized using an H₂-O₂ flame produced with a commercial flame spray apparatus. Crystalline structure, surface and cross-sectional morphologies, and elemental distribution of the synthesized particles were investigated. It was confirmed that the crystalline phases of the Y₂O₃ and Er₂O₃ particles were homogeneous. In addition, the elemental distribution of the particles was uniform. These results indicate that dense, spherical particles of Y₂O₃ and Er₂O₃ have been synthesized with EDTA·Y·H and EDTA·Er·H complexes, respectively.     

Total Synthesis and Structural Revision of Kasumigamide,and Identification of a New Analogue

Kasumigamide is an antialgal hybrid peptide–polyketide isolated from the freshwater cyanobacterium Microcystis aeruginosa (NIES-87). The biosynthetic gene cluster was identified from not only the cyanobacterium but also Candidatus “Entotheonella”, associated with the Japanese marine sponge Discodermia calyx. Therefore, kasumigamide is considered to play a key role in microbial ecology, regardless of the terrestrial and marine habitats. We now report synthetic studies on this intriguing natural product that have led to a structural revision and the first total synthesis. During this study, a new analogue, deoxykasumigamide, was also isolated and structurally validated. This study confirmed the presence of the unusual pathway in the biosynthesis of a hybrid peptide–polyketide natural product.     

Video object segmentation using color-component-selectable learning for self-organizing maps

In this article, self-organizing-map-based video object segmentation is proposed, assuming that either Y-quantification or HSV-quantification can be systematically selected. Given a video sequence, the value of the probability density function for each component value is calculated according to a kernel estimation at the first frame. Some areas randomly chosen from the background are then examined, using each component value, to judge whether or not they include the target object. The quantification is determined so that the frequency of occurrence of false extractions can be reduced. The data presented to the maps are generated based on the selected quantification. Experimental results show that the proposed method recognizes the target object well.