Lignocellulose–polymer composite. I

Bagasse grinded to different mesh sizes was used for the production of lignocellulose polymer composites. Samples of different polymer loads were prepared from crude-grafted bagasse with polymethyl methacrylate. A sodium bisulfite–soda lime glass system was used as an initiator for the grafting reaction. The properties of the resulting composites have been found to be affected by both the polymer load and the mesh size of the ground bagase. Grafting in the absence of soda lime glass from the initiator system was successful, and the properties of the composite produced from the prepared samples differed greatly from those containing glass. Other oxides, namely, copper (cupric) oxide and iron (ferric) oxide, were used in replacing glass in the initiator system. Some of the properties of the composite containing the latter were deteriorated. A composite from the true-grafted sample (homopolymer free) showed improvement in some of the properties, while the others deteriorated. Composites prepared from impregnated bagasse with polymer or homopolymer behaved differently in their properties and from those from crude-grafted samples, depending on the mesh size of the ground bagasse they are made from.     

Dielectric investigation of the molecular dynamics of blends (II): polymers with dissimilar molecular architecture (PS/TMPC blend)

The molecular dynamics of polystyrene/tetramethyl polycarbonate (PS/TMPC) blends were investigated using dielectric spectroscopy in the frequency and temperature ranges 10^?2?10⁷ Hz and 50–220°C, respectively. Blends with different compositions, namely 12.5, 25, 50, 75 and 87.5 wt% PS/TMPC were found to be compatible over the entire composition range and showed one glass relaxation process corresponding with the transition observed by calorimetric measurements. It was found that neither the kinetics or the distribution of relaxation times of the local process observed in pure TMPC were affected by blending. This fact implies that the local environment of the segments is not changed upon blending. Furthermore, these blends showed that the blending of TMPC with weakly polar polystyrene does not cause any change in the dipolar interaction of the TMPC segments, so that the relaxation strength varies linearly with composition. It is concluded that the polymeric chains of the TMPC and PS are not mixed at a segmental level, but at a higher structural level lying somewhere between segmental and molecular. This conclusion is in good agreement with that obtained in the case of blends composed of polymers with similar molecular architecture.     

Prospective controlled randomized study of in vitro fertilization versus intracytoplasmic sperm injection in the treatment of tubal factor infertility with normal semen parameters

We report a case of aortitis syndrome, in which carotid ultrasonography was a useful approach for the diagnosis. A 21-year-old woman was admitted to our hospital for persistent fever. No specific physical findings or laboratory abnormalities were observed except high fever and marked increase of erythrocyte sedimentation rate and c reactive protein. Since clinical trial of antibiotics and antituberculosis agents resulted in no effectiveness, prednisolone was started, but the effect was limited. After that, she complained of the neck pain, and vascular murmur became apparently audible at the pain site. Ultrasonography of the carotid artery revealed the smooth lumen and homogeneous, non-hyperechoic intimal thickening. Then aortography confirmed the diagnosis of aortitis syndrome. Cyclophosphamide combined with steroid therapy diminished the disease activity. In this case, carotid ultrasonography gave us the important information to enforce the aortography. If ultrasonography of the carotid artery has been popularized for aortitis syndrome, and its findings have been standardized, non-invasive diagnosis of this disease will be taken a step forward.     

Mu and kappa opioid receptors in periaqueductal gray and rostral ventromedial medulla

The periaqueductal gray (PAG) and rostral ventromedial medulla (RVM) are important brain stem pain modulating regions. Recent evidence suggests that kappa opioids antagonize the effects of mu opioids in the RVM. However, the anatomical relationship between mu and kappa opioid receptors in PAG and RVM is not well characterized. This study examined relationships between mu and kappa opioid receptor immunoreactivity (IR) and mRNA in PAG and RVM. Brain slices were processed for either immunocytochemistry or in situ hybridization. We found considerable anatomical overlap of mu and kappa opioid IR and mRNA in the RVM and PAG. These results provide an anatomical basis for recent behavioral and electrophysiological findings in RVM, and suggest modulatory interactions between mu and kappa opioids in PAG.     

Analysis of microwave ovens loaded with lossy process materials using the transmission-line-matrix method

The transmission-line-matrix (t.l.m.) numerical analysis technique is used in this paper to evaluate resonant frequencies and field parameters of the generated modes in microwave ovens loaded with lossy process materials. Analysis is made for the variation of resonant frequencies with the loss factor of the loading material. Temperature rise profile through the load is predicted from the calculated results of field parameters of sustained modes. The demonstrated data are for the dimensional parameters of a rectangular cavity of a commercial microwave oven operating at the standard heating frequency 915 MHz.     

Superconducting millimeter-wave E-plane filters

The authors report on the measured performance of a three-pole E-plane filter constructed from high-T_c superconducting bulk materials at 34.5 GHz. Experimental results are presented for the insertion loss and return loss of the filter at 77 K. The problems associated with the use of bulk materials at the millimeter-wave range are addressed. Other possible superconducting waveguide filter configurations are proposed. While the experimental results are taken at low input power level, the current distribution inside the filter structure is calculated, and the power handling capability of the superconducting filter is discussed     

Determination of the effective mass for highly degenerate copper selenide from reflectivity measurements

An investigation was made of the plasma reflection of light and the results were used to find the effective mass of highly degenerate copper selenide,p>10²⁰ cm^–3, as a function of carrier concentrationp. The study of the temperature dependence of effective mass, electrical conductivity, thermoelectric power and Hall mobility carried out in the present work gives an idea of the nature of the valence bands in these materials.