Preparation of carbon-coated W18O49 and its photoactivity under visible light

Carbon-coated W₁₈O₄₉ powders were prepared from the mixture of para-ammonium tungstate with poly(vinyl alcohol) by heat treatment in inert atmosphere at a temperature between 750 and 900 °C for 1 h. The synthesized W₁₈O₄₉ crystals had prismatic morphology in small size, less than 0.5 μm in diameter and about 1 μm in length. Carbon-coated W₁₈O₄₉ was shown to have photoactivity under visible light irradiation by comparing the concentration changes of methylene blue, phenol and dimethylsulfoxide with time under the irradiation of visible light to that in the dark. Photoactivity of W₁₈O₄₉ was supposed to be due to the formation of OH radicals on the basis of the degradation of dimethylsulfoxide, its quantitative transformation to methanesulfonic acid. Carbon coating seemed to have various roles: to reduce WO₃ to W₁₈O₄₉, to inhibit the sintering and crystal growth of W₁₈O₄₉ to keep them small size, and also to concentrate pollutants around W₁₈O₄₉ crystal by adsorption.     

Contrast-enhanced gradient-echo MR imaging of the head and neck: experimental and clinical assessment

To clarify the enhancement pattern of gradient-echo (GE) MR imaging, phantom experiments and 24 clinical examinations of the head and neck region were performed. Both long repetition time (TR) GE and short TR GE pulse sequences demonstrated an enhancement pattern similar to T1-weighted spin-echo imaging in phantom experiments, although the signal intensity of water and gadopentetate dimeglumine (Gd) solution was higher and the signal intensity of fat was lower with the GE technique. In clinical examinations, contrast-enhanced GE imaging was beneficial for tumors within fatty tissue, and for tumors with calcification or other magnetic susceptibility difference.     

Apoptosis and cellular proliferation in human epidermal squamous cell neoplasia

The structural changes in outpatient medical care in eastern Germany took place by far-reaching winding up of the outpatient departments. At the same time, many doctors from these institutions set up a practice. These changes also concerned the medical care by family doctors. It is assumed that as a result of these partly extensive changes there are also changes in the accessibility of the family doctor by outpatients. We will describe in this paper the level attained in Dresden, capital of Saxony in 1995 and 1996, from the point of view of the inhabitants. Existing problems are shown. In this connection, random samples of inhabitants of Dresden were interviewed by postal survey with questions on this subject in 1995 and 1996.     

Is angiographic spasm real spasm?

Systematic morphological study of the cerebral arteries was made in six autopsy cases of ruptured aneurysms. The time course of the arterial luminal narrowing was observed by repeated angiograms, and segments of the narrowed arteries were studied histologically. Various histological changes were found consistent with the angiographic findings. We have devided these into three stages according to the duration of the disease. In the acute stage (less than one day) the contraction of the medial smooth muscle cells may be the main cause of the luminal narrowing. In the subacute stage, arteries showed a reduction in lumen size with medial thickening, marked corrugation of the internal elastic lamina, and thrombus formation attached to the endothelial surface. If vasoconstriction remained localized to the same segment for several days, the intimal or medial thickening and thrombus might produce the luminal narrowing consistent with the angiographic narrowing. In the chronic stage (more than two weeks), most cases showed dilatation of the arterial lumen on angiography. These arteries showed frank necrosis of the smooth muscle cells histologically. In a case which demonstrated progressive luminal narrowing on angiograms over 2 weeks, the arterial wall showed luminal narrowing with cellulofibrous thickening of the intima and organization of the thrombus. The presence of these structural changes in the narrowed arteries seen at angiography seems to be very important for proper understanding and treatment of vasospasm.     

Centrifugal lipodystrophy of the face mimicking progressive lipodystrophy

We report a Japanese boy with centrifugal lipodystrophy. The initial lesion developed on the forehead as an area of erythema which showed centrifugal spread and central fading to leave a residual depression. Three years later, similar erythematous lesions appeared on the cheeks, and he developed a cadaverous appearance. A central depression on the upper trunk was surrounded by an erythematous border and there was right cervical lymphadenopathy. Histological examination revealed inflammatory changes in the subcutaneous fat. Although this patient showed the characteristics of both centrifugal and progressive lipodystrophy (partial lipodystrophy), we consider that he has centrifugal lipodystrophy of the face because of the overall features of the lesions.     

A surge-free intelligent power device specific to automotive highside switches

A novel type of intelligent power device (IPD), which is suitable for automotive monolithic high side switch with high current capability, is presented. An integration of a vertical-power DMOSFET and planar MOS IC devices is performed by the newly developed junction-isolation technique using only one epitaxial growth. The isolation voltage of 80 V has been obtained, which is large enough for automotive IPDs if they are protected against high voltage transients on the battery line. A rugged vertical DMOSFET (VDMOS) has also been developed for this IPD. It has a cellular Zener diode between its source and drain, which prevents the secondary breakdown of parasitic bipolar transistor, and the resulting avalanche capability enhancement is more than an order of magnitude. This VDMOS is used for both output power device and protection device for low-voltage MOS circuitry, which makes the IPD free from any transients in the automobile without the need for external protection     

Stirring and its effect on aluminum deoxidation of steel in the ASEA-SKF furnace: Part I. Plant scale measurements and preliminary analysis

Simultaneous radioactive tracer dispersion and deoxidation measurements were taken in a 50 ton, electromagnetically stirred ASEA-SKF furnace. The tracer mixing studies were interpreted in terms of a one-dimensional dispersion model, by the “peak area method” and by the observation of the mixing time. The deoxidation measurements were interpreted by deducing the “deoxidation constant.” The measured eddy diffusivities ranged from about 100 to 300 cm²/s. and the circulation rates were of the order of 50 to 150 tons/min. The measurements indicate that the mixing characteristics of the system are not very much affected by power input (within the range studied), but the actual orientation of the electromagnetic field plays a major role. No direct correlation has been found between the rate of mixing and the deoxidation rate. It is suggested that a more sophisticated interpretation of the results through the use of turbulence theory would provide the desired relationship between mixing and deoxidation. Such work is in progress.     

Comparison of Antifungal and Antioxidant Activities of <Emphasis Type="Italic">Acacia mangium</Emphasis> and <Emphasis Type="Italic">A. auriculiformis</Emphasis> Heartwood Extracts

The effect of heartwood extracts from Acacia mangium (heartrot-susceptible) and A. auriculiformis (heartrot-resistant) was examined on the growth of wood rotting fungi with in vitro assays. A. auriculiformis heartwood extracts had higher antifungal activity than A. mangium. The compounds 3,4,7,8-tetrahydroxyflavanone and teracacidin (the most abundant flavonoids in both species) showed antifungal activity. A. auriculiformis contained higher levels of these flavonoids (3.5- and 43-fold higher, respectively) than A. mangium. This suggests that higher levels of these compounds may contribute to heartrot resistance. Furthermore, both flavonoids had strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and laccase inhibition. This suggests that the antifungal mechanism of these compounds may involve inhibition of fungal growth by quenching of free radicals produced by the extracellular fungal enzyme laccase.