The theoretical formulas of the fluorescent x-ray intensity (the primary, the secondary and the tertiary fluorescent x-rays) are obtained and actual calculations are made for nickel-iron, iron-chromium, and nickel-iron-chromium alloys. In the calculation, the continuous intensity distribution of the irradiating x-rays for the wavelength is taken into account. The theoretical results agree with the experiments very well, the deviations being 1% at most, and it is concluded that the theoretical estimation of the fluorescent x-ray intensity emitted from samples of various composition is possible. The matrix effect, absorption effect, and enhancement effect are evaluated from the present theory. In the enhancement effect, secondary fluorescent x-rays are quite significant (for instance, the chromium secondary fluorescent x-rays from Cr 2% and Fe 98% alloy reach the 55% of the chromium primary fluorescent x-rays and they can not be neglected), but the tertiary fluorescent x-rays are only a few per cent. The usual approximation methods, where the irradiating x-rays are assumed as monochromatic rays and the secondary fluorescent rays are not taken into consideration are also discussed and their meaning is made clear.
Pancreatic cancer is frequently associated with intense growth of fibrous tissue at the periphery of tumours, but the histopathological quantification of this stromal reaction has not yet been used as a prognostic factor because of the difficulty of obtaining quantitative measures using manual methods. Manual histological grading is a poor indicator of outcome in this type of cancer and there is a clinical need to establish a more sensitive indicator. Recent pancreatic tumour biology research has focused upon the stromal reaction and there is an indication that its histopathological quantification may lead to a new prognostic indicator.Histological samples from 21 cases of pancreatic carcinoma were stained using the sirius red, light-green method. Multiple images from the centre and periphery of each tumour were automatically segmented using colour cluster analysis to subdivide each image into representative colours. These were classified manually as stroma, cell cytoplasm or lumen in order to measure the area of each component in each image. Measured areas were analysed to determine whether the technique could detect spatial differences in the area of each tissue component over all samples, and within individual samples.Over all 21 cases, the area of stromal tissue at the periphery of the tumours exceeded that at the centre by an average of 10.0 percentage points (P < 0.001). Within individual tumours, the algorithm was able to detect significantly more stroma (P < 0.05) at the periphery than the centre in 11 cases, whilst none of the remaining cases had significantly more stromal tissue at the centre than the periphery.The results demonstrate that semi-automated analysis can be used to detect spatial differences in the area of fibrous tissue in routinely stained sections of pancreatic cancer.
A solid-state phase transformation in octafluoronaphthalene has been discovered at 266.5 K on cooling, and at 15 K higher on heating. The symmetry of both phases is found to be the same, namely monoclinic with space group P2,/c. The unit cell parameters change by up to 10 x, but the integrity of a single crystal, which shatters on cooling, is good enough for a single-crystal structure determination. This has been done in both phases to a sufficient accuracy that a mechanism for the transformation can be proposed. Molecules which lie parallel to one another shear to a new parallel position, the shear movement being equal to one carbon-carbon bond of the naphthalene skeleton. In this process the molecules reorient. but are still related by the same \ j inmetry operations. This transformation, although not unique, is probably the first of its kind to be discovered in molecular systems.
The scales formed on the steels are examined through the electron probe microanalysis. Examined steels are low carbon rimmed steel, silicon killed steel, weather-resistance steel, high strength steel, sulfer free-cutting steel, ferritic and austenitic stainless steels.
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