Processing map for hot working of alpha-zirconium

The hot deformation characteristics of alpha-zirconium in the temperature range of 650°C to 850°C and in the strain-rate range of 10-3 to 102 s-1 are studied with the help of a power dissipation map developed on the basis of the Dynamic Materials Model. The processing map describes the variation of the efficiency of power dissipation (η=2m/m + 1) calculated on the basis of the strain-rate sensitivity parameter (m), which partitions power dissipation between thermal and microstructural means. The processing map reveals a domain of dynamic recrystallization in the range of 730°C to 850°C and 10-2 to 1-1 with its peak efficiency of 40 pct at 800°C and 0.1 s-1 which may be considered as optimum hot-working parameters. The characteristics of dynamic recrystallization are similar to those of static recrystallization regarding the sigmoidal variation of grain size (or hardness) with temperature, although the dynamic recrystallization temperature is much higher. When deformed at 650°C and 10-3 s-1 texture-induced dynamic recovery occurred, while at strain rates higher than 1 s-1, alpha-zirconium exhibits microstructural instabilities in the form of localized shear bands which are to be avoided in processing

A novel role for syndecan-3 in angiogenesis.

Syndecan-3 is one of the four members of the syndecan family of heparan sulphate proteoglycans and has been shown to interact with numerous growth factors via its heparan sulphate chains. The extracellular core proteins of syndecan-1,-2 and -4 all possess adhesion regulatory motifs and we hypothesized that syndecan-3 may also possess such characteristics. Here we show that a bacterially expressed GST fusion protein consisting of the entire mature syndecan-3 ectodomain has anti-angiogenic properties and acts via modulating endothelial cell migration. This work identifies syndecan-3 as a possible therapeutic target for anti-angiogenic therapy.This work was funded by Arthritis Research-UK (Grant No. 19207) and funds from the William Harvey Research Foundation both to JRW

Specific Syndecan-1 Domains Regulate Mesenchymal Tumor Cell Adhesion, Motility and Migration

Malignant mesothelioma is an asbestos induced cancer that is difficult to diagnose. Several studies have combined biomarkers to improve mesothelioma diagnosis, but with moderate success, and there is a need for new mesothelioma biomarkers. The tumour is often resistant to treatment and most patients will survive less than a year. An indicator of patient survival is the tumours growth pattern, which in turn is influenced by expressed proteoglycans. In this thesis work, we aim to improve the possibilities to diagnose malignant mesothelioma by combining biomarkers and by identifying new ones. We also investigate tumour driving mechanisms with focus on one of these suggested biomarkers, the cell-bound proteoglycan syndecan-1. We were able to construct a diagnostic two-step model based on biomarkers in patient material. By implementing a cut-off level and thereafter focusing on unresolved patients we combined hyaluronan and N-ERC/mesothelin (paper I), which significantly increased the diagnostic accuracy for malignant mesothelioma. To further improve diagnosis, we used mass spectrometry to find new biomarkers. We identified and validated galectin-1, which was excellent in discriminating mesotheliomas from adenocarcinomas (paper II). In the same study, we were also the first to describe aldo-keto reductase 1B10 as a novel prognostic mesothelioma biomarker. Syndecan-1 has been indicated as a marker for carcinomas. In paper I we describe how higher levels of syndecan-1 indicate the presence of a carcinoma over a mesothelioma. This was verified in paper II when syndecan-1 was identified as downregulated in fluids from mesothelioma patients compared to lung cancer patients. Paper III and paper IV focus on this proteoglycan. Malignant cell lines transfected with syndecan-1 and various truncated forms of syndecan-1 affected adhesion and migration, which are key features of cancer invasion (paper III). The results showed a domain- and cell type specific effect on the cells’ motility. Regulating syndecan-1 levels and analysing the global gene expression of mesothelioma cells made it evident that this proteoglycan has a strong influence on transforming growth factor β signalling and several growth factor pathways (paper IV). Links to cell migration and proliferation were furthermore identified, along with glycosaminoglycan modifying enzymes. These results can shed light on the complex role of syndecan-1 in invasion and growth of malignant mesenchymal cells. Taken together, this thesis work describes a complement to conventional mesothelioma diagnosis and identifies novel biomarkers. Furthermore, the potential biomarker syndecan-1 was shown to have an effect on cell motility and proliferation. These results increase our understanding of this aggressive malignancy

Ionization cross sections in He, Ne, A, Kr and Xe by electron impact

Measurements of the total ionization cross sections for the rare gases helium, neon, argon, krypton mid xenon under electron impact extending over the electron energy range up to 100 ev have been made with a Tate and Smith apparatus and a Lozier type apparatus. The two sets of measurements show close agreement with one another in the entire electron energy range; however, some deviation from earlier data is observed. The first ionization potentials were determined using tin absolute method for the electron energy calibration, and the agreement with the spectroscopic values is within the error in the electron energy mensurement, which is ±0.08 ov

Amplitude dependent internal friction under torsion

The Granato-Lucke expression for the strain amplitude dependent damping capacity due to stress induced unpinning of dislocation, is modified for the case of torsion. The final expression is in the form of an integral which can be evaluated only numerically. A differential equation and an integral equation involving the mean damping capacity and the maximum strain amplitude have been derived, which enable straight line plots and evaluation of the G-L parameters from them. With suitable examples it has been shown that the pinning point density is exaggerated by a factor of 1.3 when uniform strain amplitude is assumed. Numerical evaluation of the integral has been made using Simpson's Rule for different ε0. Plots of the mean damping capacity \-gD and \-gD/ε0n vs ε0, have been made for different n values; all of which show maxima. It has been shown that the G-L parameters can be calculated from the positions of the maxima

Electron microscopy of oxide films on Zircaloy-2

172-176<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">Initial oxide films formed on ZircaIoy-2 in steam at 750oC for periods of 10 and 20 s have been studied using transmission electron microscopy. The initial. Oxide film is seen to be amorphous but rapidly starts crystallizing during examination. The crystallization product is a mixture of tetragonal and monoclinic oxides. The film obtained at 750oC after 20 s of oxidation is fully crystalline and is in the cubic phase of oxide. Delineation of substrate grains in this case is clearly seen. The formation of metastable phases of the oxide has been explained. The orientation relationship between the metal and the oxide has been determined.</span

Revised Franck-Condon factors for the ionization transition of O<SUB>2</SUB> and the second negative band system of O<SUP>+</SUP><SUB>2</SUB>

Franck-Condon factors are calculated for the ionization transition of O<SUB>2</SUB> and the second negative bands of O<SUP>+</SUP><SUB>2</SUB> using revised molecular constants for the ground state of O<SUP>+</SUP><SUB>2</SUB>. The potential functions of the various states considered are constructed by the RKR method using an exact technique presented by Zeleznik

The calibration of the electron energy scale for ionization potential measurements

The theoretically evaluated electron energy distribution curve from a function of the type U exp ( - U/kT), as given by Fowler and Honig, for electrons emitted from a heated filament is compared with the experimentally determined curve. The shift in the maxima of the experimental curve as compared with the theoretical one is attributed to the contact potential in the system, and consequently this shift has been used as a means of evaluating the contact potential during the course of an experiment. The shape of the ionization efficiency curve is analysed and the linearly extrapolated value is shown to be lower than the true ionization potential by 2 kT when the ionizing electrons have a distribution corresponding to the above mentioned function. Finally the experimentally determined contact potential and the value 2 kT evaluated corresponding to the filament temperature are used to obtain the ionization potentials in four gases on an absolute scale to within &#177;0.08 ev. The results are compared with spectroscopic data