Osteochondrodysplasia occurring in transgenic mice expressing interferon-gamma

Arterial thrombi are primarily composed of platelets. Platelets are bound to injured endothelial cells, sub-endothelial matrices, and other platelets by a range of adhesive proteins. Some of these reactions are governed by shear forces. The role of adhesive proteins in the pathogenesis of arterial thrombosis is not fully understood. The aim of this study was to examine the involvement of von Willebrand factor (vWF), fibrinogen (Fg), and fibronectin (FN) in the formation of microvascular thrombi in vivo using a helium-neon laser-induced thrombosis method. Transmission electron microscopy demonstrated that laser irradiation resulted in platelet-rich thrombosis in arterioles and venules, and revealed that this occurred in the absence of endothelial denudation. The mean wall shear rates in mesenteric arterioles and venules were 641 +/- 40 and 280 +/- 20 s-1, respectively. Shear rates increased approximately fivefold in arterioles and tenfold in venules during the formation of occlusive thrombi. Antibody to vWF inhibited thrombosis in arterioles and venules. Antibodies to Fg and FN inhibited thrombosis in venules but not in arterioles. These results confirm that vWF, Fg and FN were involved in thrombogenesis in vivo and demonstrated that significantly higher shear rates were required for the reactions involving vWF than those involving either Fg or FN.     

Immunocytochemical localization of dopamine and its synthetic enzymes in the central nervous system of the lamprey Lampetra fluviatilis

The distribution of dopamine (DA)-containing cell bodies, fibers, and terminals in the brain and spinal cord of Lampetra fluviatilis was investigated by immunohistochemical means. In order to distinguish dopaminergic neurons from those using other catecholamines as the primary neurotransmitter, the distribution of dopamine-immunoreactive structures was compared to that of cell bodies, fibers, and terminals labelled with antibodies directed against the enzymes tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), dopamine beta-hydroxylase (DBH), and phenylethanolamine-N-methyl transferase (PNMT). We define dopaminergic neurons as those that are simultaneously DA, TH, and AADC immunoreactive and at the same time DBH and PNMT nonreactive. The overall concentrations of dopamine, noradrenaline, and adrenaline and some of their metabolites were also measured via high-performance liquid chromatography of whole-brain extracts. Our results revealed the presence of 10 populations of dopaminergic neurons in the brain of the lamprey in the olfactory bulb, preoptic area, hypothalamus, rhombencephalon, and spinal cord. In addition, uniquely DA-immunoreactive neurons, in contact with the cerebrospinal fluid, were observed in the hypothalamus and spinal cord. Chromatography indicated that dopamine exists in considerably higher concentrations than noradrenaline in the lamprey brain, whereas adrenaline is absent, the latter finding being supported by our failure to observe any PNMT-immunoreactive cell bodies, fibers, or terminals. The dopaminergic system of the lamprey appears to share many features not only with that of other anamniotes but also with that of amniotes; however, as in teleosts, dopaminergic neurons in the midbrain corresponding to the substantia nigra, the retrorubral area, and the ventral tegmental area of other species do not exist in the lamprey.     

Effect of molecular weight on the morphology and drawing behaviour of melt crystallized linear polyethylene

The effect of molecular weight on the cold drawing behaviour of melt crystallized linear polyethylene has been studied. It is shown that the draw ratio achieved under comparable conditions rises with decreasing $\text{M}\text{?}{}_{\mathrm{w}}$, very high draw ratios (～36) being possible for optimum morphology of the undrawn polymer. The yield behaviour was also examined, and it is shown that the yield stress is affected in a complex fashion by both crystallization conditions and molecular weight. These results are discussed in terms of the crystallization and morphology of the melt crystallized polymer.     

A novel technique for measuring the impact properties of a tough polyethylene

A novel technique is described which enables reliable fracture toughness measurements to be made in impact test on relatively small specimens of a tough polyethylene. Composite specimens have been made in which a tough polyethylene is sandwiched between two layers of a more brittle polyethylene. The overall fracture toughness is interpreted on the basis of simple additivity of the strain energy release rate associated with each of the component layers. Brittle plane strain failures were obtained for specimens in which the relative thickness of the layers was varied over a substantial range and the fracture toughness of each layer determined by suitable extrapolation. The fracture toughness of the brittle layer obtained in this way agreed well with direct measurements on that material.     

Identification of important image features for pork and turkey ham classification using colour and wavelet texture features and genetic selection

A method to discriminate between various grades of pork and turkey ham was developed using colour and wavelet texture features. Image analysis methods originally developed for predicting the palatability of beef were applied to rapidly identify the ham grade. With high quality digital images of 50–94 slices per ham it was possible to identify the greyscale that best expressed the differences between the various ham grades. The best 10 discriminating image features were then found with a genetic algorithm. Using the best 10 image features, simple linear discriminant analysis models produced 100% correct classifications for both pork and turkey on both calibration and validation sets.     

The hot compaction behaviour of woven oriented polypropylene fibres and tapes. I. Mechanical properties

The aim of this work was to establish the important parameters that control the hot compaction behaviour of woven oriented polypropylene. Five commercial woven cloths, based on four different polypropylene polymers, were selected so that the perceived important variables could be studied. These include the mechanical properties of the original oriented tapes or fibres, the geometry of the oriented reinforcement (fibres or tapes), the mechanical properties of the base polymer (which are crucially dependant on the molecular weight and morphology), and the weave style. The five cloths were chosen so as to explore the boundaries of these various parameters, i.e. low and high molecular weight: circular or rectangular reinforcement (fibres or tapes): low or high tape initial orientation: coarse or fine weave.A vital aspect of this study was the realisation that hot compacted polypropylene could be envisaged as a composite, comprising an oriented ‘reinforcement’ bound together by a matrix phase, formed by melting and recrystallisation of the original oriented material. We have established the crucial importance of the properties of the melted and recrystallised matrix phase, especially the level of ductility, in controlling the properties of the hot compacted composite.     

Effect of molecular weight and branch content on the creep behavior of oriented polyethylene

Creep studies were carried out on a range of homopolymers and copolymers of polyethylene with well‐defined molecular weight and branch content. The creep data were analyzed in terms of two thermally activated processes acting in parallel and the effects of molecular weight and branch content are discussed. It is shown that increasing either the number‐average molecular weight or the weight‐average molecular weight gives improved creep behavior at all stress levels. The introduction of butyl branches leads to lower creep at low‐stress levels but can give rise to higher creep at high stress. Plots of the equilibrium log₁₀(strain rate) versus stress at fixed draw ratio (strain) can be used to define sections through a unique true stress/true strain/strain rate surface for each material. These creep results have an additional value in terms of the link between slow crack propagation (SCG) in polyethylene and fibril creep, confirming the proposal made elsewhere that SCG can be quantified in terms of creep to failure across the true stress/true strain/strain rate surface. © 2003 Wiley Periodicals, J Appl Polym Sci 89: 1663–1670, 2003     

Synthesis and Evaluation of Water‐Soluble Prodrugs of Ursodeoxycholic Acid (UDCA), an Anti‐apoptotic Bile Acid

Ursodeoxycholic acid (UDCA) is a bile acid with demonstrated anti‐apoptotic activity in both in vitro and in vivo models. However, its utility is hampered by limited aqueous solubility. As such, water‐soluble prodrugs of UDCA could have an advantage over the parent bile acid in indications where intravenous administration might be preferable, such as decreasing damage from stroke or acute kidney injury. Five phosphate prodrugs were synthesized, including one incorporating a novel phosphoryloxymethyl carboxylate (POMC) moiety. These prodrugs were highly water‐soluble, but showed significant differences in chemical stability, with oxymethylphosphate prodrugs being the most unstable. In a series of NMR experiments, the POMC prodrug was bioactivated to UDCA by alkaline phosphatase (AP) faster than a prodrug containing a phosphate directly attached to the alcohol at the 3‐position of UDCA. Both of these prodrugs showed significant anti‐apoptotic activity in a series of in vitro assays, although the POMC prodrug required the addition of AP for activity, while the other compound was active without exogenous AP.     

Relationship Between Structure and Coordination Strength of N and N,O-Hybrid Donor Ligands with Trivalent Lanthanides

ABSTRACT

To effectively separate lanthanides (Ln(III)) from actinides (An(III)), symmetrical 2,2′-bipyridyl (Bpy), 1,10-phenanthroline (Phen), and unsymmetrical N-methyl-N-tolyl-1,10-phenanthroline-2-carboxamide (MeTol-PTA) were investigated. According to the crystal structures and EXAFS experiments, the decreasing ionic radius from light to heavy Ln led to decreases in the Ln–N (Bpy) and Ln–N (Phen) distances, while log β simply increased due to the electrostatic interaction and the order of Ln–O (MeTol-PTA) < Ln–N (Bpy, Phen) < Ln–N (MeTol-PTA) was obtained. This indicated that the bulky phenanthroline moiety of MeTol-PTA may not allow N (MeTol-PTA) to come close to Ln. Consequently, the log β of MeTol-PTA exhibited a local maximum (around Nd).