A radium assay technique using hydrous titanium oxide adsorbent for the Sudbury Neutrino Observatory

As photodisintegration of deuterons mimics the disintegration of deuterons by neutrinos, the accurate measurement of the radioactivity from thorium and uranium decay chains in the heavy water in the Sudbury Neutrino Observatory (SNO) is essential for the determination of the total solar neutrino flux. A radium assay technique of the required sensitivity is described that uses hydrous titanium oxide adsorbent on a filtration membrane together with a beta-alpha delayed coincidence counting system. For a 200 tonne assay the detection limit for 232Th is a concentration of 3 x 10^(-16) g Th/g water and for 238U of 3 x 10^(-16) g U/g water. Results of assays of both the heavy and light water carried out during the first two years of data collection of SNO are presented.Comment: 12 pages, 4 figure

Matching the nano- to the meso-scale: measuring deposit–surface interactions with atomic force microscopy and micromanipulation

Many researchers have studied the effects of changing the surface on fouling and cleaning. In biofouling the 'Baier curve' is a well-known result which relates adhesion to surface energy, and papers on the effect of changing surface energy to food fouling can be found more than 40 years ago. Recently the use of modified surfaces, at least at a research level, has been widespread. Here two different ways of studying surface-deposit interactions have been compared. Atomic force microscopy (AFM) is a method for probing interactions at a molecular level, and can measure (for example) the interaction between substrate and surfaces at a nm-scale. At a μm-mm level, we have developed a micromanipulation tool that can measure the force required to remove the deposit; the measure incorporates both surface and bulk deformation effects. The two methods have been compared by studying a range of model soils: toothpaste, as an example of a soil that can be removed by fluid flow alone, and confectionery soils. Removal has been studied from glass, stainless steel and fluorinated surfaces as examples of the sort of surfaces that can be found in practice. AFM measurements were made by using functionalized tips in force mode. The two types of probe give similar results, although the rheology of the soil affects the measurement from the micromanipulation probe under some circumstances. The data suggests that either method could be used to test candidate surfaces

Intoxicação por Senecio spp. em bovinos no Rio Grande do Sul: condições ambientais favoráveis e medidas de controle

Este trabalho teve por objetivo revisar os principais aspectos da intoxicação por Senecio spp. no Rio Grande do Sul no que se refere à patologia, patogenia e epidemiologia dessa importante causa de morte em bovinos nesse Estado. Foram abordados, também, os principais fatores climáticos e ambientais que aparentemente favorecem a emergência e o estabelecimento da planta e a ocorrência da intoxicação, que tem aumentado a sua frequência nos últimos anos no Estado, e as possíveis formas de controle da planta incluindo o manejo correto do solo e a utilização de espécies domésticas menos susceptíveis nas áreas invadidas

Lesions of Experimental Equine Morbillivirus Pneumonia in Horses

Laboratory examinations of equine morbillivirus included experimental reproductions of the disease caused by the virus by transmission of mixed lung and spleen taken from two field equine cases into two horses and by inoculating tissue culture virus into a further two horses. The most distinctive gross lesions of the diseases that developed in three of the horses was that of pulmonary edema characterized by gelatinous distension of subpleural lymphatics. Histologically, the lesions in the lungs were those of serofibrinous alveolar edema, alveolar macrophages, hemorrhage, thrombosis of capillaries, and syncytial cells. Clearly defined vascular lesions in three horses that became clinically affected within 8 days of inoculation of virus included intramural hemorrhage, edema, and necrosis and syncytial cells in the endothelium of pulmonary vessels (∼40-70 μm in diameter). Vascular lesions accompanied by parenchymal degeneration were also seen in the heart, kidney, brain, spleen, lymph node, and stomach. A fourth horse, which survived for 12 days, had detectable lesions only in the lungs, which were more chronic than those in the other three horses, a greater degree of cellular infiltration, and fewer well-defined vascular lesions. Sections stained by an indirect immunocytochemical method showed equine morbillivirus antigen was present in the vascular lesions and along alveolar walls. When endothelial cells were examined by electron microscope, cytoplasmic virus inclusion bodies containing filamentous structures were seen that reacted to an immunogold test to equine morbillivirus antigen. The presence of the syncytia in the small blood vessels in the lungs and other organs was interpreted as an important characteristic of the disease and consistent with a reaction to a morbillivirus

Histopathology and immunohistochemistry of bats infected by Australian bat lyssavirus

Objective: To describe the lesions and distribution of viral antigens in bats infected by Australian bat lyssavirus. Design: A retrospective histopathological and immunohistochemical study of bats naturally infected with the virus. Procedure: Tissues from 37 infected bats were examined. Nineteen flying foxes (fruit bats) and two insectivorous bats were examined in detail. Brains of another 16 flying foxes were poorly fixed and were examined less fully. Result: Lesions varied considerably between individuals and, where present, were mostly those of nonsuppurative meningoencephalomyelitis and ganglioneuritis similar to lesions seen in rabies and rabies-like diseases. The number of cells with intracytoplasmic inclusion bodies (Negri bodies) was variable; none were seen in some bats. Intracytoplasmic vacuolation of neurons was a common finding. Lesions occurred throughout the central nervous system but were most frequent and severe in the hippocampus, thalamus and midbrain, and medulla oblongata and pons. Indirect immunoperoxidase tests for lyssavirus antigen reactions varied in intensity and distribution, but also occurred mostly in the hippocampus, thalamus and midbrain, and medulla oblongata and pons. In peripheral tissues, reactions were seen in autonomic ganglia, in nerve plexuses of the gastrointestinal tract, in nervous tissues within muscles and immediately adjacent to individual muscle fibres, in an adrenal medulla, and in epithelial tissues in one of eight salivary glands examined. Conclusion: The main lesion in Australian bat lyssavirus infection is nonsuppurative inflammation similar to that seen in rabies and other rabies-like diseases, except that the number of Negri bodies is more variable. Reactions to immunoperoxidase tests for lyssavirus vary in intensity and distribution and may occur in both central and peripheral nervous systems. These reactions do not always occur in the salivary glands, even if brain infection is present