Preparation of Cu-based bulk metallic glasses by suction casting

A series of Cu-Hf-Ti alloys prepared by rapid solidification of the melt and by copper mould casting were studied in the present work. Alloy ingots were prepared by arc-melting mixtures of pure metals in an argon atmosphere. An indication of the cooling rate obtained was determined using an Al-4.5 wt%Cu alloy. Cooling rates varied from 540 K/s for the centre section of a 4 mm die to 885 K/s for the outside wall section of the 2 mm die. The glass-forming ability, structure and thermal stability of Cu-Hf-Ti glassy alloys were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Bulk glass formation was observed for the Cu64Hf36, Cu55Hf25Ti20 and Cu56Hf25Ti19 alloys, with critical diameters dc for a fully glassy structure of 1, 4 and 5 mm, respectively. The substitution of Hf by Ti increased the glassforming ability (GFA) and the thermal stability

Field Application of a Monoclonal Antibody Panel to Differentiate Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Isolates

Porcine reproductive and respiratory syndrome (PRRS) is recognized as the most economically devastating disease of swine throughout the world. Nucleotide sequencing and serological studies have deomnstrated sustantial antigenic variation amoung PRRS virus (PRRSV) isolates (Murtaugh, et al., 1995; Nelson, et al., 1993, 1996). Recently, European-like PRRSV isolates have been identified in the US (Rossow, et al. 2000) and other new, highly virulent PRRSV isolates have appeared and affect sows at all stages of gestation causing mortality of adult pigs as well as young pigs (Epperson et al., 1997). Therefore, it is even more important to control the spread of these new strains. Clinical signs vary between herds, indicating that viruses may differ in pathogenicity. Furthermore, effective use of vaccines and management approaches to control PRRS has not always been successful

Simulating pathways of subsurface oil in the Faroe–Shetland Channel using an ocean general circulation model

Little is known about the fate of subsurface hydrocarbon plumes from deep-sea oil well blowouts and their effects on processes and communities. As deepwater drilling expands in the Faroe–Shetland Channel (FSC), oil well blowouts are a possibility, and the unusual ocean circulation of this region presents challenges to understanding possible subsurface oil pathways in the event of a spill. Here, an ocean general circulation model was used with a particle tracking algorithm to assess temporal variability of the oil-plume distribution from a deep-sea oil well blowout in the FSC. The drift of particles was first tracked for one year following release. Then, ambient model temperatures were used to simulate temperature-mediated biodegradation, truncating the trajectories of particles accordingly. Release depth of the modeled subsurface plumes affected both their direction of transport and distance travelled from their release location, and there was considerable interannual variability in transport

High resolution study of the spatial distributions of abyssal fishes by autonomous underwater vehicle

On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850?m water depth) encompassing two spatial scales (1–10?km2) on and adjacent to a small abyssal hill (240?m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km?2 (95% CI: 601–844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km?2 respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed

Single and multigland disease in primary hyperparathyroidism: Clinical follow-up, histopathology, and flow cytometric DNA analysis

Two-hundred seventy-four patients with primary hyperparathyroidism had selective removal of enlarged parathyroid glands. Biopsies were taken from all parathyroid glands. Normal-size glands were not resected irrespective of their histological appearance. After a mean follow-up of 13.5 years the rates of persistent and recurrent hyperparathyroidism were, respectively, 3.6% and 0.7%. Transient and permanent hypoparathyroidism occurred in 24% and 2.5% of the patients. The microscopic appearance of enlarged glands and of biopsies taken from normal-size glands were reviewed by two pathologists. Normal parathyroid glands were distinguished from abnormal glands fairly accurately (sensitivity 93%, specificity 80%). Microscopic classification of abnormal parathyroid glands as adenomas or hyperplastic glands correlated poorly with the gross classification as single or multigland disease. Flow cytometric DNA analysis of paraffin embedded parathyroid tissue showed significant differences for DNA index, % S-phase and % G2M (p<0.001). Differentiating single from multigland disease by means of DNA analysis was not possible. In conclusion, removal of only enlarged parathyroid glands results in acceptable rates of persistent and recurrent hyperparathyroidism. Biopsies should only be taken sparingly to prevent transient and permanent hypoparathyroidism. Microscopic examination and flow cytometric DNA analysis can differentiate normal from abnormal parathyroid glands but are unable to differentiate abnormal glands into single or multigland disease

A Comparative Study of the Formation of Aromatics in Rich Methane Flames Doped by Unsaturated Compounds

For a better modeling of the importance of the different channels leading to the first aromatic ring, we have compared the structures of laminar rich premixed methane flames doped with several unsaturated hydrocarbons: allene and propyne, because they are precursors of propargyl radicals which are well known as having an important role in forming benzene, 1,3-butadiene to put in evidence a possible production of benzene due to reactions of C4 compounds, and, finally, cyclopentene which is a source of cyclopentadienylmethylene radicals which in turn are expected to easily isomerizes to give benzene. These flames have been stabilized on a burner at a pressure of 6.7 kPa (50 Torr) using argon as dilutant, for equivalence ratios (?) from 1.55 to 1.79. A unique mechanism, including the formation and decomposition of benzene and toluene, has been used to model the oxidation of allene, propyne, 1,3 butadiene and cyclopentene. The main reaction pathways of aromatics formation have been derived from reaction rate and sensitivity analyses and have been compared for the three types of additives. These combined analyses and comparisons can only been performed when a unique mechanism is available for all the studied additives

Display of antigens on polyester inclusions lowers the antigen concentration required for a bovine tuberculosis skin test

The tuberculin skin test is the primary screening test for the diagnosis of bovine tuberculosis (TB), and use of this test has been very valuable in the control of this disease in many countries. However, the test lacks specificity when cattle have been exposed to environmental mycobacteria or vaccinated with Mycobacterium bovis bacille Calmette-Guérin (BCG). Recent studies showed that the use of three or four recombinant mycobacterial proteins, including 6-kDa early secretory antigenic target (ESAT6), 10-kDa culture filtrate protein (CFP10), Rv3615c, and Rv3020c, or a peptide cocktail derived from those proteins, in the skin test greatly enhanced test specificity, with minimal loss of test sensitivity. The proteins are present in members of the pathogenic Mycobacterium tuberculosis complex but are absent in or not expressed by the majority of environmental mycobacteria and the BCG vaccine strain. To produce a low-cost skin test reagent, the proteins were displayed at high density on polyester beads through translational fusion to a polyhydroxyalkanoate synthase that mediates the formation of antigen-displaying inclusions in recombinant Escherichia coli. Display of the proteins on the polyester beads greatly increased their immunogenicity, allowing for the use of very low concentrations of proteins (0.1 to 3 μg of mycobacterial protein/inoculum) in the skin test. Polyester beads simultaneously displaying all four proteins were produced in a single fermentation process. The polyester beads displaying three or four mycobacterial proteins were shown to have high sensitivity for detection of M. bovis-infected cattle and induced minimal responses in animals exposed to environmental mycobacteria or vaccinated with BCG.Full Tex

The spatial scale of ozone depletion events derived from an autonomous surface ozone network in coastal Antarctica

To probe the spatial extent of tropospheric ozone depletion events during Antarctic spring, a network of 10 autonomous ozone monitors was established around the Dronning Maud Land sector of Antarctica for a full calendar year. Together with manned stations in the area, the network covered a ~1200 km stretch of coast, as well as a transect ~300 km inland and to ~2000 m above sea level (a.s.l.). Here we present results from the spring period (August to October 2008). While some ozone depletion events were evident at only a single site, implying localised ozone destruction, others were evident across the network. The fact that, on occasions, ozone depletion events were observed at all coastal sites simultaneously, suggests the depleted air mass had a scale of at least 1200 km. As the ozone-poor air was advected from the Weddell Sea sea ice zone, the data imply that large areas over the Weddell Sea sea ice zone are significantly depleted in ozone on occasions during Antarctic spring