462 research outputs found

    Concrete substrate moisture requirements for durable concrete repairs – a field study

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    peer reviewedIn concrete repair specifications, the required moisture condition of the substrate, which can play an important role for bond development, and, ultimately, on the long-term repair / overlay durability, is generally ill-defined and addressed without due consideration to the given substrate characteristics. The standard specification, if any, is to require saturated surface dry (SSD) condition of the substrate prior to application of cementitious repair materials, which is theoretically achieved after saturating the substrate and then letting the surface just start to dry out. This does provide an intuitive solution founded on rational considerations, but it has never really been precisely defined, measured, nor validated. The influence of substrate surface moisture on the bond between the existing concrete and the new repair material is an issue of significant importance. This paper revisits the question, in light of results from a project designed to develop guidelines for moisture conditioning of a concrete substrate prior to a cementitious repair, which was part of a larger effort to develop guidelines for surface preparation of concrete prior to repair. Over the course of the project, multiple series of test slabs were repaired after being subjected to different surface moisture conditioning and then tested for bond strength tests at different ages. The findings are discussed, together with those from previous studies, and recommendations are issued.9. Industry, innovation and infrastructur

    Exploring the components, asymmetry and distribution of relationship quality in wild Barbary macaques (Macaca sylvanus)

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    Social relationships between group members are a key feature of many animal societies. The quality of social relationships has been described by three main components: value, compatibility and security, based on the benefits, tenure and stability of social exchanges. We aimed to analyse whether this three component structure could be used to describe the quality of social relationships in wild Barbary macaques (Macaca sylvanus). Moreover, we examined whether relationship quality was affected by the sex, age and rank differences between social partners, and investigated the asymmetric nature of social relationships. We collected over 1,900 hours of focal data on seven behavioural variables measuring relationship quality, and used principal component analysis to investigate how these variables clustered together. We found that relationship quality in wild Barbary macaques can be described by a three component structure that represents the value, compatibility and security of a relationship. Female-female dyads had more valuable relationships and same-age dyads more compatible relationships than any other dyad. Rank difference had no effect on the quality of a social relationship. Finally, we found a high degree of asymmetry in how members of a dyad exchange social behaviour. We argue that the asymmetry of social relationships should be taken into account when exploring the pattern and function of social behaviour in animal societies

    Tips for profitable small grain production

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    1 online resource (PDF, 4 pages)This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

    Sodium/myo-Inositol Transporters: Substrate Transport Requirements and Regional Brain Expression in the TgCRND8 Mouse Model of Amyloid Pathology

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    Inositol stereoisomers, myo- and scyllo-inositol, are known to enter the brain and are significantly elevated following oral administration. Elevations in brain inositol levels occur across a concentration gradient as a result of active transport from the periphery. There are two sodium/myo-inositol transporters (SMIT1, SMIT2) that may be responsible for regulating brain inositol levels. The goals of this study were to determine the effects of aging and Alzheimer's disease (AD)-like amyloid pathology on transporter expression, to compare regional expression and to analyze substrate requirements of the inositol transporters. QPCR was used to examine expression of the two transporters in the cortex, hippocampus and cerebellum of TgCRND8 mice, a mouse model of amyloid pathology, in comparison to non-transgenic littermates. In addition, we examined the structural features of inositol required for active transport, utilizing a cell-based competitive uptake assay. Disease pathology did not alter transporter expression in the cortex or hippocampus (p>0.005), with only minimal effects of aging observed in the cerebellum (SMIT1: F2,26 = 12.62; p = 0.0002; SMIT2: F2,26 = 8.71; p = 0.0015). Overall, brain SMIT1 levels were higher than SMIT2, however, regional differences were observed. For SMIT1, at 4 and 6 months cerebellar SMIT1 levels were significantly higher than cortical and hippocampal levels (p<0.05). For SMIT2, at all three ages both cortical and cerebellar SMIT2 levels were significantly higher than hippocampal levels (p<0.05) and at 4 and 6 months of age, cerebellar SMIT2 levels were also significantly higher than cortical levels (p<0.05). Inositol transporter levels are stably expressed as a function of age, and expression is unaltered with disease pathology in the TgCRND8 mouse. Given the fact that scyllo-inositol is currently in clinical trials for the treatment of AD, the stable expression of inositol transporters regardless of disease pathology is an important finding

    The role of pro- and anti-inflammatory responses in silica-induced lung fibrosis

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    BACKGROUND: It has been generally well accepted that chronic inflammation is a necessary component of lung fibrosis but this concept has recently been challenged. METHODS: Using biochemical, histological, immunohistochemistry, and cellular analyses, we compared the lung responses (inflammation and fibrosis) to fibrogenic silica particles (2.5 and 25 mg/g lung) in Sprague-Dawley rats and NMRI mice. RESULTS: Rats treated with silica particles developed chronic and progressive inflammation accompanied by an overproduction of TNF-α as well as an intense lung fibrosis. Dexamethasone or pioglitazone limited the amplitude of the lung fibrotic reaction to silica in rats, supporting the paradigm that inflammation drives lung fibrosis. In striking contrast, in mice, silica induced only a limited and transient inflammation without TNF-α overproduction. However, mice developed lung fibrosis of a similar intensity than rats. The fibrotic response in mice was accompanied by a high expression of the anti-inflammatory and fibrotic cytokine IL-10 by silica-activated lung macrophages. In mice, IL-10 was induced only by fibrotic particles and significantly expressed in the lung of silica-sensitive but not silica-resistant strains of mice. Anti-inflammatory treatments did not control lung fibrosis in mice. CONCLUSION: These results indicate that, beside chronic lung inflammation, a pronounced anti-inflammatory reaction may also contribute to the extension of silica-induced lung fibrosis and represents an alternative pathway leading to lung fibrosis

    Neither loss of Bik alone, nor combined loss of Bik and Noxa, accelerate murine lymphoma development or render lymphoma cells resistant to DNA damaging drugs

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    The pro-apoptotic BH3-only protein, BIK, is widely expressed and although many critical functions in developmental or stress-induced death have been ascribed to this protein, mice lacking Bik display no overt abnormalities. It has been postulated that Bik can serve as a tumour suppressor, on the basis that its deficiency and loss of apoptotic function have been reported in many human cancers, including lymphoid malignancies. Evasion of apoptosis is a major factor contributing to c-Myc-induced tumour development, but despite this, we found that Bik deficiency did not accelerate Eμ-Myc-induced lymphomagenesis. Co-operation between BIK and NOXA, another BH3-only protein, has been previously described, and was attributed to their complementary binding specificities to distinct subsets of pro-survival BCL-2 family proteins. Nevertheless, combined deficiency of Bik and Noxa did not alter the onset of Eμ-Myc transgene induced lymphoma development. Moreover, although p53-mediated induction of Bik has been reported, neither Eμ-Myc/Bik−/− nor Eμ-Myc/Bik−/−Noxa−/− lymphomas were more resistant than control Eμ-Myc lymphomas to killing by DNA damaging drugs, either in vitro or in vivo. These results suggest that Bik, even in combination with Noxa, is not a potent suppressor of c-Myc-driven tumourigenesis or critical for chemotherapeutic drug-induced killing of Myc-driven tumours

    Optimizing the two-step floating catchment area method for measuring spatial accessibility to medical clinics in Montreal

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    <p>Abstract</p> <p>Background</p> <p>Reducing spatial access disparities to healthcare services is a growing priority for healthcare planners especially among developed countries with aging populations. There is thus a pressing need to determine which populations do not enjoy access to healthcare, yet efforts to quantify such disparities in spatial accessibility have been hampered by a lack of satisfactory measurements and methods. This study compares an optimised and the conventional version of the two-step floating catchment area (2SFCA) method to assess spatial accessibility to medical clinics in Montreal.</p> <p>Methods</p> <p>We first computed catchments around existing medical clinics of Montreal Island based on the shortest network distance. Population nested in dissemination areas were used to determine potential users of a given medical clinic. To optimize the method, medical clinics (supply) were weighted by the number of physicians working in each clinic, while the previous year's medical clinic users were computed by ten years age group was used as weighting coefficient for potential users of each medical clinic (demand).</p> <p>Results</p> <p>The spatial accessibility score (SA) increased considerably with the optimisation method. Within a distance of 1 Km, for instance, the maximum clinic accessible for 1,000 persons is 2.4 when the conventional method is used, compared with 27.7 for the optimized method. The t-test indicates a significant difference between the conventional and the optimized 2SFCA methods. Also, results of the differences between the two methods reveal a clustering of residuals when distance increases. In other words, a low threshold would be associated with a lack of precision.</p> <p>Conclusion</p> <p>Results of this study suggest that a greater effort must be made ameliorate spatial accessibility to medical clinics in Montreal. To ensure that health resources are allocated in the interest of the population, health planners and the government should consider a strategy in the sitting of future clinics which would provide spatial access to the greatest number of people.</p
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