455 research outputs found

    Large Animal Ectoparasite Control

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    Recent rulings by the Food and Drug Administration make it more imperative than ever that practitioners use, sell, and recommend proper insecticides for the control of ectoparasites. Very few of the commonly used insecticides have a tolerance established by the FDA in meat and dairy products

    Making the Court an Open Public Institution

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    3D Raman mapping of the collagen fibril orientation in human osteonal lamellae

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    AbstractChemical composition and fibrillar organization are the major determinants of osteonal bone mechanics. However, prominent methodologies commonly applied to investigate mechanical properties of bone on the micro scale are usually not able to concurrently describe both factors. In this study, we used polarized Raman spectroscopy (PRS) to simultaneously analyze structural and chemical information of collagen fibrils in human osteonal bone in a single experiment. Specifically, the three-dimensional arrangement of collagen fibrils in osteonal lamellae was assessed. By analyzing the anisotropic intensity of the amide I Raman band of collagen as a function of the orientation of the incident laser polarization, different parameters related to the orientation of the collagen fibrils and the degree of alignment of the fibrils were derived. Based on the analysis of several osteons, two major fibrillar organization patterns were identified, one with a monotonic and another with a periodically changing twist direction. These results confirm earlier reported twisted and oscillating plywood arrangements, respectively. Furthermore, indicators of the degree of alignment suggested the presence of disordered collagen within the lamellar organization of the osteon. The results show the versatility of the analytical PRS approach and demonstrate its capability in providing not only compositional, but also 3D structural information in a complex hierarchically structured biological material. The concurrent assessment of chemical and structural features may contribute to a comprehensive characterization of the microstructure of bone and other collagen-based tissues

    Can a continuous mineral foam explain the stiffening of aged bone tissue? A micromechanical approach to mineral fusion in musculoskeletal tissues

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    Recent experimental data revealed a stiffening of aged cortical bone tissue, which could not be explained by common multiscale elastic material models. We explain this data by incorporating the role of mineral fusion via a new hierarchical modeling approach exploiting the asymptotic (periodic) homogenization (AH) technique for three-dimensional linear elastic composites. We quantify for the first time the stiffening that is obtained by considering a fused mineral structure in a softer matrix in comparison with a composite having non-fused cubic mineral inclusions. We integrate the AH approach in the Eshelby-based hierarchical mineralized turkey leg tendon model (Tiburtius et al 2014 Biomech. Model. Mechanobiol. 13 1003–23), which can be considered as a base for musculoskeletal mineralized tissue modeling. We model the finest scale compartments, i.e. the extrafibrillar space and the mineralized collagen fibril, by replacing the self-consistent scheme with our AH approach. This way, we perform a parametric analysis at increasing mineral volume fraction, by varying the amount of mineral that is fusing in the axial and transverse tissue directions in both compartments. Our effective stiffness results are in good agreement with those reported for aged human radius and support the argument that the axial stiffening in aged bone tissue is caused by the formation of a continuous mineral foam. Moreover, the proposed theoretical and computational approach supports the design of biomimetic materials which require an overall composite stiffening without increasing the amount of the reinforcing material

    WCM: A web content‐based method of stakeholder analysis

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    This article presents a systematic method to conduct stakeholder analyses using textual data from stakeholder websites. WCM, a novel web content-based method comprises stakeholder information and the use of keywords in a content analysis of relevant preselected stakeholder websites. Traditional stakeholder analysis approaches frequently rely on personal interpretation rather than empirical analysis. WCM aims to address this limitation by offering a user-friendly and empirical method that helps generate knowledge from multiple websites. With qualitative and / or quantitative application, it is particularly useful for small-scale studies in complex contexts and where resources are limited. WCM differs from many commonly used stakeholder analysis methods as it adopts replicable, systematic and transparent procedures. While not without limitations, this method provides an effective tool to support researchers, non-governmental organizations, and industry in different fields and locations, to undertake stakeholder analysis. • The WCM method is a systematic, explicit, transparent, and transferable procedure to conduct stakeholder analysis. • WCM has application in both qualitative and quantitative content analysis of stakeholder websites. • WCM provides a user-friendly method to provide a broad overview of stakeholder interests with limited resources

    volumetric characterisation and correlation to established classification systems

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    Objective and sensitive assessment of cartilage repair outcomes lacks suitable methods. This study investigated the feasibility of 3D ultrasound biomicroscopy (UBM) to quantify cartilage repair outcomes volumetrically and their correlation with established classification systems. 32 sheep underwent bilateral treatment of a focal cartilage defect. One or two years post- operatively the repair outcomes were assessed and scored macroscopically (Outerbridge, ICRS-CRA), by magnetic resonance imaging (MRI, MOCART), and histopathology (O'Driscoll, ICRS-I and ICRS-II). The UBM data were acquired after MRI and used to reconstruct the shape of the initial cartilage layer, enabling the estimation of the initial cartilage thickness and defect volume as well as volumetric parameters for defect filling, repair tissue, bone loss and bone overgrowth. The quantification of the repair outcomes revealed high variations in the initial thickness of the cartilage layer, indicating the need for cartilage thickness estimation before creating a defect. Furthermore, highly significant correlations were found for the defect filling estimated from UBM to the established classification systems. 3D visualisation of the repair regions showed highly variable morphology within single samples. This raises the question as to whether macroscopic, MRI and histopathological scoring provide sufficient reliability. The biases of the individual methods will be discussed within this context. UBM was shown to be a feasible tool to evaluate cartilage repair outcomes, whereby the most important objective parameter is the defect filling. Translation of UBM into arthroscopic or transcutaneous ultrasound examinations would allow non-destructive and objective follow-up of individual patients and better comparison between the results of clinical trials

    Tree insect pests and pathogens: a global systematic review of their impacts in urban areas

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    Trees contribute greatly to urban environments and human well-being, yet relatively little is known about the extent to which a rising incidence of tree insect pests and pathogens may be affecting these contributions. To address this issue, we undertook a systematic review and synthesis of the diverse global empirical evidence on the impacts of urban tree insect pests and pathogens, using bibliographic databases. Following screening and appraisal of over 3000 articles from a wide range of fields, 100 studies from 28 countries, spanning 1979–2021, were conceptually sorted into a three-part framework: (1) environmental impacts, representing 95 of the studies, including those reporting on tree damage, mortality, reduced growth, and changes in tree function; (2) social impacts were reported by 35 of studies, including on aesthetics, human health, and safety hazards; and (3) economic impacts, reported in 24 of studies, including on costs of pest management, and economic losses. There has been a considerable increase in urban impact studies since 2011. Evidence gaps exist on impacts on climate-regulating capacity, including temperature regulation, water retention, soil erosion, and wind protection, but also on specific hazards, nuisances, human well-being, property damages, and hazard liabilities. As a knowledge synthesis, this article presents the best available evidence of urban tree insect / pathogen impacts to guide policy, management and further research. It will enable us to better forecast how growing threats will affect the urban forest and plan for these eventualities
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