260 research outputs found

    Quantification of micro-scale variability in fibre bundles

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    Local variations in the random filament arrangement in carbon fibre bundles were determined by optical microscopy and automated image analysis. Successive steps of abrading, polishing and acquiring micro¬graphs of the sample surface made it feasible to analyse the micro-structure over a series of cross-sections along the fibre bundle path. Random and systematic changes in local filament arrangements were determined. Systematic changes were related to the interaction of a fibre bundle with an intersect¬ing binder thread leading to a local increase of the fibre volume fraction at the interface. Random clus¬tering of filaments in areas of high or low fibre volume fractions within the fibre bundles were found to be unaffected by the relative position of the bundle

    Cancer during Adolescence: Negative and Positive Consequences Reported Three and Four Years after Diagnosis

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    Persons diagnosed with cancer during adolescence have reported negative and positive cancer-related consequences two years after diagnosis. The overall aim was to longitudinally describe negative and positive cancer-related consequences reported by the same persons three and four years after diagnosis. A secondary aim was to explore whether reports of using vs. not using certain coping strategies shortly after diagnosis are related to reporting or not reporting certain consequences four years after diagnosis. Thirty-two participants answered questions about coping strategies shortly after diagnosis and negative and positive consequences three and four years after diagnosis. Answers about consequences were analysed with content analysis, potential relations between coping strategies and consequences were analysed by Fisher's exact test. The great majority reported negative and positive consequences three and four years after diagnosis and the findings indicate stability over time with regard to perceived consequences during the extended phase of survival. Findings reveal a potential relation between seeking information shortly after diagnosis and reporting a more positive view of life four years after diagnosis and not using fighting spirit shortly after diagnosis and not reporting good self-esteem and good relations four years after diagnosis. It is concluded that concomitant negative and positive cancer-related consequences appear stable over time in the extended phase of survival and that dialectical forces of negative and positive as well as distress and growth often go hand-in-hand after a trauma such as cancer during adolescence

    A previously unidentified Chorioptes species infesting outer ear canals of moose (Alces alces): characterization of the mite and the pathology of infestation

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    <p>Abstract</p> <p>Background</p> <p>During the past decade, <it>Chorioptes </it>mites occupying the outer ear canals have been a common finding at routine necropsies of moose (<it>Alces alces</it>) in Sweden, but neither the taxonomy of the mites nor lesions from the infestation have been investigated. In this study, the mites are characterized by morphological and molecular techniques, and the histopathology of the skin of the outer ear canal is described.</p> <p>Methods</p> <p>External auditory meatuses from 53 necropsied moose were examined for the presence of <it>Chorioptes</it>, and samples from outer ear canals were taken for histopathological and microbiological examination. A proportion of the mites from each moose was identified to species. The DNA was extracted from mites from three moose, and their ITS-2 sequences were determined; these sequences were compared phylogenetically to sequences from other <it>Chorioptes </it>taxa.</p> <p>Results</p> <p><it>Chorioptes </it>mites were found in 43 (81%) of the 53 moose. The mites had morphological and genetic characteristics distinct from those of <it>C. texanus </it>and <it>C. bovis</it>, the two species generally accepted within the genus. Morphology also did not argue for a diagnosis as <it>C. crewei</it>, <it>C. mydaus </it>or <it>C. panda</it>. On histopathology, lesions were characterized by a hyperplastic perivascular to interstitial dermatitis with epidermal hyperkeratosis and crust formation. Dermal inflammatory infiltrates were composed of mixed T- and B-lymphocytes, plasma cells and macrophages, whereas eosinophils were notably uncommon. <it>Staphylococcus aureus </it>was grown from the infested epidermis of five of 14 examined moose.</p> <p>Conclusion</p> <p><it>Chorioptes </it>mite infestation was frequently detected in the outer ear canals of moose in Sweden. The mites were evidently pathogenic, being associated with inflammatory lesions of the external auditory meatus. Our studies indicate infestations with a previously undescribed <it>Chorioptes </it>species.</p

    Training the next generation of plastics pollution researchers: tools, skills and career perspectives in an interdisciplinary and transdisciplinary field

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    Plastics pollution research attracts scientists from diverse disciplines. Many Early Career Researchers (ECRs) are drawn to this field to investigate and subsequently mitigate the negative impacts of plastics. Solving the multi-faceted plastic problem will always require breakthroughs across all levels of science disciplinarity, which supports interdisciplinary discoveries and underpins transdisciplinary solutions. In this context, ECRs have the opportunity to work across scientific discipline boundaries and connect with different stakeholders, including industry, policymakers and the public. To fully realize their potential, ECRs need to develop strong communication and project management skills to be able to effectively interface with academic peers and non-academic stakeholders. At the end of their formal education, many ECRs will choose to leave academia and pursue a career in private industry, government, research institutes or non-governmental organizations (NGOs). Here we give perspectives on how ECRs can develop the skills to tackle the challenges and opportunities of this transdisciplinary research field and how these skills can be transferred to different working sectors. We also explore how advisors can support an ECRs’ growth through inclusive leadership and coaching. We further consider the roles each party may play in developing ECRs into mature scientists by helping them build a strong foundation, while also critically assessing problems in an interdisciplinary and transdisciplinary context. We hope these concepts can be useful in fostering the development of the next generation of plastics pollution researchers so they can address this global challenge more effectively

    Subaqueous basaltic magmatic explosions trigger phreatomagmatism: a case study from Askja, Iceland

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    Sequences of basaltic pillow lavas that transition upwards with systematic gradation from pillow fragment breccias to fluidal bomb-bearing breccia to bomb-bearing lapilli tuffs are common at Askja volcano, Iceland. Based on the detailed textural investigation of three of these sequences, we argue that they record temporally continuous transition from effusive to explosive products that were erupted from and deposited at or near a single subaqueous vent. The recognition of such sequences is important as they provide evidence for controls on the onset of explosive activity in subaqueous environments. Such investigations are complicated by the interplay of magmatic gas expansion, phreatomagmatic and mechanical granulation fragmentation mechanisms in the subaqueous eruptive environment. All of the sequences studied at Askja have textural, componentry and sedimentological characteristics suggestive of a close genetic and spatial relationship between the pillow lavas and all of the overlying glassy clastic deposits. The identification of magma fragmentation signatures in pyroclasts was accomplished through detailed textural studies of pyroclasts within the full range of grain sizes of a given deposit i.e. bomb/blocks, lapilli and fine ash. These textural characteristics were compared and evaluated as discriminators of fragmentation in pyroclastic deposits. The presence of angular vitric clasts within the breccia and lapilli tuff displaying fragile glassy projections indicates little or no postdepositional textural modification. A shift in vesicle and clast textures between the pillow lavas and the large concentration of fluidal bombs in the breccia indicate that the phreatomagmatic explosions were initially triggered by magmatic vesiculation. The initial magmatic gas expansion may have been triggered by depressurization caused by the drainage of the ice-confined lake surrounding Askja. The Fuel Coolant Interactions (FCI) of the more efficient phreatomagmatic explosion was enabled by the increase in the surface area to volume ratio of the fluidal bombs in the water, producing a premix of magma and water. The onset and increasing influence of phreatomagmatic fragmentation is preserved in the presence of very fine blocky ash particles and diminished presence of larger particles such as fluidal bombs. The textural, sedimentological and environmental characteristics of these deposits suggest that phreatomagmatic explosions can be triggered by initial magmatic gas expansion, but that it is likely one of many mechanisms for triggering such explosions

    Severe Airway Epithelial Injury, Aberrant Repair and Bronchiolitis Obliterans Develops after Diacetyl Instillation in Rats

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    Bronchiolitis obliterans (BO) is a fibrotic lung disease that occurs in a variety of clinical settings, including toxin exposures, autoimmunity and lung or bone marrow transplant. Despite its increasing clinical importance, little is known regarding the underlying disease mechanisms due to a lack of adequate small animal BO models. Recent epidemiological studies have implicated exposure to diacetyl (DA), a volatile component of artificial butter flavoring, as a cause of BO in otherwise healthy factory workers. Our overall hypothesis is that DA induces severe epithelial injury and aberrant repair that leads to the development of BO. Therefore, the objectives of this study were 1) to determine if DA, delivered by intratracheal instillation (ITI), would lead to the development of BO in rats and 2) to characterize epithelial regeneration and matrix repair after ITI of DA.Male Sprague-Dawley rats were treated with a single dose of DA (125 mg/kg) or sterile water (vehicle control) by ITI. Instilled DA resulted in airway specific injury, followed by rapid epithelial regeneration, and extensive intraluminal airway fibrosis characteristic of BO. Increased airway resistance and lung fluid neutrophilia occurred with the development of BO, similar to human disease. Despite rapid epithelial regeneration after DA treatment, expression of the normal phenotypic markers, Clara cell secretory protein and acetylated tubulin, were diminished. In contrast, expression of the matrix component Tenascin C was significantly increased, particularly evident within the BO lesions.We have established that ITI of DA results in BO, creating a novel chemical-induced animal model that replicates histological, biological and physiological features of the human disease. Furthermore, we demonstrate that dysregulated epithelial repair and excessive matrix Tenacin C deposition occur in BO, providing new insights into potential disease mechanisms and therapeutic targets

    Analysis of Transportation Networks Subject To Natural Hazards – insights from a Colombian case

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    ABSTRACT: This study provides an applied framework to derive the connectivity reliability and vulnerability of inter-urban transportation systems under network disruptions. The proposed model integrates statistical reliability analysis to find the reliability and vulnerability of transportation networks. Most of the modern research in this field has focused on urban transportation networks where the primary concerns are guaranteeing predefined standards of capacity and travel time. However, at a regional and national level, especially in developing countries, the connectivity of remote populations in the case of disaster is of utmost importance. The applicability of the framework is demonstrated with a case study in the state of Antioquia, Colombia, using historical records from the 2010-2011 rainy season, an aspect that stands out and gives additional support compared to previous studies that considers simulated data from assumed distributions. The results provide significant insights to practitioners and researchers for the design and management of transportation systems and route planning strategies under this type of disruptions

    The dynamics of experiential learning: Microprocesses and adaptation in a professional service INV

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    In international new ventures (INVs), experiential learning happens in quick succession and across a wide number of diverse contexts. Yet, we lack an empirical understanding of the microprocesses through which INVs learn and adapt in their foreign expansion. Understanding those microprocesses is important because timely adaptation can save the venture time and resources, thus promoting sustainable growth. In this study, we investigate the dynamics of experiential learning and adaptation in the internationalisation process of an INV in the professional service sector. Findings from our study illustrate that the firm applies deliberate experiential learning by developing, revising, and finalising criteria for important dimensions in the international growth process, and adapts its internationalisation practices accordingly. We further show that deliberate experiential learning is predicated on an actively and closely monitored learning process, involving critical evaluation, adjustment of criteria, and acceptance of affordable mistakes, as opposed to learning by defaul

    Subcellular distribution of human RDM1 protein isoforms and their nucleolar accumulation in response to heat shock and proteotoxic stress

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    The RDM1 gene encodes a RNA recognition motif (RRM)-containing protein involved in the cellular response to the anti-cancer drug cisplatin in vertebrates. We previously reported a cDNA encoding the full-length human RDM1 protein. Here, we describe the identification of 11 human cDNAs encoding RDM1 protein isoforms. This repertoire is generated by alternative pre-mRNA splicing and differential usage of two translational start sites, resulting in proteins with long or short N-terminus and a great diversity in the exonic composition of their C-terminus. By using tagged proteins and fluorescent microscopy, we examined the subcellular distribution of full-length RDM1 (renamed RDM1α), and other RDM1 isoforms. We show that RDM1α undergoes subcellular redistribution and nucleolar accumulation in response to proteotoxic stress and mild heat shock. In unstressed cells, the long N-terminal isoforms displayed distinct subcellular distribution patterns, ranging from a predominantly cytoplasmic to almost exclusive nuclear localization, suggesting functional differences among the RDM1 proteins. However, all isoforms underwent stress-induced nucleolar accumulation. We identified nuclear and nucleolar localization determinants as well as domains conferring cytoplasmic retention to the RDM1 proteins. Finally, RDM1 null chicken DT40 cells displayed an increased sensitivity to heat shock, compared to wild-type (wt) cells, suggesting a function for RDM1 in the heat-shock response
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