181 research outputs found

    High strain rate superplasticity at intermediate temperatures of the Al 7075 alloy severely processed by equal channel angular pressing

    Get PDF
    The mechanical properties of an overaged Al 7075-O alloy processed by ECAP were examined by tensile tests at intermediate-high temperatures ranging from 250 to 400ºC and strain rates from 10−5 to 10−1 s−1. The influence of the number of ECAP passes on the ductility enhancement was evaluated. Elongation to failure, eF, significantly increased with increasing the number of ECAP passes up to 8 at 130ºC. The alloy processed under these conditions exhibited a maximum value of 322% at 300ºC and an initial strain rate of 10−3 s−1. High strain rate superplasticity was obtained at this temperature, eF=210%, at strain rate as high as 10−2 s−1. The large elongations together with lower stresses and lower stress exponents than those for the start material confirm that grain boundary sliding (GBS) is the operative deformation mechanism. A loss of superplastic behaviour at above temperatures of 350ºC is related to abnormal grain growth and a change of deformation mechanism.Financial support from MICINN (Project MAT2009-14452) is gratefully acknowledged.Peer reviewe

    A Simple Approach of Presampled Modulation Transfer Function Measurement Tested on the Phoenix Nanotom Scanner

    Get PDF
    In this paper presampled modulation transfer function of the 2D images obtained on the Phoenix Nanotom scanner was investigated with different measurement set-ups. Three parameters were chosen to investigate their influence on modulation transfer function: source-detector distance, tube current and binning mode. A simple method for modulation transfer function determination of digital imaging detectors from edge images was applied. The following results were achieved and briefly discussed: modulation transfer function improves with increase of the source-detector distance, slightly improves with increase of the current and remains constant for different binning modes. All measurements were carried out in University of Applied Sciences Upper Austria at Wels campus

    Teratogenicity testing of BI 58 EC (38% dimethoate) in chicken embryos with special respect to degradation of the active ingredient

    Get PDF
    The insecticide formulation BI 58 EC was tested for teratogenicity in chicken embryos, with particular reference to degradation of the active ingredient (dimethoate) after the treatment of embryonated eggs. The pesticide was diluted in water to a concentration level of 0.8%, and the emulsion was injected into the air space in a volume of 0.1 ml/egg, or hen’s eggs were treated by the immersion technique. Residues of dimethoate were measured in the samples on days 13, 15 and 19 of the incubation of chicken embryos, and morphological examinations were performed simultaneously. Analytical chemistry data indicated a slower degradation of dimethoate in embryos after the immersion of eggs, and cyllosis was remarkable in this group among the sporadic developmental anomalies. The liver tissues ofboth treated groups exhibited severe fatty infiltration

    Pitfalls in mutational testing and reporting of common KIT and PDGFRA mutations in gastrointestinal stromal tumors

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Mutation analysis of <it>KIT </it>and <it>PDGFRA </it>genes in gastrointestinal stromal tumors is gaining increasing importance for prognosis of GISTs and for prediction of treatment response. Several groups have identified specific mutational subtypes in <it>KIT </it>exon 11 associated with an increased risk of metastatic disease whereas GISTs with <it>PDGFRA </it>mutations often behave less aggressive. Furthermore, in advanced GIST disease with proven <it>KIT </it>exon 9 mutation the doubled daily dose of 800 mg imatinib increases the progression free survival and is now recommended both in the European and the American Guidelines. In Germany, there are still no general rules how to perform mutational analysis.</p> <p>Methods</p> <p>When comparing results from six different molecular laboratories we recognized the need of standardisation. Six German university laboratories with experience in mutation analysis in GISTs joined together to develop recommendations for the mutation analysis of the most common and clinically relevant hot spots, i. e. <it>KIT </it>exons 9 and 11 and <it>PDGFRA </it>exon 18. We performed a three-phased interlaboratory trial to identify pitfalls in performing molecular analysis in GISTs.</p> <p>Results</p> <p>We developed a design for a continuous external laboratory trial. In 2009 this external trial was conducted by 19 laboratories via the initiative for quality assurance in pathology (QuiP) of the German Society of Pathology and the Professional Association of German Pathologists.</p> <p>Conclusions</p> <p>By performing a three-phased internal interlaboratory trial and conducting an external trial in Germany we were able to identify potential pitfalls when performing KIT and PDGFRA mutational analysis in gastrointestinal stromal tumors. We developed standard operation procedures which are provided with the manuscript to allow other laboratories to prevent these pitfalls.</p

    High-resolution DNA copy number and gene expression analyses distinguish chromophobe renal cell carcinomas and renal oncocytomas

    Get PDF
    Contains fulltext : 80487.pdf (publisher's version ) (Open Access)BACKGROUND: The diagnosis of benign renal oncocytomas (RO) and chromophobe renal cell carcinomas (RCC) based on their morphology remains uncertain in several cases. METHODS: We have applied Affymetrix GeneChip Mapping 250 K NspI high-density oligoarrays to identify small genomic alterations, which may occur beyond the specific losses of entire chromosomes, and also Affymetrix GeneChip HG-U133 Plus2.0 oligoarrays for gene expression profiling. RESULTS: By analysing of DNA extracted from 30 chRCCs and 42 ROs, we have confirmed the high specificity of monosomies of chromosomes 1, 2, 6, 10, 13, 17 and 21 in 70-93% of the chRCCs, while ROs displayed loss of chromosome 1 and 14 in 24% and 5% of the cases, respectively. We demonstrated that chromosomal gene expression biases might correlate with chromosomal abnormalities found in chromophobe RCCs and ROs. The vast majority genes downregulated in chromophobe RCC were mapped to chromosomes 2, 6, 10, 13 and 17. However, most of the genes overexpressed in chromophobe RCCs were located to chromosomes without any copy number changes indicating a transcriptional regulation as a main event. CONCLUSION: The SNP-array analysis failed to detect recurrent small deletions, which may mark loci of genes involved in the tumor development. However, we have identified loss of chromosome 2, 10, 13, 17 and 21 as discriminating alteration between chromophobe RCCs and ROs. Therefore, detection of these chromosomal changes can be used for the accurate diagnosis in routine histology

    Angiogenesis and lymphangiogenesis are downregulated in primary breast cancer

    Get PDF
    Angiogenesis and lymphangiogenesis are considered to play key roles in tumour growth, progression and metastasis. However, targeting tumour angiogenesis in clinical trials showed only modest efficacy. We therefore scrutinised the concept of tumour angiogenesis and lymphangiogenesis by analysing the expression of crucial markers involved in these processes in primary breast cancer. Methods: We analysed the expression of angiogenic, lymphangiogenic or antiangiogenic factors, their respective receptors and specific markers for endothelial and lymphendothelial cells by quantitative real-time RT-PCR in primary breast cancer and compared the expression profiles to non-cancerous, tumour-adjacent tissues and breast tissues from healthy women. Results: We found decreased mRNA amounts of major angiogenic and lymphangiogenic factors in tumour compared to healthy tissues, whereas antiangiogenic factors were upregulated. Concomitantly, angiogenic and lymphangiogenic receptors were downregulated in breast tumours. This antiangiogenic, antilymphangiogenic microenvironment was even more pronounced in aggressive tumours and accompanied by reduced amounts of endothelial and lymphatic endothelial cell markers. Conclusion: Primary breast tumours are not a site of highly active angiogenesis and lymphangiogenesis. Selection for tumour cells that survive with minimal vascular supply may account for this observation in clinical apparent tumours

    Evolution and environment of the eastern linear pottery culture: A case study in the site of Polgár-Piócási-Dűlő

    Get PDF
    A salvage excavation preceding a major investment project was conducted in 2006–2007, during which associated settlement features of a Middle Neolithic, Eastern Linear Pottery Culture (Alföld Linearbandkeramik – ALBK) were uncovered in an area called Piócási-dűlő on the eastern outskirts of Polgár. The features of the ALBK settlement date from two periods. The cluster of multi-functional pits yielding a rich assortment of finds, the handful of post-holes and an unusual ritual well found in the southern part of the investigated area formed one unit from the earliest phase of the Middle Neolithic (ALBK I). The settlement’s other occupation can be assigned to the late phase of the Middle Neolithic (ALBK IV). Five houseplans representing the remains of timber-framed buildings outlined a distinct area with three multi-functional pits. Associated with the above features were 8 burials. The preliminary archaeobotanical results from Polgár–Piócási-dűlő are based on the plant material found within the sediments of 11 archaeological structures, which mainly represent pits and a welI. It can be stated that the natural environment offered habitats in which oak trees dominated in the local vegetation, forming floodplain forests and wooded steppes. They also provided food in the form of fruits and formed an optimal habitat for domestic animals. Arable fields were probably also established in the vicinity of the settlements, suggested by findings of macroscopic plant remains that represented cultivated species. In both settlement phases lithic production activities are manifested both by the local on-site lithic production and – most importantly – by the presence of imported, mainly mesolocal, raw materials that point to contacts with deposit areas, or off-site preliminary working of obsidian and limnoquartzites. The kit of harvesting tools and a large number of grinding stones – especially in the younger phase – for the preparation of plant food suggest a major role of plant cultivation
    corecore