56 research outputs found

    Update of the Minimum Information About BIobank Data Sharing (MIABIS) Core Terminology to the 3<sup>rd</sup> Version

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    Introduction: The Minimum Information About BIobank Data Sharing (MIABIS) is a biobank-specific terminology enabling the sharing of biobank-related data for different purposes across a wide range of database implementations. After 4 years in use and with the first version of the individual-level MIABIS component Sample, Sample donor, and Event, it was necessary to revise the terminology, especially to include biobanks that work more in the data domain than with samples.Materials &amp; Methods: Nine use-cases representing different types of biobanks, studies, and networks participated in the development work. They represent types of data, specific sample types, or levels of organization that were not included earlier in MIABIS. To support our revision of the Biobank entity, we conducted a survey of European biobanks to chart the services they provide. An important stakeholder group for biobanks include researchers as the main users of biobanks. To be able to render MIABIS more researcher-friendly, we collected different sample/data requests to analyze the terminology adjustment needs in detail. During the update process, the Core terminology was iteratively reviewed by a large group of experts until a consensus was reached.Results: With this update, MIABIS was adjusted to encompass data-driven biobanks and to include data collections, while also describing the services and capabilities biobanks offer to their users, besides the retrospective samples. The terminology was also extended to accommodate sample and data collections of nonhuman origin. Additionally, a set of organizational attributes was compiled to describe networks.Discussion: The usability of MIABIS Core v3 was increased by extending it to cover more topics of the biobanking domain. Additionally, the focus was on a more general terminology and harmonization of attributes with the individual-level entities Sample, Sample donor, and Event to keep the overall terminology minimal. With this work, the internal semantics of the MIABIS terminology was improved

    Multi-parametric assessment of the anti-angiogenic effects of liposomal glucocorticoids

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    Inflammation plays a prominent role in tumor growth. Anti-inflammatory drugs have therefore been proposed as anti-cancer therapeutics. In this study, we determined the anti-angiogenic activity of a single dose of liposomal prednisolone phosphate (PLP-L), by monitoring tumor vascular function and viability over a period of one week. C57BL/6 mice were inoculated subcutaneously with B16F10 melanoma cells. Six animals were PLP-L-treated and six served as control. Tumor tissue and vascular function were probed using MRI before and at three timepoints after treatment. DCE-MRI was used to determine Ktrans, ve, time-to-peak, initial slope and the fraction of non-enhancing pixels, complemented with immunohistochemistry. The apparent diffusion coefficient (ADC), T2 and tumor size were assessed with MRI as well. PLP-L treatment resulted in smaller tumors and caused a significant drop in Ktrans 48 h post-treatment, which was maintained until one week after drug administration. However, this effect was not sufficient to significantly distinguish treated from non-treated animals. The therapy did not affect tumor tissue viability but did prevent the ADC decrease observed in the control group. No evidence for PLP-L-induced tumor vessel normalization was found on histology. Treatment with PLP-L altered tumor vascular function. This effect did not fully explain the tumor growth inhibition, suggesting a broader spectrum of PLP-L activities

    Effects of osteopontin inhibition on radiosensitivity of MDA-MB-231 breast cancer cells

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    <p>Abstract</p> <p>Background</p> <p>Osteopontin (OPN) is a secreted glycophosphoprotein that is overexpressed in various tumors, and high levels of OPN have been associated with poor prognosis of cancer patients. In patients with head and neck cancer, high OPN plasma levels have been associated with poor prognosis following radiotherapy. Since little is known about the relationship between OPN expression and radiosensitivity, we investigated the cellular and radiation induced effects of OPN siRNA in human MDA-MB-231 breast cancer cells.</p> <p>Methods</p> <p>MDA-MB-231 cells were transfected with OPN-specific siRNAs and irradiated after 24 h. To verify the OPN knockdown, we measured the OPN mRNA and protein levels using qRT-PCR and Western blot analysis. Furthermore, the functional effects of OPN siRNAs were studied by assays to assess clonogenic survival, migration and induction of apoptosis.</p> <p>Results</p> <p>Treatment of MDA-MB-231 cells with OPN siRNAs resulted in an 80% decrease in the OPN mRNA level and in a decrease in extracellular OPN protein level. Transfection reduced clonogenic survival to 42% (p = 0.008), decreased the migration rate to 60% (p = 0.15) and increased apoptosis from 0.3% to 1.7% (p = 0.04). Combination of OPN siRNA and irradiation at 2 Gy resulted in a further reduction of clonogenic survival to 27% (p < 0.001), decreased the migration rate to 40% (p = 0.03) and increased apoptosis to 4% (p < 0.005). Furthermore, OPN knockdown caused a weak radiosensitization with an enhancement factor of 1.5 at 6 Gy (p = 0.09) and a dose modifying factor (DMF<sub>10</sub>) of 1.1.</p> <p>Conclusion</p> <p>Our results suggest that an OPN knockdown improves radiobiological effects in MDA-MB-231 cells. Therefore, OPN seems to be an attractive target to improve the effectiveness of radiotherapy.</p

    Charge trapping in organic transistor memories: On the role of electrons and holes

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    In this work, we study charge trapping in organic transistor memories with a polymeric insulator as gate dielectric. We found that the mechanism of charge trapping is tunneling from the semiconductor channel into the gate dielectric. Depending on the semiconductor and its processing, charge trapping can result in large bi-directional threshold voltage shifts, in case the semiconductor is ambipolar, or in shifts in only one direction (unipolar semiconductor). These results indicate that optimal memory performance requires charge carriers of both polarities, because the most efficient method to lower the programming field is by overwriting a trapped charge by an injected charge of opposite polarity. (C) 2009 Elsevier B.V. All rights reserved.status: publishe

    An organic charge trapping memory transistor with bottom source and drain contacts

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    \u3cp\u3eWe present an organic charge trapping memory transistor with lithographically defined bottom source and drain contacts. This device can be written and erased at voltages as low as 15 V. More than 500 write and erase cycles and the retention of the trapped charge over more than three months are shown, demonstrating the possibilities of this device as a reprogramable nonvolatile organic memory element.\u3c/p\u3

    Charge trapping in organic transistor memories:On the role of electrons and holes

    No full text
    \u3cp\u3eIn this work, we study charge trapping in organic transistor memories with a polymeric insulator as gate dielectric. We found that the mechanism of charge trapping is tunneling from the semiconductor channel into the gate dielectric. Depending on the semiconductor and its processing, charge trapping can result in large bi-directional threshold voltage shifts, in case the semiconductor is ambipolar, or in shifts in only one direction (unipolar semiconductor). These results indicate that optimal memory performance requires charge carriers of both polarities, because the most efficient method to lower the programming field is by overwriting a trapped charge by an injected charge of opposite polarity.\u3c/p\u3
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