300 research outputs found
Schottky barrier formation at amorphous-crystalline interfaces of GeSb phase change materials
The electrical properties of amorphous-crystalline interfaces in phase change materials, which are important for rewritable optical data storage and for random access memory devices, have been investigated by surface scanning potential microscopy. Analysis of GeSb systems indicates that the surface potential of the crystalline phase is similar to 30-60 mV higher than that of the amorphous phase. This potential asymmetry is explained qualitatively by the presence of a Schottky barrier at the amorphous-crystalline interface and supported also by quantitative Schottky model calculations. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3691179
Identification of occult metastases of medullary thyroid carcinoma by pentagastrin-stimulated intravenous calcitonin sampling followed by targeted surgery
BACKGROUND: High calcitonin (CT) serum levels suggest metastatic spread in medullary thyroid carcinoma (MTC) after thyroidectomy. In limited disease stages, however, morphological investigations including ultrasound, magnetic resonance imaging (MRI) and 18F-FDG positron emission tomography ([18F]FDG-PET) may often fail to identify exact tumour sites. OBJECTIVE: The aim of the present study was to establish an improved strategy to identify small cervical tumours by combining pentagastrin stimulation with bilateral cervical intravenous CT sampling followed by high-resolution ultrasound. DESIGN AND PATIENTS: Six MTC patients were examined, of whom five patients already had bilateral neck dissection. Five patients had sporadic MTC, and one patient suffered from MEN2a. RESULTS: Retrospective analysis of all patients revealed a highly sensitive positive correlation between an early calcitonin peak (20â40 s after pentagastrin injection) and site of cervical tumour affection. Postinterventional ultrasound examination of the affected regions of the neck revealed suspicious presence; in some cases small lymph nodes of less than 1 cm in size were then surgically excised. On histology, small tumours could be identified in four patients. Postsurgical examination revealed a clear decline of basal serum calcitonin levels in four patients (between â41% and â100%). In two patients CT normalized to baseline levels (< 10 pg/ml) and in another two patients CT rendered to near normal (14 and 17 pg/ml). CONCLUSION: Pentagastrin stimulation-based intravenous catheter sampling may be beneficial in the diagnostic work-up of MTC after thyroidectomy. Our data show that an early calcitonin peak (20â40 s after administration of pentagastrin) helps to identify tumour-affected regions
Institutions, policies, and arguments:context and strategy in EU policy framing
Studies of framing in the EU political system are still a rarity and they suffer from a lack of systematic empirical analysis. Addressing this gap, we ask if institutional and policy contexts intertwined with the strategic side of framing can explain the number and types of frames employed by different stakeholders. We use a computer-assisted manual content analysis and develop a fourfold typology of frames to study the frames that were prevalent in the debates on four EU policy proposals within financial market regulation and environmental policy at the EU level and in Germany, Sweden, the Netherlands and the United Kingdom. The main empirical finding is that both contexts and strategies exert a significant impact on the number and types of frames in EU policy debates. In conceptual terms, the article contributes to developing more fine-grained tools for studying frames and their underlying dimensions
Coming full circle: Differential empowerment in the EU accession process
The EU accession process brings a profound transformation not only to candidate countriesâ
institutions and policies, but also to the political opportunity structure in place, creating new
possibilities for previously marginalised actors. Studying the differential empowerment of
NGOs throughout the Croatian accession process, this paper makes two related claims: first,
differential empowerment depends crucially on domestic actorsâ awareness for and ability to
use new opportunities to their advantage. Second, an overreliance on EU leverage poses
important temporal and substantive limits on NGO empowerment and leads to a rapid decline
of their relevance in the post-accession phase. I argue that a more sustainable shift in the
domestic power balance would require both the EU and domestic civil society actors to place
more emphasis on fostering improved practices of civil society inclusion in domestic policymaking
settings throughout the accession process
Policy ideas through the prism of knowledge regimes and framing
Policymakers are often confronted with problems that involve ambiguity and uncertainty (Zahariadis, 2003). In order to make sense of such problems and to identify possible solutions, they are on the lookout for policy ideas
Genomic contributions to infant and toddler vocabulary scores: Implications for association with health-, cognition-, and behaviour-related outcomes
Mesenchymal tumor organoid models recapitulate rhabdomyosarcoma subtypes
Rhabdomyosarcomas (RMS) are mesenchyme-derived tumors and the most common childhood soft tissue sarcomas. Treatment is intense, with a nevertheless poor prognosis for high-risk patients. Discovery of new therapies would benefit from additional preclinical models. Here, we describe the generation of a collection of 19 pediatric RMS tumor organoid (tumoroid) models (success rate of 41%) comprising all major subtypes. For aggressive tumors, tumoroid models can often be established within 4-8âweeks, indicating the feasibility of personalized drug screening. Molecular, genetic, and histological characterization show that the models closely resemble the original tumors, with genetic stability over extended culture periods of up to 6âmonths. Importantly, drug screening reflects established sensitivities and the models can be modified by CRISPR/Cas9 with TP53 knockout in an embryonal RMS model resulting in replicative stress drug sensitivity. Tumors of mesenchymal origin can therefore be used to generate organoid models, relevant for a variety of preclinical and clinical research questions
Levonorgestrel-releasing intrauterine system versus endometrial ablation for heavy menstrual bleeding
Acknowledgments: We thank all the women who participated in this trial; the participating general practitioners, gynecologists, and hospitals; the research nurses; and the staff of the Dutch Consortium for Studies in Womenâs Health and Reproduction.Peer reviewedPublisher PD
Explaining telecoms and electricity internationalization in the European Union: a political economy perspective
One consequence of the liberalization of certain services in the European Union was that a number of formerly inward-looking incumbents in telecommunications and electricity rapidly transformed themselves into some of the worldâs leading Multinationals. However, the precise relationship between liberalization and incumbent internationalization is contested. This article tests three persuasive arguments derived from the political economy literature on this relationship. The first claims that those incumbents most exposed to domestic liberalization would internationalise most. The second asserts the opposite: incumbents operating where liberalization was restricted could exploit monopolistic rents to finance their aggressive internationalisation. The third argument claims that a diversity of paths will be adopted by countries and incumbents vis-Ă -vis liberalization and internationalization. Using correlation and cluster analysis of the sample of all major EU telecoms and electricity incumbent Multinationals evidence is found in favour of the third hypothesis. Internationalization as a response to liberalization took diverse forms in terms of timing and extent and this is best explained using a country, sector and firm logic
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