412 research outputs found
High mobility dry-transferred CVD bilayer graphene
We report on the fabrication and characterization of high-quality chemical
vapor-deposited (CVD) bilayer graphene (BLG). In particular, we demonstrate
that CVD-grown BLG can mechanically be detached from the copper foil by an
hexagonal boron nitride (hBN) crystal after oxidation of the copper-to-BLG
interface. Confocal Raman spectroscopy reveals an AB-stacking order of the BLG
crystals and a high structural quality. From transport measurements on fully
encapsulated hBN/BLG/hBN Hall bar devices we extract charge carrier mobilities
up to 180,000 cm/(Vs) at 2 K and up to 40,000 cm/(Vs) at 300 K,
outperforming state-of-the-art CVD bilayer graphene devices. Moreover, we show
an on-off ration of more than 10,000 and a band gap opening with values of up
to 15 meV for a displacement field of 0.2 V/nm in such CVD grown BLG.Comment: 5 pages, 4 figure
The Effect of Dexamethasone, Adrenergic and Cholinergic Receptor Agonists on Phospholipid Metabolism in Human Osteoarthritic Synoviocytes
Phospholipids (PLs) possess the unique ability to contribute to synovial joint lubrication. The aim of our study was to determine for the first time the effect of dexamethasone and some adrenergic and cholinergic agonists on the biosynthesis and release of PLs from human fibroblast-like synoviocytes (FLS). Osteoarthritic human knee FLS were treated with dexamethasone, terbutaline, epinephrine, carbachol, and pilocarpine, or the glucocorticoid receptor antagonist RU 486. Simultaneously PL biosynthesis was determined through the incorporation of stable isotope-labeled precursors into PLs. Radioactive isotope-labeled precursors were used to radiolabel PLs for the subsequent quantification of their release into nutrient media. Lipids were extracted and quantified using electrospray ionization tandem mass spectrometry or liquid scintillation counting. Dexamethasone significantly decreased the biosynthesis of phosphatidylcholine, phosphatidylethanolamine (PE), PE-based plasmalogen, and sphingomyelin. The addition of RU 486 abolished these effects. A release of PLs from FLS into nutrient media was not recognized by any of the tested agents. None of the adrenergic or cholinergic receptor agonists modulated the PL biosynthesis. We demonstrate for the first time an inhibitory effect of dexamethasone on the PL biosynthesis of FLS from human knees. Moreover, our study indicates that the PL metabolism of synovial joints and lungs are differently regulated
Cerebrospinal fluid outflow along lumbar nerves and possible relevance for pain research: case report and review
CSF outflow through the cribriform plate near the olfactory
nerves and the outflow along brain and spinal nerves
are together known as peripheral CSF outflow pathway
(PCOP). It is still not clear whether the PCOP has pathogenetic
relevance. Our previous clinical observations have indicated
that CSF may interact with nerves along the PCOP
and in this article we present our finding of CSF outflow
demonstrated by myelography in a single patient. We also
discuss unexplained experimental pain pathomechanisms
against the background of the PCOP hypothesis. We observed
that CSF flowed along lumbar nerves in distal direction
at a speed of about 10 cm per hour on its way through
the tissues, mainly muscles. Total CSF outflow volume at
the lumbar site was remarkable. CSF outflow at lumbar
nerves was also documented by neuroradiology. It is plausible
that CSF signaling serves for interaction with nerves
along the PCOP, which could explain previously unknown
pathomechanisms in pain generation. Experimental findings
of tactile pain hypersensitivity within lumbosacral
pain pathways could be explained by releasing of molecules,
microparticles, or exosomes into the CSF by mast
cells, which then move with CSF outflow along the PCOP
and interact with nerves, initiating even retrograde synaptic
stripping
Raman spectroscopy as probe of nanometer-scale strain variations in graphene
Confocal Raman spectroscopy is a versatile, non-invasive investigation tool
and a major workhorse for graphene characterization. Here we show that the
experimentally observed Raman 2D line width is a measure of nanometer-scale
strain variations in graphene. By investigating the relation between the G and
2D line at high magnetic fields we find that the 2D line width contains
valuable information on nanometer-scale flatness and lattice deformations of
graphene, making it a good quantity for classifying the structural quality of
graphene even at zero magnetic field.Comment: 7 pages, 4 figure
Development and Realisation of a Real-Time High Precision Positioning SSR-RTK Service for the North Sea Exclusive Economic Zone
In a two-year research and development project, the prototype of a GNSS (Global Navigation Satellite System) based real-time service using a SSR-RTK (State Space Representation-Real Time Kinematic) approach was developed for the German exclusive economic zone in the North Sea. Because the survey area of the North Sea can only be represented with a heterogeneous distribution of GNSS Continuously Operating Reference Stations, the calculation algorithm and the modelling of the GNSS correction data are particularly important. Maritime measurements in the survey area have confirmed the basic functionality of the prototype through an almost 90% availability of the RTK status fix with initialisation times of less than two minutes. Sea and land measurements as well as a permanent monitoring station were used to demonstrate the quality targets.En un proyecto de dos años de investigación y desarrollo, se desarrolló el prototipo de un servicio en tiempo real basado en GNSS (Sistema Global de Navegación por Satélite) usando un enfoque SSR-RTK (Cinemática en Tiempo Real – Representación del Espacio Nacional) para la zona económica exclusiva alemana en el Mar del Norte. Como el área de levantamientos del Mar del Norte solo se puede representar mediante una distribución heterogénea de Estaciones de Referencia GNSS en Funcionamiento Constante, el algoritmo de cálculo y el modelado de los datos de corrección del GNSS son particularmente importantes. Las mediciones marítimas en el área de levantamientos han confirmado la funcionalidad básica del prototipo hasta casi el 90% de disponibilidad de la determinación de estado RTK con tiempos de inicialización de menos de dos minutos. Se usaron mediciones en tierra y mar además de una estación de control permanente para demostrar los objetivos de calidad.Dans le cadre d’un projet de recherche et développement de deux ans, le prototype d’un service en temps réel basé sur un GNSS (Global Navigation Satellite System) utilisant une approche SSR-RTK (State Space Representation-Real Time Kinema-tic) a été développé pour la zone économique exclusive allemande en mer du Nord. Étant donné que la zone d’étude de la mer du Nord ne peut être représentée qu’avec une distribution hétérogène des stations de référence GNSS en exploitation continue, l’algorithme de calcul et la modélisation des données de correction GNSS sont particulièrement importants. Les mesures à la mer dans la zone d’étude ont confirmé la fonctionnalité de base du prototype grâce à une disponibilité de près de 90% du correctif RTK avec des temps d’initialisation inférieurs à deux minutes. Des mesures en mer et à terre ainsi qu’une station de contrôle permanente ont été utili-sées pour démontrer les objectifs de qualité
Dental and Maxillofacial Cone Beam CT-High Number of Incidental Findings and Their Impact on Follow-Up and Therapy Management.
Cone beam computed tomography (CBCT) is increasingly used for dental and maxillofacial imaging. The occurrence of incidental findings has been reported, but clinical implications of these findings remain unclear. The study's aim was to identify the frequency and clinical impact of incidental findings in CBCT. A total of 374 consecutive CBCT examinations of a 3 year period were retrospectively evaluated for the presence, kind, and clinical relevance of incidental findings. In a subgroup of 54 patients, therapeutic consequences of CBCT incidental findings were queried from the referring physicians. A total of 974 incidental findings were detected, involving 78.6% of all CBCT, hence 2.6 incidental findings per CBCT. Of these, 38.6% were classified to require treatment, with an additional 25.2% requiring follow-up. Incidental findings included dental pathologies in 55.3%, pathologies of the paranasal sinuses and airways in 29.2%, osseous pathologies in 14.9% of all CBCT, and findings in the soft tissue or TMJ in few cases. Clinically relevant dental incidental findings were detected significantly more frequently in CBCT for implant planning compared to other indications (60.7% vs. 43.2%, p < 0.01), and in CBCT with an FOV ≥ 100 mm compared to an FOV < 100 mm (54.7% vs. 40.0%, p < 0.01). Similar results were obtained for paranasal incidental findings. In a subgroup analysis, 29 of 54 patients showed incidental findings which were previously unknown, and the findings changed therapeutical management in 19 patients (35%). The results of our study highlighted the importance of a meticulous analysis of the entire FOV of CBCT for incidental findings, which showed clinical relevance in more than one in three patients. Due to a high number of clinically relevant incidental findings especially in CBCT for implant planning, an FOV of 100 × 100 mm covering both the mandible and the maxilla was concluded to be recommendable for this indication
Deep metagenome and metatranscriptome analyses of microbial communities affiliated with an industrial biogas fermenter, a cow rumen, and elephant feces reveal major differences in carbohydrate hydrolysis strategies
Additional file 4. Compressed rar file containing the bins generated from the biogas fermenter metagenome, part 4 of 4
Assessment of the extent of unpublished studies in prognostic factor research: a systematic review of p53 immunohistochemistry in bladder cancer as an example
Objectives: When study groups fail to publish their results, a subsequent systematic review may come to incorrect conclusions when combining information only from published studies. p53 expression measured by immunohistochemistry is a potential prognostic factor in bladder cancer. Although numerous studies have been conducted, its role is still under debate. The assumption that unpublished studies too harbour evidence on this research topic leads to the question about the attributable effect when adding this information and comparing it with published data. Thus, the aim was to identify published and unpublished studies and to explore their differences potentially affecting the conclusion on its function as a prognostic biomarker.
Design: Systematic review of published and unpublished studies assessing p53 in bladder cancer in Germany between 1993 and 2007.
Results: The systematic search revealed 16 studies of which 11 (69%) have been published and 5 (31%) have not. Key reason for not publishing the results was a loss of interest of the investigators. There were no obviously larger differences between published and unpublished studies. However, a meaningful meta-analysis was not possible mainly due to the poor (ie, incomplete) reporting of study results.
Conclusions: Within this well-defined population of studies, we could provide empirical evidence for the failure of study groups to publish their results that was mainly caused by loss of interest. This fact may be coresponsible for the role of p53 as a prognostic factor still being unclear. We consider p53 and the restriction to studies in Germany as a specific example, but the critical issues are probably similar for other prognostic factors and other countries
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