EBIC study of Au / n-type GaN Schottky contacts

The performance of Au / n-type GaN Schottky contacts is strongly dependent on the GaN surface processing prior to contacting. Current-voltage and EBIC line scans demonstrate that KOH treatment acts to degrade the Schottky contacts. EBIC imaging reveals the differing sub-grain boundary structures of MBE and MOCVD grown GaN / sapphire. The KOH treatment acts to uniformly change the properties of the GaN surface, rather than having a localised effect

Characterisation of dispersions within annealed HVOLF thermally sprayed AlSnCu coatings

High velocity oxy-liquid fuel (HVOLF) AlSnCu coatings are characterised following annealing for up to 5 hours at 300°C. A combination of statistical analysis of BSE images and TEM observations demonstrate the decrease in the number of sub-micron and nanoscale Sn particles with annealing, commensurate with a decrease in the coating microhardness. TEM evidence further suggests the coarsening of nanoscale Sn through a mechanism of a liquid phase migration within the Al matrix. EELS and EFTEM additionally allow the identification of the precipitation of theta'

Correlation of electrical and structural properties of Au contacts to KOH treated n-GaN

A correlated current-voltage (I-V), electron beam induced conductivity (EBIC) and X-ray photoelectron spectroscopy (XPS) study of Au contacts to KOH treated n-type GaN is presented. A strong degradation of I-V characteristics occurs following the KOH treatment, mirrored in a reduction in the magnitude of the EBIC current, even though the EBIC images look visibly unaltered. XPS demonstrates a modification in the surfaces states, e.g. resulting in a –0.3eV shift in the binding energy of Ga3d for MBE GaN following KOH processing

Direct detection of electron backscatter diffraction patterns.

We report the first use of direct detection for recording electron backscatter diffraction patterns. We demonstrate the following advantages of direct detection: the resolution in the patterns is such that higher order features are visible; patterns can be recorded at beam energies below those at which conventional detectors usefully operate; high precision in cross-correlation based pattern shift measurements needed for high resolution electron backscatter diffraction strain mapping can be obtained. We also show that the physics underlying direct detection is sufficiently well understood at low primary electron energies such that simulated patterns can be generated to verify our experimental data

TEM studies of multilayer ohmic contacts to n-type AlGaN/GaN

Ti and Pd barrier layers between the Al/Ti diffusion couple and the Au capping layer of multilayer ohmic contacts to n-type AlGaN/GaN field effect transistors were found to be ineffective in preventing the diffusion of Au to the AlGaN following high temperature rapid thermal annealing. The formation of a band of TiN grains at the contact/AlGaN interface is responsible for the activation of the contact. The presence of interfacial Au and threading dislocations are implicated in the formation of additional Ti-nitride inclusions into the AlGaN, although these do not appear to disrupt the Ti-nitride layer at the original contact/nitride interface, nor significantly influence the contact resistance

Un procedeu original de construcţie şi utilizare a lamboului nazogenian

Introduction. The classical naso-labial fl ap used for the reconstruction of tongue and oral floor presents multiple drawbacks. As an alternative to the classical one we present an original procedure of preparation of the naso-labial fl ap evaluated after seven years of use. Material and Method. The procedure we used was fi rst applied in the Oral and Maxillofacial Surgery Clinic in Cluj-Napoca seven years ago on patients suffering from tongue and/or oral floor malignancies in order to reconstruct these anatomical areas after the excision of the tumours in oncological safe limits. Most of its preparation procedure was made according to the classical method with some modifi cations in the preparation of its base. In order to enhance its covering area and functional availability and to eliminate some drawbacks, the route to the receptor area was changed. The submandibular course was used instead of the transbuccal one. Results. In all 21 patients who underwent surgery, a considerable enhancement of fl ap covering availability was obtained. It was able to cover defects ranging from the posterior limits of the tongue and oral fl oor to the tongue tip even beyond the midline. Unlike in the classical method there was no need to perform tooth extractions in dentulous patients. It is a one step procedure. Thus, the second step of the classical method was eliminated. Conclusions. The naso-labial fl ap with submandibular course offers covering and functional availability superior than the classical one with transbuccal route. It preserves and reconstructs the perimandibular anatomical sites. It also shortens the surgical treatment period of tongue and oral floor malignancies

Transforming growth factor β-mediated micromechanics modulates disease progression in primary myelofibrosis.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadPrimary myelofibrosis (PMF) is a Ph-negative myeloproliferative neoplasm (MPN), characterized by advanced bone marrow fibrosis and extramedullary haematopoiesis. The bone marrow fibrosis results from excessive proliferation of fibroblasts that are influenced by several cytokines in the microenvironment, of which transforming growth factor-β (TGF-β) is the most important. Micromechanics related to the niche has not yet been elucidated. In this study, we hypothesized that mechanical stress modulates TGF-β signalling leading to further activation and subsequent proliferation and invasion of bone marrow fibroblasts, thus showing the important role of micromechanics in the development and progression of PMF, both in the bone marrow and in extramedullary sites. Using three PMF-derived fibroblast cell lines and transforming growth factor-β receptor (TGFBR) 1 and 2 knock-down PMF-derived fibroblasts, we showed that mechanical stress does stimulate the collagen synthesis by the fibroblasts in patients with myelofibrosis, through the TGFBR1, which however seems to be activated through alternative pathways, other than TGFBR2. Keywords: TGF-β; fibroblast activation; invasion; micromechanics; myelofibrosis; proliferation.School of Doctoral Studies-Iuliu Hatieganu University Romanian Government Ion Chiricuta Oncology Institute Cluj Napoca international collaborative grant of the European Economic Space between Romania and Iceland 2020-2022 1

A prospective survey in European Society of Cardiology member countries of atrial fibrillation management: baseline results of EURO bservational Research Programme Atrial Fibrillation (EORP-AF) Pilot General Registry

Aims: Given the advances in atrial fibrillation (AF) management and the availability of new European Society of Cardiology (ESC) guidelines, there is a need for the systematic collection of contemporary data regarding the management and treatment of AF in ESC member countries. Methods and results: We conducted a registry of consecutive in- and outpatients with AF presenting to cardiologists in nine participating ESC countries. All patients with an ECG-documented diagnosis of AF confirmed in the year prior to enrolment were eligible. We enroled a total of 3119 patients from February 2012 to March 2013, with full data on clinical subtype available for 3049 patients (40.4% female; mean age 68.8 years). Common comorbidities were hypertension, coronary disease, and heart failure. Lone AF was present in only 3.9% (122 patients). Asymptomatic AF was common, particularly among those with permanent AF. Amiodarone was the most common antiarrhythmic agent used (~20%), while beta-blockers and digoxin were the most used rate control drugs. Oral anticoagulants (OACs) were used in 80% overall, most often vitamin K antagonists (71.6%), with novel OACs being used in 8.4%. Other antithrombotics (mostly antiplatelet therapy, especially aspirin) were still used in one-third of the patients, and no antithrombotic treatment in only 4.8%. Oral anticoagulants were used in 56.4% of CHA 2DS2-VASc = 0, with 26.3% having no antithrombotic therapy. A high HAS-BLED score was not used to exclude OAC use, but there was a trend towards more aspirin use in the presence of a high HAS-BLED score. Conclusion: The EURObservational Research Programme Atrial Fibrillation (EORP-AF) Pilot Registry has provided systematic collection of contemporary data regarding the management and treatment of AF by cardiologists in ESC member countries. Oral anticoagulant use has increased, but novel OAC use was still low. Compliance with the treatment guidelines for patients with the lowest and higher stroke risk scores remains suboptimal. © The Author 2013

EBIC study of Au / n-type GaN Schottky contacts

The performance of Au / n-type GaN Schottky contacts is strongly dependent on the GaN surface processing prior to contacting. Current-voltage and EBIC line scans demonstrate that KOH treatment acts to degrade the Schottky contacts. EBIC imaging reveals the differing sub-grain boundary structures of MBE and MOCVD grown GaN / sapphire. The KOH treatment acts to uniformly change the properties of the GaN surface, rather than having a localised effect

Correlation of electrical and structural properties of Au contacts to KOH treated n-GaN

A correlated current-voltage (I-V), electron beam induced conductivity (EBIC) and X-ray photoelectron spectroscopy (XPS) study of Au contacts to KOH treated n-type GaN is presented. A strong degradation of I-V characteristics occurs following the KOH treatment, mirrored in a reduction in the magnitude of the EBIC current, even though the EBIC images look visibly unaltered. XPS demonstrates a modification in the surfaces states, e.g. resulting in a –0.3eV shift in the binding energy of Ga3d for MBE GaN following KOH processing