The quasi-free-standing nature of graphene on H-saturated SiC(0001)

We report on an investigation of quasi-free-standing graphene on 6H-SiC(0001) which was prepared by intercalation of hydrogen under the buffer layer. Using infrared absorption spectroscopy we prove that the SiC(0001) surface is saturated with hydrogen. Raman spectra demonstrate the conversion of the buffer layer into graphene which exhibits a slight tensile strain and short range defects. The layers are hole doped (p = 5.0-6.5 x 10^12 cm^(-2)) with a carrier mobility of 3,100 cm^2/Vs at room temperature. Compared to graphene on the buffer layer a strongly reduced temperature dependence of the mobility is observed for graphene on H-terminated SiC(0001)which justifies the term "quasi-free-standing".Comment: 3 pages, 3 figures, accepted for publication in Applied Physics Letter

Loneliness, Social Isolation and Their Difference: A Cross-Diagnostic Study in Persistent Depressive Disorder and Borderline Personality Disorder

Background: Interpersonal difficulties are a key feature of persistent depressive disorder (PDD) and borderline personality disorder (BPD). Caught in a vicious circle of dysfunctional interpersonal transaction, PDD and BPD patients are at great risk of experiencing prolonged loneliness. Loneliness, in turn, has been associated with the development of mental disorders and chronic illness trajectories. Besides, several factors may contribute to the experience of loneliness across the lifespan, such as social network characteristics, a history of childhood maltreatment (CM), and cognitive-affective biases such as rejection sensitivity (RS). This cross-diagnostic study approached the topic of perceived loneliness by comparing PDD and BPD patients with healthy controls (HC) in its interplay with symptom burden, social network characteristics, RS as well as CM. Method: Thirty-four PDD patients (DSM-5; 15 female, Mage = 38.2, SD = 12.3), 36 BPD patients (DSM-5; 19 female, Mage = 28.8, SD = 9.2), and 70 age- and gender-matched HC were assessed cross-sectionally using the following self-report measures: UCLA Loneliness Scale, Social Network Index (SNI; size, diversity, and embeddedness), Beck Depression Inventory (BDI-II), Borderline Symptom List (BSL-23), Childhood Trauma Questionnaire (CTQ), and Rejection Sensitivity Questionnaire (RSQ). Results: Both patient groups reported significantly higher levels of perceived loneliness, symptom severity, and smaller social network characteristics compared to HC. Loneliness was significantly correlated with severity of self-reported clinical symptoms in PDD and at trend level in BPD. Besides, loneliness tended to be related to social network characteristics for all groups except PDD patients. Both PDD and BPD patients showed higher RS as well as CTQ scores than HC. A history of emotional abuse and emotional neglect was associated with loneliness, and this association was mediated by RS as demonstrated by an exploratory mediation analysis. Discussion: Loneliness is highly prevalent in PDD and BPD patients and contributes to the overall symptom burden. Interestingly, loneliness showed an association with prior experiences of CM as well as current RS. We therefore propose a comprehensive model on how intra- und interpersonal aspects may interplay in the dynamics of loneliness in light of CM. Finally, this model may have further implications for psychotherapeutic interventions

Minimally invasive coronary artery bypass grafting versus percutaneous transluminal coronary angioplasty with stenting in isolated high-grade stenosis of the proximal left anterior descending coronary artery: Six months' angiographic and clinical follow-up of a prospective randomized study

AbstractObjective: We sought to compare minimally invasive coronary artery bypass grafting (surgical intervention) with percutaneous transluminal coronary angioplasty with primary stenting (stenting) in patients having an isolated high-grade stenosis (American College of Cardiology/American Heart Association classification type B2 or C) of the proximal left anterior descending coronary artery. At 6 months, both procedures were compared on the basis of quantitative angiography and clinical outcome. Methods: Both treatments were compared in a single-center, prospective, randomized study. The primary end point of this study was quantitative angiographic outcome at 6 months. The secondary end point was 6-month clinical outcome. Statistical analysis was performed in accordance with the intention-to-treat principle. Results: From March 1997 to September 1999, patients with angina pectoris caused by an isolated high-grade stenosis of the proximal left anterior descending coronary artery were randomly assigned to surgical intervention (n = 51) or stenting (n = 51). At 6 months, quantitative coronary angiography showed an anastomotic stenosis rate of 4% after surgical intervention and a restenosis rate of 29% after stenting (P <.001). Periprocedural events did not significantly differ between surgical intervention and stenting. After surgical intervention, 2 patients died; no patients died after stenting. After 6 months, no significant difference was found for major adverse cardiac or cerebral events and need for repeat target vessel revascularization. After 6 months, return of angina pectoris, physical work capacity, and use of antianginal drugs did not significantly differ between treatments. Conclusions: After 6 months, surgical intervention had a significantly better angiographic outcome than stenting in patients with an isolated high-grade stenosis of the proximal left anterior descending coronary artery. Clinical outcome did not significantly differ between treatments.J Thorac Cardiovasc Surg 2002;124:130-