Deep and shallow electronic states associated to doping, contamination and intrinsic defects in ε-Ga2O3 epilayers

Deep and shallow electronic states in undoped and Si-doped ε-Ga2O3 epilayers grown by MOVPE on c-oriented Al2O3 were investigated by cathodoluminescence, optical absorption, photocurrent spectroscopy, transport measurements, and electron-paramagnetic-resonance. Nominally undoped films were highly resistive, with a room temperature resistivity varying in the range 107- 1013 Ωcm depending on the carrier gas used during growth. Films grown with He carrier were generally more resistive than those grown with H2 carrier and exhibited a Fermi level located at about 0.8 eV below the conduction band edge, which tends to shift deeper with temperature. This can tentatively be attributed to the combined action of deep donors (probably carbon impurities and oxygen vacancies) and deep acceptors (Ga vacancies and related complexes), which compensate residual shallow donors. There are strong experimental hints that nitrogen also behaves as deep acceptor. Room temperature resistivity as low as 0.42 Ωcm and electron concentrations around 1018 cm−3 were obtained by silicon doping. Si was confirmed to act as shallow donor with sufficiently high solubility. A variable range hopping conduction was observed in a wide temperature interval in the n-type layers, and compensation by native acceptors also plays a major role on conduction mechanisms. Previous evaluations of curvature and anisotropy of the conduction band are confirmed, which allows for the estimation of the electron effective mass. The present experimental data are discussed considering the theoretical predictions for point defect formation in the ε-polymorph as well as literature data on extrinsic and intrinsic defects in β-Ga2O3

Crystal structures of self-assembled nanotubes from flexible macrocycles by weak interactions

8 páginas, 7 figuras, 2 tablas, 2 esquemas.Herein we report the crystal structures of tubular self-assemblies of flexible macrooligolides. The assembly is driven by the propensity of the macrocycles to create nearly flat structures displaying a void space within them and the cooperativity of weak directional interactions such as dipole–dipole interactions and CH***Ohydrogen bonds and non-directional interactions such as van der Waals contacts. The significance of the stereochemistry and the size of the cavity in the formation of the nanotubes are also studied.This research was supported by the Spanish MICINN-FEDER (CTQ2008-03334/BQU, CTQ2008-06806-C02-01/BQU and CTQ2008-06754-C04-01/PPQ), the MSC (RTICC RD06/0020/ 1046) and the Canary Islands FUNCIS (PI 01/06).Peer reviewe

Predictors of short- and long-term outcomes of patients undergoing transcatheter mitral valve edge-to-edge repair

OBJECTIVES Transcatheter mitral valve repair (TMVR) by edge-to-edge therapy is an established treatment for severe mitral valve regurgitation (MR). BACKGROUND Symptomatic and prognostic benefit in functional MR has been shown recently; nevertheless, data on long-term outcomes are sparse. METHODS AND RESULTS We analyzed survival of patients treated with isolated edge-to-edge repair from June 2010 to March 2018 (primarily combined edge-to-edge repair with other mitral valve interventions was excluded) in a retrospective monocentric study. Overall, 627 consecutive patients (47.0% females, 78.6 years in mean) were included. Leading etiology was functional MR (57.4%). Follow-up regarding survival was available in 97.0%. While 97.6% were discharged alive, 75.7% were alive after a 1-year, 54.5% after 3-year, 37.6% after 5-year and 21.7% after 7-year follow-up. Higher logistic Euroscores and comorbidities such as COPD and renal insufficiency were associated with higher in-hospital and 1-year mortality. Importantly, in-hospital survival increased over the years. CONCLUSIONS With the present study we established high survival rates at discharge and after 1 year of patients treated with TMVR. This goes along with high implantation numbers, increased interventional experience and a better in-hospital survival over the years. Long-term mortality in turn was substantially influenced by comorbidities

Concomitant tricuspid regurgitation severity and its secondary reduction determine long-term prognosis after transcatheter mitral valve edge-to-edge repair

BACKGROUND Concomitant tricuspid regurgitation (TR) is a common finding in mitral regurgitation (MR). Transcatheter repair (TMVR) is a favorable treatment option in patients at elevated surgical risk. To date, evidence on long-term prognosis and the prognostic impact of TR after TMVR is limited. METHODS Long-term survival data of patients undergoing isolated edge-to-edge repair from June 2010 to March 2018 (combinations with other forms of TMVR or tricuspid valve therapy excluded) were analyzed in a retrospective monocentric study. TR severity was categorized and the impact of TR on survival was analysed. RESULTS Overall, 606 patients [46.5% female, 56.4% functional MR (FMR)] were enrolled in this study. TR at baseline was categorized severe/medium/mild/no or trace in 23.2/34.3/36.3/6.3% of the cases. At 30-day follow-up, improvement of at least one TR-grade was documented in 34.9%. Severe TR at baseline was identified as predictor of 1-year survival [65.2% vs. 77.0%, p = 0.030; HR for death 1.68 (95% CI 1.12–2.54), p = 0.013] and in FMR-patients also regarding long-term prognosis [adjusted HR for long-term mortality 1.57 (95% CI 1.00–2.45), p = 0.049]. Missing post-interventional reduction of TR severity was predictive for poor prognosis, especially in the FMR-subgroup [1-year survival: 92.9% vs. 78.3%, p = 0.025; HR for death at 1-year follow-up 3.31 (95% CI 1.15–9.58), p = 0.027]. While BNP levels decreased in both subgroups, TR reduction was associated with improved symptomatic benefit (NYHA-class-reduction 78.6 vs. 65.9%, p = 0.021). CONCLUSION In this large study, both, severe TR at baseline as well as missing secondary reduction were predictive for impaired long-term prognosis, especially in patients with FMR etiology. TR reduction was associated with increased symptomatic benefit

K⊂{[FeII^{II}(Tp)(CN)3_{3}]4_{4}[CoIII^{III}(pz^{pz}Tp)]3_{3}[CoII^{II}(pz^{pz}Tp)]}: a neutral soluble model complex of photomagnetic Prussian blue analogues

Straightforward access to a new cyanide-bridged {Fe$_{4}$Co$_{4}$} “molecular box” containing a potassium ion, namely K⊂{[Fe$^{II}$(Tp)(CN)$_{3}$]$_{4}$[Co$^{III}$($^{pz}$Tp)]$_{3}$[Co$^{II}$($^{pz}$Tp)]} (1) (with Tp and $^{pz}$Tp = tris- and tetrakis(pyrazolyl)borate, respectively), is provided, alongside its full characterisation. A detailed analysis of the molecular structure (X-ray diffraction, mass spectrometry, NMR spectroscopy) and electronic properties (EPR spectroscopy, SQUID magnetometry, UV/Vis spectroscopy, cyclic voltammetry) reveals that 1 shows slow magnetic relaxation and a remarkable photomagnetic effect at low temperature which is reminiscent of some FeCo Prussian Blue Analogues (PBAs), and is ascribed to a photo-induced electron transfer. However, in contrast with these inorganic polymers, the overall neutral compound 1 is soluble and remarkably stable in organic solvents such as CH2Cl2. Moreover, 1 shows interesting redox versatility, with electrochemical experiments revealing the possible access to six stable redox states

3D echocardiographic reference ranges for normal left ventricular volumes and strain: Results fromthe EACVI NORRE study

Aim To obtain the normal ranges for 3D echocardiography (3DE) measurement of left ventricular (LV) volumes, function, and strain from a large group of healthy volunteers. Methods and results A total of 440 (mean age: 45613 years) out of the 734 healthy subjects enrolled at 22 collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study had good-quality 3DE data sets that have been analysed with a vendor-independent software package allowing homogeneous measurements regardless of the echocardiographic machine used to acquire the data sets. Upper limits of LV end-diastolic and end-systolic volumes were larger in men (97 and 42 mL/m2) than in women (82 and 35 mL/m2; P<0.0001). Conversely, lower limits of LV ejection fraction were higher in women than in men (51% vs. 50%; P<0.01). Similarly, all strain components were higher in women than in men. Lower range was -18.6% in men and -19.5% in women for 3D longitudinal strain, -27.0% and -27.6% for 3D circumferential strain, -33.2% and -34.4% for 3D tangential strain and 38.8% and 40.7% for 3D radial strain, respectively. LV volumes decreased with age in both genders (P<0.0001), whereas LV ejection fraction increased with age only in men. Among 3DE LV strain components, the only one, which did not change with age was longitudinal strain. Conclusion The NORRE study provides applicable 3D echocardiographic reference ranges for LV function assessment. Our data highlight the importance of age- and gender-specific reference values for both LV volumes and strain. All rights reserved