122 research outputs found
Size-Dependence of the Wavefunction of Self-Assembled Quantum Dots
The radiative and non-radiative decay rates of InAs quantum dots are measured
by controlling the local density of optical states near an interface. From
time-resolved measurements we extract the oscillator strength and the quantum
efficiency and their dependence on emission energy. From our results and a
theoretical model we determine the striking dependence of the overlap of the
electron and hole wavefunctions on the quantum dot size. We conclude that the
optical quality is best for large quantum dots, which is important in order to
optimally tailor quantum dot emitters for, e.g., quantum electrodynamics
experiments.Comment: 5 pages, 3 figure
Long-Term Mortality Associated With Use of Carvedilol Versus Metoprolol in Heart Failure Patients With and Without Type 2 Diabetes:A Danish Nationwide Cohort Study
BACKGROUND: Carvedilol may have favorable glycemic properties compared with metoprolol, but it is unknown if carvedilol has mortality benefit over metoprolol in patients with type 2 diabetes (T2D) and heart failure with reduced ejection fraction (HFrEF). METHODS AND RESULTS: Using Danish nationwide databases between 2010 and 2018, we followed patients with newâonset HFrEF treated with either carvedilol or metoprolol for allâcause mortality until the end of 2018. Followâup started 120Â days after initial HFrEF diagnosis to allow initiation of guidelineâdirected medical therapy. There were 39Â 260 patients on carvedilol or metoprolol at baseline (mean age 70.8Â years, 35% women), of which 9355 (24%) had T2D. Carvedilol was used in 2989 (32%) patients with T2D and 10Â 411 (35%) of patients without T2D. Users of carvedilol had a lower prevalence of atrial fibrillation (20% versus 35%), but other characteristics appeared wellâbalanced between the groups. Totally 11Â 306 (29%) were deceased by the end of followâup. We observed no mortality differences between carvedilol and metoprolol, multivariableâadjusted hazard ratio (HR) 0.97 (0.90â1.05) in patients with T2D versus 1.00 (0.95â1.05) for those without T2D, P for difference =0.99. Rates of newâonset T2D were lower in users of carvedilol versus metoprolol; age, sex, and calendar year adjusted HR 0.83 (0.75â0.91), P<0.0001. CONCLUSIONS: In a contemporary clinical cohort of HFrEF patients with and without T2D, carvedilol was not associated with a reduction in longâterm mortality compared with metoprolol. However, carvedilol was associated with lowered risk of newâonset T2D supporting the assertion that carvedilol has a more favorable metabolic profile than metoprolol
Mass-Spectrometry Based Proteome Comparison of Extracellular Vesicle Isolation Methods:Comparison of ME-kit, Size-Exclusion Chromatography, and High-Speed Centrifugation
Extracellular vesicles (EVs) are small membrane-enclosed particles released by cells under various conditions specific to cells’ biological states. Hence, mass-spectrometry (MS) based proteome analysis of EVs in plasma has gained much attention as a method to discover novel protein biomarkers. MS analysis of EVs in plasma is challenging and EV isolation is usually necessary. Therefore, we compared differences in abundance, subtypes, and contamination for EVs isolated by high-speed centrifugation, size exclusion chromatography (SEC), and peptide-affinity precipitation (PAP/ME kit) for subsequent MS-based proteome analysis. Successful EV isolation was evaluated by nanoparticle-tracking analysis, immunoblotting, and transmission electron microscopy, while EV abundance, EV subtypes, and contamination was evaluated by label-free tandem MS. High-speed centrifugation and SEC isolates showed high EV abundance at the expense of contamination by non-EV proteins and lipoproteins, respectively. These two methods also resulted in EVs of a similar type, however, with smaller EVs in SEC isolates. PAP isolates had a relatively low EV abundance and high contamination. We consider high-speed centrifugation and SEC suitable as EV isolation for MS biomarker studies, where the choice between the two should depend on the scientific questions and whether the focus is on larger or smaller EVs or a combination of both
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