Hemodynamic determinants of left atrial strain in patients with hypertrophic cardiomyopathy:A combined echocardiography and CMR study

BackgroundLeft atrial (LA) strain is associated with symptomatic status and atrial fibrillation in patients with hypertrophic cardiomyopathy (HCM). However, hemodynamic determinants of LA reservoir (LARS), conduit, and pump strains have not been examined and data are needed on the relation of LA strain with exercise tolerance in HCM.MethodsFifty HCM patients with echocardiographic and CMR imaging within 30 days were included. Left ventricular (LV) volumes, mass, EF, scar extent, extracellular volume fraction (ECV), and LA maximum volume were measured by CMR. Echo studies were analyzed for mitral inflow, pulmonary vein flow, mitral annulus tissue Doppler velocities, LV global longitudinal strain, and LA strain. Twenty six patients able and willing to exercise underwent cardiopulmonary stress testing for peak oxygen consumption (MVO2), and VE/VCO2 slope. Patients were followed for clinical events.FindingsLARS was significantly associated with indices of LA systolic function, LV GLS, and LV filling pressures (PConclusionsLV structure, systolic and diastolic function, and LA systolic function determine the 3 components of LA strain. LA strain is associated with exercise tolerance and clinical events in patients with HCM

Determination of intrinsic effective fields and microwave polarizations by high-resolution spectroscopy of single nitrogen-vacancy center spins

We present high-resolution optically detected magnetic resonance (ODMR) spectroscopy on single nitrogen-vacancy (NV) center spins in diamond at and around zero magnetic field. The experimentally observed transitions depend sensitively on the interplay between the microwave (MW) probing field and the local intrinsic effective field comprising strain and electric fields, which act on the NV spin. Based on a theoretical model of the magnetic dipole transitions and the MW driving field, we extract both the strength and the direction of the transverse component of the effective field. Our results reveal that for the diamond crystal under study, strain is the dominant contribution to the effective field. Our experiments further yield a method for MW polarization analysis in a tunable, linear basis, which we demonstrate on a single NV spin. Our results are of importance to low-field quantum sensing applications using NV spins and form a relevant addition to the ever-growing toolset of spin-based quantum sensing.Comment: 12 pages, 5 figures. Including appendi

Influence of anode thickness on the electrochemical performance of single chamber solid oxide fuel cells

The influence of the anode thickness (9–60 μm) on the behaviour of SC-SOFCs was investigated in different total flows of a methane-air mixture to the anode. In order to eliminate the effects of the cathode with varying flow, a double chamber setup with separated fuel and air streams to the anode and cathode was used. The open circuit voltage (OCV) decreased with increasing gas flow and at the same time the power density increased. Oscillations of the OCV at high gas flows were observed for cells with thin anodes. Cells with thick anodes showed the highest OCV and the highest maximum power density. These anodes have a higher catalytic activity for the partial oxidation of methane and create a lower oxygen partial pressure at the anode/electrolyte interface. They also provide more hydrogen than thin anodes and can give a higher power output

Initial experience with factor-Xa inhibition in percutaneous coronary intervention: the XaNADU-PCI Pilot

Background : Direct factor (F)Xa inhibition is an attractive method to limit thrombotic complications during percutaneous coronary intervention (PCI). Objectives : To investigate drug levels achieved, effect on coagulation markers, and preliminary efficacy and safety of several doses of DX-9065a, an intravenous, small molecule, direct, reversible FXa inhibitor during PCI. Patients and methods : Patients undergoing elective, native-vessel PCI ( n  = 175) were randomized 4 : 1 to open-label DX-9065a or heparin in one of four sequential stages. DX-9065a regimens in stages I–III were designed to achieve concentrations of > 100 ng mL −1 , > 75 ng mL −1 , and > 150 ng mL −1 . Stage IV used the stage III regimen but included patients recently given heparin. Results : At 15 min median (minimum) DX-9065a plasma levels were 192 (176), 122 (117), 334 (221), and 429 (231) ng mL −1 in stages I–IV, respectively. Median whole-blood international normalized ratios (INRs) were 2.6 (interquartile range 2.5, 2.7), 1.9 (1.8, 2.0), 3.2 (3.0, 4.1), and 3.8 (3.4, 4.6), and anti-FXa levels were 0.36 (0.32, 0.38), 0.33 (0.26, 0.39), 0.45 (0.41, 0.51), and 0.62 (0.52, 0.65) U mL −1 , respectively. Stage II enrollment was stopped ( n  = 7) after one serious thrombotic event. Ischemic and bleeding events were rare and, in this small population, showed no clear relation to DX-9065a dose. Conclusions : Elective PCI is feasible using a direct FXa inhibitor for anticoagulation. Predictable plasma drug levels can be rapidly obtained with double-bolus and infusion DX-9065a dosing. Monitoring of DX-9065a may be possible using whole-blood INR. Direct FXa inhibition is a novel and potentially promising approach to anticoagulation during PCI that deserves further study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74517/1/j.1538-7933.2004.00594.x.pd