Left ventricular diastolic function assessed using Doppler tissue imaging in patients with hypertrophic cardiomyopathy: relation to symptoms and exercise capacityBACKGROUND: Conventional Doppler indices of left ventricular diastolic function do not correlate with symptoms or exercise capacity in patients with hypertrophic cardiomyopathy, because of their dependence on loading conditions. Diastolic mitral annular velocity measured using Doppler tissue imaging has been reported to be a preload independent index of left ventricular diastolic function. OBJECTIVE: To determine the relation between diastolic annular velocities combined with conventional Doppler indices and symptoms or exercise capacity in hypertrophic cardiomyopathy. METHODS: 85 patients with hypertrophic cardiomyopathy and 60 normal controls were studied. Diastolic mitral annular velocities, transmitral left ventricular filling, and pulmonary venous velocities were measured. RESULTS: Early diastolic velocities at lateral and septal annulus were lower in patients with hypertrophic cardiomyopathy than in controls (lateral Ea: 10 (3) v 18 (4) cm/s, p < 0.0001; septal Ea: 7 (2) v 12 (3) cm/s, p < 0.0001). Unlike conventional Doppler indices alone, transmitral early left ventricular filling velocity (E) to lateral Ea ratio correlated inversely with peak oxygen consumption (r = -0.42, p < 0.0001). Patients in New York Heart Association (NYHA) class III had a higher transmitral E to lateral Ea ratio (12.0 (4.6)) than those in NYHA class II (7.6 (3.1), p < 0.005) or class I (6.6 (2.6), p < 0.0001). CONCLUSIONS: Early diastolic mitral annular velocities are reduced in patients with hypertrophic cardiomyopathy. Unlike conventional Doppler indices alone, the transmitral E to lateral Ea ratio correlates with NYHA functional class and exercise capacity.
Insect morphology in the age of phylogenomics: innovative techniques and its future role in systematicsFrank Friedrich, Yoko Matsumura, Hans Pohl et al.|Entomological Science|2013 Abstract A brief account of the history of insect morphology is given. Different techniques and analytical methods used in current projects on insect morphology and phylogeny and their optimized combined application are described. These include fixation, dissection, maceration, histology (microtome sectioning), scanning electron microscopy ( SEM ), transmission electron microscopy ( TEM ), serial block‐face scanning electron microscopy ( SBFSEM ), focused ion beam scanning electron microscopy ( FIB / SEM ), confocal laser scanning microscopy ( CLSM ), bleaching, micro‐computed tomography (μ CT ), computer‐based three‐dimensional reconstruction, focus stacking of digital images, geometric morphometrics and the storage of morphological metadata. The role of insect morphology in the “age of phylogenomics” is discussed.
Low voltage ride through capability enhancement of wind turbine generator system during network disturbanceS. M. Muyeen, Ryo Takahashi, T. Murata et al.|IET Renewable Power Generation|2008 The energy capacitor system (ECS), composed of power electronic devices and electric double layer capacitor to enhance the low voltage ride through (LVRT) capability of fixed speed wind turbine generator system (WTGS) during network disturbance, is discussed. Control scheme of ECS is based on a sinusoidal pulse width modulation voltage source converter and DC–DC buck/boost converter composed of insulated gate bipolar transistors. Two-mass drive train model of WTGS is adopted because the drive train system modelling has great influence on the characteristics of wind generator system during network fault. Extensive analysis of symmetrical fault is performed with different voltage dip magnitudes and different time durations. Permanent fault because of unsuccessful reclosing is also analysed, which is one of the salient features of this study. A real grid code defined in the power system is considered and LVRT characteristic of WTGS is analysed. Finally, it is concluded that ECS (20 MW) can significantly enhance the LVRT capability of grid connected WTGS (50 MW) during network disturbance, where simulations have been carried out by using PSCAD/EMTDC.
Transient stability simulation of power system including wind generator by PSCAD/EMTDCInduction machines are mostly used as generators in wind power stations. Since induction machines also have a stability problem, it is important to analyze the transient stability of the power system including wind power stations. This paper presents simulation analyses of transient stability of a power system including an induction generator performed by PSCAD/EMTDC.
Giant spermatozoa and a huge spermatheca: A case of coevolution of male and female reproductive organs in the ground louse Zorotypus impolitus (Insecta, Zoraptera)Romano Dallai, Marco Gottardo, David Mercati et al.|Arthropod Structure & Development|2013