The prognostic value of left atrial and left ventricular strain in patients after ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention

Background: Global longitudinal strain (GLS) based on two-dimensional speckle-tracking echocardiography (2D-STE) might better reflect left ventricular (LV) contractile performance than conventional parameters. Recently, left atrial (LA) strain has been used as a more accurate alternative to assessing LA performance. The aim in this study was to assess the clinical prognostic value of left ventricular GLS (LV GLS) and peak atrial longitudinal strain (PALS) in patients after ST-segment elevation myocardial infarction (STEMI).Methods: The study enrolled 199 patients who underwent primary percutaneous coronary intervention (pPCI) for first STEMI. Conventional and 2D-STE were performed within 48 h after pPCI. LV GLS and PALS were related to LV remodeling at 6-month follow-up and to adverse events.Results: Diabetes mellitus, GLS and PALS independently predicted LV remodeling. With multivariable Cox proportional hazards, diabetes mellitus, GLS and PALS were predictive of adverse clinical outcomes. However, PALS did not add significant incremental value beyond LV GLS in the prediction of LV remodeling (increase in area under the receiver-operator characteristic curve [AUC]: 0.05, p = 0.24) and clinical events (even a decrease in AUC: 0.03, p = 0.69).Conclusions: Both GLS and PALS provide independent prognostic value for adverse LV remodeling and clinical outcomes after STEMI. However, the ability of the combination of PALS and GLS to predict LV remodeling and clinical outcomes may not be superior to that of a single indicator

Responses and receptive fields of amacrine cells and ganglion cells in the salamander retina

AbstractRetinal amacrine cells (ACs) and ganglion cells (GCs) have been shown to display large morphological diversity, and here we show that four types of ACs and three types of GCs exhibit physiologically-distinguishable properties. They are the sustained ON ACs; sustained OFF ACs; transient ON–OFF ACs; transient ON–OFF ACs with wide receptive fields; sustained ON-center/OFF-surround GCs; sustained OFF-center/ON-surround GCs and transient ON–OFF GCs. By comparing response waveforms, receptive fields and relative rod/cone inputs of ACs and GCs with the corresponding parameters of various types of the presynaptic bipolar cells (BCs), we analyze how different types of BCs mediate synaptic inputs to various ACs and GCs. Although more types of third-order retinal neurons may be identified by more refined classification criteria, our observations suggest that many morphologically-distinct ACs and GCs share very similar physiological responses

Sliding Mode Attitude Maneuver Control for Rigid Spacecraft without Unwinding

In this paper, attitude maneuver control without unwinding phenomenon is investigated for rigid spacecraft. First, a novel switching function is constructed by a hyperbolic sine function. It is shown that the spacecraft system possesses the unwinding-free performance when the system states are on the sliding surface. Based on the designed switching function, a sliding mode controller is developed to ensure the robustness of the attitude maneuver control system. Another essential feature of the presented attitude control law is that a dynamic parameter is introduced to guarantee the unwinding-free performance when the system states are outside the sliding surface. The simulation results demonstrate that the unwinding phenomenon is avoided during the attitude maneuver of a rigid spacecraft by adopting the constructed switching function and the proposed attitude control scheme.Comment: 8 Pages, 8 figures. arXiv admin note: text overlap with arXiv:2004.0700

Anti-Unwinding Sliding Mode Attitude Maneuver Control for Rigid Spacecraft

In this paper, anti-unwinding attitude maneuver control for rigid spacecraft is considered. First, in order to avoid the unwinding phenomenon when the system states are restricted to the switching surface, a novel switching function is constructed by hyperbolic sine functions such that the switching surface contains two equilibriums. Then, a sliding mode attitude maneuver controller is designed based on the constructed switching function to ensure the robustness of the closed-loop attitude maneuver control system to disturbance. Another important feature of the developed attitude control law is that a dynamic parameter is introduced to guarantee the anti-unwinding performance before the system states reach the switching surface. The simulation results demonstrate that the unwinding problem is settled during attitude maneuver for rigid spacecraft by adopting the newly constructed switching function and proposed attitude control scheme.Comment: 8 pages, 8 figure

The Allowed Parameter Space of a Long-lived Neutron Star as the Merger Remnant of GW170817

Due to the limited sensitivity of the current gravitational wave (GW) detectors, the central remnant of the binary neutron star (NS) merger associated with GW170817 remains an open question. In view of the relatively large total mass, it is generally proposed that the merger of GW170817 would lead to a short-lived hypermassive NS or directly produce a black hole (BH). There is no clear evidence to support or rule out a long-lived NS as the merger remnant. Here, we utilize the GW and electromagnetic (EM) signals to comprehensively investigate the parameter space that allows a long-lived NS to survive as the merger remnant of GW170817. We find that for some stiff equations of state, the merger of GW170817 could, in principle, lead to a massive NS, which has a millisecond spin period. The post-merger GW signal could hardly constrain the ellipticity of the NS. If the ellipticity reaches 10−3, in order to be compatible with the multi-band EM observations, the dipole magnetic field of the NS (B p ) is constrained to the magnetar level of ~1014 G. If the ellipticity is smaller than 10−4, B p is constrained to the level of ~109–1011 G. These conclusions weakly depend on the adoption of the NS equation of state