P5350Atrial fibrillation prediction using P wave signal-averaged ECG in patients with embolic stroke of undetermined source

Background

Approximately 10–25% of ischemic strokes are of unknown origin. Determining their potential association with subclinical atrial fibrillation (SCAF) is important for proper secondary prevention. We investigated whether SCAF can be predicted by assessing the atrial substrate with signal-averaged electrocardiography (SAECG).

Methods

Between April 2015 and February 2018, we recruited 125 consecutive patients with embolic stroke of undetermined source (ESUS) and 125 patients with paroxysmal atrial fibrillation (AF) patients as control. All participants underwent P wave SAECG at baseline and ESUS patients were followed up with ECG and Holter ECG, at baseline, 3, 6, and 12 months after discharge, and every 12 months thereafter.

Results

In the ESUS group (69 males, 68.4±12.1 years), 32 (25.6%) patients were diagnosed with SCAF during follow-up. There were no significant differences between both groups in terms of P wave duration [PWD] (ESUS vs. AF, P=0.321). PWD demonstrated a significant predictive efficacy for SCAF detection during follow-up (C-index of standard PWD=0.657, 95% confidence interval (CI) 0.552–0.761, P=0.008).

Stroke recurrence occurred in 22 patients (17.6%) and was significantly associated with PWD but not SCAF (odds ratio 2.756, 95% CI 1.061–7.161, P=0.037).

Conclusion

PWD, an ECG biomarker associated with atrial substrate directly contributes to AF and ESUS, is useful for predicting SCAF. The potential for using this simple ECG biomarker for screening for SCAF amongst ESUS patients merits further exploration.

P3762The impact of type and burden of atrial fibrillation on stroke occurrence in patients with atrial fibrillation: from a prospective cohort of atrial fibrillation patients (CODE-AF Registry)

Background and purpose

Although several studies reported that stroke risk in patients with paroxysmal atrial fibrillation (AF) is similar to those with persistent or permanent AF, there is still controversy on the relationship of AF type and stroke occurrence. We investigated the effect of AF type on AF burden and stroke risk in patients with non-valvular AF.

Methods

Within the CODE-AF prospective, outpatient registry (COmparison study of Drugs for symptom control and complication prEvention of Atrial Fibrillation), we identified 8,883 patients ≥18 years of age with non-valvular AF and eligible follow-up visits. We compared AF burden and stroke risk among patients with 3 types of AF: paroxysmal (n=5,808) or persistent (n=2,806) or permanent (n=269).

Results

The median age of the overall population was 68.0 (interquartile range, 60.0–75.0); 36.0% were female. Patients with persistent and permanent AF were older and had higher CHA2DS2-VASc scores and anticoagulation rate than those with paroxysmal AF. Compared with permanent AF (5.2±16.4%), the arrhythmic burden of AF on 24hrs Holter monitoring was significantly lower in paroxysmal AF (2.1±7.2%, p<0.001) and persistent AF (2.0±7.5%, p<0.001). During median follow-up period of 1.38 years (interquartile range: 0.96–1.67), total 82 (0.92%) patients experienced ischemic stroke with incidence rates of 0.51, 1.04 and 1.69 events per 100 person-years for paroxysmal, persistent and permanent AF, respectively. Compared with paroxysmal AF, the risk of ischemic stroke was increased in persistent AF with clinical variable adjusted hazard ratio (aHR) of 1.94 (95% confidence intervals [CI], 1.23–3.07; P=0.005) and permanent AF with aHR of 2.64 (95% CI, 1.09–6.41; P=0.03).

AF type and HR of stroke occurrence Paroxysmal (n=5,808) Persistent (n=2,806) Permanent (n=269) Stoke events 39 37 6 Person years (PYs) 7673 3544 356 /100 PYs 0.51 1.04 1.69 HR (95% CI), p-value HR (95% CI), p-value HR (95% CI), p-value Unadjusted HR 1 (Reference) 2.05 (1.27–3.31), 0.003 3.32 (1.15–7.90), 0.02 Clinical variables adjusted HR 1 (Reference) 1.94 (1.23–3.07), 0.005 2.64 (1.09–6.41), 0.03 PYs: Person years; HR: Hazard ratio.

Conclusion

Persistent and permanent AF was associated with the increased risk of stroke than paroxysmal AF, after adjustment of clinical variables including age, sex, comorbidities and anticoagulation rate. These results suggest that AF type and burden might be related with the risk of ischemic stroke and should be considered in the stroke prevention of AF.

First Observation of an Attractive Interaction between a Proton and a Cascade Baryon

This Letter presents the first experimental observation of the attractive strong interaction between a proton and a multistrange baryon (hyperon) Ξ^{-}. The result is extracted from two-particle correlations of combined p-Ξ^{-}⊕p[over ¯]-Ξ[over ¯]^{+} pairs measured in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV at the LHC with ALICE. The measured correlation function is compared with the prediction obtained assuming only an attractive Coulomb interaction and a standard deviation in the range [3.6, 5.3] is found. Since the measured p-Ξ^{-}⊕p[over ¯]-Ξ[over ¯]^{+} correlation is significantly enhanced with respect to the Coulomb prediction, the presence of an additional, strong, attractive interaction is evident. The data are compatible with recent lattice calculations by the HAL-QCD Collaboration, with a standard deviation in the range [1.8, 3.7]. The lattice potential predicts a shallow repulsive Ξ^{-} interaction within pure neutron matter and this implies stiffer equations of state for neutron-rich matter including hyperons. Implications of the strong interaction for the modeling of neutron stars are discussed.

Switching On Depression and Potentiation in the Cerebellum

Long-term depression (LTD) and long-term potentiation (LTP) in the cerebellum are important for motor learning. However, the signaling mechanisms controlling whether LTD or LTP is induced in response to synaptic stimulation remain obscure. Using a unified model of LTD and LTP at the cerebellar parallel fiber-Purkinje cell (PF-PC) synapse, we delineate the coordinated pre- and postsynaptic signaling that determines the direction of plasticity. We show that LTP is the default response to PF stimulation above a well-defined frequency threshold. However, if the calcium signal surpasses the threshold for CaMKII activation, then an ultrasensitive "on switch" activates an extracellular signal-regulated kinase (ERK)-based positive feedback loop that triggers LTD instead. This postsynaptic feedback loop is sustained by another, trans-synaptic, feedback loop that maintains nitric oxide production throughout LTD induction. When full depression is achieved, an automatic "off switch" inactivates the feedback loops, returning the network to its basal state and demarcating the end of the early phase of LTD.

Visual detection of odorant geraniol enabled by integration of a human olfactory receptor into polydiacetylene/lipid nano-assembly

A new polydiacetylene lipid/human olfactory receptor nano-assembly was fabricated for the visual detection of an odorant for the first time. The assembly consisted of phospholipid-mixed polydiacetylenes (PDAs) and human olfactory receptors (hORs) in detergent micelles. To overcome the limitations of bioelectronic noses, hOR-embedded chromatic complexes (PDA/hORs) were developed, introducing PDAs that showed color and fluorescence transitions against various stimuli. The chromatic nanocomplexes reacted with target molecules, showing a fluorescence intensity increase in a dose-dependent manner and target selectivity among various odorants. As a result, a color transition of the assembly from blue to purple occurred, allowing the visual detection of the odorant geraniol. Through circular dichroism (CD) spectroscopy and a tryptophan fluorescence quenching method, the structural and functional properties of the hORs embedded in the complexes were confirmed. Based on this first work, future array devices, integrating multiple nano-assemblies, can be substantiated and utilized in environmental assessment and analysis of food quality.

Postsynaptic Stability and Variability Described by a Stochastic Model of Endosomal Trafficking

Neurons undergo dynamic processes of constitutive AMPA-type glutamate receptor (AMPAR) trafficking, such as the insertion and internalization of AMPARs by exocytosis and endocytosis, while stably maintaining synaptic efficacy. Studies using advanced imaging techniques have suggested that the frequency of these constitutive trafficking processes, as well as the number of AMPARs that are involved in a particular event highly fluctuate. In addition, mechanisms that trigger some forms of synaptic plasticity have been shown to include not only these processes but also additional fluctuating processes, such as the sorting of AMPARs to late endosomes (LEs). Thus, the regulation of postsynaptic AMPARs by the endosomal trafficking system appears to have superficially conflicting properties between the stability or organized control of plasticity and highly fluctuating or stochastic processes. However, it is not clear how the endosomal trafficking system reconciles and utilizes such conflicting properties. Although deterministic models have been effective to describe the stable maintenance of synaptic AMPAR numbers by constitutive recycling, as well as the involvement of endosomal trafficking in synaptic plasticity, they do not take stochasticity into account. In this study, we introduced the stochasticity into the model of each crucial machinery of the endosomal trafficking system. The specific questions we solved by our improved model are whether stability is accomplished even with a combination of fluctuating processes, and how overall variability occurs while controlling long-term synaptic depression (LTD). Our new stochastic model indeed demonstrated the stable regulation of postsynaptic AMPAR numbers at the basal state and during LTD maintenance, despite fast fluctuations in AMPAR numbers as well as high variability in the time course and amounts of LTD. In addition, our analysis suggested that the high variability arising from this stochasticity is beneficial for reproducing the relatively constant timing of LE sorting for LTD. We therefore propose that the coexistence of stability and stochasticity in the endosomal trafficking system is suitable for stable synaptic transmission and the reliable induction of synaptic plasticity, with variable properties that have been observed experimentally.

Azimuthal Anisotropy of Heavy-Flavor Decay Electrons in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

Angular correlations between heavy-flavor decay electrons and charged particles at midrapidity (|η|<0.8) are measured in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV. The analysis is carried out for the 0%-20% (high) and 60%-100% (low) multiplicity ranges. The jet contribution in the correlation distribution from high-multiplicity events is removed by subtracting the distribution from low-multiplicity events. An azimuthal modulation remains after removing the jet contribution, similar to previous observations in two-particle angular correlation measurements for light-flavor hadrons. A Fourier decomposition of the modulation results in a positive second-order coefficient (v_{2}) for heavy-flavor decay electrons in the transverse momentum interval 1.5<p_{T}<4  GeV/c in high-multiplicity events, with a significance larger than 5σ. The results are compared with those of charged particles at midrapidity and those of inclusive muons at forward rapidity. The v_{2} measurement of open heavy-flavor particles at midrapidity in small collision systems could provide crucial information to help interpret the anisotropies observed in such systems.

Thermal and Structural Stabilities of LixCoO2 cathode for Li Secondary Battery Studied by a Temperature Programmed Reduction

Temperature programmed reduction (TPR) method was introduced to analyze the structural change and thermal stability of LixCoO2 (LCO) cathode material. The reduction peaks of delithiated LCO clearly represented the different phases of LCO. The reduction peak at a temperature below 250 °C can be attributed to the transformation of CoO2–like to Co3O4–like phase which is similar reduction patterns of CoO2 phase resulting from delithiation of LCO structure. The 2nd reduction peak at 300~375 °C corresponds to the reduction of Co3O4–like phase to CoO–like phase. TPR results indicate the thermal instability of delithiated LCO driven by CoO2–like phase on the surface of the delithiated LCO. In the TPR kinetics, the activation energies (Ea) obtained for as-synthesized LCO were 105.6 and 82.7 kJ mol-1 for Tm_H1 and Tm_H2, respectively, whereas Ea for the delithiated LCO were 93.2, 124.1 and 216.3 kJ mol-1 for Tm_L1, Tm_L2 and Tm_L3, respectively. As a result, the TPR method enables to identify the structural changes and thermal stability of each phase and effectively characterize the distinctive thermal behavior between as-synthesized and delithiated LCO.