Enhanced Switching Pattern to Improve Cell Balancing Performance in Active Cell Balancing Circuit using Multi-winding Transformer

Cell balancing performance is an important factor in determining the operational efficiency of the active cell balancing circuit. Thus, this study approached this need by developing an enhanced switching pattern. The circuit is designed to transfer energy between arbitrary source and target cells. It has been operated in flyback and buck-boost modes according to the position of the source and target cells. In this circuit, the coupling coefficient of the transformer considerably affects the balancing performance of the flyback operation. The energy transferred to the non-target cell is increased by the low-coupling coefficient due to the leakage inductance. Therefore, the high energy transfer ratio cannot be achieved using conventional switching patterns. In this paper, a new flyback switching pattern is proposed, which can minimize the effect of the coupling coefficient in the cell balancing operation. The proposed switching pattern uses the cells which do not participate in the balancing process to control the voltage applied to each winding, which results in a high energy transfer ratio irrespective of the coupling coefficient. In addition, an enhanced operating method has been proposed to improve the cell balancing speed by reducing the energy transfer path in specific cell conditions. The performance of the proposed switching pattern was verified in a 15 W cell balancing circuit

CardioGuard: A Brassiere-based Reliable ECG Monitoring Sensor System for Supporting Daily Smartphone Healthcare Applications

We propose CardioGuard, a brassiere-based reliable electrocardiogram (ECG) monitoring sensor system, for supporting daily smartphone healthcare applications. It is designed to satisfy two key requirements for user-unobtrusive daily ECG monitoring: reliability of ECG sensing and usability of the sensor. The system is validated through extensive evaluations. The evaluation results showed that the CardioGuard sensor reliably measure the ECG during 12 representative daily activities including diverse movement levels; 89.53% of QRS peaks were detected on average. The questionnaire-based user study with 15 participants showed that the CardioGuard sensor was comfortable and unobtrusive. Additionally, the signal-to-noise ratio test and the washing durability test were conducted to show the high-quality sensing of the proposed sensor and its physical durability in practical use, respectively

Sinabro: A Smartphone-Integrated Opportunistic Electrocardiogram Monitoring System

In our preliminary study, we proposed a smartphone-integrated, unobtrusive electrocardiogram (ECG) monitoring system, Sinabro, which monitors a user’s ECG opportunistically during daily smartphone use without explicit user intervention. The proposed system also monitors ECG-derived features, such as heart rate (HR) and heart rate variability (HRV), to support the pervasive healthcare apps for smartphones based on the user’s high-level contexts, such as stress and affective state levels. In this study, we have extended the Sinabro system by: (1) upgrading the sensor device; (2) improving the feature extraction process; and (3) evaluating extensions of the system. We evaluated these extensions with a good set of algorithm parameters that were suggested based on empirical analyses. The results showed that the system could capture ECG reliably and extract highly accurate ECG-derived features with a reasonable rate of data drop during the user’s daily smartphone use

Longitudinal Patterns in Antithrombotic Therapy in Patients with Atrial Fibrillation after Percutaneous Coronary Intervention in the Non-Vitamin K Oral Anticoagulant Era:A Nationwide Population-Based Study

We investigated whether longitudinal patterns in antithrombotic therapy have changed after the introduction of non-vitamin K oral anticoagulants (NOACs) in patients with atrial fibrillation (AF) who underwent percutaneous coronary intervention (PCI). Using a claims database of the Korean AF population who underwent PCI between 2012 and 2016 (n = 18,691), we analyzed prescription records of oral anticoagulants (OACs) and antiplatelets at 3-month intervals over 2 years after PCI. The study population was stratified (pre-NOAC, transition, and NOAC era) using time-periods of NOAC introduction in Korea and an expansion of reimbursement for NOAC in AF as indicators. The overall rates of OAC were low at baseline (24.9%, 26.9%, and 35.2% in pre-NOAC, transition, and NOAC era, respectively), contrary to high rates of dual antiplatelet therapy (DAPT) (73.3%, 71.4%, and 63.6%). However, OAC prescription rates were increased at 1-year (18.5%, 22.5%, and 31.6%), and 2-year follow-up (17.8%, 24.2%, and 31.8%) from pre-NOAC to NOAC era. In NOAC era, 63.5% of baseline OAC prescriptions comprised NOAC, of which 96.4% included triple therapy with DAPT. Over 2 years, we observed increasing rates of double therapy with a single antiplatelet (18.3% and 20.0% at 1- and 2-year follow-up) and OAC monotherapy (2.7% and 8.9% at 1- and 2-year follow-up)

Net clinical benefit of antithrombotic therapy for atrial fibrillation patients with stable coronary artery disease

OBJECTIVES: To compare the net clinical benefit of oral anticoagulant (OAC) monotherapy to OAC plus single antiplatelet therapy (SAPT) in patients with atrial fibrillation (AF) and stable coronary artery disease (CAD) at 1- and 3-year after percutaneous coronary intervention (PCI). BACKGROUND: It has not been studied whether the net clinical benefit of the antithrombotic treatment options differs depending on the elapsed time from the index PCI. METHODS: Using the Korean nationwide claims database, we included AF patients who underwent PCI from 2009 to 2019 and constructed two cohorts: 1- and 3-year after PCI. In each cohort, the baseline characteristics of two groups were balanced using propensity score weighting. Ischemic stroke, myocardial infarction, major bleeding, and composite clinical outcomes were analyzed. RESULTS: Among patients with 1-year after PCI, OAC monotherapy (n = 678), and OAC plus SAPT (n = 3,159) showed comparable results for all clinical outcomes. In patients with 3-year after PCI, OAC monotherapy (n = 1,038) and OAC plus SAPT (n = 2,128) showed comparable results for ischemic stroke and myocardial infarction, but OAC monotherapy was associated with a lower risk of composite clinical outcomes (HR 0.762, 95% CI 0.607–0.950), mainly driven by the reduction of major bleeding risk (HR 0.498, 95% CI 0.345–0.701). CONCLUSION: Oral anticoagulant monotherapy may be a comparable choice for patients with AF and stable CAD compared to OAC plus SAPT. In patients with stable CAD more than 3-year after index PCI, OAC monotherapy would be a better choice, being associated with less major bleeding and a positive net clinical benefit

Neutrophil-to-lymphocyte ratio as a predictor of in-hospital complications and overall mortality in Takotsubo syndrome preceded by physical triggers

Background Takotsubo syndrome (TTS) with physical triggers has worse short- and long-term clinical courses than those with emotional triggers. However, predictive factors associated with poor outcomes of TTS with physical triggers are unknown. Methods We included 231 patients identified as TTS preceded by physical triggers at two tertiary referral hospitals from 2010 to 2019. In-hospital complications (IHC)—a composite of malignant arrhythmia, need for mechanical circulatory support or mechanical ventilation, and in-hospital death—and overall mortality were retrospectively reviewed. The associations with clinical features were evaluated by multivariable logistic and Cox regression analyses. Results The mean age was 69.3 ± 11.6years, and 85 (36.8%) were male. The in-hospital complications rate was 46.8%. During a median follow-up of 883days, 96 (41.6%) had died, and overall mortality was 13.6% per patient-year. Higher neutrophil-to-lymphocyte ratio (NLR) was associated with a higher risk of IHC (area under the receiver operating characteristic curve = 0.73; positive and negative predictive value = 60.9% and 67.2% for NLR ≤ 12); odds ratio (OR) with 95% confidence interval (CI) was 1.03 (1.01–1.05), p = 0.010. Subsequently, higher NLR was also related to a greater risk of overall mortality; patients with high NLR (NLR > 12) exhibited poor long-term survival than those with low NLR (NLR ≤ 5): hazard ratio (95% CI), 3.70 (1.72–7.94) with p < 0.001. Conclusions A high NLR at initial presentation is associated with an increased risk of IHC and overall mortality in TTS preceded by physical triggers. Given that the treatment of TTS is mainly supportive, intensive monitoring with careful follow-up would be warranted in patients with high NLR.This study was funded by SNUBH Research Fund [Grant No. 14-2015-029]

CD82/KAI1 Maintains the Dormancy of Long-Term Hematopoietic Stem Cells through Interaction with DARC- Expressing Macrophages

Hematopoiesis is regulated by crosstalk between long-term repopulating hematopoietic stem cells (LT-HSCs) and supporting niche cells in the bone marrow (BM). Here, we examine the role of CD82/ KAI1 in niche-mediated LT-HSC maintenance. We found that CD82/ KAI1 is expressed predominantly on LT-HSCs and rarely on other hematopoietic stem-progenitor cells (HSPCs). In Cd82 +/-/+/- mice, LTHSCs were selectively lost as they exited from quiescence and differentiated. Mechanistically, CD82based TGF-b1/ Smad3 signaling leads to induction of CDK inhibitors and cell-cycle inhibition. The CD82 binding partner DARC/ CD234 is expressed on macrophages and stabilizes CD82 on LT-HSCs, promoting their quiescence. When DARC + BMmacrophages were ablated, the level of surface CD82 on LT-HSCs decreased, leading to cell-cycle entry, proliferation, and differentiation. A similar interaction appears to be relevant for human HSPCs. Thus, CD82 is a functional surface marker of LT-HSCs that maintains quiescence through interaction with DARC-expressing macrophages in the BM stem cell niche.113525Ysciescopu