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Nonvolatile memory (NVM)‐based neuromorphic computing has been attracting considerable attention from academia and the industry. Although it is not completely successful yet, remarkable achievements have been reported pertaining to synaptic devices that can leverage NVM capable of storing multiple states. The analog synaptic devices performing computation similar to biological nerve systems are crucial in energy‐efficient analog neuromorphic computing systems. To use NVM as an analog synaptic device, researchers focus on improving device characteristics. Among various characteristics, the most challenging one is linearity and symmetry of synaptic weight update that is required for on‐chip training. In this regard, this review paper discusses recent synaptic device improvements focusing on novel schemes tailored for each NVM device to improve the linearity and symmetry. In addition to device‐level studies, recent research achievements are reviewed expanded up to chip‐level studies because in realizing neuromorphic hardware systems beyond a single synaptic device, several considerations and requirements are needed to confirm for high‐level design, and accordingly, cooptimize among synaptic devices, synapse arrays, electrical circuits, neural networks, algorithms, and implementation. Also, this review introduces various circuit and algorithmic approaches to compensate for the non‐ideality of the analog synaptic device. [ABSTRACT FROM AUTHOR]

Background: Computed tomography (CT)-guided transthoracic needle biopsy (TNB) could damage lung structures and may disseminate tumor cells into the airway, blood vessels, and pleural cavity, affecting post-operative outcomes. Several studies have investigated the effects of TNB on the prognosis of patients, but the effects remain unclear. This study aimed to investigate whether TNB increases the risk of recurrence of resected stage IA non-small cell lung cancer (NSCLC)., Methods: In this retrospective study, we enrolled 1,077 patients with stage IA NSCLC who underwent curative resection from 2010 to 2020. Recurrence risk factors were evaluated using Cox regression analyses. A multiple logistic regression model, including age, sex, smoking history, total tumor size, invasive tumor size, histology, histologic differentiation, lymphatic invasion, vascular invasion, perineural invasion, and the number of harvested lymph nodes (LNs), was used to calculate the propensity score., Results: According to the pre-operative TNB, patients were classified into the no-TNB (n=823) and TNB (n=190) groups. After propensity score matching analysis, 380 patients were included in the no-TNB group (1:2 matching). Multivariable Cox analysis revealed that pre-operative TNB was a negative prognostic factor in patients with surgically resected stage IA NSCLC [hazard ratio (HR), 3.15; 95% confidence interval (CI): 1.49-6.67; P=0.003]. The 5-year locoregional and overall recurrence-free survival (RFS) rates were significantly lower in the TNB group than in the no-TNB group (88.3% vs . 96.8%, P=0.001; and 84.2% vs . 93.7%, P=0.02, respectively)., Conclusions: For patients with stage IA NSCLC, pre-operative TNB was a negative prognostic factor for recurrence. Surgical diagnosis and treatment without pre-operative tissue diagnosis may be considered first in patients with clinically early lung cancer., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-419/coif). The authors have no conflicts of interest to declare., (2024 Journal of Thoracic Disease. All rights reserved.)

Background: Unexpected conversion to thoracotomy during planned video-assisted thoracoscopic surgery (VATS) can lead to poor outcomes and comparatively high morbidity. This study was conducted to assess preoperative risk factors associated with unexpected thoracotomy conversion and to develop a risk scoring model for preoperative use, aimed at identifying patients with an elevated risk of conversion., Methods: A retrospective analysis was conducted of 1,506 patients who underwent surgical resection for non-small cell lung cancer. To evaluate the risk factors, univariate analysis and logistic regression were performed. A risk scoring model was established to predict unexpected thoracotomy conversion during VATS of the lung, based on preoperative factors. To validate the model, an additional cohort of 878 patients was analyzed., Results: Among the potentially significant clinical variables, male sex, previous ipsilateral lung surgery, preoperative detection of calcified lymph nodes, and clinical T stage were identified as independent risk factors for unplanned conversion to thoracotomy. A 6-point risk scoring model was developed to predict conversion based on the assessed risk, with patients categorized into 4 groups. The results indicated an area under the receiver operating characteristic curve of 0.747, with a sensitivity of 80.5%, specificity of 56.4%, positive predictive value of 1.8%, and negative predictive value of 91.0%. When applied to the validation cohort, the model exhibited good predictive accuracy., Conclusion: We successfully developed and validated a risk scoring model for preoperative use that can predict the likelihood of unplanned conversion to thoracotomy during VATS of the lung.

Background: Visceral pleural invasion (VPI) is a poor prognostic factor that contributes to the upstaging of early lung cancers. However, the preoperative assessment of VPI presents challenges. This study was conducted to examine intraoperative pleural carcinoembryonic antigen (pCEA) level and maximum standardized uptake value (SUVmax) as predictive markers of VPI in patients with clinical T1N0M0 lung adenocarcinoma., Methods: A retrospective review was conducted of the medical records of 613 patients who underwent intraoperative pCEA sampling and lung resection for non-small cell lung cancer. Of these, 390 individuals with clinical stage I adenocarcinoma and tumors ≤30 mm were included. Based on computed tomography findings, these patients were divided into pleural contact (n=186) and non-pleural contact (n=204) groups. A receiver operating characteristic (ROC) curve was constructed to analyze the association between pCEA and SUVmax in relation to VPI. Additionally, logistic regression analysis was performed to evaluate risk factors for VPI in each group., Results: ROC curve analysis revealed that pCEA level greater than 2.565 ng/mL (area under the curve [AUC]=0.751) and SUVmax above 4.25 (AUC=0.801) were highly predictive of VPI in patients exhibiting pleural contact. Based on multivariable analysis, pCEA (odds ratio [OR], 3.00; 95% confidence interval [CI], 1.14-7.87; p=0.026) and SUVmax (OR, 5.25; 95% CI, 1.90-14.50; p=0.001) were significant risk factors for VPI in the pleural contact group., Conclusion: In patients with clinical stage I lung adenocarcinoma exhibiting pleural contact, pCEA and SUVmax are potential predictive indicators of VPI. These markers may be helpful in planning for lung cancer surgery.

Introduction: The conventional technique for pectus excavatum repair was pushing up the depressed chest wall by turning over the convexity of the bent pectus bar. We developed a new concept in which a total crane lift was used as the source of power to elevate the depressed sternum without using pectus bar leverage. This study aims to verify the efficacy of exclusively crane-powered pectus excavatum repair in recent years., Methods: Among the 3622 pectus deformity repairs since 1999, 691 cases repaired with the total crane power between 2017 and 2022 were enrolled. The mean age was 12.0 years (3-45). The operative technique involved wire/screw crane elevation of the sternum, the entire chest wall remodeling with the cross or parallel bars, the bridge/claw bar fixations, and other adjunctive techniques. Outcome analysis included morphological variations, patterns of pectus bar placement, and complication rates., Results: The crane technique and pectoscopy (100%) were used. The bar placements were parallel (22.0%) and cross-bar (47.5%). The bar fixations were the claw fixators for a single bar (30.5%) and the bridge plates for multiple bars (69.5%). The flare-buster and magic strings were liberally used. No serious complications or catastrophic events occurred, but minor complications occurred in 16.9%: pneumothorax in 7.4% (51), pleural effusion in 1.6% (11), and wound problems in 0.4% (3). There was no case of bar displacement., Discussion: The crane-powered pectus excavatum repair showed excellent results with minimal complications and no bar displacement. This innovative approach, part of the NeoPectus surgery, represents a significant advancement in correcting pectus excavatum deformities by utilizing a crane machine to elevate the chest wall., Competing Interests: Consultant of Primemed, Inc., (© 2023 Park, Rim and Yoon.)

Background: The beneficial effect of preserved superior segment (S6) after common basal segmentectomy remains unknown. We aimed to evaluate the effect of preserved superior segment on lung volume and function., Methods: Among 671 segmentectomies and 2,249 lobectomies for clinical stage IA lung cancer between 2004 and 2020, 48 patients who received thoracoscopic common basal segmentectomy were included and compared with 96 patients who received thoracoscopic lower lobectomy after propensity score matching. The variables analyzed were age, sex, comorbidity, smoking history, preoperative forced expiratory volume in one second (FEV1), clinical T stage, histology, and tumor location. Lung volume was assessed using a three-dimensional (3D) computed tomography (CT)-based volumetric method., Results: There were no significant differences between common basal segmentectomy (segmentectomy group) and lower lobectomy (lobectomy group) (4,183.8±1,114.9 versus 3,850.7±1,132.1 mL; P=0.10) in terms of preoperative CT-measured total lung volume. At the immediate postoperative median follow-up period (6.4 months), the reduced percentage of CT-measured total lung volume in the segmentectomy group was significantly larger than that in the lobectomy group (-16.2% versus -6.5%; P=0.004). The percentage of CT-measured contralateral lung volume expansion in the segmentectomy group was significantly smaller than that in the lobectomy group (-0.7% versus +8.9%; P=0.006). At the last median follow-up period (43.1 months), the reduced percentage of CT-measured total lung volume in the segmentectomy group remained larger than that in the lobectomy group (-13.0% versus -3.0%; P=0.01). The reduced percentage of postoperative FEV1 in the segmentectomy group did not differ from that in the lobectomy group (-9.9% versus -11.5%, P=0.63)., Conclusions: Preserving the superior segment might not provide beneficial effect on the preservation of postoperative lung volume and function after common basal segmentectomy compared with lower lobectomy., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-791/coif). The authors have no conflicts of interest to declare., (2023 Journal of Thoracic Disease. All rights reserved.)

Background: The prognostic significance of extranodal extension (ENE) remains unclear in patients with pathologic N1 (pN1) non-small-cell lung cancer (NSCLC) undergoing surgery. We evaluated the prognostic impact of ENE in patients with pN1 NSCLC., Methods: From 2004 to 2018, we retrospectively analyzed the data of 862 patients with pN1 NSCLC who underwent lobectomy and more (lobectomy, bilobectomy, pneumonectomy, sleeve lobectomy). According to their resection status and the presence of ENE, patients were classified into R0 without ENE (pure R0) (n=645), R0 with ENE (R0-ENE) (n=130), and incomplete resection (R1/R2) groups (n=87). The primary and secondary endpoints were 5-year overall survival (OS) and recurrence-free survival (RFS), respectively., Results: The prognosis of the R0-ENE group was significantly worse than the pure R0 group for both OS (5-year rate: 51.6% vs. 65.4%, P=0.008) and RFS (44.4% vs. 53.0%, P=0.04). According to the recurrence pattern, a difference of RFS was found only for distant metastasis (55.2% vs. 65.0%, P=0.02). The multivariable Cox analysis revealed that the presence of ENE was a negative prognostic factor in patients who did not undergo adjuvant chemotherapy [hazard ratio (HR) =1.58; 95% confidence interval (CI): 1.06-2.36; P=0.03], but it was not in those with adjuvant chemotherapy (HR =1.20; 95% CI: 0.80-1.81; P=0.38)., Conclusions: For patients with pN1 NSCLC, the presence of ENE was a negative prognostic factor for both OS and RFS, regardless of resection status. The negative prognostic effect of ENE was significantly associated with an increase in distant metastasis and was not observed in patients who underwent adjuvant chemotherapy., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-150/coif). SC serves as an unpaid editorial board member of Journal of Thoracic Disease from October 2022 to September 2024. The other authors have no conflicts of interest to declare., (2023 Journal of Thoracic Disease. All rights reserved.)

Background: Several factors, such as the degree of target vessel stenosis, are known to be associated with radial artery (RA) graft patency in coronary artery bypass grafting (CABG). There is a lack of data regarding the effect of the RA proximal configuration (aortic anastomosis versus T-anastomosis). This study evaluated the effects of the RA proximal configuration on the patency rate and clinical outcomes after CABG., Methods: We conducted a retrospective study, analyzing 328 patients who had undergone CABG with an RA graft. We divided the patients into 2 groups. The primary endpoint was RA patency and the secondary endpoints were overall mortality and major adverse cardiac and cerebrovascular events (MACCE). We performed a propensity score-matched comparison., Results: Aorta-RA anastomosis was performed in 275 patients, whereas the rest of the 53 patients received T-RA anastomosis. The mean age was 67.3±8.7 years in the T-RA anastomosis group and 63.8±9.5 years in the aorta-RA anastomosis group (p=0.02). The mean follow-up duration was 5.13±3.07 years. Target vessel stenosis ≥70% (hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.20-0.91; p=0.03) and T-RA anastomosis configuration (HR, 2.34; 95% CI, 1.01-5.19; p=0.04) were significantly associated with RA occlusion in the multivariable analysis. However, T-RA anastomosis was not associated with higher risks of overall mortality and MACCE following CABG (p=0.30 and p=0.07 in the matched group, respectively)., Conclusion: Aorta-RA anastomosis showed a superior patency rate compared to T-RA anastomosis. However, the RA proximal anastomosis configuration was not associated with mortality or MACCE.

This paper proposes a novel signal quality assessment method for quasi-periodic cardiovascular signals, chiefly focus on the photoplethysmogram (PPG). The proposed method utilizes the fact that most cardiovascular signals are slowly time varying and thus morphological aspects of the two adjacent beats are almost identical. In order to implement this idea, the method first identifies pulse onset to divide the signal into several segments each of which contains one period of the signal. The segmented pulse signals having different pulse durations are then temporarily normalized by resampling them at a specific rate. Finally, the quality of the signals is evaluated as the signal similarity between the two adjacent segments. Optimal thresholds for the classification between high-and low-quality PPG signals are determined using the equal training sensitivity and specificity criterion. The proposed method is evaluated using a database where PPG signals are collected during a variety of activities such as cycling exercise. It attains a sensitivity of 97.9%, a specificity of 85.3%, and an accuracy of 93.8%, compared to manually annotated results. The promising results indicate that the proposed method is affordable to simply determine the quality of quasi-periodic cardiovascular signals, particularly PPG signals. In addition, based on the quasi-periodic characteristics of cardiovascular signals, the proposed method can also be used to indicate the reliability and the availability of the collected signals.

Wearable devices for body-status monitoring require various signal processing such as ambient noise filtering and signal quality evaluation. While wearable devices are very limited in resource, conventional noise filtering and signal quality evaluating methods consume considerable amount of processing power. Moreover, these conventional methods are not suitable for processing bio-signals in terms of its performance. In this paper, we propose a novel method of preprocessing bio-signals. This preprocessing method includes distortionless noise filtering and signal quality estimation, where both parts are basically based on a simple combination of multiple low pass IIR filters.

Wearable devices are becoming a natural and economic means to gather biometric data from end users. The massive amount of information that they will provide, unimaginable until a few years ago, owns an immense potential for applications such as continuous monitoring for personalized healthcare and use within fitness applications. Wearables are however heavily constrained in terms of amount of memory, transmission capability and energy reserve. This calls for dedicated, lightweight but still effective algorithms for data management. This paper is centered around lossy data compression techniques, whose aim is to minimize the amount of information that is to be stored on their onboard memory and subsequently transmitted over wireless interfaces. Specifically, we analyze selected compression techniques for biometric signals, quantifying their complexity (energy consumption) and compression performance. Hence, we propose a new class of codebook-based (CB) compression algorithms, designed to be energy efficient, online and amenable to any type of signal exhibiting recurrent patterns. Finally, the performance of the selected and the new algorithm is assessed, underlining the advantages offered by CB schemes in terms of memory savings and classification algorithms.