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BackgroundChronic obstructive pulmonary disease (COPD) is one of the major morbidities in public health, and the use of mHealth technology for rehabilitation of patients with COPD can help increase physical activity and ameliorate respiratory symptoms. ObjectiveThis study aimed to develop a comprehensive rehabilitation management platform to improve physical activity and quality of life in patients with COPD. MethodsThe study comprised the following 2 stages: (1) a pilot stage in which a prototype app was developed; and (2) a fully-fledged platform development stage in which 2 apps and 1 COPD patient monitoring website were developed. We conducted a randomized clinical trial to investigate the efficacy of the apps developed in the second stage of the study. In addition, two 12-week exercise regimens (fixed and fixed-interactive) were tested for the trial. The clinical parameters of the respiratory function and patient global assessment (PGA) of the app were obtained and analyzed. Notably, Android was the chosen operating system for apps. ResultsWe developed 2 COPD rehabilitation apps and 1 patient monitoring website. For the clinical trial, 85 patients were randomized into the following 3 groups: 57 were allocated to the 2 intervention groups and 28 to the control group. After 6 weeks, the COPD assessment test scores were significantly reduced in the fixed group (P=.01), and signs of improvement were witnessed in the fixed-interactive group. In addition, the PGA score was moderate or high in all aspects of the user experience of the apps in both intervention groups. ConclusionsA well-designed mobile rehabilitation app for monitoring and managing patients with COPD can supplement or replace traditional center-based rehabilitation programs and achieve improved patient health outcomes. Trial RegistrationClinicalTrials.gov NCT03432117; https://clinicaltrials.gov/ct2/show/NCT03432117 (Archived by WebCite at http://www.webcitation.org/71Yp0P64a)

This study presents findings indicating that the ferroelectric tunnel junction (FTJ) or resistive random-access memory (RRAM) in one cell can be intentionally selected depending on the application. The HfAlO film annealed at 700 °C shows stable FTJ characteristics and can be converted into RRAM by forming a conductive filament inside the same cell, that is, the process of intentionally forming a conductive filament is the result of defect generation and redistribution, and applying compliance current prior to a hard breakdown event of the dielectric film enables subsequent RRAM operation. The converted RRAM demonstrated good memory performance. Through current–voltage fitting, it was confirmed that the two resistance states of the FTJ and RRAM had different transport mechanisms. In the RRAM, the 1/f noise power of the high-resistance state (HRS) was about ten times higher than that of the low-resistance state (LRS). This is because the noise components increase due to the additional current paths in the HRS. The 1/f noise power according to resistance states in the FTJ was exactly the opposite result from the case of the RRAM. This is because the noise component due to the Poole–Frenkel emission is added to the noise component due to the tunneling current in the LRS. In addition, we confirmed the potentiation and depression characteristics of the two devices and further evaluated the accuracy of pattern recognition through a simulation by considering a dataset from the Modified National Institute of Standards and Technology. [ABSTRACT FROM AUTHOR]

This study presents a preliminary exploration of thermally oxidized TaOx-based memristors and their potential as artificial synapses. Unlike the 10-min annealed devices, which display instability due to current overshoots, the 5-min annealed device exhibits stable resistive switching, retention, and endurance characteristics. Moreover, our memristor showcases synaptic behaviors encompassing potentiation, depression, spike-timing-dependent plasticity, and excitatory postsynaptic currents. This synaptic emulation holds tremendous promise for applications in neuromorphic computing, offering the opportunity to replicate the adaptive learning principles observed in biological synapses. In addition, we evaluate the device's suitability for pattern recognition within a neural network using the modified National Institute of Standards and Technology dataset. Our assessment reveals that the Pt/TaOx/Ta memristor with an oxidized insulator achieves outstanding potential manifested by an accuracy of 93.25% for the identical pulse scheme and an impressive accuracy of 95.42% for the incremental pulse scheme. [ABSTRACT FROM AUTHOR]

Are highly specialized hikers really more likely to behave in a pro-environmental manner? By discussing a negative linkage between recreation specialization and pro-environmental behavior, this study tackles a narrowly optimistic view that specialized hikers are always likely to behave pro-environmentally. We examined survey data from South Korean hikers and found that while recreation specialization does not significantly affect attitudes, it negatively affects perceived behavioral control. Further, all types of pro-environmental behavior were significantly impacted by their attitude, but only one pro-environmental behavior (i.e., following designated trails) was strongly impacted by perceived behavioral control. By synthesizing our findings with current literature, we suggest comprehensively evaluating all three motivational factors—self-interest, prosocial, and affective motivations—to predict pro-environmental behavior. [ABSTRACT FROM AUTHOR]

The use of Hf0.5Zr0.5O2 (HZO) films within hafnia‐based ferroelectric tunnel junctions (FTJ) presents a promising avenue for next‐generation non‐volatile memory devices. HZO exhibits excellent ferroelectric properties, ultra‐thinness, low power consumption, nondestructive readout, and compatibility with silicon devices. In this study, Mo/HZO/n+ Si devices are investigated, incorporating a 1 nm HfO2 dielectric layer at the top and bottom of the HZO ferroelectric layer. Comparing the FTJ device configurations, it is observed that the metal‐ferroelectric‐dielectric‐semiconductor (MFIS) outperforms the metal‐dielectric‐ferroelectric‐semiconductor (MIFS) in terms of ferroelectricity, displaying a high 2Pr value of ≈69 µC cm−2. Additionally, MFIS exhibits lower leakage current, higher tunneling electro‐resistance ratio, and a thin dead layer during short pulse switching, as confirmed through DC double sweeping of I−V characteristics. The modified half‐bias scheme demonstrates a maximum array size of 191 for MFIS, showcasing its superior performance over MIFS. Synaptic characteristics, including potentiation, depression, paired‐pulse facilitation, spike‐rate‐dependent plasticity, and excitatory postsynaptic current, are measured using MFIS, highlighting its outstanding ferroelectric properties. As a physical reservoir, the FTJ device implements 16 states of 4 bits in reservoir computing. Finally, pattern recognition using a deep learning neural network achieves high accuracy with using the Modified National Institute of Standards and Technology dataset. [ABSTRACT FROM AUTHOR]

Background and Objective: When multiple complex air pollutants are combined in real‐world settings, the reliability of estimating the effect of a single pollutant is questionable. This study aimed to investigate the combined effects of changes in air pollutants on small airway dysfunction (SAD). Methods: We analysed Korea National Health and Nutrition Examination Survey (KNHANES) V–VIII database from 2010 to 2018 to elucidate the associations between annual changes in air pollutants over a previous 5‐year period and small airway function. We estimated the annual concentrations of five air pollutants: NO2, O3, PM2.5, SO2 and CO. Forced expiratory flow between 25% and 75% of vital capacity (FEF25%–75%) <65% was defined as SAD. Using the quantile generalized‐Computation (g‐Computation) model, the combined effect of the annual changes in different air pollutants was estimated. Results: A total of 29,115 individuals were included. We found significant associations between SAD and the quartiles of annual changes in NO2 (OR = 1.10, 95% CI = 1.08–1.12), O3 (OR = 1.03, 95% CI = 1.00–1.05), PM2.5 (OR = 1.03, 95% CI = 1.00–1.05), SO2 (OR = 1.04, 95% CI = 1.02–1.08) and CO (OR = 1.16, 95% CI = 1.12–1.19). The combined effect of the air pollutant changes was significantly associated with SAD independent of smoking (OR = 1.31, 95% CI = 1.26–1.35, p‐value <0.001), and this trend was consistently observed across the entire study population and various subgroup populations. As the estimated risk of SAD, determined by individual‐specific combined effect models, increased and the log odds for SAD increased linearly. Conclusion: The combined effect of annual changes in multiple air pollutant concentrations were associated with an increased risk of SAD. [ABSTRACT FROM AUTHOR]

This study implements a highly uniform 3D vertically stack resistive random‐access memory (VRRAM) with a four‐layer contact hole structure. The fabrication process of a four‐layer VRRAM is demonstrated, and its physical and electrical properties are thoroughly examined. X‐ray photoelectron spectroscopy and transmission electron microscopy are employed to analyze the chemical distribution and physical structure of the VRRAM device. Multilevel capability, reliable endurance (>104 cycles), and retention (104 s) are successfully obtained. Synaptic memory plasticity, such as spike time‐dependent plasticity, spike rate‐dependent plasticity, excitatory post‐synaptic current, paired‐pulse facilitation, and long‐term potentiation and depression is presented. Finally, the vector‐matrix multiplication (VMM) operation is conducted on a 4 × 12 VRRAM array, according to the low resistance state ratio. It is ascertained that the accuracy drop, which can occur due to VMM error, can be limited to a decrease of less than 0.44% point. Utilizing the high‐density, multilevel, and biological characteristics of VRRAM, it is possible to implement high‐performance neuromorphic systems that require densely integrated synaptic devices. [ABSTRACT FROM AUTHOR]

Background: Sarcopenia is a risk factor for pneumonia in the elderly, and the timed up-and-go test (TUG) can be used as a screening tool for sarcopenia in this population. This study aimed to evaluate the association between TUG test results and future pneumonia or ventilator care. Materials and methods: From the National Health Insurance Service-Senior Cohort database, we identified 19,804 people without neurological diseases who underwent the TUG test in the National Screening Program for Transitional Ages at the age of 66 years during 2007–2008. Gait abnormality was defined as taking 10 s or longer to perform the TUG test. Pneumonia occurrence was defined using the International Classification of Diseases 10th Revision (ICD-10) code for pneumonia (J12–J18, J69), and ventilator care was defined by procedure codes (M5830, M5850, M5867, M5858, M5860, M5859) according to the Healthcare Common Procedure Coding system codes from 2007 to 2015. Results: The mean follow-up period was 7.4 years (standard error, SE 0.02). The incidence rates of pneumonia in the normal and slow TUG groups were 38 and 39.5/1000 person-years, respectively. The slow TUG group did not show a higher risk of pneumonia (adjusted hazard ratio [aHR], 1.042; 95% confidence interval [95% CI], 0.988–1.107]). Regarding ventilator care, the incidence was 4.7 and 5.2 cases per 1,000 person-years in the normal and slow TUG groups, respectively. Slow TUG groups also did not show an increased risk of ventilator occurrence (aHR, 1.136, [95% CI = 0.947–1.363]). Conclusion: The TUG test result was not associated with future pneumonia or ventilator care and may not be useful for predicting pneumonia in community-dwelling elderly individuals. Further studies are needed to identify additional functional tools for sarcopenia associated with future pneumonia occurrences. [ABSTRACT FROM AUTHOR]

Background: Comorbidities of chronic obstructive pulmonary disease (COPD) influence clinical characteristics and prognosis. Objectives: This study compared the clinical characteristics and exacerbation rate of COPD according to the presence of depression or anxiety. Design: This study used data from The Korea COPD Subgroup Study (KOCOSS) cohort, a nationwide prospective cohort from 54 medical centers, between April 2012 and 2019. Methods: Depression and anxiety were diagnosed with the Beck Depression Inventory and Beck Anxiety Inventory. Negative binomial regression analysis was performed to analyze the frequency of exacerbations in depressed patients and anxiety. Differences in lung function trajectory according to presence of depression/anxiety were analyzed using a linear mixed model. Results: In all, 2147 patients were enrolled. Depressed patients or anxiety had lower lung function, higher modified Medical Research Council (mMRC) grade, St. George Respiratory Questionnaire (SGRQ) score, and COPD assessment test score, and higher rates of exacerbation in the past year than those without depression/anxiety. Depressed patients had a higher frequency of moderate to severe exacerbations [Incidence Rate Ratio (IRR): 1.57, CI: 1.17–2.11, p = 0.002] and those with anxiety had higher frequencies of moderate to severe (IRR: 1.52, CI: 1.03–2.27, p = 0.038) and severe exacerbations (IRR: 2.13, CI: 1.09–4.15, p = 0.025) during 1-year follow-up compared to those without these comorbidities. The differences in the change in annual forced expiratory volume in 1 seconds (FEV1) over 3 years according to the presence of depression or anxiety were not statistically significant. Conclusion: Depressed and anxious patients showed increased respiratory symptoms and exacerbation rate as well as reduced health-related quality of life, whereas there were no significant differences in changes in lung function between groups with and without depression/anxiety. [ABSTRACT FROM AUTHOR]

Background: The Rome proposal provides an objective assessment tool for severity of acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) but requires validation. Objectives: We aimed to evaluate the predictive performance of the Rome proposal in patients with AE-COPD. Design: This observational study assessed the patients who visited the emergency room (ER) or were hospitalized due to AE-COPD between January 2010 and December 2020. Methods: We compared the performance of the Rome Proposal with that of the DECAF score or GesEPOC 2021 criteria in predicting intensive care unit (ICU) admission, need for non-invasive ventilation (NIV) or invasive mechanical ventilation (IMV), and in-hospital mortality. Results: A total of 740 events of ER visit or hospitalization due to AE-COPD were reviewed and classified into mild (30.9%), moderate (58.6%), or severe (10.4%) group according to the Rome proposal. The severe group had a higher rate of ICU admission, required more NIV or IMV, and had a higher in-hospital mortality than the mild and moderate groups. The predictive performance of the Rome proposal was significantly better for ICU admission [area under the receiver operating characteristic curve (AU-ROC) = 0.850 versus 0.736, p = 0.004] and need for NIV or IMV (AU-ROC = 0.870 versus 0.770, p = 0.004) than that of the GesEPOC 2021 criteria but better than that of the DECAF score only in female patients. There was no significant difference in predicting the in-hospital mortality between the Rome proposal and DECAF score or GesEPOC 2021 criteria. Conclusion: External validation of the Rome Proposal in Korean patients demonstrated excellent performance for ICU admission and need for NIV or IMV and an acceptable performance for in-hospital mortality. [ABSTRACT FROM AUTHOR]

In this work, we analyze a resistive switching random access memory (RRAM) device with the metal–insulator–metal structure of Al/αTiOx/Al. The transport mechanism of our RRAM device is trap-controlled space-charge limited conduction, which does not change during the endurance test. As the number of resistive switching (RS) cycles increases, the current in the low-resistance state (LRS) does not change significantly. In contrast, degradation in the high-resistance state (HRS) is noticeably evident. According to the RS cycle, the current shift fits well with the stretched-exponential equation. The normalized noise power spectral density (Si/I2) measured in the HRS is an order of magnitude higher than that in the LRS owing to the difference in the degree of trap occupancy, which is responsible for the transition of resistance states. During the consecutive RS, the Si/I2 in the HRS rapidly decreases for approximately 100 cycles and then saturates. In contrast, in the LRS, the Si/I2 does not change significantly. Here we propose a model associated with the endurance degradation of the experimental device, and the model is verified with a 1 / f noise measurement. [ABSTRACT FROM AUTHOR]

Fossil fuels are associated with problems such as resource depletion and pollution, necessitating the exploration of alternatives. Giant miscanthus (Miscanthus × giganteus Greef et Deu), a perennial that can be harvested yearly, requires a low production energy input. It has less ash content and high heat efficiency and has attracted attention as an energy source. An on-site processing equipment, powered via a tractor and equipped with a chipper and a two-stage compression roller, was developed that can harvest 1000 kg of giant miscanthus per hour and simultaneously produce compressed pellets eliminating unnecessary processes such as transportation and processing. With its use, 33–74.5 kWh/t of electrical energy can be saved by producing pellets. The changes in moisture content between the produced compressed pellets and two samples of the ground product were measured immediately before compression for 24 h at relative humidity ranging from 65% to 80%. The moisture content was 6% initially; it ranged from 6.71% to 7.81% in compressed pellets, depending on the conditions, and from 7.44% to 9.82% in the ground sample immediately before compression, indicating the effect of the physical form of the biomass and humidity in the environment. The possible storage period (while maintaining the moisture content at 8–10% for optimal biofuel efficiency based on the measured data) was predicted. The optimal relative humidity of the storage environment for maintaining biomass quality for more than 6 months was predicted to be ≤77% and ≤70% for the compressed pellet and ground sample, respectively. Moreover, at a relative humidity ≥77%, giant miscanthus biomass, immediately before compression, had >10% moisture content in 2 days, warranting caution in storage. [ABSTRACT FROM AUTHOR]

Background: Rapid forced expiratory volume in 1 s (FEV1) decliners have been considered a unique subgroup of patients with chronic obstructive pulmonary disease (COPD). Rapid FEV1 decline manifests early and is associated with poor prognosis. This necessitates the pre-emptive identification of risk factors for rapid FEV1 decline. Objectives: We aimed to determine the risk factors and clinical outcomes in patients with COPD. Methods: This longitudinal, observational study was based on the Korea COPD Subgroup Study cohort (NCT02800499) from January 2012 to December 2019 across 54 medical centers in South Korea. Eligible patients were followed up for 3 years with serial spirometric tests. We calculated the annualized percentage change in FEV1 from baseline. Rapid decliners were defined as the quartile of patients with the highest annualized percentage FEV1 decline. Results: Of the 518 patients, 130 were rapid decliners who lost 6.2%/year and 100 mL/year of FEV1. The multivariable logistic regression identified male sex, current smoking, blood eosinophil count <150/µL, and high forced vital capacity as the independent risk factors for rapid FEV1 decline. Among rapid decliners, the lung function deteriorated more rapidly in current smokers and patients with severe dyspnea, while triple combination therapy attenuated lung function decline in comparison with mono-bronchodilator therapy. Rapid decliners had a higher rate of severe exacerbation than nonrapid decliners (0.2/year vs. 0.1/year, p value = 0.032). Conclusions: We identified the independent risk factors for rapid FEV1 decline. This information may assist physicians in the early detection and pertinent management of rapid decline among patients with COPD. [ABSTRACT FROM AUTHOR]

Limited data are available in COVID-19 patients on the prediction of treatment response to systemic corticosteroid therapy based on systemic inflammatory markers. There is a concern whether the response to systemic corticosteroid is different according to white blood cell (WBC) counts in COVID-19 patients. We aimed to assess whether WBC count is related with the clinical outcomes after treatment with systemic corticosteroids in severe COVID-19. We conducted a retrospective cohort study and analysed the patients hospitalised for severe COVID-19 and received systemic corticosteroids between July 2020 and June 2021. The primary endpoint was to compare the composite poor outcome of mechanical ventilation, extracorporeal membrane oxygenation, and mortality among the patients with different WBC counts. Of the 585 COVID-19 patients who required oxygen supplementation and systemic corticosteroids, 145 (24.8%) belonged to the leukopoenia group, 375 (64.1%) belonged to the normal WBC group, and 65 (11.1%) belonged to the leukocytosis group. In Kaplan-Meier curve, the composite poor outcome was significantly reduced in leukopoenia group compared to leukocytosis group (log-rank p-value < 0.001). In the multivariable Cox regression analysis, leukopoenia group was significantly associated with a lower risk of the composite poor outcome compared to normal WBC group (adjusted hazard ratio [aHR] = 0.32, 95% CI 0.14–0.76, p-value = 0.009) and leukocytosis group (aHR = 0.30, 95% CI = 0.12–0.78, p-value = 0.013). There was no significant difference in aHR for composite poor outcome between leukocytosis and normal WBC group. Leukopoenia may be related with a better response to systemic corticosteroid therapy in COVID-19 patients requiring oxygen supplementation. In severe COVID-19 treated with systemic corticosteroids, patients with leukopoenia showed a lower hazard for composite poor outcome compared to patients with normal white blood cell counts or leukocytosis. Leukopoenia may be a potential biomarker for better response to systemic corticosteroid therapy in COVID-19 pneumonia. [ABSTRACT FROM AUTHOR]

Background: Impaired lung function is associated with a higher risk of developing lung cancer. However, lung function is a dynamic variable and must be evaluated longitudinally. This study reports on the relationship between accelerated lung function decline and development of lung cancer.Research Question: Is accelerated lung function decline associated with the development of lung cancer?Study Design and Methods: A longitudinal, observational study was performed by using epidemiologic data from two population-based studies comprising subjects assessed biannually from 2001 to 2019 in South Korea. Eligible subjects were between 40 and 69 years of age and were followed up by using spirometry. Spirometry measurements were made at each follow-up. Patients with a decline in FEV1 > 60 mL per year were defined as rapid FEV1 decliners. The relationship between lung cancer and rapid FEV1 decline was evaluated by using adjusted Cox regression models with covariates, including age, sex, smoking history, FEV1/FVC, and WBC count.Results: Among the 8,549 eligible subjects, 1,287 (15.1%) had rapid FEV1 decline, and 48 (0.6%) had newly developed lung cancer. The risk of lung cancer development was increased in the subjects aged ≥ 45 years and those with ≥ 30 pack-years of smoking, low baseline FEV1/FVC, low forced expiratory flow between 25% and 75% of vital capacity, rapid FEV1 decline, and increased WBC count. Rapid FEV1 decline was an independent risk factor for lung cancer development (adjusted hazard ratio, 2.34; 95% CI, 1.28-4.28; P = .006). Time-dependent net reclassification improvement showed a benefit of FEV1 decline rate in determining subjects at risk of lung cancer when added to conventional practice (categorical, 0.32 [95% CI, 0.00-0.64]; continuous, 0.83 [95% CI, 0.14-1.25]).Interpretation: The FEV1 decline rate may be a potential biomarker for lung cancer development. Further study is needed to identify whether patients with rapid FEV1 decline warrant lung cancer assessment or screening. [ABSTRACT FROM AUTHOR]