Spintronics relies on magnetization switching through current-induced spin torques. However, because spin transfer torque for ferromagnets is a surface torque, a large switching current is required ...for a thick, thermally stable ferromagnetic cell, and this remains a fundamental obstacle for high-density non-volatile applications with ferromagnets. Here, we report a long spin coherence length and associated bulk-like torque characteristics in an antiferromagnetically coupled ferrimagnetic multilayer. We find that a transverse spin current can pass through >10-nm-thick ferrimagnetic Co/Tb multilayers, whereas it is entirely absorbed by a 1-nm-thick ferromagnetic Co/Ni multilayer. We also find that the switching efficiency of Co/Tb multilayers partially reflects a bulk-like torque characteristic, as it increases with ferrimagnet thickness up to 8 nm and then decreases, in clear contrast to the 1/thickness dependence of ferromagnetic Co/Ni multilayers. Our results on antiferromagnetically coupled systems will invigorate research towards the development of energy-efficient spintronics.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Background and Objective
Preterm birth or fetal growth has been associated with reduced lung function and asthma during childhood in the general population. We aimed to elucidate whether prematurity ...or fetal growth has a significant influence on lung function or symptoms in children with stable asthma.
Methods
We included children with stable asthma who participated in the Korean childhood Asthma Study cohort. Asthma symptoms were determined by asthma control test (ACT). Percent predicted values of pre‐ and post‐bronchodilator (BD) lung function including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and forced expiratory flow at 25%–75% of FVC (FEF25%–75%) were measured. Lung function and symptoms were compared according to the history of preterm birth and birth weight (BW) for gestational age (GA).
Results
The study population consisted of 566 children (age range: 5–18 years). There were no significant differences in lung function and ACT between preterm and term subjects. We observed no significant difference in ACT but significant differences were observed in pre‐ and post‐BD FEV1, pre‐ and post‐BD FVC, and post‐BD FEF25%–75% according to BW for GA in total subjects. Two‐way ANOVA revealed that BW for GA rather than prematurity was a significant determining factor for pre‐ and post‐BD lung function. After regression analysis, BW for GA was still a significant determining factor of pre‐ and post‐BD FEV1 and pre‐ and post‐BD FEF25%–75%.
Conclusion
Fetal growth rather than prematurity appears to have a significant effect on lung function in children with stable asthma.
Preterm birth or fetal growth has been associated with reduced lung function and asthma. We found that lung function decreased according to fetal growth, but did not differ according to history of prematurity in children with stable asthma. Fetal growth rather than prematurity has a lasting effect on lung function.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The occurrence of numerous cases of interstitial lung disease in children (chILD) every spring in Korea starting in 2006 raised suspicion about a causal relationship with the use of humidifier ...disinfectants (HDs). The aim of this study was to evaluate the association between HD use and the risk of chILD.
This retrospective, 1∶3 matched case-control study consisted of 16 cases of chILD that had developed between 2010 and 2011. The three groups of parallel controls (patients with acute lobar pneumonia, asthma, and healthy children) were matched by age, gender, and index date. Indoor/outdoor environmental risk factors, including HD use, were investigated by asking the guardians to complete a questionnaire.
The median age of the affected children (43.8% male) was 26 months (18.25-36.25). The chILD group did not differ significantly from the control groups with respect to socio-demographic and clinical variables. Indoor and outdoor environmental factors were not associated with a risk of chILD. However, the previous use of HDs (OR; 2.73. 95% CI; 1.41-5.90, P = 0.00) were independently associated with an increased risk.
This study showed that HDs, which are widely used in South Korea in the winter season, independently increased the risk of chILD in spring. Therefore, continuous monitoring and, if needed, changes in policy are essential to prevent and control pediatric diseases caused by toxic chemicals.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Leukotriene receptor antagonists (LTRAs) are widely used for asthma and allergic rhinitis (AR), but concerns about the risk of neuropsychiatric events (NPEs) have been raised since the first Drug ...Safety Communication by the US Food and Drug Administration in 2008. This study evaluates the association between LTRA and NPEs in children, adolescents, and young adults with asthma or AR.A self-controlled case series study was conducted using the Korean National Health Insurance Service claims database from two three-year observation periods (observation period 1 Obs1: 2005 to 2007, observation period 2 Obs2: 2016 to 2018). Asthma or AR patients aged 3-30 years who were prescribed LTRAs and diagnosed with NPEs were included. The incidence rate ratios (IRRs) for exposed period and risk periods (1-3, 4-7, 8-14, 15-30, 31-90, >90 days from initiation of LTRA) compared to unexposed periods were calculated using conditional Poisson regression. Subgroup analysis according to age group, type of NPEs and indication of LTRA was performed.Among 17 001 included patients, the risk of NPEs increased in Obs2 (IRR, 1.11; 95% confidence interval CI, 1.00-1.22), but did not increase in Obs1. Risk was increased during risk periods 4-7 days (2.36, 1.99-2.76) and 8-14 days (1.78; 1.46-2.15) after initiation of LTRA, particularly in adolescents (1.28, 1.05-1.55) and young adults (1.14, 1.02-1.28), while risk was decreased in children (3-11 years). Risk was not increased for any single type of NPE. AR patients were at increased risk (1.19, 1.01-1.39), but not those with asthma.Overall, risk of NPEs with LTRA use differed between risk periods and subgroups. Physicians should prescribe LTRAs according to indications and inform patients about possible NPEs.
We report that polymerization makes a robust, practically applicable multifunctional optical device with a continuous wavelength tunable over 500 nm spectral range using UV-polymerizable cholesteric ...liquid crystals (CLCs). It can be used as a circular polarizer generating an extremely high degree of circularly polarized light with |g| = 1.85~2.00. It can also be used for optical notch filters, bandwidth-variable (from ~28 nm to ~93 nm) bandpass filters, mirrors, and intensity-variable beam splitters. Furthermore, this CLC device shows excellent stability owing to the polymerization of CLC cells. Its performance remains constant for a long time (~2 years) after a high-temperature exposure (170 °C for 1 h) and an extremely high laser beam intensity exposure (~143 W/cm2 of CW 532 nm diode laser and ~2.98 MW/cm2 of Nd: YAG pulse laser operation for two hours, respectively). The optical properties of polymerized CLC were theoretically analyzed by Berreman’s 4 × 4 matrix method. The characteristics of this device were significantly improved by introducing an anti-reflection layer on the device. This wavelength-tunable and multifunctional device could dramatically increase optical research efficiency in various spectroscopic works. It could be applied to many instruments using visible and near-infrared wavelengths.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Background
Asthma exacerbation (AE) leads to social and economic costs and long‐term adverse outcomes. We aimed to predict exacerbation‐prone asthma (EPA) in children.
Methods
The Korean childhood ...Asthma Study (KAS) is a prospective nationwide pediatric asthma cohort of children aged 5–15 years followed every 6 months. Patients with AE during the 6 months prior to all three visits, with AE prior to one or two visits, and without AE prior to any visit were defined as having EPA, exacerbation‐intermittent asthma (EIA), and exacerbation‐resistant asthma (ERA), respectively. Risk factors and prediction models of EPA were explored.
Results
Of the 497 patients who completed three visits, 42%, 18%, and 15% had exacerbations prior to visits 1, 2, and 3 and 5%, 47%, and 48% had EPA, EIA, and ERA, respectively. Univariate and multivariable logistic regression revealed forced expiratory volume in 1 s (FEV1) z‐score, forced vital capacity (FVC) z‐score, white blood cell (WBC) count, and asthma control test (ACT) score as relevant EPA risk factors. The EPA prediction model comprised FVC z‐score, WBC count, ACT score, sex, and parental education level (area under the receiver operating characteristic curve AUROC 0.841 95% confidence interval (CI): 0.728–0.954).
Conclusion
With appropriate management, AE decreases over time, but persistent AEs may occur. Apart from asthma control level, baseline lung function and WBC count predicted EPA.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Community-acquired pneumonia (CAP) is one of the leading worldwide causes of childhood morbidity and mortality. Its disease burden varies by age and etiology and is time dependent. We aimed to ...investigate the annual and seasonal patterns in etiologies of pediatric CAP requiring hospitalization.
We conducted a retrospective study in 30,994 children (aged 0-18 years) with CAP between 2010 and 2015 at 23 nationwide hospitals in South Korea. Mycoplasma pneumoniae (MP) pneumonia was clinically classified as macrolide-sensitive MP, macrolide-less effective MP (MLEP), and macrolide-refractory MP (MRMP) based on fever duration after initiation of macrolide treatment, regardless of the results of in vitro macrolide sensitivity tests.
MP and respiratory syncytial virus (RSV) were the two most commonly identified pathogens of CAP. With the two epidemics of MP pneumonia (2011 and 2015), the rates of clinical MLEP and MRMP pneumonia showed increasing trends of 36.4% of the total MP pneumonia. In children < 2 years of age, RSV (34.0%) was the most common cause of CAP, followed by MP (9.4%); however, MP was the most common cause of CAP in children aged 2-18 years of age (45.3%). Systemic corticosteroid was most commonly administered for MP pneumonia. The rate of hospitalization in intensive care units was the highest for RSV pneumonia, and ventilator care was most commonly needed in cases of adenovirus pneumonia.
The present study provides fundamental data to establish public health policies to decrease the disease burden due to CAP and improve pediatric health.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•A punching shear strength model was proposed for UHPFRC-RC composite flat plates.•UHPFRC overlay increases the load-carrying capacity, but it is limited at a certain point.•The punching shear ...strength can be defined as a function of the thickness and strength of UHPFRC overlay.
Reinforced concrete (RC) flat plates are vulnerable to punching shear failure due to small effective area for shear resistance. To strengthen the behavior of existing flat plates, use of ultra high performance fiber reinforced concrete (UHPFRC) as a laminate has been pursued. This study focuses on punching shear behavior of RC flat plates retrofitted with UHPFRC overlay (i.e., UHPFRC-RC composite flat plates). To model the axisymmetric UHPFRC-RC composite flat plate, use of the unified strength theory-based punching shear strength model was proposed. Predictions using the proposed model, when compared to existing test results of UHPFRC-RC composite flat plates under concentric load and nonlinear analysis results using ABAQUS, agreed well with the results. Additionally, from the parametric analysis results using the proposed model and nonlinear analysis, the effects of UHPFRC overlay thickness and tensile strength on the punching shear strength were identified.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Although anaphylaxis is recognized as an important, life-threatening condition, data are limited regarding its triggers in different age groups. We aimed to identify anaphylaxis triggers by age in ...Korean children.
We performed a retrospective review of medical records for children diagnosed with anaphylaxis between 2009 and 2013 in 23 secondary or tertiary hospitals in South Korea.
A total of 991 cases (mean age=5.89±5.24) were reported, with 63.9% involving patients younger than 6 years of age and 66% involving male children. Food was the most common anaphylaxis trigger (74.7%), followed by drugs and radiocontrast media (10.7%), idiopathic factors (9.2%), and exercise (3.6%). The most common food allergen was milk (28.4%), followed by egg white (13.6%), walnut (8.0%), wheat (7.2%), buckwheat (6.5%), and peanut (6.2%). Milk and seafood were the most common anaphylaxis triggers in young and older children, respectively. Drug-triggered anaphylaxis was observed more frequently with increasing age, with antibiotics (34.9%) and nonsteroidal anti-inflammatory drugs (17.9%) being the most common causes.
The most common anaphylaxis trigger in Korean children was food. Data on these triggers show that their relative frequency may vary by age.
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