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Clock time-based hourly blood pressure surge around 6 am: Blood pressure dynamics specific to awakening or endogenous circadian rhythm?
No full textCOMMENTAR
An artificial solid interphase with polymers of intrinsic microporosity for highly stable Li metal anodes
No full textPolymers of intrinsic microporosity (PIM-1) have an appropriate pore size to reduce the solvation number of Li ions in electrolytes. This unique pore structure of PIM-1 as a solid interphase can suppress transport of solvent and consequently unwanted chemical reactions at the interface of anodes, thereby extending the cycle life of Li metal anodes.This work was supported by the Korea Center for Artificial Photosynthesis (KCAP) located in Sogang University funded by the Minister of Science, ICT and Future Planning (MSIP) through the National Research Foundation of Korea (No. 2009-0093883). This work was also supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2017R1A2B2012847)
Natural zeolite and its application in concrete composite production
No full textConcrete is a composite material that is widely used in the construction industry due to its excellent mechanical and physical properties. Despite these benefits, concrete possesses several disadvantages including negative environmental impacts and mechanical durability (e.g., shrinkage, frost attack, and corrosion). To date, upgrading of concretes properties to overcome such drawbacks has been one of the most challenging, but attractive, research topics for many researchers in this research field. As one of the effective means to meet such demand, the use of natural zeolites in the production of concrete has been made preferably to acquire the excellent performance along with improvement in terms of structure, durability, and mechanical properties. This review was designed to provide a comprehensive insight into the construction-related applications of natural zeolite. To this end, we discussed the structural and fundamental properties of natural zeolites and their applications to concrete production as natural pozzolans, internal curing agents, and lightweight aggregates. Also, through critical analysis of various researches made previously, we aim to offer a better understanding on the effect of zeolites' addition upon the performance of concrete in terms of workability, strength, durability, and permeability. Additionally, we describe the present challenges and future perspectives in the use of natural zeolites for concrete production.This study was supported by a grant from the National Research Foundation of Korea, funded by the Ministry of Science, ICT and Future Planning (Grant No. 2016R1E1A1A01940995), and in part by the R&D Center for Green Patrol Technologies through the R&D for Global Top Environmental Technologies program, funded by the Ministry of Environment of the Republic of Korea (Grant No: 2018001850001)
Bronchopulmonary Dysplasia Is Associated with Altered Brain Volumes and White Matter Microstructure in Preterm Infants
No full textBackground: Bronchopulmonary dysplasia (BPD), an inflammatory disease involving disrupted lung development, is associated with neurodevelopmental outcome in preterm infants. Objective: This study examined the brain volume and white matter (WM) microstructure in preterm infants at term-equivalent age and explored the effects of BPD on brain development. Method: We studied 56 preterm infants (33 with BPD and 23 without BPD) with no evidence of focal abnormalities on conventional magnetic resonance imaging (MRI) at term-equivalent age. Regional brain volumes and diffusion tensor images were examined using advanced segmentation techniques to acquire quantitative volume measurements, and the JHU neonatal template was used for the atlas-based analysis. We compared these infants with 22 healthy term infants of a similar postmenstrual age. Results: The preterm infants with BPD had smaller cerebral WM (p = 0.005) volumes than the preterm infants without BPD, independent of sex, gestational age, age at MRI scan, and total intracranial volume. Independent of sex, gestational age, and age at MRI scan, the preterm infants with BPD exhibited marked reductions in fractional anisotropy in the corpus callosum (p = 0.006), corticospinal tract (p = 0.003), and superior cerebellar peduncle (p = 0.002) compared with the infants with no BPD, with a significance level of p <= 0.008 as a Bonferroni correction for multiple comparisons. Conclusion: Our study highlights the potential impairing influence of BPD on WM and cerebellar development in preterm infants compared with those without BPD at term-equivalent age, suggesting its clinical significance for neurodevelopment in BPD infants. (C) 2019 S. Karger AG, BaselThis work was supported by the National Research Foundation of Korea Grant funded by the Korean Government MSIT (NRF-2017-R1C1B5015046) and the research fund of Hanyang University (HY-2017)
Silver-Adapted Diffusive Memristor Based on Organic Nitrogen-Doped Graphene Oxide Quantum Dots (N-GOQDs) for Artificial Biosynapse Applications
No full textCarbon-based electronic devices are suitable candidates for bioinspired electronics due to their low cost, eco-friendliness, mechanical flexibility, and compatibility with complementary metal-oxide-semiconductor technology. New types of materials such as graphene quantum dots (GQDs) have attracted attention in the search for new applications beyond solar cells and energy harvesting due to their superior properties such as elevated photoluminescence, high chemical inertness, and excellent biocompatibility. In this paper, a biocompatible/organic electronic synapse based on nitrogen-doped graphene oxide quantum dots (N-GOQDs) is reported, which exhibits threshold resistive switching via silver cation (Ag+) migration dynamics. In analogy to the calcium (Ca2+) ion dynamics of biological synapses, important biological synapse functions such as short-term potentiation (STP), paired-pulse facilitation, and transition from STP to long-term plasticity behaviors are replicated. Long-term depression behavior is also evaluated and specific spike-timing dependent plasticity is assessed. In addition, elaborated switching mechanism of biosimilar Ag+ migration dynamics provides the potential for using N-GOQD-based artificial synapse in future biocompatible neuromorphic systems.A.S.S. and M.A. contributed equally to this work. This research was supported by the Nano Material Technology Development Programs through the National Research Foundation of Korea (NRF) funded by the Ministry of science, ICT & Future Planning (NRF-2016M3A7B4910426) as well as (NRF-2015M3A7B7045490). This work was also supported by the Global Frontier R&D Program on Center for Multiscale Energy System Research (No. 2012M3A6A7054856) and Research Program (2018R1A2B2006708) funded by the National Research Foundation under the Ministry of Science, ICT & Future Planning, Republic of Korea
An Analysis on the Policy Network Structure of TourismStartup Support Policy of Local Government
No full text본 연구는 지방정부 관광스타트업지원정책에 있어서 정책행위자들 간의 관계구조를 분석하는 데 목적을 두었다. 이론적 고찰에서는 관광스타트업지원정책, 정책네트워크에 대한 개념고찰과 선행연구에 대한 검토가 이루어졌다. 분석모형은 정책네트워크를 구성하는 정책행위자와 관광스타트업지원정책의 정책영역 그리고 분석요인으로 구조화하였다. 자료수집에 있어서는 서울시의 관광스타트업지원정책을 사례로 초점집단표집법을 통하여 정책행위자를 선정하고 조사를 실시하였으며, 분석방법으로는 사회연결망분석법을 사용하였다. 분석결과 서울시 관광스타트업지원정책에 있어서 정책네트워크의 응집력은 비교적 양호한 수준으로 나타났으며 전반적인 영역과 세부정책영역에서 한국관광공사와 서울특별시가 각각 중심적 영향력을 가진 것으로 분석되었다. 또한 전반적 영역에서 한국관광스타트업협회가, 세부정책영역에서는 문화체육관광부, 한국관광협회중앙회가 전략적 위치에 있는 것으로 분석되었다. 결론적으로 지방정부 관광스타트업지원정책의 정책네트워크는 도입단계의 정책네트워크적 특성을 보이는 것으로 확인되었다. 연구의 시사점으로는 지방정부의 효과적인 관광스타트업지원정책 추진을 위한 방안이 제시되었다. This study aimed at analyzing the policy network structure of tourism startup support policy of local government by using social network analysis method. The literature review covered the concepts of tourism startup support policy, policy network, and the related precedent studies. For the research design, an analytical model was proposed. The model was composed of policy actors, policy areas, and analytical factors. For the research case Seoul Metropolitan Government was selected. And the data was collected by focus group sampling method. The findings showed that in the analysis of density, the cohesion of tourism startup support policy network was in relatively good level. And in the analysis of centrality, Korea Tourism Organization and Seoul Metropolitan Government had central influence in overall policy area and sub-policy area respectively. And in the analysis of structural hole, Korea Tourism Startup Association occupied a strategic position in overall policy area, meanwhile, Ministry of Culture, Tourism and Sports and Korea Tourism Association occupied a strategic position in sub-policy area. Based on the findings, theoretical implications were discussed and practical suggestions were made for effective implementation of tourism startup support policy of local government
Clinical outcomes of patients with active rheumatoid arthritis with normal acute phase reactant values
No full textAim Despite high clinical disease activity, some patients with active rheumatoid arthritis (RA) have normal acute phase reactant (APR) values. This study aimed to determine the clinical outcomes of active RA patients with normal APR values. Method Of 5376 patients with RA enrolled in the Korean observational study network for arthritis (KORONA) registry, 400 patients with disease duration of ˂2 years who had Clinical Disease Activity Index (CDAI) score of ˃2.8 at baseline, biologic-naive, and erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) drawn at both baseline and 2-year follow-up visits were identified. Patients were grouped according to baseline APR levels: normal APRs, one APR elevated, and both APRs elevated. Results Baseline tender and swollen joint counts, mean CDAI and Health Assessment Questionnaire-Disability Index (HAQ-DI) scores were significantly lower in the normal APRs group compared with APR-elevated groups (P ˂ 0.0001). At 2-year follow-up, mean CDAI scores, HAQ-DI, and percentage of the patient achieving remission were not significantly different between the normal APRs group compared with the APR-elevated groups regardless of the baseline disease activity. However, in patients with baseline CDAI moderate to high disease activity, the normal APRs group less frequently required initiation of the biologic disease-modifying anti-rheumatic drugs compared with the APR-elevated groups (P = 0.044). Conclusion Active RA patients with normal APR values have milder disease presentation, but similar clinical outcomes to those with elevated APRs.This study was supported by a grant of the Korea Health technology R&D project through the Korea Health Industry Development Institute, funded by the Ministry of Health and Welfare, Republic of Korea (grant number: HI10C2020)
Bronchopulmonary Dysplasia Is Associated with Altered Brain Volumes and White Matter Microstructure in Preterm Infants.
No full textBackground: Bronchopulmonary dysplasia (BPD), an inflammatory disease involving disrupted lung development, is associated with neurodevelopmental outcome in preterm infants. Objective: This study examined the brain volume and white matter (WM) microstructure in preterm infants at term-equivalent age and explored the effects of BPD on brain development. Method: We studied 56 preterm infants (33 with BPD and 23 without BPD) with no evidence of focal abnormalities on conventional magnetic resonance imaging (MRI) at term-equivalent age. Regional brain volumes and diffusion tensor images were examined using advanced segmentation techniques to acquire quantitative volume measurements, and the JHU neonatal template was used for the atlas-based analysis. We compared these infants with 22 healthy term infants of a similar postmenstrual age. Results: The preterm infants with BPD had smaller cerebral WM (p = 0.005) volumes than the preterm infants without BPD, independent of sex, gestational age, age at MRI scan, and total intracranial volume. Independent of sex, gestational age, and age at MRI scan, the preterm infants with BPD exhibited marked reductions in fractional anisotropy in the corpus callosum (p = 0.006), corticospinal tract (p = 0.003), and superior cerebellar peduncle (p = 0.002) compared with the infants with no BPD, with a significance level of p <= 0.008 as a Bonferroni correction for multiple comparisons. Conclusion: Our study highlights the potential impairing influence of BPD on WM and cerebellar development in preterm infants compared with those without BPD at term-equivalent age, suggesting its clinical significance for neurodevelopment in BPD infants. (C) 2019 S. Karger AG, BaselThis work was supported by the National Research Foundation of Korea Grant funded by the Korean Government MSIT (NRF-2017-R1C1B5015046) and the research fund of Hanyang University (HY-2017)
Performance evaluation of a hybrid dust collector for removing particles during subway train operation
No full textA hybrid dust collector attached to a subway train bottom was developed for the effective removal of subway particulate matter (PM), by considering the fluctuating speed of a subway train between stations. It combines an electrostatic precipitator, which has good collection efficiency when the flow velocity is low, and an inertial dust separator, which has good collection efficiency when the flow velocity is high. The electrostatic precipitator and inertial dust separator guarantee a high collection efficiency regardless of the subway train operating speed by compensating for the other's shortcomings. Wind tunnel test and numerical simulation were conducted to verify the performance of the hybrid dust collector. The experiment and simulation results were compared to verify the prediction accuracy of the simulation method. The collection efficiencies of the electrostatic precipitator and inertial dust separator were then simulated for various operating speeds of the subway train to predict the overall collection efficiency of the hybrid dust collector. As a result, when airflow velocity at the hybrid dust collector inlet varied from 2 to 8m/s, subway PM10 or PM2.5 collection rate of a single hybrid dust collector was predicted to be in the range 88 approximate to 123g/s or 30 approximate to 35g/s, respectively. The use of multiple such hybrid dust collectors attached to the subway train bottom is expected to be effective in reducing fine dust concentration in subway tunnels.Copyright (c) 2019 American Association for Aerosol ResearchThis work was supported by research grants for the Railway Technology Research Project from the Ministry of Land, Infrastructure and Transport, Republic of Korea (18RTRP-B082486-05)
Evaluation of changes in choroidal thickness and the choroidal vascularity index after hemodialysis in patients with end-stage renal disease by using swept-source optical coherence tomography
No full textTo evaluate the effect of hemodialysis on choroidal thickness and the choroidal vascularity index (CVI) in patients with end-stage renal disease (ESRD) by using swept-source optical coherence tomography.
Thirty-two eyes of 32 patients with ESRD undergoing hemodialysis were recruited prospectively. Detailed ophthalmologic examinations and swept-source optical coherence tomography were performed immediately before and after hemodialysis. Choroidal thickness maps were generated automatically by using built-in software. The CVI was calculated using binarized choroidal optical coherence tomography images. Systemic parameters such as body weight and blood pressure were also measured. The changes in systemic and ocular parameters during hemodialysis were evaluated. Subjects were divided into 2 groups (diabetes mellitus [DM] vs non-diabetes mellitus) for subgroup analysis.
Total choroidal thickness showed a significant overall decrease after hemodialysis (-10.9 +/- 14.0, P<. 001). In the subgroup analysis, total choroidal thickness significantly decreased in both patients with DM (-11.3 +/- 13.6, P=. 004) and those without (-10.6 +/- 14.9, P=. 020), but the reduction of choroidal thickness was observed in more subfields in patients with DM than in those without. The CVI did not significantly change after hemodialysis (P=. 717). No significant systemic and ocular factors affected the changes in total choroidal thicknesses.
Choroidal thickness significantly decreased after hemodialysis in most subfields regardless of the presence of DM. Perihemodialysis choroidal changes could be considered in the management of patients with ESRD. Swept-source optical coherence tomography can provide ample and reliable quantitative data for monitoring ocular hemodynamic changes.This research was supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (NRF-2017R1D1A1B03030905 and NRF-2017R1D1A1B03031934)