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A case study of damage detection in four-bays steel structures using the HHT approach
Hsu, Wen-Ko,Chiou, Dung-Jiang,Chen, Cheng-Wu,Liu, Ming-Yi,Chiang, Wei-Ling,Huang, Pei-Chiung Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.4
This study aims to investigate the relationship between structural damage and sensitivity indices using the Hilbert-Huang transform (HHT) method. Two damage detection indices are proposed: the ratio of bandwidth (RB), and the ratio of effective stiffness (RES). The nonlinear four bays multiple degree of freedom models with various predominant frequencies are constructed using the SAP2000 program. Adjusted PGA earthquake data (Japan 311, Chi-Chi 921) are used as the excitations. Next the damage detection indices obtained using the HHT and the fast Fourier transform (FFT) methods are evaluated based on the acceleration responses of the structures to earthquakes. Simulation results indicate that, the column of the 1 st floor is the first yielding position and the RB value is changed when the RES<90% in all cases. Moreover, the RB value of the 1 st floor changes more sensitive than those from the top floor. In addition, when the structural response is nonlinear (i.e., RES<100%), the RB and the RES curves indicate the incremental change in the HHT spectra. However, the same phenomenon can be found from FFT spectra only when the stiffness reduction is large enough. Therefore, the RB estimated from the smoothed HHT spectra is an effective and sensitive index for detecting structural damage.
Chia-Yu Hsu,Daniel E. Singer,Hooman Kamel,Yi-Ling Wu,Pei-Chun Chen,Jiann-Der Lee,Meng Lee,Bruce Ovbiagele 대한뇌졸중학회 2019 Journal of stroke Vol.21 No.2
Background and Purpose Preceding episodes of paroxysmal atrial fibrillation (AF) among stroke patients can be easily overlooked in routine clinical practice. We aim to determine whether an unrecognized history of paroxysmal AF is associated with an increased risk of recurrent stroke. Methods We retrospectively identified all adult patients hospitalized with a primary diagnosis of ischemic stroke who had no AF diagnosis on their discharge records, using the Taiwan National Health Insurance Research Database between January 2001 and December 2012. Patients were categorized into two groups: unrecognized AF history and no AF. Patients with unrecognized AF history were defined as having documented AF preceding the index ischemic stroke hospitalization, but not recording at the index ischemic stroke. Primary endpoint was recurrent stroke within 1 year after the index stroke. Results Among 203,489 hospitalized ischemic stroke patients without AF diagnosed at discharge, 6,731 patients (3.3%) had an unrecognized history of prior transient AF. Patients with an unrecognized AF history, comparing to those without AF, had higher adjusted risk of all recurrent stroke ([original cohort: hazard ratio (HR), 1.41; 95% confidence interval [CI], 1.30 to 1.53], [matched cohort: HR, 1.51; 95% CI, 1.37 to 1.68]) and recurrent ischemic stroke ([original cohort: HR, 1.42; 95% CI, 1.30 to 1.55], [matched cohort: HR, 1.56; 95% CI, 1.40 to 1.74]) during the 1-year follow-up period. Conclusions Unrecognized history of AF among patients discharged after an index ischemic stroke hospitalization is associated with higher recurrent stroke risk. Careful history review to uncover a paroxysmal AF history is important for ischemic stroke patients.
A case study of damage detection in four-bays steel structures using the HHT approach
Wen-Ko Hsu,Cheng-Wu Chen,Dung-Jiang Chiou,Ming-Yi Liu,Wei-Ling Chiang,Pei-Chiung Huang 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.4
This study aims to investigate the relationship between structural damage and sensitivity indices using the Hilbert-Huang transform (HHT) method. Two damage detection indices are proposed: the ratio of bandwidth (RB), and the ratio of effective stiffness (RES). The nonlinear four bays multiple degree of freedom models with various predominant frequencies are constructed using the SAP2000 program. Adjusted PGA earthquake data (Japan 311, Chi-Chi 921) are used as the excitations. Next, the damage detection indices obtained using the HHT and the fast Fourier transform (FFT) methods are evaluated based on the acceleration responses of the structures to earthquakes. Simulation results indicate that, the column of the 1st floor is the first yielding position and the RB value is changed when the RES<90% in all cases. Moreover, the RB value of the 1st floor changes more sensitive than those from the top floor. In addition, when the structural response is nonlinear (i.e., RES<100%), the RB and the RES curves indicate the incremental change in the HHT spectra. However, the same phenomenon can be found from FFT spectra only when the stiffness reduction is large enough. Therefore, the RB estimated from the smoothed HHT spectra is an effective and sensitive index for detecting structural damage.
Chia-Yu Hsu,Shao-Wen Chiu,Keun-Sik Hong,Jeffrey L. Saver,Yi-Ling Wu,Jiann-Der Lee,Meng Lee,Bruce Ovbiagele 대한뇌졸중학회 2018 Journal of stroke Vol.20 No.1
Background and Purpose Additional folic acid (FA) treatment appears to have a neutral effect on reducing vascular risk in countries that mandate FA fortification of food (e.g., USA and Canada). However, it is uncertain whether FA therapy reduces stroke risk in countries without FA food fortification. The purpose of this study was to comprehensively evaluate the efficacy of FA therapy on stroke prevention in countries without FA food fortification. Methods PubMed, EMBASE, and clinicaltrials.gov from January 1966 to August 2016 were searched to identify relevant studies. Relative risk (RR) with 95% confidence interval (CI) was used as a measure of the association between FA supplementation and risk of stroke, after pooling data across trials in a random-effects model. Results The search identified 13 randomized controlled trials (RCTs) involving treatment with FA that had enrolled 65,812 participants, all of which stroke was reported as an outcome measure. After all 13 RCTs were pooled, FA therapy versus control was associated with a lower risk of any future stroke (RR, 0.85; 95% CI, 0.77 to 0.95). FA alone or combination of FA and minimal cyanocobalamin (≤0.05 mg/day) was associated with a lower risk of future stroke (RR, 0.75; 95% CI, 0.66 to 0.86) whereas combination of FA and cyanocobalamin (≥0.4 mg/day) was not associated with a lower risk of future stroke (RR, 0.95; 95% CI, 0.86 to 1.05). Conclusions FA supplement reduced stroke in countries without mandatory FA food fortification. The benefit was found mostly in patients receiving FA alone or combination of FA and minimal cyanocobalamin.
Chen Cheng-Hsu,Huang Shih-Chien,Yeh En-Ling,Lin Pei-Chih,Tsai Shang-Feng,Huang Yi-Chia 한국영양학회 2022 Nutrition Research and Practice Vol.16 No.4
BACKGROUND/OBJECTIVES Increased levels of uremic toxins and decreased antioxidant capacity have a significant impact on the progression of chronic kidney disease (CKD). However, it remains unclear whether they interact with each other to mediate the damage of kidney function. The purpose of this study was to investigate whether uremic toxins (i.e., homocysteine and indoxyl sulfate [IS]), as well as glutathione-dependent antioxidant enzyme activities are dependently or independently associated with kidney function during different stages of CKD patients. SUBJECTS/METHODS One hundred thirty-two patients diagnosed with CKD at stages 1 to 5 participated in this cross-sectional study. RESULTS Patients who had reached an advanced CKD stage experienced an increase in plasma uremic toxin levels, along with decreased glutathione peroxidase (GSH-Px) activity. Plasma homocysteine, cysteine, and IS concentrations were all positively associated with each other, but negatively correlated to GSH-Px activity levels after adjusting for potential confounders in all CKD patients. Although plasma homocysteine, cysteine, IS, and GSH-Px levels were significantly associated with kidney function, only plasma IS levels still had a significant association with kidney function after these parameters were simultaneously adjusted. In addition, plasma IS could interact with GSH-Px activity to be associated with kidney function. CONCLUSIONS IS plays a more dominant role than homocysteine and GSH-Px activity in relation to kidney function.
GROUND OBSERVATIONS OF SPRITES AND OTHER TLES IN TAIWAN
WANG YUN-CHING,HSU RUE-RON,SU HAN-TZONG,CHEN ALFRED BING-CHIH,LEE YI-JEN,KUO CHENG-LING,TSAY WEAN-SHUN,CHANG CHAN-KAO,WANG SHI-CHUN,LEE LOU-CHUANG,LIU TIE-YUE The Korean Astronomical Society 2005 Journal of The Korean Astronomical Society Vol.38 No.2
Sprites, elves and blue jets are collectively denominated as the upper atmospheric transient luminous events (TLEs). They are recently discovered optical flashes between active thunderstorms and the ionosphere. In this report, a brief introduction to the most important characteristics of TLEs is given. Since 2001, scientists from the National Cheng Kung University have been performing yearly summer campaigns from various locations in Taiwan. The main achievements of their yearly campaign are presented.
Does Spore Count Matter in Fungal Allergy?: The Role of Allergenic Fungal Species
Wan-Rou Lin,Yi-Hsing Chen,Mey-Fann Lee,Ling-Yi Hsu,Chih-Jen Tien,Feng-Ming Shih,Shih-Ching Hsiao,Pi-Han Wang 대한천식알레르기학회 2016 Allergy, Asthma & Immunology Research Vol.8 No.5
Purpose: Fungi have been known to be important aeroallergens for hundreds of years. Most studies have focused on total fungal concentration; however, the concentration of specific allergenic fungi may be more important on an individual basis. Methods: Ten fungal allergic patients and 2 non-fungal allergic patients were enrolled. The patients with a decrease in physician or patient global assessment by more than 50% of their personal best were considered to have an exacerbation of allergic symptoms and to be in the active stage. Those who maintained their physician and patient global assessment scores at their personal best for more than 3 months were considered to be in the inactive stage. The concentrations of dominant fungi in the patients’ houses and outdoors were measured by direct and viable counts at active and inactive stages. Results: The exacerbation of allergic symptoms was not correlated with total fungal spore concentration or the indoor/outdoor ratio (I/O). Specific fungi, such as Cladosporium oxysporum (C. oxyspurum), C. cladosporioides, and Aspergillus niger (A. niger), were found to be significantly higher concentrations in the active stage than in the inactive stage. Presumed allergenic spore concentration threshold levels were 100 CFU/m3 for C. oxysporum, and 10 CFU/m3 for A. niger, Penicillium brevicompactum and Penicillium oxalicum. Conclusions: The major factor causing exacerbation of allergic symptoms in established fungal allergic patients may be the spore concentration of specific allergenic fungi rather than the total fungal concentration. These results may be useful in making recommendations as regards environmental control for fungal allergic patients.
Large-Scale Production of Graphene Nanoribbons from Electrospun Polymers
Liu, Nan,Kim, Kwanpyo,Hsu, Po-Chun,Sokolov, Anatoliy N.,Yap, Fung Ling,Yuan, Hongtao,Xie, Yanwu,Yan, Hao,Cui, Yi,Hwang, Harold Y.,Bao, Zhenan American Chemical Society 2014 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.136 No.49
<P>Graphene nanoribbons (GNRs) are promising building blocks for high-performance electronics due to their high electron mobility and dimensionality-induced bandgap. Despite many past efforts, direct synthesis of GNRs with controlled dimensions and scalability remains challenging. Here we report the scalable synthesis of GNRs using electrospun polymer nanofiber templates. Palladium-incorporated poly(4-vinylphenol) nanofibers were prepared by electrospinning with controlled diameter and orientation. Highly graphitized GNRs as narrow as 10 nm were then synthesized from these templates by chemical vapor deposition. A transport gap can be observed in 30 nm-wide GNRs, enabling them to function as field-effect transistors at room temperature. Our results represent the first success on the scalable synthesis of highly graphitized GNRs from polymer templates. Furthermore, the generality of this method allows various polymers to be explored, which will lead to understanding of growth mechanism and rational control over crystallinity, feature size and bandgap to enable a new pathway for graphene electronics.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2014/jacsat.2014.136.issue-49/ja509871n/production/images/medium/ja-2014-09871n_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja509871n'>ACS Electronic Supporting Info</A></P>