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Substrate-free Biosensing using Brownian Rotation of Bio-conjugated Magnetic Nanoparticles
Seok-Hwan Chung,Axel Hoffmann,Liaohai Chen,Shouheng Sun,Konstantin Guslienko,Marcos Grimsditch,Samuel D. Bader 한국자기학회 2006 Journal of Magnetics Vol.11 No.4
The recent development of bio-conjugated magnetic nanoparticles offers many opportunities for applications in the field of biomedicine. In particular, the use of magnetic nanoparticles for biosensing has generated widespread research efforts following the progress of various magnetic field sensors. Here we demonstrate substrate-free biosensing approaches based on the Brownian rotation of ferromagnetic nanoparticles suspended in liquids. The signal transduction is through the measurement of the magnetic ac susceptibility as a function of frequency, whose peak position changes due to the modification of the hydrodynamic radius of bio-conjugated magnetic nanoparticles upon binding to target bio-molecules. The advantage of this approach includes its relative simplicity and integrity compared to methods that use substrate-based stray-field detectors.
안승천(Sung-Chen Ahan),이상문(Sang-Mun Lee),김용환(Yong-Hwan Kim),정원섭(Won-Sub Chung) 한국표면공학회 2006 한국표면공학회지 Vol.39 No.5
The current efficiency of copper anode containing impurities in copper sulfate solution for electrorefining was studied at various current type such as direct current, variable current and periodic reverse current. The passivity behavior was investigated by galvanostatic technique. The results obtained were that current efficiency of variable current was higher than those of direct current and periodic reverse current. The increased current efficiency could be explained by the formation of slime structure with lower average resistance due to variable current. The frequency of various factors in variable current condition has a greatest effect on current efficiency. It appeared that frequency increased current efficiency when increased from 1 to 4, but further increases did not have an effect.
As, Sb, Bi, Pb가 조동의 부동태에 미치는 영향
안승천(Sung-Chen Ahan),이상문(Sang-Mun Lee),김용환(Yong-Hwan Kim),정원섭(Won-Sub Chung),정우창(Uoo-Chang Chung) 한국표면공학회 2006 한국표면공학회지 Vol.39 No.5
The passivity behavior of copper anode containing impurities in copper sulfate solution for electrorefining process was studied at several different levels of impurities such as As, Sb, Bi and Pb. The passivity behavior was investigated by electrochemical techniques (galvanostatic, potentiodynamic and cyclic voltammetry tests) and surface analysis (optical microscopy, electron probe microanalysis, scanning electron microscopy). The results were that arsenic, antimony inhibited passivation and bismuth accelerated it and lead containing anode showed different passivity behavior from above anodes. The improved passivity characteristics could be explained by decrease in oxygen content in passivity film which resulted from a reaction among the impurities, oxygen and copper in the anode. The SEM image revealed that arsenic or antimony containing anode exhibited a porous passivity film and bismuth containing anode showed the compact passivity film and lead containing anode had loose passivity film on anode.
John, Johnson V.,Chung, Chung-Wook,Johnson, Renjith P.,Jeong, Young-Il,Chung, Kyu-Don,Kang, Dae Hwan,Suh, Hongsuk,Chen, Hongyu,Kim, Il American Chemical Society 2016 Biomacromolecules Vol.17 No.1
<P>Smart delivery system of photosensitizer chlorin e6 (Ce6) has been developed for targeted photodynamic therapy (PDT). Simple self-assemblies of the mixtures comprising soybean lecithin derived phosphatidylcholine (PC), phosphatidylethanolamine-poly(L-histidine)(40) (PE-p-(His)(40)), and folic acid (FA) conjugated phosphatidylethanolamine-poly(N-isopropylacrylamide)(40) (PE-p(NIPAM)(40)-FA) in different ratios yield smart nanospheres characterized by (i) stable and uniform particle size (similar to 100 nm), (ii) positive surface charge, (iii) high hydrophobic drug (Ce6) loading efficiency up to 45%, (iv) covalently linked targeting moiety, (v) low cytotoxicity, and (vi) smartness showing p(His) block oriented pH and p(NIPAM) oriented temperature responsiveness. The Ce6-encapsulated vesicular nanospheres (Ce6@VNS) were used to confirm the efficiency of cellular uptake, intracellular distribution, and phototoxicity against KB tumor cells compared to free Ce6 at different temperature and pH conditions. The Ce6@VNS system showed significant photodynamic therapeutic efficiency on KB cells than free Ce6. A receptor-mediated inhibition study proved the site-specific delivery of Ce6 in targeted tumor cells.</P>
Crystal field effects on the photoluminescence properties of Y1−x La x VO4:Eu3+ phosphors
Shim, Kyoo Soung,Yang, Hyun Kyoung,Chung, Jong Won,Chen, Yeqing,Moon, Byung Kee,Choi, Byung Chun,Jeong, Jung Hyun,Kim, Jung Hwan,Kim, Kwang Ho Springer-Verlag 2011 APPLIED PHYSICS A MATERIALS SCIENCE AND PROCESSING Vol.104 No.1
Kim, Hyo Jeong,Joe, Yeonsoo,Chen, Yingqing,Park, Gyu Hwan,Kim, Uh‐,Hyun,Chung, Hun Taeg John Wiley and Sons Inc. 2019 Aging cell Vol.18 No.1
<P><B>Abstract</B></P><P>Amyloid‐β (Aβ) peptides, the major constituent of plaques, are generated by sequential proteolytic cleavage of the amyloid precursor protein (APP) via β‐secretase (BACE1) and the γ‐secretase complex. It has been proposed that the abnormal secretion and accumulation of Aβ are the initial causative events in the development of Alzheimer's disease (AD). Drugs modulating this pathway could be used for AD treatment. Previous studies indicated that carbon monoxide (CO), a product of heme oxygenase (HO)‐1, protects against Aβ‐induced toxicity and promotes neuroprotection. However, the mechanism underlying the mitigative effect of CO on Aβ levels and BACE1 expression is unclear. Here, we show that CO modulates cleavage of APP and Aβ production by decreasing BACE1 expression in vivo and in vitro. CO reduces Aβ levels and improves memory deficits in AD transgenic mice. The regulation of BACE1 expression by CO is dependent on nuclear factor‐kappa B (NF‐κB). Consistent with the negative role of SIRT1 in the NF‐κB activity, CO fails to evoke significant decrease in BACE1 expression in the presence of the SIRT1 inhibitor. Furthermore, CO attenuates elevation of BACE1 level in brains of 3xTg‐AD mouse model as well as mice fed high‐fat, high‐cholesterol diets. CO reduces the NF‐κB‐mediated transcription of BACE1 induced by the cholesterol oxidation product 27‐hydroxycholesterol or hydrogen peroxide. These data suggest that CO reduces the NF‐κB‐mediated BACE1 transcription and consequently decreases Aβ production. Our study provides novel mechanisms by which CO reduces BACE1 expression and Aβ production and may be an effective agent for AD treatment.</P>
The development of Taiwan Fracture Liaison Service network
Lo-Yu Chang,Keh-Sung Tsai,Jen-Kuei Peng,Chung-Hwan Chen,Gau-Tyan Lin,Chin-Hsueh Lin,Shih-Te Tu,I-Chieh Mao,Yih-Lan Gau,Hsusan-Chih Liu,Chi-Chien Niu,Min-Hong Hsieh,Jui-Teng Chien,Wei-Chieh Hung,Rong-S 대한골다공증학회 2018 Osteoporosis and Sarcopenia Vol.4 No.2
Osteoporosis and its associated fragility fractures are becoming a severe burden in the healthcare system globally. In the Asian-Pacific (AP) region, the rapidly increasing in aging population is the main reason accounting for the burden. Moreover, the paucity of quality care for osteoporosis continues to be an ongoing challenge. The Fracture Liaison Service (FLS) is a program promoted by International Osteoporosis Foundation (IOF) with a goal to improve quality of postfracture care and prevention of secondary fractures. In this review article, we would like to introduce the Taiwan FLS network. The first 2 programs were initiated in 2014 at the National Taiwan University Hospital and its affiliated Bei-Hu branch. Since then, the Taiwan FLS program has continued to grow exponentially. Through FLS workshops promoted by the Taiwanese Osteoporosis Association (TOA), program mentors have been able to share their valuable knowledge and clinical experience in order to promote establishments of additional programs. With 22 FLS sites including 11 successfully accredited on the best practice map, Taiwan remains as one of the highest FLS coverage countries in the AP region, and was also granted the IOF Best Secondary Fracture Prevention Promotion award in 2017. Despite challenges faced by the TOA, we strive to promote more FLS sites in Taiwan with a main goal of ameliorating further health burden in managing osteoporotic patients.
Hsu Chiao-Lin,Wu Pin-Chieh,Yin Chun-Hao,Chen Chung-Hwan,Lee King-Teh,Lin Chih-Lung,Shi Hon-Yi 대한영상의학회 2023 Korean Journal of Radiology Vol.24 No.12
Objective: This study aimed to evaluate the clinical outcomes and cost-effectiveness of dual-energy X-ray absorptiometry (DXA) for osteoporosis screening. Materials and Methods: Eligible patients who had and had not undergone DXA screening were identified from among those aged 50 years or older at Kaohsiung Veterans General Hospital, Taiwan. Age, sex, screening year (index year), and Charlson comorbidity index of the DXA and non-DXA groups were matched using inverse probability of treatment weighting (IPTW) for propensity score analysis. For cost-effectiveness analysis, a societal perspective, 1-year cycle length, 20-year time horizon, and discount rate of 2% per year for both effectiveness and costs were adopted in the incremental cost-effectiveness (ICER) model. Results: The outcome analysis included 10337 patients (female:male, 63.8%:36.2%) who were screened for osteoporosis in southern Taiwan between January 1, 2012, and December 31, 2021. The DXA group had significantly better outcomes than the non-DXA group in terms of fragility fractures (7.6% vs. 12.5%, P < 0.001) and mortality (0.6% vs. 4.3%, P < 0.001). The DXA screening strategy gained an ICER of US$ -2794 per quality-adjusted life year (QALY) relative to the non-DXA at the willingness-to-pay threshold of US$ 33004 (Taiwan’s per capita gross domestic product). The ICER after stratifying by ages of 50–59, 60–69, 70–79, and ≥ 80 years were US$ -17815, US$ -26862, US$ -28981, and US$ -34816 per QALY, respectively. Conclusion: Using DXA to screen adults aged 50 years or older for osteoporosis resulted in a reduced incidence of fragility fractures, lower mortality rate, and reduced total costs. Screening for osteoporosis is a cost-saving strategy and its effectiveness increases with age. However, caution is needed when generalizing these cost-effectiveness results to all older populations because the study population consisted mainly of women.