Distribution of Alexandrium tamarense in Drake Passage and the Threat of Harmful Algal Blooms in the Antarctic Ocean

King-Chung Ho,강성호,Ironside H. Y. Lam,I. John Hodgkiss 한국해양과학기술원 2003 Ocean and Polar Research Vol.25 No.3s

Distribution of Alexandrium tamarense in Drake Passage and the Threat of Harmful Algal Blooms in the Antarctic Ocean

Ho, King-Chung,Kang, Sung-Ho,,Lam Ironside H.Y.,Ho, dgkiss I.John Korea Institute of Ocean ScienceTechnology 2003 Ocean and Polar Research Vol.25 No.4

While phytoplankton diversity and productivity in the Southern Ocean has been widely studied in recent years, most attention has been given to elucidating environmental factors that affect the dynamics of micro-plankton (mainly diatoms) and nano-plankton (mainly Phaeocystis antarctica). Only limited effects have been given to studying the occurrence and the potential risks associated with the blooming of dinoflagellates in the relevant waters. This study focused on the appearance and toxicological characteristics of a toxic dinoflagellate, Alexandrium tamarense, identified and isolated from the Drake Passage in a research cruise from November to December 2001 The appearance of A. tamarense in the Southern Ocean indicates the risk of a paralytic shellfish poisoning (PSP) outbreak there and is therefore of scientific concern. Results showed that while the overall quantity of A. tamarense in water samples from 30meters below the sea surface often comprised less than 0.1% of the total population of phytoplankton, the highest concentration of A. tamarense (20 cells $L^{-1}$) was recorded in the portion of the Southern Ocean between the southern end of South America and the Falkland Islands. Waters near the Polar Front contained the second highest concentrations of 10-15 cells $L^{-1}$. A. tamarense was however rarely found in waters near the southern side of the Polar Front, indicating that cold sea temperatures near the Antarctic ice does not favor the growth of this dinoflagellate. One strain of A. tamarense from this cruise was isolated and cultured for further study in the laboratory. Experiments showed that this strain of A. tamarense has a high tolerance to temperature variations and could survive at temperatures ranging from $5-26^{\circ}C$. This shows the cosmopolitan nature off. tamarense. With regard to the algal toxins produced, this strain of A. tamarense produced mainly C-2 toxins but very little saxitoxin and gonyailtoxin. The toxicological property of this A. tamarense strain coincided with a massive death of penguins in the Falkland Islands in December 2002 to January 2003.

Steady-State and Transient Performance Simulation of a Turboshaft Engine with a Free Power Turbine

King, Chang-Duk,Chung, Suk-Choo The Korean Society of Mechanical Engineers 2000 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.14 No.11

A program of steady-state and transient performance analysis for a 200kW-class small turboshaft engine with free power turbine was developed. An existing turbojet engine was used for the gas generator of the developed turboshaft engine, which was modified to satisfy performance requirements of this turboshaft engine. To verify the accuracy of steady-state performance program for this engine: the program was applied to the gas turbine test unit of the same type, and the analysis results were compared with experimental results. The developed transient performance analysis program using the CMF (Constant Mass Flow) method was utilized to analyze the cases of step increase and ramp increase of the fuel.

Nanofibrous scaffolds electrospun from elastomeric biodegradable poly(L-lactide-co-ϵ-caprolactone) copolymer

Chung, Sangwon,Moghe, Ajit K,Montero, Gerardo A,Kim, Soo Hyun,King, Martin W Institute of Physics Pub 2009 Biomedical materials Vol.4 No.1

<P>Electrospinning has recently received much attention in biomedical applications, and has shown great potential as a novel scaffold fabrication method for tissue engineering. The nano scale diameter of the fibers produced and the structure of the web resemble certain supramolecular features of extracellular matrix which is favorable for cell attachment, growth and proliferation. There are various parameters that can alter the electrospinning process, and varying one or more of these conditions will result in producing different nanofibrous webs. So the aim of this study was to investigate the effect of material variables and process variables on the morphology of electrospun 50:50 poly(L-lactide-co-ϵ-caprolactone) (PLCL) nanofibrous structures. The morphology of the nanofibers produced was strongly influenced by parameters such as the flow rate of the polymer solution, the electrospinning voltage and the solution concentration. The diameter was found to increase with solution concentration in a direct linear relationship. Finally, it has been successfully demonstrated that by increasing the rotation speed of the collector mandrel, the alignment of the fibers can be controlled in a preferred direction. These findings contribute to determining the functional conditions to electrospin this biodegradable elastomeric copolymer which has potential as a scaffold material for vascular tissue engineering.</P>

합성가스 정제용 코팅 금속필터의 분진제거 성능 특성

정석우(Chung Seok Woo),전동환(Jeon Dong Hwan),류상오(Ryu Sang Oh),권인구(Kwon In Goo),김덕연(Kim Duck Yeon),김용택(King Yong Taek) 한국에너지기후변화학회 2016 한국에너지기후변화학회 학술대회 Vol.2016 No.11

Risk, Mechanisms and Implications of Asthma-Associated Infectious and Inflammatory Multimorbidities (AIMs) among Individuals With Asthma: a Systematic Review and a Case Study

Kwon Jung Hyun,Wi Chung-Il,Seol Hee Yun,Park Miguel,King Katherine,Ryu Euijung,Sohn Sunghwan,Liu Hongfang,Juhn Young J. 대한천식알레르기학회 2021 Allergy, Asthma & Immunology Research Vol.13 No.5

Our prior work and the work of others have demonstrated that asthma increases the risk of a broad range of both respiratory (e.g., pneumonia and pertussis) and non-respiratory (e.g., zoster and appendicitis) infectious diseases as well as inflammatory diseases (e.g., celiac disease and myocardial infarction [MI]), suggesting the systemic disease nature of asthma and its impact beyond the airways. We call these conditions asthma-associated infectious and inflammatory multimorbidities (AIMs). At present, little is known about why some people with asthma are at high-risk of AIMs, and others are not, to the extent to which controlling asthma reduces the risk of AIMs and which specific therapies mitigate the risk of AIMs. These questions represent a significant knowledge gap in asthma research and unmet needs in asthma care, because there are no guidelines addressing the identification and management of AIMs. This is a systematic review on the association of asthma with the risk of AIMs and a case study to highlight that 1) AIMs are relatively under-recognized conditions, but pose major health threats to people with asthma; 2) AIMs provide insights into immunological and clinical features of asthma as a systemic inflammatory disease beyond a solely chronic airway disease; and 3) it is time to recognize AIMs as a distinctive asthma phenotype in order to advance asthma research and improve asthma care. An improved understanding of AIMs and their underlying mechanisms will bring valuable and new perspectives improving the practice, research, and public health related to asthma.

Anti-cancer Effects of a Novel Quinoline Derivative 83b1 on Human Esophageal Squamous Cell Carcinoma through Down-Regulation of COX-2 mRNA and PGE2

Ivan Ho Yuen Pun,Dessy Chan,Sau Hing Chan,Po Yee Chung,Yuanyuan Zhou,Simon Law,Alfred King Yin Lam,Chung Hin Chui,Albert Sun Chi Chan,Kim Hung Lam,Johnny Cheuk On Tang 대한암학회 2017 Cancer Research and Treatment Vol.49 No.1

Purpose 83b1 is a novel quinoline derivative that has been shown to inhibit cancer growth in human esophageal squamous cell carcinoma (ESCC). This study was conducted to comprehensively evaluate the cytotoxic effects of 83b1 on a series of ESCC cell lines and investigate the mechanisms by which 83b1 suppresses cancer growth based on molecular docking analysis. Materials and Methods A series of ESCC and nontumor immortalized cell lines were exposed to 83b1 and cisplatin (CDDP) in a dose-dependent manner, and the cytotoxicity was examined by a MTS assay kit. Prediction of the molecular targets of 83b1 was conducted by molecular docking analysis. Expression of cyclooxygenase 2 (COX-2) mRNA and COX-2–derived prostaglandin E2 (PGE2) were measured by quantitative real-time polymerase chain reaction and enzymelinked immuno-sorbent assay, respectively. In vivo anti-tumor effect was determined using a nude mice xenografted model transplanted with an ESCC cell line, KYSE-450. Results 83b1 showed the significant anti-cancer effects on all ESCC cell lines compared to CDDP; however, 83b1 revealed much lower toxic effects on non-tumor cell lines than CDDP. The predicted molecular target of 83b1 is peroxisome proliferator-activated receptor delta (PPAR), which is a widely known oncoprotein. Additionally the expression of COX-2 mRNA and COX-2–derived PGE2 were down-regulated by 83b1 in a dose-dependent manner in ESCC cell lines. Furthermore, 83b1 was shown to significantly reduce the tumor size in nude mice xenograft. Conclusion The results of this study suggest that the potential anti-cancer effects of 83b1 on human esophageal cancers occur through the possible oncotarget, PPAR, and down-regulation of the cancer related genes and molecules.

Clinical Outcomes and Cost-Effectiveness of Osteoporosis Screening With Dual-Energy X-ray Absorptiometry

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.