Ultrasonic Degradation of Endocrine Disrupting Compounds in Seawater and Brackish Water

So Young Park,Jong Sung Park,Ha Yoon Lee,Ji Yong Heo,Yeo Min Yoon,Kyung Ho Choi,Nam Guk Her 대한환경공학회 2011 Environmental Engineering Research Vol.16 No.3

In this study, a series of experiments was conducted on the relative degradation of commonly known endocrine-disrupting compounds such as bisphenol A (BPA) and 17α-ethinyl estradiol (Ee₂) in a single-component aqueous solution using 28 and 580 kHz ultrasonic reactors. The experiments were conducted with three different types of model water: deionized water (DI), synthetic brackish water (SBW), and synthetic seawater (SSW) at pH 4, 7.5, and 11 in the presence of inert glass beads and humic acids. Significantly higher sonochemical degradation (93-97% for BPA) occurred at 580 kHz than at 28 kHz (43-61% for BPA), regardless of water type. A slightly higher degradation was observed for Ee₂ compared to that of BPA. The degradation rate of BPA and Ee₂ in DI water, SBW, and SSW after 30 min of ultrasound irradiation at 580 kHz increased slightly with the increase in pH from 4 (0.073-0.091 min-1 for BPA and 0.081-0.094 min-1 for Ee₂) to 7.5 (0.087-0.114 min-1 for BPA and 0.092?0.124 min-1 for Ee₂). In contrast, significant degradation was observed at pH 11 (0.149-0.221 min-1 for BPA and 0.147-0.228 min-1 for Ee₂). For the given frequencies of 28 and 580 kHz, the degradation rate increased in the presence of glass beads (0.1 mm and 25 g) for both BPA and Ee₂: 0.018-0.107 min-1 without beads and 0.052-0.142 min-1 with beads for BPA; 0.021-0.111 min-1 without beads and 0.054-0.136 min-1 with beads for Ee₂. A slight increase in degradation of both BPA and Ee₂ was found as the concentration of dissolved organic carbon (DOC, humic acids) increased in both SBW and SSW: 0.107-0.115 min-1 in SBW and 0.087-0.101 min-1 in SSW for BPA; 0.111-0.111 min-1 in SWB and 0.092-0.105 min-1 in SSW for Ee₂. After 30 min of sonicating the humic acid solution, DOC removal varied depending on the water type: 27% (3 mg L-1) and 7% (10 mg L-1) in SBW and 7% (3 mg L-1) and 4% (10 mg L-1) in SSW.

Development of Simultaneous Analytical Method for ImidazolinoneHerbicides from Livestock using LC-MSMS

Hyo-Min Heo,Hyeong-WookJo,Kyu-Won Hwang,Jung-Hun Sun,Joon-Kwan Moon 한국농약과학회 2021 한국농약과학회 학술발표대회 논문집 Vol.2021 No.11

Simultaneous analytical method using LC/MSMS for imidazolinone herbicides from livestock (egg, milk, beef, pork and chicken) for monitoring was developed with QuEChERS preparation. Sample weighing (5g) in a 50mL conical tube, added 0.1 M potassium phosphate dibasic solution (5mL) was shaken for 10min. After 0.5mL 6 NHCl, 10mL acetonitrile were added, it was shaken for 10min. And QuEChERS extraction salt (Original method, 4g MgSO₄, 1g NaCl) were added to the sample in the 50 mL conical tube. The mixture was strongly shaken for 1 min and was centrifuged at 3,000g for 10 min. The acetonitrile layer was purification with dSPE (150mg MgSO₄, 25mg C18) and was centrifuged at 13,000g for 5min. The supernatant was filtered with a membrane filters (pore size: 0.2um) before analysis. ME (%, Matrix effect) for almost analytes range were -6.56 to 5.70%. MLOD (Method LOD) and MLOQ (Method LOQ) was calculated by S/N ratio. MLOQs were 0.01 mg/kg. The linear correlation coefficients (r2) were > 0.99 within the range of 2 ~ 100 ug/kg for all of the 3 imidazolinone herbicides. The percentages (of imidazolinone herbicides) recovers were in the range of 84.1 ~ 110.6% (0.01mg/kg level), 90.8 ~ 97.1% (0.1mg/kg level) and 94.4 ~ 102.1% (0.5mg/kg level) within the validation criteria (recover; 70-120% with RSD < 20%)

Inhibition of Clostridium perfringens using Bacteriophages and Bacteriocin Producing Strains

Sunhak Heo,Min Gon Kim,Mirae Kwon,Hee Soo Lee,Geun-Bae Kim 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.1

In this study, we isolated and characterized a bacteriocin-producing strain and two bacteriophages (P4, A3), showing antimicrobial effects against Clostridium perfringens, from chicken and swine feces by the spot-on-the lawn antagonism method. The selected strain was identified as Streptococcus hyointestinalis by 16S rRNA gene sequencing. The bacteriocin from the isolated strain exhibited strong inhibitory activity against four strains of C. perfringens and all the tested strains of Listeria monocytogenes, and the bacteriocin were highly heat- and pH-stable even at pH 2, pH 10 and 121°C for 15 min. We also evaluated the combined effects of the isolated bacteriocin and phages. Combining the phage treatments and bacteriocin resulted in a synergetic effect compared with the phage or the bacteriocin alone. In addition, during the probiotic test, the bacteriocin-producing S. hyointestinalis B19 strain reduced the population of C. perfringens significantly. Treatment with S. hyointestinalis B19 and a cocktail of lytic bacteriophages eradicated the C. perfringens KCTC 3269T, completely. Consequently, the isolated bacteriocin and bacteriophages represent candidates for effective biocontrol of C. perfringens, and bacteriocin-producing S. hyointestinalis B19 is a potential probiotic candidate for use in domestic animals.

석면함유 슬레이트 지붕 물받이 퇴적물 중 석면 섬유 함유율

임지현,한솔민,김현석,신유민,박시은,허정윤,김민영,장봉기 순천향대학교 기초과학연구소 2022 순천향자연과학연구 논문집 Vol.28 No.1,2

This study attempted to determine the degree of asbestos release from the aging slate roof by comparing the asbestos content in the slate roof rain gutter with a colored steel plate (tin plate) over the slate roof. Four slate roof houses located in Haengmok-ri, Asan-si, Chungcheongnam-do, and one house constructed with a colored steel plate on the slate roof were selected to collect the sediment of the roof rain gutter. The asbestos fiber content was calculated by a point counting method using a polarization microscope after pretreatment with conversion treatment and hydrochloric acid treatment. The average asbestos content of the four slate roof rain gutter were 1.89%. However, asbestos was not detected in the Slate covering roof rain gutter, which were constructed on the slate roof. Asbestos fiber content was the highest at 2.89% in the slate roof rain gutter installed in 1976, followed by 2.44% in 1953. From the above results, it is necessary to minimize secondary damage as asbestos fibers released from slate roof houses to the surrounding atmosphere or leaked from slate roofs as rainwater may cause soil pollution and seriously affect residents' health. Although covering with colored steel plates (tin plates) has been shown to prevent the leakage of asbestos fibers to some extent, it is believed that a policy alternative to remove the slate roof as soon as possible is needed to solve the fundamental problem.

상대습도 및 저장 온도가 분말녹차의 품질에 미치는 영향

이정민(Jung-Min Lee),임상욱(Sang-Wook Lim),조성환(Sung-Hwan Cho),최성길(Sung-Gil Choi),허호진(Ho-Jin Heo),이승철(Seung-Cheol Lee) 한국식품영양과학회 2009 한국식품영양과학회지 Vol.38 No.1

분말 녹차를 상대습도(23, 69, 81%)와 온도(-20, 4, 20℃)를 달리하여 3달간 저장한 후, 1.5 g에 100 mL을 첨가하여 추출물을 제조하여 총 페놀 함량, 총 플라바놀 함량, 아스코르브산 함량, 카테킨 함량의 변화를 조사하였다. 상대습도 23%, 4℃의 조건에 저장한 경우에서 총 페놀 함량, 총 플라바놀 함량, 아스코르브산 함량이 가장 높았는데 각각 287.1 ㎎/g, 44.9 ㎎/g, 36.9 ㎎/g의 값을 보였다. 이는 저장 초기의 각각의 측정값인 267.5 ㎎/g, 49.4 ㎎/g, 24.2 ㎎/g에 비해 총 페놀과 아스코르브산은 증가하였고, 총 플라바놀 함량은 감소하였다. 카테킨류의 경우에도 상대습도 23%, 4℃에 저장하였을 때 가장 높았는데 주된 카테킨인 EGC와 EGCG는 초기의 16.9와 27.3 ㎎/g에서 3달 후에는 각각 24.3과 36.5 ㎎/g으로 증가하였다. 또한 카페인도 같은 조건에서 초기의 20.7 ㎎/g에서 3달 후에는 30.7 ㎎/g으로 증가하였다. 그러나 상대습도가 높고 온도가 -20℃나 20℃에 저장한 경우에는 상대적으로 각 성분들이 감소하는 경향을 나타내었다. 이러한 결과는 분말 녹차의 상대습도와 저장 온도가 녹차의 품질 보존에 매우 중요하며, 낮은 습도에서 냉장 상태로 저장하는 것이 녹차의 품질 유지에 유리함을 의미한다. After storing green tea powder for three months at three different temperatures (-20, 4, and 20℃) with three different relative humidities (RHs) (23, 69, and 81%), the chemical quality was evaluated with green tea, which was prepared by soaking 1.5 g of the powder into 100 mL of distilled water at 70℃ for 5 min. Total phenolic contents, total flavanol contents, and ascorbic acid contents of green tea powder stored at 4℃ with 23% RH changed from 267.5, 49.4, and 24.2 ㎎/g to 287.1, 44.9, and 36.9 ㎎/g, respectively, compared to the powder before storage. EGC and EGCG, the main catechins of green tea, also changed from 16.9 and 27.3 ㎎/g to 24.3 and 36.5, g/g, respectively, after storage for 3 months at 4℃ with 23% RH. However, when the green tea powder was stored at -20 or 20oC with higher RH such as 69 and 81%, the chemical compounds were significantly decreased. The results indicate that temperature and RH are important during storage of green tea powder, and low RH and refrigerated condition (-4oC) are preferable to increase or preserve the chemical compounds of the tea.

Biliary Self-Expandable Metal Stent Could Be Recommended as a First Treatment Modality for Immediate Refractory Post-Endoscopic Retrograde Cholangiopancreatography Bleeding

Sun Young Moon,Jun Heo,Min Kyu Jung,Chang Min Cho 대한소화기내시경학회 2022 Clinical Endoscopy Vol.55 No.1

Background/Aims: Recent reports suggest that the biliary self-expandable metallic stent (SEMS) is highly effective for maintaininghemostasis when endoscopic hemostasis fails in endoscopic retrograde cholangiopancreatography (ERCP)-related bleeding. Wecompared whether temporary SEMS offers better efficacy than angioembolization for refractory immediate ERCP-related bleeding. Methods: Patients who underwent SEMS placement or underwent angioembolization for bleeding control in refractory immediateERCP-related bleeding were included in the retrospective analysis. We evaluated the hemostasis success rate, severity of bleeding,change in hemoglobin levels, amount of transfusion, and delay to the start of hemostasis. Results: A total of 27 patients with SEMS and 13 patients who underwent angioembolization were enrolled. More transfusionswere needed in the angioembolization group (1.0±1.4 units vs. 2.5±2.0 units; p=0.034). SEMS failure was successfully rescued byangioembolization. The partially covered SEMS (n=23, 85.1%) was generally used, and the median stent-indwelling time was 4 days. The mean delay to the start of angioembolization was 95.2±142.9 (range, 9–491) min. Conclusions: Temporary SEMS had similar results to those of angioembolization (96.3% vs. 92.3%; p=0.588). Immediate SEMSinsertion is considered a bridge treatment modality for immediate refractory ERCP-related bleeding. Angioembolization still has arole as rescue therapy when SEMS does not work effectively.

Brugada 증후군 환자의 경접형동 선종절제술을 위한 마취 경험

허민정,김세연 영남대학교 의과대학 2009 Yeungnam University Journal of Medicine Vol.26 No.2

Brugada syndrome is characterized by an ECG pattern of right bundle branch block and ST segment elevation in the right precordial leads (V1-V3) without structural heart disease. It is also characterized by sudden cardiac death that’s caused by ventricular fibrillation. This is a familial syndrome with an autosomal dominant inheritance pattern and it may be considerably more common in Southeast Asia. Many factors during anesthesia can precipitate malignant dysrrhythmia in these patients, so careful choice of anesthetics is required. We experienced a case of Brugada syndrome in a 59-year-old male patient who was under general anesthesia for trans-sphenoidal surgery to treat a pituitary adenoma, and the patient was diagnosed as having Brugada syndrome without any untoward cardiovascular events.

편평세포암종 임파절 전이에 대한 인공 신경망 시스템의 진단능 평가

허민석,박태원,박상욱,유동수,이삼선,최순철 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.1

Purpose: The purpose of this study was to evaluate cervical lymph node metastasis of oral squamous cell carcinoma patients by MRI film and neural network system. Materials and Methods: The oral squamous cell carcinoma patients(21 patients, 59 lymph nodes) who have visited SNU hospital and been taken by MRI, were included in this study. Neck dissection operations were done and all of the cervical lymph nodes were confirmed with biopsy. In MR images, each lymph node were evaluated by using 6 MR imaging criteria(size, roundness, heterogeneity, rim enhancement, central necrosis, grouping) respectively. Positive predictive value, negative predictive value, and accuracy of each MR imaging criteria were calculated. At neural network system, the layers of neural network system consisted of 10 input layer units, 10 hidden layer units and 1 output layer unit. 6 MR imaging criteria previously described and 4 MR imaging criteria (site I-node level II and submandibular area, site II-other node level, shape I-oval, shape II-bean) were included for input layer units. The training files were made of 39 lymph nodes(24 metastatic lymph nodes, 10 non-metastatic lymph nodes) and the testing files were made of other 20 lymph nodes(10 metastatic lymph nodes, 10 non-metastatic lymph nodes). The neural network system was trained with training files and the output level (metastatic index) of testing files were acquired. Diagnosis was decided according to 4 different standard metastatic index-68, 78, 88, 98 respectively and positive predictive values, negative predictive values and accuracy of each standard metastatic index were calculated. Results: In the diagnosis of using single MR imaging criteria, the rim enhancement criteria had highest positive predictive value (0.95) and the size criteria had highest negative predictive value(0.77). In the diagnosis of using single MR imaging criteria, the highest accurate criteria was heterogeneity (accuracy : 0.81) and the lowest one was central necrosis (accuracy : 0.59). In the diagnosis of using neural network systems, the highest accurate standard metastatic index was 78, and that time, the accuracy was 0.90. Neural network system was more accurate than any other single MR imaging criteria in evaluating cervical lymph node metastasis. Conclusion: Neural network system has been shown to be more useful than any other single MR imaging criteria. In future, Neural network system will be powerful aiding tool in evaluating cervical node metastasis.

전지구적 여성주의와 초국가적 여성주의들

허민숙 이화여자대학교 한국여성연구원 2008 여성학논집 Vol.25 No.1

이 글은 전지구적 여성주의(global feminism)와 초국가적 여성주의들(transnationalfeminisms)을 전지구적인 여성에 대한 폭력추방운동과 여성인권개념의 등장과 확산에 초점을 두어 개념화 하는 것을 목적으로 한다. 현재 진행형으로 논의 중인 이 두 여성주의의 영역을 가시화하는데 있어, “여성간 차이 다루기”(dealing with differences among women)를 핵심 개념으로 활용한다. 전지구적 여성주의가 여성간의 차이를 가로지르는 공통성을 추구함으로써 전지구적 네트워크, 연대, 연합을 이루고자 하는 여성주의자들의 노력이라면, 초국가적 여성주의들은 계급, 인종, 성적 지향, 그리고 국가와 관련한 여성간의 차이들을 신중하게 고려함으로써 전지구적 여성주의의 보편적이고도 제국주의적인 일면을 비판적으로 검토하려는 이론적 논의들이다. 한국 여성폭력추방운동의 전개는 바로 이러한 전지구적 여성주의와 초국가적 여성주의들의 논의와 맞닿아 있다. 현 가정폭력방지법의 실행과 집행의 보수화, 아내구타 문제의 비범죄화 경향은 바로 그 법제정을 이뤄냈던 운동당시의 맥락, 그 맥락을 활용한 여성운동의 전략과 관련된다는 점에서 한국여성폭력추방운동의 역사적 전개는 초국가적 여성주의들의 이론적 논의들로부터 평가받을 수 있다. 그러는 동시에, 전지구적 여성주의가 추구하는 보편가치는 우리 문화적 맥락의 한계를 극복하고 여성폭력개념을 정립하는 중요한 정치적 전략이자 목표가 될 수 있다. 이런 점에서 한국의 여성폭력추방운동은 전지구적으로 그리고 초국가적으로 연계되어 있고 그 역사적 진행에 기여할 수 있다. This article aims to conceptualize the notion of global feminism and transnational feminisms by exclusively focusing on the ways in which the issue of "differences among women" has been dealt with within those two on-going feminist thoughts and practices across borders. Identifying global feminism as a feminist attempt to find common ground, despite complicated differences among women, this article explores the ways in which the issue of violence against women has emerged as a common global problem. It also articulates the ways in which a women's human rights discourse has been developed to resist violations of women's rights committed in the name of respecting cultural differences. The UN conferences on women provided a space for discussing women's shared problems and forging feminist alliances across the world. While global feminism is accused of constructing a general causality in order to establish a united, global political force, transnational feminisms attempt to explore possibilities or impossibilities for feminist coalitions across differences. In this sense, the term "transnational feminisms" refers to theoretical dimensions of feminist coalition building around the globe. Although transnational feminisms share with global feminism an emphasis on coalition building, they reject both the universalizing tendency of formulating agendas and oppositional binaries that pervade global feminist projects. Transnational feminisms seek to theorize differences rather than leave behind or celebrate differences. Based on their postcolonial critique, therefore, transnational feminisms attempt to elaborate feminist theories and practical ideas by criticizing and contradicting the universal and imperialist tendencies of global feminism. By briefly presenting an empirical case study of combating violence against women in the South Korean setting, this article addresses the gap in knowledge surrounding the promotion of a universal human rights language as well as locally situated feminist activities, frameworks and decision making. In order to challenge cultural bias and prejudice, which decriminalize wife beating in the name of protecting family values, this article affirms the necessary for Korean feminist activists to employ women's human rights discourse in terms of global justice. On the other hand, this article shows that the contemporary obstacles that the Korean anti-domestic violence movement confronts, in spite of considerable legal reforms, are closely relevant to socio-political and cultural contexts upon which the movement relied and in which the issue of wife beating was constructed as a public one. In this vein, it concludes that the locally-situated Korean women's movement against violence against women can be discussed within global/transnational feminist discourses and practices as it also makes theoretical and practical contributions to the growing field of feminist studies.

인공적 인접면 치아우식증의 구내방사선사진과 디지탈 영상의 진단능 평가

허민석,유동수 大韓口腔顎顔面 放射線學會 1994 Imaging Science in Dentistry Vol.24 No.2

Recently, the digital image was introduced into radiological image. The digital image has the power of contrast enhancement, histogram control, and other digitally enhancement. At the point of the resolution, periapical radiograph is superior to the digital image, but enhanced digital procedure improves the diagnostic ability of the digital image. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries in conventional radiographs, digital radiographs and enhanced digital radiographs (histogram specification). ROC(Receiver Operating Characteristic) analysis and paired t-test were used for the evaluation of detectability, and following results were acquried: 1. The mean ROC area of conventional radiographs was 0.9274. 2. The mean ROC area of unenhanced digital image was 0.9168. 3. The mean ROC area of enhanced digital image was 0.9339. 4. The diagnostic ability of three imaging methods was not significant difference(p>0.05). So, the digital images had similar diagnostic ability of artificial proximal caries to conventional radiographs. If properly enhanced digital image, it may be superior to conventional radiographs.