Fabrication and Pore Characteristics of Cu Foam by Slurry Coating Process

Park, Dahee,Jung, Eun-Mi,Yang, Sangsun,Yun, Jung-Yeul The Korean Powder Metallurgy Institute 2015 한국분말재료학회지 (KPMI) Vol.22 No.2

Metallic porous materials have many interesting combinations of physical and geometrical properties with very low specific weight or high gas permeability. In this study, highly porous Cu foam is successfully fabricated by a slurry coating process. The Cu foam is fabricated specifically by changing the coating amount and the type of polyurethane foam used as a template. The processing parameters and pore characteristics are observed to identify the key parameters of the slurry coating process and the optimized morphological properties of the Cu foam. The pore characteristics of Cu foam are investigated by scanning electron micrographs and micro-CT analyzer, and air permeability of the Cu foam is measured by capillary flow porometer. We confirmed that the characteristics of Cu foam can be easily controlled in the slurry coating process by changing the microstructure, porosity, pore size, strut thickness, and the cell size. It can be considered that the fabricated Cu foams show tremendous promise for industrial application.

Corchorus olitorius Ethanolic Extract has Anti-inflammatory and Wound Healing Effects in vitro

Dahee Lee,Jnhong Park,Youngmin Park,Taejin Kang,Kiman Lee 한국원예학회 2023 한국원예학회 학술발표요지 Vol.2023 No.5

Revealing Strong Metal Support Interaction during CO Oxidation with Metal Nanoparticle on Reducible Oxide Substrates

Dahee Park,Sun Mi Kim,Kamran Qadir,Jeong Young Park 한국진공학회 2013 한국진공학회 학술발표회초록집 Vol.2013 No.2

갑상선 수술 시 근전도튜브를 이용한 신경모니터링

박다희(Dahee Park),성의숙(Eui-Suk Sung) 대한신경모니터링학회 2022 Journal of Neuromonitoring & Neurophysiology Vol.2 No.2

Thyroid surgery can cause many complications, but recurrent laryngeal nerve palsy is the most important. Therefore, many efforts have been tried to avoid recurrent laryngeal nerve palsy. Among them, intraoperative neuromonitoring (IONM) is one of the useful tools to find nerves and avoid nerve palsy during surgery. There are various methods, but the method of directly monitoring the movement of the vocal cords using an electromyography tube was introduced first. After that, a method of increasing the signal accuracy by using a pressure sensor and an accelerometer sensor was also introduced. In addition, a needle is directly pierced into the thyroid cartilage or an electrical signal is measured by attaching a sensor to the skin in front of the thyroid cartilage. Various methods of IONM are being tried and studied, and efforts to help find nerves through IONM are continuing. It is expected that overall surgical complications will be reduced by preserving nerves, avoiding changes in voice and swallowing disorders, and reducing the need for tracheostomy due to bilateral vocal cord palsy.

Construction of an Electrocardiogram Database Including 12 Lead Waveforms

Chung, Dahee,Choi, Junggu,Jang, Jong-Hwan,Kim, Tae Young,Byun, JungHyun,Park, Hojun,Lim, Hong-Seok,Park, Rae Woong,Yoon, Dukyong Korean Society of Medical Informatics 2018 Healthcare Informatics Research Vol.24 No.3

<P><B>Objectives</B></P><P>Electrocardiogram (ECG) data are important for the study of cardiovascular disease and adverse drug reactions. Although the development of analytical techniques such as machine learning has improved our ability to extract useful information from ECGs, there is a lack of easily available ECG data for research purposes. We previously published an article on a database of ECG parameters and related clinical data (ECG-ViEW), which we have now updated with additional 12-lead waveform information.</P><P><B>Methods</B></P><P>All ECGs stored in portable document format (PDF) were collected from a tertiary teaching hospital in Korea over a 23-year study period. We developed software which can extract all ECG parameters and waveform information from the ECG reports in PDF format and stored it in a database (meta data) and a text file (raw waveform).</P><P><B>Results</B></P><P>Our database includes all parameters (ventricular rate, PR interval, QRS duration, QT/QTc interval, P-R-T axes, and interpretations) and 12-lead waveforms (for leads I, II, III, aVR, aVL, aVF, V1, V2, V3, V4, V5, and V6) from 1,039,550 ECGs (from 447,445 patients). Demographics, drug exposure data, diagnosis history, and laboratory test results (serum calcium, magnesium, and potassium levels) were also extracted from electronic medical records and linked to the ECG information.</P><P><B>Conclusions</B></P><P>Electrocardiogram information that includes 12 lead waveforms was extracted and transformed into a form that can be analyzed. The description and programming codes in this case report could be a reference for other researchers to build ECG databases using their own local ECG repository.</P>

Placental angiogenic factors : Useful factor for prediction of preeclampsia abut not of small for gestational

( Dahee Kim ),( Sohyun Shim ),( Soohyun Kim ),( Jiyeon Kim ),( Yeonkyung Cho ),( Sungshin Shim ),( Kyoungjin Lee ),( Donghyun Cha ),( Heejin Park ) 대한산부인과학회 2016 대한산부인과학회 학술대회 Vol.102 No.-

목적: To investigate the value of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) for predicting preeclampsia or small for gestational age (SGA) in pregnant women. 방법: This prospective cohort single center study was conducted in 474 women with singleton pregnancy. We measured plasma levels of pregnancy- associated plasma protein-A(PAPP-A), serum levels of alpha-fetoprotein (MSAFP), unconjugated estriol (uE3), inhibin-A and human chorionic gonadotropin (hCG) at 15+0 to 20+6 weeks of gestation. We also assessed the plasma levels of sFlt-1 and PlGF at 24+0 to 28+6 and 29+0 to 37+6 weeks of gestation, using the Elecsys assay and calculated sFlt-1/PlGF ratio. Uterine artery doppler ultrasonography with color flow mapping was performed at 20+0 to 24+6 weeks of gestation. 결과: Respectively, 29 and 19women had SGA fetus or preeclampsia comparing to 426 uncomplicated pregnant women with AGA fetus. In PE group, the level of sFlt-1 and sFlt-1/PlGF ratio were higher (2nd : 2630.5 vs 1389, 10 vs 2.6, p<0.05; 3rd : 7295 vs 2386, 83.7 vs 8.25, p<0.05) and the level of PlGF was significantly lower (2nd : 215.9 vs 530.1, p<0.05; 3rd : 119.9 vs 294.95, p<0.05) than control group in 2nd trimester and 3rd trimester. However, in SGA group, these factors didn’t show significant difference in both second trimester and third trimester. The time-dependent slope of the sFlt-1/PlGF ratio between 2nd and 3rd trimester was significantly steeper in PE compared to control and SGA group. Such as Uterine artery resistance index, pulsatility index and S/D ratio in SGA group, but not in PE group. 결론: Measurements of PlGF, sFlt-1 and sFlt-1/PlFT ratio were useful markers for the prediction of preeclampsia but not of SGA.

Size effects of micro-pattern on lithium metal surface on the electrochemical performance of lithium metal secondary batteries

Park, Joonam,Kim, Dohwan,Jin, Dahee,Phatak, Charudatta,Cho, Kuk Young,Lee, Young-Gi,Hong, Seungbum,Ryou, Myung-Hyun,Lee, Yong Min Elsevier 2018 Journal of Power Sources Vol.408 No.-

<P><B>Abstract</B></P> <P>Two micro-patterns of different sizes (50 and 80 μm) are designed to have equivalent capacities of 1.06 and 2.44 mAh cm<SUP>−2</SUP> by building a computational battery model. After preparing two stamps each possessing a micro-pattern design, the corresponding pattern is properly imprinted on the surface of 100 μm lithium metal, which is confirmed by scanning electron microscopy. When both micro-patterned lithium metals are electrochemically reduced and oxidized up to 1 mAh cm<SUP>−2</SUP> in Li/Li symmetric cells at 1 or 2 mA cm<SUP>−2</SUP>, the 80 μm-patterned lithium shows a more stabilized lower overpotential during long-term cycling than the 50 μm-patterned and bare lithium, probably due to the lithium anchoring effect and a larger empty volume in the patterns. Additionally, an overflow of lithium deposits is easily observed in the 50 μm-patterned lithium metal, while the 80 μm-patterned lithium metal holds most of the lithium deposits within the patterns. When both micro-patterned lithium metals are assembled to full cells with a LiNi<SUB>0·6</SUB>Co<SUB>0·2</SUB>Mn<SUB>0·2</SUB>O<SUB>2</SUB> cathode of 2 mAh cm<SUP>−2</SUP>, the 80 μm-patterned lithium metal shows much better electrochemical performances with stable plating/stripping behavior within the patterns.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New micro-pattern computationally designed to increase lithium deposition. </LI> <LI> The new pattern on lithium metal lowers overpotential during galvanostatic cycling. </LI> <LI> Cycle life is greatly improved for 200 cycles at high current density. </LI> <LI> The micro-pattern design suppresses undesirable lithium plating and stripping. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

DLNA-based Home Network Integrated System for I-Safety

Dahee Jeong,Yong-Suk Park,Hyun-Sik Kim,Chong Ho Yoon 한국정보통신학회 2015 2016 INTERNATIONAL CONFERENCE Vol.7 No.1

In this paper, a Digital Living Network Alliance (DLNA) guidelines based integrated home network is proposed which combines sensor networks and multimedia networks to provide indoor safety (I-Safety) services. In the proposed system, the Simple Service Discovery Protocol (SSDP) used in DLNA is modified to include sensor status data, and a gateway device is used to relay the information to the multimedia network. By aggregating detected sensor information to the DLNA network, the user can be aware of emergency situations, such as fire or intrusion detection, even when he or she is deeply immersed in multimedia contents consumption.

Evaluation on Four Volatile Organic Compounds (VOCs) Contents in the Groundwater and Their Human Risk Level

Dahee Song,Sunhwa Park,Sang-Ho Jeon,Jong Yeon Hwang,Moonsu Kim,Hun-Je Jo,Deok-Hyun Kim,Gyeong-Mi Lee,Ki-In Kim,Hye-Jin Kim,Tae-Seung Kim,Hyen Mi Chung,Hyun-Koo Kim 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.4

In this study, we monitored 4 volatile organic compounds (VOCs) such as chloroform, dichloromethane, 1,2-dichloroethane, and tetrachloromethane in groundwater samples to determine the detection frequency and their concentrations and evaluated the health risk level considering ingestion, inhalation, and skin contact. 75 groundwater wells were selected. 24 wells were from monitoring background groundwater quality level and 51 wells were from monitoring groundwater quality level in industrial or contamination source area. In the results, the detection frequency for chloroform, dichloromethane, 1,2-dichloroethane, and tetrachloromethane was 42.3%, 8.1%, 6.0%, and 3.4%, respectively. The average concentrations of VOCs were high in the order of chloroform (1.7 μg L<SUP>-1</SUP>), dichloromethane (0.08 μg L<SUP>-1</SUP>), tetrachloromethane (0.05 μg L<SUP>-1</SUP>), and 1,2-dichloroethane (0.05 μg L<SUP>-1</SUP>). Chloroform had the highest detection frequency and average detection concentration. In the contaminated groundwater, the detection frequency of VOCs was high in the order of chloroform, dichloromethane, 1,2-dchloroethane, and tetrachloromethane. The average concentrations for chloroform, dichloromethane, 1,2-dichloroethane, and tetrachloromethane were 2.23 μg L<SUP>-1</SUP>, 0.08 μg L<SUP>-1</SUP>, 0.07 μg L<SUP>-1</SUP>, and 0.06 μg L<SUP>-1</SUP>, respectively. All the 4 compounds were detected at industrial complex and storage tank area. The maximum concentration of chloroform, dichloromethane, and 1,2-dichloroethane was detected at industrial complex area. Especially, the maximum concentration of chloroform and dichloromethane was detected at a chemical factory area. In the uncontaminated groundwater, the detection frequency of VOCs was high in the order of chloroform, dichloromethane, and 1,2-dchloroethane and tetrachloromethane was not detected. The average concentrations for chloroform, dichloromethane, and 1,2-dichloroethane were 0.57 μg L<SUP>-1</SUP>, 0.07 μg L<SUP>-1</SUP>, and 0.03 μg L<SUP>-1</SUP>, respectively. Although chloroform in the uncontaminated groundwater was detected the most, the concentration of chloroform was not exceeding water quality standards. By land use, the maximum detection frequency of 1,2-dichloroethane was found near a traffic area. For human risk assessment, the cancer risk for the 4 VOCs was 1<SUP>0-6</SUP>~10<SUP>-9</SUP>, while the non-cancer risk (HQ value) for the 4 VOCs is 10<SUP>-2</SUP>~10<SUP>-3</SUP>.

Simultaneous Analysis of 13 Pesticides in Groundwater and Evaluation of its Persistent Characteristics

Dahee Song,Sunhwa Park,Sang-Ho Jeon,Ki-In Kim,Jong Yeon Hwang,Moonsu Kim,Hun-Je Jo,Deok-hyun Kim,Gyeong-Mi Lee,Hye-Jin Kim,Tae-Seung Kim,Hyen Mi Chung,Hyun-Koo Kim 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.5

For this study, groundwater samples for 3 years from 2011 through 2013 were collected at 106 groundwater monitoring site in Korea. These groundwater samples were analyzed for 13 pesticides such as cabofuran, pentachlorobenzene, hexachlorobenzene, simazine, atrazine, lindane (gamma-HCH), alachlor, heptachlor, chlordane (total), endosulfan (1, 2), dieldrin, endrin, 4,4-DDT. The objectives of this study were to determine the detection frequency and their concentrations of 13 pesticides and evaluate the health risk level considering ingestion, inhalation, and skin contact using concentrations of 13 pesticides in groundwater samples. An analysis was used for the simultaneous determination for 13 pesticides using GC-MS. GC-MS was performed on HP-5ms, using helium (1 ml min<SUP>-1</SUP>) as carrier gas. The average recoveries of the pesticides were from 92.8% to 120.8%. The limits of detection (LODs) were between 0.004 μg L<SUP>-1</SUP> and 0.118 μg L<SUP>-1</SUP> and the limits of quantification (LOQs) were between 0.012 μg L<SUP>-1</SUP> and 0.354 μg L<SUP>-1</SUP>. 106 groundwater wells were selected. 54 wells were from well to monitor background groundwater quality and 52 wells were from well to monitor groundwater quality in industrial or contamination source area. Eight pesticides including pentachlorobenzene, lindane (Gamma-HCH), heptachlor, chlordane (total), Endosulfan (1, 2), dieldrin, endrin, and 4,4-DDT were not detected in groundwater samples. The detection frequency for hexachlorobenzene, alachlor, carbofuran and simazine was 23.4%, 11.4%, 7.3%, and 1.0%, respectively. Atrazine was detected once in 2011. The average concentrations were 0.00423 μg L<SUP>-1</SUP> for carbofuran, 0.000243 μg L<SUP>-1</SUP> for alachlor, 0.00015 μg L<SUP>-1</SUP> for simazine, and 0.00001 μg L<SUP>-1</SUP> for hexachlorobenzene. The detection frequency of hexachlorobenzene was high, but the average concentration was low. In the contaminated groundwater, the detection frequency for hexachlorobenzene, alachlor, carbofuran, simazine and atrazine was 26.1%, 21.3%, 7.1%, 1.9% and 0.3%, respectively. In the uncontaminated groundwater, detection frequency for hexachlorobenzene, carbofuran and alachlor were 20.2%, 7.5%, and 1.9% respectively. Simazine and atrazine were not detected at uncontaminated groundwater wells. According to the purpose of groundwater use, atrazine was detected for agricultural groundwater use. Hexachlorobenzene showed high detection frequency at agricultural groundwater use area where the animal feeding area and golf course area were located. Alachlor showed more than 50% detection frequency at cropping area, pollution concern river area, and golf course area. Atrazine was detected in agricultural water use area. By land use, the maximum detection frequency of alachlor was found near an orchard. For human risk assessment, the cancer risk for the 5 pesticides was between 10<SUP>-7</SUP> and 10<SUP>-10</SUP>, while the non-cancer risk (HQ value) was between 10<SUP>-4</SUP> and 10<SUP>-6</SUP>. For conclusion, these monitoring study needs to continue because of the possibility of groundwater contamination based on various purpose of groundwater use.