• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.379-379
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• 2018

MXenes are a new family of 2D transition metal carbide nanosheets analogous to graphene (Lv et al., 2017; Sun et al., 2018). Due to the easy availability, hydrophilic behavior, and tunable chemistry of MXenes, their use in applications for environmental pollution remediation such as heavy metal adsorption has recently been explored (Li et al., 2017). In this study, three-dimensional (3D) MXene ($Ti_3C_2T_x$) films with high adsorption capacity, good mechanical strength, and high selectivity for specific radionuclide from aquose solution were successfully fabricated by a polymeric precursor method using vacuum-assisted filtration. The highest removal efficiency on the films was 99.54%, 95.61%, and 82.79% for $Sr^{2+}$, $Co^{2+}$, and $Cs^+$, respectively, using a film dosage of 0.06 g/ L in the initial radionuclide solution (each radionuclide concentration = 1 mg/L and pH = 7.0). Especially, the adsorption process reached an equilibrium within 30 min. The expanded interlayer spacing of $Ti_3C_2T_x$ sheets in MXene films showed excellent radionuclide selectivity ($Cs^+$ and/or $Sr^{2+}/Co^{2+}$) (Simon, 2017). Besides, the MXene films was not only able to be easily retrieved from an aqueous solution by filtration after decontamination processes, but also to selectively separate desired target radionuclides in the solutions. Therefore, the newly developed MXene ($Ti_3C_2T_x$) films has a great potential for radionuclide removal from aqueous solution.

• Therapeutic Science for Rehabilitation
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• v.12 no.2
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• pp.85-98
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• 2023

Objective : We investigated the efficacy of an artificial intelligence computerized cognitive training program using motion capture to identify changes in cognition, depression, and quality of life in older adults with mild cognitive impairment. Methods : A total of seven older adults (experimental group = 4, control group = 3) participated in this study. During the COVID-19 period from October to December 2021, we used a program, "MOOVE Brain", that we had developed. The experimental group performed the program 30 minutes 3×/week for 1 month. We analyzed patients scores from the Korean version of the Mini-Mental State Examination-2, the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet for Daily Life Evaluation, the short form Geriatric Depression Scale, and Geriatric Quality of Life Scale. Results : We observed positive changes in the mean scores of the Stroop Color Test (attention), Stroop Color/Word Test (executive function), SGDS-K (depression), and GQOL (QoL). However, these changes did not reach statistical significance for each variable. Conclusion : The study results from "MOOVE Brain" can help address cognitive and psychosocial issues in isolated patients with MCI during the COVID-19 pandemic or those unable to access in-person medical services.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.598-604
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• 2008

Background: The improvements in endoscopic equipment and surgical robots has encouraged the performance of minimally invasive cardiac operations. Yet only a few Korean studies have compared this procedure with the sternotomy approach. Material and Method: Between December 2005 and July 2007, 48 patients (group A) underwent minimally invasive cardiac surgery with AESOP through a small right thoracotomy. During the same period, 50 patients (group B) underwent conventional surgery. We compared the operative time, the operative results, the post-operative pain and the recovery of both groups. Result: There was no hospital mortality and there were no significant differences in the incidence of operative complications between the two groups. The operative $(292.7{\pm}61.7\;and\;264.0{\pm}47.9min$, respectively; p=0.01) and CPB times ($128.4{\pm}37.6\;and\;101.7{\pm}32.5min$, respectively; <0.01) were longer for group A, whereas there was no difference between the aortic cross clamp times ($82.1{\pm}35.0\;and\;87.8{\pm}113.5min$, respectively; p=0.74) and ventilator times ($18.0{\pm}18.4\;and\;19.7{\pm}9.7$ hr, respectively; p=0.57) between the groups. The stay on the ICU $(53.2{\pm}40.2\;and\;72.8{\pm}42.1hr$, respectively; p=0.02) and the hospitalization time ($9.7{\pm}7.2\;and\;14.8{\pm}11.9days$, respectively; p=0.01) were shorter for group A. The Patients in group B had more transfusions, but the difference was not significant. For the overall operative intervals, which ranged from one to four weeks, the pair score was significantly lower for the patients of group A than for the patients of group B. In terms of the postoperative activities, which were measured by the Duke Activity Scale questionnaire, the functional status score was clearly higher for group A compared to group B. The analysis showed no difference in the severity of either post-repair of mitral ($0.7{\pm}1.0\;and\;0.9{\pm}0.9$, respectively; p=0.60) and tricuspid regurgitation ($1.0{\pm}0.9\;and\;1.1{\pm}1.0$, respectively; p=0.89). In both groups, there were no valve related complications, except for one patient with paravalvular leakage in each group. Conclusion: These results show that compared with the median sternotomy patients, the patients who underwent minimally invasive surgery enjoyed significant postoperative advantages such as less pain, a more rapid return to full activity, improved cosmetics and a reduced hospital stay. The minimally invasive surgery can be done with similar clinical safety compared to the conventional surgery that's done through a median sternotomy.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.195-200
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• 2015

The objective of this study was to evaluate the toxicities of permeable cryoprotectants and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology (ART). Toxicities of permeable cryoprotectants, dimethyl sulfoxide (DMSO), ethylene glycol (EG), Glycerol, and 1,2-PROH were investigated using a murine embryo model. Female $F-{_1}$ mice were stimulated with gonadotropin, induced ovulation with hCG and mated. Two cell embryos were collected and cultured after exposure to among DMSO, EG, Glycerol, and 1,2-PROH. Embryo development was evaluated up to the blastocyst stage. The total cell count of blastocysts that were treated with DMSO and Glycerol at the 2-cell stage was significantly lower than that were treated with EG ($81.1{\pm}15.1$), 1,2-PROH ($88.0{\pm}21.1$) or the control ($99.9{\pm}21.3$) (p<0.001). On comparison of four cryoprotectant treated groups, the DMSO and Glycerol treated group showed a decreased cell count compared with the EG and 1,2-PROH treated group (p<0.05). Both DMSO ($14.7{\pm}1.3$), EG ($12.1{\pm}1.1$), Glycerol ($15.2{\pm}1.8$), and 1,2-PROH ($11.5{\pm}1.3$) treated groups showed higher apoptosis rates of cells in the blastocyst compared with the control ($6.5{\pm}0.7$, p<0.0001). In addition, the DMSO or Glycerol treated group showed more apoptotic cells than the EG or 1,2-PROH treated group (p<0.001). The potential toxicity of cryoprotectants was uncovered by prolonged exposure of murine embryos to among DMSO, EG, Glycerol, and 1,2-PROH at room temperature. When comparing four permeable cryoprotective agents, EG and 1,2-PROH appeared to be less toxic than DMSO and Glycerol at least in a murine embryo model.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.246-246
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• 2013

Atomic layer deposition (ALD)에 의해 증착된 알루미늄 산화막($Al_2O_3$)은 고효율 결정질 실리콘 태양전지를 위한 우수한 패시베이션 효과를 보인다. $Al_2O_3$은 고정 음전하를 가지고 있기때문에 p-형 태양전지 후면에서 field effect passivation에 의한 효과적인 표면 패시베이션을 형성한다. 하지만 ALD에 의한 $Al_2O_3$ 증착은 긴 공정시간이 필요하다. 이는 기존의 태양전지 산업에 적합하지 않다. 본 논문에서는 공정 시간의 단축을 위해 plasma-assisted atomic layer deposition (PA-ALD) 기술을 사용함으로서 $Al_2O_3$을 증착했다. PA-ALD 기술은 trimethyaluminum (TMA)와 plasma 분위기에서의 $O_2$ 가스를 사용하여 표면 반응을 한다. $Al_2O_3$ 층의 특성을 최적화하기 위해 증착 온도를 $150{\sim}250^{\circ}C$의 범위에서 가변하고, 열처리 온도와 시간을 변화하였다. 결과적으로, 실리콘 웨이퍼를 이용하여 $1250^{\circ}C$의 공정온도에서 증착한 $Al_2O_3$은 $400^{\circ}C$에서 10분 동안의 열처리 온도와 시간에서 1,610 ${\mu}s$의 최고의 유효 반송자 수명을 보였다.

• Journal of Chest Surgery
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• v.42 no.1
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• pp.72-78
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• 2009

Background: Mediastinal neurogenic tumors are generally benign lesions and they are ideal candidates for performing resection via video-assisted thoracoscopic surgery (VATS). However, benign neurogenic tumors at the thoracic apex present technical problems for the surgeon because of the limited exposure of the neurovascular structures, and the optimal way to surgically access these tumors is still a matter of debate. This study aims to clarify the feasibility and safety of the VATS approach for performing surgical resection of benign apical neurogenic tumors (ANT). Material and Method: From January 1996 to September 2008, 31 patients with benign ANT (15 males/16 females, mean age: 45 years, range: 8~73), were operated on by various surgical methods: 14 VATS, 10 lateral thoracotomies, 6 cervical or cervicothoracic incisions and 1 median sternotomy. 3 patients had associated von Recklinhausen's disease. The perioperative variables and complications were retrospectively reviewed according to the surgical approaches, and the surgical results of VATS were compared with those of the other invasive surgeries. Result: In the VATS group, the histologic diagnosis was schwannoma in 9 cases, neurofibroma in 4 cases and ganglioneuroma in 1 case, and the median tumor size was 4.3 cm (range: 1.2~7.0 cm). The operation time, amount of chest tube drainage and the postoperative stay in the VATS group were significantly less than that in the other invasive surgical group (p<0.05). No conversion thoracotomy was required. There were 2 cases of Hornor's syndrome and 2 brachial plexus neuropathies in the VATS group; there was 1 case of Honor's syndrome, 1 brachial plexus neuropathy, 1 vocal cord palsy and 2 non-neurologic complications in the invasive surgical group, and all the complications developed postoperatively. The operative method was an independent predictor for postoperative neuropathies in the VATS group (that is, non-enucleation of the tumor) (p=0.029). Conclusion: The VATS approach for treating benign ANT is a less invasive, safe and feasible method. Enucleation of the tumor during the VATS procedure may be an important technique to decrease the postoperative neurological complications.

• Journal of Energy Engineering
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• v.26 no.2
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• pp.73-79
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• 2017

In nucleation assisted crystallization process formed $CO_2$ leaves as colloid gas and is used as the template by the rapidly growing crystals in the nucleation site. This emulsion of $CaCO_3$ micro-crystals & $CO_2$ micro-bubbles forms hollow particles. Formed hollow particles are double walled, both internal and external faces belonging to the cleavage aragonites which separate the surrounding water from the enclosed gas cavity. Hence, the reverse reaction of $CO_2$ with water forming Carbonic Acid is not possible and the pH stability is maintained. In fact every excess $CaCO_3$ crystals are buffering any carbonic acid left over. This $CO_2$ based nucleation technology prevents scale formation in water channels, but it also helps to reduce the previously formed scales. This process takes out water dissolved $CO_2$ in almost-visible micro-bubbles forms that helps reducing previously formed scale over a period of time (depends on the usage period). The aragonite crystals can't form scale because of its stable molecular structure and neutral surface electro potentiality.

• Advances in environmental research
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• v.5 no.1
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• pp.61-77
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• 2016

$NanoTiO_2$ was synthesized by ultrasonication assisted sol-gel process and subjected to iron doping and carbon-iron codoping. The synthesized catalysts were characterized by XRD, HR-SEM, EDX, UV-Vis absorption spectroscopy and BET specific surface area analysis. The average crystallite size of pure $TiO_2$ was in the range of 30 - 33 nm, and that of Fe-$TiO_2$ and C-Fe $TiO_2$ was in the range of 7 - 13 nm respectively. The specific surface area of the iron doped and carbon-iron codoped nanoparticles was around $105m^2/g$ and $91m^2/g$ respectively. The coupled semiconductor photo-Fenton's activity of the synthesized catalysts was evaluated by the degradation of a cationic dye (C.I. Basic blue 9) and an anionic dye (C.I. Acid orange 52) with concurrent investigation on the operating variables such as pH, catalyst dosage, oxidant concentration and initial pollutant concentration. The most efficient C-Fe codoped catalyst was found to effectively destruct synthetic dyes and potentially treat real textile effluent achieving 93.4% of COD removal under minimal solar intensity (35-40 kiloLUX). This reveals the practical applicability of the process for the treatment of real wastewater in both high and low insolation regimes.

• Journal of Chest Surgery
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• v.29 no.10
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• pp.1138-1142
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• 1996

Video-assisted thoracic surgery is a new modality that allows visualization of and access to the intrathoracic organs without making a thoracotomy Incision. 52 patients underwent thoracic procedures using this technique. There were pneumothorax in 40 patients, diffuse interstital lung disease in 6 patients, hyperhidrosis in 3 patients, pulmonary tuberculoma in 1 patient, aspergilloma in 1 patient and localized fibrous tumor of pleura in 1 patient. We had performed a variety of procedures(36 wedge resections with mechanical pleurodesis, 8 wedge resections only, 4 mechanical pleurodeses, 3 bilateral sympathectomys and 1 segmentectomy). The period of chest tube indwelling and postoperative hospitalization were 2.00 $\pm$ 1.32 days(range : 0~6 days) and 3.55 $\pm$ 1.45 days(range : 1~8 days). Four postoperative complications occurred(2 pleural effusion, 1 recurrent pneumothorax and 1 high fever). Conversion to open thoracotomy was done in 1 p tient due to massive air leakage. Patients undergoing video-assisted thoracic surgery seem to have reduced postoperative pain, shorter hospitalization, and quicker recovery times.

• Health Policy and Management
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• v.24 no.2
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• pp.164-171
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• 2014

Background: Safety of drugs has become a major issue in public healthcare. Spontaneous reporting of adverse drug reaction (ADR) is the cornerstone in management of drug safety. We aimed to investigate the awareness and knowledge of spontaneous ADR reporting in general public of Korea. Methods: A total of 1,500 study subjects aged 19-69 years were interviewed with a questionnaire for their awareness and knowledge related to spontaneous ADR reporting. Computer assisted telephone interview was performed from 27th February 2013 to 4th March 2013. Target population was selected with quota sampling, using age, sex, and residence area. Healthcare professionals such as physicians, pharmacists, and nurses were excluded. The survey questions included awareness of spontaneous ADR reporting, opinions on ways to activate ADR reporting, and sociodemographic characteristics. Results: Overall awareness of spontaneous ADR reporting system was 8.3% (${\pm}2.53%$) among general population of Korea. Major source from which people got the information regarding ADR reporting was television/radio (69.9%), followed by internet (19.3%), and poster/brochure (6.1%). Awareness level differed between age groups (p<0.0001) and education levels (p<0.0001). Upon learning about the ADR reporting system, 88.5% of study subjects agreed on the necessity of ADR reporting system, while 46.6% thought promotion through internet and mass media as an effective way to activate ADR reporting. Conclusion: The overall awareness of spontaneous ADR reporting should be enhanced in order to establish a firm national system for drug safety. Adequate promotions should be performed targeting lower awareness groups, as well as various publicity activities via effective channels for the general population.