<i>In vitro</i> and <i>in vivo</i> evaluation of a novel polymer-free everolimus-eluting stent by nitrogen-doped titanium dioxide film deposition

Park, Dae Sung,Bae, In-Ho,Jeong, Myung Ho,Lim, Kyung Seob,Sim, Doo Sun,Hong, Young Joon,Lee, So-Youn,Jang, Eun Jae,Shim, Jae-Won,Park, Jun-Kyu,Lim, Han Chul,Kim, Han Byul Elsevier 2018 Materials Science and Engineering C Vol.91 No.-

<P><B>Abstract</B></P> <P>Inflammation and thrombosis are linked to the use of polymer-based drug-eluting stents (DES). The aim of this study was to develop a polymer-free everolimus (EVL)-eluting stent using nitrogen-doped titanium dioxide (N-TiO<SUB>2</SUB>) and verify its efficacy by <I>in vitro</I> and <I>in vivo</I> assessment in a porcine coronary model. Various analytical approaches such as scanning electron microscopy and atomic force microscopy, electron spectroscopy, Fourier transform infrared spectrometry and contact angle measurement were employed for the characterization. As a part of biocompatibility assessment, platelet adhesion and smooth muscle cell (SMC) proliferation were examined. Bare metal stent (BMS), N-TiO<SUB>2</SUB> stent, everolimus-eluting N-TiO<SUB>2</SUB> (N-TiO<SUB>2</SUB>-EVL) stent, and commercialized EVL-eluting stent (EES) were randomly placed in forty coronary arteries in twenty pigs. After four weeks of implantation, the stents were subjected to histological and quantitative analysis. The N-TiO<SUB>2</SUB> film used in this study was well coated without any cracks or peeling. Surface hydrophilicity (88.8% of angle decrement) could be associated with the decrease in surface roughness post N-TiO<SUB>2</SUB> deposition (37.0%). The platelet adhesion on the N-TiO<SUB>2</SUB> surfaces was less than that on the BMS surface. The proliferation of SMC was suppressed in the N-TiO<SUB>2</SUB>-EVL group (30.2%) but not in the BMS group. In the animal study, the percent area restenosis was significantly decreased in the N-TiO<SUB>2</SUB>-EVL group compared to that in the BMS group. The results (BMS; 47.0 ± 11.00%, N-TiO<SUB>2</SUB>-EVL; 31.7 ± 10.50%, and EES; 29.1 ± 11.21%, <I>n</I> = 10, <I>p</I> < 0.05) were almost at par with those of the commercialized EVL-eluting stent. The introduction of N-TiO<SUB>2</SUB> deposition during fabrication of polymer-free DES may be an efficient accessorial process for preventing in-stent restenosis and thrombosis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N-TiO<SUB>2</SUB> surfaces can help to reduce the platelet adhesion. </LI> <LI> In porcine model, N-TiO<SUB>2</SUB> everolimus decreased in-stent restenosis and fibrin deposition. </LI> </UL> </P>

Transfer of ultrathin molybdenum disulfide and transparent nanomesh electrode onto silicon for efficient heterojunction solar cells

Kang, Sung Bun,Kwon, Ki Chang,Choi, Kyoung Soon,Lee, Rochelle,Hong, Kootak,Suh, Jun Min,Im, Min Ji,Sanger, Amit,Choi, In Young,Kim, Soo Young,Shin, Jae Cheol,Jang, Ho Won,Choi, Kyoung Jin Elsevier 2018 Nano energy Vol.50 No.-

<P><B>Abstract</B></P> <P>Two-dimensional transition-metal dichalcogenides (TMDCs) are very promising for photovoltaic (PV) applications due to their excellent light absorption properties and appropriate bandgap energy, Although multifunctional applications of TMDCs in photovoltaic devices have been achieved, the photovoltaic conversion efficiency under 1 sun is still very low with small active area because of their inexpedient high sheet resistance and limitation of synthesis techniques. In this study, we demonstrate uniform synthesis of 4-in. wafer-scale MoS<SUB>2</SUB> thin films by thermal decomposition of solution precursors. The solar cells are fabricated by transferring n-MoS<SUB>2</SUB> thin films on p-Si substrates to form p-n heterojunctions and then transferring Au nanomeshes prepared in a novel surface treatment as transparent top electrodes onto MoS<SUB>2</SUB>. The circular n-MoS<SUB>2</SUB>/p-Si heterojunction solar cell exhibited a power conversion efficiency of 5.96% at a diameter of 0.3 in. and proved to be easily scalable to 1-in. diameter with 5.18% efficiency. To the best of our knowledge, the solar cells of this study are the most efficient and the largest in all types of solar cells based on TMDC reported so far. Finally, based on finite difference time-domain simulation, we proposed a strategy for implementing n-MoS<SUB>2</SUB>/p-Si heterojunction solar cell with efficiency higher than 15% by introducing optimal doping control of n-MoS<SUB>2</SUB> and efficient anti-reflection layers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The large scale, uniform (4-in.) MoS<SUB>2</SUB> thin films are synthesized. </LI> <LI> High transparent, low sheet resistances electrodes are fabricated in a novel way. </LI> <LI> The efficient MoS<SUB>2</SUB> based solar cells are developed by all transfer process including top electrodes. </LI> <LI> The highest, largest MoS<SUB>2</SUB> p-Si/ heterojunction solar cells are demonstrated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P> <B>The highest performance (5.96%), largest area (1 in.) n-MoS2/p-Si solar cells with transparent electrodes fabricated by a novel way.</B> The transparent electrodes lowers the series resistance of the fabricated solar cells, facilitating the collection of photo-generated carriers from the junction. In our knowledge, we have achieved the highest photovoltaic performance at largest active area by using transparent nanomesh electrode among TMDC based solar cells.</P> <P>[DISPLAY OMISSION]</P>

공군사관생도의 심폐능력에 따른 심리 · 생리요인 비교

김인기(In-ki Kim),김건희(Gun-hee Kim),송성우(Sung-woo Song),최가람(Ga-ram Choi),엄장원(Jang-won Eom),곽재준(Jae-jun Kwak),유영남(Young-nam You),정덕화(Deok-hwa Jeong),강지훈(Ji-hun Kang) 육군사관학교 화랑대연구소 2019 한국군사학논집 Vol.75 No.2

The purpose of this study was to analyze the differences in psychological and physiological factors between groups by classifying groups based on the 3km running record of fourth grade Air Force Academy cadets. Among the top 46 Air Force Academy cadets who wanted to participate in the study, the study conducted an open survey of the top 13 and the bottom 15 who wanted to provide the data prior to the study. The subjects of the experiment and in-depth interview were studied by a total of 18 people, 9 of each upper and lower members who wished to participate in the study. Psychological factors were structured through inductive content analysis of data extracted from in-depth interviews, and physiological factors were conducted to verify differences between groups of body composition and cardiopulmonary function. The psychological factors of the upper and lower groups were found to be general areas of performance strategy, achievement motivation, emotional response, military spirit, situation perception, and basic physical strength. In the detailed areas, the subjects were also examined in 15 areas including physical fitness indicators, confidence, condition control, task orientation, and positive self-perception. As a result of comparison between upper and lower groups, the upper group was 2.2 times higher than the lower group and the lower group was 1.7 times higher than the upper group in the military spirit and performance strategy of the general area response rate. In general area response, the ratio of mental strength and confidence was different in the general area of military spirit. In addition, the upper group in the achievement motivation showed a high percentage of task tendency at 47%, while the lower group showed a high rate of zero motivation at 50%. In the emotional response, the upper group showed an equal ratio, while the lower group showed an 81% ratio of negative emotions. In the overall response by sub-region, the negative emotions of the subgroup were high at 28%. In the body composition, BFM showed a statistically significant difference between upper and lower groups, and Weight, FFM, and SMM did not show any significant difference between groups. In cardiopulmonary capacity, VO2max showed a statistically significant difference between upper and lower groups, and VE and LT did not show significant differences between groups.

GR-tree: 무선 센서 네트워크에서 에너지 효율적인 분산 공간색인기법

김민수,장인성,Kim, Min-Soo,Jang, In-Sung 한국공간정보학회 2011 한국공간정보학회지 Vol.19 No.5

최근 특정 공간영역 내에 포함되는 센서노드들만의 센싱정보를 에너지 효율적으로 수집하는 센서 네트워크 기반 공간질의처리에 대한 관심이 증가하고 있다. 이러한 센서 네트워크 기반 공간질의처리의 가장 단순한 방법은 모든 센서노드의 위치와 센싱정보를 서버로 수집한 다음, 서버에서 공간질의를 처리하는 Centralized 방법이다. 이 방법은 간단하다는 장점은 있지만, 모든 센서노드를 접근하기 위하여 소요되는 높은 무선통신 비용으로 인하여 센서노드의 에너지 효율성이 크게 떨어지는 단점을 가지고 있다. 이러한 Centralized 방법을 보완하기 위하여 센서노드에서 분산 공간 필터링을 수행하여 센서노드 간의 무선통신 횟수를 감소시키는 In-network 기반 분산 공간색인기법들이 제안되어 왔다. 그러나, 이러한 분산 공간색인기법들은 대부분 서버에서 이용되던 기존 공간색인기법들을 센서 네트워크에 단순히 적용하였기 때문에, In-network 환경에서 공간 필터링의 효과와 센서노드들 간의 무선 라우팅을 동시에 최적화하지 못하는 단점을 가지고 있다. 이에 본 논문에서는 In-network 환경에서 공간 필터링을 최적화하면서 동시에 센서노드들 간의 라우팅을 보장할 수 있는 GR-tree의 새로운 분산 공간색인기법을 제안하고자 한다. GR-tree 방법은 R-tree와 유사하게 MBR 기반의 트리를 구성하며, 센서노드들 간의 무선 라우팅 및 공간적인 인접성을 보장하면서 MBR들 간의 겹침을 최소화할 수 있는 특징을 가지고 있다. 끝으로, GR-tree와 기존 방법들의 다양한 성능 비교 실험을 통하여 제안된 방법의 효율성을 보여주고자 한다. Recently, there has been much interest in the spatial query which energy-efficiently acquires sensor readings from sensor nodes inside specified geographical area of interests. The centralized approach which performs the spatial query at a server after acquiring all sensor readings, though simple, it incurs high wireless transmission cost in accessing all sensor nodes. In order to remove the high wireless transmission cost, various in-network spatial indexing schemes have been proposed. They have focused on reducing the transmission cost by performing distributed spatial filtering on sensor nodes. However, these in-network spatial indexing schemes have a problem which cannot optimize both the spatial filtering and the wireless routing among sensor nodes, because these schemes have been developed by simply applying the existing spatial indexing schemes into the in-network environment. Therefore, we propose a new distributed spatial indexing scheme of the GR-tree. The GR-tree which form s a MBR-based tree structure, can reduce the wireless transmission cost by optimizing both the efficient spatial filtering and the wireless routing. Finally, we compare the existing spatial indexing scheme through extensive experiments and clarify our approach's distinguished features.

Evaluation of ion implantation for anti-thrombogenic coronary stent in vitro and in vivo

Shim, Jae-Won,Bae, In-Ho,Park, Dae Sung,Lim, Kyung-Seob,Lee, So-Youn,Jang, Eun-Jae,Park, Jun-Kyu,Kim, Ju Han,Jeong, Myung Ho Elsevier 2017 Journal of industrial and engineering chemistry Vol.54 No.-

<P><B>Abstract</B></P> <P>The aim of this study was to evaluate the effect of ion implantation on the surface of anti-thrombogenic coronary stent. Nitrogen (N) was implanted into the cobalt–chromium surface by using an ion source under a plasma environment to enhance its hardness and surface modification. The N ion dosage was 1×10<SUP>15</SUP> ions/cm<SUP>2</SUP>. All analysis results of the ion implanted stent were compared with those of bare metal stent. The N component and distribution were confirmed by auger electron spectroscopy. Microhardness was significantly increased after 40min of implantation (415.3±12.38 HV, 18.9±2.62%). The surface was altered to hydrophobic status through ion implantation (30.6±1.12% in contact angle increment). Platelet adhesion, and smooth muscle cell migration and proliferation were prevented in the ion implanted group (43.9%, 11.2%, and 45.1%, respectively). To verify the in vitro result, stents were implanted to rabbit iliac artery and isolated at 4 weeks post implantation. Then, the stents were subjected to histological analysis. No significant differences in injury score, internal elastic lamina, lumen area, and restenosis rate were found. However, the fibrin score was more significantly decreased in the ion beam-implanted group (2.5±0.15) than in the bare metal stent group (1.8±0.31, <I>n</I> =10, <I>p</I> <I><</I> 0.05). Taken together, ion beam implantation may be an efficient accessorial tool for preventing in-stent restenosis and in-stent thrombosis.</P>

스키 리조트 이용자의 여가갈등에 관한 연구

한우진(Woo Jin Han),이장희(Jang Hee Lee),여인성(In Sung Yeo) 한국여가레크리에이션학회 2005 한국여가레크리에이션학회지 Vol.29 No.-

Although various studies concerning leisure conflict have been conducted in the U.S, there is little research in this area for Korean. There are many both unasked and unanswered questions in the experience of leisure conflict between or among various leisure activity group. Therefore, an attempt to understand the experience of leisure conflict in ski resort between skier and snowboarder may provide new insights into the nature of leisure conflict of Korean. The purpose of this study was to examine differences of leisure conflict by demographic variables and investigated effect of user’s characteristics in leisure conflict between skier and snowboarder.For this study, 482 participants were selected from 2 ski resorts located in Kangwon Province for one month from January 15th to February 15, 2005, using the convenience sampling method. For the data analysis SPSS 12.0 for Windows version was utilized. The hypothesis tests were conducted with independent t-test, one-way ANOVA, and Multiple Linear Regression to solve problems of the study. On the basis of the results, the conclusions were drawn as follows; 1. There are differences in leisure conflict between or among skier and snowboarder’ demographic characteristics(gender and age group) 2. Leisure conflicts of skier are effected by user’s background in both in-group and out-group. 3. Leisure conflicts of snowboarder are effected by user’s background in both in-group and out-group.

지오텍스타일 튜브를 활용한 준설오니 탈수처리 방안에 대한 현장 시험연구

신은철(Shin Eun-Chul),김성환(Kim Sung-Hwan),장우람(Jang Woo Lam),오영인(Oh Young-In) 한국토목섬유학회 2008 한국토목섬유학회 학술발표회 Vol.2008 No.4

Recently, the dewatering technology by geosynthetics for high water content materials has many applications in variety fields such as PVDs, EKG(Electorkinetic geosynthetic, and getoextile tube and container technology. Especially, the geotextile tube technology for dwatering is sellf -weight consolidation process after pour sludge by filtering and dewatering functions. In this paper, to examine the dewatering capacity and fileld effectiveness of geotextile tube, the field test was performed. Based on the field test results, the suitable mixing ratio of water and filling material is about 6:4 at least. Also, the polypropylene geotextile is more effective for drainage and dewatering function of geotextile tube technology.

In-situ Test of ZigBEE System for Wireless Vibration Monitoring

Seo Il Chang(장서일),HyeSung Jeon(전혜성),In Jang Hwang(황인장),Sung-Hwan Jung(정성환) 한국소음진동공학회 2016 한국소음진동공학회 학술대회논문집 Vol.2016 No.10

32-bit 임베디드 시스템을 이용한 자동변속기용 전자제어시스템의 Software-in-the-loop simulation

장인규(In-Gyu Jang),서인근(Inkeun Seo),전재욱(Jaewook Jeon),황성호(Sung-Ho Hwang) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Drivers are becoming more fatigued and uncomfortable as traffic densities increase, which can lead to slower reaction time, They then face the danger of traffic accidents due to an inability to cope with frequent shifting, To reduce this risk some drivers prefer automatic transmissions (AT) to manual transmissions (MT), The AT is superior drivability and less shifting shock than the MT, so the market-share of AT is increasing, The AT is controlled by Electronic Control Unit (ECU) to obtain better shifting performance, The Transmission Control Unit (TCU) is a product of higher-value-added, so the companies which have advanced technology (BOSCH, SIEMENS VDO, DELPHI, and etc.) tend to evade technology transfer. As the number of ECU used on a car is increasing gradually (for example, engine management unit, transmission control unit, brake control unit, and powertrain control unit), TCU's performance is expected to be faster and more efficient for organic communication and arithmetic processing between the control systems than the performance of 16bit controller. In this paper, the model of automatic transmission vehicle using MATLAB/Simulink is developed for the hardware in-the-loop simulation with an embedded system. The AT control logic developed is loaded to 32-bit Embedded system platform developed on the basis of Freescale's MPC565, and we execute the Software-in-the-loop simulation (SILS) of AT based on Real Time Operating System (RTOS). These test results show that the developed embedded system can be used as AT control unit.

솔라셀을 이용한 그린하우스용 도난 경보 및 자동 온도 유지 관리 시스템

이정일(Jung-Il lee),윤석암(Suk-Am Yoon),윤형상(Hyung-Sang Yoon),최장균(Jang-Gyun Choi),정학수(Hak-Su Jung),윤용선(Yong-Sun Yoon),차인수(In-Su Cha) 전력전자학회 1999 전력전자학술대회 논문집 Vol.- No.-

In this paper, we transformed photovoltaic energy to electric energy using solar cells for drive power source and charged 1t with batteries. This system was programmed in a one-chip microprocessor PIC. This system can be available for the greenhouses set at countrysides and suburbs because it keeps the temperature ins1de constant and can also be used as a protection against burglars at the harvesting season. This alarm system detects the intrusion or the variation of rap1d temperature inside of the greenhouse and warns an alarm and turn on and off the siren