<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>

In-hospital mortality in patients with STEMI admitted during off hours

( Sung-Soo Kim ),( Myung Ho Jeong ),( Jeong Gwan Cho ),( Young Keun Ahn ),( Jong Hyun Kim ),( Shung Chull Chae ),( Young Jo Kim ),( Seung Ho Hur ),( In Whan Seong ),( Taek Jong Hong ),( Dong-hoon Choi 대한내과학회 2013 대한내과학회 추계학술대회 Vol.2013 No.1

Conflicting results exist on the outcome of off hours PCI in ST elevation myocardial infarction (STEMI). However, there were only a few studies that have focused on the clinical characteristics and outcomes of off hours PCI in STEMI. So, we studied the clinical characteristics and hospital mortality in STEMI patients treated with primary PCI during regular hours (weekdays 9:00 AM to 6:00 PM) versus off hours Weekdays 6:01 PM to 8:59 AM, weekends, and holidays) in Korea Acute Myocardial Infarction Registry. We analyzed in hospital and one year mortality among 5,665 consecutive ST segment elevation myocardial infarction patients treated with primary PCI between November 2005 to January 2008. Total 2,848 (50.2%) patients were treated during off hours. Baseline finding were similar, although regular hours patients were older. Median symptom to balloon time (304 min, IQR 175 to 750 vs. 270 min, IQR 145 to 551, p=0.001) were longer for regular hours primary PCI. Median door to balloon time (71min, IQR: 48 to 132 vs. 59 min, IQR 39 to 110 min, p=0.001) were longer for off hours pPCI. Also, Cardiac enzyme such as Max CK-MB (212.1±299.3 vs 194.7±303.4, p=0.031) and max TnI (72.6±239.5 vs. 58.9±94.4, p=0.013) were increased in off hours pPCI. However, unadjusted in hospital (6.0% off hours vs. 6.0% regular hours, p=0.946) and one year cardiac mortality (11.3% off hours vs. 11.7% regular hours, p=0.661) were comparable. In multivariate analysis, off hours primary PCI did not predict an adverse outcome. In conclusion, when primary PCI was performed within an appropriate reperfusion strategy, the clinical effectiveness of either off hours or regular hours pPCI is comparable.

Temporal trends and in-hospital outcomes of primary percutaneous coronary intervention in nonagenarians with ST-segment elevation myocardial infarction

( Joon Young Kim ),( Myung Ho Jeong ),( Yong Woo Choi ),( Yong Keun Ahn ),( Shung Chull Chae ),( Seung Ho Hur ),( Taek Jong Hong ),( Young Jo Kim ),( In Whan Seong ),( In Ho Chae ),( Myeong Chan Cho ) 대한내과학회 2015 The Korean Journal of Internal Medicine Vol.30 No.6

Background/Aims: Data regarding the outcomes of primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) in nonagenarians are very limited. The aim of the present study was to evaluate the temporal trends and in-hospital outcomes of primary PCI in nonagenarian STEMI patients. Methods: We retrospectively reviewed data from the Korea Acute Myocardial Infarction Registry (KAMIR) from November 2005 to January 2008, and from the Korea Working Group on Myocardial Infarction (KorMI) from February 2008 to May 2010. Results: During this period, the proportion of nonagenarians among STEMI patients more than doubled (0.59% in KAMIR vs. 1.35% in KorMI), and the rate of use of primary PCI also increased (from 62.5% in KAMIR to 81.0% in KorMI). We identified 84 eligible study patients for which the overall in-hospital mortality rate was 21.4% (25.0% in KAMIR vs. 20.3% in KorMI, p = 0.919). Multivariate analysis identified two independent predictors of in-hospital mortality, namely a final Thrombolysis in Myocardial Infarction (TIMI) flow < 3 (odds ratio [OR], 13.7; 95% confidence interval [CI], 3.2 to 59.0; p < 0.001) and cardiogenic shock during hospitalization (OR, 6.7; 95% CI, 1.5 to 30.3; p = 0.013). Conclusions: The number of nonagenarian STEMI patients who have undergone primary PCI has increased. Although a final TIMI flow < 3 and cardiogenic shock are independent predictors of in-hospital mortality, primary PCI can be performed with a high success rate and an acceptable in-hospital mortality rate.

Different Impact of Diabetes Mellitus on In-hospital and 1-Year Mortality in Patients with Acute Myocardial Infarction Who Underwent Successful Percutaneous Coronary Intervention: Results from the Korean Acute Myocardial Infarction Registry

( Keun Ho Park ),( Young Keun Ahn ),( Myung Ho Jeong ),( Shung Chull Chae ),( Seung Ho Hur ),( Young Jo Kim ),( In Whan Seong ),( Jei Keon Chae ),( Taek Jong Hong ),( Myeong Chan Cho ),( Jang Ho Bae ) 대한내과학회 2012 The Korean Journal of Internal Medicine Vol.27 No.2

Background/Aims: The aim of this study was to evaluate the impact of diabetes mellitus (DM) on in-hospital and 1-year mortality in patients who suffered acute myocardial infarction (AMI) and underwent successful percutaneous coronary intervention (PCI). Methods: Among 5,074 consecutive patients from the Korea AMI Registry with successful revascularization between November 2005 and June 2007, 1,412 patients had a history of DM. Results: The DM group had a higher mean age prevalence of history of hypertension, dyslipidemia, ischemic heart disease, high Killip class, and diagnoses as non-ST elevation MI than the non-DM group. Left ventricular ejection fraction (LVEF) and creatinine clearance were lower in the DM group, which also had a significantly higher incidence of in-hospital and 1-year mortality of hospital survivors (4.6% vs. 2.8%, p = 0.002; 5.0% vs. 2.5%, p < 0.001). A multivariate analysis revealed that independent predictors of in-hospital mortality were Killip class IV or III at admission, use of angiotensin converting enzyme inhibitors or angiotensin-II receptor blockers, LVEF, creatinine clearance, and a diagnosis of ST-elevated MI but not DM. However, a multivariate Cox regression analysis showed that DM was an independent predictor of 1-year mortality (hazard ratio, 1.504; 95% confidence interval, 1.032 to 2.191). Conclusions: DM has a higher association with 1-year mortality than in-hospital mortality in patients with AMI who underwent successful PCI. Therefore, even when patients with AMI and DM undergo successful PCI, they may require further intensive treatment and continuous attention.

스티렌 폭로 근로자들의 기중 및 혈중 스티렌과 요중 만델산의 관계 분석

정호근,강성규,양정선,김기웅,이종성,조영숙,박인정 大韓産業醫學會 1994 대한직업환경의학회지 Vol.6 No.1

The concentration of styrene in air in blood and mandelic acid in urine were checked for the 60 workers with normal liver function, exposed to styrene. Styrene in air were sampled with personal air sampler at least 4 hours and analyzed by gas chromatography. Blood and spot urine were collected at the end of shift with a vacuum tube and a polythylene bottle and analyzed by gas chromatography and high performance liquid chromatography. Means of air and blood styrene and urine mandelic acid were 8.16 ppm(geometric mean), 0.199 mg/L, and 0.519 g/g creatinine, respectively. The concentration of styrene in air and mandelic acid in urine were high in the FRP factories and low in polymerization factory. Styrene in blood showed large difference by the working process. Styrene in air showed a good correlation with mandelic acid in urine(r=0.6369) and styrene in blood(r=0.6371). The mandelic acid in urine and styrene in blood corresponded to exposure of 50 ppm styrene were 0.890 g/g creatinine and 0.434 mg/L. However, hippuric acid in urine did not show any correlation with styrene in air. Urine mandelic acid excretion expected ratio showed a tendency to decrease according to obesity index and to increase with alcohol consumption.

Decreased Glomerular Filtration Rate is an Independent Predictor of In-Hospital Mortality in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Kim, Joon Young,Jeong, Myung Ho,Ahn, Yong Keun,Moon, Jae Hyun,Chae, Shung Chull,Hur, Seung Ho,Hong, Taek Jong,Kim, Young Jo,Seong, In Whan,Chae, In Ho,Cho, Myeong Chan,Kim, Chong Jin,Jang, Yang Soo,Yo The Korean Society of Cardiology 2011 Korean Circulation Journal Vol.41 No.4

<P><B>Background and Objectives</B></P><P>Patients with renal dysfunction (RD) experience worse prognosis after myocardial infarction (MI). The aim of the present study was to investigate the impact of admission estimated glomerular filtration rate (eGFR) on clinical outcomes of patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation MI (STEMI).</P><P><B>Subjects and Methods</B></P><P>We retrospectively evaluated 4,542 eligible patients from the Korea Acute Myocardial Infarction Registry (KAMIR). Patients were divided into three groups according to eGFR (mL/min/1.73 m<SUP>2</SUP>): normal renal function (RF) group (eGFR ≥60, n=3,515), moderate RD group (eGFR between 30 to 59, n=894) and severe RD group (eGFR <30, n=133). Baseline characteristics, angiographic and procedural results, and in-hospital outcomes between the three groups were compared.</P><P><B>Results</B></P><P>Age, gender, Killip class ≥3, hypertension, diabetes, congestive heart failure, peak creatine kinase-MB, high sensitivity C-reactive protein, B-type natriuretic peptide, left ventricle ejection fraction, multivessel disease, infarct-related artery and rate of successful PCI were significantly different between the 3 groups (p<0.05). With decline in RF, in-hospital complications developed with an increasing frequency (14.1% vs. 31.8% vs. 45.5%, p<0.0001). In-hospital mortality rate was significantly higher in the moderate and severe RD groups as compared to the normal RF group (2.3% vs. 13.9% vs. 25.6%, p<0.0001). Using multivariate logistic regression analysis, adjusted odds ratio for in-hospital mortality was 2.67 {95% confidence interval (CI) 1.44-4.93, p=0.002} in the moderate RD group, and 4.09 (95% CI 1.48-11.28, p=0.006) in the severe RD group as compared to the normal RF group.</P><P><B>Conclusion</B></P><P>Decreased admission eGFR was associated with worse clinical courses and it was an independent predictor of in-hospital mortality in STEMI patients undergoing primary PCI.</P>

내원시 저혈당이 당뇨병을 동반한 심근경색증 환자의 예후에 미치는 영향

김은정 ( Eun Jung Kim ),정명호 ( Myung Ho Jeong ),정인석 ( In Seok Jeong ),오상기 ( Sang Gi Oh ),김상형 ( Sang Hyung Kim ),안영근 ( Young Keun Ahn ),김주한 ( Ju Han Kim ),김영조 ( Young Jo Kim ),채성철 ( Shung Chull Chae ),홍택종 대한내과학회 2014 대한내과학회지 Vol.87 No.5

목적: 당뇨병 환자에게 철저한 혈당 조절은 논란의 여지가 있으며, 이에 당뇨병을 동반한 급성 심근경색증 환자의 내원 시 저혈당과 병원 내 주요 임상 사건 및 사망률 그리고 추적관찰 1년간 사망률과의 관계를 알아보고자 하였다. 방법: 2005년 11월부터 2012년 3월까지 KAMIR에 등록된 당뇨병이 동반된 급성 심근경색증 환자 5,249명을 혈당 수치에 따라서 저혈당을 보인 환자(≤ 70 mg/dL)를 I군(93명, 72.6± 11.0세, 여성 46.2%), 정상혈당을 보인 환자(> 70 and < 140)를 II군(1,262명, 71.3 ± 10.7, 여성 34.3%), 고혈당을 보인 환자(≥ 140)를 III군(3,894명, 70.3 ± 11.1, 여성 36.0%)으로 분류하여, 병원 내 주요 임상사건 및 1년 후 사망률과의 관계를 비교하였다. 결과: 각 군의 평균 연령은 I군(72.6 ± 11.0세), II군(71.3 ±10.7세), III군(70.3 ± 11.1세)으로 I군에서 연령이 높았다(p =0.006). I군에서 내원 시 비전형적인 증상 양상(p = 0.002), Killip class III-IV (p = 0.003), 심초음파을 이용한 좌심실 구혈률 40% 미만의 환자(p = 0.002), NSTEMI가 많았다(p = 0.001). 전체 대상 환자 5,249명 중 344명(6.6%)이 입원 중 사망하였으며, 이 중에서 I군 12명(12.9%), II군 66명(5.2%), III군 266명(6.8%)으로 I군에서 사망률이 유의하게 높았다(p = 0.006).다변량 회귀분석에서 나이(p = 0.001), Killip class III-IV (p =0.001), 뇌혈관 질환(p = 0.002), 만성 신부전증(p = 0.001), 급성 신부전증(p = 0.001), 심인성 쇼크(p = 0.001), 심실성 빈맥증(p = 0.005), 좌심실 구혈률 40% 미만(p = 0.001), 내원시 혈당 70 mg/dL 미만(p = 0.005)은 추적관찰 한 달간 사망률에 독립적인 예측인자이었다. 정상 혈당군에 비하여 저혈당 군에서 사망률이 유의하게 증가하였고(OR 3.571, 95% CI1.465-8.705, p = 0.005). 고혈당군에 비해 저혈당군에서 사망률이 유의하게 증가하였다(OR 4.088, 95% CI 1.757-9.511, p= 0.001). 그러나 추적관찰 1년간에서 내원시 혈당은 사망률의 유의한 예측인자가 아니었다(p = 0.428). 결론: 당뇨병을 동반한 심근경색증 환자의 내원 시 저혈당은 입원중과 추적관찰 한 달간의 사망률을 예측할 수 있는 예후인자였다. Methods: We analyzed 5,249 diabetic patients who enrolled in the Korean Acute Myocardial Infarction Registry from November 2005 to March 2013. The patients were divided into three groups according to their blood glucose level at admission; Group I:hypoglycemia (≤ 70 mg/dL), Group II: normoglycemia (70-140 mg/dL) and Group III: hyperglycemia (≥ 140 mg/dL). We assessed in-hospital mortality and the major adverse cardiac events based on blood glucose levels at admission. Results: The mean age was older in group I at 72.6 ± 11.0 years compared to 71.3 ± 10.7 in group II and 70.3 ± 11.1 in group III (p < 0.006). A total of 344 patients died during hospitalization. In-hospital mortality was higher in group I at 12.9%, compared to 5.2% in group II and 6.8% in group III (p < 0.006). Multivariable logistic regression analysis determined that the independent predictors of 1-month mortality were age, Killip class III-IV, cerebrovascular disease, chronic renal failure, acute renal failure, cardiogenic shock, ventricular tachycardia, ejection fraction < 40% and hypoglycemia in admission. The mortality rate at 1 month was significantly higher in group I compared to group II (odds ratio [OR] 3.571; 95% confidence interval [CI] 1.465-8.705, p = 0.005) compared to group II and group III (OR 4.088; 95% CI 1.757-9.511, p = 0.001). Conclusions: Hypoglycemia on admission was an important predictor of in-hospital and one-month mortality in AMI patients with diabetes mellitus. (Korean J Med 2014;87:565-573)

절제된 정상위벽의 자기공명영상기법에 관한 연구:조직소견과의 비교

서보경,설혜영,이남준,차인호,정규병,김정혁,박철민,이지영,Seo, Bo-Gyeong,Seol, Hye-Yeong,Lee, Nam-Jun,Cha, In-Ho,Jeong, Gyu-Byeong,Kim, Jeong-Hyeok,Park, Cheol-Min,Lee, Ji-Yeong 대한영상의학회 2001 대한영상의학회지 Vol.45 No.5

목적:급속자기공명영상기법을 이용하여 절제된 정상위벽을 관찰하고,이를 조직소견과 비교 연구하여,위벽의 관찰을 위한 최적기법을 찾고자 하였다. 대상과 방법:25명 환자의 모두 41개 절제된 정상위조직을 수술후 수지(polyethylene)통에 넣고,생리식염수로 채워 자기공명영상을 시행하였다.T1강조FLASH,지방억제T1강조FLASH, T2강조TSE와 True-FISP 등 4가지 기법으로 위조직의 영상을 얻었다.자기공명영상에서는 위벽의 층수와 각층의 신호강도를 관찰하였고,이를 조직소견과 비교하였다.자기공명영상소견을 조직소견과 비교한 후 위벽 각층의 명확성과 각층간의 구분,및 전체 영상의 질에 대하여 비교하였다.4가지 기법 중 가장 좋은 방법은 3,가장 나쁜 방법은 0으로 하여 등급을 판정하였다. 결과:자기공명영상에서 위벽의 층수는 T1강조FLASH에서 2층이 41예 중 6예(14.6%),3층 31예(75.6%),및 4층 4예(9.8%)였고,지방억제T1강조FLASH에서 2층 6예(14.6%)와 3층 35예(85.4%),T2강조TSE에서 3층 24예(58.5%),4층 11예(26.8%),및 5층 6예(14.6%)였으며,True-FISP에서 1층 2예(4.9%),2층 8예(19.5%),3층 23예(56.0%),4층은 4예(9.8%), 및 5층 4예(9.8%)이었다.위벽의 신호강도는 T1강조FLASH와 지방억제T1강조FLASH에서 2층으로 보인 예는 위내강으로부터 고-중등도,3층인 경우는 고-저-고/중등도,4층인 예는 고-저-고-중등도신호강도였다.T2강조TSE에서는 3층으로 보인 예는 등도/고-저-중등도,4 층인 경우는 중등도-저-고-중등도/저,5층인 예는 저-고-저-고-저신호강도였다.자기공명 영상소견을 조직소견과 비교하였을 때 위벽이 3층으로 보인 경우 이것은 “점막층-점막하층-근층 ”에 해당하였다.관찰한 3가지 면 모두에서 T1강조FLASH,지방억제T1강조FLASH,T2강조TSE 기법이 True-FISP보다 통계적으로 유의하게 우수하였다(p=0.001).점막층의 명확성에 있어서 가장 우수한 기법은 T1강조FLASH와 지방억제T1강조FLASH이었고(p<0.05),점막하층의 명확성과 점막하층과 근층간의 구분은 T2강조TSE가 가장 우수하였다(p<0.05).전체적인 영상의 질은 T1강조FLASH와 T2강조TSE에서 가장 우수하였다(p<0.05). 결론:자기공명영상은 위벽의 각 층을 구별할 수 있는 우수한 검사로 조직소견과 높은 연관성을 보이며,전체 영상의 질,점막하층의 명확성 및 점막하층과 근층간의 구분이 T2강조TSE에서 가장 우수한다. Purpose: To evaluate normal human gastric wall layers in vitro using magnetic resonance*(MR) imaging, to correlate the results with the histologic findings, and to determine the optimal technique for evaluation of the gastric wall. Materials and Methods: Forty-one normal resected gastric specimens obtained from 25 patients were dissected and placed in a polyethylene tube filled with normal saline. MR imaging with four MR sequences, T1-weighted FLASH*(T1FLASH), fat-saturated T1-weighted FLASH, T2-weighted TSE*(T2TSE), and True-FISP, was performed. The number of gastric wall layers and signal intensity of each layer were determined, and after correlating MR images with the histologic findings, the conspicuity of each layer*(mucosa, submucosa, and muscle), the distinction between each layer, and overall image quality were assessed. results: The gastric wall was shown by TIFLASH to have two (n=6, 14-6%), three (n=31, 75.6%) and four layers (n=4, 9.8%); by fat-saturated TIFLASH to have two (n=6, 14.6%) and three (n=35, 85.4%) ; by T2TSE to have three (n=24, 58.5%), four (n=11, 26.8%), and five (n=6, 14.6%); and by True-FISP to have one (n=2, 4.9%), two (n=8, 19.5%), three (n=23, 56%), four (n=4, 9.8%), and five (n=4, 9.8%) . The signal intensity of each layer at T1FLASH and fat-saturated T1FLASH was high-intermediate from the lumen in two-layer cases, high-low-high/intermediate in three-layer cases, and high-low-high-intermediate in four-layer cases. The signal intensity of each layer at T2TSE was intermediate/high-low-intermediate in three-layer cases, intermediatelow-high-intermediate/low in four-layer cases, and low-high-low-high-low in five-layer cases. Three-layered gastric wall corresponded mostly to mucosa, submucosa, and muscle from the inner to outer layers, respectively. T1FLASH, fat-saturated T1FLASH, and T2TSE were superior to True-FISP in evaluating the gastric wall. T1FLASH and fat-saturated T1FLASH were the best sequences for demonstrating mucosa (p<0.05), and T2TSE was the best for submucosa and the distinction between this and muscle (p<0.05). Both T1FLASH and T2TSE provided the best overall image quality (p<0.05). Conclusion: In-vitro MR imaging is an excellent technique for the evaluation of layers of normal gastric wall. T2TSE is the sequence which best demonstrates the conspicuity of submucosa, the distinction between submucosa and muscle, and overall image quality.

상이한 악궁처치방법에 따라 채득한 인상체의 보철학적 평가

정우인,조인호 단국대학교 치의학연구소 1996 논문집 Vol.8 No.1

The antagonisitic cast must accurately reproduce the occlusal morphologic features to simulate the actual clinical occlusoarticular situation in the articulator. Various preimpression preparation procedures have been used for obtaining the accurate quality of occlusal reproduction in taking irreversible hydrocolloid impressions. This study evaluated and determined how different procedures for preimpression preparation of the oral cavity influence the quality of the occlusal reproduction of teeth on the casts. In this study, bubble counts on the casts according to preimpression preparation or alginate types (normal set and fast set) were compared and analyzed. The results were as follows; 1. The bubble count on casts was increased in GroupⅠ, GroupⅢ, GroupⅣ and GroupⅡ, GroupⅤ in that order, and the quality of occlusal reproduction according to preimpression procedures showed GroupⅠ to be excellent. There was no significant difference between bubble counts according to alginate types. 2. There was significantly difference between bubble counts according to preimpression procedures in each of three bubble sizes(p<0.05). GroupⅠ in case of Type Ⅰ and Type Ⅱ bubbles, GroupⅠ and Group Ⅲ in the case of Type Ⅲ bubbles showed the lowest bubble count with stastically significant difference(p<0.05). 3. There was no significant difference between bubble counts according to alginate types in each of three bubble sizes(p>0.05). According to the results of this study, it was considered that the quality of occlusal reproduction was the most excellent when fluid hydrocolloid was finger -painted onto the occlusal surfaces in taking hydrocolloid impressions after the oral cavity and occlusal surfaces were dried by a vacuum suction and jet of air.

Power Generation Using Magnetic Nanofluids in Millimeter-Sized Channel With In-Phase Mode of Magnetization

In-Ho Kim,Jong-Chul Lee,Sangyoup Lee,Geun-Young Jeong,Se-Hee Lee IEEE 2015 IEEE transactions on magnetics Vol.51 No.11

<P>Magnetic nanofluids (MNFs) are an interesting energy harvesting source. In this paper, the flow energy harvesting was experimentally and numerically investigated in a millimeter-sized channel using an externally applied permanent magnet to control the magnetizing direction of the magnetic nanoparticles (MNPs). Oil- or water-based MNF includes a certain percentage of magnetized nanoparticles and has unique features that vary with the strength of the external electromagnetic field. When the MNF flows through a cross-sectional area of the coil loop, the electromotive force can be obtained by following Faraday's law, because the MNPs act as permanent magnets. When the MNFs are used for flow energy harvesting, the main issue is the in-phase mode alignment of the MNPs magnetization with the coil loop. Without the in-phase mode, the electric power cannot be generated, because the net magnetization of the MNF is zero. Most of the previous research works, however, have not considered it. Thus, to implement this mode, we proposed an externally applied magnetic field generated by a cylindrically shaped permanent magnet. Short and closed Teflon tubing with a 1.5 mm inner diameter, containing the MNF, was located inside long silicon tubing and moved along the positive and negative directions by a pump. Then, the generated voltages were measured, and exhibited similar results to those obtained analytically. In the same way, we calculated and experimentally tested a chain type of Teflon tubing.</P>