Thermal Expansion Behavior of Thermally Expandable Microspheres Prepared by Suspension Polymerization Using P(AN-MMA-MAA) Core/Shell

Hyun Tae Kim,Ashok Kumar Jaladi,Yong Jin Lee,Duk Keun An 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.2

Thermally expandable microspheres (TEMs) have widespread industrial applications. In this study, high heat resistant and largely expandable TEMs have been synthesized by suspension polymerization. Microspheres were prepared with acrylonitrile (AN) as the main monomer. Initial thermomechanical analysis of TEMs containing AN and methyl acrylate (MA) showed good thermal expansion, leading to the investigation of the polymerization using various monomers at variable weight ratios. TEMs with co-polymer AN, methyl methacrylate (MMA), and methacrylic acid (MAA) were investigated for the first time. They displayed wider heating range and larger expansion rate than the microspheres with MA monomer. The effect of varying amounts of monomer ratios on the thermal expansion behavior is discussed.

杜仲과 木瓜의 混合 煎湯液이 흰쥐의 卵巢摘出로 유발한 骨多孔症에 미치는 影響

李鍾安,盧昇鉉,安德均,崔湖榮 대한본초학회 2001 大韓本草學會誌 Vol.16 No.1

The purpose of this study is to examine the effects of Eucommiae Cortex and Chaenomelis Fructus on the aged ovariectomized rat, similar model with postmenopausal osteoporosis. The results of the experiment are as follows, 1. The body weight in OVX/ECCF group showed a increase.. 2. The level of S-AST and S-ALT in OVX/ECCF group significantly reduced. 3. Urinary volume and creatinine in OVX/ECCF group reduced.. The level of urinary deoxypyridinoline in OVX/ECCF group fignificantly reduced. According to the above results, this experiment indicates that OVX/ECCF group stimulated born formation and diminished the loss of born marrow, then recovered the failure of liver function on ovariectomized rat. In conclusion, an extract of Eucommiae Cortex and Chaenomelis Fructus showed preventive and curing effects in treating osteoporosis of ovariectomized rats. This result suggests that it can be used in preventing senile and postmenopausal osteoporosis. As for its effects, continuous clinical study is needed.

Comparison of EMG Activity during Trunk Forward Bending with and without Limited Lumbar Flexion Angle

Soo-Hyun Bae(Soo-Hyun Bae),Duk-Hyun An(Duk-Hyun An),Jae-Seop Oh(Jae-Seop Oh),Won-Gyu Yoo(Won-Gyu Yoo) 한국임상움직임치료학회 2022 한국임상움직임치료학회지 Vol.2 No.1

Background: Several studies have evaluated the relationship of low back pain with lumbar flexion angle and muscle activity. However, there are scant studies on the relationship between the ratio of normalized muscle activities and lumbar flexion angle. The lumbar flexion angle has been used to diagnose low back pain and to determine the predominantly used muscles during trunk forward bending in asymptomatic individuals. Prolonged sitting is associated with a slumped or upright sitting posture, which can affect the soft tissues in the lumbar region. Objectives: The purpose of this study was to determine the predominantly used muscles during forward bending, holding, and re-extension based on EMG data. Methods: In total, 20 participants were screened for inclusion. The activities of the longissimus [ES (T12)], erector spinae [ES (L3)], gluteus maximus, and hamstring muscles were examined during forward bending, holding the posture, and re-extension. The mean lumbar flexion angle was used to categorize the patients. Patients with a short hamstring length during forward bending were excluded. Results: The ES (T12) and gluteus maximus : hamstring, and ES (L3) : hamstring activity ratios were compared between the groups during the three phases. The data were normalized to calculate the percent reference voluntary contraction (%RVC). The gluteus maximus : hamstring and ES (L3) : hamstring ratios during re-extension were significantly different between the groups. Conclusions: In the experimental group, the participants showed greater activation of the hamstrings than the gluteus maximus and erector spinae during re-extension. Future studies should include a larger sample size and use more precise eligibility criteria.

Resistive index as a predictor of acute kidney injury caused by an angiotensin converting enzyme inhibitor or angiotensin II receptor blocker in chronic kidney disease patients

( Eun Seok Kim ),( Hyun Jeong Kim ),( Yong Jun Kim ),( Su Mi Lee ),( Ho Jin Lee ),( Duk Song Cho ),( Young Ki Son ),( Seong Eun Kim ),( Ki Hyun Kim ),( Won Suk An ) 대한신장학회 2013 Kidney Research and Clinical Practice Vol.32 No.4

Background: Angiotensin converting enzyme (ACE) inhibitor and angiotensin receptor blocker (ARB) may induce acute kidney injury (AKI). The aim of this study was to evaluate the role of the resistive index (RI), which reflects renal artery resistance on renal duplex ultrasonography, as a predictor of AKI in chronic kidney disease (CKD) patients who are prescribed an ACE inhibitor or ARB. Methods: We screened 105 CKD patients evaluated with renal duplex ultrasonography from 2008 to 2012. We excluded patients not treated with ACE inhibitor or ARB and diagnosed with renal artery stenosis. Finally, we retrospectively analyzed the medical records of 54 patients. AKI was defined as increased serum creatinine by 430% compared with baseline after starting ACE inhibitor or ARB treatment. Results: The mean age of the patients was 60.5713.0 years, serum creatinine level was 1.8570.85 mg/dL and 22.2% of the patients had AKI after the use of an ACE inhibitor or ARB. The RI (P¼0.006) and the percentages of patients with diabetes (P¼0.008) and using diuretics (P¼0.046) were higher in the AKI group. The area under the receiver operating characteristics curve for the prediction of AKI was 0.736 (95% confidence interval¼0.587-0.885, P¼0.013), and RIZ0.80 predicted AKI with 83.3% sensitivity and 61.9% specificity. In the multivariate analysis, RIZ0.80 was an independent prognostic factor [Exp (B)¼8.03, 95% confidence interval ¼1.14-56.74, P¼0.037] for AKI. Conclusion: RIZ0.80 on the renal duplex ultrasonography may be a helpful predictor for AKI in CKD patients who are prescribed an ACE inhibitor or ARB.

Non-Dipper Status and Left Ventricular Hypertrophy as Predictors of Incident Chronic Kidney Disease

An, Hye Rim,Park, Sungha,Yoo, Tae-Hyun,Kang, Shin-Wook,Ryu, Jung-Hwa,Lee, Yong Kyu,Yu, Mina,Ryu, Dong-Ryeol,Kim, Seung Jung,Kang, Duk-Hee,Choi, Kyu Bok The Korean Academy of Medical Sciences 2011 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.26 No.9

<P>We have hypothesized that non-dipper status and left ventricular hypertrophy (LVH) are associated with the development of chronic kidney disease (CKD) in non-diabetic hypertensive patients. This study included 102 patients with an estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m<SUP>2</SUP>. Ambulatory blood pressure monitoring and echocardiography were performed at the beginning of the study, and the serum creatinine levels were followed. During the average follow-up period of 51 months, CKD developed in 11 patients. There was a significant difference in the incidence of CKD between dippers and non-dippers (5.0% vs 19.0%, <I>P</I> < 0.05). Compared to patients without CKD, patients with incident CKD had a higher urine albumin/creatinine ratio (52.3 ± 58.6 mg/g vs 17.8 ± 29.3 mg/g, <I>P</I> < 0.01), non-dipper status (72.7% vs 37.4%, <I>P</I> < 0.05), the presence of LVH (27.3% vs 5.5%, <I>P</I> < 0.05), and a lower serum HDL-cholesterol level (41.7 ± 8.3 mg/dL vs 50.4 ± 12.4 mg/dL, <I>P</I> < 0.05). Based on multivariate Cox regression analysis, non-dipper status and the presence of LVH were independent predictors of incident CKD. These findings suggest that non-dipper status and LVH may be the therapeutic targets for preventing the development of CKD in non-diabetic hypertensive patients.</P>

Structural Transition of Self-Assembled Nanostructures from Dodecyl chain grafted Poly(2-hydroxyethyl aspartamide) in Aqueous solution

Hyun Jin Lee,Eun Jung An,Jong-Duk Kim 한국생물공학회 2007 한국생물공학회 학술대회 Vol.2007 No.10

Synthesis of Heterogeneous Li ₄ Ti ₅ O ₁₂ Nanostructured Anodes with Long-Term Cycle Stability

Lee, Duk Kyu,Shim, Hyun-Woo,An, Jae Sul,Cho, Chin Moo,Cho, In-Sun,Hong, Kug Sun,Kim, Dong-Wan Springer 2010 NANOSCALE RESEARCH LETTERS Vol.5 No.10

<P>The 0D-1D Lithium titanate (Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB>) heterogeneous nanostructures were synthesized through the solvothermal reaction using lithium hydroxide monohydrate (Li(OH)·H<SUB>2</SUB>O) and protonated trititanate (H<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB>) nanowires as the templates in an ethanol/water mixed solvent with subsequent heat treatment. A scanning electron microscope (SEM) and a high resolution transmission electron microscope (HRTEM) were used to reveal that the Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> powders had 0D-1D heterogeneous nanostructures with nanoparticles (0D) on the surface of wires (1D). The composition of the mixed solvents and the volume ratio of ethanol modulated the primary particle size of the Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> nanoparticles. The Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> heterogeneous nanostructures exhibited good capacity retention of 125 mAh/g after 500 cycles at 1C and a superior high-rate performance of 114 mAh/g at 20C.</P>

현장 사례 연구 : 라인사격훈련이 심리기술과 수행에 미치는 영향

안현숙 ( Hyun Sook An ),장덕선 ( Duk Sun Chang ) 한국스포츠정책과학원(구 한국스포츠개발원) 2006 체육과학연구 Vol.17 No.2

본 연구는 중학교 소총 사격선수를 대상으로 실험집단과 통제집단으로 구분하여 연구자가 고안한 라인사격훈련이 심리기술과 수행에 미치는 영향을 조사하였다. 라인사격훈련은 Table 사격, 거리조절 사격, 라인사격으로 구성되었으며, 4주 훈련을 전후하여 선수들의 특성불안, 특성자신감, 사격심리기술의 변화추이와 SCAT system을 이용한 라인사격 전·후의 수행기록, 2개의 공식대회 기록을 바탕으로 라인사격훈련의 구체적 효과를 입증하였다. SCATT system에 의한 사전-사후 변화에 따른 두 집단의 요인별 비교를 보면, 실험집단이 조준시간과 조준 길이가 단축되고 총점수가 증가하였다. 심리기술의 변화를 보면, 실험집단은 심상조절, 주의집중/불안, 성취동기, 각성조절, 자신감이 증가되었다. 통제집단은 심상조절과 주의집중/불안은 낮아지고 각성조절과 자신감은 약간 향상되었다. 또한 특성불안 및 특성자신감의 사후-사전의 변화에 따른 두 집단의 비교에서는 차이가 없었다. This study tried to verify the effect of line-shooting by analyzing the athletes` progress through the training for the performance strategy of table shooting, distance shooting, and line shooting. We also proved the effect of line shooting training in a concrete way by recording the performance before and after the performance strategy using SCATT system. We considered psychological factors by doing the questionnaire about specific anxiety, specific self-confidence, and psychological skills of shooting. The experimental group improved their aiming skill minutely in long-distance shooting(11m, line target 3mm) with acting delicately or moving slowly down so on. The experimental group improved their shooting skill, comparing the progress of the control group, before and after SCATT system. In psychological skills, the changes of the experimental group are controling mental imagery naturally, handling attention and anxiety, having better motivation for achievement, controling arousal, and gaining confidence more. The control group improved arousal management and gained confidence more. There was no difference between before and after the training in specific anxiety and specific confidence. No specific difference couldn`t be found, but we could identify the effect of the training in the result of an in-depth interview.

Clinical Research Article : Analysis of expert consultation referrals for anesthesia-related issues (December 2008-July 2010): KSA Legislation committee report

( Kook Hyun Lee ),( Tae Hun An ),( Jong Ho Choi ),( Dong Gun Lim ),( Yeong Ju Lee ),( Duk Kyung Kim ) 대한마취과학회 2011 Korean Journal of Anesthesiology Vol.60 No.4

Background: Since 2009, database construction of anesthesia-related adverse events has been initiated through the legislation committee of the Korean Society of Anesthesiologists (KSA), based on expert consultation referrals provided by police departments, civil courts, and criminal courts. Methods: This study was a retrospective descriptive analysis of expert consultation referrals on surgical anesthesia-related cases between December 2008 and July 2010. Results: During the given period, 46 surgical anesthesia-related cases were referred to the KSA legislation committee for expert consultation. Because six cases were excluded due to insufficient data, 40 cases were included in the final analysis. Of 40 cases, 29 (72.5%) resulted in death. Respiratory events were most common in both surviving/disabled and dead patients (36.4 vs. 51.7%, respectively; P > 0.05). Overall, respiratory depression due to the drugs used for monitored anesthesia care (MAC) was the most common specific mechanism (25%), in which all but one case (profound brain damage) resulted in death. In all of these cases, surgeons or physicians provided MAC without the help of anesthesiologists. Conclusions: Overall, the most common damaging mechanism was related to respiratory depression due to sedatives or anesthetics used for MAC. Almost all MAC injury cases are believed to be preventable with the use of additional or better monitoring and an effective response to initial physiological derangement. Thus, it is essential to establish practical MAC guidelines and adhere to these guidelines strictly to reduce the occurrence of severe anesthesia-related adverse outcomes. (Korean J Anesthesiol 2011; 60: 260-265)

Evacuation Guidance Robot System for Victims in Disaster Site

Young-Duk Kim,Yoon-Gu Kim,Seung-Hyun Lee,Jeong-Ho Kang,Jinung An 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

Robot technology is emerging in applications for the disaster prevention purpose such as fire-fighting robot, rescue robot, and surveillance robot. This paper suggests an evacuation guidance robot system able to be thrown into the disaster site, investigate the environment information, search displaced people, and evacuate them from disaster site. This spool-like small and light mobile robot can be easily carried and remotely controlled by means of laptop-sized tele-operator. It contains functional units that are a camera to capture the disaster site, sensors to gather temperature, CO gas, and oxygen concentration, and microphone with speaker for emergence voice communication between firemen and victims. The robot has also designed to be capable of high temperature protection, excellent waterproofing, and high impact resistance. The laboratory tests are carried out for the performance evaluation of the proposed evacuation guidance robot system.