Expression of cellular retinoic acid-binding protein-I (CRABP-I) in the cerebrospinal fluid of adult onset moyamoya disease and its association with clinical presentation and postoperative haemodynamic change

Jeon, Jin Sue,Ahn, Jun Hyong,Moon, Youn-joo,Cho, Won-Sang,Son, Young-Je,Kim, Seung-Ki,Wang, Kyu-Chang,Bang, Jae Seung,Kang, Hyun-Seung,Kim, Jeong Eun,Oh, Chang Wan BMJ Publishing Group Ltd 2014 Journal of neurology, neurosurgery and psychiatry Vol.85 No.7

<P><B>Objective</B></P><P>The elevation of cellular retinoic acid-binding protein-I (CRABP-I) has been suggested as a candidate in the pathogenesis of paediatric moyamoya disease (MMD). However, few studies have addressed CRABP-I in adult onset MMD. The aim of this study was to examine the expression of CRABP-I in the cerebrospinal fluid (CSF) of adult onset MMD, and to evaluate its association with clinical presentation and postoperative haemodynamic change.</P><P><B>Methods</B></P><P>This study examined the CSF from 103 patients: bilateral MMD, n=58 (56.3%); unilateral MMD, n=19 (18.4%); atherosclerotic cerebrovascular disease (ACVD), n=21 (20.4%); and control group, n=5 (4.9%). The intensity of CRABP-I was confirmed by western blotting and expressed as the median (25th–75th percentile). The differences in CRABP-I expression according to disease entity (unilateral MMD vs bilateral MMD vs ACVD), initial presenting symptoms (haemorrhage vs ischaemia) and postoperative haemodynamic change (vascular reserve in single photon emission CT and basal collateral vessels in digital subtraction angiography) were analysed.</P><P><B>Results</B></P><P>CRABP-I intensities in bilateral MMD (1.45(0.86–2.52)) were significantly higher than in unilateral MMD (0.91(0.78–1.20)) (p=0.044) or ACVD (0.85(0.66–1.11)) (p=0.004). No significant differences were noted based on the initial presenting symptoms (p=0.687). CRABP-I was not associated with improvement in vascular reserve (p=0.327), but with decrease in basal collateral vessels (p=0.023) postoperatively.</P><P><B>Conclusions</B></P><P>Higher CRABP-I in the CSF can be associated with typical bilateral MMD pathogenesis in adults. Additionally, postoperative basal collateral change may be related to the degree of CRABP-I expression.</P>

A Time-Strain Separable K-BKZ Constitutive Equation to Describe the Large Amplitude Oscillatory Shear (LAOS) Flow Behavior of Viscoelastic Polymer Liquids

안혜진,장갑식,송기원,Ahn, Hye-Jin,Chang, Gap-Shik,Song, Ki-Won The Korean Fiber Society 2017 한국섬유공학회지 Vol.54 No.4

The present study has been designed to describe the nonlinear viscoelastic behavior of concentrated polymer systems in large amplitude oscillatory shear (LAOS) flow fields using a time-strain separable K-BKZ constitutive equation (i.e., Wagner model). Using an Advanced Rheometric Expansion System (ARES), the dynamic viscoelastic behavior of aqueous poly(ethylene oxide) (PEO) solutions with various molecular weights and different concentrations has been investigated with a various combination of several fixed strain amplitudes and constant angular frequencies. The linear dynamic data (storage modulus and loss modulus) over a wide range of angular frequencies were obtained to determine the relaxation spectrum parameters and the stress relaxation moduli at various deformation magnitudes were measured to determine the damping function. The effects of the number of relaxation spectrum parameters and damping functions on the prediction results of the Wagner model were examined in depth. The nonlinear viscoelastic functions were analyzed by the aid of 3D plots and predicted over a wide range of strain amplitudes to evaluate the overall predictability of the Wagner model. The main findings obtained from this study are summarized as follows : (1) The Lissajous patterns predicted by the Wagner model are in good coincidence with the experimentally obtained stress-strain rate hysteresis loops both in linear and nonlinear viscoelastic regions and are independent of the number of relaxation spectrum parameters used in the calculation of memory function. (2) The effect of damping function on the predictive ability of the Wagner model is more sensitive than that of memory function. When the damping function is smaller than that of the experimental data, the stress amplitude predicted by the Wagner model also becomes smaller. (3) The Wagner model predictions are closely coincident with the experimental results in the linear viscoelastic region. As the strain amplitude is increased, the predicted nonlinear viscoelastic functions are somewhat larger than that of the experimental data. Nevertheless, all trends of the nonlinear viscoelastic behavior are in good agreement with the experimental results in a qualitative sense. (4) The Wagner model predicts the first harmonic loss modulus more exactly than the first harmonic storage modulus. As the strain amplitude is increased, the first harmonic storage modulus is somewhat overpredicted. The third and fifth harmonic storage and loss moduli exhibit an overshoot or an undershoot at large strain amplitudes. This constitutive equation has an ability to qualitatively describe well such dramatic behavioral changes.

Aggressive Variant of Chromophobe Renal Cell Carcinoma Accompanied by Tonsillar Squamous Cell Carcinoma

Min Chul Cho,Chang Ahn,Ji Hyeon Roh,Jungbum Bae,Jong Sun Choi,Eo-Jin Kim,Hae Won Lee,Kwang Soo Lee 대한비뇨기종양학회 2013 대한비뇨기종양학회지 Vol.11 No.2

Chromophobe renal cell carcinoma (ChRCC) is a distinct histologic subtype of RCC and accounts for approximately 5% to 10%. The prognosis for ChRCC is considered to be better than those for other types of RCC. Sarcomatoid transformation occasionally occurs and has been presented as a predicting factor of poor prognosis. However, there has been a scarcity of reports on aggressive type of ChRCC without sarcomatoid change. Here we report an unusual case of aggressive variant of ChRCC with hilar lymph node metastasis, with tumor necrosis and without sarcomatoid change. In addition, this case was accompanied by synchronous occurrence of tonsillar squamous cell carcinoma.

6-OHDA가 흰쥐 등쪽솔기핵내 도파민성 신경세포와 별아교세포에 미치는 영향

홍은석(Eun Seog Hong),남성안(Seong Ahn Nam),조승묵(Seung Mook Jo),강태천(Tae-Cheon Kang),원무호(Moo Ho Won),최창도(Chang Do Choi) 대한해부학회 1999 Anatomy & Cell Biology Vol.32 No.4

신경독성물질인 6-hydroxydopamine (6-OHDA)이 중추신경계통 내 도파민성 신경세포에 미치는 영향과 이에 따른 별아교 세포들의 반응을 형태학적으로 규명하고자 본 연구를 시행하였다. 흰쥐의 가쪽뇌실에 6-OHDA를 투여한 후 면역조직화학 염색을 시행하여 광학현미경 하에서 등쪽솔기핵 내 도파민성 신경세포에 나타나는 퇴행성변화와 주위 별아교세포들의 반응양상 등을 경시적으로 제 3일, 제 5일, 제10일 및 제20일에서 관찰하였던 바 아래와 같은 결과를 얻었다. 6-OHDA에 의한 도파민성 신경세포의 퇴행성변화는 약물투여후 제 3일군에서 세포돌기가 팽대되고, 제 5일군과 제 10일군에서는 세포돌기의 소실과 함께 세포체가 위축되었고, 제20일군에서는 세포체가 소실되었다. 또한 6-OHDA에 의해 도파민성 신경세포들의 손상이 진행되면서 별아교세포들의 반응양상은 제 5일에서 대조군에 비해 급격하게 증가하였으며, 제20일에 이르러 최고값을 보였다. 이상의 결과로부터 6-OHDA가 중추신경계통 내 도파민성 신경세포들에 선택적이고 강한 세포독성을 유발하여 퇴행성 변화가 진행되고, 세포 손상이 시간 경과에 따라 진행되면서 주위의 별아교세포들이 지속적으로 증가된 활동을 보인다는 사실을 알게 되었다. This study was designed to clarify the cytotoxic effects of 6-hydroxydopamine (6-OHDA) on the dopaminergic neurons and astrocytes in the dorsal raphe nucleus (DRN), and to investigate neurodegenerative changes by immunohistochemistry. Adult male rats (Sprague-Dawley strain) weighing from 250 to 350 g were used as experimental animals. 6-OHDA (100 μg dissolved in 0.1% ascorbic acid) was injected into the lateral ventricle of the rat brain with the Hamilton syringe. The control rats were treated with the similar volume of 0.1 % ascorbic acid. The rats were sacrificed at the 3rd, 5th, 10th and 20th day, respectively, after the injection of 6-OHDA. The cytotoxicity of 6-OHDA resulted in severe neurodegeneration of the dopaminergic neurons in the DRN. In the 3rd day, the dopaminergic fibers were dilated. In the 5th and 10th days, the dopaminergic fibers were depleted, and dopaminergic cell bodies were shrunken. In the 20th day, the dopaminergic cell bodies were almost completely disappeared. Astroglial reactions induced by 6-OHDA were also observed in the DRN. In the 5th day, astrocytes were significantly increased as compared with that of the control value. The value were reached at its maximum by the 20th day. Based on the present results, it suggests that 6-OHDA may act as a specific neurotoxin to dopaminergic neurons in the DRN, and induce severe neurodegenerative changes. Also, it suggests that the astroglial reaction in the DRN is gradually activated during the neurodegerative changes

PV 모듈의 손실 저항 성분을 고려한 I-V 출력 모델링에 관한 연구

홍종경(Jong-kyuong Hong),정태희(Tae-hee Jung),류세환(Se-Hwan Ryu),원창섭(Chang-sub Won),강기환(Gi-Hwan Kang),안형근(Hyungkeun Ahn),한득영(Deuk-Young Han) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.10

This paper, we proposed the theoretical model which includes series resistance R<SUB>s</SUB> and shunt resistance R<SUB>sh</SUB> of single-crystalline PV module and used numerical method based on physics. Series resistance R<SUB>S</SUB> was derived from approach for p-n junction diode instead of established form obtained from the simulator with irradiance changes. Electrical output characteristics for PV modules to count the effect of R<SUB>s</SUB> were then studied. Finally simulation results were compared to experimental data leading to good agreement.

Assessment of Change of Intrahepatic Fat Amount Using Controlled Attenuation Parameter in Clinical Trial

( Sang Bong Ahn ),( Dae Won Jun ),( Jae Yoon Jeong ),( Joo Hyun Sohn ),( Chang Hong Lee ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: Multi-echo modified Dixon (mDixon) sequence (MR-PDFF) is asafe and non-invasive alternative for the quantification of hepaticfat content. And it has accepted reasonable method to assess thechange of hepatic fat amount in phase II study. Recently controlledattenuation parameter (CAP) has been showed good correlation withintrahepatic fat amount compare to liver biopsy as well as MRS data in large cross sectional cohort. However there is little known whetherchange of CAP scores can be used in clinical trial. We investigatedthe correlation with CAP and MRS by serial examination in clinicaltrial setting.Methods: Sixty-five NAFLD patients were evaluated with MRS andtransient elastography including CAP in clinical study. Both MRS andCAP were evaluated after three month probiotic clinical trial in patientswith NAFLD.Results: Baseline CAP and MR-PDFF showed good correlation assessinghepatic steatosis (r=0.60, p<0.001). Also, changes of CAP value wasalso correlated with changes of intra-hepatic fat % using MR-PDFF(r=0.35, p=0.008) in clinical trial setting. Concordance rate of improvementor aggravation was comparable in both two methods. However,the less change amount was small in CAP value, the less concordancerate showed more weak with MR-PDFF. When the change of CAPvalue after treatment was less than 20, concordance rate withMR-PDFF was decreased to 15/25 (60%).Conclusions: CAP and MRS have a comparable diagnostic value forthe hepatic steatosis quantification as well as assessing changes ofhepatic fat amount in clinical trial. However, a careful interpretationof the steatosis change using CAP score should be given when theabsolute change value was less than 20 in clinical trial setting.

Characteristics of Fluid Flow and Heat Transfer in a Fluidized Heat Exchanger with Circulating Solid Particles

Ahn, Soo-Whan,Lee, Byung-Chang,Kim, Won-Cheol,Bae, Myung-Whan,Lee, Yoon-Pyo The Korean Society of Mechanical Engineers 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.9

The commercial viability of heat exchanger is mainly dependent on its long-term fouling characteristic because the fouling increases the pressure loss and degrades the thermal performance of a heat exchanger. An experimental study was performed to investigate the characteristics of fluid flow and heat transfer in a fluidized bed heat exchanger with circulating various solid particles. The present work showed that the higher densities of particles had higher drag force coefficients, and the increases in heat transfer were in the order of sand, copper, steel, aluminum, and glass below Reynolds number of 5,000.

Electrical Properties of Lead-free Bi3.25La0.75(Ti1-xVx)3O12 Ceramics

Chang Won Ahn,Ill Won Kim,Byung Moon Jin,Hai Joon Lee,Jae Shin Lee,Jin Soo Kim,Mun Seok Choi,Sung Young Lee 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1

Vanadium-doped bismuth lanthanum titanate lead-free Bi3:25La0:75(TixVx)3O12 (x = 0 0.10;BLTV-x) ceramics have been fabricated by using a solid-state reaction method. BLTV-0.01 ceramics exhibit a relatively high electromechanical coupling factor (kt = 20.2 %) and high remnant polarization (Pr = 11.7 C/cm2). Vanadium substitution for titanium-ion site can eectively enhance the resistivity by one order of magnitude(1.74 1011cm). A small amount of vanadium substitution for titanium site on BLT can signicantly reduce the space charge density and the in uence of domain pinning, which would be responsible for the improvement in the ferroelectricity and piezoelectricity.

Rapid Prototyping and Testing of 3D Micro Rockets Using Mechanical Micro Machining

Won-Shik Chu,Chang- II Beak,Sung-Hoon Ahn,Tae-Hwan Cho 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.1

The trend of miniaturization has been applied to the research of rockets to develop prototypes of micro rockets. In this paper, the development of a web-integrated prototyping system for three-dimensional micro rockets, and the results of combustion tests are discussed. The body of rocket was made of 6061 aluminum cylinder by lathe process. The three-dimensional micro nozzles were fabricated on the same aluminum by using micro endmills with φ100 ㎛ - φ500 ㎛ diameter. Two types of micro nozzle were fabricated and compared for performance. The total mass of the rockets was 7.32 g and that of propellant (gun powder) was 0.65 g. The thrust-to-weight ratio was between 1.58 and 1.74, and the flight test with 45 degree launch angle from the ground resulted in 46 m - 53 m of horizontal flight distance. In addition, ABS housing for the micro machined rocket was fabricated using Fused Deposition Modeling (FDM). A web-based design, fabrication, and test system for micro nozzles was proposed to integrate the distributed hardware resources. Test data was sent to the designer via the same web server for the faster feedback to the rocket designer.

Gate Leakage Current of Power GaAs MESFET's at High Temperature

Chang-sub Won,Hyungkeun Ahn,Deuk-Young Han 전력전자학회 2001 ICPE(ISPE)논문집 Vol.2001 No.10

Increase of gate leakage current causes decrease of gain and increase of noise In this paper, gate leakage current of GaAs MESEFTs' has been traced with different temperatures from 27℃ to 350℃ to obtain the zero voltage saturation current Js which is critical to the temperature dependency of total current From the results, thermal leakage current coefficient has been proposed to compensate for the total current due to the thermionic emission, tunneling, generation and/or hole injection.<br/>