• Journal of Ginseng Research
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• 제38권4호
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• pp.233-238
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• 2014

Background: The actin cytoskeleton in podocytes is essential for the maintenance of its normal structure and function. Its disruption is a feature of podocyte foot-process effacement and is associated with proteinuria. ${\alpha}$-Actinin-4 in podocytes serves as a linker protein binding the actin filaments of the cytoskeleton. Methods: To investigate the effect of ginseng total saponin (GTS) on the pathological changes of podocyte ${\alpha}$-actinin-4 induced by diabetic conditions, we cultured mouse podocytes under normal glucose (5mM) or high glucose (HG, 30mM) conditions, with or without the addition of advanced glycosylation end products (AGE), and treated with GTS. Results: In confocal imaging, ${\alpha}$-actinin-4 colocalized with the ends of F-actin fibers in cytoplasm, but diabetic conditions disrupted F-actin fibers and concentrated ${\alpha}$-actinin-4 molecules at the peripheral cytoplasm. GTS upregulated ${\alpha}$-actinin protein in a time- and dose-dependent manner, and suppressed the receptor for AGE levels in western blotting. Diabetic conditions, including HG, AGE, and both together, decreased cellular ${\alpha}$-actinin-4 protein levels at 24 h and 48 h. Such quantitative and qualitative changes of ${\alpha}$-actinin-4 protein induced by diabetic conditions were mitigated by GTS. Conclusion: These findings imply that both HG and AGE have an influence on the distribution and amount of ${\alpha}$-actinin-4 in podocytes that can be recovered by GTS.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.3021-3024
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• 2009

$Zn_2Ti_{1-x}Fe_xO_4\;(0\;{\leq}\;x\;{\leq}\;0.7)$ photocatalysts were synthesized by polymerized complex (PC) method and investigated for its physico-chemical as well as optical properties. $Zn_2Ti_{1-x}Fe_xO_4$ can absorb not only UV light but also visible light region due to doping of Fe in the Ti site of $Zn_2TiO_4$ lattice because of the band transition from Fe 3d to the Fe 3d + Ti3d hybrid orbital. The photocatalytic activity of Fe doped $Zn_2TiO_4$ samples for hydrogen production under UV light irradiation decreased with an increase in Fe concentration in $Zn_2TiO_4$. Consequently, there exists an optimized concentration of iron for improved photocatalytic activity under visible light (${\lambda}{\leq}$420 nm)

• 디지털콘텐츠학회 논문지
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• 제18권5호
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• pp.911-921
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• 2017

이 연구는 영상콘텐츠 분야가 정권별로 어떤 의미 구조를 형성하고 있는지 분석하기 위해 의미연결망 분석 기법을 적용했다. 연구대상은 영상콘텐츠 석박사학위논문의 초록을 대상으로, 시기는 문화산업 도입기인 1993년부터 2016년까지이다. 분석대상 단어는 정권별 최상위 출현단어인 영상, 미디어, 교육, 콘텐츠 등 4개 언어의 의미연결망을 분석하였다. 분석방법에는 빅데이터 분석기법인 텍스트 마이닝과 의미연결망 분석을 활용했고, 분석프로그램으로는 R을 사용했다. 연구결과는 다음과 같다. 첫째, '교육'에 대한 영향력 감소이다. 초기 영상콘텐츠 분야는 영상과 관련한 '교육', 어떻게 '표현'할 것인지에 대한 연구들이 많이 실시되었으나 점차 감소 추세를 보였다. 둘째, '미디어'의 역할 변화이다. 중기의 영상콘텐츠 분야는 영상을 전달하는 수단인 '미디어'에 대한 연구들이 주로 실시되었으며, 더불어 '디지털' 기술에 대한 연구들이 강세를 보였다. 마지막으로 '콘텐츠' 위상의 변화이다. 노무현 정부를 시작으로 내용물의 질에 관련한 '콘텐츠'에 대한 관심이 증대하였으며, <박근혜정부>에는 '영상'과 '콘텐츠'의 위상이 거의 동등해져 연구들이 실시되었다.

• The Journal of Advanced Prosthodontics
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• 제2권1호
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• pp.7-13
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• 2010

Although most researchers agree that platelet-rich plasma (PRP) is a good source of autogenous growth factors, its effect on bone regeneration is still controversial. The purpose of this study was to evaluate whether increasing angiogenic factors in the human PRP to enhance new bone formation through rapid angiogenesis. MATERIAL AND METHODS. In vitro, the human platelets were activated with application of shear stress, $20\;{\mu}g/ml$ collagen, 2 mM $CaCl_2$ and 10U thrombin/$1\;{\times}\;10^9$ platelets. Level of vascular endothelial growth factor (VEGF) and platelet microparticle (PMP) in the activated platelets were checked. In the animal study, human angiogenic factors-enriched PRP was tested in 28 athymic rat's cranial critical bone defects with $\beta$-TCP. Angiogenesis and osteogenesis were evaluated by laser Doppler perfusion imaging, histology, dual energy X-ray densinometry, and micro-computed tomography. RESULTS. In vitro, this human angiogenic factors-enriched PRP resulted in better cellular proliferation and osteogenic differentiation. In vivo, increasing angiogenic potential of the PRP showed significantly higher blood perfusion around the defect and enhanced new bone formation around acellular bone graft material. CONCLUSION. Angiogenic factor-enriched PRP leads to faster and more extensive new bone formation in the critical size bone defect. The results implicate that rapid angiogenesis in the initial healing period by PRP could be supposed as a way to overcome short term effect of the rapid angiogenesis.

• 센서학회지
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• 제24권5호
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• pp.319-325
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• 2015

While the conventional personal protective equipments (PPEs) covers a variety of devices and garments such as respirators, turnout gear, gloves, blankets and gas masks, several electronic devices such as personal alert safety system (PASS) and heads-up displays in the facepiece have become a part of firefighters personal protective equipments through past several years. Furthermore, more advanced electronic sensors including location traking sensor, thermal imaging caerma, toxic gas detectors, and even physiological monitoring sensors are being integrated into ensemble elements for better protection of firefighters from fire sites. Despite any electronic equipment placed on the firefighter must withstand environmental extremes and continue to properly function under any thermal conditions that firefighters routinely face, there are no specific criteria for these electronics to define functionability of these devices under given thermal conditions. Although manufacturers provide the specifications and performance guidelines for their products, their operation guidelines hardly match the real thermal conditions. Present study overviews firefighter's fatalities and thermal conditions that firefighters and their equipments face. Lastly, thermal packaging methods that we have developed and tested are introduced.

• 한국콘텐츠학회논문지
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• 제13권9호
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• pp.288-294
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• 2013

흉부 디지털토모장치는 가장 발달한 촬영방법중의 하나이지만 일반 흉부촬영방법에 비해 환자의 피폭선량이 높다는 단점이 있다. 이런 이유 때문에 본 연구는 흉부 디지털토모영상에서 부가여과를 사용하여 환자선량을 저감시키는 방법을 검토하여 보았으며, 화질의 변화도 실험하였다. 그 결과 부가여과가 없는 장치의 기본상태에서 피부입사선량, 면적선량, 실효선량은 1.95 mGy, 17.66 $dGycm^2$, 0.133 mSv로, 부가여과사용시는 0.312 mGy, 2.27 $dGy.cm^2$, 0.052 mSv로 나타나 선량이 각 각 66.2%, 73.6%, 57.4%로 감소하였다. 화질에서 병소의 검출율은 중심부 미소병소 검출율(p < .001)을 제외한 나머지 주변부, 중심부병변 및 주변부 미소병소에서는 두 방법에서 큰 차이를 보이지 않았으며, 환자의 선량감소에는 큰 효과를 볼 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제35권5호
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• pp.151-159
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• 2014

Computed tomography (CT) is one of the most widely used medical imaging modality. However, substantial x-ray dose exposed to the human subject during the CT scan is a great concern. Region-of-interest (ROI) CT is considered to be a possible solution for its potential to reduce the x-ray dose to the human subject. In most of ROI-CT scans, the ROI is set to a circular shape whose diameter is often considerably smaller than the full field-of-view (FOV). However, an arbitrarily shaped ROI is very desirable to reduce the x-ray dose more than the circularly shaped ROI can do. We propose a new method to make a non-circular convex-shaped ROI along with the image reconstruction method. To make a ROI with an arbitrary convex shape, dynamic collimations are necessary to minimize the x-ray dose at each angle of view. In addition to the dynamic collimation, we get the ROI projection data with slightly lower sampling rate in the view direction to further reduce the x-ray dose. We reconstruct images from the ROI projection data in the compressed sensing (CS) framework assisted by the exterior projection data acquired from the pilot scan to set the ROI. To validate the proposed method, we used the experimental micro-CT projection data after truncating them to simulate the dynamic collimation. The reconstructed ROI images showed little errors as compared to the images reconstructed from the full-FOV scan data as well as little artifacts inside the ROI. We expect the proposed method can significantly reduce the x-ray dose in CT scans if the dynamic collimation is realized in real CT machines.

• Journal of Chest Surgery
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• 제40권2호
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• pp.128-131
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• 2007

da $Vinci^{TM}$ 수술로봇(da $Vinci^{TM}$ Surgical System)은 삼차원영상시스템과 사람의 손동작을 재현할 수 있는 로봇팔을 갖추고 있어, 최소절개를 통한 제한된 공간에서도 입체시야에서 다양한 수술을 시행할 수 있도록 해줌으로써, 최소침습적수술의 장점을 극대화할 수 있도록 해준다. 저자들은 심방중격결손에 대하여 da $Vinci^{TM}$ 수술로봇을 이용한 개심수술을 성공적으로 시행하였기에 보고하는 바이다.

• Journal of Korean Neurosurgical Society
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• 제39권3호
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• pp.210-214
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• 2006

Objective : We investigate risk factors of cerebral microbleeds[MBs] and their relation to concomitant magnetic resonance[MR] findings in intracerebral hemorrhages[ICHs] patients. Methods : We studied 100 consecutive patients with primary ICH over a 1-year period. These patients underwent brain MR images using 3.0-T scanners within the first week of the hemorrhage. MBs and old hematomas were located and counted by using $T2^*-weighted$ gradient-echo MR imaging. We also counted lacunes and graded white matter and periventricular hyperintensity on T1- and T2-weighted spin-echo sequences. The association between MBs and vascular risk factors and MR abnormalities were analyzed. Results : MBs were seen in 77 of ICH patients, and their number ranged from 1 to 65 lesions [mean 11, median 6]. The locations of MBs were subcortex-cortex [40.6%], basal ganglia [26.7%], thalamus [14.1 %], brain stem [12.5%], and cerebellum [9.1 %]. Analysis of clinical data revealed that age, hypertension, history of stroke, and duration of hypertension were frequently associated with MBs. The incidence of lacunes, old hematomas, and advanced leukoaraiosis was significantly higher in the MBs group, compared with the patients without MBs. Conclusion : MBs are frequently observed in ICH patients with advancing age, chronic hypertension, and previous hemorrhagic stroke, and are also closely related with morphological signs of occlusive type microangiopathy, such as lacunar infarct and severe leukoaraiosis.

• 대한금속재료학회지
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• 제50권5호
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• pp.401-406
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• 2012

When viewed using a magnetic resonance imaging (MRI) system, invasive materials inside the human body, in many cases, severely distort the MR image of human tissues. The degree of the MR image distortion increases in proportion not only to the difference in the susceptibility between the invasive material and the human tissue, but also to the intensity of the magnetic field induced by the MRI system. In this study, by blending paramagnetic Ti particles with diamagnetic graphite, we synthesized $Ti_{100-x}C_x$ composites that can reduce the artifact in the MR image under the high-strength magnetic field. Of the developed composites, $Ti_{70}C_{30}$ showed the magnetic susceptibility of ${\chi}=67.6{\times}10^{-6}$, which corresponds to 30% of those of commercially available Ti alloys, the lowest reported in the literature. The level of the MR image distortion in the vicinity of the $Ti_{70}C_{30}$ composite insert was nearly negligible even under the high magnetic field of 4.7 T. In this paper, we reported on a methodology of designing new structural materials for bio-applications, their synthesis, experimental confirmation and measurement of MR images.