• Toxicological Research
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• 제24권1호
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• pp.37-44
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• 2008

The in vitro cell transformation assays (CTA) were performed using BALB/3T3 murine fibroblasts and HaCaT human keratinocytes in order to evaluate concordance between both in vitro CTAs and carcinogenicity with compounds differing in their genotoxic and carcinogenic potential. Six test articles were evaluated, two each from three classes of compounds: genotoxic carcinogens (2-amino-5-nitrophenol and 4-nitroquinoline-N-oxide), genotoxic noncarcinogens (8-hydroxyquinoline and benzyl alcohol), and nongenotoxic carcinogens (methyl carbamate and N-nitrosodiphenylamine). Any foci of size $\geq$2 mm regardless of invasiveness and piling was scored as positive in CTA with BALB/3T3. As expected, four carcinogens regardless of their genotoxicity had positive outcomes in two-stage CTA using BALB/3T3 cells. However, of the two genotoxic noncarcinogens, benzyl alcohol was positive CTA finding. We concluded that, of the 6 chemicals tested, the sensitivity for BALB/3T3 system was reasonably high, being 100%. The respective specificity for BALB/3T3 assay was 50%. We also investigated the correlation between results of BALB/3T3 assay and results from HaCaT assay in order to develop a reliable human cell transformation assay. However, evaluation of staining at later time points beyond the confluency stage did not yield further assessable data because most of HaCaT cells were detached after $2{\sim}3$ days of confluency. Thus, after test article treatment, HaCaT cells were split before massive cell death began. In this modified protocol for this HaCaT system, growing attached colonies were counted instead of transformed foci 3 weeks since last subculture. Compared to BALB/3T3 assay, HaCaT assay showed moderate low sensitivity and high specificity. Despite these differences in specificity and sensitivity, both cell systems did exhibit same good concordance between in vitro CTA and rodent carcinogenicity findings (overall 83% concordant results). At present the major weakness of these in vitro CTA is lack of validation for regulatory acceptance and use. Thus, more controlled studies will be needed in order to be better able to assess and quantitatively estimate in vitro CTA data.

• Journal of Trauma and Injury
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• 제22권2호
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• pp.184-192
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• 2009

Purpose: This study was conducted to evaluate the effectiveness of the treatment strategy of transcatheter arterial embolization after pelvic CT angiography (CTA) in cases of traumatic pelvic hemorrhage. Methods: This is a retrospective analysis of pelvic hemorrhage patients who underwent transcatheter arterial embolization after pelvic CTA at our regional emergency center during a 31-month period. We reviewed the medical records and imagings of all these patients. Results: Transcatheter arterial embolization was performed in 17 patients (M:F=7:10, mean age=53.9) who underwent pelvic CTA for the evaluation of traumatic pelvic hemorrhage. Arterial bleeding was demonstrated on pelvic CTA in all patients, and the combined injury was also noted in 13 patients. The admission-to-CTA time was $84.53{\pm}66.92$ minutes, and the CTA-to-embolization time was $147.65{\pm}99.97$ minutes. Extravasation of contrast media or pseudoaneurysm was demonstrated on conventional angiography in all patients. Unilateral iliac artery embolization was performed in 8 patients, and bilateral iliac artery embolization was performed in 9 patients. Additional embolizations other than in the iliac arteries were performed in 7 patients. Initial hemostasis was achieved in 16 patients. One patient died of ongoing pelvic bleeding. Rebleeding occurred in only one patient and hemostasis was achieved with the second embolization. Another patient died of intracranial and facial bleeding in spite of pelvic hemostasis. The overall mortality was 11.8%, and there was no significant adverse effects in the other patients. Conclusion: Transcatheter arterial embolization after pelvic CTA is an effective treatment strategy in the management of traumatic pelvic hemorrhage patients.

• 폴리머
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• 제36권3호
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• pp.351-356
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• 2012

디스플레이 전자 장치의 제작에 사용되는 대표적인 유기물첨가제는 아크릴 바인더이다. 이 아크릴 바인더는 라디칼 중합으로 제조되는데 본 연구에서는 glycidyl methacrylate(GMA), methyl methacrylate(MMA), methacrylic acid(MAA)를 이용하여 공중합을 시도하였다. 그리고 이 공중합체의 접착력 향상을 위해서 실란계 mercaptane 화합물을 사슬 이동제(CTA)로 사용하였다. 본 연구에서 사용된 CTA는 (3-mercaptopropyl) trimethoxysilane(MPTMS)이며, 제조된 공중합체들의 분자량, 코팅의 두께, 투과도, 접착력 등의 물성 등을 살펴보았다. 사용된 MPTMS 함량에 따라 분자량이 조절되었고, MPTMS의 함량이 증가할수록 접착력이 향상되었다.

• 한국군사과학기술학회지
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• 제9권1호
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• pp.50-59
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• 2006

Lately, there exist growing demands for the use of CTAs(Cased Telescoped Ammunitions) to increase the firepower of mid-calibre automatic guns despite spatial limitations of armament. In this paper, for automatic CTA guns a rotating chamber mechanism is designed based on parallel index concept. Via dynamic simulations it proves capable of smooth operation even at as high a firing rate as 200spm. Subsequently, motor controllers are synthesized to drive the chamber at any constant speed and also to control positions in the presence of large disturbances caused by the intermittently-rotating load. It is remarkable that we successfully adopted a disturbance observer to treat disturbances only with a moderate bandwidth of the closed-loop system.

• Journal of International Society for Simulation Surgery
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• 제2권1호
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• pp.17-25
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• 2015

Purpose In this paper, we propose a robust 3D vessel tracking algorithm by utilizing an active contour model and unscented Kalman filter which are the two representative algorithms on segmentation and tracking. Materials and Methods The proposed algorithm firstly accepts user input to produce an initial estimate of vessel boundary segmentation. On each Computed Tomography Angiography (CTA) slice, the active contour is applied to segment the vessel boundary. After that, the estimation process of the unscented Kalman filter is applied to track the vessel boundary of the current slice to estimate the inter-slice vessel position translation and shape deformation. Finally both active contour and unscented Kalman filter are inter-operated for vessel segmentation of the next slice. Results The arbitrarily shaped blood vessel boundary on each slice is segmented by using the active contour model, and the Kalman filter is employed to track the translation and shape deformation between CTA slices. The proposed algorithm is applied to the 3D visualization of chest CTA images using graphics hardware. Conclusion Through this algorithm, more opportunities, giving quick and brief diagnosis, could be provided for the radiologist before detailed diagnosis using 2D CTA slices, Also, for the surgeon, the algorithm could be used for surgical planning, simulation, navigation and rehearsal, and is expected to be applied to highly valuable applications for more accurate 3D vessel tracking and rendering.

• 생명과학회지
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• 제13권6호
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• pp.911-916
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• 2003

The effects of Opuntia ficus-indica (OF) administration on the biochemical parameters of function in liver tissue and serum of $CCl_4$ treated rats were investigated. Opuntia ficus-indica (200 mg/kg) was administered into rats intraperitoneally for two weeks. $3.3m\ell$ of $CCl_4$$_4$ (50% $CCl_4$ : Olive oil = 1 : 1) was treated to rats on the 14th day and 15th day and they were operated on 15th day. We examined the antioxidative enzymatic activity by measuring the level of AST (Aspartate aminotransferase), ALT (Alanine aminotransferase), GSH (Glutathione reduced form), GSSG (Glutathione oxidezed form), GPx (GSH-peroxidase), SOD (Superoxide dismutase) and CAT (Catalase) in serum and liver tissue of rats. OFC administered group showed 24.8% of inhibitory effect in AST activity compared to $CCl_4$ -treated abnormal group (CTA). ALT level of OF administered group was decreased by 60.7% to the level of CTA. GSH, GSSG and GPx of OFC administered group were significantly higher than those of CTA group. SOD and CAT in OFC administered group were increased by 28.3% and by 16.9% respectively compared to those of CTA group.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.241.1-241.1
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• 2013

최근 고집적화된 금속-산화막 반도체 metal oxide semiconductor (MOS) 소자는 크기가 점점 작아짐에 따라 얇은 산화막과 다양한 High-K 물질과 전극에 대하여 연구되고 있다. 이러한 소자의 열적 안정성과 균일성을 얻기 위해 다양한 열처리 방법이 사용되고 있으며, 일반적인 열처리 방법으로는 conventional thermal annealing (CTA)과 rapid thermal annealing (RTA)이 많이 이용되고 있다. 본 실험에서는 microwave radiation에 의한 열처리로 소자의 특성을 개선시킬 수 있다는 사실을 확인하였고, 상대적으로 $100^{\circ}C$ 이하의 저온에서도 공정이 이루어지기 때문에 열에 의한 소자 특성의 열화를 억제할 수 있으며, 또한 짧은 처리 시간 및 공정의 단순화로 비용을 효과적으로 절감할 수 있다. 본 실험에서는 metal-oxide-silicon (MOS) 구조의 capacitor를 제작한 다음, 기존의 CTA나 RTA 처리가 아닌 microwave radiation을 실시하여 MOS capacitor의 전기적인 특성에 미치는 microwave radiation 효과를 평가하였다. 본 실험은 p-type Si 기판에 wet oxidation으로 300 nm 성장된 SiO2 산화막 위에 titanium/aluminium (Ti/Al) 금속 전극을 E-beam evaporator로 형성하여 capacitance-voltage (C-V) 특성 및 current-voltage (I-V) 특성을 평가하였다. 그 결과, microwave 처리를 통해 flat band voltage와 hysteresis 등이 개선되는 것을 확인하였고, microwave radiation 파워와 처리 시간을 최적화하였다. 또한 일반적인 CTA 열처리 소자와 비교하여 유사한 전기적 특성을 확인하였다. 이와 같은 microwave radiation 처리는 매우 낮은 온도에서 공정이 이루어짐에도 불구하고 시료 내에서의 microwave 에너지의 흡수가 CTA나 RTA 공정에서의 열에너지 흡수보다 훨씬 효율적으로 이루어지며, 결과적으로 산화막과 실리콘 기판의 계면 특성 개선에 매우 효과적이라는 것을 나타낸다. 따라서, microwave radiation 처리는 향후 저온공정을 요구하는 nano-scale MOSFET의 제작 및 저온 공정이 필수적인 display 소자 제작의 해결책으로 기대한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.206.1-206.1
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• 2015

최근에 금속산화물을 증착하는 방법으로 용액공정이 주목 받고 있다. 용액 공정은 대기압에서 매우 간단한 방법으로 복잡한 공정과정을 요구하지 않기 때문에 박막을 경제적으로 간단하게 형성할 수 있다. 하지만 용액공정을 통해 형성한 박막에는 소자의 특성을 열화 시키는 solvent와 탄소계열의 불순물을 많이 포함하고 있어 고온의 열처리가 필수적이다. 박막의 품질을 향상시키기 위해서 다양한 열처리 방법들이 이용되고 있으며, 일반적인 열처리 방법으로는 furnace를 이용한 conventional thermal annealing (CTA)이 많이 이용되고 있다. 하지만, 최근에는 microwave를 이용한 공정이 주목 받고 있다. Microwave energy는 CTA보다 효과적으로 비교적 낮은 온도에서 높은 열처리 효과를 나타낸다. 본 실험은 n-type Silicon 기판에 solution-ZrO2 산화막을 형성 후, oven baking을 한 뒤, CTA와 microwave를 이용하여 solvent와 불순물을 제거 하였다. 전기적 특성을 확인하기 위해 solution ZrO2 산화막 위에 E-beam evaporator를 이용해 Ti 금속 전극을 증착하여 Metal-Oxide-Semiconductor (MOS) capacitor를 제작하였다. 다음으로, PRECISION SEMICONDUCTOR PARAMETER ANALYZER (4156B)를 이용하여, capacitance-voltage (C-V) 특성 및 current-voltage (I-V) 특성을 비교하였다. 다음으로, CTA를 통하여 제작한 소자와 전기적 특성을 비교하였다. 그 결과, Microwave irradiation으로 열처리한 MOS capacitor 소자에서 capacitance 값과 flat band voltage, hysteresis 등이 개선되는 효과를 확인하였다. Microwave irradiation 열처리는 100oC 미만의 온도에서 공정이 이루어짐에도 불구하고 시료 내에서의 microwave 에너지의 흡수가 CTA 공정에서의 열에너지 흡수보다 훨씬 효율적으로 이루어지며, 결과적으로 ZrO2 용액의 불순물과 solvent를 낮은 온도에서 제거하여 고품질 박막 형성에 매우 효과적이라는 것을 나타낸다. 따라서, microwave irradiation 열처리 방법은 비정질 산화막이 포함되는 박막 transistor 소자 제작에 대하여 결정적인 열처리 방법이 될 것으로 기대한다.

• Journal of Korean Neurosurgical Society
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• 제56권2호
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• pp.86-90
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• 2014

Objective : The spot sign is related with the risk of hematoma expansion in spontaneous intracerebral hemorrhage (ICH). However, not all spot sign positive patients undergo hematoma expansion. Thus, the present study investigates the specific factors enhancing the spot sign positivity in predicting hematoma expansion. Methods : We retrospectively studied 316 consecutive patients who presented between March 2009 to March 2011 with primary ICH and whose initial computed tomography brain angiography (CTA) was performed at our Emergency Department. Of these patients, 47 primary ICH patients presented spot signs in their CTA. We classified these 47 patients into two groups based on the presence of hematoma expansion then analyzed them with the following factors : gender, age, initial systolic blood pressure, history of anti-platelet therapy, volume and location of hematoma, time interval from symptom onset to initial CTA, spot sign number, axial dimension, and Hounsfield Unit (HU) of spot signs. Results : Of the 47 spot sign positive patients, hematoma expansion occurred in 26 patients (55.3%) while the remaining 21 (44.7%) showed no expansion. The time intervals from symptom onset to initial CTA were $2.42{\pm}1.24$ hours and $3.69{\pm}2.57$ hours for expansion and no expansion, respectively (p=0.031). The HU of spot signs were $192.12{\pm}45.97$ and $151.10{\pm}25.14$ for expansion and no expansion, respectively (p=0.001). Conclusions : The conditions of shorter time from symptom onset to initial CTA and higher HU of spot signs are the emphasizing factors for predicting hematoma expansion in spot sign positive patients.

• Journal of Korean Neurosurgical Society
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• 제42권1호
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• pp.35-41
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• 2007

Objective : Determining the location of paraclinoid aneurysms for microsurgery is important for selecting treatment options, especially when deciding on the release of the dural ring in direct clipping. We examined the reliability of using the optic strut as an anatomical landmark for evaluating the location of paraclinoid aneurysms. Methods : Cadaveric dissection was performed to establish the relationship of the optic strut to the dural ring. Results from these anatomic studies were compared with the three-demensional computed tomographic angiographic [3D-CTA] findings of nine patients with ten paraclinoid aneurysms between May 2004 and October 2005. These, 3D-CTA results were then compared with intraoperative findings. Results : The inferior boundary of the optic strut accurately localized the point at the proximal dural ring in cadaveric study. The optic strut and its relationship to the aneurysms was well observed on the multiplanar reformats of 3D-CTA. During microsurgery, nine of ten aneurysms were verified to arise from distal to the upper surface of the optic strut. Two aneurysms that had arisen between the inferior and superior boundary of the optic strut were observed to lie within the carotid cave. One aneurysm which had arisen at the inferior boundary of the optic strut and directed inferiorly was observed to lie within the cavernous sinus just after the release of the proximal ring. Conclusion : The optic strut, as identified with multiplanar reformats of 3D-CTA, provided a reliable anatomic landmark for the proximal rings and an important information about the location of aneurysms around the anterior clinoid process (ACP). Therefore, 3D-CTA and the optic strut could become an invaluable tool and a landmark in the assessment of the location of paraclinoid aneurysms for microsurgery.