• Journal of Magnetics
• /
• 제19권2호
• /
• pp.185-191
• /
• 2014

In this study we evaluated that flow rate changes affect the (time of flight) TOF image and contrast-enhanced (CE) in a three-dimensional TOF angiography. We used a 3.0T MR System, a nonpulsatile flow rate model. Saline was used as a fluid injected at a flow rate of 11.4 cm/sec by auto injector. The fluid signal strength, phantom body signal strength and background signal strength were measured at 1, 5, 10, 15, 20 and 25-th cross-section in the experienced images and then they were used to determine signal-to-noise ratio and contrast-to-noise ratio. The inlet, middle and outlet length were measured using coronal images obtained through the maximum intensity projection method. As a result, the length of inner cavity was 2.66 mm with no difference among the inlet, middle and outlet length. We also could know that the magnification rate is 49-55.6% in inlet part, 49-59% in middle part and 49-59% in outlet part, and so the image is generally larger than in the actual measurement. Signal-to-noise ratio and contrast-to-noise ratio were negatively correlated with the fluid velocity and so we could see that signal-to-noise ratio and contrast-to-noise ratio are reduced by faster fluid velocity. Signal-to-noise ratio was 42.2-52.5 in 5-25th section and contrast-to-noise ratio was from 34.0-46.1 also not different, but there was a difference in the 1st section. The smallest 3D TOF MRA measure was $2.51{\pm}0.12mm$ with a flow velocity of 40 cm/s. Consequently, 3D TOF MRA tests show that the faster fluid velocity decreases the signal-to-noise ratio and contrast-to-noise ratio, and basically it can be determined that 3D TOF MRA and 3D CE MRA are displayed larger than in the actual measurement.

• 한국안광학회지
• /
• 제15권2호
• /
• pp.161-167
• /
• 2010

목적: 한국 안경원 실정에 맞는 노안용 문진표를 개발함으로써 눈의 이상을 진단 및 예방하고, 보다 정확하고 신속한 노안검안에 도움이 되고자 하였다. 대상 및 방법: 다양한 문헌의 비교 검토를 통하여 노화에 따른 눈의 변화를 정리하여, 그 가운데 안광학적으로 검안에 활용될 수 있는 10가지 항목을 도출하였다. 먼저 검안과정에서 쉽게 알 수 있는 항목들과 생리학적인 변화들은 제외하고, 구두로 이상 유무와 정도를 파악할 수 있는 항목들을 먼저 도출한 후, 발생빈도가 높으며 임상에서 중요도가 높은 증상들을 중심으로 구성하였다. 결과: 10가지 노안관련 증상들을 진단할 수 있도록 15개의 문항으로 이루어진 노안용 문진표를 작성하였다. 문진표의 1번 문항은 조절력감퇴와 관련된 질문이고, 2번 문항은 굴절부등시와 연관되어 있다. 3번 문항은 안구건조증, 4번과 5번 문항은 비문증, 6번 문항은 암순응, 7번문항은 명 암순응과 관련되어 있다. 그리고 8번 문항은 대비감도, 9번 문항은 대비감도와 굴절부등시, 10번 문항은 대비감도와 색각시, 11번 문항은 시야, 12번 문항은 입체시, 13번 문항은 색각시, 14번 문항은 백내장, 15번 문항은 노안 자체와 관련된 질문이다. 각각의 문항은 이해하기 쉽고 보편적으로 일어나기 쉬운 증상들을 위주로 표현되었다. 결론: 이러한 과정을 거쳐 제작된 노안용 문진표는 노화에 따른 눈의 변화를 파악하는데 도움을 주어 한국 안경원 임상현장에서의 노안검안에 참고자료로 유익하게 활용될 수 있으리라 기대된다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제33권4호
• /
• pp.281-287
• /
• 2007

Purpose: This study was conducted in order to evaluate how chemiluminescent lighting($ViziLite^{(R)}$) could increase the sharpness of margin and contrast to normal mucosa in the diagnosis of oral lichen planus(OLP), the most frequent oral premalignant lesion, compared with direct visual inspection under incandescent light. Methods: 41 consecutive patients, diagnosed to have OLP with visual inspection under incandescent light, were further examined with chemiluminescent light. The degrees of margin sharpness and lesion contrast were ranked on a scale from 1 to 3 for all patients under visual inspection and chemiluminescent light. The presence of additional lesion only detected by chemiluminescent light, complication, and discomfort were checked for each patient. After both screening tests, biopsy specimens were harvested from all patients with scalpels and histopathologic assessments were done. Results: All 41 patients were diagnosed to have OLP by both visual inspection and chemiluminescent light examination. This result was definitively diagnosed by histopathology. Degrees of margin sharpness and lesion contrast were increased by chemiluminescent light compared with visual inspection, but only the difference of lesion contrast was statistically significant. In 22.0% of patients, additional lesions were detected and 88.9% of them were diagnosed to have OLP histopathologically. 17.1% of patients noted discomfort and 9.8% of patients showed complications after chemiluminescent test. Conclusion: Chemiluminescent light may not be proper for the screen test of oral cancer or premalignant lesion but showed some possibility for additional diagnostic tool for definitively diagnosed patients in determination of lesion margin and scope.

• 수면정신생리
• /
• 제5권2호
• /
• pp.155-169
• /
• 1998

Attentional dysfunction is considered as one of the core deficits in schizophrenic process. The findings, pathophysiological mechanisms, and their clinical implications of clinical and experimental neurocognitive tests for the attentional impairment in schizophrenics are reviewed. The influences of psychopathology, antipsychotic treatment, and chronic institutionalization are also included in the review. In contrast, there are only a few evidences that attentional dysfunction would be a core deficit of depressive, manic, and anxiety disorders. Some recent findings of attentional impairment in these disorders are reviewed.

• 영어어문교육
• /
• 제12권1호
• /
• pp.183-204
• /
• 2006

This study investigated the effects of rehearsed English drama activities on the learner variables and oral communication achievements of Korean elementary school students. Forty children in the treatment group participated in the drama activities while forty-two children in the contrast group participated in the regular classes. The results of the study are as follows: the treatment group showed significant differences between the pre-tests and the post-tests in language learning strategies, motivation, confidence, perceived competence, willingness to communicate, and listening and speaking achievements; the students in the treatment group progressed in their attitudes toward and participation in the classroom activities. Based on the findings, it is concluded that the rehearsed drama activities positively affect the learner variables and oral communication. The pedagogical implications are discussed in the conclusion.

• Toxicological Research
• /
• 제11권1호
• /
• pp.77-80
• /
• 1995

Antigenic potential of genetically-engineered human erythropoietin (EPO) was assessed in guinea pigs (active systemic anaphylaxis [ASA] ; passive cutaneous anaphylaxis [PCA]) and in vitro (hemagglutination test [PHA]). In ASA, EPO at 70~700 U/kg elicited a weak anaphylactic response tvhereas the positive control ovalbumin (OVA) did cause intensive responses leading to death in 40% animals. However, the extract of CHO cells, to which EPO gene was introduced, did not cause any symptom. In PCA and PHA tests, neither EPO nor CHO cell extract induced positive responses. OVA, in contrast, produced high titers in both PCA and PHA tests. It was concluded that, in light of the fact that EPO was slightly antigenic only in ASA but not in PCA or PHA and also that human EPO is a foreign protein to guinea pigs, the present EPO may not be antigenic in humans.

• Geomechanics and Engineering
• /
• 제12권6호
• /
• pp.899-917
• /
• 2017

Sixty four tests were performed in a steel tank to investigate the axial responses of piles driven into organic soil prepared at two different densities using a drop hammer. Four different pile materials were used: wood, steel, smooth concrete, and rough concrete, with different length to diameter ratios. The results of the load tests showed that the shaft load capacity of rough concrete piles continuously increased with pile settlement. In contrast, the others pile types reached the ultimate shaft resistance at a settlement equal to about 10% of the pile diameter. The ratios of base to shaft capacities of the piles were found to vary with the length to diameter ratio, surface roughness, and the density of the organic soil. The ultimate unit shaft resistance of the rough concrete pile was always greater than that of other piles irrespective of soil condition and pile length. However, the ultimate base resistance of all piles was approximately close to each other.

• 영어어문교육
• /
• 제15권4호
• /
• pp.95-108
• /
• 2009

One of the learning difficulties for Korean learners of English is the intonation of English focused yes/no questions. Focused words in English yes/no questions are realized as low pitch accents which contrast with high pitch accents in Korean counterparts. In order to improve Korean students' intonation, direct and metalinguistic explanations on the intonation of English focused yes/no questions were given to Korean learners of English. In pre-tests and post-tests, students' perceptions on the target items were measured. The study results showed that phonetic explanation using intonation contour enhanced students' perception on English intonation. With respect to the position of focused words, sentence initial and medial focused questions were more difficult than sentence final focused questions. The perception was most improved in sentence initial focused questions. The study showed the immediate effects of the explicit instruction on perceptions of English intonation.

• 한국세라믹학회지
• /
• 제44권9호
• /
• pp.465-470
• /
• 2007

This paper presents an experimental study of the sulfate resistance of mortars and pastes exposed to sodium sulfate solutions up to one year. In order to check deterioration modes due to sulfate attack, the sodium sulfate solution was varied at three concentration steps (3,380, 10,140 and 33,800 ppm of $SO_4^{2-}$ ions), and maintained at ambient temperature. The tests include a visual examination, expansion and compressive strength loss measurements as well as x-ray diffraction tests. The experimental data indicated that the use of cement with a low $C_3A$ content and low silicate ratio has a beneficial effect on the sulfate attack of mortars. In contrast, the mortars with a high $C_3A$ content and high silicate ratio became severely degraded due to the formation of ettringite, gypsum and/or thaumasite in the cement matrix.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2006년도 추계학술대회 논문집
• /
• pp.1380-1384
• /
• 2006

Sediments deposited on lateral drain pipes in a tunnel make lateral porous pipes clogged. Since the safety of the tunnel can be affected by this phenomenon, it requires a regular maintenance of the lateral drain pipes. In this study, a series of centrifugal tests were conducted in order to find out the method which can reduce the clogging effect considerably. Four different types of tunnel drain configurations were selected in the experiments. By analysis of sediments for each configuration, the optimum drain configuration that can minimize sedimentation of cement constituents was investigated. As a results, the existing drain configuration which uses filter concrete appear to produce much sediments. In contrast, the new drain configuration appears to be able to reduce sedimentation ratio up to almost 50% comparing with the existing one. From these observations, it may be concluded that the new drain configuration, in which the lateral porous pipes of a tunnel are surrounded by gravel layer and non-woven geotextile, has high efficiency in maintenance.