• 한국전산유체공학회:학술대회논문집
• /
• 2011.05a
• /
• pp.395-406
• /
• 2011

In this research a numerical simulation method is developed for moving body in free surface flows using fixed staggered rectangular grid system. The non-linear free surface near the body is defined by marker-density method. The body boundary is defined by line segment connecting the points where the body surface and grid line meet. Continuity equation and Navier-Stokes equations are used as governing equations and the equations are coupled with two-step projection method. The velocities and pressures of body boundary and free surface cells are calculated with simultaneous iterative method. To treat a body movement in a fixed grid system, the volume displaced by moving body is added to the divergence of the body boundary cell. For the verification of the present numerical method. vortex shedding period of advancing cylinder is calculated and the period is compared with existing experiment results. Moreover, added mass and damping coefficients of a vertically excited box are calculated and the computed results are compared with published experiment results. Impulsive pressure and water level variation due to sloshing phenomenon are simulated and the results are compared with published experiment results. Varying the plunger shape, the waves generated by plunging type wave maker are compared with the 2nd order Stokes wave theory The plunger shape generating the wave that shows the best agreement with the theory is represented.

• Applied Microscopy
• /
• v.27 no.2
• /
• pp.131-144
• /
• 1997

The present study was carried out to investigate the processes of the ultrastructural differentiation and the acetylcholinesterase (AChE) activities of the developing rat retina. The results are as follows. The retina of fetal rat on the 13th day of gestation showed the early stage of differentiation. Briefly, there appeared dividing chromosomes, the plentiful free ribosomes, and the high ratio of nucleus to cytoplasm. The reaction products by AChE were localized at the membrane of endoplasmic reticulum and on the outer membrane of nucleus. Ultrastructures and AChE activities in the retina of the fetal rats on the 18th day of gestation were similar to those of the prior stages, except the appearence of rough endoplasmic reticulum and Golgi apparatus. According to the ultrastructural observations, the rat retina was still in immature state at birth, but the pigment epithelial cells were fully differentiated, e. g. the increase of melanin granules, the development of mitochondria and Golgi apparatus. The AChE activity was weekly detected. The differentiated retinal layers and the outer segment of photoreceptor cells were observed on the 7th postnatal day. And the pigment epithelium appeared to be fully differentiated. On the 14th postnatal day, rat retina were completely differentiated. In other words, the rat retina was characterized by the prominent outer segments, phagocytosed residues in the pigment epithelium, and the localization of reaction products by AChE in the synapses. In conclusion, the differentiation of rat retina is charaterized by the changes of cell shape, the increase of retinal layers, and the alterations of AChE activities. It seems that rat retina is to be functional from 2 weeks of birth onward, coinciding with the eye opening of the juvenile rats.

• Applied Microscopy
• /
• v.24 no.2
• /
• pp.12-25
• /
• 1994

This research was undertaken to determine the effects of the anticancer and immunosuppressive drug cyclophosphamide (CP) on the epididymis of the male rat in terms of ultrastructural alteration and protein analysis by SDS-PAGE at different groups; control group, 1 week group, 3 weeks group, 5 weeks group were treated with saline (control group) or CP at doses of 20mg/Kg/week, 1 time a week, respectively. In the cytoplasm of the principal cells on the epididymis, the mitochondrial outer and inner membranes were significantly swollen or disrupted. The cisterns of rough endoplasmic reticulum (rER) were also swollen, and a number of Golgi vesicles were increased, respectively. It is suggested that treatment with CP alters the specific cell organelles in all segments of the epididymis. CP caused changes in protein concentrations in cauda of epididymis after CP treatment. Total proteins of 30 to 39 species such as lactate dehydrogenase, carnitine acetyltransferase and acid phosphatase were expressed in the cauda fluid. Then the more CP was increased, the more concentration of proteins caused to decrease, synthesize or increase in epididymal cauda. In contrast to the control group, in particular 29KD and the other 10 proteins in the cauda fluid were decreased or disappeared, respectively, whereas 89KD and the other 6 proteins in the cauda, were increased or synthesized, respectively. The other proteins are not showed distinctive difference. Therefore, it is possible that CP at a high dose accumulation alters epididymal function with dose-related increase or decrease in specific activity of marked proteins for all regions of the epididymis (particularly, specific segment of cauda). These alterations could be mediated by direct, toxic effects of the drug on the epithelium or be secondary to changes in the spermatozoa as a result of the CP treatment.

• Proceedings of the Botanical Society of Korea Conference
• /
• 1999.07a
• /
• pp.11-15
• /
• 1999

In order to evlauate feasibility of the gene tagging by the maize transposable element Ac in heterologous plant systems, we have investigated physical distances and directions of transposition of the element in Arabidopsis thaliana and tobacco cultured cell line BY-2. We prepared a T-DNA construct that carried a non-autonomous derivative of Ac with a site for cleavage by endonuclease I-Scel (designated dAc-I-RS element). Another cleavage site was also introduced into the T-DNA region outside dAc-I-RS. A number of transgenic Arabidopsis plants were generated, each of which had a single copy of the T-DNA at a different chromosomal location. To examine the pattern of transposition, three out of these transgenic plants were crossed with the Arabidopsis plant that carried the gene for Ac transposase and progeny in which dAc-I-RS had been transposed were isolated. After digestion of the genomic DNA of these progeny with I-SceI, sizes of segment of DNA were determined byd pulse-field gel electrophoresis. We also performed linkage analysis for the transposed elements and sites of mutations near the elements. Our results with three transgenic lines showed that 50% of all transposition events had occurred within 1,700 kilo-base pairs (kb) on the same chromosome, with 35% within 200 kb, and that the elements transposed in both directions on the chromosome with roughly equal probability. The data thus indicate that the Ac-Ds system is most useful for tagging of genes that are present within 200 kb of the chromosomal site of Ac in Arabidopsis. In addition, determination of the precise localization of the transposed dAc-I-RS element should definitely assist in map-based cloning of genes around insertion sites. In the present paper, we report typical examples of such gene isolation studies.

• Proceedings of the Botanical Society of Korea Conference
• /
• 1985.08b
• /
• pp.51-57
• /
• 1985

In order to evlauate feasibility of the gene tagging by the maize transposable element Ac in heterologous plant systems, we have investigated physical distances and directions of transposition of the element in Arabidopsis thaliana and tobacco cultured cell line BY-2. We prepared a T-DNA construct that carried a non-autonomous derivative of Ac with a site for cleavage by endonuclease I-Scel (designated dAc-I-RS element). Another cleavage site was also introduced into the T-DNA region outside dAc-I-RS. A number of transgenic Arabidopsis plants were generated, each of which had a single copy of the T-DNA at a different chromosomal location. To examine the pattern of transposition, three out of these transgenic plants were crossed with the Arabidopsis plant that carried the gene for Ac transposase and progeny in which dAc-I-RS had been transposed were isolated. After digestion of the genomic DNA of these progeny with I-SceI, sizes of segment of DNA were determined byd pulse-field gel electrophoresis. We also performed linkage analysis for the transposed elements and sites of mutations near the elements. Our results with three transgenic lines showed that 50% of all transposition events had occurred within 1, 700 kilo-base pairs (kb) on the same chromosome, with 35% within 200 kb, and that the elements transposed in both directions on the chromosome with roughly equal probability. The data thus indicate that the Ac-Ds system is most useful for tagging of genes that are present within 200 kb of the chromosomal site of Ac in Arabidopsis. In addition, determination of the precise localization of the transposed dAc-I-RS element should definitely assist in map-based cloning of genes around insertion sites. In the present paper, we report typical examples of such gene isolation studies.

• Tuberculosis and Respiratory Diseases
• /
• v.46 no.3
• /
• pp.432-437
• /
• 1999

Benign fibrous mesothelioma of the pleura is a relatively rare neoplasm originated from pleural mesothelial cell, often asymptomatic or presenting with a specifical sign. One of the main problems, concerns the preoperative differential diagnosis, mainly because it is difficult to differentiate between benign and malignant type. A 62-year old woman presented with recurrent chest pain. The chest radiography in a patient was suspected localized pleural mesothelioma. The chest computed tomography scan showed that mass like lesion of well marginated ovoid shape with homogenous attenuation on anterior-basal segment of right lower lobe. After resection of a pleural mass by thoracoscopic extirpation from right hemithorax, Localized benign fibrous mesothelioma of the pleura was confirmed by pathology and immunohisto-chemical staining. We report here one case of pleural benign fibrous mesothelioma with some considerations on its diagnosis and treatment.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.40
• /
• pp.32.1-32.8
• /
• 2018

Background: The free vascularized fibula flap presents many advantages such as sufficient length of the bony segment, good vascularization, better quality of the bone, and a long vascular pedicle, but it is also associated with some disadvantages with regard to prosthetic rehabilitation because of its limited height. Improvement in bone height is necessary for ideal dental implant treatment of reconstructed mandibles. Case presentation: For two squamous cell carcinoma patients, mandibular bone reconstruction was performed secondarily with the peroneal flap after tumor resection. Since the bone height was insufficient at the time of implant treatment, occlusion reconstruction by dental implant was performed after vertical distraction osteogenesis. Conclusions: Vertical distraction osteogenesis is a suitable treatment option for alveolar ridge deficiency resulting from fibula transplantation for mandibular reconstruction following tumor surgery.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2020.12a
• /
• pp.63-63
• /
• 2020

Rice stripe virus (RSV) disease is one of the major constraints in rice production, transmitted by the small brown planthopper (SBPH; Laodelphax striatellus). Upon RSV infection, plants develop typical symptoms, which include chlorosis and weakness of newly emerged leaves, white and yellow spots, stripe on leaves, and necrotic and wilting leaves, resulting in plant growth inhibition, oxidative damage that may culminate in programmed cell death (PCD) and plant death in severe epidemics. Although RSV-resistant quantitative trait loci (QTLs), Stv-a, Stv-b, and Stv-bi, were mapped using various resistant varieties, one RSV-resistant gene, OsSOT1, has been identified so far. In this study, we used the rice cultivar Zenith, known to carry Stv-b, to investigate novel RSV-genes through fine mapping. Therefore, we crossed Zenith (Donor parent, RSV resistant) with Ilpum (Recurrent parent, RSV susceptible) to fine-map using a BC₂F₂ population of 2100 plants. Chromosome segment introgression lines that were heterozygous at a different region were selected, two types of heterozygous lines showed an heterozygous genotype between Sid2 and Sid75 to Indel9 and RM6680. Interestingly, we identified qSTV11^Z region harboring Stv-b, covering about 171-kb region between the InDel markers Sid75 and Indel8. The localization of qSTV11^Z provides useful information that could be used for marker-assisted selection and determination of genetic resources in rice breeding.

• Journal of Cerebrovascular and Endovascular Neurosurgery
• /
• v.25 no.2
• /
• pp.160-174
• /
• 2023

Objective: Carotid artery stenting (CAS) is currently widely used for the treatment of carotid artery stenosis. The objective of this study was to analyze the outcomes of CAS performed in a single institution. Methods: We retrospectively analyzed 313 CAS cases from January 2007 to December 2020, including 206 (66%) symptomatic and 107 (34%) asymptomatic cases. Procedure-related morbidity and mortality were assessed. Rates of periprocedural (≤30 days after CAS) and postprocedural ipsilateral strokes (>30 days after CAS) were also assessed. Logistic regression analysis was used to identify risk factors for the periprocedural complication, in-stent restenosis (ISR), and ipsilateral stroke. Results: The success rate of CAS was 98%. Among 313 cases, 1 patient died due to hyperperfusion-related intracerebral hemorrhage (ICH). The CAS-related mortality rate was 0.31%. The overall incidence of periprocedural complications is 5.1%. A risk factor for periprocedural complication was a symptomatic carotid artery stenosis (7.3% vs. 0.9%, p=0.016). Twenty cases of ISR occurred during 63.7±42.1 months of follow-up. The overall incidence of ISR was 10.2% (20/196). A risk factors for ISR were diabetes mellitus (17.6% vs. 5.7%, p=0.008) and patients who used Open-cell stents (19.6% vs. 6.9%, p=0.010). The overall incidence of ipsilateral stroke is 5.6%. A risk factors for ipsilateral stroke was ISR (95% CI, p=0.002). Conclusions: CAS is a safe and effective procedure for carotid artery stenosis. Although the incidence of complications is low, fatal complication such as hyperperfusion-related ICH can occur. To prevent hyperperfusion-related ICH, several methods such as strict blood pressure (BP) control, intentional less widening of stenotic segment should be used. To prevent ISR or stroke occurrence, special attention should be paid to patients who have ISR or ipsilateral stroke risk factors.

• The korean journal of orthodontics
• /
• v.29 no.6 s.77
• /
• pp.673-688
• /
• 1999

This study was conducted in order to analyze the mechanical characteristics of multiloop edgewise archwire (MEAW). The purposes were 1) to compare load deflection rate (LDR) of MEAW with that of various other arch wires in the individual interbracket span, 2) to compare the wire stiffness in the interbracket span with that in the multi-L-loop region (the span from distal border of the bracket of the lateral incisor to the mesial border of the buccal tube of the second molar), and 3) to verify the experimental results with theoretically derived formula. The single L-loops of five different horizontal lengths and multi-L-loops for the upper and lower arches were made out of .$016\times.022$ permachrome stainless steel wire. Straight segment of plain stainless steel, TMA and NiTi wire of the same dimension were prepared. The LDR was measured using Instron model 4466 with the load cell of 50N capacity at cross head speed of 1.0mm/min, and maximum deflection of 1.0mm. Five specimens were tested under each experimental condition. The wire stiffness number for each interbracket region and multi-L-loop region was calculated from the LDR and the interbracket spans. By dividing the theoretical model of multi-L-loop into 35 linear segments, the energy stored in each segment was obtained. Then the LDR and wire stiffness of single L-loop and multi-L-loop were calculated and compared. The findings were as follows : 1) The average LDR of MEAW in the individual interbracket region was 1/1.53 of that of the NiTi,1/2.47 of TMA and 1/5.16 of the plain stainless steel wire. 2) The wire stiffness of MEAW in the multi-L-loop region was 1.53 times larger than that in the interbracket region, and the LDR was almost twice as large as that of NiTi in that region. 3) According to the theoretically derived equation, the wire stiffness of the single L-loop was lower than that of multi-L-loop. The results of this study suggest that MEAW has the unique mechanical Property which could allow individual tooth movement and transmit elastic force effectively through the entire arch wire.