• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.6
• /
• pp.867-878
• /
• 2018

As the era of AVs (Automated Vehicles) comes to a close, many researches related to AVs have been conducted. Up until now, research on traffic flow impact of AVs has been the main topic, and research on traffic management for AVs is still in beginning stage. This study analyzed the effect of Dynamic Merge Control (DMC) in manual vehicle (MV) and AV environment at work zone. Dynamic Late Merge (DLM) and DLM with Dynamic Early Merge (DEM) are compared by simulation. Simulation results showed that DLM improves travel time and work zone throughput compared to no merge control case in both MV and AV environment. In the case of additional operation of DEM, the improvement effect was not observed in MV environment, but it was improved in AV environment. As a result, DMC operation in AV environment was as effective as the improvement in transition from MV to AV environment. Therefore congestion reduction at freeway work zone by DMC will be possible in future AV environment, and the improvement of DMC can be suggested.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.22 no.1
• /
• pp.311-326
• /
• 2023

This paper proposes a plan to improve the installation and operation of traffic safety facilities using a microscopic simulation by confirming the difference in the perception method and range of autonomous vehicles and human vehicles. In this study, the existing 『Traffic Safety Sign Installation·Management Guidelines』 was reviewed, and safety signs among traffic safety facilities were classified according to changes in vehicle behavior. Subsequently, for the classified facilities, the installation location of the traffic sign was changed through simulation experiments, and the optimal location was inferred to suggest an improvement plan. This study confirmed how traffic safety facilities installed based on the visibility of human drivers affect road efficiency and safety in mixed traffic flow with autonomous vehicles and human-controlled vehicles. The optimal location derived through this study is meaningful because it can be used as the basis for revising the guidelines on the installation and management of traffic safety facilities.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.23 no.1
• /
• pp.82-96
• /
• 2024

While analyzing traffic flow, speed, traffic volume, and density are important macroscopic indicators, and acceleration and spacing are the important microscopic indicators. The speed and traffic volume can be collected with the currently installed traffic information collection devices. However, acceleration and spacing data are necessary for safety and autonomous driving but cannot be collected using the current traffic information collection devices. 'You Look Only Once'(YOLO), an object recognition technique, has excellent accuracy and real-time performance and is used in various fields, including the transportation field. In this study, to measure acceleration and spacing using YOLO, we developed a model that measures acceleration and spacing through changes in vehicle speed at each interval and the differences in the travel time between vehicles by setting the measurement intervals closely. It was confirmed that the range of acceleration and spacing is different depending on the traffic characteristics of each point, and a comparative analysis was performed according to the reference distance and screen angle to secure the measurement rate. The measurement interval was 20m, and the closer the angle was to a right angle, the higher the measurement rate. These results will contribute to the analysis of safety by intersection and the domestic vehicle behavior model.

• Journal of the Korean Society of Radiology
• /
• v.81 no.4
• /
• pp.912-919
• /
• 2020

Purpose This study aimed to compare the brain perfusion status of patients with chronic kidney disease to a normal control group to identify any significant differences. Materials and Methods The perfusion state of the brain was measured by MRI using the arterial spin labeling technique in 36 patients undergoing hemodialysis due to chronic kidney disease and 36 normal controls. Images were then analyzed in a voxel-wise manner to detect brain areas showing significant perfusion differences between the two groups. Results Patients with chronic kidney disease showed increased perfusion in the form of large clusters across the right fronto-parieto-temporal lobe and the left parieto-occipital lobe. In addition, perfusion increased in the bilateral thalami, midbrain, pons, and cerebellum (p < 0.01, familywise error corrected). Conclusion Brain perfusion appears to increase in patients with chronic kidney disease compared to normal controls. Uremic toxicity is thought to be the cause of this increase as it can cause damage to the microscopic blood vessels and their surrounding structures.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.28 no.2
• /
• pp.95-110
• /
• 2006

The treatment for oral and maxillofacial carcinoma with chemotherapeutic agents is evaluated by many effective methods to reduce the tumor mass and cancer cell proliferation. However these chemotherapy have many serious side effects, such as bone marrow suppression, renal toxicity, G-I troubles. Therefore a possible approach to develop a clinically applicable chemotherapeutic agent is to screen anticancer activity of Taxol which is known to have very little side effect and have been used to breast cancer and ovarian carcinoma. Taxol is a new anti-microtubular anti-cancer agent extracted from the bark of the Pacific yew, Taxus brevifolia. Paclitaxel(Taxol) acts by promoting tubulin polymerization and over stabilizing microtubules agianst depolymerization. Despite the constant improvements of methods of the cancer treatment especially chemotherapy, the rate of cancer metastasis and recurrent are not decreased. Thus the investigation of new drug which have very little side effect and a possible clinically application continues to be a high priority. Considering that the Taxol have shown very effective chemotherapeutic agent with relatively low toxicity in many solid tumors, it deserves to evaluate its efficacy in oral squamous cell carcinoma. In this study, to investigate the in-vivo and in-vitro anti-cancer efficacy of Taxol in oral squamous cell carcinoma and lastly, the potency of Paclitaxel in the clinical application for oral cancer was evaluated. In vivo study, after HN22 cell line were xenografted in nude mice, the growth of tumor mass was observed, 3 mg/Kg taxol was injected intraperitoneally into nude mice containing tumor mass. The methods of these study were measurement of total volume of tumor mass, histopathologic study, immunohistochemical study, drug resistance assay, growth curve, MTT assay, flow cytometry, cDNA microarray in vivo and in vitro. The results were obtained as following. 1. The visual inspection of the experimental group showed that the volume of the tumor mass was slightly decreased but no significant difference with control group. 2. Ki-67 index was decreased at weeks 4 in experimental group. 3. Microscopic view of the xenografted tumor mass showed well differentiated squamous cell carcinoma and after Taxol injection, some necrotic tissue was seen weeks 4. 4. The growth curve of the tumor cells were decreased after 1day Taxol treatment. 5. According to the MTT assay, HN22 cell line showed relative drug resistancy above $5\;{\mu}g/ml$ concentrations of Taxol. 6. In drug resistance assay, the decrease of cell counts was seen relatively according to concentration. 7. In Flow cytometry, G2M phase cell arrests were seen in low concentration of the Taxol, while S phase cell arrests were seen in high concentration of the Taxol. 8. Using cDNA microarray technique, variable gene expression of ANGPTL4, TXNRD1, FAS, RRAGA, CTGF, CYCLINEA, P19, DUSP5, CEBPG, BTG1 were detacted in the oral squamous cell carcinoma cell after taxol treatment. In this study paclitaxel is effective against oral squamous cell carcinoma cell lines in vitro, but week effect was observed in vivo. So we need continuous study about anticancer effect of taxol in vivo in oral squamous cell carcinoma.

• Journal of Life Science
• /
• v.20 no.5
• /
• pp.710-716
• /
• 2010

This study was conducted to investigate the effect of Makgeolli (MG) and Makgeolli GiGemi (MGG) on blood flow, serum lipid improvement in vivo, and inhibition of angiotensin converting enzyme (ACE) in vitro. The activities of serum AST and ALT were increased by ovariectomy. Serum AST levels were decreased to $77.71{\pm}13.97$ and $74.57{\pm}14.90\;unit/ml$ in the OVX-MG50 and OVX-MGG50 groups compared to the OVX-control group ($91.14{\pm}12.02\;unit/ml$). Serum ALT levels were decreased to $34.00{\pm}8.41$ and $30.43{\pm}3.60\;unit/ml$ in OVX-MG50 and OVX-MGG50 groups compared to the OVX-control group ($37.14{\pm}5.40\;unit/ml$). Serum total cholesterol and triglyceride contents decreased in the sham group compared with OVX-control group by ovariectomy. Six weeks feeding of MG and MGG resulted in a decrease to $116.14{\pm}36.02$ and $109.14{\pm}11.55\;mg/dl$ compared to the OVX-control group ($120.43{\pm}8.36\;mg/dl$) in serum total cholesterol, and triglyceride levels were decreased to $52.43{\pm}12.41$ and $47.29{\pm}12.08\;mg/dl$ in the OVX-MG50 and OVX-MGG50 groups compared to the OVX-control group ($58.57{\pm}5.47\;mg/dl$). The level of HDL-cholesterol in the OVX-control group was significantly reduced to $51.29{\pm}20.49\;mg/dl$ compared to the sham group ($72.29{\pm}10.29\;mg/dl$), but it was increased to $70.71{\pm}19.53$ and $62.00{\pm}20.20\;mg/dl$ with MG and MGG supplementation. Furthermore, the effect of the MG group was higher than the MGG group. Microscopic observation showed that whole blood passed smoothly through the micro channels in the MG and MGG supplemented groups. The platelet aggregation ability of the groups treated with MG and MGG was less than that of the OVX-control group. In vitro assay, the angiotensin converting enzyme (ACE) activity was significantly inhibited by MG and MGG (82.6% and 68.9% inhibition at 0.4 g/ml). These results suggest that the beneficial effects of MG and MGG may be used to improve on the lipid metabolic syndrome of menopausal women. In addition, MG and MGG might improve blood homeostasis mediated activities via antiplatelets and MG and MGG may be used as antihypertensive functional foods and nutraceuticals.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.4
• /
• pp.414-419
• /
• 2005

This study was performed to compare the treatment efficiencies of two media, newly developed Bio-rock and conventional gravel, in soil clothing contact oxidation process. The composition of synthetic wastewater were $COD_{Cr}$ $150{\sim}370\;mg/L$, $BOD_5$ $150{\sim}270\;mg/L$, T-N $20{\sim}60\;mg/L$, T-P $5{\sim}25\;mg/L$, pH 7 and 2 mL/L of trace element solution. The experiment using two reactors was comparatively conducted for the flow rate of 40 L/d for 13 months, respectively. Initially Bio-rock reactor was increased to pH 12 due to $Ca(OH)_2$ with hydration of cement, but gravel reactor was dropped to pH 4 due to the degradation of organic material and nitrification. This significant pH variation deteriorated the growth and activity of microorganism. But the high pH of Bio-rock seems favorite to ammonia stripping and precipitation of phosphate. Such pH variation of Bio-rock and gravel reactors were finally stabilized to pH 8 and pH 6, respectively. The removal efficiencies of organic compounds from Bio-rock reactor were 96% of $COD_{Cr}$, 98% of $BOD_5$, 80% of T-N and 85% of T-P which stably coping against variation of influent concentration. But those of gravel reactor were 96% of $COD_{Cr}$, 96% of $BOD_5$, 42% of T-N and 40% of T-P, respectively. The Bio-rock was 2 times higher than T-N and T-P in treatment efficiency. And electron-microscopic examination showed that Bio-rock was more favorable to microbial adherence than gravel. The microbial populations were $5.2{\times}10^6\;CFU/mL$ of Bio-rock reactor compared to $2.6{\times}10^6\;CFU/mL$ in gravel reactor. In result Bio-rock was favor to microbial adherence and high treatment efficiency in spite of variation of influent concentration which had the advantages in saving running time and reducing site requirement.

• Journal of Chest Surgery
• /
• v.36 no.2
• /
• pp.63-72
• /
• 2003

Although a variety of synthetic vascular grafts are available in modern vascular surgery, no ideal prosthesis ha,4 yet been developed. Small-caliber vascular grafts with low flow, as used in the lower extremity, continue to become thrombosed at unacceptable rates. We have developed and evaluated the new antithrombogenic blood contacting surfaces in canine model. Material and Method: Two now antithrombogenic blood contacting surfaces(Polyvinylalcohol -Polyurethane(PVA-PU) blend and natural Graphite-polyurethane(G-PU) blend) have been developed and evaluated in canine model, using vascular grafts and patches. The luminal surfaces of the test vascular grafts(5 mm ID) were fabricated by dipping a glass rod in PVA-PU blend solution(50 % PVA) using phase separation method. Mongrel dogs of either sex weighing 18-22 kg were anesthetized by endotracheal intubation using halothane and their lungs were ventilated with a volume-cycled ventilator, Maintenance anesthesia with 0.5-1.0% halothane and supplemental oxygen was used. Two pairs were used for comparison in the bilateral femoral arteries for both vascular grafts(PVA-PU vs. PU) and vascular patches(G-PU vs. PU). Bilateral groin incisions were made and the arteries were exposed and clamped. After an excision of 1 cm of the artery between clamps, a grail of 2.5 cm in length was implanted end-to-end using 6-0 polypropylene suture. The vascular patch was implanted as a form of on-lay patch. Animals were sacrificed at 1, 2, 4, 6, 8 and 16 weeks for vascular grafts and 1, 2. 4 and 6 weeks for vascular patches. Result The vascular grafts of PVA-PU blends showed patent lumina in the 2 and 16 weeks animals, while those of PU showed a patent lumen in 2 weeks animal. PVA-PU graft of 16 weeks showed a fairly clean luminal surface. A light microscopic finding of this graft demonstrated good tissue infiltration through porosity, The animals with vascular patches showed patent arteries in both groups except 2 weeks animal. Scanning electron microscopy of the luminal surfaces of G-PU patches in 4 and 6 weeks animals showed endothelial cell covering with microvilli. PU patches showed qualitatively less endothelial cell covering. Conclusion: In conclusion, PVA-PU and G-PU blends can be a promising blood contacting surfaces for application in a synthetic vascualr graft. However, further animal study is needed to determine the real long-term effects of these methods of surface modifications.

• Journal of Oral Medicine and Pain
• /
• v.38 no.2
• /
• pp.121-136
• /
• 2013

It has been known that saliva may affect the most of oral diseases. On the contrary, several systemic conditions may affect salivary flow and cause oral dryness and psychosocial stress especially may a crucial role in the etiology of hyposalivation and oral dryness. Many studies have focused on macroscopic effects of the stress on the salivary glands by autonomic response, but on the other hand it has hardly been reported on cellular microscopic effects of the stress on the salivary glands. Therefore, this study was performed to examine clusterin, a antiapoptotic and cytoprotective protein, in the parotid glands under restraint stress condition. For this study, 18 rats were divided into 3 groups; 1) 2 rats of group I were selected as a normal control. 2) 2 rats of group II, as a experimental control were placed in the restraint cone for 2 hours 3) 14 rats of group III were placed in the restraint cone for 2 hours once a day. The rats were sacrificed immediately(group II, as a experimental control), 1, 2, 3, 4, 5, 6 and 7 days after application of the stress and the both parotid glands were excised. Immunohistochemistry and electron microscopy were performed. The finding were as follows: 1. In parotid glands, repeated stress denaturalize the acinar cells, interacinous tissues and interacinous connective tissues were separated to individual acinar cells. After 4 days of experiment, there were lots of vacuoles and intercalated ducts. 2. In parotid glands, repeated stress make the rER which is in acinar cells swollen after 3 days of experiment and it was intensified to 4 days. After 5 days of experiment the edema got worse and degenerated. 3. In parotid glands, clusterin was reduced in ductal cell cytoplasm but in intercalated duct clusterin was slightly stained until 3 days prominently increased until 4 days and then decreased again after 5 days of experiment.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.21 no.2
• /
• pp.89-109
• /
• 1999

Vascular spasm which has been reported to occur in 25% of clinical cases continues to be a problem in microvascular surgery; When prolonged and not corrected, it can lead to low flow, thrombosis, and replant or free flap failure. Ischemia, intimal damage, acidosis and hypovolemia have been implicated as contributors to the vascular spasm. Although much work has been done on the etiology and prevention of vasospasm, a spasmolytic agent capable of firmly protecting against or reversing vasospasm has not been found. Therefore vascular freezing was introduced as a new safe method that immediately and permanently relieves the vasospasm and can be applied to microsurgical transfers. Cryosurgery can be defined as the deliberate destruction of diseased tissue or relief the vascular spasm in microvascular surgery by freezing in a controlled manner. 96 Sprague Dawley rats each weighing within 250g were used and divided into 2 group, experimental 1 and 2 group. In the experimental 1 group, right epigastric vessels (artery and vein) were freezed with a cryoprobe using $N_2O$ gas for 1 min. In the experimental 2 group, after freezing for 1 min, thawing for 30 secs and repeat freezing for 30 secs. Left side was chosen as control group in both group. We sacrified the experimental animals by 1 day, 3 days, 1 week, 2 weeks, 4 weeks & 5 months and observed the sequential change that occur during regeneration of epigastric vessels using a histologic, histomorphometric, immunohistochemical and SEM study after the vascular freezing. The results were as follows1. In epigastric arteries, internal diameters had statistically significant enlargement in 1 day, 3 days of Exp-1 group and 1 day, 3 days, 1 week & 2 weeks of Exp-2 group. Wall thickness had statistically significant thinning in 2 weeks of Exp-2 group. 2. In epigastric veins, internal diameters had enlargement of statistical significance in 1 day of Exp-1 and Exp-2 group. 3. The positive PCNA reactions in smooth muscle appeared in 1 week and increased until 2 weeks, decreased in 4 weeks. There was no statistical significance between Exp-1 and Exp-2 group. 4. The positive ${\alpha}$-SMA reaction in smooth muscles showed weak responses until 1 week and slowly increased in 2 weeks and showed almost control level in 4 weeks. 5. The positive S-100 reactions in the perivascular nerve bundles showed markedly decrease in 1 day, 3 days and increased after 1 week and showed almost control level in 4 weeks. Exp-1 group had stronger response than Exp-2 group. 6. In SEM, we observed defoliation of endothelial cell and flattening of vessel wall. Exp-2 group is more destroyed and healing was slower than Exp-1 group. To sum up, relief of vasospasm (vasodilatation) by freezing with cryoprobe was originated from the damage of smooth muscle layer and perivascular nerve bundle and the enlargement of internal diameter in vessels was similar to expeimental groups, but Exp-2 group had slower healing course and therefore vessel freezing in microsurgery can be clinically used, but repeat freezing time needs to be studied further.