• Restorative Dentistry and Endodontics
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• v.14 no.2
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• pp.49-64
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• 1989

The purpose of this study was to evaluate the effect of several materials on the healing process of apical wound. Sixteen mandibular premolars obtained from 4 healthy dogs were used for this study. Under general anesthesia, the pulpal chamber of each tooth was opened and the pulps were extirpated. The root canals were then instrumented with H-file and irrigated with physiologic saline solution ; the apices were purposely perforated and enlarged with the engine K-reamer. In the experimental groups, apical wounds were filled with one of calcium hydroxide, hydroxylapatite, and tricalcium phosphate materials, mixture of each materials and physiologic saline solution, with a lentulo spiral. In the control group, apical wounds were not filled with any material. All the root canals were filled by the lateral condensation technique with gutta-percha cone and ZOE sealer. The access opening of all the teeth were closed with amalgam. On the 10, 20, 40 and 60th day after experiment, experimental animals were sacrificed. Segments of jaws, each containing one tooth, were fixed in 10% formalin solution and decalcified in Plank-Rychlo solution. The specimens were embedded in paraffin and serially sectioned to an average thickness of $6{\mu}m$. The sections were stained by hematoxylin-eosin and Masson's trichrome stain method and examined under light microscope. The results were as follows : 1. In the experimental groups, the new bone formations were observed in apical wounds. 2. Fourty days later, apical wounds were healed by granulation tissue in the experimental groups, but were not healed by granulation tissue in the control group, and the healing process of experimental groups were more rapid than that of control group. 3. Sixty days later, chronic inflammation disappeared in the experimental groups, and the materials used showed biologic affinity to the periapical tissue. 4. In all the groups, the resorption of cementum appeared on the 10th and 20th day after experiment, and the deposition of cementum appeared on the 40th and 60th day after experiment, especially showing narrowness of apical foramen due to newly formed cementum in calcium hydroxide group. 5. Calcum hydroxide and tricalcium phosphate particles were gradually resolved, but hydroxylapatite particles were not resolved through the experimental period.

• The korean journal of orthodontics
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• v.50 no.1
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• pp.42-51
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• 2020

Objective: The objective of this study was to evaluate the effects of cetirizine, a histamine 1 receptor antagonist, on bone remodeling after calvarial suture expansion. Methods: Sixty male Sprague-Dawley rats were divided into 4 groups; the phosphate-buffered saline (PBS)-injected no expansion group, cetirizine-injected no expansion group, PBS-injected expansion group, and cetirizine-injected expansion group, and were observed at 7, 14, and 28 days. Five rats per group were examined at each observation day. Daily injections of cetirizine or PBS were administered to the relevant groups starting 2 weeks prior to expander insertion. A rapid expander was inserted in the calvarial bone to deliver 100 cN of force to the parietal suture. The specimens were prepared for hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining. Suture opening and bone regeneration were evaluated using microcomputed tomography and bone histomorphometric analysis. Serum blood levels of osteocalcin and carboxy-terminal collagen crosslinks (CTX) were also evaluated. Results: TRAP-positive cell counts and CTX levels decreased while osteocalcin levels increased in the cetirizine-injected expansion group at observation day 28. In the expansion groups, the mineralized area gradually increased throughout the observation period. At day 28, the cetirizine-injected expansion group showed greater bone volume density, greater mineralized area, and narrower average suture width than did the PBS-injected expansion group. Conclusions: Cetirizine injection facilitated bone formation after suture expansion, mostly by suppressing osteoclastic activity. Histamine 1 receptor antagonists may aid in bone formation after calvarial suture expansion in the rat model.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.965-968
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• 2004

Now a day, the Korean National Railroad is taking new age with the opening of KTX (Korea Train Express). Korean National Railroad is planning using the GSM-r for put KTX and existing equipment to a good. GSM-R is radio communication method selected by ERTMS (European Rail Traffic Management System). So a new algorithm for train movement is necessary to radio communication form. This paper is come up with an algorithm for like that situation.

• Management & Information Systems Review
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• v.9
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• pp.117-137
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• 2002

As attention to the Internet from both companies and individuals is rapidly on the increase, hundreds of new websites are opening in a single day. Along with such a high attention to the Internet, to set up an effective website needs efficient evaluation and reliable evaluation criterions for the website. The existing homepage contests and evaluation models are limited to certain websites in a special field or to the systemic side and to the contents, which in fact weakened the development of detailed evaluation sections and items possibly measured. This study is designed to integrate and seek out methods and success factors that should be considered when a website is built up, discovering evaluation criterions and making evaluation models objectively possible to be measured. The study focused on investigation into a new measurement standard and model by considering the previous studies, in order to suggest the followings: Centering the 7 top evaluation sections by type of each website such as (1) Service, (2) Mechanism, (3) Structure & Navigation, (4) Usability, (5) Contents (6) Community, (7) Communication, the study suggests an objective and reasonable website evaluation model on a basis of common factors considered in an integral and optimum view.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.51.3-52
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• 2015

Gamma-Ray Bursts(GRBs) are the most violent event in the universe, whose detection rate is a few in a day. The spectral lag, which is commonly observed in the observed light curves of GRBs, is a difference in arrival times of the high-energy and low-energy photons. The relation between the spectral lag and the luminosity of the observed GRBs is shown to be anti-correlated in previous studies. In reported relations to date, the isotropic luminosity has been assumed. On the other hand, GRBs are likely to emit its energy through a beamed jet. In this study, we attempt to obtain the relation between the spectral lag and the collimation-corrected luminosity. We have calculated collimation-corrected luminosities and opening angles using the observed light curves taken from a database of Swift/BAT, XRT. We expect to increase its significance level by expanding a sample size compared with those previously analyzed.

• Journal of the korean society of oceanography
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• v.32 no.1
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• pp.38-45
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• 1997

To find out the changes in vertical distribution patterns over the 24-h period, a key and the first step to tackle the problem of adaptive significance of diel vertical migration (DVM), vertically stratified time series samplings with multiple opening/closing plankton samplers were done in the East Sea of Korea (Sea of Japan). Sampling was done almost every 4 h for one day period following the same water parcel in Nov. 1995 and May 1996, respectively. Resultant patterns of vertical distribution showed that some species such as most abundant taxa Metridia pacifica and Scolecithyicella minor, both Copepoda, performed DVM even in the study area of strong thermal stratification. Their patterns of DVM such as distance scales and timing of movements were not the same each other, and they were separated from other taxa in the dendrogram obtained by the cluster analyses, Most minor taxa grouped in one, however, seemed not to do DVM in the study area of strong thermal stratification. They usually preferred the warmer surface layer where the foods were probably more abundant.

• Journal of Chest Surgery
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• v.22 no.4
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• pp.661-666
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• 1989

Congenital coronary arterial fistulae are the most prevalent hemodynamically significant congenital coronary artery malformations. Definition of congenital coronary arterial fistula is a direct communication between a coronary artery and the lumen of one of the four cardiac chambers or coronary sinus or SVC, pulmonary artery or pulmonary vein close to the heart. It is often associated with additional congenital or acquired heart disease. A 49 year old male patient was admitted with the chief complaints of anginal pain and exertional dyspnea for 9 months. He was diagnosed as the right coronary arterial fistula combined with right coronary arteriosclerotic stenosis and old inferior myocardial infarction by cardiac evaluation. The right coronary arterial fistula was communicated between the just distal portion of acute marginal branch and coronary sinus. The operative procedure was as followings; after suture ligation of fistula opening in the coronary sinus under beating heart, coronary arterial bypass grafting with saphenous vein was performed at the just proximal portion of the posterior descending branch under cardiopulmonary bypass. The postoperative course was uneventful and he was discharged without anginal pain at the 8th postoperative day.

• Journal of Chest Surgery
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• v.11 no.3
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• pp.355-358
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• 1978

The esophageal hiatal hernia is a rare disease entity in children, Especially, the paraesophageal hiatal hernia is an extremely rare. We had experienced a paraesophageal hiatal hernia in 6 month old male baby. He had postprandial vomiting for 4 months. The chest P-A and right lateral X-ray films were shown a round homogenous density in posterior mediastinum. On laparotomy, we couldn`t see the stomach in operative field. We reduced the stomach through the widened esophageal hiatus and repaired hiatal opening. His operative course was uneventful and discharged on the 9th postoperative day.

• Journal of Oral Medicine and Pain
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• v.21 no.1
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• pp.25-36
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• 1996

To investigate the effect of low level laser therapy, the author selected 37 dental students with tender points in both masseters and trapeziuses, also measured maximum comportable opening(MCO), Numerical analog scale(NAS) and pressure pain threshold (PPT). 20 subjects were assigned randomly and were treated with GaAlAs diode laser after ultrasound. The other 17 subjects were treated with ultrasound and laser without irradiation. All the subjects were treated after 2 and 4 day respectively and were examined again after 6 days. And the obtained results were as follows : 1. The MCO of irradiated group increased more significantly after treatment than non-irradiated group. 2. The NAS of irradiated group decreased more significantly after treatment than non-irradiated group. 3. The PPT or irradiated group increased more significantly after treatment than non-irradiated group.

• Journal of Chest Surgery
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• v.13 no.2
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• pp.130-133
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• 1980

Since the first report of an operation for prolapsed intervertebral disk by Mixter and Barr[1934], many thousands of operations have been successfully performed without incident. Linton and White in 1945 reported the vascular complication, but perforation of large vessels is rare complication of operation for prolapsed disk. A medical student, aged 22 years, was performed to a disk operation [L4-5, Rt. on May 1977.] From postoperative 10th day, palpitation, generalized edema and substernal pain were noted, and 2 months later, wide pulse pressure [70-80 mmHg], continuous bruit and thrill on the Rt. low abdomen were followed. Aortography revealed arteriovenous fistula between just proximal to abdominal aortic bifurcation and inferior vena cava. So, fistulectomy [Resection of proximal 2 cm of C.I.A., Rt, including fistula opening and end to end anastomosis] was performed on July, 77. During follow up study, remained fistula between Rt. internal lilac artery and lilac vein was found 2 months later. Re-operation [Double ligation of the Rt. internal lilac artery] was don on January 1978. Postop. results were excellent, except impossible to ejaculation.