• Restorative Dentistry and Endodontics
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• v.27 no.6
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• pp.577-586
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• 2002

The purpose of this in vitro study was to compare the effects of root canal cleanness following two Ni-Ti rotary instruments with different rake angle. Thirty-six sound, extracted human premolars with single root were randomly divided into three groups. The used rotary instruments were HEROShaper (Group 1, Micro-Mega, Besancon, France, n=12) and ProFile (Group 2, Maillefer, Ballaigues, Switzerland, n=12). Control group (n=12) was only extirpated with barbed broach (Mani, Matsutani Seisakusho Co., Japan) Group 1 & 2 teeth were prepared to a #40/.04 taper at the apex followed by 1 mm using crown-down technique. After canal preparation and frequent irrigation with 5.25% sodium hypochlorite, the roots split longitudinally into a bucco-lingual direction. Root halves were cross-sectioned in apical third portion again. All root specimens were processed for SEM investigation and photographed. Separate evaluations by one endodontist were undertaken for smear layer on prepared walls with a five score-index for each using reference photograph in root halves. The penetration depth of smear layer into dentinal tubules was also estimated in the other halves. Following results were obtained: 1. Smear layer was observed on all the prepared walls with two experimental groups except control group. 2. Smear layer characteristics in two experimental groups; 1) HEROShaper group showed snowy, dusty appearance and were shown open dentinal tubuli on the prepared walls of almost specimens, and the thickness of smear layer covering onto dentinal surfaces was within 1-2 ${\mu}m$ in a few specimens. 2) ProFile group showed shiny, burnished appearance and complete root canal wall covered by a homogenous smear layer with no open dentinal tubuli in all specimens. The penetration of smear layer into dentinal tubules was found in all specimens and the thickness was at 2-4 ${\mu}m$ in all specimens. These results demonstrated that a completely clean root canal could not be achieved regardless of positive or negative rake angle, which is in accordance with the majority of previous studies on root canal cleanliness In conclusion, through irrigation with antibacterial solutions or chelating agents is recommended to remove the smear layer on prepared canal wall in spite of Ni-Ti instrumentation.

• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.66-75
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• 2008

This study examined the influence of the apical sizes on the sealing ability of a root canal filling. Thirty-six single rooted teeth with a single canal were divided into 3 groups (n = 12) and instrumented with either the $Profile^{(R)}$ or $LightSpeed^{(R)}$ system to achieve three different apical sizes (master apical file [MAF] of #25, #40, or #60). The teeth were filled with gutta perch a using a modified continuous wave technique. The level of microleakage was determined by immersing ten teeth from each group into India ink for 1 week followed by clearing with nitric acid, ethyl-alcohol, and methylsalicylate. The microleakage was measured using vernier calipers. The data was analyzed statistically using Kruskal-Wallis one-way ANOVA and a Student-Newman-Keuls Method. Two teeth from each group were sectioned horizontally at 1, 2, 3 and 4 mm from the apex in order to observe a cross section. The apical size was significantly (p < .05) influenced the level of microleakage. In the Student-Newman-Deuls Method, MAF sizes of #25 and #40; and MAF sizes of #25 and #60, respectively showed a statistically significant difference. There was no significant difference between #40 and #60. In most cross sections, oval-shaped canals were observed, and the irregularity of the internal surface increased with decreasing apical size. There was also an increase in the area of recess, which is the area where the canal space is not filled with either gutta-percha or sealer. When the root canals are filled using a modified continuous wave technique, canal filling with more consistent and predictable outcome may be expected as the apical preparation size is increased.

• Applied Microscopy
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• v.30 no.4
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• pp.357-365
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• 2000

Paneth cells have been suggested to contribute to the elimination of excess metals into the intestinal lumen. The purpose of this study wat to investigate the changes of the zinc pools in rats subjected to functional loading with zinc salt by mean of both light and electron microscopical autometallography (AMG). Wistar rats 4 were administrated with zinc chloride (20 mg/kg body weight) intraperitoneally dissolved in 1 ml distilled water. The control group received 1 ml saline IP. After further one hour the animals were transcardially perfused with 0.4% sodium sulphide dissolved in 0.1 M PB fellowed by 3% glutaraldehyde solution for 10 minutes. Pieces of ileum were frozen with solid $CO_2$ and sectioned on a cryostat. The sections $(20{\mu}m)$ were autometallographically developed. Sections selected for EM were reembedded on top of a blank Epon block, from which ultrathin sections (100 nm) were cut. The ultrathin sections were double stained with uranyl acetate (30 min) and lead citrate (5 min), then examined under electron microscope. Studies of comparable sections from control and zinc loaded animals with the AMG selenium method gave quite different results. The control animals demonstrated a weakly positive staining in the cytoplasm of the Paneth cells. In the electron microscope the AMG silver grains were found to be located in the cytoplasm, while the electron dense secretary granules and other cell organelles were void of staining. Few AMG grains were located at the apical surface of the Paneth cells. In sections from zinc loaded rats, the AMG grains were seen in abundance in the lumen of the Lieberkuhn crypts at light microscopic levels. At EM levels the zinc revealing silver grains were located in the cytoplasm as in the controls, but much more AMG grains were shifted into the secretary granules. Furthermore, profound AMG grains were found in the lumen of the crypts and surrounding vessels. And a few grains were seen in the endothelium. The AMG technique demonstrated a pattern of AMG grains in the Paneth cells that strongly suggests a transport of zinc ions through these cells.

• Toxicological Research
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• v.4 no.1
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• pp.55-84
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• 1988

This study was carried out to investigate the teratological potential of azinphos-methyl in the rat fetuses and to establish the nature of the effects on organogenesis and intrauterine development. The Sprague-Dawley female rats (180-210g) without previous litter were used in this study. Azinphos-methyl dosages of 0.094mg/kg, 0.4mg/kg, 1.5mg/kg were selected based on the acute intragastric $LD_{50}$ of 15mg/kg in the rat. Azinphos-methyl in water (Treatment Group), non-treatment control (Negative Control), water control (Sham Control), were administered by oral route and aqueous solution of acetyl salicylic acid (Positive Control) was administered by gavage at rate of 10 ml/kg of body weight from day 6 through 15. The results obtained were summarized as follows. 1. Decreased body weight of dams was observed in animals treated with aspirin and azinphos-methyl 1.5 mg/kg from day 7 through 14. (P<0.01) 2. There was an apparent decrement in the absolute liver weight in the azinphos-methyl 1.5 mg/kg treated group (P<0.05). However, the absolute and relative kidney weight in aspirin group (P<0.05, P<0.01) and the absolute and relative ovary weight in aspirin, azinphos-methyl treatment groups (P<0.01, P<0.05) were increased. 3. Decreased protein contents of dam's liver was observed in the aspirin and high dose azinphos-methyl treated group of animals (P<0.01). 4. The number of male-female ratio per dam increased in azinphos-methyl 1.5 mg/kg group but there was an apparent decrement in the body weight of fetuses in aspirin and high dose azinphos-methyl group (P<0.01, P<0.05). Total immature and resorbed fetuses were increased in aspirin group and the number of dead fetuses were also increased in azinphos-methyl 1.5mg/kg treated group of animals. (P<0.01, P<0.05). 5. In soft tissue defects, diaphragmatic hernia in diaphragm, anophthalmia, enlarged olfactory bulb, hydrocephalus, absence of third and lateral ventricle in skull, hydronephrosis in kidney, atrophy of left ventricle wall, enlarged apex in heart were observed. Especially, defects of diaphragm, heart and eye ball showed peak incidences in the high dose azinphosmethyl and aspirin group. (P<0.01). 6. Variations in the ossification patterns of skull, sternebrae, tail, forelimbs and hindlimbs showed peak incidences in the aspirin and high dose azinphos-methyl group. (P<0.01). 7. In the developmental indices of offspring, the mortality of aspirin and azinphos-methyl 1.5mg/kg treated group was higher than that of negative control. And, there was an apparent decrement in the body weight of fetuses (P<0.01) and considerable differences were obtained in pivoting, development of fur, auditory function, vision, quadrupled muscle development and testes descent in aspirin and azinphos-methyl 1.5mg/kg group. (P<0.01).

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.151-161
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• 1991

I tried to specify the taxa of Fagaceae in Korea by the character of their pollen grains. The light microscope(LM) and the Scanning electron microscope(SEM) were used to examine the pollen grains of 19 taxa, 5 genera. The result are as follows. 1. The pollen of Fagaceae in Korea could be grouped into four types and 4 subtypes. 1) Fagus type 2) Castanea type 3) Lithocarpus, Castanopsis type 4) Quercus type (1) Cyclobalanopsis subtype (2) Prinus subtype (3) Dentatae subtype (4) Cerris subtype. 2. The morphology of the granula on the pollen of Quercus was closely related to the differantiation of the shape of the cup scales. 1) The uniformity of branching granula on the pollen grain surface corresponds to the morphological features of the concentric arrangement of cup scales. 2) The morphological features of the pollen grain surface intermingled with large or small granula, simple-granula and tuber granula which have small points of circular prominence, corresponded to those of short cup scales. 3) The morphological features of the polllen grain surface intermingled with large or small granula, simple-granula and tuber granula with an apex of amoeba type corresponded to those of Q. dentata Thunb, with thin, fine and long cup scales. 4) The morphological features of the pollen grain surface intermingled with large of small granula of with only simple-granula, corresponded to those of Q. acutissima carr. with thick, fine and long cup scales. 3. The result of cluster analysis by coding the sculpture pattern of the pollen grain surface, the existence and nonexistence of surface perforate, the grain size and granula type were coincident with the system of classification of plants and showed an intimated relationship even under th level of species.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.194-200
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• 2007

Purpose: $^{13}N$-ammonia is a well known radiopharmaceutical for the measurement of a myocardial blood flow (MBF) non-invasively using PET-CT. In this study, we investigated a correlation between MBF obtained from dynamic imaging and myocardial perfusion score (MPS) obtained from static imaging for usefulness of cardiac PET study. Methods: Twelve patients (11 males, 1 female, $57.9{\pm}8.6$ years old) with suspicious coronary artery disease underwent PET-CT scan. Dynamic scans (6 min: $5\;sec\;{\times}\;12,\;10\;sec\;{\times}\;6,\;20\;sec\;{\times}\;3,\;and\;30\;sec\;{\times}\;6$) were initiated simultaneously with bolus injection of 11 MBq/kg $^{13}N-ammonia$ to acquire rest and stress image. Gating image was acquired during 13 minutes continuously. Nine-segment model (4 basal walls, 4 mid walls, and apex) was used for a measurement of MBF. Time activity curve of input function and myocardium was extracted from ROI methods in 9 regions for quantification. The MPS were evaluated using quantitative analysis software. To compare between 20-segment model and 9-segment model, 6 basal segments were excluded and averaged segmental scores were used. Results: There are weak correlation between MBF (rest, 0.18-2.38 ml/min/g; stress, 0.40-4.95 ml/min/g) and MPS (rest 22-91%, stress, 14-90%), however the correlation coefficient between corrected MBF and MPS in rest state was higher than stress state (rest r=0.59; stress r=0.80). As a thickening increased, correlation between MBF and MPS also showed good correlation at each segments. Conclusions: Corrected and translated MPS as its characteristics using $^{13}N$-ammonia showed good correlation with absolute MBF measured by dynamic image in this study. Therefore, we showed MPS is one of good indices which reflect MBF. We anticipate PET-CT could be used as useful tool for evaluation of myocardial function in nuclear cardiac study.

• Radiation Oncology Journal
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• v.25 no.1
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• pp.26-33
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• 2007

[ $\underline{Purpose}$ ]: The aim of this study is to evaluate and compare the incidence and aspects of myocardial perfusion defects in patients who were subjected to either two-dimensional or three-dimensional simulation techniques for early left-sided breast cancer. The myocardial perfusion defects were determined from using single photon emitted computerized tomography (SPECT) myocardial perfusion images. $\underline{Materials\;and\;Methods}$: Between January 2002 and August 2003, 32 patients were enrolled in this study. The patients were diagnosed as having early (AJCC stage T1-T2N0M0) left-sided breast cancer and were treated with tangential irradiation after breast-conserving surgery and systemic chemotherapy. The patients were divided into two groups according to the type of simulation received: two-dimensional simulation using an X-ray fluoroscope simulator or three-dimensional simulation with a CT simulator. All patients underwent technetium-99m-sestamibi gated perfusion SPECT at least 3 years after radiotherapy. The incidence and area of myocardial perfusion defects were evaluated and were compared in the two groups, and at the same time left ventricular ejection fraction and cardiac wall motion were also analyzed. The cardiac volume included in the radiation fields was calculated and evaluated to check for a correlation between the amount of irradiated cardiac volume and aspects of myocardial perfusion defects. $\underline{Results}$: A myocardial perfusion defect was detected in 11 of 32 patients (34.4%). There were 7 (46.7%) perfusion defect cases in 15 patients who underwent the two-dimensional simulation technique and 4 (23.5%) patients with perfusion defects in the three-dimensional simulation group (p=0.0312). In 10 of 11 patients who had myocardial perfusion changes, the perfusion defects were observed in the cardiac apex. The left ventricular ejection fraction was within the normal range and cardiac wall motion was normal in all patients. The irradiated cardiac volume of patients in the three-dimensional simulation group was less than that of patients who received the two-dimensional simulation technique, but there was no statistical significance as compared to the incidence of perfusion defects. $\underline{Conclusion}$: Radiotherapy with a CT simulator (three-dimensional simulation technique) for early left-sided breast cancer may reduce the size of the irradiated cardiac volume and the incidence of myocardial perfusion defects. Further investigation and a longer follow-up duration are needed to analyze the relationship between myocardial perfusion defects and clinical ischemic heart disease.

• Korean Journal of Weed Science
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• v.30 no.1
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• pp.1-16
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• 2010

This study was conducted to develope identification method with major broad leaved weed seedlings. Characteristics of weed seedlings were investigated at two to four true leaf stage. Qualitative characteristics were more useful to identification of weed species than quantitative characteristics at the seedling stage. Many species were elliptic and broadly elliptic type in their cotyledon shape. Cotyledon shape of Cassia nomame and Calystegia sepium were broadly oblong. Four species were transverse broadly elliptic in their cotyledon shape. Rumex japonicus, Persicaria hydropiper, Euphorbia supina and Acalypha australis have three or more types in their cotyledon shape. Cotyledons of Vigna angularis var. nipponensis remained below ground after its germination. Many species were round in apex and were cuneate in base of cotyledon. Humulus japonicus and Polygonum aviculare were sessile in cotyledon base. The second true leaf shape of some species changed after first leaf stages. Glycine soja, V. angularis var. nipponensis and Kummerowia striata were broadly ovate, heart-shaped, orbicular or broadly obovate in their first true leaf, respectively, but the second true leaf shape of them were tripalmately compound. Aeschynomene indica and Cassia nomame were paripinnately compound leaf in their first and second true leaves. Margin of true leaves were entire in many species but six species including Xanthium occidentale were dentate in their true leaf margins. Margin of Euphorbia supina was entire in first true leaf and dentate in second true leaf. Margin of Chenopodium album and C. serotinum were entire in their first true leaf stage and erose in their second true leaf stage. The key for weed seedling identification of major weed species were made based on quantitative and qualitative morphological characteristics.

• Restorative Dentistry and Endodontics
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• v.36 no.3
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• pp.231-237
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• 2011

Objectives: The purpose of this study was to determine the optimal master apical file size with minimal transportation and optimal efficiency in removing infected dentin. We evaluated the transportation of the canal center and the change in untouched areas after sequential preparation with a #25 to #40 file using 3 different instruments: stainless steel K-type (SS K-file) hand file, ProFile and LightSpeed using microcomputed tomography (MCT). Materials and Methods: Thirty extracted human mandibular molars with separated orifices and apical foramens on mesial canals were used. Teeth were randomly divided into three groups: SS K-file, Profile, LightSpeed and the root canals were instrumented using corresponding instruments from #20 to #40. All teeth were scanned with MCT before and after instrumentation. Cross section images were used to evaluate canal transportation and untouched area at 1-, 2-, 3-, and 5- mm level from the apex. Data were statistically analyzed according to 'repeated nested design' and Mann-Whitney test (p = 0.05). Results: In SS K-file group, canal transportation was significantly increased over #30 instrument. In the ProFile group, canal transportation was significantly increased after preparation with the #40 instrument at the 1- and 2- mm levels. LightSpeed group showed better centering ability than ProFile group after preparation with the #40 instrument at the 1 and 2 mm levels. Conclusions: SS K-file, Profile, and LightSpeed showed differences in the degree of apical transportation depending on the size of the master apical file.

• Journal of Chest Surgery
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• v.35 no.1
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• pp.1-10
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• 2002

Background: Despite the relatively high mortality rates in the chronic heart failure model induced by coronary artery ligation are relatively high, this model has been a subject of continuos research because of its clinical correlation. Chronic heart failure model of large-sized animals is very useful to analyse mechanical or biological effects on circulatory system which is difficult in small-sized animals. The purpose of this study is to establish the heart failure model by coronary artery ligation in sheep. Material and Method: Among 9 Corridale sheep, the homonymous artery and the diagonal branch were ligated simultaneously in 2 sheep and remaining 7 sheep were assigned to successive ligation of both arteries at an interval of 1 hour. Both coronary arteries were ligated from the point 40% proximal to the apex of the heart. Hemodynamic and echocardiographic parameters were analyzed before the ligation of the coronary artery, after the ligation of the homonymous artery, and after additional ligation of the diagonal branch. The experimental animals were sacrificed after 2 or 3 months of growth and histopathologic studies were performed Result: Immediate postoperative death occurred in the 2 sheep that had received simultaneous ligation of the homonymous artery and diagonal branch. On the other hand, all the 7 sheep that were lifated in succession were survived up to 3 months. Arterial pressure was sifnificantly decreased immediately after ligation of the homonymous artery(p<0.05), and the cardiac output was decreased and pulmonary capillary wedge pressure was increased after further ligation of the diagonal branch(p<0.05). Central venous pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, left ventricular end-diastolic dimension and end-systolic dimension were markedly increased 3 months after ligation of coronary arteries. Anteroseptal akinesia or dyskinesia was developed after the ligation of coronary arteries. Histopathologic study revealed we]1-demarcated ischemic area of fibrosis. Conclusion: Using methods of successive ligation of the homonymous artery and diagonal branch, chronic heart failure model could be reliably established in sheep.