• Progress in Medical Physics
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• v.21 no.2
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• pp.137-144
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• 2010

The purpose of this study was to evaluate the usefulness of reducing of craniofacial radiation dose using automatic exposure control (AEC) technique in the 64 multi-detector computed tomography (MDCT). We used SOMATOM Definition 64 multi-detector CT, and head of whole body phantom (KUPBU-50, Kyoto Kagaku CO. Ltd). The protocol were helical scan method with 120 kVp, 1 sec of rotation time, 5 mm of slice thickness and increment, 250 mm of FOV, $512{\times}512$ of matrix size, $64{\times}0.625\;mm$ of collimation, and 1 of pitch. The evaluation of dose reducing effect was compared the fixed tube current of 350 with AEC technique. The image quality was measured the noise using standard deviation of CT number. The range of craniofacial bone was to mentum end from calvaria apex, which devided three regions: calvaria~superciliary ridge (1 segment), superciliary ridge~acanthion (2 segment), and acanthion~mentum (3 segment). In the fixed tube current technique, CTDIvol was 57.7 mGy, DLP was $640.2\;mGy{\cdot}cm$ in the all regions. The AEC technique was showed that 1 segment were 30.7 mGy of CTDIvol, 340.7 $mGy{\cdot}cm$ of DLP, 2 segment were 46.5 mGy of CTDIvol, $515.0\;mGy{\cdot}cm$ of DLP, and 3 segment were 30.3 mGy of CTDIvol, $337.0\;mGy{\cdot}cm$ of DLP. The standard deviation of CT number was 2.622 with the fixed tube current technique and 3.023 with the AEC technique in the 1 segment, was 3.118 with the fixed tube current technique and 3.379 with the AEC technique in the 2 segment, was 2.670 with the fixed tube current technique and 3.186 with the AEC technique in the 3 segment. The craniofacial radiation dose using AEC Technique in the 64 MDCT was evaluated the usefulness of reducing for the eye, the parotid and thyroid with high radiation sensitivity particularly.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1528-1533
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• 2002

Purpose : Isolated noncompaction of the ventricular myocardium(INVM) is one of the unclassified cardiomyopathies that is characterized by numerous, excessively prominent trabeculations, and deep intertrabecular recesses. We performed this study to evaluate the clinical features of INVM in children. Methods : The medical records of 10 patients with INVM were reviewed. We analyzed the clinical manifestations, hemodynamics, pattern of inheritance, and long-term prognosis of INVM in children. Results : Age at diagnosis was $45{\pm}53months$(1 day-14 years) with follow-up lasting as long as 78 months. Most INVM was asymptomatic on diagnosis. Associated cardiac anomalies were noted in six patients(ventricualr or atrial septal defect, patent ductus arteriosus with mitral valve prolapse, or mitral valve cleft). Depressed or flat changes of T wave in lead II, III and aVF were observed on electrocardiography. Various arrhythmia including WPW syndrome with paroxysmal supraventricular tachycardia, third-degree atrioventricular block, and familial sick sinus node dysfuction were observed. The degree of trabeculation in INVM was significantly prominent from level of mitral valve to apex compared to age-matched control. Familial recurrences were noted in two patients. The systolic function of the left ventricle was decreased in 20% of patients during the follow-up period, but systemic embolism or ventricular tachycardia was not observed. Conclusion : INVM is not a rare disorder. The cardiac function may be deteriorated in children as well as adults during long-term follow up. Thus early diagnosis and long-term follow-up must be done. So, the nation-wide multicenter clinical study would be mandatory to evaluate the incidence, long-term prognosis, and establishment of objective diagnostic criteria of INVM.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.341-346
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• 1987

Seven barley varieties were tested under three different vernalization durations for observing the effects of vernalization duration and different growth habit on shoot apex development and heading date. The final leaf number per main stem in 3 and 6 weeks vernalized seedlings did not vary among varieties, but ranged 7 to 14 leaves in non-vernalized seedlings. The winter types had more leaves than the spring types. Days for each leaf emergence in non-vernalization were retarded 1. 3 to 1. 5 days in comparison with 3 or 6 weeks vernalized seedlings. In general, the leaf emergence speed of spring types was faster than that of winter types. The VI stage whose double ridge formed, did not vary in 6 weeks vernalization, but spring (Gangbori & Dongbori 2) and facultative or winter types showed two conspicuous difference patterns. The differences of days to X stage were great among different vernalization duration and varieties; the stage of spring types was reached faster than that of winter types. The early varieties within the same growth habit were reached to X stage faster, and the time of flag leaf emergence showed the similar tendency to the differentiation of X stage. The time of the first rapid stem internode elongation became late as for incompletely vernalized seedlings. The time within the same vernalization duration became later in winter types than in spring types, and even within the same growth habit, the time of early varieties became faster than that of late varieties. The growth habit in especially non-vernalized seedlings had highly significant correlation coefficients with the times of leaf development speed, leaf number per main stem, the first rapid stem internode and young spike elongations, X stage, and flag leaf emergence. However, the relationship between growth habit and time of heading in the field was not close.

• Journal of Veterinary Clinics
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• v.27 no.3
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• pp.273-283
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• 2010

The objective of this study was to measure densities in various areas of the normal canine lung with computed tomography (CT) depending on influences of gravity and the degree of lung inflation and to determine optimal positions and positive end expiratory pressure of canine lung for CT scanning. In each eight normal Beagle and Shihtzu dogs, a respiratory breathhold maneuver without spontaenous breathing at different positive end expiratory pressure (PEEP) of 0 mmHg, 10 mmHg and 20 mmHg was applied with the position of right and left lateral recumbency, sternal recumbency, and dorsal recumbency and spiral-CT scans of the total lung were acquired. Slices were selected at three levels through the apex, middle and basal lung at the aortic arch, carina and just above the diaphragm and lung density was measured in the dorsal, ventral, and lateral portions of the peripheral lung field. Lung density in dependent areas was higher than in nondependent areas (p < 0.05) regardless of species, positions, anatomic locations at the PEEP of 0 mmHg and 10 mmHg. However, no significant difference of lung density was found at PEEP of 20 mmHg in both species except the dorsal recumbency in Shihtzu dogs. This density gradient in the dependent areas is strongly influenced by PEEP (p < 0.05). In the four positions on the CT gantry, the lung density at the dependent and nondependent location of the lung was greater at the aortic arch than at the base (p < 0.05). Lung density decreased on identical location according to increase of PEEP (p < 0.05). There was no significant difference between right and left lung density at sternal and dorsal recumbency and no significant difference of the dorsal, ventral, and lateral portions of lung density at the right and left recumbency under identical pressure. It is implied that during chest CT scan with 20 mmHg of positive end expiratory pressure with right or left lateral recumbency, canine lung density do not influenced by gravity or anatomic location.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.3
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• pp.169-176
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• 2006

Purpose: According to the development of CT scanner in PET/CT system, the role of CT unit as a diagnostic tool has been more important. To improve the diagnostic ability of CT scanner, it is a key aspect that CT scanning has to be performed with high dose energy and intravenous (IV) contrast. So we investigated the effect of IV contrast media on the maximum SUV (maxSUV) of normal tissues and pathologic lesions using PET/CT scanner with high dose CT scanning. Materials & Methods: The study enrolled 13 patients who required PET/CT evaluation. At first, the patients were performed whole body non-contrast CT (NCCT-120 kVp, 130 mAs) scan. Then contrast enhanced CT (CECT) scan was performed immediately. Finally PET scan was followed. The PET omission data were reconstructed twice, once with the NCCT and again with the CECT. We measured the maxSUV of 10 different body regions that were considered as normal in ail patients. Also pathologic lesions were investigated. Results: There were not seen focal artifacts in PET images based on CT with IV contrast agent. Firstly, 130 normal regions in 13 patients were evaluated. The maxSUV was significantly different between two PET images (p<0.00)). The maxSUV was $1.1{\pm}0.5$ in PET images with CECT-corrected attenuation and $1.0{\pm}0.5$ in PET images with NCCI-corrected attenuation. The limit of agreement was $0.1{\pm}0.3$ in Bland-Altman analysis. Especially there were significant differences in 6 of 10 regions, apex and base of the right lung, ascending aorta, segment 6 & segment 8 of the liver and spleen (p<0.05). Secondly, 39 pathologic lesions were evaluated. The maxSUV was significantly different between two PET images (p<0.001). The maxSUV was $4.7{\pm}2.0$ in PET images with CECT-corrected attenuation and $4.4{\pm}2.0$ in PET images with NCCT-corrected attenuation. The limit of agreement was $0.4{\pm}0.8$ in Bland-Altman analysis. Conclusion: Although there were increases of maxSUVs in the PET images based on CT with IV contrast agent, it was very narrow in the range of limit of agreement. So there was no significant effect to clinical interpretation for PET images that were corrected attenuation with high dose CT using IV contrast.

• Applied Microscopy
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• v.38 no.2
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• pp.117-124
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• 2008

Salvinia is an aquatic plant forming dimorphic leaves that have been modified into floating and submerged leaves. A air of floating leaves plays an important role for the floating and photosynthesis while the submerged leaves, which are lim and long, have the form and function of root. Many aquatic plants develop trichomes in the epidermis but in Salvinia, richomes grow densely in the epidermis of the dimorphic leaves. The present study examined the differentiation pattern of trichomes developing in the floating leaves of S. natans and S. molesta by scanning and transmission electron microscopy. Trichomes developing in the floating leaves of Salvinia showed very different patterns. In S. natans, they were arranged in a V-shape form, having 20${\sim}$25 rows at $18{\sim}25^{\circ}$ on both sides of the lamina divided by the midrib in the floating leaf. In each row, 8${\sim}$10 oval-shaped cells, $200{\sim}290{\mu}m$ in length, were arranged in a spiral fashion. Four trichomes of this form made a trichome unit, but their apical parts were separated from one another and developed into the so-called 'knuckle-crane' type. On the other hand, in S. molesta, trichomes differentiated in a unique pattern quite different from those of S. natans. At the early stage of differentiation, trichomes protruded from the epidermis and then 4${\sim}$6 cylindrical cells grew $400{\sim}600{\mu}m$ long and the four trichomes formed as an unit. The four grouped trichomes were interconnected through their apex and developed in the 'egg-beater' type. Then $300{\sim}600{\mu}m$ long multi-cellular stalk cells grew and protruded out of the epidermal surface from the basal part of the trichomes. Such a structural characteristic of trichomes is considered to play a very important role along with the aerenchyma tissue in the leaf mesophyll tissue for the floating of Salvinia on the water surface.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.90-96
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• 2012

Supernumerary tooth occurs most frequently at premaxilla area. Followed by mandibular premolar area, mandibular fourth molar area, maxillary paramolar area. Mesiodens are mainly impacted in the palatal area and surgical approach is made at palatal side. The time of surgery remains controversial. In case of inverted or horizontal impacted supernumerary tooth, intraosseous tooth movement and vertical growth of premaxilla makes surgical extraction more difficult. And also the more quantity of removed bone is, the higher degree of difficulty is. Inverted mesiodens of these cases were impacted superior to apex level of adjacent permanent incisor. Although CT examination revealed exact location of impacted tooth, surgical procedure including ostectomy may take a long time more than expected. So, before surgical extraction, it's need to be considered several factors such as necessity of CT taking, degree of difficulty, direction of surgical approach, necessity of general anesthesia etc.

• Tuberculosis and Respiratory Diseases
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• v.50 no.4
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• pp.415-425
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• 2001

Background : The correlation between the high resolution computed tomography(HRCT) emphysema score and the physiologic parameters including resting and exercise pulmonary function test was investigated in 14 patients($60.6{\pm}10.3$ years) with pulmonary emphysema. Methods : The patients underwent a HRCT, a resting pulmonary function test, and incremental exercise testing(cycle ergometer, 10 W/min). Computed tomography scans were obtained on a GE highlight at 10 mm intervals using 10 mm collimation, from the apex to the base after a full inspiration. The emphysema scores were determined by a CT program 'Density mask' outlining the areas with attenuation values less than -900 HU, indicating the emphysema areas, and providing an overall percentage of lung involvement by emphysema. Results : Among the resting PFT parameters, only the diffusing capacity(r=-0.75) and $PaO_2$ (r=-0.66) correlated with the emphysema score(p<0.05). Among the exercise test parameters, the emphysema score correlated significantly with the maximum power(r=-0.74), maximum oxygen consumption(r=-0.68), anaerobic threshold(V-slope method: r=-0.69), maximal $O_2$-pulse(r=-0.73), and the physiologic dead space ratio at the maximum workload(r=-0.80)(p<0.01). Conclusion: We could find that exercise testing parameters showed a much better correlation with the HRCT emphysema score, which is known to have a good correlation with the pathologic severity than the resting PIT parameters. Therefore it is suggested that exercise testing is superior to resting PIT for estimating in the estimation of the physiologic disturbance in emphysema patients.

• Korean Journal of Environment and Ecology
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• v.22 no.1
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• pp.18-34
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• 2008

Based on external morphology, each of five species can be classified into three groups: 1) B. falcatum group (B. falcatum, B. scorzonerifolium), 2) B. euphorbioides group (B. euphorbioides) and 3) B. longiradiatum group (B. longiradiatum, B. latissimum). B. falcatum group has cauline leaves linear or lanceolate in shape and attenuate at base and not surrounding the stem. In contrast, B. longiradiatum group and B. euphorbioides group have cauline leaves ovate, lanceolate or panduriform in shape and auriculate or cordate at base and completely surrounding the stem. The inflorescence is basically compound umbels terminated at the apex of stem. But B. euphorbioides group is small in size and pedicels are rather short and the number of the pedicel is ca. 20. On the other hand, B. longiradiatum and B. falcatum groups are large in size and their pedicels are long and the number of the pedicel is around 10. The pore of pollen aperture of B. longiradiatum and B. latissimum is partially projected or not while those of B. falcatum group and B. euphorbioides is usually remarkably projected. The number of somatic chromosomes was counted as 2n=20 in B. falcatum, 2n=12 in B. scorzonerifolium and B. longiradiatum, and 2n=16 in B. euphorbioides and B. latissimum. Although chromosome numbers of B. euphorbioides and B. latissimum are the same, the two species are not likely to relate because the karyotypes of the two species are different from each other. Based on these observations, it can be concluded that B. latissimum is most closely related to B. longiradiatum. However, molecular data indicated that the species is probably related to B. bicaule distributed in central Siberia. In terms of conservation of B. latissimum, overexploitation by human and grazing by goat are most threatened factors.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.423-435
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• 1984

The reproductive cycle of the small filefish, Rudarius ercodes was investigated based on the annual variations of gonadosomatic index(GSI) and hepatosomatic index(HSI) by electronic and photic microscophy. The specimens used were collected at the coastal area of Benden island, Sizuokagen, Japan, from September 1982 to August 1983. GSI began to increase from March, starting season of longer daylength and higher water temperature, and reached the maximum value between June and August. It began to decrease from September with the lowest value appearing between November and February without any evident variation. The annual variations of HSI were not distinct in male filefish and were negatively related to GSI in female : HSI decreased in the summer season when the ovary was getting mature and reached the maximum in the winter season when the ovary was getting retrogressive. The ovary consisted of a pair of saccular structure with numerous ovarian sacs branched toward the median cavity. Oogonia divided and proliferated along the germinal epithelium of the ovarian sac. Young oocytes with basophile cytoplasm showed several scattering nucleoli along the nuclear membrane. when the oocytes growing to about 300 ${\mu}m$, nuclear membrane to disappear with nucleus migrating toward the animal pole. The regions of protoplasm were extremely confined within the animal hemisphere in which most of cytoplasms were filled with yolk materials and oil drops. After ovulation, residual follicles and growing oocytes remaining in the ovarian sacs degenerated. But perinucleatic young oocytes without follicles formed were not degenerated, and growing continuously still in the next year. Mitochondria and endoplasmic reticula in the cytoplasm remarkably increased with oocytes maturing and yolk accumulating. Those were considered to be functionally related to the yolk accumulation. Five or six layers of possible vitellogenin, oval-shaped disc structures with high electron density, appeared in the apex of follicular processes stretching to the microvilli pits of mature oocytes. Testis consisting of a pair of lobular structures in the right and left were united in the posterior seminal vesicle, Cortex of testis was composed of several seminiferous tubules, and medulla consisting of many sperm ducts connected with tubules. Steroid hormone-secreting cells with numerous endoplasmic reticula and large mitochondria of well developed cristae were recognized in the interstitial cells of the growing testis. Axial filament of spermatozoon invaginated deeply in the central cavity of the nucleus and the head formed U-shape with acrosome severely lacking, mitochondria formed large globular paranuclei at the posterior head, and microtubular axoneme of the tail represented 9+9+2 type. The annual reproductive cycles could be divided into five successive stages : growth(March to July), maturation(May to September), Spawning(mid May to early October) and resting stages(October to February). The spawning peak occurred from June to August.