• Journal of Korean Neurosurgical Society
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• v.29 no.3
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• pp.379-388
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• 2000

Objective : Although transoral transpharyngeal approach is a very useful method for the lesions of craniovertebral junction, it is not frequently used because of anatomical unfamilarity, risk of cerebrospinal fluid(CSF) leakage, and resultant postoperative meningitis. To evaluate the usefulness of transoral transpharyngeal approach for various lesions of craniovertebral junction, clinical characteristics and the results of this approach are investigated. Methods : Transoral transpharyngeal approaches were performed in eight cases between 1996 and 1999. Among them, there were three basilar invaginations due to congenital anomalies, two odontoid type I fractures, two atlantoaxial dislocations, and one pseudotumor. Surgical methods included five cases of anterior decompression and posterior fusion, two anterior approaches for decompression and one transoral approach for biopsy. Results : This procedure allowed immediate clinical improvement in all cases. In seven patients with preoperative motor deficit showed a progressive neurological improvement. The follow-up plain x-rays demonstrated successful bony fusion in all patients. Only one patient suffered from postoperative wound dehiscence, but she completely recovered after wound revision. There was no complication of postoperative CSF leakages. Conclusions : Transoral transpharyngeal approach for the ventral lesions of craniovertebral junction, can be used as a relatively simple and effective method.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.632-637
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• 2014

A microfluidic method for the in situ production of monodispersed alginate hydrogels using biocompatible polymer gelation by crosslinker mass transfer is described. Gelation of the hydrogel was achieved in situ by the dispersed calcium ion in the microfluidic device. The capillary number (Ca) and the flow rate of the disperse phase which are important operating parameters mainly influenced the formation of three distinctive flow regions, such as dripping, jetting, and unstable dripping. Under the formation of dripping region, monodispersed alginate hydrogels having a narrow size distribution (C.V=2.71%) were produced in the microfluidic device and the size of the hydrogels, ranging from 30 to $60{\mu}m$, could be easily controlled by varying the flow rate, viscosity, and interfacial tension. This simple microfluidic method for the production of monodisperse alginate hydrogels shows strong potential for use in delivery systems of foods, cosmetics, inks, and drugs, and spherical alginate hydrogels which have biocompatibility will be applied to cell transplantation.

• Korean Journal of Plant Resources
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• v.26 no.2
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• pp.271-283
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• 2013

Morphology of Korean Scrophularia species were reviewed to clarify taxonomic characters, their variations and taxon delimitation. Habitats, root forms, foliaceous types, glandular trichomes on stems and leaves, flowering seasons, calyx shapes, corolla colors and shapes, as well as ovary basal shapes are diagnostic characters to classify series in this genus. From the result, 1) S. alata is distinguished from its closely related species S. takesimensis by lengths of stem ribs, widths of petioles, and types of corolla lobes; 2) S. buergeriana is characterized by spike-like inflorescences, short peduncles and pedicels, and yellowish green corollas; 3) lanceolate-shaped leaves and calyces, and axillary-like cyme inflorescences delimitate S. koraiensis easily from the other taxa; 4) smaller leaves discriminate S. kakudensis var. microphylla from S. kakudensis var. kakudensis, and 5) S. cephalantha is distinguished from S. kakudensis by broadly ovate to sub-orbicular shaped leaves, earlier flowering seasons, and smaller numbered flowers on shorter inflorescences. In conclusion, the Korean Scrophularia is classified as 7 taxa, 6 species and 1 variety in 2 series. Keys to the series and taxa are provided.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.341-346
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• 2015

In this study, poly ${\varepsilon}$-caprolactone(PCL) microcapsules containing lemongrass oil was prepared by the solvent evaporation method. Effects of concentrations of PCL and poly vinyl alcohol (PVA) as well as stirring speeds when preparing microcapsules were investigated. Specific peaks of lemongrass oil in PCL microcapsules at 1600 and $2900cm^{-1}$ were observed by FT-IR. The particle size and shape of microcapsules were also measured by polarizing microscope and optical microscopy. The average particle size of microcapsules decreased with increasing the stirring rate. At the stirring speed of 1500 rpm, and 1 wt% of each PCL and PVA concentrations, the smallest particles were formed. Collection efficiencies of lemongrass oil of 77.5% and 69.5% were obtained when 1.5 wt% of PCL and 2 wt% of PVA were used, respectively. In addition, the release behavior and antioxidant activity of lemongrass oil from PCL microcapsules were examined using UV-Vis spectrophotometry. When 0.5 wt% PCL and 2.0 wt% PVA were used with the slow stirring rate, microcapsules showed a fast release rate. The characteristics of antioxidant activity exhibited similar to that of the release behavior.

• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.199-207
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• 2001

The segmented TMA T-loop spring, used for reciprocal space closure and described by Burstone, was used to achievebodily movement of canine. Photoelastic analysis is a technique for the transformation of internal stress into visible light patterns. The two-dimensional photoelastic stress analysis was performed, and stress distribution was recorded by photography. The purpose of this study was to visualize photoelastically the distribution of forces transmitted to the alveolus and surrounding structures using new segmented TMA T-loop spring for canine retraction. The results were as follows: 1. Decreased activation produced decreased stress of upper 1st. premolar extraction site and increased intrusive stress of upper 1st. molar, regardless of T-loop position. 2. At 5mm activation, More posterior positioning of T-loop Produced an increased stress in upper 1st. premolar extraction site. 3. At 3mm activation, More posterior positioning of T-loop produced an increased stress in upper 1st. premolar extraction site and mesial lower half of upper 1st. molar mesio-buccal root. 4. At 1mm activation, More anterior positioning of T-loop produced an increased stress in upper mesial and blew apex area of upper canine root. 5. 0.25 B/L ratio and 3mm activation produced bodily movement of canine. To summarize, desired tooth movement and anchorage requirement is possible by altering the activation and mesio-distal position of the T-loop spring.

• Development and Reproduction
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• v.7 no.1
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• pp.29-34
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• 2003

Anatomical and histological observations were used to examine the morphological differentiation and development of the digestive tract during ontogenesis in tiger puffer, Taklyugu rubripes. Before hatching, the digestive tract was located between yolk sac and notochord of embryo. Newly hatched larvae had a straight tubular digestive tract. The larval mouth opened at 2 days after hatching (DAH). At 4 DAH, sphincters separated the digestive tract into the esophagus, anterior intestine, mid-intestine and rectum, and the anus was opened. At 5 DAH, the larval intestine bent between the anterior and intermediate parts and mucous cells developed in the esophageal epithelium. At this time yolk sac was absorbed completely. At 6 DAM, the digestive tract was differentiated into the U type with expansion of the anterior intestine toward the head of the larvae. At 10 DAH, the expanding anterior intestine became wider and a elliptical. At 15 DAH, the anterior intestine was divided into two portions by invagination of dorsal epithelium and the mid-intestine was convoluted dorsally. At 21 DAM, the frontal portion of the anterior intestine formed a differentiated expansion sac. At 24 DAH, the second convolution was observed in the anterior part of the posterior intestine. At 30 DAH the expansion sac was extended longitudinally and the digestive tract took on the form seen in adult fish.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.260-266
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• 2010

Trauma to the primary teeth may have an effect on the successive permanent teeth. Thus, the treatment plans should be focused on safety of their permanent teeth. The degree of developmental disturbances in those permanent teeth depends upon many factors including the age of the children, developmental conditions of the affected teeth, types and severities of trauma and time interval from the moment of trauma to the initial treatment the patients received. The complications of the effected permanent teeth vary from the mild enamel hypoplasia to the premature finishing of teeth development. In this study, children whose ages were 33 months, 5 years, and 26 months presented the developmental disturbances to their permanent teeth, which resulted from the trauma to the primary teeth: the intrusion, the avulsion, and the subluxation. There showed a mild complication in the case of subluxation resulting in enamel hypoplasia, but, the more severe complication of the root dilacerations occurred in the case of intrusion. Furthermore, the 5-year-old patient whose primary dentition was near in transition period to the permanent one, the more complicated problem such as stop of root development of the permanent teeth was resulted from the avulsion. Thus, one should assume that the types of trauma and the age of the children at the moment of trauma have different effects on those successive permanent teeth. In conclusion, when the trauma that causes changes in the position of primary teeth happened, it is important to arrange an appropriate treatment procedure considering the types of trauma and the developmental conditions of the permanent teeth.

• Applied Microscopy
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• v.30 no.3
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• pp.273-283
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• 2000

To investigate the defensive effect of green tea against the lead toxicity, Sprague-Dewley rats (150 gm) were divided into 5 groups; the control group (A), the group treated with lead for 4 weeks (Group B-1), the group treated with lead and green tea for 4 weeks (Group B-2), the group treated with lead for 8 weeks (Group C-1), and the group treated with lead and green tea for 8 weeks (Group C-2). The lead acetate (500 ppm) was injected two times for one week into the abdomen and green tea solution (3 g/100 ml distilled water) offered freely. The results of histological and biocheical study are as follows; 1. Blood Urea Nitrogen (BUN) were increased in all the tested groups. The Group B-1 was more increased than the Group B-2, and the Group C-1 more than the Group C-2. The values of Alkaline phosphatase (ALP) were also decreased in all the tested groups, as such the former phenomenon. 2 In the Group B-1, some microvilli, mitochondria and rER were modificated on epithelial cell of proximal renal tubules. The cristae of mitochondria were enlarged, microvilli and nucleus were observed normally on the Group B-2. The number of Microvilli, mitochodria and rER were decreased, many lysosomes and irregular nucleus observed in the Group C-1. In the Group C-2, microvilli were modificated slightly and other organelles were observed similary with the Group B-2.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.740-745
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• 2015

This study investigated the effect of different collection methods on physical properties of pectin hydrogels in microfluidic synthetic approach. The pectin hydrogels were simply produced by the incorporation of calcium ions dissolved in continuous mineral oil. Then, different collection methods, pipetting, tubing, and settling, for harvesting pectin hydrogels were applied. The settling method showed most uniform and monodispersed hydrogels. In the case of settling, a coefficient of variation was 3.46 which was lower than pipetting method (18.60) and tubing method (14.76). Under the settling method, we could control the size of hydrogels, ranging from $30{\mu}m$ to $180{\mu}m$, by simple manipulation of the viscosity of pectin and volumetric flow rate of dispersed and continuous phase. Finally, according to the characteristics of simple encapsulation of biological materials, we envision that the pectin hydrogels can be applied to drug delivery, food, and biocompatible materials.

• The Korean Journal of Zoology
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• v.32 no.3
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• pp.211-220
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• 1989

The fine structure of the aggregate glands-one of the capture thread producing organs-in the orb web spider, Nephila clavata L.Koch, is studied with light and electron microscopes. Gluey capture threads or sticky spirals of the orb web are originated from the silks of two flagelliform glands and four aggregate glands which are connected to the posterior spinnerets, and the arrangement fo their spigots(large spinning tubes) shows a charaterstic form called "triad". The aggregate galnd is composed of large and multilobed secretory portion and thick excretory duct surrounded by large irregular nodules. The excretory duct of the aggregate galnds basically consists of three superposed types of cells which are inner columnar epithelium, nodule-forming cells and outer connestives. The cuticles of the proximal duct near the secretory portion are composed of endocuticle and exocuticle, whereas ghe distal duct near the spinning tubes has a electron lucent subcuticle which had the functions of water removal and orientation of silk fibers. In the cytoplasmic process of the large and irregular nodule-forming cells surrounded by invaginations of the plasma membranes, numerous mitochondria and glycogen particles are contained. The maturational level of the nodule cells is perceived from the appearence of these cell inclusions. The secretory portion of the glands which porduce the secretory silk material shows two layers of the cells which are simple cuboidal epithelium and several connective layers. In the cytoplasm of the glandular epithelial cell, rough endoplasmic reticulums are well developed, and two types of secretory granules are observed. Between the adjacent epithelial cells, specialized septate junctions are formed along the plasma membranes.membranes.