• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.41-45
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• 2003

The researchers have studied on the effect of three main morphological types(nuclear, cortical, and subcapsular cataract) of age related cataract on refractive error. We also identified that spherical and cylinderical shift in each type of morphological cataract accoding to their locations and effect of intraocular pressure before and after cataract surgery. Nuclear cataract showed myopic shift while cortical cataract showed hyperopic shift, and subcapsular cataract showed not significant changes on both direction. Age related cataract subjects(120 eyes) only were recruited from sun-cheon area. We use optic section of slit lamp biomicroscope to identify the anatomical location of cataract, and optimal refractive correction determined by objective(retinoscope) and subjective refraction then spherical changes were calculated from the spherical eqivalent value. Intra-ocular pressure were measured by auto-tonometer before and 7 days after cataract has been replaced by IOL. The change in cylindrical power, usually A-P diameter decreased according to increases of age, A-P diameter increased because intra-ocular pressure rises by progression of cataract and this convertion with the rule astigmatism to against the rule astigmatism and this increases more by intra-ocular pressure.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.116-126
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• 2009

The use of short implants has been accepted risky from biomechanical point of view. However, short implants appear to be a long term viable solution according to recent clinical reports. The purpose of this study was to investigate the effect of different diameter and length of implant size to the different type of bone on the load distribution pattern. Stress analysis was performed using 3-dimensional finite element analysis(3D-FEA). A three-dimensional linear elastic model was generated. All implants modeled were of the various diameter(${\phi}4.0$, 4.5, 5.0 and 6.0 mm) and varied in length, at 7.0, 8.5 and 10.0 mm. Each implant was modeled with a titanium abutment screw and abutment. The implants were seated in a supporting D2 and D4 bone structure consisting of cortical and cancellous bone. An amount of 100 N occlusal load of vertical and $30^{\circ}$ angle to axis of implant and to buccolingual plane were applied. As a result, the maximum equivalent stress of D2 and D4 bones has been concentrated upper region of cortical bone. As the width of implant is increased, the equivalent stress is decreased in cancellous bone and stress was more homogeneously distributed along the implants in all types of bone. The short implant of diameter 5.0mm, 6.0mm showed effective stress distribution in D2 and D4 bone. The oblique force of 100N generated more concentrated stress on the D2 cortical bone. Within the limitations of this study, the use of short implant may offer a predictable treatment method in the vertically restricted sites.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.681-690
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• 2007

Mini implants had been used provisionally for the healing period of implants in the beginning. But it becomes used for the on-going purpose, because it is simple to use, economic and especially suitable for the overdenture. But there is few studies about the stability of mini implants, that is most important factor for the on-going purpose, and particularly the implant parameters affecting the initial stability. The purpose of this study was to evaluate the stress and the strain distribution pattern of immediate-loaded screw type orthodontic mini-implant and the parameters affecting the initial stability of immediate-loaded mini-implant. Two dimensional finite element models were made and contact non-linear finite element analysis was performed. The magnitude and distribution of Von Mises stresses were evaluated. The obtained results were as follows: 1. The stress was concentrated on the thread tip of an implant in the cortical bone. 2. The direction of load is the most important factor for the stress distribution in cortical bone. 3. The diameter of an implant is the most important factor for the stress distribution in the trabecular bone. In conclusion, if the horizontal load vector is successfully controlled, mini-implants, which diameter is under 3mm, can be used for the on-going purpose.

• Korean Journal of Veterinary Service
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• v.19 no.3
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• pp.227-237
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• 1996

In order to investigate the prevalence and pattern of renal lesions in sows, 250 kidneys collected from abattoir were examined grossly and histopathologically. The prevalence of renal lesions in sows was 46.8% (l17/250). Main gross findings were consisted of congestion and/or petechiation (21.6%), cortical enlargement (15.2%), renal cysts (6.0%), abscessation (4.4%), and infarction (1.5%). Principle microscopic lesions were composed of interstitial nephritis (25.6% ), glomerulosclerosis (13.6%), glomerular thrombosis (3.6%), amyloidosis (2.0%) and glomerulosclerosis (2.0%) Sixty four kidneys with interstitial nephritis was classified by 46 chronic and 18 acute cases. Among 34 kidneys with glomerulonephritis, there were divided into 18 membranous type, 9 proliferative type and 7 membranoproliferative type. For these results, it was confirmed that sows raised in Kwangju and Chonnam areas had been affected by a variety of pathological renal lesions.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.4
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• pp.269-274
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• 1993

This is the case report of huge complex odontoma treated with sagittal splitting of buccal bone plate and iliac bone graft in left mandible angle. The 22 years old patient was admitted to the department of Oral and Maxillofacial Surgery of Kyungpook National University Hospital with the chief complaint of swelling on the left mandible angle area. We used extra oral Risdon incision and splitted the buccal cortical bone after making the horizontal bone cut buccally. The tumor mass was removed with cutting into the pieces with surgical bur to prevent mandibular fracture. The dead space was grafted with autogenous iliac bone graft and the splitted buccal cortical bone was fixed with two L-type miniplate. After 12months follow up check, we noticed good process of bone healing and satisfactory aesthetic result. In this case, my operative approach provided the excellent surgical access to the hard tissue mass and minimized post operative complication comparing with the conventional surgical approaches.

• Animal Systematics, Evolution and Diversity
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• v.27 no.2
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• pp.115-122
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• 2011

The morphology of the two marine hypotrichous ciliates Apokeronopsis bergeri and A. ovalis, isolated from the Yellow Sea, Korea, are described based on live and protargol-impregnated specimens. It is the first time that these species have been recorded in Korea. In addition, the small subunit ribosomal RNA gene was sequenced for comparison with the public database. The genus Apokeronopsis has recently been established in the family Pseudokeronopsidae, and the two congeners of the Korean population share the following characteristics: one row of one or more buccal cirri; usually two frontoterminal cirri; midventral complex composed of two distinctly separated rows; one left and one right marginal row; number of transverse cirri, more than eight; absence of caudal cirri; two types of cortical granules. Apokeronopsis bergeri differs from A. ovalis primarily in body shape (fusiform vs. oval form), size (usually $260{\times}80{\mu}m$ vs. $160{\times}55{\mu}m$), type II cortical granules (oval vs. round shape; yellow-green vs. mostly colourless and only a few yellow-green in colour), and morphometric data (75-106 vs. 53-70 in adoral membranelles; 37-47 vs. 24-36 in frontal cirri; 9-15 vs. 1-2 in buccal cirri), as well as molecular data (2.87% of pairwise distance).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.6
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• pp.393-402
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• 2020

Objectives: Here, we present cases of mandibular fracture that were managed with the cortical lag screw fixation technique (CLSFT) in order to critically evaluate technique indications and limitations of application at various fracture sites. Materials and Methods: This was a retrospective cohort study. The study sample was composed of patients suffering from mandibular fractures that were treated by the CLSFT. The outcome variables were fracture type, duration of surgery, number of screws, and pattern of application. Other study categories included patient demographics and causes of injury. Chi-square tests were used to assess descriptive and inferential statistical differences, and the P-value was set at 0.05. Results: Thirty-three patients were included in the study sample, with a mean age of 30.9±11.5 years and a male predominance of 81.8%. The technique was applied more frequently in the anterior mandibular region (51.5%) than in other sites. Double CLSFT screws were required at the symphysis and parasymphysis, while single screws were used for body and angle regions. No intraoperative and postoperative variables were significantly different except for surgical duration, which was significantly different between the sites studied (P=0.035). Conclusion: We found that CLSFT is a rapid, cost-effective technique for the fixation of mandibular fractures yielding good treatment results and very limited complications. However, this technique is sensitive and requires surgical expertise to be applied to mandibular fractures that have specialized characteristics.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.2
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• pp.140-144
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• 2003

Ameloblastoma is cytologically a benign tumor, but is clinically characterized by infiltrative growth and high recurrency. The criteria for surgical treatment of ameloblastoma has not yet established and it is generally accepted that ameloblastoma be treated differently based on clinical types. The purpose of this paper is to consider effectiveness of enucleation in large-sized intraosseous ameloblastoma that has treated more frequently by radical treatment. 39 cases of the intraosseous ameloblastomas were treated by enucleation in the department of oral and maxillofacial surgery of Yonsei University, dental college from February 1990 to January 2001. 25 cases were selected because they were large in size that could produce facial disfigurement or pathologic fracture of jaws. They were radiographically characterized by the cortical bone that was expanded or eroded locally and histopathologically by 19 solid ameloblastomas and 6 intramural type of unicystic ameloblastomas. Among the 25 cases, 4 cases - 3 solid ameloblastomas and 1 intramural type of ameloblastoma - recurred. Recurrence rate was 16%. The compact bone which is not invaded by ameloblastoma was used as surgical margin of enucleation with accompanying chemical cauterization for killing the residual tumor cells. This may have been the reason for the low recurrence rate. So, it is considered that enucleation and long-term follow-up enable the large-sized intraosseous ameloblastomas that were characterized by almost destroyed cancellous bone and expanded or discontinued cortical bone to treat minimizing facial disfigurement and masticatory dysfunction and sociopsychological impact produced by radical treatment. I recommend that the large-sized intraosseous ameloblastomas without involvement to the surrounding soft tissues be first treated by enucleation.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.263-290
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• 1997

Homogenization technique is employed to investigate the series of stress analyses of mandible for three different types of dental implants. This technique helps to make proper material model of bone and analyze such a non homogeneous structure at the level of individual microstructural unit. The stress analyses with homogenization technique show much higher stress level in the sponge bone, compared to those of conventional FEM. It also manifested that even a minor lateral force results in crucial stresses in the dental implant system and that the macroscale model should take the shape and size after real mandible to produce reasonable solution in the analyses of dental implant systems. The shapes of dental implants simulated in this study are rectangular-cross-sectioned type, hemi-sphere rooted type, and wedge type implant. The stress states of mandible with hemisphere rooted type implant and wedge type implant show similar levels, while those with sectioned rectangular implant results in higher stresses. It is suggested that the distance between the implant tip and cortical bone be kept far enough to prevent stress concentrations in the mandible.

• ALGAE
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• v.19 no.3
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• pp.191-199
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• 2004

Morphological and phonological characteristics of brown alga Spatoglossum crassum Tanaka new to Korea were described based on the field and the indoor cultured plants. The taxonomic characteristics of the plants were agreed to those from the type locality-submerged reproductive organs in cortex, anatomical features, and absence of phaeophycean hairs on the surface. But they have rudimentary midrib on lower portion of thallus. We can observe the young plants on November, adult ones in June, and senile ones in August. This species has an annual life-cycle in the field, starting with germ lings in early November. The differentiation of thallus is quite different from other species of genera in tribe Zonarieae, e.g. Zonaria and Homoeostrichus. Three different tissues, meristoderm, cortex and medulla are discerned. The outmost cortical one celled layer as a meristoderm produce cortex by unequal periclinal division. In the apical cell division, the primary inner cells are developed into 3-4 cell layered medulla of thallus. The distribution of this species extends from Korea to Shizuoka Peninsula (34°40'N) Japan, which is the type locality of this species.