• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.258-265
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• 1992

A low loss optical waveguide of $P_{2}O_{5}-SiO_{2}$on Si substrate is produced by using the chemical vapour deposition method of $SiO_2$ thin films used in Si technology. Propagation loss of the waveguide layer was 1.65 dB/cm as produced and reduced down to 0.1 dB/cm after heat treatment at $1100^{\circ}C$. By using laser lithography and reactive ion etching method $P_{2}O_{5}-SiO_{2}$ waveguide was produced and subsequently annealed at $1100^{\circ}C$.As a result of this annealing the shape of the waveguide core was changed from rectangular to semi-circular form, and the propagation loss was reduced as down to 0.03 dB/cm at 0.6328$\mu$m and 0.04dB/cm at 1.53$\mu$m. We think that the mechanism of the reduction in propagation loss during the heat treatment is the following: 1) The hydrogen bonding in waveguide layer, which causes absorption loss, is dissociated and diffused out. 2) The roughness of the interface and the micro-structure of the waveguide layer is removed. 3) The irregularities in the cross-sectional shape of the waveguide which was induced during the lithographic process were disappeared by flowing of the waveguide core.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.657-663
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• 2005

Collagenases are generally defined as enzymes that are capable of degrading the polypeptide backbone of native collagen under conditions that do not denature the protein. An extracellular collagenase-producing bacterial strain was isolated from kimchi and identified to be Bacillus subtilis JS-17 through morphological, cultural, biochemical characteristics and 16S rDNA sequence analysis. Optimum culture condition of Bacillus subtilis JS-17 for the production of collagenase was $1.5\%$ fructose, $1\%$ yeast extract, $0.5\%\;K_2HPO_4,\;0.4\%\;KH_2PO_4,\;0.01\%\;MgSO_4\cdot7H_2O,\;0.01\%\; MnSO_4\cdot4H_2O,\;,0.1\%$ citrate and $0.1\%\;CaCl_2$. The production of collagenase was optimal at $30^{\circ}C$ for 72 hr. A collagenase was isolated from the culture filtrate of Bacillus subtilis JS-17. The enzyme was purified using Amberlite IRA-900 column chromatography, Sephacryl S-300 HR column chromatography and DEAE-Sephadex A-50 column chromatography The purified collagenase has an specific activity 192.1 units/mg. The molecular weight of the purified enzyme was estimated to be 28 kDa by SDS-PACE. The purified collagenase has $100\%$ activity up to $55^{\circ}C$.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.85-97
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• 1998

The purpose of this study was to observe the effects of sodium fluoride on the bony repair and regeneration processes after the rapid palatal expansion in the growing dogs. Eighteen dogs were divided into experimental and control groups. They were in the late mixed dentition. The rapid Palatal expansion was undertaken in all the animals($180^{\circ}$ turn/day) for ten days. The animals were sacrificed on 0, 15 and 45 days after the finish of expansion. One mg NaF/kg of body weight/day were given orally to the experimental group. Blood samples were drawn before and after expansion and the se겨m calcium, phosphate and alkaline phosphatase level were measured. The undecalcified bone section of midpalatal suture area was made, and observed under the light microscopy The results were as follows ; 1. The day after expansion, the infiltration of inflammatory cells were prominent and the new bone formation started at the edges of the two palatal plates bodering the midpalatal suture in both groups. Especially, the newly formed osteoid were very extensive and the osteoblasts lining the osteoid were very active in the experimental group. 2. At fifteen days after expansion, the active osteoblasts lining the osteold at the surface of trabecular bony spicules and active new bone formation were observed in the both groups. However, the cellular activity and new bone formation were more prominent In the experimental group. 3. At forty five days after expansion, the continuous osteoid and new bone formation and active osteoblasts were observed in the experimental group. But these phenomena were not observed in the control group. In the control group, the numerous osteoclasts were adjacent midpalatal suture and the bony remodeling process was begun. The serum alkaline phosphatase level was maintained highly in the experimental group, but decreased in the control. According to the above results, the author reached the conclusion that sodium fluoride has the stimulation effects on the osteoid production of the osteoblasts during the healing process after the rapid Palatal expansion more continuously.

• Journal of Oral Medicine and Pain
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• v.33 no.2
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• pp.195-204
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• 2008

Osteoarthritis is caused by joint degeneration, a process that includes progressive loss of articular cartilage accompanied by attempted repair of articular cartilage, remodeling and sclerosis of subchondral bone, and osteophyte formation. The most common causative factor that either causes or contributes to osteoarthritis is overloading of the articular structures of the joint. The diagnosis of temporomandibular joint(TMJ) osteoarthritis is based on the patient's history and clinical findings such as limited mandibular opening, crepitation and tenderness to palpation on TMJ. The diagnosis is usually confirmed by TMJ radiographs, which will reveal evidence of structural changes in the subarticular bone of the condyle or fossa. Plain radiography techniques such as panoramic, transcranial, transpharyngeal views can be used in most dental offices for evaluation of the TMJs. However, plain radiographs are often limited due to overlapping and distortion of anatomical structures. The aim of this study was to compare the clinical examination and panoramic view with computed tomography for diagnosis of temporomandibular degenerative joint disease, and to compare the findings of condylar bony changes through panoramic radiography with that of computed tomography, hence, to confirm the limitations of clinical and panoramic radiography, and the validity of the computed tomography for diagnosis of temporomandibular degenerative joint disease. The pathophysiology of the TMJ osteoarthritis remains poorly understood, and current treatments are based more on speculation than science, and symptomatic treatments often fail to provide satisfactory pain relief. For diagnosis of TMJ osteoarthritis, clinical examination and radiographic examination for confirmation of the bony changes are essential, and computed tomography are clearly superior to plain radiographs for their limitations.

• Journal of Chest Surgery
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• v.36 no.2
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• pp.73-78
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• 2003

The Fontan operation has undergone a number of major modifications and clinical results have been improving over time. Nevertheless, during the follow-up period, life-threatening complications develop and affect the long-term outcomes. Surgical interventions for these complications are needed and are increasing. Material and Method: From April 1988 to January 2000, 16 patients underwent reoperations for complications after Fontan operation. The mean age at reoperation was 8.8 :-5.5 years. Initial Fontan operations were atriopulmonary connections in 8 and total cavopulmonary connections in 8. Total cavopulmonary connections were accomplished with intracardiac lateral tunnel in 5 and extracardiac epicardial lateral tunnel in 3. Five patients had variable sized fenestrations. The reasons for reoperations included residual shunt in 6, pulmonary venous obstruction in 3, atrial flutter in 3, atrioventricular valve regurgitation in 2, Fontan pathway stenosis in 1, and protein-losing enteropathy in 1 Result: There were 3 early and late deaths respectively Patients who had residual shunts underwent primary closure of shunt site (n=2), atrial reseptation for separation between systemic and pulmonary vein (n=2), conversion to lateral tunnel (n=1), and conversion to one and a half ventricular repair (n=1). Four patients who had stenotic lesion of pulmonary vein or Fontan pathway underwent widening of the lesion (n=3) and left pneumonectomy (n=1) In cases of atrial flutter, conversion to lateral tunnel after revision of atriopulmonary connections was performed (n=3). For the atrioventricular valve regurgitation (n=2), we performed a replacement with mechanical valve. In one patient who had developed protein-losing enteropathy, aorto-pulmonary collateral arteries were obliterated via thoracotomy. Cryoablation was performed concomitantly in 4 patients as an additional treatment modality of atrial arrhythmia. Conclusion: Complications after Fontan operation are difficult to manage and have a considerable morbidity and mortality. However, more accurate understanding of Fontan physiology and technical advancement increased the possibility of treatment for such complications as well as Fontan operation itself. Appropriate surgical treatment for these patients relieved the symptoms and improved the functional class, Although the results were not satisfactory enough in all patients.

• Applied Microscopy
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• v.31 no.1
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• pp.71-83
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• 2001

Laminin, a kind of multidomain glycoproteins, is mainly localized in the basement membranes of various tissues. It is known that laminin plays an important part in mammalian lung morphogenesis. The authors have undertaken this study to investigate the changes in the distribution of laminin, and to find out cells which synthesize laminin during the organogenesis and differentiation of the lung. The fetal and neoantal rats (Sprague-Dawley strain) were used as experimental animals. The immunohisto-chemical methods were employed for detection of laminin within the developing lung tissue and the immunegold cytochemical methods were performed for detection of cells which synthesize laminin according to each stage of development. The results are as follows; 1. During fetal life, strong immunoreactivity for laminin is maintained in the basement membranes of the blood vessels and the bronchioles, the extracellular matrix of the mesenchyme, and basal lamina of the alveolar septum in the fetal rat lung. 2. After birth, laminin immunoreactivity at the alveolar septum is gradually reduced. 3. During fetal life, laminin is mainly detected within the cytoplasm of the mesenchymal cells, the endothelial cells of blood vessels and the fibroblasts in fetal rat lung. 4. According to the differentiation of type I and type II pneumocyte after birth, laminin is detected within cytoplasm of the type I pneumocytes, type II pneumocytes and fibroblasts. It is consequently suggested that laminin is largely expressed in the developing lung and laminin may be also synthesized by the type II pneumonocytes at early newborn stages.

• Applied Microscopy
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• v.31 no.1
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• pp.19-35
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• 2001

Outlines for plasma $estradiol-17\beta$, components, electrophoretic patterns, and ultrastructural changes were obtained in female rainbow trout (Oncorhynchus mykiss) during the seasonal reproductive cycles. Plasma $estradiol-17\beta$ under the natural conditions, exhibited distinct seasonal variation, peaking very late in vitellogenic season during September, decreasing gradually the halt of spawning in December, and ultimately falling during the early stages of seasonal ovarian recrudescence in February and March. This change in $estradiol-17\beta$ appeared to stimulate vitellogenin production as evidenced by increases in plasma calcium, phosphorus, glucose, albumin and total protein levels. The electrophoretic patterns of late maturing or spawning oocytes were stained more intensively than those of late perinucleolus oocytes (molecular weights of approximately 70,000 and 200,000). Two protein bands were found in the SDS-PAGE separation, coincident with the $estradiol-17\beta$ hormone peak. Gonadosomatic indices (GSI) significantly increased from October to January, and showed the highest peak in January, coinciding with the numerically abrupt increase of ripe ova in female. A positive correlation (r=0.701, p<0.01) was established between plasma $estradiol-17\beta$ levels and the gonadosomatic index during the prespawning. The highest level of hepatosomatic index (HSI) observed in December. During the breeding season (December), the gonadotropes were large and filled with GTH-containing inclusions such as granules and globules. The vitellogenic phase began as late perinurleolus oocytes became transformed into early maturing oocytes through the accumulation of yolk, and oocytes reached the late maturing stages as the ooplasm was completely packed with yolk. Marked ultrastructural changed in the granulosa cells during nuclear migration involve the dilation of the rough endoplasmic reticulum and the appearance of the rod-shaped mitochondria with tubular cristae. Microvilli (finger-like projections), from the zona radiata and from the oocyte grew, and made contact with each other in the pore canals of the zona radials during vitellogenesis, but were withdrawn as the zona radiata became more compact and devoid of pore canals during oocyte maturation. The zona radiata grew to a tripartite structure such as an outer thin homogeneous layer, and two inner thick helicoidal layers (zona radials interna and zona radiata externa). Under the normal conditions, the ovarian follicle influenced the histological development and periodical secretion of the hormones , sufficient for a oogenesis and gonadal steroid production.

• Journal of Periodontal and Implant Science
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• v.23 no.3
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• pp.535-563
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• 1993

New techniques for regenerating the destructed periodontal tissue have been studied for many years. Current acceptable methods of promoting periodontal regeneration alre basis of removal of diseased soft tissue, root treatment, guided tissue regeneration, graft materials, biological mediators. Platelet-derived growth factor (PDGF) is one of polypeptide growth factor. PDGF have been reported as a biological mediator which regulate activities of wound healing progress including cell proliferation, migration, and metabolism. The purposes of this study is to evaluate the possibility of using the PDGF as a regeneration promoting agent for furcation involvement defect. Eight adult mongrel dogs were used in this experiment. The dogs were anesthetized with Pentobarbital Sodium (25-30 mg/kg of body weight, Tokyo chemical Co., Japan) and conventional periodontal prophylaxis were performed with ultrasonic scaler. With intrasulcular and crestal incision, mucoperiosteal flap was elevated. Following decortication with 1/2 high speed round bur, degree III furcation defect was made on mandibular second(P2) and fourth(P4) premolar. For the basic treatment of root surface, fully saturated citric acid was applied on the exposed root surface for 3 minutes. On the right P4 20ug of human recombinant PDGF-BB dissolved in acetic acid was applied with polypropylene autopipette. On the left P2 and right P2 PDGF-BB was applied after insertion of ${\beta}-Tricalcium$ phosphate(TCP) and collagen (Collatape) respectively. Left mandibular P4 was used as control. Systemic antibiotics (Penicillin-G benzathine and penicillin-G procaine, 1 ml per 10-25 1bs body weight) were administrated intramuscular for 2 weeks after surgery. Irrigation with 0.1% Chlorhexidine Gluconate around operated sites was performed during the whole experimental period except one day immediate after surgery. Soft diets were fed through the whole experiment period. After 2, 4, 8, 12 weeks, the animals were sacrificed by perfusion technique. Tissue block was excised including the tooth and prepared for light microscope with H-E staining. At 2 weeks after surgery, therer were rapid osteogenesis phenomenon on the defected area of the PDGF only treated group and early trabeculation pattern was made with new osteoid tissue produced by activated osteoblast. Bone formation was almost completed to the fornix of furcation by 8 weeks after surgery. New cementum fromation was observed from 2 weeks after surgery, and the thickness was increased until 8 weeks with typical Sharpey’s fibers reembedded into new bone and cementum. In both PDGF-BB with TCP group and PDGF-BB with Collagen group, regeneration process including new bone and new cementum formation and the group especially in the early weeks. It might be thought that the migration of actively proliferating cells was prohibited by the graft materials. In conclusion, platelet-derived growth factor can promote rapid osteogenesis during early stage of periodontal tissue regeneration.