• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.105-114
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• 2015

Even though the passengers' safety has priority on Passenger ship, there is no criterion on the evacuation performance related with human behavior. To uncover the potential problems of domestic criteria on safety of passenger ships, this study performed simulation ad analysis the evacuees safety before and after the Sewol's remodelling. It is clear that the assembly stations of both before and after Sewol remodelling have sufficient areas to satisfy the domestic criterion by simply human- body's-area, but those are failed to assemble all the passengers by the simulation tool that reflects the human behaviors' characteristics. For the healing angle as 0 degree, and the criteria of SOLAS, it was found out that all the passengers can safely evacuate from each cabins to the embarkation stations for both of the before-and-after the Sewol remodelling. But for the healing angle as 20 degree, both of the before-and-after Sewol remodelling are evaluated as possible to make all the passengers evacuate for day scenario and impossible for night scenario of SOLAS criteria. And because of the worse conditions after the remodelling, the probabilities of Sewol(before) are showed wide band comparing to Naminoue (after).

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.13-23
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• 2002

The ultimate goal of periodontal therapy is directed to arresting the progression of the disease, and regenerating the fibrous attachment. In order to achieve such treatment aim, the plaque and calculus must be eliminated and the physiological conditions of the root surface must be changed to facilitate the attachment and migration of the new fibroblasts, The method of changing the proper root surface conditions to promote the healing of periodontal tissue involves mechanical procedures, such as scaling and root planing, and chemical procedures such as tetracycline-HCl. However, the formation of a long junctional epithelium was most frequently observed type of healing. Thus, the aim of this study was to examine in vitro the influence of surface conditioning of dentin by TC-HCl on human gingival epithelial cell attachment. Human gingival epithelial cells were obtained from healthy retromolar pad area(under the age 23 years). Seventy two teeth extracted from severe periodontitis were used as study material. To evaluate the epithelial cell attachment to dentin, the prepared specimen was divided to four groups. For the control group, only scaling and root planing were carried out, and for the test group, 1 to 3, the concentration of the TC-HCl was 50, 125 and 250mg/ml respectively. After cell cultivation time of 1-, 3-. 24 hour, for the indirect quantitative assessment of gingival epithelial cell attached to dentin sample, the absorbance of epithelial cell unattached to dentin was measured. The results were as follows; 1. There was no statistically significant difference between scaling and root planing group and TC-HCl 50mg/ml 125mg/ml and 250mg/ml group about absorbance of unattached epithelial cell to dentin sample(p>0.5). 2. As time passes, the absorbance of unattached gingival epithelial cell to dentin sample was decreased statistically significant(p<0.05). 3. There was no statistically significant difference among the TC-HCl group(p>0.05) We concluded that there was similar effect on gingival epithelial cell attachment between TC-HCl conditioning on root surface and only scaling and root planing treatment

• Composites Research
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• v.27 no.6
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• pp.219-224
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• 2014

Nancomposites manufacture has been developed rapidly, because of reinforcing effects of CNT in terms of mechanical, electrical and thermal properties. In this study, 10 wt% CNT paste was fabricated with good dispersion state and easy processability. Damage sensing and reinforcing effect of CNT paste were investigated in nanocomposites. 10 wt% CNT paste exhibited better tensile and flexural properties than those of general 1 wt% CNT nanocomposites. To observe the healing effect of CNT paste, a crack was made artificially with 30wt% CF30wt%/PP composites, and the CNT paste was filled inside the crack. The damage sensing of CNT paste in CF30wt%/PP composites was investigated by electrical resistance measurement and mechanical tests. CNT paste exhibited good reinforcing effect in mechanical properties of CF30wt%/PP composites, and this reinforcing effect was getting better with larger cracks. The reason was because CNT paste had good interfacial adhesion with CF30wt%/PP composites to resist crack propagation. In electrical resistance measurement, there was a jump in electrical resistance signal at the adhesion interface. The jumping signal could be used to predict fracture of CF/PP composites. CNT nanocomposites for damage sensing had crack reducing effect and damage detection using electrical resistance method.

• Archives of Plastic Surgery
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• v.46 no.6
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• pp.544-549
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• 2019

Background As the indications for postmastectomy radiotherapy expand, innovative solutions are required to reduce operative complications and reconstructive failure after prosthetic breast reconstruction. In this study, we investigated the effectiveness of acellular dermal matrix (ADM) inlay grafts in preventing postoperative wound dehiscence of irradiated breasts in the context of prosthetic breast reconstruction. Methods A retrospective analysis was conducted of 45 patients who received two-stage prosthetic reconstruction and radiotherapy following mastectomy. An ADM graft was placed beneath the incisional site during the second-stage operation in 19 patients using marionette sutures, whereas the control group did not receive the ADM reinforcement. Patient demographics and complications such as wound dehiscence, capsular contracture, peri-prosthetic infection, cellulitis, and seroma were compared between the two groups. Results During an average follow-up period of 37.1 months, wound dehiscence occurred significantly less often in the ADM-reinforced closure group (0%) than in the non-ADM group (23.1%) (P=0.032). There was no significant difference between the two groups in relation to other complications, such as capsular contracture, postoperative infection, or seroma. Conclusions The ADM inlay graft is a simple and easily reproducible technique for preventing incisional dehiscence in the setting of radiotherapy after prosthetic breast reconstruction. The ADM graft serves as a buttress to offload tension during healing and provides a mechanical barrier against pathogens. Application of this technique may serve to reduce complications in prosthetic breast reconstruction after radiotherapy.

• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.373-382
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• 2003

The successful use of osseointegrated implants to replace missing teeth has been demonstrated for both the completely and the partially edentulous patients. Many studies have confirmed an excellent long-term prognosis. The successful outcome of any implant procedure is surely dependent on the interrelationship of the various components that includes the following: biocompatibility of the implant material, macroscopic and microscopic nature of the implant surface, the status of the implant bed in both a health(noninfected) and a morphologic(bone quality) context, the surgical technique, the undisturbed healing phase, the subsequent prosthetic design, and long-term loading phase. Periodontally compromised patients have poor status of the implant bed and periodontal pathogen. No longitudinal data are available whether these factors affect the prognosis of implants. In this study, 102 machined $Br{{\aa}}nemark$ implants are inserted to analyze the success rate of 1-4 years and marginal bone loss in 49 chronic periodontitis patients. The following conclusions could be drawn from this study. 1. The cumulative success rate of implants at the 4-year of loading was 95.10%. 2. 5 failed implants have been removed. One implant have been removed due to infection, two implants were removed due to failure of osseointegration. and other two implants were removed due to mechanical failure caused by over-loading. 3. Mean marginal bone loss from the time of loading was 0.94mm at first year, 1.12mm at second year, 1.25mm at third year. These results suggest that implant therapy is good treatment modality in chronic periodontitis patients, and periodontal treatment including oral hygiene program is completed prior to insertion of implants.

• Journal of Periodontal and Implant Science
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• v.45 no.2
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• pp.46-55
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• 2015

Purpose: This study evaluated the mechanical and structural properties of biphasic calcium phosphate (BCP) blocks processed using a modified extrusion method, and assessed their in vivo effectiveness using a rabbit calvarial defect model. Methods: BCP blocks with three distinct ratios of hydroxyapatite (HA):tricalcium phosphate (TCP) were produced using a modified extrusion method:HA8 (8%:92%), HA48 (48%:52%), and HA80 (80%:20%). The blocks were examined using scanning electron microscopy, X-ray diffractometry, and a universal test machine. Four circular defects 8 mm in diameter were made in 12 rabbits. One defect in each animal served as a control, and the other three defects received the BCP blocks. The rabbits were sacrificed at either two weeks (n=6) or eight weeks (n=6) postoperatively. Results: The pore size, porosity, and compressive strength of the three types of bone block were $140-170{\mu}m$, >70%, and 4-9 MPa, respectively. Histologic and histomorphometric observations revealed that the augmented space was well maintained, but limited bone formation was observed around the defect base and defect margins. No significant differences were found in the amount of new bone formation, graft material resorption, or bone infiltration among the three types of BCP block at either of the postoperative healing points. Conclusions: Block bone substitutes with three distinct compositions (i.e., HA:TCP ratios) processed by a modified extrusion method exhibited limited osteoconductive potency, but excellent space-maintaining capability. Further investigations are required to improve the processing method.

• Journal of Periodontal and Implant Science
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• v.43 no.1
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• pp.18-23
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• 2013

Purpose: The purpose of this study was to evaluate the osseointegration of calcium phosphate (CaP)-coated implants by ion beam assisted deposition with a lack of primary stability. Methods: A total of 20 CaP-coated implants were bilaterally placed in the mandible of five dogs. In the rotational implant group, the implants were inserted in oversized drilled sockets without mechanical engagement, while the conventional surgical protocol was followed in the control group. Each group was allowed to heal for 4 and 8 weeks. The bone-to-implant contact (BIC, %) was measured by a histometric analysis. Results: All of the implants were well-maintained and healing was uneventful. In the histologic observation, all of the implants tested were successfully osseointegrated with a high level of BIC at both observation intervals. There was no significant difference in BIC among any of the groups. Conclusions: Within the limitation of this study, successful osseointegration of CaP-coated implants could be achieved in unfavorable conditions without primary stability.

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.82-89
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• 2008

Ideal rotator cuff repair is to maintain high fixation strength and minimize gap formation for optimizing the environment of biologic healing of tendon to bone. Among the current repair techniques, the suture bridge technique is superior to single- or double-row repair in ultimate load to failure, gap formation, restoring anatomical footprint and achieving pressurized contact area. The suture bridge technique also minimizes gap formation and has rotational and torsional resistances allowing early rehabilitation. However, despite superior biomechanical characteristics of the suture bridge technique, there is no evidence that these mechanical advantages result in better clinical outcomes. Furthermore, there is no difference in failure rates between the double-row repair and suture bridge techniques. An appropriate repair technique should be determined based on tear size and pattern and tendon quality.

• Clinical and Experimental Pediatrics
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• v.59 no.1
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• pp.30-34
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• 2016

Purpose: Although Bednar's aphthae are common and regress spontaneously, these lesions may lead to feeding intolerance and are often misdiagnosed, rendering examinations useless. This study sheds new light on the clinical features of Bednar's aphthae. Methods: Sixteen neonates and infants were newly diagnosed with Bednar's aphthae via routine health check-ups in an outpatient clinic. Medical records were retrospectively reviewed, and the following parameters were analyzed; sex, gestational age, birth weight, mode of delivery, and perinatal problems. A physical examination was carried out during the next outpatient visit to examine the healing process and check for the existence of scars or complications. Results: Initial presentation included changes in feeding habits (n=10), longer feeding time, reduced intake, and increased irritability. In 6 patients, Bednar's aphthae were discovered incidentally, without prior symptoms. Feeding posture and method of feeding are important causes of Bednar's aphthae. Eleven patients were fed in a horizontal position, whereas 5 patients were fed in a semiseated position. Fifteen patients were bottle-fed, whereas 1 patient was exclusively breastfed. After correcting the feeding position, the ulcerative lesions disappeared within 1 month of diagnosis. During the follow-up period, lesions did not recur in any of the patients. Conclusion: This study suggests that Bednar's aphthae are caused by mechanical pressure. A diagnosis of Bednar's aphthae should be considered when lesions are found on the palate of infants and when symptoms seem to be feeding related. Proper education of parents can both treat Bednar's aphthae and easily prevent its recurrence.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.843-848
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• 1998

Pulpotomy is a frequently used treatment modality in primary teeth. It is method by which infected coronal pulp is removed while retaining vital radicular pulp. Since its introduction in 1930 by Sweet formocresol remains the most popular medicament for this treatment. However, despite its outstanding bactericidal properties, formocresol is known to cause adverse tissue reactions. Theoretically, formocresol disinfects and fixes radicular pulp and thus prevents infection and internal resorption. In reality, however, it leads to chronic inflammation and is sometimes responsible for failures through abscess formation and internal root resorption. Also, Myers et al., in 1978, reported on the systemic distribution of FC and other studies have followed with reports of its immunological, mutagenic and carcinogenic effects. Much effort has, therefore, focused on the development of alternative medicaments and techniques. Since its introduction in 19C, ferric sulfate proven itself as an effective hemostatic agent and is used as an astringent in dentistry. In 1988, Landau and Johnsen suggested ferric sulfate be used as a medicament in pulpotomy and many studies have focused on it to overcome the toxic effects of FC. Ferric sulfate acts through its ferric ion and iron ion, which react with blood protein leading to aggregation. The aggregated protein acts to plug the blood vessels, causing mechanical hemostasis. As blood clot formation is minimal, there is reduced inflammation of radicular pulp and enhanced healing. There are no reports regarding its systemic distribution. This is a report of cases treated by the author using pulpotomy with ferric sulfate.