• The Korean Journal of Ceramics
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• v.3 no.1
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• pp.57-61
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• 1997

The effects of pH of solution on structural, electrical, and optical properties of CdS thin films prepared by solution growth method were investigated. With increasing pH of the solution, both crystallinity and transmittance of CdS thin film were deteriorated due to impurities and CdS particles, which were produced by homogeneous nucleation and adsorbed on the surface of CdS thin films. The films were strongly adherent to substrates and has low resistivity of 10~$10^2{\omega}cm$ regrardless of deposition conditions. After annealing at 30$0^{\circ}C$ in Ar atmosphere, the resistivity decreased due to desorption of impurity ions as well as the formation of S vacancies, but after annealing above 35$0^{\circ}C$ it increased by an agglomeration of S vacancies. After annealing in air atmosphere, the film resistivity increased because of the formation of oxide particle in grain boundaries.

• Annals of Surgical Treatment and Research
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• v.95 no.5
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• pp.258-266
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• 2018

Purpose: This study analyzes the impact of laparoscopic liver resection on intra-abdominal adhesion. Methods: Patients who underwent salvage liver transplantation after liver resection for hepatocellular carcinoma from January 2012 to October 2017 at our institution were included. Information about the severity of intra-abdominal adhesions was collected from a prospectively maintained database. Intra-abdominal adhesions were graded after the agreement of 2 surgeons who participated in the salvage liver transplantation based on predetermined criteria. Adhesion severity and demographic, operative, and postoperative data were compared between the laparoscopic group and the open group. Multivariate logistic regression was performed to consider potential factors related to severe adhesion during salvage transplantation. Results: Sixty-two patients who underwent salvage liver transplantation after liver resection were included in this study. Among them, 52 patients underwent open surgery, and 10 patients underwent laparoscopy. Adhesion was significantly more severe in the open group than in the laparoscopy group (P = 0.029). A multivariate logistic regression model including potential factors related to severe adhesion showed that laparoscopy (odds ratio, 0.168; 95% confidence interval, 0.029-0.970; P = 0.048) was the only significant factor. Conclusion: Laparoscopic liver resection for hepatocellular carcinoma can minimize intra-abdominal adhesion during salvage liver transplantation.

• Archives of Craniofacial Surgery
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• v.20 no.4
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• pp.260-264
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• 2019

Dysplastic nevus is common and affects about 10% of the northern European-descendent population. Studies over the past several decades have identified dysplastic nevi as a risk factor for malignant melanoma. Furthermore, in rare cases, they confirmed that dysplastic nevi have progressed to melanoma. Cases in which dysplastic nevi progressed to malignant melanoma in multiple studies are not uncommon. A 35-year-old woman presented with the major symptom of multiple itchy brown nodules ($2.0cm{\times}1.3cm$) in the left cheek that had first appeared 20 years earlier. Complete excision was performed at the first visit; subsequent biopsy confirmed that they were dysplastic nevi. They recurred three times over 3 years at the same site, all of which were histologically diagnosed as dysplastic nevi. Five years after the final excision, a brownish nodule developed in the left cheek, with others at the left temporal region, right retroauricular region, and left shoulder at the same time. These lesions were histologically diagnosed as malignant melanoma. We experienced a case of malignant melanoma that occurred at the same site after three recurrences of dysplastic nevi. Although rare, the possibility of malignant melanoma should be considered in follow-ups in cases involving repeatedly recurrent dysplastic nevi.

• Entomological Research
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• v.48 no.6
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• pp.459-465
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• 2018

The present study evaluated the efficacy of Maxforce gel baits containing 0.01% fipronil (Maxforce), 0.05% fipronil (Maxforce Magnum), 1.0% clothianidin (Maxforce Impact), and 0.6% indoxacarb (Avion gel bait; all from Bayer Environmental Science, Clayton, CA, USA) against reference and wild strains (Mobasher, Andisheh, Tamin-e Ejtemaei, and Maskoni) of German cockroach collected in 2016. Test design and bait placement were according to World Health Organization (WHO) procedures for efficacy achieving a 95% mortality rate. Although cockroaches fed on all gel baits, gel baits containing clothianidin and indoxacarb were eaten at higher rates than gel baits containing 0.01% and 0.05% fipronil. The cumulative mortality rates reached 100% for all cockroach strains at 32, 28, 28 and 40 h after eating baits containing 0.01% fipronil, 0.05% fipronil, clothianidin, and indoxacarb, respectively. Efficacy (a 95% mortality rate) after exposure (consumption) of gel baits containing 0.05% fipronil and clothianidin was seen after 28 h, compared with 32 h for 0.01% fipronil and 40 h for indoxacarb. In conclusion, commercial gel baits have improved and may be more effective than spray formulations against German cockroaches.

• Archives of Craniofacial Surgery
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• v.22 no.3
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• pp.168-172
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• 2021

Posttraumatic pseudoaneurysm of the face is caused by blunt, penetrating, or surgical trauma. Although its incidence is low, pseudoaneurysm rupture can cause a life-threatening, massive hemorrhage. A 48-year-old man visited our emergency center due to a fall-down accident. Three-dimensional computed tomography (CT) showed a comminuted zygomaticomaxillary complex fracture of the left face. After open reduction and internal fixation, the surgical wound healed without any complications. However, the patient was readmitted 10 days after surgery due to pus-like discharge from the wound. Contrast-enhanced CT to find the abscess unexpectedly revealed a pseudoaneurysm in the left retromaxillary area. Massive oral bleeding occurred on the night of re-hospitalization and emergency surgery was done. The bleeding site was identified as a pseudo-aneurysmal rupture of the posterior superior alveolar artery in the retromaxillary area. Hemostasis was achieved by packing Vaseline gauze in the maxillary sinus using an endoscope. Delayed rupture and massive bleeding of posttraumatic retromaxillary pseudoaneurysm after a zygomaticomaxillary fracture is a low-probability, but high-impact event. Therefore, additional contrast-enhanced CT should be considered to evaluate the possibility of a posttraumatic pseudoaneurysm in cases of severe comminuted zygomaticomaxillary fracture.

• International Journal of Advanced Culture Technology
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• v.12 no.1
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• pp.209-219
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• 2024

We studied the effects of science high school students on the change of epistemological beliefs in chemistry and the academic achievement of chemistry by completing 'advanced chemistry'. For seven months from July 2023 to January 2024, 80 first-year students at G Science High School in Gyeongnam were surveyed and analyzed for epistemological beliefs about chemistry before and after classes in advanced chemistry. Chemistry academic achievement was classified by 'upper' and 'lower' levels based on the end-of-semester grades of 'advanced chemistry' in the second semester of the first year and analyzed with the SPSS 28 program. After completing advanced chemistry, the epistemological belief in chemistry increased in the proportion of favorable responses. After completing advanced chemistry, the proportion of favorable responses increased in detailed factors such as 'effort', 'math link', 'outcome', 'reality link', and 'concepts', while the 'visualization' factor decreased. Although completing 'advanced chemistry' positively changed students' epistemological beliefs about chemistry, visual expression showed little contribution to understanding chemical concepts. Based on the above results, we will have to focus on the design of instructors' teaching-learning, such as learner-centered inquiry experiments, creative visual expressions, etc., for successful chemistry teaching-learning.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.3
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• pp.225-231
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• 2008

This study evaluated whether there is a difference between a conventional titanium distraction device and a TiN-coated device in terms of implant osseointegration after horizontal distraction osteogenesis in narrow alveolar bone. Four adult mongrel dogs, each weighing $9{\sim}10kg$, were used in this study. The lower premolars were extracted and horizontal distraction was performed with conventional titanium distraction devices (group 1) or TiN-coated devices (group 2). After an 8-week consolidation period, the implants were installed, and the dogs were sacrificed after another 8 weeks. The osseointegration around the implants was evaluated histomorphologically. There was one failure in experimental group 1 because of fracture of the device. Direct bone contact was achieved and there were no significant differences between the control group and experimental groups 1 and 2 in terms of osseointegration around the implants at 8 weeks. In summary, intraoral distraction osteogenesis is a good option for augmenting severely atrophied alveolar ridges, and the TiN-coated device may be useful because of its advantages, which include surface hardness, corrosion resistance, and reduced bacteria.

• Journal of dental hygiene science
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• v.11 no.4
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• pp.375-380
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• 2011

This study evaluated whether fluoride treatment can affect recovery of the irregularity of enamel surface after tooth whitening with a high concentration of hydrogen peroxide (HP) activated by plasma arc light. A total of 36 bovine teeth stained with coke were used in this experiment. The specimens were classified into following three groups (two different commercial plasma arc groups and a control group without light curing source): (1) 35% HP gel only, (2): 35% HP gel and Plasma arc A, and (3) 35% HP gel and Plasma arc B. To measure color changes and surface morphologies before and after the bleaching, colorimeter and scanning electron microscopy were used, respectively. When the specimens were bleached with hydrogen peroxide and plasma arc lights, the bleaching effect was greater than when only hydrogen peroxide gels were used (Kruskal-Wallis test, p<0.05). In addition, plasma arc B showed the more color changes than plasma arc A (Bonferroni post-hoc test, p<0.05). The surfaces of the teeth treated with fluoride gel after the whitening treatment came to be smooth. Therefore, the results of this study suggested that the fluoride application for patients who got tooth whitening therapy with a high concentration of hydrogen peroxide gels activated by plasma arc light will be effective to recover rough enamel surfaces.

• The Journal of the Korea Contents Association
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• v.12 no.10
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• pp.216-226
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• 2012

The current study investigated delinquent school- dropout adolescents and general dropouts' differences in individual, social factors and experiences after school dropout. Data was collected through a nationwide survey(N=209) from dropout adolescents. Findings reveal that gender, age, disabilities, work experience parent cohabitation, and residential area were significant in the individual factor. Dropout time, social agency, school return experience, and GED exam pass were significant in the social factors. Groups showed differences in experiences after dropout, and self evaluation while the general group had needs for vocational education. Dropouts wanted to go back to school. Implications such as focusing on differences of each group and developing various education system and policies are needed. Limitations and implications of the study are discussed.

• Journal of Periodontal and Implant Science
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• v.37 no.3
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• pp.599-611
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• 2007

The present study was performed to evaluate the surface roughness and effect of Tetracycline-HCI on the change of implant surface microstructure according to application time. Ti$O_2$ surface Implant was utilized. Implant surface was rubbed with 50mg/ml Tetracycline-HCI solution for 0.5min, 1min, 1.5min, 2min, 2.5min and 3min respectively in the Tetracycline-HCI group. Then, specimens were measured surface roughness and processed for scanning electron microscopic observation. The results of this study were as follows. 1. Ti$O_2$ blast implant surface showed increased surface roughness 1.5 minute after treatment with Tetracycline-HCI. But, there were not significant differences in saline group after treatment. 2. Tetracycline-HCI group showed changed surface micro-morphology in SEM after 1.5 minute. There were not significant differences in saline group after treatment. 3. Between Tetracycline-HCI group and saline group, there were difference in surface roughness change and SEM micro-morphology. Tetracycline-HCI have influence on Ti$O_2$ blast implant surface. In conclusion, the detoxification with 50mg/ml Tetracycline-HCI must be applied respectively with different time according to various implant surfaces.