• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.228-234
• /
• 2016

The aim of this study was to develop pharmaceutical dosage forms with a bi-phasic drug using a double extrusion approach. Hot melt extrusion was performed using a co-rotating twin-screw extruder. The. 1st melt extrusion was performed using polymer with a relatively higher Tg, such as HPMC and the 2nd melt extrudate was obtained using the 1st extrudate and polymers with a lower Tg, such as HPMC-AS and PEO. In addition, the formulation with all the content in the same proportion as the double extudate was produced using single extrusion for comparison. Physical characterization was performed on the formulations employing differential scanning calorimetry (DSC). In vitro release tests were studied using a USP Type-I apparatus at $37{\pm}0.5^{\circ}C$ and 100 rpm. The similarity factor (f2) was also used to check the difference statistically. The DSC results indicated that the crystallinity of ibuprofen was changed to an amorphous state after extrusion in both double and single melt extrusion. Double melt extrudate with ibuprofen showed the desired release in acidic media (pH 1.2) in the first two hours and basic (pH 6.8) during six hours. Double melt extrudate with glimepiride showed faster release in 60 min of over 80%, whereas the single extrudate with glimepiride showed retarded release due to the interaction with HPMC. The similarity factor(f2) value was 28.5, which demonstrates that there were different drug release behavior between the double and single extrusion. Consequently, the double melt extrudated formulation was robust and gave the desired drug release pattern.

• The Journal of Korean Academy of Prosthodontics
• /
• v.45 no.2
• /
• pp.203-215
• /
• 2007

Statement of problem: Titanium and its alloy, with their excellent bio-compatibility and above average resistance to corrosion, have been widely used in the field of dentistry. However, the excessive oxidization of titanium which occurs during the process of firing on porcelain makes the bonding of titanium and porcelain more difficult than that of the conventional metal-porcelain bonding. To solve this problem related to titanium-porcelain bonding, several methods which modify the surfaces, coat the surfaces of titanium with various pure metals and ceramics, to enable the porcelain adhesive by limiting the diffusion of oxygen and forming the adhesive oxides surfaces, have been investigated. Purpose: The purpose of this study was to know whether the titanium-porcelain bonding strength could be enhanced by treating the titanium surface with gold and TiN followed by fabrication of clinically applicable porcelain-fused-to-titanium crown Material and method: The porcelain-fused-to-titanium crown was fabricated after sandblasting the surface of the casting titanium coping with $Al_2O_3$ and treating the surface with gold and TiN coating followed by condensation and firing of ultra-low fusing porcelain. To compare with porcelain-fused-to-titanium crowns, porcelain-fused-to-gold crowns were fabricated and used as control groups. The bonding strengths of porcelain-fused-to-gold crowns and porcelain-fused-totitanium crowns were set for comparison when the porcelain was fractured on purpose to get the experimental value of fracture strength. Then, the surface were examined by SEM and each fracturing pattern were compared with each other Result:Those results are as follows. 1. The highest value of fracture strength of porcelain-fused-to-titanium crowns was in the order of group with gold coating, group with TiN coating, group with $Al_2O_3$ sandblasting. No statistically significant difference was found among the three (P>.05). 2. The porcelain-fused-to-gold crowns showed the highest value in bonding strength. The bonding strength of crowns porcelain-fused-to-titanium crowns of rest groups showed bonding strength reaching only 85%-94% of that of PFG, though simple comparision seemed unacceptable due to the difference in materials used. 3. The fracturing patterns between metal and porcelain showed mixed type of failure behavior including cohesive failure and adhesive failure as a similar patterns by examination with the naked eye and SEM. But porcelain-fused-to-gold crowns showed high incidence of adhesive failure and porcelain-fused-to-titanium crowns showed high incidence of cohesive failure. Conclusion: Above results proved that when fabricating porcelain-fused-to-titanium crowns, treating casting titanium surface with gold or TiN was able to enhance the bonding strength between titanium and porcelain. Mean value of masticatory force was found to showed clinically acceptable values in porcelain bonding strength in all three groups. However, more experimental studies and evaluations should be done in order to get better porcelain bonding strength and various surface coating methods that can be applied on titanium surface with ease.

• Journal of Hospice and Palliative Care
• /
• v.1 no.1
• /
• pp.47-55
• /
• 1998

Background : It is almost important therapy modality to control pain for the terminal cancer patients for the last 24 hours because those terminally illed patient deserved to have pain free and peaceful time before death. Physician who is deal with terminal cancer patients for their last 24 hours does not need to worry about drug addiction or other untoward side reactions of pain medications. The purpose of this study was to evaluate if terminally illed cancer patient was given pain medication properly and sufficiently and if there was any different behavior to control pain of terminal cancer patients between medical physicians and surgeons in terms of type, amount and administration route and frequency. Methods : A retrospective chart audit of analgesic type, amount and administration route was performed on the medical recorders of 160 hospitalized terminal cancer patients who had died in the Korea University Medical Center Anam Hospital during the period of July 1, 1994 to June 30, 1995. Patients were classified into 103 patients were cared for by medical physicians and 57 patients were cared for by surgeons. After then, we analysed the difference of pain control pattern between them. Different types and amount of analgesics were converted to a common standard, an oral morphine equivalents(OME) relative to 1mg of oral morphine. Results : 1) The total number of patients was 160, male 102 cases(63.8%), and the female was 58 cases(36.2%) respectively. 2) The mean age was 56.4(${\pm}14.62$) years old and mean admission period was 27.8 days(${\pm}34.85$). 3) The frequent cancer site was stomach 42 cases(26.315), lung and liver 29 cases(18.1%) each, pancreas 10 cases(6.2%) in order 4) 125 out of 160 subjects (78.13%) complained pain, and 66 out of 103(64.08%) and 31 out of 57(54.39%) were treated with analgesics to relieve pain. 50 out of 97(51.55%) were able to continue on oral medication. 5) 86 cases(53.75%) were well oriented 24 hours prior to death. 6) The frequent analgesics for regular basis were long acting form of oral morphine 34 cases(Medical phsicians 24, Surgeons 10), intravenous morphine 26 cases(Medical physicians 20, Surgeons 6) in order, and the most common p.r.n.(pro re nata) analgesics used was intravenous morphine. 7) The mean amount of analgesics on regular basis was 115.41 OME by medical physicians and 52.7 OME by surseons(P<0.05). The mean amount of p.r.n. analgesics was significantly larger in patients are for by surgeons(66.64 OME) than medical physicians 23.49 OME(P<0.01). 8) The mean frequency of administrated number of p.r.n. analgesics was 0.62 times/day on medical part and 1.88 times/day on surgical part (P<0.001). Conclusion : Of the 97 patients with advanced cancer, 51.55% were able to take oral medications in the last day of life. The parenteral analgesics were more frequently used in the patients cared for by surgeons than medical physicians. Over the half of terminal cancer patients were well oriented in the last day of life. Doctor's knowledge and attitude towards pain is very important to mange the pain, effectively.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.51 no.4
• /
• pp.101-118
• /
• 2023

During the COVID-19 pandemic, the utilization rate of neighborhood parks and green spaces increased significantly, and the outbreak served as an opportunity to highlight the values and functions of neighborhood parks and green spaces for urban residents. This study aims to empirically analyze how citizens' movement and the use of neighborhood parks and green spaces changed before and after COVID-19 and examine the social and spatial characteristics that affected these changes. As a research method, first, people's mobility around neighborhood parks and green spaces before and after the COVID-19 pandemic were compared using signal data from telecommunication carriers. Through the analysis of changes in residence time and movement volume, the movement characteristics of citizens after COVID-19 and changes in walking-based park visits were examined. Second, the factors affecting the mobility change in neighborhood parks and green spaces were analyzed. The social and spatial characteristics that affect citizens' visits to neighborhood parks and green spaces before and after COVID-19 were examined through correlation and multiple regression analysis. Subsequently, through cluster analysis, the types of living areas for the post-COVID era were classified from the perspective of the supply and management of neighborhood parks and green spaces services, and directions for improving neighborhood parks and green spaces by type were presented. Major research findings are as follows: First, since the outbreak of COVID-19, activities within 500m of the residence have increased. The amount of stay and walking movement increased in both 2020 and 2021, which means that the need to review the quantitative standards and attractions of neighborhood parks and green spaces has increased considering the changed scope of the walking and living area. Second, the overall number of visits to neighborhood parks and green spaces by walking has increased since the outbreak of COVID-19. The number of visits to neighborhood parks and green spaces centered on the house and the workplace increased significantly. The park green policy in the post-COVID era should be promoted by discovering underprivileged areas, focusing on areas where residential, commercial, and business facilities are concentrated, and improving neighborhood parks and green services in quantitative and qualitative terms. Third, it was found that the higher the level of park green service, the higher the amount of walking movement. It is necessary to use indicators that contribute to improving citizens' actual park green services, such as walking accessibility, rather than looking at the criteria for securing green areas. Fourth, as a result of cluster analysis, five types of neighborhood parks and green spaces were derived in response to the post-COVID era. This suggests that it is necessary to consider the socioeconomic status and characteristics of living areas and the level of park green services required in future park green policies. This study has academic and policy significance in that it has laid the basis for establishing neighborhood parks and green spaces policy in response to the post-COVID era by using various analysis methodologies such as carrier signal data analysis, GIS analysis, and statistical analysis.