• Restorative Dentistry and Endodontics
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• v.36 no.4
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• pp.280-289
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• 2011

Objectives: The purpose of this study was to evaluate ${\mu}TBS$ (microtensile bond strength) of current dentin bonding adhesives which have different hydrophobicity with low-shrinkage silorane resin. Materials and Methods: Thirty-six human third molars were used. Middle dentin was exposed. The teeth were randomly assigned to nine experimental groups: Silorane self-etch adhesives (SS), SS + phosphoric acid etching (SS + pa), Adper easy bond (AE), AE + Silorane system bonding (AE + SSb), Clearfil SE bond (CSE), CSE + SSb, All-Bond 2 (AB2), AB2 + SSb, All-Bond 3 (AB3). After adhesive's were applied, the clinical crowns were restored with Filtek LS (3M ESPE). The 0.8 mm ${\times}$ 0.8 mm sticks were submitted to a tensile load using a Micro Tensile Tester (Bisco Inc.). Water sorption was measured to estimate hydrophobicity adhesives. Results: ${\mu}TBS$ of silorane resin to 5 adhesives: SS, 23.2 MPa; CSE, 19.4 MPa; AB3, 30.3 MPa; AB2 and AE, no bond. Additional layering of SSb: CSE + SSb, 26.2 MPa; AB2 + SSb, 33.9 MPa; AE + SSb, no bond. High value of ${\mu}TBS$ was related to cohesive failure. SS showed the lowest water sorption. AE showed the highest solubility. Conclusions: The hydrophobicity of adhesive increased, and silorane resin bond-strength was also increased. Additional hydrophobic adhesive layer did not increase the bond-strength to silorane resin except AB2 + SSb. All-Bond 3 showed similar ${\mu}TBS$ & water sorption with SS. By these facts, we could reach a conclusion that All-Bond 3 is a competitive adhesive which can replace the Silorane adhesive system.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.447-457
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• 2008

Laboratory tests for single plane sliding were conducted using the model rock slope to investigate the cut slope deformability and failure mechanism due to combined effect of engineering characteristics such as angle of sliding plane, water force, joint roughness and infillings. Also the possibility of prediction of slope failure through displacement monitoring was explored. The joint roughness was prepared in forms of saw-tooth type having different roughness specifications. The infillings was maintained between upper and lower roughness plane from zero to 1.2 times of the amplitude of the surface projections. Water force was expressed as the percent filling of tension crack from dry (0%) to full (100%), and constantly increased from 0% at the rate of 0.5%/min and 1%/min upto failure. Total of 50 tests were performed at sliding angles of $30^{\circ}$ and $35^{\circ}$ based on different combinations of joint roughness, infilling thickness and water force increment conditions. For smooth sliding plane, it was found that the linear type of deformability exhibited irrespective of the infilling thickness and water force conditions. For sliding planes having roughness, stepping or exponential types of deformability were predominant under condition that the infilling thickness is lower or higher than asperity height, respectively. These arise from the fact that, once the infilling thickness exceeds asperities, strength and deformability of the sliding plane is controlled by the engineering characteristics of the infilling materials. The results obtained in this study clearly show that the water force at failure was found to increase with increasing joint roughness, and to decrease with increasing filling thickness. It seems possible to estimate failure time using the inverse velocity method for sliding plane having exponential type of deformability. However, it is necessary to estimate failure time by trial and error basis to predict failure of the slope accurately.

• Archives of design research
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• v.19 no.2 s.64
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• pp.53-62
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• 2006

E-mail has indeed developed from 'a means of instant communication' to an indispensable part of online marketing. Therefore, companies need to implement consistent customer management. Communication with customers and marketing through e-mail is a powerful way of communication and adapting one-to-one marketing strategies to customer trends, habits and taste preferences. Since setting accurate targets is especially important in the fashion industry, e-mail marketing is the most effective way to communicate with customers and one-to-one marketing constitutes a very important strategy. In this study, I will analyze this powerful one-on-one marketing tool, particularly actual e-mail messages sent by an Internet Shopping Mall from June 12 to July 30, 2005, examine the effect of these messages on sales growth and analyze actual feedback received. Regarding e-mail read rates broken down by age and gender, 1 found that females in their late twenties recorded the highest rate at 21.66% and their contribution to sales growth was recorded at 3.5% From actual sales records, found that 28.10% of total sales were attributable to people in their late twenties, showing that the age group that reads e-mails the most also buys the most. Regarding feedback by e-mail title, e-mails from the 'Casual' category seemed to be the most effective, in that most of these e-mails were read. Also, messages sent on Tuesdays were read the most, according to the feedback analysis by weekday. Section e-mails were read more often than regular e-mails. Regarding the view rate according to the time e-mails were sent, messages sent to females in their late twenties at two o'clock in the afternoon were read by 20.93% of recipients, recording the highest read rate. By offering informative content and practical tips, visitors will be attracted to the site and generate site traffic. Therefore, we can conclude that sending e-mail messages can greatly contribute to sales growth and e-mail marketing is very effective. Also, in order to make e-mail campaigns more effective and improve marketing results, we need to analyze actual results and apply our findings in future e-mail campaigns. With this, we get successful marketing results.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.159-168
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• 2003

With microtiter plate, the assay method was developed for detecting the fungicidal activity of new compounds against spore germination, spore adhesion and mycelial growth of Colletotrichum sp. JC24 cal1Sing red pepper anthracnose. Also, the effects of some commercialized fungicides on fungal development like above mentioned were investigated by measuring the optical density of mycelia grown into wells of microtiter plate. For the standardization of assay method, some factors, such as the treatment of MTT and/or propanol, inodulum density and incubation period, affecting on mycelial optical density were investigated. For obtaining precise and consistent mycelial optical density, it was necessary the treatment of MTT for 12 hrs and propanol for 1 hr. inoculum density adjusted to $1\times10^5$ spores/mL and incubation period for 36 hrs at $25^{\circ}C$. For fungicidal activities, 6 protective fungicides, 6 ones inhibiting sterol biosynthesis, and one inhibiting respiration were used in this study. While mancozeb, chlorothalonil and dithianon among 6 protective fungicides inhibited strongly spore germination, adhesion, and mycelial growth at $6.25{\mu}g/mL$, propineb, iminoctadine and fluazinam inhibited intermediately spore germination and mycelial growth at $100{\mu}g/mL$. Washing above 3 fungicides with new PD broth, their activity against spore adhesion decreased. With hexaconazole, tebuconazole and myclobutanil, the tendency of the activity against fungal differentiation of the early infection stage was similar to the latter group of protective fungicides, showing the decrease of the inhibitory activity against spore adhesion by washing 2 hrs after incubation. However, kresoxim-methyl inhibited spore adhesion distinctly, depending on the applied concentrations. Based on these results, it might be able to assess the fungicidal activity of many compounds against spore germination, adhesion and mycelial growth by the use of microtiter plate in vitro. Using the assay developed in this report, it was possible to investigate the inhibitory activity of some commercialized fungicides, too.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.545-552
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• 2015

This study One of the key elements of corporate competitiveness in the modern world of unlimited competition is human resource management. The reason that the world's leading companies are devoting a lot of investment and effort for good human resource development and management is that human resource can impact firm survival. In particular, there is little research on the internal and external environmental stimuli and job stress in the employee of small business which are often led to turnover, while they have suffered from chronic shortage of manpower. The purpose of this study is to determine the turnover factors in the small logistics companies and contribute to stable maintenance of workforce, facilitating human resource management and minimizing turnover. This study empirically analyzed the factors of the turnover in the organization of logistics companies from Busan Port, South Korea, which became one of the national infrastructure and the fifth world largest harbor. The conclusion proposed the development and direction of the human resource management which could promote the job environment improving the turnover factors and creating sustainable work condition through conducting preventive measures. The results indicated that the highest turnover rates was found in the category of field work, and the highest turnover group was from the 'less than one year', which implies that high turnover rates after and during job training might be greater cost to the companies than early turnover. The most common reasons for the high employee turnover were 'excessive workload' and 'dissatisfaction with wages'. Followed reasons including 'troubles with managers' and 'failure in organizational adaptation' can be understood in line with worse working conditions of the small logistic companies. It turned out that the preventive programs of the logistic enterprises had little effect through 'incentives system' and 'improving wage system' which are mainly conducted. The human resource managers appreciated the importance of 'wage raise' and 'benefits improvement'. This study is aimed at contributing to efficient human resource management through understanding of the turnover causes and human resource managers applying preventive measures. In particular, this can benefit small port logistics companies securing competitiveness and promoting persistent growth and development.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.424-429
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• 2009

This study aimed to assess the influence of different cross-sectional area on the cyclic fatigue fracture of Ni-Ti rotary files using a fatigue tester incorporating cyclical axial movement. Six brands of Ni-Ti rotary files (ISO 30 size with. 04 taper) of 10 each were tested: Alpha system (KOMET), HeroShaper (MicroMega), K3 (SybronEndo), Mtwo (VDW), NRT (Mani), and ProFile (Dentsply). A fatigue-tester (Denbotix) was designed to allow cyclic tension and compressive stress on the tip of the instrument. Each file was mounted on a torque controlled motor (Aseptico) using a 1:20 reduction contra-angle and was rotated at 300 rpm with a continuous, 6 mm axial oscillating motion inside an artificial steel canal. The canal had a $60^{\circ}$ angle and a 5 mm radius of curvature. Instrument fracture was visually detected and the time until fracture was recorded by a digital stop watch. The data were analyzed statistically. Fractographic analysis of all fractured surfaces was performed to determine the fracture modes using a scanning electron microscope. Cross-sectional area at 3 mm from the tip of 3 unused Ni-Ti instruments for each group was calculated using Image-Pro Plus (Imagej 1.34n, NIH). Results showed that NRT and ProFile had significantly longer time to fracture compared to the other groups (p < .05). The cross-sectional area was not significantly associated with fatigue resistance. Fractographycally, all fractured surfaces demonstrated a combination of ductile and brittle fracture. In conclusion, there was no significant relationship between fatigue resistance and the cross-sectional area of Ni-Ti instruments under experimental conditions.

• Restorative Dentistry and Endodontics
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• v.33 no.5
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• pp.472-480
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• 2008

This study was conducted to evaluate the influence of the C-factor on the bond strength of a 6th generation self-etching system by measuring the microtensile bond strength of four types of restorations classified by different C-factors with an identical depth of dentin. Eighty human molars were divided into four experimental groups, each of which had a C-factor of 0.25, 2, 3 or 4. Each group was then further divided into four subgroups based on the adhesive and composite resin used. The adhesives used for this study were AQ Bond Plus (Sun Medical, Japan) and XenoIII (DENTSPLY, Germany). And composite resins used were fantasists (Sun Medical, Japan) and Ceram-X mono (DENTSPLY, Germany). The results were then analyzed using one-way ANOVA, a Tukey's test, and a Pearson's correlation test and were as follows. 1. There was no significant difference among C-factor groups with the exception of groups of Xeno III and Ceram-X mono (p<0.05). 2. There was no significant difference between any of the adhesives and composite resins in groups with C-factor 0.25, 2 and 4. 3. There was no correlation between the change in C-factor and microtensile bond strength in the Fantasista groups. It was concluded that the C-factor of cavities does not have a significant effect on the microtensile bond strength of the restorations when cavities of the same depth of dentin are restored using composite resin in conjunction with the 6th generation self-etching system.

• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.43-48
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• 2005

An experiment was conducted to investigate the effects of mineral extract from granite on the performance, ammonia production from the litter, components of blood, Newcastle Disease (ND) titer and intestinal microflora in broiler chickens. Nine hundred sixty one-day-old broiler chickens (Ross) were assigned to five treatments: C; control, Zeolite; control + zeolite 1$\%$, AM10: control + active mineral water $10\%$ adsorbed zeolite $1\%$, AM20; control + active mineral water $20\%$ adsorbed zeolite $1\%$ and AM30; control + active mineral water $30\%$ adsorbed zeolite $1\%$. Each treatment consisted of four replicates with 48 broiler chicks for feeding trial. In order to test the effect of ND vaccine on the components of blood, ND titer and intestinal microflora, a separate group of 48 broiler chicks were assigned to the same 5 treatment as the feeding trial plus one negative control (No ND vaccine). Weight gain, feed intake, feed conversion and mortality were not significantly affected by dietary treatments but AM30 tended to be higher than other treatments in weight gain and feed intake, especially during later period (4 to 5 weeks of age). Ammonia production from the litter of AM30 treatment was significantly (P<0.01) lower than the control. Components of blood and ND titer in serum of broiler chickens were not significantly affected by treatments but MCHC (mean corpuscular hemoglobin concentration) of blood was significantly lower (P<0.05) in Zeolite treatment compared to others. The colony forming unit (CFU) of Clostridium perfringens in the small intestinal content of all zeolite and AM treated groups was significantly (P<0.01) lower than the control while the CFU of Escherichia coli was not significantly affected. The CFU of Lactobacilli in AM30 treatment was significantly (P<0.05) higher than the control. In conclusion, dietary supplement of active mineral water adsorbed to zeolite at $30\%$ level (AM30) tended to improve growth performance of broiler chickens and significantly reduced ammonia production from the litter. It also significantly increased CFU of intestinal Lactobacilli.

• Korean Journal of Poultry Science
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• v.29 no.2
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• pp.95-100
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• 2002

Two experiments were conducted to investigate the effect of taurine supplementation on lipid metabolism in laying hens. In experiment 1, 19-wk-old laying hens were given one of four taurine supplemented diets (0 (control), 0.4, 0.8, and 1.2% taurine) fur 10 weeks. Abdominal fat weight was lower in the 1.2% diet by 29.2% compared to the control. Serum concentrations of triacylglycerol and HDL-cholesterol were not different among the treatments. However, seam concentration of total cholesterol was higher by 22.4% in the 1.2% diet compared to the control. Concentration of triacylglycerol or total cholesterol in the liver were decreased by 26.1% or 26.4% and 28.2% or 26.4%, respectively in the 0.8% and 1.2% diets compared to the control. The concentration of HDL-cholesterol in liver was also lower by 33.9% in the 1.2% diet compared to the control. In experiment 2, 81-wk-old laying hens were allocated to one of three taurine supplemented diets (0 (control), 1 and 2% taurine) fur 6 weeks. Abdominal fat weight was lower by 25% in 1% taurine supplementation compared to the control. Serum concentrations of triacylglycerol, total cholesterol and HDL-cholesterol of hens fed with 1% diet were not different from those of control group. However, sew concentrations of triacylglycerol and total cholesterol were lower by 44.0% and 19.8%, respectively in the 2% diet compared to the control. Furthermore, serum concentration of HDL -cholesterol in the 2% diet was higher by 75% compared to the control. Concentrations of triacylglycerol and total cholesterol in the liver in the 2% diet were decreased in the 1% diet by 36.8 and 23%, respectively, but increased by 78.4% and 70%, respectively, compared to the control. The concentration of HDL-cholesterol in the liver was not different between the 1% diet and the control, but higher by 62.8% in the 2% diet compared to the control. These results indicated that taurine supplementation decreased the fat storage in abdominal cavity, which was accompanied by the changes in triacylglycerol and cholesterol metabolisms of laying hens.

• Journal of Chest Surgery
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• v.29 no.12
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• pp.1323-1328
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• 1996

The obstructive diseases involving the left main coronary artery(LMCA) are serious. Surgical treatment is generally regarded as much more effective than medical therapy in terms of long-term survival and relief of symptoms. This study represents an attempt to present an analysis of early surgical results in 21 cases conducted at Chonnam University Hospital between October 1992 And August 1995. The subject. 12 males and 9 female, ranged in age from 25 to 67 years with a mean age of 49.3${\pm}$12.5 years. As for indications for operation, unstable angina was reported on 66.7% of the subjects, while stable angina and acute myocardial infarction in 4 and 3 cases, respectively. There were also 2 cases of Takayasu's aortitis and 1 case of failed percutaneous translumlnal coronary angioplasty(PTCA). Eleven subjects had isolated LMCA diseases compared to 10 subjects with associated LMCA diseases. Of the patients with ass;3ciated LMCA diseases, 4 subjects had single coronary artery disease, 3 had double coronary artery disease, remaining 3 suffered from triple coronary artery disease. As for the group with isolated LMCA disease, ostidl angioplasty llsing autopericardium was conducted with 5 subjects. The remaining subjects with the isolated diseases and all of the patients with associated LMCA disease underwent aortocoronary bypass grafts. The left internal mammary artery was used in all patients and the average number of anastomoses was 3.13 ${\pm}$0.93. One subject died of low cardiac output syndrome at the second postoperative day. There were 5 instances of postoperative complication including reoperation for bleeding in two patients, wound infection in two, and arrhythmia in one. Follow-up coronary angiogram were conducted with eights patients, including five patients who underwent ostial angioplasty. In these cases, the patients showed surf. ficient enlargement of the left coronary ostium and the grafted vessels kept their patency. In our experience, surgical treatment of the LMCA diseases has not shown a higher rAte of operative mortAlity or morbidity than other obstructive coronary artery diseases. To patients with ostial stenosis, which is frequently observed among young female, angioplasly utilizing autopericardium seems to be a desirable choice considering the cosmetic effect, chances of reoperation and hemodynamic characteristics.