• Title/Summary/Keyword: study hours

Search Result 12,403, Processing Time 0.039 seconds

Quality Characteristics of Jeung-Pyun Prepared with Milk (우유 첨가에 따른 증편의 품질 선택)

  • Jang, Jung-Sun;Park, Young-Sun
    • Journal of the East Asian Society of Dietary Life
    • /
    • v.18 no.3
    • /
    • pp.311-321
    • /
    • 2008
  • In order to improve the insufficient protein content of Jeung-Pyun with respect to sitology, as well as its fermentation process, this study prepared Jeung-Pyun doughs containing 0, 5, 10, 15, and 20 g of milk, respectively, and examined their mechanical and functional characteristics. The internal structure of the Jeung-Pyun was observed by SEM. With regard to color, the L-value increased with increasing amounts of added milk, and the highest value (65.43) occurred in the group containing 20 g of added milk; however, there were no significant differences among groups. The group containing 20 g of added milk also presented the highest a-value, and the samples with added milk had higher b-values than the control. At 8 hours of fermentation, the 10 g- and 15 g-added milk groups had viscosities of 5726.67 and 6600 respectively; viscosity increased with increasing amounts of milk, and the added-milk groups had significantly higher values than the control group. Hardness also increased with increasing amounts of added milk. However, there were no significant differences in resilience and cohesive power among the groups. The groups containing 5 and 10 g of added milk had the lowest cohesion and break values. For appearance, the group without added milk had the whitest color. Pore size decreased and showed less uniformity as the amount of added milk increased. The unique tackju aroma of Jeung-Pyun decreased significantly as the level of added milk increased, and the 20 g addition presented the lowest value. The 10 g-added milk group had the highest level of sweetness, and sourness increased with increasing amounts of added milk. For softness, the control group was estimated as slightly softer than the added-milk groups. The stickiest sample was generally preferred when considering taste, white color, and sweetness. Among the quality characteristics, having greater stickiness, resilience, moisture, and softness was better in terms of chewing. Overall, the size of the Jeung-Pyun containing 10 g of milk was even and well-developed.

  • PDF

Comparison of Acute Symptoms Between a Alpine Agricultural Workers and General Workers in Gangwon-do (강원도 일부지역 고랭지 농업 농민과 일반 농업 농민의 농약중독 증상 비교)

  • Song, Jae-Seok;Park, Woong-Sub;Kwak, Yeon-Hee;Seo, Jong-Chul;Choi, Hong-Soon
    • Journal of agricultural medicine and community health
    • /
    • v.28 no.1
    • /
    • pp.29-37
    • /
    • 2003
  • Objectives: This study was performed to evaluate the pesticide exposure status and acute pesticide poisoning symtoms among agricultural workers at Gangwon-do province alpine area. Alpine area was defined as the area higher than 400m. Methods: We analyzed 257 interviwed questionnaire about pesticide exposure, acute pesticide poisoning symptoms and other variables. Results: The result was shown that agricultural workers at alpine area used more pesticide than general agricultural workers for annual usage days(35.9 days vs 14.4 days), daily usage hours(6.7 hrs vs 2.8hrs, p<0.05). But there was no difference between general and alpine agricultural worker's herbicide exposure. Moreover, the alpine agricultural worker's acute pesticide poisoning symtom score was higher than general agricultural worker's. These difference was also found at result of regression analysis, under control the age, sex, monthly income. Most frequently suffered symptom was headache and dermatological problems. The symptom prevalence of dermatological problem, headache, general weakness, eye irritation, nausea were higher among alpine agricultural workers than general agricultural workers. Conclusions: As a result, agricultural workers at alpine area were more exposed to pesticide and suffered from pesticide poisoning symptoms. To prevent the symptoms and disease from pesticide exposure among agricultural workers at alpine area, more research and political effort will be needed.

  • PDF

Effect of SO2 on NOx Removal Performance in Low Temperature Region over V2O5-Sb2O3/TiO2 SCR Catalyst Washcoated on the Metal Foam (저온영역에서 메탈폼에 코팅된 V2O5-Sb2O3/TiO2 SCR 촉매의 NOx 저감성능에 미치는 SO2 영향에 관한 연구)

  • Na, Woo-Jin;Park, Young-Jin;Bang, Hyun-Seok;Bang, Jong-Seong;Park, Hea-Kyung
    • Clean Technology
    • /
    • v.22 no.2
    • /
    • pp.132-138
    • /
    • 2016
  • The emission of SO2 is inevitable in case of combustion of most fossil fuels except LNG in commercial power plant which has a bad effect on the durability of SCR catalyst. To develop a low temperature SCR catalyst which has a high NOx removal performance and excellent durability to SO2, V2O5/TiO2 catalysts were prepared by coating on the metal foam substrate with the impregnation amount of Sb2O3 as promotor. This study has evaluated the NOx removal performance and the durability to SO2 on a laboratory scale atmospheric reactor and analyzed the properties of the prepared catalysts by means of porosimeter, BET, SEM (scanning electron microscope), EDX (energy dispersive x-ray spectrometer), XPS (X-ray photoelectron spectroscopy). It was found that the surface area of catalyst increased with the impregnation amount of Sb2O3 and the NOx removal performance showed the highest value at the 2 wt% impregnation of Sb2O3. This results was considered to be due to the optimum active site on the catalyst surface. And also, Sb2O3 impregnated catalysts presented that NOx removal performance was maintained despite the exposure to SO2 for 5 hours. Therefore it was confirmed that metal foam SCR catalyst for low temperature could be manufactured with the optimum control of Sb2O3 impregnation according to the SO2 presence or not.

Change of Pulmonary Artery Hemodynamics and Pulmonary Vascular Resistance in Experimental Pulmonary Embolism (실험적 급성 폐색전증에서 폐동맥혈역학 및 폐혈관저항의 변화)

  • Chung, Hee-Soon;Lee, Jae-Ho;Kim, Cheol-Ho
    • Tuberculosis and Respiratory Diseases
    • /
    • v.42 no.6
    • /
    • pp.913-922
    • /
    • 1995
  • Background: When we define the pressure of pulmonary vasculature in which a recruitment of blood flow occurs as $P_I$ and the proportion of change in pulmonary artery to that in cardiac output as IR and then we compare PI and IR with pulmonary vascular resistance, we would find some problems in pulmonary vascular resistance. In other words, it is the theory that, IR should be increased mainly in pulmonary embolism in which decreases the cross sectional area of pulmonary vasculature. But there are many contradictory reports resulted from various researches and the fact is known widely that any difference exists between PVR and PI, IR. For this reason, the purpose of this study is to observe how PI and IR change at the time of the outbreak and during treatment of the pulmonary embolism, and to find out the meaning of these new indicators and the difference from the pulmonary vascular resistance used generally when we subdivide the pulmonary vascular resistance into PI and IR. Method: After making AV fistula in experimental dog, we controlled cardiac output at the intervals of 15 minute in case of three kinds(all AV fistula are obstructed, only one of fistula is open and all of fistula is open), and after evoking massive pulmonary embolism with radioactive autologous blood clots, we measured the mean pulmonary artery pressure, and calculated PI and IR. We observed the pattern of change in PI and IR, without giving the control group any specific treatment and with injecting intravenously rtPA in the Group 1 and Group 2 at the dose of 1mg per kg, for 15 minutes fot the former and 3 hours for the latter. Result: 1) Pulmonary vascular resistance showed a change similar to that of pulmonary artery pressure and in all three group, PVR increased significantly, but group 1 and group 2 showed tendency that PVR keeps on decreasing after treatment, and the rate of decrease in group 1 is more rapid than group 2 significantly. 2) Both intersection(PI) and degree(IR) are proved statistically significant, in view of the straight line relationship between cardiac output and pulmonary artery pressure, calculated by minimal regression method. 3) PI changed similarly to pulmonary vascular resistance, while in the IR which is theoretically more similar to PVR, there was no significant difference or change after rtPA infusion. Conclusion: In the pulmonary embolism, Both change in IR which means real resistance of pulmonary vasculature and PI which was developed due to secondary vasoconstriction by pulmonary embolism are reflected same time.

  • PDF

Immediate Effect of Cigarette Smoking on Exercise (흡연이 운동에 미치는 단기 효과)

  • Choe, Kang-Hyeon;Choi, Cheol-Jun;Kim, Yong-Tae;Lim, Chae-Man;Koh, Youn-Suck;Kim, Woo-Sung;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
    • /
    • v.39 no.6
    • /
    • pp.511-516
    • /
    • 1992
  • Background: It is well known that cigarette smoking is the risk factor of lung cancer, chronic obstructive pulmonary disease and ischemic heart disease. But there are few reports about the immediate effect of cigarette smoking on the cardiopulmonary functions. The serum level of carbon monoxide increases during cigarette smoking. It is known that carbon monoxide increases respration rate, heart rate and cardiac output, with decrease in maximal oxygen consumption. So we have studied to determine the immediate effects of cigarette smoking on the cardiopulmonary function during exercise. Method: Thirteen healthy smoking male subjects were included in this study. Each subject was undertaken pulmonary function test and incremental exercise test on two separate days, one without smoking (control) and the other after smoking three cigarettes per hour for five hours. The order of the two tests was randomized. Results: 1) The mean age of the subjects was $25{\pm}4.9$ year-old and the mean smoking history was $6{\pm}5$ pack years. 2) The mean blood level of carbon monoxide on the smoking day was higher than that on the nonsmoking day ($5.97{\pm}1.34%$ vs. $1.45{\pm}0.83%$; p<0.01). 3) The mean maximal oxygen consumption on the smoking day was lower than that on the nonsmoking day ($2.09{\pm}0.32$ L/min vs. $2.39{\pm}0.32$ L/min; p<0.05). 4) The mean anaerobic threshold on the smoking day was lower than that on the nonsmoking day ($1.33{\pm}0.24$ L/min vs. $1.53{\pm}0.20$ L/min; p<0.05). 5) The mean heart rate at rest on the smoking day was higher than that on nonsmoking day ($84.38{\pm}11.06$ beats/min vs. $75.46{\pm}5.83$ beats/min; p<0.05). But the means of maximal heart rate on both days were not different. 6) The pulmonary function tests were similar on both days. Conclusion: There was no change in pulmonary function test, but the maximal oxygen consumption and anaerobic threshold were decreased on the smoking day. So it was concluded that cigarette smoking impaired the cardiovascular functions immediately during exercise.

  • PDF

Influence of air abrasion and different dentin sealing techniques on microtensile bond strength to dentin (상아질의 봉쇄 시기와 표면처리 방법이 미세인장 결합강도에 미치는 영향)

  • Kang, Dong-Ho;Han, Chong-Hyun;Park, Jung-Won;Kim, Sun-Jai
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.48 no.1
    • /
    • pp.8-15
    • /
    • 2010
  • Purpose: The purpose of this study was to evaluate the effect of various methods of dentin bonding agent application and air abrasion pretreatment on microtensile bond strength between dentin and resin, using a self-etching adhesive system. Material and methods: Thirty freshly extracted human molars were obtained and divided into 6 groups of 5 teeth. A 2-step self etching adhesive system (Clearfil SE Bond) was used for all groups. The control specimens were prepared using a direct immediate bonding technique. The delayed dentin sealing specimens were prepared using an indirect approach without dentin prebonding. The immediate dentin sealing specimens were prepared using dentin prebonding immediately following preparation. Immediate dentin sealing teeth and delayed dentin sealing teeth had provisional restorations using Fermit for two weeks. Then all specimens of each group were divided into two groups of three, depending on air abrasion pretreatment. Composite "crowns" were incrementally built on and specimens were stored in water for 24 hours. All teeth were prepared for a microtensile bond strength test. Bond strength data were analyzed with a one-way ANOVA test, and post hoc comparison was done using the Scheffe's test. Results: The mean microtensile bond strengths of all groups were not statistically different from each other. Conclusion: When preparing teeth for indirect restorations, IDS and DDS with Clearfil SE bond, have no difference on the microtensile bond strength between dentin and resin. Air abrasion pretreatment did not affect the microtensile bond strength when using IDS and DDS with Clearfil SE bond.

The Effect of Three Surface Sealants on Microleakage of Class V Composite Resin Restorations (복합레진으로 수복한 5급 와동의 미세누출에 대한 3종의 레진 표면 전색제의 효과)

  • Lee, Won-Cheol;Ryu, Jae-Jun
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.47 no.2
    • /
    • pp.182-190
    • /
    • 2009
  • Statement of problem: Microleakage at the occlusal and gingival margin of Class V cavities restored with composite resin has traditionally been considered an obstacle to successful restoration. Purpose: The aim of this study was to assess the effectiveness of three different surface sealants(Fortify, Permaseal and Biscover LV) on the marginal sealing of Class V light-activated composite resin restorations(Z250). Material and methods: Forty noncarious human premolars and molars extracted within a three-month period were selected. Class V cavities with the occlusal margin in enamel and gingival margin in cementum were prepared in both buccal and lingual surfaces. The teeth, randomly assigned in four groups with twenty cavities in each group, were restored with composite resin after applying an adhesive system(Clearfil SE bond). After the finishing and polishing procedures, the restorations were covered with a specific surface sealants, except for the control samples, which were not sealed. After placing restorations, the specimens were thermocycled, and immersed in a 2% methylene blue solution for twenty four hours and sectioned longitudinally. The marginal microleakage was evaluated at the occlusal and gingival interfaces using a microscope and compared among the four groups using ANOVA test and Wilcoxon Rank-Sum test($\alpha$=0.05). Results: Statistical analysis showed that there was significantly less leakage when the surface sealants were used than there was in control group(P<.05). There were no significant differences of microleakage at occlusal and gingival margins among groups. There were no significant differences between microleakage of occlusal and gingival margins in each group. Fortify was not statistically different from control group at the gingival margin(P>.05). Conclusion: Application of surface sealants was an effective method of surface coating in reducing microleakage at occlusal and gingival margins of Class V composite resin restorations. However, it is certain that some microleakage still occurred despite the application of surface sealants, especially gingival margins.

Tensile bond strength of chairside reline resin to denture bases fabricated by subtractive and additive manufacturing (적층가공과 절삭가공으로 제작한 의치상과 직접 첨상용 레진 간의 인장결합강도 비교)

  • Kim, Hyo-Seong;Jung, Ji-Hye;Bae, Ji-Myung;Kim, Jeong-Mi;Kim, Yu-Lee
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.58 no.3
    • /
    • pp.177-184
    • /
    • 2020
  • Purpose: The purpose of this study was to compare and evaluate the tensile bond strength of chairside reline resin to denture base resin fabricated by different methods (subtractive manufacturing, additive manufacturing, and conventional heat-curing). Materials and methods: Denture base specimens were fabricated as cuboid specimens with a width of 25 mm × length 25 mm × height 3 mm by subtractive manufacturing (VITA VIONIC BASE), additive manufacturing (NextDent Base) and conventional heat-curing (Lucitone 199). After storing the specimens in distilled water at 37℃ for 30 days and drying them, they were relined with polyethyl methacrylate (PEMA) chairside reline resin (REBASE II Normal). The subtractive and additive manufacturing groups were set as the experimental group, and the heat-curing group was set as the control group. Ten specimens were prepared for each group. After storing all bound specimens in distilled water at 37℃ for 24 hours, the tensile bond strength between denture bases and chairside reline resin was measured by a universal testing machine at a crosshead speed of 10 mm/min. The fracture pattern of each specimen was analyzed and classified into adhesive failure, cohesive failure, and mixed failure. Tensile bond strength, according to the fabrication method, was analyzed by 1-way ANOVA and Bonferroni's method (α=.05). Results: Mean tensile bond strength of the heat-curing group (2.45 ± 0.39 MPa) and subtractive manufacturing group (2.33 ± 0.39 MPa) had no significant difference (P>.999). The additive manufacturing group showed significantly lower tensile bond strength (1.23 ± 0.36 MPa) compared to the other groups (P<.001). Most specimens of heat-curing and subtractive manufacturing groups had mixed failure, but mixed failure and adhesive failure showed the same frequency in additive manufacturing group. Conclusion: The mean tensile bond strength of the subtractive manufacturing group was not significantly different from the heat-curing group. The additive manufacturing group showed significantly lower mean tensile bond strength than the other two groups.

COMPARISON OF MICROLEAKAGE WITH THREE DIFFERENT ADHESIVE SYSTEMS (수 종의 복합레진 접착 시스템에서의 미세 누출의 비교)

  • Seok, Choong-Ki;Nam, Dong-Woo;Nam, Soon-Hyeun;Kim, Young-Jin;Kim, Hyun-Jung
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.31 no.4
    • /
    • pp.636-644
    • /
    • 2004
  • Recently, self-etching adhesive system have been developed and bonding procedures simplified into one or two steps, which are simultaneously applied to both enamel and dentin. These systems are easy to use and have the potential for good clinical success. The purpose of this study is to evaluate in vitro the microleakage on the cementum/dentin and enamel walls in composite resin restoration of Class V cavities, regarding the use of different adhesive systems. 30 human premolars were divided into 3 groups. A standardized Class V preparation was prepared on the buccal and lingual surface of each premolar. The preparation were made parallel to the cementoenamel junctions, with the gingival half of the preparation extending 1mm apical to the cementoenamel junction. After adhesive system was applied to teeth as manufacture's recommendation, hybrid resin composite was filled in bulk into the preparation and light polymerized according to manufacturer's recommendations. Specimen were stored in distilled water at $37^{\circ}C$ for 5 days and thermocycled 1000 times ($5^{\circ}C{\pm}2^{\circ}C\;and\;55^{\circ}C{\pm}2^{\circ}C)$, then immersed in a 2% methylene blue solution for 12 hours. After sectioning mesio distally through the restorations, the degree of dye penetration was scored under a stereomicroscope at ${\times}\;25$ magnification. The data were analyzed statistically using t-test and one-way ANOVA. The results were as follows: ${\cdot}$ There is no adhesive system which can prevent microleakage perfectly. ${\cdot}$ There is significant difference in microleakage between enamel margin and dentin margin (p<0.0001). ${\cdot}$ In enamel margin, self-etching primer systems did not show any significant difference comparing total-etching system. In denin margin, self-etching primer systems did not show any significant difference comparing one-bottle adhesive system used in combination with total-etching.

  • PDF

EFFECT OF FLUORIDE IN NATURAL POLYMER ON ENAMEL DEMINERALIZATION (천연고분자 화합물을 이용한 불소겔이 법랑질 탈회에 미치는 영향)

  • Kim, Ji-Yeon;Lee, Sang-Ho;Lee, Nan-Young
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.37 no.1
    • /
    • pp.35-43
    • /
    • 2010
  • We have developed a sodium fluoride containing gelatin and methyl cellulose gel. Cariostatic abilities of those gel were investigated and compared with APF gel and fluoride varnish($Cavityshield^{TM}$). We prepared the bovine tooth samples and divided into two surface, control side and experimental side in same specimen for exclusion of difference between specimens. The experiment was consisted of 4 groups : (I) APF gel : (II) $Cavityshield^{TM}$ : (III) Gelatin F gel : (IV) Methyl cellulose F gel Decalcification were produced by placing each specimen into artificial acidic solution(pH 4.0) for 72 hours. Surface microhardness were measured and depth of demineralization lesion were measured by polarizing light microscope. The results were as follows: 1. The difference of VHN between control and experimental side is smallest in group I (p<0.05). 2. The largest difference was shown in group II (p<0.05). 3. There were no significant difference between group III and IV in microhardness test (p>0.05). 4. The difference of lesion depth is smallest in group I (p<0.05). 5. There were no significant difference between group II, III and IV in lesion depth (p>0.05). The result of the present study indicate that the fluoride containing gelatin and methyl cellulose gel is more effective than APF gel and is similar to fluoride varnish application for prevention of demineralization.