• The Korean Journal of Medicine
• /
• v.99 no.4
• /
• pp.165-168
• /
• 2024

Initiating dialysis at an advanced age is both a clinical challenge and an ethical dilemma, because the benefits in older adults with advanced chronic kidney disease may be offset by high rates of dialysis-related morbidity. Geriatric conditions, such as aging, frailty, functional impairment, and cognitive impairment, significantly influence the prognosis of elderly patients. Therefore, it becomes important to provide patients and families with prognostic information regarding timing of initiation, which is further complicated by the competing mortality risk. Shared decision-making by clinicians and patients can yield better clinical outcomes and quality of life. Through this approach, patients can opt for the most appropriate treatment based on their personal values, which often entails conservative management.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.11
• /
• pp.1465-1471
• /
• 2007

Response surface methodology (RSM) was employed to optimize extraction conditions in order to find the maximal functional properties of fluid Cheonggukjang. Based on central composite design, a study plan was established with variations of microwave power, ethanol concentration, and extraction time. Regression analysis was applied to obtain a mathematical model. The maximum inhibitory of tyrosinase activity was found as 26.75% at the conditions of 30.56W microwave power, 2.40 g/mL of ratio of solvent to sample content and 10.00 min extraction time, respectively. The maximum superoxide dismutase (SOD)-like activity was 53.23% under the extraction conditions of 108.42 W, 4.38 g/mL and 7.84 min. Based on superimposition of three dimensional RSM with respect to extraction yield, inhibitory of tyrosinase activity and SOD-like activity obtained under the various extraction conditions, the optimum ranges of extraction conditions were found to be microwave power of $55{\sim}75$ W, ratio of solvent to sample content of $2{\sim}5$ g/mL and extraction time of $3.5{\sim}15$ min, respectively.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.18 no.2
• /
• pp.167-174
• /
• 1989

AS a part of investigation to use anchovy more effectively as food source, this work was undertaken the processing conditions of extracts from rapid fermented anchovy sauce. To prepare rapid fermented products, the chopped anchovy was mixed with 50% water (w/w), and then hydrolyzed by autolysis or addition of koji under different conditions of hydrolysis. The optimal conditions for hydrolysis of chopped anchovy were revealed $50^{\circ}C$, 6 hours, pH 8.0 by autolysis, and ,$50^{\circ}C$, 6 hours, pH 7.0 by addition of 10% koji, respectively. But, pH control was not much beneficial in increasing yield. The effect of soybean protein isolote for improvement of bitter taste was also tested. The reasonable amount of added soybean protein isolate was revealed 5% on the weight basis of the chopped anchovy. The reaction mixture hydrolyzed under optimal conditions were added with 1% onion powder (w/w), 1% garlic powder(w/w) and 1% red pepper powder(w/w) for masking fishy odor, inactivated for 20 min at $100^{\circ}C$, and then centrifuged for 20 min at 4,000 rpm. The supernatant liquor was filtrated and evaporated to 50%(v/v). finally, table salt was added for bateriostatic effect and characteristic taste of rapid fermented products. the reasonable amount of added table salt was reversed 15% on the volume basis of the evaporated liquor. The hydrolysis ratio of product made by addition of water, product made by addition of koji and water, and product made by addition of soybean protein isolate, koji and water hydrolyzed under optimal conditions were 58.4%, 82.1% and 86.2%, respectively.

• Korean Journal of Food Science and Technology
• /
• v.40 no.5
• /
• pp.540-544
• /
• 2008

In this study, response surface methodology was employed in order to optimize the limonin and nomilin extraction conditions from citron seed. The independent variables were extraction temperature, extraction time, and shaking velocity. The yield of limonin and nomilin increased with increased extraction temperature and time. The extraction effects on the limonin and nomilin were higher at extraction temperature (p<0.01). The predicted extraction conditions were validated through actual experiments. The predicted conditions were as follows: $49.7^{\circ}C$ of extraction temperature, 3.3 hr of extraction time, and 400.6 rpm of shaking velocity for the maximum limonin contents (353.9 mg/100 g) and $50.3^{\circ}C$, 3.5 hr, and 399.9 rpm for the maximum nomilin contents (214.5 mg/100 g). The experimental values of limonin and nomilin contents at the predicted conditions were 338.8 and 219.5 mg/100 g, respectively. The predicted values at the optimized conditions were acceptable when compared to the experimental values.

• Korean Journal of Food Science and Technology
• /
• v.42 no.6
• /
• pp.733-738
• /
• 2010

The leaves of Zizyphus jujuba have been used for various purposes including medicine and nutrition. In this study, the conditions for the ethanol extraction of antioxidant from Zizyphus jujuba were optimized using response surface methodology (RSM). A Box-Behnken design containing 15 experimental runs with three replicates was employed to study the effects of solvent extraction conditions such as extraction temperature ($^{\circ}C$, $X_1$), extraction time (min, $X_2$), and ethanol concentration (%, $X_3$) on the extraction yield of antioxidants from Zizyphus jujuba. The yields of total polyphenols and total flavonoid, and electron donating activity (EDA) were considered as response variables. The second-order polynomial model gave a satisfactory description of the experimental results showing different patterns of extraction conditions with variation in the linear, quadratic, and interaction effects of the independent variables. Based on four-dimensional RSM, one of the optimized sets of conditions was 45% ethanol, $45^{\circ}C$, and an extraction time of 15 min. Under the optimal conditions, the predicted values were 177.64 mg/g dry basis, 35.99 mg/g dry basis, and 86.14% Vit.C equivalents for total polyphenols, total flavonoids, and EDA, respectively. The experimental values showed good agreements with the predicted values.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.5
• /
• pp.617-624
• /
• 2008

Well-designed steel moment connections will undergo local buckling before they exhaust their available rotation capacity, and inelastic post-buckling deformation plays a major role in defining the connection rotation capacity. An approximate analytical method to model strength degradation and failure of beam plastic hinges due to local buckling and estimation of the seismic rotation capacity of fully restrained beam-column connections in special steel moment-resisting frames under both monotonic and cyclic loading conditions is proposed in this study. This method is based on the plastic mechanism and a yield line plastic hinge (YLPH) model whose geometry is determined using the shapes of the buckled plastic hinges observed in experiments. The proposed YLPH model was developed for the improved WUF-W and RBS connections and validated in comparison with experimental data. The effects of the beam section geometric parameters on the rotation capacity were discussed in the companion paper (parametric studies).

• Journal of Korea Foundry Society
• /
• v.24 no.4
• /
• pp.231-237
• /
• 2004

Bake hardenable steel utilizes the phenomenon of strain aging to provide an increase in the yield strength of formed components. An increase of the carbon content will improve the bake hardening response: more solutes are available to pin mobile dislocations and to form the clusters more rapidly. But aging resistance decrease as increasing solute carbon. In order to under-stand the compatibility between bake hardenability and aging resistance. The optimum solute carbon control methods during manufacture should be determined. In this paper, the effect of continuous heat cycle conditions such as soaking temperature, rapid cooling start temperature, cooling rate on BH(Bake Hardenability), AI(Aging Index), YP-El(Yield Point Elongation) and other mechanical properties have been investigated. and following results were obtained. In the case of soaking temperature, BH increases with higher soaking temperature because of NbC $dissolution(830^{\circ}C)$, Therefore the solute carbon and BH at $850^{\circ}C$ and $870^{\circ}C$ are higher than these at $810^{\circ}C$. But BH at $870^{\circ}C$ is a little lower than that at $850^{\circ}C$ owing to the ferrite grain size. The measurement of amount of dissolution C using IFT(Internal Friction Test) can explain the relation of solute carbon and BH.

• KSBB Journal
• /
• v.23 no.4
• /
• pp.297-302
• /
• 2008

In this work, the amounts of Flavone C-glycosides homoorientin, orientin extracted from Black bamboo by various ultrasonic waves frequency (35, 72, 170 KHz, 300 Watt $\pm$1) time (15, 30, 60 min) and temperature ($25^{\circ}C$) were compared using 50% aqueous ethanol solution. And describesanalysis of the antioxidant potential of Black bamboo using an high-performance liquid chromatography (HPLC) on-line $ABTS^+$antioxidant screening method. In conjunction with the analysis of their 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid ($ABTS^+$) radical scavenging ability. The optimum operating conditions were experimentally determined to analyze the Flavone C-glycosides homoorientin, orientin in the pretreatment ultrasonic extracts. From the results, the effect on extraction yield of variations in frequency, solvent composition and extraction time was investigated. The highest yield of Black bamboo was obtained by ultrasonic waves with a frequency of 72 KHz and an extraction time of 60 min, The extraction frequency 35 KHz ($25^{\circ}C$), time 30 min was selected as an optimal antioxidant activity condition.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.22 no.1
• /
• pp.7-22
• /
• 1992

The stress distributions on a human mandible for 18 load cases under two different boundary conditions (mouth open and closed), using the three dimensional finite element modeling were studied. Also, the expected fracture loads for each load cases were calculated by using the Von-Mises yield criterion. The model of a mandible with all teeth was composed of 2402 hexahedron elements and 3698 nodes. CAD techniques were used to analyze the 3-dimensional results. The conclusions of this study were as follows: 1. In the mouth open state, the maximum stress occured at the condyle neck; when the lateral load was exerted, the maximum stress occured at the load side condyle. 2. In the mouth closed state, when the loads were exerted on the mandibular body and chin, the maximum stress occured at the loaded area, and when the loads were exerted on the angle and ramus, the maximum stress occured at the condyle neck. 3. The expected fracture loads in each load case were calculated using the Von-Mises yield criterion, and it was confirmed that the mandible in the mouth open state was more easily fractured than that in the mouth closed state, and the expected fracture loads are lesser in the cases that load direction is parallel at mandibular plane than 45°. 4. The magnitudes of the expected fracture loads increased in the order of angle, ramus, body and chin in case of the mouth closed state, while chin, body, angle and ramus in case of the mouth open state. 5. The Von-Mises stress concentration regions analyzed by F.E.M. corresponded well with the results of clinical studies.

• Journal of Hydrogen and New Energy
• /
• v.22 no.3
• /
• pp.333-339
• /
• 2011

In the present work, it was attempted to produce $H_2$ from food waste by the two-stage fermentation system. Food waste was acidified to lactate by using indigenous lactic acid bacteria under mesophilic condition, and the lactate fermentation effluent (LFE) was subsequently converted to $H_2$ by photo-fermentation. $Rhodobacter$ $sphaeroides$ KD131 was used as the photo-fermenting bacteria. The optimal conditions for lactate fermentation were found to be pH of 5.5 and substrate concentration of 30 g Carbo. COD/L, under which yielded 1.6 mol lactate/mol glucose. By filtering the LFE and adding trace metal, $H_2$ production increased by more than three times compared to using raw LFE, and finally reached the $H_2$ yield of 3.6 mol $H_2$/mol lactate. Via the developed two-stage fermentation system $H_2$ yield of 5.8 mol $H_2$/mol glucose was achieved from food waste, whose value was the highest that ever recorded.