• Fisheries and Aquatic Sciences
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• v.20 no.7
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• pp.14.1-14.8
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• 2017

In this study, marine tunicate Styela clava hydrolysate was produced by an environment friendly and green technology, pressurized hot water hydrolysis (PHWH) at different temperatures ($125-275^{\circ}C$) and pressure 50 bar. A wide range of physico-chemical and bio-functional properties such as color, pH, protein content, total carbohydrate content, reducing sugar content, and radical scavenging activities of the produced hydrolysates were evaluated. The appearance (color) of hydrolysates varied depending on the temperature; hydrolysates obtained at $125-150^{\circ}C$ were lighter, whereas at $175^{\circ}C$ gave reddish-yellow, and $225^{\circ}C$ gave dark brown hydrolysates. The $L^*$ (lightness), $a^*$ (red-green), and $b^*$ (yellow-blue) values of the hydrolysates varied between 35.20 and 50.21, -0.28 and 9.59, and 6.45 and 28.82, respectively. The pH values of S. clava hydrolysates varied from 6.45 ($125^{\circ}C$) to 8.96 ($275^{\circ}C$) and the values were found to be increased as the temperature was increased. The hydrolysis efficiency of S. clava hydrolysate was ranged from 46.05 to 88.67% and the highest value was found at $250^{\circ}C$. The highest protein, total carbohydrate content, and reducing sugar content of the hydrolysates were found 4.52 mg/g bovine, 11.48 mg/g and 2.77 mg/g at 175, and 200 and $200^{\circ}C$, respectively. Hydrolysates obtained at lower temperature showed poor radical scavenging activity and the highest DPPH, ABTS, and FRAP activities were obtained 10.25, 14.06, and 10.91 mg trolox equivalent/g hydrolysate (dry matter basis), respectively. Therefore, S. clava hydrolysate obtained by PHWH at $225-250^{\circ}C$ and 50 bar is recommended for bio-functional food supplement preparation.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3771-3776
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• 2010

The dynamics of the $CN^-$-ligated ferric cytochrome c (CytcCN) in $D_2O$ at 283 K following Q-band photoexcitation at 575 nm was observed using femtosecond time-resolved vibrational spectroscopy. The equilibrium vibrational spectrum of the CN stretching mode of CytcCN shows two overlapping bands: one main band (82%) at $2122\;cm^{-1}$ with $23\;cm^{-1}$ full width at half maximum (fwhm) and the other band (18%) at $2116\;cm^{-1}$ with $7\;cm^{-1}$ fwhm. The time-resolved spectra show bleaching of the CN fundamental mode of CytcCN and two absorption features at lower energies. The bleach signal and both absorption features are all formed within the time resolution of the experiment (< 200 fs) and decay with a life time of 1.9 ps. One transient absorption feature, appearing immediately red to the bleach signal, results from the thermal excitation of low-frequency modes of the heme that anharmonically couple to the CN fundamental mode, thereby shifting the CN mode to lower energies. The shift of the CN mode decays with a lifetime of 2 ps, equivalent to the time scale for vibrational cooling of the low-frequency heme modes. The other transient absorption feature, which is 3.3 times weaker than the bleach signal and shifted $27\;cm^{-1}$ toward lower energies, is attributed to the CN mode in an electronically excited state where the CN bond is weakened with a lowered extinction coefficient. These observations suggest that photoexcited CytcCN mainly undergoes ultrafast radiationless relaxation, causing photo-deligation of $CN^-$ from CytcCN highly inefficient. As also observed in $CN^-$-ligated myoglobin, inefficient ligand photodissociation might be a general property of $CN^-$-ligated ferric hemes.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.906-914
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• 2020

To investigate the usefulness of natural plants, physicochemical characteristics, functional components and physiological activities of dodder(Cuscuta australis R.Brown) were experimented. The extraction of dodder was carried out at 60℃ in shaking bath with 10 times of distilled water for three hours. Harmful metals such as lead, cadmium and arsenic were not detected, but the content of mercury from dodder was 0.0004ppm in acceptable standards. The extraction yield was 23.45%, total content of phenolics equivalent to gallic acid was 699.8 mg/100g and total content of flavonoid equivalent to naringin was 373.8 mg/100g. 28 kinds of free amino acids were detected with the contents of 252mg/100g in the dodder extract, and the contents of anserine and sarcosine were analysed highest in all amino acids. From the comparison of physiological activities of dodder extract with those of ascorbic acid, total reducing power, electron donating ability based on DPPH radical scavenging and ferric reducing antioxidant power was equivalent to 88%, 56% and 40%, respectively, of ascorbic acid. The nitrite scavenging activity of dodder extract was 78% of ascorbic acid on pH 1.5, but the antioxidant index of dodder on perilla oil was about 4 times greater than that of ascorbic acid.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.2
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• pp.125-131
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• 2009

Reductive dechlorination of polychlorinated dibenzo-p-dioxins (PCDDs) and its toxicity change were predicted by the linear free energy relationship (LFER) model to assess the zero-valent iron (ZVI) and anaerobic dechlorinating bacteria (ADB) as electron donors in PCDDs dechlorination. Reductive dechlorination of PCDDs involves 256 reactions linking 76 congeners with highly variable toxicities, so is challenging to assess the overall effect of this process on the environmental impact of PCDD contamination. The Gibbs free energies of PCDDs in aqueous solution were updated to density functional theory (DFT) calculation level from thermodynamic results of literatures. All of dechlorination kinetics of PCDDs was evaluated from the linear correlation between the experimental dechlorination kinetics of PCDDs and the calculated thermodynamics of PCDDs. As a result, it was predicted that over 100 years would be taken for the complete dechlorination of octachlorinated dibenzo-p-dioxin (OCDD) to non-chlorinated compound (dibenzo-p-dioxin, DD), and the toxic equivalent quantity (TEQ) of PCDDs could increase to 10 times larger from initial TEQ with the dechlorination process. The results imply that the single reductive dechlorination using ZVI or ADB is not suitable for the treatment strategy of PCDDs contaminated soil, sediment and fly ash. This LFER approach is applicable for the prediction of dechlorination process for organohalogen compounds and for the assessment of electron donating system for treatment strategies.

• Journal of Technologic Dentistry
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• v.43 no.3
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• pp.99-105
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• 2021

Purpose: This study aims to examine the stress distribution effect of tightening torques of different abutment screws in a custom-abutment implant system on the abutment-fixture connection interface stability using finite element analysis. Methods: The custom-abutment implant system structures used in this study were designed using CATIA program. It was presumed that the abutment screws with a tightening torque of 10, 20, and 30 N·cm fixed the abutment and fixture. Furthermore, two external loadings, vertical loading and oblique loading, were applied. Results: When the screw tightening torque was 10 N·cm, the maximum stress value of the abutment screw was 287.2 MPa that is equivalent to 33% of Ti-6Al-4V yield strength. When the tightening torque was 20 N·cm, the maximum stress value of the abutment screw was 573.9 MPa that is equivalent to 65% of Ti-6Al-4V yield strength. When the tightening torque was 30 N·cm, the maximum stress value of the abutment screw was 859.6 MPa that is similar to the Ti-6Al-4V yield strength. Conclusion: As the screw preload rose when applying each tightening torque to the custom-abutment implant system, the equivalent stress increased. It was found that the tightening torque of the abutment influenced the abutment-fixture connection interface stability. The analysis results indicate that a custom-abutment implant system should closely consider the optimal tightening torque according to clinical functional loads.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.119-126
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• 2021

Radiation shielding clothing for medical institutions is used based on lead equivalent of 0.25 mmPb. However, this study intends to study the shielding suit that can guarantee the user's activity while considering the sensitivity of each part of the body. By manufacturing based on eco-friendly shielding material, it was attempted to solve the weight problem and environmental problem of existing lead aprons, and to present the same shielding performance as lead equivalent in thickness. The fabric of the produced shielding sheet was manufactured through a calendar process that adjusts the thickness of the shielding sheet from lead equivalent 0.12 mmPb to 0.32 mmPb. In addition, the usability evaluation of the manufactured shielding clothes was conducted for the subjects who were workers in medical institutions. As a result, the activity became easier and the weight was reduced by 0.26 kg. In the future, it is thought that it is necessary to improve the shielding suit design considering the activity.

• Journal of Korean Foot and Ankle Society
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• v.26 no.1
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• pp.16-21
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• 2022

When an ankle lateral malleolar fracture is accompanied by a deltoid ligament rupture without a medial malleolar fracture, such an injury is called a bimalleolar equivalent fracture. This means that even if there is no bony injury on the medial side, there may be functional instability of the ankle joint due to damage to the deltoid ligament. Manual or gravity external rotational stress radiography is used to differentiate an ankle bimalleolar equivalent fracture from an isolated lateral malleolar fracture. If the medial joint gap is widened on the stress radiography, the deltoid ligament injury can be diagnosed, and surgical treatment for fibula fractures is recommended. After open reduction of the fibula fracture (with syndesmotic fixation if needed), a decision on the repair of the deltoid ligament is taken depending on the surgeons' preference and intraoperative findings. The deltoid ligament repair is performed by inserting a suture anchor (or anchors) in the medial malleolus and fixing the deep and superficial deltoid ligaments to the medial malleolus. The only randomized study to evaluate the utility of deltoid ligament sutures in ankle fractures did not support the deltoid ligament suture, but the study itself had many limitations. An appropriately powered, randomized, controlled trial of the deltoid ligament repair with both patient-reported outcome and radiographic outcome evaluation is needed in the future.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.9
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• pp.1279-1283
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• 2009

In order to investigate the potential characteristics of horseweed (Erigeron canadensis L.) recognized with weeds for the application to food industry, the antioxidative properties of horseweed were measured with total polyphenol, flavonoid, tannin, chlorophyll contests and antioxidant activities. Total polyphenol, flavonoid, tannin, and chlorophyll content were 63.32, 27.71, 161.19, and 428.85 mg/g in the extracts of fresh horseweed (FHE), respectively. The extracts of dry horseweed (DHE) on $40^{\circ}C$ for 48 hr were 89.25, 33.44, 210.44, and 229.29 mg/g, and the extracts of dry horseweed after blanching (BDHE) were 115.49, 45.51, 252.54, and 283.07 mg/g, respectively. $IC_{50}$ of EDA (electron donating ability, %) and AEAC (L-ascorbic acid equivalent antioxidant capacity) were 5.5527 mg/mL and 192.78 mg AA eq/g sample in the FHE, respectively. The DHE were 0.4710 mg/mL and 194.05 mg AA eq/g sample, and the BDHE were 0.4135 mg/mL and 242.40 mg AA eq/g sample, respectively. Horseweed, where the antioxidant activity is excellent, is thought to be potentially useful with foodstuffs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.265-269
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• 2009

Technology development for sufficient dry matter production of Chinese milk vetch (CMV) is most important in CMV-rice cultivation system in order to provide sufficient nutrients to rice plants. However, when the CMV plants are dominated by the weed, especially Alopecurus aequalis, the CMV growth could be reduced due to light and nutrient competition. In addition, A. aequalis is potential host of the rice dwarf virus disease. Therefore, control of A. aequalis is necessary to enhance the biomass production of CMV plants when CMV stands are insufficient. The use of chemical like sethoxydim (20%, ai) showed the highest control rate of 84% at early stage and was reduced as application was delayed. A. aequalis control did not change the CMV seedling stand before and after herbicide treatment and the reseeding stand in fall was rather increased 2.2 to 2.6 times. On the other hand, in untreated control, the CMV stand at May 15 and reseeding stand in fall was significantly reduced as compared with the before herbicide treatment. Control of A. aequalis increased the CMV dry matter production by 164% for 50% CMV coverage rate and 63% for 25% CMV coverage rate. This is equivalent to $12.3{\sim}16.4\;kgN$/10a which is greater than the recommended nitrogen rate of 9kg/10a. The result indicates that the control of A. aequalis is an efficient way to enhance dry matter production in CMV-rice cultivation system especially when CMV stand is poor.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1343-1349
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• 2017

This study was carried out to determine the simultaneous extraction conditions of functional components (lutein, ${\beta}$-carotene, total polyphenol, flavonoids, and phenolic compounds) from sweet potato leaves and to evaluate the antioxidant activities. Extraction conditions included different ethanol concentrations (1st extraction: 99.9% ethanol; 2nd extraction: 50~90% ethanol) and times (30, 60, and 90 min). The highest values of lutein and ${\beta}$-carotene content were obtained by the 2nd extraction at an ethanol concentration of 90%. The extraction yields of lutein and ${\beta}$-carotene decreased with increasing extraction time. The maximum polyphenol, flavonoid, and total phenolic acid contents and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities were 32.3 mg gallic acid equivalent/g, 17.0 mg catechin equivalent/g, 2,842.6 mg/100 g, 17.0 mg ascorbic acid equivalent/g, and 1.94 mg/mL ($IC_{50}$) at the 2nd extraction with an ethanol concentration of 60%. The optimum extraction conditions were as follows; ethanol concentrations of the extraction solvent were 99.9% (1st extraction) and 60% (2nd extraction), and extraction time was 30 min.