• 센서학회지
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• 제29권5호
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• pp.293-302
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• 2020

Food safety has emerged as a growing concern for human health in recent times. Consuming contaminated food may lead to serious health problems, and therefore, a system for monitoring food freshness that is both non-detrimental to the quality of food and highly accurate is required to ensure that only high-quality fresh food packages are provided to the customers. This paper proposes a method to monitor and detect food quality using a compact smart sensor tag. The smart tag is composed of three ultra-low-power sensors, which monitor four major indicators of food freshness: temperature, humidity, and the concentrations of ammonia and hydrogen sulfide gases. An RF energy scavenging circuit is integrated into the smart sensor tag to harvest energy from radio waves at a high frequency of 13.56 MHz to supply sufficient power to the tag. Experimental results show that the proposed energy harvester can efficiently obtain energy at a distance of approximately 40 cm from a 4 W reader. In addition, the proposed smart sensor tag can operate without any battery, thereby eliminating the requirement of frequent battery replacement and consequently decreasing the cost. Meanwhile, the freshness of preserved pork is continuously monitored under two conditions--room temperature and refrigerator temperature--both of which are the most common temperatures under which food is generally stored. The food-monitoring experiments are conducted over a period of one week using the proposed battery-less tag. Based on the experimental results, the food assessment is classified into four categories: fresh, normal, low, and spoiled.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.352-373
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• 2003

Rhamnose-rich (RROP-s) and fucose-rich (FROP-s) oligo-and polysaccharides were prepared and extensively characterised by physical and chemical procedures [1,2] and compared to L-fucose. Their biological properties were then studied on human skin fibroblast cell cultures, human skin explant cultures and on hairless rat skin, using a variety of cell-biological, biochemical and computerised morphometrical procedures. Among the most important properties we could establish, the following are of particular interest for the tretment and prevention of age-dependent modifications of human skin (loss of skin-tissue, cells and matrix, wrinkle formation and others) : stimulation of cell proliferation (by $^3$[H]-thymidine incorporation and the MTT test), scavenging of reactive oxygen species (ROS) using several different procedures, and protease (MMP-2 and MMP-9) down-regulation. A topical preparation, using RROP-s and FROP-s, and/or L-fucose, was shown to increase cell proliferation, dermal matrix synthesis, efficient scavenging of ROS-s and to increase also the thickness of dermal tissue when applied for 4 weeks on hairless rat skin, accompanied by the densification of collagen bundles as well as by an increase of elastin synthesis. Using fluorescent labeled FROPs, it could be shown that these oligosaccharides react with cell-membrane receptors and especially with the elastin-laminin-receptor and the fucose-mannose receptor, but they penetrate also in the cell nucleus, suggesting the possibility of a direct action on the regulation of gene expression. When applied to the human skin of a team of voluntary women encompassing all age-groups, the efficiency of FROP-containing preparation could be confirmed using indentometry and computerised evaluation of skin micro-relief, as well as evaluation of periorbital wrinkles. It appears therefore that these preparations correspond to all the requirements of active anti-aging principles.

• 한국식품저장유통학회지
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• 제12권2호
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• pp.130-134
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• 2005

영지버섯(Ganoderma lucidum)으로부터 영양 및 기능성 성분의 열수추출 수율을 증대시킬 수 있는 방법을 개발하기 위하여 추출 전처리 및 방법의 효과를 비교, 검토하였다. 영지를 분쇄하여 사별하고 초음파와 마이크로파 처리를 10분 동안 실시한 후 물을 용매로 상압 및 가압추출을 각각 2시간 동안 실시하였다. 추출전 전처리를 행함으로서 총당, 단백질함량 및 페놀성물질의 추출수율을 증가시켰고, 유리기 소거능이 증가하는 경향을 보였으며 마이크로파 전처리가 초음파처리 보다 우수한 것으로 나타났다. 또한 상압추출보다 가압추출에 의해 가용성 고형물, 총당, 단백질 및 페놀성 물질의 추출수율이 증대되는 경향을 보였다. 따라서 초음파나 마이크로파 전처리와 가압추출은 영지버섯의 추출효율 향상에 유효한 방법인 것으로 판단되었다.

• Fisheries and Aquatic Sciences
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• 제20권7호
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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.

• Applied Biological Chemistry
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• 제43권1호
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• pp.46-51
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• 2000

망초(Conyza bonariensis)에서 제초제 paraquat 저항성을 구명하기 위해 paraquat가 생성하는 superoxide 라디칼과 과산화수소 등의 유해 산소 물질을 제거하는 데에 관련된 효소의 활성을 저항성 종과 감수성 종의 망초에서 측정하였다. 경작지 부근에 자라는 망초는 비경작지에 자라는 망초에 비해 paraquat 저항성이 강하였다. 국내에서 paraquat를 자주 살포하는 지역에서 저항성 종의 망초가 출현하고 있음을 처음으로 보고한다. 저항성 종의 superoxide dismutase의 활성, ascorbate peroxidase의 활성, 그리고 glutathione reductase의 활성은 감수성의 그것에 비해 각각 약 20%, 44%, 그리고 64% 높게 나타났다. 이러한 결과로부터 paraquat에 대한 망초의 저항성은 superoxide dismutase, ascorbate peroxidase, 그리고 glutathione reductase 등으로 구성된 효소의 유해 산소 물질을 제거하는 효율성에 부분적으로 달려 있을 수 있다고 사료된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.261-261
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• 2007

Wearable and ubiquitous micro systems will be greatly growing and their related devices should be self-powered in order to avoid the replacement of finite power sources, for example, by scavenging energy from the environment. With ever reducing power requirements of both analog and digital circuits, power scavenging approaches are becoming increasingly realistic. One approach is to drive an electromechanical converter from ambient motion or vibration. Vibration-driven generators based on electromagnetic, electrostatic and piezoelectric technologies have been demonstrated. Among various generator types proposed so far, piezoelectric generator possesses considerable potential in micro system. To overcome low mechanical-to- electric energy conversion, the piezoelectric device should activate in resonance mode in response to external vibration. Normally, the external vibration excretes at low frequency ranging 0.1 to 200 Hz, whereas the resonant frequencies of the devices are fixed as constant. Therefore, keeping their resonant mode in varying external vibration can be one of important points in enhancing the conversion efficiency. We investigated the possibility of use of multi-bender type piezoelectric devices. To match the external vibration frequency with the device resonant frequency, the various devices with different resonant frequency were chosen. Under an external vibration acceleration of 0.1G at 120 Hz, the device exhibited a peak-to-peak voltage of 2.8 V and a power of 0.5 mw in resonance mode.

• 한국지하수토양환경학회지:지하수토양환경
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• 제23권6호
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• pp.104-113
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• 2018

A three-dimensional electrochemical process using nanosized zero-valent iron (NZVI)/activated carbon (AC) particle electrode and persulfate (PS) was developed for oxidizing pollutants. X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET) surface area analysis were performed to characterize particle electrode. XRD and SEM-EDS analysis confirmed that NZVI was impregnated on the surface of AC. Compared with the conventional two-dimensional electrochemical process, the three-dimensional particle electrode process achieved three times higher efficiency in phenol removal. The system with current density of $5mA/cm^2$ exhibited the highest phenol removal efficiency among the systems employing 1, 5, and $10mA/cm^2$. The removal efficiency of phenol increased as the Fe contents in the particle electrode increased. The particle electrode achieved more than 70% of phenol removal until it was reused for three times. The sulfate radical played a predominant role in phenol removal according to the radical scavenging test.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권1호
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• pp.45-53
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• 2021

The removal of 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution by coupled electro-oxidation and Fe(II) activated persulfate oxidation process was investigated. The electrochemical oxidation was performed using carbon sheet electrode and persulfate using Fe(II) ion as an activator. The oxidation efficiency was investigated by varying current density (2 - 10 mA/㎠), electrolyte (Na2SO4) concentration (10 - 100 mM), persulfate concentration (5 - 20 mM), and Fe(II) concentration (10 - 20 mM). The 2,4-D removal efficiency was in the order of Fe(II) activated persulfate-assisted electrochemical oxidation (Fe(II)/PS/ECO, 91%) > persulfate-electrochemical oxidation (PS/ECO, 51%) > electro-oxidation (EO, 36%). The persulfate can be activated by electron transfer in PS/ECO system, however, the addition of Fe(II) as an activator enhanced 2,4-D degradation in the Fe(II)/PS/ECO system. The 2,4-D removal efficiency was not affected by the initial pHs (3 - 9). The presence of anions (Cl- and HCO3-) inhibited the 2,4-D removal in Fe(II)/PS/ECO system due to scavenging of sulfate radical. Scavenger experiment using tert-butyl alcohol (TBA) and methanol (MeOH) confirmed that although both sulfate (SO4•-) and hydroxyl (•OH) radicals existed in Fe(II)/PS/ECO system, hydroxyl radical (SO4•-) was the predominant radical.

• 한국식품영양과학회지
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• 제45권1호
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• pp.27-34
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• 2016

본 연구에서는 마늘의 숙성 기간(15일, 30일, 60일)과 온도($60^{\circ}C$, $70^{\circ}C$)를 달리한 저온숙성마늘과 생마늘의 항산화 효과를 비교 분석하였다. DPPH와 ABTS의 라디칼 소거능과 FRAP법에 의한 환원력을 측정한 결과 $250{\mu}g/mL$에서 생마늘 추출물보다 30일 $70^{\circ}C$ 추출물과 60일 $60^{\circ}C$ 추출물의 항산화 활성이 우수하였다. 세포 내 활성산소 생성은 15일 $60^{\circ}C$ 추출물과 30일 $70^{\circ}C$ 추출물에서 높은 억제 효과를 보였으며, xanthine oxidase에 대한 활성 저해 효과 역시 15일 $60^{\circ}C$ 추출물에서 우수하였다. 항산화 효소의 유전자 발현은 LPS를 처리한 군과 생마늘 추출물보다 30일 $70^{\circ}C$ 추출물에서 높은 효과를 보였다. 본 연구 결과를 통해 저온숙성마늘이 생마늘보다 항산화 활성이 우수하다는 것을 확인함으로써 차후 항산화 건강기능식품 소재로서의 활용이 가능할 것으로 판단되나, 저온숙성마늘 추출물의 체내 생리활성 메커니즘 규명을 위해 동물실험 등의 추가적인 연구를 계속적으로 수행할 예정이다.

• 한국미생물·생명공학회지
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• 제47권1호
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• pp.64-68
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• 2019

연구는 콩 생산 산업의 부산물로 생산되는 콩잎을 고부가 식품원료로 활용하기 위해 이소플라본의 추출 효율 및 이화학적 특성 변화를 조사하였다. 열수 추출 중 온도와 시간에 따른 이소플라본 함량, DPPH 라디칼 소거능, tannin 함량, 총 폴리페놀 함량을 조사하였다. 이소플라본 함량은 $90^{\circ}C$에서 12시간 동안 추출하였을 때 $59.74{\pm}4.54mg/l$로 가장 높게 나타났으며, 12시간과 24시간 간의 유의적인 차이가 나타나지 않았다. 탄닌 함량은 낮은 온도에서 추출할수록 높은 함량을 나타내었는데, $50^{\circ}C$, 12시간에서 $0.31{\pm}0.02%$로 가장 높게 나타났다. DPPH 라디칼 소거능은 $90^{\circ}C$에서 12시간 동안 추출하였을 때, $67.26{\pm}3.67%$로 가장 높게 나타났으며, 총 폴리페놀 함량도 $1,688.68{\pm}97.37{\mu}g/ml$ CAE로 가장 우수하였다. 따라서, 이소플라본과 폴리페놀의 함량, 항산화 활성 등을 고려하여 콩잎의 열수 추출조건은 $90^{\circ}C$에서 12시간 동안 추출하는 것이 가장 효율적인 것으로 판단되었다.