• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.477-488
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• 2020

Recently, foodborne illness outbreaks linked to fresh produce are being increasingly reported in the United States, the EU, and Korea as well. Some of this increase may be due to improved surveillance, increase in consumption, change in consumers' habits, and complex distribution systems. Garlic chive is a green, fresh-cut vegetable consumed year-round as a nutrition-rich herb in Korea. It is also prone to contamination with foodborne pathogens during pre-harvest, as amendment with high amounts of livestock manure or compost to soil is required in its cultivation. Our aim in this study was to evaluate microbial contamination of garlic chives, garlic chives cultivation soil, compost, and irrigation water in the southern part of Korea. Samples were collected in A, B, and C regions in 2019 and 2020, and 69, 72, 27, and 40 of garlic chives, soil, compost, and irrigated water, respectively, were analyzed for the presence of sanitary indicator bacteria (total aerobic bacteria, coliforms and Escherichia coli), Bacillus cereus, Staphylococcus aureus, pathogenic E. coli, E. coli O157:H7, Listeria monocytogenes, and Salmonella spp. In A, B, and C regions, levels of total aerobic bacteria, coliform, B. cereus, and S. aureus on all samples were between 1.14 and 8.83 log CFU/g, 0.43 and 5.01 log CFU/g, 0.41 and 5.55 log CFU/g, and 1.81 and 6.27 log CFU/g, respectively. B. cereus isolated from garlic chives and environmental samples showed β-hemolysis activity. Incidence of S. aureus in garlic chive and its production environments in 2020 was different from 2019. In this study, B. cereus and S. aureus were the only pathogenic microorganisms detected in all samples. As a result, this work suggests that continuous monitoring in the production and pre-harvest environment is required to improve hthe hygiene and safety of garlic chive.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.65-65
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• 2018

갈바륨 도금강판은 알루미늄의 우수한 차폐 특성과 내열성, 열 반사성을 가지며 아연의 희생방식 특성을 겸비하여 동일 부착량의 용융 아연도금 및 알루미늄 도금강판에 비해 우수한 내식성을 나타낸다고 알려져 있다. 또한 이것은 표면이 미려하고 경제성이 높아 건자재 용도로 현재까지도 세계적으로 널리 이용되고 있다. 여기서 지칭하는 바륨 도금강판(galvalume steel)은 아연과 알루미늄 도금강판의 장점을 접목하기 위해 55 Al-43.4 Zn-1.6 Si (wt.%)로 구성되어 개발된 3원계 성분의 합금도금강판이다. 한편, 최근에는 강재의 내식성을 향상시키기 위한 다양한 연구 결과에 의해 Zn-Al-Mg의 3원계 합금도금강판도 개발되어 사용되고 있다. 이것은 기존의 아연도금 강판 보다 10배 정도의 우수한 내식성을 나타내는 것으로 보고되고 있다. 특히, 이것은 도금된 평판부의 내식성은 물론 절단된 도금 단면부의 내식성도 매우 우수하다고 알려져 있다. 그러나 상기한 갈바륨 도금강판의 경우에는 도금된 표면부에 비해 단면부의 내식성이 상대적으로 취약한 것으로 알려져 있다. 따라서 본 연구에서는 갈바륨 도금강판의 내식성을 종합적으로 향상시키기 위하여 이 갈바륨 도금강판 상에 PVD 스퍼터링법에 의해 Mg 코팅막의 제작을 시도하였다. 여기서 Mg 코팅막은 후처리 된 갈바륨 도금강판 상에 Ar 공정압력 2 및 20 mTorr 조건 중 1.5 및 $3{\mu}m$ 두께로 제작하였다. 또한 제작한 코팅막에 대해서는 모폴로지 관찰(SEM) 및 결정구조 분석(XRD)을 하였고, 분극측정, 염수분무 시험(SST) 및 복합부식 시험(CCT)에 의해 표면 및 단면부의 내식성평가를 수행하였다. 또한 여기서는 염수분무 및 복합부식 시험 후의 시험편도 채취 하여 표면 및 단면부위에 대한 원소조성 분석(EPMA)과 결정구조 분석(XRD)을 실시하였다. 이상의 실험 결과에 의하면, 본 실험에서 제작한 Mg 코팅막은 그 두께가 두꺼울수록 표면 Mg 결정립의 크기가 증가하였고, 그 부식속도가 증가하는 경향을 나타내었다. 또한 여기서는 공정압력이 높은 조건에서 제작한 막일수록 Mg(002)면 피크 강도가 감소하고 Mg(101)면 피크의 배향성이 증가하였다. 그때 그 막의 내식성은 향상되는 경향을 나타내었다. 그리고 종합적으로 염수분무 및 복합부식 시험 결과에 의하면 Mg이 코팅된 갈바륨 도금강판은 기존 갈바륨 도금강판 보다 내식성이 현저히 향상되었다. 특히, 단면부 내식성의 경우에는 기존 대비 5배 이상 향상되는 경향을 나타내었다. 여기서 단면부 내식특성 분석을 위한 EPMA 원소조성 분석 결과에 의거하면, 부식 초기에는 마그네슘의 부식생성물에 의해 단면부가 치밀하게 보호되고 있음을 확인할 수 있었다. 그 이후에는 부식이 지속적으로 진행됨에 따라 갈바륨 도금층에서 용출된 알루미늄 및 아연 성분이 마그네슘과 함께 치밀한 부식생성물을 형성하여 단면부를 차폐함에 따라 단면부의 내식성이 크게 향상된 것으로 생각된다. 이러한 부식생성물의 결정구조 분석 결과에 따르면, 염수분무와 복합부식 시험에서는 공통적으로 MgO, $Mg(OH)_2$ 이외에도 Simonkolleite상 등이 형성되었다. 또한 건-습 반복 부식시험인 복합부식시험 후에는 $Mg_5(CO_3)_4(OH)_24H_2O$(Hydromagnesite)상 등이 형성됨을 확인할 수 있었다. 즉, 본 실험에서 후처리된 갈바륨 도금강판 상에 제작한 마그네슘 코팅막의 경우에는 상기와 같은 다양한 부식반응에 의해 표면 및 단면부에 형성된 Mg계 부식생성물과 $Zn_5(OH)_8Cl_2H_2O$(Simonkolleite)상에 의해서 표면은 물론 단면부 내식성이 크게 향상된 것으로 사료된다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.1
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• pp.1-15
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• 2016

Annual litterfall production and leaf area index (LAI, $m^2/m^2$) were estimated using litter traps in Gwangneung, Mt. Taewha and Mt. Gariwang. Annual total litter fall production including branch, bark, others was the highest in Gwangneung($7497.3{\pm}326.5kg/ha/yr$), which had the highest basal area at late successional stage, and followed by Mt. Taewha($5929.1{\pm}225.8kg/ha/yr$) and Mt. Gariwang($3,210.1{\pm}220.1kg/ha/yr$). Mt. Gariwang had the lowest litterfall production due to high elevation and short growing season even with the higher stand density and basal area than Mt. Taewha. Similarly, LAI, which was calculated by multiplying the mass of leaf litter with specific leaf area, was the highest in Gwangneung($5.99{\pm}0.69$) and followed by Mt. Taewha($5.20{\pm}0.24$) and Mt. Gariwang($4.06{\pm}0.42$) and the upper canopy species had the highest leaf area index in every sites (Gwangneung : 4.72, Mt. Taewha : 3.08, Mt. Gariwang : 2.19). However, species specific LAI estimation based on the relationship between basal area and leaf area was limited due to upper canopy species non-proportionality of basal area with LAI. In addition, the comparison between direct and indirect LAI measurement showed the importance of canopy clumping, especially at high density. Our study emphasized the necessity of direct LAI measurement using litter fall traps especially at temperate deciduous forest with diverse species.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.76-81
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• 1990

For the determination of principal taste components in L. chinensis M., A. acutiloba K., S. chinensis B. and A. sessiliflorum S., which were extracted with water and ethanol, contents and composition of free sugars, free amino acids, non-volatile organic acids and tannins were analyzed. The extraction yield of them was high when using the water as an extraction solvent, the optimal ethanol concentration with high yield was in the range of 50-75%. The contents of free amino acids in their extract $(25^{\circ}Bx)$ was high when using the ethanol as the extraction solvent. The amino acid content was in the range of 123-159 mg%. in samples. The free sugar of extracts contained 2-12% in samples which were consisted of glucose, fructose and sucrose. The pH and acidity range of extracts were 4.4-5.1 and 1.01-2.27% respectively, and especially extracts of S. chinensis B. showed to be strong acid as pH 2.9 and addity 11.93%. The composition of non-volatile organic acid in extracts of S. chinensis B. contained citric acid and malic acid 3.90% and 3.92% respectively as major components. The tannin content of extracts was considerably high when extracting with 50% ethanol, especially A. sessiliflorm S. contained $3.35%{\sim}3.85%$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.668-672
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• 2001

To investigate the oxygen free radical and alcohol metabolizing system in liver of rats fed diets with 30% ethanol extract of Lycium chinense (LCEE), Sprague-Dawley male rats weighing 225~235g have been fed a diet supplemented with 2% or 4% LCEE for a month. The rats fed LCEE supplemented diets gained less body weight compared with the control, and had no remarkable changes of liver function. In rats fed 2% LCEE supplemented diet, hepatic cytochrome P450 contents appeared to be increased, but catalase (204.88$\pm$20.06 $H_2O$$_2$nmoles/mg protein/min), and superoxide dismutase (13.18$\pm$0.74 Unit/mg protein) activities were significantly increased compared with control 120.28$\pm$26.99 $H_2O$$_2$nmoles/mg protein/min and 10.49$\pm$0.80 Units/mg protein). There was no difference in hepatic glutathione content, glutathione peroxidase, and glutathione-S-transferase ctivities between the rats fed LCEE suplemented diets and the control diet. On the other hand, hepatic alcohol dehydrogenase activity were not changed by LCEE feeding, but hepatic aldehyde dehydrogenase activities were significantly increased in rats fed both 2 and 4% LCEE diets(5.01$\pm$0.21 and 4.47$\pm$0.06 $\mu$moles NADPH/mg protein/min) compared with control (3.28$\pm$0.21 $\mu$moles NADPH/mg protein/min) and its Vmax value was 1.9 fold increased in rats fed 2% LCEE and 1.5 fold in those fed 4% LCEE compared with control. In conclusion, it is likely that rats receiving a diet supplemented with LCEE may have the oxygen free radicals and alcohol detoxication potential.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.895-906
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• 2015

This study was carried out to the structure of plant community from Sinseongam to Jungdaesa in Odaesan National Park, furthermore, it seeks to curate the basic data for planning of the Abies holophylla's forest management in Odaesan National Park. In order to identify the current ecological environment, this study explored the actual vegetation as primary research and set to twenty plots(i.e. $400m^2$) for analysing detailed structure of plant communities. The research methodology was qualitative analysis, therefore it used TWINSPAN and DCA analysis tools. Especially, TWINSPAN performed well in several comparisons of classification techniques, DCA is one of the ordination technique showed that the plant communities. The plant community was analysed classification and ordination by TWINSPAN and DCA, moreover it was analysed the structure of plant community such as importance percentage of woody species, DBH class distribution, the index of diversity and rate of sample tree growth. The main vegetation was A. holophylla-Quercus mongolica forest and Deciduous broad-leaved forest in the communities where located in low altitude and valley, whereas main vegetation where located in high altitude and slope was Q. mongolica forest. The research site's plant communities were classified four groups. In all of communities, A. holophylla was dominant species in main canopy layer, furthermore, the three communities (community I, II, III) are growing up next generation of A. holophylla excluding community IV. The communities (community I, II, III) can be sustained current status which dominates the A. holophylla communities, simultaneously, there might be expanded the Deciduous broad-leaved communities by Carpinus cordata, Betula schmidtii and so on. While, it showed that the community IV tended to be weaken the forces of A. holophylla, therefore the community IV can be transferred to C. cordata-Deciduous broad-leaved communities in the future. The age of sample trees was 79~128(i.e. A. holophylla), 75~87(i.e. Pinus koraiensis) and 190 years(i.e. Ulmus davidiana var. japonica). The index of Shannon's Species diversity (H') were ranged from 0.3889 to 1.3332 in the communities.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.259-270
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• 2020

Extreme weather events, such as heat and drought, have occurred frequently over the past two decades. This has led to continuous reports of cases of forest damage due to physiological stress, not pest damage. In 2014, pine trees were collectively damaged in the forest genetic resources reserve of Sogwang-ri, Uljin, South Korea. An investigation was launched to determine the causes of the dieback, so that a forest management plan could be prepared to deal with the current dieback, and to prevent future damage. This study aimedto 1) understand the topographic and structural characteristics of the area which experienced pine tree dieback, 2) identify the main causes of the dieback, and 3) predict future risk areas through the use of machine-learning techniques. A model for identifying risk areas was developed using 14 explanatory variables, including location, elevation, slope, and age class. When three machine-learning techniques-Decision Tree, Random Forest (RF), and Support Vector Machine (SVM) were applied to the model, RF and SVM showed higher predictability scores, with accuracies over 93%. Our analysis of the variable set showed that the topographical areas most vulnerable to pine dieback were those with high altitudes, high daily solar radiation, and limited water availability. We also found that, when it came to forest stand characteristics, pine trees with high vertical stand densities (5-15 m high) and higher age classes experienced a higher risk of dieback. The RF and SVM models predicted that 9.5% or 115 ha of the Geumgang Pine Forest are at high risk for pine dieback. Our study suggests the need for further investigation into the vulnerable areas of the Geumgang Pine Forest, and also for climate change adaptive forest management steps to protect those areas which remain undamaged.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.501-512
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• 2017

This study analyzed changes in nutrient contents of children's favorite foods between March 2010 and July 2012 after policy implementation on energy-dense and nutrient-poor (EDNP) foods based on Special Act on Safety Control of Children's Dietary Life in Korea. A total of 6,684 products in the list of children's favorite foods by the Ministry of Food and Drug Safety in March 2010 and 7,347 products in July 2012 were classified into the following three types: food products (1) manufactured or sold in 2012 as well as 2010 (n=6,174), (2) discontinued in 2012 (n=510), and (3) newly introduced in 2012 (n=1,173). Among children's favorite foods manufactured or sold in 2012 as well as 2010 (n=6,174), calories and key nutrients in sweetened ices, breads, ice creams, deep-fried noodles/noodles, ready-to-eat (RTE) foods, and pizzas were improved in comparison to those in the other food groups. However, most of the changes in calories or key nutrient contents per 100 g (or 100 mL) fell below 1 kcal or 1 g. The newly introduced candies, breads, and carbonated beverages showed slightly greater improvements in calories and key nutrient contents per 100 g (or 100 mL) than the discontinued ones in 2012. On the other hand, some negative changes were found in newly introduced chocolates and RTE foods in comparison to the discontinued ones. Overall, policy implementation on EDNP foods seemed to induce changes in nutrient contents of children's favorite foods, yet the extent of the changes was limited.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.11
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• pp.1552-1563
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• 2016

To examine the cognitive function of onion (Allium cepa L.) beverages (odourless and fortified), we analyzed in vitro neuronal cell protection against $H_2O_2$-induced cytotoxicity and performed in vivo tests on amyloid beta ($A{\beta}$)-induced cognitive dysfunction. Cellular oxidative stress and cell viability were evaluated by DCF-DA assay and MTT assay. These results show that fortified beverage resulted in better neuronal cell protection than odourless beverage at lower concentration ($0{\sim}100{\mu}g/mL$). Fortified beverage also showed more excellent acetylcholinesterase (AChE) inhibitory activity ($IC_{50}$: 4.20 mg/mL) than odourless beverage. The cognitive functions of odourless beverage and fortified beverage in $A{\beta}$-induced neurotoxicity were assessed by Y-maze, passive avoidance, and Morris water maze tests. The results show improved cognitive function in both groups treated with beverages. After in vivo tests, cholinergic activities were determined based on AChE inhibition and acetylcholine levels, and antioxidant activities were measured as SOD, oxidized glutathione (GSH)/total GSH ratio, and MDA levels in mouse brain tissue. In a Q-TOF UPLC/MS system, main compounds were analyzed as follows: odourless beverage (five types of sugars and three types of phenolics) and fortified beverages (six types of phenolics and two types of steroidal saponins).

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.195-201
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• 2003

This study was carried out to establish most suitable freezing condition, to evaluate the different condition of freezing and thawing rates on the viability and motility of frozen canine spermatozoa. The ejaculated semen was added to obtained 200∼400 ${\times}$ 10$^{6}$ /$m\ell$ with extender I and was cooled to 4$^{\circ}C$ over 30, 60 and 120 minutes. And then, semen was diluted with extender II containing 4, 6 and 8％(v/v) glycerol for 60 min, respectively and packaged in 0.5$m\ell$ straw, equilibrated far 30, 60 and 120 min at 4$^{\circ}C$ and cryopreserved in liquid nitrogen vapor at different distance(3, 5, 7 and 9 cm, respectively), plunged into nitrogen tank. Samples were thawed by placing straws into 27, 37, 47, 57$^{\circ}C$ water bath for 120, 20 and 12 sec, respectively. The results were as follows; 1. The survival and motility rate immediately post-thawing was significantly higher in samples frozen in 4％ glycerol than 6 or 8％ glycerol(P< 0.05). 2. According to equilibration time at 4$^{\circ}C$, the survival and motility rate immediately post-thawing was significantly higher in samples frozen after 60 min equilibration than 30 or 120 min equilibration(P<0.05). 3. Freezing in distance of 5 cm from liquid nitrogen yield better survival and motility rate than the others(3, 7 or 9 cm)(P<0.05). 4. The effect of thawing rate on sperm survival were higher when the thawing was done at 37$^{\circ}C$ for 120 sec(P<0.05).