• Analytical Science and Technology
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• v.25 no.6
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• pp.395-401
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• 2012

This study presents a method for the quantitative analysis of residual vinyl chloride monomer (VCM) in PVC products. In elution solvent, the extraction efficiency was similar by ethanol, THF, and acetone, but using n-hexane, it indicated relatively low extraction efficiency. Measuring VCM in the pulverized PVC samples, it showed reasonable results in both the direct injection method and headspace method with GC/MS. Regarding analysis of VCM in the intermediate sponge samples, five laboratories showed good results, and from the results, it was considered that VCM quantitative method in this study was reliable.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.282-290
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• 2018

This research was to evaluate microbial contamination levels in meat samples at hazard analysis critical control point (HACCP)-implemented processing plants that produce beef, pork, and chicken. During a period of about a year, a total of 178 samples (76 from beef, 89 from pork, and 13 from chicken) were obtained from raw materials (21.3%) and final products (78.7%). All samples were determined for each 25 g homogenized one. Samples were analyzed to determine the total aerobic plate count (APC), coliform count (CC), and E. coli count (ECC). By month, APC levels were the highest in September and the lowest in February (p<0.001). In comparison among season, APC levels in meat samples were the highest in the summer and the lowest in winter (p<0.001). By month, the highest CC prevalence was found in August, followed by October and then July (p<0.001). By season, the highest CC was obtained in summer, followed by autumn and then spring (p<0.001). All samples were negative for ECC. There was a direct correlation between the product form and coliform presence (p<0.001). In addition, there was a positive correlation between the APC and CC (r=0.261). The APCs in analyzed samples ranged from below <$10^1CFU/g$ to <$10^7CFU/g$. In conclusion, the month and season had significant effects on microbial contamination levels at HACCP implemented processing plants. Interrelationships between (i) the product form and coliform, (ii) the APC and CC were revealed.

• BMB Reports
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• v.36 no.1
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• pp.95-109
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• 2003

Inflammatory lung diseases are characterized by chronic inflammation and oxidant/antioxidant imbalance. The sources of the increased oxidative stress in patients with chronic inflammatory lung diseases such as asthma and chronic obstructive pulmonary disease (COPD) derive from the increased burden of inhaled oxidants, and from the increased amounts of reactive oxygen species (ROS) generated by several inflammatory, immune and various structural cells of the airways. Increased levels of ROS produced in the airways is reflected by increased markers of oxidative stress in the airspaces, sputum, breath, lungs and blood in patients with lung diseases. ROS, either directly or via the formation of lipid peroxidation products such as 4-hydroxy-2-nonenal may play a role in enhancing the inflammation through the activation of stress kinases (JNK, MAPK, p38) and redox sensitive transcription factors such as NF-${\kappa}B$ and AP-1. Recent evidences have indicated that oxidative stress and pro-inflammatory mediators can alter nuclear histone acetylation/deacetylation allowing access for transcription factor DNA binding leading to enhanced pro-inflammatory gene expression in various lung cells. Understanding of the mechanisms of redox signaling, NF-${\kappa}B$/AP-1 regulation, the balance between histone acetylation and deacetylation and the release and expression of pro- and anti-inflammatory mediators may lead to the development of novel therapies based on the pharmacological manipulation of antioxidants in lung inflammation and injury. Antioxidants that have effective wide spectrum activity and good bioavailability, thiols or molecules which have dual antioxidant and anti-inflammatory activity, may be potential therapeutic agents which not only protect against the direct injurious effects of oxidants, but may fundamentally alter the underlying inflammatory processes which play an important role in the pathogenesis of chronic inflammatory lung diseases.

• Tunnel and Underground Space
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• v.10 no.2
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• pp.196-210
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• 2000

This study was aimed to verify the validity of the flexural toughness evaluation method of steel fiber reinforced shotcrete(SFRS) currently being adopted by Korea Highway Corporation(KHC). Total 33 beam specimens using six different kinds of steel fiber products were prepared at tunnel construction sites and flexural toughness tests were executed at laboratory. Equivalent flexural strengths and toughness quotients were evaluated from the tests following the KHC guide iud these were compared with the quality grades determined under the guides proposed by ASTM, ITA and EFNARC. To discard the disadvantage that the toughness quotient could be influenced by flexural strength when following the KHC guide, a modification substituting the designed flexural strength for the flexural strength in the toughness quotient calculation formula was proposed to rate the quality of SFRS more adequately.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.3
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• pp.287-297
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• 2014

It is important to predict chlorine decay with different water purification processes and distribution pipeline materials, especially because chlorine decay is in direct relationship with the stability of water quality. The degree of chlorine decay may affect the water quality at the end of the pipeline: it may produce disinfection by-products or cause unpleasant odor and taste. Sand filtrate and dual media filtrate were used as influents in this study, and cast iron (CI), polyvinyl chloride (PVC), and stainless steel (SS) were used as pipeline materials. The results were analyzed via chlorine decay models by comparing the experimental and model parameters. The models were then used to estimate rechlorination time and chlorine decay time. The results indicated that water quality (e.g. organic matter and alkalinity) and pipeline materials were important factors influencing bulk decay and sand filtrate exhibited greater chlorine decay than dual media filtrate. The two-component second-order model was more applicable than the first decay model, and it enabled the estimation of chlorine decay time. These results are expected to provide the basis for modeling chlorine decay of different water purification processes and pipeline materials.

• Journal of the Korean Mathematical Society
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• v.52 no.6
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• pp.1323-1336
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• 2015

Let S be a semigroup with 0 and R be a ring with 1. We extend the definition of the zero-divisor graphs of commutative semigroups to not necessarily commutative semigroups. We define an annihilating-ideal graph of a ring as a special type of zero-divisor graph of a semigroup. We introduce two ways to define the zero-divisor graphs of semigroups. The first definition gives a directed graph ${\Gamma}$(S), and the other definition yields an undirected graph ${\overline{\Gamma}}$(S). It is shown that ${\Gamma}$(S) is not necessarily connected, but ${\overline{\Gamma}}$(S) is always connected and diam$({\overline{\Gamma}}(S)){\leq}3$. For a ring R define a directed graph ${\mathbb{APOG}}(R)$ to be equal to ${\Gamma}({\mathbb{IPO}}(R))$, where ${\mathbb{IPO}}(R)$ is a semigroup consisting of all products of two one-sided ideals of R, and define an undirected graph ${\overline{\mathbb{APOG}}}(R)$ to be equal to ${\overline{\Gamma}}({\mathbb{IPO}}(R))$. We show that R is an Artinian (resp., Noetherian) ring if and only if ${\mathbb{APOG}}(R)$ has DCC (resp., ACC) on some special subset of its vertices. Also, it is shown that ${\overline{\mathbb{APOG}}}(R)$ is a complete graph if and only if either $(D(R))^2=0,R$ is a direct product of two division rings, or R is a local ring with maximal ideal m such that ${\mathbb{IPO}}(R)=\{0,m,m^2,R\}$. Finally, we investigate the diameter and the girth of square matrix rings over commutative rings $M_{n{\times}n}(R)$ where $n{\geq} 2$.

• Journal of the Korean Society of Costume
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• v.59 no.3
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• pp.42-54
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• 2009

The purpose of the study was to grasp problems through a basic survey of actual conditions of the Korean traditional costume industry and to grope a plan to settle the problems. The results were as follows. Operating Status: Rates of the companies' establishment were reduced in 2000s and their sales were also reduced. Status of Goods Development: Korean traditional costume manufacturers and Korean traditional costume textile fabric companies had the highest rate in non-trademark production. Korean traditional costume textile fabric companies and Korean traditional costume rental companies had high rate in self-design. However, Korean traditional costume manufacturers used textile companies' catalogue with the highest rate. Status of Demand and Supply in Human Resources: In human resources needing most, Korean traditional costume manufacturers were tailors, Korean traditional costume textile fBbric companies were salespersons and Korean traditional costume rental companies were designers. Status of Management and Marketing: Causes of difficulties in management were the market slump and the spreading of products made in China. They had a direct publicity through people around mainly. Therefore, it was urgently necessary to introduce special marketing methods. In an investment plan within three years in the future, about 70% did not have an investment plan. Opinions for Promotion of Korean traditional costume: In the government's support policy they wanted, construction of social atmosphere for Korean traditional costume-wearing and Korean traditional costume related educational support had the highest rate. Most of the companies answered that specialized Korean traditional costume agencies were necessary.

• Parasites, Hosts and Diseases
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• v.46 no.2
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• pp.95-99
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• 2008

Eosinophil degranulation plays a crucial role in tissue inflammatory reactions associated with helminth parasitic infections and allergic diseases. Paragonimus westermani, a lung fluke causing human paragonimiasis, secretes a large amount of cysteine proteases, which are involved in nutrient uptake, tissue invasion, and modulation of hos's immune responses. There is, however, limited information about the response of eosinophils to direct stimulation by cysteine proteases (CP) secreted by P. westermani. In the present study, we tested whether degranulation and superoxide production from human eosinophils can be induced by stimulation of the 2 CP (27 kDa and 28 kDa) purified from excretory-secretory products (ESP) of P. westermani newly excysted metacercariae (PwNEM). A large quantity of eosinophil-derived neurotoxin (EDN) was detected in the culture supernatant when human eosinophils isolated from the peripheral blood were incubated with the purified 27 kDa CP. Furthermore, the 27 kDa CP induced superoxide anion production by eosinophils in time- and dose-dependent manners. In contrast, the purified 28 kDa CP did not induce superoxide production and degranulation. These findings suggest that the 27 kDa CP secreted by PwNEM induces superoxide production and degranulation of human eosinophils, which may be involved in eosinophil-mediated tissue inflammatory responses during the larval migration in human paragonimiasis.

• Natural Product Sciences
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• v.10 no.5
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• pp.228-236
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• 2004

The aim of the present study was to examine whether green tea extract (CUMC6335) affects the blood pressure and the isolated aortic contractility of the rabbit in comparison with one of the most powerful active catechins, epigallocatechin gallate (EGCG). The phenylephrine $(1-10\;{\mu}M)-induced$ contractile responses were greatly inhibited in the presence of CUMC6335 (0.3-1.2 mg/ml). Also, high potassium (56 mM)-induced contractile responses were depressed in high concentration (0.6-1.2 mg/ml), but not affected in low concentration CUMC6335 (0.3 mg/ml). However, epigallocatechin gallate $(EGCG,\;4-12\;{\mu}g/ml)$ did not affect the contractile responses evoked by phenylephrine and high $K^+$. The infusion of CUMC6335 with a rate of 20 mg/kg/30 min made a significant reduction in pressor responses induced by intravenous norepinephrine. However, EGCG (1 mg/kg/30 min) did not affect them. Collectively, these results obtained from the present study suggest that intravenous CUMC6335 causes depressor action in the anesthetized rat at least partly through the blockade of adrenergic ${\alpha}_1-receptors$. CUMC6335 also causes the relaxation in the isolated aortic strips of the rabbit partly via the blockade of adrenergic ${\alpha}_1-receptors$, in addition to the unknown direct mechanism. It seems that there is no species difference in the vascular effect between the rat and the rabbit.

• The Plant Pathology Journal
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• v.28 no.3
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• pp.299-305
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• 2012

Petunia hybrida is commonly used in landscapes and interiors for its attractive flower. Virus-like foliar symptoms, including a mosaic with dark green islands surrounding the veins and chlorosis on the leaf margins, were observed on a petunia plant from Icheon, Gyeonggido, Korea. Cucumber mosaic virus (CMV) was identified in the symptomatic petunia by serological testing for the presence of CMV coat protein (CP) with a direct antibody-sandwich-enzyme-linked immunosorbent assay. An agent was mechanically transmitted to indicator plant species including Chenopodium quinoa. Examination of the inoculated plant leaves by RT-PCR analysis and electron microscopy revealed the presence of specifically amplified CP products and spherical virions of approximately 28 nm in diameter, respectively, providing confirmation of a CMV infection. Analysis of CP sequences showed that CMV petunia isolate (CMVYJC) shared 82.5-100% amino acid sequence identity with CPs of representative CMV strains. Phylogenetic analysis of CPs supports that CMV-YJC is a member of CMV subgroup IA (CMV-IA) and has biological properties of CMV-IA on host species. To our knowledge, this is the first report of CMV from P. hybrida in Korea.