• Journal of Food Hygiene and Safety
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• v.31 no.4
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• pp.227-249
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• 2016

Arsenic and its compounds vary in their toxicity according to the chemical forms. Inorganic arsenic is more toxic and known as carcinogen. The provisional tolerable weekly intake (PTWI) of $15{\mu}g/kg$ b.w./week established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) has been withdrawn, while the EFSA panel suggested $BMDL_{0.1}$ $0.3{\sim}8{\mu}g/kg\;b.w./day$ for cancers of the lung, skin and bladder, as well as skin lesions. Rice, seaweed and beverages are known as food being rich in inorganic arsenic. As(III) is the major form of inorganic arsenic in rice and anaerobic paddy soils, while most of inorganic arsenic in seaweed is present as As(V). The inorganic arsenic in food was extracted with solvent such as distilled water, methanol, nitric acid and so on in heat-assisted condition or at room temperature. Arsenic speciation analysis was based on ion-exchange chromatography and high-performance liquid chromatography equipped with atomic absorption spectrometry and inductively coupled plasma mass spectrometry. However, there has been no harmonized and standardized method for inorganic arsenic analysis internationally. The inorganic arsenic exposure from food has been estimated to range of $0.13{\sim}0.7{\mu}g/kg$ bw/day for European, American and Australian, and $0.22{\sim}5{\mu}g/kg$ bw/day for Asian. The maximum level (ML) for inorganic arsenic in food has established by EU, China, Australia and New Zealand, but are under review in Korea. Until now, several studies have conducted for reduction of inorganic arsenic in food. Inorganic arsenic levels in rice and seaweed were reduced by more polishing and washing, boiling and washing, respectively. Further research for international harmonization of analytical method, monitoring and risk assessment will be needed to strengthen safety management of inorganic arsenic of foods in Korea.

• Journal of Animal Environmental Science
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• v.13 no.1
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• pp.13-20
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• 2007

Sawdust biofiltration is an emerging bio-technology for control of ammonia emissions including compost odors from composting of biological wastes. Although sawdust is widely used as a medium for bulking agent in composting system and for microbial attachment in biofiltration systems, the performance of agitated bed composting and sawdust biofiltration are not well established. A pilot-scale composting of hog manure amended with sawdust and sawdust biofiltration systems for practical operation were investigated using aerated and agitated rectangular reactor with compost turner and sawdust biofilter operated under controlled conditions, each with a working capacity of approximately $40m^3\;and\;4.5m^3$ respectively. These were used to investigate the effect of compost temperature, seed germination rate and the C/N ratio of the compost on ammonia emissions, compost maturity and sawdust biofiltration performance. Temperature profiles showed that the material in three runs had been reached to temperature of 55 to $65^{\circ}C$ and above. The ammonia concentration in the exhaust gas of the sawdust biofilter media was below the maximum average value as 45 ppm. Seed germination rate levels of final compost was maintained from 70 to 93% and EC values of the finished compost varied between 2.8 and 4.8 ds/m, providing adequate conditions for plant growth.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.226-236
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• 2002

The purpose of this study was to get descriptive statistics of the contributing factors for early childhood caries and to predict the relationship of dietary, behavior factors and health status factors of the mother and child at pregnancy and after birth. 411 first caregivers of 5-year-old children in 12 kindergartens in Kangnung city were selected by stratified random cluster sampling. They were asked to fill out questionnaires and 364 of them responded. The obtained results were as follow: 1. Over the three-Fourth of children used nursing bottle or had breast feeding habit beyond the age of 1 year. 2. 8.7% of respondents didn't recognize the necessity of the preventive measures immediate after eruption of primary tooth, and only 35.1% replied that they had begun tooth cleaning. 3. Over 90% of children brush the teeth more than once per day. But over half (614%) of them brush their teeth without parents instruction. Sixty percent of children eat between the meals as often as 1-3 time(s) a day and the remainder at any times. 4. The first time of dental visit was for most children (87%) at over 3 years, recommending the earlier dental visit. Notwithstanding the rate of routine dental visit experience was relatively high(40.2%), implicating positive parents' attitude about oral health at Kangnung area. 5. The relationships between oral health state of the parents and the variables such as the timing of the first tooth cleaning, the frequency of brushing, the time of first dental visit, and the reason of first dental visit were not statistically significant. Together, there was no statistically significant difference between rural and urban area, private and public kindergarten, and boy and girl($x^2-test$, p>.05 or Fisher's exact test, p>.05).

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.522-529
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• 2000

Backgrounds : Assessment of the presence and degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. The measurement of peak expiratory flow(PEF) is a simple, fast, and cheap method to assess the severity of obstruction and its degree of reversibility. Assessing the reversibility of airflow obstruction by peak expiratory flow(PEF) measurements is practicable in general practice, but its usefulness has not been well investigated. We compared PEF and $FEV_1$ in assessing reversibility of airflow obstruction in patients with chronic obstructive pulmonary disease or asthma and developed a practical criterion for assessing the presence of reversibility in general practice. Methods : PEF measurements were performed (Spirometry) in 80 patients(aged 24-78) with a history of asthma or chronic obstructive lung disease before and after the inhalation of 200 g salbutamol. The change in PEF was compared with the change in forced expiratory volume in one second($FEV_1$). Reversible airflow obstruction was analyzed according to American Thoracic Society(ATS) criteria. Results : A 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ reversibility were observed in 45%(36) of the patients. Relative operating characteristic(ROC) analysis showed that an absolute improvement in PEF of 30 l/min gave optimal discrimination between patients with reversible and irreversible airflow obstruction(the sensitivity and specificity of an increase of 30 l/min in detecting a 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ were 72.2% and 72.7% respectively, with a positive predictive value of 68.4%). Conclusions : Absolute changes in PEF can be used to diagnose reversible airflow obstruction.

• Tuberculosis and Respiratory Diseases
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• v.50 no.4
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• pp.473-483
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• 2001

Background : There are only a few studies regarding the causes of treatment failure for tuberculosis. Therefore, this study aimed to determine the causes of intractable tuberculosis. Methods : M. tuberculosis, differentiated MOTT (Mycobacterium Other Than Tuberculosis) were isolated, and the RFLP (Restriction fragments length polymorphisms) pattern was analyzed from 204 patients with pulmonary tuberculosis and 53 suffering from neck tuberculosis. The IL-$1{\beta}$, IL-12, $^*1\;IFN{\gamma}$ and $^*2\;TNF{\alpha}$ blood levels were measured. All patients were regularly followed for 18 months after treatment. Results : There was no correlation between the RFLP patterns of M. tuberculosis treatment failure. From the 204 cases, 31.9% were intractable. The characteristics of patients with intractable tuberculosis were old age, being male and recurrent cases. The causes of treatment failure were identified as follows ; a decrease in the IL-12(59.4%) concentration, drug resistant strain(54.7%), irregular medication(15.4%), MOTT(6.2%) and a heavy infection(4.6%). The causes of all cases of intractable tuberculosis could be investigated. The IL-12 concentration in the blood was significantly lower in the intractable cases, where it disclosed a maximum sensitivity(64.7%) and specificity(75.4%) at 165.0 pg/mL. Most of the 53 cases of neck node tuberculosis were treated successfully. Therefore, we were unable to analyze the cause of treatment failure. Conclusion : A decrease in the blood IL-12 concentration and drug resistant strains were identified as the most significant causes of treatment failure for tuberculosis. In Korea, infection by clusters were prevalent, but no difference in the clinical course between clusters and non-clusters could be found.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.523-532
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• 1999

Background: With the development of the molecular biological methods, studies of the early diagnosis of lung cancer and the detection in the preneoplastic state by using genetic probes in the high risk groups are widely investigated. In lung cancer, squamous cell carcinoma is considered to progress from the normal bronchial mucosa to the preneoplastic state, and finally to the invasive carcinoma. In this study, we investigated the expression of p53 and c-erbB2 in the normal bronchi and the cancer tissues in patients with squamous cell lung cancer to evaluate the possibility of using these immunohistochemical markers as the diagnostic and prognostic parameters of patients with squamous cell lung cancer. Method: The normal and cancerous bronchial tissues of 25 patients with squamous cell carcinoma of the lung, surgically resected from May 1995 to November 1996, were immunohistochemically stained with the monoclonal antibodies to p53(DAKO-p53) and c-erbB2(phamingen 15821A) respectively. We compared the expression status of these markers between the normal bronchial mucosa and the tumor tissue, and also investigated the relationship between the expression status of these markers in tumor tissues and the pathological stage, and the survival time. Results: The pathological stage was as follows; stage I, II were found in 5 patients respectively, stage IIIA was in 8 patients, stage IIIB was in 4 patients, and stage IV was in 3 patients. The expression rate of p53 in the squamous cell lung cancer was 48%, and it was not expressed in the normal bronchial mucosa. The expression status was increased as the pathological stage advanced(p=0.0091 by test of trend). But there were no relationship between the expression of p53 and the median survival time. C-erbB2 did not yield a significantly meaningful result. Conclusion: p53 was not found in the normal bronchial mucosa, but it was expressed in 48% of the tumor tissue. And the expression rate increased as the pathological stage advanced. So it would be helpful to apply the immunochistochemical stain with p53 in the bronchial biopsy specimen in the early diagnosis trial or staging of squamous cell lung cancer.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.548-554
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• 1999

Background : Asthma is the most common respiratory crisis encountered in clinical practice, occurring in up to 4% of all pregnancies. Pregnancy often appears to alter the course of asthma. But the mechanisms responsible for variable changes in the asthma course during pregnancy remain unknown. Poor control and exacerbations of asthma during pregnancy may result in serious maternal and fetal complications. To investigate the course of asthma during pregnancy in korean women, we did a retrograde study of 27 pregnant women who had been admitted to Korea University Hospital for asthma worsened. Method: Twenty seven pregnant women who had been visited to Korea University Hospital for asthma worsened were enrolled in our retrospective study. We reviewed medical recordings and interviewed patients with asthma. Results: Twenty seven pregnant women with asthma were evaluated, and 25 patients were enrolled to our study. Two patients experienced abortions at 6 weeks and 25 weeks gestation, respectively. The period of asthma worsened was commonly during weeks 20 to 28 of gestation. And all patients wosened were improved during the last 4 weeks of pregnancy. Twenty(80%) of 25 women whose asthma worsened during pregnancy reverted toward their prepregnancy status after delivery(p<0.002). The causes of asthma worsened during pregnancy are reduction or even complete cessaton of medication due to fears about its safety(40%), worsening after upper respiratory infection (28%), and unknown(32%). There were no adverse perinatal outcomes in 25 pregnant asthma subjects. Conclusions: A major problem of therapy for asthma during pregnancy is reduction or even complete cessation of medication due to fears of fetal effects. Therefore, maternal education and optimal clinical and pharmacologic management is necessary to mitigate maternal and fetal complications.

• KDI Journal of Economic Policy
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• v.31 no.1
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• pp.169-206
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• 2009

This study stems from a question, "How should we understand the pattern of the Korean economy after the 1990s?" Among various analytic methods applicable, this study chooses a Structural Vector Autoregression (SVAR) with long-run restrictions, identifies diverse impacts that gave rise to the current status of the Korean economy, and differentiates relative contributions of those impacts. To that end, SVAR is applied to four economic models; Blanchard and Quah (1989)'s 2-variable model, its 3-variable extensions, and the two other New Keynesian type linear models modified from Stock and Watson (2002). Especially, the latter two models are devised to reflect the recent transitions in the determination of foreign exchange rate (from a fixed rate regime to a flexible rate one) as well as the monetary policy rule (from aggregate targeting to inflation targeting). When organizing the assumed results in the form of impulse response and forecasting error variance decomposition, two common denominators are found as follows. First, changes in the rate of economic growth are mainly attributable to the impact on productivity, and such trend has grown strong since the 2000s, which indicates that Korea's economic growth since the 2000s has been closely associated with its potential growth rate. Second, the magnitude or consistency of impact responses tends to have subsided since the 2000s. Given Korea's high dependence on trade, it is possible that low interest rates, low inflation, steady growth, and the economic emergence of China as a world player have helped secure capital and demand for export and import, which therefore might reduced the impact of each sector on overall economic status. Despite the fact that a diverse mixture of models and impacts has been used for analysis, always two common findings are observed in the result. Therefore, it can be concluded that the decreased rate of economic growth of Korea since 2000 appears to be on the same track as the decrease in Korea's potential growth rate. The contents of this paper are constructed as follows: The second section observes the recent trend of the economic development of Korea and related Korean articles, which might help in clearly defining the scope and analytic methodology of this study. The third section provides an analysis model to be used in this study, which is Structural VAR as mentioned above. Variables used, estimation equations, and identification conditions of impacts are explained. The fourth section reports estimation results derived by the previously introduced model, and the fifth section concludes.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.471-479
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• 2013

This study is trying to grasp the stress of the male high school students and the correlation between the stress according to the academic and economic level and oral parafunctional habits, emphasizing the need for the education of oral parafunctional habits, providing the basic data in order to accomplish correctly until the oral health of the oral maxillofacial region. From May 2013 till July 2013, a self administered survey was conducted by the selected by convenience sampling from subjects of 1, 2 grade of two high school located in Chungnam, Korea. The study results were as follow: 1) Among five areas of stress, the stress of school life was the highest as 2.11 points and the stress of home problem was the lowest as 1.51 points; 2) the stress by class showed that grade 2 was higher than grade 1 in all areas. The stress of the school life (2.21) (p<0.01), interpersonal relationship (p<0.01), and own problem (p<0.05) showed the significant difference; 3) The significance analysis results between the five areas of stress according to the stress of latent variable and the oral parafunctional habits all showed the significant difference (p<0.001). The correlation between the stress and the oral parafunctional habits showed a weak negative correlation as -0.30, and the stress of the school life, own problem, environment problem, and interpersonal relationship showed very strong correlations more than 0.7; 4) Fit measures test result of stress, academic level, and family economic level model all showed more than 0.9 in good of fit index, adjusted goodness of fit index, normed fit index and root mean square residual and root mean square error of approximation values is all estimated less than 0.1, so it showed good model. From this study, it can be concluded that there is the correlation between stress and oral parafunctional habits.

• Korean Journal of Agricultural Science
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• v.3 no.1
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• pp.121-134
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• 1976

There are many evidences that vaiious plant pathogenes were introduced with imported plants and agricultural productsrfrom foreign countries and caused heavy losses of domestic economic plants, ever since the early twentieth century when our country began to trade plants and agricultural products with foreign countries. There are many ways that foreign plant pathogenes have been introduced into our country, but the main route is considered to be imported plants and agricultural products contaminated with plant pathogenes. Plant quarantine which prevent effectively introduction of plant pathogenes from abroad was practiced for the first time in our country in 1912, and that is relatively earlier activity in the history of plant quarantine of the world. Several plant pathogenes have been introduced into our country even after plant quarantine had been practiced. Particularly for about 15 years, from the 2nd World War to 1961 when the law of Plant Protection was enacted and practical works of plant quarantine was reoperated, Korean agriculture was opened to various foreign plant pathogenes as a lapse period of plant quarantine in our country. Introduced plant pathogenes are, for the most part, from Japan because of depending upon Japan in the foreign trade of plants and agricultural products of our country. As present plant quarantine is required more exactness and rapidness, reasonable organization of quarantine system including more trained quarantine specialists, modernized facilities and introduction of improved quarantine techniques are necessary. Reasonable organization and improvement of plant quarantine system are important not only for protection of korean agriculture to plant pathogenes possible to be introduced from foreing countries, but also for increasing and stabilization of export of plants and agricultural product of our country.