• Title/Summary/Keyword: 건강학

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The Effect of Sodium Chloride on the Quality of Cheese and Upcoming Technologies for Manufacturing Reduced-Sodium Cheeses: A Review (Sodium Chloride가 치즈의 품질에 미치는 영향과 저염치즈 개발 기술: 총설)

  • Chon, Jung-Whan;Kim, Hyun-Sook;Kim, Dong-Hyeon;Kim, Hong-Seok;Song, Kwang-Young;Jeong, Dong-Gwan;Kim, Soo-Ki;Seo, Kun-Ho
    • Journal of Dairy Science and Biotechnology
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    • v.33 no.1
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    • pp.47-57
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    • 2015
  • Sodium is an essential nutrient with very important functions, including regulation of the extracellular fluid volume and active transport of molecules across the cell membranes. Since high levels of dietary sodium are associated with a high prevalence of hypertension, prehypertension, and other adverse effects on health, many national and international health organizations (WHO, FAO, etc.) recommend that sodium intake should be significantly decreased. In developed nations, cheese products, from among many processed foods, can cause high salt intake. Hence, there is an urgent need to reduce the content of salt in cheese processing, using various substitutes of sodium chloride (NaCl). In general, salt (NaCl) has been used as a food preservative to limit and (or) kill the growth of foodborne pathogens and spoilage organisms by decreasing the water activity, and to improve texture and flavor. To maintain public health, the salt content in cheese should be decreased without influencing the physicochemical properties of cheese. Therefore, the objective of this review is to outline the upcoming technologies used to reduce the salt content in different types of cheese using various substitutes.

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A Study on Decision-Making Processes of Organic Foods (무공해식품의 구매의사결정에 관한 연구)

  • NamKung, Sok
    • Journal of the Korean Society of Food Culture
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    • v.9 no.4
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    • pp.379-394
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    • 1994
  • The purpose of this study was to identify the correlation between the factors influencing on housewives' decision-making processes of organic foods and the relating variables, and the 5 stages of decision-making processes of the EBK model is utilized in this study. The sample was selected from 411 housewives living in Seoul from 1st of September through 20th of September, 1993. Frequency, Percentage, Mean, Factor analysis, One-way ANOVA, Duncan's multiple range test, t-Test, Correlation, Multiple regression analysis and Path analysis were measured. Major results are as follows: 1. Purchasing motivation of the organic foods were in order of the health care, nutritive value and taste care. 2. The major informations source for the knowledge of organic foods were in order of TV/radio, newspaper/magazine, recommendations informations and advice through a family/friends/acquaintances. 3. Evalution criteria in shopping of organic foods, the total degree of consideration over the purchasing factors of organic foods was fairly high level: consumers thought much of the sanitation/freshness, nutritive value and the food safety. In this regard opinion leaders was dominantly mass media. Consumers have a tendency to purchase organic foods in consideration of their children and husband. 4. Major place to purchase organic foods are super markets and department stores. And When shopping organic foods, housewives by all means confirm the check points in their own mind, which were expiry date, manufactured date and packing condition, but unexpectedly manufactured company was out of concern. 5. Housewives usually satisfy with decision after purchasing organic foods, while they were fairly unsatisfied with the price, quality, incomplete description for ingredients and manufactured date. 6. The variables influencing to the sincerity when selecting the most desired organic foods is how be cares about the natural freshness of the foods and the types of residents in order. Another interesting tendency is the richer they are very considerate to decide. It is to say the people who cares more about the natural freshness is the sincerer when making decision and also the class who lives in the apartment house enjoying high income do not easily accept the product quality.

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Effects of Dietary Resveratrol on Growth Performance, Blood Biochemical Parameter, Immunoglobulin, and Blood Antioxidant Activity in Broiler Chicks (Resveratrol의 첨가가 육계의 생산성, 혈액 생화학 특성, 혈액 내 면역글로불린과 혈액 내 항산화 인자에 미치는 영향)

  • Kim, Dong-Wook;Hong, Eui-Chul;Ji, Sang-Yoon;Lee, Wang-Shik;Bang, Han-Tae;Kang, Hwan-Ku;Kim, Hyun-Soo;Kim, Sang-Ho
    • Korean Journal of Poultry Science
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    • v.42 no.2
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    • pp.147-156
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    • 2015
  • This study was conducted to investigate the effects of dietary resveratrol on growth performance, blood biochemical parameters, immunoglobulin, and blood antioxidant activity in broiler chicks. Three hundred twenty one-day old broiler chicks were divided 8 treatments (C(-), basal diet; C(+), basal diet with antibiotics; DL-${\alpha}$-tocopherol 20 IU; DL-${\alpha}$-tocopherol 200 IU; resveratrol 20 ppm; resveratrol 200 ppm; methylated resveratrol 20 ppm; methylated resveratrol 200 ppm) with 4 replicates and 10 birds per replicate. Birds were reared for 35 days, and, at the age of 35 days, eight birds of average weight from each replicate were selected for blood samples collection. There were no significant differences on feed intake and feed conversion ratio. But final body weight and weight gain in antibiotics, resveratrol and methylated resveratrol treatments were significantly higher than no-antibiotics and ${\alpha}$-tocopherol treatments (P<0.05). There were no significant differences on carcass rate and relative organ weights among treatments, however, weights of liver and bursa of februcius in antibiotics, resveratrol and methylated resveratrol treatment were lower than other treatments. Weight of pancreas was high in resveratrol and methylated treatment. On the cecal microflora (total microbes, Coliform bacteria, Salmonella spp., and lactic acid bacteria), these in resveratrol and methylated resveratrol treatments didn't show the differences compared with those in no-antibiotics, antibiotics, and ${\alpha}$-tocopherol treatments. In the serum, there were no significant differences on creatinine, blood urea nitrogen (BUN), total protein, albumin, globulin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) among treatments, though globulin contents of reseveratrol 200 ppm and methylated resveratrol 20 ppm treatments decreased compared to those of other treatments. Immunoglobulin (IgA, IgG and IgM) were significantly decreased in antibiotics and resveratrol treatments compared to that of no-antibiotics and ${\alpha}$-tocopherol treatments (P<0.05). Superoxide dismutase (SOD) like activity tended to increase in resveratrol groups (P<0.05), however, there was no significant difference on malondiakdehyde (MDA) content among treatments. In conclusion, these results showed that resveratrol derived from mulberry can be used as alternative of antibiotics through improvement of broiler's performance and maintain of health.

Effects of Dietary Germanium on the Performance, Egg Quality and Blood Composition for the Finishing Stage of Laying Hens (산란말기에 게르마늄의 첨가 급여가 산란계의 생산성과 계란품질 및 혈액성상에 미치는 영향)

  • Lim, Chun Ik;Moon, Hong Kil;Kim, Sang Ho;Choe, Ho Sung;Ryu, Kyeong Seon
    • Korean Journal of Poultry Science
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    • v.45 no.2
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    • pp.119-124
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    • 2018
  • This study was conducted to assess the effect of dietary addition of Germanium (Ge) on performance, egg quality, serum biochemical properties and yolk fatty acid composition in laying hens. At 74 weeks of age, a total of 360 Hy-line brown commercial layers were divided into four treatments with five replicates per treatment. Four dietary levels of Ge (0, 1, 2 and 4%) were added to the basal diets (ME: 2,750 kcal/kg, CP: 16%) and fed corresponding diet for a period of 12 weeks. The effects of these treatments on production performance and egg quality were measured three times at four week intervals, and at the end of the experiment, blood and egg yolk fatty acid were analyzed. The results showed that production performance parameters including egg production rate, feed intake, egg weight, egg mass and feed conversion ratio were non-significant, but dietary addition of 2% Ge tended to increase egg production rate. Eggshell strength was found to be significantly higher in Ge supplemented groups than in the control group (P<0.05), and eggshell thickness was also trended to be improved in Ge treated groups. In serum, triglyceride content was significantly greater (P<0.05), and the highest total cholesterol was found in hens of the control group as compared with that of the Ge supplemented groups. The yolk fatty acid composition including polyunsaturated fatty acid, unsaturated fatty acid and saturated fatty acid were not affected among the treatments but addition of 2 or 4% Ge in basal diet had significantly (P<0.05) increased monounsaturated fatty acid. Therefore, supplementation of Ge in laying hens diet has positive effects on egg quality and triglyceride in serum.

A Study on Effects of the Transient Compression by Tightly Tied Necktie on Blood Flow in the Internal Jugular Veins Using 2D-PC MRA (2D-PC MRA를 이용한 넥타이의 순간적인 압박(壓迫)이 내경정맥의 혈류에 미치는 영향에 대한 연구(硏究))

  • Kim, Keung-Sik;Chung, Tae-Sub;Park, In-Kook;Lee, Bum-Soo;Kim, Hyun-Soo;Yoo, Beong-Gyu
    • Journal of radiological science and technology
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    • v.31 no.3
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    • pp.267-276
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    • 2008
  • The 25 healthy male volunteers aged from 20 to 50years old have been employed in this study. 2D-PC MRA was performed to measure the velocity of the blood flow in the internal carotid artery and internal jugular veins using 3.0T MRI Whole body (signa VH/i GE). ECTRICKS-CEMRA was performed to evaluate the pattern of blood circulation from internal carotid artery to internal jugular vein. Using 2D-PC MRA, the cross-section of the 4th and 5th cervical discs was scanned with 24cm FOV. Then the speed of blood flow was measured for internal carotid artery and internal jugular vein when the subject wears a necktie tightly and no tie. The average of maximum velocity of internal carotid arteries without a necktie was 72.13cm/sec in the right side and 74.96cm/sec in the left side(average 73.54cm/sec in both sides) while the average of maximum velocity of internal jugular veins without a necktie was -34.45cm/sec in the right side and -24.99cm/sec in the left side (-29.72cm/sec in both sides). However, when wearing a necktie tightly, the average of maximum velocity of internal carotid arteries was 61.35cm/sec in the right side and 65.19cm/sec in the left side(average 63.27cm/sec in both sides) while the average of maximum velocity of internal jugular veins was -22.14cm/sec in the right side and -17.93cm/sec in the left side(-20.03cm/sec in both sides). With the necktie tightly knotted, the average blood flow speed of both internal carotid arteries slightly decreased to 86% (63.27/73.54cm/sec) compared to no tie case in which both internal jugularveins significantly went down to 67% (-20.03/-29.72 cm/sec). Thus it is suggested that wearing a necktie affects the circulation of internal jugular veins(33% decrease in blood flow speed) more significantly than that of internal carotid artery(14% decrease in blood flow speed). Without a necktie, ECTRICKS-CEMRA showed natural blood circulation patterns of internal carotid arteries and internal jugular veins without any disturbances or compressions. However, when wearing a necktie tightly, ECTRICKS-CEMRA showed severe compression onto both internal jugular veins in all 25 volunteers. In conclusion, the result of the study showed that the tightly worn necktie instantly presses more internal jugular veins than internal carotid arteries, thereby significantly reducing the blood flow speed and leading to the temporary occlusion. Thus, the defecation or washing the face under the tightly tied necktie situations can cause the unexpected and temporary compression or occlusion of the internal jugular veins, subsequently leading to the occurrences of the stroke due to the secondary intracranial venous hypertension.

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Evaluation of Worker's Health and Occupational Exposure to Perchloroethylene in Laundries (Perchlotoethylene을 사용하는 세탁소 작업자들의 직업성 폭로와 건강에 관한 연구)

  • An, Sun-Hee;Lee, Jong-Hwoa;Park, Jong-An
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.4 no.2
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    • pp.224-239
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    • 1994
  • In this study we examined several subjective symptoms in an exposed group and an unexposed group to perchloroethylene. The exposed group consists to 30 workers employed in 23 dry-cleaning establishments located in Chung Cheung Do, whereas the unexposed group consists of 42 officers employed in a certain university. This study was conducted from October, 1993 to March, 1994. Also we investigated personal exposure levels and area concentration of PCE, and performed hematological and biochemical examination in blood and urine samples from the exposed group. The results are : 1. The exposed group highly complains several subjective symptoms, particularly in neuropsychiatry, eye, respiratory system and digestive system, compared with the unexposed group. But complaint rates in the exposed group are not related with PCE exposure levels. 2. PCE exposure levels for all dry-cleaning establishment varied widely, from 0.18 to 37.58ppm. The mean exposure level for centers of chain was 16.85ppm, and for local laundries was 8.83ppm, while for self-service establishment it was 3.07ppm. Eighty three percent of the workers were exposed less than the half-level(25.0ppm) of the Korea 50.0ppm standard for eight-hour PCE exposure. Seventeen percent of them exceeded the half-level of the Korea TLV. 3. Statistical correlation exists between the work load(number of operation cycles of equipment and the mass of processed textiles) and the personal exposure levels to be observed. 4. In hematological examination the values of WBC, RBC, Hgb, Hct, MCV, MCH, MCHC and PLT in the exposed group were within normal ranges. In biochemical examination(GOT, GPT, ALP, U-A and LDH) most of the items were within normal ranges. From this surveys conducted on 23 dry-cleaning establishments, the complaint rates of the exposed group to PCE in several subjective symptoms were higher than those of the unexposed group, and PCE exposure levels in all dry-cleaning establishment were below the Koera standard 50.0ppm. In hematological and biochemical examination the significant abnormalities by occupational exposure to PCE were not observed. However, the workers employed in dry-cleaning establishments are always faced with risk, becauses they are also exposed to several organic solvents used to remove stains. Therefore, various measures to improve occupational environment in dry-cleaning establishment should be considered.

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DNA damages with Fpg/Endo Ⅲ FLARE Assay in cynomolgus monkeys exposed to stainless steel welding fume (용접흄 흡입노출 영장류에서 Fpg/Endo Ⅲ FLARE Assay를 이용한 DNA 손상 및 회복)

  • Rim, Kyung Taek;Kim, Soo Jin;Chung, Yong Hyun;Kim, Hyeon Yeong;Maeng, Seung Hee;Yu, Il Je
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.17 no.4
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    • pp.272-281
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    • 2007
  • 선박제조업을 비롯한 운송업 및 건축업 등의 다양한 분야에서 용접기술이 이용되어 옴에 따라 용접근로자들에 대한 산업보건학적 관심이 높아지고 있다. 노출정도가 다양하기는 하지만 용접흄은 6가 크롬을 비롯한 금속화합물과 유해가스, 화학물질 등을 복합적으로 포함하고 있는 스테인레스 스틸 용접흄에 대한 유전독성영향을 평가하기 위하여 흡입챔버를 이용, 실험동물인 영장류에 스테인레스 스틸 용접흄을 노출시키고 혈액 내 lymphocytes에 생성된 용접흄 노출농도 및 시간별 DNA 손상정도 및 그 회복효소를 측정함으로써, 유해성이 완전하게 확인되지 않은 용접흄에 노출되어 나타날 수 있는 암을 비롯한 심각한 건강영향을 예방하기 위한 각 지표들을 찾아 그 유용성을 비교하고자 하였다. 영장류를 노출시키기 위해 robotic arm을 장치한 영장류 흡입노출 시스템을 개발하였으며, 이 노출 시스템을 이용하여 수컷 영장류 6마리에 대해 용접흄 노출시험을 실시하였는데 실험군은 대조군 2, 저농도 ($31mg/m^3$) 노출군 2, 고농도 ($63mg/m^3$) 노출군 2마리로 구성하였고, 1일 2시간씩 일주일에 5일 동안 용접흄에 노출시켰다. 노출 농도는 지속적으로 모니터링 하였고, 노출과정 중에 영장류의 혈액을 채취하여 lymphocytes를 분리, 단세포 DNA 손상을 선별하기 위해 DNA 손상회복 효소인 E. coli formamidopyrimidine-DNA glycosylase (Fpg)와 endonuclease Ⅲ (Thymine Glycol-DNA glycosylase) 투여와 Comet asaay (single cell gel electrophoresis, 단세포겔전기영동기법)를 결합시켜 이용하는 Fpg/Endo III FLARE 분석법을 사용하였다. Fpg enzyme에 의한 olive tail moment값의 변화는 16주 노출군부터 노출부검(34주)군 까지 노출농도가 높아짐에 따른 olive tail moment 기하평균 값의 양 반응관계를 보기는 어렵지만, 고농도군의 경우 27주 노출군에서 가장 높은 olive tail moment 값을 보이고 이후 차츰 감소하였다. 한편 16주에서 22주까지의 노출기간에서는 대조군에 비해 노출군에서 DNA손상정도(olive tail moment값)는 모두 유의하게 높았으나, 6, 12, 18, 25, 31, 33, 35주간 노출하였을 때는 다른 결과를 보였다. 각 실험군의 Fpg enzyme에 의한 tail length값의 분포를 살펴볼 때, 저농도군 및 고농도군에서 27주간 노출하였을 때 가장 높은 tail length 값을 보이고 이후 차츰 감소하는 경향을 보였다. 또한 16, 22주간 노출하였을 때 대조군에 비해 노출군에서 tail length 값이 유의하게 높았으나, 20주간에서만 양 반응관계가 관찰되었고, 다른 주간에서는 양 반응 및 기간 반응관계를 나타내지는 않았다. Endo III enzyme에 의한 olive tail moment값의 변화는 기간별 노출군에서 대조군에 비해 높은 DNA손상정도(olive tail moment값)를 나타내는 결과들이 있었지만, 10, 12, 16, 22, 25, 31주간 노출하였을 때 등 상당수 노출기간에서 반응관계를 나타내지는 않았다. 각 실험군의 Endo III enzyme에 의한 tail length값의 분포를 살펴볼 때, 18, 20, 27, 33주간 노출하였을 때 대조군에 비해 노출군에서 tail length 값이 조금 높았지만, 양 반응 및 기간 반응관계를 보이지 않았고 수치의 크기가 불규칙하게 변화하였다. 즉, DNA에 있어 산화된 pyrimidine을 형성하여 손상된 부위의 염기를 제거함으로써 AP site (abasic site)를 만들고 이들이 Comet assay를 통해 break로 전환된 것을 포함한 DNA손상을 측정하기 위하여 endonuclease III (Endo III)를 첨가시킨 Endo III FLARE 분석법을 실시한 결과, 본 연구에서 나타난 결과는 용접흄 노출 영장류에서 Olive tail moment 및 tail length 공히 노출량 및 노출기간 반응관계를 볼 수 없었다. Endo III FLARE 분석법을 통한 산화적 DNA 손상지표는 영장류에 적용하기에는 적응반응현상으로 대조군과 유의한 차이도 관찰할 수 없었고 더욱이 역으로 대조군에서의 자연발생적 수치가 더 높아질 수 있어 용접흄 노출 영장류의 모니터링 지표로 사용하기에는 제한점이 있었다.

A Study on their Health Promotion Behavior Influenced by Primary School Students' Self-concept (초등학생의 자아개념이 건강증진행위에 미치는 영향)

  • Lee, Deog-Weon;Park, Young-Soo
    • The Journal of Korean Society for School & Community Health Education
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    • v.1 no.2
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    • pp.29-48
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    • 2000
  • This study was designed to diagnose the correlations between health promotion behavior and primary school students' demographic characteristics and their self-concept, and also this study was aimed at representing the basic data of proper instruction method and school health program with the respective to primary school students' health promotion behavior through the above things. For this, author selected as 5th, 6th graders, 400 persons at 5 elementary schools located on Kyonggi province. This data utilized ANOVA, multiple regression analysis and correlation analysis by SPSS program. The findings of this study were as follows; First, there showed meaningful differences concerning their health promotion behavior according to students' demographic traits. There were a birth date, living standard, domestic environments etc. as a factors which influenced on their health promotion behavior. With this, from ex-past-facto verification for these variable factors, as their birth date was faster, living standard was higher, domestic environments was better, as their health promotion behavior was more promotive. Second, students' health promotion behavior marked 3.61 among total 5 paint with the respective to its fulfillment degree, their self-concept marked 3.45 among total 5 paint. Their mental health promotion behavior marked 3.71 with the respective to inferior category of health promotion behavior, which was the highest score. In the other hands, their physical health promotion behavior marked 3.71, social health promotion behavior marked 3.45. contrary the disease prevention, first-aid & safety, oral health, health & nutrition(P>.05). Third, there show meaningful difference, in the level of p-value <.001 with the respective to the correlations between primary school students' health promotion behavior and their self-concept, more their self-concept was positive, more their more their whole health promotion behavior(r=.479), the fulfillment degree of physical health promotion behavior(r=.384), mental health promotion behavior(r=.543), social health promotion behavior(r=.372) were high. Fourth, with the respective to the results of difference verification concerning their fulfillment degree of health promotion behavior according to the upper, middle, inferior group of self-concept, there showed statistically meaningful difference, in the level of p-value<.001. In the long run, more their self-concept was positive, more their whole health promotion behavior was high. With this, from the results of $Scheff\acute{e}$ verification, there showed meaning differences among the upper and middle group, upper and inferior group, middle and inferior group. Fifth, self-concept played the role as the most important prognostic factor with the respective to primary school students' health promotion behavior(23.0%), in the other hands, there showed positive weight of 24.0% concerning the fulfillment of whole health promotion behavior by domestic environments(1.0%). From the above results, primary school students' the fulfillment degree of health promotion behavior didn't reach to middle or inferior level. In the other hands, there showed positive effects in the correlations between self-concept and the fulfillment degree of health promotion behavior, and also high self-concept group was much positive considering inferior group in the fulfillment degree of health promotion behavior. Accordingly, more their self-concept was positive, more their fulfillment degree of health promotion behavior was effective. Eventually, in the future, there have to make an efforts to develope positive, substantial programs through their self-concept enhancement etc. in the adequate planning or operation for primary school students' health education and school health program.

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The actual conditions on drug abuse among High school students in Busan city (고등학생(高等學生)의 약물(藥物) 남용(濫用) 실태(實態))

  • Cho, Yeon-Sook
    • Journal of the Korean Society of School Health
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    • v.3 no.1
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    • pp.101-118
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    • 1990
  • This study was intended to investigate actual conditions and problems relating to a variety of substance which have been used by students. A Questionnaire survey was carried out with the subject of 2411 students in an academic boys' high school, academic girls' high school, technical boys' high school and technical girls' high school in Pusan, from the 15th day to 29th day of March, 1989. The summarized results were as follows. There was not a remarkable difference in distribution of these subjects in boys' & girls' high school. The common and good health condition of subjects accounted for 90 percent or higher. 24.4 percent of them also had smoking experience, 11.6 percent of which continues to smoking. The understanding rate of these substances name other than sedative, psychostimulants and antihypnotic accounted for 90 percent or higher. The experience rate taking these substances for one year showed that anodyne, digestive and nutritive tonic accounted for 70 percent, antihypnotic for 15.6 percent, sedative for 1.4 percent, respectively, and psychostimulants for 0.5 percent. Moreover. it was shown that drugs accounted for 1.5 percent, bond for 1.4 percent, and thinner for 0.5 percent. The rate of the daily experiencers who took anodyne, digestive, nutritive tonic, sedatives, and psychostimulants and so on was 7.7 percent, 6.2 percent, 5.2 percent, 5.9 percent, and 5.0 percent respectively. This fact implied that there was a serious problem in high school students' non - narcotic abuse. The usage rate of these substances for treatment purpose showed that anodyme accounted for 90 percent or higher, and digestive for 70-80 percent, respectively, where girl students showed higher rate than one of boy students. Additionally, there was higher the usage rate for other purposes. The usage rate of drugs was highest when these students felt melancholy and curiousity. Their obtaining place appeared that these students mainly obtained these drugs, bonds and thinners from a small shop or peddler and their friend while they usually obtained other substance from the pharmacy and medical institute. The first usage time of these substances appeared during the middle school (the age of 14-15) which was the highest rate. The smoker of all subjects used remarkly large substances as compared with one of no-smoker. Particularly, it appeared that the usage of drugs was very closely related to smoking. The large number of students did not use these substances for oesrable purposes even though they understood the name of these substances. For this reason, from primasy schools it is required to teach the students dependence and harmful effects caused by these substances abuse. Moreover, it was shown that these students firstly used these substances during the middle school (the age of 14-15)due to curiosity. As a result, it is very urgent to give the students health education suitabale for prevention of these substance abuse, when considering harmful effects of these substances. And so health education for no-smoking. Finally, considering that it is very easy to obtain these substances from a small shop and pharmacy, the regulation of these substances control should be considered and completed in the future.

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Long-term Changes in Soil Chemical Properties in Organic Arable Farming Systems in Korea (작물의 지속적인 유기 재배가 토양의 이화학적 특성변화에 미치는 영향)

  • Lee, Yun-Jeong;Choe, Du-Hoi;Kim, Seung-Hwan;Lee, Sang-Min;Lee, Yong-Hwan;Lee, Byung-Mo;Kim, Tae-Wan
    • Korean Journal of Soil Science and Fertilizer
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    • v.37 no.4
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    • pp.228-234
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    • 2004
  • In organic farming, nutrients for the crop production are mostly supplied by compost containing various organic materials. The long-term organic cultivation would result in continuous changes of soil chemical properties and fertility. The aim of this study was to investigate the contribution of long-term organic cultivation to the soil fertility in Korea focusing on the chemical properties of soil. Soil samples were collected from organic farms that had been cultivated for 8-10 years after certification of organic product through the conversion periods of 2-3 years. Thereby each organic farm had acquired optimal cultivating techniques and soil condition. We separated organic farms into three groups by cultivating crops, i.e. leaf vegetables, fruit vegetables and fruit trees. In each group, five representative farms were chosen in order to investigate the relationships between application rate of compost and nutrient contents in soil. The application rate of compost was approximately $10-15Mg\;10a^{-1}$ for the first 2-3 years at the beginning of organic farming and then reduced to a rate of $3-4Mg\;10a^{-1}$ after stabilization of organic matter content in soil with $30-50g\;10a^{-1}$. However, the continuous organic farming for 8-10 years resulted in accumulation of nutrients, especially of P, in soil probably due to the excessive amounts of compost applied. In conclusion, we suggest that the application rate and organic sources of compost should be decided on the basis of P content in soil by soil testing and thereafter the lack of soil N content for crop cultivation should be compensated by crop rotation with such as legumes. This might be an approach to the original meaning of organic farming as an environmental friendly agriculture.