• 한국농공학회논문집
• /
• 제52권6호
• /
• pp.19-26
• /
• 2010

Batch experiments were conducted to investigate growth and nutrient removal performance of microalgae Chlorella vulgaris by using piggery wastewater in different concentration of pollutants and the common growth models (logistic, Gompertz and Richards) were applied to compare microalgal growth parameters. Removal of nitrogen (N) and phosphorus (P) by Chlorella vulgaris showed correlation with biomass increase, implying nutrient uptake coupled with microalgae growth. The higher the levels of suspended solids (SS), COD and ammonia nitrogen were in the wastewater, the worse growth of Chlorella vulgaris was observed, showing the occurrence of growth inhibition in higher concentration of those pollutants. The growth parameters were estimated by non-linear regression of three growth curves for comparative analyses. Determination of growth parameters were more accurate with population as a variable than the logarithm of population in terms of R square. Richards model represented better fit comparing with logistic and Gompertz model. However, Richards model showed some complexity and sensitivity in calculation. In the cases tested, both logistic and Gompertz equation were proper to describe the growth of microalgae on piggery wastewater as well as easy to application.

• Journal of Preventive Medicine and Public Health
• /
• 제49권5호
• /
• pp.260-274
• /
• 2016

Objectives: Previous epidemiological studies about oxidative stress and depression are limited by hospital-based case-control design, single-time measurements of oxidative stress biomarkers, and the small number of study participants. Therefore, in this study, we analyzed the association between biomarker of oxidative stress and depressive symptom scores using repeatedly measured panel data from a community-dwelling elderly population. Methods: From 2008 to 2010, a total of 478 elderly participants residing in Seoul, Korea, were evaluated three times. Participants underwent the Korean version of the Short Form Generic Depression Scale (SGDS-K) test for screening depression, and urinary malondialdehyde (MDA) levels were measured as an oxidative stress biomarker. We used a generalized estimating equation with a compound symmetry covariance structure to estimate the effects of oxidative stress on depressive symptom scores. Results: A two-fold increase in urinary MDA concentration was significantly associated with a 33.88% (95% confidence interval [CI], 21.59% to 47.42%) increase in total SGDS-K scores. In subgroup analyses by gender, a two-fold increase in urinary MDA concentration was significantly associated with increased SGDS-K scores in both men and women (men: 30.88%; 95% CI, 10.24% to 55.37%; women: 34.77%; 95% CI, 20.09% to 51.25%). In bivariate analysis after an SGDS-K score ${\geq}8$ was defined as depression, the third and the fourth urinary MDA quartiles showed a significantly increased odds ratio(OR) of depression compared to the lowest urinary MDA quartile (third quartile OR, 6.51; 95% CI, 1.77 to 24.00; fourth quartile OR, 7.11; 95% CI, 1.99 to 25.42). Conclusions: Our study suggests a significant association between oxidative stress and depressive symptoms in the elderly population.

• 한국토양비료학회지
• /
• 제42권Spc호
• /
• pp.1-3
• /
• 2009

은나노입자는 살균 효과 때문에 농업현장에서 사용되고 있다. 그러나 은나노입자가 토질에 미치는 영향에 대해서는 아직 많은 정보가 없다. 그러므로 비료가 처리 되었을 때 특히 토양에 은나노입자를 처리한 효과에 대한 검증이 반드시 필요하다. 가리계 비료를 모의 실험하기 위해서 토양에 염화가리를 은나노입자와 함께 처리하였다. 은과 염소의 농도는 처리 후 78 내지 84% 그리고 kg 당 3.4 mg 정도 감소하는 경향을 보였다. 그리고 은나노입자와 염화가리를 혼합하였을 때 미생물의 숫자가 증가하였다. 이러한 결과로부터 비료시용은 토양에서 은나노입자의 살생물 효과에 영향을 미친다.

• 대한공간정보학회지
• /
• 제18권1호
• /
• pp.129-134
• /
• 2010

저탄소 녹색성장은 국내외적으로 중요한 정치적 이슈가 되고 있으며, 한국정부는 최근 저탄소 녹색성장을 위한 비젼을 발표하였다. 이런 관점에서 탄소배출 추정은 도시계획에 있어서 중요한 요소가 되고 있다. 탄소저감 계획을 수립하기 위하여 본 연구에서는 과거 40년 동안 진주시의 탄소배출 추정과 토지이용변화의 상호추이변화를 분석하였다. 토지적성평가 데이터베이스와 항공영상의 영상처리자료는 과거 40년간의 토지이용변화를 분석하는데 유효한 정보를 주었으며, 신주거지 개발에 의한 토지이용변화는 급격한 인구집중과 탄소배출증가를 가져왔다. 앞으로 저탄소 녹색성장을 위한 도시관리계획에 있어서 토지이용변화에 따른 탄소배출 증가를 계획수립 시 반드시 고려해야하며, 향 후 토지이용과 연료소비추정이 포함된 정확한 탄소배출 추정모델개발에 대한 추가적인 연구가 필요하다고 사료된다.

• 한국산학기술학회논문지
• /
• 제16권8호
• /
• pp.5067-5073
• /
• 2015

최근 물 순환의 급격한 변동을 수반하는 기후변화, 지속적인 인구증가, 인구집중화에 따른 문제들로 물관리에 관한 내용들이 연구되고 있다. 인구집중화가 된 곳에는 물관리 시스템에 관한 연구가 많이 이루어지고 있으나, 극지, 오지등 사람들의 왕래가 어려운 곳에서는 물관리가 힘든 실정이다. 특히 이러한 곳에서 수자원 관리를 하려면 전기가 필요하지만 이러한 곳에 전력공급 시스템 인프라를 구축하는데에는 많은 비용이 들기 때문에 오지에는 물관리가 어렵다. 따라서 본 연구에서는 이러한 오지에서 신재생에너지를 이용하여 전기를 공급하는 방안을 제안하고자 한다. 신재생에너지 중 최근 가장 이슈가 되고 있는 태양을 이용한 방식을 연구할 예정이며, 태양열을 이용하여 전기를 발전해 오지에서도 전기를 사용하여 물 관리 시스템을 사용할 수 있는 태양열 발전 시스템을 이용하여 ESS의 원료로 사용하는 시스템의 기초 구현 방안을 제시하였다.

• Journal of Ginseng Research
• /
• 제5권1호
• /
• pp.73-84
• /
• 1981

Effect of environmental factors and host on the growth and outbreak of various ginseng diseases was reviewed Environmental lectors included hydrogen ion concentration, moisture content, temperature, nutrition, and microbiol populations. Age of the ginseng plants in relation to several ginseng disease occurrence was also included in order to formulate the effective control measure for ginseng diseases. Damping-off caused by Rhizoctonia, Pythium, and Phytophthora, greymold by Botrytis, sclerotinia by Scleretinia, and phytophthora blight caused by Phytophthora were usually prevalent during the early growing season of ginseng when temperature is below 20$^{\circ}C$, while anthrac se caused by Colletotrichum, alternaria blight by Alternaria, and bacterial soft rot by Erwinia were so during the latter growing season when temperature is above 25$^{\circ}C$. However, the root rot incited by Fnarium and Cylindrocarpon caused severe damages throughout the growing season. Growth range of the temperature for a pathogen was highly related to the corresponding disease outbreak. Hydrogen ion concentration was highly related to the outbreak of sclerotinia, root rot, and red rot. Most severe outbreak of those diseases where the soil acidity was pH 4.7, pH 6.5- 7.5, and pH6.0-6.5, respectively. Nitrogen content in the soil was also related to outbreak of root rot and red rot. More red rot occurred where NH,-nitrogen is above 30 ppm and more root rot obtained when excessive nitrogen fertilizer applied. Yellow necrosis apparently was related to magnesium especially its ratio with potassium or calcium content in a soil. Fusarium Population showed significant .relations to missing rate of ginseng Plants in a Implanting ginseng field, while that of total bacteria showed similar relations in all ginseng field, However, in six year old ginseng fields, the more the Streptomyces population was, the less the Fusarium obtained. Consequently, less missing rate observed in a field where Streptomyces population was high. Damping-off, root rot, Rhytophthor a blight were mose severe on the nursery and on 2-3 years old ginseng plants, whereas sclerotinia, and grey cod, alteraria blight, anthracnose were severe on 4-6 years old ginseng plants. Root rot caused by Fusarium and Erwinia, however, was also severe regardless of the age of the plants when the roots were injured. Therefore, for the effective control of ginseng root rot most careful control of the disease during the early year should be rendered.

• 대한환경공학회지
• /
• 제28권7호
• /
• pp.764-769
• /
• 2006

미생물을 접종하지 않은 동전기 공정에서 전기분해에 의한 양극조에서 산소의 발생은 전류밀도에 비례하였으며 전해질을 순환시킴에 따라 생물반응기내 전해질과 함께 용존산소농도가 증가하였다. 전류의 공급과 함께 미생물 농도는 급격히 증가하였으며 이때 미생물의 산소소비량이 증가되어 용존산소농도가 감소되었다. Pentadecane-오염토양에 대한 동전기 생물학적 복원의 결과에서 높은 전류밀도 1.88 $mA/cm^2$에서 비록 산소의 발생량은 많았지만 오히려 증가된 유기산이 전해질 pH와 미생물 활성을 감소시키므로 미생물 농도와 제거효율이 0.63 $mA/cm^2$보다 낮게 나타났다. 0.63 $mA/cm^2$에서 적절한 산소의 공급과 동시에 전해액 pH의 감소가 작았으므로 최적의 미생물 농도와 제거효율을 얻을 수 있었다.

• Animal Bioscience
• /
• 제34권4호
• /
• pp.613-620
• /
• 2021

Objective: This study aimed at studying the potential use of Flemingia (Flemingia macrophylla) as a protein source fodder to improve nutrients digestibility and ruminal fermentation efficiency in beef cattle. Methods: Four, Thai native beef cattle were randomly assigned in a 4×4 Latin square design. Four levels of Flemingia hay meal (FHM) were used to replace soybean meal (SBM) in the concentrate mixtures in four dietary treatments replacing levels at 0%, 30%, 60%, and 100% of SBM. Results: The experimental findings revealed that replacements did not effect on intake of rice straw, concentrate and total dry matter (DM) intake (p>0.05). However, the apparent digestibilities of DM, organic matter, crude protein, acid detergent fiber, and neutral detergent fiber were linearly increased up to 100% replacement levels. Moreover, the production of total volatile fatty acids, and propionate concentration were enhanced (p<0.05) whereas the concentration of acetate was reduced in all replacement groups. Consequently, the CH4 production was significantly lower when increasing levels of FHM for SBM (p<0.05). Furthermore, rumen bacterial population was additionally increased (p<0.05) while protozoal population was clearly decreased (p<0.05) in all replacement groups up to 100%. In addition, microbial nitrogen supply and efficiency of microbial nitrogen synthesis were enhanced (p<0.05), as affected by FHM replacements. Conclusion: The findings under this experiment suggest that 100% FHM replacement in concentrate mixture enhanced rumen fermentation efficiency, nutrients digestibilities, bacterial population, microbial protein synthesis, and subsequently reduced CH4 production in beef cattle fed on rice straw.

• 보건행정학회지
• /
• 제3권2호
• /
• pp.81-99
• /
• 1993

The purpose of this research is to assess the geographical distribution of physicians and dentists and the degree of maldistribution of the physician. Data were obtained form the Korean Medical Association's report on physicians registry and census for 1990. To assess the degree of disparity in the rural-urban distribution of physician manpower and to identify changes in the distribution pattern, the Gini index of concentration was used. Major findings are as follows; 1. Urban-rural disparity in the distribution of physician manpower exists in all categories of manpower, i.e. physician, dentist, oriental medical doctor, general practitioner, medical specialist, practitioner, public health physician and public health dentist. Urban area which had 74.4% of nation's population, accounted for over 90% of all physician manpower. 2. In terms of the ration of physician manpower per 10, 000 population, in urban area, they were 8.2 physicians, 2.7 general practitioners, 5.5 specialists, 3.0 practitioners, 1.8 dentists and 1.3 oriental medical doctors. In rural area, the ratios were 1.4 physicians, 0.6 general practitioners, 0.9 specialists, 1.0 practitioners, 0.4 dentists and 0.4 oriental medical doctors. 3. Gini indicies computed to measure inequality of physician manpower distribution were 0. 3675 for physicians, 0.3372 for general practitioners, 0.3338 for specialists, 0.2263 for practitioners, 0.3132 for dentists and 0.3293 for oriental medical doctors. 4. Inspite of increase in the number of physician manpower, urban concentration of physician manpower intensified from 1980 to 1990. However, the Gini index for all physician manpower fell by 18.3~36.7% from 1980 to 1990, indicating more even distribution. 5. In rural area, the public health physicians and dentists had increased the ratios of physicians, general practitioners, practitioners and dentists per 10, 000 population remarkebly, and had decreased the Gini indicies of physicians, general practitioners, practitioners and dentists. Thus, public health physicians and dentists contributed to improve the distribution of physician manpower in rural area. Based on the results of this study, long-term and rational manpower policies should be developed to solve the problem of geographical maldistribution of physician manpower as well as short-term policy for inducing physicians to the rural areas.

• Journal of Ginseng Research
• /
• 제48권2호
• /
• pp.229-235
• /
• 2024

Background: Plant health is directly related to the change in native microbial diversity and changes in soil health have been implicated as one of the main cause of root rot. However, scarce information is present regarding allelopathic relationship of Panax notoginseng root exudates and pathogenic fungi Fusarium oxysporum in a continuous cropping system. Methods: We analyzed P. notoginseng root exudate in the planting soil for three successive years to determine phenolic acid concentration using GC-MS and HPLC followed by effect on the microbial community assembly. Antioxidant enzymes were checked in the roots to confirm possible resistance in P. notoginseng. Results: Total 29 allelochemicals in the planting soil extract was found with highest concentration (10.54 %) of p-hydroxybenzoic acid. The HPLC showing a year-by-year decrease in p-hydroxybenzoic acid content in soil of different planting years, and an increase in population of F. oxysporum. Moreover, community analysis displayed negative correlation with 2.22 mmol. L^-1 of p-hydroxybenzoic acid correspond to an 18.1 % population of F. oxysporum. Furthermore, in vitro plate assay indicates that medium dose of p-hydroxybenzoic acid (2.5-5 mmol. L^-1) can stimulate the growth of F. oxysporum colonies and the production of macroconidia, as well as cell wall-degrading enzymes. We found that 2-3 mmol. L^-1 of p-hydroxybenzoic acid significantly increased the population of F. oxysporum. Conclusion: In conclusion, our study suggested that p-hydroxybenzoic acid have negative effect on the root system and modified the rhizosphere microbiome so that the host plant became more susceptible to root rot disease.