• Korean Journal of Soil Science and Fertilizer
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• v.11 no.3
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• pp.127-144
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• 1979

Recent trend in the studies on the forming processes, chemical characteristics and chemical structure of humic substances with some discussions are reviewed and some arguments for the elucidation of the chemical structure of humic substances are summarized.

• Neonatal Medicine
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• v.16 no.2
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• pp.221-233
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• 2009

Purpose: Erythropoietin (EPO) has neuroprotective effects in many animal models of brain injury, including hypoxic-ischemic (HI) encephalopathy, trauma, and excitotoxicity. Current studies have demonstrated the neuroprotective effects of EPO, but limited data are available for the neonatal periods. Here in we investigated whether recombinant human EPO (rHuEPO) can protect the developing rat brain from HI injury via modulation of NMDA receptors. Methods: In an in vitro model, embryonic cortical neuronal cell cultures from Sprague-Dawley (SD) rats at 19-days gestation were established. The cultured cells were divided into five groups: normoxia (N), hypoxia (H), and 1, 10, and 100 IU/mL rHuEPO-treated (H+E1, H+ E10, and H+E100) groups. To estimate cell viability and growth, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was done. In an in vivo model, left carotid artery ligation was performed on 7-day-old SD rat pups. The animals were divided into six groups; normoxia control (NC), normoxia Sham-operated (NS), hypoxia-ischemia only (H), hypoxia-ischemia+vehicle (HV), hypoxia-ischemia+rHuEPO before a HI injury (HE-B), and hypoxia-ischemia+rHuEPO after a HI injury (HE-A). The morphologic changes following brain injuries were noted using hematoxylin and eosin (H/E) staining. Real-time PCR using primers of subunits of NMDA receptors (NR1, NR2A, NR2B, NR2C and NR2D) mRNA were performed. Results: Cell viability in the H group was decreased to less than 60% of that in the N group. In the H+E1 and H+E10 groups, cell viability was increased to >80% of the N group, but cell viability in the H+E100 group did not recover. The percentage of the left hemisphere area compared the to the right hemisphere area were 98.9% in the NC group, 99.1% in the NS group, 57.1% in the H group, 57.0% in the HV group, 87.6% in the HE-B group, and 91.6% in the HE-A group. Real-time PCR analysis of the expressions of subunits of NMDA receptors mRNAs in the in vitro and in vivo neonatal HI brain injuries generally revealed that the expression in the H group was decreased compared to the N group and the expressions in the rHuEPO-treated groups was increased compared to the H group. Conclusion: rHuEPO has neuroprotective property in perinatal HI brain injury via modulation of N-methyl-D-aspartate receptors.

• Neonatal Medicine
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• v.16 no.2
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• pp.163-171
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• 2009

Purpose: This study was conducted to determine the incidence, causative pathogens, risk factors and mortality for early onset sepsis in the first three days in very low birth weight infants. Methods: The medical records of 1,124 very low birth weight infants admitted to the neonatal intensive care unit of Samsung Medical Center between November 1994 and December 2008 were retrospectively reviewed. The incidence, causative pathogens, risk factors, and mortality for early onset sepsis in the first 3 days of life in very low birth weight infants were evaluated. Results: Early onset sepsis, as confirmed by positive blood cultures, was present in 17 of 1,124 infants (1.5%). Sixty-four percent of the isolated pathogens were gram-positive bacteria and 35% of the isolated pathogens were gram-negative bacteria. The dominant pathogens of early onset sepsis included Staphylococcus aureus (23.5%), Esherichia coli (23.5%), and Enterococcus (17.6%). Vaginal delivery (adjusted odds ratio [OR], 3.7; 95% confidence interval [CI], 1.3-10.3; P=0.01) was associated with early onset sepsis. The overall mortality (adjusted hazard ratio, 3.0; 95% CI, 1.4-6.5; adjusted P=0.0039) and mortality within 72 hours of life (adjusted hazard ratio, 6.5; 95% CI, 2.2-18.9; adjusted P=0.0005) of infants with early onset sepsis were higher than that of uninfected infants. Conclusion: Early onset sepsis remains an uncommon, but potentially lethal problem among very low birth weight infants. Knowledge of the likely causative organisms and risk factors for early onset sepsis can aid in instituting prompt and appropriate therapy, in order to minimize mortality.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.599-605
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• 1996

A total of 249 patients undergoing isolated coronary revascularization were studied for the occurrence of postoperative atrial fibrillation(AF). Possible associations of this arrhythmia with various preoperative, intraoperative and postoperative factors were studied by univariate and multivariate analysis. The overall incidence of postoperative AF was 15%, with the median time occurence of 48 hours(mean time : 59.1 $\pm$ 56.9 hours) after arrival to the intensive care unit. Cardiac index decreased significantly after occurence of AF(p=0.001). There were no in-hospital complications in those patients with AF. Univariate studies indicated preoperative ejection fract on(EF), triglyceride level, postoperative peak CKMB isoenzpme and atrial pacing to be the dominant factor promoting postoperative AF, with an increasing prevalence in lower EF(p=0.025), triglyceride(p=0.006) and peak CKMB isoenzyme(p=0.002), and in patients with atrial pacing(p=0.001). Hospital stay(p=0.001) and late mortality(p=0.003) were significantly increased in patients with postoperative AF Multivariate analysis showed that body weight and postoperative atrial pacing to be the dominant factor promoting postoperative AF, with an increasing prevalence in over- weight patients(p=0.011) and patients with atrial pacing(p=0.001). Both univariate and multivariate analy- sis showed that the age was not a significant factor but tended to promote postoperative AF respectively (p=0.053, 0.064). After 30.1 $\pm$ 11.4 months gfollow-up, those patients with AF had sinus rhythm. We think that we must try to prevent postoperative AF after ccoronary artery bypass grafting because of its deleterio s hemodynamic effect, prolonged hospital stay, and increased late mortality.

• Journal of Animal Science and Technology
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• v.48 no.2
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• pp.293-306
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• 2006

We characterized physicochemical properties and examined the organoleptic and textural evaluations of Feta cheese made from goat's milk. Nutritional compositions of goat Feta cheese were fat 23.50%, protein 11.03% with moisture content of 59.54%. Cell numbers of lactic starter cultures in Feta cheese maintained from log 8.46 CFU/g and pH 5.76 during storage at 4℃ for 14 day's aging. The color of Feta cheese was whitish (L. 93.19) at after finishing brine salting, but became a little yellowish(b. 3.52) (a. -0.71). For texture profile analysis of goat Feta cheese, hardness, fracturability springness, and cohesiveness seemed to be week, but adhesiveness gumminess, chewiness, and resilience were enhanced as aging times extended to 14days, resulted in the overall textural properties was to be superior to control cheese(commercial Mozzarella cheese). Organoleptic evaluations were examined based on the intensities and the preferences for flavour, tastes, texture and mouth feeling. saltiness, bitterness and acidity were stronger in the intensities than control cheese, but the preferences were enhanced by aging to be better than control cheese at 14 days and later on, however, the texture changed to be weaker in hardness and unpleasant in mouthfeel. The fatty acid compositions of Feta cheese analysed by Gas chromatography were saturated fatty acid 42.06%, monoenoic acids 29.67%, di-enoic acids 24.24%, tri-enoic acids 1.21%.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.106-111
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• 1998

This study has been focused on both estrogenic and proliferating activity of genistein (GEN) and bisphenol A (BPA). GEN and BPA enhance the proliferation of estrogen-dependent MCF-7 human breast cancer cells at concentrations as low as 100 nM of GEN and 8 ng/ml of BP A achieving similar effect to that of estradiol at 1 nM. Expression of the estrogen responsive gene, pS2 was also induced in MCF-7 cells by treatment with genistein at dose as low as 1 nM and BPA at dose as low as 4 ng/ml. Using 21 day-old ovariectomized nude mice, we examined end-bud formation and mammary gland development after treatment with bisphenol A or genistein. Compared with untreated control, mammary gland development and end-bud formation were significantly increased in mice fed genistein or bisphenol A (p<0.05). Taken together, it is concluded that GEN and BP A can act as an estrogen agonist resulting in cell proliferation and induction of the estrogen responsive pS2 gene in MCF-7 cells in vitro and in athymic mice in vivo, respectively. Therefore, it is suggested that GEN and BP A might modulate human endocrine system and these compounds might be considered as a endocrine modulator at the low levels of doses.

• Journal of fish pathology
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• v.3 no.1
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• pp.21-25
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• 1990

In inland aquaculture, a lot of fishes often died cause of touch of L. carteri which is attached on the net cage. In this works, the experiment were carried out on classification of species, toxin test, and extermination with some chemicals. A bryozoa from net cage in lake Okjeong is classified into the Phylactolaemata, Lophopodella carteri Hyatt. A bryozoa broke out firstly on the 30th of June with water temperature up to $31^{\circ}C$ and it reattached on the net with water temperature below $30^{\circ}C$. Size of bryozoa colony is about $0.8{\times}0.6{\sim}1.7{\times}1.5cm$. Water column of attachment was 0~5m and the peak is 2~3m. In toxin test on the israeli carp, goldfish and catfish touched with bryozoa for 1 minute at $25^{\circ}C$ of water temperature, a dead fish appeared at 20 minutes after touched. Mortality was 90% for israeli carp and 100% for goldfish at 100 minuties after touched, but catfish was not died at all. It was supposed that the toxin is from nematocyst being around tentacles and this toxin act a deadly poison on a israeli carp and goldfish. In extermination test, the bryozoa treated with 300ppm of formalin, 5% of sodium chloride, 5ppm of malachite green, 200ppm of potassium permanganate, 1000ppm of potassium iodide, 10ppm of DDVP for minute respectively, all of them were not effected.

• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.216-227
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• 2008

To understand eutrophication in the upper regions of brackish Lake Sihwa with a limited water exchange, temporal and spatial distributions of pollutants in water and sediment were investigated from March to October in 2005 and 2006. Also, pollution levels of water and sediment were estimated by trophic state index (TSI) and sediment quality guideline (SQG). Total nitrogen (TN), total phosphorus (TP), organic matter (COD), and chlorophyll $\alpha$ (Chl-$\alpha$) concentrations in the surface waters were largely varied temporally and spatially, and the variations were highest in the middle areas where strong halocline was formed. Chl-$\alpha$ concentrations in the middle area were very high in April (>$900\;{\mu}g\;L^{-1}$) when algal blooms (red tides) occurred. The relationships between TN and Chl-$\alpha$ (r=0.31), and TP and Chl-$\alpha$ (r=0.65) indicated that the algal growth was primarily affected by phosphorus rather than nitrogen. The distribution of COD was similar to that of Chl-$\alpha$, indicating that the autochthonous organic matters may be a more important carbon source, especially in the middle areas. The brackish water regions were classified as eutrophic or hypertrophic based on their TSI values ($69{\sim}76$). In addition, the content of nutrients (especially TP) in surface sediments were classified as severe polluted state, except the upper areas. Major causes of the eutrophication observed were probably due to high nutrients loading from watersheds, the phosphorus release from anaerobic sediment, and long retention time by the limited water exchange through the sluice gates.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.4
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• pp.239-244
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• 2005

This study was conducted to investigate the effect of the planting densities and nitrogen levels on the growth characteristics, dry matter yield and nutritive value of corn for silage in alpine area(altitude 800m a.s.1.) of National Livestock Research Institute from 2001 to 2002. The experiment was arranged in a split plot design with three replications. Main plots consisted of three planting densities, low(67,000 plants/ha), medium(89,000 plants/ha) and high(95,000 plants/ha). Sub plots consisted of three nitrogen levels, 150 kg/ha, 200 kg/ha, and 250 kg/ha. Tassel height of corn was increased with decreasing planting density, and nitrogen level of 200 kg/ha in all main plots. Ear height of corn was decreased with increasing planting density, and 150 kg/ha of three nitrogen levels. But there were no significant differences among treatment in tassel and ear height. Although dry matter ear ratio of whole com was increased with decreasing planting density, there were no significant differences among treatments. But there were significant differences among nitrogen levels(P<0.05). Dry matter yield of com was high with increasing planting density, but there were no significant differences among treatments. And DM yield of corn was significant difference among nitrogen levels(P<0.05). Crude protein content of corn was the highest with high planting density and low nitrogen level. NDF and ADF content of com was the highest with low planting density and nitrogen levels of 200 kg/ha in all main treatments. These results indicate that low planting density(67.000 plants/ha) and nitrogen of 150-200 kg/ha would be the optimum level fur dry matter yield and nutritive value of silage com in alpine area.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.85-91
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• 1988

A field experiment was conducted to determine the effects of shading degrees (0: full sunlight, 25, 50 and 75%) on the proximate components, cell wall constituents (CWC), digestibility, water soluble carbohydrates (WSC) and nitrate nitrogen ($NO_3$-N) concentration of grasses grown in forest. For the test different artificial shading houses were established and pasture species used were orchardgrass, timothy, perennial ryegrass and ladino clover. The experiment was performed at LES in Suwon. 1985. 1. Considering proximate components, CWC and digestibility of grasses, ladino clover showed the best quality, and then perennial ryegrass. 2. The contents of crude protein, crude ash, and digestibility of grasses were increased with shading, regardless of pasture species. As the shading degrees are increased, the contents of crude fiber in orchardgrass, perennial ryegrass and timothy were decreased, while that in ladino clover was increased with shading. 3. Grasses grown in spring showed higher digestibility than those grown in summer season. 4. The content of WSC was the highest in perennial ryegrass, and then ladino clover, orchardgrass, and timothy, in that order. Also WSC was decreased as the shading degrees are increased. 5.The content of $NO_3$-N was the highest in perennial ryegrass, and then orchardgrass, ladino clover and timothy, in that order. Also the $NO_3$-N was significantly increased with higher shading level. In the regression equation between shading degrees and $NO_3$-N ($r^2$=0.90**, TEX>$r^2$=0.95**), shading degree of 43 to 44% was critical level, causing nitrate poisoning to animal. 6 Considering grass quality, dry matter yield and $NO_3$-N, less than 40% of shading degree (over 60% of full sunlight) was desirable for better grassland improvement, management and utilization in the forest.