• Journal of the East Asian Society of Dietary Life
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• v.15 no.6
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• pp.687-699
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• 2005

In order to investigate the effect of dietary zinc and phytic acid levels on protein metabolism in rats, male rats of Sprague-Dawley strains weighing approximately $60\~74g$ were fed different diets which contained 0, 0.35 and $1.05\%$ phytic acid each at 3 levels of zinc(0, 30 and 1,500 ppm zinc) for 28 days. Result obtained in this experiment are summarized as follows; 1. Body weight gait food consumption food efficiency ratio and protein efficiency ratio were lower in the rats fed zinc deficient diet(0 ppm zinc) than in those consuming 30 or 1,500 ppm dietary zinc, and the additional effect of phytic acid were not observed in all of then 2. Liver weight was lower in the rats fed 30 ppm zinc diet than in those fed 0 or 1,500 ppm-zinc diet but kidney and spleen weights were lower in the rats fed zinc deficient diet than in those fed 30 or 1,500 ppm-zinc diet Among organs measured only the liver appeared to be influenced by dietary phytic acid: the more the dietary phytic acid, the more the weight of liver, 3. Fecal nitrogen was decreased in the rats fed zinc deficient diet compared with those fed 30 or 1,500 ppm dietary zinc. Urinary nitrogen was increased in the rats fed $1.05\%$ dietary phytic acid compared with those fed 0.35 or $0\%$ dietary phytic acid Nitrogen retention of rat was influenced by neither dietary zinc nor phytic acid. 4. Urea nitrogen was decreased with increasing dietary zinc levels, and creatinine and uric acid levels were increased with increasing dietary zinc concentration or with additional quantity of phytic acid. Uric acid appeared to be influenced by zinc x phytic acid interaction; especially, the presence of phytic acid in the 30 ppm-zinc diet had significant effect on uric acid content. 5. Hemoglobin concentrations and hematocrit ratio were higher in the rats fed 30 ppm dietary zinc than in those fed 0 or 1,500 ppm-zinc diet Serum zinc concentration was increased with increasing dietary zinc levels. The content of total protein albumin and BUN and the ratio of albumin to globulin in serum, and protein content in liver were influenced by neither dietary zinc nor phytic acid.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.505-512
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• 2006

In Korea, silicate fertilization (SF) is being practiced every four years to enhance rice production. However, the relationship between nitrogen (N) and SF in view of growth characteristics and grain yield of rice has not been examined after watermelon cropping in plastic film house. This study was carried out to identify useful critical N and Si fertilizer levels to sustain grain yield and to improve N use efficiency for rice. The watermelon-rice cropping system has maintained for three seasons in each year from 1998 to 2001 by farmer before this experiment. Experiments on N and Si fertilization levels were evaluated with Hwayoungbyeo (Oryza sativa L.) in 2002 and 2003 at Uiryeong, Korea. The goal of this experiment was to find out the optimum N and Si levels to sustain rice yield by reducing excessive N fertilizer in watermelon-rice cropping system. Nitrogen fertilization (NF) levels were three ($0,\;57,\;114kg\;ha^{-1};0,\;50,\;100%$ of conventional NF amount) and five (0, 25, 50, 75, 100%) in 2002 and 2003, respectively, and combined with three SF levels ($70,\;130,\;180mg\;kg^{-1};100,\;150,\;200%$ which were adjusted with Si fertilizer in soil) were evaluated for the improvement of N and Si fertilization level in both years. Rice yielded 3.98-5.95 and 2.84-4.02 t/ha in 2002 and 2003, respectively. Our results showed the combinations of 50% and 100% of N with 200% level of Si produced the highest grain yield in both years, respectably. The grain yield was greatly improved in plot of N25% level when compared to conventional NF (Nl00%) in 2003. In conclusion, NF amount could be reduced about 50% compared to recommended level by specific fertilization of N and Si combination levels for rice growing and grain yield after cultivation watermelon in paddy field.

• The Korean Journal of Mycology
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• v.10 no.4
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• pp.193-202
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• 1982

The changes of total carbohydrates and trehalose levels during differentiation of A. niger were studied. Aspergillus niger was cultivated in Czapeck-Dox medium by the method of surface culture and shake culture. Total carbohydrates and trehalose were fractionated and determined by the method of Trevelyan and Harrison (1956). Total carbohydrates and trehalose accumulated in A. niger during sporulation. The influences of nutritional starvation on the levels of cellular carbohydrates in A. niger, which was cultivated in each nitrogen, phosphate and glucose limited Czapeck-Dox medium, were studied. The levels of total carbohydrates and trehalose in A. niger cultivated in nitrogen limited medium increased much than those cultured in full medium. The total carborates and trehalose levels in A. niger cultivated in phosphate limited medium increased, but the increases were less than those cultured in nitrogen limitted medium. In glucose limited medium, any changes of total carbohydrates and trehalose levels were not found. It is considered that the biochemical mechanisms responsible for the changes of total carbohydrates and trehalose levels may be related with differentiation of Aspergillus niger.

• Journal of Nutrition and Health
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• v.28 no.4
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• pp.259-267
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• 1995

A study was conducted to investigate nitrogen balance and to estimate daily nitrogen requirement in 43 Korean female college students students maintaining their usual diet and activity levels. Nitrogen intake and excretion were measured in two separate peroids about one month apart, each period lasting for 3 days. Nitrogen intake was assessed by duplicate portion analysis of diet, and N excretion in faces and urine were measured during the study period. Mean daily nitrogen intake level was 129.3mg/kg B.W and the apparent digestibility of nitrogen was 76%. Mean daily urinary nitrogen excretion was 113.5mg/kg BW. 895 of total nitrogen intake. Mean daily nitrogen balance of subjects was -14.5mg/kg BW. Mean daily requirements of nitrogen for 0 balance, calculated by regression analysis of N balance and energy-adjusted N intake. were 1) 197.mg/kg B.W with the present energy intake level of the study subjects. 2) 157mg/kg B.W when energy intake is sufficient to maintain energy balance, and 30 130mg/kg B.W. when energy intake is Korean RDA level for moderate activity. When energy intake level is sufficient to meet their requirement, daily protein requirement for 0 balance is about 1.0g/kg B.W. The results of this study indicate that nitrogen intake level of young female college students is not sufficient to meet their requirements, and they should increase protein intake together with increase in energy intake.

• Journal of Nutrition and Health
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• v.24 no.1
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• pp.20-29
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• 1991

This study was carried out to compare the protein quality of lamb and beef meat. by feeding to growing rats. Sixty weanling rats, 30 males and 30 females, were blocked into 12 groups(6 gruops of males and 6 groups of females). They were fed casein. beef, or lamb as a protein source at two levels, 6 and 15%, for 5 weeks. The amount of food intake. food efficiency ratio, protein efficiency ratio. body weight gain. and the weights of skeletal muscles and liver were measured. Nitrogen retention, protein content in the liver and skeletal muscles, and the levels of protein and cholesterol in the serum were also assayed. Summarzing the results, there were no significant differences between lamb and beef on the growth and nitrogen utilization in the rats fed same percentage of protein diet. However. rats fed 15% protein diet showed significantly higher growth rate than those fed 6%. Therefore, it can be concluded that lamb is as good a protein food as beef in terms of protein quality.

• Korean journal of applied entomology
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• v.47 no.3
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• pp.237-248
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• 2008

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with nitrogen contents of 5 mM, 10 mM, 30 mM, and 60 mM. As the nitrogen level in hydroponics increased, it also increased in the plant whereas that of K, Ca, and Mg decreased. More nitrogen in hydroponics resulted in increased contents of water and crude protein, and decreased ash, carbohydrates, and fibers within the plant. Biomass was the heaviest as 989.5 g at 10 mM and the lightest at 60 mM. Leaf thickness and the content of chlorophyll increased as the content of nitrogen increased. Laboratory leaf disc tests obtained from plants grown at various nitrogen levels revealed that feeding and oviposition preferences of T. urticae were high at 30 mM and low at 5 mM. Ratio of damaged leaf by naturally occurring T. urticae on eggplants of 99 days post-transplant in the greenhouse was the highest as 98% at 60 mM. Degrees of damage on eggplants with and without T. urticae infestation turned up more as the differences in the levels of nitrogen in the hydroponics get bigger. No definite differences in the rate of T. urticae development was found between nitrogen treatment levels but, mortalities in immature stages dropped as the nitrogen levels went up. Adult longevity was the longest of 11.9 for female and 6.9 days for male at 60 mM. Oviposition period was also the longest as 11.7 days at 60 mM and shortened as the level of nitrogen decreased. The number of eggs oviposited was the most as 144.4 at 60 mM while it was the least as 41.0 at 5 mM. Sex ratio was 0.75 in favor of female at 10 mM. $R_o$ and T increased, no trends were detected in $r_m\;and\;{\lambda}$, while Dt decreased as the levels of nitrogen went up.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.44-50
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• 1981

This experiments was carried out to evaluate the effect of nitrogen retention on different levels of crude protein intake according to live weight, and the crude protein and urea content in serum of the Korean native goat. The results obtained are as follows: 1. When the female goat at 8 months age (14kg) had taken nitrogen free diet, the content of endogenous urinary nitrogen was 1.29g and endogenous fecal nitrogen was 1.27g per day. Therefore, the goat needs minimum level of crude protein per day. 2. When the thermometer checked below-$10^{\circ}C$, the nitrogen retention rate showed minus reaction in spite of 20% crude protein level. This suggested that the low temperature was consumed higher energy to maintain the body. 3. The nitrogen retention rate of the pregnant female goat of 20kg live weight, however, decreased as compared with the growing goat and was 17~20%. 4. According to the levels of crude protein were lower, crude protein and urinary nitrogen contents in serum were greatly decreased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.5
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• pp.288-293
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• 2000

Two rice cultivars (Oryza sativa L.), Hwa-seongbyeo of Japonica type and Taebackbyeo of Indica/Japonica type, were cultivated with hydroponic culture to examine nitrogen effects on the growth responses, contents and utilizations of carbohydrates, and the ripening velocity of grains with three different N levels. Plant height and tiller number were clearly increased to 80 ppm N level compared to 40 ppm N level and then they were slightly decreased in N level of 120 ppm. Higher dry weights were appeared with 80 ppm N level than did with other N levels, showing statistically differences in both cultivars and N levels, while dry weight of roots was heavier with decreasing the N levels. Therefore, T/R ratios were not significantly different among N levels, although there was statistically differences between rice cultivars. After the flowering stage, higher water-soluble carbohydrate (WSC) and water-insoluble carbohydrate (WISC) were contained in stem compared with other parts, showing that WISC of sheath and stem, unlike WSC, was significantly different among N levels. Starch of grain, WISC, was remarkedly increased from 3.0% at just after the flowering to 52.0% and 75.0% at 15 and 30 day after the flowering, respectively, showing that lower N application had faster accumulation of starch in rice grains. N would affect the contents of carbohydrates of each tissue, and starch accumulation in rice grains.

• The Korean Journal of Ecology
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• v.26 no.2
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• pp.71-74
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• 2003

Effects of nitrogen addition on the growth of Indigofera pseudo-tinctoria (Leguminosae) in the waste landfill site was investigated. Nitrogen fertilization in the nitrogen poor soils of waste landfill may influence the growth of nitrogen fixing plants beneficially or detrimentally. When I. pseudo-tinctoria was fertilized with three different levels of nitrogen, the coverage of plants treated with 46 g N/$m^2$ and 460 g N/$m^2$ was significantly less than that of plants treated with 23 g N/$m^2$. The growth rates of plant height treated with 46 g N/$m^2$ and 460 g N/$m^2$ were significantly less than those of plants treated with 23 g N/$m^2$. The growth rates of plant diameter treated with 46 g N/$m^2$ and 460 g N/$m^2$ were significantly less than those of plants treated with 23 g N/$m^2$. Dry weights of whole plants in control sites were higher than those of all the others nitrogen treatment sites. Nodule numbers were higher in control plants than those of plants in all the other nitrogen treatment sites. It is suggested that nitrogen fertilizer addition over 23 g N/$m^2$ affect the growth of some nitrogen fixing plants, such as I. pseudo-tinctoria, negatively.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.134-141
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• 2000

The person' spending time in underground s[aces within indoor environment show a tendency to increase every year, but in Korea, levels and sources of pollutant in underground spaces have not been well-characterized. Therefore, as part or a larger indoor environmental study, conducted at subway station in Seoul, nitrogen dioxide was measured using passive samplers in 16 subway stations, 2 tunnels and 70 workers of subway station. The mean concentrations of nitrogen dioxide in subway stations were $27.87{\pm}7.15$ ppb at station office, $35.76{\pm}8.35$ ppb at platform, $52.60{\pm}13.04$ ppb at outdoor, respectively, and the Indoor/Outdoor ratio were 0.49~0.93. The mean concentrations of nitrogen dioxide in tunnels were $44.91{\pm}4.67$ ppb in Chunggye-Nowon tunnel with a single track, $42.55{\pm}3.33$ ppb in Mokkol-Taenung tunnel with double track, respectively, and as a result of t-test, a single track levels were higher than double track levels(p<0.05). The mean personal exposure of the subject of station workers was $29.40{\pm}9.75$ ppb.