• Biomedical Science Letters
• /
• v.16 no.4
• /
• pp.349-357
• /
• 2010

We have examined the histological changes of skin during hair follicle growth after depilation in C57BL/6N mice. We first studied on histological changes of number of mast cells and thickness of skin during hair follicle growth periods (telogen, 1 day, 3 day, 5 day, 10 day, 14 day, 17 day and 21 day after depilation) by toluidine blue, Giemsa and H&E staining methods. We second studied immunoreactive density of cytokines and Brdu labeled cells in skin during hair follicle growth periods after depilation in C57BL/6N mice by immunohistochemical methods. The histological changes on skin thickness was increased from telogen to 14 day. The number of mast cells was decreased in 3,5 and 10 day and increased in 14, 17 and 20 day after depilation. Immunoreactive density of cytokines [protein kinase C-${\alpha}$ (PKC-${\alpha}$), c-kit, and vascular endothelial growth factor (VEGF)] in 1, 3, 5, 10, and 14 day after depilation was mildly stained in bulge and cutaneous trunci m., but immunoreactive density of cytokines in 17 and 21 day was heavily stained in epidermis, bulge, outer root sheath (ORS), inner root sheath (IRS) and cutaneous trunci m.. Immunoreactive density of Brdu labeled cells in skin in 1 and 3 day was heavily stained in bulge, epidermis and connective tissue under the cutaneous trunci m.. In all periods, immunoreactive density of Brdu labeled cells in skin was heavily stained in bulge, subcutaneous tissue, cutaneous trunci m, ORS and IRS. These experiments suggest that histological changes related to hair follicle growth elevated mast cell counts, skin thickness and epidermis thickness and heavily stained immunoreactive density of cytokines and Brdu labeled cutaneous trunci m. and connective tissue under the cutaneous trunci m. after depilation in C57BL/6N mice.

• Fisheries and Aquatic Sciences
• /
• v.18 no.1
• /
• pp.57-63
• /
• 2015

Effects of rearing density on growth and survival of the polychaete rockworm Marphysa sanguinea have been investigated in order to develop rearing techniques for this species. This study was examined over a nine-month period in the Fisheries Science and Technology Center of Pukyong National University. Three rockworm densities, 500, 1,000 and $2,000worms{\cdot}m^{-2}$ with weight ranges of < 0.5 g, 0.6-1.5 g, and 1.6-2.5 g, and the no feed control treatment, were stocked in triplicate $0.10m^2$ boxes with sand bottoms. Growth rates were checked with 15 randomly sampled rockworms from each box at months 3, 6 and 9. Results showed that SGRs in all treatments were higher during the first period (0-3 months) than the second (3-6 months) and third periods (6-9 months) for all treatment densities, while SGRs decreased with increasing density. However, survival and growth of worms at high density was not better than low density, but daily biomass production in medium and high density groups was $6.28gm^{-2}day^{-1}$ for the rockworms of 0.6-1.5 g with $2,000inds{\cdot}m^{-2}$, and $12.6gm^{-2}day^{-1}$ for group between 1.6-2.5 g with $2,000inds{\cdot}m^{-2}$, and $14.7gm^{-2}day^{-1}$ for the group of individuals <0.5 g with $1,000inds{\cdot}m^{-2}$. Results showed that M. sanguinea can be one of the most suitable species to commercially exploit in a farming system. In particular, specified densities permit elevated pure production.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.4
• /
• pp.549-554
• /
• 2016

The present study was conducted to investigate whether dietary essential oils could affect growth performance, relative organ weights, cecal microflora, immune responses and blood profiles of broiler chickens fed on diets containing different nutrient densities. A total of eight hundred-forty 1-d-old male broiler chicks were randomly allotted into twenty-eight pens (7 pens per treatment, 30 chicks per pen). There were four experimental diets containing two different nutrient densities and supplemented with or without essential oils. Experimental period lasted for 35 days. No clear interaction between nutrient density and essential oils on any of growth performance-related parameters was observed. Live body weights were affected (p<0.05) by nutrient density at 21 days and by dietary essential oils at 35 days. Essential oils significantly (p<0.05) increased daily body weight gain and feed conversion ratio during the periods of 22 to 35 and 1 to 35 days, but failed to affect feed intake during the entire experimental period. Daily weight gain at 1 to 21 days and feed intake at 1 to 21 and 1 to 35 days were significantly impaired (p<0.05) by nutrient density. There were significant treatment interactions (p<0.05) on relative weights of bursa of Fabricius and abdominal fat contents. Finally, either essential oil or nutrient density did not influence the relative percentages of breast and leg meats, the population of cecal microflora, blood parameters and antibody titers against Newcastle disease and infectious bronchitis in broiler chickens. It was concluded that dietary essential oils, independent to nutrient density, failed to stimulate feed intake, but increased growth performance in broiler chickens.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.3
• /
• pp.251-258
• /
• 2011

To investigate whether the rearing environmental factors (size heterogeneity, rearing density, and feeding frequency) affect the growth and cannibalism of fry in cultured puffer Takifugu obscurus, we conducted three experiments. To examine size effects, we used small (total length [TL] $26.0{\pm}0.5\;mm$, body weight [BW] $0.18{\pm}0.01\;g$), medium (TL $23.1{\pm}0.1\;mm$, BW $0.28{\pm}0.01\;g$), large (TL $26.0{\pm}0.2\;mm$, BW $0.48{\pm}0.01\;g$) and small-large size combination groups. For density, we used size-matched puffers (TL $25.0{\pm}0.5\;mm$, BW $0.53{\pm}0.03\;g$) and five density were examined ranging from 1.43 to 7.14 individuals/L. For the feeding frequency, we also used size-matched fry and feeding frequencies of three times/2 days, one time/day, two times/day, three times/day. We ran each experiment in triplicate and investigated the survival rate, daily food intake (DFI), feed efficiency (FE), and daily growth rate (DGR). The growth of the puffers increased with increasing size, density, and feeding frequency, while cannibalism increased with a greater size gap, density and lower feeding frequency. Therefore, we concluded that size, rearing density, and feeding frequency are major factors influencing growth and cannibalism of the puffer, T. obscurus.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.1
• /
• pp.58-63
• /
• 2011

This study investigated the effects of stocking density and feeding frequency (three and five times per week) on the growth of Pacific cod, Gadus macrocephalus. In the first experiment, experimental groups of fish (mean weight $167.8{\pm}41.4\;g$) were reared at three stocking densities (4, 8 and 12 kg/$m^3$) for 16 weeks. The total weight gain was 17.8, 17.1 and 35.4% at 4, 8 and 12 kg/$m^3$, respectively. The specific growth rates, survival rates and feeding efficiency increased with the density, but there were no significant differences (P>0.05). The daily feed intake decreased as the stocking density increased, whereas the condition factors increased with the stocking density (P<0.05). In the second experiment, groups of fish ($194.1{\pm}68.3\;g$) were fed either three or five times a week. The total wight gain was 14.4 and 18.5% for the fish fed three and five times per week, respectively. The specific growth rates of Pacific cod fed to satiation increased with the feeding frequency, although the difference was not significant (P>0.05). The survival rates, daily feed intake, feed efficiency, and condition factors of the Pacific cod were not significantly different (P>0.05). Based on these results, the optimum stocking density for juvenile cod is above 12 kg/$m^3$, and the best feeding frequency is three times a week, under the conditions used in this experiment.

• Korean Journal of Plant Resources
• /
• v.14 no.3
• /
• pp.196-205
• /
• 2001

The results of examining cultivation of tlyster mushroom using NSM(Non Sterilized Media) for determining the condition of artificially culturing oyster mushroom(Pleurotus ostreatus) are as follows. Mycelial growth an[1 density of oyster mushroom. were the highest in the medium of waste cotton(spinning) : corn cob(80 : 20, V/V) followed by the order of rice bran, beet pulp. Expecially, mycelial growth and density of oyster mushroom is the lowest at the mixture rate of 80% waste cotton(spinning) : 10% beet pulp. Mycelial growth and density of oyster mushroom. were the highest in the medium of cotton seed hull and beet pulp mixture followed by the order of rice bran, corn cob. Expecially, mycelial growth and density of oyster mushroom is the lowest at the mixture rate of 80% cotton seed hull : above 20% rice bran. Mycelial growth and density of oyster mushroom were the highest in the medium rate of 70% waste cotton(spinning), 10% corn cob and 10% beet pulp(V/V). Mycelial growth and density of oyster mushroom were the highest in the medium rate of 70% cotton seed hull , 10% corn cob and 10% beet pulp(V/V). Optimal concentration of NSM for the mycelial growth and density of oyster mushroom were shown to be 500 times concentration. Optimal water contents for the mycelial growth and density of NSM was 70%.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.11 no.3
• /
• pp.102-109
• /
• 2002

The fatigue crack growth under mixed mode condition has been discussed within the scope of linear fracture mechanics such as maximum tangential stress, maximum tangential principal stress and minimum strain energy density. The purpose of this study is to investigate the characteristics of fatigue test crack growth in 304 stainless steel under mixed node. The fatigue test results carried out by using inclined pre-crack specimens was compared to both of the theoretical predictions of the criteria, maximum tangential stress and stain energy density. As difference from theoretical analysis, the transition region from mixed mode to mode I appeared in the fatigue test. There is deep relationship between the angle of slanted pre-crack and transition. Therefore, as applying the different stress intensity factor to each node I+II and mode I, the directions and rates of fatigue crack growth are evaluated more accurately under mixed mode.

• Journal of Environmental Health Sciences
• /
• v.22 no.3
• /
• pp.49-55
• /
• 1996

Water parsley(Oenanthe javanica(Blume) DC) was raised with varying population density(S) in the laboratory aquarium unit to determine the growth equation. The population density was measure after 7 days. The resultant growth curve was well fit to the equation 1/S = A+B (1/S0) with a high correlation coefficient ($R^2$ = 0.999). The maximum specific absorption rate was $9.011 \times 10^{-5}$ kg $NO_x-N/kg$ water parsley$\cdot$day and $1.31 \times 10^{-5}$ kg $PO_4-P/kg$ water parsley$\cdot$day when the average population density was $2.62 kg/m^2$. The relationship between population density and nutrient absorption rate, the absorption rate of $NO_x-N$ was 5.04~5.24 mg/l$\cdot$day when the population density was $7.51~10.0 $mg/m^2\cdot day$ and the absorption rate of $PO_4-P$ was 0.56~0.78 mg/l$\cdot$day when the population density was 5.02~10.0 $kg/m^2\cdot day$. Taking into account the nutrient absorption rate and growth rate, the population density between $7.0 kg/m^2\cdot day$ and $8.0 kg/m^2 \cdot day$ was selected. The removal rate of nutrient was investigated after 7 days culture. Removal rate of $NO_x-N$ was 95.6~99.95% with initial concentration of 35 mg $NO_x-N/l$, and the removal rate of $PO_4-P$ was also high, indicating 80.24~98.9% with initial concentration of 5.95 mg $PO_x-P/l$.

• Korean Journal of Plant Resources
• /
• v.12 no.2
• /
• pp.152-160
• /
• 1999

Bacterial population density on soybean leaves was $10^2~10^5CFU/cm^2$. Bacterial population density was increased by progress of plant growth stage. Population density of soybean sprout rotting bacteria on soybean leaves was $0~10^3CFU/cm^2$. Population density of soybean sprouts rotting bacteria was related to cultivating area, but not related to plant growth stage. Cultivar and population density of soybean sprout rotting bacteria were less corelated, and varied by plant growth stages and plant parts. Erwina cypripedii, E. carotovora subsp. carotovora, Xanthomonas campestris pv. glycines, Staphylococcus sp., and Micrococcus sp. were identified as pathogenic bacteria causing soybean sprout rot. In generally population density of E. cypripedii, E. carotovora subsp. carotovora, Micrococcus sp., and X. campestris pv. glycines were high.

• Mycobiology
• /
• v.36 no.1
• /
• pp.34-39
• /
• 2008

Schizophyllum commune is an edible and medicinal mushroom widely distributed in the world. The optimal growth conditions for the mycelia of 10 strains of the fungus were investigated. The temperature suitable for the mycelial growth and density was obtained at $30{\sim}35^{\circ}C$. Among the tested conditions, the minimum mycelial growth was found at $15^{\circ}C$. In case of pH, the most favorable growth was found at pH 5. The results indicated that this mushroom well adapted to high temperature and low pH for its mycelial growth. Considering growth phenotype of mycelia, Hamada, Hennerberg, PDA and YM were the most suitable and Lilly, Glucose triptone, Glucose peptone and Hoppkins were the most unfavorable among tested media for the mycelial growth of S. commune. Out of tested carbon sources, dextrin and fructose were the most suitable and lactose, mannose and sorbitol were the unsuitable for the fungus. Compact mycelial density was obtained from most of the carbon sources. Among used nitrogen sources, calcium nitrate, potassium nitrate and alanine were the most appropriate and the most incompatible were ammonium phosphate, histidine, urea and arginine for mycelial growth of S. commune on the culture media. Calcium nitrate, histidine and potassium nitrate showed moderately thin or thin, and rest of nitrogen sources showed compact or moderately compact mycelial density.