• Korean Journal of Poultry Science
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• v.6 no.2
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• pp.91-102
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• 1979

The basic problem of the broiler industry is that of fluctuating prices, mainly thanks to unstable supply of and inelastic demand for products as usually indicated as a peculiarity of agricultural commodities. This particularly brings the producer to a great economic risk, because he has to sell products under the condition of pure competition, whereas others from whom he has to buy deal under the condition of oligopoly or even monopoly. Therefore, producers economic position is generally placed in the worst comparing others dealing with, which results in unbalanced economic status of elements involved in broiler operation and further obstruction of industry development as a whole. A certain type of business coordination to overcome such a problem should be measured in order to improve the efficiency of entire operation and thus assure the balanced industry development. The concept of the economic integration developed in modern business system had been adapted to U.S. poultry industry which became common later around the world as a means of stabilizing producers price and whole industry as well. There are two main typos of integration; horizontal and vertical The former refers to the general grouping of similar business units, eg. a hatchery tying with other hatchery, while the latter refers to the knitting together of two or more stages of economic activities, eg. tying together among units of hatching, fled milling, production, processing and marketing. By having the industry integrated, risk and uncertainty involved in various stages of operation could be diversified. The typo of integrating contract between producers and integrators include the share of profits, flat fee payment, feed conversion payment and salary basis. In the U.S., extensive changes in production, processing, and marketing during the last few decades have changed the thicken broiler industry from one of small, widely scattered farms to one that is largo, concentrated and efficient. More than 99 percent of all broilers produced are grown under contract and by integrated firms which vary in size of operation and complexity. About 84 percent of all production is concentrated in 10 States. Some of the other factors ;hat contributed to these choses arc costs, energy use, prices, processing, marketing and demand. No integrated broiler production system has yet been applied in Korea's poultry industry, thus all stages all broiler operation run independently seeking for its own profit. Consequently, producers price fluctuate very widely around the year even more than 50 percent in a few months. This also leads to disadvantages of material supplies, processors and distributors and enforce the industry unstable. The current economic environment in Korea seems that the time for broiler integration comes and as an ideal integrator, feed millers, food processors and producers group may be considered.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.5
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• pp.481-488
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• 2013

Nitric oxide ($NO_x$) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of coflow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the $NO_x$ emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the $NO_x$ emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the $NO_x$ emission in the condition of oxyfuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of $NO_x$ formation for various oxidizer compositions, 1D and 2D numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2D simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured $NO_x$ emissions.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.28-37
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• 1996

Benzidine, an aromatic amine used primarily in the manufacture of azo dyes, is recognized as a urinary bladder carcinogen in humans. In rats, mice, and hamsters, chronic exposure to benzidine resulted in tumors of the liver. The present study was undertaken to suggest analyzing the metabolites of benzidine with the optimal condition, identify the metabolites of benzidine, and observe time variance of the metabolites in the isolated perfusated rat liver. N-acetylbenzidine was synthesized by acetylation of benzidine with acetic anhydride and separated by thin layer chromatography(TLC) and high performance liquid chromatography(HPLC). To analysis benzidine and the metabolites of benzidine, HPLC operating condition has been optimized by means of preliminary experiment. The mobile phase consisted of acetonitrile(37%) in phosphate buffer, flow rate maintained at 1.0 ml/min. Optimal detective conditions were electrochemicaldetector(ECD) at 0.75 V for benzidine and N-acetylbenzidine and ultravioletdetector(UVD) at 287 nm for N,N'-diacetylbenzidine. The separation system was composed of a guard column and a separation column(Polymer C18, $4.6{\times}250cm$) at a temparature of $40^{\circ}C$. The perfusion system was equilibrated for 30 minutes before addition of benzidine to the perfusate. Samples of the perfusate were collected at time intervals(0, 10, 20, 30, 60, 90, 120 min) during the 2 hour perfusion. Before analyzing samples by HPLC/ECD/UVD, samples had been treated with sep-pak. Samples of perfusate analyzed by HPLC/ECD/UVD and the metabolites of benzidine in the isolated perfused rat liver were N-acetylbenzidine and N,N'-diacetylbenzidine. Benzidine metabolized over 60% during the initial 30 minutes of perfusion, extensively by 1 hour, and was undetectable in the perfusate. N-acetylbenzidine increased by 30 minutes of perfusion, declined. N,N'-diacetylbenzidine increased the 0-90 minutes period, remained constant during the 90-120 minutes period.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.467-474
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• 2012

This study was carried out to evaluate effect of temperature condition on nitrogen mineralization of organic matter, distribution of microbial group by PLFA profiles, and soil microbial community structure in volcanic ash soil. Dried soil 30 g mixed well each 2 g of pellet (OFPE) organic fertilizers, pig manure compost (PMC), and food waste compost (FWC). And then had incubated at $10^{\circ}C$, $20^{\circ}C$, and $30^{\circ}C$, respectively. Nitrogen mineralization rate increased with increasing temperature and that was in the order of FWC>OFPE>PMC. Distribution ratio of microbial group by PLFA profiles were different significantly caused by incubation temperature and the type of organic matter. As incubating time passed, density of microbial group decreased gradually. The Gram-bacteria PLFA/Gram+ bacteria PLFA, Fungi PLFA/Bacteria PLFA, and Unsaturated PLFA/saturated PLFA ratios were decreased according to the increasing temperature gradually. But cy19:0/$18:1{\omega}7c$ ratio increased both FWC and PMC treatment. Principal component analysis using PLFA profiles showed that microbial community structure made up clearly at both 75 days ($10^{\circ}C$) and 270 days ($30^{\circ}C$) by temperature factor. As incubating time passed, microbial community structure shifted gradually.

• Journal of Korean society of Dental Hygiene
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• v.9 no.1
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• pp.125-139
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• 2009

Objective : This study was performed in order to provide basic data for halitosis prevention and establish a device to efficiently eliminate halitosis and to analyze the factors that affect the halitosis. Methods : Oral examination on the Gingival index, CPITN, Tongue Plaque index, and OHI-S as well as halitosis measurement among 293 rural residents. Results : Gingival index was high at mild on female and at moderate on male(p=0.025). Sorting the result by age, mild was 54.1% in the 40s, and moderate was 49.5%, 42.0% and 70.0% each in the 50s, 60s, and the 70s(p=0.005). The need for dental plaque management was 100%. The need for scaling was high with 78.3%, 93.0%, 89.9%, and 90.0% each for the 40s, 50s, 60s, and 70s. The need for complex periodontal treatment was also high with 32.4%, 47.5%, 48.7% and 60.0%, each for the 40s, 50s, 60s, and 70s(p=0.050). The highest bad condition for OHI-S was 69.5%, and good being 18.9%, and very bad being 11.6%. For moderate tongue plaque index was 74.4% as the highest. As the level of education increased, the slight tongue plague was increased, but in contrast, the moderate and higher tongue plague index was decreased(p=0.010). OG under 50ppm was 61.1% on male and OG over 50ppm was 50.9% on female(p=0.041). In OG over 50ppm, CPITN was 52.1% and 41.9% in scaling and complex periodontal treatment group(p=0.018). OHI-S, in bad and very bad condition with OG, over 50ppm, was 48.7% and 46.9%(p=0.019). The higher tongue plague index showed significant amount of increase at OG and EG above 50ppm(p=0.006). $NH_3$, as the tongue plaque index increased, the wider range of distribution was shown(p=0.000). As for the multiple regression analysis result, there have been selected females and tongue plaque index as factors affecting OG. There have been selected age and tongue plaque index as factors affecting EG and there have been selected females as factors affecting on $NH_3$. Conclusions : With the aforementioned results in mind, the status of halitosis among rural residents is considered to bare a close relation with oral environments. we have to focus on correct tooth brushing methods and tongue brushing, with using tongue cleaner to remove fur of tongue plaque. Also, in order to analyze exactly the factors of individual halitosis, we need continuous and systematic study.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.841-845
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• 2003

In order for engineered tissues to find clinical utility, the engineered tissues must function appropriately. However, smooth muscle (SM) tissues engineered in vitro with a conventional tissue engineering technique may not exhibit contractile functions, because smooth muscle cells (SMCs) cultured in vitro typically revert from a contractile, differentiated phenotype to a synthetic, nondifferentiated phenotype and lose their ability to contract. SMCs in vivo typically reside in mechanically dynamic environments. We hypothesized that cyclic mechanical stretch induces the features of SMCs in in vitro engineered tissues to be similar to those of SMCs in native tissues. To test the hypothesis, aortic SMCs were seeded onto elastic, three-dimensional scaffolds and cultured in vitro under a cyclic mechanical stretching condition for 4 weeks. A significant cell alignment in a direction parallel to the cyclic stretching direction was found in the SM tissues exposed to cyclic stretching. The cellular alignment and alignment direction were consistent with those of native vascular SM tissues, in which SMCs in vivo align in the radial direction (parallel to stretching direction). In control tissues (SM tissues engineered without stretching), cells randomly aligned. The expression of SM ${\alpha}-actin$ and SM myosin heavy chain, phenotypic markers of SMCs in a contractile state, was upregulated in the stretched tissues by 2.5- and 2.0-fold, respectively, compared to SMCs in the control tissues. The cellular features of alignment and contractile phenotype of SMCs in the SM tissues engineered under a mechanically dynamic environment could allow the engineered SM tissues to exhibit contractile functions.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.362-367
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• 2006

Waste activated sludge(WAS) collected from domestic wastewater treatment plant is biomass that contains large quantities of organic matter. However, relevant literature show that the bio-hydrogen yield using WAS was too low. In this study, the effect of pretreatment of WAS on hydrogen yield was investigated. Pretreatment includes acid and alkali treatments, grinding, heating, ozone and ultrasound methods. After pretreatment organic matters of WAS were solubilized and soluble chemical oxygen demand(SCOD) was increased by 14.6 times. Batch experiments were conducted to investigate the effects of pre-treatment methods and buffer solution, hydrogen partial pressure, and sodium ion on hydrogen production from WAS by using heated anaerobic mixed cultures. Experimental results showed that addition of buffer solution, efficient pre-treatment method with alkali solution, and gas sparging condition markedly increased the hydrogen yield to 0.52 mmol $H_2/g$-DS.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.8
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• pp.564-571
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• 2011

In order to establish fundamental data for stream restoration and environmental flow, we investigated fish fauna, community and physical habitat conditions in the Dal Stream of Han River Basin. Field monitoring including fish sampling was conducted from September 2008 to October 2009. A total number of fish caught in the 5 sites was 2,080 representing 9 families 35 species, and 19 species (54.3%) including Acheilognathus koreensis and Iksookimia koreensis were Korean endemic species during the study period. The most frequently found species in number was pale chub (Zacco platypus, 25.7%, n = 632) followed by Coreoleuciscus splendidus (18.0%, n = 375) and Z. koreanus (13.0%, n = 272). The lower reach of Dal Stream was more abundance of species, high diversity, evenness and richness, and lower dominance index than those of the upper reach. According to the dendrogram established at 0.63 level of similarity rate, sampling stations were divided into 2 groups. Most of upper streams in Korea consist of riffles and runs that are repeatedly followed by another one. However, stream channelization and leveling have caused reduction of habitat diversity. Therefore, it is necessary to make an effort on stream rehabilitation with evaluation of physical habitat condition by indicator species in order to maintain biodiversity and perform ecological restoration.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.140-145
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• 2000

This study was performed to investigate whether the earthworm cast could be reused as bulking agent in the whole processing of the food wastes using the earthworm. In addition, the growth conditions of microorganism lived upon earthworm lasts was investigated. Because the raw food wastes used in this experiment had low pH, and high moisture and organic matter contents, it was unsuitable to use as direct feeds to earthworm. However, when the food wastes were mixed with some earthworm cast, the mixtures were suitable to the feed condition and the growth environment of the earthworm. Therefore, it shows the possibility that the earthworm cast be reused as bulking agent for food wastes. In the microbiological investigation on earthworm cast, the bacteria showed most high density among the microbial species. And the microbial density showed higher under the mid-temperature than under high-temperature, and higher under the anaerobic than the aerobic condition. The drying methods of earthworm cast for the moisture adjusting, has no effect on microorganism growth whether natural or artificial drying. And the activity of enzyme presented more highly before the drying than after the drying.

• Journal of Animal Science and Technology
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• v.61 no.6
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• pp.340-351
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• 2019

Hot environments can affect feed intake and lactation, and the subsequent unavailability of important micronutrients to the newborn piglet can impair piglet growth, reduce the viability of newborn piglets and limit their subsequent performance. This work addresses the effects of hot environments (summer season) upon the reproductive performance of sows during gestation and lactation as well as on the serum levels of vitamins and the concentration of immunoglobulins in their litters in comparison with the winter season. Fourteen sows were evaluated over 100 ± 2 days of gestation in each season. The temperature and humidity index (THI) was used as an indirect measure of heat stress during gestation. The reproductive performance, milk yield, and body condition of the sows were recorded. The concentrations of vitamin E and vitamin A in piglets and in sow serum, colostrum, milk and feed were determined by HPLC; immunoglobulins were assessed by an ELISA. The THI index indicated that animals were subject to heat stress only in during the summer. Although the effect was not significant, there were a lower number of piglets at birth and at weaning and the milk yield in summer compared with winter. There was no difference (p > 0.05) in the body condition of sows between seasons. Season had an effect (p < 0.05) on the vitamin A concentration of postpartum sow serum (0.29 ㎍/mL in winter vs 0.21 ㎍/mL in summer) and on the vitamin E concentration before birth (2.00 ㎍/mL in winter vs 0.90 ㎍/mL in summer). Vitamin E in milk was higher (p < 0.05) in winter than in summer (2.23 vs 1.81 ㎍/mL). Serum levels of vitamins A and E in piglets at birth were lower (p < 0.05) in winter than in summer. The concentrations of immunoglobulins (IgG and IgA) in colostrum and milk were similar between seasons (p > 0.05), but the IgA in piglet serum was higher in winter than in summer (p < 0.05). High temperatures produced heat stress in sows, which affected certain aspects of production that can be translated into economic losses for this sector.