• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권1호
• /
• pp.123-128
• /
• 2013

Water quality and contamination of sediment is a growing concern in the Iksan stream of Korea. Heavy metal contamination and changes in the physicochemical properties of the stream were evaluated. Water and sediment samples were collected from six sites during the dry and rainy seasons; pH, DO, EC, ORP, turbidity, $PO_4$-P, $NO_3$-N and selected heavy metals (Cu, Pb, Ni, As, Zn, Cd, Hg) were measured. Results showed almost no change in pH between seasons. DO was highest at site 2 (~2.63 mg/L) in the dry season; EC (1,540 ms/m) was greatest at site 1 in both seasons. The ORP gradually increased from the dry to rainy season at most of the sites and was highest at site 5. Turbidity was highest at site 1 and gradually decreased from the dry to rainy season at all sites except site 3. $PO_4$-P ranged from a high of 1,193mg/L at site 1 to in the dry season to a low of ~1.2 mg/L at site 4. In contrast, $NO_3$-N was highest at site 3 in the rainy season (12,531 mg/L). Among the heavy metals measured, Cu and Zn concentrations were highest at all sediment sites. Cu and Zn are added to livestock feed to improve reproductive rates and can be carried to the stream with manure. Transport of sediment and heavy metals during the rainy season is the major source of stream contamination and it is important to continue monitoring and take necessary action in these areas.

• 한국정밀공학회지
• /
• 제29권12호
• /
• pp.1272-1278
• /
• 2012

The micro barrier rip array structures have been applied in a variety of areas including as privacy films, micro heat sinks, touch panel and optical waveguide. The increased aspect ratio (AR) of barrier rip array structures is required in order to increase the efficiency and performance of these products. There are several problems such as burr, defect of surface roughness and deformation and breakage of barrier rip structure with machining high-aspect ratio micro barrier rip array structure using orthogonal cutting method. It is essential to develop technological methods to solve these problems. The optimum machining conditions for machining micro barrier rip array structures having high-aspect ratio were determined according to lengths ($200{\mu}m$ and $600{\mu}m$) and shape angles ($2.89^{\circ}$ and $0^{\circ}$) of diamond tool, overlapped cutting depths ($5{\mu}m$ and $10{\mu}m$), feed rates (100 mm/s) and three machining processes. Based on the optimum machining conditions, micro barrier rib array structures having aspect ratio 30 was machined in this study.

• Asian-Australasian Journal of Animal Sciences
• /
• 제3권4호
• /
• pp.269-279
• /
• 1990

A 98 d feeding trial carried out to study liveweight change and rumen metabolites in heifers weighing initially 275 kg and given either untreated or ammoniated rice straw supplemented with 0, 0.4, 0.8 or 1.2 kg protein meal consisting of cottonseed meal (60). All 32 animals received 0.6 kg rice polishings/hd/d and had continuous access to molasses/urea block-licks containing 15% urea. The effects on growth rates of treatment of the straw with ammonia and of supplementation with bypass protein were additive. The heifers fed ammoniated straw grew 267 g/hd/d (p<0.001) faster and consumed 11% (p<0.05) more straw than the heifers on untreated straw. The mean growth response to bypass protein was 0.37 kg gain/kg protein meal supplied. Supplementation with protein meal tended (p=0.06) to depress intake of straw, but straw intakes of the unsupplemented groups were high. Small changes in the composition of the block-licks that were fed throughout the feeding trial led to changes in block intake and in intake of untreated straw. Increasing quantities of protein meal fed were associated with linear increase in concentrations of ammonia (p<0.05) and in molar percentages of iso-butyrate (p<0.01), iso-valerate (p<0.01) and valerate (p<0.01) in the rumen fluid of the heifers on a basal diet of untreated straw. However, in the rumen fluid of the heifers given ammoniated straw, the levels of these metabolities were not affected by the quantity of protein meal given.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권7호
• /
• pp.1003-1010
• /
• 2003

The effects of different rumen protected forms, oleamide, Ca oleate, of dietary oleic acid on the carcass quality and fatty acid composition in intramuscular and subcutaneous fat tissues of Hanwoo steer were examined. Sixty, 25 month old Hanwoo steers divided into three groups were fed no supplement (Control), 2% of oleamide (Oleamide) or Ca-oleate (Ca-Oleate) in their diet for 45 or 90 days. Disappearance rates of oleic acid supplements in digestive tracts (Rumen bypass, abomasal and intestinal disappearance rate) were 48.5, 68.4 for oleamide and Ca oleate, respectively. Both oleic acid supplements affected feed intake, growth rate, cold carcass weight and carcass fatness. Live weight gain, carcass weight, backfat thickness and marbling score were higher in the oleic acid supplemented steers compared with those from the control. Oleic acid supplements increased marbling score and ether extract in Hanwoo steer m. logissi thoracicmus. Rumen protected oleic acid increased not only the level of oleic acid but also polyunsaturated fatty acids in intramuscular and subcutaneous fat tissue. Total saturated fatty acid contents in both fat tissues were decreased whereas total unsaturated fatty acid content was increased compared with those from control. Linoleic acid, linolenic acid and polyunsaturated fatty acid contents were significantly higher in Ca oleate than any other steers. Lipid metabolites in blood were increased in rumen protected oleic acid treatments. HDL content in blood was increased in Ca-oleate supplemented steers whereas LDL was decreased compared with control. The changes of fatty acid compositions in the rumen protected oleic acid supplemented steers suggest that the oleic acid and unsaturated fatty acid were protected from rumen biohydrogenation and can be deposited in the fat tissues.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제40권1호
• /
• pp.16-21
• /
• 2020

Humans use insects as food and traditional medicine for many years. Hemolymph is the circulating fluid of insects and is a key component of their immune system. However, limited information is available regarding hemolymph identification, development, and differentiation, as well as the related cellular immune responses. In a previous study, hemolymph extracts prepared from Bombyx mori larvae were found to exert anti-inflammatory effects. In this study, we aimed to identify and compare the antioxidant activity of immune-challenged and unchallenged B. mori hemolymph extracts in vitro. For this purpose, human epithelial Caco-2 cells were first exposed to oxidative stress and then treated with various concentrations and incubation times of either immune-challenged or unchallenged B. mori hemolymph extracts. Next, we determined the effect of treatment on the relative expression of GPX-1, SOD-1, and SOD-2 antioxidant marker genes. We found that the expression rates of the three marker genes were markedly higher at a immune-challenged hemolymph extract concentration of 80 ppm compared to those at other concentrations, and the antioxidant effects were enhanced after treatment for 48 hr. Thus, B. mori hemolymph extracts showed antioxidant activity within the limited time and dose. Especially, the immune-challenged B. mori hemolymph extracts showed higher the antioxidant activities than unchallenged one. The activity of silkworm hemolymph extracts could facilitate the development of new types of functional foods, feed additives, and biomaterials with antioxidant properties.

• 공업화학
• /
• 제8권5호
• /
• pp.837-843
• /
• 1997

산화형 폴리에틸렌 왁스 제조에 있어서 주요 반응인자인 사용 왁스의 물성, 산화시간, 산화온도, 공기의 주입량 등에 따른 산가의 변화와 산화에 따른 폴리머의 물성을 분석하였다. 실험결과 주어진 반응조건 하에서 산화온도에 대한 산가의 변화는 $160^{\circ}C$까지는 증가하였지만 $170^{\circ}C$에서는 오히려 산가가 감소하는 경향을 보였고, 공기 주입량에 비례하여 산가는 증가하였다. 또한 사용한 왁스의 분자량이 낮을수록 산가가 높았다. 분자량과 밀도차가 공존하는 시료의 산화반응에서는 가지의 길이, 수 등에 의한 밀도보다는 분자량에 의한 영향이 큰 것으로 생각되었다. 산화가 진행됨에 따라 분자량은 감소하고 분자량 분포는 넓어짐을 알 수 있었다. 온화한 조건 하에서 고산가를 얻기 위하여 자유라디칼 개시제를 촉매로 사용하였는데 같은 조건 하에서 무촉매인 경우에 비하여 고산가의 산화형 왁스를 얻을 수 있었다. 또한 DCPO(dicumylperoxide), HOPO(t-butyl peroxy 2-ethyl heaxanoate), BPO(butylperoxide) 순의로 반감기가 긴 촉매가 효율적이었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제26권7호
• /
• pp.945-951
• /
• 2013

In vitro studies were undertaken to develop an appropriate fibrolytic enzymes cocktail comprising of cellulase, xylanase and ${\beta}$-D-glucanase for maize stover with an aim to increase its nutrient utilization in sheep. Cellulase and xylanase added individually to ground maize stover at an increasing dose rates (0, 100, 200, 400, 800, 1,600, 3,200, 6,400, 12,800, 25,600, 32,000, 38,400, and 44,800 IU/g DM), increased (p<0.01) the in vitro dry matter digestibility and in vitro sugar release. The doses selected for studying the combination effect of enzymes were 6,400 to 32,000 IU/g of cellulase and 12,800 to 44,800 IU/g of xylanase. At cellulase concentration of 6,400 IU/g, IVDMD % was higher (p<0.01) at higher xylanase doses (25,600 to 44,800 IU/g). While at cellulase doses (12,800 to 32,000 IU/g), IVDMD % was higher at lower xylanase doses (12,800 and 25,600 IU/g) compared to higher xylanase doses (32,000 to 44,800 IU/g). At cellulase concentration of the 6,400 to 32,000 IU/g, the amount of sugar released increased (p<0.01) with increasing levels of xylanase concentrations except for the concentration of 44,800 IU/g. No effect of ${\beta}$-D-glucanase (100 to 300 IU/g) was observed at lower cellulase-xylanase dose (cellulase-xylanase 12,800 to 12,800 IU/g). Based on the IVDMD, the enzyme combination cellulase-xylanase 12,800 to 12,800 IU/g was selected to study its effect on feed intake and rumen fermentation pattern, conducted on 12 rams (6 to 8 months; $20.34{\pm}2.369$ kg body weight) fed 50% maize stover based TMR. The total volatile fatty acids (p<0.01) and ammonia-N concentration was higher in enzyme supplemented group, while no effect was observed on dry matter intake, ruminal pH and total nitrogen concentration.

• Asian-Australasian Journal of Animal Sciences
• /
• 제33권5호
• /
• pp.856-865
• /
• 2020

Objective: This study was conducted to evaluate the physicochemical properties and changes in moisture concentrations of bedding materials under the conditions of rearing Korean Hanwoo cows. Methods: Two experiments were conducted to investigate the physicochemical characteristics (Exp. I) and usefulness as beddings for rearing cattle (Exp. II) by the type of beddings such as sawdust (SD), wood shavings (WS) and sawdust+wood shavings (S+W; 1:1 in volume), and the species of pine trees from different countries of origins (China, Pinus armandii, AR; Vietnam, Pinus kesiya, KE; USA, Pinus rigida, RI). Results: In Exp. I, SD-AR showed the largest proportion (78.3%) of fine particles (250 ㎛+below 250 ㎛) and the highest bulk density (208 kg/㎥) among treatments (p<0.05). The water absorption capacity at 24 h of both S+W-RI (713%) and -KE (701%) was the highest among treatments (p<0.05) and higher than those of SD or WS alone within each species of pine tree (p<0.05). Moisture evaporation rates (%) at 12 h were ranged from 52.3 to 60.8 for SD, 69.9 to 74.4 for WS, and 72.3 to 73.5 for S+W. Total amounts (mg/㎡) of ammonia emissions were the lowest (p<0.05) in KE species among the pine species within each type of bedding material, having higher ability of ammonia absorption. In Exp II, KE species in both side A and B had lower moisture concentrations (%) than other species. Regardless of types of beddings except SD-AR, moisture concentrations of beddings within a pen were higher (p<0.01) at side A than B. Conclusion: The KE species has better physical characteristics than other beddings and more useful for rearing Hanwoo cattle than other beddings, probably caused by the differences in the method and degree of wood processing rather than the species.

• 한국발생생물학회지:발생과생식
• /
• 제6권2호
• /
• pp.83-88
• /
• 2002

월동기 90일 동안 transgenic coho salmon의 사료섭식량, 성장도 및 혈중 호르몬 수준을 파악하였다. 실험 종료시 실험구별 사료섭식량은 비교해 볼 때 tGH구가 Wild구보다 약4배 정도 높게 나타났지만, 사료효율의 경우 오히려 tGH구가 Wild구보다 1.1 배 낮은 것을 알 수 있었다. 한편 생존률은 tGH구가 Wild구보다 높게 나타났고, 성장은 tGH구가 길이에 있어 1.4배, 무게의 경우 약 3배 빠르게 나타났으며, 비만도 역시 tGH구가 Wild구보다 높게 나타났다. 실험구별 성장에 따른 호르몬 분석 결과, GH와 thyroid hormone의 농도는 tGH구가 Wild구에 비해 약 2배 정도 높은 값을 나타냈었다. 실험구별 형태적 특징을 관찰해 본 결과, tGH구들은 Wild구와 비교해 머리가 몸에 비해 상대적으로 크면서 꼬리지느러미의 가랑이 부분이 중심선으로 위, 아래가 확연히 분리되어 있지 않았다. 또한 몸통 부분은 길이에 비해 상대적으로 체고가 높게 나타났다.

• 한국가금학회지
• /
• 제24권2호
• /
• pp.85-90
• /
• 1997

An experiment was conducted to investigate the relationship between blood hormone levels and light cycle on performance of Korean native chicken. One hundred and two Korean native chickens were grouped into three treatments of natural light cycle (Control), 13L:11D (T2), and 16L:8D (T3). The egg production, egg weight, feed intake, serum melatonin and estrogen level were periodically measured from 22 to 34 weeks, respectively. The laying rates of T2 and T3 were significantly higher than that of the Control (P