• Asian-Australasian Journal of Animal Sciences
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• 제9권1호
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• pp.1-25
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• 1996

The pathogenesis of atherosclerosis can not be summarized as a single process. Lipid infiltration hypothesis and endothelial injury hypothesis have been proposed and investigated. Recent developments show that there are many points of potential interactions between them and that they can actually be regarded as two phases of a single, unifying hypothesis. Among the many risk factors of atherosclerosis, plasma homocysteine and lipoprotein(a) draw a considerable interest because they are independent indicators of atherogenicity. Triglyceride (TG)-rich lipoproteins (chylomicron and VLDL) are not considered to be atherogenic but they are related to the metabolism of HDL cholesterol and indirectly related to coronary heart disease (CHD). LDL can of itself be atherogenic but the oxidative products of this lipoprotein are more detrimental. HDL cholesterol has been considered to be a favorable cholesterol. The so-called 'causalist view' claims that HDL traps excess cholesterol from cellular membranes and transfers it to TG-rich lipoproteins that are subsequently removed by hepatic receptors. In the so-called 'noncausalist view', HDL does not interfere directly with cholesterol deposition in the arterial wall but instead reflects he metabolism of TG-rich lipoproteins and their conversion to atherogenic remnants. Approximately 70-80% of the human population shows an effective feedback control mechanism in cholesterol homeostasis. Type of dietary fat has a significant effect on the lipoprotein cholesterol metabolism and atherosclerosis. Generally, saturated fatty acids elevate and PUFA lower serum cholesterol, whereas MUFA have no specific effect. EPA and DHA inhibit the synthesis of TG, VLDL and LDL, and may have favourable effects on some of the risk factors. Phospholipids, particularly lecithin, have an antiatherosclerotic effect. Essential phospholipids (EPL) may enhance the formation of polyunsaturated cholesteryl ester (CE) which is less sclerotic and more easily dispersed via enhanced hydrolysis of CE in the arterial wall. Also, neutral fecal steroid elimination may be enhanced and cholesterol absorption reduced following EPL treatment. Antioxidants protect lipoproteins from oxidation, and cells from the injury of toxic, oxidized LDL. The rationale for lowering of serum cholesterol is the strong association between elevation of plasma or serum cholesterol and CHD. Cholesterol-lowing, especially LDL cholesterol, to the target level could be achieved using diet and combination of drug therapy. Information on the link between cholesterol and CHD has decreased egg consumption by 16-25%. Some clinical studies have indicated that dietary cholesterol and egg have a significant hypercholesterolemic effect, while others have indicated no effect. These studies differed in the use of purified cholesterol or cholesterol in eggs, in the range of baseline and challenge cholesterol levels, in the quality and quantity of concomitant dietary fat, in the study population demographics and initial serum cholesterol levels, and clinical settings. Cholesterol content of eggs varies to a certain extent depending on the age, breed and diet of hens. However, egg yolk cholesterol level is very resistant to change because of the particular mechanism involved in yolk formation. Egg yolk contains a factor of factors responsible for accelerated cholesterol metabolism and excretion compared with crystalline cholesterol. One of these factors could be egg lecithin. Egg lecithin may not be as effective as soybean lecithin in lowering serum cholesterol level due probably to the differences of fatty acid composition. However, egg lecithin may have positive effects in hypercholesterolemia by increasing serum HDL level and excretion of fecal cholesterol. The association of serum cholesterol with egg consumption has been widely studied. When the basal or control diet contained little or no cholesterol, consumption of 1 or 2 eggs daily increased the concentration of plasma cholesterol, whereas that of the normolipemic persons on a normal diet was not significantly influenced by consuming 2 to 3 eggs daily. At higher levels of egg consumption, the concentration of HDL tends to increase as well as LDL. There exist hyper-and hypo-responders to dietary (egg) cholesterol. Identifying individuals in both categories would be useful from the point of view of nutrition guidelines. Dietary modification of fatty acid composition has been pursued as a viable method of modifying fat composition of eggs and adding value to eggs. In many cases beneficial effects of PUFA enriched eggs have been demonstrated. Generally, consumption of n-3 fatty acids enriched eggs lowered the concentration of plasma TG and total cholesterol compared to the consumption of regular eggs. Due to the highly oxidative nature of PUFA, stability of this fat is essential. The implication of hepatic lipid accumulation which was observed in hens fed on fish oils should be explored. Nutritional manipulations, such as supplementation with iodine, inhibitors of cholesterol biosynthesis, garlic products, amino acids and high fibre ingredients, have met a limited success in lowering egg cholesterol.

• 공업화학
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• 제25권5호
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• pp.447-454
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• 2014

유기태양전지는 제조비용이 저렴하고 플렉서블 전자소자에 적용이 가능하다는 장점들로 인해 최근 많은 연구가 진행되고 있다. 일반적인 정구조의 태양전지(conventional structured solar cell)의 경우 10%대의 향상된 발전 효율을 보이고 있으나, 여전히 기타 Si 및 CIGS 등과 같은 태양전지에 비해 낮은 효율과 짧은 수명은 상용화의 걸림돌로 작용하고 있다. 일반적으로 유기태양전지의 짧은 수명은 유기물의 광산화뿐만 아니라 수분 및 산소에 의한 음극, 양극 소재의 부식으로 인한 소재/소자 열화 문제로 설명되어지고 있다. 한편 이와 같은 문제점을 해결하기 위해 새로운 소자 구조(역구조 태양 전지; Inverted structured solar cell)가 제안되었으며 전자 수송층 및 기능성 계면 소재 연구를 통한 발전 효율 및 수명 향상에 관한 연구가 꾸준히 되고 있다. 그 결과 최근 2D/3D 산화 아연(ZnO) 소재를 역구조 태양전지의 전자 수송층으로 적용하고 건,습식 표면 후처리를 통해 약 9% 수준의 발전효율을 달성하였다. 본 총설에서는 ZnO를 기반으로 하는 전자 수송층 소재의 연구 동향 및 역구조 태양전지의 효율 향상 기술에 관한 최신 연구 동향을 소개하고자 한다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권8호
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• pp.1152-1159
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• 2013

Four male lambs (Katahdin; average live weight $25.9{\pm}2.9$ kg) with "T" type cannulas in the rumen and proximal duodenum were used in a $4{\times}4$ Latin square experiment to evaluate the influence of supplemental dry distillers grain with solubles (DDGS) levels (0, 10, 20 and 30%, dry matter basis) in substitution for dry-rolled (DR) corn on characteristics of digestive function and digestible energy (DE) of diet. Treatments did not influence ruminal pH. Substitution of DR corn with DDGS increased ruminal neutral detergent fiber (NDF) digestion (quadratic effect, p<0.01), but decreased ruminal organic matter (OM) digestion (linear effect, p<0.01). Replacing corn with DDGS increased (linear, $p{\leq}0.02$) duodenal flow of lipids, NDF and feed N. But there were no treatment effects on flow to the small intestine of microbial nitrogen (MN) or microbial N efficiency. The estimated UIP value of DDGS was 44%. Postruminal digestion of OM, starch, lipids and nitrogen (N) were not affected by treatments. Total tract digestion of N increased (linear, p = 0.04) as the DDGS level increased, but DDGS substitution tended to decrease total tract digestion of OM (p = 0.06) and digestion of gross energy (p = 0.08). However, it did not affect the dietary digestible energy (DE, MJ/kg), reflecting the greater gross energy content of DDGS versus DR corn in the replacements. The comparative DE value of DDGS may be considered similar to the DE value of the DR corn it replaced up to 30% in the finishing diets fed to lambs.

• 한국동물위생학회지
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• 제41권3호
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• pp.149-155
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• 2018

Salmonella Enteritidis (S. Enteritidis) are found in animals, humans, and environment. In addition, S. Enteritidis draws attention to the public health concerns due to carriage of antibiotic resistance traits. For these reasons, the prevalence and antibiotic resistance patterns of S. Enteritidis are significant issues with regard to public health. To address this issues, a total of 24 strains of S. Enteritidis from 164 samples collected from several slaughterhouses in Gyeong-Nam province in order for antibiotic resistance profiles. Subsequently, we characterized the genotyping by random amplification polymorphic DNA (RAPD)-PCR. As a result, very high level of resistance to protein synthesis inhibition antibiotics and most isolates were susceptible to others. Six random primers were used for RAPD-PCR to reveal genotypes of S. Enteritidis isolates. One of the primer, P1245, generated 147 distinct RAPD-PCR fragments ranging from 400~3000 bp. The number of RAPD-PCR products ranged from 4 to 8 for this primer. The RAPD-PCR fragments could be placed these strains into 3 subgroups and 2 classes by UPGMA cluster analysis. Interestingly, several S. Enteritidis that isolated from different slaughterhouses showed same genotype. These results showed only limited genetic variation among the isolates, those were grouped into a few different patterns of antibiotic resistance.

• 한국양식학회지
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• 제18권4호
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• pp.293-298
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• 2005

RT-PCR을 이용하여 감성돔의 뇌하수체에서 발현하는 FSH$\beta$와 LH$\beta$ cDNA를 각각 cloning하였다. GenBank를 이용하여 FSH$\beta$와 LH$\beta$ 아미노산 배열과 상동성을 비교한 결과, 감성돔 FSH$\beta$는 참돔 FSH$\beta$와 $83.3\%$, snakehead fish FSH$\beta$와 $79.2\%$ 및 striped bass FSH$\beta$와 $76.0\%$의 상동성이 나타났으며 , 감성돔 LH$\beta$는 yellowfin seabream LH$\beta$와 $97.7\%$, 참돔 LH$\beta$와 $96.2\%$의 높은 상동성을 보였다. 또한, 본 연구에서는 1년생 수컷 감성돔에 GnRHa를 처리한 후, 뇌하수체에서 발현하는 GTH subunit mRNA의 농도와 혈중 T및 혈중 $E_2$ 농도의 변화를 조사하였다. GnRHa를 체중 g당 $0.2\;{\mu}g$으로 복강 주사한 후 0, 6, 12, 24 및 48시간제에 뇌하수체와 혈액을 샘플링한 결과, 호르몬 처리 후 6시간째에 FSH$\beta$ mRNA가 유의적으로 증가하였으나, LH$\beta$ mRNA 발현에는 유의적인 차이가 없었다. 또한 혈중 T와 혈중 $E_2$ 농도는 GnRHa처리 후 24시간째 유의적으로 증가하였다.

• 한국발생생물학회지:발생과생식
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• 제4권1호
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• pp.125-131
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• 2000

Differential display-PCR 방법을 이용하여, hCG 처리에 의한 참돔, Pagrus major의 난성숙 능력의 획득 경과시간에 따라 새롭게 발현하는 cDNA를 해석하였다. Differential display-PCR과 5'RACE 방법을 이용하여, 2,662 염기와 434개의 아미노산을 코드하고 있는 cDNA의 전염기배열을 결정하였다. DNA의 데 이터베이스인 GenBank 및 EMBL을 이용하여 상동성을 검색한 결과, 본 cDNA와 높은 상동성을 나타낸 유전자는 검색되지 않았다. 따라서 본 cDNA는 참돔의 난성숙 능력 유도와 함께 그 발현량이 증가하는 난성숙 관련 유전자로 판단되었다. 또한 본 cDNA에서는 protein kinase C 인산화 및 casein kinaseII 인산화 consensus 배열의 존재가 확인되었다. 본 연구에서 cloning된 난성숙 관련 유전자는 난여포에 hCG 처리 9～24시간 후에 그 발현량이 증가하였으며, GH-II (300 ng/ml)로 배양한 난여포에서 특이적으로 증가하였다. 또한 in vivo 실험에서 난성숙 관련 유전자는 난성숙 능력 획득 이전의 난소에서는 거의 발현하지 않았으나, 난성숙 능력을 획득한 난소에서 강하게 발현된 점으로 보아, hCG에 의한 난성숙 능력 유도에 성숙기간 중 새롭게 합성되는 난성숙 관련 유전자가 관여할 가능성이 높다.

• 생명과학회지
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• 제27권1호
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• pp.72-77
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• 2017

S. Typhimurium SL1344는 성장을 위한 보조인자로 무기철이 요구된다. 철 킬레이트제인 ethylenediamine di-o-hydroxyphenylactic acid (EDDA)가 첨가 된 M9 최소배지에서 S. Typhimurium은 성장에 있어 철 이용이 완전하게 억제된다. 하지만, 세균이나 곰팡이와 같은 미생물들은 철이 부족한 환경에서 제한된 철을 이용하기 위해 사이드로포어를 생산한다. 사람에서 유래한 트랜스페린(hTf)-철 복합체를 M9 배지에 첨가한 조건에서 S. Typhimurium의 사이드로포어 생산은 완전하게 중단되었다. 반면, S. Typhimurium의 성장은 염화철($FeCl_3$)을 첨가한 조건과 동일한 수준으로 유지되었다. 이 결과는 사이드로포어의 생산 없이도 S. Typhimurium이 hTf에 부착된 철을 직접적으로 이용할 수 있다는 것을 알 수 있다. 돌연변이주의 구축과 이를 이용한 분석을 통하여 우리는 세균이 hTf-철 복합체를 직접적으로 이용할 수 있다는 것을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권11호
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• pp.1638-1652
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• 2000

Prolific females require better nutrition and feeding practice because of larger litter size and the substantial decline in body fat. Life-time pig output will be compromised if body protein and fat are not properly managed. First litter females are especially vulnerable because they can loose ${\geq}15%$ of whole-body protein. Conservation of body protein mass during first lactation minimizes wean to estrus interval and increases second litter size (up to 1.2 pigs). The ability to influence litter-size by amino acid nutrition is a new dimension in our understanding. A P2 fat depth below 12 mm at farrow and below 10 mm at wean compromised wean to estrus interval (>2 d) and next litter size (0.5 to 1.5 pigs) in sows. It is now clear that a 'modest' excess of feed during the first 72 h of pregnancy decreases embryo viability so that the potential for an increased litter size at birth is not realized. The capacity for milk production by prolific young sows is 25% higher than the standard used previously (NRC, 1988). First litter females averaged 9.82 kg milk/d for a 21 d lactation. Second and third litter counterparts averaged 10.35 kg/d. Milk production was 95% of peak by 10 d of lactation and sows were in greatest negative energy and lysine balance during the first 6 d. Nearly 45% of the total loss in body protein occurred within the first 6 d, but this could reduced to 30-35% by using a more aggressive feeding strategy after parturition. There appear to be 2 phases in lactation for lysine need (d 2-12 vs 12-21). Feeding to the higher level alleviates the second litter size decline. The lysine requirement for lactation can be predicted with accuracy, but we are not able to predict the second limiting amino acid. Mammary uptake of valine relative to lysine and recent work with practical diets suggest that the recent NRC (1998) pattern is realistic and that threonine and valine could be co-limiting for corn-soy diets for prolific sows nursing 10-11 pigs. Empirical studies are needed to refine the ideal pattern so that synthetic lysine can be used with more confidence. Milk fat output for the elite sow is extraordinary and poses an unnecessarily high energetic cost. Methods that reduce mammary fat synthesis will benefit the sow and may enhance piglet growth.

• 한국재료학회지
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• 제20권7호
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• pp.356-363
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• 2010

For this paper, we investigated the area specific resistance (ASR) of commercially available ferritic stainless steels with different chemical compositions for use as solid oxide fuel cells (SOFC) interconnect. After 430h of oxidation, the STS446M alloy demonstrated excellent oxidation resistance and low ASR, of approximately 40 $m{\Omega}cm^2$, of the thermally grown oxide scale, compared to those of other stainless steels. The reason for the low ASR is that the contact resistance between the Pt paste and the oxide scale is reduced due to the plate-like shape of the $Cr_2O_3$(s). However, the acceptable ASR level is considered to be below 100 $m{\Omega}cm^2$ after 40,000 h of use. To further improve the electrical conductivity of the thermally grown oxide on stainless steels, the Co layer was deposited on the stainless steel by means of an electroless deposition method; it was then thermally oxidized to obtain the $Co_3O_4$ layer, which is a highly conductive layer. With the increase of the Co coating thickness, the ASR value decreased. For Co deposited STS444 with 2 ${\mu}m$hickness, the measured ASR at $800^{\circ}$ after 300 h oxidation is around 10 $m{\Omega}cm^2$, which is lower than that of the STS446M, which alloy has a lower ASR value than that of the non-coated STS. The reason for this improved high temperature conductivity seems to be that the Mn is efficiently diffused into the coating layer, which diffusion formed the highly conductive (Mn,Co)$_3O_4$ spinel phases and the thickness of the $Cr_2O_3$(S), which is the rate controlling layer of the electrical conductivity in the SOFC environment and is very thin

• 기술혁신연구
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• 제22권4호
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• pp.145-164
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• 2014

미래의 궁극에너지로 인식되고 있는 핵융합에너지 개발을 위해서는 DEMO라는 최종 실증 단계를 거쳐야만 한다. 특히 중국, EU, 일본 등의 주요 국가는 DEMO 건설에 대한 구체적 계획을 수립하고 이를 실행 중에 있다. 한국도 1995년부터 KSTAR 사업을 시작으로 핵융합 연구개발에 착수한 점을 감안하면, 핵융합에너지 상용화라는 최종 목표달성 뿐만 아니라, 주요 국가와 DEMO 경쟁 상황에서 주도권을 확보하기 위한 본격적 연구개발이 필요하다. 이에 본 논문에서는 DEMO 개발을 위한 핵심기술을 파악하기 위하여 준정량적 방법론을 적용, 해당 분야의 핵심기술을 도출함으로써 우선적으로 연구개발이 필요한 기술을 식별하여 향후 연구개발 추진시 기술별 우선순위를 제안하고자 한다. 이를 위한 핵융합 에너지 개발과 관련하여 핵융합의 과학적 원리, 주요국가의 DEMO 개발 동향 등을 파악한다. 다음으로 핵융합 실증로와 관련된 기술분류 체계를 검토하여 분석할 기술분류 체계를 선정한다. 선정된 기술체계에 준정량적 방법론으로 기술수준(TRL)을 파악하고 이를 보완하기 위하여 분석적 계층화 과정(AHP)을 적용한다. TRL과 AHP의 결과를 종합하여 우선적으로 확보해야 할 핵융합 실증로의 핵심기술은 실증로용 연소 플라즈마 기술, 대면재료기술, 구조재기술, 고주파 가열장치 기술, 중성입자빔 장치기술, 안전기술, 연소플라즈마 진단장치기술, 핵융합로 시뮬레이터기술 등으로 나타났다.