• Environmental Engineering Research
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• 제13권4호
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• pp.171-176
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• 2008

Studies on visible-light-driven photocatalysis of air pollutants at indoor air quality (IAQ) levels have been limited. Current study investigated visible-light derived photocatalysis with N-doped and S-doped titanium dioxide ($TiO_2$) for the control of benzene at indoor levels. Two preparation processes were employed for each of the two types of photocatalyst: urea-Degussa P-25 $TiO_2$ and titania-colloid methods for the N-doped $TiO_2$; and titanium isopropoxid- and tetraisopropoxide-thiourea methods for the S-doped $TiO_2$. Furthermore, two coating methods (EDTA- and acetylacetone-dissolving methods) were tested for both the N-doped and S-doped $TiO_2$. The two coating methods exhibited different photocatalytic degradation efficiency for the N-doped photocatalysts, whereas they did not exhibit any difference for the S-doped photocatalysts. In addition, the two doping processes showed different photocatalytic degradation efficiency for both the S-doped and N-doped photocatalysts. For both the N-doped and S-doped $TiO_2$, the photocatalytic oxidation (PCO) efficiency increased as the hydraulic diameter (HD) decreased. The degradation efficiency determined via a PCO system with visible-light induced $TiO_2$ was lower than that with UV-light induced unmodified $TiO_2$, which was obtained from previous studies. Nevertheless, it is noteworthy that for the photocatalytic annular reactor with the HD of 0.5 cm, PCO efficiency increased up to 52% for the N-doped $TiO_2$ and 60% for the S-doped $TiO_2$. Consequently, when combined with the advantage of visible light use over UV light use, it is suggested that with appropriate HD conditions, the visible-light-assisted photocatalytic systems can also become an important tool for improving IAQ.

• Asian-Australasian Journal of Animal Sciences
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• 제31권8호
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• pp.1345-1357
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• 2018

Objective: This study examined the influence of dietary supplementation of Nigella sativa seeds, Rosmarinus officinalis leaves and their combination on carcass attributes, fatty acid (FA) composition, gene expression, lipid oxidation and physicochemical properties of longissimus dorsi (LD), semitendinosus (ST), and supraspinatus (SS) muscles in Dorper lambs. Methods: Twenty-four Dorper lambs ($18.68{\pm}0.6kg$, 4 to 5 months old) were randomly assigned to a concentrate mixture containing either, no supplement (control, T1), 1% Rosmarinus officinalis leaves (T2), 1% Nigella sativa seeds (T3), or 1% Rosmarinus officinalis leaves+1% Nigella sativa seeds (T4) on a dry matter basis. The lambs were fed the treatments with urea-treated rice straw for 90 days, slaughtered and the muscles were subjected to a 7 d postmortem chill storage. Results: The T2 lambs had greater (p<0.05) slaughter and cold carcass weights than the control lambs. Dietary supplements did not affect (p>0.05) chill loss, dressing percentage, carcass composition, intramuscular fat and muscle pH in Dorper lambs. Meat from supplemented lambs had lower (p<0.05) cooking and drip losses, shear force, lightness, and lipid oxidation and greater (p<0.05) redness compared with the control meat. The impact of dietary supplements on muscle FA varied with muscle type. Diet had no effect (p>0.05) on the expression of stearoyl-CoA desaturase and lipoprotein lipase genes in LD and ST muscles in Dorper lambs. The T2 and T3 diets up regulated the expression of AMP-activated protein kinase alpha 2 gene in LD and ST muscles and up regulated the expression of sterol regulatory element-binding protein 1 in ST muscle in Dorper lambs. Conclusion: Dietary supplementation of Nigella sativa seeds and Rosmarinus officinalis leaves had beneficial effects on meat quality in Dorper lambs.

• BMB Reports
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• 제32권5호
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• pp.486-491
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• 1999

An engineered cDNA from Phanerochaete chrysosporium encoding both the mature and propeptide-sequence regions of lignin peroxidase H2 (Lip H2) was overexpressed in Escherichia coli BL21 (DE3) to evaluate its catalytic characteristics and potential application as a pollution scavenger. All expressed proteins were aggregated in an inactive inclusion body, which might be due to inherent disulfide bonds. Active enzyme was obtained by refolding with glutathione-mediated oxidation in refolding solution containing $Ca^{2+}$, heme, and urea. Propeptide-sequence region was not processed as evidenced by N-terminal sequence analysis. Recombinant Lip H2 (rLip H2) had the same physical properties of the native protein but differed in the $K_{cat}$. Catalytic efficiency ($k_{cat}/K_m$) of rLip H2 was slightly higher than that of the native enzyme. In order to express an active protein, fusion systems with thioredoxin or Dsb A, which have disulfide isomerase activity, were used. The fused proteins expressed by the Dsb A fusion vector were aggregated, whereas half of the thioredoxin fusion proteins were recovered as a soluble form but still catalytically inactive. These results suggest that Lip H2 may not be expressed as an active enzyme in Escherichia coli although the activity can be recovered by in vitro refolding.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.738-744
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• 2003

The gene ADH encoding NAD-dependent alcohol dehydrogenase from Bacillus stearothennophilus was cloned and overexpressed as a GST fusion protein at a high level in Escherichia coli. The expressed fusion protein was purified simply by glutathione affinity chromatography. GST fusion protein was then cleaved by thrombin, while soluble enzyme was further purified by glutathione affinity chromatography. The recombinant enzyme had the same elctrophoretic mobility as the native enzyme from Bacillus stearothennophilus. The recombinant enzyme catalyzed the oxidation of a number of alcohols and exhibited high activities towards secondary alcohols. The $K_m\;and\;V_{max}$ values of the recombinant enzyme for ethanol were 5.11 mM and 61.35 U/mg, respectively. Pyridine and imidazole notably inhibited the enzymatic activity. The activity of the recombinant enzyme optimally proceeded at pH 9.0 and $70^{\circ}C$. The midpoint of the temperature-stability curve for the recombinant enzyme was approximately $68^{\circ}C$, and the enzyme was not completely inactivated even at $85^{\circ}C$. The recombinant enzyme showed a high resistance towards denaturing agents (0.05% SDS, 0.1 M urea). Therefore, due to its stability and relatively broad substrate specificity, the recombinant enzyme could be utilized in bio-industrial processes and biosensors.

• 대한유전성대사질환학회지
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• 제16권3호
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• pp.123-134
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• 2016

Mitochondrial disease is a group of disorders caused by dysfunctional mitochondria, the organelles that generate energy for the cell. Diagnosis of mitochondrial disease is difficult, subtle, and has many problems. It is more likely to miss the diagnosis of mitochondrial disease, especially in borderline cases where the symptoms of the disease are not severe. In this regard, urine organic acid analysis is noninvasive and can increase the sensitivity and specificity through repeated load test with few changes according to the specimen. And, It is considered to be suitable as a screening test for mitochondrial diseases because it has a great advantage of distinguishing from organic aciduria, urea cycle disorder and fatty acid oxidation disorder which may have similar symptoms. The purpose of this study was to investigate the clinical features and age distribution of mitochondrial diseases diagnosed by organic acid analysis and to establish the policy of diagnosis and treatment based on this study.

• Applied Biological Chemistry
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• 제41권1호
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• pp.60-66
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• 1998

10종의 식용 버섯 자실체에 대한 항보체 활성 검색에서 가장 높은 활성을 나타낸 양송이버섯 자실체를 대상으로 항보체 활성물질의 추출조건을 조사하였다. 최적조건으로서 5% urea가 함유된 0.1 N NaOH 용액으로 $65^{\circ}C$에서 2시간동안 양송이버섯 자실체를 추출한 후 methanol 가용획분이 제거된 조다당 획분 AB-0를 얻었다. AB-0는 1 mg/ml에서 90% 이상의 높은 항보체활성을 나타내었으며 마우스에 이식된 sarcoma-180에 대하여 74%의 저지효과를 보였다. AB-0를 acetone 농도에 따른 침전 분획을 실시하여 AB-20, AB-40, AB-60, AB-80, AB-A의 5개의 획분을 얻었다. 이중 가장 높은 항보체활성과 수율을 나타낸 AB-20 획분은 탄수화물 39%, 단백질 46%를 함유하였으며, 구성당은 glucose, arabinose, xylose, galactose, mannose가 6.49 : 1.98 : 1.24 : 1.00 : 0.71의 비율로 존재하였고 구성아미노산은 isoleucine(12.60%), glutamic acid+glutamine(12.45%), valine(11.79%), alanine(11.46%), leucine(10.19%)와 aspartic acid, asparagine(10.56%) 등 이었다. Pronase 처리한 AB-20에서는 78.5%의 항보체활성을 나타내고 대조군에 비해 14.5% 감소하였으나, AB-20의 periodate 산화물에서는 활성이 42.6%로 50% 이상 크게 감소하였다. 따라서 양송이 버섯의 알칼리 추출물중 가장 강한 활성을 보인 AB-20의 주요 활성부위는 다당류이며 단백질도 일부 관여하는 것으로 생각되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권6호
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• pp.871-884
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• 2009

Gene expression profiling is a useful tool for identifying critical genes and pathways in metabolism. The objective of this study was to determine the major differences in the expression of genes associated with metabolism and metabolic regulation in liver and mammary tissues of lactating cows. We used the Michigan State University bovine metabolism (BMET) microarray; previously, we have designed a bovine metabolism-focused microarray containing known genes of metabolic interest using publicly available genomic internet database resources. This is a high-density array of 70mer oligonucleotides representing 2,349 bovine genes. The expression of 922 genes was different at p<0.05, and 398 genes (17%) were differentially expressed by two-fold or more with 222 higher in liver and 176 higher in mammary tissue. Gene ontology categories with a high percentage of genes more highly expressed in liver than mammary tissues included carbohydrate metabolism (glycolysis, glucoenogenesis, propanoate metabolism, butanoate metabolism, electron carrier and donor activity), lipid metabolism (fatty acid oxidation, chylomicron/lipid transport, bile acid metabolism, cholesterol metabolism, steroid metabolism, ketone body formation), and amino acid/nitrogen metabolism (amino acid biosynthetic process, amino acid catabolic process, urea cycle, and glutathione metabolic process). Categories with more genes highly expressed in mammary than liver tissue included amino acid and sugar transporters and MAPK, Wnt, and JAK-STAT signaling pathways. Real-time PCR analysis showed consistent results with those of microarray analysis for all 12 genes tested. In conclusion, microarray analyses clearly identified differential gene expression profiles between hepatic and mammary tissues that are consistent with the differences in metabolism of these two tissues. This study enables understanding of the molecular basis of metabolic adaptation of the liver and mammary gland during lactation in bovine species.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.85-90
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• 2010

As the environmental regulation of vehicle emission is strengthened, investigations for $NO_x$ and PM reduction strategies are popularly conducted. Two current available technologies for continuous $NO_x$ reduction onboard diesel vehicles are Selective Catalytic Reduction (SCR) using aqueous urea and lean $NO_x$ trap (LNT) catalysts. The experiments were conducted to investigate the $NO_x$ reduction performance of SCR system which can control the ratio of $NO/NO_2$, temperature and SV(space velocity), and the model gas was used which is similar to a diesel exhaust gas. The maximum reduction efficiency is indicated when the $NO:NO_2$ ratio is 1:1 and the SV is 30,000 $h^{-1}$ in $300^{\circ}C$. Generally, ammonia slip from SCR reactors are rooted to incomplete conversion of $NH_3$ over the SCR. In this research, slip was occurred in 6cases (except low SV and $NO:NO_2$ ratio is 1:1) after SCR. Among 6 case of slip occurrence, the maximum conversion efficiency is observed when SV is 60,000 $h^{-1}$ in $400^{\circ}C$.

• KSBB Journal
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• 제11권4호
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• pp.462-469
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• 1996

미생물을 이용한 석탄의 액화 연구를 통하여 몇가지 중요한 결론을 얻을 수 있었다. 호주산 갈탄의 효과적인 전처리제로는 HNOJ가 선정되었으며, S. viridosporus와 P. cocos의 최적 초기 pH는 각각 7.5와 4.5로 나타났으며, S. viridosporus가 초기액화 속도 및 전체 액화능에서 P. cocos 보다 우수한 액화능을 보였다. 액화능을 높이기 위한 첨가제로서는 S S. viridosporus는 요소가 효과적 이었고, p. cocos는 랩톤과 트립톤이 효과척으로 나타났다. 최고 액화능은 회분식 교반기 조업에서 S. viridosporus에서 85 % % (w/w)까지 향상시킬 수가 있었다. 액화 기간은 3.5 일까지 단축할 수가 있었다. 분광학적 분석 결과 및 각 단계별로 석탄의 성분을 분석한 결과에서 미생물에 의한 석탄의 액화는 석탄의 계속적 인 산화현 상에 기인함을 밝혔다. 또한, S. viridosporus에 의한 액화의 기작은 미생물의 외분비 물질에 의하여 진행되며, 액화 가작중 80 %는 이차대사생성물에 의한 비효소반응이였으며, 20%는 효소반응으로 나타났다.

• 한국가스학회지
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• 제15권2호
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• pp.21-26
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• 2011

대형경유차는 수량이 적음에도 불구하고 높은 운행 빈도로 인해 대기오염물질의 높은 비율을 차지하고 있다. 이에 대한 해결책으로 저공해 자동차인CNG(CompressedNatural Gas)버스가 대두되고 있다. CNG차량의 배출가스는 경유에 비해 PM이나 NOx가 크게 감소되는 경향을 보인다. 본 연구에서는 친환경 연료인 CNG에 수소를 혼합한 연료를 이용한 차량에서의 배기가스 후처리 기술에 대해 소개한다. CNG에 수소를 혼합함으로써, 엔진의 연소 효율은 올리고 배기가스를 감소시킬 수 있으나, CNG의 주성분인 메탄 역시 온실가스로서 이에 대한 저감도 필요한 실정이다. CNG엔진에서 배출되는 메탄에 대해 CNG산화촉매를 도입하여 저감 방향을 설정하였으며, 발생하는 NOx에 대해서는 urea-SCR 및HC(HydroCarbon)-SCR을 도입하였다.