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81.
Hye Jin Hwang Sang Woo Kim Yu Mi Baek Sung Hak Lee Hee Sun Hwang Jong Won Yun 《Korean Journal of Chemical Engineering》2009,26(1):115-126
We established the gene expression profiling in streptozotocin (STZ)-induced diabetic rat liver in response to hypoglycemic
fungal polysaccharides (EPS), using oligonucleotide microarray analysis. Differentially regulated genes showing higher fold
change than 2 were identified and categorized through hierarchical clustering analysis. Among the 835 genes analyzed, 244
were up-regulated, while 321 were down-regulated after diabetes induction. Interestingly, many gene expressions altered after
STZ-treatment mimicked a normal rat liver by EPS therapy. Most of these genes included genes involving cell structure and
motility, immunity and defense, lipid, fatty acid and steroid metabolism, protein metabolism and modification, and signal
transduction. More importantly, we found a total of 36 genes that showed significant fold changes in their expression that
have not previously been examined in the context of diabetes. To validate the microarray results, we further confirmed the
gene expression patterns by RT-PCR using four genes of interest (carboxylesterase 2, stearoyl-coenzyme A desaturase 1, insulin-like
growth factor 1, and insulin-like growth factor binding protein 2). Taken together, EPS acted as a potent regulator of gene
expression for a wide variety of genes in diabetic rat liver. 相似文献
82.
Eunyoung Lee Michelle Novais de Paula Sangki Baek Huynh Kim Khanh Ta Minh Tan Nguyen Taeck-Hyun Jeong Chong Jai Kim Yeon Jin Jang Han Choe 《International journal of molecular sciences》2021,22(12)
Human stem-cell factor (hSCF) stimulates the survival, proliferation, and differentiation of hematopoietic cells by binding to the c-Kit receptor. Various applications of hSCF require the efficient and reliable production of hSCF. hSCF exists in three forms: as two membrane-spanning proteins hSCF248 and hSCF229 and truncated soluble N-terminal protein hSCF164. hSCF164 is known to be insoluble when expressed in Escherichia coli cytoplasm, requiring a complex refolding procedure. The activity of hSCF248 has never been studied. Here, we investigated novel production methods for recombinant hSCF164 and hSCF248 without the refolding process. To increase the solubility of hSCF164, maltose-binding protein (MBP) and protein disulfide isomerase b’a’ domain (PDIb’a’) tags were attached to the N-terminus of hSCF164. These fusion proteins were overexpressed in soluble form in the Origami 2(DE3) E. coli strain. These solubilization effects were enhanced at a low temperature. His-hSCF248, the poly-His tagged form of hSCF248, was expressed in a highly soluble form without a solubilization tag protein, which was unexpected because His-hSCF248 contains a transmembrane domain. hSCF164 was purified using affinity and ion-exchange chromatography, and His-hSCF248 was purified by ion-exchange and gel filtration chromatography. The purified proteins stimulated the proliferation of TF-1 cells. Interestingly, the EC50 value of His-hSCF248 was 1 pg/mL, 100-fold lower than 9 ng/mL hSCF164. Additionally, His-hSCF248 decreased the doubling time, increased the proportion of S and G2/M stages in the cell cycle, and increased the c-Myc expression at a 1000-fold lower concentration than hSCF164. In conclusion, His-hSCF248 was expressed in a soluble form in E. coli and had stronger activity than hSCF164. The molecular chaperone, MBP, enabled the soluble overexpression of hSCF164. 相似文献
83.
Sung-Chan Kim Baek-Seok Ko Tae-Jong Baek Byeong-Ok Lim An D. Dong-Hoon Shin Jin-Koo Rhee 《Microwave and Wireless Components Letters, IEEE》2005,15(10):652-654
The hybrid ring coupler was designed and fabricated on a GaAs substrate using surface micromachining techniques, which adopted dielectric-supported air-gapped microstrip line (DAML) structure. The fabrication process of DAML is compatible with the standard monolithic microwave integrated circuit (MMIC) techniques, and the hybrid ring coupler can be simply integrated into a plane-structural MMIC. The fabricated hybrid ring coupler shows wideband characteristics of the coupling loss of 3.57 /spl plusmn/ 0.22dB and the transmission loss of 3.80 /spl plusmn/ 0.08dB across the measured frequency range of 85 to 105GHz. The isolation characteristics and output phase differences are -34dB and 180/spl plusmn/1/spl deg/, at 94GHz, respectively. 相似文献
84.
Jeom-In Baek Chong Kul Ryu Tae Hyoung Eom Joong Beom Lee Won-Sik Jeon Jongheop Yi 《Korean Journal of Chemical Engineering》2011,28(11):2211-2217
Chemical-looping combustion (CLC) of syngas has a potential to generate power economically with achieving the inherent carbon
dioxide capture. An oxygen carrier with high reactivity and excellent physical properties would make CLC technology more competitive.
In this work, oxygen carrier with 70 wt% NiO was prepared by spray drying technique. The prepared oxygen carrier had excellent
physical properties for fluidized-bed application of CLC process. The reactivity of the oxygen carrier in repeated reduction-oxidation
was measured by thermogravimetric analyzer with simulated syngas. Oxygen carrier calcined at 1,100 °C showed high oxygen transfer
capacity of 14.7 wt%, utilizing 98% of the transferable oxygen. Oxygen transfer capacity and oxygen transfer rate was increased
with the increase of reaction temperature, and the highest oxygen transfer rate was observed when about half of the transferable
oxygen reacted with syngas. The reduction rate of the syngas (mixture of H2 and CO) appeared to be approximately the sum of the reaction rate of each fuel gas. The experimental results indicated that
the spray-dried NiO oxygen carrier prepared in this work could be a good quality oxygen carrier for the CLC of syngas. 相似文献
85.
Digital games appear to motivate players intrinsically. Of various game features, fantasy in particularly plays a crucial role in enhancing motivation and is a key factor in immersion in gameplay. As with its inherent value, fantasy also plays a vital role in distinguishing digital games itself from other media. Despite its significance, fantasy has received little attention, and this concept is still ambiguous to define with any certainty. This study thus aims to create a framework to explore a dimension of fantasy and to develop a scale to measure a state of fantasy in digital games. As a result, four factors were extracted, which were ‘identification’, ‘imagination’, ‘analogy’, and ‘satisfaction’, to account for fantasy state in digital gameplay. Based on these factors, a fantasy scale in digital games (FSDGs) included 16 items was developed. 相似文献
86.
An integral equation model for critical heat flux at subcooled and low quality flow boiling 总被引:1,自引:0,他引:1
A new theoretical model of critical heat flux (CHF) is developed for the flow boiling condition from bubble-detached to low quality range. The CHF condition is postulated to occur when the superheated liquid layer on the heated wall, which is formed under the bubbly layer from the point of the onset of significant void generation, is depleted due to the evaporation along the heated length. The model shows a very promising agreement with the uniformly heated round tube data for both water and refrigerants by simply applying well-known constitutive relationships without any tuning constant for the CHF data. The significance of the proposed model in unifying the existing models is also discussed. 相似文献
87.
Eun Gyo Lee Seung Hui Lee Kyung Mi Park Jung Eun Baek Sun Hee Yeon Jin‐Ki Park Won‐Kyong Chang Joon‐Ki Jung Bong Hyun Chung 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(5):643-649
BACKGROUND: Human erythropoietin (hEPO), a hydrophobic acidic glycoprotein responsible for the regulation of red blood cell production in mammals, is used for the treatment of anemia. In general, the purification of transgenic animal‐derived therapeutic proteins is not easy due to their low titer concentrations and abundant contaminant proteins. For the first time, here the purification and characterization of rhEPO from the milk of transgenic pigs are described. RESULTS: The rhEPO was purified by heparin chromatography, reverse‐phase chromatography, and gel filtration chromatography, resulting in a 16.5% yield and > 98% purity. The rhEPO purified from the milk of transgenic pigs contained less acidic isoforms and was underglycosylated in contrast to CHO‐derived rhEPO. Cell proliferation of the F‐36/EPO‐dependent cell line was proportional to the dose of transgenic pig‐derived rhEPO. CONCLUSION: Transgenic pig‐derived rhEPO with high purity was achieved after three‐step chromatography following two‐step precipitation. The transgenic pig‐derived rhEPO was demonstrated to have comparable potency with CHO‐derived rhEPO. Transgenic pig‐derived rhEPO may not be therapeutically feasible because of different glycosylation, and thus further studies are required to elucidate the effect of this aberrant glycosylation on the biological activity and stability in vivo. Copyright © 2008 Society of Chemical Industry 相似文献
88.
Myung-Sun Kim Kyunggon Kim Su Kyung Oh Gidae Lee Jin-Ock Kim Lan Li Jung-Hyun Park Kwang-Hyun Baek 《International journal of molecular sciences》2021,22(12)
To increase the half-life of growth hormones, we proposed its long-lasting regulation through the ubiquitin-proteasome system (UPS). We identified lysine residues (K67, K141, and K166) that are involved in the ubiquitination of human growth hormone (hGH) using ubiquitination site prediction programs to validate the ubiquitination sites, and then substituted these lysine residues with arginine residues. We identified the most effective substituent (K141R) to prevent ubiquitination and named it AUT-hGH. hGH was expressed and purified in the form of hGH-His, and ubiquitination was first verified at sites containing K141 in the blood stream. Through the study, we propose that AUT-hGH with an increased half-life could be used as a long-lasting hGH in the blood stream. 相似文献
89.
Junggeun Jhin Jong Hyeob Baek Dongjin Byun 《Journal of the Society for Information Display》2008,16(4):535-539
Abstract— The structural, electrical, and optical properties of GaN epilayers grown on various ion‐implanted sapphire(0001) substrates by MOCVD were investigated. GaN or AlN buffer layers and pre‐treatment were indispensably introduced before GaN‐epilayer growth. The ion‐implanted substrate's surface had decreased internal free energies during the growth of the ion‐implanted sapphire(0001) substrates. The crystal and optical properties of the GaN epilayers grown in ion‐implanted sapphire(0001) substrates were improved. Also, an excessively roughened and modified surface caused by ions degraded the GaN epilayers. Not only the ionic radius but also the chemical species of implanted sapphire(0001) substrates improved the properties of the GaN epilayers grown by MOCVD. It is obvious that the ion‐implanted pre‐treatment of sapphire(0001) substrates can be an alternative pre‐treatment procedure for GaN deposition and has the potential to improve the properties of the GaN epilayers on sapphire(0001) substrates. 相似文献
90.
Yong Che Kim Huhn Jun Kim Chang Hee Lee Baek Seok Seong Soon-Chul Kim 《Metals and Materials International》1998,4(6):1101-1109
Textures of metallic uranium rods were measured by neutron diffraction. From experimentally measured single and composite
pole figures, the crystallite orientation distribution function (ODF) was determined by the harmonic method using a computer
program developed for the fiber texture with orthorhombic crystal symmetry. The composite pole figures measured at overlapped
peak positions of the diffraction pattern were assumed to be a linear combination of several neighboring single pole figures.
The calculated results show that the harmonic method based on this conjecture well recovers the experimentally measured composite
pole figures. Anisotropie physical properties such as thermal expansion coefficients and elastic constants due to the texture
were evaluated by numerically averaging the second and fourth rank tensors with the calculated ODF, respectively. 相似文献