• Biomolecules & Therapeutics
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• 제25권5호
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• pp.511-518
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• 2017

Ultraviolet (UV) irradiation is a relevant environment factor to induce cellular senescence and photoaging. Both autophagy- and silent information regulator T1 (SIRT1)-dependent pathways are critical cellular processes of not only maintaining normal cellular functions, but also protecting cellular senescence in skin exposed to UV irradiation. In the present studies, we investigated whether modulation of autophagy induction using a novel synthetic SIRT1 activator, heptasodium hexacarboxymethyl dipeptide-12 (named as Aquatide), suppresses the UVB irradiation-induced skin aging. Treatment with Aquatide directly activates SIRT1 and stimulates autophagy induction in cultured human dermal fibroblasts. Next, we found that Aquatide-mediated activation of SIRT1 increases autophagy induction via deacetylation of forkhead box class O (FOXO) 1. Finally, UVB irradiation-induced cellular senescence measured by $SA-{\beta}-gal$ staining was significantly decreased in cells treated with Aquatide in parallel to occurring SIRT1 activation-dependent autophagy. Together, Aquatide modulates autophagy through SIRT1 activation, contributing to suppression of skin aging caused by UV irradiation.

• Journal of the Korean Vacuum Society
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• 제21권3호
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• pp.178-184
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• 2012

Carbon coils could be synthesized on nickel catalyst layer-deposited silicon oxide substrate using $C_2H_2$ and $H_2$ as source gases and $SF_6$ as an additive gas under thermal chemical vapor deposition system. The characteristics (formation density and morphology) of as-grown carbon coils were investigated as functions of additive gas flow rate and the cycling on/off modulation of $C_2H_2/SF_6$ flows. Even in the lowest $SF_6$ flow rate (5 sccm) in this work, the cycling on/off modulation injection of $SF_6$ flow for 2 minutes could give rise to the formation of nanosized carbon coils, whereas the continuous injection of $SF_6$ flow for 5 minutes could not give rise to the carbon coils formation. With increasing $SF_6$ flow rates from 5 to 30 sccm, the cycling on/off modulation injection of $SF_6$ flow confines the geometry for the carbon coils to the nanosized ones. Fluorine's role of $SF_6$ during the reaction was regarded as the main cause for the confinement of carbon coils geometries to the nano-sized ones.

• Development and Reproduction
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• 제15권3호
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• pp.249-256
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• 2011

Nesfatin-1/NUCB2, which is secreted from the brain, is known to control appetite and energy metabolism. Recent studies have been shown that nesfatin-1/NUCB2 was expressed not only in the brain, but it was also expressed in the gastric organs and adipose tissue. However, little is known about the expression of nesfatin-1/NUCB2 in the male reproductive system. Therefore, we examined whether the nesfatin-1/NUCB2 and its binding site exists in the male reproductive organs. Nesfatin-1/NUCB2 mRNA and protein were detected in the mouse testis and epididymis by PCR and Western blot analysis. As a result of the immunohistochemistry staining, the nesfatin-1 protein was localized at the interstitial cells and Leydig cells in the testis. Nesfatin-1 binding sites were also displayed at boundary cells in the tunica albuginea. Furthermore, in order to examine if the expression of nesfatin-1/NUCB2 mRNA in the testis and epididymis were affected by gonadotropin, its mRNA expression was analyzed after PMSG administration into mice. NUCB2 mRNA expression levels were increased in both of the testis and epididymis after PMSG administration. These results demonstrated for the first time that nesfatin-1 and its binding site were expressed in the mouse testis and epididymis. In addition, nesfatin-1/NUCB2 mRNA expression was controlled by gonadotropin, suggesting a possible role of nesfatin-1 in the male reproductive organs as a local regulator. Due to this, further study is needed to elucidate the functions of nesfatin-1 on the male reproductive system.

• Journal of Biosystems Engineering
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• 제9권1호
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• pp.22-33
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• 1984

Husk separator is an indispensable equipment in rice milling plants. However, any basic research on the designing and operating criteria of the husk separator have rarely been conducted in Korea. According to the survey results reported recently, grain loss occurs in the process of rice husk separation at custom rice milling plants in Korea and the performance of husk separator has also not been identified. With this regard this study was conducted with a typical commercial husk separator to investigate the effect of the operational factors such as feed rate, blower speed and opening ratio on the velocity distribution in the air duct and the performance of the separator. The results are summerized as follows: 1. The average wind velocity in the primary air duct increased linearly with the blower rpm and the size of air inlet port in both cases of double type and single type operations. 2. The coefficient of variation in the horizontal wind velocities in the primary air duct was the minimum when the opening ratio was 0.22 ($0.052m^2$ of air inlet port) in both cases of single type and double type operations regardless of the blower speeds used in this test. The average wind velocity at the upper part of air duct was greater by 2-5 m/s than the velocity at the bottom part in double type operation. In case of single type operation, however, the average velocity in the middle part was greater than the upper or bottom part when the opening ratio was greater than 0.74. 3. The relationship between the overall effectiveness of separation(Ed for double type and Es for single type) and the average wind velocity (Va) in the primary air duct was expressed in the following quadratic functions. $$Ed=-190.84+106.18Va-10.052Va^2$$ ($r^2$ = 0.97782) $$Es=-223.76+106.23Va-9.1935Va^2$$ ($r^2$ = 0.97029) The average wind velocity required to obtain the overall effectiveness of separation more than 80% ranged from 4.04 m/sec to 5.84 m/sec in case of double type operation, and from 4.70 m/sec to 6.20 m/sec in case of single type. 4. An optimum wind velocity can be obtained with an increase in the blower speed or the size of air inlet port as presented in Figure 8. There was a tendency that the faster the blower speed, the narrower the control range of the air inlet port. 5. The feed rates (1850kg/hr and 2100kg/hr) adopted in this experiment did not bring about a significant difference in both the overall effectiveness of separation and the power consumption. 6. The energy consumption increased cubically with the blower speed but linearly with the size of the air inlet port. On the basis of the results described in items 1, 3, and 6, it would be more economic to adjust the size of the air inlet port larger with a relatively low blower speed than to adjust the size smaller with a relatively high speed.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제18권7호
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• pp.688-698
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• 2017

This study was conducted to identify the conceptual definitions and attributes of fatigue in hemodialysis patients based on the Hybrid Model of concept development. The Hybrid Model was used to investigate the main attributes and indicators of the concept by applying three stages. After a literature review, data were collected through observation and interviews including qualitative research in the field work stage. The participants included 10 patients in hemodialysis center of two hospitals in Gwang-ju, Korea. The attributes of fatigue concept in the hemodialysis patients were divided into four dimensions, physical activity, affective mood, social role, and cognitive reflection. The definition of fatigue by hemodialysis patients was defined as 'subjective feeling usually experienced in four dimensions during the process to recognize and adjust energy deficiency and limited functions caused by uremia and repeated hemodialysis for chronic renal failure'. Considering the dimensions and attributes derived from this study, it may be possible to develop an effective intervention program for fatigue in hemodialysis patients.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제21권5호
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• pp.47-53
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• 2020

The purpose of this study was to increase product reliability by improving the durability of the breech block for a 30mm Automatic Gun. The breech block is a key component of a gun that functions as chambering, closing, and extracting. The breech block requires high reliability, which needs to be improved because cracks of a breech block can occur early in operation. Cause analysis confirmed that the crack is caused by repeated impacts. Therefore, the following improvement measures were studied, and the effects were demonstrated using a firing test. The energy of impact absorption was increased by changing the material, and the stress concentration was mitigated by increasing the value of R. In addition, the fatigue life was increased by adding Shot-peening, deleting chromium plating, and changing the forging method. The firing test did not show firing trouble for up to 5,000 rounds. The start timing of the crack was delayed, and the depth was small. Therefore, the improved product was more durable than the existing product. This study can be used as a useful reference when assessing the improvement of the durability of similar products, life study, and criteria for crack acceptance.

• Journal of Microbiology and Biotechnology
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• 제16권6호
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• pp.901-910
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• 2006

Poly(3-hydroxybutyrate) [P(3HB)] is a microbial polyester intracellularly accumulated as distinct granules in numerous microorganisms as an energy and carbon storage material. Recombinant Escherichia coli harboring the heterologous P(3HB) biosynthesis genes accumulates large amounts of P(3HB) granules, yet the granule-associated proteins have not been identified. Therefore, this study reports on an analysis of the P(3HB) granule-associated proteome in recombinant E. coli. Fiye proteins out of 7 spots identified were found to be involved in functions of translation, heat-stress responses, and P(3HB) biosynthesis. Two of the major granule-associated proteins, IbpA/B, which are already known to bind to recombinant proteins forming inclusion bodies in E. coli, were further analyzed. Immunoblotting and immunoelectron microscopic studies with IbpA/B antibodies clearly demonstrated the binding and localization of IbpA/B to P(3HB) granules. IbpA/B seemed to play an important role in recombinant E. coli producing P(3HB) by stabilizing the interface between the hydrophobic P(3HB) granules and the hydrophilic cytoplasm. Thus, IbpA/B were found to act like phasins in recombinant E. coli, as they are the major proteins bound to the P(3HB) granules, affect the morphology of the granules, and reduce the amount of cytosolic proteins bound to the P(3HB) granules.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제21권8호
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• pp.417-428
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• 2020

Housekeeping genes are expressed in cells of all organisms and perform basic cellular functions such as energy generation, substance synthesis, cell death, and cell defense. Accordingly, the expression levels of housekeeping genes are relatively constant, and thus they are used as reference genes in gene expression studies, such as protein expression and mRNA expression analysis of target genes. However, the levels of expression of these genes may be different among various tissues or cells and may change under certain circumstances. Therefore, it is important to select the best reference gene for specific gene expression research by exploring the stability of housekeeping gene expression. This review summarizes housekeeping genes found in humans, chickens, pigs, and rats in the literature and estimates expression stability using geNorm, NormFinder, and BestKeeper software. The most suitable reference housekeeping gene can selected based on expression stability according to the experimental conditions of the gene expression study and can thus be applied to data normalization.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제17권7호
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• pp.704-712
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• 2016

Recently, the installation of photovoltaic (PV) systems has been increasing due to the worldwide interest in eco-friendly and infinitely abundant solar energy. However, the output power of PV systems is highly influenced by the surrounding environment. For instance, a string of PV systems composed of modules in series may become inoperable under cloudy conditions or when in the shade of a building. In other words, under these conditions, the existing control method of PV systems does not allow the string to be operated in the normal way, because its output voltage is lower than the operating range of the grid connected inverter. In order to overcome this problem, we propose a new control method using a DC-DC voltage regulator which can compensate for the voltage of each string in the PV system. Also, based on the PSIM S/W, we model the DC-DC voltage regulator with constant voltage control & MPPT (Maximum Power Point Tracking) control functions and 3-Phase grid connected inverter with PLL (Phase-Locked Loop) control function. From the simulation results, it is confirmed that the present control method can improve the operating efficiency of PV systems by compensating for the fluctuation of the voltage of the strings caused by the surrounding conditions.

• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.152-161
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• 2015

CodY is a highly conserved protein in low G+C gram-positive bacteria that regulates genes involved in sporulation and stationary-phase adaptation. Bacillus thuringiensis is a grampositive bacterium that forms spores and parasporal crystals during the stationary phase. To our knowledge, the regulatory mechanism of CodY in B. thuringiensis is unknown. To study the function of CodY protein in B. thuringiensis, BMB171codY^- was constructed in a BMB171 strain. A shuttle vector containing the ORF of cry1Ac10 was transformed into BMB171 and BMB171codY^-, named BMB171cry1Ac and BMB171codY^-cry1Ac, respectively. Some morphological and physiological changes of codY mutant BMB171codY^-cry1Ac were observed. A comparative proteomic analysis was conducted for both BMB171codY^-cry1Ac and BMB171cry1Ac through two-dimensional gel electrophoresis and MALDI-TOF-MS/MS analysis. The results showed that the proteins regulated by CodY are involved in microbial metabolism, including branched-chain amino acid metabolism, carbohydrate metabolism, fatty acid metabolism, and energy metabolism. Furthermore, we found CodY to be involved in sporulation, biosynthesis of poly-β-hydroxybutyrate, growth, genetic competence, and translation. According to the analysis of differentially expressed proteins, and physiological characterization of the codY mutant, we performed bacterial one-hybrid and electrophoretic mobility shift assay experiments and confirmed the direct regulation of genes by CodY, specifically those involved in metabolism of branched-chain amino acids, ribosomal recycling factor FRR, and the late competence protein ComER. Our data establish the foundation for in-depth study of the regulation of CodY in B. thuringiensis, and also offer a potential biocatalyst for functions of CodY in other bacteria.