• Ocean and Polar Research
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• v.35 no.4
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• pp.323-349
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• 2013

The mud shrimp Upogebia major (Upogebiidae: Decapoda: Crustacea) is a common species on muddy and sandy mud tidal flats in the west coast of Korea. They reside in Y-shaped burrows that can extend up to more than 2 meters below the sediment surface. They feed on suspended detritus carried into their burrow by the beating of their pleopods and captured by their hairy first two pairs of thoracic legs. Mud shrimp burrows provide a habitat for a variety of small organisms such as crabs, shrimps, polychaetes, and mollusks. Ovigerous females are observed from December to May. Females deposit eggs only once per breeding season. They start hatching in March and the pelagic larvae of first zoea appear in March and April, followed by benthic settlement in May. Growth over the first year is rapid, and females deposit their first eggs in the third breeding season, 31 months after their settlement. Adult shrimps live for 4~5 years. Depth of the burrow increases with body length. The deep burrows provide refuge from predators and physical stress, allowing the shrimps to survive for a long time. The mud shrimps supply oxygen-rich water to their deep burrows, and exert a great influence on the structure and metabolism of the tidal flat benthic community. However, recently this type of mud shrimp has posed a serious threat to the Korean clam industry along the west coast of Korea. The extensive burrowing shrimp populations suddenly invaded the tidal flats from 2010 where the clams (Ruditapes philippinarum) are raised. As a consequence, clam production has decreased by about 10% over the past three years in some Korean clam beds. Therefore, the objective of this study is to review the biology of this mud shrimp in order to seek solutions to control the burrowing of these shrimps.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.6 s.336
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• pp.17-22
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• 2005

Organic-inorganic hybrid type thin films are the next generation candidates as low-k materials. SiOC films are analyzed the bonding structure by the red and blue chemical shift using the fourier transform infraredspectra. Conventional chemical shift of organic chemistry is a red shift, but hybrid type SiOC films were observed the red and blue shift. The chemical shift originates from the interaction between the C-H bond and high electronegative atoms, and the blue shift in SiOC films is caused by the porosity due to the increase of the electron rich group such as much methyl radicals. The bonding structures of SiOC films are also divided into the Si-O-C cross-link structure and the Si-O-C cage-link structure due to the chemical shifts. The Si-O-C cross-link structure progressed the adhesion attributed to the C-H bond elongation in the reason of the red shift, and the dielectric constant also decreases.

• ALGAE
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• v.35 no.2
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• pp.189-200
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• 2020

Pyropia yezoensis has been used as functional food in East Asia, especially in Korea and Japan, for more than five hundred years. This study aims to evaluate the antioxidant effect of polyphenols and proteins-rich extracts from P. yezoensis (PPPs) against 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative cell damage. Among six Korean local strains obtained from Jinhae (JiH), Haenam (HN), Jangheung (JaH), Jindo (JD), Wando (WD), and Sinan (SA) areas, the extracts of P. yezoensis from SA and JD are relatively higher in polyphenols and proteins contents. SA showed the lowest IC₅₀ scavenging activities against 1,1-diphenyl-2-picryl-hydrazyl and alkyl radicals and displayed protective effects against reactive oxygen species (ROS) in AAPH-induced Vero cells. Especially, the PPPs extracts from SA and JD showed protective activities against AAPH-induced apoptosis, as observed by nuclear staining with Hoechst 33342. Furthermore, in vivo studies of the SA extract in zebrafish showed significantly reduced ROS generation, lipid peroxidation, and cell damage. This is the first study, to our knowledge, to evaluate the antioxidant bioactivity of PPP in the Korean Peninsula using a zebrafish model. Due to SA and JD both located in the west coast of Korea, we deduced that the chemical content of the different PPP extracts was mildly influenced by their geographic location, and this alga has potential of protective activity against AAPH-induced ROS both in vitro and in vivo.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1556-1571
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• 1993

Nitrogen oxides ($NO_x$) are air pollutants which are generated from the combustion of fossil fuels. Stage combustion is an effective method to reduce $NO_x$ emissions. The effects of $NO_x$ reduction by stage combustion in a pilot scale combustor(6.6kW) have been investigated using propane gas flames laden with NH$_{3}$ as Fuel-N. The results in this study are follows; (1) $NO_x$ emissions are dependent on the reducing environment of fuel-rich zone regardless of total air ratio. The maximum $NO_x$ reduction is at the stoichiometric ratio of 0.8 to 0.9 in the reducing zone. (2) $NO_x$ reduction is maximum when burnout air is injected at the point where the oxygen in reducing zone is almost consumed. (3) $NO_x$ reduction is dependent upon the temperature of reducing zone with best effect above 950.deg. C in the reducing zone. (4) The fuel stage combustion is more effective to reduce $NO_x$ formation in the wide range of stoichiometric ratio than two stage combustion. (5) The results of this study could be utilized mainly in a design strategy for low $NO_x$ emission from the combustion of high fuel-nitrogen in energy sources ratio than as an indication of the absolute levels of $NO_x$ which can be achieved by stage combustion techniques in large scale facilities.

• The Plant Pathology Journal
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• v.36 no.1
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• pp.43-53
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• 2020

Ralstonia solanacearum (Rso) is a causal agent of bacterial wilt in Solanaceae crops worldwide including Republic of Korea. Rso virulence predominantly relies on type III secreted effectors (T3Es). However, only a handful of Rso T3Es have been characterized. In this study, we investigated subcellular localization of and manipulation of plant immunity by 8 Rso T3Es predicted to harbor a nuclear localization signal (NLS). While 2 of these T3Es elicited cell death in both Nicotiana benthamiana and N. tabacum, only one was dependent on suppressor of G2 allele of skp1 (SGT1), a molecular chaperone of nucleotide-binding and leucine-rich repeat immune receptors. We also identified T3Es that differentially regulate flg22-induced reactive oxygen species production and gene expression. Interestingly, several of the NLS-containing T3Es translationally fused with yellow fluorescent protein accumulated in subcellular compartments other than the cell nucleus. Our findings bring new clues to decipher Rso T3E function in planta.

• Korean Journal of Materials Research
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• v.7 no.1
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• pp.33-39
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• 1997

Single phase pero~~skite lead lanthanum titanate thin films were fabricated on $Pt/Ti/SiO_2/Si$ substrates at the temperature of $480^{\circ}C$ by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR PECVD) using metal organic sources $Pb(DPM)_2$ pre-flowing treatment in ECIi oxygen plasma before fabricating PLT films 11romote the perovskite nucleation due to stable supplying of the $Pb(DPM)_2$ and providing the F'h-rich atmosphere in the early stage of deposition. $Pb(DPM)_2$ pie-flonring treatment enhanced the properties of PLT films. The charactcristics of the PLT filrris were investigated as a tunction of the flow rate of Ti-source. The PL'i' films were grown in a perovskite structure tvith (100) preferred orientation. The high X-ray diffraction intensity and dielectric constant were obtained from the stoichiometric perovskite $(Pb,La)TiO_3$.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.326-336
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• 2016

Saccharomyces cerevisiae is one of the most employed cell factories for the production of bioproducts. Although monomeric hexose sugars constitute the preferential carbon source, this yeast can grow on a wide variety of nitrogen sources that are catabolized through central nitrogen metabolism (CNM). To evaluate the effects of internal perturbations on nitrogen utilization, we characterized strains deleted or overexpressed in GLT1, encoding for one of the key enzymes of the CNM node, the glutamate synthase. These strains, together with the parental strain as control, have been cultivated in minimal medium formulated with ammonium sulfate, glutamate, or glutamine as nitrogen source. Growth kinetics, together with the determination of protein content, viability, and reactive oxygen species (ROS) accumulation at the single cell level, revealed that GLT1 modulations do not significantly influence the cellular physiology, whereas the nitrogen source does. As important exceptions, GLT1 deletion negatively affected the scavenging activity of glutamate against ROS accumulation, when cells were treated with H₂O₂, whereas Glt1p overproduction led to lower viability in glutamine medium. Overall, this confirms the robustness of the CNM node against internal perturbations, but, at the same time, highlights its plasticity in respect to the environment. Considering that side-stream protein-rich waste materials are emerging as substrates to be used in an integrated biorefinery, these results underline the importance of preliminarily evaluating the best nitrogen source not only for media formulation, but also for the overall economics of the process.

• Journal of Hydrogen and New Energy
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• v.23 no.3
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• pp.199-206
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• 2012

HC-SCR was conducted over Co-Pt/ZSM5 catalyst coated over 200 cpsi cordierite in the condition of atomspheric pressure and $200^{\circ}C-500^{\circ}C$. Weight ratio of Co/Pt determined from EDX analysis was 8/2, which was almost equal to the weight ratio at preparation step. XPS showed that nitrates within cobalt precursor and chlorine withn Pt precursor were removed. TEM result demonstrated that crystallite size of cobalt and Pt was under 5nm. Among these tested hydrocarbon reductants, isobutane ($i-C_4H_{10}$) showed the highest de-$NO_x$ yield of 80% under the condition of the mole ratio of reductant/NOx=1.0 at $180^{\circ}C$. De-$NO_x$ yield from HC-SCR was increased as the carbon number of hydrocarbon reductant was increased. The decrease of bonding energy between C and H of HC reductant played a role to increase of de-$NO_x$ yield, which indicated that the dissociation step of C-H bond of hydrocarbon molecule might be the rate determining step of HC-SCR. The increase of oxygen concentration in the feed resulted in the decrease of de-$NO_x$ yield but the increase of CO and $N_2O$ yield.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.40-47
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• 2014

In this paper, $Al_2O_3$ film deposited by thermal atomic layer deposition (ALD) with diluted $NH_4OH$ instead of $H_2O$ was suggested for passivation layer and anti-reflection (AR) coating of the p-type crystalline Si (c-Si) solar cell application. It was confirmed that the deposition rate and refractive index of $Al_2O_3$ film was proportional to the $NH_4OH$ concentration. $Al_2O_3$ film deposited with 5 % $NH_4OH$ has the greatest negative fixed oxide charge density ($Q_f$), which can be explained by aluminum vacancies ($V_{Al}$) or oxygen interstitials ($O_i$) under O-rich condition. $Al_2O_3$ film deposited with $NH_4OH$ 5 % condition also shows lower interface trap density ($D_{it}$) distribution than those of other conditions. At $NH_4OH$ 5 % condition, moreover, $Al_2O_3$ film shows the highest excess carrier lifetime (${\tau}_{PCD}$) and the lowest surface recombination velocity ($S_{eff}$), which are linked with its passivation properties. The proposed $Al_2O_3$ film deposited with diluted $NH_4OH$ is very promising for passivation layer and AR coating of the p-type c-Si solar cell.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.1005-1014
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• 2012

The understanding of the relationship between ammonia-oxidizing bacteria (AOB) communities in activated sludge and the operational treatment parameters supports the control of the treatment of ammonia-rich wastewater. The modifications of treatment parameters by alteration of the number and length of aerobic and anaerobic stages in the sequencing batch reactor (SBR) working cycle may influence the efficiency of ammonium oxidation and induce changes in the AOB community. Therefore, in the research, the impact of an SBR cycle mode with alternating aeration/mixing conditions (7 h/1 h vs. 4 h/5.5 h) and volumetric exchange rate (n) on AOB abundance and diversity in activated sludge during the treatment of anaerobic sludge digester supernatant at limited oxygen concentration in the aeration stage (0.7 mg $O_2/l$) was assessed. AOB diversity expressed by the Shannon-Wiener index (H') was determined by the cycle mode. At aeration/mixing stage lengths of 7 h/1 h, H' averaged $2.48{\pm}0.17$, while at 4 h/5.5 h it was $2.35{\pm}0.16$. At the given mode, AOB diversity decreased with increasing n. The cycle mode did not affect AOB abundance; however, a higher AOB abundance in activated sludge was promoted by decreasing the volumetric exchange rate. The sequences clustering with Nitrosospira sp. NpAV revealed the uniqueness of the AOB community and the simultaneously lower ability of adaptation of Nitrosospira sp. to the operational parameters applied in comparison with Nitrosomonas sp.