Divergences in morphological changes and antioxidant responses in salt-tolerant and salt-sensitive rice seedlings after salt stress

Lee, M.H.,Cho, E.J.,Wi, S.G.,Bae, H.,Kim, J.E.,Cho, J.Y.,Lee, S.,Kim, J.H.,Chung, B.Y. Gauthier-Villars ; Elsevier Science Ltd 2013 Plant physiology and biochemistry Vol.70 No.-

Salinization plays a primary role in soil degradation and reduced agricultural productivity. We observed that salt stress reversed photosynthesis and reactive oxygen scavenging responses in leaves or roots of two rice cultivars, a salt-tolerant cultivar Pokkali and a salt-sensitive cultivar IR-29. Salt treatment (100 mM NaCl) on IR-29 decreased the maximum photochemical efficiency (Fv/Fm) and the photochemical quenching coefficient (qP), thereby inhibiting photosynthetic activity. By contrast, the salt treatment on Pokkali had the converse effect on Fv/Fm and qP, while increasing the nonphotochemical quenching coefficient (NPQ), thereby favoring photosynthetic activity. Notably, chloroplast or root cells in Pokkali maintained their ultrastructures largely intact under the salt stress, but, IR-29 showed severe disintegration of existing grana stacks, increase of plastoglobuli, and swelling of thylakoidal membranes in addition to collapsed vascular region in adventitious roots. Pokkali is known to have higher hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>)-scavenging enzyme activities in non-treated seedlings, including ascorbate peroxidase, catalase, and peroxidase activities. However, these enzymatic activities were induced to a greater extent in IR-29 by the salt stress. While the level of endogenous H<SUB>2</SUB>O<SUB>2</SUB> was lower in Pokkali than in IR-29, it was reversed upon the salt treatment. Nevertheless, the decreased amount of H<SUB>2</SUB>O<SUB>2</SUB> in IR-29 upon the salt stress didn't result in a high scavenging activity of total cell extracts for H<SUB>2</SUB>O<SUB>2</SUB>, as well as O<SUB>2</SUB>?<SUP>-</SUP> and ?OH species. The present study suggests that the tolerance to the moderate salinity in Pokkali derives largely from the constitutively maintained antioxidant enzymatic activities as well as the induced antioxidant enzyme system.

Helicon wave coupling in KSTAR plasmas for off-axis current drive in high electron pressure plasmas

Wang, S.J.,Wi, H.H.,Kim, H.J.,Kim, J.,Jeong, J.H.,Kwak, J.G. IOP 2017 Nuclear fusion. Fusion nucléaire. &n.Illiga Vol.57 No.4

<P>A helicon wave current drive is proposed as an efficient off-axis current drive in the high electron <I>β</I> plasmas that are expected in fusion reactors. A high frequency helicon wave coupling was analyzed using the surface impedance at a plasma boundary. A slow wave coupling, which may compete with the helicon wave coupling at a frequency of 500 MHz, is estimated to be lower than the fast wave coupling by an order of magnitude in the KSTAR edge plasma density and in practical Faraday shield misalignment with the magnetic pitch. A traveling wave antenna, which is a two port combline antenna, was analyzed using a simplified lumped element model. The results show that the traveling wave antenna provides load resiliency because of its insensitivity to loading resistance, provided that the loading resistance at a radiating element is limited within a practical range. The combline antenna is attractive because it does not require a matching system and exhibits a high selectivity of parallel refractive index. Based on the analysis, a seven element combline antenna was fabricated and installed at an off-mid-plane offset of 30 cm from the mid-plane in KSTAR. The low power RF characteristics measured during several plasma discharges showed no evidence of slow wave coupling. This is consistent with the expectation made through the surface impedance analysis which predicted low slow wave coupling. The wave coupling to the plasma is easily controlled by a radial outer-gap control and gas puffing. No plasma confinement degradation was observed during the radial outer-gap control of up to 3 cm in H-mode discharges. In a ELMy plasmas, only a small reflection peak was observed during a very short portion of the ELM bursting period. If the number of radiating elements is increased for high power operation, then complete load resiliency can be expected. A very large coupling can be problematic for maintaining a parallel refractive index, although this issue can be mitigated by increasing the number of elements.</P>

유동층 반응기를 이용한 고온건식 탈황

이창근,위영호 ( C . K . Yi,Y . H . Wi ) 한국화학공학회 1996 화학공학의이론과응용 Vol.2 No.2

볏짚 섬유소의 반추미생물 Ruminococcus albus F-40 에 의한 분해양태에 관한 연구

김윤수,위승곤,최봉환,명규호 한국축산학회 1997 한국축산학회지 Vol.39 No.5

Chemical and ultrastructural characteristics of rice straw degradation by ruminal cellulolytic bacterium, Ruminococcus albus F-40, were investigated. The degadation of rice straw and the adhesion rate of bacteria to the substrates increased with the decrease of cellulose crystallinity, suggesting the preferential degradation of amorphorous cellulose by R. albus. Polarized light microscopy and X-ray diffraction analyses, however, showed that crystalline cellulose in rice straw was also degraded by R. albus FT-IR spectra indicated that hemicellulose was also degraded by this bacterium. Electron microscopic(EM) investigations showed the protuberant structures on the surface of R. albus. Glycocalyx extended from the bacterial surface adhered tightly to the cellulosic substrates and vesicles occurred to the surface of cellulose substrates under the degradation. Cellulosome-like structures occurred on the surface of bacterial cells and on the cellulose microfibrils as well. EM examinations revealed that the degradation of cellulose by R. albus was proceeded as 1) adhesion of bacterium on the substrates 2) hemicellulose degradation 3) cut-off of axial fiber cellulose and 4) defibrillation of cellulose microfibril. Immuno-EM studies using the polyclonal antibodies of endocellulase from bacterial cell surface showed the intense gold labelling on the cellulose of rice straw at the beginning stage of degradation. Positive gold labelling in vesicles and glycocalyx indicated that these surface structures were involved in the degradation of cellulose. Catalytic domain of endocellulase was localized externally along the axis of cellulose microfibrils, indicating the direct involvement of this enzyme fraction in the degradation of cellulose.

Power deposition of H minority heating with a new compact ICRF antenna in KSTAR

Lee H. Y.,Kang J. S.,Wi H. H.,Wang S. J.,Kwak J. G.,Saito K. 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.78 No.11

The new compact ICRH antenna (CIA) with low electric field and conjugate-T has been installed in KSTAR. It is essential for studying the effect on the KSTAR plasma of H minority heating as a main ICRH scheme. The TRANSP-TORIC code has been adopted for analyzing the ICRH effect. The calculation using TRANSP-TORIC has been conducted with an additional 1 MW of ICRH power to the KSTAR operation at B0 = 2.0 T. About 75% of the ICRH power has coupled to the H minority heating, and most of the power of H minority heating has contributed to the energy of D majority ions and electrons. The deposited profile of the minority heating power varies with the concentration rate of the H minority ions and shows the possibility of producing energetic particles which appears to the increasing energy of D majority ions. The power of the H minority heating has good coupling to the majority ions in the broad range of 5 < n// < 35, including n// of the newly installed CIA in KSTAR.

Pre-treatment of donor with 1-deamino-8-d-arginine vasopressin could alleviate early failure of porcine xenograft in a cobra venom factor treated canine recipient

Kang, H.J.,Lee, G.,Kim, J.Y.,Lee, S.H.,Wi, H.C.,Hwang, P.G.,Chung, D.H.,Kim, Y.T. Springer International 2005 European journal of cardio-thoracic surgery Vol.28 No.1

Objective: Unlike cardiac or renal xenotransplants, the depletion of complement using cobra venom factor (CVF) does not improve pulmonary xenograft survival. Several cases suggest that the swine von Willebrand factor (vWF) may play a major role in presenting a different pathogenesis of pulmonary xenograft dysfunction from other organs. To evaluate the role of vWF and the complement system in mediating hyperacute vascular injury of pulmonary xenografts and elucidate pathogenesis of the injury, we performed swine-to-canine orthotropic single lung xenotransplantation after pre-treatment of 1-deamino-8-d-arginine vasopressin (DDAVP) and CVF. Methods: We set up three groups for lung xenotransplantation: group I served as the control group; group II, recipients pre-treated with CVF; group III, donors pre-treated with DDAVP (9mg/kg, 3 days)/recipients pre-treated with CVF (60u/kg). Hemodynamic data, coagulation and complement system parameters, and grafted lung pathologies were examined serially for 3h after transplantation. Results: DDAVP infusion reduced the vWF content in swine lung tissue in vivo (7.7+/-2.4AU/mg vs 16.0+/-5.6AU/mg, P<0.0001). Infusion of CVF 24h prior to transplantation effectively depleted the recipient's serum C3 and complement hemolytic activity below the detectable range. Regardless of the use of CVF, both groups I and II transplanted with unmodified grafts showed an immediate drop in leukocytes and platelet counts after transplantation. However, in group III, in recipients transplanted with DDAVP pre-treated swine lung, the platelet count did not decrease after transplantation (P=0.0295). The decrease of plasma antithrombin and fibrinogen tended to be attenuated in group III. Light microscopic examination revealed extensive vascular thromboses in both capillary and larger vessels, as well as early pulmonary parenchymal damage in groups I and II, but were rarely observed in group III. Conclusions: Complement inhibition alone was not enough to alleviate intravascular thrombosis, the main pathology in pulmonary xenotransplantation. Pre-infusion of DDAVP to the donor animal was effective in preventing platelet sequestration and attenuated intravascular thrombosis. It is suggested that the strategies targeting vWF would be promising for successful pulmonary xenotransplantation. tation.

Localized electrical energy concentration method for multi-electrode bioimpedance measurement

H. Kwon,H. Wi,B. Karki,E.J. Lee,A. McEwan,E.J. Woo,B. Harrach,J.K. Seo,T.I. Oh 한국산업응용수학회 2012 한국산업응용수학회 학술대회 논문집 Vol.7 No.2

ANALYZING UNCERTAINTY IN EVALUATION OF VEHICLE FUEL ECONOMY USING FTP-75

H. WI,박진일 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.3

Fuel economy is one of the major issues in the development of automobiles, along with performance and drivability. During a fuel economy test, the driver should follow the target schedule as closely as possible. However, it is impossible even for a skillful driver to completely follow the prescribed speed pattern; therefore, a speed tolerance, the extent to which violation of the prescribed speed pattern is permitted, is approved by the administrator of the test and has been used during fuel economy certification tests. Consequently, there is a difference in speed every time that a fuel economy certification test is conducted and therefore there is also a deviation in the certified fuel economy. Nevertheless, no research has been carried out into the deviation of fuel economy according to the observance of the target schedule by a driver. In this respect, this research aims to investigate the deviation of fuel economy which may take place during a fuel economy certification test. Fuel economy deviation is examined in three cases: driving at the highest or lowest speed in the defined range of speed tolerance, driving with the maximum or minimum tolerated acceleration, and driving with periodic variation from the prescribed speed. The periodic variation effects to the fuel economy deteriorated by more than 8%.

A comparative study on enzymatic hydrolysis of kenaf from two different harvest time-points, with- and without pretreatment

Wi, S.G.,Kim, S.B.,Lee, D.S.,Kim, H.M.,Bae, H.J. Elsevier 2015 INDUSTRIAL CROPS AND PRODUCTS Vol.76 No.-

Kenaf biomass is potentially a valuable feedstock for bio-energy production due to fast growth of this plant, and its high capacity for carbon fixation and accumulation of carbohydrates. In this study, biomass productivity, chemical composition and physical properties of kenaf were investigated at two different harvest times. The average dry weight of early harvested biomass (EH, 109.0g/plant) was lower than that of late harvested biomass (LH, 132.3g/plant). However, the daily growth rates for EH and LH were 1.45 and 1.28g/d, respectively. There was no significant difference in carbohydrate content between EH- and LH-kenaf, while lignin content increased with higher S/G ratio in LH-kenaf. The enzymatic conversion rates of EH- and LH-kenaf with/without popping pretreatment were 90.4%/41.2% and 65.0%/27.5%, respectively. We suggest that early harvest has a positive impact on kenaf biomass, which had a lower lignin content and cellulose crystallinity.

Design and RF test of a prototype traveling wave antenna for helicon current drive in KSTAR

Wi, H.H.,Wang, S.J.,Kim, H.J.,Kwak, J.G. Elsevier 2018 Fusion engineering and design Vol.126 No.-

<P><B>Abstract</B></P> <P>Non-inductive current drive by fast wave at very high ion cyclotron harmonics, known as ‘helicons’ has the potential for high off-axis current drive efficiency compared with the other known non-inductive current drive techniques. However, non-inductive current drive by helicon wave has not been validated experimentally. To validate its anticipated performance experimentally, an antenna design is one of the most important issues. A Traveling wave antenna has particularly valuable features for launching the fast wave such as load resiliency, narrow n<SUB>||</SUB> spectrum, and simple RF circuits without additional-external matching systems. Low power level helicon wave coupling experiments has been conducted successfully using a mock-up TWA in KSTAR. In the next step, in order to investigate a high power performance, a new prototype TWA based on the mock-up TWA has been designed, fabricated and measured for a medium power (100–300kW) RF system. The prototype TWA having a Faraday shield was made of copper and consists of 10 current straps with 5inch coaxial feeding lines as input and output ports. The detailed design parameters and electromagnetic characteristics of prototype TWA are discussed.</P>