12 research outputs found

    The First Very Long Baseline Interferometry Image of 44 GHz Methanol Maser with the KVN and VERA Array (KaVA)

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    We have carried out the first very long baseline interferometry (VLBI) imaging of 44 GHz class I methanol maser (7_{0}-6_{1}A^{+}) associated with a millimeter core MM2 in a massive star-forming region IRAS 18151-1208 with KaVA (KVN and VERA Array), which is a newly combined array of KVN (Korean VLBI Network) and VERA (VLBI Exploration of Radio Astrometry). We have succeeded in imaging compact maser features with a synthesized beam size of 2.7 milliarcseconds x 1.5 milliarcseconds (mas). These features are detected at a limited number of baselines within the length of shorter than approximately 650 km corresponding to 100 Mlambda in the uv-coverage. The central velocity and the velocity width of the 44 GHz methanol maser are consistent with those of the quiescent gas rather than the outflow traced by the SiO thermal line. The minimum component size among the maser features is ~ 5 mas x 2 mas, which corresponds to the linear size of ~ 15 AU x 6 AU assuming a distance of 3 kpc. The brightness temperatures of these features range from ~ 3.5 x 10^{8} to 1.0 x 10^{10} K, which are higher than estimated lower limit from a previous Very Large Array observation with the highest spatial resolution of ~ 50 mas. The 44 GHz class I methanol maser in IRAS 18151-1208 is found to be associated with the MM2 core, which is thought to be less evolved than another millimeter core MM1 associated with the 6.7 GHz class II methanol maser.Comment: 19 pages, 3 figure

    Evaluation of Air Temperature, Photoperiod and Light Intensity Conditions to Produce Cucumber Scions and Rootstocks in a Plant Factory with Artificial Lighting

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    Air temperature and light conditions are important factors not only to produce high-quality seedlings but also to promote energy efficiency in a plant factory with artificial lighting. In this study, we conducted two experiments in order to investigate the favorable conditions of air temperature, light intensity and photoperiod for the production of cucumber scions and rootstocks in a plant factory with artificial lighting. Cucumber scions and rootstocks were cultivated in two combined treatments: the combination of three different levels of difference between the day and night temperature (DIF), 25/20, 26/18 and 27/16 °C and five different light intensity conditions of photosynthetic photon flux, 50, 100, 150, 200 and 250 μmol·m−2·s−1 was set for the first experiment, and the combination of three different photoperiod conditions, 12, 16 and 20 h·d−1 and five different light intensity conditions, 50, 100, 150, 200 and 250 μmol·m−2·s−1 was set for the second experiment. In the air temperature and light intensity treatments, the hypocotyl elongation of cucumber scions and rootstocks was affected more largely by light intensity than DIF. The highest DIF treatment (27/16 °C) affected negatively on the accumulation of dry mass. On the contrary, the smallest DIF treatment (25/20 °C) was favorable for seedling growth due to lesser stress by rapid change of air temperature between photo- and dark-period. In the photoperiod and light intensity treatments, an increased DLI (daily light integral) promoted the growth of scions and rootstocks. Under the same DLI condition, the growth of scions and rootstocks increased with increasing photoperiod and decreasing light intensity. In both of experiments, while the dry weight increased with increasing the light intensity, the light use efficiencies were reduced by increasing the light intensity. Considering the growth and quality of seedlings and energy efficiency, the optimal environment conditions were represented by 25/20 °C of air temperature, 150 μmol·m−2·s−1 of light intensity and 16 h·d−1 of photoperiod

    Effect of Cation Influx on the Viability of Freeze-Dried <em>Lactobacillus brevis</em> WiKim0069

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    Extension of the storage stability of freeze-dried lactic acid bacteria is important for industrialization. In this study, the effect of cation influx from soy powder, which contains high amounts of cations, as a cryoprotective agent on the viability of freeze-dried Lactobacillus brevis WiKim0069 was tested. Compared to that in the absence of the soy powder, bacterial viability was significantly higher in the presence of soy powder. Approximately 4.7% of L. brevis WiKim0069 survived in the absence of the protective agent, whereas 92.8% viability was observed in the presence of soy powder. However, when cations were removed from the soy powder by using ethylenediaminetetraacetic acid (EDTA) and a cationic resin filter, the viability of L. brevis WiKim0069 decreased to 22.9–24.7%. When the soy powder was treated with ethylene glycol tetraacetic acid, the viability was higher than when it was pretreated with EDTA and a cationic resin filter, suggesting that Mg2+ had a role in enhancing the viability of L. brevis WiKim0069. Cold adaptation at 10 °C prior to freeze-drying had a positive effect on the storage stability of freeze-dried L. brevis WiKim0069, with 60.6% viability after 56 days of storage. A decrease in the fluorescence polarization value indicated an increase in membrane fluidity, which regulates the activity of ion channels present in the cell membrane. Cold adaptation caused activation of the cation channels, resulting in increased intracellular influx of cations, i.e., Ca2+ and Mg2+. These results suggest that cold adaptation can be used to improve the storage stability of L. brevis WiKim0069

    Enhanced Sensitivity of Iontronic Graphene Tactile Sensors Facilitated by Spreading of Ionic Liquid Pinned on Graphene Grid

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    Iontronic graphene tactile sensors (i-GTS) composed of a top floating graphene electrode and an ionic liquid droplet pinned on a bottom graphene grid, which can dramatically enhance the performance of capacitive-type tactile sensors, are presented. When mechanical stress is applied to the top floating electrode, the i-GTS operates in one of the following three regimes: air-air, air-electric double layer (EDL) transition, or EDL-EDL. Once the top electrode contacts the ionic liquid in the i-GTS, the spreading behavior of the ionic liquid causes a capacitance transition (from a few pF to over hundreds of pF). This is because EDLs are formed at the interfaces between the electrodes and the ionic liquid. In this case, the pressure sensitivity increases to approximate to 31.1 kPa(-1) with a gentle touch. Under prolonged application of pressure, the capacitance increases gradually, mainly due to the contact line expansion of the ionic liquid bridge pinned on the graphene grid. The sensors exhibit outstanding properties (response and relaxation times below 80 ms, and stability over 300 cycles) while demonstrating ultimate signal-to-noise ratios in the array tests. The contact-induced spreading behavior of the ionic liquid is the key for boosting the sensor performance.11Nsciescopu

    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

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    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 (9 mg/kg, 3 days)/recipients pre-treated with CVF (60 u/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+/-2.4 AU/mg vs 16.0+/-5.6 AU/mg, P < 0.0001). Infusion of CVF 24 h 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.This study was supported by a grant of the Korea Health 21 R&D Project, Ministry of Health and Welfare, Republic of Korea (Project No.: 0405-BO02-0205-0001) and National R&D Program Grant of The Ministry of Science and Technology (M1031006007-03B4606-00710

    Effective approach to organic acid production from agricultural kimchi cabbage waste and its potential application.

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    The biotransformation of agricultural waste into valuable chemicals represents a promising approach in the field of biorefining. Herein, a general but highly efficient and robust process is reported for the production of organic acid from kimchi cabbage waste using lactic acid bacteria. The organic acid produced was tested for efficacy as a biological control agent. Lactobacillus sakei WiKim31 and L. curvatus WiKim38 could efficiently produce organic acids including lactic acid (12.1 and 12.7 g/L), fumaric acid (7.4 and 7.1 g/L), and acetic acid (4.5 and 4.6 g/L) from kimchi cabbage waste (3% substrate loading, w/v) by simultaneous saccharification and fermentation processes for 48 h, and the culture filtrate induced complete mortality of J2s Meloidogyne incognita at 2.5% concentration. These results suggested that lactic acid bacteria L. sakei WiKim31 and L. curvatus WiKim38 can efficiently produce organic acids, and the culture filtrate can be applied as a microbial nematicide
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