• The Korean Journal of Physiology and Pharmacology
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• v.13 no.1
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• pp.39-47
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• 2009

Gaegurin 4(GGN 4), an antimicrobial peptide isolated from a Korean frog, is five times more potent against Gram-positive than Gram-negative bacteria, but has little hemolytic activity. To understand the mechanism of such cell selectivity, we examined GGN4-induced $K^+$ efflux from target cells, and membrane conductances in planar lipid bilayers. The $K^+$ efflux from Gram-positive M. luteus(2.5 ${\mu}g/ml$) was faster and larger than that from Gram-negative E. coli(75 ${\mu}g/ml$), while that from RBC was negligible even at higher concentration(100 ${\mu}g/ml$). GGN4 induced larger conductances in the planar bilayers which were formed with lipids extracted from Gram-positive B. subtilis than in those from E. coli(p<0.01), however, the effects of GGN4 were not selective in the bilayers formed with lipids from E. coli and red blood cells. Addition of an acidic phospholipid, phosphatidylserine to planar bilayers increased the GGN4-induced membrane conductance(p<0.05), but addition of phosphatidylcholine or cholesterol reduced it(p<0.05). Transmission electron microscopy revealed that GGN4 induced pore-like damages in M. luteus and dis-layering damages on the outer wall of E. coli. Taken together, the present results indicate that the selectivity of GGN4 toward Gram-positive over Gram-negative bacteria is due to negative surface charges, and interaction of GGN4 with outer walls. The selectivity toward bacteria over RBC is due to the presence of phosphatidylcholine and cholesterol, and the trans-bilayer lipid asymmetry in RBC. The results suggest that design of selective antimicrobial peptides should be based on the composition and topology of membrane lipids in the target cells.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.8
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• pp.1117-1123
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• 2012

The effect of duckweed (DW) supplementation was evaluated on dry matter intake (DMI), presence and duration of estrus, percentage of ewes repeating estrus and pregnancy rate, as well as the concentration of progesterone ($P_4$) in multiparous crossbred ewes from Pelibuey, Dorper, and Katahdin breeds, fed with Taiwan grass hay (TWH). Eighteen ewes with $39.7{\pm}4kg$ mean body weight, kept in individual pens, were randomly assigned to one of the following treatments: $T_1$: TWH, $T_2$: TWH plus 200 g DW, $T_3$: TWH plus 300 g DW. The ewes were synchronized with 40 mg fluorogestone acetate (FGA) and 400 UI equine chorionic gonadotropin (eCG). Data were analyzed as a completely randomized design using the GLM procedure. DW supplementation had no effect on dry matter intake (p>0.05); however, a slight decrease of TWH intake was observed as DW supplementation increased. No differences (p>0.05) were found in the beginning of estrus, percentage of ewes presenting it, its duration, or pregnancy rate. There were no differences (p>0.05) on $P_4$ concentration among treatments, or $treatment{\times}period$ interaction (p>0.05). However the period was significant (p<0.01), since the $P_4$ levels increased as time increased after the removal of the FGA device and eCG application.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.988-992
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• 2011

$CO_2$ adsorption on mineral sorbents has a potential to sequester $CO_2$. This study used a density functional theory (DFT) study of $CO_2$ adsorption on barium oxide (BaO) in the presence of $H_2O$ to determine the role of $H_2O$ on the $CO_2$ adsorption properties on the ($2{\times}2$; $11.05\;{\AA}{\times}11.05\;{\AA}$) BaO (100) surface because BaO shows a high reactivity for $CO_2$ adsorption and the gas mixture of power plants generally contains $CO_2$ and $H_2O$. We investigated the adsorption properties (e.g., adsorption energies and geometries) of a single $CO_2$ molecule, a single $H_2O$ molecule on the surface to achieve molecular structures and molecular reaction mechanisms. In order to evaluate the coordinative effect of $H_2O$ molecules, this study also carried out the adsorption of a pair of $H_2O$ molecules, which was strongly bounded to neighboring (-1.91 eV) oxygen sites and distant sites (-1.86 eV), and two molecules ($CO_2$ and $H_2O$), which were also firmly bounded to neighboring sites (-2.32 eV) and distant sites (-2.23 eV). The quantum mechanical calculations show that $H_2O$ molecule does not influence on the chemisorption of $CO_2$ on the BaO surface, producing a stable carbonate due to the strong interaction between the $CO_2$ molecule and the BaO surface, resulting from the high charge transfer (-0.76 e).

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.888-893
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• 2000

The present study was conducted to evaluate heterosis effects of body weight and jumping height for successive generations of rotational crossing using two subspecies of mice which are very different in body weight and in genetic relationship from each other. Domesticated laboratory mouse $CF_{{\sharp}1}$ (C) and Yonakuni wild mouse (Y) were used as materials. Two groups of rotational crossing was made according to the parent used at the beginning of crosses, C male$\times$Y female and Y male$\times$C female. These crosses were done to produce the first ($G_1$ and $G_1{^{\prime}}$), second ($G_2$ and $G_2{^{\prime}}$) and third generations ($G_3$ and $G_3{^{\prime}}$) with sire used was alternated. Individual body weights were weighed at 1 (wk1), 3 (wk3), 6 (wk6) and 10 weeks of age (wk10) and jumping heights were measured at six weeks of age (wk6). Only the first litter used. For body weight, results of this study showed that genetic group effects were significant (p<0.01) source of variation at all ages studied. Sex effects were significant (p<0.01) at wk3, wk6 and wk10, but not at wk1. Significant interaction effects (p<0.01) between genetic group and sex were found at wk6 and wk10. The C mice with large maternal effects produced heavier offspring body weight and crosses using sire of this subspecies maintained heavy weight compared to wild Y mouse sire that has small body size. Heterosis tended to exist at the rotational crossing started from Y male C female. For jumping height, effects of genetic group and sex were significant, sire and dam effects (heterosis) exhibited from the first to third generations, and no maternal effects were observed.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1263-1272
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• 1999

The effects of carnitine in diets with or without added fat (5% lard or soybean oil) were evaluated in 72 Large White ${\times}$ Landrace ${\times}$ Duroc pigs weaned at 35 days of age. Pigs were fed a 1.30% lysine corn-soybean basal diet+15% dried whey+4% fish meal with carnitine at 0 or 50 mg/kg and either 0% added fat, 5% soybean oil or 5% lard for 6 weeks in a $2{\times}3$ factorial trial (6 treatments, 3 pens per treatment, 4 pigs per pen). Addition of carnitine increased average daily gain (ADG) and average daily feed intake (ADFI) in the second two weeks of the six-week trial and overall, but had no significant effect on feed per gain (F/G). Lard alone depressed ADG (p<0.05) in the last two weeks of the trial and overall, but the ADG for pigs fed lard+carnitine was similar to the control. Lard reduced feed intake in the first two weeks of the trial (p<0.05). Carnitine reduced the percentage of pigs with poor (ADG<375 g/d) growth (15 vs 40%; p<0.05). The greater uniformity of growth was most evident in low-weaning-weight pigs in the second period (16 vs 62%, p<0.005). Addition of fat did not produce any positive effect on uniformity and had no interaction with carnitine on uniformity. Carnitine addition increased serum total carnitione and short-chain acyl-carnitine levels (p<0.05), but did not modify free carnitine levels. Serum carnitine levels were lower at weaning than at 14, 28, or 39 days after weaning (p<0.05). Carnitine increased serum protein levels on day 14 (p<0.05). Addition of fat in the form of soybean oil or lard did not improve piglet growth performance. Addition of 50 mg/kg of carnitine to the diet of weanling pigs enhanced postweaning performance.

• Korean Journal of Cognitive Science
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• v.26 no.3
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• pp.279-300
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• 2015

Present research was carried out on the level of exploration to verify that good luck increases probabilistic framing effect but bad luck decrease the effect. And we organized an experiment that designed experience of luck (good luck vs. bad luck vs. control) ${\times}$ probabilistic frame (high vs. low) and observed whether people response based on probabilistic frame or not. As a result, we observed the two-way interaction where experience of good luck increased probabilistic framing effect, while experience of bad luck decreased the effect (Figure 1). We expect to see more studies of contextual framing effect besides probabilistic frame (e.g., positive vs. negative; loss related to context vs. loss irrelevant to context).

• Wind and Structures
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• v.38 no.4
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• pp.261-275
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• 2024

Before performing an experimental study on the downburst-generated wave, it is necessary to examine the scale effects and corresponding corrections or compensations. Analysis of similarity is conducted to conclude the non-dimensional force ratios that account for the dynamic similarity in the interaction of downburst with wave between the prototype and the scale model, along with the corresponding scale factors. The fractional volume of fluid (VOF) method in association with the impinging jet model is employed to explore the characteristics of the downburst-generated wave numerically, and the validity of the proposed scaling method is verified. The study shows that the location of the maximum radial wind velocity in a downburst-wave field is a little higher than that identified in a downburst over the land, which might be attributed to the presence of the wave which changes the roughness of the underlying surface of the downburst. The impinging airflow would generate a concavity in the free surface of the water around the stagnation point of the downburst, with a diameter of about two times the jet diameter (D_jet). The maximum wave height appears at the location of 1.5D_jet from the stagnation point. Reynolds number has an insignificant influence on the scale effects, in accordance with the numerical investigation of the 30 scale models with the Reynolds number varying from 3.85 × 10⁴ to 7.30 × 10⁹. The ratio of the inertial force of air to the gravitational force of water, which is denoted by G, is found to be the most significant factor that would affect the interaction of downburst with wave. For the correction or compensation of the scale effects, fitting curves for the measures of the downburst-wave field (e.g., wind profile, significant wave height), along with the corresponding equations, are presented as a function of the parameter G.

• Journal of The Korean Astronomical Society
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• v.36 no.3
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• pp.89-95
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• 2003

Observations of dark matter dominated dwarf and low surface brightness disk galaxies favor density profiles with a flat-density core, while cold dark matter (CDM) N-body simulations form halos with central cusps, instead. This apparent discrepancy has motivated a re-examination of the microscopic nature of the dark matter in order to explain the observed halo profiles, including the suggestion that CDM has a non-gravitational self-interaction. We study the formation and evolution of self-interacting dark matter (SIDM) halos. We find analytical, fully cosmological similarity solutions for their dynamics, which take proper account of the collisional interaction of SIDM particles, based on a fluid approximation derived from the Boltzmann equation. The SIDM particles scatter each other elastically, which results in an effective thermal conductivity that heats the halo core and flattens its density profile. These similarity solutions are relevant to galactic and cluster halo formation in the CDM model. We assume that the local density maximum which serves as the progenitor of the halo has an initial mass profile ${\delta}M / M {\propto} M^{-{\epsilon}$, as in the familiar secondary infall model. If $\epsilon$ = 1/6, SIDM halos will evolve self-similarly, with a cold, supersonic infall which is terminated by a strong accretion shock. Different solutions arise for different values of the dimensionless collisionality parameter, $Q {\equiv}{\sigma}p_br_s$, where $\sigma$ is the SIDM particle scattering cross section per unit mass, $p_b$ is the cosmic mean density, and $r_s$ is the shock radius. For all these solutions, a flat-density, isothermal core is present which grows in size as a fixed fraction of $r_s$. We find two different regimes for these solutions: 1) for $Q < Q_{th}({\simeq} 7.35{\times} 10^{-4}$), the core density decreases and core size increases as Q increases; 2) for $Q > Q_{th}$, the core density increases and core size decreases as Q increases. Our similarity solutions are in good agreement with previous results of N-body simulation of SIDM halos, which correspond to the low-Q regime, for which SIDM halo profiles match the observed galactic rotation curves if $Q {\~} [8.4 {\times}10^{-4} - 4.9 {\times} 10^{-2}]Q_{th}$, or ${\sigma}{\~} [0.56 - 5.6] cm^2g{-1}$. These similarity solutions also show that, as $Q {\to}{\infty}$, the central density acquires a singular profile, in agreement with some earlier simulation results which approximated the effects of SIDM collisionality by considering an ordinary fluid without conductivity, i.e. the limit of mean free path ${\lambda}_{mfp}{\to} 0$. The intermediate regime where $Q {\~} [18.6 - 231]Q_{th}$ or ${\sigma}{\~} [1.2{\times}10^4 - 2.7{\times}10^4] cm^2g{-1}$, for which we find flat-density cores comparable to those of the low-Q solutions preferred to make SIDM halos match halo observations, has not previously been identified. Further study of this regime is warranted.

• Nuclear Engineering and Technology
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• v.4 no.3
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• pp.203-213
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• 1972

The precipitation sequence of Inconel 718 alloy, aged at $760^{\circ}C$ for times up to 200 hr, has been studied by means of electron microscopy and X-ray diffraction methods. The dominant hardening phase was identified as the metastable, body-centered tetragonal $Ni_3Nb$ Phase in the morphology of platelets. The other phases identified in the aging sequence were (Nb, Ti)C and the stable acicular phase of orthorhombic $Ni_3Nb.$ The observations were made on the interaction of dislocations with the precipitates in the underaged condition. The shearing of the precipitates and the planar defects, e.g., stacking faults on i1101 planes of the intermetallic phase, were observed.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.12
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• pp.1930-1938
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• 2018

Objective: The present study attempted to determine safe and sufficient growth promoters in poultry feeding. Methods: A total of 520 seven-day-old quail chicks were randomly allotted to eight treatment groups in a $4{\times}2$ factorial design experiment to evaluate the effect of different levels of humic acid (HA) and black cumin (BC) seed and their interactions on growth, carcass traits, gut microbes, and blood chemistry of growing quails. Quails were randomly distributed into 8 groups in a $4{\times}2$ factorial design, included 4 HA levels (0, 0.75, 1.5, and 2.25 g/kg diet) and 2 BC levels (0 or 5 g/ kg diet). Results: Increasing HA level associated with a gradual increase in final weight, feed intake and body weight gain along with an improvement in feed conversion ratio. Dietary addition of 5 g BC powder/kg diet gave similar results. The highest level of HA (2.25 g/kg diet) recorded the best values of carcass weight, breast yield, intestinal length, and intestinal weight comparing with the control and other HA levels. Total viable microbial counts decreased (p<0.05) with increasing levels of HA except the intermediate level (1.5 g/kg diet). The concentration of serum cholesterol and low density lipoprotein (excluding that 0.75 g HA) decreased (p<0.05) and high density lipoprotein increased (p = 0.034) along with increasing HA level. The interaction between the $2.25g\;HA{\times}5g$ gave the best results regarding most studied parameters. Conclusion: These findings indicated that HA combined with BC could be used as effective growth promoters, with the recommended level being 2.25 g HA+5 g BC/kg of quail diet.