• Animal Bioscience
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• 제35권6호
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• pp.916-926
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• 2022

Objective: This study was conducted to evaluate the effects of medium chain triglycerides (MCT) with organic acids (OA) on growth performance, fecal score, blood profiles, intestinal morphology, and nutrient digestibility in weaning pigs. Methods: A total of 120 weaning pigs ([Yorkshire×Landrace]×Duroc) with an average body weight (BW) of 8.00±0.87 kg were assigned in five treatments considering sex and initial BW in 3 replications with 8 pigs per pen in a randomized complete block design. The experimental diets included a corn-soybean meal based basal diet with or without 0.1% or 0.2% MCT and 0.1% OA. The pigs were fed the diets for 5 weeks (phase 1, 0 to 2 weeks; phase 2, 3 to 5 weeks). A total of 15 barrows with an average BW of 12.48±0.37 kg were used to evaluate the nutrient digestibility by total collection method. The BW and feed intake were measured at the end of each phase. Blood samples and small intestine samples were collected at the end of each phase, too. Results: Supplementing 0.1% MCT with 0.1% OA showed greater BW for week 5 and average daily gain (ADG) for overall period than control diet. Supplementing 0.1% MCT increased (p<0.05) ADG and improved (p<0.05) gain:feed ratio for phase 1. Dietary MCT and OA did not affect the fecal score and blood concentration of cortisol, immunoglobulin G, tumor necrosis factor-α, interleukin-1β (IL-1β), IL-6, and IL-10 in weaning pigs. Pigs fed the diets with 0.1% MCT had greater (p<0.05) villus height of duodenum and ileum for phase 1. Also, pigs fed the diet with 0.1% OA showed greater (p<0.05) villus height and villus height to crypt depth ratio of duodenum for phase 2. There was no significant difference in nutrient digestibility and nitrogen retention of pigs. Conclusion: Addition of 0.1% MCT with 0.1% OA in weaning pig's diet improved growth performance partly by enhancing intestinal morphology in weaning pigs.

• 한국안전학회지
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• 제14권2호
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• pp.3-10
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• 1999

Fatigue crack growth rates in commercial plate of high strength Al 7075-T651 were investigated for the T-L direction in air, water and sea water. In this paper the effect of cyclic load wave-form(trapezoid and triangle) on fatigue crack growth rates in air, water and sea water environments were investigated using standard LEFM testing procedures. It was founded that the fatigue crack growth behaviors were not affected by cyclic load wave-forms. In region II (stable crack growth region), the fatigue crack growth behaviors were insensitive to cyclic load wave-forms and were sensitive to environment i.e. fatigue crack growth behaviors were higher in sea water than in air for all cyclic load wave-form. The result of fractographical morphology in air, water and sea water by SEM showed obvious dimple rupture and typical striation in air, but transgranular fracture surface in water and sea water. The values m are not affected by corrosion environments but C are different values.

• 한국안전학회지
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• 제13권4호
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• pp.113-120
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• 1998

Fatigue crack growth rates(i.e. crack initiation and crack growth of short and long crack) are investigated using commercial plates of high strength Al alloy 7075-T651 for the transverse-longitudinal(T-L) direction in air, water and sea water. Also, the evaluation direct current potential drop(D.C.P.D) method and the fractographical analysis by SEM are carried out. Near threshold region, short crack growth rates were much faster than those of comparable long cracks, and these short crack growth rates actually decrease with increasing crack growth and eventually merge with long crack data. Fatigue crack propagation rates in aggressive media(i.e. sea water) increase noticeably over three times those in air. One of the most significant characters in this phenomenon as a corrosion-fatigue causes an acceleration in crack growth rates. Sea water environment, particularly Cl$^{[-10]}$ solution brings the most detrimental effects to aluminum alloy. The result of fractographical morphology in air, water and sea water by SEM shows obvious dimpled rupture and typical striation in air, but transgranular fracture surface in water and sea water.

• 한국결정성장학회지
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• 제4권1호
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• pp.11-20
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• 1994

분자선에피택시(molecular beam epitaxy)법을 이용하여 GaAs 및 ALGaAs layer를 undoped 반절연(100) GaAs 기판위에 성장하였고, 최적의 성장온도와 성장된 시료에 대한 전기적 및 광학적 특성을 조사 하였다. Undoped GaAs층의 성장에 있어서는 측정결과로 부터 As/Ga의유속비가 약 20, 성장온도가 $570^{\circ}C$일때 12K에서의 Photoluminescence 반폭치(FWHM)가 1.14meV인 결정성이 좋은 시료가 얻어졌으며, p형으로서 carrier 농도가 $1.5{\times}10^{14}cm^{-3}$ 미만이고, Hall 이동도가 300K에서 $579cm^2/V-s$인 양질의 에피층이 얻어졌다. 또한 이들 시료에서는 ODLTS, DLTS측정으로 부터 2개의 hole형 깊은 주위만이 관측되었다. Undoped AlGaAs층의 성장에 있어서는 As/(Ga+Al)의 유속비가 20이고 $60^{\circ}C$의 성장온도에서 표면 morphology와 결정성이 좋은 시료를 성장할 수 있었으며, 0.17~0.85eV에서 8개의 깊은 준위가 관측되엇다. Si이 도핑된 AlGaAs 층의 경우, PL 스펙트럼으로 부터 Si의 도핑효과를 관측할 수 있었으며, Hall 측정으로부터 300K에서 $1.5{\times}10^{16}cm^{-3}$일 때 Hall 이동도가 $2547cm^2/V-s$인 시료를 얻을 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제28권12호
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• pp.1742-1750
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• 2015

As a novel approach for disease control and prevention, nutritional modulation of the intestinal health has been proved. However, It is still unknown whether branched-chain amino acid (BCAA) is needed to maintain intestinal immune-related function. The objective of this study was to determine whether BCAA supplementation in protein restricted diet affects growth performance, intestinal barrier function and modulates post-weaning gut disorders. One hundred and eight weaned piglets ($7.96{\pm}0.26kg$) were randomly fed one of the three diets including a control diet (21% crude protein [CP], CON), a protein restricted diet (17% CP, PR) and a BCAA diet (BCAA supplementation in the PR diet) for 14 d. The growth performance, plasma amino acid concentrations, small intestinal morphology and intestinal immunoglobulins were tested. First, average daily gain (ADG) (p<0.05) and average daily feed intake (ADFI) (p<0.05) of weaned pigs in PR group were lower, while gain:feed ratio was lower than the CON group (p<0.05). Compared with PR group, BCAA group improved ADG (p<0.05), ADFI (p<0.05) and feed:gain ratio (p<0.05) of piglets. The growth performance data between CON and BCAA groups was not different (p>0.05). The PR and BCAA treatments had a higher (p<0.05) plasma concentration of methionine and threonine than the CON treatment. The level of some essential and functional amino acids (such as arginine, phenylalanine, histidine, glutamine etc.) in plasma of the PR group was lower (p<0.05) than that of the CON group. Compared with CON group, BCAA supplementation significantly increased BCAA concentrations (p<0.01) and decreased urea concentration (p<0.01) in pig plasma indicating that the efficiency of dietary nitrogen utilization was increased. Compared with CON group, the small intestine of piglets fed PR diet showed villous atrophy, increasing of intra-epithelial lymphocytes (IELs) number (p<0.05) and declining of the immunoglobulin concentration, including jejunal immunoglobulin A (IgA) (p = 0.04), secreted IgA (sIgA) (p = 0.03) and immunoglobulin M (p = 0.08), and ileal IgA (p = 0.01) and immunoglobulin G (p = 0.08). The BCAA supplementation increased villous height in the duodenum (p<0.01), reversed the trend of an increasing IELs number. Notably, BCAA supplementation increased levels of jejunal and ileal immunoglobulin mentioned above. In conclusion, BCAA supplementation to protein restricted diet improved intestinal immune defense function by protecting villous morphology and by increasing levels of intestinal immunoglobulins in weaned piglets. Our finding has the important implication that BCAA may be used to reduce the negative effects of a protein restricted diet on growth performance and intestinal immunity in weaned piglets.

• 한국전기전자재료학회논문지
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• 제18권6호
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• pp.527-531
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• 2005

Fully coherent self-assembled InAs quantum dots(QDs) grown on Si (100) substrates by atmospheric pressure metalorganic chemical vapor deposition(APMOCVD) were grown and the effect of growth conditions such as growth rate and growth time on quantum dots' morphology such as densities and sizes was investigated. InAs QDs of 30 - 80 nm in diameters with densities in the range of (0.6 - 1.7) x $10^{10}\;cm^{-2}$ were achieved on Si substrates and InAs layer was changed from 2 dimensional growth to 3 dimensional one at a nominal thickness less than 0.48 ML. This is attributed to the higher ambient pressure of APMOCVD suppressing of In segregation from the 2 dimensional InAs layer. This In segregation looked to disturb the dot formation especially when the growth rate was low so that the dots became less dense and bigger as the growth rate was lower.

• The Plant Pathology Journal
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• 제21권2호
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• pp.137-141
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• 2005

The effect of cotton leaf mosaic disease on morphology, yield and fibre characteristics was examined for a susceptible cotton candidate variety CRIS-168. Plants inoculated at most susceptible growth stage (six week) under screen house showed severe mosaic symptoms. There was a significant reduction in plant height and yield. Cotton leaf mosaic disease was found to produce severe effects on plant morphology with 24.1% reduction in plant height, 25% in internode length and 37.5% in number of sympodia on main stem. However no changes were observed against number of monopodial branches per plant. Inoculated plants showed 82% decrease in yield/plant, 80% in number of boll set/ plant, 12.1% in boll weight, 12.8% in lint weight, 10.8% in seed weight, and 6.8% in seed index. Cotton leaf mosaic disease also showed effects on fibre characteristics with 0.8% decrease in GOT and 1.6% in fibre length. In contrast, uniformity ratio, fibre fineness and maturity index was increased by 20.5%, 14.4% and 0.9%, respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제12권4호
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• pp.548-553
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• 1999

An experiment was conducted to study the effects of high dietary copper supplementation on the gastrointestinal tract morphology of broiler chickens. Eighty 3-week-old broiler chicks were divided randomly into eight groups of four dietary treatments and over three week were fed isoenergetic and isonitrogenous diets that contained 0, 100, 250, or 500 mg/kg of supplemental copper from cupric sulfate. The copper supplementation in the broiler diet up to 250 mg/kg did not significantly influence broilers' performance. A high dietary copper supplementation of 500 mg/kg did significantly depress growth and feed conversion in the broilers (p<0.05). Copper supplementation more than 250 mg/kg in the broiler diet significantly influenced the morphology of the GI tract, as shown by severe oral lesions and gizzard erosion. It also significantly depressed the villi height and significantly thickened the muscular layer in the duodenum (p<0.05). The severely damaged villi were observed by scanning electronic microscope from the duodenum samples of broilers fed a 500 mg/kg copper supplemented diet. The 500 mg/kg copper supplemented diet also significantly influenced the plasma constituents. Plasma glucose concentration was significantly depressed (p<0.05).

• 대한의생명과학회지
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• 제10권3호
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• pp.293-298
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• 2004

This study was performed to compare the growth rates, cellular fatty acid compositions and morphology by using electron microscope of Escherichia coli (E. coli) grown in various conditions including different concentrations of phenol, CdCl₂ and HgCl₂. Ninety eight E. coli strains were isolated from Naktong river and human feces. The content of unsaturated fatty acids, especially 16:1ω7c and 18:1ωc increased as the concentration of phenol and CdCl₂ increased. The content of unsaturated fatty acid increased up to 50 ppb of HgCl₂, but decreased at 75 ppb of HgCl₂. There were more unsaturated fatty acids than saturated fatty acid in the presence of toxic substances. However, the ration was reversed when the affected E. coli was transferred to toxic substance free fresh trypticase soy broth medium. Also, by using transmission electron microscope these cells were observed to various morphological deformation by heavy metals and their deposition on the surface. From these results, we suggested that the changes of major fatty acids composition and morphology of E. coli may be considered to indicate contaminated levels of heavy metals or organic solvents. The information presented here may be useful in predicting effects of heavy-metal and organic solvent contamination in streams and provides a basis for further studies of metal or organic solvent effects on microbial communities.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.35.1-35.1
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• 2009

Vertically aligned zinc oxide (ZnO) nanorods (NRs) with different surface morphology were grown by metal organic chemical vapor deposition (MOCVD) on sapphire substrate. The films thus prepared were characterized by measuring X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) studies. To study the effect of surface morphology on wettability, the contact angle (CA) of water was measured. It was demonstrated that the CA of the deposited ZnO NRs varied between $104^{\circ}$ and $135^{\circ}$ depending upon the surface morphology. Variable temperature photoluminescence (PL) have employed to probe the exciton recombination in high density and vertically aligned ZnO Nanorod arrays. The low-temperature PL characterizes the dominant near-band-edge excitonic emissions from such nanorod arrays.