• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.57-63
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• 2024

As global warming worsens, it is feared that higher ambient temperatures and relative humidity might result in a more intense heat stress for livestock animals, especially broilers, which lack sweat glands for thermoregulation and have been selectively bred for rapid growth. Therefore, strategic livestock management is needed to mitigate the adverse effects of heat stress on broilers. In Korea's poultry farming systems, tunnel-ventilated broiler houses and pad cooling systems are commonly installed to lower indoor temperatures during the summer. However, caution is advised with pad cooling systems as they can increase the humidity inside the houses, potentially causing further harm. This study aimed to evaluate the effectiveness of pad cooling systems in tunnel-ventilated broiler house by assessing the reduction in indoor temperature using the Temperature-Humidity Index (THI), which accounts for the impact of relative humidity. Temperature and humidity data were collected during the summer (Jun to Sep) from eight farms with tunnel-ventilated broiler house located in different regions of Korea. The farms were divided into two groups based on the use of pad cooling systems is used, and temperature and humidity data, along with THI values, were analyzed two weeks before the birds were marketed. Meta-analysis results showed that at the hottest time of the day, 14:00, farms with pad cooling systems had significantly lower indoor temperatures compared to the control group, but observed an increase in indoor temperatures by 16:00 (p<0.05). There is no significant difference in relative humidity (p>0.05). The THI values decreased in the treatment group with cooling pads compared to the control group starting from 15:00, suggesting a diminished effect (p<0.05). This study indicates the potential for developing optimal operational guidelines for cooling pads to reduce heat stress in broilers during the summer season.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.257-267
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• 2017

Background: Heat-processed ginseng, sun ginseng (SG), has been reported to have improved therapeutic properties compared with raw forms, such as increased antidiabetic, anti-inflammatory, and antihyperglycemic effects. The aim of this study was to investigate the antiobesity effects of SG through the suppression of cell differentiation and proliferation of mouse 3T3-L1 preadipocyte cells and the lipid accumulation in Caenorhabditis elegans. Methods: To investigate the effect of SG on adipocyte differentiation, levels of stained intracellular lipid droplets were quantified by measuring the oil red O signal in the lipid extracts of cells on differentiation Day 7. To study the effect of SG on fat accumulation in C. elegans, L4 stage worms were cultured on an Escherichia coli OP50 diet supplemented with $10{\mu}g/mL$ of SG, followed by Nile red staining. To determine the effect of SG on gene expression of lipid and glucose metabolism-regulation molecules, messenger RNA (mRNA) levels of genes were analyzed by real-time reverse transcription-polymerase chain reaction analysis. In addition, the phosphorylation of Akt was examined by Western blotting. Results: SG suppressed the differentiation of 3T3-L1 cells stimulated by a mixture of 3-isobutyl-1-methylxanthine, dexamethasone, and insulin (MDI), and inhibited the proliferation of adipocytes during differentiation. Treatment of C. elegans with SG showed reductions in lipid accumulation by Nile red staining, thus directly demonstrating an antiobesity effect for SG. Furthermore, SG treatment down-regulated mRNA and protein expression levels of peroxisome proliferator-activated receptor subtype ${\gamma}$ ($PPAR{\gamma}$) and CCAAT/enhancer-binding protein-alpha ($C/EBP{\alpha}$) and decreased the mRNA level of sterol regulatory element-binding protein 1c in MDI-treated adipocytes in a dose-dependent manner. In differentiated 3T3-L1 cells, mRNA expression levels of lipid metabolism-regulating factors, such as amplifying mouse fatty acid-binding protein 2, leptin, lipoprotein lipase, fatty acid transporter protein 1, fatty acid synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase, were increased, whereas that of the lipolytic enzyme carnitine palmitoyltransferase-1 was decreased. Our data demonstrate that SG inversely regulated the expression of these genes in differentiated adipocytes. SG induced increases in the mRNA expression of glycolytic enzymes such as glucokinase and pyruvate kinase, and a decrease in the mRNA level of the glycogenic enzyme phosphoenol pyruvate carboxylase. In addition, mRNA levels of the glucose transporters GLUT1, GLUT4, and insulin receptor substrate-1 were elevated by MDI stimulation, whereas SG dose-dependently inhibited the expression of these genes in differentiated adipocytes. SG also inhibited the phosphorylation of Akt (Ser473) at an early phase of MDI stimulation. Intracellular nitric oxide (NO) production and endothelial nitric oxide synthase mRNA levels were markedly decreased by MDI stimulation and recovered by SG treatment of adipocytes. Conclusion: Our results suggest that SG effectively inhibits adipocyte proliferation and differentiation through the downregulation of $PPAR{\gamma}$ and $C/EBP{\alpha}$, by suppressing Akt (Ser473) phosphorylation and enhancing NO production. These results provide strong evidence to support the development of SG for antiobesity treatment.

• Journal of the Korean Vacuum Society
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• v.22 no.2
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• pp.55-65
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• 2013

Sterilization of Neurospora crassa has been investigated in this research by using a surface air plasma with dielectric barrier discharged (DBD) structure under atmospheric pressure. The sinusoidal alternating current has been used in this experiment with discharge voltage of 1.4~2.3 kV. The phase difference between the voltage and current signals are found to be almost 80 degree due to the capacitive property of dielectric barrier. Temperature on the biomaterials has been minimized by radiating the heat with the air cooling system. It is noted that the substrate temperature remains under 37 degree for plasma exposure time of 10 minutes with operation of cooler system. It is found that the ozone, $O_3$, has been measured to be about 25~30 ppm within 1 cm region and to be about 5 ppm at the 150 cm downstream region away from the suface plasma. It is also noted that the nitric oxide, NO, and nitric dioxide, $NO_2$, are not nearly detected. Germination rate and mitochodrial activity of Neurospora crassa immersed in the deionized water have been found to be drastically decreased as the plasma treatment time and its electrical power are increased in this experiment. Here, the mitochondrial activity has been analyzed by MTT (3-(4,5-dimethy lthiazol-2yl)-2,5-diphenyl-2H-tetrazolium bromide) assay. However, sterilization of Neurospora crassa immersed in the Vogel's minimal media has been found to be low by plasma treatment, which is caused by surrounding background solution. This research shows the sterilization possibility of Neurospora crassa by using the noncontated surface DBD plasma, which is different from the plasma jet. This is mainly attibuted to the reactive species generated by the surface plasma, since they play a major role for inhibition of micobes such as Neurospora crassa.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.235-243
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• 2007

Hepatocellular carcinoma is significant worldwide public health problem with an estimated annually mortality of 1,000,000 people. Radiofrequency (RF) ablation is an interventional technique that in recent years has come to be used for treatment of the hepatocellualr carcinoma, by destructing tumor tissues in high temperatures. Numerous studies have been attempted to prove excellence of RF ablation and to improve its efficiency by various methods. However, the attempts are sometimes paradox to advantages of a minimum invasive characteristic and an operative simplicity in RF ablation. The aim of the current study is, therefore, to suggest an improved RF ablation technique by identifying an optimum RF pattern, which is one of important factors capable of controlling the extent of high temperature region in lossless of the advantages of RF ablation. Three-dimensional finite element (FE) model was developed and validated comparing with the results reported by literature. Four representative Rf patterns (sine, square, exponential, and simulated RF waves), which were corresponding to currents fed during simulated RF ablation, were investigated. Following parameters for each RF pattern were analyzed to identify which is the most optimum in eliminating effectively tumor tissues. 1) maximum temperature, 2) a degree of alteration of maximum temperature in a constant time range (30-40 second), 3) a domain of temperature over $47^{\circ}C$ isothermal temperature (IT), and 4) a domain inducing over 63% cell damage. Here, heat transfer characteristics within the tissues were determined by Bioheat Governing Equation. Developed FE model showed 90-95% accuracy approximately in prediction of maximum temperature and domain of interests achieved during RF ablation. Maximum temperatures for sine, square, exponential, and simulated RF waves were $69.0^{\circ}C,\;66.9^{\circ}C,\;65.4^{\circ}C,\;and\;51.8^{\circ}C$, respectively. While the maximum temperatures were decreased in the constant time range, average time intervals for sine, square, exponential, and simulated RE waves were $0.49{\pm}0.14,\;1.00{\pm}0.00,\;1.65{\pm}0.02,\;and\;1.66{\pm}0.02$ seconds, respectively. Average magnitudes of the decreased maximum temperatures in the time range were $0.45{\pm}0.15^{\circ}C$ for sine wave, $1.93{\pm}0.02^{\circ}C$ for square wave, $2.94{\pm}0.05^{\circ}C$ for exponential wave, and $1.53{\pm}0.06^{\circ}C$ for simulated RF wave. Volumes of temperature domain over $47^{\circ}C$ IT for sine, square, exponential, and simulated RF waves were 1480mm3, 1440mm3, 1380mm3, and 395mm3, respectively. Volumes inducing over 63% cell damage for sine, square, exponential, and simulated RF waves were 114mm3, 62mm3, 17mm3, and 0mm3, respectively. These results support that applying sine wave during RF ablation may be generally the most optimum in destructing effectively tumor tissues, compared with other RF patterns.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.158-165
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• 2018

The effects of different kinds of supplementary lighting or heating lamps on the yield, cut flower life, and leaf color of cut rose were compared and analyzed. For this purpose, light emitting diode lamp (LED), metal halide lamps (MH), and high-pressure sodium lamps (HPS) as the supplementary lamps, and carbon fiber infrared lamp (NCFI) were installed on hydroponic cultivation bed in a cut rose farm. The yield of cut flower rose and the number of marketable flowers were greatly increased in spring and autumn by HPS treatment, but not in winter. The length of flower stalk was longer than that of control in the spring but decreased in winter. It seemed likely that the shorter flower stalk in winter was due to the shortened period of vegetative growth compared to the control because flowering was promoted by supplementary lighting. Vase life was not different among treatments in the autumn when the lighting time was short, but in winter, it was prolonged to 3 more days by only HPS, compared with the control. Leaf color was significantly affected by light treatment in winter rather than autumn. Leaf color was darkened in all supplementary lamps (LED, MH, HPS) treatment, whereas NCFI was similar to the control in leaf color. In conclusion, HPS is considered to be a very good supplementary lamp because it increases the length of flower stalk and the yield and prolongs vase life in cut roses. Even though NCFI could function as a heating lamp radiating a lot of heat, it was considered that the role as a supplementary light is unsatisfactory because the number of marketable flowers decreases and the quality index of cut rose deteriorates by NCFI.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.3
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• pp.157-170
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• 2002

The purpose of this study is to analyze the shear bond strength according to kinds of surface treatment agents and resin cements after acid etching of IPS Empress 2. For this purpose, test groups were classified into silane-treated bonding groups, silica-coated group and Targis link applied group. Then, nine bonding groups in total, each three groups per kind, were prepared by using three kinds of resin cements-Panavia F, Variolink II and Rely-X ARC, and thirty test specimens per group were prepared. To examine any changes in the oral environment, the shear bond strength of each test specimen was measured after dipping test for 24 hours and for five weeks, respectively, in distilled water at $37^{\circ}C$ and performing heat cycle 10,000 times in total, each 2,000 times per week, during a five weeks of dipping, under the condition similar to the oral environment. The bond failure modes were also observed by means of a scanning electron microscope. The results are summarized as follows 1. Statically significant differences between the surface conditioning materials were observed. The shear strength of the silane treatment was the highest of all three types of surface treatments(p<0.001). 2. Shear strengths varied significantly for different types of resin luting agents. But bond strength of Targis link surface treatments were not significantly different(p<0.05). 3. No significant difference of bonding strengths was found between storage time conditions(24 hours and 5 weeks). Only group II, IV, VII, IX were significantly different(p<0.05). 4. After thermocycling, the shear bond strengths of all groups were significantly decreased (p<0.05). Group III, V, VI were no significantly different. 5. On the SEM observation of fractured surfaces, all groups were shown complex failure.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.870-876
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• 1994

In order to investigate the growth behavior of $Y_{2}Ba_{1}Cu_{1}O_{5}$(211) particles in $Y_{1}Ba_{2}Cu_{3}O_{7-\delta}$(123), 123 samples were quenched in air after heat treatment on polycrystal and single crystal MgO substrates at $1100^{\circ}C$ for various periods. 211 grains grew with the increase in holding time. The growth of 211 grains was faster on the polycrystal MgO substrate than on the single crystal MgO substrate. In the samples with the compositions of 211+xCuO($0.2\le X \le 0.8$), the growth rate of 211 grains increased with the increase in CuO content. In the sample with x=0.6 the largest 211 grains were observed. 211 grains in the $Y_{2}Ba_{1}Cu_{1.8}Sn_{0.1}O_{5+\delta}$ samples were distributed very finely and homogeneously. The retarding effect of $SnO_2$ addition on the growth of 211 grain appeared more pronounced in a CuO melt than in a $BaCuO_{2}$+ CuO melt.

• Journal of the Korean Chemical Society
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• v.48 no.4
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• pp.371-378
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• 2004

The $SrGa_2S_4:Eu^{2+}$ green emitting phosphor has been studied as a luminous device for CRT (Cathode Ray Tube) or FED (Field Emission Display) and EL (Electroluminescence). This phosphor, also, is under noticed for LED (Lighting Emitting Diode) phosphor, which makes use of excitation characteristics of long wavelength region. The $SrGa_2S_4:Eu^{2+}$ phosphor was prepared generally conventional synthesis method using flux. However, this method needs high heat-treated temperature, long reaction time, complex process and harmful $H_2S$or $CS_2$ gas. In this works, therefore, we have synthesized $SrGa_2S_4:Eu^{2+}$ using SrS, $Ga_2S_3$, and EuS as starting materials, and the mixture gas of 5% H2/95% N2 was used to avoid the $H_2S$or $CS_2$. We investigated the luminescence characteristic of $SrGa_2S_4:Eu^{2+}$ phosphor prepared in various synthesis conditions, performed post-treatment and sieving process for application to LED.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.6
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• pp.245-251
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• 2015

We have applied mechanical alloying (MA) to produce soft magnetic composite material using a mixture of elemental $Fe_2O_3$-Mg powders. An optimal milling and heat treatment conditions to obtain soft magnetic ${\alpha}$-Fe/MgO composite with fine microstructure were investigated by X-ray diffraction, differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM) measurement. It is found that ${\alpha}$-Fe/MgO composite powders in which MgO is dispersed in ${\alpha}$-Fe matrix are obtained by MA of $Fe_2O_3$ with Mg for 30 min. The saturation magnetization of ball-milled powders increases with increasing milling time and reaches to a maximum value of 69.5 emu/g after 5 h MA. The magnetic hardening due to the reduction of the ${\alpha}$-Fe grain size by MA was also observed. Densification of the MA powders was performed in a spark plasma sintering (SPS) machine at $800{\sim}1000^{\circ}C$ under 60 MPa. X-ray diffraction result shows that the average grain size of ${\alpha}$-Fe in ${\alpha}$-Fe/MgO nanocomposite sintered at $800^{\circ}C$ is in the range of 110 nm.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.772-777
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• 1999

$Y_2Ba_1Cu_1O_5(Y211)$ powders were prepared by pyrophoric synthesis method and by solid state reaction method using $Y_2O_3(99.9%)$, $BaCO_3(99.9%)$, and CuO(99.9%) powders in both of these processes. The phase formation and reaction kinetics of $Y_2Ba_1Cu_1O_5$ powders have been studied using X-ray diffraction analysis(XRD) of samples at various heat treatment temperatures and reaction time. The reaction characterization suggested that the phase formation rate is mainly controlled by the particle size of Y211 powders. The activation energy(${\Delta}E_a$) of Y211 phase formation in this pyrophoric synthesis method was found to be 136.42 kJ/mol compared with 149.46 kJ/mol for that of solid state reaction method. These results data showed that the pyrophoric synthesis method is kineticaly more efficient than the solid state reaction method in this $Y_2Ba_1Cu_1O_5$ system.