• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.437-443
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• 2010

To be economically profitable, the poultry industry demands an increase in stocking density, which could adversely affect chicken welfare. The current study was performed to investigate the effect of stocking density on stress-related, heat shock protein genes (HSP70 and HSP90), 3-hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) gene and telomere length in broiler chickens. Seven-day-old broiler chickens were housed at High (0.0578 $m^2$/bird), Standard (0.077 $m^2$/bird) and Low (0.116 $m^2$/bird) stocking densities with 8 replicates each until 35 d of age. The growth performance, such as body weight gain and average daily feed intake, was found to be significantly (p<0.05) higher in the Low density group, but these parameters did not show any difference between the High and Standard groups. Other growth performance, such as feed conversion ratio and final feed intake, showed no difference among the treated groups. The expression levels of HSP70 and HMGCR were found to be elevated with the increase of stocking density. The expression level of these genes was significantly (p<0.05) higher in the High density stocked group compared with the other groups, whereas the expression levels were not significantly different between the Low and Standard groups. The expression levels of HSP90 did not show any significant changes among the treated groups. The telomeric length of the birds housed in High density was reduced significantly (p<0.05) when compared to that of the birds in Low density. These results clearly indicate that birds stocked at high density show physiological adaptive changes indicative of stress at gene transcriptional and telomere levels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.95-99
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• 2001

Soybean [Glycine max (L.) Merr.) is known to produce the highest total digestible mutrients (TDN) yield among summer grain legumes in Jeju area but little is known about the effects of cultural practices on forage yield and quality. A determinate soybean cv. Baegunkong was planted on 5 June, 20 June, and 3 July and grown at four plant densities (30, 50, 70 and 90 plants $m^{-2}$ in 1998 in Jeju to evaluate the effects of planting date and plant density on the yield and quality of soybean forage. Days to flowering decreased from 47 to 38 days, average plant height from 61 to 51cm and main stem diameter from 6.31 to 5.00mm as planting was delayed from 5 June to 3 July. Average plant height quadratically increased from 45 to 62cm as plant density increased from 30 to 90 plants $m^{-2}$. Planting date did not affect the average dry matter, crude protein, and TDN yields. The average dry matter and TDN yields displayed a quadratic response to plant density and the optimum plant density for both dry matter and TDN yields was estimated about 60 plants $m^{-2}$. Plant density had no effect on crude protein yield. Planting date did not significantly influence forage quality. The crude protein content was not significantly influenced by plant density. Increasing plant density slightly increased acid detergent fiber content but slightly decreased TDN content.

• Journal of radiological science and technology
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• v.44 no.3
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• pp.211-218
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• 2021

The purpose of this study was to investigate the effect of sex and menopausal age on the thickness and density of squamous portion of the temporal bone as the membranous bone. Patients who visited a general hospital in Chungnam and had a computed tomography (CT) examination of the head. A retrospective study was conducted with 120 subjects (30 men under 55 years old, 30 men over 56 years old, 30 women under 55 years old, and 30 women over 56 years old). Axial images of the squamous portion in the temporal bone were obtained from CT of the head. For this image, a slice sensitive profile (SSP) was acquired with an image analysis program and these were evaluated. The thickness was measured by using a digital ruler to measure the full width at half maximum (FWHM) of the SSP, and the density was measured in hounsfield unit (HU). These by gender were measured to be about 0.5 mm thinner in the temporal bone in men than in women, and there was a significant difference. The density was measured to be about 200 HU higher in women than in men of it, and there was a significant difference. As a result, it in women was thicker and had a lower density. The thickness of it in men and women over 56 years of age was 0.8 mm or more thicker in women and less than 400 HU in density. As a result, the women group over the age of 56 showed a distinct increase in thickness and decrease in density, different from other target groups. It is expected that the results of this study could be used as basic data for a new bone density measurement site study.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.19-24
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• 2004

Entrainment of ambient gas into a transient diesel spray is a crucial factor affecting the following preparation of combustible mixture. In this study, the entrainment characteristics of ambient gas for a non-evaporating transient diesel were investigated using a common-rail injection system. The effects of ambient gas density and nozzle hole geometry were assessed with entrainment coefficient. Laser Doppler Velocimetry (LDV) technique was introduced to measure the entrainment speed of ambient gas into a spray. There appeared a region where the entrainment coefficients remained almost constant while injection rates were still changing. The effect of common-rail pressure, which altered the slope of injection rate curve, was hardly noticed at this region. Entrainment coefficient increased with ambient gas density, that is, the effect of ambient gas density was greater than that of turbulent jet whose entrainment coefficient remained constant. The non-dimensional distance was defined to reflect the effect of nozzle hole diameter and ambient gas density together. The mean value of entrainment coefficient was found to increase with non-dimensional distance from the nozzle tip, which would be suggested as the guideline for the nozzle design.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.240-244
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• 1993

Yacon(Polymina sonchifolia POEPP), an indigenous Andean natural resource food plant, was imported as a new root crop from New Zealand in 1986. However the chemical composition and planting system of it have not been research in Korea. The experimental results for the optimum planting densities and mulching effect are as follows. Height of the main stem of yacon was grown linear from July to October, is showed more fast growth as density increased, and showed highest in 70 ${\times}$ 55cm density. The tiller was bubed 3 month after planting but there was no significant difference among mulching, non-mulching condition and planting density. The fresh weight of root of mulching condition was heavier than that in non-mulching condition and 70 ${\times}$ 40cm mulching condition. In mulching treatment, number of roots in dense planting were more than that in sparse planting. The effect of mulching was not shown significantly in root diameter and root length.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.1014-1021
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• 1998

We evaluated the effect of processing variables on microstructural evolution interface irregularity between Ag sheath and superconductor core and resultant critical current density(J$_{c}$) of (Bi,Pb)$_2$Sr$_2$Ca$_2$Cu$_3$O$_{x}$(2223) superconductor tape. The value of J$_{c}$ was significantly influenced by the interface irregularity, degree of texturing and relative 2223 content. The interface became more irregular(sausage effect), while the degree of texturing gradually improved as the dimension of tape decreased during forming process. As the dimension of wire/tape were changed from diameter of 3.25 mm to thickness of 0.20 mm, J$_{c}$ value was observed to be increased by 10 times. In addition, optimum sintering temperature for improved J$_{c}$ was observed to be 835$^{\circ}C$ in a ambient atmosphere probably due to combined effect of both improved texturing and high 2223 content. Microstructural investigation showed the degree of texturing was degraded by the existence of both second phases and interface irregularity. It was observed that larger grain size and better texturing was developed near relatively flat interface compared to those inside superconducting core.ting core.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.2 s.110
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• pp.11-20
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• 2005

This study was carried out to investigate the influence of paper stock type and heat treatment on sizing effect. Various types of pulps were used to make handsheets sized internally with AKD(alkyl ketene dimer) and externally with CMC(carboxyl methyl cellulose). Most of the handsheets were treated with heat by dry oven $(100^{\circ}C,\;30min)$ to evaluate the effect of heat treatment on sizing development. Internal sizing development of newsprint was very bad, but the effect of heat treatment was much higher than those of NBKP, BCTMP. In case of surface sizing, newsprint was more effective compared to the other pulps. Considering above mentioned results, it seems that internal sizing slows down water into paper by molecular diffusion much more than capillary penetration, but surface sizing slows down capillary penetration. With regard to density, a higher thickness sheets showed high heat treatment effect on sizing, therefore it assumed that heat treatment effect on sizing had very close relationship with sheet density.

• Journal of Nutrition and Health
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• v.37 no.2
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• pp.100-107
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• 2004

This study was performed to evaluate the effect of dietary protein source and sulfur amino acid content on bone metabolism in ra. Thirty male rats (body weight 145$\pm$2g) were divided into three groups. The rats in the first group were fed on casein 20% diet as animal protein source and those in the second group were fed on soy 20% diet as plant protein source. Sulfur amino acid ratio of these group was 1.07:1. The rats in the third group were fed on soy 20% diet and the sulfur amino acid were supplemented with the amount contained as much in the soy 20% diet. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks, The total body, spine, femur bone mineral density and bone mineral content were measured using Dual Energy X-ray Absorptiometry Calcium, phosphate, pyridinoline, creatinine in urine and calcium, phosphate, alkaline phosphatase, osteocalcin in serum were measured. During the experimental period, plant protein (soy protein) group had a lower urinary Ca excretion, urine pyridinoline ＆ crosslinks value and had a higher Ca efficiency in total bone and femur bone mineral density than animal protein (casein) group. There were no significant differences in serum calcium, phosphate, alkaline phosphatase and osteocalcin among the three groups of the rats. The findings from this study demonstrated that plant protein (soy protein) is beneficial of bone mineral density because it had a higher Ca efficiency in total bone and femur bone mineral density than animal protein (casein). However, the supplementation of sulfur amino acid on soy results were consistent with prior studies that dietary sulfur amino acid load had a negative effect on calcium balance. The rats fed sulfur amino acid supplementation diet increased urinary calcium excretion and decreased calcium efficiency for total and femur mineral density. Therefore, dietary protein source and sulfur amino acid content influence bone metabolism. (Korean J Nutrition 37(2): 100-107, 2004)

• Progress in Medical Physics
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• v.32 no.4
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• pp.165-171
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• 2021

Purpose: This study aimed to evaluate the effect of collimator width on effective atomic number (EAN), relative electron density (RED), and stopping power ratio (SPR) measured by dual-layer dual-energy computed tomography (DL-DECT). Methods: CIRS electron density calibration phantoms with two different arrangements of material plugs were scanned by DL-DECT with two different collimator widths. The first phantom included two dense bone plugs, while the second excluded dense bone plugs. The collimator widths selected were 64 mm×0.625 mm for wider collimators and 16 mm×0.625 mm for narrow collimators. The scanning parameters were 120 kVp, 0.33 second gantry rotation, 3 mm slice thickness, B reconstruction filter, and spectral level 4. An image analysis portal system provided by a computed tomography (CT) manufacturer was used to derive the EAN and RED of the phantoms from the combination of low energy and high energy CT images. The EAN and RED were compared between the images scanned using the two different collimation widths. Results: The CT images with the wider collimation width generated more severe artifacts, particularly with high-density material (i.e., dense bone). RED and EAN for tissues (excluding lung and bones) with the wider collimation width showed significant relative differences compared to the theoretical value (4.5% for RED and 20.6% for EAN), while those with the narrow collimation width were closer to the theoretical value of each material (2.2% for EAN and 2.3% for RED). Scanning with narrow collimation width increased the accuracy of SPR estimation even with high-density bone plugs in the phantom. Conclusions: The effect of CT collimation width on EAN, RED, and SPR measured by DL-DECT was evaluated. In order to improve the accuracy of the measured EAN, RED, and SPR by DL-DECT, CT scanning should be performed using narrow collimation widths.

• Transactions of Materials Processing
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• v.6 no.6
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• pp.508-516
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• 1997

Forging process on sintered powder metals has been applied to produce automotive parts which require a high level of strength. In those parts, the measurement of relative density is very important because a low relative density density causes deterioration of strength. In the present study, an indentation force equation was proposed by which the result obtained from the hardness measurement is used to evaluate the relative density. This equation was applied to the prediction of the relative density in cylindrical specimens which were first sintered and then forged at the room temperature and at an elevated temperature. The experimental results were compared with predictions with and without consideration of the workhardening effect on the powder.