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A Study on the Determination of Scan Speed in Whole Body Bone Scan Applying Oncoflash (Oncoflash를 적용한 전신 뼈 영상 검사의 스캔 속도 결정에 관한 연구)

  • Yang, Gwang-Gil;Jung, Woo-Young
    • The Korean Journal of Nuclear Medicine Technology
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    • v.13 no.3
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    • pp.56-60
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    • 2009
  • Purpose: The various studies and efforts to develop program are in progress in the field of nuclear medicine for the purpose of reducing scan time. The Oncoflash is one of the programs used in whole body bone scan which allows to maintain the image quality while to reduce scan time. When Those applications are used in clinical setting, both the image quality and reduction of scan time should be considered, therefore, the purpose of this study was to determine the criteria for proper scan speed. Materials and Methods: The subjects of this study were the patients who underwent whole body bone scan at the departments of nuclear medicine in the Asan Medical Center located in Seoul from 1st to 10th, July, 2008. The whole body bone images obtained in the scan speed of 30cm/min were classified by the total counts into under 800 K, and over 800 K, 900 K, 1,000 K, 1,500 K, and 2,000 K. The image quality were assessed qualitatively and the percentages of those of 1,000K and under of total counts were calculated. The FWHM before and after applying the Oncoflash were analyzed using images obtained in $^{99m}Tc$ Flood and 4-Quadrant bar phantom in order to compare the resolution according to the amount of total counts by the application of the Oncoflash. Considering the counts of the whole body bone scan, the dosed 2~5 mCi were used. 152 patients underwent the measurement in which the counts of Patient Postioning Monitor (PPM) were measured with including head and the parts of chest which the starting point of whole body bone scan from 7th to 26th, August, 2008. The correlations with total counts obtained in the scan speed of 30cm/min among them were analyzed (The exclusion criteria were after over six hours of applying isotopes or low amount of doses). Results: The percentage of the whole body bone image which has the geometric average of total counts of under 1,000K among them obtained in the scan speed of 30cm/min were 17.6%(n=58) of 329 patients. The qualitative analysis of the image groups according to the whole body counts showed that the images of under 1,000K were assessed to have coarse particles and increased noises. The analysis on the FWHM of the images before and after applying the Oncoflash showed that, in the case of PPM counts of under 3.6 K, FWHM values after applying the Oncoflash were higher than that before applying the Oncoflash, whereas, in the case of that of over 3.6 K, the FWHM after applying the Oncoflash were not higher than that before applying the Oncoflash. The average of total counts at 2.5~3.0 K, 3.1~3.5 K, 3.6~4.0 k, 4.1~4.5 K, 4.6~5.0 K, 5.1~6.0 K, 6.1~7.0 K, and 7.1 K over (in PPM) were $965{\pm}173\;K$, $1084{\pm}154\;K$, $1242{\pm}186\;K$, $1359{\pm}170\;K$, $1405{\pm}184\;K$, $1640{\pm}376\;K$, $1,771{\pm}324\;K$, and $1,972{\pm}385\;K$, respectively and the correlations between the counts in PPM and the total counts of image obtained in the scan speed of 30 cm/min demonstrated strong correlation (r=.775, p<.01). Conclusions: In the case of PPM coefficient over 3.6 K, the image quality obtained in the scan speed of 30cm/min and after applying the Oncoflash was similar to that obtained in the scan speed of 15 cm/min. In the case of total counts over 1,000 K, it is expected to reduce scan time without any damage on the image quality. In the case of total counts under 1,000 K, however, the image quality were decreased even though the Oncoflash is applied, so it is recommended to perform the re-image in the scan speed of 15 cm/min.

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A Therapeutic Effect of Ozonated Oil on Bovine Mastitis (젖소 유방염에 대한 Ozonated oil의 치료효과)

  • Jo Sung-Nam;Liu Jianzhu;Lee Sang-Eun;Hong Min-Sung;Kim Duck-Hwan;Kim Myung-Cheol;Cho Sung-Whan;Jun Moo-Hyung
    • Journal of Veterinary Clinics
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    • v.22 no.4
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    • pp.318-321
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    • 2005
  • Forty- nine quarters from 24 lactating cows with chronic mastitis were selected. The cows were raised on dairy farms in Gongju, Jochiwon and Yeongi in Chungnam province, and Iksan in Jeonbuk province, Korea. The 49 quarters with bovine mastitis were divided into control (7 quarters) and experimental (42 quarters) groups. The experimental quarters were assigned to experimental group A (10 quarters, somatic cell count: $50-100\times10^4/ml)$, experimental group B (14 quarters, somatic cells count: $100-300{\times}10^4/ml)$, and experimental group C (18 quarters, somatic cells count: $>300\times10^4/ml$), according to the number of the somatic cells in their milk. The quarters of control group were treated with norfloxacin ointment (10 g/tube) based on the result of sensitivity, twice a day for 3 days. The quarters or experimental groups were infused 10ml or ozonated oils twice a day for 3 days. After treatment, the milk of the control group contained non-significantly lower numbers of somatic cells and bacteria on day 7, compared with pretreatment levels. Experimental groups A, B and C had lower somatic and bacterial cells in their milk on day 7, compared with pretreatment levels. Experimental group B and C had significantly lower numbers of somatic cells in their milk ell day 7 than before treatment (p<0.01). However, no significant difference in somatic cell numbers was detected between the control alld experimental groups. It was concluded that ozone therapy with ozonated oil applied on bovine mastitis might be effective.

Breathing Reserve Index at Anaerobic Threshold of Cardiopulmonary Exercise Test in Chronic Obstructive Pulmonary Disease (만성폐쇄성 폐질환의 운동부하 심폐기능검사에서 무산소역치 예비호흡지수의 의의)

  • Lee, Byoung-Hoon;Kang, Soon-Bock;Park, Sung-Jin;Jee, Hyun-Suk;Choi, Jae-Chol;Park, Yong-Bum;Ahn, Chang-Hyuk;Kim, Jae-Yeol;Park, In-Won;Choi, Byung-Whui;Hue, Sung-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.46 no.6
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    • pp.795-802
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    • 1999
  • Objective : Cardiopulmonary exercise test is a useful tool to evaluate the operative risk and to plan exercise treatment for the patients with chronic obstructive pulmonary disease(COPD). In cardiopulmonary exercise test, most of the measured parameters are recorded at the time of peak exercise, which are hard to attain in COPD patients. So we evaluated the usefulness of the parameter, breathing reserve index(BRI=minute ventilation [$V_E$]/maximal voluntary ventilation[MVV]) at the time of anaerobic threshold($BRI_{AT}$) for the differentiation of COPD patients with normal controls. Methods : Thirty-six COPD patients and forty-two healthy subjects underwent progressive, incremental exercise test with bicycle ergometer upto possible maximal exercise. All the parameters was measured by breath by breath method. Results : The maximal oxygen uptake in COPD patients (mean$\pm$SE) was $1061.2{\pm}65.6ml/min$ which was significantly lower than $2137.6{\pm}91.4ml/min$ of normal subjects(p<0.01). Percent predicted maximal oxygen uptake was 54.3% in COPD patients and 86.0% in normal subjects(p<0.01). Maximal exercise(respiratory quotient; $VCO_2/VO_2{\geq}1.09$) was accomplished in 7 of 36 COPD patients(19.4%) and in 18 of 42 normal subjects(42.9%). The $BRI_{AT}$ of COPD patients was higher($0.50{\pm}0.03$) than that of control subject($028{\pm}0.02$, p<0.01), reflecting early hyperventilation in COPD patient during exercise. The correlation between $BRI_{AT}$ and BRI at maximal exercise in COPD patients was good(r=0.9687, p<0.01). Conclusion : The $BRI_{AT}$ could be a useful parameter for the differentiation of COPD patients with normal controls in the submaximal cardiopulmonary exercise test.

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The Effect of Heat Shock Response on the Tumor Necrosis Factor-$\alpha$-induced Acute Lung Injury in Rats (Tumor Necrosis Factor-$\alpha$로 유도되는 백서의 급성 폐손상에 열충격반응이 미치는 효과)

  • Koh, Youn-Suck;Lim, Chae-Man;Kim, Mi-Jung;Cho, Won-Kyung;Jeoung, Byung-O;Song, Kyu-Young;Shim, Tae-Sun;Lee, Sang-Do;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.6
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    • pp.1343-1352
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    • 1997
  • Background : Heat-treated cells are known to be protected from lysis by TNF, which is considered to play a central role in the pathogenesis of sepsis-induced acute lung injury. The objective of the study was to investigate the effect of heat shock response by heat-pretreatment on the acute lung injury of the rats induced by intratracheally administered TNF-$\alpha$, Methods : We intratracheally instilled either saline or TNF (R&D, 500ng) with and without heat pretreatment in Sprague-Dawley rats weighing 250~350 g. The heated rats were raised their rectal temperature to $41^{\circ}C$ and was maintained thereafter for 13 minutes at 18 h before intratracheal administration of saline or TNF. After 5 h of intratracheal treatment, lung leak, lung myeloperoxidase activity (MPO) and heat shock proteins were measured in rats. Lung leak index was defined as counts per minute of $I^{25}$ in the right lung divided by counts per minutes of $I^{25}$ in 1.0 ml of blood. All data are expressed as means ${\pm}$SE. Results : There is no difference in acute lung leak index ($0.099{\pm}0.024$ vs $0.123{\pm}0.005$) among the rats given saline intratracheally with and without heat pretreatment, but MPO activity showed a decreased tendency in heat-pretreated rats ($4.58{\pm}0.79\;U/g$) compared with heat-unpretreated rats ($7.32{\pm}0.97\;U/g$) (P=0.064). Rats administered TNF intratracheally with heat-pretreatment had decreased lung leak index ($0.137{\pm}0.012$) and lung MPO activity ($5.51{\pm}1.04\;U/g$) compared with those of heat-unpretreated and TNF-administered rats ($0.186{\pm}0.016$, $14.34{\pm}1.22\;U/g$) (P<0.05 in each). There were no significant difference of lung leak index and MPO activity between TNF-treated rats with heat-pretreatment and saline-treated rats with and without heat-pretreatment. Conclusion : The heat shock response attenuated neutrophil recruitment and acute lung leak induced by intratracheal instillation of TNF-in rats.

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Studies on the Characteristics of Volatile Fatty Acid Evolution from Fresh Animal Feces (축분의 휘발성 지방산 발현 양상 연구)

  • ;;;Hudson, Neale
    • Journal of Animal Environmental Science
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    • v.10 no.1
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    • pp.11-22
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    • 2004
  • This work was carried out to measure volatile fatty acids emissions from different manure (poultry, swine, cattle) incubated at $10^{\circ}C$, $25^{\circ}C$, and $37^{\circ}C$ for 6 days under anaerobic condition. Following are summary of these tests results. 1. Amounts of Acetic acid generated were 1,128.05mg/kg, 628.21mg/kg and 592.50mg/kg for swine, poultry, and cattle manure, respectively, during the period of incubation. In the case of swine and cattle manure, 83.87%(946.10mg/kg) and 57.49%(340.63mg/kg) from all the temperature treatments were produced in the $25^{\circ}C$, respectively. 83.57% in swine and 78.79% in cattle manure were intensively emerged from 3 day, 4 day and 5 day of the $25^{\circ}C$ treatment. In the case of poultry manure, 45.36%(284.93mg/kg) and 45.36%(284.93mg/kg) in the $25^{\circ}C$ and in the $37^{\circ}C$, respectively, were produced. Accordingly, acetic acid generated from poultry manure was characteristic of being mainly produced in more than $25^{\circ}C$. 2. Amounts of propionic acid generated were 238.56mg/kg, 162.14mg/kg and 155.49mg/kg for swine, poultry, and cattle manure, respectively, during the period of incubation. In the case of swine manure, 78.52%(187.32mg/kg) of propionate emitted from all the temperature treatments was produced in the $25^{\circ}C$ and 79.1% of them was intensively emerged from 3day, 4day and 5day of the $25^{\circ}C$ treatment. In the case of poultry manure, 35.12%(56.95mg/kg) and 45.89%(74.40mg/kg) of the propionate amounts were produced in the $25^{\circ}C$ and in the $37^{\circ}C$, respectively. In the case of cattle manure, 28.21% (43.86mg/kg) and 49.30% (76.66mg/kg) of the propionate amounts were produced in the $10^{\circ}C$ and in the $25^{\circ}C$, respectively. Accordingly, propionate evolved from poultry manure was characteristic of being mainly produced in more than $25^{\circ}C$ and from cattle manure, in less than $25^{\circ}C$, respectively. 3. Amount of butyric acid generated were 1,463.87mg/kg, 96.72mg/kg and 129.18mg/kg for swine, poultry, and cattle manure, respectively, during the period of incubation. The time intensively emerged from the period of incubation was differently generated from the incubation temperature and animal feces. 4. Amounts of iso-valeric acid generated were 6,885.99mg/kg, 399.28mg/kg and 307.47mg/kg for swine, cattle and poultry manure, respectively, during the period of incubation. In the case of swine and cattle manure, 28.22%(1,943.52mg/kg) and 48.56%(193.90mg/kg) in the $25^{\circ}C$, 68.76%(4,734.90mg/kg) and 46.93%(187.40mg/kg) in the $37^{\circ}C$, respectively, were occupied. Accordingly, iso-valeric acid evolved from swine and cattle manure was characteristic of being mainly produced in more than $25^{\circ}C$. In the case of poultry manure, 59.89%(184.13mg/kg) of iso-valeric acid generated from all the temperature treatments was produced in the $37^{\circ}C$ and 100% of them was intensively emerged from 2 day and 3 day of the $37^{\circ}C$ treatment.

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Effects of Boliing, Steaming, and Chemical Treatment on Solid Wood Bending of Quercus acutissima Carr. and Pinus densiflora S. et. Z. (자비(煮沸), 증자(蒸煮) 및 약제처리(藥劑處理)가 상수리나무와 소나무의 휨가공성(加工性)에 미치는 영향(影響))

  • So, Won-Tek
    • Journal of the Korean Wood Science and Technology
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    • v.13 no.1
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    • pp.19-62
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    • 1985
  • This study was performed to investigate: (i) the bending processing properties of silk worm oak (Quercus acutissima Carr.) and Korean red pine (Pinus densiflora S. et Z.) by boiling and steaming treatments; (ii) the effects of interrelated factors - sapwood and heartwood, annual ring placement, softening temperature and time, moisture content. and wood defects on bending processing properties; (iii) the changing rates of bending radii after release from a tension strap, and (iv) the improving methods of bending process by treatment with chemicals. The size of specimens tested was $15{\times}15{\times}350mm$ for boiling and steaming treatments and $5{\times}10{\times}200mm$ for treatments with chemicals. The specimens were green for boiling treatments and dried to 15 percent for steaming treatments. The specimens for treatments with chemicals were soaked in saturated urea solution, 35 percent formaldehyde solution, 25 percent polyethylene glycol -400 solution, and 25 percent ammonium hydroxide solution for 5 days and immediately followed the bending process, respectively. The results obtained were as follows: 1. The internal temperature of silk worm oak and Korean red pine by boiling and steaming time was raised slowly to $30^{\circ}C$ but rapidly from $30^{\circ}C$ to $80-90^{\circ}C$ and then slowly from $80-90^{\circ}C$ to $100^{\circ}C$. 2. The softening time required to the final temperature was directly proportional to the thickness of specimen. The time required from $25^{\circ}C$ to $100^{\circ}C$ for 15mm-squared specimen was 9.6-11.2 minutes in silk worm oak and 7.6-8.1 minutes in Korean red pine. 3. The moisture content (M.C.) of specimen by steaming time was increased rapidly first 4 minutes in the both species, and moderately from 4 to 20 minutes and then slowly and constantly in silk worm oak, and moderately from 4 to 15 minutes and then slowly and constantly in Korean red pine. The M.C. of 15mm-squared specimen in 50 minutes of steaming was increased to 18.0 percent in the oak and 22.4 percent in the pine from the initial conditioned M.C. of 15 percent The rate of moisture adsorption measured was therefore faster in the pine than in the oak. 4. The mechanical properties of the both species were decreased significantly with the increase of boiling rime. The decrement by the boiling treatment for 60 minutes was measured to 36.6-45.0 percent in compressive strength, 12.5-17.5 percent in tensile strength, 31.6-40.9 percent in modulus of rupture, and 23.3-34.6 percent in modulus of elasticity. 5. The minimum bending radius (M.B.R.) of sapwood and heartwood was 60-80 mm and 90 mm in silk worm oak, and 260 - 300 mm and 280 - 300 mm in Korean red pine, respectively. Therefore, the both species showed better bending processing properties in sapwood than in heartwood. 6. The M.B.R. of edge-grained and flat-grained specimen in suk worm oak was 60-80 mm, but the M.B.R. in Korean red pine was 240-280 mm and 260-360 mm, respectively. Comparing the M.B.R. of edge-grained with flat-grained specimen, in the pine the edge-grained showed better bending processing property than the flat-grained. 7. The bending processing properties of the both species were improved by the rising of softening temperature from $40^{\circ}C$ to $100^{\circ}C$. The minimum softening temperature for bending was $90^{\circ}C$ in silk worm oak and $80^{\circ}C$ in Korean red pine, and the dependency of softening temperature for bending was therefore higher in the oak than in the pine. 8. The bending processing properties of the both species were improved by the increase of softening time as well as temperature, but even after the internal temperature of specimen reaching to the final temperature, somewhat prolonged softening was required to obtain the best plastic conditions. The minimum softening time for bending of 15 mm-squared silk worm oak and Korean red pine specimen was 15 and 10 minutes in the boiling treatment, and 30 and 20 minutes in the steaming treatment, respectively. 9. The optimum M.C. for bending of silk worm oak was 20 percent, and the M.C. above fiber saturation point rather degraded the bending processing property, whereas the optimum M.C. of Korean red pine needed to be above 30 percent. 10. The bending works in the optimum conditions obtained as seen in Table 24 showed that the M.B.R. of silk worm oak and Korean red pine was 80 mm and 240 mm in the boiling treatment, and 50 mm and 280 mm in the steaming treatment, respectively. Therefore, the bending processing property of the oak was better in the steaming than in the boiling treatment, but that of the pine better in the boiling than in the steaming treatment. 11. In the bending without a tension strap, the radio r/t of the minimum bending radius t to the thickness t of silk worm oak and Korean red pine specimen amounted to 16.0 and 21.3 in the boiling treatment, and 17.3 and 24.0 in the steaming treatment, respectively. But in the bending with a tension strap, the r/t of the oak and the pine specimen decreased to 5.3 and 16.0 in t he boiling treatment, and 3.3 and 18.7 in the steaming treatment, respectively. Therefore, the bending processing properties of the both species were significantly improved by the strap. 12. The effect of pin knot on the degradation of bending processing property was very severe in silk worm oak by side, e.g. 90 percent of the oak specimens with pin knot on the concave side were ruptured when bent to a 100 mm radius but only 10 percent of the other specimens with pin knot on the convex side were ruptured. 13. The changing rate in the bending radius of specimen bent to a 300 mm radius after 30 days of exposure to room temperature conditions was measured to 4.0-10.3 percent in the boiling treatment and 13,0-15.0 percent in the steaming treatment. Therefore, the degree of spring back after release was higher in the steaming than in the boiling treatment. And the changing rate of moisture-proofing treated specimen by expoxy resin coating was only -1.0.0 percent. 14. Formaldehyde, 35 percent solution, and 25 percent polyethylene glycol-400 solution found no effect on the plasticization of the both species, but saturated urea solution and 25 percent ammonium hydroxide solution found significant effect in comparison to non-treated specimen. But the effect of the treatment with chemicals alone was inferior to that of the steaming treatment, and the steaming treatment after the treatment with chemicals improved 10-24 percent over the bending processing property of steam-bent specimen. 15. Three plasticity coefficients - load-strain coefficient, strain coefficient, and energy coefficient - were evaluated to be appropriate for the index of bending processing property because the coefficients had highly significant correlation with the bending radius. The fitness of the coefficients as the index was good at load-strain coefficient, energy coefficient, and strain coefficient, in order.

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A Study of Altered IL-6 and TNF-α Expression in Peritoneal Fluid of Patients with Endometriosis (자궁내막증 환자의 복강 액내 IL-6와 TNF-α의 변화 양상에 관한 연구)

  • Kang, Jeong-Bae;Lee, Young-Kyeong
    • Clinical and Experimental Reproductive Medicine
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    • v.33 no.1
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    • pp.45-52
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    • 2006
  • Objective: Our purpose was to investigate the relationship between the levels of IL-6 and tumor necrosis factor-${\alpha}$ in the peritoneal fluid of women with and without endometriosis and infertile women. Methods: This study is prospective and case-control study in University hospital, enrolled thirty-four women with laparoscopic findings of minimal to severe endometriosis, and thirty-seven women with no visual evidence of pelvic endometriosis and with benign gynecologic disease. IL-6 and tumor necrosis factor-${\alpha}$ levels in peritoneal fluid were determined using commercial ELISA. IL-6 and tumor necrosis factor-${\alpha}$ concentrations were compared among women with and without endometriosis, and with infertile and fertile women, and then also compared according the revised American Fertility Society classification. Results: IL-6 and tumor necrosis factor-${\alpha}$ concentrations were higher than in the peritoneal fluid of women with endometriosis than in matched normal controls. Cyclic variations in IL-6 concentrations were seen in peritoneal fluid from patients with endometriosis: the concentrations in the secretory phase were significantly higher than those in the proliferative phase. The concentrations were higher than among of infertile women than in fertile women. A significant correlation between IL-6 and tumor necrosis factor-${\alpha}$ concentrations and endometriosis stage III and IV was noted. Conclusion: Increased levels of IL-6 and tumor necrosis factor-${\alpha}$ in patients with endometriosis in the peritoneal fluid may be relate to the pathogenesis of endometriosis suggesting that partially contribute to the disturbed immune regulation observed in patients with endometriosis.

Multi-level Analysis of the Antecedents of Knowledge Transfer: Integration of Social Capital Theory and Social Network Theory (지식이전 선행요인에 관한 다차원 분석: 사회적 자본 이론과 사회연결망 이론의 결합)

  • Kang, Minhyung;Hau, Yong Sauk
    • Asia pacific journal of information systems
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    • v.22 no.3
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    • pp.75-97
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    • 2012
  • Knowledge residing in the heads of employees has always been regarded as one of the most critical resources within a firm. However, many tries to facilitate knowledge transfer among employees has been unsuccessful because of the motivational and cognitive problems between the knowledge source and the recipient. Social capital, which is defined as "the sum of the actual and potential resources embedded within, available through, derived from the network of relationships possessed by an individual or social unit [Nahapiet and Ghoshal, 1998]," is suggested to resolve these motivational and cognitive problems of knowledge transfer. In Social capital theory, there are two research streams. One insists that social capital strengthens group solidarity and brings up cooperative behaviors among group members, such as voluntary help to colleagues. Therefore, social capital can motivate an expert to transfer his/her knowledge to a colleague in need without any direct reward. The other stream insists that social capital provides an access to various resources that the owner of social capital doesn't possess directly. In knowledge transfer context, an employee with social capital can access and learn much knowledge from his/her colleagues. Therefore, social capital provides benefits to both the knowledge source and the recipient in different ways. However, prior research on knowledge transfer and social capital is mostly limited to either of the research stream of social capital and covered only the knowledge source's or the knowledge recipient's perspective. Social network theory which focuses on the structural dimension of social capital provides clear explanation about the in-depth mechanisms of social capital's two different benefits. 'Strong tie' builds up identification, trust, and emotional attachment between the knowledge source and the recipient; therefore, it motivates the knowledge source to transfer his/her knowledge to the recipient. On the other hand, 'weak tie' easily expands to 'diverse' knowledge sources because it does not take much effort to manage. Therefore, the real value of 'weak tie' comes from the 'diverse network structure,' not the 'weak tie' itself. It implies that the two different perspectives on strength of ties can co-exist. For example, an extroverted employee can manage many 'strong' ties with 'various' colleagues. In this regards, the individual-level structure of one's relationships as well as the dyadic-level relationship should be considered together to provide a holistic view of social capital. In addition, interaction effect between individual-level characteristics and dyadic-level characteristics can be examined, too. Based on these arguments, this study has following research questions. (1) How does the social capital of the knowledge source and the recipient influence knowledge transfer respectively? (2) How does the strength of ties between the knowledge source and the recipient influence knowledge transfer? (3) How does the social capital of the knowledge source and the recipient influence the effect of the strength of ties between the knowledge source and the recipient on knowledge transfer? Based on Social capital theory and Social network theory, a multi-level research model is developed to consider both the individual-level social capital of the knowledge source and the recipient and the dyadic-level strength of relationship between the knowledge source and the recipient. 'Cross-classified random effect model,' one of the multi-level analysis methods, is adopted to analyze the survey responses from 337 R&D employees. The results of analysis provide several findings. First, among three dimensions of the knowledge source's social capital, network centrality (i.e., structural dimension) shows the significant direct effect on knowledge transfer. On the other hand, the knowledge recipient's network centrality is not influential. Instead, it strengthens the influence of the strength of ties between the knowledge source and the recipient on knowledge transfer. It means that the knowledge source's network centrality does not directly increase knowledge transfer. Instead, by providing access to various knowledge sources, the network centrality provides only the context where the strong tie between the knowledge source and the recipient leads to effective knowledge transfer. In short, network centrality has indirect effect on knowledge transfer from the knowledge recipient's perspective, while it has direct effect from the knowledge source's perspective. This is the most important contribution of this research. In addition, contrary to the research hypothesis, company tenure of the knowledge recipient negatively influences knowledge transfer. It means that experienced employees do not look for new knowledge and stick to their own knowledge. This is also an interesting result. One of the possible reasons is the hierarchical culture of Korea, such as a fear of losing face in front of subordinates. In a research methodology perspective, multi-level analysis adopted in this study seems to be very promising in management research area which has a multi-level data structure, such as employee-team-department-company. In addition, social network analysis is also a promising research approach with an exploding availability of online social network data.

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Optimum Size Selection and Machinery Costs Analysis for Farm Machinery Systems - Programming for Personal Computer - (농기계(農機械) 투입모형(投入模型) 설정(設定) 및 기계이용(機械利用) 비용(費用) 분석연구(分析硏究) - PC용(用) 프로그램 개발(開發) -)

  • Lee, W.Y.;Kim, S.R.;Jung, D.H.;Chang, D.I.;Lee, D.H.;Kim, Y.H.
    • Journal of Biosystems Engineering
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    • v.16 no.4
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    • pp.384-398
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    • 1991
  • A computer program was developed to select the optimum size of farm machine and analyze its operation costs according to various farming conditions. It was written in FORTRAN 77 and BASIC languages and can be run on any personal computer having Korean Standard Complete Type and Korean Language Code. The program was developed as a user-friendly type so that users can carry out easily the costs analysis for the whole farm work or respective operation in rice production, and for plowing, rotarying and pest controlling in upland. The program can analyze simultaneously three different machines in plowing & rotarying and two machines in transplanting, pest controlling and harvesting operations. The input data are the sizes of arable lands, possible working days and number of laborers during the opimum working period, and custom rates varying depending on regions and individual farming conditions. We can find out the results such as the selected optimum combination farm machines, the overs and shorts of working days relative to the planned working period, capacities of the machines, break-even points by custom rate, fixed costs for a month, and utilization costs in a hectare.

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Effects of Addition Level and Chemical Type of Propionate Precursors in Dicarboxylic Acid Pathway on Fermentation Characteristics and Methane Production by Rumen Microbes In vitro

  • Li, X.Z.;Yan, C.G.;Choi, S.H.;Long, R.J.;Jin, G.L.;Song, Man K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.22 no.1
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    • pp.82-89
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    • 2009
  • Two in vitro experiments were conducted to examine the effects of propionate precursors in the dicarboxylic acid pathway on ruminal fermentatation characteristics, $CH_4$ production and degradation of feed by rumen microbes. Fumarate or malate as sodium salts (Exp. 1) or acid type (Exp. 2) were added to the culture solution (150 ml, 50% strained rumen fluid and 50% artificial saliva) to achieve final concentrations of 0, 8, 16 and 24 mM, and incubated anaerobically for 0, 1, 3, 6, 9 and 12 h at $39^{\circ}C$. For both experiments, two grams of feed consisting of 70% concentrate and 30% ground alfalfa (DM basis) were prepared in a nylon bag, and were placed in a bottle containing the culture solution. Addition of fumarate or malate in both sodium salt and acid form increased (p<0.0001) pH of culture solution at 3, 6, 9 and 12 h incubations. The pH (p<0.0001) and total volatile fatty acids (VFA, p<0.05) were enhanced by these precursors as sodium salt at 3, 6 and 9 h incubations, and pH (p<0.001) and total VFA (p<0.01) from fumarate or malate in acid form were enhanced at a late stage of fermentation (9 h and 12 h) as the addition level increased. pH was higher (p<0.001) for fumarate than for malate as sodium salt at 3 h and 6 h incubations. Propionate ($C_3$) proportion was increased (p<0.0001) but those of $C_2$ (p<0.05) and $C_4$ (p<0.01 - p<0.001) were reduced by the addition of sodium salt precursors from 3 h to 12 incubation times while both precursors in acid form enhanced (p<0.011 - p<0.0001) proportion of $C_3$ from 6h but reduced (p<0.018 - p<0.0005) $C_4$ proportion at incubation times of 1, 3, 9 and 12 h. Proportion of $C_3$ was increased (p<0.05 - p<0.0001) at all incubation times by both precursors as sodium salt while that of $C_3$ was increased (p<0.001) from 6h but $C_4$ proportion was decreased by both precursors in acid form as the addition level increased. Proportion of $C_3$ was higher (p<0.01 - p<0.001) for fumarate than malate as sodium salt from 6 h incubation but was higher for malate than fumarate in acid form at 9 h (p<0.05) and 12 h (p<0.01) incubation times. Increased levels (16 and 24 mM) of fumarate or malate as sodium salt (p<0.017) and both precursors in acid form (p<0.028) increased the total gas production, but no differences were found between precursors in both chemical types. Propionate precursors in both chemical types clearly reduced (p<0.0001 - p<0.0002) $CH_4$ production, and the reduction (p<0.001 - p<0.0001) was dose dependent as the addition level of precursors increased. The $CH_4$ generated was smaller (p<0.01 - p<0.0001) for fumarate than for malate in both chemical types. Addition of fumarate or malate as sodium type reduced (p<0.004) dry matter degradation while both precursors in both chemical types slightly increased neutral detergent fiber degradability of feed in the nylon bag.