• 설비공학논문집
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• 제4권1호
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• pp.33-47
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• 1992

Experimental investigation on the performance of a heat pump system using refrigerant mixtures is done. The condenser and the evaporator are double pipe heat exchangers of counter flow type and the compressor is driven by a variable speed motor. The refrigerant mixture used in the experiment is R22/R142b. Experiments are performed by changing the compressor speed, composition on ratio of mixture, and the average temperatures of condenser and evaporator. The compressor work, heating capacity and the coefficient of performance are calculated. Results show that the heating capacity can be changed by varying the mass flow rate of refrigerant mixtures to meet the heating load. It is shown that the capacity control by changing the composition ratio is more effective than by changing the compressor speed. Under the condition where the external conditions are fixed and the heating loads are equal, the coefficient of performance has its maximum value near 50 : 50 mass fraction of the refrigerant mixture in this study.

• 동의생리병리학회지
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• 제36권2호
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• pp.79-87
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• 2022

In this study, extracts of Boswellia serrata gum resin, Curcuma longa rhizome, and Terminalia chebula fruit were combined in different ratios, and their anti-osteoarthritis effects were compared to determine which combination had the best synergistic effect. B. serrata, C. longa, and T. chebula extracts in a 2:1:2 ratio exhibited higher antioxidative activity in scavenging DPPH radicals than did the individual extracts alone or the other extract combinations. Additionally, the 2:1:2 combination significantly improved the levels of enzymatic antioxidants and antioxidant-related proteins. Moreover, this same combination ratio decreased the protein levels of matrix metalloproteinase (MMP) 3 and MMP13 in interleukin-1β-stimulated human articular chondrocytes (HCHs) and increased those of aggrecan and collagen type II alpha 1 chain (COL2A1). Analysis of the underlying mechanisms revealed that the 2:1:2 combination significantly inhibited the phosphorylation of nuclear factor kappa B (NF-κB) p65, extracellular regulated protein kinase (ERK), and p38 mitogen-activated protein kinase (MAPK). Therefore, the 2:1:2 combination of these three plant extracts has the best potential for use as an effective dietary supplement for improving joint health compared with the individual extracts and their other combination ratios.

• 한국가금학회지
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• 제29권1호
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• pp.25-35
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• 2002

조기제한사양의 강도(정도)와 시기 및 기간이 육계의 보상성장과 사료효율 및 복강지방 축적에 미치는 영향을 구명하기 위해 2개의 실험을 실시하였는데, 실험 1에서는 7일령된 무감별 육계 240수를 4처리 3반복에 반복당 20수씩 공시하여 7일령에서부터 49일령까지 실시하였다. 대조구(C)는 7일령부터 49일령까지 전기간 육계 전기사료와 후기사료를 자유채식을 시켰으며, 시험구(T1,T2 및 T3)들은 각각 1일 0.75 kcal ME/9B $W^{0.67}$로 7일령부터 9일령까지 3일간, 1.50 kcal ME/gB $W^{0.67}$로 7일령부터 11일령까지 5일간 및 2.25 kcal ME/gB\$^{0.67}$로 7일령부터 13일령까지 7일간 육계전기사료를 제한급여하였다. 실험 2는 4일령된 무감별 육계 420수를 7처리 3반복, 반복당 20수씩 공시하여 4일령에서부터 49일령까지 실시하였는데 대조구(C)는 4일령부터 49일령까지 전기간 육계 전기사료와 후기사료를 자유채식을 시켰으며, 시험구(T1~T6)들은 모두 1일 0.75kcal ME/gB $W^{0.67}$로 4,7일 및 10일령에 3일간 또는 5일간육계전기사료를 제한급여하였으며, 제한사양이 끝난 시험구들은 전기사료 및 후기사료를 자유채식시켰다. 실험 1에서 제한사양기간을 포함한 21일령가지의 증체량은 대조구에 비해 시험구들이 유의적으로 적었으나(P<0.05), 22일령부터 49일령까지의 증체량은 대조구에 비해 시험구들이 유의적으로 높았으며(P<0.05), 전기간인 7일령부터 49일령까지의 증체량과 49일령 체중은 처리간에 유의적 차이가 없었다. 제한사양후부터 21일령까지의 사료섭취량은 T1구를 제외한 나머지 시험구에서는 대조구와 유의적인 차이를 보이지 않았으며, 22~47일령의 사료섭취량은 처리간에 유의적인 차이가 없었으나, 전기간 섭취량은 대조구에 비해 시험구들이 유의적으로 적게 섭취하였다 (P<0.05). 제한사양기간을 포함한 7일령부터 21일령까지의 사료요구율은 T1구만 유의적으로 낮았으며(P<0.05), 22일령부터 49일령가지의 사료요구율과 전기간동안의 사료요구율은 대조구에 비해서 시험구들이 유의적으로 낮았다(P<0.05) , 복강내지방함량 및 전기간 폐사율은 처리간에 유의적 차이가 없었다.

• 농업생명과학연구
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• 제46권5호
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• pp.83-90
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• 2012

A study was investigated the effects of the probiotic mixture (PM) contained Lactobacillus plantarum (L. plantarum) SY-99 $2.4{\times}10^9CFU/kg$ and Bacillus subtilis (B. subtilis) SJ-61 $2.2{\times}10^9CFU/kg$ on growth performance and fecal microflora counts of broiler chickens. Referred to the previous studies, a total of 160 one-day-old male broiler chicken (Ross 308) were randomly assigned to four experimental groups, which were a basal diet alone (control) and supplemented with PM 0.1 g/kg feed (T1), PM 0.2 g/kg feed (T2), and PM 0.4 g/kg feed (T3). After 28 days of administration, the average daily feed intake of T1 and T3 was significantly different compared to that of control (p<0.05). In addition, the feed conversion ratio of T2 and T3 was significantly improved compared to that of control (p<0.05). On the 28th day after administration, all treatment groups were significantly increased fecal lactic acid bacteria (LAB) counts and decreased fecal Enterobacteriaceae (ENT) counts compared to T1 (p<0.05). The results of this study indicated that the combination of L. plantarum and B. subtilis strains in the range of 0.2-0.4 g/kg feed could be used for the improvement of growth performance and fecal microflora in broiler chickens.

• The Korean journal of internal medicine
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• 제33권6호
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• pp.1103-1110
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• 2018

Background/Aims: Several epidemiological studies have validated the association of interleukin gene polymorphisms with acute pancreatitis (AP) in different populations. However, there have been few studies in Asian ethnic groups. We aimed to investigate the relationships between inflammatory cytokine polymorphisms and AP as pilot research in a Korean ethnic group. Methods: Patients who had been diagnosed with AP were prospectively enrolled. DNA was extracted from whole blood, and DNA sequencing was subsequently performed. Single-nucleotide polymorphisms (SNPs) of the interleukin $1{\beta}$ (IL1B), interleukin 1 receptor antagonist (IL1RN), and tumor necrosis factor ${\alpha}$ (TNFA) genes of patients with AP were compared to those of normal controls. Results: Between January 2011 and January 2013, a total of 65 subjects were enrolled (40 patients with AP vs. 25 healthy controls). One intronic SNP (IL1RN -1129T>C, rs4251961) was significantly associated with the risk of AP (odds ratio, 0.304; 95% confidence interval, 0.095 to 0.967; p = 0.043). However, in our study, AP was not found to be associated with polymorphisms in the promoter regions of inflammatory cytokine genes, including IL1B (-118C>T, c47+242C>T, +3954C/T, and -598T>C) and TNFA (-1211T>C, -1043C>A, -1037C>T, -488G>A, and -418G>A). Conclusions: IL1RN -1129T>C (rs4251961) genotypes might be associated with a significant increase of AP risk in a Korean ethnic group.

• 한국임상수의학회지
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• 제16권2호
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• pp.454-462
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• 1999

Corticosteroids have long been used for anti-inflammatory, anti-rheumatoid and other purposes in hospital. These effects may be due to inhibit immune reaction. So the animal given corticosteroids was more susceptible to infection because of immunosuppressive effect of corticosteroids. The purpose of this study was to investigate the effects of prednisolone on the lymphocyte subset in the spleen, immunoglobulin in serum, spleen weight, thymus weight and total WBC in peripheral blood. Mice were randomized into 3 groups. Each group has 24 mice. The small dosage group were given by 4 mg/kg/day of prednisolone for 4 days and the large dosage group were given by 8 mg/kg/day respectively. Prednisolone was suspended in saline and orally administered. Mice in control group were given saline alone. Eight mice in each group were sacrificed every week after administration of predisolone. The weight of thymus and spleen were mesured immediately. Lymphocytes were taken from spleen and these cells were analysed by flow cytometry. Also the concentration of total immunoglobulins in serum were assayed by enzyme-linked immunosorbant assay (ELISA). T cell, T-helper cell and T-cytotoxic cell were all significantly (P<0.05) decreased at 1 week after administration of predisolone and at 2 weeks they recovered similarly to that of control. Population of B cell showed various distribution. The concentration of total immunoglobulins in serum was not changed significantly. The weight ratio of spleen to body decreased significantly (P＜0.05) during predisolone administration but increased at 1 week later, Eventually the weight ratio was recovered to that of control at 2 weeks. The weight ratio of thymus to body decreased significantly (P<0.05) by prednisolone and recovered gradually up to normal ratio 2 weeks later.

• Journal of Korean Neurosurgical Society
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• 제41권5호
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• pp.301-305
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• 2007

Objective : The postoperative subsidence of anterior cervical interbody fusion for cervical degenerative diseases gives rise to segmental kyphotic collapse, screw loosening, and chronic neck pain. So, intraoperative custom-made polymethylmethacrylate [PMMA] C-cage has been developed to prevent subsidence following anterior cervical fusion. Methods : A total of patients who underwent anterior cervical interbody fusion with a intraoperative custom - made cervical cage filled with local bone and demineralized bone matrix [group A] were analyzed prospectively from June 2004 to June 2005. These were compared with 40 patients who were treated with iliac bone graft [group B]. We evaluated subsidence ratio, change of segmental angle, distraction length and segmental angle. Statistical analysis was performed using independent sample t-test and Pearson correlation coefficient. Results : Group A had a statistically significant decrease in subsidence ratio [$0.64{\pm}0.43%$, p=0.00]. distraction length [$2.42{\pm}1.25\;mm$, p=0.02], and follow angle change [$1.78{\pm}1.69^{\circ}$, p=0.01] as compared with Group B. However, there was no statistically significant difference in postoperative segmental angle change [p=0.66]. On the analysis of the correlation coefficient, the parameters showed no interrelationships in the group A. On the other hand, subsidence ratio was affected by distraction length in the group B [Pearson correlation=0.448]. Conclusion : This operative technique would be contributed for the reduction of a postoperative subsidence after the anterior cervical interbody fusion procedure for cervical disc disease with moderate to severe osteoporotic condition and segmental loss of lordosis.

• Geomechanics and Engineering
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• 제1권3호
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• pp.219-239
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• 2009

Vertical vibration tests were conducted using model footings of different size and mass resting on the surface of finite sand layer with different height to width ratios and underlain by either rigid concrete base or natural red-earth base. A comparative study of the ratio of predicted and observed natural frequency ratio of the finite sand stratum was made using the calculated values of equivalent stiffness suggested by Gazetas (1983) and Baidya and Muralikrishna (2001). Comparison of results between model footings resting on finite sand stratum underlain by the rigid concrete base and the natural red-earth base showed that, the presence of a finite base of higher rigidity increases the resonant frequency significantly. With increase in H/B ratio beyond 2.0, the influence of both the rigid concrete and natural red-earth base decreases. Increase in the contact area of the footing increases the resonant frequency of the model footings resting on finite sand stratum underlain by both the types of finite bases. Both the predicted and the observed resonant frequency ratio decreases with increase in force rating and height to width ratio for a given series of model footing.

• Steel and Composite Structures
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• 제19권5호
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• pp.1299-1319
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• 2015

This paper presents a detailed parametric study, conducted using finite element tools to cover a range of several geometric and material parameters, on the behaviour of thin-walled partially encased composite (PEC) columns. The PEC columns studied herein are composed of thin-walled built-up H-shaped steel sections with concrete infill cast between the flanges. Transverse links are provided between the opposing flanges to improve resistance to local buckling. The parametric study is confined to eccentrically-loaded columns subjected to major axis bending only. The parameters that were varied include the overall column slenderness ratio (L/d), load eccentricity ratio (e/d), link spacing-to-depth ratio (s/d), flange plate slenderness ratio (b/t) and concrete compressive strength ($f_{cu}$). The overall column slenderness ratio was chosen to be the primary variable with values of 5, 10 and 15. Other parameters were varied within each case of L/d ratio. The effects of the selected parameters on the behaviour of PEC columns were studied with respect to the failure mode, peak axial load, axial load versus average axial strain response, axial load versus lateral displacement response, moment versus lateral displacement behaviour and the axial load-moment interaction diagram. The results of the parametric study are presented in the paper and the influences of each of the parameters investigated are discussed.

• 한국토양비료학회지
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• 제21권3호
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• pp.254-263
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• 1988

토양부식산(土壤腐植酸) 형태(形態)(Rp, B, A, P)별(別) 부식산(腐植酸)과 fulv 산중(酸中) amino 산(酸)의 함량(含量)과 조성(組成)을 규명코자 부식산(腐植酸)과 fluv산(酸)을 각각(各各) 분수(分雖) 정렬(精裂)하여 분석(分析)해 얻은 결과(結果)를 요약(要約)하면 다음과 같다. 1. 부식(腐植)의 조방(粗放) 전부식량(全部植量)$(H_T)$, 부식산량(腐植酸量)(a), fulv 산량(酸量)(b), 색조계수(色調係數)$({\Delta}logK)$는 $Rp{\rightarrow}B{\rightarrow}A{\rightarrow}P$형(型)으로 갈수록 적어졌고 전질소(全窒素) 전탄소(全炭素)도 같은 경향이었다. 2. 부식산중(腐植酸中) amino 산(酸)의 함량(含量) 및 조성(組成) 가. 부식산(腐植酸)의 형태별(形態別) 전(全) amino 산(酸)의 함량(含量)은 침엽수(針葉樹) 임토양(林土壤)에서는 Rp>B>A>P형(型)의 순(順)이었으나 활엽수(闊葉樹) 임토양(林土壤)에서는 P>A>Rp>B형(型)의 순(順)이었다. 전(全) amino산(酸)과 부식조성(腐植組成)과의 관계(關係)에서 침엽수림토양(針葉樹林土壤)에서 전탄소(全炭素)${\Delta}logK$와는 정(正)의 상관(相關)이 있었고 C/N율(率)과는 부(負)의 상관(相關)이 있었다. 활엽수림토양(闊葉樹林土壤)에서는 유의상관(有意相關)이 없었다. 나. 형태문(形態問) 산성(酸性), 중성(中性), 염기성(鹽基性) amino 산(酸)의 함량비(含量比)는 침엽수림토양(針葉樹林土壤)에서 산성(酸性) amino 산(酸)은 P>Rp>B>A 형(型)의 순(順), 중성(中性) amino 산(酸)은 Rp>B>A>P형(型)의 순(順), 염기성(鹽基性) amino 산(酸)은 B>A>Rp>P형(型)의 순(順)이었다. 함량(含量)은 중성(中性)>산성(酸性)>염기성(鹽基性) anomi 산(酸)의 순(順)이었다. 활엽수림토양(闊葉樹林土壤)에서는 산성(酸性) amino 산(酸) A>P>B>Rp형(形)의 순(順), 중성(中性) amino 산(酸)은 P>Rp>A>B 형(形)의 순(順), 염기성(鹽基性) amino 산(酸)은 $$P{\geq_-}$$ A > $$B{\geq_-}Rp$$형(形)으로 근소한 차이였다. 다. 형태별(形態別) 각(各) amino 산(酸) 함량(含量)에서는 전체적으로 aspartic acid, glycine, glutamic acid 가 많았고 histidine, tyrosine, methionine이 적었다. 3. Fulv 산중(酸中) amino 산(酸)의 함량(含量) 및 조성(組成) 가. 형태별(形態別) 전(全) amino 산(酸)의 함량(含量)은 두 토양(土壤) 공(共)히 Rp>B>P>A 형(形)의 순(順)이었다. 침엽수림토양(針葉樹林土壤)에서 전(全) amno산(酸)과 전탄소(全炭素), ${\Delta}logK$와 정(正)의 상관(相關)이 있었고 활엽수림토양(闊葉樹林土壤)에서는 전질소(全窒素), 전부식량(全腐植量)$(H_T)$, 부식산량(腐植酸量)(a), 색조계수(色調係數)$({\Delta}logK)$와는 정(正)의 상관(相關)이 있었고 C/N율(率)과는 부(負)의 상관(相關)이 있었다. 나. 형태문(形態問) 산성(酸性), 중성(中性), 염기성(鹽基性) amino 산(酸)의 함량비(含量比)는 두 토양(土壤) 공(共)히 Rp>B>P>A형(形)의 순(順)이었다. 다. 형태문(形態問) 각(各) amino 산(酸)의 함량(含量)을 비교(比較)할 때 전체적(全體的)으로 glycine, aspartic acid, alanine 이 많았고 tyrosine, methionine은 적었고 arginine은 거의 측정되지 않았다.