• 천문학회보
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• 제44권2호
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• pp.64.1-64.1
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• 2019

The first high-resolution spectroscopic and new multiband photometric observations of the semi-detached Algol type binary XZ CMi were performed at the Bohyunsan Optical Astronomy Observatory (BOAO) and the Sobaeksan Optical Astronomy Observatory (SOAO), respectively. A total of 34 spectra were obtained using the 1.8 m reflector of the BOAO equipped with the Bohyunsan Optical Echelle Spectrograph to construct the radial velocity (RV) curves of the eclipsing pair. New BVRI photometric light curves were also covered by using the SOAO 61cm reflector and a CCD camera. A detailed analysis of all eclipse timings shows that the orbital period of XZ CMi has varied in an upward parabolic variation superposed on a sinusoidal oscillation with a period of 38.0 yr and a semi-amplitude of 0.0071 days. From the spectral analysis, the effective temperature and the projected rotational velocity of the primary component were determined to be T_eff,1 = 7387±161 K and v₁sini = 122±6 km s^-1, respectively. Our simultaneous synthesis of the double-lined RV and BVRI light curves gives the reliable system parameters of XZ CMi with a mass ratio (q) of 0.314, an orbital inclination (i) of 81.9 deg and a large temperature difference (∆T) of 2481 K. The individual masses and radii of both components are M₁ = 1.91±0.08M_⊙, M₂ = 0.60±0.02M_⊙, R₁ = 1.60±0.02R_⊙, R₂ = 1.13±0.02R_⊙, respectively. Although the primary component is located inside the δ Sct and γ Dor instability strips, no evidence of pulsation in the system was detected. The possible evolutionary status of XZ CMi is discussed.

• Plant Breeding and Biotechnology
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• 제7권3호
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• pp.186-199
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• 2019

We selected 68 Chinese maize inbred lines to understand the genetic diversity, population structure, and marker-trait associations for eight agronomic traits and 50 simple sequence repeats (SSRs) markers. In this study, effective traits, such as days of anthesis (DA), days of silking (DS), ear height (EH), plant to ear height ratio (ER), plant height (PH), and leaf width (LW) were divided into PC1 and PC2 by PCA analysis for maize inbred lines. Genetic diversity analysis revealed a total of 506 alleles at 50 SSR loci. The mean number of alleles per locus was 10.12. The averages of genetic diversity (GD) and polymorphic information content (PIC) values were 0.771 and 0.743, respectively. Based on a membership probability threshold of 0.80, the population structure revealed that the total inbred lines were divided into three major groups with one admixed group. A marker-trait association using Q + K MLM showed that nine SSR markers (bnlg1017, umc2041, umc2400, bnlg105, umc1229, umc1250, umc1066, umc2092, and umc1426) were related with seven agronomic traits. Among these SSR markers, eight SSR markers were associated with only one agronomic trait (DA, DS, ER, LL, LW, PH, and ST), whereas one SSR marker (umc1229) was associated with two agronomic traits (DA and ST). These results will help in optimizing the choice of inbred lines for cross combinations, as well as in selecting markers for further maize breeding programs.

• Geomechanics and Engineering
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• 제36권3호
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• pp.259-276
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• 2024

The undrained shear strength is widely acknowledged as a fundamental mechanical property of soil and is considered a critical engineering parameter. In recent years, researchers have employed various methodologies to evaluate the shear strength of soil under undrained conditions. These methods encompass both numerical analyses and empirical techniques, such as the cone penetration test (CPT), to gain insights into the properties and behavior of soil. However, several of these methods rely on correlation assumptions, which can lead to inconsistent accuracy and precision. The study involved the development of innovative methods using extreme gradient boosting (XGB) to predict the pile set-up component "A" based on two distinct data sets. The first data set includes average modified cone point bearing capacity (q_t), average wall friction (f_s), and effective vertical stress (σ_vo), while the second data set comprises plasticity index (PI), soil undrained shear cohesion (S_u), and the over consolidation ratio (OCR). These data sets were utilized to develop XGBoost-based methods for predicting the pile set-up component "A". To optimize the internal hyperparameters of the XGBoost model, four optimization algorithms were employed: Particle Swarm Optimization (PSO), Social Spider Optimization (SSO), Arithmetic Optimization Algorithm (AOA), and Sine Cosine Optimization Algorithm (SCOA). The results from the first data set indicate that the XGBoost model optimized using the Arithmetic Optimization Algorithm (XGB - AOA) achieved the highest accuracy, with R2 values of 0.9962 for the training part and 0.9807 for the testing part. The performance of the developed models was further evaluated using the RMSE, MAE, and VAF indices. The results revealed that the XGBoost model optimized using XGBoost - AOA outperformed other models in terms of accuracy, with RMSE, MAE, and VAF values of 0.0078, 0.0015, and 99.6189 for the training part and 0.0141, 0.0112, and 98.0394 for the testing part, respectively. These findings suggest that XGBoost - AOA is the most accurate model for predicting the pile set-up component.

• 아태비즈니스연구
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• 제14권4호
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• pp.233-254
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• 2023

Purpose - This study aims to verify whether the effect of tax avoidance on corporate value is non-linear in the Korean financial markets. Design/methodology/approach - This study believes that the cause of the inconsistent empirical analysis results of previous studies that verified the relationship between tax avoidance and firm value may be an error in assuming linearity, and verifies whether a nonlinear relationship exists. The sample company in this study is a December settlement corporation listed on the Korean stock market, and the analysis period is from 2000 to 2021. In the empirical analysis model, Tobin's Q is used as a proxy for corporate value, tax avoidance is used as the main independent variable, and a regression model is designed with corporate size, growth rate, and debt ratio set as control variables. Findings - As a result of the empirical analysis, it can be confirmed that there is an inverted U-shaped nonlinear relationship between tax avoidance and corporate value. In the additional analysis using Ohlson (1995) firm valuation model for the robustness of the results of the empirical analysis, the same nonlinear value relationship between tax avoidance can be confirmed. Research implications or Originality - This study is considered to be meaningful in that it verifies the non-linear relationship of tax avoidance, which has not been attempted in previous studies. The meaning of the inverted U-shaped nonlinear relationship presented in this study is that corporate tax avoidance acts as a factor that increases corporate value up to a certain level, but rather becomes a factor that decreases corporate value when it exceeds a critical point. These results are expected to provide new perspectives and perspectives on tax avoidance to companies belonging to the Korean capital market.

• Journal of Microbiology and Biotechnology
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• 제34권3호
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• pp.725-734
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• 2024

CYP102A1 from Bacillus megaterium is an important enzyme in biotechnology, because engineered CYP102A1 enzymes can react with diverse substrates and produce human cytochrome P450-like metabolites. Therefore, CYP102A1 can be applied to drug metabolite production. Terpinen-4-ol is a cyclic monoterpene and the primary component of essential tea tree oil. Terpinen-4-ol was known for therapeutic effects, including antibacterial, antifungal, antiviral, and anti-inflammatory. Because terpenes are natural compounds, examining novel terpenes and investigating the therapeutic effects of terpenes represent responses to social demands for eco-friendly compounds. In this study, we investigated the catalytic activity of engineered CYP102A1 on terpinen-4-ol. Among CYP102A1 mutants tested here, the R47L/F81I/F87V/E143G/L188Q/N213S/E267V mutant showed the highest activity to terpinen-4-ol. Two major metabolites of terpinen-4-ol were generated by engineered CYP102A1. Characterization of major metabolites was confirmed by liquid chromatography-mass spectrometry (LC-MS), gas chromatography-MS, and nuclear magnetic resonance spectroscopy (NMR). Based on the LC-MS results, the difference in mass-to-charge ratio of an ion (m/z) between terpinen-4-ol and its major metabolites was 16. One major metabolite was defined as 1,4-dihydroxyp-menth-2-ene by NMR. Given these results, we speculate that another major metabolite is also a mono-hydroxylated product. Taken together, we suggest that CYP102A1 can be applied to make novel terpene derivatives.

• 농업과학연구
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• 제50권3호
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• pp.437-448
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• 2023

The large amount of energy required for successful crop production is the main challenge in greenhouse cropping systems. As a response to this challenge a comprehensive evaluation of greenhouse energy consumption was carried out in two structurally similar single-span greenhouses with different thermal curtain positions, with particular attention to energy productivity, specific energy, net energy, and energy ratio. The greenhouses are used for strawberry production. In the R-greenhouse (RGH), the thermal curtain hanged directly at the roof ridge, whereas in the Q-greenhouse (QGH), the thermal curtain was placed 5° from an imaginary vertical axis, from the middle of the roof ridge downwards to the north side of the greenhouse roof. The relevant data were recorded using standard methods. The results indicated that the energy expended in the RGH and QGH systems was 2,186.48 and 2,189.26 MJ/m², respectively. Electricity and nitrogen fertilizer contributed the highest energy input in both greenhouses and in all seasons. The output energy was 3.12 and 3.82 MJ/m², respectively, in RGH and QGH in season I and 4.40 and 4.87 MJ/m² in season II. In terms of energy expended, there was no significant difference between the two greenhouses, nor between the two seasons. These results indicate that greenhouses of the size used in this investigation are not viable in terms of energy productivity, energy-use efficiency, and subsequent economic performance. However, further studies should be conducted to scale-up the information obtained from this investigation.

• 한국가금학회지
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• 제33권3호
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• pp.233-238
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• 2006

Lanthanum을 비롯한 17가지 특수 원소를 일컬어 희토(rare earth)라 한다. 본 연구에서는 육계사료에 희토의 첨가 효과를 알아보기 위하여 2회의 사양 시험을 실시하였다. 시험에 이용한 희토는 순도 99% 이상의 염화 희토 혼합물$(RECl_3)$로 $LaCl_3$ 36.52%, $LaCl_3$ 28.14%, $PrCl_3$ 11.24%, 그리고 기타 희토원소 24.11%로 구성된 흰색 분말 형태이었다. 희토 급여 사육기간은 5주간이었으며, 본 연구의 주요 목적은 희토 급여가 육계의 성장을 촉진할 수 있는지, 유해성은 없는지, 그리고 적정 사료 첨가 수준을 구명하였다. 육계의 복강 지방 축적에 대해서도 알아보았다. 첫 번째 사양 시험에서는 시판 배합 사료에 대한 희토 첨가 효과를 검토하였다. Cobb육계 1일령 병아리 360수를 사용하였으며, 사료에 희토를 0, 100, 200, 400, 800, 그리고 1,600 mg/kg 수준으로 첨가하였다. 육계의 성장은 희토 100 mg/kg 첨가 수준에서 가장 우수하였으며, 증체량은 대조구에 비해 8.9%가 증가하였고(1,669.9 vs. 1,533.8 g/chick), 사료 요구율도 낮았다(p<0.05). 희토는 1,600 mg/kg 수준으로 매우 높게 급여할지라도 성장이 저해되지 않았으며, 대조구와 같은 증체와 사료 요구율을 보였으므로, 과다 급여에 의한 중독증은 없을 것으로 사료되었다. 두 번째 사양 시험은 실험 1의 결과에서는 육계사료에서 성장능력의 극대화를 위한 희토의 적정 첨가 수준이 $100\sim200mg/kg$으로 예측되었으므로 좀더 근접한 적정 수준을 알아보고자 희토를 0, 50, 100, 150 mg/kg 수준으로 첨가하였다. 시험 사료는 시판 사료에 있을 수 있는 항생제나 기타 성장 촉진용 사료 첨가제를 첨가하기 위하여 자가 배합하였으며, Ross육계 1일령 병아리 360수를 이용하였다. 시험 결과 희토 50 mg/kg의 첨가가 증체량과 사료 요구율에서 대조구나 다른 처리구들에 비해 월등히 좋은 결과를 나타내었다(p<0.05). 이 시험에서는 첫 번째 시험에서 보이지 않았던, 생체중에 대한 복강 지방 비율이 현저하게 감소한 것으로 나타났다(p<0.05). 본 실험 결과 육계사료에 희토의 첨가는 육계의 성장을 촉진하였으며, 사료 요구율 개선하였다. 이외에도 복강지방이 낮아지는 경향을 보였지만 일관성이 없었으므로 추후의 연구가 필요하다.

• 대한방사선치료학회지
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• 제18권1호
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• pp.1-5
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• 2006

목 적: 세기조절 방사선치료의 환자별 정도관리는 이온전리함을 이용한 일정 지점에서의 절대 선량 측정과 필름을 이용한 상대 선량측정의 두 단계로 구성된다. 이온전리함을 이용한 절대 선량 측정은 동일한 지점에서 치료계획상의 점선량과 실제 측정 점선량 간의 일치도에 대한 정보를 제공한다. 일반적으로 정확한 점선량을 측정하기 위해 volume이 작은 0.015 cc 이온전리함(pin point chamber, PTW, Germany)을 사용하고 있다. 그러나 이 경우 이온전리함의 볼륨이 작아 선량의 오차가 크게 나타나는 경우도 있어, 적합한 볼륨의 이온전리함 사용이 권고되기도 한다. 따라서 볼륨이 다른 세 가지의 이온전리함을 이용하여 점선량을 측정하여 치료계획상의 점 선량과 비교해 보고, 0.015 cc 이온전리함을 이용한 세기조절 방사선치료에서의 절대 점선량 측정의 유효성을 평가해 보고자 한다. 대상 및 방법: 두경부(Head & Neck) 종양의 세기조절 방사선치료가 요구되는 환자 6명을 대상으로 Sliding-window 방법의 IMRT 치료계획을 수립하였으며 치료기는 21EX(Varian, USA) 선형가속기의 6 MV 광자선을 사용하였다. 측정 조건은 120 millenium MLC를 이용하여 Gantry 0도에서 300 MU/min의 선량률로 선원-이온전리함(source-axis-distance)거리를 100 cm, 고체팬텀의 표면으로부터 5 cm 깊이에 이온전리함을 위치시켰다. 치료계획용 컴퓨터(CAD-Plan, USA)에서 결정된 결과를 0.015 cc(pin point, type 31014, PTW, Germany), 0.125 cc(micro type 31002, PTW, Germany ), 0.6 cc(famer type 30002, PTW, Germany) 전리함에 각각 조사하여 측정치를 비교 분석하였다. 측정점은 선량값의 변화가 상대적으로 적은 선량 저변동 영역(Low-gradient area)에 위치시켰다. 결 과: 각각의 이온전리함을 이용하여 측정한 결과 0.015 cc의 경우 평균 ${\pm}0.91%$, 0.125 cc의 경우 ${\pm}0.52%$, 0.6 cc의 경우 ${\pm}0.76%$로 0.125 cc 이온전리함의 경우가 모든 측정조건에서 가장 적은 오차를 보였다. 결 론: 세기조절 방사선치료에 있어서 선량의 평가는 매우 중요하다. 방사선치료가 정밀해지는 만큼 정확한 선량평가가 이루어져야 한다. 점선량을 평가하기 위해 제작된 0.015 cc 이온전리함은 작은 출력신호와 큰 신호 대 잡음비가 절대 선량 측정 시 선량오차를 발생시키는 큰 요인으로 작용할 수 있다. 반면에 이온전리함의 볼륨이 큰 경우 출력신호가 크므로 정확한 선량을 반영할 수 있으나, 작은 측정점에 이온전리함을 정확히 위치시키기 어려워 절대 점선량을 측정하기 어려운 단점이 있다. 따라서 본 연구의 결과에서 본 바와 같이 세기조절 방사선치료의 절대 점선량 측정에는 오차가 상대적으로 적은 0.125 cc 이온전리함의 사용이 고려되어야 한다.

• 한국가축번식학회지
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• 제25권2호
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• pp.163-169
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• 2001

본 연구는 마우스 정자-난자 결합분석 법(oocytes-sperm binding assay; OSBA)을 이용하여 단백질원, 배양액의 질, 난자의 성숙도에 따라서 정자와 난자의 결합능력을 알아보고 그 유용성을 알아보기 위하여 실시하였다. 4~5주령의 hybrid(C57BL/6 $\times$ CBA/N) F$_1$ 암컷에서 회수된 미수정란에 0.1% hyaluronidase를 이용하여 난구세포를 제거하였으며, 제1극체의 존재유무에 따라 Met. II(mature)와 Met. I(intermediate mature)로 구분하였다. 암컷과 동일 계통의 8주령 이상 된 수컷에서 회수된 정소상체 미부정자를 37$^{\circ}C$에서 10분간 배양하였다. 배양된 정자부유액은 단백원 무첨가배양액과 1:5로 희석하여 10분간 배양한 다음 3 ${\mu}\ell$를 10$\pm$2개의 난자를 들어있는 배양액 소적(30 ${\mu}\ell$)에 넣어서 정자와 난자의 결합을 유도하였다. 정자 주입 후 3시간 혹은 24시간째에 난자를 뽑아내어 세척하였으며, 도립현미경(100$\times$)에서 난자에 부착된 정자의 수를 세었다. 수정란을 이용한 정도관리를 위하여 과배란이 유도된 암컷은 수컷과 합사시켰으며, hCG 주사 16~18시간째에 전핵기의 1세포 수정란을 회수하였다. 단백질원의 종류에 대한 효과를 확인하기 위하여 OSBA를 실시한 결과, 수정 3시간째에 난자당 하나 이상의 정자가 부착된 난자의 비율은 BSA첨가군, 무첨가군, FBS 첨가군의 순으로 유의한 차이를 나타내었다(100% vs. 60.2% vs. 2.1%). 한편, BSA 첨가군에서 정자의 결합능력이 우수하였으나 FBS는 매우 유해하였으며 FBS의 농도가 5%까지는 증가함에 따라 유의한 차이를 나타내었다. 따라서 투명대에 정자가 부착에 있어서 단백원이 매우 중요한 역할을 하며, OSBA는 정자와 난자의 결합에 결정적인 영향을 미칠 수 있는 배양조건을 명확히 판별할 수 있음을 시사하였다. Met. II(mature)와 Met. I(intermediate mature) 난자를 단백원 무첨가, 15% FBS, 0.4% BSA 및 10% AF(양수)가 첨가된 Ham's F-10 배양액에서 OSBA를 실시한 결과, 난자의 성숙도에 상관없이 정자의 결합능력은 비슷한 양상을 보였으며, BSA첨가군, 양수첨가군, 무첨가군, FBS첨가군 순으로 높게 나타났다. 이러한 결과는 OSBA에서 Met. II 난자 대신에 Met. I난자를 이용해도 비슷한 결과를 얻을 수 있음을 시사한다. 생쥐 1세포기배에서 배반포까지의 배발달율을 기준으로 Ham's F-10배양액을 평가하여 일련번호 151은 불량(poor), 152는 양호(good)로 판정한 다음, 동일한 배양액에 OSBA를 실시한 결과 생쥐 1세포기배의 결과와 마찬가지로 일련번호 152 배양액이 151 배양액보다 유의하게 높게 나타났다. 따라서 OSBA는 기존의 정도관리 방법과 동일한 효과를 기대할 수 있을 것이다. 결론적으로, OSBA는 배양액 조건에 따라 정자의 결합능력이 다르다는 것을 보여주었으며, 정토관리 방법으로서의 유용성을 확인시켜 주었다. 또한 쉽게 준비할 수 있는 생쥐의 난자와 정자를 이용하였으며, 배양시간이 3시간으로 짧고, 평가방법이 간편해 시간적, 경제적으로도 효율성이 높다고 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권12호
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• pp.1718-1728
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• 2011

Two experiments were conducted to investigate the in vitro ability of keratinase to hydrolyze soybean glycinin and ${\beta}$-conglycinin and to evaluate the in vivo effects of keratinase when included in corn-soybean diets with different levels of crude protein and fed to nursery pigs. In experiment 1, a saturated keratinase solution (1 ml) was added to two blank controls of either glycinin or ${\beta}$-conglycinin resulting in the hydrolysis of 94.74% glycinin and 88.89% ${\beta}$-conglycinin. In experiment 2, 190 pigs (8.3${\pm}$0.63 kg BW) were allotted to one of four treatments in a 2${\times}$2 factorial arrangement on the basis of body weight, and sex was balanced among the pens. The effects of crude protein (19 vs. 22%) and keratinase (0 vs. 0.05%) were studied. Each treatment was applied to six pens with seven (two pens) or eight pigs per pen. Pigs were fed the experimental diets for 21 d. Weight gain and feed conversion ratio were improved (p<0.05) with keratinase supplementation while feed intake was reduced (p<0.05). Keratinase supplementation increased (p<0.05) the apparent total tract digestibility of dry matter, energy, crude protein and phosphorus. Keratinase supplementation also increased n-butyric acid in the cecum and colon, lactobacilli and total anaerobe counts in the colon as well as the ratio of villus height to crypt depth in the ileum. Additionally, fecal score, ammonia nitrogen and branch chain volatile fatty acids in the colon, E. coli and total aerobe counts in the colon, crypt depth in the jejunum and ileum as well as serum interleukin-1 and interleukin-6 concentrations were also decreased (p<0.05) by keratinase supplementation. A reduction in dietary crude protein decreased (p<0.05) colon ammonia nitrogen concentration and cecal propionic acid and branch chain volatile fatty acid concentrations. In addition, cecal E. coli counts, colon total anaerobe counts, ileal crypt depth, and serum interleukin-1 and interleukin-6 concentrations were also decreased (p<0.05) with the reduction of dietary crude protein. With the exception of fecal scores, there were no significant interactions between crude protein and keratinase. This study provides evidence that dietary keratinase supplementation improved nursery pig performance by improving intestinal morphology and ecology, thus improving nutrient digestibility and alleviating the inflammatory response.