• Journal of Magnetics
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• 제8권4호
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• pp.129-132
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• 2003

We investigated the crystallographic and magnetic properties of double perovskite $Sr_2Fe_{l-x}Cr_{x}MoO_{6}$ (x=0.0, 0.01, 0.03, 0.05, and 0.10). Mossbauer spectra of the $Sr_2Fe_{l-x}Cr_{x}MoO_{6}$ have been taken at various temperatures ranging from 15 to 415 K. As the temperature increased towards $T_{c}$(415 K), the Mossbauer spectra showed line broadening and 1, 6 and 3, 4 line-width differences because of anisotropic hyperfine field fluctuation. The Mossbauer spectra indicated that an anisotropic field fluctuation of +H ( $P_{+}$=0.85) was greater than that of -H ($P_{-}$=0.15). We also calculated the field fluctuation frequency factors and the temperature dependence of anisotropy energies from its relaxation rate. We interpreted the effect of Cr ($t^3$$_{2g}$) doping as a decrease in the anisotropy energy.

• KSBB Journal
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• 제23권6호
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• pp.509-512
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• 2008

원료물질인 대두유를 산가수분해하여 지방산의 함량을 분석한 결과 linoleic acid, oleic acid, palmitic acid, stearic acid의 함량순으로 분석되었다. 동일한 조건하에 대두유의 가수분해반응 전화율을 조사한 결과 Candida rugosa와 Candida cylindracea 에서 유래된 효소인 CR-E와 CC-E가 Lipase 16, Novozyme 871과 Lipolase-100 L보다 2배이상 높았다. 따라서 CR-E와 CC-E를 선정하여 반응조건에 대한 실험을 수행하였다. CR-E와 CC-E의 경우 비슷한 결과를 보여, pH $3{\sim}6$, $35-45^{\circ}C$, 물과 대두유의 중량비가 3.3 이상이었을 때가 최적인 반응조건이었으며 95% 이상의 높은 전화율을 나타내었다.

• 한국자기공명학회논문지
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• 제8권1호
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• pp.28-36
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• 2004

Authors investigated whether there is a lateral effect of $^1$H MRS observable metabolite ratios between the symptomatic and the nonsymptomatic side in the early stage of Parkinson's disease with unilateral symptom. Localized in vivo $^1$H MR spectroscopy (MRS) was used to measure the metabolite levels in the symptomatic and the nonsymptomatic sides of the lentiform nucleus in Parkinson"s disease with unilateral symptom (N=25). The metabolite ratios of NAA/Cr and Cho/Cr in the symptomatic side were compared with those in the nonsymptomatic side. Significant metabolic lateral effect of NAA/(Cho+Cr) ratio was established between the symptomatic and the nonsymptomatic side of lentiform nucleus in Parkinson's disease with unilateral symptom (p<0.05). The ratio of NAA/(Cho+Cr) homolateral to the sympatomatic side of the patient is also lower than that of the control (P<0.05). On the basis of NAA/Cr ratios of lentiform nucleus between the symptomatic and the nonsymptomatic side, the present $^1$H MRS study shows a significant neuronal laterality in Parkinson's disease with unilateral symptom. In vivo $^1$H MRS may provide a diagnostic marker for neuronal dysfunction in Parkinson's disease with unilateral symptom.

• 한국산업보건학회지
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• 제4권2호
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• pp.189-197
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• 1994

Analytic methods for Cr(VI) level in industrial hygienic field were suggested by the National Institute for Occupational Safety and Health(NIOSH method 7600, 7604). There were growing needs for measurement of Cr(III) and Cr(VI) levels simultaneously. Two analytical methods were suggested to determine Cr(III) and Cr(VI) levels simultaneously. The one is method by using reversed phase high peformance liquid chromatography(HPLC) and the other is by using ion exchange HPLC. The purpose of this work was to evaluate the usefulness of these two analytic methods. For the difference of ionic charges of Cr(III)-ethylendiamine tetraacetic acid(EDTA) chelate and $CrO_4{^-2}$, we could detect them simultaneously by ion exchange HPLC. Also, we attempted to determine the levels of Cr(III) and Cr(VI) chelated with sodium diethyldithiocarbamate(NaDDTC) by using reversed phase HPLC. The confirmation of Cr(III) and Cr(VI) were checked by fraction collector and nameless atomic absorption spectrometer. The optimal conditions for the formation of Cr(III)-EDTA chelate were two hours incubation period with pH 5. Cr(III)-EDTA and Cr(VI) in EDTA solution were successfully separated by anion exchange column using $Na_2CO_3/NaOH$ mixture as mobile phase. Peaks of Cr(III)-EDTA and Cr(VI) in EDTA were identified at 5 minutes and 7 minutes of retention time respectively by the ion exchange HPLC. The formation of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were twelve hours incubation period. Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were separated by reversed phase column using methanol and water mixture as mobile phase. Peaks of Cr(VI)NaDDTC and Cr(III)-NaDDTC chelates were identified at 13 minutes and 26 minutes of retention time respectively by the reversed phase HPLC. Due to reduction of Cr(VI) to Cr(III), it seems to be not suitable for simultaneous determination of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates by reversed phase HPLS. Simultaneos determination of Cr(III) and Cr(VI) by ion exchange HPLC was more accurate and simple method.

• Investigative Magnetic Resonance Imaging
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• 제17권2호
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• pp.110-122
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• 2013

목적: 발목관절 VISTA 자기공명영상을 이용하여 지방억제를 한 것과 하지 않은 VISTA 사이에서 정량평가를 하며, 발목 인대의 traceability 차이를 알아보고자 하였다. 대상과 방법: SNR의 비교를 위해 팬텀과 한명의 자원자에서 자기공명영상을 촬영하였다. CR (contrast ratio)과 인대 traceability 비교를 위해 발목 관절의 외상 과거력이 없는 10명의 자원자에서 자기공명영상을 촬영하였다. 모든 자기공명영상은 VISTA를 이용하였고 3T에서 촬영하였다. 지방억제는 SPAIR (Spectral Attenuated Inversion Recovery) 기법을 이용하였다. SNR은 피검자가 있을 때와 피검자 없이 촬영한 것으로 구하였다. CR은 열개의 오른쪽 발목관절의 관절액-힘줄, 관절액-연골, 관절액-인대, 지방-힘줄, 지방-연골, 지방-인대의 신호강도를 얻어 구하였다. 두 명의 근골격계 영상의학과 의사가 지방억제를 한 것과 하지 않은 영상을 calcaneofibular ligament (CFL)을 포함한 7개의 발목관절 인대에 대해서 점수를 매겼다 (1, not traceable; 2, barely traceable; 3, adequately traceable; 4, excellently traceable). VISTA 와 VISTA SPAIR 사이에 CR을 비교하는 데는 Wilcoxon signed-rank test를 이용하였다. VISTA 와 VISTA SPAIR사이에 인대 traceability를 비교하는 데에는 Fisher's exact test와 Pearson's chi-squared test를 이용하였다. 결과: 정량평가의 SNR을 보면 지방억제를 하지 않은 영상에 비해 지방억제를 한 자원자의 골수에서 더 낮은 수치를 나타내었다. (7.65 versus [vs.] 36.64). 관절액, 연골, 근육에서는 두 연쇄간에 SNR의 차이가 없었다. 지방억제 VISTA는 관절액-인대 사이 CR만 더 나은 결과를 보여주었지만 (p=0.04) VISTA는 지방-힘줄, 지방-연골, 지방-인대 간에서 모두 더 나은 CR값을 나타내었다(P=0.005). CFL 인대만 통계학적으로 의미 있는 값을 보였는데 지방억제를 하지 않은 VISTA 영상에서 traceability의 값이 더 우세 하였다(p <0.05). 결론: 지방 억제를 한 VISTA와 하지 않은 VISTA에서 유의한 SNR 차이는 골수를 제외하고 없었다. 지방억제를 하지 않은 VISTA에서 CFL을 trace하는데 있어서 더 유리하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7975-7979
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• 2015

Purpose: This study aimed to explore the value of IHC4 in predicting pathological response after neoadjuvant chemotherapy in patients with hormonal receptor (HR)-positive breast cancer (BC). Materials and Methods: In this retrospective exploratory study, data for 68 HR-positive BC patients who received neoadjuvant chemotherapy were recorded. IHC4 scores were calculated based on estrogen receptors/progesterone receptors, Ki-67 and HER2 status. Logistic and ordinal regression analyses in addition to likelihood ratio test were used to explore associations of IHC4 scores and other clinico-pathological parameters with pathological complete response (pCR) and pathological stage. Results: Taking the 25th percentile as the cut-off, a lower IHC4 score was associated with an increased probability of pCR (low; 52.9% vs. High; 21.6%, OR=4.1, 95% CI=1.28-13.16, p=0.018) and a lower pathological stage (OR=3.9, 95% CI=1.34-11.33, p=0.012). When the IHC4 score was treated as a continuous variable, a lower score was again associated with an increased probability of pCR (OR=1.010, 95% CI=1.001-1.018, p=0.025) and lower pathological stage (OR=1.009, 95% CI=1.002-1.017, P=0.008). Lower clinical stage was associated with a better pCR rate that was of borderline significance (P=0.056). When clinical stage and IHC4 score were incorporated together in a logistic model, the likelihood ratio test gave a P-value of 0.004 after removal of the IHC4 score and 0.011 after removal of the stage, indicating a more significant predictive value of the IHC4 score for pCR. Conclusions: This study suggests that the IHC4 score can predict pathological response to neoadjuvant chemotherapy in HR-positive BC patients. This finding now needs to be validated in a larger cohort of patients.

• 한국수산과학회지
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• 제50권1호
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• pp.1-7
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• 2017

The elimination of harmful heavy metals (Cd, Cr, and Pb) from sea lettuce Enteromorpha sp. was evaluated in filtered seawater over a pH range of 2.0-4.0 using citric, hydrochloric, and nitric acids. We also evaluated the quality of sea lettuce samples after release of their internal constituents into seawater solutions containing acids. The heavy metals that accumulated in raw sea lettuce after incubation for 3 days in seawater containing Cd, Cr, and Pb were, in descending order, Pb ($120.45{\mu}g/g$), Cr ($86.04{\mu}g/g$), and Cd ($18.35{\mu}g/g$). The rate of elimination of heavy metals from sea lettuce was higher at lower pH for all of the acids used. However, the color of the sea lettuce changed adversely at below pH 2.5. The heavy metals in sea lettuce samples after 10 min in seawater at pH 3.0 containing the three acids were eliminated in the order Pb (42.2-78.0%), Cd (51.8-55.3%), and Cr (14.0-32.8%). The quality of the sea lettuce was not affected when it was incubated for 30 min at pH above 3.0. The maximum elimination of heavy metals from sea lettuce occurred when it was soaked for 10 min in seawater at pH 3.0 containing citric acid.

• Nuclear Engineering and Technology
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• 제37권4호
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• pp.375-384
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• 2005

To investigate the flow-accelerated corrosion (FAC) dependency of carbon steel (A106 Gr. B) and low-alloy steels (1Cr-1/2Mo, 21/4Cr-1Mo) on pH, orifice distance, and material, experiments were carried out. These experiments were performed using a flow velocity of 4 m/sec (partly 9 m/sec) at pH $8.0\~10.0$ in an oxygen-free aqueous solution re-circulated in an Erosion-Corrosion Test Loop at $130^{\circ}\;{\ldots}$ for 500 hours. The weight loss of the carbon steel specimens appeared to be positively dependent on the flow velocity. That of the carbon and low-alloy steel specimens also showed to be distinguishably dependent on the pH. At pH levels of $8.0\~9.5$ it decreased, but increased from 9.5 to 10.0. Utility water chemistry personnel should carefully consider this kind of pH dependency to control the water system pH to mitigate FAC of the piping system material. The weight loss of the specimens located further from the orifice in the distance range of $6.8\~27.2$ mm was shown to be greater, except for 21/4Cr-1Mo, which showed no orifice distance dependency. Low alloy steel specimens exhibited a factor of two times better resistance to FAC than that of the carbon steel. Based on this kind of FAC dependency of the carbon and low-alloy steels on the orifice distance and material, we conclude that it is necessary to alternate the composition of the secondary piping system material of NPPs, using low-alloy steels, such as 21/4Cr-1Mo, particularly when the system piping has to be replaced.

• 농업과학연구
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• 제19권1호
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• pp.40-50
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• 1992

산효유제품(酸酵乳製品) 제조시(製造時) 유산균(乳酸菌) Starter의 산효성(酸酵性)을 촉진(促進)하기 위한 기초연구(基礎硏究)로서 Bulk medium에 Bios 2000, CR starter medium 및 Yeast extract를 각각(各各) 1.5%씩첨가(添加)하고 Lac. bulgaricus, Str. thermophilus 및 Lac. casei를 접종(接種) 배양(培養)하고 산도(酸度), pH 및 유산균수(乳酸菌數)의 변화(變化)를 조사(調査)한 결과(結果)는 다음과 같다. 1. Lactobacillus bulgaricus의 배양(培養)중 산(酸) 생성도(生成度)는 Control구(區)는 배양(培養) 16시간(時間)에 0.99%에 이르렀는데 비하여, CR starter mediurn 첨가구(添加區)는 배양(培養) 12시간(時間)에 1.0%이었고, Yeast extract 첨가구(添加區)는 배양(培養) 12시간(時間)에 1.12% 이였으며, Bios 200첨가구(添加區)는 배양(培養) 10시간(時間)만에 0.97%로써 가장 빠른 산생성도(酸生成度)를 보였다. 2. Lac bulgaricus의 배양(培養)중 pH의 변화(變化)는 Control구(區)는 배양(培養) 16시간(時間)에 4.03이였는데 반하여 Bios 2000 첨가구(添加區)는 배양(培養) 10시간(時間)에 4.10에 이르렀다. 또한, Yeast extract 첨가구(添加區)는 배양(培養) 12시간(時間)에 3.97, CR starter medium 첨가구(添加區)는 배양(培養) 12시간(時間)에 4.05를 나타내었다. 3. Lac. bulgaricus의 배양(培養)중 유산균수(乳酸菌數) 변화(變化)는 Control구(區)가 배양(培養) 16시간(時間)에 $3.1{\times}10^{10}/ml$이 되었는데 반하여 Bios 2000 첨가구(添加區)는 10시간(時間)에 $2.1{\times}10^{10}/ml$에 이르러 가장 빠른 생육(生育) 촉진현상(促進現狀)을 보였다. 한펀, CR starter medium 첨가구(添加區)는 12시간(時間)에 $2.9{\times}10^{10}/ml$, Yeast extract 첨가구(添加區)는 12시간(時間)에 $3.8{\times}10^{10}/ml$를 나타내었다. 4. Streptococcus thermophilus의 배양(培養)중 Acidlty 변화(變化)는 Control구(區)가 44시간(時間)만에 0.92%에 이르렀으며, CR starter medium 첨가구(添加區)는 40시간(時間)에 0.96%, Yeast extract 첨가구(添加區)는 32시간(時間)에 0.90% 이었다. 한편, Bios 2000 첨가구(添加區)는 32시간(時間)에 0.97%로 가장 높게 나타났다. 5. Str. thermophilus 배양(培養)중 pH 변화(變化)는 Control구(區)가 44시간(時間)에 4.27 이고, CR starter medium 첨가구(添加區)는 40시간(時間)에 4.33, Yeast extract 첨가구(添加區)는 32시간(時間)에 4.25이었다. 한편, Bios 2000 첨가구(添加區)는 32시간(時間)에 4.18로 가장 높게 나타났다. 6. Str. thermophilus의 배양(培養)중 유산균수(乳酸菌數) 변화(變化)는 Control구(區)가 44시간(時間)에 $9.8{\times}10^{9}/ml$이고, CR starter medium 첨가구(添加區)는 40시간(時間)에 $9.5{\times}10^{8}/ml$, Yeast extract 첨가구(添加區)는 32시간(時間)에 $9.6{\times}10^{8}/ml$이었다. 한편, Bios 2000 첨가구(添加區)는 32시간(時間)에 $2.0{\times}10^{9}/ml$로 가장 높게 나타났다. 7. Lactobacillus casei 균종(菌種)의 배양(培養) 중의 Acidity 변화(變化)는 Control구(區)가 40시간(時間)에 0.92%에 이르렀으며, CR starter medium 첨가구(添加區)는 40시간(時間)에 0.95%, Yeast extract 첨가구(添加區)는 36시간(時間)에 1.01%이었다. 한편, Bios 2000 첨가구(添加區)는 32시간(時間)에 0.94%로 가장 높게 나타났다. 8. Lac. casei 균종(菌種)의 배양(培養)중 pH 변화(變化)는 Control구(區)가 40시간(時間)에 4.27이고, CR starter medium 첨가구(添加區)는 40시간(時間)에 4.21, Yeast extract 첨가구(添加區)는 36시간(時間)에 4.15이었다. 한편, Bios 2000 첨가구(添加區)는 32시간(時間)에 4.23으로 가장 높게 나타났다. 9. Lac. casei균종(菌種)의 배양(培養)중 유산균수(乳酸菌數) 변화(變化)는 Control구(區)가 40시간(時間)에 $9.4{\times}10^{7}/ml$이고, CR starter medium 첨가구(添加區)는 40시간(時間)에 $1.1{\times}10^{8}/ml$, Yeast extract 첨가구(添加區)는 36시간(時間)에 $5.0{\times}10^{8}/ml$이었다. 한편, Bios 2000 첨가구(添加區)는 32시간(時間)에 $6.4{\times}10^{8}/ml$로 가장 높게 나타났다.

• 대한치과기공학회지
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• 제34권4호
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• pp.353-359
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• 2012

Purpose: The aim of this study measured and compared the marginal and internal fit of metal cores with two base metal alloy (Ni-Cr alloy(non-beryllium), Co-Cr alloy). Methods: Maxillary right first molar abutment fabricated by titanium was prepared for this study. Impressions(10ea) were made from titanium model, and study models were poured with improved dental stone. Wax cores of twenty were prepared for burn-out and casting. Ten wax cores cast Ni-Cr alloy(non-Be), and finally ten cast Co-Cr alloy. Marginal and internal fit of cores was evaluated using silicone replica technique and digital microscope(x160). The data were statistically analyzed with the independent samples t-test (${\alpha}$ <.05). Results: Mean(standard deviation, SD) marginal and internal fit total size of Ni-Cr alloy(non-Be) group was $73.3(14.4){\mu}m$ and of Co-Cr alloy group $65.6(17.4){\mu}m$. The marginal and internal fit total size of Ni-Cr alloy group(non-Be) was statistically significantly greater than that of Co-Cr alloy group (P=.004). Conclusion: Co-Cr alloy cores in this study had a better marginal fit than Ni-Cr alloy(non-Be) cores.