• Investigative Magnetic Resonance Imaging
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• v.8 no.1
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• pp.24-31
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• 2004

Purpose : To know the differences of proton MR spectroscopic features between recurrent rectal cancer and fibrosis in post-operative period, and to evaluate the possibility to discriminate recurrent rectal cancer from post-operative fibrosis by analysis of proton MR spectra. Materials and Methods : We evaluated the proton MR spectra from 25 soft tissue masses in perirectal area that developed in post-operative period after operation for the resection of rectal cancer. Our series included 11 cases of recurrent rectal cancer and 14 of fibrotic mass. All cases of recurrent rectal cancer and post-operative fibrosis were confirmed by biopsy. We evaluated the spectra with an attention to the differences of pattern of the curves between recurrent rectal cancer and post-operative fibrosis. The ratio of peak area of all peaks at 1.6-4.1ppm to lipid (0.9-1.6ppm) [P (1.6-4.1ppm/P (0.9-1.6ppm)] was calculated in recurrent rectal cancer and post-operative fibrosis groups, and compared the results between these groups. We also evaluated the sensitivity and specificity for discriminating recurrent rectal cancer from post-operative fibrosis by analysis of $^1H-MRS$. Results : Proton MR spectra of post-operative fibrosis showed significantly diminished amount of lipids compared with that of recurrent rectal cancer. The ratio of P (1.6-4.1ppm)/P (0.9-1.6ppm) in post-operative fibrosis was much higher than that of recurrent rectal cancer with statistical significance (p < .05) due to decreased peak area of lipids. Mean (standard deviations of P (1.6-4.1ppm)/P (0.9-1.6ppm) in post-operative fibrosis and recurrent rectal cancer group were $2.71{\pm}1.48\;and\;0.29{\pm}0.11$, respectively. With a cut-off value of 0.6 for discriminating recurrent rectal cancer from post-operative fibrosis, both the sensitivity and specificity were $100\%$ (11/11, and 14/14). Conclusion : Recurrent rectal cancer and post-operative fibrosis can be distinguished from each other by analysis of proton MR spectroscopic features, and $^1H-MRS$ can be a new method for differential diagnosis between recurrent rectal cancer and post-operative fibrosis.

• Journal of the Korean institute of surface engineering
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• v.41 no.5
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• pp.181-188
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• 2008

A.C. impedance properties of HA/Ti compound layer coated Ti-30Ta-($3{\sim}15$)Nb alloys have been studied by electrochemical method. Ti-30Ta binary alloys contained 3, 7, 10 and 15 wt% Nb were manufactured by the vacuum furnace system. And then specimen was homogenized at $1000^{\circ}C$ for 24 hrs. The sample was cut and polished for corrosion test and coating. It was coated with HA/Ti compound layer by magnetron sputter. The non-coated and coated morphology of Ti alloy were analyzed by X-ray diffractometer (XRD), energy X-ray dispersive spectroscopy (EDX) and filed emission scanning electron microscope (FE-SEM). The corrosion behaviors were investigated using A.C. impedance test (PARSTAT 2273, USA) in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. Ti-30Ta-($3{\sim}15\;wt%$)Nb alloys showed the ${\alpha}+{\beta}$ phase, and $\beta$ phase peak was predominantly appeared in the case of increasingly Nb contents. The microstructures of Ti alloy were transformed from needle-like structure to equiaxed structure as Nb content increased. From the analysis of coating surface, HA/Ti composite surface uniformed coating layer with 750 nm thickness. The growth directions of film were (211), (112), (300) and (202) for HA/Ti composite coating on the surface after heat treatment at $550^{\circ}C$, whereas, the growth direction of film was (110) for Ti coating. The polarization resistance ($R_p$) of HA/Ti composite coated Ti-alloys were higher than those of the Ti and HA coated samples in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. Especially, corrosion resistance of Ti-Ta-Nb system increased as Nb content increased.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.2
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• pp.105-118
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• 2008

Shotcrete is one of the main support materials in tunnelling. Its bonding state on excavated rock surfaces controls the safety of the tunnel: De-bonding of shotcrete from an excavated surface decreases the safety of the tunnel. Meanwhile, the bonding state of shotcrete is affected by blasting during excavation at tunnel face as well as bench cut. Generally, the bonding state of shotcrete can be classified as void, de-bonded, or fully bonded. In this study, the state of the back-surface of shotcrete is investigated using impact-echo (IE) techniques. Numerical simulation of IE technique is performed with ABAQUS. Signals obtained from the IE simulations were analyzed at time, frequency, and time-frequency domains, respectively. Using an integrated active signal processing technique coupled with a Short-Time Fourier Transform (STFT) analysis, the bonding state of the shotcrete can be evaluated accurately. As the bonding state worsens, the amplitude of the first peak past the maximum amplitude in the time domain waveform and the maximum energy of the autospectral density are increasing. The resonance frequency becomes detectable and calculable and the contour in time-frequency domain has a long tail parallel to the time axis. Signal characteristics with respect to ground condition were obtained in case of fully bonded condition. As the ground condition worsens, the length of a long tail parallel to the time axis is lengthened and the contour is located in low frequency range under 10 kHz.

• The Korean Journal of Physiology
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• v.8 no.2
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• pp.67-74
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• 1974

The object of this research is aimed to determine the activity of adenyl cyclase in both skeletal muscle sarcolemma and fat cell ghost of epididymal adipose tissue isolated from rats exposed to cold for various length of time in an attempt to evaluate whether the tissue sensitivity to catecholamine is increased when rats are exposed to cold for long periods of time Methods: a)Animals: Albino rats ranging in weight from 150 to 200 gm were used throughout this study. For experimental purposes, the rats are divided into two groups: experimental animals were place4 in a cold room at $4^{\circ}C$, controls being kept at $25^{\circ}C$. At the end of 2, 4, 6, 12, and 16 weeks. exposure to cold the rats were used to measure the adenyl cyclase activity. b) Isolation of plasma membrane from skeletal muscle and adipose tissue: The Plasma membrane of skeletal muscle from hind limbs of rats are prepared by the method employed by Rosenthal et at. and fat cell ghost of epididymal adipose tissue of rats by the method employed by Rodbell. c) Adenyl cyclase assay: Adenyl cyclase activity were measured by the method employed by Marinetti et al. Briefly, plasma membrane was incubated with $3^H-ATP$, various amount of noradrenaline and other incubation mixture at $37^{\circ}C$ for 20 minutes. After stopping the enzyme reaction by immersion in boiling water, carrier 3',5'-AMP was added to the system as a marker and $100\;{\mu}1$ aliquots of incubation mixture were pipetted on $20{\time}20$ Whatman No. 3 MM filter paper for one dimensional chromatography. The cyclic AMP spots were cut off and placed in counting vials containing 10ml of Bray's scintillation cocktail. Radioactivity was determined with a Packard Tri-Carb liquid scintillation counter. The enzyme activity is expressed as nanomoles of cyclic AMP produced per mg of membrane per hour. Result: 1. Average adenyl cyclase activity in the plasma membrane of skeletal muscle before and after noradrenaline administration was significantly higher in the cold-exposed rats as compared to the control. Continuous exposure to cold Produced an increased adenyl cyclase activity before and after noradrenaline administration. Adenyl cyclase activity reached peak levels at the 6 weeks exposure to told and level of adenyl cyclase activity remained high. Noradrenaline administration to the incubation medium induced a significant increase in adenyl cyclase activity and the degree of stimulation were proportional to the hormonal concentration But the rate of inclement in adenyl cyclase activity by noradreasline was the same in both groups. 2. Adenyl cyclase activity in fat cell ghost between cold exposed and control rats showed no significant differences before and after noradreualine administration. In summary, it can be concluded that cold adaptation give rise an increased activity of adenyl cyclase in plasma membrane of skeletal muscle in rats.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.6
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• pp.253-266
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• 2020

The extended slip-weakening model was investigated by using a compiled set of source-spectrum-related parameters, i.e. seismic moment M_o, S-wave velocity V_s, corner-frequency f_c, and source-controlled high-cut frequency fmax, for 113 shallow crustal earthquakes (focal depth less than 25 km, M_W 3.0~7.5) that occurred in Japan from 1987 to 2016. The investigation was focused on the characteristics of stress drop, radiation energy-to-seismic moment ratio, radiation efficiency, and fracture energy release rate, G_c. The scaling relationships of those source parameters were also investigated and compared with those in previous studies, which were based on generally used singular models with the dimensionless numbers corresponding to f_c given by Brune and Madariaga. The results showed that the stress drop from the singular model with Madariaga's dimensionless number was equivalent to the breakdown stress drop, as well as Brune's effective stress, rather than to static stress drop as has been usually assumed. The scale dependence of stress drop showed a different tendency in accordance with the size category of the earthquakes, which may be divided into small-moderate earthquakes and moderate-large earthquakes by comparing to M_o = 10¹⁷~10¹⁸ Nm. The scale dependence was quite similar to that shown by Kanamori and Rivera. The scale dependence was not because of a poor dynamic range of recorded signals or missing data as asserted by Ide and Beroza, but rather it was because of the scale dependent V_r-induced local similarity of spectrum as shown in a previous study by the authors. The energy release rate G_c with respect to breakdown distance D_c from the extended slip-weakening model coincided with that given by Ellsworth and Beroza in a study on the rupture nucleation phase; and the empirical relationship given by Abercrombie and Rice can represent the results from the extended slip-weakening model, the results from laboratory stick-slip experiments by Ohnaka, and the results given by Ellsworth and Beroza simultaneously. Also the energy flux into the breakdown zone was well correlated with the breakdown stress drop, ${\tilde{e}}$ and peak slip velocity of the fault faces. Consequently, the investigation results indicate the appropriateness of the extended slip-weakening model.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.302-308
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• 1997

${\beta}-Cyclodextrin\;({\beta}-CD)$ polymers were prepared using epichlorohydrin as a cross linking agent. The polymers were separated into ${\beta}-CD$ soluble polymer $({\beta}-CD\;SP)$ and ${\beta}-CD$ insoluble polymer $({\beta}-CD\;ISP)$ on a 10,000 molecular weight cut-off membrane (YM 10). Optimum separation conditions in the YM 10 were: transmembrane pressure 51.7 kPa, separation temperature $35^{\circ}C$, and volume concentration ratio 10. The flux was $0.025\;mL/cm^{2}/min$ under the optimum conditions. Gel permeation chromatography indicated that ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$ had a degree of polymerization of $2{\sim}8$ and over 10, respectively. The formation of an inclusion complex with hydrophobic compounds such as 4-dimethylaminoazobenzene, methyl red, and naringin was compared among ${\beta}-CD,\;{\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. The molar absorptivity for the two chromatic compounds was increased and the absorption peak was shifted in the presence of ${\beta}-CD$ polymers. Naringin, the principal flavonoid bitter tasting component of citrus fruit, had a low water solubility. The solubility of naringin was increased through the formation of an inclusion complex with ${\beta}-CD$ polymers. There was no significant difference in the formation of an inclusion complex between ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. Reduction of the bitter components from citrus products was shown to be possible when employing ${\beta}-CD\;SP$, while the usage of ${\beta}-CD$ monomer has been limited due to the low water solubility.

• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.69-77
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• 2002

Margarite, which occurs in the Unkyori Formation of Miwon area, Chungcheongbukdo, South Korea, was investigated using the petrographic microscope, back-scattered electron images (BSEI), and electron probe microanalyzer (EPMA) to characterize the alteration textures and mineral chemistries. Most margarite crystals are inhomogeneous, and chlorite was commonly observed to occur at the boundaries parallel to the rim of margarite. Cracks occur across the basal plane of the margarite, and margarite is partly replaced by chlorite along the cracks. In additon, muscovite and biotite are intergrown in margarite and chlorite crystals, suggesting that margarite was partially altered to chlorite as well as to muscovite and biotite. Chemical analysis data show that paragonite solid solution in the margarite is approximately 19.6 mol%, but clintonite solid solution is negligible. Margarite crystals in the Unkyori Formation cut or penetrate other metamorphic minerals In the same thin sections and are oriented randomly without any relationship with the foliation of host rocks, indicating that formed as a secondary mineral after peak metamorphism. Furthermore, it seems that hydrothermal fluids associated with the Mesozoic intrusions developed near the sample are closely related to the margarite formation.

• The Korean Journal of Nuclear Medicine
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• v.26 no.1
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• pp.40-48
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• 1992

Gated blood pool scan is frequently used for evaluating the change in cardiac function in various cardiac diseases. But resting gated blood pool scan using only LVEF as a cardiac index has been consitently shown to have a low sensitivity, which is about 50%, in detecting coronary artery disease. So it is recommended to compare exercise gated blood pool scan to resting gated blood pool scan. Exercise tests, however, are not always possible, especially in patients with musculoskeletal diseases, recent myocardial infarction and in elderly persons. We studied the usefulness of resting gated blood pool scan using multiple indices in evaluating the patients with coronary artery disease. Studied cases were 185 patients with coronary artery disease (angina pectoris 31, myocardial infarction 154) and 25 normals with low likelihood of coronary artery disease. We used $^{99m}Tc-labeled$ RBC, 740 MBq labeled by in vivo method. The data were evaluated by Micro DELTA computer program. The results were as following: 1) The ejection rates (PER, AER) and filling rates (PFR, AFR) were different in normls and patients with angina pectoris or myocardial infarction. 2) Mean phase angle, ejection rates and filling rates could separate normals from coronary artery disease patients with normal LVEF. 3) Regional ejection fraction was decreased at the site of the infarct in patients with myocardial infarction. 4) Peak filling rate was the the most detectable index in evaluation of cardiac function in patients with coronary artery disease. 5) The threshold at 1.5 standard deviation of normal range was considered as the most reliable cut-off value from ROC analysis. These data suggest that the resting gated blood pool scan has an important role in the evaluation of cardiac functional changes using various cardiac indices in patients with coronary artery disease.

• Journal of Chest Surgery
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• v.12 no.4
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• pp.324-335
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• 1979

During the period of 4 years from August 1975 to August 1979 one hundred and forty seven cases of lung cancer were seen at Paik Foundation Hospital in Seoul, Korea. Among these 147 cases, 104 patients had primary carcinoma of the lung and the remainder was metastatic carcinoma to the lung. Among these 104 primary carcinoma patients, 73 cases were proven histologically as primary carcinoma of the lung. There were three cases of alveolar cell carcinoma [Table 1 ]. This clinical observation is based on those 73 cases including three case reports of the alveolar cell carcinoma. 1. Peak incidence was observed in the 5th decade of life. Male to female ratio was 2 to 1 [Fig. 1]. 2. Pathological classifications were as follows: epidermoid carcinoma, 24 cases [32.9%]; undifferentiated carcinoma, 20 cases [27.4%]; adenocarcinoma, 15 cases [20.5%]; bronchioloalveolar carcinoma [5.5%] and positive cytology, 10 cases [13.7%] [Fig. 2]. 3. Evidence of inoperability was observed in 55 patients [75% of the 73 cases] [Table 3]. 4. Among those 73 cases, operability was evaluated in 18 patients or 25%. One patient refused operation and 17 patients [23.6%] were explored. In 11 [15%] out of 17 patients, thoracotomies were performed. Six cases were pneumonectomies and 5 cases were lobectomies or bilobectomies [Fig. 3]. 5. First case of alveolar cell carcinoma was a 46 year-old housewife complaining of cough and hemoptysis for one year. The plain chest X-ray and bronchogram showed characteristic pictures as Figures 4 and 5. A pneumonectomy was carried out. Histologically, a beautiful alveolar carcinoma consisted of the characteristic tall columnar epithelial cells, which were lining the alveolar spaces as seen in Figures 6, 7, 8, and 20. 6. In the second case of 41 year old male, predominant clinical feature was single, well defined mass in the right lower lobe [Fig. 10 and 11] on chest X-ray. Bilobectomized specimen showed fragile, soft and hard tissue containing mucoid secretions and focal yellowish necrosis with pigmentation on cut surface [Fig. 12]. Slides showed tumor cells lined up along the alveolar septa with papillary projections [Fig. 13 and 14]. 7. Third case of alveolar cell carcinoma was a 50-year-old housewife with hemoptysis. An outstanding clinical picture was a round to lobulated mass in the right upper lobe [Fig. 16]. She is living now, 2 years and 1 month post-operatively, but has arrived at terminal stage with military nodular disseminations to the contralateral lung [Fig. 19].

• Analytical Science and Technology
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• v.7 no.3
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• pp.339-347
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• 1994

A multicolumn system consisted of two valve(10-port and 6-port valve)-three column (28% DC 200, SP 1700 and Chromosorb 102 column) was developed. Nine natural gas components composed of $N_2$, $CH_4$, $CO_2$, $C_2H_6$, $C_3H_8$, $i-C_4H_{10}$, $n-C_4H_{10}$, $i-C_5H_{12}$ 및 $n-C_5H_{12}$ completed all the baseline separation within 18 minutes. The accuracy and the precision of this system was tested. The retention times and the peak areas were determined with a repeatability between 0.02 and 0.16%, and less than 1%, respectively. Calibration curves for natural-gas components were plotted by the partial pressure injection method of pure gases, and good linear relationships for each component were presented. By using these calibration curves the accuracy of the multicolumn system compaired with that of the single column system for a certified standard gas of natural gas. As a result, relative error in the single and the multicolumn system was less than 0.5% and 0.04%, respectively. The result of application of this system in the analysis of importing LNG composition showed that the heating values calculated by the multicolum system were estimated lower compared with those calculated by the single column system and consequently, the importing price of LNG was able to be cut down.