• Investigative Magnetic Resonance Imaging
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• v.14 no.2
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• pp.103-114
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• 2010

Purpose : To generate a Korean specific brain template, especially in patients with Alzheimer's disease (AD) by optimizing the voxel-based analysis. Materials and Methods : Three-dimensional T1-weighted images were obtained from 123 subjects who were 43 cognitively normal subjects and patients with 44 mild cognitive impairment (MCI) and 36 AD. The template and the corresponding aprior maps were created by using the matched pairs approach with considering differences of age, gender and differential diagnosis (DDX). We measured several characteristics in both our and the MNI templates, including in the ventricle size. Also, the fractions of gray matter and white matter voxels normalized by the total intracranial were evaluated. Results : The high resolution template and the corresponding aprior maps of gray matter, white matter (WM) and CSF were created with the voxel-size of $1{\times}1{\times}1\;mm$. Mean distance measures and the ventricle sizes differed between two templates. Our brain template had less gray matter and white matter areas than the MNI template. There were volume differences more in gray matter than in white matter. Conclusion : Gray matter and/or white matter integrity studies in populations of Korean elderly and patients with AD are needed to investigate with this template.

• Investigative Magnetic Resonance Imaging
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• v.17 no.3
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• pp.192-199
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• 2013

Purpose : To retrospectively evaluate the diagnostic performance of dynamic contrast-enhanced MR imaging (DCE-MRI) in detecting recurrent prostate cancer after HIFU of clinically localized cancer, as compared with T2-weighted imaging (T2WI). Materials and Methods: Twenty-six patients with increased prostate-specific antigen levels after HIFU were included in this study. All MR examinations were performed using T2WI and DCE-MRI, followed by transrectal ultrasound-guided biopsy. MRI and biopsy results were correlated in six prostate sectors. Residual or recurrent cancer after HIFU was defined as local tumor progression if biopsy results showed any cancer foci. Two independent readers interpreted the MR images. Results: Of 156 prostate sectors, 51 (33%) were positive for cancer in 17 patients. For detecting local tumor progression, the sensitivity of DCE-MRI and T2WI was 80% and 57% for reader 1 (P < 0.001) versus 84% and 61% for reader 2 (P < 0.001), respectively. The specificity and overall accuracy between DCE-MRI and T2WI showed no statistical difference in both readers (P > 0.05). Interobserver agreement of DCE-MRI and T2WI was moderate and fair, respectively. Conclusion: For detecting local tumor progression of prostate cancer after HIFU, DCE-MRI was more sensitive than T2WI, with less interobserver variability.

• Investigative Magnetic Resonance Imaging
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• v.17 no.3
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• pp.232-238
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• 2013

Purpose : We investigated the possible added value of magnetic resonance imaging (MR) in staging of malignant pleural mesothelioma (MPM) compared to computed tomography (CT). Materials and Methods: We retrospectively enrolled 20 patients (M;F = 14:6; mean age, 53.5 yrs) who diagnosed as MPM by histology and underwent CT and MR at initial evaluation from Jan 1997 to Dec 2012. Two radiologists performed clinical staging by using CT alone or MR alone in consensus. In patients underwent surgery (n = 13), we evaluated the diagnostic accuracy of CT and MR in terms of staging compared to surgical staging. In all patients, we compared clinical staging of CT only and CT with MR. Results: The diagnostic accuracy for T staging of CT only was 23.1% (3/13) and that of combined CT and MR was 38.5% (5/13), respectively. Among 13 patients underwent surgery, surgical stage was higher than combined CT and MR stage in 5 patients, but lower in 3 patients. CT only and combined CT and MR agreed in 85.0% (17/ 20). In cases of disagree (15.0%, 3/20), combined CT and MR showed higher stage than CT only. Conclusion: Combined CT and MR increases the diagnostic accuracy in staging of MPM compared to CT only and is important in determining the appropriate treatment in patients being considered for surgery.

• Journal of Mushroom
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• v.3 no.4
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• pp.140-144
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• 2005

This study was conducted to verify the cause of suppression symptom in mycelial growth during summer and to be able to establish a countermeasure. Cultivation of Flammulina velutipes was experimented with varying elapsed time of 0, 3, 6, 9 hours after mixing the sawdust media and two kinds of water temperature (normal water, $24^{\circ}C$ and cold water, $6^{\circ}C$) for mixing sawdust media. There were trends of increased media temperature from $24^{\circ}C$ to $31^{\circ}C$ and decreased pH from 6.5 to 5.2~5.6 with varying elapsed time from mixing the media to sterilization. Bacterial density also increased with bacterial density in Medium $24^{\circ}C$ being 1.9~4.1 times higher than that in Medium 6. Growth of F. velutipes was delayed with dual culture of bacteria isolated from sawdust media. Total nitrogen content of sawdust media was lowered by elapsed time from mixing the media to sterilization. The use of normal water($24^{\circ}C$) delayed mushroom growth by 1~2 days compared with that of cold water($6^{\circ}C$). Furthermore, mycelial growth of F. velutipes in the bottle cultivation ceased 9 hours after mixing the media. Primordia formation of F. velutipes was delayed by 1~3 days by elapsed time after mixing sawdust media, while fruit-body yield decreased by 7~12% 6 hours after mixing the media. Fruit-body yield was more stabilized with the use of cold water($6^{\circ}C$) than with that of normal water($24^{\circ}C$). Results showed that it is effective to use cold water as low as $6^{\circ}C$ in mixing media for F. velutipes cultivation, especially during summer when environmental temperature is high, high pressure sterilization after bottling work can prevent bacterial propagation in the media and can stabilize media ingredient.

• Journal of Mushroom
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• v.3 no.4
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• pp.133-139
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• 2005

Fruiting bodies of Cordyceps have been regarded as popular folk and effective medicines to treat human diseases such as asthma, bronchial and lung inflammation, and kidney disease. Cordyceps pruinosa (Clavicipitaceae; Hypocreales; Ascomycotina) has received special attention for medicinal purpose due to its various physiological activites. The nucleoside derivative N6-(2-hydroxyethyl) adenosine (HEA) isolated from it showed a $Ca^{2+}$ antagonistic effect and negative inotropic response. The artificial production of fruiting body of C. pruinosa has not been tried successfully yet by using living silkworm substrate. To develop techniques for the production of C. pruinosa stromata on a large scale, the infection of Bombyx mori with C. pruinosa and the growth characteristics of stroma of C. pruinosa were investigated. Also, studied about biological activities of fruiting body formed on silkworm. Infection rate of the silkworm pupae with C. pruinosa was the highest in injection inoculation. The formation of the fruiting body of C. pruinosa was quite good in the room controlled at $21{\sim}25^{\circ}C$, over 91% of relative humidity and over 1500 lx. Glucose concentration was high in the fruiting bodies of the silkworm pupae infected with C. pruinosa on a dry weight basis. The most abundant amino acid in the fruiting bodies was arginine and phenylalanine. The fruiting bodies of silkworm pupae infected with C. pruinosa was rich in oleic acid. The high amount of citric acid was found in the fruiting bodies of silkworm pupae infected with C. pruinosa.

• Journal of Mushroom
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• v.7 no.3
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• pp.130-134
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• 2009

To develop new white variety of Oyster mushroom, all white varieties which have been collected and kept in the lab were revived and screened their cultural characteristics. 84 intra-specific Oyster mushroom hybrids between the white-colored mutants Suhan and Wonhyeong were developed using hyphal anastomosis technique in 2007. The Po2007-63 ($2842-7{\times}0205-7$) was shown the best cultural characteristics, selected to be a new variety and named as 'Goni'. The new commercial strain, 'Goni' has white pilei and grows well under spring and autumn conditions in Korea. The fruiting bodies of 'Goni' are of an excellent quality in that not only the stipe is thick and long but also the pileus is small and hard. The optimum temperatures for mycelial growth and fruiting body development were $25-30^{\circ}C$ and $10-16^{\circ}C$, respectively. Time period required for the initiation of the first fruiting body is about 3 to 5 days depending on the temperatures. The shape of fruiting body is thin funnel shape. Fruiting body production per bottle was about $91{\pm}13$ g which is almost 97% quantity compared to that of other variety 'Miso'. Relatively low temperature incubation ($11^{\circ}C$) resulted in the development of better quality of 'Goni' mushrooms. When two different media including potato dextrose medium and mushroom complete medium were compared, the growth of mushroom were much faster in mushroom complete medium at $20-25^{\circ}C$, but not at $25^{\circ}C$. Similar results were observed with other variety 'Miso'. Analysis of the genetic characteristics of the new commercial strain 'Goni' showed a major DNA profile as that of the parental Suhan when primer URP 1 was used, but different to 'Miso' that was used as a control. When screens were performed with primer URP 2, DNA patterns were similar both to that of the parents and 'Miso'. This new variety of the white Oyster mushroom has a clean and fresh image that corresponds well to "health food". We therefore expect that this new strain will satisfy the consumers demand for variety and excellent mushrooms.

• Journal of Mushroom
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• v.7 no.3
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• pp.105-109
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• 2009

Ten to thirty percent of ginko leaf pomace(GLP) were added to pine sawdust to investigate mycelial growth. Mycelial growth on the medium with GLP was 86~101(mm/28 days) and was slower than that of the control without GLP as, 102(mm/28 days). Mycelial growth time on medium of sawdust with 10 to 20% GLP was similar to the control without GLP as 29 days but that on medium with 30% GLP was delayed for 2 days. The time of pinhead formations of sawdust with 10 to 20% GLP was 7 days, the growth time to harvest was 11 days. These results were similar to those of the control without GLP. The sizes of pileus of treatments with 10 to 30% GLP were tend to be smaller compared with the control. The length of stipe of 10% GLP treatment was 98mm which was longer than that of the control with 91mm. The thickness of stipes of 10 to 30% GLP treatments were 45 to 48mm which were tend to be thicker than that of the control with 45mm. The hardness of stipe were 35,062($g/cm^2$) to 4,1065($g/cm^2$)) which were harder than that of the control with 32,156($g/cm^2$)). GLP treatments seem to be favorable to store or distribute. Yields per volume of GLP added treatments were 88.7g to 95.6g, which was increased 3 to 12% compare to 85.8g of the control without GLP.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.12
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• pp.844-861
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• 2008

The papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during the year of 2007 have been reviewed. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro nano fluid, micropump and fuel cell. Traditional CFD was still popular and widely used in research and development. Studies about fans and pumps were performed in the field of fluid machinery. Characteristics of flow and fin shape optimization are studied in the field of piping system. (2) The research works on heat transfer have been reviewed in the field of heat transfer characteristics, heat exchangers, and desiccant cooling systems. The research on heat transfer characteristics includes thermal transport in pulse tubes, high temperature superconductors, ground heat exchangers, fuel cell stacks and ice slurry systems. For the heat 'exchangers, the research on pin-tube heat exchanger, plate heat exchanger, condensers and gas coolers has been cordially implemented. The research works on heat transfer augmenting tubes have been also reported. For the desiccant cooling systems, the studies on the design and operating conditions for desiccant rotors as well as performance index are noticeable. (3) In the field of refrigeration, many papers were presented on the air conditioning system using CO2 as a refrigerant. The issues on the two-stage compression, the oil selection, and the appropriate oil charge were treated. The subjects of alternative refrigerants were also studied steadily. Hydrocarbons, DME and their mixtures were considered and various heat transfer correlations were proposed. (4) Research papers have been reviewed in the field of building facilities by grouping into the researches on heat and cold sources, air conditioning and air cleaning, ventilation and fire research including tunnel ventilation, flow control of piping system, and sound research with drain system. Main focuses have been addressed to the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies were mostly focused on analyzing the indoor environment in various spaces like cars, old tombs, machine rooms, and etc. in an architectural environmental field. Moreover, subjects of various fields such as the evaluation of noise, thermal environment, indoor air quality and development of energy analysis program were researched by various methods of survey, simulation, and field experiment.

• Geophysics and Geophysical Exploration
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• v.11 no.2
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• pp.99-108
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• 2008

To extend our detailed knowledge for the Hwasan caldera, we carried out magnetotelluric (MT) survey, which is pretty sensitive to electrical property variation in both horizontal and vertical direction of subsurface, across the Hwasan caldera with the direction of EW. The 2-D inversion results of observed MT data lead to following conclusions. Firstly, the depth of the basin basement inferred by the MT inversion results matches well with that suggested by previous potential studies, but the basement resistivity seems fairly low when compared to that of general case. This feature might be related with the large-scaled, highly conductive layer beneath the Euisung Sub-basin suggested by the previous MT study. Secondly, the high resistivity zones reaching to 4000 $\Omega{\cdot}m$ are imaged around two external ring fault boundaries. These zones are thought of as the response of the rhyolitic dykes intruding along the ring fault, and in the previous gravity data correspond to relatively high density anomalies. Thirdly, low resistivity zone reaching to 200 $\Omega{\cdot}m$ is detected around a depth of 1km beneath the central part of the caldera, which has not been yet reported in korean geophysical literatures. If we take account of the evolution model of the Hwasan caldera, this zone is regarded as the past sedimentary layer that subsided during the period of forming external ring fault system. In addition, the relatively low density anomaly observed in the central part of the caldera may be attributed to this sedimentary layer.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.383-392
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• 2007

Karstic features and mining-related cavities not only lead to severe restrictions in land utilizations, but also constitute serious concern about geohazard and groundwater contamination. A microgravity survey was applied for detecting, mapping and monitoring karstic cavities in the test site at Muan prepared by KIGAM. The gravity data were collected using an AutoGrav CG-3 gravimeter at about 800 stations by 5 m interval along paddy paths. The density distribution beneath the profiles was drawn by two dimensional inversion based on the minimum support stabilizing functional, which generated better focused images of density discontinuities. We also imaged three dimensional density distribution by growing body inversion with solution from Euler deconvolution as a priori information. The density image showed that the cavities were dissolved, enlarged and connected into a cavity network system, which was supported by drill hole logs. A time-lapse microgravity was executed on the road in the test site for monitoring the change of the subsurface density distribution before and after grouting. The data were adjusted for reducing the effects due to the different condition of each survey, and inverted to density distributions. They show the change of density structure during the lapsed time, which implies the effects of grouting. This case history at the Muan test site showed that the microgravity with accuracy and precision of ${\mu}Gal$ is an effective and practical tool for detecting, mapping and monitoring the subsurface cavities.