• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.103-105
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• 2003

After fifteen years of development, Magnetic Resonance (MR) technology for human imaging and spectroscopy is reaching a refined state with FDA approved 3T clinical products from Siemens, GE, and Philips. Broker has cleared CE approval with a 4T system. Varian supports a 4T system platform as well. Shielded magnets are standard at 3T from GE, Oxford, Magnex, and IGC. A shielded 4T whole body magnet is available from Oxford. Stronger switched gradients and dynamic shim coils, desired at any field, areespecially useful at higher static magnetic fields B0. In addition to the higher currents required for higher resolution slice or volume selection afforded by higher SNR, whole body gradient coils will be driven at increasing slew rates to meet the needs of new cardiac applications and other requirements. For example 3T and 4T systems are now being equipped with 2kV, 500A gradient coils and amplifiers capable of generating 4G/cm in 200msec, over a 67+/-cm bore diameter. High field EPI applications require oscillation rates at 1 kHz and higher. To achieve a benchmark 0.2 ppm shim over a 30cm sphere in a high field magnet, at least four stages of shimming need to be considered. 1) A good high field magnet will be built to a homogeneity spec. falling in the range of 100 to 150 ppm over this 30cm spherical "sweet spot" 2) Most modern high field magnets will also have superconducting shim coils capable of finding 1.5 ppm by their adjustment during system installation. 3) Passive ferro-magnetic shimming combined with 4) active, high order room temperature shim coils (as many as five orders are now being recommended) will accomplish 0.2 ppm over the 30cm sphere, and 0.1 ppm over a human brain in even the highest field magnets for human studies. Safety concerns for strong, fast gradients at any B0 field include acoustic noise and peripheral nerve stimulation. One or more of the mechanical decoupling methods may lead to quieter gradients. Patient positioning relative to asymmetric or short gradient coils may limit peripheral nerve stimulation at higher slew rates. Gradient designs combining a short coil for local speed and strength with a longer coil for coverage are being developed for 3T systems. Local gradients give another approach to maximizing performance over a limited region while keeping within the physiologically imposed dB0/dt performance limits.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.136-141
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• 2012

Purpose : To investigate the pharmacologic modulation of motor task-dependent physiologic responses by antiplatelet agent, clopidogrel, during hand motor tasks in healthy subjects. Materials and Methods: Ten healthy, right-handed subjects underwent three functional magnetic resonance (fMRI) sessions: one before drug administration, one after high dose drug administration and one after reaching drug steady state. For the motor task fMRI, finger flexion-extension movements were performed. Blood oxygenation level dependent (BOLD) contrast was collected for each subject using a 3.0 T VHi (GE Healthcare, Milwaukee, USA) scanner. $T2^*$-weighted echo planar imaging was used for fMRI acquisition. The fMRI data processing and statistical analyses were carried out using SPM2. Results: Second-level analysis revealed significant increases in the extent of activation in the contralateral motor cortex including primary motor area (M1) after drug administration. The number of activated voxels in motor cortex was 173 without drug administration and the number increased to 1049 for high dose condition and 673 for steady-state condition respectively. However, there was no significant difference in the magnitude of BOLD signal change in terms of peak T value. Conclusion: The current results suggest that cerebral motor activity can be modulated by clopidogrel in healthy subjects and that fMRI is highly senstive to evidence such changes.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2153-2155
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• 2012

Objective: This study was to assess liver involvement in multiple myeloma with the aid of liver function tests. Materials and Methods: A hospital based retrospective study was undertaken using data retrieved of multiple myeloma from the register maintained in the Department of Biochemistry of the Manipal Teaching Hospital, Pokhara, Nepal between $1^{st}$ January, 2007 and $28^{th}$ February, 2012. We collected biomarkers of liver profiles including bilirubin (Total, Direct and Indirect), total protein, albumin, AG ratio, SGOT, SGPT, ALP, ${\gamma}GT$, LDH, ferritin, renal profile and hematological profile. Descriptive statistics and testing of hypothesis were used for the analysis using EPI INFO and SPSS 16 software. Results: Out of 37 cases of multiple myeloma, serum level of AST, ALT, ALP, ${\gamma}GT$ and LDH were increased above the cut-off point in 22 (59.5%), 24 (64.86%), 13 (35.13%), 9 (24.3%) and 11 (29.7%) respectively. The mean values of AST ($65.5{\pm}28.18$ U/L), ALT ($68.37{\pm}29.74$ U/L), ALP ($328.0{\pm}148.4$ U/L), ${\gamma}GT$ ($44.5{\pm}29.6$ U/L) and LDH ($361.7{\pm}116.5$ U/L), total protein ($9.79{\pm}1.03$ gm/dl) were significantly increased when compared with controls. In contrast, albumin ($3.68{\pm}0.43$ gm/dl) and the AG ratio ($0.62{\pm}0.15$) were significantly decreased. Similarly, anemia, hyperuricemia, azotemia, hypercalcaemia and Bence Jones proteinuria were found in 30 (78.9%), 27 (71.1%), 19 (51.5%), 15 (39.5%) and 16 (42.1%) respectively, in cases of multiple myeloma. Conclusions: While clinical manifestation of liver disease among the multiple myeloma was not common, abnormalities in liver function were characteristic.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.3131-3137
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• 2013

Background: Visual inspection of cervix with acetic acid (VIA) is offered at 252 centers in 64 districts of Bangladesh. VIA+ve women are managed at colposcopy clinics of Bangabandhu Sheikh Mujib Medical University (BSMMU) and 14 Medical College Hospitals (MCHs). This research work has been supported by 'UICC Cancer Prevention Campaign' programme. Objectives: This study explored the role of print materials and electronic media to improve cervical cancer screening in the present socio-cultural context of Bangladesh. Methods: This study was performed from January to August 2011 at two upazilas of Bangladesh (Singair with screening facility and Sonargaon without screening facility). Data were collected by focus group discussion (FGD) with women, husbands and community people before and after intervention. Information on cervical cancer screening and VIA camps was disseminated using advertisement through local cable line of the television, microphone announcement, service providers and leaflet throughout the week prior to a VIA camp. Three-day VIA camps were organized at the upazila health complex (UHC) of both upazilas. Quantitative data was gathered from women at the camps on source of information on VIA and the best method of awareness creation. Results: The population was aware of "cancer" and a notable number knew about cervical cancer. Baseline awareness on prevention and VIA was low and it was negligible where screening services were unavailable. Awareness was increased fourfold in both upazilas after interventions and half of the women and the majority of the community people became aware of screening and available facilities. Cable line advertisement (25.5%), microphone announcement (21.4%), and discussion sessions (20.4%) were effective for awareness creation on VIA. Television was mentioned as the best method (37.4%) of awareness creation. Conclusion: Television should be used for nation-wide awareness creation. For local awareness creation, cable line advertisement, microphone announcements and health education at Uthan Baithaks/ EPI sessions can easily be adopted by the government.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.183-194
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• 1992

Some silicon micromechanical structures useful in sensors and actuators have been fabricated by electropolishing or porous silicon formation technique by anodic reaction in HF solution. The microstructures were lightly doped single crystal silicon and the formation was isotropic independent of crystal directions. Porous silicon layer(PSL) was formed selectively in $n^{+}$ region of $n^{+}/n$ silicon structure by anodic reaction in concentrated HF(20-48%) solution. Characteristics of the formed PSL were investigated along with change of the reaction voltage, HF concentration and the reaction time. PSL was formed only in $n^{+}$ region. The porosity of the PSL was decreased with the increase of HF concentration and independent of reaction voltage. For the case of $n/n^{+}/n$ structures, the etched surface of silicon was fairly smooth and a cusp was not found. The thickness of the microstructures was the same as that of the epitaxial n-Si layer and good uniformity. We have fabricated acceleration sensors by anodic reaction in HF solution(5 wt%) and planar technology. The process was compatible with conventional It fabrication technique. Various micromechanical structures, such as rotors of motor, gears and linear actuator, were also fabricated by the technique and examined by SEM photographs.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.235-239
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• 2003

Thirteen sesquiterpene lactones isolated from the flower of Chrysanthemum coronarium L., which has been widely cultivated in Korea as a vegetable for a long time, were investigated their antimicrobial activities against eight bacteria and five phytopathogenic fungi. The antimicrobial activities of dihydrochrysanolide (6) and 1-epi-dihydrochrysanolide (7) showed strong activities against all the bacteria such as Bacillus subtilis, Bacillus cereus, Staphylococcus aureus and Vibrio parahaemolyticus. Especially, Staphylococcus aureus was investigated that have very strong antibacterial activity to $1.56\;{\mu}g{\cdot}disc^{-1}$, respectively. Also, most of sesquiterpene lactones, which have ${\alpha}-methylene-{\gamma}-butyrolactone$ group, were exhibited strong activity to Gram(+) bacteria than Gram(-) bacteria. In the antifungal test, Rhizoctonia solani and Phytophthora capsici known as phytopathogenic fungi have exhibited all extensive activity about compounds that have ${\alpha}-methylene-{\gamma}-butyrolactone$ group.

• Environmental and Resource Economics Review
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• v.16 no.3
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• pp.549-574
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• 2007

This paper was intended to evaluate environmental policies of South Korea and compare its environmental sustainability with other Eastern Asian countries in terms of some sustainability measures. To meet the purpose, the paper is composed of three parts: a brief and critical review of Korea's current environmental policies, comparison of its sustainability with other Eastern Asian countries in terms of well-known environmental sustainability indices, and comparison in terms of a less well-known alternative measure. Korea's environmental policies as stipulated in "Green Vision 21", "Green Korea 2005" were evaluated in light of OECD EPRK 2006. Korea's environmental performance is then compared with other countries based on such environmental sustainability indices as EF, ESI, EPI and EVI. Unfortunately the well-publicized indices to measure sustainable development (SD) seem to fail in measunng SD and in providing comparability, because it does not base on the genuine concept of SD. Therefore, we tried to suggest an alternative measurement in terms of sustainability quantity (SQ), which is presented for South Korea and her major trading partners, such as USA, Japan and China.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1777-1783
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• 2014

In this paper, we designed and fabricated a high-speed semiconductor sensor for use in power control devices and analyzed the characteristics with pulsed radiation tests. At first, radiation sensitive circular Si PIN diodes with various diameters(0.1 mm ~5.0 mm) were designed and fabricated using Si epitaxial wafer, which has a $42{\mu}m$ thick intrinsic layer. The reverse leakage current of the diode with a radius of 2 mm at a reverse bias of 30 V was about 20.4 nA. To investigate the characteristic responses of the developed diodes, the pulsed gamma-radiation tests were performed with the intensity of 4.88E8 rad(Si)/sec. From the test results showing that the output currents and the rising speeds have a linear relationship with the area of the sensors, we decided that the optimal condition took place at a 2 mm diameter. Next, for the selected 2 mm diodes, dose rate tests with a range of 2.47E8 rad(Si)/sec to 6.21E8 rad(Si)/sec were performed. From the results, which showed linear characteristics with the radiation intensity, a large amount of photocurrent over 60mA, and a high speed response under 350ns without saturation, we can conclude that the our developed PIN diode can be a good candidate for the sensor of power control devices.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.133-133
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• 2002

Purpose： The purpose of paper is to implement software to visualize brain fiber tract using a 24-bit color coding scheme and to test its feasibility. Materials and Methods： MR imaging was performed on GE 1.5 T Signa scanner. For diffusion tensor image, we used a single shot spin-echo EPI sequence with 7 non-colinear pulsed-field gradient directions： (x, y, z)：(1,1,0),(-1,1,0),(1,0,1),(-1,0,1),(0,1,1),(0,1,-1) and without diffusion gradient. B-factor was 500 sec/$\textrm{mm}^2$. Acquisition parameters are as follows： TUTE=10000ms/99ms, FOV=240mm, matrix=128${\times}$128, slice thickness/gap=6mm/0mm, total slice number=30. Subjects consisted of 10 normal young volunteers (age：21∼26 yrs, 5 men, 5 women). All DTI images were smoothed with Gaussian kernel with the FWHM of 2 pixels. Color coding schemes for visualization of directional information was as follows. HSV(Hue, Saturation, Value) color system is appropriate for assigning RGB(Red, Green, and Blue) value for every different directions because of its volumetric directional expression. Each of HSV are assigned due to (r,$\theta$,${\Phi}$) in spherical coordinate. HSV calculated by this way can be transformed into RGB color system by general HSV to RGB conversion formula. Symmetry schemes： It is natural to code the antipodal direction to be same color(antipodal symmetry). So even with no symmetry scheme, the antipodal symmetry must be included. With no symmetry scheme, we can assign every different colors for every different orientation.(H =${\Phi}$, S=2$\theta$/$\pi$, V=λw, where λw is anisotropy). But that may assign very discontinuous color even between adjacent yokels. On the other hand, Full symmetry or absolute value scheme includes symmetry for 180$^{\circ}$ rotation about xy-plane of color coordinate (rotational symmetry) and for both hemisphere (mirror symmetry). In absolute value scheme, each of RGB value can be expressed as follows. R=λw｜Vx｜, G=λw｜Vy｜, B=λw｜Vz｜, where (Vx, Vy, Vz) is eigenvector corresponding to the largest eigenvalue of diffusion tensor. With applying full symmetry or absolute value scheme, we can get more continuous color coding at the expense of coding same color for symmetric direction. For better visualization of fiber tract directions, Gamma and brightness correction had done. All of these implementations were done on the IDL 5.4 platform.

• Investigative Magnetic Resonance Imaging
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• v.14 no.2
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• pp.115-120
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• 2010

Purpose : To separate and evaluate the low frequency spontaneous fluctuation BOLD signals from the functional magnetic resonance imaging data using sensorimotor active task. Materials and Methods : Twenty female archery players and twenty three control subjects were included in this study. Finger-tapping task consisted of three cycles of right finger tapping, with a subsequent 30 second rest. Blood oxygenation level-dependent (BOLD) data were collected using $T2^*$-weighted echo planar imaging at a 3.0 T scanner. A 3-D FSPGR T1-weighted images were used for structural reference. Image processing and statistical analyses were performed using SPM5 for active finger-tapping task and GIFT program was used for statistical analyses of low frequency spontaneous fluctuation BOLD signal. Results : Both groups showed the activation in the left primary motor cortex and supplemental motor area and in the right cerebellum for right finger-tapping task. ICA analysis using GIFT revealed independent components corresponding to contralateral and ipsilateral sensorimotor network and cognitive-related neural network. Conclusion : The current study demonstrated that the low frequency spontaneous fluctuation BOLD signals can be separated from the fMRI data using finger tapping paradigm. Also, it was found that these independent components correspond to spontaneous and coherent neural activity in the primary sensorimotor network and in the motor-cognitive network.