• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.5
• /
• pp.347-353
• /
• 2008

Purpose: Cortical reorganization has an important role in the recovery of stroke. We analyzed the compensatory cerebral and cerebellar perfusion change in patients with unilateral cerebral infarction using statistical parametric mapping (SPM). Materials and Methods: Fifty seven $^{99m}TC-Ethylene$ Cystein Diethylester (ECD) cerebral perfusion SPECT images of 57 patients (male/female=38/19, mean age=$56{\pm}17\;years$) with unilateral cerebral infarction were evaluated retrospectively. Patients were divided into subgroups according to the location (left, right) and the onset (acute, chronic) of infarction. Each subgroup was compared with normal controls (male/female=11/1, mean age=$36{\pm}10\;years$) in a voxel-by-voxel manner (two sample t-test, p<0.001) using SPM. Results: All 4 subgroups showed hyperperfusion in the ipsilateral cerebral cortex, but not in the contralateral cerebral cortex. Chronic left and right infarction groups revealed hyperperfusion in the ipsilateral primary sensorimotor cortex, meanwhile, acute subgroups did not. Contralateral cerebellar hyperperfusion was also demonstrated in the chronic left infarction group. Conclusion: Using $^{99m}Tc-ECD$ SPECT, we observed ipsilateral cerebral and contralateral cerebeller hyperperfusion in patients with cerebral infarction. However, whether these findings are related to the recovery of cerebral functions should be further evaluated.

• Journal of Life Science
• /
• v.14 no.1
• /
• pp.141-147
• /
• 2004

In this study, we investigated the effect of Teminalia Chebula (TC) water extract on liver in Rat. Treatment of TC water extract was orally administered 200, 300 mg/kg daily for one week and two weeks. The clinical parameters of serum, values of AST, ALT showed significantly higher than in normal group. Xanthine oxidase and aldehyde oxidase activities were significantly increased comparison with normal group. Microsomal enzymes, aminopyrine N-demethylase and aniline hydroxylase were not affected. Water extract of TC also increased hepatic rnalondialdehyde formation and reduced glutathione content. We also found that water extract of TC decreased activities of glutathione S-transferase and glutathione reductase but was not affected activities of $\gamma$-glutamylcysteine synthetase Thus, it seems that the water extract of TC induced decrease of oxygen free radical scavenger, glutathione content by inhibition of glutathione reductase which may reform oxidized glutathione to reduced glutathione.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.49 no.2
• /
• pp.72-75
• /
• 2012

In this paper, high-efficiency DC-AC converter is implemented for the wireless power transmission. The DC-AC converter is implemented by combining the oscillator and power amplifier. Because the conversion efficiency of wireless power transmitter is strongly affected by the efficiency of power amplifier, the high-efficiency power amplifier is implemented by using the Class-E amplifier structure. Also, because the output power of oscillator connected to the input stage of power amplifier is low, high-gain two-stages power amplifier using the drive amplifier is implemented to realize the high-output power DC-AC converter. The dual band harmonic suppression filter is implemented to suppress 2nd, 3rd harmonics of 13.56 MHz. The output power and conversion efficiency of DC-AC converter are 40 dBm and 80.2 % at the operation frequency of 13.56 MHz.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.20 no.1
• /
• pp.59-65
• /
• 2016

Purpose Dynamic kidney scan is a typical imaging technique that visualizes kidney function. Reproducibility of dynamic kidney scans has been evaluated by comparing low-dose kidney scans with low-dose radiopharmaceutical and standard dynamic kidney scan. With this comparative study, if reproducibility is superb, the dynamic kidney scan method with reduced radioactivity to patients is to be utilized and radiation exposure to patient is to be reduced. Materials and Methods For gamma camera, Orbiter, SymbiaE (Siemens, Germany) was used. Among patients who had used 370 Mbq (10 mCi) from January of 2013 to February 2014 and other patients who had used 185 Mbq (5 mCi) from March of 2014 to July of 2015 with identical condition, 21 subjects using DTPA and 20 subjects using $MAG_3$, 41 subjects in total, had been selected as subjects for data. From renogram of the result image, frame of the peak point was selected. Then, region of interest of kidney and background had been selected and Kidney to Background Ratio has been calculated for comparison. Results In tests using DTPA, kidney to background ratio when using 370 Mbq was $5.67{\pm}0.8$ at average while it was $5.62{\pm}0.87$ when using 185 Mbq, which didn't show much difference. Also in the tests using $MAG_3$, kidney to background ratio when using 370 Mbq was $14.95{\pm}2.58$ at average and $14.56{\pm}2.02$ in 185 Mbq, which neither showed much difference. In paired sample t-test, p-value was 0.566 in DTPA and 0.363 in $MAG_3$, which confirmed that there was no difference between the groups. Conclusion In identical patients, when dose was decreased from 370 Mbq to 185 Mbq, reproducibility of dynamic kidney scan was proven to be excellent. Low-dose Dynamic kidney scan can achieve results with fine reproducibility without improvement in performance of gamma camera and is expected to reduce radiation exposure to patient.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.4
• /
• pp.45-50
• /
• 2004

In this paper, we present the low voltage and high efficiency Q-band MIMIC oscillator using device-level power combined structure. The oscillator was successfully integrated by using 0.1 ${\mu}{\textrm}{m}$ GaAs PHEMTS and the CPW transmission line. We show that the highest efficiency is 19 % with an output power of 2.6 ㏈m at a frequency of 34.56 ㎓. The operating voltage of the oscillator is 2.2 V which is lower voltage than that of previously reported oscillators at Q-band. And the maximum output power of 6.7 ㏈m was obtained at a frequency of 34.56 ㎓.

• Korean Journal of Veterinary Service
• /
• v.18 no.2
• /
• pp.113-123
• /
• 1995

The present study was conducted to investigate the prevalent characteristics of Fowl Typhoid and antibiotic susceptibility of Salmonella gallinarum isolated from 56 infective or dead chickens of 20 egg laying farms in Kyung Buk province during the period from August to December 1994. 1. Among 416, 000 chickens of 92 flocks in 20 egg laying farms, 17, 360 chickens of 31 flocks were died of Fowl Typhoid. 2. Salmonella gallinarum was isolated from 56 chickens in liver and spleen, and then blood of infective chickens was positive to Pullorum antigen. 3, In the survey of gross lesion of 56 chickens, 43 chickens(76.8%) were swelled at liver, 39(69.6%) were swelled at spleen, 12(21.4%) were changed with bronze, 3(5.4% ) were hemorrhagic in peritoneal cavity. 4. In transmission pattern, 4 farms were outbreaked the entrance of chicken house at first, but the others were outbreaked at various place. They were transmitted at right and left directions in flock. 5. 2 farms confirmed at the early stage of infection were eradicated by removing infective chickens and administrating antibiotics, but 18 farms at chronic stage were not. 6. The biochemical properties of 112 Salmonella gallinarum from chickens were generally identical to those of the referance, but H$_2$S was not productive, cellobiose was fermentive. 7 Minimum inhibitory concentration(MIC) of 20 isolates was performed by using 21 antibiotics, MICs of Amikacin(Ak), Gentamicin(Gm), Kanamycin(Km), and Tetracycline (Tc) were below 1.6 ug/ml, Ampicillin(Am), Furazolidone(Fu) and Neomycin(Nm) were below 3.1 ug/ml, Cephalothin(Ce), Cefazoline(Cf) and Chloramphenicol(Cm) were below 6.3 ug/ml, Nalidixic acid(Na), Polymyxin(Po) and Rifampicin(Rf) were below 12.5 ug/ml, Penicillin (Pm) was below 25 ug/ml, Colistin(Co) and Streptomycin(Sm) were below 50 ug/ml, Sulfamerazine(Sr) and Sulfamethazine (St) were below 200 ug/ml, Lincomycin(Lm) and Spiramycin(Sp) were below 400 ug/ml, Bacitracin(Ba) was below 800 ug/ml. 8. Among the 20 isolates, all(100%) of those were sensitive to Ak, Am, Ce, Cf, Cm, Fu, Gm, Km, Na, Nm, Po, Rf, Sr, St and Tc, but 6 isolates(30%) were resistent to Co, 20(100% ) to Ba, Lm, Pm, Sm, and Sp. The drug resistance patterns were simple which 6 strains were BaCoLmPmSmSp type, and 14 were BaLmPmSmSp type.

• The Korean Journal of Nuclear Medicine
• /
• v.28 no.1
• /
• pp.37-43
• /
• 1994

The coronary collateral vessels have revealed their significance in terms of reduction of infarct size, preservation left ventricular function, and prevention of left ventricular aneurysm in patients with myocardial infarction. The purpose of this study were to evaluated the relation between collateral circulation and $^{99m}Tc$-MIBI Heart SPECT in patient with acute myocardial infarction and their clinical significance. The fifty six MI patients with antegrade TIMI perfusion grade 0 and 1 were studied. The patients were classified into two groups; Group I inclueded 30 patients with grade 2, 3 Collateral flow. Group II inclueded 26 patients with grade 0, 1 Collateral flow. Collateral filling were graded from 0 to 3: 0- none, 1- Filling of side branch only, 2- Partial filling of the epicardial segment, 3- Complete filling of epicardial segment. Clinical variables, left ventricular function, $^{99m}Tc$-MIBI Heart SPECT were analyzed with angiographic finding. Results were following: 1) Collateral visualization was found to be greater in patient with involvement of right coronary artery (RCA). The collateral development site of infarct related artery was RCA 15 cases, left anterior descending artery (LAD) 10 cases, left circumflex artery (LCX) 5 cases, and the collateral circulation from LAD to RCA was 13 cases (40.6%). 2) There was a tendency to be decreased in peak CK activity with group I. 3) The presence of good collateral channels was more frequently $^{99m}Tc$-MIBI reversible perfusion defect (83.4% vs 15.3%, p<0.05). 4) No differences of left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), ejection fraction (EF) were noted between group I and group II. The presence of good collateral channels did affect the frequency of occurrence of $^{99m}Tc$-MIBI reversible perfusion defect.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.2
• /
• pp.90-94
• /
• 2011

In this paper, the energy transfer is associated with high frequency band and try to analysis the rectifier circuit structure and characteristics and find ways to maximum efficiency. Input signal at 13.56MHz is converted output DC signal with the experiments and measurements. Rectifier cirsuits can be divided into the half-wave, full-wave, bridge rectifier circuit. Research to the present with the passive components are carried out with a focus on efficiency improvements. Factors affecting the efficiency of rectification is dependent on the characteristics of the device. In this experiment, about 70% efficiency can be measured. By using an improved device for high efficiency could be obtained higher efficiency.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.2
• /
• pp.81-86
• /
• 2007

In this paper, the Power Added Efficiency (PAE) and linearity of class-F PA has been improved by using the PBG structure and the application of EER structure, simultaneously. The adaptive bias control circuit has been employed to improve the PAE through the application of EER structure. The PBG structure has been adapted for improving the Linearity by suppressing the harmonics on the output of amplifier. The PAE and the 3rd Inter-Modulation Distortion (IMD) has improved 34.56%, 10.66 dB, compared with those of the conventional Doherty amplifier, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.5
• /
• pp.162-167
• /
• 2009

In this paper, we present a compact Ultra-Wideband band-pass filter using a high-pass filter and low-pass filter. The structure of our proposed band-pass filter is very simple and the DGS(Defected Ground Structure) structure is used to get the low-pass filter characteristic. Our proposed band-pass filter can be much smaller than a cascaded filter. As a result of measurement the insertion loss is less than 0.5dB throughout the pass-band of $2.1GHz{\sim}10.56GHz$, the return loss is more than 20dB and the group delay maximum variation is 0.23ns from 0.12ns to 0.35ns.