• Korean Journal of Microbiology
• /
• v.26 no.1
• /
• pp.13-19
• /
• 1988

The location of R-determinants, $Ap^{r}$ and $Tc^{r}$, and replication origin in pKU41 determined using the construction of miniplasmid by the BamHI and the HindIII restriction fragment from pKU41 and the cloning of the restriction fragments from pKU41 into pSY343. The gene encoding resistance to ampicillin (Ap) as well as replication origin in pKU41 were located on the region overlapping BamHI B fragment and HindIII A fragment. The gene encoding resistance to tetracycline (Tc) was located on the region of the HindIII C fragment, which was cleaved by BamHI as well.

• Korean Journal of Veterinary Research
• /
• v.39 no.2
• /
• pp.327-337
• /
• 1999

The transposon TnphoA was used to generate avirulent mutants from a type A Pasteurella multocida. A suicide vector plasmid pRT733 carrying TnphoA, having the kanamycin resistant gene and harbored in Escherichia coli K-12 strain SM10(${\lambda}pir$), was mated with streptomycin resistant P. multocida P-1059 strain as recipient. This resulted in the generation of two TnphoA insertion mutants (transconjugants, tc95-a and tc95-b) which were resistant both to kanamycin ($Km^{R}$) and streptomycin ($Sm^{R}$), secreted alkaline phosphatase, and were avirulent to turkeys. Southern blot hybridization using two probes derived from internal fragments of TnphoA, confirmed the insertion of TnphoA into 12.9kb or 13.7kb DNA fragment from the EcoRV digested genomic fragments of transconjugants. The two transconjugants, tc95-a and tc95-b, were distinguishable from their parent strains by differences in ribotypes, and outer membrane protein profiles. TnphoA insertion in both transconjugants also resulted in constitutive expression of a 33Kd iron regulated outer membrane protein (IROMP). The gene encoding $Sm^{R}$ was also located within the same 12.9kb EcoRV genomic fragment from both transconjugants. Furthermore, our finding that the recipient P. multocida P-1059 $Sm^{R}$ strain and both transconjugants were avirulent to turkeys suggest that the either 12.9kb or 13.7kb genomic DNA contains the virulence gene and speculate that the presence of $Sm^{R}$ gene or TnphoA insertion may be responsible for regulating and inactivating the gene(s) encoding virulence in P. multocida.

• Journal of Sensor Science and Technology
• /
• v.10 no.3
• /
• pp.196-206
• /
• 2001

Real temperature profiles of a planar chromel-alumel mutli-junction thermal converter(TC 1) were measured by thermal image. Temperature profiles as a function of input power of thermal converters(TC 1${\sim}$TC 6) were simulated by 3-dimensional ANSYS program based on finite element method. Temperature difference between the hot junction and the cold junction for TC 1 was smallest and largest for TC 6 and correspondingly, he voltage response for TC 1 and TC 6 showed the smallest value of 3.09 mV/mW and the largest value of 4.03 mV/mW, respectively.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.22 no.2
• /
• pp.88-91
• /
• 2018

Purpose The purpose of this study is to investigate the simultaneous dual isotope (SDI) myocardial perfusion scan that can be performed in a short time using a semiconductor gamma camera. Materials and Methods Of the 86 patients who underwent Rest/Stress $^{99m}TC$-sestaMIBI 1-day myocardial perfusion scan and Rest $^{99m}TC$-sestaMIBI/Stress $^{201}Tl$ simultaneous dual isotope myocardial perfusion scan using a heart-only gamma camera, the test results were the same, 36 patients who did not show any change in the clinical outcome. Quantitative values were statistically analyzed using a QPS program to confirm the correlation between the images of the two examinations. Results Rest/Stress $^{99m}TC$-sestaMIBI simultaneous dual myocardial perfusion scans and $^{99m}TC$-sestaMIBI/Stress $^{201}Tl$ double-isotope myocardial perfusion scans were analyzed for Summed score. The $R^2$ value of the Rest summed score (RSS) was 0.91 and the $R^2$ value of the stress summed score (SSS) was 0.71. Conclusion The $^{99m}TC$-sestaMIBI/Stress $^{201}Tl$ simultaneous dual isotope scan confirmed its correlation with the previous day's test. The $^{99m}TC$-sestaMIBI/Stress $^{201}Tl$ simultaneous dual isotope scan can be completed in approximately 30minutes. It maybe clinically useful for patients who need short examination time such as emergency patients or elderly patients.

• The Journal of the Korean Society for Microbiology
• /
• v.21 no.4
• /
• pp.461-471
• /
• 1986

Shigella strains isloated in the Teagu area during the period from 1973 to 1985 were studied for species distribution, drug resistance, and R plasmids. Approximately 1,200 strains were isolated during this period, and most of them were classified into Shigella flexneri, S. sonnei occupied less than 20%, and S. dysenteriae and S. boydii were very rarely isolated. More than 95% of them were resistant to one or more of these drugs; chloramphenicol (Cm), tetracycline (Tc), streptomycin (Sm), sulfisomidine (Su), ampicillin (Ap), and trimethoprim (Tp). Strains resistant to kanamycin, nalidixic acid (Na), and rifampin (Rf) were rare, and no strain was resistant to cephaloridine, gentamicin, and amikacin. Approximately half of the isolates were resistant to drugs in 1973, but the rate of resistant strains increased to more than 95% from 1977. Strains resistant to the four drugs (Cm, Tc, Sm, and Su) occupied the majority of resistant strains until 1977, but the most prevalent multiplicity of drug resistance increased to six drugs (Cm, Tc, Sm, Su, Ap, and Tp) from 1978 with the marked increase of Ap- and Tp-resistant strains. Approximately 75% of them transferred resistance to Escherichia coli by conjugation, and the resistance was considered to be mediated by R plasmids. Almost all of them transferred the complete patterns of resistance to drugs except Na and Rf. However, among some strains of recent isolates, small numbers of segregants of transferred resistance were observed. The R plasmids in Shigella were mostly classified into Inc FII, and only small numbers into Inc B. Segregants were in most cases unclassified.

• The Korean Journal of Nuclear Medicine
• /
• v.33 no.1
• /
• pp.100-109
• /
• 1999

Purpose: Preamplifier and amplifier are very important parts for developing a portable counting or imaging gamma probe. They can be used for analyzing pulses containing energy and position information for the emitted radiations. The commercial Nuclear Instrument Modules (NIMs) can be used for processing these pulses. However, it may be improper to use NIMs in developing a portable gamma probe, because of its size and high price. The purpose of this study was to develop both preamplifier and amplifier and measure their performance characteristics. Materials and Methods: The preamplifier and amplifier were designed as a charge sensitive device and a capacitor resistor-resistor capacitor (CR-RC) electronic circuit, respectively, and they were mounted on a print circuit board (PCB). We acquired and analyzed energy spectra for Tc-99m and Cs-137 using both PCB and NIMs. Multichannel analyzer (Accuspec/A, Canberra Industries Inc., Meriden Connecticut, U.S.A) and scintillation detectors (EP-047(Bicron Saint-Gobain/Norton Industrial EP-047 (Ceramics Co., Ohio, U.S.A) with $2"{\times}2"$ NaI(T1) crystal and R1535 (Hamamatsu Photonics K.K., Electron Tube Center, Shizuoka-ken, Japan) with $1"{\times}1"$ NaI(T1) crystal were used for acquiring the energy spectra. Results: Using PCB, energy resolutions of EP-047 detectors for Tc-99m and Cs-137 were 12.92% and 5.01%, respectively, whereas R1535 showed 13.75% and 5.19% of energy resolution. Using the NIM devices, energy resolutions of EP-047 detector for Tc-99m and Cs-137 were measured as 14.6% and 7.58%, respectively. However, reliable energy spectrum of R1535 detector could not be acquired, since its photomultiplier tube (PMT) requires a specific type of preamplifier. Conclusion: We developed a special preamplifier and amplifier suitable for a small sized gamma probe that showed good energy resolutions independent of PMT types. The results indicate that the PCB can be used in developing both counting and imaging gamma probe.

• Korean Journal of Veterinary Research
• /
• v.17 no.2
• /
• pp.73-78
• /
• 1977

The distribution of coliform population and drug-resistant coliforms in Shinchun water during April to August in 1976 and R factors in resistant strains were studied. The mean coliform population in the stream water was 361 organisms per 0.1ml and 53.5% of total coliforms were fecal coliforms. Thritynine and a half percent of total coliforms were streptomycin (SM) resistant to one or more of following antibiotics; tetracycline (TC), chloramphenicol (CM), ampicillin (AP) and kanamycin (KM). The most frequent resistant pattern was triple resistance to SM, TC and AP (23.8%) and followed by quadruple one to SM, TC, CM and AP (17.5%). About 87 percent strains carried R factors which were transferable by conjugation to E. coli ML 1410 or S. typhimurium LT 2.

• 한국초전도학회:학술대회논문집
• /
• v.9
• /
• pp.38-42
• /
• 1999

We prepared hish T$_c$ Josephson junctions that have different I$_c\;'s$ and R$_n\;'s$ and studied their microwave properties. We measured the current-voltage characteristics of the junctions under the irradiation of 22 GHz electromagnetic wave at various temperatures. from the Shapiro steps, we calculated the maximum detectable frequency and the microwave received power of the junctions. Increasing critical current values increase both maximum detectable frequency and sensitivity. However, increasing temperature increase sensitivity but decrease maximum detectable frequency.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.35 no.3
• /
• pp.418-426
• /
• 2008

The objectives of this study were to examine the properties of fluoride-releasing resin composite restorative materials. Four commercially available compomer materials (Compoglass F: CF, $Dyract^{(R)}$ AP: DA, $Dyract^{(R)}$ flow: DF, F2000: FT) and one fluoride-releasing composite resin ($Tetric^{(R)}$ Ceram: TC) were selected as experimental materials. Rectangular-shaped tensile test specimens were fabricated in a teflon mold giving 5mm in gauge length and 2mm in thickness. Disk-shaped specimens were fabricated in the split teflon mold with diameter of 15mm and thickness of 1mm. After curing for an hour, specimens were immersed in deionized water at $37^{\circ}C{\pm}1^{\circ}C$ for 30 days. All specimens were thermocycled for 10,000 cycles with 15 seconds of dwelling time in each $5^{\circ}C$ and $55^{\circ}C$ water baths. Toothbrush abrasion test was conducted under a load of 1.5 N and the abraded surfaces were examined with surface roughness tester (SV-3000, Mitutoyo Co, Japan) and SEM (JSM-5800, JEOL, Japan). Fluoride recharging was done by toothbrushing for 3 min. using a fluoride toothpaste (Perio Alpine Herb, LG Household & Health Care, Korea). The results obtained were summarized as follows; 1. The highest tensile strength value of 32.3 MPa was observed in TC group and the lowest value of 16.8 MPa was observed in CF group. The tensile strength of TC group was significantly higher than those of CF and DF groups (P<0.05). 2. The lowest Ra value of 0.287 was observed in TC group and the highest value of 1.516 was observed in FT group. The Ra value of FT group was significantly higher than other groups (P<0.05). 3. The abraded surfaces revealed the increase of surface roughness due to the protrusion and missing of filler particles. 4. The release of fluoride of compomers after tooth brushing by Perio Alpine Herb was initially large and then followed by small and continuously. But it remains small and constant in fluoride-releasing composite resin of TC. 5. The highest value of fluoride release after toothbrushing by Perio Alpine Herb was $2.064{\mu}g/cm^2$ in CF group and the lowest value was $0.1119{\mu}g/cm^2$ in TC group. The amount of fluoride release of CF group was significantly higher than other groups (P<0.05).

• Korean Journal of Veterinary Research
• /
• v.48 no.3
• /
• pp.295-303
• /
• 2008

One hundred and sixty nine Escherichia (E.) coli strains isolated from fecal samples of aquatic birds in Geumho river basin and Dalseong park were tested by agar dilution method to determine their susceptibility patterns to 14 antimicrobial agents. The distribution of tetracycline resistance determinants (tetA, tetB, tetC, tetD and tetE) were also examined by PCR in 76 tetracycline-resistant ($TC^r$) E. coli isolates. The high resistance was observed in tetracycline, cephalothin and ampicillin (45.0~36.7%). Resistance of E. coli isolates derived from Dalseong park to tetracycline, cephalothin, ampicillin and streptomycin (65.7~44.8%) were significantly higher than those isolated from Geumho river basin (31.4~14.7%). About seventy percent (70.4%) of the strains isolated were resistant to one or more drugs tested. Thirty (39.5%) of 76 $TC^r$ E. coli isolates which were resistant to one or more drugs transferred all or a part of their resistance patterns to the recipient strain of E.coli J53 by conjugation. All of $TC^r$ E. coli isolates contained at least one or more of 5 tet genes examined. The most common genes found in these isolates were tetA (60.6%) and followed by tetB (7.9%) and tetC (1.3%). However, tetD and tetE were not found in any of the isolates tested. Twenty one (27.6%) of $TC^r$ E. coli isolates had two determinants, tetA/tetB (20 strains), tetA/tetC (1 strain). And two strains (2.6%) contained three determinants (tetA/tetB/tetC).