• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.47-55
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• 1984

To study the risk factors associated with maternal HBsAg carrier and the effects of maternal HBs antigenemia on the neonatal health, sera of 729 pergnant women admitted to the Keimyung University Hospital for delivery during the period of February 1-May 30. 1982 were tested for HBsAg by RPHA method and for anti-HBs by PHA method. Among them 43 women (5.9%) had HBsAg and 246 women (33.7%) had anti-HBs giving an infection rate of 39.6%. The interview data for 43 HBsAg positive mothers and randomly selected 210 HBsAg negative mothers showed a statistically significant association between acupuncture history and HBsAg positive rate (p<0.005) which suggest that acupuncture might have contributed significantly to the propagation of viral hepatitis in Korea. The living standard of HBsAg positive mothers was generally lower than that of HBsAg negative mothers which supports the hypothesis that environmental factors are associated with viral hepatitis B infection. None of the 43 neonates born to HBsAg positive mothers had HBsAg in their cord blood. Three months after birth, 35 out of 43 infants were retested and only one infant became HBsAg positive. At six months of age, 32 out of 35 infants were retested and none of them were HBsAg positive except the same infant who was positive at three months. Among 20 control infants of HBsAg negative mothers, all of them were HBsAg negative at three and six months follow-up. These findings are not consistent with the supposition that perinatal infection is a main route of viral hepatitis B transmission in south-east Asia including Korea. HBsAg positive mothers had significantly higher rate of premature delivery (27.9%) than HBsAg negative mothers (11.7%) (p<0.05). Also, the low birthweight incidence rate was higher among HBsAg positive mothers (23.3%) than negative mothers (14.1%) but this was not statistically significant (P=0.16). The premature rupture of membrane was more frequent among HBsAg positive mothers (25.5%) than negative mothers (11.1%) (p<0.05). There were no significant differences in the stillbirth rate and incidence of congenital anomalies between HBsAg positive and negative groups. It was not clarified in this study due to small sample size whether higher incidence of premature delivery and premature rupture of membranes among HBsAg positive mothers was due to HBs antigenemia per so or their lower living standard than HBsAg negative mothers.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.25-29
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• 1984

To assess the effect of noise on the blood pressure of workers, 70 weaving and 70 refining female workers in 15 to 24 years of ages were tested for the changes of blood pressure before and after exposure to the noise. The noise levels at work place were 99 dB (A) for weavers and 80 dB(A) for refiners. The mean age of refiners was 17,7 years and that of weavers was 18.6 years, and the difference in mean ages was statistically significant (p<0.05). The means of heights, weights and working durations were not significantly different between two groups. The mean systolic blood pressure of the weavers was 112.5mmHg before exposure to the noise and it was increased to 115.7mmHg after exposure to 99 dB(A) of noise for 30 minutes, and the mean diastolic blood pressure from 71.6mmHg to 74.1mmHg. These increments of blood pressure were statististically significant (p<0.05). The mean systolic blood pressure of the refiners was decreased from 108.9mmHg to 106.7mmHg after exposure to 80 dB(A) of noise for 30 minutes, and the mean diastolic blood pressure from 67.3mmHg to 67.1mmHg. These changes of blood pressure were not statistically significant. The mean systolic and diastolic blood pressure of the weavers before exposure to the noise were significantly higher than that of refiners (p<0.05). The difference of blood pressure between refiners and weavers was significantly associated with noises (p<0.05), and not ages and their interactions. The study results support the hypothesis that exposure to excessive noise increases the blood pressure of workers.

• Journal of Chest Surgery
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• v.29 no.2
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• pp.199-207
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• 1996

Ischemic myocardial damage is inevitable to cardiac surgery. Myocardial damage after initiation of reperfusion through the coronary arteries is one of the most important determinants of a successful surgery. Adenosine is a potent vasodilator, and is also known to induce rapid cardioplegic arrest by its property of antagonizing cardiac calcium channels and activating the potassium channel. Thus, we initiated this study with adenosine to improve postischemic recovery in the isolated rat heart. We tested the hypothesis that adenosine could be more effective than potassium in inducing rapid cardiac arrest and enhancing postischemlc hemodynamic recovery. Isolated rat hearts, connected to the Langendorff appratus, were perfused with Krebs-Henseleit buffer and all hearts were subjected to arrest for 60 minutes. Three groups of hearts were studied according to the composition of cardioplegic solutions : Group A (n=10), adenosine 10mmo1/L+potassium free modified St. Thomas cardioplegia : Group B (n=10), adenosine 400mo1/L+S1. Thomas cardioplegia:Group C(control, n=10), St. Thomas cardioplegia. Adenosine-treated groups (group A & B) resulted in more rapid cardiac arrest than control group (C) (p< 0.01). There was greater improvement in recovery of coronary blood flow at 20 and 30 minutes of reperfusion in group A and at 20 minutes in group B when compared with control group(p<0.01). Recovery of systolic blood pressure at 10 minutes after reperfusion in group A and B was significantly superior to that in group C (p<0.01). Recovery of dp/dt at 10 minute after reperfusion in group A was also significantly superior to group C (p<0.05). Group A and B showed better recovery rates than control group in aortic blood flow, cardiac output, and heart rate, but there were no statistical differences. CPK levels of coronary flow in group A were significantly low (p< 0.01). We concluded that adenosine-enriched cardioplegic solutions have better effects on rapid cardiac arrest and postischemic recovery when compared with potassium cardioplegia.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.295-301
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• 2004

Recently, the rapid increase and global spread of extended-spectrum $\beta-lactamase$ producing clinical isolates has become a serious problem. The incidence of extended-spectrum $\beta-lactamase$ producing clinical isolates of Escherichia coli in Korea and susceptibility to antimicrobial agents were investigated. Total 233 isolates of E. coli were obtained from urine from hospitalized patients in Guro hospital, Korea University in 2001. One hun­dred and eighty four isolates $(78.9\%)$ were resistant to ampicillin, 80 isolates $(34.3\%)$ were resistant to ceph­alothin, 93 isolates $(39.9\%)$ were resistant to gentamicin, and 64 isolates $(27.5\%)$ were resistant to norfloxacin. Among 233 isolates, 17 isolates $(7.3\%)$ were positive as determined by the double disk synergy test. When min­imal inhibitory concentrations were assayed with additional 6 antimicrobial agents, 13 isolates $(76.5\%)$ were multi-drug resistant to at least four different class antimicrobial agents. Extended-spectrum $\beta-lactamase$ were characterized with isoelectric focusing gel electrophoresis and DNA sequencing. They were TEM-1 in 5 iso­lates, TEM-15 in 1 isolate, TEM-20 in 1 isolate, TEM-52 in 4 isolates, TEM-1 and AmpC in 2 isolates, TEM-1 and OXA-30 in 1 isolate, TEM-1 and OXA-33 in 1 isolate, TEM-1, CTX-M-3, and AmpC in 1 isolate, but SHV was not detected. Antimicrobial resistance genes were transferred to animal isolate of E. coli (CCARM No. 1203) by the filter mating method. Extended spectrum $\beta-lactamase$ producers studied in the current study have low correlation to each other as determined by random amplified polymorphic DNA and pulsed field gel elec­trophoresis. This is a contradictory result from the general hypothesis that extended-spectrum $\beta-lactamase$ pro­ducers in one hospital is a result from a clonal spread.

• Journal of Animal Science and Technology
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• v.48 no.2
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• pp.255-268
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• 2006

Twenty four Hanwoo cull cows were assigned to 2 groups, control and melengerol acetate(MGA)+selenium supplement containing vitamin E(SeE), based on the parity(6.5±1.7 birth) and body weight (493.17±55.61kg), and the experiment was conducted to establish the reasonable fattening method of cull cows for 240 days. Average daily body gains during 240 days were 0.51kg and 0.63kg in control and MGA+SeE, respectively(P<0.10). DDMI/ADG of MGA+SeE group improved compared to control group(P<0.05). Therefore, supplementation of MGA+SeE in concentrates may accelerate both of the growth rate and feed efficiency in Hanwoo cull cows. MQI from MGA+SeE was more developed based on the larger rib-eye area and thinner backfat thickness in carcass than that from control. Marbling score for MGA+SeE tended to increase compared to control. Dietary Se supplementation significantly affected muscle Se concentration in longissimus dorsi meat of MGA+SeE group(P<0.05). Similar results to Se were obtained from α-Tocoperol concentration. During 7 days of simulated retail display, accumulations of thiobarbituric acid reactive substances(TBARS) concentration in beef was greater(P<0.05) in control than in supplemented cows. These results supported the hypothesis that supplementation of MGA+SeE improve the growth performance and carcass grade both by the growth stimulating effect of MGA+SeE and by preventing the oxidation of the longissimus dorsi muscle in Hanwoo cull cows.

• Applied Microscopy
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• v.39 no.1
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• pp.1-7
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• 2009

Experimental induction of polycystic ovary (PCO) resembling some aspects of human PCO syndrome was produced using the long-acting compound estradiol valerate (EV). Our previous study on the role of Korean red ginseng total saponins (GTS) in a steroid-induced PCO rat model demonstrated that electro-acupuncture modulates nerve growth factor (NGF) concentration in the ovaries. In fact, the involvement of a neurogenic component in the pathology of PCO-related ovarian dysfunction is preceded by an increase in sympathetic outflow to the ovaries. In the present study, we tested the hypothesis that therapeutic GTS administration modulates sympathetic nerve activity in rats with PCO. This was done by analyzing NGF protein and NGF mRNA expression involved in the pathophysiological process underlying steroid-induced PCO. EV injection resulted in significantly higher ovarian NGF mRNA expression in PCO rats compared to control rats, and PCO ovaries were counteracted by GTS administration with significantly lower expression of NGF mRNA compared to EV treated ovaries. However, NGF protein was unaffected in both EV and GTS treated ovaries compared to control rats. These results indicate that EV modulates the neurotrophic state of the ovaries, which may be a component of the pathological process by which EV induces cyst formation and anovulation in rodents.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.137-147
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• 2017

The identity of toxin producers remains only hypothesis unless there were identified by strain isolation and analytical confirmation of both the cyanotoxin production and the genetic identity of the monoculture. The purposes of this study were to identify a morphologic and phylogenetic classification in Aphanizomenon flos-aquae strains isolated from the Nakdong River and to investigate the potential ability of the strains to produce toxins such as saxitoxin and cylindrospermopsin using target genes. The 16S rRNA and sxtA, sxtI, cyrA, cyrJ genes were analyzed on two strains (DGUC001, DGUC003) isolated from the Nakdong River. Morphological features of the strains were observed a shape of aggregated trichomes in parallel fascicles which can reach up to macroscopic size and a hyaline terminal cell without aerotope. In addition, the 16S rRNA phylogenetic analyses showed that the strains were identified as the same species with high genetic similarity of 98.4% and grouped within a monospecific andsupported cluster I of Aphanizomenon flos-aquae selected from GenBank of the NCBI. The cyrA and cyrJ genes encoding for the cylindrospermopsin-biosynthesis were not detected in the present study. The sxtA gene was in detected both the two strains, whereas the sxtI gene which had been suggested as a suitable molecular marker to detect saxitoxin-producing cyanobacteria was not found both the strains. Thus, the two strains isolated from Nakdong River were identified as the same species of Aphanizomenon flos-aquae Ralfs ex Bornet et Flahault 1888, the two strains were confirmed as potential non-producing strains of the saxitoxin and cylindrospermopsin.

• Journal of the Korean Society for Library and Information Science
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• v.18
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• pp.277-325
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• 1990

The purpose of this study was to determine the effectiveness of instructors' utilization of the reserve collection in the university library. To accomplish this, an experiment-and-questionnaire study was done by selecting an experimental group for whom the teaching method utilizing the reserve collection was used and a control group for whom the method was not used. An experimental group and a control group studied were as follows: (1) Students take the 'Comparative Politics' course in the Department of Political Science. (2) Students take the 'History of 'English Literature' course III the Department of English Language and Literature. The data to test the hypothesis were analyzed by SPSS/PC+ routine. The results are as follows: (1) There were significant differences between the experimental group and the control group in academic achievement(T(228)=6.69, P<.01). To investigate the difference in effect by major, the one-way analysis of variance was employed. According to the results, there were significant differences between the experimental group and the control group In the Department of Political Science and the Department of English Language & Literature. Therefore, students for whom the teaching method utilizing the reserve collection was used have higher academic achievement than those for whom the method was not used. (2) As for the degree of utilizing the library and its materials, there were significant differences between the experimental group and the control group(T(228)=8.87, P<.01). As for the results of the one-way analysis of variance to investigate the difference in effect by major, there were significant differences between the experimental group and the control group in both departments. As for the degree of utilizing library catalogues and bibliographical tools, there were significant differences between the experimental group and the control group(T (228)=8.55, P<.01). As stated earlier, the one-way analysis of variance to investigate the difference in effect by major has shown that there were significant differences between the experimental group and the control group in both departments. As for the degree of sincerity in doing homework and writing papers, there were significant differences between the experimental group and the control group(T(176)=8. 03, P<.01). To investigate the difference in effect by major, the one-way analysis of variance was again employed. According to the results, there were again significant differences between the experimental group and the control group in both departments. So, the students for whom the teaching method utilizing the reserve collection was employed used library catalogues and bibliographical tools much more than those for whom the method was not employed, and were more sincere in doing homework and writing papers. (3) There were also significant differences between the experimental group and the control group in degree of satisfaction in taking the course (T (228) = 6.61, P<.01). The results of the one-way analysis of variance to investigate the difference in effect by major was that there were significant differences between the experimental group and the control group in both departments. Therefore, the degree of satisfaction of students who were taught by the teaching method utilizing the reserve collection is higher than that of those who were not taught by the method. On the other hand, the responses of the experimental groups of two departments as to the degree of satisfaction with their teaching method was investigated. The result shows that students who took the 'Comparative Politics' course in a small class which employed the seminar method were higher in degree of satisfaction with the teaching method than students who took the 'History of English Literature' course III a large class which employed a lecture-oriented teaching method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.2
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• pp.141-149
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• 2004

The aim of this study was to test the validity of the hypothesis that the karyotypes of four species of Lepilemuridae were formed spontaneously from their ancestral hybrid karyotype. Hypothetical ancestral haploid Karyotype of Lepilemuridae is composed of 18 autosomes and X chromosomes. Lepilemur mustelinus karyotype has four tandem fused chromosomes and one Robertsonian translocated chromosome pairs. Lepilemur septentrionalis septentrionalis karyotype has only two pairs of translocated chromosomes. We reconstruct and suggest ancestral karyotype of LMU(ancLMU) and LSS(ancLSS), from which all four studied species were derived. Hybrids of ancLMU and ancLSS were formed and produce differently fused equilibrated gametes via circular form arrangement during gametogenesis. Five unit of trivalent homologous chromosome pairs were engaged in a circular form to give new gamete corresponding to the karyotype of L. dorsalis, orientation of one unit of trivalent was inversed in the circle to gave new gamete corresponding to the karyotype of L. leucopus. Seven homologous chromosome pairs were engaged in circular form to give haploid karyotype of Lepilemur ruficaudatus. Only one homologous chromosome pair is dissociated and the other chromosome pairs rearranged in the circle to form haploid karyotype of Lepilemur edwardsi. The new gametes could be produced from these circular forms. When the new gamete fertilized with the same type of gamete, The new homozygote is produced as existing L. dorsalis, L. leucopus, L. edwardsi and L. ruficaudatus. These results support the theory that new species could be formed in hybrid population through activated chromosome fusion, chromosome rearrangement in circular from at zygotene stage and production of equilibrated gametes to form homozygote new species.

• Restorative Dentistry and Endodontics
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• v.34 no.1
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• pp.42-50
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• 2009

Deterioration of long-term dentin adhesion durability is thought to occur by hydrolytic degradation within hydrophilic domains of the adhesive and hybrid layers. This study investigated the hypothesis that priming the collagen network with an organic solvent displace water without collapse and thereby obtain good bond strength with an adhesive made of hydrophobic monomers and organic solvents. Three experimental adhesives were prepared by dissolving two hydrophobic monomers, bisphenol-A-glycidylmethacrylate (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA), into acetone, ethanol or methanol. After an etching and rinsing procedure, the adhesives were applied onto either wet dentin surfaces (wet bonding) or dentin surfaces primed with the same solvent (solvent-primed bonding). Microtensile bond strength (MTBS) was measured at 48 hrs, 1 month and after 10,000 times of thermocycles. The bonded interfaces were evaluated using a scanning electron microscope (SEM). Regardless of bonding protocols, well-developed hybrid layers were observed at the bonded interface in most specimens. The highest mean MTBS was observed in the adhesive containing ethanol at 48 hrs. With solvent-primed bonding, increased MTBS tendencies were seen with thermo cycling in the adhesives containing ethanol or methanol. However, in the case of wet bonding, no increase in MTBS was observed with aging.