• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.1002-1012
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• 2001

The work reported here is an extensive study of tendon response to multiple cyclic tests including 3% constant peak strain level test (A-type test), 3% constant peak strain level test with two rest periods (B-type test), and 3∼4% different peak strain level test (C-type test). A sufficient number of specimens were tested at each type of the test to statistically evaluate many changes in response during testing and differences in response between each type of the test. In cyclic tests, there were decreses (relaxations) in the peak stresses and hysteresis, increases in the slack strains, and during lower peak strain level (3%) cyclic block after higher peak strain level (4%) cyclic block in the C-type tests. Considering the results of this study and those of the other study of multiple cyclic tests with rest periods by Hubbard and Chun, 1985, recovery phenomena during the rest periods occurred predominantly at the beginning of the rest periods. Consistently in both studies, the effects of rest periods were small and transient compared to the effects of the cyclic extensions. The recovery with cycles at lower peak strain level (3%) after higher peak strain level (4%) in the C-type test has not been previously documented. This recovery seems to be a natural phenomena in tissue behavior so that collagenous structures recover during periods of decreased demand.

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.83-89
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• 1990

Two strains of actinomycetes producing extracellular adenosine deaminase, strain J-845S and strain J-326TK, were isolated from soil. Strain J-845S was gram-positive and non-acid-fast. This strain formed whitish, rod-shaped, smooth and non-motile spores on the aerial mycelium, and the spore chain was spiral. The hyphae of the mycelium branched abundantly. Cell wall chemotypes of the strain were of type I containing LL-diaminopimelic acids, and of phospholipid type II, and then strain J-845S was designated as Streptomyces sp.. Strain J-326TK was gram-positive and non-acid-fast. The hyphae of primary and aerial mycelium fragmented into irregular rod of coccus-like elements. The aerial mycelium either did not branch or sparsely branched. Cell wall composition was of type I and phospholipid type I. Thus, strain J-326TK was identified as Nocardioides sp.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.4
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• pp.75-82
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• 2014

A pin-type load-cell which uses shear-type strain gauges was developed to measure the tension of a wire in a winch. A finite element analysis was performed to determine the locations of the strain gauges. All of the shear-type strain gauges were attached onto parts that undergo regularly shear stress distributions. A Wheatstone bridge circuit was used to connect each of the gauges and to measure the strains. Linearity within the 5% error range was noted when testing the pin-type load-cell.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.206-216
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• 2015

To clarify the role of surface protective antigen A (SpaA) in the pathogenesis of Erysipelothrix rhusiopathiae C43065 (serotype 2), the spaA deletion mutant of E. rhusiopathiae ${\Delta}spaA$ was constructed by homologous recombination. The virulence of the ${\Delta}spaA$ mutant decreased more than 76-fold compared with that of the wild-type strain C43065 in mice. The mutant strain was sensitive to the bactericidal action of swine serum, whereas the wild-type strain was resistant. The adhesion of wild-type strain to MEF cells was inhibited significantly by treatment with rabbit antiserum against recombinant SpaA (rSpaA) as compared with the treatment with normal rabbit serum, but the mutant strain was not affected. The mutant strain was readily taken up by mouse peritoneal macrophages in the normal rabbit serum, whereas the wild-type strain was resistant. Whereas the rabbit antiserum against rSpaA promoted the phagocytosis of wild-type strain by macrophages, the mutant strain was not affected. In addition, mice vaccinated with the formalin-killed mutant strain were provided 40% protection against challenge by the homologous virulent strain as compared with those with wild-type strain, NaOH-extracted antigen, or rSpaA, which provided more than 80% protection against the same infection. These suggested that SpaA has an important role in the pathogenesis of E. rhusiopathiae infection and could be a target for vaccination against swine erysipelas.

• Journal of Aquaculture
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• v.9 no.3
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• pp.187-194
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• 1996

Sixteen strains of marine rotifer, Braohionus plicatilis were isolated from salt pond, estuary and lagoon. Among 16 strains, 2 strains were large (L)-type and the others were small (S) or ultra small (US)-type. Four strains of fresh water rotifer, B. calyciflorus were isolated from commercial fish ponds. The size of lorica and resting egg were measured. In B. plicatilis, the range of lorica length from S-type and S-type were $244.3{\~}255.3\;{\mu}m$ and $131.0{\~}165.8\;{\mu}m$, respectively. The major axis of resting egg in the marine rotifer were $93.7\~116.4\;{\mu}m$ for S-type and $142.4{\~}145.5\;{mu}m$ for L-type, respectively. In freshwater rotifer, B. calyciflorus, the size range of lorica and major axis of resting egg were $211.8\~229.9\;{\mu}m$ and $126.8\~140.2\;{mu}m$, respectively. The size of freshwater rotifer was larger than that of S-type marine rotifer, but smaller than that of L-type one. Growth and formation of resting egg of B. plicatilis were different among the strains. The maximum density of S-type and L-type rotifer was 753.3 inds./ml for H-S strain and 220 inds./ml for O-L strain, respectively. The largest production of resting egg of S-type and L-type rotifer were 86.7 inds./ml for YY-S strain and 45.8 inds./ml for O-L strain, respectively.

• Korean Journal of Veterinary Research
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• v.51 no.3
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• pp.193-201
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• 2011

An attenuated vaccine strain AVR1/08 of Korean respiratory type of infectious bronchitis virus (IBV) was developed by 89th passages of IBV D85/06 strain in chicken eggs. The AVR1/08 strain had higher virus titer at least 20 times ($10^{1.3}$) than the parent virus D85/06 by egg inoculation method. The AVR1/08 strain had a single point mutation (S to Y) at position 56 of spike protein of IBV compared to parent virus IBV D85/06 strain. The mutation was observed consistently at viruses after 47th passage in chicken eggs. The AVR1/08 strain showed no virulence even after 6 passages in chickens and all chickens inoculated induced anti-IBV antibody 14 days after vaccination. The AVR1/08 strain had broad protective efficacy against QX type Korean nephropathogenic virus (Q43/06 strain), KM91 type Korean nephropathogenic virus (KM91 strain) and Korean respiratory virus (D85/06 strain). In contrast, Massachusetts (Mass) type attenuated vaccine strain H120 showed protection of 37.5 to 50% against these three viruses. Our results indicate that the AVR1/08 strain has potential as an attenuated vaccine effective in controlling IBVs circulating in Korea.

• Journal of Microbiology
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• v.44 no.1
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• pp.113-120
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• 2006

Candida tropicalis was treated with ultraviolet (UV) rays, and the mutants obtained were screened for xylitol production. One of the mutants, the UV1 produced 0.81g of xylitol per gram of xylose. This was further mutated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and the mutants obtained were screened for xylitol production. One of the mutants (CT-OMV5) produced 0.85g/g of xylitol from xylose. Xylitol production improved to 0.87 g/g of xylose with this strain when the production medium was supplemented with urea. The CT-OMV5 mutant strain differs by 12 tests when compared to the wild-type Candida tropicalis strain. The XR activity was higher in mutant CT-OMV5. The distinct difference between the mutant and wild-type strain is the presence of numerous chlamvdospores in the mutant. In this investigation, we have demonstrated that mutagenesis was successful in generating a superior xylitol-producing strain, CT-OMV5, and uncovered distinctive biochemical and physiological characteristics of the wild-type and mutant strain, CT-OMV5.

• Journal of Plant Biology
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• v.1 no.1
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• pp.1-6
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• 1958

1. Study was made to investigate effects of desoxyribonucleates on copper-resistance in yeast. 2. It is found that the resistant strain there exists the phenomic lag. 3. In the occurrence of the resistant strain there exists the phenomic lag. 4. Desoxyribonucleate isolated from copper resistant culture is capable of inducing the resistant strain, which is the same type as donor of the resistant type. It accelerated the rate of variation to the resistant, but it is of no effect on the resistant strain. 5. Desoxyribonucleate derived from non-resistant type inhibits growth of the resistant strain and delays the initial phase of growth. However, it is of no effect on the sensitive strain. It is concluded that desoxyribonucleate derived from resistant culture is capable of inducing the resistance, however, nonresistant type desoxyribonucleate is of no effect on inducing the resistance.

• The Korean Journal of Mycology
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• v.34 no.2
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• pp.88-91
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• 2006

Attempts were made to investigate the conditions of mycelia of one low-temperature type strain and one high-temperature type strain of shiitake showing poor fruit-body formation in bed-log, and to survey harmful microorganisms formed on the log surface in Gapyung County, Korea. When tested the growing ability of mycelia, the low-temperature type strain showed ca. 1.1% decrease compared with preserved original strain. And, the high-temperature type one showed ca. 8.0% decrease. The growth of isolated mycelia was tested in sawdust medium. The high-temperature type strain showed ca. 10.8% decrease compared with original strain, and the low-temperature type one showed ca. 25.1% decrease. Weight reduction rate was investigated. The high-temperature strain showed ca. 20.1% decrease and the low-temperature one ca. 19.0%. When compared with non-treatment, original high-temperature type strain showed 107.0% decrease, the isolated high-temperature type strain 49.5%, original low-temperature type one 85.4%, isolated low-temperature type one 50.0%. As the results of confrontation culture, the high-temperature type strain and the low-temperature type one were same as the original ones, respectively. And, in the bed-logs, Hypoxylon truncatum, Coriolus versicolor, Inonotus xeranticus, Daedaleopsis tricolor, Graphostroma platystoma, two species of Myxomycetes, Trichoderma sp. Hypoxylon fragiforme, H. howeianum, and Nitschkia confertula were observed as harmful microorganisms, and the bed-logs were not in good condition.

• Bulletin of the Society of Naval Architects of Korea
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• v.7 no.2
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• pp.27-40
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• 1970

The distribution of stress and strain in elastic stages is investigated by the experiments of two dimensional photoelastic coating and Moire fringe method. Center block type and cover plate type of fillet welds are used as specimens in the test. The results are as follows. 1) Center block type gets less uniform stress distribution than cover plate type. And its stress concentration factor, especially at root, is larger than that at toe. 2) When main plate and cover plate closely contact and it cause friction, stress concentration decreases more than that in case of slit. That is because stress can be transmitted on the contact surface. 3) When slit is made, the outside of fillet gets more stress than the inside of it. 4) While the plastic strain distribution of center block type reaches the maximum at root and differs very slightly from that under lower loading, the plastic strain distribution of cover plate type is inclined to get the maximum at the outside of fillet rather than at root. 5) When the plastic strain value of cover plate type is compared with that of center block type at toe and root, the relations between the former and the latter shows root<toe and root>toe. 6) Because stress distribution becomes changed according to loading, fracture angle cannot be estimated by the peaks of elastic stress distribution. 7) The strain distribution just before fracture can be found by Moire fringe method.