The effect of strain aging on the tensile properties of API X70 linepipe steel was investigated in this study. The API X70 linepipe steel was fabricated by controlled rolling and accelerated cooling processes, and the microstructure was analyzed using optical and scanning electron microscopes and electron backscatter diffraction. Strain aging tests consisting of 1% pre-strain and thermal aging at 200 oC and 250 oC were conducted to simulate U-forming, O-forming, Expansion(UOE) pipe forming and anti-corrosion coating processes. The API X70 linepipe steel was composed of polygonal ferrite, acicular ferrite, granular bainite, and bainitic ferrite whose volume fraction was dependent on the chemical composition and process conditions. As the thermal aging temperature increased, the steel specimens showed more clearly discontinuous type yielding behavior in the tensile stress-strain curve due to the formation of a Cottrell atmosphere. After pre-strain and thermal aging, the yield and tensile strengths increased and the yield-to-tensile strength ratio decreased because yielding and aging behaviors significantly affected work hardening. On the other hand, uniform and total elongations decreased after pre-strain and thermal aging since dislocation gliding was restricted by increased dislocation density after a 1% pre-strain.

A entomopathogenic ascomycetous fungus, Cordyceps militaris is distributed world wide and cultivated as a medicinal mushroom having many valuable biological and pharmaceutical activities. In the breeding of new C. militaris mushroom, single ascospores were isolated and tested their characteristics such as mycelial growth, mycelial density, fruiting body formation ability, the production of perithecia. Also two opposite mating types were assayed using two sets of primers specific for C. militaris, which were amplified a 191-bp fragment for MAT1-1 and 233-bp fragment for MAT1-1. F1 hybrids resulted in well-developed perithecial fruiting bodies and their crossings were confirmed by the PCR assays. New hybrids were produced showing high quality fruiting bodies in artificial media. Mycelial growth of new strain 'Dowonhongcho 2’ was better on SDAY and at 15-25°C when it was compared with that of 'Yedang 3'. The stromata of new strain were club-shaped and bright orange-red color. Its length was 7.1 cm and the cordycepin content was 0.33% on average. In comparison with 'Yedang 3', the new strain had a yield that was 7% higher and it produced fruiting bodies which were firmer. Days of fruiting body were similar with 50 days from inoculation. This cultivar may serve as a valuable one for artificial cultivation and industrial-scale production of C. militaris.

For heaths and vitality Cordyceps sinensis has been widely used as an important medicinal mushroom. C. militaris is popular for its substitute and can be cultivated artificially. Its new strains have been improved by crossing single spore strains. A bipolar heterothallic fungus, C. militaris has two strains of compatible mating types and they can be differentiated by crossing, fruiting body formation ability and the production of perithecia. Each isolate was determined to be monokaryotic or dikaryotic on the basis of perithecial formation by fruiting tests. This process was also carried out by molecular markers for the detection of two opposite mating types or F1 hybrids using two sets of primers specific for C. militaris amplifying a 191-bp fragment for MAT1-2 and 233-bp fragment for MAT1-1. Therefore the crossing of two compatible mating types resulted in well-developed perithecial fruiting bodies and their crossings were confirmed by the PCR assays for the rapid and specific detection of both MAT1-1 and MAT1-2. This results showed that molecular markers provide an efficient alternative for identification of hybridal status or mating types in the breeding program for artificial cultivation and industrial-scale production of C. militaris.

Diets rich in flavonoid-containing foods are sometimes associated with cancer, neurodegenerative and cardiovascular disease prevention. β-glucan, one of the most important bioactive compounds in medicinal mushrooms, is used to boost the immune system, diabetes and cancer. In this study, we aimed to determine the content of two flavonoid compounds (naringenin and naringin) and β-glucan in Flammulina velutipes and Flammulina velutipe-gold strain. The naringenin, naringin, and β-glucan components from the Flammulina velutipes and Flammulina velutipe-gold strain were measured by the HPLC analysis. As a result, the contents of naringenin, naringin, and β-glucan were found to be much higher in Flammulina velutipe-gold strain than Flammulina velutipe. From the above results, we may suggest that Flammulina velutipe-gold strain might have useful as a material for functional food and pharmaceutics fir the pathological process of various human diseases.

In the seismic design of building structural members, due to the complexity of the placement of PC steels in prestressed concrete members, it is necessary to review and define the definition of member damage in comparison with reinforced concrete members.In this study, the results of past experiments compared with the calculation results by ‘section Analysis Method’, with the aim of reviewing the precision of calculation results when member damage evaluation is performed using the section analysis method. Furthermore, it is also compared with the calculation results by the ‘split Element Method’.In addition, parametric studies were carried out, and the influence of the difference between the amount of PC steels and reinforced bar on the residual strain was examined.

We developed single nucleotide polymorphism (SNP) markers and are establishing diagnostic systems to distinguish disease resistance- and susceptible-strains of honey bees using the SNPs. For development of SNP markers, whole genome was sequenced each from 20 individuals of “disease resistance-strain” and “susceptible-strain” of Apis mellifera ligustica using the Illumina HiSeq 2000 sequencer. Approximately, 344 and 294 million sequence reads were mapped to the honeybee reference assembly (Amel_4.5) for each strain, respectively. Among the total 2,246,428 SNPs yielded, 33 were found to be fixed between the two strains with all homozygosity. Sixteen of them were casually amplified and sequenced from randomly selected each 10 individual of honey bees from each strain and presented strain specific SNPs. These ten SNPs were used to diagnose the two strains either by original size difference, caused by indel-accompanying SNP, typical PCR-RFLP, or AS PCR.

Ryanodine receptors (RyRs) regulate the contractions of insect muscles by altering intracellular Ca2+ concentration and are the targets of chlorantraniliprole. Here we established two resistant strains of Drosophila melanogaster, which were treated with low or high concentrations of chlorantraniliprole, and their resistance levels were determined on the basis of contact and ingestion toxicities. Compared with the wild type, the two resistant strains did not show any significant differences in contact toxicity. However, they showed significantly increased resistance ratios in ingestion toxicity than that by the wild type. The resistant strains had altered expression levels of RyRs and more enhanced Acetylcholinesterase and Glutathione-S-transferase activities than that by the non-selected strain. These results suggested that the resistance development of chlorantraniliprole in the two strains might be mediated by the activation of detoxification pathways in D. melanogaster.

PURPOSES: This study is primarily focused on evaluating the effects of the non-linear stress-strain behavior of RAP concrete on structural response characteristics as is applicable to concrete pavement. METHODS : A 3D FE model was developed by incorporating the actual stress-strain behavior of RAP concrete obtained via flexural strength testing as a material property model to evaluate the effects of the non-linear stress-strain behavior to failure on the maximum stresses in the concrete slab and potential performance prediction results. In addition, a typical linear elastic model was employed to analyze the structural responses for comparison purposes. The analytical results from the FE model incorporating the actual stress-strain behavior of RAP concrete were compared to the corresponding results from the linear elastic FE model. RESULTS : The results indicate that the linear elastic model tends to yield higher predicted maximum stresses in the concrete as compared to those obtained via the actual stress-strain model. Consequently, these higher predicted stresses lead to a difference in potential performance of the concrete pavement containing RAP. CONCLUSIONS : Analysis of the concrete pavement containing RAP demonstrated that an appropriate analytical model using the actual stress-strain characteristics should be employed to calculate the structural responses of RAP concrete pavement instead of simply assuming the concrete to be a linear elastic material.

This paper is concerned with a test method that can be used to investigate the parameters of the Johnson-Cook constitutive model. These parameters are essential for accurately analyzing material behavior under impact loading conditions in numerical simulation. Ti-6Al-4V alloy (HCP crytal structure) was used as a specimen for the experiments. In the 10−3-103/ s strain rate range, three types of experimental methods (convention, compression and tension) were employed to compare the differences using MTS-810, SHPB and SHTB. Finite element analysis results when applying these parameters were displayed along with the experiment results.

Due to a lack of the hoop action of lateral reinforcements the effective confining force in rectangular sections reduces compared to circular ones. Therefore, the stress-strain model obtained from the experimental data with circular sections overestimates the lateral confinement effect in rectangular sections, which evaluates seismic safety margin of overall structural system excessively. In this study experiments with laterally-confined square sections have been performed and the characteristic values composing stress-strain model have been analyzed. With introduction of section coefficients, in addition, the new unified stress-strain model applicable to square sections as well as circular ones has been proposed.

In order to avoid collapse of bridges in earthquakes bridge piers are generally designed to attain sufficient ductility. This full-ductility design method has merits for securing the seismic safety readily against strong earthquakes but, it has weakness of high cost design because of excessive safety margin. Recently, in many countries with high seismic technologies, the seismic design concept tends to shift from the collapse prevention design to the performance-based one which requires different performance (damage) levels according to the structural importance. In order to establish this performance-based design method the displacement ductility of confined concrete members should be evaluated quantitatively. And the stress-strain model of confined concrete is indispensible in evaluating displacement ductility. In this study, 6 test groups with different lateral reinforcement ratios were prepared. 10 same specimens with circular section for each group were tested to obtain more reliable test results. The characteristic values necessary for composing the stress-strain model were obtained from experiments. Based on these characteristic values the new stress-strain model modifying the Hoshikuma's one has been proposed.

One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as 134Cs, 135Cs, and 137Cs. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on Cs+ tolerant bacteria. In this study, we report the isolation and identification of Cs+ tolerant bacteria in environmental soil and sediment. The resistant Cs+ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries (NCBI’s BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh- 2 is resistant to 30% more Cs+ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to Cs+. In addition, we investigated the adsorption of 0.2 mg L-1 Cs+ using B. anthracis Roh-1. The maximum Cs+ biosorption capacity of B. anthracis Roh-1 was 2.01 mg g-1 at pH 10. Thus, we show that Cs+ tolerant bacterial isolates could be used for bioremediation of contaminated environments.

Cordyceps species are important mushrooms traditionally used for heaths and vitality. C. sinensis has been widely used as a medicinal mushroom and C. militaris is popular for its substitute. C. militaris can be cultivated artificially and new strains has been improved by crossing single spore strains. As a bipolar heterothallic fungus C. militaris has two strains of compatible mating types and they can be differentiated by crossing, fruiting body formation ability and the production of perithecia. However this process is very laborious and time consuming to carry out. In this study, molecular markers were designed and used for the detection of two opposite mating types. Two mating types were assayed using two sets of primers specific for C. militaris, which were amplified a 191-bp fragment for MAT1-2 and 233-bp fragment for MAT1-1. After crossing of two compatible mating types F1 hybrids resulted in well-developed perithecial fruiting bodies and their crossings were confirmed by the multiplex PCR assays for the rapid and specific detection of both MAT1-1 and MAT1-2. This results may serve as a efficient process in the breeding program for artificial cultivation and industrial-scale production of C. militaris.

The present study deals with the effects of micro-alloying elements such as Ni, V, and Ti on the recrystallization behavior of carbon steels at different strain rates. Eight steel specimens were fabricated by varying the chemical composition and reheating temperature; then, a high-temperature compressive deformation test was conducted in order to investigate the relationship of the microstructure and the recrystallization behavior. The specimens containing micro-alloying elements had smaller prior austenite grain sizes than those of the other specimens, presumably due to the pinning effect of the formation of carbonitrides and AlN precipitates at the austenite grain boundaries. The high-temperature compressive deformation test results indicate that dynamic recrystallization behavior was suppressed in the specimens with micro-alloying elements, particularly at increased strain rate, because of the pinning effect of precipitates, grain boundary dragging and lattice misfit effects of solute atoms, although the strength increased with increasing strain rate.

In the present study, the tensile properties and dynamic strain aging of an Fe-24.5Mn-4Cr-0.45C alloy were investigated in terms of strain rate. During tensile testing at room temperature, all the stress-strain curves exhibited serrated plastic flows related to dynamic strain aging, regardless of the strain rate. Serration appeared right after yield stress at lower strain rates, while it was hardly observed at high strain rates. On the other hand, strain-rate sensitivity, indicating a general relationship between flow stress and strain rate at constant strain and temperature, changed from positive to negative as the strain increased. The negative strain-rate sensitivity can be explained by the Portevin Le Chatelier effect, which is associated with dynamic strain aging and is dependent on the strain rate because it is very likely that the dynamic strain aging phenomenon in high-manganese steels is involved in the interaction between moving dislocations and point-defect complexes.

Dextran is a generic term for a bacterial exopolysaccharide synthesized from sucrose and composed of chains of D-glucose units connected by α-1,6-linkages by using dextransucrases. Dextran could be used as vicosifying, stabilizing, emulsifying, gelling, bulking, dietary fiber, prebiotics, and water holding agents. We isolated new strain capable of producing dextran from Korean traditional kimchi and identified as Leuconostoc sp. strain JYY4. Batch fermentation was conducted in bioreactor with a working volume of 3 L. The media was MMY and 15% (w/v) sucrose. Mineral medium consisted of 3.0 g KH2PO4, 0.01 g FeSO4, H2O, 0.01 g MnSO4, 4H2O, 0.2 g MgSO4 7H2O, 0.01 g NaCl, 0.05 g CaCl2 per 1 liter deionized water. The pH of media was initially adjusted to 6.0. The inoculation rate was 1.0% (v/v) of the working volume. Temperature was maintained at 28oC. The agitation rate was 100 rpm. The production pattern of dextran was associated with the cell growth. After 24 hr dextran reached its highest concentration of 59.4 g/L. The sucrose was consumed completely after 40 hr. Growth reached stationery phase when sucrose became limiting, regardless of the presence of fructose or mannitol. When the specific growth rate was 0.54 hr-1, utilization averaged 5.8 g/L-hr. The yield and productivity of dextran were 80% and 2.0 g/L-hr, respectively. Dextrans produced by were separated to two different size by an alcohol fraction method. The size of high molecular weight dextran (45% alcohol, v/v), less soluble dextran, was between MW 500,000 and 2,000,000. Soluble dextran (55% alcohol, v/v) was between 70,000 and 150,000. The molecular weight average of total dextran (70% alcohol, v/v) was between 150,000 to 500,000. The enzymatic hydrolyzates of total dextran of ATCC 13146 showed branched dextrans by Penicillium dextranase contained of glucose, isomaltose, isomaltotriose, and isomaltooligosaccharides greater than DP4 (degree of polymerization) that had branch points. Compounds greater than DP4 were branched isomaltooligosaacharides. Hydrolysates by the Lipomyces dextranase produced the same composition of oligosaccharides as those by Penicillin dextranase.

KO mice provide an excellent tool to determine roles of specific genes in biomedical filed. Traditionally, knockout mice were generated by homologous recombination in embryonic stem cells. Recently, engineered nucleases, such as zinc finger nuclease, transcription activator-like effector nuclease and clustered regularly interspaced short palindromic repeats (CRISPR), were used to produce knockout mice. This new technology is useful because of high efficiency and ability to generate biallelic mutation in founder mice. Until now, most of knockout mice produced using engineered nucleases were C57BL/6 strain. In the present study we used CRISPR-Cas9 system to generate knockout mice in FVB strain. We designed and synthesized single guide RNA (sgRNA) of CRISPR system for targeting gene, Abtb2. Mouse zygote were obtained from superovulated FVB female mice at 8-10 weeks of age. The sgRNA was injected into pronuclear of the mouse zygote with recombinant Cas9 protein. The microinjected zygotes were cultured for an additional day and only cleaved embryos were selected. The selected embryos were surgically transferred to oviduct of surrogate mother and offsprings were obtained. Genomic DNA were isolated from the offsprings and the target sequence was amplified using PCR. In T7E1 assay, 46.7% among the offsprings were founded as mutants. The PCR products were purified and sequences were analyzed. Most of the mutations were founded as deletion of few sequences at the target site, however, not identical among the each offspring. In conclusion, we found that CRISPR system is very efficient to generate knockout mice in FVB strain.

Bi0.5Na0.5TiO3 (BNT) based ceramics are considered potential lead-free alternatives for Pb(Zr,Ti)O3(PZT) based ceramics in various applications such as sensors, actuators and transducers. However, BNT-based ceramics have lower electromechanical performance as compared with PZT based ceramics. Therefore, in this work, lead-free bulk 0.99[(Bi0.5Na0.5)0.935Ba0.065](1-x)LaxTiO3-0.01SrZO3 (BNBTLax-SZ, with x = 0, 0.01, 0.02) ceramics were synthesized by a conventional solid state reaction The crystal structure, dielectric response, degree of diffuseness and electric-field-induced strain properties were investigated as a function of different La concentrations. All samples were crystallized into a single phase perovskite structure. The temperature dependent dielectric response of La-modified BNBT-SZ ceramics showed lower dielectric response and improved field-induced strain response. The field induced strain increased from 0.17% for pure BNBT-SZ to 0.38 % for 1 mol.% La-modified BNBT-SZ ceramics at an applied electric field of 6 kV/mm. These results show that Lamodified BNBT-SZ ceramic system is expected to be a new candidate material for lead-free electronic devices.