• ALGAE
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• 제28권2호
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• pp.185-192
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• 2013

A new cold-adapted Arctic strain of Haematococcus pluvialis from Blomstrandhalv${\o}$ya Island (Svalbard) is described. This strain is predominantly always in non-motile palmelloid stage. Transmission electron microscopy showed the presence of very thick cell wall and abundant lipid vesicles in the palmelloids, including red and green cells. The external morphology of the non-motile palmelloid and motile bi-flagellated cells of our strain is similar to H. pluvialis; however it differs from H. pluvialis in physiology. Our strain is adapted to live and produce astaxanthin in the low temperature ($4-10^{\circ}C$), whilst the usual growth temperature for H. pluvialis is between $20-27^{\circ}C$. Phylogenetic analysis based on 18S rRNA gene data showed that our strain nested within the Haematococcus group, forming a sister relationship to H. lacustris and H. pluvialis, which are considered synonymous. Therefore, we identified our Arctic strain as H. pluvialis.

• 생약학회지
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• 제15권1호
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• pp.15-23
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• 1984

To find antimicrobial strains of the soil microorganisms in Korea, they were isolated from the soil samples of different locations and screened for antibiotic activity against several standard microbes. An isolate among them had an antibacterial activity against gram-positive bacteria. The examination of its morphological and biochemical characteristics according to the International Streptomyces Project methods showed that it belongs to the genus Streptomyces. The strain was named DMC-72. The strain appears to be a new strain when it was compared with the species within the genus which have been so far reported. The antibiotic metabolite of the strain was produced in submerged culture method. It was found to be a quinone compound and was named soulomycin. This strain was also found to produce an ${\alpha}-amylase$ inhibitor in the submerged culture.

• The Journal of Korean Physical Therapy
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• 제31권4호
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• pp.254-259
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• 2019

Purpose: This study examined the interactions between the job strain and social support in the workplace on the development of workrelated neck pain in office workers. Methods: The participants included 62 office workers without neck pain over the last twelve months. A battery of measures evaluating the potential workplace risk factors in office settings were conducted at the baseline, and at the 12 month incidence of work-related neck pain was reported via monthly questionnaires. Survival analysis evaluated the interaction effect between job strain and social support on the development of work-related neck pain. Results: The incidence of work-related neck pain was 1.91 (95% CI: 1.06 - 3.45) per 100 person months. The interaction effect between job strain and social support found that job strain may increase the risk of developing new work-related neck pain when lower social support existed in the workplace. On the other hand, the adverse effects of job strain on the development of neck pain were not significant when workers had higher social support from their colleagues and supervisors. Conclusion: An investigation of the moderating effects of risk factors on neck pain might reveal the unexplained relationship between the risk factors for the development of neck pain in office workers. Therefore, the interest in prevention plans and treatments should involve a comprehensive understanding of the risk factors at workplace.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.14-21
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• 2005

By using PCR with nirS gene primers, three nirSharboring denitrifying bacteria (strain N6, strain N23, and strain R13) were newly isolated from activated sludge of a weak municipal wastewater treatment plant. Small-subunit rRNA gene-based analysis indicated that strain N6, strain N23, and strain R13 were closely related to Arthrobacter sp.,Staphylococcus sp., and Bacillus sp., respectively. In an attempt to identify their roles in biological nitrate and nitrite removal from sewage, we investigated their specific denitrification rates (SDNRs) for $NO_-^3$ - and $NO_-^2$ - in various cultures. All purecultures of each isolated nirS-harboring bacterial strain could remove $NO_-^3$ - and $NO_-^2$ - simultaneously in high efficiency, and the carbon requirements for $NO_-^3$ - removal of strain N6 and strain R13 were effectively low at 3.1 and 4.1 g COD/g $NO_3N$, respectively. In the case of mix-cultures of the strains (N6+N23, N6+R13, N23+R13, and N6+N23+R13), their SDNRs for $NO_-^3$ - were also effective, and their carbon requirements for $NO_-^3$ - removal were also effective at 3.0- 3.8 g COD/g NO3N. However, all tested mix-cultures accumulated $NO_-^2$ - in their culture media. On the other hand, the continuous culture of activated sludge mixed with strain N6 showed no significant increase of $NO_-^3$ - removal in comparison with strain N6's pure culture. These results suggest that nitrate and nitrite removal in biological wastewater treatment might be dependent on complicated bacterial interactions, including several effective denitrifying bacteria isolated in this study, rather than the specific bacterial types present and the number of bacterial types in activated sludge.

• Computers and Concrete
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• 제6권5호
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• pp.377-390
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• 2009

In this paper an improved one-dimensional frame element for modelling of reinforced concrete beams and columns subjected to impact is presented. The model is developed in the framework of a flexibility fibre element formulation that ignores the shear effect at material level. However, a simple shear cap is introduced at section level to take account of possible shear failure. The effect of strain rate at the fibre level is taken into account by using the dynamic increase factor (DIF) concept for steel and concrete. The capability of the formulation for estimating the element response history is demonstrated by some numerical examples and it is shown that the developed 1D element has the potential to be used for dynamic analysis of large framed structures subjected to impact of air blast and rigid objects.

• Smart Structures and Systems
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• 제4권2호
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• pp.137-152
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• 2008

The work presented in this paper includes material characterisation and an investigation of suitability in seismic dampers for two commercially available NiTi-alloys, along with a numerical analysis of a new damper system employing composite NiTi-wires. Numerical simulations of the new damper system are conducted, using Brinson's one-dimensional constitutive model for shape memory alloys, with emphasis on the system's energy dissipation capabilities. The two alloys tested showed some unwanted residual strain at temperatures higher than $A_f$, possibly due to stress concentrations near inclusions in the material. These findings show that the alloys are not ideal, but may be employed in a seismic damper if precautions are made. The numerical investigations indicate that using composite NiTi-wires in a seismic damper enhances the energy dissipation capabilities for a wider working temperature range.

• 대한기계학회논문집
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• 제18권1호
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• pp.184-192
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• 1994

The parameters such as Richardson numbers or stability parameters are widely used to account for the extra straining effects due to three-dimensionality, curvature, rotation, swirl and others arising in paractical complex flows. Existing expressions for the extra strain in turbulence models such as $k-{\epsilon}$ models, however, do not satisfy the tensor invariant condition representing the coordinate indifference. In the present paper, considering the characteristics of both the mean strain rate and the mean vorticity, a new parameter to deal with the extra straining effects is proposed. The new parameter has a simple form and satisfies the tensor invariant condition. A semi-quantitative analysis between the present and previous parameters for several typical complex flows suggests that the newly proposed parameter is more general and adequate in representing the extra straining effects than the previous ad-hoc parameters.

• 한국버섯학회지
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• 제8권1호
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• pp.6-10
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• 2010

볏짚버섯속 유망버섯인 차신고버섯은 현재까지 1종만이 품종으로 등록되어 있는 실정으로 국내 고유품종 확보 및 버섯재배품종 다양화에 기여하고자 품종육성 연구를 수행한 결과, 차신고버섯 신품종 '다산'의 균사생장적온은 $25{\sim}30^{\circ}C$이었으며 탄소원으로 glucose(maltose), 질소원으로 ammonium chloride(pepton)를 사용 시 균사생장 및 균사밀도가 우수하였고 탄소원과 질소원 무첨가 시 균사는 생장하였으나 균사의 밀도가 비교적 낮았다. 또한 버섯발생 특성은 신품종 "다산"이 초발이 소요일수, 수확 소요일수 및 수량은 각각 12~13일, 6~8일, 118.2g 으로 진향품종에 비해 다소 발이가 늦은 편이나 수량성은 양호하였다. 또한 "다산" 품종은 갓의 색깔은 대조품종 보다 진하고 갓의 직경은 작았으며 대의 길이는 길고 갓의 직경이 작은 자실체 특성을 가지고 있었다.

• Journal of Plant Biotechnology
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• 제45권4호
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• pp.328-332
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• 2018

Soybean [Glycine max (L.) Merr.] seed is an important dietary source of protein, oil, carbohydrate, isoflavone and other various nutrients for humans and animals. However, there are anti-nutritional factors in the raw mature soybeans. Kunitz trypsin inhibitor (KTI) protein and stachyose are the main anti-nutritional factors in soybean seed. The ${\alpha}^{\prime}$-subunit of ${\beta}$-conglycinin protein exhibit poor nutritional and food processing properties. The genetic removal of the KTI and ${\alpha}^{\prime}$-subunit proteins will improve the nutritional value of the soybean seed. The objective of this research was to develop a new soybean strain with KTI and ${\alpha}^{\prime}$-subunit protein free ($titicgy_1cgy_1$ genotype) and proper agronomic traits. A breeding population was developed from the cross of the Bl-1 and 15G1 parents. A total of 168 $F_2$ seeds from the cross of the BL-1 and 15G1 parents were obtained. The segregation ratios of 9: 3: 3: 1 ($104Ti\_Cgy_{1\_}:\;30Ti\_cgy_1cgy_1:\;21cgy_1cgy_1Ti\_:\;13titicgy_1cgy_1$) between the Ti and $Cgy_1$ genes in the $F_2$ seeds were observed (${\chi}^2=5.12$, P=0.5-0.10). Two $F_4$ plant strains with proper agronomical traits and $titicgy_1cgy_1$ genotype (free of both KTI and ${\alpha}^{\prime}$-subunit protein) were selected and harvested. 2 strains (S1 and S2) had yellow seed coats and hilum. The plant height of the S1 strain was 65 centimeters. The 100-seed weight was 29.2 g. The plant height of the S2 strain was 66 centimeters and 100-seed weight was 26.2 g. The two strains selected in this research will be used to improve the new cultivar that will be free of the KTI and ${\alpha}^{\prime}$-subunit proteins.

• Asian-Australasian Journal of Animal Sciences
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• 제32권2호
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• pp.241-248
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• 2019

Objective: To isolate and identify new methanogens from the rumen of Holstein steers in Korea. Methods: Representative rumen contents were obtained from three ruminally cannulated Holstein steers ($793{\pm}8kg$). Pre-reduced media were used for the growth and isolation of methanogens. Optimum growth temperature, pH, and sodium chloride (NaCl) concentration as well as substrate utilization and antibiotic tolerance were investigated to determine the physiological characteristics of the isolated strain. Furthermore, the isolate was microscopically studied for its morphology. Polymerase chain reaction of 16S rRNA and mcrA gene-based amplicons was used for identification. Results: One strain designated as KOR-2 was isolated and found to be a non-motile irregular coccus with a diameter of 0.2 to $0.5{\mu}m$. KOR-2 utilized $H_2+CO_2$ and formate but was unable to metabolize acetate, methanol, trimethylamine, 2-propanol, and isobutanol for growth and methane production. The optimum temperature and pH for the growth of KOR-2 were $38^{\circ}C$ and 6.8 to 7.0, respectively, while the optimum NaCl concentration essential for KOR-2 growth was 1.0% (w/v). KOR-2 tolerated ampicillin, penicillin G, kanamycin, spectromycin, and tetracycline. In contrast, the cell growth was inhibited by chloramphenicol. Phylogenetic analysis of 16S rRNA and mcrA genes revealed the relatedness between KOR-2 and Methanoculleus bourgensis. Conclusion: Based on the physiological and phylogenetic characteristics, KOR-2 was thought to be a new strain within the genus Methanoculleus and named Methanoculleus bourgensis KOR-2.