• Macromolecular Research
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• v.15 no.4
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• pp.315-323
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• 2007

The present manuscript deals with the prediction of the lifetime of NBR compound based rubber gaskets for use as fuel cells. The material was investigated at 120, 140 and $160^{\circ}C$, with aging times from 3 to 600 h and increasing $H_2SO_4$ concentrations of 5, 6, 7 and 10 vol%. Both material and accelerated acid-heat aging tests were carried out to predict the useful life of the NBR rubber gasket for use as a fuel cell stack. To investigate the effects of acid-heat aging on the performance characteristics of the gaskets, the properties of the NBR rubber, such as crosslink density and elongation at break, were studied. The hardness of the NBR rubber was found to decrease with decreasing acid concentration at both $120\;and\;140^{\circ}C$, but at $160^{\circ}C$, the hardness of the NBR rubber increased abruptly in a very short time at different acid concentrations. The tensile strength and elongation at break were found to decrease with increases in both the $H_2SO_4$ concentration & temperature. The observed experimental results were evaluated using the Arrhenius equation.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.47-51
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• 2007

The present paper reports the life time prediction of Acrylonitrile-Butadiene rubber (NBR) fuel cell gasket materials as a function of operational variables like acid concentration, ageing time and temperature. Both material and accelerated acid-heat aging tests were carried out to predict the useful life of the NBR rubber gasket for use as a fuel cell stack. The acid ageing of the gasket compounds has been investigated at 120, 140 and $160^{\circ}C$, with aging times from 3 to 600 h and increasing acid ($H_2SO_4$) concentrations of 5, 6, 7 and 10 vol%. Material characteristics the gas compound such as cross-link density, tensile strength and elongation at break were studied. The hardness of the NBR rubber was found to decrease with decreasing acid concentration at both 120 and $140^{\circ}C$, but at $160^{\circ}C$ interestingly the hardness of the NBR rubber increased abruptly in a very short time at different acid concentrations. The tensile strength and elongation at break were found to decrease with increase in both the acid concentrate ion & temperature. The life time of the compounds were evaluated using the Arrhenius equation.

• Journal of Plant Biotechnology
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• v.5 no.1
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• pp.69-77
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• 2003

Brassinosteroids are known to promote cell elongation in a wide range of plant species but their effect on cell division has not been extensively studied. The effect of brassinolide on the kinetics and final division frequencies of regenerating petal protoplasts of Petunia hybrida Vilm v. Comanche was examined. Under optimal auxin and cytokinin conditions, 10-100 nM brassinolide not only reduced the time of first cell division by 4.5 days but also altered the final division frequencies after 10 days of culture. One micromolar brassinolide showed the same acceleration of first cell division but inhibited the final division frequency by approximately 9%. Under sub-optimal auxin conditions, 10-100 nM brassinolide accelerated the first cell division, but no significant increase in the 8-10 days final division frequencies. Isolated protoplasts may provide a useful model system for the investigation of the molecular mechanisms of brassinosteroid action on cell division and proliferation in higher plants.

• Journal of Plant Biotechnology
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• v.5 no.1
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• pp.63-67
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• 2003

Brassinosteroids are known to promote cell elongation in a wide range of plant species but their effect on cell division has not been extensively studied. The effect of brassinolide on the kinetics and final division frequencies of regenerating petal protoplasts of Petunia hybrida Vilm v. Comanche was examined. Under optimal auxin and cytokinin conditions, 10-100 nM brassinolide not only reduced the time of first cell division by 4.5 days but also altered the final division frequencies after 10 days of culture. One micromolar brassinolide showed the same acceleration of first cell division but inhibited the final division frequency by approximately 9%. Under sub-optimal auxin conditions, 10-100 nM brassinolide accelerated the first cell division, but no significant increase in the 8-10 days final division frequencies. Isolated protoplasts may provide a useful model system for the investigation of the molecular mechanisms of brassinosteroid action on cell division and proliferation in higher plants.

• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.622-629
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• 2018

Expansins are cell wall proteins that mediate cell wall loosening and promote specific tissue and organ morphogenesis in plants and in some microorganisms. Unlike plant expansins, the biological functions of fungal expansin-like proteins have rarely been discussed. In the present study, an expansin-like protein-encoding fvexpl1 gene, was identified from Flammulina velutipes by using local BLAST. It consisted of five exons with a total length of 822 bp. The deduced protein FVEXPL1 contained 274 amino acids with a predicted molecular mass and isoelectric point of 28,589 Da and pH 4.93, respectively. The first 19 amino acids from the N terminal are the signal peptide. Phylogenetic analysis and multiple protein alignment indicated FVEXPL1 was an expansin-like protein. The expression level of fvexpl1 gene in the stipe was significantly higher than that in the mycelia, primordia, and cap. However, the expression level of fvexpl1 gene was significantly higher in the fast elongation region of the stipe as compared with the slow elongation region. Expression analysis indicated that fvexpl1 gene might have an auxiliary role in the stipe morphogenesis of F. velutipes.

• Journal of Plant Biology
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• v.35 no.1
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• pp.77-84
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• 1992

In view of the well-established role of protein kinase C effector element in signal transduction of animal systems, the possibility of diacylglycerol (DAG) and its analog 12-O-tetradecanoylphorbol13-acetate (TPA) having an effect on auxin-induced growih of com coleoptiles was explored. Both DAG and TP A were found to promote cell elongation in the coleoptile tissue_ Treatment of tissue with these protein kinase C-activating agents resulted in increase in the growth rate over the control by about 300%. When 1M was applied to TPA-pretreated coleoptiles. auxin effect appeared synergistic. Morever. coleoptile growth was found to be inhibited by staurosporine and methylated TPA, both of which are known to specifically inhibit protein kinase C. Electrophoretic and autoradiographic patterns of soluble proteins from the coeoptiles indicated that either 1M or TPA tereatment resulted in increased phosphorylation of certain proteins of 205 Kd. 66 Kd and 32 Kd in size. The results obtained from the present work suggest that protein kinase C may be associated with auxin action on cell elongation in the corn coleoptile segments.gments.

• The Plant Pathology Journal
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• v.39 no.1
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• pp.123-135
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• 2023

Previously, Pseudomonas plecoglossicida YJR13 and Pseudomonas putida YJR92 from a sequential screening procedure were proven to effectively control Phytophthora blight caused by Phytophthora capsici. In this study, we further investigated the anti-oomycete activities of these strains against mycelial growth, zoospore germination, and germ tube elongation of P. capsici. We also investigated root colonization ability of the bacterial strains in square dishes, including cell motility (swimming and swarming motilities) and biofilm formation. Both strains significantly inhibited mycelial growth in liquid and solid V8 juice media and M9 minimal media, zoospore germination, and germ tube elongation compared with Bacillus vallismortis EXTN-1 (positive biocontrol strain), Sphingomonas aquatilis KU408 (negative biocontrol strain), and MgSO₄ solution (untreated control). In diluted (nutrient-deficient) V₈ juice broth, the tested strain populations were maintained at >10⁸ cells/ml, simultaneously providing mycelial inhibitory activity. Additionally, these strains colonized pepper roots at a 10⁶ cells/ml concentration for 7 days. The root colonization of the strains was supported by strong swimming and swarming activities, biofilm formation, and chemotactic activity towards exudate components (amino acids, organic acids, and sugars) of pepper roots. Collectively, these results suggest that strains YJR13 and YJR92 can effectively suppress Phytophthora blight of pepper through direct anti-oomycete activities against mycelial growth, zoospore germination and germ tube elongation. Bacterial colonization of pepper roots may be mediated by cell motility and biofilm formation together with chemotaxis to root exudates.

• Fashion & Textile Research Journal
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• v.10 no.2
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• pp.236-241
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• 2008

Hair manicure is usually and widely operated in the area of hair-dyeing by the reason that acidic hair color is less damaged and more stable than other chemical color treatment. However, there is no an in-depth study to prove them. This study purposes to provide basic resources for effectively using products of hair manicure by experiments on Physical Properties of Hair. Hair of one healthy woman in mid-20's, Level 4, was sampled for experiments. For the tests, hair samples were classified by the frequency of hair manicure treatment The control group(a), once treatment(b), twice(c), three times(d), four times(e) and five times(f). The results were measured with Scanning Electron Microscopy(SEM) and Tensile Strength and Elongation test. The lower Values of Tensile Strength according to repeated hair manicure treatment. Elongation is not affected by the frequency of hair manicure treatment. There was no remarkable change of hair surface in once(b) and twice(c) treatment. The change of hair surface which was able to judge by cuticle layers looseness, tunics and the transformation of cuticle cell were observed in the hair samples operating more than three times(d) of hair manicure treatment.

• Journal of Plant Biology
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• v.35 no.4
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• pp.425-429
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• 1992

Cell elongation is known to be promoted by ethylene in petioles of Ranunculus sceleratus. Treatment of petiole segments with spermine resulted in an inhibition of cell elongation and of ethylene biosynthesis in the presence of applied auxin. Dose response curve for the spermine inhibition of auxin-induced ethylene production appeared similar to that of ACC-based ethylene production suggesting that the polyamine inhibits ethylene biosynthesis by blocking the conversion of ACC to etylene. Auxin-induced ethylene production was significantly promoted by treatment of the tissue with either DFMA or DFMO. specific inhibitors of polyamine biosynthesis. Increased level of ethylene production by DFMA was found to be completely abolished by application of exogenous spermine at a high concentration. These results indicate that endogenous spermine plays a regulatory role in the growth response of Ranunculus petioles to auxin and ethylene.hylene.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.293-296
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• 1996

The present study was carried out to investigate the effect of Ni on germination, cell elongation, ${\alpha}-amylase$ activity, contents of chlorophyll and protein in radish were determined in the water culture. As the concentration of Ni was increased in the water culture, germination of radish was 55% by Ni 10 mg/kg and 30% by Ni 20 mg/kg. The ratio of cell elongation injury was 50%, by two days after Ni 20 mg/kg treatment. The injury ratio of ${\alpha}-amylase$ activity was 45% in the same condition and as the time goes on, inhibition of ${\alpha}-amylase$ activity were slightly decreased. Contents of chlorophyll a and b were decreased two days after treatment and chlorophyll a was more inhibited than chlorophyll b. Also changes of the protein contents was slightly decreased. Activity of ${\alpha}-amylase$ was decreased at germination stage, contents of chlorophyll a and b were decreased at growing stage.