Mechanical, thermomechanical, and creep performance of CNT embedded epoxy at elevated temperatures: An emphasis on the role of carboxyl functionalization

2017 ◽  
Vol 134 (21) ◽  
Author(s):  
Dinesh Kumar Rathore ◽  
Rajesh Kumar Prusty ◽  
Bankim Chandra Ray
2014 ◽  
Vol 27 (6) ◽  
pp. 557-566 ◽  
Author(s):  
Shuai Hu ◽  
Xiaoying Zhou ◽  
Xiaoying Gu ◽  
Shulin Cao ◽  
Chengfang Wang ◽  
...  

Like many other filamentous ascomycetes, Fusarium graminearum contains two genes named CPK1 and CPK2 that encode the catalytic subunits of cyclic AMP (cAMP)-dependent protein kinase A (PKA). To determine the role of cAMP signaling in pathogenesis and development in F. graminearum, we functionally characterized these two genes. In addition, we generated and characterized the cpk1 cpk2 double and fac1 adenylate cyclase gene deletion mutants. The cpk1 mutant was significantly reduced in vegetative growth, conidiation, and deoxynivalenol production but it had increased tolerance to elevated temperatures. It was defective in the production of penetration branches on plant surfaces, colonization of wheat rachises, and spreading in flowering wheat heads. Deletion of CPK1 had no effect on perithecium development but the cpk1 mutant was defective in ascospore maturation and releasing. In contrast, the cpk2 mutant had no detectable phenotypes, suggesting that CPK2 contributes minimally to PKA activities in F. graminearum. Nevertheless, the cpk1 cpk2 double mutant had more severe defects in vegetative growth and rarely produced morphologically abnormal conidia. The double mutant, unlike the cpk1 or cpk2 mutant, was nonpathogenic and failed to form perithecia on self-mating plates. Therefore, CPK1 and CPK2 must have overlapping functions in vegetative growth, differentiation, and plant infection in F. graminearum. The fac1 mutant was also nonpathogenic and had growth defects similar to those of the cpk1 cpk2 mutant. However, deletion of FAC1 had no effect on conidium morphology. These results indicated that CPK1 is the major PKA catalytic subunit gene and that the cAMP-PKA pathway plays critical roles in hyphal growth, conidiation, ascosporogenesis, and plant infection in F. graminearum.


2009 ◽  
Vol 66 (7) ◽  
pp. 1515-1519 ◽  
Author(s):  
Suchana Chavanich ◽  
Voranop Viyakarn ◽  
Thepsuda Loyjiw ◽  
Priyapat Pattaratamrong ◽  
Anchalee Chankong

Abstract Chavanich, S., Viyakarn, V., Loyjiw, T., Pattaratamrong, P., and Chankong, A. 2009. Mass bleaching of soft coral, Sarcophyton spp. in Thailand and the role of temperature and salinity stress. – ICES Journal of Marine Science, 66: 1515–1519. From June to October 2006 and 2007, mass bleaching of the soft coral, Sarcophyton spp., occurred for the first time in the upper Gulf of Thailand. Approximately 90% of the populations experienced extensive bleaching, and almost 95% of colonies were affected. Field observations also revealed that fragmentation of Sarcophyton spp. set in 1 month after the onset of bleaching. Some colonies started to recover to some extent by the end of July, with 95% of the population of Sarcophyton spp. recovering by October. Both acute and chronic trials were conducted to determine whether temperature and/or salinity triggered bleaching. In the acute tests, Sarcophyton spp. at 40°C and salinity 20 psu were completely bleached, and death occurred after 57 and 204 h, respectively. However, the colonies at 40 psu could survive through the experimental trial. In the chronic tests, Sarcophyton spp. died when exposed to 34°C, whereas complete bleaching and mortality of Sarcophyton spp. occurred at salinities of 10 and 49 psu. We conclude that elevated temperatures had a greater effect on the bleaching of Sarcophyton spp. than did salinity.


2005 ◽  
Vol 86 (1-2) ◽  
pp. 81-100 ◽  
Author(s):  
Ashley J. Watson ◽  
Arwel V. Hughes ◽  
Paul K. Fyfe ◽  
Marion C. Wakeham ◽  
Kate Holden-Dye ◽  
...  

1987 ◽  
Vol 7 (3) ◽  
pp. 1208-1216 ◽  
Author(s):  
D J Hurt ◽  
S S Wang ◽  
Y H Lin ◽  
A K Hopper

Saccharomyces cerevisiae strains carrying los1-1 mutations are defective in tRNA processing; at 37 degrees C, such strains accumulate tRNA precursors which have mature 5' and 3' ends but contain intervening sequences. Strains bearing los1-1 and an intron-containing ochre-suppressing tRNA gene, SUP4(0), also fail to suppress the ochre mutations ade2-1(0) and can1-100(0) at 34 degrees C. To understand the role of the LOS1 product in tRNA splicing, we initiated a molecular study of the LOS1 gene. Two plasmids, YEpLOS1 and YCpLOS1, that complement the los1-1 phenotype were isolated from the YEp24 and YCp50 libraries, respectively. YEpLOS1 and YCpLOS1 had overlapping restriction maps, indicating that the DNA in the overlapping segment could complement los1-1 when present in multiple or single copy. Integration of plasmid DNA at the LOS1 locus confirmed that these clones contained authentic LOS1 sequences. Southern analyses showed that LOS1 is a single copy gene. The locations of the LOS1 gene within YEpLOS1 and YCpLOS1 were determined by deletion and gamma-delta mapping. Two genomic disruptions of the LOS1 gene were constructed, i.e., an insertion of a 1.2-kilobase fragment carrying the yeast URA3 gene, los1::URA3, and a 2.4-kilobase deletion from the LOS1 gene, los1-delta V. Disruption or deletion of most of the LOS1 gene was not lethal; cells carrying the disrupted los1 alleles were viable and had phenotypes similar to those of cells carrying the los1-1 allele. Thus, it appears that the los1 gene product expedites tRNA splicing at elevated temperatures but is not essential for this process.


1996 ◽  
Vol 431 ◽  
Author(s):  
C. K. Narula

AbstractThe high cost of materials prepared by sol-gel processing and the loss of useful surface properties at elevated temperature has prevented the application of sol-gel processed materials in automotive exhaust reduction catalyst formulations. In this report, we briefly describe the important developments needed in the next generation automotive catalysts and the role of sol-gel processed materials. We will also discuss the application of heterometallic alkoxides as sol-gel precursors to achieve the molecular distribution of lanthanides and alkaline earths in alumina matrices needed for the stabilization of alumina based materials at elevated temperatures.


2018 ◽  
Vol 285 (1871) ◽  
pp. 20172547 ◽  
Author(s):  
Laura L. Hurley ◽  
Callum S. McDiarmid ◽  
Christopher R. Friesen ◽  
Simon C. Griffith ◽  
Melissah Rowe

For sexually reproducing species, functionally competent sperm are critical to reproduction. While high atmospheric temperatures are known to influence the timing of breeding, incubation and reproductive success in birds, the effect of temperature on sperm quality remains largely unexplored. Here, we experimentally investigated the impact of ecologically relevant extreme temperatures on cloacal temperature and sperm morphology and motility in zebra finches Taeniopygia guttata . We periodically sampled males exposed to 30°C or 40°C temperatures daily for 14 consecutive days. Following a 12-day (23°C) recovery period, birds were again exposed to heat, but under the alternate treatment (e.g. birds initially exposed to 40°C were exposed to 30°C). Elevated temperatures led to an increase in cloacal temperature and a reduction in the proportion of sperm with normal morphology; these effects were most notable under 40°C conditions, and were influenced by the duration of heat exposure and prior exposure to high temperature. Our findings highlight the potential role of temperature in determining male fertility in birds, and perhaps also in constraining the timing of avian breeding. Given the increased frequency of heatwaves in a warming world, our results suggest the need for further work on climatic influences on sperm quality and male fertility.


1968 ◽  
Vol 41 (5) ◽  
pp. 1300-1311 ◽  
Author(s):  
J. R. Creasey ◽  
D. B. Russell ◽  
M. P. Wagner

Abstract The addition of resoreinol plus hexamethylenetetramine and/or hydrated silicas to rubber compounds can result in increased adhesion to textiles, wire, and other rubber compounds. Silica prevents loss of adhesion on aging or at elevated temperatures. The increase in adhesion is due, depending on the system, to improved wetting and hydrogen-bonding between the rubber compound and the substrate to which it adheres.


1975 ◽  
Vol 97 (4) ◽  
pp. 289-297 ◽  
Author(s):  
B. Tomkins

The value of modelling the fatigue crack propagation process is discussed and current models are examined in the light of increasing knowledge of crack tip deformation. Elevated temperature fatigue is examined in detail as an area in which models could contribute significantly to engineering design. A model is developed which examines the role of time-dependent creep cavitation on the failure process in an interactive creep-fatigue situation.


1990 ◽  
Vol 68 (2) ◽  
pp. 340-345 ◽  
Author(s):  
Robert A. Pozzobon ◽  
J. M. Shaw ◽  
Sun Yushun

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