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  • Author or Editor: D.R. Gao x
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Abstract

Phase change materials (PCM) have been extensively scrutinized for their widely application in thermal energy storage (TES). Paraffin was considered to be one of the most prospective PCMs with perfect properties. However, lower thermal conductivity hinders the further application. In this letter, we experimentally investigate the thermal conductivity and energy storage of composites consisting of paraffin and micron-size graphite flakes (MSGFs). The results strongly suggested that the thermal conductivity enhances enormously with increasing the mass fraction of the MSGFs. The formation of heat flow network is the key factor for high thermal conductivity in this case. Meanwhile, compared to that of the thermal conductivity, the latent heat capacity, the melting temperature, and the freezing temperature of the composites present negligible change with increasing the concentration of the MSGFs. The paraffin-based composites have great potential for energy storage application with optimal fraction of the MSGFs.

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Molecular markers are important tools that have been used to identify the short arm of rye chromosome 1R (1RS) which contains many useful genes introgressed into wheat background. Wheat expressed sequence tag (EST) sequences are valuable for developing molecular markers since ESTs are derived from gene transcripts and more likely to be conserved between wheat and its relative species. In the present study, 35 sequence-tagged site (STS) primers were designed based on EST sequences distributed on homology group 1 chromosomes of Triticum aestivum and used to screen specific markers for chromosome 1RS of Secale cereale . Two primer pairs different from the early studies, STS WE3 , which amplified a 1680-bp and a 1750-bp fragment, and STS WE126 , which produced a 850-bp fragment from rye genome, were proved to be specific to chromosome 1RS since the corresponding fragments were only amplified from 1R chromosome addition line and wheat-rye lines with chromosome 1RS, but not from wheat-rye 2R-7R chromosome addition lines and the other lines lacking chromosome 1RS. Eleven wheat-rye lines derived from ‘Xiaoyan 6’ and ‘German White’ were used to test the presence of specific markers for 1RS. The specific fragments of 1RS were amplified in 4 wheat-rye lines, but not in the other lines. The testing results using EST-STS markers of 1RS were consistent with those obtained from fluorescence in situ hybridization (FISH), suggesting that these markers specific to 1RS could be used in marker-assisted selection (MAS) for incorporating 1RS into wheat cultivars in breeding.

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Shewanella putrefaciens supernatant was found to increase the virulence factors of Vibrio parahaemolyticus by efficiently degrading its acylhomoserine lactone (AHL). To further reveal the regulation mechanism and its key degrading enzyme, a potential AHL-degrading enzyme acylase (Aac) from S. putrefaciens was cloned, and the influences of temperature, pH, protein modifiers, and metals on Aac were tested. Aac was significantly influenced by temperature and pH, and exhibited the highest AHL-degrading activity at temperatures of 37 °C and pH of 8. Mg2+ and Fe2+ can further increase the AHL-degrading activity. 10 mM EDTA inhibited its activity possibly by chelating the co-factors (metals) required for Aac activity. Tryptophan and arginine were identified as key components for Aac activity that are critical to its AHL-degrading activity. This study provides useful information on Aac and for V. parahaemolyticus control.

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This study was conducted to compare structural development and biochemical accumulation of waxy and non-waxy wheat (NW) caryopses. The caryopses’ microstructure of the waxy wheat (WW) and NW cultivars at different developmental stages were observed under light, fluorescence, and scanning electron microscope. The results were as follows: Compared with NW,WWhad a shorter maturation duration, which was reflected in several following characteristics. Programmed cell death of the pericarp began earlier, and the chlorophyll-containing layer in the pericarp was smaller. Vacuoles in chalazal cells accumulated more tannins at different developmental stages. Starch granules and protein bodies in the endosperm showed a higher accumulation level in developing caryopses, and aleurone cells were larger in size with larger numbers of aleurone grains. An analysis of the element content indicated that the mineral elements Mg, P, K, and Ca exhibited a higher content, while the heavy elements Cr, Cd, and Pb exhibited a lower content in the aleurone layer.

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In the present work, fruits of Prangos platychlaena Boiss. ex Tchihat. ssp. platychlaena (Apiaceae) collected from eastern (sample A) and central (sample B) parts of Turkey were subjected to hydrodistillation to yield essential oils (EOs). The chemical composition of P. platychlaena ssp. platychlaena fruit oil was analyzed by gas chromatography–flame ionization detector (GC–FID) and gas chromatography–mass spectrometry (GC–MS) techniques. An unknown compound with m/z 178 [M]+ in high percentages was detected in both EOs (45.8% and 11.2% in samples A and B, respectively). Column chromatography on silica gel was subsequently followed by the sample A and yielded a new acetylenic derivative (1), which was characterized by spectroscopic techniques as (2S)- 3,5-nonadiyne-2-yl acetate. Samples A and B oils were characterized by a series of acetylenic derivatives like 3,5-nonadiyne (24.5% and 5.8% in A and B, respectively), (Z)-3,5-nonadiyne-7-ene (0.2% in A), and (E)-3,5-nonadiyne-7-ene (0.5% in A). Monoterpenes α-pinene (6.8% and 12.8%), α-phellandrene (0.1% and 17.1%), and β-phellandrene (4.2% and 22.4%) were found to be the major components in P. platychlaena ssp. platychlaena EOs in samples A and B, respectively. The components of P. platychlaena ssp. platychlaena EOs were separated on the overpressured layer chromatography (OPLC) plates, and the plates were subsequently subjected to direct-bioautography assays using three plant pathogens such as Colletotrichum acutatum, C. fragariae, and C. gloeosporioides; however, no antifungal activity was observed. Due to a high yield, sample A was evaluated for its repellent activity against female mosquito Aedes aegypti and attraction of sterile male Mediterranean fruit fly Ceratitis capitata. Sample A demonstrated good repellency against Ae. aegypti in human-based cloth patch bioassays and no attraction to C. capitata in short range bioassays.

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