The solubility and dissolution behaviour of A- and B-type crystals of short chain amylose were measured both directly and using differential scanning calorimetry in the temperature range 30-110 degrees C. Dissolution in the calorimeter was affected by super-heating to the extent of 24-28 degrees C. Following trends previously found by calorimetry the B-type crystal polymorph was more soluble than the A-type. Analysis of the chain composition of the dissolved material revealed a preferential solubilisation of the short chains at the lower temperatures. The solubility of both crystal polymorphs and the magnitude of the preferential solubilisation effect was reduced in the presence of 30% w/w sucrose. A comparison of calorimetric measurements of crystal dissolution and the gelatinisation of native granular waxy maize and potato starches found some broad similarities, such as transition temperatures and their composition dependence, and some differences, such as the relatively narrow temperature range of granular gelatinisation, which reflects its cooperative nature.
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http://dx.doi.org/10.1016/j.carres.2004.11.006 | DOI Listing |
Heliyon
January 2025
Department of Physics, Facility of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
The influence of variations in indium concentration and temperature on threshold current density (J) in In Ga As/GaAs ( = 0, 0.8 and 0.16) quantum dot (QD) laser diodes - synthesized via molecular beam epitaxy (MBE) with three distinct indium concentrations on GaAs (001) substrates - was meticulously examined.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
January 2025
Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, Prague 180 00, Czechia.
This work investigates the surface chemistry of the Ru/CeO catalyst under varying pretreatment conditions and during the oxidation of propane, focusing on both dry and humid environments. Our results show that the Ru/CeO catalyst calcined in O at 500 °C initiates propane oxidation at 200 °C, achieves high conversion rates above 400 °C, and demonstrates almost no change in activity in the presence of water vapor across the entire studied temperature range of 200-500 °C. Prereduction of the oxidized Ru/CeO catalyst in H significantly enhances its activity, though this enhancement diminishes at higher temperatures.
View Article and Find Full Text PDFFor about 100 years, the shake flask has been established for biotechnological cultivations as one of the most important cultivation systems in early process development. Its appeal lies in its simple handling and highly versatile application for a wide range of cell types-from bacteria to mammalian cells. In recent decades, extensive research has been conducted on the shake flask, to not perform processes blindly but to gain a deeper understanding of the various process parameters, phenomena, and their impact on the process.
View Article and Find Full Text PDFJDS Commun
January 2025
School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061.
Prolonged exposure to high environmental temperatures results in an accumulated heat load that induces a heat stress (HS) response in dairy cattle. Heat stress compromises dairy farm profitability by reducing milk yield, altering milk composition, and hindering reproductive performance. The ability to alternate between carbohydrate and lipid sources for energy production is termed metabolic flexibility (Met Flex).
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan.
Control of the formation of liquid crystalline 3̄ gyroid phases and their nanostructures is critical to advance materials chemistry based on the structural feature of three-dimensional helical networks. Here, we present that introducing methyl side-group(s) and slight non-symmetry into aryloyl-hydrazine-based molecules is unexpectedly crucial for their formation and can be a new design strategy through tuning intermolecular interactions: the two chemical modifications in the core portion of the chain-core-chain type molecules effectively lower and extend the 3̄ phase temperature ranges with the increased twist angle between neighboring molecules along the network. The detailed analyses of the aggregation structure revealed the change in the core assembly mode from the double-layered core mode of the mother molecule (without methyl groups) to the single-layered core mode.
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