Degradation of Fatty Acid Phase-Change Materials (PCM): New Approach for Its Characterization.

The use of adequate thermal energy storage (TES) systems is an efficient way to achieve thermal comfort in buildings reducing the cooling and heating demand. Besides, deploy phase change materials (PCM) to meet and enhance the TES needs is highly effective and widely studied. In this paper, a study of the degradation of two fatty acids is presented, capric and myristic acids, in order to evaluate whether their thermo-physical properties are affected throughout time during service. This was carried out by means of two different types of thermal treatments: degradation at constant temperature (thermal stability test), 60 °C during 100 h and 500 h, and degradation with heating and cooling cycling (thermal cycling stability), between a temperature range from 15 °C to 70 °C with 0.5 °C/min ramp during 500 and 1000 cycles. Despite no significant changes were measured for myristic acid, experimental results revealed a decrease of melting enthalpy of 6.6% in capric acid thermally treated for 500 h. Evidences of chemical degradation were found that might explain the decrease in thermophysical properties during use.

DNA copy number profiling reveals different patterns of chromosomal instability within colorectal cancer according to the age of onset.

Chromosomal instability resulting in copy number alterations is a hallmark of colorectal cancer (CRC). However, few studies have attempted to characterize the chromosomal changes occurring in early-onset CRC in order to compare them with those taking place within the more extensively studied late-onset CRC subset. Our aim was to characterize the genomic profiles of these two groups of colorectal tumors and to compare them to each other. Array comparative genomic hybridization profiling of 146 colorectal tumors (60 early-onset and 86 late-onset) in combination with an unsupervised analysis was used to define common and specific copy number alterations. We found a number of important differences between the chromosomal instability profiles of each age subset. Thus, losses at 1p36, 1p12, 1q21, 9p13, 14q11, 16p13, and 16p12 were significantly more frequent in younger patients, whereas gains at 7q11 and 7q22 were more frequent in older patients. Moreover, the unsupervised analysis stratified the tumors into two clusters, each one of which was enriched in patients from one of the age subsets. Our findings confirm the existence of substantial differences between the chromosomal instability profiles of the two groups which are more important from a qualitative point of view. Further studies are needed to understand the clinicopathological implications of these dissimilarities.