Adaptive evolution of the human fatty acid synthase gene: Support for the cancer selection and fat utilization hypotheses?

Cancer may act as the etiological agent for natural selection in some genes. This selective pressure would act to reduce the success of neoplastic lineages over normal cell lineages in individuals of reproductive age. In addition, humanâs relatively larger brain and longer lifespan may have also acted as a selective force requiring new genotypes. One of the most important proteins in both processes is the fatty acid synthase (FAS) gene involved in fatty acid biosynthesis. Avariety of other proteins, including PTEN, MAPK1, SREBP1, SREBP2 and PI are also involved in the regulation of fatty acid biosynthesis. We have specifically analysed variability in selective pressure across all these genes in human, mouse and other vertebrates.We have found that the FAS gene alone has signatures indicative of adaptive evolution.We did not find any signatures of adaptive evolution in any of the other proteins. In the FAS gene, we have detected an excess of non-synonymous over synonymous substitutions in approximately 6% of sites in the human lineage. Contrastingly, the substitution process at these sites in other available vertebrates and mammals indicates strong purifying selection. This is likely to reflect a functional shift in human FAS and correlates well with previously observed changes in FAS biochemical activities. We speculate that the role played by FAS either in cancer development or in human brain development has created this selective pressure, although we cannot rule out the various other functions of FAS

Occurrence of and Reasons for "Missing Events" in Mobile Dietary Assessments : Results From Three Event-Based Ecological Momentary Assessment Studies

Background: Establishing a methodology for assessing nutritional behavior comprehensively and accurately poses a great challenge. Mobile technologies such as mobile image-based food recording apps enable eating events to be assessed in the moment in real time, thereby reducing memory biases inherent in retrospective food records. However, users might find it challenging to take images of the food they consume at every eating event over an extended period, which might lead to incomplete records of eating events (missing events).Objective: Analyzing data from 3 studies that used mobile image-based food recording apps and varied in their technical enrichment, this study aims to assess how often eating events (meals and snacks) were missed over a period of 8 days in a naturalistic setting by comparing the number of recorded events with the number of normative expected events, over time, and with recollections of missing events.Methods: Participants in 3 event-based Ecological Momentary Assessment (EMA) studies using mobile image-based dietary assessments were asked to record all eating events (study 1, N=38, 1070 eating events; study 2, N=35, 934 eating events; study 3, N=110, 3469 eating events). Study 1 used a basic app; study 2 included 1 fixed reminder and the possibility to add meals after the actual eating events occurred instead of in the moment (addendum); and study 3 included 2 fixed reminders, an addendum feature, and the option to record skipped meals. The number of recalled missed events and their reasons were assessed by semistructured interviews after the EMA period (studies 1 and 2) and daily questionnaires (study 3).Results: Overall, 183 participants reported 5473 eating events. Although the momentary adherence rate as indexed by a comparison with normative expected events was generally high across all 3 studies, a differential pattern of results emerged with a higher rate of logged meals in the more technically intensive study 3. Multilevel models for the logging trajectories of reported meals in all 3 studies showed a significant, albeit small, decline over time (b=−.11 to −.14, PsConclusions: Three different indicators (normative, time stability, and recalled missing events) consistently indicated missing events. However, given the intensive nature of diet EMA protocols, the effect sizes were rather small and the logging trajectories over time were remarkably stable. Moreover, the individual’s actual state and context seemed to exert a greater influence on adherence rates than stable individual differences, which emphasizes the need for a more nuanced understanding of the factors that affect momentary adherence.publishe

Crystallization kinetics of PCL and PCL–glass composites for additive manufacturing

The non-isothermal crystallization kinetics of polycaprolactone (PCL) and PCL–glass composites, used in fused filament fabrication (FFF), was investigated. Films of PCL and PCL reinforced with powders of a bioactive glass, from the CaO.P2O5.MgO.SiO2 system, were prepared by solvent casting process. Crystal structure of the samples was examined by X-ray diffraction (XRD), and thermal properties were assessed by differential scanning calorimetry (DSC), at different cooling rates (5, 10, 15 and 20 C min-1). The DSC curves of non-isothermal crystallization showed a significant dependence of crystallinity (Xc) on the cooling rate. The relevant crystallization kinetic parameters were determined from DSC traces applying a combination of Avrami and Ozawa methods (Mo’s method), Jeziorny method and Friedman method. It was observed that the presence of inorganic particles within the polymeric matrix clearly influenced the composite crystallization. The addition of glass particles allowed a decrease in Xc and accelerated the PCL crystallization rate. The slower cooling rates tested proved to be suitable for the biofabrication of PCL–glass composites by FFF techniques.publishe