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Most of red wine's health benefits are attributed to polyphenols, which can express different biological effects. During ageing process, numerous chemical reactions occur, alternating phenolic composition of wine. Therefore, this paper focused on the influence of ageing on the evolution of wine phenolics (phenolic acids, flavonoids, stilbenes, and anthocyanins). Wines from 4 local grape varieties (Frankovka, Portugieser, Probus, and Rumenika) were analysed after 1 month and 4 years of ageing. Monomeric anthocyanin and total phenolic contents and antioxidative potential in aged wines were also determined. Among tested phenolics, main components in aged wines remained gallic acid (2.16–19.55 mg l−1) and catechin (8.39–37.21 mg l−1). The most prominent changes of analysed phenolic compounds during ageing were observed for p-coumaric acid (from +173.3% to +763.1%) and malvidin-3-glucoside (from +173.3% to +763.1%). Wine from Rumenika variety maintained the highest content of individual phenols after ageing. Additionally, aged wines had very low content of monomeric anthocyanins. Significant correlation (r= −0.93, P<0.05) between total phenolic content and IC50 values in aged wines was also noticed. Obtained results provide useful information about the quality preservation during aging and storage of these products.
paper, the result is statistically constant, as we shall see below. Let us call that index an a -index for “age independent”. After deriving the h -index, it takes about 10 s to derive the a -index. Analysis I used data
Abstract
The ageing characteristics of pyrotechnic compositions are influenced not only by temperature, but also by surrounding effects as humidity and vibrations. In this paper the thermal stability of the pyrotechnic system magnesium–sodium nitrate will be investigated. In an inert helium atmosphere two steps of mass loss, which were not completely separated from each other, were observed in the temperature range from 65 to 265C: a mass loss of about 15% between 65 and 160C and about 34% between 160 and 265C. It is assumed that these two steps are caused by different processes. The separation between the two steps was not or hardly detectable for measurements that were performed in a nitrogen atmosphere. Using MS and FTIR (mass spectrometry/Fourier transform infrared spectroscopy) the evolved gases were analysed. Only above about 170C evolving gases were detected (which means that during the first step no gases were detectable). The detected gas mainly consists of CO2, CO and N2O, with smaller amounts of NO2, NO and possibly HCN. A third step of mass loss (8–9%) was observed above 314C. The process which caused this step of mass loss is considered not to contribute significantly to the ageing of the material at much lower temperatures of maximum 80C, which is of interest in view of the use of the materials. Kinetic parameters for the processes which caused the first and the second step of mass loss were evaluated from kinetic analysis of the measured TG curves. By using these results the conversion can be predicted as a function of time and temperature. However, it must be considered that the inaccuracy of the predictions increases if the temperature for which the prediction is calculated is further away from the temperature at which the experiments were performed. This is caused by the exponential form of the kinetic equations. The calculations show that in particular the reaction which causes the first step of mass loss can run relatively quickly in the temperature range 25–80C, which could result in ageing of the material during storage at these conditions. The reaction which causes the second step of mass loss clearly runs at a much lower rate.
Touchette, E., Petit, D., Tremblay, R. E., et al.: Associations between sleep duration patterns and overweight/obesity at age 6. Sleep, 2008, 31 , 1507–1514. Tremblay R. E. Associations
Summary A procedure for the extrapolation of accelerated thermo-oxidative ageing tests to lower temperatures is proposed. The procedure involves a deconvolution of the global process into high- and low-temperature components where the extrapolation to low temperatures is carried out using the low-temperature component. The method was tested on stabilized and unstabilized polyisoprene rubber and was found to produce realistic estimations of the length of the induction period of oxidation so giving a more accurate estimation of the service life. However, to obtain the low-temperature values of the adjustable kinetic parameters, very low heating rates are required (0.04 K min-1, 0.1 K min-1) making the measurement process time consuming. Using this method, more realistic estimates of the durability of a material are obtained.
; 1775: 138–162. 9 Pal S, Tyler JK. Epigenetics and aging. Sci Adv. 2016; 2: e1600584. 10 Clouaire T, Stancheva I. Methyl-CpG binding proteins: specialized
Abstract
The physical ageing characteristics of glucose, fructose, and their mixtures were studied using standard differential scanning calorimetry (DSC). The inflection, onset, midpoint,half-height, and endpoint glass transition temperature (T
g), fictive temperature (T
f), and relaxation enthalpy (
H) were measured as a function of ageing time. The relationship between
H and T
f was evaluated. The time dependence of
H was fit using the Cowie and Ferguson model. The ageing rate was expressed in terms of the average relaxation time (<
>) and the entropy production (P). It was found that the fructose component decreased the rate of ageing of the mixtures.
III Comparative Health Sciences Symposium: “Ageing in a human way”
Semmelweis University Faculty of Health Sciences, Budapest, Hungary
developments, innovative methods, and new research programmes, as well as to promote professional discussion. The next symposium will be held in Budapest, Hungary, on December 14, 2018. The theme of this symposium is “Ageing in a human way” covering
the heavier chalcogen atoms (S, Se, Te), which are the main constituents of their covalent networks. However, chalcogen-rich glasses possess a pronounced physical aging effect under ambient conditions hindering their wide use for several applications
associated with fear of falling in community-dwelling older people? Age Ageing . 2014 ; 43 ( 1 ): 76 – 84 . 10.1093/ageing/aft154 3. Population Division . World Population Prospects 2019, Online Edition
