Search Results
Gastrodia elata Blume polysaccharide (GEP) was extracted and then chemically characterised. Its antioxidant activity was evaluated in vitro and in vivo. The results of the in vitro investigation show that GEP consists of glucose with molecular weight of 875 185 Da and exhibits high hydroxyl radical scavenging, as well as 2,2-diphenyl-1- picrylhydrazyl activity and reducing capacity. For antioxidant activity in vivo, D-galactose-induced-aged mice were orally administered with three different doses of GEP over a period of 6 weeks. The administration of GEP dosedependently increased the body weight gain rates, liver and brain indices, superoxide dismutase and glutathione peroxidase activities, and malondialdehyde levels in the sera and brains of ageing mice. These results suggest that GEP exhibits high antioxidant activity and can retard human ageing associated with free radicals.
Summary Simulation of thermal ageing is an important part of qualification of materials designed for the use in nuclear power plants (NPP). According to standards, the simulation of long-term service thermal ageing is performed isothermally at elevated temperature using Arrhenius methodology. The samples or equipment are aged in thermal chamber, to bring them to the same state as after long-term service time. To proceed a reliable simulation, the testing parameters should be taken very carefully and the accelerator factors should not be too high. The testing temperature and time and the activation energy are the most important parameters. Determination of these factors and the limitations of their use in practice are discussed.
Abstract
The time-course of average age of members of the Russian Academy of Sciences in the XVIII–XIX centuries was analyzed. A long-term trend of academician aging was found, with its extrapolation correctly predicting the average age of the recent academicians. Although the lifespan was increasing as well and its effect can statistically explain the most part (up to 80%) of variance in the average age, it was not the only cause. Furthermore, its effect might be indirect (i.e. the increasing average age was not simply due to a longer lifespan of elected members), since average membership span was slightly decreasing. At least a part of the trend was caused by a growth of competition for election since it was negatively correlaten with a contemporaneous number of members (at given lifespan and historical year). Comparison of three groups (full members, corresponding members and foreign members), differing in competition level, supports this suggestion. Besides the history of science, the results may be useful for dealing with the problem of growing age of the scientific establishment.
population, and the World Bank estimates that the annual global economic cost to manage CHF patients is $10.8 billion [ 1 , 3 ]. The prevalence of heart failure is related to age. A survey conducted by the American College of Cardiology shows that the prevalence
Introduction Ageing societies and COVID-19 pandemic A main demographic phenomenon of the developed world is the ageing of the population. Since 1950, the number of people aged 60 years and
Jager, R. D., Mieler, W. F., Miller, J. W.: Age-related macular degeneration. N. Engl. J. Med., 2008, 358 , 2606–2617. Miller J. W
Árva-Sós, E., L. Ravasz-Baranyai 1992: A Mecsek és Villányi hegység között feltört telérkőzetek K/Ar kora (K/Ar age of the Cretaceous dike rocks risen in the Mecsek and Villány Mts [SW Hungary]). (In Hung. with
Abstract
The long-term environmental ageing of conductive composite films containing ethylene-co-vinyl-acetate (EVA) copolymer and a complex of polyaniline (PANI) and dodecylbenzenesulfonic acid (DBSA) was studied by using differential scanning calorimetry (DSC). We assume that both phase separation and crosslinking of PANI main chains occur in the systems. On the other hand, the competition between PANI–DBSA complex self-organization and crystallization of EVA matrix result in structural changes and formation of continuous conductive network, responsible for significantly increased (ca five orders of magnitude) electrical conductivity of the aged films.
Abstract
An extensive study has been carried out on aqueous ‘extremely diluted solutions’ (EDS). The employed experimental methodologies were well established physico-chemical techniques: flux calorimetry, conductometry, pH-metry, e.m.f. of suitable galvanic cell. The obtained results show that the preparation procedure significantly alters the physico-chemical behaviour of such solutions. Moreover, the analysis of the experimental data vs. the ‘arrow of time’ turned out to be astonishingly important. In fact some measured physico-chemical parameters evolve with time. Some experimentally measurable physico-chemical properties of the solvent water were largely affected by both time and the ‘life path’ of the samples. In particular, we evidenced two new experimental phenomena characterizing the EDS: the presence of a series of maximums in the measured electrical conductivity vs. the sample age; the dependence of said maximums on the volume of the EDS during its ageing. All of these new experimental results clearly suggest the presence of an extended and ‘ordered’ dynamics involving the whole of the water molecules in the liquid. A temporal evolution, featuring three maximums in the course of four years of ageing and the dependence on the ageing volumes do not fit the framework of classical thermodynamics. It therefore seems appropriate to interpret these phenomena on the basis of the thermodynamics of dissipative structures, which are far from equilibrium systems.
2005 Age differences in exposure and reactions to interpersonal tensions: A daily diary study Psychology and Aging 20 330 340
