Particle transfer and fusion cross-section for Super-heavy nuclei in dinuclear system

Within the dinuclear system (DNS) conception, instead of solving Fokker-Planck Equation (FPE) analytically, the Master equation is solved numerically to calculate the fusion probability of super-heavy nuclei, so that the harmonic oscillator approximation to the potential energy of the DNS is avoided. The relative motion concerning the energy, the angular momentum, and the fragment deformation relaxations is explicitly treated to couple with the diffusion process, so that the nucleon transition probabilities, which are derived microscopically, are time-dependent. Comparing with the analytical solution of FPE, our results preserve more dynamical effects. The calculated evaporation residue cross sections for one-neutron emission channel of Pb-based reactions are basically in agreement with the known experimental data within one order of magnitude.Comment: 19 pages, plus 6 figures, submitted to Phys. Rev.

Mental health in the aged: prevalence, covariates and related neuroendocrine, cardiovascular and inflammatory factors of successful aging

<p>Abstract</p> <p>Background</p> <p>Although aging is accompanied by diminished functioning, many elderly individuals preserve a sense of well-being. While the concept of "successful aging" has been popular for many decades, little is known about its psycho-physiologic and endocrine underpinnings. KORA-Age is a population-based, longitudinal study designed to determine the prevalence of successfully aged men and women between 65 and 94 years old in the MONICA/KORA Augsburg cohort of randomly selected inhabitants. Specifically, we aim to identify predictors of successful aging and to elucidate bio-psychosocial mechanisms that maintain mental health and successful adaptation despite adverse experiences of life and aging.</p> <p>Methods/Design</p> <p>Components of successful aging were assessed in a telephone survey of 4,127 participants (2008-2009) enrolled in the MONICA/KORA cohort, on average, 13 years earlier. Psychosocial, somatic and behavioural predictors are used to determine factors that contribute to successful aging. An age-stratified random sub-sample (n = 1,079) participated in a personal interview where further psychological mechanisms that may underlie successful adaptation (resilience, social support, attachment) were examined. The interactions among neuroendocrine systems in the aging process are investigated by studying the cortisol/dehydroepiandrosterone-sulfate ratio, the level of insulin-like growth factor I, and oxytocin.</p> <p>Discussion</p> <p>Longitudinal determinants of successful aging can be assessed based on a follow-up of an average of 13 years. A comprehensive analysis of biological as well as physio-psychological information provides a unique opportunity to investigate relevant outcomes such as resilience and frailty in the elderly population.</p

3,4-Methylenedioxymethamphetamine (MDMA) neurotoxicity in rats: a reappraisal of past and present findings

RATIONALE: 3,4-Methylenedioxymethamphetamine (MDMA) is a widely abused illicit drug. In animals, high-dose administration of MDMA produces deficits in serotonin (5-HT) neurons (e.g., depletion of forebrain 5-HT) that have been interpreted as neurotoxicity. Whether such 5-HT deficits reflect neuronal damage is a matter of ongoing debate. OBJECTIVE: The present paper reviews four specific issues related to the hypothesis of MDMA neurotoxicity in rats: (1) the effects of MDMA on monoamine neurons, (2) the use of “interspecies scaling” to adjust MDMA doses across species, (3) the effects of MDMA on established markers of neuronal damage, and (4) functional impairments associated with MDMA-induced 5-HT depletions. RESULTS: MDMA is a substrate for monoamine transporters, and stimulated release of 5-HT, NE, and DA mediates effects of the drug. MDMA produces neurochemical, endocrine, and behavioral actions in rats and humans at equivalent doses (e.g., 1–2 mg/kg), suggesting that there is no reason to adjust doses between these species. Typical doses of MDMA causing long-term 5-HT depletions in rats (e.g., 10–20 mg/kg) do not reliably increase markers of neurotoxic damage such as cell death, silver staining, or reactive gliosis. MDMA-induced 5-HT depletions are accompanied by a number of functional consequences including reductions in evoked 5-HT release and changes in hormone secretion. Perhaps more importantly, administration of MDMA to rats induces persistent anxiety-like behaviors in the absence of measurable 5-HT deficits. CONCLUSIONS: MDMA-induced 5-HT depletions are not necessarily synonymous with neurotoxic damage. However, doses of MDMA which do not cause long-term 5-HT depletions can have protracted effects on behavior, suggesting even moderate doses of the drug may pose risks

Complexations in illite-fulvic acid-Cu2+ systems

As part of an extended project to illustrate how :heavy metals are complexed by natural aquatic particles, we conducted various experiments to study the adsorption of fulvic acid (FA) at aqueous illite surfaces and the complexation of heavy metal copper(II) in illite-FA bi-complexant systems. By analyzing batch adsorption and potentiometric titration data, we found that (i) the adsorption of FA by illite decreases with increases in pH values and its pH adsorption edge resembles those of SiO2-FA and montmorillonite-FA systems described by other researchers, (ii) it is possible to effectively simulate the complexation of Cu2+ ions in illite-FA bi-complexant systems by taking it to be an additive complexation of two mono-complexant systems (FA-Cu2+ and illite-Cu2+) and (iii) FA can inhibit the retention of heavy metals at solid surfaces by forming soluble complexes with metal ions. The above results and conclusions are supported by FT-IR analysis of various illite-FA-Cu2+ systems. (C) 1998 Elsevier Science Ltd. All rights reserved