Abiotic synthesis of amino acids in the recesses of the oceanic lithosphere.

Abiotic hydrocarbons and carboxylic acids are known to be formed on Earth, notably during the hydrothermal alteration of mantle rocks. Although the abiotic formation of amino acids has been predicted both from experimental studies and thermodynamic calculations, its occurrence has not been demonstrated in terrestrial settings. Here, using a multimodal approach that combines high-resolution imaging techniques, we obtain evidence for the occurrence of aromatic amino acids formed abiotically and subsequently preserved at depth beneath the Atlantis Massif (Mid-Atlantic Ridge).

Motivational Sensitivities Linked to Impulsive Motor Errors in Parkinson's Disease.

Objectives: We investigated how broad motivational tendencies are related to the expression and suppression of action impulses in Parkinson's disease (PD).

Methods: Sixty-nine participants with PD completed a Simon response conflict task and Behavioral Inhibition System (BIS) and Behavioral Activation System (BAS) scales based on Gray's (1987) reinforcement sensitivity theory. Analyses determined relationships between BIS, BAS, and the susceptibility to making impulsive action errors and the proficiency of inhibiting interference from action impulses.

[Molecular diagnosis of fragile X syndrome].

Background: The fragile X syndrome was the most frequent etiology of hereditary mental retardation but the clinical diagnosis is not easy and the individual clinical symptoms were not specific so the confirmation will be made par molecular study of the gene of the fragile X syndrome. The aim of our study is to realise the molecular diagnosis of the fragile X syndrome in 200 Tunisian boys with mental retardation. Our results shows that the frequency of the fragile X syndrome is 7,6%.

Hydrothermal stability of adenine under controlled fugacities of N2, CO2 and H2.

An experimental study has been carried out on the stability of adenine (one of the five nucleic acid bases) under hydrothermal conditions. The experiments were performed in sealed autoclaves at 300 degrees C under fugacities of CO(2), N(2) and H(2) supposedly representative of those in marine hydrothermal systems on the early Earth. The composition of the gas phase was obtained from the degradation of oxalic acid, sodium nitrite and ammonium chloride, and the oxidation of metallic iron.