709 research outputs found
A Chiral Sulfoxide-Based CâH Acid
We report the design and synthesis of a strong, chiral, enantiopure sulfoxide-based CâH acid. Single crystal X-ray analysis confirms the proposed structure and its absolute configuration. The new motif shows a high acidity and activity in BrĂžnsted and Lewis acid catalyzed transformations. So far,only little to no enantioselectivities were achieved
The role of mental disorders in the risk and speed of transition to alcohol use disorders among community youth
Background Among adolescents and young adults with DSM-IV alcohol use disorders (AUDs), there are inter-individual differences in the speed of transition from initial alcohol use (AU) to AUD. AUDs are highly co-morbid with other mental disorders. The factors associated with rapid transition from first AU to AUD remain unknown and the role of mental disorders in rapid transitions is unclear. Given this background we examined (1) whether prior anxiety, mood, externalizing and non-alcohol substance use disorders are related to the risk and speed of transition from first AU to DSM-IV alcohol abuse (AA) and alcohol dependence (AD) and (2) whether early age of onset of prior mental disorders (PMDs) is a promoter of rapid transition. Method A total of 3021 community subjects (97.7% lifetime AU) aged 14-24 years at baseline were followed up prospectively for up to 10 years. AU and mental disorders were assessed with the DSM-IV/M-CIDI. Results Among subjects with lifetime AU, several PMDs, such as specific phobia, bipolar disorder and nicotine dependence, were associated with an increased risk of AUD independent of externalizing disorders. Associations of PMDs with the speed of transition to AUDs were mostly weak and inconsistent. Only social phobia and externalizing disorders were associated with faster transitions to AD even after adjustment for other PMDs. Earlier age of onset of PMD was not associated with rapid transition. Conclusions Mental disorders are associated with the risk of AUD. With the possible exception of social phobia and externalizing disorders, they do not promote rapid transition, even if they occur particularly early. Future research needs to identify factors relevant to rapid transition to AU
1,1,3,3-Tetratriflylpropene (TTP): A Strong, Allylic CâH Acid for BrĂžnsted and Lewis Acid Catalysis
Tetratrifylpropene (TTP) has been developed as a highly acidic, allylic CâH acid for BrĂžnsted and Lewis acid catalysis. It can readily be obtained in two steps and consistently shows exceptional catalytic activities for Mukaiyama aldol, HosomiâSakurai, and FriedelâCrafts acylation reactions. X-ray analyses of TTP and its salts confirm its designed, allylic structure, in which the negative charge is delocalized over four triflyl groups. NMR experiments, acidity measurements, and theoretical investigations provide further insights to rationalize the remarkable reactivity of TTP
Experimental study of the impact of ion orbit losses on the edge radial electric field at the ASDEX Upgrade tokamak
Spanish Ministry of Science, Innovation and Universities (grant FPU17/06273)EUROfusion Consortium 63305
Pressure dependence of diffusion in simple glasses and supercooled liquids
Using molecular dynamics simulation, we have calculated the pressure
dependence of the diffusion constant in a binary Lennard-Jones Glass. We
observe four temperature regimes. The apparent activation volume drops from
high values in the hot liquid to a plateau value. Near the critical temperature
of the mode coupling theory it rises steeply, but in the glassy state we find
again small values, similar to the ones in the liquid. The peak of the
activation volume at the critical temperature is in agreement with the
prediction of mode coupling theory
Danger and loss events and the incidence of anxiety and depressive disorders: a prospective-longitudinal community study of adolescents and young adults
Background There are inconclusive findings regarding whether danger and loss events differentially predict the onset of anxiety and depression. Method A community sample of adolescents and young adults (n=2304, age 14-24 years at baseline) was prospectively followed up in up to four assessments over 10 years. Incident anxiety and depressive disorders were assessed at each wave using the DSM-IV/M-CIDI. Life events (including danger, loss and respectively mixed events) were assessed at baseline using the Munich Event List (MEL). Logistic regressions were used to reveal associations between event types at baseline and incident disorders at follow-up. Results Loss events merely predicted incident âpure' depression [odds ratio (OR) 2.4 per standard deviation, 95% confidence interval (CI) 1.5-3.9, p<0.001] whereas danger events predicted incident âpure' anxiety (OR 2.3, 95% CI 1.1-4.6, p=0.023) and âpure' depression (OR 2.5, 95% CI 1.7-3.5, p<0.001). Mixed events predicted incident âpure' anxiety (OR 2.9, 95% CI 1.5-5.7, p=0.002), âpure' depression (OR 2.4, 95% CI 1.6-3.4, p<0.001) and their co-morbidity (OR 3.6, 95% CI 1.8-7.0, p<0.001). Conclusions Our results provide further evidence for differential effects of danger, loss and respectively mixed events on incident anxiety, depression and their co-morbidity. Since most loss events referred to death/separation from significant others, particularly interpersonal loss appears to be highly specific in predicting depressio
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