γ-valerolactone (GVL) is a C5-cyclic ester that can be produced from biomass providing a potentially renewable fuel for transportation and feedstock for the chemical industry. Experiments were performed with fossil diesel (D), D + biodiesel (BD) and D + BD + GVL blends. A four-cylinder, turbocharged direct injection diesel engine was used for the tests. The engine was coupled to a dynamometer to vary the load. CO, NO x , THC and smoke emissions were measured by using a multi-channel gas analyzer. Combustion characteristics were assessed by in-cylinder pressure data with respect to crank angle and the derived heat release rates. Compared with D, and D + BD blends, addition of GVL had relatively little effect on engine performance and NO x emission, but reduced the exhaust concentration of CO, unburned fuel and smoke significantly. The smoke reduction is particularly notable in view of the very recent suggestion that black carbon is the second most important greenhouse gas in the atmosphere next to carbon dioxide. No diesel engine study with GVL has been reported so far.

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When two stimuli are associated and treated as equivalent, generalization occurs between them (acquired equivalence). The feedback-guided learning of associations is related to the basal ganglia, whereas the medial temporal lobe participates in acquired equivalence learning. In this study, we investigated feedback-guided associative learning and acquired equivalence in deficit and nondeficit schizophrenia. Results revealed that acquired equivalence learning was similarly impaired in deficit and nondeficit patients, whereas feedback-guided associative learning was impaired only in deficit patients. Associative learning and acquired equivalence were not related to frontal lobe tests. These results suggest that the enduring negative symptoms of deficit patients may be related to decreased response to cognitive feedback and deficient basal ganglia functioning.

The synthesis of all the possible isomers of the eburnameninevincamine type alkaloids l b , 2a*, 3a and derivatives 4, 8, 9, 10 is described. Structures were determined by 'H-and 13C-NMR spectroscopy including special techniques such as DR, DEPT, DNOE, and 2D-HSC. In contrast to the known cerebrovascular effects of cis-(3S,lGS) compounds, trans-(3S,lGR) derivatives show a significant peripheral vasodilator effect.

Pulsed laser photolysis (PLP) at λ=248 and 308 nm coupled with gas-chromatographic analysis is applied to determine the photodissociation quantum yield (QY) of methyl ethyl ketone (MEK). Temperature dependent UV absorption cross-sections [σ(MEK)(λ,T)] are also determined. At 308 nm, the QY decreases with decreasing temperature (T=323-233 K) and with increasing pressure (P=67-998 mbar synthetic air). Stern-Volmer (SV) analysis of the T and P dependent QYs provides the experimental estimate of E(S1)=398±9 kJ mol(-1) (=300±6 nm) for the barrier of the first excited singlet state (S(1)). The QY at 248 nm is close to unity and independent of pressure (T=298 K). Theoretical reaction pathways are examined systematically on the basis of CASPT2/6-31+G* calculations. Among three possible pathways, a S(1)/S(0)-diradical mechanism, which involves H atom transfer on the S(1) surface, followed by a nonadiabatic transition at a diradical isomer of MEK, explains the experimental data very well. Therefore, this unusual mechanism, which is not seen in any smaller carbonyl compounds, is proposed as an important pathway for the MEK dissociation. Our study supports the view that both the absorption cross-sections and the QYs of carbonyls have significant temperature dependences that should be taken into account for accurate modelling of atmospheric chemistry.