(4aS,5R,7R,8S,8aR)-8-(1,3-Dioxolan-2-yl)-7,8-dimethyl-5-(1-methyl­ethen­yl)perhydro­naphthalen-2-one

In the chiral title compound, C18H28O3, the two six-membered rings of the perhydronaphthalenone adopt a rigid chair–chair conformation and the five-membered dioxolanyl ring adopts an envelope conformation. The crystal structure is stabilized only by weak inter­actions

Autism and Schizophrenia in high functioning adults: Behavioral differences and overlap

Several recent studies have demonstrated a genetical overlap between autism and schizophrenia. However, at a behavioral level it remains unclear which features can validly distinguish adults with autism from an adult schizophrenia group. To this end, the present study compared 21 individuals with the autistic disorder and 21 individuals with schizophrenia in self-reported features of autism and schizophrenia, as measured by the Autism-Spectrum Quotient (AQ) and the Schizotypal Personality Questionnaire(SPQ). The schizophrenia group was more likely to report positive symptoms and the adults with autism were more likely to report impairments in social skill. Overlap was found between the two groups in negative symptoms, disorganization, attention to detail and imagination. Thus, when discriminating between the two disorders, especially social skill and the presence of positive symptoms are relevant, whereas the presence of negative symptoms is not indicative

High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN2 and BaSiN2

We investigate the high-pressure phase diagram of SrSiN2 and BaSiN2 with density-functional calculation. Searching a manifold of possible candidate structures, we propose new structural modifications of SrSiN2 and BaSiN2 attainable in high-pressure experiments. The monoclinic ground state of SrSiN2 transforms at 3 GPa into an orthorhombic BaSiN2 type. At 14 GPa a CaSiN2-type structure becomes the most stable configuration of SrSiN2. A hitherto unknown Pbcm modification is adopted at 85 GPa and, finally, at 131 GPa a LiFeO2-type structure. The higher homologue BaSiN2 transforms to a CaSiN2 type at 41 GPa and further to a Pbcm modification at 105 GPa. Both systems follow the pressure-coordination rule: the coordination environment of Si increases from tetrahedral through trigonal bipyramidal to octahedral. Some high-pressure phases are related in structure through simple group–subgroup mechanisms, indicating displacive phase transformations with low activation barriers

14-Bromo-12-chloro-2,16-dioxapentacyclohenicosa-3(8),10,12,14-tetraene-7,20-dione

In the title compound, C19H16BrClO4, both the fused xanthene rings and one of the cyclohexane rings adopt envelope conformations, while the other cyclohexane ring is in a chair conformation. In the crystal, molecules are linked by C-H...O hydrogen bonds, forming infinite chains running along [10-1] incorporating R22(16) ring motifs. In addition, C-H...[pi] interactions and weak [pi]-[pi] stacking interactions [centroid-centroid distance = 3.768 (3) Å] help to consolidate the packing

Ureum als instrument om eiwitvoeding te sturen nog niet betrouwbaar: Kengetal ureumgehalte beter benutten

Wat kunnen melkveehouders met het ureumgehalte in melk? Het kengetal zegt iets over de stikstofbenutting, maar is als instrument om de eiwitvoeding van melkkoeien te sturen nu nog onvoldoende betrouwbaar. Wageningse onderzoekers pogen daar verbetering in te brenge

(S)-6-Methyl-∊-caprolactone

The chiral title compound, C7H12O2, a lactone derivative, features a seven-membered ring that adopts a chair conformation. The crystal structure is stabilized by weak C—H⋯O inter­actions occurring in the (100) plane. The absolute configuration was assigned on the basis of the enantioselective synthesis