17 research outputs found
The Contribution of the Cerebellum to Cognition in Spinocerebellar Ataxia Type 6
This study sought evidence for a specific cerebellar contribution to cognition by characterising the cognitive phenotype of Spinocerebellar Ataxia Type 6 (SCA-6); an autosomal dominant genetic disease which causes a highly specific late-onset cerebellar degeneration. A comprehensive neuropsychological assessment was administered to 27 patients with genetically confirmed SCA-6. General intellectual ability, memory and executive function were examined using internationally standardised tests (Wechsler Adult Intelligence Scale-III, Wechsler Memory Scale-III, Delis and Kaplan Executive Function System, Brixton Spatial Anticipation test). The patient group showed no evidence of intellectual or memory decline. However, tests of executive function involving skills of cognitive flexibility, inhibition of response and verbal reasoning and abstraction demonstrated significant impairment at the group level with large effect sizes. The results demonstrate an executive deficit due to SCA-6 that can be conceptualised as parallel to the motor difficulties suffered by these patients: the data support a role for the cerebellum in the regulation and coordination of cognitive, as well as motor processes that is relevant to individual performance
Versatile routes to selenoether functionalised tertiary phosphines
New selenoether functionalised tertiary phosphines, based on
aryl (2a, 2b) or alkyl (4) backbones, have been synthesised
and characterised. P,Se-chelation has been achieved upon
complexation to square-planar PtII (3a) or PdII (3b) metal
centres. For 3a and 3b, weak non-covalent Mâ—Š â—Š â—Š Se contacts
were established using single crystal X-ray crystallography
Sulfimidation of thioether groups—a versatile method for modifying and linking thia/oxa crowns
Reaction of the mixed thioether/ether crowns [9]aneO2S 1, [12]aneO3S 2 and [18]aneO4S2 3 with one mol. equivalent of the aminating agent MSH (o-mesitylsulfonylhydroxylamine) in Et2O results in the formation of the mono-sulfimidated systems {[9]aneO2(SNH2)}+ 1a, {[12]aneO3(SNH2)}+ 2a and {[18]aneO4S(SNH2)}+ 3a, while using two mol. equivalents of MSH with 3 gives the disulfimidium cation {[18]aneO4(SNH2)2}2+ 3b. All of these species have been isolated in good yields as the [mesSO3]- (mes = 2,4,6-Me3C6H2) salts and can be readily converted to the [BPh4]- salts by metathesis with Na[BPh4]. Treatment of 1a or 2a with lithium diisopropylamide (LDA) and N-bromosuccinimide (NBS) at -78 °C, followed by addition of a further equivalent of the parent thia/oxa crown, gives monocationic N-bridged sulfimide bicyclic compounds ( 4 and 5 respectively), in which the crowns are linked by the sulfimidic nitrogen. Reaction of 3a with LDA and NBS leads to formation of the {([18]aneO4S2)N}+ cation 6 which exhibits an intramolecular S–N–S bridge. Crystallographic studies on representative examples of each compound type are described, together with their spectroscopic properties
Preparation of the first complexes of bidentate sulfimides; the X-ray crystal structures of [PdBr2{14(PhS{NH})(2)C6H4}](2)[PdC12{12-(PhS{NH})(PhSC6H4}] and trans- [PdC12{12-PhS{NH})(PhS)C6H4}PPh3]
The synthesis, full characterisation and utilisation of template-free silica sodalite, a novel polymorph of silica
Empty glass: Subjecting ethylene glycol silica sodalite to heat (680 °C) under a nitrogen atmosphere (i) successfully removes the templating agent to give cubic silica sodalite, which, upon consequent heating under an oxygen atmosphere (ii), transforms into a rhombohedral form of the empty sodalite, in effect a novel polymorph of silica
The first use of the free selenimide Ph2SeNH as a synthon; the synthesis and X-ray crystal structure of [Ph2SeNSePh2][BPh4]
Reaction of o-mesitylsulfonylhydroxylamine (MSH) with Ph2Se results in the [Ph2SeNH2]+ cation; low temperature deprotonation (LDA), bromination (NBS) and then treatment with Ph2Se–Na[BPh4] generates [Ph2SeNSePh2][BPh4], via the selenimides Ph2SeNH and Ph2SeNBr
Sulfimidation: a new and versatile strategy for the post ring-closure derivatisation of mixed thia/oxa crowns
Reaction of [18]aneO5S with the aminating agent MSH results in the {[18]aneO5SNH2}+ cation which may be converted through to the linked crown system [({[18]aneO5S}2N)]+via deprotonation, bromination and reaction with the parent crown; significantly, despite their positive charge, both systems can coordinate sodium cations to the ether linkages