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Longitudinal studies of first episode of psychosis (FEP) patients are critical to understanding the dynamic clinical factors influencing functional outcomes; negative symptoms and verbal memory (VM) deficits are two such factors that remain a therapeutic challenge. This study uses white-gray matter contrast at the inner edge of the cortex, in addition to cortical thickness, to probe changes in microstructure and their relation with negative symptoms and possible intersections with verbal memory.
T1-weighted images and clinical data were collected longitudinally for patients (N = 88) over a two-year period. Cognitive data were also collected at baseline. Relationships between baseline VM (immediate/delayed recall) and rate of change in two negative symptom dimensions, amotivation and expressivity, were assessed at the behavioral level, as well as at the level of brain structure.
VM, particularly immediate recall, was significantly and positively associated with a steeper rate of expressivity symptom decline (r = 0.32, q = 0.012). Significant interaction effects between baseline delayed recall and change in expressivity were uncovered in somatomotor regions bilaterally for both white-gray matter contrast and cortical thickness. Furthermore, interaction effects between immediate recall and change in expressivity on cortical thickness rates were uncovered across higher-order regions of the language processing network.
This study shows common neural correlates of language-related brain areas underlying expressivity and VM in FEP, suggesting deficits in these domains may be more linked to speech production rather than general cognitive capacity. Together, white-gray matter contrast and cortical thickness may optimally inform clinical investigations aiming to capture peri-cortical microstructural changes.
The Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) cohort study of the Canadian Consortium on Neurodegeneration in Aging (CCNA) is a national initiative to catalyze research on dementia, set up to support the research agendas of CCNA teams. This cross-country longitudinal cohort of 2310 deeply phenotyped subjects with various forms of dementia and mild memory loss or concerns, along with cognitively intact elderly subjects, will test hypotheses generated by these teams.
The COMPASS-ND protocol, initial grant proposal for funding, fifth semi-annual CCNA Progress Report submitted to the Canadian Institutes of Health Research December 2017, and other documents supplemented by modifications made and lessons learned after implementation were used by the authors to create the description of the study provided here.
The CCNA COMPASS-ND cohort includes participants from across Canada with various cognitive conditions associated with or at risk of neurodegenerative diseases. They will undergo a wide range of experimental, clinical, imaging, and genetic investigation to specifically address the causes, diagnosis, treatment, and prevention of these conditions in the aging population. Data derived from clinical and cognitive assessments, biospecimens, brain imaging, genetics, and brain donations will be used to test hypotheses generated by CCNA research teams and other Canadian researchers. The study is the most comprehensive and ambitious Canadian study of dementia. Initial data posting occurred in 2018, with the full cohort to be accrued by 2020.
Availability of data from the COMPASS-ND study will provide a major stimulus for dementia research in Canada in the coming years.
The Flat Rocks locality in the Wonthaggi Formation (Strzelecki Group) of the Gippsland Basin, southeastern Australia, hosts fossils of a late Barremian vertebrate fauna that inhabited the ancient rift between Australia and Antarctica. Known from its dentary, Qantassaurus intrepidus Rich and Vickers-Rich, 1999 has been the only dinosaur named from this locality. However, the plethora of vertebrate fossils collected from Flat Rocks suggests that further dinosaurs await discovery. From this locality, we name a new small-bodied ornithopod, Galleonosaurus dorisae n. gen. n. sp. from craniodental remains. Five ornithopodan genera are now named from Victoria. Galleonosaurus dorisae n. gen. n. sp. is known from five maxillae, from which the first description of jaw growth in an Australian dinosaur is provided. The holotype of Galleonosaurus dorisae n. gen. n. sp. is the most complete dinosaur maxilla known from Victoria. Micro-CT imagery of the holotype reveals the complex internal anatomy of the neurovascular tract and antorbital fossa. We confirm that Q. intrepidus is uniquely characterized by a deep foreshortened dentary. Two dentaries originally referred to Q. intrepidus are reassigned to Q. ?intrepidus and a further maxilla is referred to cf. Atlascopcosaurus loadsi Rich and Rich, 1989. A further ornithopod dentary morphotype is identified, more elongate than those of Q. intrepidus and Q. ?intrepidus and with three more tooth positions. This dentary might pertain to Galleonosaurus dorisae n. gen. n. sp. Phylogenetic analysis recovered Cretaceous Victorian and Argentinian nonstyracosternan ornithopods within the exclusively Gondwanan clade Elasmaria. However, the large-bodied taxon Muttaburrasaurus langdoni Bartholomai and Molnar, 1981 is hypothesised as a basal iguanodontian with closer affinities to dryomorphans than to rhabdodontids.
There are multiple recent reports of an association between anxious/depressed (A/D) symptomatology and the rate of cerebral cortical thickness maturation in typically developing youths. We investigated the degree to which anxious/depressed symptoms are tied to age-related microstructural changes in cerebral fiber pathways. The participants were part of the NIH MRI Study of Normal Brain Development. Child Behavior Checklist A/D scores and diffusion imaging were available for 175 youths (84 males, 91 females; 241 magnetic resonance imagings) at up to three visits. The participants ranged from 5.7 to 18.4 years of age at the time of the scan. Alignment of fractional anisotropy data was implemented using FSL/Tract-Based Spatial Statistics, and linear mixed model regression was carried out using SPSS. Child Behavior Checklist A/D was associated with the rate of microstructural development in several white matter pathways, including the bilateral anterior thalamic radiation, bilateral inferior longitudinal fasciculus, left superior longitudinal fasciculus, and right cingulum. Across these pathways, greater age-related fractional anisotropy increases were observed at lower levels of A/D. The results suggest that subclinical A/D symptoms are associated with the rate of microstructural development within several white matter pathways that have been implicated in affect regulation, as well as mood and anxiety psychopathology.
The electrical activation of As implanted Si has been investigated on rapid thermal annealing timescales using sheet resistance, spreading resistance and Hall Effect techniques. For high dose implants (>1015 As cm-2) differential Hall Effect and spreading resistance profiles confirm the existence of a temperature dependent electrical solubility limit. However for low dose implants, annealing schedules chosen such that the electrical solubility limit is not exceeded reveal electrical deactivation which is not accounted for in the clustering theory. Hall Effect measurements performed as a function of temperature have enabled us to reveal directly electrically inactive As which is not observable at room temperature using standard electrical techniques. The results indicate that As atoms in Si introduce deep trapping levels within the bandgap which are responsible forremoving As from the conduction process at room temperature. This temperature activated process is characterized with an activation energy of 0.4eV.
A new family of materials that synergistically combine the attributes of both organic and inorganic properties for use in organic light emitting diodes (OLEDs) is presented. The hybrid materials are based on 3-D inorganic cores of octavinylsilsesquioxanes (OVS). The resultant materials have high Tg's (120–210°C), are formed from minimal step/high yield reactions and readily available starting reagents, are monodisperse (PDI<1.1), can be highly purified via common chroma-tographic techniques, and form defect-free amorphous films via spin-dip coating. For example TPD is known for its good hole injection/transport properties in OLED applications but suffers from a low Tg (65°C). TPD-OVS hybrid material has a Tg of 142°C while maintaining similar injection/transport properties to TPD. Photoluminescence analysis of the hybrid thin film reveals: 1) a 30 nm blue shift versus their dilute solution counterparts; and 2) 5 hour annealing cycles to within 10°C of their Tg show no indication of eximer formation (no red shift) that often causes reduced efficiencies in polymer LEDs.
Measuring recovery of function may mean testing
the same individual many times, a procedure that is inevitably
open to improvement due to learning on the specific tests
rather than recovery per se. This is particularly
likely to be an issue with measures of memory performance.
We therefore studied the performance of normal and brain-injured
people across 20 successive test sessions on measures of
orientation, simple reaction time, forward and backward
digit span, visual and verbal recognition, word list learning
and forgetting, and on three semantic memory measures,
namely, letter and category fluency and speed of semantic
processing. Differences in overall performances between
the two groups occurred for all tests other than orientation,
digit span forward, and simple reaction time, although
the tests differed in their degree of sensitivity. The
tests varied in the presence or absence of practice effects
and in the extent to which these differed between the two
groups. Data are presented that should allow investigators
to select measures that are likely to optimize sensitivity
while minimizing possible confounding due to practice effects.
(JINS, 2000, 6, 469–479.)