MIRIAD--Public release of a multiple time point Alzheimer's MR imaging dataset

The Minimal Interval Resonance Imaging in Alzheimer's Disease (MIRIAD) dataset is a series of longitudinal volumetric T1 MRI scans of 46 mild-moderate Alzheimer's subjects and 23 controls. It consists of 708 scans conducted by the same radiographer with the same scanner and sequences at intervals of 2, 6, 14, 26, 38 and 52 weeks, 18 and 24 months from baseline, with accompanying information on gender, age and Mini Mental State Examination (MMSE) scores. Details of the cohort and imaging results have been described in peer-reviewed publications, and the data are here made publicly available as a common resource for researchers to develop, validate and compare techniques, particularly for measurement of longitudinal volume change in serially acquired MR

Profiles of white matter tract pathology in frontotemporal dementia.

Despite considerable interest in improving clinical and neurobiological characterisation of frontotemporal dementia and in defining the role of brain network disintegration in its pathogenesis, information about white matter pathway alterations in frontotemporal dementia remains limited. Here we investigated white matter tract damage using an unbiased, template-based diffusion tensor imaging (DTI) protocol in a cohort of 27 patients with the behavioral variant of frontotemporal dementia (bvFTD) representing both major genetic and sporadic forms, in relation both to healthy individuals and to patients with Alzheimer's disease. Widespread white matter tract pathology was identified in the bvFTD group compared with both healthy controls and Alzheimer's disease group, with prominent involvement of uncinate fasciculus, cingulum bundle and corpus callosum. Relatively discrete and distinctive white matter profiles were associated with genetic subgroups of bvFTD associated with MAPT and C9ORF72 mutations. Comparing diffusivity metrics, optimal overall separation of the bvFTD group from the healthy control group was signalled using radial diffusivity, whereas optimal overall separation of the bvFTD group from the Alzheimer's disease group was signalled using fractional anisotropy. Comparing white matter changes with regional grey matter atrophy (delineated using voxel based morphometry) in the bvFTD cohort revealed co-localisation between modalities particularly in the anterior temporal lobe, however white matter changes extended widely beyond the zones of grey matter atrophy. Our findings demonstrate a distributed signature of white matter alterations that is likely to be core to the pathophysiology of bvFTD and further suggest that this signature is modulated by underlying molecular pathologies. Hum Brain Mapp, 2014. © 2014 Wiley Periodicals, Inc

Belowground DNA-based techniques: untangling the network of plant root interactions

Contains fulltext : 91591.pdf (publisher's version ) (Closed access)7 p

Patterns of atrophy in pathologically confirmed dementias: a voxelwise analysis

$\textbf{OBJECTIVE}$: Imaging is recommended to support the clinical diagnoses of dementias, yet imaging research studies rarely have pathological confirmation of disease. This study aims to characterise patterns of brain volume loss in six primary pathologies compared with controls and to each other. $\textbf{METHODS}$: One hundred and eighty-six patients with a clinical diagnosis of dementia and histopathological confirmation of underlying pathology, and 73 healthy controls were included in this study. Voxel-based morphometry, based on ante-mortem T1-weighted MRI, was used to identify cross-sectional group differences in brain volume. $\textbf{RESULTS}$: Early-onset and late-onset Alzheimer's disease exhibited different patterns of grey matter volume loss, with more extensive temporoparietal involvement in the early-onset group, and more focal medial temporal lobe loss in the late-onset group. The Presenilin-1 group had similar parietal involvement to the early-onset group with localised volume loss in the thalamus, medial temporal lobe and temporal neocortex. Lewy body pathology was associated with less extensive volume loss than the other pathologies, although precentral/postcentral gyri volume was reduced in comparison with other pathological groups. Tau and TDP43A pathologies demonstrated similar patterns of frontotemporal volume loss, although less extensive on the right in the 4-repeat-tau group, with greater parietal involvement in the TDP43A group. The TDP43C group demonstrated greater left anterior-temporal involvement. $\textbf{CONCLUSIONS}$: Pathologically distinct dementias exhibit characteristic patterns of regional volume loss compared with controls and other dementias. Voxelwise differences identified in these cohorts highlight imaging signatures that may aid in the differentiation of dementia subtypes during life. The results of this study are available for further examination via NeuroVault (http://neurovault.org/collections/ADHMHOPN/).The Dementia Research Centre is an Alzheimer’s Research UK coordinating centre. The authors acknowledge the support of Alzheimer’s Research UK (grant number ART-NCG2010B-2), the Medical Research Council (grant number MR/J014257/2), the NIHR Queen Square Dementia Biomedical Research Unit, UCL/H Biomedical Research Centre, the Leonard Wolfson Experimental Neurology Centre, the NIHR Newcastle Biomedical Research Unit in Lewy body dementia and the NIHR Cambridge Biomedical Research Unit in Dementia. LH is supported by funding from Alzheimer’s Research UK and a UCL Impact Studentship. NCF and JTOB hold NIHR Senior Investigator Awards. JMS acknowledges the support of the NIHR Queen Square Dementia BRU, the NIHR UCL/H Biomedical Research Centre, Wolfson Foundation, EPSRC (EP/J020990/1), MRC (CSUB19166), ARUK (ARUK-Network 2012–6-ICE; ARUK-PG2014-1946) and European Commission (H2020-PHC-2014-2015-666992)

Childhood socioeconomic position and objectively measured physical capability levels in adulthood: a systematic review and meta-analysis

<p><b>Background:</b> Grip strength, walking speed, chair rising and standing balance time are objective measures of physical capability that characterise current health and predict survival in older populations. Socioeconomic position (SEP) in childhood may influence the peak level of physical capability achieved in early adulthood, thereby affecting levels in later adulthood. We have undertaken a systematic review with meta-analyses to test the hypothesis that adverse childhood SEP is associated with lower levels of objectively measured physical capability in adulthood.</p> <p><b>Methods and Findings:</b> Relevant studies published by May 2010 were identified through literature searches using EMBASE and MEDLINE. Unpublished results were obtained from study investigators. Results were provided by all study investigators in a standard format and pooled using random-effects meta-analyses. 19 studies were included in the review. Total sample sizes in meta-analyses ranged from N = 17,215 for chair rise time to N = 1,061,855 for grip strength. Although heterogeneity was detected, there was consistent evidence in age adjusted models that lower childhood SEP was associated with modest reductions in physical capability levels in adulthood: comparing the lowest with the highest childhood SEP there was a reduction in grip strength of 0.13 standard deviations (95% CI: 0.06, 0.21), a reduction in mean walking speed of 0.07 m/s (0.05, 0.10), an increase in mean chair rise time of 6% (4%, 8%) and an odds ratio of an inability to balance for 5s of 1.26 (1.02, 1.55). Adjustment for the potential mediating factors, adult SEP and body size attenuated associations greatly. However, despite this attenuation, for walking speed and chair rise time, there was still evidence of moderate associations.</p> <p><b>Conclusions:</b> Policies targeting socioeconomic inequalities in childhood may have additional benefits in promoting the maintenance of independence in later life.</p&gt

Mid-Pleistocene climate transition drives net mass loss from rapidly uplifting St. Elias Mountains, Alaska

Erosion, sediment production and routing on a tectonically active continental margin reflect both tectonic and climatic processes; partitioning the relative importance of these processes remains controversial. Gulf of Alaska contains a preserved sedimentary record of Yakutat Terrane collision with North America. Because tectonic convergence in the coastal St. Elias orogen has been roughly constant for 6 Myr, variations in its eroded sediments preserved in the offshore Surveyor Fan constrain a budget of tectonic material influx, erosion, and sediment output. Seismically imaged sediment volumes calibrated with chronologies derived from Integrated Ocean Drilling Program boreholes shows that erosion accelerated in response to Northern Hemisphere glacial intensification (~2.7 Ma) and that the 900-km long Surveyor Channel inception appears to correlate with this event. However, tectonic influx exceeded integrated sediment efflux over the interval 2.8-1.2 Ma. Volumetric erosion accelerated following the onset of quasi-periodic (~100-kyr) glacial cycles in the mid-Pleistocene climate transition (1.2-0.7 Ma). Since then erosion and transport of material out of the orogen has outpaced tectonic influx by 50-80%. Such a rapid net mass loss explains apparent increases in exhumation rates inferred onshore from exposure dates and mapped out-of-sequence fault patterns. The 1.2 Myr mass budget imbalance must relax back toward equilibrium in balance with tectonic influx over the time scale of orogenic wedge response (Myrs). The St. Elias Range provides a key example of how active orogenic systems respond to transient mass fluxes, and the possible influence of climate driven erosive processes that diverge from equilibrium on the million-year scale

The Expanding Fireball of Nova Delphini 2013

A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting from one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 +/- 0.59 kpc from the Sun.Comment: Published in Nature. 32 pages. Final version available at http://www.nature.com/nature/journal/v515/n7526/full/nature13834.htm

Diffusion of an e-learning programme among Danish General Practitioners: A nation-wide prospective survey

<p>Abstract</p> <p>Background</p> <p>We were unable to identify studies that have considered the diffusion of an e-learning programme among a large population of general practitioners. The aim of this study was to investigate the uptake of an e-learning programme introduced to General Practitioners as part of a nation-wide disseminated dementia guideline.</p> <p>Methods</p> <p>A prospective study among all 3632 Danish GPs. The GPs were followed from the launching of the e-learning programme in November 2006 and 6 months forward. Main outcome measures: Use of the e-learning programme. A logistic regression model (GEE) was used to identify predictors for use of the e-learning programme.</p> <p>Results</p> <p>In the study period, a total of 192 different GPs (5.3%) were identified as users, and 17% (32) had at least one re-logon. Among responders at first login most have learnt about the e-learning programme from written material (41%) or from the internet (44%). A total of 94% of the users described their ability of conducting a diagnostic evaluation as good or excellent. Most of the respondents used the e-learning programme due to general interest (90%). Predictors for using the e-learning programme were Males (OR = 1.4, 95% CI 1.1; 2.0) and members of Danish College of General Practice (OR = 2.2, 95% CI 1.5; 3.1), whereas age, experience and working place did not seem to be influential.</p> <p>Conclusion</p> <p>Only few Danish GPs used the e-learning programme in the first 6 months after the launching. Those using it were more often males and members of Danish College of General Practice. Based on this study we conclude, that an active implementation is needed, also when considering electronic formats of CME like e-learning.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier: NCT00392483.</p

Mycoplasma hominis brain abscess following uterus curettage: a case report

<p>Abstract</p> <p>Introduction</p> <p><it>Mycoplasma hominis </it>is mostly known for causing urogenital infections. However, it has rarely been described as an agent of brain abscess.</p> <p>Case presentation</p> <p>We describe a case of <it>M. hominis </it>brain abscess in a 41-year-old Caucasian woman following uterus curettage. The diagnosis was obtained by 16S rDNA amplification, cloning and sequencing from the abscess pus, and confirmed by a specifically designed real-time polymerase chain reaction assay.</p> <p>Conclusions</p> <p>Findings from our patient's case suggest that <it>M. hominis </it>should be considered as a potential agent of brain abscess, especially following uterine manipulation.</p

Stationary Black Holes: Uniqueness and Beyond

The spectrum of known black-hole solutions to the stationary Einstein equations has been steadily increasing, sometimes in unexpected ways. In particular, it has turned out that not all black-hole-equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro-vacuum black-hole spacetimes ceases to exist in self-gravitating non-linear field theories. This text aims to review some developments in the subject and to discuss them in light of the uniqueness theorem for the Einstein-Maxwell system.Comment: Major update of the original version by Markus Heusler from 1998. Piotr T. Chru\'sciel and Jo\~ao Lopes Costa succeeded to this review's authorship. Significantly restructured and updated all sections; changes are too numerous to be usefully described here. The number of references increased from 186 to 32