Proton (1H) magnetic resonance spectroscopy: absolute metabolite concentrations in normal aging human brain at 3Tesla

Session - Normal Aging Brain: Computer 90 (Tuesday)OBJECTIVES: Absolute quantitation of metabolite levels of normal aging human brain has rarely been done. But using a 3T scanner, which provides better signal-to-noise ratio, spectrum with higher resolution can be obtained. MRS can explore aging at a molecular level but controversial findings had been reported in previous frontal lobe studies [1,2] In this study, we investigate in the relationship between regional concentrations of …published_or_final_versionThe 19th Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2011), Montreal, QC., 7-13 May 2011. In Proceedings of the 19th ISMRM, 2011, v. 19, p. 404

Relevance of short-range connectivity to brain compensation and cognitive efficiency in healthy and pathological ageing: a combined functional magnetic resonance imaging and tractography study on prospective memory

INTRODUCTION: Cognition and its efficiency are related to the activities of specific brain regions and their interactions. The brain function and structure are vulnerable to both healthy and pathological ageing, and these processes may underlie the impaired cognitive functions in daily life …published_or_final_versio

Structural MRI measures in Alzheimer's disease and effects of ethnicity

This journal suppl. contain abstracts of AAIC2013BACKGROUND: Alzheimer's disease (AD) affects populations worldwide, and there are increasing numbers of AD-focused international neuroimaging studies. For these global cohorts, ethnicity may be a confounding factor. Morphometric differences have been found between European and Japanese brains, though the implications for common AD neuroimaging biomarkers, such as hippocampal volume and cortical thickness, are unknown and should be investi …postprin

Declined frontal white matter integrity in Alzheimer’s disease: a diffusion tensor imaging study

INTRODUCTION: Previous studies on structural changes of Alzheimer’s disease (AD) have been focused on grey matter atrophy. There is a resurgence of interests on white matter integrity in this prominently increasing patient population. Diffusion tensor imaging (DTI) provides key information on the microstructural changes beyond macroscopic anatomical imaging by in-vivo tracing molecular diffusion in the brain, and the measured fractional anisotrophy (FA) value may represent axonal integrity of neuronal networks. Data of DTI from AD patients are limited, and the literature is controversial regarding whether the AD process has a greater impact on anterior versus posterior cerebral white matter. METHODS: Eighteen patients with mild AD and 16 age-matched healthy adults were recruited into the study. Demographic features of the two groups were comparable. Data of DTI were collected using a Philips 3.0T MRI scanner. Scan parameters were as follows: B0=800 s/mm2, FOV=224*224*140 mm, resolution=1.75*1.75*2 mm, non-collinear 15 directions was acquired. 3D T1 anatomy was also collected. We processed DTI data with DTI toolbox, and anatomical T1 data with VBM5 toolbox in SPM. Voxel-by-voxel analysis was applied to compare the difference in FA value, and volume of white matter of the normalised brain between the elderly and AD groups. RESULTS: Voxel-based analysis showed no significant difference in white matter volume between the two groups, but FA value was reduced greatly in the left anterior cingulate (−10,37,−3), right anterior cingulate (12,0,28), and left medial frontal lobe (−18,32,−12). Minor reduction was found in other brain regions such as body of the corpus callosum, right midbrain (12,−12,−6), right posterior corpus callosum (8,−44,2), and bilateral, especially right temporal lobe (36,−8,−20), upon right hippocampus. Coordinates (x,y,z) were labelled according to Talairach atlas. CONCLUSION: DTI could be valid and more sensitive than traditional T1 anatomy in detecting microscopic white matter lesions. Our data showed a greater decrement in FA value over the anterior than posterior brain regions, and this decrement was not due to white matter atrophy. Our findings are in line with the retrogenesis hypothesis which predicts reversed demyelination during the process of AD, as the frontal lobe fibres are myelinated relatively late during brain development. These results also support previous findings of our behavioural study that frontal lobe abnormality might be the neural basis for cognitive deficit in AD patients.published_or_final_versionThe 15th Medical Research Conference; Department of Medicine, The University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16 suppl 1, p. 21, abstract no. 2

Graphene Photonics and Optoelectronics

The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential to be in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultra-wide-band tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light emitting devices, to touch screens, photodetectors and ultrafast lasers. Here we review the state of the art in this emerging field.Comment: Review Nature Photonics, in pres

Diversity Partitioning of Stony Corals Across Multiple Spatial Scales Around Zanzibar Island, Tanzania

The coral reefs of Zanzibar Island (Unguja, Tanzania) encompass a considerable proportion of the global coral-reef diversity and are representative of the western Indian Ocean region. Unfortunately, these reefs have been recently subjected to local and regional disturbances. The objectives of this study were to determine whether there are potentially non-random processes forcing the observed coral diversity patterns, and highlight where and at which spatial scales these processes might be most influential.A hierarchical (nested) sampling design was employed across three spatial scales, ranging from transects (<or=20 m), stations (<100 m), to sites (<1000 m), to examine coral diversity patterns. Two of the four sites, Chumbe and Mnemba, were located within Marine Protected Areas (MPAs), while the other two sites, Changuu and Bawe, were not protected. Additive partitioning of coral diversity was used to separate regional (total) diversity (gamma) into local alpha diversity and among-sample beta diversity components. Individual-based null models were used to identify deviations from random distribution across the three spatial scales. We found that Chumbe and Mnemba had similar diversity components to those predicted by the null models. However, the diversity at Changuu and Bawe was lower than expected at all three spatial scales tested. Consequently, the relative contribution of the among-site diversity component was significantly greater than expected. Applying partitioning analysis for each site separately revealed that the within-transect diversity component in Changuu was significantly lower than the null expectation.The non-random outcome of the partitioning analyses helped to identify the among-sites scale (i.e., 10's of kilometers) and the within-transects scale (i.e., a few meters; especially at Changuu) as spatial boundaries within which to examine the processes that may interact and disproportionately differentiate coral diversity. In light of coral community compositions and diversity patterns we strongly recommend that Bawe be declared a MPA

A case study of physical and social barriers to hygiene and child growth in remote Australian Aboriginal communities

Background\ud Despite Australia's wealth, poor growth is common among Aboriginal children living in remote communities. An important underlying factor for poor growth is the unhygienic state of the living environment in these communities. This study explores the physical and social barriers to achieving safe levels of hygiene for these children.\ud \ud Methods\ud A mixed qualitative and quantitative approach included a community level cross-sectional housing infrastructure survey, focus groups, case studies and key informant interviews in one community.\ud \ud Results\ud We found that a combination of crowding, non-functioning essential housing infrastructure and poor standards of personal and domestic hygiene underlie the high burden of infection experienced by children in this remote community.\ud \ud Conclusion\ud There is a need to address policy and the management of infrastructure, as well as key parenting and childcare practices that allow the high burden of infection among children to persist. The common characteristics of many remote Aboriginal communities in Australia suggest that these findings may be more widely applicable

Assessing cognitive insight in nonpsychiatric individuals and outpatients with schizophrenia in Taiwan: an investigation using the Beck Cognitive Insight Scale

<p>Abstract</p> <p>Background</p> <p>The Beck Cognitive Insight Scale (BCIS) was designed for the assessment of the cognitive processes involved in self-reflection and the ability to modify erroneous beliefs and misinterpretations. Studies investigating the factor structure of the BCIS have indicated a two-factor model in the psychotic population. The factor structure of the BCIS, however, has not received much consideration in the nonpsychiatric population. The present study examined the factor structure and validity of the BCIS and compared its scores between nonpsychiatric individuals and outpatients with psychosis.</p> <p>Method</p> <p>The Taiwanese version of the BCIS was administered to 507 nonpsychiatric individuals and 118 outpatients with schizophrenia. The psychometric properties of the BCIS were examined through the following analyses: exploratory and confirmatory factor analyses, reliability, correlation analyses, and discriminative validity.</p> <p>Results</p> <p>The BCIS showed adequate internal consistency and stability over time. Exploratory and confirmatory factor analyses on the 15-item measure indicated a two-factor solution that supported the two dimensions of the Taiwanese BCIS, which was also observed with the original BCIS. Following the construct validation, we obtained a composite index (self-reflectiveness minus self-certainty) of the Taiwanese BCIS that reflected cognitive insight. Consistent with previous studies, our results indicated that psychosis is associated with low self-reflectiveness and high self-certainty, which possibly reflect lower cognitive insight. Our results also showed that better cognitive insight is related to worse depression in patients with schizophrenia spectrum disorders, but not in nonpsychiatric individuals. The receiver operating characteristic (ROC) analyses revealed that the area under the curve (AUC) was 0.731. A composite index of 3 was a good limit, with a sensitivity of 87% and a specificity of 51%.</p> <p>Conclusion</p> <p>The BCIS proved to be useful for measuring cognitive insight in Taiwanese nonpsychiatric and psychotic populations.</p

Multi-Organ Expression Profiling Uncovers a Gene Module in Coronary Artery Disease Involving Transendothelial Migration of Leukocytes and LIM Domain Binding 2: The Stockholm Atherosclerosis Gene Expression (STAGE) Study

Environmental exposures filtered through the genetic make-up of each individual alter the transcriptional repertoire in organs central to metabolic homeostasis, thereby affecting arterial lipid accumulation, inflammation, and the development of coronary artery disease (CAD). The primary aim of the Stockholm Atherosclerosis Gene Expression (STAGE) study was to determine whether there are functionally associated genes (rather than individual genes) important for CAD development. To this end, two-way clustering was used on 278 transcriptional profiles of liver, skeletal muscle, and visceral fat (n = 66/tissue) and atherosclerotic and unaffected arterial wall (n = 40/tissue) isolated from CAD patients during coronary artery bypass surgery. The first step, across all mRNA signals (n = 15,042/12,621 RefSeqs/genes) in each tissue, resulted in a total of 60 tissue clusters (n = 3958 genes). In the second step (performed within tissue clusters), one atherosclerotic lesion (n = 49/48) and one visceral fat (n = 59) cluster segregated the patients into two groups that differed in the extent of coronary stenosis (P = 0.008 and P = 0.00015). The associations of these clusters with coronary atherosclerosis were validated by analyzing carotid atherosclerosis expression profiles. Remarkably, in one cluster (n = 55/54) relating to carotid stenosis (P = 0.04), 27 genes in the two clusters relating to coronary stenosis were confirmed (n = 16/17, P<10−27and−30). Genes in the transendothelial migration of leukocytes (TEML) pathway were overrepresented in all three clusters, referred to as the atherosclerosis module (A-module). In a second validation step, using three independent cohorts, the A-module was found to be genetically enriched with CAD risk by 1.8-fold (P<0.004). The transcription co-factor LIM domain binding 2 (LDB2) was identified as a potential high-hierarchy regulator of the A-module, a notion supported by subnetwork analysis, by cellular and lesion expression of LDB2, and by the expression of 13 TEML genes in Ldb2–deficient arterial wall. Thus, the A-module appears to be important for atherosclerosis development and, together with LDB2, merits further attention in CAD research