735 research outputs found

    Use of Hydration Inhibitors to Improve Bond Durability of Aluminum Adhesive Joints

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    An investigation is conducted of the mechanisms by which nitrilotris methylene phosphonic acid (NTMP) and related compounds are adsorbed onto oxidized aluminum surfaces to inhibit hydration and increase the durability of adhesive bonds formed with inhibitor-treated panels. P - O - Al bonds are identified as the basis of adsorption, and it is found that water initially adsorbed onto the etched aluminum surfaces is displaced by the NTMP. The hydration of the NTMP-treated surfaces occurs in three stages, namely the reverisble physisorption of water, the slow dissolution of NTMP followed by rapid hydration of the freshly exposed Al2O3 to AlOOH and further hydration of the surface to Al(OH)3. Five properties of an ideal inhibitor are identified

    Age Related Changes in Cerebrovascular Reactivity and Its Relationship to Global Brain Structure

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    ACKNOWLEDGMENTS This study was funded by Alzheimerā€™s Research UK (ARUK) and the Aberdeen Biomedical Imaging Centre, University of Aberdeen. GDW, ADM and CS are part of the SINASPE collaboration (Scottish Imaging Network - A Platform for Scientific Excellence www.SINAPSE.ac.uk). The authors thank Gordon Buchan, Baljit Jagpal, Nichola Crouch, Beverly Maclennan and Katrina Klaasen for their help with running the experiment and Dawn Younie and Teresa Morris for their help with recruitment and scheduling. We also thank the residents of Aberdeen and Aberdeenshire, and further afield, for their generous participation.Peer reviewedPublisher PD

    Sex differences in the association of photoperiod with hippocampal subfield volumes in older adults : A crosssectional study in the UK Biobank cohort

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    Ā© 2020 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.Peer reviewedPublisher PD

    Fuzzy approximate entropy analysis of resting state fMRI signal complexity across the adult life span

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    Acknowledgment The authors would like to acknowledge the work of the International Consortium for Brain Mapping (ICBM) fMRI community in creating the resting state database and making it publicly available within the framework of the 1000 Functional Connectomes project (https://www.nitrc.org/projects/fcon_1000/). M.O. Sokunbi was supported by an MRC grant G1100629.Peer reviewedPreprin

    Occurrence and population densities of yeast species in a fresh-water lake

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    Quantitative studies of yeasts present in surface and deep water samples from a fresh water body (Douglas Lake, Michigan) revealed 12 species ( Candida parapsilosis, C. pulcherrima, Cryptococcus albidus, Cr. diffluens, Cr. gastricus, Cr. laurentii, Rhodotorula glutinis, R. pilimanae, R. rubra, Trichosporon cutaneum, Debaryomyces sp., ā€œblack yeastsā€). In two regions of surface sampling the population densities averaged 39.6 and 5.5 cells per 100 ml respectively, whereas the average deep water count was 40.3 cells per 100 ml. Yeasts of the genus Rhodotorula predominated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41778/1/10482_2005_Article_BF02046074.pd

    Inter-individual Differences in fMRI Entropy Measurements in Old Age

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI linkWe investigated the association between individual differences in cognitive performance in old age and the approximate entropy (ApEn) measured from functional magnetic resonance imaging (fMRI) data acquired from 40 participants of the Aberdeen Birth Cohort 1936 (ABC1936), while undergoing a visual information processing task: inspection time (IT). Participants took a version of the Moray House Test (MHT) No. 12 at age 11, a valid measure of childhood intelligence. The same individuals completed a test of non-verbal reasoning (Ravenā€™s Standard Progressive Matrices [RPM]) aged about 68 years. The IT, MHT and RPM scores were used as indicators of cognitive performance. Our results show that higher regional signal entropy is associated with better cognitive performance. This finding was independent of ability in childhood but not independent of current cognitive ability. ApEn is used for the first time to identify a potential source of individual differences in cognitive ability using fMRI data

    Intramyocellular lipid saturation as a new metabolic biomarker

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    Background: Endurance trained athletic healthy volunteers (Athl-HV) and type 2 diabetes patients (T2D) have higher levels of lipids in their skele- tal myocytes compared to healthy controls. Despite apparently similar metabolic storage, they are at opposite ends of insulin sensitivity and cardio-metabolic risk. Purpose: We investigated if the degree of saturation of the IntraMyoCel- lular Lipids (IMCL) will differentiate Athl-HV from T2D; and explored if an exercise intervention will induce changes in the IMCL saturation. Methods: Male, age matched Athl-HV and T2D were enrolled (n=25/group). Athl-HV had ā‰„ 5 years endurance training, T2D were seden- tary. Subjects were studied at baseline and after an exercise intervention (4 week deconditioning in Athl-HV and supervised bike training at ā‰„ 65% of peakVO2, 5 hours/week x 8 weeks in T2D). All subjects underwent cardio-pulmonary exercise testing (CPET), blood sampling for insulin sen- sitivity (QUICKI*) and single voxel 1H-magnetic resonance spectroscopy (1H-MRS) of the right vastus lateralis. 1H-MRS was acquired on 3T Philips Achieva with a 16-channel coil, point-resolved spectroscopy, variable pulse power and optimized relaxation delay water suppression and analysed in LCModel. We derived fractional lipid mass (fLM) and fractions of saturated (fSL) and unsaturated (fUL) lipids. Data were analysed by t tests, shown as meanĀ±SEM, statistical significance p < 0.05. Results: CPET and insulin sensitivity are presented in Table 1. T2D had higher fLM in the skeletal muscle compared to Athl-HV, at base- line (p=0.003) and after the exercise intervention (p=0.009), Figure 1A. At baseline, T2D had a different phenotype with a lower fSL and higher fUL compared to Athl-HV (82Ā±3 vs 88Ā±1% and 18Ā±3 vs 12Ā±1%, p=0.02 for both). Whilst deconditioning did not attract any significant changes in either fSL or fUL in Athl-HV (88Ā±1 to 86Ā±1% and 12Ā±1 to 14Ā±1, p=0.2), in contrast, with exercise training T2D significantly increased fSL (82Ā±3 to 88Ā±1%) and decreased their fUL (18Ā±3 to 12Ā±1%) (both p=0.01). Figure 1B and 1C. Conclusion: We demonstrate for the first time, in vivo, significant differ- ences in the IMCL amount and saturation between Athl-HV and T2D. IMCL saturation was changed by exercise training in T2D to mirror the phenotype seen in Athl-HV uncovering a new, independent biomarker of improved cardio-metabolic health

    Associations of fecal microbial profiles with breast cancer and non-malignant breast disease in the Ghana Breast Health Study

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    The gut microbiota may play a role in breast cancer etiology by regulating hormonal, metabolic and immunologic pathways. We investigated associations of fecal bacteria with breast cancer and nonmalignant breast disease in a case-control study conducted in Ghana, a country with rising breast cancer incidence and mortality. To do this, we sequenced the V4 region of the 16S rRNA gene to characterize bacteria in fecal samples collected at the time of breast biopsy (N = 379 breast cancer cases, N = 102 nonmalignant breast disease cases, N = 414 population-based controls). We estimated associations of alpha diversity (observed amplicon sequence variants [ASVs], Shannon index, and Faith's phylogenetic diversity), beta diversity (Bray-Curtis and unweighted/weighted UniFrac distance), and the presence and relative abundance of select taxa with breast cancer and nonmalignant breast disease using multivariable unconditional polytomous logistic regression. All alpha diversity metrics were strongly, inversely associated with odds of breast cancer and for those in the highest relative to lowest tertile of observed ASVs, the odds ratio (95% confidence interval) was 0.21 (0.13-0.36; Ptrend &lt;ā€‰.001). Alpha diversity associations were similar for nonmalignant breast disease and breast cancer grade/molecular subtype. All beta diversity distance matrices and multiple taxa with possible estrogen-conjugating and immune-related functions were strongly associated with breast cancer (all Psā€‰&lt;ā€‰.001). There were no statistically significant differences between breast cancer and nonmalignant breast disease cases in any microbiota metric. In conclusion, fecal bacterial characteristics were strongly and similarly associated with breast cancer and nonmalignant breast disease. Our findings provide novel insight into potential microbially-mediated mechanisms of breast disease
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