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- van Doorn, Ljcv, et al.
(författare)
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Improved Cerebrospinal Fluid-Based Discrimination between Alzheimer's Disease Patients and Controls after Correction for Ventricular Volumes
- 2017
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 56:2, s. 543-555
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Tidskriftsartikel (refereegranskat)abstract
- Cerebrospinal fluid (CSF) biomarkers may support the diagnosis of Alzheimer's disease (AD). We studied if the diagnostic power of AD CSF biomarker concentrations, i.e., A beta(42), total tau (t-tau), and phosphorylated tau (p-tau), is affected by differences in lateral ventricular volume (VV), using CSF biomarker data and magnetic resonance imaging (MRI) scans of 730 subjects, from 13 European Memory Clinics. We developed a Matlab-algorithm for standardized automated segmentation analysis of T1 weighted MRI scans in SPM8 for determining VV, and computed its ratio with total intracranial volume (TIV) as proxy for total CSF volume. The diagnostic power of CSF biomarkers (and their combination), either corrected for VV/TIV ratio or not, was determined by ROC analysis. CSF A beta(42) levels inversely correlated to VV/TIV in the whole study population (A beta(42): r = -0.28; p < 0.0001). For CSF t-tau and p-tau, this association only reached statistical significance in the combined MCI and AD group (t-tau: r = -0.15; p-tau: r = -0.13; both p < 0.01). Correction for differences in VV/TIV improved the differentiation of AD versus controls based on CSF A beta(42) alone (AUC: 0.75 versus 0.81) or in combination with t-tau (AUC: 0.81 versus 0.91). In conclusion, differences in VV may be an important confounder in interpreting CSF A beta(42) levels.
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- Benavidez, A. D., et al.
(författare)
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Environmental Transmission Electron Microscopy Study of the Origins of Anomalous Particle Size Distributions in Supported Metal Catalysts
- 2012
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 2:11, s. 2349-2356
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Tidskriftsartikel (refereegranskat)abstract
- In this Environmental Transmission Electron Microscopy (ETEM) study we examined the growth patterns' of uniform distributions of nanoparticles (NPs) using model catalysts. Pt/SiO2 was heated at 550 degrees C in 560 Pa of O-2 while Pd/carbon was heated in vacuum at 500 degrees C and in 300 Pa of 5%H-2 in Argon at temperatures up to 600 degrees C. Individual NPs of Pd were tracked to determine the operative sintering mechanisms. We found anomalous growth Of NPs occurred during the early stages of catalyst sintering wherein some particles started to grow significantly larger than the mean, resulting in a broadening of the particle size distribution (PSD). The abundance of the larger particles did not fit the log normal distribution. We can rule out sample nonuniformity as a cause for the growth of these large particles, since images were recorded prior to heat treatments. The anomalous growth of these particles may help explain PSDs in heterogeneous catalysts which often show particles that are significantly larger than the mean, resulting in a long tail to the right. It has been suggested previously that particle migration and coalescence could be the likely cause for such broad size distributions. We did not detect any random migration of the NPs leading to coalescence. A directed migration process was seen to occur at elevated temperatures for Pd/carbon under H-2. This study shows that anomalous growth of NPs can occur under conditions where Ostwald ripening is the primary sintering mechanism.
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- Kruse, N., et al.
(författare)
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Validation of a quantitative cerebrospinal fluid alpha-synuclein assay in a European-wide interlaboratory study
- 2015
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580. ; 36:9, s. 2587-2596
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Tidskriftsartikel (refereegranskat)abstract
- Decreased levels of alpha-synuclein (aSyn) in cerebrospinal fluid (CSF) in Parkinson's disease and related synucleinopathies have been reported, however, not consistently in all cross-sectional studies. To test the performance of one recently released human-specific enzyme-linked immunosorbent assay (ELISA) for the quantification of aSyn in CSF, we carried out a round robin trial with 18 participating laboratories trained in CSF ELISA analyses within the BIOMARKAPD project in the EU Joint Program -Neurodegenerative Disease Research. CSF samples (homogeneous aliquots from pools) and ELISA kits (one lot) were provided centrally and data reported back to one laboratory for data analysis. Our study showed that although factors such as preanalytical sample handling and lot-to-lot variability were minimized by our study design, we identified high variation in absolute values of CSF aSyn even when the same samples and same lots of assays were applied. We further demonstrate that although absolute concentrations differ between laboratories the quantitative results are comparable. With further standardization this assay may become an attractive tool for comparing aSyn measurements in diverse settings. Recommendations for further validation experiments and improvement of the interlaboratory results obtained are given. (C) 2015 Elsevier Inc. All rights reserved.
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- Travassos, M., et al.
(författare)
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Does Caffeine Consumption Modify Cerebrospinal Fluid Amyloid-beta Levels in Patients with Alzheimer's Disease?
- 2015
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 47:4, s. 1069-1078
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Tidskriftsartikel (refereegranskat)abstract
- Caffeine may be protective against Alzheimer's disease (AD) by modulating amyloid-beta (A beta) metabolic pathways. The present work aimed to study a possible association of caffeine consumption with the cerebrospinal fluid (CSF) biomarkers, particularly A beta. The study included 88 patients with AD or mild cognitive impairment. The consumption of caffeine and theobromine was evaluated using a validated food questionnaire. Quantification of caffeine and main active metabolites was performed with liquid chromatography coupled to tandem mass spectrometry. The levels of A beta(1-42), total tau, and phosphorylated tau in the CSF were determined using sandwich ELISA methods and other A beta species, A beta(X-38), A beta(X-40), and A beta(X-42), with the MSD A beta Triplex assay. The concentration of caffeine was 0.79 +/- 1.15 mu g/mL in the CSF and 1.20 +/- 1.88 mu g/mL in the plasma. No correlation was found between caffeine consumption and A beta(42) in the CSF. However, a significant positive correlation was found between the concentrations of theobromine, both in the CSF and in the plasma, with A beta(42) in the CSF. Theobromine in the CSF was positively correlated with the levels of other xanthines in the CSF, but not in the plasma, suggesting that it may be formed by central metabolic pathways. In conclusion, caffeine consumption does not modify the levels of CSF biomarkers, and does not require to be controlled for when measuring CSF biomarkers in a clinical setting. Since theobromine is associated with a favorable A beta profile in the CSF, the possibility that it might have a protective role in AD should be further investigated.
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- Buruk, Oguz'Oz', et al.
(författare)
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Children in 2077: Designing children's technologies in the age of transhumanism
- 2020
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Ingår i: Conference on Human Factors in Computing Systems - Proceedings. - New York, NY, USA : ACM.
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Konferensbidrag (refereegranskat)abstract
- What for and how will we design children's technologies in the transhumanism age, and what stance will we take as designers? This paper aims to answer this question with 13 fictional abstracts from sixteen authors of different countries, institutions and disciplines. Transhumanist thinking envisions enhancing human body and mind by blending human biology with technological augmentations. Fundamentally, it seeks to improve the human species, yet the impacts of such movement are unknown and the implications on children's lives and technologies were not explored deeply. In an age, where technologies such as under-skin chips or brain-machine interfaces can clearly be defined as transhumanist, our aim is to reveal probable pitfalls and benefits of those technologies on children's lives by using the power of design fiction. Thus, main contribution of this paper is to create diverse presentation of provocative research ideas that will foster the discussion on the transhumanist technologies impacting the lives of children in the future.
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