Comprehensive analysis of epigenetic clocks reveals associations between disproportionate biological ageing and hippocampal volume

The concept of age acceleration, the difference between biological age and chronological age, is of growing interest, particularly with respect to age-related disorders, such as Alzheimer’s Disease (AD). Whilst studies have reported associations with AD risk and related phenotypes, there remains a lack of consensus on these associations. Here we aimed to comprehensively investigate the relationship between five recognised measures of age acceleration, based on DNA methylation patterns (DNAm age), and cross-sectional and longitudinal cognition and AD-related neuroimaging phenotypes (volumetric MRI and Amyloid-β PET) in the Australian Imaging, Biomarkers and Lifestyle (AIBL) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Significant associations were observed between age acceleration using the Hannum epigenetic clock and cross-sectional hippocampal volume in AIBL and replicated in ADNI. In AIBL, several other findings were observed cross-sectionally, including a significant association between hippocampal volume and the Hannum and Phenoage epigenetic clocks. Further, significant associations were also observed between hippocampal volume and the Zhang and Phenoage epigenetic clocks within Amyloid-β positive individuals. However, these were not validated within the ADNI cohort. No associations between age acceleration and other Alzheimer’s disease-related phenotypes, including measures of cognition or brain Amyloid-β burden, were observed, and there was no association with longitudinal change in any phenotype. This study presents a link between age acceleration, as determined using DNA methylation, and hippocampal volume that was statistically significant across two highly characterised cohorts. The results presented in this study contribute to a growing literature that supports the role of epigenetic modifications in ageing and AD-related phenotypes

Bacterially mediated formation of carbonate concretions in the Oligocene Boom Clay of Northern Belgium

Carbonate concretions in the Oligocene Boom Clay in Northern Belgium grew as a result of bacterially mediated geochemical processes, Concretion distribution patterns are controlled by glacioeustatic controls on water depth and related sediment detrital carbonate contents, Bacterial remains are present throughout these early diagenetic concretions and can be observed by SEM analysis of etched carbonates. The oxygen isotopic composition (delta(18)O similar to 0 parts per thousand) Of the calcite in the concretions indicates early diagenetic growth close to the sediment-water interface, Negative carbon-isotope values (delta(13)C -17 to -22 parts per thousand) from concretion carbonates, as well as pyrite delta(34)S values of -15 to -45 parts per thousand, suggest precipitation resulting from bacterial sulfate reduction during shallow burial diagenesis, Additionally, organic components in the concretions are characteristic of the remains of sulfate- reducing bacteria

How to Build a High-Quality Library Collection in a Multi-Format Environment: Centralized Selection at University of Wyoming Libraries

In recent decades, the composition of academic library collections has shifted toward electronic formats, resulting in a more complicated publication landscape to be navigated by selectors. Additionally, the workload of public services librarians has become more weighted toward instruction and research support, putting more pressure on the time of liaison librarians tasked with collection development responsibilities. These shifts have prompted academic institutions, including University of Wyoming Libraries, to consider a restructuring of collection development responsibilities. This article describes the evolution and implementation of a centralized model of selection at UW Libraries