Cross-validation of cut-points in preschool children using different accelerometer placements and data axes

The present study cross-validated various cut-points to assess physical activity and sedentary behaviour in preschoolers, using hip- and wrist-worn accelerometers and both vertical axis and vector magnitude data. Secondly, we examined the influence of epoch length on time estimates of physical activity and sedentary behaviour. Sixty-four preschoolers (34 girls) wore two accelerometers, on their right hip and dominant wrist, during 1 hour of free play. Preschoolers’ activities were observed by two trained researchers. Area under the curve (AUC) was calculated for the receiving operating characteristic (ROC) curves as a measure of precision. AUC ranges were 0.603–0.723 for sedentary behaviour, 0.472–0.545 for light physical activity and 0.503–0.661 for moderate-to-vigorous physical activity (MVPA), indicating poor to fair precision. Percentage of time classified as sedentary behaviour, light or MVPA according to observation and accelerometer data varied largely between cut-points, accelerometer placements and axes. The influence of epoch length on time estimates was minimal across cut-points, except for one hip-based vector magnitude cut-point. Across all accelerometer placements and data axes, no set of cut-points demonstrated adequate precision for sedentary behaviour, light physical activity and MVPA. The highly variable and omnidirectional activity pattern of preschoolers may explain the lack of adequate cut-points

Impact of the Coronavirus Disease Pandemic on Health-Related Quality of Life of Patients with Inflammatory Bowel Disease

BACKGROUND: To learn from the crisis caused by the coronavirus disease (COVID-19) pandemic and be prepared for future pandemics, it is important to investigate the impact of this period on the wellbeing of patients with inflammatory bowel disease (IBD). AIMS: To describe the health-related quality of life (HRQoL) and disease control of IBD patients during the first wave of the COVID-19 pandemic in The Netherlands. METHODS: Between March 17 and July 1, 2020, patients aged 18 years and older with IBD from the Erasmus MC (Rotterdam, The Netherlands) were invited to complete online questionnaires at week 0, 2, 6 and 12. The Inflammatory Bowel Disease Questionnaire (IBDQ), the Inflammatory Bowel Disease Control-8 (IBD-control-8) and the numeric rating scale on fatigue were used. The evolution of the different outcomes over time was measured using mixed models. RESULTS: Of 1151 invited patients, 851 patients (67% CD and 33% UC or IBD-U) participated in the study (response rate 74%). No relevant changes in total scores were found over time for the IBDQ (effect estimate 0.006, 95% CI [− 0.003 to 0.015]) and IBD-control-8 (effect estimate 0.004, 95% CI [0.998–1.011]). There was a slight, increasing trend in fatigue scores over time (effect estimate 0.011, 95% CI [0.004, 0.019]). CONCLUSIONS: This first lock down due to the COVID-19 pandemic in The Netherlands did not impact on the HRQoL and disease control of patients with IBD. Up to date information may have contributed to a stable HRQoL in IBD patients even in an extreme period with restrictions and insecurities. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10620-021-07118-8

Kinetics and 28-day test-retest repeatability and reproducibility of [C-11]UCB-J PET brain imaging

[C-11]UCB-J is a novel radioligand that binds to synaptic vesicle glycoprotein 2A (SV2A). The main objective of this study was to determine the 28-day test-retest repeatability (TRT) of quantitative [C-11]UCB-J brain positron emission tomography (PET) imaging in Alzheimer's disease (AD) patients and healthy controls (HCs). Nine HCs and eight AD patients underwent two 60 min dynamic [C-11]UCB-J PET scans with arterial sampling with an interval of 28 days. The optimal tracer kinetic model was assessed using the Akaike criteria (AIC). Micro-/macro-parameters such as tracer delivery (K-1) and volume of distribution (V-T) were estimated using the optimal model. Data were also analysed for simplified reference tissue model (SRTM) with centrum semi-ovale (white matter) as reference region. Based on AIC, both 1T2k_V-B and 2T4k_V-B described the [C-11]UCB-J kinetics equally well. Analysis showed that whole-brain grey matter TRT for V-T, DVR and SRTM BPND were -2.2% +/- 8.5, 0.4% +/- 12.0 and -8.0% +/- 10.2, averaged over all subjects. [C-11]UCB-J kinetics can be well described by a 1T2k_V-B model, and a 60 min scan duration was sufficient to obtain reliable estimates for both plasma input and reference tissue models. TRT for V-T, DVR and BPND wa

Validation and test-retest repeatability performance of parametric methods for [11C]UCB-J PET

[(11)C]UCB-J is a PET radioligand that binds to the presynaptic vesicle glycoprotein 2A. Therefore, [(11)C]UCB-J PET may serve as an in vivo marker of synaptic integrity. The main objective of this study was to evaluate the quantitative accuracy and the 28-day test–retest repeatability (TRT) of various parametric quantitative methods for dynamic [(11)C]UCB-J studies in Alzheimer’s disease (AD) patients and healthy controls (HC). Eight HCs and seven AD patients underwent two 60-min dynamic [(11)C]UCB-J PET scans with arterial sampling over a 28-day interval. Several plasma-input based and reference-region based parametric methods were used to generate parametric images using metabolite corrected plasma activity as input function or white matter semi-ovale as reference region. Different parametric outcomes were compared regionally with corresponding non-linear regression (NLR) estimates. Furthermore, the 28-day TRT was assessed for all parametric methods. Spectral analysis (SA) and Logan graphical analysis showed high correlations with NLR estimates. Receptor parametric mapping (RPM) and simplified reference tissue model 2 (SRTM2) BP(ND), and reference Logan (RLogan) distribution volume ratio (DVR) regional estimates correlated well with plasma-input derived DVR and SRTM BP(ND). Among the multilinear reference tissue model (MRTM) methods, MRTM1 had the best correspondence with DVR and SRTM BP(ND). Among the parametric methods evaluated, spectral analysis (SA) and SRTM2 were the best plasma-input and reference tissue methods, respectively, to obtain quantitatively accurate and repeatable parametric images for dynamic [(11)C]UCB-J PET. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13550-021-00874-8

Simple measures of climate, soil properties and plant traits predict national scale grassland soil carbon stocks

1. Soil carbon (C) storage is a key ecosystem service. Soil C stocks play a vital role in soil fertility and climate regulation, but the factors that control these stocks at regional and national scales are unknown, particularly when their composition and stability are considered. As a result, their mapping relies on either unreliable proxy measures or laborious direct measurements. 2. Using data from an extensive national survey of English grasslands we show that surface soil (0-7cm) C stocks in size fractions of varying stability can be predicted at both regional and national scales from plant traits and simple measures of soil and climatic conditions. 3. Soil C stocks in the largest pool, of intermediate particle size (50-250 µm), were best explained by mean annual temperature (MAT), soil pH and soil moisture content. The second largest C pool, highly stable physically and biochemically protected particles (0.45-50 µm), was explained by soil pH and the community abundance weighted mean (CWM) leaf nitrogen (N) content, with the highest soil C stocks under N rich vegetation. The C stock in the small active fraction (250-4000 µm) was explained by a wide range of variables: MAT, mean annual precipitation, mean growing season length, soil pH and CWM specific leaf area; stocks were higher under vegetation with thick and/or dense leaves. 4. Testing the models describing these fractions against data from an independent English region indicated moderately strong correlation between predicted and actual values and no systematic bias, with the exception of the active fraction, for which predictions were inaccurate. 5. Synthesis and Applications: Validation indicates that readily available climate, soils and plant survey data can be effective in making local- to landscape-scale (1-100,000 km2) soil C stock predictions. Such predictions are a crucial component of effective management strategies to protect C stocks and enhance soil C sequestration

Comparison of dental topography of marmosets and tamarins (Callitrichidae) to other platyrrhine primates using a novel freeware pipeline

Dental topographic metrics (DTMs), which quantify different aspects of the shape of teeth, are powerful tools for studying dietary adaptation and evolution in mammals. Current DTM protocols usually rely on proprietary software, which may be unavailable to researchers for reasons of cost. We address this issue in the context of a DTM analysis of the primate clade Platyrrhini (“New World monkeys”) by: 1) presenting a large comparative sample of scanned second lower molars (m2s) of callitrichids (marmosets and tamarins), previously underrepresented in publicly available datasets; and 2) giving full details of an entirely freeware pipeline for DTM analysis and its validation. We also present an updated dietary classification scheme for extant platyrrhines, based on cluster analysis of dietary data extracted from 98 primary studies. Our freeware pipeline performs equally well in dietary classification accuracy of an existing sample of platyrrhine m2s (excluding callitrichids) as a published protocol that uses proprietary software when multiple DTMs are combined. Individual DTMs, however, sometimes showed very different results in classification accuracies between protocols, most likely due to differences in smoothing functions. The addition of callitrichids resulted in high classification accuracy in predicting diet with combined DTMs, although accuracy was considerably higher when molar size was included (90%) than excluded (73%). We conclude that our new freeware DTM pipeline is capable of accurately predicting diet in platyrrhines based on tooth shape and size, and so is suitable for inferring probable diet of taxa for which direct dietary information is unavailable, such as fossil species