160 research outputs found
Combined Effects of Estrogen and Mechanical Loading on Anterior Cruciate Ligament Fibroblast Biosynthesis
For some time, estrogen has been suspected to play a negative role in anterior cruciate ligament (ACL) fibroblast biosynthesis; however, reports on this issue have been controversial. In a recent study, our group demonstrated a negative combined effect of estrogen and mechanical loading on the gene expression of major extracellular matrix component molecules in ACL fibroblasts
Implicit Diffusion Models for Continuous Super-Resolution
Image super-resolution (SR) has attracted increasing attention due to its
wide applications. However, current SR methods generally suffer from
over-smoothing and artifacts, and most work only with fixed magnifications.
This paper introduces an Implicit Diffusion Model (IDM) for high-fidelity
continuous image super-resolution. IDM integrates an implicit neural
representation and a denoising diffusion model in a unified end-to-end
framework, where the implicit neural representation is adopted in the decoding
process to learn continuous-resolution representation. Furthermore, we design a
scale-controllable conditioning mechanism that consists of a low-resolution
(LR) conditioning network and a scaling factor. The scaling factor regulates
the resolution and accordingly modulates the proportion of the LR information
and generated features in the final output, which enables the model to
accommodate the continuous-resolution requirement. Extensive experiments
validate the effectiveness of our IDM and demonstrate its superior performance
over prior arts.Comment: 8 pages, 9 figures, published to CVPR202
The effect of warming on grassland evapotranspiration partitioning using laser-based isotope monitoring techniques
Author's manuscript made available in accordance with the publisher's policy.The proportion of transpiration (T) in total evapotranspiration (ET) is an important parameter that provides insight into the degree of biological influence on the hydrological cycles. Studies addressing the effects of climatic warming on the ecosystem total water balance are scarce, and measured warming effects on the T/ET ratio in field experiments have not been seen in the literature. In this study, we quantified T/ET ratios under ambient and warming treatments in a grassland ecosystem using a stable isotope approach. The measurements were made at a long-term grassland warming site in Oklahoma during the MayâJune peak growing season of 2011. Chamber-based methods were used to estimate the δ2H isotopic composition of evaporation (δE), transpiration (δT) and the aggregated evapotranspiration (δET). A modified commercial conifer leaf chamber was used for δT, a modified commercial soil chamber was used for δE and a custom built chamber was used for δET. The δE, δET and δT were quantified using both the Keeling plot approach and a mass balance method, with the CraigâGordon model approach also used to calculate δE. Multiple methods demonstrated no significant difference between control and warming plots for both δET and δT. Though the chamber-based estimates and the CraigâGordon results diverged by about 12â°, all methods showed that δE was more depleted in the warming plots. This decrease in δE indicates that the evaporation flux as a percentage of total water flux necessarily decreased for δET to remain constant, which was confirmed by field observations. The T/ET ratio in the control treatment was 0.65 or 0.77 and the ratio found in the warming treatment was 0.83 or 0.86, based on the chamber method and the CraigâGordon approach. Sensitivity analysis of the CraigâGordon model demonstrates that the warming-induced decrease in soil liquid water isotopic composition is the major factor responsible for the observed δE depletion and the temperature dependent equilibrium effects are minor. Multiple lines of evidence indicate that the increased T/ET ratio under warming is caused mainly by reduced evaporation
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Differential responses of carbon-degrading enzyme activities to warming: implications for soil respiration
Extracellular enzymes catalyze rateâlimiting steps in soil organic matter decomposi-tion, and their activities (EEAs) play a key role in determining soil respiration (SR).Both EEAs and SR are highly sensitive to temperature, but their responses to cli-mate warming remain poorly understood. Here, we present a metaâanalysis on theresponse of soil cellulase and ligninase activities and SR to warming, synthesizingdata from 56 studies. We found that warming significantly enhanced ligninase activ-ity by 21.4% but had no effect on cellulase activity. Increases in ligninase activitywere positively correlated with changes in SR, while no such relationship was foundfor cellulase. The warming response of ligninase activity was more closely related tothe responses of SR than a wide range of environmental and experimental method-ological factors. Furthermore, warming effects on ligninase activity increased withexperiment duration. These results suggest that soil microorganisms sustain longâterm increases in SR with warming by gradually increasing the degradation of therecalcitrant carbon pool
Parameter identifiability, constraint, and equifinality in data assimilation with ecosystem models
Association between abnormal plasma metabolism and brain atrophy in alcohol-dependent patients
ObjectiveIn this study, we aimed to characterize the plasma metabolic profiles of brain atrophy and alcohol dependence (s) and to identify the underlying pathogenesis of brain atrophy related to alcohol dependence.MethodsWe acquired the plasma samples of alcohol-dependent patients and performed non-targeted metabolomic profiling analysis to identify alterations of key metabolites in the plasma of BA-ADPs. Machine learning algorithms and bioinformatic analysis were also used to identify predictive biomarkers and investigate their possible roles in brain atrophy related to alcohol dependence.ResultsA total of 26 plasma metabolites were significantly altered in the BA-ADPs group when compared with a group featuring alcohol-dependent patients without brain atrophy (NBA-ADPs). Nine of these differential metabolites were further identified as potential biomarkers for BA-ADPs. Receiver operating characteristic curves demonstrated that these potential biomarkers exhibited good sensitivity and specificity for distinguishing BA-ADPs from NBA-ADPs. Moreover, metabolic pathway analysis suggested that glycerophospholipid metabolism may be highly involved in the pathogenesis of alcohol-induced brain atrophy.ConclusionThis plasma metabolomic study provides a valuable resource for enhancing our understanding of alcohol-induced brain atrophy and offers potential targets for therapeutic intervention
Direct and indirect effects of climatic variations on the interannual variability in net ecosystem exchange across terrestrial ecosystems
Climatic variables not only directly affect the interannual variability (IAV) in net ecosystem exchange of CO2 (NEE) but also indirectly drive it by changing the physiological parameters. Identifying these direct and indirect paths can reveal the underlying mechanisms of carbon (C) dynamics. In this study, we applied a path analysis using flux data from 65 sites to quantify the direct and indirect climatic effects on IAV in NEE and to evaluate the potential relationships among the climatic variables and physiological parameters that represent physiology and phenology of ecosystems. We found that the maximum photosynthetic rate was the most important factor for the IAV in gross primary productivity (GPP), which was mainly induced by the variation in vapour pressure deficit. For ecosystem respiration (RE), the most important drivers were GPP and the reference respiratory rate. The biome type regulated the direct and indirect paths, with distinctive differences between forests and non-forests, evergreen needleleaf forests and deciduous broadleaf forests, and between grasslands and croplands. Different paths were also found among wet, moist and dry ecosystems. However, the climatic variables can only partly explain the IAV in physiological parameters, suggesting that the latter may also result from other biotic and disturbance factors. In addition, the climatic variables related to NEE were not necessarily the same as those related to GPP and RE, indicating the emerging difficulty encountered when studying the IAV in NEE. Overall, our results highlight the contribution of certain physiological parameters to the IAV in C fluxes and the importance of biome type and multi-year water conditions, which should receive more attention in future experimental and modelling research
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