The specific heat is frequency dependent in highly viscous liquids. By solving the full one-dimensional thermoviscoelastic problem analytically it is shown that, because of thermal expansion and the fact that mechanical stresses relax on the same time scale as the enthalpy relaxes, the plane thermal-wave method does not measure the isobaric frequency-dependent specific heat c{p}(omega) . This method rather measures a "longitudinal" frequency-dependent specific heat, a quantity defined and detailed here that is in between c{p}(omega) and c{V}(omega) . This result means that no reliable wide-frequency measurements of c{p}(omega) on liquids approaching the calorimetric glass transition exist. We briefly discuss consequences for experiment.
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http://dx.doi.org/10.1103/PhysRevE.75.041502 | DOI Listing |
Alzheimers Dement
December 2024
Ohio State University College of Medicine, Neurobiology of Aging & Resilience Center, Columbus, OH, USA.
Background: The cerebrovasculature is an essential component of brain homeostasis. Cerebrovascular disorders are associated with an increased risk for neurodegenerative diseases, including Alzheimer's disease (AD). However, the mechanisms by which cerebrovascular dysfunction contributes to neurodegeneration are poorly understood.
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December 2024
Rush University Medical Center, Chicago, IL, USA.
Background: Abnormal brain insulin signaling has been associated with Alzheimer's disease pathology and a faster rate of late-life cognitive decline. However, the underlying mechanisms remain unclear. In this study, we examined whether AD-related cortical proteins identified using targeted-proteomics play a role in the association of brain insulin signaling and cognitive decline.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
Background: Alzheimer's Disease (AD) presents complex molecular heterogeneity, influenced by a variety of factors including heterogeneous phenotypic, genetic, and neuropathologic presentations. Regulation of gene expression mechanisms is a primary interest of investigations aiming to uncover the underlying disease mechanisms and progression.
Method: We generated bulk RNA-sequencing in prefrontal cortex from 565 AD brain samples (non-Hispanic Whites, n = 399; Hispanics, n = 113; African American, n = 12) across six U.
ACS Appl Mater Interfaces
January 2025
ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia.
Effective heat management is critical for improving energy efficiency and minimizing environmental impact. Passive radiative heat management systems rely on specific materials and design configurations to naturally modulate temperature, enhance system reliability, and decrease operational costs by modulating infrared light. However, their static nature proves insufficient in dynamic settings experiencing significant temperature fluctuations.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
February 2025
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk 660036, Russian Federation.
The crystal structures and hyperfine magnetic parameters of EuFe(BO) and mixed EuLaFe(BO) were studied over a wide temperature range in order to analyze correlations of the structural and magnetic features and the phase transitions in multiferroic compounds of the rare-earth iron borate family. The chemical compositions of the crystals are reported from X-ray fluorescence analysis. The crystal structures of EuFe(BO) and EuLaFe(BO) were determined using single-crystal X-ray diffraction in the temperature range 25-500 K.
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