Morphological Characterization and Effective Thermal Conductivity of Dual-Scale Reticulated Porous Structures

Reticulated porous ceramic (RPC) made of ceria are promising structures used in solar thermochemical redox cycles for splitting CO2 and H2O. They feature dual-scale porosity with mm-size pores for effective radiative heat transfer during reduction and µm-size pores within its struts for enhanced kinetics during oxidation. In this work, the detailed 3D digital representation of the complex dual-scale RPC is obtained using synchrotron submicrometer tomography and X-ray microtomography. Total and open porosity, pore size distribution, mean pore diameter, and specific surface area are extracted from the computer tomography (CT) scans. The 3D digital geometry is then applied in direct pore level simulations (DPLS) of Fourier’s law within the solid and the fluid phases for the accurate determination of the effective thermal conductivity at each porosity scale and combined, and for fluid-to-solid thermal conductivity from 10−5 to 1. Results are compared to predictions by analytical models for structures with a wide range of porosities 0.09–0.9 in both the strut’s µm-scale and bulk’s mm-scale. The morphological properties and effective thermal conductivity determined in this work serve as an input to volume-averaged models for the design and optimization of solar chemical reactors

Morphological Characterization and Effective Thermal Conductivity of Dual-Scale Reticulated Porous Structures

Reticulated porous ceramic (RPC) made of ceria are promising structures used in solar thermochemical redox cycles for splitting CO2 and H2O. They feature dual-scale porosity with mm-size pores for effective radiative heat transfer during reduction and µm-size pores within its struts for enhanced kinetics during oxidation. In this work, the detailed 3D digital representation of the complex dual-scale RPC is obtained using synchrotron submicrometer tomography and X-ray microtomography. Total and open porosity, pore size distribution, mean pore diameter, and specific surface area are extracted from the computer tomography (CT) scans. The 3D digital geometry is then applied in direct pore level simulations (DPLS) of Fourier’s law within the solid and the fluid phases for the accurate determination of the effective thermal conductivity at each porosity scale and combined, and for fluid-to-solid thermal conductivity from 10−5 to 1. Results are compared to predictions by analytical models for structures with a wide range of porosities 0.09–0.9 in both the strut’s µm-scale and bulk’s mm-scale. The morphological properties and effective thermal conductivity determined in this work serve as an input to volume-averaged models for the design and optimization of solar chemical reactors.ISSN:1996-194

The Swiss Sleep House Bern—A New Approach to Sleep Medicine

Sleep is essential for health, well-being, creativity, and productivity. Sleep loss and sleep–wake circadian disorders (SWCDs) affect at least one in three individuals but are underdiagnosed and undertreated for different reasons: First, the importance of sleep health and, second, the burden of sleep loss and SWCDs are underestimated. Third, education in sleep medicine is insufficient and health care-related sleep research is underdeveloped. Fourth, the validation and implementation of tele-sleep medicine approaches and novel devices to monitor SWCDs are still insufficient. Fifth, the reimbursement of sleep medicine in most countries is inadequate and the availability of specialized care is limited to a few centers. The Swiss Sleep House Bern (SSHB) was founded in 2022 to address these challenges and eventually promote better care for patients with SWCDs and improve sleep health for the broader population. The interdisciplinary and interprofessional team of the SSHB, which is integrated in the Bernese Interdisciplinary Sleep-Wake-Epilepsy Center, links sleep specialists with primary care providers to offer a rapid and accessible triage and first-level management of sleep complaints and SWCDs. The SSHB also promotes awareness and offers educational programs on sleep health and SWCDs, performs health care research, and fosters the implementation of new technologies, data science, and telemedicine into clinical routine

Identification of molecular apocrine breast tumours by microarray analysis

Previous microarray studies on breast cancer identified multiple tumour classes, of which the most prominent, named luminal and basal, differ in expression of the oestrogen receptor alpha gene (ER). We report here the identification of a group of breast tumours with increased androgen signalling and a 'molecular apocrine' gene expression profile. Tumour samples from 49 patients with large operable or locally advanced breast cancers were tested on Affymetrix U133A gene expression microarrays. Principal components analysis and hierarchical clustering split the tumours into three groups: basal, luminal and a group we call molecular apocrine. All of the molecular apocrine tumours have strong apocrine features on histological examination (P=0.0002). The molecular apocrine group is androgen receptor (AR) positive and contains all of the ER-negative tumours outside the basal group. Kolmogorov-Smirnov testing indicates that oestrogen signalling is most active in the luminal group, and androgen signalling is most active in the molecular apocrine group. ERBB2 amplification is commoner in the molecular apocrine than the other groups. Genes that best split the three groups were identified by Wilcoxon test. Correlation of the average expression profile of these genes in our data with the expression profile of individual tumours in four published breast cancer studies suggest that molecular apocrine tumours represent 8-14% of tumours in these studies. Our data show that it is possible with microarray data to divide mammary tumour cells into three groups based on steroid receptor activity: luminal (ER+ AR+), basal (ER- AR-) and molecular apocrine (ER- AR+).SCOPUS: ar.jinfo:eu-repo/semantics/publishe