Achieving energy sustainability in future neighborhoods through building refurbishment and energy hub concept: a case study in Hemberg-Switzerland

This study aims to investigate the role of distributed generation through the energy hub concept and refurbishment of existing buildings. More specifically, a computational platform combining (i) the urban energy modelling tool CitySimPro and (ii) the microgrid simulation tool Homer is developed. The energy flow on hourly basis is assessed for buildings in Hemberg, a small village in Switzerland, considering occupancy, lighting and appliances profiles, as defined by the Swiss normative. System design of the energy hub is optimized considering three energy system configurations: (i) present scenario, (ii) energy hub catering electrical demand, (iii) energy hub catering both electrical and thermal demand including heat pumps. Results for the integration of an energy hub on site show that the current use of renewables can be increased from 0.15% to over 60% by integrating heat pumps in the city energy network

Improving the energy sustainability of a Swiss village through building renovation and renewable energy integration

The integration of renewable energy technologies and building renovation are the two main procedures for improving energy sustainability of buildings at neighborhood scale. It is difficult, however, to optimize these procedures simultaneously. This study focuses on improving energy sustainability of Hemberg, a Swiss village with a population of about 900, through optimizing these two procedures. For this purpose a computational platform was developed, combining software CitySim, HOMER Pro, QGIS and Rhinoceros. The energy demand on hourly basis for the buildings in the village was analyzed through comparing the current demand with that after retrofitting according to the Swiss energy labels (i) Minergie and (ii) Minergie-P. Swiss energy maps were used to identify the most promising renewable energy sources while three scenarios were considered for solar PV integration and energy system improvements. The first scenario presents the current condition in the village, while the second scenario explores improvements in electricity generation and the third in both electricity and heat generation. The results show that retrofitting of all buildings according to Minergie reduces the space heating demand by 70–85% and reduces the fluctuations in energy demand, thereby allowing the integration of more renewable energy. According to the simulations, building-integrated solar PV panels can cover the total annual energy demand of the village when considering the Minergie and Minergie-P scenarios. However, the energy system assessment shows that it is difficult to reach beyond 60% when integrating non-dispatchable renewable energy technologies. Finally, and more importantly, integration of wind energy at system level has an important impact in the hub

Multivariate haplotype analysis of 96 sulci opening for 15,612 UK-Biobank subjects

International audienceImaging genetic studies of large control cohorts such as UK Biobank enable to assess the range of normal variations in brain structures. Previous studies by our group have shown that the width of several cortical sulci is associated with a variant in the upstream region of KCNK2 gene even if this effect is corrected with age. Here we propose to analyze in a multivariate setup the associations between sets of genetic variants and multiple sulci widths. The genetic variants we consider are sets of SNPs of known phase called haplotypes, taken from the upstream region of KCNK2 gene. To the best of our knowledge, multivariate analysis in imaging genetics has never been used in haplotype studies. Our method was able to recover the expected association signal and uncover new associations between imaging data and genetic variants

Genome-wide haplotype association study in imaging genetics using whole-brain sulcal openings of 16,304 UK Biobank subjects

International audienceNeuroimaging-genetics cohorts gather two types of data: brain imaging and genetic data. They allow the discovery of associations between genetic variants and brain imaging features. They are invaluable resources to study the influence of genetics and environment in the brain features variance observed in normal and pathological populations. This study presents a genome-wide haplotype analysis for 123 brain sulcus opening value (a measure of sulcal width) across the whole brain that include 16,304 subjects from UK Biobank. Using genetic maps, we defined 119,548 blocks of low recombination rate distributed along the 22 autosomal chromosomes and analyzed 1,051,316 haplotypes. To test associations between haplotypes and complex traits, we designed three statistical approaches. Two of them use a model that includes all the haplotypes for a single block, while the last approach considers each haplotype independently. All the statistics produced were assessed as rigorously as possible. Thanks to the rich imaging dataset at hand, we used resampling techniques to assess False Positive Rate for each statistical approach in a genome-wide and brain-wide context. The results on real data show that genome-wide haplotype analyses are more sensitive than single-SNP approach and account for local complex Linkage Disequilibrium (LD) structure, which makes genome-wide haplotype analysis an interesting and statistically sound alternative to the single-SNP counterpart

A study of feasibility for genome-wide haplotype association of complex traits in imaging genetics

International audienceImaging-genetics cohorts allow to find associations between genotyped variants and brain imaging features. They are invaluable tools to evaluate the part of genetics and environment in the brain characteristic variance observed in normal and pathological populations. The present analyses were conducted using the 2018 UK Biobank (UKB) data release, and included 15,040 subjects for which sulcal opening, a measure of sulcus width, are extracted for 126 sulci using BrainVisa/Morphologist pipeline. Based on genetic maps, continuous blocks of high-confidence phase are extracted using the haplotype dataset of UK Biobank. The feasibility study analyzes 13,942 haplotypes of 1,756 blocks on chromosome 21, obtained with a stringent block definition, and shows that block-based test seems underpowered compared to haplotype-based association test

Variation of 4 MV X-ray dose rate in fractionated irradiation strongly impacts biological endothelial cell response in vitro

International audienceComparisons of X-ray beam dose rates are scarce although these beams are widely used in medical diagnosis or radiotherapy. We have recently demonstrated in vitro and in vivo, that for a single dose of irradiation, the relative biological effectiveness (RBE) deviates from 1 when changing the dose rate of high energy X-ray beams. To further investigate the impact of the dose rate on RBE, in this study we performed in vitro fractionated irradiations by using the same two dose rates (0.63 and 2.5 Gy.min-1) of high-energy X-rays (both at 4 MV) on normal endothelial cells (HUVECs). We studied the viability/mortality, measured cellular senescence by flow cytometry and performed gene analysis on custom arrays. Taken together, these experiments show that the RBE of photons deviates from 1 when varying the dose rate of high-energy X-rays in fractionated irradiations. These results strengthen the interest of multiparametric analysis approaches in providing an accurate evaluation of the outcomes of irradiated cells in support of clonogenic assays, especially when such assays are not feasible

Variation of 4 MV X-ray dose rate strongly impacts biological response both in vitro and in vivo

International audienceBased on classic clonogenic assay, it is accepted by the scientific community that, whatever the energy or the dose rate, the relative biological effectiveness of X-rays is equal to 1. However, although X-ray beams are widely used in diagnosis, interventional medicine and radiotherapy, comparisons of their dose rates are scarce. We therefore assessed in vitro the effects of high-energy X-rays at two dose rates (0.63 and 2.5 Gy/min) using normal endothelial cells (HUVECs) by using clonogenic assay, measuring viability/mortality, studying the cell cycle and cellular senescence by flow cytometry and by performing gene analysis on custom arrays. In order to consolidate these data, we performed localized irradiation of exteriorized small intestine at 0.63 and 2.5 Gy/min. Interestingly, in vivo validation has shown a significantly higher loss of weight at the higher dose when irradiating to 19 Gy a small fragment of exteriorized small intestine of C57Bl6J mice. Nevertheless, no significant differences were observed in lesioned scores between the two dose rates, while bordering epithelium staining indicated twofold greater severe damage at 2.5 Gy/min compared to 0.63 Gy/min at one week post-irradiation. Taken together, these experiments systematically show more adverse effects of high energy X-rays at 2.5 Gy/min, while the relative biological effectiveness of photons is around 1, whatever the quality of the X-ray beam. These results strongly suggest that multiparametric analysis should be considered in support of clonogenic assay