French database of building airtightness, statistical analyses of about 215,000 measurements: impacts of buildings characteristics and seasonal variations

International audienceThe French database of building airtightness has been fed by measurement performed by qualified testers since 2006. In 2015 and 2016, the database was enriched by 63,409 and 65,958 measurements respectively, which is 74% more than in 2014, making the total number of measurements about 215,000. However, residential buildings (multi-family and single dwellings) account for almost all of measurements, only 4% of tests are performed in non-residential buildings. Indeed, since 2013 the French EP-regulation requires a limit for airtightness level for all new dwellings. The justification of the building airtightness level shall be done either by an airtightness test or by the application of a certified quality management approach. In the first part, this paper summarizes the recent results of the database regarding buildings' characteristics (building area, main material, ventilation system, insulation...). The second part proposes first results regarding the evolution of air permeability. In single dwellings, the air permeability at 4 Pa (per unit of envelope area) slightly decreases from year to year with a mean value around 0.41 m 3 .h-1 .m-2 in 2015. In multi-family buildings, the yearly mean air permeability fluctuates between 0.60 and 0.65 m 3 .h-1 .m-2. In non-residential buildings, it fluctuates around 1 m 3 .h-1 .m-2. However non-residential buildings cover a wide variety of buildings. A special focus is made on non-residential buildings depending on the use of the building and its size. The last part of this paper deals with the impact of the seasonal variations on the measured air permeability in single dwellings depending on climatic zones and buildings construction materials (wood, concrete and brick constructions). An impact of seasonal variations on air permeability is only observed in the case of wood constructions, with slightly higher values during summer in the south of France in particular

Assessment of long-term and mid-term building airtightness durability: field study of 61 French low energy single-family dwellings

International audienceThe French ongoing research project "Durabilit'air" (2016-2019) aims at improving our knowledge on the variation of buildings airtightness through onsite measurement and accelerated ageing in laboratory controlled conditions. This paper presents the final results of the second task of the project. This task deals with the quantification and qualification of the durability of building airtightness of single detached houses. It is done through field measurement at mid-term (MT) and long-term (LT) scales. We first present the field measurement protocol. For the MT campaign, a sample of 30 new single-detached houses has been selected nationwide. During the study, the airtightness of each building was measured once per year over a 3-year period. A part of this sample (5 houses) was also measured twice per year during two different seasons in order to investigate the impact of seasonal variation. In addition, the air permeability of a window was measured once per year over the 3-year period in 5 houses. The LT campaign was carried out with a second sample of 31 existing single-detached houses constructed during the last 10 years. The airtightness of each house was measured once. A specific measurement protocol was defined after a detailed literature review. The main challenge is to understand the variations of the airtightness and to identify whether it is related to the products/assembly ageing, the maintenance conditions or other factors such as the occupants' behaviour. The protocol is based on the standard ISO 9972 for the measurement method of building air permeability with additional requirements for the measurement conditions. It also includes a detailed qualitative leakage detection and questionnaire for occupants. Secondly, this paper presents the construction characteristics of both samples. All houses were tested upon completion. The air changes per hour at 50 Pa pressure difference (n50) of both samples show the same mean value of 1.4 h-1 , with larger variations among the LT sample. Finally, we discuss measurement results. Regarding MT sample, the air permeability slightly increases during the first year (mean increase by 18%), and then stabilizes during the second and third year. However, for some houses with exposed timber framing, n50 has increased by more than 100%. Regarding LT campaign, the air permeability (n50) show a similar increase after 3-10 years with a mean value of 20%. Measurements performed during two different seasons did not show a significant impact of seasonal variation. The results show globally an increase in the number of detected leakages for all houses, but this increase is not always correlated with the change in air permeability. For 10 houses of both samples, the building airtightness has improved. For 6 houses, this improvement is maybe due to the building material (wood), the maintenance of windows, or the sealing of leaks by occupants but for 4 houses, we have not been able to explain this improvement

Onsite evaluation of building airtightness durability: Long-term and mid-term field measurement study of 61 French low energy single family dwellings

International audienceThe increasing weight of building leakages energy impact on the overall energy performance of low-energy buildings led to a better understanding of the actual airtightness performance of buildings. However, low expertise is available today on the durability of airtightness products in mid-and long-term scales. The French ongoing research project "Durabilit'air" (2016-2019) aims at improving our knowledge on the variation of buildings airtightness through onsite measurement and accelerated ageing in laboratory controlled conditions. This paper is issued from the second task of the "Durabilit'air" project. This task deals with the quantification and qualification of the durability of building airtightness of single detached houses. It is done through field measurement at mid-term (MT) and long-term (LT) scales. This paper first presents the field measurement protocol. For the MT campaign, a sample of 30 new single-detached dwellings has been selected nationwide. During the study, the airtightness of each building is to be measured once per year over a 3-year period. A part of this sample is to be also measured twice per year in order to investigate the impact of seasonal variations. The LT campaign is to be carried out with a second sample of 31 existing single-detached dwellings constructed during the last 10 years. The airtightness of each dwelling is to be measured once. A specific measurement protocol was defined after a detailed literature review. The protocol is mainly based on the standard ISO 9972 for the measurement method with additional requirements for the measurement conditions (same tester, same calibrated measurement device, same building preparation, same pressure difference sequences, same season…). It also includes a detailed qualitative leakage detection and questionnaire for occupants. The main challenge is to understand the variations of the airtightness and to identify whether it is related to the products/assembly ageing, the maintenance conditions or other factors such as the occupants' behaviour. Secondly, this paper presents the 61 dwelling samples construction characteristics. All dwellings were tested upon completion. The air flow rates at 4 Pa per envelope area excluding lower floor of both samples show the same mean value around 0.3 m 3 .h-1 .m-2 (n50 of 1.4 h-1), with larger variations among the LT sample. Finally, we discuss first measurement results. Regarding MT sample, results after 1-2 years show a slight increase of airflow rate at 50 PA (q50) with a median value of +6%. However, with exposed timber framing, q50 has increased by more than 100%. Regarding LT campaign, measurements results after 3-10 years show a more important increase of q50 with a median value of 28%. The measurement campaigns and data analysis will continue over 2018 to complete the work in order to better understand the in situ variations of the buildings' envelope airtightness. KEYWORDS Airtightness durability, field measurements, building envelope, low-energy dwelling 1 INTRODUCTION The increasing weight of building leakages energy impact on the overall performance of low-energy buildings led to a better understanding and characterization of the actual airtightness performance of buildings. Several European countries have already included in their EP-regulation mandatory requirements regarding the building airtightness. This is the case in France, where the EP-regulation requires a limit airtightness level for residential buildings that must be justified by measurement. However, low expertise is available today on the durability of building airtightness and its evolution in mid-and long-term scales. The French ongoing research project "Durabilit'air" is conducted since 2016 for a 42-month period, in order to improve our knowledge on the variation of buildings airtightness through onsite measurement campaigns and accelerated ageing in laboratory controlled conditions. As part of this project, a comprehensive literature review about building airtightness durability was realized by (Leprince et al., 2017). This review showed an important evolution over time of the air permeability in real buildings, with an increase of more than twice in some cases. The air permeability seems to increase in the 3 first years and then stabilise. This paper is issued from the second task of the "Durabilit'air" project. This task deals with the quantification and qualification of the durability of building airtightness of single detached houses. It is done through field measurement at mid-term (MT) and long-term (LT) scales. This paper presents the first results of both MT and LT measurements

Evaluating assumptions of scales for subjective assessment of thermal environments – Do laypersons perceive them the way, we researchers believe?

International audienc

Cu-II(atsm) Attenuates Neuroinflammation

Background: Neuroinflammation and biometal dyshomeostasis are key pathological features of several neurodegenerative diseases, including Alzheimer's disease (AD). Inflammation and biometals are linked at the molecular level through regulation of metal buffering proteins such as the metallothioneins. Even though the molecular connections between metals and inflammation have been demonstrated, little information exists on the effect of copper modulation on brain inflammation. Methods: We demonstrate the immunomodulatory potential of the copper bis(thiosemicarbazone) complex Cu-II(atsm) in an neuroinflammatory model in vivo and describe its anti-inflammatory effects on microglia and astrocytes in vitro. Results: By using a sophisticated in vivo magnetic resonance imaging (MRI) approach, we report the efficacy of Cu-II(atsm) in reducing acute cerebrovascular inflammation caused by peripheral administration of bacterial lipopolysaccharide (LPS). Cu-II(atsm) also induced anti-inflammatory outcomes in primary microglia [significant reductions in nitric oxide (NO), monocyte chemoattractant protein 1 (MCP-1), and tumor necrosis factor (TNF)] and astrocytes [significantly reduced NO, MCP-1, and interleukin 6 (IL-6)] in vitro. These anti-inflammatory actions were associated with increased cellular copper levels and increased the neuroprotective protein metallothionein-1 (MT1) in microglia and astrocytes. Conclusion: The beneficial effects of Cu-II(atsm) on the neuroimmune system suggest copper complexes are potential therapeutics for the treatment of neuroinflammatory conditions.Peer reviewe

Essential versus accessory aspects of cell death: recommendations of the NCCD 2015

Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as ‘accidental cell death’ (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. ‘Regulated cell death’ (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to classify it into a few subtypes, which often (but not always) exhibit stereotyped morphologic features. Nonetheless, efficiently inhibiting the processes that are commonly thought to cause RCD, such as the activation of executioner caspases in the course of apoptosis, does not exert true cytoprotective effects in the mammalian system, but simply alters the kinetics of cellular demise as it shifts its morphologic and biochemical correlates. Conversely, bona fide cytoprotection can be achieved by inhibiting the transduction of lethal signals in the early phases of the process, when adaptive responses are still operational. Thus, the mechanisms that truly execute RCD may be less understood, less inhibitable and perhaps more homogeneous than previously thought. Here, the Nomenclature Committee on Cell Death formulates a set of recommendations to help scientists and researchers to discriminate between essential and accessory aspects of cell death

Necroptosis: a novel way of regulated necrosis with large pathophysiological implications

Necrosis is a histopathologic term but also refers to a cell death process that was generally considered as accidental due to physicochemical injury. Necrosis is characterized by swelling of the cell (oncosis), plasma membrane rupture, and release of intracellular content. Recently, a regulated form of necrosis has been identified, termed necroptosis, in which receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like (MLKL) proteins play a crucial role through the formation of the so-called necrosome complex. Genetic ablation of these genes and the development of RIPK1 inhibitors, the so-called necrostatins, demonstrated that necroptosis can be targeted and suggest that it may play a crucial role in many different important inflammatory, infectious, and trauma-related disorders such as inflammatory graft rejection, cardiac infarction and brain trauma, acute pancreatitis, inflammatory bowel disease, ophthalmologic diseases, skin inflammation, systemic inflammatory response syndrome, atherosclerosis, and viral infection. However, in view of the pleiotropic role of RIPK1, RIPK3, and MLKL, it is also conceivable that other processes such as inflammasome formation are cotargeted in vivo, leading to the spectacular protective effects

Altered B-lymphopoiesis in mice with deregulated thrombopoietin signaling

Published online: 02 November 2017Thrombopoietin (TPO) is the master cytokine regulator of megakaryopoiesis. In addition to regulation of megakaryocyte and platelet number, TPO is important for maintaining proper hematopoietic stem cell (HSC) function. It was previously shown that a number of lymphoid genes were upregulated in HSCs from Tpo -/- mice. We investigated if absent or enhanced TPO signaling would influence normal B-lymphopoiesis. Absent TPO signaling in Mpl -/- mice led to enrichment of a common lymphoid progenitor (CLP) signature in multipotential lineage-negative Sca-1+c-Kit+ (LSK) cells and an increase in CLP formation. Moreover, Mpl -/- mice exhibited increased numbers of PreB2 and immature B-cells in bone marrow and spleen, with an increased proportion of B-lymphoid cells in the G1 phase of the cell cycle. Conversely, elevated TPO signaling in Tpo Tg mice was associated with reduced B-lymphopoiesis. Although at steady state, peripheral blood lymphocyte counts were normal in both models, Mpl -/- Eµ-myc mice showed an enhanced preneoplastic phase with increased numbers of splenic PreB2 and immature B-cells, a reduced quiescent fraction, and augmented blood lymphocyte counts. Thus, although Mpl is not expressed on lymphoid cells, TPO signaling may indirectly influence B-lymphopoiesis and the preneoplastic state in Myc-driven B-cell lymphomagenesis by lineage priming in multipotential progenitor cells.Amanda E. Au, Marion Lebois, Starling A. Sim, Ping Cannon, Jason Corbin, Pradnya Gangatirkar, Craig D. Hyland, Diane Moujalled, Angelika Rutgersson, Fatme Yassinson, Benjamin T. Kile, Kylie D. Mason, Ashley P. Ng, Warren S. Alexander, Emma C. Josefsso

Cyclic AMP induces IPC leukemia cell apoptosis via CRE-and CDK-dependent Bim transcription

The IPC-81 cell line is derived from the transplantable BNML model of acute myelogenic leukemia (AML), known to be a reliable predictor of the clinical efficiency of antileukemic agents, like the first-line AML anthracycline drug daunorubicin (DNR). We show here that cAMP acted synergistically with DNR to induce IPC cell death. The DNR-induced death differed from that induced by cAMP by (1) not involving Bim induction, (2) being abrogated by GSK3β inhibitors, (3) by being promoted by the HSP90/p23 antagonist geldanamycin and truncated p23 and (4) by being insensitive to the CRE binding protein (CREB) antagonist ICER and to cyclin-dependent protein kinase (CDK) inhibitors. In contrast, the apoptosis induced by cAMP correlated tightly with Bim protein expression. It was abrogated by Bim (BCL2L11) downregulation, whether achieved by the CREB antagonist ICER, by CDK inhibitors, by Bim-directed RNAi, or by protein synthesis inhibitor. The forced expression of BimL killed IPC-81WT cells rapidly, Bcl2-overexpressing cells being partially resistant. The pivotal role of CREB and CDK activity for Bim transcription is unprecedented. It is also noteworthy that newly developed cAMP analogs specifically activating PKA isozyme I (PKA-I) were able to induce IPC cell apoptosis. Our findings support the notion that AML cells may possess targetable death pathways not exploited by common anti-cancer agents