A comparison of measured and estimated electric energy use and the impact of assumed occupancy pattern

The use of building performance simulation (BPS) tools to guide decisions during the design process in its early stages requires making assumptions. That is as the design specification, information about building use and future external climate are not available. This may lead to differences between the buildings performance in operation and its predicted performance. The aim of the presented work is to assess the impact of the building use on observed differences in performance. Parameters of concern are occupation period, occupancy density, electrical energy use and sensible heat gains from equipment and light fittings. The results of the study show that the difference between estimated and measured local electric energy use is below 10%. The important parameters related to the office use are identified as occupation period and heat gains from light fittings. In case of the considered building the use of medium high internal heat gains would have lead to overestimating the cooling demand by 30%. The identified parameters should be considered with great care when using BPS–tools for guiding the design of office buildings as they contribute significantly to the accuracy of simulation results

Thrombin receptor deficiency leads to a high bone mass phenotype by decreasing the RANKL/OPG ratio.

Contains fulltext : 154292.pdf (publisher's version ) (Closed access)Thrombin and its receptor (TR) are, respectively, expressed in osteoclasts and osteoblasts. However, their physiological roles on bone metabolism have not been fully elucidated. Here we investigated the bone microarchitecture by micro-computed tomography (muCT) and demonstrated increased trabecular and cortical bone mass in femurs of TR KO mice compared to WT littermates. Trabecular thickness and connectivity were significantly enhanced. The physiological role of TR on both inorganic and organic phases of bone is illustrated by a significant increase in BMD and a decrease in urinary deoxypyridinoline (DPD) crosslink concentration in TR KO mice. Moreover, TR KO cortical bone expanded and had a higher polar moment of inertia (J), implying stronger bone. Bone histomorphometry illustrated unaltered osteoblast and osteoclast number and surface in femoral metaphyses, indicating that thrombin/TR regulates osteoblasts and osteoclasts at functional levels. Serum analysis showed a decrease in RANKL and an increase in osteoprotegerin (OPG) levels and reflected a reduced RANKL/OPG ratio in the TR KO group. In vitro experiments using MC3T3 pre-osteoblasts demonstrated a TR-dependent stimulatory effect of thrombin on the RANKL/OPG ratio. This effect was blocked by TR antagonist and p42/p44-ERK inhibitor. In addition, thrombin also intensified p42/p44-ERK expression and phosphorylation. In conclusion, the thrombin/TR system maintains normal bone remodeling by activating RANKL and limiting OPG synthesis by osteoblasts through the p42/44-ERK signaling pathway. Consequently, TR deficiency inhibits osteoclastogenesis, resulting in a high bone mass phenotype.1 maart 201