42 research outputs found

    Determination of composition and structure of spongy bone tissue in human head of femur by Raman spectral mapping

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    Biomechanical properties of bone depend on the composition and organization of collagen fibers. In this study, Raman microspectroscopy was employed to determine the content of mineral and organic constituents and orientation of collagen fibers in spongy bone in the human head of femur at the microstructural level. Changes in composition and structure of trabecula were illustrated using Raman spectral mapping. The polarized Raman spectra permit separate analysis of local variations in orientation and composition. The ratios of Îœ2PO43−/Amide III, Îœ4PO43−/Amide III and Îœ1CO32−/Îœ2PO43− are used to describe relative amounts of spongy bone components. The Îœ1PO43−/Amide I ratio is quite susceptible to orientation effect and brings information on collagen fibers orientation. The results presented illustrate the versatility of the Raman method in the study of bone tissue. The study permits better understanding of bone physiology and evaluation of the biomechanical properties of bone

    Resilient cooling strategies – A critical review and qualitative assessment

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    The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out

    Development of design calculations for radiant ceiling panels incorporating phase change materials (PCMs)

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    Thermally active building systems (TABS) show significant benefits such as providing peak load shifting, peak load reductions, and energy savings. Phase change material (PCM) applications with water circulation have benefits similar to TABS, but PCMs can store more heat per unit volume than concrete due to the latent heat exchange. Radiant panels with PCM can be applied in building retrofit, which gives this application a significant advantage compared to TABS. A design methodology for determining heat flux does not exist though for dimensioning a radiant ceiling system that incorporates PCM. Design methods according to standards for TABS – ISO 11855-2 and for radiant panels – ISO 18566-3 were investigated. Five radiant ceiling panels incorporating PCM were selected from Denmark, Canada, Germany, the Czech Republic and Latvia. The resulting heat flux between the panel and conditioned space, i.e. the room, following methods represented in the standards, were compared with the measured or simulated values reported in the literature. The comparison showed that the calculation for TABS (ISO 11855-2) led to similar results to the measured or simulated values

    Art. 1.1475/ringraziamenti

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    Abstract. -OBJECTIVE: Studies in animals have provided key evidence that antagonizing TNF-α α is a viable therapeutic strategy for diffuse severe brain injury. This study is planned to prevent post-traumatic secondary tissue damages in rat diffuse severe brain injury model, which is induced by alone or combined administration of Etanercept and lithium chloride (LiCl). MATERIALS AND METHODS: Male SpragueDawley rats were used in the current study. Rats were divided into 5 groups. Trauma was not induced and treatment was not applied to rats of Sham group. For rats of Trauma+Saline group, saline 0.9% was administered via intraperitoneal (i.p.) route at dose of 1 mg/100 g body weight 1 hour after trauma. For rats of Trauma+Etanercept group, Etanercept was administered via i.p. route at dose of 5 mg/kg body weight 1 hour after trauma. For rats of Trauma+LiCl group, LiCl was administered via i.p. route at dose of 50 mg/kg body weight 1 hour after trauma. For rats of Etanercept+LiCl group, Etanercept and LiCl were administered via i.p. route at dose of 5 mg/kg body weight and 50 mg/kg body weight, respectively, 1 hour after trauma. Serum glial fibrillary acidic protein (GFAP) and Tau levels were analyzed with ELISA. For analyses H&E, TUNEL, GFAP and TNF-α α staining methods were used. RESULTS: We demonstrate that Etanercept treatment reduced the TBI-induced brain tissues alteration, reduced the expression of TNF-α α and improve edema and axonal swelling. We observed a significant decrease in TNF-α α and GFAP positivity after LiCl was administered. CONCLUSIONS: The findings obtained in this study suggest that the combination therapy with Etanercept and LiCl decreased neurona

    Homogenizing GPS Integrated Water Vapor Time Series: Benchmarking Break Detection Methods on Synthetic Data Sets

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    We assess the performance of different break detection methods on three sets of benchmark data sets, each consisting of 120 daily time series of integrated water vapor differences. These differences are generated from the Global Positioning System (GPS) measurements at 120 sites worldwide, and the numerical weather prediction reanalysis (ERA-Interim) integrated water vapor output, which serves as the reference series here. The benchmark includes homogeneous and inhomogeneous sections with added nonclimatic shifts (breaks) in the latter. Three different variants of the benchmark time series are produced, with increasing complexity, by adding autoregressive noise of the first order to the white noise model and the periodic behavior and consecutively by adding gaps and allowing nonclimatic trends. The purpose of this “complex experiment” is to examine the performance of break detection methods in a more realistic case when the reference series are not homogeneous. We evaluate the performance of break detection methods with skill scores, centered root mean square errors (CRMSE), and trend differences relative to the trends of the homogeneous series. We found that most methods underestimate the number of breaks and have a significant number of false detections. Despite this, the degree of CRMSE reduction is significant (roughly between 40% and 80%) in the easy to moderate experiments, with the ratio of trend bias reduction is even exceeding the 90% of the raw data error. For the complex experiment, the improvement ranges between 15% and 35% with respect to the raw data, both in terms of RMSE and trend estimations

    Homogenizing GPS Integrated Water Vapor Time Series: Benchmarking Break Detection Methods on Synthetic Data Sets

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    International audienceWe assess the performance of different break detection methods on three sets of benchmark data sets, each consisting of 120 daily time series of integrated water vapor differences. These differences are generated from the Global Positioning System (GPS) measurements at 120 sites worldwide, and the numerical weather prediction reanalysis (ERA-Interim) integrated water vapor output, which serves as the reference series here. The benchmark includes homogeneous and inhomogeneous sections with added nonclimatic shifts (breaks) in the latter. Three different variants of the benchmark time series are produced, with increasing complexity, by adding autoregressive noise of the first order to the white noise model and the periodic behavior and consecutively by adding gaps and allowing nonclimatic trends. The purpose of this "complex experiment" is to examine the performance of break detection methods in a more realistic case when the reference series are not homogeneous. We evaluate the performance of break detection methods with skill scores, centered root mean square errors (CRMSE), and trend differences relative to the trends of the homogeneous series. We found that most methods underestimate the number of breaks and have a significant number of false detections. Despite this, the degree of CRMSE reduction is significant (roughly between 40% and 80%) in the easy to moderate experiments, with the ratio of trend bias reduction is even exceeding the 90% of the raw data error. For the complex experiment, the improvement ranges between 15% and 35% with respect to the raw data, both in terms of RMSE and trend estimations
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