37 research outputs found
Ionic Liquids as Working Fluids for Heat Storage Applications: Decomposition Behavior of N-Butyl-N-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate
Ionic liquids (ILs) represent promising working fluids to be used in thermal energy storage (TES) technologies thanks to their peculiar properties, such as low volatility, high chemical stability, and high heat capacity. Here, we studied the thermal stability of the IL N-butyl-N-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate ([BmPyrr]FAP), a potential working fluid for TES applications. The IL was heated at 200 degrees C for up to 168 h either in the absence or in contact with steel, copper, and brass plates to simulate the conditions used in TES plants. High-resolution magic angle spinning nuclear magnetic resonance spectroscopy was found to be useful for the identification of the degradation products of both the cation and the anion, thanks to the acquisition of H-1, C-13, P-31, and F-19-based experiments. In addition, elemental analysis was performed on the thermally degraded samples by inductively coupled plasma optical emission spectroscopy and energy dispersive X-ray spectroscopy. Our analysis shows a significant degradation of the FAP anion upon heating for more than 4 h, even in the absence of the metal/alloy plates; on the other hand, the [BmPyrr] cation displays a remarkable stability also when heated in contact with steel and brass
Efikasna metoda analize reflektorskih nizova
In this paper, we present an efficient technique based on the extension of the Adaptive Integral Method (AIM) that allows the full-wave analysis of microstrip reflectarrays. The reflectarray patches can have arbitrary shape and orientation and are modelled with subdomain triangular basis functions. The method makes use of a 2D-FTT/CG scheme, reducing the CPU time per iteration to O(N logN) and the memory requirement to O(N).U radu je opisana efikasna metoda analize zasnovana na proĆĄirenju adaptivne integralne metode (AIM) koja omoguÄuje punovalnu analizu mikrotrakastih reflektorskih nizova. PloÄice, elementi reflektorskih nizova, mogu imati proizvoljni oblik i orijentaciju pa su modelirane trokutasnim baznim funkcijama s domenom na dijelu ploÄice. Metoda rabi 2D-FTT/CG shemu, i pri tome smanjuje potrebno vrijeme rada raÄunala na O(N logN) i memorijske zahtjeve na O(N)
A blood DNA methylation biomarker for predicting short-term risk of cardiovascular events
Background. Recent evidence highlights the epidemiological value of blood DNA methylation (DNAm) as surrogate biomarker for exposure to risk factors for non-communicable diseases (NCD). DNAm surrogate of exposures predict diseases and longevity better than self-reported or measured exposures in many cases. Consequently, disease prediction models based on blood DNAm surrogates may outperform current state-of-art prediction models. This study aims to develop novel DNAm surrogates for cardiovascular diseases (CVD) risk factors and develop a composite biomarker predictive of CVD risk. We compared the prediction performance of our newly developed risk score with the state-of-art DNAm risk scores for cardiovascular diseases, the ânext-generationâ epigenetic clock DNAmGrimAge, and the prediction model based on traditional risk factors SCORE2.
Results. Using data from the EPIC Italy cohort, we derived novel DNAm surrogates for BMI, blood pressure, fasting glucose and insulin, cholesterol, triglycerides, and coagulation biomarkers. We validated them in four independent datasets from Europe and the US. Further, we derived a DNAmCVDscore predictive of the time-to-CVD event as a combination of several DNAm surrogates. ROC curve analyses show that DNAmCVDscore outperforms previously developed DNAm scores for CVD risk and SCORE2 for short-term CVD risk. Interestingly, the performance of DNAmGrimAge and DNAmCVDscore was comparable (slightly lower for DNAmGrimAge, although the differences were not statistically significant).
Conclusions. We described novel DNAm surrogates for CVD risk factors useful for future molecular epidemiology research, and we described a blood DNAm-based composite biomarker, DNAmCVDscore, predictive of short-term cardiovascular events. Our results highlight the usefulness of DNAm surrogate biomarkers of risk factors in epigenetic epidemiology to identify high-risk populations. In addition, we provide further evidence on the effectiveness of prediction models based on DNAm surrogates and discuss methodological aspects for further improvements. Finally, our results encourage testing this approach for other NCD diseases by training and developing DNAm surrogates for disease-specific risk factors and exposures
The history of rainfall data time-resolution in a wide variety of geographical areas
Collected rainfall records by gauges lead to key forcings in most hydrological studies. Depending on sensor type and recording systems, such data are characterized by different time-resolutions (or temporal aggregations), ta. We present an historical analysis of the time-evolution of ta based on a large database of rain gauge networks operative in many study areas. Globally, ta data were collected for 25,423 rain gauge stations across 32 geo graphic areas, with larger contributions from Australia, USA, Italy and Spain. For very old networks early re cordings were manual with coarse time-resolution, typically daily or sometimes monthly. With a few exceptions, mechanical recordings on paper rolls began in the first half of the 20th century, typically with ta of 1 h or 30 min. Digital registrations started only during the last three decades of the 20th century. This short period limits investigations that require long time-series of sub-daily rainfall data, e.g, analyses of the effects of climate change on short-duration (sub-hourly) heavy rainfall. In addition, in the areas with rainfall data characterized for many years by coarse time-resolutions, annual maximum rainfall depths of short duration can be potentially underestimated and their use would produce errors in the results of successive applications. Currently, only 50% of the stations provide useful data at any time-resolution, that practically means ta = 1 min. However, a sig nificant reduction of these issues can be obtained through the information content of the present database. Finally, we suggest an integration of the database by including additional rain gauge networks to enhance its usefulness particularly in a comparative analysis of the effects of climate change on extreme rainfalls of short duration available in different locations