Nonlinear Adaptive Signal Processing Improves the Diagnostic Quality of Transabdominal Fetal Electrocardiography

The abdominal fetal electrocardiogram (fECG) conveys valuable information that can aid clinicians with the diagnosis and monitoring of a potentially at risk fetus during pregnancy and in childbirth. This chapter primarily focuses on noninvasive (external and indirect) transabdominal fECG monitoring. Even though it is the preferred monitoring method, unlike its classical invasive (internal and direct) counterpart (transvaginal monitoring), it may be contaminated by a variety of undesirable signals that deteriorate its quality and reduce its value in reliable detection of hypoxic conditions in the fetus. A stronger maternal electrocardiogram (the mECG signal) along with technical and biological artifacts constitutes the main interfering signal components that diminish the diagnostic quality of the transabdominal fECG recordings. Currently, transabdominal fECG monitoring relies solely on the determination of the fetus’ pulse or heart rate (FHR) by detecting RR intervals and does not take into account the morphology and duration of the fECG waves (P, QRS, T), intervals, and segments, which collectively convey very useful diagnostic information in adult cardiology. The main reason for the exclusion of these valuable pieces of information in the determination of the fetus’ status from clinical practice is the fact that there are no sufficiently reliable and well-proven techniques for accurate extraction of fECG signals and robust derivation of these informative features. To address this shortcoming in fetal cardiology, we focus on adaptive signal processing methods and pay particular attention to nonlinear approaches that carry great promise in improving the quality of transabdominal fECG monitoring and consequently impacting fetal cardiology in clinical practice. Our investigation and experimental results by using clinical-quality synthetic data generated by our novel fECG signal generator suggest that adaptive neuro-fuzzy inference systems could produce a significant advancement in fetal monitoring during pregnancy and childbirth. The possibility of using a single device to leverage two advanced methods of fetal monitoring, namely noninvasive cardiotocography (CTG) and ST segment analysis (STAN) simultaneously, to detect fetal hypoxic conditions is very promising

Validation of vertical ground heat exchanger design methodologies

[EN] This work presents a validation of two common methods for designing vertical ground heat exchangers. Both a simulation-based design tool and the ASHRAE handbook design equation are used to find design lengths for four different real systems, using actual experimental data, including building loads as well as physical parameters as inputs. The measured minimum and maximum ground heat exchanger exiting fluid temperatures were used as the design constraint. The simulation-based design tool predicted the borehole length to within 6% in all cases, while the ASHRAE handbook design equation yielded systems with errors from ¿21% to 167%. Most of this error can be explained by the way loads are represented in the ASHRAE handbook equation, with differences in the borehole thermal resistance also playing a smaller part. TheASHRAE handbook equation relies on a very simple load representation; although this allows it to be used as a simple hand calculation, it also precludes it achieving acceptable accuracy. It does not appear to be possible to revise the ASHRAE handbook equation so as to both significantly improve its accuracy and allow its use in a simple hand calculation.Cullin, J.; Spitler, JD.; Montagud Montalvá, CI.; Ruiz Calvo, F.; Rees, S.; Naicker, S.; Konecny, P.... (2015). Validation of vertical ground heat exchanger design methodologies. Science and Technology for the Built Environment. 21(2):137-149. doi:10.1080/10789669.2014.974478S13714921

Effect of Streptococcus uberis on Gamma Delta T Cell Phenotype in Bovine Mammary Gland

In this study, we focused analyzing γδ T cells during bovine mammary gland inflammation induced by Streptococcus uberis. A mammary gland cell suspension was obtained using lavage 24, 48, 72, and 168 h after intramammary-induced infection. The proportion of lymphocytes increased during the entire week in which inflammation was present. The γδ T cells were also elevated during inflammation, reaching their peak at 72 h following induced inflammation. The percentage of apoptotic lymphocytes continually increased, with the highest proportion occurring 168 h after S. uberis infection. The results show that γδ T cells may be involved in the resolution of inflammation in bovine mammary glands, with the apoptosis of those cells potentially playing an important role.O

Limitations of FEM modelling of chloride diffusion when considering different parameters of binary and ternary concrete mixtures

The numerical modelling of chloride diffusion in concrete structures requires an appropriate description of input parameters. The main inputs for the model are the diffusion coefficient of concrete and derived aging factor. The model itself can be susceptible to the values of these parameters because of the size of the finite elements and size of the time step. Due to the potential use in probabilistic calculations, which requires millions of simulations, it is desirable to create a highly optimized model. It is important to pay attention to the accuracy of the calculation, but also to its calculation time. The presented results show the possible limits of the finite element model of the diffusion in a concrete structure. This is demonstrated on the reference ordinary Portland cement mixture and 32 various binary and ternary concrete mixtures, which show a significant effect of different diffusion coefficients and aging factors on the overall convergence. This study provides guidance on which extreme material parameters, out of the potential range, may adversely affect model results

Random variation and correlation of the weather data series – evaluation and simulation using bounded histograms

The contribution is focused on the random variation and correlation of input parameters for the climate data description. The climate data such as ambient temperature, solar intensity, wind speed and direction are of the random nature. The description of ambient temperature can be based on the climate data time series in the form of climatic “load duration curve”. Particular input parameters such as ambient temperature and solar radiation have a significant correlation. The attention is paid especially to the evaluation and simulation application of the histograms using Monte Carlo type process considering correlation of particular parameters

Random variation and correlation of the weather data series – evaluation and simulation using bounded histograms

The contribution is focused on the random variation and correlation of input parameters for the climate data description. The climate data such as ambient temperature, solar intensity, wind speed and direction are of the random nature. The description of ambient temperature can be based on the climate data time series in the form of climatic “load duration curve”. Particular input parameters such as ambient temperature and solar radiation have a significant correlation. The attention is paid especially to the evaluation and simulation application of the histograms using Monte Carlo type process considering correlation of particular parameters

Durability of structural lightweight waste aggregate concrete – electrical resistivity

While examination of the durability of ordinary concrete mixtures is of interest of many research groups, only limited amount of information is available in terms of lightweight concrete tested under the same conditions. In this case, the durability related to the chloride ion diffusion is investigated on the relatively new type of structural lightweight concrete, which, above all, contains waste material – red ceramics sand, and artificial expanded clay coarse aggregate. Used aggregates were fully soaked before adding into the concrete mixture, so also the internal curing effect is considered in terms of the degradation process. Cylindrical specimens made of plain concrete matrix and with added fibre in various percentage quantities were tested to examine the durability of the mixture by measuring the electrical resistivity. The results are compared to the findings from a similar project. The paper deals with aspects influencing the results of chloride diffusion in concrete