A contribution for thermoeconomic modelling: A methodology proposal

This work presents a thermoeconomic optimization methodology for the analysis and design of energy systems. This methodology involves economic aspects related to the exergy conception, in order to develop a tool to assist the equipment selection, operation mode choice as well as to optimize the thermal plants design. It also presents the concepts related to exergy in a general scope and in thermoeconomics which combines the thermal sciences principles (thermodynamics, heat transfer, and fluid mechanics) and the economic engineering in order to rationalize energy systems investment decisions, development and operation. Even in this paper, it develops a thermoeconomic methodology through the use of a simple mathematical model, involving thermodynamics parameters and costs evaluation, also defining the objective function as the exergetic production cost. The optimization problem evaluation is developed for two energy systems. First is applied to a steam compression refrigeration system and then to a cogeneration system using backpressure steam turbine.     

High-resolution electrocardiography in acute myocardial infarct

The author starts by highlighting the importance of risk stratification in patients who have survived a myocardial infarction. High resolution electrocardiography, also called signal-averaged electrocardiography (SAECG), appears in this setting as a diagnostic tool that, by providing important information about the way the intraventricular conduction of the electrical impulse is made, contributes to the characterization of the arrhythmogenic substrate, which is the basis of ventricular tachycardia and fibrillation. By resorting to the averaging of the electrocardiographic signal, SAECG enables us to detect ventricular late potentials whenever the analysis of that signal is made in time-domain. Further details, which will enrich the information on ventricular activation, can be obtained if the analysis is made in the frequency-domain (spectral analysis). The importance of detecting abnormalities in the SAECG recordings lies in the fact that those abnormalities are related to the occurrence of ventricular tachycardia and fibrillation, which are responsible for arrhythmic death. After referring to the criteria of positivity of SAECG and its reproducibility, the author approaches the most important part of the paper: the clinical applications of SAECG. After focusing on the interest of the method in noncoronary conditions, its usefulness in patients with acute myocardial infarction is pointed out. The author then mentions the prevalence of abnormalities in SAECG in patients with acute myocardial infarction and emphasizes the interest of the method in risk stratification. The author then presents the results of his Group in what concerns prevalence and prognosis. Finally, the author refers to the application of SAECG in other forms of coronary artery disease besides myocardial infarction.     

Multistrategy Theory Revision: Induction and Abduction in INTHELEX

This paper presents an integration of induction and abduction in INTHELEX, a prototypical incremental learning system. The refinement operators perform theory revision in a search space whose structure is induced by a quasi-ordering, derived from Plotkin's -subsumption, compliant with the principle of Object Identity. A reduced complexity of the refinement is obtained, without a major loss in terms of expressiveness. These inductive operators have been proven ideal for this search space. Abduction supports the inductive operators in the completion of the incoming new observations. Experiments have been run on a standard dataset about family trees as well as in the domain of document classification to prove the effectiveness of such multistrategy incremental learning system with respect to a classical batch algorithm.     

Waste Characterization by Scanning Electron Microscopy for Material Recovery

Worldwide legislation coming into force requires considering new waste streams in order to achieve higher targets for material recovery and recycling. It is necessary, therefore, to manage waste materials in which different components are linked together and contaminants of various origins are present. Waste materials thus need to be treated that have a complex and often unknown composition and present different structural, morphological, and chemical properties. The physical and chemical characterization of solid waste is an essential step for the development of suitable treatment strategies, aimed at the recovery of one or more waste components. Scanning electron microscopy appears to be in most cases very helpful for waste characterization, providing information on material size, shape, structure, texture, distribution, and composition. Examples of waste characterization through scanning electron microscopy, finalized to material recovery, are reported. The waste materials taken into consideration include solids of different nature, such as spent lead batteries, cathode ray tubes (CRT), and printed circuit boards (PCB).     

Mono- and bi-functional arenethiols as surfactants for gold nanoparticles: synthesis and characterization

Stable gold nanoparticles stabilized by different mono and bi-functional arenethiols, namely, benzylthiol and 1,4-benzenedimethanethiol, have been prepared by using a modified Brust's two-phase synthesis. The size, shape, and crystalline structure of the gold nanoparticles have been determined by high-resolution electron microscopy and full-pattern X-ray powder diffraction analyses. Nanocrystals diameters have been tuned in the range 2 ÷ 9 nm by a proper variation of Au/S molar ratio. The chemical composition of gold nanoparticles and their interaction with thiols have been investigated by X-ray photoelectron spectroscopy. In particular, the formation of networks has been observed with interconnected gold nanoparticles containing 1,4-benzenedimethanethiol as ligand.     

Effects of fermentation and rye flour on microstructure and volatile compounds of chestnut flour based sourdoughs

The study is aimed at developing a new cereal-based product, with increased nutritional quality, by using natural fermentation of blends of chestnut and rye flour. In spite of the remarkable similarity, the technological potential of combinations of both flours has never been explored before. Three spontaneous chestnut/rye sourdough fermentations were performed over a period of twelve days with daily back-slopping. Samples taken at all refreshment steps were used for culture-dependent and culture-independent evaluation of the microbiota present. Dominant species basically overlapped to those associated to sourdoughs strengthened with chestnut flour, such as Pediococcus pentosaceus or Weissella paramesenteroides. Microstructures, evaluated by means of Scanning Electron Microscopy, revealed the presence in chestnut sourdoughs of a distinguishable network surrounding starch granules, while rye flour-added sourdoughs showed a less structured matrix. By gas chromatography coupled to mass spectrometry, 51 volatile organic compounds were identified at 24 h and after prolonged fermentation. Within volatile organic compounds, alcohols, esters, acids, aldehydes and ketones, all well-known flavour compounds in sourdough fermentation, appeared as dominant. The PCA discriminated the sourdoughs into three distinct clusters and highlighted a clear influence of fermentation time on the volatile composition of sourdoughs.     

Vesicular Glutamate Release from Feeder-FreehiPSC-Derived Neurons

Human-induced pluripotent stem cells (hiPSCs) represent one of the main and powerful tools for the in vitro modeling of neurological diseases. Standard hiPSC-based protocols make use of animal-derived feeder systems to better support the neuronal differentiation process. Despite their efficiency, such protocols may not be appropriate to dissect neuronal specific properties or to avoid interspecies contaminations, hindering their future translation into clinical and drug discovery approaches. In this work, we focused on the optimization of a reproducible protocol in feeder-free conditions able to generate functional glutamatergic neurons. This protocol is based on a generation of neuroprecursor cells differentiated into human neurons with the administration in the culture medium of specific neurotrophins in a Geltrex-coated substrate. We confirmed the efficiency of this protocol through molecular analysis (upregulation of neuronal markers and neurotransmitter receptors assessed by gene expression profiling and expression of the neuronal markers at the protein level), morphological analysis, and immunfluorescence detection of pre-synaptic and post-synaptic markers at synaptic boutons. The hiPSC-derived neurons acquired Ca²⁺-dependent glutamate release properties as a hallmark of neuronal maturation. In conclusion, our study describes a new methodological approach to achieve feeder-free neuronal differentiation from hiPSC and adds a new tool for functional characterization of hiPSC-derived neurons.     

TENET: a new hybrid network architecture for adversarial defense

International Journal of Information Security - Deep neural network (DNN) models are widely renowned for their resistance to random perturbations. However, researchers have found out that these...