Advanced Knowledge Application in Practice

The integration and interdependency of the world economy leads towards the creation of a global market that offers more opportunities, but is also more complex and competitive than ever before. Therefore widespread research activity is necessary if one is to remain successful on the market. This book is the result of research and development activities from a number of researchers worldwide, covering concrete fields of research

Development and application of synchronized wide-area power grid measurement

Phasor measurement units (PMUs) provide an innovative technology for real-time monitoring of the operational state of entire power systems and significantly improve power grid dynamic observability. This dissertation focuses on development and application of synchronized power grid measurements. The contributions of this dissertation are as followed:First, a novel method for successive approximation register analog to digital converter control in PMUs is developed to compensate for the sampling time error caused by the division remainder between the desirable sampling rate and the oscillator frequency. A variable sampling interval control method is presented by interlacing two integers under a proposed criterion. The frequency of the onboard oscillator is monitored in using the PPS from GPS.Second, the prevalence of GPS signal loss (GSL) on PMUs is first investigated using real PMU data. The correlation between GSL and time, spatial location, solar activity are explored via comprehensive statistical analysis. Furthermore, the impact of GSL on phasor measurement accuracy has been studied via experiments. Several potential solutions to mitigate the impact of GSL on PMUs are discussed and compared.Third, PMU integrated the novel sensors are presented. First, two innovative designs for non-contact PMUs presented. Compared with conventional synchrophasors, non-contact PMUs are more flexible and have lower costs. Moreover, to address nonlinear issues in conventional CT and PT, an optical sensor is used for signal acquisition in PMU. This is the first time the utilization of an optical sensor in PMUs has ever been reported.Fourth, the development of power grid phasor measurement function on an Android based mobile device is developed. The proposed device has the advantages of flexibility, easy installation, lower cost, data visualization and built-in communication channels, compared with conventional PMUs.Fifth, an identification method combining a wavelet-based signature extraction and artificial neural network based machine learning, is presented to identify the location of unsourced measurements. Experiments at multiple geographic scales are performed to validate the effectiveness of the proposed method using ambient frequency measurements. Identification accuracy is presented and the factors that affect identification performance are discussed

VOLTAGE-SENSITIVE DYE IMAGING OF RAT PIRIFORM CORTEX BEFORE AND AFTER KINDLING

To determine the role of inhibitory cells in the propagation of activity in the rat piriform cortex (PC) before and after kindling, we used voltage-sensitive dye imaging technique to follow the membrane potential changes in three layers of the PC after stimulating the lateral olfactory tract (LOT) with beta and gamma frequencies. Stimulation of LOT was followed by propagation of excitatory (in layer II) and inhibitory responses (in layer III) through the PC. Decreasing the inhibition by applying gabazine, a GABAa- receptor antagonist, decreased the inhibitory responses and increased the excitatory responses in the control rats; however, it did not affect the excitatory and inhibitory responses in the kindled rats. Furthermore, cutting the slice below the layer II decreased the both responses. Thus, we concluded that disinhibition of layer III intemeurons is necessary for principle cells firing and kindling can result in seizures by increasing disinhibition in layer III of PC

Advanced photonic and electronic systems - WILGA 2017

WILGA annual symposium on advanced photonic and electronic systems has been organized by young scientist for young scientists since two decades. It traditionally gathers more than 350 young researchers and their tutors. Ph.D students and graduates present their recent achievements during well attended oral sessions. Wilga is a very good digest of Ph.D. works carried out at technical universities in electronics and photonics, as well as information sciences throughout Poland and some neighboring countries. Publishing patronage over Wilga keep Elektronika technical journal by SEP, IJET by PAN and Proceedings of SPIE. The latter world editorial series publishes annually more than 200 papers from Wilga. Wilga 2017 was the XL edition of this meeting. The following topical tracks were distinguished: photonics, electronics, information technologies and system research. The article is a digest of some chosen works presented during Wilga 2017 symposium. WILGA 2017 works were published in Proc. SPIE vol.10445

Engineering and Assessing Cardiac Tissue Complexity

Cardiac tissue engineering is very much in a current focus of regenerative medicine research as it represents a promising strategy for cardiac disease modelling, cardiotoxicity testing and cardiovascular repair. Advances in this field over the last two decades have enabled the generation of human engineered cardiac tissue constructs with progressively increased functional capabilities. However, reproducing tissue-like properties is still a pending issue, as constructs generated to date remain immature relative to native adult heart. Moreover, there is a high degree of heterogeneity in the methodologies used to assess the functionality and cardiac maturation state of engineered cardiac tissue constructs, which further complicates the comparison of constructs generated in different ways. Here, we present an overview of the general approaches developed to generate functional cardiac tissues, discussing the different cell sources, biomaterials, and types of engineering strategies utilized to date. Moreover, we discuss the main functional assays used to evaluate the cardiac maturation state of the constructs, both at the cellular and the tissue levels. We trust that researchers interested in developing engineered cardiac tissue constructs will find the information reviewed here useful. Furthermore, we believe that providing a unified framework for comparison will further the development of human engineered cardiac tissue constructs displaying the specific properties best suited for each particular application

Advanced microstructured platforms for neuroscience: from lab-on-chips for circadian clock studies to next generation bionic 3D brain tissue models

In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus is considered the master circadian pacemaker which coordinates circadian rhythms in the central nervous system (CNS) and across the entire body. The SCN receives light input from the eyes through the retinohypothalamic tract and then it synchronizes other clocks in the CNS and periphery, thus orchestrating rhythms throughout the body. However, little is known about how so many cellular clocks within and across brain circuits can be effectively synchronized to entrain the coordinated expression of clock genes in cells distributed all over the brain. In this work I investigated the possible implication of two possible pathways: i) paracrine factors-mediated synchronization and ii) astrocytes-mediated synchronization. To study these pathways, I adopted an in vitro research model that I developed based on a lab-on-a-chip microfluidic device designed and realized in our laboratory. This device allows growing and compartmentalizing distinct neural populations connected through a network of astrocytes or through a cell-free channel in which the diffusion of paracrine factors is allowed. By taking advantage of this device, upon its validation, I synchronized neural clocks in one compartment and analyzed, in different experimental conditions, the induced expression of clock genes in a distant neural network grown in the second compartment. Results show that both pathways can be involved, but might have different roles. Neurons release factors that can diffuse to synchronize a neuronal population. The same factors can also synchronize astrocytes that, in turn, can transmit astrocyte-mediated molecular clocks to more distant neuronal populations. This is supported by experimental data obtained using microfluidic devices featuring different channel lengths. I found that paracrine factors-mediated synchronization occurs only in the case of a short distance between neuronal populations. On the contrary, interconnecting astrocytes define an active channel that can transfer molecular clocks to neural populations also at long distances. The study of possibly involved signaling factors indicate that paracrine factors-mediated synchronization occurs through GABA signaling, while astrocytes-mediated synchronization involves both GABA and glutamate. These findings strength the importance of the synergic regulation of clock genes among neurons and astrocytes, and identify a previously unknown role of astrocytes as active cells in distributing signals to regulate the expression of clock genes in the brain. Preliminary results also show a correlation between astrocyte reactivity and local alterations in neuronal synchronization, thus opening a new scenario for future studies in which disease-induced astrocyte reactivity might be linked to alterations in clock gene expression.Three-dimensional (3D) brain models hold great potential for the generation of functional in vitro models to advance studies on human brain development, diseases and possible therapies. The routine exploitation of such models, however, is hindered by the lack of technologies to chronically monitor the activity of neural aggregates in three dimensions. A promising new approach consists in growing bio-artificial 3D brain model systems with seamless tissue-integrated biosensing artificial microdevices. Such devices could provide a platform for in-tissue sensing of diverse biologically relevant parameters. To date there is very little information on how to control the extracellular integration of such microscale devices into neuronal 3D cell aggregates. In this direction, in the present work I contributed to investigated the growth of hybrid neurospheroids obtained by the aggregation of silicon sham microchips (100x100x50\u3bcm3) with primary cortical cells. Interestingly, by coating microchips with different adhesion-promoting molecules, we reveal that surface functionalization can tune the integration and final 3D location of self-standing microdevices into neurospheroids. Morphological and functional characterization suggests that the presence of an integrated microdevice does not alter spheroid growth, cellular composition, nor network activity and maturation. Finally, we also demonstrate the feasibility of separating cells and microchips from formed hybrid neurospheroids for further single-cell analysis, and quantifications confirm an unaltered ratio of neurons and glia. These results uncover the potential of surface-engineered self-standing microdevices to grow untethered three-dimensional brain-tissue models with inbuilt bioelectronic sensors at predefined sites

Electrophysiology

The outstanding evolution of recording techniques paved the way for better understanding of electrophysiological phenomena within the human organs, including the cardiovascular, ophthalmologic and neural systems. In the field of cardiac electrophysiology, the development of more and more sophisticated recording and mapping techniques made it possible to elucidate the mechanism of various cardiac arrhythmias. This has even led to the evolution of techniques to ablate and cure most complex cardiac arrhythmias. Nevertheless, there is still a long way ahead and this book can be considered a valuable addition to the current knowledge in subjects related to bioelectricity from plants to the human heart

NASA Thesaurus. Volume 1: Hierarchical listing

There are 16,713 postable terms and 3,716 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary