A skillful balance of theoretical considerations and practical know-how Backed by a team of expert contributors, the Second Edition of this highly acclaimed publication brings a solid understanding ...of impedance spectroscopy to students, researchers, and engineers in physical chemistry, electrochemistry, and physics. Starting with general principles, the book moves on to explain in detail practical applications for the characterization of materials in electrochemistry, semiconductors, solid electrolytes, corrosion, solid-state devices, and electrochemical power sources. The book covers all of the topics needed to help readers identify whether impedance spectroscopy may be an appropriate method for their particular research problem. The book helps readers quickly grasp how to apply their new knowledge of impedance spectroscopy methods to their own research problems through the use of unique features such as: * Step-by-step instructions for setting up experiments and then analyzing the results * Theoretical considerations for dealing with modeling, equivalent circuits, and equations in the complex domain * Best measurement methods for particular systems and alerts to potential sources of errors * Equations for the most widely used impedance models * Figures depicting impedance spectra of typical materials and devices * Extensive references to the scientific literature for more information on particular topics and current research This Second Edition incorporates the results of the last two decades of research on the theories and applications of impedance spectroscopy. Most notably, it includes new chapters on batteries, supercapacitors, fuel cells, and photochromic materials. A new chapter on commercially available measurement systems reflects the emergence of impedance spectroscopy as a mainstream research tool. With its balanced focus on both
theory and practical problem solving, Impedance Spectroscopy: Theory, Experiment, and Applications, Second Edition serves as an excellent graduate-level textbook as well as a hands-on guide and reference for researchers and engineers.
Therapeutic options for the treatment of an increasing variety of cancers have been expanded by the introduction of a new class of drugs, commonly referred to as checkpoint blocking agents, that ...target the host immune system to positively modulate anti-tumor immune response. Although efficacy of these agents has been linked to a pre-existing level of tumor immune infiltrate, it remains unclear why some patients exhibit deep and durable responses to these agents while others do not benefit. To examine the influence of tumor genetics on tumor immune state, we interrogated the relationship between somatic mutation and copy number alteration with infiltration levels of 7 immune cell types across 40 tumor cohorts in The Cancer Genome Atlas. Levels of cytotoxic T, regulatory T, total T, natural killer, and B cells, as well as monocytes and M2 macrophages, were estimated using a novel set of transcriptional signatures that were designed to resist interference from the cellular heterogeneity of tumors. Tumor mutational load and estimates of tumor purity were included in our association models to adjust for biases in multi-modal genomic data. Copy number alterations, mutations summarized at the gene level, and position-specific mutations were evaluated for association with tumor immune infiltration. We observed a strong relationship between copy number loss of a large region of chromosome 9p and decreased lymphocyte estimates in melanoma, pancreatic, and head/neck cancers. Mutations in the oncogenes PIK3CA, FGFR3, and RAS/RAF family members, as well as the tumor suppressor TP53, were linked to changes in immune infiltration, usually in restricted tumor types. Associations of specific WNT/beta-catenin pathway genetic changes with immune state were limited, but we noted a link between 9p loss and the expression of the WNT receptor FZD3, suggesting that there are interactions between 9p alteration and WNT pathways. Finally, two different cell death regulators, CASP8 and DIDO1, were often mutated in head/neck tumors that had higher lymphocyte infiltrates. In summary, our study supports the relevance of tumor genetics to questions of efficacy and resistance in checkpoint blockade therapies. It also highlights the need to assess genome-wide influences during exploration of any specific tumor pathway hypothesized to be relevant to therapeutic response. Some of the observed genetic links to immune state, like 9p loss, may influence response to cancer immune therapies. Others, like mutations in cell death pathways, may help guide combination therapeutic approaches.
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Using the linear Poisson-Nernst-Planck impedance-response continuum model, we investigate the possible equivalences of three different types of boundary conditions previously proposed to model the ...electrode behavior of an electrolytic cell in the shape of a slab. We show analytically that the boundary conditions proposed long ago by Chang-Jaffe are fully equivalent to the ohmic boundary conditions only if the positive and negative ions have the same mobility, or when only ions of a single polarity are mobile. In the case where the ions have different and non-zero mobilities, we fit exact impedance spectra created for ohmic boundary conditions by using the Chang-Jaffe Poisson-Nernst-Planck response model, one that is dominated by diffusion effects. These fits yield conditions for essentially exact or approximate numerical correspondence for the complex impedance between the two models even in the unequal mobility case. Finally, diffusion type boundary conditions are shown to be fully equivalent to the ohmic one. Some limiting cases of the model parameters are investigated.
People communicate using verbal and non-verbal cues, including gaze cues. Gaze allocation can be influenced by social factors; however, most research on gaze cueing has not considered these factors. ...The presence of social roles was manipulated in a natural, everyday collaborative task while eye movements were measured. In pairs, participants worked together to make a cake. Half of the pairs were given roles (“Chef” or “Gatherer”) and the other half were not. Across all participants we found, contrary to the results of static-image experiments, that participants spent very little time looking at each other, challenging the generalisability of the conclusions from lab-based paradigms. However, participants were more likely than not to look at their partner when receiving an instruction, highlighting the typical coordination of gaze cues and verbal communication in natural interactions. The mean duration of instances in which the partners looked at each other (partner gaze) was longer in the roles condition, and these participants were quicker to align their gaze with their partners (shared gaze). In addition, we found some indication that when hearing spoken instructions, listeners in the roles condition looked at the speaker more than listeners in the no roles condition. We conclude that social context can affect our gaze behaviour during a social interaction.
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Consequences of the well-known Poisson-Nernst-Planck (PNP) continuum equations of charge motion in liquids or solids for ordinary or anomalous diffusion are investigated for an electrochemical cell ...with completely blocking electrodes. Previous work is summarized and much of it is shown to be independent of earlier published results and incomplete, with little comparison made between ordinary and anomalous diffusion. Such comparison is provided here and also includes variation of the mobility ratio of the mobilities of positive and negative charges from equality to charge of only one sign mobile. New generation-recombination effects are demonstrated for a range of mobility ratios, with particular attention given to those present for the case of charge of only one sign mobile. No previous analyses of experimental data with PNP models using complex-least-squares fitting have been published. Here such a model is found to fit frequency response data well for a hydrogel and to lead to estimates of physically meaningful parameters such as the diffusion constant and ionic concentration. PNP analysis of a synthetic data set derived from experimental results for liquid electrolytes refutes claims made in the original publication dealing with it, but verifies and extends an interesting analysis equation proposed there. PNP fitting of data for solids, including ones showing colossal low-frequency-limiting dielectric constants, suggests that they may often be well described as arising from simple diffuse-charge double-layer effects, and that continuum microscopic models such as the PNP, in series with a conducting Debye response model, may be sufficient for fitting well an appreciable amount of data involving ion hopping and trapping behavior.
Obsessive-compulsive disorder (OCD) is a debilitating mental health disorder characterized by intrusive thoughts (obsessions) and repetitive behaviors (compulsions). Dysbiosis, an imbalance in the ...gut microbial composition, has been associated with various health conditions, including mental health disorders, autism, and inflammatory diseases. While the exact mechanisms underlying OCD remain unclear, this review presents a growing body of evidence suggesting a potential link between dysbiosis and the multifaceted etiology of OCD, interacting with genetic, neurobiological, immunological, and environmental factors. This review highlights the emerging evidence implicating the gut microbiota in the pathophysiology of OCD and its potential as a target for novel therapeutic approaches. We propose a model that positions dysbiosis as the central unifying element in the neurochemical, immunological, genetic, and environmental factors leading to OCD. The potential and challenges of microbial reprogramming strategies, such as probiotics and fecal transplants in OCD therapeutics, are discussed. This review raises awareness of the importance of adopting a holistic approach that considers the interplay between the gut and the brain to develop interventions that account for the multifaceted nature of OCD and contribute to the advancement of more personalized approaches.
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Systematic studies of cancer genomes have provided unprecedented insights into the molecular nature of cancer. Using this information to guide the development and application of therapies in the ...clinic is challenging. Here, we report how cancer-driven alterations identified in 11,289 tumors from 29 tissues (integrating somatic mutations, copy number alterations, DNA methylation, and gene expression) can be mapped onto 1,001 molecularly annotated human cancer cell lines and correlated with sensitivity to 265 drugs. We find that cell lines faithfully recapitulate oncogenic alterations identified in tumors, find that many of these associate with drug sensitivity/resistance, and highlight the importance of tissue lineage in mediating drug response. Logic-based modeling uncovers combinations of alterations that sensitize to drugs, while machine learning demonstrates the relative importance of different data types in predicting drug response. Our analysis and datasets are rich resources to link genotypes with cellular phenotypes and to identify therapeutic options for selected cancer sub-populations.
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•We integrate heterogeneous molecular data of 11,289 tumors and 1,001 cell lines•We measure the response of 1,001 cancer cell lines to 265 anti-cancer drugs•We uncover numerous oncogenic aberrations that sensitize to an anti-cancer drug•Our study forms a resource to identify therapeutic options for cancer sub-populations
A look at the pharmacogenomic landscape of 1,001 human cancer cell lines points to new treatment applications for hundreds of known anti-cancer drugs.
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Several important ambiguities in immittance spectroscopy (IS) model data-fitting results are identified and illustrated by means of complex-nonlinear-least-squares (CNLS) fits of experimental and ...synthetic frequency response data. A well-known intrinsic ambiguity, following from Maxwell's electromagnetic equations, arises from the indistinguishability in external measurements of conduction and displacement currents. Usual fit models for either dielectric or conductive-system situations, such as the Davidson-Cole one, only involve a strength parameter, a dielectric constant, a characteristic relaxation time, and a fractional exponent and lead to no additional ambiguities. But the situation is different for more powerful and useful general models, such as ordinary or anomalous diffusion Poisson-Nernst-Planck ones: PNP and PNPA, used here, whose historical background, current status, and applicability are described and discussed herein. They apply to two different kinds of experimental IS situations and involve several additional, potentially free fit parameters, such as the mobilities of positive and negative charge carriers, and generation-recombination parameters that determine the partial or complete dissociation of a neutral entity of concentration N0 into positive and negative charge carriers of equal concentration, c0. Then, several additional ambiguities appear that may require information about the material system involved for their adequate resolution.
Impedance Spectroscopy Barsoukov, Evgenij; Macdonald, J. Ross
2018, 2018-03-19, 2018-03-22
eBook
This book enables understanding of impedance spectroscopy in general and gives detailed guidance to its application in various areas. It covers all the subjects needed by a researcher in order to ...decide whether impedance spectroscopy is useful for a given experiment. It includes theoretical considerations for modeling as well as information on actually applying the technique. Various chapters discuss best measurement methods and identify sources of error. For most investigated subjects the theoretical considerations for the modeling, equivalent circuits and equations in the complex domain are provided. The 3rd edition updates the book to include the results of the last decade of research and adds new areas where impedance spectroscopy has gained importance. Most refreshed are the chapters on electrochemical power sources, supercapacitors, and photochromic materials. The chapter on commercially available measurements systems is updated to keep with the competition between different systems offers available since impedance spectroscopy as a mainstream research tool. New chapters cover the application of impedance spectroscopy to viscoelastic rubbery materials and biological systems.
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