Measurement and Modeling of Gastrointestinal Bioelectric and Biomagnetic Fields PDF Download

Author: Leonard Alan Bradshaw
Publisher:
ISBN:
Category : Biomagnetism
Languages : en
Pages : 604

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Author: Cheryl J. Aine
Publisher: Springer Science & Business Media
ISBN: 146121260X
Category : Science
Languages : en
Pages : 1218

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Book Description
A modified Linear Estimation Approach was performed to reconstruct current sources within the heart. Based on MRI data sets the Boundary Element Method was used to create tailored multicompartment models of the human thorax which were used to solve the forward problem of magnetocardiography. The ability of the proposed method was demonstrated for the localization of a single current dipole as an example of a focal source. By means of introducing small shiftings to all reconstruction dipoles during linear estimation solution as well as performing a successive focussing strategy ignoring places without significant electrical activity the method could easily be extended to the reconstruction of real 3D sources. Based on a special minimum-norm solution the source volume can be estimated applying a finite element approximation using cube elements. The size of an extended current source can be estimated by superimposing the reconstructed dipoles to an equivalent dipole and comparing the corresponding volume with the sphere which would be related to the equivalent dipole. The deviation of these volumes can be taken as a criterion for non-dipolarity of sources.

Author: John Clarke
Publisher: John Wiley & Sons
ISBN: 3527609504
Category : Science
Languages : en
Pages : 653

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Book Description
This two-volume handbook offers a comprehensive and coordinated presentation of SQUIDs (Superconducting Quantum Interference Devices), including device fundamentals, design, technology, system construction and multiple applications. It is intended to bridge the gap between fundamentals and applications, and will be a valuable textbook reference for graduate students and for professionals engaged in SQUID research and engineering. It will also be of use to specialists in multiple fields of practical SQUID applications, from human brain research and heart diagnostics to airplane and nuclear plant testing to prospecting for oil, minerals and buried ordnance. While the first volume presents the theory and fabrication of SQUIDs, the second volume is devoted to applications. It starts with an important aspect of the analysis of measured magnetic signals generated by current sources (the inverse problem), and includes several chapters devoted to various areas of application, namely biomagnetism (research on and diagnostics of human brain, heart, liver, etc.), detection of extremely weak signals, for example electromagnetic radiation and Nuclear Magnetic Resonance. The volume closes with a chapter on motion detectors and the detection of gravity waves.

Author: H. Weinstock
Publisher: Springer Science & Business Media
ISBN: 9401156743
Category : Technology & Engineering
Languages : en
Pages : 716

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Book Description
This book willbcof value to anyone who wishes to consider the use of SQUID-based magnetic sensing for anyone of a number of practical applications. The focus here is to examine in detail how SQUID technology is used and how. the results of the measurements obtained can be interpreted to provide useful information in a variety of real-world applications. The concentration is on those areas that have received the most attention, namely bioma~etism and nondestructive evaluation, but. the topics chosen include as well, geophysics, underwater ordnance detection, accelerometry and a few somewhat more exotic applications. To provide a reasonable perspective. an attempt has been made to consider competing technologies for most applications, and in some cases to consider how SQUID-based technology may be integrated with other technologies to provide an optimum total-system configuration. It is also the intention of the editor, that this book will be of major value to those scientists and engineers who will be required to build both the essential components and complete cryogenic SQUID systems which will be utilized in the various applications presented. Thus, there is a comprehensive review of the principles of SQUID operation, and a detailed exposition on the fabrication of high-temperature-superconducting (HTS) SQUIDs. Although the market is currently dominated by low-temperature superconducting (L TS) SQUIDs, it is reasonably certain that in the near future HTS SQUIDs will take over in most situations.

Author: Jaakko Malmivuo
Publisher: Oxford University Press, USA
ISBN: 9780195058239
Category : Medical
Languages : en
Pages : 512

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Book Description
This text applies engineering science and technology to biological cells and tissues that are electrically conducting and excitable. It describes the theory and a wide range of applications in both electric and magnetic fields.

Author:
Publisher:
ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 896

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Author: L. K. Cheng
Publisher: Springer Science & Business Media
ISBN: 9400765614
Category : Medical
Languages : en
Pages : 266

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Book Description
Research into gastrointestinal motility has received renewed interest in part due to recent advances in the techniques for measuring the structure and function of gastrointestinal cells, tissue and organs. The integration of this wealth of data into biophysically based computation models can aid in interpretation of experimental and clinical measurements and the refinement of measurement techniques. The contents of this book span multiple scales - from cell, tissue, organ, to whole body and is divided into four broad sections covering: i) gastrointestinal cellular activity and tissue structure; (ii) techniques for measuring, analyzing and visualizing high-resolution extra-cellular recordings; (iii) methods for sensing gastroelectrical activity using non-invasive bio-electro-magnetic fields and for modulating the underlying gastric electrical activity and finally (iv) methods for assessing manometric and videographic motility patterns and the application of these data for predicting the flow and mixing behavior of luminal contents by using computational fluid dynamic techniques. This book aims to provide both an overview of historical and existing research techniques as well as to highlight future directions and challenges for the community as a whole. It will be suitable for clinicians to understand the cellular and biophysical underpinnings of gastric emptying, gastroenterologists, surgeons, bioengineers and all scientists with interests in gastrointestinal motility research.

Author: Douglas Cheyne
Publisher:
ISBN:
Category : Medical
Languages : en
Pages : 830

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Book Description
NEW FRONTIERS IN BIOMAGNETISM contains selected papers based on presentations at the 15th International Conference on Biomagnetism (Biomag 2006), held in Vancouver between the 20th and 26th of August, 2006. The conference brought together over 500 scientists and specialists from around the world to present the latest scientific and technological developments in the field of Biomagnetism - the measurement of magnetic signals produced by electric currents in the human body. The study of the minute magnetic fields resulting from heart and muscle contraction, signal conduction in the nervous system, or by the magnetization of biological tissue has grown steadily since the 5th World Conference on Biomagnetism that was held in Vancouver in August of 1984.Although the conference covered many facets of biomagnetism research, the focus for this year's conference was on new frontiers in biomagnetism - the development of new applications and areas of research. One emphasis was on the application of Magnetoencephalography (MEG) to the study of human development and its potential to help understand the physiological underpinnings of language and cognitive development in children, including neurodevelopmental disorders, such as Down Syndrome, autism and language impairment. There were also many exciting contributions on the latest techniques for the precise localization of brain activity using MEG, and related methods for the study of brain dynamics and distributed networks of neural activity. These novel approaches to the study of human brain function promise to provide new insights into the organization of neural systems underlying motor planning, perception, memory and cognition. Other areas of rapid development discussed in New Frontiers in Biomagnetism include the application of biomagnetic measures in the diagnosis and treatment of epilepsy, psychiatric disorders such as schizophrenia, and the use of MEG for presurgical functional mapping. Special sessions were also dedicated to the latest developments in Magnetocardiography (MCG) for the assessment of cardiovascular disease and associated disorders of the electrical activity of the heart. This year's conference also held a special symposium in honour of the late Sam Williamson, with presentations from his former colleagues and students that reviewed his life's work and contributions to the field of neuromagnetism. NEW FRONTIERS IN BIOMAGNETISM aims to provide a comprehensive overview of the latest developments in the field of Biomagnetism and its application to the study of human biological systems. The many new developments and breakthroughs presented at Biomag 2006 made a significant contribution to the advancement of the understanding of brain and cardiac function and provided new tools for clinical applications of this new knowledge.

Author: Gregory O'Grady
Publisher: Gregory O'Grady
ISBN:
Category :
Languages : en
Pages : 373

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Book Description
Gastric motility disorders remain a complex clinical challenge, and inflict a substantial burden of cost and suffering on society. Gastric contractions are coordinated by an underlying electrical activity, and gastric dysrhythmias are implicated in the pathophysiology of several motility disorders. However, the significance of dysrhythmias remains uncertain, and there are few elective therapies, because current tools to investigate dysrhythmias have low reliability owing to their lack of spatial resolution. This thesis aimed to develop an improved foundation for the investigation and management of gastric dysrhythmia, by advancing and translating high-resolution (HR; multi-electrode) spatiotemporal mapping. The research is a cross-disciplinary program of bioengineering, and basic and clinical electrophysiology. A range of HR mapping devices are first developed and validated for intra-operative gastric mapping, including at open and laparoscopic surgery. Automated signal processing tools are next validated for the efficient, reliable marking, grouping, and mapping of slow wave events, and these tools are integrated into an intuitive software platform. These methodological advances are then applied in a series of experimental studies. The origin and propagation of porcine gastric slow wave activity is defined, followed by clinical translation with the first spatiotemporal analysis of normal human gastric slow wave propagation. The methods are then applied to define new patterns and mechanisms of gastric dysrhythmia, initially in a porcine model, including the first demonstration of how rapid, high-amplitude circumferential propagation emerges during dysrhythmias. The first clinical study applying HR electrical mapping is then presented, performed on a cohort of patients with diabetic and idiopathic gastroparesis, revealing new patterns of human dysrhythmia. A new classification scheme for abnormalities of human gastric slow wave initiation and conduction is proposed. Finally, the evidence for high-frequency gastric electrical stimulation is reviewed, prior to the presentation of a new 'entrainment mapping' method for better assessing gastric pacing protocols. In total, this work constitutes a coordinated series of advances that offer a strengthened foundation for investigating and managing gastric electrical abnormalities. It is hoped that these new methods and findings will translate into future clinical advances, to improve the diagnosis and treatment of these complex patient populations.

Author: Kwang-Sup Soh
Publisher: Springer Science & Business Media
ISBN: 1461406013
Category : Medical
Languages : en
Pages : 327

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Proceedings from the first International Symposium on Primo Vascular System 2010 (ISPS 2010) with special topics on cancer and regeneration was held in Jecheon, Korea during September 17-18, 2010. Includes coverage of new study results that have better revealed the functional aspects of PVS, including its roles in the areas of regenerative medicine and cancer.