Search results: Found 29

Listing 1 - 10 of 29 << page
of 3
>>
Sort by
Seismic Wave Propagation in Stratified Media

Author:
ISBN: 9781921536731 Year: Pages: 288 DOI: 10.26530/OAPEN_459524 Language: English
Publisher: ANU Press
Subject: Geology --- Earth Sciences
Added to DOAB on : 2012-06-14 11:46:24
License: ANU Press

Loading...
Export citation

Choose an application

Abstract

Seismic Wave Propagation in Stratified Media presents a systematic treatment of the interaction of seismic waves with Earth structure. The theoretical development is physically based and is closely tied to the nature of the seismograms observed across a wide range of distance scales – from a few kilometres as in shallow reflection work for geophysical prospecting, to many thousands of kilometres for major earthquakes. A unified framework is presented for all classes of seismic phenomena, for both body waves and surface waves. Since its first publication in 1983 this book has been an important resource for understanding the way in which seismic waves can be understood in terms of reflection and transmission properties of Earth models, and how complete theoretical seismograms can be calculated. The methods allow the development of specific approximations that allow concentration on different seismic arrivals and hence provide a direct tie to seismic observations.

Detection and characterization of inclusions in impedance tomography

Author:
ISBN: 9783866446359 Year: Pages: VIII, 135 p. DOI: 10.5445/KSP/1000021838 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Computer Science
Added to DOAB on : 2019-07-30 20:01:57
License:

Loading...
Export citation

Choose an application

Abstract

The topic of this work are two further developments of the Factorization method for electrical impedance tomography.We present a modification of this method that is capable of detecting mixed inclusions, i.e. both inclusions with a higher as well as inclusions with a lower conductivity than the background medium. In addition, we derive a new method to compute the conductivity inside inclusions after they have been localized.

In Vivo Imaging in Pharmacological Research

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452378 Year: Pages: 222 DOI: 10.3389/978-2-88945-237-8 Language: English
Publisher: Frontiers Media SA
Subject: Therapeutics --- Science (General)
Added to DOAB on : 2017-10-13 14:57:01
License:

Loading...
Export citation

Choose an application

Abstract

The discovery and development of a biological active molecule with therapeutic properties is an ever increasing complex task, highly unpredictable at the early stages and marked, in the end, by high rates of failure. As a consequence, the overall process leading to the production of a successful drug is very costly. The improvement of the net outcome in drug discovery and development would require, amongst other important factors, a good understanding of the molecular events that characterize the disease or pathology in order to better identify likely targets of interest, to optimize the interaction of an active agent (small molecule or macromolecule of natural or synthetic origin) with those targets, and to facilitate the study of the pharmacokinetics, pharmacodynamics and toxicity of an active agent in suitable models and in human subjects. The objective of this Research Topic is to highlight new developments and applications of imaging techniques with the objective of performing pharmacological studies in vivo, in animal models and in humans. In the domain of drug discovery, the pharmacological and biomedical questions constitute the center of attention. In this sense, it is fundamental to keep in mind the strengths and limitations of each analytical or imaging technique. At the end, the judicious application of the technique with the aim of supporting the search for answers to manifold questions arising during a long and painstaking path provides a continuous role for imaging within the complex area of drug discovery and development.

Development and Application of Optical Coherence Tomography (Oct)

Author:
ISBN: 9783038427445 9783038427438 Year: Pages: 212 DOI: 10.3390/books978-3-03842-743-8 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering
Added to DOAB on : 2018-02-16 08:34:07
License:

Loading...
Export citation

Choose an application

Abstract

This special feature issue has been initiated to celebrate the 25th anniversary of Optical Coherence Tomography (OCT). In OCT, broad bandwidth light is used in order to produce cross sectional images of turbid and translucent samples with high axial resolution (in the order of a few µm). The imaging speed of OCT can be as high as several millions of depth scans (A-scans) per second which allows for various applications in different fields. This special feature issue consists of three overview papers covering OCT angiography, polarization-sensitive OCT and dental applications of OCT. Additional applications and the latest developments in OCT are covered in nine research papers. The latest developments presented in this issue include magnetomotive OCT, resonant Doppler OCT, full field OCT, new segmentation algorithms and depth range extension. Applications of OCT are widely spread and range from quality control in tooth prostheses and coating thickness measurements in the automotive industry to the assessment of degradation of coatings and alveolar dynamics.

Monitoring the water content evolution of dikes

Author:
Book Series: Wissenschaftliche Berichte des Instituts für Meteorologie und Klimaforschung der Universität Karlsruhe (TH) ISSN: 01795619 ISBN: 9783866443211 Year: Volume: 44 Pages: 147 p. DOI: 10.5445/KSP/1000009929 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Astronomy (General)
Added to DOAB on : 2019-07-30 20:01:59
License:

Loading...
Export citation

Choose an application

Abstract

The water content evolution of model dikes is monitored with geophysical methods. Water content changes are successfully quantified using electrical resistivity tomography. Numerical simulation of water flow in a dike model is used to estimate the variability of water content. Modeling of synthetic data sets is used to evaluate the quality of resistivity quantification using ERT. An ensemble approach is proposed to improve the interpretation of ERT inversions.

The Ischemic Penumbra: Still the Target for Stroke Therapies?

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196357 Year: Pages: 69 DOI: 10.3389/978-2-88919-635-7 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Neurology
Added to DOAB on : 2016-08-16 10:34:25
License:

Loading...
Export citation

Choose an application

Abstract

The ischemic penumbra was initially defined by Symon, Lassen and colleagues in the 1970s as an area of brain tissue with inadequate blood flow to maintain electric activity of neurons but adequate blood flow to preserve the function of the ion channels. This area of tissue, receiving enough blood to survive but not enough to function, often surrounds or abuts the irreversibly damaged core in ischemic stroke. It was shown that if blood flow could be restored to this area of marginal perfusion, the tissue could survive and function again, and growth of the core could be prevented. Based on seminal PET studies, penumbra or "penumbral tissue" eventually took on a subtly different meaning - the area of brain that is destined to progress to infarct unless blood flow is restored within a particular time window. The penumbra thus became the target for all acute stroke interventions - to preserve viability of the tissue and restore function. New imaging techniques, including diffusion and perfusion MRI and CT perfusion, were developed to rapidly identify individuals with penumbra, who were thought to be the best candidates for aggressive interventions to restore blood flow, particularly beyond the licensed time-window for IV thrombolysis. However, most clinical trials have failed to establish the usefulness of identifying candidates for treatment in this way using pre-specified protocols and primary endpoints. These trials have used different and sometimes unvalidated thresholds of hypoperfusion as well as irreversible infarct and various definitions of significant penumbra (or mismatch between irreversible infarct and hypoperfused, but salvageable tissue), and reanalysis of their data using more refined image processing showed post-hoc positivity. They have also evaluated outcome in a variety of ways, with few studies measuring the direct effect of restoring blood flow on the function of the penumbral tissue. Therefore, important remaining questions include how to define, characterize, and image the penumbra in acute stroke to achieve the greatest reliability and validity for what we want to measure, and whether this concept, so defined, provides an optimal target for stroke therapy using state-of-the-art trial design.

The Chemistry of Imaging Probes

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889455980 Year: Pages: 129 DOI: 10.3389/978-2-88945-598-0 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Chemistry (General)
Added to DOAB on : 2019-01-23 14:53:43
License:

Loading...
Export citation

Choose an application

Abstract

Over the past decades, the field of molecular imaging has been rapidly growing involving multiple disciplines such as medicine, biology, chemistry, pharmacology and biomedical engineering. Any molecular imaging procedure requires an imaging probe that is an agent used to visualize, characterize and quantify biological processes in living systems. Such a probe typically consists of an agent that usually produces signal for imaging purpose, a targeting moiety, and a linker connecting the targeting moiety and the signaling agent.Many challenging problems of molecular imaging can be addressed by exploiting the great possibilities offered by modern synthetic organic and coordination chemistry and the powerful procedures provided by conjugation chemistry. Thus, chemistry plays a decisive role in the development of this cutting-edge methodology.Currently, the diagnostic imaging modalities include Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Ultrasound (US), Nuclear Imaging (PET, SPECT), Optical Imaging (OI) and Photoacoustic Imaging (PAI). Each of these imaging modalities has its own advantages and disadvantages, and therefore, a multimodal approach combining two techniques is often adopted to generate complementary anatomical and functional information of the disease. The basis for designing imaging probes for a given application is dictated by the chosen imaging modality, which in turn is dependent upon the concentration and localization profile (vascular, extracellular matrix, cell membrane, intracellular, near or at the cell nucleus) of the target molecule. The development of high-affinity ligands and their conjugation to the targeting vector is also one of the key steps for pursuing efficient molecular imaging probes. Other excellent reviews, text and monographs describe the principles of biomedical imaging, focusing on molecular biology or on the physics behind the techniques. This Research Topic aims to show how chemistry can offer molecular imaging the opportunity to express all its potential.

Optical Methods in Sensing and Imaging for Medical and Biological Applications

Authors: --- ---
ISBN: 9783038973706 / 9783038973713 Year: Pages: 288 DOI: 10.3390/books978-3-03897-371-3 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering --- Medicine (General) --- Therapeutics
Added to DOAB on : 2019-01-24 12:31:31
License:

Loading...
Export citation

Choose an application

Abstract

The recent advances in optical sources and detectors have opened up new opportunities for sensing and imaging techniques which can be successfully used in biomedical and healthcare applications. This book, entitled ‘Optical Methods in Sensing and Imaging for Medical and Biological Applications’, focuses on various aspects of the research and development related to these areas. The book will be a valuable source of information presenting the recent advances in optical methods and novel techniques, as well as their applications in the fields of biomedicine and healthcare, to anyone interested in this subject.

Image-Guided Radiotherapy for Effective Radiotherapy Delivery

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198498 Year: Pages: 111 DOI: 10.3389/978-2-88919-849-8 Language: English
Publisher: Frontiers Media SA
Subject: Oncology --- Medicine (General)
Added to DOAB on : 2016-01-19 14:05:46
License:

Loading...
Export citation

Choose an application

Abstract

Image-guided radiotherapy (IGRT) is a new radiotherapy technology that combines the rapid dose fall off associated with intensity-modulated radiotherapy (IMRT) and daily tumor imaging allowing for high precision tumor dose delivery and effective sparing of surrounding normal organs. The new radiation technology requires close collaboration between radiologists, nuclear medicine specialists, and radiation oncologists to avoid marginal miss. Modern diagnostic imaging such as positron emission tomography (PET) scans, positron emission tomography with Computed Tomograpgy (PET-CT), and magnetic resonance imaging (MRI) allows the radiation oncologist to target the positive tumor with high accuracy. As the tumor is well visualized during radiation treatment, the margins required to avoid geographic miss can be safely reduced , thus sparing the normal organs from excessive radiation. When the tumor is located close to critical radiosensitive structures such as the spinal cord, IGRT can deliver a high dose of radiation to the tumor and simultaneously decreasing treatment toxicity, thus potentially improving cure rates and patient quality of life. During radiotherapy, tumor shrinkage and changes of normal tissues/volumes can be detected daily with IGRT. The volume changes in the target volumes and organs at risk often lead to increased radiation dose to the normal tissues and if left uncorrected may result in late complications. Adaptive radiotherapy with re-planning during the course of radiotherapy is therefore another advantage of IGRT over the conventional radiotherapy techniques. This new technology of radiotherapy delivery provides the radiation oncologist an effective tool to improve patient quality of life. In the future, radiation dose-escalation to the residual tumor may potentially improve survival rates. Because the treatment complexity, a great deal of work is required from the dosimetry staff and physicists to ensure quality of care. Preliminary clinical results with IGRT are encouraging but more prospective studies should be performed in the future to assess the effectiveness of IGRT in improving patient quality of life and local control. In this Frontiers Research Topic, we encourage submission of original papers and reviews dealing with imaging for radiotherapy planning, the physics and dosimetry associated with IGRT, as well as the clinical outcomes for cancer treatment with IGRT for all tumor sites.

Pathophysiology and Imaging Diagnosis of Demyelinating Disorders

Author:
ISBN: 9783038429432 9783038429449 Year: Pages: X, 168 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Neurology
Added to DOAB on : 2018-06-27 15:51:32
License:

Loading...
Export citation

Choose an application

Abstract

Demyelinating disorders are chronic autoimmune disorders characterized by inflammation, demyelination, axonal degeneration, and neuronal loss. They have complex pathophysiology and diverse clinical presentations. The etiology of these disorders lies in the interaction between genetic and environmental factors. Due to the complexity in pathophysiology and presentation, diagnosis and treatment can be challenging. Advanced technology, including modern imaging techniques, as well as optical coherence tomography (OCT), enrich our understanding of the disease process, improve diagnostic accuracy, and may guide treatment decisions.

Listing 1 - 10 of 29 << page
of 3
>>
Sort by
Narrow your search