441 research outputs found
Electromagnetic induction imaging with atomic magnetometers: Progress and perspectives
Electromagnetic induction imaging (EMI) allows mapping of the conductivity of target objects and, when combined with appropriate algorithms, the generation of full 3D tomographic images. Despite its tremendous potential, and the wealth of possible applications, the use of EMI has essentially been limited to eddy current testing for monitoring of corrosion and welding in metallic structures. The present work reviews the factors hindering the progress of electromagnetic induction imaging and highlights how the use of atomic magnetometers overcame some of them, opening the path to real world applications of EMI. Perspectives for further developments are discussed
Bioimaging and Bio-Sensing Techniques for Lung Cancer Detection
Early cancer detection and suitable treatment improve the 5-year survival rates of lung cancer significantly. Many cancer diagnostic approaches have been investigated, including mammography, magnetic resonance imaging, ultrasound, computerized tomography, positron emission tomography and biopsy. However, these techniques have some drawbacks such as expensive and time-consuming. Electromagnetic tomography (EMT) has been proposed as a promising diagnostic tool for lung cancer detection. In addition, developing label-free and cost-effective biosensors for target tumor markers detection have attracted attentions worldwide. This chapter reviews the recently developed EMT and bio-sensing techniques for early-stage lung cancer detection
Mind as a Virtual Phase-Conjugated Hologram
Because of its superior information processing capability, previous authors have proposed that phase conjugation holography offers a feasible mechanism to explain various aspects of human perception. These previous models focused on the relationship between the perceived image of an object and the actual object with little attention to the anatomical location of the phase-conjugation mirror. The present article proposes that phase-conjugation mirrors exist in the brain as 3D networks of organic molecules previously observed to exhibit phase-conjugation behavior. In particular rhodopsin photoreceptor molecules are proposed to form extra-retinal, deep brain networks which function as phase-conjugation mirrors which are distributed throughout the brain. Furthermore, such networks are proposed to convert endogenous biophotons into virtual holograms which function to store cognitive information in the brain. Such a system offers a new functional definition of the mind
Magnetic Induction Tomography (MIT) simulation study for renal screening using different system frequencies and sizes of calcium oxalate
Nephrolithiasis is the process of forming stone in the kidney by crystallization. Due to the increasing prevalence of nephrolithiasis from time to time, medical institutions look for more advanced technology of medical imaging which can tackle the disadvantages of current medical imaging devices for renal, which are non-invasive, free radiation and rapid use. The research encompassed the design simulation study of Magnetic Induction Tomography (MIT) system for renal screening by using COMSOL multiphysics. MIT is a soft field tomography and a non-contact imaging modality used to image the passive electromagnetic properties (conductivity, permittivity and permeability) by applying principle of electromagnetic induction. In this research, 8 copper trans-receiver coils were employed in the MIT system and fixed by the insulation belt. Meanwhile, geometric set-up of renal organ imitates the transverse section at renal level of human body. Sensor performance analysis of MIT system was done based on various frequency and radius of calcium oxalate inside kidneys. In conclusion, frequency and radius of calcium oxalate affect the sensitivity performance of MIT system and has inverse relationship with sensitivity performance
Aerospace Medicine and Biology. A continuing bibliography with indexes
This bibliography lists 244 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1981. Aerospace medicine and aerobiology topics are included. Listings for physiological factors, astronaut performance, control theory, artificial intelligence, and cybernetics are included
Index to NASA Tech Briefs, 1972
Abstracts of 1972 NASA Tech Briefs are presented. Four indexes are included: subject, personal author, originating center, and Tech Brief number
Index to NASA Tech Briefs, 1975
This index contains abstracts and four indexes--subject, personal author, originating Center, and Tech Brief number--for 1975 Tech Briefs
A study of Magnetic Induction Tomography (MIT) for calcium oxalate renal screening
Nephrolithiasis is a process of stone formation in the kidney by crystallization. The increasing prevalence of nephrolithiasis from time to time had sought an alternative from the conventional imaging techniques that is invasive, radiative, and non-rapid usage. This paper enclosed a design simulation study of Magnetic Induction Tomography (MIT) system using COMSOL Multiphysics for renal imaging. MIT is a soft field tomography and non-contact imaging modality which can project the passive electromagnetic properties (conductivity, permittivity and permeability) under the principle of electromagnetic induction. In this research, 8 copper transreceiver coils were employed in the MIT system and fixed by the insulation belt. Meanwhile, geometric set-up of renal organ was set to imitate the transverse section of human renal. In the methodology, sensor performance analyses were done using frequency ranging from 50 kHz to 2 MHz of the MIT system on radii of calcium oxalate in renal. The sensor response and pattern are discussed in this paper
Coherent methods in the X-ray sciences
X-ray sources are developing rapidly and their coherent output is growing
extremely rapidly. The increased coherent flux from modern X-ray sources is
being matched with an associated rapid development in experimental methods.
This article reviews the literature describing the ideas that utilise the
increased brilliance from modern X-ray sources. It explores how ideas in
coherent X-ray science are leading to developments in other areas, and vice
versa. The article describes measurements of coherence properties and uses this
discussion as a base from which to describe partially-coherent diffraction and
X-ray phase contrast imaging, with its applications in materials science,
engineering and medicine. Coherent diffraction imaging methods are reviewed
along with associated experiments in materials science. Proposals for
experiments to be performed with the new X-ray free-electron-lasers are briefly
discussed. The literature on X-ray photon correlation spectroscopy is described
and the features it has in common with other coherent X-ray methods are
identified. Many of the ideas used in the coherent X-ray literature have their
origins in the optical and electron communities and these connections are
explored. A review of the areas in which ideas from coherent X-ray methods are
contributing to methods for the neutron, electron and optical communities is
presented.Comment: A review articel accepted by Advances in Physics. 158 pages, 29
figures, 3 table
Mechanical Sensing of Living Systems — From Statics to Dynamics
Living systems are fascinating sensing machines that outmatch all artificial machines. Our aim is to put a focus on the dynamics of mechanosensing in cellular systems through concepts and experimental approaches that have been developed during the past decades. By recognizing that a cellular system is not simply the intricate assembly of active and passive macromolecular actors but that it can also manifest scale-invariant and/or highly nonlinear global dynamics, biophysicists have opened a new domain of investigation of living systems. In this chapter, we review methods and techniques that have been implemented to decipher the cascade of temporal events which enable a cell to sense a mechanical stimulus and to elaborate a response to adapt or to counteract this perturbation. We mainly describe intrusive (mechanical probes) and nonintrusive (optical devices) experimental methods that have proved to be efficient for real-time characterization of stationary and nonstationary cellular dynamics. Finally, we discuss whether thermal fluctuations, which are inherent to living systems, are a source of coordination (e.g., synchronization) or randomization of the global dynamics of a cell
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