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Zeitschrift Fur Medizinische Physik Feb 2022
Topics: Physics
PubMed: 35094915
DOI: 10.1016/j.zemedi.2022.01.002 -
Progress in Biophysics and Molecular... Oct 2016Theories organize knowledge and construct objectivity by framing observations and experiments. The elaboration of theoretical principles is examined in the light of the... (Review)
Review
Theories organize knowledge and construct objectivity by framing observations and experiments. The elaboration of theoretical principles is examined in the light of the rich interactions between physics and mathematics. These two disciplines share common principles of construction of concepts and of the proper objects of inquiry. Theory construction in physics relies on mathematical symmetries that preserve the key invariants observed and proposed by such theory; these invariants buttress the idea that the objects of physics are generic and thus interchangeable and they move along specific trajectories which are uniquely determined, in classical and relativistic physics. In contrast to physics, biology is a historical science that centers on the changes that organisms experience while undergoing ontogenesis and phylogenesis. Biological objects, namely organisms, are not generic but specific; they are individuals. The incessant changes they undergo represent the breaking of symmetries, and thus the opposite of symmetry conservation, a central component of physical theories. This instability corresponds to the changes of the environment and the phenotypes. Inspired by Galileo's principle of inertia, the "default state" of inert matter, we propose a "default state" for biological dynamics following Darwin's first principle, "descent with modification" that we transform into "proliferation with variation and motility" as a property that spans life, including cells in an organism. These dissimilarities between theories of the inert and of biology also apply to causality: biological causality is to be understood in relation to the distinctive role that constraints assume in this discipline. Consequently, the notion of cause will be reframed in a context where constraints to activity are seen as the core component of biological analyses. Finally, we assert that the radical materiality of life rules out distinctions such as "software vs. hardware."
Topics: Animals; Biology; Humans; Mathematics; Physics
PubMed: 27390105
DOI: 10.1016/j.pbiomolbio.2016.06.005 -
The Ulster Medical Journal Jan 2014
Topics: History, 18th Century; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Periodicals as Topic; Physics; Poetry as Topic; Scotland
PubMed: 24757259
DOI: No ID Found -
Journal of Neurophysiology Mar 2021Magnetoencephalography (MEG) is a technique used to measure the magnetic fields generated from neuronal activity in the brain. MEG has a high temporal resolution on the... (Review)
Review
Magnetoencephalography (MEG) is a technique used to measure the magnetic fields generated from neuronal activity in the brain. MEG has a high temporal resolution on the order of milliseconds and provides a more direct measure of brain activity when compared with hemodynamic-based neuroimaging methods such as magnetic resonance imaging and positron emission tomography. The current review focuses on basic features of MEG such as the instrumentation and the physics that are integral to the signals that can be measured, and the principles of source localization techniques, particularly the physics of beamforming and the techniques that are used to localize the signal of interest. In addition, we review several metrics that can be used to assess functional coupling in MEG and describe the advantages and disadvantages of each approach. Lastly, we discuss the current and future applications of MEG.
Topics: Action Potentials; Animals; Biophysical Phenomena; Brain; Humans; Magnetoencephalography; Neurosciences; Physics
PubMed: 33567968
DOI: 10.1152/jn.00530.2020 -
Advances in Physiology Education Dec 2017We adopted well-known physics equations to illustrate concepts for developing a successful academic career plan. Formulas for distance, force, momentum, and power are...
We adopted well-known physics equations to illustrate concepts for developing a successful academic career plan. Formulas for distance, force, momentum, and power are used to explain how to define goals and set a pace that maximizes success potential. Formulas for synergy, balance, and stress are used to highlight common obstacles encountered by both junior (untenured and early career) and established faculty and provide ways to circumvent or limit damage from setbacks. Combined, these formulas provide tips for thriving in an academic environment.
Topics: Career Mobility; Faculty, Medical; Humans; Physics
PubMed: 28978516
DOI: 10.1152/advan.00105.2017 -
Trends in Cancer Apr 2018
Topics: Biomedical Research; Humans; Medical Oncology; Neoplasms; Physics
PubMed: 29606305
DOI: 10.1016/j.trecan.2018.03.001 -
Nano Letters Oct 2021Organic molecules and specifically bio-organic systems are attractive for applications due to their low cost, variability, environmental friendliness, and facile...
Organic molecules and specifically bio-organic systems are attractive for applications due to their low cost, variability, environmental friendliness, and facile manufacturing in a bottom-up fashion. However, due to their relatively low conductivity, their actual application is very limited. Chiral metallo-bio-organic crystals, on the other hand, have improved conduction and in addition interesting magnetic properties. We developed a spin transistor using these crystals and based on the chiral-induced spin selectivity effect. This device features a memristor type behavior, which depend on trapping both charges and spins. The spin properties are monitored by Hall signal and by an external magnetic field. The spin transistor exhibits nonlinear drain-source currents, with multilevel controlled states generated by the magnetization of the source. Varying the source magnetization enables a six-level readout for the two-terminal device. The simplicity of the device paves the way for its technological application in organic electronics and bioelectronics.
Topics: Electric Conductivity; Electronics; Magnetic Fields; Magnetics; Metals
PubMed: 34662128
DOI: 10.1021/acs.nanolett.1c01865 -
Arhiv Za Higijenu Rada I Toksikologiju Mar 2019This article gives an overview of physical concepts important for radioecology and radiotoxicology to help bridge a gap between non-physicists in these scientific... (Review)
Review
This article gives an overview of physical concepts important for radioecology and radiotoxicology to help bridge a gap between non-physicists in these scientific disciplines and the intricate language of physics. Relying on description and only as much mathematics as necessary, we discuss concepts ranging from fundamental natural forces to applications of physical modelling in phenomenological studies. We first explain why some atomic nuclei are unstable and therefore transmute. Then we address interactions of ionising radiation with matter, which is the foundation of both radioecology and radiotoxicology. We continue with relevant naturally occurring and anthropogenic radionuclides and their properties, abundance in the environment, and toxicity for the humans and biota. Every radioecological or radiotoxicological assessment should take into account combined effects of the biological and physical half-lives of a radionuclide. We also outline the basic principles of physical modelling commonly used to study health effects of exposure to ionising radiation, as it is applicable to every source of radiation but what changes are statistical weighting factors, which depend on the type of radiation and exposed tissue. Typical exposure doses for stochastic and deterministic health effects are discussed, as well as controversies related to the linear no-threshold hypothesis at very low doses.
Topics: Ecotoxicology; Physics; Radiation Monitoring; Radioisotopes; Terminology as Topic
PubMed: 30956222
DOI: 10.2478/aiht-2019-70-3225 -
CBE Life Sciences Education Jun 2013In this editorial we link the articles published in this Special Issue with the framework from Vision and Change and summarize findings from the editorial process of...
In this editorial we link the articles published in this Special Issue with the framework from Vision and Change and summarize findings from the editorial process of assembling the Special Issue.
Topics: Biology; Curriculum; Interdisciplinary Communication; Physics; Research
PubMed: 23737614
DOI: 10.1187/cbe.13-03-0069 -
Nature Oct 2023Scientists have grappled with reconciling biological evolution with the immutable laws of the Universe defined by physics. These laws underpin life's origin, evolution...
Scientists have grappled with reconciling biological evolution with the immutable laws of the Universe defined by physics. These laws underpin life's origin, evolution and the development of human culture and technology, yet they do not predict the emergence of these phenomena. Evolutionary theory explains why some things exist and others do not through the lens of selection. To comprehend how diverse, open-ended forms can emerge from physics without an inherent design blueprint, a new approach to understanding and quantifying selection is necessary. We present assembly theory (AT) as a framework that does not alter the laws of physics, but redefines the concept of an 'object' on which these laws act. AT conceptualizes objects not as point particles, but as entities defined by their possible formation histories. This allows objects to show evidence of selection, within well-defined boundaries of individuals or selected units. We introduce a measure called assembly (A), capturing the degree of causation required to produce a given ensemble of objects. This approach enables us to incorporate novelty generation and selection into the physics of complex objects. It explains how these objects can be characterized through a forward dynamical process considering their assembly. By reimagining the concept of matter within assembly spaces, AT provides a powerful interface between physics and biology. It discloses a new aspect of physics emerging at the chemical scale, whereby history and causal contingency influence what exists.
Topics: Humans; Biological Evolution; Cultural Evolution; Inventions; Models, Theoretical; Origin of Life; Physics; Selection, Genetic; Animals
PubMed: 37794189
DOI: 10.1038/s41586-023-06600-9