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Register a new userWhack-A-Mole Model: Towards unified description of biological effect caused by radiation-exposure
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We present a novel model to estimate biological effects caused by artificial radiation exposure, Whack-a-mole (WAM) model. It is important to take account of the recovery effects during the time course of the cellular reactions. The inclusion of the dose-rate dependence is essential in the risk estimation of low dose radiation, while nearly all the existing theoretical models relies on the total dose dependence only. By analyzing the experimental data of the relation between the radiation dose and the induced mutation frequency of 5 organisms, mouse, drosophila, chrysanthemum, maize and tradescantia, we found that all the data can be reproduced by WAM model. Most remarkably, a scaling function, which is derived from WAM model, consistently accounts for the observed mutation frequencies of 5 organisms. This is the first rationale to account for the dose rate dependence as well as to give a unified understanding of a general feature of organisms.
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Understanding metallic behaviour is still one of the central tasks in Condensed Matter Physics. Recent developments have energized the interest in several modern concepts, such as strange metal, bad metal, and Planckian metal. However, a unified description of metallic resistivity applicable to the existing diversity of materials is still missing. Herein we present an empirical analysis of a large variety of metals, from normal metals to strongly correlated metals, using the same phenomenological approach. The electrical resistivity in all the cases follows a parallel resistor formalism, which takes both T-linear and T-quadratic dependence of the scattering rates into account. The results reveal the significance of the model by showing that the different metallic classes are determined by the relative magnitude of these two components. Importantly, our analysis shows that the T-linear term arises from the Planckian dissipation limit and it is present in all considered systems. This formalism extends previous reports on strange and normal metals, facilitating the classification of materials with non-linear resistivity curves, an important step towards the experimental confirmation of the universal character of the Planckian dissipation bound.
We develop a kinetic reaction model for cells having irradiated DNA molecules due to ionizing radiation exposure. Our theory simultaneously accounts for the time-dependent reactions of the DNA damage, the DNA mutation, the DNA repair, and the proliferation and apoptosis of cells in a tissue with a minimal set of model parameters. In contrast to existing theories for radiation exposition, we do not assume the relationships between the total dose and the induced mutation frequency. Our theory provides a universal scaling function that reasonably explains the mega-mouse experiments in Ref.[W. L. Russell and E. M. Kelly, Proc. Natl. Acad. Sci. USA. {bf 79} (1982) 542.] with different dose rates. Furthermore, we have estimated the effective dose rate, which is biologically equivalent to the ionizing effects other than those caused by artificial irradiation. This value is $ 1.11 times 10^{-3} ~rm{[Gy/hr]}$, which is significantly larger than the effect caused by natural background radiation.
Since their discovery in 1896, x-rays have had a profound impact on science, medicine and technology. Here we show that the x-rays from a novel tabletop source of bright coherent synchrotron radiation can be applied to phase contrast imaging of biological specimens, yielding superior image quality and avoiding the need for scarce or expensive conventional sources.
Analysis of transverse momentum distributions is a useful tool to understand the dynamics of relativistic particles produced in high energy collision. Finding a proper distribution function to approximate the spectra is a vastly developing area of research in particle physics. In this work, we have provided a detailed theoretical description of the application of the unified statistical framework in high energy physics. Here, the transverse momentum spectra of pion measured by experiment at RHIC and LHC are also investigated in the framework of relativistic statistical thermodynamics using unified distribution.
A first principles approach to the theoretical description of the development of biological forms, from a fertilized egg to a functioning embryo, remains a central challenge to applied physics and theoretical biology. Rather than refer to principles of self-organization and non-equilibrium statistical mechanics to describe a developing embryo from its active cellular constituents, a purely geometric theory is constructed that references the properties of the ambient space that the embryo occupies. In 1975 the Fields laureate Ren{e} Thom developed a system of techniques and local dynamical models that are capable of reconstructing the local dynamic of an embryo at each new growth event of the system. Each new growth event (the development of a limb, for example) is a topological change in the dynamic of the system that can be classified only according to the properties of space. The local models can be non-conservative flows with robust attractor behavior that serve as organizing centers for systems development. Hamiltonian flows can also be considered with novel, self-reproducing vague attractor behavior. The set of growth events become an unfolding space related to the differentiable manifold of states. The set of growth events, which Thom refers to as the catastrophe set, has special algebraic properties which permit these models to be low dimensional--the local model contains few parameters. We present Thoms work as a research program outlining a framework for the construction of these local models, and, ultimately, the synthesis of these models into a full theoretical description of a developing biological organism. We give examples of the application of selected models to key growth events in the process of gastrulation.
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