Quantum physics meets biology.

Science.gov (United States)

Arndt, Markus; Juffmann, Thomas; Vedral, Vlatko

2009-12-01

Quantum physics and biology have long been regarded as unrelated disciplines, describing nature at the inanimate microlevel on the one hand and living species on the other hand. Over the past decades the life sciences have succeeded in providing ever more and refined explanations of macroscopic phenomena that were based on an improved understanding of molecular structures and mechanisms. Simultaneously, quantum physics, originally rooted in a world-view of quantum coherences, entanglement, and other nonclassical effects, has been heading toward systems of increasing complexity. The present perspective article shall serve as a "pedestrian guide" to the growing interconnections between the two fields. We recapitulate the generic and sometimes unintuitive characteristics of quantum physics and point to a number of applications in the life sciences. We discuss our criteria for a future "quantum biology," its current status, recent experimental progress, and also the restrictions that nature imposes on bold extrapolations of quantum theory to macroscopic phenomena.

Physical properties of biological entities: an introduction to the ontology of physics for biology.

Directory of Open Access Journals (Sweden)

Daniel L Cook

Full Text Available As biomedical investigators strive to integrate data and analyses across spatiotemporal scales and biomedical domains, they have recognized the benefits of formalizing languages and terminologies via computational ontologies. Although ontologies for biological entities-molecules, cells, organs-are well-established, there are no principled ontologies of physical properties-energies, volumes, flow rates-of those entities. In this paper, we introduce the Ontology of Physics for Biology (OPB, a reference ontology of classical physics designed for annotating biophysical content of growing repositories of biomedical datasets and analytical models. The OPB's semantic framework, traceable to James Clerk Maxwell, encompasses modern theories of system dynamics and thermodynamics, and is implemented as a computational ontology that references available upper ontologies. In this paper we focus on the OPB classes that are designed for annotating physical properties encoded in biomedical datasets and computational models, and we discuss how the OPB framework will facilitate biomedical knowledge integration.

Physical properties of biological entities: an introduction to the ontology of physics for biology.

Science.gov (United States)

Cook, Daniel L; Bookstein, Fred L; Gennari, John H

2011-01-01

As biomedical investigators strive to integrate data and analyses across spatiotemporal scales and biomedical domains, they have recognized the benefits of formalizing languages and terminologies via computational ontologies. Although ontologies for biological entities-molecules, cells, organs-are well-established, there are no principled ontologies of physical properties-energies, volumes, flow rates-of those entities. In this paper, we introduce the Ontology of Physics for Biology (OPB), a reference ontology of classical physics designed for annotating biophysical content of growing repositories of biomedical datasets and analytical models. The OPB's semantic framework, traceable to James Clerk Maxwell, encompasses modern theories of system dynamics and thermodynamics, and is implemented as a computational ontology that references available upper ontologies. In this paper we focus on the OPB classes that are designed for annotating physical properties encoded in biomedical datasets and computational models, and we discuss how the OPB framework will facilitate biomedical knowledge integration. © 2011 Cook et al.

Intermediate physics for medicine and biology

CERN Document Server

Hobbie, Russell K

2015-01-01

This classic text has been used in over 20 countries by advanced undergraduate and beginning graduate students in biophysics, physiology, medical physics, neuroscience, and biomedical engineering. It bridges the gap between an introductory physics course and the application of physics to the life and biomedical sciences. Extensively revised and updated, the fifth edition incorporates new developments at the interface between physics and biomedicine. New coverage includes cyclotrons, photodynamic therapy, color vision, x-ray crystallography, the electron microscope, cochlear implants, deep brain stimulation, nanomedicine, and other topics highlighted in the National Research Council report BIO2010. As with the previous edition, the first half of the text is primarily biological physics, emphasizing the use of ideas from physics to understand biology and physiology, and the second half is primarily medical physics, describing the use of physics in medicine for diagnosis (mainly imaging) and therapy. Among the m...

WE-DE-202-00: Connecting Radiation Physics with Computational Biology

International Nuclear Information System (INIS)

2016-01-01

Radiation therapy for the treatment of cancer has been established as a highly precise and effective way to eradicate a localized region of diseased tissue. To achieve further significant gains in the therapeutic ratio, we need to move towards biologically optimized treatment planning. To achieve this goal, we need to understand how the radiation-type dependent patterns of induced energy depositions within the cell (physics) connect via molecular, cellular and tissue reactions to treatment outcome such as tumor control and undesirable effects on normal tissue. Several computational biology approaches have been developed connecting physics to biology. Monte Carlo simulations are the most accurate method to calculate physical dose distributions at the nanometer scale, however simulations at the DNA scale are slow and repair processes are generally not simulated. Alternative models that rely on the random formation of individual DNA lesions within one or two turns of the DNA have been shown to reproduce the clusters of DNA lesions, including single strand breaks (SSBs), double strand breaks (DSBs) without the need for detailed track structure simulations. Efficient computational simulations of initial DNA damage induction facilitate computational modeling of DNA repair and other molecular and cellular processes. Mechanistic, multiscale models provide a useful conceptual framework to test biological hypotheses and help connect fundamental information about track structure and dosimetry at the sub-cellular level to dose-response effects on larger scales. In this symposium we will learn about the current state of the art of computational approaches estimating radiation damage at the cellular and sub-cellular scale. How can understanding the physics interactions at the DNA level be used to predict biological outcome? We will discuss if and how such calculations are relevant to advance our understanding of radiation damage and its repair, or, if the underlying biological

WE-DE-202-00: Connecting Radiation Physics with Computational Biology

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

Radiation therapy for the treatment of cancer has been established as a highly precise and effective way to eradicate a localized region of diseased tissue. To achieve further significant gains in the therapeutic ratio, we need to move towards biologically optimized treatment planning. To achieve this goal, we need to understand how the radiation-type dependent patterns of induced energy depositions within the cell (physics) connect via molecular, cellular and tissue reactions to treatment outcome such as tumor control and undesirable effects on normal tissue. Several computational biology approaches have been developed connecting physics to biology. Monte Carlo simulations are the most accurate method to calculate physical dose distributions at the nanometer scale, however simulations at the DNA scale are slow and repair processes are generally not simulated. Alternative models that rely on the random formation of individual DNA lesions within one or two turns of the DNA have been shown to reproduce the clusters of DNA lesions, including single strand breaks (SSBs), double strand breaks (DSBs) without the need for detailed track structure simulations. Efficient computational simulations of initial DNA damage induction facilitate computational modeling of DNA repair and other molecular and cellular processes. Mechanistic, multiscale models provide a useful conceptual framework to test biological hypotheses and help connect fundamental information about track structure and dosimetry at the sub-cellular level to dose-response effects on larger scales. In this symposium we will learn about the current state of the art of computational approaches estimating radiation damage at the cellular and sub-cellular scale. How can understanding the physics interactions at the DNA level be used to predict biological outcome? We will discuss if and how such calculations are relevant to advance our understanding of radiation damage and its repair, or, if the underlying biological

Link between physics and biology

International Nuclear Information System (INIS)

Zaider, M.; Brenner, D.J.; Hall, E.J.; Kliauga, P.

1988-01-01

In the general causative chain: radiation physics-radiation chemistry - radiobiology - cancer treatment, physics, the initiating and therefore cardinal agent, continues to play the role of the poor relation. The main reason for this state of affairs rests with the fact that most models of radiation action - the actual link between physics and biology - make very little or no use of information concerning the radiation field: they are simply convenient vehicles for describing a large body of radiobiological data with analytical expressions containing a minimum number of parameters. In spite of their practical usefulness such models will not be further considered here. It is a reasonable assertion that the main goal of radiation biophysics is to elucidate the mechanisms of radiation action on biological entities

Biology-inspired AMO physics

International Nuclear Information System (INIS)

Mathur, Deepak

2015-01-01

This Topical Review presents an overview of increasingly robust interconnects that are being established between atomic, molecular and optical (AMO) physics and the life sciences. AMO physics, outgrowing its historical role as a facilitator—a provider of optical methodologies, for instance—now seeks to partner biology in its quest to link systems-level descriptions of biological entities to insights based on molecular processes. Of course, perspectives differ when AMO physicists and biologists consider various processes. For instance, while AMO physicists link molecular properties and dynamics to potential energy surfaces, these have to give way to energy landscapes in considerations of protein dynamics. But there are similarities also: tunnelling and non-adiabatic transitions occur both in protein dynamics and in molecular dynamics. We bring to the fore some such differences and similarities; we consider imaging techniques based on AMO concepts, like 4D fluorescence microscopy which allows access to the dynamics of cellular processes, multiphoton microscopy which offers a built-in confocality, and microscopy with femtosecond laser beams to saturate the suppression of fluorescence in spatially controlled fashion so as to circumvent the diffraction limit. Beyond imaging, AMO physics contributes with optical traps that probe the mechanical and dynamical properties of single ‘live’ cells, highlighting differences between healthy and diseased cells. Trap methodologies have also begun to probe the dynamics governing of neural stem cells adhering to each other to form neurospheres and, with squeezed light to probe sub-diffusive motion of yeast cells. Strong field science contributes not only by providing a source of energetic electrons and γ-rays via laser-plasma accelerations schemes, but also via filamentation and supercontinuum generation, enabling mainstream collision physics into play in diverse processes like DNA damage induced by low-energy collisions to

Physics and Biology Collaborate to Color the World

Science.gov (United States)

Liu, Dennis W. C.

2013-01-01

To understand how life works, it is essential to understand physics and chemistry. Most biologists have a clear notion of where chemistry fits into their life sciences research and teaching. Although we are physical beings, physics does not always find a place in the biology curriculum. Physics informs and enlightens biology in myriad dimensions,…

Toward University Modeling Instruction—Biology: Adapting Curricular Frameworks from Physics to Biology

Science.gov (United States)

Manthey, Seth; Brewe, Eric

2013-01-01

University Modeling Instruction (UMI) is an approach to curriculum and pedagogy that focuses instruction on engaging students in building, validating, and deploying scientific models. Modeling Instruction has been successfully implemented in both high school and university physics courses. Studies within the physics education research (PER) community have identified UMI's positive impacts on learning gains, equity, attitudinal shifts, and self-efficacy. While the success of this pedagogical approach has been recognized within the physics community, the use of models and modeling practices is still being developed for biology. Drawing from the existing research on UMI in physics, we describe the theoretical foundations of UMI and how UMI can be adapted to include an emphasis on models and modeling for undergraduate introductory biology courses. In particular, we discuss our ongoing work to develop a framework for the first semester of a two-semester introductory biology course sequence by identifying the essential basic models for an introductory biology course sequence. PMID:23737628

Toward university modeling instruction--biology: adapting curricular frameworks from physics to biology.

Science.gov (United States)

Manthey, Seth; Brewe, Eric

2013-06-01

University Modeling Instruction (UMI) is an approach to curriculum and pedagogy that focuses instruction on engaging students in building, validating, and deploying scientific models. Modeling Instruction has been successfully implemented in both high school and university physics courses. Studies within the physics education research (PER) community have identified UMI's positive impacts on learning gains, equity, attitudinal shifts, and self-efficacy. While the success of this pedagogical approach has been recognized within the physics community, the use of models and modeling practices is still being developed for biology. Drawing from the existing research on UMI in physics, we describe the theoretical foundations of UMI and how UMI can be adapted to include an emphasis on models and modeling for undergraduate introductory biology courses. In particular, we discuss our ongoing work to develop a framework for the first semester of a two-semester introductory biology course sequence by identifying the essential basic models for an introductory biology course sequence.

Catalogue of methods of calculation, interpolation, smoothing, and reduction for the physical, chemical, and biological parameters of deep hydrology (CATMETH) (NODC Accession 7700442)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The document presents the methods, formulas and citations used by the BNDO to process physical, chemical, and biological data for deep hydrology including...

Intermediate Physics for Medicine and Biology

CERN Document Server

Hobbie, Russell K

2007-01-01

Intended for advanced undergraduate and beginning graduate students in biophysics, physiology, medical physics, cell biology, and biomedical engineering, this wide-ranging text bridges the gap between introductory physics and its application to the life and biomedical sciences. This extensively revised and updated fourth edition reflects new developments at the burgeoning interface between physics and biomedicine. Among the many topics treated are: forces in the skeletal system; fluid flow, with examples from the circulatory system; the logistic equation; scaling; transport of neutral particles by diffusion and by solvent drag; membranes and osmosis; equipartition of energy in statistical mechanics; the chemical potential and free energy; biological magnetic fields; membranes and gated channels in membranes; linear and nonlinear feedback systems; nonlinear phenomena, including biological clocks and chaotic behavior; signal analysis, noise and stochastic resonance detection of weak signals; image formation and...

Physical parameters and biological effects of the LVR-15 epithermal neutron beam

International Nuclear Information System (INIS)

Burian, J.; Marek, M.; Rejchrt, J.; Viererbl, L.; Gambarini, G.; Mares, V.; Vanossi, E.; Judas, L.

2006-01-01

Monitoring of the physical and biological properties of the epithermal neutron beam constructed at the multipurpose LVR-15 nuclear reactor for NCT therapy of brain tumors showed that its physical and biological properties are stable in time and independent on an ad hoc reconfiguration of the reactor core before its therapeutic use. Physical parameters were monitored by measurement of the neutron spectrum, neutron profile, fast neutron kerma rate in tissue and photon absorbed dose, the gel dosimetry was used with the group of standard measurement methods. The RBE of the beam, as evaluated by 3 different biological models, including mouse intestine crypt regeneration assay, germinative zones of the immature rat brain and C6 glioma cells in culture, ranged from 1.70 to 1.99. (author)

New Hybrid Monte Carlo methods for efficient sampling. From physics to biology and statistics

International Nuclear Information System (INIS)

Akhmatskaya, Elena; Reich, Sebastian

2011-01-01

We introduce a class of novel hybrid methods for detailed simulations of large complex systems in physics, biology, materials science and statistics. These generalized shadow Hybrid Monte Carlo (GSHMC) methods combine the advantages of stochastic and deterministic simulation techniques. They utilize a partial momentum update to retain some of the dynamical information, employ modified Hamiltonians to overcome exponential performance degradation with the system’s size and make use of multi-scale nature of complex systems. Variants of GSHMCs were developed for atomistic simulation, particle simulation and statistics: GSHMC (thermodynamically consistent implementation of constant-temperature molecular dynamics), MTS-GSHMC (multiple-time-stepping GSHMC), meso-GSHMC (Metropolis corrected dissipative particle dynamics (DPD) method), and a generalized shadow Hamiltonian Monte Carlo, GSHmMC (a GSHMC for statistical simulations). All of these are compatible with other enhanced sampling techniques and suitable for massively parallel computing allowing for a range of multi-level parallel strategies. A brief description of the GSHMC approach, examples of its application on high performance computers and comparison with other existing techniques are given. Our approach is shown to resolve such problems as resonance instabilities of the MTS methods and non-preservation of thermodynamic equilibrium properties in DPD, and to outperform known methods in sampling efficiency by an order of magnitude. (author)

Physical models of biological information and adaptation.

Science.gov (United States)

Stuart, C I

1985-04-07

The bio-informational equivalence asserts that biological processes reduce to processes of information transfer. In this paper, that equivalence is treated as a metaphor with deeply anthropomorphic content of a sort that resists constitutive-analytical definition, including formulation within mathematical theories of information. It is argued that continuance of the metaphor, as a quasi-theoretical perspective in biology, must entail a methodological dislocation between biological and physical science. It is proposed that a general class of functions, drawn from classical physics, can serve to eliminate the anthropomorphism. Further considerations indicate that the concept of biological adaptation is central to the general applicability of the informational idea in biology; a non-anthropomorphic treatment of adaptive phenomena is suggested in terms of variational principles.

Physics and biology of protein

International Nuclear Information System (INIS)

Go, Nobuhiro

2008-01-01

This is a record of my lecture given at the occasion of Yukawa-Tomonaga Centennial Symposium. At first I will mention very briefly how Yukawa contributed to the development of biophysics in Japan. Then I will be concerned with the relationship between physics and biology by discussing various aspects of protein. How far and in what sense can physics approach the essence of protein? In what aspects are something beyond physics important? (author)

Single-molecule experiments in biological physics: methods and applications.

Science.gov (United States)

Ritort, F

2006-08-16

I review single-molecule experiments (SMEs) in biological physics. Recent technological developments have provided the tools to design and build scientific instruments of high enough sensitivity and precision to manipulate and visualize individual molecules and measure microscopic forces. Using SMEs it is possible to manipulate molecules one at a time and measure distributions describing molecular properties, characterize the kinetics of biomolecular reactions and detect molecular intermediates. SMEs provide additional information about thermodynamics and kinetics of biomolecular processes. This complements information obtained in traditional bulk assays. In SMEs it is also possible to measure small energies and detect large Brownian deviations in biomolecular reactions, thereby offering new methods and systems to scrutinize the basic foundations of statistical mechanics. This review is written at a very introductory level, emphasizing the importance of SMEs to scientists interested in knowing the common playground of ideas and the interdisciplinary topics accessible by these techniques. The review discusses SMEs from an experimental perspective, first exposing the most common experimental methodologies and later presenting various molecular systems where such techniques have been applied. I briefly discuss experimental techniques such as atomic-force microscopy (AFM), laser optical tweezers (LOTs), magnetic tweezers (MTs), biomembrane force probes (BFPs) and single-molecule fluorescence (SMF). I then present several applications of SME to the study of nucleic acids (DNA, RNA and DNA condensation) and proteins (protein-protein interactions, protein folding and molecular motors). Finally, I discuss applications of SMEs to the study of the nonequilibrium thermodynamics of small systems and the experimental verification of fluctuation theorems. I conclude with a discussion of open questions and future perspectives.

Single-molecule experiments in biological physics: methods and applications

International Nuclear Information System (INIS)

Ritort, F

2006-01-01

I review single-molecule experiments (SMEs) in biological physics. Recent technological developments have provided the tools to design and build scientific instruments of high enough sensitivity and precision to manipulate and visualize individual molecules and measure microscopic forces. Using SMEs it is possible to manipulate molecules one at a time and measure distributions describing molecular properties, characterize the kinetics of biomolecular reactions and detect molecular intermediates. SMEs provide additional information about thermodynamics and kinetics of biomolecular processes. This complements information obtained in traditional bulk assays. In SMEs it is also possible to measure small energies and detect large Brownian deviations in biomolecular reactions, thereby offering new methods and systems to scrutinize the basic foundations of statistical mechanics. This review is written at a very introductory level, emphasizing the importance of SMEs to scientists interested in knowing the common playground of ideas and the interdisciplinary topics accessible by these techniques. The review discusses SMEs from an experimental perspective, first exposing the most common experimental methodologies and later presenting various molecular systems where such techniques have been applied. I briefly discuss experimental techniques such as atomic-force microscopy (AFM), laser optical tweezers (LOTs), magnetic tweezers (MTs), biomembrane force probes (BFPs) and single-molecule fluorescence (SMF). I then present several applications of SME to the study of nucleic acids (DNA, RNA and DNA condensation) and proteins (protein-protein interactions, protein folding and molecular motors). Finally, I discuss applications of SMEs to the study of the nonequilibrium thermodynamics of small systems and the experimental verification of fluctuation theorems. I conclude with a discussion of open questions and future perspectives. (topical review)

When physics is not "just physics": complexity science invites new measurement frames for exploring the physics of cognitive and biological development.

Science.gov (United States)

Kelty-Stephen, Damian; Dixon, James A

2012-01-01

The neurobiological sciences have struggled to resolve the physical foundations for biological and cognitive phenomena with a suspicion that biological and cognitive systems, capable of exhibiting and contributing to structure within themselves and through their contexts, are fundamentally distinct or autonomous from purely physical systems. Complexity science offers new physics-based approaches to explaining biological and cognitive phenomena. In response to controversy over whether complexity science might seek to "explain away" biology and cognition as "just physics," we propose that complexity science serves as an application of recent advances in physics to phenomena in biology and cognition without reducing or undermining the integrity of the phenomena to be explained. We highlight that physics is, like the neurobiological sciences, an evolving field and that the threat of reduction is overstated. We propose that distinctions between biological and cognitive systems from physical systems are pretheoretical and thus optional. We review our own work applying insights from post-classical physics regarding turbulence and fractal fluctuations to the problems of developing cognitive structure. Far from hoping to reduce biology and cognition to "nothing but" physics, we present our view that complexity science offers new explanatory frameworks for considering physical foundations of biological and cognitive phenomena.

Microbiology and atmospheric processes: biological, physical and chemical characterization of aerosol particles

Directory of Open Access Journals (Sweden)

D. G. Georgakopoulos

2009-04-01

Full Text Available The interest in bioaerosols has traditionally been linked to health hazards for humans, animals and plants. However, several components of bioaerosols exhibit physical properties of great significance for cloud processes, such as ice nucleation and cloud condensation. To gain a better understanding of their influence on climate, it is therefore important to determine the composition, concentration, seasonal fluctuation, regional diversity and evolution of bioaerosols. In this paper, we will review briefly the existing techniques for detection, quantification, physical and chemical analysis of biological particles, attempting to bridge physical, chemical and biological methods for analysis of biological particles and integrate them with aerosol sampling techniques. We will also explore some emerging spectroscopy techniques for bulk and single-particle analysis that have potential for in-situ physical and chemical analysis. Lastly, we will outline open questions and further desired capabilities (e.g., in-situ, sensitive, both broad and selective, on-line, time-resolved, rapid, versatile, cost-effective techniques required prior to comprehensive understanding of chemical and physical characterization of bioaerosols.

Comparison in the determination of absorbed dose by biological and physical methods to patients in treatment of cardiac intervention

International Nuclear Information System (INIS)

Guerrero C, C.; Arceo M, C.

2014-10-01

The use of less invasive procedures, lower risk and quick recovery as cardiac intervention have proven to be an efficient alternative to reestablish the correct bloodstream of the patient. In this case the patient is subjected to values of absorbed dose above to which is subjected in a study with X-rays for medical diagnosis, and this can cause radiation injuries to the skin. The target organ, in this case can be exposed to doses of 2 Gy above. Different methods to estimate the dose were use, physical by Radiochromic film, as biological by dicentric analysis. Both methods provided additional information demonstrating thus the risk in the target organ and the patient. The most reliable biological indicator of exposure to ionizing radiation is the study of chromosomal aberrations, specifically dicentric in human lymphocytes. This test allowed establishing the exposure dose depending of the damage. (Author)

Optimizing Introductory Physics for the Life Sciences: Placing Physics in Biological Context

Science.gov (United States)

Crouch, Catherine

2014-03-01

Physics is a critical foundation for today's life sciences and medicine. However, the physics content and ways of thinking identified by life scientists as most important for their fields are often not taught, or underemphasized, in traditional introductory physics courses. Furthermore, such courses rarely give students practice using physics to understand living systems in a substantial way. Consequently, students are unlikely to recognize the value of physics to their chosen fields, or to develop facility in applying physics to biological systems. At Swarthmore, as at several other institutions engaged in reforming this course, we have reorganized the introductory course for life science students around touchstone biological examples, in which fundamental physics contributes significantly to understanding biological phenomena or research techniques, in order to make explicit the value of physics to the life sciences. We have also focused on the physics topics and approaches most relevant to biology while seeking to develop rigorous qualitative reasoning and quantitative problem solving skills, using established pedagogical best practices. Each unit is motivated by and culminates with students analyzing one or more touchstone examples. For example, in the second semester we emphasize electric potential and potential difference more than electric field, and start from students' typically superficial understanding of the cell membrane potential and of electrical interactions in biochemistry to help them develop a more sophisticated understanding of electric forces, field, and potential, including in the salt water environment of life. Other second semester touchstones include optics of vision and microscopes, circuit models for neural signaling, and magnetotactic bacteria. When possible, we have adapted existing research-based curricular materials to support these examples. This talk will describe the design and development process for this course, give examples of

Biology meets Physics: Reductionism and Multi-scale Modeling of Morphogenesis

DEFF Research Database (Denmark)

Green, Sara; Batterman, Robert

2017-01-01

A common reductionist assumption is that macro-scale behaviors can be described "bottom-up" if only sufficient details about lower-scale processes are available. The view that an "ideal" or "fundamental" physics would be sufficient to explain all macro-scale phenomena has been met with criticism ...... modeling in developmental biology. In such contexts, the relation between models at different scales and from different disciplines is neither reductive nor completely autonomous, but interdependent....... from philosophers of biology. Specifically, scholars have pointed to the impossibility of deducing biological explanations from physical ones, and to the irreducible nature of distinctively biological processes such as gene regulation and evolution. This paper takes a step back in asking whether bottom......-up modeling is feasible even when modeling simple physical systems across scales. By comparing examples of multi-scale modeling in physics and biology, we argue that the “tyranny of scales” problem present a challenge to reductive explanations in both physics and biology. The problem refers to the scale...

Radiation effects analysis in a group of interventional radiologists using biological and physical dosimetry methods

Energy Technology Data Exchange (ETDEWEB)

Ramos, M., E-mail: WEMLmirapas@iqn.upv.e [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Montoro, A.; Almonacid, M. [Radiation Protection Service, Hospital Universitario La Fe Valencia (Spain); Ferrer, S. [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Barquinero, J.F. [Biological Dosimetry Service, Unit of Anthropology, Department of Animal and Vegetable Biology and Ecology, Universitat Autonoma de Barcelona (UAB) (Spain); Tortosa, R. [Radiation Protection Service, Hospital Universitario La Fe Valencia (Spain); Verdu, G. [Department of Chemical and Nuclear Engineering, Polytechnic University of Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Rodriguez, P. [Biological Dosimetry Service, Unit of Anthropology, Department of Animal and Vegetable Biology and Ecology, Universitat Autonoma de Barcelona (UAB) (Spain); Barrios, L.L. [Department of Physiology and Cellular Biology, Unit of Cellular Biology (UAB) (Spain); Villaescusa, J.I. [Radiation Protection Service, Hospital Universitario La Fe Valencia (Spain)

2010-08-15

Interventional radiologists and staff members are frequently exposed to protracted and fractionated low doses of ionizing radiation, which extend during all their professional activities. These exposures can derive, due to the effects of direct and scattered radiation, in deterministic effects (radiodermitis, aged skin, cataracts, telangiectasia in nasal region, vasocellular epitelioms, hands depilation) and/or stochastic ones (cancer incidence). A methodology has been proposed for estimating the radiation risk or detriment from a group of six exposed interventional radiologists of the Hospital Universitario La Fe (Valencia, Spain), which had developed general exposition symptoms attributable to deterministic effects of ionizing radiation. Equivalent doses have been periodically registered using TLD's and wrist dosimeters, H{sub p}(10) and H{sub p}(0.07), respectively, and estimated through the observation of translocations in lymphocytes of peripheral blood (biological methods), by extrapolating the yield of translocations to their respective dose-effect curves. The software RADRISK has been applied for estimating radiation risks in these occupational radiation exposures. This software is based on transport models from epidemiological studies of population exposed to external sources of ionizing radiation, such as Hiroshima and Nagasaki atomic bomb survivors [UNSCEAR, Sources and effects of ionizing radiation: 2006 report to the general assembly, with scientific annexes. New York: United Nations; 2006]. The minimum and maximum average excess ratio for skin cancer has been, using wrist physical doses, of [1.03x10{sup -3}, 5.06x10{sup -2}], concluding that there is not an increased risk of skin cancer incidence. The minimum and maximum average excess ratio for leukemia has been, using TLD physical doses, of [7.84x10{sup -2}, 3.36x10{sup -1}], and using biological doses, of [1.40x10{sup -1}, 1.51], which is considerably higher than incidence rates, showing an

Graphical methods and Cold War scientific practice: the Stommel Diagram's intriguing journey from the physical to the biological environmental sciences.

Science.gov (United States)

Vance, Tiffany C; Doel, Ronald E

2010-01-01

In the last quarter of the twentieth century, an innovative three-dimensional graphical technique was introduced into biological oceanography and ecology, where it spread rapidly. Used to improve scientists' understanding of the importance of scale within oceanic ecosystems, this influential diagram addressed biological scales from phytoplankton to fish, physical scales from diurnal tides to ocean currents, and temporal scales from hours to ice ages. Yet the Stommel Diagram (named for physical oceanographer Henry Stommel, who created it in 1963) had not been devised to aid ecological investigations. Rather, Stommel intended it to help plan large-scale research programs in physical oceanography, particularly as Cold War research funding enabled a dramatic expansion of physical oceanography in the 1960s. Marine ecologists utilized the Stommel Diagram to enhance research on biological production in ocean environments, a key concern by the 1970s amid growing alarm about overfishing and ocean pollution. Before the end of the twentieth century, the diagram had become a significant tool within the discipline of ecology. Tracing the path that Stommel's graphical techniques traveled from the physical to the biological environmental sciences reveals a great deal about practices in these distinct research communities and their relative professional and institutional standings in the Cold War era. Crucial to appreciating the course of that path is an understanding of the divergent intellectual and social contexts of the physical versus the biological environmental sciences.

Pragmatic information in biology and physics.

Science.gov (United States)

Roederer, Juan G

2016-03-13

I will show how an objective definition of the concept of information and the consideration of recent results about information processing in the human brain help clarify some fundamental aspects of physics and biology. Rather than attempting to define information ab initio, I introduce the concept of interaction between material bodies as a primary concept. Two distinct categories can be identified: (i) interactions which can always be reduced to a superposition of physical interactions (forces) between elementary constituents; and (ii) interactions between complex bodies which cannot be expressed as a superposition of interactions between parts, and in which patterns and forms (in space and/or time) play the determining role. Pragmatic information is then defined as the link between a given pattern and the ensuing pattern-specific change. I will show that pragmatic information is a biological concept; it plays no active role in the purely physical domain-it only does so when a living organism intervenes. The consequences for physics (including foundations of quantum mechanics) and biology (including brain function) will be discussed. This will include speculations about three fundamental transitions, from the quantum to the classical domain, from natural inanimate to living systems, and from subhuman to human brain information-processing operations, introduced here in their direct connection with the concept of pragmatic information. © 2016 The Author(s).

Complex network problems in physics, computer science and biology

Science.gov (United States)

Cojocaru, Radu Ionut

There is a close relation between physics and mathematics and the exchange of ideas between these two sciences are well established. However until few years ago there was no such a close relation between physics and computer science. Even more, only recently biologists started to use methods and tools from statistical physics in order to study the behavior of complex system. In this thesis we concentrate on applying and analyzing several methods borrowed from computer science to biology and also we use methods from statistical physics in solving hard problems from computer science. In recent years physicists have been interested in studying the behavior of complex networks. Physics is an experimental science in which theoretical predictions are compared to experiments. In this definition, the term prediction plays a very important role: although the system is complex, it is still possible to get predictions for its behavior, but these predictions are of a probabilistic nature. Spin glasses, lattice gases or the Potts model are a few examples of complex systems in physics. Spin glasses and many frustrated antiferromagnets map exactly to computer science problems in the NP-hard class defined in Chapter 1. In Chapter 1 we discuss a common result from artificial intelligence (AI) which shows that there are some problems which are NP-complete, with the implication that these problems are difficult to solve. We introduce a few well known hard problems from computer science (Satisfiability, Coloring, Vertex Cover together with Maximum Independent Set and Number Partitioning) and then discuss their mapping to problems from physics. In Chapter 2 we provide a short review of combinatorial optimization algorithms and their applications to ground state problems in disordered systems. We discuss the cavity method initially developed for studying the Sherrington-Kirkpatrick model of spin glasses. We extend this model to the study of a specific case of spin glass on the Bethe

Implementation of statistical analysis methods for medical physics data

International Nuclear Information System (INIS)

Teixeira, Marilia S.; Pinto, Nivia G.P.; Barroso, Regina C.; Oliveira, Luis F.

2009-01-01

The objective of biomedical research with different radiation natures is to contribute for the understanding of the basic physics and biochemistry of the biological systems, the disease diagnostic and the development of the therapeutic techniques. The main benefits are: the cure of tumors through the therapy, the anticipated detection of diseases through the diagnostic, the using as prophylactic mean for blood transfusion, etc. Therefore, for the better understanding of the biological interactions occurring after exposure to radiation, it is necessary for the optimization of therapeutic procedures and strategies for reduction of radioinduced effects. The group pf applied physics of the Physics Institute of UERJ have been working in the characterization of biological samples (human tissues, teeth, saliva, soil, plants, sediments, air, water, organic matrixes, ceramics, fossil material, among others) using X-rays diffraction and X-ray fluorescence. The application of these techniques for measurement, analysis and interpretation of the biological tissues characteristics are experimenting considerable interest in the Medical and Environmental Physics. All quantitative data analysis must be initiated with descriptive statistic calculation (means and standard deviations) in order to obtain a previous notion on what the analysis will reveal. It is well known que o high values of standard deviation found in experimental measurements of biologicals samples can be attributed to biological factors, due to the specific characteristics of each individual (age, gender, environment, alimentary habits, etc). This work has the main objective the development of a program for the use of specific statistic methods for the optimization of experimental data an analysis. The specialized programs for this analysis are proprietary, another objective of this work is the implementation of a code which is free and can be shared by the other research groups. As the program developed since the

PREFACE: Nanobiology: from physics and engineering to biology

Science.gov (United States)

Nussinov, Ruth; Alemán, Carlos

2006-03-01

Biological systems are inherently nano in scale. Unlike nanotechnology, nanobiology is characterized by the interplay between physics, materials science, synthetic organic chemistry, engineering and biology. Nanobiology is a new discipline, with the potential of revolutionizing medicine: it combines the tools, ideas and materials of nanoscience and biology; it addresses biological problems that can be studied and solved by nanotechnology; it devises ways to construct molecular devices using biomacromolecules; and it attempts to build molecular machines utilizing concepts seen in nature. Its ultimate aim is to be able to predictably manipulate these, tailoring them to specified needs. Nanobiology targets biological systems and uses biomacromolecules. Hence, on the one hand, nanobiology is seemingly constrained in its scope as compared to general nanotechnology. Yet the amazing intricacy of biological systems, their complexity, and the richness of the shapes and properties provided by the biological polymers, enrich nanobiology. Targeting biological systems entails comprehension of how they work and the ability to use their components in design. From the physical standpoint, ultimately, if we are to understand biology we need to learn how to apply physical principles to figure out how these systems actually work. The goal of nanobiology is to assist in probing these systems at the appropriate length scale, heralding a new era in the biological, physical and chemical sciences. Biology is increasingly asking quantitative questions. Quantitation is essential if we are to understand how the cell works, and the details of its regulation. The physical sciences provide tools and strategies to obtain accurate measurements and simulate the information to allow comprehension of the processes. Nanobiology is at the interface of the physical and the biological sciences. Biology offers to the physical sciences fascinating problems, sophisticated systems and a rich repertoire of

The Physics of Marine Biology.

Science.gov (United States)

Conn, Kathleen

1992-01-01

Discusses ways in which marine biology can be integrated into the physics classroom. Topics suggested for incorporation include the harmonic motion of ocean waves, ocean currents, the interaction of visible light with ocean water, pressure, light absorption, and sound transfer in water. (MDH)

Introductory physics in biological context: An approach to improve introductory physics for life science students

Science.gov (United States)

Crouch, Catherine H.; Heller, Kenneth

2014-05-01

We describe restructuring the introductory physics for life science students (IPLS) course to better support these students in using physics to understand their chosen fields. Our courses teach physics using biologically rich contexts. Specifically, we use examples in which fundamental physics contributes significantly to understanding a biological system to make explicit the value of physics to the life sciences. This requires selecting the course content to reflect the topics most relevant to biology while maintaining the fundamental disciplinary structure of physics. In addition to stressing the importance of the fundamental principles of physics, an important goal is developing students' quantitative and problem solving skills. Our guiding pedagogical framework is the cognitive apprenticeship model, in which learning occurs most effectively when students can articulate why what they are learning matters to them. In this article, we describe our courses, summarize initial assessment data, and identify needs for future research.

Surface treatments for biological, chemical and physical applications

CERN Document Server

Karaman, Mustafa

2017-01-01

A step-by-step guide to the topic with a mix of theory and practice in the fields of biology, chemistry and physics. Straightforward and well-structured, the first chapter introduces fundamental aspects of surface treatments, after which examples from nature are given. Subsequent chapters discuss various methods to surface modification, including chemical and physical approaches, followed by the characterization of the functionalized surfaces. Applications discussed include the lotus effect, diffusion barriers, enzyme immobilization and catalysis. Finally, the book concludes with a look at future technology advances. Throughout the text, tutorials and case studies are used for training purposes to grant a deeper understanding of the topic, resulting in an essential reference for students as well as for experienced engineers in R&D.

Preservice Teachers' Epistemological Beliefs in Physics, Chemistry, and Biology: A Mixed Study

Science.gov (United States)

Topcu, Mustafa Sami

2013-01-01

The purposes of the study were to assess preservice teachers' domain-specific epistemological beliefs and to investigate whether preservice teachers distinguish disciplinary differences (physics, chemistry, and biology) in domain-specific epistemological beliefs. Mixed-method research design guided the present research. The researcher explored…

Photon activation method to the investigation of bioobjects content for juridical-biological examination

International Nuclear Information System (INIS)

Dikiy, N.P.; Dyachenko, A.F.; Lyashko, Yu.V.; Medvedeva, E.P.; Uvarov, V.L.; Borovlev, V.I.

2009-01-01

Possibilities of the use of nuclear-physical methods for definition of element composition of biological objects (hair of animals) with the target of receipt of additional evidentiary information at the decision of diagnostics and identification problems within the limits of forensic-biological examination are shown

Physical mechanisms of biological molecular motors

International Nuclear Information System (INIS)

Miller, John H. Jr.; Vajrala, Vijayanand; Infante, Hans L.; Claycomb, James R.; Palanisami, Akilan; Fang Jie; Mercier, George T.

2009-01-01

Biological motors generally fall into two categories: (1) those that convert chemical into mechanical energy via hydrolysis of a nucleoside triphosphate, usually adenosine triphosphate, regarded as life's chemical currency of energy and (2) membrane bound motors driven directly by an ion gradient and/or membrane potential. Here we argue that electrostatic interactions play a vital role for both types of motors and, therefore, the tools of physics can greatly contribute to understanding biological motors

Physical mechanisms of biological molecular motors

Energy Technology Data Exchange (ETDEWEB)

Miller, John H. Jr. [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Ste. 617 SR1 Houston, TX 77204-5005 (United States)], E-mail: jhmiller@uh.edu; Vajrala, Vijayanand; Infante, Hans L. [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Ste. 617 SR1 Houston, TX 77204-5005 (United States); Claycomb, James R. [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Ste. 617 SR1 Houston, TX 77204-5005 (United States); Department of Mathematics and Physics, Houston Baptist University, 7502 Fondren Road, Houston, TX 77074-3298 (United States); Palanisami, Akilan; Fang Jie; Mercier, George T. [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Ste. 617 SR1 Houston, TX 77204-5005 (United States)

2009-03-01

Biological motors generally fall into two categories: (1) those that convert chemical into mechanical energy via hydrolysis of a nucleoside triphosphate, usually adenosine triphosphate, regarded as life's chemical currency of energy and (2) membrane bound motors driven directly by an ion gradient and/or membrane potential. Here we argue that electrostatic interactions play a vital role for both types of motors and, therefore, the tools of physics can greatly contribute to understanding biological motors.

Physical activity and biological maturation: a systematic review

Directory of Open Access Journals (Sweden)

Eliane Denise Araújo Bacil

2015-03-01

Full Text Available OBJECTIVE: To analyze the association between physical activity (PA and biological maturation in children and adolescents. DATA SOURCE: We performed a systematic review in April 2013 in the electronic databases of PubMed/MEDLINE, SportDiscus, Web of Science and LILACS without time restrictions. A total of 628 potentially relevant articles were identified and 10 met the inclusion criteria for this review: cross-sectional or longitudinal studies, published in Portuguese, English or Spanish, with schoolchildren aged 9-15 years old of both genders. DATA SYNTHESIS: Despite the heterogeneity of the studies, there was an inverse association between PA and biological maturation. PA decreases with increased biological and chronological age in both genders. Boys tend to be more physically active than girls; however, when controlling for biological age, the gender differences disappear. The association between PA and timing of maturation varies between the genders. Variation in the timing of biological maturation affects the tracking of PA in early adolescent girls. This review suggests that mediators (BMI, depression, low self-esteem, and concerns about body weight can explain the association between PA and biological maturation. CONCLUSIONS: There is an association between PA and biological maturation. PA decreases with increasing biological age with no differences between genders. As for the timing of biological maturation, this association varies between genders.

Physics with illustrative examples from medicine and biology

CERN Document Server

Benedek, George B

Physics: with illustrative examples from medicine and biology is a three-volume set of textbooks in introductory physics written at the calculus level and designed primarily for students with career objectives in the life sciences.

Stochastic Methods in Biology

CERN Document Server

Kallianpur, Gopinath; Hida, Takeyuki

1987-01-01

The use of probabilistic methods in the biological sciences has been so well established by now that mathematical biology is regarded by many as a distinct dis­ cipline with its own repertoire of techniques. The purpose of the Workshop on sto­ chastic methods in biology held at Nagoya University during the week of July 8-12, 1985, was to enable biologists and probabilists from Japan and the U. S. to discuss the latest developments in their respective fields and to exchange ideas on the ap­ plicability of the more recent developments in stochastic process theory to problems in biology. Eighteen papers were presented at the Workshop and have been grouped under the following headings: I. Population genetics (five papers) II. Measure valued diffusion processes related to population genetics (three papers) III. Neurophysiology (two papers) IV. Fluctuation in living cells (two papers) V. Mathematical methods related to other problems in biology, epidemiology, population dynamics, etc. (six papers) An important f...

Physical biology of human brain development

Directory of Open Access Journals (Sweden)

Silvia eBudday

2015-07-01

Full Text Available Neurodevelopment is a complex, dynamic process that involves a precisely orchestrated sequence of genetic, environmental, biochemical, and physical events. Developmental biology and genetics have shaped our understanding of the molecular and cellular mechanisms during neurodevelopment. Recent studies suggest that physical forces play a central role in translating these cellular mechanisms into the complex surface morphology of the human brain. However, the precise impact of neuronal differentiation, migration, and connection on the physical forces during cortical folding remains unknown. Here we review the cellular mechanisms of neurodevelopment with a view towards surface morphogenesis, pattern selection, and evolution of shape. We revisit cortical folding as the instability problem of constrained differential growth in a multi-layered system. To identify the contributing factors of differential growth, we map out the timeline of neurodevelopment in humans and highlight the cellular events associated with extreme radial and tangential expansion. We demonstrate how computational modeling of differential growth can bridge the scales-from phenomena on the cellular level towards form and function on the organ level-to make quantitative, personalized predictions. Physics-based models can quantify cortical stresses, identify critical folding conditions, rationalize pattern selection, and predict gyral wavelengths and gyrification indices. We illustrate that physical forces can explain cortical malformations as emergent properties of developmental disorders. Combining biology and physics holds promise to advance our understanding of human brain development and enable early diagnostics of cortical malformations with the ultimate goal to improve treatment of neurodevelopmental disorders including epilepsy, autism spectrum disorders, and schizophrenia.

Biological, chemical and medical physics

International Nuclear Information System (INIS)

1990-01-01

This is an overview of the actual situation in Brazil, concerning three important areas of physics: biological, chemical and medical. It gives a brief historical of research in these areas. It talks as well, about perspectives and financing. It contains many tables with the main research groups in activity in Brazilian institutions. (A.C.A.S.)

Research on condensed matter and atomic physics using major experimental facilities and devices: Physics, chemistry, biology. Reports on results. Vol. 2. 3. Solid state physics and materials science

International Nuclear Information System (INIS)

1993-01-01

This report in three volumes substantiates the contents of the programme survey published in September 1989. The progress reports cover the following research areas: Vol. I, (1). Atomic and molecular physics - free atoms, molecules, macromolecules, clusters, matrix-isolated atoms and molecules. (2) Physics and chemistry of surfaces and interfaces - epitaxy, surface structure, adsorption, electrical, magnetic, and optical properties, thin films, synthetic layer structure. Vol. II, (3). Solid-state physics, and materials science -structural research, lattice dynamics, magnetic structure and dynamics, electronic states; load; spin and pulse density fluctuations; diffusion and internal motion, defects, unordered systems and liquids. Vol. III, (4). Chemistry - bonding and structure, kinetics and reaction mechanisms, polymer research, analysis and synthesis. (5). Biology, - structure and dynamics of biological macromolecules, membrane and cell biology. (6) Development of methods and instruments - neutron sources, synchrotron sources, special accelerators, research with interlinked systems and devices. (orig.) [de

Physics in Brazil in the next decade: atomic, molecular and optical physics, biological, chemical and medical physics, physics teaching and plasma physics

International Nuclear Information System (INIS)

1990-01-01

This is an overview of physics in Brazil in the next decade. It is specially concerned with atomic, molecular and optical physics, biological chemical and medical physics, and also teaching of physics and plasma physics. It presents the main research groups in Brazil in the above mentioned areas. It talks as well, about financing new projects and the costs involved to improve these areas. (A.C.A.S.)

TOPICAL REVIEW: Single-molecule experiments in biological physics: methods and applications

Science.gov (United States)

Ritort, F.

2006-08-01

I review single-molecule experiments (SMEs) in biological physics. Recent technological developments have provided the tools to design and build scientific instruments of high enough sensitivity and precision to manipulate and visualize individual molecules and measure microscopic forces. Using SMEs it is possible to manipulate molecules one at a time and measure distributions describing molecular properties, characterize the kinetics of biomolecular reactions and detect molecular intermediates. SMEs provide additional information about thermodynamics and kinetics of biomolecular processes. This complements information obtained in traditional bulk assays. In SMEs it is also possible to measure small energies and detect large Brownian deviations in biomolecular reactions, thereby offering new methods and systems to scrutinize the basic foundations of statistical mechanics. This review is written at a very introductory level, emphasizing the importance of SMEs to scientists interested in knowing the common playground of ideas and the interdisciplinary topics accessible by these techniques. The review discusses SMEs from an experimental perspective, first exposing the most common experimental methodologies and later presenting various molecular systems where such techniques have been applied. I briefly discuss experimental techniques such as atomic-force microscopy (AFM), laser optical tweezers (LOTs), magnetic tweezers (MTs), biomembrane force probes (BFPs) and single-molecule fluorescence (SMF). I then present several applications of SME to the study of nucleic acids (DNA, RNA and DNA condensation) and proteins (protein-protein interactions, protein folding and molecular motors). Finally, I discuss applications of SMEs to the study of the nonequilibrium thermodynamics of small systems and the experimental verification of fluctuation theorems. I conclude with a discussion of open questions and future perspectives.

Research on condensed matter and atomic physics, using major experimental facilities and devices: Physics, chemistry, biology. Reports on results. Vol. 1. 1. Atomic and molecular physics. 2. Physics and chemistry of surfaces and interfaces

International Nuclear Information System (INIS)

1993-01-01

This report in three volumes substantiates the contents of the programme survey published in September 1989. The progress reports cover the following research areas: Vol. I, (1). Atomic and molecular physics - free atoms, molecules, macromolecules, clusters, matrix-isolated atoms and molecules. (2) Physics and chemistry of surfaces and interfaces - epitaxy, surface structure, adsorption, electrical, magnetic, and optical properties, thin films, synthetic layer structure. Vol. II, (3). Solid-state physics, and materials science -structural research, lattice dynamics, magnetic structure and dynamics, electronic states; load; spin and pulse density fluctuations; diffusion and internal motion, defects, unordered systems and liquids. Vol. III, (4). Chemistry - bonding and structure, kinetics and reaction mechanisms, polymer research, analysis and synthesis. (5). Biology, - structure and dynamics of biological macromolecules, membrane and cell biology. (6) Development of methods and instruments - neutron sources, synchrotron sources, special accelerators, research with interlinked systems and devices. (orig.) [de

Inverse operator theory method and its applications in nonlinear physics

International Nuclear Information System (INIS)

Fang Jinqing

1993-01-01

Inverse operator theory method, which has been developed by G. Adomian in recent years, and its applications in nonlinear physics are described systematically. The method can be an unified effective procedure for solution of nonlinear and/or stochastic continuous dynamical systems without usual restrictive assumption. It is realized by Mathematical Mechanization by us. It will have a profound on the modelling of problems of physics, mathematics, engineering, economics, biology, and so on. Some typical examples of the application are given and reviewed

Normal mode analysis and applications in biological physics.

Science.gov (United States)

Dykeman, Eric C; Sankey, Otto F

2010-10-27

Normal mode analysis has become a popular and often used theoretical tool in the study of functional motions in enzymes, viruses, and large protein assemblies. The use of normal modes in the study of these motions is often extremely fruitful since many of the functional motions of large proteins can be described using just a few normal modes which are intimately related to the overall structure of the protein. In this review, we present a broad overview of several popular methods used in the study of normal modes in biological physics including continuum elastic theory, the elastic network model, and a new all-atom method, recently developed, which is capable of computing a subset of the low frequency vibrational modes exactly. After a review of the various methods, we present several examples of applications of normal modes in the study of functional motions, with an emphasis on viral capsids.

Dielectric relaxation in biological systems physical principles, methods, and applications

CERN Document Server

Feldman, Yuri

2015-01-01

This title covers the theoretical basis and practical aspects of the study of dielectric properties of biological systems, such as water, electrolyte and polyelectrolytes, solutions of biological macromolecules, cells suspensions and cellular systems.

Physical integrity: the missing link in biological monitoring and TMDLs.

Science.gov (United States)

Asmus, Brenda; Magner, Joseph A; Vondracek, Bruce; Perry, Jim

2009-12-01

The Clean Water Act mandates that the chemical, physical, and biological integrity of our nation's waters be maintained and restored. Physical integrity has often been defined as physical habitat integrity, and as such, data collected during biological monitoring programs focus primarily on habitat quality. However, we argue that channel stability is a more appropriate measure of physical integrity and that channel stability is a foundational element of physical habitat integrity in low-gradient alluvial streams. We highlight assessment tools that could supplement stream assessments and the Total Maximum Daily Load stressor identification process: field surveys of bankfull cross-sections; longitudinal thalweg profiles; particle size distribution; and regionally calibrated, visual, stream stability assessments. Benefits of measuring channel stability include a more informed selection of reference or best attainable stream condition for an Index of Biotic Integrity, establishment of a baseline for monitoring changes in present and future condition, and indication of channel stability for investigations of chemical and biological impairments associated with sediment discontinuity and loss of habitat quality.

Research at the interface of physics and biology: bridging the two fields

Science.gov (United States)

Shukla, Kamal

2014-10-01

I firmly believe that interaction between physics and biology is not only natural, but inevitable. Kamal Shukla provides a personal perspective on working at the interface between the physical and biological sciences.

Getting the measure of things: the physical biology of stem cells.

Science.gov (United States)

Lowell, Sally

2013-10-01

In July 2013, the diverse fields of biology, physics and mathematics converged to discuss 'The Physical Biology of Stem Cells', the subject of the third annual symposium of the Cambridge Stem Cell Institute, UK. Two clear themes resonated throughout the meeting: the new insights gained from advances in the acquisition and interpretation of quantitative data; and the importance of 'thinking outside the nucleus' to consider physical influences on cell fate.

Breaking Frontiers: Submicron Structures in Physics and Biology - 52 Zakopane School of Physics

International Nuclear Information System (INIS)

2008-01-01

The 52 Zakopane School of Physics held in Zakopane from 19 to 24 May 2008. The main task of the symposium was to present the newest results of research in field of submicron structures in physics, biology and medicine. Some new technologies as well as their applications are also presented

Breaking Frontiers: Submicron Structures in Physics and Biology - 52 Zakopane School of Physics

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

The 52 Zakopane School of Physics held in Zakopane from 19 to 24 May 2008. The main task of the symposium was to present the newest results of research in field of submicron structures in physics, biology and medicine. Some new technologies as well as their applications are also presented.

Introduction to solitons and their applications in physics and biology

International Nuclear Information System (INIS)

Peyrard, M.

1995-01-01

The response of most of the physical systems to combined excitations is not a simple superposition of their response to individual stimuli. This is particularly true for biological systems in which the nonlinear effects are often the dominant ones. The intrinsic treatment of nonlinearities in mathematical models and physical systems has led to the emergence of the chaos and solitons concepts. The concept of soliton, relevant for systems with many degrees of freedom, provides a new tool in the studies of biomolecules because it has no equivalent in the world of linear excitations. The aim of this lecture is to present the main ideas that underline the soliton concept and to discuss some applications. Solitons are solitary waves, that propagate at constant speed without changing their shape. They are extremely stable to perturbations, in particular to collisions with small amplitude linear waves and with other solitons. Conditions to have solitons and equations of solitons propagation are analysed. Solitons can be divided into two main classes: topological and non-topological solitons which can be found at all scales and in various domains of physics and chemistry. Using simple examples, this paper shows how linear expansions can miss completely essential physical properties of a system. This is particularly characteristic for the pendulum chain example. Soliton theory offers alternative methods. Multiple scale approximations, or expansion on a soliton basis, can be very useful to provide a description of some physical phenomena. Nonlinear energy localization is also a very important concept valid for a large variety of systems. These concepts are probably even more relevant for biological molecules than for solid state physics, because these molecules are very deformable objects where large amplitude nonlinear motions or conformational changes are crucial for function. (J.S.). 14 refs., 9 figs

Simulating biological processes: stochastic physics from whole cells to colonies

Science.gov (United States)

Earnest, Tyler M.; Cole, John A.; Luthey-Schulten, Zaida

2018-05-01

The last few decades have revealed the living cell to be a crowded spatially heterogeneous space teeming with biomolecules whose concentrations and activities are governed by intrinsically random forces. It is from this randomness, however, that a vast array of precisely timed and intricately coordinated biological functions emerge that give rise to the complex forms and behaviors we see in the biosphere around us. This seemingly paradoxical nature of life has drawn the interest of an increasing number of physicists, and recent years have seen stochastic modeling grow into a major subdiscipline within biological physics. Here we review some of the major advances that have shaped our understanding of stochasticity in biology. We begin with some historical context, outlining a string of important experimental results that motivated the development of stochastic modeling. We then embark upon a fairly rigorous treatment of the simulation methods that are currently available for the treatment of stochastic biological models, with an eye toward comparing and contrasting their realms of applicability, and the care that must be taken when parameterizing them. Following that, we describe how stochasticity impacts several key biological functions, including transcription, translation, ribosome biogenesis, chromosome replication, and metabolism, before considering how the functions may be coupled into a comprehensive model of a ‘minimal cell’. Finally, we close with our expectation for the future of the field, focusing on how mesoscopic stochastic methods may be augmented with atomic-scale molecular modeling approaches in order to understand life across a range of length and time scales.

Physical methods in air pollution research: The second decade

International Nuclear Information System (INIS)

Cahill, T.A.

1985-01-01

The ''Second Decade'' in the application of physical techniques to air pollution has been a profound change in the understanding and capabilities. A great deal remains to be done with the new tools. But what about the next phase? The author feels that it will probably involve greater chemical and biological emphasis, as opposed to merely elemental analysis. But this will not be easy, and one will again need an influx of new people and ideas into the field, most likely from the biological, organic chemical, and medical communities. The author predicts that because of the inherent complexity of the problem, it will not happen in just 10 years. In the meantime, one will somehow manage to keep busy rediscovering atmospheric aerosols yet again, but with the new eyes the improved physical methods have gained

Biological/Genetic Regulation of Physical Activity Level: Consensus from GenBioPAC.

Science.gov (United States)

Lightfoot, J Timothy; DE Geus, Eco J C; Booth, Frank W; Bray, Molly S; DEN Hoed, Marcel; Kaprio, Jaakko; Kelly, Scott A; Pomp, Daniel; Saul, Michael C; Thomis, Martine A; Garland, Theodore; Bouchard, Claude

2018-04-01

Physical activity unquestionably maintains and improves health; however, physical activity levels globally are low and not rising despite all the resources devoted to this goal. Attention in both the research literature and the public policy domain has focused on social-behavioral factors; however, a growing body of literature suggests that biological determinants play a significant role in regulating physical activity levels. For instance, physical activity level, measured in various manners, has a genetic component in both humans and nonhuman animal models. This consensus article, developed as a result of an American College of Sports Medicine-sponsored round table, provides a brief review of the theoretical concepts and existing literature that supports a significant role of genetic and other biological factors in the regulation of physical activity. Future research on physical activity regulation should incorporate genetics and other biological determinants of physical activity instead of a sole reliance on social and other environmental determinants.

Conference: Statistical Physics and Biological Information

International Nuclear Information System (INIS)

Gross, David J.; Hwa, Terence

2001-01-01

In the spring of 2001, the Institute for Theoretical Physics ran a 6 month scientific program on Statistical Physics and Biological Information. This program was organized by Walter Fitch (UC Irvine), Terence Hwa (UC San Diego), Luca Peliti (University Federico II), Naples Gary Stormo (Washington University School of Medicine) and Chao Tang (NEC). Overall scientific supervision was provided by David Gross, Director, ITP. The ITP has an online conference/program proceeding which consists of audio and transparencies of almost all of the talks held during this program. Over 100 talks are available on the site at http://online.kitp.ucsb.edu/online/infobio01/

Perspectives on theory at the interface of physics and biology

Science.gov (United States)

Bialek, William

2018-01-01

Theoretical physics is the search for simple and universal mathematical descriptions of the natural world. In contrast, much of modern biology is an exploration of the complexity and diversity of life. For many, this contrast is prima facie evidence that theory, in the sense that physicists use the word, is impossible in a biological context. For others, this contrast serves to highlight a grand challenge. I am an optimist, and believe (along with many colleagues) that the time is ripe for the emergence of a more unified theoretical physics of biological systems, building on successes in thinking about particular phenomena. In this essay I try to explain the reasons for my optimism, through a combination of historical and modern examples.

Ionising radiation - physical and biological effects

International Nuclear Information System (INIS)

Holter, Oe.; Ingebretsen, F.; Parr, H.

1979-01-01

The physics of ionising radiation is briefly presented. The effects of ionising radiation on biological cells, cell repair and radiosensitivity are briefly treated, where after the effects on man and mammals are discussed and related to radiation doses. Dose limits are briefly discussed. The genetic effects are discussed separately. Radioecology is also briefly treated and a table of radionuclides deriving from reactors, and their radiation is given. (JIW)

Simbios: an NIH national center for physics-based simulation of biological structures.

Science.gov (United States)

Delp, Scott L; Ku, Joy P; Pande, Vijay S; Sherman, Michael A; Altman, Russ B

2012-01-01

Physics-based simulation provides a powerful framework for understanding biological form and function. Simulations can be used by biologists to study macromolecular assemblies and by clinicians to design treatments for diseases. Simulations help biomedical researchers understand the physical constraints on biological systems as they engineer novel drugs, synthetic tissues, medical devices, and surgical interventions. Although individual biomedical investigators make outstanding contributions to physics-based simulation, the field has been fragmented. Applications are typically limited to a single physical scale, and individual investigators usually must create their own software. These conditions created a major barrier to advancing simulation capabilities. In 2004, we established a National Center for Physics-Based Simulation of Biological Structures (Simbios) to help integrate the field and accelerate biomedical research. In 6 years, Simbios has become a vibrant national center, with collaborators in 16 states and eight countries. Simbios focuses on problems at both the molecular scale and the organismal level, with a long-term goal of uniting these in accurate multiscale simulations.

Coordinating an IPLS class with a biology curriculum: NEXUS/Physics

Science.gov (United States)

Redish, Edward

2014-03-01

A multi-disciplinary team of scientists has been reinventing the Introductory Physics for Life Scientists (IPLS) course at the University of Maryland. We focus on physics that connects elements common to the curriculum for all life scientists - molecular and cellular biology - with building general scientific competencies, such as mathematical modeling, reasoning from core principles, and multi-representation translation. The prerequisites for the class include calculus, chemistry, and biology. In addition to building the basic ideas of the Newtonian framework, electric currents, and optics, our prerequisites allow us to include topics such as atomic interactions and chemical bonding, random motion and diffusion, thermodynamics (including entropy and free energy), and spectroscopy. Our chemical bonding unit helps students link the view of energy developed in traditional macroscopic physics with the idea of chemical bonding as a source of energy presented in their chemistry and biology classes. Education research has played a central role in our design, as has a strong collaboration between our Discipline-Based Education and the Biophysics Research groups. These elements permit us to combine modern pedagogy with cutting-edge insights into the physics of living systems. Supported in part by a grant from HHMI and the US NSF grant #1122818/.

Mathematical methods in biology and neurobiology

CERN Document Server

Jost, Jürgen

2014-01-01

Mathematical models can be used to meet many of the challenges and opportunities offered by modern biology. The description of biological phenomena requires a range of mathematical theories. This is the case particularly for the emerging field of systems biology. Mathematical Methods in Biology and Neurobiology introduces and develops these mathematical structures and methods in a systematic manner. It studies:   • discrete structures and graph theory • stochastic processes • dynamical systems and partial differential equations • optimization and the calculus of variations.   The biological applications range from molecular to evolutionary and ecological levels, for example:   • cellular reaction kinetics and gene regulation • biological pattern formation and chemotaxis • the biophysics and dynamics of neurons • the coding of information in neuronal systems • phylogenetic tree reconstruction • branching processes and population genetics • optimal resource allocation • sexual recombi...

Advances in Physical and Biological Radiation Detectors. Proceedings of a Symposium on New Developments in Physical and Biological Radiation Detectors

International Nuclear Information System (INIS)

1971-01-01

Radiation dosimetry is a fundamental part of all radiation protection work. The measurements are made with a variety of instruments, and health physicists, after professional interpretation of the data, can assess the levels of exposure which might be encountered in a given area or the individual doses received by workers, visitors and others at places where the possibility of radiation exposure exists. The types of radiation concerned here are photon radiations, ranging from soft X-rays to gamma rays, and particulate radiations such as β-rays, α-particles, protons, neutrons and fission fragments. The type of technique used depends not only on the type of radiation but also on such factors as whether the radiation is from a source internal or external to the body. Radiation dosimetry is not only used at nuclear facilities; it has diverse applications, for example in determining doses when radiation sources are employed for medical diagnostics and therapy, in safeguarding workers in any industry where isotopes are used, and in assessing the effect of both naturally occurring and man-made radiations on the general public and the environment. The advances of modern technology have increased the variety of sources; an example can be given from colour television, where the high potential necessary in certain colour cathode-ray tubes generates a non-negligible amount of X-rays. The Symposium on New Developments in Physical and Biological Radiation Detectors was one of a continuing series of meetings in which the International Atomic Energy Agency furthers the exchange of information on all aspects of personnel and area dosimetry. The Symposium was devoted in particular to a study of the dose meters themselves - their radiation-sensitive elements (both physical and biological),their instrumentation, and calibration and standardization. Several speakers suggested that the situation in the standardization and calibration of measuring equipment and sources was

Bringing the physical sciences into your cell biology research.

Science.gov (United States)

Robinson, Douglas N; Iglesias, Pablo A

2012-11-01

Historically, much of biology was studied by physicists and mathematicians. With the advent of modern molecular biology, a wave of researchers became trained in a new scientific discipline filled with the language of genes, mutants, and the central dogma. These new molecular approaches have provided volumes of information on biomolecules and molecular pathways from the cellular to the organismal level. The challenge now is to determine how this seemingly endless list of components works together to promote the healthy function of complex living systems. This effort requires an interdisciplinary approach by investigators from both the biological and the physical sciences.

Radiations at the physics-biology interface. Utilization of radiations for research

International Nuclear Information System (INIS)

Douzou, P.

1997-01-01

Structural biology, which study the relation between the structure of biomolecules and their function, is at the interface between physics and biology. With the help of large radiation instruments such as X ray diffraction and neutron scattering, important advancements have been accomplished in the understanding of specific biological functions and led to the development of protein engineering (such as directed mutagenesis)

Assessment of refinery effluents and receiving waters using biologically-based effect methods

International Nuclear Information System (INIS)

2012-01-01

Within the EU it is apparent that the regulatory focus on the use of biologically-based effects methods in the assessment of refinery effluents and receiving waters has increased in the past decade. This has been reflected in a recent refinery survey which revealed an increased use of such methods for assessing the quality of refinery effluents and their receiving waters. This report provides an overview of recent techniques used for this purpose. Several case studies provided by CONCAWE member companies describe the application of biological methods to effluent discharge assessment and surface water monitoring. The case studies show that when biological methods are applied to refinery effluents and receiving waters they raise different questions compared with those obtained using physical and chemical methods. Although direct measurement of the toxicity of effluent and receiving to aquatic organisms is the most cited technique, more recent efforts include tests that also address the persistence of effluent toxicity once discharged into the receiving water. Similarly, ecological monitoring of receiving waters can identify effects of effluent inputs arising from species interactions and other secondary effects that would not always be apparent from the results of biological tests conducted on single aquatic organisms. In light of recent and proposed regulatory developments the objectives of this report are therefore to: Discuss the application of biologically-based effects methods (including ecological monitoring) to refinery discharges and receiving waters; Assess the implications of such methods for future regulation of refinery discharges; and Provide guidance on good practice that can be used by refineries and the downstream oil industry to carry out and interpret data obtained using biologically-based effects methods. While the emphasis is on the toxic effects of effluents, other properties will also be covered because of their interdependency in determining

Assessment of refinery effluents and receiving waters using biologically-based effect methods

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-01-15

Within the EU it is apparent that the regulatory focus on the use of biologically-based effects methods in the assessment of refinery effluents and receiving waters has increased in the past decade. This has been reflected in a recent refinery survey which revealed an increased use of such methods for assessing the quality of refinery effluents and their receiving waters. This report provides an overview of recent techniques used for this purpose. Several case studies provided by CONCAWE member companies describe the application of biological methods to effluent discharge assessment and surface water monitoring. The case studies show that when biological methods are applied to refinery effluents and receiving waters they raise different questions compared with those obtained using physical and chemical methods. Although direct measurement of the toxicity of effluent and receiving to aquatic organisms is the most cited technique, more recent efforts include tests that also address the persistence of effluent toxicity once discharged into the receiving water. Similarly, ecological monitoring of receiving waters can identify effects of effluent inputs arising from species interactions and other secondary effects that would not always be apparent from the results of biological tests conducted on single aquatic organisms. In light of recent and proposed regulatory developments the objectives of this report are therefore to: Discuss the application of biologically-based effects methods (including ecological monitoring) to refinery discharges and receiving waters; Assess the implications of such methods for future regulation of refinery discharges; and Provide guidance on good practice that can be used by refineries and the downstream oil industry to carry out and interpret data obtained using biologically-based effects methods. While the emphasis is on the toxic effects of effluents, other properties will also be covered because of their interdependency in determining

Helium ions for radiotherapy? Physical and biological verifications of a novel treatment modality

Energy Technology Data Exchange (ETDEWEB)

Krämer, Michael, E-mail: m.kraemer@gsi.de; Scifoni, Emanuele; Schuy, Christoph; Rovituso, Marta; Maier, Andreas; Kaderka, Robert; Kraft-Weyrather, Wilma [Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Tinganelli, Walter; Durante, Marco [Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany and Trento Institute for Fundamental Physics and Application (TIFPA-INFN), 38123, via Sommarive 14, Trento (Italy); Brons, Stephan; Tessonnier, Thomas [Heidelberger Ionenstrahl-Therapiezentrum (HIT), Im Neuenheimer Feld 450, 69120 Heidelberg, Germany and Radioonkologie und Strahlentherapie, Universitätsklinikums Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Parodi, Katia [Heidelberger Ionenstrahl-Therapiezentrum (HIT), Im Neuenheimer Feld 450, 69120 Heidelberg (Germany); Radioonkologie und Strahlentherapie, Universitätsklinikums Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Ludwig-Maximilians-Universitaet Muenchen (LMU Munich), Department of Medical Physics, Am Coulombwall 1, 85748 Munich (Germany)

2016-04-15

Purpose: Modern facilities for actively scanned ion beam radiotherapy allow in principle the use of helium beams, which could present specific advantages, especially for pediatric tumors. In order to assess the potential use of these beams for radiotherapy, i.e., to create realistic treatment plans, the authors set up a dedicated {sup 4}He beam model, providing base data for their treatment planning system TRiP98, and they have reported that in this work together with its physical and biological validations. Methods: A semiempirical beam model for the physical depth dose deposition and the production of nuclear fragments was developed and introduced in TRiP98. For the biological effect calculations the last version of the local effect model was used. The model predictions were experimentally verified at the HIT facility. The primary beam attenuation and the characteristics of secondary charged particles at various depth in water were investigated using {sup 4}He ion beams of 200 MeV/u. The nuclear charge of secondary fragments was identified using a ΔE/E telescope. 3D absorbed dose distributions were measured with pin point ionization chambers and the biological dosimetry experiments were realized irradiating a Chinese hamster ovary cells stack arranged in an extended target. Results: The few experimental data available on basic physical processes are reproduced by their beam model. The experimental verification of absorbed dose distributions in extended target volumes yields an overall agreement, with a slight underestimation of the lateral spread. Cell survival along a 4 cm extended target is reproduced with remarkable accuracy. Conclusions: The authors presented a simple simulation model for therapeutical {sup 4}He beams which they introduced in TRiP98, and which is validated experimentally by means of physical and biological dosimetries. Thus, it is now possible to perform detailed treatment planning studies with {sup 4}He beams, either exclusively or in

Conference: Statistical Physics and Biological Information; F

International Nuclear Information System (INIS)

Gross, David J.; Hwa, Terence

2001-01-01

In the spring of 2001, the Institute for Theoretical Physics ran a 6 month scientific program on Statistical Physics and Biological Information. This program was organized by Walter Fitch (UC Irvine), Terence Hwa (UC San Diego), Luca Peliti (University Federico II), Naples Gary Stormo (Washington University School of Medicine) and Chao Tang (NEC). Overall scientific supervision was provided by David Gross, Director, ITP. The ITP has an online conference/program proceeding which consists of audio and transparencies of almost all of the talks held during this program. Over 100 talks are available on the site at http://online.kitp.ucsb.edu/online/infobio01/

The Cytoskeleton: Mechanical, Physical, and Biological Interactions

Science.gov (United States)

1996-01-01

This workshop, entitled "The Cytoskeleton: Mechanical, Physical, and Biological Interactions," was sponsored by the Center for Advanced Studies in the Space Life Sciences at the Marine Biological Laboratory. This Center was established through a cooperative agreement between the MBL and the Life Sciences Division of the National Aeronautics and Space Administration. To achieve these goals, the Center sponsors a series of workshops on various topics in the life sciences. Elements of the cytoskeleton have been implicated in the effects of gravity on the growth of plants fungi. An intriguing finding in this regard is the report indicating that an integrin-like protein may be the gravireceptor in the internodal cells of Chara. Involvement of the cytoskeleton in cellular graviperception of the basidiomycete Flammulina velutipes has also been reported. Although the responses of mammalian cells to gravity are not well documented, it has been proposed that integrins can act as mechanochemical transducers in mammalian cells. Little is known about the integrated mechanical and physical properties of cytoplasm, this workshop would be the best place to begin developing interdisciplinary approaches to the effects of mechanical stresses on cells and their most likely responsive cytoplasmic elements- the fibrous proteins comprising the cytoskeleton.

Physical and biological factors determining the effective proton range

International Nuclear Information System (INIS)

Grün, Rebecca; Friedrich, Thomas; Krämer, Michael; Scholz, Michael; Zink, Klemens; Durante, Marco; Engenhart-Cabillic, Rita

2013-01-01

Purpose: Proton radiotherapy is rapidly becoming a standard treatment option for cancer. However, even though experimental data show an increase of the relative biological effectiveness (RBE) with depth, particularly at the distal end of the treatment field, a generic RBE of 1.1 is currently used in proton radiotherapy. This discrepancy might affect the effective penetration depth of the proton beam and thus the dose to the surrounding tissue and organs at risk. The purpose of this study was thus to analyze the impact of a tissue and dose dependent RBE of protons on the effective range of the proton beam in comparison to the range based on a generic RBE of 1.1.Methods: Factors influencing the biologically effective proton range were systematically analyzed by means of treatment planning studies using the Local Effect Model (LEM IV) and the treatment planning software TRiP98. Special emphasis was put on the comparison of passive and active range modulation techniques.Results: Beam energy, tissue type, and dose level significantly affected the biological extension of the treatment field at the distal edge. Up to 4 mm increased penetration depth as compared to the depth based on a constant RBE of 1.1. The extension of the biologically effective range strongly depends on the initial proton energy used for the most distal layer of the field and correlates with the width of the distal penumbra. Thus, the range extension, in general, was more pronounced for passive as compared to active range modulation systems, whereas the maximum RBE was higher for active systems.Conclusions: The analysis showed that the physical characteristics of the proton beam in terms of the width of the distal penumbra have a great impact on the RBE gradient and thus also the biologically effective penetration depth of the beam

An introduction to nuclear physics, with applications in medicine and biology

International Nuclear Information System (INIS)

Dyson, N.A.

1981-01-01

A concise account of the applications of nuclear physics to medical and biological science is given. Half the book is devoted to the basic aspects of nuclear and radiation physics such as interactions between radiation and matter, nuclear reactions and the production of isotopes, an introduction to α, β and γ-radiation detectors and finally the radiation from nuclear decay. Information is then given on the applications of radioisotopes and neutrons and other accelerator-based applications in medicine and biology. The book is aimed at not only those undergraduates and postgraduates who are devoting their main effort to medical physics, but also to those students who are looking primarily for an introduction to nuclear physics together with an account of some of the ways in which it impinges on the work of other scientists. (U.K.)

Isobio software: biological dose distribution and biological dose volume histogram from physical dose conversion using linear-quadratic-linear model.

Science.gov (United States)

Jaikuna, Tanwiwat; Khadsiri, Phatchareewan; Chawapun, Nisa; Saekho, Suwit; Tharavichitkul, Ekkasit

2017-02-01

To develop an in-house software program that is able to calculate and generate the biological dose distribution and biological dose volume histogram by physical dose conversion using the linear-quadratic-linear (LQL) model. The Isobio software was developed using MATLAB version 2014b to calculate and generate the biological dose distribution and biological dose volume histograms. The physical dose from each voxel in treatment planning was extracted through Computational Environment for Radiotherapy Research (CERR), and the accuracy was verified by the differentiation between the dose volume histogram from CERR and the treatment planning system. An equivalent dose in 2 Gy fraction (EQD 2 ) was calculated using biological effective dose (BED) based on the LQL model. The software calculation and the manual calculation were compared for EQD 2 verification with pair t -test statistical analysis using IBM SPSS Statistics version 22 (64-bit). Two and three-dimensional biological dose distribution and biological dose volume histogram were displayed correctly by the Isobio software. Different physical doses were found between CERR and treatment planning system (TPS) in Oncentra, with 3.33% in high-risk clinical target volume (HR-CTV) determined by D 90% , 0.56% in the bladder, 1.74% in the rectum when determined by D 2cc , and less than 1% in Pinnacle. The difference in the EQD 2 between the software calculation and the manual calculation was not significantly different with 0.00% at p -values 0.820, 0.095, and 0.593 for external beam radiation therapy (EBRT) and 0.240, 0.320, and 0.849 for brachytherapy (BT) in HR-CTV, bladder, and rectum, respectively. The Isobio software is a feasible tool to generate the biological dose distribution and biological dose volume histogram for treatment plan evaluation in both EBRT and BT.

Comparison of Technology Use between Biology and Physics Teachers in a 1:1 Laptop Environment

Science.gov (United States)

Crook, Simon J.; Sharma, Manjula D.; Wilson, Rachel

2015-01-01

Using a mixed-methods approach the authors compared the associated practices of senior physics teachers (n = 7) and students (n = 53) in a 1:1 laptop environment with those of senior biology teachers (n = 10) and students (n = 125) also in a 1:1 laptop environment, in seven high schools in Sydney, NSW, Australia. They found that the physics…

Physics and the molecular revolution in plant biology: union needed for managing the future

Directory of Open Access Journals (Sweden)

Ulrich Lüttge

2016-10-01

Full Text Available The question was asked if there is still a prominent role of biophysics in plant biology in an age when molecular biology appears to be dominating. Mathematical formation of theory is essential in systems biology, and mathematics is more inherent in biophysics than in molecular biology. A survey is made identifying and briefly characterizing fields of plant biology where approaches of biophysics remain essential. In transport at membranes electrophysiology and thermodynamics are biophysical topics. Water is a special molecule. Its transport follows the physical laws of osmosis and gradients of water potential on the background of physics of hydraulic architecture. Photobiology needs understanding of the physics of electro-magnetic radiation of quantitative nature in photosynthesis and of qualitative nature in perception by the photo-sensors cryptochromes, phototropins and phytochrome in environmental responses and development. Biophysical oscillators can play a role in biological timing by the circadian clock. Integration in the self-organization of modules, such as roots, stems and leaves, for the emergence of whole plants as unitary organisms needs storage and transport of information where physical modes of signaling are essential with cross talks between electrical and hydraulic signals and with chemical signals. Examples are gravitropism and root-shoot interactions in water relations. All of these facets of plant biophysics overlie plant molecular biology and exchange with it. It is advocated that a union of approaches of plant molecular biology and biophysics needs to be cultivated. In many cases it is already operative. In bionics biophysics is producing output for practical applications linking biology with technology. Biomimetic engineering intrinsically uses physical approaches. An extreme biophysical perspective is looking out for life in space. Sustained and increased practice of biophysics with teaching and research deserves strong

Interface between Physics and Biology: Training a New Generation of Creative Bilingual Scientists.

Science.gov (United States)

Riveline, Daniel; Kruse, Karsten

2017-08-01

Whereas physics seeks for universal laws underlying natural phenomena, biology accounts for complexity and specificity of molecular details. Contemporary biological physics requires people capable of working at this interface. New programs prepare scientists who transform respective disciplinary views into innovative approaches for solving outstanding problems in the life sciences. Copyright © 2017 Elsevier Ltd. All rights reserved.

Future directions for radiological physics: An interface with molecular biology

International Nuclear Information System (INIS)

Braby, L.A.

1987-01-01

Recent experiments with low energy x-rays and fast molecular ions have shown that the products of the interaction of several ionizations within a few nanometers dominate radiation effects. However, the authors still can only make assumptions about the physical and chemical nature of this initial damage. Enzymatic repair of DNA damage is another key factor, but they have little idea of what governs the success or failure (misrepair) of these processes. Unresolved problems like these dictate the future direction of radiological physics. Molecular biology techniques are being applied to determine molecular alterations which result in observed damage. Interpretation of these experiments will require new data on the physics of energy transfer to macromolecules and the stochastics of energy deposition in time. Future studies will attempt to identify the initial damage, before biological processes have amplified it. This will require a detailed understanding of the role of chromatin structure in governing gene expression, the transport of energy within macromolecules, the transport of ions and radicals in the semiordered environment near DNA strands, and many other physical characteristics within the living cell

Uncovering the underlying physical mechanisms of biological systems via quantification of landscape and flux

International Nuclear Information System (INIS)

Xu Li; Chu Xiakun; Yan Zhiqiang; Zheng Xiliang; Zhang Kun; Zhang Feng; Yan Han; Wu Wei; Wang Jin

2016-01-01

In this review, we explore the physical mechanisms of biological processes such as protein folding and recognition, ligand binding, and systems biology, including cell cycle, stem cell, cancer, evolution, ecology, and neural networks. Our approach is based on the landscape and flux theory for nonequilibrium dynamical systems. This theory provides a unifying principle and foundation for investigating the underlying mechanisms and physical quantification of biological systems. (topical review)

Biological mechanisms underlying the role of physical fitness in health and resilience

OpenAIRE

Silverman, Marni N.; Deuster, Patricia A.

2014-01-01

Physical fitness, achieved through regular exercise and/or spontaneous physical activity, confers resilience by inducing positive psychological and physiological benefits, blunting stress reactivity, protecting against potentially adverse behavioural and metabolic consequences of stressful events and preventing many chronic diseases. In this review, we discuss the biological mechanisms underlying the beneficial effects of physical fitness on mental and physical health. Physical fitness appear...

The Effects Of Physical And Biological Cohesion On Bedforms

Science.gov (United States)

Parsons, D. R.; Schindler, R.; Baas, J.; Hope, J. A.; Malarkey, J.; Paterson, D. M.; Peakall, J.; Manning, A. J.; Ye, L.; Aspden, R.; Alan, D.; Bass, S. J.

2014-12-01

Most coastal sediments consist of complex mixtures of cohesionless sands, physically-cohesive clays and extra cellular polymeric substances (EPS) that impart biological cohesion. Yet, our ability to predict bedform dimensions in these substrates is reliant on predictions based exclusively on cohesionless sand. We present findings from the COHBED project - which explicitly examines how bedform dynamics are modified by natural cohesion. Our experimental results show that for ripples, height and length are inversely proportional to initial clay content and bedforms take longer to appear, with no ripples when clay content exceeds 18%. When clay is replaced by EPS the development time and time of first appearance of ripples both increase by two orders of magnitude, with no bedforms above 0.125% EPS. For dunes, height and length are also inversely proportional to initial substrate clay content, resulting in a transition from dunes to ripples normally associated with velocity decreases. Addition of low EPS concentrations into the substrate results in yet smaller bedforms at the same clay contents and at high EPS concentrations, biological cohesion supersedes all electrostatic bonding, and bedform size is no longer related to mud content. The contrast in physical and biological cohesion effects on bedform development result from the disparity between inter-particle electrostatic bonding of clay particles and EPS grain coating and strands that physically link sediments together, which effects winnowing rates as bedforms evolve. These findings have wide ranging implications for bedform predictions in both modern and ancient environments. Coupling of biological and morphological processes not only requires an understanding of how bedform dimensions influence biota and habitat, but also how benthic species can modify bedform dimensions. Consideration of both aspects provides a means in which fluid dynamics, sediment transport and ecosystem energetics can be linked to yield

Scandium: its occurrence, chemistry, physics, metallurgy, biology, and technology

International Nuclear Information System (INIS)

Horovitz, C.T.

1975-01-01

This book describes the following aspects of scandium: discovery and history, occurrence in nature, geochemistry and mineralogy, chemical, physical and technological properties, fabrication and metallurgy, its biological significance and toxicology, and its uses. (Extensive references for each chapter)

DNA confinement in nanochannels: physics and biological applications

DEFF Research Database (Denmark)

Reisner, Walter; Pedersen, Jonas Nyvold; Austin, Robert H

2012-01-01

in nanochannels, creating a linear unscrolling of the genome along the channel for analysis. We will first review the fundamental physics of DNA nanochannel confinement—including the effect of varying ionic strength—and then discuss recent applications of these systems to genomic mapping. Apart from the intense...... direct assessment of the genome in its native state). In this review, we will discuss how the information contained in genomic-length single DNA molecules can be accessed via physical confinement in nanochannels. Due to self-avoidance interactions, DNA molecules will stretch out when confined...... biological interest in extracting linear sequence information from elongated DNA molecules, from a physics view these systems are fascinating as they enable probing of single-molecule conformation in environments with dimensions that intersect key physical length-scales in the 1 nm to 100μm range. (Some...

Biology and physics competencies for pre-health and other life sciences students.

Science.gov (United States)

Hilborn, Robert C; Friedlander, Michael J

2013-06-01

The recent report on the Scientific Foundations for Future Physicians (SFFP) and the revised Medical College Admissions Test (MCAT) reframe the preparation for medical school (and other health professional schools) in terms of competencies: what students should know and be able to do with that knowledge, with a strong emphasis on scientific inquiry and research skills. In this article, we will describe the thinking that went into the SFFP report and what it says about scientific and quantitative reasoning, focusing on biology and physics and the overlap between those fields. We then discuss how the SFFP report set the stage for the discussion of the recommendations for the revised MCAT, which will be implemented in 2015, again focusing the discussion on biology and physics. Based on that framework, we discuss the implications for undergraduate biology and physics education if students are to be prepared to demonstrate these competencies.

Time in physics and biology

Directory of Open Access Journals (Sweden)

BRUNO GÜNTHER

2004-01-01

Full Text Available In contrast with classical physics, particularly with Sir Isaac Newton, where time is a continuous function, generally valid, eternally and evenly flowing as an absolute time dimension, in the biological sciences, time is in essence of cyclical nature (physiological periodicities, where future passes to past through an infinitely thin boundary, the present. In addition, the duration of the present (DP leads to the so-called 'granulation of time' in living beings, so that by the fusion of two successive pictures of the world, which are not entirely similar, they attain the perception of 'movement,' both in the real world as well as in the sham-movement in the mass media (TV.

Biological-based and physical-based optimization for biological evaluation of prostate patient's plans

Science.gov (United States)

Sukhikh, E.; Sheino, I.; Vertinsky, A.

2017-09-01

Modern modalities of radiation treatment therapy allow irradiation of the tumor to high dose values and irradiation of organs at risk (OARs) to low dose values at the same time. In this paper we study optimal radiation treatment plans made in Monaco system. The first aim of this study was to evaluate dosimetric features of Monaco treatment planning system using biological versus dose-based cost functions for the OARs and irradiation targets (namely tumors) when the full potential of built-in biological cost functions is utilized. The second aim was to develop criteria for the evaluation of radiation dosimetry plans for patients based on the macroscopic radiobiological criteria - TCP/NTCP. In the framework of the study four dosimetric plans were created utilizing the full extent of biological and physical cost functions using dose calculation-based treatment planning for IMRT Step-and-Shoot delivery of stereotactic body radiation therapy (SBRT) in prostate case (5 fractions per 7 Gy).

8. International Conference on Pulse Investigations in Chemistry, Biology and Physics - PULS'2008. Abstracts

International Nuclear Information System (INIS)

2008-01-01

The Report comprises abstracts of 68 communications (oral and posters) presented during the 8. International Conference on Pulse Investigations in Chemistry, Biology and Physics - PULS'2008, held on September 6 - 12, 2008 in Cracow. Presentations cover a variety of research fields representing different fields of pulse radiolysis in chemistry, biology and physics

8. International Conference on Pulse Investigations in Chemistry, Biology and Physics - PULS'2008. Abstracts

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

The Report comprises abstracts of 68 communications (oral and posters) presented during the 8. International Conference on Pulse Investigations in Chemistry, Biology and Physics - PULS'2008, held on September 6 - 12, 2008 in Cracow. Presentations cover a variety of research fields representing different fields of pulse radiolysis in chemistry, biology and physics.

Use of Biological Methods in Criminology

OpenAIRE

Müllerová, Nikola

2014-01-01

Criminology is a science dealing with the protection of citizens and state from infringement. Criminology uses mostly biological or genetic methods for crime detection. Forensic traces which are collected by forensic experts on the scene are the key items of those methods. Forensic genetics is among the most important forensic subdisciplines. Forensic genetics uses DNA analysis for identification. The main aims of this study are description and importance of biological, anthropological and ge...

Quantum mechanical simulation methods for studying biological systems

International Nuclear Information System (INIS)

Bicout, D.; Field, M.

1996-01-01

Most known biological mechanisms can be explained using fundamental laws of physics and chemistry and a full understanding of biological processes requires a multidisciplinary approach in which all the tools of biology, chemistry and physics are employed. An area of research becoming increasingly important is the theoretical study of biological macromolecules where numerical experimentation plays a double role of establishing a link between theoretical models and predictions and allowing a quantitative comparison between experiments and models. This workshop brought researchers working on different aspects of the development and application of quantum mechanical simulation together, assessed the state-of-the-art in the field and highlighted directions for future research. Fourteen lectures (theoretical courses and specialized seminars) deal with following themes: 1) quantum mechanical calculations of large systems, 2) ab initio molecular dynamics where the calculation of the wavefunction and hence the energy and forces on the atoms for a system at a single nuclear configuration are combined with classical molecular dynamics algorithms in order to perform simulations which use a quantum mechanical potential energy surface, 3) quantum dynamical simulations, electron and proton transfer processes in proteins and in solutions and finally, 4) free seminars that helped to enlarge the scope of the workshop. (N.T.)

How Can We Improve Problem Solving in Undergraduate Biology? Applying Lessons from 30 Years of Physics Education Research

Science.gov (United States)

Hoskinson, A.-M.; Caballero, M. D.; Knight, J. K.

2013-01-01

If students are to successfully grapple with authentic, complex biological problems as scientists and citizens, they need practice solving such problems during their undergraduate years. Physics education researchers have investigated student problem solving for the past three decades. Although physics and biology problems differ in structure and content, the instructional purposes align closely: explaining patterns and processes in the natural world and making predictions about physical and biological systems. In this paper, we discuss how research-supported approaches developed by physics education researchers can be adopted by biologists to enhance student problem-solving skills. First, we compare the problems that biology students are typically asked to solve with authentic, complex problems. We then describe the development of research-validated physics curricula emphasizing process skills in problem solving. We show that solving authentic, complex biology problems requires many of the same skills that practicing physicists and biologists use in representing problems, seeking relationships, making predictions, and verifying or checking solutions. We assert that acquiring these skills can help biology students become competent problem solvers. Finally, we propose how biology scholars can apply lessons from physics education in their classrooms and inspire new studies in biology education research. PMID:23737623

How can we improve problem solving in undergraduate biology? Applying lessons from 30 years of physics education research.

Science.gov (United States)

Hoskinson, A-M; Caballero, M D; Knight, J K

2013-06-01

If students are to successfully grapple with authentic, complex biological problems as scientists and citizens, they need practice solving such problems during their undergraduate years. Physics education researchers have investigated student problem solving for the past three decades. Although physics and biology problems differ in structure and content, the instructional purposes align closely: explaining patterns and processes in the natural world and making predictions about physical and biological systems. In this paper, we discuss how research-supported approaches developed by physics education researchers can be adopted by biologists to enhance student problem-solving skills. First, we compare the problems that biology students are typically asked to solve with authentic, complex problems. We then describe the development of research-validated physics curricula emphasizing process skills in problem solving. We show that solving authentic, complex biology problems requires many of the same skills that practicing physicists and biologists use in representing problems, seeking relationships, making predictions, and verifying or checking solutions. We assert that acquiring these skills can help biology students become competent problem solvers. Finally, we propose how biology scholars can apply lessons from physics education in their classrooms and inspire new studies in biology education research.

The relative importance of physical and biological energy in landscape evolution

Science.gov (United States)

Turowski, J. M.; Schwanghart, W.

2017-12-01

Landscapes are formed by the interplay of uplift and geomorphic processes, including interacting and competing physical and biological processes. For example, roots re-inforce soil and thereby stabilize hillslopes and the canopy cover of the forest may mediate the impact of precipitation. Furthermore, plants and animals act as geomorphic agents, directly altering landscape response and dynamics by their actions: tree roots may crack rocks, thus changing subsurface water flows and exposing fresh material for denudation; fungi excrete acids that accelerate rates of chemical weathering, and burrowing animals displace soil and rocks while digging holes for shelter or in search of food. Energetically, landscapes can be viewed as open systems in which topography stores potential energy above a base level. Tectonic processes add energy to the system by uplift and mechanically altering rock properties. Especially in unvegetated regions, erosion and transport by wind can be an important geomorphic process. Advection of atmospheric moisture in high altitudes provides potential energy that is converted by water fluxes through catchments. At the same time, the conversion of solar energy through atmospheric and biological processes drives primary production of living organisms. If we accept that biota influence geomorphic processes, then what is their energetic contribution to landscape evolution relative to physical processes? Using two case studies, we demonstrate that all components of energy input are negligible apart from biological production, quantified by net primary productivity (NPP) and potential energy conversion by water that is placed high up in the landscape as rainfall and leaves it as runoff. Assuming that the former is representative for biological energy and the latter for physical energy, we propose that the ratio of these two values can be used as a proxy for the relative importance of biological and physical processes in landscape evolution. All necessary

Robustness: confronting lessons from physics and biology.

Science.gov (United States)

Lesne, Annick

2008-11-01

The term robustness is encountered in very different scientific fields, from engineering and control theory to dynamical systems to biology. The main question addressed herein is whether the notion of robustness and its correlates (stability, resilience, self-organisation) developed in physics are relevant to biology, or whether specific extensions and novel frameworks are required to account for the robustness properties of living systems. To clarify this issue, the different meanings covered by this unique term are discussed; it is argued that they crucially depend on the kind of perturbations that a robust system should by definition withstand. Possible mechanisms underlying robust behaviours are examined, either encountered in all natural systems (symmetries, conservation laws, dynamic stability) or specific to biological systems (feedbacks and regulatory networks). Special attention is devoted to the (sometimes counterintuitive) interrelations between robustness and noise. A distinction between dynamic selection and natural selection in the establishment of a robust behaviour is underlined. It is finally argued that nested notions of robustness, relevant to different time scales and different levels of organisation, allow one to reconcile the seemingly contradictory requirements for robustness and adaptability in living systems.

Influence of different natural physical fields on biological processes

Science.gov (United States)

Mashinsky, A. L.

2001-01-01

In space flight conditions gravity, magnetic, and electrical fields as well as ionizing radiation change both in size, and in direction. This causes disruptions in the conduct of some physical processes, chemical reactions, and metabolism in living organisms. In these conditions organisms of different phylogenetic level change their metabolic reactions undergo changes such as disturbances in ionic exchange both in lower and in higher plants, changes in cell morphology for example, gyrosity in Proteus ( Proteus vulgaris), spatial disorientation in coleoptiles of Wheat ( Triticum aestivum) and Pea ( Pisum sativum) seedlings, mutational changes in Crepis ( Crepis capillaris) and Arabidopsis ( Arabidopsis thaliana) seedling. It has been found that even in the absence of gravity, gravireceptors determining spatial orientation in higher plants under terrestrial conditions are formed in the course of ontogenesis. Under weightlessness this system does not function and spatial orientation is determined by the light flux gradient or by the action of some other factors. Peculiarities of the formation of the gravireceptor apparatus in higher plants, amphibians, fish, and birds under space flight conditions have been observed. It has been found that the system in which responses were accompanied by phase transition have proven to be gravity-sensitive under microgravity conditions. Such reactions include also the process of photosynthesis which is the main energy production process in plants. In view of the established effects of microgravity and different natural physical fields on biological processes, it has been shown that these processes change due to the absence of initially rigid determination. The established biological effect of physical fields influence on biological processes in organisms is the starting point for elucidating the role of gravity and evolutionary development of various organisms on Earth.

Methods of experimental physics

CERN Document Server

Williams, Dudley

1962-01-01

Methods of Experimental Physics, Volume 3: Molecular Physics focuses on molecular theory, spectroscopy, resonance, molecular beams, and electric and thermodynamic properties. The manuscript first considers the origins of molecular theory, molecular physics, and molecular spectroscopy, as well as microwave spectroscopy, electronic spectra, and Raman effect. The text then ponders on diffraction methods of molecular structure determination and resonance studies. Topics include techniques of electron, neutron, and x-ray diffraction and nuclear magnetic, nuclear quadropole, and electron spin reson

Russian science readings (chemistry, physics, biology)

CERN Document Server

Light, L

1949-01-01

Some years' experience in teaching Russian to working scientists who had already acquired the rudiments of the grammar convinced me of the need for a reader of the present type that would smooth the path of those wishing to study Russian scientific literature in the original. Although the subject matter comprises what I have described for convenience as chemistry, physics and biology, it could be read with equal profit by those engaged in any branch of pure or applied science. All the passages are taken from school textbooks, and acknowledgements are due to the authors of the works listed at the foot of the contents page.

Designing and testing a classroom curriculum to teach preschoolers about the biology of physical activity: The respiration system as an underlying biological causal mechanism

Science.gov (United States)

Ewing, Tracy S.

The present study examined young children's understanding of respiration and oxygen as a source of vital energy underlying physical activity. Specifically, the purpose of the study was to explore whether a coherent biological theory, characterized by an understanding that bodily parts (heart and lungs) and processes (oxygen in respiration) as part of a biological system, can be taught as a foundational concept to reason about physical activity. The effects of a biology-based intervention curriculum designed to teach preschool children about bodily functions as a part of the respiratory system, the role of oxygen as a vital substance and how physical activity acts an energy source were examined. Participants were recruited from three private preschool classrooms (two treatment; 1 control) in Southern California and included a total of 48 four-year-old children (30 treatment; 18 control). Findings from this study suggested that young children could be taught relevant biological concepts about the role of oxygen in respiratory processes. Children who received biology-based intervention curriculum made significant gains in their understanding of the biology of respiration, identification of physical and sedentary activities. In addition these children demonstrated that coherence of conceptual knowledge was correlated with improved accuracy at activity identification and reasoning about the inner workings of the body contributing to endurance. Findings from this study provided evidence to support the benefits of providing age appropriate but complex coherent biological instruction to children in early childhood settings.

Radiation physics, biophysics, and radiation biology

International Nuclear Information System (INIS)

Hall, E.J.; Zaider, M.

1993-05-01

Research at the Center for Radiological Research is a multidisciplenary blend of physics, chemistry and biology aimed at understanding the mechanisms involved in the health problems resulting from human exposure to ionizing radiations. The focus is increased on biochemistry and the application of the techniques of molecular biology to the problems of radiation biology. Research highlights of the program from the past year are described. A mathematical model describing the production of single-strand and double-strand breaks in DNA as a function radiation quality has been completed. For the first time Monte Carlo techniques have been used to obtain directly the spatial distribution of DNA moieties altered by radiation. This information was obtained by including the transport codes a realistic description of the electronic structure of DNA. We have investigated structure activity relationships for the potential oncogenicity of a new generation of bioreductive drugs that function as hypoxic cytotoxins. Experimental and theoretical investigation of the inverse dose rate effect, whereby medium LET radiations actually produce an c effect when the dose is protracted, is now at a point where the basic mechanisms are reasonably understood and the complex interplay between dose, dose rate and radiation quality which is necessary for the effect to be present can now be predicted at least in vitro. In terms of early radiobiological damage, a quantitative link has been established between basic energy deposition and locally multiply damaged sites, the radiochemical precursor of DNA double strand breaks; specifically, the spatial and energy deposition requirements necessary to form LMDs have been evaluated. For the first time, a mechanically understood ''biological fingerprint'' of high-LET radiation has been established. Specifically measurement of the ratio of inter-to intra-chromosomal aberrations produces a unique signature from alpha-particles or neutrons

Radiation physics, biophysics, and radiation biology

Energy Technology Data Exchange (ETDEWEB)

Hall, E.J.; Zaider, M.

1993-05-01

Research at the Center for Radiological Research is a multidisciplenary blend of physics, chemistry and biology aimed at understanding the mechanisms involved in the health problems resulting from human exposure to ionizing radiations. The focus is increased on biochemistry and the application of the techniques of molecular biology to the problems of radiation biology. Research highlights of the program from the past year are described. A mathematical model describing the production of single-strand and double-strand breaks in DNA as a function radiation quality has been completed. For the first time Monte Carlo techniques have been used to obtain directly the spatial distribution of DNA moieties altered by radiation. This information was obtained by including the transport codes a realistic description of the electronic structure of DNA. We have investigated structure activity relationships for the potential oncogenicity of a new generation of bioreductive drugs that function as hypoxic cytotoxins. Experimental and theoretical investigation of the inverse dose rate effect, whereby medium LET radiations actually produce an c effect when the dose is protracted, is now at a point where the basic mechanisms are reasonably understood and the complex interplay between dose, dose rate and radiation quality which is necessary for the effect to be present can now be predicted at least in vitro. In terms of early radiobiological damage, a quantitative link has been established between basic energy deposition and locally multiply damaged sites, the radiochemical precursor of DNA double strand breaks; specifically, the spatial and energy deposition requirements necessary to form LMDs have been evaluated. For the first time, a mechanically understood biological fingerprint'' of high-LET radiation has been established. Specifically measurement of the ratio of inter-to intra-chromosomal aberrations produces a unique signature from alpha-particles or neutrons.

Mathematical methods in systems biology.

Science.gov (United States)

Kashdan, Eugene; Duncan, Dominique; Parnell, Andrew; Schattler, Heinz

2016-12-01

The editors of this Special Issue of Mathematical Biosciences and Engineering were the organizers for the Third International Workshop "Mathematical Methods in System Biology" that took place on June 15-18, 2015 at the University College Dublin in Ireland. As stated in the workshop goals, we managed to attract a good mix of mathematicians and statisticians working on biological and medical applications with biologists and clinicians interested in presenting their challenging problems and looking to find mathematical and statistical tools for their solutions.

Biological Methods and Manual Development

Science.gov (United States)

EPA scientists conduct research to develop and evaluate analytical methods for the identification, enumeration, evaluation of aquatic organisms exposed to environmental stressors and to correlate exposures with effects on chemical and biological indicators

Physical Activity: A Tool for Improving Health (Part 1--Biological Health Benefits)

Science.gov (United States)

Gallaway, Patrick J.; Hongu, Nobuko

2015-01-01

Extension educators have been promoting and incorporating physical activities into their community-based programs and improving the health of individuals, particularly those with limited resources. This article is the first of a three-part series describing the benefits of physical activity for human health: 1) biological health benefits of…

The Gravity of Regenerative Medicine; Physics, Chemistry & Biology behind it

Directory of Open Access Journals (Sweden)

Dedeepiya V

2008-01-01

Full Text Available The in-vitro expansion of cells of the organs/tissues and their re-implantation into the affected region/ tissue for treating cell/organ failure have been in practice for long, but in limited specialties. The in-vitro cell culture protocols use variety of biological reagents derived from animal sources and recombinant technologies. However, the optimal quantity of such biological components such as growth factors, cytokines etc.,needed for such cells to be grown in a non-physiological environment is still unknown. The use of such biological components have started to stir a controversy of late, due to the recognition of its potential hazards such as spread of prion diseases and contamination with non-human sialic acid proteins. Therefore synthetic reproducible biomaterials are gaining popularity in cell culture and tissue engineering. The biomaterials made of several chemical components based on physical parameters are starting to change certain concepts about the niche of cell culture and that of stem cell expansion and differentiation to specific lineages. Engler et al have already proven that a simple change in the matrix elasticity alone could change the lineage of the cells. Spencer et al have reported that a change in bioelectricity could change the morphogenesis during development. NCRM has been involved in cell culture and tissue engineering using approximately 240 different materials ranging from polymer hydrogel, gel with adherent inserts, nano composite materials, nano-coating technologies, nano-sheets and nano-films. These materials are used in cell culture in different hybrid combinations such as Floating 3D cell culture without adherent components in a homogenous hydrogel. Floating 3D cell culture with anchorage inserts. Flat surface- 2D adherent cell culture. Combined flat surface 2D cell culture (for differentiating cells and floating 3D culture (for undifferentiated cells. These combinations have started yielding several

Charge Migration in DNA Perspectives from Physics, Chemistry, and Biology

CERN Document Server

Chakraborty, Tapash

2007-01-01

Charge migration through DNA has been the focus of considerable interest in recent years. A deeper understanding of the nature of charge transfer and transport along the double helix is important in fields as diverse as physics, chemistry and nanotechnology. It has also important implications in biology, in particular in DNA damage and repair. This book presents contributions from an international team of researchers active in this field. It contains a wide range of topics that includes the mathematical background of the quantum processes involved, the role of charge transfer in DNA radiation damage, a new approach to DNA sequencing, DNA photonics, and many others. This book should be of value to researchers in condensed matter physics, chemical physics, physical chemistry, and nanoscale sciences.

Physical limits of feedback noise-suppression in biological networks

International Nuclear Information System (INIS)

Zhang, Jiajun; Yuan, Zhanjiang; Zhou, Tianshou

2009-01-01

Feedback is a ubiquitous control mechanism of biological networks, and has also been identified in a variety of regulatory systems and organisms. It has been shown that, for a given gain and with negligible intrinsic noise, negative feedback impairs noise buffering whereas positive feedback enhances noise buffering. We further investigate the influence of negative and positive feedback on noise in output signals by considering both intrinsic and extrinsic noise as well as operator noise. We find that, while maintaining the system sensitivity, either there exists a minimum of the output noise intensity corresponding to a biologically feasible feedback strength, or the output noise intensity is a monotonic function of feedback strength bounded by both biological and dynamical constraints. In both cases, feedback noise-suppression is physically limited. In other words, noise suppressed by negative or positive feedback cannot be reduced without limitation even in the case of slow transcription

Physical basis for biological effect

International Nuclear Information System (INIS)

Goodhead, D.T.

1987-01-01

Absorbed dose, or particle fluence, alone, are poor predictors of the biological effectiveness of ionizing radiations. Various radiation 'quality' parameters have been proposed to account quantitatively for the differences due to type of radiation. These include LET, quality factor (Q), lineal energy, specific energy and Z 2 /β 2 . However, all of these have major shortcomings, largely because they fail to describe adequately the microscopic stochastic properties of radiation which are primarily responsible for their relative effectiveness. Most biophysical models of radiation action now agree that the biological effectiveness of radiations are to a large extent determined by their very localized spatial properties of energy deposition (perhaps DNA and associated structures) and that the probability of residual permanent cellular damage (after cellular repair) depends on the nature of this initial macromolecular damage. Common features of these models make it clear that major future advances in identifying critical physical parameters of radiations for general practical application, or to describe their fundamental mechanisms of action, require accurate knowledge of the spatial patterns of energy deposition down to distances of the order of nanometres. Therefore, adequate descriptions are required of the nature and spatial distribution of the initial charged particles and of the interaction-by-interaction structure of the ensuing charged particle tracks. Recent development and application of Monte Carlo track structure simulations have already made it possible to commence such analyses of radiobiological data. (author). 56 refs, 7 figs

From Molecules to Living Organisms : an Interplay between Biology and Physics : Lecture Notes of the Les Houches School of Physics

CERN Document Server

Nury, Hughes; Parcy, François; Ruigrok, Rob W H; Ziegler, Christine; Cugliandolo, Leticia F; Session CII

2016-01-01

The aim of this book is to provide new ideas for studying living matter by a simultaneous understanding of behavior from molecules to the cell, to the whole organism in the light of physical concepts. Indeed, forces guide most biological phenomena. In some cases these forces can be well-described and thus used to model a particular biological phenomenon. This is exemplified here by the study of membranes, where their shapes and curvatures can be modeled using a limited number of parameters that are measured experimentally. The growth of plants is another example where the combination of physics, biology and mathematics leads to a predictive model. The laws of thermodynamics are essential, as they dictate the behavior of proteins, or more generally biological molecules, in an aqueous environment. Integrated studies from the molecule to a larger scale need a combination of cutting-edge approaches, such as the use of new X-ray sources, in-cell NMR, cryo-electron microscopy or single-molecule microscopy. Some are...

Milkweed Seed Dispersal: A Means for Integrating Biology and Physics.

Science.gov (United States)

Bisbee, Gregory D.; Kaiser, Cheryl A.

1997-01-01

Describes an activity that integrates biology and physics concepts by experimenting with the seed dispersal of common milkweed or similar wind-dispersed seeds. Student teams collect seeds and measure several parameters, review principles of trajectory motion, perform experiments, and graph data. Students examine the ideas of…

Essential concepts and underlying theories from physics, chemistry, and mathematics for "biochemistry and molecular biology" majors.

Science.gov (United States)

Wright, Ann; Provost, Joseph; Roecklein-Canfield, Jennifer A; Bell, Ellis

2013-01-01

Over the past two years, through an NSF RCN UBE grant, the ASBMB has held regional workshops for faculty members from around the country. The workshops have focused on developing lists of Core Principles or Foundational Concepts in Biochemistry and Molecular Biology, a list of foundational skills, and foundational concepts from Physics, Chemistry, and Mathematics that all Biochemistry or Molecular Biology majors must understand to complete their major coursework. The allied fields working group created a survey to validate foundational concepts from Physics, Chemistry, and Mathematics identified from participant feedback at various workshops. One-hundred twenty participants responded to the survey and 68% of the respondents answered yes to the question: "We have identified the following as the core concepts and underlying theories from Physics, Chemistry, and Mathematics that Biochemistry majors or Molecular Biology majors need to understand after they complete their major courses: 1) mechanical concepts from Physics, 2) energy and thermodynamic concepts from Physics, 3) critical concepts of structure from chemistry, 4) critical concepts of reactions from Chemistry, and 5) essential Mathematics. In your opinion, is the above list complete?" Respondents also delineated subcategories they felt should be included in these broad categories. From the results of the survey and this analysis the allied fields working group constructed a consensus list of allied fields concepts, which will help inform Biochemistry and Molecular Biology educators when considering the ASBMB recommended curriculum for Biochemistry or Molecular Biology majors and in the development of appropriate assessment tools to gauge student understanding of how these concepts relate to biochemistry and molecular biology. © 2013 by The International Union of Biochemistry and Molecular Biology.

[Chemical, physical and biological risks in law enforcement].

Science.gov (United States)

Magrini, Andrea; Grana, Mario; Vicentini, Laura

2014-01-01

Chemical, physical and biological risks among public safety and security forces. Law enforcement personnel, involved in routine tasks and in emergency situations, are exposed to numerous and several occupational hazards (chemical, physical and biological) whith likely health and security consequences. These risks are particularly high when the organization and preparation are inadequate, there is a lacking or insufficient coordination, information, education and communication and safety and personal protective equipment are inadequate or insufficient. Despite the objective difficulties, caused by the actual special needs related to the service performed or the organizational peculiarities, the risk identification and assessment is essential for worker health and safety of personnel, as provided for by Legislative Decree no. 81/2008. Chemical risks include airborne pollutants due to vehicular traffic (carbon monoxide, ultrafine particles, benzene, polycyclic aromatic hydrocarbons, aldehydes, nitrogen and sulfur oxides, lead), toxic gases generated by combustion process following fires (aromatic hydrocarbons, PAHs, dioxins and furans, biphenyls, formaldehyde, metals and cyanides), substances emitted in case of chemical accidents (solvents, pesticides, toxic gases, caustics), drugs (methylamphetamine), riot control agents and self-defence spray, lead at firing ranges, and several materials and reagents used in forensic laboratory. The physical hazards are often caused by activities that induce biomechanical overload aid the onset of musculoskeletal disorders, the use of visual display terminals and work environments that may expose to heat stress and discomfort, high and low pressure, noise, vibrations, ionizing and non-ionizing radiation. The main biological risks are blood-borne diseases (viral hepatitis, AIDS), airborne diseases (eg, tuberculosis, meningitis, SARS, anthrax), MRSA, and vector-borne diseases. Many of these risk factors are unavoidable or are not

Integration of physics and biology: synergistic undergraduate education for the 21st century.

Science.gov (United States)

Woodin, Terry; Vasaly, Helen; McBride, Duncan; White, Gary

2013-06-01

This is an exciting time to be a biologist. The advances in our field and the many opportunities to expand our horizons through interaction with other disciplines are intellectually stimulating. This is as true for people tasked with helping the field move forward through support of research and education projects that serve the nation's needs as for those carrying out that research and educating the next generation of biologists. So, it is a pleasure to contribute to this edition of CBE-Life Sciences Education. This column will cover three aspects of the interactions of physics and biology as seen from the viewpoint of four members of the Division of Undergraduate Education of the National Science Foundation. The first section places the material to follow in context. The second reviews some of the many interdisciplinary physics-biology projects we support. The third highlights mechanisms available for supporting new physics-biology undergraduate education projects based on ideas that arise, focusing on those needing and warranting outside support to come to fruition.

Biological Physics : Poincaré seminar

CERN Document Server

Bio-physique : séminaire Poincaré

2011-01-01

This new volume in the Poincaré Seminar Series, describing recent developments at the interface between physics and biology, is directed towards a broad audience of physicists, biologists, and mathematicians. Both the theoretical and experimental aspects are covered, and particular care is devoted to the pedagogical nature of the presentations. The first survey article, by Jean-Francois Joanny and Jacques Prost, describes the theoretical advances made in the study of "active gels", with applications to liquid crystals and cell motility. Jasper van der Gucht and Cécile Sykes then report on recent advances made with biomimetic model systems in the understanding of cytokinesis. The next article, by Jonathon Howard, presents several molecular models for motor proteins, which are compared with experimental results for kinesin. David Lacoste and Kirone Mallick then show theoretically that similar ratchet models of motor proteins naturally satisfy a fundamental time-reversal symmetry, the Gallavotti-Cohen fluctuat...

A generic framework for individual-based modelling and physical-biological interaction

DEFF Research Database (Denmark)

Christensen, Asbjørn; Mariani, Patrizio; Payne, Mark R.

2018-01-01

The increased availability of high-resolution ocean data globally has enabled more detailed analyses of physical-biological interactions and their consequences to the ecosystem. We present IBMlib, which is a versatile, portable and computationally effective framework for conducting Lagrangian...... scales. The open-source framework features a minimal robust interface to facilitate the coupling between individual-level biological models and oceanographic models, and we provide application examples including forward/backward simulations, habitat connectivity calculations, assessing ocean conditions...

Method to detect biological particles

International Nuclear Information System (INIS)

Giaever, I.

1976-01-01

A medical-diagnostic method to detect immunological as well as other specific reactions is described. According to the invention, first reactive particles (e.g. antibodies) are adsorbed on the surface of a solid, non-reactive substrate. The coated substrate is subjected to a solution which one assumes to contain the second biological particles (e.g. antigens) which are specific to the first and form complexes with these. A preferential radioactive labelling (e.g. with iodine 125) of the second biological particle is then directly or indirectly carried out. Clearage follows labelling in order to separate the second biological particles from the first ones. A specific splitting agent can selectively break the bond of both types of particle. The splitting agent solution is finally separated off and its content is investigated for the presence of labelling. (VJ) [de

Nuclear medicine physics

CERN Document Server

De Lima, Joao Jose

2011-01-01

Edited by a renowned international expert in the field, Nuclear Medicine Physics offers an up-to-date, state-of-the-art account of the physics behind the theoretical foundation and applications of nuclear medicine. It covers important physical aspects of the methods and instruments involved in modern nuclear medicine, along with related biological topics. The book first discusses the physics of and machines for producing radioisotopes suitable for use in conventional nuclear medicine and PET. After focusing on positron physics and the applications of positrons in medicine and biology, it descr

WE-E-17A-07: Patient-Specific Mathematical Neuro-Oncology: Biologically-Informed Radiation Therapy and Imaging Physics

Energy Technology Data Exchange (ETDEWEB)

Swanson, K; Corwin, D [Northwestern University, Chicago, IL (United States); Rockne, R

2014-06-15

Purpose: To demonstrate a method of generating patient-specific, biologically-guided radiation therapy (RT) plans and to quantify and predict response to RT in glioblastoma. We investigate the biological correlates and imaging physics driving T2-MRI based response to radiation therapy using an MRI simulator. Methods: We have integrated a patient-specific biomathematical model of glioblastoma proliferation, invasion and radiotherapy with a multiobjective evolutionary algorithm for intensity-modulated RT optimization to construct individualized, biologically-guided plans. Patient-individualized simulations of the standard-of-care and optimized plans are compared in terms of several biological metrics quantified on MRI. An extension of the PI model is used to investigate the role of angiogenesis and its correlates in glioma response to therapy with the Proliferation-Invasion-Hypoxia- Necrosis-Angiogenesis model (PIHNA). The PIHNA model is used with a brain tissue phantom to predict tumor-induced vasogenic edema, tumor and tissue density that is used in a multi-compartmental MRI signal equation for generation of simulated T2- weighted MRIs. Results: Applying a novel metric of treatment response (Days Gained) to the patient-individualized simulation results predicted that the optimized RT plans would have a significant impact on delaying tumor progression, with Days Gained increases from 21% to 105%. For the T2- MRI simulations, initial validation tests compared average simulated T2 values for white matter, tumor, and peripheral edema to values cited in the literature. Simulated results closely match the characteristic T2 value for each tissue. Conclusion: Patient-individualized simulations using the combination of a biomathematical model with an optimization algorithm for RT generated biologically-guided doses that decreased normal tissue dose and increased therapeutic ratio with the potential to improve survival outcomes for treatment of glioblastoma. Simulated T2-MRI

WE-E-17A-07: Patient-Specific Mathematical Neuro-Oncology: Biologically-Informed Radiation Therapy and Imaging Physics

International Nuclear Information System (INIS)

Swanson, K; Corwin, D; Rockne, R

2014-01-01

Purpose: To demonstrate a method of generating patient-specific, biologically-guided radiation therapy (RT) plans and to quantify and predict response to RT in glioblastoma. We investigate the biological correlates and imaging physics driving T2-MRI based response to radiation therapy using an MRI simulator. Methods: We have integrated a patient-specific biomathematical model of glioblastoma proliferation, invasion and radiotherapy with a multiobjective evolutionary algorithm for intensity-modulated RT optimization to construct individualized, biologically-guided plans. Patient-individualized simulations of the standard-of-care and optimized plans are compared in terms of several biological metrics quantified on MRI. An extension of the PI model is used to investigate the role of angiogenesis and its correlates in glioma response to therapy with the Proliferation-Invasion-Hypoxia- Necrosis-Angiogenesis model (PIHNA). The PIHNA model is used with a brain tissue phantom to predict tumor-induced vasogenic edema, tumor and tissue density that is used in a multi-compartmental MRI signal equation for generation of simulated T2- weighted MRIs. Results: Applying a novel metric of treatment response (Days Gained) to the patient-individualized simulation results predicted that the optimized RT plans would have a significant impact on delaying tumor progression, with Days Gained increases from 21% to 105%. For the T2- MRI simulations, initial validation tests compared average simulated T2 values for white matter, tumor, and peripheral edema to values cited in the literature. Simulated results closely match the characteristic T2 value for each tissue. Conclusion: Patient-individualized simulations using the combination of a biomathematical model with an optimization algorithm for RT generated biologically-guided doses that decreased normal tissue dose and increased therapeutic ratio with the potential to improve survival outcomes for treatment of glioblastoma. Simulated T2-MRI

After the Greeting: Realizing the Potential of Physical Models in Cell Biology.

Science.gov (United States)

Paluch, Ewa K

2015-12-01

Biophysics is increasingly taking center stage in cell biology as the tools for precise quantifications of cellular behaviors expand. Interdisciplinary approaches, combining quantitative physical modeling with cell biology, are of growing interest to journal editors, funding agencies, and hiring committees. However, despite an ever-increasing emphasis on the importance of interdisciplinary research, the student trained in biology may still be at a loss as to what it actually means. I discuss here some considerations on how to achieve meaningful and high-quality interdisciplinary work. Copyright © 2015 Elsevier Ltd. All rights reserved.

Does adiposity mediate the relationship between physical activity and biological risk factors in youth?

DEFF Research Database (Denmark)

Tarp, J; Bugge, A; Andersen, L B

2018-01-01

BACKGROUND/OBJECTIVES: To model the association between accumulating 60 daily minutes of moderate-to-vigorous physical activity and a composite score of biological risk factors into a direct and an indirect effect, using abdominal obesity as the mediator. SUBJECTS/METHODS: Cross-sectional data from.......11, -0.02) to the indirect effect indicating that 22% of the total effect was mediated by central adiposity. Modelling 30 and 90 min of moderate-to-vigorous physical activity per day resulted in changes in the direct but not the indirect effect. CONCLUSIONS: One hour of daily moderate...... of insulin, glucose, triacylglycerol and inverse HDL-cholesterol. Abdominal obesity was assessed by the waist-circumference:height ratio. Two-stage regression analysis, allowing for exposure-mediator interaction, was used for the effect decomposition. RESULTS: Participants achieving 60 daily minutes...

Creative design inspired by biological knowledge: Technologies and methods

Science.gov (United States)

Tan, Runhua; Liu, Wei; Cao, Guozhong; Shi, Yuan

2018-05-01

Biological knowledge is becoming an important source of inspiration for developing creative solutions to engineering design problems and even has a huge potential in formulating ideas that can help firms compete successfully in a dynamic market. To identify the technologies and methods that can facilitate the development of biologically inspired creative designs, this research briefly reviews the existing biological-knowledge-based theories and methods and examines the application of biological-knowledge-inspired designs in various fields. Afterward, this research thoroughly examines the four dimensions of key technologies that underlie the biologically inspired design (BID) process. This research then discusses the future development trends of the BID process before presenting the conclusions.

Microautoradiographic methods and their applications in biology

International Nuclear Information System (INIS)

Benes, L.

1978-01-01

A survey of microautoradiographic methods and of their application in biology is given. The current state of biological microautoradiography is shown, focusing on the efficiency of techniques and on special problems proceeding in autoradiographic investigations in biology. Four more or less independent fields of autoradiography are considered. In describing autoradiographic techniques two methodological tasks are emphasized: The further development of the labelling technique in all metabolic studies and of instrumentation and automation of autoradiograph evaluation. (author)

Multivariate analysis methods in physics

International Nuclear Information System (INIS)

Wolter, M.

2007-01-01

A review of multivariate methods based on statistical training is given. Several multivariate methods useful in high-energy physics analysis are discussed. Selected examples from current research in particle physics are discussed, both from the on-line trigger selection and from the off-line analysis. Also statistical training methods are presented and some new application are suggested [ru

Mechanobiology by the numbers: a close relationship between biology and physics.

Science.gov (United States)

Schwarz, Ulrich S

2017-12-01

Studies of mechanobiology lie at the interface of various scientific disciplines from biology to physics. Accordingly, quantification and mathematical modelling have been instrumental in fuelling the progress in this rapidly developing research field, assisting experimental work on many levels.

Novel tendencies in developing small-angle neutron scattering methods for studying the structure of biological macromolecules

International Nuclear Information System (INIS)

Serdyuk, I.

1995-01-01

In recent 20 years thermal neutron scattering has been acknowledged an important instrument for structural studies in molecular biology. The methods of neutron diffraction of high resolution, which are not discussed in this paper, have already permitted to obtain a detailed representation of the course of proteolytic reactions and have arisen a number of new problems connected with the localization of water molecules and the H-D exchange. The methods of low resolution widely used due to a relative simplicity of the experiment have been successfully applied for both solving structural problems per se and investigating the changes in the structure when macromolecules perform their biological functions. The most promising are novel experimental approaches: the triple isotopic substitution method and the method of spin dynamic polarization. These methods ensure solving structural problems at a higher resolution than the dimensions of the macromolecules studied. Installation of new experimental instruments makes neutron measurements more accessible, and development of direct methods for interpretation of experimental data using the apparatus of spherical harmonics opens new possibilities for small-angle neutron scattering making it a necessary element for interpretation of diffraction data of monocrystals of intricate biological macromolecules. The paper presents a brief account of the tendencies in theoretical development and practical use of small-angle scattering for studying biological macromolecules. Special attention is given to the studies carried out in the Laboratory of Neutron Physics on a unique pulse IBR-2 reactor. (author) 14 refs

Biology, Philosophy, and Scientific Method.

Science.gov (United States)

Hill, L.

1985-01-01

The limits of falsification are discussed and the historically based models of science described by Lakatos and Kuhn are shown to offer greater insights into the practice of science. The theory of natural selection is used to relate biology to philosophy and scientific method. (Author/JN)

Health: The No-Man's-Land Between Physics and Biology.

Science.gov (United States)

Mansfield, Peter J

2015-10-01

Health as a positive attribute is poorly understood because understanding requires concepts from physics, of which physicians and other life scientists have a very poor grasp. This paper reviews the physics that bears on biology, in particular complex quaternions and scalar fields, relates these to the morphogenetic fields proposed by biologists, and defines health as an attribute of living action within these fields. The distinction of quality, as juxtaposed with quantity, proves essential. Its basic properties are set out, but a science and mathematics of quality are awaited. The implications of this model are discussed, particularly as proper health enhancement could set a natural limit to demand for, and therefore the cost of, medical services.

Cellular response to ionizing radiations: a study of the roles of physics and biology

International Nuclear Information System (INIS)

DeWyngaert, J.K.

1982-01-01

A study of the complementary roles of physics and biology in determining the response of cellular systems to ionizing radiations has been conducted. Upon exposure to radiation, a cell responds in a binary (yes/no) manner in terms of its proliferative ability (survival). The relationship between the survival probability and absorbed dose may then be examined in terms of relevant physical and biological parameters. The approach to these studies was to vary the physics and biology independently and observe separately their influences upon the measured effect. Unique to these studies was the use of heterogeneous tumor systems. These are solid tumors found to consist of genetically related but identifiably distinct populations of cells. The two heterogeneous systems studied, a murine system consisting of four subpopulations and a human tumor system with two subpopulations, were exposed to graded doses of 14 MeV neutrons or x-rays and their effectiveness in inducing cell lethality compared. A further examination of the radiation effect involved a study at the chemical level, measuring the ability of oxygen to potentiate the damage produced by photon irradiation. To summarize, the physics, biology and the environment have all been varied, and the systematics of the responses studied. The data were analyzed within the formalisms of the dual theory of radiation action, the repair-misrepair model, and the repair saturation model of cell killing. The change in survival curve shape and the increased effectiveness in cell killing for higher Linear Energy Transfer (LET) radiations (neutrons vs. x-rays) are discussed in relation to explanations in terms of either physical or biochemical processes

Comparison of Chemical and Physical-chemical Wastewater Discoloring Methods

Directory of Open Access Journals (Sweden)

Durašević, V.

2007-11-01

Full Text Available Today's chemical and physical-chemical wastewater discoloration methods do not completely meet demands regarding degree of discoloration. In this paper discoloration was performed using Fenton (FeSO4 . 7 H2O + H2O2 + H2SO4 and Fenton-like (FeCl3 . 6 H2O + H2O2 + HCOOH chemical methods and physical-chemical method of coagulation/flocculation (using poly-electrolyte (POEL combining anion active coagulant (modified poly-acrylamides and cationic flocculant (product of nitrogen compounds in combination with adsorption on activated carbon. Suitability of aforementioned methods was investigated on reactive and acid dyes, regarding their most common use in the textile industry. Also, investigations on dyes of different chromogen (anthraquinone, phthalocyanine, azo and xanthene were carried out in order to determine the importance of molecular spatial structure. Oxidative effect of Fenton and Fenton-like reagents resulted in decomposition of colored chromogen and high degree of discoloration. However, the problem is the inability of adding POEL in stechiometrical ratio (also present in physical-chemical methods, when the phenomenon of overdosing coagulants occurs in order to obtain a higher degree of discoloration, creating a potential danger of burdening water with POEL. Input and output water quality was controlled through spectrophotometric measurements and standard biological parameters. In addition, part of the investigations concerned industrial wastewaters obtained from dyeing cotton materials using reactive dye (C. I. Reactive Blue 19, a process that demands the use of vast amounts of electrolytes. Also, investigations of industrial wastewaters was labeled as a crucial step carried out in order to avoid serious misassumptions and false conclusions, which may arise if dyeing processes are only simulated in the laboratory.

Radiation physics, biophysics, and radiation biology

International Nuclear Information System (INIS)

Hall, E.J.; Zaider, M.

1991-05-01

Research at the Radiological Research Laboratory is a blend of physics, chemistry, and biology, involving research at the basic level with the admixture of a small proportion of pragmatic or applied research in support of radiation protection and/or radiotherapy. Current research topics include: oncogenic transformation assays, mutation studies involving interactions between radiation and environmental contaminants, isolation, characterization and sequencing of a human repair gene, characterization of a dominant transforming gene found in C3H 10T1/2 cells, characterize ab initio the interaction of DNA and radiation, refine estimates of the radiation quality factor Q, a new mechanistic model of oncogenesis showing the role of long-term low dose medium LET radiation, and time dependent modeling of radiation induced chromosome damage and subsequent repair or misrepair

Biological Movement and Laws of Physics.

Science.gov (United States)

Latash, Mark L

2017-07-01

Living systems may be defined as systems able to organize new, biology-specific, laws of physics and modify their parameters for specific tasks. Examples include the force-length muscle dependence mediated by the stretch reflex, and the control of movements with modification of the spatial referent coordinates for salient performance variables. Low-dimensional sets of referent coordinates at a task level are transformed to higher-dimensional sets at lower hierarchical levels in a way that ensures stability of performance. Stability of actions can be controlled independently of the actions (e.g., anticipatory synergy adjustments). Unintentional actions reflect relaxation processes leading to drifts of corresponding referent coordinates in the absence of changes in external load. Implications of this general framework for movement disorders, motor development, motor skill acquisition, and even philosophy are discussed.

Simple Calculation Programs for Biology Immunological Methods

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Simple Calculation Programs for Biology Immunological Methods. Computation of Ab/Ag Concentration from EISA data. Graphical Method; Raghava et al., 1992, J. Immuno. Methods 153: 263. Determination of affinity of Monoclonal Antibody. Using non-competitive ...

Towards multidimensional radiotherapy (MD-CRT): biological imaging and biological conformality

International Nuclear Information System (INIS)

Ling, C. Clifton; Humm, John; Larson, Steven; Amols, Howard; Fuks, Zvi; Leibel, Steven; Koutcher, Jason A.

2000-01-01

Purpose: The goals of this study were to survey and summarize the advances in imaging that have potential applications in radiation oncology, and to explore the concept of integrating physical and biological conformality in multidimensional conformal radiotherapy (MD-CRT). Methods and Materials: The advances in three-dimensional conformal radiotherapy (3D-CRT) have greatly improved the physical conformality of treatment planning and delivery. The development of intensity-modulated radiotherapy (IMRT) has provided the 'dose painting' or 'dose sculpting' ability to further customize the delivered dose distribution. The improved capabilities of nuclear magnetic resonance imaging and spectroscopy, and of positron emission tomography, are beginning to provide physiological and functional information about the tumor and its surroundings. In addition, molecular imaging promises to reveal tumor biology at the genotype and phenotype level. These developments converge to provide significant opportunities for enhancing the success of radiotherapy. Results: The ability of IMRT to deliver nonuniform dose patterns by design brings to fore the question of how to 'dose paint' and 'dose sculpt', leading to the suggestion that 'biological' images may be of assistance. In contrast to the conventional radiological images that primarily provide anatomical information, biological images reveal metabolic, functional, physiological, genotypic, and phenotypic data. Important for radiotherapy, the new and noninvasive imaging methods may yield three-dimensional radiobiological information. Studies are urgently needed to identify genotypes and phenotypes that affect radiosensitivity, and to devise methods to image them noninvasively. Incremental to the concept of gross, clinical, and planning target volumes (GTV, CTV, and PTV), we propose the concept of 'biological target volume' (BTV) and hypothesize that BTV can be derived from biological images and that their use may incrementally improve

Devices for overcoming biological barriers: the use of physical forces to disrupt the barriers.

Science.gov (United States)

Mitragotri, Samir

2013-01-01

Overcoming biological barriers including skin, mucosal membranes, blood brain barrier as well as cell and nuclear membrane constitutes a key hurdle in the field of drug delivery. While these barriers serve the natural protective function in the body, they limit delivery of drugs into the body. A variety of methods have been developed to overcome these barriers including formulations, targeting peptides and device-based technologies. This review focuses on the use of physical methods including acoustic devices, electric devices, high-pressure devices, microneedles and optical devices for disrupting various barriers in the body including skin and other membranes. A summary of the working principles of these devices and their ability to enhance drug delivery is presented. Copyright © 2012. Published by Elsevier B.V.

Biological methods used to assess surface water quality

Directory of Open Access Journals (Sweden)

Szczerbiñska Natalia

2015-12-01

Full Text Available In accordance with the guidelines of the Water Framework Directive 2000/60 (WFD, both ecological and chemical statuses determine the assessment of surface waters. The profile of ecological status is based on the analysis of various biological components, and physicochemical and hydromorphological indicators complement this assessment. The aim of this article is to present the biological methods used in the assessment of water status with a special focus on bioassay, as well as to provide a review of methods of monitoring water status. Biological test methods include both biomonitoring and bioanalytics. Water biomonitoring is used to assess and forecast the status of water. These studies aim to collect data on water pollution and forecast its impact. Biomonitoring uses organisms which are characterized by particular vulnerability to contaminants. Bioindicator organisms are algae, fungi, bacteria, larval invertebrates, cyanobacteria, macroinvertebrates, and fish. Bioanalytics is based on the receptors of contaminants that can be biologically active substances. In bioanalytics, biosensors such as viruses, bacteria, antibodies, enzymes, and biotests are used to assess degrees of pollution.

4D-Var data assimilation system for a coupled physical-biological ...

Indian Academy of Sciences (India)

A 3-compartment model of phytoplankton growth dynamics has been coupled with a primitive-equation circulation model to better understand and quantify physical and biological processes in the Adriatic Sea. This paper presents the development and application of a data assimilation procedure based on optimal.

S.E.A. Lab. Science Experiments and Activities. Marine Science for High School Students in Chemistry, Biology and Physics.

Science.gov (United States)

Hart, Kathy, Ed.

A series of science experiments and activities designed for secondary school students taking biology, chemistry, physics, physical science or marine science courses are outlined. Each of the three major sections--chemistry, biology, and physics--addresses concepts that are generally covered in those courses but incorporates aspects of marine…

Radiation physics, biophysics, and radiation biology. Progress report, December 1, 1993--November 30, 1994

Energy Technology Data Exchange (ETDEWEB)

Hall, E.J.; Zaider, M.

1994-05-01

Research at the Center for Radiological Research is a blend of physics, chemistry and biology and epitomizes the multidisciplinary approach towards understanding the mechanisms involved in the health problems resulting from human exposure to ionizing radiations. To an increasing extent, the focus of attention is on biochemistry and the application of the techniques of molecular biology to the problems of radiation biology. Research highlights from the past year are briefly described.

Radiation physics, biophysics, and radiation biology. Progress report, December 1, 1993--November 30, 1994

International Nuclear Information System (INIS)

Hall, E.J.; Zaider, M.

1994-05-01

Research at the Center for Radiological Research is a blend of physics, chemistry and biology and epitomizes the multidisciplinary approach towards understanding the mechanisms involved in the health problems resulting from human exposure to ionizing radiations. To an increasing extent, the focus of attention is on biochemistry and the application of the techniques of molecular biology to the problems of radiation biology. Research highlights from the past year are briefly described

Quantifying bioalbedo: a new physically based model and discussion of empirical methods for characterising biological influence on ice and snow albedo

Science.gov (United States)

Cook, Joseph M.; Hodson, Andrew J.; Gardner, Alex S.; Flanner, Mark; Tedstone, Andrew J.; Williamson, Christopher; Irvine-Fynn, Tristram D. L.; Nilsson, Johan; Bryant, Robert; Tranter, Martyn

2017-11-01

The darkening effects of biological impurities on ice and snow have been recognised as a control on the surface energy balance of terrestrial snow, sea ice, glaciers and ice sheets. With a heightened interest in understanding the impacts of a changing climate on snow and ice processes, quantifying the impact of biological impurities on ice and snow albedo (bioalbedo) and its evolution through time is a rapidly growing field of research. However, rigorous quantification of bioalbedo has remained elusive because of difficulties in isolating the biological contribution to ice albedo from that of inorganic impurities and the variable optical properties of the ice itself. For this reason, isolation of the biological signature in reflectance data obtained from aerial/orbital platforms has not been achieved, even when ground-based biological measurements have been available. This paper provides the cell-specific optical properties that are required to model the spectral signatures and broadband darkening of ice. Applying radiative transfer theory, these properties provide the physical basis needed to link biological and glaciological ground measurements with remotely sensed reflectance data. Using these new capabilities we confirm that biological impurities can influence ice albedo, then we identify 10 challenges to the measurement of bioalbedo in the field with the aim of improving future experimental designs to better quantify bioalbedo feedbacks. These challenges are (1) ambiguity in terminology, (2) characterising snow or ice optical properties, (3) characterising solar irradiance, (4) determining optical properties of cells, (5) measuring biomass, (6) characterising vertical distribution of cells, (7) characterising abiotic impurities, (8) surface anisotropy, (9) measuring indirect albedo feedbacks, and (10) measurement and instrument configurations. This paper aims to provide a broad audience of glaciologists and biologists with an overview of radiative transfer and

Quantifying bioalbedo: a new physically based model and discussion of empirical methods for characterising biological influence on ice and snow albedo

Directory of Open Access Journals (Sweden)

J. M. Cook

2017-11-01

Full Text Available The darkening effects of biological impurities on ice and snow have been recognised as a control on the surface energy balance of terrestrial snow, sea ice, glaciers and ice sheets. With a heightened interest in understanding the impacts of a changing climate on snow and ice processes, quantifying the impact of biological impurities on ice and snow albedo (bioalbedo and its evolution through time is a rapidly growing field of research. However, rigorous quantification of bioalbedo has remained elusive because of difficulties in isolating the biological contribution to ice albedo from that of inorganic impurities and the variable optical properties of the ice itself. For this reason, isolation of the biological signature in reflectance data obtained from aerial/orbital platforms has not been achieved, even when ground-based biological measurements have been available. This paper provides the cell-specific optical properties that are required to model the spectral signatures and broadband darkening of ice. Applying radiative transfer theory, these properties provide the physical basis needed to link biological and glaciological ground measurements with remotely sensed reflectance data. Using these new capabilities we confirm that biological impurities can influence ice albedo, then we identify 10 challenges to the measurement of bioalbedo in the field with the aim of improving future experimental designs to better quantify bioalbedo feedbacks. These challenges are (1 ambiguity in terminology, (2 characterising snow or ice optical properties, (3 characterising solar irradiance, (4 determining optical properties of cells, (5 measuring biomass, (6 characterising vertical distribution of cells, (7 characterising abiotic impurities, (8 surface anisotropy, (9 measuring indirect albedo feedbacks, and (10 measurement and instrument configurations. This paper aims to provide a broad audience of glaciologists and biologists with an overview of

Biological and Physical Space Research Laboratory 2002 Science Review

Science.gov (United States)

Curreri, P. A. (Editor); Robinson, M. B. (Editor); Murphy, K. L. (Editor)

2003-01-01

With the International Space Station Program approaching core complete, our NASA Headquarters sponsor, the new Code U Enterprise, Biological and Physical Research, is shifting its research emphasis from purely fundamental microgravity and biological sciences to strategic research aimed at enabling human missions beyond Earth orbit. Although we anticipate supporting microgravity research on the ISS for some time to come, our laboratory has been vigorously engaged in developing these new strategic research areas.This Technical Memorandum documents the internal science research at our laboratory as presented in a review to Dr. Ann Whitaker, MSFC Science Director, in July 2002. These presentations have been revised and updated as appropriate for this report. It provides a snapshot of the internal science capability of our laboratory as an aid to other NASA organizations and the external scientific community.

Introduction on microbiological and biological methods and their possible combination with other analytical techniques for the detection of irradiated food

International Nuclear Information System (INIS)

Leonardi, M.

1991-01-01

Food irradiation is a physical method of processing and preserving food. One of the main purposes of the application of this technology to food is to obtain specific biological effects on the treated foodstuff. Typical examples of these treatment effects are listed in the article. A whole range of techniques is at disposal of the analyst to assure the Quality Control (QC) of various foodstuffs. They are based on microbiological, organoleptical, chemical, biochemical, immunological and/or physical methods. In the case of irradiation preserved food the opinion of the writer is that very often only a combination of analytical methods can solve the problem of detection of irradiated foodstuffs and in particular in most cases this combination could be formed by a biological or microbiological method + a chemical or physical one. The meaning of these combination of techniques is manifold. Combining the advantages of a rapid screening method with those of a more refined, reliable, even if more time consuming one; offering the possibility to carry out the analysis for the control of irradiated foodstuffs to different kinds of food control laboratories, often equipped in a different way, are some of the most evident advantages. These methods are briefly explained. At present, none method seems promising for the quantitative determination of the irradiation dose. Moreover, some of the proposed methods can only give a good presumption of the irradiation treatment applied to particular foodstuffs. (18 refs)

Nuclear physics methods in materials research

International Nuclear Information System (INIS)

Bethge, K.; Baumann, H.; Jex, H.; Rauch, F.

1980-01-01

Proceedings of the seventh divisional conference of the Nuclear Physics Division held at Darmstadt, Germany, from 23rd through 26th of September, 1980. The scope of this conference was defined as follows: i) to inform solid state physicists and materials scientists about the application of nuclear physics methods; ii) to show to nuclear physicists open questions and problems in solid state physics and materials science to which their methods can be applied. According to the intentions of the conference, the various nuclear physics methods utilized in solid state physics and materials science and especially new developments were reviewed by invited speakers. Detailed aspects of the methods and typical examples extending over a wide range of applications were presented as contributions in poster sessions. The Proceedings contain all the invited papers and about 90% of the contributed papers. (orig./RW)

Statistical physics and computational methods for evolutionary game theory

CERN Document Server

Javarone, Marco Alberto

2018-01-01

This book presents an introduction to Evolutionary Game Theory (EGT) which is an emerging field in the area of complex systems attracting the attention of researchers from disparate scientific communities. EGT allows one to represent and study several complex phenomena, such as the emergence of cooperation in social systems, the role of conformity in shaping the equilibrium of a population, and the dynamics in biological and ecological systems. Since EGT models belong to the area of complex systems, statistical physics constitutes a fundamental ingredient for investigating their behavior. At the same time, the complexity of some EGT models, such as those realized by means of agent-based methods, often require the implementation of numerical simulations. Therefore, beyond providing an introduction to EGT, this book gives a brief overview of the main statistical physics tools (such as phase transitions and the Ising model) and computational strategies for simulating evolutionary games (such as Monte Carlo algor...

Molecular physics. Theoretical principles and experimental methods

International Nuclear Information System (INIS)

Demtroeder, W.

2005-01-01

This advanced textbook comprehensively explains important principles of diatomic and polyatomic molecules and their spectra in two separate, distinct parts. The first part concentrates on the theoretical aspects of molecular physics, whereas the second part of the book covers experimental techniques, i.e. laser, Fourier, NMR, and ESR spectroscopies, used in the fields of physics, chemistry, biolog, and material science. Appropriate for undergraduate and graduate students in physics and chemistry with a knowledge of atomic physics and familiar with the basics of quantum mechanics. From the contents: - Electronic States of Molecules, - Rotation, Oscillation and Potential Curves of Diatomic Molecules, - The Spectra of Diatomic Molecules, - Molecule Symmetries and Group Theory, - Rotation and Oscillations of Polyatomic Molecules, - Electronic States of Polyatomic Molecules, - The Spectra of Polyatomic Molecules, - Collapse of the Born-Oppenheimer-Approximation, Disturbances in Molecular Spectra, - Molecules in Disturbing Fields, - Van-der-Waals-Molecules and Cluster, - Experimental Techniques in Molecular Physics. (orig.)

Implementation of statistical analysis methods for medical physics data; Implementacao de metodos de analise estatistica para dados de fisica medica

Energy Technology Data Exchange (ETDEWEB)

Teixeira, Marilia S.; Pinto, Nivia G.P.; Barroso, Regina C.; Oliveira, Luis F., E-mail: mariliasilvat@gmail.co, E-mail: lfolive@oi.com.b, E-mail: cely_barroso@hotmail.co, E-mail: nitatag@gmail.co [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Inst. de Fisica

2009-07-01

The objective of biomedical research with different radiation natures is to contribute for the understanding of the basic physics and biochemistry of the biological systems, the disease diagnostic and the development of the therapeutic techniques. The main benefits are: the cure of tumors through the therapy, the anticipated detection of diseases through the diagnostic, the using as prophylactic mean for blood transfusion, etc. Therefore, for the better understanding of the biological interactions occurring after exposure to radiation, it is necessary for the optimization of therapeutic procedures and strategies for reduction of radioinduced effects. The group pf applied physics of the Physics Institute of UERJ have been working in the characterization of biological samples (human tissues, teeth, saliva, soil, plants, sediments, air, water, organic matrixes, ceramics, fossil material, among others) using X-rays diffraction and X-ray fluorescence. The application of these techniques for measurement, analysis and interpretation of the biological tissues characteristics are experimenting considerable interest in the Medical and Environmental Physics. All quantitative data analysis must be initiated with descriptive statistic calculation (means and standard deviations) in order to obtain a previous notion on what the analysis will reveal. It is well known que o high values of standard deviation found in experimental measurements of biologicals samples can be attributed to biological factors, due to the specific characteristics of each individual (age, gender, environment, alimentary habits, etc). This work has the main objective the development of a program for the use of specific statistic methods for the optimization of experimental data an analysis. The specialized programs for this analysis are proprietary, another objective of this work is the implementation of a code which is free and can be shared by the other research groups. As the program developed since the

4D-Var data assimilation system for a coupled physical biological ...

Indian Academy of Sciences (India)

A 3-compartment model of phytoplankton growth dynamics has been coupled with a primitive-equation circulation model to better understand and quantify physical and biological processes in the Adriatic Sea. This paper presents the development and application of a data assimilation procedure based on optimal control ...

Physics of non-Newtonian fluids and interdisciplinary relations (biology and criminology)

Science.gov (United States)

Holubova, R.

2018-03-01

The aim of the paper is the presentation of an interdisciplinary topic that allows applying content knowledge in physics, mathematics and biology in real life environment. Students use to play games and view crime scenes but in common they have little knowledge about the science used during crime scene investigation. In this paper the science background of blood spatter analysis is presented—the physics of non-Newtonian fluids, the biology of blood and mathematics—the measurement and calculation of the angle of inpact, the relationship between height and spatter diameter. This topic was choosen according to the analysis of interviews with secondary and high school learners realized at four schools in Moravia, Czech Republic. The topic can be taught at secondary schools so as at a higher level at high schools. Hands-on activities are included. The teaching strategy supports group work. The appropriateness and reasonableness of the topic was checked in the real teaching process and the activities have had a positive feedback.

Modelling the Influence of Shielding on Physical and Biological Organ Doses

CERN Document Server

Ballarini, Francesca; Ferrari, Alfredo; Ottolenghi, Andrea; Pelliccioni, Maurizio; Scannicchio, Domenico

2002-01-01

Distributions of "physical" and "biological" dose in different organs were calculated by coupling the FLUKA MC transport code with a geometrical human phantom inserted into a shielding box of variable shape, thickness and material. While the expression "physical dose" refers to the amount of deposited energy per unit mass (in Gy), "biological dose" was modelled with "Complex Lesions" (CL), clustered DNA strand breaks calculated in a previous work based on "event-by-event" track-structure simulations. The yields of complex lesions per cell and per unit dose were calculated for different radiation types and energies, and integrated into a version of FLUKA modified for this purpose, allowing us to estimate the effects of mixed fields. As an initial test simulation, the phantom was inserted into an aluminium parallelepiped and was isotropically irradiated with 500 MeV protons. Dose distributions were calculated for different values of the shielding thickness. The results were found to be organ-dependent. In most ...

Research Data in Core Journals in Biology, Chemistry, Mathematics, and Physics.

Directory of Open Access Journals (Sweden)

Ryan P Womack

Full Text Available This study takes a stratified random sample of articles published in 2014 from the top 10 journals in the disciplines of biology, chemistry, mathematics, and physics, as ranked by impact factor. Sampled articles were examined for their reporting of original data or reuse of prior data, and were coded for whether the data was publicly shared or otherwise made available to readers. Other characteristics such as the sharing of software code used for analysis and use of data citation and DOIs for data were examined. The study finds that data sharing practices are still relatively rare in these disciplines' top journals, but that the disciplines have markedly different practices. Biology top journals share original data at the highest rate, and physics top journals share at the lowest rate. Overall, the study finds that within the top journals, only 13% of articles with original data published in 2014 make the data available to others.

Supporting students in building interdisciplinary connections across physics and biology

Science.gov (United States)

Turpen, Chandra

2014-03-01

Our research team has been engaged in the iterative redesign of an Introductory Physics course for Life Science (IPLS) majors to explicitly bridge biology and physics in ways that are authentic to the disciplines. Our interdisciplinary course provides students opportunities to examine how modeling decisions (e.g. knowing when and how to use different concepts, identifying implicit assumptions, making and justifying assumptions) may differ depending on canonical disciplinary aims and interests. Our focus on developing students' interdisciplinary reasoning skills requires 1) shifting course topics to focus on core ideas that span the disciplines, 2) shifting epistemological expectations, and 3) foregrounding typically tacit disciplinary assumptions. In working to build an authentic interdisciplinary course that bridges physics and biology, we pay careful attention to supporting students in constructing these bridges. This course has been shown to have important impacts: a) students seek meaningful connections between the disciplines, b) students perceive relevance and utility of ideas from different disciplines, and c) students reconcile challenging disciplinary ideas. Although our focus has been on building interdisciplinary coherence, we have succeeded in maintaining strong student learning gains on fundamental physics concepts and allowed students to deepen their understanding of challenging concepts in thermodynamics. This presentation will describe the shifts in course content and the modern pedagogical approaches that have been integrated into the course, and provide an overview of key research results from this project. These results may aid physicists in reconsidering how they can meaningfully reach life-science students. This work is supported by NSF-TUES DUE 11-22818, the HHMI NEXUS grant, and a NSF Graduate Research Fellowship (DGE 0750616).

Monte Carlo Methods in Physics

International Nuclear Information System (INIS)

Santoso, B.

1997-01-01

Method of Monte Carlo integration is reviewed briefly and some of its applications in physics are explained. A numerical experiment on random generators used in the monte Carlo techniques is carried out to show the behavior of the randomness of various methods in generating them. To account for the weight function involved in the Monte Carlo, the metropolis method is used. From the results of the experiment, one can see that there is no regular patterns of the numbers generated, showing that the program generators are reasonably good, while the experimental results, shows a statistical distribution obeying statistical distribution law. Further some applications of the Monte Carlo methods in physics are given. The choice of physical problems are such that the models have available solutions either in exact or approximate values, in which comparisons can be mode, with the calculations using the Monte Carlo method. Comparison show that for the models to be considered, good agreement have been obtained

Shoreline clean-up methods : biological treatments

Energy Technology Data Exchange (ETDEWEB)

Massoura, S.T. [Oil Spill Response Limited, Southampton (United Kingdom)

2009-07-01

The cleanup of oil spills in shoreline environments is a challenging issue worldwide. Oil spills receive public and media attention, particularly in the event of a coastal impact. It is important to evaluate the efficiency and effectiveness of cleanup methods when defining the level of effort and consequences that are appropriate to remove or treat different types of oil on different shoreline substrates. Of the many studies that have compared different mechanical, chemical and biological treatments for their effectiveness on various types of oil, biological techniques have received the most attention. For that reason, this paper evaluated the effectiveness and effects of shoreline cleanup methods using biological techniques. It summarized data from field experiments and oil spill incidents, including the Exxon Valdez, Sea Empress, Prestige, Grand Eagle, Nakhodka, Guanabara Bay and various Gulf war oil spills. Five major shoreline types were examined, notably rocky intertidal, cobble/pebble/gravel, sand/mud, saltmarsh, and mangrove/sea-grass. The biological techniques that were addressed were nutrient enrichment, hydrocarbon-utilizing bacteria, vegetable oil biosolvents, plants, surf washing, oil-particle interactions and natural attenuation. The study considered the oil type, volume and fate of stranded oil, location of coastal materials, extent of pollution and the impact of biological techniques. The main factors that affect biodegradation of hydrocarbons are the volume, chemical composition and weathering state of the petroleum product as well as the temperature, oxygen availability of nutrients, water salinity, pH level, water content, and microorganisms in the shoreline environment. The interaction of these factors also affect the biodegradation of oil. It was concluded that understanding the fate of stranded oil can help in the development of techniques that improve the weathering and degradation of oil on complex shoreline substrates. 39 refs.

Entropy as a method to investigate complex biological systems. An alternative view on the biological transition from healthy aging to frailty

Directory of Open Access Journals (Sweden)

Roberto Siciliano

2017-07-01

Full Text Available Everyone is subject to a process of progressive deterioration of control mechanisms, which supervise the complex network of human physiological functions, reducing the individual ability to adapt to emerging situations of stress or change. In the light of results obtained during the last years, it appears that some of the tools of nonlinear dynamics, first developed for the physical sciences are well suited for studies of biological systems. We believe that, considering the level of order or complexity of the anatomical apparatus by measuring a physical quantity, which is the entropy, we can evaluate the health status or vice versa fragility of a biological system. In particular, a reduction in the entropy value, indicates modification of the structural order with a progressive reduction of functional reserve of the individual, which is associated with a failure to adapt to stress conditions, difficult to be analyzed and documented with a unique traditional biochemical or biomolecular vision. Therefore, in this paper, we present a method that, conceptually combines complexity, disease and aging, alloys Poisson statistics, predictive of the personal level of health, to the entropy value indicating the status of bio-dynamic and functional body, seen as a complex and open thermodynamic system.

Fundamentals of bioinformatics and computational biology methods and exercises in matlab

CERN Document Server

Singh, Gautam B

2015-01-01

This book offers comprehensive coverage of all the core topics of bioinformatics, and includes practical examples completed using the MATLAB bioinformatics toolbox™. It is primarily intended as a textbook for engineering and computer science students attending advanced undergraduate and graduate courses in bioinformatics and computational biology. The book develops bioinformatics concepts from the ground up, starting with an introductory chapter on molecular biology and genetics. This chapter will enable physical science students to fully understand and appreciate the ultimate goals of applying the principles of information technology to challenges in biological data management, sequence analysis, and systems biology. The first part of the book also includes a survey of existing biological databases, tools that have become essential in today’s biotechnology research. The second part of the book covers methodologies for retrieving biological information, including fundamental algorithms for sequence compar...

Leveraging a Relationship with Biology to Expand a Relationship with Physics

Science.gov (United States)

Sawtelle, Vashti; Turpen, Chandra

2016-01-01

This work examines how experiences in one disciplinary domain (biology) can impact the relationship a student builds with another domain (physics). We present a model for disciplinary relationships using the constructs of identity, affect, and epistemology. With these constructs we examine an ethnographic case study of a student who experienced a…

Simple Calculation Programs for Biology Methods in Molecular ...

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Simple Calculation Programs for Biology Methods in Molecular Biology. GMAP: A program for mapping potential restriction sites. RE sites in ambiguous and non-ambiguous DNA sequence; Minimum number of silent mutations required for introducing a RE sites; Set ...

Radiation physics, biophysics, and radiation biology: Progress report, December 1, 1987-November 30, 1988

International Nuclear Information System (INIS)

Hall, E.J.; Zaider, M.; Delegianis, M.J.

1988-07-01

Research at the Radiological Research Laboratory is a blend of physics, chemistry, and biology, involving research at the basic level with the admixture of a small proportion of pragmatic or applied research in support of radiation protection and/or radiation therapy. At the current level of funding, approximately one quarter of the research of the Laboratory could be regarded as in support of radiotherapy, with the remainder addressing more basic issues. The new initiatives have been in two directions. First, there has been an increased emphasis on research in radiation chemistry, inasmuch as this subject which involves the study of free radicals and fast radiation chemistry processes starts to bridge the gap between physics and biology, between the initial deposition of radiant energy and its final expression in terms of biological consequences. Second, the emphasis in the biological research has moved towards studies at the molecular level, with the appointment of new members of staff with expertise in this area. Individual chapters were processed separately for the data base

Statistical methods for physical science

CERN Document Server

Stanford, John L

1994-01-01

This volume of Methods of Experimental Physics provides an extensive introduction to probability and statistics in many areas of the physical sciences, with an emphasis on the emerging area of spatial statistics. The scope of topics covered is wide-ranging-the text discusses a variety of the most commonly used classical methods and addresses newer methods that are applicable or potentially important. The chapter authors motivate readers with their insightful discussions, augmenting their material withKey Features* Examines basic probability, including coverage of standard distributions, time s

The definitions of information and meaning two possible boundaries between physics and biology.

Science.gov (United States)

Barbieri, Marcello

2004-01-01

The standard approach to the definition of the physical quantities has not produced satisfactory results with the concepts of information and meaning. In the case of information we have at least two unrelated definitions, while in the case of meaning we have no definition at all. Here it is shown that both information and meaning can be defined by operative procedures, but it is also pointed out that we need to recognize them as a new type of natural entities. They are not quantities (neither fundamental nor derived) because they cannot be measured, and they are not qualities because are not subjective features. Here it is proposed to call them nominable entities, i.e., entities which can be specified only by naming their components in their natural order. If the genetic code is not a linguistic metaphor but a reality, we must conclude that information and meaning are real natural entities, and now we must also conclude that they are not equivalent to the quantities and qualities of our present theoretical framework. This gives us two options. One is to extend the definition of physics and say that the list of its fundamental entities must include information and meaning. The other is to say that physics is the science of quantities only, and in this case information and meaning become the exclusive province of biology. The boundary between physics and biology, in short, is a matter of convention, but the existence of information and meaning is not. We can decide to study them in the framework of an extended physics or in a purely biological framework, but we cannot avoid studying them for what they are, i.e., as fundamental components of the fabric of Nature.

Simple Calculation Programs for Biology Other Methods

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Simple Calculation Programs for Biology Other Methods. Hemolytic potency of drugs. Raghava et al., (1994) Biotechniques 17: 1148. FPMAP: methods for classification and identification of microorganisms 16SrRNA. graphical display of restriction and fragment map of ...

The Use of Textbooks for Advanced-Level GCE Courses in Physics, Chemistry and Biology by Sixth-Form Students.

Science.gov (United States)

Newton, D. P.

1984-01-01

A survey of sixth-form students to determine the level of A-level textbook use in physics, chemistry, and biology in English schools found that texts are used primarily after the lesson, at the student's discretion, and with great variations between students. Biology texts were used most, and physics texts used least. (MBR)

Microbeam radiation therapy. Physical and biological aspects of a new cancer therapy and development of a treatment planning system

Energy Technology Data Exchange (ETDEWEB)

Bartzsch, Stefan

2014-11-05

Microbeam Radiation Therapy (MRT) is a novel treatment strategy against cancer. Highly brilliant synchrotron radiation is collimated to parallel, a few micrometre wide, planar beams and used to irradiate malignant tissues with high doses. The applied peak doses are considerably higher than in conventional radiotherapy, but valley doses between the beams remain underneath the established tissue tolerance. Previous research has shown that these beam geometries spare normal tissue, while being effective in tumour ablation. In this work physical and biological aspects of the therapy were investigated. A therapy planning system was developed for the first clinical treatments at the European Synchrotron Radiation Facility in Grenoble (France) and a dosimetry method based on radiochromic films was created to validate planned doses with measurements on a micrometre scale. Finally, experiments were carried out on a cellular level in order to correlate the physically planned doses with the biological damage caused in the tissue. The differences between Monte Carlo dose and dosimetry are less than 10% in the valley and 5% in the peak regions. Developed alternative faster dose calculation methods deviate from the computational intensive MC simulations by less than 15% and are able to determine the dose within a few minutes. The experiments in cell biology revealed an significant influence of intercellular signalling on the survival of cells close to radiation boundaries. These observations may not only be important for MRT but also for conventional radiotherapy.

Physical Chemistry for the Chemical and Biological Sciences (by Raymond Chang)

Science.gov (United States)

Pounds, Andrew

2001-05-01

This book does offer an alternative approach to physical chemistry that is particularly well suited for those who want to pursue a course of study more focused on the biological sciences. It could also be an excellent choice for schools that mainly serve preprofessional programs or for schools that have split physical chemistry tracks to independently serve the B.S. and B.A. degrees. Since the book focuses on single-variable mathematics, schools that require only one year of calculus for their chemistry degree could also think about adopting it. However, in general, the use of the text as a drop-in replacement for physical chemistry for the B.S. degree is questionable owing to its lack of focus on quantum mechanics and its implications for spectroscopy.

Integrating soil physical and biological properties in contrasting tillage systems in organic and conventional farming

NARCIS (Netherlands)

Crittenden, S.J.; Goede, de R.G.M.

2016-01-01

Though soil physical and soil biological properties are intrinsically linked in the soil environment they are often studied separately. This work adds value to analyses of soil biophysical quality of tillage systems under organic and conventional farming systems by correlating physical and

Physics of Non-Newtonian Fluids and Interdisciplinary Relations (Biology and Criminology)

Science.gov (United States)

Holubova, R.

2018-01-01

The aim of the paper is the presentation of an interdisciplinary topic that allows applying content knowledge in physics, mathematics and biology in real life environment. Students use to play games and view crime scenes but in common they have little knowledge about the science used during crime scene investigation. In this paper the science…

An novel frequent probability pattern mining algorithm based on circuit simulation method in uncertain biological networks

Science.gov (United States)

2014-01-01

Background Motif mining has always been a hot research topic in bioinformatics. Most of current research on biological networks focuses on exact motif mining. However, due to the inevitable experimental error and noisy data, biological network data represented as the probability model could better reflect the authenticity and biological significance, therefore, it is more biological meaningful to discover probability motif in uncertain biological networks. One of the key steps in probability motif mining is frequent pattern discovery which is usually based on the possible world model having a relatively high computational complexity. Methods In this paper, we present a novel method for detecting frequent probability patterns based on circuit simulation in the uncertain biological networks. First, the partition based efficient search is applied to the non-tree like subgraph mining where the probability of occurrence in random networks is small. Then, an algorithm of probability isomorphic based on circuit simulation is proposed. The probability isomorphic combines the analysis of circuit topology structure with related physical properties of voltage in order to evaluate the probability isomorphism between probability subgraphs. The circuit simulation based probability isomorphic can avoid using traditional possible world model. Finally, based on the algorithm of probability subgraph isomorphism, two-step hierarchical clustering method is used to cluster subgraphs, and discover frequent probability patterns from the clusters. Results The experiment results on data sets of the Protein-Protein Interaction (PPI) networks and the transcriptional regulatory networks of E. coli and S. cerevisiae show that the proposed method can efficiently discover the frequent probability subgraphs. The discovered subgraphs in our study contain all probability motifs reported in the experiments published in other related papers. Conclusions The algorithm of probability graph isomorphism

Ground truth methods for optical cross-section modeling of biological aerosols

Science.gov (United States)

Kalter, J.; Thrush, E.; Santarpia, J.; Chaudhry, Z.; Gilberry, J.; Brown, D. M.; Brown, A.; Carter, C. C.

2011-05-01

Light detection and ranging (LIDAR) systems have demonstrated some capability to meet the needs of a fastresponse standoff biological detection method for simulants in open air conditions. These systems are designed to exploit various cloud signatures, such as differential elastic backscatter, fluorescence, and depolarization in order to detect biological warfare agents (BWAs). However, because the release of BWAs in open air is forbidden, methods must be developed to predict candidate system performance against real agents. In support of such efforts, the Johns Hopkins University Applied Physics Lab (JHU/APL) has developed a modeling approach to predict the optical properties of agent materials from relatively simple, Biosafety Level 3-compatible bench top measurements. JHU/APL has fielded new ground truth instruments (in addition to standard particle sizers, such as the Aerodynamic particle sizer (APS) or GRIMM aerosol monitor (GRIMM)) to more thoroughly characterize the simulant aerosols released in recent field tests at Dugway Proving Ground (DPG). These instruments include the Scanning Mobility Particle Sizer (SMPS), the Ultraviolet Aerodynamic Particle Sizer (UVAPS), and the Aspect Aerosol Size and Shape Analyser (Aspect). The SMPS was employed as a means of measuring smallparticle concentrations for more accurate Mie scattering simulations; the UVAPS, which measures size-resolved fluorescence intensity, was employed as a path toward fluorescence cross section modeling; and the Aspect, which measures particle shape, was employed as a path towards depolarization modeling.

Health-related quality of life of Portuguese children and adolescents according to their biological maturation and volume of physical activity.

Science.gov (United States)

Garcia, Catarina; Teles, Júlia; Barrigas, Carlos; Fragoso, Isabel

2018-06-01

The purpose of this study was to analyze the relationship between biological maturation and health-related quality of life (HRQoL) in Portuguese children and adolescents of both sexes when the effect of chronological age (CA) and volume of physical activity (VPA) were removed. HRQoL, biological maturation, CA, and VPA were assessed in 750 children and adolescents, 11-17 years old, from 3 schools in Lisbon, Portugal. The KIDSCREEN-52 was used to assess HRQoL. Maturity indicator was bone age (BA), using Tanner-Whitehouse III method (TW3). The participants were classified into three different maturity categories: late, on time, and early maturers. VPA was assessed by questionnaire (RAPIL II). An analysis of covariance (ANCOVA), using the CA and the VPA as covariates was completed. The level of significance was set at p ≤ 0.05. Analysis of covariance suggested an influence of biological maturation in physical well-being dimension in both sexes, with early-maturing girls and boys having worst perception. Maturity groups were also influent in moods and emotions for girls. CA seems to be particularly important in self-perception and parent relation and home life for girls and in school environment for boys. Biological maturation and CA have relevant impact on some HRQoL dimensions. These variables, due to their nature and effect should be considered particularly when working with specific domains of HRQoL as physical well-being in both sexes, moods and emotions and self-perception and parent relation and home life for girls and in school environment for boys.

Physical and biological predictors of radiation-induced whole lung injury: early results of a prospective study

International Nuclear Information System (INIS)

Marks, L.B.; Munley, M.; Bentel, G.; Hollis, D.; Zhou, S.; Jirtle, R.; Kong, F.M.; Scarfone, C.; Antoine, P.; Chew, M.; Tapson, V.; Spencer, D.; Jaszczak, R.; Coleman, E.; Anscher, M.

1996-01-01

Purpose: To develop methods of predicting the pulmonary consequences of thoracic irradiation (RT) by prospectively studying changes in pulmonary function following RT. Methods: 105 patients receiving incidental partial lung irradiation during treatment of tumors in/around the thorax (lung-70, breast-18, lymphoma-4, misc-3) had whole lung function assessed (symptoms and pulmonary function tests [PFTs: FEV1-forced expiratory volume 1 sec; DLCO-diffusion capacity]) before and repeatedly 6-48 months following RT. All had computed tomography-based 3-dimensional (3D) dose calculations with lung density heterogeneity corrections for dose-volume histogram (DVH) and NTCP (normal tissue complication probability) calculations. Functional DVHs (DVfH) based on SPECT (single photon emission computed tomography) lung perfusion scans, and serial transforming growth factor-beta (TGF-β) levels were available in 50 and 30 patients, respectively. The incidence and severity of changes in whole lung function were correlated with clinical, physical and biological factors outlined in the results. Exploratory statistical analyses were preformed using chi-square, logistic regression, and multiple linear regression. Mean pt age=57, range 21-87; sex: 63 F, 42 M; 29 had chemotherapy (CT) before/with RT; Follow-up 6-48 months (mean 15, median 12). Results RT-induced symptoms developed in 26 patients (7-grade I-no intervention; 16 grade II-steroids; 3 grade III-oxygen and steroids). A mixed model based on pre-RT DLCO and CT-based NTCP was strongly predictive for the development of symptoms (p 30 Gy. In patients with 'good' pre-RT PFTs, there may be a relationship between the % reduction in PFT and % lung volume receiving >30 Gy (figure). Conclusion: Whole lung injury (symptoms or PFT changes) appears to be related to a variety of physical, biological and clinical factors. The data suggest that no one variable is likely to be an adequate predictor and that multi-faceted predictive models will be

Reactor physics methods development at Westinghouse

International Nuclear Information System (INIS)

Mueller, E.; Mayhue, L.; Zhang, B.

2007-01-01

The current state of reactor physics methods development at Westinghouse is discussed. The focus is on the methods that have been or are under development within the NEXUS project which was launched a few years ago. The aim of this project is to merge and modernize the methods employed in the PWR and BWR steady-state reactor physics codes of Westinghouse. (author)

Mixed-Methods Design in Biology Education Research: Approach and Uses.

Science.gov (United States)

Warfa, Abdi-Rizak M

Educational research often requires mixing different research methodologies to strengthen findings, better contextualize or explain results, or minimize the weaknesses of a single method. This article provides practical guidelines on how to conduct such research in biology education, with a focus on mixed-methods research (MMR) that uses both quantitative and qualitative inquiries. Specifically, the paper provides an overview of mixed-methods design typologies most relevant in biology education research. It also discusses common methodological issues that may arise in mixed-methods studies and ways to address them. The paper concludes with recommendations on how to report and write about MMR. © 2016 L. A.-R. M. Warfa. CBE—Life Sciences Education © 2016 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Foundations of anticipatory logic in biology and physics.

Science.gov (United States)

Bettinger, Jesse S; Eastman, Timothy E

2017-12-01

Recent advances in modern physics and biology reveal several scenarios in which top-down effects (Ellis, 2016) and anticipatory systems (Rosen, 1980) indicate processes at work enabling active modeling and inference such that anticipated effects project onto potential causes. We extrapolate a broad landscape of anticipatory systems in the natural sciences extending to computational neuroscience of perception in the capacity of Bayesian inferential models of predictive processing. This line of reasoning also comes with philosophical foundations, which we develop in terms of counterfactual reasoning and possibility space, Whitehead's process thought, and correlations with Eastern wisdom traditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Progress report, Biology and Health Physics Division, October 1 to December 31, 1975

International Nuclear Information System (INIS)

1976-01-01

Interim research results are reported in health physics (dosimetry, monitoring), environmental research, population research (tumor induction in mammals, human health record linkage), and biology (radiobiology of rodents, bacteria, bacteriophage T4, and insects). (E.C.B.)

Physical, chemical, and biological properties of radiocerium relevant to radiation protection guidelines

International Nuclear Information System (INIS)

Anon.

1978-01-01

Present knowledge of the relevant physical, chemical, and biological properties of radiocerium as a basis for establishing radiation protection guidelines is summarized. The first section of the report reviews the chemical and physical properties of radiocerium relative to the biological behavior of internally-deposited cerium and other lanthanides. The second section of the report gives the sources of radiocerium in the environment and the pathways to man. The third section of the report describes the metabolic fate of cerium in several mammalian species as a basis for predicting its metabolic fate in man. The fourth section of the report considers the biomedical effects of radiocerium in light of extensive animal experimentation. The last two sections of the report describe the history of radiation protection guidelines for radiocerium and summarize data required for evaluating the adequacy of current radiation protection guidelines. Each section begins with a summary of the most important findings that follow

A model of heavy ion detection in physical and biological systems

International Nuclear Information System (INIS)

Waligorski, M.P.R.

1988-01-01

Track structure theory (the Katz model) and its application to the detection of heavy ions in physical and biological systems are reviewed. Following the use of a new corrected formula describing the radial distribution of average dose around the path of a heavy ion, based on results of Monte Carlo calculations and on results of experimental measurements, better agreement is achieved between model calculations and experimentally measured relative effectiveness, for enzymatic and viral systems, for the Fricke dosemeter and for alanine and thermoluminescent (TDL-700) dosemeters irradiated with beams of heavy charged particles. From experimentally measured RBE dependences for survival and frequency of neoplastic transformations in a mammalian cell culture irradiated with beams of energetic heavy ions, values of model parameters for these biological endpoints have been extracted, and a model extrapolation to the low-dose region performed. Results of model calculations are then compared with evaluations of the lung cancer hazard in populations exposed to radon and its progeny. The model can be applied to practical phenomenological analysis of radiation damage in solid-state systems and to dosimetry of charged particle and fast neutron beams using a variety of detectors. The model can also serve as a guide in building more basic models of the action of ionizing radiation with physical and biological systems and guide of development of models of radiation risk more relevant than that used presently. 185 refs., 31 figs., 3 tabs. (author)

Progress report, Biology and Health Physics Division, July 1 to September 30, 1975

International Nuclear Information System (INIS)

1975-11-01

Interim results are reported for research in health physics, i.e. dosimetry, detectors, and monitoring; environmental research (limnology, radionuclide migration and kinetics; population research (radiation carcinogenesis, radiation effects in human populations); and biology (radiobiology). (E.C.B.)

Nuclear methods in medical physics

International Nuclear Information System (INIS)

Jeraj, R.

2003-01-01

A common ground for both, reactor and medical physics is a demand for high accuracy of particle transport calculations. In reactor physics, safe operation of nuclear power plants has been asking for high accuracy of calculation methods. Similarly, dose calculation in radiation therapy for cancer has been requesting high accuracy of transport methods to ensure adequate dosimetry. Common to both problems has always been a compromise between achievable accuracy and available computer power leading into a variety of calculation methods developed over the decades. On the other hand, differences of subjects (nuclear reactor vs. humans) and radiation types (neutron/photon vs. photon/electron or ions) are calling for very field-specific approach. Nevertheless, it is not uncommon to see drift of researches from one field to another. Several examples from both fields will be given with the aim to compare the problems, indicating their similarities and discussing their differences. As examples of reactor physics applications, both deterministic and Monte Carlo calculations will be presented for flux distributions of the VENUS and TRIGA Mark II benchmark. These problems will be paralleled to medical physics applications in linear accelerator radiation field determination and dose distribution calculations. Applicability of the adjoint/forward transport will be discussed in the light of both transport problems. Boron neutron capture therapy (BNCT) as an example of the close collaboration between the fields will be presented. At last, several other examples from medical physics, which can and cannot find corresponding problems in reactor physics, will be discussed (e.g., beam optimisation in inverse treatment planning, imaging applications). (author)

Computational Methods in Plasma Physics

CERN Document Server

Jardin, Stephen

2010-01-01

Assuming no prior knowledge of plasma physics or numerical methods, Computational Methods in Plasma Physics covers the computational mathematics and techniques needed to simulate magnetically confined plasmas in modern magnetic fusion experiments and future magnetic fusion reactors. Largely self-contained, the text presents the basic concepts necessary for the numerical solution of partial differential equations. Along with discussing numerical stability and accuracy, the author explores many of the algorithms used today in enough depth so that readers can analyze their stability, efficiency,

Progress report, Biology and Health Physics Division, April 1 to June 30, 1975

International Nuclear Information System (INIS)

1975-09-01

Interim results are reported on research at CRNL in health physics (dosimetry, instrumentation, monitoring); environmental research (limnology, radionuclide migration and kinetics); populaton research (tumor induction in mammals, human health records); and biology (radiobiology, genetic studies). (E.C.B.)

Tritium in the Physical and Biological Sciences. Vol. II. Proceedings of the Symposium on the Detection and Use of Tritium in the Physical and Biological Sciences

Energy Technology Data Exchange (ETDEWEB)

NONE

1962-02-15

The use of tritium for research in physics, chemistry, biology and hydrology has in recent years become increasingly important. It was for this reason that the first international conference to discuss the progress of new developments was organized by the IAEA in conjunction with the Joint Commission on Applied Radioactivity and held from 3 - 10 May 1961, in Vienna. The first five sessions of the Symposium were devoted to the use of tritium in hydrology, physics and chemistry. Special emphasis was laid on the role of tritium as a tracer in hydrology, especially in the study of water movement. The establishment and improvement of counting and detection techniques to facilitate the application of tritium as a tracer was another aspect discussed in this part of the proceedings. Papers were read on the preparation of tritiated compounds and it was generally agreed that further clarification of the mechanism of various techniques, and of the Wilzbach gas exposure technique in particular, would lead to further developments in the synthesis of a number of tritium compounds important in biology. Other papers were concerned with tritium applications to studies of the mechanism of some chemical reactions together with the effects of tritium isotopes. During the second part of the Symposium the biological applications of tritium and tritiated compounds were discussed. These included general problems connected with the biological uses of tritium and the radiation effects of tritium on living organisms such as viruses, bacteria and cancer cells. The value of tritium in biological studies became apparent because of the ease with which a large number of metabolically active compounds such as hormones, vitamins and other important constituents in the body can be labelled with tritium. Tritium is also a weak beta-emitter and autoradiographs of tissues and single cells containing tritium-labelled compounds allow an excellent localization of the tracer. The Symposium was attended by

Tritium in the Physical and Biological Sciences. Vol. II. Proceedings of the Symposium on the Detection and Use of Tritium in the Physical and Biological Sciences

International Nuclear Information System (INIS)

1962-01-01

The use of tritium for research in physics, chemistry, biology and hydrology has in recent years become increasingly important. It was for this reason that the first international conference to discuss the progress of new developments was organized by the IAEA in conjunction with the Joint Commission on Applied Radioactivity and held from 3 — 10 May 1961, in Vienna. The first five sessions of the Symposium were devoted to the use of tritium in hydrology, physics and chemistry. Special emphasis was laid on the role of tritium as a tracer in hydrology, especially in the study of water movement. The establishment and improvement of counting and detection techniques to facilitate the application of tritium as a tracer was another aspect discussed in this part of the proceedings. Papers were read on the preparation of tritiated compounds and it was generally agreed that further clarification of the mechanism of various techniques, and of the Wilzbach gas exposure technique in particular, would lead to further developments in the synthesis of a number of tritium compounds important in biology. Other papers were concerned with tritium applications to studies of the mechanism of some chemical reactions together with the effects of tritium isotopes. During the second part of the Symposium the biological applications of tritium and tritiated compounds were discussed. These included general problems connected with the biological uses of tritium and the radiation effects of tritium on living organisms such as viruses, bacteria and cancer cells. The value of tritium in biological studies became apparent because of the ease with which a large number of metabolically active compounds such as hormones, vitamins and other important constituents in the body can be labelled with tritium. Tritium is also a weak beta-emitter and autoradiographs of tissues and single cells containing tritium-labelled compounds allow an excellent localization of the tracer. The Symposium was attended

Qualitative methods in theoretical physics

CERN Document Server

Maslov, Dmitrii

2018-01-01

This book comprises a set of tools which allow researchers and students to arrive at a qualitatively correct answer without undertaking lengthy calculations. In general, Qualitative Methods in Theoretical Physics is about combining approximate mathematical methods with fundamental principles of physics: conservation laws and symmetries. Readers will learn how to simplify problems, how to estimate results, and how to apply symmetry arguments and conduct dimensional analysis. A comprehensive problem set is included. The book will appeal to a wide range of students and researchers.

TH-A-19A-05: Modeling Physics Properties and Biologic Effects Induced by Proton and Helium Ions

Energy Technology Data Exchange (ETDEWEB)

Taleei, R; Titt, U; Peeler, C; Guan, F; Mirkovic, D; Grosshans, D; Mohan, R [UT MD Anderson Cancer Center, Houston, TX (United States)

2014-06-15

Purpose: Currently, proton and carbon ions are used for cancer treatment. More recently, other light ions including helium ions have shown interesting physical and biological properties. The purpose of this work is to study the biological and physical properties of helium ions (He-3) in comparison to protons. Methods: Monte Carlo simulations with FLUKA, GEANT4 and MCNPX were used to calculate proton and He-3 dose distributions in water phantoms. The energy spectra of proton and He-3 beams were calculated with high resolution for use in biological models. The repair-misrepairfixation (RMF) model was subsequently used to calculate the RBE. Results: The proton Bragg curve calculations show good agreement between the three general purpose Monte Carlo codes. In contrast, the He-3 Bragg curve calculations show disagreement (for the magnitude of the Bragg peak) between FLUKA and the other two Monte Carlo codes. The differences in the magnitude of the Bragg peak are mainly due to the discrepancy in the secondary fragmentation cross sections used by the codes. The RBE for V79 cell lines is about 0.96 and 0.98 at the entrance of proton and He-3 ions depth dose respectively. The RBE increases to 1.06 and 1.59 at the Bragg peak of proton and He-3 ions. The results demonstrated that LET, microdosimetric parameters (such as dose-mean lineal energy) and RBE are nearly constant along the plateau region of Bragg curve, while all parameters increase within the Bragg peak and at the distal edge for both proton and He-3 ions. Conclusion: The Monte Carlo codes should revise the fragmentation cross sections to more accurately simulate the physical properties of He-3 ions. The increase in RBE for He-3 ions is higher than for proton beams at the Bragg peak.

Department of Nuclear Methods in the Solid State Physics

International Nuclear Information System (INIS)

2002-01-01

Full text: The activity of the Department of Nuclear Methods in the Solid State Physics is focused on experimental research in condensed matter physics. Thermal neutron scattering and Moessbauer effect are the main techniques mastered in the laboratory. Most of the studies aim at better understanding of properties and processes observed in modern materials. Some applied research and theoretical studies were also performed. Research activities of the Department in 2001 can be summarized as follows: Neutron scattering studies concerned the magnetic ordering in TbB 12 and TmIn 3 and some special features of magnetic excitations in antiferromagnetic γ-Mn-alloys. Some work was devoted to optimization of the neutron single crystal monochromators and polarizers grown in Crystal Growth Laboratory. Small angle scattering studies on the surfactant - water ternary system were performed in cooperation with JINR Dubna. Moessbauer effect investigations of dysprosium intermetallic compounds yielded the new data for Pauling-Slater curves. The same technique applied to perovskites and ferrocene adduct to fullerene helped to resolve their structure. X-ray topographic and diffractometric studies were performed on hydrogen implanted semiconductor surfaces employing the synchrotron radiation sources. The X-ray method was applied also to investigations of plasma spraying process and phase composition of ceramic oxide coatings. Large part of studies concerned the structure of biologically active, pharmacologically important organic complexes, supported by modeling of their electron structure. Crystal growth of large size single-crystals of metals and alloys was used for preparation of specimens with mosaic structure suitable for neutron monochromator and polarizer systems. The construction work of the Neutron and Gamma Radiography Station has been completed. The results of first tests and studies proved the expected abilities of the systems. The possibility to visualize inner structures

Neutron dosimetry in biology

International Nuclear Information System (INIS)

Sigurbjoernsson, B.; Smith, H.H.; Gustafsson, A.

1965-01-01

To study adequately the biological effects of different energy neutrons it is necessary to have high-intensity sources which are not contaminated by other radiations, the most serious of which are gamma rays. An effective dosimetry must provide an accurate measure of the absorbed dose, in biological materials, of each type of radiation at any reactor facility involved in radiobiological research. A standardized biological dosimetry, in addition to physical and chemical methods, may be desirable. The ideal data needed to achieve a fully documented dosimetry has been compiled by H. Glubrecht: (1) Energy spectrum and intensity of neutrons; (2) Angular distribution of neutrons on the whole surface of the irradiated object; (3) Additional undesired radiation accompanying the neutrons; (4) Physical state and chemical composition of the irradiated object. It is not sufficient to note only an integral dose value (e.g. in 'rad') as the biological effect depends on the above data

Where Is Earth Science? Mining for Opportunities in Chemistry, Physics, and Biology

Science.gov (United States)

Thomas, Julie; Ivey, Toni; Puckette, Jim

2013-01-01

The Earth sciences are newly marginalized in K-12 classrooms. With few high schools offering Earth science courses, students' exposure to the Earth sciences relies on the teacher's ability to incorporate Earth science material into a biology, chemistry, or physics course. ''G.E.T. (Geoscience Experiences for Teachers) in the Field'' is an…

RENEB - Running the European Network of biological dosimetry and physical retrospective dosimetry.

Science.gov (United States)

Kulka, Ulrike; Abend, Michael; Ainsbury, Elizabeth; Badie, Christophe; Barquinero, Joan Francesc; Barrios, Lleonard; Beinke, Christina; Bortolin, Emanuela; Cucu, Alexandra; De Amicis, Andrea; Domínguez, Inmaculada; Fattibene, Paola; Frøvig, Anne Marie; Gregoire, Eric; Guogyte, Kamile; Hadjidekova, Valeria; Jaworska, Alicja; Kriehuber, Ralf; Lindholm, Carita; Lloyd, David; Lumniczky, Katalin; Lyng, Fiona; Meschini, Roberta; Mörtl, Simone; Della Monaca, Sara; Monteiro Gil, Octávia; Montoro, Alegria; Moquet, Jayne; Moreno, Mercedes; Oestreicher, Ursula; Palitti, Fabrizio; Pantelias, Gabriel; Patrono, Clarice; Piqueret-Stephan, Laure; Port, Matthias; Prieto, María Jesus; Quintens, Roel; Ricoul, Michelle; Romm, Horst; Roy, Laurence; Sáfrány, Géza; Sabatier, Laure; Sebastià, Natividad; Sommer, Sylwester; Terzoudi, Georgia; Testa, Antonella; Thierens, Hubert; Turai, Istvan; Trompier, François; Valente, Marco; Vaz, Pedro; Voisin, Philippe; Vral, Anne; Woda, Clemens; Zafiropoulos, Demetre; Wojcik, Andrzej

2017-01-01

A European network was initiated in 2012 by 23 partners from 16 European countries with the aim to significantly increase individualized dose reconstruction in case of large-scale radiological emergency scenarios. The network was built on three complementary pillars: (1) an operational basis with seven biological and physical dosimetric assays in ready-to-use mode, (2) a basis for education, training and quality assurance, and (3) a basis for further network development regarding new techniques and members. Techniques for individual dose estimation based on biological samples and/or inert personalized devices as mobile phones or smart phones were optimized to support rapid categorization of many potential victims according to the received dose to the blood or personal devices. Communication and cross-border collaboration were also standardized. To assure long-term sustainability of the network, cooperation with national and international emergency preparedness organizations was initiated and links to radiation protection and research platforms have been developed. A legal framework, based on a Memorandum of Understanding, was established and signed by 27 organizations by the end of 2015. RENEB is a European Network of biological and physical-retrospective dosimetry, with the capacity and capability to perform large-scale rapid individualized dose estimation. Specialized to handle large numbers of samples, RENEB is able to contribute to radiological emergency preparedness and wider large-scale research projects.

Physical descriptions of the bacterial nucleoid at large scales, and their biological implications

Energy Technology Data Exchange (ETDEWEB)

Benza, Vincenzo G [Dipartimento di Fisica e Matematica, Universita dell' Insubria, Como (Italy); Bassetti, Bruno [Universita degli Studi di Milano, Dip. Fisica, Via Celoria 16, 20133 Milano (Italy); Dorfman, Kevin D [Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Ave. SE, Minneapolis, MN 55455 (United States); Scolari, Vittore F; Lagomarsino, Marco Cosentino [CNRS, UMR 7238 ' Microorganism Genomics' , Genomic Physics Group (France); Bromek, Krystyna; Cicuta, Pietro [Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE (United Kingdom)

2012-07-15

Recent experimental and theoretical approaches have attempted to quantify the physical organization (compaction and geometry) of the bacterial chromosome with its complement of proteins (the nucleoid). The genomic DNA exists in a complex and dynamic protein-rich state, which is highly organized at various length scales. This has implications for modulating (when not directly enabling) the core biological processes of replication, transcription and segregation. We overview the progress in this area, driven in the last few years by new scientific ideas and new interdisciplinary experimental techniques, ranging from high space- and time-resolution microscopy to high-throughput genomics employing sequencing to map different aspects of the nucleoid-related interactome. The aim of this review is to present the wide spectrum of experimental and theoretical findings coherently, from a physics viewpoint. In particular, we highlight the role that statistical and soft condensed matter physics play in describing this system of fundamental biological importance, specifically reviewing classic and more modern tools from the theory of polymers. We also discuss some attempts toward unifying interpretations of the current results, pointing to possible directions for future investigation. (review article)

Physical, chemical and biological studies of gelatin/chitosan based transdermal fims with embedded silver nanoparticles

Directory of Open Access Journals (Sweden)

Sneha Paul

2015-12-01

Full Text Available Objective: To study the physical, chemical and biological properties of composite chitosangelatin transdermal film along with silver nanoparticles as binding agent and determine the compatibility of the prepared amalgamation towards wound management. Methods: Transdermal film preparations were done by solvent casting method containing different concentrations of biological synthesized silver nanoparticles. The films were characterized by using scanning electron microscope for their morphology and the determination of silver metal was done by using inductively coupled plasma atomic emission spectroscopy. Then a quantity of silver nanoparticles was further proceeded by physiochemical parameters (weight, thickness, temperature, solubility, absorption, tensile strength, in vitro drug release and skin permeation and biological parameters studies (anti-microbial, cytotoxicity and reactive oxygen species. Results: The film prepared by utilizing 2 g of gelatin and 0.5 g of chitosan exhibited better results. The physiochemical parameters studies revealed higher concentration of silver nanoparticles would give better results. In vitro drug release studies through dialysis and skin permeation showed the release of drug versus time (h. These films had shown excellent inhibition against Streptococcus and Escherichia coli species. Cytotoxicity study by MTT indicated the mild toxicity existed as the concentration of silver nanoparticles increased. Reactive oxygen species generation studies of transdermal film by using 2'7'-dichlorofluorescein diacetate assay demonstrated that the fluorescent cells were found in the higher concentration, which indicated cell damage (reactive oxygen species generated. Conclusions: Based on these observations, in vitro performances against various characteristics of transdermal film, would be utilized as a distinct dressing material and patches accessible in market.

Physical biological coupling in the Pearl River Estuary

Science.gov (United States)

Harrison, Paul J.; Yin, Kedong; Lee, J. H. W.; Gan, Jianping; Liu, Hongbin

2008-07-01

The Pearl River Estuary is a subtropical estuary and the second largest in China based on discharge volume from the Pearl River. Processes in the estuary vary spatially and temporally (wet vs dry season). In the dry season at the head of the estuary, hypoxic and nearly anoxic conditions occur and NH 4 reaches >600 μM, NO 3 is ˜300 μM and nitrite is ˜60 μM indicating that nitrification and denitrification may be important dry season processes in the region extending 40 km upstream of the Humen outlet. There are very few biological studies conducted in this upper section of the estuary in either the dry or wet seasons and hence there is a need for further research in this region of the river. In the wet season, the salinity wedge extends to the Hongqimen outlet and oxygen is low (35-80% saturation). Nitrate is ˜100 μM, silicate ˜140 μM; and phosphate is relatively low at ˜0.5 μM, yielding an N:P ratio up to ˜200:1 in summer. Nutrients decrease in the lower estuary and primary productivity may become potentially P-limited. Eutrophication is not as severe as one would expect from the nutrient inputs from the Pearl River and from Hong Kong's sewage discharge. This estuary shows a remarkable capacity to cope with excessive nutrients. Physical processes such as river discharge, tidal flushing, turbulent dispersion, wind-induced mixing, and estuarine circulation play an important role in controlling the production and accumulation of algal blooms and the potential occurrence of hypoxia. Superimposed on the physical processes of the estuary are the chemical and biological processes involved in the production of the bloom. For example, the 100N:1P ratio indicates that P potentially limits the amount of algal biomass (and potential biological oxygen demand) in summer. While extended periods of hypoxia are rare in Hong Kong waters, episodic events have been reported to occur during late summer due to factors such as low wind, high rainfall and river discharge which

Methods of modern mathematical physics

CERN Document Server

Reed, Michael

1980-01-01

This book is the first of a multivolume series devoted to an exposition of functional analysis methods in modern mathematical physics. It describes the fundamental principles of functional analysis and is essentially self-contained, although there are occasional references to later volumes. We have included a few applications when we thought that they would provide motivation for the reader. Later volumes describe various advanced topics in functional analysis and give numerous applications in classical physics, modern physics, and partial differential equations.

Radiation physics, biophysics and radiation biology. Progress report, October 1, 1980-September 30, 1981

International Nuclear Information System (INIS)

1981-07-01

Separate abstracts were prepared for the 29 papers in this progress report which deal with radiobiological physics, the biological effects of ionizing radiations, and the modification of these effects by chemical and pharmacological agents

Definition of means and methods for physical training of 3–6 years old children taking into account their individual development and physical fitness

Directory of Open Access Journals (Sweden)

Tеtіana Dorofieieva

2017-06-01

Full Text Available Purpose: definition and justification features of the physical development 3–6 years old children and the features of physical preparedness of this age period. Material & Methods: the sample size for each age group was 100 persons. For an objective assessment of the characteristics considered, the concepts of biological age and passport age are introduced as indispensable indicators for determining individual characteristics of the organism development. Results: based on the administration of the two criteria for age estimation takes into account features of construction of motor activity. For the orderly presentation of the obtained individual features of the organization of motor activity characteristics used indicative of semantic space. This allowed us to establish the regularities of the processes under consideration and their approximation by mathematical equations. Presence of analytical descriptions allows to provide forecasting of development and to carry out professional selection of persons possessing a certain motor talent. Results and their presentation are published for the first time. Conclusion: to build a system for monitoring physical fitness and physical preparedness, systematic monitoring is necessary, in which the assessment of the biological age and the individual structure of the somatotype. Based on the representation of the observations obtained in the semantic spaces, regularities of the morphological and functional forms of the child somatotype.

The universal numbers. From Biology to Physics.

Science.gov (United States)

Marchal, Bruno

2015-12-01

I will explain how the mathematicians have discovered the universal numbers, or abstract computer, and I will explain some abstract biology, mainly self-reproduction and embryogenesis. Then I will explain how and why, and in which sense, some of those numbers can dream and why their dreams can glue together and must, when we assume computationalism in cognitive science, generate a phenomenological physics, as part of a larger phenomenological theology (in the sense of the greek theologians). The title should have been "From Biology to Physics, through the Phenomenological Theology of the Universal Numbers", if that was not too long for a title. The theology will consist mainly, like in some (neo)platonist greek-indian-chinese tradition, in the truth about numbers' relative relations, with each others, and with themselves. The main difference between Aristotle and Plato is that Aristotle (especially in its common and modern christian interpretation) makes reality WYSIWYG (What you see is what you get: reality is what we observe, measure, i.e. the natural material physical science) where for Plato and the (rational) mystics, what we see might be only the shadow or the border of something else, which might be non physical (mathematical, arithmetical, theological, …). Since Gödel, we know that Truth, even just the Arithmetical Truth, is vastly bigger than what the machine can rationally justify. Yet, with Church's thesis, and the mechanizability of the diagonalizations involved, machines can apprehend this and can justify their limitations, and get some sense of what might be true beyond what they can prove or justify rationally. Indeed, the incompleteness phenomenon introduces a gap between what is provable by some machine and what is true about that machine, and, as Gödel saw already in 1931, the existence of that gap is accessible to the machine itself, once it is has enough provability abilities. Incompleteness separates truth and provable, and machines can

Natural physical and biological processes compromise the long-term performance of compacted soil caps

International Nuclear Information System (INIS)

Smith, E.D.

1995-01-01

Compacted soil barriers are components of essentially all caps placed on closed waste disposal sites. The intended functions of soil barriers in waste facility caps include restricting infiltration of water and release of gases and vapors, either independently or in combination with synthetic membrane barriers, and protecting other manmade or natural barrier components. Review of the performance of installed soil barriers and of natural processes affecting their performance indicates that compacted soil caps may function effectively for relatively short periods (years to decades), but natural physical and biological processes can be expected to cause them to fail in the long term (decades to centuries). This paper addresses natural physical and biological processes that compromise the performance of compacted soil caps and suggests measures that may reduce the adverse consequences of these natural failure mechanisms

Ultrasonic methods in solid state physics

CERN Document Server

Truell, John; Elbaum, Charles

1969-01-01

Ultrasonic Methods in Solid State Physics is devoted to studies of energy loss and velocity of ultrasonic waves which have a bearing on present-day problems in solid-state physics. The discussion is particularly concerned with the type of investigation that can be carried out in the megacycle range of frequencies from a few megacycles to kilomegacycles; it deals almost entirely with short-duration pulse methods rather than with standing-wave methods. The book opens with a chapter on a classical treatment of wave propagation in solids. This is followed by separate chapters on methods and techni

Biological vs. physical mixing effects on benthic food web dynamics.

Directory of Open Access Journals (Sweden)

Ulrike Braeckman

Full Text Available Biological particle mixing (bioturbation and solute transfer (bio-irrigation contribute extensively to ecosystem functioning in sediments where physical mixing is low. Macrobenthos transports oxygen and organic matter deeper into the sediment, thereby likely providing favourable niches to lower trophic levels (i.e., smaller benthic animals such as meiofauna and bacteria and thus stimulating mineralisation. Whether this biological transport facilitates fresh organic matter assimilation by the metazoan lower part of the food web through niche establishment (i.e., ecosystem engineering or rather deprives them from food sources, is so far unclear. We investigated the effects of the ecosystem engineers Lanice conchilega (bio-irrigator and Abra alba (bioturbator compared to abiotic physical mixing events on survival and food uptake of nematodes after a simulated phytoplankton bloom. The (13C labelled diatom Skeletonema costatum was added to 4 treatments: (1 microcosms containing the bioturbator, (2 microcosms containing the bio-irrigator, (3 control microcosms and (4 microcosms with abiotic manual surface mixing. Nematode survival and subsurface peaks in nematode density profiles were most pronounced in the bio-irrigator treatment. However, nematode specific uptake (Δδ(13C of the added diatoms was highest in the physical mixing treatment, where macrobenthos was absent and the diatom (13C was homogenised. Overall, nematodes fed preferentially on bulk sedimentary organic material rather than the added diatoms. The total C budget (µg C m(-2, which included TO(13C remaining in the sediment, respiration, nematode and macrobenthic uptake, highlighted the limited assimilation by the metazoan benthos and the major role of bacterial respiration. In summary, bioturbation and especially bio-irrigation facilitated the lower trophic levels mainly over the long-term through niche establishment. Since the freshly added diatoms represented only a limited food

Nuclear physics mathematical methods

International Nuclear Information System (INIS)

Balian, R.; Gervois, A.; Giannoni, M.J.; Levesque, D.; Maille, M.

1984-01-01

The nuclear physics mathematical methods, applied to the collective motion theory, to the reduction of the degrees of freedom and to the order and disorder phenomena; are investigated. In the scope of the study, the following aspects are discussed: the entropy of an ensemble of collective variables; the interpretation of the dissipation, applying the information theory; the chaos and the universality; the Monte-Carlo method applied to the classical statistical mechanics and quantum mechanics; the finite elements method, and the classical ergodicity [fr

Non-ionizing radiations : physical characteristics, biological effects and health hazard assessment

International Nuclear Information System (INIS)

Repacholi, M.H.

1988-01-01

The Workshop was a project of the International Non-Ionizing Radiation Committee of IRPA and comprised a series of educational lectures and demonstrations intended to give a comprehensive overview of non-ionizing electromagnetic radiation: physical characteristics, sources of concern, levels of exposure, mechanisms of interaction and reported effects of these fields and radiations with biological tissues, human studies, health risk assessment, national and international standards and guidelines, and protective measures

Physical Methods for Seed Invigoration: Advantages and Challenges in Seed Technology.

Science.gov (United States)

Araújo, Susana de Sousa; Paparella, Stefania; Dondi, Daniele; Bentivoglio, Antonio; Carbonera, Daniela; Balestrazzi, Alma

2016-01-01

In the context of seed technology, the use of physical methods for increasing plant production offers advantages over conventional treatments based on chemical substances. The effects of physical invigoration treatments in seeds can be now addressed at multiple levels, ranging from morpho-structural aspects to changes in gene expression and protein or metabolite accumulation. Among the physical methods available, "magneto-priming" and irradiation with microwaves (MWs) or ionizing radiations (IRs) are the most promising pre-sowing seed treatments. "Magneto-priming" is based on the application of magnetic fields and described as an eco-friendly, cheap, non-invasive technique with proved beneficial effects on seed germination, vigor and crop yield. IRs, as γ-rays and X-rays, have been widely regarded as a powerful tool in agricultural sciences and food technology. Gamma-rays delivered at low dose have showed to enhance germination percentage and seedling establishment, acting as an actual 'priming' treatment. Different biological effects have been observed in seeds subjected to MWs and X-rays but knowledge about their impact as seed invigoration agent or stimulatory effects on germination need to be further extended. Ultraviolet (UV) radiations, namely UV-A and UV-C have shown to stimulate positive impacts on seed health, germination, and seedling vigor. For all mentioned physical treatments, extensive fundamental and applied research is still needed to define the optimal dose, exposition time, genotype- and environment-dependent irradiation conditions. Electron paramagnetic resonance has an enormous potential in seed technology not fully explored to monitor seed invigoration treatments and/or identifying the best suitable irradiation dose or time-point to stop the treatment. The present manuscript describes the use of physical methods for seed invigoration, while providing a critical discussion on the constraints and advantages. The future perspectives related to

Physical Methods for Seed Invigoration: Advantages and Challenges in Seed Technology

Science.gov (United States)

Araújo, Susana de Sousa; Paparella, Stefania; Dondi, Daniele; Bentivoglio, Antonio; Carbonera, Daniela; Balestrazzi, Alma

2016-01-01

In the context of seed technology, the use of physical methods for increasing plant production offers advantages over conventional treatments based on chemical substances. The effects of physical invigoration treatments in seeds can be now addressed at multiple levels, ranging from morpho-structural aspects to changes in gene expression and protein or metabolite accumulation. Among the physical methods available, “magneto-priming” and irradiation with microwaves (MWs) or ionizing radiations (IRs) are the most promising pre-sowing seed treatments. “Magneto-priming” is based on the application of magnetic fields and described as an eco-friendly, cheap, non-invasive technique with proved beneficial effects on seed germination, vigor and crop yield. IRs, as γ-rays and X-rays, have been widely regarded as a powerful tool in agricultural sciences and food technology. Gamma-rays delivered at low dose have showed to enhance germination percentage and seedling establishment, acting as an actual ‘priming’ treatment. Different biological effects have been observed in seeds subjected to MWs and X-rays but knowledge about their impact as seed invigoration agent or stimulatory effects on germination need to be further extended. Ultraviolet (UV) radiations, namely UV-A and UV-C have shown to stimulate positive impacts on seed health, germination, and seedling vigor. For all mentioned physical treatments, extensive fundamental and applied research is still needed to define the optimal dose, exposition time, genotype- and environment-dependent irradiation conditions. Electron paramagnetic resonance has an enormous potential in seed technology not fully explored to monitor seed invigoration treatments and/or identifying the best suitable irradiation dose or time-point to stop the treatment. The present manuscript describes the use of physical methods for seed invigoration, while providing a critical discussion on the constraints and advantages. The future perspectives

Physical methods for seed vigourization: advantages and challenges in seed technology

Directory of Open Access Journals (Sweden)

Susana eAraújo

2016-05-01

Full Text Available In the context of seed technology, the use of physical methods for increasing plant production offers advantages over conventional treatments based on chemical substances. The effects of physical vigourization treatments in seeds can be now addressed at multiple levels, ranging from morpho-structural aspects to changes in gene expression and protein or metabolite accumulation. Among the physical methods available, magneto-priming and irradiation with microwaves or ionizing radiations are the most promissory pre-sowing seed treatments. Magneto-priming is based on the application of magnetic fields and described as an eco-friendly, cheap, non-invasive technique with proved beneficial effects on seed germination, vigour and crop yield. Ionizing radiations, as gamma-rays and X-rays, have been widely regarded as a powerful tool in agricultural sciences and food technology. Gamma-rays delivered at low dose have showed to enhance germination percentage and seedling establishment, acting as an actual ‘priming’ treatment. Different biological effects have been observed in seeds subjected to microwaves and X-rays but knowledge about their impact as seed vigourization agent or stimulatory effects on germination need to be further extended. Ultraviolet (UV radiations, namely UV-A and UV-C have shown to stimulate positive impacts on seed health, germination and seedling vigour. For all mentioned physical treatments, extensive fundamental and applied research is still needed to define the optimal dose, exposition time, genotype- and environment-dependent irradiation conditions. Electron paramagnetic resonance (EPR has an enormous potential in seed technology not fully explored to monitor seed vigourization treatments and/or identifying the best suitable irradiation dose or time-point to stop the treatment. The present manuscript describes the use of physical methods for seed vigourization, while providing a critical discussion on the constraints and

Marriages of mathematics and physics: A challenge for biology.

Science.gov (United States)

Islami, Arezoo; Longo, Giuseppe

2017-12-01

The human attempts to access, measure and organize physical phenomena have led to a manifold construction of mathematical and physical spaces. We will survey the evolution of geometries from Euclid to the Algebraic Geometry of the 20th century. The role of Persian/Arabic Algebra in this transition and its Western symbolic development is emphasized. In this relation, we will also discuss changes in the ontological attitudes toward mathematics and its applications. Historically, the encounter of geometric and algebraic perspectives enriched the mathematical practices and their foundations. Yet, the collapse of Euclidean certitudes, of over 2300 years, and the crisis in the mathematical analysis of the 19th century, led to the exclusion of "geometric judgments" from the foundations of Mathematics. After the success and the limits of the logico-formal analysis, it is necessary to broaden our foundational tools and re-examine the interactions with natural sciences. In particular, the way the geometric and algebraic approaches organize knowledge is analyzed as a cross-disciplinary and cross-cultural issue and will be examined in Mathematical Physics and Biology. We finally discuss how the current notions of mathematical (phase) "space" should be revisited for the purposes of life sciences. Copyright © 2017. Published by Elsevier Ltd.

Mixed-Methods Design in Biology Education Research: Approach and Uses

Science.gov (United States)

Warfa, Abdi-Rizak M.

2016-01-01

Educational research often requires mixing different research methodologies to strengthen findings, better contextualize or explain results, or minimize the weaknesses of a single method. This article provides practical guidelines on how to conduct such research in biology education, with a focus on mixed-methods research (MMR) that uses both quantitative and qualitative inquiries. Specifically, the paper provides an overview of mixed-methods design typologies most relevant in biology education research. It also discusses common methodological issues that may arise in mixed-methods studies and ways to address them. The paper concludes with recommendations on how to report and write about MMR. PMID:27856556

Using Cluster Analysis to Compartmentalize a Large Managed Wetland Based on Physical, Biological, and Climatic Geospatial Attributes.

Science.gov (United States)

Hahus, Ian; Migliaccio, Kati; Douglas-Mankin, Kyle; Klarenberg, Geraldine; Muñoz-Carpena, Rafael

2018-04-27

Hierarchical and partitional cluster analyses were used to compartmentalize Water Conservation Area 1, a managed wetland within the Arthur R. Marshall Loxahatchee National Wildlife Refuge in southeast Florida, USA, based on physical, biological, and climatic geospatial attributes. Single, complete, average, and Ward's linkages were tested during the hierarchical cluster analyses, with average linkage providing the best results. In general, the partitional method, partitioning around medoids, found clusters that were more evenly sized and more spatially aggregated than those resulting from the hierarchical analyses. However, hierarchical analysis appeared to be better suited to identify outlier regions that were significantly different from other areas. The clusters identified by geospatial attributes were similar to clusters developed for the interior marsh in a separate study using water quality attributes, suggesting that similar factors have influenced variations in both the set of physical, biological, and climatic attributes selected in this study and water quality parameters. However, geospatial data allowed further subdivision of several interior marsh clusters identified from the water quality data, potentially indicating zones with important differences in function. Identification of these zones can be useful to managers and modelers by informing the distribution of monitoring equipment and personnel as well as delineating regions that may respond similarly to future changes in management or climate.

The biology and polymer physics underlying large-scale chromosome organization.

Science.gov (United States)

Sazer, Shelley; Schiessel, Helmut

2018-02-01

Chromosome large-scale organization is a beautiful example of the interplay between physics and biology. DNA molecules are polymers and thus belong to the class of molecules for which physicists have developed models and formulated testable hypotheses to understand their arrangement and dynamic properties in solution, based on the principles of polymer physics. Biologists documented and discovered the biochemical basis for the structure, function and dynamic spatial organization of chromosomes in cells. The underlying principles of chromosome organization have recently been revealed in unprecedented detail using high-resolution chromosome capture technology that can simultaneously detect chromosome contact sites throughout the genome. These independent lines of investigation have now converged on a model in which DNA loops, generated by the loop extrusion mechanism, are the basic organizational and functional units of the chromosome. © 2017 The Authors. Traffic published by John Wiley & Sons Ltd.

Environmental parameters of the Tennessee River in Alabama. 2: Physical, chemical, and biological parameters. [biological and chemical effects of thermal pollution from nuclear power plants on water quality

Science.gov (United States)

Rosing, L. M.

1976-01-01

Physical, chemical and biological water quality data from five sites in the Tennessee River, two in Guntersville Reservoir and three in Wheeler Reservoir were correlated with climatological data for three annual cycles. Two of the annual cycles are for the years prior to the Browns Ferry Nuclear Power Plant operations and one is for the first 14 months of Plant operations. A comparison of the results of the annual cycles indicates that two distinct physical conditions in the reservoirs occur, one during the warm months when the reservoirs are at capacity and one during the colder winter months when the reservoirs have been drawn-down for water storage during the rainy months and for weed control. The wide variations of physical and chemical parameters to which the biological organisms are subjected on an annual basis control the biological organisms and their population levels. A comparison of the parameters of the site below the Power plant indicates that the heated effluent from the plant operating with two of the three reactors has not had any effect on the organisms at this site. Recommendations given include the development of prediction mathematical models (statistical analysis) for the physical and chemical parameters under specific climatological conditions which affect biological organisms. Tabulated data of chemical analysis of water and organism populations studied is given.

Methods of statistical physics

CERN Document Server

Akhiezer, Aleksandr I

1981-01-01

Methods of Statistical Physics is an exposition of the tools of statistical mechanics, which evaluates the kinetic equations of classical and quantized systems. The book also analyzes the equations of macroscopic physics, such as the equations of hydrodynamics for normal and superfluid liquids and macroscopic electrodynamics. The text gives particular attention to the study of quantum systems. This study begins with a discussion of problems of quantum statistics with a detailed description of the basics of quantum mechanics along with the theory of measurement. An analysis of the asymptotic be

Estuary-ocean connectivity: fast physics, slow biology.

Science.gov (United States)

Raimonet, Mélanie; Cloern, James E

2017-06-01

Estuaries are connected to both land and ocean so their physical, chemical, and biological dynamics are influenced by climate patterns over watersheds and ocean basins. We explored climate-driven oceanic variability as a source of estuarine variability by comparing monthly time series of temperature and chlorophyll-a inside San Francisco Bay with those in adjacent shelf waters of the California Current System (CCS) that are strongly responsive to wind-driven upwelling. Monthly temperature fluctuations inside and outside the Bay were synchronous, but their correlations weakened with distance from the ocean. These results illustrate how variability of coastal water temperature (and associated properties such as nitrate and oxygen) propagates into estuaries through fast water exchanges that dissipate along the estuary. Unexpectedly, there was no correlation between monthly chlorophyll-a variability inside and outside the Bay. However, at the annual scale Bay chlorophyll-a was significantly correlated with the Spring Transition Index (STI) that sets biological production supporting fish recruitment in the CCS. Wind forcing of the CCS shifted in the late 1990s when the STI advanced 40 days. This shift was followed, with lags of 1-3 years, by 3- to 19-fold increased abundances of five ocean-produced demersal fish and crustaceans and 2.5-fold increase of summer chlorophyll-a in the Bay. These changes reflect a slow biological process of estuary-ocean connectivity operating through the immigration of fish and crustaceans that prey on bivalves, reduce their grazing pressure, and allow phytoplankton biomass to build. We identified clear signals of climate-mediated oceanic variability in this estuary and discovered that the response patterns vary with the process of connectivity and the timescale of ocean variability. This result has important implications for managing nutrient inputs to estuaries connected to upwelling systems, and for assessing their responses to changing

Nonlinear dimensionality reduction methods for synthetic biology biobricks' visualization.

Science.gov (United States)

Yang, Jiaoyun; Wang, Haipeng; Ding, Huitong; An, Ning; Alterovitz, Gil

2017-01-19

Visualizing data by dimensionality reduction is an important strategy in Bioinformatics, which could help to discover hidden data properties and detect data quality issues, e.g. data noise, inappropriately labeled data, etc. As crowdsourcing-based synthetic biology databases face similar data quality issues, we propose to visualize biobricks to tackle them. However, existing dimensionality reduction methods could not be directly applied on biobricks datasets. Hereby, we use normalized edit distance to enhance dimensionality reduction methods, including Isomap and Laplacian Eigenmaps. By extracting biobricks from synthetic biology database Registry of Standard Biological Parts, six combinations of various types of biobricks are tested. The visualization graphs illustrate discriminated biobricks and inappropriately labeled biobricks. Clustering algorithm K-means is adopted to quantify the reduction results. The average clustering accuracy for Isomap and Laplacian Eigenmaps are 0.857 and 0.844, respectively. Besides, Laplacian Eigenmaps is 5 times faster than Isomap, and its visualization graph is more concentrated to discriminate biobricks. By combining normalized edit distance with Isomap and Laplacian Eigenmaps, synthetic biology biobircks are successfully visualized in two dimensional space. Various types of biobricks could be discriminated and inappropriately labeled biobricks could be determined, which could help to assess crowdsourcing-based synthetic biology databases' quality, and make biobricks selection.

Shifting to structures in physics and biology: a prophylactic for promiscuous realism.

Science.gov (United States)

French, Steven

2011-06-01

Within the philosophy of science, the realism debate has been revitalised by the development of forms of structural realism. These urge a shift in focus from the object oriented ontologies that come and go through the history of science to the structures that remain through theory change. Such views have typically been elaborated in the context of theories of physics and are motivated by, first of all, the presence within such theories of mathematical equations that allow straightforward representation of the relevant structures; and secondly, the implications of such theories for the individuality and identity of putative objects. My aim in this paper is to explore the possibility of extending such views to biological theories. An obvious concern is that within the context of the latter it is typically insisted that we cannot find the kinds of highly mathematised structures that structural realism can point to in physics. I shall indicate how the model-theoretic approach to theories might help allay such concerns. Furthermore, issues of identity and individuality also arise within biology. Thus Dupré has recently noted that there exists a 'General Problem of Biological Individuality' which relates to the issue of how one divides 'massively integrated and interconnected' systems into discrete components. In response Dupré advocates a form of 'Promiscuous Realism' that holds, for example, that there is no unique way of dividing the phylogenetic tree into kinds. Instead I shall urge serious consideration of those aspects of the work of Dupré and others that lean towards a structuralist interpretation. By doing so I hope to suggest possible ways in which a structuralist stance might be extended to biology. Copyright © 2010 Elsevier Ltd. All rights reserved.

Dynamic light scattering with applications to chemistry, biology, and physics

CERN Document Server

Berne, Bruce J

2000-01-01

Lasers play an increasingly important role in a variety of detection techniques, making inelastic light scattering a tool of growing value in the investigation of dynamic and structural problems in chemistry, biology, and physics. Until the initial publication of this work, however, no monograph treated the principles behind current developments in the field.This volume presents a comprehensive introduction to the principles underlying laser light scattering, focusing on the time dependence of fluctuations in fluid systems; it also serves as an introduction to the theory of time correlation f

Biological detector and method

Science.gov (United States)

Sillerud, Laurel; Alam, Todd M; McDowell, Andrew F

2013-02-26

A biological detector includes a conduit for receiving a fluid containing one or more magnetic nanoparticle-labeled, biological objects to be detected and one or more permanent magnets or electromagnet for establishing a low magnetic field in which the conduit is disposed. A microcoil is disposed proximate the conduit for energization at a frequency that permits detection by NMR spectroscopy of whether the one or more magnetically-labeled biological objects is/are present in the fluid.

Living matter—nexus of physics and biology in the 21st century

Science.gov (United States)

Gardel, Margaret L.

2012-01-01

Cells are made up of complex assemblies of cytoskeletal proteins that facilitate force transmission from the molecular to cellular scale to regulate cell shape and force generation. The “living matter” formed by the cytoskeleton facilitates versatile and robust behaviors of cells, including their migration, adhesion, division, and morphology, that ultimately determine tissue architecture and mechanics. Elucidating the underlying physical principles of such living matter provides great opportunities in both biology and physics. For physicists, the cytoskeleton provides an exceptional toolbox to study materials far from equilibrium. For biologists, these studies will provide new understanding of how molecular-scale processes determine cell morphological changes. PMID:23112229

Numerical simulations of flying and swimming of biological systems with the viscous vortex particle method

Science.gov (United States)

Eldredge, Jeff

2005-11-01

Many biological mechanisms of locomotion involve the interaction of a fluid with a deformable surface undergoing large unsteady motion. Analysis of such problems poses a significant challenge to conventional grid-based computational approaches. Particularly in the moderate Reynolds number regime where many insects and fish function, viscous and inertial processes are both important, and vorticity serves a crucial role. In this work, the viscous vortex particle method is shown to provide an efficient, intuitive simulation approach for investigation of these biological systems. In contrast with a grid-based approach, the method solves the Navier--Stokes equations by tracking computational particles that carry smooth blobs of vorticity and exchange strength with one another to account for viscous diffusion. Thus, computational resources are focused on the physically relevant features of the flow, and there is no need for artificial boundary conditions. Building from previously-developed techniques for the creation of vorticity to enforce no-throughflow and no-slip conditions, the present method is extended to problems of coupled fluid--body dynamics by enforcement of global conservation of momenta. The application to several two-dimensional model problems is demonstrated, including single and multiple flapping wings and free swimming of a three-linkage fish.

Synthetic Methods and Exploring Biological Potential of Various Substituted Quinoxalin-2-one Derivatives

OpenAIRE

Mohammad Asif

2016-01-01

Substituted quinoxaline have considerable interest in chemistry, biology and pharmacology. Quinoxaline derivatives are capable with variety of biological activities and possess different biological activities, of which the most potent are anti-microbial, analgesic and anti-inflammatory activities. It facilitated the researchers to develop various methods for their synthesis and their applications. In this review represented different methods of synthesis, reactivity and various biological act...

Vertical stratification of physical, chemical and biological components in two saline lakes Shira and Shunet (South Siberia, Russia)

NARCIS (Netherlands)

Degermendzhy, A.G.; Zadereev, E.S.; Rogozin, D.Y.; Prokopkin, I.; Barkhatov, Y.V.; Tolomeev, A.; Khromechek, E.B.; Janse, J.H.; Mooij, W.M.; Gulati, R.D.

2010-01-01

A feature of meromictic lakes is that several physicochemical and biological gradients affect the vertical distribution of different organisms. The vertical stratification of physical, chemical and biological components in saline, fishless meromictic lakes Shira and Shunet (Siberia, Russia) is quite

Progeny Clustering: A Method to Identify Biological Phenotypes

Science.gov (United States)

Hu, Chenyue W.; Kornblau, Steven M.; Slater, John H.; Qutub, Amina A.

2015-01-01

Estimating the optimal number of clusters is a major challenge in applying cluster analysis to any type of dataset, especially to biomedical datasets, which are high-dimensional and complex. Here, we introduce an improved method, Progeny Clustering, which is stability-based and exceptionally efficient in computing, to find the ideal number of clusters. The algorithm employs a novel Progeny Sampling method to reconstruct cluster identity, a co-occurrence probability matrix to assess the clustering stability, and a set of reference datasets to overcome inherent biases in the algorithm and data space. Our method was shown successful and robust when applied to two synthetic datasets (datasets of two-dimensions and ten-dimensions containing eight dimensions of pure noise), two standard biological datasets (the Iris dataset and Rat CNS dataset) and two biological datasets (a cell phenotype dataset and an acute myeloid leukemia (AML) reverse phase protein array (RPPA) dataset). Progeny Clustering outperformed some popular clustering evaluation methods in the ten-dimensional synthetic dataset as well as in the cell phenotype dataset, and it was the only method that successfully discovered clinically meaningful patient groupings in the AML RPPA dataset. PMID:26267476

Evaluation of conformal radiotherapy techniques through physics and biologic criteria

International Nuclear Information System (INIS)

Bloch, Jonatas Carrero

2012-01-01

In the fight against cancer, different irradiation techniques have been developed based on technological advances and aiming to optimize the elimination of tumor cells with the lowest damage to healthy tissues. The radiotherapy planning goal is to establish irradiation technical parameters in order to achieve the prescribed dose distribution over the treatment volumes. While dose prescription is based on radiosensitivity of the irradiated tissues, the physical calculations on treatment planning take into account dosimetric parameters related to the radiation beam and the physical characteristics of the irradiated tissues. To incorporate tissue's radiosensitivity into radiotherapy planning calculations can help particularize treatments and establish criteria to compare and elect radiation techniques, contributing to the tumor control and the success of the treatment. Accordingly, biological models of cellular response to radiation have to be well established. This work aimed to study the applicability of using biological models in radiotherapy planning calculations to aid evaluating radiotherapy techniques. Tumor control probability (TCP) was studied for two formulations of the linear-quadratic model, with and without repopulation, as a function of planning parameters, as dose per fraction, and of radiobiological parameters, as the α/β ratio. Besides, the usage of biological criteria to compare radiotherapy techniques was tested using a prostate planning simulated with Monte Carlo code PENELOPE. Afterwards, prostate planning for five patients from the Hospital das Clinicas da Faculdade de Medicina de Ribeirao Preto, USP, using three different techniques were compared using the tumor control probability. In that order, dose matrices from the XiO treatment planning system were converted to TCP distributions and TCP-volume histograms. The studies performed allow the conclusions that radiobiological parameters can significantly influence tumor control

[The assessment of biological maturation for talent selection - which method can be used?].

Science.gov (United States)

Müller, L; Müller, E; Hildebrandt, C; Kapelari, K; Raschner, C

2015-03-01

The biological maturity status plays an important role in sports, since it influences the performance level and the talent selection in various types of sport. More mature athletes are favorably selected for regional and national squads. Therefore, the biological maturity status should be considered during the talent selection process. In this context, the relative age effect (RAE), which exists when the relative age quarter distribution of selected sports groups shows a biased distribution with an over-representation of athletes born in the first months after the specific cut-off-date for the competition categories, represents another problem in the talent development. From an ethical point of view, discrimination of young talented kids does exist: the relatively younger athletes have little to no chance of reaching the elite level, despite their talents and efforts. The causal mechanisms behind the RAE are still unclear and have to be assessed. In this context, the biological maturation seems to be a possible influential factor for the existence of a RAE in sport, which has to be examined. Several methods for estimating the biological maturity status exist; however, they are often expensive and not practicable. Consequently, the aim of the present study was to assess the concordance of a simple, yet accurate method of estimating biological maturation (prediction equation of age at peak height velocity, APHV) of Mirwald and co-workers, and the gold standard method of estimating skeletal age (SA, the x-ray of the left wrist). In total, 75 Austrian students (40♂, 35♀) aged 10 - 13 years, were examined. Thirty of the participants (17♂, 13♀) were students of a well-known Austrian ski boarding school, and 45 (23♂, 22♀) of a non-sportive secondary modern school of the same region. The participants included in the study had not experienced a rupture of the carpal bones of the left wrist. Parents and participants were informed of the study aims

Evaluation of the Teaching Methods Used in Secondary School Biology Lessons

Directory of Open Access Journals (Sweden)

Porozovs Juris

2015-06-01

Full Text Available The teacher’s skills in conducting the lesson and choice of teaching methods play an essential role in creating students’ interest in biology. The aim of the research was to study the opinion of secondary school students and biology teachers regarding the most successful teaching methods used in biology lessons and viable options to make biology lessons more interesting. The research comprised polling students and biology teachers from several schools, namely: 2 secondary schools in Jelgava, 2 in Riga and 1 in Vecumnieki. The responses revealed that 58% of students find biology lessons interesting. 56% of students indicated that their ability to focus attention during biology lessons depends on the task presented to them. Most of all they prefer watching the teacher’s presentations, listening to their teacher telling about the actual topic as well as performing laboratory work and group-work. Many students like participating in discussions, whereas a far smaller number would do various exercises, individual tasks, fill out worksheets or complete projects. Least of all students wish to work with the textbook. The methods most frequently applied by teachers are as follows: lecture, explanation, demonstration, and discussion. Teachers believe that their students prefer laboratory work and discussions as well as listening to their teacher and watching presentations or films. They also indicate at the necessity to link theory with practice and to involve information technologies. While teaching their subject biology teachers try to establish relationship between theory and real life in order to develop their students’ interest in natural processes.

Using the Scientific Method to Motivate Biology Students to Study Precalculus

Science.gov (United States)

Fulton, James P.; Sabatino, Linda

2008-01-01

During the last two years we have developed a precalculus course customized around biology by using the scientific method as a framework to engage and motivate biology students. Historically, the precalculus and calculus courses required for the Suffolk County Community College biology curriculum were designed using examples from the physical…

Radiation damage and repair in cells and cell components. Part 2. Physical radiations and biological significance. Final report

International Nuclear Information System (INIS)

Fluke, D.J.

1984-08-01

The report comprises a teaching text, encompassing all physical radiations likely to be of biological interest, and the relevant biological effects and their significance. Topics include human radiobiology, delayed effects, radiation absorption in organisms, aqueous radiation chemistry, cell radiobiology, mutagenesis, and photobiology

Biological and physical controls in the Southern Ocean on past millennial-scale atmospheric CO2 changes.

Science.gov (United States)

Gottschalk, Julia; Skinner, Luke C; Lippold, Jörg; Vogel, Hendrik; Frank, Norbert; Jaccard, Samuel L; Waelbroeck, Claire

2016-05-17

Millennial-scale climate changes during the last glacial period and deglaciation were accompanied by rapid changes in atmospheric CO2 that remain unexplained. While the role of the Southern Ocean as a 'control valve' on ocean-atmosphere CO2 exchange has been emphasized, the exact nature of this role, in particular the relative contributions of physical (for example, ocean dynamics and air-sea gas exchange) versus biological processes (for example, export productivity), remains poorly constrained. Here we combine reconstructions of bottom-water [O2], export production and (14)C ventilation ages in the sub-Antarctic Atlantic, and show that atmospheric CO2 pulses during the last glacial- and deglacial periods were consistently accompanied by decreases in the biological export of carbon and increases in deep-ocean ventilation via southern-sourced water masses. These findings demonstrate how the Southern Ocean's 'organic carbon pump' has exerted a tight control on atmospheric CO2, and thus global climate, specifically via a synergy of both physical and biological processes.

Meta-cognition about biological sex and gender-stereotypic physical appearance: consequences for the assessment of leadership competence.

Science.gov (United States)

Sczesny, Sabine; Kühnen, Ulrich

2004-01-01

Previous findings are inconsistent with regard to whether men are judged as being more or less competent leaders than women. However, masculine-relative to feminine-looking persons seem to be judged consistently as more competent leaders. Can this different impact of biological sex and physical appearance be due to the disparate availability of meta-cognitive knowledge about both sources? The results of Study 1 indicated that individuals possess meta-cognitive knowledge about a possible biasing influence of persons' biological sex, but not for their physical appearance. In Study 2, participants judged the leadership competence of a male versus female stimulus person with either masculine or feminine physical appearance. In addition, the available cognitive capacity was manipulated. When high capacity was available, participants corrected for the influence of stimulus persons' sex, but they fell prey to this influence under cognitive load. However, the effect of physical appearance was not moderated by cognitive capacity.

Summer nitrogenous nutrient transport and its fate in the Taiwan Strait: A coupled physical-biological modeling approach

Science.gov (United States)

Wang, Jia; Hong, Huasheng; Jiang, Yuwu; Chai, Fei; Yan, Xiao-Hai

2013-09-01

In order to understand the fate of nutrients in the Taiwan Strait during summer, we built a coupled physical-biological numerical ocean model, which can capture the basic hydrographic and biological features within the strait. The nutrient that we chose to model is dissolved inorganic nitrogen (DIN). The model includes individual reservoirs for nitrate (NO3) and ammonium (NH4). Both the observational evidence and model results show that NO3 in the strait originates primarily from the upwelling subsurface water in the northern South China Sea (SCS) that enters the strait via the eastern and western routes separated by the Taiwan Bank. The coupled physical and biological effects on the NO3 transport at these two routes are highlighted in the study. For the western route, the shallow topography and the coastal upwelling intensify the biological uptake of NO3 in the whole water column. Consequently, the nitrogenous contribution by this route is mainly in form of the particulate organic nitrogen (PON). In contrast, NO3 is transported conservatively below the nitricline at the deep eastern route, contributing the whole NO3 supply in the TWS. The model estimates the fluxes of DIN and PON into the TWS, from the northern SCS, are 1.8 and 4 kmol s-1, respectively. Over half (˜1 kmol s-1) of the DIN is synthesized into PON by the phytoplankton in the strait. Overall, this study estimates the physical and biological effects on the nutrient transport in the TWS during summer.

A comparative analysis on computational methods for fitting an ERGM to biological network data

Directory of Open Access Journals (Sweden)

Sudipta Saha

2015-03-01

Full Text Available Exponential random graph models (ERGM based on graph theory are useful in studying global biological network structure using its local properties. However, computational methods for fitting such models are sensitive to the type, structure and the number of the local features of a network under study. In this paper, we compared computational methods for fitting an ERGM with local features of different types and structures. Two commonly used methods, such as the Markov Chain Monte Carlo Maximum Likelihood Estimation and the Maximum Pseudo Likelihood Estimation are considered for estimating the coefficients of network attributes. We compared the estimates of observed network to our random simulated network using both methods under ERGM. The motivation was to ascertain the extent to which an observed network would deviate from a randomly simulated network if the physical numbers of attributes were approximately same. Cut-off points of some common attributes of interest for different order of nodes were determined through simulations. We implemented our method to a known regulatory network database of Escherichia coli (E. coli.

Materials of 4. international meeting on pulse investigations in physics, chemistry and biology. PULS'94

International Nuclear Information System (INIS)

1994-01-01

4. International Meeting on Pulse Investigations in Physics, Chemistry and Biology, PULS'94 has been organized in honor of Professor Jerzy Kroh, the precursor of radiation chemistry in Poland. The meeting has been divided into three sessions: the historical session (H) with four review lectures, lecture session (L) collected 23 papers and poster session (P) with 39 posters. The fundamental studies on early stages of radiolysis have been presented for different systems being irradiated. The pulse radiolysis and flash photolysis methods has been predominantly used in reported experimental works. The reaction of intermediate products of radiolysis and photolysis such a trapped and solvated electrons, ions and radicals has been extensively studied. The reaction mechanisms and kinetics have been also discussed

Advanced analysis methods in particle physics

Energy Technology Data Exchange (ETDEWEB)

Bhat, Pushpalatha C.; /Fermilab

2010-10-01

Each generation of high energy physics experiments is grander in scale than the previous - more powerful, more complex and more demanding in terms of data handling and analysis. The spectacular performance of the Tevatron and the beginning of operations of the Large Hadron Collider, have placed us at the threshold of a new era in particle physics. The discovery of the Higgs boson or another agent of electroweak symmetry breaking and evidence of new physics may be just around the corner. The greatest challenge in these pursuits is to extract the extremely rare signals, if any, from huge backgrounds arising from known physics processes. The use of advanced analysis techniques is crucial in achieving this goal. In this review, I discuss the concepts of optimal analysis, some important advanced analysis methods and a few examples. The judicious use of these advanced methods should enable new discoveries and produce results with better precision, robustness and clarity.

Teleology in biology, chemistry and physics education: what primary teachers should know

Directory of Open Access Journals (Sweden)

KOSTAS KAMPOURAKIS

2007-01-01

Full Text Available Recent research in cognitive psychology suggests that children develop intuitions that may clash with what is accepted by scientists, thus making certain scientific concepts difficult to understand. Children possess intuitions about design and purpose that make them provide teleological explanations to many different sorts of tasks. One possible explanation for the origin of the bias to view objects as made for something derives from an early sensitivity to intentional agents and to their behavior as intentional object users and object makers. What is important is that teleological explanations may not be exclusively restricted in biological phenomena, as commonly assumed. Consequently, primary school teachers should take that into account when teaching biology, chemistry or physics concepts and try to refrain from enforcing students’ teleological intuitions.

Comparison in the determination of absorbed dose by biological and physical methods to patients in treatment of cardiac intervention; Comparacion en la determinacion de dosis absorbida por metodos biologicos y fisicos a pacientes en tratamiento de intervencionismo cardiaco

Energy Technology Data Exchange (ETDEWEB)

Guerrero C, C.; Arceo M, C., E-mail: citlali.guerrero@inin.gob.mx [ININ, Departamento de Biologia, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2014-10-15

The use of less invasive procedures, lower risk and quick recovery as cardiac intervention have proven to be an efficient alternative to reestablish the correct bloodstream of the patient. In this case the patient is subjected to values of absorbed dose above to which is subjected in a study with X-rays for medical diagnosis, and this can cause radiation injuries to the skin. The target organ, in this case can be exposed to doses of 2 Gy above. Different methods to estimate the dose were use, physical by Radiochromic film, as biological by dicentric analysis. Both methods provided additional information demonstrating thus the risk in the target organ and the patient. The most reliable biological indicator of exposure to ionizing radiation is the study of chromosomal aberrations, specifically dicentric in human lymphocytes. This test allowed establishing the exposure dose depending of the damage. (Author)

Physical Activity and Telomere Biology: Exploring the Link with Aging-Related Disease Prevention

Directory of Open Access Journals (Sweden)

Andrew T. Ludlow

2011-01-01

Full Text Available Physical activity is associated with reduced risk of several age-related diseases as well as with increased longevity in both rodents and humans. Though these associations are well established, evidence of the molecular and cellular factors associated with reduced disease risk and increased longevity resulting from physical activity is sparse. A long-standing hypothesis of aging is the telomere hypothesis: as a cell divides, telomeres shorten resulting eventually in replicative senescence and an aged phenotype. Several reports have recently associated telomeres and telomere-related proteins to diseases associated with physical inactivity and aging including cardiovascular disease, insulin resistance, and hypertension. Interestingly several reports have also shown that longer telomeres are associated with higher physical activity levels, indicating a potential mechanistic link between physical activity, reduced age-related disease risk, and longevity. The primary purpose of this review is to discuss the potential importance of physical activity in telomere biology in the context of inactivity- and age-related diseases. A secondary purpose is to explore potential mechanisms and important avenues for future research in the field of telomeres and diseases associated with physical inactivity and aging.

Proteins Encoded in Genomic Regions Associated with Immune-Mediated Disease Physically Interact and Suggest Underlying Biology

DEFF Research Database (Denmark)

Rossin, Elizabeth J.; Hansen, Kasper Lage; Raychaudhuri, Soumya

2011-01-01

Genome-wide association studies (GWAS) have defined over 150 genomic regions unequivocally containing variation predisposing to immune-mediated disease. Inferring disease biology from these observations, however, hinges on our ability to discover the molecular processes being perturbed by these r......Genome-wide association studies (GWAS) have defined over 150 genomic regions unequivocally containing variation predisposing to immune-mediated disease. Inferring disease biology from these observations, however, hinges on our ability to discover the molecular processes being perturbed...... in rheumatoid arthritis (RA) and Crohn's disease (CD) GWAS, we build protein-protein interaction (PPI) networks for genes within associated loci and find abundant physical interactions between protein products of associated genes. We apply multiple permutation approaches to show that these networks are more...... that the RA and CD networks have predictive power by demonstrating that proteins in these networks, not encoded in the confirmed list of disease associated loci, are significantly enriched for association to the phenotypes in question in extended GWAS analysis. Finally, we test our method in 3 non...

Biologically Based Methods for Control of Fumonisin-Producing Fusarium Species and Reduction of the Fumonisins

Science.gov (United States)

Alberts, Johanna F.; van Zyl, Willem H.; Gelderblom, Wentzel C. A.

2016-01-01

selected biologically based treatments, mild chemical and physical treatments could reduce fumonisin contamination effectively. In rural subsistence farming communities, simple, practical, and culturally acceptable hand-sorting, maize kernel washing, and dehulling intervention methods proved to be effective as a last line of defense for reducing fumonisin exposure. Biologically based methods for control of fumonisin-producing Fusarium spp. and decontamination of the fumonisins could have potential commercial application, while simple and practical intervention strategies could also impact positively on food safety and security, especially in rural populations reliant on maize as a dietary staple. PMID:27199904

Biologically Based Methods for Control of Fumonisin-Producing Fusarium Species and Reduction of the Fumonisins.

Science.gov (United States)

Alberts, Johanna F; van Zyl, Willem H; Gelderblom, Wentzel C A

2016-01-01

selected biologically based treatments, mild chemical and physical treatments could reduce fumonisin contamination effectively. In rural subsistence farming communities, simple, practical, and culturally acceptable hand-sorting, maize kernel washing, and dehulling intervention methods proved to be effective as a last line of defense for reducing fumonisin exposure. Biologically based methods for control of fumonisin-producing Fusarium spp. and decontamination of the fumonisins could have potential commercial application, while simple and practical intervention strategies could also impact positively on food safety and security, especially in rural populations reliant on maize as a dietary staple.

Biologically Based Methods for Control of Fumonisin-producing Fusarium species and Reduction of the Fumonisins

Directory of Open Access Journals (Sweden)

Johanna Francina Alberts

2016-04-01

, together with selected biologically based treatments, mild chemical and physical treatments could reduce fumonisin contamination effectively. In rural subsistence farming communities, simple, practical and culturally acceptable hand-sorting, maize kernel washing and dehulling intervention methods proved to be effective as a last line of defence for reducing fumonisin exposure. Biologically based methods for control of fumonisin-producing Fusarium spp. and decontamination of the fumonisins could have potential commercial application, while simple and practical intervention strategies could also impact positively on food safety and security, especially in rural populations reliant on maize as a dietary staple.

Courses in Modern Physics for Non-science Majors, Future Science Teachers, and Biology Students

Science.gov (United States)

Zollman, Dean

2001-03-01

For the past 15 years Kansas State University has offered a course in modern physics for students who are not majoring in physics. This course carries a prerequisite of one physics course so that the students have a basic introduction in classical topics. The majors of students range from liberal arts to engineering. Future secondary science teachers whose first area of teaching is not physics can use the course as part of their study of science. The course has evolved from a lecture format to one which is highly interactive and uses a combination of hands-on activities, tutorials and visualizations, particularly the Visual Quantum Mechanics materials. Another course encourages biology students to continue their physics learning beyond the introductory course. Modern Miracle Medical Machines introduces the basic physics which underlie diagnosis techniques such as MRI and PET and laser surgical techniques. Additional information is available at http://www.phys.ksu.edu/perg/

Proteins Encoded in Genomic Regions Associated with Immune-Mediated Disease Physically Interact and Suggest Underlying Biology

Science.gov (United States)

Rossin, Elizabeth J.; Lage, Kasper; Raychaudhuri, Soumya; Xavier, Ramnik J.; Tatar, Diana; Benita, Yair

2011-01-01

Genome-wide association studies (GWAS) have defined over 150 genomic regions unequivocally containing variation predisposing to immune-mediated disease. Inferring disease biology from these observations, however, hinges on our ability to discover the molecular processes being perturbed by these risk variants. It has previously been observed that different genes harboring causal mutations for the same Mendelian disease often physically interact. We sought to evaluate the degree to which this is true of genes within strongly associated loci in complex disease. Using sets of loci defined in rheumatoid arthritis (RA) and Crohn's disease (CD) GWAS, we build protein–protein interaction (PPI) networks for genes within associated loci and find abundant physical interactions between protein products of associated genes. We apply multiple permutation approaches to show that these networks are more densely connected than chance expectation. To confirm biological relevance, we show that the components of the networks tend to be expressed in similar tissues relevant to the phenotypes in question, suggesting the network indicates common underlying processes perturbed by risk loci. Furthermore, we show that the RA and CD networks have predictive power by demonstrating that proteins in these networks, not encoded in the confirmed list of disease associated loci, are significantly enriched for association to the phenotypes in question in extended GWAS analysis. Finally, we test our method in 3 non-immune traits to assess its applicability to complex traits in general. We find that genes in loci associated to height and lipid levels assemble into significantly connected networks but did not detect excess connectivity among Type 2 Diabetes (T2D) loci beyond chance. Taken together, our results constitute evidence that, for many of the complex diseases studied here, common genetic associations implicate regions encoding proteins that physically interact in a preferential manner, in

Advantages and challenges of using physics curricula as a model for reforming an undergraduate biology course.

Science.gov (United States)

Donovan, D A; Atkins, L J; Salter, I Y; Gallagher, D J; Kratz, R F; Rousseau, J V; Nelson, G D

2013-06-01

We report on the development of a life sciences curriculum, targeted to undergraduate students, which was modeled after a commercially available physics curriculum and based on aspects of how people learn. Our paper describes the collaborative development process and necessary modifications required to apply a physics pedagogical model in a life sciences context. While some approaches were easily adapted, others provided significant challenges. Among these challenges were: representations of energy, introducing definitions, the placement of Scientists' Ideas, and the replicability of data. In modifying the curriculum to address these challenges, we have come to see them as speaking to deeper differences between the disciplines, namely that introductory physics--for example, Newton's laws, magnetism, light--is a science of pairwise interaction, while introductory biology--for example, photosynthesis, evolution, cycling of matter in ecosystems--is a science of linked processes, and we suggest that this is how the two disciplines are presented in introductory classes. We illustrate this tension through an analysis of our adaptations of the physics curriculum for instruction on the cycling of matter and energy; we show that modifications of the physics curriculum to address the biological framework promotes strong gains in student understanding of these topics, as evidenced by analysis of student work.

Open Water Processes of the San Francisco Estuary: From Physical Forcing to Biological Responses

Directory of Open Access Journals (Sweden)

Wim Kimmerer

2004-02-01

Full Text Available This paper reviews the current state of knowledge of the open waters of the San Francisco Estuary. This estuary is well known for the extent to which it has been altered through loss of wetlands, changes in hydrography, and the introduction of chemical and biological contaminants. It is also one of the most studied estuaries in the world, with much of the recent research effort aimed at supporting restoration efforts. In this review I emphasize the conceptual foundations for our current understanding of estuarine dynamics, particularly those aspects relevant to restoration. Several themes run throughout this paper. First is the critical role physical dynamics play in setting the stage for chemical and biological responses. Physical forcing by the tides and by variation in freshwater input combine to control the movement of the salinity field, and to establish stratification, mixing, and dilution patterns throughout the estuary. Many aspects of estuarine dynamics respond to interannual variation in freshwater flow; in particular, abundance of several estuarine-dependent species of fish and shrimp varies positively with flow, although the mechanisms behind these relationships are largely unknown. The second theme is the importance of time scales in determining the degree of interaction between dynamic processes. Physical effects tend to dominate when they operate at shorter time scales than biological processes; when the two time scales are similar, important interactions can arise between physical and biological variability. These interactions can be seen, for example, in the response of phytoplankton blooms, with characteristic time scales of days, to stratification events occurring during neap tides. The third theme is the key role of introduced species in all estuarine habitats; particularly noteworthy are introduced waterweeds and fishes in the tidal freshwater reaches of the estuary, and introduced clams there and in brackish water. The

Geometric Methods in Physics XXXV

CERN Document Server

Odzijewicz, Anatol; Previato, Emma

2018-01-01

This book features a selection of articles based on the XXXV Białowieża Workshop on Geometric Methods in Physics, 2016. The series of Białowieża workshops, attended by a community of experts at the crossroads of mathematics and physics, is a major annual event in the field. The works in this book, based on presentations given at the workshop, are previously unpublished, at the cutting edge of current research, typically grounded in geometry and analysis, and with applications to classical and quantum physics. In 2016 the special session "Integrability and Geometry" in particular attracted pioneers and leading specialists in the field. Traditionally, the Białowieża Workshop is followed by a School on Geometry and Physics, for advanced graduate students and early-career researchers, and the book also includes extended abstracts of the lecture series.

Interdisciplinary didactics alternative from the biological sciences with the professional practice disciplines in physical culture career of Pinar del Río

Directory of Open Access Journals (Sweden)

Idelfonso Javiqué-Leal

2013-12-01

Full Text Available When we applied alternatives and working algorism to put into practice the knowledge in the different subjects during the instructive- learning process it is important the exclusion of all empirical level in the teaching contents. The Biological science in essence constitutes a subject in the specific basic formation aimed to the integration of the future professional in the physical Culture majoring which has an important influence on the rest of the subjects that are part of the curriculum .In the present work we can show the results of one of the tasks corresponding to the research project related to the didactic changes in the Biological sciences subject, derived from the difficulties found in the teaching process. The authors give an approximation of how to deal with the different components in the teaching leaning- process with concrete results on the base theoretical and empiric methods. They give a work alternative to establish basic concepts with the didactic of the Physical education and sport showing advance evidences in the didactic order giving a high level of work in this subject.

FEATURES OF METHODS OF FUTURE PHYSICAL CULTURE TEACHERS’ TRAINING FOR PHYSICAL EDUCATION OF HIGH SCHOOL STUDENTS

Directory of Open Access Journals (Sweden)

Петро Джуринський

2014-12-01

Full Text Available The paper presents the methodical approaches and recommendations on implementation of methods of future Physical Culture teachers to physical education of high school students into study process at a higher educational institution. The role of the approbated study discipline “Theory and methods of physical education at high school” has been determined in this research. It has also been defined, that future Physical Culture teacher’s training for physical education of high school students is a system of organizational and educational measures, ensuring the formation of future teacher’s professional knowledge and skills. The article presents the defined tasks, criteria, tools, forms, pedagogical conditions and stages of students’ training for teaching classes of Physical Education to high school students. Approbation of methodical approaches to future Physical Culture teachers’ training for physical education of high school students demonstrated their efficacy

Life sciences: Nuclear medicine, radiation biology, medical physics, 1980-1994. International Atomic Energy Agency Publications

International Nuclear Information System (INIS)

1994-11-01

The catalogue lists all sales publications of the IAEA dealing with Life Sciences issued during the period 1980-1994. The publications are grouped in the following chapters: Nuclear Medicine (including Radiopharmaceuticals), Radiation Biology and Medical Physics (including Dosimetry)

Microgravity Fluids for Biology, Workshop

Science.gov (United States)

Griffin, DeVon; Kohl, Fred; Massa, Gioia D.; Motil, Brian; Parsons-Wingerter, Patricia; Quincy, Charles; Sato, Kevin; Singh, Bhim; Smith, Jeffrey D.; Wheeler, Raymond M.

2013-01-01

Microgravity Fluids for Biology represents an intersection of biology and fluid physics that present exciting research challenges to the Space Life and Physical Sciences Division. Solving and managing the transport processes and fluid mechanics in physiological and biological systems and processes are essential for future space exploration and colonization of space by humans. Adequate understanding of the underlying fluid physics and transport mechanisms will provide new, necessary insights and technologies for analyzing and designing biological systems critical to NASAs mission. To enable this mission, the fluid physics discipline needs to work to enhance the understanding of the influence of gravity on the scales and types of fluids (i.e., non-Newtonian) important to biology and life sciences. In turn, biomimetic, bio-inspired and synthetic biology applications based on physiology and biology can enrich the fluid mechanics and transport phenomena capabilities of the microgravity fluid physics community.

Nitrogen Retention in Coastal Marine Sediments—a Field Study of the Relative Importance of Biological and Physical Removal in a Danish Estuary

DEFF Research Database (Denmark)

Laurentius Nielsen, Søren; Risgaard-Petersen, Nils; Banta, Gary

2017-01-01

The aim of this study was to elucidate the relative importance of physical versus biological loss processes for the removal of microphytobenthic (MPB) bound nitrogen in a coastal environment at different times of the year via a dual isotope labeling technique. We used 51Cr, binding to inorganic...... were able to discern the relative importance of physical and biological processes. The isotope marking was supplemented with measurements of sediment chlorophyll biomass and oxygen fluxes, allowing us to evaluate MPB biomass as well as primary production vs. respiration in the sediment. In spring...... was physically dominated due to low MPB biomasses and activity combined with a significant storm event. Our data support the hypothesis that the relative balance between physical and biological processes in determining retention and removal of MPB-bound nitrogen changes seasonally....

The quest for a new modelling framework in mathematical biology. Comment on "On the interplay between mathematics and biology: Hallmarks towards a new systems biology" by N. Bellomo et al.

Science.gov (United States)

Eftimie, Raluca

2015-03-01

One of the main unsolved problems of modern physics is finding a "theory of everything" - a theory that can explain, with the help of mathematics, all physical aspects of the universe. While the laws of physics could explain some aspects of the biology of living systems (e.g., the phenomenological interpretation of movement of cells and animals), there are other aspects specific to biology that cannot be captured by physics models. For example, it is generally accepted that the evolution of a cell-based system is influenced by the activation state of cells (e.g., only activated and functional immune cells can fight diseases); on the other hand, the evolution of an animal-based system can be influenced by the psychological state (e.g., distress) of animals. Therefore, the last 10-20 years have seen also a quest for a "theory of everything"-approach extended to biology, with researchers trying to propose mathematical modelling frameworks that can explain various biological phenomena ranging from ecology to developmental biology and medicine [1,2,6]. The basic idea behind this approach can be found in a few reviews on ecology and cell biology [6,7,9-11], where researchers suggested that due to the parallel between the micro-scale dynamics and the emerging macro-scale phenomena in both cell biology and in ecology, many mathematical methods used for ecological processes could be adapted to cancer modelling [7,9] or to modelling in immunology [11]. However, this approach generally involved the use of different models to describe different biological aspects (e.g., models for cell and animal movement, models for competition between cells or animals, etc.).

Suitability of Gray Water for Hydroponic Crop Production Following Biological and Physical Chemical and Biological Subsystems

Science.gov (United States)

Bubenheim, David L.; Harper, Lynn D.; Wignarajah, Kanapathipillai; Greene, Catherine

1994-01-01

The water present in waste streams from a human habitat must be recycled in Controlled Ecological Life Support Systems (CELSS) to limit resupply needs and attain self-sufficiency. Plants play an important role in providing food, regenerating air, and producing purified water via transpiration. However, we have shown that the surfactants present in hygiene waste water have acute toxic effects on plant growth (Bubenheim et al. 1994; Greene et al., 1994). These phytotoxic affects can be mitigated by allowing the microbial population on the root surface to degrade the surfactant, however, a significant suppression (several days) in crop performance is experienced prior to reaching sub-toxic surfactant levels and plant recovery. An effective alternative is to stabilize the microbial population responsible for degradation of the surfactant on an aerobic bioreactor and process the waste water prior to utilization in the hydroponic solution (Wisniewski and Bubenheim, 1993). A sensitive bioassay indicates that the surfactant phytotoxicity is suppressed by more than 90% within 5 hours of introduction of the gray water to the bioreactor; processing for more than 12 hours degrades more than 99% of the phytotoxin. Vapor Compression Distillation (VCD) is a physical / chemical method for water purification which employees sequential distillation steps to separate water from solids and to volatilize contaminants. The solids from the waste water are concentrated in a brine and the pure product water (70 - 90% of the total waste water volume depending on operating conditions) retains non of the phytotoxic effects. Results of the bioassay were used to guide evaluations of the suitability of recovered gray water following biological and VCD processing for hydroponic lettuce production in controlled environments. Lettuce crops were grown for 28 days with 100% of the input water supplied with recovered water from the biological processor or VCD. When compared with the growth of plants

Disentangling physical and biological drivers of phytoplankton dynamics in a coastal system.

Science.gov (United States)

Cianelli, Daniela; D'Alelio, Domenico; Uttieri, Marco; Sarno, Diana; Zingone, Adriana; Zambianchi, Enrico; d'Alcalà, Maurizio Ribera

2017-11-20

This proof-of-concept study integrates the surface currents measured by high-frequency coastal radars with plankton time-series data collected at a fixed sampling point from the Mediterranean Sea (MareChiara Long Term Ecological Research site in the Gulf of Naples) to characterize the spatial origin of phytoplankton assemblages and to scrutinize the processes ruling their dynamics. The phytoplankton community generally originated from the coastal waters whereby species succession was mainly regulated by biological factors (life-cycle processes, species-specific physiological performances and inter-specific interactions). Physical factors, e.g. the alternation between coastal and offshore waters and the horizontal mixing, were also important drivers of phytoplankton dynamics promoting diversity maintenance by i) advecting species from offshore and ii) diluting the resident coastal community so as to dampen resource stripping by dominant species and thereby increase the numerical importance of rarer species. Our observations highlight the resilience of coastal communities, which may favour their persistence over time and the prevalence of successional events over small time and space scales. Although coastal systems may act differently from one another, our findings provide a conceptual framework to address physical-biological interactions occurring in coastal basins, which can be generalised to other areas.

Unfolding methods in high-energy physics experiments

International Nuclear Information System (INIS)

Blobel, V.

1985-01-01

Distributions measured in high-energy physics experiments are often distorted or transformed by limited acceptance and finite resolution of the detectors. The unfolding of measured distributions is an important, but due to inherent instabilities a very difficult problem. Methods for unfolding, applicable for the analysis of high-energy physics experiments, and their properties are discussed. An introduction is given to the method of regularization. (orig.)

Unfolding methods in high-energy physics experiments

International Nuclear Information System (INIS)

Blobel, V.

1984-12-01

Distributions measured in high-energy physics experiments are often distorted or transformed by limited acceptance and finite resolution of the detectors. The unfolding of measured distributions is an important, but due to inherent instabilities a very difficult problem. Methods for unfolding, applicable for the analysis of high-energy physics experiments, and their properties are discussed. An introduction is given to the method of regularization. (orig.)

A Comparison of Biological and Physical Risk Factors for Cardiovascular Disease in Overweight/Obese Individuals With and Without Prediabetes.

Science.gov (United States)

Liu, Tingting

2017-12-01

Compared with type 2 diabetes, evaluating the direct biological and physical risk factors for cardiovascular disease (CVD) in overweight/obese adults with and without prediabetes is less understood. Therefore, the aim of the study was to compare baseline biological and physical risk factors for CVD among overweight/obese adults with and without prediabetes. A secondary data analysis was performed. Three hundred forty-one overweight/obese participants were included in the analysis. Compared with non-prediabetics, prediabetics had higher fasting blood glucose, body mass index, waist-to-hip ratio, and triglycerides. Prediabetics were also more likely to be insulin resistant than non-prediabetics. Participants with prediabetes had much lower cardiorespiratory fitness than those without prediabetes. Findings from this study suggest that healthy overweight/obese adults with prediabetes were likely at higher biological and physical risk of CVD at baseline compared with those without prediabetes. Early intervention to improve CVD risk progression among persons with prediabetes is essential.

Life as physics and chemistry: A system view of biology.

Science.gov (United States)

Baverstock, Keith

2013-04-01

Cellular life can be viewed as one of many physical natural systems that extract free energy from their environments in the most efficient way, according to fundamental physical laws, and grow until limited by inherent physical constraints. Thus, it can be inferred that it is the efficiency of this process that natural selection acts upon. The consequent emphasis on metabolism, rather than replication, points to a metabolism-first origin of life with the adoption of DNA template replication as a second stage development. This order of events implies a cellular regulatory system that pre-dates the involvement of DNA and might, therefore, be based on the information acquired as peptides fold into proteins, rather than on genetic regulatory networks. Such an epigenetic cell regulatory model, the independent attractor model, has already been proposed to explain the phenomenon of radiation induced genomic instability. Here it is extended to provide an epigenetic basis for the morphological and functional diversity that evolution has yielded, based on natural selection of the most efficient free energy transduction. Empirical evidence which challenges the current genetic basis of cell and molecular biology and which supports the above proposal is discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Industrial applications of neutron physics methods

International Nuclear Information System (INIS)

Gozani, T.

1994-01-01

Three areas where nuclear based techniques have significant are briefly described. These are: Nuclear material control and non-proliferation, on-line elemental analysis of coal and minerals, and non- detection of explosives and other contraband. The nuclear physics and the role of reactor physics methods are highlighted. (author). 5 refs., 10 figs., 5 tabs

Radiation physics, biophysics, and radiation biology

International Nuclear Information System (INIS)

Hall, E.J.; Zaider, M.; Delegianis, M.J.

1989-07-01

An important event of the year was the designation of our Laboratory as a Center for Radiological Research by the Dean of the Faculty of Medicine and Vice-President for Health Sciences. Center status acknowledges the size and importance of the research efforts in this area, and allows a greater measure of independence in administrative matters. While the name has changed from a Laboratory to a Center within the Medical School, the mission and charge remain the same. The efforts of the Center are a multidisciplinary mix of physics, chemistry, and biology, mostly at a basic level, with the admixture of a small proportion of pragmatic or applied research in support of radiation protection or radiation therapy. About a quarter of our funding, mostly individual research awards, could be regarded as in direct support of radiotherapy, with the remainder (an NCI program project grant and DOE grants) being in support of research addressing more basic issues. An important effort currently underway concerns ab-initio calculations of the dielectric response function of condensed water. This investigation has received the coveted designation, ''Grand Challenge Project,'' awarded by DOE to research work which represents ''distinct advance on a major scientific or engineering problem that is broadly recognized as important within the mission of the Department.''

Quantum Processes and Dynamic Networks in Physical and Biological Systems.

Science.gov (United States)

Dudziak, Martin Joseph

Quantum theory since its earliest formulations in the Copenhagen Interpretation has been difficult to integrate with general relativity and with classical Newtonian physics. There has been traditionally a regard for quantum phenomena as being a limiting case for a natural order that is fundamentally classical except for microscopic extrema where quantum mechanics must be applied, more as a mathematical reconciliation rather than as a description and explanation. Macroscopic sciences including the study of biological neural networks, cellular energy transports and the broad field of non-linear and chaotic systems point to a quantum dimension extending across all scales of measurement and encompassing all of Nature as a fundamentally quantum universe. Theory and observation lead to a number of hypotheses all of which point to dynamic, evolving networks of fundamental or elementary processes as the underlying logico-physical structure (manifestation) in Nature and a strongly quantized dimension to macroscalar processes such as are found in biological, ecological and social systems. The fundamental thesis advanced and presented herein is that quantum phenomena may be the direct consequence of a universe built not from objects and substance but from interacting, interdependent processes collectively operating as sets and networks, giving rise to systems that on microcosmic or macroscopic scales function wholistically and organically, exhibiting non-locality and other non -classical phenomena. The argument is made that such effects as non-locality are not aberrations or departures from the norm but ordinary consequences of the process-network dynamics of Nature. Quantum processes are taken to be the fundamental action-events within Nature; rather than being the exception quantum theory is the rule. The argument is also presented that the study of quantum physics could benefit from the study of selective higher-scale complex systems, such as neural processes in the brain

Biological scaling and physics

Indian Academy of Sciences (India)

Unknown

Conversely, the average life-span, which is inverse to the ... Some find the catchy “life has an added dimension” (West et al ... works argument, which applies even outside biology, has .... While accounting for the (– 1/4) power, the thread of.

Differences in biological maturation, anthropometry and physical performance between playing positions in youth team handball

NARCIS (Netherlands)

Matthys, S.P.; Fransen, J.; Vaeyens, R.; Lenoir, M.; Philippaerts, R.

2013-01-01

It was the goal of this cross-sectional study to examine differences in maturity, anthropometry and physical performance between youth handball players across different playing positions (i.e. goalkeeper, back, pivot and wing). Multivariate analysis of covariance (MANCOVA), accounting for biological

Effects of Physical Exercise on Cognitive Functioning and Wellbeing: Biological and Psychological Benefits

Directory of Open Access Journals (Sweden)

Laura Mandolesi

2018-04-01

Full Text Available Much evidence shows that physical exercise (PE is a strong gene modulator that induces structural and functional changes in the brain, determining enormous benefit on both cognitive functioning and wellbeing. PE is also a protective factor for neurodegeneration. However, it is unclear if such protection is granted through modifications to the biological mechanisms underlying neurodegeneration or through better compensation against attacks. This concise review addresses the biological and psychological positive effects of PE describing the results obtained on brain plasticity and epigenetic mechanisms in animal and human studies, in order to clarify how to maximize the positive effects of PE while avoiding negative consequences, as in the case of exercise addiction.

Biological effectiveness and application of heavy ions in radiation therapy described by a physical and biological model

International Nuclear Information System (INIS)

Olsen, K.J.; Hansen, J.W.

1982-12-01

A description is given of the physical basis for applying track structure theory in the determination of the effectiveness of heavy-ion irradiation of single- and multi-hit target systems. It will be shown that for applying the theory to biological systems the effectiveness of heavy-ion irradiation is inadequately described by an RBE-factor, whereas the complete formulation of the probability of survival must be used, as survival depends on both radiation quality and dose. The theoretical model of track structure can be used in dose-effect calculations for neutron-, high-LET, and low-LET radiation applied simultaneously in therapy. (author)

Problems of improving physical training at this stage of the transformation of the system of physical education

Directory of Open Access Journals (Sweden)

Oleksandr Aghyppo

2016-02-01

Full Text Available Purpose: building a system of recreational physical culture on the basis of taking into account the individual characteristics of physical development and physical condition of the local population. Material & Methods: analytical review of the scientific literature on the issue of the research; use the results of previous studies carried out in KSAFC in this area and published in «Slobozhanskyi science and sport bulletin» during 2015 year; the use methods of similarity and analogy, also signs semantic spaces. Results: insolubility of the problem individual approach in organizing recreational physical culture in the previous period explained lack of representation of the content of individual of norm in the assessment of physical development and methods of comparison measure the differences being compared multicomponent objects. In held scientific research were developed signs semantic spaces with the introducted in its a single measure of comparable signs it possible to establish the qualitative structure of objects to be compared with any number of comparable parameters. Obtained methods separation of equifinality results into its component quality components. It is possible to obtain methods of estimating the biological age with the establishment of the individual characteristics of its course; divide the physical condition of its component parts; obtain methods for determining the available physical preparedness depending on the characteristics of the flow of biological age and current physical condition. Conclusions: Obtained results of the research make it possible to proceed to the development of monitoring physical development, physical preparedness and physical condition of the various population groups and on this basis to create a scientifically based of system improving physical training on the basis of which to develop a complex of "ready to work and defense of the fatherland".

Analysis and assessment of the detriment in interventional radiology using biological dosimetry methods

International Nuclear Information System (INIS)

Montoro, A.; Almonacid, M.; Villaescusa, J.I.; Barquinero, J.F.; Rodriguez, P.; Barrios, L.; Verdu, G.; Ramos, M.

2006-01-01

Interventional radiologist and staff members usually are exposed to high levels of scattered radiation. As a result, the exposition to radiation procedures can produce detrimental effects that we would have to know. Effective dose is the quantity that better estimates the radiation risk. For this study we have realized an estimation of the radiological detriment to exposed workers of the Hospital la Fe de Valencia. For it, have been used physical doses registered in detectors T.L.D., and doses estimated by biological dosimetry in lymphocytes of peripheral blood. There has been estimated for every case the probability of effect of skin cancer and of non-solid cancers (leukaemia, lymphoma and myeloma), being compared with the baseline probability of natural effect. Biological doses were obtained by extrapolating the yield of dicentrics and translocations to their respective dose -effect curves. The discrepancies observed between physically recorded doses and biological estimated doses indicate that workers did not always wear their dosimeters or the dosimeters were not always in the radiation field. Cytogenetic studies should be extended to more workers to assess the risk derived from their occupational exposure. (authors)

Analysis and assessment of the detriment in interventional radiology using biological dosimetry methods

Energy Technology Data Exchange (ETDEWEB)

Montoro, A.; Almonacid, M.; Villaescusa, J.I. [Hospital Univ. la Fe de Valen cian, Servicio de Proteccion Radiologica, Valencia (Spain); Barquinero, J.F.; Rodriguez, P. [Universitat Autonom a de Barcelona, Servicio de Dosimetria Biologica, Unidad de Antropologia, Departamento de Biologia Animal, Vegetal y Ecologia., Barcelona (Spain); Barrios, L. [Universidad Autonoma de Barcelona, Dept. de Biologia Celular y Fisiologia. Unidad de Biologia Celular, Barcelona (Spain); Verdu, G.; Ramos, M. [Universidad Politecnica de Valencia, Dept. de Ingenieria Quimica y Nuclear, Valencia, (Spain)

2006-07-01

Interventional radiologist and staff members usually are exposed to high levels of scattered radiation. As a result, the exposition to radiation procedures can produce detrimental effects that we would have to know. Effective dose is the quantity that better estimates the radiation risk. For this study we have realized an estimation of the radiological detriment to exposed workers of the Hospital la Fe de Valencia. For it, have been used physical doses registered in detectors T.L.D., and doses estimated by biological dosimetry in lymphocytes of peripheral blood. There has been estimated for every case the probability of effect of skin cancer and of non-solid cancers (leukaemia, lymphoma and myeloma), being compared with the baseline probability of natural effect. Biological doses were obtained by extrapolating the yield of dicentrics and translocations to their respective dose -effect curves. The discrepancies observed between physically recorded doses and biological estimated doses indicate that workers did not always wear their dosimeters or the dosimeters were not always in the radiation field. Cytogenetic studies should be extended to more workers to assess the risk derived from their occupational exposure. (authors)

Biological Remediation of Petroleum Contaminants

Science.gov (United States)

Kuhad, Ramesh Chander; Gupta, Rishi

Large volumes of hazardous wastes are generated in the form of oily sludges and contaminated soils during crude oil transportation and processing. Although many physical, chemical and biological treatment technologies are available for petroleum contaminants petroleum contaminants in soil, biological methods have been considered the most cost-effective. Practical biological remediation methods typically involve direct use of the microbes naturally occurring in the contaminated environment and/or cultured indigenous or modified microorganisms. Environmental and nutritional factors, including the properties of the soil, the chemical structure of the hydrocarbon(s), oxygen, water, nutrient availability, pH, temperature, and contaminant bioavailability, can significantly affect the rate and the extent of hydrocarbon biodegradation hydrocarbon biodegradation by microorganisms in contaminated soils. This chapter concisely discusses the major aspects of bioremediation of petroleum contaminants.

Physical, biological and clinical basis of light ions using in radiotherapy: EULIMA project

International Nuclear Information System (INIS)

Chauvel, P.

1991-01-01

Improving the efficiency of radiotherapy is a constant concern in oncology: more than half of the patients who contract cancer receive radiotherapy at some stage. Use of charged particles in radiotherapy represents indisputable progress in localization of the dose delivered to tumour masses, thereby allowing reduction of dose received by adjacent healthy tissues. Protons improve the physical selectivity of the irradiation, i.e. the dose distribution. High-LET (Linear Energy Transfer) radiations produce different biological effects, decreasing the differences in radiosensitivity, and allowing radiation therapy to control radioresistant tumours. Fast neutrons represent the most known of these high-LET particles, but they suffer of a relatively poor physical selectivity. The two approaches (physical selectivity and biological advantages) are joined in by light ions (Carbon, Oxygen, Neon). Highly selective high-LET radiation therapy can be performed for radioresistant tumours without damage to healthy tissues. Preliminary results obtained in Berkeley (USA) demonstrate an improved local control of unresectable, slowly growing tumours, confirming what could be extrapolated from proton and neutrontherapy. Furthermore, radioactive light ion beams can be used to verify the accuracy of treatment planning by checking the range of the particle with a PET camera, and in the future for the treatment itself. In the framework of its programme Europe against Cancer, the Commission of the European Communities participates in the funding of the EULIMA (European Light Ion Medical Accelerator) project feasibility study, aiming to design an hospital-based light ion therapy facility in Europe [fr

Physics and my method

CERN Document Server

Feldenkrais, Moshé

1981-01-01

Moshe Feldenkrais is known from the textbooks as a collaborator of Joliot-Curie, Langevin, and Kowarski participating in the first nuclear fission experiments. During the war he went to Great Britain and worked on the development of submarine detection devices. From experimental physics, following finally a suggestion of Lew Kowarski, he turned his interest to neurophysiology and neuropsychology. He studied the cybernetical organisation between human body dynamics and the mind. He developed his method known as "Functional integration" and "Awareness through movement". It has been applied with surprising results to post-traumatic rehabilitation, psychotherapy, re-education of the mentally or physically handicapped, and improvement of performance in sports. It can be used by everybody who wants to discover his natural grace of movement.

A Cluster Randomized Controlled Trial on the Effects of Technology-aided Testing and Feedback on Physical Activity and Biological Age Among Employees in a Medium-sized Enterprise.

Science.gov (United States)

Liukkonen, Mika; Nygård, Clas-Håkan; Laukkanen, Raija

2017-12-01

It has been suggested that engaging technology can empower individuals to be more proactive about their health and reduce their health risks. The aim of the present intervention was to study the effects of technology-aided testing and feedback on physical activity and biological age of employees in a middle-sized enterprise. In all, 121 employees (mean age 42 ± 10 years) participated in the 12-month three-arm cluster randomized trial. The fitness measurement process (Body Age) determined the participants' biological age in years. Physical activity was measured with the International Physical Activity Questionnaire Short Form. Physical activity did not change during the intervention. Biological age (better fitness) improved in all groups statistically significantly ( p  physical activity but may enhance physical fitness measured by biological age.

2010 Diffraction Methods in Structural Biology

Energy Technology Data Exchange (ETDEWEB)

Dr. Ana Gonzalez

2011-03-10

Advances in basic methodologies have played a major role in the dramatic progress in macromolecular crystallography over the past decade, both in terms of overall productivity and in the increasing complexity of the systems being successfully tackled. The 2010 Gordon Research Conference on Diffraction Methods in Structural Biology will, as in the past, focus on the most recent developments in methodology, covering all aspects of the process from crystallization to model building and refinement, complemented by examples of structural highlights and complementary methods. Extensive discussion will be encouraged and it is hoped that all attendees will participate by giving oral or poster presentations, the latter using the excellent poster display area available at Bates College. The relatively small size and informal atmosphere of the meeting provides an excellent opportunity for all participants, especially younger scientists, to meet and exchange ideas with leading methods developers.

The relative biological effectiveness of antiprotons

DEFF Research Database (Denmark)

Holzscheiter, Michael H.; Alsner, Jan; Bassler, Niels

2016-01-01

Background and purpose: Aside from the enhancement of physical dose deposited by antiprotons annihilating in tissue-like material compared to protons of the same range a further increase of biological effective dose has been demonstrated. This enhancement can be expressed in an increase of the re......Background and purpose: Aside from the enhancement of physical dose deposited by antiprotons annihilating in tissue-like material compared to protons of the same range a further increase of biological effective dose has been demonstrated. This enhancement can be expressed in an increase...... of the relative biological effectiveness (RBE) of antiprotons near the end of range. We have performed the first-ever direct measurement of the RBE of antiprotons both at rest and in flight. Materials and methods: Experimental data were generated on the RBE of an antiproton beam entering a tissue-like target...

ACTIVE AND PARTICIPATORY METHODS IN BIOLOGY: PROBLEM-SOLVING

Directory of Open Access Journals (Sweden)

Adela NEMEŞ

2010-01-01

Full Text Available We face with considerable challenge of developing students’ problem solving skills in our difficult environment. Good problem solving skills empower managers in their professional and personal lives. Problem solving skills are valued by academics and employers. The informations in Biology are often presented in abstract forms without contextualisation. Creative problem-solving process involves a few steps, which together provide a structured procedure for identifying challenges, generating ideas and implementing innovative solutions: identifying the problem, searching for possible solutions, selecting the most optimal solution and implementing a possible solution. Each aspect of personality has a different orientation to problem solving, different criteria for judging the effectiveness of the process and different associated strengths. Using real-world data in sample problems will also help facilitate the transfer process, since students can more easily identify with the context of a given situation. The paper describes the use of the Problem-Solving in Biology and the method of its administration. It also presents the results of a study undertaken to evaluate the value in teaching Biology. Problem-solving is seen as an essential skill that is developed in biology education.

Evaluation of methods to assess physical activity

Science.gov (United States)

Leenders, Nicole Y. J. M.

Epidemiological evidence has accumulated that demonstrates that the amount of physical activity-related energy expenditure during a week reduces the incidence of cardiovascular disease, diabetes, obesity, and all-cause mortality. To further understand the amount of daily physical activity and related energy expenditure that are necessary to maintain or improve the functional health status and quality of life, instruments that estimate total (TDEE) and physical activity-related energy expenditure (PAEE) under free-living conditions should be determined to be valid and reliable. Without evaluation of the various methods that estimate TDEE and PAEE with the doubly labeled water (DLW) method in females there will be eventual significant limitations on assessing the efficacy of physical activity interventions on health status in this population. A triaxial accelerometer (Tritrac-R3D, (TT)), an uniaxial (Computer Science and Applications Inc., (CSA)) activity monitor, a Yamax-Digiwalker-500sp°ler , (YX-stepcounter), by measuring heart rate responses (HR method) and a 7-d Physical Activity Recall questionnaire (7-d PAR) were compared with the "criterion method" of DLW during a 7-d period in female adults. The DLW-TDEE was underestimated on average 9, 11 and 15% using 7-d PAR, HR method and TT. The underestimation of DLW-PAEE by 7-d PAR was 21% compared to 47% and 67% for TT and YX-stepcounter. Approximately 56% of the variance in DLW-PAEE*kgsp{-1} is explained by the registration of body movement with accelerometry. A larger proportion of the variance in DLW-PAEE*kgsp{-1} was explained by jointly incorporating information from the vertical and horizontal movement measured with the CSA and Tritrac-R3D (rsp2 = 0.87). Although only a small amount of variance in DLW-PAEE*kgsp{-1} is explained by the number of steps taken per day, because of its low cost and ease of use, the Yamax-stepcounter is useful in studies promoting daily walking. Thus, studies involving the

Nanoscale technology in biological systems

CERN Document Server

Greco, Ralph S; Smith, R Lane

2004-01-01

Reviewing recent accomplishments in the field of nanobiology Nanoscale Technology in Biological Systems introduces the application of nanoscale matrices to human biology. It focuses on the applications of nanotechnology fabrication to biomedical devices and discusses new physical methods for cell isolation and manipulation and intracellular communication at the molecular level. It also explores the application of nanobiology to cardiovascular diseases, oncology, transplantation, and a range of related disciplines. This book build a strong background in nanotechnology and nanobiology ideal for

Quantitative X-ray microanalysis of biological specimens

International Nuclear Information System (INIS)

Roomans, G.M.

1988-01-01

Qualitative X-ray microanalysis of biological specimens requires an approach that is somewhat different from that used in the materials sciences. The first step is deconvolution and background subtraction on the obtained spectrum. The further treatment depends on the type of specimen: thin, thick, or semithick. For thin sections, the continuum method of quantitation is most often used, but it should be combined with an accurate correction for extraneous background. However, alternative methods to determine local mass should also be considered. In the analysis of biological bulk specimens, the ZAF-correction method appears to be less useful, primarily because of the uneven surface of biological specimens. The peak-to-local background model may be a more adequate method for thick specimens that are not mounted on a thick substrate. Quantitative X-ray microanalysis of biological specimens generally requires the use of standards that preferably should resemble the specimen in chemical and physical properties. Special problems in biological microanalysis include low count rates, specimen instability and mass loss, extraneous contributions to the spectrum, and preparative artifacts affecting quantitation. A relatively recent development in X-ray microanalysis of biological specimens is the quantitative determination of local water content

Synthetic biological networks

International Nuclear Information System (INIS)

Archer, Eric; Süel, Gürol M

2013-01-01

Despite their obvious relationship and overlap, the field of physics is blessed with many insightful laws, while such laws are sadly absent in biology. Here we aim to discuss how the rise of a more recent field known as synthetic biology may allow us to more directly test hypotheses regarding the possible design principles of natural biological networks and systems. In particular, this review focuses on synthetic gene regulatory networks engineered to perform specific functions or exhibit particular dynamic behaviors. Advances in synthetic biology may set the stage to uncover the relationship of potential biological principles to those developed in physics. (review article)

The method validation step of biological dosimetry accreditation process

International Nuclear Information System (INIS)

Roy, L.; Voisin, P.A.; Guillou, A.C.; Busset, A.; Gregoire, E.; Buard, V.; Delbos, M.; Voisin, Ph.

2006-01-01

One of the missions of the Laboratory of Biological Dosimetry (L.D.B.) of the Institute for Radiation and Nuclear Safety (I.R.S.N.) is to assess the radiological dose after an accidental overexposure suspicion to ionising radiation, by using radio-induced changes of some biological parameters. The 'gold standard' is the yield of dicentrics observed in patients lymphocytes, and this yield is converted in dose using dose effect relationships. This method is complementary to clinical and physical dosimetry, for medical team in charge of the patients. To obtain a formal recognition of its operational activity, the laboratory decided three years ago, to require an accreditation, by following the recommendations of both 17025 General Requirements for the Competence of Testing and Calibration Laboratories and 19238 Performance criteria for service laboratories performing biological dosimetry by cyto-genetics. Diagnostics, risks analysis were realized to control the whole analysis process leading to documents writing. Purchases, personnel department, vocational training were also included in the quality system. Audits were very helpful to improve the quality system. One specificity of this technique is that it is not normalized therefore apart from quality management aspects, several technical points needed some validations. An inventory of potentially influent factors was carried out. To estimate their real effect on the yield of dicentrics, a Placket-Burman experimental design was conducted. The effect of seven parameters was tested: the BUdr (bromodeoxyuridine), PHA (phytohemagglutinin) and colcemid concentration, the culture duration, the incubator temperature, the blood volume and the medium volume. The chosen values were calculated according to the uncertainties on the way they were measured i.e. pipettes, thermometers, test tubes. None of the factors has a significant impact on the yield of dicentrics. Therefore the uncertainty linked to their use was considered as

The method validation step of biological dosimetry accreditation process

Energy Technology Data Exchange (ETDEWEB)

Roy, L.; Voisin, P.A.; Guillou, A.C.; Busset, A.; Gregoire, E.; Buard, V.; Delbos, M.; Voisin, Ph. [Institut de Radioprotection et de Surete Nucleaire, LDB, 92 - Fontenay aux Roses (France)

2006-07-01

One of the missions of the Laboratory of Biological Dosimetry (L.D.B.) of the Institute for Radiation and Nuclear Safety (I.R.S.N.) is to assess the radiological dose after an accidental overexposure suspicion to ionising radiation, by using radio-induced changes of some biological parameters. The 'gold standard' is the yield of dicentrics observed in patients lymphocytes, and this yield is converted in dose using dose effect relationships. This method is complementary to clinical and physical dosimetry, for medical team in charge of the patients. To obtain a formal recognition of its operational activity, the laboratory decided three years ago, to require an accreditation, by following the recommendations of both 17025 General Requirements for the Competence of Testing and Calibration Laboratories and 19238 Performance criteria for service laboratories performing biological dosimetry by cyto-genetics. Diagnostics, risks analysis were realized to control the whole analysis process leading to documents writing. Purchases, personnel department, vocational training were also included in the quality system. Audits were very helpful to improve the quality system. One specificity of this technique is that it is not normalized therefore apart from quality management aspects, several technical points needed some validations. An inventory of potentially influent factors was carried out. To estimate their real effect on the yield of dicentrics, a Placket-Burman experimental design was conducted. The effect of seven parameters was tested: the BUdr (bromodeoxyuridine), PHA (phytohemagglutinin) and colcemid concentration, the culture duration, the incubator temperature, the blood volume and the medium volume. The chosen values were calculated according to the uncertainties on the way they were measured i.e. pipettes, thermometers, test tubes. None of the factors has a significant impact on the yield of dicentrics. Therefore the uncertainty linked to their use was

Application of biological dose concept in dose optimization for conformal radiotherapy of prostate carcinoma

International Nuclear Information System (INIS)

Li Yunhai; Liao Yuan; Zhou Lijun; Pan Ziqiang; Feng Yan

2003-01-01

Objective: On basis of physical dose optimization, LQ model was used to investigate the difference between the curves of biological effective dose and physical isodose. The influence of applying the biological dose concept on three dimensional conformal radiotherapy of prostate carcinoma was discussed. Methods: Four treatment plannings were designed for physical dose optimization: three fields, four-box fields, five fields and six fields. Target dose uniformity and protection of the critical tissue-rectum were used as the principal standard for designing the treatment planning. Biological effective dose (BED) was calculated by LQ model. The difference between the BED curve drawn in the central layer and the physical isodose curve was studied. The difference between the adjusted physical dose (APD) and the physical dose was also studied. Results: Five field planning was the best in target dose uniformity and protection of the critical tissue-rectum. The physical dose was uniform in the target, but the biological effective doses revealed great discrepancy in the biological model. Adjusted physical dose distribution also displayed larger discrepancy than the physical dose unadjusted. Conclusions: Intensified Modulated Radiotherapy (IMRT) technique with inversion planning using biological dose concept may be much more advantageous to reach a high tumor control probability and low normal tissue complication probability

Physics, radiology, and chemistry. 5. ed.

International Nuclear Information System (INIS)

Linde, O.K.; Knigge, H.J.

1978-01-01

This book is an introduction into physics and chemistry especially for medical personnel. After a general introduction, measurement methods, mechanics including mechanics of colid bodies, fluids and gases, heat, optics, acoustics, electricity, radiations including their biological effects, general chemistry, anorganic and organic chemistry are treated. Every chapter contains exercises mostly in connection with medical and biological effects. Futhermore connections with biology and medicine are considered. (HSI) [de

Geometric Methods in Physics : XXXIII Workshop

CERN Document Server

Bieliavsky, Pierre; Odzijewicz, Anatol; Schlichenmaier, Martin; Voronov, Theodore

2015-01-01

This book presents a selection of papers based on the XXXIII Białowieża Workshop on Geometric Methods in Physics, 2014. The Białowieża Workshops are among the most important meetings in the field and attract researchers from both mathematics and physics. The articles gathered here are mathematically rigorous and have important physical implications, addressing the application of geometry in classical and quantum physics. Despite their long tradition, the workshops remain at the cutting edge of ongoing research. For the last several years, each Białowieża Workshop has been followed by a School on Geometry and Physics, where advanced lectures for graduate students and young researchers are presented; some of the lectures are reproduced here. The unique atmosphere of the workshop and school is enhanced by its venue, framed by the natural beauty of the Białowieża forest in eastern Poland. The volume will be of interest to researchers and graduate students in mathematical physics, theoretical physics and m...

Predicting Salmonella populations from biological, chemical, and physical indicators in Florida surface waters.

Science.gov (United States)

McEgan, Rachel; Mootian, Gabriel; Goodridge, Lawrence D; Schaffner, Donald W; Danyluk, Michelle D

2013-07-01

Coliforms, Escherichia coli, and various physicochemical water characteristics have been suggested as indicators of microbial water quality or index organisms for pathogen populations. The relationship between the presence and/or concentration of Salmonella and biological, physical, or chemical indicators in Central Florida surface water samples over 12 consecutive months was explored. Samples were taken monthly for 12 months from 18 locations throughout Central Florida (n = 202). Air and water temperature, pH, oxidation-reduction potential (ORP), turbidity, and conductivity were measured. Weather data were obtained from nearby weather stations. Aerobic plate counts and most probable numbers (MPN) for Salmonella, E. coli, and coliforms were performed. Weak linear relationships existed between biological indicators (E. coli/coliforms) and Salmonella levels (R(2) Florida surface water through logistic regression.

The Hanford Nuclear Reservation (1943-1987): a case study of the interface between physics and biology during the cold war

Energy Technology Data Exchange (ETDEWEB)

Macuglia, Daniele [Fishbein Center for the History of Science and Medicine, University of Chicago, IL (United States)

2011-07-01

During its active period (1943-1987) the Hanford Nuclear Reservation shaped the history of US nuclear research. It also constitutes an interesting case study of the interface between physics, biology and the politics of Cold War society. Although supposed to turn the US into a stronger military force during the Cold War, the remarkable biological consequences of the nuclear research carried out in the facility ended up overshadowing its original political purpose. The high-level of radioactive waste harmed thousands of people living in the area, causing relevant environmental disasters which make the site the most contaminated area in the US even today. Nuclear research is uniquely dangerous since radiation can cause severe consequences both in terms of lives injured and environmental damage. I address various ways in which nuclear physics and biology were used - and abused - at the Hanford Site to combine the needs of politics with the needs of a healthy society. This paper further investigates the moral responsibility of science to society and the way in which biological research informed nuclear physics about the deleterious consequences of radiation on environment and on the human body.

Undergraduate Labs for Biological Physics: Brownian Motion and Optical Trapping

Science.gov (United States)

Chu, Kelvin; Laughney, A.; Williams, J.

2006-12-01

We describe a set of case-study driven labs for an upper-division biological physics course. These labs are motivated by case-studies and consist of inquiry-driven investigations of Brownian motion and optical-trapping experiments. Each lab incorporates two innovative educational techniques to drive the process and application aspects of scientific learning. Case studies are used to encourage students to think independently and apply the scientific method to a novel lab situation. Student input from this case study is then used to decide how to best do the measurement, guide the project and ultimately evaluate the success of the program. Where appropriate, visualization and simulation using VPython is used. Direct visualization of Brownian motion allows students to directly calculate Avogadro's number or the Boltzmann constant. Following case-study driven discussion, students use video microscopy to measure the motion of latex spheres in different viscosity fluids arrive at a good approximation of NA or kB. Optical trapping (laser tweezer) experiments allow students to investigate the consequences of 100-pN forces on small particles. The case study consists of a discussion of the Boltzmann distribution and equipartition theorem followed by a consideration of the shape of the potential. Students can then use video capture to measure the distribution of bead positions to determine the shape and depth of the trap. This work supported by NSF DUE-0536773.

Treatment plan ranking using physical and biological indices

International Nuclear Information System (INIS)

Ebert, M. A.; University of Western Asutralia, WA

2001-01-01

Full text: The ranking of dose distributions is of importance in several areas such as i) comparing rival treatment plans, ii) comparing iterations in an optimisation routine, and iii) dose-assessment of clinical trial data. This study aimed to investigate the influence of choice of objective function in ranking tumour dose distributions. A series of physical (mean, maximum, minimum, standard deviation of dose) dose-volume histogram (DVH) reduction indices and biologically-based (tumour-control probability - TCP; equivalent uniform dose -EUD) indices were used to rank a series of hypothetical DVHs, as well as DVHs obtained from a series of 18 prostate patients. The distribution in ranking and change in distribution with change in indice parameters were investigated. It is found that not only is the ranking of DVHs dependent on the actual model used to perform the DVH reduction, it is also found to depend on the inherent characteristics of each model (i.e., selected parameters). The adjacent figure shows an example where the 18 prostate patients are ranked (grey-scale from black to white) by EUD when an α value of 0.8 Gy -1 is used in the model. The change of ranking as α varies is evident. Conclusion: This study has shown that the characteristics of the model selected in plan optimisation or DVH ranking will have an impact on the ranking obtained. Copyright (2001) Australasian College of Physical Scientists and Engineers in Medicine

Nuclear physics and biology

International Nuclear Information System (INIS)

Valentin, L.

1994-01-01

This paper is about nuclear instrumentation and biological concepts, based on images from appropriate Β detectors. First, three detectors are described: the SOFI detector, for gene mapping, the SOFAS detector, for DNA sequencing and the RIHR detector, for in situ hybridization. Then, the paper presents quantitative imaging in molecular genetic and functional imaging. (TEC)

Tritium in the Physical and Biological Sciences. V. 1. Proceedings of a Symposium

Energy Technology Data Exchange (ETDEWEB)

NONE

1962-01-15

The use of tritium for research in physics, chemistry, biology and hydrology has in recent years become increasingly important. It was for this reason that the first international conference to discuss the progress of new developments was organized by the IAEA in conjunction with the Joint Commission on Applied Radioactivity and held from 3-10 May 1961, in Vienna. The first five sessions of the Symposium were devoted to the use of tritium in hydrology, physics and chemistry. Special emphasis was laid on the role of tritium as a tracer in hydrology, especially in the study of water movement. The establishment and improvement of counting and detection techniques to facilitate the application of tritium as a tracer was another aspect discussed in this part of the proceedings. Papers were read on the preparation of tritiated compounds and it was generally agreed that further clarification of the mechanism of various techniques, and of the Wilzbach gas exposure technique in particular, would lead to further developments in the synthesis of a number of tritium compounds important in biology. Other papers were concerned with tritium applications to studies of the mechanism of some chemical reactions together with the effects of tritium isotopes. During the second part of the Symposium the biological applications of tritium and tritiated compounds were discussed. These included general problems connected with the biological uses of tritium and the radiation effects of tritium on living organisms such as viruses, bacteria and cancer cells. The value of tritium in biological studies became apparent because of the ease with which a large number of metabolically active compounds such as hormones, vitamins and other important constituents in the body can be labelled with tritium. Tritium is also a weak beta-emitter and autoradiographie s of tissues and single cells containing tritium-labelled compounds allow an excellent localization of the tracer. The Symposium was attended by

Application of cybernetic methods in physics

Energy Technology Data Exchange (ETDEWEB)

Fradkov, Aleksandr L [Institute of Problems of Mechanical Engineering, Russian Academy of Sciences, St.-Petersburg (Russian Federation)

2005-02-28

Basic aspects of the subject and methodology for a new and rapidly developing area of research that has emerged at the intersection of physics and control theory (cybernetics) and emphasizes the application of cybernetic methods to the study of physical systems are reviewed. Speed-gradient and Hamiltonian solutions for energy control problems in conservative and dissipative systems are presented. Application examples such as the Kapitza pendulum, controlled overcoming of a potential barrier, and controlling coupled oscillators and molecular systems are presented. A speed-gradient approach to modeling the dynamics of physical systems is discussed. (reviews of topical problems)

Application of cybernetic methods in physics

International Nuclear Information System (INIS)

Fradkov, Aleksandr L

2005-01-01

Basic aspects of the subject and methodology for a new and rapidly developing area of research that has emerged at the intersection of physics and control theory (cybernetics) and emphasizes the application of cybernetic methods to the study of physical systems are reviewed. Speed-gradient and Hamiltonian solutions for energy control problems in conservative and dissipative systems are presented. Application examples such as the Kapitza pendulum, controlled overcoming of a potential barrier, and controlling coupled oscillators and molecular systems are presented. A speed-gradient approach to modeling the dynamics of physical systems is discussed. (reviews of topical problems)

IBPRO - A Novel Short-Duration Teaching Course in Advanced Physics and Biology Underlying Cancer Radiotherapy.

Science.gov (United States)

Joiner, Michael C; Tracey, Monica W; Kacin, Sara E; Burmeister, Jay W

2017-06-01

This article provides a summary and status report of the ongoing advanced education program IBPRO - Integrated course in Biology and Physics of Radiation Oncology. IBPRO is a five-year program funded by NCI. It addresses the recognized deficiency in the number of mentors available who have the required knowledge and skill to provide the teaching and training that is required for future radiation oncologists and researchers in radiation sciences. Each year, IBPRO brings together 50 attendees typically at assistant professor level and upwards, who are already qualified/certified radiation oncologists, medical physicists or biologists. These attendees receive keynote lectures and activities based on active learning strategies, merging together the clinical, biological and physics underpinnings of radiation oncology, at the forefront of the field. This experience is aimed at increasing collaborations, raising the level and amount of basic and applied research undertaken in radiation oncology, and enabling attendees to confidently become involved in the future teaching and training of researchers and radiation oncologists.

Chitin Extraction from Crustacean Shells Using Biological Methods – A Review

Directory of Open Access Journals (Sweden)

Wassila Arbia

2013-01-01

Full Text Available After cellulose, chitin is the most widespread biopolymer in nature. Chitin and its derivatives have great economic value because of their biological activities and their industrial and biomedical applications. It can be extracted from three sources, namely crustaceans, insects and microorganisms. However, the main commercial sources of chitin are shells of crustaceans such as shrimps, crabs, lobsters and krill that are supplied in large quantities by the shellfish processing industries. Extraction of chitin involves two steps, demineralisation and deproteinisation, which can be conducted by two methods, chemical or biological. The chemical method requires the use of acids and bases, while the biological method involves microorganisms. Although lactic acid bacteria are mainly applied, other microbial species including proteolytic bacteria have also been successfully implemented, as well as mixed cultures involving lactic acid-producing bacteria and proteolytic microorganisms. The produced lactic acid allows shell demineralisation, since lactic acid reacts with calcium carbonate, the main mineral component, to form calcium lactate.

Treatment of laundry wastewater by biological and electrocoagulation methods.

Science.gov (United States)

Ramcharan, Terelle; Bissessur, Ajay

2017-01-01

The present study describes an improvement in the current electrocoagulation treatment process and focuses on a comparative study for the clean-up of laundry wastewater (LWW) after each wash and rinse cycle by biological and electrocoagulation treatment methods. For biological treatment, the wastewater was treated with a Bacillus strain of aerobic bacteria especially suited for the degradation of fats, lipids, protein, detergents and hydrocarbons. Treatment of the LWW by electrocoagulation involved the oxidation of aluminium metal upon the application of a controlled voltage which produces various aluminium hydroxy species capable of adsorbing pollutants from the wastewater. The efficiency of the clean-up of LWW using each method was assessed by determination of surfactant concentration, chemical oxygen demand and total dissolved solids. A rapid decrease in surfactant concentration was noted within 0.5 hour of electrocoagulation, whereas a notable decrease in the surfactant concentration was observed only after 12 hour of biological treatment. The rapid generation of aluminium hydroxy species in the electrocoagulation cell allowed adsorption of pollutants at a faster rate when compared to the aerobic degradation of the surfactant; hence a reduced period of time is required for treatment of LWW by electrocoagulation.

The effects of urbanization on the biological, physical, and chemical characteristics of coastal New England streams

Science.gov (United States)

Coles, James F.; Cuffney, Thomas F.; McMahon, Gerard; Beaulieu, Karen M.

2004-01-01

During August 2000, responses of biological communities (invertebrates, fish, and algae), physical habitat, and water chemistry to urban intensity were compared among 30 streams within 80 miles of Boston, Massachusetts. Sites chosen for sampling represented a gradient of the intensity of urban development (urban intensity) among drainage basins that had minimal natural variability. In this study, spatial differences were used as surrogates for temporal changes to represent the effects of urbanization over time. The degree of urban intensity for each drainage basin was characterized with a standardized urban index (0-100, lowest to highest) derived from land cover, infrastructure, and socioeconomic variables. Multivariate and multimetric analyses were used to compare urban index values with biological, physical, and chemical data to determine how the data indicated responses to urbanization. Multivariate ordinations were derived for the invertebrate-, fish-, and algae-community data by use of correspondence analysis, and ordinations were derived for the chemical and physical data by use of principal-component analysis. Site scores from each of the ordinations were plotted in relation to the urban index to test for a response. In all cases, the primary axis scores showed the strongest response to the urban index, indicating that urbanization was a primary factor affecting the data ordination. For the multimetric analyses, each of the biological data sets was used to calculate a series of community metrics. For the sets of chemical and physical data, the individual variables and various combinations of individual variables were used as measured and derived metrics, respectively. Metrics that were generally most responsive to the urban index for each data set included: EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa for invertebrates; cyprinid taxa for fish; diatom taxa for algae; bicarbonate, conductivity, and nitrogen for chemistry; and water depth and temperature

Nonequilibrium thermodynamics transport and rate processes in physical, chemical and biological systems

CERN Document Server

Demirel, Yasar

2014-01-01

Natural phenomena consist of simultaneously occurring transport processes and chemical reactions. These processes may interact with each other and may lead to self-organized structures, fluctuations, instabilities, and evolutionary systems. Nonequilibrium Thermodynamics, 3rd edition emphasizes the unifying role of thermodynamics in analyzing the natural phenomena. This third edition updates and expands on the first and second editions by focusing on the general balance equations for coupled processes of physical, chemical, and biological systems. The new edition contains a new chapte

Physical and biological pretreatment quality assurance of the head and neck cancer plan with the volumetric modulated arc therapy

Science.gov (United States)

Park, So-Hyun; Lee, Dong-Soo; Lee, Yun-Hee; Lee, Seu-Ran; Kim, Min-Ju; Suh, Tae-Suk

2015-09-01

The aim of this work is to demonstrate both the physical and the biological quality assurance (QA) aspects as pretreatment QA of the head and neck (H&N) cancer plan for the volumetric modulated arc therapy (VMAT). Ten H&N plans were studied. The COMPASS® dosimetry analysis system and the tumor control probability (TCP) and the normal tissue complication probability (NTCP) calculation free program were used as the respective measurement and calculation tools. The reliability of these tools was verified by a benchmark study in accordance with the TG-166 report. For the physical component of QA, the gamma passing rates and the false negative cases between the calculated and the measured data were evaluated. The biological component of QA was performed based on the equivalent uniform dose (EUD), TCP and NTCP values. The evaluation was performed for the planning target volumes (PTVs) and the organs at risks (OARs), including the eyes, the lens, the parotid glands, the esophagus, the spinal cord, and the brainstem. All cases had gamma passing rates above 95% at an acceptance tolerance level with the 3%/3 mm criteria. In addition, the false negative instances were presented for the PTVs and OARs. The gamma passing rates exhibited a weak correlation with false negative cases. For the biological QA, the physical dose errors affect the EUD and the TCP for the PTVs, but no linear correlation existed between them. The EUD and NTCP for the OARs were shown the random differences that could not be attributed to the dose errors from the physical QA. The differences in the EUD and NTCP between the calculated and the measured results were mainly demonstrated for the parotid glands. This study describes the importance and the necessity of improved QA to accompany both the physical and the biological aspects for accurate radiation treatment.

Using the Case Study Method in Teaching College Physics

Science.gov (United States)

Burko, Lior M.

2016-10-01

The case study teaching method has a long history (starting at least with Socrates) and wide current use in business schools, medical schools, law schools, and a variety of other disciplines. However, relatively little use is made of it in the physical sciences, specifically in physics or astronomy. The case study method should be considered by physics faculty as part of the effort to transition the teaching of college physics from the traditional frontal-lecture format to other formats that enhance active student participation. In this paper we endeavor to interest physics instructors in the case study method, and hope that it would also serve as a call for more instructors to produce cases that they use in their own classes and that can also be adopted by other instructors.

Predicting Salmonella Populations from Biological, Chemical, and Physical Indicators in Florida Surface Waters

OpenAIRE

McEgan, Rachel; Mootian, Gabriel; Goodridge, Lawrence D.; Schaffner, Donald W.; Danyluk, Michelle D.

2013-01-01

Coliforms, Escherichia coli, and various physicochemical water characteristics have been suggested as indicators of microbial water quality or index organisms for pathogen populations. The relationship between the presence and/or concentration of Salmonella and biological, physical, or chemical indicators in Central Florida surface water samples over 12 consecutive months was explored. Samples were taken monthly for 12 months from 18 locations throughout Central Florida (n = 202). Air and wat...

Nanophase materials produced by physical methods

International Nuclear Information System (INIS)

Noda, Shoji

1992-01-01

A nanophase material is mainly characterized by the component's size and the large interface area. Some nanophase materials are briefly described. Ion implantation and oblique vapor deposition are taken as the methods to provide nanophase materials, and their features are described. These physical methods are non-equilibrium material processes, and the unique nanophase materials are demonstrated to be provided by these methods with little thermodynamic restriction. (author)

Quantum Effects in Biological Systems

CERN Document Server

2016-01-01

Since the last decade the study of quantum mechanical phenomena in biological systems has become a vibrant field of research. Initially sparked by evidence of quantum effects in energy transport that is instrumental for photosynthesis, quantum biology asks the question of how methods and models from quantum theory can help us to understand fundamental mechanisms in living organisms. This approach entails a paradigm change challenging the related disciplines: The successful framework of quantum theory is taken out of its low-temperature, microscopic regimes and applied to hot and dense macroscopic environments, thereby extending the toolbox of biology and biochemistry at the same time. The Quantum Effects in Biological Systems conference is a platform for researchers from biology, chemistry and physics to present and discuss the latest developments in the field of quantum biology. After meetings in Lisbon (2009), Harvard (2010), Ulm (2011), Berkeley (2012), Vienna (2013), Singapore (2014) and Florence (2015),...

Project as an education method in teaching of physics

OpenAIRE

ŽAHOUREK, Martin

2011-01-01

The diploma thesis ?Project as an educational method for teaching physics ?deals with the possibilities of using project-based method for teaching physics at primary schools. Not only does it contain the theoretical background of project-based teaching, but also deals with practical issues in the form of an implementation of a chosen project ?Physics and physical education?. The aim of said project was to evaluate the efficiency of project-based teaching as far as the knowledge of pupils and ...

Measurement Frontiers in Molecular Biology

Science.gov (United States)

Laderman, Stephen

2009-03-01

Developments of molecular measurements and manipulations have long enabled forefront research in evolution, genetics, biological development and its dysfunction, and the impact of external factors on the behavior of cells. Measurement remains at the heart of exciting and challenging basic and applied problems in molecular and cell biology. Methods to precisely determine the identity and abundance of particular molecules amongst a complex mixture of similar and dissimilar types require the successful design and integration of multiple steps involving biochemical manipulations, separations, physical probing, and data processing. Accordingly, today's most powerful methods for characterizing life at the molecular level depend on coordinated advances in applied physics, biochemistry, chemistry, computer science, and engineering. This is well illustrated by recent approaches to the measurement of DNA, RNA, proteins, and intact cells. Such successes underlie well founded visions of how molecular biology can further assist in answering compelling scientific questions and in enabling the development of remarkable advances in human health. These visions, in turn, are motivating the interdisciplinary creation of even more comprehensive measurements. As a further and closely related consequence, they are motivating innovations in the conceptual and practical approaches to organizing and visualizing large, complex sets of interrelated experimental results and distilling from those data compelling, informative conclusions.

Network science of biological systems at different scales: A review

Science.gov (United States)

Gosak, Marko; Markovič, Rene; Dolenšek, Jurij; Slak Rupnik, Marjan; Marhl, Marko; Stožer, Andraž; Perc, Matjaž

2018-03-01

Network science is today established as a backbone for description of structure and function of various physical, chemical, biological, technological, and social systems. Here we review recent advances in the study of complex biological systems that were inspired and enabled by methods of network science. First, we present

Graduate student training and creating new physics labs for biology students, killing two birds with one stone.

Science.gov (United States)

Jones, Barbara

2001-03-01

At UCSD biology majors are required to take 3 quarters of a calculus based physics course. This is taught in a standard format large lecture class partly by faculty and partly by freeway flyers. We are working with physics graduate students who are also participating in our PFPF (Preparing Future Physics Faculty) program to write, review, and teach new weekly labs for these biology students. This provides an experience for the grad student that is both rewarding to them and useful to the department. The grad students participate in curriculum development, they observe the students behaviour in the labs, and assess the effectiveness of different lab formats. The labs are intended to provide an interactive, hands on experience with a wide variety of equipment which is mostly both simple and inexpensive. Both students and grads find the labs to be engaging and fun. Based on group discussions the labs are modified to try to try to create the best teaching environment. The biology students benefit from the improvements both in the quality of the labs they do, and from the enthusiasm of the TAs who take an active interest in their learning. The ability to make significant changes to the material taught maintains the interest of the grad students and helps to make the labs a stable and robust environment.

Method for increasing nuclear magnetic resonance signals in living biological tissue

International Nuclear Information System (INIS)

Krongrad, A.

1995-01-01

A method of enhancing a magnetic resonance comprising the steps of administering a quantity of a selected magnetic isotope to a living biological tissue at a concentration greater than the naturally occurring concentration of such isotope and detecting magnetic resonance signal from the administered magnetic isotope in the living biological tissue. (author)

Synthesis, physical-chemical and biological properties of 7-benzyl-3-methyl-8-thioxanthine derivatives

Directory of Open Access Journals (Sweden)

D. H. Ivanchenko

2017-12-01

Full Text Available Introduction . Interest to the problem of creating new effective antimicrobial agents among xanthine derivatives does not decrease. Primarily, this is due to the increasing of microbial resistance to conventional antimicrobial agents and the emergence of their new strains. In recent years interest to the therapeutic use of antioxidants in the treatment of diseases associated with oxidative stress has increased. The aim of this work is to elaborate simple laboratory methods of 7-benzyl-3-methyl-8-thioxanthine derivatives synthesis, unspecified in scientific papers earlier, and to study their physical, chemical and biological properties. Materials and methods. The melting point has been determined with the help of an open capillary method with PTP-M device. Elemental analysis has been performed with the help of the instrument Elementar Vario L cube, NMR-spectra have been taken on a spectrometer Bruker SF-400 (operating frequency of 400 MHz, solvent DMSO, internal standard – TMS. Study of antimicrobial and antifungal activity of synthesized compounds has been performed by two-fold serial dilution method. Standard test strains have been used for the study: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 885-653. Dimethylsulfoxide was used as the solvent of the compounds. Results. Under short-time heating up of the initial 7-benzyl-3-methyl-8-thioxanthine with alkyl, alkenyl, benzyl halides or heteroalkylchlorides in a water-propanol-2 mixture in the presence of an equimolar amount of sodium hydroxide leads to the formation of 8-S-substituted of 7-benzyl-3-methylxanthines. Structure of synthesized compounds was definitely proved by NMR-spectroscopy. We conducted primary screening research of antimicrobial activity of 7-benzyl-3-methyl-8-thioxanthine derivatives, which revealed moderate and weak activity in concentrations 50-100 mcg/ml. Most of the obtained compounds showed a

Interest in STEM is contagious for students in biology, chemistry, and physics classes.

Science.gov (United States)

Hazari, Zahra; Potvin, Geoff; Cribbs, Jennifer D; Godwin, Allison; Scott, Tyler D; Klotz, Leidy

2017-08-01

We report on a study of the effect of peers' interest in high school biology, chemistry, and physics classes on students' STEM (science, technology, engineering, and mathematics)-related career intentions and course achievement. We define an interest quorum as a science class where students perceive a high level of interest for the subject matter from their classmates. We hypothesized that students who experience such an interest quorum are more likely to choose STEM careers. Using data from a national survey study of students' experiences in high school science, we compared the effect of five levels of peer interest reported in biology, chemistry, and physics courses on students' STEM career intentions. The results support our hypothesis, showing a strong, positive effect of an interest quorum even after controlling for differences between students that pose competing hypotheses such as previous STEM career interest, academic achievement, family support for mathematics and science, and gender. Smaller positive effects of interest quorums were observed for course performance in some cases, with no detrimental effects observed across the study. Last, significant effects persisted even after controlling for differences in teaching quality. This work emphasizes the likely importance of interest quorums for creating classroom environments that increase students' intentions toward STEM careers while enhancing or maintaining course performance.

Interest in STEM is contagious for students in biology, chemistry, and physics classes

Science.gov (United States)

Hazari, Zahra; Potvin, Geoff; Cribbs, Jennifer D.; Godwin, Allison; Scott, Tyler D.; Klotz, Leidy

2017-01-01

We report on a study of the effect of peers’ interest in high school biology, chemistry, and physics classes on students’ STEM (science, technology, engineering, and mathematics)–related career intentions and course achievement. We define an interest quorum as a science class where students perceive a high level of interest for the subject matter from their classmates. We hypothesized that students who experience such an interest quorum are more likely to choose STEM careers. Using data from a national survey study of students‘ experiences in high school science, we compared the effect of five levels of peer interest reported in biology, chemistry, and physics courses on students‘ STEM career intentions. The results support our hypothesis, showing a strong, positive effect of an interest quorum even after controlling for differences between students that pose competing hypotheses such as previous STEM career interest, academic achievement, family support for mathematics and science, and gender. Smaller positive effects of interest quorums were observed for course performance in some cases, with no detrimental effects observed across the study. Last, significant effects persisted even after controlling for differences in teaching quality. This work emphasizes the likely importance of interest quorums for creating classroom environments that increase students’ intentions toward STEM careers while enhancing or maintaining course performance. PMID:28808678

Physical, chemical, and biological data collected in Weeks Bay, Alabama (June 1990 - May 2000) (NODC Accession 0116469)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Abstract: This dataset contains ten years of physical, chemical, and biological data collected during shipboard surveys in Weeks Bay, Alabama, between June 1990 and...

Interactions between physical, chemical and biological processes in aquatic systems - impacts on receiving waters with different contents of treated wastewater

International Nuclear Information System (INIS)

Kreuzinger, N.

2000-08-01

Two scenarios have be chosen within this PhD Thesis to describe the integrative key-significance of interactions between most relevant physical, chemical and biological processes in aquatic systems. These two case studies are used to illustrate and describe the importance of a detailed synthesis of biological, physical and chemical interactions in aquatic systems in order to provide relevant protection of water resources and to perform a sound water management. Methods are described to allow a detailed assessment of particular aspects within the complexity of the overall integration and therefore serve as a basis to determine the eventual necessity of proposed water management measures. Regarding the anthropogenic influence of treated wastewater on aquatic systems, one case study focuses on the interactions between emitted waters from a wastewater treatment plant and the resulting immission situation of its receiving water (The receiving water is quantitatively influenced by the treated wastewater by 95 %). This thesis proves that the effluent of wastewater treatment plants operated by best available technology meets the quality standards of running waters for the nutrients nitrogen and phosphorus, carbon-parameters, oxygen-regime and ecotoxicology. Within the second case study the focus is put on interactions between immissions and water usage. The general importance of biological phosphorus precipitation on the trophic situation of aquatic systems is described. Nevertheless, this generally known but within the field of applied limnology so far unrespected process of immobilization of phosphorus could be shown to represent a significant and major impact on phytoplannctotic development and eutrification. (author)

DNA as information: at the crossroads between biology, mathematics, physics and chemistry.

Science.gov (United States)

Cartwright, Julyan H E; Giannerini, Simone; González, Diego L

2016-03-13

On the one hand, biology, chemistry and also physics tell us how the process of translating the genetic information into life could possibly work, but we are still very far from a complete understanding of this process. On the other hand, mathematics and statistics give us methods to describe such natural systems-or parts of them-within a theoretical framework. Also, they provide us with hints and predictions that can be tested at the experimental level. Furthermore, there are peculiar aspects of the management of genetic information that are intimately related to information theory and communication theory. This theme issue is aimed at fostering the discussion on the problem of genetic coding and information through the presentation of different innovative points of view. The aim of the editors is to stimulate discussions and scientific exchange that will lead to new research on why and how life can exist from the point of view of the coding and decoding of genetic information. The present introduction represents the point of view of the editors on the main aspects that could be the subject of future scientific debate. © 2016 The Author(s).

Influence of bodybuilding classes on physical qualities of the qualified sportswomen in different phases of the specific biological cycle

Directory of Open Access Journals (Sweden)

Vyacheslav Mulik

2017-02-01

Full Text Available Purpose: to conduct researches of influence of classes of the sportswomen who are going in for bodybuilding and fitness-bikini on manifestation of physical qualities in different phases of the ovarian-menstrual cycle. Material & Methods: researches were conducted in sports fitness-clubs of Kharkov "Feromon", "Gorod", “King” with the qualified sportswomen who are going in for bodybuilding and fitness-bikini within 3 months of the preparatory period in number of 14 people. We used as methods of the research: the analysis of references and testing of level of motive qualities in separate phases of OMC. Results: the theoretical analysis of features of the accounting of phases of OMC at sportswomen is submitted and the testing of the level of development of physical qualities in different phases of the specific biological cycle at the qualified sportswomen, who are going in for bodybuilding, is held. Conclusions: the received results demonstrate that physical efficiency of the qualified sportswomen, who are going in for bodybuilding, is not identical in phases of the ovarian-menstrual cycle. It is revealed that the best conditions for performance of considerable exercise stresses in post-ovulatory and post-menstrual phases of OMC, therefore it is expedient to plan them in the preparatory periods of the qualified sportswomen, who are going in for bodybuilding.

Physical acoustics v.8 principles and methods

CERN Document Server

Mason, Warren P

1971-01-01

Physical Acoustics: Principles and Methods, Volume VIII discusses a number of themes on physical acoustics that are divided into seven chapters. Chapter 1 describes the principles and applications of a tool for investigating phonons in dielectric crystals, the spin phonon spectrometer. The next chapter discusses the use of ultrasound in investigating Landau quantum oscillations in the presence of a magnetic field and their relation to the strain dependence of the Fermi surface of metals. The third chapter focuses on the ultrasonic measurements that are made by pulsing methods with velo

Future Directions in Medical Physics

Science.gov (United States)

Jeraj, Robert

Medical Physics is a highly interdisciplinary field at the intersection between physics and medicine and biology. Medical Physics is aiming at development of novel applications of physical processes and techniques in various areas of medicine and biology. Medical Physics had and continues to have profound impact by developing improved imaging and treatment technologies, and helping to advance our understanding of the complexity of the disease. The general trend in medicine towards personalized therapy, and emphasis on accelerated translational research is having a profound impact on medical physics as well. In the traditional stronghold for medical physicists - radiation therapy - the new reality is shaping in the form of biologically conformal and combination therapies, as well as advanced particle therapy approaches, such as proton and ion therapies. Rapid increase in faster and more informative multi-modality medical imaging is bringing a wealth of information that is being complemented with data obtained from genomic profiling and other biomarkers. Novel data analysis and data mining approaches are proving grounds for employment of various artificial intelligence methods that will help further improving clinical decision making for optimization of various therapies as well as better understanding of the disease properties and disease evolution, ultimately leading to improved clinical outcomes.

Biological effects and physical safety aspects of NMR imaging and in vivo spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Tenforde, T.S.; Budinger, T.F.

1985-08-01

An assessment is made of the biological effects and physical hazards of static and time-varying fields associated with the NMR devices that are being used for clinical imaging and in vivo spectroscopy. A summary is given of the current state of knowledge concerning the mechanisms of interaction and the bioeffects of these fields. Additional topics that are discussed include: (1) physical effects on pacemakers and metallic implants such as aneurysm clips, (2) human health studies related to the effects of exposure to nonionizing electromagnetic radiation, and (3) extant guidelines for limiting exposure of patients and medical personnel to the fields produced by NMR devices. On the basis of information available at the present time, it is concluded that the fields associated with the current generation of NMR devices do not pose a significant health risk in themselves. However, rigorous guidelines must be followed to avoid the physical interaction of these fields with metallic implants and medical electronic devices. 476 refs., 5 figs., 2 tabs.

Biological effects and physical safety aspects of NMR imaging and in vivo spectroscopy

International Nuclear Information System (INIS)

Tenforde, T.S.; Budinger, T.F.

1985-08-01

An assessment is made of the biological effects and physical hazards of static and time-varying fields associated with the NMR devices that are being used for clinical imaging and in vivo spectroscopy. A summary is given of the current state of knowledge concerning the mechanisms of interaction and the bioeffects of these fields. Additional topics that are discussed include: (1) physical effects on pacemakers and metallic implants such as aneurysm clips, (2) human health studies related to the effects of exposure to nonionizing electromagnetic radiation, and (3) extant guidelines for limiting exposure of patients and medical personnel to the fields produced by NMR devices. On the basis of information available at the present time, it is concluded that the fields associated with the current generation of NMR devices do not pose a significant health risk in themselves. However, rigorous guidelines must be followed to avoid the physical interaction of these fields with metallic implants and medical electronic devices. 476 refs., 5 figs., 2 tabs

Atomic molecular and optical physics

International Nuclear Information System (INIS)

Anon.

1986-01-01

Laser-assisted manufacturing and fiber-optics communications are but two of the products of atomic, molecular, and optical physics, (AMO) research. AMO physics provides theoretical and experimental methods and essential data to neighboring areas of science such as chemistry, astrophysics, condensed-matter physics, plasma physics, surface science, biology, and medicine. This book addresses advances in atomic, molecular, and optical fields and provides recommendations for further research. It also looks at scientific applications in national security, manufacturing, medicine, and other fields

Mixed-Methods Design in Biology Education Research: Approach and Uses

Science.gov (United States)

Warfa, Abdi-Rizak M.

2016-01-01

Educational research often requires mixing different research methodologies to strengthen findings, better contextualize or explain results, or minimize the weaknesses of a single method. This article provides practical guidelines on how to conduct such research in biology education, with a focus on mixed-methods research (MMR) that uses both…

A discussion of molecular biology methods for protein engineering

CSIR Research Space (South Africa)

Zawaira, A

2011-09-01

Full Text Available A number of molecular biology techniques are available to generate variants from a particular start gene for eventual protein expression. The authors discuss the basic principles of these methods in a repertoire that may be used to achieve...

Evaluation of gene association methods for coexpression network construction and biological knowledge discovery.

Directory of Open Access Journals (Sweden)

Sapna Kumari

Full Text Available BACKGROUND: Constructing coexpression networks and performing network analysis using large-scale gene expression data sets is an effective way to uncover new biological knowledge; however, the methods used for gene association in constructing these coexpression networks have not been thoroughly evaluated. Since different methods lead to structurally different coexpression networks and provide different information, selecting the optimal gene association method is critical. METHODS AND RESULTS: In this study, we compared eight gene association methods - Spearman rank correlation, Weighted Rank Correlation, Kendall, Hoeffding's D measure, Theil-Sen, Rank Theil-Sen, Distance Covariance, and Pearson - and focused on their true knowledge discovery rates in associating pathway genes and construction coordination networks of regulatory genes. We also examined the behaviors of different methods to microarray data with different properties, and whether the biological processes affect the efficiency of different methods. CONCLUSIONS: We found that the Spearman, Hoeffding and Kendall methods are effective in identifying coexpressed pathway genes, whereas the Theil-sen, Rank Theil-Sen, Spearman, and Weighted Rank methods perform well in identifying coordinated transcription factors that control the same biological processes and traits. Surprisingly, the widely used Pearson method is generally less efficient, and so is the Distance Covariance method that can find gene pairs of multiple relationships. Some analyses we did clearly show Pearson and Distance Covariance methods have distinct behaviors as compared to all other six methods. The efficiencies of different methods vary with the data properties to some degree and are largely contingent upon the biological processes, which necessitates the pre-analysis to identify the best performing method for gene association and coexpression network construction.

Promoting convergence: The integrated graduate program in physical and engineering biology at Yale University, a new model for graduate education.

Science.gov (United States)

Noble, Dorottya B; Mochrie, Simon G J; O'Hern, Corey S; Pollard, Thomas D; Regan, Lynne

2016-11-12

In 2008, we established the Integrated Graduate Program in Physical and Engineering Biology (IGPPEB) at Yale University. Our goal was to create a comprehensive graduate program to train a new generation of scientists who possess a sophisticated understanding of biology and who are capable of applying physical and quantitative methodologies to solve biological problems. Here we describe the framework of the training program, report on its effectiveness, and also share the insights we gained during its development and implementation. The program features co-teaching by faculty with complementary specializations, student peer learning, and novel hands-on courses that facilitate the seamless blending of interdisciplinary research and teaching. It also incorporates enrichment activities to improve communication skills, engage students in science outreach, and foster a cohesive program cohort, all of which promote the development of transferable skills applicable in a variety of careers. The curriculum of the graduate program is integrated with the curricular requirements of several Ph.D.-granting home programs in the physical, engineering, and biological sciences. Moreover, the wide-ranging recruiting activities of the IGPPEB serve to enhance the quality and diversity of students entering graduate school at Yale. We also discuss some of the challenges we encountered in establishing and optimizing the program, and describe the institution-level changes that were catalyzed by the introduction of the new graduate program. The goal of this article is to serve as both an inspiration and as a practical "how to" manual for those who seek to establish similar programs at their own institutions. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(6):537-549, 2016. © 2016 The Authors Biochemistry and Molecular Biology Education published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology.

Physical-chemical property based sequence motifs and methods regarding same

Science.gov (United States)

Braun, Werner [Friendswood, TX; Mathura, Venkatarajan S [Sarasota, FL; Schein, Catherine H [Friendswood, TX

2008-09-09

A data analysis system, program, and/or method, e.g., a data mining/data exploration method, using physical-chemical property motifs. For example, a sequence database may be searched for identifying segments thereof having physical-chemical properties similar to the physical-chemical property motifs.

Methods of Model Reduction for Large-Scale Biological Systems: A Survey of Current Methods and Trends.

Science.gov (United States)

Snowden, Thomas J; van der Graaf, Piet H; Tindall, Marcus J

2017-07-01

Complex models of biochemical reaction systems have become increasingly common in the systems biology literature. The complexity of such models can present a number of obstacles for their practical use, often making problems difficult to intuit or computationally intractable. Methods of model reduction can be employed to alleviate the issue of complexity by seeking to eliminate those portions of a reaction network that have little or no effect upon the outcomes of interest, hence yielding simplified systems that retain an accurate predictive capacity. This review paper seeks to provide a brief overview of a range of such methods and their application in the context of biochemical reaction network models. To achieve this, we provide a brief mathematical account of the main methods including timescale exploitation approaches, reduction via sensitivity analysis, optimisation methods, lumping, and singular value decomposition-based approaches. Methods are reviewed in the context of large-scale systems biology type models, and future areas of research are briefly discussed.

Health physics

International Nuclear Information System (INIS)

Poston, J.W.

1974-01-01

In a series of eight lectures the following topics are dealt with: 1) interaction of radiation with matter; 2) radiation quantities and units; 3) the physical basis of radiation dosimetry; 4) detection and measurement of radiation; 5) mixed radiation dosimetry; 6) special methods in radiation dosimetry; 7) dose from electrons and beta rays; and 8) introduction to radiation biology

Separation and sorting of cells in microsystems using physical principles

Science.gov (United States)

Lee, Gi-Hun; Kim, Sung-Hwan; Ahn, Kihoon; Lee, Sang-Hoon; Park, Joong Yull

2016-01-01

In the last decade, microfabrication techniques have been combined with microfluidics and applied to cell biology. Utilizing such new techniques, various cell studies have been performed for the research of stem cells, immune cells, cancer, neurons, etc. Among the various biological applications of microtechnology-based platforms, cell separation technology has been highly regarded in biological and clinical fields for sorting different types of cells, finding circulating tumor cells (CTCs), and blood cell separation, amongst other things. Many cell separation methods have been created using various physical principles. Representatively, these include hydrodynamic, acoustic, dielectrophoretic, magnetic, optical, and filtering methods. In this review, each of these methods will be introduced, and their physical principles and sample applications described. Each physical principle has its own advantages and disadvantages. The engineers who design the systems and the biologists who use them should understand the pros and cons of each method or principle, to broaden the use of microsystems for cell separation. Continuous development of microsystems for cell separation will lead to new opportunities for diagnosing CTCs and cancer metastasis, as well as other elements in the bloodstream.

Correlating Multimodal Physical Sensor Information with Biological Analysis in Ultra Endurance Cycling

Directory of Open Access Journals (Sweden)

Giles D.Warrington

2010-07-01

Full Text Available The sporting domain has traditionally been used as a testing ground for new technologies which subsequently make their way into the public domain. This includes sensors. In this article a range of physical and biological sensors deployed in a 64 hour ultra-endurance non-stop cycling race are described. A novel algorithm to estimate the energy expenditure while cycling and resting during the event are outlined. Initial analysis in this noisy domain of “sensors in the field” are very encouraging and represent a first with respect to cycling.

An overview of bioinformatics methods for modeling biological pathways in yeast.

Science.gov (United States)

Hou, Jie; Acharya, Lipi; Zhu, Dongxiao; Cheng, Jianlin

2016-03-01

The advent of high-throughput genomics techniques, along with the completion of genome sequencing projects, identification of protein-protein interactions and reconstruction of genome-scale pathways, has accelerated the development of systems biology research in the yeast organism Saccharomyces cerevisiae In particular, discovery of biological pathways in yeast has become an important forefront in systems biology, which aims to understand the interactions among molecules within a cell leading to certain cellular processes in response to a specific environment. While the existing theoretical and experimental approaches enable the investigation of well-known pathways involved in metabolism, gene regulation and signal transduction, bioinformatics methods offer new insights into computational modeling of biological pathways. A wide range of computational approaches has been proposed in the past for reconstructing biological pathways from high-throughput datasets. Here we review selected bioinformatics approaches for modeling biological pathways inS. cerevisiae, including metabolic pathways, gene-regulatory pathways and signaling pathways. We start with reviewing the research on biological pathways followed by discussing key biological databases. In addition, several representative computational approaches for modeling biological pathways in yeast are discussed. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Biosocial Conservation: Integrating Biological and Ethnographic Methods to Study Human-Primate Interactions.

Science.gov (United States)

Setchell, Joanna M; Fairet, Emilie; Shutt, Kathryn; Waters, Siân; Bell, Sandra

2017-01-01

Biodiversity conservation is one of the grand challenges facing society. Many people interested in biodiversity conservation have a background in wildlife biology. However, the diverse social, cultural, political, and historical factors that influence the lives of people and wildlife can be investigated fully only by incorporating social science methods, ideally within an interdisciplinary framework. Cultural hierarchies of knowledge and the hegemony of the natural sciences create a barrier to interdisciplinary understandings. Here, we review three different projects that confront this difficulty, integrating biological and ethnographic methods to study conservation problems. The first project involved wildlife foraging on crops around a newly established national park in Gabon. Biological methods revealed the extent of crop loss, the species responsible, and an effect of field isolation, while ethnography revealed institutional and social vulnerability to foraging wildlife. The second project concerned great ape tourism in the Central African Republic. Biological methods revealed that gorilla tourism poses risks to gorillas, while ethnography revealed why people seek close proximity to gorillas. The third project focused on humans and other primates living alongside one another in Morocco. Incorporating shepherds in the coproduction of ecological knowledge about primates built trust and altered attitudes to the primates. These three case studies demonstrate how the integration of biological and social methods can help us to understand the sustainability of human-wildlife interactions, and thus promote coexistence. In each case, an integrated biosocial approach incorporating ethnographic data produced results that would not otherwise have come to light. Research that transcends conventional academic boundaries requires the openness and flexibility to move beyond one's comfort zone to understand and acknowledge the legitimacy of "other" kinds of knowledge. It is

Multi-Level iterative methods in computational plasma physics

International Nuclear Information System (INIS)

Knoll, D.A.; Barnes, D.C.; Brackbill, J.U.; Chacon, L.; Lapenta, G.

1999-01-01

Plasma physics phenomena occur on a wide range of spatial scales and on a wide range of time scales. When attempting to model plasma physics problems numerically the authors are inevitably faced with the need for both fine spatial resolution (fine grids) and implicit time integration methods. Fine grids can tax the efficiency of iterative methods and large time steps can challenge the robustness of iterative methods. To meet these challenges they are developing a hybrid approach where multigrid methods are used as preconditioners to Krylov subspace based iterative methods such as conjugate gradients or GMRES. For nonlinear problems they apply multigrid preconditioning to a matrix-few Newton-GMRES method. Results are presented for application of these multilevel iterative methods to the field solves in implicit moment method PIC, multidimensional nonlinear Fokker-Planck problems, and their initial efforts in particle MHD

Method of 10B determination in biological specimens

International Nuclear Information System (INIS)

Nikitina, R.G.; Frolova, E.I.

1981-01-01

The paper is concerned with the methods of 10 B determination in biological specimens (blood, skin and tissues of rats). On the basis of investigations conducted there have been proposed films based on cellulose triacetate with optimal characteristics in terms of their possible utilization as solid detectors to record α-particles and recoil nuclei. The conditions of film staining are also discussed

A method for three-dimensional quantitative observation of the microstructure of biological samples

Science.gov (United States)

Wang, Pengfei; Chen, Dieyan; Ma, Wanyun; Wu, Hongxin; Ji, Liang; Sun, Jialin; Lv, Danyu; Zhang, Lu; Li, Ying; Tian, Ning; Zheng, Jinggao; Zhao, Fengying

2009-07-01

Contemporary biology has developed into the era of cell biology and molecular biology, and people try to study the mechanism of all kinds of biological phenomena at the microcosmic level now. Accurate description of the microstructure of biological samples is exigent need from many biomedical experiments. This paper introduces a method for 3-dimensional quantitative observation on the microstructure of vital biological samples based on two photon laser scanning microscopy (TPLSM). TPLSM is a novel kind of fluorescence microscopy, which has excellence in its low optical damage, high resolution, deep penetration depth and suitability for 3-dimensional (3D) imaging. Fluorescent stained samples were observed by TPLSM, and afterward the original shapes of them were obtained through 3D image reconstruction. The spatial distribution of all objects in samples as well as their volumes could be derived by image segmentation and mathematic calculation. Thus the 3-dimensionally and quantitatively depicted microstructure of the samples was finally derived. We applied this method to quantitative analysis of the spatial distribution of chromosomes in meiotic mouse oocytes at metaphase, and wonderful results came out last.

The human heart and the circulatory system as an interesting interdisciplinary topic in lessons of physics and biology

International Nuclear Information System (INIS)

Volná, M; Látal, F; Kubínek, R; Richterek, L

2014-01-01

Many topics which are closely related can be found in the national curriculum of the Czech Republic for physics and biology. One of them is the heart and the circulatory system in the human body. This topic was examined cross curriculum, a teaching module was created and the topic was chosen for our research. The task was to determine if the students of bachelor study are aware of connections between physics and biology within this topic and whether we can help them effectively to describe the corresponding physics phenomena in the human body connected, for example, with a heart attack or with the measurement of blood pressure. In this paper, the heart and the circulatory system are presented as suitable topics for an interdisciplinary teaching module which includes both theoretical and experimental parts. The module was evaluated by a group of first-year undergraduate students of physics at the Faculty of Science, Palacký University. The acquired knowledge was compared with another control group through a test. The highest efficiency of the module was evaluated on the basis of questions that covered the calculation problems. (paper)

Progress report, Biology and Health Physics Division, January 1 to March 31, 1978

International Nuclear Information System (INIS)

Progress of work in Biology and Health Physics Division is reported for first quarter 1978. Measurements of liquid and plastic scintillator responses over a wide range of gamma-ray energies and calculations of the shape of the Compton electron distribution have been made for different scintillator sizes. Other work performed in health physics included determination of errors involved in accurate determination of dose-equivalents resulting from tritium ingestion, and development of radiation monitors and techniques for using them to best advantage. A wide range of environmental studies were underway during the quarter, notably 14 C/ 12 C ratio measurement using an accelerator-spectrometer and contiuing studies of the beneficial uses of thermal effluents. Development of computer linkage techniques for medical records continued. Practical applications of the approach include linkage of personal exposure histories with death records pertaining to the exposed individuals. Work in the Biology Branch has continued to focus upon the effects of radiation on a variety of living organisms, ranging from bacterial viruses to humans. The principal sensitive target for long-term biological effects of radiation on all living organisms is DNA. The chemical nature of the damage caused in DNA by radiation and the response of cells to this damage is being studied by a variety of biochemical and genetic techniques. A review of literature on the causes of cancer in humans has continued. If effects are linearly related to total dose, as is normally assumed for purposes of radiation protection, then the total number of fatal cancers predicted to arise from the use of nuclear power in the future should be about 100 times less than the number induced by urban air pollution resulting from the combustion of coal and oil to produce the same amount of electricity. (OST)

Structures linking physical and biological processes in headwater streams of the Maybeso watershed, Southeast Alaska

Science.gov (United States)

Mason D. Bryant; Takashi Gomi; Jack J. Piccolo

2007-01-01

We focus on headwater streams originating in the mountainous terrain of northern temperate rain forests. These streams rapidly descend from gradients greater than 20% to less than 5% in U-shaped glacial valleys. We use a set of studies on headwater streams in southeast Alaska to define headwater stream catchments, link physical and biological processes, and describe...

Mathematical methods in physics distributions, Hilbert space operators, variational methods, and applications in quantum physics

CERN Document Server

Blanchard, Philippe

2015-01-01

The second edition of this textbook presents the basic mathematical knowledge and skills that are needed for courses on modern theoretical physics, such as those on quantum mechanics, classical and quantum field theory, and related areas.  The authors stress that learning mathematical physics is not a passive process and include numerous detailed proofs, examples, and over 200 exercises, as well as hints linking mathematical concepts and results to the relevant physical concepts and theories.  All of the material from the first edition has been updated, and five new chapters have been added on such topics as distributions, Hilbert space operators, and variational methods.   The text is divided into three main parts. Part I is a brief introduction to distribution theory, in which elements from the theories of ultradistributions and hyperfunctions are considered in addition to some deeper results for Schwartz distributions, thus providing a comprehensive introduction to the theory of generalized functions. P...

Computer programs of information processing of nuclear physical methods as a demonstration material in studying nuclear physics and numerical methods

Science.gov (United States)

Bateev, A. B.; Filippov, V. P.

2017-01-01

The principle possibility of using computer program Univem MS for Mössbauer spectra fitting as a demonstration material at studying such disciplines as atomic and nuclear physics and numerical methods by students is shown in the article. This program is associated with nuclear-physical parameters such as isomer (or chemical) shift of nuclear energy level, interaction of nuclear quadrupole moment with electric field and of magnetic moment with surrounded magnetic field. The basic processing algorithm in such programs is the Least Square Method. The deviation of values of experimental points on spectra from the value of theoretical dependence is defined on concrete examples. This value is characterized in numerical methods as mean square deviation. The shape of theoretical lines in the program is defined by Gaussian and Lorentzian distributions. The visualization of the studied material on atomic and nuclear physics can be improved by similar programs of the Mössbauer spectroscopy, X-ray Fluorescence Analyzer or X-ray diffraction analysis.

From the Physical World to the Biological Universe: Historical Developments Underlying SETI

Science.gov (United States)

Dick, Steven J.

More than thirty years ago the French historian of science Alexandre Koyré (1957) wrote his classic volume, From the Closed World to the Infinite Universe, in which he argued that a fundamental shift in world view had taken place in 17th century cosmology. Between Nicholas of Cusa in the fifteenth century and Newton and Leibniz in the seventeenth, he found that the very terms in which humans thought about their universe had changed. These changes he characterized broadly as the destruction of the closed finite cosmos and the geometrization of space. The occasion of the Third International Bioastronomy Symposium in France is an especially appropriate time to argue that the SETI endeavor represents a test for a similar fundamental shift in cosmological world view, from the physical world to the biological universe. I define the biological universe, equivalent to what I have called before the biophysical cosmology (Dick, 1989), as the scientific world view which holds that life is widespread throughout the universe. In this case the biological universe does not necessarily supersede the physical universe, but a universe filled with life would certainly fundamentally alter our attitude toward the universe, and our place in it. Although Koyré mentioned life beyond the Earth as an adjunct to the revolution from the closed world to the infinite universe, only in the 1980s has the history of science begun to give full treatment to the subject. What follows is meant to be a contribution to that ongoing endeavor to understand where the extraterrestrial life debate fits in the history of science. The modern era in the extraterrestrial life debate is normally dated from Cocconi and Morrison's paper in 1959, and though one can always find precursors, this in my view is a valid perception. Cocconi and Morrison gave definite form to SETI, Frank Drake independently first carried out the experiment, a network of interested scientists began to form and met in Green Bank in

Mathematical methods in engineering and physics

CERN Document Server

Felder, Gary N

2016-01-01

This text is intended for the undergraduate course in math methods, with an audience of physics and engineering majors. As a required course in most departments, the text relies heavily on explained examples, real-world applications and student engagement. Supporting the use of active learning, a strong focus is placed upon physical motivation combined with a versatile coverage of topics that can be used as a reference after students complete the course. Each chapter begins with an overview that includes a list of prerequisite knowledge, a list of skills that will be covered in the chapter, and an outline of the sections. Next comes the motivating exercise, which steps the students through a real-world physical problem that requires the techniques taught in each chapter.

Physics must join with biology in better assessing risk from low-dose irradiation

International Nuclear Information System (INIS)

Feinendegen, L. E.; Neumann, R. D.

2005-01-01

This review summarises the complex response of mammalian cells and tissues to low doses of ionising radiation. This thesis encompasses induction of DNA damage, and adaptive protection against both renewed damage and against propagation of damage from the basic level of biological organisation to the clinical expression of detriment. The induction of DNA damage at low radiation doses apparently is proportional to absorbed dose at the physical/chemical level. However, any propagation of such damage to higher levels of biological organisation inherently follows a sigmoid function. Moreover, low-dose-induced inhibition of damage propagation is not linear, but instead follows a dose-effect function typical for adaptive protection, after an initial rapid rise it disappears at doses higher than ∼0.1-0.2 Gy to cells. The particular biological response duality at low radiation doses precludes the validity of the linear-no-threshold hypothesis in the attempt to relate absorbed dose to cancer. In fact, theory and observation support not only a lower cancer incidence than expected from the linear-no-threshold hypothesis, but also a reduction of spontaneously occurring cancer, a hormetic response, in the healthy individual. (authors)

REVIEW OF SELECTED BIOLOGICAL METHODS OF ASSESSING THE QUALITY OF NATURAL ENVIRONMENT

Directory of Open Access Journals (Sweden)

Monika Beata Jakubus

2015-04-01

Full Text Available The xenobiotics introduced into the environment are the effect of human activities. It is especially soil contamination that leads to degradation of soils, which may finally be referred to the biological imbalance of the ecosystem. Normally chemical methods are used for the assessment of soil’s quality. Unfortunately, they are not always quick and inexpensive. Therefore, the practice and the science at environmental monitoring more frequently employ biological methods. Most of them meet the above mentioned conditions and become a supplement of routine laboratory practices. This publication shows an overview of selected common biological methods used to estimate the quality of the environment. The first part of the paper presents biomonitoring as a first step of environmental control which relies on the observation of indicator organisms. The next section was dedicated to the bioassays, indicating the greater or lesser practical applications confirmed by literature on the subject. Particular attention has been focused on phytotests and the tests based on the invertebrates.

Interpretation of biological and mechanical variations between the Lowry versus Bradford method for protein quantification

OpenAIRE

Tzong-Shi Lu; Szu-Yu Yiao; Kenneth Lim; Roderick V. Jensen; Li-Li Hsiao

2010-01-01

Background: The identification of differences in protein expression resulting from methodical variations is an essential component to the interpretation of true, biologically significant results. Aims: We used the Lowry and Bradford methods- two most commonly used methods for protein quantification, to assess whether differential protein expressions are a result of true biological or methodical variations. Material & Methods: Differential protein expression patterns was assessed by western bl...

Analysis of MIR-18 results for physical and biological dosimetry: radiation shielding effectiveness in LEO

International Nuclear Information System (INIS)

Cucinotta, F.A.; Wilson, J.W.; Williams, J.R.; Dicello, J.F.

2000-01-01

We compare models of radiation transport and biological response to physical and biological dosimetry results from astronauts on the Mir space station. Transport models are shown to be in good agreement with physical measurements and indicate that the ratio of equivalent dose from the Galactic Cosmic Rays (GCR) to protons is about 3/2:1 and that this ratio will increase for exposures to internal organs. Two biological response models are used to compare to the Mir biodosimetry for chromosome aberration in lymphocyte cells; a track-structure model and the linear-quadratic model with linear energy transfer (LET) dependent weighting coefficients. These models are fit to in vitro data for aberration formation in human lymphocytes by photons and charged particles. Both models are found to be in reasonable agreement with data for aberrations in lymphocytes of Mir crew members: however there are differences between the use of LET dependent weighting factors and track structure models for assigning radiation quality factors. The major difference in the models is the increased effectiveness predicted by the track model for low charge and energy ions with LET near 10 keV/μm. The results of our calculations indicate that aluminum shielding, although providing important mitigation of the effects of trapped radiation, provides no protective effect from the galactic cosmic rays (GCR) in low-earth orbit (LEO) using either equivalent dose or the number of chromosome aberrations as a measure until about 100 g/cm 2 of material is used

The method of sections in molecular physics

International Nuclear Information System (INIS)

Natarajan, P.; Zygelman, B.

1993-01-01

In the standard Born-Oppenheimer theory the nuclear wave-function for a bound, rotating, di-atom system is described by the Wigner functions. Unlike the spherical harmonics, the Wigner functions exhibit cusp singularities at the poles of the space-fixed coordinate system. These singularities are identical to the ones encountered in the quantum mechanics treatment of a charged particle under the influence of a magnetic monopole. In the latter case the method of sectional was introduced to eliminate the singularities. The method of sections was also introduced in molecular physics. We discuss here, in detail, their properties and advantage of using this construction in molecular physics

Physical, chemical, and biological data collected in Mobile Bay, Alabama in May 1989-December 1999 (NODC Accession 0116496)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains physical, chemical, and biological data collected during ten years of near-monthly shipboard surveys carried out in Mobile Bay between May 1989...

The effect of shape on drag: a physics exercise inspired by biology

Science.gov (United States)

Fingerut, Jonathan; Johnson, Nicholas; Mongeau, Eric; Habdas, Piotr

2017-07-01

As part of a biomechanics course aimed at upper-division biology and physics majors, but applicable to a range of student learning levels, this laboratory exercise provides an insight into the effect of shape on hydrodynamic performance, as well an introduction to computer aided design (CAD) and 3D printing. Students use hydrodynamic modeling software and simple CAD programs to design a shape with the least amount of drag based on strategies gleaned from the study of natural forms. Students then print the shapes using a 3D printer and test their shapes against their classmates in a friendly competition. From this exercise, students gain a more intuitive sense of the challenges that organisms face when moving through fluid environments, the physical phenomena involved in moving through fluids at high Reynolds numbers and observe how and why certain morphologies, such as streamlining, are common answers to the challenge of swimming at high speeds.

Modern methodic of power cardio training in students’ physical education

Directory of Open Access Journals (Sweden)

A.Yu. Osipov

2016-12-01

Full Text Available Purpose: significant increase of students’ physical condition and health level at the account of application of modern power cardio training methodic. Material: 120 students (60 boys and 60 girls participated in the research. The age of the tested was 19 years. The research took one year. We used methodic of power and functional impact on trainees’ organism (HOT IRON. Such methodic is some systems of physical exercises with weights (mini-barbells, to be fulfilled under accompaniment of specially selected music. Results: we showed advantages of power-cardio and fitness trainings in students’ health improvement and in elimination obesity. Control tests showed experimental group students achieved confidently higher physical indicators. Boys demonstrated increase of physical strength and general endurance indicators. Girls had confidently better indicators of physical strength, flexibility and general endurance. Increase of control group students’ body mass can be explained by students’ insufficient physical activity at trainings, conducted as per traditional program. Conclusions: students’ trainings by power-cardio methodic with application HOT IRON exercises facilitate development the following physical qualities: strength and endurance in boys and strength, flexibility and endurance in girls. Besides, it was found that such systems of exercises facilitate normalization of boys’ body mass and correction of girls’ constitution.

Highly cited German research contributions to the fields of radiation oncology, biology, and physics. Focus on collaboration and diversity

Energy Technology Data Exchange (ETDEWEB)

Nieder, C. [Nordland Hospital, Bodoe (Norway). Dept. of Oncology and Palliative Medicine; Tromsoe Univ. (Norway). Inst. of Clinical Medicine

2012-10-15

Background and purpose: Tight budgets and increasing competition for research funding pose challenges for highly specialized medical disciplines such as radiation oncology. Therefore, a systematic review was performed of successfully completed research that had a high impact on clinical practice. These data might be helpful when preparing new projects. Methods: Different measures of impact, visibility, and quality of published research are available, each with its own pros and cons. For this study, the article citation rate was chosen (minimum 15 citations per year on average). Highly cited German contributions to the fields of radiation oncology, biology, and physics (published between 1990 and 2010) were identified from the Scopus database. Results: Between 1990 and 2010, 106 articles published in 44 scientific journals met the citation requirement. The median average of yearly citations was 21 (maximum 167, minimum 15). All articles with {>=} 40 citations per year were published between 2003 and 2009, consistent with the assumption that the citation rate gradually increases for up to 2 years after publication. Most citations per year were recorded for meta-analyses and randomized phase III trials, which typically were performed by collaborative groups. Conclusion: A large variety of clinical radiotherapy, biology, and physics topics achieved high numbers of citations. However, areas such as quality of life and side effects, palliative radiotherapy, and radiotherapy for nonmalignant disorders were underrepresented. Efforts to increase their visibility might be warranted. (orig.)

Highly cited German research contributions to the fields of radiation oncology, biology, and physics. Focus on collaboration and diversity

International Nuclear Information System (INIS)

Nieder, C.; Tromsoe Univ.

2012-01-01

Background and purpose: Tight budgets and increasing competition for research funding pose challenges for highly specialized medical disciplines such as radiation oncology. Therefore, a systematic review was performed of successfully completed research that had a high impact on clinical practice. These data might be helpful when preparing new projects. Methods: Different measures of impact, visibility, and quality of published research are available, each with its own pros and cons. For this study, the article citation rate was chosen (minimum 15 citations per year on average). Highly cited German contributions to the fields of radiation oncology, biology, and physics (published between 1990 and 2010) were identified from the Scopus database. Results: Between 1990 and 2010, 106 articles published in 44 scientific journals met the citation requirement. The median average of yearly citations was 21 (maximum 167, minimum 15). All articles with ≥ 40 citations per year were published between 2003 and 2009, consistent with the assumption that the citation rate gradually increases for up to 2 years after publication. Most citations per year were recorded for meta-analyses and randomized phase III trials, which typically were performed by collaborative groups. Conclusion: A large variety of clinical radiotherapy, biology, and physics topics achieved high numbers of citations. However, areas such as quality of life and side effects, palliative radiotherapy, and radiotherapy for nonmalignant disorders were underrepresented. Efforts to increase their visibility might be warranted. (orig.)

Methods of 15N tracer research in biological systems

International Nuclear Information System (INIS)

Hirschberg, K.; Faust, H.

1985-01-01

The application of the stable isotope 15 N is of increasing importance in different scientific disciplines, especially in medicine, agriculture, and the biosciences. The close correlation between the growing interest and improvements of analytical procedures resulted in remarkable advances in the 15 N tracer technique. On the basis of the latest results of 15 N tracer research in life sciences and agriculture methods of 15 N tracer research in biological systems are compiled. The 15 N methodology is considered under three headings: Chemical analysis with a description of methods of sample preparation (including different separation and isolation methods for N-containing substances of biological and agricultural origin) and special procedures converting ammonia to molecular nitrogen. Isotopic analysis with a review on the most important methods of isotopic analysis of nitrogen: mass spectrometry (including the GC-MS technique), emission spectrometry, NMR spectroscopy, and other analytical procedures. 15 N-tracer techniques with a consideration of the role of the isotope dilution analysis as well as different labelling techniques and the mathematical interpretation of tracer data (modelling, N turnover experiments). In these chapters also sources of errors in chemical and isotopic analysis, the accuracy of the different methods and its importance on tracer experiments are discussed. Procedures for micro scale 15 N analysis and aspects of 15 N analysis on the level of natural abundance are considered. Furthermore some remarks on isotope effects in 15 N tracer experiments are made. (author)

The Photo-Physics of Polythiophene Nanoparticles for Biological Applications.

Science.gov (United States)

Bargigia, Ilaria; Zucchetti, Elena; Srimath Kandada, Ajay Ram; Moreira, Miguel; Bossio, Caterina; Wong, Walter; Miranda, Paulo; Decuzzi, Paolo; Soci, Cesare; D'Andrea, Cosimo; Lanzani, Guglielmo

2018-05-01

In this work the photo-physics of poly(3-hexyltiophene) nanoparticles (NPs) is investigated in the context of their biological applications. The NPs made as colloidal suspensions in aqueous buffers present a distinct absorption band in the low energy region. Based on systematic analysis of absorption and transient absorption spectra taken under different pH conditions, this band is associated to charge transfer states generated by the polarization of loosely bound polymer chains and originated from complexes formed with electron withdrawing species. Importantly, the ground state depletion of these states upon photo-excitation is active even in the microsecond timescales, suggesting that they act as precursor states for long-living polarons which could be beneficial for cellular stimulation. Preliminary results of transient absorption microscopy of NPs internalized within the cells reveal the presence of long-living species, further substantiating their relevance in bio-interfaces. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel biological 'twin-father' temporal paradox of General Relativity in a Gödel universe - Where reproductive biology meets theoretical physics.

Science.gov (United States)

Ashrafian, Hutan

2018-03-01

Several temporal paradoxes exist in physics. These include General Relativity's grandfather and ontological paradoxes and Special Relativity's Langevin-Einstein twin-paradox. General relativity paradoxes can exist due to a Gödel universe that follows Gödel's closed timelike curves solution to Einstein's field equations. A novel biological temporal paradox of General Relativity is proposed based on reproductive biology's phenomenon of heteropaternal fecundation. Herein, dizygotic twins from two different fathers are the result of concomitant fertilization during one menstrual cycle. In this case an Oedipus-like individual exposed to a Gödel closed timelike curve would sire a child during his maternal fertilization cycle. As a consequence of heteropaternal superfecundation, he would father his own dizygotic twin and would therefore generate a new class of autofraternal superfecundation, and by doing so creating a 'twin-father' temporal paradox. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using the Case Study Method in Teaching College Physics

Science.gov (United States)

Burko, Lior M.

2016-01-01

The case study teaching method has a long history (starting at least with Socrates) and wide current use in business schools, medical schools, law schools, and a variety of other disciplines. However, relatively little use is made of it in the physical sciences, specifically in physics or astronomy. The case study method should be considered by…

Sensitivity and Uncertainty Analysis of Coupled Reactor Physics Problems : Method Development for Multi-Physics in Reactors

NARCIS (Netherlands)

Perkó, Z.

2015-01-01

This thesis presents novel adjoint and spectral methods for the sensitivity and uncertainty (S&U) analysis of multi-physics problems encountered in the field of reactor physics. The first part focuses on the steady state of reactors and extends the adjoint sensitivity analysis methods well

Computer methods in physics 250 problems with guided solutions

CERN Document Server

Landau, Rubin H

2018-01-01

Our future scientists and professionals must be conversant in computational techniques. In order to facilitate integration of computer methods into existing physics courses, this textbook offers a large number of worked examples and problems with fully guided solutions in Python as well as other languages (Mathematica, Java, C, Fortran, and Maple). It’s also intended as a self-study guide for learning how to use computer methods in physics. The authors include an introductory chapter on numerical tools and indication of computational and physics difficulty level for each problem.

Biological-Physical Coupling in the Gulf of Maine: Satellite and Model Studies of Phytoplankton Variability

Science.gov (United States)

Thomas, Andrew C.; Chai, F.; Townsend, D. W.; Xue, H.

2002-01-01

The goals of this project were to acquire, process, QC, archive and analyze SeaWiFS chlorophyll fields over the Gulf of Maine and Scotia Shelf region. The focus of the analysis effort was to calculate and quantify seasonality and interannual. variability of SeaWiFS-measured phytoplankton biomass in the study area and compare these to physical forcing and hydrography. An additional focus within this effort was on regional differences within the heterogeneous biophysical regions of the Gulf of Maine / Scotia Shelf. Overall goals were approached through the combined use of SeaWiFS and AVHRR data and the development of a coupled biology-physical numerical model.

Application of unsupervised learning methods in high energy physics

Energy Technology Data Exchange (ETDEWEB)

Koevesarki, Peter; Nuncio Quiroz, Adriana Elizabeth; Brock, Ian C. [Physikalisches Institut, Universitaet Bonn, Bonn (Germany)

2011-07-01

High energy physics is a home for a variety of multivariate techniques, mainly due to the fundamentally probabilistic behaviour of nature. These methods generally require training based on some theory, in order to discriminate a known signal from a background. Nevertheless, new physics can show itself in ways that previously no one thought about, and in these cases conventional methods give little or no help. A possible way to discriminate between known processes (like vector bosons or top-quark production) or look for new physics is using unsupervised machine learning to extract the features of the data. A technique was developed, based on the combination of neural networks and the method of principal curves, to find a parametrisation of the non-linear correlations of the data. The feasibility of the method is shown on ATLAS data.

PHYSICAL METHODS IN AGRO-FOOD CHAIN

Directory of Open Access Journals (Sweden)

ANNA ALADJADJIYAN

2009-06-01

Full Text Available Chemical additives (fertilizers and plant protection preparations are largely used for improving the production yield of food produce. Their application often causes the contamination of raw materials for food production, which can be dangerous for the health of consumers. Alternative methods are developed and implemented to improve and ensure the safety of on-farm production. The substitution of chemical fertilizers and soil additives with alternative treatment methods, such as irradiation, ultrasound and the use of electromagnetic energy are discussed. Successful application of physical methods in different stages of food-preparation is recommended.

Emerging concepts for management of river ecosystems and challenges to applied integration of physical and biological sciences in the Pacific Northwest, USA

Science.gov (United States)

Rieman, Bruce; Dunham, Jason B.; Clayton, James

2006-01-01

Integration of biological and physical concepts is necessary to understand and conserve the ecological integrity of river systems. Past attempts at integration have often focused at relatively small scales and on mechanistic models that may not capture the complexity of natural systems leaving substantial uncertainty about ecological responses to management actions. Two solutions have been proposed to guide management in the face of that uncertainty: the use of “natural variability” in key environmental patterns, processes, or disturbance as a reference; and the retention of some areas as essentially unmanaged reserves to conserve and represent as much biological diversity as possible. Both concepts are scale dependent because dominant processes or patterns that might be referenced will change with scale. Context and linkages across scales may be as important in structuring biological systems as conditions within habitats used by individual organisms. Both ideas view the physical environment as a template for expression, maintenance, and evolution of ecological diversity. To conserve or restore a diverse physical template it will be important to recognize the ecologically important differences in physical characteristics and processes among streams or watersheds that we might attempt to mimic in management or represent in conservation or restoration reserves.

Radiation physics, biophysics, and radiation biology. Progress report, December 1, 1985-November 30, 1986

International Nuclear Information System (INIS)

Hall, E.J.

1986-07-01

This is the annual report of the Radiological Research Laboratory of the Department of Radiation Oncology, Columbia University. The bulk of the research of the Laboratory involves basic and fundamental aims, not confined to radiotherapy. Research carried out in the Laboratory covers the determination of microdosimetry quantities, computer simulation of particle tracks, determination of oncogenic transformation, and the transfection of DNA into cells. The Hallmark of the Laboratory is the interaction between physics and biology

The biological and physical role of mulch in the rehabilitation of custed soil in the Sahel

NARCIS (Netherlands)

Mando, A.; Stroosnijder, L.

1999-01-01

During three consecutive years (1993–1995) a split-plot design with three replications was used to study the biological and physical role of mulch in the improvement of crusted soil water balance and its productivity in the north of Burkina Faso. The main treatment was the use of an insecticide, to

Scattering theory in quantum mechanics. Physical principles and mathematical methods

International Nuclear Information System (INIS)

Amrein, W.O.; Jauch, J.M.; Sinha, K.B.

1977-01-01

A contemporary approach is given to the classical topics of physics. The purpose is to explain the basic physical concepts of quantum scattering theory, to develop the necessary mathematical tools for their description, to display the interrelation between the three methods (the Schroedinger equation solutions, stationary scattering theory, and time dependence) to derive the properties of various quantities of physical interest with mathematically rigorous methods

Radiation physics, biophysics, and radiation biology. Final report, October 1, 1971--September 30, 1977

International Nuclear Information System (INIS)

Rossi, H.H.; Hall, E.J.

1978-02-01

Research under Contract EY-76-C-02-3243 has been carried out in the area of Radiation Physics, Biophysics and Radiation Biology. During the period of this contract the major accomplishments include, in Physics, the refinement of tissue equivalent dosimetry, the formulation of the concepts of microdosimetry, the development of apparatus used in microdosimetry, and the development of ionization chambers with internal gas multiplication. Principal contributions in Radiobiology have included the determination of RBE and OER as a function of neutron energy, the study of combined effects of radiation and a variety of other agents, and the investigation of the transformation of cells in tissue culture. Theoretical research centered around the development of the theoretical framework of microdosimetry and the establishment of the Theory of Dual Radiation Action. In a cooperative effort with Brookhaven National Laboratory, a major accelerator facility dedicated exclusively to Radiobiology and Radiation Physics, has been developed. Members of the laboratory have performed extensive service to national and international organizations

Biological dosimetry, scopes and limitations

International Nuclear Information System (INIS)

Guerrero C, C.; Brena V, M.

1999-01-01

The analysis of the aberrations in chromosomes is an alternative to establish the exposure dose to the radiation, when the information provided by the traditional physical methods is insufficient. There are diverse causes by which it can reached to apply an alternative system, such is the case of exposures of another persons to the management of radiation sources, which not carry physical dosemeter. Contrary case is to the occupational exposure personnel (OEP), what must to utilize some system for determining the exposure dose, even so can be needed the case for more information. In any case, the cells from the affected person are the alternative without the biological system be overlap to the physical, it is complementary. (Author)

Method and apparatus to image biological interactions in plants

Science.gov (United States)

Weisenberger, Andrew; Bonito, Gregory M.; Reid, Chantal D.; Smith, Mark Frederick

2015-12-22

A method to dynamically image the actual translocation of molecular compounds of interest in a plant root, root system, and rhizosphere without disturbing the root or the soil. The technique makes use of radioactive isotopes as tracers to label molecules of interest and to image their distribution in the plant and/or soil. The method allows for the study and imaging of various biological and biochemical interactions in the rhizosphere of a plant, including, but not limited to, mycorrhizal associations in such regions.

Electron spin interactions in chemistry and biology fundamentals, methods, reactions mechanisms, magnetic phenomena, structure investigation

CERN Document Server

Likhtenshtein, Gertz

2016-01-01

This book presents the versatile and pivotal role of electron spin interactions in nature. It provides the background, methodologies and tools for basic areas related to spin interactions, such as spin chemistry and biology, electron transfer, light energy conversion, photochemistry, radical reactions, magneto-chemistry and magneto-biology. The book also includes an overview of designing advanced magnetic materials, optical and spintronic devices and photo catalysts. This monograph appeals to scientists and graduate students working in the areas related to spin interactions physics, biophysics, chemistry and chemical engineering.

Quality control of X-ray irradiator by biological markers

International Nuclear Information System (INIS)

Miura, Miwa; Lukmanul Hakkim, F.; Yoshida, Masahiro; Matsuda, Naoki; Morita, Naoko

2011-01-01

The exposure of animals or cultured cells to radiation is the essential and common step in experimental researches to elucidate biological effects of radiation. When an X-ray generator is used as a radiation source, physical parameters including dose, dose rate, and the energy spectrum of X-ray play crucial roles in biological outcome. Therefore, those parameters are the important points to be checked in quality control and to be carefully considered in advance to the irradiation to obtain the accurate and reproductive results. Here we measured radiation dose emitted from the X-ray irradiator for research purposes by using clonogenic survival of cultured mammalian cells as a biological marker in parallel with physical dosimetry. The results drawn from both methods exhibited good consistency in the dose distribution on the irradiation stage. Furthermore, the close relationship was observed between cell survival and the photon energy spectrum by using different filter components. These results suggest that biological dosimetry is applicable to quality control of X-ray irradiator in adjunct to physical dosimetry and that it possibly helps better understanding of the optimal irradiating condition by X-ray users in life-science field. (author)

Biological physics and synchrotron radiation

International Nuclear Information System (INIS)

Filhol, J.M.; Chavanne, J.; Weckert, E.

2001-01-01

This conference deals with the applications of synchrotron radiation to current problems in biology and medicine. Seven sessions take stock on the subject: sources and detectors; inelastic scattering and dynamics; muscle diffraction; reaction mechanisms; macromolecular assemblies; medical applications; imaging and spectroscopy. The document presents the papers abstracts. (A.L.B.)

Biological physics and synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Filhol, J M; Chavanne, J [European Synchrotron Radiation Facility, 38 - Grenoble (France); Weckert, E [Hasylab at Desy, Hamburg (Germany); and others

2001-07-01

This conference deals with the applications of synchrotron radiation to current problems in biology and medicine. Seven sessions take stock on the subject: sources and detectors; inelastic scattering and dynamics; muscle diffraction; reaction mechanisms; macromolecular assemblies; medical applications; imaging and spectroscopy. The document presents the papers abstracts. (A.L.B.)

Geometric Methods in Physics : XXXII Workshop

CERN Document Server

Bieliavsky, Pierre; Odesskii, Alexander; Odzijewicz, Anatol; Schlichenmaier, Martin; Voronov, Theodore; Geometric Methods in Physics

2014-01-01

The Białowieża Workshops on Geometric Methods in Physics, which are hosted in the unique setting of the Białowieża natural forest in Poland, are among the most important meetings in the field. Every year some 80 to 100 participants from both the mathematics and physics world join to discuss new developments and to exchange ideas. The current volume was produced on the occasion of the 32nd meeting in 2013. It is now becoming a tradition that the Workshop is followed by a School on Geometry and Physics, which consists of advanced lectures for graduate students and young researchers. Selected speakers at the 2013 Workshop were asked to contribute to this book, and their work was supplemented by additional review articles. The selection shows that, despite its now long tradition, the workshop remains at the cutting edge of research. The 2013 Workshop also celebrated the 75th birthday of Daniel Sternheimer, and on this occasion the discussion mainly focused on his contributions to mathematical physics such as ...

Essential Concepts and Underlying Theories from Physics, Chemistry, and Mathematics for "Biochemistry and Molecular Biology" Majors

Science.gov (United States)

Wright, Ann; Provost, Joseph; Roecklein-Canfield, Jennifer A.; Bell, Ellis

2013-01-01

Over the past two years, through an NSF RCN UBE grant, the ASBMB has held regional workshops for faculty members from around the country. The workshops have focused on developing lists of Core Principles or Foundational Concepts in Biochemistry and Molecular Biology, a list of foundational skills, and foundational concepts from Physics, Chemistry,…

Chemistry and Biology

Science.gov (United States)

Wigston, David L.

1970-01-01

Discusses the relationship between chemisty and biology in the science curriculum. Points out the differences in perception of the disciplines, which the physical scientists favoring reductionism. Suggests that biology departments offer a special course for chemistry students, just as the chemistry departments have done for biology students.…

Climate change and physical disturbance cause similar community shifts in biological soil crusts

Science.gov (United States)

Ferrenberg, Scott; Reed, Sasha C.; Belnap, Jayne

2015-01-01

Biological soil crusts (biocrusts)—communities of mosses, lichens, cyanobacteria, and heterotrophs living at the soil surface—are fundamental components of drylands worldwide, and destruction of biocrusts dramatically alters biogeochemical processes, hydrology, surface energy balance, and vegetation cover. While there has been long-standing concern over impacts of 5 physical disturbances on biocrusts (e.g., trampling by livestock, damage from vehicles), there is also increasing concern over the potential for climate change to alter biocrust community structure. Using long-term data from the Colorado Plateau, USA, we examined the effects of 10 years of experimental warming and altered precipitation (in full-factorial design) on biocrust communities, and compared the effects of altered climate with those of long-term physical 10 disturbance (>10 years of replicated human trampling). Surprisingly, altered climate and physical disturbance treatments had similar effects on biocrust community structure. Warming, altered precipitation frequency [an increase of small (1.2 mm) summer rainfall events], and physical disturbance from trampling all promoted early successional community states marked by dramatic declines in moss cover and increased cyanobacteria cover, with more variable effects 15 on lichens. While the pace of community change varied significantly among treatments, our results suggest that multiple aspects of climate change will affect biocrusts to the same degree as physical disturbance. This is particularly disconcerting in the context of warming, as temperatures for drylands are projected to increase beyond those imposed by the climate treatments used in our study.

Roles of radiation chemistry in development and research of radiation biology

International Nuclear Information System (INIS)

Min Rui

2009-01-01

Radiation chemistry acts as a bridge connecting radiation physics with radiation biology in spatial and temporal insight. The theory, model, and methodology coming from radiation chemistry play an important role in the research and development of radiation biology. The chemical changes induced by ionizing radiation are involved not only in early event of biological effects caused by ionizing radiation but in function radiation biology, such as DNA damage and repair, sensitive modification, metabolism and function of active oxygen and so on. Following the research development of radiation biology, systems radiation biology, accurate quality and quantity of radiation biology effects need more methods and perfect tools from radiation chemistry. (authors)

Advanced Analysis Methods in High Energy Physics

Energy Technology Data Exchange (ETDEWEB)

Pushpalatha C. Bhat

2001-10-03

During the coming decade, high energy physics experiments at the Fermilab Tevatron and around the globe will use very sophisticated equipment to record unprecedented amounts of data in the hope of making major discoveries that may unravel some of Nature's deepest mysteries. The discovery of the Higgs boson and signals of new physics may be around the corner. The use of advanced analysis techniques will be crucial in achieving these goals. The author discusses some of the novel methods of analysis that could prove to be particularly valuable for finding evidence of any new physics, for improving precision measurements and for exploring parameter spaces of theoretical models.

A timeless biology.

Science.gov (United States)

Tozzi, Arturo; Peters, James F; Chafin, Clifford; De Falco, Domenico; Torday, John S

2018-05-01

Contrary to claims that physics is timeless while biology is time-dependent, we take the opposite standpoint: physical systems' dynamics are constrained by the arrow of time, while living assemblies are time-independent. Indeed, the concepts of "constraints" and "displacements" shed new light on the role of continuous time flow in life evolution, allowing us to sketch a physical gauge theory for biological systems in long timescales. In the very short timescales of biological systems' individual lives, time looks like "frozen" and "fixed", so that the second law of thermodynamics is momentarily wrecked. The global symmetries (standing for biological constrained trajectories, i.e. the energetic gradient flows dictated by the second law of thermodynamics in long timescales) are broken by local "displacements" where time is held constant, i.e., modifications occurring in living systems. Such displacements stand for brief local forces, able to temporarily "break" the cosmic increase in entropy. The force able to restore the symmetries (called "gauge field") stands for the very long timescales of biological evolution. Therefore, at the very low speeds of life evolution, time is no longer one of the four phase space coordinates of a spacetime Universe: it becomes just a gauge field superimposed to three-dimensional biological systems. We discuss the implications in biology: when assessing living beings, the underrated role of isolated "spatial" modifications needs to be emphasized, living apart the evolutionary role of time. Copyright © 2017 Elsevier Ltd. All rights reserved.

The physics of photons and neutrons with applications of deuterium labeling methods to polymers

International Nuclear Information System (INIS)

Wignall, G.D.

1986-12-01

Over the past decade small-angle neutron scattering (SANS), has found numerous applications in the fields of biology, polymer science, physical chemistry, materials science, metallurgy, colloids, and solid state physics. A number of excellent references are available which contain basic neutron scattering theory though these text books reflect the origins of the technique and the examples are largely drawn from physics e.g., single crystals, simple liquids, monatomic gases, liquid metals, magnetic materials, etc. in view of the large numbers of nonspecialists who are increasingly using neutron scattering, the need has become apparent for presentations which can provide rapid access to the method without unnecessary detail and mathematical rigor. This article is meant to serve as a general introduction to the symposium ''Scattering Deformation and Fracture in Polymers,'' and is intended to aid potential users who have a general scientific background, but no specialist knowledge of scattering, to apply the technique to provide new information in areas of their own particular interests. In view of space limitations, the general theory will be given in the case for neutron scattering and analogies and differences with photon scattering (x-rays) will be pointed out at the appropriate point. 90 refs., 6 figs

Dynamics and thermodynamics in hierarchically organized systems applications in physics, biology and economics

CERN Document Server

Auger, P

2013-01-01

One of the most fundamental and efficient ways of conceptualizing complex systems is to organize them hierarchically. A hierarchically organized system is represented by a network of interconnected subsystems, each of which has its own network of subsystems, and so on, until some elementary subsystems are reached that are not further decomposed. This original and important book proposes a general mathematical theory of a hierarchical system and shows how it can be applied to very different topics such as physics (Hamiltonian systems), biology (coupling the molecular and the cellular levels), e

openBEB: open biological experiment browser for correlative measurements

OpenAIRE

Ramakrishnan, Chandrasekhar; Bieri, Andrej; Sauter, Nora; Roizard, Sophie; Ringler, Philippe; Müller, Shirley A; Goldie, Kenneth N; Enimanev, Kaloyan; Stahlberg, Henning; Rinn, Bernd; Braun, Thomas

2014-01-01

Background: New experimental methods must be developed to study interaction networks in systems biology. To reduce biological noise, individual subjects, such as single cells, should be analyzed using high throughput approaches. The measurement of several correlative physical properties would further improve data consistency. Accordingly, a considerable quantity of data must be acquired, correlated, catalogued and stored in a database for subsequent analysis. Results: We have developed openBE...

Mathematical methods for physical and analytical chemistry

CERN Document Server

Goodson, David Z

2011-01-01

Mathematical Methods for Physical and Analytical Chemistry presents mathematical and statistical methods to students of chemistry at the intermediate, post-calculus level. The content includes a review of general calculus; a review of numerical techniques often omitted from calculus courses, such as cubic splines and Newton's method; a detailed treatment of statistical methods for experimental data analysis; complex numbers; extrapolation; linear algebra; and differential equations. With numerous example problems and helpful anecdotes, this text gives chemistry students the mathematical

Determination of chorionic gonadotrophin. Comparison of biological, immunological and radioimmunological methods

International Nuclear Information System (INIS)

Munier, M.-P.

1978-07-01

Three types of analysis were used to quantify chorionic gonadotrophic hormone: biological determination (rana-reaction); immunological determination (simplified pregnosticon test of the Organon Teknika laboratories); radioimmunological determination (Commissariat a l'Energie Atomique - CEA kits). While the immunochemical technique is specially suited to analysis of the urine, the radioimmunological measurement is carried out on the plasma. This method is extremely sensitive; when traditional biological and immunological methods are used the quantity of CGH detectable is of the order of some hundreds or at best a few tens of international units. The radioimmunological method is a thousand times more sensitive and can therefore measure CGH in amounts of the milli-unit order. Until recently it was not specific enough to differentiate between CGH and LH, but not long ago a β CGH-specific antibody was discovered and it is now possible to detect small amounts of CGH in the presence of LH [fr

General method to find the attractors of discrete dynamic models of biological systems

Science.gov (United States)

Gan, Xiao; Albert, Réka

2018-04-01

Analyzing the long-term behaviors (attractors) of dynamic models of biological networks can provide valuable insight. We propose a general method that can find the attractors of multilevel discrete dynamical systems by extending a method that finds the attractors of a Boolean network model. The previous method is based on finding stable motifs, subgraphs whose nodes' states can stabilize on their own. We extend the framework from binary states to any finite discrete levels by creating a virtual node for each level of a multilevel node, and describing each virtual node with a quasi-Boolean function. We then create an expanded representation of the multilevel network, find multilevel stable motifs and oscillating motifs, and identify attractors by successive network reduction. In this way, we find both fixed point attractors and complex attractors. We implemented an algorithm, which we test and validate on representative synthetic networks and on published multilevel models of biological networks. Despite its primary motivation to analyze biological networks, our motif-based method is general and can be applied to any finite discrete dynamical system.

General method to find the attractors of discrete dynamic models of biological systems.

Science.gov (United States)

Gan, Xiao; Albert, Réka

2018-04-01

Analyzing the long-term behaviors (attractors) of dynamic models of biological networks can provide valuable insight. We propose a general method that can find the attractors of multilevel discrete dynamical systems by extending a method that finds the attractors of a Boolean network model. The previous method is based on finding stable motifs, subgraphs whose nodes' states can stabilize on their own. We extend the framework from binary states to any finite discrete levels by creating a virtual node for each level of a multilevel node, and describing each virtual node with a quasi-Boolean function. We then create an expanded representation of the multilevel network, find multilevel stable motifs and oscillating motifs, and identify attractors by successive network reduction. In this way, we find both fixed point attractors and complex attractors. We implemented an algorithm, which we test and validate on representative synthetic networks and on published multilevel models of biological networks. Despite its primary motivation to analyze biological networks, our motif-based method is general and can be applied to any finite discrete dynamical system.

Stochastic processes, multiscale modeling, and numerical methods for computational cellular biology

CERN Document Server

2017-01-01

This book focuses on the modeling and mathematical analysis of stochastic dynamical systems along with their simulations. The collected chapters will review fundamental and current topics and approaches to dynamical systems in cellular biology. This text aims to develop improved mathematical and computational methods with which to study biological processes. At the scale of a single cell, stochasticity becomes important due to low copy numbers of biological molecules, such as mRNA and proteins that take part in biochemical reactions driving cellular processes. When trying to describe such biological processes, the traditional deterministic models are often inadequate, precisely because of these low copy numbers. This book presents stochastic models, which are necessary to account for small particle numbers and extrinsic noise sources. The complexity of these models depend upon whether the biochemical reactions are diffusion-limited or reaction-limited. In the former case, one needs to adopt the framework of s...

Physical Model Method for Seismic Study of Concrete Dams

Directory of Open Access Journals (Sweden)

Bogdan Roşca

2008-01-01

Full Text Available The study of the dynamic behaviour of concrete dams by means of the physical model method is very useful to understand the failure mechanism of these structures to action of the strong earthquakes. Physical model method consists in two main processes. Firstly, a study model must be designed by a physical modeling process using the dynamic modeling theory. The result is a equations system of dimensioning the physical model. After the construction and instrumentation of the scale physical model a structural analysis based on experimental means is performed. The experimental results are gathered and are available to be analysed. Depending on the aim of the research may be designed an elastic or a failure physical model. The requirements for the elastic model construction are easier to accomplish in contrast with those required for a failure model, but the obtained results provide narrow information. In order to study the behaviour of concrete dams to strong seismic action is required the employment of failure physical models able to simulate accurately the possible opening of joint, sliding between concrete blocks and the cracking of concrete. The design relations for both elastic and failure physical models are based on dimensional analysis and consist of similitude relations among the physical quantities involved in the phenomenon. The using of physical models of great or medium dimensions as well as its instrumentation creates great advantages, but this operation involves a large amount of financial, logistic and time resources.

Effective Teaching Methods--Project-based Learning in Physics

Science.gov (United States)

Holubova, Renata

2008-01-01

The paper presents results of the research of new effective teaching methods in physics and science. It is found out that it is necessary to educate pre-service teachers in approaches stressing the importance of the own activity of students, in competences how to create an interdisciplinary project. Project-based physics teaching and learning…

A graphical method for reducing and relating models in systems biology.

Science.gov (United States)

Gay, Steven; Soliman, Sylvain; Fages, François

2010-09-15

In Systems Biology, an increasing collection of models of various biological processes is currently developed and made available in publicly accessible repositories, such as biomodels.net for instance, through common exchange formats such as SBML. To date, however, there is no general method to relate different models to each other by abstraction or reduction relationships, and this task is left to the modeler for re-using and coupling models. In mathematical biology, model reduction techniques have been studied for a long time, mainly in the case where a model exhibits different time scales, or different spatial phases, which can be analyzed separately. These techniques are however far too restrictive to be applied on a large scale in systems biology, and do not take into account abstractions other than time or phase decompositions. Our purpose here is to propose a general computational method for relating models together, by considering primarily the structure of the interactions and abstracting from their dynamics in a first step. We present a graph-theoretic formalism with node merge and delete operations, in which model reductions can be studied as graph matching problems. From this setting, we derive an algorithm for deciding whether there exists a reduction from one model to another, and evaluate it on the computation of the reduction relations between all SBML models of the biomodels.net repository. In particular, in the case of the numerous models of MAPK signalling, and of the circadian clock, biologically meaningful mappings between models of each class are automatically inferred from the structure of the interactions. We conclude on the generality of our graphical method, on its limits with respect to the representation of the structure of the interactions in SBML, and on some perspectives for dealing with the dynamics. The algorithms described in this article are implemented in the open-source software modeling platform BIOCHAM available at http

An entrepreneurial physics method and its experimental test

Science.gov (United States)

Brown, Robert

2012-02-01

As faculty in a master's program for entrepreneurial physics and in an applied physics PhD program, I have advised upwards of 40 master and doctoral theses in industrial physics. I have been closely involved with four robust start-up manufacturing companies focused on physics high-technology and I have spent 30 years collaborating with industrial physicists on research and development. Thus I am in a position to reflect on many articles and advice columns centered on entrepreneurship. What about the goals, strategies, resources, skills, and the 10,000 hours needed to be an entrepreneur? What about business plans, partners, financing, patents, networking, salesmanship and regulatory affairs? What about learning new technology, how to solve problems and, in fact, learning innovation itself? At this point, I have my own method to propose to physicists in academia for incorporating entrepreneurship into their research lives. With this method, we do not start with a major invention or discovery, or even with a search for one. The method is based on the training we have, and the teaching we do (even quantum electrodynamics!), as physicists. It is based on the networking we build by 1) providing courses of continuing education for people working in industry and 2) through our undergraduate as well as graduate students who have gone on to work in industry. In fact, if we were to be limited to two words to describe the method, they are ``former students.'' Data from local and international medical imaging manufacturing industry are presented.

Interpretation of biological and mechanical variations between the Lowry versus Bradford method for protein quantification.

Science.gov (United States)

Lu, Tzong-Shi; Yiao, Szu-Yu; Lim, Kenneth; Jensen, Roderick V; Hsiao, Li-Li

2010-07-01

The identification of differences in protein expression resulting from methodical variations is an essential component to the interpretation of true, biologically significant results. We used the Lowry and Bradford methods- two most commonly used methods for protein quantification, to assess whether differential protein expressions are a result of true biological or methodical variations. MATERIAL #ENTITYSTARTX00026; Differential protein expression patterns was assessed by western blot following protein quantification by the Lowry and Bradford methods. We have observed significant variations in protein concentrations following assessment with the Lowry versus Bradford methods, using identical samples. Greater variations in protein concentration readings were observed over time and in samples with higher concentrations, with the Bradford method. Identical samples quantified using both methods yielded significantly different expression patterns on Western blot. We show for the first time that methodical variations observed in these protein assay techniques, can potentially translate into differential protein expression patterns, that can be falsely taken to be biologically significant. Our study therefore highlights the pivotal need to carefully consider methodical approaches to protein quantification in techniques that report quantitative differences.

Biological intrusion of low-level-waste trench covers

International Nuclear Information System (INIS)

Hakonson, T.E.; Gladney, E.S.

1981-01-01

The long-term integrity of low-level waste shallow land burial sites is dependent on the interaction of physical, chemical, and biological factors that modify the waste containment system. Past research on low-level waste shallow land burial methods has emphasized physical (i.e., water infiltration, soil erosion) and chemical (radionuclide leaching) processes that can cause waste site failure and subsequent radionuclide transport. The purpose of this paper is to demonstrate the need to consider biological processes as being potentially important in reducing the integrity of waste burial site cover treatments. Plants and animals not only can transport radionuclides to the ground surface via root systems and soil excavated from the cover profile by animal burrowing activities, but they modify physical and chemical processes within the cover profile by changing the water infiltration rates, soil erosion rates and chemical composition of the soil. One approach to limiting biological intrusion through the waste cover is to apply a barrier within the profile to limit root and animal penetration with depth. Experiments in the Los Alamos Experimental Engineered Test Facility were initiated to develop and evaluate biological barriers that are effective in minimizing intrusion into waste trenches. The experiments that are described employ four different candidate barrier materials of geologic origin. Experimental variables that will be evaluated, in addition to barrier type, are barrier depth and soil overburden depth. The rate of biological intrusion through the various barrier materials is being evaluated through the use of activatable stable tracers

Methods of teaching the physics of climate change in undergraduate physics courses

Science.gov (United States)

Sadler, Michael

2015-04-01

Although anthropogenic climate change is generally accepted in the scientific community, there is considerable skepticism among the general population and, therefore, in undergraduate students of all majors. Students are often asked by their peers, family members, and others, whether they ``believe'' climate change is occurring and what should be done about it (if anything). I will present my experiences and recommendations for teaching the physics of climate change to both physics and non-science majors. For non-science majors, the basic approach is to try to develop an appreciation for the scientific method (particularly peer-reviewed research) in a course on energy and the environment. For physics majors, the pertinent material is normally covered in their undergraduate courses in modern physics and thermodynamics. Nevertheless, it helps to review the basics, e.g. introductory quantum mechanics (discrete energy levels of atomic systems), molecular spectroscopy, and blackbody radiation. I have done this in a separate elective topics course, titled ``Physics of Climate Change,'' to help the students see how their knowledge gives them insight into a topic that is very volatile (socially and politically).

Cumulative and Synergistic Effects of Physical, Biological, and Acoustic Signals on Marine Mammal Habitat Use Physical Oceanography Component: Soundscapes Under Sea Ice: Can We Listen for Open Water?

Science.gov (United States)

2013-09-30

Physical, Biological, and Acoustic Signals on Marine Mammal Habitat Use Physical Oceanography Component: Soundscapes Under Sea Ice: Can we listen for... Soundscapes Under Sea Ice: Can we listen for open water? 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...the source. These different sounds can be described as “ soundscapes ”, and graphically represented by comparing two or more features of the sound

Dose estimation of heavy ion beam by microdosimetry. Examination of the method to estimate biological effect from physical measurement of radiation quality

International Nuclear Information System (INIS)

Kase, Yuki; Sakama, Makoto; Tsuzuki, Daigo; Abe, Kyoko; Saotome, Naoya; Matsufuji, Naruhiro; Kanai, Tatsuaki; Matsumoto, Kouki; Furusawa, Yoshiya

2007-01-01

The absorbed dose (AD) of heavy ion (HI) beam (here, carbon beam) in HI therapy (unit, EGy) (D st ) to exert the actual clinical effect is for the irradiation of tumors deep in the body and is thus estimated by AD corrected with the relative biological effectiveness (RBE) of clinical endpoint: i.e., the relation is expressed by the equation RBE=D st /D rad | same-effect (D rad is AD of the reference X-ray to yield the same effect as the HI used for the intended clinical endpoint). This paper describes the process of the estimation in the title with consideration of depth dependences of AD of HI in accordance to Bragg curve, and of biological AD as determined by colony assay of human salivary gland tumor cells: in NIRS, the desired AD in HI therapy is calculated by multiplying 1.5 to physically measured AD of HI at RBE 10% (10% survival of the cells). This factor has been obtained by microdosimetry of Heavy Ion Medical Accelerator in Chiba (HIMAC) ions in NIRS with a small spherical proportional counter (LET-1/2, Far West Technology) of the diameter 1.27 cm having the tissue equivalent plastic wall and chamber filled with 4.4 kPa of propane-based gas to make the tissue-equivalence size 1.0 μm diameter. The measuring principle is based on the microdosimetric kinetic model reported previously. The calculated dose is found to agree with AD in HI therapeutic planning within 10% fluctuation. (R.T.)

Importancia de la biología molecular para la Fisioterapia moderna Importance of molecular biology for the modern Physical Therapy

Directory of Open Access Journals (Sweden)

Carolina Ramírez Ramírez

2011-12-01

Full Text Available Para que el cuerpo de conocimiento de una profesión crezca y se fortalezca debe estar al día con los avances científicos y tecnológicos que surgen continuamente para incluirlos en el repertorio de recursos que usa para la investigación de problemas específicos de su saber. Recientemente el desciframiento del código genético y la secuenciación del genoma humano creó la base para el surgimiento de metodologías y técnicas en el área de la biología molecular, las cuales permitieron profundizar en el conocimiento de la estructura y función de los tejidos humanos y también mejoraron el entendimiento de los mecanismos por los cuales actúan formas de intervención usadas cotidianamente por profesionales en salud. La Fisioterapia utiliza modalidades físicas que interactúan con los tejidos corporales, por ello la biología molecular permite un mejor entendimiento de los efectos que las dichas modalidades generan en el tejido sobre el cual son aplicadas. Por tanto el objetivo de este artículo es reflexionar sobre la necesidad de que el Fisioterapeuta se apropie del conocimiento en ésta área de las ciencias básicas, usarlo como herramienta para la solución de preguntas relevantes de su quehacer clínico y así contribuir de manera efectiva con la generación de nuevo conocimiento que promueva la práctica basada en la evidencia y fomente el crecimiento de la profesión. Salud UIS 2011; 43 (3: 317-320A profession can be improved through the development and application of scientific and technological advances around the issues relating to their expertise. Recently, the deciphering of the genetic code and human genome sequencing creates the basis for the development of methodologies and techniques of molecular biology. These resources have allowed a deeper understanding of the human tissue structure and function, and intervention mechanisms used by health professionals. Physiotherapy uses physical modalities affecting the tissues of the

Numerical methods in physical and economic sciences

International Nuclear Information System (INIS)

Lions, J.L.; Marchouk, G.I.

1974-01-01

This book is the first of a series to be published simultaneously in French and Russian. Some results obtained in the framework of an agreement of French-Soviet scientific collaboration in the field of the information processing are exposed. In the first part, the iterative methods for solving linear systems are studied with new methods which are compared to already known methods. Iterative methods of minimization of quadratic functionals are then studied. In the second part, the optimization problems with one or many criteria, issued from Physics and Economics problems are considered and splitting and decentralizing methods systematically studied [fr

Review of multi-physics temporal coupling methods for analysis of nuclear reactors

International Nuclear Information System (INIS)

Zerkak, Omar; Kozlowski, Tomasz; Gajev, Ivan

2015-01-01

Highlights: • Review of the numerical methods used for the multi-physics temporal coupling. • Review of high-order improvements to the Operator Splitting coupling method. • Analysis of truncation error due to the temporal coupling. • Recommendations on best-practice approaches for multi-physics temporal coupling. - Abstract: The advanced numerical simulation of a realistic physical system typically involves multi-physics problem. For example, analysis of a LWR core involves the intricate simulation of neutron production and transport, heat transfer throughout the structures of the system and the flowing, possibly two-phase, coolant. Such analysis involves the dynamic coupling of multiple simulation codes, each one devoted to the solving of one of the coupled physics. Multiple temporal coupling methods exist, yet the accuracy of such coupling is generally driven by the least accurate numerical scheme. The goal of this paper is to review in detail the approaches and numerical methods that can be used for the multi-physics temporal coupling, including a comprehensive discussion of the issues associated with the temporal coupling, and define approaches that can be used to perform multi-physics analysis. The paper is not limited to any particular multi-physics process or situation, but is intended to provide a generic description of multi-physics temporal coupling schemes for any development stage of the individual (single-physics) tools and methods. This includes a wide spectrum of situation, where the individual (single-physics) solvers are based on pre-existing computation codes embedded as individual components, or a new development where the temporal coupling can be developed and implemented as a part of code development. The discussed coupling methods are demonstrated in the framework of LWR core analysis

Preparation of Biological Samples Containing Metoprolol and Bisoprolol for Applying Methods for Quantitative Analysis

Directory of Open Access Journals (Sweden)

Corina Mahu Ştefania

2015-12-01

Full Text Available Arterial hypertension is a complex disease with many serious complications, representing a leading cause of mortality. Selective beta-blockers such as metoprolol and bisoprolol are frequently used in the management of hypertension. Numerous analytical methods have been developed for the determination of these substances in biological fluids, such as liquid chromatography coupled with mass spectrometry, gas chromatography coupled with mass spectrometry, high performance liquid chromatography. Due to the complex composition of biological fluids a biological sample pre-treatment before the use of the method for quantitative determination is required in order to remove proteins and potential interferences. The most commonly used methods for processing biological samples containing metoprolol and bisoprolol were identified through a thorough literature search using PubMed, ScienceDirect, and Willey Journals databases. Articles published between years 2005-2015 were reviewed. Protein precipitation, liquid-liquid extraction and solid phase extraction are the main techniques for the extraction of these drugs from plasma, serum, whole blood and urine samples. In addition, numerous other techniques have been developed for the preparation of biological samples, such as dispersive liquid-liquid microextraction, carrier-mediated liquid phase microextraction, hollow fiber-protected liquid phase microextraction, on-line molecularly imprinted solid phase extraction. The analysis of metoprolol and bisoprolol in human plasma, urine and other biological fluids provides important information in clinical and toxicological trials, thus requiring the application of appropriate extraction techniques for the detection of these antihypertensive substances at nanogram and picogram levels.

Physical and Biological Regulation of Carbon Sequestration in Tidal Marshes

Science.gov (United States)

Morris, J. T.; Callaway, J.

2017-12-01

The rate of carbon sequestration in tidal marshes is regulated by complex feedbacks among biological and physical factors including the rate of sea-level rise (SLR), biomass production, tidal amplitude, and the concentration of suspended sediment. We used the Marsh Equilibrium Model (MEM) to explore the effects on C-sequestration across a wide range of permutations of these variables. C-sequestration increased with the rate of SLR to a maximum, then down to a vanishing point at higher SLR when marshes convert to mudflats. An acceleration in SLR will increase C-sequestration in marshes that can keep pace, but at high rates of SLR this is only possible with high biomass and suspended sediment concentrations. We found that there were no feasible solutions at SLR >13 mm/yr for permutations of variables that characterize the great majority of tidal marshes, i.e., the equilibrium elevation exists below the lower vertical limit for survival of marsh vegetation. The rate of SLR resulting in maximum C-sequestration varies with biomass production. C-sequestration rates at SLR=1 mm/yr averaged only 36 g C m-2 yr-1, but at the highest maximum biomass tested (5000 g/m2) the mean C-sequestration reached 399 g C m-2 yr-1 at SLR = 14 mm/yr. The empirical estimate of C-sequestration in a core dated 50-years overestimates the theoretical long-term rate by 34% for realistic values of decomposition rate and belowground production. The overestimate of the empirical method arises from the live and decaying biomass contained within the carbon inventory above the marker horizon, and overestimates were even greater for shorter surface cores.

Are biological effects of desert shrubs more important than physical effects on soil microorganisms?

Science.gov (United States)

Berg, Naama; Steinberger, Yosef

2010-01-01

Vegetation cover plays a major role in providing organic matter and in acting as a physical barrier, with both together contributing to the formation of "fertile islands," which play an active role in prolonging biological activity in desert ecosystems. By undertaking this study, a longterm research, we designed an experiment to separate the two components-the physical and biotic parts of the perennial plants-and to identify the factor that contributes the most to the ecosystem. The study site was located in the northern Negev Desert, Israel, where 50 Hammada scoparia shrubs and 50 artificial plants were randomly marked. Soil samples were collected monthly over 3 years of research at three locations: under the canopy of H. scoparia shrubs, in the vicinity of the artificial plants, and between the shrubs (control). The contribution to microbial activity was measured by evaluation of the microbial community functions in soil. The functional aspects of the microbial community that were measured were CO2 evolution, microbial biomass, microbial functional diversity, and the physiological profile of the community. The results of this study are presented in two ways: (1) according to the three locations/treatments; and (2) according to the phenological situation of the vegetation (annual and perennial plants) in the research field: the growing phase, the drying process, and the absence of annual plants. The only parameters that were found to affect microbial activity were the contribution of the organic matter of perennial shrubs and the growth of vegetation (annual and perennial) during the growing seasons. The physical component was found to have no effect on soil microbial functional diversity, which elucidates the important contribution of the desert shrub in enhancing biological multiplicity and activity.

Clinical oncology based upon radiation biology

International Nuclear Information System (INIS)

Hirata, Hideki

2016-01-01

This paper discussed the biological effects of radiation as physical energy, especially those of X-ray as electromagnetic radiation, by associating the position of clinical oncology with classical radiation cell biology as well as recent molecular biology. First, it described the physical and biological effects of radiation, cell death due to radiation and recovery, radiation effects at tissue level, and location information and dosage information in the radiotherapy of cancer. It also described the territories unresolved through radiation biology, such as low-dose high-sensitivity, bystander effects, etc. (A.O.)

DEGRO 2009. Radiation oncology - medical physics - radiation biology. Abstracts; DEGRO 2009. Radioonkologie - Medizinische Physik - Strahlenbiologie. Abstracts

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-06-15

The special volume of the journal covers the abstracts of the DEGRO 2009 meeting on radiation oncology, medical physics, and radiation biology, covering the following topics: seldom diseases, gastrointestinal tumors, radiation reactions and radiation protection, medical care and science, central nervous system, medical physics, the non-parvicellular lung carcinomas, ear-nose-and throat, target-oriented radiotherapy plus ''X'', radio-oncology - young academics, lymphomas, mammary glands, modern radiotherapy, life quality and palliative radiotherapy, radiotherapy of the prostate carcinoma, imaging for planning and therapy, the digital documentation in clinics and practical experiences, NMR imaging and tomography, hadrons - actual status in Germany, urinal tract oncology, radiotoxicity.

A Method for Determining the Content of Glycoproteins in Biological Samples

Directory of Open Access Journals (Sweden)

Yang Gao

2016-11-01

Full Text Available The glycoprotein purified from the mycelium extract of Tremella fuciformis was marked with iodine through the iodine substitution reaction. The content of iodine, which is indicative of the amount of the marked tremella glycoprotein (ITG, was detected with Inductively coupled plasma mass spectrometry (ICP-MS. The method was found to be stable, sensitive, and accurate at detecting the content of iodine-substituted glycoprotein, and was used in the quantitative analysis of biological samples, including blood and organs. Different biological samples were collected from rats after oral administration of ITG, and were tested for iodine content by ICP-MS to calculate the amount of ITG in the samples. The results suggested that ICP-MS is a sensitive, stable, and accurate method for detection of iodinated glycoproteins in blood and organs.

Physics-based signal processing algorithms for micromachined cantilever arrays

Science.gov (United States)

Candy, James V; Clague, David S; Lee, Christopher L; Rudd, Robert E; Burnham, Alan K; Tringe, Joseph W

2013-11-19

A method of using physics-based signal processing algorithms for micromachined cantilever arrays. The methods utilize deflection of a micromachined cantilever that represents the chemical, biological, or physical element being detected. One embodiment of the method comprises the steps of modeling the deflection of the micromachined cantilever producing a deflection model, sensing the deflection of the micromachined cantilever and producing a signal representing the deflection, and comparing the signal representing the deflection with the deflection model.