Energy levels of QED in a Euclidean formulation
Hydrogen-like energy levels of scalar and spinor QED are calculated using a Euclidean functional approach. The matter field is integrated over. Stationary points of the resulting effective action already yield a hydrogen like level structure for the energy. There is an interesting difference between the scalar and the spinor case. Whereas for spinors the conventional results are reproduced, the calculation for scalars yields a fine structure which is opposite in sign to the conventional one and has no critical singularity at Zα = 1/2. The crucial structural difference between the two cases is that, for scalars, minima for the gauge invariant energy are not extrema of the action, even for time independent fields. (orig.)
Theodoridou, Panagiota G.; Karatzas, George P.; Varouchakis, Emmanouil A.; Corzo Perez, Gerald A.
2015-04-01
Groundwater level is an important information in hydrological modelling. Geostatistical methods are often employed to map the free surface of an aquifer. In geostatistical analysis using Kriging techniques the selection of the optimal variogram model is very important for the optimal method performance. This work compares three different criteria, the least squares sum method, the Akaike Information Criterion and the Cressie's Indicator, to assess the theoretical variogram that fits to the experimental one and investigates the impact on the prediction results. Moreover, five different distance functions (Euclidean, Minkowski, Manhattan, Canberra, and Bray-Curtis) are applied to calculate the distance between observations that affects both the variogram calculation and the Kriging estimator. Cross validation analysis in terms of Ordinary Kriging is applied by using sequentially a different distance metric and the above three variogram fitting criteria. The spatial dependence of the observations in the tested dataset is studied by fitting classical variogram models and the Matérn model. The proposed comparison analysis performed for a data set of two hundred fifty hydraulic head measurements distributed over an alluvial aquifer that covers an area of 210 km2. The study area is located in the Prefecture of Drama, which belongs to the Water District of East Macedonia (Greece). This area was selected in terms of hydro-geological data availability and geological homogeneity. The analysis showed that a combination of the Akaike information Criterion for the variogram fitting assessment and the Brays-Curtis distance metric provided the most accurate cross-validation results. The Power-law variogram model provided the best fit to the experimental data. The aforementioned approach for the specific dataset in terms of the Ordinary Kriging method improves the prediction efficiency in comparison to the classical Euclidean distance metric. Therefore, maps of the spatial
Quantum information processing at the cellular level. Euclidean approach
Ogryzko, Vasily
2009-01-01
Application of quantum principles to living cells requires a new approximation of the full quantum mechanical description of intracellular dynamics. We discuss what principal elements any such good approximation should contain. As one such element, the notion of "Catalytic force" Cf is introduced. Cf is the effect of the molecular target of catalysis on the catalytic microenvironment that adjusts the microenvironment towards a state that facilitates the catalytic act. This phenomenon is exper...
Saifudin Saifudin
2015-10-01
Full Text Available Kayu jati (Tectona Grandis L.F. dan mahoni (Swietenia Mahagoni merupakan 2 jenis kayu yang biasa digunakan untuk bahan perabot rumah tangga. Perabot yang berbahan kayu jati dikenal sebagai produk kwalitas kelas 1 sedangkan perabot dengan bahan kayu mahoni dianggap sebagai produk kwalitas kelas ke 2. Namun secara manual sulit untuk membedakan antara kedua jenis kayu ini. Oleh karenanya penting dibangunnya suatu sistem otomatis yang mampu mengenali perbedaan dari kedua jenis kayu ini. Pada dasarnya citra kayu dapat dianalisis cirinya untuk mendapatkan pola-pola yang menunjukkan jenis kayu. Ekstraksi ciri dari citra kayu dapat dianalisi berdasarkan tekstur atau warnanya.Tulisan ini menjelaskan sistem identifikasi jenis kayu yang telah dikembangkan untuk membedakan antara jenis kayu jati atau mahoni. Sistem ini meliputi proses akusisi data citra, pemrosesan citra, ekstraksi ciri, dan klasifikasi. Ekstraksi ciri menggunakan tekstur Gray Level Co-ocurrence Matrix (GLCM sedangkan pengklasikasi menggunakan metode jarak Euclidean. Hasil eksperimen-eksperimen dengan pengubahan ukuran citra asli menjadi 30x30, 20x20 dan 10x10 berturut-turut menghasilkan akurasi 82,5 %, 65,7 % dan 77,5%. Hasil ini menunjukkan bahwa akurasi tertinggi yang diperoleh layak untuk diimplementasikan ke dalam industri
Repaglinide at a cellular level
Krogsgaard Thomsen, M; Bokvist, K; Høy, M;
2002-01-01
To investigate the hormonal and cellular selectivity of the prandial glucose regulators, we have undertaken a series of experiments, in which we characterised the effects of repaglinide and nateglinide on ATP-sensitive potassium ion (KATP) channel activity, membrane potential and exocytosis in ra...
Cellular-based sea level gauge
Desai, R.G.P.; Joseph, A.
treaties with greater transparency. Among the various communication technologies used for real-time transmission of sea-level data are the wired telephone connection, VHF/UHF transceivers, satellite transmit terminals and cellular connectivity. Wired... telephone connections are severely susceptible to loss of connectivity during natural disasters such as storm surges, primarily because of telephone line breakage. Communication via VHF/UHF transceivers is limited by line-of-sight distance between...
Guerra, Francesco
2005-01-01
A coincise review about Euclidean (Quantum) Field Theory is presented. It deals with the general structural properties, the connections with Quantum Field Theory, the exploitation in Constructive Quantum Field Theory, and the physical interpretation.
Trudeau, Richard J
1986-01-01
How unique and definitive is Euclidean geometry in describing the "real" space in which we live? Richard Trudeau confronts the fundamental question of truth and its representation through mathematical models in The Non-Euclidean Revolution. First, the author analyzes geometry in its historical and philosophical setting; second, he examines a revolution every bit as significant as the Copernican revolution in astronomy and the Darwinian revolution in biology; third, on the most speculative level, he questions the possibility of absolute knowledge of the world. Trudeau writes in a lively, entertaining, and highly accessible style. His book provides one of the most stimulating and personal presentations of a struggle with the nature of truth in mathematics and the physical world. A portion of the book won the Pólya Prize, a distinguished award from the Mathematical Association of America. "Trudeau meets the challenge of reaching a broad audience in clever ways...(The book) is a good addition to our literature o...
Bonola, Roberto
2010-01-01
This is an excellent historical and mathematical view by a renowned Italian geometer of the geometries that have risen from a rejection of Euclid's parallel postulate. Students, teachers and mathematicians will find here a ready reference source and guide to a field that has now become overwhelmingly important.Non-Euclidean Geometry first examines the various attempts to prove Euclid's parallel postulate-by the Greeks, Arabs, and mathematicians of the Renaissance. Then, ranging through the 17th, 18th and 19th centuries, it considers the forerunners and founders of non-Euclidean geometry, such
Observables of Euclidean Supergravity
Vancea, Ion V.
1997-10-01
The set of constraints under which the eigenvalues of the Dirac operator can play the role of the dynamical variables for Euclidean supergravity is derived. These constraints arise when the gauge invariance of the eigenvalues of the Dirac operator is imposed. They impose conditions which restrict the eigenspinors of the Dirac operator.
Introductory non-Euclidean geometry
Manning, Henry Parker
2013-01-01
This fine and versatile introduction begins with the theorems common to Euclidean and non-Euclidean geometry, and then it addresses the specific differences that constitute elliptic and hyperbolic geometry. 1901 edition.
Euclidean distance geometry and applications
Liberti, Leo; Lavor, Carlile; Maculan, Nelson; Mucherino, Antonio
2012-01-01
Euclidean distance geometry is the study of Euclidean geometry based on the concept of distance. This is useful in several applications where the input data consists of an incomplete set of distances, and the output is a set of points in Euclidean space that realizes the given distances. We survey some of the theory of Euclidean distance geometry and some of the most important applications: molecular conformation, localization of sensor networks and statics.
Graviperception and graviresponse at the cellular level
Bräucker, Richard; Cogoli, Augusto; Hemmersbach, Ruth
Studies under varied acceleration conditions demonstrated that free living cells such as protists are able to perceive changes of the acceleration conditions. Recent studies favorite the hypothesis that in these systems gravity is perceived either by intracellular receptors (statocyst-like organelles), heavy cell organelles (such as nucleus) and/or by sensing the cell mass by means of ion channels located in the cell membrane. Mammalian cells in microgravity were profoundly influenced. Alteration in the cellular mechanisms and structures in mammalian cells like signal transduction and the cytoskeleton were detected. It can be speculated that the depression of the immune system may become a serious health issue on flights to and from Mars.
Greenacre, Michael J.; Groenen, Patrick J. F.
2013-01-01
We construct a weighted Euclidean distance that approximates any distance or dissimilarity measure between individuals that is based on a rectangular cases-by-variables data matrix. In contrast to regular multidimensional scaling methods for dissimilarity data, the method leads to biplots of individuals and variables while preserving all the good properties of dimension-reduction methods that are based on the singular-value decomposition. The main benefits are the decomposition of variance in...
Hoffman, Kenneth
2007-01-01
Developed for an introductory course in mathematical analysis at MIT, this text focuses on concepts, principles, and methods. Its introductions to real and complex analysis are closely formulated, and they constitute a natural introduction to complex function theory.Starting with an overview of the real number system, the text presents results for subsets and functions related to Euclidean space of n dimensions. It offers a rigorous review of the fundamentals of calculus, emphasizing power series expansions and introducing the theory of complex-analytic functions. Subsequent chapters cover seq
Modeling cellular deformations using the level set formalism
Yang Liu; Effler Janet C; Kutscher Brett L; Sullivan Sarah E; Robinson Douglas N; Iglesias Pablo A
2008-01-01
Abstract Background Many cellular processes involve substantial shape changes. Traditional simulations of these cell shape changes require that grids and boundaries be moved as the cell's shape evolves. Here we demonstrate that accurate cell shape changes can be recreated using level set methods (LSM), in which the cellular shape is defined implicitly, thereby eschewing the need for updating boundaries. Results We obtain a viscoelastic model of Dictyostelium cells using micropipette aspiratio...
Modeling cellular deformations using the level set formalism
Yang Liu
2008-07-01
Full Text Available Abstract Background Many cellular processes involve substantial shape changes. Traditional simulations of these cell shape changes require that grids and boundaries be moved as the cell's shape evolves. Here we demonstrate that accurate cell shape changes can be recreated using level set methods (LSM, in which the cellular shape is defined implicitly, thereby eschewing the need for updating boundaries. Results We obtain a viscoelastic model of Dictyostelium cells using micropipette aspiration and show how this viscoelastic model can be incorporated into LSM simulations to recreate the observed protrusion of cells into the micropipette faithfully. We also demonstrate the use of our techniques by simulating the cell shape changes elicited by the chemotactic response to an external chemoattractant gradient. Conclusion Our results provide a simple but effective means of incorporating cellular deformations into mathematical simulations of cell signaling. Such methods will be useful for simulating important cellular events such as chemotaxis and cytokinesis.
Totally indefinite Euclidean quaternion fields
Cerri, Jean-Paul; Chaubert, Jérôme; Lezowski, Pierre
2014-01-01
We study the Euclidean property for totally indefinite quaternion fields. In particular, we establish the complete list of norm-Euclidean such fields over imaginary quadratic number fields. This enables us to exhibit an example which gives a negative answer to a question asked by Eichler. The proofs are both theoretical and algorithmic.
On Nearly Euclidean Thurston Maps
Saenz Maldonado, Edgar Arturo
2012-01-01
Nearly Euclidean Thurston maps are simple generalizations of rational Lattes maps. A Thurston map is called nearly Euclidean if its local degree at each critical point is 2 and it has exactly four postcritical points. We investigate when such a map has the property that the associated pullback map on Teichmuller space is constant. We also show that no Thurston map of degree 2 has constant pullback map.
Body composition analysis: Cellular level modeling of body component ratios
Z. Wang; Heymsfield, S. B.; PI-SUNYER, F.X.; Gallagher, D.; PIERSON, R.N.
2008-01-01
During the past two decades, a major outgrowth of efforts by our research group at St. Luke’s-Roosevelt Hospital is the development of body composition models that include cellular level models, models based on body component ratios, total body potassium models, multi-component models, and resting energy expenditure-body composition models. This review summarizes these models with emphasis on component ratios that we believe are fundamental to understanding human body composition during growt...
Concepts of dose to soft tissue at the cellular level
Radiation effects begin at the cellular level of biological organization. Radiation dosimetry at the cellular level is particularly important for internally deposited alpha and beta particle emitters. Microdosimetry is a mechanism for studying the dose imparted to microscopic sites, for determining hit probabilities, and for determining the probability that sites are missed. Internal microdosimetry calculations are complex, but can be easily executed using computer programs. The investigator must specify the target and its size, determine the radionuclide activity per unit mass for each region in which targets are located, describe the activity per radioactive particulate, understand the geometrical relationship between the activity and the targets, and account for the biological retention of the activity in the region as a function of time. Internal microdosimetry has many potential applications in radiological protection. Microdosimetry is a special research area designed to provide a better understanding of the importance of microscopic patterns of radiation interaction with cells within the broader framework of biochemistry and radiation biology. Its objective is to provide a methodology that is both consistent and precise for correlating biological response to varying levels and distributions of internal emitters. Microdosimetry may contribute to a more complete understanding of the mechanisms of cancer induction by radiation. The correlation between specific energy density and various biological effects might best be treated statistically, since the effects occur in response of stochastic processes. If applied correctly, these concepts should provide a reliable tool for learning more about the effects of radiation and for setting radiation protection standards
Observables of the Euclidean Supergravity
Vancea, Ion V.
1997-01-01
The set of constraints under which the eigenvalues of the Dirac operator can play the role of the dynamical variables for Euclidean supergravity is derived. These constraints arise when the gauge invariance of the eigenvalues of the Dirac operator is imposed. They impose conditions which restrict the eigenspinors of the Dirac operator.
Electrochemical Biochip for Drug Screening At Cellular Level
Chen Yu [Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore); Cui Huiang [Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543 (Singapore); Ye Jianshan [Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543 (Singapore); Chong Serchoong [Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore); Lim Titmeng [Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543 (Singapore); Sheu Fwushan [Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543 (Singapore); Hui Wingcheong [Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore)
2006-04-01
Drug screening at cellular level has becomes an attractive field of research. Different researchers have tried to record cellular response to drugs by electrical or optical approach using both invasive and non-invasive methods. Silicon-based microelectrode integrated microchips are useful tools for in situ temporal recording of neurotransmitter releasing from neural cells. A microfabricated electrochemical biochip is presented in this paper. Using dopaminergic cells grown on the chip, the dopamine excytosis can be electrochemical amperomatric detected non-invasively from drug incubated dopaminegic cells by the microelectrode integrated on chip. This silicon-based electrochemical chip has been designed with an electrode array located on the cell culture chamber bottom. Each electrode is individually electrical controlled. MN9D and PC12 dopaminergic cell lines have been demonstrated on this chip for drug effects study. This silicon-based electrochemical microchip provides a non-invasive, in situ, temporal detection of dopamine exocytosis from dopaminegic cells, and holds the potential for applications in studying the mechanisms of dopamine exocytosis and drug screening. It is also extendable for other cell culture and drug effects study.
Cellular chromophores and signaling in low level light therapy
Hamblin, Michael R.; Demidova-Rice, Tatiana N.
2007-02-01
The use of low levels of visible or near infrared light (LLLT) for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing tissue damage by reducing cellular apoptosis has been known for almost forty years since the invention of lasers. Originally thought to be a peculiar property of laser light (soft or cold lasers), the subject has now broadened to include photobiomodulation and photobiostimulation using non-coherent light. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial. This likely is due to two main reasons; firstly the biochemical mechanisms underlying the positive effects are incompletely understood, and secondly the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. In recent years major advances have been made in understanding the mechanisms that operate at the cellular and tissue levels during LLLT. Mitochondria are thought to be the main site for the initial effects of light and specifically cytochrome c oxidase that has absorption peaks in the red and near infrared regions of the electromagnetic spectrum matches the action spectra of LLLT effects. The discovery that cells employ nitric oxide (NO) synthesized in the mitochondria by neuronal nitric oxide synthase, to regulate respiration by competitive binding to the oxygen binding of cytochrome c oxidase, now suggests how LLLT can affect cell metabolism. If LLLT photodissociates inhibitory NO from cytochrome c oxidase, this would explain increased ATP production, modulation of reactive oxygen species, reduction and prevention of apoptosis, stimulation of angiogenesis, increase of blood flow and induction of transcription factors. In
An axiomatization of the Euclidean compromise solution
Voorneveld, M.; Nouweland, A. van den
2001-01-01
The Euclidean compromise solution in multicriteria optimization is a solution concept that assigns to a feasible set the alternative with minimal Euclidean distance to the utopia point The purpose of this paper is to provide a characterization of the Euclidean compromise solution
Introduction to non-Euclidean geometry
Wolfe, Harold E
2012-01-01
One of the first college-level texts for elementary courses in non-Euclidean geometry, this concise, readable volume is geared toward students familiar with calculus. A full treatment of the historical background explores the centuries-long efforts to prove Euclid's parallel postulate and their triumphant conclusion. Numerous original exercises form an integral part of the book.Topics include hyperbolic plane geometry and hyperbolic plane trigonometry, applications of calculus to the solutions of some problems in hyperbolic geometry, elliptic plane geometry and trigonometry, and the consistenc
Euclidean geometry and its subgeometries
Specht, Edward John; Calkins, Keith G; Rhoads, Donald H
2015-01-01
In this monograph, the authors present a modern development of Euclidean geometry from independent axioms, using up-to-date language and providing detailed proofs. The axioms for incidence, betweenness, and plane separation are close to those of Hilbert. This is the only axiomatic treatment of Euclidean geometry that uses axioms not involving metric notions and that explores congruence and isometries by means of reflection mappings. The authors present thirteen axioms in sequence, proving as many theorems as possible at each stage and, in the process, building up subgeometries, most notably the Pasch and neutral geometries. Standard topics such as the congruence theorems for triangles, embedding the real numbers in a line, and coordinatization of the plane are included, as well as theorems of Pythagoras, Desargues, Pappas, Menelaus, and Ceva. The final chapter covers consistency and independence of axioms, as well as independence of definition properties. There are over 300 exercises; solutions to many of the...
Effects of high let radiation at the cellular level
The complete evaluation of the impact of nuclear energy technologies on human health requires: identification and characterization of hazardous agents and their effects, which is well advanced; quantitative dose-effect relations for important effects under various conditions of radiation exposure and biological variation, which needs more work but which has been advancing fairly well, particularly in experimental animal research; an understanding of the cellular and tissue mechanisms of the hazardous effects in relation to the microdosimetry of the agents, which has advanced slowly and to a relatively limited degree; and integration of the dose-effect relations and mechanistic knowledge into theories and models which are intended to be predictive for estimation of human health risks at pertinent low levels of exposure. Several theories, hypotheses or models of radiation carcinogenesis, and some for alpha radiation in particular, have been developed on the basis of dose-effect relations in the necessary attempt to predict the hazards of low levels of radiation exposure for purposes of radiation protection in advance of adequate data on dose-effect relations and mchanisms. As such these theories or models have necessarily involved strings of explicit and implicit assumptions concerning mechanisms and the nature of dose-effect relations below the dose regions at which effects have been observed. Nevertheless, they have been useful in stimulating research to test their assumptions and in assuming the interpretation of data
A positive feedback at the cellular level promotes robustness and modulation at the circuit level.
Dethier, Julie; Drion, Guillaume; Franci, Alessio; Sepulchre, Rodolphe
2015-10-01
This article highlights the role of a positive feedback gating mechanism at the cellular level in the robustness and modulation properties of rhythmic activities at the circuit level. The results are presented in the context of half-center oscillators, which are simple rhythmic circuits composed of two reciprocally connected inhibitory neuronal populations. Specifically, we focus on rhythms that rely on a particular excitability property, the postinhibitory rebound, an intrinsic cellular property that elicits transient membrane depolarization when released from hyperpolarization. Two distinct ionic currents can evoke this transient depolarization: a hyperpolarization-activated cation current and a low-threshold T-type calcium current. The presence of a slow activation is specific to the T-type calcium current and provides a slow positive feedback at the cellular level that is absent in the cation current. We show that this slow positive feedback is required to endow the network rhythm with physiological modulation and robustness properties. This study thereby identifies an essential cellular property to be retained at the network level in modeling network robustness and modulation. PMID:26311181
Hardware Euclidean Distance Transform Implementation
XIE Ying-hua; ZENG Pei-feng; TANG Li-ping
2004-01-01
Based on an efficient algorithm of Euclidean distance transform for binary images, a circuit of O(N2) size is proposed. With in-place calculation, both the intermediate data storing and the result output use the same memory with the input data. This reduces the amount of memory largely. By replacing multipliers with counters, comparators, and adders, the circuit size is further reduced and its calculation speed is improved also.
Hausdorff operators on Euclidean spaces
CHEN Jie-cheng; FAN Da-shan; WANG Si-lei
2013-01-01
Hausdorff operator is an important operator raised from the dilation on Euclidean space and rooted in the classical summability of number series and Fourier series. It is also connected to many well known operators in real and complex analysis. This article is a survey of some recent developments and extensions on the Hausdorff operator. Particularly, various boundedness properties of the Hausdorff operators, studied recently by our research group, are addressed.
Higher codimensional Euclidean helix submanifolds
Di Scala, Antonio J.; Ruiz-Hernández, Gabriel
2010-01-01
A submanifold of Rn whose tangent space makes constant angle with a fixed direction d is called a helix. Helix submanifolds are related with the eikonal PDE equation. We give a method to find every solution to the eikonal PDE on a Riemannian manifold locally. As a consequence we give a local construction of arbitrary Euclidean helix submanifolds of any dimension and codimension. Also we characterize the ruled helix submanifolds and in particular we describe those which are minimal.
Piracy on the molecular level: human herpesviruses manipulate cellular chemotaxis.
Cornaby, Caleb; Tanner, Anne; Stutz, Eric W; Poole, Brian D; Berges, Bradford K
2016-03-01
Cellular chemotaxis is important to tissue homeostasis and proper development. Human herpesvirus species influence cellular chemotaxis by regulating cellular chemokines and chemokine receptors. Herpesviruses also express various viral chemokines and chemokine receptors during infection. These changes to chemokine concentrations and receptor availability assist in the pathogenesis of herpesviruses and contribute to a variety of diseases and malignancies. By interfering with the positioning of host cells during herpesvirus infection, viral spread is assisted, latency can be established and the immune system is prevented from eradicating viral infection. PMID:26669819
Organisms exposed to suboptimal environments incur a cost of dealing with stress in terms of metabolic resources. The total amount of energy available for maintenance, growth and reproduction, based on the biochemical analysis of the energy budget, may provide a sensitive measure of stress in an organism. While the concept is clear, linking cellular or biochemical responses to the individual and population or community level remains difficult. The aim of this study was to validate, under field conditions, using cellular energy budgets [i.e. changes in glycogen-, lipid- and protein-content and mitochondrial electron transport system (ETS)] as an ecologically relevant measurement of stress by comparing these responses to physiological and organismal endpoints. Therefore, a 28-day in situ bioassay with zebra mussels (Dreissena polymorpha) was performed in an effluent-dominated stream. Five locations were selected along the pollution gradient and compared with a nearby (reference) site. Cellular Energy Allocation (CEA) served as a biomarker of cellular energetics, while Scope for Growth (SFG) indicated effects on a physiological level and Tissue Condition Index and wet tissue weight/dry tissue weight ratio were used as endpoints of organismal effects. Results indicated that energy budgets at a cellular level of biological organization provided the fastest and most sensitive response and energy budgets are a relevant currency to extrapolate cellular effects to higher levels of biological organization within the exposed mussels. - Exposure of zebra mussels along a pollution gradient has adverse effects on the cellular energy allocation, and results can be linked with higher levels of biological organization
Conformal Janus on Euclidean Sphere
Bak, Dongsu; Rey, Soo-Jong
2016-01-01
We interpret Janus as an interface in a conformal field theory and study its properties. The Janus is created by an exactly marginal operator and we study its effect on the interface conformal field theory on the Janus. We do this by utilizing the AdS/CFT correspondence. We compute the interface free energy both from leading correction to the Euclidean action in the dual gravity description and from conformal perturbation theory in the conformal field theory. We find that the two results agree each other and that the interface free energy scales precisely as expected from the conformal invariance of the Janus interface.
Euclidean Prize-collecting Steiner Forest
Bateni, MohammadHossein; Hajiaghayi, Mohammadtaghi
2009-01-01
In this paper, we consider Steiner forest and its generalizations, prize-collecting Steiner forest and k-Steiner forest, when the vertices of the input graph are points in the Euclidean plane and the lengths are Euclidean distances. First, we present a simpler analysis of the polynomial-time approximation scheme (PTAS) of Borradaile et al. [12] for the Euclidean Steiner forest problem. This is done by proving a new structural property and modifying the dynamic programming by adding a new piec...
Notes on euclidean de Sitter space
We discuss issues relating to the topology of euclidean de Sitter space. We show that in (2+1) dimensions, the euclidean continuation of the 'causal diamond', i.e. the region of spacetime accessible to a timelike observer is a three-hemisphere. However, when de Sitter entropy is computed in a 'stretched horizon' picture, then we argue that the correct euclidean topology is a solid torus. The solid torus shrinks and degenerates into a three-hemisphere as one goes from the 'stretched horizon' to the horizon, giving the euclidean continuation of the causal diamond. We finally comment on generalisation of these results to higher dimensions. (author)
Cellular level loading and heating of superparamagnetic iron oxide nanoparticles.
Kalambur, Venkat S; Longmire, Ellen K; Bischof, John C
2007-11-20
Superparamagnetic iron oxide nanoparticles (NPs) hold promise for a variety of biomedical applications due to their properties of visualization using magnetic resonance imaging (MRI), heating with radio frequency (rf), and movement in an external magnetic field. In this study, the cellular loading (uptake) mechanism of dextran- and surfactant-coated iron oxide NPs by malignant prostate tumor cells (LNCaP-Pro5) has been studied, and the feasibility of traditional rf treatment and a new laser heating method was evaluated. The kinetics of cell loading was quantified using magnetophoresis and a colorimetric assay. The results showed that loading of surfactant-coated iron oxide NPs with LNCaP-Pro5 was saturable with time (at 24 h) and extracellular concentration (11 pg Fe/cell at 0.5 mg Fe/mL), indicating that the particles are taken up by an "adsorptive endocytosis" pathway. Dextran-coated NPs, however, were taken up less efficiently (1 pg Fe/cell at 0.5 mg Fe/mL). Loading did not saturate with concentration suggesting uptake by fluid-phase endocytosis. Magnetophoresis suggests that NP-loaded cells can be held using external magnetic fields in microcirculatory flow velocities in vivo or in an appropriately designed extracorporeal circuit. Loaded cells were heated using traditional rf (260A, 357 kHz) and a new laser method (532 nm, 7 ns pulse duration, 0.03 J/pulse, 20 pulse/s). Iron oxide in water was found to absorb sufficiently strongly at 532 nm such that heating of individual NPs and thus loaded cells (1 pg Fe/cell) was effective (10 pg Fe/cell) and longer duration (30 min) when compared to laser to accomplish cell destruction (50% viability at 10 pg Fe/cell). Scaling calculations show that the pulsed laser method can lead to single-cell (loaded with NPs) treatments (200 degrees C temperature change at the surface of an individual NP) unlike traditional rf heating methods which can be used only for bulk tissue level treatments. In a mixture of normal and NP
Real-time reporting and internet-accessible cellular based coastal sea level gauge
Desai, R.G.P.; Joseph, A; Agarvadekar, Y.; Mehra, P.; Dabholkar, N.; Parab, A; Gouveia, A; Tengali, S.
A real-time sea-level reporting system utilizing exiting cellular communication infrastructure is described. Several issues involved in the implementation of internetaccessible sea-level gauge have been addressed. It is anticipated that the growth...
Human more complex than mouse at cellular level.
Alexander E Vinogradov
Full Text Available The family of transcription factors with the C2H2 zinc finger domain is expanding in the evolution of vertebrates, reaching its highest numbers in the mammals. The question arises: whether an increased amount of these transcription factors is related to embryogenesis, nervous system, pathology or more of them are expressed in individual cells? Among mammals, the primates have a more complex anatomical structure than the rodents (e.g., brain. In this work, I show that a greater number of C2H2-ZF genes are expressed in the human cells than in the mouse cells. The effect is especially pronounced for C2H2-ZF genes accompanied with the KRAB domain. The relative difference between the numbers of C2H2-ZF(-KRAB genes in the human and mouse cellular transcriptomes even exceeds their difference in the genomes (i.e. a greater subset of existing in the genome genes is expressed in the human cellular transcriptomes compared to the mouse transcriptomes. The evolutionary turnover of C2H2-ZF(-KRAB genes acts in the direction of the revealed phenomenon, i.e. gene duplication and loss enhances the difference in the relative number of C2H2-ZF(-KRAB genes between human and mouse cellular transcriptomes. A higher amount of these genes is expressed in the brain and embryonic cells (compared with other tissues, whereas a lower amount--in the cancer cells. It is specifically the C2H2-ZF transcription factors whose repertoire is poorer in the cancer and richer in the brain (other transcription factors taken together do not show this trend. These facts suggest that increase of anatomical complexity is accompanied by a more complex intracellular regulation involving these transcription factors. Malignization is associated with simplification of this regulation. These results agree with the known fact that human cells are more resistant to oncogenic transformation than mouse cells. The list of C2H2-ZF genes whose suppression might be involved in malignization is provided.
β-Amyloid pathogenesis: Chemical properties versus cellular levels
Tiwari, Manish Kumar; Kepp, Kasper Planeta
2016-01-01
Although genetic Aβ variants cause early-onset Alzheimer's disease, literature reports on Aβ properties are heterogeneous, obscuring molecular mechanisms, as illustrated by recent failures of Aβ-level targeting trials. Thus, we combined available data on Aβ levels and ratios, aggregation propensi...
Atherogenesis and iron: from epidemiology to cellular level
ViktóriaJeney
2014-05-01
Full Text Available Iron accumulates in human atherosclerotic lesions but whether it is a cause or simply a downstream consequence of the atheroma formation has been an open question for decades. According to the so called “iron hypothesis”, iron is believed to be detrimental for the cardiovascular system, thus promoting atherosclerosis development and progression. Iron, in its catalytically active form, can participate in the generation of reactive oxygen species and induce lipid-peroxidation, triggering endothelial activation, smooth muscle cell proliferation and macrophage activation; all of these processes are considered to be proatherogenic. On the other hand, the observation that hemochromatotic patients, affected by life-long iron overload, do not show any increased incidence of atherosclerosis is perceived as the most convincing evidence against the “iron hypothesis”. Epidemiological studies and data from animal models provided conflicting evidences about the role of iron in atherogenesis. Therefore more careful studies are needed in which issues like the source and the compartmentalization of iron will be addressed. This review article summarizes what we have learnt about iron and atherosclerosis from epidemiological studies, animal models and cellular systems and highlights the rather contributory than innocent role of iron in atherogenesis.
Using a Virtual Tissue Culture System to Assist Students in Understanding Life at the Cellular Level
McLauglin, Jacqueline S.; Seaquist, Stephen B.
2008-01-01
In every biology course ever taught in the nation's classrooms, and in every biology book ever published, students are taught about the "cell." The cell is as fundamental to biology as the atom is to chemistry. Truly, everything an organism does occurs fundamentally at the cellular level. Beyond memorizing the cellular definition, students are not…
Euclidean Prize-collecting Steiner Forest
Bateni, MohammadHossein
2009-01-01
In this paper, we consider Steiner forest and its generalizations, prize-collecting Steiner forest and k-Steiner forest, when the vertices of the input graph are points in the Euclidean plane and the lengths are Euclidean distances. First, we present a simpler analysis of the polynomial-time approximation scheme (PTAS) of Borradaile et al. [12] for the Euclidean Steiner forest problem. This is done by proving a new structural property and modifying the dynamic programming by adding a new piece of information to each dynamic programming state. Next we develop a PTAS for a well-motivated case, i.e., the multiplicative case, of prize-collecting and budgeted Steiner forest. The ideas used in the algorithm may have applications in design of a broad class of bicriteria PTASs. At the end, we demonstrate why PTASs for these problems can be hard in the general Euclidean case (and thus for PTASs we cannot go beyond the multiplicative case).
A Negative Mode About Euclidean Wormhole
Rubakov, V. A.; Shvedov, O. Yu.
1996-01-01
Wormholes -- solutions to the euclidean Einstein equations with non-trivial topology -- are usually assumed to make real contributions to amplitudes in quantum gravity. However, we find a negative mode among fluctuations about the Giddings-Strominger wormhole solution. Hence, the wormhole contribution to the euclidean functional integral is argued to be purely imaginary rather than real, which suggests the interpretation of the wormhole as describing the instability of a large universe agains...
A Euclidean algorithm for integer matrices
Lauritzen, Niels; Thomsen, Jesper Funch
2015-01-01
We present a Euclidean algorithm for computing a greatest common right divisor of two integer matrices. The algorithm is derived from elementary properties of finitely generated modules over the ring of integers.......We present a Euclidean algorithm for computing a greatest common right divisor of two integer matrices. The algorithm is derived from elementary properties of finitely generated modules over the ring of integers....
Classical geometry Euclidean, transformational, inversive, and projective
Leonard, I E; Liu, A C F; Tokarsky, G W
2014-01-01
Features the classical themes of geometry with plentiful applications in mathematics, education, engineering, and science Accessible and reader-friendly, Classical Geometry: Euclidean, Transformational, Inversive, and Projective introduces readers to a valuable discipline that is crucial to understanding bothspatial relationships and logical reasoning. Focusing on the development of geometric intuitionwhile avoiding the axiomatic method, a problem solving approach is encouraged throughout. The book is strategically divided into three sections: Part One focuses on Euclidean geometry, which p
The Euclidean distribution of Fast Radio Bursts
Oppermann, Niels; Connor, Liam; Pen, Ue-Li
2016-01-01
We investigate whether current data on the distribution of observed flux densities of Fast Radio Bursts (FRBs) are consistent with a constant source density in Euclidean space. We use the number of FRBs detected in two surveys with different characteristics along with the observed signal-to-noise ratios of the detected FRBs in a formalism similar to a V/V_max-test to constrain the distribution of flux densities. We find consistency between the data and a Euclidean distribution. Any extension ...
Non-Euclidean-normed Statistical Mechanics
Livadiotis, George
2016-03-01
This analysis introduces a possible generalization of Statistical Mechanics within the framework of non-Euclidean metrics induced by the Lp norms. The internal energy is interpreted by the non-Euclidean Lp-normed expectation value of a given energy spectrum. The presented non-Euclidean adaptation of Statistical Mechanics involves finding the stationary probability distribution in the Canonical Ensemble by maximizing the Boltzmann-Gibbs and Tsallis entropy under the constraint of internal energy. The derived non-Euclidean Canonical probability distributions are respectively given by an exponential, and by a q-deformed exponential, of a power-law dependence on energy states. The case of the continuous energy spectrum is thoroughly examined. The Canonical probability distribution is analytically calculated for a power-law density of energy. The relevant non-Euclidean-normed kappa distribution is also derived. This analysis exposes the possible values of the q- or κ-indices, which are strictly limited to certain ranges, depending on the given Lp-norm. The equipartition of energy in each degree of freedom and the extensivity of the internal energy, are also shown. Surprisingly, the physical temperature coincides with the kinetically defined temperature, similar to the Euclidean case. Finally, the connection with thermodynamics arises through the well-known standard classical formalisms.
A Euclidean bridge to the relativistic constituent quark model
Hobbs, T J; Miller, Gerald A
2016-01-01
${\\bf Background}$ Knowledge of nucleon structure is today ever more of a precision science, with heightened theoretical and experimental activity expected in coming years. At the same time, a persistent gap lingers between theoretical approaches grounded in Euclidean methods (e.g., lattice QCD, Dyson-Schwinger Equations [DSEs]) as opposed to traditional Minkowski field theories (such as light-front constituent quark models). ${\\bf Purpose}$ Seeking to bridge these complementary worldviews, we explore the potential of a Euclidean constituent quark model (ECQM). This formalism enables us to study the gluonic dressing of the quark-level axial-vector vertex, which we undertake as a test of the framework. ${\\bf Method}$ To access its indispensable elements with a minimum of inessential detail, we develop our ECQM using the simplified quark $+$ scalar diquark picture of the nucleon. We construct a hyperspherical formalism involving polynomial expansions of diquark propagators to marry our ECQM with the results of ...
Information metric and Euclidean Janus correspondence
Dongsu Bak
2016-05-01
Full Text Available We consider the quantum information metric of a family of CFTs perturbed by an exactly marginal operator, which has the dual description of the Euclidean Janus geometries. We first clarify its two dimensional case dual to the three dimensional Janus geometry, which recently appeared in arXiv:1507.07555 [2]. We generalize this correspondence to higher dimensions and get a precise agreement between the both sides. We also show that the mixed-state information metric of the same family of CFTs has a dual description in the Euclidean version of the Janus time-dependent black hole geometry.
Information metric and Euclidean Janus corresponence
Bak, Dongsu
2015-01-01
We consider the quantum information metric of a family of CFTs perturbed by an exactly marginal operator, which has the dual description of the Euclidean Janus geometries. We first review its two dimensional case dual to the three dimensional Janus geometry, which is recently proposed in arXiv:1507.07555. We generalize this correspondence to higher dimensions and get a precise agreement of the both sides. We also propose that the mixed-state information metric of the same family of CFTs is dual to the Euclidean version of the Janus time-dependent black hole geometry.
Information metric and Euclidean Janus correspondence
Bak, Dongsu
2016-05-01
We consider the quantum information metric of a family of CFTs perturbed by an exactly marginal operator, which has the dual description of the Euclidean Janus geometries. We first clarify its two dimensional case dual to the three dimensional Janus geometry, which recently appeared in arxiv:arXiv:1507.07555[2]. We generalize this correspondence to higher dimensions and get a precise agreement between the both sides. We also show that the mixed-state information metric of the same family of CFTs has a dual description in the Euclidean version of the Janus time-dependent black hole geometry.
The level of cellular diacylglycerol (DG), measured as DG-dependent incorporation of labelled cytidine diphosphocholine (CDP-choline) into phosphatidylcholine (PC) was studied in the spinal cord regions after 25 min ischemia and 60 min of recirculation. Ischemia alone significantly increased the level of cellular DG in the white matter, whereas that found in the dorsal horns and intermediate zone was significantly lower. A decreased incorporation of CDP-choline into PC of the white and gray matter was found during recirculation. (authors)
Majorization in Euclidean Geometry and Beyond
Fiedler, Miroslav
2015-01-01
Roč. 466, 1 February (2015), s. 233-240. ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : Majorization * Doubly stochastic matrix * Euclidean simplex * Star * Regular simplex * Volume of a simplex Subject RIV: BA - General Mathematics Impact factor: 0.939, year: 2014
F4 Algorithm For Euclidean Rings
Sadiq, Afshan
2010-01-01
This short note is the generalization of Faugere F4-algorithm for polynomial rings with coefficients in Euclidean rings. This algorithm computes successively a Groebner basis replacing the reduction of one single s-polynomial in Buchberger's algorithm by the simultaneous reduction of several polynomials.
ON SPACELIKE AUSTERE SUBMANIFOLDS IN PSEUDO-EUCLIDEAN SPACE
Dong Yuxin; Han Yingbo
2011-01-01
In this article, we construct some spacelike austere submanifolds in pseduo- Euclidean spaces. We also get some indefinite special Lagrangian submanifolds by con- structing twisted normal bundle of spacelike austere submanifolds in pseduo-Euclidean spaces.
Zhang, Hai-Lin; Zang, Yi; Xie, Juan; Li, Jia; Chen, Guo-Rong; He, Xiao-Peng; Tian, He
2014-07-01
A tetrameric N-acetyl galactosaminyl (GalNAc) peptidomimetic was constructed by N-acetylation of repeating proline-based hydroxamic acid units, followed by a convergent `click chemistry' coupling. This novel glycopeptidomimetic was determined to effectively antagonize the interaction between a transmembrane hepatic lectin and GalNAc on the cellular level.
Quantum Biology at the Cellular Level - elements of the research program
Bordonaro, Michael; Ogryzko, Vasily
2013-01-01
Quantum Biology is emerging as a new field at the intersection between fundamental physics and biology, promising novel insights into the nature and origin of biological order. We discuss several elements of QBCL (Quantum Biology at Cellular Level), a research program designed to extend the reach of quantum concepts to higher than molecular levels of biological organization. Key words. decoherence, macroscopic superpositions, basis-dependence, formal superposition, non-classical correlations,...
ELF (extremely-low-frequency) field interactions at the animal, tissue and cellular levels
Tenforde, T.S.
1990-10-01
A description is given of the fundamental physical properties of extremely-low-frequency (ELF) electromagnetic fields, and the mechanisms through which these fields interact with the human body at a macroscopic level. Biological responses to ELF fields at the tissue, cellular and molecular levels are summarized, including new evidence that ELF field exposure produces alterations in gene expression and the cytoplasmic concentrations of specific proteins.
Cellular burdens and biological effects on tissue level caused by inhaled radon progenies
Madas, Balázs G; Farkas, Árpád; Szőke, István
2014-01-01
In the case of radon exposure, the spatial distribution of deposited radioactive particles is highly inhomogeneous in the central airways. The objective of this research is to investigate the consequences of this heterogeneity regarding cellular burdens in the bronchial epithelium and to study the possible biological effects on tissue level. Applying a computational fluid dynamics program, the deposition distribution of inhaled radon daughters has been determined in a bronchial airway model for 23 minutes of work in the New Mexico uranium mine corresponding to 0.0129 WLM exposure. A numerical epithelium model based on experimental data has been utilized in order to quantify cellular hits and doses. Finally, a carcinogenesis model considering cell death induced cell cycle shortening has been applied to assess the biological responses. Computations present, that cellular dose may reach 1.5 Gy, which is several orders of magnitude higher than tissue dose. The results are in agreement with the histological findin...
Lee, Irene; Berdis, Anthony J
2016-01-01
Historically, the study of proteins has relied heavily on characterizing the activity of a single purified protein isolated from other cellular components. This classic approach allowed scientists to unambiguously define the intrinsic kinetic and chemical properties of that protein. The ultimate hope was to extrapolate this information toward understanding how the enzyme or receptor behaves within its native cellular context. These types of detailed in vitro analyses were necessary to reduce the innate complexities of measuring the singular activity and biochemical properties of a specific enzyme without interference from other enzymes and potential competing substrates. However, recent developments in fields encompassing cell biology, molecular imaging, and chemical biology now provide the unique chemical tools and instrumentation to study protein structure, function, and regulation in their native cellular environment. These advancements provide the foundation for a new field, coined physiological enzymology, which quantifies the function and regulation of enzymes and proteins at the cellular level. In this Special Edition, we explore the area of Physiological Enzymology and Protein Function through a series of review articles that focus on the tools and techniques used to measure the cellular activity of proteins inside living cells. This article is part of a Special Issue entitled: Physiological Enzymology and Protein Functions. PMID:26277093
Euclidean wormholes with minimally coupled scalar fields
A detailed study of quantum and semiclassical Euclidean wormholes for Einstein's theory with a minimally coupled scalar field has been performed for a class of potentials. Massless, constant, massive (quadratic in the scalar field) and inverse (linear) potentials admit the Hawking and Page wormhole boundary condition both in the classically forbidden and allowed regions. An inverse quartic potential has been found to exhibit a semiclassical wormhole configuration. Classical wormholes under a suitable back-reaction leading to a finite radius of the throat, where the strong energy condition is satisfied, have been found for the zero, constant, quadratic and exponential potentials. Treating such classical Euclidean wormholes as an initial condition, a late stage of cosmological evolution has been found to remain unaltered from standard Friedmann cosmology, except for the constant potential which under the back-reaction produces a term like a negative cosmological constant. (paper)
The Euclidean distribution of fast radio bursts
Oppermann, Niels; Connor, Liam D.; Pen, Ue-Li
2016-09-01
We investigate whether current data on the distribution of observed flux densities of fast radio bursts (FRBs) are consistent with a constant source density in Euclidean space. We use the number of FRBs detected in two surveys with different characteristics along with the observed signal-to-noise ratios of the detected FRBs in a formalism similar to a V/Vmax-test to constrain the distribution of flux densities. We find consistency between the data and a Euclidean distribution. Any extension of this model is therefore not data-driven and needs to be motivated separately. As a byproduct we also obtain new improved limits for the FRB rate at 1.4 GHz, which had not been constrained in this way before.
The Euclidean distribution of Fast Radio Bursts
Oppermann, Niels; Pen, Ue-Li
2016-01-01
We investigate whether current data on the distribution of observed flux densities of Fast Radio Bursts (FRBs) are consistent with a constant source density in Euclidean space. We use the number of FRBs detected in two surveys with different characteristics along with the observed signal-to-noise ratios of the detected FRBs in a formalism similar to a V/V_max-test to constrain the distribution of flux densities. We find consistency between the data and a Euclidean distribution. Any extension of this model is therefore not data-driven and needs to be motivated separately. As a byproduct we also obtain new improved limits for the FRB rate at 1.4 GHz, which had not been constrained in this way before.
Matrices and Graphs in Euclidean Geometry
Fiedler, Miroslav
2005-01-01
Roč. 14, - (2005), s. 51-58. E-ISSN 1081-3810 R&D Projects: GA AV ČR IAA1030302 Institutional research plan: CEZ:AV0Z10300504 Keywords : Euclidean space * Gram matrix * biorthogonal bases * simplex * interior angle * Steiner circumscribed ellipsoid * right simplex Subject RIV: BA - General Mathematics http://www.math.technion.ac.il/iic/ela/ela-articles/14.html
Euclidean Approach for Entropy of Black Shells
S., J Robel Arenas
2016-01-01
We introduce the concept of black shell, consisting on a massive thin spherical shell contracting toward its gravitational radius from the point of view of an external observer far from the shell, in order to effectively model the gravitational collapse. Considering complementary description of entanglement entropy of a black shell and according to Gibbons-Hawking Euclidean approach, we calculate the Bekenstein-Hawking entropy retrieving horizon integral and discarding boundary at infinity.
Euclidean Supergravity in Terms of Dirac Eigenvalues
Vancea, I V
1998-01-01
It has been recently shown by Landi and Rovelli that the eigenvalues of the Dirac operator can be considered as dynamical variables of Euclidean gravity. The purpose of this paper is to explore the possibility that the eigenvalues of the Dirac operator play the same role in the case of supergravity. It is shown that some constraints on the covariant phase space as well as on the eigenspinors must be imposed to this end.
Euclidean Supergravity in Terms of Dirac Eigenvalues
Vancea, I. V.
1997-01-01
It has been recently shown that the eigenvalues of the Dirac operator can be considered as dynamical variables of Euclidean gravity. The purpose of this paper is to explore the possiblity that the eigenvalues of the Dirac operator might play the same role in the case of supergravity. It is shown that for this purpose some primary constraints on covariant phase space as well as secondary constraints on the eigenspinors must be imposed. The validity of primary constraints under covariant transp...
Simple Euclidean arrangements with one (>=5)-gon
Leaños, Jesus; Rivera-Martinez, Luis Manuel
2010-01-01
Let L be a simple Euclidean arrangement of n pseudolines. It is shown that if L has exactly one (>=5)=gon P, and k is the number of edges of P that are adjacent to an unbounded cell of the subarrangement of L induced by the pseudolines in P, then L has exactly n-k triangles and k+n(n-5)/2 quadrilaterals. We also prove that if each pseudoline of L is adjacent to P then L is stretchable.
The sharp quantitative Euclidean concentration inequality
Figalli, Alessio; Maggi, Francesco; Mooney, Connor
2016-01-01
The Euclidean concentration inequality states that, among sets with fixed volume, balls have $r$-neighborhoods of minimal volume for every $r>0$. On an arbitrary set, the deviation of this volume growth from that of a ball is shown to control the square of the volume of the symmetric difference between the set and a ball. This estimate is sharp and includes, as a special case, the sharp quantitative isoperimetric inequality proved in \\cite{fuscomaggipratelli}.
Euclidean fields: vector mesons and photons
Free transverse vector fields of mass >= 0 are studied. The model is related to the usual free vector meson and electromagnetic quantum field theories by extension of the field operators from transverse to arbitrary test functions. The one-particle states in transverse gauge and their localization are described. Reflexion positivity is proved and derived are free Feynman-Kac-Nelson formulas. An Euclidean approach to a photon field in a spherical world using dilatation covariance and inversions is given
Rodríguez Velásquez, Javier Oswaldo
2014-01-01
Full Text Available Background: Pathological interpretation of cellular form in cervical cytology is very important for preven- tion of cervical cancer. The methods most frequently used for assessment of this test have reproducibility and inter-observer variability problems. Objective: To make fractal and Euclidean measure- ments to mathematically diagnose normal and pre- malignant cells of cervical squamous epithelium. Methodology: 21 cells with normal, ASCUS or LSIL diagnosis according to the Bethesda system were assessed. Fractal and Euclidean geometric measures of three mathematical objects were calculated: cyto- plasm, nucleus and whole cell. Mathematical propor- tions between these measurements were calculated in order to compare them with conventional classification methods. Results: It was found that the nuclear border measures calculated with the 2-pixel grill and the surface measures could mathematically and objectively differentiate normal cells from the pre-malignant ones (ASCUS and LSIL. Conclusions: An objective and reproducible diagnos- tic method was developed; it allows to identify the evolution towards malignant cellular states based on simultaneous fractal and Euclidean measures, estab- lishing the severity level of ASCUS and LSIL cells.
Foundation of Euclidean and non-Euclidean geometries according to F. Klein
Redei, L; Stark, M
1968-01-01
Foundation of Euclidean and Non-Euclidean Geometries according to F. Klein aims to remedy the deficiency in geometry so that the ideas of F. Klein obtain the place they merit in the literature of mathematics.This book discusses the axioms of betweenness, lattice of linear subspaces, generalization of the notion of space, and coplanar Desargues configurations. The central collineations of the plane, fundamental theorem of projective geometry, and lines perpendicular to a proper plane are also elaborated. This text likewise covers the axioms of motion, basic projective configurations, properties
Regulatory nexus of synthesis and degradation deciphers cellular Nrf2 expression levels.
Suzuki, Takafumi; Shibata, Tatsuhiro; Takaya, Kai; Shiraishi, Kouya; Kohno, Takashi; Kunitoh, Hideo; Tsuta, Koji; Furuta, Koh; Goto, Koichi; Hosoda, Fumie; Sakamoto, Hiromi; Motohashi, Hozumi; Yamamoto, Masayuki
2013-06-01
Transcription factor Nrf2 (NF-E2-related factor 2) is essential for oxidative and electrophilic stress responses. While it has been well characterized that Nrf2 activity is tightly regulated at the protein level through proteasomal degradation via Keap1 (Kelch-like ECH-associated protein 1)-mediated ubiquitination, not much attention has been paid to the supply side of Nrf2, especially regulation of Nrf2 gene transcription. Here we report that manipulation of Nrf2 transcription is effective in changing the final Nrf2 protein level and activity of cellular defense against oxidative stress even in the presence of Keap1 and under efficient Nrf2 degradation, determined using genetically engineered mouse models. In excellent agreement with this finding, we found that minor A/A homozygotes of a single nucleotide polymorphism (SNP) in the human NRF2 upstream promoter region (rs6721961) exhibited significantly diminished NRF2 gene expression and, consequently, an increased risk of lung cancer, especially those who had ever smoked. Our results support the notion that in addition to control over proteasomal degradation and derepression from degradation/repression, the transcriptional level of the Nrf2 gene acts as another important regulatory point to define cellular Nrf2 levels. These results thus verify the critical importance of human SNPs that influence the levels of transcription of the NRF2 gene for future personalized medicine. PMID:23572560
One-micron resolution optical coherence tomography (OCT) in vivo for cellular level imaging
Cui, Dongyao; Liu, Xinyu; Zhang, Jing; Yu, Xiaojun; Sun, Ding; Luo, Yuemei; Gu, Jun; Shum, Ping; Liu, Linbo
2015-03-01
We developed a spectral domain OCT system combining two NIR, CW light sources of different spectral range. Its resolving power is validated by visualizing the cellular structures of zebra fish larvae in vivo. An NIR extended illumination from 755-1100 nm is achieved. The axial resolution is 1.27 μm in air, corresponding to 0.93μm in tissue (n=1.36), which is the highest axial resolution using NIR, CW laser sources up to date to the best of our knowledge. In vivo imaging is conducted to demonstrate the resolving power of proposed one-micron resolution OCT system. The top and bottom surfaces of individual disk-like red blood cell is reliably visualized, as well as flat, spindle shaped endothelial cells lining along the luminal surface of the blood vessel wall. This study provides a viable solution for cellular and subcellular level OCT imaging system which is also very competitive in cost.
The effect of cellular carotenoid levels in micrococcus luteus on resistance to gamma radiation
In the present study, a biological system was developed to link the cellular carotenoid levels to Gamma radiation resistance in bacteria for the frst time. thus, in a non-photosynrhetic bacterium, in Micrococcus Luteus an inverse relationship was found between the increase in diphenylamine (DPA) concentration (5.25 μg/ml culture) and the polar cellular carotenoid pigments (C-45 and C-50 carotenoids and their glucosides). It was also found that irradiation of cells with different carotenoid concentrations with doses of γ-radiation in the range of (0.2500 gray) under oxic, air and hypoxic conditions showed that carotenoid pigments offer no significant protection as they usually do in case of visible light. (author).15 refs., 5 figs., 3 tabs
Stability Issues in Euclidean Quantum Gravity
Modanese, G.
1998-01-01
It is known that the action of Euclidean Einstein gravity is not bounded from below and that the metric of flat space does not correspond to a minimum of the action. Nevertheless, perturbation theory about flat space works well. The deep dynamical reasons for this reside in the non perturbative behaviour of the system and have been clarified in part by numerical simulations. Several open issues remain. We treat in particular those zero modes of the action for which R(x) is not identically zer...
Euclidean Quantum Mechanics and Universal Nonlinear Filtering
Bhashyam Balaji
2009-02-01
Full Text Available An important problem in applied science is the continuous nonlinear filtering problem, i.e., the estimation of a Langevin state that is observed indirectly. In this paper, it is shown that Euclidean quantum mechanics is closely related to the continuous nonlinear filtering problem. The key is the configuration space Feynman path integral representation of the fundamental solution of a Fokker-Planck type of equation termed the Yau Equation of continuous-continuous filtering. A corollary is the equivalence between nonlinear filtering problem and a time-varying Schr¨odinger equation.
Information metric and Euclidean Janus correspondence
Dongsu Bak
2016-01-01
We consider the quantum information metric of a family of CFTs perturbed by an exactly marginal operator, which has the dual description of the Euclidean Janus geometries. We first clarify its two dimensional case dual to the three dimensional Janus geometry, which recently appeared in arXiv:1507.07555 [2] . We generalize this correspondence to higher dimensions and get a precise agreement between the both sides. We also show that the mixed-state information metric of the same family of CFTs ...
Exploring Concepts of Geometry not Euclidean
Luiz Ambrozi
2016-02-01
Full Text Available With this article we intend to propose different situations of teaching and learning, how they can be applied in schools, mediated by the use of concrete materials and Geogebra software, emphasizing the use of technology in the classroom, that this proposal has the role of assisting in the conceptualization and identification of elements of non-Euclidean geometry. In addition, this short course is designed to be a time of current and continuing education for teachers, with activities to be developed with dynamic geometry and based on the theory of Conceptual Fields of Vergnaud.
Euclidean Quantum Mechanics and Universal Nonlinear Filtering
Balaji, Bhashyam
2008-01-01
An important problem in applied science is the continuous nonlinear filtering problem, i.e., the estimation of a Langevin state that is observed indirectly. In this paper, it is shown that Euclidean quantum mechanics is closely related to the continuous nonlinear filtering problem. The key is the configuration space Feynman path integral representation of the fundamental solution of a Fokker-Planck type of equation termed the Yau Equation of continuous-continuous filtering. A corollary is the equivalence between nonlinear filtering problem and a time-varying Schr\\"odinger equation.
Non-Euclidean Geometry and Gravitation
Stavroulakis N.
2006-04-01
Full Text Available A great deal of misunderstandings and mathematical errors are involved in the currently accepted theory of the gravitational field generated by an isotropic spherical mass. The purpose of the present paper is to provide a short account of the rigorous mathematical theory and exhibit a new formulation of the problem. The solution of the corresponding equations of gravitation points out several new and unusual features of the stationary gravitational field which are related to the non-Euclidean structure of the space. Moreover it precludes the black hole from being a mathematical and physical notion.
Manshian, Bella B.; Munck, Sebastian; Agostinis, Patrizia; Himmelreich, Uwe; Soenen, Stefaan J.
2015-09-01
A mechanistic understanding of nanomaterial (NM) interaction with biological environments is pivotal for the safe transition from basic science to applied nanomedicine. NM exposure results in varying levels of internalized NM in different neighboring cells, due to variances in cell size, cell cycle phase and NM agglomeration. Using high-content analysis, we investigated the cytotoxic effects of fluorescent quantum dots on cultured cells, where all effects were correlated with the concentration of NMs at the single cell level. Upon binning the single cell data into different categories related to NM concentration, this study demonstrates, for the first time, that quantum dots activate both cytoprotective and cytotoxic mechanisms, resulting in a zero net result on the overall cell population, yet with significant effects in cells with higher cellular NM levels. Our results suggest that future NM cytotoxicity studies should correlate NM toxicity with cellular NM numbers on the single cell level, as conflicting mechanisms in particular cell subpopulations are commonly overlooked using classical toxicological methods.
Statistical mechanics, gravity, and Euclidean theory
A review of computations of free energy for Gibbs states on stationary but not static gravitational and gauge backgrounds is given. On these backgrounds wave equations for free fields are reduced to eigenvalue problems which depend non-linearly on the spectral parameter. We present a method to deal with such problems. In particular, we demonstrate how some results of the spectral theory of second-order elliptic operators, such as heat kernel asymptotics, can be extended to a class of non-linear spectral problems. The method is used to trace down the relation between the canonical definition of the free energy based on summation over the modes and the covariant definition given in Euclidean quantum gravity. As an application, high-temperature asymptotics of the free energy and of the thermal part of the stress-energy tensor in the presence of rotation are derived. We also discuss statistical mechanics in the presence of Killing horizons where canonical and Euclidean theories are related in a non-trivial way
Aris Wijayanti
2016-01-01
Full Text Available Identification of a retinal biometric identification methods with low error rate due to the unique patterns in the retina of blood vessels behind the retina. These patterns can be used as training data for the recognition system is then used for comparison when the identification is done. This study aims to identify the image of the human eye retina, either the left or right side, using image processing techniques and measuring the normalized Euclidean distance. So far, research on biometric systems, particularly with the object of the eye's retina, the eye is done at the owner from the owner's eyes with diverse backgrounds, such as the Messidor database. In this study created a system that can recognize the retinal image using the transformation Haar short waves by measuring the normalized Euclidean distance. Retinal image will be the initial pretreatment process of changing the original image into a gray image, which is then performed using the Haar wavelet feature extraction to obtain the energy that will be used for the normalization of the Euclidean distance, so that the process of recognition by Euclidean values are compared. Testing is done using eye retinal image database taken from Messidor many as 100 of the 300 images taken at random were then stored in a database, the database is one of 100 images stored, the database of 100 images stored 2, and 3 as many as 100 images database stored. Of the best database testing should be done as much as 6 levels of decomposition levels. From the test results have identified the recognition accuracy rate of up to 98%. The greatest degree of familiarity is level 1 that is equal to 98%. Followed usage by 80% level 2, level 3 is 59%, level 4 is 47%, level 5 is 45% and the lowest is the last level 6 that is equal to 37%. Keywords: Retinal image; Database; Euclidean normalized; Haar Wavelet
Metabolically active portion of fat-free mass: a cellular body composition level modeling analysis
Wang, ZiMian; Heshka, Stanley; Wang, Jack; Gallagher, Dympna; Deurenberg, Paul; Chen, Zhao; Heymsfield, Steven B
2006-01-01
The proportion of fat-free mass (FFM) as body cell mass (BCM) is highly related to whole body resting energy expenditure. However, the magnitude of BCM/FFM may have been underestimated in previous studies. This is because Moore’s equation [BCM (kg) =0.00833 × total body potassium (in mmol)], which was used to predict BCM, underestimates BCM by ~ %. The aims of the present study were to develop a theoretical BCM/FFM model at the cellular level and to explore the influences of sex, age, and adi...
Regan, Lynne; Hinrichsen, Michael R; Oi, Curran
2016-05-01
All diseases can be fundamentally viewed as the result of malfunctioning cellular pathways. Protein engineering offers the potential to develop new tools that will allow these dysfunctional pathways to be better understood, in addition to potentially providing new routes to restore proper function. Here we discuss different approaches that can be used to change the intracellular activity of a protein by intervening at the protein level: targeted protein sequestration, protein recruitment, protein degradation, and selective inhibition of binding interfaces. The potential of each of these tools to be developed into effective therapeutic treatments will also be discussed, along with any major barriers that currently block their translation into the clinic. PMID:27031866
Supersymmetric solutions to Euclidean Romans supergravity
Alday, Luis F.; Fluder, Martin; Gregory, Carolina Matte; Richmond, Paul; Sparks, James
2016-02-01
We study Euclidean Romans supergravity in six dimensions with a non-trivial Abelian R-symmetry gauge field. We show that supersymmetric solutions are in one-to-one correspondence with solutions to a set of differential constraints on an SU(2) structure. As an application of our results we (i) show that this structure reduces at a conformal boundary to the five-dimensional rigid supersymmetric geometry previously studied by the authors, (ii) find a general expression for the holographic dual of the VEV of a BPS Wilson loop, matching an exact field theory computation, (iii) construct holographic duals to squashed Sasaki-Einstein backgrounds, again matching to a field theory computation, and (iv) find new analytic solutions.
Cosmological Landscape and Euclidean Quantum Gravity
Barvinsky, A O
2007-01-01
Quantum creation of the universe is described by the {\\em density matrix} defined by the Euclidean path integral. This yields an ensemble of universes -- a cosmological landscape -- in a mixed quasi-thermal state which is shown to be dynamically more preferable than the pure quantum state of the Hartle-Hawking type. The latter is suppressed by the infinitely large positive action of its instanton, generated by the conformal anomaly of quantum matter. The Hartle-Hawking instantons can be regarded as posing initial conditions for Starobinsky solutions of the anomaly driven deSitter expansion, which are thus dynamically eliminated by infrared effects of quantum gravity. The resulting landscape of hot universes treated within the cosmological bootstrap (the self-consistent back reaction of quantum matter) turns out to be limited to a bounded range of the cosmological constant, which rules out a well-known infrared catastrophe of the vanishing cosmological constant and suggests an ultimate solution to the problem ...
DOMINANT EUCLIDEAN CONFIGURATIONS FOR ALL N
Bardakci, K.; Caldi, D.G.; Neuberger, H.
1980-04-01
The authors identify a class of Euclidean configurations which appear to be dominant in the functional integral of the CP{sup N-1} models. These configurations are point-like topological excitations, and they may be viewed as constituents of instantons, although they are defined independently of instantons through a continuum duality transformation. They show not only that these configurations survive as N {yields} {infinity}, but that in the plasma phase they are responsible for the effects encountered within the 1/N expansion - confinement, {theta}-dependence, and dynamical mass generation. They also discuss the possible types of plasma phase for a statistical mechanical model of the interacting excitations. Possible generalization to QCD is briefly discussed.
Euclidean supergravity in terms of Dirac eigenvalues
Vancea, Ion V.
1998-08-01
It has been recently shown that the eigenvalues of the Dirac operator can be considered as dynamical variables of Euclidean gravity. The purpose of this paper is to explore the possibility that the eigenvalues of the Dirac operator might play the same role in the case of supergravity. It is shown that for this purpose some primary constraints on covariant phase space as well as secondary constraints on the eigenspinors must be imposed. The validity of primary constraints under covariant transport is further analyzed. It is shown that in this case restrictions on the tangent bundle and on the spinor bundle of spacetime arise. The form of these restrictions is determined under some simplifying assumptions. It is also shown that manifolds with flat curvature of tangent bundle and spinor bundle satisfy these restrictions and thus they support the Dirac eigenvalues as global observables.
Smoothed analysis of partitioning algorithms for Euclidean functionals
Bläser, Markus; Manthey, Bodo; Rao, B.V. Raghavendra; Dehne, F.; Iacono, J.; Sack, J.-R.
2011-01-01
Euclidean optimization problems such as TSP and minimum-length matching admit fast partitioning algorithms that compute near-optimal solutions on typical instances. We develop a general framework for the application of smoothed analysis to partitioning algorithms for Euclidean optimization problems.
Highlights: •CR decreases total ROS and mitochondrial superoxide during the chronological aging. •CR does not affect the levels of oxidative damage on protein and DNA. •CR contributes extension of chronological lifespan by maintenance of ATP level -- Abstract: The free radical theory of aging emphasizes cumulative oxidative damage in the genome and intracellular proteins due to reactive oxygen species (ROS), which is a major cause for aging. Caloric restriction (CR) has been known as a representative treatment that prevents aging; however, its mechanism of action remains elusive. Here, we show that CR extends the chronological lifespan (CLS) of budding yeast by maintaining cellular energy levels. CR reduced the generation of total ROS and mitochondrial superoxide; however, CR did not reduce the oxidative damage in proteins and DNA. Subsequently, calorie-restricted yeast had higher mitochondrial membrane potential (MMP), and it sustained consistent ATP levels during the process of chronological aging. Our results suggest that CR extends the survival of the chronologically aged cells by improving the efficiency of energy metabolism for the maintenance of the ATP level rather than reducing the global oxidative damage of proteins and DNA
Choi, Joon-Seok; Lee, Cheol-Koo, E-mail: cklee2005@korea.ac.kr
2013-09-13
Highlights: •CR decreases total ROS and mitochondrial superoxide during the chronological aging. •CR does not affect the levels of oxidative damage on protein and DNA. •CR contributes extension of chronological lifespan by maintenance of ATP level -- Abstract: The free radical theory of aging emphasizes cumulative oxidative damage in the genome and intracellular proteins due to reactive oxygen species (ROS), which is a major cause for aging. Caloric restriction (CR) has been known as a representative treatment that prevents aging; however, its mechanism of action remains elusive. Here, we show that CR extends the chronological lifespan (CLS) of budding yeast by maintaining cellular energy levels. CR reduced the generation of total ROS and mitochondrial superoxide; however, CR did not reduce the oxidative damage in proteins and DNA. Subsequently, calorie-restricted yeast had higher mitochondrial membrane potential (MMP), and it sustained consistent ATP levels during the process of chronological aging. Our results suggest that CR extends the survival of the chronologically aged cells by improving the efficiency of energy metabolism for the maintenance of the ATP level rather than reducing the global oxidative damage of proteins and DNA.
Wolbachia-mediated resistance to dengue virus infection and death at the cellular level.
Francesca D Frentiu
Full Text Available BACKGROUND: Dengue is currently the most important arthropod-borne viral disease of humans. Recent work has shown dengue virus displays limited replication in its primary vector, the mosquito Aedes aegypti, when the insect harbors the endosymbiotic bacterium Wolbachia pipientis. Wolbachia-mediated inhibition of virus replication may lead to novel methods of arboviral control, yet the functional and cellular mechanisms that underpin it are unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using paired Wolbachia-infected and uninfected Aedes-derived cell lines and dengue virus, we confirm the phenomenon of viral inhibition at the cellular level. Although Wolbachia imposes a fitness cost to cells via reduced proliferation, it also provides a significant degree of protection from virus-induced mortality. The extent of viral inhibition is related to the density of Wolbachia per cell, with highly infected cell lines showing almost complete protection from dengue infection and dramatically reduced virus titers compared to lines not infected with the bacteria. CONCLUSIONS/SIGNIFICANCE: We have shown that cells infected with Wolbachia display inhibition of dengue virus replication, that the extent of inhibition is related to bacterial density and that Wolbachia infection, although costly, will provide a fitness benefit in some circumstances. Our results parallel findings in mosquitoes and flies, indicating that cell line models will provide useful and experimentally tractable models to study the mechanisms underlying Wolbachia-mediated protection from viruses.
Nathan J. Lanning
2014-05-01
Full Text Available Altered cellular bioenergetics and mitochondrial function are major features of several diseases, including cancer, diabetes, and neurodegenerative disorders. Given this important link to human health, we sought to define proteins within mitochondria that are critical for maintaining homeostatic ATP levels. We screened an RNAi library targeting >1,000 nuclear-encoded genes whose protein products localize to the mitochondria in multiple metabolic conditions in order to examine their effects on cellular ATP levels. We identified a mechanism by which electron transport chain (ETC perturbation under glycolytic conditions increased ATP production through enhanced glycolytic flux, thereby highlighting the cellular potential for metabolic plasticity. Additionally, we identified a mitochondrial adenylate kinase (AK4 that regulates cellular ATP levels and AMPK signaling and whose expression significantly correlates with glioma patient survival. This study maps the bioenergetic landscape of >1,000 mitochondrial proteins in the context of varied metabolic substrates and begins to link key metabolic genes with clinical outcome.
Human metapneumovirus inhibits IFN-β signaling by downregulating Jak1 and Tyk2 cellular levels.
Junping Ren
Full Text Available Human metapneumovirus (hMPV, a leading cause of respiratory tract infections in infants, inhibits type I interferon (IFN signaling by an unidentified mechanism. In this study, we showed that infection of airway epithelial cells with hMPV decreased cellular level of Janus tyrosine kinase (Jak1 and tyrosine kinase 2 (Tyk2, due to enhanced proteosomal degradation and reduced gene transcription. In addition, hMPV infection also reduced the surface expression of type I IFN receptor (IFNAR. These inhibitory mechanisms are different from the ones employed by respiratory syncytial virus (RSV, which does not affect Jak1, Tyk2 or IFNAR expression, but degrades downstream signal transducer and activator of transcription proteins 2 (STAT2, although both viruses are pneumoviruses belonging to the Paramyxoviridae family. Our study identifies a novel mechanism by which hMPV inhibits STAT1 and 2 activation, ultimately leading to viral evasion of host IFN responses.
Ozcan, H. Kurtulus; Bilgili, Erdem; Sahin, Ulku; Ucan, O. Nuri; Bayat, Cuma
2007-09-01
Tropospheric ozone concentrations, which are an important air pollutant, are modeled by the use of an artificial intelligence structure. Data obtained from air pollution measurement stations in the city of Istanbul are utilized in constituting the model. A supervised algorithm for the evaluation of ozone concentration using a genetically trained multi-level cellular neural network (ML-CNN) is introduced, developed, and applied to real data. A genetic algorithm is used in the optimization of CNN templates. The model results and the actual measurement results are compared and statistically evaluated. It is observed that seasonal changes in ozone concentrations are reflected effectively by the concentrations estimated by the multilevel-CNN model structure, with a correlation value of 0.57 ascertained between actual and model results. It is shown that the multilevel-CNN modeling technique is as satisfactory as other modeling techniques in associating the data in a complex medium in air pollution applications.
Goncharenko A. V.
2012-11-01
Full Text Available Influence of subtoxic concentration of manganese chloride in dose equal to LD 50 on condition of plasmatic membranes (model: erythrocytes and functional activity of cell power (model: the isolated liver mitochondrion of rats was studied. It was established that manganese chloride in fixed concentration caused authentic augmentation of sorption capacity of erythrocytes towards alcian blue, influenced increasing of their spontaneous haemolysis and activation of peroxide oxidation of lipids. In experiment on the isolated mitochondrion it was proved that manganese chloride caused dissociation of an oxidizing phosphorusling and complete inhibition of respiration in concentrations of 3 and 4,5mM. These dependences testify that subtoxic concentration of manganese can damage the cell energy. Thus, this pilot research indicated damaging effect of manganese on cellular (erythrocytes and subcellular (mitochondrion levels which are realized through external functioning of membrane structures and deprived them from restoration.
H. Kurtulus OZCAN; Erdem BILGILI; Ulku SAHIN; O. Nuri UCAN; Cuma BAYAT
2007-01-01
Tropospheric ozone concentrations, which are an important air pollutant, are modeled by the use of an artificial intelligence structure. Data obtained from air pollution measurement stations in the city of Istanbul are utilized in constituting the model. A supervised algorithm for the evaluation of ozone concentration using a genetically trained multi-level cellular neural network (ML-CNN) is introduced, developed, and applied to real data. A genetic algorithm is used in the optimization of CNN templates. The model results and the actual measurement results are compared and statistically evaluated. It is observed that seasonal changes in ozone concentrations are reflected effectively by the concentrations estimated by the multilevel-CNN model structure, with a correlation value of 0.57 ascertained between actual and model results. It is shown that the multilevel-CNN modeling technique is as satisfactory as other modeling techniques in associating the data in a complex medium in air pollution applications.
In situ sensing and modeling of molecular events at the cellular level
Yang, Ruiguo
We developed the Atomic Force Microscopy (AFM) based nanorobot in combination with other nanomechanical sensors for the investigation of cell signaling pathways. The AFM nanorobotics hinge on the superior spatial resolution of AFM in imaging and extends it into the measurement of biological processes and manipulation of biological matters. A multiple input single output control system was designed and implemented to solve the issues of nanomanipulation of biological materials, feedback, response frequency and nonlinearity. The AFM nanorobotic system therefore provide the human-directed position, velocity and force control with high frequency feedback, and more importantly it can feed the operator with the real-time imaging of manipulation result from the fast-imaging based local scanning. The use of the system has taken the study of cellular process at the molecular scale into a new level. The cellular response to the physiological conditions can be significantly manifested in cellular mechanics. Dynamic mechanical property has been regarded as biomarkers, sometimes even regulators of the signaling and physiological processes, thus the name mechanobiology. We sought to characterize the relationship between the structural dynamics and the molecular dynamics and the role of them in the regulation of cell behavior. We used the AFM nanorobotics to investigate the mechanical properties in real-time of cells that are stimulated by different chemical species. These reagents could result in similar ion channel responses but distinctive mechanical behaviors. We applied these measurement results to establish a model that describes the cellular stimulation and the mechanical property change, a "two-hit" model that comprises the loss of cell adhesion and the initiation of cell apoptosis. The first hit was verified by functional experiments: depletion of Calcium and nanosurgery to disrupt the cellular adhesion. The second hit was tested by a labeling of apoptotic markers that
Dual transcriptional-translational cascade permits cellular level tuneable expression control.
Morra, Rosa; Shankar, Jayendra; Robinson, Christopher J; Halliwell, Samantha; Butler, Lisa; Upton, Mathew; Hay, Sam; Micklefield, Jason; Dixon, Neil
2016-02-18
The ability to induce gene expression in a small molecule dependent manner has led to many applications in target discovery, functional elucidation and bio-production. To date these applications have relied on a limited set of protein-based control mechanisms operating at the level of transcription initiation. The discovery, design and reengineering of riboswitches offer an alternative means by which to control gene expression. Here we report the development and characterization of a novel tunable recombinant expression system, termed RiboTite, which operates at both the transcriptional and translational level. Using standard inducible promoters and orthogonal riboswitches, a multi-layered modular genetic control circuit was developed to control the expression of both bacteriophage T7 RNA polymerase and recombinant gene(s) of interest. The system was benchmarked against a number of commonly used E. coli expression systems, and shows tight basal control, precise analogue tunability of gene expression at the cellular level, dose-dependent regulation of protein production rates over extended growth periods and enhanced cell viability. This novel system expands the number of E. coli expression systems for use in recombinant protein production and represents a major performance enhancement over and above the most widely used expression systems. PMID:26405200
Kondoh, Hisato; Takada, Shinji; Takemoto, Tatsuya
2016-06-01
The transcription factor gene Sox2, centrally involved in neural primordial regulation, is activated by many enhancers. During the early stages of embryonic development, Sox2 is regulated by the enhancers N2 and N1 in the anterior neural plate (ANP) and posterior neural plate (PNP), respectively. This differential use of the enhancers reflects distinct regulatory mechanisms underlying the genesis of ANP and PNP. The ANP develops directly from the epiblast, triggered by nodal signal inhibition, and via the combined action of TFs SOX2, OTX2, POU3F1, and ZIC2, which promotes the the ANP development and inhibits other cell lineages. In contrast, the PNP is derived from neuromesodermal bipotential axial stem cells that develop into the neural plate when Sox2 is activated by the N1 enhancer, whereas they develop into the paraxial mesoderm when the N1 enhancer is repressed by the action of TBX6. The axial stem cells are maintained by the activity of WNT3a and T (Brachyury). However, at axial levels more anterior to the 8th somites (cervical levels), the development of both the neural plate and somite proceeds in the absence of WNT3a, T, or TBX6. These observations indicate that distinct molecular and cellular mechanisms determine neural plate genesis based on the axial level, and contradict the classical concept of the term "neural induction," which assumes a pan-neural plate mechanism. PMID:27279156
The symmetry algebras of Euclidean M-theory
We study the Euclidean supersymmetric D = 11 M-algebras. We consider two such D = 11 superalgebras: the first one is N = (1,1) self-conjugate complex-Hermitian, with 32 complex supercharges and 1024 real bosonic charges, the second is N = (1,0) complex-holomorphic, with 32 complex supercharges and 528 bosonic charges, which can be obtained by analytic continuation of known Minkowski M-algebra. Due to the Bott's periodicity, we study at first the generic D = 3 Euclidean supersymmetry case. The role of complex and quaternionic structures for D = 3 and D = 11 Euclidean supersymmetry is elucidated. We show that the additional 1024 - 528 = 496 Euclidean tensorial central charges are related with the quaternionic structure of Euclidean D = 11 supercharges, which in complex notation satisfy SU(2) pseudo-Majorana condition. We consider also the corresponding Osterwalder-Schrader conjugations as implying for N = (1,0) case the reality of Euclidean bosonic charges. Finally, we outline some consequences of our results, in particular for D = 11 Euclidean supergravity. (author)
Qi, Yijun; Zhong, Xuehua; Itaya, Asuka; Ding, Biao
2004-01-01
Short interfering RNA (siRNA)-mediated RNA silencing plays an important role in cellular defence against viral infection and abnormal gene expression in multiple organisms. Many viruses have evolved silencing suppressors for counter-defence. We have developed an RNA silencing system in the protoplasts of Nicotiana benthamiana to investigate the functions of viral suppressors at the cellular level. We showed that RNA silencing against a green fluorescent protein (GFP) reporter gene in the prot...
Characterization of cellular traction forces at the single-molecule level
Dunn, Alexander
2013-03-01
The ability of cells to generate and respond to mechanical cues is an essential aspect of stem cell differentiation, embryonic development, and our senses of touch and hearing. However, our understanding of the roles of mechanical force in cell biology remains in its infancy, due largely to a lack of tools that measure the forces generated by living cells at the molecular scale. Here we describe a new technique termed Molecular Force Microscopy (MFM) that visualizes the forces exerted by single cellular adhesion molecules with nm, pN, and sub-second resolutions. MFM uses novel FRET-based molecular tension sensors that bind to a glass coverslip and present a binding site for integrins, a ubiquitous class of cell adhesion proteins. Cell-generated forces stretch the MFM sensor molecules, resulting in decreased FRET with increasing load that can be imaged at the single-molecule level. Human foreskin fibroblasts adhere to surfaces functionalized with the MFM probes and develop robust focal adhesions. FRET values measured using MFM indicate forces of between 1 and 4 pN per integrin, thus providing the first direct measurement of the tension per integrin molecule necessary to form stable adhesions. The relatively narrow force distribution suggests that mechanical tension is subject to exquisite feedback and control at the molecular level.
Liu, Su; Jiang, Wei; Wu, Bing; Yu, Jing; Yu, Haiyan; Zhang, Xu-Xiang; Torres-Duarte, Cristina; Cherr, Gary N
2016-06-01
Low levels of graphene and graphene oxide (GO) are considered to be environmentally safe. In this study, we analyzed the potential effects of graphene and GO at relatively low concentrations on cellular xenobiotic defense system mediated by efflux transporters. The results showed that graphene (<0.5 μg/mL) and GO (<20 μg/mL) did not decrease cell viability, generate reactive oxygen species, or disrupt mitochondrial function. However, graphene and GO at the nontoxic concentrations could increase calcein-AM (CAM, an indicator of membrane ATP-binding cassette (ABC) transporter) activity) accumulation, indicating inhibition of ABC transporters' efflux capabilities. This inhibition was observed even at 0.005 μg/mL graphene and 0.05 μg/mL GO, which are 100 times and 400 times lower than their lowest toxic concentration from cytotoxicity experiments, respectively. The inhibition of ABC transporters significantly increased the toxicity of paraquat and arsenic, known substrates of ABC transporters. The inhibition of ABC transporters was found to be based on graphene and GO damaging the plasma membrane structure and fluidity, thus altering functions of transmembrane ABC transporters. This study demonstrates that low levels of graphene and GO are not environmentally safe since they can significantly make cell more susceptible to other xenobiotics, and this chemosensitizing activity should be considered in the risk assessment of graphene and GO. PMID:26554512
Irundika H K Dias
Full Text Available The production of high levels of reactive oxygen species by neutrophils is associated with the local and systemic destructive phenotype found in the chronic inflammatory disease periodontitis. In the present study, we investigated the ability of sulforaphane (SFN to restore cellular glutathione levels and reduce the hyperactivity of circulating neutrophils associated with chronic periodontitis. Using differentiated HL60 cells as a neutrophil model, here we show that generation of extracellular O2 (. - by the nicotinamide adenine dinucleotide (NADPH oxidase complex is increased by intracellular glutathione depletion. This may be attributed to the upregulation of thiol regulated acid sphingomyelinase driven lipid raft formation. Intracellular glutathione was also lower in primary neutrophils from periodontitis patients and, consistent with our previous findings, patients neutrophils were hyper-reactive to stimuli. The activity of nuclear factor erythroid-2-related factor 2 (Nrf2, a master regulator of the antioxidant response, is impaired in circulating neutrophils from chronic periodontitis patients. Although patients' neutrophils exhibit a low reduced glutathione (GSH/oxidised glutathione (GSSG ratio and a higher total Nrf2 level, the DNA-binding activity of nuclear Nrf2 remained unchanged relative to healthy controls and had reduced expression of glutamate cysteine ligase catalytic (GCLC, and modifier (GCLM subunit mRNAs, compared to periodontally healthy subjects neutrophils. Pre-treatment with SFN increased expression of GCLC and GCM, improved intracellular GSH/GSSG ratios and reduced agonist-activated extracellular O2 (. - production in both dHL60 and primary neutrophils from patients with periodontitis and controls. These findings suggest that a deficiency in Nrf2-dependent pathways may underpin susceptibility to hyper-reactivity in circulating primary neutrophils during chronic periodontitis.
Khalid, Muhammad Zeeshan
2016-01-01
After the discovery of laser therapy it was realized it has useful application of wound healing and reduce pain, but due to the poor understanding of the mechanism and dose response this technique remained to be controversial for therapeutic applications. In order to understand the working and effectiveness different experiments were performed to determine the laser beam effect at the cellular and tissue level. This article discusses the mechanism of beam interaction at tissues and cellular l...
Generators of the sister of Euclidean Picard modular group
Xie, Baohua
2015-01-01
The sister of Eisenstein-Picard modular group was described in [8]. In this paper we give a similar definition of the sister of the Euclidean-Picard modular group and find its generators by using a geometric method.
Quaternionic Similar Curves in 4-dimensional Euclidean Space
Önder, Mehmet
2012-01-01
In this paper, we introduce the quaternionic similar curves in 4-dimensional Euclidean space. We show that the families of quaternionic curves with vanishing curvatures form the families of quaternionic similar curves.
A High-Precision Micropipette Sensor for Cellular-Level Real-Time Thermal Characterization
Wonseok Chang
2011-09-01
Full Text Available We report herein development of a novel glass micropipette thermal sensor fabricated in a cost-effective manner, which is capable of measuring steady thermal fluctuation at spatial resolution of ~2 µm with an accuracy of ±0.01 °C. We produced and tested various micrometer-sized sensors, ranging from 2 µm to 30 µm. The sensor comprises unleaded low-melting-point solder alloy (Sn-based as a core metal inside a pulled borosilicate glass pipette and a thin film of nickel coating outside, creating a thermocouple junction at the tip. The sensor was calibrated using a thermally insulated calibration chamber, the temperature of which can be controlled with an accuracy of ±0.01 °C, and the thermoelectric power (Seebeck coefficient of the sensor was recorded from 8.46 to 8.86 µV/°C. We have demonstrated the capability of measuring temperatures at a cellular level by inserting our temperature sensor into the membrane of a live retinal pigment epithelium cell subjected to a laser beam with a focal spot of 6 μm. We measured transient temperature profiles and the maximum temperatures were in the range of 38–55 ± 0.5 °C.
Jin, Taewon; Kim, Min Jeong; Heo, Won Il; Park, Kui Young; Choi, Sun Young; Lee, Mi-Kyung; Hong, Seung-Phil; Kim, Seong-Jin; Im, Myung; Moon, Nam Ju; Seo, Seong Jun
2016-09-01
Stress-induced premature senescence or aging causes dysfunction in the human somatic system. Adiponectin (Acrp30) plays a role in functional recovery, especially with adenosine 3',5'-monophosphate (AMP)-activated protein kinase (AMPK) and silent mating type information regulation 2 homolog 1 (SIRT1). Acrp30 stimulation reduced the premature senescence positive ratio induced by hydrogen peroxide (H2O2) and restituted human β-defensin 2 (hBD-2) levels in senescent keratinocytes. Acrp30 recovered AMPK activity in senescent keratinocytes and increased SIRT1 deacetylation activity. As a result, FoxO1 and FoxO3 transcription activity was recovered. Additionally, Acrp30 stimulation suppresses NFκB p65, which induces abnormal expression of hBD-2 induced by H2O2. In the present study, we have shown that Acrp30 reduces premature senescence and recovers cellular function in keratinocytes. These results suggest a role for Acrp30 as an anti-aging agent to improve impaired skin immune barriers. PMID:27349869
A high-precision micropipette sensor for cellular-level real-time thermal characterization.
Shrestha, Ramesh; Choi, Tae-Youl; Chang, Wonseok; Kim, Donsik
2011-01-01
We report herein development of a novel glass micropipette thermal sensor fabricated in a cost-effective manner, which is capable of measuring steady thermal fluctuation at spatial resolution of ∼2 μm with an accuracy of ±0.01 °C. We produced and tested various micrometer-sized sensors, ranging from 2 μm to 30 μm. The sensor comprises unleaded low-melting-point solder alloy (Sn-based) as a core metal inside a pulled borosilicate glass pipette and a thin film of nickel coating outside, creating a thermocouple junction at the tip. The sensor was calibrated using a thermally insulated calibration chamber, the temperature of which can be controlled with an accuracy of ±0.01 °C, and the thermoelectric power (Seebeck coefficient) of the sensor was recorded from 8.46 to 8.86 μV/°C. We have demonstrated the capability of measuring temperatures at a cellular level by inserting our temperature sensor into the membrane of a live retinal pigment epithelium cell subjected to a laser beam with a focal spot of 6 μm. We measured transient temperature profiles and the maximum temperatures were in the range of 38-55 ± 0.5 °C. PMID:22164108
Volinsky, Roman; Kinnunen, Paavo K J
2013-06-01
The oxidation of lipids has been shown to impact virtually all cellular processes. The paradigm has been that this involvement is due to interference with the functions of membrane-associated proteins. It is only recently that methodological advances in molecular-level detection and identification have begun to provide insights into oxidative lipid modification and its involvement in cell signaling as well as in major diseases and inflammation. Extensive evidence suggests a correlation between lipid peroxidation and degenerative neurological diseases such as Parkinson's and Alzheimer's, as well as type 2 diabetes and cancer. Despite the obvious relevance of understanding the molecular basis of the above ailments, the exact modes of action of oxidized lipids have remained elusive. In this minireview, we summarize recent findings on the biophysical characteristics of biomembranes following oxidative derivatization of their lipids, and how these altered properties are involved in both physiological processes and major pathological conditions. Lipid-bearing, oxidatively truncated and functionalized acyl chains are known to modify membrane bulk physical properties, such as thermal phase behavior, bilayer thickness, hydration and polarity profiles, as manifest in the altered structural dynamics of lipid bilayers, leading to augmented membrane permeability, fast lipid transbilayer diffusion (flip-flop), loss of lipid asymmetry (scrambling) and phase segregation (the formation of 'rafts'). These changes, together with the generated reactive lipid derivatives, can be further expected to interfere with lipid-protein interactions, influencing metabolic pathways, causing inflammation, the execution phase in apoptosis and initiating pathological processes. PMID:23506295
Tracking and quantifying polymer therapeutic distribution on a cellular level using 3D dSTORM.
Hartley, Jonathan M; Zhang, Rui; Gudheti, Manasa; Yang, Jiyuan; Kopeček, Jindřich
2016-06-10
We used a single-molecule localization technique called direct stochastic optical reconstruction microscopy (dSTORM) to quantify both colocalization and spatial distribution on a cellular level for two conceptually different N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer conjugates. Microscopy images were acquired of entire cells with resolutions as high as 25nm revealing the nanoscale distribution of the fluorescently labeled therapeutic components. Drug-free macromolecular therapeutics consisting of two self-assembling nanoconjugates showed slight increase in nanoclusters on the cell surface with time. Additionally, dSTORM provided high resolution images of the nanoscale organization of the self-assembling conjugates at the interface between two cells. A conjugate designed for treating ovarian cancer showed that the model drug (Cy3) and polymer bound to Cy5 were colocalized at an early time point before the model drug was enzymatically cleaved from the polymer. Using spatial descriptive statistics it was found that the drug was randomly distributed after 24h while the polymer bound dye remained in clusters. Four different fluorescent dyes were used and two different therapeutic systems were tested to demonstrate the versatility and possible general applicability of dSTORM for use in studying drug delivery systems. PMID:26855050
Khalid, Muhammad Zeeshan
2016-01-01
After the discovery of laser therapy it was realized it has useful application of wound healing and reduce pain, but due to the poor understanding of the mechanism and dose response this technique remained to be controversial for therapeutic applications. In order to understand the working and effectiveness different experiments were performed to determine the laser beam effect at the cellular and tissue level. This article discusses the mechanism of beam interaction at tissues and cellular level with different light sources and dosimetry principles for clinical application of low level laser therapy. Different application techniques and methods currently in use for clinical treatment has also been reviewed.
Euclidean Reconstruction and Affine Camera Calibration Using Controlled Robot Motions
Horaud, Radu; Christy, Stéphane; Mohr, Roger
1997-01-01
We are addressing the problem of Euclidean reconstruction with an uncalibrated affine camera and the calibration of this camera. We investigate constraints under which the Euclidean shape and motion problem becomes linear. The theoretical study described in this paper leads us to impose some practical constraints that the camera is mounted onto a robot arm and that the robot is executing controlled motions whose parameters are known. The affine camera model considered here is just an approxim...
On Clustering Time Series Using Euclidean Distance and Pearson Correlation
MICHAEL R BERTHOLD; Höppner, Frank
2016-01-01
For time series comparisons, it has often been observed that z-score normalized Euclidean distances far outperform the unnormalized variant. In this paper we show that a z-score normalized, squared Euclidean Distance is, in fact, equal to a distance based on Pearson Correlation. This has profound impact on many distance-based classification or clustering methods. In addition to this theoretically sound result we also show that the often used k-Means algorithm formally needs a mod ification to...
Embedding spacetime via a geodesically equivalent metric of Euclidean signature
Jonsson, Rickard
2007-01-01
Starting from the equations of motion in a 1 + 1 static, diagonal, Lorentzian spacetime, such as the Schwarzschild radial line element, I find another metric, but with Euclidean signature, which produces the same geodesics x(t). This geodesically equivalent, or dual, metric can be embedded in ordinary Euclidean space. On the embedded surface freely falling particles move on the shortest path. Thus one can visualize how acceleration in a gravitational field is explained by particles moving fre...
The relation between Euclidean and Lorentzian 2D quantum gravity
Ambjørn, J.; Correia, J; Kristjansen, C.; Loll, R.
2006-01-01
Starting from 2D Euclidean quantum gravity, we show that one recovers 2D Lorentzian quantum gravity by removing all baby universes. Using a peeling procedure to decompose the discrete, triangulated geometries along a one-dimensional path, we explicitly associate with each Euclidean space-time a (generalized) Lorentzian spacetime. This motivates a map between the parameter spaces of the two theories, under which their propagators get identified. In two dimensions, Lorentzian quantum gravity ca...
Euclidean supersymmetrization of instantons and self-dual monopoles
We show that N=1 D=4 Euclidean supersymmetry leads to the complexification of gauge potentials, and that to have a supersymmetric Euclidean D=4 theory which allows for the selfduality of real gauge potentials, the supersymmetry has to be extended to even N, i.e. at least N=2. We also discuss the supersymmetrization of Manton's procedure of using the dimensional reduction D=4 → D=3 to derive self-dual monopoles from instantons. (author)
CBFA1 and topoisomerase I mRNA levels decline during cellular aging of human trabecular osteoblasts
Christiansen, M; Kveiborg, Marie; Kassem, M;
2000-01-01
In order to understand the reasons for age-related impairment of the function of bone forming osteoblasts, we have examined the steady-state mRNA levels of the transcription factor CBFA1 and topoisomerase I during cellular aging of normal human trabecular osteoblasts, by the use of semiquantitative...... reverse transcriptase-polymerase chain reaction (RT-PCR). There is a progressive and significant reduction of the CBFA1 steady-state mRNA level down to 50% during cellular aging of human osteoblasts. In comparison to the normal cells, human osteosarcoma cell lines SaOS-2 and KHOS/NP, and the SV40...
Combined phase and X-Ray fluorescence imaging at the sub-cellular level
This work presents some recent developments in the field of hard X-ray imaging applied to biomedical research. As the discipline is evolving quickly, new questions appear and the list of needs becomes bigger. Some of them are dealt with in this manuscript. It has been shown that the ID22NI beamline of the ESRF can serve as a proper experimental setup to investigate diverse aspects of cellular research. Together with its high spatial resolution, high flux and high energy range the experimental setup provides bigger field of view, is less sensitive to radiation damages (while taking phase contrast images) and suits well chemical analysis with emphasis on endogenous metals (Zn, Fe, Mn) but also with a possibility for exogenous one's like these found in nanoparticles (Au, Pt, Ag) study. Two synchrotron-based imaging techniques, fluorescence and phase contrast imaging were used in this research project. They were correlated with each other on a number of biological cases, from bacteria E.coli to various cells (HEK 293, PC12, MRC5VA, red blood cells). The explorations made in the chapter 5 allowed preparation of more established and detailed analysis, described in the next chapter where both techniques, X-ray fluorescence and phase contrast imaging, were exploited in order to access absolute metal projected mass fraction in a whole cell. The final image presents for the first time true quantitative information at the sub-cellular level, not biased by the cell thickness. Thus for the first time a fluorescence map serves as a complete quantitative image of a cell without any risk of misinterpretation. Once both maps are divided by each other pixel by pixel (fluorescence map divided by the phase map) they present a complete and final result of the metal (Zn in this work) projected mass fraction in ppm of dry weight. For the purpose of this calculation the analysis was extended to calibration (non-biological) samples. Polystyrene spheres of a known diameter and known
Euclidean Geometric Objects in the Clifford Geometric Algebra of {Origin, 3-Space, Infinity}
Hitzer, Eckhard
2013-01-01
This paper concentrates on the homogeneous (conformal) model of Euclidean space (Horosphere) with subspaces that intuitively correspond to Euclidean geometric objects in three dimensions. Mathematical details of the construction and (useful) parametrizations of the 3D Euclidean object models are explicitly demonstrated in order to show how 3D Euclidean information on positions, orientations and radii can be extracted.
Agostoni, Marco; Waters, Christopher M; Montgomery, Beronda L
2016-02-01
The second messenger cyclic dimeric (3'→5') GMP (cyclic di-GMP or c-di-GMP) has been implicated in the transition between motile and sessile lifestyles in bacteria. In this study, we demonstrate that biofilm formation, cellular aggregation or flocculation, and cellular buoyancy are under the control of c-di-GMP in Synechocystis sp. PCC 6803 (Synechocystis) and Fremyella diplosiphon. Synechocystis is a unicellular cyanobacterium and displays lower levels of c-di-GMP; F. diplosiphon is filamentous and displays higher intracellular c-di-GMP levels. We transformed Synechocystis and F. diplosiphon with a plasmid for constitutive expression of genes encoding diguanylate cylase (DGC) and phosphodiesterase (PDE) proteins from Vibrio cholerae or Escherichia coli, respectively. These engineered strains allowed us to modulate intracellular c-di-GMP levels. Biofilm formation and cellular deposition were induced in the DGC-expressing Synechocystis strain which exhibited high intracellular levels of c-di-GMP; whereas strains expressing PDE in Synechocystis and F. diplosiphon to drive low intracellular levels of c-di-GMP exhibited enhanced cellular buoyancy. In addition, the PDE-expressing F. diplosiphon strain showed elevated chlorophyll levels. These results imply roles for coordinating c-di-GMP homeostasis in regulating native cyanobacterial phenotypes. Engineering exogenous DGC or PDE proteins to regulate intracellular c-di-GMP levels represents an effective tool for uncovering cryptic phenotypes or modulating phenotypes in cyanobacteria for practical applications in biotechnology applicable in photobioreactors and in green biotechnologies, such as energy-efficient harvesting of cellular biomass or the treatment of metal-containing wastewaters. PMID:26192200
SINGLE-CELL LEVEL INVESTIGATION OF CYTOSKELETAL/CELLULAR RESPONSE TO EXTERNAL STIMULI
Hiddessen, A L
2007-02-26
A detailed understanding of the molecular mechanisms by which chemical signals control cell behavior is needed if the complex biological processes of embryogenesis, development, health and disease are to be completely understood. Yet, if we are to fully understand the molecular mechanisms controlling cell behavior, measurements at the single cell level are needed to supplement information gained from population level studies. One of the major challenges to accomplishing studies at the single cell level has been a lack of physical tools to complement the powerful molecular biological assays which have provided much of what we currently know about cell behavior. The goal of this exploratory project is the development of an experimental platform that facilitates integrated observation, tracking and analysis of the responses of many individual cells to controlled environmental factors (e.g. extracellular signals). Toward this goal, we developed chemically-patterned microarrays of both adherent and suspension mammalian cell types. A novel chemical patterning methodology, based on photocatalytic lithography, was developed to construct biomolecule and cell arrays that facilitate analysis of biological function. Our patterning techniques rely on inexpensive stamp materials and visible light, and do not necessitate mass transport or specified substrates. Patterned silicon and glass substrates are modified such that there is a non-biofouling polymer matrix surrounding the adhesive regions that target biomolecules and cells. Fluorescence and reflectance microscopy reveal successful patterning of proteins and single to small clusters of mammalian cells. In vitro assays conducted upon cells on the patterned arrays demonstrate the viability of cells interfacing with this synthetic system. Hence, we have successfully established a versatile cell measurement platform which can be used to characterize the molecular regulators of cellular behavior in a variety of important
Alon Kalo
2015-04-01
Full Text Available The transcriptional response of β-actin to extra-cellular stimuli is a paradigm for transcription factor complex assembly and regulation. Serum induction leads to a precisely timed pulse of β-actin transcription in the cell population. Actin protein is proposed to be involved in this response, but it is not known whether cellular actin levels affect nuclear β-actin transcription. We perturbed the levels of key signaling factors and examined the effect on the induced transcriptional pulse by following endogenous β-actin alleles in single living cells. Lowering serum response factor (SRF protein levels leads to loss of pulse integrity, whereas reducing actin protein levels reveals positive feedback regulation, resulting in elevated gene activation and a prolonged transcriptional response. Thus, transcriptional pulse fidelity requires regulated amounts of signaling proteins, and perturbations in factor levels eliminate the physiological response, resulting in either tuning down or exaggeration of the transcriptional pulse.
A mathematical model of cortical bone remodeling at cellular level under mechanical stimulus
Qing-Hua Qin; Ya-Nan Wang
2012-01-01
A bone cell population dynamics model for cortical bone remodeling under mechanical stimulus is developed in this paper.The external experiments extracted from the literature which have not been used in the creation of the model are used to test the validity of the model.Not only can the model compare reasonably well with these experimental results such as the increase percentage of final values of bone mineral content (BMC) and bone fracture energy (BFE) among different loading schemes (which proves the validity of the model),but also predict the realtime development pattern of BMC and BFE,as well as the dynamics of osteoblasts (OBA),osteoclasts (OCA),nitric oxide (NO) and prostaglandin E2 (PGE2) for each loading scheme,which can hardly be monitored through experiment.In conclusion,the model is the first of its kind that is able to provide an insight into the quantitative mechanism of bone remodeling at cellular level by which bone cells are activated by mechanical stimulus in order to start resorption/formation of bone mass.More importantly,this model has laid a solid foundation based on which future work such as systemic control theory analysis of bone remodeling under mechanical stimulus can be investigated.The to-be identified control mechanism will help to develop effective drugs and combined nonpharmacological therapies to combat bone loss pathologies.Also this deeper understanding of how mechanical forces quantitatively interact with skeletal tissue is essential for the generation of bone tissue for tissue replacement purposes in tissue engineering.
Brown, Joseph N.; Ortiz, Gabriel M.; Angel, Thomas E.; Jacobs, Jon M.; Gritsenko, Marina A.; Chan, Eric Y.; Purdy, David E.; Murnane, Robert D.; Larsen, Kay; Palermo, Robert E.; Shukla, Anil K.; Clauss, Therese RW; Katze, Michael G.; McCune, Joseph M.; Smith, Richard D.
2012-05-11
Morphine has long been known to have immunosuppressive properties in vivo, but the molecular and immunologic changes induced by it are incompletely understood. As a prelude to understanding how these changes might interact with lentiviral infection in vivo, animals from two non-human primate (NHP) species [African green monkey (AGMs) and pigtailed macaque (PTs)] were provided morphine and studied using a systems biology approach. Biological specimens were obtained from multiple sources (e.g., lymph node, colon, cerebrospinal fluid (CSF), and peripheral blood) before and after the administration of morphine (titrated up to a maximum dose of 5 mg/kg over a period of 20 days). Cellular immune, plasma cytokine, and proteome changes were measured and morphine-induced changes in these parameters were assessed on an inter-organ, inter-individual, and inter-species basis. In both species, morphine was associated with decreased levels of (Ki-67+) T cell activation but with only minimal changes in overall T cell counts, neutrophil counts, and NK cells counts. While changes in T cell maturation were observed, these varied across the various tissue/fluid compartments studied. Proteomic analysis revealed a morphine-induced suppressive effect in the lymph node, with decreased abundance of protein mediators involved in the functional categories of energy metabolism, signaling, and maintenance of cell structure. These findings have relevance for understanding the impact of heroin addiction and the opioids used to treat addiction as well as on the interplay between opioid abuse and the response to infection with agents such as the human immunodeficiency virus, type 1 (HIV).
The Riemann and Lorentz constant curvature surfaces are investigated from an Euclidean point of view. The four surfaces (constant positive and constant negative curvatures with definite and non-definite fine elements) are represented as surfaces in a Riemannian or in a particular semi-Riemannian flat space and it is shown that the complex and the hyperbolic numbers allow to obtain the same equations for the corresponding Riemann and Lorentz surfaces, respectively. Moreover it is shown that the geodesics on the Lorentz surfaces states, from a physical point of view, a link between curvature and fields. This result is obtained just as a consequence of the space-time geometrical symmetry, without invoking the famous Einstein general relativity postulate
ZHANG Hong-xin; LU Ying-hua; ZHANG Jin-ling
2007-01-01
Hierarchical clustering algorithms, such as Pearson's correlation, Euclidean distance, Euclidean distance harmonic,Spearman rank correlation, Kendall's tau, and City-block distance, were used to find the best way to establish theoretical MAPK/Erk signaling pathway on the basis of breast cancer line MCF-7 gene expressions. The algorithm consttucts a hierarchy from top to bottom on the basis of a self-organizing tree. It dynamically finds the number of clusters at each level. It was found that only Euclidean distance harmonic is fit for the analysis of the cascade composed from a RAF1 (c-Raf), a MKNK1, a MAPKK (MEK1/2) to MAPK (Erk) in breast cancer line MCF-7. The result is consistent with the biological experimental MAP/Erk signaling pathway, and the theoretical MAPK/Erk signaling pathway on breast cancer line MCF-7 is set up.
The non-Euclidean revolution with an introduction by H.S.M. Coxeter
Trudeau, Richard J
2001-01-01
How unique and definitive is Euclidean geometry in describing the "real" space in which we live? Richard Trudeau confronts the fundamental question of truth and its representation through mathematical models in The Non-Euclidean Revolution. First, the author analyzes geometry in its historical and philosophical setting; second, he examines a revolution every bit as significant as the Copernican revolution in astronomy and the Darwinian revolution in biology; third, on the most speculative level, he questions the possibility of absolute knowledge of the world. Trudeau writes in a lively, entertaining, and highly accessible style. His book provides one of the most stimulating and personal presentations of a struggle with the nature of truth in mathematics and the physical world. A portion of the book won the Pólya Prize, a distinguished award from the Mathematical Association of America.
Flexible intuitions of Euclidean geometry in an Amazonian indigene group.
Izard, Véronique; Pica, Pierre; Spelke, Elizabeth S; Dehaene, Stanislas
2011-06-14
Kant argued that Euclidean geometry is synthesized on the basis of an a priori intuition of space. This proposal inspired much behavioral research probing whether spatial navigation in humans and animals conforms to the predictions of Euclidean geometry. However, Euclidean geometry also includes concepts that transcend the perceptible, such as objects that are infinitely small or infinitely large, or statements of necessity and impossibility. We tested the hypothesis that certain aspects of nonperceptible Euclidian geometry map onto intuitions of space that are present in all humans, even in the absence of formal mathematical education. Our tests probed intuitions of points, lines, and surfaces in participants from an indigene group in the Amazon, the Mundurucu, as well as adults and age-matched children controls from the United States and France and younger US children without education in geometry. The responses of Mundurucu adults and children converged with that of mathematically educated adults and children and revealed an intuitive understanding of essential properties of Euclidean geometry. For instance, on a surface described to them as perfectly planar, the Mundurucu's estimations of the internal angles of triangles added up to ~180 degrees, and when asked explicitly, they stated that there exists one single parallel line to any given line through a given point. These intuitions were also partially in place in the group of younger US participants. We conclude that, during childhood, humans develop geometrical intuitions that spontaneously accord with the principles of Euclidean geometry, even in the absence of training in mathematics. PMID:21606377
Transmural heterogeneity of cellular level power output is reduced in human heart failure
Haynes, Premi; Nava, Kristofer E.; Lawson, Benjamin A.; Chung, Charles S.; Mitov, Mihail I.; Campbell, Stuart G.; Stromberg, Arnold J.; Sadayappan, Sakthivel; Bonnell, Mark R.; Hoopes, Charles W.; Campbell, Kenneth S.
2014-01-01
Heart failure is associated with pump dysfunction and remodeling but it is not yet known if the condition affects different transmural regions of the heart in the same way. We tested the hypotheses that the left ventricles of non-failing human hearts exhibit transmural heterogeneity of cellular level contractile properties, and that heart failure produces transmural region-specific changes in contractile function. Permeabilized samples were prepared from the sub-epicardial, mid-myocardial, and sub-endocardial regions of the left ventricular free wall of non-failing (n=6) and failing (n=10) human hearts. Power, an in vitro index of systolic function, was higher in non-failing mid-myocardial samples (0.59±0.06 μW mg−1) than in samples from the sub-epicardium (p=0.021) and the sub-endocardium (p=0.015). Non-failing mid-myocardial samples also produced more isometric force (14.3±1.33 kN m−2) than samples from the sub-epicardium (p=0.008) and the sub-endocardium (p=0.026). Heart failure reduced power (p=0.009) and force (p=0.042) but affected the mid-myocardium more than the other transmural regions. Fibrosis increased with heart failure (p=0.021) and mid-myocardial tissue from failing hearts contained more collagen than matched sub-epicardial (p<0.001) and sub-endocardial (p=0.043) samples. Power output was correlated with the relative content of actin and troponin I, and was also statistically linked to the relative content and phosphorylation of desmin and myosin light chain- 1. Non-failing human hearts exhibit transmural heterogeneity of contractile properties. In failing organs, region-specific fibrosis produces the greatest contractile deficits in the mid-myocardium. Targeting fibrosis and sarcomeric proteins in the mid-myocardium may be particularly effective therapies for heart failure. PMID:24560668
Valsecchi, Federica; Koopman, Werner J. H.; Manjeri, Ganesh R.; Rodenburg, Richard J.; Smeitink, Jan A. M.; Willems, Peter H. G. M.
2010-01-01
Mitochondrial oxidative phosphorylation (OXPHOS) represents the final step in the conversion of nutrients into cellular energy. Genetic defects in the OXPHOS system have an incidence between 1:5,000 and 1:10,000 live births. Inherited isolated deficiency of the first complex (CI) of this system, a multisubunit assembly of 45 different proteins,…
A study of the biological effects of rare earth elements at cellular level using nuclear techniques
Objective: To investigate the biological effects and the effecting mechanisms of rare earth elements La, Gd and Ce on cultured rat cells. Methods: The biological effects of La3+ on cultured rat cells and the subcellular distribution of La and Gd and Ce, and the inflow of 45Ca2+ into the cells and total cellular calcium were measured by isotopic tracing, Proton Induced X Ray Emission Analysis (PIXE) and the techniques of biochemistry and cellular biology. Results: La3+ at the concentration of 10-10(or 10-9) - 10-6 mol/L significantly increased quantity of incorporation of 3H-TdR into DNA, total cellular protein and the activity of succinic dehydrogenase of mitochondria. The cell cycle analysis showed that the proportions of cells in S phase were accordingly increased acted by La3+ at above range of concentration. But these values were significantly decreased when concentration of La3+ raised to 10-4 - 10-3 mol/L. It was further discovered that La, Gd and Ce distributed mostly in the nuclei, and then in membranes. Gd and Ce also promoted the inflow of 45Ca2+ into the cells and increased the total calcium content in cells. Conclusions: 1) La3+ at a wide concentration range of 10-10( or 10-9) - 10-6 mol/L promotes proliferation of cultured rat cells, but at even higher concentration (10-4 - 10-3 mol/L) shows cellular toxicity, and there is a striking dose-effect relationship. 2) La, Gd and Ce can enter the cells and mainly distribute in the nuclei. 3) Gd and Ce can promote the inflow of extracellular Ca2+ into the cells and increase total cellular calcium
Quaternion analyticity and conformally Kaehlerian structure in Euclidean gravity
Guersey, F.; Chia-Hsiung Tze (Yale Univ., New Haven, CT (USA). Gibbs Lab.)
1984-09-01
Starting from the fact that the d = 4 Euclidean flat spacetime is conformally related to the Kaehler manifold H/sup 2/xS/sup 2/, we show the Euclidean Schwarzschild metric to be conformally related to another Kaehler manifold M/sup 2/xS/sup 2/ with M/sup 2/ being conformal to H/sup 2/ in two dimensions. Both metrics which are conformally Kaehlerian, are form-invariant under the infinite parameter Fueter group, the Euclidean counterpart of Milne's group of clock regraduation. The associated Einstein's equations translate into Fueter's quaternionic analyticity. The latter leads to an infinite number of local continuity equations.
Charged particle-induced modification of cellular genomic DNA and gene expression level
Aim of this study is to understand cellular and molecular nature of cancer cells survived for long term after charged particle therapy. During the period of 1st year, clonogenic sensitivity of various cancer cell lines against charged particles was investigated by two experimental strategies. Firstly, human glioblastoma cell line, Becker, was investigated for the phenotypic changes after long term survival period (3 weeks). Especially, the cells were revealed to be sensitized toward secondary exposure of charged particles in a way of primary dose-dependence. However, this tendency was clearly eliminated when cells were treated by 5-azacytidine, a DNA methylation inhibitor, before the primary exposure. Thus, epigenetic regulations of cellular genomic DNA were supposed to play important roles in the radiation sensitivity changes of the long-term survived cells. In the second approach, mouse cancer cell line analysis in the presence of 5-azacytidine revealed epigenetic heterogeneity of charged particle sensitivity within the cell population. (author)
Inside s-inner product sets and Euclidean designs
Nozaki, Hiroshi
2009-01-01
A finite set X in the Euclidean space is called an s-inner product set if the set of the usual inner products of any two distinct points in X has size s. First, we give a special upper bound for the cardinality of an s-inner product set on concentric spheres. The upper bound coincides with the known lower bound for the size of a Euclidean 2s-design. Secondly, we prove the non-existence of 2- or 3-inner product sets on two concentric spheres attaining the upper bound for any d>1. The efficient...
Classification of flat slant surfaces in complex Euclidean plane
Chen, Bang-yen
2002-01-01
It is well-known that the classification of flat surfaces in Euclidean 3space is one of the most basic results in differential geometry. For surfaces in the complex Euclidean plane $C^{2}$ endowed with almost complex structure $J$ , flat surfaces are the simplest ones from intrinsic point of views. On the other hand, from $J$ -action point of views, the most natural surfaces in $C^{2}$ are slant surfaces, i.e., surfaces with constant Wintinger angle. In this paper the author completely classi...
Maria Filippova; Valery Filippov; Williams, Vonetta M; Kangling Zhang; Anatolii Kokoza; Svetlana Bashkirova; Penelope Duerksen-Hughes
2014-01-01
Treatment of advanced and relapsed cervical cancer is frequently ineffective, due in large part to chemoresistance. To examine the pathways responsible, we employed the cervical carcinoma-derived SiHa and CaSki cells as cellular models of resistance and sensitivity, respectively, to treatment with chemotherapeutic agents, doxorubicin, and cisplatin. We compared the proteomic profiles of SiHa and CaSki cells and identified pathways with the potential to contribute to the differential response....
Riggio Cristina
2009-01-01
Full Text Available Abstract In this article, a carbon nanotube (CNT array-based system combined with a polymer thin film is proposed as an effective drug release device directly at cellular level. The polymeric film embedded in the CNT array is described and characterized in terms of release kinetics, while in vitro assays on PC12 cell line have been performed in order to assess the efficiency and functionality of the entrapped agent (neural growth factor, NGF. PC12 cell differentiation, following incubation on the CNT array embedding the alginate delivery film, demonstrated the effectiveness of the proposed solution. The achieved results indicate that polymeric technology could be efficiently embedded in CNT array acting as drug delivery system at cellular level. The implication of this study opens several perspectives in particular in the field of neurointerfaces, combining several functions into a single platform.
Luís André Mendes; Maria, Vera L.; Scott-Fordsmand, Janeck J.; Amorim, Mónica J. B.
2015-01-01
The effects of nanomaterials have been primarily assessed based on standard ecotoxicity guidelines. However, by adapting alternative measures the information gained could be enhanced considerably, e.g., studies should focus on more mechanistic approaches. Here, the environmental risk posed by the presence of silver nanoparticles (Ag NM300K) in soil was investigated, anchoring population and cellular level effects, i.e., survival, reproduction (28 days) and oxidative stress markers (0, 2, 4, 6...
Gong, Hui; Xu, Dongli; Yuan, Jing; Li, Xiangning; Guo, Congdi; Peng, Jie; Li, Yuxin; Schwarz, Lindsay A.; Li, Anan; Hu, Bihe; Xiong, Benyi; Sun, Qingtao; Zhang, Yalun; Liu, Jiepeng; Zhong, Qiuyuan
2016-01-01
The precise annotation and accurate identification of neural structures are prerequisites for studying mammalian brain function. The orientation of neurons and neural circuits is usually determined by mapping brain images to coarse axial-sampling planar reference atlases. However, individual differences at the cellular level likely lead to position errors and an inability to orient neural projections at single-cell resolution. Here, we present a high-throughput precision imaging method that c...
Chronic arsenic exposure increases risk for the development of diabetes, vascular disease, and cancers of the skin, lung, kidney, and bladder. This study investigates the effects of arsenite [As(III)] on human urothelial cells (UROtsa). As(III) toxicity was determined by exposing confluent UROtsa cells to As(III) (0.5-200 μM). Depleting cellular glutathione levels with buthionine sulfoximine (BSO) potentiated the toxicity of As(III). Cell viability was assessed with the (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. UROtsa cell ability to biotransform As(III) was determined by dosing cells with environmentally relevant concentrations of As(III) followed by HPLC/ICP-MS analysis of cell media and lysate. Both pentavalent and trivalent monomethylated products were detected. Although cytotoxicity was observed at high doses of As(III) (approximately 100 μM) in UROtsa cells, perturbations of a variety of molecular processes occurred at much lower doses. Exposure to low-level As(III) (0.5-25 μM) causes an accumulation of ubiquitin (Ub)-conjugated proteins. This effect is enhanced when cellular glutathione levels have been reduced with BSO treatment. Because As(III) has many effects on UROtsa cells, a greater understanding of how As(III) is affecting cellular proteins in a target tissue will lead to a better understanding of the mechanism of toxicity and pathogenesis for low-level As(III)
Might carnitine status in animals indicate environmental/toxicological harm at the cellular level?
Garst, J.E.
1995-12-01
It is well known that R-(L)-carnitine (Cn) is essential for the energy-producing, mitochondrial beta-oxidation of long chain fatty acids. Cn can ameliorate the diverse effects of drugs, a chemicals and pollutants. Moreover, the toxicities of carbon monoxide, several heavy metals, and even the antibiotic cephaloridine seem mediated, in part, by actions affecting the Cn system. Data which could suggest that the Cn system is an integrator/regulator of the cellular response by the organism to it`s environment is described.
Energy absorption at cellular levels from curium isotopes deposited in the lung tissue
Curium isotopes are generated hitherto as a waste product in nuclear energy production. Exposure in humans has occured mainly via inhalation. After reprocessing of spent reactor fuel these nuclides represent the highest alpha activity during the first 60 years. Therefore it is necessary to study the resulting radiation exposure in man after a accidental contamination. Lung tissue sections were analysed for histological characteristics by means of adaptive pattern recognition methods, using an electronic image analyzer. Alpha particle tracks were superimposed and interaction with cellular structures was simulated. Cell frequency distribution, along with specific hit-probability is used to assess quantitatively the resulting energy deposition in the single cells
Euclidean Distances, soft and spectral Clustering on Weighted Graphs
Bavaud, François
2010-01-01
We define a class of Euclidean distances on weighted graphs, enabling to perform thermodynamic soft graph clustering. The class can be constructed form the "raw coordinates" encountered in spectral clustering, and can be extended by means of higher-dimensional embeddings (Schoenberg transformations). Geographical flow data, properly conditioned, illustrate the procedure as well as visualization aspects.
Smoothed analysis of partitioning algorithms for Euclidean functionals
Bläser, Markus; Manthey, Bodo; Rao, B.V. Raghavendra
2013-01-01
Euclidean optimization problems such as TSP and minimum-length matching admit fast partitioning algorithms that compute near-optimal solutions on typical instances. In order to explain this performance, we develop a general framework for the application of smoothed analysis to partitioning algorithm
From geometry to algebra: the Euclidean way with technology
Ferrarello, Daniela; Flavia Mammana, Maria; Pennisi, Mario
2016-05-01
In this paper, we present the results of an experimental classroom activity, history-based with a phylogenetic approach, to achieve algebra properties through geometry. In particular, we used Euclidean propositions, processed them by a dynamic geometry system and translate them into algebraic special products.
The toroidal Hausdorff dimension of 2d Euclidean quantum gravity
Ambjorn, Jan; Budd, Timothy George
2013-01-01
The lengths of shortest non-contractible loops are studied numerically in 2d Euclidean quantum gravity on a torus coupled to conformal field theories with central charge less than one. We find that the distribution of these geodesic lengths displays a scaling in agreement with a Hausdorff dimension...
Gravitation in 4D Euclidean Space-Time Geometry
Winkler, Franz-Guenter
2007-01-01
The Euclidean interpretation of special relativity provides an intuitive way to understand and derive the Lorentz transformations in the framework of a "natural" 4D Euclidean space-time geometry. In this article the conceptual basis for a purely metric generalization of the Euclidean view is laid. It consists of i) the assumption of spatial and directional variations of the speed of light (VSL), ii) a formulation of the principle of general covariance in 4D Euclidean geometry, and iii) a generally covariant motion law for point particles. For the gravitation model, which is developed on this basis, three out of four effects of the Schwarzschild solution are derived (shift of spectral lines, deflection of light, precession of perihelia of planetary orbits). The explanation of the Shapiro radar echo delay requires modifications of the space-time geometry of the sun's environment. The additional effects brought forth by the respective model entail a possible account of the coronal heating problem and thus make t...
The Role of Structure in Learning Non-Euclidean Geometry
Asmuth, Jennifer A.
2009-01-01
How do people learn novel mathematical information that contradicts prior knowledge? The focus of this thesis is the role of structure in the acquisition of knowledge about hyperbolic geometry, a non-Euclidean geometry. In a series of three experiments, I contrast a more holistic structure--training based on closed figures--with a mathematically…
Euclidean Primes Have the Minimum Number of Primitive Roots
Křížek, Michal; Somer, L.
2008-01-01
Roč. 12, č. 1 (2008), s. 121-127. ISSN 0972-5555 R&D Projects: GA AV ČR(CZ) IAA100190803 Institutional research plan: CEZ:AV0Z10190503 Keywords : Euclidean prime s * Fermat prime s * Sophie Germain prime s Subject RIV: BA - General Mathematics
Since low dose effects of alpha particles are produced by cellular hits in a relatively small fraction of exposed cells, the present study focuses on alpha particle interactions in bronchial epithelial cells following exposure to inhaled radon progeny. A computer code was developed for the calculation of microdosimetric spectra, dose and hit probabilities for alpha particles emitted from uniform and non-uniform source distributions in cylindrical and Y-shaped bronchial airway geometries. Activity accumulations at the dividing spur of bronchial airway bifurcations produce hot spots of cellular hits, indicating that a small fraction of cells located at such sites may receive substantially higher doses. While presently available data on in vitro transformation frequencies suggest that the relative biological effectiveness for alpha particles ranges from about 3 to 10, the effect of inhomogeneous activity distributions of radon progeny may slightly increase the radiation weighting factor relative to a uniform distribution. Thus a radiation weighting factor of about 10 may be more realistic than the current value of 20, at least for lung cancer risk following inhalation of short-lived radon progeny. (authors)
Vaughan, Herbert E.; Szabo, Steven
This is the teacher's edition of a text for the second year of a two-year high school geometry course. The course bases plane and solid geometry and trigonometry on the fact that the translations of a Euclidean space constitute a vector space which has an inner product. Congruence is a geometric topic reserved for Volume 2. Volume 2 opens with an…
Biharmonic Submanifolds with Parallel Mean Curvature Vector in Pseudo-Euclidean Spaces
Fu, Yu, E-mail: yufudufe@gmail.com [Dongbei University of Finance and Economics, School of Mathematics and Quantitative Economics (China)
2013-12-15
In this paper, we investigate biharmonic submanifolds in pseudo-Euclidean spaces with arbitrary index and dimension. We give a complete classification of biharmonic spacelike submanifolds with parallel mean curvature vector in pseudo-Euclidean spaces. We also determine all biharmonic Lorentzian surfaces with parallel mean curvature vector field in pseudo-Euclidean spaces.
Werner, Hofmann; Hatim, Fakir [Salzburg Univ., Div. of Physics and Biophysics, Dept. of Material Science (Austria); Lucia-Adina, Truta-Popa [Babes-Bolyai Univ., Faculty of Physics (Romania)
2006-07-01
To explore the role of the multiplicity of cellular hits by radon progeny alpha particles for lung cancer incidence, the number of single and multiple alpha particle hits were computed for basal and secretory cells in the bronchial epithelium of human airway bifurcations employing Monte Carlo methods. Hot spots of alpha particle hits were observed at the branching points of bronchial airway bifurcations, suggesting that multiple alpha particle hits may occur primarily at carinal ridges. Random alpha particle intersections of bronchial cells during a given exposure period, selected from a Poisson distribution, were simulated by an initiation-promotion model, based on experimentally observed cellular transformation and survival functions. To consider potential bystander effects, which have been observed in cellular in vitro studies, alpha particle interactions were also simulated for larger sensitive target volumes in bronchial epithelium, consisting of a collection of cells. Lung cancer risk simulations indicated that cancer induction for continuous exposures is related to the cycle time of an irradiated cell, thus exhibiting a distinct dose-rate effect. While the dominant role of single hits leads to a linear dose-response relationship at low radon exposure levels, predicted lung cancer risk for a collection of interacting cells exhibits a linear-quadratic response, suggesting that bystander effects, if operating at all under in vivo irradiations, may be restricted to a small number of adjacent cells. (author)
To explore the role of the multiplicity of cellular hits by radon progeny alpha particles for lung cancer incidence, the number of single and multiple alpha particle hits were computed for basal and secretory cells in the bronchial epithelium of human airway bifurcations employing Monte Carlo methods. Hot spots of alpha particle hits were observed at the branching points of bronchial airway bifurcations, suggesting that multiple alpha particle hits may occur primarily at carinal ridges. Random alpha particle intersections of bronchial cells during a given exposure period, selected from a Poisson distribution, were simulated by an initiation-promotion model, based on experimentally observed cellular transformation and survival functions. To consider potential bystander effects, which have been observed in cellular in vitro studies, alpha particle interactions were also simulated for larger sensitive target volumes in bronchial epithelium, consisting of a collection of cells. Lung cancer risk simulations indicated that cancer induction for continuous exposures is related to the cycle time of an irradiated cell, thus exhibiting a distinct dose-rate effect. While the dominant role of single hits leads to a linear dose-response relationship at low radon exposure levels, predicted lung cancer risk for a collection of interacting cells exhibits a linear-quadratic response, suggesting that bystander effects, if operating at all under in vivo irradiations, may be restricted to a small number of adjacent cells. (author)
Cellular-level near-wall unsteadiness of high-hematocrit erythrocyte flow using confocal μPIV
Patrick, Michael J.; Chen, Chia-Yuan; Frakes, David H.; Dur, Onur; Pekkan, Kerem
2011-04-01
In hemodynamics, the inherent intermittency of two-phase cellular-level flow has received little attention. Unsteadiness is reported and quantified for the first time in the literature using a combination of fluorescent dye labeling, time-resolved scanning confocal microscopy, and micro-particle image velocimetry (μPIV). The near-wall red blood cell (RBC) motion of physiologic high-hematocrit blood in a rectangular microchannel was investigated under pressure-driven flow. Intermittent flow was associated with (1) the stretching of RBCs as they passed through RBC clusters with twisting motions; (2) external flow through local obstacles; and (3) transitionary rouleaux formations. Velocity profiles are presented for these cases. Unsteady flow clustered in local regions. Extra-cellular fluid flow generated by individual RBCs was examined using submicron fluorescent microspheres. The capabilities of confocal μPIV post-processing were verified using synthetic raw PIV data for validation. Cellular interactions and oscillating velocity profiles are presented, and 3D data are made available for computational model validation.
Cellular-level near-wall unsteadiness of high-hematocrit erythrocyte flow using confocal {mu}PIV
Patrick, Michael J. [Carnegie Mellon University, Molecular Biosensor and Imaging Center (MBIC), Pittsburgh, PA (United States); Chen, Chia-Yuan; Dur, Onur; Pekkan, Kerem [Carnegie Mellon University, Department of Biomedical and Mechanical Engineering, Pittsburgh, PA (United States); Frakes, David H. [Arizona State University, School of Biological and Health Systems Engineering and School of Electrical, Computer, and Energy Engineering, Tempe, AZ (United States)
2011-04-15
In hemodynamics, the inherent intermittency of two-phase cellular-level flow has received little attention. Unsteadiness is reported and quantified for the first time in the literature using a combination of fluorescent dye labeling, time-resolved scanning confocal microscopy, and micro-particle image velocimetry ({mu}PIV). The near-wall red blood cell (RBC) motion of physiologic high-hematocrit blood in a rectangular microchannel was investigated under pressure-driven flow. Intermittent flow was associated with (1) the stretching of RBCs as they passed through RBC clusters with twisting motions; (2) external flow through local obstacles; and (3) transitionary rouleaux formations. Velocity profiles are presented for these cases. Unsteady flow clustered in local regions. Extra-cellular fluid flow generated by individual RBCs was examined using submicron fluorescent microspheres. The capabilities of confocal {mu}PIV post-processing were verified using synthetic raw PIV data for validation. Cellular interactions and oscillating velocity profiles are presented, and 3D data are made available for computational model validation. (orig.)
Mendes, Luís André; Maria, Vera L; Scott-Fordsmand, Janeck J; Amorim, Mónica J B
2015-10-01
The effects of nanomaterials have been primarily assessed based on standard ecotoxicity guidelines. However, by adapting alternative measures the information gained could be enhanced considerably, e.g., studies should focus on more mechanistic approaches. Here, the environmental risk posed by the presence of silver nanoparticles (Ag NM300K) in soil was investigated, anchoring population and cellular level effects, i.e., survival, reproduction (28 days) and oxidative stress markers (0, 2, 4, 6, 10 days). The standard species Folsomia candida was used. Measured markers included catalase (CAT), glutathione reductase (GR), glutathione S-transferase (GST), total glutathione (TG), metallothionein (MT) and lipid peroxidation (LPO). Results showed that AgNO₃ was more toxic than AgNPs at the population level: reproduction EC₂₀ and EC₅₀ was ca. 2 and 4 times lower, respectively. At the cellular level Correspondence Analysis showed a clear separation between AgNO₃ and AgNP throughout time. Results showed differences in the mechanisms, indicating a combined effect of released Ag⁺ (MT and GST) and of AgNPs (CAT, GR, TG, LPO). Hence, clear advantages from mechanistic approaches are shown, but also that time is of importance when measuring such responses. PMID:26473892
Luís André Mendes
2015-10-01
Full Text Available The effects of nanomaterials have been primarily assessed based on standard ecotoxicity guidelines. However, by adapting alternative measures the information gained could be enhanced considerably, e.g., studies should focus on more mechanistic approaches. Here, the environmental risk posed by the presence of silver nanoparticles (Ag NM300K in soil was investigated, anchoring population and cellular level effects, i.e., survival, reproduction (28 days and oxidative stress markers (0, 2, 4, 6, 10 days. The standard species Folsomia candida was used. Measured markers included catalase (CAT, glutathione reductase (GR, glutathione S-transferase (GST, total glutathione (TG, metallothionein (MT and lipid peroxidation (LPO. Results showed that AgNO3 was more toxic than AgNPs at the population level: reproduction EC20 and EC50 was ca. 2 and 4 times lower, respectively. At the cellular level Correspondence Analysis showed a clear separation between AgNO3 and AgNP throughout time. Results showed differences in the mechanisms, indicating a combined effect of released Ag+ (MT and GST and of AgNPs (CAT, GR, TG, LPO. Hence, clear advantages from mechanistic approaches are shown, but also that time is of importance when measuring such responses.
Palmieri, Michelle; Nowell, Cameron J; Condron, Melanie; Gardiner, James; Holmes, Andrew B; Desai, Jayesh; Burgess, Antony W; Catimel, Bruno
2010-11-01
We have developed an immunocytochemistry method for the semiquantitative detection of phosphatidylinositol (3,4,5)-trisphosphate (PI(3,4,5)P3) at the cell plasma membrane. This protocol combines the use of a glutathione S-transferase-tagged pleckstrin homology (PH) domain of the general phosphoinositides-1 receptor (GST-GRP1PH) with fluorescence confocal microscopy and image segmentation using cell mask software analysis. This methodology allows the analysis of PI(3,4,5)P3 subcellular distribution in resting and epidermal growth factor (EGF)-stimulated HEK293T cells and in LIM1215 (wild-type phosphoinositide 3-kinase (PI3K)) and LIM2550 (H1047R mutation in PI3K catalytic domain) colonic carcinoma cells. Formation of PI(3,4,5)P3 was observed 5min following EGF stimulation and resulted in an increase of the membrane/cytoplasm fluorescence ratio from 1.03 to 1.53 for HEK293T cells and from 2.2 to 3.3 for LIM1215 cells. Resting LIM2550 cells stained with GST-GRP1PH had an elevated membrane/cytoplasm fluorescence ratio of 9.8, suggesting constitutive PI3K activation. The increase in the membrane/cytoplasm fluorescent ratio was inhibited in a concentration-dependent manner by the PI3K inhibitor LY294002. This cellular confocal imaging assay can be used to directly assess the effects of PI3K mutations in cancer cell lines and to determine the potential specificity and effectiveness of PI3K inhibitors in cancer cells. PMID:20599646
In this study we analyzed the cellular stress levels achieved by heat shock proteins (HSP) 90 and 70 in rat thyroid tissue after exposure to radio waves in TWG experimental system. Parallel measurements of body stress in animals by rectal temperature probes allow us to determine whether there is any interaction between temperature increases and cellular stress.
Lorentz connection from a conformal gauge theory of Euclidean space
Hazboun, Jeffrey S
2013-01-01
The quotient of the conformal group of Euclidean 4-space by its Weyl subgroup results in a geometry possessing many of the properties of relativistic phase space, including both a natural symplectic form and non-degenerate Killing metric. When we complete the identification with phase space by requiring the existence of orthogonal, canonically conjugate, metric submanifolds, we find that the induced metric and the spin connection are Lorentzian on the submanifolds, despite the Euclidean starting pont. By examining the structure equations of the biconformal space in an orthonormal frame adapted to its phase space properties, we also find that two new tensor fields emerge from this geometry. The first is a combination of the scale factor on the metric with the Weyl vector. The second comes from the components of the spin connection, symmetric with respect to the new metric. Though this field comes from the spin connection it transforms homogeneously.
Embedding spacetime via a geodesically equivalent metric of Euclidean signature
Jonsson, Rickard
2001-01-01
Starting from the equations of motion in a 1 + 1 static, diagonal, Lorentzian spacetime, such as the Schwarzschild radial line element, I find another metric, but with Euclidean signature, which produces the same geodesics x(t). This geodesically equivalent, or dual, metric can be embedded in ordinary Euclidean space. On the embedded surface freely falling particles move on the shortest path. Thus one can visualize how acceleration in a gravitational field is explained by particles moving freely in a curved spacetime. Freedom in the dual metric allows us to display, with substantial curvature, even the weak gravity of our Earth. This may provide a nice pedagogical tool for elementary lectures on general relativity. I also study extensions of the dual metric scheme to higher dimensions. In an addendum I extend the analysis concerning the shape of an embedding of the dual spacetime of a line through a planet of constant proper density.
In this work we propose an exact microscopic description of maximally symmetric branes in a euclidean AdS3 background. As shown by Bachas and Petropoulos, the most important such branes are localized along a euclidean AdS2 is contained in AdS3. We provide explicit formulas for the coupling of closed strings to such branes (boundary states) and for the spectral density of open strings. The latter is computed in two different ways first in terms of the open string reflection amplitude and then also from the boundary states by world-sheet duality. This gives rise to an important Cardy type consistency check. All the results are compared in detail with the geometrical picture. We also discuss a second class of branes with spherical symmetry and finally comment on some implications for D-branes in a 2D back hole geometry. (author)
Classification of Handwritten Marathi Numbers Using Euclidean Distance
A. Kaousadikar
2012-05-01
Full Text Available In this paper we propose a system for recognition of Marathi handwritten numbers. In this system we develop an algorithm in which we employed Euclidean distance technique for recognition. This algorithm tested on our own database in which we collected 0-9 handwritten Marathi numbers and this handwritten numbers converted in digitization using scanner of brand UMAX model Astra 5600. The handwritten font size of each numbers for each person is different and we made same size, by comparing query/test image of number with database image of numbers by removing rows and columns from bigger size of row and column. Also we compare two techniques of removing rows and columns from centre and removed rows and columns from outer sides (i.e. from top, bottom, left and right side of database images of numbers for calculation of Euclidean distance. The algorithm tested in Matlab tool and the result is shown in table.
Learning to Detect Spam: Naive-Euclidean Approach
Tony Y.T. Chan
2008-12-01
Full Text Available A method is proposed for learning to classify spam and nonspamemails. It combines the strategy of the Best Stepwise Feature Selection with a classifier of Euclidean nearest-neighbor. Each text email is first transformed into a vector of D-dimensional Euclidean space. Emails were divided into training and test sets in the manner of 10-fold crossvalidation. Three experiments were performed, and their elapsed CPU times and accuracies reported. The proposed spam detection learner was found to be extremely fast in recognition and with good error rates. It could be used as a baseline learning agent, in terms of CPU time and accuracy, against which other learning agents can be measured.
Active biopolymer networks generate scale-free but euclidean clusters
Sheinman, M; Alvarado, J; Koenderink, G H; MacKintosh, F C
2014-01-01
We report analytical and numerical modelling of active elastic networks, motivated by experiments on crosslinked actin networks contracted by myosin motors. Within a broad range of parameters, the motor-driven collapse of active elastic networks leads to a critical state. We show that this state is qualitatively different from that of the random percolation model. Intriguingly, it possesses both euclidean and scale-free structure with Fisher exponent smaller than $2$. Remarkably, an indistinguishable Fisher exponent and the same euclidean structure is obtained at the critical point of the random percolation model after absorbing all enclaves into their surrounding clusters. We propose that in the experiment the enclaves are absorbed due to steric interactions of network elements. We model the network collapse, taking into account the steric interactions. The model shows how the system robustly drives itself towards the critical point of the random percolation model with absorbed enclaves, in agreement with th...
Primordial scalar power spectrum from the Euclidean big bounce
Schander, Susanne; Barrau, Aurélien; Bolliet, Boris; Linsefors, Linda; Mielczarek, Jakub; Grain, Julien
2016-01-01
In effective models of loop quantum cosmology, the holonomy corrections are associated with deformations of space-time symmetries. The most evident manifestation of the deformations is the emergence of a Euclidean phase accompanying the nonsingular bouncing dynamics of the scale factor. In this article, we compute the power spectrum of scalar perturbations generated in this model, with a massive scalar field as the matter content. Instantaneous and adiabatic vacuum-type initial conditions for scalar perturbations are imposed in the contracting phase. The evolution through the Euclidean region is calculated based on the extrapolation of the time direction pointed by the vectors normal to the Cauchy hypersurface in the Lorentzian domains. The obtained power spectrum is characterized by a suppression in the IR regime and oscillations in the intermediate energy range. Furthermore, the speculative extension of the analysis in the UV reveals a specific rise of the power leading to results incompatible with the data.
Short-distance analysis for algebraic euclidean field theory
Schlingemann, D
1999-01-01
Recently D. Buchholz and R. Verch have proposed a method for implementing in algebraic quantum field theory ideas from renormalization group analysis of short-distance (high energy) behavior by passing to certain scaling limit theories. Buchholz and Verch distinguish between different types of theories where the limit is unique, degenerate, or classical, and the method allows in principle to extract the `ultraparticle' content of a given model, i.e. to identify particles (like quarks and gluons) that are not visible at finite distances due to `confinement'. It is therefore of great importance for the physical interpretation of the theory. The method has been illustrated in a simple model in with some rather surprising results. This paper will focus on the question how the short distance behavior of models defined by euclidean means is reflected in the corresponding behavior of their Minkowski counterparts. More specifically, we shall prove that if a euclidean theory has some short distance limit, then it is p...
Euclidean dynamical symmetry in nuclear shape phase transitions
The Euclidean dynamical symmetry hidden in the critical region of nuclear shape phase transitions is revealed by a novel algebraic F(5) description. With a nonlinear projection, it is shown that the dynamics in the critical region of the spherical–axial deformed and the spherical–γ-soft shape phase transitions can indeed be manifested by this description, which thus provides a unified symmetry-based interpretation of the critical phenomena in the region.
Change of Measure between Light Travel Time and Euclidean Distances
Heymann Y.
2013-04-01
Full Text Available The problem of cosmological distances is approached using a method based on the propagation of light in an expanding Universe. From the chan ge of measure between Light Travel Time and Euclidean Distances, a formula is deri ved to compute distances as a function of redshift. This formula is identical to Matti g’s formula (with q 0 = 1 / 2 which is based on Friedmann’s equations of general relativi ty.
General Nth order integrals of motion in the Euclidean plane
Post, S.; Winternitz, P.
2015-10-01
The general form of an integral of motion that is a polynomial of order N in the momenta is presented for a Hamiltonian system in two-dimensional Euclidean space. The classical and the quantum cases are treated separately, emphasizing both the similarities and the differences between the two. The main application will be to study Nth order superintegrable systems that allow separation of variables in the Hamilton-Jacobi and Schrödinger equations, respectively.
General Nth order integrals of motion in the Euclidean plane
The general form of an integral of motion that is a polynomial of order N in the momenta is presented for a Hamiltonian system in two-dimensional Euclidean space. The classical and the quantum cases are treated separately, emphasizing both the similarities and the differences between the two. The main application will be to study Nth order superintegrable systems that allow separation of variables in the Hamilton–Jacobi and Schrödinger equations, respectively. (paper)
Dynamics of Induced Surfaces in Four-Dimensional Euclidean Space
Bracken, Paul
2006-01-01
The Davey Stewartson hierarchy will be developed based on a set of three matrix differential operators. These equations will act as evolution equations for different types of surface deformation in Euclidean four space. The Weierstrass representation for surfaces will be developed and its uniqueness up to gauge transformations will be reviewed. Applications of the hierarchy will be given with regard to generating deformations of surfaces, and it will be shown that the Willmore functional is p...
Friezes and a construction of the euclidean cluster variables
Assem, I.; Dupont, G.
2010-01-01
Let $Q$ be an euclidean quiver. Using friezes in the sense of Assem-Reutenauer-Smith, we provide an algorithm for computing the (canonical) cluster character associated to any object in the cluster category of $Q$. In particular, this algorithm allows to compute all the cluster variables in the cluster algebra associated to $Q$. It also allows to compute the sum of the Euler characteristics of the quiver grassmannians of any module $M$ over the path algebra of $Q$.
Upper Bounds for the Euclidean Operator Radius and Applications
2009-02-01
Full Text Available The main aim of the present paper is to establish various sharp upper bounds for the Euclidean operator radius of an n-tuple of bounded linear operators on a Hilbert space. The tools used are provided by several generalizations of Bessel inequality due to Boas-Bellman, Bombieri, and the author. Natural applications for the norm and the numerical radius of bounded linear operators on Hilbert spaces are also given.
Upper Bounds for the Euclidean Operator Radius and Applications
Dragomir SS
2008-01-01
Full Text Available Abstract The main aim of the present paper is to establish various sharp upper bounds for the Euclidean operator radius of an -tuple of bounded linear operators on a Hilbert space. The tools used are provided by several generalizations of Bessel inequality due to Boas-Bellman, Bombieri, and the author. Natural applications for the norm and the numerical radius of bounded linear operators on Hilbert spaces are also given.
Quantum Brans-Dicke Gravity in Euclidean Path Integral Formulation
Kim, Hongsu
1997-01-01
The conformal structure of Brans-Dicke gravity action is carefully studied. It is discussed that Brans-Dicke gravity action has definitely no conformal invariance. It is shown, however, that this lack of conformal invariance enables us to demonstrate that Brans-Dicke theory appears to have a better short-distance behavior than Einstein gravity as far as Euclidean path integral formulation for quantum gravity is concerned.
Defects and boundary layers in non-Euclidean plates
Gemmer, John
2012-01-01
We investigate the behaviour of non-Euclidean plates with constant negative Gaussian curvature using the F\\"oppl-von K\\'arm\\'an reduced theory of elasticity. Motivated by recent experimental results, we focus on annuli with a periodic profile. We prove rigorous upper and lower bounds for the elastic energy that scales like the thickness squared. We also investigate the scaling with thickness of boundary layers where the stretching energy is concentrated with decreasing thickness.
Euclidean Configuration Space Renormalization, Residues and Dilation Anomaly
Nikolov, Nikolay M; Todorov, Ivan
2013-01-01
Configuration (x-)space renormalization of Euclidean Feynman amplitudes in a massless quantum field theory is reduced to the study of local extensions of associate homogeneous distributions. Primitively divergent graphs are renormalized, in particular, by subtracting the residue of an analytically regularized expression. Examples are given of computing residues that involve zeta values. The renormalized Green functions are again associate homogeneous distributions of the same degree that transform under indecomposable representations of the dilation group.
Modified Euclidean Algorithms for Decoding Reed-Solomon Codes
Sarwate, Dilip V.; Yan, Zhiyuan
2009-01-01
The extended Euclidean algorithm (EEA) for polynomial greatest common divisors is commonly used in solving the key equation in the decoding of Reed-Solomon (RS) codes, and more generally in BCH decoding. For this particular application, the iterations in the EEA are stopped when the degree of the remainder polynomial falls below a threshold. While determining the degree of a polynomial is a simple task for human beings, hardware implementation of this stopping rule is more complicated. This p...
Euclidean Upgrade from a Minimal Number of Segments
Schilling, Tanja; Pajdla, Tomas
2013-01-01
In this paper, we propose an algebraic approach to upgrade a projective reconstruction to a Euclidean one, and aim at computing the rectifying homography from a minimal number of 9 segments of known length. Constraints are derived from these segments which yield a set of polynomial equations that we solve by means of Gr\\"obner bases. We explain how a solver for such a system of equations can be constructed from simplified template data. Moreover, we present experiments that demonstrate that t...
The workshop ''International Workshop on Radiation Risk and its Origin at Molecular and Cellular Level'' was held at The Tokai Research Establishment, Japan Atomic Energy Research Institute, on the 6th and 7th of February 2003. The Laboratory of Radiation Risk Analysis of JAERI organized it. This international workshop attracted scientists from several different scientific areas, including radiation physics, radiation biology, molecular biology, crystallography of biomolecules, modeling and bio-informatics. Several foreign and domestic keynote speakers addresses the very fundamental areas of radiation risk and tried to establish a link between the fundamental studies at the molecular and cellular level and radiation damages at the organism. The symposium consisted of 13 oral lectures, 10 poster presentations and panel discussion. The 108 participants attended the workshop. This publication comprises of proceedings of oral and poster presentations where available. For the rest of contributions the abstracts or/and selections of presentation materials are shown instead. The 5 papers are indexed individually. (J.P.N.)
Folding of non-Euclidean curved shells
Bende, Nakul; Evans, Arthur; Innes-Gold, Sarah; Marin, Luis; Cohen, Itai; Santangelo, Christian; Hayward, Ryan
2015-03-01
Origami-based folding of 2D sheets has been of recent interest for a variety of applications ranging from deployable structures to self-folding robots. Though folding of planar sheets follows well-established principles, folding of curved shells involves an added level of complexity due to the inherent influence of curvature on mechanics. In this study, we use principles from differential geometry and thin shell mechanics to establish fundamental rules that govern folding of prototypical creased shells. In particular, we show how the normal curvature of a crease line controls whether the deformation is smooth or discontinuous, and investigate the influence of shell thickness and boundary conditions. We show that snap-folding of shells provides a route to rapid actuation on time-scales dictated by the speed of sound. The simple geometric design principles developed can be applied at any length-scale, offering potential for bio-inspired soft actuators for tunable optics, microfluidics, and robotics. This work was funded by the National Science Foundation through EFRI ODISSEI-1240441 with additional support to S.I.-G. through the UMass MRSEC DMR-0820506 REU program.
Thermal conductivity of biological cells at cellular level and correlation with disease state
Park, Byoung Kyoo; Woo, Yunho; Jeong, Dayeong; Park, Jaesung; Choi, Tae-Youl; Simmons, Denise Perry; Ha, Jeonghong; Kim, Dongsik
2016-06-01
This paper reports the thermal conductivity k of matched pair cell lines: two pairs of a normal and a cancer cell, one pair of a primary and metastatic cell. The 3ω method with a nanoscale thermal sensor was used to measure k at the single-cell level. To observe the difference in k between normal and cancer cells, the measurements were conducted for Hs 578Bst/Hs 578 T (human breast cells) and TE 353.Sk/TE 354.T (human skin cells). Then k of WM-115/WM-266-4, a primary and metastatic pair of human skin cell, was measured to find the effect of disease progression on k. The measured k data for normal and disease cell samples show statistically meaningful differences. In all cases, k decreased as the disease progressed. This work shows that thermal-analysis schemes, such as the 3ω method, have a potential to detect diseases at the cell level.
Efficient Uplink Modeling for Dynamic System-Level Simulations of Cellular and Mobile Networks
Lobinger Andreas
2010-01-01
Full Text Available A novel theoretical framework for uplink simulations is proposed. It allows investigations which have to cover a very long (real- time and which at the same time require a certain level of accuracy in terms of radio resource management, quality of service, and mobility. This is of particular importance for simulations of self-organizing networks. For this purpose, conventional system level simulators are not suitable due to slow simulation speeds far beyond real-time. Simpler, snapshot-based tools are lacking the aforementioned accuracy. The runtime improvements are achieved by deriving abstract theoretical models for the MAC layer behavior. The focus in this work is long term evolution, and the most important uplink effects such as fluctuating interference, power control, power limitation, adaptive transmission bandwidth, and control channel limitations are considered. Limitations of the abstract models will be discussed as well. Exemplary results are given at the end to demonstrate the capability of the derived framework.
Kopp, C.; M. Pernice; Domart-Coulon, I.; Djediat, C.; J. E. Spangenberg; Alexander, D. T. L.; Hignette, M.; Meziane, T.; Meibom, A.
2013-01-01
ABSTRACT Metabolic interactions with endosymbiotic photosynthetic dinoflagellate Symbiodinium spp. are fundamental to reef-building corals (Scleractinia) thriving in nutrient-poor tropical seas. Yet, detailed understanding at the single-cell level of nutrient assimilation, translocation, and utilization within this fundamental symbiosis is lacking. Using pulse-chase 15N labeling and quantitative ion microprobe isotopic imaging (NanoSIMS; nanoscale secondary-ion mass spectrometry), we visualiz...
Low neural exosomal levels of cellular survival factors in Alzheimer’s disease
Goetzl, Edward J.; Boxer, Adam; Schwartz, Janice B.; Abner, Erin L; Petersen, Ronald C.; Miller, Bruce L.; Carlson, Olga D.; Mustapic, Maja; Kapogiannis, Dimitrios
2015-01-01
Transcription factors that mediate neuronal defenses against diverse stresses were quantified in plasma neural-derived exosomes of Alzheimer’s disease or frontotemporal dementia patients and matched controls. Exosomal levels of low-density lipoprotein receptor-related protein 6, heat-shock factor-1, and repressor element 1-silencing transcription factor all were significantly lower in Alzheimer’s disease patients than controls (P
Cellular and plasma levels of human glutaredoxin 1 and 2 detected by sensitive ELISA systems
Glutaredoxins (Grx) catalyze glutathione-dependent thiol-disulfide oxidoreduction reactions. Mammalian cells contain at least two dithiol glutaredoxins, the well-characterized cytoplasmic (12 kDa) Grx1 and the recently identified (18 kDa) Grx2 with mitochondrial and nuclear isoforms. We have developed two sensitive and specific sandwich ELISAs to study the levels of human Grx1 and Grx2. Both Grx1 and Grx2 were present in placenta extracts and in cell lysates prepared from various tumor cell lines. However, the levels of Grx1 were at least 20 times higher than those of Grx2. Plasma from healthy blood donors contained 13.4 ± 7.9 ng/ml of Grx1, while Grx2 was not detected. Unstimulated peripheral blood mononuclear cells were shown to secrete Grx1, but upon 12-O-tetradecanoylphorbol-13-acetate activation, the secretion of Grx1 was strongly suppressed. This effect was shown to occur at the transcriptional level. The secretion of Grx1 and its presence in plasma suggests extracellular functions as found for mammalian thioredoxin 1
Tumour hypoxia promotes radioresistance and is associated with poor prognosis. The transcription factor Aryl hydrocarbon receptor nuclear translocator (ARNT), also designated as Hypoxia-inducible factor (HIF)-1β, is part of the HIF pathway which mediates cellular adaptations to oxygen deprivation and facilitates tumour progression. The subunits HIF-1α and ARNT are key players within this pathway. HIF-1α is regulated in an oxygen-dependent manner whereas ARNT is considered to be constitutively expressed. However, there is mounting evidence that certain tumour cells are capable to elevate ARNT in hypoxia which suggests a survival benefit. Therefore the objective of this study was to elucidate effects of an altered ARNT expression level on the cellular response to radiation. Different human cell lines (Hep3B, MCF-7, 786-Owt, 786-Ovhl, RCC4wt and RCC4vhl) originating from various tumour entities (Hepatocellular carcinoma, breast cancer and renal cell carcinoma respectively) were X-irradiated using a conventional linear accelerator. Knockdown of ARNT expression was achieved by transient siRNA transfection. Complementary experiments were performed by forced ARNT overexpression using appropriate plasmids. Presence/absence of ARNT protein was confirmed by Western blot analysis. Clonogenic survival assays were performed in order to determine cellular survival post irradiation. Statistical comparison of two groups was achieved by the unpaired t-test. The results of this study indicate that ARNT depletion renders tumour cells susceptible to radiation whereas overexpression of this transcription factor confers radioresistance. These findings provide evidence to consider ARNT as a drug target and as a predictive marker in clinical applications concerning the response to radiation. The online version of this article (doi:10.1186/s13014-015-0539-9) contains supplementary material, which is available to authorized users
Regulatory Nexus of Synthesis and Degradation Deciphers Cellular Nrf2 Expression Levels
Suzuki, Takafumi; Shibata, Tatsuhiro; Takaya, Kai; Shiraishi, Kouya; Kohno, Takashi; Kunitoh, Hideo; Tsuta, Koji; Furuta, Koh; Goto, Koichi; Hosoda, Fumie; Sakamoto, Hiromi; Motohashi, Hozumi; Yamamoto, Masayuki
2013-01-01
Transcription factor Nrf2 (NF-E2-related factor 2) is essential for oxidative and electrophilic stress responses. While it has been well characterized that Nrf2 activity is tightly regulated at the protein level through proteasomal degradation via Keap1 (Kelch-like ECH-associated protein 1)-mediated ubiquitination, not much attention has been paid to the supply side of Nrf2, especially regulation of Nrf2 gene transcription. Here we report that manipulation of Nrf2 transcription is effective i...
Nabhan, Joseph F.; Gooch, Renea L.; Piatnitski Chekler, Eugene L.; Pierce, Betsy; Bulawa, Christine E.
2015-01-01
Friedreich’s Ataxia is a genetic disease caused by expansion of an intronic trinucleotide repeat in the frataxin (FXN) gene yielding diminished FXN expression and consequently disease. Since increasing FXN protein levels is desirable to ameliorate pathology, we explored the role of major cellular proteostasis pathways and mitochondrial proteases in FXN processing and turnover. We targeted p97/VCP, the ubiquitin proteasome pathway (UPP), and autophagy with chemical inhibitors in cell lines and patient-derived cells. p97 inhibition by DBeQ increased precursor FXN levels, while UPP and autophagic flux modulators had variable effects predominantly on intermediate FXN. Our data suggest that these pathways cannot be modulated to influence mature functional FXN levels. We also targeted known mitochondrial proteases by RNA interference and discovered a novel protease PITRM1 that regulates intermediate FXN levels. Treatment with the aforementioned chemical and genetic modulators did not have a differential effect in patient cells containing lower amounts of FXN. Interestingly, a number of treatments caused a change in total amount of FXN protein, without an effect on mature FXN. Our results imply that regulation of FXN protein levels is complex and that total amounts can be modulated chemically and genetically without altering the absolute amount of mature FXN protein. PMID:26671574
SYSTEM LEVEL SIMULATION FOR TWO TIER MACRO-FEMTO CELLULAR NETWORKS
Shiqi Xing
2014-12-01
Full Text Available LTE is an emerging wireless communication technology to provide high- speed data service for the mobile phones and data terminals. To improve indoor coverage and capacity Femtocells are included in 3GPP since Release 8. There is no common simulation platform is available for performance justification of LTEFemtocells. LTE-Sim is an object-oriented open source simulator which incorporates a complete protocol stack can be used for simulating two-tier macro-femto scenarios. To the best of our knowledge no paper provides the guideline to perform system level simulation of Femtocell networks. Here, in this paper Femtocells performance is evaluated in multi-Macrocells and multi-Femtocells environment with interference from Microcells and Macrocell users along with the scripting
Monitoring Astronaut Health at the Nanoscale Cellular Level Through the Eye
Ansari, Rafat R.; Singh, Bhim S.; Rovati, Luigi; Docchio, Franco; Sebag, Jerry
2000-01-01
A user friendly goggles-like head-mounted device equipped with a suite of instruments for several non-invasive and quantitative medical evaluation of the eye, skin, and brain is desired for monitoring the health of astronauts during space travel and exploration of neighboring and distant planets. Real-time non-invasive evaluation of the different structures within the above organs can provide indices of the health of not just these organs, but the entire body. The techniques such as dynamic light scattering (for the early detection of uveitis, cholesterol levels, cataract, changes in the vitreous and possibly Alzheimer's disease), corneal autofluorescence (to assess extracellular matrix biology e.g., in diabetes), optical activity measurements (of anterior ocular fluid to evaluate blood-glucose levels), laser Doppler velocimetry (to assess retinal, optic nerve, and choroidal blood flow), reflectometry/oximetry (for assessing ocular and central nervous system oxygen metabolism), optical coherence tomography (to determine retinal tissue microstructure) and possibly scanning laser technology (for intraocular tissue imaging and scanning) will he integrated into this compact device. Skin sensors will also be mounted on the portion of the device in contact with the periocular region. This will enable monitoring of body temperature, EEG, and electrolyte status. This device will monitor astronaut health during long-duration space travel by detecting aberrations from pre-established "nonns", enabling prompt diagnosis and possibly the initiation of early preventative/curative therapy. The non-invasive nature of the device technologies permits frequent repetition of tests, enabling real-time complete crew health monitoring. This device may ultimately be useful in tele-medicine to bring modern healthcare to under-served areas on Earth as well as in so-called "advanced" care settings (e.g. diabetes in the USA).
Lia R Edmunds
Full Text Available The c-Myc (Myc oncoprotein and AMP-activated protein kinase (AMPK regulate glycolysis and oxidative phosphorylation (Oxphos although often for different purposes. Because Myc over-expression depletes ATP with the resultant activation of AMPK, we explored the potential co-dependency of and cross-talk between these proteins by comparing the consequences of acute Myc induction in ampk+/+ (WT and ampk-/- (KO murine embryo fibroblasts (MEFs. KO MEFs showed a higher basal rate of glycolysis than WT MEFs and an appropriate increase in response to activation of a Myc-estrogen receptor (MycER fusion protein. However, KO MEFs had a diminished ability to increase Oxphos, mitochondrial mass and reactive oxygen species in response to MycER activation. Other differences between WT and KO MEFs, either in the basal state or following MycER induction, included abnormalities in electron transport chain function, levels of TCA cycle-related oxidoreductases and cytoplasmic and mitochondrial redox states. Transcriptional profiling of pathways pertinent to glycolysis, Oxphos and mitochondrial structure and function also uncovered significant differences between WT and KO MEFs and their response to MycER activation. Finally, an unbiased mass-spectrometry (MS-based survey capable of quantifying ~40% of all mitochondrial proteins, showed about 15% of them to be AMPK- and/or Myc-dependent in their steady state. Significant differences in the activities of the rate-limiting enzymes pyruvate kinase and pyruvate dehydrogenase, which dictate pyruvate and acetyl coenzyme A abundance, were also differentially responsive to Myc and AMPK and could account for some of the differences in basal metabolite levels that were also detected by MS. Thus, Myc and AMPK are highly co-dependent and appear to engage in significant cross-talk across numerous pathways which support metabolic and ATP-generating functions.
Erapaneedi, Raghu; Belousov, Vsevolod V; Schäfers, Michael; Kiefer, Friedemann
2016-01-01
Hypoxia is an intensively investigated condition with profound effects on cell metabolism, migration, and angiogenesis during development and disease. Physiologically, hypoxia is linked to tissue homeostasis and maintenance of pluripotency. Hypoxia also contributes to pathologies including cardiovascular diseases and cancer. Despite its importance, microscopic visualization of hypoxia is largely restricted to the detection of reductively activated probes by immunostaining. Here, we describe a novel family of genetically encoded fluorescent sensors that detect the activation of HIF transcription factors reported by the oxygen-independent fluorescent protein UnaG. It comprises sensors with different switching and memory behavior and combination sensors that allow the distinction of hypoxic and reoxygenated cells. We tested these sensors on orthotopically transplanted glioma cell lines. Using a cranial window, we could visualize hypoxia intravitally at cellular resolution. In tissue samples, sensor activity was detected in regions, which were largely devoid of blood vessels, correlated with HIF-1α stabilization, and were highly heterogeneous at a cellular level. Frequently, we detected recently reoxygenated cells outside hypoxic areas in the proximity of blood vessels, suggestive of hypoxia-promoted cell migration. PMID:26598532
In vivo method for the detection of somatic mutations at the cellular level in mice
Searle, A.G.; Stephenson, D.A. (Medical Research Council, Harwell (UK). Radiobiology Unit)
1982-01-01
This new method is based on the fact that recessive mutations at the dilute and leaden loci change the shape of pigment-cells in the hair follicles from their normal highly dendritic appearance to a rounded-up almost non-dendritic form. Gene action is autonomous and individual mutant melanocytes can be recognised in whole mounts of dorsal skin made after the post-natal onset of melanogenesis. Foetal heterozygotes for d and In were treated with X-rays (0-200 rad) or procarbazine (0-300 mg/kg body mass by maternal i.p. injection) 17 after detection of a vaginal plug; whole mounts of dorsal skin (fixed 3 after birth) were microscopically scanned for mutant melanocytes in the hair follicles. Mutant cells were mainly in the form of small intrafollicular clones; the few mounts containing large interfollicular clones were excluded from the analysis. For both treatments, dose-response relationships showed good fits to both a quadratic and a power-law curve. However, neither of these differed significantly from a square-law relationship. The estimated mutation rate at the 100 rad X-ray level of 4.7x10/sup -7//rad/locus was in good agreement with the literature. Possible ways in which the present method might be improved and extended are discussed.
An in vivo method for the detection of somatic mutations at the cellular level in mice
This new method is based on the fact that recessive mutations at the dilute and leaden loci change the shape of pigment-cells in the hair follicles from their normal highly dendritic appearance to a rounded-up almost non-dendritic form. Gene action is autonomous and individual mutant melanocytes can be recognised in whole mounts of dorsal skin made after the post-natal onset of melanogenesis. Foetal heterozygotes for d and In were treated with X-rays (0-200 rad) or procarbazine (0-300 mg/kg body mass by maternal i.p. injection) 17 after detection of a vaginal plug; whole mounts of dorsal skin (fixed 3 after birth) were microscopically scanned for mutant melanocytes in the hair follicles. Mutant cells were mainly in the form of small intrafollicular clones; the few mounts containing large interfollicular clones were excluded from the analysis. For both treatments, dose-response relationships showed good fits to both a quadratic and a power-law curve. However, neither of these differed significantly from a square-law relationship. The estimated mutation rate at the 100 rad X-ray level of 4.7x10-7/rad/locus was in good agreement with the literature. Possible ways in which the present method might be improved and extended are discussed. (orig./MG)
Tinnitus: pathology of synaptic plasticity at the cellular and system levels.
Guitton, Matthieu J
2012-01-01
Despite being more and more common, and having a high impact on the quality of life of sufferers, tinnitus does not yet have a cure. This has been mostly the result of limited knowledge of the biological mechanisms underlying this adverse pathology. However, the last decade has witnessed tremendous progress in our understanding on the pathophysiology of tinnitus. Animal models have demonstrated that tinnitus is a pathology of neural plasticity, and has two main components: a molecular, peripheral component related to the initiation phase of tinnitus; and a system-level, central component-related to the long-term maintenance of tinnitus. Using the most recent experimental data and the molecular/system dichotomy as a framework, we describe here the biological basis of tinnitus. We then discuss these mechanisms from an evolutionary perspective, highlighting similarities with memory. Finally, we consider how these discoveries can translate into therapies, and we suggest operative strategies to design new and effective combined therapeutic solutions using both pharmacological (local and systemic) and behavioral tools (e.g., using tele-medicine and virtual reality settings). PMID:22408611
Sonon, B.; François, B.; Massart, T. J.
2015-08-01
A general and widely tunable method for the generation of representative volume elements for cellular materials based on distance and level set functions is presented. The approach is based on random tessellations constructed from random inclusion packings. A general methodology to obtain arbitrary-shaped tessellations to produce disordered foams is presented and illustrated. These tessellations can degenerate either in classical Voronoï tessellations potentially additively weighted depending on properties of the initial inclusion packing used, or in Laguerre tessellations through a simple modification of the formulation. A versatile approach to control the particular morphology of the obtained foam is introduced. Specific local features such as concave triangular Plateau borders and non-constant thickness heterogeneous coatings can be built from the tessellation in a straightforward way and are tuned by a small set of parameters with a clear morphological interpretation.
Orientation Maps in V1 and Non-Euclidean Geometry.
Afgoustidis, Alexandre
2015-12-01
In the primary visual cortex, the processing of information uses the distribution of orientations in the visual input: neurons react to some orientations in the stimulus more than to others. In many species, orientation preference is mapped in a remarkable way on the cortical surface, and this organization of the neural population seems to be important for visual processing. Now, existing models for the geometry and development of orientation preference maps in higher mammals make a crucial use of symmetry considerations. In this paper, we consider probabilistic models for V1 maps from the point of view of group theory; we focus on Gaussian random fields with symmetry properties and review the probabilistic arguments that allow one to estimate pinwheel densities and predict the observed value of π. Then, in order to test the relevance of general symmetry arguments and to introduce methods which could be of use in modeling curved regions, we reconsider this model in the light of group representation theory, the canonical mathematics of symmetry. We show that through the Plancherel decomposition of the space of complex-valued maps on the Euclidean plane, each infinite-dimensional irreducible unitary representation of the special Euclidean group yields a unique V1-like map, and we use representation theory as a symmetry-based toolbox to build orientation maps adapted to the most famous non-Euclidean geometries, viz. spherical and hyperbolic geometry. We find that most of the dominant traits of V1 maps are preserved in these; we also study the link between symmetry and the statistics of singularities in orientation maps, and show what the striking quantitative characteristics observed in animals become in our curved models. PMID:26082007
In this Letter we discuss the analyticity properties of the Wilson-loop correlation functions relevant to the problem of soft high-energy scattering, directly at the level of the functional integral, in a genuinely nonperturbative way. The strategy is to start from the Euclidean theory and to push the dependence on the relevant variables θ (the relative angle between the loops) and T (the half-length of the loops) into the action by means of a field and coordinate transformation, and then to allow them to take complex values. In particular, we determine the analyticity domain of the relevant Euclidean correlation function, and we show that the corresponding Minkowskian quantity is recovered with the usual double analytic continuation in θ and T inside this domain. The formal manipulations of the functional integral are justified making use of a lattice regularisation. The new rescaled action so derived could also be used directly to get new insights (from first principles) in the problem of soft high-energy scattering.
Euclidean D-branes and higher-dimensional gauge theory
We consider euclidean D-branes wrapping around manifolds of exceptional holonomy in dimensions seven and eight. The resulting theory on the D-brane-that is, the dimensional reduction of 10-dimensional supersymmetric Yang-Mills theory-is a cohomological field theory which describes the topology of the moduli space of instantons. The 7-dimensional theory is an NT=2 (or balanced) cohomological theory given by an action potential of Chern-Simons type. As a by-product of this method, we construct a related cohomological field theory which describes the monopole moduli space on a 7-manifold of G2 holonomy. (author). 22 refs, 3 tabs
Divisibility tests and recurring decimals in Euclidean domains
Khare, Apoorva
2004-01-01
In this article, we try to explain and unify standard divisibility tests found in various books. We then look at recurring decimals, and list a few of their properties. We show how to compute the number of digits in the recurring part of any fraction. Most of these results are accompanied by a proof (along with the assumptions needed), that works in a Euclidean domain. We then ask some obvious questions related to the results, and mention some similar questions that have been answered. In the...
Convergent perturbation expansions for Euclidean quantum field theory
Mayer perturbation theory is designed to provide computable convergent expansions which permit calculation of Greens functions in Euclidean Quantum Field Theory to arbitrary accuracy, including 'nonperturbative' contributions from large field fluctuations. Here we describe the expansions at the example of 3-dimensional lambdaphi4-theory (in continuous space). They are not essentially more complicated than standard perturbation theory. The n-th order term is expressed in terms of 0(n)-dimensional integrals, and is of order lambda4 if 4k-3<=n<=4k. (orig.)
Fast Approximation Algorithm for Restricted Euclidean Bottleneck Steiner Tree Problem
Zimao Li
2014-04-01
Full Text Available Bottleneck Steiner tree problem asks to find a Steiner tree for n terminals with at most k Steiner points such that the length of the longest edge in the tree is minimized. The problem has applications in the design of wireless communication networks. In this paper we study a restricted version of the bottleneck Steiner tree problem in the Euclidean plane which requires that only degree-2 Steiner points are possibly adjacent in the optimal solution. We first show that the problem is NP-hard and cannot be approximated within unless P=NP, and provide a fast polynomial time deterministic approximation algorithm with performance ratio .
Non-Euclidean classification of medically imaged objects via s-reps.
Hong, Junpyo; Vicory, Jared; Schulz, Jörn; Styner, Martin; Marron, J S; Pizer, Stephen M
2016-07-01
Classifying medically imaged objects, e.g., into diseased and normal classes, has been one of the important goals in medical imaging. We propose a novel classification scheme that uses a skeletal representation to provide rich non-Euclidean geometric object properties. Our statistical method combines distance weighted discrimination (DWD) with a carefully chosen Euclideanization which takes full advantage of the geometry of the manifold on which these non-Euclidean geometric object properties (GOPs) live. Our method is evaluated via the task of classifying 3D hippocampi between schizophrenics and healthy controls. We address three central questions. 1) Does adding shape features increase discriminative power over the more standard classification based only on global volume? 2) If so, does our skeletal representation provide greater discriminative power than a conventional boundary point distribution model (PDM)? 3) Especially, is Euclideanization of non-Euclidean shape properties important in achieving high discriminative power? Measuring the capability of a method in terms of area under the receiver operator characteristic (ROC) curve, we show that our proposed method achieves strongly better classification than both the classification method based on global volume alone and the s-rep-based classification method without proper Euclideanization of non-Euclidean GOPs. We show classification using Euclideanized s-reps is also superior to classification using PDMs, whether the PDMs are first Euclideanized or not. We also show improved performance with Euclideanized boundary PDMs over non-linear boundary PDMs. This demonstrates the benefit that proper Euclideanization of non-Euclidean GOPs brings not only to s-rep-based classification but also to PDM-based classification. PMID:26963609
Hasegawa, Sumitaka; Maruyama, Kouichi; Takenaka, Hikaru; Furukawa, Takako; Saga, Tsuneo
2009-08-18
The recent success with small fish as an animal model of cancer with the aid of fluorescence technique has attracted cancer modelers' attention because it would be possible to directly visualize tumor cells in vivo in real time. Here, we report a medaka model capable of allowing the observation of various cell behaviors of transplanted tumor cells, such as cell proliferation and metastasis, which were visualized easily in vivo. We established medaka melanoma (MM) cells stably expressing GFP and transplanted them into nonirradiated and irradiated medaka. The tumor cells were grown at the injection sites in medaka, and the spatiotemporal changes were visualized under a fluorescence stereoscopic microscope at a cellular-level resolution, and even at a single-cell level. Tumor dormancy and metastasis were also observed. Interestingly, in irradiated medaka, accelerated tumor growth and metastasis of the transplanted tumor cells were directly visualized. Our medaka model provides an opportunity to visualize in vivo tumor cells "as seen in a culture dish" and would be useful for in vivo tumor cell biology. PMID:19666513
Zeyer, Karina A; Reinhardt, Dieter P
2015-01-01
Fibrillins are the major components of microfibrils in the extracellular matrix of elastic and non-elastic tissues. They are multi-domain proteins, containing primarily calcium binding epidermal growth factor-like (cbEGF) domains and 8-cysteine/transforming growth factor-beta binding protein-like (TB) domains. Mutations in the fibrillin-1 gene give rise to Marfan syndrome, a connective tissue disorder with clinical complications in the cardiovascular, skeletal, ocular and other organ systems. Here, we review the consequences of engineered Marfan syndrome mutations in fibrillin-1 at the protein, cellular and organismal levels. Representative point mutations associated with Marfan syndrome in affected individuals have been introduced and analyzed in recombinant fibrillin-1 fragments. Those mutations affect fibrillin-1 on a structural and functional level. Mutations which impair folding of cbEGF domains can affect protein trafficking. Protein folding disrupted by some mutations can lead to defective secretion in mutant fibrillin-1 fragments, whereas fragments with other Marfan mutations are secreted normally. Many Marfan mutations render fibrillin-1 more susceptible to proteolysis. There is also evidence that some mutations affect heparin binding. Few mutations have been further analyzed in mouse models. An extensively studied mouse model of Marfan syndrome expresses mouse fibrillin-1 with a missense mutation (p.C1039G). The mice display similar characteristics to human patients with Marfan syndrome. Overall, the analyses of engineered mutations leading to Marfan syndrome provide important insights into the pathogenic molecular mechanisms exerted by mutated fibrillin-1. PMID:26281765
Quantum mechanics on manifolds embedded in Euclidean space
Quantum particles confined to surfaces in higher-dimensional spaces are acted upon by forces that exist only as a result of the surface geometry and the quantum mechanical nature of the system. The dynamics are particularly rich when confinement is implemented by forces that act normal to the surface. We review this confining potential formalism applied to the confinement of a particle to an arbitrary manifold embedded in a higher-dimensional Euclidean space. We devote special attention to the geometrically induced gauge potential that appears in the effective Hamiltonian for motion on the surface. We emphasize that the gauge potential is only present when the space of states describing the degrees of freedom normal to the surface is degenerate. We also distinguish between the effects of the intrinsic and extrinsic geometry on the effective Hamiltonian and provide simple expressions for the induced-scalar potential. We discuss examples including the case of a three-dimensional manifold embedded in a five-dimensional Euclidean space
The Einstein Constraint Equations on Asymptotically Euclidean Manifolds
Dilts, James
2015-01-01
In this dissertation, we prove a number of results regarding the conformal method of finding solutions to the Einstein constraint equations. These results include necessary and sufficient conditions for the Lichnerowicz equation to have solutions, global supersolutions which guarantee solutions to the conformal constraint equations for near-constant-mean-curvature (near-CMC) data as well as for far-from-CMC data, a proof of the limit equation criterion in the near-CMC case, as well as a model problem on the relationship between the asymptotic constants of solutions and the ADM mass. We also prove a characterization of the Yamabe classes on asymptotically Euclidean manifolds and resolve the (conformally) prescribed scalar curvature problem on asymptotically Euclidean manifolds for the case of nonpositive scalar curvatures. Many, though not all, of the results in this dissertation have been previously published in [Dilts13b], [DIMM14], [DL14], [DM15], and [DGI15]. This article is the author's Ph.D. dissertation...
On the Decidability of Connectedness Constraints in 2D and 3D Euclidean Spaces
Kontchakov, Roman; Pratt-Hartmann, Ian; Zakharyaschev, Michael
2011-01-01
We investigate (quantifier-free) spatial constraint languages with equality, contact and connectedness predicates as well as Boolean operations on regions, interpreted over low-dimensional Euclidean spaces. We show that the complexity of reasoning varies dramatically depending on the dimension of the space and on the type of regions considered. For example, the logic with the interior-connectedness predicate (and without contact) is undecidable over polygons or regular closed sets in the Euclidean plane, NP-complete over regular closed sets in three-dimensional Euclidean space, and ExpTime-complete over polyhedra in three-dimensional Euclidean space.
On the Complexity of the Minimum Latency Scheduling Problem on the Euclidean Plane
Lin, Henry
2012-01-01
We show NP-hardness of the minimum latency scheduling (MLS) problem under the physical model of wireless networking. In this model a transmission is received successfully if the Signal to Interference-plus-Noise Ratio (SINR), is above a given threshold. In the minimum latency scheduling problem, the goal is to assign a time slot and power level to each transmission, so that all the messages are received successfully, and the number of distinct times slots is minimized. Despite its seeming simplicity and several previous hardness results for various settings of the minimum latency scheduling problem, it has remained an open question whether or not the minimum latency scheduling problem is NP-hard, when the nodes are placed in the Euclidean plane and arbitrary power levels can be chosen for the transmissions. We resolve this open question for all path loss exponent values $\\alpha \\geq 3$.
Dahmani, Hassen-Reda; Schneeberger, Patricia; Kramer, IJsbrand M.
2009-01-01
The number of experimentally derived structures of cellular components is rapidly expanding, and this phenomenon is accompanied by the development of a new semiotic system for teaching. The infographic approach is shifting from a schematic toward a more realistic representation of cellular components. By realistic we mean artist-prepared or…
Rats receiving a nutritionally deficient diet displayed markedly elevated serum free T3 levels but showed no increase in oxygen consumption. This was associated with greatly reduced ratios of hepatic cellular and nuclear /sub 125/I-T3 to serum /sub 125/I-T3. Kinetic data supported the conclusion that cellular uptake of T3 was decreased in the nutritionally deficient rats. The lack of metabolic effect, despite the elevated serum T3 levels, is attributable to reduced availability of serum T3 to tissue nuclear receptor sites
Lee, Hye-Rim; Shon, Oog-Jin; Park, Se-Il; Kim, Han-Jun; Kim, Sukyoung; Ahn, Myun-Whan; Do, Sun Hee
2016-01-01
Despite the susceptibility to frequent intrinsic and extrinsic injuries, especially in the inner zone, the meniscus does not heal spontaneously owing to its poor vascularity. In this study, the effect of platelet-rich plasma (PRP), containing various growth factors, on meniscal mechanisms was examined under normal and post-traumatic inflammatory conditions. Isolated primary meniscal cells of New Zealand white (NZW) rabbits were incubated for 3, 10, 14 and 21 days with PRP(−), 10% PRP (PRP(+)), IL(+) or IL(+)PRP(+). The meniscal cells were collected and examined using reverse-transcription polymerase chain reaction (RT-PCR). Culture media were examined by immunoblot analyses for matrix metalloproteinases (MMP) catabolic molecules. PRP containing growth factors improved the cellular viability of meniscal cells in a concentration-dependent manner at Days 1, 4 and 7. However, based on RT-PCR, meniscal cells demonstrated dedifferentiation, along with an increase in type I collagen in the PRP(+) and in IL(+)PRP(+). In PRP(+), the aggrecan expression levels were lower than in the PRP(−) until Day 21. The protein levels of MMP-1 and MMP-3 were higher in each PRP group, i.e., PRP(+) and IL(+)PRP(+), at each culture time. A reproducible 2-mm circular defect on the meniscus of NZW rabbit was used to implant fibrin glue (control) or PRP in vivo. After eight weeks, the lesions in the control and PRP groups were occupied with fibrous tissue, but not with meniscal cells. This study shows that PRP treatment of the meniscus results in an increase of catabolic molecules, especially those related to IL-1α-induced inflammation, and that PRP treatment for an in vivo meniscus injury accelerates fibrosis, instead of meniscal cartilage. PMID:26784189
BPS Wilson loops in Minkowski spacetime and Euclidean space
Ouyang, Hao; Wu, Jun-Bao; Zhang, Jia-ju [Chinese Academy of Sciences, Theoretical Physics Division, Institute of High Energy Physics, Beijing (China); Chinese Academy of Sciences, Theoretical Physics Center for Science Facilities, Beijing (China)
2015-12-15
We give evidence that spacelike BPS Wilson loops do not exist in Minkowski spacetime. We show that spacelikeWilson loops in Minkowski spacetime cannot preserve any supersymmetries, in d = 4 N = 4 super Yang-Mills theory, d = 3 N = 2 super Chern-Simons-matter theory, and d = 3 N = 6 Aharony-Bergman-Jafferis- Maldacena theory. We not only show this using infinite straight lines and circles as examples, but also we give proofs for general curves. We attribute this to the conflicts of the reality conditions of the spinors. However, spacelike Wilson loops do exist in Euclidean space. There are both BPS Wilson loops along infinite straight lines and circular BPS Wilson loops. This is because the reality conditions of the spinors are lost after Wick rotation. The result is reasonable in view of the AdS/CFT correspondence. (orig.)
BPS Wilson loops in Minkowski spacetime and Euclidean space
Ouyang, Hao; Wu, Jun-Bao; Zhang, Jia-ju
2015-12-01
We give evidence that spacelike BPS Wilson loops do not exist in Minkowski spacetime. We show that spacelike Wilson loops in Minkowski spacetime cannot preserve any supersymmetries, in d = 4 N = 4 super Yang-Mills theory, d = 3 N = 2 super Chern-Simons-matter theory, and d = 3 N = 6 Aharony-Bergman-Jafferis-Maldacena theory. We not only show this using infinite straight lines and circles as examples, but also we give proofs for general curves. We attribute this to the conflicts of the reality conditions of the spinors. However, spacelike Wilson loops do exist in Euclidean space. There are both BPS Wilson loops along infinite straight lines and circular BPS Wilson loops. This is because the reality conditions of the spinors are lost after Wick rotation. The result is reasonable in view of the AdS/CFT correspondence.
Susceptible-Infected-Recovered model on Euclidean network
Khaleque, Abdul
2012-01-01
We consider the Susceptible-Infected-Recovered (SIR) epidemic model on a Euclidean network in one dimension in which nodes at a distance $l$ are connected with probability $P(l) \\propto l^{-\\delta}$ in addition to nearest neighbors. The topology of the network changes as $\\delta$ is varied and its effect on the SIR model is studied. $R(t)$, the recovered fraction of population up to time $t$, and $\\tau$, the total duration of the epidemic are calculated for different values of the infection probability $q$ and $\\delta$. A threshold behavior is observed for all $\\delta$ up to $\\delta \\approx 2.0$; above the threshold value $q = q_c$, the saturation value $R_{sat}$ attains a finite value. Both $R_{sat}$ and $\\tau $ show scaling behavior in a finite system of size $N$; $R_{sat} \\sim N^{-\\beta/{\\tilde{\
On continuous expansions of configurations of points in Euclidean space
Cheng, Holun; Zheng, Yidan
2011-01-01
For any two configurations of ordered points $p=(p_{1},...,\\p_{N})$ and $q=(q_{1},...,q_{N})$ in Euclidean space $E^d$ such that $q$ is an expansion of $p$, there exists a continuous expansion from $p$ to $q$ in dimension 2d; Bezdek and Connelly used this to prove the Kneser-Poulsen conjecture for the planar case. In this paper, we show that this construction is optimal in the sense that for any $d \\ge 2$ there exists configurations of $(d+1)^2$ points $p$ and $q$ in $E^d$ such that $q$ is an expansion of $p$ but there is no continuous expansion from $p$ to $q$ in dimension less than 2d. The techniques used in our proof are completely elementary.
Entangling gates in even Euclidean lattices such as Leech lattice
Planat, Michel
2010-01-01
We point out a organic relationship between real entangling n-qubit gates of quantum computation and the group of automorphisms of even Euclidean lattices of the corresponding dimension 2n. The type of entanglement that is found in the gates/generators of Aut() depends on the lattice. In particular, we investigate Zn lattices, Barnes-Wall lattices D4, E8, 16 (associated to n = 2, 3 and 4 qubits), and the Leech lattices h24 and 24 (associated to a 3-qubit/qutrit system). Balanced tripartite entanglement is found to be a basic feature of Aut(), a nding that bears out our recent work related to the Weyl group of E8 [1, 2].
Modified Euclidean Algorithms for Decoding Reed-Solomon Codes
Sarwate, Dilip V
2009-01-01
The extended Euclidean algorithm (EEA) for polynomial greatest common divisors is commonly used in solving the key equation in the decoding of Reed-Solomon (RS) codes, and more generally in BCH decoding. For this particular application, the iterations in the EEA are stopped when the degree of the remainder polynomial falls below a threshold. While determining the degree of a polynomial is a simple task for human beings, hardware implementation of this stopping rule is more complicated. This paper describes a modified version of the EEA that is specifically adapted to the RS decoding problem. This modified algorithm requires no degree computation or comparison to a threshold, and it uses a fixed number of iterations. Another advantage of this modified version is in its application to the errors-and-erasures decoding problem for RS codes where significant hardware savings can be achieved via seamless computation.
Nearly Optimal Solution for Restricted Euclidean Bottleneck Steiner Tree Problem
Zimao Li
2014-04-01
Full Text Available A variation of the traditional Steiner tree problem, the bottleneck Steiner tree problem is considered in this paper, which asks to find a Steiner tree for n terminals with at most k Steiner points such that the length of the longest edge in the tree is minimized. The problem has applications in the design of WDM optical networks, design of wireless communication networks and reconstruction of phylogenetic tree in biology. We study a restricted version of the bottleneck Steiner tree problem in the Euclidean plane which requires that only degree-2 Steiner points are possibly adjacent in the optimal solution. The problem is known to be MAX-SNP hard and cannot be approximated within unless P=NP, we propose a nearly optimal randomized polynomial time approximation algorithm with performance ratio +e, where e is a positive number.
BPS Wilson loops in Minkowski spacetime and Euclidean space
Ouyang, Hao, E-mail: ouyangh@ihep.ac.cn; Wu, Jun-Bao, E-mail: wujb@ihep.ac.cn; Zhang, Jia-ju, E-mail: jjzhang@ihep.ac.cn [Theoretical Physics Division, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Rd, 100049, Beijing (China); Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, 19B Yuquan Rd, 100049, Beijing (China)
2015-12-21
We give evidence that spacelike BPS Wilson loops do not exist in Minkowski spacetime. We show that spacelike Wilson loops in Minkowski spacetime cannot preserve any supersymmetries, in d=4N=4 super Yang–Mills theory, d=3N=2 super Chern–Simons-matter theory, and d=3N=6 Aharony–Bergman–Jafferis–Maldacena theory. We not only show this using infinite straight lines and circles as examples, but also we give proofs for general curves. We attribute this to the conflicts of the reality conditions of the spinors. However, spacelike Wilson loops do exist in Euclidean space. There are both BPS Wilson loops along infinite straight lines and circular BPS Wilson loops. This is because the reality conditions of the spinors are lost after Wick rotation. The result is reasonable in view of the AdS/CFT correspondence.
The Euclidean Algorithm for Generalized Minimum Distance Decoding of Reed-Solomon Codes
Kampf, Sabine
2010-01-01
This paper presents a method to merge Generalized Minimum Distance decoding of Reed-Solomon codes with the extended Euclidean algorithm. By merge, we mean that the steps taken to perform the Generalized Minimum Distance decoding are similar to those performed by the extended Euclidean algorithm. The resulting algorithm has a complexity of O(n^2).
Euclidean wormholes with Phantom field and Phantom field accompanied by perfect fluid
Darabi, F.
2010-01-01
We study the classical Euclidean wormhole solutions for the gravitational systems with minimally coupled pure Phantom field and minimally coupled Phantom field accompanied by perfect fluid. It is shown that such solutions do exist and then the general forms of the Phantom field potential are obtained for which there are classical Euclidean wormhole solutions.
The Dirac Eigenvalues as Observables of N=2 D=4 Euclidean Supergravity
Vancea, I V
2004-01-01
We generalize previous works on the Dirac eigenvalues as dynamical variables of the Euclidean gravity in four dimensions to N=2 D=4 Euclidean supergravity. We define the Poisson brackets in the covariant phase space of the theory and compute them for the Dirac eigenvalues.
10D to 4D Euclidean Supergravity over a Calabi-Yau three-fold
Sabra, Wafic
2015-01-01
We dimensionally reduce the bosonic sector of 10D Euclidean type IIA supergravity over a Calabi-Yau three-fold. The resulting theory describes the bosonic sector of 4D, N = 2 Euclidean supergravity coupled to vector- and hyper-multiplets.
Split quaternions and semi-Euclidean projective spaces
In this study, we give one-to-one correspondence between the elements of the unit split three-sphere S(3,2) with the complex hyperbolic special unitary matrices SU(2,1). Thus, we express spherical concepts such as meridians of longitude and parallels of latitude on SU(2,1) by using the method given in Toth [Toth G. Glimpses of algebra and geometry. Springer-Verlag; 1998] for S3. The relation among the special orthogonal group SO(R3), the quotient group of unit quaternions S3/{±1} and the projective space RP3 given as SO(R3)≅S3/{±1}=RP3 is known as the Euclidean projective spaces [Toth G. Glimpses of algebra and geometry. Springer-Verlag; 1998]. This relation was generalized to the semi-Euclidean projective space and then, the expression SO(3,1)≅S(3,2)/{±1}=RP23 was acquired. Thus, it was found that Hopf fibriation map of S(2,1) can be used for Twistors (in not-null state) in quantum mechanics applications. In addition, the octonions and the split-octonions can be obtained from the Cayley-Dickson construction by defining a multiplication on pairs of quaternions or split quaternions. The automorphism group of the octonions is an exceptional Lie group. The split-octonions are used in the description of physical law. For example, the Dirac equation in physics (the equation of motion of a free spin 1/2 particle, like e.g. an electron or a proton) can be represented by a native split-octonion arithmetic.
A general Euclidean connection for so(n,m) lie algebra and the algebraic approach to scattering
We obtain a general Euclidean connection for so(n,m). This Euclidean connection allows an algebraic derivation of the S matrix and it reduces to the known one in suitable circumstances. (author). 8 refs
Song, J H; An, N; Chatterjee, S; Kistner-Griffin, E; Mahajan, S; Mehrotra, S; Kraft, A S
2015-07-01
The Pim protein kinases contribute to transformation by enhancing the activity of oncogenic Myc and Ras, which drives significant metabolic changes during tumorigenesis. In this report, we demonstrate that mouse embryo fibroblasts (MEFs) lacking all three isoforms of Pim protein kinases, triple knockout (TKO), cannot tolerate the expression of activated K-Ras (K-Ras(G12V)) and undergo cell death. Transduction of K-Ras(G12V) into these cells markedly increased the level of cellular reactive oxygen species (ROS). The addition of N-acetyl cysteine attenuated ROS production and reversed the cytotoxic effects of K-Ras(G12V) in the TKO MEFs. The altered cellular redox state caused by the loss of Pim occurred as a result of lower levels of metabolic intermediates in the glycolytic and pentose phosphate pathways as well as abnormal mitochondrial oxidative phosphorylation. TKO MEFs exhibit reduced levels of superoxide dismutase (Sod), glutathione peroxidase 4 (Gpx4) and peroxiredoxin 3 (Prdx3) that render them susceptible to killing by K-Ras(G12V)-mediated ROS production. In contrast, the transduction of c-Myc into TKO cells can overcome the lack of Pim protein kinases by regulating cellular metabolism and Sod2. In the absence of the Pim kinases, c-Myc transduction permitted K-Ras(G12V)-induced cell growth by decreasing Ras-induced cellular ROS levels. These results demonstrate that the Pim protein kinases have an important role in regulating cellular redox, metabolism and K-Ras-stimulated cell growth. PMID:25241892
Singh, Shailendra P; Miller, Haley L; Montgomery, Beronda L
2013-10-14
Fremyella diplosiphon alters the phycobiliprotein composition of its light-harvesting complexes, i.e., phycobilisomes, and its cellular morphology in response to changes in the prevalent wavelengths of light in the external environment in a phenomenon known as complementary chromatic acclimation (CCA). The organism primarily responds to red light (RL) and green light (GL) during CCA to maximize light absorption for supporting optimal photosynthetic efficiency. Recently, we found that RL-characteristic spherical cell morphology is associated with higher levels of reactive oxygen species (ROS) compared to growth under GL where lower ROS levels and rectangular cell shape are observed. The RL-dependent association of increased ROS levels with cellular morphology was demonstrated by treating cells with a ROS-scavenging antioxidant which resulted in the observation of GL-characteristic rectangular morphology under RL. To gain additional insights into the involvement of ROS in impacting cellular morphology changes during CCA, we conducted experiments to study the temporal dynamics of changes in ROS levels and cellular morphology during transition to growth under RL or GL. Alterations in ROS levels and cell morphology were found to be correlated with each other at early stages of acclimation of low white light-grown cells to growth under high RL or cells transitioned between growth in RL and GL. These results provide further general evidence that significant RL-dependent increases in ROS levels are temporally correlated with changes in morphology toward spherical. Future studies will explore the light-dependent mechanisms by which ROS levels may be regulated and the direct impacts of ROS on the observed morphology changes. PMID:24122367
Antoniadou, Zoi-Anna; Hezka, Johana; Kousiappa, Ioanna; Mamais, Ioannis; Skoura, Lemonia; Pilalas, Dimitris; Metallidis, Simeon; Nicolaidis, Pavlos; Malisiovas, Nicolaos; Kostrikis, Leondios G
2014-03-01
The emergence of resistance against current antiretroviral drugs to human immunodeficiency virus type 1 (HIV-1) is an increasingly important concern to the continuous success of antiretroviral therapy to HIV-1-infected patients. In the past decade, a number of studies reported that the prevalence of transmitted drug resistance among newly diagnosed patients has reached an overall 9% prevalence worldwide. Also, a number of studies using longitudinal HIV-1 patient study cohorts demonstrated that the cellular HIV-1 DNA level in peripheral blood mononuclear cells (PBMCs) has a prognostic value for the progression of HIV-1 disease independently of plasma HIV-1 RNA load and CD4 count. Using a previously established molecular-beacon-based real-time PCR methodology, cellular HIV-1 DNA levels were quantified in newly diagnosed and antiretroviral-naive patients in Northern Greece recruited between 2009 and 2010 using a predefined enrolling strategy, in an effort to investigate whether there is any relationship between cellular HIV-1 DNA levels and HIV-1 transmitted drug resistance. As part of the same study, DNA sequences encoding the env (C2-C5 region of gp120) were also amplified from PBMC-extracted DNA in order to determine the genotypic coreceptor tropism and genetic subtype. Cellular HIV-1 DNA levels had a median of 3.309 log10 HIV-1 copies per 10(6) PBMCs and demonstrated no correlation between cellular HIV-1 DNA levels and HIV-1 transmitted drug resistance. An absence of association between cellular HIV-1 DNA levels with plasma viral HIV-1 RNA load and CD4 levels was also found reconfirming the previously published study. Genotypic analysis of coreceptor tropism indicated that 96% of samples, independently of the presence or not of genotypic drug resistance, were CCR5-tropic. Overall, the findings reconfirmed the previously proposed proposition that transmitted drug resistance does not have an impact on disease progression in HIV-1-infected individuals. Also, CCR5
Intrinsic flat stability of the positive mass theorem for graphical hypersurfaces of Euclidean space
Huang, Lan-Hsuan; Sormani, Christina
2014-01-01
The rigidity of the Positive Mass Theorem states that the only complete asymptotically flat manifold of nonnegative scalar curvature and zero mass is Euclidean space. We study the stability of this statement for spaces that can be realized as graphical hypersurfaces in Euclidean space. We prove (under certain technical hypotheses) that if a sequence of complete asymptotically flat graphs of nonnegative scalar curvature has mass approaching zero, then the sequence must converge to Euclidean space in the pointed intrinsic flat sense. The appendix includes a new Gromov-Hausdorff and intrinsic flat compactness theorem for sequences of metric spaces with uniform Lipschitz bounds on their metrics.
On the complexity of some quadratic Euclidean 2-clustering problems
Kel'manov, A. V.; Pyatkin, A. V.
2016-03-01
Some problems of partitioning a finite set of points of Euclidean space into two clusters are considered. In these problems, the following criteria are minimized: (1) the sum over both clusters of the sums of squared pairwise distances between the elements of the cluster and (2) the sum of the (multiplied by the cardinalities of the clusters) sums of squared distances from the elements of the cluster to its geometric center, where the geometric center (or centroid) of a cluster is defined as the mean value of the elements in that cluster. Additionally, another problem close to (2) is considered, where the desired center of one of the clusters is given as input, while the center of the other cluster is unknown (is the variable to be optimized) as in problem (2). Two variants of the problems are analyzed, in which the cardinalities of the clusters are (1) parts of the input or (2) optimization variables. It is proved that all the considered problems are strongly NP-hard and that, in general, there is no fully polynomial-time approximation scheme for them (unless P = NP).
Balancing Degree, Diameter and Weight in Euclidean Spanners
Solomon, Shay
2011-01-01
In this paper we devise a novel \\emph{unified} construction of Euclidean spanners that trades between the maximum degree, diameter and weight gracefully. For a positive integer k, our construction provides a (1+eps)-spanner with maximum degree O(k), diameter O(log_k n + alpha(k)), weight O(k \\cdot log_k n \\cdot log n) \\cdot w(MST(S)), and O(n) edges. Note that for k= n^{1/alpha(n)} this gives rise to diameter O(alpha(n)), weight O(n^{1/alpha(n)} \\cdot log n \\cdot alpha(n)) \\cdot w(MST(S)) and maximum degree O(n^{1/alpha(n)}), which improves upon a classical result of Arya et al. \\cite{ADMSS95}; in the corresponding result from \\cite{ADMSS95} the spanner has the same number of edges and diameter, but its weight and degree may be arbitrarily large. Also, for k = O(1) this gives rise to maximum degree O(1), diameter O(log n) and weight O(log^2 n) \\cdot w(MST(S)), which reproves another classical result of Arya et al. \\cite{ADMSS95}. Our bound of O(log_k n + alpha(k)) on the diameter is optimal under the constrai...
Marion Le Coadic
Full Text Available Dictyostelium discoideum has largely been used to study phagocytosis and intracellular killing of bacteria. Previous studies have shown that Phg1A, Kil1 and Kil2 proteins are necessary for efficient intracellular killing of Klebsiella bacteria. Here we show that in phg1a KO cells, cellular levels of lysosomal glycosidases and lysozyme are decreased, and lysosomal pH is increased. Surprisingly, overexpression of Kil1 restores efficient killing in phg1a KO cells without correcting these lysosomal anomalies. Conversely, kil1 KO cells are defective for killing, but their enzymatic content and lysosomal pH are indistinguishable from WT cells. The killing defect of phg1a KO cells can be accounted for by the observation that in these cells the stability and the cellular amount of Kil1 are markedly reduced. Since Kil1 is the only sulfotransferase characterized in Dictyostelium, an (unidentified sulfated factor, defective in both phg1a and kil1 KO cells, may play a key role in intracellular killing of Klebsiella bacteria. In addition, Phg1B plays a redundant role with Phg1A in controlling cellular amounts of Kil1 and intracellular killing. Finally, cellular levels of Kil1 are unaffected in kil2 KO cells, and Kil1 overexpression does not correct the killing defect of kil2 KO cells, suggesting that Kil2 plays a distinct role in intracellular killing.
Tohmola, Niina
2015-01-01
Metabolites are low molecular weight compounds participating in different functions of cellular systems. Metabolites can be used as diagnostic biomarkers for numerous diseases. Liquid chromatography tandem mass spectrometry (LC-MS/MS) is a powerful tool in quantification of metabolites from various sample matrices. Good sensitivity and specificity are the main benefits of the technique. Mass spectrometry is commonly used in industry, drug research and clinical diagnostics. Extensive validatio...
Scattering solutions of Bethe-Salpeter equation in Minkowski and Euclidean spaces
Carbonell, J
2016-01-01
We shortly review different methods to obtain the scattering solutions of the Bethe-Salpeter equation in Minkowski space. We emphasize the possibility to obtain the zero energy observables in terms of the Euclidean scattering amplitude.
Singularities of lightlike hypersurface in semi-Euclidean 4-space with index 2
无
2010-01-01
Anti de Sitter space is a maximally symmetric, vacuum solution of Einstein’s field equation with an attractive cosmological constant, and is the hyperquadric of semi-Euclidean space with index 2. So it is meaningful to study the submanifold in semi-Euclidean 4-space with index 2. However, the research on the submanifold in semi-Euclidean 4-space with index 2 has not been found from theory of singularity until now. In this paper, as a generalization of the study on lightlike hypersurface in Minkowski space and a preparation for the further study on anti de Sitter space, the singularities of lightlike hypersurface and Lorentzian surface in semi- Euclidean 4-space with index 2 will be studied. To do this, we reveal the relationships between the singularity of distance-squared function and that of lightlike hypersurface. In addition some geometric properties of lightlike hypersurface and Lorentzian surface are studied from geometrical point of view.
The Euclidean quantisation of Kerr-Newman-de Sitter black holes
Chrusciel, Piotr; Hörzinger, Michael
2016-01-01
We study the family of Einstein-Maxwell instantons associated with the Kerr-Newman metrics with a positive cosmological constant. This leads to a quantisation condition on the masses, charges, and angular momentum parameters of the resulting Euclidean solutions.
Asymptotic analysis of fundamental solutions of Dirac operators on even dimensional Euclidean spaces
We analyze the short distance asymptotic behavior of some quantities formed out of fundamental solutions of Dirac operators on even dimensional Euclidean spaces with finite dimensional matrix-valued potentials. (orig.)
Objective: To study the relationship between the cellular uptake of 99Tcm-MIBI and 99Tcm-tetrofosmin and the Pgp expression levels in four carcinoma cell lines, and the effect of quinidine on the uptake. Methods: 99Tcm-MIBI and 99Tcm-tetrofosmin were used as radioactive tracers to study the uptake kinetics in the carcinoma cell lines Hela, MCF-7, Bca61 and Mcf-7/Adr, and the effect of quinidine on the uptake of 99Tcm-MIBI and 99Tcm-tetrofosmin. The Pgp expression levels in carcinoma cell lines were estimated by using immunocytochemical method. Results: The cellular uptake of both 99Tcm-MIBI and 99Tcm-tetrofosmin was remarkably lower in MCF-7/Adr which gave a strong positive reaction in the Pgp immunocytochemical assay than Hela, MCF-7 and Bca61 did, which gave negative reactions in the immunocytochemical assay. Furthermore, the cellular uptake of 99Tcm-MIBI was higher than that of 99Tcm-tetrofosmin in the three Pgp negative carcinoma cell lines. The uptake of 99Tcm-MIBI and 99Tcm-tetrofosmin exhibited a 3.5 fold and a 4.3 fold increase respectively in the presence of quinidine. Conclusions: The cellular uptake of these two univalent cationic fat-soluble medicines in carcinoma cell lines is negatively correlated with the Pgp expression levels in the cells. Similar to 99Tcm-MIBI, 99Tcm-tetrofosmin seems also to be a good candidate as a noninvasive marker for the diagnosis of multi-drug resistance (MDR) relating to the Pgp levels in tumors. Quinidine can inhibit the drug resistance of MCF-7/Adr in some degree
Euclidean Geometry Codes, minimum weight words and decodable error-patterns using bit-flipping
Høholdt, Tom; Justesen, Jørn; Jonsson, Bergtor
2005-01-01
We determine the number of minimum wigth words in a class of Euclidean Geometry codes and link the performance of the bit-flipping decoding algorithm to the geometry of the error patterns.......We determine the number of minimum wigth words in a class of Euclidean Geometry codes and link the performance of the bit-flipping decoding algorithm to the geometry of the error patterns....