LENUS (Irish Health Repository)
Huber, Heinrich J
2010-01-01
ABSTRACT: BACKGROUND: Apoptosis is an essential cell death process throughout the entire life span of all metazoans and its deregulation in humans has been implicated in many proliferative and degenerative diseases. Mitochondrial outer membrane permeabilisation (MOMP) and activation of effector caspases are key processes during apoptosis signalling. MOMP can be subject to spatial coordination in human cancer cells, resulting in intracellular waves of cytochrome-c release. To investigate the consequences of these spatial anisotropies in mitochondrial permeabilisation on subsequent effector caspase activation, we devised a mathematical reaction-diffusion model building on a set of partial differential equations. RESULTS: Reaction-diffusion modelling suggested that even if strong spatial anisotropies existed during mitochondrial cytochrome c release, these would be eliminated by free diffusion of the cytosolic proteins that instantiate the apoptosis execution network. Experimentally, rapid sampling of mitochondrial permeabilisation and effector caspase activity in individual HeLa cervical cancer cells confirmed predictions of the reaction-diffusion model and demonstrated that the signalling network of apoptosis execution could efficiently translate spatial anisotropies in mitochondrial permeabilisation into a homogeneous effector caspase response throughout the cytosol. Further systems modelling suggested that a more than 10,000-fold impaired diffusivity would be required to maintain spatial anisotropies as observed during mitochondrial permeabilisation until the time effector caspases become activated. CONCLUSIONS: Multi-protein diffusion efficiently contributes to eliminating spatial asynchronies which are present during the initiation of apoptosis execution and thereby ensures homogeneous apoptosis execution throughout the entire cell body. For previously reported biological scenarios in which effector caspase activity was shown to be targeted selectively to
The Initial State of a Primordial Anisotropic Stage of Inflation
Energy Technology Data Exchange (ETDEWEB)
Blanco-Pillado, Jose J. [Department of Theoretical Physics, University of the Basque Country UPV/EHU,48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science,Maria Diaz de Haro 3, 48013 Bilbao (Spain); Minamitsuji, Masato [Yukawa Institute for Theoretical Physics, Kyoto University,Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502 (Japan); CENTRA, Instituto Superior Tecnico, Universidade de Lisboa,Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)
2015-06-12
We investigate the possibility that the inflationary period in the early universe was preceded by a primordial stage of strong anisotropy. In particular we focus on the simplest model of this kind, where the spacetime is described by a non-singular Kasner solution that quickly evolves into an isotropic de Sitter space, the so-called Kasner-de Sitter solution. The initial Big Bang singularity is replaced, in this case, by a horizon. We show that the extension of this metric to the region behind the horizon contains a timelike singularity which will be visible by cosmological observers. This makes it impossible to have a reliable prediction of the quantum state of the cosmological perturbations in the region of interest. In this paper we consider the possibility that this Kasner-de Sitter universe is obtained as a result of a quantum tunneling process effectively substituting the region behind the horizon by an anisotropic parent vacuum state, namely a 1+1 dimensional spacetime compactified over an internal flat torus, T{sub 2}, which we take it to be of the form de Sitter{sub 2}×T{sub 2} or Minkowski{sub 2}×T{sub 2}. As a first approximation to understand the effects of this anisotropic initial state, we compute the power spectrum of a massless scalar field in these backgrounds. In both cases, the spectrum converges at small scales to the isotropic scale invariant form and only present important deviations from it at the largest possible scales. We find that the decompactification scenario from M{sub 2}×T{sub 2} leads to a suppressed and slightly anisotropic power spectrum at large scales which could be related to some of the anomalies present in the current CMB data. On the other hand, the spectrum of the universe with a dS{sub 2}×T{sub 2} parent vacuum presents an enhancement in power at large scales not consistent with observations.
Majhi, S.; Pal, P. C.; Kumar, S.
2017-01-01
This study investigates the reflection and transmission of plane SH-waves in two semi-infinite anisotropic magnetoelastic media. The lower half-space is considered as initially stressed and inhomogeneous. The density of lower half-space is taken exponentially varying with depth. The solutions for half-spaces are obtained analytically. The expressions for reflection and transmission coefficient are obtained in the closed form subject to continuity conditions at the interfaces of anisotropic magnetoelastic half-spaces and the Snell's law. It is found that these coefficients depend on the initial stress, inhomogeneity parameter, the magnetoelastic coupling parameter, and the angle at which wave crosses the magnetic field of the half-spaces. Numerical computations are performed for these coefficients for a specific model of two different anisotropic magnetoelastic half-spaces. The numerical results are illustrated by the graph of reflection and transmission coefficient versus the angle of incidence. In general, as the initial stress increases the reflection and transmission coefficient increases, the affect is more prominent for more than 10 GPa. Inhomogeneity in the density of the material also increases the reflection and transmission coefficient. The anisotropic magnetoelastic parameter and the angle at which the wave crosses the magnetic field for both the half-spaces have a quite significant effect on the reflection and transmission coefficient.
Majhi, S.; Pal, P. C.; Kumar, S.
2016-06-01
This study investigates the reflection and transmission of plane SH-waves in two semi-infinite anisotropic magnetoelastic media. The lower half-space is considered as initially stressed and inhomogeneous. The density of lower half-space is taken exponentially varying with depth. The solutions for half-spaces are obtained analytically. The expressions for reflection and transmission coefficient are obtained in the closed form subject to continuity conditions at the interfaces of anisotropic magnetoelastic half-spaces and the Snell's law. It is found that these coefficients depend on the initial stress, inhomogeneity parameter, the magnetoelastic coupling parameter, and the angle at which wave crosses the magnetic field of the half-spaces. Numerical computations are performed for these coefficients for a specific model of two different anisotropic magnetoelastic half-spaces. The numerical results are illustrated by the graph of reflection and transmission coefficient versus the angle of incidence. In general, as the initial stress increases the reflection and transmission coefficient increases, the affect is more prominent for more than 10 GPa. Inhomogeneity in the density of the material also increases the reflection and transmission coefficient. The anisotropic magnetoelastic parameter and the angle at which the wave crosses the magnetic field for both the half-spaces have a quite significant effect on the reflection and transmission coefficient.
Constitutive relation of weakly anisotropic polycrystal with microstructure and initial stress
Institute of Scientific and Technical Information of China (English)
Mojia Huang; Hua Zhan; Xiuqiao Lin; Hai Tang
2007-01-01
Man (Nondestr Test Eval 15:191-214, 1999) derived the constitutive relation of a weakly-textured orthorhombic aggregate of cubic crystallites with effects of microstructure and initial stress. In this paper, a computational expression on the integration ∫SO(3)Qh× Dl m0 is given. Then, by means of the computational expression, the general constitutive relation of a weakly-textured anisotropic polycrystal with the consideration of microstructure and initial stress is derived. As special cases of our general constitutive relation, two constitutive relations are given for an isotropic polycrystal and a weakly-textured anisotropic aggregate of cubic crystallites. The acoustoelastic tensor of the reference cubic crystal is derived to determine the material constants of the polycrystal. Two examples are given for understanding the physical meaning of the texture coefficients and the constitutive relations.
Institute of Scientific and Technical Information of China (English)
Wang Zhigang; Li Yachun
2012-01-01
The aim of this paper is to prove the well-posedness (existence and uniqueness)of the Lp entropy solution to the homogeneous Dirichlet problems for the anisotropic degenerate parabolic-hyperbolic equations with Lp initial value.We use the device of doubling variables and some technical analysis to prove the uniqueness result.Moreover we can prove that the Lp entropy solution can be obtained as the limit of solutions of the corresponding regularized equations of nondegenerate parabolic type.
Effect of initial stress on reflection at the free surface of anisotropic elastic medium
Indian Academy of Sciences (India)
M D Sharma
2007-12-01
The propagation of plane waves is considered in a general anisotropic elastic medium in the presence of initial stress. The Christoffel equations are solved into a polynomial of degree six. The roots of this polynomial represent the vertical slowness values for the six quasi-waves resulting from the presence of a discontinuity in the medium. Three of these six values are identified with the three quasi-waves traveling in the medium but away from its boundary. Reflection at the free plane surface is studied for partition of energy among the three reflected waves. For post-critical incidence, the reflected waves are inhomogeneous (evanescent) waves. Numerical examples are considered to exhibit the effects of initial stress on the phase direction, attenuation and reflection coefficients of the reflected waves. The phase velocities and energy shares of the reflected waves change significantly with initial stress as well as anisotropic symmetry. The presence of initial stress, however, has a negligible effect on the phase directions of reflected waves.
Anisotropic non-gaussianity from rotational symmetry breaking excited initial states
Energy Technology Data Exchange (ETDEWEB)
Ashoorioon, Amjad [INFN - Sezione di Bologna, IS FLAG,viale B. Pichat 6/2, I-40127 Bologna (Italy); Casadio, Roberto [INFN - Sezione di Bologna, IS FLAG,viale B. Pichat 6/2, I-40127 Bologna (Italy); Dipartimento di Fisica e Astronomia, Alma Mater Università di Bologna,via Irnerio 46, 40126 Bologna (Italy); Koivisto, Tomi [Nordita, KTH Royal Institute of Technology and Stockholm University,Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)
2016-12-01
If the initial quantum state of the primordial perturbations broke rotational invariance, that would be seen as a statistical anisotropy in the angular correlations of the cosmic microwave background radiation (CMBR) temperature fluctuations. This can be described by a general parameterisation of the initial conditions that takes into account the possible direction-dependence of both the amplitude and the phase of particle creation during inflation. The leading effect in the CMBR two-point function is typically a quadrupole modulation, whose coefficient is analytically constrained here to be |B|≲0.06. The CMBR three-point function then acquires enhanced non-gaussianity, especially for the local configurations. In the large occupation number limit, a distinctive prediction is a modulation of the non-gaussianity around a mean value depending on the angle that short and long wavelength modes make with the preferred direction. The maximal variations with respect to the mean value occur for the configurations which are coplanar with the preferred direction and the amplitude of the non-gaussianity increases (decreases) for the short wavelength modes aligned with (perpendicular to) the preferred direction. For a high scale model of inflation with maximally pumped up isotropic occupation and ϵ≃0.01 the difference between these two configurations is about 0.27, which could be detectable in the future. For purely anisotropic particle creation, the non-Gaussianity can be larger and its anisotropic feature very sharp. The non-gaussianity can then reach f{sub NL}∼30 in the preferred direction while disappearing from the correlations in the orthogonal plane.
Anisotropic non-gaussianity from rotational symmetry breaking excited initial states
Ashoorioon, Amjad; Casadio, Roberto; Koivisto, Tomi
2016-12-01
If the initial quantum state of the primordial perturbations broke rotational invariance, that would be seen as a statistical anisotropy in the angular correlations of the cosmic microwave background radiation (CMBR) temperature fluctuations. This can be described by a general parameterisation of the initial conditions that takes into account the possible direction-dependence of both the amplitude and the phase of particle creation during inflation. The leading effect in the CMBR two-point function is typically a quadrupole modulation, whose coefficient is analytically constrained here to be |B| lesssim 0.06. The CMBR three-point function then acquires enhanced non-gaussianity, especially for the local configurations. In the large occupation number limit, a distinctive prediction is a modulation of the non-gaussianity around a mean value depending on the angle that short and long wavelength modes make with the preferred direction. The maximal variations with respect to the mean value occur for the configurations which are coplanar with the preferred direction and the amplitude of the non-gaussianity increases (decreases) for the short wavelength modes aligned with (perpendicular to) the preferred direction. For a high scale model of inflation with maximally pumped up isotropic occupation and epsilonsimeq 0.01 the difference between these two configurations is about 0.27, which could be detectable in the future. For purely anisotropic particle creation, the non-Gaussianity can be larger and its anisotropic feature very sharp. The non-gaussianity can then reach 0fNL ~ 3 in the preferred direction while disappearing from the correlations in the orthogonal plane.
Caspase-2 is an initiator caspase responsible for pore-forming toxin-mediated apoptosis.
Imre, Gergely; Heering, Jan; Takeda, Armelle-Natsuo; Husmann, Matthias; Thiede, Bernd; zu Heringdorf, Dagmar Meyer; Green, Douglas R; van der Goot, F Gisou; Sinha, Bhanu; Dötsch, Volker; Rajalingam, Krishnaraj
2012-05-30
Bacterial pathogens modulate host cell apoptosis to establish a successful infection. Pore-forming toxins (PFTs) secreted by pathogenic bacteria are major virulence factors and have been shown to induce various forms of cell death in infected cells. Here we demonstrate that the highly conserved caspase-2 is required for PFT-mediated apoptosis. Despite being the second mammalian caspase to be identified, the role of caspase-2 during apoptosis remains enigmatic. We show that caspase-2 functions as an initiator caspase during Staphylococcus aureus α-toxin- and Aeromonas aerolysin-mediated apoptosis in epithelial cells. Downregulation of caspase-2 leads to a strong inhibition of PFT-mediated apoptosis. Activation of caspase-2 is PIDDosome-independent, and endogenous caspase-2 is recruited to a high-molecular-weight complex in α-toxin-treated cells. Interestingly, prevention of PFT-induced potassium efflux inhibits the formation of caspase-2 complex, leading to its inactivation, thus resisting apoptosis. These results revealed a thus far unknown, obligatory role for caspase-2 as an initiator caspase during PFT-mediated apoptosis.
SfDronc, an initiator caspase involved in apoptosis in the fall armyworm Spodoptera frugiperda.
Huang, Ning; Civciristov, Srgjan; Hawkins, Christine J; Clem, Rollie J
2013-05-01
Initiator caspases are the first caspases that are activated following an apoptotic stimulus, and are responsible for cleaving and activating downstream effector caspases, which directly cause apoptosis. We have cloned a cDNA encoding an ortholog of the initiator caspase Dronc in the lepidopteran insect Spodoptera frugiperda. The SfDronc cDNA encodes a predicted protein of 447 amino acids with a molecular weight of 51 kDa. Overexpression of SfDronc induced apoptosis in Sf9 cells, while partial silencing of SfDronc expression in Sf9 cells reduced apoptosis induced by baculovirus infection or by treatment with UV or actinomycin D. Recombinant SfDronc exhibited several expected biochemical characteristics of an apoptotic initiator caspase: 1) SfDronc efficiently cleaved synthetic initiator caspase substrates, but had very little activity against effector caspase substrates; 2) mutation of a predicted cleavage site at position D340 blocked autoprocessing of recombinant SfDronc and reduced enzyme activity by approximately 10-fold; 3) SfDronc cleaved the effector caspase Sf-caspase-1 at the expected cleavage site, resulting in Sf-caspase-1 activation; and 4) SfDronc was strongly inhibited by the baculovirus caspase inhibitor SpliP49, but not by the related protein AcP35. These results indicate that SfDronc is an initiator caspase involved in caspase-dependent apoptosis in S. frugiperda, and as such is likely to be responsible for the initiator caspase activity in S. frugiperda cells known as Sf-caspase-X.
Apoptosis initiated by carbon tetrachloride in mitochondria of rat primary cultured hepatocytes
Institute of Scientific and Technical Information of China (English)
Yan CAI; Li-kun GONG; Xin-ming QI; Xiang-hong LI; Jin REN
2005-01-01
Aim: To investigate the mitochondria-initiated apoptosis pathway involved in Carbon tetrachloride (CCl4) hepatotoxicity in vitro. Methods: Several cytotoxicity endpoints, including WST-8 metabolism, lactate dehydrogenase leakage and morphological changes, were examined. The 5,5'-dithio-bis(2-nitrobenzoic acid)reaction was used to measure reduced glutathione level, and the malondialdehyde level was determined using the thiobarbituric acid assay. The release of cytochrome c and Bcl-XL was detected by Western blot. Caspase-3 activity was measured using the fiuorogenic substrate Ac-DEVD-AMC. DNA fragmentation was used to evaluate cell apoptosis. Results: A time- and dose-dependent decrease in cellular glutathione content was observed, along with a concomitant increase in malondialdehyde levels following the application of CC14. Caspase 3 activity was stimulated at all doses of CCl4, with the most significant activation at 3 mmol/L.Cytochrome c was released obviously after CC14 treatment. A time-dependent decrease in Bcl-XL expression was observed. DNA fragmentation results revealed apoptosis and necrosis following CC14 treatment. Conclusion: Oxidative damage is one of the essential mechanisms of CC14 hepatotoxicity, which triggers apoptosis via the mitochondria-initiated pathway.
Institute of Scientific and Technical Information of China (English)
JIN Hua-liang; DONG Jing-cheng
2011-01-01
Idiopathic pulmonary fibrosis (IPF) is a progressive and often fatal form of interstitial lung disease.Despite extensive efforts in research during recent years,the mechanisms of the disease remain poorly understood.Evidence of an inflammatory mechanism,both supportive and contrary,is briefly reviewed in this paper.However,growing evidence has indicated that the apoptosis of alveolar epithelial cells (AECs) may be the early driving force of progression,with subsequent disrupted integrity of the alveolar-capillary basement membrane leading to an abnormal wound healing pathway.Thus,this paper will focus on outlining a process of pathogenesis of IPF from initial apoptosis of AECs to end lung remodeling.
Anisotropic non-Gaussianity from Rotational Symmetry Breaking Excited Initial States
Ashoorioon, Amjad; Koivisto, Tomi
2016-01-01
If the initial quantum state of the primordial perturbations broke rotational invariance, that would be seen as a statistical anisotropy in the angular correlations of the cosmic microwave background radiation (CMBR) temperature fluctuations. This can be described by a general parameterisation of the initial conditions that takes into account the possible direction-dependence of both the amplitude and the phase of particle creation during inflation. The leading effect in the CMBR two-point function is typically a quadrupole modulation, whose coefficient is analytically constrained here to be $|B| \\lesssim 0.06$. The CMBR three-point function then acquires enhanced non-gaussianity, especially for the local configurations. In the large occupation number limit, a distinctive prediction is a modulation of the non-gaussianity around a mean value depending on the angle that short and long wavelength modes make with the preferred direction. The maximal variations with respect to the mean value occur for the configur...
MohanKumar, Krishnan; Killingsworth, Cheryl R; McIlwain, R Britt; Timpa, Joseph G; Jagadeeswaran, Ramasamy; Namachivayam, Kopperuncholan; Kurundkar, Ashish R; Kelly, David R; Garzon, Steven A; Maheshwari, Akhil
2014-02-01
Neonates and young infants exposed to extracorporeal circulation during extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass are at risk of developing a systemic inflammatory response syndrome with multi-organ dysfunction. We used a piglet model of ECMO to investigate the hypothesis that epithelial apoptosis is an early event that precedes villous damage during ECMO-related bowel injury. Healthy 3-week-old piglets were subjected to ECMO for up to 8 h. Epithelial apoptosis was measured in histopathological analysis, nuclear imaging, and terminal deoxynucleotidyl transferase dUTP nick end labeling. Plasma intestinal fatty acid-binding protein (I-FABP) levels were measured by enzyme immunoassay. Intestinal mast cells were isolated by fluorescence-assisted cell sorting. Cleaved caspase-8, caspase-9, phospho-p38 MAPK, and fas ligand expression were investigated by immunohistochemistry, western blots, and reverse transcriptase-quantitative PCR. Piglet ECMO was associated with increased gut epithelial apoptosis. Extensive apoptotic changes were noted on villus tips and in scattered crypt cells after 2 h of ECMO. After 8 h, the villi were denuded and apoptotic changes were evident in a majority of crypt cells. Increased circulating I-FABP levels, a marker of gut epithelial injury, showed that epithelial injury occurred during ECMO. We detected increased cleaved caspase-8, but not cleaved caspase-9, in epithelial cells indicating that the extrinsic apoptotic pathway was active. ECMO was associated with increased fas ligand expression in intestinal mast cells, which was induced through activation of the p38 mitogen-activated protein kinase. We conclude that epithelial apoptosis is an early event that initiates gut mucosal injury in a piglet model of ECMO.
Barrow, John D
2015-01-01
We study the behaviour of Bianchi class A universes containing an ultra-stiff isotropic ghost field and a fluid with anisotropic pressures which is also ultra-stiff on the average. This allows us to investigate whether cyclic universe scenarios, like the ekpyrotic model, do indeed lead to isotropisation on approach to a singularity (or bounce) in the presence of dominant ultra-stiff pressure anisotropies. We specialise to consider the closed Bianchi type IX universe and show that when the anisotropic pressures are stiffer on average than any isotropic ultra-stiff fluid then, if they dominate on approach to the singularity, it will be anisotropic. We include an isotropic ultra-stiff ghost fluid with negative energy density in order to create a cosmological bounce at finite volume in the absence of the anisotropic fluid. When the dominant anisotropic fluid is present it leads to an anisotropic cosmological singularity rather than an isotropic bounce. The inclusion of anisotropic stresses generated by collisionl...
Energy Technology Data Exchange (ETDEWEB)
Yamaguchi, Akinobu, E-mail: yamaguti@lasti.u-hyogo.ac.jp, E-mail: utsumi@lasti.u-hyogo.ac.jp; Kido, Hideki; Utsumi, Yuichi, E-mail: yamaguti@lasti.u-hyogo.ac.jp, E-mail: utsumi@lasti.u-hyogo.ac.jp [University of Hyogo, 3-1-2 Kouto, Kamigori, Ako, Hyogo 678-1205 (Japan); Ukita, Yoshiaki [University of Yamanashi, 4-3-11 Takeda, Kohfu, Yamanashi 400-8511 (Japan); Kishihara, Mitsuyoshi [Okayama Prefectural University, 111 Kuboki, Sousha, Okayama 719-1197 (Japan)
2016-02-01
We developed a process for micromachining polytetrafluoroethylene (PTFE): anisotropic pyrochemical microetching induced by synchrotron X-ray irradiation. X-ray irradiation was performed at room temperature. Upon heating, the irradiated PTFE substrates exhibited high-precision features. Both the X-ray diffraction peak and Raman signal from the irradiated areas of the substrate decreased with increasing irradiation dose. The etching mechanism is speculated as follows: X-ray irradiation caused chain scission, which decreased the number-average degree of polymerization. The melting temperature of irradiated PTFE decreased as the polymer chain length decreased, enabling the treated regions to melt at a lower temperature. The anisotropic pyrochemical etching process enabled the fabrication of PTFE microstructures with higher precision than simultaneously heating and irradiating the sample.
Analysis of Residual DSBs in Ataxia-Telangiectasia Lymphoblast Cells Initiating Apoptosis
Directory of Open Access Journals (Sweden)
Teresa Anglada
2016-01-01
Full Text Available In order to examine the relationship between accumulation of residual DNA double-strand breaks (DSBs and cell death, we have used a control and an ATM (Ataxia-Telangiectasia Mutated defective cell line, as Ataxia-Telangiectasia (AT cells tend to accumulate residual DSBs at long times after damage infliction. After irradiation, AT cells showed checkpoint impairment and a fraction of cells displayed an abnormal centrosome number and tetraploid DNA content, and this fraction increased along with apoptosis rates. At all times analyzed, AT cells displayed a significantly higher rate of radiation-induced apoptosis than normal cells. Besides apoptosis, 70–85% of the AT viable cells (TUNEL-negative carried ≥10 γH2AX foci/cell, while only 12–27% of normal cells did. The fraction of AT and normal cells undergoing early and late apoptosis were isolated by flow cytometry and residual DSBs were concretely scored in these populations. Half of the γH2AX-positive AT cells undergoing early apoptosis carried ≥10 γH2AX foci/cell and this fraction increased to 75% in late apoptosis. The results suggest that retention of DNA damage-induced γH2AX foci is an indicative of lethal DNA damage, as cells undergoing apoptosis are those accumulating more DSBs. Scoring of residual γH2AX foci might function as a predictive tool to assess radiation-induced apoptosis.
ER stress does not cause upregulation and activation of caspase-2 to initiate apoptosis.
Sandow, J J; Dorstyn, L; O'Reilly, L A; Tailler, M; Kumar, S; Strasser, A; Ekert, P G
2014-03-01
A recent report claimed that endoplasmic reticulum (ER) stress activates the ER trans-membrane receptor IRE1α, leading to increased caspase-2 levels via degradation of microRNAs, and consequently induction of apoptosis. This observation casts caspase-2 into a central role in the apoptosis triggered by ER stress. We have used multiple cell types from caspase-2-deficient mice to test this hypothesis but failed to find significant impact of loss of caspase-2 on ER-stress-induced apoptosis. Moreover, we did not observe increased expression of caspase-2 protein in response to ER stress. Our data strongly argue against a critical role for caspase-2 in ER-stress-induced apoptosis.
Saha, Anup; Kundu, Santimoy; Gupta, Shishir; Vaishnav, Pramod Kumar
2016-06-01
The present paper is concerned with the propagation of torsional surface waves in an initially stressed anisotropic porous layer sandwiched between homogeneous and non-homogeneous half-space. We assume the quadratic inhomogeneity in rigidity and density in the lower half-space and irregularity is taken in the form of rectangle at the interface separating the layer from the lower half-space. The dispersion equation for torsional waves has been obtained in a closed form. Velocity equation is also obtained in the absence of irregularity. The study reveals that the presence of irregularity, initial stress, porosity, inhomogeneity and anisotropy factor in the dispersion equation approves the significant effect of these parameters in the propagation of torsional waves in porous medium. It has also been observed that for a uniform media, the velocity equation reduces to the classical result of Love wave.
Sendler, Matthias; Maertin, Sandrina; John, Daniel; Persike, Maria; Weiss, F Ulrich; Krüger, Burkhard; Wartmann, Thomas; Wagh, Preshit; Halangk, Walter; Schaschke, Norbert; Mayerle, Julia; Lerch, Markus M
2016-07-08
Pancreatitis is associated with premature activation of digestive proteases in the pancreas. The lysosomal hydrolase cathepsin B (CTSB) is a known activator of trypsinogen, and its deletion reduces disease severity in experimental pancreatitis. Here we studied the activation mechanism and subcellular compartment in which CTSB regulates protease activation and cellular injury. Cholecystokinin (CCK) increased the activity of CTSB, cathepsin L, trypsin, chymotrypsin, and caspase 3 in vivo and in vitro and induced redistribution of CTSB to a secretory vesicle-enriched fraction. Neither CTSB protein nor activity redistributed to the cytosol, where the CTSB inhibitors cystatin-B/C were abundantly present. Deletion of CTSB reduced and deletion of cathepsin L increased intracellular trypsin activation. CTSB deletion also abolished CCK-induced caspase 3 activation, apoptosis-inducing factor, as well as X-linked inhibitor of apoptosis protein degradation, but these depended on trypsinogen activation via CTSB. Raising the vesicular pH, but not trypsin inhibition, reduced CTSB activity. Trypsin inhibition did not affect apoptosis in hepatocytes. Deletion of CTSB affected apoptotic but not necrotic acinar cell death. In summary, CTSB in pancreatitis undergoes activation in a secretory, vesicular, and acidic compartment where it activates trypsinogen. Its deletion or inhibition regulates acinar cell apoptosis but not necrosis in two models of pancreatitis. Caspase 3-mediated apoptosis depends on intravesicular trypsinogen activation induced by CTSB, not CTSB activity directly, and this mechanism is pancreas-specific.
Caspase-2 is an initiator caspase responsible for pore-forming toxin-mediated apoptosis
Imre, Gergely; Heering, Jan; Takeda, Armelle-Natsuo; Husmann, Matthias; Thiede, Bernd; Heringdorf, Dagmar Meyer Zu; Green, Douglas R.; van der Goot, F. Gisou; Sinha, Bhanu; Doetsch, Volker; Rajalingam, Krishnaraj
2012-01-01
Bacterial pathogens modulate host cell apoptosis to establish a successful infection. Pore-forming toxins (PFTs) secreted by pathogenic bacteria are major virulence factors and have been shown to induce various forms of cell death in infected cells. Here we demonstrate that the highly conserved casp
Initial study on apoptosis in HepG-2 Human heptocarcinoma cell line by CSS
Institute of Scientific and Technical Information of China (English)
YU Lei; CUI Rong-tian; MO Ke; WANG Wei; JI Yu-bin; ZOU Xiang
2008-01-01
Objective To discuss on mechanism of the killing and apoptosis inducing effect induced by total alkaloid in the CSS(Capparis spinosa L. saponin, CSS)on human hepatocarcinoma cell Line HepG-2. Methods The killing effect of the CSS on human hepatocarcinoma cell Line HepG-2 was observed by MTT method. Morphological observation of the HepG-2 cells was completed by fluorescence microscope. This test was signed to observe the changes of the cell cycle of HepG-2 cells affected by the CSS by PI single-staining, and to observe if there were typical apoptosis peaks. The apoptosis inducing effect and changing of mitochondria membrane potential of the CSS on the HepG-2 cells were studied by flow cytometry. The effect of intraceUular Ca2+ level of CSS on the HepG-2 cells was measured by laser confocal microscope. Results CSS has growth inhibiting on the HepG-2 and seems to be enhanced with the increasing concentration of CSS, and its IC50 value was 46.16 μg·mL-1. The HepG-2 cells are characteristic apoptosis morphologic changed, and the apoptosis percentage is increased to 66.652 % in the 50 μg·mL-1 dosage group. The cells cycle has been changed obviously that the progresses of cells cycle of G1 period and G2 period in high dosage group have been blocked, and the cellular proportion in G2 period is decreased by the function of CSS for 24 h. The mitochondria membrane potential of HepG-2 cells induced by CSS is decreased in various degrees. In addition, the intracellular Ca2+ level is increased by the function of CSS in the middle and high dose groups. Conclusions The CSS has obviously killing and apoptosis inducing effect on human hepatoearcinoma cell Line HepG-2 by the mechanism of decreasing the mitochondria membrane potential and increasing the intracellular Ca2+ level.
Florkowski, W.; Maj, R.
The recently introduced approach describing coupled quark and gluon anisotropic fluids is generalized to include explicitly the transitions between quarks and gluons. We study the effects of such processes on the thermalization rate of anisotropic systems. We find that the quark-gluon transitions may enhance the overall thermalization rate in the cases where the initial momentum anisotropies correspond to mixed oblate-prolate or prolate configurations. On the other hand, no effect on the thermalization rate is found in the case of oblate configurations. The observed regularities are connected with the late-time behavior of the analyzed systems which is described either by the exponential decay or the power law.
Florkowski, Wojciech
2013-01-01
The recently introduced approach describing coupled quark and gluon anisotropic fluids is generalized to include explicitly the transitions between quarks and gluons. We study the effects of such processes on the thermalization rate of anisotropic systems. We find that the quark-gluon transitions may enhance the overall thermalization rate in the cases where the initial momentum anisotropies correspond to mixed oblate-prolate or prolate configurations. On the other hand, no effect on the thermalization rate is found in the case of oblate configurations. The observed regularities are connected with the late-time behavior of the analyzed systems which is described either by the exponential decay or the power law.
DEFF Research Database (Denmark)
Henríquez-Hernández, Luis Alberto; Pinar, Beatriz; Carmona-Vigo, Ruth
2013-01-01
suffering from locally advanced breast cancer and treated with high-dose hyperfractionated radiotherapy were recruited. Initial DNA damage was measured by pulsed-field gel electrophoresis and radiation-induced apoptosis was measured by flow cytometry. Gene expression was assessed by DNA microarray. RESULTS...
Directory of Open Access Journals (Sweden)
Khoshtinat Nikkhoi
2016-09-01
Full Text Available Background Cancerous cells proliferate as fast as possible without a proper surveillance system. This rapid cell division leads to enormous mutation rates, which help a tumor establish. Objectives This study evaluated the potential of inducing apoptosis using Noxa and Puma in a hepatocarcinoma cell line. Methods The current study generated two recombinant lentiviruses, pLEX-GCN and pLEX-GCP, bearing Noxa and Puma, respectively. Transduction of both genes to hepatocarcinoma (HepG2 was verified using fluorescent microscopic analysis, western blotting, and quantitative real-time polymerase chain reaction (PCR. To evaluate the potential of Noxa and Puma to initiate apoptosis, a caspase-9 real-time, MTT assay, and a 4’, 6-diamidino-2-phenylindole (DAPI reagent were performed to stain apoptotic cells. Results The data verified successful transduction to HepG2 and HEK293T. Higher relative expression of Noxa and Puma rather than the untransduced cell line showed these genes are expressed more in HepG2 in comparison to HEK293T. The results of the real-time PCR, MTT assay, and DAPI reagent illustrated that higher cells initiated apoptosis following Puma transduction rather than Noxa. Conclusions In this approach, the suicide gene was transferred to transformed cells and ignited apoptosis to exterminate them. Puma is a more potent killer gene and has higher capabilities to start intrinsic apoptosis pathway.
Li, Yun; Mei, Zhu; Liu, Shuiqiao; Wang, Tong; Li, Hui; Li, Xiao-Xiao; Han, Song; Yang, Yutao; Li, Junfa; Xu, Zhi-Qing David
2017-01-01
Galanin (GAL) plays key role in many pathophysiological processes, but its role in ischemic stroke remains unclear. Here, the models of 1 h middle cerebral artery occlusion (MCAO)/1-7 d reperfusion (R)-induced ischemic stroke and in vitro cell ischemia of 1 h oxygen-glucose deprivation (OGD)/24 h reoxygenation in primary cultured cortical neurons were used to explore GAL’s effects and its underlying mechanisms. The results showed significant increases of GAL protein levels in the peri-infarct region (P) and infarct core (I) within 48 h R of MCAO mice (p<0.001). The RT-qPCR results also demonstrated significant increases of GAL mRNA during 24-48 h R (p<0.001), and GAL receptors GalR1-2 (but not 3) mRNA levels in the P region at 24 h R of MCAO mice (p<0.001). Furthermore, the significant decrease of infarct volume (p<0.05) and improved neurological outcome (p<0.001-0.05) were observed in MCAO mice following 1 h pre- or 6 h post-treatment of GAL during 1-7 d reperfusion. GalR1 was confirmed as the receptor responsible for GAL-induced neuroprotection by using GalR2/3 agonist AR-M1896 and Lentivirus-based RNAi knockdown of GalR1. GAL treatment inhibited Caspase-3 activation through the upstream initiators Capsases-8/-12 (not Caspase-9) in both P region and OGD-treated cortical neurons. Meanwhile, GAL’s neuroprotective effect was not observed in cortical neurons from conventional protein kinase C (cPKC) γ knockout mice. These results suggested that exogenous GAL protects the brain from ischemic injury by inhibiting Capsase-8/12-initiated apoptosis, possibly mediated by GalR1 via the cPKCγ signaling pathway. PMID:28203483
Directory of Open Access Journals (Sweden)
Chuturgoon Anil A
2011-11-01
Full Text Available Abstract Background Rheumatoid arthritis (RA is a chronic autoimmune disease, which causes synovial damage. Persistence of lymphocyte infiltrates in the rheumatoid synovium has been attributed to abnormal apoptosis. While not comprehensively investigated, perturbations in peripheral blood lymphocyte (PBL apoptosis may also be involved in perpetuation of autoimmune processes in RA. Methods We investigated total, CD4+ and CD19+ PBL apoptosis in our study cohort by monitoring the translocation of phosphatidylserine using the Annexin-V assay. To examine the role of death receptor mediated apoptosis as well as activation-induced-cell-death (AICD, PBLs were labeled with CD95/Fas and CD69 markers and enumerated by flow cytometry. Proteolytic activity of initiator and executioner caspases was determined by luminometry. DNA fragmentation assays were used to examine whether apoptotic signals were transduced to the nucleus. Quantitative PCR arrays were used to investigate apoptotic pathways associated with RA-PBLs. Since heat-shock-protein-70 (HSP70 is an inducible protein which modulates apoptotic signals, we determined HSP70 levels by intra-cellular flow cytometry and western blots. Results The RA-PBLs showed signs of elevated apoptosis whilst in circulation. These include increases in the loss of plasma membrane asymmetry, indicated by increased externalization of phosphatidylserine (especially in B-lymphocytes. RA-PBLs showed a bias to CD95/Fas mediated apoptotic pathways, but low levels of the CD69 marker suggested that this was not associated with immune activation. Although downstream markers of apoptosis such as caspase-3/7 activity, were increased, no DNA fragmentation was observed in RA-PBLs. Interestingly, elevated levels of apoptosis did not correlate with absolute lymphocyte counts in RA patients. Levels of HSP70 were highly elevated in RA-PBLs compared to controls. Conclusion The results suggest that while apoptosis may be initiated in RA
PHENOMENOLOGICAL DAMAGE MODELS OF ANISOTROPIC STRUCTURAL MATERIALS
Bobyr, M.; Khalimon, O.; Bondarets, O.
2015-01-01
Damage in metals is mainly the process of the initiation and growth of voids. A formulation for anisotropic damage is established in the framework of the principle of strain equivalence, principle of increment complementary energy equivalence and principle of elastic energy equivalence. This paper presents the development of an anisotropic damage theory. This work is focused on the development of evolution anisotropic damage models which is based on a Young’s modulus/Poisson’s ratio change of...
Inhomogeneous anisotropic cosmology
Kleban, Matthew; Senatore, Leonardo
2016-10-01
In homogeneous and isotropic Friedmann-Robertson-Walker cosmology, the topology of the universe determines its ultimate fate. If the Weak Energy Condition is satisfied, open and flat universes must expand forever, while closed cosmologies can recollapse to a Big Crunch. A similar statement holds for homogeneous but anisotropic (Bianchi) universes. Here, we prove that arbitrarily inhomogeneous and anisotropic cosmologies with ``flat'' (including toroidal) and ``open'' (including compact hyperbolic) spatial topology that are initially expanding must continue to expand forever at least in some region at a rate bounded from below by a positive number, despite the presence of arbitrarily large density fluctuations and/or the formation of black holes. Because the set of 3-manifold topologies is countable, a single integer determines the ultimate fate of the universe, and, in a specific sense, most 3-manifolds are ``flat'' or ``open''. Our result has important implications for inflation: if there is a positive cosmological constant (or suitable inflationary potential) and initial conditions for the inflaton, cosmologies with ``flat'' or ``open'' topology must expand forever in some region at least as fast as de Sitter space, and are therefore very likely to begin inflationary expansion eventually, regardless of the scale of the inflationary energy or the spectrum and amplitude of initial inhomogeneities and gravitational waves. Our result is also significant for numerical general relativity, which often makes use of periodic (toroidal) boundary conditions.
Inhomogeneous anisotropic cosmology
Energy Technology Data Exchange (ETDEWEB)
Kleban, Matthew [Center for Cosmology and Particle Physics, New York University,4 Washington Place, New York, NY 10003 (United States); Senatore, Leonardo [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,382 Via Pueblo Mall, Stanford, CA 94306 (United States); Kavli Institute for Particle Astrophysics and Cosmology, Stanford University and SLAC,2575 Sand Hill Road, M/S 29, Menlo Park, CA 94025 (United States)
2016-10-12
In homogeneous and isotropic Friedmann-Robertson-Walker cosmology, the topology of the universe determines its ultimate fate. If the Weak Energy Condition is satisfied, open and flat universes must expand forever, while closed cosmologies can recollapse to a Big Crunch. A similar statement holds for homogeneous but anisotropic (Bianchi) universes. Here, we prove that arbitrarily inhomogeneous and anisotropic cosmologies with “flat” (including toroidal) and “open” (including compact hyperbolic) spatial topology that are initially expanding must continue to expand forever at least in some region at a rate bounded from below by a positive number, despite the presence of arbitrarily large density fluctuations and/or the formation of black holes. Because the set of 3-manifold topologies is countable, a single integer determines the ultimate fate of the universe, and, in a specific sense, most 3-manifolds are “flat” or “open”. Our result has important implications for inflation: if there is a positive cosmological constant (or suitable inflationary potential) and initial conditions for the inflaton, cosmologies with “flat” or “open” topology must expand forever in some region at least as fast as de Sitter space, and are therefore very likely to begin inflationary expansion eventually, regardless of the scale of the inflationary energy or the spectrum and amplitude of initial inhomogeneities and gravitational waves. Our result is also significant for numerical general relativity, which often makes use of periodic (toroidal) boundary conditions.
Ita, Eyo
2009-01-01
In this paper we illustrate the dynamics of the Chang--Soo/CDJ variables in the description of vacuum GR in anisotropic minisuperspace, uncovering a new class of general solutions in both the degenerate and the nondegenerate sectors. One result of these new variables is the existence of an unbridgable gap between these sectors. The gravitational dynamics self-consistently hold down to arbitrarily small times, implying a semiclassical-quantum correspondence as well as an elimination of the big bang singularity in the nondegenerate sector. We also present an algorithm for constructing general solutions for the spacetimes labelling a general quantum state in these variables.
Wang, La; Song, Juan; Bao, Xi-Yan; Chen, Peng; Yi, Hua-Shan; Pan, Min-Hui; Lu, Cheng
2016-10-15
The identification and analysis of the caspases is essential to research into apoptosis in lepidoptera insects. The domesticated silkworm, Bombyx mori, is the model system for lepidopterans. In this study, we cloned and characterized a B. mori Dredd gene, BmDredd, the proposed insect homologue of human caspase-8, which encoded a polypeptide of 543 amino acids. BmDredd possesses a long N-terminal prodomain, a p20 domain, and a p10 domain. When transiently expressed in Escherichia coli cells, BmDredd underwent spontaneous cleavage and exhibited high proteolytic activity for caspase-8 substrate but relatively low for caspase-3 or -9 substrate. In addition, BmDredd induced apoptosis when transiently expressed in BmN-SWU1 cells, an ovarian cell line of B. mori. Moreover, after the treatment of Emodin, a novel apoptosis inducer, endogenous BmDredd expression level, the caspase-8 activity and the apoptotic rate increased notably in BmN-SWU1 cells. When BmDredd was subjected to interference in BmN-SWU1 cells and Emodin treatment, BmDredd expression levels decreased and the apoptotic rate also decreased significantly. These results suggest BmDredd is the homologue of human caspase-8 and plays a role in Emodin-induced apoptosis in BmN-SWU1 cells of B. mori.
Directory of Open Access Journals (Sweden)
Harald F. Krug
2012-01-01
Full Text Available Tributyltin (TBT is one of the most toxic compounds produced by man and distributed in the environment. A multitude of toxic activities have been described, for example, immunotoxic, neurotoxic, and endocrine disruptive effects. Moreover, it has been shown for many cell types that they undergo apoptosis after treatment with TBT and the cell death of immune cells could be the molecular background of its immunotoxic effect. As low as 200 nM up to 1 μM of TBT induces all signs of apoptosis in Jurkat T cells within 1 to 24 hrs of treatment. When compared to Fas-ligand control stimulation, the same sequence of events occurs: membrane blebbing, phosphatidylserine externalisation, the activation of the “death-inducing signalling complex,” and the following sequence of cleavage processes. In genetically modified caspase-8-deficient Jurkat cells, the apoptotic effects are only slightly reduced, whereas, in FADD-negative Jurkat cells, the TBT effect is significantly diminished. We could show that caspase-10 is recruited by the TRAIL-R2 receptor and apoptosis is totally prevented when caspase-10 is specifically inhibited in all three cell lines.
Nakayama, Yohei; Matsui, Sari; Noda, Keisuke; Yamazaki, Mizuho; Iwai, Yasunobu; Matsumura, Hiroyoshi; Izawa, Takashi; Tanaka, Eiji; Ganss, Bernhard; Ogata, Yorimasa
2016-10-01
Amelotin (AMTN) is expressed and secreted by ameloblasts in the maturation stage of amelogenesis and persist with low levels in the junctional epithelium (JE) of erupted teeth. The purpose of this study is to investigate the transcriptional regulation of the AMTN gene by transforming growth factor beta1 (TGFβ1) in gingival epithelial (GE1) cells in the apoptosis phase. Apoptosis was evaluated by the fragmentation of chromosomal DNA and TUNEL staining. A real-time PCR was carried out to examine the AMTN mRNA levels induced by TGFβ1 and Smad3 overexpression. Transient transfection analyses were completed using the various lengths of mouse AMTN gene promoter constructs with or without TGFβ1. Chromatin immunoprecipitation (ChIP) assays were performed to investigate the Smad3 bindings to the AMTN gene promoter by TGFβ1. TGFβ1-induced apoptosis in GE1 cells were detected at 24 and 48 h by DNA fragmentation and TUNEL staining. AMTN mRNA levels increased at 6 h and reached maximum at 24 h in GE1 cells. Luciferase activities of the mouse AMTN gene promoter constructs were induced by TGFβ1. The results of the ChIP assays showed that there was an increase in Smad3 binding to Smad-binding element (SBE)#1 and SBE#2 after stimulation by TGFβ1. Immunohistochemical localization of AMTN was detected in the JE, and the AMTN protein levels in Smad3-deficient mice were decreased compared with wild-type mice. AMTN mRNA levels were induced at the initiation of apoptosis by TGFβ1, which mediated through the Smad3 bindings to SBEs in the mouse AMTN gene promoter.
Indian Academy of Sciences (India)
Anup Saha; Santimoy Kundu; Shishir Gupta; Pramod Kumar Vaishnav
2016-06-01
The present paper is concerned with the propagation of torsional surface waves in an initially stressedanisotropic porous layer sandwiched between homogeneous and non-homogeneous half-space. We assumethe quadratic inhomogeneity in rigidity and density in the lower half-space and irregularity is taken inthe form of rectangle at the interface separating the layer from the lower half-space. The dispersionequation for torsional waves has been obtained in a closed form. Velocity equation is also obtained inthe absence of irregularity. The study reveals that the presence of irregularity, initial stress, porosity,inhomogeneity and anisotropy factor in the dispersion equation approves the significant effect of theseparameters in the propagation of torsional waves in porous medium. It has also been observed that fora uniform media, the velocity equation reduces to the classical result of Love wave.
Recent progress in anisotropic hydrodynamics
Strickland, Michael
2016-01-01
The quark-gluon plasma created in a relativistic heavy-ion collisions possesses a sizable pressure anisotropy in the local rest frame at very early times after the initial nuclear impact and this anisotropy only slowly relaxes as the system evolves. In a kinetic theory picture, this translates into the existence of sizable momentum-space anisotropies in the underlying partonic distribution functions, . In such cases, it is better to reorganize the hydrodynamical expansion by taking into account momentum-space anisotropies at leading-order in the expansion instead of as a perturbative correction to an isotropic distribution. The resulting anisotropic hydrodynamics framework has been shown to more accurately describe the dynamics of rapidly expanding systems such as the quark-gluon plasma. In this proceedings contribution, I review the basic ideas of anisotropic hydrodynamics, recent progress, and present a few preliminary phenomenological predictions for identified particle spectra and elliptic flow.
Fast Anisotropic Gauss Filtering
Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.; Heyden, A.; Sparr, G.; Nielsen, M.; Johansen, P.
2002-01-01
We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction followed by a one dimensional filter in a non-orthogonal direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a computin
Fast Anisotropic Gauss Filters
Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.
2003-01-01
We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a computing perspective. An implementation scheme for normal covolution and f
Energy Technology Data Exchange (ETDEWEB)
Wang, J. [The First Affiliated Hospital, Liaoning Medical University, Jinzhou (China); Key Laboratory of Cardiovascular and Cerebrovascular Drug Research, Liaoning Province, Liaoning Medical University, Jinzhou (China); Lu, M.L.; Dai, H.L.; Zhang, S.P.; Wang, H.X. [Key Laboratory of Cardiovascular and Cerebrovascular Drug Research, Liaoning Province, Liaoning Medical University, Jinzhou (China); Wei, N. [The First Affiliated Hospital, Liaoning Medical University, Jinzhou (China)
2014-12-12
This study investigated the in vitro and in vivo antiproliferative activity of esculetin against hepatocellular carcinoma, and clarified its potential molecular mechanisms. Cell viability was determined by the MTT (tetrazolium) colorimetric assay. In vivo antitumor activity of esculetin was evaluated in a hepatocellular carcinoma mouse model. Seventy-five C57BL/6J mice were implanted with Hepa1-6 cells and randomized into five groups (n=15 each) given daily intraperitoneal injections of vehicle (physiological saline), esculetin (200, 400, or 700 mg·kg{sup -1}·day{sup -1}), or 5-Fu (200 mg·kg{sup -1}·day{sup -1}) for 15 days. Esculetin significantly decreased tumor growth in mice bearing Hepa1-6 cells. Tumor weight was decreased by 20.33, 40.37, and 55.42% with increasing doses of esculetin. Esculetin significantly inhibited proliferation of HCC cells in a concentration- and time-dependent manner and with an IC{sub 50} value of 2.24 mM. It blocked the cell cycle at S phase and induced apoptosis in SMMC-7721 cells with significant elevation of caspase-3 and caspase-9 activity, but did not affect caspase-8 activity. Moreover, esculetin treatment resulted in the collapse of mitochondrial membrane potential in vitro and in vivo accompanied by increased Bax expression and decreased Bcl-2 expression at both transcriptional and translational levels. Thus, esculetin exerted in vitro and in vivo antiproliferative activity in hepatocellular carcinoma, and its mechanisms involved initiation of a mitochondrial-mediated, caspase-dependent apoptosis pathway.
Directory of Open Access Journals (Sweden)
J. Wang
2015-03-01
Full Text Available This study investigated the in vitro and in vivo antiproliferative activity of esculetin against hepatocellular carcinoma, and clarified its potential molecular mechanisms. Cell viability was determined by the MTT (tetrazolium colorimetric assay. In vivo antitumor activity of esculetin was evaluated in a hepatocellular carcinoma mouse model. Seventy-five C57BL/6J mice were implanted with Hepa1-6 cells and randomized into five groups (n=15 each given daily intraperitoneal injections of vehicle (physiological saline, esculetin (200, 400, or 700 mg·kg-1·day-1, or 5-Fu (200 mg·kg-1·day-1 for 15 days. Esculetin significantly decreased tumor growth in mice bearing Hepa1-6 cells. Tumor weight was decreased by 20.33, 40.37, and 55.42% with increasing doses of esculetin. Esculetin significantly inhibited proliferation of HCC cells in a concentration- and time-dependent manner and with an IC50 value of 2.24 mM. It blocked the cell cycle at S phase and induced apoptosis in SMMC-7721 cells with significant elevation of caspase-3 and caspase-9 activity, but did not affect caspase-8 activity. Moreover, esculetin treatment resulted in the collapse of mitochondrial membrane potential in vitro and in vivo accompanied by increased Bax expression and decreased Bcl-2 expression at both transcriptional and translational levels. Thus, esculetin exerted in vitro and in vivo antiproliferative activity in hepatocellular carcinoma, and its mechanisms involved initiation of a mitochondrial-mediated, caspase-dependent apoptosis pathway.
Anisotropic Flow Measurements in ALICE at the Large Hadron Collider
Bilandzic, A.
2012-01-01
Anisotropic ﬂow is one of the observables which is sensitive to the properties of the created hot and dense system in heavy-ion collisions. In noncentral heavy-ion collisions the initial volume of the interacting system is anisotropic in coordinate space. Due to multiple interactions this anisotropy
Comments on inhomogeneous anisotropic cosmology
Kaya, Ali
2016-01-01
Recently a new no-global-recollapse argument is given for some inhomogeneous and anisotropic cosmologies that utilizes surface deformation by the mean curvature flow. In this note we point out a few important issues about the proposed deformations and in particular indicate that in the presence of large spatial variations the mean curvature flow may deform an initially spacelike surface to a surface with null or timelike portions. The time evolution of the spatial scalar curvature that prevents recollapse is determined in normal coordinates, which shows the impact of inhomogeneities explicitly. Our analysis also indicates a possible caveat in numerical solutions that give rise to inflation.
Anisotropic Contrast Optical Microscope
Peev, D; Kananizadeh, N; Wimer, S; Rodenhausen, K B; Herzinger, C M; Kasputis, T; Pfaunmiller, E; Nguyen, A; Korlacki, R; Pannier, A; Li, Y; Schubert, E; Hage, D; Schubert, M
2016-01-01
An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. We demonstrate the anisotropic contrast optical microscope by mea...
Prabhu, Bhoopathy; Sivakumar, Annamalai; Sundaresan, Sivapatham
2016-10-01
Bladder cancer has been shown to resist programmed cell death with altered expression of both pro-apoptotic and anti-apoptotic proteins. To study is to investigate the apoptotic properties of Diindolylmethane (DIM) and Lupeol on N-Butyl-N-(4-hydroxybutyl) Nitrosamine (BBN) initiated and Dimethylarsinic Acid (DMA) promoted urinary bladder cancer. Sixty male Wistar rats were divided into 6 groups. Group I: Control. Group II: Rats were experimentally developed bladder carcinogenesis with BBN and DMA. Group III and IV: DIM and lupeol were administered after BBN treatment for 28 weeks. Group V and VI: DIM and lupeol alone treatment for 36 weeks. All the experimental rats were maintained and euthanized after 36 weeks protocol. Urinary bladder tissues were collected and processed for further investigations. Apoptotis and cell proliferative marker such as Bax, Bcl-2, caspase-3, caspase-9 and PCNA were quantified using immunohistochemical analysis. The Immunohistochemical expression of Bax, Bcl-2, caspase-3, caspase-9 and PCNA were aberrant in BBN + DMA treated tumor group. Administration of DIM and lupeol inhibited the progression of bladder cancer, induced the expression of apoptotic Bax, caspase-3, caspase-9 and inhibited the expression of anti-apoptotic Bcl-2, PCNA in the urinary bladder of rats. Administration of diindolylmethane and lupeol treatment induces apoptosis and cellular proliferation by its anti-carcinogenic properties. From our results DIM and lupeol would be the agent or adjunct for the treatment of bladder carcinogenesis.
ANISOTROPIC PARABOLIC EQUATIONS WITH MEASURE DATA
Institute of Scientific and Technical Information of China (English)
Li Fengquan; Zhao Huixiu
2001-01-01
In this paper, we prove the existence of solutions to anisotropic parabolic equations with right hand side term in the bounded Radon measure M(Q) and the initial condition in M(Ω) or in Lm space (with m "small").
The Kepler Problem with Anisotropic Perturbations
Diacu, Florin; Santoprete, Manuele
2009-01-01
We study a 2-body problem given by the sum of the Newtonian potential and an anisotropic perturbation that is a homogeneous function of degree $-\\beta$, $\\beta\\ge 2$. For $\\beta>2$, the sets of initial conditions leading to collisions/ejections and the one leading to escapes/captures have positive measure. For $\\beta>2$ and $\\beta\
Green, L. M.; Murray, D. K.; Bant, A. M.; Kazarians, G.; Moyers, M. F.; Nelson, G. A.; Tran, D. T.
2001-01-01
The RBE of protons has been assumed to be equivalent to that of photons. The objective of this study was to determine whether radiation-induced DNA and chromosome damage, apoptosis, cell killing and cell cycling in organized epithelial cells was influenced by radiation quality. Thyroid-stimulating hormone-dependent Fischer rat thyroid cells, established as follicles, were exposed to gamma rays or proton beams delivered acutely over a range of physical doses. Gamma-irradiated cells were able to repair DNA damage relatively rapidly so that by 1 h postirradiation they had approximately 20% fewer exposed 3' ends than their counterparts that had been irradiated with proton beams. The persistence of free ends of DNA in the samples irradiated with the proton beam implies that either more initial breaks or a quantitatively different type of damage had occurred. These results were further supported by an increased frequency of chromosomal damage as measured by the presence of micronuclei. Proton-beam irradiation induced micronuclei at a rate of 2.4% per gray, which at 12 Gy translated to 40% more micronuclei than in comparable gamma-irradiated cultures. The higher rate of micronucleus formation and the presence of larger micronuclei in proton-irradiated cells was further evidence that a qualitatively more severe class of damage had been induced than was induced by gamma rays. Differences in the type of damage produced were detected in the apoptosis assay, wherein a significant lag in the induction of apoptosis occurred after gamma irradiation that did not occur with protons. The more immediate expression of apoptotic cells in the cultures irradiated with the proton beam suggests that the damage inflicted was more severe. Alternatively, the cell cycle checkpoint mechanisms required for recovery from such damage might not have been invoked. Differences based on radiation quality were also evident in the alpha components of cell survival curves (0.05 Gy(-1) for gamma rays, 0
Convective dissolution in anisotropic porous media
de Paoli, Marco; Zonta, Francesco; Soldati, Alfredo
2016-11-01
Solute convection in porous media at high Rayleigh-Darcy numbers has important fundamental features and may also bear implications for geological CO2 sequestration processes. With the aid of direct numerical simulations, we examine the role of anisotropic permeability γ (the vertical-to-horizontal permeability ratio) on the distribution of solutal concentration in fluid saturated porous medium. Interestingly, we find that the finite-time (short-term) amount of solute that can be dissolved in anisotropic sedimentary rocks (γ < 1 , i.e. vertical permeability smaller than horizontal permeability) is much larger than in isotropic rocks. We link this seemingly counterintuitive effect with the occurring modifications to the flow topology in the anisotropic conditions. CINECA Supercomputing Centre and ISCRA Computing Initiative are gratefully acknowledged for generous allowance of computer resources. Support from Regione Autonoma Friuli Venezia Giulia under Grant PAR FSC 2007/2013 is also gratefully acknowledged.
Statistical Anisotropy from Anisotropic Inflation
Soda, Jiro
2012-01-01
We review an inflationary scenario with the anisotropic expansion rate. An anisotropic inflationary universe can be realized by a vector field coupled with an inflaton, which can be regarded as a counter example to the cosmic no-hair conjecture. We show generality of anisotropic inflation and derive a universal property. We formulate cosmological perturbation theory in anisotropic inflation. Using the formalism, we show anisotropic inflation gives rise to the statistical anisotropy in primordial fluctuations. We also explain a method to test anisotropic inflation using the cosmic microwave background radiation (CMB).
Anisotropic hydrodynamics -- basic concepts
Florkowski, Wojciech; Ryblewski, Radoslaw; Strickland, Michael
2013-01-01
Due to the rapid longitudinal expansion of the quark-gluon plasma created in relativistic heavy ion collisions, potentially large local rest frame momentum-space anisotropies are generated. The magnitude of these momentum-space anisotropies can be so large as to violate the central assumption of canonical viscous hydrodynamical treatments which linearize around an isotropic background. In order to better describe the early-time dynamics of the quark gluon plasma, one can consider instead expanding around a locally anisotropic background which results in a dynamical framework called anisotropic hydrodynamics. In this proceedings contribution we review the basic concepts of the anisotropic hydrodynamics framework presenting viewpoints from both the phenomenological and microscopic points of view.
Quasiparticle anisotropic hydrodynamics
Alqahtani, Mubarak
2016-01-01
We study an azimuthally-symmetric boost-invariant quark-gluon plasma using quasiparticle anisotropic hydrodynamics including the effects of both shear and bulk viscosities. We compare results obtained using the quasiparticle method with the standard anisotropic hydrodynamics and viscous hydrodynamics. We consider the predictions of the three methods for the differential particle spectra and mean transverse momentum. We find that the three methods agree for small shear viscosity to entropy density ratio, $\\eta/s$, but show differences at large $\\eta/s$. Additionally, we find that the standard anisotropic hydrodynamics method shows suppressed production at low transverse-momentum compared to the other two methods, and the bulk-viscous correction can drive the primordial particle spectra negative at large $p_T$ in viscous hydrodynamics.
Anisotropic contrast optical microscope
Peev, D.; Hofmann, T.; Kananizadeh, N.; Beeram, S.; Rodriguez, E.; Wimer, S.; Rodenhausen, K. B.; Herzinger, C. M.; Kasputis, T.; Pfaunmiller, E.; Nguyen, A.; Korlacki, R.; Pannier, A.; Li, Y.; Schubert, E.; Hage, D.; Schubert, M.
2016-11-01
An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. These images are obtained from sets of multiple images obtained under various polarizer, analyzer, and compensator settings. Up to 16 independent Mueller matrix images can be obtained, while our current setup is limited to 11 images normalized by the unpolarized intensity. We demonstrate the anisotropic contrast optical microscope by measuring lithographically defined micro-patterned anisotropic filters, and we quantify the adsorption of an organic self-assembled monolayer film onto the anisotropic filter. Comparison with an isotropic glass slide demonstrates the image enhancement obtained by our method over microscopy without the use of an anisotropic filter. In our current instrument, we estimate the limit of detection for organic volumetric mass within the object plane of ≈49 fg within ≈7 × 7 μm2 object surface area. Compared to a quartz crystal microbalance with dissipation instrumentation, where contemporary limits require a total load of ≈500 pg for detection, the instrumentation demonstrated here improves
Pérez-Nadal, Guillem
2016-01-01
We consider a non-relativistic free scalar field theory with a type of anisotropic scale invariance in which the number of coordinates "scaling like time" is generically greater than one. We propose the Cartesian product of two curved spaces, with the metric of each space parameterized by the other space, as a notion of curved background to which the theory can be extended. We study this type of geometries, and find a family of extensions of the theory to curved backgrounds in which the anisotropic scale invariance is promoted to a local, Weyl-type symmetry.
Molecular anisotropic magnetoresistance
Otte, Fabian; Heinze, Stefan; Mokrousov, Yuriy
2015-12-01
Using density functional theory calculations, we demonstrate that the effect of anisotropic magnetoresistance (AMR) can be enhanced by orders of magnitude with respect to conventional bulk ferromagnets in junctions containing molecules sandwiched between ferromagnetic leads. We study ballistic transport in metal-benzene complexes contacted by 3 d transition-metal wires. We show that a gigantic AMR can arise from spin-orbit coupling effects in the leads, drastically enhanced by orbital-symmetry filtering properties of the molecules. We further discuss how this molecular anisotropic magnetoresistance (MAMR) can be tuned by the proper choice of materials and their electronic properties.
Hwu, Chyanbin
2010-01-01
As structural elements, anisotropic elastic plates find wide applications in modern technology. The plates here are considered to be subjected to not only in plane load but also transverse load. In other words, both plane and plate bending problems as well as the stretching-bending coupling problems are all explained in this book. In addition to the introduction of the theory of anisotropic elasticity, several important subjects have are discussed in this book such as interfaces, cracks, holes, inclusions, contact problems, piezoelectric materials, thermoelastic problems and boundary element a
Anisotropic models for compact stars
Maurya, S K; Ray, Saibal; Dayanandan, Baiju
2015-01-01
In the present paper we obtain an anisotropic analogue of Durgapal-Fuloria (1985) perfect fluid solution. The methodology consists of contraction of anisotropic factor $\\Delta$ by the help of both metric potentials $e^{\
Nys, Kris; Van Laethem, An; Michiels, Carine; Rubio, Noemi; Piette, Jacques G; Garmyn, Maria; Agostinis, Patrizia
2010-09-01
The signal transduction pathways leading to apoptosis of human keratinocytes responding to UVB irradiation are complex and not completely understood. Previously, we reported that in UVB-irradiated keratinocytes, p38(MAPK) instigates Bcl-2-associated X protein (Bax) activation and mitochondrial apoptosis. However, the molecular mechanism underlying the pro-apoptotic function of p38(MAPK) remained unclear. Here, we show that in UVB-treated human primary keratinocytes the activation of p38(MAPK) is necessary to upregulate Noxa, a BH3-only pro-apoptotic dominantly induced by UVB and required for apoptosis. Whereas p53-silencing was marginally cytoprotective and poorly affected Noxa expression, p38(MAPK) inhibition in p53-silenced keratinocytes or in p53(-/-) cells could still efficiently prevent Noxa induction and intrinsic apoptosis after UVB, indicating that p38(MAPK) signals mainly through p53-independent mechanisms. Furthermore, p38(MAPK) was required for the induction and activation of hypoxia-inducible factor 1 (HIF-1) in response to UVB, and HIF-1 knockdown reduced Noxa expression and apoptosis. In UVB-irradiated keratinocytes, Noxa targeted the anti-apoptotic myeloid cell leukemia sequence 1 (Mcl-1) for degradation, and small-interfering RNA (siRNA)-mediated knockdown of Noxa or p38(MAPK) inhibition restored levels of Mcl-1 and abolished apoptosis. Thus, the pro-apoptotic mechanisms orchestrated by p38(MAPK) in human keratinocytes in response to UVB involve an HIF-1/Noxa axis, which prompts the downregulation of anti-apoptotic Mcl-1, thereby favoring Bax-mediated mitochondrial apoptosis of UVB-damaged keratinocytes.
Recent progress in anisotropic hydrodynamics
Directory of Open Access Journals (Sweden)
Strickland Michael
2017-01-01
Full Text Available The quark-gluon plasma created in a relativistic heavy-ion collisions possesses a sizable pressure anisotropy in the local rest frame at very early times after the initial nuclear impact and this anisotropy only slowly relaxes as the system evolves. In a kinetic theory picture, this translates into the existence of sizable momentum-space anisotropies in the underlying partonic distribution functions, 〈 pL2〉 ≪ 〈 pT2〉. In such cases, it is better to reorganize the hydrodynamical expansion by taking into account momentum-space anisotropies at leading-order in the expansion instead of as a perturbative correction to an isotropic distribution. The resulting anisotropic hydrodynamics framework has been shown to more accurately describe the dynamics of rapidly expanding systems such as the quark-gluon plasma. In this proceedings contribution, I review the basic ideas of anisotropic hydrodynamics, recent progress, and present a few preliminary phenomenological predictions for identified particle spectra and elliptic flow.
Longitudinal fluctuations and decorrelation of anisotropic flow
Pang, Long-Gang; Petersen, Hannah; Qin, Guang-You; Roy, Victor; Wang, Xin-Nian
2016-12-01
We investigate the decorrelation of 2nd and 3rd order anisotropic flow for charged particles in two different pseudo rapidity (η) windows by varying the pseudo rapidity gap, in an event-by-event (3+1)D ideal hydrodynamic model, with fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. We visualize the parton distribution at initial state for Pb+Pb collisions at LHC and Au+Au collisions at RHIC, and demonstrate the longitudinal fluctuations originating from the asymmetry between forward and backward going participants, the fluctuations of the string length and the fluctuations due to finite number of partons at different beam energies. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation than at LHC, indicating larger longitudinal fluctuations at lower beam energies.
Indian Academy of Sciences (India)
B B Bhowmik; A Rajput
2004-06-01
Anisotropic Bianchi Type-I cosmological models have been studied on the basis of Lyra's geometry. Two types of models, one with constant deceleration parameter and the other with variable deceleration parameter have been derived by considering a time-dependent displacement field.
Caspases: An apoptosis mediator
Directory of Open Access Journals (Sweden)
Tapan Kumar Palai
2015-03-01
Full Text Available The process of programmed cell death, or apoptosis, is generally characterized by distinct morphological characteristics and energy - dependent biochemical mechanisms. Apoptosis is a widely conserved phenomenon helping many processes, including normal cell turnover, proper development and functioning of the immune system, hormone dependent atrophy etc. Inappropriate apoptosis (either low level or high level leads to many developmental abnormalities like, neurodegenerative diseases, ischemic damage, autoimmune disorders and many types of cancer. To use cells for therapeutic purposes through generating cell lines, it is critical to study the cell cycle machinery and signalling pathways that controls cell death and apoptosis. Apoptotic pathways provide a fundamental protective mechanism that decreases cellular sensitivity to damaging events and allow proper developmental process in multi-cellular organisms. Major mediator of apoptosis is a family of proteins known as caspases. There are mainly fourteen types of caspases but out of them only ten caspasese have got essential role in controlling the process of apoptosis. These ten caspases have been categorized into either initiator caspases (caspase 2, 8, 9, 10 or executioner caspases (caspase 3, 6, 7. Although various types of caspases have been identified so far, the exact mechanisms of action of these groups of proteins is still to be fully understood. The aim of this review is to provide a detail overview of role of different caspases in regulating the process of apoptosis.
Anisotropic dark energy and CMB anomalies
Battye, Richard
2009-01-01
We investigate the breaking of global statistical isotropy caused by a dark energy component with an energy-momentum tensor which has point symmetry, that could represent a cubic or hexagonal crystalline lattice. In such models Gaussian, adiabatic initial conditions created during inflation can lead to anisotropies in the cosmic microwave background whose spherical harmonic coefficients are correlated, contrary to the standard assumption. We develop an adaptation of the line of sight integration method that can be applied to models where the background energy-momentum tensor is isotropic, but whose linearized perturbations are anisotropic. We then show how this can be applied to the cases of cubic and hexagonal symmetry. We compute quantities which show that such models are indistinguishable from isotropic models even in the most extreme parameter choices, in stark contrast to models with anisotropic initial conditions based on inflation. The reason for this is that the dark energy based models contribute to ...
Fractures in anisotropic media
Shao, Siyi
Rocks may be composed of layers and contain fracture sets that cause the hydraulic, mechanical and seismic properties of a rock to be anisotropic. Coexisting fractures and layers in rock give rise to competing mechanisms of anisotropy. For example: (1) at low fracture stiffness, apparent shear-wave anisotropy induced by matrix layering can be masked or enhanced by the presence of a fracture, depending on the fracture orientation with respect to layering, and (2) compressional-wave guided modes generated by parallel fractures can also mask the presence of matrix layerings for particular fracture orientations and fracture specific stiffness. This report focuses on two anisotropic sources that are widely encountered in rock engineering: fractures (mechanical discontinuity) and matrix layering (impedance discontinuity), by investigating: (1) matrix property characterization, i.e., to determine elastic constants in anisotropic solids, (2) interface wave behavior in single-fractured anisotropic media, (3) compressional wave guided modes in parallel-fractured anisotropic media (single fracture orientation) and (4) the elastic response of orthogonal fracture networks. Elastic constants of a medium are required to understand and quantify wave propagation in anisotropic media but are affected by fractures and matrix properties. Experimental observations and analytical analysis demonstrate that behaviors of both fracture interface waves and compressional-wave guided modes for fractures in anisotropic media, are affected by fracture specific stiffness (controlled by external stresses), signal frequency and relative orientation between layerings in the matrix and fractures. A fractured layered medium exhibits: (1) fracture-dominated anisotropy when the fractures are weakly coupled; (2) isotropic behavior when fractures delay waves that are usually fast in a layered medium; and (3) matrix-dominated anisotropy when the fractures are closed and no longer delay the signal. The
Effect of inflation on anisotropic cosmologies
Energy Technology Data Exchange (ETDEWEB)
Jensen, L.G.; Stein-Schabes, J.A.
1986-03-01
The effects of anisotropic cosmologies on inflation are studied. By properly formulating the field equations it is possible to show that any model that undergoes sufficient inflation will become isotropic on scales greater than the horizon today. Furthermore, we shall show that it takes a very long time for anisotropies to become visible in the observable part of the Universe. It is interesting to note that the time scale will be independent of the Bianchi Model and of the initial anisotropy. 6 refs.
Effect of inflation on anisotropic cosmologies
Energy Technology Data Exchange (ETDEWEB)
Jensen, L.G.; Stein-Schabes, J.A.
1986-08-15
We study the effects of anisotropic cosmologies on inflation. By properly formulating the field equations it is possible to show that any model that undergoes sufficient inflation will become isotropic on scales greater than the horizon today. Furthermore, we shall show that it takes a very long time for anisotropies to become visible in the observable part of the Universe. It is interesting to note that the time scale will be independent of the Bianchi model and of the initial anisotropy.
Directory of Open Access Journals (Sweden)
Hamid Reza Momeni
2011-01-01
Full Text Available Apoptosis, a form of programmed cell death that occurs under physiologicalas well as pathological conditions, is characterized by morphological and biochemicalfeatures. While the importance of caspases in apoptosis is established,several noncaspase proteases (Ca2+-dependent proteases such as calpain mayplay a role in the execution of apoptosis. The calpain family consists of twomajor isoforms, calpain I and calpain II which require μM and mM Ca2+ concentrationsto initiate their activity. An increase in intracellular Ca2+ level isthought to trigger a cascade of biochemical processes including calpain activation.Once activated, calpains degrade membrane, cytoplasmic and nuclear substrates,leading to the breakdown of cellular architecture and finally apoptosis.The activation of calpain has been implicated in neuronal apoptosis followingspinal cord injuries and neurodegenerative diseases. This review focuses oncalpain with an emphasis on its key role in the proteolysis of cellular proteinsubstrates following apoptosis.
Directory of Open Access Journals (Sweden)
Susmita Mondal
Full Text Available The goal of cancer chemotherapy to induce multi-directional apoptosis as targeting a single pathway is unable to decrease all the downstream effect arises from crosstalk. Present study reports that Withanolide D (WithaD, a steroidal lactone isolated from Withania somnifera, induced cellular apoptosis in which mitochondria and p53 were intricately involved. In MOLT-3 and HCT116p53+/+ cells, WithaD induced crosstalk between intrinsic and extrinsic signaling through Bid, whereas in K562 and HCT116p53-/- cells, only intrinsic pathway was activated where Bid remain unaltered. WithaD showed pronounced activation of p53 in cancer cells. Moreover, lowered apoptogenic effect of HCT116p53-/- over HCT116p53+/+ established a strong correlation between WithaD-mediated apoptosis and p53. WithaD induced Bax and Bak upregulation in HCT116p53+/+, whereas increase only Bak expression in HCT116p53-/- cells, which was coordinated with augmented p53 expression. p53 inhibition substantially reduced Bax level and failed to inhibit Bak upregulation in HCT116p53+/+ cells confirming p53-dependent Bax and p53-independent Bak activation. Additionally, in HCT116p53+/+ cells, combined loss of Bax and Bak (HCT116Bax-Bak- reduced WithaD-induced apoptosis and completely blocked cytochrome c release whereas single loss of Bax or Bak (HCT116Bax-Bak+/HCT116Bax+Bak- was only marginally effective after WithaD treatment. In HCT116p53-/- cells, though Bax translocation to mitochondria was abrogated, Bak oligomerization helped the cells to release cytochrome c even before the disruption of mitochondrial membrane potential. WithaD also showed in vitro growth-inhibitory activity against an array of p53 wild type and null cancer cells and K562 xenograft in vivo. Taken together, WithaD elicited apoptosis in malignant cells through Bax/Bak dependent pathway in p53-wild type cells, whereas Bak compensated against loss of Bax in p53-null cells.
On the relativistic anisotropic configurations
Energy Technology Data Exchange (ETDEWEB)
Shojai, F. [University of Tehran, Department of Physics, Tehran (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), Foundations of Physics Group, School of Physics, Tehran (Iran, Islamic Republic of); Kohandel, M. [Alzahra University, Department of Physics and Chemistry, Tehran (Iran, Islamic Republic of); Stepanian, A. [University of Tehran, Department of Physics, Tehran (Iran, Islamic Republic of)
2016-06-15
In this paper we study anisotropic spherical polytropes within the framework of general relativity. Using the anisotropic Tolman-Oppenheimer-Volkov equations, we explore the relativistic anisotropic Lane-Emden equations. We find how the anisotropic pressure affects the boundary conditions of these equations. Also we argue that the behavior of physical quantities near the center of star changes in the presence of anisotropy. For constant density, a class of exact solution is derived with the aid of a new ansatz and its physical properties are discussed. (orig.)
Autofocus imaging: Experimental results in an anisotropic austenitic weld
Zhang, J.; Drinkwater, B. W.; Wilcox, P. D.; Hunter, A.
2012-05-01
The quality of an ultrasonic array image, especially for anisotropic material, depends on accurate information about acoustic properties. Inaccuracy of acoustic properties causes image degradation, e.g., blurring, errors in locating of reflectors and introduction of artifacts. In this paper, for an anisotropic austenitic steel weld, an autofocus imaging technique is presented. The array data from a series of beacons is captured and then used to statistically extract anisotropic weld properties by using a Monte-Carlo inversion approach. The beacon and imaging systems are realized using two separated arrays; one acts as a series of beacons and the other images these beacons. Key to the Monte-Carlo inversion scheme is a fast forward model of wave propagation in the anisotropic weld and this is based on the Dijkstra algorithm. Using this autofocus approach a measured weld map was extracted from an austenitic weld and used to reduce location errors, initially greater than 6mm, to less than 1mm.
Formation of Anisotropic Block Copolymer Gels
Liaw, Chya Yan; Shull, Kenneth; Henderson, Kevin; Joester, Derk
2011-03-01
Anisotropic, fibrillar gels are important in a variety of processes. Biomineralization is one example, where the mineralization process often occurs within a matrix of collagen or chitin fibers that trap the mineral precursors and direct the mineralization process. We wish to replicate this type of behavior within block copolymer gels. Particularly, we are interested in employing gels composed of cylindrical micelles, which are anisotropic and closely mimic biological fibers. Micelle geometry is controlled in our system by manipulating the ratio of molecular weights of the two blocks and by controlling the detailed thermal processing history of the copolymer solutions. Small-Angle X-ray Scattering and Dynamic Light Scattering are used to determine the temperature dependence of the gel formation process. Initial experiments are based on a thermally-reversible alcohol-soluble system, that can be subsequently converted to a water soluble system by hydrolysis of a poly(t-butyl methacrylate) block to a poly (methacrylic acid) block. MRSEC.
Dynamics of anisotropic f(R) cosmology
Leon, Genly
2010-01-01
We construct general anisotropic cosmological scenarios governed by an f(R) gravitational sector. Focusing then on Kantowski-Sachs geometries in the case of $R^n$-gravity we perform a detailed phase-space analysis. We find that at late times the universe can result to a state of accelerating expansion, and additionally, for a particular n-range (2
Directory of Open Access Journals (Sweden)
Bordón Elisa
2011-06-01
Full Text Available Abstract Background Either higher levels of initial DNA damage or lower levels of radiation-induced apoptosis in peripheral blood lymphocytes have been associated to increased risk for develop late radiation-induced toxicity. It has been recently published that these two predictive tests are inversely related. The aim of the present study was to investigate the combined role of both tests in relation to clinical radiation-induced toxicity in a set of breast cancer patients treated with high dose hyperfractionated radical radiotherapy. Methods Peripheral blood lymphocytes were taken from 26 consecutive patients with locally advanced breast carcinoma treated with high-dose hyperfractioned radical radiotherapy. Acute and late cutaneous and subcutaneous toxicity was evaluated using the Radiation Therapy Oncology Group morbidity scoring schema. The mean follow-up of survivors (n = 13 was 197.23 months. Radiosensitivity of lymphocytes was quantified as the initial number of DNA double-strand breaks induced per Gy and per DNA unit (200 Mbp. Radiation-induced apoptosis (RIA at 1, 2 and 8 Gy was measured by flow cytometry using annexin V/propidium iodide. Results Mean DSB/Gy/DNA unit obtained was 1.70 ± 0.83 (range 0.63-4.08; median, 1.46. Radiation-induced apoptosis increased with radiation dose (median 12.36, 17.79 and 24.83 for 1, 2, and 8 Gy respectively. We observed that those "expected resistant patients" (DSB values lower than 1.78 DSB/Gy per 200 Mbp and RIA values over 9.58, 14.40 or 24.83 for 1, 2 and 8 Gy respectively were at low risk of suffer severe subcutaneous late toxicity (HR 0.223, 95%CI 0.073-0.678, P = 0.008; HR 0.206, 95%CI 0.063-0.677, P = 0.009; HR 0.239, 95%CI 0.062-0.929, P = 0.039, for RIA at 1, 2 and 8 Gy respectively in multivariate analysis. Conclusions A radiation-resistant profile is proposed, where those patients who presented lower levels of initial DNA damage and higher levels of radiation induced apoptosis were at low
Gardiner, Thomas
2013-10-01
Anisotropic thermal diffusion in magnetized plasmas is an important physical phenomena for a diverse set of physical conditions ranging from astrophysical plasmas to MFE and ICF. Yet numerically simulating this phenomenon accurately poses significant challenges when the computational mesh is misaligned with respect to the magnetic field. Particularly when the temperature gradients are unresolved, one frequently finds entropy violating solutions with heat flowing from cold to hot zones for χ∥ /χ⊥ >=102 which is substantially smaller than the range of interest which can reach 1010 or higher. In this talk we present a new implicit algorithm for solving the anisotropic thermal diffusion equations and demonstrate its characteristics on what has become a fairly standard set of test problems in the literature. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2013-5687A.
Review of anisotropic flow correlations in ultrarelativistic heavy-ion collisions
Zhou, You
2016-01-01
Anisotropic flow phenomena is a key probe of the existence of Quark-Gluon Plasma. Several new observable associated with correlations between anisotropic flow harmonics are developed, which are expected to be sensitive to the initial fluctuations and transport properties of the created matter in heavy ion collisions. I review recent developments of correlations of anisotropic flow harmonics. The experimental measurements, together with the comparisons to theoretical model calculations, open up new opportunities of exploring novel QCD dynamics in heavy-ion collisions.
Anisotropic Power-law Inflation
Kanno, Sugumi; Watanabe, Masa-aki
2010-01-01
We study an inflationary scenario in supergravity model with a gauge kinetic function. We find exact anisotropic power-law inflationary solutions when both the potential function for an inflaton and the gauge kinetic function are exponential type. The dynamical system analysis tells us that the anisotropic power-law inflation is an attractor for a large parameter region.
van Kats, C. M.
2008-10-01
The driving forces for fundamental research in colloid science are the ability to manage the material properties of colloids and to unravel the forces that play a role between colloids to be able to control and understand the processes where colloids play an important role. Therefore we are searching for colloidal materials with specific physical properties to better understand our surrounding world.Until recently research in colloid science was mainly focused on spherical (isotropic) particles. Monodisperse spherical colloids serve as a model system as they exhibit similar phase behaviour as molecular and atomic systems. Nevertheless, in many cases the spherical shape is not sufficient to reach the desired research goals. Recently the more complex synthesis methods of anisotropic model colloids has strongly developed. This thesis should be regarded as a contribution to this research area. Anisotropic colloids can be used as a building block for complex structures and are expected not only to lead to the construction of full photonic band gap materials. They will also serve as new, more realistic, models systems for their molecular analogues. Therefore the term ‘molecular colloids” is sometimes used to qualify these anisotropic colloidal particles. In the introduction of this thesis, we give an overview of the main synthesis techniques for anisotropic colloids. Chapter 2 describes the method of etching silicon wafers to construct monodisperse silicon rods. They subsequently were oxidized and labeled (coated) with a fluorescent silica layer. The first explorative phase behaviour of these silica rods was studied. The particles showed a nematic ordering in charge stabilized suspensions. Chapter 3 describes the synthesis of colloidal gold rods and the (mesoporous) silica coating of gold rods. Chapter 4 describes the physical and optical properties of these particles when thermal energy is added. This is compared to the case where the particles are irradiated with
Anisotropic power-law k-inflation
Ohashi, Junko; Tsujikawa, Shinji
2013-01-01
It is known that power-law k-inflation can be realized for the Lagrangian $P=Xg(Y)$, where $X=-(\\partial \\phi)^2/2$ is the kinetic energy of a scalar field $\\phi$ and $g$ is an arbitrary function in terms of $Y=Xe^{\\lambda \\phi/M_{pl}}$ ($\\lambda$ is a constant and $M_{pl}$ is the reduced Planck mass). In the presence of a vector field coupled to the inflaton with an exponential coupling $f(\\phi) \\propto e^{\\mu \\phi/M_{pl}}$, we show that the models with the Lagrangian $P=Xg(Y)$ generally give rise to anisotropic inflationary solutions with $\\Sigma/H=constant$, where $\\Sigma$ is an anisotropic shear and $H$ is an isotropic expansion rate. Provided these anisotropic solutions exist in the regime where the ratio $\\Sigma/H$ is much smaller than 1, they are stable attractors irrespective of the forms of $g(Y)$. We apply our results to concrete models of k-inflation such as the generalized dilatonic ghost condensate/the DBI model and we numerically show that the solutions with different initial conditions converge...
Decorrelation of anisotropic flow along the longitudinal direction
Energy Technology Data Exchange (ETDEWEB)
Pang, Long-Gang [Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Petersen, Hannah [Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Qin, Guang-You [Central China Normal University, Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Wuhan (China); Roy, Victor [Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Wang, Xin-Nian [Central China Normal University, Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Wuhan (China); Lawrence Berkeley National Laboratory, Nuclear Science Division MS70R0319, Berkeley, CA (United States)
2016-04-15
The initial energy density distribution and fluctuations in the transverse direction lead to anisotropic flow of final hadrons through collective expansion in high-energy heavy-ion collisions. Fluctuations along the longitudinal direction, on the other hand, can result in decorrelation of anisotropic flow in different regions of pseudorapidity (η). Decorrelation of the 2nd- and 3rd-order anisotropic flow with different η gaps for final charged hadrons in high-energy heavy-ion collisions is studied in an event-by-event (3+1)D ideal hydrodynamic model with fully fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The decorrelation is found to consist of both a linear twist and random fluctuation of the event plane angles. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation, indicating larger longitudinal fluctuations at lower beam energies. Our study also calls into question some of the current experimental methods for measuring anisotropic flow and the quantitative extraction of transport coefficients through comparisons to hydrodynamic simulations that do not include longitudinal fluctuations. (orig.)
Decorrelation of anisotropic flow along the longitudinal direction
Pang, Long-Gang; Petersen, Hannah; Qin, Guang-You; Roy, Victor; Wang, Xin-Nian
2016-04-01
The initial energy density distribution and fluctuations in the transverse direction lead to anisotropic flow of final hadrons through collective expansion in high-energy heavy-ion collisions. Fluctuations along the longitudinal direction, on the other hand, can result in decorrelation of anisotropic flow in different regions of pseudorapidity ( η . Decorrelation of the 2nd- and 3rd-order anisotropic flow with different η gaps for final charged hadrons in high-energy heavy-ion collisions is studied in an event-by-event (3+1)D ideal hydrodynamic model with fully fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The decorrelation is found to consist of both a linear twist and random fluctuation of the event plane angles. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation, indicating larger longitudinal fluctuations at lower beam energies. Our study also calls into question some of the current experimental methods for measuring anisotropic flow and the quantitative extraction of transport coefficients through comparisons to hydrodynamic simulations that do not include longitudinal fluctuations.
Anisotropic Inflation with General Potentials
Shi, Jiaming; Qiu, Taotao
2015-01-01
Anomalies in recent observational data indicate that there might be some "anisotropic hair" generated in an inflation period. To obtain general information about the effects of this anisotropic hair to inflation models, we studied anisotropic inflation models that involve one vector and one scalar using several types of potentials. We determined the general relationship between the degree of anisotropy and the fraction of the vector and scalar fields, and concluded that the anisotropies behave independently of the potentials. We also generalized our study to the case of multi-directional anisotropies.
Wave velocities in a pre-stressed anisotropic elastic medium
Indian Academy of Sciences (India)
M D Sharma; Neetu Garg
2006-04-01
Modiﬁed Christoffel equations are derived for three-dimensional wave propagation in a general anisotropic medium under initial stress.The three roots of a cubic equation deﬁne the phase velocities of three quasi-waves in the medium.Analytical expressions are used to calculate the directional derivatives of phase velocities.These derivatives are,further,used to calculate the group velocities and ray directions of the three quasi-waves in a pre-stressed anisotropic medium.Effect of initial stress on wave propagation is observed through the deviations in phase velocity,group velocity and ray direction for each of the quasi-waves.The variations of these deviations with the phase direction are plotted for a numerical model of general anisotropic medium with triclinic/ monoclinic/orthorhombic symmetry.
Gradient expansion for anisotropic hydrodynamics
Florkowski, Wojciech; Ryblewski, Radoslaw; Spaliński, Michał
2016-12-01
We compute the gradient expansion for anisotropic hydrodynamics. The results are compared with the corresponding expansion of the underlying kinetic-theory model with the collision term treated in the relaxation time approximation. We find that a recent formulation of anisotropic hydrodynamics based on an anisotropic matching principle yields the first three terms of the gradient expansion in agreement with those obtained for the kinetic theory. This gives further support for this particular hydrodynamic model as a good approximation of the kinetic-theory approach. We further find that the gradient expansion of anisotropic hydrodynamics is an asymptotic series, and the singularities of the analytic continuation of its Borel transform indicate the presence of nonhydrodynamic modes.
Gradient expansion for anisotropic hydrodynamics
Florkowski, Wojciech; Spaliński, Michał
2016-01-01
We compute the gradient expansion for anisotropic hydrodynamics. The results are compared with the corresponding expansion of the underlying kinetic-theory model with the collision term treated in the relaxation time approximation. We find that a recent formulation of anisotropic hydrodynamics based on an anisotropic matching principle yields the first three terms of the gradient expansion in agreement with those obtained for the kinetic theory. This gives further support for this particular hydrodynamic model as a good approximation of the kinetic-theory approach. We further find that the gradient expansion of anisotropic hydrodynamics is an asymptotic series, and the singularities of the analytic continuation of its Borel transform indicate the presence of non-hydrodynamic modes.
Photon states in anisotropic media
Indian Academy of Sciences (India)
Deepak Kumar
2002-08-01
Quantum aspects of optical polarization are discussed for waves traveling in anisotropic dielectric media with a view to relate the dynamics of polarization with that of photon spin and its manipulation by classical polarizers.
Anisotropic assembly and pattern formation
von Brecht, James H.; Uminsky, David T.
2017-01-01
We investigate the role of anisotropy in two classes of individual-based models for self-organization, collective behavior and self-assembly. We accomplish this via first-order dynamical systems of pairwise interacting particles that incorporate anisotropic interactions. At a continuum level, these models represent the natural anisotropic variants of the well-known aggregation equation. We leverage this framework to analyze the impact of anisotropic effects upon the self-assembly of co-dimension one equilibrium structures, such as micelles and vesicles. Our analytical results reveal the regularizing effect of anisotropy, and isolate the contexts in which anisotropic effects are necessary to achieve dynamical stability of co-dimension one structures. Our results therefore place theoretical limits on when anisotropic effects can be safely neglected. We also explore whether anisotropic effects suffice to induce pattern formation in such particle systems. We conclude with brief numerical studies that highlight various aspects of the models we introduce, elucidate their phase structure and partially validate the analysis we provide.
Light propagation through anisotropic turbulence.
Toselli, Italo; Agrawal, Brij; Restaino, Sergio
2011-03-01
A wealth of experimental data has shown that atmospheric turbulence can be anisotropic; in this case, a Kolmogorov spectrum does not describe well the atmospheric turbulence statistics. In this paper, we show a quantitative analysis of anisotropic turbulence by using a non-Kolmogorov power spectrum with an anisotropic coefficient. The spectrum we use does not include the inner and outer scales, it is valid only inside the inertial subrange, and it has a power-law slope that can be different from a Kolmogorov one. Using this power spectrum, in the weak turbulence condition, we analyze the impact of the power-law variations α on the long-term beam spread and scintillation index for several anisotropic coefficient values ς. We consider only horizontal propagation across the turbulence cells, assuming circular symmetry is maintained on the orthogonal plane to the propagation direction. We conclude that the anisotropic coefficient influences both the long-term beam spread and the scintillation index by the factor ς(2-α).
Decorrelation of anisotropic flows along the longitudinal direction
Pang, Long-Gang; Qin, Guang-You; Roy, Victor; Wang, Xin-Nian
2015-01-01
The initial energy density distribution and fluctuation in the transverse direction lead to anisotropic flows of final hadrons through collective expansion in high-energy heavy-ion collisions. Fluctuations along the longitudinal direction, on the other hand, can result in decorrelation of anisotropic flows in different regions of pseudo rapidity ($\\eta$). Decorrelation of the $2$nd and $3$rd order anisotropic flows with different $\\eta$ gaps for final charged hadrons in high-energy heavy-ion collisions is studied in an event-by-event (3+1)D ideal hydrodynamic model with fully fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. The decorrelation of anisotropic flows of final hadrons with large $\\eta$ gaps are found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The decorrelation is found to consist of both a linear twist and random fluctuation of the event-plane angles. The agreement between our r...
Quench dynamics of the anisotropic Heisenberg model.
Liu, Wenshuo; Andrei, Natan
2014-06-27
We develop an analytical approach for the study of the quench dynamics of the anisotropic Heisenberg model (XXZ model) on the infinite line. We present the exact time-dependent wave functions after a quench in an integral form for any initial state and for any anisotropy Δ by means of a generalized Yudson contour representation. We calculate the evolution of several observables from two particular initial states: starting from a local Néel state we calculate the time evolution of the antiferromagnetic order parameter-staggered magnetization; starting from a state with consecutive flipped spins (1) we calculate the evolution of the local magnetization and express it in terms of the propagation of magnons and bound state excitations, and (2) we predict the evolution of the induced spin currents. These predictions can be confronted with experiments in ultracold gases in optical lattices. We also show how the "string" solutions of Bethe ansatz equations emerge naturally from the contour approach.
Hyperspherical theory of anisotropic exciton
Muljarov, E A; Tikhodeev, S G; Bulatov, A E; Birman, Joseph L; 10.1063/1.1286772
2012-01-01
A new approach to the theory of anisotropic exciton based on Fock transformation, i.e., on a stereographic projection of the momentum to the unit 4-dimensional (4D) sphere, is developed. Hyperspherical functions are used as a basis of the perturbation theory. The binding energies, wave functions and oscillator strengths of elongated as well as flattened excitons are obtained numerically. It is shown that with an increase of the anisotropy degree the oscillator strengths are markedly redistributed between optically active and formerly inactive states, making the latter optically active. An approximate analytical solution of the anisotropic exciton problem taking into account the angular momentum conserving terms is obtained. This solution gives the binding energies of moderately anisotropic exciton with a good accuracy and provides a useful qualitative description of the energy level evolution.
Anisotropic inflation in Finsler spacetime
Li, Xin; Chang, Zhe
2015-01-01
We suggest the universe is Finslerian in the stage of inflation. The Finslerian background spacetime breaks rotational symmetry and induces parity violation. The primordial power spectrum is given for quantum fluctuation of the inflation field. It depends not only on the magnitude of wavenumber but also on the preferred direction. We derive the gravitational field equations in the perturbed Finslerian background spacetime, and obtain a conserved quantity outside the Hubble horizon. The angular correlation coefficients are presented in our anisotropic inflation model. The parity violation feature of Finslerian background spacetime requires that the anisotropic effect only appears in angular correlation coefficients if $l'=l+1$. The numerical results of the angular correlation coefficients are given to describe the anisotropic effect.
Anisotropically structured magnetic aerogel monoliths
Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus
2014-10-01
Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and
Anisotropic hydrodynamics: Motivation and methodology
Energy Technology Data Exchange (ETDEWEB)
Strickland, Michael
2014-06-15
In this proceedings contribution I review recent progress in our understanding of the bulk dynamics of relativistic systems that possess potentially large local rest frame momentum-space anisotropies. In order to deal with these momentum-space anisotropies, a reorganization of relativistic viscous hydrodynamics can be made around an anisotropic background, and the resulting dynamical framework has been dubbed “anisotropic hydrodynamics”. I also discuss expectations for the degree of momentum-space anisotropy of the quark–gluon plasma generated in relativistic heavy ion collisions at RHIC and LHC from second-order viscous hydrodynamics, strong-coupling approaches, and weak-coupling approaches.
Vaish, Vivek; Rana, Chandan; Piplani, Honit; Vaiphei, Kim; Sanyal, Sankar Nath
2014-03-01
In the present study we have elaborated the putative mechanisms could be followed by the non-steroidal anti-inflammatory drugs (NSAIDs) viz. Sulindac and Celecoxib in the regulation of cell cycle checkpoints along with tumor suppressor proteins to achieve their chemopreventive effects in the initial stages of experimental colorectal cancer. Male Sprague-Dawley rats were administered with 1,2-dimethylhydrazine dihydrochloride (DMH) to produce early stages of colorectal carcinogenesis. The mRNA expression profiles of various target genes were analyzed by RT-PCR and validated by quantitative real-time PCR, whereas protein expression was analyzed by Western blotting. Nuclear localization of transcription factors or other nuclear proteins was analyzed by electrophoretic mobility shift assay and immunofluorescence. Flowcytometry was performed to analyze the differential apoptotic events and cell cycle regulation. Molecular docking studies with different target proteins were also performed to deduce the various putative mechanisms of action followed by Sulindac and Celecoxib. We observed that DMH administration has abruptly increased the proliferation of colonic cells which is macroscopically visible in the form of multiple plaque lesions and co-relates with the disturbed molecular mechanisms of cell cycle regulation. However, co-administration of NSAIDs has shown regulatory effects on cell cycle checkpoints via induction of various tumor suppressor proteins. We may conclude that Sulindac and Celecoxib could possibly follow p53/p21 mediated regulation of cell proliferation, where down regulation of NF-κB signaling and activation of PPARγ might serve as important additional events in vivo.
Quantum electrodynamics of inhomogeneous anisotropic media
Energy Technology Data Exchange (ETDEWEB)
Lopez, Adrian E.R.; Lombardo, Fernando C. [Ciudad Universitaria, Departamento de Fisica Juan Jose Giambiagi, Buenos Aires (Argentina); IFIBA CONICET-UBA, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)
2015-02-01
In this work we calculate the closed time path generating functional for the electromagnetic (EM) field interacting with inhomogeneous anisotropic matter. For this purpose, we first find a general expression for the electromagnetic field's influence action from the interaction of the field with a composite environment consisting in the quantum polarization degrees of freedom in each point of space, at arbitrary temperatures, connected to thermal baths. Then we evaluate the generating functional for the gauge field, in the temporal gauge, by implementing the Faddeev-Popov procedure. Finally, through the point-splitting technique, we calculate closed expressions for the energy, the Poynting vector, and the Maxwell tensor in terms of the Hadamard propagator. We show that all the quantities have contributions from the field's initial conditions and also from the matter degrees of freedom. Throughout the whole work we discuss how the gauge invariance must be treated in the formalism when the EM-field is interacting with inhomogeneous anisotropic matter. We study the electrodynamics in the temporal gauge, obtaining the EM-field's equation and a residual condition. Finally we analyze the case of the EM-field in bulk material and also discuss several general implications of our results in relation with the Casimir physics in a non-equilibrium scenario. (orig.)
Anisotropic Poisson Processes of Cylinders
Spiess, Malte
2010-01-01
Main characteristics of stationary anisotropic Poisson processes of cylinders (dilated k-dimensional flats) in d-dimensional Euclidean space are studied. Explicit formulae for the capacity functional, the covariance function, the contact distribution function, the volume fraction, and the intensity of the surface area measure are given which can be used directly in applications.
Magnetic relaxation in anisotropic magnets
DEFF Research Database (Denmark)
Lindgård, Per-Anker
1971-01-01
The line shape and the kinematic and thermodynamic slowing down of the critical and paramagnetic relaxation in axially anisotropic materials are discussed. Kinematic slowing down occurs only in the longitudinal relaxation function. The thermodynamic slowing down occurs in either the transverse or...
Failure in imperfect anisotropic materials
DEFF Research Database (Denmark)
Legarth, Brian Nyvang
2005-01-01
The fundamental cause of crack growth, namely nucleation and growth of voids, is investigated numerically for a two phase imperfect anisotropic material. A unit cell approach is adopted from which the overall stress strain is evaluated. Failure is observed as a sudden stress drop and depending...
Quantum electrodynamics of inhomogeneous anisotropic media
Lopez, Adrian E Rubio
2014-01-01
In this work we calculate the closed time path (CTP) generating functional for the electromagnetic (EM) field interacting with inhomogeneous anisotropic matter. For this purpose, we first find a general expression for the electromagnetic field's influence action from the interaction of the field with a composite environment consisting in the quantum polarization degrees of freedom in each point of space, at arbitrary temperatures, connected to thermal baths. Then, we evaluate the generating functional for the gauge field, in the temporal gauge, by implementing the Faddeev-Popov procedure. Finally, through the point-splitting technique, we calculate closed expressions for the energy, the Poynting vector and the Maxwell tensor in terms of the Hadamard propagator. We show that all the quantities have contributions from the field's initial conditions and also from the matter degrees of freedom. Throughout the whole work we discuss and give insights about how the gauge invariance must be treated in the formalism w...
Conductivities in an anisotropic medium
Khimphun, Sunly; Lee, Bum-Hoon; Park, Chanyong
2016-10-01
In order to imitate the anisotropic medium of a condensed matter system, we take into account an Einstein-Maxwell-dilaton-axion model as a dual gravity theory where the anisotropy is caused by different momentum relaxations. This gravity model allows an anisotropic charged black hole solution. On this background, we investigate how the linear responses of vector modes like electric, thermoelectric, and thermal conductivities rely on the anisotropy. We find that the electric conductivity in the low frequency limit shows a Drude peak and that, in the intermediate frequency regime, it reveals the power law behavior. Specifically, when the anisotropy increases, the exponent of the power law becomes smaller. In addition, we find that a critical value for the anisotropy exists at which the dc conductivity reaches to its maximum value.
Anisotropic Inflation and Cosmological Observations
Emami, Razieh
2015-01-01
Recent observations opened up a new window on the inflationary model building. As it was firstly reported by the WMAP data, there may be some indications of statistical anisotropy on the CMB map, although the statistical significance of these findings are under debate. Motivated by these observations, people begun considering new inflationary models which may lead to statistical anisotropy. The simplest possible way to construct anisotropic inflation is to introduce vector fields. During the course of this thesis, we study models of anisotropic inflation and their observational implications such as power spectrum, bispectrum etc. Firstly we build a new model, which contains the gauge field which breaks the conformal invariance while preserving the gauge invariance. We show that in these kind of models, there can be an attractor phase in the evolution of the system when the back-reaction of the gauge field becomes important in the evolution of the inflaton field. We then study the cosmological perturbation the...
Conductivities in an anisotropic medium
Khimphun, Sunly; Park, Chanyong
2016-01-01
In order to imitate anisotropic medium of a condensed matter system, we take into account an Einstein-Maxwell-dilaton-axion model as a dual gravity theory where the anisotropy is caused by different momentum relaxations. This gravity model allows an anisotropic charged black hole solution. On this background, we investigate how the linear responses of vector modes like electric, thermoelectric, and thermal conductivities rely on the anisotropy. We find that the electric conductivity in low frequency limit shows a Drude peak and that in the intermediate frequency regime it reveals the power law behavior. Especially, when the anisotropy increases the exponent of the power law becomes smaller. In addition, we find that there exist a critical value for the anisotropy at which the DC conductivity reaches to its maximum value.
A new model for spherically symmetric anisotropic compact star
Energy Technology Data Exchange (ETDEWEB)
Maurya, S.K.; Dayanandan, Baiju [University of Nizwa, Department of Mathematical and Physical Sciences, College of Arts and Science, Nizwa (Oman); Gupta, Y.K. [Raj Kumar Goel Institute of Technology, Department of Mathematics, Ghaziabad, UP (India); Ray, Saibal [Government College of Engineering and Ceramic Technology, Department of Physics, Kolkata, West Bengal (India)
2016-05-15
In this article we obtain a new anisotropic solution for Einstein's field equations of embedding class one metric. The solution represents realistic objects such as Her X-1 and RXJ 1856-37. We perform a detailed investigation of both objects by solving numerically the Einstein field equations with anisotropic pressure. The physical features of the parameters depend on the anisotropic factor i.e. if the anisotropy is zero everywhere inside the star then the density and pressures will become zero and the metric turns out to be flat. We report our results and compare with the above mentioned two compact objects as regards a number of key aspects: the central density, the surface density onset and the critical scaling behaviour, the effective mass and radius ratio, the anisotropization with isotropic initial conditions, adiabatic index and red shift. Along with this we have also made a comparison between the classical limit and theoretical model treatment of the compact objects. Finally we discuss the implications of our findings for the stability condition in a relativistic compact star. (orig.)
A new model for spherically symmetric anisotropic compact star
Maurya, S K; Dayanandan, Baiju; Ray, Saibal
2016-01-01
In this article we obtain a new anisotropic solution for Einstein's field equation of embedding class one metric. The solution is representing the realistic objects such as $Her~X-1$ and $RXJ~1856-37$. We perform detailed investigation of both objects by solving numerically the Einstein field equations under with anisotropic pressure. The physical features of the parameters depend on the anisotropic factor i.e. if anisotropy is zero everywhere inside the star then the density and pressures will become zero and metric turns out to be flat. We report our results and compare with the above mentioned two compact objects on a number of key aspects: the central density, the surface density onset and the critical scaling behavior, the effective mass and radius ratio, the anisotropization with isotropic initial conditions, adiabatic index and red shift. Along with this we have also made a comparison between the classical limit and theoretical model treatment of the compact objects. Finally we discuss the implications...
A new model for spherically symmetric anisotropic compact star
Maurya, S. K.; Gupta, Y. K.; Dayanandan, Baiju; Ray, Saibal
2016-05-01
In this article we obtain a new anisotropic solution for Einstein's field equations of embedding class one metric. The solution represents realistic objects such as Her X-1 and RXJ 1856-37. We perform a detailed investigation of both objects by solving numerically the Einstein field equations with anisotropic pressure. The physical features of the parameters depend on the anisotropic factor i.e. if the anisotropy is zero everywhere inside the star then the density and pressures will become zero and the metric turns out to be flat. We report our results and compare with the above mentioned two compact objects as regards a number of key aspects: the central density, the surface density onset and the critical scaling behaviour, the effective mass and radius ratio, the anisotropization with isotropic initial conditions, adiabatic index and red shift. Along with this we have also made a comparison between the classical limit and theoretical model treatment of the compact objects. Finally we discuss the implications of our findings for the stability condition in a relativistic compact star.
Axially symmetric volume constrained anisotropic mean curvature flow
Palmer, Bennett
2011-01-01
We study the long time existence theory for a non local flow associated to a free boundary problem for a trapped non liquid drop. The drop has free boundary components on two horizontal plates and its free energy is anisotropic and axially symmetric. For axially symmetric initial surfaces with sufficiently large volume, we show that the flow exists for all time. Numerical simulations of the curvature flow are presented.
Biferale, Luca; Toschi, Federico
2001-01-01
We present the first measurements of anisotropic statistical fluctuations in perfectly homogeneous turbulent flows. We address both problems of intermittency in anisotropic sectors and hierarchical ordering of anisotropies on a direct numerical simulation of a three dimensional random Kolmogorov flo
Remarks on inhomogeneous anisotropic cosmology
Kaya, Ali
2016-08-01
Recently a new no-global-recollapse argument was given for some inhomogeneous and anisotropic cosmologies that utilizes surface deformation by the mean curvature flow. In this paper we discuss important properties of the mean curvature flow of spacelike surfaces in Lorentzian manifolds. We show that singularities may form during cosmic evolution, and the theorems forbidding the global recollapse lose their validity. The time evolution of the spatial scalar curvature that may kinematically prevent the recollapse is determined in normal coordinates, which shows the impact of inhomogeneities explicitly. Our analysis indicates a caveat in numerical solutions that give rise to inflation.
Spin precession in anisotropic cosmologies
Energy Technology Data Exchange (ETDEWEB)
Kamenshchik, A.Yu. [Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); L. D. Landau Institute for Theoretical Physics, Moscow (Russian Federation); INFN, Bologna (Italy); Teryaev, O.V. [Joint Institute for Nuclear Research, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); Lomonosov Moscow State University, Moscow (Russian Federation)
2016-05-15
We consider the precession of a Dirac particle spin in some anisotropic Bianchi universes. This effect is present already in the Bianchi-I universe. We discuss in some detail the geodesics and the spin precession for both the Kasner and the Heckmann-Schucking solutions. In the Bianchi-IX universe the spin precession acquires the chaotic character due to the stochasticity of the oscillatory approach to the cosmological singularity. The related helicity flip of fermions in the very early universe may produce the sterile particles contributing to dark matter. (orig.)
Anisotropic and nonlinear optical waveguides
Someda, CG
1992-01-01
Dielectric optical waveguides have been investigated for more than two decades. In the last ten years they have had the unique position of being simultaneously the backbone of a very practical and fully developed technology, as well as an extremely exciting area of basic, forefront research. Existing waveguides can be divided into two sets: one consisting of waveguides which are already in practical use, and the second of those which are still at the laboratory stage of their evolution. This book is divided into two separate parts: the first dealing with anisotropic waveguides, an
Anisotropic hydrodynamics and the early-thermalization puzzle
Florkowski, Wojciech
2012-01-01
The framework of anisotropic hydrodynamics is used in 3+1 dimensions to analyze behavior of matter produced in ultra-relativistic heavy-ion collisions. The model predictions for the hadronic transverse-momentum spectra, directed and elliptic flows, and the HBT radii are presented. We show that the effects of the initial anisotropy of pressure may be compensated by appropriate adjustment of the initial energy density. In this way, the final hadronic observables become insensitive to the early stage dynamics and the early thermalization puzzle may be circumvented.
Lecoanet, Daniel; Quataert, Eliot
2012-01-01
We study the effects of anisotropic thermal conduction along magnetic field lines on an accelerated contact discontinuity in a weakly collisional plasma. We first perform a linear stability analysis similar to that used to derive the Rayleigh-Taylor instability (RTI) dispersion relation. We find that anisotropic conduction is only important for compressible modes, as incompressible modes are isothermal. Modes grow faster in the presence of anisotropic conduction, but growth rates do not change by more than a factor of order unity. We next run fully non-linear numerical simulations of a contact discontinuity with anisotropic conduction. The non-linear evolution can be thought of as a superposition of three physical effects: temperature diffusion due to vertical conduction, the RTI, and the heat flux driven buoyancy instability (HBI). In simulations with RTI-stable contact discontinuities, the temperature discontinuity spreads due to vertical heat conduction. This occurs even for initially horizontal magnetic f...
Thick brane isotropization in the 5D anisotropic standing wave braneworld model
Gogberashvili, Merab; Malagon-Morejon, Dagoberto; Mora-Luna, Refugio Rigel; Nucamendi, Ulises
2014-01-01
We study a smooth cosmological solution of the 5D anisotropic standing wave braneworld model generated by gravity coupled to a phantom-like scalar field. In this model the brane emits anisotropic waves into the bulk with different amplitudes along different spatial dimensions. We found a natural mechanism which isotropizes the braneworld, rendering a 3-brane with de Sitter symmetry embedded in a 5D de Sitter space-time for a wide class of initial conditions. The resulting thick geometrical braneworld (a de Sitter 3-brane) possesses a series of remarkable features. By explicitly solving the bulk field equations we are able to give a physical interpretation of the anisotropic dissipation: as the anisotropic energy on the 3-brane rapidly leaks into the bulk, through the nontrivial Weyl tensor components, the bulk becomes less isotropic.
Local deposition of anisotropic nanoparticles using scanning electrochemical microscopy (SECM).
Fedorov, Roman G; Mandler, Daniel
2013-02-28
We demonstrate localized electrodeposition of anisotropic metal nanoobjects, namely Au nanorods (GNR), on indium tin oxide (ITO) using scanning electrochemical microscopy (SECM). A gold microelectrode was the source of the gold ions whereby double pulse chronoamperometry was employed to generate initially Au seeds which were further grown under controlled conditions. The distance between the microelectrode and the ITO surface as well as the different experimental parameters (electrodeposition regime, solution composition and temperature) were optimized to produce faceted gold seeds with the required characteristics (size and distribution). Colloidal chemical synthesis was successfully exploited for better understanding the role of the surfactant and different additives in breaking the crystallographic symmetry and anisotropic growth of GNR. Experiments performed in a conventional three-electrode cell revealed the most appropriate electrochemical conditions allowing high yield synthesis of nanorods with well-defined shape as well as nanocubes and bipyramids.
Gamma-beam propagation in the anisotropic medium
Maisheev, V A
2000-01-01
Propagation of gamma-beam in the anisotropic medium is considered. The simpliest example of such a medium of the general type is a combination of the two linearly polarized monochromatic laser waves with different frequencies (dichromatic wave). The optical properties of this combination are described with the use of the permittivity tensor. The refractive indices and polarization characteristics of normal electromagnetic waves propagating in the anisotropic medium are found. The relations, describing variations of gamma-beam intensity and Stokes parameters as functions of propagation length are obtained. The influence of laser wave intensity on the propagation process are calculated. The gamma-beam intensity losses in the dichromatic wave depend on the initial circular polarization of gamma-quanta. This effect is also applied to the single crystals, which are oriented in some regions of coherent pair production. In principle, the single crystal sensitivity to a circular polarization can be used for determina...
Sur, Shouvik; Lee, Sung-Sik
2016-11-01
We study non-Fermi-liquid states that arise at the quantum critical points associated with the spin density wave (SDW) and charge density wave (CDW) transitions in metals with twofold rotational symmetry. We use the dimensional regularization scheme, where a one-dimensional Fermi surface is embedded in (3 -ɛ ) -dimensional momentum space. In three dimensions, quasilocal marginal Fermi liquids arise both at the SDW and CDW critical points: the speed of the collective mode along the ordering wave vector is logarithmically renormalized to zero compared to that of Fermi velocity. Below three dimensions, however, the SDW and CDW critical points exhibit drastically different behaviors. At the SDW critical point, a stable anisotropic non-Fermi-liquid state is realized for small ɛ , where not only time but also different spatial coordinates develop distinct anomalous dimensions. The non-Fermi liquid exhibits an emergent algebraic nesting as the patches of Fermi surface are deformed into a universal power-law shape near the hot spots. Due to the anisotropic scaling, the energy of incoherent spin fluctuations disperse with different power laws in different momentum directions. At the CDW critical point, on the other hand, the perturbative expansion breaks down immediately below three dimensions as the interaction renormalizes the speed of charge fluctuations to zero within a finite renormalization group scale through a two-loop effect. The difference originates from the fact that the vertex correction antiscreens the coupling at the SDW critical point whereas it screens at the CDW critical point.
Modelling of CMUTs with Anisotropic Plates
DEFF Research Database (Denmark)
la Cour, Mette Funding; Christiansen, Thomas Lehrmann; Jensen, Jørgen Arendt;
2012-01-01
Traditionally, CMUTs are modelled using the isotropic plate equation and this leads to deviations between analytical calculations and FEM simulations. In this paper, the deflection profile and material parameters are calculated using the anisotropic plate equation. It is shown that the anisotropic...
ANISOTROPIC BIQUADRATIC ELEMENT WITH SUPERCLOSE RESULT
Institute of Scientific and Technical Information of China (English)
Dongyang SHI; Shipeng MAO; Hui LIANG
2006-01-01
The main aim of this paper is to study the convergence of biquadratic finite element for the second order problem on anisotropic meshes. By using some novel approaches and techniques, the optimal error estimates are obtained. At the same time, the anisotropic superclose results are also achieved. Furthermore, the numerical results are given to demonstrate our theoretical analysis.
Efficient Wavefield Extrapolation In Anisotropic Media
Alkhalifah, Tariq
2014-07-03
Various examples are provided for wavefield extrapolation in anisotropic media. In one example, among others, a method includes determining an effective isotropic velocity model and extrapolating an equivalent propagation of an anisotropic, poroelastic or viscoelastic wavefield. The effective isotropic velocity model can be based upon a kinematic geometrical representation of an anisotropic, poroelastic or viscoelastic wavefield. Extrapolating the equivalent propagation can use isotopic, acoustic or elastic operators based upon the determined effective isotropic velocity model. In another example, non-transitory computer readable medium stores an application that, when executed by processing circuitry, causes the processing circuitry to determine the effective isotropic velocity model and extrapolate the equivalent propagation of an anisotropic, poroelastic or viscoelastic wavefield. In another example, a system includes processing circuitry and an application configured to cause the system to determine the effective isotropic velocity model and extrapolate the equivalent propagation of an anisotropic, poroelastic or viscoelastic wavefield.
Designing Anisotropic Inflation with Form Fields
Ito, Asuka
2015-01-01
We study inflation with anisotropic hair induced by form fields. In four dimensions, the relevant form fields are gauge (one-form) fields and two-form fields. Assuming the exponential form of potential and gauge kinetic functions, we find new exact power-law solutions endowed with anisotropic hair. We also explore the phase space of anisotropic inflation and find fixed points corresponding to the exact power-law solutions. Moreover, we perform the stability analysis around the fixed points to reveal the structure of the phase space. It turns out that one of the fixed points becomes an attractor and others (if any) are saddle points. In particular, the one corresponding to anisotropic inflation becomes an attractor when it exists. We also argue that various anisotropic inflation models can be designed by choosing coupling constants.
Prosser, William H. (Inventor); Kriz, Ronald D. (Inventor); Fitting, Dale W. (Inventor)
1993-01-01
An ultrasonic wave is applied to an anisotropic sample material in an initial direction and an angle of flux deviation of the ultrasonic wave front is measured from this initial direction. This flux deviation angle is induced by the unknown applied load. The flux shift is determined between this flux deviation angle and a previously determined angle of flux deviation of an ultrasonic wave applied to a similar anisotropic reference material under an initial known load condition. This determined flux shift is then compared to a plurality of flux shifts of a similarly tested, similar anisotropic reference material under a plurality of respective, known load conditions, whereby the load applied to the particular anisotropic sample material is determined. A related method is disclosed for determining the fiber orientation from known loads and a determined flux shift.
Warm anisotropic inflationary universe model
Energy Technology Data Exchange (ETDEWEB)
Sharif, M.; Saleem, Rabia [University of the Punjab, Department of Mathematics, Lahore (Pakistan)
2014-02-15
This paper is devoted to the study of warm inflation using vector fields in the background of a locally rotationally symmetric Bianchi type I model of the universe. We formulate the field equations, and slow-roll and perturbation parameters (scalar and tensor power spectra as well as their spectral indices) in the slow-roll approximation. We evaluate all these parameters in terms of the directional Hubble parameter during the intermediate and logamediate inflationary regimes by taking the dissipation factor as a function of the scalar field as well as a constant. In each case, we calculate the observational parameter of interest, i.e., the tensor-scalar ratio in terms of the inflaton. The graphical behavior of these parameters shows that the anisotropic model is also compatible with WMAP7 and the Planck observational data. (orig.)
Warm Anisotropic Inflationary Universe Model
Sharif, M
2014-01-01
This paper is devoted to study the warm inflation using vector fields in the background of locally rotationally symmetric Bianchi type I universe model. We formulate the field equations, slow-roll and perturbation parameters (scalar and tensor power spectra as well as their spectral indices) under slow-roll approximation. We evaluate all these parameters in terms of directional Hubble parameter during intermediate and logamediate inflationary regimes by taking the dissipation factor as a function of scalar field as well as a constant. In each case, we calculate the observational parameter of interest, i.e., tensor-scalar ratio in terms of inflation. The graphical behavior of these parameters shows that the anisotropic model is also compatible with WMAP7 and Planck observational data.
Gravitational Baryogenesis after Anisotropic Inflation
Fukushima, Mitsuhiro; Maeda, Kei-ichi
2016-01-01
The gravitational baryogensis may not generate a sufficient baryon asymmetry in the standard thermal history of the Universe when we take into account the gravitino problem. Hence it has been suggested that anisotropy of the Universe can enhance the generation of the baryon asymmetry through the increase of the time change of the Ricci scalar curvature. We study the gravitational baryogenesis in the presence of anisotropy, which is produced at the end of an anisotropic inflation. Although we confirm that the generated baryon asymmetry is enhanced compared with the original isotropic cosmological model, taking into account the constraint on the anisotropy by the recent CMB observations, we find that it is still difficult to obtain the observed baryon asymmetry only through the gravitational baryogenesis without suffering from the gravitino problem.
Anisotropic inflation from extra dimensions
Litterio, M; Amendola, L; Dyrek, A; Litterio, Marco; Amendola, Luca; Dyrek, Andrzej
1995-01-01
Vacuum multidimensional cosmological models with internal spaces being compact n-dimensional Lie group manifolds are considered. Products of 3-spheres and SU(3) manifold (a novelty in cosmology) are studied. It turns out that the dynamical evolution of the internal space drives an accelerated expansion of the external world (power law inflation). This generic solution (attractor in a phase space) is determined by the Lie group space without any fine tuning or arbitrary inflaton potentials. Matter in the four dimensions appears in the form of a number of scalar fields representing anisotropic scale factors for the internal space. Along the attractor solution the volume of the internal space grows logarithmically in time. This simple and natural model should be completed by mechanisms terminating the inflationary evolution and transforming the geometric scalar fields into ordinary particles.
Spatially anisotropic Heisenberg kagome antiferromagnet
Apel, W.; Yavors'kii, T.; Everts, H.-U.
2007-04-01
In the search for spin-1/2 kagome antiferromagnets, the mineral volborthite has recently been the subject of experimental studies (Hiroi et al 2001 J. Phys. Soc. Japan 70 3377; Fukaya et al 2003 Phys. Rev. Lett. 91 207603; Bert et al 2004 J. Phys.: Condens. Matter 16 S829; Bert et al 2005 Phys. Rev. Lett. 95 087203). It has been suggested that the magnetic properties of this material are described by a spin-1/2 Heisenberg model on the kagome lattice with spatially anisotropic exchange couplings. We report on investigations of the {\\mathrm {Sp}}(\\mathcal {N}) symmetric generalization of this model in the large \\mathcal {N} limit. We obtain a detailed description of the dependence of possible ground states on the anisotropy and on the spin length S. A fairly rich phase diagram with a ferrimagnetic phase, incommensurate phases with and without long-range order and a decoupled chain phase emerges.
Gravitational baryogenesis after anisotropic inflation
Fukushima, Mitsuhiro; Mizuno, Shuntaro; Maeda, Kei-ichi
2016-05-01
The gravitational baryogensis may not generate a sufficient baryon asymmetry in the standard thermal history of the Universe when we take into account the gravitino problem. Hence, it has been suggested that anisotropy of the Universe can enhance the generation of the baryon asymmetry through the increase of the time change of the Ricci scalar curvature. We study the gravitational baryogenesis in the presence of anisotropy, which is produced at the end of an anisotropic inflation. Although we confirm that the generated baryon asymmetry is enhanced compared with the original isotropic cosmological model, taking into account the constraint on the anisotropy by the recent CMB observations, we find that it is still difficult to obtain the observed baryon asymmetry only through the gravitational baryogenesis without suffering from the gravitino problem.
Anisotropic grid adaptation in LES
Toosi, Siavash; Larsson, Johan
2016-11-01
The modeling errors depend directly on the grid (or filter) spacing in turbulence-resolving simulations (LES, DNS, DES, etc), and are typically at least as significant as the numerical errors. This makes adaptive grid-refinement complicated, since it prevents the estimation of the local error sources through numerical analysis. The present work attempts to address this difficulty with a physics-based error-source indicator that accounts for the anisotropy in the smallest resolved scales, which can thus be used to drive an anisotropic grid-adaptation process. The proposed error indicator is assessed on a sequence of problems, including turbulent channel flow and flows in more complex geometries. The formulation is geometrically general and applicable to complex geometries.
Yagi, Kent
2015-01-01
Certain physical quantities that characterize neutron stars and quark stars (e.g. their mass, spin angular momentum and quadrupole moment) are interrelated in a way that is approximately insensitive to their internal structure. Such approximately universal relations are useful to break degeneracies in data analysis for future radio, X-ray and gravitational wave observations. Although the pressure inside compact stars is most likely nearly isotropic, certain scenarios have been put forth that suggest otherwise, for example due to phase transitions. We here investigate whether pressure anisotropy affects the approximate universal relations and whether it prevents their use in future observations. We achieve this by numerically constructing slowly-rotating and tidally-deformed, anisotropic, compact stars in General Relativity to third order in spin. We find that anisotropy affects the universal relations only weakly; the relations become less universal by a factor of 1.5-3 relative to the isotropic case, but rem...
Anisotropic microstructure near the sun
Coles, W. A.; Grall, R. R.; Spangler, S. R.; Sakurai, T.; Harmon, J. K.
1996-07-01
Radio scattering observations provide a means of measuring a two-dimensional projection of the three-dimensional spatial spectrum of electron density, i.e., in the plane perpendicular to the line of sight. Earlier observations have shown that the microstructure at scales of the order of 10 km becomes highly field-aligned inside of 10 Rsolar [Armstrong et al., 1990]. Earlier work has also shown that density fluctuations at scales larger than 1000 km have a Kolmogorov spectrum, whereas the smaller scale structure has a flatter spectrum and is considerably enhanced above the Kolmogorov ``background'' [Coles et al., 1991]. Here we present new observations made during 1990 and 1992. These confirm the earlier work, which was restricted to one source on a few days, but they suggest that the anisotropy changes abruptly near 6 Rsolar which was not clear in the earlier data. The axial ratio measurements are shown on Figure 1 below. The new observations were made with a more uniform sampling of the spatial plane. They show that contours of constant correlation are elliptical. This is apparently inconsistent with the spatial correlation of the ISEE-3 magnetic field which shows a ``Maltese Cross'' shape [Matthaeus et al., 1990]. However this inconsistency may be only apparent: the magnetic field and density correlations need not have the same shape; the scale of the magnetic field correlations is at least 4 orders of magnitude larger; they are much further from the sun; and they are point measurements whereas ours are path-integrated. We also made two simultaneous measurements, at 10 Rsolar, of the anisotropy on scales of 200 to 4000 km. Significant anisotropy was seen on the smaller scales, but the larger scale structure was essentially isotropic. This suggests that the process responsible for the anisotropic microstructure is independent of the larger scale isotropic turbulence. It is then tempting to speculate that the damping of this anisotropic process inside of 6 Rsolar
Anisotropic flow and flow fluctuations at the large hadron collider
Zhou, You
One of the fundamental questions in the phenomenology of Quantum Chromodynamics (QCD) is what the properties of matter are at the extreme densities and temperatures where quarks and gluons are in a new state of matter, the so-called Quark Gluon Plasma (QGP). Collisions of high-energy heavy-ions at the CERN Large Hadron Collider (LHC), allow us to create and study the properties of such a system in the laboratory. Anisotropic flow (vn) is strong evidence for the existence of QGP, and has been described as one of the most important observations measured in the ultra-relativistic heavy-ion collisions. In this thesis, the anisotropic flow of not only charged particles but also identified particles are presented. In addition, the investigations of correlations and fluctuations of both flow angle (symmetry plane) and magnitude were discussed. The main goal of this thesis is to understand the nature of anisotropic flow and its response to the initial geometry of the created system as well as its fluctuations.
Phenomenological Anisotropic Study of Surface Finish in Pack Rolling
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
A phenomenological anisotropic model has been presented for the surface roughness modeling of pack rolling. The model is an assembly of grains in different orientations and sizes. The grain size is assumed to be in log-normal distribution. To model the macro anisotropic mechanical behavior of the grains induced by the slip deformation, the grains are assumed as isolated anisotropic units. The units have different mechanic behavior, and depend on the crystallographic orientations and the external loading as well as the interaction of the adjunctive grains. In the paper,the material properties of the grains are assumed as uniform distributions. The roughness of the contact surfaces depends on the distribution types and the scatters of the distributions. It is found that the initial roughness of the contact surfaces has a little influence on the surface roughness when the rolling deformation is large. The comparison between the phenomenological model and crystallographic model shows that the phenomenological model can also give out a reasonable result, while it only takes much less CPU time. The agreement between the single sheet model and the pack rolling model shows that in a certain degree the pack rolling model can be replaced by the single sheet model to decrease the CPU time.
Shaped beam scattering by an anisotropic particle
Chen, Zhenzhen; Zhang, Huayong; Huang, Zhixiang; Wu, Xianliang
2017-03-01
An exact semi-analytical solution to the electromagnetic scattering from an optically anisotropic particle illuminated by an arbitrarily shaped beam is proposed. The scattered fields and fields within the anisotropic particle are expanded in terms of spherical vector wave functions. The unknown expansion coefficients are determined by using the boundary conditions and the method of moments scheme. For incidence of a Gaussian beam, zero-order Bessel beam and Hertzian electric dipole radiation, numerical results of the normalized differential scattering cross section are given to a uniaxial, gyrotropic anisotropic spheroid and circular cylinder of finite length. The scattering properties are analyzed concisely.
Research on anisotropic parameters by synthetic seismogram
Institute of Scientific and Technical Information of China (English)
FAN Xiao-ping; LI Qing-he; YANG Cong-jie
2005-01-01
ased on the extensive-dilatancy anisotropy theory, the method of synthetic seismogram is used to estimate the anisotropic parameters. The advantages of the method lie in that it avoids the singularity resolution and saves calculation time of computer by using the eigenvalue and eigenvector analytical expressions of Christoffel equation, at the same time, the result is tested by coherence function. The test result reveals there exists a fine linear relation between original records and synthetic records, indicating the anisotropic parameters estimated by synthetic seismogram can reflect and describe the anisotropic characteristics of the given region medium.
Finite-volume scheme for anisotropic diffusion
Energy Technology Data Exchange (ETDEWEB)
Es, Bram van, E-mail: bramiozo@gmail.com [Centrum Wiskunde & Informatica, P.O. Box 94079, 1090GB Amsterdam (Netherlands); FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands); Koren, Barry [Eindhoven University of Technology (Netherlands); Blank, Hugo J. de [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands)
2016-02-01
In this paper, we apply a special finite-volume scheme, limited to smooth temperature distributions and Cartesian grids, to test the importance of connectivity of the finite volumes. The area of application is nuclear fusion plasma with field line aligned temperature gradients and extreme anisotropy. We apply the scheme to the anisotropic heat-conduction equation, and compare its results with those of existing finite-volume schemes for anisotropic diffusion. Also, we introduce a general model adaptation of the steady diffusion equation for extremely anisotropic diffusion problems with closed field lines.
A new algorithm for anisotropic solutions
Indian Academy of Sciences (India)
M Chaisi; S D Maharaj
2006-02-01
We establish a new algorithm that generates a new solution to the Einstein field equations, with an anisotropic matter distribution, from a seed isotropic solution. The new solution is expressed in terms of integrals of an isotropic gravitational potential; and the integration can be completed exactly for particular isotropic seed metrics. A good feature of our approach is that the anisotropic solutions necessarily have an isotropic limit. We find two examples of anisotropic solutions which generalise the isothermal sphere and the Schwarzschild interior sphere. Both examples are expressed in closed form involving elementary functions only.
Anisotropic inflation in Gauss-Bonnet gravity
Energy Technology Data Exchange (ETDEWEB)
Lahiri, Sayantani [ZARM, University of Bremen,Am Falltrum, 28359 Bremen (Germany)
2016-09-19
We study anisotropic inflation with Gauss-Bonnet correction in presence of a massless vector field. In this scenario, exact anisotropic power-law inflation is realized when the inflaton potential, gauge coupling function and the Gauss-Bonnet coupling are exponential functions. We show that anisotropy becomes proportional to two slow-roll parameters of the theory and hence gets enhanced in presence of quadratic curvature corrections. The stability analysis reveals that anisotropic power-law solutions remain stable over a substantially large parameter region.
Imprints of Anisotropic Inflation on the CMB
Watanabe, Masa-aki; Soda, Jiro
2010-01-01
We study the imprints of anisotropic inflation on the CMB temperature fluctuations and polarizations. The statistical anisotropy stems not only from the direction dependence of curvature and tensor perturbations, but also from the cross correlation between curvature and tensor perturbations, and the linear polarization of tensor perturbations. We show that off-diagonal $TB$ and $EB$ spectrum as well as on- and off-diagonal $TT, EE, BB, TE$ spectrum are induced from anisotropic inflation. We emphasize that the off-diagonal spectrum induced by the cross correlation could be a characteristic signature of anisotropic inflation.
The Effect of Anisotropic Conduction on the Thermal Instability in the Interstellar Medium
Choi, Ena
2011-01-01
Thermal instability (TI) can strongly affect the structure and dynamics of the interstellar medium (ISM) in the Milky Way and other disk galaxies. Thermal conduction plays an important role in the TI by stabilizing small scales and limiting the size of the smallest condensates. In the magnetized ISM, however, heat is conducted anisotropically (primarily along magnetic field lines). We investigate the effects of anisotropic thermal conduction on the nonlinear regime of the TI by performing two-dimensional magnetohydrodynamic simulations. We present models with magnetic fields of different initial geometries and strengths, and compare them to hydrodynamic models with isotropic conduction. We find anisotropic conduction does not significantly alter the overall density and temperature statistics in the saturated state of the TI. However, it can strongly affect the shapes and sizes of cold clouds formed by the TI. For example, for uniform initial fields long filaments of cold gas are produced that are reminiscent ...
Method of determining load in anisotropic non-crystalline materials using energy flux deviation
Prosser, William H. (Inventor); Kriz, Ronald D. (Inventor); Fitting, Dale W. (Inventor)
1994-01-01
An ultrasonic wave is applied to an anisotropic sample material in an initial direction and the intensity of the ultrasonic wave is measured on an opposite surface of the sample material by two adjacent receiving points located in an array of receiving points. A ratio is determined between the measured intensities of two adjacent receiving points, the ratio being indicative of an angle of flux deviation from the initial direction caused by an unknown applied load. This determined ratio is then compared to a plurality of ratios of a similarly tested, similar anisotropic reference material under a plurality of respective, known load conditions, whereby the load applied to the particular anisotropic sample material is determined. A related method is disclosed for determining the fiber orientation from known loads and a determined flux shift.
Fluidization of tissues by cell division and apoptosis.
Ranft, Jonas; Basan, Markus; Elgeti, Jens; Joanny, Jean-François; Prost, Jacques; Jülicher, Frank
2010-12-07
During the formation of tissues, cells organize collectively by cell division and apoptosis. The multicellular dynamics of such systems is influenced by mechanical conditions and can give rise to cell rearrangements and movements. We develop a continuum description of tissue dynamics, which describes the stress distribution and the cell flow field on large scales. In the absence of division and apoptosis, we consider the tissue to behave as an elastic solid. Cell division and apoptosis introduce stress sources that, in general, are anisotropic. By combining cell number balance with dynamic equations for the stress source, we show that the tissue effectively behaves as a viscoelastic fluid with a relaxation time set by the rates of division and apoptosis. If the system is confined in a fixed volume, it reaches a homeostatic state in which division and apoptosis balance. In this state, cells undergo a diffusive random motion driven by the stochasticity of division and apoptosis. We calculate the expression for the effective diffusion coefficient as a function of the tissue parameters and compare our results concerning both diffusion and viscosity to simulations of multicellular systems using dissipative particle dynamics.
Moon, Hee-Sun; Kim, Boyun; Gwak, HyeRan; Suh, Dong Hoon; Song, Yong Sang
2016-04-01
Metformin, an oral biguanide for the treatment of type II diabetes, has been shown to have anticancer effects in ovarian cancer. Energy starvation induced by metformin causes endoplasmic reticulum stress-mediated unfolded protein response (UPR) and autophagy. UPR and autophagy act as a survival or death mechanism in cells. In this study, we observed that metformin-induced apoptosis was relieved by autophagy and the PERK/eIF2α pathway in ovarian cancer cells, but not in peripheral blood mononuclear cells (PBMC) or 'normal' ovarian surface epithelial cells (OSE). Increased PARP cleavage and increased LC3B-II with ATG5-ATG12 complex suggested the induction of apoptosis and autophagy, respectively, in metformin-treated ovarian cancer cells. Accumulation of acidic vacuoles in the cytoplasm and downregulation of p62 further supported late-stage autophagy. Interestingly, metformin induced interdependent activation between autophagy and the UPR, especially the PERK/eIF2α pathway. Inhibition of autophagy-induced PERK inhibition, and vice versa, were demonstrated using small molecular inhibitors (PERK inhibitor I, GSK2606414; autophagy inhibitor, 3-MA, and BafA1). Moreover, autophagy and PERK activation protected ovarian cancer cells against metformin-induced apoptosis. Metformin treatment in the presence of inhibitors of PERK and autophagy, however, had no cytotoxic effects on OSE or PBMC. In conclusion, these results suggest that inhibition of autophagy and PERK can enhance the selective anticancer effects of metformin on ovarian cancer cells. © 2015 Wiley Periodicals, Inc.
Spatial interpolation approach based on IDW with anisotropic spatial structures
Li, Jia; Duan, Ping; Sheng, Yehua; Lv, Haiyang
2015-12-01
In many interpolation methods, with its simple interpolation principle, Inverse distance weighted (IDW) interpolation is one of the most common interpolation method. There are anisotropic spatial structures with actual geographical spatial phenomenon. When the IDW interpolation is used, anisotropic spatial structures should be considered. Geostatistical theory has a characteristics of exploring anisotropic spatial structures. In this paper, spatial interpolation approach based on IDW with anisotropic spatial structures is proposed. The DEM data is tested in this paper to prove reliability of the IDW interpolation considering anisotropic spatial structures. Experimental results show that IDW interpolation considering anisotropic spatial structures can improve interpolation precision when sampling data has anisotropic spatial structures feature.
Gravitational collapse, shear-free anisotropic radiating star
Tewari, B C
2015-01-01
We present a class of exact solutions of Einstein field equations for a shear-free spherically symmetric anisotropic fluid undergoing radial heat flow. The interior metric fulfilled all the relevant physical and thermodynamic conditions and matched with Vaidya exterior metric over the boundary. Initially the interior solutions represent a static configuration of dissipative fluid which then gradually starts evolving into radiating collapse. The apparent luminosity observed by the distant observer at rest at infinity and the effective surface temperature are zero in remote past at the instance when collapse begins and at the stage when collapsing configuration reach the horizon of the black hole.
Quantum cosmology in an anisotropic n-dimensional universe
Alves-Júnior, F A P; Barreto, A B; Romero, C
2016-01-01
We investigate quantum cosmological models in an n-dimensional anisotropic universe in the presence of a massless scalar field. Our basic inspiration comes from Chodos and Detweiler's classical model which predicts an interesting behaviour of the extra dimension, shrinking down as time goes by. We work in the framework of a recent geometrical scalar-tensor theory of gravity. Classically, we obtain two distinct type of solutions. One of them has an initial singularity while the other represents a static universe considered as a whole. By using the canonical approach to quantum cosmology, we investigate how quantum effects could have had an influence in the past history of these universes.
Cytochrome c and insect cell apoptosis
Institute of Scientific and Technical Information of China (English)
Kai-Yu Liu; Hong Yang; Jian-Xin Peng; Hua-Zhu Hong
2012-01-01
The role ofcytochrome c in insect cell apoptosis has drawn considerable attention and has been subject to considerable controversy.In Drosophila,the majority of studies have demonstrated that cytochrome c may not be involved in apoptosis,although there are conflicting reports.Cytochrome c is not released from mitochondria into the cytosol and activation of the initiator caspase Dronc or effector caspase Drice is not associated with cytochrome c during apoptosis in Drosophila SL2 cells or BG2 cells.Cytochrome c failed to induce caspase activation and promote caspase activation in Drosophila cell lysates,but remarkably caused caspase activation in extracts from human cells.Knockdown of cytochrome c does not protect cells from apoptosis and over-expression of cytochrome c also does not promote apoptosis.Structural analysis has revealed that cytochrome c is not required for Dapaf-1 complex assembly.In Lepidoptera,the involvement of cytochrome c in apoptosis has been demonstrated by the accumulating evidence.Cytochrome c release from mitochondria into cytosol has been observed in different cell lines such as Spodoptera frugiperda Sf9,Spodoptera litura S1-1 and Lymantria dispar LdFB.Silencing of cytochrome c expression significantly affected apoptosis and activation of caspase and the addition of cytochrome c to cell-free extracts results in caspase activation,suggesting the activation of caspase is dependent on cytochrome c.Although Apaf- 1 has not been identified in Lepidoptera,the inhibitor of apoptosome formation can inhibit apoptosis and caspase activation.Cytochrome c may be exclusively required for Lepidoptera apoptosis.
Anisotropic rectangular metric for polygonal surface remeshing
Pellenard, Bertrand
2013-06-18
We propose a new method for anisotropic polygonal surface remeshing. Our algorithm takes as input a surface triangle mesh. An anisotropic rectangular metric, defined at each triangle facet of the input mesh, is derived from both a user-specified normal-based tolerance error and the requirement to favor rectangle-shaped polygons. Our algorithm uses a greedy optimization procedure that adds, deletes and relocates generators so as to match two criteria related to partitioning and conformity.
Overview of anisotropic flow measurements from ALICE
Directory of Open Access Journals (Sweden)
Zhou You
2016-01-01
Full Text Available Anisotropic flow is an important observable to study the properties of the hot and dense matter, the Quark Gluon Plasma (QGP, created in heavy-ion collisions. Measurements of anisotropic flow for inclusive and identified charged hadrons are reported in Pb–Pb, p–Pb and pp collisions with the ALICE detector. The comparison of experimental measurements to various theoretical calculations are also presented in these proceedings.
Inflation in anisotropic scalar-tensor theories
Energy Technology Data Exchange (ETDEWEB)
Pimentel, L.O.; Stein-Schabes, J.
1989-01-05
The existence of an inflationary phase in anisotropic scalar-tensor theories is investigated by means of a conformal transformation that allows us to rewrite these theories as gravity minimally coupled to a scalar field with a non-trivial potential. We then use the explicit form of the potential and the no hair theorem to conclude that there is an inflationary phase in all open or flat anisotropic spacetimes in these theories. Several examples are constructed where the effect becomes manifest.
Inflation in anisotropic scalar-tensor theories
Pimentel, Luis O.; Stein-Schabes, Jaime
1988-01-01
The existence of an inflationary phase in anisotropic Scalar-Tensor Theories is investigated by means of a conformal transformation that allows us to rewrite these theories as gravity minimally coupled to a scalar field with a nontrivial potential. The explicit form of the potential is then used and the No Hair Theorem concludes that there is an inflationary phase in all open or flat anisotropic spacetimes in these theories. Several examples are constructed where the effect becomes manifest.
Radar velocity tomography in anisotropic media
Energy Technology Data Exchange (ETDEWEB)
Kim, Jung Ho; Cho, Seong Jun; Yi Myeong Jong; Chung, Seung Hwan [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)
1996-12-01
Radar tomography inversion method was developed in the elliptic anisotropic environment with the parametrization of maximum, minimum velocity, and the direction of symmetry axis. Nonlinear least-square method with smoothness constraint was adopted as inversion scheme. Newly developed algorithm was successfully tested with the 2-D numerical cross-borehole data in isotropic environment. Seismic data from physical modelling in partially anisotropic environment was also inverted and compared with the reconstruction technique assuming isotropic media. We could confirm the effectiveness of our algorithm, even though the tested data were generated from isotropic or partially anisotropic media. Cross-hole radar field data in limestone area in Korea was analyzed that the limestone bedrock is systematically anisotropic in the sense of radar application. The data set was inverted with the new anisotropy algorithm. The anisotropic effect in the data was corrected and also inverted for the comparison through the algorithm with isotropic assumption. Applying two different algorithm and comparing the various images, the tomographic image of maximum velocity from anisotropic inversion could give the most excellent way to visualize underground. An addition to the high resolution image, we could grasp some information on the material type from the feature of maximum velocity distribution the degree of anisotropy which can be inferred from the ratio of maximum and minimum velocity. The newly developed algorithm will be expected to provide a good way to image underground, especially in sedimentary or metamorphosed bedrock. (author). 9 refs., 21 figs.
Progress in Anisotropic Plasma Physics
Romatschke, P; Romatschke, Paul; Strickland, Michael
2004-01-01
In 1959 Weibel demonstrated that when a QED plasma has a temperature anisotropy there exist unstable transverse magnetic excitations which grow exponentially fast. In this paper we will review how to determine the growth rates for these unstable modes in the weak-coupling and ultrarelativistic limits in which the collective behavior is describable in terms are so-called "hard-loops". We will show that in this limit QCD is subject to instabilities which are analogous to the Weibel instability in QED. The presence of such instabilities dominates the early time evolution of a highly anisotropic plasma; however, at longer times it is expected that these instabilities will saturate (condense). I will discuss how the presence of non-linear interactions between the gluons complicates the determination of the saturated state. In order to discuss this I present the generalization of the Braaten-Pisarski isotropic hard-thermal-loop effective action to a system with a temperature anisotropy in the parton distribution fu...
Spin precession in anisotropic media
Raes, B.; Cummings, A. W.; Bonell, F.; Costache, M. V.; Sierra, J. F.; Roche, S.; Valenzuela, S. O.
2017-02-01
We generalize the diffusive model for spin injection and detection in nonlocal spin structures to account for spin precession under an applied magnetic field in an anisotropic medium, for which the spin lifetime is not unique and depends on the spin orientation. We demonstrate that the spin precession (Hanle) line shape is strongly dependent on the degree of anisotropy and on the orientation of the magnetic field. In particular, we show that the anisotropy of the spin lifetime can be extracted from the measured spin signal, after dephasing in an oblique magnetic field, by using an analytical formula with a single fitting parameter. Alternatively, after identifying the fingerprints associated with the anisotropy, we propose a simple scaling of the Hanle line shapes at specific magnetic field orientations that results in a universal curve only in the isotropic case. The deviation from the universal curve can be used as a complementary means of quantifying the anisotropy by direct comparison with the solution of our generalized model. Finally, we applied our model to graphene devices and find that the spin relaxation for graphene on silicon oxide is isotropic within our experimental resolution.
Implementation of an anisotropic damage material model using general second order damage tensor
Niazi, Muhammad; Wisselink, Harm; Meinders, Timo; Horn, ten Carel; Mori, K.; Pietrzyk, M.; Kusiak, J.; Majta, J.; Hartley, P.; Lin, J.
2010-01-01
Damage in metals is mainly the process of the initiation and growth of voids. With the growing complexity in materials and forming proc-esses, it becomes inevitable to include anisotropy in damage (tensorial damage variable). Most of the anisotropic damage models define the damage tensor in the prin
Bound dipole solitary solutions in anisotropic nonlocal self-focusing media
DEFF Research Database (Denmark)
Mamaev, A.V.; Zozulya, A.A.; Mezentsev, V.K.;
1997-01-01
We find and analyze bound dipole solitary solutions in media with anisotropic nonlocal photorefractive material response. The dipole solutions consist of two elliptically shaped Gaussian-type beams separated by several diameters, and with a pi phase shift between their fields. Spatial evolution...... of two initially round Gaussian beams and their convergence to the above dipole solution is demonstrated experimentally....
Spatial anisotropy： a method to study anisotropic flow in heavy ion collisions
Institute of Scientific and Technical Information of China (English)
CUI Xiang-Li; LU Yan; WANG Xiao-Lian; PENG Ru
2011-01-01
We introduce a method to study anisotropic flow parameter v n as a collective probe to Quark Gluon Plasma in relativistic heavy ion collisions. The emphasis is put on the use of the Fourier expansion of initial spatial azimuthal distributions of participa
Ubiquitination in apoptosis signaling
van de Kooij, L.W.
2014-01-01
The work described in this thesis focuses on ubiquitination and protein degradation, with an emphasis on how these processes regulate apoptosis signaling. More specifically, our aims were: 1. To increase the understanding of ubiquitin-mediated regulation of apoptosis signaling. 2. To identify the E3
Calpains, mitochondria, and apoptosis.
Smith, Matthew A; Schnellmann, Rick G
2012-10-01
Mitochondrial activity is critical for efficient function of the cardiovascular system. In response to cardiovascular injury, mitochondrial dysfunction occurs and can lead to apoptosis and necrosis. Calpains are a 15-member family of Ca(2+)-activated cysteine proteases localized to the cytosol and mitochondria, and several have been shown to regulate apoptosis and necrosis. For example, in endothelial cells, Ca(2+) overload causes mitochondrial calpain 1 cleavage of the Na(+)/Ca(2+) exchanger leading to mitochondrial Ca(2+) accumulation. Also, activated calpain 1 cleaves Bid, inducing cytochrome c release and apoptosis. In renal cells, calpains 1 and 2 promote apoptosis and necrosis by cleaving cytoskeletal proteins, which increases plasma membrane permeability and cleavage of caspases. Calpain 10 cleaves electron transport chain proteins, causing decreased mitochondrial respiration and excessive activation, or inhibition of calpain 10 activity induces mitochondrial dysfunction and apoptosis. In cardiomyocytes, calpain 1 activates caspase 3 and poly-ADP ribose polymerase during tumour necrosis factor-α-induced apoptosis, and calpain 1 cleaves apoptosis-inducing factor after Ca(2+) overload. Many of these observations have been elucidated with calpain inhibitors, but most calpain inhibitors are not specific for calpains or a specific calpain family member, creating more questions. The following review will discuss how calpains affect mitochondrial function and apoptosis within the cardiovascular system.
Necking of anisotropic micro-films with strain-gradient effects
DEFF Research Database (Denmark)
Legarth, Brian Nyvang
2008-01-01
Necking of stubby micro-films of aluminum is investigated numerically by considering tension of a specimen with an initial imperfection used to onset localisation. Plastic anisotropy is represented by two different yield criteria and strain-gradient effects are accounted for using the visco......-plastic finite strain model. Furthermore, the model is extended to isotropic anisotropic hardening (evolving anisotropy). For isotropic hardening plastic anisotropy affects the predicted overall nominal stress level, while the peak stress remains at an overall logarithmic strain corresponding to the hardening...... exponent. This holds true for both local and nonlocal materials. Anisotropic hardening delays the point of maximum overall nominal stress....
Existence and uniqueness of global solutions for the modified anisotropic 3D Navier−Stokes equations
Bessaih, Hakima
2016-01-27
We study a modified three-dimensional incompressible anisotropic Navier−Stokes equations. The modification consists in the addition of a power term to the nonlinear convective one. This modification appears naturally in porous media when a fluid obeys the Darcy−Forchheimer law instead of the classical Darcy law. We prove global in time existence and uniqueness of solutions without assuming the smallness condition on the initial data. This improves the result obtained for the classical 3D incompressible anisotropic Navier−Stokes equations.
Epithelial Cell Apoptosis and Lung Remodeling
Institute of Scientific and Technical Information of China (English)
Kazuyoshi Kuwano
2007-01-01
Lung epithelium is the primary site of lung damage in various lung diseases. Epithelial cell apoptosis has been considered to be initial event in various lung diseases. Apoptosis signaling is classically composed of two principle pathways. One is a direct pathway from death receptor ligation to caspase cascade activation and cell death. The other pathway triggered by stresses such as drugs, radiation, infectious agents and reactive oxygen species is mediated by mitochondria. Endoplasmic reticulum has also been shown to be the organelle to mediate apoptosis.Epithelial cell death is followed by remodeling processes, which consist of epithelial and fibroblast activation,cytokine production, activation of coagulation pathway, neoangiogenesis, re-epithelialization and fibrosis.Epithelial and mesenchymal interaction plays important roles in these processes. Further understanding of apoptosis signaling and its regulation by novel strategies may lead to effective treatments against various lung diseases. We review the recent advances in the understanding of apoptosis signaling and discuss the involvement of apoptosis in lung remodeling.
Collisionless magnetic reconnection under anisotropic MHD approximation
Hirabayashi, Kota; Hoshino, Masahiro
We study the formation of slow-mode shocks in collisionless magnetic reconnection by using one- and two-dimensional collisionless magneto-hydro-dynamic (MHD) simulations based on the double adiabatic approximation, which is an important step to bridge the gap between the Petschek-type MHD reconnection model accompanied by a pair of slow shocks and the observational evidence of the rare occasion of in-situ slow shock observation. According to our results, a pair of slow shocks does form in the reconnection layer. The resultant shock waves, however, are quite weak compared with those in an isotropic MHD from the point of view of the plasma compression and the amount of the magnetic energy released across the shock. Once the slow shock forms, the downstream plasma are heated in highly anisotropic manner and a firehose-sense (P_{||}>P_{⊥}) pressure anisotropy arises. The maximum anisotropy is limited by the marginal firehose criterion, 1-(P_{||}-P_{⊥})/B(2) =0. In spite of the weakness of the shocks, the resultant reconnection rate is kept at the same level compared with that in the corresponding ordinary MHD simulations. It is also revealed that the sequential order of propagation of the slow shock and the rotational discontinuity, which appears when the guide field component exists, changes depending on the magnitude of the guide field. Especially, when no guide field exists, the rotational discontinuity degenerates with the contact discontinuity remaining at the position of the initial current sheet, while with the slow shock in the isotropic MHD. Our result implies that the slow shock does not necessarily play an important role in the energy conversion in the reconnection system and is consistent with the satellite observation in the Earth's magnetosphere.
Placidi, Luca; Seddik, Hakime; Faria, Sergio H
2009-01-01
A complete theoretical presentation of the CAFFE model (Continuum-mechanical, Anisotropic Flow model, based on an anisotropic Flow Enhancement factor) is given. The CAFFE model is an application of the theory of mixtures with continuous diversity for the case of large ice masses in which the induced anisotropy can not be neglected. The anisotropic response of the material is considered via a simple anisotropic generalization of Glen's flow law based on a scalar anisotropic enhancement factor. Such an enhancement factor depends upon the orientation mass density, that corresponds to the distribution of lattice orientations or simply to the orientation distribution function. The evolution of anisotropy is assumed to be modeled by the evolution of the orientation mass density, that is governed by the balance of mass of the present mixture with continuous diversity and explicitly depends upon four distinct effects interpreted, respectively, with grain rotation, local rigid body rotation, grain boundary migration (...
Surface and defect morphologies in anisotropic elastic and piezoelectric solids
Energy Technology Data Exchange (ETDEWEB)
Gao, Huajian; Barnett, D.M. [Stanford Univ., CA (United States)
1996-12-31
The authors investigate issues related to the equilibrium and stability of surface and line defect morphologies in both piezoelectric and anisotropic elastic solids. Following their previous efforts which established that mechanical stresses in purely elastic solids can promote instability of an initially flat surface with respect to surface roughening, they show that the (initially flat) interface between two dissimilar piezoelectric solids can be unstable when subjected to coupled electromechanical loading. Quite recent cross-sectional observations of electrodeposited thin films by Japanese and British researchers provide experimental confirmation of these predictions. The authors also investigate the occurrence of equilibrium arrangements (zero Peach-Koehler force arrangements) of line defects (dislocations) in anisotropic elastic crystals in the absence of externally applied stresses. Contrary to prevailing opinion, equilibrium arrangements of dislocations under no externally applied stresses appear to be the rule rather than the exception. The existence of such {open_quotes}zero stress arrangements{close_quotes} is fundamental to developing micromechanical models of plastically deforming solids.
Inhibitor of apoptosis proteins and apoptosis
Institute of Scientific and Technical Information of China (English)
Yunbo Wei; Tingjun Fan; Miaomiao Yu
2008-01-01
Apoptosis is a physiological cell death process that plays a critical role in development, homeostasis, and immune defense of multicellular animals. Inhibitor of apoptosis proteins (IAPs) constitute a family of proteins that possess between one and three baculovirus IAP repeats. Some of them also have a really interesting new gene finger domain, and can prevent cell death by binding and inhibiting active caspases, but are regulated by IAP antagonists. Some evidence also indicates that IAP can modulate the cell cycle and signal transduction. The three main factors, IAPs, IAP antagonists, and caspases, are involved in regulating the progress of apoptosis in many species. Many studies and assumptions have been focused on the anfractuous interactions between these three main factors to explore their real functional model in order to develop potential anticancer drugs.In this review, we describe the classification, molecular structures, and properties of IAPs and discuss the mechanisms of apoptosis. We also discuss the promising significance of clinical applications of IAPs in the diagnosis and treatment of malignancy.
Shear-free Anisotropic Cosmological Models in f(R) Gravity
Abebe, Amare; Myrzakulov, Ratbay
2015-01-01
We study a class of shear-free, homogeneous but anisotropic cosmological models with imperfect matter sources in the context of f(R) gravity. We show that the anisotropic stresses are related to the electric part of the Weyl tensor in such a way that they balance each other. We also show that within the class of orthogonal f(R) models, small perturbations of shear are damped, and that the electric part of the Weyl tensor and the anisotropic stress tensor decay with the expansion as well as the heat flux of the curvature fluid. Specializing in locally rotationally symmetric spacetimes in orthonormal frames, we examine the late-time behaviour of the de Sitter universe in $f(R)$ gravity. For the Starobinsky model of f(R), we study the evolutionary behavior of the Universe by numerically integrating the Friedmann equation, where the initial conditions for the expansion, acceleration and jerk parameters are taken from observational data.
Instabilities of collisionless current sheets revisited: the role of anisotropic heating
Muñoz, P A; Büchner, J
2015-01-01
In this work, we investigate the influence of the anisotropic heating on the spontaneous instability and evolution of thin Harris-type collisionless current sheets, embedded in antiparallel magnetic fields. In particular, we explore the influence of the macroparticle shape-function using a 2D version of the PIC code ACRONYM. We also investigate the role of the numerical collisionality due to the finite number of macroparticles in PIC codes. It is shown that it is appropriate to choose higher order shape functions of the macroparticles compared to a larger number of macroparticles per cell. This allows to estimate better the anisotropic electron heating due to the collisions of macroparticles in a PIC code. Temperature anisotropies can stabilize the tearing mode instability and trigger additional current sheet instabilities. We found a good agreement between the analytically derived threshold for the stabilization of the anisotropic tearing mode and other instabilities, either spontaneously developing or initi...
Anisotropic matching principle for the hydrodynamic expansion
Tinti, Leonardo
2016-10-01
Following the recent success of anisotropic hydrodynamics, I propose here a new, general prescription for the hydrodynamic expansion around an anisotropic background. The anisotropic distribution fixes exactly the complete energy-momentum tensor, just like the effective temperature fixes the proper energy density in the ordinary expansion around local equilibrium. This means that momentum anisotropies are already included at the leading order, allowing for large pressure anisotropies without the need of a next-to-leading-order treatment. The first moment of the Boltzmann equation (local four-momentum conservation) provides the time evolution of the proper energy density and the four-velocity. Differently from previous prescriptions, the dynamic equations for the pressure corrections are not derived from the zeroth or second moment of the Boltzmann equation, but they are taken directly from the exact evolution given by the Boltzmann equation. As known in the literature, the exact evolution of the pressure corrections involves higher moments of the Boltzmann distribution, which cannot be fixed by the anisotropic distribution alone. Neglecting the next-to-leading-order contributions corresponds to an approximation, which depends on the chosen form of the anisotropic distribution. I check the the effectiveness of the leading-order expansion around the generalized Romatschke-Stricklad distribution, comparing with the exact solution of the Boltzmann equation in the Bjorken limit with the collisional kernel treated in the relaxation-time approximation, finding an unprecedented agreement.
Anisotropic thermal conductivity of magnetic fluids
Institute of Scientific and Technical Information of China (English)
Xiaopeng Fang; Yimin Xuan; Qiang Li
2009-01-01
Considering the forces acting on the particles and the motion of the particles, this study uses a numerical simulation to investigate the three-dimensional microstructure of the magnetic fluids in the presence of an external magnetic field. A method is proposed for predicting the anisotropic thermal conductivity of magnetic fluids. By introducing an anisotropic structure parameter which characterizes the non-uniform distribution of particles suspended in the magnetic fluids, the traditional Maxwell formula is modified and extended to calculate anisotropic thermal conductivity of the magnetic fluids. The results show that in the presence of an external magnetic field the magnetic nanoparticles form chainlike clusters along the direction of the external magnetic field, which leads to the fact that the thermal conduc-tivity of the magnetic fluid along the chain direction is bigger than that along other directions. The thermal conductivity of the magnetic fluids presents an anisotropic feature. With the increase of the magnetic field strength the chainlike clusters in the magnetic fluid appear to be more obvious, so that the anisotropic feature of heat conduction in the fluids becomes more evident.
Effective medium theory for anisotropic metamaterials
Zhang, Xiujuan
2015-01-20
Materials with anisotropic material parameters can be utilized to fabricate many fascinating devices, such as hyperlenses, metasolids, and one-way waveguides. In this study, we analyze the effects of geometric anisotropy on a two-dimensional metamaterial composed of a rectangular array of elliptic cylinders and derive an effective medium theory for such a metamaterial. We find that it is possible to obtain a closed-form analytical solution for the anisotropic effective medium parameters, provided the aspect ratio of the lattice and the eccentricity of the elliptic cylinder satisfy certain conditions. The derived effective medium theory not only recovers the well-known Maxwell-Garnett results in the quasi-static regime, but is also valid beyond the long-wavelength limit, where the wavelength in the host medium is comparable to the size of the lattice so that previous anisotropic effective medium theories fail. Such an advance greatly broadens the applicable realm of the effective medium theory and introduces many possibilities in the design of structures with desired anisotropic material characteristics. A real sample of a recently theoretically proposed anisotropic medium, with a near-zero index to control the flux, is achieved using the derived effective medium theory, and control of the electromagnetic waves in the sample is clearly demonstrated.
Anisotropic nanomaterials: structure, growth, assembly, and functions.
Sajanlal, Panikkanvalappil R; Sreeprasad, Theruvakkattil S; Samal, Akshaya K; Pradeep, Thalappil
2011-01-01
Comprehensive knowledge over the shape of nanomaterials is a critical factor in designing devices with desired functions. Due to this reason, systematic efforts have been made to synthesize materials of diverse shape in the nanoscale regime. Anisotropic nanomaterials are a class of materials in which their properties are direction-dependent and more than one structural parameter is needed to describe them. Their unique and fine-tuned physical and chemical properties make them ideal candidates for devising new applications. In addition, the assembly of ordered one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) arrays of anisotropic nanoparticles brings novel properties into the resulting system, which would be entirely different from the properties of individual nanoparticles. This review presents an overview of current research in the area of anisotropic nanomaterials in general and noble metal nanoparticles in particular. We begin with an introduction to the advancements in this area followed by general aspects of the growth of anisotropic nanoparticles. Then we describe several important synthetic protocols for making anisotropic nanomaterials, followed by a summary of their assemblies, and conclude with major applications.
Anisotropic nanomaterials: structure, growth, assembly, and functions
Directory of Open Access Journals (Sweden)
Panikkanvalappil R. Sajanlal
2011-02-01
Full Text Available Comprehensive knowledge over the shape of nanomaterials is a critical factor in designing devices with desired functions. Due to this reason, systematic efforts have been made to synthesize materials of diverse shape in the nanoscale regime. Anisotropic nanomaterials are a class of materials in which their properties are direction-dependent and more than one structural parameter is needed to describe them. Their unique and fine-tuned physical and chemical properties make them ideal candidates for devising new applications. In addition, the assembly of ordered one-dimensional (1D, two-dimensional (2D, and three-dimensional (3D arrays of anisotropic nanoparticles brings novel properties into the resulting system, which would be entirely different from the properties of individual nanoparticles. This review presents an overview of current research in the area of anisotropic nanomaterials in general and noble metal nanoparticles in particular. We begin with an introduction to the advancements in this area followed by general aspects of the growth of anisotropic nanoparticles. Then we describe several important synthetic protocols for making anisotropic nanomaterials, followed by a summary of their assemblies, and conclude with major applications.
A cortical locus for anisotropic overlay suppression of stimuli presented at fixation.
Hansen, Bruce C; Richard, Bruno; Andres, Kristin; Johnson, Aaron P; Thompson, Benjamin; Essock, Edward A
2015-01-01
Human contrast sensitivity for narrowband Gabor targets is suppressed when superimposed on narrowband masks of the same spatial frequency and orientation (referred to as overlay suppression), with suppression being broadly tuned to orientation and spatial frequency. Numerous behavioral and neurophysiological experiments have suggested that overlay suppression originates from the initial lateral geniculate nucleus (LGN) inputs to V1, which is consistent with the broad tuning typically reported for overlay suppression. However, recent reports have shown narrowly tuned anisotropic overlay suppression when narrowband targets are masked by broadband noise. Consequently, researchers have argued for an additional form of overlay suppression that involves cortical contrast gain control processes. The current study sought to further explore this notion behaviorally using narrowband and broadband masks, along with a computational neural simulation of the hypothesized underlying gain control processes in cortex. Additionally, we employed transcranial direct current stimulation (tDCS) in order to test whether cortical processes are involved in driving narrowly tuned anisotropic suppression. The behavioral results yielded anisotropic overlay suppression for both broadband and narrowband masks and could be replicated with our computational neural simulation of anisotropic gain control. Further, the anisotropic form of overlay suppression could be directly modulated by tDCS, which would not be expected if the suppression was primarily subcortical in origin. Altogether, the results of the current study provide further evidence in support of an additional overlay suppression process that originates in cortex and show that this form of suppression is also observable with narrowband masks.
Phenomenological predictions of 3+1d anisotropic hydrodynamics
Nopoush, Mohammad; Ryblewski, Radoslaw
2016-01-01
We make phenomenological predictions for particle spectra and elliptic flow in heavy-ion collisions using 3+1d anisotropic hydrodynamics (aHydro) including the effects of both shear and bulk viscosities. The dynamical equations necessary are derived by taking moments of the Boltzmann equation allowing for three distinct (diagonal) momentum-space anisotropy parameters. The formulation is based on relaxation-time approximation for the collisional kernel and a lattice-QCD-based equation of state. Evolving the system to late times, we calculate particle production using THERMINATOR 2, modified to account for an ellipsoidal distribution function. We obtain particle spectra for different particle species such as pions, kaons, and protons, and elliptic flow $v_2$ as a function of centrality, transverse momentum, and rapidity. In our model, we have four free parameters, i.e. freeze-out temperature, initial central energy density, initial momentum-space anisotropies, and shear viscosity to entropy density ratio. Using...
Gravitational stresses in anisotropic rock masses
Amadei, B.; Savage, W.Z.; Swolfs, H.S.
1987-01-01
This paper presents closed-form solutions for the stress field induced by gravity in anisotropic rock masses. These rocks are assumed to be laterally restrained and are modelled as a homogeneous, orthotropic or transversely isotropic, linearly elastic material. The analysis, constrained by the thermodynamic requirement that strain energy be positive definite, gives the following important result: inclusion of anisotropy broadens the range of permissible values of gravity-induced horizontal stresses. In fact, for some ranges of anisotropic rock properties, it is thermodynamically admissible for gravity-induced horizontal stresses to exceed the vertical stress component; this is not possible for the classical isotropic solution. Specific examples are presented to explore the nature of the gravity-induced stress field in anisotropic rocks and its dependence on the type, degree and orientation of anisotropy with respect to the horizontal ground surface. ?? 1987.
Generalized Fractional Derivative Anisotropic Viscoelastic Characterization
Directory of Open Access Journals (Sweden)
Harry H. Hilton
2012-01-01
Full Text Available Isotropic linear and nonlinear fractional derivative constitutive relations are formulated and examined in terms of many parameter generalized Kelvin models and are analytically extended to cover general anisotropic homogeneous or non-homogeneous as well as functionally graded viscoelastic material behavior. Equivalent integral constitutive relations, which are computationally more powerful, are derived from fractional differential ones and the associated anisotropic temperature-moisture-degree-of-cure shift functions and reduced times are established. Approximate Fourier transform inversions for fractional derivative relations are formulated and their accuracy is evaluated. The efficacy of integer and fractional derivative constitutive relations is compared and the preferential use of either characterization in analyzing isotropic and anisotropic real materials must be examined on a case-by-case basis. Approximate protocols for curve fitting analytical fractional derivative results to experimental data are formulated and evaluated.
Anisotropic non-gaussianity with noncommutative spacetime
Energy Technology Data Exchange (ETDEWEB)
Nautiyal, Akhilesh
2014-01-20
We study single field inflation in noncommutative spacetime and compute two-point and three-point correlation functions for the curvature perturbation. We find that both power spectrum and bispectrum for comoving curvature perturbation are statistically anisotropic and the bispectrum is also modified by a phase factor depending upon the noncommutative parameters. The non-linearity parameter f{sub NL} is small for small statistical anisotropic corrections to the bispectrum coming from the noncommutative geometry and is consistent with the recent PLANCK bounds. There is a scale dependence of f{sub NL} due to the noncommutative spacetime which is different from the standard single field inflation models and statistically anisotropic vector field inflation models. Deviations from statistical isotropy of CMB, observed by PLANCK can tightly constraint the effects due to noncommutative geometry on power spectrum and bispectrum.
Leith diffusion model for homogeneous anisotropic turbulence
Rubinstein, Robert; Clark, Timothy; Kurien, Susan
2016-11-01
A new spectral closure model for homogeneous anisotropic turbulence is proposed. The systematic development begins by closing the third-order correlation describing nonlinear interactions by an anisotropic generalization of the Leith diffusion model for isotropic turbulence. The correlation tensor is then decomposed into a tensorially isotropic part, or directional anisotropy, and a trace-free remainder, or polarization anisotropy. The directional and polarization components are then decomposed using irreducible representations of the SO(3) symmetry group. Under the ansatz that the decomposition is truncated at quadratic order, evolution equations are derived for the directional and polarization pieces of the correlation tensor. Numerical simulation of the model equations for a freely decaying anisotropic flow illustrate the non-trivial effects of spectral dependencies on the different return-to-isotropy rates of the directional and polarization contributions.
Theory of Compton scattering by anisotropic electrons
Poutanen, Juri
2010-01-01
Compton scattering plays an important role in various astrophysical objects such as accreting black holes and neutron stars, pulsars, and relativistic jets, clusters of galaxies as well as the early Universe. In most of the calculations it is assumed that the electrons have isotropic angular distribution in some frame. However, there are situations where the anisotropy may be significant due to the bulk motions, or anisotropic cooling by synchrotron radiation, or anisotropic source of seed soft photons. We develop here an analytical theory of Compton scattering by anisotropic distribution of electrons that can simplify significantly the calculations. Assuming that the electron angular distribution can be represented by a second order polynomial over cosine of some angle (dipole and quadrupole anisotropy), we integrate the exact Klein-Nishina cross-section over the angles. Exact analytical and approximate formulae valid for any photon and electron energies are derived for the redistribution functions describin...
Anisotropic inflation in the Finsler spacetime
Energy Technology Data Exchange (ETDEWEB)
Li, Xin [Chongqing University, Department of Physics, Chongqing (China); Institute of Theoretical Physics, Chinese Academy of Sciences, State Key Laboratory of Theoretical Physics, Beijing (China); Wang, Sai [Institute of Theoretical Physics, Chinese Academy of Sciences, State Key Laboratory of Theoretical Physics, Beijing (China); Chang, Zhe [Institute of Theoretical Physics, Chinese Academy of Sciences, State Key Laboratory of Theoretical Physics, Beijing (China); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China)
2015-06-15
We suggest the universe is Finslerian in the stage of inflation. The Finslerian background spacetime breaks rotational symmetry and induces parity violation. The primordial power spectrum is given for the quantum fluctuation of the inflation field. It depends not only on the magnitude of the wavenumber but also on the preferred direction. We derive the gravitational field equations in the perturbed Finslerian background spacetime, and we obtain a conserved quantity outside the Hubble horizon. The angular correlation coefficients are presented in our anisotropic inflation model. The parity violation feature of Finslerian background spacetime requires that the anisotropic effect only appears in the angular correlation coefficients if l' = l + 1. The numerical results of the angular correlation coefficients are given describing the anisotropic effect. (orig.)
Anisotropic Hanle line shape via magnetothermoelectric phenomena
Das, K. S.; Dejene, F. K.; van Wees, B. J.; Vera-Marun, I. J.
2016-11-01
We observe anisotropic Hanle line shape with unequal in-plane and out-of-plane nonlocal signals for spin precession measurements carried out on lateral metallic spin valves with transparent interfaces. The conventional interpretation for this anisotropy corresponds to unequal spin relaxation times for in-plane and out-of-plane spin orientations as for the case of two-dimensional materials like graphene, but it is unexpected in a polycrystalline metallic channel. Systematic measurements as a function of temperature and channel length, combined with both analytical and numerical thermoelectric transport models, demonstrate that the anisotropy in the Hanle line shape is magnetothermal in origin, caused by the anisotropic modulation of the Peltier and Seebeck coefficients of the ferromagnetic electrodes. Our results call for the consideration of such magnetothermoelectric effects in the study of anisotropic spin relaxation.
Anisotropic selection in cellular genetic algorithms
Simoncini, David; Collard, Philippe; Clergue, Manuel
2008-01-01
In this paper we introduce a new selection scheme in cellular genetic algorithms (cGAs). Anisotropic Selection (AS) promotes diversity and allows accurate control of the selective pressure. First we compare this new scheme with the classical rectangular grid shapes solution according to the selective pressure: we can obtain the same takeover time with the two techniques although the spreading of the best individual is different. We then give experimental results that show to what extent AS promotes the emergence of niches that support low coupling and high cohesion. Finally, using a cGA with anisotropic selection on a Quadratic Assignment Problem we show the existence of an anisotropic optimal value for which the best average performance is observed. Further work will focus on the selective pressure self-adjustment ability provided by this new selection scheme.
Micromechanics and dislocation theory in anisotropic elasticity
Lazar, Markus
2016-01-01
In this work, dislocation master-equations valid for anisotropic materials are derived in terms of kernel functions using the framework of micromechanics. The second derivative of the anisotropic Green tensor is calculated in the sense of generalized functions and decomposed into a sum of a $1/R^3$-term plus a Dirac $\\delta$-term. The first term is the so-called "Barnett-term" and the latter is important for the definition of the Green tensor as fundamental solution of the Navier equation. In addition, all dislocation master-equations are specified for Somigliana dislocations with application to 3D crack modeling. Also the interior Eshelby tensor for a spherical inclusion in an anisotropic material is derived as line integral over the unit circle.
Quasiparticle anisotropic hydrodynamics for central collisions
Alqahtani, Mubarak; Strickland, Michael
2016-01-01
We use quasiparticle anisotropic hydrodynamics to study an azimuthally-symmetric boost-invariant quark-gluon plasma including the effects of both shear and bulk viscosities. In quasiparticle anisotropic hydrodynamics, a single finite-temperature quasiparticle mass is introduced and fit to the lattice data in order to implement a realistic equation of state. We compare results obtained using the quasiparticle method with the standard method of imposing the equation of state in anisotropic hydrodynamics and viscous hydrodynamics. Using these three methods, we extract the primordial particle spectra, total number of charged particles, and average transverse momentum for various values of the shear viscosity to entropy density ratio eta/s. We find that the three methods agree well for small shear viscosity to entropy density ratio, eta/s, but differ at large eta/s. We find, in particular, that when using standard viscous hydrodynamics, the bulk-viscous correction can drive the primordial particle spectra negative...
Obtuse triangle suppression in anisotropic meshes
Sun, Feng
2011-12-01
Anisotropic triangle meshes are used for efficient approximation of surfaces and flow data in finite element analysis, and in these applications it is desirable to have as few obtuse triangles as possible to reduce the discretization error. We present a variational approach to suppressing obtuse triangles in anisotropic meshes. Specifically, we introduce a hexagonal Minkowski metric, which is sensitive to triangle orientation, to give a new formulation of the centroidal Voronoi tessellation (CVT) method. Furthermore, we prove several relevant properties of the CVT method with the newly introduced metric. Experiments show that our algorithm produces anisotropic meshes with much fewer obtuse triangles than using existing methods while maintaining mesh anisotropy. © 2011 Elsevier B.V. All rights reserved.
Constraining the Anisotropic Expansion of Universe
Cai, Rong-Gen; Tang, Bo; Tuo, Zhong-Liang
2013-01-01
We study the possibly existing anisotropy in the accelerating expansion Universe with the Union2 Type Ia supernovae data and Gamma-ray burst data. We construct a direction-dependent dark energy model and constrain the anisotropy direction and strength of modulation. We find that the maximum anisotropic deviation direction is $(l,\\,b)=(126^{\\circ},\\,13^{\\circ})$ (or equivalently $(l,\\,b)=(306^{\\circ},\\,-13^{\\circ})$), and the anisotropy level is $g_0=0.030_{+0.010}^{-0.030}$ (obtained using Union2 data, at $1\\sigma$ confidence level). Our results do not show strong evidence for the anisotropic dark energy model. We also discuss potential methods that may distinguish the peculiar velocity field from the anisotropic dark energy model.
DNA fragmentation in apoptosis
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Cleavage of chromosomal DNA into oligonucleosomal size fragments is an integral part of apoptosis. Elegant biochemical work identified the DNA fragmentation factor (DFF) as a major apoptotic endonuclease for DNA fragmentation in vitro. Genetic studies in mice support the importance of DFF in DNA fragmentation and possibly in apoptosis in vivo. Recent work also suggests the existence of additional endonucleases for DNA degradation. Understanding the roles of individual endonucleases in apoptosis, and how they might coordinate to degrade DNA in different tissues during normal development and homeostasis, as well as in various diseased states, will be a major research focus in the near future.
Raman Tensor Formalism for Optically Anisotropic Crystals.
Kranert, Christian; Sturm, Chris; Schmidt-Grund, Rüdiger; Grundmann, Marius
2016-03-25
We present a formalism for calculating the Raman scattering intensity dependent on the polarization configuration for optically anisotropic crystals. It can be applied to crystals of arbitrary orientation and crystal symmetry measured in normal incidence backscattering geometry. The classical Raman tensor formalism cannot be used for optically anisotropic materials due to birefringence causing the polarization within the crystal to be depth dependent. We show that in the limit of averaging over a sufficiently large scattering depth, the observed Raman intensities converge and can be described by an effective Raman tensor given here. Full agreement with experimental results for uniaxial and biaxial crystals is demonstrated.
Anisotropic Heisenberg model in thin film geometry
Energy Technology Data Exchange (ETDEWEB)
Akıncı, Ümit
2014-01-01
The effect of the anisotropy in the exchange interaction on the phase diagrams and magnetization behavior of the Heisenberg thin film has been investigated with effective field formulation in a two spin cluster using the decoupling approximation. Phase diagrams and magnetization behaviors have been obtained for several different cases, by grouping the systems in accordance with, whether the surfaces/interior of the film has anisotropic exchange interaction or not. - Highlights: • Phase diagrams of the anisotropic Heisenberg model on the thin film obtained • Dependence of the critical properties on the film thickness obtained • Effect of the anisotropy on the magnetic properties obtained.
Enhanced-transmission metamaterials as anisotropic plates
Baida, F. I.; Boutria, M.; Oussaid, R.; van Labeke, D.
2011-07-01
We present an original design of anisotropic metamaterial plates exhibiting extraordinary transmission through perfectly conductor metallic screens perforated by a subwavelength double-pattern rectangular aperture array. The polarization properties of the fundamental guided mode inside the apertures are at the origin of the anisotropy. The metal thickness is a key parameter that is adjusted in order to get the desired value of the phase difference between the two transversal electromagnetic field components. As an example, we treat the case of a half-wave plate having 92% transmission coefficient. Such a study can be easily extended to design anisotropic plates operating in terahertz or microwave domains.
One-Dimensional Anisotropic Band Gap Structure
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The band gap structure of one-dimensional anisotropic photonic crystal has been studied by means of the transfer matrix formalism. From the analytic expressions and numeric calculations we see some general characteristics of the band gap structure of anisotropic photonic crystals, each band separates into two branches and the two branches react to polarization sensitively. In the practical case of oblique incidence, gaps move towards high frequency when the angle of incidence increases. Under some special conditions, the two branches become degenerate again.
Anisotropic Gold Nanocrystals:. Synthesis and Characterization
Stiufiuc, R.; Toderas, F.; Iosin, M.; Stiufiuc, G.
In this letter we report on successful preparation and characterization of anisotropic gold nanocrystals bio-synthesized by reduction of aqueous chloroaurate ions in pelargonium plant extract. The nanocrystals have been characterized by means of Transmission Electron Microscopy (TEM), UV-VIS absorption spectroscopy and tapping mode atomic force microscopy (TM-AFM). Using these investigation techniques, the successful formation of anisotropic single nanocrystals with the preferential growth direction along the gold (111) plane has been confirmed. The high detail phase images could give us an explanation concerning the growth mechanism of the nanocrystals.
Anisotropic strange star with de Sitter spacetime
Kalam, Mehedi; Rahaman, Farook; Ray, Saibal; Hossein, Sk. Monowar; Karar, Indrani; Naskar, Jayanta
2012-12-01
Stars can be treated as self-gravitating fluid. Krori and Barua (J. Phys. A., Math. Gen. 8:508, 1975) gave an analytical solution to that kind of fluids. In this connection, we propose a de Sitter model for an anisotropic strange star with the Krori-Barua spacetime. We incorporate the existence of the cosmological constant on a small scale to study the structure of anisotropic strange stars and come to the conclusion that this doping is very well compatible with the well-known physical features of strange stars.
Relativistic Solutions of Anisotropic Compact Objects
Paul, Bikash Chandra
2016-01-01
We present a class of new relativistic solutions with anisotropic fluid for compact stars in hydrostatic equilibrium. The interior space-time geometry considered here for compact objects are described by parameters namely, $\\lambda$, $k$, $A$, $R$ and $n$. The values of the geometrical parameters are determined here for obtaining a class of physically viable stellar models. The energy-density, radial pressure and tangential pressure are finite and positive inside the anisotropic stars. Considering some stars of known mass we present stellar models which describe compact astrophysical objects with nuclear density.
Anisotropic nanomaterials preparation, properties, and applications
Li, Quan
2015-01-01
In this book anisotropic one-dimensional and two-dimensional nanoscale building blocks and their assembly into fascinating and qualitatively new functional structures embracing both hard and soft components are explained. Contributions from leading experts regarding important aspects like synthesis, assembly, properties and applications of the above materials are compiled into a reference book. The anisotropy, i.e. the direction-dependent physical properties, of materials is fascinating and elegant and has sparked the quest for anisotropic materials with useful properties. With such a curiosi
Apoptosis in Pneumovirus Infection
Directory of Open Access Journals (Sweden)
Reinout A. Bem
2013-01-01
Full Text Available Pneumovirus infections cause a wide spectrum of respiratory disease in humans and animals. The airway epithelium is the major site of pneumovirus replication. Apoptosis or regulated cell death, may contribute to the host anti-viral response by limiting viral replication. However, apoptosis of lung epithelial cells may also exacerbate lung injury, depending on the extent, the timing and specific location in the lungs. Differential apoptotic responses of epithelial cells versus innate immune cells (e.g., neutrophils, macrophages during pneumovirus infection can further contribute to the complex and delicate balance between host defense and disease pathogenesis. The purpose of this manuscript is to give an overview of the role of apoptosis in pneumovirus infection. We will examine clinical and experimental data concerning the various pro-apoptotic stimuli and the roles of apoptotic epithelial and innate immune cells during pneumovirus disease. Finally, we will discuss potential therapeutic interventions targeting apoptosis in the lungs.
Metformin induces apoptosis of pancreatic cancer cells
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
AIM: To assess the role and mechanism of mefformin in inducing apoptosis of pancreatic cancer cells. METHODS: The human pancreatic cancer cell lines ASPC-1, BxPc-3, PANC-1 and SW1990 were exposed to mefformin. The inhibition of cell proliferation and colony formation via apoptosis induction and S phase arrest in pancreatic cancer cell lines of mefformin was tested.RESULTS: In each pancreatic cancer cell line tested, metformin inhibited cell proliferation in a dose dependent manner in MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assays). Flow cytometric analysis showed that metformin reduced the number of cells in G1 and increased the percentage of cells in S phase as well as the apoptotic fraction. Enzymelinked immunosorbent assay (EUSA) showed that metformin induced apaptosis in all pancreatic cancer cell lines. In Western blot studies, metformin induced oly-ADP-ribose polymerase(PARP) cleavage (an indicator of aspase activation) in all pancreatic cancer cell lines. The general caspase inhibitor (VAD-fmk) completely abolished metformin-induced PARP cleavage and apoptosis in ASPC-1 BxPc-3 and PANC-1, the caspase-8 specific inhibitor (IETD-fmk) and the caspase-9 specific inhibitor (LEHD-fmk) only partially abrogated metformin-induced apoptosis and PARP cleavage in BxPc-3 and PANC-1 cells. We also observed that metformin treatment ramatically reduced epidermal growth factor receptor (EGFR) and phosphorylated mitogen activated protein kinase (P-MAPK) in both a time- and dose-dependent manner in all cell lines tested.CONCLUSION: Metformin significantly inhibits cell proliferation and apoptosis in all pancreatic cell lines. And the metformin-induced apoptosis is associated with PARP leavage, activation of caspase-3, -8, and -9 in a time- and dose-dependent manner. Hence, both caspase-8 and -9-initiated apoptotic signaling pathways contribute to metforrnin-induced apoptosis in pancreatic cell lines.
Failure Analysis of Warm Stamping of Magnesium Alloy Sheet Based on an Anisotropic Damage Model
Zhao, P. J.; Chen, Z. H.; Dong, C. F.
2014-11-01
Based on the frame work of continuum damage mechanics, a research work of anisotropic damage evolution in warm stamping process of magnesium alloy sheets has been carried out by means of a combined experimental-numerical method. The aim was to predict formability of warm stamping of AZ31 Mg alloy sheets by taking the thermal and damage effects into account. In the presented work, a temperature-dependent anisotropic yield function suitable for cold rolling sheet metals together with an anisotropic damage model was implemented into the a VUMAT subroutine for ABAQUS/EXPLICIT. The evolution of internal damage in the form of void growth and coalescence in AZ31 Mg alloy sheet was observed by means of scanning electron microscopy (SEM). Moreover, a coupled thermo-mechanical simulation of the stamping process was performed using the implemented code at different temperatures. The parameters employed in the simulation were determined by the standard tensile tests and algebraic manipulation. The overall anisotropic damage process from crack initiation to final propagation in local area of blank was simulated. Numerical results show that the prediction of the site of crack initiation and the orientation of crack propagation are consistent with the data observed in warm stamping experiments.
Observational signatures of anisotropic inflationary models
Ohashi, Junko; Tsujikawa, Shinji
2013-01-01
We study observational signatures of two classes of anisotropic inflationary models in which an inflaton field couples to (i) a vector kinetic term F_{mu nu}F^{mu nu} and (ii) a two-form kinetic term H_{mu nu lambda}H^{mu nu lambda}. We compute the corrections from the anisotropic sources to the power spectrum of gravitational waves as well as the two-point cross correlation between scalar and tensor perturbations. The signs of the anisotropic parameter g_* are different depending on the vector and the two-form models, but the statistical anisotropies generally lead to a suppressed tensor-to-scalar ratio r and a smaller scalar spectral index n_s in both models. In the light of the recent Planck bounds of n_s and r, we place observational constraints on several different inflaton potentials such as those in chaotic and natural inflation in the presence of anisotropic interactions. In the two-form model we also find that there is no cross correlation between scalar and tensor perturbations, while in the vector ...
Spin Wave Theory of Strongly Anisotropic Magnets
DEFF Research Database (Denmark)
Lindgård, Per-Anker
1977-01-01
A strong anisotropy gives rise to a non-spherical precession of the spins with different amplitudes in the x and y directions. The highly anharmonic exchange interaction thereby becomes effectively anisotropic. The possibility of detecting a genuine two-ion anisotropy is discussed, and comments a...
Orphan-Free Anisotropic Voronoi Diagrams
Canas, Guillermo D
2011-01-01
We describe conditions under which an appropriately-defined anisotropic Voronoi diagram of a set of sites in Euclidean space is guaranteed to be composed of connected cells in any number of dimensions. These conditions are natural for problems in optimization and approximation, and algorithms already exist to produce sets of sites that satisfy them.
Anisotropic Interactions between Cold Rydberg Atoms
2015-09-28
AFRL-AFOSR-CL-TR-2015-0002 Anisotropic interactions between cold Rydberg atoms Luis Marcassa INSTITUTO DE FISICA DE SAO CARLOS Final Report 09/28...problem with the report +551633739806 Organization / Institution name Instituto de Fisica de Sao Carlos Grant/Contract Title The full title of the
Frontiers in Anisotropic Shock-Wave Modeling
2012-02-01
contact info: Tel.: +44 07840355383, Fax: +44 (0) 1234 758217. Studies of anisotropic materials and the discovery of various novel and unexpected phenomena...19 Figure 4. The Kevlar ...Epoxy IFPT simulated and experimental back surface velocities for 572, 788, and 1015 m/s. The experimental data Kevlar /Epoxy materials recovered after
Surface instabilities during straining of anisotropic materials
DEFF Research Database (Denmark)
Legarth, Brian Nyvang; Richelsen, Ann Bettina
2006-01-01
The development of instabilities in traction-free surfaces is investigated numerically using a unit cell model. Full finite strain analyses are conducted using isotropic as well as anisotropic yield criteria and both plane strain tension and compression are considered. In the load range of tension...
A discrete anisotropic model for Scheibe aggregates
Directory of Open Access Journals (Sweden)
O. Bang
1991-05-01
Full Text Available A discrete anisotropic nonlinear model for the dynamics of Scheibe aggregates is investigated. The collapse of the collective excitations found by Möbius and Kuhn is described as a shrinking ring wave, which is eventually absorbed by an acceptor molecule. An optimal acceptor loss is found.
Anisotropic shrinkage characteristics of tape cast alumina
Patwardhan, Jaideep Suresh
Dimensional control during sintering is a major issue in ceramics processing to avoid high post-sintering costs associated with machining of the fired ceramic part to desired tolerances and dimensions. Ceramic forming processes such as tape casting, injection molding, and extrusion involve shear of anisotropic particles resulting in preferential alignment of the particles in the green body. This preferential alignment causes directionality in mechanical, electrical, optical, and magnetic properties and most importantly warpage or distortion during sintering. A large effort has been devoted to synthesizing ceramic green bodies with minimal density gradients and uniform packing and modeling the sintering behavior evolution but little effort has been devoted to characterizing orientation of particles and the effect of preferential alignment on sintering shrinkage anisotropy. A systematic study was initiated to study the effect of processing variables such as shear rate, solids loading, temperature, and binder content on aqueous tape cast alumina. Three different alumina systems: A16-SG, Baikowski RC-UFX DBM and RC-LS DBM were investigated. Aqueous tapes of high solids loading alumina (56 vol. %) were tape cast at various speeds and thicknesses and assuming plane Couette flow a shear rate regime of 21--270 s-1 was investigated. Higher shear rates and high solids loading resulted in higher in-plane anisotropy whereas the anisotropy in the thickness direction was higher for low solids loading systems. The anisotropy was found to be fairly constant above a certain critical shear rate (˜100 s-1) irrespective of the temperature and the solids loading and this correlated with the viscosity-shear rate relationship of the cast slips. The higher shrinkage anisotropy in the thickness direction for the low solids loading systems (35 and 45 vol. %) was attributed to the higher amount of organics in the slip required to sustain the suitable viscosity for tape casting and
Identification of genes responsive to apoptosis in HL-60 cells
Institute of Scientific and Technical Information of China (English)
Wei JIN; Le-feng QU; Ping MIN; Shan CHEN; Hong LI; He LU; Yong-tai HOU
2004-01-01
AIM: To identify genes responsive to apoptosis in HL-60 cells treated by homoharringtonine. METHODS: cDNA microarray technology was used to detect gene expression and the result of microarrays for genes (TIEG and VDUP1) was confirmed by Northern analysis. RESULTS: Seventy-five individual mRNAs whose mass changed significantly were identified. Among these genes (25 were up-regulated and 50 were down-regulated), most are known related to oncogenes and tumor suppressor. Some genes were involved in apoptosis signaling pathways.CONCLUSION: TGFβ and TNF apoptosis signaling pathways were initiated during apoptosis in HL-60 cells.TIEG and VDUP1 play important roles in mediating apoptosis.
Views on the Anisotropic Nature of Ilva Valley Region
Directory of Open Access Journals (Sweden)
GABRIELA-ALINA MUREŞAN
2012-01-01
Full Text Available There are two concepts important for the authors of this article: anisotropic region and anisotropic space. Anisotropic region is defined by A. Dauphiné, the geographer (-mathematician, as a territorial unit whose structure results from the organisation of space along one or more axes. From the point of view of a territorial system, this type of region has some characteristics which differentiate it both from the homogeneous region and from the polarised one. These specificities have been analysed for Ilva Valley. The region of Ilva Valley is formed along the morphological axis represented by the Ilva River. The aim is to identify these specificities or their absence within this region. In this way we can determine whether this region is an anisotropic one or just an anisotropic space, namely whether it can be considered as evolving towards an anisotropic region, not yet complying with all characteristics of anisotropic regions.
Photothermal method for absorption measurements in anisotropic crystals
Stubenvoll, M.; Schäfer, B.; Mann, K.; Novak, O.
2016-02-01
A measurement system for quantitative determination of both surface and bulk contributions to the photo-thermal absorption has been extended to anisotropic optical media. It bases upon a highly sensitive Hartmann-Shack wavefront sensor, accomplishing precise on-line monitoring of wavefront deformations of a collimated test beam transmitted perpendicularly through the laser-irradiated side of a cuboid sample. Caused by the temperature dependence of the refractive index as well as thermal expansion, the initially plane wavefront of the test beam is distorted. Sign and magnitude depend on index change and expansion. By comparison with thermal theory, a calibration of the measurement is possible, yielding a quantitative absolute measure of bulk and surface absorption losses from the transient wavefront distortion. Results for KTP and BBO single crystals are presented.
LYMPHOCYTE APOPTOSIS IN PSORIASIS
Directory of Open Access Journals (Sweden)
О. M. Kapuler
2006-01-01
Full Text Available Abstract. Forty-two patients with progressive vulgar psoriasis (PASI = 19.7 ± 1.5 and 40 healthy volunteers were under investigation. Psoriatic patients were characterized by increased number of CD4+ CD95+ peripheral blood T lymphocytes, which correlates with clinical psoriatic score, and by increased levels of soluble Fas (sFas in serum, as compared to controls (resp., 1868.1 ± 186.8 pg/ml vs. 1281.4 ± 142.5 pg/ml, PLSD = 0.019. The levels of spontaneous lymphocyte apoptosis and anti-Fas (Mab-induced apoptosis in psoriatic patients did not differ from the controls. However, apoptosis induced by “oxidative stress” (50 M Н202, 4 hrs was depressed in the patients. Moreover, a simultaneous assessment of cell cycle structure (metachromatic staining with Acridine Orange, apoptosis and Fas receptor expression (AnnV-FITC/antiFas mAbs-PE staining following a short-term mitogenic stimulation (PHA-P, 5 µg/ml, 24 hrs were performed. We found no marked differences in mitogenic reactivity, activation-induced apoptosis, and activation-induced Fas receptor expression when studying lymphocytes from healthy donors and psoriatic patients. However, PHA-activated lymphocytes from psoriatic patients displayed a significantly decreased ratio of AnnV+CD95+ to the total AnnV+ subpopulation, thus suggesting a decreased role of Fas-dependent mechanisms of apoptosis during the cell activation. The data obtained confirm a view, that an abnormal lymphocyte “apoptotic reactivity”, which plays a crucial role in the mechanisms of autoimmunity, may also of importance in the pathogenesis of psoriasis.
Apoptosis - Methods and Protocols
Directory of Open Access Journals (Sweden)
CarloAlberto Redi
2010-03-01
Full Text Available Apoptosis - Methods and ProtocolsSecond edition, 2009; Peter Erhardt and Ambrus Toth (Eds; Springer Protocols - Methods in molecular biology, vol. 559; Humana press, Totowa, New Jersey (USA; Pages: 400; €88.35; ISBN: 978-1-60327-016-8The editors rightly begin the preface telling us that: “The ability to detect and quantify apoptosis, to understand its biochemistry and to identify its regulatory genes and proteins is crucial to biomedical research”. Nowadays this is a grounding concept of biology and medicine. What is particularly remarkable...
The biochemistry of apoptosis.
Hengartner, M O
2000-10-12
Apoptosis--the regulated destruction of a cell--is a complicated process. The decision to die cannot be taken lightly, and the activity of many genes influence a cell's likelihood of activating its self-destruction programme. Once the decision is taken, proper execution of the apoptotic programme requires the coordinated activation and execution of multiple subprogrammes. Here I review the basic components of the death machinery, describe how they interact to regulate apoptosis in a coordinated manner, and discuss the main pathways that are used to activate cell death.
Designing novel anisotropic lenses with transformation optics
Jiang, Wei Xiang; Bao, Di; Cui, Tie Jun
2016-04-01
Transformation optics (TO), based on the formally invariant property of Maxwell’s equations, has provided a powerful strategy to design anisotropic or nearly-isotropic devices, in both time-varied and static fields. In this paper, we present and investigate the negative refraction or reflection phenomena by positive-index anisotropic materials based on transformation-optics design. First, we propose and design an inhomogeneous transformed planar lens, in which we will show the negative-refraction-like properties of transformation media. Secondly, we present a homogeneous transformed lens based on linear spatial transformation, in which we will reveal the negative-reflection properties of positive transformation media. Both transformed lenses have unusual properties which are different from those in natural materials.
Observation of an Anisotropic Wigner Crystal
Liu, Yang; Hasdemir, S.; Pfeiffer, L. N.; West, K. W.; Baldwin, K. W.; Shayegan, M.
2016-09-01
We report a new correlated phase of two-dimensional charged carriers in high magnetic fields, manifested by an anisotropic insulating behavior at low temperatures. It appears in a large range of low Landau level fillings 1 /3 ≲ν ≲2 /3 in hole systems confined to wide GaAs quantum wells when the sample is tilted in magnetic field to an intermediate angle. The parallel field component (B∥) leads to a crossing of the lowest two Landau levels, and an elongated hole wave function in the direction of B∥. Under these conditions, the in-plane resistance exhibits an insulating behavior, with the resistance along B∥ about 10 times smaller than the resistance perpendicular to B∥. We interpret this anisotropic insulating phase as a two-component, striped Wigner crystal.
Anisotropic Spin Splitting in Step Quantum Wells
Institute of Scientific and Technical Information of China (English)
HAO Ya-Fei; CHEN Yong-Hai; HAO Guo-Dong; WANG Zhan-Guo
2009-01-01
By the method of finite difference,the anisotropic spin splitting of the Alx Ga1-x As/GaAs/Aly Ga1-y As/Alx Ga1-x As step quantum wells (QWs) are theoretically investigated considering the interplay of the bulk inversion asymmetry and structure inversion asymmetry induced by step quantum well structure and external electric field.We demonstrate that the anisotropy of the total spin splitting can be controlled by the shape of the QWs and the external electric field.The interface related Rashba effect plays an important effect on the anisotropic spin splitting by influencing the magnitude of the spin splitting and the direction of electron spin.The Rashba spin splitting presents in the step quantum wells due to the interface related Rashba effect even without external electric field or magnetic field.
Bond diluted anisotropic quantum Heisenberg model
Energy Technology Data Exchange (ETDEWEB)
Akıncı, Ümit, E-mail: umit.akinci@deu.edu.tr
2013-10-15
Effects of the bond dilution on the critical temperatures, phase diagrams and the magnetization behaviors of the isotropic and anisotropic quantum Heisenberg model have been investigated in detail. For the isotropic case, bond percolation threshold values have been determined for several numbers of two (2D) and three (3D) dimensional lattices. In order to investigate the effect of the anisotropy in the exchange interaction on the results obtained for the isotropic model, a detailed investigation has been made on a honeycomb lattice. Some interesting results, such as second order reentrant phenomena in the phase diagrams have been found. - Highlights: • Anisotropic quantum Heisenberg model with bond dilution investigated. • Bond percolation threshold values given for 2D and 3D lattices in isotropic case. • Phase diagrams and ground state magnetizations investigated in detail. • Variation of the bond percolation threshold values with anisotropy determined.
Rainbow metric from quantum gravity: anisotropic cosmology
Assanioussi, Mehdi
2016-01-01
In this paper we present a construction of effective cosmological models which describe the propagation of a massive quantum scalar field on a quantum anisotropic cosmological spacetime. Each obtained effective model is represented by a rainbow metric in which particles of distinct momenta propagate on different classical geometries. Our analysis shows that upon certain assumptions and conditions on the parameters determining such anisotropic models, we surprisingly obtain a unique deformation parameter $\\beta$ in the modified dispersion relation of the modes. Hence inducing an isotropic deformation despite the general starting considerations. We then ensure the recovery of the dispersion relation realized in the isotropic case, studied in [arXiv:1412.6000], when some proper symmetry constraints are imposed, and we estimate the value of the deformation parameter for this case in loop quantum cosmology context.
Rainbow metric from quantum gravity: Anisotropic cosmology
Assanioussi, Mehdi; Dapor, Andrea
2017-03-01
In this paper we present a construction of effective cosmological models which describe the propagation of a massive quantum scalar field on a quantum anisotropic cosmological spacetime. Each obtained effective model is represented by a rainbow metric in which particles of distinct momenta propagate on different classical geometries. Our analysis shows that upon certain assumptions and conditions on the parameters determining such anisotropic models, we surprisingly obtain a unique deformation parameter β in the modified dispersion relation of the modes, hence, inducing an isotropic deformation despite the general starting considerations. We then ensure the recovery of the dispersion relation realized in the isotropic case, studied in [M. Assanioussi, A. Dapor, and J. Lewandowski, Phys. Lett. B 751, 302 (2015), 10.1016/j.physletb.2015.10.043], when some proper symmetry constraints are imposed, and we estimate the value of the deformation parameter for this case in loop quantum cosmology context.
On Cracking of Charged Anisotropic Polytropes
Azam, M
2016-01-01
Recently in \\cite{34}, the role of electromagnetic field on the cracking of spherical polytropes has been investigated without perturbing charge parameter explicitly. In this study, we have examined the occurrence of cracking of anisotropic spherical polytropes through perturbing parameters like anisotropic pressure, energy density and charge. We consider two different types of polytropes in this study. We discuss the occurrence of cracking in two different ways $(i)$ by perturbing polytropic constant, anisotropy and charge parameter $(ii)$ by perturbing polytropic index, anisotropy and charge parameter for each case. We conclude that cracking appears for a wide range of parameters in both cases. Also, our results are reduced to \\cite{33} in the absence of charge.
Anisotropic permeability in deterministic lateral displacement arrays
Vernekar, Rohan; Loutherback, Kevin; Morton, Keith; Inglis, David
2016-01-01
We investigate anisotropic permeability of microfluidic deterministic lateral displacement (DLD) arrays. A DLD array can achieve high-resolution bimodal size-based separation of micro-particles, including bioparticles such as cells. Correct operation requires that the fluid flow remains at a fixed angle with respect to the periodic obstacle array. We show via experiments and lattice-Boltzmann simulations that subtle array design features cause anisotropic permeability. The anisotropy, which indicates the array's intrinsic tendency to induce an undesired lateral pressure gradient, can lead to off-axis flows and therefore local changes in the critical separation size. Thus, particle trajectories can become unpredictable and the device useless for the desired separation duty. We show that for circular posts the rotated-square layout, unlike the parallelogram layout, does not suffer from anisotropy and is the preferred geometry. Furthermore, anisotropy becomes severe for arrays with unequal axial and lateral gaps...
Comparing anisotropic displacement parameters in protein structures.
Merritt, E A
1999-12-01
The increasingly widespread use of synchrotron-radiation sources and cryo-preparation of samples in macromolecular crystallography has led to a dramatic increase in the number of macromolecular structures determined at atomic or near-atomic resolution. This permits expansion of the structural model to include anisotropic displacement parameters U(ij) for individual atoms. In order to explore the physical significance of these parameters in protein structures, it is useful to be able to compare quantitatively the electron-density distribution described by the refined U(ij) values associated with corresponding crystallographically independent atoms. This paper presents the derivation of an easily calculated correlation coefficient in real space between two atoms modeled with anisotropic displacement parameters. This measure is used to investigate the degree of similarity between chemically equivalent but crystallographically independent atoms in the set of protein structural models currently available from the Protein Data Bank.
Anisotropic silica mesostructures for DNA encapsulation
Indian Academy of Sciences (India)
Aparna Ganguly; Ashok K Ganguli
2013-04-01
The encapsulation of biomolecules in inert meso or nanostructures is an important step towards controlling drug delivery agents. Mesoporous silica nanoparticles (MSN) are of immense importance owing to their high surface area, large pore size, uniform particle size and chemical inertness. Reverse micellar method with CTAB as the surfactant has been used to synthesize anisotropic mesoporous silica materials. We have used the anisotropic silica nanostructures for DNA encapsulation studies and observed a loading capacity of ∼8 g mg-1 of the sample. On functionalizing the pores of silica with amine group, the amount of DNA loaded on the rods decreases which is due to a reduction in the pore size upon grafting of amine groups.
Anomalous anisotropic magnetoresistance effects in graphene
Directory of Open Access Journals (Sweden)
Yiwei Liu
2014-09-01
Full Text Available We investigate the effect of external stimulus (temperature, magnetic field, and gases adsorptions on anisotropic magnetoresistance (AMR in multilayer graphene. The graphene sample shows superlinear magnetoresistance when magnetic field is perpendicular to the plane of graphene. A non-saturated AMR with a value of −33% is found at 10 K under a magnetic field of 7 T. It is surprisingly to observe that a two-fold symmetric AMR at high temperature is changed into a one-fold one at low temperature for a sample with an irregular shape. The anomalous AMR behaviors may be understood by considering the anisotropic scattering of carriers from two asymmetric edges and the boundaries of V+(V- electrodes which serve as active adsorption sites for gas molecules at low temperature. Our results indicate that AMR in graphene can be optimized by tuning the adsorptions, sample shape and electrode distribution in the future application.
Electromagnetic effects on cracking of anisotropic polytropes
Energy Technology Data Exchange (ETDEWEB)
Sharif, Muhammad; Sadiq, Sobia [University of the Punjab, Department of Mathematics, Lahore (Pakistan)
2016-10-15
In this paper, we study the electromagnetic effects on the stability of a spherically symmetric anisotropic fluid distribution satisfying two polytropic equations of state and construct the corresponding generalized Tolman-Oppenheimer-Volkoff equations. We apply perturbations on matter variables via the polytropic constant as well as the polytropic index and formulate the force distribution function. It is found that the compact object is stable for a feasible choice of perturbed polytropic index in the presence of charge. (orig.)
Crossing Statistics of Anisotropic Stochastic Surface
Nezhadhaghighi, M Ghasemi; Yasseri, T; Allaei, S M Vaez
2015-01-01
We use crossing statistics and its generalization to determine the anisotropic direction imposed on a stochastic fields in $(2+1)$Dimension. This approach enables us to examine not only the rotational invariance of morphology but also we can determine the Gaussianity of underlying stochastic field in various dimensions. Theoretical prediction of up-crossing statistics (crossing with positive slope at a given threshold $\\alpha$ of height fluctuation), $\
Symmetry analysis for anisotropic field theories
Energy Technology Data Exchange (ETDEWEB)
Parra, Lorena; Vergara, J. David [Instituto de Ciencias Nucleares, UNAM, Circuito Exterior s/n, Ciudad Universitaria. Delg. Coyoacan. C.P. 04510 Mexico DF (Mexico)
2012-08-24
The purpose of this paper is to study with the help of Noether's theorem the symmetries of anisotropic actions for arbitrary fields which generally depend on higher order spatial derivatives, and to find the corresponding current densities and the Noether charges. We study in particular scale invariance and consider the cases of higher derivative extensions of the scalar field, electrodynamics and Chern-Simons theory.
Electromagnetic field representation in inhomogeneous anisotropic media
Mohsen, A.
1973-01-01
Some of the basic developments in the theory of electromagnetic field representation in terms of Hertz vectors are reviewed. A solution for the field in an inhomogeneous anisotropic medium is given in terms of the two Hertz vectors. Conditions for presentation of the field in terms of uncoupled transverse electric and transverse magnetic modes, in a general orthogonal coordinate system, are derived when the permeability and permittivity tensors have only diagonal components. These conditions are compared with some known special cases.
Electromagnetic Effects on Cracking of Anisotropic Polytropes
Sharif, M
2016-01-01
In this paper, we study the electromagnetic effects on stability of spherically symmetric anisotropic fluid distribution satisfying two polytropic equations of state and construct the corresponding generalized Tolman Oppenheimer Volkoff equations. We apply perturbations on matter variables via polytropic constant as well as polytropic index and formulate the force distribution function. It is found that the compact object is stable for feasible choice of perturbed polytropic index in the presence of charge.
On anisotropic black branes with Lifshitz scaling
Directory of Open Access Journals (Sweden)
Dibakar Roychowdhury
2016-08-01
Full Text Available In this paper, based on the method of scalar perturbations, we construct the anisotropic charged Lifshitz background perturbatively up to leading order in the anisotropy. We perform our analysis both in the extremal as well as in the non-extremal limit. Finally, we probe the so called superfluid phase of the boundary theory and explore the effects of anisotropy on the superconducting condensate.
Anisotropic magnetocapacitance in ferromagnetic-plate capacitors
Haigh, J. A.; Ciccarelli, C.; Betz, A. C.; Irvine, A.; Novák, V.; Jungwirth, T.; Wunderlich, J.
2015-04-01
The capacitance of a parallel-plate capacitor can depend on the applied magnetic field. Previous studies have identified capacitance changes induced via classical Lorentz force or spin-dependent Zeeman effects. Here we measure a magnetization direction-dependent capacitance in parallel-plate capacitors where one plate is a ferromagnetic semiconductor, gallium manganese arsenide. This anisotropic magnetocapacitance is due to the anisotropy in the density of states dependent on the magnetization through the strong spin-orbit interaction.
Anisotropic Thermal Conductivity of Exfoliated Black Phosphorus.
Jang, Hyejin; Wood, Joshua D; Ryder, Christopher R; Hersam, Mark C; Cahill, David G
2015-12-22
The anisotropic thermal conductivity of passivated black phosphorus (BP), a reactive two-dimensional material with strong in-plane anisotropy, is ascertained. The room-temperature thermal conductivity for three crystalline axes of exfoliated BP is measured by time-domain thermo-reflectance. The thermal conductivity along the zigzag direction is ≈2.5 times higher than that of the armchair direction.
Acoustic anisotropic wavefields through perturbation theory
Alkhalifah, Tariq Ali
2013-09-01
Solving the anisotropic acoustic wave equation numerically using finite-difference methods introduces many problems and media restriction requirements, and it rarely contributes to the ability to resolve the anisotropy parameters. Among these restrictions are the inability to handle media with η<0 and the presence of shear-wave artifacts in the solution. Both limitations do not exist in the solution of the elliptical anisotropic acoustic wave equation. Using perturbation theory in developing the solution of the anisotropic acoustic wave equation allows direct access to the desired limitation-free solutions, that is, solutions perturbed from the elliptical anisotropic background medium. It also provides a platform for parameter estimation because of the ability to isolate the wavefield dependency on the perturbed anisotropy parameters. As a result, I derive partial differential equations that relate changes in the wavefield to perturbations in the anisotropy parameters. The solutions of the perturbation equations represented the coefficients of a Taylor-series-type expansion of the wavefield as a function of the perturbed parameter, which is in this case η or the tilt of the symmetry axis. The expansion with respect to the symmetry axis allows use of an acoustic transversely isotropic media with a vertical symmetry axis (VTI) kernel to estimate the background wavefield and the corresponding perturbation coefficients. The VTI extrapolation kernel is about one-fourth the cost of the transversely isotropic model with a tilt in the symmetry axis kernel. Thus, for a small symmetry axis tilt, the cost of migration using a first-order expansion can be reduced. The effectiveness of the approach was demonstrated on the Marmousi model.
Anisotropic cosmological solutions in massive vector theories
Heisenberg, Lavinia; Kase, Ryotaro; Tsujikawa, Shinji
2016-11-01
In beyond-generalized Proca theories including the extension to theories higher than second order, we study the role of a spatial component v of a massive vector field on the anisotropic cosmological background. We show that, as in the case of the isotropic cosmological background, there is no additional ghostly degrees of freedom associated with the Ostrogradski instability. In second-order generalized Proca theories we find the existence of anisotropic solutions on which the ratio between the anisotropic expansion rate Σ and the isotropic expansion rate H remains nearly constant in the radiation-dominated epoch. In the regime where Σ/H is constant, the spatial vector component v works as a dark radiation with the equation of state close to 1/3. During the matter era, the ratio Σ/H decreases with the decrease of v. As long as the conditions |Σ| ll H and v2 ll phi2 are satisfied around the onset of late-time cosmic acceleration, where phi is the temporal vector component, we find that the solutions approach the isotropic de Sitter fixed point (Σ = 0 = v) in accordance with the cosmic no-hair conjecture. In the presence of v and Σ the early evolution of the dark energy equation of state wDE in the radiation era is different from that in the isotropic case, but the approach to the isotropic value wDE(iso) typically occurs at redshifts z much larger than 1. Thus, apart from the existence of dark radiation, the anisotropic cosmological dynamics at low redshifts is similar to that in isotropic generalized Proca theories. In beyond-generalized Proca theories the only consistent solution to avoid the divergence of a determinant of the dynamical system corresponds to v = 0, so Σ always decreases in time.
Anisotropic nanomaterials: structure, growth, assembly, and functions
Panikkanvalappil R. Sajanlal; Theruvakkattil S. Sreeprasad; Samal, Akshaya K.; Thalappil Pradeep
2011-01-01
Comprehensive knowledge over the shape of nanomaterials is a critical factor in designing devices with desired functions. Due to this reason, systematic efforts have been made to synthesize materials of diverse shape in the nanoscale regime. Anisotropic nanomaterials are a class of materials in which their properties are direction-dependent and more than one structural parameter is needed to describe them. Their unique and fine-tuned physical and chemical properties make them ideal candidates...
Glucocorticoid-induced apoptosis and cellular mechanisms of myopathy.
Dirks-Naylor, Amie J; Griffiths, Carrie L
2009-10-01
Glucocorticoid-induced myopathy is a common side effect of chronic glucocorticoid therapy. Several mechanisms are currently being examined as ways in which glucocorticoid-induced myopathy occurs. These include apoptotic signaling through mitochondrial-mediated and Fas-mediated apoptosis, the role of the proteosome, the suppression of the IGF-1 signaling, and the role of ceramide in glucocorticoid-induced apoptosis and myopathy. It is difficult to differentiate which mechanism may be the initiating event responsible for the induction of apoptosis; however, all of the mechanisms play a vital role in glucocorticoid-induced myopathy.
Anisotropicity of Low Energy Direct Photons in Relativistic Heavy Ion Collisions
Koide, T
2016-01-01
We investigate the behavior of low energy photons radiated by deceleration processes of two colliding nuclei in relativistic heavy ion collisions, where their angular distribution reveals information of the initial geometric configurations. Such a property is reflected in the anisotropic parameter v_{2}, showing an increasing v_{2} as energy decreases, which is qualitatively different behavior from v_{2} from hadrons produced in the collisions.
On the existence of anisotropic cosmological models in higher order theories of gravity
Middleton, Jonathan
2010-01-01
Abstract We investigate the behaviour on approach to the initial singularity in higher-order extensions of general relativity by finding exact cosmological solutions for a wide class of models in which the Lagrangian is allowed to depend nonlinearly upon the three possible linear and quadratic scalars built from the Riemann tensor ; R, R ab R ab and R abcd R abcd. We present new anisotropic vacuum solutions analagous to the Kasner solutions of general relativity and extend previous results...
Anisotropic cosmological solutions in massive vector theories
Heisenberg, Lavinia; Tsujikawa, Shinji
2016-01-01
In beyond-generalized Proca theories including the extension to theories higher than second order, we study the role of a spatial component $v$ of a massive vector field on the anisotropic cosmological background. We show that, as in the case of the isotropic cosmological background, there is no additional ghostly degrees of freedom associated with the Ostrogradski instability. In second-order generalized Proca theories we find the existence of anisotropic solutions on which the ratio between the anisotropic expansion rate $\\Sigma$ and the isotropic expansion rate $H$ remains nearly constant in the radiation-dominated epoch. In the regime where $\\Sigma/H$ is constant, the spatial vector component $v$ works as a dark radiation with the equation of state close to $1/3$. During the matter era, the ratio $\\Sigma/H$ decreases with the decrease of $v$. As long as the conditions $|\\Sigma| \\ll H$ and $v^2 \\ll \\phi^2$ are satisfied around the onset of late-time cosmic acceleration, where $\\phi$ is the temporal vector ...
Anisotropic properties of TaS2
Institute of Scientific and Technical Information of China (English)
Qiao Yan-Bin; Li Yan-Ling; Zhong Guo-Hua; Zeng Zhi; Qin Xiao-Ying
2007-01-01
The anisotropic properties of 1T- and 2H-TaS2 are investigated by the density functional theory within the framework of full-potential linearized augmented plane wave method. The band structures of 1T- and 2H-TaS2 exhibit anisotropic properties and the calculated electronic specific-heat coefficient γ of 2H-TaS2 accords well with the existing experimental value. The anisotropic frequency-dependent dielectric functions including the effect of the Drude term are analysed, where the εxx(ω) spectra corresponding to the electric field E perpendicular to the z axis show excellent agreement with the measured results except for the ε1xx(ω) of 1T-TaS2 below the energy level of 2.6 eV which is due to the lack of the enough CDW information for reference in our calculation. Furthermore, based on the values of optical effective mass ratio P of 1T and 2H phases it is found that the anisotropy in 2H-TaS2 is stronger than that in 1T-TaS2.
Anisotropic Optical Properties of Layered Germanium Sulfide
Tan, Dezhi; Wang, Feijiu; Mohamed, Nur Baizura; Mouri, Shinichiro; Sandhaya, Koirala; Zhang, Wenjing; Miyauchi, Yuhei; Ohfuchi, Mari; Matsuda, Kazunari
2016-01-01
Two-dimensional (2D) layered materials, transition metal dichalcogenides and black phosphorus, have attracted much interest from the viewpoints of fundamental physics and device applications. The establishment of new functionalities in anisotropic layered 2D materials is a challenging but rewarding frontier, owing to their remarkable optical properties and prospects for new devices. Here, we report the anisotropic optical properties of layered 2D monochalcogenide of germanium sulfide (GeS). Three Raman scattering peaks corresponding to the B3g, A1g, and A2g modes with strong polarization dependence are demonstrated in the GeS flakes, which validates polarized Raman spectroscopy as an effective method for identifying the crystal orientation of anisotropic layered GeS. Photoluminescence (PL) is observed with a peak at around 1.66 eV that originates from the direct optical transition in GeS at room temperature. Moreover, determination of the polarization dependent characteristics of the PL and absorption reveals...
ARTc: Anisotropic reflectivity and transmissivity calculator
Malehmir, Reza; Schmitt, Douglas R.
2016-08-01
While seismic anisotropy is known to exist within the Earth's crust and even deeper, isotropic or even highly symmetric elastic anisotropic assumptions for seismic imaging is an over-simplification which may create artifacts in the image, target mis-positioning and hence flawed interpretation. In this paper, we have developed the ARTc algorithm to solve reflectivity, transmissivity as well as velocity and particle polarization in the most general case of elastic anisotropy. This algorithm is able to provide reflectivity solution from the boundary between two anisotropic slabs with arbitrary symmetry and orientation up to triclinic. To achieve this, the algorithm solves full elastic wave equation to find polarization, slowness and amplitude of all six wave-modes generated from the incident plane-wave and welded interface. In the first step to calculate the reflectivity, the algorithm solves properties of the incident wave such as particle polarization and slowness. After calculation of the direction of generated waves, the algorithm solves their respective slowness and particle polarization. With this information, the algorithm then solves a system of equations incorporating the imposed boundary conditions to arrive at the scattered wave amplitudes, and thus reflectivity and transmissivity. Reflectivity results as well as slowness and polarization are then tested in complex computational anisotropic models to ensure their accuracy and reliability. ARTc is coded in MATLAB ® and bundled with an interactive GUI and bash script to run on single or multi-processor computers.
Anisotropic and Hierarchical Porosity in Multifunctional Ceramics
Lichtner, Aaron Zev
The performance of multifunctional porous ceramics is often hindered by the seemingly contradictory effects of porosity on both mechanical and non-structural properties and yet a sufficient body of knowledge linking microstructure to these properties does not exist. Using a combination of tailored anisotropic and hierarchical materials, these disparate effects may be reconciled. In this project, a systematic investigation of the processing, characterization and properties of anisotropic and isotropic hierarchically porous ceramics was conducted. The system chosen was a composite ceramic intended as the cathode for a solid oxide fuel cell (SOFC). Comprehensive processing investigations led to the development of approaches to make hierarchical, anisotropic porous microstructures using directional freeze-casting of well dispersed slurries. The effect of all the important processing parameters was investigated. This resulted in an ability to tailor and control the important microstructural features including the scale of the microstructure, the macropore size and total porosity. Comparable isotropic porous ceramics were also processed using fugitive pore formers. A suite of characterization techniques including x-ray tomography and 3-D sectional scanning electron micrographs (FIB-SEM) was used to characterize and quantify the green and partially sintered microstructures. The effect of sintering temperature on the microstructure was quantified and discrete element simulations (DEM) were used to explain the experimental observations. Finally, the comprehensive mechanical properties, at room temperature, were investigated, experimentally and using DEM, for the different microstructures.
Directory of Open Access Journals (Sweden)
C. Haanen
1995-01-01
Full Text Available During the last few decades it has been recognized that cell death is not the consequence of accidental injury, but is the expression of a cell suicide programme. Kerr et al. (1972 introduced the term apoptosis. This form of cell death is under the influence of hormones, growth factors and cytokines, which depending upon the receptors present on the target cells, may activate a genetically controlled cell elimination process. During apoptosis the cell membrane remains intact and the cell breaks into apoptotic bodies, which are phagocytosed. Apoptosis, in contrast to necrosis, is not harmful to the host and does not induce any inflammatory reaction. The principal event that leads to inflammatory disease is cell damage, induced by chemical/physical injury, anoxia or starvation. Cell damage means leakage of cell contents into the adjacent tissues, resulting in the capillary transmigration of granulocytes to the injured tissue. The accumulation of neutrophils and release of enzymes and oxygen radicals enhances the inflammatory reaction. Until now there has been little research into the factors controlling the accumulation and the tissue load of granulocytes and their histotoxic products in inflammatory processes. Neutrophil apoptosis may represent an important event in the control of intlamtnation. It has been assumed that granulocytes disintegrate to apoptotic bodies before their fragments are removed by local macrophages. Removal of neutrophils from the inflammatory site without release of granule contents is of paramount importance for cessation of inflammation. In conclusion, apoptotic cell death plays an important role in inflammatory processes and in the resolution of inflammatory reactions. The facts known at present should stimulate further research into the role of neutrophil, eosinophil and macrophage apoptosis in inflammatory diseases.
van Dillen, T.; van der Giessen, E.; Onck, P. R.; Polman, A.
2006-01-01
We develop a phenomenological model for size-dependent anisotropic plastic deformation of colloidal nanoparticles under ion irradiation. We show that, at the nanoscale, nonhydrostatic capillary stresses drive radiation-induced Newtonian viscous flow, counteracting the stress state that initiates the
Li, Xianping
2010-01-01
Heterogeneous anisotropic diffusion problems arise in the various areas of science and engineering including plasma physics, petroleum engineering, and image processing. Standard numerical methods can produce spurious oscillations when they are used to solve those problems. A common approach to avoid this difficulty is to design a proper numerical scheme and/or a proper mesh so that the numerical solution validates the discrete counterpart (DMP) of the maximum principle satisfied by the continuous solution. A well known mesh condition for the DMP satisfaction by the linear finite element solution of isotropic diffusion problems is the non-obtuse angle condition that requires the dihedral angles of mesh elements to be non-obtuse. In this paper, a generalization of the condition, the so-called anisotropic non-obtuse angle condition, is developed for the finite element solution of heterogeneous anisotropic diffusion problems. The new condition is essentially the same as the existing one except that the dihedral ...
Chen, Wei-Hai; Luo, Guo-Feng; Xu, Xiao-Ding; Jia, Hui-Zhen; Lei, Qi; Han, Kai; Zhang, Xian-Zheng
2014-07-01
A versatile gold nanoparticle-based multifunctional RB-DEVD-AuNP-DTP has been developed to induce the targeted apoptosis of cancer cells and image in real time the progress of the apoptosis. The multifunctional nanoparticles were demonstrated to have the ability to initiate mitochondria-dependent apoptosis and activate caspase-3 for real-time imaging of the progression of apoptosis.A versatile gold nanoparticle-based multifunctional RB-DEVD-AuNP-DTP has been developed to induce the targeted apoptosis of cancer cells and image in real time the progress of the apoptosis. The multifunctional nanoparticles were demonstrated to have the ability to initiate mitochondria-dependent apoptosis and activate caspase-3 for real-time imaging of the progression of apoptosis. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr02516d
Modelling of a compact anisotropic star as an anisotropic fluid sphere in $f(T)$ gravity
Momeni, D; Qaisar, S; Zaz, Zaid; Myrzakulov, R
2016-01-01
In this paper, we have studied the new exact model of anisotropic star in $f(T)$ theory of gravity. The dynamical equations in $f(T)$ theory with the anisotropic fluid have been solved by using Krori-Barua solution. We have determined that all the obtained solutions are free from central singularity and potentially stable. The observed values of mass and radius of the different strange stars RX J 1856-37, Her X-1, and Vela X-12 have been used to calculate the values of unknown constants in Krori and Barua metric. The physical parameters like anisotropy, stability and redshift of the stars have been investigated in detail.
Enhancement of non-resonant dielectric cloaks using anisotropic composites
Takezawa, Akihiro
2014-01-01
The effectiveness of homogenized anisotropic materials in non-resonant dielectric multilayer cloaking is studied. Because existing multilayer cloaking by isotropic materials can be regarded as homogenous anisotropic cloaking from a macroscopic view, they can be efficiently designed by handling the physical properties of anisotropic materials directly. Anisotropic properties can be realized in two-phase composites if the physical properties of the material are within appropriate bounds. The optimized anisotropic physical properties are identified by a numerical optimization technique based on a full-wave simulation using the finite element method. The cloaking performance measured by the total scattering width is improved by about 10% compared with existing multilayer cloaking by isotropic materials in eight-layer cylindrical cloaking materials. The same performance with eight-layer cloaking by isotropic materials is achieved by three-layer cloaking using anisotropic materials. Cloaking with a about 50% reduct...
Grooved organogel surfaces towards anisotropic sliding of water droplets.
Zhang, Pengchao; Liu, Hongliang; Meng, Jingxin; Yang, Gao; Liu, Xueli; Wang, Shutao; Jiang, Lei
2014-05-21
Periodic micro-grooved organogel surfaces can easily realize the anisotropic sliding of water droplets attributing to the formed slippery water/oil/solid interface. Different from the existing anisotropic surfaces, this novel surface provides a versatile candidate for the anisotropic sliding of water droplets and might present a promising way for the easy manipulation of liquid droplets for water collection, liquid-directional transportation, and microfluidics.
Fronts of Stress Wave in Anisotropic Piezoelectric Media
Institute of Scientific and Technical Information of China (English)
刘颖; 刘凯欣; 高凌天
2004-01-01
The characteristic of wave fronts in anisotropic piezoelectric media is analysed by adopting the generalized characteristic theory. Analytical expressions for wave velocities and wave fronts are formulated. Apart from the ordinary characteristics, a new phenomenon, energy velocity funnel, is formed on the wave fronts of quasitransverse waves in anisotropic piezoelectric materials. A three-dimensional representation of wave fronts in anisotropic piezoelectric materials is given for a better understanding of the new phenomena.
Orthonormal bases for anisotropic α-modulation spaces
DEFF Research Database (Denmark)
Rasmussen, Kenneth Niemann
2012-01-01
In this article we construct orthonormal bases for bi-variate anisotropic α-modulation spaces. The construction is based on generating a nice anisotropic α-covering and using carefully selected tensor products of univariate brushlet functions with regards to this covering. As an application, we...... show that n-term nonlinear approximation with the orthonormal bases in certain anisotropic α-modulation spaces can be completely characterized....
Orthonormal bases for anisotropic α-modulation spaces
DEFF Research Database (Denmark)
Rasmussen, Kenneth Niemann
In this article we construct orthonormal bases for bi-variate anisotropic α-modulation spaces. The construction is based on generating a nice anisotropic α-covering and using carefully selected tensor products of univariate brushlet functions with regards to this covering. As an application, we...... show that n-term nonlinear approximation with the orthonormal bases in certain anisotropic α-modulation spaces can be completely characterized....
An eigen theory of static electromagnetic field for anisotropic media
Institute of Scientific and Technical Information of China (English)
Shao-hua GUO
2009-01-01
Static electromagnetic fields are studied based on standard spaces of the physical presentation,and the modal equations of static electromagnetic fields for anisotropic media are derived. By introducing a new set of first-order potential functions,several novel theoretical results are obtained. It is found that,for isotropic media,electric or magnetic potentials are scalar; while for anisotropic media,they are vectors. Magnitude and direction of the vector potentials are related to the anisotropic subspaces. Based on these results,we discuss the laws of static electromagnetic fields for anisotropic media.
Directory of Open Access Journals (Sweden)
M. A. Orlova
2014-07-01
Full Text Available Fullerene derivatives superfamily attracts a serious attention as antiviral and anticancer agents and drug delivery carriers as well. A large number of such fullerene С60 derivatives obtained to date. However, there is an obvious deficit of information about causes and mechanisms of immediately and long-term consequences of their effects in vivo which is a true obstacle on the way leading to practical medical use of them. First, this concerns their impact on the proliferation, apoptosis and necrosis regulation. Fullerene nanoparticle functionalization type, their sizes and surface nanopathology are of great importance to further promoting of either cytoprotective or cytotoxic effects. This lecture provides modern concept analysis regarding fullerenes effects on apoptosis pathway in normal and tumor cells.
Directory of Open Access Journals (Sweden)
M. A. Orlova
2013-01-01
Full Text Available Fullerene derivatives superfamily attracts a serious attention as antiviral and anticancer agents and drug delivery carriers as well. A large number of such fullerene С60 derivatives obtained to date. However, there is an obvious deficit of information about causes and mechanisms of immediately and long-term consequences of their effects in vivo which is a true obstacle on the way leading to practical medical use of them. First, this concerns their impact on the proliferation, apoptosis and necrosis regulation. Fullerene nanoparticle functionalization type, their sizes and surface nanopathology are of great importance to further promoting of either cytoprotective or cytotoxic effects. This lecture provides modern concept analysis regarding fullerenes effects on apoptosis pathway in normal and tumor cells.
Directory of Open Access Journals (Sweden)
Manjul Tiwari
2011-01-01
Full Text Available The term apoptosis first appeared in the biomedical literature in 1972, to delineate a structurally distinctive mode of cell death responsible for cell loss within living tissues. The cardinal morphological features are cell shrinkage, accompanied by transient but violent bubbling and blebbing from the surface, and culminating in separation of the cell into a cluster of membrane-bounded bodies. Changes in several cell surface molecules also ensure that, in tissues, apoptotic cells are immediately recognised and phagocytosed by their neighbours. However, it is important to note that apoptosis is only one form of cell death and the particular death pathway that is the most important determinant for cancer therapy is not necessarily that which has the fastest kinetics, as is the bias in many laboratories, but rather that which displays the most sensitive dose-response relationship.
Apoptosis: una muerte silenciosa
Directory of Open Access Journals (Sweden)
Isis Casadelvalle Pérez
2006-01-01
Full Text Available La apoptosis o muerte celular programada es un tipo de muerte presente en todas las células eucarióticas. Es un proceso ordenado y esencial del desarrollo normal y de mantenimiento de la homeostasis de un organismo. En el presente trabajo se resumen las principales características fisiológicas, bioquímicas y moleculares de la muerte por apoptosis, evento que ocurre de forma apagada o silenciosa, o sea, sin daño celular aparente diferenciándose claramente del proceso de necrosis celular. En ese proceso se destaca la mitocondria, como organelo celular donde mediado por la activación de las caspasas se inicia el paso hacia la muerte celular programada. En el momento actual, la apoptosis ha cobrado un verdadero valor para la mejor comprensión de los procesos biológicos normales en los que este evento está involucrado y que con anterioridad no era tomado en cuenta. En este sentido, se comentan las principales técnicas de detección de muerte celular programada y se aclara que la elección de algunas de ellas depende del modelo de estudio. Tambi én se dan a conocer algunas de las patologías generales en las que este proceso representa un papel determinante y se discute acerca de cómo algunas alteraciones en los mecanismos de regulación de la apoptosis inducen la aparici ón de varias enfermedades, incluyendo aquellos desórdenes en los que ocurre acumulación celular (cáncer, alteración cardiaca, neurodegeneración y SIDA. El estudio y caracterización de este complejo mecanismo ha cambiado profundamente la comprensión de numerosas patologías en los organismos eucariotas.
Anisotropic expansion and SNIa: An open issue
Directory of Open Access Journals (Sweden)
Jose Beltrán Jiménez
2015-02-01
Full Text Available We review the appropriateness of using SNIa observations to detect potential signatures of anisotropic expansion in the Universe. We focus on Union2 and SNLS3 SNIa datasets and use the hemispherical comparison method to detect possible anisotropic features. Unlike some previous works where non-diagonal elements of the covariance matrix were neglected, we use the full covariance matrix of the SNIa data, thus obtaining more realistic and not underestimated errors. As a matter of fact, the significance of previously claimed detections of a preferred direction in the Union2 dataset completely disappears once we include the effects of using the full covariance matrix. Moreover, we also find that such a preferred direction is aligned with the orthogonal direction of the SDSS observational plane and this suggests a clear indication that the SDSS subsample of the Union2 dataset introduces a significant bias, making the detected preferred direction unphysical. We thus find that current SNIa surveys are inappropriate to test anisotropic features due to their highly non-homogeneous angular distribution in the sky. In addition, after removal of the highest inhomogeneous sub-samples, the number of SNIa is too low. Finally, we take advantage of the particular distribution of SNLS SNIa sub-sample in the SNLS3 data set, in which the observations were taken along four different directions. We fit each direction independently and find consistent results at the 1σ level. Although the likelihoods peak at relatively different values of Ωm, the low number of data along each direction gives rise to large errors so that the likelihoods are sufficiently broad as to overlap within 1σ.
Computation of Large Anisotropic Seismic Heterogeneities (CLASH)
Beucler, Éric; Montagner, Jean-Paul
2006-05-01
A general tomographic technique is designed in order (i) to operate in anisotropic media; (ii) to account for the uneven seismic sampling and (iii) to handle massive data sets in a reasonable computing time. One modus operandi to compute a 3-D body wave velocity model relies on surface wave phase velocity measurements. An intermediate step, shared by other approaches, consists in translating, for each period of a given mode branch, the phase velocities integrated along ray paths into local velocity perturbations. To this end, we develop a method, which accounts for the azimuthal anisotropy in its comprehensive form. The weakly non-linear forward problem allows to use a conjugate gradient optimization. The Earth's surface is regularly discretized and the partial derivatives are assigned to the individual grid points. Possible lack of lateral resolution, due to the inescapable uneven ray path coverage, is taken into account through the a priori covariances on parameters with laterally variable correlation lengths. This method allows to efficiently separate the 2ψ and the 4ψ anisotropic effects from the isotropic perturbations. Fundamental mode and overtone phase velocity maps, derived with real Rayleigh wave data sets, are presented and compared with previous maps. The isotropic models concur well with the results of Trampert & Woodhouse. Large 4ψ heterogeneities are located in the tectonically active regions and over the continental lithospheres such as North America, Antarctica or Australia. At various periods, a significant 4ψ signature is correlated with the Hawaii hotspot track. Finally, concurring with the conclusions of Trampert & Woodhouse, our phase velocity maps show that Rayleigh wave data sets do need both 2ψ and 4ψ anisotropic terms.
Sphingolipids and mitochondrial apoptosis.
Patwardhan, Gauri A; Beverly, Levi J; Siskind, Leah J
2016-04-01
The sphingolipid family of lipids modulate several cellular processes, including proliferation, cell cycle regulation, inflammatory signaling pathways, and cell death. Several members of the sphingolipid pathway have opposing functions and thus imbalances in sphingolipid metabolism result in deregulated cellular processes, which cause or contribute to diseases and disorders in humans. A key cellular process regulated by sphingolipids is apoptosis, or programmed cell death. Sphingolipids play an important role in both extrinsic and intrinsic apoptotic pathways depending on the stimuli, cell type and cellular response to the stress. During mitochondrial-mediated apoptosis, multiple pathways converge on mitochondria and induce mitochondrial outer membrane permeabilization (MOMP). MOMP results in the release of intermembrane space proteins such as cytochrome c and Apaf1 into the cytosol where they activate the caspases and DNases that execute cell death. The precise molecular components of the pore(s) responsible for MOMP are unknown, but sphingolipids are thought to play a role. Here, we review evidence for a role of sphingolipids in the induction of mitochondrial-mediated apoptosis with a focus on potential underlying molecular mechanisms by which altered sphingolipid metabolism indirectly or directly induce MOMP. Data available on these mechanisms is reviewed, and the focus and limitations of previous and current studies are discussed to present important unanswered questions and potential future directions.
Directory of Open Access Journals (Sweden)
Arpan Laskar
2017-01-01
Full Text Available Many practical engineering problems are seriously different from the assumptions which are considered for one-dimensional consolidation test and need to concentrate on three-dimensional consolidation of soil under different boundary conditions. In this study three-dimensional consolidation tests are performed with four different anisotropic flow conditions of pore water and fifteen different combinations of horizontal layered soils. Twelve different three-dimensional consolidation tests are also performed with different soils, surrounded by anisotropic vertical soil layers on two opposite sides. From these studies, it is observed that the anisotropic flow of pore water does not have any effect on initial and final surface settlement of soil but has a significant effect during the consolidation process. The anisotropic flow of pore water during the consolidation process has an immense effect on the coefficient of consolidation. Horizontal layered soil has a great effect on both surface settlement and the rate of settlement. Vertical soil layers on two opposite sides of consolidative soil have an immense effect on the horizontal movements of consolidating soil, finally affecting the resultant vertical settlement of soil. Vertical anisotropic surrounding soil layers also have an effect on the rate of consolidation settlement.
Ultrasonic Linear Motor with Anisotropic Composite
Institute of Scientific and Technical Information of China (English)
曾周末; 王新辉; 赵伯雷
2004-01-01
An idea to make up the vibrating body of ultrasonic motor with anisotropic composite is proposed and a linear piezoelectric motor is developed in this paper. Relative problems such as actuating mechanism, resonant frequency are discussed theoretically. According to the feature that impulse exists between the elastic body of composite ultrasonic linear motor and the base, an impulse analysis is presented to calculate the motor′s friction driving force and frictional conversion efficiency. The impulse analysis essentially explains the reason why the ultrasonic motor has great driving force, and can be applied to analyze the non-linear ultrasonic motor.
Wireless energy transfer between anisotropic metamaterials shells
Diaz-Rubio, Ana; Sanchez-Dehesa, Jose
2013-01-01
The behavior of strongly coupled Radial Photonic Crystals shells is investigated as a potential alternative to transfer electromagnetic energy wirelessly. These sub-wavelength resonant microstructures, which are based on anisotropic metamaterials, can produce efficient coupling phenomena due to their high quality factor. A configuration of selected constitutive parameters (permittivity and permeability) is analyzed in terms of its resonant characteristics. The coupling to loss ratio between two coupled resonators is calculated as a function of distance, the maximum (in excess of 300) is obtained when the shells are separated by three times their radius. Under practical conditions an 83% of maximum power transfer has been also estimated.
Anisotropic Density Estimation in Global Illumination
DEFF Research Database (Denmark)
Schjøth, Lars
2009-01-01
Density estimation employed in multi-pass global illumination algorithms gives cause to a trade-off problem between bias and noise. The problem is seen most evident as blurring of strong illumination features. This thesis addresses the problem, presenting four methods that reduce both noise...... and bias in estimates. Good results are obtained by the use of anisotropic filtering. Two methods handles the most common cases; filtering illumination reflected from object surfaces. One methods extends filtering to the temporal domain and one performs filtering on illumination from participating media...
On Radiative Fluids in Anisotropic Spacetimes
Shogin, Dmitry
2016-01-01
We apply the second-order Israel-Stewart theory of relativistic fluid- and thermodynamics to a physically realistic model of a radiative fluid in a simple anisotropic cosmological background. We investigate the asymptotic future of the resulting cosmological model and review the role of the dissipative phenomena in the early Universe. We demonstrate that the transport properties of the fluid alone, if described appropriately, do not explain the presently observed accelerated expansion of the Universe. Also, we show that, in constrast to the mathematical fluid models widely used before, the radiative fluid does approach local thermal equilibrium at late times, although very slowly, due to the cosmological expansion.
Multichannel image regularization using anisotropic geodesic filtering
Energy Technology Data Exchange (ETDEWEB)
Grazzini, Jacopo A [Los Alamos National Laboratory
2010-01-01
This paper extends a recent image-dependent regularization approach introduced in aiming at edge-preserving smoothing. For that purpose, geodesic distances equipped with a Riemannian metric need to be estimated in local neighbourhoods. By deriving an appropriate metric from the gradient structure tensor, the associated geodesic paths are constrained to follow salient features in images. Following, we design a generalized anisotropic geodesic filter; incorporating not only a measure of the edge strength, like in the original method, but also further directional information about the image structures. The proposed filter is particularly efficient at smoothing heterogeneous areas while preserving relevant structures in multichannel images.
Temperature and Polarization Patterns in Anisotropic Cosmologies
Sung, Rockhee
2010-01-01
We study the coherent temperature and polarization patterns produced in homogeneous but anisotropic cosmological models. We show results for all Bianchi types with a Friedman-Robertson-Walker limit (i.e. Types I, V, VII$_{0}$, VII$_{h}$ and IX) to illustrate the range of possible behaviour. We discuss the role of spatial curvature, shear and rotation in the geodesic equations for each model and establish some basic results concerning the symmetries of the patterns produced. We also give examples of the time-evolution of these patterns in terms of the Stokes parameters $I$, $Q$ and $U$.
Relativistic Cyclotron Instability in Anisotropic Plasmas
López, Rodrigo A.; Moya, Pablo S.; Navarro, Roberto E.; Araneda, Jaime A.; Muñoz, Víctor; Viñas, Adolfo F.; Alejandro Valdivia, J.
2016-11-01
A sufficiently large temperature anisotropy can sometimes drive various types of electromagnetic plasma micro-instabilities, which can play an important role in the dynamics of relativistic pair plasmas in space, astrophysics, and laboratory environments. Here, we provide a detailed description of the cyclotron instability of parallel propagating electromagnetic waves in relativistic pair plasmas on the basis of a relativistic anisotropic distribution function. Using plasma kinetic theory and particle-in-cell simulations, we study the influence of the relativistic temperature and the temperature anisotropy on the collective and noncollective modes of these plasmas. Growth rates and dispersion curves from the linear theory show a good agreement with simulations results.
Hydrodynamics of anisotropic quark and gluon fluids
Florkowski, Wojciech; Maj, Radoslaw; Ryblewski, Radoslaw; Strickland, Michael
2013-03-01
The recently developed framework of anisotropic hydrodynamics is generalized to describe the dynamics of coupled quark and gluon fluids. The quark and gluon components of the fluids are characterized by different dynamical anisotropy parameters. The dynamical equations describing such mixtures are derived from kinetic theory, with the collisional kernel treated in the relaxation-time approximation, allowing for different relaxation times for quarks and gluons. Baryon number conservation is enforced in the quark and antiquark components of the fluid, but overall parton number nonconservation is allowed in the system. The resulting equations are solved numerically in the (0+1)-dimensional boost-invariant case at zero and finite baryon density.
Hydrodynamics of anisotropic quark and gluon fluids
Florkowski, Wojciech; Ryblewski, Radoslaw; Strickland, Michael
2012-01-01
The recently developed framework of anisotropic hydrodynamics is generalized to describe the dynamics of coupled quark and gluon fluids. The quark and gluon components of the fluids are characterized by different dynamical anisotropy parameters. The dynamical equations describing such mixtures are derived from kinetic theory with the collisional kernel treated in the relaxation-time approximation. Baryon number conservation is enforced in the quark and anti-quark components of the fluid, but overall parton number non-conservation is allowed in the system. The resulting equations are solved numerically in the (0+1)-dimensional boost-invariant case at zero and finite baryon density.
Anisotropic Spin Cluster as a Qubit
Institute of Scientific and Technical Information of China (English)
YAN Xiao-Bo; WANG Ming-Ji
2007-01-01
We study an anisotropic spin cluster of 3 spin S=1/2 particles with antiferromagnetic exchange interaction with non-uniform coupling constants. A time-dependent magnetic field is applied to control the time evolution of the cluster. It is well known that for an odd number og sites a spin cluster qubit can be defined in terms of the ground state doublet. The universal one-qubit logic gate can be constructed from the time evolution operator of the non-autonomous many-body system, and the six basic one-qubit gates can be realized by adjusting the applied time-dependent magnetic field.
Silicon as an anisotropic mechanical material
DEFF Research Database (Denmark)
Thomsen, Erik Vilain; Reck, Kasper; Skands, Gustav Erik
2014-01-01
While silicon is an anisotropic material it is often in literature treated as an isotropic material when it comes to plate calculations. This leads to considerable errors in the calculated deflection. To overcome this problem, we present an in-depth analysis of the bending behavior of thin...... analytical models involving crystalline plates, such as those often found in the field of micro electro mechanical systems. The effect of elastic boundary conditions is taken into account by using an effective radius of the plate....
Generalized Jones matrices for anisotropic media.
Ortega-Quijano, Noé; Arce-Diego, José Luis
2013-03-25
The interaction of arbitrary three-dimensional light beams with optical elements is described by the generalized Jones calculus, which has been formally proposed recently [Azzam, J. Opt. Soc. Am. A 28, 2279 (2011)]. In this work we obtain the parametric expression of the 3×3 differential generalized Jones matrix (dGJM) for arbitrary optical media assuming transverse light waves. The dGJM is intimately connected to the Gell-Mann matrices, and we show that it provides a versatile method for obtaining the macroscopic GJM of media with either sequential or simultaneous anisotropic effects. Explicit parametric expressions of the GJM for some relevant optical elements are provided.
Charged Anisotropic Star on Paraboloidal Spacetime
Ratanpal, B S
2015-01-01
The charged anisotropic star on paraboloidal spacetime is reported by choosing particular form of radial pressure and electric field intensity. The non-singular solution of Einstein-Maxwell system of equation have been derived and it is shown that model satisfy all the physical plausibility conditions. It is observed that in the absence of electric field intensity, model reduces to particular case of uncharged Sharma \\& Ratanpal model. It is also observed that the parameter used in electric field intensity directly effects the mass of the star.
Self-organized motion in anisotropic swarms
Institute of Scientific and Technical Information of China (English)
Tianguang CHU; Long WANG; Tongwen CHEN
2003-01-01
This paper considers an anisotropic swarm model with a class of attraction and repulsion functions. It is shown that the members of the swarm will aggregate and eventually form a cohesive cluster of finite size around the swarm center. Moreover,It is also proved that under certain conditions, the swarm system can be completely stable, i. e., every solution converges to the equilibrium points of the system. The model and results of this paper extend a recent work on isotropic swarms to more general cases and provide further insight into the effect of the interaction pattern on self-organized motion in a swarm system.
Phenomenological aspects of an anisotropic quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Martinez Guerrero, Mauricio
2010-04-30
In this work we investigate phenomenological aspects of an anisotropic quark-gluon plasma. In the first part of this thesis, we formulate phenomenologicalmodels that take into account the momentumspace anisotropy of the system developed during the expansion of the fireball at early-times. By including the proper-time dependence of the parton hard momentum scale, p{sub hard}({tau}), and the plasma anisotropy parameter, {xi}({tau}), the proposed models allow us to interpolate from 0+1 pre-equilibrated expansion at early-times to 0+1 ideal hydrodynamics at late times. We study dilepton production as a valuable observable to experimentally determine the isotropization time of the system as well as the degree of anisotropy developed at early-times. We generalize our interpolating models to include the rapidity dependence of p{sub hard} and consider its impact on forward dileptons. Next, we discuss how to constrain the onset of hydrodynamics by demanding two requirements of the solutions to the equations of motion of viscous hydrodynamics. We show this explicitly for 0+1 dimensional 2nd-order conformal viscous hydrodynamics and find that the initial conditions are non-trivially constrained. Finally, we demonstrate how to match the initial conditions for 0+1 dimensional viscous hydrodynamics from pre-equilibrated expansion. We analyze the dependence of the entropy production on the pre-equilibrium phase and discuss limitations of the standard definitions of the non-equilibrium entropy in kinetic theory. (orig.)
Anisotropic distributions in a multi-phase transport model
Zhou, You; Feng, Zhao; Liu, Feng; Snellings, Raimond
2015-01-01
With A Multi-Phase Transport (AMPT) model we investigate the relation between the magnitude, fluctuations and correlations of the initial state spatial anisotropy $\\varepsilon_{n}$ and the final state anisotropic flow coefficients $v_{n}$ in Au+Au collisions at $\\sqrt{s_{_{\\rm NN}}}=$ 200 GeV. It is found that the relative eccentricity fluctuations in AMPT account for the observed elliptic flow fluctuations, in agreement with measurements of the STAR collaboration. In addition, the studies based on 2- and multi-particle correlations and event-by-event distributions of the anisotropies suggest that the Elliptic-Power function is a promising candidate of the underlying probability density function of the event-by-event distributions of $\\varepsilon_{n}$ as well as $v_{n}$. Furthermore, the correlations between different order symmetry planes and harmonics in the initial coordinate space and final state momentum space are presented. Non-zero values of these correlations have been observed. The comparison between...
Ordering the multiple pathways of apoptosis.
Park, D S; Stefanis, L; Greene, L A
1997-11-01
Apoptosis plays an important role in development, homeostasis, and disease. Current work has suggested that apoptosis can be evoked by multiple stimuli that, in turn, initiate distinct death pathways. Recently, exciting advances have been made in the understanding of biochemical pathways that regulate apoptotic processes. These pathways contain both evolutionarily conserved elements and components that are dependent on the death stimulus and cell context. Accordingly, this review focuses on the compositions and relative ordering of the apoptotic pathways in four different death paradigms: activation of receptors of the Fas ligand, destruction by cytotoxic T lymphocytes, exposure to DNA damaging agents, and loss of support by neurotrophic factors. These examples illustrate the conservation and divergence in the ways that death pathways are composed and ordered. (Trends Cardiovasc Med 1997;7:294-301). © 1997, Elsevier Science Inc.
Necking of anisotropic micro-films with strain-gradient effects
Institute of Scientific and Technical Information of China (English)
Brian Nyvang Legarth
2008-01-01
Necking of stubby micro-films of aluminum is investigated numerically by considering tension of a speci-men with an initial imperfection used to onset localisation. Plastic anisotropy is represented by two different yield cri-teria and strain-gradient effects are accounted for using the visco-plastic finite strain model. Furthermore, the model is extended to isotropic anisotropic hardening (evolving aniso-tropy). For isotropic hardening plastic anisotropy affects the predicted overall nominal stress level, while the peak stress remains at an overall logarithmic strain corresponding to the hardening exponent. This holds true for both local and non-local materials. Anisotropic hardening delays the point of maximum overall nominal stress.
BEM Analysis of Wave Propagation in a Water-Filled Borehole in an Anisotropic Solid
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
This paper describes a time-domain boundary element method developed to analyze the interactions of acoustic and elastic waves near the interfaces between water and an anisotropic elastic solid. Two models are analyzed with one being the interface between two half spaces of fluid and solid and the other being a fluid region sandwiched by half space domains of anisotropic elastic solids. Both monopole and dipole point sources are used to generate an initial pressure wave in the fluid. Some snapshots of the transient wave behavior near the fluid-solid interfaces are given. The effect of the anisotropy in the solid on the pressure waveforms in the fluid is discussed. The numerical results allow detailed arrival identification and interpretation of acoustic and elastic waves propagating along the fluid-solid interfaces.
Quantitative analysis of deformation in hollow cylinder tests on anisotropic clay formations
Institute of Scientific and Technical Information of China (English)
You Shuang; Ji Hongguang; Labiouse Vincent; Hall Stephen A.; Viggiani Gioacchino
2015-01-01
A series of triaxial laboratory experiments are performed on thick-walled hollow cylindrical samples of boom clay. The aim of this testing program is to better understand the anisotropic deformation during the excavation. The testing conditions are similar to those to be experienced by host rocks around disposal galleries for radioactive waste. X-ray computed tomography is performed at different steps for each test with the samples remaining inside the loading cell. Initial analysis of the tomography images allows of the observation of the deformation of the central hole. In addition, particles manual tracking and 3D volumetric digital image correlation processing methods are considered being used to analyze the parti-cles displacements and the boundary deformation of the sample quantitatively. An unsymmetrical dam-aged zone is induced around the hole, with a reverse deformation trend being found at the boundary after unloading, which indicates that the significant anisotropic deformation of boom clay can be induced by mechanical unloading.
Anisotropic Bianchi-I universe with phantom field and cosmological constant
Indian Academy of Sciences (India)
Bikash Chandra Paul; Dilip Paul
2008-12-01
We study an anisotropic Bianchi-I universe in the presence of a phantom field and a cosmological constant. Cosmological solutions are obtained when the kinetic energy of the phantom field is of the order of anisotropy and dominates over the potential energy of the field. The anisotropy of the universe decreases and the universe transits to an isotropic flat FRW universe accommodating the present acceleration. A class of new cosmological solutions is obtained for an anisotropic universe in case an initial anisotropy exists which is bigger than the value determined by the parameter of the kinetic part of the field. Later, an autonomous system of equations for an axially symmetric Bianchi-I universe with phantom field in an exponential potential is studied. We discuss the stability of the cosmological solutions.
A Small Molecule that Induces Intrinsic Pathway Apoptosis with Unparalleled Speed
Rahul Palchaudhuri; Michael J. Lambrecht; Rachel C. Botham; Kathryn C. Partlow; Tjakko J. van Ham; Karson S. Putt; Laurie T. Nguyen; Seok-Ho Kim; Randall T. Peterson; Timothy M. Fan; Paul J. Hergenrother
2015-01-01
textabstractApoptosis is generally believed to be a process thatrequires several hours, in contrast to non-programmed forms of cell death that can occur in minutes. Our findings challenge the time-consuming nature of apoptosis as we describe the discovery and characterization of a small molecule, named Raptinal, which initiates intrinsic pathway caspase-dependent apoptosis within minutes in multiple cell lines. Comparison to a mechanistically diverse panel of apoptotic stimuli reveals that Ra...
Scaling Argument of Anisotropic Random Walk
Institute of Scientific and Technical Information of China (English)
XU Bing-Zhen; JIN Guo-Jun; WANG Fei-Feng
2005-01-01
In this paper, we analytically discuss the scaling properties of the average square end-to-end distance for anisotropic random walk in D-dimensional space ( D ≥ 2), and the returning probability Pn(ro) for the walker into a certain neighborhood of the origin. We will not only give the calculating formula for and Pn (ro), but also point out that if there is a symmetric axis for the distribution of the probability density of a single step displacement, we always obtain ～ n, where ⊥ refers to the projections of the displacement perpendicular to each symmetric axes of the walk; in D-dimensional space with D symmetric axes perpendicular to each other, we always have ～ n and the random walk will be like a purely random motion; if the number of inter-perpendicular symmetric axis is smaller than the dimensions of the space, we must have ～ n2 for very large n and the walk will be like a ballistic motion. It is worth while to point out that unlike the isotropic random walk in one and two dimensions, which is certain to return into the neighborhood of the origin, generally there is only a nonzero probability for the anisotropic random walker in two dimensions to return to the neighborhood.
Finite-difference schemes for anisotropic diffusion
Energy Technology Data Exchange (ETDEWEB)
Es, Bram van, E-mail: es@cwi.nl [Centrum Wiskunde and Informatica, P.O. Box 94079, 1090GB Amsterdam (Netherlands); FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM (Netherlands); Koren, Barry [Eindhoven University of Technology (Netherlands); Blank, Hugo J. de [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM (Netherlands)
2014-09-01
In fusion plasmas diffusion tensors are extremely anisotropic due to the high temperature and large magnetic field strength. This causes diffusion, heat conduction, and viscous momentum loss, to effectively be aligned with the magnetic field lines. This alignment leads to different values for the respective diffusive coefficients in the magnetic field direction and in the perpendicular direction, to the extent that heat diffusion coefficients can be up to 10{sup 12} times larger in the parallel direction than in the perpendicular direction. This anisotropy puts stringent requirements on the numerical methods used to approximate the MHD-equations since any misalignment of the grid may cause the perpendicular diffusion to be polluted by the numerical error in approximating the parallel diffusion. Currently the common approach is to apply magnetic field-aligned coordinates, an approach that automatically takes care of the directionality of the diffusive coefficients. This approach runs into problems at x-points and at points where there is magnetic re-connection, since this causes local non-alignment. It is therefore useful to consider numerical schemes that are tolerant to the misalignment of the grid with the magnetic field lines, both to improve existing methods and to help open the possibility of applying regular non-aligned grids. To investigate this, in this paper several discretization schemes are developed and applied to the anisotropic heat diffusion equation on a non-aligned grid.
Radial stability of anisotropic strange quark stars
Arbañil, José D. V.; Malheiro, M.
2016-11-01
The influence of the anisotropy in the equilibrium and stability of strange stars is investigated through the numerical solution of the hydrostatic equilibrium equation and the radial oscillation equation, both modified from their original version to include this effect. The strange matter inside the quark stars is described by the MIT bag model equation of state. For the anisotropy two different kinds of local anisotropic σ = pt-pr are considered, where pt and pr are respectively the tangential and the radial pressure: one that is null at the star's surface defined by pr(R) = 0, and one that is nonnull at the surface, namely, σs = 0 and σs ≠ 0. In the case σs = 0, the maximum mass value and the zero frequency of oscillation are found at the same central energy density, indicating that the maximum mass marks the onset of the instability. For the case σs ≠ 0, we show that the maximum mass point and the zero frequency of oscillation coincide in the same central energy density value only in a sequence of equilibrium configurations with the same value of σs. Thus, the stability star regions are determined always by the condition dM/dρc > 0 only when the tangential pressure is maintained fixed at the star surface's pt(R). These results are also quite important to analyze the stability of other anisotropic compact objects such as neutron stars, boson stars and gravastars.
Electrically Anisotropic Layered Perovskite Single Crystal
Li, Ting-You
2016-04-01
Organic-inorganic hybrid perovskites (OIHPs), which are promising materials for electronic and optoelectronic applications (1-10), have made into layered organic-inorganic hybrid perovskites (LOIHPs). These LOIHPs have been applied to thin-film transistors, solar cells and tunable wavelength phosphors (11-18). It is known that devices fabricated with single crystal exhibit the superior performance, which makes the growth of large-sized single crystals critical for future device applications (19-23). However, the difficulty in growing large-sized LOIHPs single crystal with superior electrical properties limits their practical applications. Here, we report a method to grow the centimeter-scaled LOIHP single crystal of [(HOC2H4NH3)2PbI4], demonstrating the potentials in mass production. After that, we reveal anisotropic electrical and optoelectronic properties which proved the carrier propagating along inorganic framework. The carrier mobility of in-inorganic-plane (in-plane) devices shows the average value of 45 cm2 V–1 s–1 which is about 100 times greater than the record of LOIHP devices (15), showing the importance of single crystal in device application. Moreover, the LOIHP single crystals show its ultra-short carrier lifetime of 42.7 ps and photoluminescence quantum efficiency (PLQE) of 25.4 %. We expect this report to be a start of LOIHPs for advanced applications in which the anisotropic properties are needed (24-25), and meets the demand of high-speed applications and fast-response applications.
Anisotropic artificial substrates for microwave applications
Shahvarpour, Attieh
The perfect electromagnetic conductor (PEMC) boundary is a novel fundamental electromagnetic concept. It is a generalized description of the electromagnetic boundary conditions including the perfect electric conductor (PEC) and the perfect magnetic conductor (PMC) and due to its fundamental properties, it has the potential of enabling several electromagnetic applications. However, the PEMC boundaries concept had remained at the theoretical level and has not been practically realized. Therefore, motivated by the importance of this electromagnetic fundamental concept and its potential applications, the first contribution of this thesis is focused on the practical implementation of the PEMC boundaries by exploiting Faraday rotation principle and ground reflection in the ferrite materials which are intrinsically anisotropic. As a result, this thesis reports the first practical approach for the realization of PEMC boundaries. A generalized scattering matrix (GSM) is used for the analysis of the grounded-ferrite PEMC boundaries structure. As an application of the PEMC boundaries, a transverse electromagnetic (TEM) waveguide is experimentally demonstrated using grounded ferrite PMC (as particular case of the PEMC boundaries) side walls. Perfect electromagnetic conductor boundaries may find applications in various types of sensors, reflectors, polarization convertors and polarization-based radio frequency identifiers. Leaky-wave antennas perform as high directivity and frequency beam scanning antennas and as a result they enable applications in radar, point-to-point communications and MIMO systems. The second contribution of this thesis is introducing and analysing a novel broadband and highly directive two-dimensional leaky-wave antenna. This antenna operates differently in the lower and higher frequency ranges. Toward its lower frequencies, it allows full-space conical-beam scanning while at higher frequencies, it provides fixed-beam radiation (at a designable angle
Smad2 is Involved in Aggregatibacter actinomycetemcomitans-induced Apoptosis
Yoshimoto, T.; Fujita, T.; Ouhara, K.; Kajiya, M.; Imai, H.; Shiba, H.; Kurihara, H.
2014-01-01
Apoptosis is thought to contribute to the progression of periodontitis. It has been suggested that the apoptosis of epithelial cells may contribute to the loss of epithelial barrier function. Smad2, a downstream signaling molecule of TGF-β receptors (TGF-βRs), is critically involved in apoptosis in several cell types. However, the relationship between smad2 and bacteria-induced apoptosis has not yet been elucidated. It is possible that the regulation of apoptosis induced by periodontopathic bacteria may lead to novel preventive therapies for periodontitis. Therefore, in the present study, we investigated the involvement of smad2 phosphorylation in apoptosis of human gingival epithelial cells induced by Aggregatibacter actinomycetemcomitans (Aa). Aa apparently induced the phosphorylation of smad2 in primary human gingival epithelial cells (HGECs) or the human gingival epithelial cell line, OBA9 cells. In addition, Aa induced phosphorylation of the serine residue of the TGF-β type I receptor (TGF-βRI) in OBA9 cells. SB431542 (a TGF-βRI inhibitor) and siRNA transfection for TGF-βRI, which reduced both TGF-βRI mRNA and protein levels, markedly attenuated the Aa-induced phosphorylation of smad2. Furthermore, the disruption of TGF-βRI signaling cascade by SB431542 and siRNA transfection for TGF-βRI abrogated the activation of cleaved caspase-3 expression and repressed apoptosis in OBA9 cells treated with Aa. Thus, Aa induced apoptosis in gingival epithelial cells by activating the TGF-βRI-smad2-caspase-3 signaling pathway. The results of the present study may suggest that the periodontopathic bacteria, Aa, activates the TGF-βR/smad2 signaling pathway in human gingival epithelial cells and induces apoptosis in epithelial cells, which may lead to new therapeutic strategies that modulate the initiation of periodontitis. PMID:25192897
DECAY OF ENERGY FOR A DISSIPATIVE ANISOTROPIC ELASTIC SYSTEM
Institute of Scientific and Technical Information of China (English)
Qin Yuming; Liu Xin; Deng Shuxian
2011-01-01
In this article, we study the large-time behavior of energy for a N-dimensional dissipative anisotropic elastic system. By means of multiplicative techniques, energy method, and Zuazua's estimate technique, we prove the decay property of energy for anisotropic elastic system.
Some Weighted Hardy-Type Inequalities on Anisotropic Heisenberg Groups
Directory of Open Access Journals (Sweden)
Yang Qiao-Hua
2011-01-01
Full Text Available We prove some weighted Hardy type inequalities associated with a class of nonisotropic Greiner-type vector fields on anisotropic Heisenberg groups. As an application, we get some new Hardy type inequalities on anisotropic Heisenberg groups which generalize a result of Yongyang Jin and Yazhou Han.
SUPERCONVERGENCE ANALYSIS OF A NONCONFORMING TRIANGULAR ELEMENT ON ANISOTROPIC MESHES
Institute of Scientific and Technical Information of China (English)
Dongyang SHI; Hui LIANG; Caixia WANG
2007-01-01
The class of anisotropic meshes we conceived abandons the regular assumption. Some distinct properties of Carey's element are used to deal with the superconvergence for a class of twodimensional second-order elliptic boundary value problems on anisotropic meshes. The optimal results are obtained and numerical examples are given to confirm our theoretical analysis.
Optical anisotropic reflectance from W720 LIPSS surface
Silvennoinen, Martti; Penttinen, Niko; Hasoň, Stanislav; Silvennoinen, Raimo
2013-05-01
Optical anisotropic reflectance from laser induced periodic surface structures (LIPSS) of stainless steel (W720LIPSS), which were produced by a femtosecond laser, were investigated by using polarized probe beam in a spectrophotometer. Remarkable repeatability in optical anisotropic reflectance was recognized.
Holographic Wilson loops in anisotropic quark-gluon plasma.
Ageev, Dmitry
2016-10-01
The nonequilibrium properties of the anisotropic quark-gluon plasma are condidered from the holographic viewpoint. Lifshitz-like solution is considered as a holographic dual of anisotropic QGP. The black brane formation in such background is considered as a thermalization in dual theory. As a probe of thermalization we consider rectangular spatial Wilson loops with different orientation.
Holographic Wilson loops in anisotropic quark-gluon plasma.
Directory of Open Access Journals (Sweden)
Ageev Dmitry
2016-01-01
Full Text Available The nonequilibrium properties of the anisotropic quark-gluon plasma are condidered from the holographic viewpoint. Lifshitz-like solution is considered as a holographic dual of anisotropic QGP. The black brane formation in such background is considered as a thermalization in dual theory. As a probe of thermalization we consider rectangular spatial Wilson loops with different orientation.
Reformulation of Nonlinear Anisotropic Crystal Elastoplasticity for Impact Physics
2015-03-01
Clayton JD, McDowell DL. Homogenized finite elastoplasticity and damage : theory and computations. Mechanics of Materials. 2004;36:799–824. 23. Clayton...ARL-TR-7231 ● MAR 2015 US Army Research Laboratory Reformulation of Nonlinear Anisotropic Crystal Elastoplasticity for Impact...of Nonlinear Anisotropic Crystal Elastoplasticity for Impact Physics by JD Clayton Weapons and Materials Research Directorate, ARL
Interpolation theory of anisotropic finite elements and applications
Institute of Scientific and Technical Information of China (English)
2008-01-01
Interpolation theory is the foundation of finite element methods.In this paper,after reviewing some existed interpolation theorems of anisotropic finite element methods,we present a new way to analyse the interpolation error of anisotropic elements based on Newton’s formula of polynomial interpolation as well as its applications.
Symmetric Periodic Solutions of the Anisotropic Manev Problem
Santoprete, Manuele
2002-01-01
We consider the Manev Potential in an anisotropic space, i.e., such that the force acts differently in each direction. Using a generalization of the Poincare' continuation method we study the existence of periodic solutions for weak anisotropy. In particular we find that the symmetric periodic orbits of the Manev system are perturbed to periodic orbits in the anisotropic problem.
Interpolation theory of anisotropic finite elements and applications
Institute of Scientific and Technical Information of China (English)
CHEN ShaoChun; XIAO LiuChao
2008-01-01
Interpolation theory is the foundation of finite element methods. In this paper, after reviewing some existed interpolation theorems of anisotropic finite element methods, we present a new way to analyse the interpolation error of anisotropic elements based on Newton's formula of polynomial interpolation as well as its applications.
THE SUPERCONVERGENCE ANALYSIS OF AN ANISOTROPIC FINITE ELEMENT
Institute of Scientific and Technical Information of China (English)
SHI Dongyang; ZHU Huiqing
2005-01-01
This paper deals with the high accuracy analysis of bilinear finite element on the class of anisotropic rectangular meshes. The inverse inequalities on anisotropic meshes are established. The superclose and the superconvergence are obtained for the second order elliptic problem. A numerical test is given, which coincides with our theoretical analysis.
Anisotropic Diffusion in Mesh-Free Numerical Magnetohydrodynamics
Hopkins, Philip F
2016-01-01
We extend recently-developed mesh-free Lagrangian methods for numerical magnetohydrodynamics (MHD) to arbitrary anisotropic diffusion equations, including: passive scalar diffusion, Spitzer-Braginskii conduction and viscosity, cosmic ray diffusion/streaming, anisotropic radiation transport, non-ideal MHD (Ohmic resistivity, ambipolar diffusion, the Hall effect), and turbulent 'eddy diffusion.' We study these as implemented in the code GIZMO for both new meshless finite-volume Godunov schemes (MFM/MFV) as well as smoothed-particle hydrodynamics (SPH). We show the MFM/MFV methods are accurate and stable even with noisy fields and irregular particle arrangements, and recover the correct behavior even in arbitrarily anisotropic cases. They are competitive with state-of-the-art AMR/moving-mesh methods, and can correctly treat anisotropic diffusion-driven instabilities (e.g. the MTI and HBI, Hall MRI). We also develop a new scheme for stabilizing anisotropic tensor-valued fluxes with high-order gradient estimators ...
Energy Technology Data Exchange (ETDEWEB)
Meng, Huan X.; Hackett, James A. [MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Nestor, Colm [MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Dunican, Donncha S.; Madej, Monika; Reddington, James P. [MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Pennings, Sari [Queen' s Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ (United Kingdom); Harrison, David J. [Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Meehan, Richard R., E-mail: Richard.Meehan@hgu.mrc.ac.uk [MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU (United Kingdom)
2011-04-01
Epigenetic mechanisms assist in maintaining gene expression patterns and cellular properties in developing and adult tissues. The molecular pathology of disease states frequently includes perturbation of DNA and histone methylation patterns, which can activate apoptotic pathways associated with maintenance of genome integrity. This perspective focuses on the pathways linking DNA methyltransferases and methyl-CpG binding proteins to apoptosis, and includes new bioinformatic analyses to characterize the evolutionary origin of two G/T mismatch-specific thymine DNA glycosylases, MBD4 and TDG.
Directory of Open Access Journals (Sweden)
Richard R. Meehan
2011-04-01
Full Text Available Epigenetic mechanisms assist in maintaining gene expression patterns and cellular properties in developing and adult tissues. The molecular pathology of disease states frequently includes perturbation of DNA and histone methylation patterns, which can activate apoptotic pathways associated with maintenance of genome integrity. This perspective focuses on the pathways linking DNA methyltransferases and methyl-CpG binding proteins to apoptosis, and includes new bioinformatic analyses to characterize the evolutionary origin of two G/T mismatch-specific thymine DNA glycosylases, MBD4 and TDG.
Anisotropic phenomena in gauge/gravity duality
Energy Technology Data Exchange (ETDEWEB)
Zeller, Hansjoerg
2014-05-26
In this thesis we use gauge/gravity duality to model anisotropic effects realised in nature. Firstly we analyse transport properties in holographic systems with a broken rotational invariance. Secondly we discuss geometries dual to IR fixed points with anisotropic scaling behaviour, which are related to quantum critical points in condensed matter systems. Gauge/gravity duality relates a gravity theory in Anti-de Sitter space to a lower dimensional strongly coupled quantum field theory in Minkowski space. Over the past decade this duality provided many insights into systems at strong coupling, e.g. quark-gluon plasma and condensed matter close to quantum critical points. One very important result computed in this framework is the value of the shear viscosity divided by the entropy density in strongly coupled theories. The quantitative result agrees very well with measurements of the ratio in quark-gluon plasma. However, for isotropic two derivative Einstein gravity it is temperature independent. We show that by breaking the rotational symmetry of a system we obtain a temperature dependent shear viscosity over entropy density. This is important to make contact with real world systems, since substances in nature display such dependence. In addition, we derive various transport properties in strongly coupled anisotropic systems using the gauge/gravity dictionary. The most notable results include an electrical conductivity with Drude behaviour in the low frequency region. This resembles conductors with broken translational invariance. However, we did not implement the breaking explicitly. Furthermore, our analysis shows that this setup models effects, resembling the piezoelectric and exoelectric effects, known from liquid crystals. In a second project we discuss a geometry with non-trivial scaling behaviour in order to model an IR fixed point of condensed matter theories. We construct the UV completion of this geometry and analyse its properties by computing the
Apoptosis Resistance in Endometriosis
Directory of Open Access Journals (Sweden)
Liselotte Mettler
2011-08-01
Full Text Available Introduction: In a cytological analysis of endometriotic lesions neither granulocytes nor cytotoxic T-cells appear in an appreciable number. Based on this observation we aimed to know, whether programmed cell death plays an essential role in the destruction of dystopic endometrium. Disturbances of the physiological mechanisms of apoptosis, a persistence of endometrial tissue could explain the disease. Another aspect of this consideration is the proliferation competence of the dystopic mucous membrane. Methods: Endometriotic lesions of 15 patients were examined through a combined measurement of apoptosis activity with the TUNEL technique (terminal deoxyribosyltransferase mediated dUTP Nick End Labeling and the proliferation activity (with the help of the Ki-67-Antigens using the monoclonal antibody Ki-S5. Results: Twelve out of 15 women studied showed a positive apoptotic activity of 3-47% with a proliferation activity of 2-25% of epithelial cells. Therefore we concluded that the persistence of dystopic endometrium requires proliferative epithelial cells from middle to lower endometrial layers. Conclusion: A dystopia misalignment of the epithelia of the upper layers of the functionalism can be rapidly eliminated by apoptotic procedures.
Ghofrani Tabari, Mehdi; Goodfellow, Sebastian; Young, R. Paul
2016-04-01
Although true-triaxial testing (TTT) of rocks is now more extensive worldwide, stress-induced heterogeneity due to the existence of several loading boundary effects is not usually accounted for and simplified anisotropic models are used. This study focuses on the enhanced anisotropic velocity structure to improve acoustic emission (AE) analysis for an enhanced interpretation of induced fracturing. Data from a TTT on a cubic sample of Fontainebleau sandstone is used in this study to evaluate the methodology. At different stages of the experiment the True-Triaxial Geophysical Imaging Cell (TTGIC), armed with an ultrasonic and AE monitoring system, performed several velocity surveys to image velocity structure of the sample. Going beyond a hydrostatic stress state (poro-elastic phase), the rock sample went through a non-dilatational elastic phase, a dilatational non-damaging elasto-plastic phase containing initial AE activity and finally a dilatational and damaging elasto-plastic phase up to the failure point. The experiment was divided into these phases based on the information obtained from strain, velocity and AE streaming data. Analysis of the ultrasonic velocity survey data discovered that a homogeneous anisotropic core in the center of the sample is formed with ellipsoidal symmetry under the standard polyaxial setup. Location of the transducer shots were improved by implementation of different velocity models for the sample starting from isotropic and homogeneous models going toward anisotropic and heterogeneous models. The transducer shot locations showed a major improvement after the velocity model corrections had been applied especially at the final phase of the experiment. This location improvement validated our velocity model at the final phase of the experiment consisting lower-velocity zones bearing partially saturated fractures. The ellipsoidal anisotropic velocity model was also verified at the core of the cubic rock specimen by AE event location of
Creating Statistically Anisotropic and Inhomogeneous Perturbations
Armendariz-Picon, C
2007-01-01
In almost all structure formation models, primordial perturbations are created within a homogeneous and isotropic universe, like the one we observe. Because their ensemble averages inherit the symmetries of the spacetime in which they are seeded, cosmological perturbations then happen to be statistically isotropic and homogeneous. Certain anomalies in the cosmic microwave background on the other hand suggest that perturbations do not satisfy these statistical properties, thereby challenging perhaps our understanding of structure formation. In this article we relax this tension. We show that if the universe contains an appropriate triad of scalar fields with spatially constant but non-zero gradients, it is possible to generate statistically anisotropic and inhomogeneous primordial perturbations, even though the energy momentum tensor of the triad itself is invariant under translations and rotations.
Transient motion of thick anisotropic plates
Nayfeh, Adnan H.; Taylor, Timothy W.
1991-01-01
Analyses are developed for the response of anisotropic plate strips to a transient load. The load is taken in the form of a line load of normal stress on the surface or within the body of the strip. The characteristic free vibrational modes of the strip are derived and used to derive the secular equation for this case in closed form and to isolate the mathematical conditions for symmetric and antisymmetric wave mode propagation in completely separate terms. The applied loads are expanded in terms of these normal modes and the response of the plate is obtained by superposition of the appropriate components. Material systems of higher symmetry are contained implicitly in the analysis.
Anisotropic Cloth Modeling for Material Fabric
Zhang, Mingmin; Pan, Zhigengx; Mi, Qingfeng
Physically based cloth simulation has been challenging the graphics community for more than three decades. With the developing of virtual reality and clothing CAD, it has become the key technique of virtual garment and try-on system. Although it has received considerable attention in computer graphics, due to its flexible property and realistic feeling that the textile engineers pay much attention to, there is not a successful methodology to simulate cloth both in visual realism and physical accuracy. We present a new anisotropic textile modeling method based on physical mass-spring system, which models the warps and wefts separately according to the different material fabrics. The simulation process includes two main steps: firstly the rigid object simulation and secondly the flexible mass simulation near to be equilibrium. A multiresolution modeling is applied to enhance the tradeoff fruit of the realistic presentation and computation cost. Finally, some examples and the analysis results show the efficiency of the proposed method.
Anisotropic compact stars in Karmarkar spacetime
Singh, Ksh Newton; Govender, M
2016-01-01
We present a new class of solutions to the Einstein field equations for an anisotropic matter distribution in which the interior space-time obeys the Karmarkar condition. The necessary and sufficient condition required for a spherically symmetric space-time to be of class one reduces the gravitational behavior of the model to a single metric function. By assuming a physically viable form for the $g_{rr}$ metric potential we obtain an exact solution of the Einstein field equations which is free from any singularities and satisfies all the physical criteria. We utilize this solution to predict the masses and radii of well-known compact objects such as Cen X-3, PSR J0348+0432, PSRB0943+10 and XTE J1739-285. To be publish in Chinese Physics C (Accepted)
Plasmons in Anisotropic Quark-Gluon Plasma
Carrington, Margaret E; Mrowczynski, Stanislaw
2014-01-01
Plasmons of quark-gluon plasma - gluon collective modes - are systematically studied. The plasma is, in general, non-equilibrium but homogeneous. We consider anisotropic momentum distributions of plasma constituents which are obtained from the isotropic one by stretching or squeezing in one direction. This leads to prolate or oblate distributions, respectively. We study all possible degrees of one dimensional deformation from the extremely prolate case, when the momentum distribution is infinitely elongated in one direction, to the extremely oblate distribution, which is infinitely squeezed in the same direction. In between these extremes we discuss arbitrarily prolate, weakly prolate, isotropic, weakly oblate and arbitrarily oblate distributions. For each case, the number of modes is determined using a Nyquist analysis and the complete spectrum of plasmons is found analytically if possible, and numerically when not. Unstable modes are shown to exist in all cases except that of isotropic plasma. We derive con...
Anisotropic magnetic fluctuations in 3-k antiferromagnets
Energy Technology Data Exchange (ETDEWEB)
Caciuffo, R. [European Commission, Joint Research Center, Institute for Transuranium Elements, Postfach 2340, Karlsruhe D-76125 (Germany)]. E-mail: roberto.caciuffo@ec.europa.eu; Magnani, N. [European Commission, Joint Research Center, Institute for Transuranium Elements, Postfach 2340, Karlsruhe D-76125 (Germany); Istituto dei Materiali per l' Elettronica ed il Magnetismo, Consiglio Nazionale delle Ricerche, I-43010 Fontanini (PR) (Italy); Santini, P. [Dipartimento di Fisica, Universita di Parma, Viale G. P. Usberti 7/A, I-43100 Parma (Italy); Carretta, S. [Dipartimento di Fisica, Universita di Parma, Viale G. P. Usberti 7/A, I-43100 Parma (Italy); Amoretti, G. [Dipartimento di Fisica, Universita di Parma, Viale G. P. Usberti 7/A, I-43100 Parma (Italy); Blackburn, E. [European Commission, Joint Research Center, Institute for Transuranium Elements, Postfach 2340, Karlsruhe D-76125 (Germany); Institute Laue-Langevin, Boite Postal 156-X, F-38042 Grenoble Cedex (France); Enderle, M. [Institute Laue-Langevin, Boite Postal 156-X, F-38042 Grenoble Cedex (France); Brown, P.J. [Institute Laue-Langevin, Boite Postal 156-X, F-38042 Grenoble Cedex (France); Lander, G.H. [European Commission, Joint Research Center, Institute for Transuranium Elements, Postfach 2340, Karlsruhe D-76125 (Germany)
2007-03-15
The anisotropy of magnetic fluctuations propagating along the high-symmetry directions in cubic systems with 3-k magnetic order is analyzed within the random-phase approximation assuming anisotropic exchange interactions. Both transverse and longitudinal structures are considered, with reference to the UO{sub 2} and USb compounds, respectively. In the case of UO{sub 2}, the spin-waves polarizations calculated for acoustic and optical branches are favorably compared with three-dimensional polarization analysis experiments carried out on a triple axis spectrometer. The overall spin-waves polarization behavior emerges as a consequence of the 3-k nature of the magnetic order, whatever the strength of the exchange coupling assumed.
Transport processes in anisotropic gravitational collapse
Martínez, J
1996-01-01
In this paper we introduce a new method to study the influence of thermal conduction and viscous processes in anisotropic gravitational collapse. To this end we employ the HJR method to solve the Einstein equations. The Maxwell-Cattaneo type transport equations are used to find the temperature and bulk and shear viscous pressures. Under some conditions Maxwell-Cattaneo transport equations comply with relativistic causality. Thus, it is advisable to use them instead of Eckart transport equations. In the inner layers of the star the temperature ceases to be sensitive to the boundary condition. This behavior, which can be explained in terms of the Eddington approximation, allows us to find the thickness of the neutrinosphere. The dynamics of collapsing dense stars is deeply influenced by the neutrino emission/absorption processes. These cool the star and drive it to a new equilibrium state. Therefore, the calculation of transport coefficients is based on these processes.
Particle Behavior at Anisotropically Curved Liquid Interfaces
McEnnis, Kathleen; Zeng, Chuan; Davidovitch, Benny; Dinsmore, Anthony; Russell, Thomas
2011-03-01
A particle bound to an anisotropically curved liquid interface, such as a cylinder or catenoid, cannot maintain a constant contact angle without deforming the interface. Theory suggests that the particles will experience a force that depends on the interfacial shape and migrate to minimize the total interfacial energy. To test these predictions, particles were deposited on top of liquid semi-cylinders of ionic liquid or melted polystyrene confined on chemically patterned surfaces. Particles were also deposited on liquid catenoid structures created by placing a melted polymer film under an electric field. The location of the particles on these structures was observed by optical, confocal, and scanning electron microscopy. The implications for the directed assembly of particles and stability of Pickering emulsions are also discussed.
Recent developments in anisotropic heterogeneous shell theory
Grigorenko, Alexander Ya; Grigorenko, Yaroslav M; Vlaikov, Georgii G
2016-01-01
This volume focuses on the relevant general theory and presents some first applications, namely those based on classical shell theory. After a brief introduction, during which the history and state-of-the-art are discussed, the first chapter presents the mechanics of anisotropic heterogeneous shells, covering all relevant assumptions and the basic relations of 3D elasticity, classical and refined shell models. The second chapter examines the numerical techniques that are used, namely discrete orthogonalization, spline-collocation and Fourier series, while the third highlights applications based on classical theory, in particular, the stress-strain state of shallow shells, non-circular shells, shells of revolution, and free vibrations of conical shells. The book concludes with a summary and an outlook bridging the gap to the second volume.
Anisotropic dynamic mass density for fluidsolid composites
Wu, Ying
2012-10-01
By taking the low frequency limit of multiple-scattering theory, we obtain the dynamic effective mass density of fluidsolid composites with a two-dimensional rectangular lattice structure. The anisotropic mass density can be described by an angle-dependent dipole solution, to the leading-order of solid concentration. The angular dependence vanishes for the square lattice, but at high solid concentrations there is a structure-dependent factor that contributes to the leading-order solution. In all cases, Woods formula is found to be accurately valid for the effective bulk modulus, independent of the structures. Numerical evaluations from the solutions are shown to be in excellent agreement with finite-element simulations. © 2012 Elsevier B.V.
Anisotropic turbulence in weakly stratified rotating magnetoconvection
Giesecke, A
2010-01-01
Numerical simulations of the 3D MHD-equations that describe rotating magnetoconvection in a Cartesian box have been performed using the code NIRVANA. The characteristics of averaged quantities like the turbulence intensity and the turbulent heat flux that are caused by the combined action of the small-scale fluctuations are computed. The correlation length of the turbulence significantly depends on the strength and orientation of the magnetic field and the anisotropic behavior of the turbulence intensity induced by Coriolis and Lorentz force is considerably more pronounced for faster rotation. The development of isotropic behavior on the small scales -- as it is observed in pure rotating convection -- vanishes even for a weak magnetic field which results in a turbulent flow that is dominated by the vertical component. In the presence of a horizontal magnetic field the vertical turbulent heat flux slightly increases with increasing field strength, so that cooling of the rotating system is facilitated. Horizont...
A model for anisotropic strange stars
Deb, Debabrata; Ray, Saibal; Rahaman, Farook; Guha, B K
2016-01-01
We attempt to find a singularity free interior solution for a neutral and static stellar model. We consider that (i) the star is made up of anisotropic fluid and (ii) the MIT bag model can be used. The total system is defined by assuming the density profile given by Mak and Harko \\cite{Mak2002}, which satisfies all the physical conditions of a stellar system and is stable by nature. We find that those stellar systems which obey such a non-linear density function must have maximum anisotropy at the surface. We also perform several tests for physical features of the proposed model and show that these are mostly acceptable within certain range. As a special mention, from our investigation we find that the maximum mass and radius of the quark star are $11.811 km$ and $3.53 {M}_{\\odot}$ respectively.
Anisotropic criteria for the type of superconductivity
Energy Technology Data Exchange (ETDEWEB)
Kogan, Vladimir G [Ames Laboratory; Prozorov, Ruslan [Ames Laboratory
2014-08-01
The classical criterion for classification of superconductors as type I or type II based on the isotropic Ginzburg-Landau theory is generalized to arbitrary temperatures for materials with anisotropic Fermi surfaces and order parameters. We argue that the relevant quantity for this classification is the ratio of the upper and thermodynamic critical fields Hc2/Hc, rather than the traditional ratio of the penetration depth and the coherence length λ/ξ. Even in the isotropic case, Hc2/Hc coincides with 2√λ/ξ only at the critical temperature Tc and they differ as T decreases, the long-known fact. Anisotropies of Fermi surfaces and order parameters may amplify this difference and render false the criterion based on the value of κ=λ/ξ.
An Anisotropic Hardening Model for Springback Prediction
Zeng, Danielle; Xia, Z. Cedric
2005-08-01
As more Advanced High-Strength Steels (AHSS) are heavily used for automotive body structures and closures panels, accurate springback prediction for these components becomes more challenging because of their rapid hardening characteristics and ability to sustain even higher stresses. In this paper, a modified Mroz hardening model is proposed to capture realistic Bauschinger effect at reverse loading, such as when material passes through die radii or drawbead during sheet metal forming process. This model accounts for material anisotropic yield surface and nonlinear isotropic/kinematic hardening behavior. Material tension/compression test data are used to accurately represent Bauschinger effect. The effectiveness of the model is demonstrated by comparison of numerical and experimental springback results for a DP600 straight U-channel test.
Anisotropic plasmas from axion and dilaton deformations
Donos, Aristomenis; Sosa-Rodriguez, Omar
2016-01-01
We construct black hole solutions of type IIB supergravity that are holographically dual to anisotropic plasmas arising from deformations of an infinite class of four-dimensional CFTs. The CFTs are dual to $AdS_5\\times X_5$, where $X_5$ is an Einstein manifold, and the deformations involve the type IIB axion and dilaton, with non-trivial periodic dependence on one of the spatial directions of the CFT. At low temperatures the solutions approach smooth domain wall solutions with the same $AdS_5\\times X_5$ solution appearing in the far IR. For sufficiently large deformations an intermediate scaling regime appears which is governed by a Lifshitz-like scaling solution. We calculate the DC thermal conductivity and some components of the shear viscosity tensor.
Theory of Random Anisotropic Magnetic Alloys
DEFF Research Database (Denmark)
Lindgård, Per-Anker
1976-01-01
A mean-field-crystal-field theory is developed for random, multicomponent, anisotropic magnetic alloys. It is specially applicable to rare-earth alloys. A discussion is given of multicritical points and phase transitions between various states characterized by order parameters with different...... spatial directions or different ordering wave vectors. Theoretical predictions based on known parameters for the phase diagrams and magnetic moments for the binary rare-earth alloys of Tb, Dy, Ho, and Er, Tb-Tm, Nd-Pr, and pure double-hcp Nd agree qualitatively with the experimental observations....... Quantitative agreement can be obtained by increasing the interaction between different alloy elements, in particular for alloys with very different axial anisotropy, e.g., Tb-Tm. A model system consisting of a singlet-singlet and singlet-doublet alloy is discussed in detail. A simple procedure to include...
Anisotropic plasmas from axion and dilaton deformations
Donos, Aristomenis; Gauntlett, Jerome P.; Sosa-Rodriguez, Omar
2016-11-01
We construct black hole solutions of type IIB supergravity that are holographically dual to anisotropic plasmas arising from deformations of an infinite class of four-dimensional CFTs. The CFTs are dual to AdS 5 × X 5, where X 5 is an Einstein manifold, and the deformations involve the type IIB axion and dilaton, with non-trivial periodic dependence on one of the spatial directions of the CFT. At low temperatures the solutions approach smooth domain wall solutions with the same AdS 5 × X 5 solution appearing in the far IR. For sufficiently large deformations an intermediate scaling regime appears which is governed by a Lifshitz-like scaling solution. We calculate the DC thermal conductivity and some components of the shear viscosity tensor.
Spectral functions from anisotropic lattice QCD
Aarts, G.; Allton, C.; Amato, A.; Evans, W.; Giudice, P.; Harris, T.; Kelly, A.; Kim, S. Y.; Lombardo, M. P.; Praki, K.; Ryan, S. M.; Skullerud, J.-I.
2016-12-01
The FASTSUM collaboration has been carrying out lattice simulations of QCD for temperatures ranging from one third to twice the crossover temperature, investigating the transition region, as well as the properties of the Quark Gluon Plasma. In this contribution we concentrate on quarkonium correlators and spectral functions. We work in a fixed scale scheme and use anisotropic lattices which help achieving the desirable fine resolution in the temporal direction, thus facilitating the (ill posed) integral transform from imaginary time to frequency space. We contrast and compare results for the correlators obtained with different methods, and different temporal spacings. We observe robust features of the results, confirming the sequential dissociation scenario, but also quantitative differences indicating that the methods' systematic errors are not yet under full control. We briefly outline future steps towards accurate results for the spectral functions and their associated statistical and systematic errors.
Anisotropic metamaterials with simultaneous attenuation and amplification
Mackay, Tom G
2015-01-01
Anisotropic metamaterials that are neither wholly dissipative nor wholly active at a specific frequency are permitted by classical electromagnetic theory. Well-established formalisms for the homogenization of particulate composite materials indicate that such a metamaterial may be conceptualized quite simply as a random mixture of electrically small spheroidal particles of at least two different isotropic dielectric materials, one of which must be dissipative but the other active. The realization of this metametarial is influenced by the volume fraction, spatial distribution, particle shape and size, and the relative permittivities of the component materials. Metamaterials displaying both dissipation and amplification at the same frequency with more complicated linear as well as nonlinear constitutive properties are possible.
Mean field magnetization of gapped anisotropic multiplet
Paixão, L. S.; Reis, M. S.
2014-06-01
Some materials have a large gap between the ground and first excited states. At temperatures smaller than the gap value, the thermodynamic properties of such materials are mainly ruled by the ground state. It is also common to find materials with magnetocrystalline anisotropy, which arises due to interatomic interactions. The present paper uses a classical approach to deal large angular momenta in such materials. Based on analytical expressions for the thermodynamics of paramagnetic gapped anisotropic multiplets, we use mean field theory to study the influence of the anisotropy upon the properties of interacting systems. We also use Landau theory to determine the influence of the anisotropy in first and second order phase transitions. It is found that the anisotropy increases the critical temperature, and enlarges the hysteresis of first order transitions. We present analytical expressions for the quantities analyzed.
Anisotropic criteria for the type of superconductivity
Kogan, V. G.; Prozorov, R.
2014-08-01
The classical criterion for classification of superconductors as type I or type II based on the isotropic Ginzburg-Landau theory is generalized to arbitrary temperatures for materials with anisotropic Fermi surfaces and order parameters. We argue that the relevant quantity for this classification is the ratio of the upper and thermodynamic critical fields Hc2/Hc, rather than the traditional ratio of the penetration depth and the coherence length λ /ξ. Even in the isotropic case, Hc2/Hc coincides with √2 λ /ξ only at the critical temperature Tc and they differ as T decreases, the long-known fact. Anisotropies of Fermi surfaces and order parameters may amplify this difference and render false the criterion based on the value of κ =λ/ξ.
Translation correlations in anisotropically scattering media
Judkewitz, Benjamin; Vellekoop, Ivo M; Yang, Changhuei
2014-01-01
Controlling light propagation across scattering media by wavefront shaping holds great promise for a wide range of applications in biomedical imaging. However finding the right wavefront to shape is a challenge when the scattering transmission matrix is not known. Correlations in transmission matrices, especially the so-called memory-effect, have been exploited to address this limitation. However, the traditional memory-effect applies to thin scattering layers at a distance from the target, which precludes its use within thick scattering media. Here, we report on analogous transmission matrix correlations within thick anisotropically scattering media, with wide-ranging implications for biomedical imaging. We use a simple conceptual framework to explain these findings and relate them to the traditional memory effect.
Long-range interaction of anisotropic systems
Zhang, Junyi
2015-02-01
The first-order electrostatic interaction energy between two far-apart anisotropic atoms depends not only on the distance between them but also on their relative orientation, according to Rayleigh-Schrödinger perturbation theory. Using the first-order interaction energy and the continuum model, we study the long-range interaction between a pair of parallel pristine graphene sheets at zero temperature. The asymptotic form of the obtained potential density, &epsi:(D) &prop: ?D ?3 ?O(D?4), is consistent with the random phase approximation and Lifshitz theory. Accordingly, neglectance of the anisotropy, especially the nonzero first-order interaction energy, is the reason why the widely used Lennard-Jones potential approach and dispersion corrections in density functional theory give a wrong asymptotic form ε(D) &prop: ?D?4. © EPLA, 2015.
Effective orthorhombic anisotropic models for wavefield extrapolation
Ibanez-Jacome, W.
2014-07-18
Wavefield extrapolation in orthorhombic anisotropic media incorporates complicated but realistic models to reproduce wave propagation phenomena in the Earth\\'s subsurface. Compared with the representations used for simpler symmetries, such as transversely isotropic or isotropic, orthorhombic models require an extended and more elaborated formulation that also involves more expensive computational processes. The acoustic assumption yields more efficient description of the orthorhombic wave equation that also provides a simplified representation for the orthorhombic dispersion relation. However, such representation is hampered by the sixth-order nature of the acoustic wave equation, as it also encompasses the contribution of shear waves. To reduce the computational cost of wavefield extrapolation in such media, we generate effective isotropic inhomogeneous models that are capable of reproducing the firstarrival kinematic aspects of the orthorhombic wavefield. First, in order to compute traveltimes in vertical orthorhombic media, we develop a stable, efficient and accurate algorithm based on the fast marching method. The derived orthorhombic acoustic dispersion relation, unlike the isotropic or transversely isotropic ones, is represented by a sixth order polynomial equation with the fastest solution corresponding to outgoing P waves in acoustic media. The effective velocity models are then computed by evaluating the traveltime gradients of the orthorhombic traveltime solution, and using them to explicitly evaluate the corresponding inhomogeneous isotropic velocity field. The inverted effective velocity fields are source dependent and produce equivalent first-arrival kinematic descriptions of wave propagation in orthorhombic media. We extrapolate wavefields in these isotropic effective velocity models using the more efficient isotropic operator, and the results compare well, especially kinematically, with those obtained from the more expensive anisotropic extrapolator.
Cardiovascular molecular imaging of apoptosis
Energy Technology Data Exchange (ETDEWEB)
Wolters, S.L.; Reutelingsperger, C.P.M. [Maastricht University, Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht (Netherlands); Corsten, M.F.; Hofstra, L. [Maastricht University, Department of Cardiology, Cardiovascular Research Institute Maastricht, P.O. Box 616, Maastricht (Netherlands); Narula, J. [University of California Irvine, Department of Cardiology, Irvine (United States)
2007-06-15
Molecular imaging strives to visualise processes at the molecular and cellular level in vivo. Understanding these processes supports diagnosis and evaluation of therapeutic efficacy on an individual basis and thereby makes personalised medicine possible. Apoptosis is a well-organised mode of cell suicide that plays a role in cardiovascular diseases (CVD). Apoptosis is associated with loss of cardiomyocytes following myocardial infarction, atherosclerotic plaque instability, congestive heart failure and allograft rejection of the transplanted heart. Thus, apoptosis constitutes an attractive target for molecular imaging of CVD. Our current knowledge about the molecular players and mechanisms underlying apoptosis offers a rich palette of potential molecular targets for molecular imaging. However, only a few have been successfully developed so far. This review highlights aspects of the molecular machinery and biochemistry of apoptosis relevant to the development of molecular imaging probes. It surveys the role of apoptosis in four major areas of CVD and portrays the importance and future perspectives of apoptosis imaging. The annexin A5 imaging protocol is emphasised since it is the most advanced protocol to measure apoptosis in both preclinical and clinical studies. (orig.)
Apoptosis : Target of cancer therapy
Ferreira, CG; Epping, M; Kruyt, FAE; Giaccone, G
2002-01-01
Recent knowledge on apoptosis has made it possible to devise novel approaches, which exploit this process to treat cancer. In this review, we discuss in detail approaches to induce tumor cell apoptosis, their mechanism of action, stage of development, and possible drawbacks. Finally, the obstacles y
On the Schrodinger equations with isotropic and anisotropic fourth-order dispersion
Directory of Open Access Journals (Sweden)
Elder J. Villamizar-Roa
2016-01-01
Full Text Available This article concerns the Cauchy problem associated with the nonlinear fourth-order Schrodinger equation with isotropic and anisotropic mixed dispersion. This model is given by the equation $$ i\\partial_tu+\\epsilon \\Delta u+\\delta A u+\\lambda|u|^\\alpha u=0,\\quad x\\in\\mathbb{R}^{n},\\; t\\in \\mathbb{R}, $$ where A is either the operator $\\Delta^2$ (isotropic dispersion or $\\sum_{i=1}^d\\partial_{x_ix_ix_ix_i}$, $1\\leq d
Noxa couples lysosomal membrane permeabilization and apoptosis during oxidative stress.
Eno, Colins O; Zhao, Guoping; Venkatanarayan, Avinashnarayan; Wang, Bing; Flores, Elsa R; Li, Chi
2013-12-01
The exact roles of lysosomal membrane permeabilization (LMP) in oxidative stress-triggered apoptosis are not completely understood. Here, we first studied the temporal relation between LMP and mitochondrial outer membrane permeabilization (MOMP) during the initial stage of apoptosis caused by the oxidative stress inducer H2O2. Despite its essential role in mediating apoptosis, the expression of the BH3-only Bcl-2 protein Noxa was dispensable for LMP. In contrast, MOMP was dependent on Noxa expression and occurred downstream of LMP. When lysosomal membranes were stabilized by the iron-chelating agent desferrioxamine, H2O2-induced increase in DNA damage, Noxa expression, and subsequent apoptosis were abolished by the inhibition of LMP. Importantly, LMP-induced Noxa expression increase was mediated by p53 and seems to be a unique feature of apoptosis caused by oxidative stress. Finally, exogenous iron loading recapitulated the effects of H2O2 on the expression of BH3-only Bcl-2 proteins. Overall, these data reveal a Noxa-mediated signaling pathway that couples LMP with MOMP and ultimate apoptosis during oxidative stress.
Apoptosis Evaluation by Electrochemical Techniques.
Yin, Jian; Miao, Peng
2016-03-01
Apoptosis has close relevance to pathology, pharmacology, and toxicology. Accurate and convenient detection of apoptosis would be beneficial for biological study, clinical diagnosis, and drug development. Based on distinct features of apoptotic cells, a diversity of analytical techniques have been exploited for sensitive analysis of apoptosis, such as surface plasmon resonance, electrochemical methods, flow cytometry, and some imaging assays. Among them, the features of simplicity, easy operation, low cost, and high sensitivity make electrochemical techniques powerful tools to investigate electron-transfer processes of in vitro biological systems. In this contribution, a general overview of current knowledge on various technical approaches for apoptosis evaluation is provided. Furthermore, recently developed electrochemical biosensors for detecting apoptotic cells and their advantages over traditional methods are summarized. One of the main considerations focuses on designing the recognition elements based on various biochemical events during apoptosis.
Caspase Family Proteases and Apoptosis
Institute of Scientific and Technical Information of China (English)
Ting-Jun FAN; Li-Hui HAN; Ri-Shan CONG; Jin LIANG
2005-01-01
Apoptosis, or programmed cell death, is an essential physiological process that plays a critical role in development and tissue homeostasis. The progress of apoptosis is regulated in an orderly way by a series of signal cascades under certain circumstances. The caspase-cascade system plays vital roles in the induction, transduction and amplification of intracellular apoptotic signals. Caspases, closely associated with apoptosis, are aspartate-specific cysteine proteases and members of the interleukin-1β-converting enzyme family. The activation and function of caspases, involved in the delicate caspase-cascade system, are regulated by various kinds of molecules, such as the inhibitor of apoptosis protein, Bcl-2 family proteins, calpain,and Ca2+. Based on the latest research, the members of the caspase family, caspase-cascade system and caspase-regulating molecules involved in apoptosis are reviewed.
Synthesis of anisotropic nanoparticles by seeded emulsion polymerization.
Mock, Eric B; De Bruyn, Hank; Hawkett, Brian S; Gilbert, Robert G; Zukoski, Charles F
2006-04-25
Anisotropic polystyrene nanoparticles of diameters below 0.5 microm were prepared by coating the surface of cross-linked polystyrene latex particles with a thin hydrophilic polymer layer prior to swelling the particles with styrene and then initiating second-stage free-radical polymerization. Conditions were found so that all particles had uniform asymmetry. The effect of surface chemistry on the development of particle anisotropy during seeded emulsion polymerization of sub-0.5 microm diameter particles was studied. The extent and uniformity of the anisotropy of the final particles depended strongly on the presence of the hydrophilic surface coating. Systematic variation of the degree of hydrophilicity of the surface coating provided qualitative insight into the mechanism responsible for anisotropy. Conditions were chosen so that the surface free energy favored the extrusion of a hydrophobic bulge of monomer on the hydrophilic surface of the particle during the swelling phase: the presence of a hydrophilic layer on the particle surface causes this asymmetry to be favored above uniform wetting of the particle surface by the monomer. Kinetic effects, arising from the finite time required for the seed to swell with the monomer, also play a role.
Prediction of Brittle Failure for TBM Tunnels in Anisotropic Rock: A Case Study from Northern Norway
Dammyr, Øyvind
2016-06-01
Prediction of spalling and rock burst is especially important for hard rock TBM tunneling, because failure can have larger impact than in a drill and blast tunnel and ultimately threaten excavation feasibility. The majority of research on brittle failure has focused on rock types with isotropic behavior. This paper gives a review of existing theory and its application before a 3.5-m-diameter TBM tunnel in foliated granitic gneiss is used as a case to study brittle failure characteristics of anisotropic rock. Important aspects that should be considered in order to predict brittle failure in anisotropic rock are highlighted. Foliation is responsible for considerable strength anisotropy and is believed to influence the preferred side of v-shaped notch development in the investigated tunnel. Prediction methods such as the semi- empirical criterion, the Hoek- Brown brittle parameters, and the non-linear damage initiation and spalling limit method give reliable results; but only as long as the angle between compression axis and foliation in uniaxial compressive tests is relevant, dependent on the relation between tunnel trend/plunge, strike/dip of foliation, and tunnel boundary stresses. It is further demonstrated that local in situ stress variations, for example, due to the presence of discontinuities, can have profound impact on failure predictions. Other carefully documented case studies into the brittle failure nature of rock, in particular anisotropic rock, are encouraged in order to expand the existing and relatively small database. This will be valuable for future TBM planning and construction stages in highly stressed brittle anisotropic rock.
Then, C; Stassen, B; Depta, K; Silber, G
2017-02-21
Mechanical characterization of human superficial facial tissue has important applications in biomedical science, computer assisted forensics, graphics, and consumer goods development. Specifically, the latter may include facial hair removal devices. Predictive accuracy of numerical models and their ability to elucidate biomechanically relevant questions depends on the acquisition of experimental data and mechanical tissue behavior representation. Anisotropic viscoelastic behavioral characterization of human facial tissue, deformed in vivo with finite strain, however, is sparse. Employing an experimental-numerical approach, a procedure is presented to evaluate multidirectional tensile properties of superficial tissue layers of the face in vivo. Specifically, in addition to stress relaxation, displacement-controlled multi-step ramp-and-hold protocols were performed to separate elastic from inelastic properties. For numerical representation, an anisotropic hyperelastic material model in conjunction with a time domain linear viscoelasticity formulation with Prony series was employed. Model parameters were inversely derived, employing finite element models, using multi-criteria optimization. The methodology provides insight into mechanical superficial facial tissue properties. Experimental data shows pronounced anisotropy, especially with large strain. The stress relaxation rate does not depend on the loading direction, but is strain-dependent. Preconditioning eliminates equilibrium hysteresis effects and leads to stress-strain repeatability. In the preconditioned state tissue stiffness and hysteresis insensitivity to strain rate in the applied range is evident. The employed material model fits the nonlinear anisotropic elastic results and the viscoelasticity model reasonably reproduces time-dependent results. Inversely deduced maximum anisotropic long-term shear modulus of linear elasticity is G∞,max(aniso)=2.43kPa and instantaneous initial shear modulus at an
Quantization of the radiation field in an anisotropic dielectric medium
Institute of Scientific and Technical Information of China (English)
Li Wei; Liu Shi-Bing; Yang Wei
2009-01-01
There are both loss and dispersion characteristics for most dielectric media. In quantum theory the loss in medium is generally described by Langevin force in the Langevin noise (LN) scheme by which the quantization of the radiation field in various homogeneous absorbing dielectrics can be successfully actualized. However, it is invalid for the anisotropic dispersion medium. This paper extends the LN theory to an anisotropic dispersion medium and presented the quantization of the radiation field as well as the transformation relation between the homogeneous and anisotropic dispersion media.
Q-factor and absorption enhancement for plasmonic anisotropic nanoparticles
Liu, Wei; Miroshnichenko, Andrey E
2016-01-01
We investigate the scattering and absorption properties of anisotropic metal-dielectric core-shell nanoparticles. It is revealed that the radially anisotropic dielectric layer can accelerate the evanescent decay of the localized resonant surface modes, leading to Q-factor and absorption rate enhancement. Moreover, the absorption cross section can be maximized to reach the single resonance absorption limit. We further show that such artificial anisotropic cladding materials can be realized by isotropic layered structures, which may inspire many applications based on scattering and absorption of plasmonic nanoparticles.
Magnetic Anisotropic Energy Gap and Strain Effect in Au Nanoparticles
Directory of Open Access Journals (Sweden)
Shih Po-Hsun
2009-01-01
Full Text Available Abstract We report on the observation of the size effect of thermal magnetization in Au nanoparticles. The thermal deviation of the saturation magnetization departs substantially from that predicted by the Bloch T3/2-law, indicating the existence of magnetic anisotropic energy. The results may be understood using the uniaxial anisotropy Heisenberg model, in which the surface atoms give rise to polarized moments while the magnetic anisotropic energy decreases as the size of the Au nanoparticles is reduced. There is a significant maximum magnetic anisotropic energy found for the 6 nm Au nanoparticles, which is associated with the deviation of the lattice constant due to magnetocrystalline anisotropy.
Design of anisotropic reflector with birefringent thin films
Institute of Scientific and Technical Information of China (English)
Jianguo Wang; Kui Yi; Jianda Shao; Zhengxiu Fan
2005-01-01
A novel design for dielectric anisotropic mirrors with birefringent thin films for normal incidence is presented. This mirror consists of a stack of quarter-wave biaxial layers. The biaxial anisotropic layers can be fabricated by oblique deposition. The reflectance is different for two linear polarizations of light incidence on the mirrors. As a numerical example, the design is carried out on glass with TiO2 and ZrO2. These thin films could be applied to anisotropic reflective devices for lasers.
Development of laser ablation plasma by anisotropic self-radiation
Directory of Open Access Journals (Sweden)
Ohnishi Naofumi
2013-11-01
Full Text Available We have proposed a method for reproducing an accurate solution of low-density ablation plasma by properly treating anisotropic radiation. Monte-Carlo method is employed for estimating Eddington tensor with limited number of photon samples in each fluid time step. Radiation field from ablation plasma is significantly affected by the anisotropic Eddington tensor. Electron temperature around the ablation surface changes with the radiation field and is responsible for the observed emission. An accurate prediction of the light emission from the laser ablation plasma requires a careful estimation of the anisotropic radiation field.
Electrochemical Impedance of a Battery Electrode with Anisotropic Active Particles
Song, J
2013-01-01
Electrochemical impedance spectra for battery electrodes are usually interpreted using models that assume isotropic active particles, having uniform current density and symmetric diffusivities. While this can be reasonable for amorphous or polycrystalline materials with randomly oriented grains, modern electrode materials increasingly consist of highly anisotropic, single-crystalline, nanoparticles, with different impedance characteristics. In this paper, analytical expressions are derived for the impedance of anisotropic particles with tensorial diffusivities and orientation-dependent surface reaction rates and capacitances. The resulting impedance spectrum contains clear signatures of the anisotropic material properties and aspect ratio, as well as statistical variations in any of these parameters.
BIGH3 protein and macrophages in retinal endothelial cell apoptosis.
Mondragon, Albert A; Betts-Obregon, Brandi S; Moritz, Robert J; Parvathaneni, Kalpana; Navarro, Mary M; Kim, Hong Seok; Lee, Chi Fung; LeBaron, Richard G; Asmis, Reto; Tsin, Andrew T
2015-01-01
Diabetes is a pandemic disease with a higher occurrence in minority populations. The molecular mechanism to initiate diabetes-associated retinal angiogenesis remains largely unknown. We propose an inflammatory pathway of diabetic retinopathy in which macrophages in the diabetic eye provide TGFβ to retinal endothelial cells (REC) in the retinal microvasculature. In response to TGFβ, REC synthesize and secrete a pro-apoptotic BIGH3 (TGFβ-Induced Gene Human Clone 3) protein, which acts in an autocrine loop to induce REC apoptosis. Rhesus monkey retinal endothelial cells (RhREC) were treated with dMCM (cell media of macrophages treated with high glucose and LDL) and assayed for apoptosis (TUNEL), BIGH3 mRNA (qPCR), and protein (Western blots) expressions. Cells were also treated with ΤGFβ1 and 2 for BIGH3 mRNA and protein expression. Inhibition assays were carried out using antibodies for TGFβ1 and for BIGH3 to block apoptosis and mRNA expression. BIGH3 in cultured RhREC cells were identified by immunohistochemistry (IHC). Distribution of BIGH3 and macrophages in the diabetic mouse retina was examined with IHC. RhRECs treated with dMCM or TGFβ showed a significant increase in apoptosis and BIGH3 protein expression. Recombinant BIGH3 added to RhREC culture medium led to a dose-dependent increase in apoptosis. Antibodies (Ab) directed against BIGH3 and TGFβ, as well as TGFβ receptor blocker resulted in a significant reduction in apoptosis induced by either dMCM, TGFβ or BIGH3. IHC showed that cultured RhREC constitutively expressed BIGH3. Macrophage and BIGH3 protein were co-localized to the inner retina of the diabetic mouse eye. Our results support a novel inflammatory pathway for diabetic retinopathy. This pathway is initiated by TGFβ released from macrophages, which promotes synthesis and release of BIGH3 protein by REC and REC apoptosis.
Apoptosis in Primary Hyperparathyroidism.
Segiet, Oliwia Anna; Mielańczyk, Łukasz; Piecuch, Adam; Michalski, Marek; Tyczyński, Szczepan; Brzozowa-Zasada, Marlena; Deska, Mariusz; Wojnicz, Romuald
2017-03-31
Primary hyperparathyroidism (PHPT) is defined by inappropriate elevation of parathormone, caused by parathyroid hyperplasia, also known as multi-gland disease (MGD), parathyroid adenoma (PA), or parathyroid carcinoma (PC). Although several studies have already been conducted, there is a lack of a definite diagnostic marker, which could unambiguously distinguish MGD from PA or PC. The accurate and prompt diagnosis has the key meaning for effective treatment and follow-up. This review paper presents the role of apoptosis in PHPT. The comparison of the expression of Fas, TRAIL, BCL-2 family members, p53 in MGD, PA, and PC, among others, was described. The expression of described factors varies among proliferative lesions of parathyroid gland; therefore, these could serve as additional markers to assist in the diagnosis.
DEFF Research Database (Denmark)
Wanitchakool, Podchanart; Ousingsawat, Jiraporn; Sirianant, Lalida
2016-01-01
, and cystic fibrosis transmembrane conductance regulator (CFTR) in cellular apoptosis. LRRC8A-E has been identified as a volume-regulated anion channel expressed in many cell types. It was shown to be required for regulatory and apoptotic volume decrease (RVD, AVD) in cultured cell lines. Its presence also......(-) channels or as regulators of other apoptotic Cl(-) channels, such as LRRC8. CFTR has been known for its proapoptotic effects for some time, and this effect may be based on glutathione release from the cell and increase in cytosolic reactive oxygen species (ROS). Although we find that CFTR is activated...... by cell swelling, it is possible that CFTR serves RVD/AVD through accumulation of ROS and activation of independent membrane channels such as ANO6. Thus activation of ANO6 will support cell shrinkage and induce additional apoptotic events, such as membrane phospholipid scrambling....
Experimental Characterization and Micromechanical Modelling of Anisotropic Slates
Chen, Yi-Feng; Wei, Kai; Liu, Wu; Hu, Shao-Hua; Hu, Ran; Zhou, Chuang-Bing
2016-09-01
Laboratory tests were performed in this study to examine the anisotropic physical and mechanical properties of the well-foliated Jiujiang slate. The P-wave velocity and the apparent Young's modulus were found to increase remarkably with the foliation angle θ, and the compressive strength at any confining pressure varies in a typical U-shaped trend, with the maximum strength consistently attained at θ = 90° and the minimum strength at θ = 45°. The slate samples failed in three typical patterns relevant to the foliation angle, i.e. shear failure across foliation planes for θ ≤ 15°, sliding along foliation planes for 30° ≤ θ ≤ 60° and axial splitting along foliation planes for θ = 90°. The stress-strain curves at any given foliation angle and confining pressure display an initial nonlinear phase, a linear elastic phase, a crack initiation and growth phase, as well as a rapid stress drop phase and a residual stress phase. Based on the experimental evidences, a micromechanical damage-friction model was proposed for the foliated slate by simply modelling the foliation planes as a family of elastic interfaces and by characterizing the interaction between the foliation planes and the rock matrix with a nonlinear damage evolution law associated with the inclination angle. The proposed model was applied to predict the deformational and strength behaviours of the foliated slate under triaxial compressive conditions using the material parameters calibrated with the uniaxial and/or triaxial test data, with good agreement between the model predictions and the laboratory measurements.
Carbonized-leaf Membrane with Anisotropic Surfaces for Sodium-ion Battery.
Li, Hongbian; Shen, Fei; Luo, Wei; Dai, Jiaqi; Han, Xiaogang; Chen, Yanan; Yao, Yonggang; Zhu, Hongli; Fu, Kun; Hitz, Emily; Hu, Liangbing
2016-01-27
A simple one-step thermal pyrolysis route has been developed to prepare carbon membrane from a natural leaf. The carbonized leaf membrane possesses anisotropic surfaces and internal hierarchical porosity, exhibiting a high specific capacity of 360 mAh/g and a high initial Coulombic efficiency of 74.8% as a binder-free, current-collector-free anode for rechargeable sodium ion batteries. Moreover, large-area carbon membranes with low contact resistance are fabricated by simply stacking and carbonizing leaves, a promising strategy toward large-scale sodium-ion battery developments.
Weibel instability driven by spatially anisotropic density structures
Tomita, Sara
2016-01-01
Observations of afterglows of gamma-ray bursts suggest (GRBs) that post-shock magnetic fields are strongly amplified to about 100 times the shock-compressed value. The Weibel instability appears to play an important role in generating of the magnetic field. However, recent simulations of collisionless shocks in homogeneous plasmas show that the magnetic field generated by the Weibel instability rapidly decays. There must be some density fluctuations in interstellar and circumstellar media. The density fluctuations are anisotropically compressed in the downstream region of relativistic shocks. In this paper, we study the Weibel instability in electron--positron plasmas with the spatially anisotropic density distributions by means of two-dimensional particle-in-cell simulations. We find that large magnetic fields are maintained for a longer time by the Weibel instability driven by the spatially anisotropic density structure. Particles anisotropically escape from the high density region, so that the temperature ...
Anisotropic thermal conduction in galaxy clusters with MHD in Gadget
Arth, Alexander; Beck, Alexander M; Petkova, Margarita; Lesch, Harald
2014-01-01
We present an implementation of thermal conduction including the anisotropic effects of magnetic fields for SPH. The anisotropic thermal conduction is mainly proceeding parallel to magnetic fields and suppressed perpendicular to the fields. We derive the SPH formalism for the anisotropic heat transport and solve the corresponding equation with an implicit conjugate gradient scheme. We discuss several issues of unphysical heat transport in the cases of extreme ansiotropies or unmagnetized regions and present possible numerical workarounds. We implement our algorithm into the GADGET code and study its behaviour in several test cases. In general, we reproduce the analytical solutions of our idealised test problems, and obtain good results in cosmological simulations of galaxy cluster formations. Within galaxy clusters, the anisotropic conduction produces a net heat transport similar to an isotropic Spitzer conduction model with an efficiency of one per cent. In contrast to isotropic conduction our new formalism ...
Modelling of anisotropic compact stars of embedding class one
Energy Technology Data Exchange (ETDEWEB)
Bhar, Piyali [Government General Degree College, Department of Mathematics, Singur, Hooghly, West Bengal (India); Maurya, S.K. [University of Nizwa, Department of Mathematical and Physical Sciences, College of Arts and Science, Nizwa (Oman); Gupta, Y.K. [Raj Kumar Goel Institute of Technology, Department of Mathematics, Ghaziabad, U.P. (India); Manna, Tuhina [St. Xavier' s College, Department of Commerce (Evening), Kolkata, West Bengal (India)
2016-10-15
In the present article, we have constructed static anisotropic compact star models of Einstein field equations for the spherical symmetric metric of embedding class one. By assuming the particular form of the metric function ν, we have solved the Einstein field equations for anisotropic matter distribution. The anisotropic models represent the realistic compact objects such as SAX J 1808.4-3658 (SS1), Her X-1, Vela X-12, PSR J1614-2230 and Cen X-3. We have reported our results in details for the compact star Her X-1 on the ground of physical properties such as pressure, density, velocity of sound, energy conditions, TOV equation and red-shift etc. Along with these, we have also discussed about the stability of the compact star models. Finally we made a comparison between our anisotropic stars with the realistic objects on the key aspects as central density, central pressure, compactness and surface red-shift. (orig.)
Numerical study of domain coarsening in anisotropic stripe patterns.
Boyer, Denis
2004-06-01
We study the coarsening of two-dimensional smectic polycrystals characterized by grains of oblique stripes with only two possible orientations. For this purpose, an anisotropic Swift-Hohenberg equation is solved. For quenches close enough to the onset of stripe formation, the average domain size increases with time as t(1/2). Further from onset, anisotropic pinning forces similar to Peierls stresses in solid crystals slow down defects, and growth becomes anisotropic. In a wide range of quench depths, dislocation arrays remain mobile and dislocation density roughly decays as t(-1/3), while chevron boundaries are totally pinned. We discuss some agreements and disagreements found with recent experimental results on the coarsening of anisotropic electroconvection patterns.
The Nature of Primordial Fluctuations from Anisotropic Inflation
Watanabe, Masa-aki; Soda, Jiro
2010-01-01
We study the statistical nature of primordial fluctuations from an anisotropic inflation which is realized by a vector field coupled to an inflaton. We find a suitable gauge, which we call the canonical gauge, for anisotropic inflation by generalizing the flat slicing gauge in conventional isotropic inflation. Using the canonical gauge, we reveal the structure of the couplings between curvature perturbations, vector waves, and gravitational waves. We identify two sources of anisotropy, i.e. the anisotropy due to the anisotropic expansion of the universe and that due to the anisotropic couplings among variables. It turns out that the latter effect is dominant. Since the coupling between the curvature perturbations and vector waves is the strongest one, the statistical anisotropy in the curvature perturbations is larger than that in gravitational waves. We find the cross correlation between the curvature perturbations and gravitational waves which never occurs in conventional inflation. We also find the linear ...
An engineered anisotropic nanofilm with unidirectional wetting properties
Malvadkar, Niranjan A.; Hancock, Matthew J.; Sekeroglu, Koray; Dressick, Walter J.; Demirel, Melik C.
2010-12-01
Anisotropic textured surfaces allow water striders to walk on water, butterflies to shed water from their wings and plants to trap insects and pollen. Capturing these natural features in biomimetic surfaces is an active area of research. Here, we report an engineered nanofilm, composed of an array of poly(p-xylylene) nanorods, which demonstrates anisotropic wetting behaviour by means of a pin-release droplet ratchet mechanism. Droplet retention forces in the pin and release directions differ by up to 80μN, which is over ten times greater than the values reported for other engineered anisotropic surfaces. The nanofilm provides a microscale smooth surface on which to transport microlitre droplets, and is also relatively easy to synthesize by a bottom-up vapour-phase technique. An accompanying comprehensive model successfully describes the film's anisotropic wetting behaviour as a function of measurable film morphology parameters.
Numerical study of the thermal degradation of isotropic and anisotropic polymeric materials
Energy Technology Data Exchange (ETDEWEB)
Soler, E. [Departamento de Lenguajes y Ciencias de la Computacion, ETSI Informatica, Universidad de Malaga, 29071 Malaga (Spain); Ramos, J.I. [Room I-320-D, ETS Ingenieros Industriales, Universidad de Malaga, Plaza El Ejido, s/n, 29013 Malaga (Spain)
2005-08-01
The thermal degradation of two-dimensional isotropic, orthotropic and anisotropic polymeric materials is studied numerically by means of a second-order accurate (in both space and time) linearly implicit finite difference formulation which results in linear algebraic equations at each time step. It is shown that, for both isotropic and orthotropic composites, the monomer mass diffusion tensor plays a role in initiating the polymerization kinetics, the formation of a polymerization kernel and the initial front propagation, whereas the later stages of the polymerization are nearly independent of the monomer mass diffusion tensor. In anisotropic polymeric composites, it has been found that the monomer mass diffusion tensor plays a paramount role in determining the initial stages of the polymerization and the subsequent propagation of the polymerization front, the direction and speed of propagation of which are found to be related to the principal directions of both the monomer mass and the heat diffusion tensors. It is also shown that the polymerization time and temperatures depend strongly on the anisotropy of the mass and heat diffusion tensors. (authors)
Galperin, Boris; Hoemann, Jesse; Espa, Stefania; Di Nitto, Gabriella; Lacorata, Guglielmo
2016-12-01
Turbulence with inverse energy cascade and its transport properties are investigated experimentally in a flow associated with a westward propagating jet. Turbulence and the jet were produced by an electromagnetic force in a rotating tank filled with an electrolytic saline solution. The parabolic free surface emulated the topographic β effect which evoked the zonation. The spectral and transport flow characteristics were highly anisotropic. Turbulence is diagnosed by exploring the analogy between vertical and horizontal turbulent overturns in, respectively, stably stratified and quasigeostrophic flows which gives rise to a method of potential vorticity (PV) monotonizing. The anisotropization of transport properties of the flow is investigated using the finite scale Lyapunov exponent technique. After initial exponential particle separation, radial (meridional in geophysical and planetary applications) diffusion attains a short-ranged Richardson regime which transitions to the Taylor (scale-independent diffusivity) one. The azimuthal (zonal) diffusion exhibits a double-plateau structure which attains a superdiffusive regime on large scales. The transition to the Taylor regime for the radial diffusion takes place at a scale of turbulence anisotropization. The radial eddy diffusivity in both regimes as well as the transition scale are all determined by the rate of the inverse energy cascade, ɛ , that can be diagnosed by the PV monotonizing. Conversely, ɛ can be deduced from the scale of the Richardson-Taylor regime transition in the radial eddy diffusivity which, thus, provides an additional tool of diagnosing anisotropic macroturbulence with inverse energy cascade.
Galperin, Boris; Hoemann, Jesse; Espa, Stefania; Di Nitto, Gabriella; Lacorata, Guglielmo
2016-12-01
Turbulence with inverse energy cascade and its transport properties are investigated experimentally in a flow associated with a westward propagating jet. Turbulence and the jet were produced by an electromagnetic force in a rotating tank filled with an electrolytic saline solution. The parabolic free surface emulated the topographic β effect which evoked the zonation. The spectral and transport flow characteristics were highly anisotropic. Turbulence is diagnosed by exploring the analogy between vertical and horizontal turbulent overturns in, respectively, stably stratified and quasigeostrophic flows which gives rise to a method of potential vorticity (PV) monotonizing. The anisotropization of transport properties of the flow is investigated using the finite scale Lyapunov exponent technique. After initial exponential particle separation, radial (meridional in geophysical and planetary applications) diffusion attains a short-ranged Richardson regime which transitions to the Taylor (scale-independent diffusivity) one. The azimuthal (zonal) diffusion exhibits a double-plateau structure which attains a superdiffusive regime on large scales. The transition to the Taylor regime for the radial diffusion takes place at a scale of turbulence anisotropization. The radial eddy diffusivity in both regimes as well as the transition scale are all determined by the rate of the inverse energy cascade, ε, that can be diagnosed by the PV monotonizing. Conversely, ε can be deduced from the scale of the Richardson-Taylor regime transition in the radial eddy diffusivity which, thus, provides an additional tool of diagnosing anisotropic macroturbulence with inverse energy cascade.
Neutron transport with anisotropic scattering: theory and applications
Van den Eynde, Gert
2005-01-01
This thesis is a blend of neutron transport theory and numerical analysis. We start with the study of the problem of the Mika/Case eigenexpansion used in the solution process of the homogeneous one-speed Boltzmann neutron transport equation with anisotropic scattering for plane symmetry. The anisotropic scattering is expressed as a finite Legendre series in which the coefficients are the ``scattering coefficients'. This eigenexpansion consists of a discrete spectrum of eigenvalues with its co...
ON THE ANISOTROPIC ACCURACY ANALYSIS OF ACM'S NONCONFORMING FINITE ELEMENT
Institute of Scientific and Technical Information of China (English)
Dong-yang Shi; Shi-peng Mao; Shao-chun Chen
2005-01-01
The main aim of this paper is to study the superconvergence accuracy analysis of the famous ACM's nonconforming finite element for biharmonic equation under anisotropic meshes. By using some novel approaches and techniques, the optimal anisotropic interpolation error and consistency error estimates are obtained. The global error is of order O(h2). Lastly, some numerical tests are presented to verify the theoretical analysis.
Holographic study of the jet quenching parameter in anisotropic systems
Energy Technology Data Exchange (ETDEWEB)
Wang, Luying [Shanghai University, Department of Physics, Shanghai (China); Wu, Shang-Yu [National Chiao Tung University, Department of Electrophysics, Hsinchu (China)
2016-11-15
We first calculate the jet quenching parameter of an anisotropic plasma with a U(1) chemical potential via AdS/CFT duality. The effects of charge, anisotropy parameter, and quark motion direction on the jet quenching parameter are investigated. We then discuss the situation of an anisotropic black brane in the IR region. We study both the jet quenching parameters along the longitudinal direction and the transverse plane. (orig.)
Wave propagation and radiation in gyrotropic and anisotropic media
Eroglu, Abdullah
2010-01-01
""Wave Propagation and Radiation in Gyrotropic and Anisotropic Media"" fills the gap in the area of applied electromagnetics for the design of microwave and millimeter wave devices using composite structures where gyrotropic, anisotropic materials are used. The book provides engineers with the information on theory and practical skills they need to understand wave propagation and radiation characteristics of materials and the ability to design devices at higher frequencies with optimum device performance.
Duals of Orphan-Free Anisotropic Voronoi Diagrams are Triangulations
Canas, Guillermo D
2011-01-01
We show that, under mild conditions on the underlying metric, duals of appropriately defined anisotropic Voronoi diagrams are embedded triangulations. Furthermore, they always triangulate the convex hull of the vertices, and have other properties that parallel those of ordinary Delaunay triangulations. These results apply to the duals of anisotropic Voronoi diagrams of any set of vertices, so long as the diagram is orphan-free.
Modeling and Measurements of CMUTs with Square Anisotropic Plates
DEFF Research Database (Denmark)
la Cour, Mette Funding; Christiansen, Thomas Lehrmann; Dahl-Petersen, Christian;
2013-01-01
The conventional method of modeling CMUTs use the isotropic plate equation to calculate the deflection, leading to deviations from FEM simulations including anisotropic effects of around 10% in center deflection. In this paper, the deflection is found for square plates using the full anisotropic...... plate equation and the Galerkin method. Utilizing the symmetry of the silicon crystal, a compact and accurate expression for the deflection can be obtained. The deviation from FEM in center deflection is
Anisotropic static solutions in modelling highly compact bodies
Indian Academy of Sciences (India)
M Chaisi; S D Maharaj
2006-03-01
Einstein field equations for static anisotropic spheres are solved and exact interior solutions obtained. This paper extends earlier treatments to include anisotropic models which accommodate a wider variety of physically viable energy densities. Two classes of solutions are possible. The first class contains the limiting case ∝ -2 for the energy density which arises in many astrophysical applications. In the second class the singularity at the centre of the star is not present in the energy density
Holographic study on the jet quenching parameter in anisotropic systems
Wang, Luying
2016-01-01
We first calculate the jet quenching parameter of an anisotropic plasma with a U(1) chemical potential via the AdS/CFT duality. The effects of charge, anisotropy parameter and quark motion direction on the jet quenching parameter are investigated. We then discuss the situation of anisotropic black brane in the IR region. We study both the jet quenching parameters along the longitudinal direction and transverse plane.
Hybrid anisotropic materials for wind power turbine blades
Golfman, Yosif
2012-01-01
Based on rapid technological developments in wind power, governments and energy corporations are aggressively investing in this natural resource. Illustrating some of the crucial new breakthroughs in structural design and application of wind energy generation machinery, Hybrid Anisotropic Materials for Wind Power Turbine Blades explores new automated, repeatable production techniques that expand the use of robotics and process controls. These practices are intended to ensure cheaper fabrication of less-defective anisotropic material composites used to manufacture power turbine blades. This boo
Biomimetic collagen scaffolds with anisotropic pore architecture.
Davidenko, N; Gibb, T; Schuster, C; Best, S M; Campbell, J J; Watson, C J; Cameron, R E
2012-02-01
Sponge-like matrices with a specific three-dimensional structural design resembling the actual extracellular matrix of a particular tissue show significant potential for the regeneration and repair of a broad range of damaged anisotropic tissues. The manipulation of the structure of collagen scaffolds using a freeze-drying technique was explored in this work as an intrinsically biocompatible way of tailoring the inner architecture of the scaffold. The research focused on the influence of temperature gradients, imposed during the phase of crystallisation of collagen suspensions, upon the degree of anisotropy in the microstructures of the scaffolds produced. Moulding technology was employed to achieve differences in heat transfer rates during the freezing processes. For this purpose various moulds with different configurations were developed with a view to producing uniaxial and multi-directional temperature gradients across the sample during this process. Scanning electron microscopy analysis of different cross-sections (longitudinal and horizontal) of scaffolds revealed that highly aligned matrices with axially directed pore architectures were obtained where single unidirectional temperature gradients were induced. Altering the freezing conditions by the introduction of multiple temperature gradients allowed collagen scaffolds to be produced with complex pore orientations, and anisotropy in pore size and alignment.
Lattice Study of Anisotropic QED-3
Hands, S; Hands, Simon; Thomas, Iorwerth Owain
2004-01-01
We present results from a Monte Carlo simulation of non-compact lattice QED in 3 dimensions on a $16^3$ lattice in which an explicit anisotropy between $x$ and $y$ hopping terms has been introduced into the action. This formulation is inspired by recent formulations of anisotropic QED$_3$ as an effective theory of the non-superconducting portion of the cuprate phase diagram, with relativistic fermion degrees of freedom defined near the nodes of the gap function on the Fermi surface, and massless photon degrees of freedom reproducing the dynamics of the phase disorder of the superconducting order parameter. Using a parameter set corresponding to broken chiral symmetry in the isotropic limit, our results show that the renormalised anisotropy, defined in terms of the ratio of correlation lengths of gauge invariant bound states in the $x$ and $y$ directions, exceeds the explicit anisotropy $\\kappa$ introduced in the lattice action, implying in contrast to recent analytic results that anisotropy is a relevant defo...
Coefficient adaptive triangulation for strongly anisotropic problems
Energy Technology Data Exchange (ETDEWEB)
D`Azevedo, E.F.; Romine, C.H.; Donato, J.M.
1996-01-01
Second order elliptic partial differential equations arise in many important applications, including flow through porous media, heat conduction, the distribution of electrical or magnetic potential. The prototype is the Laplace problem, which in discrete form produces a coefficient matrix that is relatively easy to solve in a regular domain. However, the presence of anisotropy produces a matrix whose condition number is increased, making the resulting linear system more difficult to solve. In this work, we take the anisotropy into account in the discretization by mapping each anisotropic region into a ``stretched`` coordinate space in which the anisotropy is removed. The region is then uniformly triangulated, and the resulting triangulation mapped back to the original space. The effect is to generate long slender triangles that are oriented in the direction of ``preferred flow.`` Slender triangles are generally regarded as numerically undesirable since they tend to cause poor conditioning; however, our triangulation has the effect of producing effective isotropy, thus improving the condition number of the resulting coefficient matrix.
Details of tetrahedral anisotropic mesh adaptation
Jensen, Kristian Ejlebjerg; Gorman, Gerard
2016-04-01
We have implemented tetrahedral anisotropic mesh adaptation using the local operations of coarsening, swapping, refinement and smoothing in MATLAB without the use of any for- N loops, i.e. the script is fully vectorised. In the process of doing so, we have made three observations related to details of the implementation: 1. restricting refinement to a single edge split per element not only simplifies the code, it also improves mesh quality, 2. face to edge swapping is unnecessary, and 3. optimising for the Vassilevski functional tends to give a little higher value for the mean condition number functional than optimising for the condition number functional directly. These observations have been made for a uniform and a radial shock metric field, both starting from a structured mesh in a cube. Finally, we compare two coarsening techniques and demonstrate the importance of applying smoothing in the mesh adaptation loop. The results pertain to a unit cube geometry, but we also show the effect of corners and edges by applying the implementation in a spherical geometry.
Salmonella typhimurium Invasion Induces Apoptosis in Infected Macrophages
Monack, Denise M.; Raupach, Barbel; Hromockyj, Alexander E.; Falkow, Stanley
1996-09-01
Invasive Salmonella typhimurium induces dramatic cytoskeletal changes on the membrane surface of mammalian epithelial cells and RAW264.7 macrophages as part of its entry mechanism. Noninvasive S. typhimurium strains are unable to induce this membrane ruffling. Invasive S. typhimurium strains invade RAW264.7 macrophages in 2 h with 7- to 10-fold higher levels than noninvasive strains. Invasive S. typhimurium and Salmonella typhi, independent of their ability to replicate intracellularly, are cytotoxic to RAW264.7 macrophages and, to a greater degree, to murine bone marrow-derived macrophages. Here, we show that the macrophage cytotoxicity mediated by invasive Salmonella is apoptosis, as shown by nuclear morphology, cytoplasmic vacuolization, and host cell DNA fragmentation. S. typhimurium that enter cells causing ruffles but are mutant for subsequent intracellular replication also initiate host cell apoptosis. Mutant S. typhimurium that are incapable of inducing host cell membrane ruffling fail to induce apoptosis. The activation state of the macrophage plays a significant role in the response of macrophages to Salmonella invasion, perhaps indicating that the signal or receptor for initiating programmed cell death is upregulated in activated macrophages. The ability of Salmonella to promote apoptosis may be important for the initiation of infection, bacterial survival, and escape of the host immune response.
Protooncogenes as mediators of apoptosis.
Teng, C S
2000-01-01
Apoptosis has been well established as a vital biological phenomenon that is important in the maintenance of cellular homeostasis. Three major protooncogene families and their encoded proteins function as mediators of apoptosis in various cell types and are the subject of this chapter. Protooncogenic proteins such as c-Myc/Max, c-Fos/c-Jun, and Bcl-2/Bax utilize a synergetic effect to enhance their roles in the pro- or antiapoptotic action. These family members activate and repress the expression of their target genes, control cell cycle progression, and execute programmed cell death. Repression or overproduction of these protooncogenic proteins induces apoptosis, which may vary as a result of either cell type specificity or the nature of the apoptotic stimuli. The proapoptotic and antiapoptotic proteins exert their effects in the membrane of cellular organelles. Here they generate cell-type-specific signals that activate the caspase family of proteases and their regulators for the execution of apoptosis.
Invertebrate Iridovirus Modulation of Apoptosis
Institute of Scientific and Technical Information of China (English)
Trevor Williams; Nllesh S. Chitnis; Sh(a)n L. Bilimoria
2009-01-01
Programmed cell death (apoptosis) is a key host response to virus infection. Viruses that can modulate host apoptotic responses are likely to gain important opportunities for transmission. Here we review recent studies that demonstrate that particles of Invertebrate iridescent virus 6 (IIV-6) (Iridoviridae, genus Iridovirus), or an IIV-6 virion protein extract, are capable of inducing apoptosis in lepidopteran and coleopteran cells, at concentrations 1000-fold lower than that required to shut-off host macromolecular synthesis. Induction of apoptosis depends on endocytosis of one or more heat-sensitive virion component(s). Studies with a JNK inh ibitor(SP600125) indicated that the JNK signaling pathway is significantly involved in apoptosis in IIV-6 infections of Choristoneurafumiferana ceils. The genome of IIV-6 codes for an inhibitor of apoptosis iap gene (193R) that encodes a protein of 208 aa with 15% identity and 28% similarity in its amino acid sequence to IAP-3 from Cydia pomonella ganulovirus (CpGV). Transcription of IIV-6 iap did not require prior DNA or protein synthesis, indicating that it is an immediate-early class gene. Transient expression and gene knockdown studies have confirmed the functional nature of the IIV-6 iap gene. We present a tentative model for IIV-6 induction and inhibition of apoptosis in insect cells and discuss the potential applications of these findings in insect pest control.
Caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress.
Zhang, Qiang; Liu, Jianing; Chen, Shulan; Liu, Jing; Liu, Lijuan; Liu, Guirong; Wang, Fang; Jiang, Wenxin; Zhang, Caixia; Wang, Shuangyu; Yuan, Xiao
2016-04-01
It is well recognized that mandibular growth, which is caused by a variety of functional appliances, is considered to be the result of both neuromuscular and skeletal adaptations. Accumulating evidence has demonstrated that apoptosis plays an important role in the adaptation of skeletal muscle function. However, the underlying mechanism of apoptosis that is induced by stretch continues to be incompletely understood. Endoplasmic reticulum stress (ERS), a newly defined signaling pathway, initiates apoptosis. This study seeks to determine if caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress in myoblast and its underlying mechanism. Apoptosis was assessed by Hochest staining, DAPI staining and annexin V binding and PI staining. ER chaperones, such as GRP78, CHOP and caspase-12, were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Furthermore, caspase-12 inhibitor was used to value the mechanism of the caspase-12 pathway. Apoptosis of myoblast, which is subjected to cyclic stretch, was observed in a time-dependent manner. We found that GRP78 mRNA and protein were significantly increased and CHOP and caspase-12 were activated in myoblast that was exposed to cyclic stretch. Caspase-12 inhibition reduced stretch-induced apoptosis, and caspase-12 activated caspase-3 to induce apoptosis. We concluded that caspase-12 played an important role in stretch-induced apoptosis that is associated by endoplasmic reticulum stress by activating caspase-3.
Serial Serum Leukocyte Apoptosis Levels as Predictors of Outcome in Acute Traumatic Brain Injury
Directory of Open Access Journals (Sweden)
Hung-Chen Wang
2014-01-01
Full Text Available Background. Apoptosis associates with secondary brain injury after traumatic brain injury (TBI. This study posits that serum leukocyte apoptosis levels in acute TBI are predictive of outcome. Methods. Two hundred and twenty-nine blood samples from 88 patients after acute TBI were obtained on admission and on Days 4 and 7. Serial apoptosis levels of different leukocyte subsets were examined in 88 TBI patients and 27 control subjects. Results. The leukocyte apoptosis was significantly higher in TBI patients than in controls. Brief unconsciousness (P=0.009, motor deficits (P≤0.001, GCS (P≤0.001, ISS (P=0.001, WBC count (P=0.015, late apoptosis in lymphocytes and monocytes on Day 1 (P=0.004 and P=0.022, resp., subdural hemorrhage on initial brain CT (P=0.002, neurosurgical intervention (P≤0.001, and acute posttraumatic seizure (P=0.046 were significant risk factors of outcome. Only motor deficits (P=0.033 and late apoptosis in monocytes on Day 1 (P=0.037 were independently associated with outcome. A cutoff value of 5.72% of late apoptosis in monocytes was associated with poor outcome in acute TBI patients. Conclusion. There are varying degrees of apoptosis in patients following TBI and in healthy individuals. Such differential expression suggests that apoptosis in different leukocyte subsets plays an important role in outcome following injury.
p63 is required beside p53 for PERP-mediated apoptosis in uveal melanoma
Awais, Raheela; Spiller, David G; White, Michael R H; Paraoan, Luminita
2016-01-01
Background: PERP (p53 apoptosis effector related to PMP-22), a transcriptional target of p53, is downregulated and contributes to the impairment of apoptosis in uveal melanoma (UM). Intriguingly, PERP is not induced in UM despite functional p53. p63, located on chromosome 3, which is characteristically altered in high-risk UM, can transactivate PERP. Here, we determine the functional role of p63 expression in the initiation of p53/PERP-mediated apoptosis in UM. Methods: PERP expression was monitored by quantitative PCR (qPCR) and immunoblotting in UM cell lines treated with DNA-damaging agents. The functional role of p63 was assessed by transient expression of p63-turbo GFP (p63-tGFP) in the apoptosis- resistant, 3q-deficient OCM-1 cells. Expression and localisation of p63, PERP and p53, and induction of apoptosis were characterised by qPCR, immunoblotting and live cell confocal microscopy. Results: PERP expression was significantly downregulated in all UM cell lines. DNA-damaging treatments failed to induce apoptosis and activate PERP in OCM-1 cells, which displayed non-functional levels of p63. Expression of p63-tGFP induced apoptosis with marked increase in PERP expression and associated p53 accumulation. Conclusions: Lack of p63 contributes to reduced PERP levels and impaired p53-mediated apoptosis in UM. p63 expression is required for PERP-mediated apoptosis in UM. PMID:27584665
Advance research in apoptosis mediating by death receptor
Institute of Scientific and Technical Information of China (English)
JI Yu-bin; LIU Hong-juan; JI Chen-feng; ZHANG He
2008-01-01
Apoptosis is one of the main types of programmed cell deaths (PCD) and involves a series of biochemical events that lead to a variety of morphological changes and death. The initial and progress of apoptosis is precisely regulated. This review will summarize current knowledge of the signal transduction pathways of apoptosis. It is now well-established that the apoptotic signals generally involve the extrinsic or intrinsic pathways of apoptosis. The extrinsic pathway originates at the membrane and engages cell surface death receptors whereas the intrinsic pathway predominantly involves mitochondria. In the intrinsic pathway, the cell death signal induced changes of mitochondrial membrane permeability and the loss of membrane potential. Many proteins factors released, and then cytoplasmic cytochrome C and easpase-9 form of apoptosis. The activated caspase-9 cut caspase-3, then cell dead at last. In the case of extrinsic pathway, several death receptors exist including Fas, TNFR-1, DR3, DR4, DR5 and DR6. These death receptors contain an intracellular region of approximately 80 amino acids that is designated as "death domain". The death domain is an important structure that plays a key role in the transduction of apoptotic signals. The interaction between Fas and its ligand (FasL) triggers the formation of a death-inducing signaling complex (DISC), which subsequently recruits and activates caspase-8; this in turn activates other procaspases and culminates in the cleavage of cellular substrates and apoptosis. During the process of tumor cell lines apoptosis Inducted by chemotherapy. It is easy to see the increasing of the Fas receptors and inducing of FasL expression, it can inhibite apoptosis when the blocking Fas / FasL. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a type Ⅱ transmembrane protein belonging to the TNF family of death ligands. TRAIL has been suggested as a safe and tumorselective anticancer agent with low toxicity to normal
Safrole oxide induces apoptosis by activating caspase-3, -8, and -9 in A549 human lung cancer cells.
Du, Aiying; Zhao, Baoxiang; Yin, Deling; Zhang, Shangli; Miao, Junying
2006-01-01
Previously we found that 3,4-(methylenedioxy)-1-(2',3'-epoxypropyl)-benzene (safrole oxide) induced a typical apoptosis in A549 human lung cancer cells. In this study, we further investigated which caspases were activated by safrole oxide during the apoptosis. The data showed that the activity of caspase-3, -8, and -9 was significantly enhanced by the compound, which suggested that safrole oxide might be used as a caspase promoter to initiate lung cancer cell apoptosis.
Fracture Interface Waves in an Anisotropic Medium
Pyrak-Nolte, L. J.; Shao, S.; Abell, B.
2011-12-01
The detection of fractures in an anisotropic medium is complicated by discreet modes that are guided or confined by fractures and that travel with velocities close (~92%) to the shear wave velocity. For instance, fractures can mask the presence of textural anisotropy in a rock, and can increase the apparent shear wave velocity anisotropy. In this study, we examine how fracture interface waves affect the interpretation of shear wave velocities for two orthogonal polarizations propagating parallel to the layers. Samples with textural anisotropy measuring 100 x 100 x 100 mm were fabricated from garolite, an epoxy - cloth laminate, with layer thickness on the order of 0.5 mm. Three fracture samples were created with: (1) a fracture oriented parallel to layering, (2) a fracture oriented perpendicular to layering, and (3) two intersecting orthogonal fractures. An intact sample without fractures was used a standard. A seismic array, consisting of source and receiver arrays, was used to perform full waveform measurements. Each array contained two compressional and five shear wave piezoelectric contact transducers with a central frequency of 1 MHz. Shear wave transducers were polarized both perpendicular and parallel to the layering as well as to the fracture. Measurements were made for a range of stresses (0.4 - 4MPa). When the shear wave was polarized parallel to a fracture, the shear wave traveled at the bulk shear velocity respective to the layering. However, when the shear wave was polarized perpendicular to a fracture, the measured velocity ranged between the Rayleigh wave velocity at low stress and the bulk shear wave at high stress. The shear wave velocities perpendicular and parallel to the layering (propagation direction parallel to the layers) were ~1500 m/s and ~1600 m/s, respectively, in the intact sample. However, in the fractured samples, the observed shear wave anisotropy depended on the stress and fracture orientation relative to the layering. When the
PURCELL EFFECT IN EXTREMELY ANISOTROPIC ELLIPTIC METAMATERIALS
Directory of Open Access Journals (Sweden)
Alexander V. Chebykin
2014-11-01
Full Text Available The paper deals with theoretical demonstration of Purcell effect in extremely anisotropic metamaterials with elliptical isofrequency surface. This effect is free from association with divergence in density of states unlike the case of hyperbolic metamaterials. It is shown that a large Purcell factor can be observed without excitation of modes with large wave vectors in one direction, and the component of the wave vector normal to the layers is less than k0. For these materials the possibility is given for increasing of the power radiated in the medium, as well as the power radiated from material into free space across the medium border situated transversely to the layers. We have investigated isofrequency contours and the dependence of Purcell factor from the frequency for infinite layered metamaterial structure. In the visible light range strong spatial dispersion gives no possibility to obtain enhancement of spontaneous emission in metamaterial with unit cell which consists of two layers. This effect can be achieved in periodic metal-dielectric layered nanostructures with a unit cell containing two different metallic layers and two dielectric ones. Analysis of the dependences for Purcell factor from the frequency shows that the spontaneous emission is enhanced by a factor of ten or more only for dipole orientation along metamaterial layers, but in the case of the transverse orientation radiation can be enhanced only 2-3 times at most. The results can be used to create a new type of metamaterials with elliptical isofrequency contours, providing a more efficient light emission in the far field.
Selection Theory of Dendritic Growth with Anisotropic Diffusion
Directory of Open Access Journals (Sweden)
Martin von Kurnatowski
2015-01-01
Full Text Available Dendritic patterns frequently arise when a crystal grows into its own undercooled melt. Latent heat released at the two-phase boundary is removed by some transport mechanism, and often the problem can be described by a simple diffusion model. Its analytic solution is based on a perturbation expansion about the case without capillary effects. The length scale of the pattern is determined by anisotropic surface tension, which provides the mechanism for stabilizing the dendrite. In the case of liquid crystals, diffusion can be anisotropic too. Growth is faster in the direction of less efficient heat transport (inverted growth. Any physical solution should include this feature. A simple spatial rescaling is used to reduce the bulk equation in 2D to the case of isotropic diffusion. Subsequently, an eigenvalue problem for the growth mode results from the interface conditions. The eigenvalue is calculated numerically and the selection problem of dendritic growth with anisotropic diffusion is solved. The length scale is predicted and a quantitative description of the inverted growth phenomenon is given. It is found that anisotropic diffusion cannot take the stabilizing role of anisotropic surface tension.
Anisotropic diffusion in mesh-free numerical magnetohydrodynamics
Hopkins, Philip F.
2017-04-01
We extend recently developed mesh-free Lagrangian methods for numerical magnetohydrodynamics (MHD) to arbitrary anisotropic diffusion equations, including: passive scalar diffusion, Spitzer-Braginskii conduction and viscosity, cosmic ray diffusion/streaming, anisotropic radiation transport, non-ideal MHD (Ohmic resistivity, ambipolar diffusion, the Hall effect) and turbulent 'eddy diffusion'. We study these as implemented in the code GIZMO for both new meshless finite-volume Godunov schemes (MFM/MFV). We show that the MFM/MFV methods are accurate and stable even with noisy fields and irregular particle arrangements, and recover the correct behaviour even in arbitrarily anisotropic cases. They are competitive with state-of-the-art AMR/moving-mesh methods, and can correctly treat anisotropic diffusion-driven instabilities (e.g. the MTI and HBI, Hall MRI). We also develop a new scheme for stabilizing anisotropic tensor-valued fluxes with high-order gradient estimators and non-linear flux limiters, which is trivially generalized to AMR/moving-mesh codes. We also present applications of some of these improvements for SPH, in the form of a new integral-Godunov SPH formulation that adopts a moving-least squares gradient estimator and introduces a flux-limited Riemann problem between particles.
Weibel Instability Driven by Spatially Anisotropic Density Structures
Tomita, Sara; Ohira, Yutaka
2016-07-01
Observations of afterglows of gamma-ray bursts (GRBs) suggest that post-shock magnetic fields are strongly amplified to about 100 times the shock-compressed value. The Weibel instability appears to play an important role in generating the magnetic field. However, recent simulations of collisionless shocks in homogeneous plasmas show that the magnetic field generated by the Weibel instability rapidly decays. There must be some density fluctuations in interstellar and circumstellar media. The density fluctuations are anisotropically compressed in the downstream region of relativistic shocks. In this paper, we study the Weibel instability in electron-positron plasmas with spatially anisotropic density distributions by means of two-dimensional particle-in-cell simulations. We find that large magnetic fields are maintained for a longer time by the Weibel instability driven by spatially anisotropic density structure. Particles anisotropically escape from the high density region, so that a temperature anisotropy is generated and the Weibel instability becomes unstable. Our simulation results suggest that the Weibel instability driven by an anisotropic density structure can generate sufficiently large magnetic fields and they can cover sufficiently large regions to explain the afterglow emission of GRBs.
2D seismic reflection tomography in strongly anisotropic media
Huang, Guangnan; Zhou, Bing; Li, Hongxi; Zhang, Hua; Li, Zelin
2014-12-01
Seismic traveltime tomography is an effective method to reconstruct underground anisotropic parameters. Currently, most anisotropic tomographic methods were developed under the assumption of weak anisotropy. The tomographic method proposed here can be implemented for imaging subsurface targets in strongly anisotropic media with a known tilted symmetry axis, since the adopted ray tracing method is suitable for anisotropic media with arbitrary degree. There are three kinds of reflection waves (qP, qSV and qSH waves) that were separately used to invert the blocky abnormal body model. The reflection traveltime tomographiy is developed here because a surface observation system is the most economical and practical way compared with crosswell and VSP. The numerical examples show that the traveltimes of qP reflection wave have inverted parameters {{c}11},{{c}13},{{c}33} \\text{and} {{c}44} successfully. Traveltimes of qSV reflection wave have inverted parameters {{c}11},{{c}33} \\text{and} {{c}44} successfully, with the exception of the {{c}13}, since it is less sensitive than other parameters. Traveltimes of qSH reflection wave also have inverted parameters {{c}44} \\text{and} {{c}66} successfully. In addition, we find that the velocity sensitivity functions (derivatives of phase velocity with respect to elastic moduli parameters) and raypath illuminating angles have a great influence on the qualities of tomograms according to the inversion of theoretical models. Finally, the numerical examples confirm that the reflection traveltime tomography can be applied to invert strongly anisotropic models.
Multiple anisotropic collisions for advection-diffusion Lattice Boltzmann schemes
Ginzburg, Irina
2013-01-01
This paper develops a symmetrized framework for the analysis of the anisotropic advection-diffusion Lattice Boltzmann schemes. Two main approaches build the anisotropic diffusion coefficients either from the anisotropic anti-symmetric collision matrix or from the anisotropic symmetric equilibrium distribution. We combine and extend existing approaches for all commonly used velocity sets, prescribe most general equilibrium and build the diffusion and numerical-diffusion forms, then derive and compare solvability conditions, examine available anisotropy and stable velocity magnitudes in the presence of advection. Besides the deterioration of accuracy, the numerical diffusion dictates the stable velocity range. Three techniques are proposed for its elimination: (i) velocity-dependent relaxation entries; (ii) their combination with the coordinate-link equilibrium correction; and (iii) equilibrium correction for all links. Two first techniques are also available for the minimal (coordinate) velocity sets. Even then, the two-relaxation-times model with the isotropic rates often gains in effective stability and accuracy. The key point is that the symmetric collision mode does not modify the modeled diffusion tensor but it controls the effective accuracy and stability, via eigenvalue combinations of the opposite parity eigenmodes. We propose to reduce the eigenvalue spectrum by properly combining different anisotropic collision elements. The stability role of the symmetric, multiple-relaxation-times component, is further investigated with the exact von Neumann stability analysis developed in diffusion-dominant limit.
Nonconforming rotated Q1 element on non-tensor product anisotropic meshes
Institute of Scientific and Technical Information of China (English)
MAO; Shipeng; SHI; Zhongci
2006-01-01
In this paper, we consider the nonconforming rotated Q1 element for the second order elliptic problem on the non-tensor product anisotropic meshes, i.e. the anisotropic affine quadrilateral meshes. Though the interpolation error is divergent on the anisotropic meshes,we overcome this difficulty by constructing another proper operator. Then we give the optimal approximation error and the consistency error estimates under the anisotropic affine quadrilateral meshes. The results of this paper provide some hints to derive the anisotropic error of some finite elements whose interpolations do not satisfy the anisotropic interpolation properties. Lastly, a numerical test is carried out, which coincides with our theoretical analysis.
A role for ADAM12 in breast tumor progression and stromal cell apoptosis
DEFF Research Database (Denmark)
Kveiborg, Marie; Frohlich, Camilla; Albrechtsen, Reidar;
2005-01-01
of stromal fibroblasts in tumor initiation and progression has been elucidated. Here, we show that stromal cell apoptosis occurs in human breast carcinoma but is only rarely seen in nonmalignant breast lesions. Furthermore, we show that ADAM12, a disintegrin and metalloprotease up-regulated in human breast...... cancer, accelerates tumor progression in a mouse breast cancer model. ADAM12 does not influence tumor cell proliferation but rather confers both decreased tumor cell apoptosis and increased stromal cell apoptosis. This dual role of ADAM12 in governing cell survival is underscored by the finding that ADAM......12 increases the apoptotic sensitivity of nonneoplastic cells in vitro while rendering tumor cells more resistant to apoptosis. Together, these results show that the ability of ADAM12 to influence apoptosis may contribute to tumor progression....
Helicobacter pylori vacuolating toxin A and apoptosis
Directory of Open Access Journals (Sweden)
Rassow Joachim
2011-11-01
Full Text Available Abstract VacA, the vacuolating cytotoxin A of Helicobacter pylori, induces apoptosis in epithelial cells of the gastic mucosa and in leukocytes. VacA is released by the bacteria as a protein of 88 kDa. At the outer surface of host cells, it binds to the sphingomyelin of lipid rafts. At least partially, binding to the cells is facilitated by different receptor proteins. VacA is internalized by a clathrin-independent mechanism and initially accumulates in GPI-anchored proteins-enriched early endosomal compartments. Together with early endosomes, VacA is distributed inside the cells. Most of the VacA is eventually contained in the membranes of vacuoles. VacA assembles in hexameric oligomers forming an anion channel of low conductivity with a preference for chloride ions. In parallel, a significant fraction of VacA can be transferred from endosomes to mitochondria in a process involving direct endosome-mitochondria juxtaposition. Inside the mitochondria, VacA accumulates in the mitochondrial inner membrane, probably forming similar chloride channels as observed in the vacuoles. Import into mitochondria is mediated by the hydrophobic N-terminus of VacA. Apoptosis is triggered by loss of the mitochondrial membrane potential, recruitment of Bax and Bak, and release of cytochrome c.
Discrete element modeling of inherently anisotropic granular assemblies with polygonal particles
Institute of Scientific and Technical Information of China (English)
Ehsan Seyedi Hosseininia
2012-01-01
In the present article,we study the effect of inherent anisotropy,i.e.,initial bedding angle of particles and associated voids on macroscopic mechanical behavior of granular materials,by numerical simulation of several biaxial compression tests using the discrete element method (DEM).Particle shape is considered to be irregular convex-polygonal.The effect of inherent anisotropy is investigated by following the evolution of mobilized shear strength and volume change during loading.As experimental tests have already shown,numerical simulations also indicate that initial anisotropic condition has a great influence on the strength and deformational behavior of granular assemblies.Comparison of simulations with tests using oval particles,shows that angularity influences both the mobilized shear strength and the volume change regime,which originates from the interlocking resistance between particles.
Well behaved anisotropic compact star models in general relativity
Jasim, M. K.; Maurya, S. K.; Gupta, Y. K.; Dayanandan, B.
2016-11-01
Anisotropic compact star models have been constructed by assuming a particular form of a metric function e^{λ}. We solved the Einstein field equations for determining the metric function e^{ν}. For this purpose we have assumed a physically valid expression of radial pressure (pr). The obtained anisotropic compact star model is representing the realistic compact objects such as PSR 1937 +21. We have done an extensive study about physical parameters for anisotropic models and found that these parameters are well behaved throughout inside the star. Along with these we have also determined the equation of state for compact star which gives the radial pressure is purely the function of density i.e. pr=f(ρ).
Anisotropic Electron Tail Generation during Tearing Mode Magnetic Reconnection
DuBois, Ami M.; Almagri, Abdulgader F.; Anderson, Jay K.; Den Hartog, Daniel J.; Lee, John David; Sarff, John S.
2017-02-01
The first experimental evidence of anisotropic electron energization during magnetic reconnection that favors a direction perpendicular to the guide magnetic field in a toroidal, magnetically confined plasma is reported in this Letter. Magnetic reconnection plays an important role in particle heating, energization, and transport in space and laboratory plasmas. In toroidal devices like the Madison Symmetric Torus, discrete magnetic reconnection events release large amounts of energy from the equilibrium magnetic field. Fast x-ray measurements imply a non-Maxwellian, anisotropic energetic electron tail is formed at the time of reconnection. The tail is well described by a power-law energy dependence. The expected bremsstrahlung from an electron distribution with an anisotropic energetic tail (v⊥>v∥ ) spatially localized in the core region is consistent with x-ray emission measurements. A turbulent process related to tearing fluctuations is the most likely cause for the energetic electron tail formation.
Nonlinear analysis of traffic jams in an anisotropic continuum model
Institute of Scientific and Technical Information of China (English)
Arvind Kumar Gupta; Sapna Sharma
2010-01-01
This paper presents our study of the nonlinear stability of a new anisotropic continuum traffic flow model in which the dimensionless parameter or anisotropic factor controls the non-isotropic character and diffusive influence. In order to establish traffic flow stability criterion or to know the critical parameters that lead, on one hand, to a stable response to perturbations or disturbances or, on the other hand, to an unstable response and therefore to a possible congestion, a nonlinear stability criterion is derived by using a wavefront expansion technique. The stability criterion is illustrated by numerical results using the finite difference method for two different values of anisotropic parameter. It is also been observed that the newly derived stability results are consistent with previously reported results obtained using approximate linearisation methods. Moreover, the stability criterion derived in this paper can provide more refined information from the perspective of the capability to reproduce nonlinear traffic flow behaviors observed in real traffic than previously established methodologies.
Generation of Curvature Perturbations with Extra Anisotropic Stress
Kojima, Kazuhiko; Mathews, Grant J
2009-01-01
We study the evolution of curvature perturbations and the cosmic microwave background (CMB) power spectrum in the presence of an hypothesized extra anisotropic stress in the early universe. Such extra anisotropic stress terms might arise, for example, from the presence of the dark radiation term in brane-world cosmology. For the first time we evolve the scalar modes of such perturbations before and after neutrino decoupling and analyze their effects on the CMB spectrum. A novel result of this work is that the cancellation of the neutrino and extra anisotropic stress could lead to a spectrum of residual curvature perturbations which by themselves could reproduce the observed CMB power spectrum. This possibility may be testable as it would generate non-Gaussian fluctuations which could be constrained by future observations of density fluctuations.
Geodesic acoustic mode in anisotropic plasma with heat flux
Energy Technology Data Exchange (ETDEWEB)
Ren, Haijun, E-mail: hjren@ustc.edu.cn [CAS Key Laboratory of Geospace Environment and Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)
2015-10-15
Geodesic acoustic mode (GAM) in an anisotropic tokamak plasma is investigated in fluid approximation. The collisionless anisotropic plasma is described within the 16-momentum magnetohydrodynamic (MHD) fluid closure model, which takes into account not only the pressure anisotropy but also the anisotropic heat flux. It is shown that the GAM frequency agrees better with the kinetic result than the standard Chew-Goldberger-Low (CGL) MHD model. When zeroing the anisotropy, the 16-momentum result is identical with the kinetic one to the order of 1/q{sup 2}, while the CGL result agrees with the kinetic result only on the leading order. The discrepancies between the results of the CGL fluid model and the kinetic theory are well removed by considering the heat flux effect in the fluid approximation.
3-D waveform tomography sensitivity kernels for anisotropic media
Djebbi, R.
2014-01-01
The complications in anisotropic multi-parameter inversion lie in the trade-off between the different anisotropy parameters. We compute the tomographic waveform sensitivity kernels for a VTI acoustic medium perturbation as a tool to investigate this ambiguity between the different parameters. We use dynamic ray tracing to efficiently handle the expensive computational cost for 3-D anisotropic models. Ray tracing provides also the ray direction information necessary for conditioning the sensitivity kernels to handle anisotropy. The NMO velocity and η parameter kernels showed a maximum sensitivity for diving waves which results in a relevant choice of those parameters in wave equation tomography. The δ parameter kernel showed zero sensitivity; therefore it can serve as a secondary parameter to fit the amplitude in the acoustic anisotropic inversion. Considering the limited penetration depth of diving waves, migration velocity analysis based kernels are introduced to fix the depth ambiguity with reflections and compute sensitivity maps in the deeper parts of the model.
Strongly interacting particles on an anisotropic kagome lattice
Energy Technology Data Exchange (ETDEWEB)
Hotta, Chisa; Pollmann, Frank, E-mail: chisa@cc.kyoto-su.ac.j [Kyoto Sangyo University, Department of Physics, Faculty of Science, Kyoto 603-8555, Japan Department of Physics, University of California, Berkeley, CA94720 (United States)
2009-01-01
We study a model of strongly interacting spinless fermions and hard-core bosons on an anisotropic kagome lattice near 2/3-filling. Our main focus lies on the strongly anisotropic case in which the nearest-neighbor repulsions V and V' are large compared to the hopping amplitudes |t| and |t'|. When t = t' = 0, the system has a charge ordered insulating ground state where the charges align in striped configurations. Doping one electron or hole into the ground state yields an anisotropic metal at V' > V, where the particle fractionalizes along the V'-bonds while propagates along the V-bonds in a one-body like manner. The sixth order ring exchange processes around the hexagonal unit of the lattice play a crucial role in forming a bound state of fractional charges.
Strongly interacting particles on an anisotropic kagome lattice
Hotta, Chisa; Pollmann, Frank
2009-01-01
We study a model of strongly interacting spinless fermions and hard-core bosons on an anisotropic kagome lattice near 2/3-filling. Our main focus lies on the strongly anisotropic case in which the nearest-neighbor repulsions V and V' are large compared to the hopping amplitudes |t| and |t'|. When t = t' = 0, the system has a charge ordered insulating ground state where the charges align in striped configurations. Doping one electron or hole into the ground state yields an anisotropic metal at V' > V, where the particle fractionalizes along the V'-bonds while propagates along the V-bonds in a one-body like manner. The sixth order ring exchange processes around the hexagonal unit of the lattice play a crucial role in forming a bound state of fractional charges.
Reduction of noise in diffusion tensor images using anisotropic smoothing.
Ding, Zhaohua; Gore, John C; Anderson, Adam W
2005-02-01
To improve the accuracy of tissue structural and architectural characterization with diffusion tensor imaging, a novel smoothing technique is developed for reducing noise in diffusion tensor images. The technique extends the traditional anisotropic diffusion filtering method by allowing isotropic smoothing within homogeneous regions and anisotropic smoothing along structure boundaries. This is particularly useful for smoothing diffusion tensor images in which direction information contained in the tensor needs to be restored following noise corruption and preserved around tissue boundaries. The effectiveness of this technique is quantitatively studied with experiments on simulated and human in vivo diffusion tensor data. Illustrative results demonstrate that the anisotropic smoothing technique developed can significantly reduce the impact of noise on the direction as well as anisotropy measures of the diffusion tensor images.
Vacuum self similar anisotropic cosmologies in $F(R)-$gravity
Apostolopoulos, Pantelis S
2016-01-01
The implications from the existence of a proper Homothetic Vector Field (HVF) on the dynamics of vacuum anisotropic models in $F(R)$ gravitational theory are studied. The fact that \\emph{every} Spatially Homogeneous vacuum model is equivalent, formally, with a \\textquotedblleft flux\\textquotedblright -free anisotropic fluid model in standard gravity and the induced power-law form of the functional $F(R)$ due to self-similarity enable us to close the system of equations. We found some new exact anisotropic solutions that arise as fixed points in the associated dynamical system. The non-existence of Kasner-like (Bianchi type I) solutions in proper $F(R)-$gravity (i.e. $R\
Anisotropic Smoothing Improves DT-MRI-Based Muscle Fiber Tractography.
Directory of Open Access Journals (Sweden)
Amanda K W Buck
Full Text Available To assess the effect of anisotropic smoothing on fiber tracking measures, including pennation angle, fiber tract length, and fiber tract number in the medial gastrocnemius (MG muscle in healthy subjects using diffusion-weighted magnetic resonance imaging (DW-MRI.3T DW-MRI data were used for muscle fiber tractography in the MG of healthy subjects. Anisotropic smoothing was applied at three levels (5%, 10%, 15%, and pennation angle, tract length, fiber tract number, fractional anisotropy, and principal eigenvector orientation were quantified for each smoothing level.Fiber tract length increased with pre-fiber tracking smoothing, and local heterogeneities in fiber direction were reduced. However, pennation angle was not affected by smoothing.Modest anisotropic smoothing (10% improved fiber-tracking results, while preserving structural features.
Anisotropic models are unitary: A rejuvenation of standard quantum cosmology
Pal, Sridip
2016-01-01
The present work proves that the folk-lore of the pathology of non-conservation of probability in quantum anisotropic models is wrong. It is shown in full generality that all operator ordering can lead to a Hamiltonian with a self-adjoint extension as long as it is constructed to be a symmetric operator, thereby making the problem of non-unitarity in context of anisotropic homogeneous model a ghost. Moreover, it is indicated that the self-adjoint extension is not unique and this non-uniqueness is suspected not to be a feature of Anisotropic model only, in the sense that there exists operator orderings such that Hamiltonian for an isotropic homogeneous cosmological model does not have unique self-adjoint extension, albeit for isotropic model, there is a special unique extension associated with quadratic form of Hamiltonian i.e {\\it Friedrichs extension}. Details of calculations are carried out for a Bianchi III model.
Scattering of electromagnetic light waves from a deterministic anisotropic medium
Li, Jia; Chang, Liping; Wu, Pinghui
2015-11-01
Based on the weak scattering theory of electromagnetic waves, analytical expressions are derived for the spectral densities and degrees of polarization of an electromagnetic plane wave scattered from a deterministic anisotropic medium. It is shown that the normalized spectral densities of scattered field is highly dependent of changes of the scattering angle and degrees of polarization of incident plane waves. The degrees of polarization of scattered field are also subjective to variations of these parameters. In addition, the anisotropic effective radii of the dielectric susceptibility can lead essential influences on both spectral densities and degrees of polarization of scattered field. They are highly dependent of the effective radii of the medium. The obtained results may be applicable to determine anisotropic parameters of medium by quantitatively measuring statistics of a far-zone scattered field.
The Derived Equivalent Circuit Model for Magnetized Anisotropic Graphene
Cao, Ying S; Ruehli, Albert E
2015-01-01
Due to the static magnetic field, the conductivity for graphene becomes a dispersive and anisotropic tensor, which complicates most modeling methodologies. In this paper, a novel equivalent circuit model is proposed for graphene with the magnetostatic bias based on the electric field integral equation (EFIE). To characterize the anisotropic property of the biased graphene, the resistive part of the unit circuit is replaced by a resistor in series with current control voltage sources (CCVSs). The CCVSs account for the off-diagonal parts of the surface conductivity tensor for the magnetized graphene. Furthermore, the definitions of the absorption cross section and the scattering cross section are revisited to make them feasible for derived circuit analysis. This proposed method is benchmarked with several numerical examples. This paper also provides a new equivalent circuit model to deal with dispersive and anisotropic materials.
Modeling anisotropic Maxwell-Jüttner distributions: derivation and properties
Livadiotis, George
2016-12-01
In this paper we develop a model for the anisotropic Maxwell-Jüttner distribution and examine its properties. First, we provide the characteristic conditions that the modeling of consistent and well-defined anisotropic Maxwell-Jüttner distributions needs to fulfill. Then, we examine several models, showing their possible advantages and/or failures in accordance to these conditions. We derive a consistent model, and examine its properties and its connection with thermodynamics. We show that the temperature equals the average of the directional temperature-like components, as it holds for the classical, anisotropic Maxwell distribution. We also derive the internal energy and Boltzmann-Gibbs entropy, where we show that both are maximized for zero anisotropy, that is, the isotropic Maxwell-Jüttner distribution.
Anisotropic viscoelastic models in large deformation for architectured membranes
Rebouah, Marie; Chagnon, Gregory; Heuillet, Patrick
2016-08-01
Due to the industrial elaboration process, membranes can have an in-plane anisotropic mechanical behaviour. In this paper, anisotropic membranes elaborated with two different materials were developed either by calendering or by inducing a force in one direction during the process. Experimental tests are developed to measure the differences of mechanical behaviour for both materials in different in-plane properties: stiffness, viscoelasticity and stress-softening. A uniaxial formulation is developed, and a homogenisation by means of a sphere unit approach is used to propose a three-dimensional formulation to represent the materials behaviour. An evolution of the mechanical parameters, depending on the direction, is imposed to reproduce the anisotropic behaviour of the materials. Comparison with experimental data highlights very promising results.
Self-force on dislocation segments in anisotropic crystals
Energy Technology Data Exchange (ETDEWEB)
Fitzgerald, S P [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Aubry, S, E-mail: steve.fitzgerald@ccfe.ac.u [Department of Mechanical Engineering, Stanford University, Stanford, CA (United States)
2010-07-28
A dislocation segment in a crystal experiences a 'self-force', by virtue of the orientation dependence of its elastic energy. If the crystal is elastically isotropic, this force is manifested as a couple acting to rotate the segment toward the lower energy of the pure screw orientation (i.e. acting to align the dislocation line with its Burgers vector). If the crystal is anisotropic, there are additional contributions to the couple, arising from the more complex energy landscape of the lattice itself. These effects can strongly influence the dynamic evolution of dislocation networks, and via their governing role in dislocation multiplication phenomena, control plastic flow in metals. In this paper we develop a model for dislocation self-forces in a general anisotropic crystal, and briefly consider the technologically important example of {alpha}-iron, which becomes increasingly anisotropic as the temperature approaches that of the {alpha}-{gamma} phase transition at 912 {sup 0}C.
Debonding Analyses in Anisotropic Materials with Strain-Gradient Effects
DEFF Research Database (Denmark)
Legarth, Brian Nyvang
2012-01-01
A unit cell approach is adopted to numerically analyze the effect of plastic anisotropy on damage evolution in a microreinforced composite. The matrix material exhibit size effects and a visco-plastic anisotropic strain gradient plasticity model accounting for such size effects is adopted....... A conventional cohesive law is extended such that both the average as well as the jump in plastic strain across the fiber-matrix interface are accounted for. Results are shown for both conventional isotropic and anisotropic materials as well as for higher order isotropic and anisotropic materials...... with and without debonding. Generally, the strain gradient enhanced material exhibits higher load carry capacity compared to the corresponding conventional material. A sudden stress drop occurs in the macroscopic stress-strain response curve due to fiber-matrix debonding and the results show that a change in yield...
Cosmological MHD simulations of cluster formation with anisotropic thermal conduction
Ruszkowski, M; Bruggen, M; Parrish, I; Oh, S Peng
2010-01-01
(abridged) The ICM has been suggested to be buoyantly unstable in the presence of magnetic field and anisotropic thermal conduction. We perform first cosmological simulations of galaxy cluster formation that simultaneously include magnetic fields, radiative cooling and anisotropic thermal conduction. In isolated and idealized cluster models, the magnetothermal instability (MTI) tends to reorient the magnetic fields radially. Using cosmological simulations of the Santa Barbara cluster we detect radial bias in the velocity and magnetic fields. Such radial bias is consistent with either the inhomogeneous radial gas flows due to substructures or residual MTI-driven field rearangements that are expected even in the presence of turbulence. Although disentangling the two scenarios is challenging, we do not detect excess bias in the runs that include anisotropic thermal conduction. The anisotropy effect is potentially detectable via radio polarization measurements with LOFAR and SKA and future X-ray spectroscopic stu...
The Shear Viscosity in an Anisotropic Unitary Fermi Gas
Samanta, Rickmoy; Trivedi, Sandip P
2016-01-01
We consider a system consisting of a strongly interacting, ultracold unitary Fermi gas under harmonic confinement. Our analysis suggests the possibility of experimentally studying, in this system, an anisotropic shear viscosity tensor driven by the anisotropy in the trapping potential. In particular, we suggest that this experimental setup could mimic some features of anisotropic geometries that have recently been studied for strongly coupled field theories which have a gravitational dual. Results using the AdS/CFT correspondence in these theories show that in systems with a background linear potential, certain viscosity components can be made much smaller than the entropy density, parametrically violating the KSS bound. This intuition, along with results from a Boltzmann analysis that we perform, suggests that a violation of the KSS bound can perhaps occur in the unitary Fermi gas system when it is subjected to a suitable anisotropic trapping potential. We give a concrete proposal for an experimental setup w...
Duan, K.; Kwok, C. Y.
2016-04-01
The aim of this study is to better understand the mechanisms controlling the initiation, propagation, and ultimate pattern of borehole breakouts in shale formation when drilled parallel with and perpendicular to beddings. A two-dimensional discrete element model is constructed to explicitly represent the microstructure of inherently anisotropic rocks by inserting a series of individual smooth joints into an assembly of bonded rigid discs. Both isotropic and anisotropic hollow square-shaped samples are generated to represent the wellbores drilled perpendicular to and parallel with beddings at reduced scale. The isotropic model is validated by comparing the stress distribution around borehole wall and along X axis direction with analytical solutions. Effects of different factors including the particle size distribution, borehole diameter, far-field stress anisotropy, and rock anisotropy are systematically evaluated on the stress distribution and borehole breakout propagation. Simulation results reveal that wider particle size distribution results in the local stress perturbations which cause localization of cracks. Reduction of borehole diameter significantly alters the crack failure from tensile to shear and raises the critical pressure. Rock anisotropy plays an important role on the stress state around wellbore which lead to the formation of preferred cracks under hydrostatic stress. Far-field stress anisotropy plays a dominant role in the shape of borehole breakout when drilled perpendicular to beddings while a secondary role when drilled parallel with beddings. Results from this study can provide fundamental insights on the underlying particle-scale mechanisms for previous findings in laboratory and field on borehole stability in anisotropic rock.
Anisotropic metamaterials for microwave antennas and infrared nanostructured thin films
Jian, Zhihao
Wave-matter interactions have long been investigated to discover unknown physical phenomena and exploited to achieve improved device performance throughout the electromagnetic spectrum ranging from quasi-static limit to microwave frequencies, and even at infrared and optical wavelengths. As a nascent but fast growing field, metamaterial technology, which relies on clusters of artificially engineered subwavelength structures, has been demonstrated to provide a wide variety of exotic electromagnetic properties unattainable in natural materials. This dissertation presents the research on novel anisotropic metamaterials for tailoring microwave radiation and infrared scattering of nanostructured thin films. First, a new inversion algorithm is proposed for retrieving the anisotropic effective medium parameters of a slab of metamaterial. Secondly, low-loss anisotropic metamaterial lenses and coatings are introduced for improving the gain and/or bandwidth for a variety of antennas. In particular, a quad-beam high-gain lens for a quarter-wave monopole, a low-profile grounded leaky metamaterial coating for slot antenna, and an ultra-thin anisotropic metamaterial bandwidth-enhancing coating for a quarter-wave monopole are experimentally demonstrated. In the infrared regime, novel nanostructured metamaterial free-standing thin-films, which are inherently anisotropic, are introduced for achieving exotic index properties and further for practical photonic devices. In particular, a low-loss near-infrared fishnet zero-index metamaterial, a dispersionengineered optically-thin, low-loss broadband metamaterial filter with a suppressed group delay fluctuation in the mid-infrared, and a conformal dual-band near-perfectly absorbing coating in the mid-infrared are experimentally demonstrated. These explorations show the great promise anisotropic metamaterials hold for the flexible manipulation of electromagnetic waves and their broad applicability in a wide spectrum range.
Cardiomyocytic apoptosis and heart failure
Institute of Scientific and Technical Information of China (English)
Quanzhou Feng
2008-01-01
Heart failure is a major disease seriously threatening human health.Once left ventricular dysfunction develops,cardiac function usually deteriorates and progresses to congestive heart failure in several months or years even if no factors which accelerate the deterioration repeatedly exist.Mechanism through which cardiac function continually deteriorates is still unclear.Cardiomyocytic apoptosis can occur in acute stage of ischemic heart diseases and the compensated stage of cardiac dysfunction.In this review,we summarize recent advances in understanding the role of cardiomyocytic apoptosis in heart failure.
Debonding of perticles in anisotropic materials
DEFF Research Database (Denmark)
Legarth, Brian Nyvang
2003-01-01
is calculated. For increased triaxiality the onset of matrix-particle debonding occurs at a significantly reduced overall strain of the cell. The point of initial debonding is nearly unaffected by variations of the shape of the inclusions, but complete debonding occurs earlier if the inclusions are elongated...... if the material was plastically isotropic. It is found for mixed geometrical and plastic anisotropy, that plastic anisotropy promotes debonding initiation, whereas the occurrence of complete matrix-particle debonding is quite sensitive to the type of geometrical anisotropy....
The thermoelectric magnetic field of isotropic inclusions in anisotropic metals
Faidi, W. I.; Nayfeh, A. H.
2006-02-01
In this paper we model the thermoelectric magnetic field around isotropic inclusions in anisotropic media. It is demonstrated that while the presence of the inclusion will be the dominant source of the thermoelectric signal, the anisotropy of the host material will affect the signal. Although such a phenomenon will occur for all shapes of inclusions, for simplicity we shall demonstrate our theoretical and numerical modeling on the more mathematically tractable case of a cylindrical inclusion aligned along an axis of symmetry of an anisotropic metal medium.
Notes on shear viscosity bound violation in anisotropic models
Ge, Xian-Hui
2015-01-01
The shear viscosity bound violation in Einstein gravity for anisotropic black branes is discussed, with the aim of constraining the deviation of the shear viscosity-entropy density ratio from the shear viscosity bound using causality and thermodynamics analysis. The results show that no stringent constraints can be imposed. The diffusion bound in anisotropic phases is also studied. Ultimately, it is concluded that shear viscosity violation always occurs in cases where the equation of motion of the metric fluctuations cannot be written in a form identical to that of the minimally coupled massless scalar fields.
Anisotropic magnetoresistance dominant in a three terminal Hanle measurement
Malec, Christopher; Miller, Michael M.; Johnson, Mark
2016-02-01
Experiments are performed on mesoscopic nonlocal lateral spin valves with aluminum channels and Permalloy electrodes. Four-terminal magnetoresistance and Hanle measurements characterize the spin accumulation with results that compare well with published work. Three-terminal Hanle measurements of the Permalloy/aluminum (Py/Al) interfaces show bell-shaped curves that can be fit to Lorentzians. These curves are three orders of magnitude larger than the spin accumulation. Using anisotropic magnetoresistance measurements of individual Permalloy electrodes, we demonstrate that the three-terminal measurements are dominated by anisotropic magnetoresistance effects unrelated to spin accumulation.
Interfacial contribution to thickness dependent in-plane anisotropic magnetoresistance
Directory of Open Access Journals (Sweden)
M. Tokaç
2015-12-01
Full Text Available We have studied in-plane anisotropic magnetoresistance (AMR in cobalt films with overlayers having designed electrically interface transparency. With an electrically opaque cobalt/overlayer interface, the AMR ratio is shown to vary in inverse proportion to the cobalt film thickness; an indication that in-plane AMR is a consequence of anisotropic scattering with both volume and interfacial contributions. The interface scattering anisotropy opposes the volume scattering contribution, causing the AMR ratio to diminish as the cobalt film thickness is reduced. An intrinsic interface effect explains the significantly reduced AMR ratio in ultra-thin films.
The design of metamaterial cloaks embedded in anisotropic medium
Institute of Scientific and Technical Information of China (English)
Ma Hua; Qu Shao-Bo; Xu Zhuo; Zhang Jie-Qiu; Wang Jia-Fu
2009-01-01
By using coordinate transformation method, this paper obtains an useful equation of designing meta-material cloaks embedded in anisotropic medium. This equation is the generalization of what was introduced early by Pendry et al (2006 Science 312 1780) and can be more widely used. As an example of its applications, this paper deduces the material parameter equation for cylinder cloaks embedded in anisotropic medium, and then offers the numerical simulation. The results show that such a cylinder cloak has perfect cloaking performance and therefore verifies the method proposed in this paper.
MHz gravitational waves from short-term anisotropic inflation
Energy Technology Data Exchange (ETDEWEB)
Ito, Asuka; Soda, Jiro [Department of Physics, Kobe University,Kobe 657-8501 (Japan)
2016-04-18
We reveal the universality of short-term anisotropic inflation. As a demonstration, we study inflation with an exponential type gauge kinetic function which is ubiquitous in models obtained by dimensional reduction from higher dimensional fundamental theory. It turns out that an anisotropic inflation universally takes place in the later stage of conventional inflation. Remarkably, we find that primordial gravitational waves with a peak amplitude around 10{sup −26}∼10{sup −27} are copiously produced in high-frequency bands 10 MHz∼100 MHz. If we could detect such gravitational waves in future, we would be able to probe higher dimensional fundamental theory.
Q-factor enhancement in all-dielectric anisotropic nanoresonators
Liu, Wei; Kivshar, Yuri S
2016-01-01
It is proposed and demonstrated that Q-factor of optical resonators can be significantly enhanced by introducing an extra anisotropic cladding. We study the optical resonances of all-dielectric core-shell nanoresonators and reveal that radially anisotropic claddings can be employed to squeeze more energy into the core area, leading to stronger light confinement and thus significant Q-factor enhancement. We further show that the required homogenous claddings of unusual anisotropy parameters can be realized through all-dielectric multi-layered isotropic structures, which offers realistic extra flexibilities of resonance manipulations for optical resonators.
Electric fields inside and outside an anisotropic dielectric sphere
Institute of Scientific and Technical Information of China (English)
Li Ying-Le; Wang Ming-Jun
2009-01-01
Analytical expressions of electric fields inside and outside an anisotropic dielectric sphere are presented by transforming an anisotropic medium into an isotropic one based on the multi-scale transformation of electromagnetic theory.The theoretical expressions are consistent with those in the literature. The inside electric field, the outside electric field and the angle between their directions are derived in detail. Numerical simulations show that the direction of the outside field influences the magnitude of the inside field, while the dielectric constant tensor greatly affects its direction.
Tunable waveguide bends with graphene-based anisotropic metamaterials
Chen, Zhao-xian
2016-01-15
We design tunable waveguide bends filled with graphene-based anisotropic metamaterials to achieve a nearly perfect bending effect. The anisotropic properties of the metamaterials can be described by the effective medium theory. The nearly perfect bending effect is demonstrated by finite element simulations of various structures with different bending curvatures and shapes. This effect is attributed to zero effective permittivity along the direction of propagation and matched effective impedance at the interfaces between the bending part and the dielectric waveguides. We envisage that the design will be applicable in the far-infrared and terahertz frequency ranges owing to the tunable dielectric responses of graphene.
Thermal Entanglement of Anisotropic XY Chains in a Transverse Field
Institute of Scientific and Technical Information of China (English)
ZHAI Xiao-Yue; TONG Pei-Qing
2007-01-01
By using the concept of concurrence, we numerically investigate the thermal entanglement between any two nearest-neighbour spins in uniform and periodic anisotropic XY chains in a transverse field at finite temperature T. It is found that the entanglement has more than one critical temperatures on some parameter regions for uniform and periodic chains. We also discuss the behaviour of the thermal entanglement at the vicinity of quantum phase transition of periodic anisotropic XY chains and find that all the derivatives (δ)λC have similar behaviour as that of the uniform chain.
AN ANISOTROPIC NONCONFORMING FINITE ELEMENT WITH SOME SUPERCONVERGENCE RESULTS
Institute of Scientific and Technical Information of China (English)
Dong-yang Shi; Shi-peng Mao; Shao-chun Chen
2005-01-01
The main aim of this paper is to study the error estimates of a nonconforming finite element with some superconvergence results under anisotropic meshes. The anisotropic interpolation error and consistency error estimates are obtained by using some novel approaches and techniques, respectively. Furthermore, the superclose and a superconvergence estimate on the central points of elements are also obtained without the regularity assumption and quasi-uniform assumption requirement on the meshes. Finally, a numerical test is carried out, which coincides with our theoretical analysis.
Anisotropic Landau-Lifshitz-Gilbert models of dissipation in qubits
Crowley, Philip J. D.; Green, A. G.
2016-12-01
We derive a microscopic model for dissipative dynamics in a system of mutually interacting qubits coupled to a thermal bath that generalizes the dissipative model of Landau-Lifshitz-Gilbert to the case of anisotropic bath couplings. We show that the dissipation acts to bias the quantum trajectories towards a reduced phase space. This model applies to a system of superconducting flux qubits whose coupling to the environment is necessarily anisotropic. We study the model in the context of the D-Wave computing device and show that the form of environmental coupling in this case produces dynamics that are closely related to several models proposed on phenomenological grounds.
Phase Space of Anisotropic $R^n$ Cosmologies
Leon, Genly
2014-01-01
We construct general anisotropic cosmological scenarios governed by an $f(R)=R^n$ gravitational sector. Focusing then on some specific geometries, and modelling the matter content as a perfect fluid, we perform a phase-space analysis. We analyze the possibility of accelerating expansion at late times, and additionally, we determine conditions for the parameter $n$ for the existence of phantom behavior, contracting solutions as well as of cyclic cosmology. Furthermore, we analyze if the universe evolves towards the future isotropization without relying on a cosmic no-hair theorem. Our results indicate that anisotropic geometries in modified gravitational frameworks present radically different cosmological behaviors compared to the simple isotropic scenarios.
MHz Gravitational Waves from Short-term Anisotropic Inflation
Ito, Asuka
2016-01-01
We reveal the universality of short-term anisotropic inflation. As a demonstration, we study inflation with an exponential type gauge kinetic function which is ubiquitous in models obtained by dimensional reduction from higher dimensional fundamental theory. It turns out that an anisotropic inflation universally takes place in the later stage of conventional inflation. Remarkably, we find that primordial gravitational waves with a peak amplitude around $10^{-26}$ ~ $10^{-27}$ are copiously produced in high-frequency bands 10MHz~100MHz. If we could detect such gravitational waves in future, we would be able to probe higher dimensional fundamental theory.
Laser ceramics with rare-earth-doped anisotropic materials.
Akiyama, Jun; Sato, Yoichi; Taira, Takunori
2010-11-01
The fabrication of laser-grade anisotropic ceramics by a conventional sintering process is not possible owing to optical scattering at randomly oriented grain boundaries. In this Letter, we report the first (to our knowledge) realization of transparent anisotropic ceramics by using a new crystal orientation process based on large magnetic anisotropy induced by 4f electrons. By slip casting in a 1.4 T magnetic field and subsequent heat treatments, we could successfully fabricate laser-grade calcium fluorapatite ceramics with a loss coefficient of 1.5 cm(-1).
Anisotropic magnetotransport in Dirac-Weyl magnetic junctions
Ominato, Yuya; Kobayashi, Koji; Nomura, Kentaro
2017-02-01
We theoretically study the anisotropic magnetotransport in Dirac-Weyl magnetic junctions where a doped ferromagnetic Weyl semimetal is sandwiched between doped Dirac semimetals. We calculate the conductance using the Landauer formula and find that the system exhibits extraordinarily large anisotropic magnetoresistance (AMR). The AMR depends on the ratio of the Fermi energy to the strength of the exchange interaction. The origin of the AMR is the shift of the Fermi surface in the Weyl semimetal, and the mechanism is completely different from the conventional AMR originating from the spin dependent scattering and the spin-orbit interaction.
Nonlinear dynamic analysis of quasi-symmetric anisotropic structures
Noor, Ahmed K.; Peters, Jeanne M.
1987-01-01
An efficient computational method for the nonlinear dynamic analysis of quasi-symmetric anisotropic structures is proposed. The application of mixed models simplifies the analytical development and improves the accuracy of the response predictions, and operator splitting allows the reduction of the analysis model of the quasi-symmetric structure to that of the corresponding symmetric structure. The preconditoned conjugate gradient provides a stable and effective technique for generating the unsymmetric response of the structure as the sum of a symmetrized response plus correction modes. The effectiveness of the strategy is demonstrated with the example of a laminated anisotropic shallow shell of quadrilateral planform subjected to uniform normal loading.
Anisotropic thermoelement in emf and current generation mode
Directory of Open Access Journals (Sweden)
Anatychuk L. I.
2011-06-01
Full Text Available Computer methods for the description of the anisotropic thermoelement (AT properties with regard to all necessary model approximations have been elaborated. Configurations of eddy thermoelectric currents in the anisotropic thermoele-ment caused by current contacts have been found. The pro-perties of the AT with regard to temperature dependences of material properties, contact resistances and current contacts have been determined for concrete cases. Optimal dimensions of current contacts have been found. The optimization of AT construction allowed to increase its efficiency by 15%.
Propagation of linear waves in relativistic anisotropic magnetohydrodynamics.
Gebretsadkan, W B; Kalra, G L
2002-11-01
Gedalin [Phys. Rev. E 47, 4354 (1993)] derived a dispersion relation for linear waves in relativistic anisotropic Magnetohydrodynamics (MHD). This dispersion relation is used to point out the regions where the relativistic anisotropic MHD leads to new results that cannot be obtained using usual collisional relativistic MHD. This is highlighted by plotting a Fresnal ray surface. Conditions for the onset of firehose and mirror instabilities are also indicated. Such a study can be applied to astrophysical features such as pulsar winds, propagation of cosmic rays, etc.
Electric double layer of anisotropic dielectric colloids under electric fields
Han, M.; Wu, H.; Luijten, E.
2016-07-01
Anisotropic colloidal particles constitute an important class of building blocks for self-assembly directed by electrical fields. The aggregation of these building blocks is driven by induced dipole moments, which arise from an interplay between dielectric effects and the electric double layer. For particles that are anisotropic in shape, charge distribution, and dielectric properties, calculation of the electric double layer requires coupling of the ionic dynamics to a Poisson solver. We apply recently proposed methods to solve this problem for experimentally employed colloids in static and time-dependent electric fields. This allows us to predict the effects of field strength and frequency on the colloidal properties.
Surface waves in ﬁbre-reinforced anisotropic elastic media
Indian Academy of Sciences (India)
P R Sengupta; Sisir Nath
2001-08-01
The aim of this paper is to investigate surface waves in anisotropic ﬁbre-reinforced solid elastic media. First, the theory of general surface waves has been derived and applied to study the particular cases of surface waves – Rayleigh, Love and Stoneley types. The wave velocity equations are found to be in agreement with the corresponding classical result when the anisotropic elastic parameters tends to zero. It is important to note that the Rayleigh type of wave velocity in the ﬁbre-reinforced elastic medium increases to a considerable amount in comparison with the Rayleigh wave velocity in isotropic materials.
Anomalous Positive Refraction in an Anisotropic Left-Handed Medium
Institute of Scientific and Technical Information of China (English)
HU Wei; LUO Hai-Lu; CAO Jing-Xiao
2005-01-01
@@ We investigate the refraction phenomena of extraordinary light at a planar interface associated with a uniaxial left-handed medium. It is found that the anomalous positive refraction can occur at the interface from anisotropic right-handed medium to a uniaxially anisotropic left-handed medium. When the optical axis of a uniaxial left-handed medium is not normal or parallel to the interface, the refraction of the Poynting vector for the extraordinary waves can be either positive or negative depending on the incident angles, while the refraction of the wave vector is always negative. The physical essential of the anomalous positive refraction results from the anisotropy of uniaxial crystals.
Tunable waveguide bends with graphene-based anisotropic metamaterials
Chen, Zhao-xian; Chen, Ze-guo; Ming, Yang; Wu, Ying; Lu, Yan-qing
2016-02-01
We design tunable waveguide bends filled with graphene-based anisotropic metamaterials to achieve a nearly perfect bending effect. The anisotropic properties of the metamaterials can be described by the effective medium theory. The nearly perfect bending effect is demonstrated by finite element simulations of various structures with different bending curvatures and shapes. This effect is attributed to zero effective permittivity along the direction of propagation and matched effective impedance at the interfaces between the bending part and the dielectric waveguides. We envisage that the design will be applicable in the far-infrared and terahertz frequency ranges owing to the tunable dielectric responses of graphene.
Stopping power of an electron gas with anisotropic temperature
Khelemelia, O. V.; Kholodov, R. I.
2016-04-01
A general theory of motion of a heavy charged particle in the electron gas with an anisotropic velocity distribution is developed within the quantum-field method. The analytical expressions for the dielectric susceptibility and the stopping power of the electron gas differs in no way from well-known classic formulas in the approximation of large and small velocities. Stopping power of the electron gas with anisotropic temperature in the framework of the quantum-field method is numerically calculated for an arbitrary angle between directions of the motion of the projectile particle and the electron beam. The results of the numerical calculations are compared with the dielectric model approach.
Timoshenko beam element with anisotropic cross-sectional properties
DEFF Research Database (Denmark)
Stäblein, Alexander; Hansen, Morten Hartvig
2016-01-01
Beam models are used for the aeroelastic time and frequency domain analysis of wind turbines due to their computational efficiency. Many current aeroelastic tools for the analysis of wind turbines rely on Timoshenko beam elements with classical crosssectional properties (EA, EI, etc.). Those cross......-sectional properties do not reflect the various couplings arising from the anisotropic behaviour of the blade material. A twonoded, three-dimensional Timoshenko beam element was therefore extended to allow for anisotropic cross-sectional properties. For an uncoupled beam, the resulting shape functions are identical...
Vives, Joaquim; Juanola, Sandra; Cairó, Jordi Joan; Gòdia, Francesc
2003-04-01
Animal cells have been widely used to obtain a wide range of products for human and animal healthcare applications. However, the extreme sensitivity of these cells in respect to changes experienced in their environment is evidenced by the activation of a gene-encoded program known as apoptosis, resulting in their death and destruction. From the bioprocess angle, losses in cell viability bring lower productivities and higher risks of product degradation. Consequently, many research efforts have been devoted to the development of apoptosis protective mechanisms, including the metabolic engineering of apoptosis pathways, that has proven effective in diminishing programmed cell death in a variety of biotechnological relevant cell lines. This review is focused especially in the encouraging initial results obtained with the over-expression of cloned anti-apoptosis genes, from both endogenous and viral origin interfering at mitochondrial and initiator caspases levels.
Induction of apoptosis in purified animal and plant nuclei by Xenopus egg extracts
Institute of Scientific and Technical Information of China (English)
JIANGZHENGFAN; SHANZHU; 等
1999-01-01
We have developed a cell-free system that can trigger the nuclei purified from mouse liver and suspensioncultured carrot cells to undergo apoptosis as defined by the formation of apoptotic bodies and nucleosomal DNA fragments.The effects of different divalent cations and cycloheximide on DNA cleavage in this system were assessed.The fact that nuclei of plant cells can be induced to undergo apoptosis in a cell-free animal system suggests that animals and plants share a common signal transduction pathway triggering in the initiation stage of apoptosis.
Development of Pore Pressure in Cohesionless Soils with Initial Shear Stresses during Cyclic Loading
DEFF Research Database (Denmark)
Ibsen, Lars Bo; Jacobsen, H. Moust
1989-01-01
A number of triaxial tests with the loading harmonically oscillating around an initial and anisotropic stress state have been performed. Hereby the influence of the initial shear stress on the development of pore pressure in a cohesionless sand specimen have been clarified. A simple theory descr...
Institute of Scientific and Technical Information of China (English)
Ding Yi; Chang Cunqing; Xie Lan; Chen Zhimin; Ai Hua
2014-01-01
Background Intense exercise can cause injury and apoptosis,but few studies have reported its effect on the central nervous system (CNS).The initial reason for hippocampus injury is the excitotoxicity of glutamate and calcium overload.Intracellular free Ca2+ ([Ca2+]i) overload may trigger the apoptosis pathway and neuron damage.The aim of this study was to investigate whether intense exercise could cause hippocampus apoptosis and neuron damage and then to determine which pathway was activated by this apoptosis.Methods We used one bout of swimming exhaustion rats as models.Intracellular [Ca2+]i was measured to estimate the calcium overload by Fura-2/AM immediately after exhaustion; glial fibrillary acidic protein (GFAP) and synaptophysin (SYP)immunofluorescence were performed for estimating astrocyte activation and synapse plasticity 24 hours after exhaustion.Apoptosis cells were displayed using dUTP nick end labelling (TUNEL) stain; endoplasmic reticulum (ER) stress-induced apoptosis pathway and mitochondrial apoptosis pathway were synchronously detected by Western blotting.Results An increasing level of intracellular [Ca2+]i (P ＜0.01) was found in the hippocampus immediately after exhaustion.GFAP and SYP immunofluorescence showed that the astrocytes are activated,and the synapse plasticity collapsed significantly 24 hours after exhaustion.TUNEL stain showed that the number of apoptosis cells were notably raised (P ＜0.01); Western blotting of the apoptosis pathway showed increasing levels of caspase-3 cleavage (P ＜0.01),Bax (P ＜0.01),caspase-12 cleavage (P ＜0.01),C/EBP-homologous protein (CHOP) (P ＜0.01),and phospho-Junaminoterminal kinases (p-JNK; P ＜0.01) and decreasing level of Bcl-2 (P ＜0.01).Our results proved that exhaustion can induce hippocampus injury and apoptosis by [Ca2+]i overload,with collapsed synaptic plasticity as the injury pattern and ER stress-induced apoptosis as the activated pathway.Conclusion Intense exercise can cause
Neem oil limonoids induces p53-independent apoptosis and autophagy.
Srivastava, Pragya; Yadav, Neelu; Lella, Ravi; Schneider, Andrea; Jones, Anthony; Marlowe, Timothy; Lovett, Gabrielle; O'Loughlin, Kieran; Minderman, Hans; Gogada, Raghu; Chandra, Dhyan
2012-11-01
Azadirachta indica, commonly known as neem, has a wide range of medicinal properties. Neem extracts and its purified products have been examined for induction of apoptosis in multiple cancer cell types; however, its underlying mechanisms remain undefined. We show that neem oil (i.e., neem), which contains majority of neem limonoids including azadirachtin, induced apoptotic and autophagic cell death. Gene silencing demonstrated that caspase cascade was initiated by the activation of caspase-9, whereas caspase-8 was also activated late during neem-induced apoptosis. Pretreatment of cancer cells with pan caspase inhibitor, z-VAD inhibited activities of both initiator caspases (e.g., caspase-8 and -9) and executioner caspase-3. Neem induced the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, suggesting the involvement of both caspase-dependent and AIF-mediated apoptosis. p21 deficiency caused an increase in caspase activities at lower doses of neem, whereas p53 deficiency did not modulate neem-induced caspase activation. Additionally, neem treatment resulted in the accumulation of LC3-II in cancer cells, suggesting the involvement of autophagy in neem-induced cancer cell death. Low doses of autophagy inhibitors (i.e., 3-methyladenine and LY294002) did not prevent accumulation of neem-induced LC3-II in cancer cells. Silencing of ATG5 or Beclin-1 further enhanced neem-induced cell death. Phosphoinositide 3-kinase (PI3K) or autophagy inhibitors increased neem-induced caspase-3 activation and inhibition of caspases enhanced neem-induced autophagy. Together, for the first time, we demonstrate that neem induces caspase-dependent and AIF-mediated apoptosis, and autophagy in cancer cells.
Anisotropic mechanical properties and Stone-Wales defects in graphene monolayer: A theoretical study
Energy Technology Data Exchange (ETDEWEB)
Fan, B.B. [School of Materials Science and Engineering, Zhengzhou University, Henan 450001 (China); Yang, X.B. [Department of Physics, South China University of Technology, Guangzhou 510640 (China); Zhang, R., E-mail: zhangray@zzu.edu.c [School of Materials Science and Engineering, Zhengzhou University, Henan 450001 (China); Zhengzhou Institute of Aeronautical Industry Management, Henan 450046 (China)
2010-06-14
We investigate the mechanical properties of graphene monolayer via the density functional theoretical (DFT) method. We find that the strain energies are anisotropic for the graphene under large strain. We attribute the anisotropic feature to the anisotropic sp{sup 2} hybridization in the hexagonal lattice. We further identify that the formation energies of Stone-Wales (SW) defects in the graphene monolayer are determined by the defect concentration and also the direction of applied tensile strain, correlating with the anisotropic feature.
A Morphing framework to couple non-local and local anisotropic continua
Azdoud, Yan
2013-05-01
In this article, we develop a method to couple anisotropic local continua with anisotropic non-local continua with central long-range forces. First, we describe anisotropic non-local models based on spherical harmonic descriptions. We then derive compatible classic continuum models. Finally, we apply the morphing method to these anisotropic non-local models and present three-dimensional numerical examples to validate the efficiency of the technique. © 2013 Elsevier Ltd. All rights reserved.
Boyd, O.S.
2006-01-01
We have created a second-order finite-difference solution to the anisotropic elastic wave equation in three dimensions and implemented the solution as an efficient Matlab script. This program allows the user to generate synthetic seismograms for three-dimensional anisotropic earth structure. The code was written for teleseismic wave propagation in the 1-0.1 Hz frequency range but is of general utility and can be used at all scales of space and time. This program was created to help distinguish among various types of lithospheric structure given the uneven distribution of sources and receivers commonly utilized in passive source seismology. Several successful implementations have resulted in a better appreciation for subduction zone structure, the fate of a transform fault with depth, lithospheric delamination, and the effects of wavefield focusing and defocusing on attenuation. Companion scripts are provided which help the user prepare input to the finite-difference solution. Boundary conditions including specification of the initial wavefield, absorption and two types of reflection are available. ?? 2005 Elsevier Ltd. All rights reserved.
Anisotropic Effects on Magnetoelastic Transition in Magnetic Molecular Rings
Institute of Scientific and Technical Information of China (English)
LI Peng-Fei; CHEN Yu-Guang; CHEN Hong
2006-01-01
@@ We numerically study the anisotropic effects on the magnetoelastic transition in an S = 1/2 XXZ model with a finite lattice number. It is found that the order of the magnetoelastic transition is strongly affected by the anisotropy parameter A and there may exist a critical λc dividing the first-order transition and the continuous transition.
Influence of anisotropic piezoelectric actuators on wing aerodynamic forces
Institute of Scientific and Technical Information of China (English)
2008-01-01
Changing the shape of an airfoil to enhance overall aircraft performance has always been a goal of aircraft designers. Using smart material to reshape the wing can improve aerodynamic performance. The influence of anisotropic effects of piezoelectric actuators on the aerodynamic characteristics of a simplified HALE wing model was investigated. Test verification was conducted.
Influence of anisotropic piezoelectric actuators on wing aerodynamic forces
Institute of Scientific and Technical Information of China (English)
GUAN De; LI Min; LI Wei; WANG MingChun
2008-01-01
Changing the shape of an airfoil to enhance overall aircraft performance has always been s goal of aircraft designers.Using smart material to reshape the wing can improve aerodynamic performance.The influence of anisotropic effects of piezo-electric actuators on the aerodynamic characteristics of a simplified HALE wing model was investigated.Test verification was conducted.
A new noise erosion operator for anisotropic diffusion
Institute of Scientific and Technical Information of China (English)
Chao Cai(蔡超); Mingyue Ding(丁名跃); Chengping Zhou(周成平); Tianxu Zhang(张天序)
2004-01-01
A noise erosion operator based on partial differential equation (PDE) is introduced, which has an excellent ability of noise removal and edge preservation for two-dimensional (2D) gradient data. The operator is applied to estimate a new diffusion coefficient. Experimental results demonstrate that anisotropic diffusion based on this new erosion operator can efficiently reduce noise and sharpen object boundaries.
Exact Solutions of the Photon Equation in Anisotropic Spacetimes
Havare, A; Aydogdu, O; Salti, M; Yetkin, T; Havare, Ali; Korunur, Murat; Aydogdu, Oktay; Salti, Mustafa; Yetkin, Taylan
2005-01-01
In this paper we study solution of the photon equation (the Massless Duffin-Kemmer-Petiau equation (mDKP)) in anisotropic expanding the Bianchi-I type spacetime using the Fourier analyze method. The harmonic oscillator behavior of the solutions is found. It is shown that Maxwell equations are equivalent to the photon equation.
Anisotropic plastic deformation by viscous flow in ion tracks
van Dillen, T; Polman, A; Onck, PR; van der Giessen, E
2005-01-01
A model describing the origin of ion beam-induced anisotropic plastic deformation is derived and discussed. It is based on a viscoelastic thermal spike model for viscous flow in single ion tracks derived by Trinkaus and Ryazanov. Deviatoric (shear) stresses, brought about by the rapid thermal expans
Hysteresis behavior of the anisotropic quantum Heisenberg model
Energy Technology Data Exchange (ETDEWEB)
Akıncı, Ümit, E-mail: umit.akinci@deu.edu.tr
2013-10-15
The effect of the anisotropy in the exchange interaction on the hysteresis loops within the anisotropic quantum Heisenberg model has been investigated with the effective field theory for two spin cluster. Particular attention has been devoted on the behavior of the hysteresis loop area, coercive field and remanent magnetization with the anisotropy in the exchange interaction for both ferromagnetic and paramagnetic phases.
Tuning particle geometry of chemically anisotropic dumbbell-shaped colloids
van Ravensteijn, Bas G P; Kegel, Willem K
2017-01-01
Chemically anisotropic dumbbell-shaped colloids are prepared starting from cross-linked polymer seed particles coated with a chlorinated outer layer. These chlorinated seeds are swollen with monomer. Subsequently, a liquid protrusion is formed on the surface of the seed particle by phase separation
Generalized anisotropic strange star models for compact stars
Mauryaa, S K; Dayanandan, Baiju; Jasim, M K; Al-Jamel, Ahmed
2015-01-01
We present new anisotropic generalization of Buchdahl [1] type perfect fluid solution by using the method of earlier work [2]. In similar approach we have constructed the new pressure anisotropy factor {\\Delta} by the help both the metric potential e^{\\lambda} and e^{\
Pseudorapidity Dependence of Anisotropic Azimuthal Flow with the ALICE Detector
DEFF Research Database (Denmark)
Hansen, Alexander Colliander
In ultra-relativistic heavy-ion collisions a new state of matter known as the strongly interacting quark-gluon plasma (sQGP) is produced. A key observable in the study of the sQGP is anisotropic azimuthal ow. The anisotropies are described by ow harmonics, vn. In this thesis, bias arising from non...
Anisotropic behavior of quantum transport in graphene superlattices
DEFF Research Database (Denmark)
Pedersen, Jesper Goor; Cummings, Aron W.; Roche, Stephan
2014-01-01
We report on the possibility to generate highly anisotropic quantum conductivity in disordered graphene-based superlattices. Our quantum simulations, based on an efficient real-space implementation of the Kubo-Greenwood formula, show that in disordered graphene superlattices the strength of multi...
Properties and evolution of anisotropic structures in collisionless plasmas
Karimov, A R; Stenflo, L
2016-01-01
A new class of exact electrostatic solutions of the Vlasov-Maxwell equations based on the Jeans's theorem is proposed for studying the evolution and properties of two-dimensional anisotropic plasmas that are far from thermodynamic equilibrium. In particular, the free expansion of a slab of electron-ion plasma into vacuum is investigated.
Anisotropic Fractional Brownian Random Fields as White Noise Functionals
Institute of Scientific and Technical Information of China (English)
Zhi-yuan Huang; Chu-jin Li
2005-01-01
This investigation aims at a new construction of anisotropic fractional Brownisn random fields by the white noise approach. Moreover, we investigate its distribution and sample properties (stationariness of increments, self-similarity, sample continuity) which will furnish some useful views to future applications.
Anisotropic Four-Dimensional NS-NS String Cosmology
Chen, C M; Mak, M K; Chen, Chiang-Mei
2001-01-01
An anisotropic (Bianchi type I) cosmology is considered in the four-dimensional NS-NS sector of low-energy effective string theory coupled to a dilaton and an axion-like $H$-field within a de Sitter-Einstein frame background. The time evolution of this Universe is discussed in both the Einstein and string frames.
Quark–gluon plasma phenomenology from anisotropic lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Skullerud, Jon-Ivar; Kelly, Aoife [Department of Mathematical Physics, Maynooth University, Maynooth, Co Kildare (Ireland); Aarts, Gert; Allton, Chris; Amato, Alessandro; Evans, P. Wynne M.; Hands, Simon [Department of Physics, Swansea University, Swansea SA2 8PP, Wales (United Kingdom); Burnier, Yannis [Institut de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne, CH–1015 Lausanne (Switzerland); Giudice, Pietro [Institut für Theoretische Physik, Universität Münster, D–48149 Münster (Germany); Harris, Tim; Ryan, Sinéad M. [School of Mathematics, Trinity College, Dublin 2 (Ireland); Kim, Seyong [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of); Lombardo, Maria Paola [INFN–Laboratori Nazionali di Frascati, I–00044 Frascati (RM) (Italy); Oktay, Mehmet B. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States); Rothkopf, Alexander [Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, D–69120 Heidelberg (Germany)
2016-01-22
The FASTSUM collaboration has been carrying out simulations of N{sub f} = 2 + 1 QCD at nonzero temperature in the fixed-scale approach using anisotropic lattices. Here we present the status of these studies, including recent results for electrical conductivity and charge diffusion, and heavy quarkonium (charm and beauty) physics.
Theory of Spin Waves in Strongly Anisotropic Magnets
DEFF Research Database (Denmark)
Lindgård, Per-Anker; Cooke, J. F.
1976-01-01
A new infinite-order perturbation approach to the theory of spin waves in strongly anisotropic magnets is introduced. The system is transformed into one with effective two-ion anisotropy and considerably reduced ground-state corrections. A general expression for the spin-wave energy, valid to any...
What is the Brillouin Zone of an Anisotropic Photonic Crystal?
Sivarajah, P; Ofori-Okai, B K; Nelson, K A
2015-01-01
The concept of the Brillouin zone (BZ) in relation to a photonic crystal fabricated in an optically anisotropic material is explored both experimentally and theoretically. In experiment, we used femtosecond laser pulses to excite THz polaritons and image their propagation in lithium niobate and lithium tantalate photonic crystal (PhC) slabs. We directly measured the dispersion relation inside PhCs and observed that the lowest bandgap expected to form at the BZ boundary forms inside the BZ in the anisotropic lithium niobate PhC. Our analysis shows that in an anisotropic material the BZ - defined as the Wigner-Seitz cell in the reciprocal lattice - is no longer bounded by Bragg planes and thus does not conform to the original definition of the BZ by Brillouin. We construct an alternative Brillouin zone defined by Bragg planes and show its utility in identifying features of the dispersion bands. We show that for an anisotropic 2D PhC without dispersion, the Bragg plane BZ can be constructed by applying the Wigne...
Cluster variation studies of the anisotropic exchange interaction model
King, T. C.; Chen, H. H.
The cluster variation method is applied to study critical properties of the Potts-like ferromagnetic anisotropic exchange interaction model. Phase transition temperatures, order parameter discontinuities and latent heats of the model on the triangular and the fcc lattices are determined by the triangle approximation; and those on the square and the sc lattices are determined by the square approximation.
Plasma resonance in anisotropic layered high-Tc superconductors
DEFF Research Database (Denmark)
Sakai, Shigeki; Pedersen, Niels Falsig
1999-01-01
The plasma resonance is described theoretically by the inductive coupling model for a large stacked Josephson-junction system such as the intrinsic Josephson-junction array in anisotropic high- T-c superconductors. Eigenmodes of the plasma oscillation are analytically described and a numerical...
EIGEN THEORY OF VISCOELASTIC MECHANICS FOR ANISOTROPIC SOLIDS
Institute of Scientific and Technical Information of China (English)
Guo Shaohua
2001-01-01
Anisotropic viscoelastic mechanics is studied under anisotropic subspace. It is proved that there also exist the eigen properties for viscoelastic medium. The modal Maxwell's equation,modal dynamical equation (or modal equilibrium equation) and modal compatibility equation are obtained. Based on them, a new theory of anisotropic viscoelastic mechanics is presented. The advantages of the theory are as follows: 1) the equations are all scalar, and independent of each other. The number of equations is equal to that of anisotropic subspaces, 2) no matter how complicated the anisotropy of solids may be, the form of the definite equation and the boundary condition are in common and explicit, 3) there is no distinction between the force method and the displacement method for statics, that is, the equilibrium equation and the compatibility equation are indistinguishable under the mechanical space, 4) each modal equation has a definite physical meaning, for example, the modal equations of order one and order two express the volume change and shear deformation respectively for isotropic solids, 5) there also exist the potential functions which are similar to the stress functions of elastic mechanics for viscoelastic mechanics, but they are not man-made, 6) the final solution of stress or strain is given in the form of modal superimposition, which is suitable to the proximate calculation in engineering.
Self-collimation in photonic crystals with anisotropic constituents
Institute of Scientific and Technical Information of China (English)
J. W. Haus; M. Siraj; P. Prasad; P. Markowicz
2007-01-01
@@ In a photonic crystal composed of anisotropic constituents we quantify the range of input angles and the degree of collimation of the beam inside the crystal. The optical properties of a photobleached 4-dimethylamino-N-methyl-4-stilbazolium-tosylate (DAST) crystal are used in our model to demonstrate the efficacy of the self-collimation features.
A new approach to electromagnetism in anisotropic spaces
Voicu-Brinzei, Nicoleta
2009-01-01
Anisotropy of a space naturally leads to direction dependent electromagnetic tensors and electromagnetic potentials. Starting from this idea and using variational approaches and exterior derivative formalism, we extend some of the classical equations of electromagnetism to anisotropic (Finslerian) spaces. The results differ from the ones obtained by means of the known approach in [3], [4].
Fourth-order discrete anisotropic boundary-value problems
Directory of Open Access Journals (Sweden)
Maciej Leszczynski
2015-09-01
Full Text Available In this article we consider the fourth-order discrete anisotropic boundary value problem with both advance and retardation. We apply the direct method of the calculus of variations and the mountain pass technique to prove the existence of at least one and at least two solutions. Non-existence of non-trivial solutions is also undertaken.
Anisotropic cosmological models and generalized scalar tensor theory
Indian Academy of Sciences (India)
Subenoy Chakraborty; Batul Chandra Santra; Nabajit Chakravarty
2003-10-01
In this paper generalized scalar tensor theory has been considered in the background of anisotropic cosmological models, namely, axially symmetric Bianchi-I, Bianchi-III and Kortowski–Sachs space-time. For bulk viscous ﬂuid, both exponential and power-law solutions have been studied and some assumptions among the physical parameters and solutions have been discussed.
On the question of creep of anisotropic polycrystals
Directory of Open Access Journals (Sweden)
Simonyan A. M.
2012-03-01
Full Text Available On the base of dislocation slip conception the rheological behaviour of anisotropic polycrystals at complex stress state is considered. It is assumed that the anisotropy of polycrystals takes the place as a result of uneven distribution of slip system directions because of uneven distribution of single crystal grain orientations.
Switch isotropic/anisotropic wettability via dual-scale rods
Directory of Open Access Journals (Sweden)
Yang He
2014-10-01
Full Text Available It is the first time to demonstrate the comparison of isotropic/anisotropic wettability between dual-scale micro-nano-rods and single-scale micro-rods. Inspired by the natural structures of rice leaf, a series of micro-nano-rods and micro-rods with different geometric parameters were fabricated using micro-fabrication technology. Experimental measured apparent contact angles and advancing and receding contact angles from orthogonal orientations were characterized. The difference of contact angles from orthogonal orientation on dual-scale rods was much smaller than those on single-scale rods in both static and dynamic situation. It indicated that the dual-scale micro-nano-rods showed isotropic wettability, while single-scale micro-rods showed anisotropic wettability. The switch of isotropic/anisotropic wettability could be illustrated by different wetting state and contact line moving. It offers a facial way to switch isotropic/anisotropic wettability of the surface via dual-scale or single-scale structure.
Debonding analyses in anisotropic materials with strain- gradient effects
DEFF Research Database (Denmark)
Legarth, Brian Nyvang
2012-01-01
A unit cell approach is adopted to numerically analyze the effect of plastic anisotropy on damage evolution in a micro-reinforced composite. The matrix material exhibit size effects and a visco-plastic anisotropic strain gradient plasticity model accounting for such size effects is adopted. A con...
Prestack exploding reflector modelling and migration for anisotropic media
Alkhalifah, Tariq Ali
2014-10-09
The double-square-root equation is commonly used to image data by downward continuation using one-way depth extrapolation methods. A two-way time extrapolation of the double-square-root-derived phase operator allows for up and downgoing wavefields but suffers from an essential singularity for horizontally travelling waves. This singularity is also associated with an anisotropic version of the double-square-root extrapolator. Perturbation theory allows us to separate the isotropic contribution, as well as the singularity, from the anisotropic contribution to the operator. As a result, the anisotropic residual operator is free from such singularities and can be applied as a stand alone operator to correct for anisotropy. We can apply the residual anisotropy operator even if the original prestack wavefield was obtained using, for example, reverse-time migration. The residual correction is also useful for anisotropic parameter estimation. Applications to synthetic data demonstrate the accuracy of the new prestack modelling and migration approach. It also proves useful in approximately imaging the Vertical Transverse Isotropic Marmousi model.
Switch isotropic/anisotropic wettability via dual-scale rods
He, Yang; Jiang, Chengyu; Wang, Shengkun; Ma, Zhibo; Yuan, Weizheng
2014-10-01
It is the first time to demonstrate the comparison of isotropic/anisotropic wettability between dual-scale micro-nano-rods and single-scale micro-rods. Inspired by the natural structures of rice leaf, a series of micro-nano-rods and micro-rods with different geometric parameters were fabricated using micro-fabrication technology. Experimental measured apparent contact angles and advancing and receding contact angles from orthogonal orientations were characterized. The difference of contact angles from orthogonal orientation on dual-scale rods was much smaller than those on single-scale rods in both static and dynamic situation. It indicated that the dual-scale micro-nano-rods showed isotropic wettability, while single-scale micro-rods showed anisotropic wettability. The switch of isotropic/anisotropic wettability could be illustrated by different wetting state and contact line moving. It offers a facial way to switch isotropic/anisotropic wettability of the surface via dual-scale or single-scale structure.
Inversions for MT data in 2D symmetrical anisotropic media
Institute of Scientific and Technical Information of China (English)
YANG Chang-fu; LIN Chang-you; SUN Chong-chi; LI Qing-he
2005-01-01
In the paper, a 2D symmetrical anisotropic medium whose strike agrees with one of the horizontal principal axes is considered to develop a corresponding inversion technique. In the specified conditions, if we assume an equivalent conductivity anisotropy in both the vertical and dipping directions, i.e., σzz=σyy, the differential equations obtained are formally the same as that for TE and TM modes in the 2D isotropic geoelectrical media. The same inversion technique as that in the 2D isotropic media can be employed to obtain the anisotropic conductivities. It means that the TE and TM inversion results in the isotropic media can be respectively thought as the resistivities in the two principal directions of the symmetrically anisotropic media, which has offered a new approach and a theoretical guidance for interpreting magnetotelluric data. And the inversion technique developed here is used to test the magnetotelluric data in the area of Tianzhu and Yongdeng in Gansu Province, so that the crust anisotropic geoelectrical structures in this region can be obtained.
POLYNOMIAL PRESERVING RECOVERY FOR ANISOTROPIC AND IRREGULAR GRIDS
Institute of Scientific and Technical Information of China (English)
Zhimin Zhang
2004-01-01
Some properties of a newly developed polynomial preserving gradient recovery technique are discussed. Both practical and theoretical issues are addressed. Bounded-ness property is considered especially under anisotropic grids. For even-order finite element space, an ultra-convergence property is established under translation invariant meshes; for linear element, a superconvergence result is proven for unstructured grids generated by the Delaunay triangulation.
Ray-optics analysis of inhomogeneous optically anisotropic media
Sluijter, M.
2010-01-01
When the optical behavior of light in a medium depends on the direction in which light is traveling, the medium is called optically anisotropic. Light is an electromagnetic wave and in this thesis, we discuss the electromagnetic theory on optical anisotropy. We do this with the assumption that the w
Autofocus imaging : Experimental results in an anisotropic austenitic weld
Zhang, J.; Drinkwater, B.W.; Wilcox, P.D.; Hunter, A.J.
2012-01-01
The quality of an ultrasonic array image, especially for anisotropic material, depends on accurate information about acoustic properties. Inaccuracy of acoustic properties causes image degradation, e.g., blurring, errors in locating of reflectors and introduction of artifacts. In this paper, for an
Fourth-order discrete anisotropic boundary-value problems
2015-01-01
In this article we consider the fourth-order discrete anisotropic boundary value problem with both advance and retardation. We apply the direct method of the calculus of variations and the mountain pass technique to prove the existence of at least one and at least two solutions. Non-existence of non-trivial solutions is also undertaken.
Average widths of anisotropic Besov-Wiener classes
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
This paper concerns the problem of average σ-K width and average σ-L width of some anisotropic Besov-Wiener classes Srp q θb(Rd) and Srp q θB(Rd) in Lq(Rd) (1≤q≤p＜∞). The weak asymptotic behavior is established for the corresponding quantities.
Average widths of anisotropic Besov-Wiener classes
Institute of Scientific and Technical Information of China (English)
蒋艳杰
2000-01-01
This paper concems the problem of average σ-K width and average σ-L width of some anisotropic Besov-wiener classes Spqθr(Rd) and Spqθr(Rd) in Lq(Rd) (1≤≤q≤p<∞). The weak asymptotic behavior is established for the corresponding quantities.
Anisotropic Nanocolloids: self-assembly, interfacial adsorption, and electrostatic screening
de Graaf, J.
2012-01-01
In this thesis we consider the influence of anisotropy on the behaviour of colloids using theory and simulations. The recent increase in the ability to synthesize anisotropic particles (cubes, caps, octapods, etc.) has led to samples of sufficient quality to perform self-assembly experiments. Our in
Anisotropic uniqueness classes for a degenerate parabolic equation
Energy Technology Data Exchange (ETDEWEB)
Vil' danova, V F [Bashkir State Pedagogical University, Ufa (Russian Federation); Mukminov, F Kh [Bashkir State University, Ufa (Russian Federation)
2013-11-30
Anisotropic uniqueness classes of Tacklind type are identified for a degenerate linear parabolic equation of the second order in an unbounded domain. The Cauchy problem and mixed problems with boundary conditions of the first and third type are considered. Bibliography: 18 titles.
S-nitrosylation/Denitrosylation and Apoptosis of Immune Cells
Institute of Scientific and Technical Information of China (English)
Shaojin Duan; Chang Chen
2007-01-01
Nitric oxide (NO) as an immunoregulatory molecule, predominantly depending on S-nitrosylation, acts as a versatile player that executes its regulation and signal transduction for exerting its multi-functions and pleiotropy.Apoptosis of immune cells is an intricate process coupled with positive/negative selection depending on integrated diverse endogenous and exogenous signals and functions to sustain homeostasis in the immune system. Here, the dual roles of NO depending on its concentration in apoptosis are reviewed, breeding up a switch mode in the apoptotic process. Following comments of different switches from apoptosis-death, a new finding of checkpoint(early fluorescence point) of GSNO-initiated thymocyte apoptosis and NOS-GSNOR double control are highlighted.Moreover, S-nitrosylation/denitrosylation, being as a redox switch, logically approaches to networks of metabolism itself and further accesses the neuroendicrine-immune-free radical network as a whole. Moreover, the host defense mediated by NO on pathogens, via protein S-nitrosylation are also discussed.
Relationship between ascorbyl radical intensity and apoptosis-inducing activity.
Sakagami, H; Satoh, K; Ohata, H; Takahashi, H; Yoshida, H; Iida, M; Kuribayashi, N; Sakagami, T; Momose, K; Takeda, M
1996-01-01
Ascorbic acid and its related compounds were compared for their ascorbyl radical intensity and apoptosis-inducing activity. Sodium L-ascorbate, L-ascorbic acid, D-isoascorbic acid, sodium 6-beta-O-galactosyl-L-ascorbate and sodium 5,6-benzylidene-L-ascorbate, at the concentration of 1-10 mM, induced apoptotic cell death characterized by cell shrinkage, nuclear fragmentation and internucleosomal DNA cleavage in human promyelocytic leukemic HL-60 cells. On the other hand, L-ascorbic acid-2-phosphate magnesium salt and L-ascorbic acid 2-sulfate did not induce any of these apoptosis-associated characteristics. ESR measurements revealed that all the active compounds were progressively degraded, producing the ascorbyl radical (g = 2.0064, hfc = 0.17 mT) in culture medium, whereas the inactive compounds were stable and did not produce the ascorbyl radical. Cytotoxicity began to appear when the radical intensity exceeded a certain threshold level. In the presence of N-acetyl-L-cysteine, both ascorbyl radical intensity and apoptosis-inducing activity were significantly reduced. These data suggest the possible involvement of the ascorbyl radical in apoptosis induction by ascorbic acid-related compounds. Exposure of HL-60 cells to ascorbic acid or its active derivatives resulted in the rapid elevation of intracellular Ca2+ concentration, which might serve as the initial signal leading to the cell death pathway.
DEFF Research Database (Denmark)
Torp, Kristian
2009-01-01
Congestion is a major problem in most cities and the problem is growing (Quiroga, 2000) (Faghri & Hamad, 2002). When the congestion level is increased the drivers notice this as delays in the traffic (Taylor, Woolley, & Zito, 2000), i.e., the travel time for the individual driver is simply...... increased. In the initial study presented here, the time it takes to pass an intersection is studied in details. Two major signal-controlled four-way intersections in the center of the city Aalborg are studied in details to estimate the congestion levels in these intersections, based on the time it takes...
Anisotropic thermal conduction with magnetic fields in galaxy clusters
Arth, Alexander; Dolag, Klaus; Beck, Alexander; Petkova, Margarita; Lesch, Harald
2015-08-01
Magnetic fields play an important role for the propagation and diffusion of charged particles, which are responsible for thermal conduction. In this poster, we present an implementation of thermal conduction including the anisotropic effects of magnetic fields for smoothed particle hydrodynamics (SPH). The anisotropic thermal conduction is mainly proceeding parallel to magnetic fields and suppressed perpendicular to the fields. We derive the SPH formalism for the anisotropic heat transport and solve the corresponding equation with an implicit conjugate gradient scheme. We discuss several issues of unphysical heat transport in the cases of extreme ansiotropies or unmagnetized regions and present possible numerical workarounds. We implement our algorithm into the cosmological simulation code GADGET and study its behaviour in several test cases. In general, we reproduce the analytical solutions of our idealised test problems, and obtain good results in cosmological simulations of galaxy cluster formations. Within galaxy clusters, the anisotropic conduction produces a net heat transport similar to an isotropic Spitzer conduction model with low efficiency. In contrast to isotropic conduction our new formalism allows small-scale structure in the temperature distribution to remain stable, because of their decoupling caused by magnetic field lines. Compared to observations, strong isotropic conduction leads to an oversmoothed temperature distribution within clusters, while the results obtained with anisotropic thermal conduction reproduce the observed temperature fluctuations well. A proper treatment of heat transport is crucial especially in the outskirts of clusters and also in high density regions. It's connection to the local dynamical state of the cluster also might contribute to the observed bimodal distribution of cool core and non cool core clusters. Our new scheme significantly advances the modelling of thermal conduction in numerical simulations and overall gives
Effective wavefield extrapolation in anisotropic media: Accounting for resolvable anisotropy
Alkhalifah, Tariq Ali
2014-04-30
Spectral methods provide artefact-free and generally dispersion-free wavefield extrapolation in anisotropic media. Their apparent weakness is in accessing the medium-inhomogeneity information in an efficient manner. This is usually handled through a velocity-weighted summation (interpolation) of representative constant-velocity extrapolated wavefields, with the number of these extrapolations controlled by the effective rank of the original mixed-domain operator or, more specifically, by the complexity of the velocity model. Conversely, with pseudo-spectral methods, because only the space derivatives are handled in the wavenumber domain, we obtain relatively efficient access to the inhomogeneity in isotropic media, but we often resort to weak approximations to handle the anisotropy efficiently. Utilizing perturbation theory, I isolate the contribution of anisotropy to the wavefield extrapolation process. This allows us to factorize as much of the inhomogeneity in the anisotropic parameters as possible out of the spectral implementation, yielding effectively a pseudo-spectral formulation. This is particularly true if the inhomogeneity of the dimensionless anisotropic parameters are mild compared with the velocity (i.e., factorized anisotropic media). I improve on the accuracy by using the Shanks transformation to incorporate a denominator in the expansion that predicts the higher-order omitted terms; thus, we deal with fewer terms for a high level of accuracy. In fact, when we use this new separation-based implementation, the anisotropy correction to the extrapolation can be applied separately as a residual operation, which provides a tool for anisotropic parameter sensitivity analysis. The accuracy of the approximation is high, as demonstrated in a complex tilted transversely isotropic model. © 2014 European Association of Geoscientists & Engineers.
Viscous inclusions in anisotropic materials: Theoretical development and perspective applications
Jiang, Dazhi
2016-12-01
Theories and numerical solutions for a viscous ellipsoid in an infinite anisotropic viscous medium subjected to far-field homogeneous deformation lie at the heart of self-consistent homogenization models and multiscale simulations of texture and fabric development in Earth's lithosphere. There is considerable literature on ellipsoid inclusions, focused on anisotropic elastic materials, published in multi-disciplinary fields. To make this body of work more accessible as well as to advance viscous inclusion studies, an effort is made here to summarize recent advances and to further develop formally more explicit and, where possible, analytic solutions for incompressible viscous materials. The point-force concept and equivalent inclusion method of Eshelby are used together with the Green function approach. This leads to generalized equations for ellipsoid inclusion behaviors in anisotropic materials. In the particular case of isotropic materials, the new mathematical development here enables the use of existing methods for elastic materials to get solutions for corresponding viscous inclusion problems efficiently and accurately. A 2D formulation is also presented for elliptic cylinders in plane-straining flows of anisotropic materials, using the same Green function method that is adopted for 3D inclusions. The 2D formulation is benchmarked with existing analytic solutions. A reconnaissance investigation to compare the behaviors of 2D elliptic inclusions and triaxial ellipsoids in a matrix of planar anisotropy undergoing far-field plane-straining flows suggests that conclusions drawn from 2D cannot be applied to 3D in anisotropic cases. The application of the viscous inclusion theory to the rheologically heterogeneous and non-linear lithosphere is discussed. By regarding a heterogeneous element as an ellipsoidal inclusion embedded in a hypothetical homogeneous equivalent matrix whose effective rheology is obtained through micromechanical homogenization and assuming
Mulvey, Christine S.; Sherwood, Carly A.; Bigio, Irving J.
2009-11-01
Apoptosis-programmed cell death-is a cellular process exhibiting distinct biochemical and morphological changes. An understanding of the early morphological changes that a cell undergoes during apoptosis can provide the opportunity to monitor apoptosis in tissue, yielding diagnostic and prognostic information. There is avid interest regarding the involvement of apoptosis in cancer. The initial response of a tumor to successful cancer treatment is often massive apoptosis. Current apoptosis detection methods require cell culture disruption. Our aim is to develop a nondisruptive optical method to monitor apoptosis in living cells and tissues. This would allow for real-time evaluation of apoptotic progression of the same cell culture over time without alteration. Elastic scattering spectroscopy (ESS) is used to monitor changes in light-scattering properties of cells in vitro due to apoptotic morphology changes. We develop a simple instrument capable of wavelength-resolved ESS measurements from cell cultures in the backward direction. Using Mie theory, we also develop an algorithm that extracts the size distribution of scatterers in the sample. The instrument and algorithm are validated with microsphere suspensions. For cell studies, Chinese hamster ovary (CHO) cells are cultured to confluence on plates and are rendered apoptotic with staurosporine. Backscattering measurements are performed on pairs of treated and control samples at a sequence of times up to 6-h post-treatment. Initial results indicate that ESS is capable of discriminating between treated and control samples as early as 10- to 15-min post-treatment, much earlier than is sensed by standard assays for apoptosis. Extracted size distributions from treated and control samples show a decrease in Rayleigh and 150-nm scatterers, relative to control samples, with a corresponding increase in 200-nm particles. Work continues to correlate these size distributions with underlying morphology. To our knowledge, this
Munzarova, Helena; Plomerova, Jaroslava; Kissling, Edi
2015-04-01
Considering only isotropic wave propagation and neglecting anisotropy in teleseismic tomography studies is a simplification obviously incongruous with current understanding of the mantle-lithosphere plate dynamics. Furthermore, in solely isotropic high-resolution tomography results, potentially significant artefacts (i.e., amplitude and/or geometry distortions of 3D velocity heterogeneities) may result from such neglect. Therefore, we have undertaken to develop a code for anisotropic teleseismic tomography (AniTomo), which will allow us to invert the relative P-wave travel time residuals simultaneously for coupled isotropic-anisotropic P-wave velocity models of the upper mantle. To accomplish that, we have modified frequently-used isotropic teleseismic tomography code Telinv (e.g., Weiland et al., JGR, 1995; Lippitsch, JGR, 2003; Karousova et al., GJI, 2013). Apart from isotropic velocity heterogeneities, a weak hexagonal anisotropy is assumed as well to be responsible for the observed P-wave travel-time residuals. Moreover, no limitations to orientation of the symmetry axis are prescribed in the code. We allow a search for anisotropy oriented generally in 3D, which represents a unique approach among recent trials that otherwise incorporate only azimuthal anisotopy into the body-wave tomography. The presented code for retrieving anisotropy in 3D thus enables its direct applications to datasets from tectonically diverse regions. In this contribution, we outline the theoretical background of the AniTomo anisotropic tomography code. We parameterize the mantle lithosphere and asthenosphere with an orthogonal grid of nodes with various values of isotropic velocities, as well as of strength and orientation of anisotropy in 3D, which is defined by azimuth and inclination of either fast or slow symmetry axis of the hexagonal approximation of the media. Careful testing of the new code on synthetics, concentrating on code functionality, strength and weaknesses, is a
Van der Waals interaction torque and force between dielectrically anisotropic layered media
Lu, Bing-Sui
2016-01-01
We analyse the van der Waals interaction for a pair of dielectrically anisotropic plane-layered media interacting across a dielectrically isotropic medium. We investigate the van der Waals torque and force for the following cases: (i) a pair of single anisotropic layers, (ii) a single anisotropic layer interacting with a multilayered slab consisting of alternating anisotropic and isotropic layers, and (iii) a pair of multilayered slabs each consisting of alternating anisotropic and isotropic layers, looking at the cases where the optical axes lie parallel and/or perpendicular to the plane of the layers. For the first case, the optical axes of the oppositely facing anisotropic layers of the two interacting slabs generally have an angular mismatch, and within each multilayered slab the optical axes may either be the same, or undergo constant angular increments across the anisotropic layers. In particular, we examine how the behaviors of the van der Waals torque and force can be "tuned" by adjusting the layer th...
Collective modes of an anisotropic quark-gluon plasma induced by relativistic jets
Mandal, Mahatsab
2012-01-01
We discuss the characteristics of collective modes induced by relativistic jets in an anisotropic quark-gluon plasma(AQGP). Assuming a tsunami-like initial jet distribution, it is found that the dispersion relations for both the stable and unstable modes are modified substantially due to the passage of jet compared to the case when there is no jet. It has also been shown that the growth rate of instability first increases compared to the no jet case and then completely turned into damping except the case when the jet velocity is perpendicular to the wave vector in which case the instability always grows. Thus, the introduction of the jet in the AQGP, in general, might to faster isotropization for the special case when the wave vector is parallel to the anisotropy axis.
Dijet induced collective modes in an anisotropic quark-gluon plasma
Mandal, Mahatsab
2012-01-01
We discuss the collective modes due to the propagation of two oppositely moving relativistic jets (dijet) in an anisotropic quark-gluon plasma(AQGP) and compare the results with the case of single jet propagation. Assuming a tsunami-like initial jet distribution, it is found that the dispersion relations for both the stable and unstable modes are altered significantly due to the passage of dijet compared to the case of single jet propagation. It has also been shown that the growth rate of instability, due to introduction of dijet in the system, increases compared to the case of single jet case. As in the case of single jet propagation, the instability always grows when the jet velocity is perpendicular to the wave vector. We, thus, argue that the introduction of dijet in the AQGP, in general, leads to faster isotropization (than single jet propagation) for the special case when the wave vector is parallel to the anisotropy axis.
An ultrasonic methodology to non-destructively estimate the grain orientation in an anisotropic weld
Directory of Open Access Journals (Sweden)
Wirdelius Håkan
2014-06-01
Full Text Available The initial step towards a non-destructive technique that estimates grain orientation in an anisotropic weld is presented in this paper. The purpose is to aid future forward simulations of ultrasonic NDT of this kind of weld to achieve a better result. A forward model that consists of a weld model, a transmitter model, a receiver model and a 2D ray tracing algorithm is introduced. An inversion based on a multi-objective genetic algorithm is also presented. Experiments are conducted for both P and SV waves in order to collect enough data used in the inversion. Calculation is conducted to fulfil the estimation with both the synthetic data and the experimental data. Concluding remarks are presented at the end of the paper.
Apoptosis in thymus of teleost fish.
Romano, Nicla; Ceccarelli, Giuseppina; Caprera, Cecilia; Caccia, Elisabetta; Baldassini, Maria Rosaria; Marino, Giovanna
2013-08-01
The presence and distribution of apoptotic cells during thymus development and in adult were studied by in situ end-labelling of fragmented DNA in three temperate species carp (Cyprinus carpio), sea bass (Dicentrarchus labrax) and dusky grouper (Epinephelus marginatus) and in the adult thymus of three Antarctic species belonging to the genus Trematomus spp. During thymus development some few isolated apoptotic cell (AC) firstly appeared in the central-external part of the organ (carp: 5 days ph; sea bass: 35 days ph grouper: 43 days ph). Initially the cells were isolated and then increased in number and aggregated in small groups in the outer-cortical region of the thymus larvae. The high density of apoptotic cells was observed in the junction between cortex and medulla from its appearance (border between cortex and medulla, BCM). ACs decreased in number in juveniles and adult as well as the ACs average diameter. In late juveniles and in adulthood, the apoptosis were restricted to the cortex. In Antarctic species the thymus is highly adapted to low temperature (high vascularisation to effort the circulation of glycoproteins enriched plasma and strongly compact parenchyma). The apoptosis process was more extended (4-7 fold) as compare with the thymus of temperate species, even if the distribution of ACs was similar in all examined species. Data suggested a common process of T lymphocyte negative-selection in BCM of thymus during the ontogeny. The selection process seems to be still active in adult polar fish, but restricted mainly in the cortex zone.