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41.
<Emphasis Type="Italic">f</Emphasis>(<Emphasis Type="Italic">R</Emphasis>) global monopole revisited
Thiago R. P. Caramês Júlio C. Fabris E. R. Bezerra de Mello H. Belich 《The European Physical Journal C - Particles and Fields》2017,77(7):496
In this paper the f(R) global monopole is reexamined. We provide an exact solution for the modified field equations in the presence of a global monopole for regions outside its core, generalizing previous results. Additionally, we discuss some particular cases obtained from this solution. We consider a setup consisting of a possible Schwarzschild black hole that absorbs the topological defect, giving rise to a static black hole endowed with a monopole’s charge. Besides, we demonstrate how the asymptotic behavior of the Higgs field far from the monopole’s core is shaped by a class of spacetime metrics which includes the ones analyzed here. In order to assess the gravitational properties of this system, we analyze the geodesic motion of both massive and massless test particles moving in the vicinity of such configuration. For the material particles we set the requirements they have to obey in order to experience stable orbits. On the other hand, for the photons we investigate how their trajectories are affected by the gravitational field of this black hole. 相似文献
42.
Brustein VP Cavalcanti CL de Melo-Junior MR Correia MT Beltrão EI Carvalho LB 《Applied biochemistry and biotechnology》2012,166(2):268-275
Nowadays, there is an increase of investigations into the fibroadenoma, mainly because some studies have shown that the occurrence
of fibroadenoma is linked to an increased risk of developing breast carcinoma. Currently, the chemiluminescence biomarkers
are applied for validation methods and screening. Here, a lectin chemiluminescence is proposed as new histochemistry method
to identify carbohydrates in mammary tumoral tissues. The lectins concanavalin A (Con A) and peanut agglutinin (PNA) conjugated
to acridinium ester were used to characterize the glycocode of breast tissues: normal, fibroadenoma, and invasive duct carcinoma
(IDC). The lectin chemiluminescence expressed in relative light units (RLU) was higher in fibroadenoma and IDC than in normal
tissue for both lectins tested. The relationship RLU emission versus tissue area described a linear and hyperbolic curve for
IDC and fibroadenoma, respectively, using Con A whereas hyperbolic curves for both transformed tissues using PNA. RLU was
abolished by inhibiting the interaction between tissues and lectins using their specific carbohydrates: methyl-α-d-mannoside (Con A) and galactose (PNA). The intrinsic fluorescence emission did not change with combination of the lectins
(Con A/PNA) to the acridinium ester for hydrophobic residues. These results represent the lectin chemiluminescence as an alternative
of histochemistry method for tumoral diagnosis in the breast. 相似文献
43.
Abe Y Aberle C Akiri T dos Anjos JC Ardellier F Barbosa AF Baxter A Bergevin M Bernstein A Bezerra TJ Bezrukhov L Blucher E Bongrand M Bowden NS Buck C Busenitz J Cabrera A Caden E Camilleri L Carr R Cerrada M Chang PJ Chimenti P Classen T Collin AP Conover E Conrad JM Cormon S Crespo-Anadón JI Cribier M Crum K Cucoanes A D'Agostino MV Damon E Dawson JV Dazeley S Dierckxsens M Dietrich D Djurcic Z Dracos M Durand V Efremenko Y Elnimr M Endo Y Etenko A Falk E Fallot M Fechner M von Feilitzsch F 《Physical review letters》2012,108(13):131801
The Double Chooz experiment presents an indication of reactor electron antineutrino disappearance consistent with neutrino oscillations. An observed-to-predicted ratio of events of 0.944±0.016(stat)±0.040(syst) was obtained in 101 days of running at the Chooz nuclear power plant in France, with two 4.25 GW(th) reactors. The results were obtained from a single 10 m(3) fiducial volume detector located 1050 m from the two reactor cores. The reactor antineutrino flux prediction used the Bugey4 flux measurement after correction for differences in core composition. The deficit can be interpreted as an indication of a nonzero value of the still unmeasured neutrino mixing parameter sin(2)2θ(13). Analyzing both the rate of the prompt positrons and their energy spectrum, we find sin(2)2θ(13)=0.086±0.041(stat)±0.030(syst), or, at 90% C.L., 0.017相似文献
44.
Cynthia Regina Albrecht Mahl Rogrio Aparecido Bataglioli Guilherme Bedeschi Calais Thiago Bezerra Taketa Marisa Masumi Beppu 《Molecules (Basel, Switzerland)》2022,27(23)
The anomalous interaction between metal ions and the peptide beta-amyloid is one of the hallmarks of Alzheimer’s disease. Metal-binding biopolymers, including polysaccharides, can elucidate the fundamental aspects of metal ions’ interactions with biological tissue and their interplay in Alzheimer’s disease. This work focuses on the role of the alginate composition on Cu(II) adsorption in the presence of histidine or β-amyloid, the peptide associated with the progression of Alzheimer’s disease. Alginate samples with different mannuronic/guluronic (M/G) ratios led to similar Cu(II) adsorption capacities, following the Langmuir isotherm and the pseudo-second-order adsorption kinetic models. Although the presence of histidine produced up to a 20% reduction in the copper adsorption capacity in guluronic-rich alginate samples (M/G~0.61), they presented stable bidentate chelation of the metallic ion. Chemical analyses (FTIR and XPS) demonstrated the role of hydroxyl and carboxyl groups in copper ion chelation, whereas both crystallinity and morphology analyses indicated the prevalence of histidine interaction with guluronic-rich alginate. Similar results were observed for Cu(II) adsorption in alginate beads in the presence of beta-amyloid and histidine, suggesting that the alginate/histidine system is a simple yet representative model to probe the application of biopolymers to metal ion uptake in the presence of biological competitors. 相似文献
45.
Scale inhibitors based on phosphinepolycarboxylic acid (PPCA) have been successfully used in offshore oil production for preventing deposition of barium and strontium sulfates. A system was developed for the automated pretreatment of PPCA-containing water samples, followed on-line or off-line by phosphorus determination using ICP mass spectrometry. During pretreatment, the previously acidified inhibitor solution is adsorbed on a C18-reversed phase column and then eluted with 0.025 mol l−1 borate solution. Using a 3.5-ml sample volume, analytical frequency in the on-line mode is about 9 samples per hour and 17 in off-line operation. Detection limit of phosphorus in the borate solution was 0.20 μg l−1, using a crossflow nebulizer and a Ryton® spray chamber. Recoveries were, typically, in the range of 90% to 100% and repeatability about 5%. The method has been applied for monitoring inhibitor concentrations during laboratory and field squeeze tests. 相似文献
46.
Flank D.M. Bezerra Jacson Simsen Mariza S. Simsen 《Journal of Differential Equations》2019,266(7):3906-3924
In this work we study PDE limit problems for nonlinear reaction–diffusion equations and we study the sensitivity of nonlinear PDEs with respect to initial conditions and exponent parameters. Moreover, we prove continuity of the flow and weak upper semicontinuity of a family of global attractors for reaction–diffusion equations with spatially variable exponents when the exponents go to 2 in . 相似文献
47.
Antonia Torres Ávila Pimenta Raimundo Braz‐Filho Piero Giuseppe Delprete Elnatan Bezerra de Souza Edilberto Rocha Silveira Mary Anne Sousa Lima 《Magnetic resonance in chemistry : MRC》2010,48(9):734-737
Two unusual monoterpene indole alkaloids, stachyoside ( 1 ) and nor‐methyl‐23‐oxo‐correantoside ( 2 ), have been isolated from the aerial parts of Psychotria stachyoides. The structural elucidation of both compounds was performed by the aid of HRESIMS, FT‐IR, and 1D‐ and 2D‐NMR techniques including COSY, HSQC, HMBC, and NOESY. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
48.
Asymptotic behavior of solutions to a class of nonlocal non‐autonomous diffusion equations 下载免费PDF全文
F. D. M. Bezerra M. J. D. Nascimento S. H. da Silva 《Mathematical Methods in the Applied Sciences》2015,38(17):4317-4329
In this paper, we consider the nonlocal non‐autonomous evolution problems where Ω is a bounded smooth domain in , N≥1, β is a positive constant, the coefficient a is a continuous bounded function on , and K is an integral operator with symmetric kernel , being J a non‐negative function continuously differentiable on and . We prove the existence of global pullback attractor, and we exhibit a functional to evolution process generated by this problem that decreases along of solutions. Assuming the parameter β is small enough, we show that the origin is locally pullback asymptotically stable. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
49.
Macedo Jde S da Costa Júnior NB Almeida LE Vieira EF Cestari AR Gimenez Ide F Villarreal Carreño NL Barreto LS 《Journal of colloid and interface science》2006,298(2):515-522
Mesoporous activated carbon has been prepared from coconut coir dust as support for adsorption of some model dye molecules from aqueous solutions. The methylene blue (MB) and remazol yellow (RY) molecules were chosen for study of the adsorption capacity of cationic and anionic dyes onto prepared activated carbon. The adsorption kinetics was studied with the Lagergren first- and pseudo-second-order kinetic models as well as the intraparticle diffusion model. The results for both dyes suggested a multimechanism sorption process. The adsorption mechanisms in the systems dyes/AC follow pseudo-second-order kinetics with a significant contribution of intraparticle diffusion. The samples simultaneously present acidic and basic sites able to act as anchoring sites for basic and acidic dyes, respectively. Calorimetric studies reveal that dyes/AC interaction forces are correlated with the pH of the solution, which can be related to the charge distribution on the AC surface. These AC samples also exhibited very short equilibrium times for the adsorption of both dyes, which is an economically favorable requisite for the activated carbon described in this work, in addition to the local abundance of the raw material. 相似文献
50.
Korn Md Andrade JB Jesus DS Lemos VA Bandeira ML Santos WN Bezerra MA Amorim FA Souza AS Ferreira SL 《Talanta》2006,69(1):16-24
Lead is recognized worldwide as a poisonous metal. Thus, the determination of this element is often required in environmental, biological, food and geological samples. However, these analyses are difficult because such samples contain relatively low concentrations of lead, which fall below the detection limit of conventional analytical techniques such as flame atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry. Several preconcentration procedures to determine lead have therefore been devised, involving separation techniques such as liquid-liquid extraction, solid phase extraction, coprecipitation and cloud point extraction. Citing 160 references, this paper offers a critical review of preconcentration procedures for determining lead using spectroanalytical techniques. 相似文献