Relativistic models of magnetars: Nonperturbative analytical approach

In the present paper we focus on building simple nonperturbative analytical relativistic models of magnetars. With this purpose in mind we first develop a method for generating exact interior solutions to the static and axisymmetric Einstein-Maxwell-hydrodynamic equations with anisotropic perfect fluid and with pure poloidal magnetic field. Then using an explicit exact solution we present a simple magnetar model and calculate some physically interesting quantities as the surface elipticity and the total energy of the magnetized star.Comment: 10 pages, LaTe

Relativistic models of magnetars: structure and deformations

We find numerical solutions of the coupled system of Einstein-Maxwell's equations with a linear approach, in which the magnetic field acts as a perturbation of a spherical neutron star. In our study, magnetic fields having both poloidal and toroidal components are considered, and higher order multipoles are also included. We evaluate the deformations induced by different field configurations, paying special attention to those for which the star has a prolate shape. We also explore the dependence of the stellar deformation on the particular choice of the equation of state and on the mass of the star. Our results show that, for neutron stars with mass M = 1.4 Msun and surface magnetic fields of the order of 10^15 G, a quadrupole ellipticity of the order of 10^(-6) - 10^(-5) should be expected. Low mass neutron stars are in principle subject to larger deformations (quadrupole ellipticities up to 10^(-3) in the most extreme case). The effect of quadrupolar magnetic fields is comparable to that of dipolar components. A magnetic field permeating the whole star is normally needed to obtain negative quadrupole ellipticities, while fields confined to the crust typically produce positive quadrupole ellipticities.Comment: 25 pages, 9 figures, submitted to MNRA

Carga asociada a la administración de rivastigmina transdérmica y a su presentación oral en cuidadores de pacientes con enfermedad de Alzheimer

Introducción: La enfermedad de Alzheimer (EA) es la demencia más común en la vejez, y conlleva un elevado estrés y una importante carga familiar. Objetivo: Evaluar las diferencias en satisfacción y carga asociada a la administración de rivastigmina por vía transdérmica y oral en cuidadores de pacientes con EA. Material y métodos: Estudio observacional, transversal y multicéntrico que incluyó a cuidadores de pacientes con EA de leve a moderadamente grave tratados con rivastigmina. Se evaluó la molestia asociada a la administración, la carga soportada y la satisfacción con el tratamiento. Resultados: Se incluyeron 497 cuidadores/grupo. La edad media de los cuidadores fue de 58,1 ± 14,2 años, y cerca del 75% eran mujeres. La mayoría de cuidadores eran parientes cercanos. La dificultad para tragar la medicación supuso molestias medias o elevadas al 38,2% de los cuidadores del grupo oral, mientras que la dificultad para colocar el parche lo fue para el 4,6%. El tratamiento transdérmico alcanza molestias medias de 6,7 puntos y el oral de 10,1 (p <0,0001); la sobrecarga no mostró diferencias significativas (21,4 ± 7,2 frente a 21,5 ± 6,9, respectivamente). Respecto a la facilidad de uso, el 88,3% consideró fácil o muy fácil el parche, y el 71,2% la cápsula. La afectación de la vida del cuidador fue nula o muy ocasional en el 66,4% con tratamiento transdérmico, frente al 51,1% con tratamiento oral. El 75,1% se mostraron satisfechos con el tratamiento transdérmico, frente al 55,9% con el oral (p <0,0001). Conclusiones: Los cuidadores de pacientes con EA mostraron una mayor satisfacción con el tratamiento de rivastigmina transdérmica y menores molestias asociadas

Carga asociada a la administración de rivastigmina transdérmica y a su presentación oral en cuidadores de pacientes con enfermedad de Alzheimer

Introducción: La enfermedad de Alzheimer (EA) es la demencia más común en la vejez, y conlleva un elevado estrés y una importante carga familiar. Objetivo: Evaluar las diferencias en satisfacción y carga asociada a la administración de rivastigmina por vía transdérmica y oral en cuidadores de pacientes con EA. Material y métodos: Estudio observacional, transversal y multicéntrico que incluyó a cuidadores de pacientes con EA de leve a moderadamente grave tratados con rivastigmina. Se evaluó la molestia asociada a la administración, la carga soportada y la satisfacción con el tratamiento. Resultados: Se incluyeron 497 cuidadores/grupo. La edad media de los cuidadores fue de 58,1 ± 14,2 años, y cerca del 75% eran mujeres. La mayoría de cuidadores eran parientes cercanos. La dificultad para tragar la medicación supuso molestias medias o elevadas al 38,2% de los cuidadores del grupo oral, mientras que la dificultad para colocar el parche lo fue para el 4,6%. El tratamiento transdérmico alcanza molestias medias de 6,7 puntos y el oral de 10,1 (p <0,0001); la sobrecarga no mostró diferencias significativas (21,4 ± 7,2 frente a 21,5 ± 6,9, respectivamente). Respecto a la facilidad de uso, el 88,3% consideró fácil o muy fácil el parche, y el 71,2% la cápsula. La afectación de la vida del cuidador fue nula o muy ocasional en el 66,4% con tratamiento transdérmico, frente al 51,1% con tratamiento oral. El 75,1% se mostraron satisfechos con el tratamiento transdérmico, frente al 55,9% con el oral (p <0,0001). Conclusiones: Los cuidadores de pacientes con EA mostraron una mayor satisfacción con el tratamiento de rivastigmina transdérmica y menores molestias asociadas

Refolding of Aggregation-Prone ScFv Antibody Fragments Assisted by Hydrophobically Modified Poly(sodium acrylate) Derivatives

ScFv antibody fragments are a promising alternative to full-length antibodies for both therapeutic and diagnosis applications. They can be overexpressed in bacteria, which enables easy large scale production. Since scFv are artificial constructs, they are poorly soluble and prone to aggregation, which makes them difficult to manipulate and to refold. Here, stabilization and refolding of scFv fragments from urea-unfolded solutions are reported based on the use of micromolar amounts of polymers playing the role of artificial chaperons. Using fluorescence correlation spectroscopy, the size and aggregation number of complexes of scFv with unmodified or hydrophobically modified poly(sodium acrylate) are determined. The evolution of the secondary structure along the refolding procedure, in the presence or absence of 0.4 m L-arginine at scFv:polymerPeer reviewe

Residue management in double-crop systems: Impact on soybean growth and yield

Double-crop soybeans [Glycine max(L.) Merr.] have the potential to be a productive and profitable system. However, due to delayed planting, double-crop soybeans frequently experience lower yields and higher stress. Because planting is a major production constraint, a critical practice is the management of previous wheat residue. Trials were established in 2012, 2013, and 2014 in Saint Joseph, LA, and in 2013 and 2014 in Winnsboro, LA. The four residue management treatments investigated included conventionally tilled, planted into burned residue, planted into mowed residue, and planted into standing wheat residue. Vegetative and reproductive growth parameters, as well as yield, were used to evaluate the influence of residue management on productivity. Overall, residue management did not have a significant impact on early season growth parameters, except for plant height in 2012 at St. Joseph; however, it did significantly influence yield at both locations. In Saint Joseph in 2012, yields from planting into wheat residue were significantly lower than burned and mowed plots (1.2 compared with 2.8 and 2.7 Mg ha-1, respectively), and tilled treatments yielded significantly less than all three nontilled treatments in 2013 and 2014. In Winnsboro, planting into residue left on the soil surface resulted in significantly higher yields than when residue was removed. Overall, leaving residue on the soil surface provided stable yields across years and locations; however, not managing the residue can result in diminished yields. Therefore, practices such as mowing of wheat residue prior to planting provide an alternative to traditional no-till planting.Peer reviewedPlant and Soil Science

Properties of Graphene: A Theoretical Perspective

In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene from a theorist's perspective. We discuss the physical properties of graphene in an external magnetic field, reflecting the chiral nature of the quasiparticles near the Dirac point with a Landau level at zero energy. We address the unique integer quantum Hall effects, the role of electron correlations, and the recent observation of the fractional quantum Hall effect in the monolayer graphene. The quantum Hall effect in bilayer graphene is fundamentally different from that of a monolayer, reflecting the unique band structure of this system. The theory of transport in the absence of an external magnetic field is discussed in detail, along with the role of disorder studied in various theoretical models. We highlight the differences and similarities between monolayer and bilayer graphene, and focus on thermodynamic properties such as the compressibility, the plasmon spectra, the weak localization correction, quantum Hall effect, and optical properties. Confinement of electrons in graphene is nontrivial due to Klein tunneling. We review various theoretical and experimental studies of quantum confined structures made from graphene. The band structure of graphene nanoribbons and the role of the sublattice symmetry, edge geometry and the size of the nanoribbon on the electronic and magnetic properties are very active areas of research, and a detailed review of these topics is presented. Also, the effects of substrate interactions, adsorbed atoms, lattice defects and doping on the band structure of finite-sized graphene systems are discussed. We also include a brief description of graphane -- gapped material obtained from graphene by attaching hydrogen atoms to each carbon atom in the lattice.Comment: 189 pages. submitted in Advances in Physic

Helicobacter pylori Counteracts the Apoptotic Action of Its VacA Toxin by Injecting the CagA Protein into Gastric Epithelial Cells

Infection with Helicobacter pylori is responsible for gastritis and gastroduodenal ulcers but is also a high risk factor for the development of gastric adenocarcinoma and lymphoma. The most pathogenic H. pylori strains (i.e., the so-called type I strains) associate the CagA virulence protein with an active VacA cytotoxin but the rationale for this association is unknown. CagA, directly injected by the bacterium into colonized epithelium via a type IV secretion system, leads to cellular morphological, anti-apoptotic and proinflammatory effects responsible in the long-term (years or decades) for ulcer and cancer. VacA, via pinocytosis and intracellular trafficking, induces epithelial cell apoptosis and vacuolation. Using human gastric epithelial cells in culture transfected with cDNA encoding for either the wild-type 38 kDa C-terminal signaling domain of CagA or its non-tyrosine-phosphorylatable mutant form, we found that, depending on tyrosine-phosphorylation by host kinases, CagA inhibited VacA-induced apoptosis by two complementary mechanisms. Tyrosine-phosphorylated CagA prevented pinocytosed VacA to reach its target intracellular compartments. Unphosphorylated CagA triggered an anti-apoptotic activity blocking VacA-induced apoptosis at the mitochondrial level without affecting the intracellular trafficking of the toxin. Assaying the level of apoptosis of gastric epithelial cells infected with wild-type CagA+/VacA+ H. pylori or isogenic mutants lacking of either CagA or VacA, we confirmed the results obtained in cells transfected with the CagA C-ter constructions showing that CagA antagonizes VacA-induced apoptosis. VacA toxin plays a role during H. pylori stomach colonization. However, once bacteria have colonized the gastric niche, the apoptotic action of VacA might be detrimental for the survival of H. pylori adherent to the mucosa. CagA association with VacA is thus a novel, highly ingenious microbial strategy to locally protect its ecological niche against a bacterial virulence factor, with however detrimental consequences for the human host

Modelling the Effect of Temperature on Respiration Rate of Fresh Cut Papaya (Carica papaya L.) Fruits.

A respiration rate (RR) model based on Peleg’s equation was developed for predicting RRs of fresh cut papaya. Respiration data for fresh cut papaya at 3/4 maturity were generated at temperatures 5, 10, 15, 20, 25 and 30°C using a closed system. RRs was found to be significantly influenced by storage temperature and increased from 0.021 to 0.289 mL[O2]/kg·h and 0.063 to 0.393 mL[CO2]/kg·h as a function of O2 and CO2 gas concentrations, respectively. Peleg’s constant K 1 and K 2 were obtained from linear regression analysis using GraphPad Prism 5.0 software and regression coefficients have good fit with values close to unity. The model was verified to assess the capability of its predictability of the RRs over the temperatures. There was good agreement with the experimentally estimated RRs. Information derived from the model can contribute in the design of successful modified atmospheric systems for storage of fresh cut papaya