Influence of long-range dipolar interactions on the phase stability and hysteresis shapes of ferroelectric and antiferroelectric multilayers

Phase transition and field driven hysteresis evolution of a two-dimensional Ising grid consisting of ferroelectric-antiferroelectric multilayers that take into account the long range dipolar interactions were simulated by a Monte-Carlo method. Simulations were carried out for a 1+1 bilayer and a 5+5 superlattice. Phase stabilities of components comprising the structures with an electrostatic-like coupling term were also studied. An electrostatic-like coupling, in the absence of an applied field, can drive the ferroelectric layers towards 180º domains with very flat domain interfaces mainly due to the competition between this term and the dipole-dipole interaction. The antiferroelectric layers do not undergo an antiferroelectric-to-ferroelectric transition under the influence of an electrostatic-like coupling between layers as the ferroelectric layer splits into periodic domains at the expense of the domain wall energy. The long-range interactions become significant near the interfaces. For high periodicity structures with several interfaces, the interlayer long-range interactions substantially impact the configuration of the ferroelectric layers while the antiferroelectric layers remain quite stable unless these layers are near the Neel temperature. In systems investigated with several interfaces, the hysteresis loops do not exhibit a clear presence of antiferroelectricity that could be expected in the presence of anti-parallel dipoles, i. e., the switching takes place abruptly. Some recent experimental observations in ferroelectric-antiferroelectric multilayers are discussed where we conclude that the different electrical properties of bilayers and superlattices are not only due to strain effects alone but also long-range interactions. The latter manifests itself particularly in superlattices where layers are periodically exposed to each other at the interfaces

Prognostic factors determining recurrence in early-stage endometrial cancer

PubMedID: 23327055Objective: This study aimed to determine the clinically important prognostic factors for loco-regional or distant recurrence in early-stage endometrial cancer. Materials and Methods: This study complied with the Declaration of Helsinki, and the local ethics committee approved the study. Cases who underwent primary surgery of early-stage endometrial cancer at the Institution from 2000 to 2012 were reviewed retrospectively. Patients who did not detect recurrence were classified as group 1 (n = 200); those who detected recurrence were classified as group 2 (n = 23). Clinically prognostic factors were evaluated by univariate analyses. Results: The average age for group 2 (LUSI) was 63.8 years (p = 0.0001). Patients with grade 3 histology were all detected within group 2 (p = 0.0001). Endometrioid adenocarcinoma displaying squamous differentiation was found with a rate of 58.3% in group 2 (p = 0.0001). Lower uterine segment involvement (LUSI) and lymphovascular space invasion (LVSI) rates were 86.9% in group 2 (p = 0.0001). The rate of tumor size > 2 cm was 56.6% in group 2 (p = 0.0001). The median depth of myometrial invasion (DMI) was 5.1 mm (p = 0.034) and the average in myometrial thickness was 14.5 mm in group II (p = 0.0001). The percentage of myometrial invasion was 35.8% in Group II (p = 0.0001). Tumor free-distance was 9.4 mm in group II (p = 0.0001). Conclusion: Age and clinicopathological parameters of the tumours are significant predictors for recurrence in early-stage endometrial cancer

Effects of the depolarization field in a perforated film of the biaxial ferroelectric

The domain structure in a biaxial ferroelectric layer perforated by cylindrical channels has been investigated using the numerical simulation based on the phenomenological theory of ferroelectricity and the equations of electrostatics in the framework of the Gauss-Seidel iterative method. Both polar axes lie in the plane of the film, which is characteristic of thin epitaxial films of BaTiO3 and (Ba1-xSrx )TiO3 on a MgO substrate. The calculations have been performed using the parameters of BaTiO3, which does not matter because of the qualitative character of the results: the electrostatic problem is two-dimensional and formally applies to infinitely thick layers rather than to thin layers. The primary attention has been paid to the systems containing sixteen channels. Two different orientations of the polar axes with respect to the lattice channels have been considered. It has been shown that, for these orientations, the domain structure has a different character: when the line with the minimum distance between the channels is perpendicular to the bisector of the angle between the polar axes, this structure contains a single channel in the repeating motif and a polarization vortex; when one of the polar axes is perpendicular to the line with the minimum distance between the channels, the situation is less clear. There are indications that the repeating motif of the domain structure in a system of many channels contains two channels and does not contain vortices. The strong influence of the electrodes on the domain structure in this case has been noted

Clinical and Etiological evaluation of the children with chronic urticaria

Meeting of the European-Academy-of-Allergy-and-Clinical-Immunology -- JUN 11-15, 2016 -- Vienna, AUSTRIAKaya, Aysenur/0000-0002-8183-0190WOS: 000383679803092…European Acad Allergy & Clin Immuno

Allergic contact dermatitis to temporary black henna tattoo due to sensitization to paraphenylenediamine

Congress of the European-Academy-of-Allergy-and-Clinical-Immunology -- JUN 17-21, 2017 -- Helsinki, FINLANDWOS: 000408773104194…European Acad Allergy & Clin Immuno