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The aim of the present study was to evaluate the efficacy of helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure and compare the results with those of a combined drugs and surgery regimen. A total of 70 patients with hydroxyapatite orbital implant exposure in 70 eyes were randomly divided into two groups: Helium-neon laser therapy (group A) and drugs plus surgery (group B). Each group contained 35 patients. The healing rates and times of the conjunctival wound were recorded and compared following helium-neon laser treatment or the drugs plus surgery regimen. Changes in the hydroxyapatite orbital implant prior to and following helium-neon laser irradiation were analyzed. A similar animal study was conducted using 24 New Zealand white rabbits, which received orbital implants and were then received drug treatment or helium-neon therapy. In the human experiment, the rates for conjunctival wound healing were 97.14% in group A and 74.29% in group B, with a significant difference between the groups (χ2=5.71, P<0.05). Patients with mild exposure were healed after 7.22±2.11 days of helium-neon laser therapy and 14.33±3.20 days of drugs plus surgery. A statistically significant difference was found between the groups (t=8.97, P<0.05). Patients with moderate to severe exposure were healed after 18.19±2.12 days of helium-neon laser therapy and 31.25±4.21 days of drugs plus surgery. The difference between the groups was statistically significant (t=7.91, P<0.05). Enhanced magnetic resonance imaging showed that the helium-neon laser therapy signifi- cantly promoted vascularization of the hydroxyapatite orbital implant. These results, combined with pathological findings in animals, which showed that a helium-neon laser promoted vascularization and had anti-inflammatory effects, suggest that helium-neon laser irradiation is an effective method for treating hydroxyapatite orbital implant exposure, thereby avoiding secondary surgery. [ABSTRACT FROM AUTHOR]

Picosecond switching of the staggered antiferromagnetic order is shown to be realizable through spin-transfer torques from a short current pulse. The coupled dynamics of sublattice magnetization is mapped onto a classical pendulum subject to gravity and a driving pulse, where switching occurs if the pendulum acquires sufficient kinetic energy during the pulse to overcome the maximum of the effective gravity potential. The optimal switching scheme is explored through the dependence of switch angle and magnetic loss on the duration and strength of the current pulse. The physics discussed here provides a general route towards multifunctional THz applications via the spin-transfer torque in antiferromagnetic materials. [ABSTRACT FROM AUTHOR]

The objective of this work is to understand and quantitatively model the diffusive transport in electrically gated nanofluidic channels suitable for applications in drug delivery. Specifically, this work analyzed gated molecular diffusion through simulation in nanochannels between two chambers with asymmetric concentrations under a number of different control variables including surface charge, channel structure, drug molecule charge number, and background ionic concentration. When the dimension of the fluidic channel is comparable to the thickness of electrical double layer, the potential generated by gating inside of the channel becomes significant, which allows control of charged molecular diffusion inside of the nanochannel through electrostatic repulsion and attraction. In this work, the diffusion of molecules through a nanochannel is simulated in planar and cylindrical nanochannels when applying a gate voltage in two different surface charging scenarios. The gated nanochannel structures were modeled in the finite element software (COMSOL Multiphysics). The simulation results indicate that a small applied voltage can alter the diffusion rate by many orders of magnitude under certain conditions. The cylindrical nanochannel showed the best control of diffusion of charged molecules due to the exclusion-enrichment effect inside the nanochannel. [ABSTRACT FROM AUTHOR]

We present a study on atomic ordering within individual grains in granular L10-FePt thin films using transmission electron microscopy techniques. The film, used as a medium for heat assisted magnetic recording, consists of a single layer of FePt grains separated by non-magnetic grain boundaries and is grown on an MgO underlayer. Using convergent-beam techniques, diffraction patterns of individual grains are obtained for a large number of crystallites. The study found that although the majority of grains are ordered in the perpendicular direction, more than 15% of them are multi-variant, or of in-plane c-axis orientation, or disordered fcc. It was also found that these multi-variant and in-plane grains have always grown across MgO grain boundaries separating two or more MgO grains of the underlayer. The in-plane ordered portion within a multi-variant L10-FePt grain always lacks atomic coherence with the MgO directly underneath it, whereas, the perpendicularly ordered portion is always coherent with the underlying MgO grain. Since the existence of multi-variant and in-plane ordered grains are severely detrimental to high density data storage capability, the understanding of their formation mechanism obtained here should make a significant impact on the future development of hard disk drive technology. [ABSTRACT FROM AUTHOR]

Collinear antiferromagnets (AFs) support two degenerate magnon excitations carrying opposite spin polarizations, by which magnons can function as electrons in various spin-related phenomena. In an insulating ferromagnet(F)/AF/F trilayer, we explore the magnon-mediated interlayer coupling by calculating the magnon thermal energy in the AF as a function of the orientations of the Fs. The effect manifests as an interlayer exchange interaction and a perpendicular magnetic anisotropy; they both depend on temperature and the AF thickness. In particular, the exchange interaction turns out to be antiferromagnetic at low temperatures and ferromagnetic at high temperatures, whose magnitude can be 10 - 100 v µ eV for nanoscale separations, allowing experimental verification. [ABSTRACT FROM AUTHOR]

Currently, the most common recording media used for heat assisted magnetic recording is granular L10 based FePt-C directly deposited on a highly texturedpolycrystalline MgO underlayer. In this study, a thin granular MgO-C interlayer is inserted between the MgO underlayer and the granular L10-FePt-C magnetic layer to control the grain size of the magnetic media. By varying the deposition conditions of the MgO-C interlayer, we can vary the size of the L10-ordered FePt grains from about 10.5 nm to 7.6nm, while keeping the carbon composition in the magnetic layer unchanged. With the optimized interlayer, the L10-FePt-C media of grain size to 7.6 nm shows good squareness and perpendicular coercivity of 47 kOe as well as an order parameter of S = 0.85. [ABSTRACT FROM AUTHOR]

A hybrid model incorporating two methods, i.e., the Potts model Monte Carlo and the level set method, is developed to simulate the templated growth of a two-phase CoPt/SiO2 thin film. Previously it was demonstrated experimentally that the film grown on the prefabricated template followed the pattern of the template, forming a highly ordered microstructure. The simulation in this study investigates the physical mechanism by which such film growth behavior occurs and which parameters dictate the resultant microstructure. To correctly represent the physical process, the interfacial energies between different phases and the rate of each microevent to occur were established through the simulated film deposition on a flat substrate and subsequent comparison to the experimental observations. With the established interfacial energy and rate of microevents, the resultant film microstructure grown on the templated substrate is found to strongly depend on the geometries of domes fabricated on the template. The dominant mechanism of the formation of the microstructure is shown to shift from the surface energy gradient controlled lateral diffusion in the initial stage of film growth, which formed the rudiment of the ordered microstructure, to an interfacial energy controlled process, which retained the ordered microstructure in the later stage. [ABSTRACT FROM AUTHOR]

Topologically protected magnetic structures such as skyrmions and domain walls (DWs) have drawn a great deal of attention recently due to their thermal stability and potential for manipulation by spin current, which is the result of chiral magnetic configurations induced by the interfacial Dzyaloshinskii-Moriya interaction (DMI). Designing devices that incorporate DMI necessitates a thorough understanding of how the interaction presents and can be measured. One approach is to measure growth asymmetry of chiral bubble domains in perpendicularly magnetized thin films, which has been described elsewhere by thermally activated DW motion. Here, we demonstrate that the anisotropic angular dependence of DW energy originating from the DMI is critical to understanding this behavior. Domains in Co/Ni multilayers are observed to preferentially grow into nonelliptical teardrop shapes, which vary with the magnitude of an applied in-plane field. We model the domain profile using energetic calculations of equilibrium shape via the Wulff construction, which serves as a new paradigm for describing chiral domains that explains both the teardrop shape and the reversal of growth symmetry at large fields. [ABSTRACT FROM AUTHOR]

The effect of second-order uniaxial anisotropy energy K2 on thermal stability and writability of perpendicular media has been studied. Due to the high orientation of crystalline easy axes, both energy barrier and dynamic coercivity of perpendicular media increases with K2. With relatively more increase in energy barrier, improvement of the tradeoff between thermal stability and writability can be achieved by Increasing K2. The field angle dependence with nonzero K2 is also quantitatively investigated. [ABSTRACT FROM AUTHOR]

Objective: To compare contrast-enhanced ultrasound and contrast-enhanced magnetic resonance imaging for the assessment of vascularization of hydroxyapatite orbital implants., Methods: Ten patients who underwent monthly contrast-enhanced ultrasound and contrast-enhanced magnetic resonance imaging following implantation were analyzed. The two modalities were compared according to their ability to visualize the progress of vascularization at monthly intervals., Results: There were no differences in the findings shown by these two methods. Contrast-enhanced ultrasound provided better visualization of the dynamic process of vascularization than contrast-enhanced magnetic resonance imaging. There were no significant differences in the areas and the time to completion of fibrovascular ingrowth observed by contrast-enhanced ultrasound and contrast-enhanced magnetic resonance imaging, indicating that the findings of these two examinations were consistently similar., Conclusions: Contrast-enhanced ultrasound is useful for the assessment of vascularization of hydroxyapatite orbital implants and provides better visualization of the dynamic process than contrast-enhanced MRI., (Copyright © 2014 Elsevier Inc. All rights reserved.)