Magnetic anisotropies in ultrathin iron films grown on the surface-reconstructed GaAs substrate

Magnetic anisotropies of epitaxial ultrathin iron films grown on the surface-reconstructed GaAs substrate were studied. Ferromagnetic resonance technique was exploited to determine magnetic parameters of the films in the temperature range of 4-300 K. Extraordinary angular dependence of the FMR spectra was explained by the presence of fourfold and twofold in-plane anisotropies. A strong in-plane uniaxial anisotropy with magnetic hard axis along the [1 1- 0] crystallographic direction is present at the GaAsFe (001) interface while a weak in-plane uniaxial anisotropy for the Fe grown on Au has its easy axis oriented along [1 1- 0]. A linear dependence of the magnetic anisotropies as a function of temperature suggests that the strength of the in-plane uniaxial anisotropy is affected by the magnetoelastic anisotropies and differential thermal expansion of contacting materials. © 2007 American Institute of Physics

Microscopic examination of placenta of rats prenatally exposed to Aloe barbadensis: A preliminary study

Aloe barbadensis is the most widely used both commercially and therapeutic properties. It has been used for an array of ailments since ancient times as a medicinal plant. There are more than 360 different species of Aloe. Its products have been used in health foods for medical and preservative purposes. The objective of this study was to search the effects of Aloe barbadensis on the rat's placenta. Gel form of Aloe barbadensis is used in the study. It is commercial, preserved but otherwise untreated form of Aloe Barbadensis gel capsul. Female Wistar Albino rats were divided into three groups. Placenta specimens from each groups were processed for the microscopic examination. Trophoblastic giant cells and spongiotrophoblasts were decreased in number after Aloe barbadensis; trophoblastic giant cells which showed degenerative changes. The nuclei of these giant cells were going degeneration characterized by pyknosis and bizarrely shaped. Extracellular matrix production around the cells was increased, thicker and more irregular basal membrane like formation around the cells. Decreased and abnormal vessel formation in labyrinth area was clear and reduced functional capacity of the trophoblastic barier. The study shows that, in the presence of Aloe barbadensis, relevant alterations associated with a possible compensatory adjustment to maintain adequate metabolic exchange take place in the structure of placenta. Our results also demonstrated that the exposure to Aloe barbadensis during pregnancy not led to fetal growth retardation, fetal death, abortion or teratogenic effect

Direct current electric stimulation in implant osseointegration: An experimental animal study with sheep

PubMedID: 22103684In an effort to obtain a high-quality bone-implant interface, several methods involving alteration of surface morphological, physicochemical, and biochemical properties are being investigated. The aim of our study was to increase the osseointegration rate and quality and decrease the waiting period of dental implants before loading by using a microelectric implant stimulator device. It imitates microelectrical signals, which occur in bone fractures described in terms of piezoelectric theory. A single dental implant (Zimmer Dental), 3.7 mm in diameter, was inserted into the tibia of sheep bilaterally. Twenty-four dental implants were inserted into 12 sheep. Implant on the tibia of each sheep was stimulated with 7.5 µA direct current (DC), while the other side did not receive any stimulation and served as a control. Animals were sacrificed 1, 2, and 3 months after implantation. Bone segments with implants were processed with unclassified method. The determination of new bone formation and osseointegration around the dental implants was investigated by means of undecalcified method, histomorphologically. No statistically significant difference in bone-to-implant contact (BIC) ratio, osteoblastic activity, and new bone formation was found between the stimulation group and the control group at the late phase of healing (4, 8, and 12 weeks). No evidence was found that electric stimulation with implanted 7.5 µA DC is effective at late phase implant osseointegration on a sheep experimental model

Magnetic anisotropies in ultrathin iron films grown on the surface-reconstructed GaAs substrate

Magnetic anisotropies of epitaxial ultrathin iron films grown on the surface-reconstructed GaAs substrate were studied. Ferromagnetic resonance technique was exploited to determine magnetic parameters of the films in the temperature range of 4-300 K. Extraordinary angular dependence of the FMR spectra was explained by the presence of fourfold and twofold in-plane anisotropies. A strong in-plane uniaxial anisotropy with magnetic hard axis along the [1 1- 0] crystallographic direction is present at the GaAsFe (001) interface while a weak in-plane uniaxial anisotropy for the Fe grown on Au has its easy axis oriented along [1 1- 0]. A linear dependence of the magnetic anisotropies as a function of temperature suggests that the strength of the in-plane uniaxial anisotropy is affected by the magnetoelastic anisotropies and differential thermal expansion of contacting materials. © 2007 American Institute of Physics

Magnetic anisotropies in ultrathin iron films grown on the surface-reconstructed GaAs substrate

Magnetic anisotropies of epitaxial ultrathin iron films grown on the surface-reconstructed GaAs substrate were studied. Ferromagnetic resonance technique was exploited to determine magnetic parameters of the films in the temperature range of 4-300 K. Extraordinary angular dependence of the FMR spectra was explained by the presence of fourfold and twofold in-plane anisotropies. A strong in-plane uniaxial anisotropy with magnetic hard axis along the [1 1- 0] crystallographic direction is present at the GaAsFe (001) interface while a weak in-plane uniaxial anisotropy for the Fe grown on Au has its easy axis oriented along [1 1- 0]. A linear dependence of the magnetic anisotropies as a function of temperature suggests that the strength of the in-plane uniaxial anisotropy is affected by the magnetoelastic anisotropies and differential thermal expansion of contacting materials. © 2007 American Institute of Physics

Magnetic anisotropies in ultrathin iron films grown on the surface-reconstructed GaAs substrate

Magnetic anisotropies of epitaxial ultrathin iron films grown on the surface-reconstructed GaAs substrate were studied. Ferromagnetic resonance technique was exploited to determine magnetic parameters of the films in the temperature range of 4-300 K. Extraordinary angular dependence of the FMR spectra was explained by the presence of fourfold and twofold in-plane anisotropies. A strong in-plane uniaxial anisotropy with magnetic hard axis along the [1 1- 0] crystallographic direction is present at the GaAsFe (001) interface while a weak in-plane uniaxial anisotropy for the Fe grown on Au has its easy axis oriented along [1 1- 0]. A linear dependence of the magnetic anisotropies as a function of temperature suggests that the strength of the in-plane uniaxial anisotropy is affected by the magnetoelastic anisotropies and differential thermal expansion of contacting materials. © 2007 American Institute of Physics