OvHV-2 glycoprotein B delivered by a recombinant BoHV-4 is immunogenic and induces partial protection against sheep-associated malignant catarrhal fever in a rabbit model

An efficacious vaccine for sheep-associated malignant catarrhal fever (SA-MCF) is important for the livestock industry. Research towards SA-MCF vaccine development is hindered by the absence of culture systems to propagate the causative agent, ovine herpesvirus-2 (OvHV-2), which means its genome cannot be experimentally modified to generate an attenuated vaccine strain. Alternative approaches for vaccine development are needed to deliver OvHV-2 antigens. Bovine herpesvirus 4 (BoHV-4) has been evaluated as a vaccine vector for several viral antigens with promising results. In this study, we genetically engineered BoHV-4 to express OvHV-2 glycoprotein B (gB) and evaluated its efficacy as an SA-MCF vaccine using a rabbit model. The construction of a viable recombinant virus (BoHV-4-ADTK-OvHV-2-gB) and confirmation of OvHV-2 gB expression were performed in vitro. The immunization of rabbits with BoHV-4-ADTK-OvHV-2-gB elicited strong humoral responses to OvHV-2 gB, including neutralizing antibodies. Following intra-nasal challenge with a lethal dose of OvHV-2, 42.9% of the OvHV-2 gB vaccinated rabbits were protected against SA-MCF, while all rabbits in the mock-vaccinated group succumbed to SA-MCF. Overall, OvHV-2 gB delivered by the recombinant BoHV-4 was immunogenic and partly protective against SA-MCF in rabbits. These are promising results towards an SA-MCF vaccine; however, improvements are needed to increase protection rates

On Predicting Mössbauer Parameters of Iron-Containing Molecules with Density-Functional Theory

The performance of six frequently used density functional theory (DFT) methods (RPBE, OLYP, TPSS, B3LYP, B3LYP*, and TPSSh) in the prediction of Mössbauer isomer shifts(δ) and quadrupole splittings (ΔEQ) is studied for an extended and diverse set of Fe complexes. In addition to the influence of the applied density functional and the type of the basis set, the effect of the environment of the molecule, approximated with the conducting-like screening solvation model (COSMO) on the computed Mössbauer parameters, is also investigated. For the isomer shifts the COSMO-B3LYP method is found to provide accurate δ values for all 66 investigated complexes, with a mean absolute error (MAE) of 0.05 mm s–1 and a maximum deviation of 0.12 mm s–1. Obtaining accurate ΔEQ values presents a bigger challenge; however, with the selection of an appropriate DFT method, a reasonable agreement can be achieved between experiment and theory. Identifying the various chemical classes of compounds that need different treatment allowed us to construct a recipe for ΔEQ calculations; the application of this approach yields a MAE of 0.12 mm s–1 (7% error) and a maximum deviation of 0.55 mm s–1 (17% error). This accuracy should be sufficient for most chemical problems that concern Fe complexes. Furthermore, the reliability of the DFT approach is verified by extending the investigation to chemically relevant case studies which include geometric isomerism, phase transitions induced by variations of the electronic structure (e.g., spin crossover and inversion of the orbital ground state), and the description of electronically degenerate triplet and quintet states. Finally, the immense and often unexploited potential of utilizing the sign of the ΔEQ in characterizing distortions or in identifying the appropriate electronic state at the assignment of the spectral lines is also shown

Polarization reversal electroluminescence at low frequencies in barium titanate crystals

Audiofrequency-induced electroluminescence in BaTiO<SUB>3</SUB> single crystals is studied as a function of the strength and the frequency of the applied field, the temperature of the crystal, the nature of the electrode material, and the biasing field. It is shown that this electroluminescence differs in characteristics and origin from the previously reported radiofrequency-induced electroluminescence and is intimately associated with polarization reversal

Textured growth of strontium ferrite thin films by sputtering

Study of M-type hexagonal ferrite films (BaFe12O19 and SrFe12O19) is drawing a lot of interest due to their potential applications. Ba ferrite films with perpendicular anisotropy have been studied due to their projected use in perpendicular recording media, magneto-optic recording media and in microwave/millimeter wave devices. The current interest in depositing these films with in plane anisotropy is for use in high density longitudinal recording media. There have been attempts to deposit these materials, mostly on crystalline substrates though without complete control over the orientation. We have for the first time deposited the sputtered strontium ferrite films and could vary the texture of the film to obtain both perpendicular and in plane anisotropy. It was found that the films prepared at lower rf power when annealed at temperatures greater than or equal to 800 degrees C showed perpendicular anisotropy while the films prepared with higher rf power after similar annealing showed in plane anisotropy. These films had been prepared without substrate heating during sputter deposition and the as deposited films were X-ray amorphous and were nonmagnetic. However, these 'as deposited' films when annealed, showed different textures depending on the deposition conditions, as if these deposition conditions leave some signature in the films, which eventually decides the texture of these films. The microstructural studies showed that though the 'as deposited' films were X-ray amorphous, oriented microcrystallites form during deposition, which could be controlling the texture at the time of complete crystallization during annealing

The effect of deposition and annealing conditions on textured growth of sputter-deposited strontium ferrite films on different substrates

M-type strontium ferrite films were prepared by radio-frequency (rf) sputtering on fused quartz substrates using different deposition conditions and were subjected to two different types of annealing treatments. The study showed that in addition to the deposition conditions such as rf power, oxygen to argon ratio in the sputtering gas, and target to substrate distance, the postdeposition annealing conditions also play an important role in determining the texture and properties of the films. The films with random orientation or with preferred c-axis orientation either normal to the film plane or in the film plane could be deposited depending on the process parameters chosen. The study carried out by depositing these films on different substrates such as Si(100), Si(111), sapphire(110), and Gd3Ga5O12(111) showed that though the nature of the substrates plays a role in determining the texture and properties of the films, such effects are less dominant in comparison to the effect of deposition and annealing conditions in the case of strontium ferrite films. (C) 199

Textured Growth of Strontium Ferrite Thin Films by Sputtering

Study of M-type hexagonal ferrite films (BaFe12O19 and SrFe12O19) is drawing a lot of interest due to their potential applications. Ba ferrite films with perpendicular anisotropy have been studied due to their projected use in perpendicular recording media, magneto-optic recording media and in microwave/millimeter wave devices. The current interest in depositing these films with in plane anisotropy is for use in high density longitudinal recording media. There have been attempts to deposit these materials, mostly on crystalline substrates though without complete control over the orientation. We have for the first time deposited the sputtered strontium ferrite films and could vary the texture of the film to obtain both perpendicular and in plane anisotropy. It was found that the films prepared at lower rf power when annealed at temperatures ≥ 800 °C showed perpendicular anisotropy while the films prepared with higher rf power after similar annealing showed in plane anisotropy. These films had been prepared without substrate heating during sputter deposition and the as deposited films were X-ray amorphous and were nonmagnetic. However, these "as deposited" films when annealed, showed different textures depending on the deposition conditions, as if these deposition conditions leave some signature in the films, which eventually decides the texture of these films. The microstructural studies showed that though the "as deposited" films were X-ray amorphous, oriented microcrystallites form during deposition, which could be controlling the texture at the time of complete crystallization during annealing

Surface layers on ferroelectric BaTiO<SUB>3</SUB> crystals

The rf induced electroluminescence emitted from a BaTiO<SUB>3</SUB> crystal surface is studied in detail as a function of temperature, voltage, frequency of the rf field, electrode material, etc. It is shown that electroluminescence is essentially produced in the surface layer which exists on BaTiO<SUB>3</SUB> crystals and is not associated with dipole reversal or domain rearrangement, although the dielectric properties of the bulk alter the light output considerably. The characteristics of the surface layer, which is shown to be a space charge layer, have been determined and the mechanism of electroluminescence elucidated

Development of pure and doped gamma ferric oxide

Optimum conditions and experimental details for the formation of v-Fe203 from goethite have been worked out. In another method, a cheap complexing medium of starch was employed for precipitating acicular ferrous oxalate, which on decomposition in nitrogen and subsequent oxidation yielded acicular y-Fe203. On the basis of thermal decomposition in dry and moist nitrogen, DTA, XRD, GC and thermodynamic arguments, the mechanism of decomposition was elucidated. New materials obtained by doping ~'-Fe203 with 1-16 atomic percent magnesium, cobalt, nickel and copper, were synthesised and characterizedCUSATBull. Mater. Sci., Vol. 6, No. 1, February 1984, pp. 59--64