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Electrical spin injection into silicon was studied in a ferromagnet/insulator/silicon/insulator/ferromagnet structure, where the insulator is Si3N4. Si3N4 barriers conduct by hopping conduction at low voltages, but switch to Fowler-Nordheim tunneling at high voltages. In the Fowler-Nordheim tunneling regime a magnetic field dependence of the output current consistent with spin dependent transport through the silicon is observed; in the hopping conduction regime reduced magnetic field dependence of the output current is observed. This voltage dependence of the magnetic sensitivity strongly supports the existence of spin injection into silicon. After correction for Lorentz magnetoresistance, the magnitude of this signal is 4.1%±0.5% (12%±5%) for p-type (n-type) Si. [ABSTRACT FROM AUTHOR]

We describe a measurement technique for x-ray absorption spectroscopy, in which the sample is used as the detector. Co L[sub 2,3] absorption spectra were taken from cobalt films grown on n-GaAs by measuring the photovoltage generated by the x rays transmitted across the rectifying metalsemiconductor contact. After correcting the effects of signal saturation good agreement was obtained with spectra acquired using the conventional total electron yield method. X-ray magnetic circular dichroism measurements using the method gave values for the spin moment of cobalt between 1.48 and 1.89 µ[sub B]/atom, compared to the value in the literature of 1.55 ·[sub B]/atom for the bulk. An anomalously high average value of 0.39 ·[sub B]/atom was found for the orbital moment and attributed to the presence of oxide in the films. [ABSTRACT FROM AUTHOR]

The structure and surface tension of the liquid–vapor interface of a polar fluid are investigated using integral equation and perturbation theories. A recently introduced integro-differential equation and a perturbation theory are employed to determine the extent to which purely multipolar anisotropies in the pair potential induce orientational ordering. Both of these theories agree that orientational ordering can be induced at the liquid–vapor interface by purely multipolar anisotropies in the intermolecular potential. The Yvon–Born–Green equation and the virial equation for the surface tension are written in terms of the spherical harmonic coefficients of the one and two particle distributions, and simple expressions are obtained for the density profile and the anisotropic contribution to the surface tension for molecular models of multipolar symmetry. The density profiles, density-orientation profiles, surface thickness, and surface tension are calculated for the Stockmayer fluid for a range of temperatures and dipole moments. [ABSTRACT FROM AUTHOR]

The molecular dynamics method is used to study the liquid–vapor interface of the Stockmayer fluid. We compare our results for the singlet density-orientation distribution function and surface tension with the predictions of integral equation and perturbation theory. We find that at low temperature and high moment conditions, dipolar orientations in the interfacial region parallel to the surface are more probable. The pressure tensor, mean squared force, and mean squared torque are also determined as functions of position with respect to the interface. Directional anisotropy in the mobility of particles in the vicinity of the surface is found by decomposing the mean squared displacements into components parallel and perpendicular to the interfacial plane. [ABSTRACT FROM AUTHOR]

he infrared magnetorefractive effect (MRE) is used to compare the magnetoresistance (MR) in epitaxial thin films of Fe3O4 grown on MgO with (100) and (111) crystal orientations. The smaller MRE detected in the (111) film is shown to correlate with the smaller electrically measured MR, its behavior consistent with a lower density of antiphase boundaries in the (111) film. [ABSTRACT FROM AUTHOR]

In 2011, patches of lodged plants of Helianthus annuus (commercial sunflower) with stem lesions were observed in a commercial crop at Kingsthorpe, Queensland, Australia. Several species of Diaporthe were consistently isolated from the lesions. Diaporthe novem was identified by DNA sequence analysis. In following surveys, Diaporthe novem was found to be associated with other crop species including Cicer arietinum (chickpea), Glycine max (soybean), Lupinus alba (lupin), Sorghum bicolor (sorghum) Vicia faba (faba bean) and Vigna radiata (mungbean), and with the weed species Datura stramonium (common thornapple), Helianthus annuus (wild-type sunflower), Malva parviflora (small flowered mallow), Rapistrum rugosum (turnip weed), Sambucus gaudichaudiana (wild elderberry), Sisymbrium orientale (indian hedge mustard), Sonchus oleraceus (sowthistle), Verbena sp., Vicia sativa (common vetch), and Xanthium strumarium (noogoora burr). In pathogenicity tests, isolates of D. novem from sunflower were highly virulent when re-inoculated on commercial sunflower varieties. This study has identified D. novem as a frequent cause of stem canker of sunflower in the eastern cropping areas of Australia, and extends the known host range of D. novem. [ABSTRACT FROM AUTHOR]

Spatially resolved measurements of giant magnetoresistance (GMR) in a synthetic spin valve multilayer are demonstrated using an infrared charge-coupled device camera to remotely sense images of the sample temperature. The field-dependent emissivity of the spin valve is shown to be proportional to the GMR, and a sudden change in the apparent temperature of the material associated with the free layer rotation in an applied magnetic field is observed. The optical nature of this technique gives excellent potential for in situ monitoring and whole-wafer characterization of the magnetoresistance in spin valves on a spatial scale during growth. [ABSTRACT FROM AUTHOR]

Fe3O4 /GaAs hybrid structures have been studied using reflection high-energy electron diffraction (RHEED), x-ray photoelectron spectroscopy (XPS), x-ray magnetic circular dichroism (XMCD), and low-temperature vibrating-sample magnetometry (VSM). The samples were prepared by oxidizing epitaxial Fe thin films in a partial pressure of 5×10-5 mbar of oxygen at 500 K for 180 s. Clear RHEED patterns were observed, suggesting the epitaxial growth of Fe oxides with a cubic structure. The XPS spectra show that the oxides were Fe3O4 rather than γ-Fe2O3, as there were no shake-up satellites between the two Fe 2p peaks. This was further confirmed by the XMCD measurements, which show ferromagnetic coupling between the Fe cations, with no evidence of intermixing at the interface. The VSM measurements show that the films have a magnetic uniaxial anisotropy and a "quick" saturation property, with the easy axes along the [011] direction. This detailed study offers further insight into the structure, interface, and magnetic properties of this hybrid Fe3O4 /GaAs(100) structure as a promising system for spintronic application. [ABSTRACT FROM AUTHOR]

The evolution of magnetic phase and anisotropy of epitaxial half-metallic Fe3O4 ultrathin films on GaAs(100) has been studied using magneto-optical Kerr effect (MOKE) measurements. While no magnetic signal was detected below 1 nm, the film shows a superparamagnetic response at a thickness of around 1.6 nm. Ferromagnetic MOKE loops with strong in-plane anisotropies were observed above 2.0 nm. The films show a magnetic uniaxial anisotropy in a thickness range of about 2.0–6.0 nm with the easy axis along the [011] direction. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We present our recent simulated results on Cr (5 nm)/Cu (5 nm)/Co (5 nm)/Cu (3 nm)/Co (2 nm) pseudo-spin valve dots. The simulated results agree qualitatively with the experimental results. Three different sizes of elliptical dots, 150 nm × 105 nm, 175 nm × 70 nm, and 200 nm × 60 nm, were simulated. Our simulations show that in these types of dots magnetization reversal occurs by the formation of domain walls: 90° for 175 nm × 70 nm and 360° for 200 nm × 60 nm. No domain wall was observed in the reversal of the 150 nm × 105 nm dots. For such dots, the simulated loops show a small two-step reversal pattern with the thin upper layer partially reversing followed by complete reversal of both layers at higher fields. In the larger dots, a two-step reversal is clearly observed both in the simulation and experiment. [ABSTRACT FROM AUTHOR]

The infrared reflectance of (Co[sub 50]Fe[sub 50])[sub χ]-(Al[sub 2]O[sub 3])[sub 1-χ] granular films which exhibit tunneling magnetoresistance has been measured in the wavelength range 2-25 µm for compositions both above and below the critical percolation volume fraction. The modifications of the Al[sub 2]O[sub 3] Restrahlen reflection region are well accounted for in an effective medium model. In addition, frequency dependent changes of the reflection have been observed under the application of magnetic fields up to 12 kOe. At the longitudinal optic reflection edge around 9µm distinctive magnetic signatures are found below and above the percolation threshold φ[sub c] at χ = 0.17. [ABSTRACT FROM AUTHOR]

Micromagnetic simulations of ferromagnetic fine particle systems have been used to study the effect of various parameters on the hysteresis loops and on the ferromagnetic resonance (FMR) curves. Systematic calculations show that the effect of the dipolar interactions on such systems significantly differs from that introduced by the exchange interactions. It is important to note that the anisotropy and damping parameter also contribute to the FMR response. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Thermal-to-kinetic-to-electrical energy conversion is demonstrated through the use of a piezoelectric transducer (PZT) integrated within a section of an oscillating heat pipe (OHP) partially filled with water. The sealed PZT transducer was configured as a bow spring parallel to the dominant flow direction within the OHP. The bottom portion of the OHP was heated in increments of 50W, while its top portion was actively cooled via water blocks. At ~50W, the internal fluid started to oscillate at ~2–4Hz due to the non-uniform vapor pressure generated in the OHP evaporator. Low-frequency fluid “pulses” were observed to occur across the flexed, in-line piezoelectric transducer, resulting in its deflection and measureable voltage spikes ranging between 24 and 63mV. The OHP, while having its internal fluid enthalpy harvested, was found to still have an ultra-high thermal conductivity on-the- order of 10 kW/m K; however, its maximum operating heat load decreased due to the pressure drop introduced by the PZT material. The thermo-piezoelectric harvesting concept made possible via the thermally driven fluid oscillations within an OHP provides a passive method for combined energy harvesting and thermal management that is both scalable and portable. [ABSTRACT FROM AUTHOR]

Purpose: Injury to the proximal hamstring complex (PHC) is becoming more frequently diagnosed. Patients attending our tertiary referral centre demonstrated 'pathological changes' in the unaffected normal contralateral PHC on MRI. The prevalence of PHC pathology, however, has not been previously documented in the literature in asymptomatic subjects. It is the hypothesis of this study that the natural history of asymptomatic pathological change on MRI in the PHC is not clear. The aim is to quantify the natural history of PHC degeneration.Method: Two hundred and fifty-three consecutive patients with an asymptomatic PHC were reviewed retrospectively between 2009 and 2010. The PHC was assessed in multiple MRI planes by a specialist musculoskeletal consultant radiologist.Results: Five hundred and six proximal hamstrings complexes were reviewed. Eighty-nine patients (35 %) were radiological normal both sides, median age 51 years (range 13-88). Thirty-four patients (13 %) had unilateral pathology, median age 55 years (range 25-89). Of these, 3 patients (1 %) had presence of a complete tear, median age 81 years (range 72-87). Sixteen patients (7 %) had tendinosis, median age 60 years (range 37-78). Fifteen patients (6 %) had a unilateral partial tear, median age 57 years (range 35-78). One hundred and thirty patients (52 %) had bilateral pathology, median age 65 years (range 25-89). Fifty-three patients (21 %) had the presence of bilateral tendinopathy alone, median age 56 years (range 25-89). Twenty-seven patients (11 %) had a partial tear on one side and tendinosis on the other, median age 68 years (range 38-89). Thirty-nine patients (15 %) had evidence of bilateral partial tears, median age 63 years (range 36-89), with 52 % demonstrating a torn conjoined and semi-membranosus tendon. The remaining 48 % had either an isolated tear of the conjoined or the semi-membranosus (the more commonly injured tendon 74 % of the time). Four patients (2 %) had bilateral complete ruptures with a median age of 68 years (range 59-78). Six patients (2 %) had a complete tear on one side and a partial tear on the other, median age 68 years (range 34-83). One patient had a complete tear on one side and tendinosis on the other, age 81 years.Conclusion: There is a higher prevalence of pathology in the asymptomatic population, 15 % have bilateral partial tears, and 2 % have bilateral complete tears. The semi-membranosus being the most affected, this may help clinically stratify the need for surgical intervention.Level Of Evidence: I. [ABSTRACT FROM AUTHOR]

Legumes' sensitivity to salt is exacerbated under growth conditions requiring nitrogen fixation by the plant. Phosphorus (P) deficiency is widespread in legumes, especially common bean ( Phaseolus vulgaris L). To examine the performance of P. vulgaris under salt stress conditions, a field experiment was conducted using two recombinants inbred lines (RILs) 115 (P-deficiency tolerant) and 147 (P-deficiency susceptible), grown under different salinity levels (L) (1.56, 4.78, and 8.83 dS m−1 as LI, L2, and L3, respectively) and supplied with four P rates (0, 30, 60, and 90 kg ha−1 P as P0, P30, P60, and P90, respectively) in order to assess the impact of P on salt tolerance. Results indicate that growing both RILs at P60 or P90 under all salinity levels (especially L1) significantly increased total chlorophyll, carotenoids, total soluble sugars, total free amino acids, and proline. Increasing P supply up to P60 under all salinity levels significantly induced higher accumulation of P, K+, Ca2+ and Mg2+ leaves in both RILs. Based on quadratic response over all locations, the maximum seed yield of 1.465 t ha−1 could be obtained at application of P 81.0 kg ha-1 in RIL115, while seed yield of 1.275 t ha−1 could be obtained with P rate of 78.3 kg ha−1 in RIL147. RIL115 exhibited more salt-tolerance with positive consequence on plant biomass and grain yield stability. Improved salt tolerance through adequate P fertilization is likely a promising strategy to improve P. vulgaris salinity tolerance and thus productivity, a response that seems to be P-rate dependent. [ABSTRACT FROM AUTHOR]

Presents a study that described a mechanism which considers the effect of small magnetic properties on the spin diffusion length in a granular giant magnetoresistive (GMR) material. Classes of magnetic clusters in a granular GMR material; Details of the depolarization mechanism; Information on a numerical simulation of the jitterbug effect of the GMR.

Deals with a study which investigated the effect that growth temperature has on the shape, size, location, and segregation of the magnetic cobalt grains and the morphology of the surface. Information on giant magnetoresistance; Methodology of the study; Results and discussion.

Presents information on a study that observed giant magnetoresistance in bulk mechanically alloyed Co[sub30]Ag[sub70]. Experimental procedure; Experimental results and discussion; Conclusion.

Purpose: The hypothesis of this study is that all-polyethylene (APE) tibial implants offer a biomechanical profile similar to metal-backed tray (MBT). There are significant financial implications, in selected patient groups, if APE can be deemed to perform as well as MBT.Methods: Using a finite element analysis of CAD models provided by DePuy (Leeds), stress distributions were investigated for both an APE and MBT tibial implant. The performance was assessed for cancellous bone at 700 MPa (normal) and at 350 MPa (less stiff). Plots were recorded along the length of the tibia, showing the loads carried by the bone (cortical and cancellous), the implant interface, cement interface and the stem. von Mises stress distributions and percentage volumes were used to assess bone resorption and hence potential for failure (fracture).Results: Higher stress shielding (resorption) occurred around the keel and stem of the MBT revealing greater potential for bone loss in these areas. APE had no areas of bone resorption (being more flexible resulting in less stress shielding). The stiffer MBT carries a higher proportion of the load down the stem. MBT stress in cancellous bone is lower than APE, as load is distributed to the cortical rim. APE has a marginally favourable strain state in cancellous bone and spreads loads more at the cement interface than MBT.Conclusion: Modern-day APE bearings may be superior to previously designed implants due to improvements in manufacturing. In the correct patient group, this could offer substantial cost savings. [ABSTRACT FROM AUTHOR]

Diaporthe (syn. Phomopsis) species are well-known saprobes, endophytes or pathogens on a range of plants. Several species have wide host ranges and multiple species may sometimes colonise the same host species. This study describes eight novel Diaporthe species isolated from live and/or dead tissue from the broad acre crops lupin, maize, mungbean, soybean and sunflower, and associated weed species in Queensland and New South Wales, as well as the environmental weed bitou bush (Chrysanthemoides monilifera subsp. rotundata) in eastern Australia. The new taxa are differentiated on the basis of morphology and DNA sequence analyses based on the nuclear ribosomal internal transcribed spacer region, and part of the translation elongation factor-1α and ß-tubulin genes. The possible agricultural significance of live weeds and crop residues ('green bridges') as well as dead weeds and crop residues ('brown bridges') in aiding survival of the newly described Diaporthe species is discussed. [ABSTRACT FROM AUTHOR]

Thermal-to-electrical energy conversion was demonstrated using an oscillating heat pipe (OHP) filled with ferrofluid and equipped with an annular-type solenoid. The OHP was subjected to a 100 °C axial temperature difference allowing the ferrofluid to passively oscillate through the solenoid, thus accomplishing electromagnetic induction. The measured solenoid voltage consisted of aperiodic pulses with dominant frequencies between 2 and 5Hz and peak-to-peak amplitudes approaching 1mV. Despite exposure to the thermal and phase change cycling within the OHP, nanoparticle morphologies and magnetic properties of the ferrofluid remained intact. This energy harvesting method allows for combined thermal management and in-situ power generation. [ABSTRACT FROM AUTHOR]

Thermal-to-electrical energy conversion was demonstrated using an oscillating heat pipe (OHP) filled with ferrofluid and equipped with an annular-type solenoid. The OHP was subjected to a 100 °C axial temperature difference allowing the ferrofluid to passively oscillate through the solenoid, thus accomplishing electromagnetic induction. The measured solenoid voltage consisted of aperiodic pulses with dominant frequencies between 2 and 5 Hz and peak-to-peak amplitudes approaching 1 mV. Despite exposure to the thermal and phase change cycling within the OHP, nanoparticle morphologies and magnetic properties of the ferrofluid remained intact. This energy harvesting method allows for combined thermal management and in-situ power generation. [ABSTRACT FROM AUTHOR]

Nasal and paranasal malignant tumours account for less than 5% of all head and neck malignancies. Epithelial malignancies overwhelmingly predominate, with squamous cell carcinomas representing the most frequent histological subtype in this location. Soft-tissue sarcomas of the nasal cavity and paranasal sinuses are exceedingly rare. Here, we report two cases of myxoid liposarcomas that occurred in the nasal and paranasal regions, both of which presented diagnostic challenges and could not be diagnosed definitively from intraoperative frozen sections. These cases reinforce the notion that, while they are uncommon, sarcomas in general and liposarcomas in particular should still be considered as part of the differential diagnosis in patients presenting with obstructive symptoms in the nasal and paranasal sinuses. [ABSTRACT FROM AUTHOR]

Two-dimensional images of giant magnetoresistance (GMR) using an infrared (IR) camera in the 8-12 μm wavelength regime are presented. Remote imaging of GMR involves the use of an IR camera to remotely sense changes in the emissivity of a thin film when a magnetic field is applied through a change in effective temperature, which is shown to be approximately linearly related to the GMR. Operating in the longer wavelength regime offers advantages in the theoretical connection between emissivity and GMR and also in the matching of the peak wavelength of the radiated flux with sample temperature. The GMR images obtained at 8-12 μm demonstrate an improvement in the correlation between GMR and emissivity change over previous work performed at 3-5 μm. [ABSTRACT FROM AUTHOR]

Many peptide drugs are susceptible to chemical degradation. It has been demonstrated experimentally that complexing a polymer to a peptide can prevent its degradation; however, the mechanism behind the stabilizing effect is not known, making it difficult to design polymers specifically for this purpose. In this work, we have used molecular dynamics experiments to gain insight into the polymer's stabilizing effect. The system AcVYGNGA, a model peptide, which has been extensively studied experimentally, was explored both alone in various forms and complexed with poly(vinylpyrrolidone) (PVP). Results suggest that the peptide–polymer complex must have a secondary structure such that the polymer affects the critical degradation mechanism in two ways: a steric effect based on the polymer's size, and a structural effect by which the physical distance between the reacting atoms within the peptide is increased. These results will be used to develop a set of structure–property relations which can be included within an optimization framework to design new polymers for peptide stabilization. [ABSTRACT FROM AUTHOR]

The article focuses on devices related to the field of spin electronics. Everyday electronic devices manipulate carriers solely based on their charge, either positive or negative. Their operation ignores the fact that those carriers also have a spin, either spin up or spin down. Spin electronics aims to remedy this deficiency by manipulating the spin as well as the charge of the carrier in nano-scale devices. Spintronics goes beyond the simple use of magnetic fields to alter the movement of charge. Instead, spintronics determines and/or senses the spin orientation of the carriers by incorporating magnetic materials into conventional devices.

Electrical magnetoresistance measurements of spin dependent materials or devices are very difficult without surface damaging or sample contamination, especially for thin-film giant magnetoresistance (GMR) multilayers. Moreover, the in situ determination of the GMR profile is almost impossible using electrical measurements. We propose a novel experimental design that allows the convenient measurement of magnetoresistance profiles using a noncontact method based on the magnetorefractive effect. This technique is applicable to metallic samples or devices showing magnetotransport properties and is also suitable for in situ measurements. The experiment involves infrared (IR) reflectivity measurements as a function of the applied magnetic field. By introducing IR optical fibers, the experimental setup has been substantially simplified while the need for costly optical components and time consuming alignments has been eliminated. Theoretical simulations of this experiment are also presented prior to the introduction of the proposed design. [ABSTRACT FROM AUTHOR]

Assays of nitrate reductase activity (NRA), glutamine synthetase activity (GSA), and alkaline phosphatase activity (APA) were used to measure nitrate, ammonium, and phosphate assimilation in five macroalgal species in three estuaries of Waquoit Bay, Massachusetts, U. S. A., subject to different N loading rates. The NRA significantly increased as loading rates of nitrate increased in Cladophora vagabunda and Gracilaria tikvahiae, with C. vagabunda exhibiting the greatest response. The GSA was always higher than the recorded NRA activity, but did not respond to the nitrogen loading gradient in any of the macroalgal species. The APA depended on nitrogen load in Cladophora vagabunda only. The NRA increased as internal nitrogen pools increased in Cladophora vagabunda, Gracilaria tikvahiae, and Fucus vesiculosus. Higher percent tissue N and lower C : N were found in Cladophora vagabunda, Gracilaria tikvahiae, and Fucus vesiculosus in higher N estuaries. Increases in percent tissue N, and increases in NRA, were due to higher loads of nitrate entering the estuary. Increased nitrogen loads correlated to increased C : N in macroalgal tissue, which correlated to increased NRA in Cladophora vagabunda and Gracilaria tikvahiae. This link illustrates that these two opportunistic macroalgal species best access the available inorganic nitrate pool in estuaries subject to eutrophication in Waquoit Bay. [ABSTRACT FROM AUTHOR]