Controlling spin-dependent tunneling by bandgap tuning in epitaxial rocksalt MgZnO films.

Widespread application of magnetic tunnel junctions (MTJs) for information storage has so far been limited by the complicated interplay between tunnel magnetoresistance (TMR) ratio and the product of resistance and junction area (RA). An intricate connection exists between TMR ratio, RA value and the bandgap and crystal structure of the barrier, a connection that must be unravelled to optimise device performance and enable further applications to be developed. Here, we demonstrate a novel method to tailor the bandgap of an ultrathin, epitaxial Zn-doped MgO tunnel barrier with rocksalt structure. This structure is attractive due to its good Δ1 spin filtering effect, and we show that MTJs based on tunable MgZnO barriers allow effective balancing of TMR ratio and RA value. In this way spin-dependent transport properties can be controlled, a key challenge for the development of spintronic devices.

[Radiotherapy for soft tissue sarcomas of extremities. Preliminary comparative dosimetric study of 3D conformal radiotherapy versus helical tomotherapy]. / Radiothérapie postopératoire des sarcomes des tissus mous des extrémités. Etude dosimétrique préliminaire comparative de la radiothérapie conformationnelle avec la tomothérapie hélicoïdale.

PURPOSE: To evaluate dosimetry of helicoidal tomotherapy versus three-dimensional conformal radiotherapy (3D-CRT) with and without IMRT for the treatment of soft tissue sarcoma (STS) of the thigh. METHODS AND PATIENTS: A retrospective study was performed for three patients who received 3D-CRT as adjuvant radiation therapy for STS of the thigh. These three patients had a tumor in posterior, adductor or anterior compartment of the thigh. In each case, three treatments plans were optimised in tomotherapy, without bloc, with directional bloc and complete bloc of controlateral limb, to adequately treat the planning target volume and spare organ at risk. For each patient, we compare the three modalities of tomotherapy or "classical" IMRT from a clinac with the 3D-CRT actually performed for the treatment. RESULTS: Tomotherapy provides improved PTV coverage and dose homogeneity. This benefit was comparable in the three tomotherapy plans. The average D95% for tomotherapy and 3D-CRT were 97.6% and 94.8% respectively and the standard deviation is, at least, divided by two with conformal and is always better than performed with a clinac. The volume of the surrounding soft tissues receiving at least full prescription and hot spots, as evaluated by D2%, were significantly reduced in tomotherapy. Nevertheless, the results concerning the skin, the femur and the gonads were dependent on the tumor site in the thigh and not always improved with tomotherapy dosimetric studies. CONCLUSIONS: For this preliminary study, tomotherapy can provide better coverage and dose uniformity in PTV and minimize the volume of surrounding muscular tissues receiving high doses. However, in this study, there is no benefit for others OAR (skin, femur and gonads) except in particular constraint (for instance for a precise sparing of cutaneous or bony area). Other dosimetric studies, followed by prospective evaluations with long-term follow-up are needed to determine whether tomotherapy can improve outcome for patients with STS of the thigh.

In vitro studies on the influence of carbomers on the availability and acceptability of estradiol gels.

The objective of the present study was to evaluate the pharmaceutical properties of estradiol (CAS 50-28-2) gels: pH, viscosity, texture, spreadability, evaporation of solvent and transcutaneous diffusion from carbomer-based formulations. This study was performed with the aim of measuring possible pharmaceutical differences as a function of the nature of the polymers used. The results obtained show a similarity of behaviour for the Estreva gels made with carbomers Carbopol 1342 (C 1342) and 1382 (C 1382). The reference gel, commercially available in France and made with the carbomer Carbopol 934 (C 934) is different in terms of its rheological criteria.