High-T C fully compensated ferrimagnetic semiconductors as spin-filter materials: the case of CrVXAl (X = Ti, Zr, Hf) Heusler compounds.

We extend our recent work on spin-filter materials (Galanakis et al 2013 Appl. Phys. Lett.103 142404) to the case of CrVXAl (X = Ti, Zr, Hf) compounds, for which, using ab initio electronic structure calculations, we show that p-d hybridization leads to the formation of a fully compensated ferrimagnetic semiconducting state with moderate exchange splitting. The magnetism is of covalent-type and the very strong antiferromagnetic Cr-V exchange interactions lead to extremely high Curie temperature, TC, values. Furthermore, all three compounds are thermodynamically and magnetically stable. The combination of very high TC values with a zero total net magnetization makes them promising materials for spintronics applications.

ErbB2, ErbB3 and ErbB4 expression in urothelial tumors of the upper urinary tract and their prognostic significance.

PURPOSE: ErbB family represents a promising therapeutic target in upper urinary tract urothelial carcinoma (UUTUC). Our study aimed to correlate ErbB2, ErbB3 and ErbB4 expression in UUTUC with other clinicopathological parameters as well as patient outcome. METHODS: ErbB2, ErbB3 and ErbB4 were immunohistochemically assessed in 99 consecutive UUTUC specimens. RESULTS: With a median follow-up of 52.5 months (range 1-127) 28 patients (28.3%) died 1-95 months after the first surgical treatment and the mean survival was 18.9-24.2 months. ErbB2, ErbB3 and ErbB4 expression was positive in 64.8, 19.5, and 20.8% of the tumors, respectively. Combined expression of all 3 receptors was found in 7.9% of the tumors, combined expression of 2 receptors in 14.5% and 48.7% expressed at least one ErbB receptor. No ErbB expression was found in 28.9% of the tumors. We found no significant correlation between ErbB2, ErbB3 and ErbB4 expression with tumor stage, grade, recurrence or cancer specific survival apart from the inverse relation between ErbB2 expression and time to recurrence (p=0.027). CONCLUSION: Of the 3 receptors evaluated, neither ErbB3 nor ErbB4 showed any prognostic significance in the UUTUC. ErbB2, however, was inversely associated with recurrence and needs further evaluation in well-designed, prospective, randomized trials.

A review of current hemostatic agents and tissue sealants used in laparoscopic partial nephrectomy.

Laparoscopic partial nephrectomy (LPN) is currently considered to be one of the most challenging procedures in minimally invasive urological surgery. With an increasing number of renal tumors being managed using LPN, there is now a further interest in the development of techniques and agents to reduce complications associated with the procedure. Hemostasis is of paramount importance during LPN, and hemostatic agents and tissue sealants are now being used commonly during LPN. Despite this, there is a dearth of prospective, randomized, human trials in current literature that compare the various agents. This review evaluates hemostatic agents and tissue sealants being used during LPN as an adjuvant to suturing in human studies.

Exchange interactions, spin waves, and Curie temperature in zincblende half-metallic sp-electron ferromagnets: the case of CaZ (Z = N, P, As, Sb).

Using first-principle calculations in conjunction with the frozen-magnon technique we have calculated the exchange interactions and spin-wave dispersions in the series of the zincblende half-metallic II-V (CaZ, Z = N, P, As, Sb) ferromagnets. The calculated exchange constants are used to estimate the Curie temperature within the random phase approximation. The large Stoner gap in these alloys gives rise to well-defined undamped spin waves throughout the Brillouin zone. Moreover we show that the spin-wave stiffness constants for the considered systems are among the largest available for local moment ferromagnets. The predicted Curie temperature of half-metallic CaN is noticeably higher than the room temperature with respect to the other compounds, and thus we propose CaN as a promising candidate for future applications in spintronic devices.

The use of radioisotopes for palliation of metastatic bone pain.

Bone pain associated with advanced prostate and other cancers is a frequent and significant complication. Pharmaceutical therapy of bone pain includes nonsteroidal analgesics and opiates. While external beam radiation therapy remains the mainstay of pain palliation of solitary lesions, bone-seeking radiopharmaceuticals have entered the armamentarium for the treatment of multiple osseous metastases. The 3 radioisotopes currently approved for treatment of pain (strontium-89/(89)Sr, samarium-153/(153)Sm and rhenium-186/(186)Re) are discussed in this review including the approved dose, method of administration and indications for use.

Spin-polarization and electronic properties of half-metallic Heusler alloys calculated from first principles.

Half-metallic Heusler alloys are amongst the most promising materials for future magneto-electronic applications. We review some recent results on the electronic properties of these compounds. The origin of the gap in these half-metallic alloys and its connection to the magnetic properties are well understood. Changing the lattice parameter slightly shifts the Fermi level. Spin-orbit coupling induces states within the gap but the alloys keep a very high degree of spin polarization at the Fermi level. Small degrees of doping and disorder as well as defects with low formation energy have little effect on the properties of the gap, while temperature effects can lead to a quick loss of half-metallicity. Finally, we discuss two special issues: the case of quaternary Heusler alloys and the half-metallic ferrimagnets.

A review of the electronic and magnetic properties of tetrahedrally bonded half-metallic ferromagnets.

The emergence of the field of spintronics has brought half-metallic ferromagnets to the centre of scientific research. A lot of interest was focused on newly created transition-metal pnictides (such as CrAs) and chalcogenides (such as CrTe) in the metastable zinc-blende lattice structure. These compounds were found to have the advantage of high Curie temperatures in addition to their structural similarity to semiconductors. Significant theoretical activity has been devoted to the study of the electronic and magnetic properties of these compounds in an effort to achieve a better control of their experimental behaviour in realistic applications. This paper is devoted to an overview of the studies of these compounds, with emphasis on theoretical results, covering their bulk properties (electronic structure, magnetism, stability of the zinc-blende phase, stability of ferromagnetism) as well as low-dimensional structures (surfaces, interfaces, nanodots and transition-metal delta-doped semiconductors) and phenomena that can possibly destroy the half-metallic property, like structural distortions or defects.

Half-metallic alloys: electronic structure, magnetism and spin polarization.

Using the state-of-the-art screened Korringa-Kohn-Rostoker Green function method we study the electronic and magnetic properties of NiMnSb and similar Heusler alloys. We show that all these compounds are half-metals, e.g. the minority-spin band is semiconducting and the Fermi level falls within this gap resulting in 100% spin polarization at the Fermi level. The total spin moment M(t) shows the so-called Slater-Pauling behaviour and scales with the total valence charge Z(t) following the rule M(t) = Z(t) - 18 for half and M(t) = Z(t) - 24 for full Heusler alloys. These rules are connected to the origin of the gap. Finally we show that the inclusion of the spin-orbit interaction in our calculations kills the half-metallic gap but the spin-polarization at the Fermi level can be still very high, approximately 99% for NiMnSb, but much lower for a half-metallic compound like zinc-blende MnBi (77%).

Stability of ferromagnetism in the half-metallic pnictides and similar compounds: a first-principles study.

Based on first-principles electron structure calculations and employing the frozen-magnon approximation, we study the exchange interactions in a series of transition-metal binary alloys crystallizing in the zinc-blende structure and calculate the Curie temperature within both the mean-field approximation and random-phase approximation. We study two Cr compounds, CrAs and CrSe, and four Mn compounds, MnSi, MnGe, MnAs and MnC. MnC, MnSi and MnGe are isovalent to CrAs and MnAs is isoelectronic to CrSe. Ferromagnetism is particular stable for CrAs, MnSi and MnGe: all three compounds show Curie temperatures around 1000 K. On the other hand, CrSe and MnAs show a tendency to antiferromagnetism when compressing the lattice. In MnC the half-metallic gap is located in the majority-spin channel, in contrast to the other five compounds. The large half-metallic gaps, very high Curie temperatures, the stability of the ferromagnetism with respect to the variation of the lattice parameter and a coherent growth on semiconductors make MnSi and CrAs the most promising candidates for use in spintronics devices.

Functional outcome of burst fractures of the thoracolumbar spine managed non-operatively, with early ambulation, evaluated using the load sharing classification.

The purpose of this prospective study was to assess the functional outcome of conservative treatment with early ambulation of thoracolumbar burst fractures, using the Load Sharing classification. From 1997 to 2001, 60 consecutive patients with single-level thoracolumbar spinal injury, with no neurological impairment, were classified according to the Load Sharing scoring and were managed non-operatively. A custom-made thoracolumbosacral orthosis was worn by all patients for six months, and early ambulation was recommended. Several radiological parameters were evaluated; the Denis Pain and Work Scale was used to assess the clinical outcome. The average follow-up period was 42 months (range, 24 to 55 months). During this period the spinal canal occupation was significantly reduced. Other radiological parameters, such as Cobb's angle and anterior vertebral body compression, showed loss of fracture reduction, which was not statistically significant. However, the functional outcome was satisfactory in 55 of 60 patients with no complications recorded on completion of treatment. Load Sharing scoring is a reliable and easy-to-use classification for the conservative treatment and prognosis of thoracolumbar spinal fractures. Because of the three characteristics of the fracture site this classification can also predict the structural results of spinal injury, such as posttraumatic kyphosis, as well as the functional outcome in conservatively treated patients.

Placement of the distal locking screws of the femoral intramedullary nail without radiation.

An H-shaped device was invented to facilitate placement of the distal interlocking screws during closed femoral nailing. Eleven sound cadaveric femurs were experimentally nailed before the application of the device in 15 patients with a femoral shaft fracture. In all experimental cases the insertion of the distal screws proved to be easy. In 11 of 15 patients with a femoral fracture, distal locking was achieved using the H-device. These primary results should stimulate further clinical application of the device.

Comparative biomechanics of the sliding screw-plate and the Bousquet nail-plate.

Four stable and 12 unstable trochanteric fractures were produced in human cadavers and fixed with either a sliding screw-plate or the Bousquet nail-plate. Axial cyclic loading showed that both implants were satisfactory for stable fractures. The sliding screw-plate withstood increased loads and the system failed at a later cycle in unstable fractures. Central placement of both the sliding screw or nail enhances stability, especially against torsional forces.

Dislocation of the shoulder and ipsilateral fracture of the humeral shaft: case reports and literature review.

Shoulder dislocation associated with ipsilateral humeral shaft fracture is an uncommon combination. Two cases treated, one by open and the other by closed methods, are presented. The mechanism of this complex injury is detailed and the treatment modalities are discussed. The relevant literature is reviewed.

Correct placement of the screw or nail in trochanteric fractures. Effect of the initial placement in the migration.

This is a prospective study of 106 patients with 37 stable and 69 unstable trochanteric fractures treated with 2 different implants: a sliding screw-plate and a triflanged nail-plate. The fractures were classified according to Jensen's modification of Evans classification. The parameter migration was compared between the 2 implants and for the various areas of placement of the screw or nail within the femoral head. For stable fractures, the migration observed was independent of the area of implant placement or the type of implant used. For unstable fractures, central placement of the sliding screw resulted in a decreased mean value of migration. When the nail was used, the mean values of migration observed were independent of the areas of placement within the femoral head. In cases of central placement, the sliding screw appeared to be superior to the triflanged nail.