Crystallographic and magnetic properties of HfFe6Ge6-type REFe6Sn4Ge2 compounds (RE = Y, Gd–Er)

The REFe₆Sn₄Ge₂ (RE = Y, Gd–Er) compounds have been synthesized and studied by powder X-ray diffraction and magnetisation measurements. These compounds crystallize in the hexagonal HfFe₆Ge₆ structure although the parent ternary compounds REFe₆X₆ (X = Ge, Sn) display more complicated orthorhombic crystal structure. This evolution is discussed and interpreted on the basis of the relaxation of some RE–X contacts in the quaternary compounds. The iron sublattice order antiferromagnetically above room temperature (554 ≤ T_N ≤ 560 K) while the paramagnetic RE compounds display a second transition at low temperature (7.3 ≤ T_t ≤ 42.7 K). The magnetisation versus field curves display a metamagnetic behaviour at 4.2 K. The corresponding value of the magnetisation suggests a non-collinear ordering of the RE sublattice.     

Should right-sided fibroelastomas be operated upon?

There is general agreement that left-sided elastomas must be removed to avoid systemic complications. Right-sided localization is less risky and surgical treatment is not agreed upon. We report a case of surgical resected fibroelastoma of the tricuspid valve and discuss the indications to surgery by reviewing the literature on the few reported cases. We feel that, if surgery is timely, the tumor can be resected, thus preserving the native valve. This provides an opportunity to prevent possible right-sided complications due to increasing tumor size and embolization.     

Competitive inhibition of swine kidney copper amine oxidase by drugs: amiloride, clonidine, and gabexate mesylate

Carotid artery injuries from seat belt shoulder straps have been reported involving primarily the internal carotid artery. This paper describes a case of common carotid artery disruption and tracheal transection after a shoulder strap seat belt injury. A successful method for management of this rare injury is presented. Repair involved autogenous arterial replacement in a contaminated field using an interposition graft of superficial femoral artery.     

Advanced HIV infection treated with zidovudine monotherapy: lifetime values of absolute cost-effectiveness as a pharmacoeconomic reference for future studies evaluating antiretroviral combination treatments. The Osservatorio SIFO sui Farmaci

OBJECTIVE: This study was undertaken to evaluate the cost and the effectiveness of zidovudine monotherapy in patients with advanced HIV infection and to derive preliminary data on the cost-effectiveness of the triple treatment with saquinavir plus zalcitabine plus zidovudine compared with zidovudine alone. DESIGN: We used a combined method of survival analysis utilizing both the quality-adjusted time without symptoms or toxicity (Q-TWIST) method and the Gompertz approach. This combined method was applied to assess the absolute cost-effectiveness and cost-utility ratios of zidovudine monotherapy and to perform a preliminary incremental cost-effectiveness comparison of saquinavir plus zalcitabine plus zidovudine versus zidovudine alone. The clinical material used in our study was derived from two reports on the treatment of advanced HIV infection. Data of lifetime costs of HIV infection were obtained from published information. RESULTS: In patients with advanced HIV infection treated with zidovudine monotherapy, lifetime survival was 252.1 discounted person-years per 100 patients. Using an average lifetime cost of $93,000 (discounted) per individual, the absolute ratio of cost-effectiveness for zidovudine monotherapy was $36,980 per life-year, while the absolute cost-utility ratio was $47,112 per quality-adjusted life-year. In the comparative analysis of saquinavir plus zalcitabine plus zidovudine versus zidovudine alone, our calculations showed that the administration of the triple treatment can have an "average" cost-effectiveness, provided that mean lifetime survival per patient (discounted) is improved to at least 3.68 years (with an average survival gain of at least 14 mo per patient). CONCLUSIONS: The values of absolute cost-effectiveness and cost-utility ratios for zidovudine monotherapy are a useful reference point for further pharmacoeconomic studies in the area of antiretroviral drugs.     

Partial biochemical characterization of nitric oxide synthase in the caudal spinal cord of the teleost Oreochromis niloticus

This article presents two cases in which an intraarticular fracture of the ulnar head occurred in association with a dorsal dislocation of the distal radioulnar joint. After open reduction and internal fixation of the osteochondral fragment, final outcomes were excellent.     

LuMnGe2, un nouveau type structural apparente a ceux de TiMn(Fe)Si2, ZrMnSi2 et ZrFeSi2; ScMnGe2, un nouvel isotype de TiMn(Fe)Si2

LuMnGe₂ has been studied by single - crystal X-ray diffraction analysis. The structure is of a new type with space group Cmmm and Z = 12: a = 5.466(2), b = 18.519(7), $\text{c}\text{= 8.173(3)}\text{A}\text{?}$, D_x = 9.03 Mg m^?3, μ(AgKα) = 31 mm^?1, F(000) = 1919, R = 0.030 for 593 independant reflexions (R_w = 0.034). The LuMnGe₂ structure type had been predicted and completes a large structural family TT′Si(Ge)₂ where T = Nb, Ti, Zr, Hf, Sc, Lu and T′ = Cr, Mn, Re, Fe, Co, where ScMnGe₂ is another new member, isostructural with TiMn(Fe)Si₂     

Issues to consider, existing tools and constraints in biofuels sustainability assessments

Biofuels world production has increased sharply in recent years. Oil reserves depletion, the oil high price and the confidence in biofuels “carbon neutrality” are the main causes of this phenomenon. However, claims related to the negative consequences of biofuel programs are frequent; mainly those related to the biofuels/food competition and sustainability. This paper aims to contribute for the development of a framework for sustainability indicators as a tool for performance assessment. The most used indicators to measure the biofuels sustainability are: Life Cycle Energy Balance (LCEB), quantity of fossil energy substituted per hectare, co-product energy allocation, life cycle carbon balance and changes in soil utilization. On the other hand, existing assessment tools, such as Life Cycle Assessment (LCA) and Integrated Environmental Assessment (IEA), are compared emphasizing their advantages and disadvantages. Main constraints related to the studied frontiers, as well as the lack of reliable data and their effects are also discussed. Discussions are held on the basis of real life cycle studies carried out by the authors about palm oil biodiesel and different alternatives for the stillage treatment and disposal. Finally, suggestions and recommendations are made to improve existing methodologies for biofuels sustainability evaluation, all this from a south perspective.     

BEM formulation for von Kármán plates

This work deals with nonlinear geometric plates in the context of von Kármán's theory. The formulation is written such that only the boundary in-plane displacement and deflection integral equations for boundary collocations are required. At internal points, only out-of-plane rotation, curvature and in-plane internal force representations are used. Thus, only integral representations of these values are derived. The nonlinear system of equations is derived by approximating all densities in the domain integrals as single values, which therefore reduces the computational effort needed to evaluate the domain value influences. Hyper-singular equations are avoided by approximating the domain values using only internal nodes. The solution is obtained using a Newton scheme for which a consistent tangent operator was derived.     

Activation of microglial cells by PrP and beta-amyloid fragments raises intracellular calcium through L-type voltage sensitive calcium channels

The prion protein (PrP) and the amyloid beta (Abeta) precursor protein (APP) are two normal proteins constitutively synthesised in human brain. An altered form of PrP accumulates in Creutzfeldt-Jakob disease, while Abeta is involved in the pathogenesis of Alzheimer's disease. Synthetic fragments of both proteins, PrP106-126 and beta25-35 (beta25-35), have been demonstrated to induce neurodegeneration and microglia activation. This study was undertaken to compare PrP106-126 and beta25-35 capability of activating human resting microglial cells. Our results show that both peptides are able to induce microglial activation and to elicit an increase in [Ca2+]i levels in cells loaded with calcium-green 1. Inhibitors of L-type voltage-sensitive calcium channels (verapamil, nifedipine and diltiazem) prevented the increase in [Ca2+]i concentration as observed after treatment with PrP106-126 and beta25-35, thus indicating a transmembrane calcium influx through these channels. In addition, verapamil abolished the proliferative effect of both PrP106-126 and beta25-35.