Prospective study of nosocomial infections in a medical ICU. A proposal for the generalized use of the National Nosocomial Infection Surveillance System rates

Symptoms due to renal lesions often disappear and smolder by successful treatment during the first episode of Wegener's granulomatosis (WG). It is indispensable to recognize an increase in disease activity and provide adequate treatment to inhibit the progression of renal dysfunction as well as regulate disease activity in patients with WG. We gave attention to red blood cells in urinary sediment (U-RBC), a criterion in the diagnosis of WG, to more exactly determine the degree of renal activity. Comparison of level of U-RBC with other laboratory data and renal histology was performed in the clinical course of six cases. The level of U-RBC altered reversibly during the period studied and correlated with the C-reactive protein level and erythrocyte sedimentation rate which reflect disease activity in cases with microhematuria before treatment. When U-RBC disappeared within eight weeks after treatment, glomerular histological change remained small. The reported cases revealed that the alteration in U-RBC was more sensitive and more specific for renal involvement than the other disease markers. In conclusion, the level of U-RBC reflects the degree of renal activity in WG. We propose that the quantitation of U-RBC is extremely useful in following patients with WG.     

Mechanism of Low‐Temperature Protonic Conductivity in Bulk,High‐Density,Nanometric Titanium Oxide

Uncovering the mechanism of low‐temperature protonic conduction in highly dense nanostructured metal oxides opens the possibility to exploit the application of simple ceramic electrolytes in proton exchange fuel cells, overcoming the drawbacks related to the use of polymeric membranes. High proton conducting, highly dense (relative density 94 vol%) TiO₂ samples are prepared by a fast pressure‐assisted sintering method, which allows leaving behind an interconnected network of open nanoporosity. Solid‐state ¹H NMR is used to characterize the presence of strongly associated water confined in the nanopores and hydroxyl moieties bonded to the pores walls, providing a model to explain the unusually high protonic conductivity. At the lowest temperatures (T < 55 °C) protons hop between confined water molecules, according to a Grotthuss mechanism. The resulting conductivity values are however much higher than those of liquid water, indicating a significant increase in the charge carriers concentration. At higher temperatures (up to 450 °C) unexpected proton conduction is still present, thanks to the persistence of hydroxyl groups, derived from water chemisorption, which still produce protons by ionization. The phenomenon is strongly dependent on grain size, and not explicable by simple geometric brick‐layer models, suggesting that the enhanced ionization could rely on space charge region effects.     

Transient motor aphasia at high altitude

Several focal forms of infection by Salmonella no typhi, as the endocarditis, are very rare and the coexistence of splenic abscess is even more rare. We present a case in which the simultaneous presence of both infections was observed and we review the literature with special emphasis in the therapeutical aspects.     

Thermal Stability of Combustion-Synthesized Metastable Solid Solutions of Zirconia and Transition Metals

The thermal stability of combustion-synthesized metastable solid solutions of zirconia and transition metals was investigated. When heated to 800°C or higher, these solutions decomposed to a mixture of monoclinic ZrO₂ and the transition metal oxide. Both Fe- and Co-doped solid solutions behaved similarly with respect to decomposition. The extent of decomposition was highly dependent on the temperature. In situ X-ray diffraction studies provided details on the decomposition process.     

Severe and complicated malaria. Report of six cases

The major obstacle for successful xenotransplantation of islets to large animals and human diabetics is the host rejection. To address the rejection problem, we studied the efficacy of UV-B irradiation, cryopreservation and immunosuppression on the in vivo functional time and immunogenicity of adult porcine islets (PI) in outbred CD1 mice. Exposure of PI to UV-B irradiation between 300-1800J/M2 did not affect the cellular viability as assessed by fluorescein diacetate or their daily insulin secretion in vitro. Fresh PI normalized the blood glucose (BG) of diabetic CD1 mice for 3.1+/-0.6 (n = 8, mean+/-SEM) days. Islets treated with 600J/M2 UV-B irradiation or cryopreservation had similar graft functional times to fresh islets upon transplantation in diabetic CD1 mice. Immunosuppression with cyclosporin A (CsA), antilymphocyte serum (ALS) and FK506 prolonged the functional time of fresh pig islets to 7.9+/-0.9 (n = 9), 6.2+/-1.3 (n = 5) and 24.2+/-10.4 (n = 12) days, respectively. However, additional pretransplant treatment with either UV-B irradiation or cryopreservation did not further increase the functional time of pig islets in mice immunosuppressed with CsA. Furthermore, there was no apparent difference in the frequency of appearance of cytotoxic antibodies and antibody titers in the recipients of UV-B irradiated or cryopreserved pig islet compared with non-treated islets. The UV-B irradiation and cryopreservation of PI before transplantation with the present protocols did not appear to have significant effect on the islet immunogenicity when assessed by in vivo survival duration and anti-donor antibody titer production.     

Nickel/Yttria-Stabilized Zirconia Cermets from Combustion Synthesis: Effect of Process Parameters on Product Microstructure

The synthesis of a nickel/yttria-stabilized zirconia (Ni/YSZ) cermet with tailored microstructural characteristics has much interest for many solid-state electrochemical applications. These materials are generally obtained through a route based on the reduction, via hydrogen gas, of poorly sintered mixtures of YSZ with nickel oxide. The present paper proposes an alternative route based on a thermite reaction performed in a combustion regime. Such an approach indicates the application of combustion synthesis or a self-propagating high-temperature synthesis (SHS) technique. The more-interesting features of this route include the absence of any external source of energy during the reaction, the possibility to synthesize a porous cermet in a single step, its sintering, and the doping of the ceramic component with yttria. The synthesis of Ni/YSZ cermets through this route is analyzed in some detail, and this analysis shows the influence of the process parameters on the phase composition and microstructure of the products.     

Role of mechanical activation in SHS synthesis of TiC

The effect of the mechanical activation of the reactants on the self-propagating high-temperature synthesis (SHS) of titanium carbide was investigated. The SHS experiments were performed on two compositions, Ti₅₀C₅₀ and Ti₇₀C₃₀, which define the homogeneity range of the TiC equilibrium carbide. Milling times were progressively increased up to the time at which a combustion-like process ignites spontaneously under milling. The combustion peak temperature, wave velocity, and ignition temperature were markedly influenced by the degree of mechanical activation of the reactants. In particular the ignition temperature was observed to decrease from a temperature corresponding to the melting point of Ti to 500°C. The apparent activation energy for propagation of the combustion wave was also determined (～100 kJ·mol^?1) and was found to be independent of both the degree of mechanical activation and the composition of the starting mixture.     

Synthesis and characterization of pure and doped (Na, Ca, Sr) nanograined LaMnO3 magnetoresistive ceramics

Pure and Na, Ca, and Sr doped lanthanum manganites (LaMnO3, La0.85Na0.15MnO3, La0.7Ca0.3 MnO3, La0.7Sr0.3MnO3) were prepared in form of bulk nano-structured materials through a two-step process. Nanometric powders were synthesized by the Pechini method and subsequently densified by Spark Plasma Sintering at 1273 K for 5 minutes under a pressure of 140 MPa. The method allowed the preparation of single phase manganites with a theoretical density above 98% together with a very limited growth of the grain size. Grain sizes below 70 nm were obtained for all materials except La0.85Na0.15MnO3 which showed a much larger grain size. Curie temperatures (Tc) and magnetoresistivity properties of the samples were measured by a Superconducting Quantum Interference Device (SQUID). The decrease in the resistivity below Tc occurred in a much wider range of temperature compared to ceramics having micron-size grains.     

Zirconia-Based Metastable Solid Solutions through Self-Propagating High-Temperature Synthesis: Synthesis, Characterization, and Mechanistic Investigations

Cubic Zr_{1− x} Me _x O _y (Me = Fe, Co, Ni, Cu) metastable solid solutions with metal content significantly higher than equilibrium levels have been synthesized by the self-propagating high-temperature synthesis method based on a thermite reaction between metallic zirconium and the transition-metal oxides CoO, Fe₂O₃, CuO, and NiO. Through in situ XRD analysis, it was determined that when heated to 1100°C, the cubic solid solution transformed to the tetragonal phase with the concomitant formation of iron oxide. When cooled to lower temperatures, the tetragonal phase transformed to the monoclinic phase at or below 500°C. Results of auxiliary experiments strongly suggest that the formation of the solid solution takes place behind the combustion front by a reaction between zirconia and the metal.