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Abstract  The temperature and pressure characteristics of a noncentrosymmetric crystal modification of NaNbO3 were studied by Raman spectroscopy. A transition towards the bulk-like structure of NaNbO3 occurs in the temperature range from 280 to 360 °C. High-pressure Raman spectroscopy revealed successive pressure-induced phase transitions at around 2, 6.5 and 10 GPa. Raman scattering profiles recorded above 7 GPa correspond to those reported for the bulk. The temperature-induced spectral changes were completely reversible between −150 and 450 °C. Those induced by pressure were almost reversible from ambient pressure up to 15.9 GPa. Piezoresponse force microscopy demonstrated the occurrence of piezoelectric activity for submicron NaNbO3 crystals with particle size ranging from 200 to 400 nm. The noncentrosymmetric crystallographic structure plays a critical role for the enhancement of piezoelectricity. [ABSTRACT FROM AUTHOR]

The electrical conductivity of donor-doped BaTiO 3 thermistor ceramics with excessive BaO revealing a reduction-persistent PTCR effect has been carefully examined depending on materials' composition and oxygen partial pressure at moderate temperatures between 973 and 1273 K. This thermal regime represents the range which is relevant for the realization of insulating grain boundaries in these electrically inhomogeneous ceramic materials through reoxidation. Based on the experimental results strong evidence for a general correlation between the PTCR characteristics, DC-conductivity and the herewith associated defect chemistry significant to thermistor applications is presented for the system (Ba, La) m TiO 3 , where m designates the BaO-excess (m≥ 1). Nominal compositions with a relatively low (Ba + La)/Ti ratio m only show a rather poor PTCR effect and an overall donor-type response in conductivity can be observed at all levels of oxygen partial pressure considered in the present study. With increasing (Ba + La)/Ti ratio m the nonlinear resistivity jump with increasing temperature strongly improves and the acceptor-type behaviour seems to dominate the total conductivity at partial pressures of oxygen above approximately 10 -6 MPa. This result for compositions with high BaO-excess can be understood by the local formation of point defect associates in the grain boundary regions that consist of both acceptor-type titanium vacancies and donor-type oxygen vacancies. Their origin is attributed to the preferential local incorporation of excessive BaO into the BaTiO 3 lattice at the intergranular interfaces.

Objective: Mediterranean diet is associated with decreased levels of inflammatory markers and metabolic risk factors in epidemiologic studies and recent trials on patients with metabolic syndrome. Given the recent improvements in medical treatments, it is unclear if such beneficial effects are also present in patients with coronary artery disease (CAD). We therefore investigated the effect of Mediterranean diet on markers of inflammation and metabolic risk factors in patients with treated CAD., Design: Randomized, controlled trial., Subjects: A total of 101 patients (59.4+/-8.6 years, 23% female) with established and treated CAD (80% statins)., Interventions: Participants were assigned to a Mediterranean diet group (MG; n=48) with a 1-year program of 100 h of education, or to a written advice-only group (AG; n=53). Before and after intervention, we measured serum high-sensitivity C-reactive protein (hs-CRP), fibrinogen, fasting insulin, homocysteine, serum lipids and plasma fatty acids., Results: The Mediterranean diet program increased the intakes of fish, fruits/vegetables and moderately of canola/olive oil and increased plasma concentrations of long-chain n-3 polyunsaturated fatty acids in the MG. Median hs-CRP and mean fibrinogen, homocysteine, fasting insulin, triglycerides and serum cholesterols remained unchanged in both groups., Conclusions: Adoption of a Mediterranean diet by patients with medically treated CAD has no effect on markers of inflammation and metabolic risk factors., Sponsorship: Alfried Krupp Foundation, Essen, Germany.

Background: Although redefinition for acute myocardial infarction (AMI) has been proposed few years ago, to date it has not been universally adopted by many institutions. The purpose of this study is to evaluate the diagnostic, prognostic and economical impact of the new diagnostic criteria for AMI., Methods: Patients consecutively admitted to the emergency department with suspected acute coronary syndromes were enrolled in this study. Troponin T (cTnT) was measured in samples collected for routine CK-MB analyses and results were not available to physicians. Patients without AMI by traditional criteria and cTnT > or = 0.035 ng/mL were coded as redefined AMI. Clinical outcomes were hospital death, major cardiac events and revascularization procedures. In-hospital management and reimbursement rates were also analyzed., Results: Among 363 patients, 59 (16%) patients had AMI by conventional criteria, whereas additional 75 (21%) had redefined AMI, an increase of 127% in the incidence. Patients with redefined AMI were significantly older, more frequently male, with atypical chest pain and more risk factors. In multivariate analysis, redefined AMI was associated with 3.1 fold higher hospital death (95% CI: 0.6-14) and a 5.6 fold more cardiac events (95% CI: 2.1-15) compared to those without AMI. From hospital perspective, based on DRGs payment system, adoption of AMI redefinition would increase 12% the reimbursement rate [3552 Int dollars per 100 patients evaluated]., Conclusions: The redefined criteria result in a substantial increase in AMI cases, and allow identification of high-risk patients. Efforts should be made to reinforce the adoption of AMI redefinition, which may result in more qualified and efficient management of ACS.

NaNbO(3) powders with various particle sizes (ranging from 30 nm to several microns) and well-controlled stoichiometry were obtained through microemulsion-mediated synthesis. The effect of particle size on the phase transformation of the prepared NaNbO(3) powders was studied using X-ray powder diffraction, Raman spectroscopy, and nuclear site group analysis based on these spectroscopic data. Coarsened particles exhibit an orthorhombic Pbcm (D(2h)(11), no. 57) structure corresponding to the bulk structure, as observed for single crystals or powders prepared by conventional solid-state reaction. The crystal symmetry of submicron powders was refined with the space group Pmc2(1) (C(2v)(2), no. 26). The reduced perovskite cell volumes of these submicron powders were most expanded compared to all the other structures. Fine particles with a diameter of less than 70 nm as measured from SEM observations showed an orthorhombic Pmma (D(2h)(5), no. 51) crystal symmetry. The perovskite formula cell of this structure was pseudocubic and was the most compact one. A possible mechanism of the phase transformation is suggested.

Although several advances have been made in the management of acute coronary syndromes, the adoption of such measures in clinical practice has been suboptimal. The implementation of critical pathways has been suggested as a strategy to improve clinical effectiveness, although its effect is still to be demonstrated. The objective was to evaluate the impact of a critical pathway on the process of care of patients admitted with acute coronary syndromes in a teaching hospital. In a prospective cohort study, patients 30 years or older admitted to the emergency department with suspected acute coronary syndromes were evaluated. Primary outcomes were major cardiovascular events, percutaneous coronary intervention, and in-hospital mortality during 1 semester before and 4 semesters after implementation of the pathway. Multivariate logistic regression analysis was used to adjust for differences between the periods studied and to identify predictors of poor prognosis. Of the 1003 patients evaluated, 150 (15%) had myocardial infarction, and 240 (24%) had unstable angina. There was no difference in clinical characteristics and risk assessment in the periods evaluated. Overall, the quality of care improved after the pathway, with a significant decrease in complication and mortality rates in the last 2 years. In multivariate analysis, patients admitted in the last semester showed fewer major cardiovascular events (odds ratio = 0.74; P = 0.02) and more percutaneous coronary intervention (odds ratio = 1.3; P = 0.03). The implementation of a critical pathway may have a positive impact on the quality of care of patients with acute coronary syndromes. Further studies are needed to evaluate better this and other initiatives aimed at maximizing clinical effectiveness.

This study aimed to evaluate the feasibility and reliability of bioelectrical impedance spectroscopy in young children suffering of acute hydrational disorders. Whole body and segmental measurements were carried out in a group of 42 of children aged 4 to 147 months, using a BIS analyzer (Xitron 4000B). This phase of the study involved several hundred of BIS measurement, which showed the feasibility of using this technique in young children. Using the sweep mode and the modeling software provided for the manufacturer of the instrument, the resistance of the extracellular (RECW) and intracellular (RICW) compartment was calculated. Correlation coefficient (r) and technical error of measurement (TEM) were obtained from paired BIS measurements. RECW showed to be highly reproducible (r = 0.99), with a relatively low TEM (from 1 to 3.5%), across all segments. The reliability was markedly lower respect to RICW, which shows the potential application of BIS technique even in critically ill young child populations.