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Largely Cu-doped LaCo1-xCuxO3 perovskites for TWC: Toward new PGM-free catalysts

Doping of LaCoO3 with copper to add reduction functionality in addition to the known oxidation properties has been investigated, aiming at three-way catalysis (TWC) applications. Nanoscale perovskites with nominal composition LaCo1-xCuxO3, (x=0, 0.1, 0.3, and 0.5) have been synthesized by means of the citrate method. A stable perovskitic phase with rhombohedral geometry up to an unprecedented x=0.5 has been obtained and characterized by BET, X-ray diffraction (XRD), Temperature Programmed Reduction (TPR), X-ray Photoelectron Spectroscopy (XPS), and Scanning Electron Microscopy (SEM). The crystallite size decreases with increasing the copper amount and also the morphology differs; moreover the surface reactivity with respect to atmospheric moisture and carbon dioxide is more evident in the sample with x=0.5. Reactivity has been measured in simple NO+CO and CO+O2 model reactions, as well as with complex mixtures approaching automotive exhaust composition, at both stoichiometric and O2 limiting conditions. The catalysts have been characterized after reaction as well. The perovskite with the highest Cu amount, LaCo0.5Cu0.5O3, exhibits an interesting compromise of oxidation and NO reduction functionality at interesting, low temperatures with very short contact time (GHSV=1,000,000h-1). Still, activity for NO reduction in real mixtures requires substoichiometric O2

Pheochromocytoma presenting as an acute coronary syndrome complicated by acute heart failure: The challenge of a great mimic

Pheochromocytoma is a rare neuroendocrine tumor with a highly variable clinical presentation. The serious and potentially lethal cardiovascular complications of these tumors are related to the effects of secreted catecholamines. We describe a case of a 50-year-old woman urgently admitted to our hospital because of symptoms and clinical and instrumental findings consistent with an acute coronary syndrome complicated by acute heart failure. Urgent coronary angiography showed normal coronary arteries. During her hospital stay, the recurrence of episodes characterized by a sudden increase in blood pressure, cold sweating, and nausea allowed us to hypothesize a pheochromocytoma. The diagnosis was confirmed by elevated levels of urinary catecholamines and by the finding of a left adrenal mass on magnetic resonance imaging. The patient underwent left adrenalectomy. Therefore, the initial diagnosis was critically reappraised and reviewed as a cardiac manifestation of a pheochromocytoma during catecholaminergic crisis

Caspase-3 Causes the Formation ofHuman-Tau-Derived Toxic Fragments During Neuronal Apoptosis

Truncated tau proteins are a hallmark of human Alzheimer’s disease (AD).The cleaved state of tau influences its physiological ability to bind microtubules, to assume ADrelated pathological conformations, to aggregate and assemble into filaments and to induce neuronal death .A transgenic rat model overexpressing truncated human tau has been shown to cause in vivo neurofibrillary tangles, demonstrating that cleaved forms of tau are sufficient to produce AD-like neurofibrillary degeneration by inducing oxidative stress. Previously, we have shown that adenovirus- mediated overexpression of 25-230 human tau fragment evokes a potent neurotoxic effect in primary neuronal cultures by sustained stimulation of NMDA receptor (Amadoro et al.,2006). In order to assess whether the 25-230 fragment is actually produced during apoptosis, we attempted to ascertain its presence using a site-directed, caspase 3- cleaved antibody (Rohn et al., 2002) against amino-terminal consensus cleavage site D25 of tau protein (QGGYTMHQDQ). We provide biochemical evidence that N-tau 25-230 fragments, consistent with the sizes produced by caspase -3 and calpain cleavage of different tau isoforms, are generated in staurosporine-treated differentiated human SY5Y. These findings support the notion that activation of apoptotic mechanism(s) may be directly involved in AD pathogenesis, possibly also via generation of tau fragments, indicating that inhibition of caspase-mediated cleavage of this protein(s) may be protective in vivo

Preliminary study on Norovirus, hepatitis A virus, Escherichia coli and their potential seasonality in shellfish from different growing and harvesting areas in Sardinia region

Edible lamellibranch molluscs can be involved in foodborne disease and infections of varying severity. They are filter feeding animals able to retain and concentrate in their organism bacteria, parasites, viruses and biotoxins marine algae present in their external environment. Major shellfish harvesting and relaying areas from different areas in Sardinia region were defined and studied by analysing different physicochemical parameters in the water and the levels of Escherichia coli (E. coli), Norovirus (NoVs) genogroup I (NoVGI), NoVs genogroup II (NoVGII) and hepatitis A virus (HAV) in the shellfish harvested and farmed from 2009 to 2011. During that period the identification of the viral agents was carried out by one step real-time reverse transcriptase-polymerase chain reaction and Escherichia coli according to ISO TS 16649- 3:2005 standard method. A total of 1266 shellfish samples were tested for NoVGI, NoVGII, HAV and faecal indicators. Norovirus contamination was found in 337 samples (26.6%); only one sample of mussels was positive for HAV (0.08%); while E. coli prevalence was 3.8% in shellfish. The probability of observing shellfish samples positive for NoVs, HAV and E. coli presence was associated with harvesting, growing and relaying areas, period of sampling, environmental parameters, animal species (P<0.05). Although the higher prevalence rate of human enteropathogenic viruses was found in the winter period, we did not observe a significant relationship between the effect of seawater temperature (seasonality) and NoVs presence all over the study period; in fact, according to statistical analysis, the presence of human enteric viruses does not appear to be related to water temperature

Cu@LaNiO3 based nanocomposites in TWC applications

Several nanocomposites of the type CuO/LaNiO3 (Cu@LaNiO3) have been developed for application as noble metal free catalysts in TWC. The nanocomposites have been obtained by depositing copper oxide on lanthanum nickelate. The supporting perovskite has been prepared by means of the citrate route; copper, in contrast, was deposited by means of an innovative procedure: ammonia driven deposition precipitation method (ADP) optimized for deposition on perovskites. The nanocomposites have been developed based on the catalytic activity of LaNiO3 in oxidation and reforming reactions and of copper in reduction reactions. Nanocomposition is thus used to deposit a highly dispersed active specie (CuO) on an active support (LaNiO3) with the aim of building catalytic functionality. The obtained nanocomposites have been characterized by means of XRD, XPS, SEM, TPR, BET, EDX, and ICP and the obtained results are correlated to the amount of copper deposited and to the reactivity. The reactivity was studied first in two model reactions, CO oxidation and CO assisted NO reduction, in order to investigate the role played by the different species. Moreover, the reactivity under real conditions, i.e. with a complex mixture reflecting the actual automotive exhaust composition, was considered to evaluate the real applicability. Finally, high-temperature deactivation was investigated. XPS reveals that the deposition of copper oxide affects the surface composition of the nanocomposites; the XRD, SEM, and TPR results confirm that CuO is deposited on the LaNiO3 surface and no diffusion below surface is observed. CuO species are deposited both as highly dispersed phase and as bigger particles; the relative amount of these phases depends on the total amount of copper deposited. The reactivity in the CO oxidation reaction is not significantly affected by the copper deposition. In contrast the reactivity in NO reduction is strongly enhanced by the presence of highly dispersed copper species. Activity tests with mixture reflecting actual automotive exhaust, reveal an enhancement in CO oxidation, but no NO decomposition at stoichiometric conditions. Complete NO reduction is achieved at rich conditions; also, hydrocarbons reforming reactions typically occurring at substoichiometric O2, with CO and H2 production, are less supported, preserving the activity in NO reduction. Finally, the high-temperature aging test confirmed an interesting stability of catalytic activity

Washcoating vs. direct synthesis of LaCoO3 on monoliths for environmental applications

A "citrate route"-derived procedure to directly synthesize perovskite catalysts on a cordierite monolith has been developed as a simple, sustainable, fast and reproducible alternative to washcoating. The procedure has been validated with LaCoO3, a well-established perovskite active for oxidation reactions. The activity of LaCoO3 directly synthesized on monolith towards CO and C3s oxidation has been compared both with LaCoO3 powders and LaCoO3/monolith systems obtained by traditional, optimized washcoating procedure. It has been proved that the direct synthesis of the perovskite on the cordierite monolith results in a very uniform, stable catalyst coating, with the same specific activity of powders