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.

Changes in extra-virgin olive oil added with Lycium barbarum L. carotenoids during frying: Chemical analyses and metabolomic approach.

In this work, an Italian extra-virgin olive oil (EVOO) sample and the same sample added with a carotenoid-rich nutraceutical extract from Lycium barbarum L. (EVOOCar) were subjected to a frying process to comparatively assess chemical and physical changes and heat stability. Oxidation progress was monitored by measuring oil quality changes such as peroxide value, free acidity, K232, K268, and fatty acid composition as well as minor compound content, phenols, α-tocopherol, and carotenoids. An UHPLC/QTOF-MS metabolomics approach discriminated the two oil samples based on their chemical changes during frying, identifying also the phenolic classes most exposed to statistically significant variations. Partial least square discriminant analysis and volcano analysis were applied together to identify the most significant markers allowing group separation. The decrease in total phenolic content was lower in EVOOCar than in EVOO during frying. Monounsaturated and polyunsaturated fatty acids showed a significant percentage loss, 3.7% and 17.2%, respectively, in EVOO after 180min frying at 180°C, while they remained constant or slightly changed in EVOOCar. Zeaxanthin added to the oil rapidly decreased during the frying process. These findings showed that the addition of a carotenoid extract from L. barbarum can help to improve the oxidative stability of extra-virgin olive oil.

Structural and spectroscopic properties of pure and doped Ba6Ti2Nb8O30 tungsten bronze.

Pure and doped Ba(6)Ti(2)Nb(8)O(30) (BTN), obtained by substituting M = Cr, Mn, or Fe on the Ti site (Ba(6)Ti(2-x) M(x)Nb(8)O(30), x = 0.06 and 0.18) and Y and Fe on the Ba and Ti sites, respectively (Ba(6-x)Y(x)Ti(2-x)Fe(x)Nb(8)O(30), x= 0.18), are synthesized. The influence of cation doping on the local structure, the cation oxidation state, and the possible defect formation able to maintain the charge neutrality are investigated by spectroscopic (electron paramagnetic resonance (EPR) and micro-Raman), structural (X-ray powder diffraction) and transport (impedance spectroscopy, thermoelectric power) measurements, in the temperature range of 300-1200 K in air and N(2) flow. Starting from the valence state of the doping ions (Fe(3+), Cr(3+), and Mn(2+)), determined by EPR, and from thermoelectric power measurements, evidencing a negative charge transport, different charge-compensating defect equilibria, based on the creation of positive electron holes or oxygen vacancies and electrons, are discussed to interpret the conductivity results.

Transport and structural properties of pure and Cr doped Li3VO4.

This study deals with the effects of 5 and 10% chromium additions on the transport and structural properties of Li3VO4. The Cr substitution is easily obtained without impurity phases and does not affect the room- and high-temperature host crystal structure, as evidenced by X-ray powder diffraction and micro-Raman analysis. The EPR signals are interpreted in terms of quantified amounts of Cr ions in 5+ and 3+ valence states. Suitable 7Li and 51V MAS NMR spectra simulations agree with the EPR results about the relative amount of Cr5+ and Cr3+ ions substituted in V5+ and Li+ sites, respectively. The Cr3+ presence on Li site, also suggested by Raman results and Rietveld refinements, requires Li vacancies to maintain the charge neutrality. The p-type conductivity, suggested by the positive thermoelectric power coefficients, significantly increases by the cation doping up to an order of magnitude.

[The neuroleptic malignant syndrome (NMS). A report of a clinical case with a protracted and recurrent course. A review of the literature]. / Sindrome maligna da neurolettici (SMN). Descrizione di un caso clinico a decorso protratto e recidivante. Rassegna della letteratura.

Neuroleptic malignant syndrome (NMS), characterized by catatonic behavior, generalized muscular rigidity, hyperthermia and autonomic dysfunction, can suddenly arise in patients treated with neuroleptic agents and carries a high mortality rate even today. A case of NMS due to i.m. therapy with haloperidol decanoate is reported in this paper, characterized by sustained course and a severe relapse due to a different therapy with another neuroleptic agent. The patient however, after a prolonged remission from the relapse, was able to resume long term therapy with neuroleptic drugs. The importance of monitoring blood levels of CPK during the follow-up and the effectiveness of therapy with bromocriptine and dantrolene in confirmed. Although the patient presented a good clinical response, she developed permanent cerebral and muscular damage. A wide review of the literature on NMS is reported to throw light on this syndrome, whose recognition and prompt diagnosis are necessary to reduce mortality.

Recurrent familial neuropathy due to liability to pressure palsies.

Two families with hereditary neuropathy with liability to pressure palsies (HNPP) were evaluated clinically, electrophysiologically and pathologically (2 index cases). Familial patterns suggest autosomal dominant inheritance. The clinical presentation is characteristic, with recurrent painless transitory mononeuropathy, without evident triggering factors, or caused by trivial trauma or pressure. In affected members neurophysiological studies showed diffuse slowing in nerve conduction, more evident at common sites of entrapment. Somatosensory evoked potentials (SEPs) showed bilateral peripheral abnormalities with proximal nerve involvement more pronounced in older patients. 40 to 75% of teased fibers displayed sausage-shaped swellings. Ultrastructurally some sausages showed redundant myelin loops and excessive number of myelin lamellae that seem to cause axonal constriction.