Memory and superposition in a superspin glass.

The non-equilibrium dynamics of the superspin glass state of a dense assembly of ~ 2 nm MnFe2O4 nanoparticles was investigated by means of magnetization, ac susceptibility and Mössbauer spectroscopy measurements and compared to the results of Monte Carlo simulations for a mesoscopic model that includes particles morphology and interparticle interactions. The zero-field cooled (ZFC), thermoremanent (TRM), and isothermal remanent magnetization (IRM) were recorded after specific cooling protocols and compared to those of archetypal spin glasses and their dimensionality. The system is found to display glassy magnetic features. We illustrate in detail, by a number of experiments, the dynamical properties of the low-temperature superspin glass phase. We observe that these glassy features are quite similar to those of atomic spin glasses. Some differences are observed, and interestingly, the non-atomic nature of the superspin glass is also reflected by an observed superspin dimensionality crossover. Monte Carlo simulations-that explicitly take into account core and surface contributions to the magnetic properties of these ultrasmall nanoparticles in direct contact, as well as interparticle interactions-evidence effects of the interplay between (intraparticle) core/surface exchange coupling and (interparticle) dipolar and exchange interactions.

Magnetic Metal-Organic Framework Composite by Fast and Facile Mechanochemical Process.

Magnetic porous metal-organic framework nanocomposite was obtained by an easy, efficient, and environmentally friendly fabrication method. The material consists in magnetic spinel iron oxide nanoparticles incorporated in an iron(III) carboxylate framework. The magnetic composite was fabricated by a multistep mechanochemical approach. In the first step, iron oxide nanoparticles were obtained via ball milling inducing mechanochemical reaction between iron chlorides and NaOH using NaCl as dispersing agent. Magnetic nanoparticles (MNs) were functionalized by neat grinding with benzene-1,3,5-tricarboxylic acid (1, 3, 5 BTC) and were then subjected to liquid assisted milling using hydrated FeCl3, water, and ethanol to obtain a magnetic framework composite (MFC) consisting of iron oxide nanoparticles encapsulated in a MOF matrix. We report, for the first time, the applicability of the grinding method to obtain a magnetic composite of metal-organic frameworks. The synthesized material exhibits magnetic characteristics and high porosity, and it has been tested as carrier for targeted drug delivery studying loading and release of a model drug (doxorubicin). Developed systems can associate therapeutics and diagnostics properties with possible relevant impact for theranostic and personalized patient treatment. Furthermore, the material properties make them excellent candidates for several other applications such as catalysis, sensing, and selective sequestration processes.

Factors associated with severity in invasive community-acquired Staphylococcus aureus infections in children: a prospective European multicentre study.

Staphylococcus aureus is the main pathogen responsible for bone and joint infections worldwide and is also capable of causing pneumonia and other invasive severe diseases. Panton-Valentine leukocidin (PVL) and methicillin-resistant S. aureus (MRSA) have been studied as factors related with severity in these infections. The aims of this study were to describe invasive community-acquired S. aureus (CA-SA) infections and to analyse factors related to severity of disease. Paediatric patients (aged 0-16 years) who had a CA-SA invasive infection were prospectively recruited from 13 centres in 7 European countries. Demographic, clinical and microbiological data were collected. Severe infection was defined as invasive infection leading to death or admission to intensive care due to haemodynamic instability or respiratory failure. A total of 152 children (88 boys) were included. The median age was 7.2 years (interquartile range, 1.3-11.9). Twenty-six (17%) of the 152 patients had a severe infection, including 3 deaths (2%). Prevalence of PVL-positive CA-SA infections was 18.6%, and 7.8% of the isolates were MRSA. The multivariate analysis identified pneumonia (adjusted odds ratio (aOR) 13.39 (95% confidence interval (CI) 4.11-43.56); p 0.008), leukopenia at admission (<3000/mm(3)) (aOR 18.3 (95% CI 1.3-259.9); p 0.03) and PVL-positive infections (aOR 4.69 (95% CI 1.39-15.81); p 0.01) as the only factors independently associated with severe outcome. There were no differences in MRSA prevalence between severe and nonsevere cases (aOR 4.30 (95% CI 0.68- 28.95); p 0.13). Our results show that in European children, PVL is associated with more severe infections, regardless of methicillin resistance.

[Is hypereosinophilic syndrome a potentially malignant condition?]. / E la sindrome ipereosinofila una condizione potenzialmente maligna?

The existence of eosinophilic leukemia (EL) has been controversial since it was first described. Recently, some authors have suggested that EL is part of a spectrum of eosinophilic diseases termed hypereosinophilic syndrome (HS). EL diagnosis is very difficult, especially if abnormal chromosome are not present, because HS comprises multiple disease entities of unclear etiology with the common features of prolonged eosinophilia of undetectable cause and organ system dysfunction. We present a case of HS whose findings are consistent with a leukemic process. For two years the patient showed only sharp hypereosinophilia; his clinical course was then marked by signs and symptoms of granulocytic sarcoma (GS), an extramedullary tumor composed of granulocytic precursor cells. GS as a complication of EL was described and in some cases the diagnosis of leukemia was made only on the basis of the GS complication. The formation of eosinophilic GS also suggests a diagnosis of LE in our case of HS. Finally, we always consider HS as a potential malignant disease.

[Idiopathic hepatosplenic granulomatosis]. / Granulomatosi epatosplenica idiopatica.

Granulomas in the liver are identified in 3-10% of all liver biopsies. Although granulomas frequently represent a sign of either infectious or non infectious disease, 20% of the hepatic granulomas lack an identifiable etiology. These cases are defined as idiopathic granulomatous hepatitides (IG). We describe four cases of disease resembling a lymphoid malignance in which IG could be diagnosed by laboratory, radiological (XR, CT), ultrasonographic, histological and follow-up studies of the patients. We suggest that IG may be suspected in patients with granulomas in the liver, self-limited fever of unknown origin, low epatosplenomegaly, eosinophilia less than 5%, in the absence of infectious, lymphoid or sarcoid diseases. We recommend laparascopy as an important diagnostic tool.

Guillain-Barré syndrome with autoimmune hemolytic anemia following acute viral hepatitis.

A patient with Guillain-Barré syndrome associated with autoimmune hemolytic anemia following post-transfusional acute viral HBsAg- positive hepatitis improved dramatically and subsequently recovered from both diseases after plasmapheresis and steroid therapy. This case supports an autoimmune mechanism of Guillain-Barré syndrome.