Molecular coating of nanoparticles represents probably the most important and, at the same time, critical step to design new nanostructured magnetic materials. The interaction between molecules and surface atoms leads to a strong modification of surface magnetic properties, that are one of the key points in the physics of magnetic nanoparticles. In this paper the magnetic properties of CoFe2O4 nanoparticles (⟨D⟩ ≅ 4–8 nm) coated with oleic acid have been investigated in order to clarify the role of the molecular coating on the interparticle interactions and surface anisotropy. An increase of magnetic anisotropy (i.e., coercive field and anisotropy constant) with particle size is observed in coated nanoparticles, indicating that the magnetic anisotropy is governed mainly by its magneto-crystalline component. The removal of molecular coating induces a strong increase of anisotropy, because of the increase of its surface component, as indicated by the increase of exchange bias field.

This paper focuses on the magnetic properties of CoFe 2 O 4 nanoparticles, discussing the influence of nanoparticles arrangements obtained by different synthesis methods. Using high thermal decomposition (HTD) and direct micellar (DM) routes, three samples of CoFe 2 O 4 nanoparticles with equal primary particle size (∼5 nm) were prepared. The HTD method allows one to obtain highly crystalline primary nanoparticles coated by oleic acid organized in a self-assembling arrangement (ACoFe HTD ). The DM method results to be appropriate to prepare either irregular arrangements (IACoFe DM ) or spherical iso-oriented nanoporous assemblies (SACoFe DM ) of primary CoFe 2 O 4 nanocrystals. Despite the same particle size, magnetization measurements of the HTD sample show a tendency toward cubic anisotropy (M r / M s ≈ 0.7), while in DM samples, a uniaxial anisotropy (M r /M s ≈ 0.4) is observed. The comparison between IACoFe DM and SACoFe DM samples indicates that the ordering of nanocrystals at the mesoscopic scale induces an increase of the coercive field (μ 0 H c ≈ 1.17 T → μ 0 H c ≈ 1.45 T) and of the reduced remanent magnetization (M r /M s ≈ 0.4 → M r /M s ≈ 0.5). The reason for these differences is discussed. In particular, a detailed study on interparticle interactions is carried out, highlighting the influence of the molecular coating and the formation of spherical iso-oriented assemblies.

Spherical nanoparticles of surfactant-coated CoFe 2 O 4 (core) were prepared through thermal decomposition of metal acetylacetonates in the presence of a mixture of oleic acid and oleylamine and uniformly coated with silica shell by using tetraethylorthosilicate (TEOS) and ammonia in a micellar solution (core/shell). Transmission electron microscopy (TEM) analysis of core/shell nanoparticles evidenced the high homogeneity of the coating process in producing single core/shell nanoparticles with a narrow size distribution. The combined use of spectroscopic studies (NMR and FTIR) on core and core/shell nanoparticles pointed out that the surfactants' layer bound to the surface core nanoparticles is retained also after the silica coating process. This allows to obtaining systems with very similar magnetic behavior but weaker dipolar interparticle interactions and lower values of saturation magnetization. In view of the interest in biomedical field, the effect of the CoFe 2 O 4 nanoparticles silica coating was also studied by controlling the possible modifications in cytotoxicity by trypan blue and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assays on human cells.

This paper focuses on the study of the magnetic properties of 9 nm magnetite nanocrystals. XRD and TEM measurements indicate the presence of crystalline particles, with a fraction of them only partially crystallized or highly defective. The analysis of the temperature dependence of the zero-field-cooled/field-cooled magnetization and of the thermoremanent magnetization provides evidence of the existence of three magnetic regimes: a high temperature regime (300-100 K), an intermediate regime (100-20 K), and a low temperature regime (below 20 K). The characteristics of such regimes are discusse

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In recent months, there have been reported several dermatologic manifestations in COVID-19 patients such as erythematous rash, widespread urticarial, chickenpox-like vesicles, acroischemia, chilblainlike eruptions and petechial rash mimicking dengue. 1,2 In this study, we present a case of alopecia areata (AA) in a patient who tested positive for COVID-19. Our purpose is to further characterize dermatologic manifestations of this disease.At the end of September, a 38-year-old healthy male patient presented to the dermatologic department because of sudden appearance of bald spots affecting the beard.The patient had been diagnosed with SARS-CoV-2 infection in August, a month before the appearance of the bald spots.

We studied telomere length in 32 CML patients who discontinued imatinib after achieving complete molecular remission and 32 age-sex-matched controls. The relative telomere length (RTL) was determined by q-PCR as the telomere to single copy gene (36B4) ratio normalized to a reference sample (K-562 DNA). Age-corrected RTL (acRTL) was also obtained. The 36-month probability of treatment-free remission (TFR) was 59.4 %. TFR patients showed shorter acRTL compared to relapsed (mean ± SD = 0.01 ± 0.14 vs 0.20 ± 0.21; p = 0.01). TFR was significantly higher in CML patients with acRTL ≤0.09 (78.9 vs 30.8 %, p = 0.002). CML stem cells harboring longer telomeres possibly maintain a proliferative potential after treatment discontinuation.Electronic supplementary materialThe online version of this article (doi:10.1186/s13045-016-0293-y) contains supplementary material, which is available to authorized users.

Data on the occurrence and distribution of alien freshwater fishes in Sardinia are provided based on historical data and recent reports. A total of 14 introduced fish species are established in Sardinian fresh waters. These species comprise members of the Cyprinidae (carp, Cyprinus carpio; tench, Tinca tinca; goldfish, Carassius auratus; rudd, Scardinius erythrophthalmus; bleak, Alburnus alburnus alborella), Centrarchidae (pumpkinseed, Lepomis gibbosus; largemouth bass, Micropterus salmoides), Salmonidae (rainbow trout, Oncorhynchus mykiss; brown trout, Salmo trutta), Cobitidae (spined loach, Cobitis taenia), Ictaluridae (black bullhead, Ameiurus melas), Percidae (European perch, Perca fluviatilis), and Poeciliidae (mosquitofish, Gambusia holbrooki). The species most recently introduced into Sardinia is the topmouth gudgeon, Pseudorasbora parva (Cyprinidae). The majority of alien fishes documented here match those that have already established self-maintaining populations elsewhere in Mediterranean-type eco-regions. Since the late nineteenth century, fish identified as potential sources of food have been introduced for aquaculture and stock enhancement purposes. Other introductions have subsequently occurred for the purposes of biological control, ornamental use or sport fishing activities. Some species are notably widespread and common (e.g. mosquitofish and tench), whereas the presence of others seems to be more restricted and may still be confined to a few hydrographic regions (e.g. bleak, rudd, pumpkinseed and topmouth gudgeon