Development and characterization of antitumoral electrospun polycaprolactone/functionalized Fe3O4 hybrid membranes

The applicative potentiality of the nanotechnologies emerges more and more in all fields of science, technology, and medicine. In this context, magnetic nanoparticles have been recently proposed as promising nanomaterials to eliminate, through minimally invasive treatments, small tumours. This work deals with the design and realization of electrospun hybrid membranes of Polycaprolactone (PCL) incorporating magnetic nanoparticles modified with the acid citric-based ligand. The nature of the ligand allows very effective compatibility between nanoparticles and hosting fibers, as deducible by the nanoparticles distribution along the fibers. Dimension and functionalization of the nanoparticles, together with the optimization of the electrospinning parameters allow obtaining highly homogeneous distribution in the diameter of the nanocharged fibers, which ranges between 500 nm and 3 μm. The anticancer activity of the optimized electrospun hybrid membranes has been analyzed toward two different melanoma cell lines: the low metastatic A375 and the high metastatic A2058, using the MTT assay. The formulated membrane exhibited a dose-dependent reduction toward both melanoma cells viability, without a decrease of activity compared to the unfunctionalized Fe₃O₄ nanoparticles. Promising results have been obtained also considering the antitumor activity of the hybrid Membranes toward uterine HeLa cells. Magnetic properties and structural and morphological characteristics of the functional membranes highlight very promising applications for tuning/enhancing the nanodelivery of drugs and chemotherapy assisted by electroporation technique.     

Effects of drift angle on model ship flow

The effects of drift angle on model ship flow are investigated through towing tank tests for the Series 60 C_B=0.6 cargo/container model ship. Resistance, side force, drift moment, sinkage, trim, and heel data are procured for a range of drift angles β and Froude numbers (Fr) and the model free condition. Detailed free-surface and mean velocity and pressure flow maps are procured for high and low Fr=0.316 and 0.16 and β=5° and 10° (free surface) and β=10° (mean velocity and pressure) for the model fixed condition (i.e. fixed with zero sinkage, trim, and heel). Comparison of results at high and low Fr and previous data for β=0° enables identification of important free-surface and drift effects. Geometry, conditions, data, and uncertainty analysis are documented in sufficient detail so as to be useful as a benchmark for computational fluid dynamics (CFD) validation. The resistance increases linearly with β with same slope for all Fr, whereas the increases in the side force, drift moment, sinkage, trim, and heel with β are quadratic. The wave profile is only affected near the bow, i.e. the bow wave amplitude increases/decreases on the windward/leeward sides, whereas the wave elevations are affected throughout the entire wave field. However, the wave envelope angle on both sides is nearly the same as β=0°, i.e. the near-field wave pattern rotates with the hull and remains within a similar wave envelope as β=0°. The wave amplitudes are significantly increased/decreased on the windward/leeward sides. The wake region is also asymmetric with larger wedge angle on the leeward side. The boundary layer and wake are dominated by the hull vortex system consisting of fore body keel, bilge, and wave-breaking vortices and after body bilge and counter-rotating vortices. The occurrence of a wave-breaking vortex for breaking bow waves has not been previously documented in the literature. The trends for the maximum vorticity, circulation, minimum axial velocity, and trajectories are discussed for each vortex. Received: 16 September 1999/Accepted: 8 November 2001     

“4,7-lactams”, intermediates for penems synthesis. II. Total synthesis of (+)-2,2-dimethyl-9-oxo-3-oxa-6-thia-1-azabicyclo [5.2.01,7]nonane

The total synthesis of chiral “4,7-lactam” $\text{4}$ has been accomplished starting from 4-acetoxyazetidinone. An independent route from methyl penicillanate has been used to test the efficiency of the foregoing synthesis.     

The space of general conservation laws and topology changes

We construct a 5D space in which conservation laws are always and absolutely valid. This general result holds also scaling in 4D space even inducing, when necessary, changes of topology. The inequality of representations of physical laws in 4D and in 5D generalized spaces is founded not on phenomenological but on mathematical results. Essentially, the mechanism is based on the fact that we take into account also transformations where the Jacobian of the change of variables can assume null values. We derive that stress-energy and metric tensors, due to Bianchi identities, are always conserved through the mechanism presented in the following based on the fact that we introduce transformations with null Jacobian in the space definition. Moreover, in the case of metric tensor, conservation is a necessary feature in order to have physically defined theories.     

Heterogeneous Fenton reactants: a study of the behavior of iron oxide nanoparticles obtained by the polymeric precursor method

Nanoparticles composed of iron oxides and iron salts were obtained from polymeric resins produced by polymerizing Fe²⁺-citrate and Fe³⁺-citrate complexes with ethylene glycol. The citric acid:Fe molar ratio was varied to obtain different synthesis conditions. The materials were treated at 450 °C for 2 h to obtain nanoparticles, which were characterized by XRD, Mössbauer spectroscopy, FEG, CHNS, atomic absorption and surface area through N₂ physisorption. Rhodamine B photo degradation in the presence of these nanoparticles and hydrogen peroxide was carried out to analyze the possible behavior of nanoparticles as heterogeneous Fenton reactants. UV–visible spectroscopy revealed that the catalytic activity in the presence of nanoparticles obtained with a citric acid:Fe molar ratio of 12:1 was the condition that provided the best results in this work.     

Calotte regolari tridimensionali del secondo ordine

Sunto Nella presente Memoria determino gli enti geometrici che permettono la caratteriz zazione rispetto algruppo proiettivo dei vari tipi di calotte σ ₃ ² (o intorno del secondo ordine di un punto regolare di una varietà V₃). Le proprietà dei detti enti si riflettono in proprietà delle σ ₃ ² e pertanto la Memoria completa lo studio delle dette σ ₃ ² . Assegno inoltre i criteri che permettono di trasportare le proprietà ed i risultati ottenuti nel caso proiettivo alla caratterizzazione ed allo studio rispetto allaTopologia differenziale delle coppie di σ ₃ ² tangenti.     

Mechanism of the hydroxycarbonylation of 1-hexene catalyzed by immobilized rhodium complexes of pyridine ligands

Summary In this work, a mechanistic study of the hydroxycarbonylation of 1-hexene to heptanoic acid and the water gas shift reaction (WGSR) catalyzed by the rhodium(I) complexes, [Rh(COD)(amine)₂](PF₆) (COD = 1,5-cyclooctadiene, amine = 4-picoline, 3-picoline, 2-picoline, pyridine, 3,5-lutidine or 2,6-lutidine) immobilized on poly(4-vinylpyridine) in contact with water under CO is discussed. Catalytic cycles for these reactions bearing common Rh-H catalytic species are proposed.     

Electron and phonon relaxation in metal films perturbed by a femtosecond laser pulse

A theoretical investigation of the electron and phonon time-dependent distributions in an Ag film subjected to a femtosecond laser pulse has been carried out. A system of two coupled time-dependent Boltzmann equations, describing electron and phonon dynamics, has been numerically solved. In the electron Boltzmann equation, electron–electron and electron–phonon collision integrals are considered together with a source term for laser perturbation. In the phonon Boltzmann equation, only electron–phonon collisions are considered, neglecting laser perturbation and phonon–phonon collisions. Screening of the interactions has been accounted for in both the electron–electron and the electron–phonon collisions. The results show the simultaneous electron and phonon time-dependent distributions from the initial non-equilibrium behaviour up to the establishment of a new final equilibrium condition. PACS 72.10.-d; 71.10.Ca; 63.20.Kr