Preparation and characterizations of soluble regularly alternating polyazomethines from oligothienylenes

The preparation and characterization of oligothienylene dialdehydes and related soluble copolymers in which thenylenic segments regularly alternate with phenylenic portions linked by azomethine moieties is presented. The polymer series with three, six and eight thienylenic residues showed interesting evidences of electronic confinement in low-gap segments (thienylenic). Self-assembled structures of oligomers can be obtained either by evaporation in high vacuum or by a proper thermal treatment of spin coated films, depending on the molecule length. Polymers prepared by different synthetic routes show different thermal and structural properties as a function of the ratio of two possible isomers at imino linkage. The order degree also influences the optical properties in fact luminescence data are strictly related to the percentage of the two isomers.     

Gold(III) compounds as anticancer drugs

Gold(III) complexes constitute a new class of metallodrugs, of potential interest for cancer treatment. During the past decade different kinds of gold(III) complexes have been reported to be appreciably stable under physiological-like conditions and to manifest relevant antiproliferative properties against selected human tumor cell lines. Some relevant examples are presented. Recent investigations point out that the interactions of cytotoxic gold(III) complexes with DNA are significantly different and weaker than those of platinum analogues; important interactions with model proteins and target proteins have been reported as well. Accordingly, the mechanisms of action of cytotoxic gold(III) complexes seem to be innovative and substantially different from that of cisplatin. Relevant antimitochondrial effects were demonstrated in some cases, eventually leading to cell apoptosis.     

Design and characterization of a chitosan physical gel promoting wound healing in mice

In this study, a sterile and biocompatible chitosan (CHI) gel for wound healing applications was formulated. CHI powder was treated in autoclave (ttCHI) to prepare sterile formulations. The heat treatment modified the CHI molecular weight, as evidenced by GPC analysis, and its physical–chemical features. Differential scanning calorimetry studies indicated that the macromolecules, before and after thermal treatment, differ in the strength of water-polymer interaction leading to different viscoelastic and flow properties. Thermally treated CHI exhibited the following effects: (i) increased the proliferation and migration of human foreskin foetal fibroblasts at 24 h; (ii) accelerated wound healing (measured as area of lesion) at 3 and 10 days in an in vivo model of pressure ulcers. These effects were linked to the increase of the hydroxyproline and haemoglobin content as well as Wnt protein expression. Moreover, we found a reduction of myeloperoxidase activity and TNF-α mRNA expression. These observations suggest the potential of this novel CHI gel in wound healing and other therapeutic applications.     

Elastomeric electrospun scaffolds of poly(<Emphasis Type="SmallCaps">l</Emphasis>-lactide-<Emphasis Type="Italic">co</Emphasis>-trimethylene carbonate) for myocardial tissue engineering

In myocardial tissue engineering the use of synthetically bioengineered flexible patches implanted in the infarcted area is considered one of the promising strategy for cardiac repair. In this work the potentialities of a biomimetic electrospun scaffold made of a commercial copolymer of (l)-lactic acid with trimethylene carbonate (P(l)LA-co-TMC) are investigated in comparison to electrospun poly(l)lactic acid. The P(l)LA-co-TMC scaffold used in this work is a glassy rigid material at room temperature while it is a rubbery soft material at 37°C. Mechanical characterization results (tensile stress–strain and creep-recovery measurements) show that at 37°C electrospun P(l)LA-co-TMC displays an elastic modulus of around 20 MPa and the ability to completely recover up to 10% of deformation. Cell culture experiments show that P(l)LA-co-TMC scaffold promotes cardiomyocyte proliferation and efficiently preserve cell morphology, without hampering expression of sarcomeric alpha actinin marker, thus demonstrating its potentialities as synthetic biomaterial for myocardial tissue engineering.     

Online comprehensive RPLC × RPLC with mass spectrometry detection for the analysis of proteome samples

LC-MS-based shotgun proteomics relies both on the power of the separation techniques and the sensitivity of detection methods. As a viable alternative to classical approaches in this field, we developed a fully automated, comprehensive 2D LC system, in which RPLC × RPLC was coupled to MS detection, for the first time, and applied for the analysis of tryptic digests obtained from α-casein and dephosphorylated α-casein. The use of a significantly different pH in the two dimensions allowed us to attain high peak capacity, despite the employment of novel identical stationary phases. Furthermore, such a combination addresses compatibility issues, thus allowing straightforward interfacing in online 2D LC configuration, as well as direct linkage to a mass spectrometer. A theoretical peak capacity of ca. 8500 was calculated for the setup, employing four serially coupled C18 columns in the first dimension (600 × 2.1 mm, 2.7 μm d.p.), operated under basic conditions, and 3 cm length of the same stationary phase (30 × 4.6 mm, 2.7 μm d.p. column), under acidic conditions, for fast second dimension analysis.     

Local Measurements of Temperature Changes Associated with the Stress-Induced Tetragonal to Monoclinic Transformation in Zirconia

An experimental arrangement capable of monitoring temperature changes from 0.01 to 0.1 K has been successfully tested for registering the temperature evolution occurring during the tetragonal to monoclinic transformation of an alumina/ceria-stabilized tetragonal zirconia polycrystal (Al₂O₃/Ce-TZP). The arrangement is based on a very small thermistor. The data obtained have been used for evaluating the thermal diffusivity of the Al₂O₃/Ce-TZP composites.     

Pulmonary function tests as a predictor of chronic lung disease in ventilated preterm infants

BACKGROUND: The objective of this study was to determine if the value of respiratory system compliance and lung resistance could be a good predictor of chronic lung disease (CLD) in an early stage of this disease. METHODS: The study was carried out on 48 preterms infant (BW < 1500 g) who were ventilated for respiratory distress, calculating pulmonary mechanics at 3, 5, 7 and 10 days of life with a standardized protocol of measurements. RESULTS: Infants who did not develop CLD showed higher values of respiratory system dynamic compliance (Crsdyn) than the CLD group since the 5th day of life (p < 0.001). The values of lung resistance show a statistical significant difference between groups since the 7th day of life. CONCLUSIONS: These findings indicate that, with a well standardized method of measurements, the value of Crsdyn can well be a good predictor and a sensible prognostic factors for CLD.     

Current noise in MgB2 superconducting thin films

In this paper we present some experimental results concerning the current noise produced during the resistive transition in MgB₂ thin films. Preliminary investigations evidenced the presence of electrical noise whose power spectrum has a region of the 1/fⁿ type with n 3. We suggest that the noise may originate from abrupt rearrangement of the current distribution inside the specimen during the percolative process of a diphasic system. Experimental measurements of the spectral components of the current noise taken during the resistive transition will be given and discussed.     

Immunity tests of implantable cardiac pacemaker against CW and pulsed ELF fields: experimental and numerical results

The aim of the present work is to investigate pacemaker (PMK) immunity against high-level extremely low frequency (typically 50 Hz) magnetic fields that can be found in industrial environment where high power machines operate. To that purpose, a test bench has been set up using a Helmholtz coil for producing extremely low frequency magnetic fields and a trunk simulator rightly fed by cardiac signals. A widely used PMK was tested, and results have been reported, under different operating conditions, for both continuous waves and variously pulsed excitations. A numerical tool has also been developed to analyze the realized test bench, based on a proper discretization of a human trunk simulation and on the construction of an equivalent three-dimensional (3-D) network. Numerical results have showed a good agreement with the experimental results.     

Characterization of superconducting thin films by Mo75Re25 target for rf cavity applications

superconducting thin films by Mo₇₅Re₂₅ single-target magnetron sputtering at various temperatures on sapphire substrates were prepared. Sharp superconductive transitions andT _c values above 10 K were achieved, and the deposited films showed a good metallic behavior. According to structural analyses (EDS and X-rays), all the samples have the same stoichiometry as the target and, even at low deposition temperatures, they exhibit theA15 phase. From measured residual resistivities and superconducting critical temperatures the theoretical BCS surface resistances were estimated and compared to those o Mo₆₀Re₄₀ films, presented in a previous work. Both these alloys, in fact, being characterized by low surface resistances and high critical fields, are good candidates as coating films in r.f. cavities.