X-ray Diffraction Methodology for the Microstructural Analysis of Nanocrystalline Powders: Application to Cerium Oxide

The microstructural evolution of nanocrystalline ceria produced by sol–gel has been analyzed as a function of the calcination temperature employing a novel nondestructive method based on the modeling of the whole X-ray diffraction pattern. The results have been thoroughly verified by transmission electron microscopy. A variation both in the average size and in the distribution of the crystalline domains is evidenced. In addition, information concerning lattice defects can be inferred on a larger scale than that normally accessible by microscopy techniques.     

Recent inversion procedures for microwave imaging in biomedical, subsurface detection and nondestructive evaluation applications

Systems for electromagnetic imaging at microwave frequencies are of great interest in many applications ranging from industrial diagnostics to subsurface inspection and medical imaging. The development of efficient inverse-scattering-based procedures represents a critical aspect, due to the difficulties inherent in this nonlinear ill-posed problem. In this paper, some of the recently proposed inversion methods (both nonlinear and linearized) for two-dimensional imaging are reviewed. Concerning industrial imaging, nondestructive evaluation and medical diagnostic, tomographic approaches are presented, whereas for the inspection of buried inhomogeneities, tomographic and borehole-configurations are considered. In particular, deterministic and stochastic approaches are discussed and the most specific features of these approaches are pointed out. Finally, the issue of data collection, which is another key point of microwave imaging system, is briefly addressed, with particular emphasis on approaches based on the modulated scattering technique, which is a promising technique strongly related to electromagnetic scattering concepts.     

Natural compounds to preserve fresh fish burgers

Natural antimicrobial compounds to control the quality decay of a fresh fish burger were studied. In particular, thymol, lemon extract and grape fruit seed extract (GFSE), at 20, 40 and 80 ppm, have been tested against the main spoilage microorganisms inoculated in fish burgers stored at 5 °C. The evolution of mesophilic and psychrotrophic bacteria was also monitored. The sensorial quality decay was determined by means of a panel test, which assessed odour, colour, texture, drip loss and general appearance during the storage period. Results show that all the active substances efficiently slowed down the growth of the spoilage microorganisms. In particular, GFSE was the most efficient against Photobacterium phosphoreum , Shewanella putrefaciens and mesophilic bacteria, whereas thymol was the most efficient against both psychrotrophic bacteria and Pseudomonas fluorescens . Microbial growth was the factor limiting fresh fish burger acceptability.     

Preeclampsia, lipid peroxidation, and calcium adenosine triphosphatase activity of red blood cell ghosts

1. The effects of oxatriazole-type (GEA 3162 and GEA 5624) nitric oxide (NO) donors on mitogenesis and proliferation were studied in vascular smooth muscle cell (VSMC) culture. The effects of the GEA-compounds were compared with well-known NO-donors 3-morpholinosydnonimine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP). 2. All NO-donors released NO and increased the production of cyclic GMP concentration-dependently. The production of cyclic GMP was inhibited by the guanylate cyclase inhibitor, ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one). 3. The NO-donors inhibited basal and serum-induced DNA synthesis concentration-dependently. The GEA-compounds were needed in concentrations 10 times lower than SIN-1 and SNAP. GEA 3162, SIN-1 and SNAP were also able to inhibit serum-induced cell proliferation. GEA 5624 was ineffective. The antimitogenic effect of NO-donors was not reduced by inhibiting the guanylate cyclase. 4. These results suggest that NO inhibits serum-induced DNA synthesis and proliferation of VSMC by a cyclic GMP-independent mechanism. The oxatriazole-type NO-donor GEA 3162 was found to be a more potent inhibitor of mitogenesis and cell proliferation than SIN-1 and SNAP.     

Spectroscopic studies and first-principles modelling of 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD) and TTD-TFE copolymers (Hyflon AD)

Amorphous fluorinated optical polymers, characterized by high transparency in the visible and near infrared spectra, high glass transition temperature and very good resistance to chemical environment, have been developed by co-polymerisation of tetrafluoroethylene (TFE) and 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD). In this work we study at molecular level the effect of the introduction of the bulky TTD unit in a perfluoroalkyl chain.In particular the effect on the molecular structure and chain flexibility is investigated and spectroscopic markers correlated to chemical and structural defects are identified. The study includes a thorough experimental spectroscopic analysis (infrared and Raman spectra) of several different copolymer samples and a modelling based on Density Functional Theory calculations and semiempirical calculations on suitable model molecules.     

H mesh prosthesis in the treatment of ventral hernia

The Authors report their experience in the treatment of ventral hernias using a Marlex mesh moulded in an original way with a technique partially derived from plastic surgery. The complete mobilization of the umbilicus through a circular incision allows to fit this prosthesis symmetrically below the rectus abdominis muscles for the entire extension of the hernia.     

Storage-time effects on olive oil DNA assessed by Amplified Fragments Length Polymorphisms

In this study Amplified Fragments Length Polymorphisms (AFLPs) analysis was applied on DNA extracted from different monovarietal olive oils. The aim was to study how the length of storage after milling of the oil can affect the use of DNA as an analyte for molecular traceability. Results, all assessed by statistical analyses, showed that the authentication of olive oil with molecular methods should be performed within a month from olive oil production. After this period, a significant decrease of quality of DNA extracted from olive oil was observed, with a consequent loss of information, that can affect the reliability of the results.     

Shelf life of ready to use peeled shrimps as affected by thymol essential oil and modified atmosphere packaging

In this work the influence of different packaging strategies on the shelf life of ready to use peeled shrimps was investigated. First, the effectiveness of the coating (Coat) and the active coating loaded with different concentrations of thymol (Coat-500, Coat-1000, and Coat-1500) on the quality loss of the investigated food product packaged in air was addressed; afterwards, the thymol concentration that had shown the best performance was used in combination with MAP (5% O₂; 95% CO₂). Microbial cell load of main spoilage microorganisms, pH and sensorial quality were monitored during the refrigerated storage. Results of the first step suggested that the sole coating did not affect the microbial growth. A slight antimicrobial effect was obtained when the coating was loaded with thymol and a concentration dependence was also observed. Moreover, the active coating was effective in minimizing the sensory quality loss of the investigated product, it was particularly true at the lowest thymol concentration. In the second step, the thymol concentration (1000 ppm) that showed the strike balance between microbial and sensorial quality was chosen in combination with MAP. As expected, MAP significantly affected the growth of the mesophilic bacteria. In particular, a cell load reduction of about 2 log cycle for the samples under MAP respect to that in air was obtained. Moreover, the MAP packaging inhibited the growth of the Pseudomonas spp. and hydrogen sulphide-producing bacteria. The MAP alone was not able to improve the shelf life of the uncoated samples. In fact, no significant difference between the control samples packaged in air and MAP was observed. Whilst, the use of coating under MAP condition prolonged the shelf life of about 6 days with respect to the same samples packaged in air. Moreover, when the MAP was used in combination with thymol, a further shelf life prolongation with respect to the samples packaged in air was observed. In particular, a shelf life of about 14 days for the active coating under MAP compared to the same samples in air (5 days) was obtained.     

Exfoliated/Intercalated Rubber/Organo‐Montmorillonite Nanocomposites: Preparation and Characterization

The preparation of new rubber based nanocomposites by using properly modified organophilic clays is described. A commercial organophilic montmorillonite containing a hydroxylated ammonium ion is reacted with LPBs. The reaction causes a decrease of the polarity of the clay and a great increase of the interlayer distance. The modified organoclays are successfully dispersed into rubber matrices (SBR or BR) by melt blending in an internal batch mixer. SAXS analyses and TEM micrographs revealed the formation of highly exfoliated nanocomposites containing intercalated stacks made of few lamellae.