Mechanical properties of MWPECVD diamond coatings on Si substrate via nanoindentation

The mechanical properties of polycrystalline diamond coatings with thickness varying from 0.92 to 44.65 μm have been analysed. The tested samples have been grown on silicon substrates via microwave plasma enhanced chemical vapour deposition from highly diluted gas mixtures CH₄-H₂ (1% CH₄ in H₂). Reliable hardness and elastic modulus values have been assessed on lightly polished surface of polycrystalline diamond films.The effect of the coating thickness on mechanical, morphological and chemical-structural properties is presented and discussed. In particular, the hardness increases from a value of about 52 to 95 GPa and the elastic modulus from 438 to 768 GPa by varying the coating thickness from 0.92 to 4.85 μm, while the values closer to those of natural diamond (H = 103 GPa and E = 1200 GPa) are reached for thicker films (> 5 μm). Additionally, the different thickness of the diamond coatings permits to select the significance of results and to highlight when the soft silicon substrate may affect the measured mechanical data. Thus, the nanoindentation experiments were made within the range from 0.65% to 10% of the film thickness by varying the maximum load from 3 to 80 mN.     

Thermoluminescent response of thin (2 µm) polycrystalline diamond films grown by pulsed and continuous microwave plasmas

Polycrystalline diamond films with a thickness of about 2 µm were deposited by chemical vapour deposition on silicon substrates in continuous and pulsed wave regimes with duty cycle between 25% and 100%. The thermoluminescent behaviour of these films was analysed in the temperature range 323–723 K after β irradiation with doses in the range 7–107 Gy. All the films exhibit a dosimetric peak centred at about 592 K, showing a good linearity in the whole investigated dose range. The thermoluminescence analyses show that the intensity of the dosimetric peak is maximum for the continuous wave film, while it decreases for the pulsed wave samples. The variation of the crystalline quality and the purity of the films with the employed duty cycle, investigated via micro-Raman spectroscopy and room-temperature photoluminescence, indicates that the continuous wave (duty cycle = 100%) film has the best quality, corresponding to the highest thermoluminescence efficiency.     

The use of scintigraphy with labelled leukocytes: our experience

The authors describe various applications of scintigraphy with labeled leukocytes and its value in the diagnosis of gut diseases such as Crohn's disease, ulcerative colitis and related complications. Furthermore, the study of vascular prosthesis infection, cryptogenetic fever and abdominal sepsis, three cases of which are herein reported, is facilitated. The method, in conjunction with endoscopy and traditional radiology, revealed to be of great value in terms of sensitivity and specificity for the diagnosis of the aforementioned diseases. Therefore, the use of such method is encouraged in all those cases of abdominal sepsis of uncertain interpretation and in the evaluation of vascular prosthesis infection.     

The colorectal adenoma-carcinoma sequence: the limits between polypectomy and intestinal resection

A hemocytometer-based trypan blue dye exclusion cell quantitation and viability assay was compared with a similar assay using simultaneous fluorometric staining with fluorescein diacetate and propidium iodide. Viable and nonviable cell densities were measured, and culture viability was calculated both during the normal growth cycle of a murine hybridoma and in response to the application of millimolar concentrations of either tert-butyl hydroperoxide or ferrous iron. During the early phase of rapid hybridoma cell growth, assay-based differences in viable cell density were not significant. As the culture aged, the trypan blue dye exclusion assay significantly overestimated cell viability, thereby underestimating nonviable cell density and yielding an erroneous estimation of the overall viability of the culture. Because of its lack of ambiguity in the identification of stained, nonviable cells and its resulting increased accuracy in the estimation of culture viability, the fluorometric assay was considered a better choice for the evaluation of cell viability.     

New packaging strategies to preserve fresh-cut artichoke quality during refrigerated storage

The influence of both post-harvest treatments and film permeability on the quality loss kinetic of minimally processed artichokes is assessed in this study. In particular, fresh-cut artichoke heads were subjected to dipping in citric acid/calcium chloride water solution, and coating with citric acid loaded sodium alginate, respectively. Three different packaging materials were used: a polyester-based biodegradable film, an aluminum-based multilayer film, and a commercially available oriented polypropylene film. Artichokes quality loss kinetic during storage was determined by monitoring produce appearance, weight loss, pH, and viable cell load of the main spoilage microorganisms. Results suggest that among the selected treatments, coating shows the best performance in terms of artichokes shelf life. As far as the packaging material is concerned, the biodegradable film tested in this work seems to be the most suitable packaging to preserve the quality of the coated fresh-cut produce.Industrial relevance: Fresh-cut vegetables market has grown rapidly in recent years as a result of changes in consumer attitudes. There is a real need to find methods for preservation of minimally processed food products that can gain widespread acceptance by the industry. This paper suggests effective packaging solutions to delay the quality decay kinetic of fresh-cut artichokes. Moreover, the present study proposes a new “green packaging system” that could emphasize the relevance of the obtained results due to the increased attention to the environmental impact.     

Discrimination between Southern Italy and foreign milk samples using spectroscopic and analytical data

Determination of the geographical origin of foodstuffs is becoming of increasing interest to consumers and producers, since it may be used as a criterion for certifying quality, authenticity and typicality.     

NASA takes lead U.S. role in Earth observation

The role being played by NASA in preparing for the observance of the International Space Year (ISY) is discussed. Key themes of the inaugural meeting of the Space Agency Forum on ISY (SAFISY), held in Durham, NH, in April 1988, are examined. The thirteen different SAFISY Earth science projects, which are using space technologies to assess such environmental issues as ozone depletion, deforestation, and global warming, are described briefly. An ISY educational campaign, stressing both the scientific results of space exploration and the benefits of space applications, is discussed     

Unveiling the Dynamical Assembly of Magnetic Nanocrystal Zig‐Zag Chains via In Situ TEM Imaging in Liquid

The controlled assembly of colloidal magnetic nanocrystals is key to many applications such as nanoelectronics, storage memory devices, and nanomedicine. Here, the motion and ordering of ferrimagnetic nanocubes in water via liquid‐cell transmission electron microscopy is directly imaged in situ. Through the experimental analysis, combined with molecular dynamics simulations and theoretical considerations, it is shown that the presence of highly competitive interactions leads to the formation of stable monomers and dimers, acting as nuclei, followed by a dynamic growth of zig‐zag chain‐like assemblies. It is demonstrated that such arrays can be explained by first, a maximization of short‐range electrostatic interactions, which at a later stage become surpassed by magnetic forces acting through the easy magnetic axes of the nanocubes, causing their tilted orientation within the arrays. Moreover, in the confined volume of liquid in the experiments, interactions of the nanocube surfaces with the cell membranes, when irradiated at relatively low electron dose, slow down the kinetics of their self‐assembly, facilitating the identification of different stages in the process. The study provides crucial insights for the formation of unconventional linear arrays made of ferrimagnetic nanocubes that are essential for their further exploitation in, for example, magnetic hyperthermia, magneto‐transport devices, and nanotheranostic tools.     

Interaction of Copper Trafficking Proteins with the Platinum Anticancer Drug Kiteplatin

The interaction of metallodrugs with proteins influences their mechanism of action and side effects. In the case of platinum drugs, copper transporters modulate sensitivity and resistance to these anticancer agents. To deepen the knowledge of the structural properties underlying the reactivity of platinum drugs with copper transporters, we studied the interaction of kiteplatin and two of its derivatives with the methionine-rich motif of copper importer Ctr1 and with the dithiol motif of the first domain of Menkes ATPase. Furthermore, cellular uptake and cytotoxicity of the three complexes were evaluated in cisplatin-sensitive and -resistant ovarian cancer cells, comparing the data with those of clinically relevant drugs. Reactivity depends on the tightness of the chelate ring formed by the carrier ligands and the nature of the leaving and entering groups. The results highlight the importance of subtle changes in the platinum coordination sphere that affect drug absorption and intracellular fate.     

Trapped Pore Waters in the Open Proton Channel HV1

The voltage-gated proton channel, H_V1, is crucial for innate immune responses. According to alternative hypotheses, protons either hop on top of an uninterrupted water wire or bypass titratable amino acids, interrupting the water wire halfway across the membrane. To distinguish between both hypotheses, the water mobility for the putative case of an uninterrupted wire is estimated. The predicted single-channel water permeability 2.3 × 10⁻¹² cm³ s⁻¹ reflects the permeability-governing number of hydrogen bonds between water molecules in single-file configuration and pore residues. However, the measured unitary water permeability does not confirm the predicted value. Osmotic deflation of reconstituted lipid vesicles reveals negligible water permeability of the H_V1 wild-type channel and the D174A mutant open at 0 mV. The conductance of 1400 H⁺ s⁻¹ per wild-type channel agrees with the calculated diffusion limit for a ≈2 Å capture radius for protons. Removal of a charged amino acid (D174) at the pore mouth decreases H⁺ conductance by reducing the capture radius. At least one intervening amino acid contributes to H⁺ conductance while interrupting the water wire across the membrane.