Synthesis and Evaluation of Voltage-Gated Sodium Channel Blocking Pyrroline Derivatives Endowed with Both Antiarrhythmic and Antioxidant Activities

Under the hypothesis that cardioprotective agents might benefit from synergism between antiarrhythmic activity and antioxidant properties, a small series of mexiletine analogues were coupled with the 2,2,5,5-tetramethylpyrroline moiety, known for its antioxidant effect, in order to obtain dual-acting drugs potentially useful in the protection of the heart against post-ischemic reperfusion injury. The pyrroline derivatives reported herein were found to be more potent as antiarrhythmic agents than mexiletine and displayed antioxidant activity. The most interesting tetramethylpyrroline congener, a tert-butyl-substituted analogue, was at least 100 times more active as an antiarrhythmic than mexiletine.     

Acid cleaning and passivation of power plant condensers and desalination plants

Experiences of acid cleaning and passivation treatments of copper alloy tubes are described. The suitability of corrosion monitoring to follow each step of such operation is demonstrated.     

Turing's Rules for the Imitation Game

In the 1950s, Alan Turing proposed his influential test for machine intelligence, which involved a teletyped dialogue between a human player, a machine, and an interrogator. Two readings of Turing's rules for the test have been given. According to the standard reading of Turing's words, the goal of the interrogator was to discover which was the human being and which was the machine, while the goal of the machine was to be indistinguishable from a human being. According to the literal reading, the goal of the machine was to simulate a man imitating a woman, while the interrogator – unaware of the real purpose of the test – was attempting to determine which of the two contestants was the woman and which was the man. The present work offers a study of Turing's rules for the test in the context of his advocated purpose and his other texts. The conclusion is that there are several independent and mutually reinforcing lines of evidence that support the standard reading, while fitting the literal reading in Turing's work faces severe interpretative difficulties. So, the controversy over Turing's rules should be settled in favor of the standard reading.     

Chemical synthesis and sintering behaviour of highly dispersed W/Cu composite powders

The paper reports the preparation of W/Cu composite powders by a wet process based on the reduction of selected copper precursors in ethylene glycol and in the presence of tungsten powders. Reactions were performed in different conditions of temperature, time and concentration of the copper precursor. Two different Cu compounds, Cu(AcO)₂·H₂O and CuO (coarse or fine) and two W powders (coarse or fine) were used. The reaction yields ranged from 75% to 98%. Dense bodies (up to 97% fractional density) with highly homogeneous microstructure as well as high electrical conductivity (up to 41% IACS) were obtained by sintering W/Cu powders at 1350 °C.     

Zirconia primers for corrosion resistant coatings

The recent restriction in the use of chromium VI gave a new impulse in the field of anti-corrosion treatment for an alternative solution.A promising route seems to be the deposition of a thin ceramic layer on the metallic surface. In this study, four zirconia primers have been deposited on 1050 aluminium sheets by sol-gel process. Sol preparation was obtained starting from two different precursors and two curing temperatures were tested.Surface microstructure and chemical composition were determined by AFM and XPS for all samples. Electrochemical Noise Analysis (ENA) was used in Harrison's solution to evaluate the corrosion resistant features of the samples. Tests have been also performed on samples protected by polyester topcoat deposited on the aforesaid primers.AFM analysis revealed that, for all the samples, covering and structure of the coating were uniform. XPS depth profiling allowed concluding that film thickness was in the range from 18 to 30 nm and that chemical composition was constant through primer thickness.Corrosion tests demonstrated that zirconia primers showed good performances in terms of corrosion resistance, comparable to chromate and fluotitanate layers industrially prepared.Topcoated samples gave an optimal corrosion resistance.     

Autosomal dominant medullary cystic disease: a disorder with variable clinical pictures and exclusion of linkage with the NPH1 locus

BACKGROUND: The nephronophthisis-medullary cystic disease (NPH/MCD) complex represents a heterogeneous group of hereditary tubulointerstitial nephritis. The most common variant is juvenile recessive NPH, for which a gene locus (NPH1) has been mapped on chromosome 2q13. MCD is a less common dominant condition usually recognized later in life, which resembles NPH in many aspects, still presenting remarkable clinical differences. Nothing is known about the chromosome locus of MCD. METHODS: Five MCD families were studied. Diagnosis was made by inference from family history, type of inheritance, clinical signs and histology. Multipoint linkage analysis was performed by markers D2S293, D2S340 and D2S160 spanning the entire NPH1 locus. RESULTS: Diagnosis of MCD was made in 28 affected members (16 males; 12 females), belonging to five families. Histological diagnosis was available in 10 patients; clinical diagnosis in 11; seven deceased relatives had diagnosis of chronic nephritis. The age at diagnosis ranged from 8 to 65 years. Renal medullary cysts were found in a minority of patients. In family 1, the disease was associated with hyperuricaemia and gouty arthritis. Progression of renal disease presented intra- and extra-family variability with members of the same family showing mild elevation of creatinine or terminal renal failure. The NPH1 locus associated to recessive NPH was excluded from linkage to the dominant MCD. CONCLUSIONS: MCD might be more common than previously assumed. Variability in clinical presentation and absence of histopathological hallmarks contribute to make the diagnosis uncommon. The most remarkable clinical difference with NPH is the age of onset in some kindreds and a delayed progression towards renal failure. The exclusion of linkage to the NPH1 locus suggests the existence of an MCD responsible locus, still to be mapped.     

Effect of surface modification on NO2 sensing properties of SnO2 varistor-type sensors

NO₂ sensing properties of SnO₂-based varistor-type sensors have been investigated in the temperature range of 400-650°C and in the NO₂ concentration range of 15–30 ppm. Pure SnO₂ exhibited a weak nonlinear I–V characteristic in air, but clear nonlinearity in NO₂ at 450°C. The breakdown voltage of SnO₂ shifted to a high electric field upon exposure to NO₂ and the magnitude of the shift was well correlated with NO₂ concentration. Thus, SnO₂ exhibited some sensitivity to NO₂ as a varistor-type sensor. When SnO₂ particles coated with a SiO₂ thin film were used as a raw material for fabricating a varistor, the breakdown voltage in air was approximately the double that of pure SnO₂ and the sensitivity to 15 ppm NO₂ was enhanced slightly. However, the sensitivity to 30 ppm NO₂ decreased. The Cr₂O₃-loading on SnO₂ also led to an increase in the breakdown voltage in air, but the Cr₂O₃ addition was not effective for promoting the NO₂ sensitivity under the present experimental conditions.     

A crevice corrosion study by Electrochemical Noise Analysis

The use of the Electrochemical Noise Analysis (ENA) for the evaluation of crevice corrosion is illustrated in the case of AISI 430 stainless steel in 3% sodium chloride. A crevice former was used in order to induce a crevice corrosion attack. Current and potential noise signals were simultaneously recorded allowing the determination of the noise resistance (R_n). ENA was able to detect the four stages mechanism of crevice corrosion. The comparison of R_n with the Polarization Resistance (R_p) determined by Electrochemical Impedance Spectroscopy (EIS) gave good agreement in particular during the initiation and propagation of the attack. The evaluation of the noise data in the frequency domain gave interesting results in particular in the evaluation of the roll‐off slopes in the Power Spectrum Density (PSD) plot that are correlated to the corrosive status. Finally a new analysis for noise data is shown. The application of spectral ratio discriminant function to noise data in the frequency domain, permits to deduce the best sampling frequency and sampling duration for ENA acquisition, able to discriminate between two different situations.     

Tomographic inversion of ocean bottom seismograph (OBS) data: Problems and solutions applied to the NW Svalbard Hydratech data set

The paper is aimed at discussing some problems that may arise in the tomographic inversion of data acquired with particular geometries, as vertical seismic profiles (VSP) or implying the use of Ocean Bottom Seismographs (OBS), and presenting the solutions used to solve them. One problem is due to the limited number of sensors (that may be even a single one) and of their sparseness. This affects the information distribution that is concentrated in the vicinity of each sensor. This fact, together with the second problem, i.e. the strong asymmetry of the ray path, may decrease the reliability of the inversion.Two procedures for irregular adaptive gridding of the reflecting interfaces and single ray datuming are proposed as possible solutions to overcome these obstacles, while obtaining a reliable and highly resolved velocity model in depth: the relative procedures are tested through synthetic models and on real data.