Photocatalytic transformations of aminopyrimidines on TiO2 in aqueous solution

In this paper, the effect of the presence of humidity and molecular oxygen on the low temperature oxidation of carbon monoxide on a Co₃O₄ powder surface was studied. The interaction between the probe molecules and the Co₃O₄ surface was investigated by means of diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and quadrupolar mass spectrometry (QMS).

Carbon monoxide interacts with the Co₃O₄ surface and is converted to carbon dioxide at rather low temperature (T≥323 K); the formation of carbonate species is also evident. The reactivity of Co₃O₄ is strongly depressed by humidity: as a matter of fact, in steam conditions carbon monoxide oxidation is significant at temperatures higher than 523 K. Moreover, the formation of carbonate species is more evident than in dry conditions. The Co₃O₄ powder surface interacts with oxygen molecules at T≥323 K to originate several activated surface oxygen species. The activation with oxygen does not appear to facilitate significantly the formation of carbon dioxide.     

Pyridine adsorption reveals high-coordinated cationic centres at the surface of microcrystalline ZnO

The adsorption of pyridine at 300 K on microcrystalline ZnO has been investigated by FTIR spectroscopy. Besides an interaction by H-bonding with surface OH groups, evidence is found for the Lewis coordination of pyridine onto coordinatively unsaturated surface Zn²⁺ centres possessing a regular tetrahedral coordination, as well as onto some other surface Zn²⁺ centres, only slightly uncoordinated. The creation at the surface of the ZnO of cationic centres with an anomalous coordination higher than 4 (quasi-octahedral) is thus postulated. No such high-coordinated Zn²⁺ centres seem to form to an appreciable extent when ZnO is dispersed (at least at up to a 3% weight level) at the surface of other microcrystalline oxides such as, for instance, TiO₂.     

H2S gas treatment with Thiobacillus Ferrooxidans – process performance and stability

The present paper deals with a novel hydrogen sulphide abatement process applying a combined chemical-biological process. The authors already dealt with this subject in the paper “Biotechnological H₂S gas treatment with Thiobacillus ferrooxidans” [1], previously published in Chemical Engineering and Technology. This study, in particular, deals with over all process test runs in a laboratory scale plant with a single-stage immobilised biomass reactor.     

SIMPLIFICATION OF CURRENT-MODE MULTIVALUED CMOS CIRCUITS

This paper proposes a simplification method for realization of current-mode multivalued CMOS circuits. The key of this method is to find a cover on the K-map for a given multivalued function, which fits to the realization of current-mode CMOS circuits. The design example shows that the design presented in this paper is better than the design proposed by G. W. Dueck et al. (1987).     

Tensile mechanical behavior of linear high‐density polyethylenes modified with organic peroxide

The molecular structure of several high‐density polyethylenes of different molecular weights and vinyl contents was modified without altering their thermoplastic character using an organic peroxide. Chain linking was the main chemical event that occurred during the modification process. Samples of these polymers were crystallized from the melt, generating materials with different morphologies. Two crystallization procedures were followed: slow cooling and quenching. The density and crystallinity of the polymers were found to be slightly dependent on the molecular structures generated by the modification process. Tensile tests were performed at room temperature to evaluate the mechanical behavior of the polymers. The mechanical response of some of the slowly cooled samples changed from brittle to ductile when increasing concentrations of peroxide were added to the formulation. All the quenched samples displayed ductile behavior. The elastic modulus and yield stress were found to increase linearly with the crystallinity of the polymers independently of the molecular structure generated by the modification process. The molecular weight of the modified polymers appears to be the main structural property that influences the draw ratio after break and the ultimate tensile stress of the samples. The draw ratio diminishes, while the ultimate tensile stress increases with the molecular weight of the polymers, irrespective of the evolution of other molecular parameters.     

Functional Characterization of Two Novel Mutations in SCN5A Associated with Brugada Syndrome Identified in Italian Patients

Background. Brugada syndrome (BrS) is an autosomal dominantly inherited cardiac disease characterized by “coved type” ST-segment elevation in the right precordial leads, high susceptibility to ventricular arrhythmia and a family history of sudden cardiac death. The SCN5A gene, encoding for the cardiac voltage-gated sodium channel Nav1.5, accounts for ~20–30% of BrS cases and is considered clinically relevant. Methods. Here, we describe the clinical findings of two Italian families affected by BrS and provide the functional characterization of two novel SCN5A mutations, the missense variant Pro1310Leu and the in-frame insertion Gly1687_Ile1688insGlyArg. Results. Despite being clinically different, both patients have a family history of sudden cardiac death and had history of arrhythmic events. The Pro1310Leu mutation significantly reduced peak sodium current density without affecting channel membrane localization. Changes in the gating properties of expressed Pro1310Leu channel likely account for the loss-of-function phenotype. On the other hand, Gly1687_Ile1688insGlyArg channel, identified in a female patient, yielded a nearly undetectable sodium current. Following mexiletine incubation, the Gly1687_Ile1688insGlyArg channel showed detectable, albeit very small, currents and biophysical properties similar to those of the Nav1.5 wild-type channel. Conclusions. Overall, our results suggest that the degree of loss-of-function shown by the two Nav1.5 mutant channels correlates with the aggressive clinical phenotype of the two probands. This genotype-phenotype correlation is fundamental to set out appropriate therapeutical intervention.     

A way to decylamine-stabilized gold nanoparticles of tailored sizes tuning their growth in solution

Acetone solvated Au nanoparticles (Au NPs) were prepared by Metal Vapour Synthesis (MVS) co-condensing Au and acetone vapours. Nanoparticles growth was quenched at different times by using decylamine (DA) as stabilizer and DA-stabilized Au NPs were characterized by UV-Vis, NMR DOSY and HRTEM techniques. The dependence of metal clustering processes on gold concentration was investigated.     

Reaction of diphenylpicrylhydrazyl (DPPH) with antioxidants in presence of poly(epsilon-caprolactone)/ poly(N-vinyl-2-pyrrolidone) block copolymer nanoaggregates

The reaction of antioxidants with 2,2-diphenyl-l-picrylhydrazyl (DPPH) has been studied employing both, ethanol and nano aggregates biodegradable block copolymers (BBC) in aqueous solution, as reaction media. Gallate derivatives with different chain lengths (gallic acid, methyl, propyl and octyl gallate) were used as antioxidants model, and BBC containing a central section of poly-epsilon-caprolactone (PCL) and three arms of poly-vinylpirrolidone (PVP) were used to originate nano aggregates in aqueous solution. The course of the reaction was followed by the changes of the DPPH absorption band at 517 nm. In ethanol, using an excess of antioxidants, DPPH was consumed completely by all gallate derivatives. Nevertheless, when the same reaction was carried out in aqueous nano aggregates of BBC, only a partial consumption of DPPH was observed, suggesting the occurrence of a complex reaction mechanism.     

Interaction study of indigo carmine with albumin and dextran by NMR relaxation

In this study, the interaction processes between a dye (indigo carmine) and two different macromolecular models were studied with the aim to obtain physical-chemistry information about the dyeing of textiles. Two macromolecules, albumin and dextran (DX), were chosen to simulate wool and cotton fibers during the coloration procedure in water. Proton NMR selective and non-selective spin–lattice relaxation rate measurements were used to monitor the strength of the overall complexation behavior of indigo carmine toward albumin or DX. The affinity index, a quantitative parameter related to the strength of the ligand–macromolecule interaction, was determined from selective spin–lattice relaxation rate enhancements due to the bound ligand molar fraction. Moreover, this approach allowed the calculation of the equilibrium constant of the complex formation (K) between the dye and macromolecular models. NMR data suggested a higher indigo carmine–albumin complex thermodynamic stability with respect to the indigo carmine–DX adduct. These results indicate a stronger persistence of the dyeing process in wool with respect to cotton fibers, in agreement with literature data.