De Morgan Heyting algebras satisfying the identity xn(′*) ≈ x(n+1)(′*)

In this paper we investigate the sequence of subvarieties $ {\mathcal {SDH}_n} $of De Morgan Heyting algebras characterized by the identity x^n(′*) ≈ x^(n+1)(′*). We obtain necessary and sufficient conditions for a De Morgan Heyting algebra to be in $ {\mathcal {SDH}_1} $ by means of its space of prime filters, and we characterize subdirectly irreducible and simple algebras in $ {\mathcal {SDH}_1} $. We extend these results for finite algebras in the general case $ {\mathcal {SDH}_n} $. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

How do Pseudoenantiomers Structurally Differ in the Gas Phase? An IR/UV Spectroscopy Study of Jet‐Cooled Hydroquinine and Hydroquinidine

The gas‐phase structures of the cinchona alkaloids, hydroquinine and its pseudoenantiomer hydroquinidine, are studied in a supersonic expansion by means of laser‐induced fluorescence and IR/UV double‐resonance spectroscopy. Vibrational spectroscopy combined with density functional calculations show that the conformational properties of the two pseudoenantiomers are identical. In both cases, they exist in two isoenergetic forms, with similar IR spectra. Both conformers are similar to the most stable cis‐γ‐open form of quinine; they differ from each other by the position of the ethyl substituent attached to the quinuclidine ring. Further differences between the two conformers are observed in the laser‐induced fluorescence spectrum. The first electronic transition is characterized by time‐dependent density functional theory and RI‐cc2 calculations, and is of ππ* nature. The results described here emphasize the role of the ethyl substituent in the structural differences between pseudoenantiomers of cinchona alkaloids.     

Different approaches to the study of chelating agents for iron and aluminium overload pathologies

Our objective is to illustrate the activity of the groups operating in Italy involved in identification and study of new chelating agents, mainly intended for treatment of human pathology correlated with metal overload. The objective of “chelation therapy” is removal of toxic metal ions from the human body or attenuation of their toxicity by transforming them into less toxic compounds or by dislocating them from the site at which they exert a toxic action. Because most of this research activity is related to chelating agents for iron and aluminium, diseases related to these two metal ions are briefly treated. Iron overload is the most common metal toxicity disease worldwide. The toxicity of aluminium in dialysis patients was a serious problem for haemodialysis units in the seventies and eighties of the last century. In particular, this review focuses on research performed by the group at Cagliari and Ferrara, and by that at Padova. The former is studying, above all, bisphosphonate and kojic acid derivatives, and the latter is investigating 3,4-hydroxypyridinecarboxylic acids with differently substituted pyridinic rings.

Conditions for calibration of an isothermal titration calorimeter using chemical reactions

The reaction of protonation of 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) is a suitable one for the calibration of isothermal titration calorimeter (ITC), providing that experimental conditions are appropriately chosen. The conditions and methods for handling experimental data from a nanowatt-ITC are discussed. Also, the binding of Ba²⁺ to 18-Crown-6 is successfully used to check the accuracy and precision of the chemical calibration performed with TRIS. This latter reaction has the additional advantage that the data can also be used for a check on the determination of the value of a binding constant. The anomaly of the first injection in ITC is analyzed and, by combining calorimetric and spectroscopic measurements, it is shown that it mainly results from a backlash effect of the syringe plunger rather than from a diffusion effect.     

Collisions of Vortex Filament Pairs

We consider the problem of collisions of vortex filaments for a model introduced by Klein et al. (J Fluid Mech 288:201–248, 1995) and Zakharov (Sov Phys Usp 31(7):672–674, 1988, Lect. Notes Phys 536:369–385, 1999) to describe the interaction of almost parallel vortex filaments in three-dimensional fluids. Since the results of Crow (AIAA J 8:2172–2179, 1970) examples of collisions are searched as perturbations of antiparallel translating pairs of filaments, with initial perturbations related to the unstable mode of the linearized problem; most results are numerical calculations. In this article, we first consider a related model for the evolution of pairs of filaments, and we display another type of initial perturbation leading to collision in finite time. Moreover, we give numerical evidence that it also leads to collision through the initial model. We finally study the self-similar solutions of the model.     

Computational framework for longevity risk management

Longevity risk threatens the financial stability of private and government sponsored defined benefit pension systems as well as social security schemes, in an environment already characterized by persistent low interest rates and heightened financial uncertainty. The mortality experience of countries in the industrialized world would suggest a substantial age-time interaction, with the two dominant trends affecting different age groups at different times. From a statistical point of view, this indicates a dependence structure. It is observed that mortality improvements are similar for individuals of contiguous ages (Wills and Sherris, Integrating financial and demographic longevity risk models: an Australian model for financial applications, Discussion Paper PI-0817, 2008). Moreover, considering the dataset by single ages, the correlations between the residuals for adjacent age groups tend to be high (as noted in Denton et al., J Population Econ 18:203–227, 2005). This suggests that there is value in exploring the dependence structure, also across time, in other words the inter-period correlation. In this research, we focus on the projections of mortality rates, contravening the most commonly encountered dependence property which is the “lack of dependence” (Denuit et al., Actuarial theory for dependent risks: measures. Orders and models, Wiley, New York, 2005). By taking into account the presence of dependence across age and time which leads to systematic over-estimation or under-estimation of uncertainty in the estimates (Liu and Braun, J Probability Stat, 813583:15, 2010), the paper analyzes a tailor-made bootstrap methodology for capturing the spatial dependence in deriving confidence intervals for mortality projection rates. We propose a method which leads to a prudent measure of longevity risk, avoiding the structural incompleteness of the ordinary simulation bootstrap methodology which involves the assumption of independence.     

N-Polybenzylated alicyclic 1,2-diamines: cytotoxicity and G1 phase arrest in cancer cell line

Cytotoxicity in the \(\upmu \hbox {M}\) range was observed in cancer cell lines treated with N,N, \(N^{\prime }\!,\!N^{\prime }\) -tetrabenzyl-4,5-diamino-2-cyclopentenone. Cell cycle analysis on HeLa cells showed a clear G1 phase arrest. A preliminary SAR on structural analogs was performed in order to identify the pharmacophores.     

Chemical Investigation on Various Aromatic Compounds Polymerization in Low Pressure Helium Plasma

Remarkable properties of plasma polymer films are greatly dependent not only on the chemical structure of precursor but also on the reactor design and the deposition conditions. In many industrial applications it is a challenge to control the plasma polymer structure. In this paper we investigate the chemical transformation of various aromatic compounds, such as activation and fragmentation of substituent-part, aromatic ring opening, during plasma polymerization process. Polymerized films are deposited in a low-frequency capacitively coupled plasma-enhanced chemical vapour deposition reactor, working at low pressure. The chemical composition of plasma-polymerized films is elucidated by Fourier-transform infrared spectroscopy, solid-state carbon-13 nuclear magnetic resonance spectroscopy, and X-ray photoelectron spectroscopy. Based on spectroscopic measurements, the intermediary reactions during film growth may be presumed.     

Determination of fluoroquinolones in bovine milk samples using a pipette‐tip SPE step based on multiwalled carbon nanotubes prior to CE separation

A simple CE–UV method was developed for the simultaneous determination of ciprofloxacin, norfloxacin, and ofloxacin in milk samples. The optimum separation was obtained using a 20 mM ammonium dihydrogenphosphate solution with 2 mM cetyltrimethylammonium bromide at pH 3.0 as the BGE. Satisfactory resolution for structurally very similar analytes, like norfloxacin and ciprofloxacin, was achieved without including any organic solvent. Milk samples were prepared using a simple/extraction procedure based on acidic protein precipitation followed by an SPE step using only 5 mg of multiwalled carbon nanotubes as the sorbent material. The LODs for the three compounds were between 7.5 and 11.6 μg/L and the RSDs for the peak areas were between 2.6 and 4.9%. The complete method was applied to spiked real milk samples with satisfactory recoveries for all analytes (84–106%).