Characterization of formate complexes formed as corrosion products on copper by raman spectroscopy

Different copper formate complexes formed on the surface of metallic copper have been studied by Raman spectroscopy. Their Raman spectra have been correlated with the dehydrated copper formate, the copper formate dihydrate and the copper formate tetrahydrate. Experiments with deuterated formic acid reveal the influence of water molecules coordinated to the copper ion on the position of Raman bands of the formate ion.     

Synthesis of granulatimide bis-imide analogues

The synthesis of dipyrrolo[3,4-a:3,4-c]carbazole-1,3,4,6-tetraones, structurally related to granulatimide is reported. These compounds can be considered as granulatimide analogues in which a maleimide heterocycle replaces the imidazole moiety. The synthesis of pyridino[2,3-b]dipyrrolo[3,4-e:3,4-g]indole-1,3,4,6-tetraones is also reported. In these compounds, a 7-azaindole unit replaces the indole moiety present in the granulatimide and isogranulatimide structures.     

Influence of UVB,UVA and UVA1 irradiation on histamine release from human basophils and mast cells in vitro in the presence and absence of antioxidants

UV irradiation is widely used for the treatment of atopic eczema. In recent years, UVA1 phototherapy has gained increasing attention. This study analyzed the influence of different UV wavelengths--especially UVA1--on histamine release from human basophils and mast cells. The modulation of this parameter might be responsible for some of the therapeutic effects of UV irradiation. Enriched human basophils and human mast cells (HMC1 cell line) were irradiated with increasing doses of UVB, UVA and UVA1 in vitro. After irradiation, different stimulants were added to induce histamine release. In additional experiments, basophils were preincubated with superoxide dismutase, ascorbate or trolox to study the role of antioxidants in the modulation of histamine release after UV irradiation. UVA and UVA1 significantly inhibited histamine release from basophils and mast cells. UVB only had an inhibitory effect on mast cells. Preincubation with superoxide dismutase and ascorbate did not influence the inhibitory effect of UVA1 on basophil histamine release, whereas trolox decreased significantly the histamine release from nonirradiated basophils.     

Finite factorization domains

An integral domain is a finite factorization domain if each nonzero element of has only finitely many divisors, up to associates. We show that a Noetherian domain is an FFD for each overring of that is a finitely generated -module, is finite. For local this is also equivalent to each being finite. We show that a one-dimensional local domain is an FFD either is finite or is a DVR.

     

Use of iridium oxide films as hydrogen gas evolution cathodes in aqueous media

Hydrous iridium oxide films are highly resistant to reduction under cathodic, hydrogen gas evolution, conditions in aqueous acid or base. Such behavior is not in agreement with simple thermodynamic (Pourbaix) data based on the assumption that the system behaves in a reversible manner. The barrier to reduction is attributed, as discussed earlier for RuO₂, to the involvement of high-energy intermediates (iridium atoms or microclusters of same) which can only be generated at unusually negative overpotential values evidently far into the hydrogen gas evolution region. Thermally prepared IrO₂/Ti electrodes are possible candidates for hydrogen gas evolution cathodes in water electrolysis cells; however, under extended operating conditions, the performance of these cathodes was found to deteriorate due to gradual shedding of the active oxide layer.     

Mechanism and kinetics of dithiobenzoate‐mediated RAFT polymerization. I. The current situation

Investigations into the kinetics and mechanism of dithiobenzoate‐mediated Reversible Addition–Fragmentation Chain Transfer (RAFT) polymerizations, which exhibit nonideal kinetic behavior, such as induction periods and rate retardation, are comprehensively reviewed. The appreciable uncertainty in the rate coefficients associated with the RAFT equilibrium is discussed and methods for obtaining RAFT‐specific rate coefficients are detailed. In addition, mechanistic studies are presented, which target the elucidation of the fundamental cause of rate retarding effects. The experimental and theoretical data existing in the literature are critically evaluated and apparent discrepancies between the results of different studies into the kinetics of RAFT polymerizations are discussed. Finally, recommendations for further work are given. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5809–5831, 2006     

Pegylated thermally responsive block copolymer micelles and nanogels via in situ RAFT aqueous dispersion polymerization

A very straightforward approach was developed to synthesize pegylated thermoresponsive core‐shell nanoparticles in a minimum of steps, directly in water. It is based on RAFT‐controlled radical crosslinking copolymerization of N,N‐diethylacrylamide (DEAAm) and N,N′‐methylene bisacrylamide (MBA) in aqueous dispersion polymerization. Because DEAAm is water‐soluble and poly(N,N‐diethylacrylamide) (PDEAAm) exhibits a lower critical solution temperature at 32 °C, the initial medium was homogeneous, whereas the polymer formed a separate phase at the reaction temperature. The first macroRAFT agent was a surface‐active trithiocarbonate based on a hydrophilic poly(ethylene oxide) block and a hydrophobic dodecyl chain. It was further extented with N,N‐dimethylacrylamide (DMAAm) to target macroRAFT agents with increasing chain length. All macroRAFT agents provided excellent control over the aqueous dispersion homopolymerization of DEAAm. When they were used in the radical crosslinking copolymerization of DEAAm and MBA, the stability and size of the resulting gel particles were found to depend strongly on the chain length of the macroRAFT agent, on the concentrations of both the monomer and the crosslinker, and on the process (one step or two steps). The best‐suited experimental conditions to reach thermosensitive hydrogels with nanometric size and well‐defined surface properties were determined. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2373–2390, 2009     

Dynamic Walrasian price equilibrium problem: evolutionary variational approach with sensitivity analysis

Many authors have been devoted to the study of the static general economic equilibrium problem regulated to Walras’ law (see e.g. Arrow and Debreu in Econometrica 22:265–290, 1954; Arrow and Hahn in General competitive analysis, 1991; Arrow et al. in Econometrica 27:82–109, 1959; Border in Fixed point theorems with application to economics and game theory, Cambridge University Press, Cambridge, 1985; Dafermos in Math Programm 46:391–402, 1990; Dafermos and Zhao in Oper Res Lett 10:396–376, 1991; Donato et al. in J Glob Optim, 2007; Hahn in Stability, North Holland, Amsterdam, 1982; Jofré et al. in Math Oper Res, 2007; Nagurney in Network economics—a variational inequality approach, Kluwer, Dordrecht, 1999; Nagurney and Zhao in Network formalism for pure exchange economic equilibria, World Scientific Press, Singapore, 1993; Walker in J Polit Econ 94(4), 1987; Walras in Elements d’Economique Politique Pure, Corbaz, Lausanne, Switzerland, 1874; Zhao in Variational inequalities in general equilibrium: analysis and computation, PhD thesis, Brown University, 1988; and their bibliography). The aim of this paper is to provide a first approach to a particular dynamic general economic equilibrium problem: a Walrasian price equilibrium problem when the data are time-dependent. The equilibrium conditions that describe this pure exchange economic model are expressed in terms of an evolutionary variational inequality, for which existence and sensitivity results are given. Moreover, our problem can be expressed in a common way to many other equilibrium problems.     

Quantitative determination of magnetic fields from iron particles of oblong form encapsulated by carbon nanotubes using electron holography

Using electron holography (interference electron microscopy) we have made measurements of the magnetic flux and magnetic field distribution around a carbon nanotube filled with iron. At the surface of the carbon nanotube, an iron particle with a radius of 30 nm and a length of 200 nm created a magnetic flux of 10⁻¹⁵ Wb (Weber) and a magnetic field of 0.3–0.4 T (Tesla). The theory developed in this work is constrained to the case of cylindrical symmetry of the investigated ferromagnetic particles, but, in general, such studies can be made for ferromagnetic particles of any shape.