Single-Directional Properties of Quasi-Monotone Operators

A large supply of quasi-monotone multivalued mappings with values in a weak* fragmentable dual Banach space is shown to be generically single-directional. This is of some interest in analysis of quasi-convex functions. The paper extends/strengthens some results of a recent paper by Aussel and Eberhard (Math Program 30, 2012).     

Visible-light photolysis of [FeCp(η6-toluene)][PF6] as a clean,convenient and general route to iron-vinylidene and iron-acetylide complexes

Visible-light photolysis of the cheap starting material [FeCp(η⁶-toluene)][PF₆] (Cpη⁵-C₅H₅) using a simple 100-W globe in the presence of diphenyldiphosphinoethane (dppe) and terminal alkynes cleanly yields the vinylidene complexes [FeCp(dppe)(CCHR)][PF₆] and, upon further deprotonation, the iron-alkynyl complexes; the reaction is extended to ferrocenylacetylene to yield a bimetallic complex.     

Modeling [FeFe] hydrogenase: Synthesis and protonation of a diiron dithiolate complex containing a phosphine-N-heterocyclic-carbene ligand

The ligand exchange reaction of I_Me-(CH₂)₂-PPh₂ (I_Me = 1-methyimidazol-2-ylidene) and the hexacarbonyl complex [{Fe₂{μ-S(CH₂)₃S}(CO)₆] (1) resulted in the formation of the chelated complex [{Fe₂{μ-S(CH₂)₃S}(CO)₄(I_Me-(CH₂)₂-PPh₂)] (2). The molecular structure of 2 was confirmed by spectroscopic and X-ray analyses. This complex catalyzes proton reduction. Low temperature NMR studies on the protonation of 2 revealed the formation of a terminal hydride intermediate.     

Cations Insertion in Molybdenum Cluster Compounds: Electronic Structure and Electrochemical Study Using Cavity Microelectrode

Owing to the high lability of cations in the three-dimensional framework of K_1+x Mo₁₂S₁₄ (0 ≤ x ≤ 1.6), first-principles calculations and electrochemical methods have been carried out to study the insertion of cations in the empty channels of this compound. The cavity microelectrode that is a suitable electrode for powder material analysis has been used in voltammetric experiments. Results obtained for Li⁺, Na⁺, Rb⁺, K⁺, Cs⁺ and NH₄ ⁺ cations are presented and discussed.     

Novel chemometric strategy based on the application of artificial neural networks to crossed mixture design for the improvement of recombinant protein production in continuous culture

The optimal blends of six compounds that should be present in culture media used in recombinant protein production were determined by means of artificial neural networks (ANN) coupled with crossed mixture experimental design. This combination constitutes a novel approach to develop a medium for cultivating genetically engineered mammalian cells. The compounds were collected in two mixtures of three elements each, and the experimental space was determined by a crossed mixture design. Empirical data from 51 experimental units were used in a multiresponse analysis to train artificial neural networks which satisfy different requirements, in order to define two new culture media (Medium 1 and Medium 2) to be used in a continuous biopharmaceutical production process. These media were tested in a bioreactor to produce a recombinant protein in CHO cells. Remarkably, for both predicted media all responses satisfied the predefined goals pursued during the analysis, except in the case of the specific growth rate (μ) observed for Medium 1. ANN analysis proved to be a suitable methodology to be used when dealing with complex experimental designs, as frequently occurs in the optimization of production processes in the biotechnology area. The present work is a new example of the use of ANN for the resolution of a complex, real life system, successfully employed in the context of a biopharmaceutical production process.     

Dissociation enthalpies and phase equilibrium for TBAB semi-clathrate hydrates of N<Subscript>2</Subscript>, CO<Subscript>2</Subscript>, N<Subscript>2</Subscript> + CO<Subscript>2</Subscript> and CH<Subscript>4</Subscript> + CO<Subscript>2</Subscript>

Tetra-n-butyl ammonium bromide (TBAB) semi-clathrate (sc) hydrates of gas are of prime importance in the secondary refrigeration domain and in the separation of gas molecules by molecular size. However, there is a scarcity of dissociation enthalpies under pressure of pure gases and gases mixtures for such systems. In addition, the phase equilibrium of TBAB sc hydrates of several pure gases is not well defined yet as a function of the TBAB concentration and as a function of the pressure. In this paper, dissociation enthalpies and the phase equilibrium of TBAB sc hydrates of gas have been investigated by differential scanning calorimetry (DSC) under pressure. Pure gases such as N₂ and CO₂ and gases mixtures such as N₂ +  CO₂ and CH₄ +  CO₂ were studied. To our knowledge, we present the first phase diagram of TBAB sc hydrates of N₂ for different pressures of gas in the TBAB concentration range from 0.170 to 0.350 wt. Enthalpies of dissociation of TBAB sc hydrates of pure gases and gases mixtures were determined as a function of the presssure for a compound with a congruent melting point whose hydration number corresponds to 26.     

Gold(I) Complexes of Phosphanyl Gallanes: From Interconverting to Separable Coordination Isomers

Gallant exchange : Upon coordination of phosphanyl gallane ligands to AuCl, both neutral and zwitterionic complexes coexist. NMR spectroscopy provides direct evidence for the transfer of the chloride between gold and gallium in diphosphanyl gallane. The introduction of a third phosphanyl buttress allows the separation and structural characterization of the two coordination isomers (see picture; Au yellow, P red, Cl green, Ga blue).

     

Optical deflection tomography with the phase-shifting schlieren

We present a new optical deflection tomography method that takes advantage of the phase-shifting schlieren. The reconstruction algorithm is based on filtered backprojection. The instrument is well adapted for three-dimensional imaging of spatially sparse objects exhibiting large refractive index variations. It achieves a 35 μm resolution with a 3 mm depth of field. Its performance is illustrated with a bundle of fibers immersed in a matching index solution.     

Photodissociation Rate Constants of New Light Sensitive Alkoxyamines

The photochemical properties of two new photocleavable alkoxyamines bearing a benzophenone‐derived chromophore were studied by electron spin resonance (ESR). The C O bond cleavage has been demonstrated and the photolysis rate constants (k_d) determined over a large range of light intensity through the monitoring of the nitroxide concentration in aerated conditions. The obtained kinetic data highlight for the first time the linear dependence of k_d on the light intensity for alkoxyamines: this should be a driving factor for nitroxide mediated radical photopolymerization (NMP²).