Ionic Liquid Lignosulfonate: Dispersant and Binder for Preparation of Biocomposite Materials

Ionic liquid lignins are prepared from sodium lignosulfonate by a cation exchange reaction and display glass transition temperatures as low as ?13 °C. Diethyleneglycol‐functionalized protic cations inhibit lignin aggregation to produce a free‐flowing “ionic liquid lignin”, despite it being a high‐molecular‐weight polyelectrolyte. Through this approach, the properties of both lignin and ionic liquids are combined to create a dispersant and binder for cellulose+gluten mixtures to produce small microphases. Biocomposite testing pieces are produced by hot‐pressing this mixture, yielding a material with fewer defects and improved toughness in comparison to other lignins. The use of unmodified lignosulfonate, acetylated lignosulfonate, or free ionic liquid for similar materials production yields poorer substances because of their inability to maximize interfacial contact and complexation with cellulose and proteins.     

Mixing of electronic states in pentacene adsorption on copper

By combining experimental and theoretical approaches, we study the adsorption of pentacene on copper as a model for the coupling between aromatic molecules and metal surfaces. Our results for the interface electronic structure are not compatible with a purely physisorption picture, which is conventionally employed for such systems. Nay, we demonstrate electronic mixing between molecular orbitals and metal electronic states.     

Gas-Phase Lithium Cation Basicity: Revisiting the High Basicity Range by Experiment and Theory

According to high level calculations, the upper part of the previously published FT-ICR lithium cation basicity (LiCB at 373 K) scale appeared to be biased by a systematic downward shift. The purpose of this work was to determine the source of this systematic difference. New experimental LiCB values at 373 K have been measured for 31 ligands by proton-transfer equilibrium techniques, ranging from tetrahydrofuran (137.2 kJ mol^?1) to 1,2-dimethoxyethane (202.7 kJ mol^?1). The relative basicities (ΔLiCB) were included in a single self-consistent ladder anchored to the absolute LiCB value of pyridine (146.7 kJ mol^?1). This new LiCB scale exhibits a good agreement with theoretical values obtained at G2(MP2) level. By means of kinetic modeling, it was also shown that equilibrium measurements can be performed in spite of the formation of Li⁺ bound dimers. The key feature for achieving accurate equilibrium measurements is the ion trapping time. The potential causes of discrepancies between the new data and previous experimental measurements were analyzed. It was concluded that the disagreement essentially finds its origin in the estimation of temperature and the calibration of Cook’s kinetic method. Graphical Abstract

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Easy Access to Ni3N– and Ni–Carbon Nanocomposite Catalysts

In the search for alternative materials to current expensive catalysts, Ni has been addressed as one of the most promising and, on this trail, its corresponding nitride. However, nickel nitride is a thermally unstable compound, and therefore not easy to prepare especially as nanoparticles. In the present work, a sol–gel‐based process (the urea glass route) is applied to prepare well‐defined and homogeneous Ni₃N and Ni nanoparticles. In both cases, the prepared crystalline nanoparticles (～25 nm) are dispersed in a carbon matrix forming interesting Ni₃N‐ and Ni‐based composites. These nanocomposites were characterised by means of several techniques, such as XRD, HR‐TEM, EELS, and the reaction mechanism was investigated by TGA and IR and herein discussed. The catalytic activity of Ni₃N is investigated for the first time, to the best of our knowledge, for hydrogenation reactions involving H₂, and here compared to the one of Ni. Both materials show good catalytic activities but, interestingly, give a different selectivity between different functional groups (namely, nitro, alkene and nitrile groups).     

Enantioselective reduction and deracemisation using the non-conventional yeast Pichia glucozyma in water/organic solvent biphasic systems: preparation of (S)-1,2-diaryl-2-hydroxyethanones (benzoins)

Water/organic solvent two-liquid-phase systems have been successfully applied in the synthesis of enantiomerically pure (S)-benzoin through two different methodologies catalysed by whole cells from the non-conventional yeast Pichia glucozyma: the stereoselective monoreduction of benzil and the deracemisation of benzoin. The presence of the organic solvent influences the redox systems implied in the reactions, avoiding the formation of the corresponding diols, increasing the enantioselectivity and allowing the easy isolation of the products in high yields and excellent enantiomeric excesses. The use of both strategies has been extended to the preparation of different chiral benzoin derivatives.     

Subcellular detection and localization of the drug transporter P-glycoprotein in cultured tumor cells

In vitro studies on the cellular location of P-glycoprotein (Pgp) are reported with the aim to clarify the relationship between its intracellular expression and the multidrug resistance (MDR) level of tumor cells. Pgp was found abnormally expressed on the plasma membrane of tumor cells with "classical" MDR phenotype. However, Pgp was also often detected on the nuclear envelope and on the membrane of cytoplasmic organelles. The hypothesis that this drug pump maintains a transport function when located in these compartments, is still under debating. Our results, together with those obtained by other researchers, demonstrate that cytoplasmic Pgp regulates the intracellular traffic of drugs so that they are no more able to reach their cellular targets. In particular, we revealed that in MDR breast cancer cells (MCF-7) a significant level of Pgp was expressed in the Golgi apparatus. A similar result was found in human melanoma cell lines, which never undergone cytotoxic drug treatment and did not express the transporter molecule on the plasma membrane. A strict relationship between intracellular Pgp and intrinsic resistance was demonstrated in a human colon carcinoma (LoVo) clone, which did not express the drug transporter on the plasma membrane. Finally, a structural and functional association between Pgp and ERM proteins has been discovered in drug-resistant human T- lymphobastoid cells (CEM-VBL 100). Our findings strongly suggest a pivotal role of the intracytoplasmic Pgp in the transport of drugs into cytoplasmic vesicles, thus actively contributing to their sequestration and transport outwards the cells. Thus, intracellular Pgp seems to represent a complementary protective mechanism of tumor cells against cytotoxic agents.     

Quenching and hardening in the transverse quasi-elastic peak

We study in the RPA framework the collective response of symmetric, infinite nuclear matter to a spin-isospin sensitive probe with both σ · q and σ × q couplings. The two responses, similar in the low-q region, differ markedly for moderate momenta (?1 fm^?1). Indeed the collective effect manifests itself quite differently in the two responses; whereas the longitudinal one displays a softening and an enhancement (due to the attractive character of the associated particle-hole force), the transverse response is quenched and hardened with respect to the free Fermi gas. The existing experimental data, which we analyze, are compatible with our results. We also explore the total strengths and find that for repulsive forces they are appreciably reduced by the RPA correlations. A large part of this quenching comes from the Δ-excitation (LLEE effect), but some reduction is still present even when the nucleonic degrees of freedom are neglected. This illustrates a violation of strength conservation brought about by the RPA correlations in the spin-isospin channel.