A DNA-Encoded Chemical Library Based on Peptide Macrocycles

The synthesis and characterization of a novel DNA-encoded library of macrocyclic peptide derivatives are described; the macrocycles are based on three sets of proteinogenic and non-proteinogenic amino acid building blocks and featuring the use of copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction for ring closure. The library (termed YO-DEL) which contains 1 254 838 compounds, was encoded with DNA in single-stranded format and was screened against target proteins of interest using affinity capture procedures and photocrosslinking. YO-DEL selections yielded specific binders against serum albumins, carbonic anhydrases and NKp46, a marker of activated Natural Killer cells.     

Synthesis,Structure, Solid-State NMR Spectroscopy,and Electronic Structures of the Phosphidotrielates Li3AlP2 and Li3GaP2

The lithium phosphidoaluminate Li₉AlP₄ represents a promising new compound with a high lithium ion mobility. This triggered the search for new members in the family of lithium phosphidotrielates, and the novel compounds Li₃AlP₂ and Li₃GaP₂, obtained directly from the elements via ball milling and subsequent annealing, are reported here. It was unexpectedly found through band structure calculations that Li₃AlP₂ and Li₃GaP₂ are direct band gap semiconductors with band gaps of 3.1 and 2.8 eV, respectively. Rietveld analyses reveal that both compounds crystallize isotypically in the orthorhombic space group Cmce (no. 64) with lattice parameters of a=11.5138(2), b=11.7634(2) and c=5.8202(1) Å for Li₃AlP₂, and a=11.5839(2), b=11.7809(2) and c=5.8129(2) Å for Li₃GaP₂. The crystal structures feature TrP₄ (Tr=Al, Ga) corner- and edge-sharing tetrahedra, forming two-dimensional layers. The lithium atoms are located between and inside these layers. The crystal structures were confirmed by MAS-NMR spectroscopy.     

Impact of Climatic Conditions on the Resveratrol Concentration in Blend of Vitis vinifera L. cvs. Barbera and Croatina Grape Wines

The aim of this work was to investigate the effect of meteorological conditions on resveratrol concentration of red wines produced in Piacenza viticultural region (Italy). In this regard, six representative estates producing Colli Piacentini Gutturnio DOC (a blend of V. vinifera L. cvs. Barbera and Croatina) vintage wines were analysed for trans- and cis-resveratrol over an 8-year period (1998–2005). Grapes were taken from the same vineyard in each estate by using the same enological practices over the entire investigated period. The meteorological conditions corresponding to the production areas were recorded, and bioclimatic indices were calculated as well. Overall, cis-resveratrol concentration was negatively correlated to Huglin index and August mean temperature, whilst positive correlation coefficients were found when considering the Selianinov index and the rainfall of September.     

Dissipative Dynamic Covalent Chemistry (DDCvC) Based on the Transimination Reaction

This work reports that the composition of a dynamic library (DL) of interconverting imines can be controlled over time in a dissipative fashion by the addition of an activated carboxylic acid used as a chemical fuel. When the fuel is added to the DL, which is initially under thermodynamic equilibrium, the composition of the mixture dramatically changes and a new, dissipative (out of equilibrium) state is reached that persists until fuel exhaustion. Thus, a transient dissipative dynamic library (DDL) is generated that, eventually, reverts back to the initial DL when the fuel is consumed, closing a DL→DDL→DL cycle. The larger the amount of added fuel, the longer the time spent by the system in the DDL state. The transimination reaction is shown to be an optimal candidate for the realization of a dissipative dynamic covalent chemistry (DDCvC).     

SiO2-Coated ZnO Nanoflakes Decorated with Ag Nanoparticles for Photocatalytic Water Oxidation

Many strategies have been adopted to improve the photoinduced features of zinc oxide nanostructures for different application fields. In this work, zinc oxide has been synthesised and decorated by plasmonic metal nanoparticles to enhance its photocatalytic activity in the visible range. Furthermore, an insulating layer of SiO₂ has been grown between the surface of zinc oxide nanoflakes and silver nanoparticles. A synthetic procedure that allows the accurate modulation of the insulating layer thickness in the range 5–40 nm has been developed. Evidences highlight the crucial role of the SiO₂ layer in dramatically increasing photocatalytic water oxidation promoted by the nanostructure under both UV and visible illumination. An ideal thickness value of about 10 nm has been demonstrated to guarantee the plasmon-induced resonance energy-transfer process and to quench the Förster resonance energy-transfer mechanism; thus, optimising the local surface plasmon resonance effect and water oxidation properties.     

Error diffusion on simplices: The structure of bounded invariant tiles

This is a companion paper to Adleret al. (in press, 2015). There, we proved the existence of an absorbing invariant tile for the Error Diffusion dynamics on an acute simplex when the input is constant and “ergodic” and we discuss the geometry of this tile. Under the same assumptions we prove here that said invariant tile (a fundamental set of the lattice generated by the vertices of the simplex) which is a finite union of polytopes have the property that any union of the intersections of the tile with the Voronoï regions of the vertices is a tile for a different, explicitly defined lattice.     

Impact of rock fabric,thermal behavior,and carbonate decomposition kinetics on quicklime industrial production and slaking reactivity

This paper deals with thermal analyses, burning trials and reactivity tests on 15 carbonate rocks, i.e., pure and impure carbonates, mud-supported and grain-supported limestones, crystalline marbles, and dolomites, used for the production of different lime products in industrial vertical shaft kilns worldwide. In particular, thermogravimetric and differential thermogravimetric analysis (TG–DTG) on massive (80–120 g) fine-grained (< 3.35 mm) samples allowed the extrapolation of the Arrhenius kinetic parameters, i.e., the (apparent) activation energy (E_a) and the pre-exponential or frequency factor (A). Other calcination parameters, i.e., the duration time, starting and ending calcination times and temperatures, and peaks of maximum calcination rate were also extrapolated in order to enhance their relationships with quicklime reactivity. Moreover, thermal analyses (TG–DTG–DTA) were repeated on powders (90 mg) using a more accurate analyzer to compare results. The study is completed by a thorough chemical–physical and mineralogical–petrographic characterization of carbonate rocks and derived burnt products. Results pointed out that medium-to-coarse crystalline materials, i.e., grain-supported limestones, diagenetic dolomites, and granoblastic marbles presented the highest activation energy, burnability and slaking reactivity. Conversely, microcrystalline carbonates with the highest micrite-to-sparite ratio, i.e., mud-supported limestones, and impure carbonates, enriched in quartz, clay minerals, and other subordinated non-carbonate impurities, presented the lowest activation energy, burnability, and slaking reactivity. This study also investigated the effect of BET-specific surface area and real density, depending on specific sintering tendency, on quicklime reactivity. Results from this multidisciplinary research activity put further constraints on carbonate rocks calcination kinetics and their suitability in the lime industry.

     

A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles

A straightforward approach to new polycyclic heterocycles, 1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-ones, is presented. It is based on the ZnCl₂-promoted deprotective 6-endo-dig heterocyclization of N-Boc-2-alkynylbenzimidazoles under mild conditions (CH₂Cl₂, 40 °C for 3 h). The zinc center plays a dual role, as it promotes Boc deprotection (with formation of the tert-butyl carbocation, which can be trapped by substrates bearing a nucleophilic group) and activates the triple bond toward intramolecular nucleophilic attack by the carbamate group. The structure of representative products has been confirmed by X-ray diffraction analysis.     

Blow-up and global existence for the porous medium equation with reaction on a class of Cartan–Hadamard manifolds

We consider the porous medium equation with power-type reaction terms $u^p$ on negatively curved Riemannian manifolds, and solutions corresponding to bounded, nonnegative and compactly supported data. If $p>m$, small data give rise to global-in-time solutions while solutions associated to large data blow up in finite time. If $p<m$, large data blow up at worst in infinite time, and under the stronger restriction $p\in (1,(1+m)/2]$ all data give rise to solutions existing globally in time, whereas solutions corresponding to large data blow up in infinite time. The results are in several aspects significantly different from the Euclidean ones, as has to be expected since negative curvature is known to give rise to faster diffusion properties of the porous medium equation.