An Automatic Molecular Dispenser of Chloride

The combined activity of the 1.1.1‐cryptand and of a dicopper(II) bistren cryptate complex including chloride makes the Cl^? ion be continuously and slowly delivered to the solution, without any external intervention. The 1.1.1‐cryptand slowly releases OH^? ions, according to a defined kinetics, and each OH^? ion displaces a Cl^? ion from the cryptate. Chloride displacement induces a sharp colour change from bright yellow to aquamarine and can be conveniently monitored spectrophotometrically, even in diluted solutions. The 1.1.1‐cryptand is the motor of a molecular dispenser (the dicopper(II) cryptate) delivering chloride ion automatically, from the inside of the solution.     

A new subspace iteration method for the algebraic Riccati equation

We consider the numerical solution of the continuous algebraic Riccati equation A*X + XA ? XFX + G = 0, with F = F*,G = G* of low rank and A large and sparse. We develop an algorithm for the low‐rank approximation of X by means of an invariant subspace iteration on a function of the associated Hamiltonian matrix. We show that the sought‐after approximation can be obtained by a low‐rank update, in the style of the well known Alternating Direction Implicit (ADI) iteration for the linear equation, from which the new method inherits many algebraic properties. Moreover, we establish new insightful matrix relations with emerging projection‐type methods, which will help increase our understanding of this latter class of solution strategies. Copyright © 2014 John Wiley & Sons, Ltd.     

Valorization of Apple Peels through the Study of the Effects on the Amyloid Aggregation Process of κ-Casein

Waste valorization represents one of the main social challenges when promoting a circular economy and environmental sustainability. Here, we evaluated the effect of the polyphenols extracted from apple peels, normally disposed of as waste, on the amyloid aggregation process of κ-casein from bovine milk, a well-used amyloidogenic model system. The effect of the apple peel extract on protein aggregation was examined using a thioflavin T fluorescence assay, Congo red binding assay, circular dichroism, light scattering, and atomic force microscopy. We found that the phenolic extract from the peel of apples of the cultivar “Fuji”, cultivated in Sicily (Caltavuturo, Italy), inhibited κ-casein fibril formation in a dose-dependent way. In particular, we found that the extract significantly reduced the protein aggregation rate and inhibited the secondary structure reorganization that accompanies κ-casein amyloid formation. Protein-aggregated species resulting from the incubation of κ-casein in the presence of polyphenols under amyloid aggregation conditions were reduced in number and different in morphology.     

Smart Coatings Prepared via MAPLE Deposition of Polymer Nanocapsules for Light-Induced Release

Herein, smart coatings based on photo-responsive polymer nanocapsules (NC) and deposited by laser evaporation are presented. These systems combine remotely controllable release and high encapsulation efficiency of nanoparticles with the easy handling and safety of macroscopic substrates. In particular, azobenzene-based NC loaded with active molecules (thyme oil and coumarin 6) were deposited through Matrix-Assisted Pulsed Laser Evaporation (MAPLE) on flat inorganic (KBr) and organic (polyethylene, PE) and 3D (acrylate-based micro-needle array) substrates. SEM analyses highlighted the versatility and performance of MAPLE in the fabrication of the designed smart coatings. DLS analyses, performed on both MAPLE- and drop casting-deposited NC, demonstrated the remarkable adhesion achieved with MAPLE. Finally, thyme oil and coumarin 6 release experiments further demonstrated that MAPLE is a promising technique for the realization of photo-responsive coatings on various substrates.     

Design and Synthesis of New 5-aryl-4-Arylethynyl-1H-1,2,3-triazoles with Valuable Photophysical and Biological Properties

Cu-catalyzed 1,3-dipolar cycloaddition of methyl 2-azidoacetate to iodobuta-1,3-diynes and subsequent Suzuki-Miyaura cross-coupling were used to synthesize new triazoles derivatives: 5-aryl-4-arylethynyl-1H-1,2,3-triazoles. Investigation of their optical properties by using UV absorption and fluorescence emission spectroscopies revealed that all molecules possess fluorescence properties with the values of the Stokes shift more than 100 nm. The photophysical behavior of the two most promising triazoles in polar and non-polar solvents was also studied.     

Volatiles and Antifungal-Antibacterial-Antiviral Activity of South African Salvia spp. Essential Oils Cultivated in Uniform Conditions

Spontaneous emissions of S. dentata Aiton and S. scabra Thunb., as well as the essential oil (EO) composition of the cited species, together with S. aurea L., were investigated. The chemical profile of the first two species is reported here for the first time. Moreover, in vitro tests were performed to evaluate the antifungal activity of these EOs on Trichophyton mentagrophytes, Microsporum canis, Aspergillus flavus, Aspergillus niger, and Fusarium solani. Secondly, the EO antibacterial activity against Escherichia coli, Staphylococcus aureus, and Staphylococcus pseudointermedius was examined, and their antiviral efficacy against the H1N1 influenza virus was assessed. Leaf volatile organic compounds (VOCs), as well as the EOs obtained from the arial part of Salvia scabra, were characterized by a high percentage of sesquiterpene hydrocarbons (97.8% and 76.6%, respectively), mostly represented by an equal amount of germacrene D (32.8% and 32.7%, respectively). Both leaf and flower spontaneous emissions of S. dentata, as well as the EO composition, showed a prevalence of monoterpenes divided into a more or less equal amount of hydrocarbon and oxygenated compounds. Interestingly, its EO had a non-negligible percentage of oxygenated sesquiterpenes (29.5%). S. aurea EO, on the contrary, was rich in sesquiterpenes, both hydrocarbons and oxygenated compounds (41.5% and 33.5%, respectively). S. dentata EO showed good efficacy (Minimal Inhibitory Concentration (MIC): 0.5%) against M. canis. The tested EOs were not active against E. coli and S. aureus, whereas a low inhibition of S. dentata EO was observed on S. pseudointermedius (MIC = 10%). Once again, S. dentata EO showed a very good H1N1 inhibition; contrariwise, S. aurea EO was completely inactive against this virus. The low quantity of S. scabra EO made it impossible to test its biological activity. S. dentata EO exhibited interesting new perspectives for medicinal and industrial uses.     

Differential tissue expression of a calpastatin isoform in Xenopus embryos

This study is aimed at demonstrating the role played by a calpastatin isoform (Xcalp3) in Xenopus embryos. A specific monoclonal antibody (mAb) was raised against a glutathione S-transferase (GST)-Xcalp3 fusion protein and characterized by immunoblotting and confocal fluorescence microscopy on stage 20-36 embryos. Under these conditions, calpastatin reactivity is associated with a major 110kDa protein fraction and preferentially expressed by notochord and somitic cells. In notochord cells, anti-calpastatin reactive sites were initially restricted to the luminal space of the vacuoles and later became diffused throughout the cytoplasm. In contrast, anti-calpastatin reactive sites in somitic cells were initially diffused throughout the cytoplasm and became restricted to a few intracellular granules in the later developmental stages. At the ultrastructural level, notochord cells appeared as flattened discs containing several vacuoles and numerous electron-dense granules. During transition from stages 26 to 32, electron-dense granules were gradually reduced in number as vacuoles enlarged in size and losed their calpastatin reactivity. Electron-dense granules were also present in myoblast cells and their number gradually reduced during development. To determine whether these observations bear any causal relationship to the calpain/calpastatin system, a number of Xenopus embryos were examined both ultrastructurally and histochemically following exposure to a specific calpain inhibitor (CI3). Under these conditions, Xenopus embryos exhibited an altered right-left symmetry and an abnormal axial shortening. In CI3-treated stage 32 embryos, notochord cells had a reduced vacuolar extension and exhibited at the same time an increase in granular content. The overall morphology of the somites was also distorted and myoblasts were altered both in shape and granular content. Based on these findings, it is concluded that the calpain/calpastatin may play an important role in the control of notochord elongation and somite differentiation during Xenopus embryogenesis.     

Polymer Lamellae as Reaction Intermediates in the Formation of Copper Nanospheres as Evidenced by In Situ X‐ray Studies

The classical nucleation theory (CNT) is the most common theoretical framework used to explain particle formation. However, nucleation is a complex process with reaction pathways which are often not covered by the CNT. Herein, we study the formation mechanism of copper nanospheres using in situ X‐ray absorption and scattering measurements. We reveal that their nucleation involves coordination polymer lamellae as pre‐nucleation structures occupying a local minimum in the reaction energy landscape. Having learned this, we achieved a superior monodispersity for Cu nanospheres of different sizes. This report exemplifies the importance of developing a more realistic picture of the mechanism involved in the formation of inorganic nanoparticles to develop a rational approach to their synthesis.     

The Use of Constituent Spectra and Weighting in Extended Multiplicative Signal Correction in Infrared Spectroscopy

Extended multiplicative signal correction (EMSC) is a widely used preprocessing technique in infrared spectroscopy. EMSC is a model-based method favored for its flexibility and versatility. The model can be extended by adding constituent spectra to explicitly model-known analytes or interferents. This paper addresses the use of constituent spectra and demonstrates common pitfalls. It clarifies the difference between analyte and interferent spectra, and the importance of orthogonality between model spectra. Different normalization approaches are discussed, and the importance of weighting in the EMSC is demonstrated. The paper illustrates how constituent analyte spectra can be estimated, and how they can be used to extract additional information from spectral features. It is shown that the EMSC parameters can be used in both regression tasks and segmentation tasks.