The mechanism of formation of amide-based interlocked compounds: prediction of a new rotaxane-forming motif

Molecular modeling of four different reagent systems shows that the (free) energies of supramolecular interactions in the gas phase and in solution can explain the different reaction products (i.e., various sized macrocycles, catenanes, and linear oligomers) that are formed in classic amide-catenane-forming reactions. Self-assembly of the catenanes requires the formation of ordered intertwined chains and is driven by bifurcated hydrogen bonds, with pi stacking only playing a lesser role. The understanding gained from the computational study was used to predict the possibility of a new rotaxane-forming system that does not permit catenane formation. The predictions were confirmed by the successful synthesis and characterization (including X-ray crystallography) of two novel rotaxanes.     

Glycosidic monoterpenes from Linaria capraria

During our systematic study on the species of genus Linaria (Scrophulariaceae) present in Italy, we examined the glycosidic fraction of Linaria capraria Moris et De Not., a species endemic of Tuscany archipelago. This fraction is particularly complex and we considered in this article only the medium polarity components. In accordance with previous studies, L. capraria shows acyl derivatives of antirrhinoside 1 as specific chemotaxonomic iridoidic markers. L. capraria exhibits a complex composition, with regard to iridoidic constituents, with several chromatographic problems to be resolved. We then isolated, besides the known antirrhinoside 1, two acyl derivatives of antirrhinoside, the 6'-O-senecioyl derivative, 2, and the 6'-O-angeloyl derivative, 3. In addition a glucoside of an acyclic monoterpene, 4, was also isolated, which may be correlated to the other monoterpenic glycosides isolated from other species of Scrophulariaceae.     

Characterization of a Pd-Fe bimetallic model catalyst

Small bimetallic Pd-Fe particles supported on a well ordered alumina film grown on NiAl (1 1 0) were studied focusing on the geometric, electronic, adsorption, as well as magnetic properties. The morphology, growth mode and surface composition were investigated by combining scanning tunneling microscopy (STM), temperature-programmed desorption (TPD) and infrared spectroscopy (IRAS) using CO as a probe molecule. Information on the electronic properties of the bimetallic systems was obtained by means of X-ray photoelectron spectroscopy (XPS). These measurements were amended by in situ ferromagnetic resonance spectroscopy to address the magnetic properties of the bimetallic particles. The subsequent deposition of the metals at 300 K varying the order of metal deposition resulted in two distinct bimetallic systems. Pd deposited on existing Fe particles forms a shell, however, FMR and XPS suggest that intermixing of Pd and Fe occurs to some extent. For the reverse order, a larger amount of Fe is required to coat Pd particles, due to the strong tendency of Pd to segregate to the surface of the particles.     

Water-Assisted Concerted Proton-Electron Transfer at Co(II)-Aquo Sites in Polyoxotungstates With Photogenerated RuIII(bpy)33+ Oxidant

The cobalt substituted polyoxotungstate [Co₆(H₂O)₂(α-B-PW₉O₃₄)₂(PW₆O₂₆)]¹⁷⁻ ( Co6 ) displays fast electron transfer (ET) kinetics to photogenerated Ru^III(bpy)₃³⁺, 4 to 5 orders of magnitude faster than the corresponding ET observed for cobalt oxide nanoparticles. Mechanistic evidence has been acquired indicating that: (i) the one-electron oxidation of Co6 involves Co(II) aquo or Co(II) hydroxo groups (abbreviated as Co6(II) −OH ₂ and Co6(II) −OH, respectively, whose speciation in aqueous solution is associated to a pK_a of 7.6), and generates a Co(III)−OH moiety ( Co6(III) −OH), as proven by transient absorption spectroscopy; (ii) at pH>pK_a, the Co6(II) −OH→Ru^III(bpy)₃³⁺ ET occurs via bimolecular kinetics, with a rate constant k close to the diffusion limit and dependent on the ionic strength of the medium, consistent with reaction between charged species; (iii) at pH <pK_a, the process involves Co6(II) − OH₂ → Co6(III)−OH transformation and proceeds via a multiple-site, concerted proton electron transfer (CPET) where water assists the transfer of the proton, as proven by the absence of effect of buffer base concentrations on the rate of the ET and by a H/D kinetic isotope in a range of 1.2–1.4. The reactivity of water is ascribed to its organization on the surface of the polyanionic scaffold through hydrogen bond networking involving the Co(II)−OH₂ group.     

Dysregulation of chemo-cytokine production in schizophrenic patients versus healthy controls

Background  

The exact cause of schizophrenia is not known, although several aetiological theories have been proposed for the disease, including developmental or neurodegenerative processes, neurotransmitter abnormalities, viral infection and immune dysfunction or autoimmune mechanisms. Growing evidence suggests that specific cytokines and chemokines play a role in signalling the brain to produce neurochemical, neuroendocrine, neuroimmune and behavioural changes. A relationship between inflammation and schizophrenia was supported by abnormal cytokines production, abnormal concentrations of cytokines and cytokine receptors in the blood and cerebrospinal fluid in schizophrenia. Since the neuropathology of schizophrenia has recently been reported to be closely associated with microglial activation we aimed to determined whether spontaneous or LPS-induced peripheral blood mononuclear cell chemokines and cytokines production is dysregulated in schizophrenic patients compared to healthy subjects. We enrolled 51 untreated first-episode schizophrenics (SC) and 40 healthy subjects (HC) and the levels of MCP-1, MIP-1α, IL-8, IL-18, IFN-γ and RANTES were determined by Elisa method in cell-free supernatants of PBMC cultures.     

Aλδ-calculus with an algorithmicδ

In this paper we propose a system, based on-calculus, where the restriction of Church's to normal forms is dropped, while the monotony properties are weakened. The main feature of such a system is that the Church-Rosser property is maintained and all provable equalities between closed terms are semidecidable within it.     

7‐Chloro‐3,6‐di­methyl‐1H‐indene‐2‐carb­aldehyde

In the crystal structure of C₁₂H₁₁ClO, the (planar) mol­ecules give rise to a parallel packing. A model crystal obtained by semi‐empirical and packing‐energy calculations is consistent with the observed structure.     

A biofunctional polymeric coating for microcantilever molecular recognition

An innovative route to activate silicon microcantilevers (MCs) for label free molecular recognition is presented. The method consists in coating the underivatized MCs with a functional ter-polymer based on N,N-dimethylacrylamide (DMA) bearing N-acryloyloxysuccinimide (NAS) and 3-(trimethoxysilyl)propyl-methacrylate (MAPS), two functional monomers that confer to the polymer the ability to react with nucleophilic species on biomolecules and with glass silanols, respectively. The polymer was deposited onto MCs by dip coating. Polymer coated MCs were tested in both static and dynamic modes of actuation, featuring detection of DNA hybridization as well as protein/protein interaction. In the dynamic experiments, focused on protein detection, the MCs showed an average mass responsivity of 0.4 Hz/pg for the first resonant mode and of 2.5 Hz/pg for the second resonant mode. The results of the static experiments, dedicated to DNA hybridization detection, allowed for direct estimation of the DNA duplex formation energetics, which resulted fully consistent with the nominal expected values. These results, together with easiness and cheapness, high versatility, and excellent stability of the recognition signal, make the presented route a reliable alternative to standard SAM functionalization (for microcantilevers (MCs) and for micro-electro-mechanical systems (MEMS) in general).     

Pseudodistances and Pseudometrics on real and complex manifolds

Summary In this paper we study the relationships between a class of distances and infinitesimal metrics on real and complex manifolds and their behavior under differentiable and holomorphic mappings. Some application to Riemannian and Finsler geometry are given and also new proofs and generalizations of some results of Royden, Harris and Reiffen on Kobayashi and Carathéodory metrics on complex manifolds are obtained. In particular we prove that on every complex manifold (finite or infinite- dimensional) the Kobayashi distance is the integrated form of the corresponding infinitesimal metric.     

Penkvilksite‐2O: Na2TiSi4O11·2H2O

The crystal structure of synthetic penkvilksite‐2O, disodium titanium tetrasilicate dihydrate, Na₂TiSi₄O₁₁·2H₂O, a microporous titanosilicate, confirms the major features of a previous model that had been obtained by order–disorder (OD) theory from the known structure of penkvilksite‐1M. An important difference from the previous model involves the hydrogen bonding of the water molecule which, on the basis of a Raman spectrum and the finding of only one of the two H atoms, is proposed to be disordered about a fixed O–H direction. The structure of penkvilksite‐2O is based on (100) silicate layers linked by isolated TiO₆ octahedra to form a heteropolyhedral framework. The layer is strongly corrugated, based on interlaced spiral chains, and is crossed by two different channels that have an effective channel width of about 3 Å.