Comparison of binding behavior for molecularly imprinted polymers prepared by hierarchical imprinting or Pickering emulsion polymerization

The aim of this study was the evaluation of the binding performances and selectivity of molecularly imprinted beads prepared toward several penicillins (i) by hierarchical bulk polymerization in the pores of template‐grafted silica microbeads (hMIPs) and (ii) by Pickering emulsion polymerization in the presence of template‐decorated silica nanobeads (pMIPs). 6‐Aminopenicillanic acid was chosen as the common fragmental mimic template. Both approaches produced micron‐sized polymeric beads with good recognition properties toward the target ligands whereas the selectivity pattern appeared quite different. The polymer prepared by the Pickering emulsion approach showed binding properties similar to imprinted beads prepared by hierarchical approach. Equilibrium binding constants changed their values from 0.1–0.2 × 10⁶ (hMIPs) to 0.2–0.6 × 10⁶ M^?1 (pMIPs), while the binding site densities changed from 3.7–4.8 (hMIPs) to 0.3–0.55 μmol/g (pMIPs). Compared to the hierarchical polymerization, Pickering emulsion polymerization represents a more practical approach when a template mimic needs to be used.     

Intermolecular electronic excitation transfer in a confined space: a first-principles study.

The process of intermolecular electronic excitation transfer (EET) in a monodimensional supramolecular arrangement of molecules in confined space has been modelled and investigated by means of first-principles molecular dynamics simulations. The chosen model system consists of a wire of chlorine molecules hosted in the noncrossing channels of the zeolite bikitaite. The time evolution of the system in its first excited singlet state has been described by the restricted open shell Kohn-Sham formalism. Simulation results have highlighted that excitation, initially localized on a guest molecule, is transferred to an adjacent moiety in the molecular wire on the picosecond scale via a collision-induced Dexter-type short range EET. Analysis of the modifications of the electronic structure of the system brought about by EET has given insight into the microscopic details of the process.     

Nuclear magnetic resonance for cultural heritage

Nuclear magnetic resonance (NMR) portable devices are now being used for nondestructive in situ analysis of water content, pore space structure and protective treatment performance in porous media in the field of cultural heritage. It is a standard procedure to invert T(1) and T(2) relaxation data of fully water-saturated samples to get "pore size" distributions, but the use of T(2) requires great caution. It is well known that dephasing effects due to water molecule diffusion in a magnetic field gradient can affect transverse relaxation data, even if the smallest experimentally available half echo time tau is used in Carr-Purcell-Meiboom-Gill experiments. When a portable single-sided NMR apparatus is used, large field gradients due to the instrument, at the scale of the sample, are thought to be the dominant dephasing cause. In this paper, T(1) and T(2) (at different tau values) distributions were measured in natural (Lecce stone) and artificial (brick samples coming from the Greek-Roman Theatre of Taormina) porous media of interest for cultural heritage by a standard laboratory instrument and a portable device. While T(1) distributions do not show any appreciable effect from inhomogeneous fields, T(2) distributions can show strong effects, and a procedure is presented based on the dependence of 1/T(2) on tau to separate pore-scale gradient effects from sample-scale gradient effects. Unexpectedly, the gradient at the pore scale can be, in some cases, strong enough to make negligible the effects of gradients at the sample scale of the single-sided device.     

Perilla frutescens: interesting new medicinal and melliferous plant in Italy

The goal of this study is to inform those potentially interested (researchers, farmers, industry and public bodies) in the medicinal and aromatic properties, and profitability of Perilla frutescens (L.) Britton (Lamiaceae). Perilla, a medicinal and edible plant of Asian origin, was recently introduced to the Piedmont Region in the north-west of Italy. P. frutescens is commonly known for its anti-allergic, anti-tumor, and anti-oxidant properties. It is also widely used as human food. We collected a variety of data on Perilla crops in the Piedmont Region, including: agricultural practices, crop profitability, and its value as a bee plant. Our results suggest that ease of cultivation, approximate break-even economics, medicinal claims, and value for bees all contribute to make Perilla of economic interest in Italy.     

Iron doping of lithium niobate by thermal diffusion from thin film: study of the treatment effect

Thermal diffusion from thin film is one of the most widespread approaches to prepare iron doped regions in lithium niobate with limited size for photorefractive applications. In this work, we investigate the doping process with the aim of determining the best process conditions giving a doped region with the characteristics required for photorefractive applications. Six samples were prepared by changing the atmosphere employed in the diffusion treatment in order to obtain different combination of diffusion profiles and reduction degrees and also to check the effect of employing a wet atmosphere. The compositional, optical, and structural properties are then extensively characterized by combining Secondary ion Mass Spectrometry, UV, visible and IR spectrophotometry, High Resolution X-Rays Diffraction, and Micro-Raman Spectroscopy. Moreover, the sample topography was checked by Atomic Force Microscopy. An analysis of all our data shows that the best results are obtained performing a double step process, i.e. diffusion in oxidizing atmosphere and subsequent reduction at lower temperature in an hydrogen-containing atmosphere.     

Analysis of tapered front‐coupling X‐ray waveguides

The coupling and propagation of electromagnetic waves through planar X‐ray waveguides (WG) with vacuum gap and Si claddings are analyzed in detail, starting from the source and ending at the detector. The general case of linearly tapered WGs (i.e. with the entrance aperture different from the exit one) is considered. Different kinds of sources, i.e. synchrotron radiation and laboratory desk‐top sources, have been considered, with the former providing a fully coherent incoming beam and the latter partially coherent beams. It is demonstrated that useful information about the parameters of the WG can be derived, comparing experimental results with computer simulation based on analytical solutions of the Helmholtz equation which take into account the amplitude and phase matching between the standing waves created in front of the WG, and the resonance modes propagating into the WG.     

Reconstructing Nonparametric Productivity Networks

Network models provide a general representation of inter-connected system dynamics. This ability to connect systems has led to a proliferation of network models for economic productivity analysis, primarily estimated non-parametrically using Data Envelopment Analysis (DEA). While network DEA models can be used to measure system performance, they lack a statistical framework for inference, due in part to the complex structure of network processes. We fill this gap by developing a general framework to infer the network structure in a Bayesian sense, in order to better understand the underlying relationships driving system performance. Our approach draws on recent advances in information science, machine learning and statistical inference from the physics of complex systems to estimate unobserved network linkages. To illustrate, we apply our framework to analyze the production of knowledge, via own and cross-disciplinary research, for a world-country panel of bibliometric data. We find significant interactions between related disciplinary research output, both in terms of quantity and quality. In the context of research productivity, our results on cross-disciplinary linkages could be used to better target research funding across disciplines and institutions. More generally, our framework for inferring the underlying network production technology could be applied to both public and private settings which entail spillovers, including intra- and inter-firm managerial decisions and public agency coordination. This framework also provides a systematic approach to model selection when the underlying network structure is unknown.     

Moduli of roots of line bundles on curves

We treat the problem of completing the moduli space for roots of line bundles on curves. Special attention is devoted to higher spin curves within the universal Picard scheme. Two new different constructions, both using line bundles on nodal curves as boundary points, are carried out and compared with pre-existing ones.

     

Insights into molecular recognition of Lewis(X) mimics by DC-SIGN using NMR and molecular modelling

In this work, we have studied in detail the binding of two α-fucosylamide-based mimics of Lewis(X) to DC-SIGN ECD (ECD = extracellular domain) using STD NMR and docking. We have concluded that the binding mode occurs mainly through the fucose moiety, in the same way as Lewis(X). Similarly to other mimics containing mannose or fucose previously studied, we have shown that both compounds bind to DC-SIGN ECD in a multimodal fashion. In this case, the main contact is the interaction of two hydroxyl groups one equatorial and the other one axial (O3 and O4) of the fucose with the Ca(2+) as Lewis(X) and similarly to mannose-containing mimics (in this case the interacting groups are both in the equatorial position). Finally, we have measured the K(D) of one mimic that was 0.4 mM. Competitive STD NMR experiments indicate that the aromatic moiety provides additional binding contacts that increase the affinity.     

Nanostructural Organization of Ionic Liquids: Theoretical and Experimental Evidences of the Presence of Well Defined Local Structures in Ionic Liquids

From an overview of the different theoretical and experimental methods it was possible to evidence the presence of aggregates in ionic liquids (ILs), and to specify their role in determining the unique physical-chemical properties of these media. An understanding of the structure of ILs, as pure compounds or in the presence of dissolved species, is fundamental if the reactivity and selectivity in ILs mediated reactions is to become predictive.