Design of Highly Stable Echogenic Microbubbles through Controlled Assembly of Their Hydrophobin Shell

Dispersing hydrophobin HFBII under air saturated with perfluorohexane gas limits HFBII aggregation to nanometer‐sizes. Critical basic findings include an unusual co‐adsorption effect caused by the fluorocarbon gas, a strong acceleration of HFBII adsorption at the air/water interface, the incorporation of perfluorohexane into the interfacial film, the suppression of the fluid‐to‐solid 2D phase transition exhibited by HFBII monolayers under air, and a drastic change in film elasticity of both Gibbs and Langmuir films. As a result, perfluorohexane allows the formation of homogenous populations of spherical, narrowly dispersed, exceptionally stable, and echogenic microbubbles.     

Site- and orientation-selective anchoring of a prototypical molecular building block

The controlled anchoring of molecular building blocks on appropriate templates is a major prerequisite for the rational design and fabrication of supramolecular architectures on surfaces. We report on a particularly selective adsorption process of hexa-peri-hexabenzocoronene on Au(111), which leads to well-controlled adsorption position and orientation of the polycyclic aromatic hydrocarbons. Scanning tunneling microscopy reveals selective adsorption on monatomic steps in the fcc stacking regions with a specific orientation of 18 degrees between the molecular axis and the step normal. Ab initio calculations for various adsorption sites reveal the lowest total energy for adsorption on a kink site. Energy considerations and the excellent agreement between experimental and simulated images show that adsorption on kink sites is responsible for the specific adsorption angle.     

Tuning second-order NLO responses through halogen bonding

As a function of the ability of the solvent to behave as acceptor of halogen bonding, the NLO-phores under study give rise to microbeta(lambda) values ranging from +192 x 10(-48) esu to -465 x 10(-48) esu.     

A time series approach for clustering mass spectrometry data

Advanced statistical techniques and data mining methods have been recognized as a powerful support for mass spectrometry (MS) data analysis. Particularly, due to its unsupervised learning nature, data clustering methods have attracted increasing interest for exploring, identifying, and discriminating pathological cases from MS clinical samples. Supporting biomarker discovery in protein profiles has drawn special attention from biologists and clinicians. However, the huge amount of information contained in a single sample, that is, the high-dimensionality of MS data makes the effective identification of biomarkers a challenging problem.In this paper, we present a data mining approach for the analysis of MS data, in which the mining phase is developed as a task of clustering of MS data. Under the natural assumption of modeling MS data as time series, we propose a new representation model of MS data which allows for significantly reducing the high-dimensionality of such data, while preserving the relevant features. Besides the reduction of high-dimensionality (which typically affects effectiveness and efficiency of computational methods), the proposed representation model of MS data also alleviates the critical task of preprocessing the raw spectra in the whole process of MS data analysis. We evaluated our MS data clustering approach to publicly available proteomic datasets, and experimental results have shown the effectiveness of the proposed approach that can be used to aid clinicians in studying and formulating diagnosis of pathological states.     

LOW MACH NUMBER LIMIT ON EXTERIOR DOMAINS Dedicated to Professor Constantine M. Dafermos on the occasion of his 70th birthday

This paper is concerned with the low Mach number limit for the compressible Navier-Stokes equations in an exterior domain.We present here an approach based on Strichartz estimate defined on a non trapping exterior domain and we will be able to show the compactness and strong convergence of the velocity vector field.     

Halide anions driven self-assembly of haloperfluoroarenes: Formation of one-dimensional non-covalent copolymers

The supramolecular organization in six solid assemblies involving iodo- and bromoperfluoroarene derivatives is described. Single crystal X-ray analyses show that the formation of the supramolecular architectures is controlled by I⁻?Br–Ar_F, I⁻?I–Ar_F, Br⁻?I–Ar_F, and Cl⁻?I–Ar_F halogen bondings thus proving the X⁻?X′–Ar_F supramolecular synthon, where X can be the same as or different from X′, is particularly robust. In five of the described architectures halide anions form two halogen bondings and form infinite chains wherein dihaloperfluoroarenes, which function as bidentate electron acceptors, and halide anions, which function as bidentate electron donors, alternate. This behaviour shows halide anions have a fair tendency to work as bidentate halogen bonding acceptors.     

An infinite class of maximal intermediate propositional logics with the disjunction property

Summary Infinitely many intermediate propositional logics with the disjunction property are defined, each logic being characterized both in terms of a finite axiomatization and in terms of a Kripke semantics with the finite model property. The completeness theorems are used to prove that any two logics are constructively incompatible. As a consequence, one deduces that there are infinitely many maximal intermediate propositional logics with the disjunction property.     

Engineering functional materials by halogen bonding

Engineering functional materials endowed with unprecedented properties require the exploitation of new intermolecular interactions, which can determine the characteristics of the bulk materials. The great potential of Halogen Bonding (XB), namely any noncovalent interaction involving halogens as electron acceptors, in the design of new and high‐value functional materials is now emerging clearly. This Highlight will give a detailed overview on the energetic and geometric features of XB, showing how some of them are quite constant in most of the formed supramolecular complexes (e.g., the angle formed by the covalent and the noncovalent bonds around the halogen atom), while some others depend strictly on the nature of the interacting partners. Then, several specific examples of halogen‐bonded supramolecular architectures, whose structural aspects as well as applications in fields as diverse as enantiomers' separation, crystal engineering, liquid crystals, natural, and synthetic receptors, will be fully described. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: PolymChem 45: 1–15, 2007     

Protocell Communication through the Eyes of Synthetic Organic Chemists

The bottom-up fabrication of synthetic cells (protocells) from molecules and materials, is a major challenge of modern chemistry. A significant breakthrough has been the engineering of protocells capable of chemical communication using bio-derived molecules and ex situ stabilised cell machineries. These, however, suffer from short shelf-lives, high costs, and require mild aqueous conditions. In this Concept Article we analyse the chemistry at the heart of protocell communication to highlight new opportunities for synthetic chemists in protocell engineering. Specifically, we (i) categorise the main bio-derived chemical communication machineries in enzyme cascades, DNA strand displacement, and gene-mediated communication; (ii) review the chemistries of these signal transduction machineries; and (iii) introduce new types of bio-inspired, fully synthetic artificial enzymes to replace their natural counterparts. Developing protocells that incorporate synthetic analogues of bio-derived signal transduction machineries will improve the robustness, stability, and versatility of protocells, and broaden their applications to highly strategic fields such as photocatalysis and fine chemicals production.