Extension operators via semigroups

The Roper-Suffridge extension operator and its modifications are powerful tools to construct biholomorphic mappings with special geometric properties. The first purpose of this paper is to analyze common properties of different extension operators and to define an extension operator for biholomorphic mappings on the open unit ball of an arbitrary complex Banach space. The second purpose is to study extension operators for starlike, spirallike and convex in one direction mappings. In particular, we show that the extension of each spirallike mapping is A-spirallike for a variety of linear operators A. Our approach is based on a connection of special classes of biholomorphic mappings defined on the open unit ball of a complex Banach space with semigroups acting on this ball.     

Identification of ancient gilding technology and Late Bronze Age metallurgy by EDXRF, Micro-EDXRF, SEM-EDS and metallographic techniques

A combination of analytical techniques capable of elemental and microstructural characterisation was used for the identification of ancient gilding technology and bronze metallurgy. EDXRF, micro-EDXRF, SEM-EDS analysis and metallographic examinations were applied in the study of artefacts dating to the end of the second millennium BC from Crasto de São Romão in Central Portugal. Results report to the finding of an exceptional gilded copper nail among bronze artefacts with 9 wt.% to15 wt.% tin and minute other metallic impurities. Additionally, analysis of a crucible fragment points out for bronze production at the archaeological site. EDXRF and micro-EDXRF analysis made on the copper nail showed that it was gilded only on the front side of the head, and that the gold layer has been lost in the most exposed areas. SEM-EDS analysis showed that the gold layer has 5–8 µm in thickness and is covered with a thick corrosion layer. The gilding technique is discussed based on the gold layer composition and gold/copper substrate interface. So far, this object seems to be the first diffusion gilded artefact identified in the Portuguese territory dated to Late Bronze Age.     

A systematic study of the solid state and solution phase conformational preferences of β-peptides derived from C(3)-alkyl substituted transpentacin derivatives

The solid state and solution phase conformational preferences of a homologous series of β-peptides derived from a range of 2-amino-3-alkylcyclopentanecarboxylic acid residues have been investigated using a variety of spectroscopic and crystallographic techniques. These studies indicate that C(3)-alkyl substitution trans to the amino group on the cyclopentane backbone is tolerated by the established 12-helix secondary structural preference of the parent pentamer and hexamer derived from 2-aminocyclopentanecarboxylic acid (transpentacin) residues in both the solid state and solution phase. Evidence for the alternative turn type conformation identified for the C(3)-unsubstituted tetramer was not observed in the C(3)-alkyl substituted derivatives, consistent with the alkyl substituent anti to the amino functionality destabilising this motif. These results suggest that oligomers based around the transpentacin scaffold may be amenable to further elaboration at C(3) anti to the amino group with retention of the secondary structure.     

Development of new coarse-grained models for chromonic liquid crystals: insights from top-down approaches

ABSTRACT

Two top-down coarse-grained molecular simulation models for a chromonic liquid crystal, 3,6,7,10,11-hexa-(1,4,7-trioxa-octyl)-triphenylene, are tested. We use an extension of the well-known MARTINI model and develop a new coarse-grained model based on statistical associating fluid theory (SAFT)-γ perturbation theory. For both models, we demonstrate self-assembly in the isotropic phase of the chromonic and we test the effectiveness of both models in terms of the structures of the chromonic aggregates that are produced in solution and the thermodynamics of association. The latter is tested by calculations of the potential of mean force for dimers in solution, which measures the strength of molecular association. SAFT-γ provides valuable insights into the thermodynamics of assembly. Exploration of a range of interactions between unlike sites demonstrates that chromonic self-assembly only occurs in a small parameter space where the hydrophilic–lipophilic balance between aromatic core and ethylene oxide chains is optimal. Outside of this balance, chromonic self-assembly is replaced by the formation of conglomerates of molecules or short stacks.     

Inclusions and metal composition of ancient copper‐based artefacts: a diachronic view by micro‐EDXRF and SEM‐EDS

A diachronic view of the metallurgy in the Portuguese territory during the first three millennia after its appearance in the Iberian Peninsula is presented based on the current state of the art. Results of micro‐energy dispersive X‐ray fluorescence (micro‐EDXRF) analyses made on metal artefacts to determine their composition and scanning electron microscopy with energy dispersive analysis (SEM‐EDS) analyses to study microstructural features as inclusions are shown to illustrate trends and specificities of each chronological period. Generally, in early periods, namely during the Copper Age and first stages of the Bronze Age, unalloyed copper and arsenical copper were at use, and only by the Late Bronze Age (LBA) did tin bronze substitute almost completely the previous role of copper. In the Early Iron Age, during the Orientalising period, a general decrease in the average tin content in bronzes seems to happen. Regarding the inclusions observed in the metal matrix, these seem to suffer a diversification with the appearance of tin bronzes. By the Copper Age, only Cu? O and Cu? As? O inclusions are observed, while by the LBA Cu? S inclusions become regular, besides others less frequent, as Sn? O, Cu? S? Fe and Pb globules. Overall, with the present analytical study, the complementary character of micro‐EDXRF and SEM‐EDS in the study of ancient metals is demonstrated, providing a first general overview of the ancient metallurgy at the Portuguese territory which is of key importance to specific investigations of the future. Copyright © 2011 John Wiley & Sons, Ltd.     

In situ measurements of the formation and morphology of intracellular β-amyloid fibrils by super-resolution fluorescence imaging

Misfolding and aggregation of peptides and proteins is a characteristic of many neurodegenerative disorders, including Alzheimer's disease (AD). In AD the β-amyloid peptide (Aβ) aggregates to form characteristic fibrillar structures, which are the deposits found as plaques in the brains of patients. We have used direct stochastic optical reconstruction microscopy, dSTORM, to probe the process of in situ Aβ aggregation and the morphology of the ensuing aggregates with a resolution better than 20 nm. We are able to distinguish different types of structures, including oligomeric assemblies and mature fibrils, and observe a number of morphological differences between the species formed in vitro and in vivo, which may be significant in the context of disease. Our data support the recent view that intracellular Aβ could be associated with Aβ pathogenicity in AD, although the major deposits are extracellular, and suggest that this approach will be widely applicable to studies of the molecular mechanisms of protein deposition diseases.     

Aerodynamic and acoustic voice measurements of patients with vocal nodules: variation in baseline and changes across voice therapy.

An important clinical issue concerns the efficacy of current voice therapy approaches in treating voice disorders, such as vocal nodules. Much research focuses on finding reliable methods for documentation of treatment results. In this second treatment study of ten patients with vocal nodules, who participated in a behaviorally based voice therapy program, 11 aerodynamic (transglottal air pressure and glottal waveform) and acoustic (spl, f0, and spectrum slope) measures were used. Three pretherapy baseline assessments were carried out, followed by one assessment after each of five therapy phases. Measurements were made of two types of speech materials: Strings of repeated /pae/ syllables and sustained /ae/ phonations in two loudness conditions: comfortable loudness and loud voice. The data were normalized using z-scores, which were based on data from 22 normal subjects. The results showed that the aerodynamic measures reflected the presence of vocal pathology to a higher degree than did the acoustic spectral measures, and they should be useful in studies comparing nodule and normal voice production. Large individual session-to-session variation was found for all measures across pretherapy baseline recordings, which contributed to nonsignificant differences between baseline and therapy data.     

Metal‐Free One‐Pot Synthesis of Benzofurans

Ethyl acetohydroxamate was efficiently arylated with diaryliodonium salts at room temperature under transition‐metal‐free conditions. The obtained O‐arylated products were reacted in situ with ketones under acidic conditions to yield substituted benzo[b]furans through oxime formation, [3,3]‐rearrangement, and cyclization in a fast and operationally simple one‐pot fashion without using excess reagents. Alternatively, the O‐arylated products could be isolated or transformed in situ to aryloxyamines or O‐arylaldoximes. The methodology was applied to the synthesis of Stemofuran A and the formal syntheses of Coumestan, Eupomatenoid 6, and (+)‐machaeriol B.     

Laux‐type Oxidation of In0 Nanoparticles to In2O3 Retaining Particle Size and Colloidal Stability

As a conceptual study, In⁰ nanoparticles are obtained by NaBH₄‐driven reduction of InCl₃ · 4H₂O and transferred from a polar/hydrophilic diethylene glycol phase to a non‐polar hydrophobic dodecane phase for purification and stabilization. Finally, the In⁰ nanoparticles are oxidized via a Laux‐like reaction with nitrobenzene to In₂O₃ nanoparticles. The challenge of the reaction is to perform the final oxidation to In₂O₃ under mild conditions with the colloidal stability, particle size and particle size distribution of the initial In⁰ nanoparticles retained. To this concern, the mean diameter of the initial In⁰ nanoparticles changed from 11(1) to 14(2) nm of the oxidized In₂O₃ nanoparticles. Such multi‐step reaction, including reduction, nucleation, phase transfer, exchange of surface capping and oxidation are of increasing importance for nanoparticles. Especially, Laux‐type conditions with nitrobenzene as a molecular oxidizing agent of nanoparticles have not been used till now. Particle size, size distribution and chemical composition of the In⁰ and In₂O₃ nanoparticles are analyzed by DLS, SEM, XRD, FT‐IR and HRTEM.