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We present the determination of the conformational properties ofaeroplysinin-1 in aqueous solution by means of a combined experimentaland theoretical Raman optical activity (ROA) and vibrational circulardichroism (VCD) study. Aeroplysinin-1 is an antiangiogenic drug extractedfrom the sponge Aplysina cavernicolawhich has beenproved to be a valuable candidate for the treatment of cancer andother antiangiogenic diseases. Our study shows that this moleculepossesses the 1S,6Rabsolute configurationin aqueous solution, where only two conformers are present to a significantlevel. We discuss in detail the relationships between the chiro-opticalROA and VCD features, and the structural properties of various energyaccessible conformers are described. The present work is one of thefirst studies in which both ROA and VCD have been used as complementarytools for the determination of absolute configuration and dominantsolution-state conformations of an unknown therapeutically significantmolecule. [ABSTRACT FROM AUTHOR]

Pleural effusion is increasingly reported in children. Standard culture of blood or pleural fluid is frequently negative and molecular diagnosis by polymerase chain reaction is not available in all hospitals. The Binax NOW Streptococcus pneumoniae Antigen test (Binax, Portland, USA) is a rapid immunochromatographic test (ICT) for the detection of the C polysaccharide antigen. We evaluated the Binax NOW test on the pleural fluid of 73 children hospitalized with pleural effusion over a period of 4 years. In our sample, the sensitivity and specificity of ICT were high (88% and 71%, respectively), with a positive predictive value of 96%. Detection of the pneumococcal antigen in pleural fluid by ICT is easy and quick, and enables us to identify the pneumococcal origin of the effusion, thus, making the treatment of complicated pneumonia suitably and early. [ABSTRACT FROM AUTHOR]

Assuming that the Universe is spatially infinite, we depict a simple model where gravitation does not decelerate the expansion, which occurs at constant speed for any two distant galaxies. This Steady Flow model fits the SNe Ia observations without a repulsive dark energy. We review the main problems of Big Bang cosmology and see how they can be solved. Particularly, the singularity and the problem of the cosmic origin could be avoided in our framework. The time evolution of the scale factor (R ∞ t) leaves a longer period for early structure and galaxy formation. However, the expansion time coincides with the Universe age of the standard model. Other features of Big Bang, such as the evolution of temperature with the scale factor and the primordial nucleosynthesis, remain unchanged. [ABSTRACT FROM AUTHOR]

The transposition of European Union directives involves the reconciliation of domestic and European interests. More often than not, domestic politics overrule European requirements to comply in a timely and correct manner. This domestication of the transposition process has often been observed in states belonging to the "world of domestic politics", one of the least researched country clusters in the "worlds of compliance" typology developed by Falkner et al. (2005). This paper provides additional empirical evidence on how domestic politics overrule European demands once a conflict between both levels occurs. This is done with the study of the transposition of two EU Anti-discrimination directives in Austria. There, transposition had to overcome two types of conflict. On the one hand, a policy legacy diametrically opposed to anti-discrimination; on the other hand, an actor constellation ideologically contrary to anti-discrimination law. Based on the empirical material presented here, the paper suggests a number of strategies on how to further extant theoretical contributions in the field of transposition studies. [ABSTRACT FROM AUTHOR]

An analysis is performed on the molecular and electronic features in a series of trigonal molecules constituted by a central truxene core which is ramified with three oligofluorene moieties of different lengths. Arms and core are studied independently and upon threefold unification. Special emphasis is paid to the modulation of the conjugational properties in relation to substitution, molecular dimension, ring aromaticity, intermolecular forces, oxidation state, etc. Raman and optical absorption/emission spectroscopies in conjunction with computational theoretical results are combined for this purpose. The evolution of some key intensity ratios in the Raman spectra (i.e., I1300/I1235) is followed as an indication of electronic interaction between the core and the branches. The changes of the electronic delocalization upon solvation, with varying temperature in the solid state, with the nature of the aromatic unit (bithiophene/fluorene) or after electrochemical oxidation are interpreted. The modulation of the optical properties on the basis of the structure and energetics of the orbital around the gap is also addressed. Density functional theory was used to assign the vibrational and electronic spectra. [ABSTRACT FROM AUTHOR]

The molecular and electronic structures of a series of all-meta-substituted phenylacetylene mesitylenes peripherally substituted with donor or acceptor (D−A) groups are studied. The impact of meta- and para-substitution patterns is also analyzed by employing Raman and optical spectroscopies in conjunction with theoretical calculations. Outer phenyl rings display a partial quinoid character induced by two different motifs:  (i) outer phenyls → triple bond charge transfer for the cases where these phenyls are substituted with electron-donors; (ii) double electron withdrawing effect in the molecules with the peripheral phenyls substituted with electron acceptors. A moderate tuning of the optical gap is observed in agreement with the partial blockade of -electron conjugation exerted by the metadisposition. The orbital structure of the compounds partially preserves that of the mesitylene group showing extra-conjugation due to the addition of the arms, so that conjugation is not entirely obstructed but partially impeded in the ground electronic state (i.e., electron occupied orbitals). As for the excited states, the low-lying energy empty orbitals offer better conditions for full conjugation over the whole molecular scaffold. Interesting optical properties such as overlapping centers along the lowest energy optical excitations and enhanced optical transparency with importance for the application of these materials in optoelectronics have been justified on the basis of the electronic structure. A greater degree of quinoidization, and more allowed -electron delocalization, over the entire molecule is recognized in the case of linear phenylacetylenes substituting in parapositions the central core. [ABSTRACT FROM AUTHOR]

In this work, the interactions between heteroatoms (S, Se, and Te) and conjugated skeletons are analyzed. The study is carried out by using electronic absorption and fluorescence spectroscopies, electrochemistry, vibrational Raman spectroscopy, and theoretical calculations in the framework of DFT and TD−DFT theories. Optical spectra are described in terms of one-electron promotions between orbitals around the energy gap. Electrochemistry, in the framework of the Koopman's approach, is also interpreted. The vibrational Raman spectra are assigned to molecular modes and the evolution changing the heteroatom is addressed and an effective tuning of these properties is found. Part of this modulation is associated with local electronic interactions depending on the relative S, Se, and Te electronegativities. Unconventional long-range heteroatom−heteroatom interactions have been proposed which arise from the existence of effective π-conjugated channels. The molecular level understanding of structure−property relationships in these organic/inorganic semiconductors are of great interest in the interdisciplinary area of material science. [ABSTRACT FROM AUTHOR]

We consider a monotone operator of the form Au = -div(a(x, Du)), with Ω ⊆ Rn and a : Ω x MM x N → MM x N, acting on W1, p 0 (Ω, RM). For every sequence (Ωh) of open subsets of Ω and for every ƒ ∈ W-1, p′ (Ω, RM), 1/p+1/p′ = 1, we study the asymptotic behavior, as h !→ +&infini;, of the solutions uh ∈ W¹ 0 (Ωh, RM) of the systems Auh = ƒ in W-1, p′ (Ωh, RM), and we determine the general form of the limit problem. [ABSTRACT FROM AUTHOR]

Oligothiophene-substituted 1,1,4,4-tetracyanobutadienes (TCBDs) have been synthesized by [2 2] cycloaddition reactions between tetracyanoethylene and oligothiophene alkynes. The TCBD moiety is compared to other electron acceptors attached to dibutylterthiophene including dicyanovinyl (DCV) and tricyanovinyl (TCV). These donor−acceptor molecules (TCBD-3T, DCV-3T, and TCV-3T) show red-shifted absorption spectra relative to the unsubstituted oligothiophene as a result of intramolecular charge-transfer (ICT). Monosubstituted terthiophenes bearing the electron acceptors show both oxidation and reduction processes as characterized by cyclic voltammetry. Density functional theory (DFT) calculations are used to explain the electronic and redox properties of the materials. Electrochemical oxidation of a bis(terthienyl)-substituted TCBD molecule (3T-TCBD-3T) yields a conducting polymer exhibiting balanced ambipolar redox conduction with similar values for the oxidized and reduced states of the polymer (1 × 10−3S cm−1). Raman spectra of the asymmetric donor−acceptor materials are characterized by two intense bands characteristic of the aromatic and quinoidal regions in the conjugated π-system of the oligothiophene. [ABSTRACT FROM AUTHOR]

While the chemistry of open-shell singlet diradicaloids has been successfully developed in recent years, the synthesis of π-conjugated systems with poly-radical characters (i.e., beyond diradical) in the singlet ground state has been mostly unsuccessful. In this study, we report the synthesis and isolation of two fully fused macrocycles containing four (4MC) and six (6MC) alternatingly arranged quinoidal/aromatic carbazole units. Ab initio electronic structure calculations and various experimental measurements indicate that both 4MC and 6MC have an open-shell singlet ground state with moderate tetraradical and hexaradical characters, respectively. Both compounds can be thermally populated to high-spin excited states, resulting in weak magnetization at room temperature. Our study represents the first demonstration of singlet π-conjugated molecules with poly-radical characters and also gives some insights into molecular magnetism in neutral π-conjugated polycyclic heteroarenes. [ABSTRACT FROM AUTHOR]

p-Quinodimethane (p-QDM) is a fundamental building block for the design of p-conjugated systems with low band gap and open-shell biradical character. However, synthesis of extended p-QDMs has usually suffered from their intrinsic high reactivity and poor solubility. In this work, benzannulation together with terminal cyano-substitution was demonstrated to be an efficient approach for the synthesis of a series of soluble and stable tetracyano-oligo(N-annulated perylene)quinodimethanes nPer-CN (n = 1-6), with the longest molecule having 12 para-linked benzenoid rings! The geometry and electronic structures of these oligomers were investigated by steady-state and transient absorption spectroscopy, nuclear magnetic resonance, electron spin resonance, superconducting quantum interference device, and FT Raman spectroscopy assisted by density functional theory calculations. They showed tunable ground states, varying from a closed-shell quinoidal structure for monomer, to a singlet biradical for dimer, trimer, and tetramer, and to a triplet biradical for pentamer and hexamer. Large two-photon absorption cross-section values were observed in the near-infrared range, which also exhibited a clear chain-length dependence. [ABSTRACT FROM AUTHOR]

Stable open-shell polycyclic aromatic hydrocarbons (PAHs) are of fundamental interest due to their unique electronic, optical, and magnetic properties and promising applications in materials sciences. Chichibabin's hydrocarbon as a classical open-shell PAH has been investigated for a long time. However, most of the studies are complicated by their inherent high reactivity. In this work, two new stable benzannulated Chichibabin's hydrocarbons 1-CS and 2-OS were prepared, and their electronic structure and geometry in the ground state were studied by various experiments (steady-state and transient absorption spectra, NMR, electron spin resonance (ESR), superconducting quantum interference device (SQUID), FT Raman, X-ray crystallographic etc.) and density function theory (DFT) calculations. 1-CS and 2-OS exhibited tunable ground states, with a closed-shell quinoidal structure for 1-CS and an open-shell biradical form for 2-OS. Their corresponding excited-state forms 1-OS and 2-CS were also chemically approached and showed different decay processes. The biradical 1-OS displayed an unusually slow decay to the ground state (1-CS) due to a large energy barrier (95 ±± 2.5 kJ/mol) arising from severe steric hindrance during the transition from an orthogonal biradical form to a butterfly-like quinoidal form. The quick transition from the quinoidal 2-CS (excited state) to the orthogonal biradicaloid 2-OS (ground state) happened during the attempted synthesis of 2-CS. Compounds 1-CS and 2-OS can be oxidized into stable dications by FeCl3 and/or concentrated H2SO4. The open-shell 2-OS also exhibited a large two-photon absorption (TPA) cross section (760 GM at 1200 nm). [ABSTRACT FROM AUTHOR]

The poly(isocyanide) skeleton is shown to be a good support for assemblies of molecular units which permit p-type charge transport. A poly(isocyanide) containing tetrathiafulvalene (TTF) moieties in the side chains has been synthesized and characterized in its neutral state and has been oxidized to generate mixed valence states which display charge mobility in solution. UV−vis−NIR, EPR, and Raman spectroscopies were used to study the electronic properties of the polymer in its doped states, which were generated chemically with different oxidants. A broad charge-transfer band at 2100 nm characteristic of mixed valence agglomerations of neutral and cation radical TTFs was shown at lower doping levels, while evidence of aggregates between radical cation and the dicationic form of the heterocyclic system were seen at higher degrees of oxidation. The neutral macromolecule, the first mixed valence state, and the cation radical system can be reversibly interconverted by alternate oxidation with Fe(ClO4)3and subsequent reduction with triethylamine, and therefore the material can be considered as a candidate for electrochromic switches. EPR measurements reveal magnetic interactions between cation radical TTF moieties as well as indication of charge delocalization over the macromolecule. Bearing in mind the steric impediment that the alkyl chains attached to the TTF unit provide, we conclude that the results suggest that the motion of the charges in the first mixed valence state is intramacromolecular:  this hypothesis implies that there are interactions of the TTF residues in the side chains of the polymer which lead to a stack of the -functional units, confirming the affirmation that this polymer skeleton is appropriate for appending electron-conducting stacks of -functional units. [ABSTRACT FROM AUTHOR]