The effects of environmental information provision on plastic bag use and marine environment status in the context of the environmental levy in Greece.

The focus of this study is to examine the level of awareness, as well as the impacts of environmental information provision, regarding plastic bag consumption in Greece, taking into consideration the effects of plastic pollution in the marine environment within the framework of the environmental levy. This study was conducted through the use of two structured questionnaires as web-based surveys. The aim of both questionnaires was to explore citizen attitudes towards the marine environment in addition to their preferences with regard to the implementation of a program aimed at marine conservation and the reduction of plastic bag use. Data on plastic bag consumption at a national level were also incorporated. This research was carried out according to the contingent valuation method aimed at estimating citizen willingness-to-pay (WTP) on both structured questionnaires. The first questionnaire utilized the minimal legal WTP (ML-WTP) model resulting in 834 responses in total, while the second questionnaire applied a double-bounded dichotomous choice method and amassed 713 responses in aggregate. Based on the results of the first questionnaire, pre-existing environmentally friendly behaviour was further enhanced by the introduction of the environmental levy on plastic bags. The second questionnaire revealed that marine conservation is based both on collective as well as individual responsibility. This study provides evidence that the utilization of both economic and non-economic measures may be very effective in considerably reducing plastic bag consumption and its detrimental impact on the marine environment.

A quasi-plane IrB18- cluster with high stability.

The structural evolution of neutral and anionic iridium-doped boron (B) clusters, IrBn0/- with n = 10-20, has been studied by the Crystal structure AnaLYsis by Particle Swarm Optimization (CALYPSO) method and density functional theory (DFT) calculations. The IrB18- cluster with a quasi-plane structure and high stability is uncovered. Molecular orbital (MO) and adaptive natural density partitioning (AdNDP) analyses indicate that the high stability of the IrB18- cluster is attributed to the strong covalent interactions between the 5d orbitals of the Ir atom and the 2p orbitals of the surrounding B atoms. The present results offer new insights and considerably extend our understanding of the structural evolution and electronic properties of other metal-doped B clusters.

Modeling of interaction induced polarizability of H2-H, numerical analysis.

The main effort in this study is focused on devising a numerical model procedure capable of providing reliable values of collisionally induced microscopic properties of importance in processes of light radiation interactions with molecular media. Special attention is devoted to the anisotropic polarizability of the weakly bound H2-H compounds, although broader applicability of the routines proposed is anticipated as well. To this end, Cartesian components of the collision-induced anisotropic polarizability, Δαij [-], are obtained for the L- (linear, 0°), S- (45°), and T-shape (90°) configurations of the supermolecular systems. The quantum chemistry ab initio numerical method is applied to determine the values of the quantities within the range of the separations between H2 and H moieties reaching 3 < R < 20 bohrs. This approach is then combined with long-range approximate computing routines in order to formulate an overall uniform modeling algorithm including the influence of the exchange, dispersion, and induction interactions on the collisional induced (CI) effects. The validity and precision of the tool is thoroughly assessed. The polarizabilities are then transformed so as to be expressed in terms of the so-called symmetry adapted (SA) components of the spherical tensor representation, ΔαλL (2). Applicability of the modeling scheme is evidenced with regard to the effective evaluation of symmetry adapted parameters for an extended range of intramolecular angularities, separations, and indices. The importance of the procedure for foreseeable CI spectral profile analyses is discussed.

Collision-induced absorption in Ar-Kr gas mixtures: A molecular dynamics study with new potential and dipole data.

We have implemented a scheme for classical molecular dynamics simulations of collision-induced absorption. The program has been applied to a gas mixture of argon (Ar) and krypton (Kr). The simulations are compared with accurate quantum dynamical calculations. The comparisons of the absorption coefficients show that classical molecular dynamics is correct within 10% for photon wave numbers up to 220 cm-1 at a temperature of 200 K for this system. At higher temperatures, the agreement is even better. Molecular dynamics accounts for many-body interactions, which, for example, give rise to continuous dimer formation and destruction in the gas. In this way, the method has an advantage compared with bimolecular classical (trajectory) treatments. The calculations are carried out with a new empirical Ar-Kr pair potential. This has been obtained through extensive analysis of experimental thermophysical and transport properties. We also present a new high level ab initio Ar-Kr potential curve for comparison, as well as ab initio interaction-induced dipole curves computed with different methods. In addition, the Ar-Kr polarizability and hyperpolarizability are reported. A comparison of the computed absorption spectra with an experiment taken at 300 K shows satisfactory agreement although a difference in absolute magnitude of 10%-15% persists. This discrepancy we attribute mainly to experimental uncertainty.

Structural Stability and Evolution of Medium-Sized Tantalum-Doped Boron Clusters: A Half-Sandwich-Structured TaB12- Cluster.

Transition-metal (TM)-doped boron clusters have received considerable attention in recent years, in part, because of their remarkable size-dependent structural and electronic properties. However, the structures of medium-sized boron clusters doped with TM atoms are still not well-known because of the much increased complexity of the potential surface as well as the rapid increase in the number of low-energy isomers, which are the challenges in cluster structural searches. Here, by means of an unbiased structure search, we systematically investigated the structural evolution of medium-sized tantalum-doped boron clusters, TaBn0/- (n = 10-20). The results revealed that TaBn0/- (n = 10-15) clusters adopt half-sandwich molecular geometries, with the notable exception of TaB10-, while for n = 16-18 and 19-20, the lowest-energy clusters are characterized by drum-type geometries and tubular molecules with two B atoms on the top, respectively. Good agreement between the calculated and experimental photoelectron spectra strongly support the validity of our global minimum structures. Molecular orbital and adaptive natural density partitioning analyses indicate that the enhanced stability of half-sandwich TaB12- is due to the strong interaction of the Ta atom (5d orbitals) with surrounding B atoms (2p orbitals) and σ B-B bonds in the B12 moiety.

Probing the low-energy structures of aluminum-magnesium alloy clusters: a detailed study.

The effect of Mg doping on the growth behavior and the electronic properties of aluminum clusters has been investigated theoretically using the CALYPSO (Crystal structure AnaLYsis by Particle Swarm Optimization) method in combination with density functional theory calculations. Compared to pure aluminum clusters, the structure of Mg-doped clusters shows the charming transformation with increasing atomic number. The photoelectron spectra (PES) of the global minima of anionic Aln and AlnMg (n = 3-20) clusters have been calculated based on the time-dependent density functional theory (TD-DFT) method. The reliability of our theoretical methodology is easily corroborated by the good agreement between the experimental PES and the simulated spectra. Our findings bring forth an ionic bonding with enhanced stability for the Al6Mg cluster, paired with a surprisingly large HOMO-LUMO gap, as would be expected from the magic number of 20 valence electrons.

Synthesis and antiproliferative activity of two diastereomeric lignan amides serving as dimeric caffeic acid-l-DOPA hybrids.

Two new diastereomeric lignan amides (4 and 5) serving as dimeric caffeic acid-l-DOPA hybrids were synthesized. The synthesis involved the FeCl3-mediated phenol oxidative coupling of methyl caffeate to afford trans-diester 1a as a mixture of enantiomers, protection of the catechol units, regioselective saponification, coupling with a suitably protected l-DOPA derivative, separation of the two diastereomers thus obtained by flash column chromatography and finally global chemoselective deprotection of the catechol units. The effect of hybrids 4 and 5 and related compounds on the proliferation of two breast cancer cell lines with different metastatic potential and estrogen receptor status (MDA-MB-231 and MCF-7) and of one epithelial lung cancer cell line, namely A-549, was evaluated for concentrations ranging from 1 to 256µM and periods of treatment of 24, 48 and 72h. Both hybrids showed interesting and almost equipotent antiproliferative activities (IC50 64-70µM) for the MDA-MB-231 cell line after 24-48h of treatment, but they were more selective and much more potent (IC50 4-16µM) for the MCF-7 cells after 48h of treatment. The highest activity for both hybrids and both breast cancer lines was observed after 72h of treatment (IC50 1-2µM), probably as the result of slow hydrolysis of their methyl ester functions.

Effects of anisotropic interaction-induced properties of hydrogen-rare gas compounds on rototranslational Raman scattering spectra: Comprehensive theoretical and numerical analysis.

A comprehensive study is presented of many aspects of the depolarized anisotropic collision induced (CI) component of light scattered by weakly bound compounds composed of a dihydrogen molecule and a rare gas (Rg) atom, H2-Rg. The work continues a series of earlier projects marking the revival of interest in linear light scattering following the development of new highly advanced tools of quantum chemistry and other theoretical, computational, and experimental means of spectral analyses. Sophisticated ab initio computing procedures are applied in order to obtain the anisotropic polarizability component's dependence on the H2-Rg geometry. These data are then used to evaluate the CI spectral lines for all types of Rg atoms ranging from He to Xe (Rn excluded). Evolution of the properties of CI spectra with growing polarizability/masses of the complexes studied is observed. Special attention is given to the heaviest, Kr and Xe based, scatterers. The influence of specific factors shaping the spectral lines (e.g., bound and metastable contribution, potential anisotropy) is discussed. Also the share of pressure broadened allowed rotational transitions in the overall spectral profile is taken into account and the extent to which it is separable from the pure CI contribution is discussed. We finish with a brief comparison between the obtained results and available experimental data.

Synthesis and biological evaluation of new C-10 substituted dithranol pleiotropic hybrids.

Selective alkylation of the antipsoriatic drug dithranol (DTR) at C-10 with tert-butyl bromoacetate, followed by acid-mediated deprotection, produced the corresponding carboxylic acid 4 which was coupled with selectively protected polyamines (PAs), such as putrescine (PUT), spermidine (SPD) and spermine (SPM), dopamine and aliphatic amines and substituted benzylamines producing a series of DTR-PA hybrids, after acid-mediated deprotection, as well as simple amides. The compounds were tested as antioxidants and inhibitors of lipoxygenase (LOX). The amides 4,4'-dimethoxybenzhydrylamide 13 (86% and 95%), 2,4-dimethoxybenzylamide 12 (87% and 81%) and dodecylamide 9 (98% and 74%), and the hybrid DTR-SPM (7) (93% and 87%), showed the highest antioxidant activity in the DPPH and AAPH assays, whereas the most potent inhibitors of LOX were amide 13 (IC50=7 µM), the benzylamide 10 (IC50=7.9 µM) and the butylamide 8 (IC50=10 µM). Molecular binding studies showed that binding of these derivatives into the hydrophobic domain blocks approach of substrate to the active site, inhibiting soybean LOX. Amide 13 presented the highest anti-inflammatory activity (79.7%). The DTR moiety was absolutely necessary for securing high anti-inflammatory potency. Ethyl ester 3 (IC50=0.357 µM) and the amides 9 (IC50=0.022 µM) and 13 (IC50=0.56 µM) exhibited higher antiproliferative activity than DTR (IC50=0.945 µM) on HaCaT keratinocytes whereas amide 13 generally presented better cytocompatibility. Amide 13 is a very promising lead compound for further development as an anti-inflammatory and antiproliferative agent.

Geometries, stabilities and fragmental channels of neutral and charged sulfur clusters: Sn(Q) (n = 3-20, Q = 0, ±1).

We have performed unbiased searches for the global minimum structures of neutral and charged sulfur clusters Sn(Q) (n = 3-20, Q = 0, ±1) relying on the CALYPSO structure searching method combined with density functional theory geometric optimization. Very accurate ab initio calculations are used to determine relative stabilities and energy ranking among competing low-lying isomers of the neutral and charged sulfur clusters obtained from the structure search. The harmonic vibrational analysis is also undertaken to assure that the optimized geometries are the true minima. It is shown that the most equilibrium geometries of sulfur clusters are closed three-dimensional (3D) helical rings, which is in agreement with the experimental observations. The binding energies, second-order energy differences, and highest occupied-lowest unoccupied molecular orbital (HOMO-LUMO) gaps of the considered species are calculated and analyzed systematically. Additionally, the fragmentation channels are determined and the results indicate that the Sn(Q) → S2 + Sn-2(Q) channel is a route that the small clusters (n = 3-10) favor, while the larger species (n = 13-20) prefer the Sn(Q) → S8 + Sn-8(Q) channel.

Intermolecular polarizabilities in H2-rare-gas mixtures (H2-He, Ne, Ar, Kr, Xe): insight from collisional isotropic spectral properties.

The report presents results of theoretical and numerical analysis of the electrical properties related to the isotropic part of the polarizability induced by interactions within compounds built up of a hydrogen H2 molecule and a set of noble gas atoms, Rg, ranging from the least massive helium up to the heaviest xenon perturber. The Cartesian components of the collisional polarizabilities of the H2-Rg systems are found by means of the quantum chemistry methods and their dependence on the intermolecular distance is determined. On the basis of these data, the spherical, symmetry adapted components of the trace polarizability are derived in order to provide data sets that are convenient for evaluating collisional spectral profiles of the isotropic polarized part of light scattered by the H2-Rg mixtures. Three independent methods of numerical computing of the spectral intensities are applied at room temperature (295 K). The properties of the roto-translational profiles obtained are discussed in order to determine the role played by contributions corresponding to each of the symmetry adapted parts of the trace polarizability. By spreading the analysis over the collection of the H2-Rg systems, evolution of the spectral properties with the growing masses of the supermolecular compounds can be observed.

Morphology of collisional nonlinear spectra in H2-Kr and H2-Xe mixtures.

This article reports new results of theoretical and numerical studies of spectral features of the collision-induced hyper-Rayleigh light scattered in dihydrogen-noble gas (H2-Rg) mixtures. The most massive and polarizable scattering supermolecules with Rg = Kr and Xe have been added to the previously considered systems in order to gain a more complete insight into the evolution of the spectral properties. The symmetry adapted components of the first collisional hyperpolarizabilities are obtained by means of the quantum chemistry numerical routines supplemented with appropriate theoretical methods. Roto-translational spectral lines are calculated on the grounds of the quantum-mechanical as well as semi-classical approach. The role of particular hyperpolarizability components in forming the line shapes is discussed. The intensities of the lines are compared with those obtained for less massive scatterers. Advantages of prospective application of the new scattering systems for experimental detection of the nonlinear collisional effects are indicated.

Interaction electric hyperpolarizability effects in weakly bound H(2)O...Rg (Rg = He, Ne, Ar, Kr and Xe) complexes.

We report an extensive high-level ab initio theoretical investigation of the interaction electric properties of the weakly bound complexes of water with rare gases, H(2)O...Rg (Rg = He, Ne, Ar, Kr and Xe). Our approach relies on finite-field many-body perturbation theory (MP) and coupled-cluster (CC) calculations with flexible, carefully designed basis sets of Gaussian-type functions (GTFs). We have obtained estimates of the electron correlation effects on the reference self-consistent field (SCF) values at all levels of theory employed in this work. For the planar equilibrium configuration (C(s) symmetry) of the complexes, at the CCSD(T) level of theory, the interaction mean first hyperpolarizability is positive (SCF values in parentheses): beta(int)/e(3)a(0)(3)E(h)(-2)(H(2)O-Rg) = 0.72 (0.56), 1.20 (0.79), 7.04 (4.28), 9.88 (5.34), and 15.52 (6.68) for Rg = He, Ne, Ar, Kr, and Xe, respectively. For the interaction mean second hyperpolarizability, we have obtained (SCF values in parentheses): gamma(int)/e(4)a(0)(4)E(h)(-3)(H(2)O-Rg) = -18.93 (-14.19), -37.78 (-24.35), -83.16 (-72.42), -102.92 (-125.70), and -206.45 (-286.83) for Rg = He, Ne, Ar, Kr, and Xe. In addition to the equilibrium values of the interaction electric properties, we have also extracted information for their dependence on the variation of the distance of the rare gas atom from the center of mass of the water molecule (without changing direction). The gradient of the interaction mean second hyperpolarizability at the equilibrium configuration is determined as (dgamma(int)/dR)(e)/e(4)a(0)(3)E(h)(-3)(H(2)O-Rg) = 9.89 (He), 25.42 (Ne), 73.71 (Ar), 144.71 (Kr), and 324.68 (Xe).

Relation between first trimester maternal serum leptin levels and body mass index in normotensive and pre-eclamptic pregnancies--role of leptin as a marker of pre-eclampsia: a prospective case-control study.

OBJECTIVE: We measured first trimester plasma leptin concentrations in 37 women who subsequently developed pre-eclampsia and 53 normotensive controls to determine the interrelation between leptin and body mass index (BMI) in both groups. We further investigated the association between the risks for pre-eclampsia with maternal leptin levels. METHODS: Bloods samples were collected at 13 weeks. Non-parametric tests, Spearman's correlation, linear regression analysis and multiple logistic regression analysis were applied in our data. RESULTS: 1 kg/m(2) increase in pre-pregnancy BMI was related to a 2.747 (95% CI: 3.242-2.252) ng/ml rise in leptin concentration among cases and 2.502 (95% CI: 2.873-2.131) ng/ml rise in leptin concentrations among controls. Increased leptin concentration (>or=25.3 ng/ml ) in lean women is associated with a 18.8-fold increased risk of pre-eclampsia (adjusted OR: 18.8, CI: 1.8-194, p = 0.014 ). Leptin treated as a continuous variable is a significant predictor of pre-eclampsia (adjusted OR: 1.08, CI: 1.018-1.133, p = 0.009). CONCLUSION: Increased leptin concentration can definitely contribute to the prediction of pre-eclampsia in lean women, but this is not the case in overweight women. Further research in terms of longitudinal case-control studies is required to clarify the predictive value of pre-eclampsia.

Probing the structure and electronic properties of beryllium doped boron clusters: A planar BeB16- cluster motif for metallo-borophene.

Beryllium-doped boron clusters display essential similarities to borophene (boron sheet) with a molecular structure characterized by remarkable properties, such as anisotropy, metallicity and high conductivity. Here we have determined low-energy structures of BeBn0/- (n = 10-20) clusters by utilizing CALYPSO searching program and DFT optimization. The results indicated that most ground states of clusters prefer plane or quasi-plane structures by doped Be atom. A novel unexpected fascinating planar BeB16- cluster with C2v symmetry is uncovered which possesses robust relative stability. Furthermore, planar BeB16- offers a possibility to construct metallo-borophene nano-materials. Molecular orbital and chemical bonding analysis reveal the peculiarities of BeB16- cluster brings forth the aromaticity and the strong interaction of B-B σ-bonds in boron network.

How large is the static electric (hyper)polarizability anisotropy in HXeI?

An extensive conventional ab initio and density functional theory investigation reveals that HXeI is a polar molecule with large multipole moments and highly anisotropic (hyper)polarizability. At the CCSD(T) level of theory our best values for the mean (hyper)polarizability are alphae(2)a(0) (2)E(h) (-1)=101.46, betae(3)a(0) (3)E(h) (-2)=-850.7, and gammae(4)a(0) (4)E(h) (-3)=18.7x10(3). The corresponding anisotropies are Deltaalphae(2)a(0) (2)E(h) (-1)=119.66, Deltabetae(3)a(0) (3)E(h) (-2)=-2518.7, Delta(1)gammae(4)a(0) (4)E(h) (-3)=-249.1x10(3), and Delta(2)gammae(4)a(0) (4)E(h) (-3)=-99.6x10(3). The longitudinal components of the (hyper)polarizability are dominant. Our value for the anisotropy of the dipole polarizability is considerably larger than the recent empirical estimate of 22.9 e(2)a(0) (2)E(h) (-1) [N. H. Nahler et al., J. Chem. Phys. 119, 224 (2003)]. The results of the insertion of Xe into HI are quantified by the calculation of the differential (hyper)polarizability at the MP2 level of theory: alpha(diff) identical withalpha(HXeI)-alpha(HI)-alpha(Xe)=36.29 e(2)a(0) (2)E(h) (-1) and gamma(diff) identical with gamma(HXeI)-gamma(HI)-gamma(Xe)=18.1x10(3) e(4)a(0) (4)E(h) (-3).

Collision-induced hyper-Rayleigh spectrum of H(2)-Ar gas mixture.

The collision-induced hyper-Rayleigh (CIHR) spectra of the gaseous H(2)-Ar mixture are discussed in the binary regime on the basis of our ab initio computed H(2)-Ar collision-induced (CI) first dipole hyperpolarizability tensor Deltabeta(R). A method for the computation of the spherical, rotationally adapted components Deltabeta(lambdaL) ((s,K))(R) of Deltabeta(R) needed for spectroscopic line shape analysis is proposed. Both the vector and the septor parts of the H(2)-Ar CIHR spectrum are evaluated at room (T=295 K) temperature. The spectra are calculated assuming the full quantum computations based on the Schrodinger equation of the relative translational motion of H(2)-Ar as well as semiclassical methods (classical trajectory approach and Birnbaum-Cohen model translational profiles). The H(2)-Ar pair CIHR septor spectrum has been found stronger than the vector one.

Interaction-induced electric (hyper)polarizability in the dihydrogen-neon pair: basis set and electron correlation effects.

We investigated the interaction (hyper)polarizability of neon-dihydrogen pairs by performing high-level ab initio calculations with atom/molecule-specific, purpose-oriented Gaussian basis sets. We obtained interaction-induced electric properties at the SCF, MP2, and CCSD levels of theory. At the CCSD level, for the T-shaped configuration, around the respective potential minimum of 6.437 a0, the interaction-induced mean first hyperpolarizability varies for 5 <  R/a0 < 10 as[Formula: see text]Again, at the CCSD level, but for the L-shaped configuration around the respective potential minimum of 6.572 a0, this property varies for 5 <  R/a0 < 10 as[Formula: see text] Graphical Abstract Interaction-induced mean dipole polarizability ([Formula: see text]) for the T-shaped configuration of H2-Ne calculated at the SCF, MP2, and CCSD levels of theory.

Probing the Structural and Electronic Properties of Dirhenium Halide Clusters: A Density Functional Theory Study.

Dirhenium halide dianions received considerable attention in past decades due to the unusual metal-metal quadruple bond. The systematic structural evolution of dirhenium halide clusters has not been sufficiently studied and hence is not well-understood. In this work, we report an in-depth investigation on the structures and electronic properties of doubly charged dirhenium halide clusters Re2X82- (X = F, Cl, Br, I). Our computational efforts rely on the well-tested unbiased CALYPSO (Crystal structure AnaLYsis by Particle Swarm Optimization) method combined with density functional theory calculations. We find that all ground-state Re2X82- clusters have cube-like structures of D4h symmetry with two Re atoms encapsulated in halogen framework. The reasonable agreement between the simulated and experimental photoelectron spectrum of the Re2Cl82- cluster supports strongly the reliability of our computational strategy. The chemical bonding analysis reveals that the δ bond is the pivotal factor for the ground-state Re2X82- (X = F, Cl, Br, I) clusters to maintain D4h symmetric cube-like structures, and the enhanced stability of Re2Cl82- is mainly attributed to the chemical bonding of 5d orbital of Re atoms and 3p orbital of Cl atoms.

Preimplantation genetic diagnosis.

Preimplantion genetic diagnosis (PGD) is now used for identification of gene and chromosomal defects in embryos. In this article we describe its use primarily for identification of chromosomal defects in women with recurrent abortions, repeated in vitro fertilization (IVF) failure, and advanced maternal age. In all these situations there is increase in chromosomal defects. The identification of normal embryos and the elimination of abnormal embryos are argued to be helpful in increasing implantation and pregnancy rates in these women.