Health literacy and physical activity as buffers to counter act work related stress

Background

Stress health problems affect 47.8% of the work force in Portugal. It is predicted that, in the next decade, these problems will overcome musculoskeletal disorders, the first cause of employee’s withdrawal from work. Research indicates connections between stress and dimensions of the work place (like job satisfaction). Nevertheless the conceptual understanding of these relationships is sparse. In order to better understand these relationships, this research focus on the use of job–specific models of stress, associating them with health literacy (HL) - in the context of the European Health Literacy Survey framework (HLS-EU) - and physical exercise.

Methods

A total of 748 participants from the different offices of a company in the financial sector (Portugal, main land and autonomous territories) participated in a cross sectional survey (CAWI). Age ranged from 25 to 65 years and HL was measured using the HLS-EU instrument validated to Portuguese (HLS-EU-PT). Each participant was allocated to one of the groups, either of satisfactory HL (when scores ≥30) or insufficient HL (when scores <30).

Results

Out of the 748 participants (58.7% males, average age of 39 years), 80.4% sometimes and very often experience stress and tension in the workplace. Less than one in every two (44.4%) practice physical activity several times a week. Of the participants, 7.1% have inadequate, 39.0% problematic, 36.6% sufficient and 17.3% excellent HL (HLS-EU-PT). Employees that are more active are those who experience lower levels of stress.

Conclusions

The research of the effects of HL combined with physical exercise, as buffer variables to problems related to the effects of work stress, is a new area of research that may help understand patterns of adherence to activities that can help workers deal with everyday working conditions. More research is needed to integrate HL strategies in the work place.

Topochemical nitridation of Sr2FeMoO6

The topotactic nitridation of cation ordered, tetragonal Sr2FeMoO6 in NH3 at moderate temperatures leads to cubic, Fm3[combining macron]m double perovskite oxynitride Sr2FeMoO4.9N1.1 where double-exchange interactions determine ferromagnetic order with TC ≈ 100 K. Substitution of oxide by nitride induces bond asymmetries and local electronically driven structural distortions, which combined with Fermi level lowering restricts charge itinerancy to confined regions and preclude spontaneous long-range magnetic order. Under a magnetic field, ferromagnetic correlations expand, favoring charge delocalization and a negative magnetoresistance is observed.

Energetic, Topological and Electric Field Analyses of Cation-Cation Nucleic Acid Interactions in Watson-Crick Disposition

A theoretical study of the effect of the diprotonation on the nucleic acid bases (A : U, A : T and G : C) in Watson-Crick conformation has been carried out by means of DFT computational methods in vacuum. In addition, the corresponding neutral and monoprotonated binary complexes have been considered. Most of the diprotonated species studied are stable, even though the binding energy is positive due to the overall repulsive electrostatic term. Local electrostatic attractive forces in the regions of hydrogen bonds (HBs) are responsible for equilibrium geometries, as shown by the electric field lines connecting the electrophilic and nucleophilic sites involved in the HB interactions. Secondary electrostatic effects also affect the assembling of the nucleic acid complexes in either neutral or cationic form. In particular, the electric field lines flowing from electrophilic sites in one base to nucleophilic sites in the other reinforce the linking between them. Hence, when the nucleophilic site concerns the free lone pair of the heteroatom involved in the HB interaction as acceptor, the HB distance shortens. However, if the free lone pair of the HB acceptor interacts with an electrophilic site in the same molecule, the HB distance elongates, weakening the HB interaction. The topological analysis of the electron density distribution in HB regions indicates that neutral, monoprotonated and diprotonated complexes show no differences in the nature of their HB's.

Synthesis of Au Nanoparticles Assisted by Linker-Modified TiO2 Nanoparticles

Plasmonic nanoparticles, especially gold ones, have been widely employed as photosensitizers in photoelectrovoltaic or photocatalytic systems. To improve the system's performance, a greater interaction of the nanoparticles with the semiconductor, generally TiO₂, is desired. Moreover, this performance is enhanced when an efficient covering of TiO₂ surface by the sensitizer is achieved. The Brust-Schiffrin-like methods are of the most employed approaches for nanoparticles synthesis. In a traditional approach, the reduction of the gold precursor is performed in the presence of a stabilizer (typically a thiol molecule) free in solution. A second step in which the obtained nanoparticles are anchored to the semiconductor surface is necessary in the case of photosensitive applications. Drawbacks like steric hindrance turn more difficult the covering of the semiconductor's surface by nanoparticles. In this paper, we report a variation of this methodology, where the linker is previously anchored to the TiO₂ nanoparticles surface. The resulting system is employed as the stabilizer in the gold reduction step. This strategy is carried out in aqueous media in two simple steps. A great covering of the titania surface by gold nanoparticles is achieved in all cases and the gold nanoparticles in the resulting nanoaggregate might be useful for photoelectrovoltaic or photocatalytic applications.

Topochemical synthesis of cation ordered double perovskite oxynitrides

Sr₂FeWO_6−xN_x compounds with nitrogen contents up to x = 1 are prepared by topochemical ammonolysis of Sr₂FeWO₆. Sr₂FeWO₅N is antiferromagnetic with T_N = 13 K and represents the first double perovskite oxynitride with high cationic order and nitrogen content.

Charged versus Neutral Hydrogen-Bonded Complexes: Is There a Difference in the Nature of the Hydrogen Bonds?

A theoretical study on some carboxylic acid dimers formed by positively or negatively charged molecules has been carried out by using DFT methods. The resulting dimers possess either a charge of +2 or -2. In addition, the corresponding neutral complexes have also been considered. The electron density distribution described by the atoms in molecules and the natural bond orbital methods, as well as the electric field maps of the systems, have been analyzed and compared without finding significant differences between the neutral and ionic complexes. The interaction energy along the dissociation path of the charged dimers shows both a local minimum and a local maximum, defining a stability region between them. When this energetic profile is recalculated by removing the repulsion between the charged groups, it resembles to those of the neutral molecules. Hence, the characteristics of the charged dimers are similar to those of the neutral ones: the addition of a repulsion term for the charged groups permits to retrieve the energetic profiles dependence with the distance in the charged system. The interacting quantum atom (IQA) method has been used to calculate the interaction energy terms, including the classic Coulombic term between the whole molecules and the corresponding of the carboxylic acid groups. The IQA results show repulsive electrostatic interactions when the whole molecules are considered in the ionic complexes, but attractive ones between the carboxylic groups in both neutral and ionic complexes.

Tuning the structure and the mechanical properties of epoxy–silica sol–gel hybrid materials

A new epoxy–silica porous material prepared via one-pot sol–gel process. Mechanical properties can be continuously tuned by modifying reactant proportions.

The paradox of hydrogen-bonded anion-anion aggregates in oxoanions: a fundamental electrostatic problem explained in terms of electrophilic···nucleophilic interactions

A theoretical study of anionic complexes formed by two partly deprotonated oxoacids joined by hydrogen bonds has been carried out at the MP2 computational level. In spite of the ionic repulsion, local energy minima are found both in the gas phase and in aqueous solution. Electrostatic potential and electron density topologies, and the comparison with neutral complexes formed by oxoacids, reveal that the ionization has no significant effect on the properties of the hydrogen bonds. The stability of the complexes in the gas phase is explained by attractive forces localized in a volume situated in the hydrogen bond and defined as the electrostatic attraction region (EAR) and determined by the topological analyses of the electron density and the electrostatic potential, and by the electric field lines. In solution, the strong anionic repulsion is mostly screened by the effect of the surrounding polar solvent, which only leads to a weak destabilizing interaction in the hydrogen bond region and finally favors the overall stability of the complexes. The anion-anion complexes have been compared with the corresponding neutral ones (as salts or protonated forms), showing that EAR remains unchanged along the series.

Synthesis, X-ray characterization and DFT studies of bis-N-imidazolylpyrimidine salts: the prominent role of hydrogen bonding and anion–π interactions

Five new compounds have been synthesized and characterized by elemental analysis, IR, NMR and single-crystal X-ray diffraction. They present interesting assemblies in the solid state dominated by H-bonding and anion–π interactions.

C—H...X(X= O, N or π) interactions in benzyl carbamate

The crystal packing and interaction energy of benzyl carbamate, C8H9NO2, have been analysed in detail by thePIXELmethod. Benzyl carbamate forms layers of hydrogen-bonded molecules, with the layers connected by weaker C—H...π interactions. According to thePIXELanalysis, combinations of C—H...X(X= O, N or π) interactions are comparable in energy with hydrogen bonding. These interactions are necessary for explaining the geometry and the assembly of the layers.

Global and regional cortical thinning in first-episode psychosis patients: relationships with clinical and cognitive features

BACKGROUND

The thickness of the cortical mantle is a sensitive measure for identifying alterations in cortical structure. We aimed to explore whether first episode schizophrenia patients already show a significant cortical thinning and whether cortical thickness anomalies may significantly influence clinical and cognitive features.

METHOD

We investigated regional changes in cortical thickness in a large and heterogeneous sample of schizophrenia spectrum patients (n=142) at their first break of the illness and healthy controls (n=83). Magnetic resonance imaging brain scans (1.5 T) were obtained and images were analyzed by using brains2. The contribution of sociodemographic, cognitive and clinical characterictics was investigated.

RESULTS

Patients showed a significant total cortical thinning (F=17.55, d=-0.62, p<0.001) and there was a diffuse pattern of reduced thickness (encompassing frontal, temporal and parietal cortices) (all p's<0.001, d's>0.53). No significant group×gender interactions were observed (all p's>0.15). There were no significant associations between the clinical and pre-morbid variables and cortical thickness measurements (all r's<0.12). A weak significant negative correlation between attention and total (r=-0.24, p=0.021) and parietal cortical thickness (r=-0.27, p=0.009) was found in patients (thicker cortex was associated with lower attention). Our data revealed a similar pattern of cortical thickness changes related to age in patients and controls.

CONCLUSIONS

Cortical thinning is independent of gender, age, age of onset and duration of the illness and does not seem to significantly influence clinical and functional symptomatology. These findings support a primary neurodevelopment disorder affecting the normal cerebral cortex development in schizophrenia.

Universal features of the electron density distribution in hydrogen-bonding regions: a comprehensive study involving H...X (X=H, C, N, O, F, S, Cl, pi) interactions

Topological analyses of the theoretically calculated electron densities for a large set of 163 hydrogen-bonded complexes show that HX interactions can be classified in families according to X (X=atom or pi orbital). Each family is characterised by a set of intrinsic dependencies between the topological and energetic properties of the electron density at the hydrogen-bond critical point, as well as between each of them and the bonding distance. Comparing different atom-acceptor families, these dependencies are classified as a function of the van der Waals radius r(X) or the electronegativity chi(X), which can be explained in terms of the molecular orbitals involved in the interaction. According to this ordering, the increase of chi(X) leads to a larger range of HX distances for which the interaction is of pure closed-shell type. Same dependencies observed for HO interactions experimentally characterised by means of high-resolution X-ray diffraction data show a good agreement with those obtained from theoretical calculations, in spite of a larger dispersion of values around the expected fitting functions in the experimental case. Theoretical dependencies can thus be applied to the analysis of the experimental electron density for detecting either unconventional hydrogen bonds or problems in the modelling of the experimental electron density.

Effect of an external electric field on the dissociation energy and the electron density properties: The case of the hydrogen bonded dimer HF...HF

The effect of a homogeneous external electric field parallel to the hydrogen bond in the FH...FH dimer has been studied by theoretical methods. The quantum theory of atoms in molecules methodology has been used for analyzing the electron distribution of the dimer, calculated with different hydrogen bond distances and external field magnitudes. It is shown that an electric field in the opposite direction to the dipole moment of the system strengthens the interaction due to a larger mutual polarization between both molecules and increases the covalent character of the hydrogen bond, while an external field in the opposite direction has the inverse effect. The properties of the complex at its equilibrium geometry with applied field have been calculated, showing that dependencies between hydrogen bond distance, dissociation energy, and properties derived from the topological analysis of the electron distribution are analogous to those observed in families of XDH...AY complexes. The application of an external field appears as a useful tool for studying the effect of the atomic environment on the hydrogen bond interaction. In the case of FH...FH, both the kinetic energy density and the curvature of the electron density along the hydrogen bond at the bond critical point present a surprisingly good linear dependence on the dissociation energy. The interaction energy can be modeled by the sum of two exponential terms that depend on both the hydrogen bond distance and the applied electric field. Moreover, as indicated by the resulting interaction energy observed upon application of different external fields, the equilibrium distance varies linearly with the external field, and the dependence of the dissociation energy on either the hydrogen bond distance or the external electric field is demonstrated to be exponential.

Cannabis abuse is associated with decision-making impairment among first-episode patients with schizophrenia-spectrum psychosis

BACKGROUND

Cannabis use appears to be a risk factor for schizophrenia. Moreover, cannabis abusers show impaired decision-making capacities, linked to the orbitofrontal cortex (OFC). Although there is substantial evidence that first-episode schizophrenia patients show impairments in cognitive tasks associated with the dorsolateral prefrontal cortex (DLPFC), it is not clear whether decision making is impaired at schizophrenia onset. In this study, we examined the association between antecedents of cannabis abuse and cognitive impairment in cognitive tasks associated with the DLPFC and the OFC in a sample of first-episode patients with schizophrenia-spectrum disorders.

METHOD

One hundred and thirty-two patients experiencing their first episode of a schizophrenia-spectrum psychosis were assessed with a cognitive battery including DLPFC-related tasks [backward digits, verbal fluency (FAS) and the Trail Making Test (TMT)] and an OFC-related task [the Iowa Gambling Task (GT)]. Performance on these tasks was compared between patients who had and had not abused cannabis before their psychosis onset.

RESULTS

No differences were observed between the two groups on the performance of any of the DLPFC-related tasks. However, patients who had abused cannabis before their psychosis onset showed a poorer total performance on the gambling task and a lower improvement on the performance of the task compared to no-abusers.

CONCLUSIONS

Pre-psychotic cannabis abuse is associated with decision-making impairment, but not working memory and executive function impairment, among first-episode patients with a schizophrenia-spectrum psychosis. Further studies are needed to examine the direction of causality of this impairment; that is, does the impairment make the patients abuse cannabis, or does cannabis abuse cause the impairment?

Choline acetyltransferase variants and their influence in schizophrenia and olanzapine response

Choline acetyltransferase (ChAt) is extensively distributed throughout the CNS where, by catalyzing acetylcholine synthesis, it participates in modulating wide-ranging cholinergic-dependent functions including cognitive performance, sleep, arousal, movement, and visual information processing. Recently, compelling evidence has mounted implicating ChAt in schizophrenia. In particular, studies have identified significant reductions in ChAt activity in the nucleus accumbens and pontine tegmentum of such patients, which furthermore correlate significantly with measures of cognitive performance in the disorder. Similarly, elevated levels of choline, the acetylcholine precursor, have been identified among patients, implicating altered ChAt activity in these individuals. We sought to investigate the potential contribution of three ChAt gene polymorphisms in schizophrenia, and uncovered evidence for significant association between one of these, rs1880676G/A, and disease susceptibility among Basque individuals (genotypewise chi(2) = 20.7, P = 0.00003; allelewise chi(2) = 10.1, P = 0.002). A similar trend for association with susceptibility was observed for a second SNP, rs3810950G/A, (genotypwise chi(2) = 6.4, P = 0.05; allelewise chi(2) = 3.75, P = 0.05). Evidence was also uncovered for a potential influence of these polymorphisms on olanzapine treatment outcome among Spanish patients (F-statistic = 5.02, P = 0.03; F-statistic = 6.53, P = 0.02 respectively), and on improvements in positive symptoms in the case of rs3810950 (F-statistic = 5.3, P = 0.03) and general psychopathology in the case of rs1880676 and rs3810950 (F-statistic = 5.24, P = 0.03; F-statistic = 5.31, P = 0.03 respectively) during therapy. While more comprehensive studies are warranted to determine the precise contribution of ChAt mediated mechanisms in schizophrenia, our findings tentatively implicate a genetic influence of ChAt in the disorder's susceptibility and treatment.

Zero-flux surfaces of the electrostatic potential: the border of influence zones of nucleophilic and electrophilic sites in crystalline environment

The topology of the electrostatic potential varphi(r) has been studied for single molecules using geometries and electron distributions rho(r) determined from high-resolution single-crystal X-ray diffraction data. The electrostatic potential gradient nablavarphi(r), which is the negative of the electric field E = -nablavarphi, has been represented, revealing the position of zero-flux surfaces and critical points. Local maxima and minima of the electrostatic potential are interpreted in terms of electrophilic and nucleophilic sites, which present influence zones delimited by zero-flux surfaces containing saddle points. The influence zones of the nucleophilic and electrophilic sites define two alternative partitions of the space in disjoint volumes, the completeness of these partitions depending on either the neutral or ionic character of the molecule. The results obtained by using this methodology are useful for the interpretation of the saddle points of the electrostatic potential, which are related to the limits of the influence zones and reveal the path for preferred attack on reactive sites with finite influence zones.

Topological properties of the electrostatic potential in weak and moderate N...H hydrogen bonds

The topological analyses of the electrostatic potential phi(r) and the electron density distribution rho(r) have been performed for a set of 20 neutral complexes with weak and moderate N...H bonds. In all cases, a zero flux surface of the electrostatic potential containing a saddle point analogous to the bond critical point of the electron density distribution is observed. These surfaces define an equivalent of the atomic basin of rho(r) for the electrostatic potential, which exhibits zero net charge and can be regarded as an electrostatically isolated region if its volume is finite. The phi(r) and rho(r) zero flux surfaces divide the hydrogen-bonding region in three parts, being the central one related to the electrostatic interaction between donor and acceptor. This central region exhibits a relative size of approximately 13-14% of the N...H distance dNH, it belongs to the outermost shell of the nitrogen and is mainly associated with its lone pair. Topological properties of both rho(r) and phi(r), as well as the electron kinetic (G) and potential (V) energy densities, show similar dependences with dNH at both bond critical points (phi-BCP and rho-BCP). Phenomenological proportionalities between the rho(r) curvatures and G and V are also found at the electrostatic potential critical point. The curvatures of the electrostatic potential, which are interpreted in terms of the electrostatic forces in the bonding region, present the same exponential dependency as the electron density distribution, to which they are related by Poisson's equation.

No association between ADRA2A polymorphisms and schizophrenia

There is evidence to suggest that the alpha(2A)-adrenergic receptor may be involved in schizophrenia. With attention directed at the upstream regulatory region of the gene which codes for this receptor (ADRA2A), we proposed that single nucleotide polymorphisms (SNPs) within this region influences susceptibility to schizophrenia by altering the expression of this receptor. We opted to test for an influence on susceptibility by association study using 112 schizophrenic/schizoaffective disorder patients and 159 controls. The region of interest was screened for SNPs using a combination of bioinformatic searches and sequencing. A total of nine SNPs were discovered, of which four (-5972-G/A, -2211-A/T, -1291-C/G and -261-G/A) were genotyped in the entire clinical sample. No associations were evident, suggesting no influence for these SNPs in susceptibility to schizophrenia.

Synthesis and investigation of the boron cluster anion [7-(2′-pyridyl)-7,8-nido-dicarbaundecaborate] and its protonated form

The structurally chiral [7-(2'-pyridyl)-7,8-nido-C(2)B(9)H(11)](-), [](-), anion was prepared by a partial degradation reaction of 1-(2'-pyridyl)-1,2-closo-C(2)B(10)H(11). From this anion a protonated specie, H[7-(2'-pyridyl)-7,8-nido-C(2)B(9)H(11)] , and a tetramethylammonium salt, [NMe(4)][7-(2'-pyridyl)-7,8-nido-C(2)B(9)H(11)], [NMe(4)][] can be obtained. The (1)H{(11)B} DNMR study on in the temperature range from 298 to 203 K identified the weakly basic nitrogen atom in the pyridine ring as the proton accepting site in solid state and low temperature and revealed pronounced weakening of the nitrogen-proton interaction while the temperature increases. Capillary electrophoresis and X-ray diffraction confirmed the pyridine nitrogen atom as the proton binding site. Separation of the electrophoretically pure racemic [7-(2'-pyridyl)-7,8-nido-C(2)B(9)H(11)](-) ion into two peaks by the chiral selector beta-cyclodextrine has been achieved.

Contributions to the application of the transferability principle and the multipolar modeling of H atoms: electron-density study ofL-histidinium dihydrogen orthophosphate orthophosphoric acid. I

The electron density of L-histidinium dihydrogen orthophosphate orthophosphoric acid has been determined from X-ray and neutron diffraction data at low temperature (120 K). Topological analysis of the electron density has been used to analyse the effect of the multipolar refinement strategy on the electron-density model in the hydrogen-bonding regions. The electron density at low temperature has also been used to acquire high-quality experimental thermal parameters at room temperature using the transferability principle. Molecular vibrations, TLS and normal mode analysis are discussed and studied at both temperatures.