Blockade of 5-HT2A receptors suppresses hyperthermic but not cardiovascular responses to psychosocial stress in rats

The aim of this study was to determine whether 5-HT2A receptors mediate cardiovascular and thermogenic responses to acute psychological stresses. For this purpose, adult male Wistar hooded rats instrumented for telemetric recordings of either electrocardiogram (ECG) (n=12) or arterial pressure (n=12) were subjected, on different days, to four 15-min episodes of social defeat. Prior to stress, animals received s.c. injection of the selective 5-HT2A receptor antagonist SR-46349B (trans-4-((3Z)3-[(2-dimethylaminoethyl)oxyimino]-3-(2-fluorophenyl)propen-1-yl)-phenol, hemifumarate) (at doses of 0.3, 1.0 and 3.0 mg/kg) or vehicle. The drug had no effect on basal heart rate or heart rate variability indexes, arterial pressure, and core body temperature. Social defeat elicited significant and substantial tachycardic (347±7 to 500±7 bpm), pressor (77±4 to 97±4 mm Hg) and hyperthermic (37.0±0.3 to 38.5±0.1 °C) responses. Blockade of 5-HT2A receptors, at all doses of the antagonist, completely prevented stress-induced hyperthermia. In contrast, stress-induced cardiovascular responses were not affected by the blockade (except small reduction of tachycardia by the highest dose of the drug). We conclude that in rats, 5-HT2A receptors mediate stress-induced hyperthermic responses, but are not involved in the genesis of stress-induced rises in heart rate or arterial pressure, and do not participate in cardiovascular control at rest.

Preparation of hemicyanine dye encapsulated silica particles and their application in cotton fabrics

Trans-4- [p- (N, N-Die (2-hydroxyethyl)) styryl] -N- ethyl pyridinium bromide (DHEASPBr-C2), a hemicyanine fluorescent dye, was encapsulated into silica nanoparticles by co-hydrolysis and co-condensation of organosilanes in the presence of the dye. The dye containing silica nanoparticles were applied onto cotton fabrics. Scanning electron microscopy (SEM), UV–vis spectra, single-photon emission fluorescence spectra and reflectance spectra of the samples were characterized. The SEM results showed that the particle size (ranging from 100-200 nm) and dye encapsulating (1.5-8.1 mg dye per g silica matrix) could be adjusted by the concentration of fluorescent dye and organosilanes. The reflectance of the treated cotton fabrics showed that there were obvious adsorption spectra in 410 - 540 nm and emission spectra in 560 - 700 nm.

Recommendations for a trans-European dietary assessment method in children between 4 and 14 years

Background/Objectives: The main objective of European Food Consumption Validation (EFCOVAL)-child Project is to define and evaluate a trans-European methodology for undertaking national representative dietary surveys among children in the age group of 4–14 years. In the process of identifying the best dietary assessment methodologies, experts were brought together at a workshop. The paper presents the discussion of the best available method and the final recommendations for a trans-European dietary assessment method among 4- to 14-year-old children.
Subjects/Methods: The starting point was to investigate whether the method (two non-consecutive 24-h dietary recalls (24-HDRs)) suggested for the adults in European Food Consumption Survey Method (EFCOSUM) would be usable for children in
the age group between 4 and 14 years. However, all available dietary assessment methods were included in the discussion to ensure that the final recommendation would be based on the best evidence. Six criteria were defined and used as additional
guidance in the process.
Results: The literature does not give a clear recommendation on the dietary assessment methods that are most suitable for children in the age group of 4–14 years. Nevertheless, on the basis of the literature, the recommendations were separated for preschoolers (4–6 years) and schoolchildren (7–14 years).
Conclusion: For preschoolers, two non-consecutive days of a structured food record are recommended, using a (for children adapted) picture booklet and household measures for portion-size estimation. For schoolchildren, repeated 24-HDRs are recommended, using a picture booklet and household measures for portion-size estimation. In addition, the child should bring a booklet to register what is eaten out of home. One parent should assist the schoolchild at the 24-HDR interview, and therefore face-to-face interviews are required.

catena-Poly[[[bis[(-)-O-bornyldithiocarbonato-κ2S,S']nickel(II)]-μ-4,4'-bipyridine-κ2N:N'] chloroform disolvate]

The Ni atom in the linear polymeric title complex, {[Ni(C₁₁H₁₇OS₂)₂(C₁₀H₈N₂)]·2CHC1₃}_n or {Ni[S₂C(-)-OC₁₀H₁₇)]₂(NC₅H₄C₅H₄N)·2CHC1₃}_n, is octahedrally coordinated within a trans-N₂S₄ donor set. There are two crystallographically independent polymers and two independent CHC1₃ molecules in the structure. For each polymer unit, the Ni atom and the axis of the 4,4'-bipyridine ligand are located on a twofold axis.

Self-assembly and film stability of a micelle of a single-chain quaternary ammonium amphiphile containing azobenzene on mica

The self-assembling behavior of a single-chain quaternary ammonium amphiphile bearing azobenzene (C₁₂AzoC₆N⁺) on freshly cleaved mica sheet has been investigated by atomic force microscopy (AFM) method. Confocal microscopic Raman spectra confirm the adsorption of the self-assembled monolayer structure. Ex-situ AFM reveals that C₁₂AzoC₆N⁺ forms branch-like stripes indicating the fusion and reorganization of the micelles during drying in air as the in-situ AFM has revealed that surfactant forms spherical micelles on the mica surface. The nano-sized surface structure is strongly dependent on the change of molecular structure, which resulted from photo-induced isomerization. The nano-sized stripe is quite stable even being annealed at 90 °C for 4 h.

Azobenzene moiety variation directing self-assembly and photoresponsive behavior of azo-surfactants

The effect of varying the position of the azobenzene group within two comparable photoresponsive amphiphiles on their capability to form lyotropic liquid crystals (LLCs) was investigated in detail in this study. Two photoresponsive amphiphiles having comparable structures were designed and synthesized consisting of hydrophilic oligooxyethylene units, a hydrophobic alkyl chain and a light-sensitive azobenzene moiety. When the azobenzene group was located in the middle of the hydrophobic alkyl chain, multiple LLC phases were observed at various water contents in the azo-surfactant–water binary system. In contrast, when the azobenzene group was directly attached to the hydrophilic domain, the azo-surfactant–water binary system exhibited only lamellar phases. The temperature dependence of these self-organised nanostructures was also investigated by the combination of small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and rheology. Under alternating UV and visible light irradiation, reversible trans–cis photoisomerization of the azobenzene group occurred efficiently in dilute solution for both azo-surfactants. However, only photoisomerization of the surfactant possessing the azobenzene group localized in the middle of the alkyl chain induced significant changes in the self-assembled structure and its bulk properties. This study demonstrates that self-assembly and photoresponsive behaviour of photosensitive amphiphiles is extremely sensitive to the position of the photoactive moiety within the surfactant molecular architecture.

Conditions favoring the formation of monomeric Pt(III) derivatives in the electrochemical oxidation of trans-[Pt(II){(p-BrC6F4)NCH2CH2NEt2}Cl(py)]

Characterization of the anticancer active compound trans-[Pt^II{(p-BrC6F4)NCH2CH2NEt2}Cl(py)] is described along with identification of electrochemical conditions that favor formation of a monomeric one-electron-oxidized Pt^III derivative. The square-planar organoamidoplatinum(II) compound was synthesized through a carbon dioxide elimination reaction. Structural characterization by using single-crystal X-Ray diffraction reveals a trans configuration with respect to donor atoms of like charges. As Pt^III intermediates have been implicated in the reactions of platinum anticancer agents, electrochemical conditions favoring the formation of one-electron-oxidized species were sought. Transient cyclic voltammetry at fast scan rates or steady-state rotating disc and microelectrode techniques in a range of molecular solvents and an ionic liquid confirm the existence of a well-defined, chemically and electrochemically reversible one-electron oxidation process that, under suitable conditions, generates a Pt^III complex, which is proposed to be monomeric [Pt^III{(p-BrC6F4)NCH2CH2NEt2}Cl(py)]⁺. Electron paramagnetic resonance spectra obtained from highly non-coordinating dichloromethane/([Bu4N][B(C6F5)4]) solutions, frozen to liquid nitrogen temperature immediately after bulk electrolysis in a glove box, support the Pt^III assignment rather than formation of a Pt^II cation radical. However, the voltammetric behavior is highly dependent on the timescale of the experiments, temperature, concentration of trans-[Pt^II{(p-BrC6F4)NCH2CH2NEt2}- Cl(py)], and the solvent/electrolyte. In the low-polarity solvent CH2Cl2 containing the very weakly coordinating electrolyte [Bu4N][B(C6F5)4], a well-defined reversible one-electron oxidation process is observed on relatively long timescales, which is consistent with the stabilization of the cationic platinum(III) complex in non-coordinating media. Bulk electrolysis of low concentrations of [Pt{(p-BrC6F4)NCH2CH2NEt2}Cl(py)] favors the formation of monomeric [Pt^III{(p-BrC6F4)NCH2CH2NEt2}Cl(py)]⁺. Simulations allow the reversible potential of the Pt^II/Pt^III process and the diffusion coefficient of [Pt^III{(p-BrC6F4)- NCH2CH2NEt2}Cl(py)]⁺ to be calculated. Reversible electrochemical behavior, giving rise to monomeric platinum(III) derivatives, is rare in the field of platinum chemistry.

Optical actuation of inorganic/organic interfaces: comparing peptide-azobenzene ligand reconfiguration on gold and silver nanoparticles

Photoresponsive molecules that incorporate peptides capable of material-specific recognition provide a basis for biomolecule-mediated control of the nucleation, growth, organization, and activation of hybrid inorganic/organic nanostructures. These hybrid molecules interact with the inorganic surface through multiple noncovalent interactions which allow reconfiguration in response to optical stimuli. Here, we quantify the binding of azobenzene-peptide conjugates that exhibit optically triggered cis-trans isomerization on Ag surfaces and compare to their behavior on Au. These results demonstrate differences in binding and switching behavior between the Au and Ag surfaces. These molecules can also produce and stabilize Au and Ag nanoparticles in aqueous media where the biointerface can be reproducibly and reversibly switched by optically triggered azobenzene isomerization. Comparisons of switching rates and reversibility on the nanoparticles reveal differences that depend upon whether the azobenzene is attached at the peptide N- or C-terminus, its isomerization state, and the nanoparticle composition. Our integrated experimental and computational investigation shows that the number of ligand anchor sites strongly influences the nanoparticle size. As predicted by our molecular simulations, weaker contact between the hybrid biomolecules and the Ag surface, with fewer anchor residues compared with Au, gives rise to differences in switching kinetics on Ag versus Au. Our findings provide a pathway toward achieving new remotely actuatable nanomaterials for multiple applications from a single system, which remains difficult to achieve using conventional approaches.

Optical actuation of inorganic/organic interfaces: comparing peptide-azobenzene ligand reconfiguration on gold and silver nanoparticles

Photoresponsive molecules that incorporate peptides capable of material-specific recognition provide a basis for biomolecule-mediated control of the nucleation, growth, organization, and activation of hybrid inorganic/organic nanostructures. These hybrid molecules interact with the inorganic surface through multiple noncovalent interactions which allow reconfiguration in response to optical stimuli. Here, we quantify the binding of azobenzene-peptide conjugates that exhibit optically triggered cis-trans isomerization on Ag surfaces and compare to their behavior on Au. These results demonstrate differences in binding and switching behavior between the Au and Ag surfaces. These molecules can also produce and stabilize Au and Ag nanoparticles in aqueous media where the biointerface can be reproducibly and reversibly switched by optically triggered azobenzene isomerization. Comparisons of switching rates and reversibility on the nanoparticles reveal differences that depend upon whether the azobenzene is attached at the peptide N- or C-terminus, its isomerization state, and the nanoparticle composition. Our integrated experimental and computational investigation shows that the number of ligand anchor sites strongly influences the nanoparticle size. As predicted by our molecular simulations, weaker contact between the hybrid biomolecules and the Ag surface, with fewer anchor residues compared with Au, gives rise to differences in switching kinetics on Ag versus Au. Our findings provide a pathway toward achieving new remotely actuatable nanomaterials for multiple applications from a single system, which remains difficult to achieve using conventional approaches.

The impact of trans fat regulation on social inequalities in coronary heart disease in Australia

To The Editor: The evidence that industrially produced trans fatty acids (TFAs) increase the risk of coronary heart disease is compelling, and it is widely agreed that their use in food products should be minimised.1-3 Dietary TFAs are generally found in higher quantities in “unhealthy” food products,4 consumption of which is also found to follow predictable sociodemographic patterns.5 Thus, although the average TFA intake for Australians is relatively low, socioeconomically disadvantaged people are likely to disproportionately represent those with above average intakes.