Evaluation of the morphological changes in the lungs of BALB/c mice after inhalation of spherical and rod-shaped titanium nanoparticles

Titanium nanoparticles are widely used by industry in consumer products such as sunscreens and some cosmetic products due to their specifically engineered properties. Some of these properties may, however, increase the toxicity of the nanoparticles which in turn may affect human and environmental health. Therefore, it is of utmost importance to study the possible effects of these particles through in vivo studies, which might produce different results than in vitro cell studies. The current study aimed to investigate the possible remodelling in the lungs of BALB/c mice by means of light and transmission electron microscopy after inhalation of spherical and rod-shaped titanium nanoparticles at two different concentrations. The focus of this paper was to demonstrate whether whole body exposure to different concentrations of the said nanoparticles could induce an inflammatory response in the lungs and no inter particle comparison was done or retention investigated. Animals were divided into five experimental groups: control, high and low concentration groups exposed to the spherical-shaped particles, as well as high and low concentration groups exposed to the rod-shaped particles. Histological and ultrastructural changes, typical of an inflammatory response, were noted in the lungs of the exposed animals. These changes were not observed in the lungs of the control animals. It can be concluded from this study that titanium nanoparticles may cause inflammatory reactions in the lungs of animals exposed through inhalation, as indicated by the presence of inflammatory cells and congestion of inter-alveolar areas. This has implications for individuals who may be potentially exposed during the production and use of titanium nanoparticles.     

The importance of peri-interactions in determining the half-chair conformation of the dihydropyran ring in 2-benzopyrans. Stereochemical consequences

peri-Interactions are important in determining both the conformation of the dihydropyran ring of 2-benzopyrans as well as the stereochemistry of its substituents.     

Determination of slopes of calibration lines in multi element XRF analysis of thin films using polychromatic excitation from Mo,Au, W,and Cr anodes and one standard

An algorithm is described for the theoretical calculation of the slopes of calibration lines for the elements of the K-series in multi element X-ray fluorescence analysis of thin films using polychromatic excitation with X-ray tubes producing widely differing primary radiation intensity profiles. The mathematical equations used to calculate slopes as a function of atomic number are based on the fundamental relationship between fluorescent intensity and atomic number, fluorescent yield, concentration and mass absorption coefficients of the analyte for primary radiation. A normalisation procedure based on a single known slope in the series ensured that the calculated slopes were correct for the particular measuring conditions.     

The preparation and some reactions of chloro(η4-cycloocta-1,5-diene)(η5-cyclopentadienyl)ruthenium(II): A versatile,new synthetic precursor for cyclopentadienylruthenium(II) chemistry

Facile substitution of the cyclooctadiene and/or chloro ligands in [(η⁵-C₅H₅)Ru(C₈H₁₂Cl] (C₈H₁₂ = cycloocta-1,5-diene) under mild reaction conditions provides high yield synthetic routes to a range of new neutral and cationic cyclopentadienylruthenium(II) complexes.     

Cationic ruthenium and osmium systems: V. Cationic osmium(II) hydrazine and hydrazone complexes derived from the polymer [OsCl2(COD)]x (COD = cyclo-octa-1,5-diene; x > 2). The crystal structure of [Os(COD(CNBut)2(NH2H:CMe2)2][BPh4]2·(acetone)2

The polymer [OsCl₂(COD)]_x (1; COD = cycloocta-1,5-diene; x > 2) and the appropriate hydrazine have been used to prepare the salts [OsCl(COD)(N₂H₄)₃]BPh₄ (2), [Os(COD)(N₂H₄)₄][BPh₄]₂ (3) and [OsCl(COD)(NH₂NMe₂)₃]PF₆ (4). Treatment of 3 with t-butyl isocyanide produced mer-[Os(CNBu^t)₃(N₂H₄)₃][BPh₄]₂ (5) and trans-[Os(CNBu^t)₄(N₂H₄)₂][BPh₄]₂ (6) from refluxing ethanol and the hydrazone complex [Os(COD)(CNBu^t)₂(NH₂N:CMe₂)₂][BPh₄]₂ (7) from refluxing acetone. Reactions of 3 and L {L = CNxylyl, P(OMe)₃, and P(OMe)₃Ph; xylyl = 2,6-dimethylphenyl} in acetone gave trans-[Os(NH₂N:CMe₂)₂L₄][BPh₄]₂ (8). The crystal structure of [Os(COD)(CNBu^t)₂(NH₂N:CMe₂)₂][BPh₄]₂·(Acetone)₂ (7) has been determined from three-dimensional X-ray counter data and refined to a final R (on F) of 0.090 based on 3014 reflections. The compound crystallizes in the monoclinic space group C2/c with four formula units in a cell of dimensions a 24.60(2), b 13.31(1), c 24.12(2) Å and β 111.51(2)°. The cation has a crystallographically imposed C₂ symmetry, with octahedral coordination of the osmium atom, assuming that the COD ligand occupies two adjacent coordination sites. Coordination of the mutually trans hydrazone ligands to the osmium atom is through the amino-N atoms rather than through the less basic, more sterically hindered, imino-N atoms. relevant bond distances are: Os-N 2.19(2) (mean), Os-C(COD) 2.19(2) and 2.29(2), and Os-C(isocyanide) 1.93(2) (mean) Å.     

Heteroatom‐containing ferrocene derivatives as catalysts for MWCNTs and other shaped carbon nanomaterials

The effects of heteroatom‐containing ferrocene catalysts on the materials produced from chemical vapour deposition (CVD) floating catalyst synthesis were investigated. Specifically, the influence of nitrogen‐ and oxygen‐containing ferrocenoyl imidazolide and (N‐phenylcarbamoyl)ferrocene, and sulfur‐ and oxygen‐containing S,S‐bis(ferrocenylmethyl)dithiocarbonate on the structural morphology and distribution of the products as well as properties such as the thermal stability and crystallinity were studied. In addition, the influence of reaction parameters such as catalyst concentration and temperature were also investigated. The nitrogen‐containing catalysts produced N‐doped multi‐walled carbon nanotubes (N‐MWCNTs), whereas the sulfur‐containing catalyst produced primarily nano‐ and microspheres. A concentration of 2.5 wt% ferrocenoyl imidazolide was shown to be optimal for the synthesis of MWCNTs at 850 °C, with very low metal iron residue, highest thermal stability and highest yield (95%). In general, bamboo compartment length for N‐doped MWCNTs increased with temperature. Crystallinity trends were shown to be independent of catalyst and catalyst concentration in all cases and only dependent on temperature. The average diameter for MWCNTs was shown to be dependent on temperature, choice of catalyst and catalyst concentration in all cases. Copyright © 2012 John Wiley & Sons, Ltd.     

Reaction of Aluminium Chloride with Benzo[C]- and Naphtho[2,3-C]pyrans

Aluminium(III) chloride is shown to cause (reversible) cis-trans stereoisomerisations in some benzo[c]- and naphtho[2,3-c]pyrans at ambient temperature.     

A High Yielding Synthesis of Racemic Hongconin

Racemic hongconin 1 has been synthesized from adduct 2 formed by reaction between 1-methoxycyclohexa-1,4-diene and benzoquinone. The synthetic strategy includes Fries and Claisen rearrangements, base and cerium(IV) initiated pyran ring formation, C-4 pyran ring hydroxylation and silver(II) mediated oxidation.     

A numerical and experimental study of natural convective heat transfer from an inclined isothermal square cylinder with an exposed top surface

Natural convective heat transfer from an isothermal inclined cylinder with a square cross-section which have an exposed top surface and is, in general, inclined at an angle to the vertical has been numerically and experimentally studied. The cylinder is mounted on a flat adiabatic base plate, the cylinder being normal to the base plate. The numerical solution has been obtained by solving the dimensionless governing equations subject to the boundary conditions using the commercial cfd solver, FLUENT. The flow has been assumed to be symmetrical about the vertical center-plane through the cylinder. Results have only been obtained for Prandtl number of 0.7. Values of inclination angle between 0° and 180° and a wide range of Rayleigh number and the dimensionless cylinder width, W = w/h, have been considered. The effects of Dimensionless widths, Rayleigh numbers, and inclination angles on the mean Nusselt number for the entire cylinder and for the mean Nusselt numbers for the various surfaces that make up the cylinder have been examined. Empirical equations for the heat transfer rates from the entire cylinder have been derived.