Aerosol characterization and lung deposition of synthesized TiO2 nanoparticles for murine inhalation studies

This study presents a novel exposure protocol for synthesized nanoparticles (NPs). NPs were synthesized in gas phase by thermal decomposition of metal alkoxide vapors in a laminar flow reactor. The exposure protocol was used to estimate the deposition fraction of titanium dioxide (TiO₂) NPs to mice lung. The experiments were conducted at aerosol mass concentrations of 0.8, 7.2, 10.0, and 28.5 mg m^?3. The means of aerosol geometric mobility diameter and aerodynamic diameter were 80 and 124 nm, and the geometric standard deviations were 1.8 and 1.7, respectively. The effective density of the particles was approximately from 1.5 to 1.7 g cm^?3. Particle concentration varied from 4 × 10⁵ cm^?3 at mass concentrations of 0.8 mg m^?3 to 12 × 10⁶ cm^?3 at 28.5 mg m^?3. Particle phase structures were 74% of anatase and 26% of brookite with respective crystallite sized of 41 and 6 nm. The brookite crystallites were approximately 100 times the size of the anatase crystallites. The TiO₂ particles were porous and highly agglomerated, with a mean primary particle size of 21 nm. The specific surface area of TiO₂ powder was 61 m² g^?1. We defined mice respiratory minute volume (RMV) value during exposure to TiO₂ aerosol. Both TiO₂ particulate matter and gaseous by-products affected respiratory parameters. The RMV values were used to quantify the deposition fraction of TiO₂ matter by using two different methods. According to individual samples, the deposition fraction was 8% on an average, and when defined from aerosol mass concentration series, it was 7%. These results show that the exposure protocol can be used to study toxicological effects of synthesized NPs.     

Organic‐Inorganic Hybrid Materials: Syntheses,X‐ray Diffraction Study,and Characterisations of Manganese,Cobalt, and Copper Complexes of Modified Bis(phosphonates)

Four new cobalt, manganese, and copper bis(phosphonates), [Co₂{Cl₂C(PO₃)₂}(H₂O)₇ · 4H₂O] ( 1 ), [Co{Cl₂C(PO₂O(C(O)C₆H₅))₂(H₂O)₅} · 2H₂O{Cl₂C(PO₂O(C(O)C₆H₅))₂}{Co(H₂O)₆}] ( 2 ), [Mn{[Cl₂C(PO₂O(C(O)C₆H₅))₂](H₂O)₃}] ( 3 ), and [Cu{(CH₂C₅H₅N)C(OH)(PO₃H)₂}₂ · 4H₂O] ( 4 ), were prepared by gel, liquid, and evaporation crystallisation methods. Compounds 1 – 4 were characterised by X‐ray single‐crystal diffraction, elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The effects of metal and various substituted groups in bis(phosphonate) ligands on the structure formation of bis(phosphonates) were studied. In the structure of 1 , the clodronic acid ligand ( L1 ) is in bischelating bonding mode, and the dinuclear units of 1 are surrounded by two‐dimensional water cluster patterns. The hydrogen bond network of compound 1 is extended to a three‐dimensional framework when the phosphonate oxygen atoms serve as hydrogen‐bond acceptors. In complex 2 , the CoO₆ octahedron shares a corner of one PCO₃ tetrahedron of the dibenzoyl derivative of clodronic acid ligand ( L2 ), and forms a two‐dimensional hydrogen bonding network, which consists of [Co(H₂O)₆}]²⁺ cations, lattice water molecules and L2 ligand molecules. Compound 3 , in turn, consists of dimeric building blocks built up of PCO₃ tetrahedra of the ligand L2 , which connect the corner‐sharing MnO₆ octahedra and form an overall 2D structure through hydrogen bonds of coordinated and crystal water molecules and phosphonate oxygen atoms. Complex 4 is among the first metal complexes of risedronic acid ( L3 ). In compound 4 , two L3 ligand molecules chelate tridentately the Cu^II atom at the center of symmetry, and the monomeric units of 4 are connected to a 3D structure through hydrogen bonding of coordinated and lattice water molecules to both protonated and deprotonated phosphonate oxygen atoms and protonated nitrogen atoms in the pyridine ring.     

Complex formation between a tetramesityl sulfonated resorcarene and alkylammonium ions: a mass spectrometric study of noncovalent interactions

Noncovalent complex formation between a tetramesityl sulfonated tetramethyl resorcarene and primary, secondary, and tertiary alkylammonium ions was investigated by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Competition measurements, collision-induced dissociation, and gas-phase hydrogen/deuterium (H/D)-exchange reactions were employed to elucidate the interactions involved in complexation, the stability of the complexes, and the position of the guest with relation to the resorcarene. The complex formation ability of tetramesityl sulfonated resorcarene and the stability of the compexes were compared with the corresponding properties of tetratosylium tetraethyl resorcarene, which has been studied previously. Complex formation and the properties of the complexes were most strongly determined by the steric properties of the guests and their ability to form hydrogen bonds. Comparison of the two host molecules revealed the impact of steric hindrance in tetramesityl sulfonated tetramethyl resorcarene.     

N-oxides of the quinoxaline series

When di-N-oxides of -hydroxymethyl derivatives of quinoxaline are heated with dimethyl sulfoxide, the oxidation of a CH₂OH group and the reduction of a neighboring NO group takes place. The N-oxides of 2,3-bis(hydroxymethyl)qninoxaline undergo similar redox processes in the presence of alkaline reagents.For part XV, see [5].     

Pyrazines and their N-oxides

The N-oxides of 2- and 2,3-substituted pyrazines were synthesized. It was found that the synthesized 2-formylpyrazine N,N-dioxide, in which the aldehyde group is in the hydrated form, undergoes redox transformations leading to deoxidation of one of the ring nitrogens and oxidation of the dihydroxymethyl group to a carboxyl group under the influence of alkaline reagents.See [10] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1275–1280, September, 1972.     

A regression technique to analyze the second-order nonlinear optical response of thin films

We present a new technique, based on regression analysis, to determine the second-order nonlinear optical susceptibility tensor of thin films. The technique does not require the absolute levels or phases of measured signals to be mutually calibrated. In addition it yields indicators that address the quality of theoretical models describing the sample. We use the technique to determine the susceptibility tensor of samples of a nonracemic chiral material which have very low symmetry (both chiral and anisotropic) and have many independent tensor components. The results show the importance of using detailed theoretical models that account for the linear optical properties of the sample.     

ESI-FTICR investigation of triethylammonium ion-driven resorcin[4]arene dimer formation and structure

In the course of mass spectrometric measurements a self-assembled hydrogen bonded resorcinarene dimer was observed, the formation of which was driven by the binding of triethylammonium ion as a guest and as an ionic label.