Nanocrystalline brookite with enhanced stability and photocatalytic activity: influence of lanthanum(III) doping.

Metastable TiO(2) polymorphs are more promising materials than rutile for specific applications such as photocatalysis or catalysis support. This was clearly demonstrated for the anatase phase but still under consideration for brookite, which is difficult to obtain as pure phase. Moreover, the surface doping of anatase with lanthanum ions is known to both increase the thermal stability of the metastable phase and improve its photocatalytic activity.

TEM image analysis and modelling: application to boehmite nanoparticles.

Boehmite occurs in the form of nanoparticles. Upon drying, it can form the alumina that is common in catalyst support used in refining and petrochemicals. The topotactic transformation of boehmite alumina led to an interest in the precise shape and size of these nanoparticles which is highly linked to the catalyst activity.

Use of polyols as particle size and shape controllers: application to boehmite synthesis from sol-gel routes.

Polyols were successfully used as size and shape controllers of oxide nanoparticles synthesized by soft chemistry in aqueous solution. The efficiency of acyclic polyols as a complexing agent depends obviously on the number of OH groups bonded to the carbon chain (and thus on the carbon chain length), but also on their stereochemistry. This innovating way to control morphology has been experienced for the synthesis of boehmite nanoparticles, whose morphology variations related to xylitol adsorption (C5 alditol) have been previously reported.

Restoration of foothills rough fescue grassland following pipeline disturbance in southwestern Alberta.

The effects of pipeline construction and reclamation techniques on the restoration of rough fescue plant communities following pipeline construction in southwestern Alberta, Canada were evaluated after 7-40 years. The pipeline construction right-of-way (ROW) sites varied from no recovery of rough fescue grassland to moderate recovery. The ROW sites had a higher proportion of introduced grasses and forbs, less topsoil, and poorer rangeland health than the adjacent undisturbed grassland.

Growth of boehmite particles in the presence of xylitol: morphology oriented by the nest effect of hydrogen bonding.

The ability to design nanoparticles size and shape through the addition of simple and commercially available organic molecules is of particular interest in the catalytic domain because huge amounts of very fine powders are needed. The origin of this effect is all the more difficult to elucidate because the involved interactions are weak. In this paper, we have investigated the shaping of boehmite AlO(OH) nanoparticles in the presence of polyols like xylitol (C(5) alditol) by a combined experimental and theoretical approach.

Intracerebral C6 glioma model in female hairless rats: assessment by using MRI and follow-up of irradiation.

An experimental intracerebral C6 glioma model in immunosuppressed female hairless rats has been developed. The rate of tumor uptake was evaluated by magnetic resonance imaging (MRI), using specific sequences without gadolinium enhancement. Twenty-four hours before intracerebral transplantation, a control cranial MRI was carried out and rats underwent a total body irradiation (TBI).

Human malignant glioma cell lines are sensitive to low radiation doses.

Malignant gliomas display aggressive local behavior and are not cured by existing therapy. Some cell lines that are considered radioresistant respond to low radiation doses (<1 Gy) with increased cell killing (low-dose hypersensitivity). In our study, 4 of 5 human glioma cell lines exhibited significant X-ray sensitivity at doses below 1 Gy.

Crystallographic, X-ray absorption, and IR studies of solid- and solution-state structures of tris(nitrato) N,N,N',N'-tetraethylmalonamide complexes of lanthanides. Comparison with the Americium complex.

To fine-tune the design of optimized donor ligands for nuclear waste actinide selective extraction, both electronic and molecular structures of the actinide complexes that are formed must be investigated. In particular, to achieve the selective complexation of transplutonium 3+ ions versus lanthanide 3+ ions is one of the major challenges, given the chemical similarities between these two f-element families. In this work, the structure of solvent-phase M(NO3)3(TEMA)2 complexes (Ln = Nd, Eu, Ho, Yb, Lu, Am; TEMA = N,N,N',N'-tetraethylmalonamide) was investigated by liquid-phase spectroscopic methods among which extended X-ray absorption fine structure played a major role.

Characterization of an Al-, Ga-based catalyst by Ga NMR and XAS.

Both Nuclear Magnetic Resonance (NMR) and X-Ray absorption spectroscopies characterize local order around the observed nuclei. With the recent progresses of 71Ga solid state NMR, it has become possible to take advantage of the complementary information that can be obtained using these two methods. This opens the possibility of a more thorough description of the first coordination shells of Ga in oxide.

Development of an intracerebral glioma model in whole body irradiated hairless rats.

Aims: To study the in vivo radiosensitivity of malignant gliomas, an animal glioma model was developed using the implantation of glioma cell lines into the brain of the Hairless rat (a mutant from the Sprague-Dawley strain, characterised by its complete absence of hair).

Methods: 10(6) malignant cells were suspended in 10 microliters phosphate buffered saline (PBS) and injected at a 4 microns depth into the left frontal lobe of an anaesthetised animal through a small craniotomy hole without opening the dura mater. The glioma cell line C6 (obtained from a chemically-induced rat glioblastoma) was introduced into 11 animals, and the human glioblastoma line G5 into 12 animals.