Material and energy intensity of fullerene production

Fullerenes are increasingly being used in medical, environmental, and electronic applications due to their unique structural and electronic properties. However, the energy and environmental impacts associated with their commercial-scale production have not yet been fully investigated. In this work, the life cycle embodied energy of C(60) and C(70) fullerenes has been quantified from cradle-to-gate, including the relative contributions from synthesis, separation, purification, and functionalization processes, representing a more comprehensive scope than used in previous fullerene life cycle studies. Comparison of two prevalent production methods (plasma and pyrolysis) has shown that pyrolysis of 1,4-tetrahydronaphthalene emerges as the method with the lowest embodied energy (12.7 GJ/kg of C(60)). In comparison, plasma methods require a large amount of electricity, resulting in a factor of 7-10× higher embodied energy in the fullerene product. In many practical applications, fullerenes are required at a purity >98% by weight, which necessitates multiple purification steps and increases embodied energy by at least a factor of 5, depending on the desired purity. For applications such as organic solar cells, the purified fullerenes need to be chemically modified to [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM), thus increasing the embodied energy to 64.7 GJ/kg C(60)-PCBM for the specified pyrolysis, purification, and functionalization conditions. Such synthesis and processing effects are even more significant for the embodied energy of larger fullerenes, such as C(70), which are produced in smaller quantities and are more difficult to purify. Overall, the inventory analysis shows that the embodied energy of all fullerenes are an order of magnitude higher than most bulk chemicals, and, therefore, traditional cutoff rules by weight during life cycle assessment of fullerene-based products should be avoided.     

Sympt?mes comportementaux et psychologiques de la démence: Liens entre la recherche psychosociale et les politiques.

Alzheimer's disease and other dementias represent a major health problem. Although memory loss is the most commonly known consequence of dementia, the majority of patients also present behavioral and psychological symptoms (BPSD). The contribution of psychosocial research includes the identification of patients' needs and the development of strategies for managing symptoms. This research field and health and education policies influence one another. All those concerned need to be informed and to work together in order to make knowledge about BPSD progress and to improve the care of patients suffering from dementia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Staging of ovine embryos and expression of the T-box genes Brachyury and Eomesodermin around gastrulation

The high rates of embryonic mortalities which follow in vitro production of ruminant embryos have emphasized the need for increased knowledge of early development. It is likely that early failures in embryonic development and placenta formation involve abnormal differentiation of mesoderm. The aim of this study was to investigate the pattern of expression of two T-box genes known to control the gastrulation process, Brachyury and Eomesodermin, by whole-mount in situ hybridization. To allow a more precise comparison of both expression patterns between embryos, we describe a new staging of pre-implanted ovine embryos by gross morphology and histology from pre-gastrulation stages to the beginning of neurulation. In pre-streak embryos primitive mesoderm cells delaminated in between the primitive endoderm and the epiblast. At that stage, no expression of Brachyury or Eomesodermin could be detected in the embryos. Early expression of both T-genes was observed by the early-streak stages in epiblast cells located close to the presumptive posterior pole of the embryos. Later on, during gastrulation both genes followed a pattern of expression similar to the ones described in other mammals. These observations suggest that other genes, which remain to be identified, are responsible for extra-embryonic mesoderm differentiation in ruminant embryos.     

Insertion of X-ray structures of proteins in membranes

Few structures of membrane proteins are known and their relationships with the membrane are unclear. In a previous report, 20 X-ray structures of transmembrane proteins were analyzed in silico for their orientation in a 36A-thick membrane [J. Mol. Graph. Model. 20 (2001) 235]. In this paper, we use the same approach to analyze how the insertion of the X-ray structures varies with the bilayer thickness. The protein structures are kept constant and, at each membrane thickness, the protein is allowed to tilt and rotate in order to accommodate at their best. The conditions are said to be optimal when the energy of insertion is minimal. The results show that most helix bundles require thicker membranes than porin barrels. Moreover, in a few instances, the ideal membrane thickness is unrealistic with respect to natural membranes supporting that the X-ray structure requires adaptation to stabilize in membrane. For instance, the squalene cyclase could adapt by bending the side chains of its ring of lysine and arginine in order to increase the hydrophobic surface in contact with membranes. We analyzed the distribution of amino acids in the water, interface and acyl chain layers of the membrane and compared with the literature.     

Structural and mechanical characterization of BCxNy thin films deposited by pulsed reactive magnetron sputtering

BC_xN_y thin films deposited at 250 °C by pulsed reactive magnetron sputtering of a B₄C target in an Ar/N₂ plasma were studied by elastic recoil detection analysis, Fourier transform infrared, Raman, and photoelectron spectroscopy, electron microscopy, and nanoindentation. In the concentration range of 6% to 100% N₂ in the sputter plasma the segregation into nanocrystalline hexagonal boron nitride and amorphous sp² carbon is the dominant process during the film growth. The stoichiometric ratio and structural details of the major phases depend on the N₂ concentration in the plasma and have significant influence on the Young′s modulus and the elastic recovery of the BC_xN_y thin films.     

Impact of Gram-negative bacteria in interaction with a complex microbial consortium on biogenic amine content and sensory characteristics of an uncooked pressed cheese

The impact of Gram-negative bacteria on sensory characteristics and production of volatile compounds as well as biogenic amines (BA) in the core of an uncooked pressed type model cheese was investigated in the presence of a defined complex microbial consortium. Eleven strains of Gram-negative bacteria, selected on the basis of their biodiversity and in vitro BA-production ability, were individually tested in a model cheese. Four out of 6 strains of Enterobacteriaceae (Citrobacter freundii UCMA 4217, Klebsiella oxytoca 927, Hafnia alvei B16 and Proteus vulgaris UCMA 3780) reached counts close to 6 log CFU g⁻¹ in the model cheese. In core of cheeses inoculated with Gram-negative bacteria, only slight differences were observed for microbial counts (Enterococcus faecalis or Lactobacillus plantarum count differences below 1 log CFU g⁻¹), acetate concentration (differences below 200 mg kg⁻¹) and texture (greater firmness) in comparison to control cheeses. Cheese core colour, odour and volatile compound composition were not modified. Although ornithine, the precursor of putrescine, was present in all cheeses, putrescine was only detected in cheeses inoculated with H. alvei B16 and never exceeded 2.18 mmol kg⁻¹ cheese dry matter. Cadaverine was only detected in cheeses inoculated with H. alvei B16, K. oxytoca 927, Halomonas venusta 4C1A or Morganella morganii 3A2A but at lower concentrations (<1.05 mmol kg⁻¹ cheese dry matter), although lysine was available. Only insignificant amounts of the detrimental BA histamine and tyramine, as well as isopentylamine, tryptamine or phenylethylamine, were produced in the cheese model by any of the Gram-negative strains, including those which produced these BA at high levels in vitro.     

Ecdysteroids from Chenopodium quinoa Willd., an ancient Andean crop of high nutritional value

Chenopodium quinoa Willd. (=quinoa) is a crop cultivated since ancient times by the Incas, which has a high nutritional value. Quinoa belongs to Chenopodiaceae, a family containing many ecdysteroid-containing species, including spinach.     

A versatile and colorful screening tool for the identification of arabinofuranose-acting enzymes

Selecting wall-nibblers: Three 4-nitrocatechol derivatives were designed to facilitate high-throughput screening of arabinofuranose hydrolases, enzymes that typically digest plant cell walls. The designed compounds can be used in solid and liquid media, and, importantly, one allows the specific detection of AXH-d, a specialized enzyme that only releases L-arabinose from disubstituted D-xylosyl moieties.