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101.
Sigbjrn Grini Kostiantyn V. Sopiha Nils Ross Xin Liu Tor S. Bjrheim Charlotte Platzer‐Bjrkman Clas Persson Lasse Vines 《Liver Transplantation》2019,9(27)
Sodium and oxygen are prevalent impurities in kesterite solar cells. Both elements are known to strongly impact performance of the kesterite devices and can be connected to efficiency improvements seen after heat treatments. The sodium distribution in the kesterite absorber is commonly reported, whereas the oxygen distribution has received less attention. Here, a direct relationship between sodium and oxygen in kesterite absorbers is established using secondary ion mass spectrometry and explained by defect analyses within the density functional theory. The calculations reveal a binding energy of 0.76 eV between the substitutional defects NaCu and OS in the nearest neighbor configuration, indicating an abundance of Na? O complexes in kesterite absorbers at relevant temperatures. Oxygen incorporation is studied by introducing isotopic 18O at different stages of the Cu2ZnSnS4/Mo/soda‐lime glass baseline processing. It is observed that oxygen from the Mo back contact and contaminations during the sulfurization are primary contributors to the oxygen distribution. Indeed, unintentional oxygen incorporation leads to immobilization of sodium. This results in a strong correlation between sodium and oxygen, in excellent agreement with the theoretical calculations. Consequently, oxygen availability should be monitored to optimize postdeposition heat treatments to control impurities in kesterite absorbers and ultimately, the solar cell efficiency. 相似文献
102.
Maga Daniel Thonemann Nils Hiebel Markus Sebastião Diogo Lopes Tiago F. Fonseca César Gírio Francisco 《The International Journal of Life Cycle Assessment》2019,24(2):266-280
The International Journal of Life Cycle Assessment - The use of bagasse and trash from sugarcane fields in ethanol production is supposed to increase the ethanol yield per hectare, to reduce the... 相似文献
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The self-cleaving hepatitis delta virus (HDV) ribozyme is essential for the replication of HDV, a liver disease causing pathogen in humans. The catalytically critical nucleotide C75 of the ribozyme is buttressed by a trefoil turn pivoting around an extruded G76. In all available crystal structures, the conformation of G76 is restricted by stacking with G76 of a neighboring molecule. To test whether this crystal contact introduces a structural perturbation into the catalytic core, we have analyzed approximately 200 ns of molecular dynamics (MD) simulations. In the absence of crystal packing, the simulated G76 fluctuates between several conformations, including one wherein G76 establishes a perpendicular base quadruplet in the major groove of the adjacent P1 stem. Second-site mutagenesis experiments suggest that the identity of the nucleotide in position 76 (N76) indeed contributes to the catalytic activity of a trans-acting HDV ribozyme through its capacity for hydrogen bonding with P1. By contrast, in the cis-cleaving genomic ribozyme the functional relevance of N76 is less pronounced and not correlated with the P1 sequence. Terbium(III) footprinting and additional MD show that the activity differences between N76 mutants of this ribozyme are related instead to changes in average conformation and modified cross-correlations in the trefoil turn. 相似文献
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Focus on function: single molecule RNA enzymology 总被引:2,自引:0,他引:2
The ability of RNA to catalyze chemical reactions was first demonstrated 25 years ago with the discovery that group I introns and RNase P function as RNA enzymes (ribozymes). Several additional ribozymes were subsequently identified, most notably the ribosome, followed by intense mechanistic studies. More recently, the introduction of single molecule tools has dissected the kinetic steps of several ribozymes in unprecedented detail and has revealed surprising heterogeneity not evident from ensemble approaches. Still, many fundamental questions of how RNA enzymes work at the molecular level remain unanswered. This review surveys the current status of our understanding of RNA catalysis at the single molecule level and discusses the existing challenges and opportunities in developing suitable assays. 相似文献
108.
Link N Brunner TJ Dreesen IA Stark WJ Fussenegger M 《Biotechnology and bioengineering》2007,98(5):1083-1093
Owing to their small size, synthetic nanoparticles show unprecedented biophysical and biochemical properties which may foster novel advances in life-science research. Using flame-spray synthesis technology we have produced non-coated aluminum-, calcium-, cerium-, and zirconium-derived inorganic metal oxide nanoparticles which not only exhibit high affinity for nucleic acids, but can sequester such compounds from aqueous solution. This non-covalent DNA-binding capacity was successfully used to transiently transfect a variety of mammalian cells including human, reaching transfection efficiencies which compared favorably with classic calcium phosphate precipitation (CaP) procedures and lipofection. In this straightforward protocol, transfection was enabled by simply mixing nanoparticles with DNA in solution prior to addition to the target cell population. Transiently transfected cells showed higher production levels of the human secreted glycoprotein SEAP compared to isogenic populations transfected with established technologies. Inorganic metal oxide nanoparticles also showed a high binding capacity to human-pathogenic viruses including adenovirus, adeno-associated virus and human immunodeficiency virus type 1 and were able to clear these pathogens from aqueous solutions. The DNA transfection and viral clearance capacities of inorganic metal oxide nanoparticles may provide cost-effective biopharmaceutical manufacturing and water treatment in developing countries. 相似文献
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Nils Hennion Mickael Durand Ccile Vriet Joan Doidy Laurence Maurousset Rmi Lemoine Nathalie Pourtau 《Physiologia plantarum》2019,165(1):44-57
In plants, the root is a typical sink organ that relies exclusively on the import of sugar from the aerial parts. Sucrose is delivered by the phloem to the most distant root tips and, en route to the tip, is used by the different root tissues for metabolism and storage. Besides, a certain portion of this carbon is exuded in the rhizosphere, supplied to beneficial microorganisms and diverted by parasitic microbes. The transport of sugars toward these numerous sinks either occurs symplastically through cell connections (plasmodesmata) or is apoplastically mediated through membrane transporters (MST, mononsaccharide tranporters, SUT/SUC, H+/sucrose transporters and SWEET, Sugar will eventually be exported transporters) that control monosaccharide and sucrose fluxes. Here, we review recent progresses on carbon partitioning within and outside roots, discussing membrane transporters involved in plant responses to biotic and abiotic factors. 相似文献
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