10 research outputs found
Design rules for high mobility xanthene-based hole transport materials
Tunable and highly conductive hole transport materials are crucial for the performance of organic electronics applications such as organic light emitting diodes and perovskite solar cells. For commercial applications, these materials\u27 requirements include easy synthesis, high hole mobility, and highly tuned and compatible electronic energy levels. Here, we present a systematic study of a recently discovered, easy-to-synthesize class of spiro[fluorene-9,9′-xanthene]-based organic hole transport materials. Systematic side group functionalization allows us to control the HOMO energy and charge carrier mobility. Analysis of the bulk simulations enables us to derive design rules for mobility enhancement. We show that larger functional groups (e.g. methyl) decrease the conformational disorder due to steric effects and thus increase the hole mobility. Highly asymmetric or polar side groups (e.g. fluorine), however, increase the electrostatic disorder and thus reduce the hole mobility. These generally applicable design rules will help in the future to further optimize organic hole transport materials
Further studies of green petal and other leafhopper-transmitted viruses infecting strawberry and clover
Enige proeven en beschouwingen over de identificatie van heksenbezemvirussen, in het bijzonder van klavers, in Nederland en Italië
Mycoplasma and allied diseases of forest trees in India and vector-host-pathogen interactions
The Family Acholeplasmataceae (Including Phytoplasmas)The Prokaryotes
The family Acholeplasmataceae was originally established to
accommodate the genus Acholeplasma, comprising the mollicutes that
could be cultivated without the supplement of cholesterol and that
use UGA as a stop codon instead of coding for tryptophan. It was
later shown that the phytoplasmas, a large group of uncultivable,
wall-less, non-helical mollicutes that are associated with plants and
insects, shared taxonomically relevant properties with members of the
genus Acholeplasma. Being not cultivable in vitro in axenic culture, the
phytoplasmas could not be classified using the standards used for other
mollicutes and are named using the category of Candidatus, as “Ca.
Phytoplasma.”
Although phytoplasmas are associated with habitats and ecology
different from acholeplasmas, the two genera Acholeplasma and
“Candidatus Phytoplasma” are phylogenetically related and form a
distinct clade within the Mollicutes. The persisting inability to grow
the phytoplasmas in vitro hinders the identification of their distinctive
phenotypic traits, important criteria for mollicute classification. Until
supplemental phenotypic traits become available, the genus “Candidatus
Phytoplasma” is designated, on the basis of phylogeny, as a tentative
member in the family Acholeplasmataceae. Phylogenetic analysis based
on gene sequences, in particular, ribosomal sequences, has provided
the major supporting evidence for the composition and taxonomic
subdivision of this group of organisms with diverse habitats and ecology
and has become the mainstream for the Acholeplasmataceae systematics.
However, without the ability to determine phenotypic properties, the
circumscription of related species among the non culturable members of
the family remains a major issue.
The genus Acholeplasma comprises 14 species predominantly associated
with animals and isolated from mammalian fluids but regarded as not
normally pathogenic. Conversely, the genus “Ca. Phytoplasma” includes
plant pathogens of major economic relevance worldwide. To date, 36
“Ca. Phytoplasma species” have been described