791 research outputs found
Pressure-induced transition from the dynamic to static Jahn-Teller effect in (PhP)IC
High-pressure infrared transmission measurements on \PhC60 were performed up
to 9 GPa over a broad frequency range (200 - 20000 cm) to monitor the
vibrational and electronic/vibronic excitations under pressure. The four
fundamental T modes of \C60a\ are split into doublets already at the
lowest applied pressure and harden with increasing pressure. Several cation
modes and fullerene-related modes split into doublets at around 2 GPa, the most
prominent one being the G mode. The splitting of the vibrational modes
can be attributed to the transition from the dynamic to static Jahn-Teller
effect, caused by steric crowding at high pressure. Four absorption bands are
observed in the NIR-VIS frequency range. They are discussed in terms of
transitions between LUMO electronic states in \C60a, which are split because of
the Jahn-Teller distortion and can be coupled with vibrational modes. Various
distortions and the corresponding symmetry lowering are discussed. The observed
redshift of the absorption bands indicates that the splitting of the LUMO
electronic states is reduced upon pressure application.Comment: 10 pages, 17 figure
The Effect of Continuous Suspension Constraint on the Free Vibration and Buckling of a Beam
In this paper, the free vibration and the buckling of a continuously suspended simply-supported beam are analyzed. A semi-analytical approach is used to calculate the natural circular frequencies and the critical forces of the beam. The length of the suspension is used as a parameter, and the natural circular frequencies and the critical forces are presented in a frequency map or a buckling map. The maps are analyzed in view of the trivial solutions, and the frequency map is compared to the map of discrete cable-stayed beams. Finally, for the validation of the results a numerical, finite element analysis is performed
Phenolic contents, antioxidant properties, and sensory profiles of wheat round rolls supplemented with whole grain cereals
Whole cereal flours (buckwheat, barley, and oat) and wheat bran were used to substitute 20% of white bakery wheat flour to prepare round rolls. Round roll quality was evaluated by determining total phenolic and total flavonoid contents, antioxidative capacity, the content of lipid hydroperoxides (primary oxidation products), and sensory profiling. Moreover, the stability of the phenolic compounds and antioxidant behaviour throughout processing was studied. Technological processing does not cause any significant loss of phenolics (less than 5%). A significant increase in antioxidants and phenolics of the flour mixtures and final products were observed compared to those of white wheat round rolls (as control). Buckwheat and barley round roll crumbs contained the highest total phenolic and total flavonoid contents, and were the most effective in enhancing antioxidant activity, which increased 15-fold and 8-fold, respectively, when compared to the control roll. The tested cereals effectively retarded formation of lipid hydroperoxides (from over 50% to control), which are undesirable from both a nutrition and storage/shelf life perspective. The results of sensory analyses showed that such bakery products are accepted by consumers with the exception of the product made with oat flour, where a reduction in the oat content would be preferable
Possible observation of phase coexistence of the fractional quantum Hall liquid and a solid
We have measured the magnetoresistance of a very low density and an extremely
high quality two-dimensional hole system. With increasing magnetic field
applied perpendicularly to the sample we observe the sequence of insulating,
fractional quantum Hall liquid, and insulating phases. In both of the
insulating phases in the vicinity of the filling the
magnetoresistance has an unexpected oscillatory behavior with the magnetic
field. These oscillations are not of the Shubnikov-de Haas type and cannot be
explained by spin effects. They are most likely the consequence of the
formation of a new electronic phase which is intermediate between the
correlated Hall liquid and a disorder pinned solid.Comment: 5 pages, 4 figure
dUTPase based switch controls transfer of virulence genes in order to preserve integrity of the transferred mobile genetic elements
dUTPases ubiquitously regulate cellular dUTP levels to preserve
genome integrity. Recently, several other cellular processes were
reported to be controlled by dUTPases including the horizontal
transfer of Staphylococcus aureus pathogenicity islands (SaPI).
SaPIs are mobil genetic elements that encode virulence enhancing
factors e.g. toxins. Here, phage dUTPases were proposed to
counteract the repressor protein (Stl) and promote SaPI excision
and transfer. A G protein-like mechanism was proposed which is
unexpected in light of the kinetic mechanism of dUTPase.
Here we investigate the molecular mechanism of SaPI transfer
regulation, using numerous dUTPase variants and a wide range
of in vitro methods (steady-state and transient kinetics, VIS and
fluorescence spectroscopy, EMSA, quartz crystal microbalance,
X-ray crystallography).
Our results unambiguously show that Stl inhibits the enzymatic
activity of dUTPase in the nM concentration range and
dUTP strongly inhibits the dUTPase: Stl complexation. These
results identify Stl as a highly potent dUTPase inhibitor protein
and disprove the G protein-like mechanism. Importantly, our
results clearly show that the dUTPase:dUTP complex is inaccessible
to the Stl repressor. Unlike in small GTPases, hydrolysis of
the substrate nucleoside triphosphate (dUTP in this case) is
required prior to the interaction with the partner (Stl repressor in
this case). We propose that dUTPase can efficiently interact with
Stl and induce SaPI excision only if the cellular dUTP level is low (i.e. when dUTPase resides mainly in the apo enzyme form)
while high dUTP levels would inhibit SaPI transfer. This mechanism
may serve the preservation of the integrity of the transferred
SaPI genes and links the well-known metabolic role of
dUTPases to their newly revealed regulatory function in spread
of virulence factors
Wang Bi\u27s Annotation on Laozi\u27s Place in China and Japan: Focusing on Ogyu Sorai
Wang Bi\u27s Annotation on Laozi 『老子』王弼注 is considered one of the representative notes on Laozi. In Chinahowever, it was not until 1781 when this book was included in Sikuquanshu 『四庫全書』 that the study of Wang Bi\u27s note became popular. In Japan, while Wang Bi\u27s note was introduced before the 5th century, it received rare recognition until Okada Touin\u27s Laozi Daodejing Annotated by Wang Bi 岡田東贇 『老子道徳経王弼注』 published in 1734. However, further research reveals that Ogyu Sorai 荻生徂徠 had pointed out in Keishishiyohran 『経子史要覧』 that, in reading Laozi from the view of classical rhetoric 古文辞学 Wang Bi\u27s annotation should be referred to. Keishishiyohran was based on Sorai\u27s dictation before 1728, and it was earlier than both Okada Touin\u27s Laozi Annotated by Wang Bi (1734) and Sikuquanshu (1781). Therefore< judging from evidences currently available, it seems fair to conclude that Sorai was the pioneer who introduced Wang Bi\u27s annotation into the field of Laozi studies
Phenotyping under extreme weather conditions and microsatellite based genotyping of some Hungarian grape cultivars
Phenology is an indicator of plant response to the environment. In viticulture growth stages timing is important for site and cultivar selection, vineyard planning and cultural practices management. In the last years, autochthonous cultivars obtained an increased interest and, therefore, in this work we studied the phenological performances of Hungarian old varieties. The data recorded in 2012 were compared with the ones published 60 years ago. The examined genotypes were identified by SSR markers. Extremely high temperature and low precipitation occurred during the 2012 vintage. The uncommon weather conditions affected the length of the vegetation period less than expected. However, the time period between flowering and harvest decreased significantly. In general, minor varieties seem to be more sensitive to extreme conditions than international cultivars, according to their eno-carpological characteristics
Complex nanostructures in diamond
Meteoritic diamonds and synthesized diamond-related materials contain a wide variety of complex nanostructures. This Comment highlights and classifies this structural complexity by a systematic hierarchical approach, and discusses the perspectives on nanostructure and properties engineering of diamond-related materials
- …