8 research outputs found
Molecular Beam Epitaxy growth of MoTe on Hexagonal Boron Nitride
Hexagonal boron nitride has already been proven to serve as a decent
substrate for high quality epitaxial growth of several 2D materials, such as
graphene, MoSe, MoS or
WSe. Here, we present for the first time the molecular
beam epitaxy growth of MoTe on atomically smooth
hexagonal boron nitride (hBN) substrate. Occurrence of
MoTe in various crystalline phases such as distorted
octahedral 1T' phase with semimetal properties or hexagonal 2H phase with
semiconducting properties opens a possibility of realisation of crystal-phase
homostructures with tunable properties. Atomic force microscopy studies of
MoTe grown in a single monolayer regime enable us to
determine surface morphology as a function of the growth conditions. The
diffusion constant of MoTe grown on hBN can be altered 5
times by annealing after the growth, reaching about 5 10
cm/s. Raman spectroscopy results suggest a coexistence of both 2H and 1T'
MoTe phases in the studied samples.Comment: 6 pages, 3 figure
Virulence factors of Moraxella catarrhalis outer membrane vesicles are major targets for cross-reactive antibodies and have adapted during evolution
Moraxella catarrhalis is a common human respiratory tract pathogen. Its virulence factors associated with whole bacteria or outer membrane vesicles (OMVs) aid infection, colonization and may induce specific antibodies. To investigate pathogen-host interactions, we applied integrated bioinformatic and immunoproteomic (2D-electrophoresis, immunoblotting, LC-MS/MS) approaches. We showed that OMV proteins engaged exclusively in complement evasion and colonization strategies, but not those involved in iron transport and metabolism, are major targets for cross-reacting antibodies produced against phylogenetically divergent M. catarrhalis strains. The analysis of 31 complete genomes of M. catarrhalis and other Moraxella revealed that OMV protein-coding genes belong to 64 orthologous groups, five of which are restricted to M. catarrhalis. This species showed a two-fold increase in the number of OMV protein-coding genes relative to its ancestors and animal-pathogenic Moraxella. The appearance of specific OMV factors and the increase in OMV-associated virulence proteins during M. catarrhalis evolution is an interesting example of pathogen adaptation to optimize colonization. This precisely targeted cross-reactive immunity against M. catarrhalis may be an important strategy of host defences to counteract this phenomenon. We demonstrate that cross-reactivity is closely associated with the anti-virulent antibody repertoire which we have linked with adaptation of this pathogen to the host
Natural exceptional points in the excitation spectrum of a light-matter system
We observe natural exceptional points in the excitation spectrum of an
exciton-polariton system by optically tuning the light-matter interactions. The
observed exceptional points do not require any spatial or polarization degrees
of freedom and result solely from the transition from weak to strong
light-matter coupling. We demonstrate that they do not coincide with the
threshold for photon lasing, confirming previous theoretical predictions [Phys.
Rev. Lett. 122, 185301 (2019), Optica 7, 1015 (2020) ]. Using a technique where
a strong coherent laser pump induces up-converted excitations, we encircle the
exceptional point in the parameter space of coupling strength and particle
momentum. Our method of local optical control of light-matter coupling paves
the way to investigation of fundamental phenomena including dissipative phase
transitions and non-Hermitian topological states
Impact of marathon performance on muscles stiffness in runners over 50âyears old
IntroductionThe research examines the relationship between marathon performance and muscle stiffness changes from pre to marathon in recreational runners aged 50+ years.MethodsThirty-one male long-distance runners aged 50â73 years participated in the experiment. The muscle stiffness of quadriceps and calves was measured in two independent sessions: the day before the marathon and 30âmin after the completed marathon run using a Myoton device.Results and DiscussionThe 42.195-km run was completed in 4.30,05 h ± 35.12 min, which indicates an intensity of 79.3% ± 7.1% of HRmax. The long-term, low-intensity running exercise (marathon) in older recreational runners and the low level of HRmax and VO2max showed no statistically significant changes in muscle stiffness (quadriceps and calves). There was reduced muscle stiffness (p = 0.016), but only in the triceps of the calf in the dominant (left) leg. Moreover, to optimally evaluate the marathon and adequately prepare for the performance training program, we need to consider the direct and indirect analyses of the running economy, running technique, and HRmax and VO2max variables. These variables significantly affect marathon exercise
Hypoxic tachycardia is not a result of increased respiratory activity in healthy subjects
Narrow Excitonic Lines and Large-Scale Homogeneity of Transition-Metal Dichalcogenide Monolayers Grown by Molecular Beam Epitaxy on Hexagonal Boron Nitride
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