816 research outputs found
Optically induced coherent intra-band dynamics in disordered semiconductors
On the basis of a tight-binding model for a strongly disordered semiconductor
with correlated conduction- and valence band disorder a new coherent dynamical
intra-band effect is analyzed. For systems that are excited by two, specially
designed ultrashort light-pulse sequences delayed by tau relatively to each
other echo-like phenomena are predicted to occur. In addition to the inter-band
photon echo which shows up at exactly t=2*tau relative to the first pulse, the
system responds with two spontaneous intra-band current pulses preceding and
following the appearance of the photon echo. The temporal splitting depends on
the electron-hole mass ratio. Calculating the population relaxation rate due to
Coulomb scattering, it is concluded that the predicted new dynamical effect
should be experimentally observable in an interacting and strongly disordered
system, such as the Quantum-Coulomb-Glass.Comment: to be published in Physical Review B15 February 200
High-resolution measurement of the time-modulated orbital electron capture and of the decay of hydrogen-like Pm ions
The periodic time modulations, found recently in the two-body orbital
electron-capture (EC) decay of both, hydrogen-like Pr and
Pm ions, with periods near to 7s and amplitudes of about 20%,
were re-investigated for the case of Pm by using a 245 MHz
resonator cavity with a much improved sensitivity and time resolution. We
observed that the exponential EC decay is modulated with a period s, in accordance with a modulation period s as obtained
from simultaneous observations with a capacitive pick-up, employed also in the
previous experiments. The modulation amplitudes amount to and
for the 245 MHz resonator and the capacitive pick-up,
respectively. These new results corroborate for both detectors {\it exactly}
our previous findings of modulation periods near to 7s, though with {\it
distinctly smaller} amplitudes. Also the three-body decays have been
analyzed. For a supposed modulation period near to 7s we found an amplitude , compatible with and in agreement with the preliminary
result of our previous experiment. These observations could
point at weak interaction as origin of the observed 7s-modulation of the EC
decay. Furthermore, the data suggest that interference terms occur in the
two-body EC decay, although the neutrinos are not directly observed.Comment: In memoriam of Prof. Paul Kienle, 9 pages, 1 table, 5 figures Phys.
Lett. B (2013) onlin
PYOGENIC GRANULOMAS IN THE ORAL CAVITY: A SERIES OF CASES
Introduction: Pyogenic granulomas represent tumour-like lesions affecting the skin and the oral cavity. This classic definition can be somewhat misleading because such lesion is not associated with infection and lacks any clinical evidence of pus or histological evidence of actual granulation tissue. Scientific literature sources estimate its prevalence to 1:25000 per capita, affecting females twice as often. Pyogenic granuloma in the oral cavity affects the interdental papilla in 70% of the cases.
Purpose: The authors present a case series of pyogenic granulomas in the oral cavity with varying localization and therapeutic approach.
Materials and methods: This article presents six clinical cases of PG. Diagnosis is challenging due to similarities with a number of tumorous and non-tumorous neoplasms (formations) in the oral cavity. Two histological types of pyogenic granuloma can be identified: lobular and non-lobular capillary hemangioma. Surgical excision is the treatment method of choice, followed by deep curettage of the lesion toward the underlying bone. Such precautions are necessary because 15,8% of the lesions tend to recur over time.
Results: Alternative therapeutic approaches for removal of PG are explored, which are aimed at reducing the recurrences after surgical treatment. Such an opportunity is provided by utilization of Er:Yag laser because its effect can reach the underlying bone.
Conclusion: Pyogenic granuloma represents a diagnostic challenge, specifically in cases of atypical localization. The effective surgical approach requires complete removal of the pathological process from the surrounding healthy structures in order to prevent recurrences
Beyond Controlled Environments: 3D Camera Re-Localization in Changing Indoor Scenes
Long-term camera re-localization is an important task with numerous computer
vision and robotics applications. Whilst various outdoor benchmarks exist that
target lighting, weather and seasonal changes, far less attention has been paid
to appearance changes that occur indoors. This has led to a mismatch between
popular indoor benchmarks, which focus on static scenes, and indoor
environments that are of interest for many real-world applications. In this
paper, we adapt 3RScan - a recently introduced indoor RGB-D dataset designed
for object instance re-localization - to create RIO10, a new long-term camera
re-localization benchmark focused on indoor scenes. We propose new metrics for
evaluating camera re-localization and explore how state-of-the-art camera
re-localizers perform according to these metrics. We also examine in detail how
different types of scene change affect the performance of different methods,
based on novel ways of detecting such changes in a given RGB-D frame. Our
results clearly show that long-term indoor re-localization is an unsolved
problem. Our benchmark and tools are publicly available at
waldjohannau.github.io/RIO10Comment: ECCV 2020, project website https://waldjohannau.github.io/RIO1
Neurotensin(8–13) analogs as dual NTS1 and NTS2 receptor ligands with enhanced effects on a mouse model of Parkinson's disease
: The modulatory interactions between neurotensin (NT) and the dopaminergic neurotransmitter system in the brain suggest that NT may be associated with the progression of Parkinson's disease (PD). NT exerts its neurophysiological effects by interactions with the human NT receptors type 1 (hNTS1) and 2 (hNTS2). Therefore, both receptor subtypes are promising targets for the development of novel NT-based analogs for the treatment of PD. In this study, we used a virtually guided molecular modeling approach to predict the activity of NT(8-13) analogs by investigating the docking models of ligands designed for binding to the human NTS1 and NTS2 receptors. The importance of the residues at positions 8 and/or 9 for hNTS1 and hNTS2 receptor binding affinity was experimentally confirmed by radioligand binding assays. Further in vitro ADME profiling and in vivo studies revealed that, compared to the parent peptide NT(8-13), compound 10 exhibited improved stability and BBB permeability combined with a significant enhancement of the motor function and memory in a mouse model of PD. The herein reported NTS1/NTS2 dual-specific NT(8-13) analogs represent an attractive tool for the development of therapeutic strategies against PD and potentially other CNS disorders
Isomeric excitation energy for In from mass spectrometry reveals constant trend next to doubly magic Sn
The excitation energy of the 1/2 isomer in In at is
measured to be 671(37) keV and the mass uncertainty of the 9/2 ground state
is significantly reduced using the ISOLTRAP mass spectrometer at ISOLDE/CERN.
The measurements exploit a major improvement in the resolution of the
multi-reflection time-of-flight mass spectrometer. The results reveal an
intriguing constancy of the isomer excitation energies in
neutron-deficient indium that persists down to the shell closure, even
when all neutrons are removed from the valence shell. This trend is used to
test large-scale shell model, \textit{ab initio}, and density functional theory
calculations. The models have difficulties describing both the isomer
excitation energies and ground-state electromagnetic moments along the indium
chain.Comment: 13 pages, 4 figure
Spintronics: Fundamentals and applications
Spintronics, or spin electronics, involves the study of active control and
manipulation of spin degrees of freedom in solid-state systems. This article
reviews the current status of this subject, including both recent advances and
well-established results. The primary focus is on the basic physical principles
underlying the generation of carrier spin polarization, spin dynamics, and
spin-polarized transport in semiconductors and metals. Spin transport differs
from charge transport in that spin is a nonconserved quantity in solids due to
spin-orbit and hyperfine coupling. The authors discuss in detail spin
decoherence mechanisms in metals and semiconductors. Various theories of spin
injection and spin-polarized transport are applied to hybrid structures
relevant to spin-based devices and fundamental studies of materials properties.
Experimental work is reviewed with the emphasis on projected applications, in
which external electric and magnetic fields and illumination by light will be
used to control spin and charge dynamics to create new functionalities not
feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes
from the published versio
Bound -state β- -decay of bare 205 Tl 81+
Beta decay into bound electron states of the daughter atom accompanied by the emission of a monochromatic antineutrino, has been predicted by Daudel et al.[1]. However, a noteworthy probability of βb- decay exists only for highly-charged ions, which makes its observation rather difficult
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