1,114 research outputs found
Elucidating the structural composition of a Fe-N-C catalyst by nuclear and electron resonance techniques
FeāNāC catalysts are very promising materials for fuel cells and metalāair batteries. This work gives fundamental insights into the structural composition of an FeāNāC catalyst and highlights the importance of an inādepth characterization. By nuclearā and electronāresonance techniques, we are able to show that even after mild pyrolysis and acid leaching, the catalyst contains considerable fractions of Ī±āiron and, surprisingly, iron oxide. Our work makes it questionable to what extent FeN4 sites can be present in FeāNāC catalysts prepared by pyrolysis at 900āĀ°C and above. The simulation of the iron partial density of phonon states enables the identification of three FeN4 species in our catalyst, one of them comprising a sixfold coordination with endāon bonded oxygen as one of the axial ligands
Investigation of hopping transport in n a Si H c Si solar cells with pulsed electrically detected magnetic resonance
Hopping transport through heterostructure solar cells based on B doped crystalline silicon wafers with highly P doped hydrogenated amorphous silicon emitters with different thicknesses is investigated at T 10 K with pulsed electrically detected magnetic resonance. The measurements show that transport is dominated by conduction band tail states g amp; 8776; 2.0046 with a distribution of their mutual coupling strength. The signal intensity correlates to the sample thickness and the g factors do not exhibit an anisotropy which suggests that transport is still dominated by bulk properties of amorphous silicon. In addition, two broad Pdonor hyperfine satellites can be detected. Influences of interface defects such as Pb like states known from silicon dioxide interfaces are either suppressed by the high Fermi energy at the interface or not presen
NMR Spectroscopy of Cell Culture, Tissues, and Other Biofluids
NMR spectroscopy can provide a wealth of information on cellular metabolism and is frequently used in metabolomics application that use cultured cells, tissues, and whole organisms. Central to these analyses are the protocols for sample harvest, which incorporate procedures for quenching metabolic processes to preserve samples in a state that is representative of their source. In this chapter, the main considerations are discussed with reference to literature exemplars. In the latter half of the chapter, less commonly studied biofluids that also have specific sample preparation requirements are discussed, with a focus on cerebrospinal fluid, faeces, bile, seminal fluid, and milk.</jats:p
Model-based comparison of organ at risk protection between VMAT and robustly optimised IMPT plans
The comparison between intensity-modulated proton therapy (IMPT) and volume-modulated arc therapy (VMAT) plans, based on models of normal tissue complication probabilities (NTCP), can support the choice of radiation modality. IMPT irradiation plans for 50 patients with head and neck tumours originally treated with photon therapy have been robustly optimised against density and setup uncertainties. The dose distribution has been calculated with a Monte Carlo (MC) algorithm. The comparison of the plans was based on dose-volume parameters in organs at risk (OARs) and NTCP-calculations for xerostomia, sticky saliva, dysphagia and tube feeding using Langendijk's model-based approach. While the dose distribution in the target volumes is similar, the IMPT plans show better protection of OARs. Therefore, it is not the high dose confirmation that constitutes the advantage of protons, but it is the reduction of the mid-to-low dose levels compared to photons. This work investigates to what extent the advantages of proton radiation are beneficial for the patient's post-therapeutic quality of life (QoL). As a result, approximately one third of the patients examined benefit significantly from proton therapy with regard to possible late side effects. Clinical data is needed to confirm the model-based calculations
Rare processes and coherent phenomena in crystals
We study coherent enhancement of Coulomb excitation of high energy particles
in crystals. We develop multiple scattering theory description of coherent
excitation which consistently incorporates both the specific resonant
properties of particle-crystal interactions and the final/initial state
interaction effects typical of the diffractive scattering. Possible
applications to observation of induced radiative neutrino transitions are
discussed.Comment: 8 pages, LaTe
Visum repertum Ć¼ber den Leichnam des seligen Herrn Hofraths Senckenberg des Stifters des BĆ¼rgerhospitals
Handschriftlicher Leichenschaubericht Ć¼ber den verunglĆ¼ckten Johann Christian Senckenberg: 18.11.1772. Unterzeichnet von den Ćrzten: Behrends, I. A. ; Krisner, I.C. ; MĆ¼ller, F. S. ; Giese, J. G. ; Behrends, J. C. ; Jonas, A. I. G. ; Meyer, C. F. ; Bucher, J. L. ; Grasemann, Ch. F
The BioGRID Interaction Database: 2011 update
The Biological General Repository for Interaction Datasets (BioGRID) is a public database that archives and disseminates genetic and protein
interaction data from model organisms and humans
(http://www.thebiogrid.org). BioGRID currently holds 347 966
interactions (170 162 genetic, 177 804 protein) curated from both
high-throughput data sets and individual focused studies, as derived
from over 23 000 publications in the primary literature. Complete
coverage of the entire literature is maintained for budding yeast
(Saccharomyces cerevisiae), fission yeast (Schizosaccharomyces pombe)
and thale cress (Arabidopsis thaliana), and efforts to expand curation
across multiple metazoan species are underway. The BioGRID houses 48
831 human protein interactions that have been curated from 10 247
publications. Current curation drives are focused on particular areas
of biology to enable insights into conserved networks and pathways that
are relevant to human health. The BioGRID 3.0 web interface contains
new search and display features that enable rapid queries across
multiple data types and sources. An automated Interaction Management
System (IMS) is used to prioritize, coordinate and track curation
across international sites and projects. BioGRID provides interaction
data to several model organism databases, resources such as Entrez-Gene
and other interaction meta-databases. The entire BioGRID 3.0 data
collection may be downloaded in multiple file formats, including PSI MI
XML. Source code for BioGRID 3.0 is freely available without any
restrictions
One-pion transitions between heavy baryons in the constituent quark model
Single pion transitions of S wave to S wave, P wave to S wave and P wave to P
wave heavy baryons are analyzed in the framework of the Heavy Quark Symmetry
limit (HQS). We use a constituent quark model picture for the light diquark
system with an underlying SU(2N_{f}) X O(3) symmetry to reduce the number of
the HQS coupling factors required to describe these transitions. We also use
the quantum theory of angular momentum to rewrite the one-pion transitions
constituent quark model results in a more general form using the 6j- and
9j-symbols. We finally estimate the decay rates of some single pion transitions
between charm baryon states.Comment: Latex, 33 pages including 2 figures (Postscript). Some typos are
corrected with minor changes. Two references were added to the final version
which will appear in Phy. Rev.
New Approach for Measuring at Future -Factories
It is suggested that the measurements of hadronic invariant mass ()
distributons in the inclusive decays can be
useful in extracting the CKM matrix element . We investigated
hadronic invariant mass distributions within the various theoretical models of
HQET, FAC and chiral lagrangian as well as ACCMM model. It is also emphasized
that the distribution even at the region in the inclusive
are effetive in selecting the events, experimentally viable at
the future asymmetric factories, with better theoretical understandings.Comment: 11 pages not including 1 figur
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