307 research outputs found
Structure of strongly coupled, multi-component plasmas
We investigate the short-range structure in strongly coupled fluidlike plasmas using the hypernetted chain approach generalized to multicomponent systems. Good agreement with numerical simulations validates this method for the parameters considered. We found a strong mutual impact on the spatial arrangement for systems with multiple ion species which is most clearly pronounced in the static structure factor. Quantum pseudopotentials were used to mimic diffraction and exchange effects in dense electron-ion systems. We demonstrate that the different kinds of pseudopotentials proposed lead to large differences in both the pair distributions and structure factors. Large discrepancies were also found in the predicted ion feature of the x-ray scattering signal, illustrating the need for comparison with full quantum calculations or experimental verification
Laser-Cluster-Interaction in a Nanoplasma-Model with Inclusion of Lowered Ionization Energies
The interaction of intense laser fields with silver and argon clusters is
investigated theoretically using a modified nanoplasma model. Single pulse and
double pulse excitations are considered. The influence of the dense cluster
environment on the inner ionization processes is studied including the lowering
of the ionization energies. There are considerable changes in the dynamics of
the laser-cluster interaction. Especially, for silver clusters, the lowering of
the ionization energies leads to increased yields of highly charged ions.Comment: 10 pages, 11 figure
Partially ionized plasmas in electromagnetic fields
The interaction of partially ionized plasmas with an electromagnetic field is
investigated using quantum statistical methods. A general statistical
expression for the current density of a plasma in an electromagnetic field is
presented and considered in the high field regime. Expressions for the
collisional absorption are derived and discussed. Further, partially ionized
plasmas are considered. Plasma Bloch equations for the description of
bound-free transitions are given and the absorption coefficient as well as rate
coefficients for multiphoton ionization are derived and numerical results are
presented.Comment: 18 pages, 8 figures, accepted for publication in J. Phys.: Conf. Se
Determinants of DNA yield and purity collected with buccal cell samples
Buccal cells are an important source of DNA in epidemiological studies, but little is known about factors that influence amount and purity of DNA. We assessed these factors in a self-administered buccal cell collection procedure, obtained with three cotton swabs. In 2,451 patients DNA yield and in 1,033 patients DNA purity was assessed. Total DNA yield ranged from 0.08 to 1078.0 μg (median 54.3 μg; mean 82.2 μg ± SD 92.6). The median UV 260:280 ratio, was 1.95. Samples from men yielded significantly more DNA (median 58.7 μg) than those from women (median 44.2 μg). Diuretic drug users had significantly lower purity (median 1.92) compared to other antihypertensive drug users (1.95). One technician obtained significantly lower DNA yields. Older age was associated with lower DNA purity. In conclusion, DNA yield from buccal swabs was higher in men and DNA purity was associated with age and the use of diuretics
Unintentional high density p-type modulation doping of a GaAs/AlAs core-multi-shell nanowire
Achieving significant doping in GaAs/AlAs core/shell nanowires (NWs) is of
considerable technological importance but remains a challenge due to the
amphoteric behavior of the dopant atoms. Here we show that placing a narrow
GaAs quantum well in the AlAs shell effectively getters residual carbon
acceptors leading to an \emph{unintentional} p-type doping. Magneto-optical
studies of such a GaAs/AlAs core multi-shell NW reveal quantum confined
emission. Theoretical calculations of NW electronic structure confirm quantum
confinement of carriers at the core/shell interface due to the presence of
ionized carbon acceptors in the 1~nm GaAs layer in the shell.
Micro-photoluminescence in high magnetic field shows a clear signature of
avoided crossings of the Landau level emission line with the Landau
level TO phonon replica. The coupling is caused by the resonant hole-phonon
interaction, which points to a large 2D hole density in the structure.Comment: just published in Nano Letters
(http://pubs.acs.org/doi/full/10.1021/nl500818k
Association of polymorphisms in the beta-2 adrenergic receptor gene with fracture risk and bone mineral density
Summary: Signaling through the beta-2 adrenergic receptor (B2AR) on the osteoblast influences bone remodeling in rodents. In the B2AR gene, three polymorphisms influence receptor function. We show that these polymorphisms are not associated with fracture risk or bone mineral density in the UCP, Rotterdam Study, and GEFOS cohorts. Introduction: Signaling through the beta-2 adrenergic receptor (B2AR) on the osteoblast influences bone remodeling in rodents. In the B2AR gene, three polymorphisms are known to influence receptor function in vitro and in vivo (rs1042713, rs1042714, and rs1800888). We examined the role of these polymorphisms in the B2AR gene on human bone metabolism. Methods: We performed nested case–control studies to determine the association of these polymorphisms with fracture risk in the Utrecht Cardiovascular Pharmacogenetics (UCP) cohort and in three cohorts of the Rotterdam Study. We also determined the association of these polymorphisms with bone mineral density (BMD) in the GEFOS Consortium. UCP contains drug-dispensing histories from community pharmacies linked to national registrations of hospital discharges in the Netherlands. The Rotterdam Study is a prospective cohort study investigating demographics and risk factors of chronic diseases. GEFOS is a large international collaboration studying the genetics of osteoporosis. Fractures were defined by ICD-9 codes 800–829 in the UCP cohort (158 cases and 2617 unmatched controls) and by regular X-ray examinations, general practitioner, and hospital records in the Rotterdam Study (2209 cases and 8559 unmatched controls). BMD was measured at the femoral neck and lumbar spine using dual-energy X-ray absorptiometry in GEFOS (N = 32,961). Results: Meta-analysis of the two nested case–control studies showed pooled odds ratios of 0.98 (0.91–1.05, p = 0.52), 1.04 (0.97–1.12, p = 0.28), and 1.16 (0.83–1.62, p = 0.38) for the associations betwee
Drug-Induced Liver Injury due to Flucloxacillin:Relevance of Multiple Human Leukocyte Antigen Alleles
© 2019 The Authors Clinical Pharmacology & Therapeutics © 2019 American Society for Clinical Pharmacology and Therapeutics Some patients prescribed flucloxacillin (~0.01%) develop drug-induced liver injury (DILI). HLA-B*57:01 is an established genetic risk factor for flucloxacillin DILI. To consolidate this finding, identify additional genetic factors, and assess relevance of risk factors for flucloxacillin DILI in relation to DILI due to other penicillins, we performed a genomewide association study involving 197 flucloxacillin DILI cases and 6,835 controls. We imputed single-nucleotide polymorphism and human leukocyte antigen (HLA) genotypes. HLA-B*57:01 was the major risk factor (allelic odds ratio (OR)=36.62; P=2.67×10−97). HLA-B*57:03 also showed an association (OR=79.21; P=1.2×10−6). Within the HLA-B protein sequence, imputation showed valine97, common to HLA-B*57:01 and HLA-B*57:03, had the largest effect (OR=38.1; P=9.7×10−97). We found no HLA-B*57 association with DILI due to other isoxazolyl penicillins (n=6) or amoxicillin (n=15) and no significant non-HLA signals for any penicillin-related DILI
Towards a data publishing framework for primary biodiversity data: challenges and potentials for the biodiversity informatics community
Background: Currently primary scientific data, especially that dealing with biodiversity, is neither
easily discoverable nor accessible. Amongst several impediments, one is a lack of professional
recognition of scientific data publishing efforts. A possible solution is establishment of a ‘Data
Publishing Framework’ which would encourage and recognise investments and efforts by
institutions and individuals towards management, and publishing of primary scientific data
potentially on a par with recognitions received for scholarly publications.
Discussion: This paper reviews the state-of-the-art of primary biodiversity data publishing, and
conceptualises a ‘Data Publishing Framework’ that would help incentivise efforts and investments by
institutions and individuals in facilitating free and open access to biodiversity data. It further
postulates the institutionalisation of a ‘Data Usage Index (DUI)’, that would attribute due recognition
to multiple players in the data collection/creation, management and publishing cycle.
Conclusion: We believe that institutionalisation of such a ‘Data Publishing Framework’ that
offers socio-cultural, legal, technical, economic and policy environment conducive for data
publishing will facilitate expedited discovery and mobilisation of an exponential increase in quantity
of ‘fit-for-use’ primary biodiversity data, much of which is currently invisible
Electron–ion collision rates in atomic clusters irradiated by femtosecond laser pulses
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