158 research outputs found
Major abdominal surgery in Jehovah’s Witnesses
Introduction
Patients who are Jehovah’s Witnesses pose difficult ethical and moral dilemmas for surgeons because of their refusal to receive blood and blood products. This article outlines the personal experiences of six Jehovah’s Witnesses who underwent major abdominal surgery at a single institution and also summarises the literature on the perioperative care of these patients.
Methods
The patients recorded their thoughts and the dilemmas they faced during their surgical journey. We also reviewed the recent literature on the ethical principles involved in treating such patients and strategies recommended to make surgery safer.
Results
All patients were supported in their decision making by the clinical team and the Hospital Liaison Committee for Jehovah’s Witnesses. The patients recognised the ethical and moral difficulties experienced by clinicians in this setting. However, they described taking strength from their belief in Jehovah. A multitude of techniques are available to minimise the risk associated with major surgery in Jehovah’s Witness patients, many of which have been adopted to minimise unnecessary use of blood products in general. Nevertheless, the risks of catastrophic haemorrhage and consequent mortality remain an unresolved issue for the treating team.
Conclusions
Respect for a patient’s autonomy in this setting is the overriding ethical principle, with detailed discussion forming an important part of the preparation of a Jehovah’s Witness for major abdominal surgery. Clinicians must be diligent in the documentation of the patient’s wishes to ensure all members of the team can abide by these
Fragmentation in Peripheral Heavy-Ion Collisions: from Neck Emission to Spectator Decays
Invariant cross sections of intermediate mass fragments in peripheral
collisions of Au on Au at incident energies between 40 and 150 AMeV have been
measured with the 4-pi multi-detector INDRA. The maximum of the fragment
production is located near mid-rapidity at the lower energies and moves
gradually towards the projectile and target rapidities as the energy is
increased. Schematic calculations within an extended Goldhaber model suggest
that the observed cross-section distributions and their evolution with energy
are predominantly the result of the clustering requirement for the emerging
fragments and of their Coulomb repulsion from the projectile and target
residues. The quantitative comparison with transverse energy spectra and
fragment charge distributions emphasizes the role of hard scattered nucleons in
the fragmentation process.Comment: 5 pages, 5 eps figures, RevTeX4, submitted to Phys. Lett.
Thermal and Chemical Freeze-out in Spectator Fragmentation
Isotope temperatures from double ratios of hydrogen, helium, lithium,
beryllium, and carbon isotopic yields, and excited-state temperatures from
yield ratios of particle-unstable resonances in 4He, 5Li, and 8Be, were
determined for spectator fragmentation, following collisions of 197Au with
targets ranging from C to Au at incident energies of 600 and 1000 MeV per
nucleon. A deviation of the isotopic from the excited-state temperatures is
observed which coincides with the transition from residue formation to
multi-fragment production, suggesting a chemical freeze-out prior to thermal
freeze-out in bulk disintegrations.Comment: 14 pages, 10 figures, submitted to Phys. Rev. C, small changes as
suggested by the editors and referee
Statistical Multifragmentation of Non-Spherical Expanding Sources in Central Heavy-Ion Collisions
We study the anisotropy effects measured with INDRA at GSI in central
collisions of Xe+Sn at 50 A.MeV and Au+Au at 60, 80, 100 A.MeV incident energy.
The microcanonical multifragmentation model with non-spherical sources is used
to simulate an incomplete shape relaxation of the multifragmenting system. This
model is employed to interpret observed anisotropic distributions in the
fragment size and mean kinetic energy. The data can be well reproduced if an
expanding prolate source aligned along the beam direction is assumed. An either
non-Hubblean or non-isotropic radial expansion is required to describe the
fragment kinetic energies and their anisotropy. The qualitative similarity of
the results for the studied reactions suggests that the concept of a
longitudinally elongated freeze-out configuration is generally applicable for
central collisions of heavy systems. The deformation decreases slightly with
increasing beam energy.Comment: 35 pages, 19 figures, submitted to Nuclear Physics
Examining the distribution and impact of single nucleotide polymorphisms in the capsular locus of Streptococcus pneumoniae serotype 19A
Streptococcus pneumoniae serotype 19A prevalence has increased after implementation of PCV7 and PCV10 vaccines. In this study, we have provided, with high accuracy, the genetic diversity of the 19A serotype in a cohort of Dutch invasive pneumococcal disease patients and asymptomatic carriers obtained in the period 2004-2016. Whole genomes of the 338 pneumococcal isolates in this cohort were sequenced and their capsule (cps) loci compared to examine the diversity and determine the impact on the production of CPS sugar precursors and CPS shedding. We discovered 79 types with a unique CPS locus sequence. Most variation was observed in the rmlB and rmlD genes of the TDP-Rha synthesis pathway, and in the wzg gene, of unknown function. Interestingly, gene variation in the cps locus was conserved in multiple alleles. Using RmlB and RmlD protein models, we predict that enzymatic function is not affected by the single nucleotide polymorphisms as identified. To determine if RmlB and RmlD function was affected, we analyzed nucleotide sugar levels using UHPLC-MS. CPS precursors differed between 19A cps locus subtypes, including TDP-Rha, but no clear correlation was observed. Also, a significant difference in multiple nucleotide sugar levels was observed between phylogenetically branched groups. Because of indications of a role for Wzg in capsule shedding, we analyzed if this was affected. No clear indication of a direct role in shedding was found. We thus describe genotypic variety in rmlB, rmlD and wzg in serotype 19A the Netherlands, for which we have not discovered an associated phenotype
Measurement of the Reaction in Search for the Recently Observed Resonance Structure in and systems
Exclusive measurements of the quasi-free reaction have
been performed by means of collisions at = 1.2 GeV using the WASA
detector setup at COSY. Total and differential cross sections have been
obtained covering the energy region = (2.35 - 2.46) GeV, which
includes the region of the ABC effect and its associated resonance structure.
No ABC effect, {\it i.e.} low-mass enhancement is found in the
-invariant mass spectrum -- in agreement with the constraint from
Bose statistics that the isovector pion pair can not be in relative s-wave. At
the upper end of the covered energy region -channel processes for Roper,
and excitations provide a reasonable description
of the data, but at low energies the measured cross sections are much larger
than predicted by such processes. Adding a resonance amplitude for the
resonance at =~2.37 GeV with =~70 MeV and observed
recently in and reactions leads to an
agreement with the data also at low energies
Neutron-Proton Scattering in the Context of the (2380) Resonance
New data on quasifree polarized neutron-proton scattering, in the region of
the recently observed resonance structure, have been obtained by
exclusive and kinematically complete high-statistics measurements with WASA at
COSY. This paper details the determination of the beam polarization, checks of
the quasifree character of the scattering process, on all obtained
angular distributions and on the new partial-wave analysis, which includes the
new data producing a resonance pole in the - coupled partial
waves at () MeV -- in accordance with the dibaryon
resonance hypothesis. The effect of the new partial-wave solution on the
description of total and differential cross section data as well as specific
combinations of spin-correlation and spin-transfer observables available from
COSY-ANKE measurements at = 2.27 GeV is discussed
Search for a dark photon in the decay
The presently world largest data sample of pi0 --> gamma e+e- decays
containing nearly 5E5 events was collected using the WASA detector at COSY. A
search for a dark photon U produced in the pi0 --> gamma U --> gamma e+e- decay
from the pp-->pp\pi^0 reaction was carried out. An upper limit on the square of
the U-gamma mixing strength parameter epsilon^2 of 5e-6 at 90% CL was obtained
for the mass range 20 MeV <M_U< 100 MeV. This result together with other recent
experimental limits significantly reduces the M_U vs. \epsilon^2 parameter
space preferred by the measured value of the muon anomalous magnetic moment.Comment: 16 pages, 8 figures; improved analysis extending the exclusion region
to 20 MeV<M_U< 100 MeV; implemented changes requested by referee
Systematics of Stopping and Flow in Au+Au Collisions
Excitation functions of flow and stopping observables for the Au+Au system at
energies from 40 to 1500 MeV per nucleon are presented. The systematics were
obtained by merging the results of the INDRA and FOPI experiments, both
performed at the GSI facility. The connection to the nuclear equation of state
is discussed.Comment: Contribution to the WCI book "Dynamics and Thermodynamics with
Nucleonic Degrees of Freedom
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