125 research outputs found
Biomedical ethics: The ethical implications of mass immunization.
Mass immunization is distinct from other medical practices in that healthy individuals assume largely unknown risks with no goal of improving their present state of health. Vaccinees face the very real prospect of vaccine-related adverse effects, some permanently debilitating or even fatal, for a promise of future health protection even when no immediate or direct threat to health exists. Mass immunization has always met with some measure of opposition. What is new about the current controversy is that many physicians, nurses, and medical researchers have articulated their own opposing viewpoints supported by factual evidence. Mass immunization presents a vital, and largely ignored, area of inquiry for biomedical ethics. Most immunization-specific literature focuses upon scientific research, immunization recommendations, and disease-related morbidity and mortality rates. Public health officials medically justify mass immunization but the question that is virtually left unanswered by existing literature is whether or not mass immunization is ethically justifiable. The ethical discussion will be grounded in findings from international scientific, medical, epidemiological, and legal documents. This thesis is primarily concerned with the ethical implications of mass immunization within a Canadian context. (Abstract shortened by UMI.)Dept. of Religious Studies. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1998 .D56. Source: Masters Abstracts International, Volume: 39-02, page: 0496. Adviser: Dietmar Lage. Thesis (M.A.)--University of Windsor (Canada), 1998
Quaternary ferrites by batch and continuous flow hydrothermal synthesis: a comparison
Crystalline spinel quaternary ferrites MxZn1−xFe2O4 (M = Co, Ni; x = 0.2, 0.35, 0.5, 0.65, 0.8) were synthesised through conventional batch hydrothermal synthesis (HT) at 135 °C as well as via continuous flow hydrothermal synthesis (CHFS). The as prepared compounds were thoroughly characterised from a compositional (ICP-MS, XPS) and structural (XRD) point of view in order to compare the synthetic approaches and achieve a greater understanding of how the chosen approach influences the characteristics of the resulting spinel
Tri-critical behavior in rupture induced by disorder
We discover a qualitatively new behavior for systems where the load transfer
has limiting stress amplification as in real fiber composites. We find that the
disorder is a relevant field leading to tri--criticality, separating a
first-order regime where rupture occurs without significant precursors from a
second-order regime where the macroscopic elastic coefficient exhibit power law
behavior. Our results are based on analytical analysis of fiber bundle models
and numerical simulations of a two-dimensional tensorial spring-block system in
which stick-slip motion and fracture compete.Comment: Revtex, 10 pages, 4 figures available upon reques
Self-Organized Criticality Driven by Deterministic Rules
We have investigated the essential ingredients allowing a system to show Self
Organized Criticality (SOC) in its collective behavior. Using the Bak-Sneppen
model of biological evolution as our paradigm, we show that the random
microscopic rules of update can be effectively substituted with a chaotic map
without changing the universality class. Using periodic maps SOC is preserved,
but in a different universality class, as long as the spectrum of frequencies
is broad enough.Comment: 4 pages, RevTex (tar.gz), 4 eps-figures include
Vibrational spectra and normal coordinate analysis of CF 3 OF and CF 3 OCl
The IR spectra (1400 cm −1 to 160 cm −1 ) of the gases at ambient temperature and the Raman spectra (below 1400 cm −1 ) of the liquids near −196°C are reported for CF 3 OF and CF 3 OCl. All fundamentals are assigned under C s symmetry and the results of a normal coordinate analysis are presented. The assignments of Smardzewski and Fox are adopted with one exception for both CF 3 OF and CF 3 OCl: the CF 3 rock of A ″ symmetry is assigned near 430 cm −1 and the two bands between 200 cm −1 and 300 cm −1 are assigned to an A ′ fundamental, involving CF 3 rocking and COX bending and a Δ ν =2 transition in the CF 3 torsion. An extra band at 548 cm −1 in the Raman spectrum of liquid CF 3 COl near −196°C is assigned to a CF 3 OCl ⃛Cl 2 complex. The values of the force constants d (OX) for CF 3 OX molecules are suggested to be near those for X 2 O molecules. More than half the normal modes of A ′ symmetry show extensive mixing of symmetry coordinates. In some of these cases the symmetry coordinate for which the normal mode is named is the largest but not the dominant contributor to the potential energy distribution, while in others this symmetry coordinate is not even the largest contributor to the potential energy distribution. No normal modes of A ′ symmetry are present in which ν(CO), δ s (CF 3 ), δ(COX), or δ(CF 3 ) symmetry coordinates are dominant, and the mode conventionally labeled as v (CO) should be labeled as ν s (CF 3 ). For the remaining A ′ normal modes and all the A ″ normal modes, the symmetry coordinate for which the normal mode is named is dominant in the potential energy distribution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91176/1/1250090406_ftp.pd
Avalanches in Breakdown and Fracture Processes
We investigate the breakdown of disordered networks under the action of an
increasing external---mechanical or electrical---force. We perform a mean-field
analysis and estimate scaling exponents for the approach to the instability. By
simulating two-dimensional models of electric breakdown and fracture we observe
that the breakdown is preceded by avalanche events. The avalanches can be
described by scaling laws, and the estimated values of the exponents are
consistent with those found in mean-field theory. The breakdown point is
characterized by a discontinuity in the macroscopic properties of the material,
such as conductivity or elasticity, indicative of a first order transition. The
scaling laws suggest an analogy with the behavior expected in spinodal
nucleation.Comment: 15 pages, 12 figures, submitted to Phys. Rev. E, corrected typo in
authors name, no changes to the pape
ANKRd44 gene silencing: A putative role in trastuzumab resistance in HER2-like breast cancer
Trastuzumab is an effective therapeutic treatment for Her2-like breast cancer; despite this most of these tumors develop resistance to therapy due to specific gene mutations or alterations in gene expression. Understanding the mechanisms of resistance to Trastuzumab could be a useful tool in order to identify combinations of drugs that elude resistance and allow a better response for the treated patients. Twelve primary biopsies of Her2+/hormone receptor negative (ER-/PgR-) breast cancer patients were selected based on the specific response to neoadjuvant therapy with Trastuzumab and their whole exome was sequenced leading to the identification of 18 informative gene mutations that discriminate patients selectively based on response to treatment. Among these genes, we focused on the study of the ANKRD44 gene to understand its role in the mechanism of resistance to Trastuzumab. The ANKRD44 gene was silenced in Her2-like breast cancer cell line (BT474), obtaining a partially Trastuzumab-resistant breast cancer cell line that constitutively activates the NF-kb protein via the TAK1/AKT pathway. Following this activation an increase in the level of glycolysis in resistant cells is promoted, also confirmed by the up-regulation of the LDHB protein and by an increased TROP2 protein expression, found generally associated with aggressive tumors. These results allow us to consider the ANKRD44 gene as a potential gene involved in Trastuzumab resistance
Self-organization and annealed disorder in a fracturing process
We show that a vectorial model for inhomogeneous elastic media self-organizes under external stress. An onset of crack avalanches of every duration and length scale compatible with the lattice size is observed. The behavior is driven by the introduction of annealed disorder, i.e., by lowering the breaking threshold in the neighborhood of a bond broken by the stress, with a process similar to self-organized criticality. A further comparison with experimental results of acoustic emission (AE), shows that the stability of the elastic potential energy of the system in the AE regime is a sufficient condition for reproducing the algebraic distribution of the energy released during cracks formation
Statistical properties of microcracking in polyurethane foams under tensile test, influence of temperature and density
We report tensile failure experiments on polyurethane (PU) foams. Experiments
have been performed by imposing a constant strain rate. We work on
heterogeneous materials for whom the failure does not occur suddenly and can
develop as a multistep process through a succession of microcracks that end at
pores. The acoustic energy and the waiting times between acoustic events follow
power-law distributions. This remains true while the foam density is varied.
However, experiments at low temperatures (PU foams more brittle) have not
yielded power-laws for the waiting times. The cumulative acoustic energy has no
power law divergence at the proximity of the failure point which is
qualitatively in agreement with other experiments done at imposed strain. We
notice a plateau in cumulative acoustic energy that seems to occur when a
single crack starts to propagate
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