1,124 research outputs found
Meat Juice serology underestimates prevalence of Salmonella in pig herds
Salmonella serology is used for classifying pig herds in risk categories in several national quality programs. Meat juice is used as test matrix in most of these programs. Two studies were done to compare the salmonella ELISA test results from meat juice with blood serum as a reference. Pig blood and meat samples for these studies were collected in one slaughterhouse. ELISA tests were done with a commonly applied commercial test. In the first study paired blood serum and meat juice samples from 182 pigs were collected and tested in two different laboratories. In the second study meat and blood samples were collected from 470 herds, over 20.000 samples for each matrix
Dose-response relationship of fibrous dusts in intraperitoneal studies.
The relationship between the number of fibers injected intraperitoneally and the occurrence of peritoneal mesotheliomas in rats was investigated using data from a series of carcinogenicity studies with several fibrous dusts. Based on observed tumor incidences ranging between 10 and 90%, the hypothesis of a common slope of dose-response relationships (parallel probit lines in probit analysis) cannot be rejected. In general, parallelism of probit lines is considered an indication of a common mode of action. Analysis of the shape of the dose-response relationship, with one apparent exception, shows virtually linear or superlinear behavior, i.e., from these data, there is no indication of a decrease in carcinogenic potency of an elementary carcinogenic unit at lower doses
Pion photoproduction on the nucleon in the quark model
We present a detailed quark-model study of pion photoproduction within the
effective Lagrangian approach. Cross sections and single-polarization
observables are investigated for the four charge channels, , , , and .
Leaving the coupling strength to be a free parameter, we obtain a
reasonably consistent description of these four channels from threshold to the
first resonance region. Within this effective Lagrangian approach, strongly
constrainted by the quark model, we consider the issue of double-counting which
may occur if additional {\it t}-channel contributions are included.Comment: Revtex, 35 pages, 16 eps figures; version to appear on PR
Photon Structure and Quantum Fluctuation
Photon structure derives from quantum fluctuation in quantum field theory to
fermion and anti-fermion, and has been an experimentally established feature of
electrodynamics since the discovery of the positron. In hadronic physics, the
observation of factorisable photon structure is similarly a fundamental test of
the quantum field theory Quantum Chromodynamics (QCD). An overview of
measurements of hadronic photon structure in e+e- and ep interactions is
presented, and comparison made with theoretical expectation, drawing on the
essential features of photon fluctuation into quark and anti-quark in QCD.Comment: 29 pages, 15 figures, to appear in Philosophical Transactions of the
Royal Society of London (Series A: Mathematical, Physical and Engineering
Sciences
Effects of Surface Coatings on the Joint Formation During Magnetic Pulse Welding in Tube-to-Cylinder Configuration
Magnetic Pulse Welding (MPW) is a joining technique favorable for the generation of
strong atomic bonded areas between different metals, e.g. aluminum and steel. Brittle
intermetallic phases can be avoided due to the high-speed collision and the absence of
external heat. The demand for the use of this technique in industries like automotive and
plant engineering rises. However, workpieces used in these fields are often coated, e.g. in
order to improve the corrosion resistance. Since the weld quality depends on the material’s
behavior at the collision zone, surface layers in that region have to be taken into account
as well.
This work investigates the influences of different coating types. Aluminum to steel
welding is used as an example system. On the inner steel part (C45) coatings like zinc,
nickel and chrome are applied, while the aluminum flyer tubes (EN AW-6060) are
anodized, chromated and passivated. Welding tests are performed using two different
welding systems with varying discharging frequencies and four geometrical part setups.
For all combinations, the flyer velocity during the process is measured by Photon Doppler
Velocimetry (PDV). By using the uncoated material combination as a reference, the
removal of surface layers due to jetting is analyzed. Finally, the weld quality is
characterized in peel tests, shear-push tests and by the help of metallographic analysis. It
is found that certain coatings improve the joint formation, while others are obstructive for
the performance of MPW. Some coatings have no influence on the joining process at all
Experiences with a risk based meat inspection standard in pigs
The European Union legislation provides several possibilities to modernize meat inspection. Improvement of food safety by active contribution of food business operators in the supply chain being responsible for food safety is envisaged in these new standards
Influence of Axial Workpiece Positioning during Magnetic Pulse Welding of Aluminum-Steel Joints
Magnetic Pulse Welding (MPW) offers a method to economically join similar and dissimilar
metals without the need for external physical or chemical binders, while avoiding the
adverse heating effects seen in many welding techniques. MPW allows for the fabrication
of joints via the harnessing of Lorentz forces, which result from discharging a current
pulse through a coil. In the process an outer piece (flyer) is accelerated onto an inner
piece (parent), and welding is achieved using propagating impact fronts. There are
several geometrical factors to be considered including the flyer-coil distance, the parentflyer
distance, as well as the axial relationship between flyer and coil (working length).
Various shapes of the front are possible and each configuration has its own advantages
and drawbacks. The goal of this work is to show not only how the aforementioned
parameters are related, but also ways to optimize front propagations, which are vital to the
welding result. This is done primarily by determining the influence of the working length of
tubular MPW specimens. It is shown that for steel-aluminum joints in the given
arrangements, three different front regimes exist, which are related to geometrical factors.
These results are especially useful to avoid seemingly favorable but nevertheless
suboptimal conditions for flyer movement that would reduce weld quality and energy
efficiency of the process
An SU(3) model for octet baryon and meson fragmentation
The production of the octet of baryons and mesons in e^+ e^- collisions is
analysed, based on considerations of SU(3) symmetry and a simple model for
SU(3) symmetry breaking in fragmentation functions. All fragmentation
functions, D_q^h(x, Q^2), describing the fragmentation of quarks into a member
of the baryon octet (and similarly for fragmentation into members of the meson
octet) are expressed in terms of three SU(3) symmetric functions, \alpha(x,
Q^2), \beta(x, Q^2), and \gamma(x, Q^2). With the introduction of an SU(3)
breaking parameter, \lambda, the model is successful in describing
hadroproduction data at the Z pole. The fragmentation functions are then
evolved using leading order evolution equations and good fits to currently
available data at 34 GeV and at 161 GeV are obtained.Comment: 24 pages LaTeX file including 11 postscript figure file
Targeting tachykinin receptors in neuroblastoma
Neuroblastoma is the most common extracranial tumor in children. Despite aggressive multimodal treatment, high-risk neuroblastoma remains a clinical challenge with survival rates below 50%. Adding targeted drugs to first-line therapy regimens is a promising approach to improve survival in these patients. TACR1 activation by substance P has been reported to be mitogenic in cancer cell lines. Tachykinin receptor (TACR1) antagonists are approved for clinical use as an antiemetic remedy since 2003. Tachykinin receptor inhibition has recently been shown to effectively reduce growth of several tumor types. Here, we report that neuroblastoma cell lines express TACR1, and that targeting TACR1 activity significantly reduced cell viability and induced apoptosis in neuroblastoma cell lines. Gene expression profiling revealed that TACR1 inhibition repressed E2F2 and induced TP53 signaling. Treating mice harboring established neuroblastoma xenograft tumors with Aprepitant also significantly reduced tumor burden. Thus, we provide evidence that the targeted inhibition of tachykinin receptor signaling shows therapeutic efficacy in preclinical models for high-risk neuroblastoma
Leading particle effect, inelasticity and the connection between average multiplicities in {\bf } and {\bf } processes
The Regge-Mueller formalism is used to describe the inclusive spectrum of the
proton in collisions. From such a description the energy dependences of
both average inelasticity and leading proton multiplicity are calculated. These
quantities are then used to establish the connection between the average
charged particle multiplicities measured in {\bf } and {\bf } processes. The description obtained for the leading proton cross section
implies that Feynman scaling is strongly violated only at the extreme values of
, that is at the central region () and at the diffraction
region (), while it is approximately observed in the
intermediate region of the spectrum.Comment: 20 pages, 10 figures, to be published in Physical Review
- …