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Search Results: 1 - 10 of 1949 matches for " Norbert Stockhofe-Zurwieden "
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Serum protein profiles as potential biomarkers for infectious disease status in pigs
Miriam GJ Koene, Han A Mulder, Norbert Stockhofe-Zurwieden, Leo Kruijt, Mari A Smits
BMC Veterinary Research , 2012, DOI: 10.1186/1746-6148-8-32
Abstract: Protein profiles were generated by SELDI-TOF mass spectrometry in combination with the Proteominer? technology to enrich for low-abundance proteins. Based on these protein profiles, the experimentally infected pigs could be classified according to their infectious disease status. Before the onset of clinical signs 88% of the infected animals could be classified correctly, after the onset of clinical sigs 93%. The sensitivity of the classification appeared to be high. The protein profiles could distinguish between separate infection models, although specificity was moderate to low. Classification of PCV2/PRRSV infected animals was superior compared to PCV2/PPV infected animals. Limiting the number of proteins in the profiles (ranging from 568 to 10) had only minor effects on the classification performance.This study shows that serum protein profiles have potential for detection and identification of viral infections in pigs before clinical signs of the disease become visible.In present livestock husbandry with increasing requirements for higher health and welfare issues but also tight economical margins, there is a need for tools allowing the early warning for disease. Ideally, easy to perform tools should be available that warn farmers and veterinarians that animals are infected, preferably before the onset of clinical signs. Regular use of such tools may diminish growth retardations and production losses. However, tests for early diagnosis can only be developed when animal-associated "biomarkers" exist that differ between uninfected healthy animals and infected, but not yet diseased, animals. The search for such biomarkers can be performed by two different approaches, either focusing on differences in predefined "candidate" markers, or by comparative fingerprint analysis of "all" components present in a biological sample.In human medicine extensive research has been performed aiming at the discovery of early biomarkers for different kinds of disease, including canc
The course of hepatitis E virus infection in pigs after contact-infection and intravenous inoculation
Martijn Bouwknegt, Saskia A Rutjes, Chantal BEM Reusken, Norbert Stockhofe-Zurwieden, Klaas Frankena, Mart CM de Jong, Ana Maria de Roda Husman, Wim HM van der Poel
BMC Veterinary Research , 2009, DOI: 10.1186/1746-6148-5-7
Abstract: To resemble natural transmission, 24 HEV-susceptible pigs were infected either by one-to-one exposure to intravenously inoculated pigs (C1-pigs; n = 10), by one-to-one exposure to contact-infected pigs (C2-pigs: n = 7; C3-pigs: n = 5) or due to an unknown non-intravenous infection route (one C2-pig and one C3-pig). The course of HEV-infection for contact-infected pigs was characterized by: faecal HEV RNA excretion that started at day 7 (95% confidence interval: 5–10) postexposure and lasted 23 (19–28) days; viremia that started after 13 (8–17) days of faecal HEV RNA excretion and lasted 11 (8–13) days; antibody development that was detected after 13 (10–16) days of faecal HEV RNA excretion. The time until onset of faecal HEV RNA excretion and onset of viremia was significantly shorter for iv-pigs compared to contact-infected pigs, whereas the duration of faecal HEV RNA excretion was significantly longer. At 28 days postinfection HEV RNA was detected less frequently in organs of contact-infected pigs compared to iv-pigs. For contact-infected pigs, HEV RNA was detected in 20 of 39 muscle samples that were proxies for pork at retail and in 4 of 7 urine samples.The course of infection differed between infection routes, suggesting that contact-infection could be a better model for natural transmission than iv inoculation. Urine and meat were identified as possible HEV-sources for pig-to-pig and pig-to-human HEV transmission.Hepatitis E virus (HEV) is a positive sense, non-enveloped single-stranded RNA virus with a genome of 7.2 kb and can be grouped into at least four genotypes [1]. Hepatitis E virus was considered to be restricted to developing countries, but it is now considered an emerging pathogen in developed countries [e.g. [2]]. The epidemiology of HEV, however, differs between developed and developing countries [1]. In developing countries all four genotypes of HEV are found in locally acquired hepatitis E cases, whereas in developed countries locally acquired HE
Genetic diversity of Streptococcus suis isolates as determined by comparative genome hybridization
Astrid de Greeff, Henk J Wisselink, Freddy M de Bree, Constance Schultsz, Christoph G Baums, Hoa Thi, Norbert Stockhofe-Zurwieden, Hilde E Smith
BMC Microbiology , 2011, DOI: 10.1186/1471-2180-11-161
Abstract: In this study, the correlation between gene content, serotype, phenotype and virulence among 55 S. suis strains was studied using Comparative Genome Hybridization (CGH). Clustering of CGH data divided S. suis isolates into two clusters, A and B. Cluster A isolates could be discriminated from cluster B isolates based on the protein expression of extracellular factor (EF). Cluster A contained serotype 1 and 2 isolates that were correlated with virulence. Cluster B mainly contained serotype 7 and 9 isolates. Genetic similarity was observed between serotype 7 and serotype 2 isolates that do not express muramidase released protein (MRP) and EF (MRP-EF-), suggesting these isolates originated from a common founder. Profiles of 25 putative virulence-associated genes of S. suis were determined among the 55 isolates. Presence of all 25 genes was shown for cluster A isolates, whereas cluster B isolates lacked one or more putative virulence genes. Divergence of S. suis isolates was further studied based on the presence of 39 regions of difference. Conservation of genes was evaluated by the definition of a core genome that contained 78% of all ORFs in P1/7.In conclusion, we show that CGH is a valuable method to study distribution of genes or gene clusters among isolates in detail, yielding information on genetic similarity, and virulence traits of S. suis isolates.Streptococcus suis forms a problem in the swine industry. Clinically healthy sows carry S. suis in their nasal cavities and on their tonsils, and transmit the bacteria to their piglets [1], that develop a variety of infections, such as septicaemia, meningitis, polyarthritis, and endocarditis, and often do not survive [2]. S. suis occasionally causes meningitis, arthritis or endocarditis in humans. However, recently several large human outbreaks of S. suis have been described in China [3,4], and Thailand [5], whilst S. suis meningitis has become endemic in Vietnam [6,7], suggesting that isolates that are more virulent t
Sub- and supercritical defect scattering in Schr?dinger chains with higher-order hopping
J. Stockhofe,P. Schmelcher
Physics , 2015, DOI: 10.1103/PhysRevA.92.023605
Abstract: We theoretically analyze a discrete Schr\"odinger chain with hopping to the first and second neighbors, as can be realized with zigzag arrangements of optical waveguides or lattice sites for cold atoms. Already at moderate values, the second-neighbor hopping has a strong impact on the band structure, leading to the emergence of a new extremum located inside the band, accompanied by a van Hove singularity in the density of states. The energy band is then divided into a subcritical regime with the usual unique correspondence between wave number and energy of the travelling waves, and a supercritical regime, in which waves of different wave number are degenerate in energy. We study the consequences of these features in a scattering setup, introducing a defect that locally breaks the translational invariance. The notion of a local probability current is generalized beyond the nearest-neighbor approximation and bound states with energies outside the band are discussed. At subcritical energies inside the band, an evanescent mode coexists with the travelling plane wave, giving rise to resonance phenomena in scattering. At weak coupling to the defect, we identify a prototypical Fano-Feshbach resonance of tunable shape and provide analytical expressions for its profile parameters. At supercritical energies, we observe coupling of the degenerate travelling waves, leading to an intricate wave packet fragmentation dynamics. The corresponding branching ratios are analyzed.
Nonadiabatic couplings and gauge-theoretical structure of curved quantum waveguides
J. Stockhofe,P. Schmelcher
Physics , 2013, DOI: 10.1103/PhysRevA.89.033630
Abstract: We investigate the quantum mechanics of a single particle constrained to move along an arbitrary smooth reference curve by a confinement that is allowed to vary along the waveguide. The Schr\"odinger equation is evaluated in the adapted coordinate frame and a transverse mode decomposition is performed, taking into account both curvature and torsion effects and the possibility of a cross-section potential that changes along the curve in an arbitrary way. We discuss the adiabatic structure of the problem, and examine nonadiabatic couplings that arise due to the curved geometry, the varying transverse profile and their interplay. The exact multi-mode matrix Hamiltonian is taken as the natural starting point for few-mode approximations. Such approximate equations are provided, and it is worked out how these recover known results for twisting waveguides and can be applied to other types of waveguide designs. The quantum waveguide Hamiltonian is recast into a form that clearly illustrates how it generalizes the Born-Oppenheimer Hamiltonian encountered in molecular physics. In analogy to the latter, we explore the local gauge structure inherent to the quantum waveguide problem and suggest the usefulness of diabatic states, giving an explicit construction of the adiabatic-to-diabatic basis transformation.
Bloch dynamics in lattices with long range hoppings
J. Stockhofe,P. Schmelcher
Physics , 2014, DOI: 10.1103/PhysRevA.91.023606
Abstract: We study a discrete Schr\"odinger equation with arbitrary long range hopping terms under the influence of an external force. The impact of long range hoppings on the single particle Bloch dynamics in the lattice is investigated. A closed expression for the propagator is given, based on which we analyze the dynamics of initially Gaussian wave packets. Our findings capture the anharmonic oscillations recently observed in zigzag lattices and furthermore provide a detailed quantitative description of the crossover between center of mass Bloch oscillations for wide wave packets and left-right symmetric width oscillations for narrow single site excitations. The analytical results are shown to be in agreement with numerical simulations. A helix lattice setup for ultracold atoms is proposed where such hopping terms to far neighbors can be experimentally tuned to sizable values.
Modulational instability and localized breather modes in the discrete nonlinear Schr?dinger equation with helicoidal hopping
J. Stockhofe,P. Schmelcher
Physics , 2015,
Abstract: We study a one-dimensional discrete nonlinear Schr\"odinger model with hopping to the first and a selected N-th neighbor, motivated by a helicoidal arrangement of lattice sites. We provide a detailed analysis of the modulational instability properties of this equation, identifying distinctive multi-stage instability cascades due to the helicoidal hopping term. Bistability is a characteristic feature of the intrinsically localized breather modes, and it is shown that information on the stability properties of weakly localized solutions can be inferred from the plane-wave modulational instability results. Based on this argument, we derive analytical estimates of the critical parameters at which the fundamental on-site breather branch of solutions turns unstable. In the limit of large N, these estimates predict the emergence of an effective threshold behavior, which can be viewed as the result of a dimensional crossover to a two-dimensional square lattice.
The Impact of Thermal Modeling on Limiting RF-EMF  [PDF]
Norbert Leitgeb
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2013, DOI: 10.4236/jemaa.2013.54022

The paper quantitatively assesses the relationship between specific energy absorption rates (SAR) of radio frequency (RF) electromagnetic fields (EMF) and resulting intracorporal tissue temperature changes (ΔT) at whole body exposure of a small person to resonant RF EMF. Applied thermal modeling allowed accounting also for dynamic thermoregulatory responses. As expected from physical laws the correlation of all local SAR values and ΔT data was fairly good. However, at local level SAR proved to be only weakly associated with ΔT. Even if averaged, over any 10 g tissue the ratio ΔT10g/SAR10g still varied by almost two orders of magnitudes. Blood perfusion was found to play a major role in affecting local temperature changes and caused even net cooling. The results demonstrate that local SAR is a poor surrogate for local temperature change, and that conventional static thermal modeling underestimates body core temperature. Results demonstrated that recommended reference levels of RF EMF fail to reliably prevent from exceeding yet legally binding basic restrictions not only with regard to whole-body SAR

Improved diagnosis of human joint  [PDF]
Norbert Leitgeb
Open Journal of Clinical Diagnostics (OJCD) , 2013, DOI: 10.4236/ojcd.2013.34030
Abstract: Today, among the general population the prevalence of joint disorders is increasing even at younger ages. Since therapeutic means are sparse, early awareness of potential health problems is the most important to timely start adequate prevention. The presented improved approach of acoustic joint assessment (ACOJA) is based on subsequently measured acoustic signals emitted by joints at two different mechanical load conditions with the same measurement setup, and analysing the related relative spectral signal changes. While this approach applies to almost any joint, this paper concentrates on demonstrating the capability of this approach at hip joints. It could be demonstrated that the ACOJA method is sensible enough to allow even quantification of age-related degradations at hip normal biological human joints. It allows even identifying and accounting for gender-related differences in hip joint status. This allows concluding that ACOJA will contribute to enlarge the medical possibilities of non-invasive joint diagnostics.
Synoptic Analysis of Epidemiologic Evidence of Brain Cancer Risks from Mobile Communication  [PDF]
Norbert Leitgeb
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2014, DOI: 10.4236/jemaa.2014.614043
Abstract: In the radio frequency (RF) range concern about long-term health risks from electromagnetic fields (EMF) is enhanced by contradictory results and conclusions from epidemiologic studies. A new approach of a synoptic analysis of all available data from epidemiological studies published since 2001 was performed. This approach provided new insight with regard to a potential link between mobile phone use and brain cancer. Two quite different data pools could be identified with numerous studies from one research group opposing all other studies. However, it could be shown that with the number of exposed cases both data pools exhibit a clear trend of risk estimates (odds ratios) towards the final result, namely a reduced cancer risk of OR = 0.8, though from either side of the zero-risk line. The analysis of potential long-term effects indicated by a dosedependence revealed diverging results with different dose metrics. Overall, the synoptic analysis supports reassuring rather than alarming conclusions on RF EMF health risks from mobile telecommunication.
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