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Search Results: 1 - 10 of 412 matches for " Saskia Schadow "
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Collagen Metabolism of Human Osteoarthritic Articular Cartilage as Modulated by Bovine Collagen Hydrolysates
Saskia Schadow, Hans-Christian Siebert, Günter Lochnit, Jens Kordelle, Markus Rickert, Jürgen Steinmeyer
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053955
Abstract: Destruction of articular cartilage is a characteristic feature of osteoarthritis (OA). Collagen hydrolysates are mixtures of collagen peptides and have gained huge public attention as nutriceuticals used for prophylaxis of OA. Here, we evaluated for the first time whether different bovine collagen hydrolysate preparations indeed modulate the metabolism of collagen and proteoglycans from human OA cartilage explants and determined the chemical composition of oligopeptides representing collagen fragments. Using biophysical techniques, like MALDI-TOF-MS, AFM, and NMR, the molecular weight distribution and aggregation behavior of collagen hydrolysates from bovine origin (CH-Alpha?, Peptan? B 5000, Peptan? B 2000) were determined. To investigate the metabolism of human femoral OA cartilage, explants were obtained during knee replacement surgery. Collagen synthesis of explants as modulated by 0–10 mg/ml collagen hydrolysates was determined using a novel dual radiolabeling procedure. Proteoglycans, NO, PGE2, MMP-1, -3, -13, TIMP-1, collagen type II, and cell viability were determined in explant cultures. Groups of data were analyzed using ANOVA and the Friedman test (n = 5–12). The significance was set to p≤0.05. We found that collagen hydrolysates obtained from different sources varied with respect to the width of molecular weight distribution, average molecular weight, and aggregation behavior. None of the collagen hydrolysates tested stimulated the biosynthesis of collagen. Peptan? B 5000 elevated NO and PGE2 levels significantly but had no effect on collagen or proteoglycan loss. All collagen hydrolysates tested proved not to be cytotoxic. Together, our data demonstrate for the first time that various collagen hydrolysates differ with respect to their chemical composition of collagen fragments as well as by their pharmacological efficacy on human chondrocytes. Our study underscores the importance that each collagen hydrolysate preparation should first demonstrate its pharmacological potential both in vitro and in vivo before being used for both regenerative medicine and prophylaxis of OA.
The one-pion-exchange three-nucleon force and the $A_y$ puzzle
L. Canton,W. Schadow
Physics , 2000, DOI: 10.1103/PhysRevC.64.031001
Abstract: We consider a new three-nucleon force generated by the exchange of one pion in the presence of a 2N correlation. The underlying irreducible diagram has been recently suggested by the authors as a possible candidate to explain the puzzle of the vector analyzing powers $A_y$ and $iT_{11}$ for nucleon-deuteron scattering. Herein, we have calculated the elastic neutron-deuteron differential cross section, $A_y$, $iT_{11}$, $T_{20}$, $T_{21}$, and $T_{22}$ below break-up threshold by accurately solving the Alt-Grassberger-Sandhas equations with realistic interactions. We have also studied how $A_y$ evolves below 30 MeV. The results indicate that this new 3NF diagram provides one possible additional contribution, with the correct spin-isospin structure, for the explanation of the origin of this puzzle.
Radiative capture of protons by deuterons
W. Schadow,W. Sandhas
Physics , 1998, DOI: 10.1103/PhysRevC.59.607
Abstract: The differential cross section for radiative capture of protons by deuterons is calculated using different realistic NN interactions. We compare our results with the available experimental data below $E_x = 20 MeV$. Excellent agreement is found when taking into account meson exchange currents, dipole and quadrupole contributions, and the full initial state interaction. There is only a small difference between the magnitudes of the cross sections for the different potentials considered. The angular distributions, however, are practically potential independent.
Photodisintegration of the triton with realistic potentials
W. Schadow,W. Sandhas
Physics , 1997, DOI: 10.1103/PhysRevC.55.1074
Abstract: The process $\gamma + t \to n + d$ is treated by means of three-body integral equations employing in their kernel the W-Matrix representation of the subsystem amplitudes. As compared to the plane wave (Born) approximation the full solution of the integral equations, which takes into account the final state interaction, shows at low energies a 24% enhancement. The calculations are based on the semirealistic Malfliet-Tjon and the realistic Paris and Bonn B potentials. For comparison with earlier calculations we also present results for the Yamaguchi potential. In the low-energy region a remarkable potential dependence is observed, which vanishes at higher energies.
Triton photodisintegration with realistic potentials
W. Schadow,W. Sandhas
Physics , 1997, DOI: 10.1016/S0375-9474(98)00072-4
Abstract: The photodisintegration of $^{3}$H is treated by means of coupled integral equations using separable versions of the Paris and the Bonn potentials in their kernel. The differential cross section for the inverse reaction is obtained via detailed balance. For the latter process good agreement with the data is found when including final-state interaction, meson exchange currents, higher partial waves in the potential, and electric quadrupole contributions in the electromagnetic interaction.
Why is the three-nucleon force so odd?
L. Canton,W. Schadow
Physics , 2000, DOI: 10.1103/PhysRevC.62.044005
Abstract: By considering a class of diagrams which has been overlooked also in the most recent literature on three-body forces, we extract a new contribution to the three-nucleon interaction which specifically acts on the triplet odd states of the two nucleon subsystem. In the static approximation, this 3N-force contribution is fixed by the underlying 2N interaction, so in principle there are no free parameters to adjust. The 2N amplitude however enters in the 3NF diagram in a form which cannot be directly accessed or constrained by NN phase-shift analysis. We conclude that this new 3N-force contribution provides a mechanism which implies that the presence of the third nucleon modifies the p-wave (and possibly the f-wave) components of the 2N subsystem in the triplet-isotriplet channels.
The pd <--> pi+ t reaction around the Delta resonance
Luciano Canton,Wolfgang Schadow
Physics , 1997, DOI: 10.1103/PhysRevC.56.1231
Abstract: The pd <--> pi+ t process has been calculated in the energy region around the Delta-resonance with elementary production/absorption mechanisms involving one and two nucleons. The isobar degrees of freedom have been explicitly included in the two-nucleon mechanism via pi-- and rho-exchange diagrams. No free parameters have been employed in the analysis since all the parameters have been fixed in previous studies on the simpler pp <--> pi+ d process. The treatment of the few-nucleon dynamics entailed a Faddeev-based calculation of the reaction, with continuum calculations for the initial p-d state and accurate solutions of the three-nucleon bound-state equation. The integral cross-section was found to be quite sensitive to the NN interaction employed while the angular dependence showed less sensitivity. Approximately a 4% effect was found for the one-body mechanism, for the three-nucleon dynamics in the p-d channel, and for the inclusion of a large, possibly converged, number of three-body partial states, indicating that these different aspects are of comparable importance in the calculation of the spin-averaged observables.
Isoscalar off-shell effects in threshold pion production from pd collisions
L. Canton,W. Schadow
Physics , 1999, DOI: 10.1103/PhysRevC.61.064009
Abstract: We test the presence of pion-nucleon isoscalar off-shell effects in the $pd\to \pi^+ t$ reaction around the threshold region. We find that these effects significantly modify the production cross section and that they may provide the missing strength needed to reproduce the data at threshold.
Influence of the Multispecies Probiotic Ecologic® BARRIER on Parameters of Intestinal Barrier Function  [PDF]
Saskia Van Hemert, Geline Ormel
Food and Nutrition Sciences (FNS) , 2014, DOI: 10.4236/fns.2014.518187
Abstract: The intestinal epithelium is a single cell layer that forms the largest and most important barrier against the external environment. A proper functioning of the intestinal barrier is essential for maintaining optimal health. A disrupted intestinal barrier function has been associated with the development of autoimmune and inflammatory diseases. Probiotics are live microorganisms that confer a health benefit to the host and have been associated with prevention of diseases such as antibiotic-associated diarrhea, irritable bowel syndrome and inflammatory bowel disease. Probiotics can improve and restore the intestinal barrier function in diverse ways and effects are thought to be species- and even strain-specific. With this research the influence of probiotic bacteria in Ecologic? BARRIER on parameters of intestinal barrier function was investigated. The results show that each bacterial strain in Ecologic?BARRIER is in vitro capable to improve the epithelial barrier in diverse ways.
Localizando ciudades en circuitos globales
Sassen,Saskia;
EURE (Santiago) , 2003, DOI: 10.4067/S0250-71612003008800001
Abstract: there have long been cross-border economic processes. in the last hundred years, the inter-state system came to provide the dominant organizational form cross-border flows, with national states as its key actors. this condition has changed dramatically over the last decade and more, as a result of privatization, deregulation, the opening up of national economies to foreign firms and the growing participation of national economic actors in global markets. in this context, we see a re-scaling of what are the strategic territories that articulate the new system. the organizational architecture for cross-border flows that results from these re-scaling and articulations increasingly diverges from that of the inter-state system. my central effort here is to contribute to empirical and theoretical specification of this organizational architecture. among the features examined here are the combination of centralization and dispersal trends, the disproportionate concentration of value and transactions in the north atlantic, the role of cities in an increasingly digitized global economy, especially as illustrated by the growth of finance and specialized services, and the impact of information technologies on urban economies
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